A novel MAC protocol with independent double-pilot scheme and NOMA for MTC in IoT networks

Abstract

With the rapid growth of IoT devices, machine communication is becoming more and more popular in 5G wireless communication systems. This paper proposes a novel MAC protocol for the Internet of Things (IoT) in a scenario with a gateway and multiple IoT devices. The IoT devices with packets (active IoT devices) send independent double-pilot(IDP). The gateway takes the number and ID of IoT devices and allocates appropriate power to IoT devices. These IoT devices adjust the power and transmit packets using the Power domain Non-Orthogonal Multiple Access Protocol (PD-NOMA). Compared with the traditional single pilot scheme (TSP), the independent double-pilot can dramatically reduce the pilot collision probability, although it will probably bring a moderate increase in detection workload. Furthermore, the IDP-NOMA protocol proposed in this paper dramatically improves the system throughput and the probability of transmission success.