Abstract —Spectral efficiency and transmission reliability are among the main design considerations of modern wireless communication systems. In order to solve the problems of high decoding complexity, low spectrum utilization in bidirectional multi-relay cooperative communication system, combining the advantages of Random Cyclic Delay Diversity (RCDD) technology and Adaptive Forwarding Factor (AFF), a distributed space-time-frequency cooperative transmission scheme is proposed in this paper, which has the advantages of low decoding complexity and high spectrum utilization. Compared with the scheme only using Cyclic Delay Diversity (CDD) technology, this scheme can further excavate the diversity gain of the system and improve the performance of Bit Error Ratio (BER) and channel capacity.
 
Index Terms—Distributed, adaptive forwarding factor, randomized cyclic delay diversity