Analysis of OFDM Applied to Powerline High Speed Digital Communication

The low voltage powerline is becoming a powerful solution to home network, building automation, and internet access as a result of its wide distribution, easy access and little maintenance. The character of powerline channel is very complicated because it is an open net. This article analysed the character of the powerline channel,introduced the basics of OFDM(Orthogonal Frequency Division Multiplexing), and studied the OFDM applied into powerline high speed digital communication.

OFDM-based Low-voltage Powerline High Rate Communication

Based on the experimental results, a simplified model for low-voltage powerline used as a high frequency communication channel is presented. With this model, the Orthogonal Frequency Division Multiplexing (OFDM) based high rate digital communication over low-voltage powerline is analyzed and simulated. The capability of the signal transmission system in overcoming multi-path interference and selection of the system parameters are discussed. And time-domain simulation is carried out to investigate the transmission capability of the OFDM communication system for different mapping schemes and transmission power levels. Simulation results show that it is possible to realize high rate digital communication over low-voltage powerline using OFDM when the transmitted power is large enough.

Time Domain Modeling of Powerline Impulsive Noise at Its Source

Noise characteristics of an indoor power line network strongly influence the link capability to achieve high data rates. The appliances shared with PLC modems in the same powerline network generate different types of noises, among them the impulsive noises are the main source of interference resulting in signal distortions and bit errors during data transmission. With regard to impulsive noise many models were proposed in the literature and shared the same impulsive noise definition: “unpredictable noises measured in the receiver side”. Authors are, consequently, confronted to model thousands of impulsive noises whose plurality would very likely come from the diversity of paths that the original impulsive noise took. In this paper, an innovative modelling approach is applied to impulsive noises which are studied here directly at their sources. Noise at receiver would be simply the noise model at source convolved by powerline channel block. In the new analytical model, the impulsive noise at source is described by a succession of short pulses, each modeled by a phase-shifted Gaussian. Noises at source are classified into 6 different classes [1], and a noise generator is established for each class.

MTU机车用Powerline自动化系统

MTU公司针对液力传动内燃机车和电传动内燃机车驱动系统开发出Powerline创新型系统自动化方案,专用于机车的MTU柴油机。介绍了该系统的结构、功能原理及其先进性。

FINDING THE OPTIMAL LENGTH OF DATA FRAME IN PLC COMPUTER NETWORK

The length of data frame is an important parameter in Medium Access Control(MAC) layer protocol. A method of finding the optimal length of data frame when impulsive disturbance is involved in PowerLine Communications (PLC) is proposed. Having analyzed the characteristics of impulsive disturbance in powerline and the collision mechanism between the disturbance and data frame, this letter gives the function of the network channel utilization with the length of data frame in MAC layer and the impulsive disturbance. Our stochastic process simulation shows that it is feasible to get the optimal length of data frame.

基于FPGA的Ethernet Powerlink通信节点的设计与实现

针对目前运动控制系统对现场总线的实时性要求日益增高这一问题,分别以FPGA+PHY网络芯片、Nios II软核处理器作为基本硬件和软件平台,结合Powerlink开源协议,设计并实现最小循环周期为500的通信节点(从站),从而保证运动控制系统通信的实时性。

LDPC Coded TDS-OFDM for PLC Systems

Powerline communications （PLC） have drawn great interest in recent years. However, most PLC standards such as HomePlug AV use the cyclic-prefix OFDM （CP-OFDM） technology. This paper presents a broadband PLC system using low density parity check （LDPC） coded time domain synchronous OFDM （TDS-OFDM）, whose spectrum efficiency is about 10% higher than that of CP-OFDM. With the same bandwidth and the ability to combat the time delay spread as HomePlug AV, this system can provide a maximum throughput of 199.7 Mbps physical layer data rate. Simulations over the measured practical powerline channel in Beijing, China, show that LDPC in the TDS-OFDM system dramatically improves the bit error rate performance, and verify the feasibility and performance of the TDS-OFDM technology for PLC systems.

Two-Way Digital Video Transmission over Medium-Voltage Power-Lines Using Time-Domain Synchronous Orthogonal Frequency Division Multiplexing Technology

This paper describes field trials of two-way digital video transmissions over a 700-m long medium-voltage power cable using a frequency division duplex scheme. The purpose is to check the feasibility of using time-domain synchronous orthogonal frequency division multiplexing （TDS-OFDM） technology in powerline communication （PLC）. TDS-OFDM is the core technology in digital multimedia broadcasting-terrestrial （DMB-T）, developed by Tsinghua University for digital television terrestrial multimedia broadcast applications and successfully adopted in the Chinese Digital Terrestrial Television Broadcasting Standard. PLC systems are widely believed to be bandwidth or data throughput limited. However, the use of known pseudo random sequences as guard intervals for synchronization and channel estimation in TDS-OFDM greatly reduces the system overhead and increases the spectrum efficiency. These experiments show that TDS-OFDM is appropriate not only for broadcasting but also for PLC applications with appropriate modifications.

MTU公司内燃机车自动化动力控制系统

MTU公司的"Powerline"动力控制系统产品,提供了液力传动及电传动内燃机车柴油机动力控制系统的一套总体设计。不论是新造机车,或是更换动力的机车,其动力控制系统的模块式结构都具有高度的灵活性,并使集成尽可能方便。由于MTU公司在世界范围内的服务网络和30年以上的配件保证,可以用完机车的全部寿命期。本文分析了机车动力控制系统集成的各种可能性,并说明了各种动力控制系统核心部件的作用。介绍了铁路相关标准的发展,MTU公司的质量管理及可靠性管理,按V形模式进行的产品开发,软件管理系统,配件供应,电子装置的制造,咨询、设计、调试和服务,以及MTU"Powerline"动力控制系统对于机车制造商和机车运营商的益处。