SWIPT-NOMA in Cell-Free Massive MIMO

In this paper, the performance of a Simultaneously Wireless Information and Power Transfer combined with the Non-Orthogonal Multiple Access (SWIPT-NOMA) in a cell-free massive MIMO (CFMM) network is evaluated, where users are authorized to decode data as well as harvest power simultaneously. More specifically, each cluster-head serves as a relay in order to decode the received signal and forward it to the second user in each cluster by using harvested energy. In particular, a simple two user pairing algorithm is proposed for each cluster in the designed system. Furthermore, imperfect Channel State Information (CSI), pilot contamination as well as Successive Interference Cancellation (SIC) error propagation are considered. In particular, the ergodic net-sum-rate is obtained, and simulation results show a better performance for the SWIPT-NOMA at the cost of excess in the number of antennas at each user and obtaining prefect information of user's location and channel gain at Access Points (APs) and each cluster head, respectively.