Proposal of Cooperative Communication to Enhance Accuracy of Wireless Control Systems

Control systems are being changed from wired to wireless communications because of flexibility, mobility and extensibility of wireless communication systems;however the reliability of wireless communications is suspected. In this paper, we propose cooperative communication scheme for wireless control systems which consist of a controller and multiple machines;these machines cooperatively work in a group and for the same duty. In the proposed method, the controller can communicate with machines directly or via other machines, whereas in the conventional method, the controller only communicates with machines directly. The simple 2-link arm plant is used to evaluate our proposed system, and the simulation results indicate that the proposed method is more accurate, and more stable than the conventional method.

A Wireless Solution for Train Switchgear Contact Temperature Monitoring and Alarming System Based on Wireless Communication Technology

We present a temperature monitoring and warning system, which is based on wireless communi- cation technology and applied in train switchgear in this paper. The system is consists of three parts, including wireless temperature detection module, inter-vehicle transmission networks module and?remote monitoring server. The switchgear contact temperature data are collected via the wireless temperature detection module and exchanged in inter-vehicle wireless networking by Zigbee modules. Then the temperature of train switchgear cabinets can be monitored remotely through the GPRS wireless communication.

A Clustering-tree Topology Control Based on the Energy Forecast for Heterogeneous Wireless Sensor Networks

How to design an energy-efficient algorithm to maximize the network lifetime in complicated scenarios is a critical problem for heterogeneous wireless sensor networks(HWSN).In this paper, a clustering-tree topology control algorithm based on the energy forecast(CTEF) is proposed for saving energy and ensuring network load balancing, while considering the link quality, packet loss rate, etc. In CTEF, the average energy of the network is accurately predicted per round(the lifetime of the network is denoted by rounds) in terms of the difference between the ideal and actual average residual energy using central limit theorem and normal distribution mechanism, simultaneously. On this basis, cluster heads are selected by cost function(including the energy, link quality and packet loss rate) and their distance.The non-cluster heads are determined to join the cluster through the energy, distance and link quality. Furthermore, several noncluster heads in each cluster are chosen as the relay nodes for transmitting data through multi-hop communication to decrease the load of each cluster-head and prolong the lifetime of the network. The simulation results show the efficiency of CTEF. Compared with low-energy adaptive clustering hierarchy(LEACH), energy dissipation forecast and clustering management(EDFCM) and efficient and dynamic clustering scheme(EDCS)protocols, CTEF has longer network lifetime and receives more data packets at base station.

Guest editorial: special issue on high mobility wireless communications

The high-speed railway and high-way networks are now expanding at a phenomenal speed in Chinaand in many other parts of the world. The related broadband wireless communication over high-speed trains and highway vehicles is a very challenging task due to hostile transmission channel conditions. The demand for such services is growing rapidly, following the proliferation of laptop/tablet computers and smart phones. This motivates the research on wireless communications in the high mobility environments.

Class of Service Support Layer for Wireless Mesh Networks

This paper presents an add-on Class of Service (CoS) layer for wireless mesh networks. The proposed protocol is applicable for contention-based MACs and is therefore compatible with most of the Wireless Local Area Network (WLAN) and Wireless Sensor Network (WSN) protocols. The protocol has a locally centralized control for managing data flows, which either reserve a fixed bandwidth or are weighted by fair scheduling. The protocol reduces transmission collisions, thus improving the overall throughput. IEEE 802.11 adhoc WLAN has been taken as a platform for simulations and prototyping for evaluating the protocol performance. Network Simulator Version 2 (NS2) simulations show that the CoS protocol efficiently differentiates bandwidth, supports bandwidth reservations, and reaches less than 10 ms transfer delay on IEEE 802.11b WLAN. Testing with a full prototype implementation verified the performance of the protocol.

Designing of New Data Synchronization System

As the rapid development of Wireless Communications and the popularity of the Intelligent Terminal, data synchronization has been a social focus, meanwhile, user terminal devices are increasingly diversified, traditional synchronization technology based C/S mode has such deficiencies as insufficient amount of transmitting data and bad Real-time efficiency. It has become increasingly unable to meet the needs of future development. In this paper, we proposed and designed a new method and system by separating control with transmission to synchronize data to ensure Real-time data and improve efficiency.

Energy efficiency optimization of relay-assisted D2D two-way communications with SWIPT

Aiming at the energy consumption of long-distance device-to-device(D2D) devices for two-way communications in a cellular network,this paper proposes a strategy that combines two-way relay technology(TWRT) and simultaneous wireless information and power transfer(SWIPT) technology to achieve high energy efficiency(EE) communication.The scheme first establishes a fractional programming problem to maximize EE of D2D,and transforms it into a non-fractional optimization problem that can be solved easily.Then the problem is divided into three sub-problems:power control,power splitting ratios optimization,and relay selection.In order to maximize EE of the D2D pair,the Dinkelbach iterative algorithm is used to optimize the transmitted power of two D2D devices simultaneously;the one-dimensional search algorithm is proposed to optimize power splitting ratios;an improved optimal relay selection scheme based on EE is proposed to select relay.Finally,experiments are carried out on the Matlab simulation platform.The simulation results show that the proposed algorithm has faster convergence.Compared with the one-way relay transmission and fixed relay algorithms,the proposed scheme has higher EE.

Model-Free Adaptive Frequency Calibration for Voltage-Controlled Oscillators

The operating frequency accuracy of the local oscillators is critical for the overall system performance in the communication systems.However,the high-precision oscillators could be too expensive for civil applications.In this paper,we propose a model-free adaptive frequency calibration framework for a voltage-controlled crystal oscillator(VCO)equipped with a time to digital converter(TDC),which can significantly improve the frequency accuracy of the VCO thus calibrated.The idea is to utilize a high-precision TDC to directly measure the VCO period which is then passed to a model-free method for working frequency calibration.One advantage of this method is that the working frequency calibration employs the system history of input/output(I/O)data,instead of establishing an accurate VCO voltagecontrolled oscillator model.Another advantage is the lightweight calibration method with low complexity such that it can be implemented on an MCU with limited computation capabilities.Experimental results show that the proposed calibration method can improve the frequency accuracy of a VCO from±20 ppm to±10 ppb,which indicates the promise of the modelfree adaptive frequency calibrator for VCOs.

Overview of Key Technologies for Remote Wireless Operation Platform on Water Surface

The underwater environment is complicated and full of hazards,making it tough to complete with just one piece of underwater operation equipment.Building a high-speed,low-latency wireless connection between a remote wireless operation platform on water surface and other operation platforms in order to achieve long-distance transmission of high-definition image data and control commands,as well as collaborative operations among multiple platforms,has become a development trend and focus of exploring complex and dangerous waters.This paper summarizes and elaborates on underwater communication technology,long-distance data transmission technology,multi-submersible robot collaborative operation,and information interaction technology,as well as the development status of key technologies of remote wireless operation platform on water surface.And the research direction and focus of the remote wireless operation platform on water surface are prospected.

Dependability analysis of the data communication system in train control system

Communication based train control (CBTC) system is based on mobile communication and overcomes fixed blocks in order to increase track utilization and train safety. The data communication system (DCS) between trains and wayside equipment is a crucial factor for the safe and efficient operation of CBTC system. The dependability under various transmission conditions needs to be modeled and evaluated. In this paper,a stochastic reward net (SRN) model for DCS based IEEE 802.11 standard was developed,which captures all relevant failure and failure recovery behavior system aspects in a concise way. We compared the reliability,availability for DCS with and without access point (AP) and antenna redundant configuration. We also quantitatively evaluated and compared the frame loss probability for three DCS configurations with different train velocities and train numbers in one radio cell. Fixed-point iteration was adopted to simplify the analysis. Numerical results showed the significant improvement of the reliability,availability and the frame loss probability index for the full redundant configuration.

Analysis of the different locomotive wireless multi-traction synchronous control systems for heavy-haul combined trains and their performance

This paper looks at the heavy-haul combined train composed of different types of locomotives and its distributed power control system with a combination of 800 MHz and TD-LTE wireless communication.It analyses some key characteristic parameters that affect the synchronism and communication of the differential wireless multi-traction synchronous control systems for heavy-haul combined trains.At the same time,in order to reduce the latency of instruction and information transfer between different types of locomotives,improve the time-limit certainty of wireless transmission and optimize the control quality of multi-traction control systems for heavy-haul combined trains,a synchronism optimization strategy based on the Markov decision process on the basis of Petri networkconstruction is proposed.Relevant experiments and tests are carried out to verify the effectiveness of the synchronism optimization of the control system,which provides a guarantee for improving the differential wireless multi-traction synchronous control system for combined trains and optimizing train control.

基于压缩感知的车地传输数据压缩算法研究

动车组车地无线传输受限于移动网络带宽限制,数据传输间隔较长,无法准确反映车载系统运行状态,提出了一种基于压缩感知的车地传输数据压缩算法,能够在地面高精度地还原车载原始数据的同时,大幅压缩车地传输数据量,提高了车地带宽利用率,为动车组运行监测和故障应急指挥提供了更详实的数据支撑。

基于通信网络的列车控制系统

自动组网(初运行)是列车控制与管理系统(TCMS)的重要特征,通过初运行,确定列车通信网络(TCN)内的节点组成、节点之间的顺序、总线主以及各个节点相对总线主的朝向,这是TCMS对列车进行控制与管理的基础。对于基于无线通信的TCMS,由于无线列车骨干网(WLTB)的网络节点之间没有通信线缆的物理连接,以传统的方式实现自动初运行十分困难,因此实际工程中采用人工设置参数的方式来组网。同样,在虚拟联挂(VC)系统中,多列列车通过WLTB组成列车编队,也存在动态自动组网的问题。在VC系统中,由于跟随列车处于自动驾驶模式,通过人工设置参数来组网的方式也不可行。文章分析了TCN、WLTB的初运行和VC列车编队/解编,探讨了基于无线通信的列车编组初运行或编队动态组网问题的实质与根源,提出通过引入一个更大的网络系统、融合TCMS和信号系统来解决自动组网问题的方法,基于列车控制的视角给出了面向列车全自动运行的基于通信网络的列车控制(NBTC)系统自动组网方法、分层次功能和系统架构,并提出了与NBTC相关的研究方向。

CTCS3-300H型列控车载设备状态在线监测与智能分析系统开发与应用

针对CTCS3-300H型列控车载设备(简称:列控车载设备)各单元运行日志数据分散存储、数据转储下载接口多、数据分析工作繁琐耗时的问题,根据列控车载设备结构特点,设计了列控车载设备状态在线监测及智能分析系统。该系统统一了列控车载设备各单元的日志数据采集与传输接口,借助既有的车地无线传输通道,设计了灵活、务实的车地数据传输方案,实现了用于列控车载设备状态在线监测的事件通告报文的实时传输,提供故障日志自动下载、手动按需下载两种日志数据无线下载方式,在满足列控车载设备状态在线监测和故障分析需要的前提下,最大限度地减少车地数据传输量。通过有效利用列控车载设备日志数据进行智能分析,能够快速、准确定位故障原因,实现故障自动报警并给出处置建议,提高了列控车载设备故障应急处置和维护效率,为动车组安全运行提供强有力的技术保障。

一种基于无线专网的CTC3.0多岗位联动技术方案

在调度集中系统3.0(Centralized Traffic Control System 3.0,CTC3.0)推广使用过程中,对于接发车作业中的流程管理功能,因覆盖岗位多,需要通过多岗位联动来实现接发车作业流程的流转,尤为获得车站的关注与重视。通过分析车站运输生产过程中的接发车作业流程业务,结合CTC3.0作业流程管理功能,探讨一种基于无线专网的CTC3.0多岗位联动技术方案,以期在未来的实践中,实现CTC3.0车站接发车作业流程管理数字化,减轻车站人员的作业负担。

基于监测数据的ATP车载电台健康状态评估算法研究

在列车运行过程中,ATP车载电台运用不稳定会引起车地无线通信超时,导致CTCS-3级列控系统降级,影响列车运行效率。针对此类问题,通过研究电台多种常见故障及特征,设计一套用于ATP车载电台健康状态评估的算法。以接口监测数据、基站空口监测数据和车载空口监测数据为基础,通过学习与迭代,建立表征电台健康状态的模型作为评分基准;通过对比电台相关特征值与模型基准值,对各个电台进行健康状态评估。经验证,该算法可准确描述车载电台的健康状态,供运维人员对健康状态差的电台提前处理,从而实现电台故障的事前预防,对降低CTCS-3级列控系统无线通信超时概率、保障列车安全运行、提高铁路运维水平等具有重要意义。

Application of wireless sensor networks to aircraft control and health management systems

Use of fly-by-wire technology for aircraft flight controls have resulted in an improved performance and reliability along with achieving reduction in control system weight. Implementation of full authority digital engine control has also resulted in more intelligent, reliable, light-weight aircraft engine control systems. Greater reduction in weight can be achieved by replacing the wire harness with a wireless communication network. The first step towards fly-by-wireless control systems is likely to be the introduction of wireless sensor networks (WSNs). WSNs are already finding a variety of applications for both safety-critical and nonsafety critical distributed systems. Some of the many potential benefits of using WSN for aircraft systems include weight reduction, ease of maintenance and an increased monitoring capability. This paper discusses the application of WSN for several aircraft systems such as distributed aircraft engine control, aircraft flight control, aircraft engine and structural health monitoring systems. A brief description of each system is presented along with a discussion on the technological challenges. Future research directions for application of WSN in aircraft systems are also discussed.

Admission Control Scheme for Handover Service in High-Speed Train Communication System

Admission control in high-speed train communication system is quite different from admission control in traditional cellular networks. Conventional admission control strategies cannot be directly applied to this special communication scenario. In this paper, the problem of admission control for handover service is investigated in high-speed train communication environment. An admission control scheme considering bit error rate(BER)and bandwidth borrowing strategy is proposed. On the basis of admission control decision rule taking BER into account, a part of bandwidth obtained by compressing variable rate service in the networks is provided for handover services. The admission control scheme can admit handover services as more as possible while it guarantees the lowest data rate of different services in the networks. Simulation results show that the proposed admission control scheme has a better performance than existing admission control schemes.

西门子Trainguard MT车载无线通信系统RCS的安装

文章介绍了西门子Trainguard MT列车控制系统中实现车地无线通信的关键设备——车载无线通信系统RCS,阐述了其设备组成、安装方法与技术要点。

基于时延补偿的高速列车无线网络多幂次滑模控制策略

无线网络时延的存在是制约高速列车无线通信网络发展的关键问题。通过搭建无线网络控制半实物试验平台获取时延样本,针对无线时延序列复杂度高的特点,提出互补集合经验模态分解(Complementary Ensemble Empirical Mode Decomposition,CEEMD)与奇异值分解(Singular Value Decomposition,SVD)相结合的处理方法,并引入样本熵降低运算量,最终通过混沌粒子群算法优化最小二乘支持向量机(Least Square Support Vector Machine,LSSVM)模型,完成时延预测;以高速列车牵引制动模块为被控对象,设计基于多幂次趋近律的滑模控制器进行时延补偿,采用混沌粒子群算法对控制器参数进行智能寻优,将ITAE指标(Integrated Time and Absolute Error)改进为ITAE*作为适应度函数,以减小跟踪误差,提高响应速度。结果表明:经CEEMD分解后最大分量样本熵由原来的2.7以上降至2.0以下,采用SVD对最大样本熵的本征模函数(Intrinsic Mode Function1,IMF1)分量进行二次处理后,其样本熵降至1.5以下,有效降低了预测难度;改进后的时延预测均方误差(Mean Square Error,MSE)、平均绝对误差(Mean Absolute Error,MAE)和平均绝对百分误差(Mean Absolute Percentage Error,MAPE)分别降至0.139 6,0.296 4和0.008 3,预测精度有所提高;对于较长时延,进行时延补偿控制后其ITAE*指标仅为补偿前的0.136%,速度跟踪累计绝对误差为补偿前的0.696%,高速列车运行状态改变时速度跟踪曲线无明显抖振现象,同时当高速列车遇到扰动时速度跟踪曲线可快速回归平稳状态。研究成果可为高速列车引入无线网络控制提供一种新的方法。