An approach to data detection and fading amplitude estimation in asynchronous CDMA-systems on Rayleigh-flat-fading channels

For an asynchronous direct-sequence CDMA system two different multistage multiuser detection schemes are discussed. Taking into consideration transmission over a frequency-nonselective slowly fading channel one has to cope with the problem of joint data detection and channel estimation. Simulation results assuming a perfect knowledge of the channel coefficients are discussed to compare the two multistage detection schemes. The numerical results give reason to the fact that both iterative detection schemes are near-far resistant and that they perform at a low bit error rate having a reasonable computational complexity. The paper concludes giving some different approaches for the joint detection and estimation problem.