Distribution Decomposition and Sum-Capacity Results of Two-User Optical Intensity Multiple Access Channels

TL;DR

This paper analyzes the sum-capacity of two-user optical intensity multiple access channels under intensity constraints, deriving bounds that closely approach the true capacity at high and moderate SNR levels.

Contribution

It introduces a novel decomposition approach for maxentropic distributions to derive tighter lower bounds on sum-capacity under intensity constraints.

Findings

Bounds approach sum-capacity at high SNR

Bounds are close to sum-capacity at moderate SNR

Decomposition method improves capacity estimation accuracy

Abstract

This paper investigates the sum-capacity of two-user optical intensity multiple access channels with per-user peak- or/and average-intensity constraints. By leveraging tools from the decomposition of certain maxentropic distributions, we derive several lower bounds on the sum-capacity. In the high signal-to-noise ratio (SNR) regime, some bounds asymptotically match or approach the sum-capacity, thus closing or reducing the existing gaps to the high-SNR asymptotic sum-capacity. At moderate SNR, some bounds are also fairly close to the sum-capacity.