Abstract: For the purpose of cutting down the influence of multi-access interference on the performance of a CDMA(Code-Division Multiple-Access) system, we combine a turbo decoder with a multi-user detector organically and present the iterative multi-user detection technology. The turbo decoder is taken as the input soft-in information generated by multi-user detection, and produces a posteriori probabilities, which is used as a priori probabilities by multi-user detection. After a certain number(usually more than 3)of iterations the decoder makes a hard decision and outputs the result. The simulation result presented shows that iterative Multi-user Detection Technology enables the system to improve in performance greatly, which is near (less than 1dB) single user performance.

Key words: iterative decoding, Turbo codes, CDMA, multi-user detection