【作者】 洪利；

【导师】 李树荣；

【作者基本信息】 中国石油大学 ， 控制理论与控制工程， 2010， 博士

【摘要】 电力线网络是世界上最为普遍也是覆盖最为宽广的一种网络。以低压电力线路作为传输通道的低压电力载波网络,直接利用已有的电力线资源,具有物理通道可靠性高、覆盖面广、使用方便、网络安装维护成本低、永久在线等优点。然而,由于缺乏能够适应现场实际的网络布局规划策略、可靠实时的介质访问控制协议和路由协议使得低压电力载波网络应用受到了制约。为了使低压电力载波网络能更加有效的得到应用,本文对低压电力载波网络介质访问控制、网络拓扑发现和分簇路由进行了研究,主要创新性工作如下:针对低压电力载波网络在节点规模大情况下传统介质访问控制协议网络的利用效率低和重传数据包实时性差等问题,提出有利于提高低压电力载波网络利用效率的基于工频同步的时隙介质访问控制协议。协议根据低压电力载波网络工频电压信号覆盖全网特点,采用交流电源工频(50Hz或60HZ)信号的过零信号对网络中所有的载波节点进行时钟同步。该协议通过优先级侦听、退避竞争、概率P预约告知等策略大大降低网络冲突概率,避免因大量数据包碰撞造成网络拥塞现象,提高了网络利用效率。采用固定竞争窗口和重传优先级提高机制保证重传数据的实时性。针对低压电力载波网络时变性造成难以进行有效的网络规划问题,提出可以准实时获取网络拓扑的基于最小信号衰减强度的拓扑发现算法。算法依据物理层信号强度及载波节点邻接关系建立电力载波网络最小生成树拓扑模型。采用遗传模拟退化算法进行拓扑发现,充分利用遗传算法加快收敛,模拟退火算法避免陷入局部最优,从而快速获得全网拓扑结构。针对该算法发现的拓扑链接数目较多,结构复杂问题,进一步引入度约束对算法进行改进,改进的算法获得的网络拓扑结构进一步简化,方便有效进行网络布局规划,进而提高网络可靠性。针对低压电力线载波网络普通分簇算法产生簇头过多、簇间路径单一问题,基于物理层接收信号强度提出了一种适应于低压电力载波网络的分簇算法及网络的重构方法。该算法采用衰减递减顺序角色确定法和簇间多路径分簇结构,有效地减少了簇头数量,降低了通信延迟,增加了簇间有效通信路径,提高了网络的可靠性。针对低压电力载波网络信道干扰与时变造成路由链路不可靠问题,在网络分簇的基础上提出一种具有可靠性保证的动态路由算法,该算法根据载波簇头网络拓扑为树状结构特点建立以最小传输延迟与丢包率为优化目标的算法模型算法,采用多路径的路由选择策略,避免最佳路径失效导致路由失败,提高网络的可靠性。为了提高路由搜索效率,采用遗传算法与蚁群算法相结合的寻优策略,结果表明结合算法比纯遗传算法和纯蚁群算法在平均时延、数据包投递成功率和网络吞吐量方面性能更优。更多还原

【Abstract】 Power line networks are the most widely used networks in the world. Low-voltage power line carrier networks utilize the existing power line resource without installing additional communication lines,which have the advantages of high reliability of physical access, wide coverage, convenience of application, low cost of network installation and maintenance, and always on line etc.. However, since the lack of network layout planning strategy to adapt to the actual site, reliable real-time medium access control and routing protocols, the wide application of the low-voltage power line carrier network is restrained currently. To make Low-voltage power line carrier networks work further effectively, this dissertation investigates the media access control, network topology discovery and clustered routing problems. The main contributions are listed as follows.For the low efficiency and poor real-time data packet retransmission in the case of large-scale nodes in traditional media access control protocol, a time-slot medium access control protocol based on power line frequency synchronization is obtained. According to the line-frequency signal covering the entire network, the protocol employs the AC power frequency (50Hz or 60HZ) zero-crossing signal to obtain clock synchronization of all carrier nodes to reduce network collision probability by Priority Sensing, competition withdrawing and probability p reservation notification. This protocol can avoid network congestion and ensure the real-time data in the retransmission through fixed competition windows and raising retransmission priority level mechanisms.For the difficulty of time-varying characteristics in network planning, a minimum signal strength attenuation based topology discovery algorithm is proposed. Firstly, a minimum spanning tree model in terms of the signal attenuation strength and adjacency relations between the nodes is established. Then a genetic simulated annealing based discovery algorithm is developed to find the high-performance topology in the whole network. The algorithm makes use of convergence acceleration of genetic algorithms and avoids local optimum of simulated annealing. But this algorithm may produce a number of topological links which may lead to complex structure. To improve this algorithm, a concept of degree-constrained is adopted to simplify the topology , achieve effective network planning and enhance network reliability.Regarding to a large number of the cluster heads and the only single path connected two clusters in the traditional cluster algorithm, a novel clustering algorithm and network reconfiguration method based on signal strenghth is presented, in which the attenuation descending order of signal strenghth and multi-path among the clusters is used. The results show that the number of the cluster heads and time delays is reduced, inter-cluster communication paths increased effectively and network reliability is enhenced.Aiming at the unreliable link proplem caused by channel interference and time-varying, a dynamic routing algorithm with reliability assurance based on clusters is given to achieve minimun transmission delay and packet loss rate, in which a multi-path routing strategy is used to avoid routing failures resulted from failure of the best path and improve network reliability. To enhance the efficiency of optimal routing search, a genetic and ant colony combined algorithm is provided. Compared with only genetic and only ant colony algorithm, the results show that the proposed algorithm can achieve the much better performance such as average time delay,Package delivery rate and network throughput .更多还原