NOMA with energy harvesting using reconfigurable intelligent surfaces for Nakagami channels

In this paper, we suggest to increase the throughput of Non Orthogonal Multiple Access (NOMA) with energy harvesting. The source harvests energy using the received Radio Frequency signal from node A. Reconfigurable Intelligent Surfaces (RIS) are placed between the source and NOMA users. Different sets of reflectors are dedicated to the different users. The reflected signals have the same phase at any user resulting in significant performance enhancement with respect to NOMA systems without RIS. We optimize the powers allocated to NOMA users and harvesting duration to maximize the total throughput. We also suggest the use of two RIS. The first RIS is located between node A and the source to improve the energy harvesting process. The second RIS reflects the source signal toward NOMA users. Our derivations are valid for Nakagami channels.