Performance of various multistage interference cancellation schemes for asynchronous QPSK/DS/CDMA over multipath Rayleigh fading channels

Performance of multistage interference cancellation (MIC) and three combining techniques, i.e., multipath decorrelating (MIC-DECO), optimum combining (MIC-OPTM), and Rake combining (MIC-RAKE) for asynchronous QPSK/ DS/CDMA over frequency-selective multipath Rayleigh fading channels is studied. The analytical bit error probabilities of the MIC-DECO and MIC-OPTM are derived and shown to be in a good agreement with simulation results. Both analytical and simulation results show that the MIC-DECO, MIC-OPTM, and MIC-RAKE in a multi-user environment provide a good performance close to the ideal performance in a single-user system even in the presence of channel estimation error.