Efficient and accurate DS-SSMA deterministic signature sequence performance evaluation over wireless fading channels

An efficient performance evaluation technique is described for direct-sequence spread-spectrum multiple-access (DS-SSMA) systems with deterministic signature sequences over Rician flat-fading and frequency-selective fading channels (with RAKE receivers). The approach does not use any assumptions with respect to the distribution of the multiple-access interference (MAI) and is based on a formulation of the characteristic function method whose computational complexity is proportional to the spreading gain. The signature sequence type is found to strongly influence the Gaussian approximation´s accuracy which degrades severely under various conditions.