Effects of spreading code on the performance of CDMA picocellular systems with RAKE receivers

By exploiting analytical and semianalytical methodologies, performance of DS-CDMA system for picocellular applications, including multipath propagation channels and a RAKE receiver, is evaluated. The system performance is defined in terms of both the mean bit error probability and outage probability, taking the exact evaluation of spreading codes correlation into account. The spreading sequences investigated include some well known two-level sequences and multilevel sequences with complex mapping. By varying the spreading codes and propagation channel conditions, the following aspects have been considered in the numerical results: a comparison of RAKE receivers and simple correlator receivers, the trade-off between receiving taps number and performance, the degradation effects due to not ideal spreading code correlation, and a comparison between binary and multilevel sequences