Delay Optimization Of Routing Layer In D2D-Based Vehicular Networking

Recently,the rapid increase in the number of vehicles has intensified the problems of traffic accidents and congestion,which led to the increasing attention of the vehicular ad-hoc network(VANET).VANET is based on the IEEE 802.11 p protocol traditionally,which generates a large delay.Since many vehicular networking applications in the future have strict requirements on delay,device-to-device(D2D)communication is introduced into VANET due to its advantages of wide communication range,high transmission rate and good mobility.This thesis focuses on the resource allocation and interference management of D2 D in the Internet of Vehicles.Firstly,an algorithm for dynamically allocating resources with minimum delay is proposed,which is based on a hybrid system with IEEE 802.11 p and D2 D communication coexistence and an underlying spectrum sharing scheme.The link distance of the D2 D communication,the interference of the D2 D user to the cellular user,and the interference between the D2 D users are constrained within a certain threshold while considering the interference of the neighboring cell users and the greedy algorithms is used to reduce complexity.The simulation results show that the resource allocation by this method achieves the effect of improving spectrum utilization and reducing delay.Secondly,a D2D-based vehicle relay algorithm is proposed.This algorithm compensates for the limitation of the transmission via road side unit based on V2V/V2I(Vehicle-to-Vehicle /Vehicle-to-Infrastructure).The hybrid system model firstly clusters vehicles based on motion consistency to maintain a stable and long-lasting connection.The cluster head vehicles can be connected via V2 I and V2 V links.Based on the signal to interference plus noise ratio and the minimum capacity constraint,the optimal transmission path is selected by predicting the delay of each cellular link and D2 D link.The simulation results show that the relay algorithm effectively reduces the end-to-end transmission delay compared with other methods.