With 22 UWB based Wireless-USB products
being certified, it's time to evaluate UWB technology. While most
WiMedia Alliance entries ran at less than 10% of the 480 Mbits/s PHY
rate over short distances, Pulse-LINK's CWave technology was fast enough
for multiple HD video streams over good distances.
EE Times link
download
(pdf)
----
On June 25, the Wi-Fi Alliance (www.wi-fi.org)
officially started its 802.11n draft 2.0 certification, and products
from 14 vendors (and counting) are now certified. But will these new
products work well side-by-side with their legacy counterparts? Can they
be phased into the existing network gradually, or will 802.11n systems
require exclusively 802.11n equipment?
Cabling I&M link
download
(pdf)
----
Report: Tests show
802.11n outperforming 802.11g,
EE-Times August 2007
Wireless LAN systems based on
draft-compliant IEEE 802.11n chipsets from four vendors are
significantly outperforming 802.11g-based systems—although with notable
variations between products. Since the Wi-Fi Alliance began certifying
draft 802.11n products on June 25, the number of certified devices has
been growing steadily and is now over 50. The Wi-Fi Alliance expects
these products to interoperate and to deliver approximately twice the
range and five times the throughput of legacy 802.11a/b/g networks.
EE-Times link
download (pdf)
----
Since testing began on June 25 2007, the
Wi-Fi Alliance has been certifying 802.11n draft 2.0 devices for
interoperability and backwards compatibility. As of this writing, the
number of certified products is 14 and counting. Will these devices
disrupt legacy networks? Will 802.11n-based video streaming applications
operating in the double-width 40 MHz channels squeeze out low data rate
applications such as VoIP and remote control?
WirelessNetDesgn link
download
(pdf)
----
Given the complex behavior of MIMO/OFDM
signals interacting with the environment, some form of channel emulation
is essential in providing an adequate picture of performance. By Craig
Mathias and Fanny Mlinarsky
EE Times link
download (pdf)
------
Wi-Fi CERTIFIED 802.11n draft 2.0 is a
certification program for products based upon the IEEE draft 2.0 802.11n
specification. At this writing, the final 802.11n amendment to the IEEE
802.11 standard is expected to be released in the second half of 2008.
802.11n is a major next step in the evolution of WLAN technology and
represents more than just a new physical layer.
Wi-Fi Alliance link
download (pdf)
------
Testing 802.11n,
Test & Measurement World, April 2007
Wireless LAN (WLAN) throughput
advancements introduced by the emerging IEEE 802.11n standard come at
the price of unprecedented technological complexity. This creates an
immediate need for sophisticated test systems that can help
manufacturers and service providers bring robust, well tested products
to market. Although the final standard will not be published until
mid-2009, draft 2.0 is now mature enough that companies such as Intel,
Broadcom, Atheros, Marvell, and Qualcomm have already released 802.11n
chipsets that will require only software changes in order to comply with
the final standard.
T&M World
link
download (pdf)
------
Despite the rapid growth of wireless mesh
networking technology as the primary infrastructure for several
broadband services, including wide-area voice and data transmission, the
industry lacks an established process for testing wireless mesh
networks. And, without thorough testing, mesh networks cannot be
deployed on a large scale. Consequently, pre-deployment testing that
automates the performance testing of wireless mesh networks in a
controlled laboratory environment is required to establish its
credibility for mission-critical metro-area network applications.
RF Design
link
download (pdf)
------
Buyers of Wi-Fi equipment and systems
must be assured that all products have the performance and stability to
carry mission-critical applications and data. However, testing of Wi-Fi,
or 802.11, devices and systems for performance and stability is a
challenge for the industry because of the complexity of the 802.11
protocol. That is compounded by the inherent mobility of the wireless
devices and the prevalence of radio frequency interference.
Network World
link
download (pdf)
------
New standard
to bring broadband video over WiFi to conferencing market, Mass
High Tech, February 27, 2006
Simple connectivity
has helped make IEEE 802.11-based Wi-Fi the network technology of choice
where data cabling is scarce. No longer tethered to a desk, you can
browse the Net or collaborate with colleagues from anywhere there is a
Wi-Fi signal. Could the next step in corporate conferencing be broadband
video over Wi-Fi?
Mass High Tech link
download (pdf)
------
Cellular or WiFi,
Test & Measurement World, April 1, 2005
As the adage goes: “The good thing about
standards is that there are so many of them.” Does the world need yet
another one? Yes—to converge a few of the existing ones. Convergence of
WiFi and cell technologies in a single handset will enable pervasive
access to voice and data indoors and out with one standard, one network,
and one device.
Test & Measurement World
link
download
(pdf)
------
Metrics And Methods Bring VoWLAN Success,
Wireless Systems Design, March 2005
Mobile phones have been a runaway
success for two decades. Over the years, however, the cellular market
has stabilized. Can Wi-Fi give the cell-phone industry a boost? The IEEE
802.11- based Wi-Fi data-networking technology has penetrated the
small-office/home-office (SOHO) market. Now, it is expanding rapidly
into the enterprise and public-access markets. Wi-Fi is well suited to
carry packetized voice, such as Voice over IP. It also can offer
cellular users better indoor coverage at a lower cost.
Wireless Systems
Design
link
download (pdf)
------
WiFi Testing Using
a Cabled RF Environment, Wireless Design & Development, December
2004
As Wi-Fi technology matures,
wireless LANs are moving from the relatively tolerant SOHO market to the
demanding enterprise — a market where high network performance is needed
to support mission-critical applications, a large number of network
users, and a diversity of network elements. Enterprise IT managers need
accurate performance data on wireless systems to ensure the
interoperability, functionality, and performance of the wireless
infrastructure. Testing of wireless access points, clients, and networks
is critical to developing WLANs hardy enough for enterprise adoption.
Yet WLAN testing is often conducted in unstable environments where it is
impossible to ensure the repeatability and reliability of test outcomes.
The result is a testing process that is costly and unreliable.
Wireless Design &
Development
link
download (pdf)
------
WiFi Metrics,
Test & Measurement World, October 1, 2004
The IEEE 802.11 Wireless Local Area
Network (WLAN) technology, commonly known as Wi-Fi, has been steadily
gaining popularity, keeping users on the go productively connected at
airports, in hotels, and even in front of living room TV sets. Most of
us who have experienced the freedom and flexibility of wireless
connectivity have no wish to return to tethered networking. So far,
wireless networking has been largely confined to the airport, hotel,
coffee-shop, and small-office home-office (SOHO) markets, where
performance is less important than cost. The new target for the wireless
industry is the lucrative enterprise market, but those of us who yearn
for 802.11 to take hold in the enterprise have to wait until the
technology proves itself sufficiently robust and ready to carry
demanding mission-critical applications. In enterprises, network
performance impacts productivity, and IT executives won't make the
decision to deploy 802.11 lightly.
Test & Measurement World
link
download (pdf)
===================================
Broadband 101: Installation and Testing,
Electrical Contracting & Engineering News,
October 2001
Today the Internet is an
information superhighway with bottlenecks at every exit. These congested
exits call for the deployment of broadband access to the homes and
businesses. Broadband technology lets you watch TV (video), browse the
Internet via a high-speed connection (data) and use the phone (voice)
simultaneously. Broadband access means support for data, voice and video
services over a single cable with an “always-on” connection.
download
(pdf)
------
Fiber Optic Gigabit Transmission and Field Testing Issues,
Cabling Installation & Maintenance,
June 2000
Today’s fiber optic installations are fast
increasing in number and in bandwidth to alleviate the throughput
bottlenecks on the backbone networks where traffic from multiple
workstations aggregates. This article examines the latest developments
in high speed Ethernet transmission over fiber optic media and discusses
the new field testing issues associated with these emerging standards.
download
(pdf)
------
Cable
Analysis: A Clear Picture,
Electrical Contracting and Engineering News,
April 1999
[file missing]
------
Testing Optical Fiber for Gigabit Ethernet,
Cabling Installation & Maintenance,
February/March 1999
[file missing]
------
Gigabit
Ethernet Over Category 5,
Gigabit Ethernet Conference,
February 1998
The twisted pair gigabit Ethernet
standard – 1000Base-T – is under development by the IEEE P802.3ab task
force and is expected to be ratified in the first half of 1999. The work
on this standard started in the latter half of 1996. In September 1997,
after a year of debate, the IEEE P802.3ab task force selected the
Enhanced TX/T2 line code for implementing 1000Base-T. The name –
Enhanced TX/T2 – was chosen because this signaling scheme has inherited
the symbol rate and spectrum of 100Base-TX and is based on the line code
used by 100Base-T21.
download (pdf)
------
The Inter-standard Gap,
International Wire and Cable Symposium,
November 1996
In an ideal world the networking and the
cabling standards would be inter-operable. The IEEE, ANSI and The
ATM-Forum standards committees developing new networking standards could
simply specify a cable plant compliant with TIA-568-A[1] or ISO11801[2].
This kind of cooperative arrangement among the standards organizations
could eliminate the redundancy of standardization effort and the
duplication of work. But when dealing with the enormous complexity of
data communications, can we honestly believe that a jump from 10 to 100
Mb/s will happen flawlessly and quickly, just as the standards dictate?
Has any significant advancement in networking technology ever occurred
without inter-operability issues? This paper provides an overview of the
emerging 100 Mb/s Local Area Networking (LAN) applications − their
physical layer needs and specifications. It examines how well the
generic cabling standards such as TIA-568-A[1] and ISO11801[2] address
the requirements of the emerging high speed LANs and demonstrates some
gaps between the ideal world and the reality today. How close are we to
our goal of standards interoperability? Can the industry standards ever
catch up with the accelerating pace of advancements in the data
communications industry? Before we attempt to answer these questions,
let’s examine the facts.
download (pdf)
Competitive test of
draft 802.11n products, June 2007
802.11n is the new generation WLAN
technology promising significant improvement in throughput and useful
range over legacy 802.11a,b,g equipment. In the home, 802.11n is
expected to provide triple play coverage including video distribution
through a typical house to multiple TV sets. In the enterprise/office
environment, 802.11n is expected to support mission-critical
applications with throughput, QoS and security rivaling 100Base-T.
download (pdf)
------
Test
Strategies for 802.11n MIMO Devices, October 2006
True to the trend of ever-increasing data
rates, the new IEEE 802.11n WLAN (Wireless LAN) transmission technology
based on MIMO (Multiple Inputs/Multiple Outputs) guarantees throughput
of at least 100 Mbps but can deliver up to 600 Mbps depending on the
complexity of the 802.11n radio and on the environment. MIMO is a highly
innovative advancement in wireless data transmission. It turns the
long-time nemesis of wireless – multipath – into a friend. Multipath is
a common occurrence indoors where the wireless signal reflects from
surfaces thus creating multiple signals that add together in the air.
While today’s 802.11 a/b/g radios struggle to separate the original
signal from this muddle, the MIMO radio actually takes advantage of
multipath to send multiple data streams via the available paths.
download (pdf) ------
IEEE802.11T –
WLAN Test Methods and Metrics, December 2005
Until now the surge of wireless networking
has been largely confined to the SOHO market, where performance has
taken a second place to cost. The new applications for the WLAN industry
are voice and video services that depend on performance. Formally
defining performance test methods and metrics is a timely and important
undertaking. Proper testing will shine the light on performance issues
and will help the WLAN industry to expand into the emerging cellular and
streaming video markets.
download (pdf)
------
Colliding Views on
Call Capacity Measurement, September 2005
With the emergence of voice over
WiFi and WiFi-enabled cell phones, call capacity of the WiFi
infrastructure has come under scrutiny. What is the call capacity of
WiFi? Can the WiFi infrastructure handle this capacity? How do we test
it? In pondering these questions some industry experts instinctively
focus on WiFi channel capacity. The trouble is – channel capacity and
infrastructure capacity are two different things. So the first question
is…
download (pdf)
------
Liftoff! Launching Wireless
Metrics, August 2003
Can wireless networks deliver
predictable performance to the enterprise? As IT managers scrutinize the
wireless solutions offered by a rapidly developing industry, performance
benchmarking will supply the answer. But before it can do so, vendors,
IT managers, users and test labs will need a well-defined and
comprehensive set of metrics and methods ready to deliver repeatable
results gathered over an inherently unpredictable underlying physical
layer, air. Such is the new data benchmarking challenge. When it is met
wireless performance testing will fulfill its role and accelerate the
adoption of wireless networking in the enterprise.
download (pdf)
==============================
Quality Metrics for Network Services,
April 2001
Year after year enterprises make
significant investments to improve the quality of network services
either through faster equipment or through more efficient protocols.
Yet, the networking industry still does not have any objective metrics
for Quality of Service (QoS). Different industry sectors have their own
definitions of quality. QoS is defined in three different unrelated ways
at the Ethernet layer, at the IP layer and for the ATM networks. These
disparate definitions of quality confuse the market and offer no
objective metrics of acceptable quality.
download (pdf)
------
Level III Tester Accuracy,
March 2001
Field testers certifying category 6
installations must conform to the Level III accuracy specifications
defined by TIA and ISO. When you invest time and money into the
certification job you want to be sure that the certification work is
valid. The best way to ensure certification validity is to use a tester
that is independently verified to meet Level III. The Agilent WireScope
350 has been independently verified by ETL to meet all Level III
requirements in both the Permanent Link and Channel configurations. This
white paper explains what Level III accuracy is and shows the
independent verification test results for the WireScope 350.
download (pdf)
------
The Monster Cords,
March 2001
Does our industry need bulky and
expensive Permanent Link test cords and complex field calibration
procedures to support Category 6 testing? Does a monster cord provide
better measurement repeatability or longer life? This paper demonstrates
that the answer to both questions is no.
download (pdf)
------
Fiber Optic Test
Issues – What to Measure and Why?
January 2001
Fiber optic networking
applications, such as Gigabit Ethernet, the emerging 10 Gigabit Ethernet
and Storage Area Networks (SANs) are focusing much of the industry’s
attention on the need to properly evaluate fiber optic installations.
Today there is no simple standards-based test method to assure that the
installed cabling can support new fiber optic applications.
download (pdf)
------
Understanding
FEXT and ELFEXT, September 2000
Far end crosstalk is a source of noise for twisted pair networks that
use more than one pair for transmission. It is important to qualify far
end crosstalk on the cabling used for running gigabit Ethernet.
download (pdf)
------
Category 6 – The
Ultimate Challenge, October 2000
Life was easy back in the category
5 days, although many of us did not think so back then. Today, faced
with the challenges of category 6, all of us can appreciate the good old
days. Why is certifying category 6 so much harder than certifying
category 5? The simple answer is – the test limits got significantly
stricter but the cabling technology is still catching up to these
limits. The result? High failure rate on category 6 installations.
download (pdf)
------
10 Gigabit Ethernet
Field Testing Issues, March 2000
Today’s fiber optic installations are
fast increasing in number and in bandwidth to alleviate the throughput
bottlenecks on the backbone networks where traffic from multiple
workstations aggregates. This article examines the latest developments
in high speed Ethernet transmission over fiber optic media and discusses
the new field testing issues associated with these emerging standards.
download (pdf)
------
Gigabit Transmission −
What's the Limit?, December 1998
As Local Area Networking (LAN)
technology advances into the realm of gigabit transmission, cabling
infrastructure is evolving to address the new physical layer
requirements of the new networks. This paper examines the signaling
environment pertaining to the new generation gigabit transmission over
twisted pair and fiber optic cabling and discusses methods of measuring
the headroom of network applications in the field.
download (pdf)
------
Cable
Analysis-Extracting Information from Measured Data, November
1998
Every cable tells a story. Cable
certification measurements can be presented as a string of numbers or as
a series of plots. Most of us are not good at reading numbers. It is
much easier to interpret graphical information. This paper explains how
to extract information from certification plots and talks about the
importance of preserving plot data for future analysis.
download (pdf)
------
Understanding the
Dynamic Range Requirements for Far End Crosstalk Measurements,
October 1998
This paper examines the
requirements for instrument dynamic range when performing field
certification of ELFEXT per TSB95, "Additional Transmission Performance
Guidelines for 100 Ω 4-Pair Category 5 Cabling " and TIA-568-A-A5,
"Additional Transmission Performance Specifications for 4-Pair 100 Ω
Enhanced Category 5 Cabling".
download (pdf)
------
WireScope 155 Accuracy
Analysis, July 1998
Category 5 cabling is the key enabling technology for bringing high
speed networking to the desktop. In order for installers and users of
category 5 cabling plants to be sure that each cabling run can deliver
high performance service, it is necessary to test cabling performance
parameters in the field. The draft TIA TSB-67 specification for field
testing defines the required test functions, test configurations, and
minimum tester accuracy necessary to reliably certify category 5 cabling
in the field. TSB-67 defines two measurement accuracy levels and the
instrument design parameters required to meet these overall measurement
accuracy ranges. Annex A of the draft TSB-67 specification defines a
mathematical model relating the overall accuracy of a field test
instrument to measurable instrument error parameters. Using this model,
it is therefore possible to obtain overall accuracy of a field tester
from data which can be measured using laboratory equipment. This article
describes the application of the TSB-67 accuracy analysis to design
qualification and production testing of the WireScope 155 field cable
tester. Inchcape Testing Services, ETL Testing Laboratories audited the
process of measurement and collection of the data presented in this
analysis.
download (pdf)
------
155 Mb/s ATM Bit
Error Rate Test, August 1996
This test demonstrates how the characteristics of an ATM channel above
100 MHz affect the robustness of 155 Mb/s ATM network. A series of Bit
Error Rate (BER) measurements were performed on two category 5 channels
that have similar properties up to 100 MHz but differ above 100 MHz in
that one of the channels has a defect at 124 MHz. The channel with the
defect above 100 MHz but that nevertheless passed the category 5
certification, exhibited BER of 9.6 x 10-8, which
significantly violates the maximum BER of 10-10
specified by the AF-PHY-0015.000 ATM Forum standard. By contrast, the
channel with consistent behavior up to 155 MHz exhibited BER of 1.1 x 10-11.
download (pdf)
------
The ATM Controversy,
August 1996 The question
of whether the 155 Mb/s ATM interface is properly supported by category
5 cabling has been a topic of some disagreement. Unfortunately for the
end user of ATM, the importance of the channel bandwidth above 100 MHz
has, on occasion, been misrepresented so as to promote systems and test
equipment unspecified above 100 MHz. Category 5, as specified, does not
satisfy the requirements of the 155 Mb/s ATM network This fact is
supported by theoretical analysis and by experiment1. However, in the
interest of allowing the existing standards to become established, the
physical layer requirements of this network have sometimes been
presented from the “best case” perspective. This paper analyzes the
channel bandwidth requirements of a few widely used 155 Mb/s ATM
products in the context of the best and worst case conditions defined by
the ATM Forum AF-PHY-0015.000 and TIA- 568 standards and demonstrates
that typical ATM products rely on the channel bandwidth beyond 100 MHz
for proper operation.
download (pdf)
------
Analysis of
Physical Layer Requirements for 155 Mb/s Twisted Pair ATM,
August 1996
This paper analyzes the physical
layer operation of 155 Mb/s twisted pair ATM equipment, presenting a
detailed examination of channel bandwidth utilization and the
performance trade-offs inherent in various bandwidth limiting
techniques. The data and analysis developed here support the conclusion
that in order to meet the required Bit Error Rate of 10-10,
the 155 Mb/s ATM application relies on the channel frequency response
beyond the 100 MHz band specified by category 5.
download (pdf)
January 2005, "Azimuth
Roaming Test Solution"
January 2005, "Azimuth
Voice over Wi-Fi Test Solution"
July 2003, "Azimuth
Test System - Preliminary Specifications"
April 2003, "Introducing
Azimuth 802.11 Test System"
November 2002, "smartAIR
summary"
January 2001, "Cable
ID Management and Printing"
January 2001, "Universal
Category 6 Link and Channel SmartProbes"
VON Boston, October-December 2007 - "Femtocell
Workshop"Interop New
York, October 2007 - "Advances
in Wireless Networking"
VON Chicago, September 2007 - "Fixed
Mobile Convergence"
Interop Las Vegas, May 2007 - "Moderator
slides"
VON, March 2007 - "Wireless
Mesh Network Performance"
Upperside WiMAX Summit, February 2007 - "Testing
Requirements for Successful WiMAX Deployment"
VON, September 2006 - "Mesh
networking panel (moderator)"
IMEC Leuven RF Technology Day,
September 2006, "IEEE
802.11n PHY Overview and Channel Models"
Upperside Wireless WiFi Convergence,
May 2006, “Fixed
Mobile Convergence VoWiFi Requirements”
Vrije Universiteit
Brussel RF Technology Day,
November, 2005, “IEEE
802.11n PHY Overview and Channel Models”
Internet Telephony,
October, 2005, “Cell-WiFi
Dual Mode”
VON,
September 2005, “Voice
over WiFi”
wVoIP,
September, 2005, “Delivering High Quality Wireless VoIP”
WiFi Planet, Cellular + WiFi, June 2005, “VoWiFi
Tutorial”
Upperside WiFi Voice,
May, 2005, “Voice
over WLAN”
Toyo, May 2005,
Voice over Wi-Fi Test Methodology Seminar
WiFi Planet, December 2004, “Designing
WiFi Gear for the Real World”
WiFi Planet, September, 2004, “VoWiFi Tutorial”
BiCSi,
August 2001, “Beyond
the Physical Layer - Network Performance 101”
BiCSi,
May 2000, “10
Gigabit Ethernet Transmission and Field Testing”
Networld+Interop, September 1999, “Cabling
for Gigabit and Beyond (moderator)”
BiCSi,
August 1999, “New Developments in Field Testing”
May 1999, "TIA,
ISO/IEC, IEEE Standards Update"
BiCSi Europe, August 1999, “Challenges
of Meeting Category 6 In The Field”
BiCSi,
January 1999, “Cable
Analysis - Extracting Information from Measured Data”
BiCSi,
September 1998, “Gigabit
Transmission - What's the Limit?”
BiCSi,
June 1997, “Gigabit
Ethernet Over Category 5”
ATM Forum,
1996, “Physical
Layer Requirements For 155 Mb/s Twisted Pair ATM”
International Wire and
Cable Symposium,
November 1996, “The
Inter-standard Gap”
BiCSi,
1996, “Cabling
Systems for Next Generation Networking”
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