A Systematic Review on NOMA Variants for 5G and Beyond

Abstract

Over the last few years, interference has been a major hurdle for successfully implementing various end-user applications in the fifth-generation (5G) of wireless networks. During this era, several communication protocols and standards have been developed and used by the community. However, interference persists, keeping given quality of service (QoS) provision to end-users for different 5G applications. To mitigate the issues mentioned above, in this paper, we present an in-depth survey of state-ofthe-art non-orthogonal multiple access (NOMA) variants having power and code domains as the backbone for interference mitigation, resource allocations, and QoS management in the 5G environment. These are future smart communication and supported by device-to-device (D2D), cooperative communication (CC), multiple-input and multiple-output (MIMO), and heterogeneous networks (HetNets). From the existing literature, it has been observed that NOMA can resolve most of the issues in the existing proposals to provide contention-based grant-free transmissions between different devices. The key differences between the orthogonal multiple access (OMA) and NOMA in 5G are also discussed in detail. Moreover, several open issues and research challenges of NOMA-based applications are analyzed. Finally, a comparative analysis of different existing proposals is also discussed to provide deep insights to the readers.

Energy-Efficient Resource Allocation for NOMA-Based Heterogeneous 5G Mine Internet of Things

“…However, the connection scale and transmission performance in NOMA systems largely depends on the resource allocation scheme [18]. Moreover, heterogeneous network (HetNet) [19], as a promising network infrastructure in 5G, can not only enhance the network capacity and user experience of the edge cell, but also reduce coverage blind spots and improve the transmission performance of communication systems. The traditional HetNet is mainly composed of two types of base stations (BSs), namely macro base station (MBS) and small base station (SBS) [20].…”

Successive Interference Cancellation Decoding With Adaptable Decision Regions for NOMA Schemes

“…Channel resource sharing techniques have been gaining importance due to the necessity of achieving higher spectral efficiency in the next generations of wireless communications systems [1]. Among them, power domain non-orthogonal multiple access (NOMA) is an important technique in accomplishing this task [2], which is also frequently linked to 5G technologies [3]. In this scheme, signals from multiple users with different power levels share the same channel resources, and the successive interference cancellation (SIC) is the usual decoding method, in which the decoding at each user is performed sequentially according to the ordering of their power levels.…”

A Machine Learning Adaptive Beamforming Framework for 5G Millimeter Wave Massive MIMO Multicellular Networks

“…The massive deployment of fifth-generation (5G) broadband wireless cellular networks has enabled the transition towards advanced features and services, such as ultra-reliable low latency communications (URLLC), enhanced mobile broadband as well as massive machine type communications (mMTC) [1], [2]. In this context, various novel technologies have been developed in the physical layer, such as nonorthogonal multiple access (NOMA) [3], that can leverage spectral efficiency (SE), milimmiter wave (mmWave) trans-mission [4], as well as massive multiple input multiple output (m-MIMO) configurations [5]. In the latter case, a very large number of transmitting antennas is deployed over various access points (APs) of the wireless orientation in order to support high data rate transmission in multiple mobile stations (MSs) as well as seamless end-to-end connectivity.…”