A Survey on Application of Non-Orthogonal Multiple Access to Different Wireless Networks

Abstract

The fifth generation (5G) wireless systems are anticipated to meet unprecedented capacity and latency requirements. In order to resolve these challenges in 5G, non-orthogonal multiple access (NOMA) is considered as a promising technique due to its ability to enhance spectrum efficiency and user access. As opposed to conventional orthogonal multiple access (OMA) which relies on orthogonal resource sharing, NOMA has a potential of supporting a higher number of users by multiplexing different users in the same resource in a non-orthogonal manner. With advanced receiver techniques, such as successive interference cancellation (SIC), the intra-user interference can be minimized at the NOMA receiver. To date, there are comprehensive surveys on NOMA, which describe the integration of NOMA with different communication technologies and discuss different NOMA classifications. However, the existing literature is scarce in reviewing state-of-the-art applications of NOMA from the perspective of its application to cellular networks (CNs), device-to-device (D2D) communications, and wireless sensor networks (WSNs). Therefore, the purpose of this survey is to fill this gap in knowledge. Specifically, NOMA with its underlying concepts are elaborated in detail. In addition, detailed system model of different NOMA-based wireless networks is presented. Furthermore, irrespective of the underlying spatial topology of the considered NOMA-based wireless network, general analytical expressions are presented to characterize the network performance. Finally, some challenges related to NOMA design are highlighted and potential research directions are pointed out to address these issues.

Sparse Code Multiple Access: Potentials and Challenges

“…The authors in [21] provides a comprehensive survey of the interplay between PD-NOMA and some emerging technologies such as massive multiple-input multiple-output (MIMO), millimeter wave (mmWave), energy harvesting, wireless caching, and so on. In [23], PD-NOMA applications to wireless networks, including cellular networks, device-todevice communications and wireless sensor networks, was reviewed. Also, recent advances in NOMA from a grant-free access perspective were comprehensively discussed in [22].…”

“…Comparison study between PD-NOMA and SCMA in [63] showed that SCMA outperforms PD-NOMA when comparable resources allocation strategies for heterogeneous cellular networks are employed. This gain in performance is at the expense of more complexity where SIC method is used to separate signals in the PD-NOMA case while the more sophisticated MPA one is used for SCMA systems, the later costs more in terms of operations and materials [23]. That is why a lot of research work was conducted to reduce the complexity of SCMA detectors as it will be shown in Section IV, however additional future contributions are expected to further enhance this aspect.…”

Best Relay Selection Schemes for NOMA Based Cognitive Relay Networks in Underlay Spectrum Sharing

“…In this work, since the best relay enables the end-to-end communication for U 2 only, therefore to proceed further, U 2 and x 2 can be dropped in the above Eq., for the simplicity of notation, i.e. Γ j ≤ Γ Rj (10) where, Γ Rj is the SNR of the j th R j − U 2 link. Proceeding towards the mathematical formulation of the BRS problem, the conventional max-min relay selection in the traditional non-cognitive relay networks can be conducted based on the single rule of j = max j=1,2,...,J…”

“…Besides cognitive radio technique, NOMA being the latest technology trend is promising to realize the aggressive 5G goal through multiplexing multiple users in power domain over the same resource block (frequency/time/code). Conventional mobile networks have been relying on OMA techniques that follow the principle of user orthogonality in frequency/time/code domain and enable single user in each resource block [9]- [10]. The disjoint resource allocation in OMA minimizes inter-user interference however does not hold the spectral efficiency required to support the demands of future generation networks.…”

Cooperative Secure Transmission in MISO-NOMA Networks

“…Non-orthogonal multiple access (NOMA), which has shown the potential to significantly improve spectral efficiency, is envisaged as a promising technique for the 5G wireless networks [1,2]. In contrast to the conventional orthogonal multiple access (OMA), NOMA exploits the power domain to serve multiple users simultaneously [3].…”