Research On Resource Allocation Strategy Of C-V2X Vehicular Communication System

The number of civil cars shows a trend of sharp rise and the traffic situation becomes increasingly complex in the urban environments,which obviously lead to traffic congestion problem.The cellular vehicle-to-everything(C-V2X)lays a foundation for solving urban traffic problems in internet-of-vehicles(Io V).In the urban traffic congestion environments,vehicle-to-vehicle(V2V)communication with device-to-device(D2D)technology can utilize the spectrum resources of cellular users(CUE)to achieve V2 V direct communication.Although this scheme greatly reduces the burden of the base station,it also brings to co-frequency interference.In addition,the intersections of urban traffic congestion are more complicated,and congestion between vehicles and queuing for traffic lights are particularly prominent.Communication delay reduces the efficiency of information transmission between vehicles and effects on the passage time of vehicles at intersections.Therefore,how to implement efficient management of co-frequency interference and reduce communication delay is very important for alleviating road traffic congestion.The main contents of this dissertation are summarized as follows:First,the basic theory of C-V2 X vehicle communication system is summarized,including V2 X communication,D2 D communication technology and vehicle clustering algorithm.Second,the D2D-V2 V communication utilizes the spectrum resources of CUE to reduce the load of the base stations,and thus realize near-field V2 V communication,which improves the transmission rate of the system while causing co-frequency interference.To solve the issue,a dynamic power control scheme with channel inversion is proposed.In the scheme,channel inversion power control on V2 V users(VUE)is performed to compensate the truncation interruption caused by limited transmission power in the non-truncated area,where the co-frequency interference between cellular users and V2 V users is solved through dynamic power control.Furthermore,the optimal dual solution of objective function is obtained by Lagrange multiplier method and the optimal power allocation is carried out for cellular users and V2 V users by bisection method,which meets the rate requirements of all cellular users.Finally,the total transmission rate of V2 V users is maximized.Numerical analysis results are shown that,when the total outage probability of V2 V users is 0.866,the proposed scheme is promoted by 48%.Third,aiming at the problems of vehicle congestion and queuing at intersections in urban roads,the improved DEEC clustering algorithm is presented to select the vehicle node with higher energy of remaining node as the cluster head for improving the survival time of the cluster and utilize the relay vehicle to transmit information for reducing communication delay.At the same time,the improved Webster traffic light timing algorithm is used to conduct the corresponding signal phase scheduling and cycle timing,and thus reducing the delay time of vehicles.Finally,the improved Webster traffic light timing algorithm is verified by VISSIM traffic simulation modeling software that can reduce the delay time of vehicles and alleviate the traffic congestion in urban roads.Numerical simulation results show that the above scheme can reduce the communication delay and the vehicle delay time,and alleviate the urban traffic congestion.