Rate Maximization of Cell-Edge Users Through Cooperative Non-Orthogonal Multiple Access

The conventional standards may not support massive connectivity and offer poor rate for cell-edge users. To serve a greater number of devices and sensors, non-orthogonal multiple access (NOMA) is introduced, where multiple users can be served with same frequency at the same time. The conventional NOMA allocates more power to cell-edge user than near user. To enhance the rate of cell-edge user further, cooperative NOMA (CNOMA) is proposed, where the near user acts like a relay and retransmits cell-edge user’s data. This enhances signal strength at cell-edge user through selection diversity. CNOMA surpasses conventional NOMA and orthogonal multiple access (OMA) in outage probability and sum rate, which is proved through simulations.