Optimal Achievable Rates for Interference Networks with Random Codes

TL;DR

This paper characterizes the optimal rate region for interference networks using random codes and superposition coding, showing a simple decoding rule achieves this region and that the Han-Kobayashi bound is optimal under these conditions.

Contribution

It demonstrates that a straightforward simultaneous nonunique decoding rule attains the optimal rate region for interference networks with random coding, without the need for more complex decoding strategies.

Findings

Simple decoding rule achieves optimal rate region.

Han-Kobayashi bound is optimal with random codes.

Optimal rates are characterized for interference networks.

Abstract

The optimal rate region for interference networks is characterized when encoding is restricted to random code ensembles with superposition coding and time sharing. A simple simultaneous nonunique decoding rule, under which each receiver decodes for the intended message as well as the interfering messages, is shown to achieve this optimal rate region regardless of the relative strengths of signal, interference, and noise. This result implies that the Han-Kobayashi bound, the best known inner bound on the capacity region of the two-user-pair interference channel, cannot be improved merely by using the optimal maximum likelihood decoder.