Research On Cluster-based Resource Allocation Scheme For C-V2X

The V2X(Vehicle-to-Everything)communication is a critical component for future intelligent transportation system.By supporting vehicles to exchange basic safety message(BSM),sensor information,vehicle trajectory information etc.,V2X communication can improve transportation safety and efficiency and promote the development of automatic driving.The resource selection mode 4 in C-V2X(Cellular-V2X)supports vehicles’direct communication,where vehicles autonomously select radio resources based on a sensing-based semi-persistent scheduling(SPS)scheme.However,some researches show that this SPS scheme incurs low transmission reliability due to resource contention especially when the transmissions are aperiodic.Therefore,to address this issue,the distributed resource selection scheme is studied and a cluster-based resource allocation scheme is proposed to enhance the reliability of periodic and aperiodic transmissions.The main work and research contents are as follows.First of all,a cluster-based resource allocation scheme is proposed for C-V2X direct communication.The resources are divided into orthogonal resource sets.Vehicles select resource sets in the unit of cluster.Vehicles form into clusters based on energy measurement.Cluster heads schedule resources for their cluster members.The energy measurement method on each resource set is proposed first to improve the efficiency of resource reuse.Cluster heads select proper resource sets based on energy measurement result on each resource set.Meanwhile,an adaptive resource set reuse threshold determination method is proposed to reduce the interference between clusters,supporting the performance requirement in different vehicle density scenarios.Simulation results show that,compared with C-V2X mode 4,the proposed scheme improve the packet delivery ratio up to 10%in periodic traffic scenario and 20%in aperiodic traffic scenario.Secondly,the network throughput analysis model of mode 4 is constructed,and on this basis,the throughput of the proposed scheme is analyzed theoretically.The reason for transmission failure in each resource selection scheme is analyzed respectively.With considering the resource selection collision probability and vehicles’interference probability,the packet delivery ratio and throughput is theoretically derived in periodic traffic scenario and aperiodic traffic scenario.The impact of vehicle density and key parameters on system performance is analyzed through numerical simulation,which provides theoretical guidance and technical support for practical applications.