A Fast and Efficient Codebook-Based RIS Phase Configuration Method

Reconfigurable Intelligent Surfaces (RISs) consist of large array of low-cost passive elements that can be configured in real-time to alter the wavefront of incident electromagnetic waves and enhance communication system performances. However, as the number of RIS elements increases the RIS phase configuration overhead also increases. To reduce this overhead, a codebook-based approach can be used where the RIS is preset with a limited number of configurations. However, the selection of the quasi-optimal configuration, from the set of available predefined configurations, still presents a relatively high overhead. In this paper, we propose a multi-level multi-width beam sweeping method for fast, efficient and low-overhead RIS configuration.