Receiver design for alternate-relaying cooperative systems with multiple antennas at the destination

This paper discusses the receiver design of a destination node supporting multiple antennas for an alternate-relaying decode-and-forward (DF) cooperative communication system. We exploit the structure of the received signal to develop an optimal data detection algorithm at the destination. It is shown that the optimal algorithm can be implemented by parallel detectors, each based on a family of Bahl, Cocke, Jelinek and Raviv (BCJR) algorithms. The proposed optimal algorithm requires to receive and store all packets before performing data detection. To avoid this, a sub-optimal algorithm is also proposed. Unlike the optimal algorithm, the sub-optimal one exploits two consecutive received packets to detect one packet. It turns out that the sub-optimal algorithm has less reduced delay, complexity, memory size and bandwidth loss with a slight increase of the bit-error-rate. The detection performance of the proposed algorithms is evaluated via Monte Carlo simulations, and the results demonstrate their effectiveness.