Abstract: A new low complexity iterative detection algorithm is proposed for the space-time bit interleaving coded modulation system. By utilizing the characteristics of the interleaving and the central limited theorem, the superstition of the transmitted signals at the receiver is first assumed as a Gaussian random variable. Therefore, the matrix inverse calculation can be avoided, which enables the proposed method to be used in a system with more transmitter antennas than receiver antennas. Under the previous assumption, P most significant symbol combinations are identified via the sequential principle to calculate the log likelihood ratio of each bit, which will be used by the iterative decoding. Compared with the available sequential algorithm, the proposed method reduces the complexity without sacrificing any performance.

Key words: Bell Lab. layered space-time architecture, space-time interleaving coded modulation, soft-input soft-output, Gaussian approximation