THREAD--Following is an interesting related article, from America's Network. (Apologies if it's been posted. With all the euphoria around here I'm not even going to try to read all the messages!)
americasnetwork.com
Testing third-gen wireless: Now, that's a
challenge
Test and measurement tools for 2.5G and 3G wireless technologies are
needed, like, yesterday.
By Charles Mason
The mushrooming wireless industry is already dealing
with a shrinking number of qualified technicians. Yet, the
industry moves ahead with plans to develop and deploy
increasingly sophisticated technology that will place new
challenges on the workforce.
This paradigm means, in part, that there will be greater demands for test and
measurement equipment that can get the job done and, at the same time, be
relatively easy to use.
3G: A new angle
With thoughts turning toward the next generation of wireless technology,
vendors want to provide the right stuff for monitoring the coming
state-of-the-art networks. They also want to make sure that the test and
measurement equipment is as easy to use as possible.
"The importance of the user interface cannot be overemphasized," says Robert
Buxton, product marketing manager for wireless and test at Tektronix Inc.
(Beaverton, Ore.).
Tektronix has plans to support the wireless industry's transition to
third-generation (3G) mobile systems with measurement solutions "that
anticipate user needs," Buxton says. "And these needs, among others, include
ease of use. The training issue is one that we are constantly hearing from
carriers," he says.
The company is unveiling plans with a group of product announcements that
executives say will address every facet of the transition to 3G. These issues
include:
• Air interface and signaling tests;
• Design, quality of service monitoring and manufacturing test
requirements;
• Standards ranging from global system for mobilization (GSM) to
wideband code division multiple access (W-CDMA); and
• 2G, 2.5G and 3G technologies.
W-CDMA is a 3G wireless technology designed to deliver higher transport
capacity for high-speed data and low-cost voice services than today's wireless
networks.
Can't it wait?
The transition to the next generation and interim technology is a challenge for
the wireless industry. Until now, the range of measurement solutions for design,
evaluation and deployment of wireless systems has been limited to 2G tools
and general-purpose instruments.
"The wireless industry needs measurement tools that meet 2.5G and 3G needs
now," says Ross Nelson, product manager at Tektronix; "first for equipment
manufacturers involved in design and production, then for network providers
deploying new equipment. Test and measurement solutions will be key to the
successful development and installation of a 3G infrastructure."
New products debut at Wireless '99
During the Cellular Telecommunications Industry Association's annual
conference and exposition in February, Tektronix introduced a portfolio of
wireless measurement products that fulfill 2G, 2.5G and 3G needs. Buxton says
the new products supplement Tektronix's existing tools, such as the
AWG2021 Arbitrary Waveform Generator and the TDS794D Digital
Phosphor Oscilloscope, which are compatible with 3G requirements. These
new products include the following:
• 3000 Series Real-Time Spectrum Analyzers. There are three
models (3026, 3066 and 3086) in this series for air interface
testing that offer signal acquisition on spread-spectrum and
frequency-hopping signals. The 3086 delivers symbol rates and
analysis tools that meet W-CDMA and other 3G design needs.
• M366plus Release 5.0 Quality of Service Analyzer. This is a 2G
tool that enables network operators and manufacturers to
measure voice, data and fax quality in GSM networks.
• K1205 Protocol Analyzer with V1.2 Software Upgrade. This is
a signaling protocol analyzer for 2G network deployment and
quality of service testing. Version 1.2 provides new application
programs and supports a number of additional communications
protocols, Buxton says.
• Mobile Call Generation System (MCGS). This is an air interface
and signaling test system for GSM-based 2G networks. Buxton
says that this product provides equipment manufacturers and
network operators with a means for software verification, load,
roaming and system integration tests for all components in the
system;
• K1297 Protocol Analyzer with the General Packet Radio
Services (GPRS) Software Package. This is a signaling analysis
tool for GPRS (2.5G) analysis on GSM-based networks.
• FSIQ Series Signal Analyzers (FSIQ 3, FSIQ 7 and FSIQ 26).
FSIQ signal analyzers offer integrated spectrum and modulation
analysis for 3G, particularly for W-CDMA, and for today's
wireless standards, including GSM, IS-136 and CDMA. Buxton
says the FSIQ series is a toolset that can provide
‘uncompromised' adjacent channel power ratio (ACPR)
measurements on W-CDMA equipment.
The products are designed to address the research, development and design
needs of mobile wireless equipment manufacturers, according to Chris Loberg,
business development manager at Tektronix's U.S. Marketing Center. In
addition, the instruments' performance and measurement throughput delivers
important benefits in manufacturing test applications.
Not your typical testing needs
Third-generation wireless technologies are distinguished by their wider channel
bandwidths and more demanding measurement needs. W-CDMA is one such
3G technology. While W-CDMA standards are not fully defined, it is already
clear that W-CDMA ACPR measurement requirements will exceed the
capacity of most of today's test equipment.
Most existing spectrum analyzers offer little or no margin above the 70dB
dynamic range needed for the tests. Buxton says that vendors must take this
into consideration when designing 3G equipment. He explains that this reduces
ACPR measurement error to low levels. For research and design and
component test applications, the increased headroom makes it possible to
characterize new 2G or 3G mobile phone and base station designs with greater
accuracy. In manufacturing, the improved dynamic range allows narrower
guard bands, which provides higher yield.
Both Buxton and Loberg say that cost-saving is a major factor. They explain
that, unlike other W-CDMA ACPR measurement solutions, the FSIQ series
requires no external adapters or preselectors.
Moreover, the FSIQ series includes integral modulation analysis capability.
This spares users the expense of buying and supporting a separate instrument
for W-CDMA modulation quality tests. The FSIQ carries out modulation
analysis at rates up to 4.096 Mchips/sec.
Other vendors step up
Hewlett-Packard Co. (HP; Palo Alto, Calif.) has incorporated its code-domain
power measurement software for W-CDMA into the HP 89400 series vector
signal analyzer. This measurement capability enables wireless R&D engineers
to develop W-CDMA base stations for the experimental W-CDMA system
being tested at NTT DoCoMo, a major mobile communications operator in
Japan.
Last June, HP's code-domain power measurement solution was the first to be
successfully demonstrated on this system.
HP executives say that R&D engineers can accelerate the development of
W-CDMA base stations by using this new measurement to verify that
base-station systems transmit correct coding for all symbol rates. NTT
DoCoMo is coordinating the rollout of the first W-CDMA mobile network.
Last summer, HP's test solution was the first to be demonstrated successfully
during the indoor testing phase of the experimental W-CDMA system.
"This new code-domain power measurement software strengthens our suite of
test equipment for W-CDMA product development," says Duane Hartley,
general manager of HP's Microwave Instruments Division.
The software transfers signal information from the HP 89400 series vector
signal analyzer to a PC, where it performs W-CDMA code-domain power
measurements.
Code-domain power — the amount of power in each code channel relative to
the total signal power — can be determined for each of the 16 time slots in a
frame. A composite view simultaneously can display all symbol rates and
codes, according to Hartley.
After measuring the code-domain power of a system, R&D engineers can use
the modulation-domain analysis features of the HP 89400 to determine causes
of degradation. |
