Vehicle Information Sensing And Interacting Method For Internet Of Vehicles

The Internet of Vehicles is a service system that combines information sensing,processing and interacting.Through wireless communication,information exchange between vehicles,roads,pedestrians and the Internet can comprehensively sense and share various dynamic and static information of traffic participants and traffic environment.In this paper,a number of key issues of in-vehicle information sensing and interacting oriented for the Internet of Vehicles are deeply studied,the main work is as follows:(1)Based on the in-depth analysis of vehicle information sensing and interacting demand in the environment of the Internet of Vehicles,this paper presents a vehicle sensing and interacting system architecture based on the system architecture of the Internet of Vehicles.The system uses GPS as the means of space locating,mobile data network(4G LTE)as the means of data transmission,and vehicle sensing and interacting terminal as the means of core carrier,to realize functions,such as vehicle state information sensing,state analysis and management,early warning/alarm.The composition of the system structure,workflow,sensing node layout are described in detail.(2)In order to enhance the real-time performance of the TinyOS scheduling algorithm,a priority-based RTQ-TOSQ scheduling algorithm is proposed.First,The task is divided into real-time tasks and common tasks.Time attribute description information is added accordingly.Second,based on the compatibility to the original TinyOS kernel dispatching API and semantics,real-time guarantee for task execution is achieved through two independent task queues(RTQ and TOSQ),and Non-Preemptive Earliest Deadline First(NPEDF)algorithm,and task timeout detection meachanism.Experimental results show that the new scheduling algorithm can both effectively reduce the task loss rate and increase the real-time response for real-time tasks,without generating too much computing,storage and energy consumption.(3)In order to optimize the throughput and access latency of vehicle sensing and interacting systems,some improvements have been made to the MAC layer protocol.First,A GDCF backoff algorithm with priority is designed and implemented.The saturation throughput is increased by reducing the contention window smoothly,so that the collision probability and the number of retransmissions are decreased Second,the RTS/CTS mechanism is eliminated because of the small communication packet size in the system.System throughput is enhaced and the access latency is reducede.Third,the sleep mechanism is introduced into the sensing nodes.Energy efficiency of sensing nodes are made better.Because the nodes' duty ratio of working time is effectively reduced.Experimental results show that the GDCF algorithm can keep a low packet loss rate;after removing the RTS/CTS mode,the network packet loss rate is less than 0.5%;after the sleep mechanism is introduced,the energy saving rate can reach 95% in one cycle.(4)In order to improve the serial data transmission efficiency in the physical layer,a wireless transmission mechanism based on parallel buffer read and write is designed and implemented.The data is transmitted while it is being written to the buffer.The radio chip sent the data frame header immediately after being waken up from the sleep mode.At the same time the microcontroller initializes the RF chip interface bus and fills the payload of the data frame to the RF chip buffer.The experimental results show that the serial data wireless transmission mechanism based on buffer parallel read and write reduces the transmission delay by 50%,which can meet the demand of improving data transmission efficiency.(5)Based on the system architecture we designed,hardware selection scheme,hardware parameters,and hardware/software design scheme are determined,according to which an in-vehicle sensing and interacting test platform is deigned to test the system stability,response speed,and the performance of the three subsystems.Experiment results show that the system can stabely working for a long time,network performance and transmission speed of the subsystems can meet application and design requirements.This paper proposes a vehicle sensing and interacting system architecture based on the research of some key technologies of the Internet of Vehicles information sensing and interactive system.It solves some problems in vehicle information sensing and interacting,through optimize in-vehicle sensing node real-time task scheduling algorithm,MAC layer protocol and physical layer transmission time sequence.The results of this research have important reference value for the realization of vehicle information sensing and interacting in the Internet of Vehicles.