Fractional symbol differential detection for DS-CDMA over Rayleigh fading channels

In this paper, a generic differential detection technique for DS-CDMA systems. Generalized fractional symbol differential detection (GFSD), is proposed and studied in Rayleigh fading channels. The symbol-level differential detection (SLD) and chip-level differential detection (CLD) are also discussed as special cases of GFSD. The decision variable of GFSD is derived as a function of processing gain and fractional factor. The average bit error rate (BER) performance is investigated in multipath time-varying channels via simulations with different parameters, such as signal to noise ratio (SNR), fading rate and number of paths. The results show that for any specific channel situation, there is an optimal fractional factor to obtain the best system performance.