User manual | Ask the Wireless Wizard

NEW DIRECTIONS IN WIRELESS
Ask the
Wireless
Wizard
•
Scott Goldman
A HOWNET PRODUCTION
The Edmond-Howard Network
Copyright ©2000 by The Edmond-Howard Network, an association of wireless communications
consultants. All rights reserved. No part of this work covered by the copyrights hereon may be
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to my dear friend, Mort Spector,
who taught me
you’re never too old to learn
or too smart to listen
His knowledge, wit & intellect
have been inspirational to me
– as has his commitment
to learning about technology
when other people his age
would be playing shuffleboard.
An all-around swell guy.
Thanks for everything, Mort.
Contents
1
Who is The Wireless Wizard? 7
Why does he hates wires? 7
Where did all these questions come from? 8
What can The Wireless Wizard teach you? 8
2
A brief history of, well, a brief history 9
How did The Titanic disaster lead to a worldwide movement promoting
the use of wireless? 10
How did WWII walkie-talkies lead to today’s wireless? 10
Why were waiting lines sometimes years long to get a mobile telephone,
when the technology was so antiquated? 12
What was the big improvement that we might laugh at today? 13
Why is advanced better than improved? 13
What is the Public Switched Telephone Network & why do we need it? 14
3
What makes this mysterious radio stuff work? 15
What can The Beach Boys and country lakes teach us about how radio
waves work? 15
Who was Mr. Hertz (not the rental car guy) and why did we name the
measurement of radio frequencies in his honor? 16
But why do I see initials in front of the “Hz” abbreviation and what do they
mean? 17
Why are there so many different divisions on a spectrum chart – and what
do they all mean? 17
Why are pagers, two-way radios & wireless phones like traveling on oneway streets, express lanes and interstate highways? 18
How can light bulbs and flashlights help us understand the way that radio
signals are transmitted? 20
4
How do wireless systems work, anyway? 21
What does your favorite FM radio station teach you about the next
advancement in mobile phone technology? 21
So keeping the transmission area small is what makes wireless phone
systems work? 22
I don’t get it … How do you increase capacity by decreasing the size of
cells? 22
What does hand-off mean, and how often does it happen? 23
What really happens when I turn on my phone? 23
How does the system know where I am? 24
How does it let me place a call? 25
How did the “Send” button get such a silly name? 25
What does the send button actually do? 25
How does a call get to me? 26
Why won’t the phone work in some places? Can’t companies just put up
another tower when they need to? 26
5
What are the components of a wireless system? 28
What’s in a cell site? 28
OK, wireless is cool, but the world is shifting to the Internet. Is that going
to change the wireless business, too? 31
How can shipping a car from New York to Los Angeles teach us the
difference between a circuit switched and packet data connection? 32
What’s the difference between analog, CDMA & TDMA technologies? 34
6
What’s the difference between services, standards, and
technologies? Why is it important? 37
How can you win a bet with your boss and prove that everyone refers to
standards, incorrectly, as GSM, TDMA, and CDMA? 37
So why is it so incorrect that everyone in the wireless industry refers to
GSM, TDMA, and CDMA as standards? 39
Why isn’t there a worldwide standard – or at least a worldwide frequency
that all wireless phones work on? 39
7
What makes the wireless industry tick? 40
If the industry is already so successful, where will all the future users come
from? 40
I don’t get it – Why is coverage so lousy in some places? Can’t the wireless
companies just put up another tower site where they need one? 40
Why does the government get involved in regulating some of the stuff? 41
What is churn, and why is it so important for wireless companies to
avoid it? 43
If some countries already have 25%–50% penetration, from where is the
future growth for the wireless industry going to come? 44
I’ve heard some people talking about “3G”. What does that mean? Should it
be important to me? 45
8
What’s next? Is my wireless phone ever going to become
obsolete? Will newer technologies take over? 46
I hear a lot of talk about satellite services. Does the wireless industry use
them now? 46
Has anyone thought about providing Internet access via wireless? Is that
what LMDS is all about? 47
9
The Wizard’s Apprentice 48
GLOSSARY OF WIRELESS INDUSTRY TERMS 49
BIBLIOGRAPHY 67
6
NEW DIRECTIONS IN WIRELESS
NEW DIRECTIONS IN WIRELESS
Ask the Wireless Wizard
1 Who is the Wireless Wizard?
After 25 years in the wireless industry launching new businesses, consulting
with companies around the world and explaining to friends and neighbors how
wireless phones work, Scott Goldman’s friends started calling him the Wireless
Wizard.
His resumé reads like a list of important milestones in the cellular and paging
industries. But his most rewarding work has been teaching thousands of
students in classes around the country how wireless works. His easy, familiar
style is packed with analogies, anecdotes and everyday references that help
demystify the arcane language of radio engineers, physicists and product
designers.
Why does he hate wires?
“I hate wires. Ever since I was a kid I’ve hidden them, buried them and stuffed
them underneath carpets. They’re unmanageable, easy to trip over and make
your house, desk and car look like a spaghetti factory hit by a hurricane.
“From the first time I realized that music and pictures could be transmitted to
my radio and TV without wires (hardly anyone had ever heard of cable TV back
then) I couldn’t understand why anyone would ever want to use a wire when
there was an alternative.
“Stereo speakers, security systems, remote controls, phones – especially phones –
all mystified me. Why did they need wires to work?
“Well it turns out that they don’t. And in today’s – and tomorrow’s – world there
will be fewer and fewer devices requiring wires and more of them without wires
… wireless devices will proliferate – especially phones and other handheld
devices that help people communicate voice and data messages.
“But if you’re in the wireless industry, whether you sell phones, answer customer
service calls or work on a factory’s assembly line, you’ve got to understand How
Things Work in order to better do your job.”
—Scott Goldman
The Wireless Wizard
ASK THE WIRELESS WIZARD
7
Where did all these questions come from?
Wireless manufacturers, carriers and service providers asked The Wireless
Wizard to introduce their new employees, executives transferred from other
divisions, and staff from merged companies to the wireless industry.
Throughout his career he has personally instructed over 2000 people, and his
training materials have been viewed by many more.
The questions in this book are a compilation of the most popular questions
asked during the years of instruction, with the Wizard’s own upbeat, somewhat
irreverent approach flavoring the issues.
What can the Wireless Wizard teach you?
In this book, you’ll learn things like …
± How is the history of wireless phones related to the Titanic, World War II
and St. Louis, Missouri?
± What is the mysterious “spectrum” is and why are big companies willing to
pay very big bucks for it?
± What can The Beach Boys and country lakes teach us about how radio waves
work?
± What do GSM, VSAT, AMPS, CDMA and other acronyms stand for – and
what do they really mean?
± What does the magical “Send” button actually do?
± How are using pagers, two–way radios and wireless phones like traveling on
one–way streets, boulevards at rush hour and interstate highways?
± How the difference between analog, TDMA and CDMA technologies can be
explained by attending three different cocktail parties.
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NEW DIRECTIONS IN WIRELESS
2 A brief history of, well, a brief history
When compared to other technologies, the wireless industry has been around
for a long time. Certainly it has been around longer than computers, aviation or
advanced medicine. Still, in the big scheme of things, it’s been around only a
short time. After all, just 100 years ago the discovery of the whole principle of
radio waves took place. It took many more years before commercial enterprise
finally realized the benefits of applying wireless communications to the needs of
the person on the street.
Like a road map, in order to understand where the industry is going, it helps a
lot to know where you’ve been. And the wireless industry has been a lot of places
you’d never think were related to the business, but they are.
The keys to this industry began in:
± Italy (The first person to make radio actually work lived here)
± The North Atlantic (The Titanic disaster played a key role in worldwide
standards for wireless)
± World War II (The familiar “walkie–talkie” launched here and became the
predecessor to today’s advanced portable wireless phones)
± St. Louis (The first place that wireless phone service – with the option to
place calls yourself instead of going through an operator – launched here)
± Chicago (The was the site of the first test system – and commercial license –
for an “AMPS” service, which laid the foundation for all advanced portable
communications services)
± Scandinavian (Where the first – and to this day, the largest – mobile phone
system employing the technique of frequency reuse* was developed)
*Relax, we’ll explain
this fancy terminology
later.
So let’s take a look at the events that shaped the development of the wireless
business.
ASK THE WIRELESS WIZARD
9
How did the Titanic disaster lead to a worldwide
movement promoting the use of wireless?
You’d have to be living in a cave to have never heard the
story of the sinking of The Titanic. By now, hundreds of
books, films, videos, recordings and other documentation
have told of the sinking in gory, gruesome detail.
What is not known, however, by most people, is that another ship,
The Californian, was only eight miles away – less than an hour – and had stopped
for the night in the midst of an ice field, thinking it unsafe to proceed.
The Californian had a “wireless room” where the newfangled gizmo that allowed
ships to communicate with each other was housed. But there was only one
person on board who knew how to operate the device and he was asleep, after
having shut the wireless receiver off, when the Titanic’s first distress calls were
sent. Thousands of lives could have been saved – but weren’t – if wireless had
been standardized and familiar to the crew of the Californian.
Largely as a result of The Titanic’s disaster, the code of “SOS” was implemented
and wireless rooms on ships were staffed around the clock, after realization
struck about how helpful wireless communications could be.
“SOS” actually means nothing (rumors of it meaning “Save Our Ship” or “Save
Our Souls” are just part of the legend, but untrue). The Morse code representing
“SOS,” three dots, three dashes and three more dots, was thought to be so easy to
“copy” (that’s radio–speak for “receive”) and remember, that it was adopted
universally by ships, planes and other modes of transportation to signal the
ultimate distress call.
How did World War ii “walkie–talkies”
lead to today’s wireless phones?
Walkie–Talkies, a name once trademarked by
Motorola, were the first real application of radio
technology that the general public was familiar with.
Sure, there were police radios before that – and some of them were even
featured in 1930s movies that depicted the good guys vs. the crooks. But for
sheer drama and impact, little could convey the reality of two–way wireless
communications more than watching John Wayne or Robert Mitchum barking
orders into a walkie–talkie as bombs and bullets flew all around them.
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NEW DIRECTIONS IN WIRELESS
These same walkie–talkies led to the proliferation of two–way radios in trucks
and eventually were “interconnected” into the public telephone network,
allowing two–way users the ability to reach – or be reached by – anyone,
anywhere who had access to a phone. Today’s advanced digital wireless phones
are really an evolution of that product. Engineers took the same device, refined
it a thousand times and made the interconnection much simpler, thus bringing
today’s portable handheld wireless phones to market.
As these devices started getting connected to the Public Switched Telephone
Network* (PSTN) they became more useful. Two-way radios not connected to
the PSTN could only contact other two–way radios on the same system.
Connecting them to the PSTN turns them into phones and allows them to reach
– or be reached by – any other phone that is also connected to the PSTN.
BUYING VOWELS
Wireless acronyms explained by watching ‘Wheel of Fortune’
The wireless industry acts a lot like the TV game show,
“Wheel of Fortune.” Whenever we need to name
technologies we look to the name of the original
technology and then we “buy a vowel” in much the same
way that contestants do on TV. We buy “A” for Advanced, “I” for Improved and
“E” for Enhanced.”
i
e
a
You’ll see this in our first example of mobile telephone services, described below.
Ha!
So you think voice recognition is a new technology?
Hooray for technology. It’s so cool that it’s brought the neatest features to our
desks and pockets. One that’s been in the works for a while and is just catching
on now is voice recognition. You know how it works – pick up the phone and
say “Call home” and, like magic, your home number is called automatically. That
is, unless you’re in a very noisy environment or don’t speak clearly, in which case
you might wind up calling Rome instead of home.
There was a time, though, in the wireless business, that voice recognition was
available and was remarkably accurate. That’s because when wireless phones,
then called “mobile phones,” were invented, you couldn’t actually place the call
by yourself. Phones had no dials, buttons or any other way to enter a phone
number. Rather, you picked up the phone and an operator would come on the
line to make the connection for you.
ASK THE WIRELESS WIZARD
11
*The Public Switched
Telephone Network is
the common
connection between
all telephone systems
worldwide. It’s
explained in more
detail later on.
“Hi, Alice
Typically, you’d say,
(the operator’s name, who you got to know
very well after a few calls). Get my office on the line, would you please?”
Officially, however, you were supposed to say, “Hello operator. This is WXYZ123
(your mobile “code”). Please connect me with 999-555-1212 (the number you
wanted to call).” The operator would then place the call from her equipment
and connect you to the other party by means of a bunch of wires plugged into
various holes on an old–fashioned switchboard.
Alice, the mobile
operator of the 40s–
70s, retired in 1974,
and soon after wrote
the disco hit, “Mobile
Codie Spodie Odie”.
Essentially, this form of Mobile Telephone Service (cleverly referred to
by its acronym, MTS) was little more than a two–way radio service that
the operator connected into the PSTN on your behalf. It worked, but it
had lots of limitations. For instance, you had to wait until an operator was
available – there was no way to place the call yourself. There were technical
limitations, too, that made MTS phones difficult to get, tough to use and
inferior sounding.
Why were waiting lists sometimes years long to get a mobile
telephone when the technology was so antiquated?
Well, the technology didn’t seem antiquated at the time. Remember, we’re
talking about the 1940s–1970s. All things considered, this was pretty advanced
stuff. The main problem with Mobile Telephone Services (MTS) can be summed
up in one word – capacity. Let’s examine how MTS actually worked.
Much like the FM radio that you listen to in your car, MTS signals were
transmitted throughout a large metropolitan area. No matter where you were in
that area you could make or receive a phone call on your MTS phone in much
the same way that you can listen to your favorite radio station regardless of
where you happen to be driving in your home town.
And, just like your favorite FM radio station, the MTS signal would fade, get
scratchy or disappear altogether as you reached the edge of town. But the most
important similarity of all was that your favorite radio station had the exclusive
use of the frequency it was broadcasting on throughout the area – as did the
MTS service.
If your favorite radio station broadcasts on 98.7 FM, then you already know that
there’s only one 98.7 FM in your local area. The reason for that is because if
there were more than one station broadcasting on that same channel in the
same geographic area, the two signals would interfere with each other.
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NEW DIRECTIONS IN WIRELESS
Similarly, when an MTS tower would transmit its signals the frequencies that
they were using were locked up throughout the entire area. That meant that only
one person could be talking on an MTS frequency in an entire city – just as if
radio station 98.7 FM locked up the 98.7 FM throughout your home city.
To compound the problem, at one point there were only three channels (two
frequencies per channel – one for sending, one for receiving) allocated to this
service in major cities. This meant that in New York, Chicago, Miami and other
huge cities throughout the country only three people could use the Mobile
Telephone Service simultaneously.
Not 300 or 3000 –
M
T
S
just 3.
You can imagine the problems that caused – because of the backlog of pending
orders, you had to wait and wait for service, and once you finally did get a phone,
you experienced difficulties actually getting on the service.
What was the big Improvement that we might laugh at today?*
*See Buying Vowels
After years of dealing with Alice the Operator on MTS systems we were finally
able to place calls ourselves. A big technical advancement came along and
allowed users to enter the phone number that they were calling and press a
button to “Send” the call to the system that would then process it. This ability to
place the call without operator intervention was a major improvement, so we
renamed the technology that we used for mobile telephone service from MTS
(Mobile Telephone Service) to IMTS (Improved Mobile Telephone Service).
It may not sound very advanced to you now, but this happened way back in
1946, so it was really high-tech back then. First place that IMTS service was
available? St. Louis. (Don’t ask why; nobody seems to know.) However, IMTS
still suffered the same major flaw as MTS: limited capacity.
Why is Advanced better than improved?
In trying to fix the problem of limited capacity, engineers at AT&T took the
advantages of IMTS and expanded the capacity of the system by using the
frequency reuse concept. Incredibly, the concept of frequency reuse was
developed back in 1947. The only problem was that the idea was ahead of the
technology.
There was no way to actually make the system work because it required a high–
ASK THE WIRELESS WIZARD
13
speed method of moving the calls from one cell site to another and technology
simply hadn’t advanced that far yet.
But before we look at how frequency reuse works, let’s understand where the
next acronym in our wireless history comes from. The first wireless phone
system was called MTS, the second one added an “I” (for “Improved” because
you could place the call without the need for an operator) to make it IMTS.
However, terminology changed at about this time. People started abbreviating
the term “telephone” to “phone.” So, what was originally called “MTS” (Mobile
Telephone Service) would probably have been called “MPS” (Mobile Phone
Service) if it had been invented a little later.
So, when AT&T’s Bell Laboratories developed the idea of frequency reuse, they
changed the “I” to an “A” (for “Advanced”) and named the new technology AMPS
(Advanced Mobile Phone Service).
What is the Public Switched Telephone Network
and why do we need it?
Every phone on the planet, wired or wireless,
must somehow be able to connect to any
other phone in order to make them all useful.
After all, how much good would a
wireless phone (or the one on your desk
or kitchen wall) really be if it couldn’t
call to anywhere, or receive a call from
anywhere? Not much, right?
Like a giant water pipe that wraps
around the world – the Public Switched
Telephone Network (PSTN) connects
all of the phone systems in the world.
But, if you want to put water in, or take water out of that giant pipe, you need a
garden hose connected to it. That’s what every wireless and wireline system does
– it takes all of the calls you originate or receive on it and connects it to that
giant water pipe using its own little garden hose. The Private Branch Exchange
(PBX) in your office is, in many ways and certainly in this way, very similar to a
Mobile Telephone Exchange (MTX) that’s used as the brains of a wireless
system.
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NEW DIRECTIONS IN WIRELESS
Keeping this in mind, if you want to make a call to some other phone (put water
into the pipe) or receive a call from some other phone (take water out of the
pipe), your phone needs to be connected to the Public Switched Telephone
Network (PSTN). The PSTN is the common link between all phones, regardless
of whether they are wired or wireless.
3 What makes this mysterious radio stuff work?
To understand phones, pagers, two–way radios and all of the technologies that make them
work, you may want to think about the way radio waves work. Radio waves are the
fundamental gears that make all of these other wheels turn. Without them, nothing could
be sent wirelessly and we would live in a world where the only way you could send
information would be through wires, cable and fiber optics.*
What can The Beach Boys and country lakes teach us about how
radio waves work?
Information, whether it’s in the form of voice, data, video or whatever, can travel
over wires, or over the air – what we call radio waves. In order to understand
radio waves, it helps to be able to picture country lakes and have some
familiarity with the Beach Boys.
Wait a minute … did he say the Beach Boys? Yup… because they were the ones
who sang,
Catch a wave & you’re sittin’ on top of the world
And catching a radio wave is the way to move your information –
voice, data, video or whatever.
To understand this, let’s picture a calm country
lake in the early morning. It’s so still that you can
see your reflection in it. Then, from out of the sky
comes a huge meteor that lands in the middle of
the lake. When it hits the calm surface of the
water, it creates waves that start at the center
of the lake and end at the shore.
Leaves, dust and other items floating
on the lake get carried from the center
of the lake on each wave to the shore.
Just like those leaves and particles of
ASK THE WIRELESS WIZARD
15
*By the way, these are
all good things, and
they all have their
roles to play in our
world.
dust carried on waves of water, information in any form – voice, data or video –
can be carried on radio waves.
Radio waves, you see, are the movement of unseen particles called electrons.
When a force like a meteor drops into the middle of a lake it’s like the force of a
radio signal pushing waves out from its antenna, carrying pieces of information.
And, in its most simple form, the more waves there are, the more leaves – or in
our case information – that can be carried.
Who was Mr. Hertz (not the rental car guy) and why did we
name the measurement of radio frequencies in his honor?
Heinrich Hertz helped us develop the measurement of the number of these
radio waves. He thought that we needed a standard to measure. Today, people in
various places in the world still measure distance differently. Some places use
feet, other use meters, and so on. But time is a constant, uniform benchmark
everywhere, and so he wisely used time as his measurement.
Hertz developed a way to measure the number of radio waves – just like waves
of water – that passed a specified spot in one second of time. He defined a wave
– again, like a wave of water – where the peak of a wave passed any specified
point. From one peak to another peak would indicate one wave, and the distance
between the two peaks represented one wavelength.
peaks of waves
So, if one peak of one wave passed one point in one second of time (the
standard length of time that Hertz decided to use), he referred to that as one
“cycle” of the radio wave. If two waves passed one point in one second of time it
would be defined as two “cycles” of the radio wave.
This measurement, however, was cumbersome to say as “one wave passing one
point in one second of time,” so we shortened it and, in Heinrich Hertz’s honor,
called each of these cycles a “Hertz,”. This was later abbreviated as “Hz.”
But why do i see initials in front of the “Hz” abbreviation and
what do they mean?
As radio gear became more sophisticated we were able to measure, capture and
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NEW DIRECTIONS IN WIRELESS
move electrons at a much faster rate. So, although old Heinrich could never
imagine waves moving faster than a few cycles per second, soon we were
making these waves move at hundreds, thousands, millions and billions of
cycles per second thanks to new, advanced technology.
In order to represent these much faster measurements of cycles, we turned to
the metric system. We now use certain initials before the “Hz” abbreviation to
indicate these faster measurements:
KHz – KiloHertz – Kilo meaning one thousand in the metric system, so this
MHz
GHz
means 1000 waves (cycles) passing one point in one second of time.
– MegaHertz – Mega meaning millions in the metric system, so this means
one million waves (cycles) passing one point in one second of time.
– GigaHertz – Giga meaning billions in the metric system, so this means
one billion waves passing one point in one second of time.
So, putting on our metric math hats, we can realize that there is a direct
correlation between each one of these measurements – that multiplying one by
1000 leads us to the next metric abbreviation upwards:
1 MHz (1 million Hertz) X 1000 = 1 GHz (1 billion Hertz)
Therefore, as an example, 1900 MHz would be the same as 1.9 GHz.
This is generally referred to as the “frequency” on which a service is transmitted
or broadcast. In the wireless world, for example, a very small part of the radio
spectrum between 800 and 900 MHz (eight and nine hundred million cycles per
second, respectively) is used for the original cellular service that so many people
have become familiar with. Therefore, when discussing services in terms of radio
we sometimes refer to cellular in the U.S. as “an 800 MHz service,” or that
cellular service works in the “800 MHz ‘band’.”
Why are there so many different divisions on a spectrum chart
– and what do they all mean?
A spectrum chart can be a mysterious place, so let’s let the Wireless Wizard clear
a few things up.
1. The lowest frequency (same as the number of cycles, or number of Hertz)
was designated for certain services long ago.
2. Also note that as time progressed we were able to make use of higher and
higher frequencies (more waves passing one point in one second of time)
because of more sophisticated technology.
ASK THE WIRELESS WIZARD
17
3. Different services, like the FM radio that’s in your car or the portable phone
that you carry, work better on different frequencies because, like physical
waves, different frequencies of radio waves work better for carrying different
kinds, or amounts, of information.
In the United States, the Federal Communications Commission (FCC) keeps a
vast database of who is using which frequencies in what areas. It’s important to
do this so that two companies don’t try to use the same frequency in the same
place at the same time. That would be like two trains trying to use the same
tracks in the same place at the same time. Bad idea. The two trains would
eventually crash, having interfered with each other’s path.
Interference in the radio world is the same thing. A frequency (one little slice of
the vast, but finite, radio spectrum) can’t have two different users in the same
place at the same time. If one company uses a specific frequency, it cannot be
used by another in the same general geographic area (except if there is prior
agreement between the two companies).
Why are pagers, two–way radios & wireless
phones like traveling on One–Way Streets,
Express Lanes and Interstate Highways?
Radio techniques can be complicated things, but if we view them in the same
fashion as something we understand, like streets and roads, it may become
clearer.
HIGH–SPEED, TWO-WAY TRAFFIC NEEDS A SPECIAL KIND OF ROAD
We can compare devices that work wirelessly to different types of roads, depending on, like
roads, what they’re designed to do.
For example, some roads, like Interstate Highways, are designed to handle lots
of high–speed traffic that travels in both directions at the same time. There’s a
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NEW DIRECTIONS IN WIRELESS
barrier (or a “buffer zone”) between the two sides of the road so that the cars
won’t accidentally bump into each other. One lane is for northbound traffic, one
lane is for southbound traffic. Each side allows traffic to flow unimpeded, but
along the same stretch of road.
Similarly, when we use sophisticated two–way communications devices like
cellular telephones or Personal Communications Service (PCS) phones, we need
two “roads” so that we can talk and listen on the same device at the same time.
This is just like traveling northbound and southbound on the same highway.
The two “roads” that we use are two different “frequencies” that are on the same
stretch of road (the frequency “band” that they use), but are still separated by a
buffer zone between the two roads. When two frequencies are teamed to provide
talking and listening at the same time, we call them a “channel.”
The buffer zone, in this case, is a chunk of spectrum that separates the two
frequencies that we use for talking and listening – or, as we refer to them in the
wireless industry, transmitting and receiving.
When you look at these channels as two sides of an Interstate Highway, you can
view them as one side each for talking and listening, transmitting and receiving
– northbound and southbound. Each has a buffer zone in the middle allowing
traffic to safely flow in two different directions at the same time over the same
stretch of highway.
Now, we all know that it’s impolite to interrupt someone else who is talking. So
you should understand that this is not the intention of providing two
frequencies to form a channel. Rather, the intention is to allow us to enjoy the
convenience of talking and listening without having to take any other action,
such as what’s required to operate our next method.
EXPRESS LANES THAT CHANGE TRAFFIC FLOW
Some roads allow traffic flow in only one direction at a time, but can change direction
when necessary.
Some roads change direction. Like an express lane on a busy highway that’s
designed to let traffic flow southbound in the morning and northbound in the
afternoon to accommodate rush hour traffic, some types of wireless devices
allow us to talk and listen over the same channel, but not at the same time.
You’ve seen how the local policeman uses the radio in their car or on their belt –
ASK THE WIRELESS WIZARD
19
The engineer–types in
the industry call this
traffic pattern “Full
Duplex” – the “du”
prefix coming from
the Latin for “two.”
This is two–way traffic
that only goes in one
direction at a time, so
the engineers refer to
it as “half–duplex.”
they push a button to talk and then release the
button to listen. What they’re actually doing is
conducting a two–way conversation on one
channel (the same stretch of road), but only letting the traffic
flow in one direction at a time. Push the microphone button
and the traffic flows southbound (talking or transmitting).
Release the button and the traffic flows northbound (listening
or receiving). It’s a halfway solution to two–way traffic.
Why would anyone use this half–duplex methodology that
makes you press a button instead of just talking into a phone?
Because it conserves a finite resource: the radio spectrum.
Traffic flows in both directions over one narrower stretch of
road by managing the direction of the flow with the press of a
button.
SOME STREETS ONLY NEED TO LET TRAFFIC FLOW ONE WAY ALL THE TIME
Many streets in local neighborhoods are only one-way; if the traffic flows north, it always
flows north. It doesn’t flow south at the same time, nor does the street’s traffic pattern
change at any time of day. It’s just a plain old one-way street.
Some radio devices, like some streets, only need to let traffic flow in one
direction at a time. The FM radio in your car, the portable radio you carry when
you jog or sit at the pool, even your garage door opener, are all examples of
devices that use the radio spectrum but only have to deliver traffic in one
direction.
Engineers call this
“Simplex” – the “sim”
stemming from the
Latin prefix indicating
“simple” or “only
one way.”
Pagers, too, are good examples of this one-way traffic flow (even though many
of the newer pagers can work in a two–way fashion, most of them are still oneway). They receive information or, in other words, the traffic only flows in one
direction on one side of the road without the need for the direction of that traffic
to change.
%
How can light bulbs and flashlights help us understand the way
that radio signals are transmitted?
Have you ever noticed the difference between turning on a light switch when
you enter a dark room or switching on a flashlight?
The difference is simple, really. The light switch, which activates a bulb, provides
light to the entire area in an indiscriminate pattern. It doesn’t have any one
20
NEW DIRECTIONS IN WIRELESS
direction, so to speak, but rather the light leaves the bulb in all directions at
once. Some radio signals, like the ones for an FM radio station that you listen to
in your car, work the same way.
Other radio signals work more like a flashlight – their beams are electrically
controlled to put all of the power in one specific direction. The flashlight is
designed to cast as much of its light as possible on the spot where it is aimed.
In the world of radio we call the type of radio signal that’s like the light bulb
“omnidirectional” and the radio signal that’s like the flashlight “directional” or
“spot beams.”
There are different applications for these signals, just as there are for light bulbs
and flashlights. When trying to provide radio coverage to a general area, the
omnidirectional pattern works best. When trying to provide coverage to a specific
area, radio engineers would use an antenna that provides a directional pattern.
4 How do wireless systems work, anyway?
What does your favorite FM radio station teach you about the
next advancement in mobile phone technology?
Whether it’s classical, jazz, country, talk format, rap, or rock n’ roll, everyone’s
got a favorite radio station that they listen to as they drive to work or around
town. Of course, one of the real benefits of having a radio in your car is that you
can listen to the same station no matter where you are, as long as you’re within
range of that radio station’s signal.
FM radio stations intentionally broadcast their signals at a high power through
an omnidirectional antenna so that it covers as many parts of the market area as
possible. But what happens if you drive to another city? Your favorite radio
station won’t reach there because if it did there couldn’t be another radio station
using the same frequency in the other city. Here’s an example:
Let’s say you live in Los Angeles and that your favorite station is 98.7 FM. No matter where
in L.A. you live, whether it’s at the beach, near downtown, or even as far away as Palm
Springs (about 100 miles) you can listen to radio station 98.7 FM.
If you go as far away as San Diego (200 miles) or San Francisco (400 miles), however, you
wouldn’t be able to hear the Los Angeles station that broadcasts on 98.7 because it won’t
reach that far. That’s because the radio station’s power is intentionally kept low enough to
avoid interfering with the station that uses 98.7 in San Diego and San Francisco.
ASK THE WIRELESS WIZARD
21
You see, by limiting the power output of the station that uses 98.7 in Los
Angeles so that it only covers the Los Angeles metropolitan area, you can then
reuse 98.7 in another part of California.
If you now understand why radio stations don’t blast their signal at a power
level that broadcasts all over the United States, you also understand the key
fundamental technique behind what makes wireless phone systems work –
. The ability to reuse spectrum (where these
frequencies come from) is the fundamental concept that gives wireless systems
the ability to continually expand their capacity and coverage.
frequency reuse
So keeping the transmission area small is what makes wireless
phone systems work?
Exactly. Every large geographic area is divided into many – sometimes hundreds
– of smaller geographic areas. Each one of these smaller areas is referred to as a
“cell” and has it’s own radio equipment and antennas. They each use an assigned
portion of the spectrum – their own frequencies – to conduct telephone
conversations wirelessly.
i don’t get it … how do you increase capacity by decreasing the
size of cells?
In its simplest form, if one cell is using a frequency for its business, that same
frequency can’t be used again in the cells adjacent to it. Remember in our
previous example, the FM radio station frequency, 98.7, couldn’t be used in
another town that’s too close to the source of that signal in your home town,
because the two signals would interfere with each other. The same principle
applies here. Avoiding interference is the name of the game.
In fact, the ability to continually expand is dependent on keeping the size of the
area that the signal is transmitted to as small as possible. It works like this:
± The smaller each one of the “cells” in a system, the more cells that can be put
in the same geographic area.
± The more cells that can be put in the same geographic area, the more that a
specific frequency can be reused over and over again.
± The more times a frequency can be reused in a geographic area, the more
conversations that can be held at the same time.
± More capacity for simultaneous conversations means more people can be on
their wireless phones at the same time.
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NEW DIRECTIONS IN WIRELESS
± More people talking on their wireless phones at the same time means more
revenue for the operators that build the systems.
± Therefore, building more cell sites is an investment that operators are willing
to make, presuming that there will be enough conversations (referred to as
“traffic” in wireless-speak) to amortize the cost of the cell.
What does hand-off mean, and how often does it happen?
As a wireless phone user travels through a system that’s designed to carry their
calls, the phone and the system must continuously talk to each other in the
background so that the system knows where the phone is.
When a call is in progress and the user (well, the phone, actually) is moving
through the system, the calls have to be handled by all of the cells through
which the user travels. (Remember, the large geographic area is divided up into
all those cells so that we can employ frequency reuse to get more efficient use of
the radio spectrum.)
However, as we learned earlier on, cells that are next to each other (called
“adjacent cells” in industry language) can’t use the same frequencies because
they will interfere with each other. Therefore, the calls must change frequency as
they move from cell to cell. When a wireless phone user moves from one cell to
another and the call is shifted to a different frequency to avoid interference, we
refer to that process as call “hand–off.”
What really happens when i turn on my phone?
When you turn on your phone a conversation happens in the background
between your phone and the system. During this conversation, the system has a
question-and-answer session with your phone, asking it to send some critical
information so that it can verify that your phone is a legitimate user.
The critical information that the system asks for is the Mobile Identification
Number (MIN), which we know more commonly as the phone’s phone number.
The system also asks for the Electronic Serial Number (ESN), a unique number
that is assigned at the factory to every phone that is produced. Like fingerprints,
ASK THE WIRELESS WIZARD
23
*This illegal alteration
is referred to as
“cloning.” It’s a big
problem in today’s
industry, costing
carriers about
$1 billion/year.
Thieves steal your
MIN and ESN by
listening to analog
phone signals (it
won’t happen on
digital phones, so the
problem is decreasing
through time) and
then entering the
information into
another phone’s chip.
Then, when they turn
on the illegal phone, it
fools the system into
thinking that it’s your
phone because it
sends out all the
legitimate information. There are many
tools and software
solutions in the
industry designed to
fight the problem.
there are never two ESNs that are identical, unless they have been
illegally altered.*
The information transmits back-and-forth between your phone
and the system. The system checks this information against the
its database and confirms that you are a user in good standing.
Finally, the system directs your phone to turn on the light or
indicator telling you that you’ve got service. On some phones this
indicator is a blinking light, on others a green LED on the screen
and on others the name of the company that supplies the service
appears in the screen of the phone.
How does the system know where i am?
Whoa. Slow down there. Let’s just say that there’s a conversation
going on in the background between your phone and the wireless
system that you never hear. That conversation does a lot of work, but the
process starts when you first press the “Power” button. Here’s a rundown of who
says what to whom:
Phone
System
Phone
System
Phone
System
System
Phone
24
When you press the “Power” button to turn your phone on, the phone says, “Hey, I’m
Joe’s phone … just want to let you know that I’m on the air and may need a channel
to make a call. Oh, and just in case anybody is looking for me, I’m in cell number 123.”
Hold on a minute. I don’t know who you are. Before I let you make any calls – or
send any calls to you – I need to verify that you’re a legitimate user. You know, that
you are registered on this system, that your calls aren’t restricted, that you pay your
bills … that kind of thing.
OK, I understand that. What kind of information do you want?
Send me your Mobile Identification Number (MIN – more commonly referred to as
the phone number) and the Electronic Serial Number (ESN – every phone on the
planet has its own unique serial number – presuming that it hasn’t been “cloned,” or
stolen from someone else’s phone. More on that later.)
OK, here you go… I’m sending my MIN and ESN.
Got it. Hang on a second.
At this point, the system checks through its database of registered users. If it finds that
phone number, it checks to see if the ESN matches it. If it does, it goes to the next step. If not,
it won’t allow the process to go any further.
You’re a registered user and I’m giving you permission to make or receive calls on
the system. You can tell because I’ve lit up the light on your phone that indicates
“Ready.” (On some phones it’s a green flashing light, on some phones it’s a word that
says “Ready” in the display and still others use a different indication… check the
manual for your phone if you’re not sure.)
Thanks. I’m ready.
NEW DIRECTIONS IN WIRELESS
How does it let me place a call?
When you turn on your phone, the phone communicates with the nearest cell
site. The cell site then tells the system where to find you if a call comes in for
you. It keeps a register of who is where, and as you move through the system
the register is constantly updated. In many systems this is referred to as the
“Home Location Register,” or “HLR.”
When a call comes in for your phone the system will page you in the last place
that it has you registered. If you’ve turned off your phone the system will send
the caller directly to voice mail (or to a message saying that you’re out of range
or that your phone is turned off). If the phone is on, the system knows where
you are – or, more accurately, what cell you are in – and sends the call there.
How did the “Send” button get such a silly name?
You might notice that wireless phones don’t provide “dial tone” when you pick
up the phone. That’s because, unlike a wired phone, there’s no cradle to hang up
the phone. So there’s really no way to tell when the phone is being put to your
ear. Rather than generating a tone all the time, designers of the first wireless
systems decided that it would be easier to not have any dial tone at all.
Instead, they designed the system so that you could enter the phone number
that you wanted to call and then press a button to send the call from the phone
to the cell site, and then on from the cell site into the system. As the button was
used to “send” the call from the phone into the system, it was labeled “Send.”
It’s really an anachronism today, because “Send” (and it’s counterpart that
terminates the call, “End”) are both being phased out in favor of more logical
terms. Depending on the phone that you use, the buttons that initiate and
terminate a call might be called, respectively, “OK” and “End,” “OK and “Cancel,”
”Start and Stop,” or one of many other combinations. Some manufacturers have
dispensed with words altogether and simply use an icon of a phone off-hook as
the symbol to begin the call and an icon of the phone back in its cradle (onhook) as the indicator for the button that terminates the connection.
*Interesting, isn’t it,
how we still call that
ever-present tone on
our landline phones
“dial” tone when we
haven’t used “dials” to
make phone calls in
years. It’s an expression
that has been around
for a very long time
and will likely take
just as long to disappear, even though
it is completely
inappropriate at this
point. It might
ultimately become
“ready” tone or “call”
tone, but for the time
being we’ll still be
calling it “dial” tone.
What does the Send button actually do?
When you press the ”Send” button, you are telling the phone to prompt the
system to place a call to the number you’ve entered.
Send
More conversations between the phone and system are required to place a call,
ASK THE WIRELESS WIZARD
25
but the big one has already occurred, so these are shorter. The user enters a
phone number by using the keypad on the phone or bringing it up from the
speed dial directory, then presses the magical “Send” button. Here’s what
happens:
*The PSTN is the
network of all the
telephone company
”brains” (well, they’re
really computers) that
connects all of the
calls from one part of
the world to the other.
The telephone
equipment on the
PSTN maintains large
databases of numbers
so that each phone
call can be directed to
its proper destination.
The equipment
doesn’t have the
entire list of every
phone number in the
world, just a kind of
map to get there. It
works in the same
way that a road map
does. It doesn’t have
every single address
in the world on it, but
it does have all of the
roads that will get you
to that address.
± The phone sends the number to the nearest cell site.
± The system uses a portion of the radio spectrum dedicated to “overhead”
(anything but voice conversations) called a “control channel.”
± The cell site relays that phone number to the brains of the wireless system,
which then communicates with the Public Switched Telephone Network*
(PSTN).
± When the PSTN finds the phone at the number that the wireless user has
called, it routes the call to that number.
± If the phone line is available, it sends a signal back to the MTX, which relays
that news to your phone.
± As soon as the phone starts to ring at the number you’ve called, you hear the
ringing on your wireless phone.
How does a call get to me?
The process is reversed:
± A call from another phone enters the wireless system through the Public
Switched Telephone Network (PSTN).
± From there, the system’s brain (the switch, but we’ll get into that later)
recognizes which phone to send the call to, checks the location register to see
within which cell you were most recently located.
± The system then sends a signal to the cell that you were in to “page” your
phone.
± Presuming that you’re still there the phone answers the page, indicating to
the system that the call should be sent to that cell and, from there, on to your
phone.
± When your phone rings (or vibrates, or plays music, or flashes lights, or
whatever you have yours set up to do), you press the button that activates the
call (Send, OK, Start, whatever) and the call is completed to your phone.
Why won’t the phone work in some places? Can’t companies just
put up another tower when they need to?
There are already almost 60,000 wireless towers scattered throughout the
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NEW DIRECTIONS IN WIRELESS
United States. Hundreds more are being added every day.* New carriers have to
match the coverage of the existing ones, and established carriers are constantly
increasing the capacity and trying to improve the coverage of their own systems.
As a result, the demand for new tower sites grows dramatically every day.
If this pace continued there would be a tower on just about every street corner.
And, while that might be a wonderful goal for the tower builders and antenna
providers of the world, it’s not a very pleasing prospect from an aesthetic
standpoint. As a result, many communities have implemented moratoria against
the construction of new towers, forcing wireless companies to “co-locate” their
facilities on each other’s towers.
It’s a real irony in the business – everyone wants their wireless phone to work in
their home, driveway and garage, but nobody wants to have a tower in their
back yard.
Other things affect coverage, too.
TERRAIN
Both hills and valleys interfere with radio signals. Rolling hills can be tough to
deal with, but imagine what happens when you drive to the other side of a
mountain. If you were listening to your favorite FM radio station in your car,
that signal would fade or disappear. The same thing happens to a signal from a
wireless phone system.
BUILDINGS
Tall concrete or steel buildings can be tough on radio signals. And buildings in
the south with reflective tinting on the windows to keep out the sun are
particularly tough on wireless phone systems because that tinting also does a
pretty good job of keeping out radio signals.
FOLIAGE
All those beautiful trees can soak up radio signals like a sponge. Wireless phone
systems can have significantly different coverage in different seasons unless they
are engineered understanding that in advance.
WATER
Large bodies of water, like lakes or very wide rivers, do something different to
radio signals – they don’t exactly interfere with them, but rather reflect them,
causing a problem called “skipping” which sometimes lets radio signals travel
further than they are intended to, thus interfering with other systems.
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27
*Between mid-1997
and mid-1998, the
last period for which
we have statistics,
19,000 towers were
added
5 What are the components of a wireless system?
What’s in a cell site?
First, a little background. When the engineers at AT&T developed the concept of
frequency reuse more than fifty years ago, they needed a graphic representation
of the way that the system would work. As they sketched out the workings of the
system it became clear that it looked very much like a honeycomb. And in a
honeycomb, each of the tiny compartments of a hexagonal shape is referred to
as a “cell.” (You didn’t think that a marketing person came up with such an
amorphous, non–descriptive name like “cellular,” did you?)
A single site within a wireless system is typically referred to as a “cell site”
despite the fact that many systems are now referred to as “PCS” systems instead
of “cellular” systems. Each one of these sites – and there are typically hundreds
of them in a metropolitan area – contains certain common pieces of equipment
to help it do its job.
TOWERS
*See On existing
structures, below
Freestanding
Sometimes there just isn’t a tall building where you need one. If there’s no place
to mount an antenna for a cell site on an existing building* companies will have
to build a freestanding structure – a tower – where they need coverage.
Monopole
These are the most popular types of freestanding towers because they blend the
easiest with the surrounding environment. They can be painted virtually any
color and are narrow enough to almost disappear against the background of the
sky or hillside. Typically, they are constructed in prefabricated sections so that
they can be easily stacked and bolted together in the field.
Steel beam (Lattice or Guyed)
These are the ones that you’re probably most familiar with, although the ones
you’ve seen may not have been developed for wireless phone systems. These
towers, in fact, are built to be stronger, with wider bases, so that they can be
taller or hold more equipment. They look like a diagonal grid of steel beams
standing on four legs and, if tall enough, are painted in alternating sections of
orange & white. If they’re very tall, they’ll require a flashing light at the top, too.
On existing structures
Not every cell site requires a freestanding tower. Sometimes, like in dense urban
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NEW DIRECTIONS IN WIRELESS
areas with lots of buildings, there’s no room to build a tower, or the cost would
be prohibitive. So instead, cellular antennas are mounted on existing structures.
Rooftops
The most popular place, but building owners are getting smart to the idea that
wireless companies will pay lots of money to find a site in a good location, so
this can be expensive even if it’s less costly than building a freestanding tower.
Utility poles
Utility poles have already faced zoning battles and are already in place
in most neighborhoods. New mounting technology allows the wireless
company to put a cap on top of a utility pole that will hold wireless
equipment.
“Stealth” towers
Because of the uproar in some communities about the proliferation of towers,
frequently operators will attempt to disguise towers so that there are no protests
from the local residents. The industry refers to these as “stealth” towers and they
can be disguised to look like: Church steeples · Trees that aren’t really trees ·
Shopping center signs · Lampposts
SHELTERS AND SELF-CONTAINED EQUIPMENT BOXES
All of the radio gear that makes this magic work is contained in boxes typically
found at the base of a cell site. If the cell site is actually located in an existing
building the cabinets that hold this gear might be found somewhere inside the
building, but close enough so that there isn’t a lot of signal loss through the
cable that stretches from the antennas to the electronic equipment.
Many new sites, especially those in “stealth” locations, require self-contained
equipment cabinets. Frequently these sites are in the middle of parking lots
where there isn’t a shelter of some kind to hold and hide the equipment. These
self–contained cabinets have all of the electronics gear that’s needed, plus they
also have their own climate control and backup power supplies in case the
utility’s power to which they’re connected is interrupted.
AUXILIARY POWER REQUIREMENTS AND AIR CONDITIONING
Every cell site must have standby power. If the utility’s power is interrupted, two
major things would otherwise happen:
First, the cell site would be off the air, meaning that anyone trying to make,
ASK THE WIRELESS WIZARD
29
receive or continue a call in that cell site would not be able to do so. Established
calls would be dropped (a very bad thing for the company’s reputation and the
most common complaint among wireless phone users) and people trying to
make calls would receive a “system busy” audible indication.
Second, the cell site’s electronic gear generates a lot of heat, especially because
it’s in an enclosed area. So, without constant air conditioning – which would be
interrupted without backup power – there might be severe damage to the
sensitive electronic components.
CONNECTIONS TO THE REST OF THE SYSTEM
Each of the cells in the system must somehow connect to each other so that a
call can continue without interruption from one end of the system to the other,
as a phone user travels through it.
These signals can be handled in one of two ways: either (1) over telephone lines
that the wireless company leases from the local telephone company or (2) via
microwave dishes connecting the various towers to each other and ultimately to
the main hub of the system, referred to as the “switch.”
Is there really such a thing as a switch? Why do I hear it
referred to as the MTX, MTSO or MSC? What does it do?
The switch is the brain and the heart of the wireless system all rolled up into one
big computer. Although it is referred to universally as “the switch,” it is
frequently referred to by a number of different acronyms, all of which are used
interchangeably:
MTX
Mobile Telephone Exchange (just like a PBX, which is a Private Branch
Exchange – more commonly known as a company’s private telephone
system, usually recognizable by the switchboard that is typically found
at the receptionist’s area)
MTSO Mobile Telephone Switching Office (there’s that “switch” word)
MSC Mobile System Controller (usually heard in places outside the United
States).
In a wireless system all the individual cell sites are connected to the “switch.”
They may not all be directly connected – some may be In addition, each of the
cells has to be connected to this central point in order to receive the commands
necessary to handle all of these transactions, collect the billing information and
much more.
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NEW DIRECTIONS IN WIRELESS
The switch is typically located in a very secure building to prevent vandalism
and it’s not uncommon for it to be co-located (in the same place) as the carrier’s
main office in that market.
Each switch, however, can only handle a certain load of work. So when the
system starts getting too large, it may need the addition of another switch to
share the load. This can happen when there are too many cells for one switch to
keep track of or too many users for the switch to coordinate
Sometimes a second (or third, depending on the size of the system) switch
might be added because the carrier wants to be on the safe side and keep two
switches running in the event that one of them fails. We call this “redundancy”
because all of the switches maintain a full database of users, call information
and other key data. If any of the other switches fails or has to be taken offline
for routine maintenance the redundant switch can carry the load until the
others are back to full operating capacity.
OK, wireless is cool, but the world is shifting to the internet.
is that going to change the wireless business, too?
You can count on it. In fact, it’s already happening. Wireless devices are
becoming onramps to the Internet. There are several groups that are
developing standards for all manufacturers to meet, but the most advanced group is the Wireless Applications Protocol Forum (WAPF).
By following the standards that WAPF is developing, soon, every phone
that’s sold will contain a miniature Web browser, allowing the user to tap
into a variety of databases. Imagine getting directions, checking on movie
times, securing a seat reservation and paying for tickets all through a few
quick keystrokes on your wireless phone or pager.
Nothin’
but Net.
The key thing to remember is that the Internet works on a different type
of technology than the old style telephone services to which we’ve grown
accustomed. “Internet Protocol” or “IP” is the name of this new technology and
it is far more efficient than the older, circuit-switched type of connection.*
You’ve probably heard or read about the race to provide the fastest type of access
to the Internet from both home and office. All of the “wired” technologies such
as cable modems, Digital Subscriber Lines (DSL), Integrated Services Digital
Network (ISDN) and others get plenty of publicity. But wireless technologies are
poised to make a tremendous impact.
ASK THE WIRELESS WIZARD
31
*The difference
between “IP” and
Circuit-switched
connections is
explained in the next
chapter.
Companies like Teligent and Winstar offer services to office buildings that can be
accessed through tiny (12 inch) antennas on the roof of a building. Internet
access at speeds higher than any current wired connection are attainable at a
fraction of the cost of getting wired-access services from the local telephone
company.
Teledesic, a joint venture of cellular bzillionaire and pioneer Craig McCaw and
Microsoft founder Bill Gates (gzillionaire supreme), intends to launch a
constellation of 288 satellites at low altitude, speeding around the earth’s surface
to bring hyperspeed Internet access to anyone, anywhere, anytime.
How can shipping a car from New York to Los Angeles teach us
the difference between a circuit switched and packet data
connection?
FIRST – WHAT ARE CIRCUIT SWITCHED AND PACKET CONNECTIONS?
There are two fundamentally different ways that telephone calls – wired or
wireless – can be conducted. We can classify the transmission of the voice and/or
data from one point to another – whether it’s between people or computers – as
either “circuit switched” or “packet” connections.
In short, circuit switched is the technology we’ve been using for 100 years.
It’s old and inefficient. Packet connections are the way that the Internet works
and, because it’s so efficient, is the way that telephone companies want their
systems to work, too.
When you place a phone call to Mom [You do call your mother regularly, don’t
you?], a connection exists between the two phones for as long as the two of you
are on that call. Until you hang up, nobody else can make use of that circuit that
is connecting you. That’s a solid, reliable way to make a connection, but it’s
inefficient because there will be plenty of times that there are moments of
silence during a conversation. So it’s kind of like having a big oil pipeline and
every once in a while the flow of oil gets shut off. You still have to pay to build
and maintain the pipeline, but you’re not getting any use out of it.
On the other hand, when you send an email over the Internet, or request a Web
page to be downloaded to your computer, you’re using a packet connection
(presuming you haven’t made a phone call over a modem to connect to the
Internet, but that’s too confusing for now).
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NEW DIRECTIONS IN WIRELESS
That means that your email is broken up into several different packages, or
“packets” and sent via whatever routes are available over the Internet. When all
of the packets reach the other end they are reassembled back into their original
form and, voilà, your message arrives at its destination just the way you sent it.
LET’S SHIP A CAR FROM NEW YORK TO L.A. TO ILLUSTRATE THE DIFFERENCE
Pretend for a moment that you needed to ship a car from NY to LA. You might
call FedEx and get a price quote, which would be extremely high. The FedEx
people (unfailingly polite, in my experience) would tell you that if you shipped a
car with them that you’d be commandeering the use of an entire truck to pick it
up, drive it across country and then unload it in LA.
But if you ask for an alternative, the FedEx people might tell you to take the car
apart, label every part and include a list of all the parts – and how to reassemble
them – with every individual part. Then, each time that there is a FedEx truck in
your neighborhood it would come by your house and see what parts you have
remaining to ship. The driver would check to see how much space is on the
truck and find one or more parts that would fit in that space.
As each of the parts get picked up, the complete list of parts and reassembly
instructions would accompany it. When all of the parts arrived in LA (which
you’d know because you’d be constantly checking off the arriving parts against
your list) you would reassemble it according to the instructions. At that point,
you would have your entire car, exactly the way that it was before you took it
apart, in the place you wanted.
By putting individual parts on various FedEx trucks instead of commandeering
an entire truck for your car to be shipped you are making much more efficient
use of the space on the truck. As a result, FedEx would charge you just a tiny
fraction of the total cost to ship each part and the final cost would still be much
less than using an entire truck to ship the car without taking it apart.
Shipping the car in its entirety is like a circuit switched connection. For as long
as the car is on the FedEx truck, you essentially own that truck. That’s why they
charge you so much money to do it that way. But shipping it in pieces is like a
packet connection, because by taking it apart you are allowing the carrier (in
this case, FedEx) to make more efficient use of their space. Sending voice and
data that way makes very efficient use of bandwidth and spectrum because you
can send a small packet over whatever avenue is available at that moment.
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33
So, you can ship your car in one piece – expensive and inefficient, like a circuit
switched connection, or in multiple pieces – less expensive and more efficient,
like a packet connection.
What’s the difference between analog, CDMA & TDMA technologies?
The three major technologies that wireless companies use today are analog
(represented by the AMPS standard), TDMA (represented by both the GSM
standard and the IS–136 standard) and CDMA (represented by the CDMAone
and IS–95 standards).
Each of them has their proponents and critics. None of the technologies is going
to “win” and kill off the others because they each have some advantages over
the others. There’s room for all of them, but if you consider their functional
differences you’ll gain greater understanding of how they work.
Why is the difference between them like going to three
different cocktail parties?
You and your friend decide to go party–hopping one night because you’ve heard
about three different parties all being held on the same block. There’s the analog
party, the time division multiple access (TDMA) party and the code division
multiple access (CDMA) party.
AT THE
Analog PARTY
When you first enter the analog party it’s quiet. Many couples are waiting on
line in front of a door and there’s a sign over the door that says “Conversations
in this room only.” You and your friend wait your turn in a long line. Inside the
room are two people carrying on a conversation. They chat for a while, pause,
chat some more and finally complete their conversation. When they are done,
they leave the room and the next couple on line enters the room.
You and your friend figure you’ll never get to carry on a conversation, so you
decide to leave and try the TDMA party.
AT THE
TDMA
PARTY
When you get to this party there’s a similar line in front of the door that says
“Conversations in this room only.” The line is shorter and appears to be moving
more quickly. When your turn arrives the two of you enter the room and find
five other couples in there. Each couple appears to be speaking for a brief period
and then allowing the next couple in the sequence to speak.
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NEW DIRECTIONS IN WIRELESS
You and your friend are couple number three because the couple that left just
before you walked in had the number three slot, which you just took over.
Couple number one speaks for a minute and then stops. Then couple number
two speaks for a minute and stops. Then it’s time for the third couple – that’s
you – to talk for a minute. You do and then relinquish your rights to couple
number four.
This continues until all six couples have had a minute to speak. Then couple
number one speaks again for a minute, then couple number two and so on. Each
couple has been assigned a “time slot.” (Yours is number three.)
Now, let’s reduce the time that each couple can speak from one
minute to a smaller increment of time. If we can divide a day
into 24 hours and an hour into 60 minutes and a minute
into 60 seconds, why can’t we divide a second into 60 or
more different parts? We can – and each one of these 60
“time slots” is equally divided amongst the six couples.
Each couple now will speak ten times in each second, for
one–sixtieth of a second each time. It’s the same as speaking for
one minute and then allowing the next couple to speak, but it’s
just done in smaller increments.
S
What we’ve done here is to divide time into various “slots”
and assign each one to a conversation. That’s why we call
this technology (remember, it’s not a standard) Time Division Multiple Access.
We divide time to give more than one conversation access to it.
AT THE
CDMA
PARTY
When you and your friend arrive at this party there is yet another room with a
sign over the door that says, “Conversations in this room only.” The line at that
door is quite short, and moving very quickly. You wait your turn and enter the
room in just a few moments.
Upon entering the room you see ten couples in the room – and they’re all
speaking at the same time. However, each couple is speaking a different
language. You and your friend are assigned to speak Chinese by the controller in
that room. When you begin speaking, you realize that although there are many
other couples in the room speaking at the same time as you are, it doesn’t matter
because each couple only speaks and understands their assigned language.
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35
In other words, each conversation is coded – only the person on the other end
can understand the language that is spoken. No matter how many people you
put in that room each conversation can be kept separated from the others as
long as there is another code (or language, in this case) to speak.
We call this technology Code Division Multiple Access because that’s exactly
what it does – it assigns a code to each conversation and allows more than one
couple to carry on a conversation in that room (on the radio channel).
—shhh
—shh
Quiet noise at the
CDMA party
shh–
—zzz
shhh—
Critics of CDMA say that eventually there will be so many conversations being
held in that room that the noise from all of them – referred to in radio terms as
the “ambient noise level” will drown out all of the conversations.
Advocates of CDMA say that the ambient noise level will never drown out all of
the other conversations because each time that another couple is added to the
room every other couple lowers the volume of their own discussion. The room,
therefore, is constantly judging the number of couples in it and making
adjustments as to how loud each conversation should be.
This may oversimplify the differences between analog, TDMA and CDMA
technologies, but it’s an easy way to relate to, and remember them.
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NEW DIRECTIONS IN WIRELESS
6 What’s the difference between services,
standards & technologies? Why is it important?
Apples & oranges, cars & airplanes, birds & bees and GSM, TDMA
& CDMA all have one thing in common: They are all comparisons of
things that are related, but are really different. What are GSM, TDMA
and CDMA, you ask? I’m glad you did, because most people in the
industry don’t really understand the relationship between them.
How can you win a bet with your boss and prove that everyone
refers to standards, iNCORRECTLY, as GSM, TDMA and CDMA?
Apples and oranges are both fruits, but are different. Cars and airplanes are both
transportation mechanisms, but they are different. Birds and bees, well, they
may both fly, but they are certainly different, too. The same thing applies to
GSM, TDMA and CDMA – they are all related to the wireless industry, but they
are different, too.
Here’s what the Wizard means by that, and how you can win a bet with your
boss about it: The three major categories that you can define things by in the
wireless industry are:
Services · Standards · Technologies
SERVICES
Services are a collection of capabilities that are packaged and sold to the public,
such as:
Cellular
PCS (Personal Communications Services)
Paging
Two–Way Radio
STANDARDS
Standards are collections of specifications about how equipment is supposed to
work. When scientific and engineering groups get together to create standards,
they typically have representatives on the committees from many of the major
manufacturers. These standards are then adhered to by all manufacturers so that
everyone’s equipment can work on everyone else’s systems. That’s why you can
use a phone from Motorola, Ericsson, Nokia, or anybody else on a cellular or
PCS system regardless of who makes the stuff that makes the system work.
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37
POPULAR SERVICES
Cellular
(800 MHz – U.S.)
PCS
SOME OF THE STANDARDS THEY CAN USE
AMPS (Advanced Mobile Phone Service)
NAMPS (Narrowband Advanced Mobile Phone
Service)
IS-54 (Interim Standard 54)
NMT 450 (Nordic Mobile Telephone at 450 MHz)
GSM (Global System for Mobile Communications)
IS-136 (Interim Standard 136, a modified version of
IS-54, designed to accommodate digital technology)
IS-95 (Interim Standard 95, which is also referred to
by the brand name of “cdmaONE” by Qualcomm,
the developers of commercialized CDMA
technology). Although the standard itself is “open”
the technology that drives it (CDMA) is not; anyone
building wireless equipment using some CDMA
technology will have to pay royalties to Qualcomm.
Paging
POCSAG (Post Office Code Standardization Advisory
Group – an “open” standard that anyone can build
equipment for without paying royalties)
FLEX (A proprietary standard developed by Motorola
that has become the “de facto” worldwide standard.
Other makers of paging gear must pay royalties to
Motorola if they make equipment that conforms to
this standard.)
It’s important to note that any given service can work on more than one
Standard (though not at the same time) and at virtually any frequency that the
FCC – or any other regulatory body in foreign countries – makes available for its
use. So, Cellular might use the AMPS standard, as it does in the United States,
but it could also use the GSM standard, as it does in Europe.
You could call this relationship of Services to Standards a “one–to–many”
relationship, i.e., one Service (Cellular) can use many different Standards
(AMPS, GSM, etc.)
TECHNOLOGIES ARE WHAT MAKE THE VARIOUS STANDARDS WORK
Every standard currently in operation uses one technology – a “one–to–one”
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NEW DIRECTIONS IN WIRELESS
relationship. Future standards may employ the use of two or more technologies
in a combination to get the most use of the spectrum. In wireless industry
terminology, we refer to this better use of the radio spectrum resource as
“spectral efficiency.”
SOME POPULAR STANDARDS
AMPS
TECHNOLOGY IT USES
Analog
(Advanced Mobile Phone Service)
GSM
TDMA
(Global System for Mobile Communications)
IS-136
IS-95
CdmaONE
TDMA
CDMA
CDMA
So why is it so incorrect that everyone in the wireless
industry refers to GSM, TDMA and CDMA as standards?
As you can see from the tables shown above, GSM is a standard and both TDMA
and CDMA are technologies. In fact, the GSM standard uses TDMA technology
to get its job done. Therefore, putting GSM, TDMA and CDMA into one
category as “standards” is incorrect. The industry, however, has gotten so
accustomed to referring to the IS–136 standard as “TDMA” and the IS–95
standard as “CDMA” that they are accepted terms. They are incorrect, but they
are accepted.
Why isn’t there a worldwide standard – or at least a
Talkin bout my Third …
worldwide frequency that all wireless phones work on?
G
G
G
That’s what we’re working towards. In fact, you’ll probably read a lot about a
new standard that the industry refers to as “3G.” That’s short for the third
generation of wireless technology. The industry’s widely recognized view is that
analog technology, based standards such as AMPS, is ancient history. What we
need now is something advanced, digital and with enormous capacity. But, in
addition to all that, it would be ideal to find one frequency that is clear on a
worldwide basis. That way we could have one phone, on one standard, which
could be used all over the world.
That’s not going to happen, though, because different countries have already
allocated various parts of the spectrum for different services. Some of the
spectrum that is available in the United States, as an example, is reserved for
…
eneration
military uses in Europe. Spectrum that’s available in Europe isn’t available in
Japan. And so on.
ASK THE WIRELESS WIZARD
…
39
The solution to this comes from an advance in technology. Manufacturers are
creating phones that work on a multitude of different frequencies. We call them
“multiband” phones. By handling all of these different parts of the spectrum the
phone can scan through all of the spectrum that’s assigned to wireless phones
worldwide and lock onto the proper one in every country. Manufacturers are
calling this the “World Phone.”
7 What makes the wireless industry tick?
if the industry is already so successful, where will all the
future users come from?
Finland: Where
wireless is ubiquitous.
It is also widespread.
While it’s true that the industry has been very successful, the United States has
only half the penetration rate (percent of the population using wireless phones)
that Finland does. How could that be?
It’s a matter of time, really. Finland and the rest of Scandinavian were the first
places to get commercial cellular service. They’ve had years longer than the U.S.
population to adopt wireless as a primary form of communication. In fact,
young Scandinavians have stated in surveys that they are likely to choose a
wireless phone as their only phone. They won’t even be getting a wired phone in
their homes.
But back in the USA, there is a huge market that’s yet untapped. If 25% of
people already have a wireless phone, then 75% of the population doesn’t. Even
if we eliminate some of the population due to age or income, that still leaves a
huge upside potential.
i don’t get it – why is coverage so lousy in some places? Can’t
the wireless companies just put up another tower site where
they need one?
If only they could. As you may remember from page 25, one of the great ironies
of the wireless business is that everyone that uses a phone wants to have perfect
coverage in their house, driveway and garage. But nobody wants to have a tower
in their back yard. It’s the
syndrome – “Not In My Back Yard.”
NIMBY
And, as we mentioned previously, in some parts of the country the government
has gotten into the act, too, because of the proliferation of towers. In many
places you will find a moratorium on the building of any new towers, forcing the
operators in that area to “co-locate” with each other. That means that if Carrier X
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NEW DIRECTIONS IN WIRELESS
owns a tower someplace where Carrier Y doesn’t have good coverage, Carrier Y
will rent space on Carrier X’s tower instead of building a duplicate of it just for
their own system. It makes a lot more sense that way, but the disadvantage is
that eventually all of the carriers will have the same coverage areas.
There’s a huge business, in fact, in building “stealth” tower sites – things that
either aren’t what they seem to be (like phony trees) to things that serve dual
purposes (church steeples, shopping center signs) so that the aesthetics of the
local neighborhood aren’t blighted by too many towers.
As of the end of 1998, there were more than 50,000 cell sites in the United
States. With more carriers coming on line, and existing carriers always trying to
expand their coverage and capacity by adding more sites, you can expect that the
battle over towers – and the move towards co-location and stealthy tower sites –
will accelerate.
Why does the government get involved in regulating some of
this stuff?
Wherever there’s money to be made using a public resource, sooner or later the
government is going to want to put their fingerprints on it. In this case there are
three different levels of government regulation – federal, state and local – that
impact the wireless industry.
FEDERAL REGULATION
There are two agencies that watch over the wireless industry for two completely
different reasons. First, the Federal Communications Commissions (FCC),
develops the criteria for issuing a license to an operator, allowing them to use
the radio spectrum for purposes of providing wireless telephone services.
In the past, licenses were issued almost indiscriminately. Whenever a company
asked for more spectrum they got it. But that ended when the government
realized how valuable spectrum was becoming. At that point they began issuing
licenses for new spectrum on an as-needed basis, requiring the party that
requested the spectrum to demonstrate that there was a need for it because the
public could not be served if it wasn’t granted to them.
Licenses for the original cellular telephone service were issued in the early
1980s, often after lengthy and hotly contested court battles about who should
receive them. When the FCC recognized that lengthy delays weren’t in the public
interest, they began issuing them in a lottery. Submit an application and you
ASK THE WIRELESS WIZARD
41
could become the lucky winner of a cellular telephone license, often worth
millions of dollars.
* There’s a great
debate about why
television and radio
broadcasters should
get their spectrum for
free while cellular and
PCS companies have
had to pay for theirs.
It’s unfair, but the way
the world works is
that the National
Association of
Broadcasters (NAB)
has an incredibly
powerful lobby in
Washington.
Essentially, if a
politician ever wants
his face to appear on
TV again he wouldn’t
be caught asking the
broadcasters to pay
for the spectrum that
they’ve been getting
free for 50 years.
In the end, however, greed took over. The government started auctioning the
rights to use the radio spectrum. Auctions were unpopular ideas, but
nonetheless have been the way that spectrum for Personal Communications
Services (PCS) spectrum have been issued. For purposes of two–way wireless
communications this is still how the FCC issues spectrum.*
The FCC also oversees “interconnection” issues, which are those complex
dealings that occur between wireless operators and the local telephone
companies that connect their calls into the Public Switched Telephone Network
(PSTN). The government looks over the shoulder of the local telcos to make
sure that interconnection rates are reasonable and that they adhere to all prior
agreements.
The Federal Aviation Administration is also involved in the
wireless industry. They want to make sure that wireless
companies don’t build tall tower sites that are too close to
flight patterns at airports. In most cases this doesn’t really matter to the
wireless industry because tower sites are not nearly as high as those built for
other purposes (like FM radio broadcasting), but they still look over each
application to ensure that it meets their standards.
STATE REGULATION
Many states used to monitor “Grade of Service,” which is a fancy way of saying
what percentage of calls that are attempted at the busiest time of day are blocked
from completion. Most times, calls that are blocked are the result of there not
being a sufficient number of channels in the cell that the caller is trying to place
the call from.
In today’s more competitive environment, however, this is no longer necessary.
If a subscriber’s calls are being blocked too frequently there are alternatives. The
open market takes over and competition pushes all carriers to design better,
more robust systems.
LOCAL REGULATION
For the most part, local regulation focuses on tower site construction and
location. Municipalities want to be sure that wireless companies comply with
zoning laws, and in some cases have started taxing wireless carriers.
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Local concerns also include environmental issues. Aside
from aesthetic appeal, there is a great concern about
ensuring the safety of rare species of birds, plants and insects.
Carriers planning to build sites in certain sensitive areas may
be required to file environmental impact statements which
often necessitate the employment of botanists, zoologists,
seismologists and about any other kind of “ist” you can
imagine.
Naturalist
What is churn, and why is it so important for
wireless companies to avoid it?
Nobody likes to lose business. Wireless companies like it a lot
less than others do for a number of reasons, but the very first
one is (obviously) money. Wireless companies lose a tremendous amount of
money when a customer leaves their system because it costs a tremendous
amount of money to get that subscriber to sign up in the first place. The costs
for adding a subscriber can be broken down into the following areas:
MARKETING COSTS
This is what carriers pay for all of the advertising, salespeople, brochures and
anything else that stimulates activity.
SUBSIDIZATION
Carriers typically underwrite the cost of phones so that they cost less to
subscribers, making them more appealing to buy and thus, hopefully,
stimulating more demand.
INTERNAL COSTS
Customer support staff, office space, electricity, coffee (hey, gotta keep
those customer support reps awake, right?) and other personnel.
The Wizard’s beverage
of choice: Cup o’ Joe
in Styrofoam.
INFRASTRUCTURE COSTS
Huh? Why would it cost money to add infrastructure, you might ask. The
reason is simple: As new subscribers are added to a wireless system the system
requires additional channels to support them, which means adding more radios
to cell sites, adding more cell sites for yet more capacity, adding more microwave
links, trunk lines, connections to the PSTN, etc., etc. The cost can be staggering.
In fact, think about this:
During the first 14 years of cellular service in the United States, about $50 billion
ASK THE WIRELESS WIZARD
43
was invested in infrastructure. When that’s divided by the total number of
subscribers (about 65 million at the end of 1998), you get an incremental cost of
roughly $800 per new subscriber.
Add that $800 per subscriber for infrastructure to the cost of marketing,
subsidization and internal costs, etc., and you’ve got a major expense for every
new subscriber that signs up. So what happens when a subscriber starts service
and then cancels just a few months later? Simple, the carrier loses money.
Contract
That’s why it is becoming so common for carriers to require subscribers to sign a
contract for a year or more before they’ll give them a phone at a highly reduced
cost. They want to be sure that they’ll recover the money they’ve invested in that
subscriber.
New subscribers have already made a commitment – with their wallets. Here’s
why: Some of the newer “PCS” carriers, however, boast in their advertising that
they don’t require any monthly contracts. Subscribers have the option, they say,
of leaving whenever they want, making the potential subscriber feel comfortable
because they haven’t had to make a commitment to a long-term agreement.
There’s just one problem: subscribers that purchase phones to work on new,
digital “PCS” systems have already signed a contract with their wallets.
*Lots of wireless
companies offer
special rate plans that
give subscribers free
usage at night and/or
on weekends, when
the system is very
lightly loaded. So,
although the total
number of minutes
used by new
subscribers may be as
high, or in some cases
higher, than minutes
used by longer-term
subscribers, those
minutes may not
always be billable.
You see, phones that are sold by carriers operating 100% digital systems (what
the industry refers to as “true PCS”) are often coded at the factories that make
them (at the request of the carrier that’s buying them, of course) so that the
phones will only work on their systems. Even if the subscriber takes that phone
to another carrier that uses the same technical standards, chances are that the
phone won’t work there.
There’s another reason why keeping customers longer is becoming so important.
It’s because the average revenue per subscriber continues to decrease as more
subscribers are added. It’s just a simple matter of most people that have the
greatest need for wireless phones have already purchased one, so the new
subscribers that are added don’t use their phones for quite as many billable*
minutes.
if some countries already have 25%–50% penetration, from where
is the future growth for the wireless industry going to come?
While we in the United States have become accustomed (some would say
spoiled, or even jaded) to having telephones everywhere, that’s simply not the
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NEW DIRECTIONS IN WIRELESS
case worldwide. It may shock you to know that more than half the people in the
world have never used a telephone. The number of phones per person, called
“tele-density” in industry language, is remarkably low in other parts of the
world. In some places as little as 2% of the households have phones in their
homes.
In countries like India, China and parts of South America it would take years, if
not decades, to bury wire all throughout the major cities to provide phone
service. Wireless technology provides a faster, and in many cases cheaper,
solution to the need for telephone services. Wireless systems that integrate
portable and fixed products are already on the market.
A “fixed” product is defined as a standard telephone, fax machine or answering
machine that plugs into an outlet,* but is connected to the Public Switched
Telephone Network (PSTN) via wireless. An antenna would be mounted on the
side or the roof of the home (or business) and pointed at the nearest cell site.
The signal would be sent to and from the cell site using standard wireless
technology, but once it is received by the antenna at the home it is fed into the
wiring that runs throughout the house. The user can then plug a standard
phone into any phone outlet in the house and get service that is virtually
identical to wired (also called “landline”) service.
So, despite the fact that some countries have an extremely high penetration rate
of wireless phones into the population, the future potential growth of wireless
technology, sales of equipment and provision of support services is extremely
positive. There are still tens of millions of people that don’t carry phones in their
pockets and hundreds of millions that don’t have access to any phone at all.
i’ve heard some people talking about “3G.” What does that mean?
Should it be important to me?
As you learned on page 37, 3G stands for Third Generation – the third
generation of wireless phone equipment. The first generation was considered to
be the original, analog cellular phones. The second generation is the digital
cellular phones that we are accustomed to seeing today that have advanced
features on them like Caller ID, built–in paging and voice mail and so on.
The next generation of wireless gear, 3G, will have many more features. These
features are closely tied to the rise of the Internet and to the demand for more
multimedia-type services. When manufacturers around the world agree on
ASK THE WIRELESS WIZARD
45
*This outlet is
commonly called a
“phone jack,” and in
the United States it is
referred to by the
technical term
bestowed on it –
“RJ–11 jack.”
standards for 3G there will be an entirely new segment of services
offered on the phones that work on those systems.
Users of 3G phones will be able to:
± browse the Internet’s World Wide Web
± retrieve email
± get advanced information services such as stock quotes and sports news
± get weather updates
± get real–time traffic information, customized to the their exact location
In addition, there will be services that will provide entertainment, like listening
to remote–broadcast radio stations, full-color displays of still photos and
eventually even video, all on a standard-sized handset.
—I see by my wireless information device that it’s time to buy low and sell high.
8 What’s next? Is my wireless phone ever going
to become obsolete? Will newer technologies
take over?
It’s unlikely that your wireless phone will become obsolete. You
might choose to get a new one because of all the advanced features
that you could take advantage of, but the one that you’re carrying
now will work just fine for many years to come.
You can look at it as the difference between black-and-white
vs. color TV. The old black-and-white TV you have out in the
garage somewhere will work just fine even on the most
advanced cable channels. But in order to get the benefits of seeing movies,
weather radar displays, sports events and other broadcasts as they were meant
to be seen, you’d need to upgrade to a color TV set.
i hear a lot about satellite services. Does the wireless industry
use them now?
Satellites are already effectively used for a variety of applications around the
world. The broadcast and receiving of TV signals, aeronautical and naval
navigation and communications, exploration of deep space and much more.
Satellites can also be used for two–way wireless communications, but there are
some drawbacks.
Satellite service, by its very nature, works off transmission and receiving points
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NEW DIRECTIONS IN WIRELESS
(the satellites) that are at least hundreds, and in many cases thousands,
of miles away. When using a phone that works off satellites instead of a
ground-based system (such as a standard cellular or PCS system) you’d
need to have a clear path between the phone and the satellite, so you
couldn’t be underground, in an office building or on the inside of a ship.
However, there are some places in the world where traditional cellular
and PCS systems will never be built because there just isn’t enough
demand there to amortize the cost of a system. Some places are just too remote
– deserts, the North Pole, the middle of the Atlantic Ocean – and can’t be
covered by any type of service other than something that would be based on a
satellite that’s moving over your head.
There are many different systems being planned for potential customers to take
advantage of, but the first one to launch – and the one that has consequently
gotten the most fanfare is Iridium. This is a constellation of 66 satellites that are
in a choreographed dance in orbit over your head in such a way that at least one
satellite is always within range of your handheld phone. When you make a call,
the phone connects directly to the nearest satellite, which relays the call to a
ground station and then connects it into the worldwide public telephone
network.
Iridium, however, has also become the industry’s first failure – there simply
weren’t enough customers willing to pay thousands of dollars for a phone that’s
twice as large as a standard wireless phone and then several dollars per minute
once they owned a phone. The company declared bankruptcy in August, 1999.
Has anyone thought about providing Internet access via
wireless? is that what LMDS is all about?
Wireless access to the Internet is what many in the industry consider to be the
next frontier. Giving people full-time, always-on
access to the Internet eliminates the need for dial-up
connections and a nearby phone outlet. Instead, you
could set up an antenna on your laptop, desktop or
rooftop and connect your computers into the
Internet using wireless systems that are referred to
as “Broadband Wireless” by the industry.
Local Multipoint Distribution Service (LMDS) is a
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47
slightly different type of service, but will provide wireless Internet access as one
of its portfolio of offerings. Businesses , and eventually homes, would subscribe
to a service that would provide local and long distance telephone service,
Internet access and probably even cable television all through the same antenna.
There are several companies licensed to offer LMDS services already competing
in each major market in the United States. In the industry they are also referred
to as Competitive Local Exchange Carriers (CLECs). Two of the more prominent
CLECs are Teligent and Winstar.
9 The Wizard’s Apprentice
Wow. There’s a lot of ground for you to cover, but I think you did a pretty good
job. Now you’ll feel better when you’re reading a trade journal, listening in on a
lunchtime discussion between engineering-types, or just reading whatever
memos come your way.
It’s an exciting wireless world. The phone or pager that you carry today doesn’t
look much like the one that most people carried ten years ago – and the one that
you carry ten years from now will look much more like a wireless voice and data
appliance than what we can imagine now.
You may not have found the answer to everything in this book, but I’ll bet you
know more now than you did before you read it. And that’s good, because the
more you know, the more you can relate our technology and its benefits to your
family, friends and neighbors. So spread the word –
you can now consider yourself a …
∑ireless
∑izard’s
Apprentice!
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NEW DIRECTIONS IN WIRELESS
Glossary
WIRELESS INDUSTRY TERMS
1.5-way paging Refers to guaranteed message receipt or advanced messaging, ensuring subscribers
receive messages sent when they’re out of range, but users cannot send text pages. Two-way paging
allows users to send and receive. Coined by SkyTel Communications Inc.
1.7-way paging A paging service that offers more than guaranteed messaging but not as much as full
two-way paging. The subscriber has limited response messaging, such as canned messages, rather than
the ability to create responses.
1996 Telecommunications Act Legislation designed to spur competition among wireless and wireline
carriers. Signed into law by President Clinton Feb. 8, 1996.
3G The next generation of wireless technology beyond personal communications services. The World
Administrative Radio Conference assigned 230 megahertz of spectrum at 2 GHz for multimedia 3G
networks. These networks must be able to transmit wireless data at 144 kilobits per second at mobile
user speeds, 384 kbps at pedestrian user speeds and 2 megabits per second in fixed locations. The
International Telecommunication Union seeks to coordinate 3G standards through its International
Mobile Telecommunications-2000 project. In early July, the ITU received 10 proposals for 3G systems
and is currently holding a series of meetings to evaluate the specifications.
5ESS A registered trademark name for Lucent Technologies Inc.’s electronic switching system.
802.11 The Institute of Electrical and Electronics Engineers standard for wireless local area network
interoperability.
A
A/B Switch: Allows a user to change their wireless phone from one carrier to another through the
keypad (older phones actually had a physical switch to do the same thing).
A-Band cellular In the U.S. cellular duopoly, the alternative carrier to the regional Bell operating
company’s cellular subsidiary.
Abbreviated Dialing: A feature on wireless phones where you enter just one or two digits from the
keypad and then initiate the call. The phone searches its speed dial directory and associates the
entire number with the two-digit speed dial position you’ve entered.
Access Charge: The fixed part of the monthly fee that carriers charge to subscribers. Sometimes this
charge includes a certain amount of minutes of usage.
Access fee A special fee that local phone companies are allowed to charge customers for the right to
connect with the local phone network. Cellular subscribers contribute to access fees and pay a
federal 3 percent telephone excise tax.
Activation Fee: A charge imposed by carriers for the processing and activation of wireless phone
service.
Adaptive array antennas A type of advanced smart antenna technology that continually monitors a
received signal and dynamically adapts signal patterns to optimize wireless system performance. The
arrays use signal processing algorithms to adapt to user movement, changes in the radio-frequency
environment and multipath and co channel interference.
Adaptive Power Control: Technique employed by wireless infrastructure systems that lowers the
power of a signal in a cell site whenever the site detects that the user’s phone is close to the source
of the signal. This saves power in the phone, too, but the cell site tells the phone to lower its power,
thus saving battery life.
Adjacent channel interference Signal impairment to one frequency due to presence of another signal
on a nearby frequency.
Affiliate Companies that assist larger carriers with building out a nationwide network; the affiliate may
use the primary carrier’s brand name, network operations, customer service or other facilities.
Agent: A company, retail store or other establishment that has a relationship with one or more carriers
that guarantees them a commission, and sometimes a residual payment, for each wireless phone
subscriber that they sign up through their facility. These establishments typically are allowed to
display the carrier’s logo, but cannot claim any direct employment or contractual relationship with
them.
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AIN (advanced intelligent network) Introduced by AT&T Network Systems in 1991. Enables service
providers to define, test and introduce new multimedia messaging, PCS and cell routing.
Air interface The standard operating system of a wireless network; technologies include AMPS, TDMA,
CDMA and GSM.
Airtime Actual time spent using a wireless phone.
A-key A secret number issued to a cellular phone that is used in conjunction with a subscriber’s shared
secret data information for authentication
Alphanumeric A display, message or readout that contains both letters and numbers. Synonymous
with text paging or messaging.
AMPS (advanced mobile phone service) The analog cellular standard.
AMTA (American Mobile Telecommunications Association) A Washington, D.C.-based trade group
representing specialized mobile radio operators.
Analog: The original form of cellular service, launched in October, 1983 in the U.S. (and earlier
elsewhere). This service uses a waveform transmission instead of the zeros and ones that a digital
system uses. It is more prone to interference, static, eavesdropping and cloning than digital systems,
but is still deployed in many parts of the world where the advanced technology (and higher cost) of
digital systems is not deemed necessary.
ANSI (American National Standards Institute) A U.S. standards group.
Antenna: A metallic rod that typically extends from a wireless phone or cell site from which the
electrical signal that is transmitted emanates from. Cell sites might have different antennas for
transmitting and receiving. Wireless phones might have either small, fixed antennas (called “stubbies”)
or retractable antennas. Newer phone models have “intennas,” which are antennas that are not visible
to the user because they are housed completely inside the phone unit.
APCO (Association of Public-Safety Communications Officials-International) Trade group
headquartered in South Daytona, Fla., representing law enforcement, fire, emergency services and
other public-safety agency dispatchers and communications employees.
ARIB (Association of Radio Industries and Businesses) The Japanese standards-setting
organization.
ARPU (average revenue per unit) One indicator of a wireless business’ operating performance. ARPU
measures the average monthly revenue generated for each customer unit, such as a cellular phone or
pager, that a carrier has in operation. Severely declining ARPU typically is a negative sign that may
indicate a carrier is adding too many low-revenue generating customers to its rolls.
ASIC (application-specific integrated circuit) An integrated circuit tailored for a particular piece of
electronic equipment. It is intended for sale to only one company and typically developed to meet
that company’s design objectives for a particular application. Not to be confused with an application
specific standard processor, which, like an ASIC, is designed for use in a particular piece of equipment
but is intended for sale to multiple companies.
ATM (asynchronous transfer mode) A high-speed, high-bandwidth transmission technology.
ATM (automatic teller machine) Referring to financial applications using smart cards.
Attenuation: A loss of signal strength caused by distance (“free-space loss”) or other physical factors
like terrain, buildings and foliage.
Authentication center A protected database that stores and processes secret keys required to
authenticate wireless telephones
Authentication: A method used by some systems to validate that a user is legitimate. It typically
involves some form of encryption/decryption scheme on both ends of the transmission between the
phone and the system.
Authentication A fraud prevention technology that takes a number of values—including a 26-character
handset identifier or A-Key, not sent over the air—to create a shared secret value used to verify a
user’s authenticity.
Auto PC An in-vehicle combination AM/FM radio, Windows CE-based computer, compact disc and
CD-ROM player, wireless phone and navigational system. The units are about the size of a typical car
stereo.
AVL (automatic vehicle location) Combining a location-sensing device (such as a GPS receiver) with a
wireless communications link to provide a home office or dispatcher with the location of a vehicle or
mobile asset (such as a trailer or heavy machinery).
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NEW DIRECTIONS IN WIRELESS
B
Bag Phone: An older type of phone, more technically referred to as a transportable, that provides the
advantages of an A/C adaptor for unlimited power, an external antenna for better coverage and
greater output that creates a stronger signal than a portable phone can offer.
Bandwidth A relative range of frequencies that can carry a signal without distortion on a transmission
medium. Sometimes referred to as a “pipe.”
Base Station Controller: The part of the wireless system’s infrastructure that controls one or multiple
cell sites’ radio signals, thus reducing the load on the switch. It can be viewed as a form of distributed
processing.
Base Transceiver Station: (BTS): The portion of the wireless system’s infrastructure that is responsible
for sending and receiving the actual radio signals over the airwaves. This device takes radio signals
from subscribers’ phones and sends them over leased telephone lines or microwave signals to the
switch.
B-Band cellular In the U.S. cellular duopoly, the regional Bell operating company’s cellular subsidiary.
B-CDMA (broadband code division multiple access) A technology developed by InterDigital
Communications Corp.
Bent pipe technology Satellite technology to transmit calls from one point on Earth to a satellite and
back down to another point.
Bidding credits Discount sometimes given to small businesses in FCC spectrum auctions.
Big LEO Low-earth orbit satellite system that will offer voice and data services; e.g., Iridium, Globalstar.
Blocked Calls: An uncompleted call made from a wireless phone. Calls can be blocked for numerous
reasons, but this typically refers to an instance where there are insufficient channels in a cell to
handle the load of calls required. When a call is attempted within that cell and no channels are
available, the call is “blocked” and a fast busy signal is heard by the subscriber.
Bluetooth The code name for a new wireless technology being developed by Ericsson Inc., Intel Corp.,
Nokia Corp. and Toshiba. The technology enables data connections between electronic devices such
as desktop computers, wireless phones, electronic organizers and printers in the 2.4 GHz range.
Bluetooth would replace cable or infrared connections for such devices.
Broadband PCS Synonymous with personal communications services created in the A- through F-Block
auctions and used for voice and data.
Broadband Using a wide-bandwidth channel for voice, data and/or video services.
BTA (basic trading area) Usually composed of several contiguous counties. BTAs are a service area
designed by Rand McNally and adopted by the FCC. There are 493 BTAs in the United States.
Build-to-suit The process by which independent firms find and build antenna sites to meet a carrier’s
specifications.
Bundling Grouping various telecommunications services—wireline and/or wireless—as a package to
increase the appeal to potential customers and reduce advertising, marketing and other expenses
associated with delivering multiple services. For example, a bundled package could include long
distance, cellular, Internet and paging services.
C
CAD (computer-aided dispatch) Computer systems to help dispatch personnel and vehicles,
commonly used by public-safety agencies.
CALEA (Communications Assistance to Law Enforcement Act) A 1994 law granting law
enforcement agencies the ability to wiretap new digital networks and requiring wireless and wireline
carriers to enable eavesdropping equipment use in digital networks.
Call Diversion: The term used for call forwarding on a GSM system.
Call Forwarding: A feature on both wired and wireless phones that sends calls to another number from
that which was originally called. A typical example would be to forward the calls from your office
phone to your wireless phone when you are away from your office.
Call Timers: A feature on wireless phones that shows the user how long the current call has progressed,
or how many minutes have been used cumulatively since the last time the “Total Call Timer” feature
has been reset.
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51
Caller ID An enhanced feature that displays a caller’s phone number on the wireless handset.
Calling party pays This service bills the originator of a call to a wireless device rather than the receiver
and is more common in other countries than in the United States. However, many U.S. carriers are
pushing for calling party pays, since it would probably increase minutes of use.
Cap code A pager’s unique electronic identification number on the back of the device
CDMA (code division multiple access) A spread spectrum air interface technology used in some
digital cellular, personal communications services and other wireless networks.
cdma2000 A third-generation wireless technology proposal submitted to the International
Telecommunication Union, which is based on the IS-95, or cdmaOne, standard.
cdmaOne The IS-95 CDMA standard developed by Qualcomm Inc.; a word coined by the CDMA
Development Group.
CDPD (cellular digital packet data) An enhanced system overlay for transmitting and receiving data
over cellular networks.
Cell site The location where the wireless antenna and network communications equipment is placed.
Cell Splitting: The process of creating more coverage and capacity in a geographic area by having more
than one cell cover the same area that a single cell originally did. Each cell then covers a smaller area,
with lover power, and thus offers the ability to reuse frequencies more times in a larger geographic
coverage area such as a city or MTA.
Cell: A geographic area within a wireless system that is covered by the signal sent and received by the
transmitter and receiver equipment located within that area. Typically referred to as a “cell site,”
these are represented by hexagonal shapes by engineers when planning systems. That shape was
originally derived from the honeycomb of bees, within which each single unit is referred to as a cell.
Cellemetry Brand name for Cellemetry LLC’s telemetry service, which uses the cellular network to
carry data messaging used for remote services such as utility meter reading, vending machine status
and vehicle or trailer tracking.
Cellular: The name given to the original concept of dividing a large geographic area into smaller
coverage areas called cells. Each cell handles calls on different channels and communicates with the
central processing unit, called a switch, to facilitate the handing-off of calls from one cell to another
as a user moves through the system. Cellular is currently used in hundreds of countries worldwide
and boasts more than 200 million subscribers.
Channel: Two radio frequencies, one used for sending and the other for receiving.
Chapter 11 The section of the federal Bankruptcy Code enabling distressed, but not necessarily
insolvent, companies to seek protection from creditors while they reorganize their finances. The
proceedings are governed by a bankruptcy court judge who must approve any plan of reorganization.
Creditors can be represented in the proceedings and present alternative reorganization plans.
Chapter 7 The section of the federal Bankruptcy Code governing liquidation of insolvent companies in
order to pay their creditors.
Charge back The funds a carrier will “charge back” to an agent or dealer if a customer discontinues
service shortly after buying the product.
Chip set A combination of two or more integrated circuits on one module.
Churn A measure of the number of subscribers who leave or switch to another carrier’s service.
Citizen Alert Program Program in which residents of a community patrol streets and school areas
with wireless phones and notify police of suspicious or illegal activity.
ClassLink A program of the CTIA Foundation providing wireless phones to schools for teacher use and
student Internet access.
CLEC (competitive local exchange carrier) A new entrant providing local wireline phone service.
Click-box bidding A method of bidding for FCC spectrum licenses in which the participant does not
enter a bid amount but simply clicks on the computer screen to enter an amount shown. The method
was first introduced in the auction of upper channel 800 MHz licenses in the fall of 1997.
Clone A wireless phone programmed with stolen or duplicated electronic serial and mobile
identification numbers.
CMRS (commercial mobile radio service) An FCC designation for any carrier or licensee whose
wireless network is connected to the public switched telephone network and/or is operated for
profit.
Co-branding The use of two or more different brand names on a single product, such as wireless
phones bearing the name and logo of both the manufacturer and wireless carrier.
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NEW DIRECTIONS IN WIRELESS
Collocation Placement of multiple antennas at a common physical site to reduce environmental
impact and real estate costs and speed zoning approvals and net work deployment. Collocation can
be affected by competitive and interference factors. Some companies act as brokers, arranging for
sites and coordinating several carriers’ antennas at a single site.
COLT (cell site on light truck) A mobile site on a vehicle placed at a location to fill in or increase
coverage.
Components Semiconductors and smaller elements used in handsets and infrastructure equipment.
Content services Paging service, beyond telephone number alerts, that include news and sports
headlines, personalized stock quotes, driving directions, restaurant reviews and information
contained on Internet sites.
Control channel A logic channel carrying network information rather than the actual voice or data
messages transmitted over the network.
Cost Recovery Reimbursement to CMRS providers of both recurring and nonrecurring costs associated
with any services, operation, administration or maintenance of wireless E911 service. Costs include,
but are not limited to, the costs of design, development, upgrades, equipment, software and other
expenses associated with the implementation of wireless E911 service.
Covered SMR A subset of specialized mobile radio operators subject to a particular set of regulations.
A definition developed in December 1997 during the implementation of E911 regulations encompasses
operators whose networks use intelligent switching capabilities and offer seamless hand-off to
customers. An earlier, broader definition, still applicable in other contexts, encompasses operators
that provided two-way, real-time voice services across geographic license areas in the 800 MHz and
900 MHz bands.
COW (cell site on wheels) A mobile site placed at a location to fill in or increase coverage.
CPE (consumer premise equipment) Telephones, PBXs and other communications devices located in
the home or office.
CPNI (customer proprietary network information) The carrier’s data about a specific customer’s
service and usage. The FCC restricts CPNI use in marketing, banning win-back efforts specifically
aimed at high-usage customers who have quit a network.
Cracker Slang term for someone who breaks an encrypted computer code or circuitry.
Crosstalk: Interference in a wireless communications system that stems from other conversations in
nearby cells using the same channel.
CTIA (Cellular Telecommunications Industry Association) A trade group representing cellular, PCS
and enhanced specialized mobile radio carriers.
Customer acquisition cost The average cost to a carrier of signing up an individual subscriber. Some of
the factors included in the cost are handset subsidies, marketing, advertising and promotions.
D
D-AMPS (digital AMPS) Used by Ericsson Inc. to describe IS-136 time division multiple access
technology.
DCMA (dynamic channel multicarrier architecture) A technology developed by ComSpace Corp.
used for specialized mobile radio networks that can configure the number and bandwidth of voice
and data channels based on a carrier’s requirements.
DCS 1800 (digital cellular system) A global system for mobile communications-based PCS network
used outside of the U.S.
De minimus Having such minimal impact as to not influence the matter at hand. Costs of providing a
service, for instance, may be so low that the party requesting the service sees them as de minimus
and an invalid reason for not offering a service.
Dead spot: An area within a wireless communications system where there is no coverage. This can occur
because an cell site cannot be located close enough to the area without coverage, or because two
signals on the same channel interfere with each other, causing them to “phase out” the other signal.
DECT (digital European cordless telephone) Used as a cordless phone and wireless office phone
system in Europe.
DEMS (digital electronic message service) The FCC wants to relocate this service from 18 to 24 GHz.
Digital: The newest form of wireless communications that takes all voice transmissions and converts
them to computer language (zeros and ones, or “binary” language) and then reconstructs them into
ASK THE WIRELESS WIZARD
53
the original voice format at the other end. More secure than its original sibling, analog, and also
relatively impervious to static or fading signals.
Disaggregation The splitting of a spectrum license into two or more licenses of fewer frequencies.
DISCO II FCC proceeding on domestic-international satellite service consolidation.
Downlink The portion of a telecommunications path from a satellite to the ground. Also referred to as
the reverse link.
Drive test A method of taking signal strength measurements in a cellular coverage area.
Driver distraction A key concern of transportation and law enforcement agencies, wireless carriers
and other entities, driver distraction is a diversion of attention caused by many factors. Factors can
include changing a compact disc or cassette tape, tuning a broadcast radio dial, eating or drinking or
talking on cellular phones. The wireless industry has launched a consumer education campaign to
emphasize safe cellular use while driving.
Dropped Call: A wireless call that is unintentionally disconnected due to a system problem, lack of
channel availability or dead spot in coverage.
DSP (digital signal processor) A specialized microprocessor that performs mathematical operations
on a data stream in real time to produce a second (modified) data stream.
DTV (digital television) The next generation of video and audio technology for TV broadcasters.
Often synonymous with high-definition television or HDTV. According to the 1996
Telecommunications Act, broadcasters can offer “ancillary and supplementary services” such as
paging and data in addition to video programming.
Dual band Describes a handset that works on 800 MHz cellular and 1900 MHz PCS frequencies.
Dual mode Describes a handset that works on both analog and digital networks.
Dual Tone Multi Frequency (DTMF): The sounds made by a phone’s keypad when a button is pressed.
Each button emits a sound that is actually the combination of two specific sounds in order to
minimize the possibility of an incorrect signal being received by the equipment listening to the press
of the buttons.
E
E911 (enhanced 911) 911 service becomes E911 when automatic number identification and automatic
location information is provided to the 911 operator.
EA license (economic area license) Geographically defined licenses based on 176 “economic areas”
delineated by the Bureau of Economic Analysis at the U.S. Department of Commerce. EAs can be
grouped into 52 larger “major economic areas” or 12 “regional economic area groupings.”
ECO test (effective competitive opportunities test) Developed to determine whether U.S. carriers
enjoy effective competition in a foreign carrier’s market before granting U.S. market access to that
foreign carrier. Following the Basic Telecom Agreement signed by World Trade Organization members
in February, 1997, the FCC decided not to apply the ECO test to WTO members.
EDACS (enhanced digital access communications system) A private radio or specialized mobile
radio network designed by Ericsson Inc.
Eighth floor The eighth floor of the FCC headquarters at 1919 M St., Washington, D.C., where the
commissioners’ offices are located. Commonly used to refer collectively to the commissioners. May
become obsolete when the commission relocates to The Portals.
Electronic assistant Generic term for telecommunications access systems based on voice-activation
or voice-response technology, enabling the user to dial phone numbers or send and receive
information such as voice messages or other content. Systems may be network based, such as
Wildfire Communications Inc.’s Wildfire, or offered via a service bureau, such as General Magic Inc.’s
Portico or Motorola Inc.’s planned Myosphere.
Encryption The process of “scrambling” a message such as a digital phone signal to prevent it from
being read by unauthorized parties.
Equal Access Allows long-distance carriers the opportunity to bid for access to local carrier’s
customer’s LD subscription.
ERMES (European radio messaging system) A paging system used in Europe and other parts of the
world.
ESMR (enhanced specialized mobile radio) Digital SMR networks, usually referring to Nextel
Communications Inc., which provide dispatch, voice, messaging and data services.
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NEW DIRECTIONS IN WIRELESS
ESN (electronic serial number) The unique identification number embedded in a wireless phone by
the manufacturer. Each time a call is placed, the ESN is automatically transmitted to the base station
so the wireless carrier’s mobile switching office can check the call’s validity. The ESN cannot be
altered in the field. The ESN differs from the mobile identification number, which is the wireless
carrier’s identifier for a phone in the network. MINs and ESNs can be electronically checked to help
prevent fraud.
ETSI (European Telecommunications Standards Institute) A standards-setting body in Europe.
Ex parte Statements, meetings or filings that are made outside of an official comment-and-replay
period. They must be reported and a summary of them made available in the public record.
F
FAC Certified frequency advisory committee, also known as a frequency coordinator.
Fault-tolerant A method of making a network system or a computer resistant to software errors,
hardware problems or power failures.
FCC (Federal Communications Commission) The federal agency responsible for commercial and
private spectrum management.
Feature Group D Local exchange carrier network service that, among other things, lets public-safety
dispatch offices receive a 10-digit data stream, including the full callback number, alongside wireless
911 calls. Offered as a way by which wireless carriers can meet FCC enhanced 911 rules and dispatch
offices can overcome their current bandwidth limits.
FHMA (frequency hopping multiple access) A digital technology used in Geotek Communications
Inc.’s specialized mobile radio network.
Flash memory A component used for memory that can retain information without power.
Flash ROM A class of Electrically Alterable Programmable Read Only Memory (EAPROM), the contents
of which can be altered in the field, normally without disassembly of the product containing the
memory. Maintains data in absence of power.
FNPRM (further notice of proposed rule making) A document issued by the FCC to spur
additional comment on a future commission action.
FLEX A Motorola Inc.-licensed protocol that gives carriers more capacity on their networks and faster
transmission times. Also refers to the FLEX family of protocols: FLEX, InFLEXion and ReFLEX.
Foliage attenuation Reductions in signal strength or quality due to signal absorption by trees or
foliage obstructions in the signal’s line-of-sight path. For example, 800 MHz systems are seldom
deployed in forested areas. Pine needles-nearly the same length as 800 MHz antennas-can negatively
affect signal reception in that band.
Forward looking An action that ignores the past, particularly previous investment. Often used
regarding FCC efforts to set interconnection terms; its forward-looking price-setting method ignored
phone companies’ historic network costs and was struck down by a federal appeals court.
Frame Relay Wideband, packet-based interface used to transmit bursts of data over a wide-area
network. Seldom used for voice.
Frequency reuse The ability of specific channels assigned to a single cell to be used again in another
cell, when there is enough distance between the two cells to prevent co-channel interference from
affecting service quality. The technique enables a cellular system to increase capacity with a limited
number of channels.
FRS (Family Radio Service) A very low power, short range two-way radio service in the 460 MHz
band.
Full-Duplex: The radio term applied to transmissions such as telephone calls that allow talking and
listening at the same time by using two frequencies to create one channel. Each frequency is used
solely for either transmitting or receiving.
FWA (fixed wireless access) Also known as wireless local loop.
G
Gateway Ground-based link to a mobile satellite service network.
Geosynchronous Maintaining a fixed orbit, about 24,000 miles above the Earth.
Geostationary orbit satellite system A communications system with satellites in geosynchronous
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55
orbits 22,300 miles above the Earth. These satellites appear stationary because they move at the
same rate as the Earth’s rotation.
Gigahertz (GHz): One billion radio waves, or cycles, per second. Equal to one thousand Megahertz.
GLONASS (global navigation system) A Russian satellite location technology similar to global
positioning system.
GMPCS (global mobile personal communications services) A term that refers to future mobile
satellite systems that will provide wireless phone service anywhere in the world.
GPS (global positioning system) A series of 24 geosynchronous satellites that continuously transmit
their position. Used in personal tracking, navigation and automatic vehicle location technologies.
Gray market: May refer to a place where a carrier bought a product from another carrier, not direct
from a vendor or the vendor’s distribution channel. The exact location of the seller/buyer is unknown
to the manufacturer.
GSM (global system for mobile communications) A digital cellular or PCS network used throughout
the world.
GSM-Plus An enhanced version of global system for mobile communications technology that will be
developed to meet IMT-2000 capabilities.
GSM-R Global system for mobile communications for railway networks. GSM-R uses standard base
station and switching infrastructure to provide fast data transmission for railways.
GUI (graphical user interface) A computing term referring to an operating system or environment
that displays options on the screen as graphical symbols, icons or photographs.
H
Hacker A person or group that gains access to secured computer networks for pleasure or challenge,
sometimes to steal information or to sabotage the system.
Half-Duplex: The radio term applied to transmissions which allow two-way communications over a
single frequency through the use of a push-to-talk button that opens and closes the communication
pathway over that frequency.
Handheld personal computer A palmtop device or personal digital assistant that can wirelessly
access e-mail, paging messages and the Internet/Intranets.
Handoff The process occurring when a wireless network automatically switches a mobile call to an
adjacent cell site.
Hands-free A feature for mobile phones that allows the driver to use their car phone without lifting or
holding the handset to their ear
HDML (handheld device markup language) Written to allow Inter net access from wireless devices
such as handheld personal computers and smart phones. Derived from hypertext markup language.
One version of HDML is Unwired Planet Inc.’s UP.Link.
HDTV (high definition television) Digital television signals transmitted in the very high frequency
band by national and local TV stations. HDTV promises improved image broadcasts and compact discquality sound.
Hertz (Hz): A unit of measurement of one cycle per second, or one radio wave passing one point in one
second of time. Named in honor of Heinrich Hertz, the discoverer of the theory of radio waves.
High-yield or junk financing Bonds or other debts incurred by companies considered speculative or
below “investment grade” by major credit rating agencies such as Standard & Poor’s, Moody’s
Investors Service, Duff & Phelps or Fitch. Because a lender to such companies takes on a greater risk
that the borrower will default-a typical risk with start-up companies in PCS or financially stressed
companies in paging-the borrower will pay a higher interest rate or yield on the loan.
HLR (home location register) A database residing in a local wireless network that checks the identity
of a local subscriber.
I
iDEN (integrated digital enhanced network) A Motorola Inc. enhanced specialized mobile radio
network technology that combines two-way radio, telephone, text messaging and data transmission
into one network.
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ILEC (incumbent local exchange carrier) The historic local phone service provider in a market, often
a former Bell company. Distinct from CLECs, competitive local exchange carriers, new market entrants.
Immunity Immunity has special meaning in a 911 context. No CMRS or 911 provider, its employees,
officers or agents is criminally liable or liable for any damages in a civil action for injuries, death or
loss to person or property resulting from any act or omission in connection with the development,
adoption, implementation, maintenance, enhancement or operation of E911 service, unless such
damage or injury was intentional or the result of gross negligence or willful or wanton conduct.
Improved Mobile Telephone Service (IMTS) The commercial form of mobile telephone service
preceding cellular that allowed users to place and receive their own calls through the use of a dial or
keypad on the telephone. Prior service (MTS) required an operator’s intervention to actually place or
receive a call.
IMT-2000 The International Telecommunication Union’s name for the new third generation global
standard for mobile telecommunications.
IMTA (International Mobile Telecommunications Association) A trade group serving specialized
mobile radio and public access mobile radio carriers around the world.
InFLEXion The narrowband PCS technology developed by Motorola Inc. that allows for voice paging. It
has been adopted by carriers such as Paging Network Inc. and Conxus Communications Inc.
Interconnection Charge: A fee charged by the local telephone operating company to the wireless
operator for completing a call into the landline network (the PSTN).
Interconnection The connecting of one network with another, e.g. a cellular carrier’s wireless network
with the local exchange.
Interoperability the ability of a network to operate with other networks, such as two systems based
on different protocols or technologies.
IS (Interim Standard) A designation of the American National Standards Institute—usually followed
by a number—that refers to an accepted industry protocol; e.g, IS-95, IS-136, IS-54.
IS-136 The latest generation of the digital standard time division multiple access technology.
IS-41 The network standard that allows all switches to exchange information about subscribers.
IS-54 The first generation of the digital standard time division multiple access technology.
IS-661 North American standard for 1.9 GHz wireless spread spectrum radio-frequency access
technology developed by Omnipoint Corp. IS-661, for which Omnipoint was awarded a pioneer’s
preference license for the New York City market, is based on a composite of code division multiple
access and time division multiple access technologies. The company says IS-661 reduces
infrastructure costs and allows higher data speeds than mainstream GSM or TDMA platforms.
IS-95 The standard for code division multiple access.
ISDN (integrated services digital network) An advanced, high-capacity wireline technology used
for high-speed data transfer.
ITA (Industrial Telecommunications Association) A Washington, D.C. trade group serving private
wireless licensees such as airlines and oil companies.
ITU (International Telecommunication Union) An agency of the United Nations, headquartered in
Geneva, that furthers the development of telecommunications services worldwide and oversees
global allocation of spectrum for future uses.
K
Ka-Band Radio spectrum in the 18 GHz to 31 GHz range used by satellite communications systems.
Kilohertz (KHz) One thousand radio waves, or cycles, per second.
Ku-Band Radio spectrum in the 10.9 GHz to 17 GHz range used by satellite communications systems.
L
LAN (local area network) A group of client computers connected to a server.
LBR Low bit rate
LEC (local exchange carrier) A wireline phone company serving a local area.
LEO (low-earth orbit) A mobile communications satellite between 700 and 2,000 kilometers above
the earth.
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LifePage A service of the PCIA Foundation that donates pagers to individuals awaiting organ donor
transplants.
Lithium Ion: The latest form of battery technology, allowing the highest power-to-weight ratio (lots of
power for very little weight) and no “memory effect,” which plagues batteries made from other
materials.
Little LEO A low-earth orbiting satellite system primarily providing data services; e.g., Leo One,
Orbcomm.
LMCC (Land Mobile Communications Council) A trade group of frequency coordinators and
associations serving private users and commercial operators.
LMDS (local mulitpoint distribution service) Located in the 28 GHz and 31 GHz bands, LMDS is a
broadband radio service designed to provide two-way transmission of voice, high-speed data and
video (wireless cable TV). FCC rules prohibit incumbent local exchange carriers and cable TV
companies from offering in-region LMDS.
LNP (local number portability) The ability of subscribers to switch local or wireless carriers and still
retain the same phone number, as they can now with long-distance carriers. Wireless carriers don’t
have to offer LNP until March 2000 and want the deadline further postponed.
Local calling area The region across which the call is truly local, involving no toll charges.
LSGAC (Local-State Governmental Advisory Committee) An FCC-established group that is working
on an antenna-siting solution. The LSGAC will advise carriers and communities on antenna siting.
M
Medium-Earth orbit satellite system A communications system with satellites in orbits about 10,000
kilometers above the Earth. Such systems include those planned by Odyssey Telecommunications
International Inc., scheduled to launch in 2000.
Megahertz (MHz): One million radio waves, or cycles, per second. Equal to one thousand Kilohertz.
Messaging Synonymous with text paging, email or short messages received on alphanumeric pagers and
other wireless devices.
Microcell (also called Picocell and Nanocell): A cell having a very small coverage area, which could
be as small as one floor of an office building, one part of an airline terminal or one corner of a busy
intersection. These cells are typically used where coverage and/or capacity is strained and the use of
a normal sized cell would cause interference or be impractical to install. These cells transmit with
extremely low power outputs.
Microcellular A technology that directs the cellular signal into an isolated spot, leaving broader
coverage to conventional cell sites.
Middleware Middleware is the “mix-and-match” communications software that acts as a universal
translator between diverse radio frequency technologies and protocols. Middleware physically re
sides on the remote client and on a communications server, located between the client and the
applications server. The software eases computing and communicating with corporate information
and encourages applications development, making wireless data more attractive to corporate
customers.
MIN (mobile identification number) Uniquely identifies a mobile unit within a wireless carrier’s
network. The MIN often can be dialed from other wireless or wireline networks. The number differs
from the electronic serial number, which is the unit number assigned by a phone manufacturer. MINs
and ESNs can be electronically checked to help prevent fraud.
MIPS (millions of instructions per second) Used in defining digital signal processing capabilities.
Modem pools Racks of modems for more reliable cellular data communications.
Moratoria Moratoria (the singular form is moratorium) are waiting periods on the issuance of
construction permits by local zoning authorities. Moratoria are typically imposed to allow time for
localities to develop or refine ordinances dealing with antenna siting issues. However, they have been
used by some localities as tools to delay or block the rollout and/or expansion of wireless networks.
Such usage has resulted in lawsuits by carriers.
MOU (minutes of use) A measurement of wireless subscriber activity directly affecting revenue.
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MPEG-4 (Moving Picture Experts Group) Standard set by the International Telecommunications
Union for Telephony (ITU-T).
MSA (metropolitan statistical area) The coverage area of a city as in a cellular network. A U.S.
Census Bureau term.
MTA (major trading area) MTAs are usually composed of several contiguous basic trading areas. A
service area designed by Rand McNally and adopted by the FCC. There are 51 MTAs in the United
States.
MTSO (mobile telephone switching office) The electronic “middleman” between cell sites and the
public switched telephone network, processing traffic back and forth.
Multipath propagation Signal distortion resulting when part of a transmitted radio-frequency signal is
reflected from nearby surfaces on its way to a receiver. The “ghosting” effect on television screens
illustrates the multipath phenomenon.
Mutual compensation The concept that carriers must pay when they terminate traffic on the
networks of carriers with which they are interconnected.
Mutually exclusive applications Two or more applications for the same spectrum use rights.
N
NAMPS (narrowband advanced mobile phone system) NAMPS combines cellular voice processing
with digital signaling, increasing the capacity of AMPS systems and adding functionality.
NANC (North American Numbering Council) The FCC advisory group formerly responsible for
administering the North American Numbering Plan that oversees assignment of area codes, central
office codes and other numbering issues in the United States, Canada, Bermuda and part of the
Caribbean. NANP administration responsibility was transferred to Lockheed Martin.
Narrowband PCS The next generation of paging networks, including two-way, acknowledgment and
“wireless answering machine” paging.
NCIC (National Crime Information Center) A national database of crime and criminal information
operated by the Federal Bureau of Investigation.
NENA (National Emergency Numbering Association) NENA’s mission is to foster the
technological advancement, availability and implementation of a universal emergency telephone
number system.
Ni-Cad (Nickel Cadmium): A battery technology that is rapidly losing favor in the wireless industry.
These “Ni-Cads” don’t provide much power for wireless phones and suffer from a “memory effect”
that depletes their charge very quickly if the battery is not drained all the way down before
recharging.
NIMBY (not in my back yard) Public sentiment that opposes local placement of “undesirable”
facilities such as antenna towers or toxic waste dumps.
NmH (Nickel Metal Hydride): The most popular battery technology because it strikes a balance
between cost and performance. Has nominal memory effect and provides significantly better standby
and talk time than Ni-Cad batteries, but not quite as good as Lithium Ion batteries.
NMT (Nordic mobile telephone) An older analog cellular protocol used in Europe and elsewhere.
NOI (notice of inquiry) Often the predecessor to an FCC rule making, the NOI takes public comment
on a general topic. For instance, an NOI would ask “Do interconnection rates need regulation?” The
subsequent proposed rule making, if any, would offer a specific regulatory scheme and again be put
to public comment.
NOVRAM NOn-Volatile Random Access Memory. RAM that contains a constant power source.
Maintains data without the presence of external power (to the end of life of the internal source.
NTIA (National Telecommunications and Information Administration) The federal
government’s spectrum management authority.
Number pooling Increasingly popular tactic for conserving phone numbers. Numbers are returned by
all carriers to a central authority, which puts them in a pool, from which carriers receive numbers in
lots of 1,000, not 10,000 as was originally done. It relies on local number portability.
Numeric a display, message or readout that contains numerals only, such as in paging.
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O
OBRA 93 (Omnibus Budget Reconciliation Act of 1993) First legislation authorizing the FCC to
auction spectrum.
Off-peak Part of the day that wireless subscribers can expect to pay reduced airtime rates.
On circulation A common way the FCC commissioners decide items. An item is circulated among the
commissioners, allowing them to vote without having to come together as a group, which under
federal law would necessitate a public meeting.
One-stop shop Describes the all-in-one store where carriers sell wireless, long-distance, Internet
access and any other services they are able to sell in that market.
Operating cash flow/EBITDA A corporate income statement item that measures a company’s total
sales minus such items as operating expenses before interest, taxes, depreciation and amortization.
Because companies such as cellular, paging and PCS carriers often begin operations with huge capital
debts, EBITDA (earnings before interest, taxes, debt and amortization) is considered a better gauge of
their performance than net income, which likely will be skewed negatively by large debt payments
and other items.
Operating margin A measurement of a company’s relative profitability calculated by dividing
operating profit (the profit realized from one year’s business operations) by net sales. The higher the
percentage, the better.
Orbit A fixed circular, elliptical or other path around the Earth.
OTASP (over-the-air service provisioning) The ability of carriers to add new types of services to a
customer’s handset by using the wireless network instead of requiring the customer to bring in the
phone for reprogramming.
Over The Air Activation (OTAP): The process by which wireless carriers can activate a phone, assign a
telephone number, change or update features and much more from a remote location by sending
signals to the phone over radio frequencies. Eliminates the need for subscribers to physically take
their phones into retail stores or other locations when they want to change a number or add a
feature.
Overlay area code A solution to the scarcity of new phone numbers, overlays involve issuance of new
10-digit phone numbers for use alongside an area’s existing seven-digit numbers, which have a
different area code.
P
PACS (personal access communications system): An extended personal cordless technology
developed by Hughes Network Systems Inc. and Bellcore, planned for implementation by C-Block
licensee 21st Century Telesis.
Pager: A small device capable of receiving numbers and, in some cases, text messages that are sent
through a telephone connection or a computer. The earliest pagers were only one-way, i.e., they
could only receive information. More recent models allow the pager user to reply back to the sender,
called 2-way paging. Some pagers cannot respond, but have the benefit of guaranteeing that the page
will be received because they send a brief acknowledgment back to the system when they receive a
page. Until that acknowledgment is sent, the system will continue sending the page repeatedly.
PAMR (public access mobile radio) The European designation for services similar to specialized
mobile radio in the United States.
Partitioning Parceling a spectrum license into two or more geographic areas.
Pay phone service provider The company that owns and operates a pay phone.
PC Card Formerly called a PCMCIA card, a detachable card that can be connected to the mother board
inside a personal computer. It is used to link the PC to other devices to carry out a special function.
PCIA (Personal Communications Industry Association) A trade group representing PCS, SMR,
private radio and other wireless users and carriers.
PCS (personal communications services) A two-way, 1900 MHz digital voice, messaging and data
service designed as the second generation of cellular.
PDA (personal digital assistant) A portable computing device capable of transmitting data.
Peak part of the day that mobile phone customers can expect to pay full service airtime rates.
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PHS (personal handyphone system) The extended cordless system used primarily in Japan.
PIN (personal identification number) A code used by a mobile telephone number in conjunction
with an SIM card to complete a call.
POCSAG Referring to a standard developed by the U.K.’s Post Office Code Standards Advisory Group, a
paging protocol.
Pool consolidation The restructuring of 20 private land mobile services into two pools—public safety
and industrial/business—during the commission’s ongoing refarming proceeding.
POPs (persons of population) This term is used to designate the number of potential subscribers in a
market.
Pops: Wireless industry term for the number of people within the licensed area of a cellular or PCS
system.
Pre-emption A federal agency voiding a local ordinance or state law, asserting that the federal
government, not the state or locality, has ultimate jurisdiction on the matter.
Prepaid cellular A system allowing subscribers to pay in advanced for wireless service. Prepaid is
generally used for credit-impaired customers or those who want to adhere to a budget.
Price/earnings ratio A measurement of a company’s value as expressed by the stock market. P/E is a
company’s stock price divided by its net income per share. When a company has a high P/E, that
typically means investors are willing to pay a premium for its stock in anticipation that net income
will continue to grow at a certain pace. High P/Es are emblematic of established growth companies
such as Microsoft. Companies with lower P/Es would include banks, the Bell phone companies and
other sectors with slower growth rates. Low P/E also could signal a company is viewed negatively by
investors.
Project 25 An APCO-sponsored project to ensure interoperability of 800 MHz trunked Public Safety
communications systems produced by different manufacturers.
Project Angel AT&T Corp.’s code name for a wireless local loop residential network.
Proportional and owned subscribers Since many wireless carriers share certain markets in
partnership with other carriers, they report subscribership for those markets in proportion to their
share of the venture (e.g., their proportionate share of 10,000 subscribers in a market they share 5050 with a partner would be 5,000). Conversely, in markets they operate solely, carriers report all of
their subscribers as their own.
PSAP (public-safety answering point) The dispatch office that receives 911 calls from the public. A
PSAP may be local fire or police department, an ambulance service or a regional office covering all
services.
PSP A company that owns or operates pay phones.
PSTN (public switched telephone network) The worldwide voice telephone system, also called the
Bell System in the United States.
PSWAC (Public Safety Wireless Advisory Committee) The FCC group that identified the safety
community’s wireless needs, motivating the commission’s decision to reallocate 24 megahertz
currently used by broadcasters to public safety agencies.
PUC (public utility commission) The general name for the state regulatory body charged with
regulating utilities including telecommunications.
Punch list The list of sophisticated wiretapping function that the FBI wants common carriers to provide
under the 1994 digital wiretap law, but which the carriers say is too costly and may exceed the law’s
scope. The FCC has been asked to decide whether the industry’s standard is sufficient.
Push-to-talk (PTT): Works with half-duplex devices to transmit and receive voice traffic over the same
frequency. CB radios, police radios and walkie-talkies designed for family use would all be examples
of PTT devices.
R
Radio Common Carrier (RCC): An independent company licensed by the FCC to provide a service to
the general public that uses the radio spectrum. In the early 1980s, RCCs were also referred to as
“non-wireline” companies and were afforded one of two licenses for the original cellular spectrum in
each market in the United States.
Radio-frequency fingerprinting A process that identifies a cellular phone by the unique “fingerprint”
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61
that characterizes its signal transmission. RF fingerprinting is one process used to prevent cloning
fraud, since a cloned phone will not have the same fingerprint as the legal phone with the same
electronic identification numbers.
Rate center The geographic area used by local exchange carriers to set rate boundaries for billing and
for issuing phone numbers. Wireless industry groups decry the rate center concept as wasteful of
phone numbers because the concept is issued over larger areas.
RBOC (regional Bell operating company) The list of such companies includes Bell Atlantic, U S
West, Ameritech, Southwestern Bell and BellSouth.
Reciprocal billing The 1996 Telecommunications Act mandated that wireline companies pay wireless
companies for their cost of terminating calls that originated on the wireline network. Previously, only
wireless companies were obligated to pay compensation for calls originated on their networks but
terminated on the wireline network.
Recon petition Petition for reconsideration of an FCC decision.
Refarming An FCC initiative to promote more efficient use of the frequency bands below 512 MHz,
allocated to private land mobile radio services.
ReFLEX 25 The narrowband PCS technology developed by Motorola that allows for two-way text
messaging.
ReFLEX 50 The technology that denotes the proprietary two-way system implemented by SkyTel
Communications Inc.
Repeater Devices that receive a radio signal, amplify it and re transmit it in a new direction. Used in
wireless networks to extend the range of base station signals, thereby expanding coverage-within
limits-more economically than by building additional base stations. Repeaters typically are used for
buildings, tunnels or difficult terrain.
Reseller: An independent company that buys airtime in bulk at wholesale rates from carriers and then
sells the airtime directly to individuals or companies. The difference between the wholesale and
retail rate is their margin and they keep whatever portion of the margin they can after paying for all
other operating expenses, such as billing, customer service, etc.
Residuals Funds retailers receive after a cellular customer has activated service; the funds usually are
calculated based on the customer’s ongoing service.
Roaming Traveling outside a carrier’s local area.
ROE (return on equity) An indication of how much a company is earning on the investment its
shareholders have made in it. ROE is calculated by dividing the company’s net income by its
shareholder equity.
RSA (rural service area) Designation of a non-metropolitan area covered by a cellular licensee.
S
Satellite phone A wireless phone that uses mobile satellite service to send voice and data.
Shareholder rights provision or “poison pill” A stock plan intended to discourage or prevent
unwanted, “hostile” corporate takeovers by making them prohibitively expensive to the buyer.
Typically the plan will issue “rights” to existing shareholders that become effective once a would-be
acquirer’s stake exceeds a certain threshold, such as 10 percent or 15 percent of the outstanding
shares. The rights typically entitle the existing shareholders to acquire more shares at a significant
discount, creating a much larger pool of securities the acquirer must buy to succeed with the
takeover. Other variations may include the issuance of shares with superior voting rights.
SIM (subscriber identity module) Synonymous with smart card.
Simplex: A radio technology that allows only one-way communication. The FM radio in your car, or your
TV set, could be viewed as simplex devices.
Simulcast A signaling technique that broadcasts the same signal over each site in a network.
Slamming The unauthorized switching of a customer’s phone service to another carrier.
Sleep mode Designed to conserve battery life, this mode automatically turns off a terminal after it has
been unused for a specified period of time. The unit is reactivated when the keypad is touched.
Smart antenna An antenna system whose technology enables it to focus its beam on a desired signal
to reduce interference. A wireless network would employ smart antennas at its base stations in an
effort to reduce the number of dropped calls, improve call quality and improve channel capacity.
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Smart card A plastic card containing important data about a person’s identity to allow access to a
network or premises. Also, a card containing subscriber information, often inserted into GSM phones
for roaming to different countries.
Smart phone A class of wireless phones typically used to describe handsets with many features and
often a keyboard. What makes the phone “smart” is its ability to handle data, not only voice calls.
SMR (specialized mobile radio) A dispatch radio and interconnect service for businesses. Covers
frequencies in the 220 MHz, 800 MHz and 900 MHz bands.
SMS (short message service) Electronic messages on a wireless network.
SMT (surface mount technology) A surface mount device is a component, either active or passive,
having no separate leads but which is part of the component body to permit direct mounting on a
printed circuit board.
Soft handoff Procedure in which two base stations-one in the cell site where the phone is located and
the other in the cell site to which the conversation is being passed- both hold onto the call until the
handoff is completed. The first cell site does not cut off the conversation until it receives information
that the second is maintaining the call.
Soft key A key below the phone’s display that performs whatever function is listed on the display.
SOHO (small office/home office) A market that consists of individuals that work some of their time
at home and some of their time in an office.
Spectrum allocation Federal government designation of a range of frequencies for a category of use
or uses. For example, the FCC allocated the 1900 MHz band for personal communications services.
Allocation, typically accomplished in years-long FCC proceedings, tracks new technology
development. However, the FCC can shift existing allocations to accommodate changes in spectrum
demand. As an example, some UHF television channels were recently reallocated to public safety.
Spectrum assignment Federal government authorization for use of specific frequencies or frequency
pairs within a given allocation, usually at stated a geographic location(s). Mobile communications
authorizations are typically granted to private users, such as oil companies, or to common carriers,
such as cellular and paging operators. Spectrum auctions and/or frequency coordination processes,
which consider potential interference to existing users, may apply.
Spectrum cap A limit to the allocated spectrum designated for a specific service.
Spectrum etiquette Scheme under which various brands of equipment for unlicensed-band
communications can share the same frequencies. For example, a “listen-before-talk” etiquette would
have all devices first sense if a channel is clear.
Spread spectrum Jamming-resistant and initially devised for military use, this radio transmission
technology “spreads” information over greater bandwidth than necessary for interference tolerance
and is now a commercial technology.
SRAM (static random access memory) A memory technology used in pagers and handsets. So
named because it requires no refresh cycle, as required by dynamic RAM (DRAM) and therefore
consumes less power. SRAM maintains data only while power is applied.
SS7 (Signaling System 7) An international high speed signaling backbone for the public switched
telephone network.
Standby time The amount of time a subscriber can leave a fully charged handset turned on to receive
incoming calls before the phone will discharge the batteries.
Stratospheric platform Blimp-like platform for wireless telephone service in urban areas.
Strongest signal The concept that a wireless 911 call should be routed to the cell site with the
strongest link to the phone, regardless of which carrier holds the caller as a customer. The strength of
the call’s setup link isn’t always equal to that of the link the cell assigns for voice traffic; the latter can
be weaker.
Subordinated debt A corporate debt that is considered secondary to so-called “senior” obligations
both in terms of priority of payment and in claims to corporate as sets during bankruptcy. Financial
analysts have said C-Block PCS carriers have had difficulty borrowing money in the capital markets
because those loans would be subordinated to the debt they owe the government for their licenses.
Subscriber fraud A deception deliberately practiced by an impostor to secure wireless service with
intent to avoid payment. This is in contrast to bad debt, which occurs when a known person or
company has a payment obligation overdue and the debt cannot be collected.
Subscriber profiling The process of compiling subscriber usage information (such as frequency of calls,
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locations called to or from and monthly airtime usage), typically to identify potentially fraudulent
use or to identify customers likely to terminate service.
Symbian The joint venture between Ericsson Inc., Motorola Inc., Nokia Corp. and Psion to develop new
operating systems based on Psion’s EPOC32 platform for small mobile devices including wireless
phones or handheld personal computers.
System Identification Number (SID): A unique number assigned to every wireless operator in the
United States that is then programmed into the phones that subscriber’s to that service purchase.
S-Band The frequency spectrum near 2 GHz used for land based microwave and some mobile satellite
communications.
T
TDMA (time division multiple access) A digital air interface technology used in cellular, PCS and
ESMR networks.
Telematics The integration of wireless communications, vehicle monitoring systems and location devices.
Termination charges Fees that wireless telephone companies pay to complete calls on wireline phone
networks or vice versa.
TETRA (terrestrial trunked radio) An open digital trunked radio standard defined by the European
Telecommunications Standardization Institute.
Thin client A pen-based tablet computer used on a wireless local area network.
Third-generation A new standard that promises to offer increased capacity and high-speed data
applications up to 2 megabits. It also will integrate pico-, micro- and macrocellular technology and
allow global roaming. (Also see “3G.”)
TIA (Telecommunications Industry Association): A trade group representing manufacturers and
suppliers of communications and information technology products. TIA is a standards-developing
organization accredited by the American National Standards Institute.
Triangulation The lengthy process of pinning down a caller’s location using radio receivers, a compass
and a map.
Tri-mode handset Phones that work on three frequencies, typically using 1900 MHz, 800 MHz digital
or reverting to 800 MHz analog cellular when digital is not available.
Tri-Mode: The term applied to a phone that will work on 800 MHz analog, 800 MHz digital and 1900
MHz (also known as 1.9 GHz) frequencies.
Triple band A network infrastructure or wireless phone designed to operate in three frequency bands.
Trunking Spectrum-efficient technology that establishes a queue to handle demand for voice or data
channels.
Tumbling: The process of changing the Electronic Serial Number (ESN) in a single phone each time that
a phone call is made, thus allowing the user to make calls and have then illegally charged to someone
else’s number.
TCP/IP (transmission control protocol/Internet protocol) Internet protocol suite developed by
the U.S Department of Defense in the 1970s. TCP governs the exchange of sequential data. IP routes
outgoing and recognizes incoming messages.
Turnkey an entire system with hardware and software assembled and installed by a vendor and sold as
a total package.
U
UHF (Ultra high frequency) Referring to radio channels in the 300 MHz to 3 GHz band.
ULS (Universal Licensing System) The new Wireless Telecommunications Bureau program under
which electronic filing of license applications and reports of changes to licenses creates a database
that can be accessed remotely for searches. Using ULS, for example, the user can learn all the
specialized mobile radio licenses in a given region.
UMTS (Universal Mobile Telecommunications System) Europe’s approach to standardization for
third-generation cellular systems.
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Unified messaging Software technology that allows carriers and Internet service providers to manage
customer email, voice and fax messages from any phone, PC or information device.
Universal service The government’s aim, starting in the 1930s, of providing phone service to all,
regardless of distance from the switch or ability to pay. Today, universal service encompasses those
aims, plus a subsidy to public schools, libraries and rural health care facilities for telecom services.
Unvalidated phone A wireless phone lacking a service contract. Also called an unregistered phone.
Uplink The portion of a telecommunications path from the ground to the satellite. Also referred to as
the forward link.
USAT (ultra small aperture terminal) Satellite receive dishes for telemetry and other remote
monitoring, usually smaller than VSATs.
UWC-136 A third-generation wireless standard proposal based on TDMA technology that was
developed by the Universal Wireless Communications Consortium and is one of the 3G candidates
submitted to the International Telecommunication Union by the United States.
UWCC (Universal Wireless Communications Consortium) An industry group supporting IS-136
time division multiple access and IS-41 wireless intelligent network technology.
V
VCXO (voltage-controlled crystal oscillator) A crystal oscillator is an oscillator in which the
frequency is controlled by a piezoelectric crystal. Types of crystal oscillators include voltagecontrolled crystal oscillators (VCXO), temperature-compensated crystal oscillators (TCXO), ovencontrolled crystal oscillators (OCXO), temperature-compensated-voltage controlled crystal
oscillators (TCVCXO), oven-controlled voltage-controlled crystal oscillators (OCVCXO),
microcomputer-compensated crystal oscillators (MCXO), and rubidium crystal oscillators (RbXO).
VHF (very high frequency) Referring to radio channels in the 30 to 300 MHz band.
VLR (visitor location register) A network database that holds information about roaming customers.
Voice activation A feature that allows a subscriber to dial a phone by spoken commands.
Voice recognition The capability for cellular phones, PCs and other communications devices to be
activated or controlled by voice commands.
VSAT (very small aperture terminal) A small satellite dish installed at end-user locations.
W
W-CDMA (wideband code division multiple access) The third generation standard offered to the
International Telecommunication Union by GSM proponents.
WCS (wireless communications services) Frequencies in the 2.3 GHz band designated for general
fixed wireless use.
WIN (wireless intelligent network) The architecture of the wireless switched network that allows
carriers to provide enhanced and customized services for mobile telephones.
Windows CE The Microsoft operating system developed for handheld computing devices. Variations
of Windows CE also may eventually become a platform for applications used by communications
devices such as wireless phones or two-way pagers.
Wireless Using the radio-frequency spectrum for transmitting and receiving voice, data and video
signals for communications.
Wireless Application Protocol (WAP): A protocol designed for advanced wireless devices allowing
the easy transmission of data signals, particularly Internet content, to micro-browsers built into the
device’s software. Wireless Internet An RF-based service that provides access Internet email and/or
the World Wide Web.
Wireless IP The packet data protocol standard for sending wireless data over the Internet.
Wireless IT (wireless information technology) The monitoring, manipulating and troubleshooting of
computer equipment through a wireless network.
Wireless LAN (local area network) Local area network using wireless transmissions, such as radio or
infrared instead of phone lines or fiber-optic cable to connect data devices.
ASK THE WIRELESS WIZARD
65
Wireless PBX Equipment that allows employees or customers within a building or limited area to use
wireless handsets connected to an office’s private branch exchange system.
WLL (wireless local loop) A fixed service that competes with or substitutes for local wireline phone
service.
World Administrative Radio Conference (WARC) Biennial meetings of International
Telecommunication Union member nations to discuss and resolve global spectrum allocation issues.
WPDA (Wireless Partnership for Donor Awareness) The industry’s effort to raise organ and tissue
donor awareness.
WTO (World Trade Organization) An intergovernmental organization set up in 1995 to oversee the
rules of international trade, thus helping smooth the flow of trade, resolve disputes and organize
trade negotiations. The Geneva-based group, created as successor to the General Agreement on
Tariffs and Trade, in 1997 negotiated the agreement to open trade and investment in basic
telecommunications and information technology products.
X
X.25 A specification from the Consultative Committee on International Telephone and Telegraph on
layered protocols connecting computer terminals to a public, packet-switched network.
xDSL Designation for digital subscriber line technology enabling simultaneous two-way transmission of
voice and high-speed data over ordinary copper phone lines.
Y
Y2K (The Year 2000) Often used when describing the upgrade of computer systems that must
acknowledge the new millennium for billing customers and for other purposes.
Z
Zero coupon bond A debt instrument that pays all accrued interest at the bond’s maturity instead of
making regular cash payments to the bondholder during the life of the bond. Many PCS and other
wireless companies used zero-coupon bonds to finance their start-ups to ease the burden on their
cash flows during their early years of operation.
Zulu time Synonymous with Greenwich Meridian Time, a time designation used in satellite systems.
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NEW DIRECTIONS IN WIRELESS
Bibliography
Where can i get more information and what are some cool
wireless web sites?
ASK THE WIRELESS WIZARD
Still have a question after reading all of this stuff? No problem. You’re welcome
to submit a question to the Wireless Wizard anytime on his Web site and it’ll
appear in the Wizard’s forum along with the answer.
www.thewirelesswizard.com
CELLULAR TELECOMMUNICATIONS INDUSTRY ASSOCIATION (CTIA)
An industry association for cellular and PCS operators.
www.wow–com.com
FEDERAL COMMUNICATIONS COMMISSION (FCC)
The government entity that is responsible for allocating spectrum, licensing
carriers and preventing abuses of the public radio spectrum.
www.fcc.gov
PERSONAL COMMUNICATIONS INDUSTRY ASSOCIATION (PCIA)
An industry association for cellular, PCS, two–way radio and paging operators.
www.pcia.com
POINT.COM
A place to get updated rates for wireless services in the major markets in the U.S.
www.point.com
RADIO COMMUNICATIONS REPORT
One of the wireless industry’s oldest print publications, also found on the Web at
www.rcrnews.com
WIRELESS WEEK
The wireless industry’s most popular print publication, also found on the Web at
www.wirelessweek.com
WIRELESSNOW
Electronic news service for the wireless industry
www.wirelessnow.com
ASK THE WIRELESS WIZARD
67

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