Wireless Standards-3G and Beyond

8/8/2019 Wireless Standards-3G and Beyond

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Dr. Shahid Khattak 1

Department of Electrical Engineering EE

Wireless Standards : 3G and beyond

Dr. Shahid Khattak

CIIT Abbottabad


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Contents

Cellular Phone Standards

1st Generation

2nd Generation

3rd Generation WCDMA

WiMAX and LTE

Wireless Local Area Networks


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Wireless Evolution


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1st Generation Analog SystemsCellular Phone Standards

30 KHz

30 KHz

30 KHz

30 KHz

30 KHz

30 KHz

30 KHz

30 KHzF

reque

ncy

FDMA Frequency Division Multiple Access


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First-generation (1G) analog

Deployed in the 1980s.

Still in use.

Advanced Mobile Phone System (AMPS)

developed by Bell Labs in the 1970s

first used commercially in the US in 1983.

Adopted by many other countries.

narrowband AMPS (N-AMPS), with one third the bandwidth of

regular AMPS Operating Frequency 824-894 MHz.


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NTT

Deployed in Japan in 1979 with the NTT

Based on AMPS,

Higher Operating frequency 870-940MHz Slightly lower bandwidth.


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Total Access Communication System (TACS).

Developed in Europe

Higher operating frequency than AMPS 890-960MHz

Lower bandwidth channels than AMPS. It was deployed in the U.K., Europe as well as

outside Europe.

ETACS:

The frequency range extended-more channels





Total Access Communication System (TACS). JTACSA

Deployed in Japan in 1989

Higher capacity than the NTT system. Operates at a higher frequency than TACS

bandwidth-efficient version called NTACS-occupy

half the bandwidth


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1st Generation Analog Systems (SUMMARY)Cellular Phone Standards

1NTT also operated in several other frequency bands around 900 MHz.

2RC2000 also operated in several other frequency bands around 200 MHz.




2nd Generation Digital SystemsCellular Phone Standards

GSM(Global System for Mobile Comms) 1982-Groupe Special Mobile (GSM)

develop a uniform digital cellular standard for all of Europe

deployed in the early 1990s

Used in about 66 % of the worlds cell phones more than 470 GSM operators

In 172 countries supporting over a billion users.

As the GSM standard became more global, the

meaning of the acronym was changed to the GlobalSystem for Mobile Communications.





GSM(Global System for Mobile Comms) The TACS spectrum was allocated for GSM

facilitate roaming between countries

1989-GSM specification was finalized

the system was launched in 1991

It uses TDMA combined

Slow FH to combat out-of-cell interference.

CC and parity check codes along with interleaving is

used for error correction and detection. Equalizer




GSM (Global System for Mobile Comms)

F

reque

ncy

Time

200 KHz

200 KHz

200 KHz

200 KHz

One timeslot = 0.577 ms One TDMA frame = 8 timeslots





IS-136 (USA) 1992 the IS-54 digital cellular standard was finalized Commercial deployment in 1994. Same channel spacing, 30 KHz, as AMPS

facilitate the analog to digital transition TDMA multiple access scheme

improve handoff control signaling

Improved over time into the IS-136 standard, uses parity check codes, CC, interleaving, and

equalization.





IS-95 or IS-95a Proposed by Qualcomm in the early 1990s

Finalized in 1993

Deployed commercially as cdmaOne in 1995 Compatible with AMPS

Based on CDMA

all users are superimposed on top of each other with

spreading codes that can separate out the users at the

receiver




CDMA





IS-95 or IS-95a Chip rate =1.2288 Mchips/s

Spreading factor of 128(UL/DL)

Spreading process spread spectrum modulation Coding

A parity check code for error detection,


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IS-95 or IS-95a Downlink

rate 1/2 cc and interleaved modulated by one of 64 orthogonal spreading sequences

(Walsh functions)

Synchronized scrambling sequence unique to each cellsuperimposed on top of the Walsh function reduce interference between cells. requires synchronization between base stations.

Uplink

rate 1/3 cc with interleaving, modulation by an orthogonal Walsh function modulation by a nonorthogonal user/base station specific

scrambling code power control to avoid the near-far problem


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IS-95 or IS-95a 3-finger RAKE receiver

Diversity

Compensate for ISI

Soft handoff (SHO)

A mobile maintains a connection to both the new and old

base stations during handoff and combines their signals


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IS-95 or IS-95a Advantages

No need for frequency planning,

SHO capabilities,

No hard limit on the number of users in the system

Relative merits of the IS-54 and IS-95 standards

Initial claims that IS-95 could achieve 20 times the capacity

of AMPS whereas IS-54 could only achieve 3 times this

capacity. In the end, both achieve equivalent gains


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Personal Digital Cellular (PDC) standard Japan

Established in 1991

deployed in 1994

IS 136-25 KHz voice channels

Compatible with analog systems.

operates in 900 MHz and 1500 MHz frequencybands


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2nd Generation Analog Systems (SUMMARY)Cellular Phone Standards


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Evolution of 2nd GenerationCellular Phone Standards

In the late 1990s 2G systems evolved in two directions: they were ported to higher frequencies they were modified to support data services

In 1994 the FCC (US) began auctioning spectrum

Personal Comm. Sys (PCS) band at 1.9 GHz Operators in this band could adopt any standard.

Different standards Nationwide roaming with a single phone difficult.

GSM systems operating in the PCS band-PCS 1900

Europe-additional spectrum at 1.8 GHz GSM 1800 or DCS 1800 (for Digital Cellular System) Allow overlays of macrocells and microcells.


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Incorporating data services in addition to voice 2.5G High Speed Circuit Switched Data (HSCSD)

Up to 4 consecutive timeslots to be assigned to a single user A maximum transmission rate of up to 57.6 Kbps.

General Packet Radio Service (GPRS).

PS data layered on top of the CS voice. Data rate of 171.2 Kbps is possible when all 8 timeslots of a

GSM frame are allocated to a single user.

Enhanced Data rates for GSM Evolution (EDGE). Variable-rate modulation and coding,

data rates up to 384 Kbps bit rate of 48-69.2 Kbps per timeslot

GPRS and EDGE are compatible with IS-136 as well asGSM


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IS-95b standard Assigning multiple orthogonal Walsh functions to a

single user.

A maximum of 8 data channels can be assigned to a user

Theoretic maximum data rate of 115.2 Kbps

in practice only about 64 Kbps is achieved.


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Evolution of 2nd Generation (SUMMARY)Cellular Phone Standards

1997 2000 2003 2003+

GSM

GPRS

EDGE

UMTS

9.6 kbps

115 kbps

384 kbps

2 Mbps

GSM evolution 3G



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3Generation Wireless System


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3rd Generation SystemsCellular Phone Standards

ITU in the late 1990s to formulate a plan for 3G DigitalCellular System a single global frequency band A single standard

Named International Mobile Telephone 2000 (IMT-2000)

standard voice services, Mbps data rates for

broadband Internet access interactive gaming

high quality audio and video entertainment.


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IMT2000 Vision

Satellite

MacrocellMicrocell

UrbanIn-Building

Picocell

Global

Suburban

Basic Terminal

PDA Terminal

Audio/Visual Terminal


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No Agreement on a single standard two competing standards:

Cdma2000

compatible with cdmaOne

supported by the 3GPP2

wideband CDMA (W-CDMA)

compatible with GSM and IS-136

supported by the 3GPP1

Both use CDMA with power control and RAKE Rx

Detailed specification details are different. cdma2000 and W-CDMA are not compatible, so a

phone must be dual-mode


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The cdma2000 standard builds on cdmaOne

The core of the cdma2000 standard is refered to

cdma2000 1X or cdma2000 1XRTT

the radio transmission technology (RTT) operates in one

pair of 1.25 MHz radio channels

doubles the voice capacity of cdmaOne systems

provides high-speed data services

projected peak rates of around 300 Kbps

actual rates of around 144 Kbps


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The cdma2000 standard evolutions of cdma2000 to provide high data rates (HDR) above 1 Mbps: cdma2000 1XEV-DO (Data Only),

separate 1.25 MHz dedicated high-speed data channel downlink data rates up to 3 Mbp uplink data rates up to 1.8 Mbps

Cdma2000 1XEV-DV (Data and Voice), to support up to 4.8 Mbps data rates voice users,

1XRTT data users, and 1XEV-DO data users, all within thesame radio channel.

Cdma2000 3X. aggregate three 1.25 MHz channel into one 3.75 MHz

channel.


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W-CDMA Universal Mobile TelecommunicationsSystem (UMTS) 3G successor to GSM also used in the Japanese FOMA and J-Phone 3G

systems. Same W-CDMA link layer protocol (air interface) different protocol for routing and speech etc

peak rates of up to 2.4 Mbps typical rates anticipated in the 384 Kbps range. 5 MHz channels, enhancement to W-CDMA

High Speed Data Packet Access (HSDPA)


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TD-SCDMA, A third 3G standard,

in China

unlikely to be adopted elsewhere.

TD-SCDMA and the other 3G standards is its use of

TDD instead of FDD uplink/downlink signaling.


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3rd Generation Systems (SUMMARY)Cellular Phone Standards


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Migration to 3G


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Time line for UMTS-CDMA2000


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UMTS Releases

Release 99: WCDMA Release 5: HSDPA

Release 6: HSUPA

Combined HSDPA and HSUPA is called HSPA. Release 7 MIMO


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UMTS/WCDMA Bandwidth



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CDMA Basics


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Universal Frequency Reuse

Orthogonal Variable Spreading Factor


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Orthogonal Variable Spreading Factor

Codes (OVSF codes)


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OVSF Code Useage


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Scrambling Codes- Pseudo Random Code


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Generating Gold Codes


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Cross Correlation Properties


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Scrambling Codes


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Physical Layer Procedures

Coding Convolution codes

Interleaving

Mapping Data onto physical Channels Spreading using OVSF Channel Codes

PN Scrambling

QPSK Modulation


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Spreading and Scrambling UL


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QPSK Modulation and Pulse Shaping


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Power Control

S f


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Soft Handover

S f H d


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Softer Handover

H d H d


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Hard Handover



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WCDMA Evolution

Rel.5 HSDPA High Speed Downlink Packet Access

Rel.6 Enhanced Uplink HSUPA

High Speed Uplink Packet Access

Rel.7 MIMO

M ti ti d O i


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Motivation and Overview

Data oriented broadband services requires highdata rate

Radio spectrum is an expensive and scarceresource this demands an increase in spectral efficiency.

S t l Effi i


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Spectral Efficiency

Spectral efficiency:

The amount of information that can be transmitted

over a given bandwidth in a specific communication

system. It is a measure of how efficiently a limited frequency

spectrum is utilized by the physical layerprotocol, and

sometimes by the media access control .

S t t l ffi i
http://en.wikipedia.org/wiki/Bandwidth_(signal_processing)http://en.wikipedia.org/wiki/Physical_layerhttp://en.wikipedia.org/wiki/Media_access_controlhttp://en.wikipedia.org/wiki/Media_access_controlhttp://en.wikipedia.org/wiki/Physical_layerhttp://en.wikipedia.org/wiki/Bandwidth_(signal_processing)http://en.wikipedia.org/wiki/Media_access_controlhttp://en.wikipedia.org/wiki/Physical_layerhttp://en.wikipedia.org/wiki/Bandwidth_(signal_processing)


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System spectral efficiency

Defined as the maximum throughput orgoodput,summed over all users in the system, divided by the

channel bandwidth.

It is a measure of the quantity of users or services that

can be simultaneously supported by a limited radiofrequency bandwidth in a defined geographic area.

bit/s/Hz/cell, or bit/s/Hz/site.

affected by

the single user transmission technique

multiple access schemes

radio resource management techniques.

WCDMA Rel. 5 (HSDPA)
http://en.wikipedia.org/wiki/Throughputhttp://en.wikipedia.org/wiki/Goodputhttp://en.wikipedia.org/wiki/Cell_sitehttp://en.wikipedia.org/wiki/Multiple_accesshttp://en.wikipedia.org/wiki/Radio_resource_managementhttp://en.wikipedia.org/wiki/Radio_resource_managementhttp://en.wikipedia.org/wiki/Multiple_accesshttp://en.wikipedia.org/wiki/Cell_sitehttp://en.wikipedia.org/wiki/Goodputhttp://en.wikipedia.org/wiki/Throughputhttp://en.wikipedia.org/wiki/Radio_resource_managementhttp://en.wikipedia.org/wiki/Multiple_accesshttp://en.wikipedia.org/wiki/Cell_sitehttp://en.wikipedia.org/wiki/Goodputhttp://en.wikipedia.org/wiki/Throughput


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Objectives

To provide spectrally-efficient downlink packet access for

packet data services (3 times over Rel.99)

Improvement of system capacity

Improvement of user throughput Improvement of peak data rates (up to 14.4 Mbit/s)

To reduce packet latency

Offer faster error-free medium for application protocols

such as TCP/IP Improved round trip time.

WCDMA Rel.5 (HSDPA)


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Radio resources dynamically shared among

multiple users in time & code domain

New Transport channel type using

Fixed spreading factor of 16 Up to 15 parallel codes multi-code transmission

( )

Shared Channel Transmission



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Attempt to schedule users during constructive-fades

Takes advantage of instantaneous good channel

conditions to users

Downlink channel quality reported by mobile (CQI)

Low latency required Scheduling of users on 2ms time basis

Scheduling performed at Node B

( )

Fast Channel dependent Packet Scheduling

DLChannel

Quality

Scheduler decision

Time

2ms

User 2

User 3

User 1

WCDMA Rel.5 (HSDPA)


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Fast Link Adaptation

Adjust transmission parameters to match instantaneouschannel conditions Path loss, Shadowing, Interference variation, multi-path fading

What Parameters are adapted? Encoding rates A range of coding rates are supported by the

specification (0.14 to 0.89)

Modulation scheme QPSK16QAM

16QAM more sensitive to interference

Transmit power

Number of channelization codes

QPSK

16QAM

WCDMA Rel.5 (HSDPA)


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Fast Hybrid ARQ with Soft Combining

Fast re-transmissions of erroneous packetsprocessed at the Node B (Base Station) with softcombining in the terminal Reduced round trip delay

More effective error correction than standard ARQ Two schemes

Chase Combining

Incremental Redundancy


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WCDMA Rel6 (HSUPA)


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WCDMA e 6 ( SU )Enhanced Uplink ( 2 R99 Capacity)

HSDPA

The shared resource locatedat NodeB transmission power

code space

The scheduler and the Tx.buffers are located in nodeB.

Tx. channels are orthogonal.

HSUPA

The shared resource is the allowed uplink interference

depends on the transmissionpower of UEs.

The scheduler is located in theNodeB while the data buffersare distributed in the UEs. UEs need to signal buffer

status information to the

scheduler. Tx is inherently non-orthogonal, and subject tointra-cell interference. Requires Fast power control

Similar technologies are used both for HSUPA with following differences:

WCDMA Rel6 (HSUPA)


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( )Enhanced Uplink Differences Cont.

HSDPA

Constant transmission power

with rate adaptation is used.

Soft handover is not used

requires additional resources

is cumbersome as it implies

power control by multiple cells

Higher-order modulation is

used as channelization codes

are shared,

trades power efficiency for

bandwidth efficiency

HSUPA

Power offset is used to control

data rate.

Soft handover is supported as

it provides diversity

Channelization codes between

users are not shared

higher-order modulation is

less useful

WCDMA Rel.7


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MIMO

MIMO is introduced to increase the peak data rates

through multi-stream transmission.

Strictly speaking, MIMO, implies use of multiple

antennas at both transmitter and receiver.

Diversity gain

SINR at the receiver.

Spatial multiplexing (2 streams)

to improve the end-user throughput and an increased system

throughput.

Requires high carrier-to-interference ratio.

applicable in smaller cells or close to the base station

3G Evolution


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3G Evolution

[3G Evolution: HSPA and LTE for Mobile Broadband]



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Long Term Evolution (LTE)

3GPP/2



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g ( )Design Targets

LTE targets more complex spectrum situations and hasfewer restrictions on backwards compatibility.

When BW=20MHz, downlink and uplink peak data-rate

requirements are 100 Mbit/s and 50 Mbit/s, respectively.

LTE should support at least 200 mobile terminals in theactive state when operating in 5 MHz.



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g ( )Why OFDM?

More robust to frequency-selective fading attractive for the downlink.

Provides access to the frequency domain

time-frequency resource is dynamically sharedbetween users.

Flexible bandwidth allocations

Provides orthogonality between users within a

cell in both uplink and downlink.

LTE Phy


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LTE Phy.

Modulation QPSK, 16QAM, 64QAM Inter-cell interference coordination

taking inter-cell interference into account.

Multiple antenna support transmit and receive diversity

Spatial multiplexing

Spectrum flexibility both paired andunpaired spectrum ability to operate in a wide range of frequency bands, from

450MHz 2.6 GHz.

Bandwidth flexibility Fast Scheduling

Every 1 ms the granularity in the frequency domain is 180 kHz.

Dealing with Interference


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Change in Paradigm

1st/2nd generation 3rd generation 4th generation

Interference

avoidance through

high reuse factors

Interferenceshaping

andexploitation

throughdistributed

MIMOandrelaying

Interference

suppression through

clasical MIMO

Interference

avoidance through

high reuse factors

Interference

suppression through

clasical MIMO

LTE Advanced?? (BS Cooperation)


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LTE Advanced?? (BS Cooperation)

Core Network

ri

ui

MT

BS

CU

Base Stations (BS)Different Locations

RF Front End

Central Unit (CU)

Joint Detection andDecoding

Data FlowQuantized Rx. Signal from

BS to CU.

Advantages Improved SINR

Reduced Agg. Tx. Power

Increased Capacity

Related Work Hanly 93

Wyner 94

Shamai 97

Paulraj 2002

Baier 2001-2005

Andrews 2003

Weber 2006-08



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Wireless LANs



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802.11 standard, released in 1997

occupies 83.5 MHz of bandwidth

in the unlicensed 2.4 GHz frequency band.

PSK modulation with FHSS or DSSS.

Data rates up to 2 Mbps are supported, with

CSMA/CA used for random access



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802.11b standard Proposed in 1999

operating in the same 2.4 GHz band

using only DSSS.

uses variable-rate modulation and coding,

with BPSK or QPSK for modulation

Channel coding via either Barker sequences or

Complementary Code Keying (CCK).



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802.11b standard, maximum channel rate of 11 Mbps,

with a maximum user data rate of around 1.6 Mbps.

The transmission range is 100 m.

The network architecture is normally star This standard has been widely deployed and used,

with manufacturers integrating 802.11b wireless LANcards into many laptop computers.



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The 802.11a standard finalized in 1999

occupies 300 MHz of spectrum in 5 GHz NII band.

the 300 MHz of bandwidth is segmented into three

100 MHz subbands: a lower band from 5.15-5.25 GHz,

a middle band from 5.25-5.35 GHz,

and an upper band from 5.725-5.825 GHz.

Channels are spaced 20 MHz apart, on the outer edges of the lower and middle

bands-spaced 30 MHz apart.



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The 802.11a standard Three maximum transmit power levels are specified: 40 mW for the lower band, (indoor) 200 mW for the middle band, (indoor/outdoor) 800 mW for the upper band.

Variable-rate modulation and coding is used on eachchannel: BPSK, QPSK, 16QAM, and 64QAM,

convolutional code

rate varies over 1/2, 2/3, and 3/4. a maximum data rate per channel of 54 Mbps. 802.11a uses OFDM



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The 802.11g standard, finalized in 2003, attempts to combine the best of 802.11a and

802.11b, with data rates of up to 54 Mbps in the 2.5 GHz band

for greater range. The standard is backwards compatible with 802.11b However, 802.11g uses the OFDM, modulation, and

coding schemes of 802.11a. Access points and wireless LAN cards are available

with all three standards to avoid incompatibilities. The 802.11a/b/g family of standards are collectively

refered to as Wi-Fi, for wireless fidelity.

Wireless Local Area NetworksC ll l Ph St d d


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WiMAXC S


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A potential competitor to the 802.11 standardsas well as cellular systems is the IEEE 802.16standard called WiMAX.

This standard promises broadband wireless

access data rates on the order of 40 Mbps for fixed users

15 Mbps for mobile users, with a range of severalkilometers.

WiMAX


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WiMAX

The IEEE 802.16 Spectrum

Originally between 10 GHz and 66 GHz.

Extended to include the 2-11 GHz range.

two standards.

Fixed WiMax or 802.16-2004(d).

Mobile WiMax or 802.16e,

WiMAX


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WiMAX

802.16 spectrum ranges above 10 GHz (specifically 10 GHz

to 66 GHz)

orthogonal frequency division multiplexing (OFDM)

wide channels, greater than 10 MHz in size.

WiMAX


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802.16a spectrum ranges of 2 GHz to 11 GHz.

addressed both licensed and unlicensed ranges

also incorporated NLOS capability.

The European HiperMAN standard is supported

Support for both TDD and FDD

both half duplex and full duplex data transmission in

case of FDD

Ethernet, ATM or IP are supported.

WiMAX


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802.16c deals mostly with updates in the 10 GHz to 66 GHz

range.

issues such as performance evaluation, testing anddetailed system profiling.

the system profile methodology evolved to define

what would be mandatory features to ensureinteroperability

what would be optional features. Optional elements

allow vendors to differentiate their products by price,functionality and market niche.

WiMAX


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802.16-2004(d) All of the Fixed WiMax standards mentioned abovehave been rolled into 802.16-2004:

supports both TDD and FDD. theoretical effective data rate is around 70 Mbps,

although real world performance will probably topout around 40 Mbps.


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