Reflection Design Methods for Reconfigurable Intelligent Surfaces-Aided Dynamic TDD Systems

Dynamic time-division-duplexing (DTDD) and reconfigurable intelligent surfaces (RISs) have been proposed recently as solutions to meet the small cells traffic fluctuations and to tune the wireless propagation channels in real-time, respectively. However, to the best of the authors' knowledge, there has been no work so far considering the integration of both techniques. Therefore, we consider in this paper an RIS-aided DTDD wireless system and propose two non-iterative methods to design the RIS reflection vector with the objective of maximizing the system spectral efficiency, while reducing the cross-link interference. Numerical results are presented showing the efficiency of the proposed methods as compared to some baseline schemes. It is shown that the integration of RIS in DTDD systems has great potential in improving communication efficiency while reducing the impact of cross-link interference.