The performance of sphere decoders for iterative Spatial Multiplexing MIMO receiver

Pohst and Schnorr-Euchner (SE) are two popular sphere decoders (SD) to perform near maximum likelihood (ML) detection in Spatial Multiplexing multiple-input-multiple-output (MIMO) system. Recent work [1] showed Pohst and SE are two variants of the well known stack sequential decoding and proposed modification to each strategy to shown significant complexity reduction but with near ML performance. This paper proposed modified Pohst and SE algorithms by taking into account the a priori information to estimate the maximum a posteriori (MAP) probability of the received symbol sequence. Simulation results show that significant performance gain can be achieved from iterative MAP approach and complexity reduction can be obtained for SE enumeration strategy with minor performance loss compared to Phost enumeration algorithm.