RAYLEIGH FADING EFFECT REDUCTION WITH WIDE-BAND DS CDMA SIGNALS

Mobile radio fading analyses typically assume a single frequency carri er transmitted through the propagation medium. The results are then us ed for the case of narrowband transmission. New phenomena occur with w ideband transmission. This paper presents an analysis of the mitigatio n of the Rayleigh fading effect for wideband direct sequence code divi sion multiple access (DS/CDMA) signaling. There are measurements that show this phenomenon. The reduction of the Rayleigh fading effect is a n advantage of CDMA over narrowband transmission systems and it eases the burden of CDMA power control. A general expression for the coeffic ient of variation of the received wideband signal power is derived. It is shown how the coefficient of variation of the received power decre ases as the bandwidth spreading increases. This paper also analyzes th e time correlation needed for other analyses (e.g., CDMA power control ).