CDMACDMA

CDMA stands for code division multiple CDMA stands for code division multiple access access

There are to major application of There are to major application of CDMA technology CDMA technology

1).3-G and onward 1).3-G and onward

2).WLL (wireless in local loop)2).WLL (wireless in local loop)

DATA SPEED IN DIFF GENRDATA SPEED IN DIFF GENR

1).data speed of 1-G 1).data speed of 1-G

2).data speed of 2-G=144kbps 2).data speed of 2-G=144kbps

3).data speed of 3-G=3.6Mbps3).data speed of 3-G=3.6Mbps

normal speed of voice =384kbpsnormal speed of voice =384kbps

One radio frequency provide 8 slots for One radio frequency provide 8 slots for the customers in GSM the customers in GSM

IT mean only 8 people can set up CALL ,if IT mean only 8 people can set up CALL ,if 100 trying to call 100 trying to call

But in CDMA all 100 people are able to talk But in CDMA all 100 people are able to talk at a particular frequency.at a particular frequency.

Condition is that all100 information are Condition is that all100 information are separated by 100 diff codes is called separated by 100 diff codes is called

WALL CODE WALL CODE

CDMA: Code Division Multiple CDMA is a method in which users occupy the same time and frequency allocations, and are channelized by unique assigned codes. The signals are separated at the receiver by using a correlator that Access

accepts only signal energy from the desired channel. Undesired signals contribute only to the noise.

A CDMA system uses effective power control process.

CDMACDMA

Advantages:-

The main advantages of this technology are:

1. Fast Network deployment.

2. Reduced service interruptions.

3. Low Maintenance & operational cost.

4. Better system coverage flexibility

5. Higher capacity

6. Easy transition to mobile services.

CDMACDMA

All information of users are on the same All information of users are on the same frequency each information of the user is frequency each information of the user is separated by a code separated by a code

Digital code separates the information to Digital code separates the information to stop the interference stop the interference

OR OR

Transmission and receive of signal separated Transmission and receive of signal separated by a code using the same frequency by a code using the same frequency symaltaneously by a number of users is symaltaneously by a number of users is known as code division multiple access known as code division multiple access (CDMA) (CDMA)

SYMBOLIC STRU OF CDMASYMBOLIC STRU OF CDMA __________________________________________________________ >0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0 >0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0 >0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0 >0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0 >0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0 >0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0 >0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0>0 ________________________________________________________

HERE “>” STANDS FOR AN INFORMATION HERE “>” STANDS FOR AN INFORMATION AND “0” STANDS FO SEPARATOR OR WALSH CODEAND “0” STANDS FO SEPARATOR OR WALSH CODE

______________________________________

““HANDS OFF” COM. SYS. HANDS OFF” COM. SYS.

When a cell phone come into more When a cell phone come into more than one BTS area then the BTS than one BTS area then the BTS near to the is connected easily this near to the is connected easily this process is known as HANDS OFFprocess is known as HANDS OFF

TYPES OF HANDS OFF TYPES OF HANDS OFF

1).SOFT HANDS OFF =|>”MAKE BEFORE 1).SOFT HANDS OFF =|>”MAKE BEFORE BREAK “BREAK “

2).HARD HANDS OFF =>”MAKE 2).HARD HANDS OFF =>”MAKE

AFTER BREAK AFTER BREAK

SOFT HANDS OFF SOFT HANDS OFF

CDMA provides soft hands off features CDMA provides soft hands off features

for mobile .for mobile .

When cell phone crossing one CELL to When cell phone crossing one CELL to

other by combining the signals from both other by combining the signals from both the cells . This includes the performance the cells . This includes the performance of the network at the boundary of the of the network at the boundary of the cell the call being dropped. cell the call being dropped.

By soft hands off in CDMA will combine By soft hands off in CDMA will combine together of two BTS and create a together of two BTS and create a common higher level common higher level

HARD HANDS OFF HARD HANDS OFF

Hard hands off is also known as “MAKE Hard hands off is also known as “MAKE

AFTER BREAK “AFTER BREAK “

BTS

IWF

BSC

MSC

I

PSTN

IP Backbone

Enterprise Network

• MULTIPLE ACCESS

• SPREADING SPECTRUM

• CODES IN CDMA

• CDMA CHANNEL STRUCTURE

• POWER CONTROL

• DIVERSITY

• HAND OFFS

THANKYOUTHANKYOU