The Emergence of Multi-Functional and ”Truly Active” Reconfigurable Intelligent Surfaces for Location-Aware Communications. A Survey

Reconfigurable Intelligent Surfaces (RIS) are positioned as the key enabling technology for 6G networks as they provide ubiquitous coverage for areas with blocked LoS links. However, it is predicted that to be successful, such structures will require integration of sensors and radio network elements, therefore resulting in a Multi-Functional RIS. This Survey provides the up to date summary of state of the art and considers applications for such structures as well as the challenges associated with RIS deployment. A novel concept of Location Aware Smart Wireless Environment (LASWE) is proposed to satisfy the future demands of 6G, by utilising digitally-controlled low-cost metasurfaces with integrated sensing elements and energy harvesting techniques for power autonomous operation.