Research On Channel Access Of V2V In LTE-A Network

In view of the high speed,low latency and high reliability of LTE-A system,car networking based on LTE-A is a new research hotspot in recent years.LTE V2 V research is still in the initial stage and related standards of LTE V2 V are still being developed.In current times,the mainstream program of LTE V2 V research is to make minor changes based on LTE D2 D and the corresponding channel access problem of V2 V communication is an urgent problem to be solved.Channel access of V2 V communication is a process of competing and using communication resources,including centralized control pattern and distribute competing pattern.Channel access of centralized control pattern is the process to build link and access to communication resources under the control of eNB.Channel access of distribute competing pattern is the process that vehicles randomly access to channel to communicate by themselves.Thesis researches channel access of the above two ways for single-cell scenario relied on the project of “5G V2 V technology research”.In the centralized way,thesis aimed at both intensive scenario and multicast scenario.Specific work has the following aspects.Firstly,thesis analyzed the problem of channel access of LTE V2 V and the influence of vehicle-intensive scene on channel access and confirmed the expansion mechanism of LTE preamble.On this basis,thesis designed a V2 V Channel Access Algorithm in Vehicle Intensive Scenario.Then thesis analyzed and simulated the algorithm deeply.The simulation results show that the proposed algorithm can reduce the collision rate and increase the success rate of channel access while using less resources in case of the dense scene.Secondly,based on the analysis of the CAM message in vehicle networking,thesis designed a fast V2 V link building algorithm with prejudge mechanism based on CAM.This mechanism takes the channel quality of the V2 V link,the resource usage,the degree of interest and fitness between the vehicles into account,and then screens the vehicles based on these conditions in order to avoid meaningless link building.The simulation results show that the algorithm can improve the effective link establishment rate and success rate of link building.Thirdly,thesis proposed a resource allocation algorithm aiming at V2 V multicastcommunication,which takes the interference between the communication links,the use of the system resources and the carried capacity of link into account in order to prioritize the limited communication resources to more capacity-carrying links,thus maximizing system throughput.The simulation results show that the algorithm can maximize the system throughput and reduce the resource conflict rate.Fourthly,thesis analyzed the shortcomings of the existing distributed channel access algorithm and then designed a LTE V2 V random channel access algorithm with collision avoidance mechanism.Simulation analysis shows that the proposed algorithm can reduce collision rate and increase the access efficiency.