# A New Achievable Rate Region for Multiple-Access Channel with States

## TL;DR

This paper introduces a novel coding scheme using quasi-group codes for the multiple-access channel with states, providing a new achievable rate region that outperforms traditional methods, especially in the doubly-dirty MAC scenario.

## Contribution

The paper presents a new achievable rate region for MAC with states using quasi-group codes, including a computable single-letter characterization and improved sum-rate performance.

## Key findings

- Achieves sum-rate of 1 bit per channel use in doubly-dirty MAC.
- Outperforms Gel'fand-Pinsker extension, which maxes at 0.32 bits.
- Provides a new coding scheme with a computable rate region.

## Abstract

The problem of reliable communication over the multiple-access channel (MAC) with states is investigated. We propose a new coding scheme for this problem which uses quasi-group codes (QGC). We derive a new computable single-letter characterization of the achievable rate region. As an example, we investigate the problem of doubly-dirty MAC with modulo-$4$ addition. It is shown that the sum-rate $R_1+R_2=1$ bits per channel use is achievable using the new scheme. Whereas, the natural extension of the Gel'fand-Pinsker scheme, sum-rates greater than $0.32$ are not achievable.