Research On Resource Scheduling Algorithm Of V2X Based On NOMA

LTE-V2X(Long-Term Evolution Vehicular to X)realizes the information interaction between vehicles and vehicles,vehicles and pedestrians,vehicles and other infrastructure through LTE communication technology,thus improving road safety.The reliability and effectiveness of communication links providing information interaction is the premise of ensuring road safety.Therefore,it is of great significance to study the related technologies of vehicle-to-vehicle communication.This paper mainly focuses on resource allocation in the process of vehicle-to-vehicle communication.At present,there are two resource allocation modes defined in the LTE-V2 V standard: centralized(mode 3)and distributed(mode 4).Different allocation modes adopt different resource allocation algorithms to reduce the probability of VUE resource collision,improve the success rate of data packet transmission and make V2 V communication more reliable.This paper studies two different resource allocation patterns based on the two scenarios of expressway and city block given in the3 GPP protocol.When VUE is out of the coverage area of the base station,it adopts the autonomous resource selection mode of mode 4.This paper introduces the basic principles of three resource selection algorithms in this mode,including random resource selection algorithm,resource selection algorithm based on Sensing and resource selection algorithm based on SA-decoding,and their performances are simulated and analyzed.The results show that the resource selection algorithm based on Sensing and SA-decoding can effectively improve the packet reception rate compared with the random selection algorithm.However,because these three algorithms are all VUE randomly selecting resources from their corresponding resource pools,which leads to a high probability of resource collision,thus this paper proposes a SA-decoding resource allocation algorithm based on probability selection.Simulation results show that the improved algorithm can effectively reduce the probability of resource collision,thus improving the data packet reception rate of the system.When VUE is in the coverage area of the base station,the resource scheduling mode of mode 3 is generally adopted.Mode 3 uses base stations for scheduling,so it can effectively solve the problem of resource shortage and resource collision caused by high vehicle density.Based on the analysis of the existing random resource allocation algorithm in mode 3,the performance of this algorithm is simulated and analyzed.The results show that the algorithm has good packet reception rate when resources are sufficient,but it is easy to cause packet blocking when resources are insufficient.Therefore,this paper proposes a V2 V resource allocation algorithm based on NOMA technology.The VUEs are grouped according to the distance between users,and the base station allocates the same resource block for the VUEs in the same group.Simulation results show that compared with the random scheduling algorithm based on mode 3,the resource allocation scheme based on NOMA technology has higher packet reception rate and more stable system reliability.