Distributed IRS-aided DF relaying systems: Performance analysis and optimization

Intelligent reflecting surface (IRS) is a newly emerged and promising paradigm to substantially improve the performance of wireless communications by constructing favorable communication channels via properly tuning massive reflecting elements. This paper considers a distributed IRS aided decode-and-forward (DF) relaying system over Nakagami-m fading channels. Based on a tight approximation for the distribution of the received signal-to-noise ratio (SNR), we first derive exact closed-form expressions of the outage probability, ergodic capacity, and energy efficiency for the considered system. Moreover, we propose the optimal IRS configuration considering the energy efficiency and pilot overhead. Finally, we compare the performance between the distributed IRS-aided DF relaying and multi-IRS-only systems, and verify the analytical results by using monte carlo simulations.