Research On Resource Management Of LTE-based V2X Communication

With the rise of smart cars and autopilot technology, V2X (Vehicle to Everything) communication is treated as one of the most important development directions by many technology organizations. Currently,international standardization organizations, like 3 GPP, have begun to promote the LTE (Long Term Evolution) based V2X communication technology. Wireless resource management technology is an important aspect of the design of LTE based V2X communication system, and the combination of central scheduling and distributed communication is realized through the tight coupling between V2X communication and the cellular network. At the same time, V2X communication has stricter requirements on mobility, latency and reliability which brings great challenges to cell handover and V2X communication through Uu interface. Considering the resource management of LTE-based V2X communication, the main research points of this thesis are summarized as follows:Considering the urgent resource demand and the shortage of spectrum resource in V2V communication, the problem of resource block(RB) scheduling for maximizing the number of concurrent V2V transmissions instead of sum rate is considered in this thesis, allowing multiple vehicles to access to one RB. Firstly, the reliability requirement is transformed into a constraint of a matrix spectral radius to limit the accumulated interference. Secondly, utilizing spectral radius estimation theory, a Minimizing the Increment of Spectral Radius (MI SR) resource block sharing algorithm is proposed to accommodate as many users as possible. Finally, simulation results show that the proposed MISR algorithm can improve spectrum efficiency by 150% and 96% in rush hour compared with some other existing methods.Considering frequent cell handovers in V2V communication, a fast and accurate handover control scheme is proposed. Taking the advantage of vehicle status information, the time to trigger measurement report is shortened. For improving the accuracy of handover decision,transmission and receiving vehicles are combined together to make joint handover decision. Moreover, they are put into a group and make group handover to reduce signaling overhead of eNodeB. The handover resource is allocated to transmission vehicle during handover interruption to ensure the continuity of V2V communication. Besides, a priority-based resource allocation scheme is designed to ensure handover resource for users with high priority.A downlink broadcast scope selection mechanism in Uu interface V2X communication is proposed in this thesis in order to adapt to the dynamic change of the scope, wherein the set of cells affected by the V2X message is determined based on the measurement of serving cell and neighboring cells' RSRPs,and the differences of RSRPs reveal the relative position information of transmission vehicle. Then the V2X message is cached in advance to the eNodeBs on the route of transmission vehicle to reduced latency. To avoid the reception of vehicles outside the influence scope of the V2X message, the mechanism of scrambling V2X message using a GroupID broadcast by transmission vehicle is used.In summary, this thesis studies three research points about resource management of LTE-based V2X communication. Corresponding resource allocation algorithm, optimized handover scheme and solution of broadcast area selection are proposed respectively, with part of proposed solutions verified by simulation.