A Survey of Non-orthogonal Multiple Access for Internet of Things and Future Wireless Networks

Non-orthogonal multiple access (NOMA) is an effective multiple access technique for future generations of wireless networks. It has large spectral efficiency, enabling high connectivity, which is essential for Internet of Things (IoT) applications. IoT applications initiate an industrial and user revolution era with massive connected devices. This paper discusses various NOMA schemes for IoT applications and their implementation for massive IoT networks. It also describes the current limitations of NOMA for IoT, including security, successive interference cancellation (SIC), power allocation, and channel estimation. Various deep learning applications along with a comprehensive study of several promising technologies for massive wireless connectivity, millimeter-wave (mmWave), massive multiple input multiple output (mMIMO), and unmanned aerial vehicles (UAV) communication are also illustrated based on NOMA-IoT applications.