Classical Information Capacity of the Bosonic Broadcast Channel

TL;DR

This paper analyzes the classical information capacity of the Bosonic broadcast channel, demonstrating its equivalence to a classical degraded Gaussian broadcast channel and discussing conditions for achieving capacity with coherent states.

Contribution

It establishes the capacity region of the Bosonic broadcast channel using coherent-state encoding and links it to classical Gaussian channels, providing evidence for a key conjecture.

Findings

Bosonic broadcast channel is equivalent to a classical degraded Gaussian broadcast channel

Capacity region is dual to that of the classical Gaussian multiple-access channel

Potential to achieve ultimate capacity with coherent-state encoding if a conjecture holds

Abstract

We show that when coherent-state encoding is employed in conjunction with coherent detection, the Bosonic broadcast channel is equivalent to a classical degraded Gaussian broadcast channel whose capacity region is dual to that of the classical Gaussian multiple-access channel. We further show that if a minimum output-entropy conjecture holds true, then the ultimate classical information capacity of the Bosonic broadcast channel can be achieved by a coherent-state encoding. We provide some evidence in support of the conjecture.