scholarly journals Cooperative Communications Combination Diversity Techniques And Optimal Power Allocation Expression

2015 ◽  
Vol 3 (4) ◽  
pp. 1-11
Author(s):  
Ahmed Hassan Mohammed Hassan ◽  
Ahmed M.Alhassan
Keyword(s):  
Power Allocation ◽  
Cooperative Communications ◽  
Optimal Power Allocation ◽  
Diversity Techniques ◽  
Optimal Power

Optimal power allocation for NOMA-enabled D2D communication with imperfect SIC decoding

2021 ◽  
Vol 46 ◽  
pp. 101296
Author(s):  
Shanshan Yu ◽  
Wali Ullah Khan ◽  
Xiaoqing Zhang ◽  
Ju Liu
Keyword(s):  
Power Allocation ◽  
D2d Communication ◽  
Optimal Power Allocation ◽  
Optimal Power

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

2021 ◽  
Vol 11 (2) ◽  
pp. 716
Author(s):  
Ruibiao Chen ◽  
Fangxing Shu ◽  
Kai Lei ◽  
Jianping Wang ◽  
Liangjie Zhang
Keyword(s):  
Energy Efficiency ◽  
Power Allocation ◽  
Multiple Access ◽  
Spectrum Efficiency ◽  
Lagrangian Multiplier ◽  
Efficiency Gain ◽  
Optimal Power Allocation ◽  
Optimal Power ◽  
User Clustering ◽  
Cluster Dynamic

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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