Abstract:

This paper proposes a wavelet multi-user detector to reduce the influence of multiple access interference
(MAI) in CDMA systems. Based on the cooperative time-division duplex CDMA (TDD-CDMA) model combined
with a wavelet multi-resolution analysis, we establish a wavelet multi-user detector model for cooperative CDMA
systems. According to the requirement of MMSE multi-user detector, we propose a joint MMSE multi-user detector (MUD) which can reduce the cost function. By theoretical analysis, a closed-from expression of bit error rateperformance is derived. Simulation results show that the proposed wavelet multi-user detector can effectively suppressMAI and increase system capacity, especially at low SNR.

Key words: cooperation, DS-CDMA, MMSE, multi-resolution analysis, multi-user detection (MUD)