Application of Non-Orthogonal Multiple Access in LTE and 5G Networks

Abstract

As the latest member of the multiple access family, non-orthogonal multiple access (NOMA) has been recently proposed for 3GPP Long Term Evolution (LTE) and envisioned to be an essential component of 5th generation (5G) mobile networks. The key feature of NOMA is to serve multiple users at the same time/frequency/code, but with different power levels, which yields a significant spectral efficiency gain over conventional orthogonal MA. The article provides a systematic treatment of this newly emerging technology, from its combination with multiple-input multiple-output (MIMO) technologies, to cooperative NOMA, as well as the interplay between NOMA and cognitive radio. This article also reviews the state of the art in the standardization activities concerning the implementation of NOMA in LTE and 5G networks.

Resource Allocation in Non-Orthogonal and Hybrid Multiple Access System With Proportional Rate Constraint

“…In 4G networks, orthogonal multiple access is used as the air interface technique and proved its effectiveness against multi-path fading and achieving high system throughput. However, it does not make full use of the spectral resource as it restricts each user to use a limited part of the spectrum, which makes it insufficient to enhance the spectral efficiency and the capacity of future networks [1]- [5]. Recently, non-orthogonal multiple access (NOMA) is presented as a promising radio access scheme for further capacity enhancement and to accommodate the future traffic demand.…”

IoT’s Tiny Steps towards 5G: Telco’s Perspective

“…They include several non-orthogonal multiple access (NOMA) forms: multi-user shared multiple access (MUSA) [145][146][147][148], resource spread multiple access (RSMA) [149], sparse code multiple access (SCMA) [150][151][152], pattern division multiple access (PDMA) [153][154][155], interleave-division multiple access (IDMA) [156,157], and NOMA by power domain [158]. The NOMA is a radio access technology design for enabling greater spectrum efficiency [56,[159][160][161][162]207], higher cell-edge throughput, relaxed channel feedback, and low transmission latency [99]. NOMA can be employed to enhance user fairness and to support massive connections with diverse QoS requirements [163].…”

Energy optimization for full-duplex self-backhauled HetNet with non-orthogonal multiple access

“…To mitigate the complexity of signal processing at the UE side, we consider no cooperative communications at the UEs, and treat the first weak signal from the MBS→UE link as noise. According to the basis of NOMA [4]- [6], the decoding order in cluster c is predefined as the descending order of [5]. We use b c (k) to indicate the position of UE k ∈ K c in the sorted sequence in cluster c. Thus, UE k in cluster c before decoding its desired signal x k , first decodes and subtracts the received signals x j in {j ∈ K c \{k} : b c (j ) > b c (k)}.…”

“…To improve spectrum efficiency and mitigate co-channel interference, power-domain non-orthogonal multiple access (NOMA), has been proposed for 5G systems [4], [5]. In downlink, NOMA is enabled by superposition coding at the transmitter, and relying on multi-user detection (MUD) and successive interference cancellation (SIC) at the receivers to remove some of the co-channel interference [6].…”

“…Motivations and contributions are summarized below: 1) we investigate a NOMA based scheme for FS-HetNet to jointly optimize the energy consumption in data transmission and in SIC decoding operations, which has not been fully investigated in the literature. 2) in previous works, the UE grouping/clustering schemes in NOMA are typically heuristic, e.g., randomly grouping UEs to a channel, paring two UEs with best-worst channel gains [4], [5]. The performance of NOMA largely depends on the decisions of which UEs are scheduled to the same channel simultaneously and their power allocation.…”