Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

W cdma

2,069 views

Published on

Published in: Education
  • Be the first to comment

W cdma

  1. 1. “W-CDMA” PRESENTED BY-GYANENDRA PRASAD PANIGRAHI REGD.NO-0901304190 GUIDED BY- Mr. SHAKTI NARAYANA MISHRA DEPT.-ELECTRONICS AND COMMUNICATION ENGINEERINGGANDHI INSTITUTE OF TECHNOLOGY AND MANAGEMENT BHUBANESWAR
  2. 2. CONTENTS1. Introduction2. History3. Duplexing4. Multiple Access Techniques5. Spread Spectrum Techniques6. WCDMA Coding & Decoding7. WCDMA Technology8. WCDMA Applications9. Conclusion10. References
  3. 3. INTRODUCTION WCDMA 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 todays market. It is specified by 3rd Generation Partnership Project (3GPP). It is the key technology for UMTS.
  4. 4. HISTORYQUALCOMM , the first company to succeed in developing a practical and cost effective CDMA implementation for consumer cell phones.The worlds first commercial W-CDMA service was launched by NTT DoCoMo in Japan.
  5. 5. 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
  6. 6. 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.
  7. 7. MULTIPLE ACCESS TECHNIQUES These 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
  8. 8. MULTIPLE ACCESSTECHNIQUES(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.
  9. 9. MULTIPLE ACCESSTECHNIQUES(cont…)
  10. 10. SPREAD SPECTRUM TECHNIQUE-I  A 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-SS 2) FH-SS
  11. 11. SPREAD SPECTRUM TECHNIQUE-II In 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.
  12. 12. SPREAD SPECTRUM TECHNIQUE-III
  13. 13. WCDMA CODING TURBO ENCODER
  14. 14. WCDMA DECODING ITERATIVE MAP DECODER
  15. 15. 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
  16. 16. WCDMA APPLICATIONSFor the consumer  Video streaming, TV broadcast  Video calls, video clips – news, music, sports  Enhanced gaming, chat, location services…For business  High speed teleworking  Sales force automation  Video conferencing  Real time financial information
  17. 17. 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.
  18. 18. REFERENCES T.S.Rappaport “ Wireless Communications” Forouzan “Data Communication And Networking” http://www.google.com http://www.google.com/wikipedia

×