While intelligent reflecting surface (IRS) assisted wireless communication has emerged as an important research paradigm, channel state information (CSI) acquisition remains a critical challenge to design the IRS phase-shifts and yield the promised coherent beamforming gains. In this letter, we propose an IRS-assisted opportunistic beamforming (OBF) scheme under proportional fair scheduling, which does not require instantaneous CSI to design the IRS parameters. In a slow-fading environment, we show that with only random rotations at the IRS, the proposed scheme can capitalize on the multi-user (MU)-diversity effect to approach the performance of coherent beamforming as the number of users grows large. Next we study the sum-rate scaling of IRS-assisted OBF in the correlated Rayleigh fast fading environment under a deterministic beamforming scheme that results in a considerable sum-rate improvement.
Bibliographical noteKAUST Repository Item: Exported on 2021-02-09
Acknowledged KAUST grant number(s): OSR-2018-CRG7-3734.
Acknowledgements: This work was supported by the King Abdullah University of Science andTechnology (KAUST) under Award OSR-2018-CRG7-3734.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.