基于SSC-DPIM电力线载波通信的列车信息集中监控系统

A Passenger Train Information Monitoring System Employing SSC-DPIM Power Line Communication Technique

分析了列车低压电力线网络的信道特性,提出一种扩频载波数字脉冲间隔调制(SSC-DPIM)电力线载波通信系统.采用线性扫频SSC扩频载波对DPIM符号进行编码,引入脉冲前导码作为传输数据块的同步信号以防止差错传播.并采用单片机实现了该SSC-DPIM系统,研制了电力线载波通信接口收发控制器和列车行车状态监控器,使其在呈时变、高信号衰减特性并存在复杂干扰的列车低压电力线网络上实现了理想的通信,对列车各车厢行车信息进行集中监测.

Train power lines provide a readily available and easily accessible network for measurement and control of unit communications within trains. The communication characteristics of passengertrain power line channels are analyzed and found to suffer from highly variable, changing, and unpredictable signaltonoise ratios. Power line transceivers usually operate in environments containing both background and strong impulse noise. To reduce the effects of the power noise and interference, a powerline spreadspectrum carrier communication system using digital pulseinterval modulation (SSCDPIM) is proposed. In the system, a sweptfrequency spreadspectrum carrier is used to generate pulses of the DPIM. A mathematical model to describe the signaling and the data transmission rate of the SSCDPIM system is given. The error ratio performance of the SSCDPIM system is compared with that of the established techniques of powerline communications using both theoretical analysis and experimental results. The SSCDPIM transceiver is implemented by a microprocessor and used successfully in a train fault monitoring system based on power line communications. In the monitoring system, the running parameters of trains such as axle temperature, miles operated, power load, sensor states and so on, are measured on the spot and transmitted into a train signal monitoring center simultaneously by power line channels.