Indonesian Journal of Electrical Engineering and Computer Science Vol. 25, No. 1, January 2022, pp. 358∼364 ISSN: 2502-4752, DOI: 10.11591/ijeecs.v25.i1.pp358-364 ❒ 358 Reconfigurable intelligent surfaces assisted wireless communication networks: ergodic capacity and symbol error rate Dinh-Thuan Do, Chi-Bao Le Faculty of Electronics Technology, Industrial University of Ho Chi Minh City, Ho Chi Minh City, Vietnam Article Info Article history: Received Apr 19, 2021 Revised Nov 15, 2021 Accepted Nov 25, 2021 Keywords: Ergodic capacity Reconfigurable intelligent surfaces Symbol error rate ABSTRACT By enabling reconfigurable intelligent surfaces (RIS), we can deploy intelligent re- flecting signals from the base station to destinations. Different from traditional relay- ing system, RIS relies on programmable metasurfaces and mirrors to improve system performance of destinations. We derive the formulas of main system performance metrics such as ergodic capacity and symbol error rate (SER). Based on types of mod- ulation, we need to demonstrate other parameters which make influence to system per- formance. We show analytically that the number of reflecting elements along with the transmit power at the source can improve system performance. Moreover, we check the exactness of derived expressions by matching Monte-Carlo with analytical simu- lations. Finally, we find the best performance can be achieved at specific parameters and results are verified by explicit simulations. This is an open access article under the CC BY-SA license. Corresponding Author: Dinh-Thuan Do Faculty of Electronics Technology, Industrial University of Ho Chi Minh City 12 Nguyen Van Bao Street, Go Vap District, Ho Chi Minh City 700000, Vietnam Email: dodinhthuan@iuh.edu.vn 1. INTRODUCTION To implement next-generation wireless communications, one can deploy reconfigurable intelligent surfaces (RISs) to enable current systems with solid requirements such as low cost, high energy-efficiency and higher bandwidth efficiency. RISs exhibit their appealing ability by adjusting the propagation of the electro- magnetic waves [1]–[3]. By integrating of passive and reflecting units, the RIS-aided systems can adjust phases and amplitudes independently for the incident signals. Further, RIS provides a massive connections and ex- ploits a full-duplex scheme to reflect signals to destinations. As main advances, the RIS shows benefits when we compare it with the contemporary relaying systems. First, to avoid power-hungry radio frequency process- ing, the RIS is deployed as a passive device and thus less energy is acquired to conduct the reflection. Second, to introduce low-cost deployment, the RIS can be easily deployed on various environmental objects, for ex- ample building facades, street signs and advertisement boards [4]. Furthermore, in perceptive of information transfer, the reflection pattern is implemented at the RIS to improve system performance [5]–[7]. Specifically, Rehman et al. [8] studied expressions of the outage probability and average sum-rate by assuming that the RIS-aided system is optimized when the system can achieve the highest instantaneous end-to-end signal-to-noise ratio (SNR). RIS thus is deployed to improve the current systems in terms of in- terference cancellation, secure transmission, wireless coverage, throughput enhancement, wireless information and power transfer. Importantly, Pan et al. [9] proposed the system to allow the angle of reflection of each RIS Journal homepage: http://ijeecs.iaescore.com