Why Power Control Essential in CDMA ?

Power control is essential for the smooth operation of a cdma system. Because all users share the same rf band through the use of pn codes Each user looks like random…

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…

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…

The Core technology of 3G: CDMA

Formulated by the European standardization organization 3GPP, the core networkevolves on the basis of GSM/GPRS and can thus be compatible with the existingGSM/GPRS networks. It can be based on the…

How to Reverse Channel works in CDMA

All MS transmit on same frequency but with different PN codes to create different logical channels. Some channels marked for Access are used for signaling and control. While Walsh Codes…

MOBILE TRANSITION INTO DIFFERENT STATES

  A mobile will in one of four states after it is powered on. Initialization State In the Initialization State, the mobile tunes to the first preferred RF frequency channel…

Propagation of Electromagnetic Wave

When the radio wave propagates in the air, the electric field direction changes regularly. If the electric field direction of radio wave is vertical to the ground, the radio wave…

PN Code Generation & Masking

  PN Code Generation PN Code Generation PN codes are generated from prime polynomials using modulo 2 arithmetic. The state machines generating these codes are very simple and consist of…

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