A fast detection algorithm for concatenated overlapped code division multiplexing system

A fast decoding algorithm based on parallel detection is proposed for the serial concatenated overlapped code division multiplexing (SC-OVCDM) signals. It shows that maximum likelihood (ML) detection of SC-OVCDM inner decoder can be transformed into two parallel sub-decoders which have low computational complexity. In order to tighten the performance gap between the fast decoding algorithm and the optimum detection one, extrinsic information transfer between two sub-decoders is necessary. Simulations show that the optimum performance can be approached by the proposed algorithm. The loss in signal-to-noise ratio (SNR) compared with the ML inner code detector is within 1.2dB. Moreover, the proposed algorithm´s computational complexity cost is only one percent to the optimum algorithm which is exponential of inner OVCDM constraint length.