Spatially Modulated Sparse Code Multiple Access in Uplink Mine Communications

The underground coal mining communication sys-tem puts forward higher communication requirements owing to the harsh environment and multiple-user communications in the practical scenario. For improving communication quality such as bit error rate (BER) in the coal mining system, we use the spatial modulation (SM) and sparse code multiple access (SCMA) jointly in the uplink transmission. In this multiple-input multiple-output (MIMO) system, conformal microstrip patch arrays are adopted. By exploiting the message passing algorithm to detect the sparse symbols, the base station is capable of serving multiple users simultaneously and hence solves the system overload problem. Taking the blockages and tunnel geometry into account, we investigate the BER pertaining to distinct distances when different fading distributions are involved. Finally, numerical results are given to verify the efficiency of this scheme.