Joint User Pairing, Channel Assignment and Power Allocation in NOMA based CR Systems

Ali, Zain; Rao, Yanyi; Khan, Wali Ullah; Sidhu, Guftaar Ahmad Sardar

doi:10.3390/app9204282

Cited by 20 publications

(10 citation statements)

References 33 publications

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“…In general, we note an increase in the when the number of vehicles in the network grows. This improvement can be attributed to the improvement in diversity gains ensure by (6). As a result of a decrease in value of α does not influence the performance of the vehicular network much when the number of vehicles is large.…”

Section: Performance Evaluationmentioning

confidence: 98%

“…Due to the ever-present constraint of spectral resources, non-orthogonal multiple access (NOMA) has attracted the interest of researchers as an alternative to orthogonal multiple access (OMA) [4], [5]. Using the power variations at the transmitter side, NOMA supports multiple users over the same spectrum resource [6]. Then, the successive interference cancellation (SIC) is used at the receiver side to decode different signals [7].…”

Section: Introductionmentioning

confidence: 99%

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Multiobjective Optimization of Uplink NOMA-Enabled Vehicle-to-Infrastructure Communication

et al. 2020

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Vehicular communication is gradually evolving from the rudimentary data exchange techniques to innovative, efficient, and large-scale communication platform. The future vehicular networks aim to offer new services and achieve massive connectivity with the aid of advanced wireless communication techniques. In this regard, one of the emerging paradigms is non-orthogonal multiple access (NOMA) which holds the promise to meet the resource-intensive demands of future networks. Due to this reason, the applications of NOMA are being investigated by the researcher of academia and industry alike. This article aims to build on the state-of-the-art by providing a novel multiobjective optimization framework for vehicle-to-infrastructure (V2I) communications. Specifically, this work aims to improve upon the sum-rate and energy efficiency of uplink NOMA-enabled V2I communications. The formulated problem is based on the tradeoff between sum-rate and total transmit power while maintaining the quality of service (QoS) requirements of the network. To provide a reliable solution, a multiobjective optimization framework has been proposed by applying the weighted-sum method and handle joint metrics of sum-rate maximization and total transmit power minimization. Extensive simulations have been performed to validate the superiority of the proposed framework against conventional benchmark techniques. The results clearly indicate that the proposed framework is feasible for NOMA-enabled V2I communication and can be scaled up for practical implementation. INDEX TERMS Non-orthogonal multiple access, multiobjective optimization, QoS, vehicular communication.

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Section: Performance Evaluationmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Multiobjective Optimization of Uplink NOMA-Enabled Vehicle-to-Infrastructure Communication

et al. 2020

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“…In addition, the design of minimum Euclidean distance (MED) precoders for MIMO-NOMA downlink is developed in [21], where MED precoders are extended to general multi-user scenarios. In addition, Ali et al proposed an efficient user pairing, channel assignment, and power optimization technique for the secondary users while primary users' performance is guaranteed through interference temperature limits [22]. Their solution maximizes the achievable rate of a multi-user multi-channel NOMA based cognitive radio system.…”

Section: Introductionmentioning

confidence: 99%

User Clustering and Power Allocation for Energy Efficiency Maximization in Downlink Non-Orthogonal Multiple Access Systems

et al. 2021

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Non-orthogonal multiple access (NOMA) has been considered a promising technique for the fifth generation (5G) mobile communication networks because of its high spectrum efficiency. In NOMA, by using successive interference cancellation (SIC) techniques at the receivers, multiple users with different channel gain can be multiplexed together in the same subchannel for concurrent transmission in the same spectrum. The simultaneously multiple transmission achieves high system throughput in NOMA. However, it also leads to more energy consumption, limiting its application in many energy-constrained scenarios. As a result, the enhancement of energy efficiency becomes a critical issue in NOMA systems. This paper focuses on efficient user clustering strategy and power allocation design of downlink NOMA systems. The energy efficiency maximization of downlink NOMA systems is formulated as an NP-hard optimization problem under maximum transmission power, minimum data transmission rate requirement, and SIC requirement. For the approximate solution with much lower complexity, we first exploit a quick suboptimal clustering method to assign each user to a subchannel. Given the user clustering result, the optimal power allocation problem is solved in two steps. By employing the Lagrangian multiplier method with Karush–Kuhn–Tucker optimality conditions, the optimal power allocation is calculated for each subchannel. In addition, then, an inter-cluster dynamic programming model is further developed to achieve the overall maximum energy efficiency. The theoretical analysis and simulations show that the proposed schemes achieve a significant energy efficiency gain compared with existing methods.

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“…The work of [23] exploits dual theory and the sub-gradient method to maximize the data rate under the NOMA-D2D background. In NOMA-based cognitive radio (CR) networks [24,25], researchers have put forward some effective resource optimization plans to maximize the achievable throughput in the network. The authors of [26] developed a monotonic optimization scheme to maximize the weighted system throughput.…”

Section: Introductionmentioning

confidence: 99%

Optimization Algorithms for Joint Power and Sub-Channel Allocation for NOMA-Based Maritime Communications

Zhou

2021

Entropy

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This paper investigates resource optimization schemes in a marine communication scenario based on non-orthogonal multiple access (NOMA). According to the offshore environment of the South China Sea, we first establish a Longley–Rice-based channel model. Then, the weighted achievable rate (WAR) is considered as the optimization objective to weigh the information rate and user fairness effectively. Our work introduces an improved joint power and user allocation scheme (RBPUA) based on a single resource block. Taking RBPUA as a basic module, we propose three joint multi-subchannel power and marine user allocation algorithms. The gradient descent algorithm (GRAD) is used as the reference standard for WAR optimization. The multi-choice knapsack algorithm combined with dynamic programming (MCKP-DP) obtains a WAR optimization result almost equal to that of GRAD. These two NOMA-based solutions are able to improve WAR performance by 7.47% compared with OMA. Due to the high computational complexity of the MCKP-DP, we further propose a DP-based fully polynomial-time approximation algorithm (DP-FPTA). The simulation results show that DP-FPTA can reduce the complexity by 84.3% while achieving an approximate optimized performance of 99.55%. This advantage of realizing the trade-off between performance optimization and complexity meets the requirements of practical low-latency systems.

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Joint User Pairing, Channel Assignment and Power Allocation in NOMA based CR Systems

Cited by 20 publications

References 33 publications

Multiobjective Optimization of Uplink NOMA-Enabled Vehicle-to-Infrastructure Communication

Multiobjective Optimization of Uplink NOMA-Enabled Vehicle-to-Infrastructure Communication

User Clustering and Power Allocation for Energy Efficiency Maximization in Downlink Non-Orthogonal Multiple Access Systems

Optimization Algorithms for Joint Power and Sub-Channel Allocation for NOMA-Based Maritime Communications

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