Downlink Wireless Resource Scheduling Method Based On TD-LTE In Vehicle Road Communication Access System

Vehicle road communication access system is an important research content of the next generation intelligent transportation systems(ITS). The latest commercial TD-LTE technology has wide coverage, high communication rate, small transmission delay and other characteristics, which is especially suitable for multimedia messaging between vehicles and road in the future. Downlink resource scheduling of real-time information wireless transmission is one of the technical difficulties. This paper does deeply study on downlink resource scheduling method of the vehicle road communication access system based on TD-LTE, the main work includes:1. The feasibility of introducing TD-LTE technology to vehicle road communication access system is analyzed. On this basis, An ITS vehicle road communication solution based on TD-LTE is proposed. In this program, the total vehicle road communication system is divided into three layers: from bottom to top, it is the wireless access layer, the core network layer and the traffic cloud layer. At the same time, the basic elements and functions of each layer have been clear.2. The downlink wireless resource management mechanism of the vehicle road communication access system based TD-LTE is studied, and the role and function of different resource management entities, signals are analyzed in downlink wireless resource allocation process. On this basis, a downlink wireless resource scheduling model is established.3. The existing classical scheduling algorithm is analyzed. The advantages and disadvantages, business and scene of each algorithm are discussed. On this basis, A downlink wireless resource allocation algorithm named M-EDFPF-V2 I is proposed. This algorithm introduces the information service flow type weights to scheduling function model, so that the system always gives the right scheduling priority to the flow associated with real-time information. Then the algorithm introduces the QoS differentiation weights to scheduling function model, so that the system can meet real-time flow QoS requirements, particularly those related to traffic safety information service, while ensuring the effectiveness of other real-time transmission of business. For the non-real-time traffic, the algorithm allocates the wireless resources based on channel quality and transmission speed of history, taking into account the system speed and user fairness at the same time.4. A suitable vehicle road communication access system simulation platform is built based on an open source framework named LTE-Sim. Typical transportation communication scenes are built to validate downlink radio resource scheduling algorithms. Simulation results show that, M-EDFPF-V2 I gives right priority to real-time safety-related information flow, ensures other emergency real-time traffic dispatching in time, and reduces the packet loss rate of real-time flow. The algorithm has optimum scheduling effect.The research results have a reference value for applying TD-LTE technology to vehicle road communication field and the study of downlink wireless resource scheduling algorithms.