26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
wireless local loop
By
Dr.Izhar-ul-Hq
ICT, ISLAMABAD
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
What is WLL
WLL stands for Wireless Local Loop
and it is basically the use of radio to provide
a telephone connection to the home.
It is sometimes called radio in the loop (RITL)
or fixed-radio access (FRA).
When WLL connects subscribers to the public
switched telephone network (PSTN), radio
signals are used as a substitute for copper for
all or part of the connection between the
subscriber and the switch. Included in this is:
cordless access systems, proprietary fixed
radio access, and fixed cellular systems.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Basic WLL communication system
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Copper versus Wireless: The Cost of the Last Mile
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Overview
• Throughout the world of telecommunications professionals
there has been a dramatic rise in interest in the WLL
technology. In the late 20th century, industry analysts
predicted that the global WLL market would reach millions
of subscribers by the year 2000. An article in ‘Red Herring’
magazine in 1997 predicted that, “the WLL market is
expected to grow from $563 million in 1996 to at least $6.3
billion in 2002”. Much of this growth is occurring in
emerging economies where half the world's population
lacks plain old telephone service (POTS). Developing
nations like China, India, Brazil, Russia, and Indonesia are
looking to WLL technology as an efficient way to deploy
POTS for millions of subscribers—without the expense of
burying tons of copper wire. Later on in this document the
economics of WLL will further be delved into.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
• One of the best economic contributions WLL
makes in developed economies is that it helps
to unlock competition in the local loop, this
enables new operators to bypass existing
wireline networks to deliver POTS and data
access. It will be shown throughout that the
question isn't “will the local loop go wireless?”,
but, “when and where?”. The aim of this
Lecture is to discuss the history and basics of
WLL, and look at the impact in Pakistan and
the world. It will also examine the markets both
past and present, and attempt to judge the
future for this technology.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
History of WLL
Wireless access first started to become a possibility in
the 1950s and 1960s as simple radio technology
reduced in price. For some remote communities in
isolated parts of the country, the most effective
manner of providing communication was to provide a
radio, kept in a central part of the community. By the
end of the 1970s, communities linked by radio often
had dedicated radio links to each house, the links
connected into the switch such that they were used in
the same manner as normal twisted-pair links. The
widespread deployment of the cellular base station
into switching sites helped with cost reduction. Similar
access using point-to-point microwave links still
Dr IZHAR-UL-HAQ
26 June 2007
continues
to be widely used today.
CIIT, Islamabad
During the reunification of West and East Germany,
much funding was put into increasing the teledensity
in East Germany. The installation of twisted-pair
access throughout would have been a slow process.
In the interim, cellular radio was seen to offer a stopgap measure to provide rapid telecommunications
capability. So in East Germany a number of cellular
networks, based upon the analog Nordic Mobile
Telephone (NMT) standard, were deployed in the 800
MHz frequency range. The key difference was that
subscribers had fixed unit mounted to the sides of
their houses to increase the signal strength and hence
allow the networks to be constructed with larger cells
for lower costs.
IZHAR-UL-HAQ
Thus,
26 June 2007
we see the first WLL network wasDrCIIT,
born.
Islamabad
Historical Path
Early 1950s.
Single-channel VHF subscriber equipment
was purchased from Motorola, but the
maintenance costs were too high as a
result of the valve technology used and
the power consumption too high. The trial
was discontinued and the subscribers
were connected by wire
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Mid-1950s.
Raytheon was given seed funds to
develop 6 GHz band equipment, which
would have a better reliability and a lower
power consumption. The designers failed
to achieve those goals and the system still
proved too expensive
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Late 1950s.
Some equipment capable of providing
mobile service to rural communities was
put on trial. Users were prepared to pay a
premium for mobile use, but the system
still proved to be too expensive in a fixed
application for which users were not
prepared to pay a premium.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Early 1960s
Systems able to operate on a number of
radio channels were developed,
eliminating the need for each user to share
a specific channel and thus increase
capacity. The general lack of channels and
high cost, however, made these systems
unattractive.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Early 1970s.
A Canadian manufacturer developed
equipment operating at 150 MHz that
proved successful in serving fixed
subscribers on the Island of Lake Superior.
The lack of frequencies in the band,
however, precluded its widespread use.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
1970s Late.
The radio equipment from several US
manufacturers was linked to provide
service to isolated Puerto Rican villages.
The service was possible only because
the geographical location allowed the use
of additional channels, providing greater
capacity than would have been possible
elsewhere.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Early 1980s.
• Communication satellites were examined
for rural applications but were rejected as
being too expensive.
• 1985. Trials of a point-to-multipoint radio
system using digital modulation promised
sufficient capacity and reliability to make
WLL look promising.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Four different flavours of WLL
systems
Cellular-based systems consisting of a network of base
stations. The older systems are usually based on
analogue technology, which is well proven and low-cost,
but provides reduced speech quality, limited data
capacity and low security. Examples include NMT
450/900, AMPS, TACS, N-AMPS. The newer digital
systems offer better spectrum usage and are costeffective for voice but are less standardised and still
provide only limited fax/data throughput. Examples
include GSM, DCS1800/PCS1900, IS-136/D-AMPS,
IS-95 800/1900.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Cordless-based systems.
These provide efficient
spectrum usage in high
densities but with limited
range, making high
infrastructure costs for smaller
cell sizes.
Examples include
DECT, CT-2, PHS.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Proprietary systems. These are usually
custom-designed for the application and
provide high quality voice and data
services, and other enhanced services.
While many of these systems provide
superior service to the cordless and digital
cellular standards, they must overcome
the inertia created by the high installed
base of the older technologies. These
include FDMA, TDMA, CDMA systems,
such as the products made by Qualcomm
and Granger.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Satellite-based systems, as described
above, are also proprietary and are mainly
focussed on the mobile market, but fixed
line access is also envisaged in a few
years. These provide global coverage in
virtually all environments, but currently
have very high usage costs and there are
still unresolved domestic control issues.
Examples include Iridium and Globalstar.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
WLL encoding
•
•
•
•
26 June 2007
Safety
Security
Minimum of errors
Most efficient data transfer
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Speech encoding
In digital radio systems it is necessary to turn
voice signals, which analog into a digital data
stream. Speech encoding is a highly complex
topic and a full treatment is well beyond the
bounds of this talk. The simplest speech
encoders are essentially analog-to-digital
converters. The analog speech waveform is
sampled periodically, and the instantaneous
voltage level associated with the speech is
converted into a digital level. The two main
parameters are: how frequently the speech is
sampled "sample rate" and how many different
bits are used to describe the voltage level.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Error-correction coding and
interleaving
Information transmitted via a radio channel is liable to be
corrupted. Interference, fading and random noise cause
errors to be received, the level of which depends on the
severity of the interference. Error correction is widely
deployed in mobile radio, where fast fading is almost
universally present. It is less critical in WLL, where the
LOS path results in less severe problems. Nevertheless
it is still necessary, especially for computer data transfer.
Error-correction systems work by adding redundancy to
the transmitted signal. The receiver checks that the
redundant data is as expected; if it is not, the receiver
can make error correction decisions. Error-correction
methodologies fall into two categories, block coding or
convolutional coding. Both are highly involved and
mathematical and are beyond the scope of this talk.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Ciphering
Almost all modern radio systems rely on some
form of ciphering to provide secure transmission.
The use of such security techniques both
reassures the user that the conversation cannot
be overheard and allows the operator to
authenticate the user. Most ciphering schemes
are relatively straightforward. The base station
and the subscriber unit agree on a "mask" on a
call-by-call basis. To the covert listener, who
does not know the mask, the data is
incomprehensible.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Multiple access
WLL technologies have differed over the
years in the multiple access technologies
that they use. A decision about which
technology to adopt will depend upon the
application. Each operator has a given
amount of radio spectrum to divide among
its users. There are broadly three main
ways to do this
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
• Frequency Division Multiple Access (FDMA),
in which the frequency is divided into a number
of slots and each user access a particular slot
for a length of a call
• Time Division Multiple Access (TDMA),
in which each user access all the frequency but
for only a short period of time
• Code Division Multiple Access (CDMA),
in which each user access all the frequency for
all the time but distinguishes the transmission
through the use of a particular code
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
CDMA: One of Multi-Access Technology
Code
CDMA
Time
User 3
Time
User 2
User 1
TDMA
Frequency
User 3
User 2
FDMA
User 1
Time
Frequency
User 1 User 2 User 3
Frequency
26 June 2007
All users obtain
service channel
at the same time
and within the
same frequency
band
Service channels are
allocated to different
users at different times,
for example: GSM
Service Channels are
allocated to different
users at different bands,
for example: TACS
system
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Overview: What is CDMA?
 CDMA stands for "Code Division Multiple Access “
 CDMA is a 3G-based technologies and can works in multi frequency
band(450MHz, 800MHz, 1900MHz, 2.1G) .CDMA includes a family of
standards developed by 3GPP2: CDMA2000 1X, CDMA2000 1xEV-DO
and CDMA2000 1xEV-DV.
 It is a popular technology and growing rapidly in both mobile and WLL
environment Currently, Over 212 Millions subscribers adopt CDMA
technologies.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
What is CDMA450?
-----Multiple Working Frequency Band
 CDMA450 is a CDMA2000 system deployed in 450 MHz
 CDMA450 is the best choice for WLL with best coverage performance
 Massive CDMA450 Successful cases both in developing and developed
country
F-Band
Up link
Down link
1
450MHz
450 ~ 457.5
460 ~ 467.5
2
800MHz
824 ~ 849
869 ~ 894
3
1900MHz
1850 ~ 1910
1930 ~ 1990
4
2100MHz
1920 ~ 1980
2110 ~ 2170
450MHz
26 June 2007
800MHz
800MHz
2.1GHz
1900MHz
2100MHz
Dr IZHAR-UL-HAQ
CIIT, Islamabad
CDMA System architecture introduce
Mobile IN
SMSC/MMSC
Data Service
Platform
Internet
OMC
HA
HLR
GMSC
MSC/VLR
PDSN/FA
AAA/AN-AAA
PSTN
Circuit domain Architecture
Packet domain Architecture
BSC/PCF/IWF
Outdoor
Macro BTS
Indoor
Macro BTS
SoftSite
iSite/SoftSite
SoftSite
Fixed Terminal
26 June 2007
Handset
Dr IZHAR-UL-HAQ
CIIT, Islamabad
WLL: Wireless Local Loop
 Wireless is now accepted as an alternative local loop
technology and its use has increased dramatically by
incumbents and new entrants throughout the world.
 WLL involves the final connection between the existing telecom
infrastructure and a subscriber's home by wireless technologies
rather than cable
 CDMA WLL technology, which is wireless based, is ideally
suited for urban regions of Pakistan as well as congested rural
areas where it is extremely difficult to lay the cables
 CDMA WLL: an affordable alternative for wire line voice and
internet access services
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Wireless Local Loop is booming
In low telecom penetration countries, there is tremendous demand for
new business and residential telephone service. More and more
operators are looking to wireless technologies to rapidly provide
thousands of new subscribers with high-quality telephone service at a
reasonable price.
Existing landline operators can extend their network with WLL
Cellular operators can capitalize on their current network to deliver
residential service with WLL
New service providers can quickly deploy non-traditional WLL
solutions to rapidly meet a community's telephony needs
The unique features and benefits of CDMA make it an excellent
technology choice for fixed wireless telephone systems.
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
What Problems PTCL Meet for Seamless Coverage
Last mile access - Trouble in fixed network
C.O
High investment
•Transmit cable expense
•Land rent
C.O
Long deployment delays
C.O
•Can’t meet increasing market
No mobility
C.O
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Service provision Difficulty in rural areas
Convenient Telecom will stimulate Economy
Fact: Low telecom penetration in Rural Area!
• Fixed Line:
• High investment, Hard for maintenance
• Higher Density area is far away from C.O.
or ONU
• Tough terrain: Mountains, Rivers, Lakes,
Deserts, Gobi and Grassland, etc.
• Lack of infrastructure: transmission...
• Low productiveness
• Low population density with broad area
• Less traffic per user
• Maintenance cost might be higher than
revenue
• Satellite Transmission:
Subscribers
Penetration
Fixed line
234,000
9.24%
Rural
13,000
0.5%
Mobile
279,000
10.54%
Internet
33,000
1.3%
（example: Tibet rural service situation）
• High cost, unbearable for public
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
WLL is The Best Solution
Low investment
•Transmission in the air, no cable cost
•few infrastructure expense
Quick deployment
•attract more sub., especially high-end
sub.
•Flexible network, easy adjustment
•Meet the need of increasing market
BTS1
Wide coverage, attract new
sub.
•Remote area
BTS2
Provide limited mobility
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
CDMA450 WLL, an Excellent but Affordable Offering
450MHz has the best radio propagation for broader coverage;
Lower frequencies are the key to reducing cost
Especially suitable for broad, low-density coverage, due to long-range propagation
( up to 30 km )
Excellent ability to provide urban coverage due to good “line of sight” propagation
characteristics
CDMA450 system is a cost-effective 3G solution
CDMA2000 1X, up to 153.6kbps data rate ( in average of 80 Kbps ),
CDMA2000 1xEV-DO, up to 2.4 Mbps data rate ( in average of 800 Kbps )
Lower infrastructure cost results from broad coverage
Low initial investment, then scale capital investment with the subscriber growth
The 450 MHz range has multiple bands available in many
countries
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
CDMA450: Better choice for Broadband Access

It is particularly significant in rural areas where currently Internet
access is slow dial-up;

Remote education, telemedicine, agricultural and industrial support
and government services are always accompanied by high data
speed internet access requirements;

CDMA450 is prettily suitable for broad coverage with lower cost vs.
other expensive data access solutions;

Enjoy roaming and “always on” service;

Excellent feature of urban better coverage, results from the better
radio propagation;

Today 153 Kbps peak value of high-speed data service available, in
average of around 70 Kbps, and late in EV-DO, provide 2.4 Mbps
peak data rates service, in average of 800 Kbps;
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Summary of CDMA WLL Feature
Frequency
multiple choice: 450M, 800M and 1900M
Maturity
widely application, more than 250 M subs over the world
Cost
The lowest cost per sub
broad coverage(30km for 450Mhz)
high integration
high spectral efficiency
Capacity
1 CDMA frequency bandwidth = 4 time GSM /4 time Analog /20
time DECT / 30 time PHS
Service:
max. Data rate 153.6kbps,
Voice service, circuit data service, packet service
Evolution
evolve to 1xEV- DO or 1xEV-DV smoothly
Dr IZHAR-UL-HAQ
26 June 2007
CIIT, Islamabad
System Feature: Larger Coverage, Lower Cost
k subs
5
4
3
2
1
0
CDMA450 conventional coverage
WCDMA
2100
Voice Capacity
in 5MHz
6
CDMA450 extended coverage
GSM with high efficiency technology
GSM conventional coverage
1km
GSM extended coverage
10km
Coverage
30km
Frequency(MHz)
Cell radius (km)
Cell area (km2)
450
850
950
48.9
7521
1
29.4
2712
2.8
26.9
2269
3.3
1800
1900
2100
14.0
618
12.2
13.3
553
13.6
12.0
449
16.2
Relative Cell Count
450MHz has the best radio propagation
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
System feature: Multiple Transmission Modes
E1/T1
Optical fiber
HDSL
Microwave
Satellite
Satellite
BSC/PCF
E1/T1
iSiteC
SDH622/
SDH2.5G
HDSL
Softsite
Softsite
26 June 2007
Optical fiber
Microwave
Dr IZHAR-UL-HAQ
CIIT, Islamabad
26 June 2007
Projected WLL Subscribers by Region
Dr IZHAR-UL-HAQ
CIIT, Islamabad
CDMA: popular technologies in world
CDMA surpasses
212 Million global subscribers
SOURCE: WWW.CDG.ORG
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
subscribers in Asia Pacific and North America
Asia Pacific CDMA
Subscriber Growth
History:
December 1997
through June 2004
Percent of total: 41.8%
Percent growth:41%
by year
SOURCE: WWW.CDG.ORG
North America CDMA
Subscriber Growth
History:
December 1997
through June 2004
Percent of total:40.3%
Percent growth: 18%
by year
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
CDMA Worldwide Subscriber Growth Analysis:
SOURCE: WWW.CDG.ORG
One Year Period June
2003 through June 2004
and Second Quarter 2004:
April, May, June
Worldwide Growth
One Year
Region
Jun-04 Subscribers
Jun 03 - Jun
04
2nd Quarter 2004
Percent
Growth
Mar 04- Jun
04
Percent
Growth
Asia Pacific
88,800,000
25,710,000
41%
4,400,000
5%
North America
85,600,000
16,725,000
24%
4,200,000
5%
Caribbean &
Latin America
34,800,000
5,250,000
18%
1,800,000
5%
3,320,000
740,000
29%
70,000
2%
212,520,000
48,425,000
30%
Europe, Middle
East & Africa
26 June 2007
Total
Dr IZHAR-UL-HAQ
10,470,000
5%
CIIT, Islamabad
CDMA 450 worldwide deployment
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
EVOLUTION OF CDMA2000
• IT EMERGED FROM EIA/TIA IS-95
STANDARD
• IMPROVED UPON REVERSE LINK
• INTRODUCED ADVANCED VOCODING
SERVICES
• IMPROVED POWER CONTROL
FUNCTIONS
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
TECHNICAL SUPERIORITY OF
CDMA
• LINE OF SIGHT IS NOT REQUIRED AS IN
HIGHER FREQUENCY SYSTEMS
• RANGE OF TRANSMISSION IS HIGHER THAN
DECT/PHS SYSTEMS
• BETTER COVERAGE, CAPACITY AND
HIGHER DATA RATE AVAILABLE COMPARED
TO AMPS, GSM ETC
• LOWER PRICE COMPARED TO
PROPERIETSRY SYSTEMS
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
COMPETETIVE ADVANTAGE
• GREATER SPECTRAL EFFICIENCY-MORE THAN 35 USERS PER
SECTOR PER 1.25MHz
• SUPERIOR VOICE QUALITY-13 Kbps QCELP, 8 Kbps QCELP,
EVRC, SMV
• FEWER DROPPED CALLS-SOFT AND SOFTER HAND-OFF, CELL
BREATHING
• LOWER TRANSMISSION POWER-LONGER BATTERY LIFE-TIME
• HIGHER DATA THROUGHPUT RATES-153 Kbps with release 0,
307.2Kbps with Release A
• ENHANCED GLOBAL ROAMING CAPABILITY-MULTIBAND,MULTI-MODE HANDSETS AVAILABLE
• INHERRENT VOICE SECURITY-2^41 LENGTH PN SEQUENCE
• DATA INTEGRITY-ADVANCED ENCRYPTION TECHNIQUES
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
COVERAGE ADVANTAGE
• 450 AND 800 MHz SYSTEMS OFFER
MORE COVERAGE
• IN TRADITIONAL TDMA SYSTEMS
SYNCHRONIZATION BETWEEN BTS
AND SUBSCRIBER TERMINAL ARRISE
BUT IN CDMA SYSTEMS……..
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
VOICE CAPACITY ADVANTAGES
• MORE THAN 45 ERLANGS OF VOICE
CAPACITY PER SECTOR PER 1.25MHz
CARRIER
• 3-5 TIMES MORE CAPACITY THAN
THAT OFFERED BY GSM
• DOUBLE THAT OF IS-95
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
VOICE CAPACITY ADVANTAGES
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
DATA CAPACITY ADVANTAGES
• SYSTEMS WITH FREQUENCIES
HIGHER THAN 2.4 GHz REQUIRE MORE
COSTLY INFRASTRUCTURE AND
CUSTOMER PREMISES EQUIPMENT
• DECT AND PHS HAVE TO SACRIFY
VOICE FOR 64-128 Kbps DATA RATES
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
DATA CAPACITY ADVANTAGES
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
DATA CAPACITY ADVANTAGES
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
3-G SERVICES
• COLOURED LCD PHONE AND FIXED WIRELESS DEVICES
AVAILABLE
–
–
–
–
–
–
•
•
•
•
•
CAMERA PHONES
CAMCORDER PHONES
VoD PHONES
GPS PHONES
PUSH TO TALK PHONES
MULTIMESDIA DEVICES FOR FULL TO LIMITED MOBILITY
SYNTHESIZED SOUNDS
MP3
USB CONNECTIVITY
SMS, EMS AND MMS
INTERNET BROWSING
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
HANDSET/FWT AVAILABILITY
• FWTs MADE BY AUDIOVOX, AXESSTEL,
HUAWEI, HYUNDAI-KURITEL,
MOTOROLLA, LG etc
etc……………………………….
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
Handset
– Model similar to
mobile phones viz.
Huawei ETS388
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
FWT
–Model similar to regular phone
Huawei ETS2000
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad
WLL Technologies by Market Segment
26 June 2007
Dr IZHAR-UL-HAQ
CIIT, Islamabad