Spectral and Energy Efficiency of IRS-Assisted MISO Communication With Hardware Impairments

• Published in: IEEE wireless communications letters Vol. 9; no. 9; pp. 1366 - 1369
• Main Authors: Zhou, Shaoqing, Xu, Wei, Wang, Kezhi, Di Renzo, Marco, Alouini, Mohamed-Slim
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.09.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); IEEE comsoc
• Subjects: Array signal processing; Computer simulation; Downlink; Energy efficiency; Engineering Sciences; Hardware; hardware impairments; Intelligent reflecting surface; MISO (control systems); MISO communication; Optimization; Performance degradation; Phase noise; Radio frequency; Signal and Image processing; Signal to noise ratio; Spectra; spectral efficiency; Intelligent reflecting surface; hardware impairments; spectral efficiency; energy efficiency; downlink spectral efficiency
• ISSN: 2162-2337; 2162-2345
• DOI: 10.1109/LWC.2020.2990431

In this letter, we analyze the spectral and energy efficiency of an intelligent reflecting surface (IRS)-assisted multiple-input single-output (MISO) downlink system with hardware impairments. An extended error vector magnitude (EEVM) model is utilized to characterize the impact of radio-frequency (RF) impairments at the access point (AP) and phase noise is considered at the IRS. We show that the spectral efficiency is limited due to the hardware impairments even when the numbers of AP antennas and IRS elements grow infinitely large, which is in contrast with the conventional case with ideal hardware. Moreover, the performance degradation at high SNR is shown to be mainly affected by the AP hardware impairments rather than by the phase noise at the IRS. We further obtain in closed form the optimal transmit power for energy efficiency maximization. Simulation results are provided to verify the obtained results.