An efficient method for computing the bit error probabilities of band-limited asynchronous DS-CDMA systems with random signature sequences

An accurate and efficient method is proposed for computing the bit error probabilities (BEP) of band-limited, asynchronous direct-sequence code-division multiple-access (DS-CDMA) systems with random signature sequences. The proposed method uses Chebyshev interpolation and moments up to the fourth order. It is inherently more accurate than an existing, efficient method called the simplified improved Gaussian approximation (SIGA), which uses moments up to the second order. Closed-form expressions for computing the BEP are presented. The superior accuracy of the proposed method is illustrated by numerical examples. The computational complexity of the proposed method is higher than, but of the same order as the SIGA.