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
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.
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.
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