CDMA architecture

What is Rake Receiver ? CDMA system uses a signal fast chip rate for spreading spectrum and it has a high time resolution. For this reason, CDMA is able to recognize by decomposing each of the path to reach with the time difference.

How CDMA Works. CDMA uses a “spread-spectrum” technique whereby electromagnetic energy is spread to allow for a signal with a wider bandwidth . This approach allows several people on different cell phones to be “multiplexed” over the same channel to share a bandwidth of frequencies.

The IS-95 CDMA and CDMA radio channels use coded channels that are uniquely assigned to each user . This allows many users to operate on the same frequency. This also allows frequencies to be reused in every cell site and sectors within a cell site.

The Forward CDMA channel is the cell-to-mobile direction of communication or the downlink path. It consists of four types of channels to transmit voice and control data to the mobile. The types of forward link channels are Pilot, Sync, Paging and Traffic channels .

The CDMA channel is nominally 1.23 MHz wide . CDMA networks use a scheme called soft handoff, which minimizes signal breakup as a handset passes from one cell to another. The combination of digital and spread spectrum modes supports several times as many signals per unit of bandwidth as analog modes.