LPLC信道检测与估计及其自适应速率传输研究与实现

发布时间：2018-10-08 17:58

【摘要】：低压电力线通信是指利用现有电力线网络实现数据传输的一种通信方式,具有线路投资小,连接方便等优点,应用前景广泛。随着通信技术及自适应技术的发展,低压电力线通信获得了飞速发展,同时朝着实用化方向前进,已成为当前科技领域的研究热点。但是,在380/220V低压电力线上进行信号通信,与高压电力线通信相比有其固有的不利特性,突出表现在信道环境恶劣且时变性大、负载多、线路阻抗小、信号衰减大、发送功率受限、噪声干扰严重等特点,设计一个适用于该信道环境的通信系统是目前低压电力线通信的关键难题。本课题针对低压电力线信道特性,研究相适应的关键通信技术,设计一种自适应速率传输系统来实现可靠、高效的通信。文章通过分析传统2FSK调制解调方法,利用谱估计和时频分析理论实现基于DSTFT解调的2FSK通信系统。根据低压电力线信道特性对通信系统的影响,研究信道估计方法,提出针对频域解调的基于DSTFT信噪比估计算法,为自适应速率传输系统中的数据最大比合并和等增益合并等方法提供解调参数,提高译码性能。自适应速率传输系统的设计主要包括CRC检错码、前向纠错码、HARQ技术、数据合并方法以及自适应速率同步调整算法等方面。同时,利用MATLAB搭建自适应速率传输系统模型,仿真分析系统性能。采用TI公司高性能32位定点DSP芯片TMS320F2812作为核心控制平台,软件编程实现LPLC自适应速率传输系统中各个模块的核心算法,包括2FSK调制模块、基于DSTFT的2FSK解调模块、串口收发模块、CRC检错码模块、汉明码编码与解码模块、HARQ反馈控制模块、数据合并模块和收发两端自适应速率同步调整模块等。并设计相应的外围电路,包括发送功放、耦合、谐振滤波和接收信号放大电路等,实现完整的点对点低压电力线通信系统。最后搭建低压电力线通信实验测试平台,通过不同的信道环境,分别测试与分析自适应速率传输系统在不同参数情况下的系统性能。实验结果表明,文章所设计的LPLC自适应速率传输系统可以有效提高通信系统的抗干扰能力,可以在恶劣的低压电力线信道环境下提高其通信可靠性。
[Abstract]:Low-voltage power line communication is a kind of communication mode which uses the existing power line network to realize data transmission. It has the advantages of low investment and convenient connection, and has a wide application prospect. With the development of communication technology and adaptive technology, low-voltage power line communication has been rapidly developed, and it has become a research hotspot in the field of science and technology. However, the signal communication on 380 / 220V low voltage power line has its inherent disadvantages compared with high voltage power line communication, which is characterized by bad channel environment, large time-varying, high load, low line impedance and large signal attenuation. With the characteristics of limited transmission power and serious noise interference, it is a key problem to design a communication system suitable for this channel environment. According to the characteristics of low voltage power line channel, this paper studies the key communication technology and designs an adaptive rate transmission system to realize reliable and efficient communication. By analyzing the traditional 2FSK modulation and demodulation methods, the 2FSK communication system based on DSTFT demodulation is realized by using spectrum estimation and time-frequency analysis theory. According to the influence of low voltage power line channel characteristics on the communication system, the channel estimation method is studied, and a DSTFT SNR estimation algorithm based on frequency domain demodulation is proposed. It can provide demodulation parameters for data maximum ratio combination and equal gain combination in adaptive rate transmission system, and improve decoding performance. The design of adaptive rate transmission system mainly includes CRC error detection code, forward error correction code HARQ technology, data merging method and adaptive rate synchronization adjustment algorithm. At the same time, the adaptive rate transmission system model is built with MATLAB, and the system performance is simulated and analyzed. The high performance 32-bit fixed-point DSP chip TMS320F2812 of TI is used as the core control platform. The core algorithm of each module in the LPLC adaptive rate transmission system is realized by software programming, including the 2FSK modulation module and the 2FSK demodulation module based on DSTFT. The serial transceiver module includes CRC error detection code module, hamming code coding and decoding module, HARQ feedback control module, data merging module and self-adaptive rate synchronous adjusting module. The corresponding peripheral circuits are designed, including transmission power amplifier, coupling, resonant filtering and receiving signal amplifying circuit, to realize a complete point-to-point low-voltage power line communication system. Finally, an experimental test platform for low-voltage power line communication is built to test and analyze the performance of the adaptive rate transmission system under different parameters through different channel environments. The experimental results show that the LPLC adaptive rate transmission system designed in this paper can effectively improve the anti-jamming ability of the communication system and improve its communication reliability under the bad low-voltage power line channel environment.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN913.6;TN911.23

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