Iterative approaches of cooperative transmission based on superposition modulation

The paper considers a new cooperative transmission strategy based on superposition and iterative multiuser detection techniques. The new scheme is an improved decode and forward scheme in which the two users take turns in being the relay for each other and the signal forwarded by each user is the superimposed data of both users. Here, interleavers are introduced in the superimposing process as an efficient user separation tool, providing a large improvement in system performance and also facilitating the decoding process at the destination. Two types of iterative receivers are investigated in the paper. The performance of the scheme is evaluated by simulation. It is shown that the two iterative approaches achieve similar performance. Also, the proposed scheme is about 2-3.5 dB better than an existing superposition based decode and forward cooperative scheme.