Application of saddlepoint integration on forward-link analysis of asynchronous cellular DS-CDMA over fading channels

The bit-error rate (BER) analysis of an asynchronous cellular direct-sequence code-division multiple-access (DS-CDMA) system over Rician fading channels often results in a complicated multi-integral expression even though Gaussian approximation is applied. As a result, saddlepoint integration (SPI) is introduced to evaluate the BER performance efficiently and accurately. The computational effort of this method grows only linearly with the number of interfering cells in the system, regardless of the number of active mobiles in each cell. The probability density function (pdf) for multiple Rayleigh interferers is compared to that obtained through the combined pdf (c-pdf) approach. Finally, the analysis for the Rician fading channel is evaluated using the SPI technique. The results obtained are accurate compared to the simulation data.