电力线载波通信多信道访问机制与混合通信机理研究

发布时间：2018-09-14 09:09

【摘要】：低压电力线载波通信存在网络拓扑复杂多变,通信环境恶劣等问题,导致电力线通信可靠性低,通信距离有限,限制了电力线载波通信技术的规模化发展。本文从提高电力线通信可靠性和增加通信范围的角度出发,对低压电力线载波通信的介质访问控制协议以及跨频带通信进行研究。本文首先分析了电力线通信技术的总体研究现状,分别对窄带通信和宽带通信的协议与标准进行总结归纳,在比较和讨论了各通信标准中介质访问控制协议的基础上,提出目前协议中存在的问题。其次,对低压电力线传输特性进行研究,从低压电力线网络结构和传输特性两个方面对电力线频率衰减效应、多径效应以及噪声特性进行建模仿真分析,并结合相关实测数据,探讨跨频带通信的可能性,设计一种跨频带通信系统,打破传统电力线载波通信技术中宽带通信与窄带通信的束缚。然后,研究现有的低压电力线介质访问控制协议,建模仿真总结各协议的优势与不足,在此基础上,提出适用于大规模电力线网络的新型介质访问控制协议设计要求,其特点是能够适应大规模网络应用,在网络规模不断扩大的情况下,仍能保持较高的传输效率,保证网络吞吐量同时能在一定程度上解决暴露终端和隐终端问题。再次,设计一种基于时间片的介质访问控制协议,采用周期访问机制、优先级区分机制以及退避竞争等手段有效降低节点之间冲突概率,保证网络的传输效率。利用MATLAB软件搭建仿真模型,对现有的介质访问协议和本文提出的新协议进行仿真对比验证,结果表明,在大规模网络条件下,本文提出的新型介质访问控制协议稳定性更强,传输效率更高。最后,本文设计一种基于等效复数基带和收发端加窗的数字前端,以实现跨频带通信,同时设计一种基于前导序列的频率识别方法,以实现电力线通信节点的信道认知和频率选择。利用OMNe T++仿真平台搭建仿真模型,对多频通信进行仿真验证,仿真结果表明采用多频通信,网络节点接入率和接入速度明显提高,对提高电力线载波通信可靠性具有重要意义。
[Abstract]:Low voltage power line carrier communication has many problems, such as complex network topology and bad communication environment, which leads to low reliability and limited communication distance, which limits the large-scale development of power line carrier communication technology. From the point of view of improving the reliability of power line communication and increasing the communication range, this paper studies the medium access control protocol and cross-band communication for low-voltage power line carrier communication. Firstly, this paper analyzes the general research status of power line communication technology, summarizes the protocols and standards of narrowband communication and broadband communication, and compares and discusses the media access control protocols in each communication standard. The problems existing in the present protocol are put forward. Secondly, the transmission characteristics of low voltage power line are studied. The power line frequency attenuation effect, multipath effect and noise characteristics are modeled and simulated from the aspects of low voltage power line network structure and transmission characteristics. This paper discusses the possibility of cross-band communication, designs a cross-band communication system, and breaks the shackles of broadband and narrow-band communication in traditional power line carrier communication technology. Then, the existing low-voltage power line media access control protocol is studied, and the advantages and disadvantages of each protocol are summarized by modeling and simulation. On this basis, the design requirements of a new medium access control protocol suitable for large-scale power line networks are put forward. Its characteristics are that it can adapt to large scale network applications, maintain high transmission efficiency and ensure network throughput to solve the problem of exposed terminals and hidden terminals to a certain extent while the network scale is expanding. Thirdly, a media access control protocol based on time slice is designed, which uses periodic access mechanism, priority differentiation mechanism and Backoff competition to effectively reduce the probability of conflict between nodes and ensure the transmission efficiency of the network. The simulation model is built by using MATLAB software. The simulation results show that the new media access control protocol proposed in this paper is more stable under the condition of large-scale network. Transmission efficiency is higher. Finally, a digital front end based on equivalent complex baseband and windowed transceiver is designed to realize cross-band communication, and a frequency recognition method based on leading sequence is designed. In order to realize the power line communication node channel recognition and frequency selection. OMNe T simulation platform is used to build simulation model to verify the multi-frequency communication. The simulation results show that the network node access rate and access speed are improved obviously by using multi-frequency communication. It is of great significance to improve the reliability of power line carrier communication.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN913.6

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