Comparison of Slotted Aloha-NOMA and CSMA/CA for M2M Communications in IoT Networks

Abstract

The Internet of things (IoT), which is the network of physical devices embedded with sensors, actuators, and connectivity, is being accelerated into the mainstream by the emergence of 5G wireless networking and the support of Machine-to-Machine (M2M) communications. Due to the simplicity of IoT devices and their sporadic traffic in such application, a simple medium access control (MAC) protocol is needed to connect M2M devices to the Internet through a hub (IoT gateway). This paper compares two MAC protocols namely: the newly introduced slotted Aloha-NOMA protocol and the well-known carrier sensing multiple access with collision avoidance (CSMA/CA) protocol. The comparison is based on two metrics, the throughput and the average delay. Simulation results show that the throughput of slotted Aloha-NOMA is higher than CSMA/CA at low probability of transmission at the cost of increased average delay caused by novel power level selection mechanism.