Performance Analysis And Optimization Of D2D Heterogeneous Cellular Network Based On Queuing Theory

In recent years,with the continuous popularization and rapid development of smart mobile terminals,the explosive growth of mobile data has put forward new requirements on mobile networks.How to use limited spectrum resources to meet the communication requirements of mobile services as much as possible is one of the key issues that need to be solved urgently in future wireless communication networks.Existing studies have shown that the rational application of D2 D communication in cellular networks can achieve higher spectrum efficiency,energy efficiency and lower service delay.However,complex services and network environments have brought difficulties to resource allocation in D2 D cellular networks.Therefore,modeling and analyzing D2 D networks in dynamic environments and realizing resource optimization have become a research hotspot in the communication field.Based on stochastic geometry and queuing theory,this dissertation studies the performance analysis and resource optimization methods of D2 D heterogeneous cellular networks.Based on the stochastic geometry theory to model the dynamic interference of the network,we use the M/G/1queuing model to analyze the adaptive control mechanism of the transmission rate,and obtain the spatiotemporal service and transmission model of the D2 D cellular heterogeneous network.Considering priority business types,we established a queuing model with a dynamic priority jump strategy,and analyzed the network performance based on the birth and death process.On the basis of the established spatiotemporal business model,we conducted performance analysis and optimization for the D2 D cellular heterogeneous network with retransmission mechanism.In the D2D-assisted cache network,we proposed a push pre-storage mechanism to offload the base station load,and analyzed the load offload rate of the cache network.The specific research content and innovations of this thesis are as follows:(1)In view of the impact of dynamic interference on the transmission rate in the D2 D heterogeneous cellular network,the spatiotemporal service and transmission model of the D2 D heterogeneous cellular network is established based on queuing theory and stochastic geometry.Considering the arrival and departure of data packets in the user queue buffer,the queue status will cause the interference of the link to change.According to the probability that the received SINR falls into a certain range,an adaptive transmission rate control strategy is proposed to adapt to the communication Environmental changes.Modeling the location distribution of users as a Poisson point process based on stochastic geometry,we use channel inversion to control the uplink power of cellular users.We further use the M/G/1 queuing model to analyze the relationship between queue status and interference in the D2 D cellular heterogeneous network.According to the derivation of the complementary cumulative distribution function(CCDF)of the instantaneous SINR of cellular users,the discrete-time Markov chain is used to derive the state transition probability matrix and its steady-state distribution,and the expressions of performance parameters such as average queue length and average throughput are obtained.The simulation results show the correctness of the theoretical analysis.By comparing the average delay between the finite buffer and the infinite buffer model,it is proved that the finite buffer model proposed in this chapter is more accurate in practical applications.(2)Aiming at the priority data transmission scenario in the D2 D cellular heterogeneous network,a dynamic priority jump strategy is proposed,and the network performance is analyzed based on the birth and death process.Assuming that the service of the D2 D user has two priorities,a high and a low priority,the priority transmission opportunities of the two services are dynamically adjusted according to the delay requirements of the low priority service.This strategy effectively reduces the packet loss and system delay caused by the detention of low-priority queue services.By using the thin Poisson point process to establish a dynamic interference model for D2 D users with sending data,the complementary cumulative distribution function of the SINR of D2 D users is derived,which is regarded as the service probability of the queue.A two-dimensional Geo/G/1Markov chain is established,and the transition status of high and low priority queues is analyzed using the quasi birth and death process.The iterative method is used to calculate the steady-state probability distribution and obtain the expressions of performance parameters such as system throughput,delay and packet loss rate.The simulation results show the correctness of the theoretical analysis.By analyzing the average packet loss rate under the change of the user queue buffer size and the BS density,we point out that setting a proper user density can ensure a lower packet loss rate.(3)Aiming at the problem that data packets cannot be received correctly due to interference and poor channel environment in D2 D networks,a spatiotemporal model is established to analyze the retransmission mechanism of D2 D cellular heterogeneous networks.The model is based on queuing theory and stochastic geometry.The position of the D2 D user in the business backlog state is modeled as a Poisson point process.A feedback queuing model is established,in which the service probability of the queue leaving process is determined by the user’s received SINR.In order to analyze the queue state in the buffer,it is expressed as an embedded Markov chain,and its steady-state distribution and closed expressions of performance parameters such as average throughput and average delay are calculated by an iterative method.The simulation results show that the theoretical analysis of the model under different channel parameters and D2 D density is correct,and the retransmission strategy can effectively improve the packet loss performance of the system.(4)For the D2D-assisted mobile cache network,a push pre-storage mechanism is proposed to offload the base station load,and the load offload rate of the cache network is analyzed.In the cache network,the base station broadcasts the most popular files to users during off-peak hours.Under this pre-storage mechanism,the queuing model is used to analyze the user’s cache queue,and the transmission process of the requested file is analyzed.The base station and user locations are modeled as independent Poisson point processes.Assuming that the file requested by the user can be obtained through the three working methods of its own cache,D2 D sharing and base station,the queue status and uninstall strategy of the requested file are constructed as a two-dimensional Markov chain.By analyzing the status of the file queue in different working modes,the steady-state probability distribution is solved based on the quasi birth and death process,and the expression of key performance parameters is obtained.The simulation results show that the proposed cache strategy can effectively increase the offload probability of the base station and reduce the network load.