自动控制文献翻译——摘要—无线传感器网络（WSN）技术近来的发展激发了人们对车辆故障监测（VHM）系统发展的兴趣。它们有潜在的可能性运用在铁路信号监测系统和铁路轨道上。节能是无线传感器网络最重要的设计因素之一，因为典型的传感器配备的是能量有限的电池。在早期的研究中，学者们发明了一种节能型分簇自适应时分多路（TDMA）媒介访问控制（MAC）协议，即EA-TDMA. 本文介绍了另一种叫做E-BMA的新协议, 它通过对竞争阶段的闲散时间最小化来获得较好的节能效果。除了在铁路上的应用， EA TDMA和E - BMA协议也适用于一般的无线数据通信。就TDMA, EA-TDMA, BMA,和 E-BMA这几个协议在能量消耗上的分析和模拟结果来说，本文展示了EA-TDMA 和 E-BMA协议的优势。

关键词—节能，媒介访问控制（MAC）协议，铁路货车，车辆故障监测（VHM），无线传感器网络（WSN）

1.引言

随着铁路维护需求的增加，铁路监控系统以惊人的速度持续发展，以保证列车可靠、安全运行。铁路基础设施的安全性和安全监测的缺乏会引起列车碰撞，列车脱轨，恐怖分子威胁，货物列车故障等事故。轨道几何检测和监测提高了列车运行的安全性并减少了车辆和轨道动态的相互作用。各研究机构已解决了从实时轨道测量数据中监测车辆特性的问题。无线传感器网络（WSN）广泛应用于铁路轨道的监测，开发了入侵检测系统，确保铁路运营。

无线传感器网络技术监测铁路货车故障状况的潜力已被完全开发。电池的寿命有限，功率传感器使得无线传感器网络的节能是一个主要的设计问题。本文的研究主要集中在节能无线传感器网络MAC协议的发展，从放置在铁路货车旁的传感器上采集数据，并将数据发送给机车作为进一步的预防措施以防止任何未知的灾难性事件。

2.基于计划的媒介访问控制协议

无线MAC协议的主要要求是：节能，可扩展性，延迟，公平和带宽利用率。基于竞争的协议对于网络密度和交通负荷的变化具有可扩展性和适应性。然而，这些协议有一个主要的限制，即大量的能源浪费。基于计划的协议无碰撞，因此，减少了因碰撞产生的能量损耗。然而，他们缺乏基于竞争的MAC协议固有的灵活性和可扩展性。

时分多路（TDMA）是一种基于计划的MAC协议，其传输信道被分为若干时隙，每个网络分配一个时隙。每个网络只有在其分配的时隙被唤醒并发送数据，在剩余时隙保持在睡眠模式。节能TDMA（E-TDMA）由于空隙侦听降低了能源消耗。传感器网络在没有数据发送时会将无线电关闭。然而，CH一直保持无线电开启因此浪费能源。

位图辅助（BMA）协议是另一个基于计划的协议，旨在减少因碰撞和空隙侦听产生的能量损耗。群集安装阶段与LEACH协议相类似。在竞争阶段，......

Abstract—Recent advances in wireless sensor networking (WSN) techniques have encouraged interest in the development of vehicle health monitoring (VHM) systems. These have the potential for use in the monitoring of railway signaling systems and rail tracks. Energy efficiency is one of the most important design factors for the WSN as the typical sensor nodes are equipped with limited power batteries. In earlier research, an energy-efficient cluster-based adaptive time-division multiple-access (TDMA) medium-access-control (MAC) protocol, named EA-TDMA, has been developed by the authors. This paper proposes another new protocol, named E-BMA, which achieves even better energy efficiency for low and medium traffic by minimizing the idle time during the contention period. In addition to railway applications, the EA-TDMA and E-BMA protocols are suitable for generic wireless data communication purposes. Both analytical and simulation results for the energy consumption of TDMA, EA-TDMA, BMA, and E-BMA have been presented in this paper to demonstrate the superiority of the EA-TDMA and E-BMA protocols. 

Keywords—Energy efficiency, medium access control (MAC) protocol, railway wagon, vehicle health monitoring (VHM), wireless sensor network (WSN).

I. Introduction

With the increased demand for railway services, railway monitoring systems continue to advance at a remarkable pace to maintain reliable, safe, and secure operation. The lack of safety and security monitoring of railway infrastructure runs the risk of train collision, train derailment, terrorist threats, failures in the train wagons, etc. Track geometry inspection and monitoring enhances train-operating safety and reduced vehicle and track dynamic interaction. Monitoring vehicle characteristics in real time from track measurement data has been addressed by various research organizations. Wireless sensor networks (WSN) are widely used to monitor railway tracks and irregularities, develop intrusion detection systems, secure railway operations. 

The potential of WSN technology to monitor the railway-Wagon health condition and the vertical displacement of railway wagons due to track irregularities has yet to be fully explored. The limited lifetime of the batteries that power the sensor makes the energy efficiency a major design issue for WSN. This paper concentrates on developing an energy-efficient WSN MAC protocol to collect data from sensor that are placed inside the railway wagons and send the data to the locomotive for further precautionary .......