Cluster Index Modulation for Reconfigurable Intelligent Surface-Assisted mmWave Massive MIMO

In this paper, we propose a transmission mechanism for reconfigurable intelligent surface (RIS)-assisted millimeter wave (mmWave) system based on cluster index modulation (CIM), named best-gain optimized selection CIM (BGCS-CIM). The proposed BGCS-CIM scheme considers effective power gain and spatial diversity obtained by the additional paths within indexed to construct an efficient codebook. We also integrate into practical model create virtual path between transmitter receiver where direct link has been blocked. Thanks designed whitening filter, closed-form expression upper bound average bit error rate (ABER) is derived used validate simulation results. It shown that outperforms existing benchmarks thanks its higher gain, of clusters, lower inter-cluster interference.