Designing the phase shifts of a reconfigurable intelligent surface for positioning

Abstract

Reconfigurable Intelligent Surface is becoming an emerging and promising technology, which can assist 5G communication networks to achieve a better performance. RIS is a planar surface consisting of a vast number of adjustable elements, where each element can reflect the incident wave towards the expected direction and thus create an electromagnetically preferred propagation environment. Besides, as 5G networks are considered to be the first generation to benefit greatly from positioning information, the design of localization system is also drawing attention from groups of researchers. Therefore, this dissertation attempts to explore the behavior of the RIS when it is applied in a positioning system. Specifically, how the phase shift of RIS will affect the localization performance will be studied based on the derivation of Cramér-Rao lower bound in order to find the theoretical bound of the estimation error. The dissertation will also discuss the difference in performance when there are multiple users instead of a single user.