Co-channel interference reduction on the forward channel of a wideband CDMA cellular system

Abstract

Wideband code-division multiple access (CDMA) systems are interference-limited, and so must utilize some form of interference reduction in order to maintain an acceptable quality of service and capacity. In this paper, co-channel interference for several different CDMA architectures is evaluated. For wideband CDMA systems such as W-CDMA and cdma2000 with carrier stealing, co-channel interference is significantly reduced by the implementation of either microzoning or sectoring. The disadvantage of microzoning is that intra-cell interference is no longer ideally zero on the forward channel, as it is with sectoring and omnidirectional architectures. For wideband CDMA systems such as cdma2000 without carrier stealing, co-channel interference is reduced by both microzoning and sectoring architectures even more than in the case of W-CDMA and cdma2000 with carrier stealing. In this case, since forward channel intra-cell interference remains ideally zero, the significant reduction of co-channel interference by microzoning makes microzoning clearly superior to omnidirectional architectures.