Turbo Codes in Coded Cooperation using the Forced Symbol Method

Recently, cooperative diversity has been introduced where single-antenna mobiles achieve uplink transmit diversity helping each other by relaying one another´s messages. A variation of this principle is coded cooperation which partitions the codeword of each mobile and transmits portions of each codeword through independent fading channels. Coded cooperation framework has been easily extended using turbo codes. In this paper we propose a new cooperative protocol that improves the performance of turbo coded cooperation from moderate to high signal-to-noise ratios. This method uses the forced symbol method in which the basic encoder structure remains unchanged. We present computer simulation results of the proposed scheme under various inter-user channel SNRs and compare to the union bound analysis.