Research On Energy Efficient Power Allocation Technology For Mmwave System Based On Non-orthogonal Multiple Access

Based on the novel idea of “green communication”,5G will pursue higher energy efficiency(EE)and lower power consumption.As the main candidate for the multiple-access protocol in 5G,non-orthogonal multiple access(NOMA)allows multi-user to communicate based on same resource block,which can evidently increase the EE of systems.In addition,millimeter-wave(mmWave)communication has been considered as one of the key technologies in 5G,because it can utilize a great deal of spare spectrum to improve the quality of communications.Therefore,in this thesis,the two technologies are merged,and the EE power allocation of millimeter-wave communications with NOMA(mmWave-NOMA)is studied,which can improve the EE performance of mobile communications and lay the foundations for the realization of “green communication” in 5G.The main work of the thesis is as follows:1.The energy efficient power allocation and beamforming of the downlink in mmWave-NOMA systems are investigated.According to the feature of mmWave channel,the joint EE optimization problem is decomposed into some sub-problems.The optimization of the power allocation and the design of beamforming vector are performed for these sub-problems,respectively.The corresponding scheme for power allocation is designed with the help of coordinate descent method,Karush-Kuhn-Tucher(KKT)condition and the theory of convex relaxation.Simulation results show that the proposed scheme can improve the EE performance effectively.2.The energy efficient power allocation and beamforming of the uplink in mmWave-NOMA systems are investigated.According to different decoding order,two types of joint EE optimization models are formulated.Based on convex optimization theory,two different EE optimization results can be obtained.Then the optimal decoding order can be decided.Simulation results verify the effectiveness of the proposed power allocation scheme.3.The energy efficient power allocation of the mmWave-NOMA systems with multi-user pairing is investigated.Multiple users are divided into different user-clusters by pairing scheme.Then the hybrid precoding is carried out to improve the quality of users' communications and reduce the interference from other user-clusters.Both the fully-connected hybrid precoding architecture and the sub-connected hybrid precoding architecture are considered,and the finite resolution analog beamforming(FRAB)is used to reduce the complexity of hybrid precoding.Simulation results show that the proposed power allocation scheme can attain pretty high EE performance with relatively low complexity.