Research On Energy Harvesting-Based D2D Multicast Cooperative Communication

Energy Harvesting(EH)-based Device-to-Device(D2D)Communication underlaying Cellular Network(EH-DCCN)combines the advantages of high energy and spectrum efficiency,lower transmission delay,green communication,which is one of the important terminal technologies of the next generation cellular network.However,the EH-D2 D communication is at risk of interruption because the available energy of EH-D2 D devices has strong randomness and intermittency.To handle this,the researchers do their utmost to accelerate the efficient Energy Management Methods(EMMs)and new controllable energy resource technologies(e.g.,Wireless Power Transfer(WPT))which are expected to efficiently replenish and use energy from the perspective of energy "throttling" and "open source" respectively.Nevertheless,D2 D Multicast(D2MD)communication can further improve Energy Efficiency(EE)from content sharing but is rarely mentioned in the research works of EMMs and WPT.As a result,in the process of implementing EH-DCCN,the current research works still have some problems,such as low content transmission coverage,low energy efficiency and low communication stabilityness.This dissertation addresses the bottleneck of unreliable available energy by combining the advantages of D2 MD mode,EMMs,WPT energy controllability.The main research contents of this dissertation are as follows:(1)Aiming at the problem that it is difficult to realize the optimal resource allocation due to the complex structure and heterogeneous node characteristics of EH-D2 MD,this dissertation constructs the available energy,physical distance and content request similarity of EH-D2 MD nodes as a two-layer network architecture.Based on the two-layer architecture,this dissertation investigates the joint cluster formation model and the convex approximation algorithm which can solve the grouping,CH selection and power control simultaneously.This dissertation firstly establishes the cluster formation model of EH-D2 MD network as a two-layered structure.And then,the Energy Efficiency(EE)maximization problem of D2 MD is establised.Thirdly,to acquire the joint cluster formation solution,a two-step Convex Approximation Algorithm(2-CDA)converts the above non-convex problem into a convex one which can obtain a tight approximate lower bound of original problem.Finally,the performance and complexity of 2-CDA are validated in the simulated scenarios.Moreover,2-CDA can help to discuss the network characteristics which can provide a reference for the energy efficiency conversion of hardware design or the power control of WPT.(2)To handle the transmission contradiction of single CH between the demand of energy consumption of multicast transmission and the fluctuation of energy supply,this dissertation proposes two multicast cooperative transmission strategies from content delivery and energy ultilization.The cooperative transmission strategies can guarantee transmission stability of EH-D2 MD with the aim of improving the multicast transmission rate,and can provide a more substantial theoretical basis for the implementation and deployment of EH-D2 MD.This dissertation firstly proposes a multi-cluster energy cooperative multicast transmission strategy by establishing a transmission rate maximization problem of D2 MD,which can solve the spectrum assignment,time planning between EH and data transmission and power control.After that,a three-step Convex Approximation Algorithm(3-CDA)is proposed to convert the non-convex form of original problem into convex.The theoretical proof and simulation analysis show that the 3-CDA can obtain the tight lower bound of the original rate maximization problem.The multi-cluster energy cooperative multicast transmission strategy cannot address the energy contradiction problem thoroughly because the energy conversion efficiency is not broken through and the WPT process is limited by the wireless channel fading and the transmission power control.Thus,this dissertation designs a multi-cluster head content cooperative multicast transmission strategy.With the same transmission rate maximization objective,the content cooperative transmission strategy jointly solves the spectrum assignment,time planning between EH and data transmission and power control.Simulations show the effectiveness of 3-CDA when it solves the content cooperative transmission rate maximization problem.The proposed two cooperative transmission strategies are both jointly designed and solved from the perspective of the cooperative patterns and resources allocation.The simulation results show that the multicast transmission stability is enhance by promoting the transmission rate of D2 MD.In the end,the performances of two cooperative strategies along with the increase of cluster members and member distribution radius are discussed,which can give the adaptability analysis of the strategies in EH-D2 MD.