RIS-Aided Communications over Dirty MAC: Capacity Region and Outage Probability

TL;DR

This paper analyzes the capacity region and outage probability of RIS-assisted two-user MAC systems with side information, demonstrating that RISs enhance capacity and reliability in interference-limited scenarios.

Contribution

It derives closed-form expressions for capacity and outage probability in RIS-aided MACs with side information, covering scenarios with different interference knowledge.

Findings

RISs extend the capacity region.

RISs improve outage probability.

Closed-form expressions for capacity and outage probability.

Abstract

We characterize the capacity region of a two-user multiple access channel (MAC) in a reconfigurable intelligent surface (RIS)-aided communication system with side information (SI) at the transmitters. We consider two uplink communication scenarios: (i) a double dirty MAC where the interferences are known non-causally to both users; and (ii) a single dirty MAC model where only one of the users knows the interference and the other one is not aware of the interference. Considering that each of the users is assisted by a different RIS with Mi elements, we derive closed-form expressions for the capacity region and the outage probability (OP) for both system models. Results show that the use of RISs is beneficial to extend the capacity region and improve the OP in both scenarios.