Essential Distributed Antenna Systems (DAS) Deployment Testing

Essential Distributed Antenna Systems (DAS) Deployment Testing
Distributed Antenna
Systems (DAS)
Deployment Testing
DAS are becoming increasingly popular for delivering capacity and enhanced coverage to
meet the staggering increases in bandwidth-hungry mobile apps, particularly within public
venues and commercial buildings such as stadiums, shopping malls, airports, and enterprises.
DAS installations generally consist of a signal combiner that takes signals from various radio
frequency (RF) sources (on-site base stations or feeds from donor macro cells), a master
distribution unit, remote units, and antenna runs—with or without splitters.
Although no two DAS installations are the same, a typical deployment is driven either by a direct
connection to a radio base station or from a donor macro cell. Often, there are multiple RF feeds that are
combined and then passed to a master distribution unit. The master distribution unit then feeds remote
units via a variety of media—fiber, 75 ohm coax, or twisted pair. The remote units in turn feed the antenna
systems via 50 ohm coax. Multiple antennas can be fed from a single remote unit via splitters.
DAS Challenges
DAS architectures can vary significantly and use a wide variety of physical media for connectivity. This
creates a complex environment which, if not tested, validated, managed, and optimized, can have a
detrimental effect on an end user’s mobile experience.
These are just some of the challenges:
yy How will you test and validate the RF?
yy Has the coax, fiber, and twisted pair been installed correctly?
Example of DAS architecture
yy Is poor physical media connectivity causing performance issues?
yy Is there any RF interference?
yy Are the antennas positioned optimally?
yy How will I test the installation for mobile apps?
With tough acceptance standards, fewer technicians to cover complex floor plans, multiple RAN
technologies, and little time to be confident in the DAS birth certificate, you need the right tools and
solutions to get the job done on time and right—the first time.
Application Note
DAS Life Cycle
With any new network, or if you are optimizing an already installed
network, there are a number of phases that must be planned.
• What is the
from the
• Where
be placed?
• Install and
test the
• What
should the
power level
of the DAS
Commissioning/hand off
• Turn up
• Optimize
the RF
performance of
the DAS
• Ensure the
entire DAS
is working
as designed
• Ensure the
to perform
as designed
• Minimize
interference from
Fiber connectors can be inspected and certified using the Viavi
Solutions P5000i digital probe microscope with a variety of handheld
devices including Android devices and the SmartClass™ Fiber (SCF)
instrument. Optical insertion loss measurements can be performed
using the SCF or a Certifier40G. OTDR testing is done using the
T-BERD/MTS-2000. Coax testing can be performed using the
Certifier40G or CellAdvisor. Twisted pair certification can be performed
using the Certifier40G.
Benchmark and Design
Before any installation, you must have a clear understanding of
what the current network is offering. This can involve assessing the
existing macro coverage in terms of signal coverage, spectrum, and
power. To quickly and accurately perform these kinds of assessments,
RANAdvisor TrueSite is an ultra-portable solution with 3D dynamic
mapping integrated with IBWave to perform RAN and app testing in
real-time. And, the CellAdvisor Base Station Analyzer (BSA) provides
a deep analysis of RF characteristics including spectrum and signal
analysis, sweep testing, interference and PIM detection.
At this stage, we are bringing the install into service. We can use
the Viavi CellAdvisor Cable and Antenna Analyzer for RF testing (for
example, DTF, VSWR). Uniquely, we can also test fiber from the same
instrument. RANAdvisor TrueSite provides service testing mapped
to position and RAN metrics. We may also need to test the backhaul
depending on the DAS architecture with the T-BERD®/MTS-5800.
RANAdvisor TrueSite
CellAdvisor CAA with
P5000i microscope
Optimization, Operation, and Maintenance
SmartClass Fiber with
P5000i microscope
Once the DAS is operational, we need to keep the RF characteristics
optimized to ensure maximum service quality. RANAdvisor TrueSite
lets us measure macro ingress and missing or faulty antennas as
well as walk test mobile apps. The CellAdvisor BSA analyzes RF
performance across a wide spectrum performs simple optical power
measurements for fiber connector certification. For advanced
detection and location of fiber faults or breaks, use the T-BERD/MTS2000. And, monitoring backhaul with the JMEP solution will ensure
optimized end-to-end service delivery.
CellAdvisor Base
Station Analyzer
The main testing element at this stage is certifying that physical
media meets the required performance specifications.
Viavi is the only vendor that can truly surround a DAS cell site,
ensuring optimal service through all life-cycle phases. With the ability
to cloud-enable test results with StrataSync, you can trust Viavi to be
with you every step of the way for any DAS deployment.
Typical tests include:
yy Fiber inspection to certify the quality of the fiber connectors and
measure insertion loss
yy Using an optical time domain reflectometer (OTDR) to characterize
installed-fiber build quality
yy Ensuring that 75 ohm and 50 ohm coax runs have acceptable return loss
(RL/VSWR) and insertion loss (IL)
yy Certifying twisted pair cabling meets the required category or class
requirements (Category 6A, for example)
Contact Us
+1 844 GO VIAVI
(+1 844 468 4284)
To reach the Viavi office nearest you,
© 2015 Viavi Solutions, Inc.
Product specifications and descriptions in this
document are subject to change without notice.
30175909 900 0814
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF