This paper investigates a new strategy for radio resource allocation applying a non-orthogonal multiple access (NOMA) scheme. It calls for the cohabitation of users in the power domain at the transmitter side and for successive interference canceller (SIC) at the receiver side. Taking into account multi-user scheduling, subband assignment and transmit power allocation, a hybrid NOMA scheme is introduced. Adaptive switching to orthogonal signaling (OS) is performed whenever the non-orthogonal cohabitation in the power domain does not improve the achieved data rate per subband. In addition, a new power allocation technique based on waterfilling is introduced to improve the total achieved system throughput. We show that the proposed strategy for resource allocation improves both the spectral efficiency and the cell-edge user throughput. It also proves to be robust in the case of communications in crowded areas.Index terms -non-orthogonal multiple access, power domain multiplexing, waterfilling, resource allocation.
In this letter, a low-complexity waterfilling-based Power Allocation (PA) technique, incorporated within the Proportional Fairness (PF) scheduler, is proposed and applied to a Non-Orthogonal Multiple Access (NOMA) scheme in a cellular downlink system. The aim of the proposed joint PA and scheduling scheme is to maximize the achieved average throughput through a quasi-optimal repartition of the transmit power among subbands, while guaranteeing a high level of fairness in resource allocation. Extensive simulation results show that the proposed technique enhances both system capacity and user fairness, when compared to either orthogonal signaling (OS) or NOMA with static PA.
This paper investigates several new strategies for the allocation of radio resources (bandwidth and transmission power) using a non-orthogonal multiple access (NOMA) scheme with successive interference cancellation (SIC) in a cellular downlink system. In non-orthogonal access with SIC, the same subband is allocated to multiple users, which requires elaborate multiuser scheduling and subband assignment techniques, compared to orthogonal multiplexing. While taking into account various design issues, we propose and compare several optimum and suboptimum power allocation schemes. These are jointly implemented with multiple user scheduling strategies. Besides, a minimization of the total amount of used bandwidth is targeted. Also, to increase the total achieved system throughput, a hybrid orthogonal-non orthogonal scheme is introduced. This hybrid scheme enables a dynamic switching to orthogonal signaling whenever the non-orthogonal cohabitation in the power domain does not improve the achieved data rate per subband. Extensive simulation results show that the proposed strategies for resource allocation can improve both the spectral efficiency and the cell-edge user throughput, especially when compared to previous schemes employing either orthogonal signaling or NOMA with static
Non-Orthogonal Multiple Access (NOMA) schemes superpose multiple users in the power domain. It is commonly assumed that the achieved throughput in a downlink NOMA system increases with the channel gain difference between paired users. This paper investigates the accuracy of this claim when different intra-subband power allocation techniques are studied. Moreover, the Proportional Fairness (PF) scheduler is used as a resource allocation mechanism to highlight the importance of the choice of user pairing and of the intra-subband power allocation scheme. Results show that the achieved throughput does not always evolve in the same direction as the channel gain difference between paired users, owing to the choice of the intra-subband power allocation technique. In addition, it was found that the PF scheduler is not fully adapted to NOMA.
A weighted proportional fair (PF) scheduling method is proposed in the context of nonorthogonal multiple access (NOMA) with successive interference cancellation (SIC) at the receiver side. The new scheme introduces weights that adapt the classical PF metric to the NOMA scenario, improving performance indicators and enabling new services. The distinguishing value of the proposal resides in its ability to improve long-term fairness and total system throughput while achieving a high level of fairness in every scheduling slot. Finally, it is shown that the additional complexity caused by the weight calculation has only a limited impact on the overall scheduler complexity, while simulation results confirm the claimed improvements, making the proposal an appealing alternative for resource allocation in a cellular downlink system.
Abstract-In this paper, a novel resource allocation technique is proposed for a power-domain non-orthogonal multiple access scheme using successive interference cancellation in a downlink cellular system. It aims at providing a flexible balancing between throughput and fairness maximization and incorporates unequal power repartition among allocated subbands using waterfilling. Its main strength is the ability to achieve a high level of fairness in every scheduling slot, therefore improving the quality of experience for all users. Fairness is achieved by the introduction of a new efficient scheduling metric within the allocation process. Extensive simulation results show that the proposed metric enhances both long-term and short-term fairness, and improves system capacity, when compared to the conventional proportional fairness scheduler.
In this paper, a novel resource and power allocation technique is proposed for a power-domain non-orthogonal multiple access scheme using successive interference cancellation in a downlink cellular system. It aims at providing a flexible balancing between throughput and fairness maximization and incorporates unequal power repartition among allocated subbands using waterfilling. Its main strength is the ability to achieve a high level of fairness in every scheduling slot, therefore improving the quality of experience for all users. Simulation results show that the proposed metric enhances fairness and improves system capacity, when compared to the conventional proportional fairness scheduler. Index Terms-Power-domain non-orthogonal multiple access, user scheduling, power allocation, fairness.
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