The Capacity Loss of Dense Constellations

TL;DR

This paper quantifies the capacity loss in complex-valued additive-noise channels when using bounded support constellations at high SNR, providing a general expression that aligns with known power loss results.

Contribution

It derives a general formula for capacity loss due to bounded constellations, extending understanding beyond specific cases like square constellations.

Findings

Capacity loss expression matches 1.53dB power loss for square constellations

Provides a general framework for capacity loss in complex channels

Applicable to various bounded support signal constellations

Abstract

We determine the loss in capacity incurred by using signal constellations with a bounded support over general complex-valued additive-noise channels for suitably high signal-to-noise ratio. Our expression for the capacity loss recovers the power loss of 1.53dB for square signal constellations.