Capacity Limits and Multiplexing Gains of MIMO Channels with Transceiver Impairments

TL;DR

This paper investigates how physical transceiver impairments affect MIMO channel capacity, revealing a finite capacity limit at high SNR and demonstrating that MIMO still offers significant relative capacity gains despite impairments.

Contribution

It analytically shows that transceiver impairments cause a finite capacity limit in MIMO channels and proves that MIMO's relative capacity benefits remain substantial.

Findings

Finite upper capacity limit due to impairments

High-SNR slope collapses to zero with impairments

MIMO still provides at least as large relative capacity gains

Abstract

The capacity of ideal MIMO channels has a high-SNR slope that equals the minimum of the number of transmit and receive antennas. This letter analyzes if this result holds when there are distortions from physical transceiver impairments. We prove analytically that such physical MIMO channels have a finite upper capacity limit, for any channel distribution and SNR. The high-SNR slope thus collapses to zero. This appears discouraging, but we prove the encouraging result that the relative capacity gain of employing MIMO is at least as large as with ideal transceivers.