Sorted Phase Rotation Spatial Modulation in MISO Channel

In this paper, a sorted phase rotation assisted spatial modulation (SM) is developed to optimize the spatial constellation of the received signals in SM multiple input single output (MISO) system. The proposed scheme improves the conventional phase alignment based SM by sorting the Euclidean norm of the channel, and utilizing the sorting results to adjust the phase of each transmit antenna to further optimize the minimum Euclidean distance (MED) of the received constellation. By adopting a phase rotation criterion that is based on the sorted Euclidean distance at the transmitter, the propsed scheme, termed as SM-SPR is presented in this paper. An upper bound of the bit error rate (BER) for the proposed SM-SPR with MISO configuration is also derived in this paper. Simulation results demonstrate that the proposed SM-SPR scheme achieves significant performance gain than conventional SM system. Furthermore, it outperforms the conventional phase alignment assisted SM with improved MED of the constellation.