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An interference cancellation (IC) scheme is studied for direct-sequence code-division multiple-access (DS-CDMA) wireless mobile channels. The multiple access interference (MAI) and the near-far problem (NFP) are the two principal shortcomings of DS-CDMA systems which restrict the both capacity and the quality enhancement. In this paper we introduce a new algorithm that is able to discover all the unknown spreading codes of the interference signals. In our proposed system, all possible MAI patterns so called replicas are generated. Then the true MAI pattern is detected by taking correlation between the received signal and the replicas. Moreover, NFP is solved by estimating the signal level of each user with assistance of pilot symbols. The receiver executes MAI cancellation with removing all interference signals. Numerical results show that the proposed scheme outperforms the conventional linear correlation receiver in both MAI and NFP without any power control strategy. The proposed method is applied to the slow fading environments such as mobile satellite and ad-hoc network communications.
Date of Conference: July 30 2007-Aug. 2 2007