Adaptive Antenna Subset Selection and Constellation Breakdown for Spatial Modulation

The problem of antenna subset selection (ASS) and constellation breakdown (CBD) for spatial modulation (SM) is investigated. Assuming the availability of the channel state information, an ASS scheme is introduced such that the symbol error rate of SM is minimized. A graph-based heuristic search algorithm is then proposed to significantly reduce the search complexity of ASS compared to the exhaustive search, while maintaining the performance. As it is not always optimal to use all the transmit antennas, optimal CBD in conjunction with ASS is then considered to develop an adaptive low-complexity ASS-CBD scheme.