铁路应急通信网络组呼的组播路由算法分析

摘要

To meet the demand of constructing GSM-R railway emergency communication network, a new multicast routing algorithm (REGCA) and its algorithm flow were presented for group call in GSM-R supported railway emergency communication network based on improving the typical multicast routing algorithm ODMRP. In the algorithm, some control strategies such as restricting listeners from speaking, limiting flooded area and allowing automatically joining in temporary multicast were added. With NS2 simulation tool, the simulation model of ad hoc network for Wuhan-Guangzhou high-speed railway emergency communication system was established. Then, corresponding simulation scene was built according to the established model to simulate and analyze REGCA algorithm. Results show that REGCA algorithm can greatly alleviate network load, improve packet delivery ratio, as well as reduce end-to-end transmission delay and routing overhead. In various scenarios, REGCA's packet delivery ratio reaches above 80%. At the same time, the average end-to-end transmission delay remains below 0. 4 s. It verifies that REGCA algorithm can satisfy the requirement for group call in GSM-R railway emergency communication environment%从建立GSM-R铁路应急通信网络的需要出发,在组播路由算法ODMRP的基础上通过改进,提出1种支持GSM-R铁路应急通信网络组呼的组播路由新算法(REGCA)及其算法流程.在该算法中加入了抑制听者发言、限制洪泛区域以及允许自动加入临时组播等控制策略.使用NS2仿真工具建立武广高铁应急通信系统自组网仿真模型,然后根据模型建立相应的仿真场景,对REGCA算法进行仿真分析.仿真结果表明,采用REGCA算法能够大大减轻网络负载、提高分组投递率、降低端到端传输时延和路由开销；采用REGCA算法在各种仿真场景中的分组投递率均达80％以上,端到端传输平均时延均在0.4s以下,能够满足GSM-R铁路应急通信环境下的组呼要求.