Research On Instantly Decodable Network Coding Transmission Scheme Based On Cooperative Data Exchange Of Internet Of Vehicles

Most important applications in the Internet of Vehicles require efficient data exchange,and Vehicle to Vehicle(V2V)communication has lower latency compared to Vehicle to Infrastructure(V2I)communication.V2 V communication is becoming a research hotspot in the field of information transmission in the Internet of Vehicles.As a network coding technology,Instantly Decodable Network Coding(IDNC)has been proven to effectively reduce network decoding delay.Therefore,this thesis considers using IDNC technology to reduce the delay of V2 V communication,which can provide theoretical and technical support for cooperative data exchange in the Internet of Vehicles.Limited by the transmission distance of the V2 V communication interface,this thesis studies two practical application scenarios based on the number and distribution density of vehicles: in busy urban sections,the vehicle distribution density is very high,and a vehicle can usually communicate with dozens or even hundreds of nearby vehicles in a single hop without intermediaries;However,in open rural areas,the distribution of vehicles is relatively sparse,and there is a lack of adjacent vehicles,which can only generate sporadic communication connections.This thesis abstract these two scenarios into fully connected and partially connected network topologies for research.Our main work and innovations include:(1)Considering the individual requirements of each vehicle for packets,the original packets are divided into primary and secondary packets according to the demand type of vehicles.Considering that the secondary packets received at the present may have the ability to provide instant decoding for the coded packets received in the future,the vehicle receive secondary packets while having the spare power to receive the primary packets;(2)In fully connected V2 V networks,a two-layer Local IDNC graph is proposed to represent the encoding opportunities between data packets based on the derived decoding delay expression,and the problem of minimizing decoding delay is transformed into the problem of finding the maximum weight clique in the graph.(3)In partially connected V2 V networks,the transmission scheme needs to consider both the selection of the set of sending vehicles and the selection of the set of encoded packets.Based on the derived expression of decoding delay and completion time,a two-layer conflict graph is proposed to represent all transmission conflicts and encoding conflicts,and the problem of minimizing decoding delay is transformed into the problem of finding the maximum weight independent set in the conflict graph.(4)Finding the maximum weight clique and the maximum weight independent set is an NP-hard problem.A weight setting rule is proposed according to the expression of decoding delay or completion time,and the greedy algorithm is used to convert the problem of finding the maximum weight clique or the maximum weight independent set into the proposed maximum weight vertex search problem.The simulation results show that the proposed scheme can achieve better decoding delay and completion time performance in both fully connected and partially connected networks.