Closed-Form Pathloss Formulation for IRS-Assisted 6G Wireless Networks

Intelligent reflecting surfaces (IRSs) are smart devices that can manipulate electromagnetic wave propagation to optimize performance of future 6G wireless networks. In IRS-assisted wireless communications, one of the most important performance metrics to optimize is the received signal-to-noise ratio (SNR). As the SNR depends on the received signal power, it is thus dependent on the underlying path loss (PL) of the wireless channel. There exist dozens of PL formulations for wireless links facilitated through an IRS. However, IRS-assisted wireless communications comprise of a transmitter (Tx)-Receiver (Rx) link together with the one through the IRS, that is, the Tx-IRS-Rx link. The Tx-Rx and Tx-IRS-Rx links are subject to different PL formulations. The PL of the complete wireless channel comprised of both links has never been formulated. The latter constitutes the subject of this paper, where we present a closed-form PL solution for IRS-assisted wireless communications comprised of both Tx-Rx and Tx-IRS-Rx links. The presented solution is subject to the PLs of the individual links and demonstrates the great benefit that IRSs can have on overall PL reduction.