Approaching the Gaussian channel capacity with APSK constellations

TL;DR

This paper demonstrates that APSK constellations with equiprobable signaling can asymptotically achieve the Gaussian channel capacity by increasing the number of constellation points, focusing on constellation shaping techniques.

Contribution

It introduces a construction of APSK constellations that attain Gaussian capacity asymptotically with equiprobable signaling, advancing constellation shaping methods.

Findings

APSK constellations can approach Gaussian capacity as points increase.

Equiprobable APSK constellations are effective for capacity achievement.

Theoretical proof of asymptotic optimality of the proposed APSK design.

Abstract

We consider the Gaussian channel with power constraint P. A gap exists between the channel capacity and the highest achievable rate of equiprobable uniformly spaced signal. Several approaches enable to overcome this limitation such as constellations with non-uniform probability or constellation shaping. In this letter, we focus on constellation shaping. We give a construction of amplitude and phase-shift keying (APSK) constellations with equiprobable signaling that achieve the Gaussian capacity as the number of constellation points goes to infinity.