A tdma-based adaptive time slot allocation method for vehicular ad hoc networks

Abstract

The invention relates to a vehicle-mounted ad hoc network self-adaptive time slot distributing method based on a time division multiple address (TDMA), the vehicle-mounted ad hoc network self-adaptive time slot distributing method divides a time frame into a left time slot set and a right time slot set, nodes are divided into a left node set and a right node set based on the moving direction of the nodes, and the nodes in the left / right node sets choose competition time slots in the left / right time slot set based on the current geographical location information and according to certain rules. The vehicle-mounted ad hoc network self-adaptive time slot distributing method based on the TDMA reduces the ratio of a connect-in confliction and an amalgamation confliction occurred by the nodes to a large degree; and based on density changes of the nodes sensed by the nodes, the lengths of frames are dynamically adjusted, so that the demand that the nodes swiftly connect-in channels is satisfied; low time delay of the vehicle-mounted ad hoc network self-adaptive time slot distributing method based on the TDMA is authenticated by both theoretical analysis and simulating experiments. Compared with the prior art, the vehicle-mounted ad hoc network self-adaptive time slot distributing method based on the TDMA has the advantages of having less quantities of confliction nodes, higher utilizing ratio of the channels and good expansibility.

Description

technical field [0001] The invention relates to a TDMA-based vehicular ad hoc network self-adaptive time slot allocation method, which belongs to the technical field of vehicular communication. Background technique [0002] Vehicle Ad-hoc Networks (VANET for short) is a distributed, self-organizing network composed of mobile vehicles equipped with wireless transceiver modules (herein referred to as nodes) and roadside units (Roadside Units, referred to as RSUs). The mode includes self-organizing multi-hop communication between nodes (V-2-V: Vehicle to Vehicle) and communication between nodes and RSU (V-2-I: Vehicle to Infrastructure). [0003] As one of the important foundations of intelligent transportation systems, VANET has important applications in alleviating traffic congestion, sharing traffic information in real time, safety warning, and assisting driving [1], and is currently becoming a research hotspot in the industry and academia , and the MAC protocol is how to m...

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Problems solved by technology

[0007] The purpose of the present invention is to provide a kind of self-adaptive time slot allocation method of vehicular ad hoc network based on TDMA, to solve the current channel allocation method in vehicular ad hoc network using CSMA / CA protocol and the improved MAC protocol based on it when the density is large In the vehicle environment, it is easy to cause access conflicts, leading to the problem of increased delay, and the use of fixed TDMA frame length protocol results in low channel utilization in sparsely noded areas, and some nodes may not be able to access in densely populated areas. network access issues

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