SER performance of millimeter-wave communications with multiple reconfigurable intelligent surfaces and transmit antenna selection

Abstract

This paper proposes a combination of transmit antenna selection (TAS) scheme and multiple reconfigurable intelligent surfaces (RISs) for significantly reducing the symbol error rate (SER) of the millimeter-wave (MW) communications. In particular, TAS scheme is applied to dramatically decrease the computational complexity in the multi-RIS-aided MW communications. The SER formula of the multi-RIS-aided MW communications with TAS is derived over Nakagami-m channels. Then, it is validated through Monte-Carlo simulations. Numerical results confirm the joint and separate benefits of TAS scheme and multi-RIS in the MW communications. Specifically, the SER of the multi-RIS-aided MW communications with TAS is considerably lower than SER of multi-RIS-aided MW communications without TAS. Consequently, applying TAS can dramatically decrease the transmit power of the transmitter in comparison with the case without TAS when the SER target is a constant. Moreover, the SERs of multi-RIS-aided MW communications with and without TAS are much lower than those of MW communications without RISs in the cases with and without RISs, respectively. Besides these features, many methods such as an increase in the number of transmit antennas, a suitable choice of carrier frequencies in MW bands, and the appropriate locations of the RISs’ positions for performance enhancement of multi-RIS-aided MW communications with TAS are investigated.