W-CDMA is a 3G mobile technology that provides higher data speeds than previous technologies. It was developed by 3GPP and first launched commercially by NTT DoCoMo in Japan. W-CDMA uses CDMA to allow multiple signals over one channel, with each user assigned a unique code. It employs spread spectrum techniques like direct sequence SS and frequency hopping SS. The presentation provides information on W-CDMA history, duplexing, multiple access techniques, coding and decoding, applications, and concludes it is a growing mobile technology.

1. “W-CDMA”
PRESENTED BY-GYANENDRA PRASAD PANIGRAHI
REGD.NO-0901304190
GUIDED BY- Mr. SHAKTI NARAYANA MISHRA
DEPT.-ELECTRONICS AND COMMUNICATION ENGINEERING
GANDHI INSTITUTE OF TECHNOLOGY AND MANAGEMENT
BHUBANESWAR

2. CONTENTS
1. Introduction
2. History
3. Duplexing
4. Multiple Access Techniques
5. Spread Spectrum Techniques
6. WCDMA Coding & Decoding
7. WCDMA Technology
8. WCDMA Applications
9. Conclusion
10. References

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 today's market.
 It is specified by 3rd Generation Partnership Project
(3GPP).
 It is the key technology for UMTS.

4. HISTORY
QUALCOMM , 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.

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. 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. 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) FDMA
2) TDMA
3) CDMA

8. 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.

9. MULTIPLE ACCESS
TECHNIQUES(cont…)

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. 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. SPREAD SPECTRUM TECHNIQUE-III

13. WCDMA CODING
TURBO ENCODER

14. WCDMA DECODING
ITERATIVE MAP DECODER

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. 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. 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. REFERENCES
 T.S.Rappaport “ Wireless Communications”
 Forouzan “Data Communication And Networking”
 http://www.google.com
 http://www.google.com/wikipedia