Selective Competition for NOMA-capable Devices Using RIS

The number of Internet of Things (IoT) devices which can be utilized in various smart applications is increasing significantly. Thus, a Medium Access Control (MAC) protocol is required for low-power operation when there are massive number of IoT devices with battery-limited characteristics. In a Wireless Local Area Network (WLAN) with IoT devices, it is difficult to utilize the Non-Orthogonal Multiple Access (NOMA) method as the Access Point (AP) cannot control the operation of distributed transmissions of devices. In this paper, we propose a MAC protocol in which the AP designate the NOMA-capable devices to utilize the NOMA method. We also employ the Reconfigurable Intelligent Surface (RIS) to increase the number of NOMA-capable devices participating in the competition. Through simulations, we can confirm that the throughput of the proposed protocol can be improved compared with the conventional method.