4g Wireless Communications

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    4G WIRELESS

    COMMUNICATIONS

    By

    K Arathi

    096P1A0406

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    Contents

    Introduction

    Features of 4G

    Technology used in 4G

    3G Vs 4G

    Challenges in 4G

    Conclusion

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    Introduction

    Abbreviation of fourth generation wirelesstechnology

    It will provide a comprehensive IP solution wherevoice , data and multimedia can be given to user onan anytime , anywhere basis.

    It includes several types of broadband wirelesscommunication system access including cellular

    telephone system.

    It will provide seamless mobility and internet accessat a rate of 100 Mbps.

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    Features of 4G Networks

    4G networks are all-IP(Internet Protocol) basedheterogeneous networks

    This will allow users to:

    Select any system atany time and any where

    Use Multiple systems atthe same time (e.g.GPS and WLANs and

    CDMA)

    A wide range ofapplications using onlyone 4G integratedterminal

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    Features of 4G (cont)

    Support for multimedia services like teleconferencing andwireless internet.

    Wider bandwidths and higher bitrates.

    Entirely packet-switched network.

    Global mobility and service portability.

    Support for previous wireless technologies.

    High internet speed.

    tight network security.

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    6

    RNCBase

    Station

    Access

    Gwy

    BaseStation

    RNCBaseStation

    Access

    Gwy

    All IP Core

    Network

    4G Access Network

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    Technology used in 4G

    OFDM

    UWB

    Smart antennas

    IPv6

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    OFDM

    IT transmits large amounts of digital data over a radio wave.

    OFDM works by splitting the radio signal into multiplesmaller sub-signals that are then transmitted simultaneouslyat different frequencies to the receiver .

    By inserting a cyclic prefix between adjacent OFDM signalinter signal interference is virtually eliminated if the max.channel delay spread is less than the time interval of cyclic

    prefix.

    In OFDM the subcarrier pulse used for transmission isrectangular.

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    UWB

    An advanced technology that can be used in 4G technology.

    It is typically detected as noise.

    It can use any part of the frequency spectrum, which means

    that it can use frequencies that are currently in use by otherradio frequency devices .

    It uses a frequency of 3.1 to 10.6 Hz.

    It uses less power , since it transmits pulse instead ofcontinuous signal.

    Special antennas are needed to tune and aim the signal.

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    Smart Antennas

    smart antenna can be employed to find tune ,and turn up signalinformation.

    smart antenna can send signal back in the same direction that they comefrom.

    There are two types of smart antennas-

    switched beam antenna:- It has fixed beams of transmission, and switchfrom predefined beam to another when the user with the phone movesthroughout the sector.

    Adaptive array antenna :- It represents the most advanced smart antennaapproach to data using a variety of new signal It represent the mostadvanced smart antenna approach to date using a variety of new signalprocessing algorithms to locate and track the user, minimize interference,and maximize intended signal reception.

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    IPv6

    IPv6 means Internet Protocol Version 6 .

    The Internet Protocol (IP) is the method or protocol which data is

    sent from one computer to another on the internet.

    Each computer (known as a host) on the Internet has at least one IP

    that uniquely identifies it from all other computers on the Internet.

    It includes128 bits, which is 4 times more than 32bits IP address in

    IPv4.

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    3G Vs 4G

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    Challenges in 4G

    Multi-access interface, timing and recovery.

    Higher frequency reuse leads to smaller cells that may causeintra-cell interference or higher noise figures due to reduced

    power levels.

    The Digital to analog conversions at high data rates,multiuser detection and estimation (at base stations), smartantennas and complex error control techniques as welldynamic routing will need sophisticated signal processing.

    Issues in the interface with the ad hoc networks should besorted out.

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    Challenges in 4G (cont)

    Voice over multi-hop networks is likely to be an interestingproblem because of the strict delay requirements of voice.

    Security will be an important issue.

    A new IP protocol might be needed because of the variableQoS services and the network should do " better than best "effort.

    Networking protocols that adapt dynamically to the changing

    channel conditions.

    Seamless roaming and seamless transfer of services.

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    Conclusion

    The work on 4G systems has begun in the industry as well theacademia.

    In the USA, Motorola, Lucent, AT&T, Nortel and other majorcompanies are also working on 4G systems.

    Multimedia traffic will be dominant in the future. It isestimated that voice would contribute to only 20-30 % oftotal traffic in the future.

    A modified IP will be the universal network layer protocol inthe future.

    The entire network would be digital and packet switched.

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    References

    Wikipedia

    IEEE digital library

    FAQs on 4G

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    THANK

    YOU