Intelligent Reconfigurable Surfaces vs. Decode-and-Forward: What is the Impact of Electromagnetic Interference?

TL;DR

This paper compares intelligent reconfigurable surfaces (IRS) and decode-and-forward (DF) relays in wireless systems under electromagnetic interference, showing IRS is more resilient to EMI and that DF requires multiple antennas and beamforming to compete.

Contribution

It introduces a comparison of IRS and DF relays considering electromagnetic interference, highlighting IRS's robustness and the need for advanced techniques for DF to match IRS performance.

Findings

EMI significantly impacts DF relay communications.

IRS demonstrates greater resilience to electromagnetic interference.

DF relays need multiple antennas and beamforming to counter EMI.

Abstract

This paper considers the use of an intelligent reconfigurable surface (IRS) to aid wireless communication systems. The main goal is to compare this emerging technology with conventional decode-and-forward (DF) relaying. Unlike prior comparisons, we assume that electromagnetic interference (EMI), consisting of incoming waves from external sources, is present at the location where the IRS or DF relay are placed. The analysis, in terms of minimizing the total transmit power, shows that EMI has a strong impact on DF relay-assisted communications, even when the relaying protocol is optimized against EMI. It turns out that IRS-aided communications is more resilient to EMI. To beat an IRS, we show that the DF relay must use multiple antennas and actively suppress the EMI by beamforming.