Research On Wirless Resource Allocation For 5G V2X With Low Delay And High Reliability

With the development of intelligent cars and autonomous driving technology,Vehicle to Everything(V2X)technology has become one of the key technologies for intelligent transportation systems.State of the art V2X standardizations for the Fifth Generation(5G)of mobile communication technology are under fully consideration by domestic and foreign standardization organizations such as 3GPP(The Third Generation Partnerships Project),etc.Since the application of V2X is closely related to road and driving safety,this requires 5G V2X technology to achieve lower communication delay and higher communication reliability.The‘pedestrian-vehicle-road-cloud’collaborative interaction has become an effective 5G vehicular network deployment solution for a reduction of end-to-end transmission delay by combining 5G V2X technology with Mobile Edge Computing technology(MEC).In addition,based on the characteristics of 5G V2X communication services,key technologies related the wireless resource allocation need to be further improved for an enhancement of the reliability of 5G V2X communication.Therefore,given the 3GPP standardization requirements,this thesis conducts research on wireless resource allocation for 5G V2X technology from the perspective of latency reduction and reliability improvement.It mainly studies the following three aspects.Considering the high delay and low resource utilization under the condition of limited wireless and computing resources in 5G V2X,a joint optimization scheme of wireless resources and MEC computing resources is proposed to reduce the global delay in the vehicle edge computing network.Firstly,the proposed scheme applies the graph theory-based interference cancellation algorithm to allocate the wireless resources for the user terminal in the network to reduce the communication link interference caused by the resource block(RB)multiplexing.Then,based on the results of the resource allocation,the optimization goal is transformed into a convex function and the Lagrangian multiplier method is used to obtain the optimal solution of MEC computing allocation and offloading ratio in the offloading scheme.Finally,according to the proposed scheme,the base station allocates wireless resources and MEC computing resources to user terminals in the vehicle edge computing network,in order to minimize the global delay and improve the resource utilization.Simulation results demonstrate that the proposed algorithm achieve a reduction of global network delay by 42.9%,52.4%and 53.7%compared with the traditional scheme.Considering the sidelink bandwidth part(SL-BWP)configuration of the transmitting and receiving devices cannot coordinatly communicate,yet the reliability cannot meet the requirements of 5G V2X,a SL-BWP configuration and coordination scheme is proposed.The proposed scheme includes three processes:SL-BWP configuration,SL-BWP activation and SL-BWP coordination.User terminal firstly obtains SL-BWP configuration information through SL-BWP configuration.Then,base station activates SL-BWP based on communication requirements reported by user terminals.Finally,user terminals with different SL-BWP configurations establish reliable sidelink communications through the SL-BWP coordination process.Simulation results show that the proposed scheme improves the flexibility of 5G V2X wireless resource configuration while further ensuring the reliability of sidelink communication.In order to reduce the delay and improve the reliability of 5G V2X a step further,this thesis assesses the difficulty for user terminals to meet the channel busy ratio(CBR)measurement requirement in the in-device coexsistence scenario.Firstly,based on the characteristics of the 5G V2X traffic model,a CBR measurement with adjustable measurement window is proposed to reduce the measurement delay of the channel busy ratio while ensuring the measurement accuracy.Then,a CBR measurement scheme for user terminals under multiple radio access technology(RAT)in-device coexsistence scenario is proposed.Finally,user terminals report the measurement results to base station for wireless resource parameter adjustment indications.Analysis shows that the proposed channel busy measurement scheme combined with 5G V2X traffic model improves the stability of the measurement while reducing the measurement delay,which ensures the service quality of the sidelink communication.