Hybrid Beamforming with Spatial Modulation in Multi-user Massive MIMO mmWave Networks

TL;DR

This paper proposes a hybrid beamforming system with spatial modulation for multi-user mmWave massive MIMO networks, achieving significant spectral efficiency gains with fewer RF chains.

Contribution

It introduces a novel system model combining spatial modulation with hybrid beamforming, demonstrating improved spectral efficiency and RF chain reduction in multi-user mmWave MIMO.

Findings

Achieves approximately 5dB gain over classical multi-user SM scheme.

Uses only 8 transmit antennas per array to reach high spectral efficiency.

Gain can be further increased by adding more antennas without extra RF chains.

Abstract

The cost of radio frequency (RF) chains is the biggest drawback of massive MIMO millimeter wave networks. By employing spatial modulation (SM), it is possible to implement lower number of RF chains than transmit antennas but still achieve high spectral efficiency. In this work, we propose a system model of the SM scheme together with hybrid beamforming at the transmitter and digital combining at the receiver. In the proposed model, spatially-modulated bits are mapped onto indices of antenna arrays. It is shown that the proposed model achieves approximately 5dB gain over classical multi-user SM scheme with only 8 transmit antennas at each antenna array. This gain can be improved further by increasing the number of transmit antennas at each array without increasing the number of RF chains.