Research On Energy Efficiency In Wireless Powered Heterogeneous Networks

With the rapid development of mobile Internet,there are higher demands for data speed,which puts forward great requirement for energy efficiency(EE)in mobile communication networks.Recently,the novel deployments of het-erogeneous network(HetNet),Multiple-Input and Multiple-Output(MIMO)technology and Millimeter Wave(mm Wave)have enhanced the performance of wireless communication networks enormously.However,denser deployments and new technologies equipped in systems also lead to severe power consump-tion.In the attempt to reduce energy waste of networks,energy harvesting(EH)technology is considered to be applied in the wireless powered communication network(WPCN),where EH base stations(BS)can harvest energy from the radio frequency(RF)signal generated during the process of information trans-missions.A tractable mathematical model based on stochastic geometry(SG)is established,aiming to analyze grid power supply probability(PSP),through-put and EE of WPCN MIMO networks and mm Wave HetNets,respectively.Closed-form expressions of above performance metrics are derived by intro-ducing dummy random variables and are validated by using simulation results,which bring valuable insights of networks.The innovations and contributions of thesis can be summarized as follows:1)The results of grid PSP,throughput and EE are obtained in WPCN MIMO HetNets.Some closed-form expressions are derived according to Camp-bell's theorem and probability generating functional(PGFL)under the condi-tion of Poisson Point Processes(PPP)deployments of BSs and users.Results show that the proposed networks outperform the traditional networks in per-spective of EE.2)On the basis of WPCN MIMO HetNets,energy beamforming(EB)is introduced to the networks.Some non-EH BSs adopt maximum ratio trans-mission(MRT)strategy to participate in beamforming and then they harvest additional energy from the process.The thesis analyzes and proves that the in-troduction of EB nodes can effectively reduce the power consumption of the system and improve throughput and EE performance significantly.3)A hybrid HetNet,with mm Wave small cells for higher data rate and conventional macro BSs in sub-6 GHz frequency band to ensure wide coverage,is considered.In particular,high gain directional antennas are configured at the small BSs to avoid near path loss from mm Wave.Based on SG tools,the results show that the proposed hybrid EH mm Wave HetNets outperform the traditional networks in terms of network EE,especially under the dense BSs configuration,which suggests a bright prospect of future wireless network deployments.