“W-CDMA”PRESENTED BY-GYANENDRA PRASAD PANIGRAHI

REGD.NO-0901304190GUIDED BY- Mr. SHAKTI NARAYANA MISHRA

DEPT.-ELECTRONICS AND COMMUNICATION ENGINEERING

GANDHI INSTITUTE OF TECHNOLOGY AND MANAGEMENT

BHUBANESWAR

CONTENTS1. Introduction2. History3. Duplexing4. Multiple Access Techniques5. Spread Spectrum Techniques6. WCDMA Coding & Decoding7. WCDMA Technology8. WCDMA Applications9. Conclusion10. References

INTRODUCTIONWCDMA stands for Wide Band Code

Division Multiple Access.

W-CDMA is a Third-Generation(3G) mobile wireless technology that promises much higher data speeds to mobile and portable wireless devices than commonly offered in today's market.

It is specified by 3rd Generation Partnership Project (3GPP).

It is the key technology for UMTS.

HISTORYQUALCOMM , the first company to

succeed in developing a practical and cost effective CDMA implementation for consumer cell phones.

The world's first commercial W-CDMA service was launched by NTT DoCoMo in Japan.

DUPLEXING It means to allow the Subscriber to send

simultaneously information to the base station while receiving information from the base station.

It is of two types. (a) FDD (b) TDD In FDD ,

(1) Forward Band :- Traffic from base station to mobile (2) Reverse Band :- Traffic from mobile to base station

DUPLEXING(cont…) In FDD Duplexer is used.The frequency separation between each

forward & reverse channel is constant through out the system.

In TDD , Time is used to provide both a forward & reverse link.

Each duplex channel has forward & reverse time slots.

Duplexer is not required. It is effective when all the users are stationary.

MULTIPLE ACCESS TECHNIQUESThese are used to allow many mobile users to

share a finite amount of radio spectrum simultaneously.

The sharing of spectrum is required to achieve high capacity by simultaneously allocating the available bandwidth (or) available amount of channels to multiple users.

Multiple access techniques are of three types.1)FDMA2)TDMA3)CDMA

MULTIPLE ACCESS TECHNIQUES(cont…)In FDMA, It assigns individual channels to

individual users. Each user is allocated a unique frequency band.

In TDMA, It divides radio spectrum into time slots and in each slot only one user is allowed to either transmit or receive.

In CDMA, It allows numerous signals to occupy a single Transmission channel, optimizing the use of available bandwidth. It employs analog-to-digital conversion & Spread Spectrum Technology. Each user has a unique code word. Unlike TDMA or FDMA CDMA has a soft capacity limit.

MULTIPLE ACCESS TECHNIQUES(cont…)

SPREAD SPECTRUM TECHNIQUE-IA kind of modulation system in which the

modulated signal bandwidth is much greater than the message signal bandwidth.

The spectral spreading is performed by a code that is independent of the message signal.

Codes are fully orthogonal. It is of two types .1)DS-SS2)FH-SS

SPREAD SPECTRUM TECHNIQUE-IIIn DS-SS, it spreads the base band data by

directly multiplying the base band data pulses with a pseudo-noise (PN) sequence.

In FH-SS, frequency hopping means periodic change of transmission frequency. A frequency hopping signal may be regarded as a sequence of modulated data with time varying pseudo random carrier frequencies.

The DS-Multiple Access is known as CDMA.

SPREAD SPECTRUM TECHNIQUE-III

WCDMA CODING

TURBO ENCODER

WCDMA DECODING

ITERATIVE MAP DECODER

WCDMA TECHNOLOGY Asynchronous network operation Cell search Soft handover Compressed mode OVSF codes Data rate indication Speech codec High-speed packet data Broadcast and multicast services

WCDMA APPLICATIONSFor the consumer

Video streaming, TV broadcastVideo calls, video clips – news, music, sportsEnhanced gaming, chat, location services…

For businessHigh speed teleworking Sales force automationVideo conferencingReal time financial information

CONCLUSION

WCDMA has many advantages like much higher B.W (5 MHz),high chip rate(3.84Mcps),high data rate(up to 2 Mbps),enhanced security and so on…

Thus it is the growing technology for mobile generations.

REFERENCEST.S.Rappaport “ Wireless Communications” Forouzan “Data Communication And

Networking”http://www.google.com http://www.google.com/wikipedia

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