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Introduction

What is WLL?
- WLL is a system that connects subscribers to the local telephone station wirelessly.
Systems WLL is based on:
Cellular
Satellite (specific and adjunct)
Microcellular
Other names
Radio In The Loop (RITL)
Fixed-Radio Access (FRA).

Presented By:
Panos Tzanos
Vladimeros Vladimerou
Derek Starr

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Definition
What is WLL?
- WLL is a system that connects subscribers to the local telephone station wirelessly.
 Systems WLL is based on:
– Cellular
– Satellite (specific and adjunct)
– Microcellular
 Other names
– Radio In The Loop (RITL)
– Fixed-Radio Access (FRA).
 A general WLL setup
WLL services
 Desirable:
– Wireless feature should be transparent
– Wireline Custom features
 Other:
– Business related
» Hunt groups,
» Call transfers
» Conference calling
– Calling cards, coin phones
– V.29 (9600bps)
– ISDN (64kbps)
WLL should provide…
 Toll-quality service
 Expand from a central office to about 5 miles
 Low license cost
 Subscriber costs equivalent or better than copper
 Ideas for U.S. market
 Supplement Copper Lines
– Easier third telephone line
– Data service
 Fixed Mobile Users
– Take phone wherever you want / charged on 2 levels
– “home” could mean neighborhood
– Charged regular mobile rate if you’re on the road
Cost Considerations
 Situations “made” for WLL
 Environments where 3rd line is degraded might be cheaper to go wireless
 Where it’s impossible to lay copper (3rd world, small islands)
 Business parks, industrial areas
 Speedy deployment, stop gap application till wireline is in
– 90-120 days for activation
Developed vs. Developing
Developed: Wireline service
– Firmly established, cellular penetration is relatively high
– Incumbent operator would use it to install 2nd, 3rd lines, coverage to rural areas
– 2nd or 3rd competitive operator deploy it for fast & cost effective deployment
– Quick way to establish market presence
– cellular complement to their offerings
Developed vs. Developing
 Developing
– Quick & easy to deploy in countries with little copper line service, so as to accommodate people on enormous waiting lists for basic service
– Low maintenance costs
– Allows more competition in provider market
 Examples
 UK
– 150 PTOs have licenses for wireless
– Focus on regional networks
– WLL Commercial services
» Ionica, Atlantic Telecom, Scottish Telecom
 Poland
– Most exciting market in eastern Europe
– Local loop is the bottleneck
– 150,000 WLL lines since 1996 (15% of new)
– Ericsson, Motorola contracts
Connection Setup
 Important Results of Fixed to Fixed Propagation in WLLs
 Signal channel is not a Rayleigh fading channel:
– Power control algorithms are simpler and can be utilized more effectively
 Channel Randomness is lost:
– Makes analysis difficult
 Pathloss exponent is considerably smaller (Why?):
– 20dB/dec compared to 40dB/dec
– Decreases cell capacity
– Allows for larger coverage area
 No handoffs necessary:
– Decreases hardware costs and system complexity
– Increases quality of service through accurate traffic predictions
 Allows usage of directional antennas:
– Can greatly reduce interference and increase cell capacity
 In-Cell Interference (CDMA)
 I = (Nh – 1)aS » NhaS
a = voice activity factor
Nh = total # of houses
S = power received at cell site from every house
Out-of-Cell Interference
 Pathloss: 20dB/dec as opposed to 40dB/dec
Þ need to take in account more tiers
 Only from houses whose antennas are directed at the center cell base station
Interference from Another Cell
 Blue area is region of interferers for C
 It is Not a perfect pie shape
 If w = (1/2)*(antenna width)
(in radians)
 W = w+2sin-1((R/D)sin(w/2))
 If w<<1 and R<<D:
W = w (1+(R/D))
is the “pie” arc length
 Per-Tier Interference
 Integration over W and all the cells at tier n yields:
In = [aNhSw/(3sqrt(3))][1/n]
for n>4
 Interference is proportional to antenna width w and inversely proportional to the tier number.
 Decreasing the antenna width can greatly reduce interference.
 As the number of tiers approaches infinity, so does the total interference. Therefore, system capacity is a function of the total number of tiers in the system.
Capacity comparison for 5 MHz spectrum allocation
 Comparison
Examples of services provided
 Marconi WipLL (wireless IP local loop)
– Based on Frequency hopping CDMA
– Internet Protocol 64kbps to 2.4Mbps rates Committed Information Rate or best effort service
 Lucent WSS (wireless subscriber system)
– 800 to 5000 subscribers per switch
– Uses FDMA/FDD 12 Km to 40Km coverage
 GoodWin WLL
– DECT standards
– 9.6 kbps rate
– Specified conditions -5°С...+55°С, 20...75% humidity
Future of WLL / Overview
 Depends on
– economic development
– existing infrastructure of a region
 Offers
– market competition
– quick deployment
– relatively reliable service at low costs

Presented By:
PANCHAL SHRUTI
PATEL BHUMI

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ABSTRACT
The term “Wireless” has come to mean no broadcast communication, usually between individual who very often use portable or mobile equipment. Wireless communication is the fastest-growing part of the very dynamic field of electronic communication. It is an area with many jobs that go unfilled due to a shortage of knowledgeable people. Wireless telecommunication began only a little later than the wired.
The advantages of wireless communication are: Completes the access technology portfolio, Goes where cable and fiber cannot, Involves reduced time to revenue and Provides broadband access extension.
In the telephone networks, the circuit between the subscriber's equipment (e.g. telephone set) and the local exchange in the central once is called the and subscriber loop' or &local loop'. Traditionally, the copper wire has been used as the medium for local loop to provide voice and voice-band data services Wireless local loop provides two-ways a telephone system where subscribers are connected to the Public Switched Telephone Network (PSTN) using radio signals rather than copper wire for the part of a network or for the all of the connection between the subscribers & the switch.
The communication for WLL is by signal transmission that is Point-to-Point. These signals travels thought the air via a microwave platform instead of through cables made of fiber or copper. Fixed wireless communication does not require feeds from satellite or from the local phone service. This reduces the cost and time for planning miles of cable.
The architecture of WLL consist of major components: the wireless access network unit (WANU), the wireless access subscriber unit (WASU), and the switching function (SF).
The technical requirements of WLL are: Communication quality, Short construction period, Absence of interference with other, Wireless systems and High traffic volume.
WLL will be Implemented across Five Categories of Wireless Technology are: Analog cellular, Digital cellular, Personal communication service (PSN)/Personal communication network (PCN), Cordless telephone 2nd generation (CT-2)/Digital European cordless telecommunication and Proprietary implementation.
Advantages of WLL are: fast development, low construction cost, low operation and maintenance cost, customer connection cost, high bandwidth service provision, lower network extension costs and high system capacity.
CHAPTER 1: INTRODUCTION TO WIRELESS COMMUNICATION
1.1 WHAT IS WIRELESS COMMUNICATION:-
Wireless Communication by radio, through ultrasound and infrared light are also used occasionally. The term “Wireless” has come to mean no broadcast communication, usually between individual who very often use portable or mobile equipment. The term rather vague, and there are certainly broad line applications that are called wireless without falling exactly into the above application.
Wireless communication is the fastest-growing part of the very dynamic field of electronic communication. It is an area with many jobs that go unfilled due to a shortage of knowledgeable people.
1.2 HISTORY OF WIRELESS COMMUNICATION:-
Wireless telecommunication began only a little later than the wired. Morse’s telegraph (1837) and Bell’s telephone (1876) were soon followed by Hert’s first experiment with radio (1887). Hert’s system was a laboratory curiosity, but Marconi communicated across the English Channel in 1899 and across the Atlantic Ocean in 1901. Then successes led to the widespread use of radio for ship-to-shore communication using Morse code.
Early wireless system used crude, through often quite powerful, speaks gap transmission and was suited only for radiotelegraphy. The invention of the triode vacuum tube by De Forest in 1906 allowed for the modulation of a continuous-wave signal and made voice transmission practical. Commersial radio broadcasting in both the United States and Canada began in 1920.Twoway police radio, with the equipment occupying most of the car trunk began in mid-1930s.
After the end of World Wore ||, two systems were developed that presaged modern wireless communication. AT & T introduced its Improved Mobile Telephone Service (IMTS) in 1946.Pagers were introduced in 1962. The world’s first cellular radio service was installed in Japan in 1979, followed in 1983 by North American services.
1.3 ADVANTAGES OF WIRELESS COMMUNICATION:
20-7
The following list summarizes the main benefits of using wireless technologies:
1.3.1 Completes the access technology portfolio—Customers commonly use more than one access technology to service various parts of their network and during the migration phase of their networks, when upgrading occurs on a scheduled basis. Wireless enables a fully comprehensive access technology portfolio to work with existing dial, cable, and DSL technologies.
1.3.2 Goes where cable and fiber cannot—the inherent nature of wireless is that it doesn’t require wires or lines to accommodate the data/voice/video pipeline. As such, the system will carry information across geographical areas that are prohibitive in terms of distance, cost, access, or time. It also sidesteps the numerous issues of ILEC coloration.
Although paying fees for access to elevated areas such as masts, towers, and building tops is not unusual, these fees, the associated logistics, and contractual agreements are often minimal compared to the costs of trenching cable.
1.3.3 Involves reduced time to revenue—Companies can generate revenue in less time through the deployment of wireless solutions than with comparable access technologies because a wireless system can be assembled and brought online in as little as two to three hours. This technology enables service providers to sell access without having to wait for cable-trenching operations to complete or for incumbent providers to provide access or backhaul.
1.3.4 Provides broadband access extension—Wireless commonly both competes with and complements existing broadband access. Wireless technologies play a key role in extending the reach of cable, fiber, and DSL markets, and it does so quickly and reliably. It also commonly provides a competitive alternative to broadband wire line or provides access in geographies that don’t qualify for loop access.