Energy Efficiency Optimization For Machine Type Communications

With the rapid development of mobile communication technology,the un-precedented expansion of Information and Communications Technology(ICT)industry has resulted in excessive energy consumption.International Telecom-munication Union-Radio communications sector.(ITU-R)expects that the net-work energy efficiency could have a 100-fold increase in the blueprint for the Fifth Generation Mobile Communication(5G).Efficient schemes to achieve green 5G network are in urgent need.Massive Machine Type Communication(MTC)is one of the most typical scenarios in the 5G wireless networks.In this scenario,obj ects are equipped with sensors and m icroprocessors to collect information of surroundings,communicate with each other and execute smart applications.Applications of MTC span from environmental monitoring,smart agriculture to health care systems.It is characterized by small data packet,low power consumption,low cost and massive connections.In this context,this thesis studies the energy efficiency modeling and optimization for 5G MTC scenario.The main contributions are as follows.First of all,under the delay constraints,a cross-layer energy efficiency an-alytical model with two modes(transmission mode and idle mode)and a novel adaptive transmission strategy are proposed.This model allows the transceiver to use the channel with better coefficients and enter silent state when the channel suffers deep fading.The transceiver would choose transmission or idle mode based on the channel condition in order to save energy.Compared with the tra-ditional single mode,simulations show that the proposed transmission strategy could obtain energy efficiency gains up to 12%.Secondly,based on the formulated energy efficiency model,under end-to-end delay-outage constraints,this thesis investigates the effectiveness of the strategy and further optimizes the strategy to obtain the maximum energy effi-ciency over Nakagami-m block fading channels.Binary search algorithms are utilized to achieve a most energy-efficient scheme.Simulations demonstrate that the algorithm is reliable and analysis of the strategy is accurate.Finally,this thesis an alyzes en ergy efficiency in a relay transmission sys-tem.A cellular user,as a relay,collects data from Machine-Type Device(MTD)through Device-to-Device(D2D)links,supplements it with its own data and transmits all of them to the base station.Time slot division based on Time Divi-sion Multiple Access(TDMA)and relay access process based on permission re-quest provide an energy efficiency analysis method in this scenario.Simulation results prove the feasibility of the analysis method and indicate that adjusting resource allocation could contribute to increasing energy efficiency.