WCDMA Source Coding

AMR (Adaptive Multi-Rate) Speech A integrated speech codec with 8 source rates The AMR bit rates can be controlled by the RAN depending on the system load and quality of…

WCDMA Block Coding – CRC

Block coding is used to detect if there are any uncorrected errors left after error correction. The cyclic redundancy check (CRC) is a common method of block coding. Adding the…

What is RAKE RECEIVER and its Purpose in CDMA

Rake Receiver Instead of trying to overpower or correct multipath problems, CDMA takes advantage of the multipath to improve reception quality in fading conditions. CDMA does this by using multiple…

Functionally of EPC in LTE

EPC ( Evolved Universal Terrestrial Radio Access Network) Functionally the EPC is equivalent to the packet switched domain of the existing 3GPP networks. EPC consist of:–MME (Mobility Management Entity)–SAE GW…

Second-Generation Broadband Systems

Second-generation broadband wireless systems were able to overcome the LOS issue and to provide more capacity. This was done through the use of a cellular architecture and  implementation of advanced-signal…

Soft/Softer Handoff in CDMA

Multi-path combination in the BSC during soft handoffMulti-path combination in the BTS during softer handoffs       Soft handoff means that during the handoff of a mobile station at the coverage…

Forward Power Control in CDMA

Message Transmission Mode MS measures the frame quality and informs the base station to the result i.e. whether it is in the threshold or periodical  mode. Base station determines whether …

Scrambling (M) sequence in CDMA

  Two points are important here:  Maximum number of shift register (N)  Mask The period of out put sequence is 2N-1 bits Only sequence offset is change when the mask…

Spreading Technology in WCDMA

Spreading consists of 2 steps: Channelization operation, which transforms data symbols into chips Scrambling operation is applied to the spreading signal Spreading means increasing the bandwidth of the signal beyond…

How Transport Channel Work in LTE?

A transport channel defines how and with what characteristics the information is transmitted. Inherited from the WCDMA, data on the transport channel is organized into “Transport Blocks”, TBs. A Transport…

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