PAR-Aware Large-Scale Multi-User MIMO-OFDM Downlink

TL;DR

This paper proposes a novel joint MU precoding and OFDM modulation scheme with a convex optimization approach to significantly reduce PAR in large-scale MU-MIMO-OFDM systems, enabling cost-effective RF components.

Contribution

It introduces a new joint precoding and modulation method with an efficient algorithm for PAR reduction in large-scale MU-MIMO-OFDM systems.

Findings

Tremendous PAR reduction demonstrated

Enables use of low-cost RF components

Improves power efficiency and system cost-effectiveness

Abstract

We investigate an orthogonal frequency-division multiplexing (OFDM)-based downlink transmission scheme for large-scale multi-user (MU) multiple-input multiple-output (MIMO) wireless systems. The use of OFDM causes a high peak-to-average (power) ratio (PAR), which necessitates expensive and power-inefficient radio-frequency (RF) components at the base station. In this paper, we present a novel downlink transmission scheme, which exploits the massive degrees-of-freedom available in large-scale MU-MIMO-OFDM systems to achieve low PAR. Specifically, we propose to jointly perform MU precoding, OFDM modulation, and PAR reduction by solving a convex optimization problem. We develop a corresponding fast iterative truncation algorithm (FITRA) and show numerical results to demonstrate tremendous PAR-reduction capabilities. The significantly reduced linearity requirements eventually enable the use of low-cost RF components for the large-scale MU-MIMO-OFDM downlink.