DS-CDMA systems using q-level m sequences: Coding map theory

GF(q) m sequences with complex spreading mapping are considered for DS-CDMA systems by referring to three different environments with increasing synchronicity levels. For all environments, performance evaluation is derived both with a deterministic approach requiring spreading sequence specification, and with a statistical derivation, based on the assumption of spreading sequence ergodicity, in order to give closed-form performance theory. The optimal mapping design criterion, through zero-mean complex code mapping, is computed for all environments and validated through several numerical tests. Performance invariance, with respect to sequence levels, has been demonstrated for low synchronous environments, where the proposed sequence gives better performance.