Chase decoding for space-time codes

Multiple antenna wireless systems are known to provide a higher capacity than traditional single antenna systems. Over the past few years, space-time signaling schemes that make use of this increased capacity have been studied. Because of the large capacity of multiple-input multiple-output channels, the multidimensional constellations used by these space-time techniques are large in size, making it impractical to perform optimal maximum likelihood decoding even for a moderate number of transmit antennas. In this paper, we propose a space-time version of the binary Chase decoder. The decoder generates an initial estimate of the transmitted bit sequence from successive detection and then uses this bit estimate to generate a reduced search space (or list) to perform minimum distance decoding. Three algorithms for constructing the space-time reduced search space are overviewed.