Novel decoding algorithms for decode-and-forward cooperative beamforming systems

In this study, two novel decoding algorithms for cooperative beamforming (CBF) systems are proposed. In decode-and-forward-based CBF, multiple relay nodes decode the packets transmitted from the source node and forward them to the destination node. However, decoding errors at the relay nodes cause erroneous retransmission of packets, which degrades the signal decoding performance at the destination node. To solve this problem, the optimal decoding strategy is derived; this strategy takes the potential errors in forwarded signals into account in the computation of the likelihood ratio of coded bits. Furthermore, to reduce the required computational complexity, a suboptimal decoding algorithm, which assumes that only one of the multiple relayed signals potentially contains errors in each time slot, is also proposed. In simulation results, it is observed that the proposed decoding algorithms for CBF provide performance improvements in terms of the achievable packet error rates with respect to the conventional schemes.