WiFi
A Short Tour of Wi-Fi
Dr. Srikanth Subramanian, CKO, Nanocell Networks
802.11 &
WiFi
Future
WiFi
RF bands
Wi-Fi
overview
WiFi
Network
type
Wi-Fi
deployments
Technology
Evolution
Wi-Fi – A Wireless Success Story
Wi-Fi Calling
Wi-Fi present in all
laptops/APs
Wi-Fi in almost all
Phones and
tablets
Wi-Fi's next wave – presence in all
CE devices and more
(IOT)
Significant
traffic to come
from noncomputing
devices
Wi-Fi Traffic trends
Source: Cisco
Standards and Interoperability
Popularly known as
Wi-Fi
WLANs
(Wireless local
area networks )
Originally designed
to mimic Ethernet
IEEE
802.11
Globally reputed organization
for technical activities
Technical specs
Wi-Fi
Alliance
• Industry Consortium
• Focus on Inter-operability
and certification
Interactions
Driven by applications,
regulations and other factors
Wi-Fi Spectrum
Sensor/
smart grid
Outdoor/flexible use in some countries
2.4 2.5
GHz GHz
Sub
1GHz
3.5
4.9 5.0
GHz GHz GHz
5.8
GHz
60
GHz
Frequency (GHz)
Most popular
Wi-Fi band
Popular
Bluetooth
band
Used to be
Japan
specific
Gradually
becoming
mainstream
Unlicensed band in
most developed
markets
Future
band
More PAN and
video centric
than LAN
IEEE 802.11
Web browsing, E-mail,
YouTube
Application Layer
TCP/UDP
Transport Layer
IP
Network Layer
IEEE
802.11
Data Link Layer
Physical Layer
Remains the same as
in wired scenarios
Define PHY and MAC layers for
WLAN operation
Emulate wired
LAN (Ethernet)
Wi-Fi Technology Evolution – Rates and Speeds
IEEE Standard
802.11
(1997)
Max. channel 22 MHz
bandwidth
Technology
FHSS/D
SSS
802.11b
(1999)
802.11a
(1999)
22 MHz
20 MHz
DSSS
(CCK)
OFDM
802.11g
(2003)
20 MHz
OFDM
802.11n
(2009)
802.11ac
(2013E)
80 MHz
(160 MHz
optional)
802.11ad
802.11ax
1.8 GHz
40 MHz
MIMO +
OFDM
MIMO
(SU/MU)
+ OFDM
• Backward compatibility is always kept in perspective
Beam forming
+SC/OFDM
OFDMA
Upto 10 Gbps
Upto 7 Gbps
Up to
7 Gbps
600 Mbps
Max. PHY layer
2 Mbps
Data rate
11 Mbps
2.4 GHz
2.4 GHz
Spectrum
54 Mbps
54 Mbps
2.4 GHz
5 GHz
2.4 GHz
5 GHz
2.4 GHz
5 GHz
5 GHz
60 GHz
Wi-Fi Network Types
Infrastructure
Network
• Used in
homes,
offices &
hotspots
Ad-hoc Networks
802.11
ad-hoc
• Used in some
gaming devices
Mesh Networks
Wi-Fi
Direct
• Wi-Fi alliance
initiative for easy
to use peer-topeer connections
• Planned for widearea/large campus
deployments; now
used for extending
coverage in large
homes
Wi-Fi Infrastructure Network
Even a phone
can serve as AP
Basic Service
Set (BSS)
STA 1
STA 2
Bridge
between
802.11 networks and
non 802.11
networks
BSSID/SSID
are network
identifiers
STA 3
All communications on the
wireless network are routed
via Access Point (AP)
Most popular type
of 802.11 network
used in homes,
offices, and hotspots
How is your Wi-Fi made?
AP OEMs
• Cisco
• D-Link
• Mojo
• Liton
• Act-on
• Sinao
ODM vendors
• Qualcomm
• Broadcomm
• Marvell
Analytics
Chipsets
• Give AP boards based on reference design
and customized versions
AP Evolution Story
Typically 1 antenna, 2.4 GHz radio,
multiple Ethernet ports, 802.11b/g
days
Multiple antennas, multiple radios (2.4 and
5 GHz, dual band concurrent radios),
multiple Ethernet ports, integrated
cable/DSL/.. For retail markets
Lots of antennas, 3 radio support,
sensing/traffic generator plus normal AP
functionality, application layer monitoring
features
Wi-Fi Mesh Network
MP 1
MP 2
High power
outdoor MP
MP 3
MP = Mesh Point
Forwarding Path
Normal
NormalWi-Fi
Wi-Fi
connection
connection
MP 4
Wide area coverage for city-wide and
campus networks
Commercially used in large campus
and enterprise deployments
Mesh connectivity for
backhaul using Wi-Fi radios
Internet
Mesh becoming
popular for home
products for
better range
Wi-Fi Repeaters and Extenders
Source: Cablelabs
Wi-Fi and IoT
Power not a
big issue in
some cases
Reliable
connection
to Internet
Add WiFi/Retro fit
Wi-Fi
Wi-Fi AP present in homes
, hotspot, retail ,enterprise
etc.
Planned Wi-Fi
deployments have
good coverage
People
comfortable with
Wi-Fi
Cost
effective
solutions
available
New sub 1GHz solution
(Wi-Fi HaLow) announced for
low-power devices
Using Multiple Wireless Technologies for IOT
Thread/Zigbee
Capable
BB Interface
Sensors
Internet
BLE Radio
Wi-Fi capable
Phone
Sensors
Tablet
Wi-Fi AP
Thread/Zigbee
BLE capable
• Ability to access server data
Sensors
Smart Home/Enterprise Gateway
• AP vendors including BLE in home / enterprise APs
Wi-Fi calling - Motivation?
Roaming charges on cellular leads to
users using OTT apps (skype/viber
over Wi-Fi)
Cannot use the cellular
phone number
Internet
AP
Wi-Fi and cellular
radios present
PSTN
eNB/NB/BTS
• Poor signal in many indoor locations
• Lots of voice calls made from indoor locations
Wi-Fi calling
• Use of Wi-Fi for calling /receiving
using phone credentials (No apps)
Operator
Supported
Internet
AP
Core
Network
eNB/NB/BTS
• Any AP which allows access OK
PSTN
Handover to cellular to be taken care
Wi-Fi Competition; LTE in Unlicensed Spectrum
• Control signaling
• Mobility
• User data
Primary
Cell
EPC
Unlicensed
Spectrum5GHz
Combined use of BW for data
Secondary
Cell
Aggregation of
Licensed + Unlicensed
Anchor in the
licensed carrier
18
LTE and Unlicensed - approaches
Wi-Fi Offload
Not a lot of
momentum
but some
deployments
happening
LTE-U/LAA/MuLtefire
Lots of
interest
from
carriers
LTE Wi-FI
Aggregation
(LWA)
LTE Wi-FI
aggregation with
IPSEC(LWIP)
Wi-Fi camp’s response to
LTE-unlicensed approaches
LTE and Wi-Fi together – LWA
Licensed
Band
EPC
Both colocated
and non
co-located
cases of
eNB and
Wi-Fi AP
considered
Scheduling of Wi-Fi
downlink done by LTE
eNB
Aggregating WiFi and LTE @
radio level
Unlicensed
Band
• Carrier grade AP
• Needs interface to
communicate with LTE
eNB
R13 covers DL option
alone; specifications
completed
20
Star Trek Wi-Fi?
• Challenging RF overcome by
beamforming
Device 1
• Cable replacement
technology for high
bandwidth aplications
60 GHz
802.11ad
Device 2
• Potential future band due to large bandwidth availability
Future – 802.11ax
• Majority of deployments will evolve towards high density scenarios in the near future..
• To increase the real world throughput
achieved by users.
• To improve power efficiency for the battery powered devices…better IOT
• 2.4 and 5 GHz bands
Wi-Fi Big Picture
Ripe for
Innovation; Wi-Fi
Aware
Peer-topeer
access
Home
and
Internet
access
Adopt
higher
speed Wi-Fi
Potential
Bluetooth
replacement
Displays,
Set top
boxes
Enterprise
network
access
Interactions
with cellular
60 GHz
Wi-Fi usage ?
2.4 & 5 GHz
Wi-Fi
MBO and
OCE
802.11ax
More
usage of
5 GHz Wi-Fi
Wi-Fi Calling
Smooth
interaction
with carrier
LWA and
LWIP
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