Iterative SU-MIMO receivers based on SOMA demappers with improved survivor selection

We present a new class of reduced-complexity high-performance iterative receivers for single-user MIMO/OFDM systems with bit-interleaved coded modulation (BICM). The proposed inner-outer decoder structures rely on joint demappers which generate soft-output via an M-algorithm limited tree-search. A key element of the proposed designs is the way the M-algorithm chooses its survivor candidates during the tree search. In particular, at every depth in the tree the survivor list comprises the best M candidates as well as additional good candidates which are chosen to enable high-quality soft-output information for every bit. In the context of iterative inner/outer decoders, simulations show that the proposed survivor selection criteria result in superior performance/complexity trade-offs as compared to a conventional M-algorithm search.