Non-Orthogonal Multiple Access Based on Hybrid Beamforming for mmWave Systems

TL;DR

This paper explores the integration of non-orthogonal multiple access with hybrid beamforming in mmWave systems, proposing algorithms and bounds to enhance multi-user communication efficiency.

Contribution

It introduces a sum-rate formulation and a suboptimal algorithm for HB-NOMA, along with a lower bound on achievable rates considering imperfect correlation.

Findings

The proposed algorithm improves sum-rate performance.

Imperfect correlation can lead to significant inter-cluster interference.

Numerical simulations validate the theoretical results.

Abstract

This paper aims to study the utilization of non-orthogonal multiple access (NOMA) in hybrid beamforming (HB) multi-user systems called HB-NOMA to serve a large number of mobile users (MUs). First, a sum-rate expression for the HB-NOMA problem is formulated. Second, a suboptimal algorithm is proposed to maximize the sum-rate. Then, a lower bound for the achievable rate is derived under the condition that the angle between the effective channel vectors of the MU with the highest channel gain and other MUs located inside a cluster is non-zero, which we denote by imperfect correlation. The lower bound indicates that an inefficient MU cluster, can cause severe inter-cluster interference in the network. To verify our findings, numerical simulations have been conducted.