Power Allocation for Cooperative Bit-Interleaved Coded Modulation Systems with Decode-Remap-and-Forward Relaying

Tsang-Wei Yu, Wern-Ho Sheen, Chung-Hsuan Wang
2012 IEEE Transactions on Wireless Communications  
Cooperative bit-interleaved coded modulation (BICM) is a key technology for the next-generation wireless communication systems. This paper investigates power allocation for the cooperative BICM systems with decoderemap-and-forward (DRF) relaying. Unlike the conventional decode-and-forward relays, the DRF relays may choose different constellation mappings from that of source so as to obtain a remapping gain. In spite of its importance, the power allocation in such a system has not yet been
more » ... ed in the literature. Two new power allocation methods are proposed, aiming to minimize bit error rate at the destination. The first uses a cost function based on the minimum weighted squared-Euclidean distance (called PA-MWSED) and is optimized with the sub-gradient method. The second is based on a generalized MWSED (called PA-GMWSED) and is optimized with the Simplex method after the optimization is re-cast as a linear programming problem. Generally speaking, PA-MWSED has a better performance than PA-GMWSED but requires a higher complexity. Numerical results show that both of the proposed methods outperform the equal gain power allocation with large margins. Index Terms-Bit-interleaved coded modulation, cooperative relaying, decode-remap-and-forward, power allocation.
doi:10.1109/twc.2012.031212.110309 fatcat:tl2m5yqtmrb3jheqk6dpuhyucm