A transmit antenna coding scheme for spatial modulation

Spatial modulation (SM) is performed in both spatial and signal domains. The spatial-domain modulation involves the coding process of transmit antennas (TAs). The traditional coding method uses natural binary code, which leads to relatively poor bit error rate (BER) performance in spatial correlated channels. In this paper, we propose a simple yet efficient TA coding scheme by utilizing Gray code for SM. Considering a uniform linear array (ULA), due to the fact that the correlation of two adjacent TAs far exceeds that of the other TA pairs, the BER brought out by TA indices decision can be effectively mitigated by utilizing Gray code. Simulation results show that the proposed coding scheme can effectively mitigate the bit error due to incorrect decision and thus improve the BER.