Generalized Spatial Modulation with Transmit Antenna Grouping for Massive MIMO

In this paper, we propose an innovative generalized spatial modulation (GSM) scheme namely grouping GSM (gGSM) to improve the system performance against the high channel correlation in massive MIMO systems. In the proposed scheme, the transmit antennas are divided into several equal-sized groups, and each group conducts spatial modulation (SM) independently. Two grouping methods, i.e., block grouping and interleaved grouping are proposed. In block grouping, the adjacent antennas are gathered in the same group. While in interleaved grouping, the average distance between the antennas in the same group is maximized in order to minimize the impact of channel correlation. In consideration of the practical massive MIMO systems, we conduct the proposed scheme both in a linear antenna array and a 2-dimensional antenna array. To evaluate the performance, we derive a closed-form average bit error probability (ABEP) upper bound for the proposed scheme. According to the ABEP upper bound, we derive the coding gain and diversity order of the proposed scheme to gain insight into the system performance. Numerical results show the performance gain achieved by the proposed scheme compared with the conventional GSM in terms of bit error rate.