4G Wireless Technology

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Seminar Report

Seminar Report

On

On

4G

4G

WIRELESS

WIRELESS

SYSTEMS

SYSTEMS

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Er.

Er. Rajiv Rajiv Kamboj Kamboj RajatRajat

Baweja Baweja (Lect.

(Lect. ECE ECE Deptt.) Deptt.) RollRoll

No.: 2106075 No.: 2106075

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(EC (EC E Final Yr.) E Final Yr.)

ABSTRACT

ABSTRACT

Fourth generation wireless system is a packet switched wireless system with Fourth generation wireless system is a packet switched wireless system with wide area coverage and high throughput. It is designed to be cost effective and wide area coverage and high throughput. It is designed to be cost effective and to provide high spectral efficiency. The 4G wireless uses Orthogonal Frequency to provide high spectral efficiency. The 4G wireless uses Orthogonal Frequency Divi

Division Multiplesion Multiplexing xing (OF(OFDM), DM), UltrUltra a WidWide e RadRadio io Band (UWB) Band (UWB) and and MilliMillimetmeter er  wireless. Data rate of 20mbps is employed. Mobile speed will be up

wireless. Data rate of 20mbps is employed. Mobile speed will be up to 200km/hr.to 200km/hr. The high performance is achieved by the use of long term channel prediction, in The high performance is achieved by the use of long term channel prediction, in both time and frequency, scheduling among users and smart antennas combined both time and frequency, scheduling among users and smart antennas combined with adaptive modulation and power control. Frequency band is 2-8 GHz. it gives with adaptive modulation and power control. Frequency band is 2-8 GHz. it gives the ability for world wide roaming to access cell anywhere.

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Introduction

Introduction

4G

4G (also known as(also known as Beyond 3GBeyond 3G), an abbreviation for ), an abbreviation for  Fourth-GenerationFourth-Generation , is a, is a term used to

term used to describdescribe the e the next complete evolution innext complete evolution in wireless communicationswireless communications. It. It

is a successor to

is a successor to 3G3G andand 2G2G standards, with the aim to provide a wide range of standards, with the aim to provide a wide range of  data rates up to

data rates up to ultra-broadbandultra-broadband (gigabit-speed) Internet access to mobile as well(gigabit-speed) Internet access to mobile as well as stationary users.

as stationary users. As

As ththe e sesecocond nd gegenerneratiation on wawas s a a tottotal al rereplaplacecemement nt of of ththe e firfirst st gegeneneratrationion networks and handsets; and the third generation was a total replacement of  networks and handsets; and the third generation was a total replacement of  second generation networks and handsets; so too the fourth generation cannot second generation networks and handsets; so too the fourth generation cannot be

be an an incrincremenemental evolutital evolution on of of currcurrent 3G ent 3G techtechnolonologiesgies, , but rather the but rather the totatotall replacement of the current

replacement of the current 3G3G networks and handsets.networks and handsets.

A 4G system will be able to provide a comprehensive IP solution where voice, A 4G system will be able to provide a comprehensive IP solution where voice, data and streamed multimedia can be given to

data and streamed multimedia can be given to users on an users on an “Anytime“Anytime, Anywhere”, Anywhere” basis, and at higher data rates than previous generations.

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FEATURES:

FEATURES:

1.

1. Support for interactive multimedia, voice, streaming video, Internet, andSupport for interactive multimedia, voice, streaming video, Internet, and other broadband services.

other broadband services.

2.

2. IP based mobile system.IP based mobile system.

3.

3. High speed, high capacity, and low costHigh speed, high capacity, and low cost‐‐per per ‐‐bit.bit.

4.

4. Global access, service portability, and scalable mobile services.Global access, service portability, and scalable mobile services.

5.

5. Seamless switching and a variety of Quality of ServiceSeamless switching and a variety of Quality of Service‐‐driven services.driven services.

6.

6. Better scheduling and callBetter scheduling and call‐‐admissionadmission‐‐control techniquescontrol techniques

7.

7. AdAd‐‐hoc and multihoc and multi‐‐hop networks (the strict delay requirements of voicehop networks (the strict delay requirements of voice make multi

make multi‐‐hop network service a difficult problem)hop network service a difficult problem)

8.

8. Better spectral efficiency.Better spectral efficiency.

9.

9. Seamless network of multiple protocols and air interfaces (since 4G will beSeamless network of multiple protocols and air interfaces (since 4G will be all

all‐‐IP, look for 4G systems to be compatible with all common networkIP, look for 4G systems to be compatible with all common network technologies, including 802.11, WCDMA, Bluetooth, and Hyper LAN). technologies, including 802.11, WCDMA, Bluetooth, and Hyper LAN).

10.

10. An infrastructure to handle preAn infrastructure to handle pre‐‐existing 3G systems along withexisting 3G systems along with ot

otheher r wwirireeleless ss tetechchnonolologgieies, s, sosomme e of of whwhicich h arare e cucurrrrenentltly y unundeder r  development.

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HISTORY:

HISTORY:

The history and evolution of mobile service from the

The history and evolution of mobile service from the 1G(FIRST GENERATION)1G(FIRST GENERATION) to fourth generation are as follows. The process began with the designs in the to fourth generation are as follows. The process began with the designs in the 1970s that have become known as 1G. The earliest systems were implemented 1970s that have become known as 1G. The earliest systems were implemented based on

based on ANALOG TECHNOLOGYANALOG TECHNOLOGY and the basic cellular structure of mobileand the basic cellular structure of mobile com

commumuninicatcationion. . MaMany ny funfundadamementantal l prproboblemlems s wewere re sosolvelved d by by ththese ese eaearlyrly systems. Numerou

systems. Numerous incompatible analog systems were s incompatible analog systems were placed in placed in service aroundservice around the world during the 1980s.

the world during the 1980s. The

The 2G (SECOND GENERATION)2G (SECOND GENERATION) systems designed in the 1980s were stillsystems designed in the 1980s were still used mainly for voice applications but were based on digital technology, including used mainly for voice applications but were based on digital technology, including digital signal processing techniques. These 2G systems provided circuit

digital signal processing techniques. These 2G systems provided circuit ‐‐switchedswitched data communication services at a low speed. The competitive rush to design and data communication services at a low speed. The competitive rush to design and implement digital systems led again to a variety of different and incompatible implement digital systems led again to a variety of different and incompatible standards such as

standards such as GSMGSM (global system mobile),(global system mobile), TDMATDMA (time division multiple(time division multiple access);

access); PDCPDC (per(personasonal l digidigital tal cellcellularular) ) andand CDMACDMA (co(code de dividivisiosion n mulmultipltiplee acce

access)ss).The.These se systsystems ems operoperate ate natnationwionwide ide or or inteinternarnationtionally ally and and are are todatoday’sy’s mainstream systems, although the data rate for users in these system is very mainstream systems, although the data rate for users in these system is very limited.

limited. Dur

During ing ththe e 19199090’s ’s the the nenextxt, , or or  3G(THIR3G(THIRD D GENETGENETRATIONRATION)), , mobimobile le syssystem,tem, whic

which h wouwould ld elimeliminatinate e prevprevious ious incoincompampatibitibilitilities es and and becbecome ome a a trutruly ly globglobalal system. The 3G system would have higher quality voice channels, as well as system. The 3G system would have higher quality voice channels, as well as broadband data capabilities, up to 2 Mbps.

broadband data capabilities, up to 2 Mbps.

An interim step is being taken between 2G and 3G, the 2.5G. It is basically an An interim step is being taken between 2G and 3G, the 2.5G. It is basically an enhancem

enhancement of ent of the two the two major 2G technologies to provide increased capacity onmajor 2G technologies to provide increased capacity on the

the 2G 2G RF RF (ra(radidio o frfrequequencency) y) s s anand d to to intintroroducduce e hihighegher r ththrouroughghput put for for dadatata ser

servicvice, e, up up to to 38384 4 kbkbpsps. . A A ververy y imimporportantant t aspaspect of ect of 2.2.5G 5G is is ththat at ththe e dadatata channels are optimized for packet data, which introduces access to the Internet channels are optimized for packet data, which introduces access to the Internet

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from

from mobmobile ile devdevicesices, , whewhether ther teletelephophone, ne, PDA PDA (per(personsonal al digidigital tal assassistaistant), nt), or or  la

lapptotopp. . HHoowweveveer, r, tthe he ddeemmaannd d ffor or hhigighher er aacccceess ss ssppeeeed d mmuultltimimeeddiaia co

commmmununicicatatioion n in in totodaday’y’s s sosocicietety, y, whwhicich h grgreaeatltly y dedepependnds s on on cocompmpututer er  communication in digital format, seems unlimited.

communication in digital format, seems unlimited.

According to the historical indication of a generation revolution occurring once a According to the historical indication of a generation revolution occurring once a decade, the present appears to be the right time to begin the research on a 4G decade, the present appears to be the right time to begin the research on a 4G mobile communication system.

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ABOUT 4G:

ABOUT 4G:

This new generation of wireless is intended to complement and replace the 3G This new generation of wireless is intended to complement and replace the 3G systems, perhaps in 5 to 10 years. Accessing information anywhere, anytime, systems, perhaps in 5 to 10 years. Accessing information anywhere, anytime, with a seamless connection to a wide range of information and services, and with a seamless connection to a wide range of information and services, and receiving a large volume of information, data, pictures, video, and so on, are the receiving a large volume of information, data, pictures, video, and so on, are the keys of the 4G infrastructures.

keys of the 4G infrastructures.

The future 4G infrastructures will consist of a set of various networks using IP The future 4G infrastructures will consist of a set of various networks using IP (Internet protocol) as a common protocol so that users are in control because (Internet protocol) as a common protocol so that users are in control because they will be able to choose every application and environment. Based on the they will be able to choose every application and environment. Based on the developing trends of mobile communication, 4G will have broader bandwidth, developing trends of mobile communication, 4G will have broader bandwidth, higher data rate, and smoother and quicker handoff and will focus on ensuring higher data rate, and smoother and quicker handoff and will focus on ensuring seamless service across a multitude of wireless systems and networks. The key seamless service across a multitude of wireless systems and networks. The key co

concncepept t is is inintetegrgratatining g ththe e 4G 4G cacapapabibililitities es wiwith th alall l of of ththe e exexisistiting ng momobibilele technologies through advanced technologies. Application adaptability and being technologies through advanced technologies. Application adaptability and being highly dynamic are the main features of 4G services of interest to users. These highly dynamic are the main features of 4G services of interest to users. These fea

featurtures es memean an serservivices ces can can be be dedelivliverered ed and and be be avavailailablable e to to the the pepersorsonanall preference of different users and support the users traffic, air interfaces, radio preference of different users and support the users traffic, air interfaces, radio environment, and quality of service. Connection with the network applications environment, and quality of service. Connection with the network applications can be transferred into various forms and levels correctly and efficiently.

can be transferred into various forms and levels correctly and efficiently.

The dominant methods of access to this pool of information will be the mobile The dominant methods of access to this pool of information will be the mobile tele

telephonphone, e, PDAPDA, , and and laptlaptop op to to seaseamlesmlessly sly accaccess ess the the voicvoice e comcommunmunicatication,ion, high

high‐‐spespeed ed infoinformarmation tion servserviceices, s, and and enteentertairtainmenment nt brobroadcaadcast st servservicesices. . TheThe fourth generation will encompass all systems from various networks, public to fourth generation will encompass all systems from various networks, public to private; operator 

private; operator ‐‐drdriveiven n brbroaoadbadband nd netnetworworks ks to to perpersosonal nal areareasas; ; anand d ad ad hochoc networks. The 4G systems will interoperate with 2G and 3G systems, as well as networks. The 4G systems will interoperate with 2G and 3G systems, as well as with digital (broadband) broadcasting systems. In addition, 4G systems will be with digital (broadband) broadcasting systems. In addition, 4G systems will be fully IP

fully IP‐‐based wireless Internet. This allbased wireless Internet. This all‐‐encompassing integrated perspectiveencompassing integrated perspective shows the broad range of systems that the fourth generation intends to integrate, shows the broad range of systems that the fourth generation intends to integrate,

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from satellite broadband to high altitude platform to cellular 3G and 3G systems from satellite broadband to high altitude platform to cellular 3G and 3G systems to WLL

to WLL (wireles(wireless local s local loop) and FWA (fixed loop) and FWA (fixed wireless accesswireless access) to ) to WLAN (wirelessWLAN (wireless lo

locacal l ararea ea nenetwtworork) k) anand d PAPAN N (p(perersosonanal l ararea ea nenetwtworork)k),a,all ll wiwith th IP IP as as ththee integrating mechanism. With 4G, a range of new services and models will be integrating mechanism. With 4G, a range of new services and models will be avai

availablable. le. TheThese se serservicevices s and and modmodels els neeneed d to to be be furtfurther examinher examined ed for their for their  interface with the design of 4G systems.

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IMPLEMENTATION USING 4G

IMPLEMENTATION USING 4G

The goal of 4G is to replace the current proliferation of core mobile networks with The goal of 4G is to replace the current proliferation of core mobile networks with a single worldwide core network standard, based on

a single worldwide core network standard, based on IP for IP for control, video, packetcontrol, video, packet data, and voice. This will provide uniform video, voice, and data services to the data, and voice. This will provide uniform video, voice, and data services to the mobile host, based entirely on IP.

mobile host, based entirely on IP.

The objective is to offer seamless multimedia services to users accessing an all The objective is to offer seamless multimedia services to users accessing an all IP

IP‐‐basbased ed ininfrafrastrstructucture ure thrthrougough h heheterterogeogeneneous ous accaccess ess tetechchnolnologogiesies. . IP IP isis assumed to act as an adhesive for providing global connectivity and mobility assumed to act as an adhesive for providing global connectivity and mobility among networks.

among networks. A

An n aalll l IIPP‐‐babasesed d 4G 4G wiwirereleless ss nenetwtworork k hahas s ininhehererent nt adadvavantntagages es ovover er ititss predecessors. It is compatible with, and independent of the underlying radio predecessors. It is compatible with, and independent of the underlying radio access technology. An IP wireless network replaces the old Signaling System 7 access technology. An IP wireless network replaces the old Signaling System 7 (SS7) telecommunications protocol, which is considered massively redundant. (SS7) telecommunications protocol, which is considered massively redundant. This is because SS7 signal transmission consumes a larger part of network This is because SS7 signal transmission consumes a larger part of network bandwidt

bandwidth even when theh even when there is no signalire is no signaling traffic for the sng traffic for the simple imple reason thareason that itt it uses a call setup mechanism to reserve bandwidth, rather time/frequency slots in uses a call setup mechanism to reserve bandwidth, rather time/frequency slots in the radio waves. IP networks, on the other hand, are connectionless and use the the radio waves. IP networks, on the other hand, are connectionless and use the slots only when they have data to send. Hence there is optimum usage of the slots only when they have data to send. Hence there is optimum usage of the available bandwidth. Today, wireless communicatio

available bandwidth. Today, wireless communications ns are heavily are heavily biased towardbiased toward voice, even though studies indicate that growth in wireless data traffic is rising voice, even though studies indicate that growth in wireless data traffic is rising exponentially relative to demand for voice traffic. Because an all IP core layer is exponentially relative to demand for voice traffic. Because an all IP core layer is

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easily scalable, it is ideally suited to meet this challenge. The goal is a merged easily scalable, it is ideally suited to meet this challenge. The goal is a merged data/voice/multimedia network.

data/voice/multimedia network.

TRANSMISSION

TRANSMISSION

An OFDM

An OFDM transmittransmitter accepts data ter accepts data from an IP from an IP network, convertnetwork, converting and ing and encodinencodingg the data prior to modulation. An IFFT (inverse fast Fourier transform) transforms the data prior to modulation. An IFFT (inverse fast Fourier transform) transforms the OFDM signal into an IF analog signal, which is sent to the RF transceiver. the OFDM signal into an IF analog signal, which is sent to the RF transceiver. The

The recreceiveiver er circircuicuit t recrecononstrstructucts s ththe e datdata a by by revreversersing ing ththis is proprocecessss. . WiWithth orthogona

orthogonal l subsub‐‐carriers, the receiver can separate and process each subcarriers, the receiver can separate and process each sub ‐‐carrier carrier  without interference from other sub

without interference from other sub‐‐carriers. More impervious to fading and multicarriers. More impervious to fading and multi‐‐

path delays than other wireless transmission techniques, ODFM provides better  path delays than other wireless transmission techniques, ODFM provides better  link and communication quality.

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Wireless Technologies Used In 4G

Wireless Technologies Used In 4G

1. OFDM 1. OFDM 2. UWB 2. UWB 3. MILLIMETER WIRELESS 3. MILLIMETER WIRELESS 4. SMART ANTENNAS 4. SMART ANTENNAS

5. LONG TERM POWER PREDICTION 5. LONG TERM POWER PREDICTION 6. SHEDULING AMONG USERS

6. SHEDULING AMONG USERS

7. ADAPTIVE MODULATION AND POWER CONTROL 7. ADAPTIVE MODULATION AND POWER CONTROL

1.

1. Orthog

Orthogonal

onal Frequen

Frequency Di

cy Division

vision Multi

Multiplexin

plexing:

g:

OFDM, a form of multi

OFDM, a form of multi‐‐carrier modulation, works by dividing the data stream for carrier modulation, works by dividing the data stream for  transmission at a bandwidth B into N multiple and parallel bit streams, spaced transmission at a bandwidth B into N multiple and parallel bit streams, spaced B/N apart (

B/N apart (Figure)Figure). Each of the parallel bit streams has a much lower bit rate. Each of the parallel bit streams has a much lower bit rate than the original bit stream, but their summation can provide very high data rates. than the original bit stream, but their summation can provide very high data rates. N

N orthorthogonogonal al subsub‐‐carrcarriers modulaiers modulate te the the paraparallel llel bit bit strstreamseams, , whiwhich ch are thenare then summed prior to transmission.

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An OFDM

An OFDM transmittransmitter accepts data ter accepts data from an IP from an IP network, convertnetwork, converting and ing and encodinencodingg the data prior to modulation. An IFFT (inverse fast Fourier transform) transforms the data prior to modulation. An IFFT (inverse fast Fourier transform) transforms the OFDM signal into an IF analog signal, which is sent to the RF transceiver. the OFDM signal into an IF analog signal, which is sent to the RF transceiver. The

The recreceiveiver er circircuicuit t recrecononstrstructucts s ththe e datdata a by by revreversersing ing ththis is proprocecessss. . WiWithth orthogona

orthogonal l subsub‐‐carriers, the receiver can separate and process each subcarriers, the receiver can separate and process each sub ‐‐carrier carrier  without interference from other sub

without interference from other sub‐‐carriers. More impervious to fading and multicarriers. More impervious to fading and multi‐‐

path delays than other wireless transmission techniques, ODFM provides better  path delays than other wireless transmission techniques, ODFM provides better  link and communication quality.

link and communication quality.

2.

2.

Ult

Ultra Wide Band :

ra Wide Band :

A UWB transmitter spreads its signal over a wide portion of the RF spectrum, A UWB transmitter spreads its signal over a wide portion of the RF spectrum, generally 1 GHz wide or more, above 3.1GHz. The FCC has chosen UWB generally 1 GHz wide or more, above 3.1GHz. The FCC has chosen UWB frequencies to minimize interference to other commonly used equipment, such as frequencies to minimize interference to other commonly used equipment, such as televisions and radios. This frequency range also puts UWB equipment above televisions and radios. This frequency range also puts UWB equipment above the 2.4 GHz range of microwave ovens and modern cordless phones, but below the 2.4 GHz range of microwave ovens and modern cordless phones, but below 802.11a wireless Ethernet, which operates at 5 GHz.

802.11a wireless Ethernet, which operates at 5 GHz.

UWB equipment transmits very narrow RF pulses—low power and short pulse UWB equipment transmits very narrow RF pulses—low power and short pulse period means the signal, although of wide bandwidth, falls below the threshold period means the signal, although of wide bandwidth, falls below the threshold detection of most RF receivers. Traditional RF equipment uses an RF carrier to detection of most RF receivers. Traditional RF equipment uses an RF carrier to transmit a modulated signal in the frequency domain, moving the signal from a transmit a modulated signal in the frequency domain, moving the signal from a base band to the carrier frequency the transmitter uses. UWB is

base band to the carrier frequency the transmitter uses. UWB is ʺʺcarrier carrier ‐‐freefreeʺʺ,,

since the technology works by modulating a pulse, on the order of 

since the technology works by modulating a pulse, on the order of 

tens of 

tens of 

microwatts, resulting in a waveform occupying a very wide frequency

microwatts, resulting in a waveform occupying a very wide frequency

domain. The wide bandwidth of a UWB signal is a two

domain. The wide bandwidth of a UWB signal is a two ‐‐edged sword.

edged sword.

The

The si

sign

gnal

al is

is rel

relati

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potential for very high

potential for very high‐‐rate wireless broadband access and speed. On

rate wireless broadband access and speed. On

the other hand, the signal also has the potential to interfere with other 

the other hand, the signal also has the potential to interfere with other 

wireles

wireless

s trans

transmissi

missions. In

ons. In additi

addition, the

on, the low power

low power constr

constraints placed

aints placed

on UWB by the FCC, due to its potential interference with other RF

on UWB by the FCC, due to its potential interference with other RF

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signals, significantly limits the range of UWB equipment (but still makes it a signals, significantly limits the range of UWB equipment (but still makes it a viable LAN technology).

viable LAN technology).

3.

3.

Millimeter Wireless

Millimeter Wireless

::

Usi

Using ng ththe e mimillillimemeter ter ‐‐wawave ve babannd d (a(abobove ve 220 0 GHGHz) z) fofor r wiwirereleless ss seservrvicice e isis par

particticulaularly rly intintereereststinging, , due due to to ththe e avavailailababiliility ty in in ththis is regregion ion of of babandndwidwidthth res

resourourceces s cocommmmittitted ed by by ththe e gogoververnmnmenents ts of of sosome me coucountrntries ies to to ununliclicenensesedd cellular and other wireless applications. If deployed in a 4G system, millimeter  cellular and other wireless applications. If deployed in a 4G system, millimeter  wireless would constitute only one of several frequency bands, with the 5 GHz wireless would constitute only one of several frequency bands, with the 5 GHz band most likely dominant.

band most likely dominant.

4.

4.

Smart Antennas

Smart Antennas

::

A

A smsmarart t anantetenna nna sysystestem m cocompmprisrises es mumultiltiple ple anantentenna na eleelemements nts witwith h sisignagnall processing to automatically optimize the antennas radiation (transmitter) and/or  processing to automatically optimize the antennas radiation (transmitter) and/or  reception (receiver) patterns in response to the signal environment. One smart reception (receiver) patterns in response to the signal environment. One smart ‐‐

antenna variation in particular, MIMO, shows promise in

antenna variation in particular, MIMO, shows promise in 4G systems, particularly4G systems, particularly since the antenna systems at both transmitter and receiver are usually a limiting since the antenna systems at both transmitter and receiver are usually a limiting factor when attempting to support increased data rates.

factor when attempting to support increased data rates. MIMO (Multi

MIMO (Multi‐‐Input MultiInput Multi‐‐Output) is a smart antenna system where ‘smartness’ isOutput) is a smart antenna system where ‘smartness’ is considere

considered at d at both transmitter and the both transmitter and the receiverreceiver. MIMO . MIMO represerepresents spacents space‐‐divisiondivision multiplexing (SDM)—information signals are multiplexed on spatially separated N multiplexing (SDM)—information signals are multiplexed on spatially separated N multiple antennas and received on M antennas.

multiple antennas and received on M antennas. FigureFigure shows a general blockshows a general block di

diagagraram m of of a a MIMIMO MO sysyststemem. . SoSome me sysyststemems s mamay y nonot t ememplploy oy ththe e sisigngnalal‐‐

processing block on the transmitter side. processing block on the transmitter side.

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Multiple antennas at both the transmitter and the receiver provide essentially Multiple antennas at both the transmitter and the receiver provide essentially multiple parallel channels that operate simultaneously on the same frequency multiple parallel channels that operate simultaneously on the same frequency band and at the same time. This results in high spectral efficiencies in a rich band and at the same time. This results in high spectral efficiencies in a rich scattering environment (high multi

scattering environment (high multi‐‐path), since you can transmit multiple datapath), since you can transmit multiple data streams or signals over the channel simultaneously. Field experiments by several streams or signals over the channel simultaneously. Field experiments by several organizations have shown that a MIMO system, combined with adaptive coding organizations have shown that a MIMO system, combined with adaptive coding and modulation, interference cancellation, and beam

and modulation, interference cancellation, and beam‐‐forming technologies, canforming technologies, can boost useful channel capacity by at least an order of magnitude.

boost useful channel capacity by at least an order of magnitude.

5.

5.

Long T

Long Term Po

erm Power P

wer Predict

rediction

ion ::

Ch

Channannels els to to difdifferferenent t momobibile le useusers rs wiwill ll fadfade e inindedepenpendedentlntly. y. If If the the chachannnnelel properties of all users in

properties of all users in a cell can a cell can be predicted a number of milliseconds ahead,be predicted a number of milliseconds ahead, then it would be possible to distribute the transmission load among the users in then it would be possible to distribute the transmission load among the users in an optimal way while fulfilling certain specified constraints on throughput and an optimal way while fulfilling certain specified constraints on throughput and de

delaylays. s. ThThe e chachannennel l timtimee‐‐frequefrequencncy y papattettern rn wiwill ll dedepepend nd on on the the scscattatterieringng environment and on the velocity of the moving terminal.

environment and on the velocity of the moving terminal.

In order to take the advantage the channel variability, we use OFDM system with In order to take the advantage the channel variability, we use OFDM system with spacing between sub carriers such that no inter channel interface occurs for the spacing between sub carriers such that no inter channel interface occurs for the worst case channel scenario (Low coherence bandwidth).A time

worst case channel scenario (Low coherence bandwidth).A time‐‐frequency gridfrequency grid constituting of regions of one time slot and several subcarriers is used such that constituting of regions of one time slot and several subcarriers is used such that the channel is fairly constant over each region. These time

the channel is fairly constant over each region. These time ‐‐frequency regions arefrequency regions are then allocated to the

then allocated to the different users by a different users by a schedulinscheduling algorithm according to someg algorithm according to some criterion.

criterion.

6.

6.

Scheduling among Users

Scheduling among Users

::

To optimize the system throughput, under specified QoS requirements and delay To optimize the system throughput, under specified QoS requirements and delay constraints, scheduling will be used on different levels:

constraints, scheduling will be used on different levels: Amo

Among ng sesectoctors:rs:‐‐IIn n oorrddeer r tto o ccooppe e wwiitth h ccoo‐‐chchannannel el ininterterferferenence ce amamonongg

neighboring sectors in adjacent cells, time slots are allocated according to the neighboring sectors in adjacent cells, time slots are allocated according to the

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tr

trafaffific c loload ad in in eaeach ch sesectctor or .I.Infnforormamatition on on on ththe e trtrafaffific c loload ad is is exexchchanangegedd inf

infreqrequenuently tly via via an an inqinquiruiry y prprococededureure. . In In thithis s waway y the the ininterterferferencence e can can bebe minimized and higher capacity be obtained.

minimized and higher capacity be obtained. Aft

After er an an ininququiry iry to to adadjacjacent ent cecellslls, , the the ininvolvolveved d babase se ststatiations ons dedetertermimine ne ththee allocation of slots to be used by each base station in each sector. The inquiry allocation of slots to be used by each base station in each sector. The inquiry process can also

process can also include synchroninclude synchronization informatioization information to n to align the transmission of align the transmission of  packets at different base stations to further enhance performance.

packets at different base stations to further enhance performance. Among users:

Among users:‐‐Based on the time slot allocation obtained from inquiry process,Based on the time slot allocation obtained from inquiry process,

the user scheduler will distribute time

the user scheduler will distribute time‐‐frequency regions among the users of eachfrequency regions among the users of each sect

sector or basebased d on on thetheir ir currcurrent ent chanchannel nel prepredictdictionsions. . HerHere e diffdifferenerent t degrdegrees ees of of  sophistication can be used to achieve different transmission goals.

sophistication can be used to achieve different transmission goals.

7.

7.

Adaptive modulation and power control

Adaptive modulation and power control

::

In a fading environment and for a highly loaded system there will almost exist In a fading environment and for a highly loaded system there will almost exist users with good channel conditions. Regardless of the choice of criterion, which users with good channel conditions. Regardless of the choice of criterion, which cou

could ld be be eiteither her mamaximximizaizatiotion n of of sysystestem m ththrouroughghput put or or eqequaualizlizatiation on to to ususer er  satisfaction, the modulation format for the scheduled user is selected according satisfaction, the modulation format for the scheduled user is selected according to the predicted signal to noise and interference ratio.

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APPLICATIONS

APPLICATIONS

1

1.. 4

4G

G C

Ca

ar 

With the hype of 3G wireless in the rear view mirror, but the reality of truly mobile With the hype of 3G wireless in the rear view mirror, but the reality of truly mobile broadband data seemingly too far in the future to be visible yet on the information broadband data seemingly too far in the future to be visible yet on the information super highway, it may seem premature to offer a test drive 4G. But the good super highway, it may seem premature to offer a test drive 4G. But the good news is, 4G is finally coming to a showroom near you.

news is, 4G is finally coming to a showroom near you.

2.

2. 4G a

4G and p

nd pub

ubli

lic sa

c safet

fety

y

The

There re arare e swsweepeeping ing chchananges ges taktaking ing plaplace ce in in trtranansposportartatiotion n and and intintelelligligentent highways, generally referred to as “Intelligent Transportation Systems” (ITS). ITS highways, generally referred to as “Intelligent Transportation Systems” (ITS). ITS is

is comcomprisprised ed of of a a numnumber ber of of techtechnolonologiesgies, , inclincludinuding g infoinformarmation tion procprocessessing,ing, comm

communicunicatioations, ns, contcontrol, rol, and and elecelectrontronics. ics. UsinUsing g thesthese e tectechnolhnologieogies s with with our our  transportation systems, and allowing first responders access to them, will help transportation systems, and allowing first responders access to them, will help prevent

prevent ‐‐ or certainly mitigateor certainly mitigate ‐‐ future disasters.future disasters. Comm

Communicunicatioations, ns, and and the the coopcooperaeration tion and and collcollaboaboratiration on it it affoaffords, is rds, is a a keykey element of any effective disaster response. Historically, this has been done with element of any effective disaster response. Historically, this has been done with bulky handheld radios that provide only voice to a team in a common sector. And bulky handheld radios that provide only voice to a team in a common sector. And thi

this s arcarchithitececturture e is is stistill ll celcellulularlar, , wiwith th a a sinsingugular lar popoint int of of fafailuilurere, , bebecaucause se allall transmissions to a given cell must pass through that one cell. If the cell tower is transmissions to a given cell must pass through that one cell. If the cell tower is destroyed in the disaster, traditional wireless service is eliminated.

destroyed in the disaster, traditional wireless service is eliminated.

3.

3. Sen

Sensor

sors in

s in pub

public

lic vehi

vehicle

cle

Pu

Puttttining g a a chchememicicalal‐‐biologicalbiological‐‐nnucuclelear ar (C(CBBNN) ) wwaarrnininng g sseensnsoor r on on eeveverryy government

government‐‐owned vehicle instantly creates a mobile fleet that is the equivalentowned vehicle instantly creates a mobile fleet that is the equivalent of an army of highly trained dogs. As these vehicles go about their daily duties of  of an army of highly trained dogs. As these vehicles go about their daily duties of  law

law enfenforceorcementment, , garbgarbage age collcollectiection, on, sewsewage age and and watwater er mainmaintenatenance, nce, etcetc.,., mu

municnicipaipalitlities ies geget t the the adaddeded d bebenenefit fit of of eaearly rly dedetectectiotion n of of CBCBN N agagentents. s. ThThee se

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throughout the area, so positive detection can be reported in real time. And since throughout the area, so positive detection can be reported in real time. And since 4G networks can

4G networks can include inherent geoinclude inherent geo‐‐location without GPS, first responders willlocation without GPS, first responders will know where the vehicle is when it detects a CBN agent.

know where the vehicle is when it detects a CBN agent.

4.

4. Cam

Cameras

eras in

in tra

traffic

ffic lig

light

ht

Som

Some e mamajojor r citcities ies havhave e dedeploployeyed d camcameraeras s on on tratraffiffic c liglights hts anand d sesend nd ththoseose images back to a central command center. This is generally done using fiber, images back to a central command center. This is generally done using fiber, which limits where the cameras can be hung, i.e., no fiber, no camera. 4G which limits where the cameras can be hung, i.e., no fiber, no camera. 4G netw

networks allow orks allow citicities es to to depdeploy loy camcameras and eras and backbackhauhaul l them wirelthem wirelesslessly. y. AndAnd instead of having to backhaul every camera, cities can backhaul every third or  instead of having to backhaul every camera, cities can backhaul every third or  fif

fifth th or or tententh th camcamerera, a, ususing ing ththe e othother er cacamemeras ras as as rorouteuter/rr/repepeaeaterters. s. ThTheseese cameras can also serve as fixed infrastructure devices to support the mobile cameras can also serve as fixed infrastructure devices to support the mobile sensor application described above

sensor application described above

..

5.

5. Fir

First res

st respon

ponder ro

der route se

ute select

lection

ion

Using fiber to backhaul cameras means that the intelligence collected flows one Using fiber to backhaul cameras means that the intelligence collected flows one way: from the camera to the command center. Using a 4G network, those images way: from the camera to the command center. Using a 4G network, those images can also be sent from the command center back out to the streets.

can also be sent from the command center back out to the streets.

Ambulances and fire trucks facing congestion can query various cameras to Ambulances and fire trucks facing congestion can query various cameras to choose an alternate route. Police, stuck in traffic on major thoroughfares, can choose an alternate route. Police, stuck in traffic on major thoroughfares, can look ahead and make a decision as to whether it would be faster to stay on the look ahead and make a decision as to whether it would be faster to stay on the main roads or exit to the side roads.

main roads or exit to the side roads.

6.

6.

Traffic control during disasters

Traffic control during disasters

4G networks can allow officials to access traffic control boxes to change inland 4G networks can allow officials to access traffic control boxes to change inland traffic lanes to green. Instead of having to send officers to every box on roads traffic lanes to green. Instead of having to send officers to every box on roads being overwhelmed by civilians who are evacuating, it can all be done remotely, being overwhelmed by civilians who are evacuating, it can all be done remotely, and dynamically.

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FUTURE

FUTURE

We do have are good reasons for 4G development and a variety of current and We do have are good reasons for 4G development and a variety of current and evolving technologies to make 4G a reality. Highlighting the primary drivers for  evolving technologies to make 4G a reality. Highlighting the primary drivers for  4G

4G wirewireless systemless systems s are are costcost, , spespeed, ed, flexflexibilibility, and ity, and univuniversaersal l acceaccess. Bothss. Both service providers and users want to reduce the cost of wireless systems and the service providers and users want to reduce the cost of wireless systems and the cost of wireless services. The less expensive the cost of the system, the more cost of wireless services. The less expensive the cost of the system, the more people who will want to own it. The high bandwidth requirements of upcoming people who will want to own it. The high bandwidth requirements of upcoming str

streameamining g vidvideo eo nenececessissitatates tes a a chachangnge e in in the the bubusinsinesess s momodedel l the the seservrviceice providers use—from the dedicated channel per user model to one of a shared providers use—from the dedicated channel per user model to one of a shared ‐‐

use, as

use, as‐‐packetspackets‐‐areare‐‐needed model. This will most likely be the model serviceneeded model. This will most likely be the model service providers use when 4G systems are commonplace (if not before).

providers use when 4G systems are commonplace (if not before). Increase

Increased speed d speed is a is a critical requiremcritical requirement for ent for 4G communicatio4G communications systems. Datans systems. Data ‐‐

rate increases of 10

rate increases of 10‐‐50X over 3G systems will place streaming audio and video50X over 3G systems will place streaming audio and video access into the hands of consumers who, with each wireless generation, demand access into the hands of consumers who, with each wireless generation, demand a much richer set

a much richer set of wirelessof wireless‐‐system features. Power control will be critical sincesystem features. Power control will be critical since some ser

some servicevices s (su(such as ch as strestreaminaming video) requg video) require much morire much more e powpower than doer than do others (such as voice). 4G’s flexibility will allow the integration of several different others (such as voice). 4G’s flexibility will allow the integration of several different LAN and WAN technologies. This will let the user apply one 4G appliance, most LAN and WAN technologies. This will let the user apply one 4G appliance, most likely a cell

likely a cell‐‐phophone/Pne/PDA DA hybrhybrid, id, for for manmany y diffdifferenerent t tasktasks—tes—telephlephony, ony, InteInternetrnet access, gaming, real

access, gaming, real‐‐time information, and personal networking control, to time information, and personal networking control, to namename a few. A 4G appliance would be as important in home

a few. A 4G appliance would be as important in home‐‐networking applications asnetworking applications as it would as a device to communicate with family, friends, and co

it would as a device to communicate with family, friends, and co ‐‐workers.workers.

Finally, a 4G wireless phone would give a user the capability of global roaming Finally, a 4G wireless phone would give a user the capability of global roaming and access—the ability to use a cell phone anywhere worldwide. At this point, and access—the ability to use a cell phone anywhere worldwide. At this point, the 4G wireless system would truly go into a

the 4G wireless system would truly go into a “one size fits all” category, having a“one size fits all” category, having a feature set that meets the needs of just about everyone.

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CONCLUSION

CONCLUSION

The mobile technology though reached only at 2.5G now, 4G offers us to provide The mobile technology though reached only at 2.5G now, 4G offers us to provide with a very efficient and reliable wireless communication system for seamless with a very efficient and reliable wireless communication system for seamless roaming over various network including internet which uses IP network. The 4G roaming over various network including internet which uses IP network. The 4G system will be implemented in the coming years which are a miracle in the field system will be implemented in the coming years which are a miracle in the field of communication engineering technology.

of communication engineering technology.

REFERENCES

REFERENCES

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1) Communications March 2002 Vol 40 No3 1) Communications March 2002 Vol 40 No3 2) Communications October 2002 Vol 38 No 10 2) Communications October 2002 Vol 38 No 10 3) Communication Systems :- Simon Haykins 3) Communication Systems :- Simon Haykins 4) 4) www.comsoc.orgwww.comsoc.org 5) 5) www.crummer.rollins.edu/journalwww.crummer.rollins.edu/journal 6) 6) www.techonline.comwww.techonline.com 7) 7) www.ieee.orgwww.ieee.org

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