NOMA in Cooperative Communication Systems With Energy-Harvesting Nodes and Wireless Secure Transmission

In this paper, non-orthogonal multiple access (NOMA) in cooperative relay system is considered, where a source node communicates with pair of energy harvesting (EH) user equipments through antennas node. A hybrid protocol adopted at the relay, which if can successfully decode signals, decode-and-forward (DF) will be to forward signals users. Otherwise, amplify-and-forward (AF) implemented. Assuming that users adopt maximal ratio combining (MRC) combine received two phases, new explicit analytical expressions for average sum-rate are derived when works in, 1) AF mode, and 2) DF scenarios one stronger both cooperation an alternative each phase. Then, investigation extended case untrusted node, jamming technique proposed degrade ability enforce operate always mode. For scenario, expression secrecy rate derived. Monte Carlo simulations provided validate analysis. The simulation results reveal location key parameter achieve best performance.