User Assignment for Wireless Communication Assisted by Reconfigurable Intelligent Surfaces

The Reconfigurable Intelligent Surface (RIS) is a new and cost-effective solution for achieving high energy efficiency through massive low-cost passive elements. In the far field case, a lot of work are carried out on the assumption that the center of RIS is the reflection point. In the case of multi-user far field, the difference of user positions will increase the power consumption of Base Station (BS). Users and RIS cells are matched by resorting to Kuhn-Munkres (KM) algorithm in this paper, taking the transmitting power of BS as cost matrix. Under the constraints of SNR, the transmitting power of BS can be reduced by the user assignment method. Simulation results show that the matching method between users and RIS units adopted in this paper can reduce BS power consumption by up to 1% compared with random units of RIS.