The Effects Of Fading And Interference On The Performance Of Direct-Sequence Spread Spectrum Systems

Abstract

The effects of fading and interference on the performance of a Direct-Sequence Spread Spectrum Multiple Access system using Uiffcrcntial Phase Shift Keying modulation are investigated. The average bit error rate as a function of the signal-to-noise ratio is used as a performance measure for thc system. ‘The system error probability is evaluated using Gold codes of length L = 127 and operating under Rayleigh fading conditions. The system error rate is also investigated for the case of two intcrfcring signals and compared with the corresponding probabilities for no interference and/or no fading. ‘l‘he results show that the best performance occurs in thc absence of intcrfercnce and fading, while the worst performmce occurs when fading and interference are both present.