A New Modified Gaussian Approximation Detector for Space-Time Bit-Interleaved Coded Modulation Schemes

To reduce the receiver complexity of space-time bit-interleaved coded modulation (ST-BICM) schemes, this paper describes a turbo-type iterative receiver structure consisting of a modified Gaussian approximation detector (MGA) and an a posteriori probability (APP) decoder. Utilizing the characteristics of interleaving and the central limited theorem, MGA first assumes the superposition of the transmitted signals as a Gaussian random variable. Then, P most significant signal combinations are identified to calculate the log-likelihood ratio of each bit. Without any pre-process on the received signals, the proposed method is free of matrix inverse operation and can be applied to systems with more transmitter antennas than receiver antennas. Furthermore, the performance of MGA approaches that of optimal detection under various channel environment