Reconfigurable Intelligent Surfaces Assisted Communications With Limited Phase Shifts: How Many Phase Shifts Are Enough?

• Published in: IEEE transactions on vehicular technology Vol. 69; no. 4; pp. 4498 - 4502
• Main Authors: Zhang, Hongliang, Di, Boya, Song, Lingyang, Han, Zhu
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Channel models; Communications systems; Degradation; Encoding; limited phase shifts; Manganese; performance analysis; Performance degradation; Performance evaluation; Reconfigurable intelligent surfaces; Reconfigurable intelligent surfaces assisted communications; Signal to noise ratio; Uplink; Wireless communication
• ISSN: 0018-9545; 1939-9359
• DOI: 10.1109/TVT.2020.2973073

Reconfigurable intelligent surface (RIS) has drawn a great attention worldwide as it can create favorable propagation conditions by controlling the phase shifts of the reflected signals at the surface to enhance the communication quality. However, the practical RIS only has limited phase shifts, which will lead to the performance degradation. In this paper, we evaluate the performance of an uplink RIS assisted communication system by giving an approximation of the achievable data rate, and investigate the effect of limited phase shifts on the data rate. In particular, we derive the required number of phase shifts under a data rate degradation constraint. Numerical results verify our analysis.