Performance Analysis And Optimization Of D2D Communication System In Cellular Network

With the explosive growth of data traffic and the popularity of mobile smart devices,mobile data traffic increases dramatically and the challenge for next-generation communication systems will be even more daunting.As one of the key technologies of the fifth generation of mobile communication,D2D(Device-to-Device)communication can effectively improve the system spectrum efficiency,expand the coverage of the base station,and improve the system capacity.With the development of content services,the demand for content sharing among users is becoming more and more common.The introduction of content caching mechanism in cellular network and D2 D hybrid network can effectively reduce content transmission redundancy and improve network capacity.Considering that the existing Wiener model can not accurately analyze the performance of cellular heterogeneous networks,this thesis introduces the spatial Poisson point process into the D2 D heterogeneous network,this work provides a solution for the performance analysis of the D2 D heterogeneous network.This thesis studies the incentive mechanism and selection algorithm in content sharing scenario,and deduces the performance indicators in the content sharing scenario with the spatial Poisson point process.Additionally,it analyzes the performance of D2 D communication in heterogeneous networks.The contents are as follows:(1)In D2 D content sharing scenario,user selection algorithm and incentive mechanism are proposed.The selection algorithm combines the remaining power and transmission rate of the user's device to select the best provider from the alternative content provider as D2 D transmitter.Incentive mechanism is to encourage content providers to actively participate in the content sharing.The base station rewards the providers,and the reward is determined by the transmission rate.Under the above mechanism,the optimal transmission power and the best reward price are deduced.The simulation results show that reward-based incentive mechanism not only increases the revenue of the user and base station,but also improves the transmission rate.(2)In the case of a caching-enabled D2 D network scenario,a new interference model is proposed and the system performance is analyzed.The new interference model is constructed by combining the spatial Poisson point process and stochastic geometry theory.When content caching user sends content to requesters through D2 D network,the interference received by the receiver comes from other D2 D transmitters that cache the typical content on the one hand,and from D2 D transmitters that do not cache the typical content on the other hand.Based on the proposed model,this thesis analyzes the cache hit probability,transmission success rate and cache service request density.The simulation results confirm the accuracy of the theoretical analysis and show that the success rate of the model proposed in this thesis is superior to the existing model.(3)In multi-cell networks and multiple potential D2D-pair network systems,a system model based on two exclusion zones is proposed and the network system is modeled and analyzed by spatial Poisson point process and stochastic geometry theory.The construction of two exclusion zones is to reduce the interference caused by the base station on the one hand and to reduce the interference caused by the other D2 D transmitters on the other hand.Under the above system model,the coverage probability of D2 D pair is derived by utilizing stochastic geometry.Meanwhile,the lower bound of area spectral efficiency in closed-form is derived under the condition that the distance is fixed between D2 D transmitter and D2 D receiver.Simulation results verify the theoretical analysis and demonstrate that the coverage probability of D2 D and the area spectral efficiency are improved.