【作者】 牟英峰；

【导师】 徐殿国；

【作者基本信息】 哈尔滨工业大学 ， 电力电子与电力传动， 2007， 博士

【摘要】 电力线宽带接入网、局域网和基于电力线通信的大规模监控系统的发展,对电力线通信网络的可靠性提出了更高的要求。在电力线通信节点组网时,可靠性问题的关键是在变化的信道条件下,节点间通信链路是否能够可靠连接。在以往的文献和研究成果中,针对电力线通信网络可靠性的研究较少;本文从理论和工程应用两个方面对提高电力线通信网络连通性及有效性的方法进行了较为深入的研究。分析前人研究的电力线信道输入阻抗、噪声、反射特性和信道模型,从中归纳出电力线信道的动态特性;分析电力线通信网络可靠性相关的已有成果,结合电力线通信网络应用和研究的现状,提出了电力线通信连通性问题是在大规模节点组网条件下,迫切需要解决的基础问题。应用OSI模型的系统分层方法,研究并指出现有电力线通信网络缺乏可互联的网络层功能,在MAC层上增加网络层的功能是十分必要的,并能以较小的代价和硬件开销实现这一功能。深入研究了电力线通信网络的可重构特性,指出电力线通信网络的逻辑重构问题即初始化问题。通过分步骤的重构初始化,提出了可重构的引理,进一步提出并证明了多级分层策略下的可重构算法。阐明了重构算法与普通中继网络的区别和同步方法;并指出了可重构算法位于受物理层限制较小的MAC层,这一特点对于现有电力线通信网络的硬件平台具有普遍的适应性。进一步研究逻辑重构后的网络拓扑,给出一种适用于混合电力线通信网络的低成本的类-TDMA的MAC层协议;应用M/D/1模型,与轮询系统对比,分析了协议的性能。分析了实际应用对重构算法的限制,给出了经过验证的工程算法,以及远程监控系统感兴趣的通用循环周期。与重构初始化算法同样地适应硬件平台,进行了基于累加器的FEC信道编码方法研究。针对窄带电力线通信网络,给出了码距最大化的信道编码原则;可使用重复编码累加器来构造最大码距的信道编码,以提高比特能量噪声比;指出即使物理层无累加器,也可在数据链路层实现软累加器。设计信道编码比特累加器,使用大数判决方法进行纠错,并给出了累加器大数判决的信道误码性能及实际工程验证结果。研究了累加器与经典TS-ARQ算法的资源消耗,指出基于累加器的信道编码能够降低资源消耗,并能够获得更好的时间性能。根据信道质量间接估计的基本需求,研究用信道编码码距的反馈信息将信道质量划分为离散的区间,作为信道编码的参考;给出了算法并作了对比性研究,证明在满足可靠性前提下,信道质量反馈编码能够提高通信有效性。针对电力线通信网与外部网的接口,提出使用单芯片嵌入式TCP/IP协议栈来构造瘦服务器模式网关,给出网关参考模型和基本结构,研究和阐述CGI的接口方法,给出应用层实现的具体方法。针对重构算法和累加器信道编码的应用,研制实用的电力线扩频通信模块,并指出实际应用对扩频通信的限制。重点研究和开发电力线窄带通信模块,详细阐述了设计步骤,影响物理层性能的因素及相应的解决办法;给出了使用窄带电力线通信模块进行组网的方法以及在远程照明监控系统中应用的工程实例。电力线可重构算法以及基于累加器的自适应信道编码,受物理层限制较小,具有优良的通用性。单芯片电力线通信网关和电力线通信模块的设计方法,对研制可靠的电力线通信网络组件,具有较重要的参考价值;通过2年实际试验工程验证重构算法、信道编码、组网方法和电力线通信模块,适于大规模电力线通信网络的开发,并为更多领域应用奠定了基础。更多还原

【Abstract】 With the development of the broadband power line communication (PLC) access network, LAN and large scale monitoring and control network based on PLC, more and more reliability requirements, especially the connectivity of the network arises. The reliable data link is the key of the reliability problem in variable PLC channel. As previous documents and research achievements focus very little on the reliability of the PLC network, the main reasons that influence PLC network reliability is studied, and this work focus on the systematical methods and techniques that improve the reliability and effectivity of the PLC network theoretically and experimentally in practical engineering.Previous achievements including PLC channel input resistance, noise, reflection properties and channel model, are briefly discussed and summarized to extract the dynamic characters of the PLC channel. The existing achievements about the reliability of the PLC network are emphasized, present status of PLC research and applications are analyzed, and the most urgent problem, the reliability of PLC network is proposed for PLC network with a large scale of communication nodes.The OSI model and hierarchical classification method are applied in the research and the factor is pointed out that present PLC network is the lack of the interconnection function of Network Layer, which will affect the reliability of PLC network. It is very necessary to add Network Layer fuction in MAC layer, which could be accomplished with low cost and least hardware consumption. The reconfiguration property of PLC network is studied and the problem is pointed out that the reconfiguration in logic layer is the problem of initialization. The reconfiguration lemma is studied by step-by-step initialization strategy, and further the theorem is proposed and proved in x step strategy. Difference with common physical repeator network is distinguished and synchronization method is detailed. The reconfiguration algorithm is located at MAC layer with least physical layer affection, which is universally adaptive to most of the current PLC hardware platform.The topology after reconfiguration is studied further and a low cost TDMA- like protocol in MAC layer is also proposed for hybrid PLC network for the reliability of the data link, and M/D/1 model is utilized for the comparison with polling system and for the performance of the proposed protocol. The limitations in practical engineering to proposed algorithm are analized, and engineering algorithms that passed field test are given, as well as the general cycle time of the reconfigured PLC network that will be interested to remote supervisory applications.Aim to get universal adaptive to hardware platform as reconfiguration algorithm does, channel coding is utilized for error control to improve the communication reliability, and the basic principle of channel coding for the designing target of reliability is proposed. To increase signal-noise-ratio, the method that uses repeat-coding accumulator to construct channel coding is proposed. The soft accumulator can be realized in data link layer when no accumulators exist on physical layer.The channel coding bit accumulator is designed, majority judgment algorithm is proposed for error correction, and the performances of channel error rate with the majority judgment and accumulator together with the practical engineering field test results are detailed. The processor resource consumption for accumulator channel coding is studied comparing with classical TS-ARQ algorithm. This work points out that the channel coding with accumulator can reduce the processing resource consumption, and classical TS-ARQ algorithm is difficult to reach its theoretical performance due to the error rate of the preamble, and better performance of PLC network will be reached by channel coding with accumulator.The basic requirement of indirect channel evaluation is studied further, the method of utilizing channel code distance for discrete interval division of channel quality is proposed for channel coding reference, and the algorithm is given comparislly. The channel coding with feedback of channel quality can improve communication effectivity with satisfying the top aim of increasing reliability.Aim to interface PLC network with external network, this work proposed that embedded TCP/IP stack is suitable for the establishment of the gateway, and the reference model and basic structure of TCP/IP stack are addressed. The interface method with CGI is studied and discussed, and the details for the implementation of application layer are given.For the applications of reconfiguration algorithm and channel coding with accumulator, the spread spectrum based PLC module is designed with pointing out the limitation of PLC network applications. The research and development of narrow band PLC module is focused, designing strategies, the factors that affect physical layer performance and corresponding solutions are detailed. The networking methods and engineering example applied in lighting monitoring and control system based on narrow band PLC network is introduced.The proposed PLC network reconfigurable algorithm and channel coding based on accumulator with little limitation from physical layer, have excellent universal applicabilities. The design strategies of single-chip embedded PLC gateway and communication modules have important reference value for develop reliable PLC network components. The proposed reconfiguration algorithm, channel coding, networking strategy and designed PLC module, which are proofed by long-term engineering field test, can establish favorable foundation for the progress of PLC network with a large scale of nodes applied in more and more application fields.更多还原