Performance of DS-CDMA Over Measured Indoor Radio Channels Using Random Orthogonal Codes

Direct sequence spread spectrum, with its inherent resistance to multipath interference, has become a commercial reality for indoor wireless communications and has been proposed for personal communication networks. To allow multiple users within the limited bandwidths allocated by the FCC, codedivision multiple-access (CDMA) is needed. This paper analyzes the performance of CDMA systems using random orthogonal codes over fading multipath indoor radio channels using channel measurements from five different buildings. The effect of RAKE receiver structure is studied, as is the effect of average power control. The average probability of error as a function of signalto-noise ratio is used as the performance criteria. Results are compared with models for Rayleigh fading channels. width efficiency of M-ary orthogonal codes over nonfading channels is discussed in [9], and over fading channels in [lo]. This paper analyzes such a system using measured multipath fading channel data. The particular examples use the measured multipath characteristics from five manufacturing areas [ 111 and a bandwidth permitted by the FCC [3]. A RAKE receiver structure is investigated and compared with theoretical results for Rayleigh fading channels.