Research On Wireless Resource Reservation Schemes Of Internet Of Vehicles

With the explosive growth of the number of vehicles,all countries have social problems such as frequent traffic accidents and traffic jams.It poses great challenges to the safety and efficiency of the current transportation system.As a part of the intelligent transportation system,Internet of Vehicles(Io V)play an active role in reducing traffic accidents,improving traffic congestion and providing assisted driving.It can timely provide important road traffic information,surrounding vehicle information and entertainment service information to improving the user’s service experience.V2 X is a communication channel for Io V.3GPP is standardizing on V2 X,and C-V2 X based on mobile cellular networks is the focus of 3GPP research.At present,3GPP recommends SB-SPS for vehicle autonomous resource selection in the standardization work.In SB-SPS,each vehicle determines the set of resource that may be idle by sensing the channel resource,and randomly selects the resource in the set as the communication channel of the vehicle.In the SB-SPS,there are problems of resource misjudgment and inefficient utilization of the idle resource in its resource awareness process,and in the resource selection process,due to the limited knowledge of the vehicle on the entire vehicle network,compared with base station based centralized resource reservation scheme,it exists a larger resource conflict.The thesis focuses on the above problems,the main research work and the main results obtained are as follows:Firstly,it outlines the concept of Io V,and focuses on the C-V2 X communication scenario,communication application requirements,time-frequency resource structure,and resource pool division framework.It summarizs the 4 working modes of LTE-V2 X and 2 working modes of NR V2 X in resource reservation scheme.It summarizs the 3 kinds of vehicle autonomous resource selection schemes defined by 3GPP in the resource reservation scheme,and focuses on analyzing the SB-SPS.Secondly,for the problems of SB-SPS that easily misjudge idle resource and inefficient utilization of the idle resource under SCI cannot correctly decode,this paper proposes the method of judging the idle resource based on resource occupation threshold and occupation period.The main innovations are as follows: First,we propose the method of judging the idle resource based on resource occupation threshold.when SB-SPS performs resource screening,the average S-RSSI calculation is not consider the actual transmission period of the vehicle.As it is easy to judge a busy resource block with long cycle and short distance as a idle resource block,then leads to misjudgment.So this paper introduces a resource occupation threshold to make the average S-RSSI calculation is more accurate.Second,we propose the method of judging the idle resource based on resource occupation period.Combining with the method mentioned above,we predict the period for which the vehicle uses the resource,then the candidate resource is idle within the period interval,and the resource can be allocated to vehicles that meet the requirement period,this method improves the utilization rate and reduces collision.In the aspect of simulation,the performance of the above scheme is verified through analysis and simulation.Finally,in order to solve the resource conflict in the resource selection process of SB-SPS,this paper proposes the conflict resolution scheme based on third-party message and resource alternation using.The main innovations are as follows: First,we propose the conflict resolution scheme based on third-party message.In a wireless environment,vehicles cannot transmit and receive at the same time.When two vehicles select the same resource block for data transmission,conflicts cannot be found.If there is a third-party vehicle,the third-party vehicle can find the conflict.Vehicles that have found conflicts can inform the parties to the conflict by adding conflict messages,and the conflicting parties reselect resources to achieve conflict resolution.Second,we propose the conflict resolution scheme based on resource alternation using.Without the assistance of the third-party vehicle,the conflict vehicle reduce the conflict by itself.The conflict vehicle can be assigned two time-frequency resources.The conflict vehicle uses them alternately.Although the conflict cannot be completely avoided,it can reduce the continuity conflicts,then reduce the probability of conflict.In the aspect of simulation,the performance of the above scheme is verified through analysis and simulation.