An Improved Space-Time Decoder Under MIMO System

Optimum space-time convolution code, which provides maximum diversity and coding gain, are produced for cases with PSK modulation and various numbers of states and antennas. In this paper, we modify the conventional Viterbi algorithm used in space-time encoder under the MIMO system, and give the recursive metric equation. The modified Viterbi algorithm can be used in the receiver when the MIMO channel information is known a prior. The new approach provides an efficient method that allows a search for optimum path. Compared with the conventional decoding algorithm, the improved algorithm can be used in the every receiver respectively. It is shown that the improved algorithm is also an optimal algorithm, however, its metric convergence speed is faster than the standard Viterbi algorithm.