Improving the performance of spatial modulation by phase-only pre-scaling

Spatial modulation (SM) is a modulation scheme that exploits the spatial dimension of multiple-input multiple-output (MIMO) channels to encode the transmitted information. It is shown in this paper that, by properly rotating the phase of the transmitted symbols, the minimum Euclidean distance (MED) of the constellation of the received symbols can be enlarged and hence the error performance can be improved. Moreover, we propose an algorithm that incorporates an iteration process to design the phase-only pre-scaling factors, which only rotate the phases of different transmitted symbols according to the instantaneous channel realization. Simulation results demonstrate that the proposed method is capable of outperforming the conventional SM scheme and other pre-scaling SM schemes.