Full-Duplex MIMO Relaying: Achievable Rates under Limited Dynamic Range

TL;DR

This paper investigates the limits of full-duplex MIMO relaying systems considering hardware limitations, deriving bounds and optimization strategies to maximize achievable data rates under practical dynamic-range constraints.

Contribution

It introduces a novel analysis of achievable rates in full-duplex MIMO relays with dynamic-range limitations, including tight bounds, an optimization method, and an analytic approximation.

Findings

Derived tight bounds on achievable rates considering hardware limitations.

Proposed a nonconvex optimization approach for rate maximization.

Numerical results demonstrate the impact of system parameters on performance.

Abstract

In this paper we consider the problem of full-duplex multiple-input multiple-output (MIMO) relaying between multi-antenna source and destination nodes. The principal difficulty in implementing such a system is that, due to the limited attenuation between the relay's transmit and receive antenna arrays, the relay's outgoing signal may overwhelm its limited-dynamic-range input circuitry, making it difficult---if not impossible---to recover the desired incoming signal. While explicitly modeling transmitter/receiver dynamic-range limitations and channel estimation error, we derive tight upper and lower bounds on the end-to-end achievable rate of decode-and-forward-based full-duplex MIMO relay systems, and propose a transmission scheme based on maximization of the lower bound. The maximization requires us to (numerically) solve a nonconvex optimization problem, for which we detail a novel approach based on bisection search and gradient projection. To gain insights into system design tradeoffs, we also derive an analytic approximation to the achievable rate and numerically demonstrate its accuracy. We then study the behavior of the achievable rate as a function of signal-to-noise ratio, interference-to-noise ratio, transmitter/receiver dynamic range, number of antennas, and training length, using optimized half-duplex signaling as a baseline.