Uplink non-orthogonal multiple access for 5G wireless networks

By Mohammed Al-Imari, P. Xiao, Muhammad Ali Imran, Rahim Tafazolli. International Symposium on Wireless Communication Systems, 2014

357 citations recorded by the source corpus.

Orthogonal Frequency Division Multiple Access (OFDMA) as well as other orthogonal multiple access techniques fail to achieve the system capacity limit in the uplink due to the exclusivity in resource allocation. This issue is more prominent when fairness among the users is considered in the system. Current Non-Orthogonal Multiple Access (NOMA) techniques introduce redundancy by coding/spreading to facilitate the users' signals separation at the receiver, which degrade the system spectral efficiency. Hence, in order to achieve higher capacity, more efficient NOMA schemes need to be developed. In this paper, we propose a NOMA scheme for uplink that removes the resource allocation exclusivity and allows more than one user to share the same subcarrier without any coding/spreading redundancy. Joint processing is implemented at the receiver to detect the users' signals. However, to control the receiver complexity, an upper limit on the number of users per subcarrier needs to be imposed. In addition, a novel subcarrier and power allocation algorithm is proposed for the new NOMA scheme that maximizes the users' sum-rate. The link-level performance evaluation has shown that the proposed scheme achieves bit error rate close to the single-user case. Numerical results show that the proposed NOMA scheme can significantly improve the system performance in terms of spectral efficiency and fairness comparing to OFDMA.

Subfields: Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/0837ce7a3504ecb25b8ac903b342871e7fd3435d

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Citations in the corpus

Nonorthogonal Multiple Access for 5G and Beyond (2017, methodology): “Motivated by this, many NOMA contributions characterized their PA in terms of Jain’s fairness index [103], [108], [163].”
The Application of MIMO to Non-Orthogonal Multiple Access (2015, methodology): “m conventional orthogonal multiple access (OMA) schemes. In [7] the implementation of NOMA has been considered in a scenario with two base stations, and the design of uplink NOMA has been proposed in [8]. The user fairness of NOMA has been considered in [9] by studying the impact of different choice”
Power and Channel Allocation for Non-Orthogonal Multiple Access in 5G Systems: Tractability and Computation (2016, methodology): “The existing resource allocation approaches for NOMA are typically carried out with fixed power allocation [13], [15], [17], predefined user set for subchannels [10], or parameter tuning to improve performance, e.”
Impact of User Pairing on 5G Nonorthogonal Multiple-Access Downlink Transmissions (2016, methodology): “The design of NOMA for uplink transmissions has been proposed in [4], and the performance of NOMA with randomly deployed mobile stations has been characterized in [5].”
Nonorthogonal Multiple Access in Large-Scale Underlay Cognitive Radio Networks (2016, methodology): “A downlink NOMA and an uplink NOMA are considered in [2] and [3], respectively.”
A General Power Allocation Scheme to Guarantee Quality of Service in Downlink and Uplink NOMA Systems (2016, methodology): “The performance of uplink NOMA transmission was studied in [6].”
On the Performance of Non-orthogonal Multiple Access Systems With Partial Channel Information (2016, unknown): “In [7], the uplink communication of NOMA systems has been considered, while the impact of user pairing in NOMA systems over small-scale fading, with fixed and cognitive radio inspired power allocation, has been investigated in [8].”
Exploiting Full/Half-Duplex User Relaying in NOMA Systems (2018, methodology): “So far, point-to-point NOMA has been studied extensively in [10–14].”
A General MIMO Framework for NOMA Downlink and Uplink Transmission Based on Signal Alignment (2015, unknown): “imized under different channel state information (CSI) assumptions. In [8], topological interference management has been applied for single-antenna downlink NOMA transmission. Unlike the above works, [9] addressed the application of NOMA for uplink transmission, where the problems of power allocatio”
Dynamic User Clustering and Power Allocation for Uplink and Downlink Non-Orthogonal Multiple Access (NOMA) Systems (2016, background): “A joint subcarrier and power allocation problem was studied in [11].”