Optimum Power Allocation for Non-orthogonal Multiple Access (NOMA (original) (raw)
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Wireless Personal Communications, 2015
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
ELKHA, 2021
This research based on simulation to show impact of the power allocation on Non-Orthogonal Multiple Access (NOMA) using Successive Interference Cancellation (SIC). NOMA used superposition code (SC) on the transmitter and SIC on the receiver. NOMA has two categories power domain (PD) and code domain (CD). This research based on PD-NOMA simulated for downlink. The number of users who use the same recourse block are divided into two conditions: user with apply SIC and without SIC base on the value of channel gain from each user. Applying SC on the transmitter and SIC on the receiver will cancel of interference. Novelties of this research are the best performance of power allocation and user mobility based on parameter BER and SNR. Allocation of the power transmit based on value of channel gain every user, where user with value of channel gain is low will be allocated high power transmit, and otherwise. The best result performance of BER vs SNR used ratio power transmit 0.45 dB:0.55 dB,...
Performance of Non-Orthogonal Multiple Access (NOMA) with Successive Interference Cancellation (SIC)
3D SCEEER Conference, 2020
Non-Orthogonal Multiple Access (NOMA) has been promised for fifth generation (5G) cellular wireless network that can serve multiple users at same radio resources time, frequency, and code domains with different power levels. In this paper, we present a new simulation compression between a random location of multiple users for Non-Orthogonal Multiple Access (NOMA) and Orthogonal Multiple Access (OMA) that depend on Successive Interference Cancellation (SIC) and generalized the suggested joint user pairing for NOMA and beyond cellular networks. Cell throughput and Energy Efficiency (EE) are gained are developed for all active NOMA user in suggested model. Simulation results clarify the cell throughput for NOMA gained 7 Mpbs over OMA system in two different scenarios deployed users (3 and 4). We gain an attains Energy Efficiency (EE) among the weak power users and the stronger power users.
IEICE Transactions on Communications, 2015
This paper investigates the system-level throughput of non-orthogonal multiple access (NOMA) with a successive interference canceller (SIC) in the cellular downlink assuming proportional fair (PF)based radio resource (bandwidth and transmission power) allocation. The purpose of this study is to examine the possibility of applying NOMA with a SIC to the systems beyond the 4G cellular system. Both the mean and cell-edge user throughput are important in a real system. PF-based scheduling is known to achieve a good tradeoff between them by maximizing the product of the user throughput among users within a cell. In NOMA with a SIC, the scheduler allocates the same frequency to multiple users simultaneously, which necessitates multiuser scheduling. To achieve a better tradeoff between the mean and cell-edge user throughput, we propose and compare three power allocation strategies among users, which are jointly implemented with multiuser scheduling. Extensive simulation results show that NOMA with a SIC with a moderate number of non-orthogonally multiplexed users significantly enhances the system-level throughput performance compared to orthogonal multiple access (OMA), which is widely used in 3.9 and 4G mobile communication systems.
Analysis of Power Allocation for Non-Orthogonal Multiple Access
Journal of Physics: Conference Series, 2021
Most multiple access schemes provide orthogonal access to the users in time, frequency, code and space, this is not true for NOMA, where each user operates in the same band and at the same time where they are distinguished by their power levels. It uses superposition coding at the transmitter such that the successive interference cancellation (SIC) receiver can separate the users both in the uplink and in the downlink channels. The users in (NOMA) are classified based on power, while in Orthogonal Multiple Access (OMA) it is classified based on time, frequency, and code. The NOMA system contains a power-delay tradeoff and hence power efficiency becomes critical for Ultra-Reliable Low Latency Communication (URLLC), especially where a huge number of devices are battery-powered. Combining these considerations, we simulate Dynamic Power Allocation (DPA) for power domain non-orthogonal multiple access (PD-NOMA) with user mobility. For small and clumsy battery-powered IoT devices, power efficiency becomes critical. Further, flexibility is also important to communicate with diverse machine-type devices as well as human users while meeting a variety of quality of service (QoS) requirements. The performance of the DPA is compared with Static Power Allocation under user mobility.
A Computational Power Allocation Scheme for Fair NOMA Downlink System
2018
Representing the next generation wireless network, non-orthogonal multiple access (NOMA) has become crucial multiple accessing techniques in recent times. In this article, the core issue of NOMA system, allocating power to multiple users has been addressed. In NOMA, the increment in the power of one user increases the interference of other users because all the users utilize the same frequency band but distinguish by their power level. To cancel the signals of other users at reception, users must perform successive interference cancellation (SIC) by handling other users' signals as noise and finally decode its own signal. Incompetent power allocation could upturn the interference greatly, which decreases the data rate and user fairness, the result is degradation of the system capacity and unfair user data rate. Simulation results showed that power allocation of each user has a great impact on other users' data rate and total system capacity. In this article computational app...
Novel Resource Allocation Techniques for Downlink Non-Orthogonal Multiple Access Systems
Applied Sciences
Non-orthogonal multiple access (NOMA) plays an important role in achieving high capacity for fifth-generation (5G) networks. Efficient resource allocation is vital for NOMA system performance to maximize the sum rate and energy efficiency. In this context, this paper proposes optimal solutions for user pairing and power allocation to maximize the system sum rate and energy efficiency performance. We identify the power allocation problem as a nonconvex constrained problem for energy efficiency maximization. The closed-form solutions are derived using Karush–Kuhn–Tucker (KKT) conditions for maximizing the system sum rate and the Dinkelbach (DKL) algorithm for maximizing system energy efficiency. Moreover, the Hungarian (HNG) algorithm is utilized for pairing two users with different channel condition circumstances. The results show that with 20 users, the sum rate of the proposed NOMA with optimal power allocation using KKT conditions and HNG (NOMA-PKKT-HNG) is 6.7% higher than that o...
Energy-Efficient Joint User-RB Association and Power Allocation for Uplink Hybrid NOMA-OMA
IEEE Internet of Things Journal, 2019
In this paper, energy efficient resource allocation is considered for an uplink hybrid system, where non-orthogonal multiple access (NOMA) is integrated into orthogonal multiple access (OMA). To ensure the quality of service for the users, a minimum rate requirement is pre-defined for each user. We formulate an energy efficiency (EE) maximization problem by jointly optimizing the user clustering, channel assignment and power allocation. To address this hard problem, a many-toone bipartite graph is first constructed considering the users and resource blocks (RBs) as the two sets of nodes. Based on swap matching, a joint user-RB association and power allocation scheme is proposed, which converges within a limited number of iterations. Moreover, for the power allocation under a given user-RB association, we first derive the feasibility condition. If feasible, a low-complexity algorithm is proposed, which obtains optimal EE under any successive interference cancellation (SIC) order and an arbitrary number of users. In addition, for the special case of two users per cluster, analytical solutions are provided for the two SIC orders, respectively. These solutions shed light on how the power is allocated for each user to maximize the EE. Numerical results are presented, which show that the proposed joint user-RB association and power allocation algorithm outperforms other hybrid multiple access based and OMA-based schemes. Index Terms-Non-orthogonal multiple access (NOMA), energy efficiency (EE), power allocation (PA), uplink transmission. I. INTRODUCTION Non-orthogonal multiple access (NOMA) has been considered as a promising candidate for the fifth generation (5G) and beyond 5G cellular networks [2]-[7]. The key idea of NOMA is to serve multiple users simultaneously over the same radio resources. The introduced inter-user interference is mitigated by employing successive interference cancellation (SIC) at the receiver. Downlink NOMA has been extensively studied so far. Some works target sum rate maximization and show that higher spectral efficiency (SE) can be achieved by NOMA when compared with conventional orthogonal multiple
Efficient power allocation method for non orthogonal multiple access 5G systems
International Journal of Electrical and Computer Engineering (IJECE), 2020
One of the hot research topics for the upcoming 5G (fifth-generation) wireless communication networks is the non orthogonal multiple access (NOMA) systems, where it have attracted both industrial and academic fields to improve the existing spectral efficiency. In fact, the multiuser detection process for NOMA systems is largely affected by the power distribution of the received signals. In this paper, a new method has been proposed to control the transmit power among active users in one of the promising NOMA systems; the interleave division multiple access (IDMA) which has been adopted here for consideration. Unlike conventional methods, where tedious mathematical computations are required; a simple and direct method has been derived. The proposed method has been applied to IDMA system with different FEC codes. The obtained results show that the proposed method outperforms the conventional one as compared to optimal results.