In order to optimize the communication mechanism in the vehicular adHoc networks (VANETs), this paper presents an enhanced TDMA based cooperative MAC protocol called EVC-TDMA. In EVC-TDMA, when the vehicles need to transmit multi-hop messages, they choose relay nodes dynamically according to the relative speeds and buffer lengths. By monitoring the broadcasting messages, the other nodes can know the buffer lengths of the relay nodes, they will help transmit the relay messages when their buffer are idle or less. Considering the data arrive follows a Poison Point Process, this paper analyzes the nodes' buffer length based on a two-dimension Markov process. The simulation results show that EVC-TDMA can reduce the dropping rate and improve the throughput of the network.

中文翻译：

---

EVC-TDMA：一种用于车载网络的基于增强型 TDMA 的协作 MAC 协议

为了优化车载自组织网络 (VANET) 中的通信机制，本文提出了一种称为 EVC-TDMA 的基于增强型 TDMA 的协作 MAC 协议。在 EVC-TDMA 中，当车辆需要传输多跳消息时，它们根据相对速度和缓冲区长度动态选择中继节点。通过监听广播消息，其他节点可以知道中继节点的缓冲区长度，当他们的缓冲区空闲或更少时，他们将帮助传输中继消息。考虑到数据到达遵循毒点过程，本文基于二维马尔可夫过程分析节点的缓冲区长度。仿真结果表明，EVC-TDMA可以降低丢包率，提高网络吞吐量。