User cooperation diversity for multi-user CCMA

In this paper, we introduce a user cooperation diversity scheme for uplink Collaborative Coded Multiple Access (CCMA) system. In this scheme, the cooperating users transmit their own codewords and that of their partners' employing collaborative coding. The base-station receives two copies of the composite codeword signals via two different channels. Joint detection and decoding is employed at the receiver to recover the individual users' codewords and their data based on the minimum distance criteria of collaborative coding. The bit error performance of the proposed technique is analysed in flat Rayleigh fading channels with AWGN, and shown to provide significant gain compared to CCMA with no cooperation and near to that of CCMA using dual receive diversity.