Diversity versus Multiplexing at Finite Blocklength

TL;DR

This paper analyzes the finite blocklength diversity-multiplexing tradeoff in multiple-antenna Rayleigh-fading channels, providing bounds to guide the optimal use of diversity or multiplexing in delay-sensitive, ultra-reliable communications.

Contribution

It introduces nonasymptotic bounds for the diversity-multiplexing tradeoff, enabling numerical assessment of optimal strategies based on packet size, antennas, and channel conditions.

Findings

Bounds help determine when to prioritize diversity or multiplexing.

Finite blocklength analysis offers practical insights for ultra-reliable, delay-sensitive links.

Guides design choices in MIMO systems under realistic constraints.

Abstract

A finite blocklenth analysis of the diversity-multiplexing tradeoff is presented, based on nonasymptotic bounds on the maximum channel coding rate of multiple-antenna block-memoryless Rayleigh-fading channels.The bounds in this paper allow one to numerically assess for which packet size, number of antennas, and degree of channel selectivity, diversity-exploiting schemes are close to optimal, and when instead the available spatial degrees of freedom should be used to provide spatial multiplexing. This finite blocklength view on the diversity-multiplexing tradeoff provides insights on the design of delay-sensitive ultra-reliable communication links.