Design Of User Access Schemes For Low-latency Data Transmission In The Internet Of Vehicles And Research On Scheduling Algorithms

Internet of Vehicles is one of the key technologies to realize the future intelligent transportation system.With the continuous development of autopilot technology,the Internet of Vehicles puts higher demands on the delay of data transmission.At the same time,as one of the five major scenarios of 5G,the ultra-low latency and high reliability scenarios require that the air interface delay of data transmission be controlled within 1 ms.However,the traditional car network design scheme is mainly based on LTE D2 D technology,and the data transmission delay allowed is difficult to meet the delay requirement of the autopilot technology,and its main application scenarios are public place in cities such as commercial entertainment.For the design of car networking in high-speed scenes,the problem of low-latency data transmission of self-driving vehicle terminals in high-speed scenes needs to be solved urgently.In this paper,the delay,reliability and system throughput of car network data transmission in high-speed scene are studied.Firstly,three main influencing factors are analyzed,namely the closed-loop communication system using HARQ retransmission mechanism and the high-speed vehicle in the traditional LTE system.Fast handover of traveling cell and stability of user access at the edge of mobile network.This paper proposes a low-latency user access scheme for vehicle networking in high-speed scenarios.The scheme is mainly divided into four steps: first,a data transmission method combining a macro node and an access point(micro node),when the vehicle terminal requests resource scheduling for an access point group composed of multiple access points,According to the size of the requesting resource block,whether the scheduling is completed by the macro node or the access point group;secondly,the open-loop communication mode adopting the path diversity,since the high-speed moving scene has no complicated channel interference like the urban street,it can take more The access points automatically drive the vehicle for data transmission through path diversity,cancel data retransmission,and can meet low delay and high reliability data transmission performance.Third,the access point is composed of a fog node server,and the fog calculation technology has The local cache and powerful computing storage function can realize the distributed layout in the mobile network.Fourth,the macro node manages and controls the data resources in the access point.The experimental results show that the user access scheme greatly reduces the delay of data transmission while ensuring high data transmission reliability,but the system throughput is very low.In order to improve the reliability and system throughput of the above-mentioned vehicle network low-latency user access scheme data transmission,this paper proposes a pre-scheduling algorithm that can allocate cache resources autonomously by optimizing the traditional pre-scheduling(semi-static)algorithm.The algorithm includes two aspects: macro node and access point design: in a certain period,the macro node counts and calculates the buffer resources of one cycle of each access point through the fast sorting algorithm,and sends the next period of allocation to the access point.Cache resource instructions;each access point allocates a resource cache according to an instruction of the macro node to complete resource scheduling for the vehicle.Experimental results show that the algorithm improves data transmission reliability and system throughput.