Coded Cooperation In Turbo-Code Using Log- Map Decoder

The user cooperation technique called, coded cooperation, where cooperation is achieved through channel coding method using turbo decoder. Each code word is partitioned into two subsets that are transmitted from the user’s and partner’s antennas respectively. Coded cooperation achieves impressive gains compared to a non-cooperative system while maintaining the same information rate, transmit power and bandwidth. In this paper we have analyzed the performance of the Log-Map (log-maximum a posteriori probability) for the Turbo Decoder. The various decoding algorithms are available for decoding of turbo codes. The performance of log-map over the AWGN channel is obtained. The BER and SNR performances of Log-Map are compared. It has been verified by the simulation results that the proposed adaption to the fixed scaling factor method gives enhanced results of the performance of Log-Map. The performance of SOVA (Soft Output Viterbi Algorithm) for turbo decoder to be analyzed. The performance of SOVA will be compared to the Log-Map over the AWGN channel. Using coded cooperation method gives superior performance than existing method like amplify-and-forward, decode-and-forward. Simulations of this work will be in MATLAB