Diversity receiver of a CDMA system in mobile multipath fading environments

A diversity receiver of a code division multiple access (CDMA) system is studied. Frame-error-rate (FER) and bit-error-rate (BER) of the forward traffic channel are obtained by using a simulation system based on TIA/EIA/IS-95. A diversity receiver structure with an adaptive search engine is developed and analyzed. The adaptive rate of the search engine is optimized to achieve high diversity gain. The relationship between receiver diversity gain and multipath channel characteristics is derived. Compared with classical diversity schemes, the proposed diversity receiver has better performance and simpler structure. The multipath channel characteristics have a major impact on the system performance. Uncaptured energy acts as interference, which can increase the FER by an order of magnitude and reduce system capacities. The system performance for the indoor and outdoor environments are obtained by utilizing the proposed diversity receiver.