Research On Improvement Of MAC Protocol Of Vehicle Power Line Communication Based On HomePlug AV

With the development of intelligent and electrified automobiles,the number of electronic devices in vehicles is increasing,which will lead to an increase in the number of power supply and communication harnesses in vehicles,and against the goal of lightweight and low energy consumption of vehicles.In order to solve this problem,vehicle power line communication(VPLC)technology has emerged,which uses the existing power supply harness in the car to communicate,thereby reducing the number of harnesses in the car.Media access control(MAC)protocol is one of the important factors to determine the communication performance of VPLC system,and there is currently no complete MAC protocol for the VPLC system.Therefore,based on the HomePlug AV protocol,this paper improves and designs the MAC protocol to meet the communication needs of VPLC systems.Firstly,this paper analyzes the MAC protocol of low-voltage power line,simulates the MAC protocol in the HomePlug AV protocol,and analyzes its communication performance,and proposes the problems in the current MAC protocol.Secondly,this paper classifies the signals in the vehicle,summarizes the communication requirements of different types of communication signals,and combines the problems existing in the current protocol to propose the design requirements of the MAC protocol for the VPLC system.Then,for the demand of random control signals,three different improvement schemes are proposed respectively,and their advantages and disadvantages are analyzed through simulation.On this basis,a priority-based MAC protocol is proposed to avoid channel conflicts and reduce overhead in this paper.The schedulability of the protocol is analyzed by modeling and simulation to verify its feasibility.Next,for the demand of periodic control signals,a time division multiple access(TDMA)mechanism is introduced,and the scheduling process is analyzed in combination with the packing model.According to the characteristics of the packing process,the packing rules are designed,and then a packing scheduling algorithm is proposed in this paper.The traditional scheduling algorithm and the proposed algorithm are compared and analyzed.The results show that the boxing scheduling algorithm proposed in this paper has higher time slot utilization and fewer slots.Finally,we analyze the structure of the power supply in the car and organize the network structure of the VPLC system.Combined with the characteristics of the improved scheme proposed in the previous paper,a hybrid MAC protocol is designed.The proposed MAC protocol is analyzed by MATLAB simulation platform.The results show that the hybrid MAC protocol has better communication performance and is suitable for VPLC system.