Fundamental Rate-Reliability-Complexity Limits in Outage Limited MIMO Communications

TL;DR

This paper establishes fundamental theoretical limits on the tradeoffs between rate, reliability, and computational complexity in outage-limited MIMO communications, providing explicit designs and policies that achieve these optimal bounds.

Contribution

It derives the fundamental limits of rate, reliability, and complexity in outage-limited MIMO systems and identifies encoder-decoder schemes that attain these bounds.

Findings

Optimal rate-reliability-complexity tradeoffs characterized

Explicit encoder-decoder designs meeting the limits identified

Quantitative measures of efficiency per complexity and power provided

Abstract

The work establishes fundamental limits with respect to rate, reliability and computational complexity, for a general setting of outage-limited MIMO communications. In the high-SNR regime, the limits are optimized over all encoders, all decoders, and all complexity regulating policies. The work then proceeds to explicitly identify encoder-decoder designs and policies, that meet this optimal tradeoff. In practice, the limits aim to meaningfully quantify different pertinent measures, such as the optimal rate-reliability capabilities per unit complexity and power, the optimal diversity gains per complexity costs, or the optimal number of numerical operations (i.e., flops) per bit. Finally the tradeoff's simple nature, renders it useful for insightful comparison of the rate-reliability-complexity capabilities for different encoders-decoders.