OFDM电力线通信方法研究及DSP实现

发布时间：2018-11-28 09:26

【摘要】：电力线通信是指以现有的中、低压电力线配电网络作为传输媒介,实现数据、图像、语音等综合业务传输的通信技术。电力线载波通信技术利用现有电力线网络,具有布署快速,无需额外布线,覆盖范围广等优点,应用前景十分广阔。但是,电力线网络是专门为输电要求配置的,有其固有的不利特性,故需要采用合适的调制解调技术,才能克服电力线上的干扰和衰耗,实现电力线上的可靠传输通信。基于电力线通信环境的特点以及传输特性,对比研究现在电力线载波通信技术之间的优劣后,本课题决定采用正交频分复用调制技术以实现电力线上的载波通信。正交频分复用(OFDM)技术具有抗干扰能力强、频谱利用率高、可以用IFFT/FFT实现调制解调等优点,因此在电力线载波通信领域得到了越来越广泛的应用。然而,OFDM技术也存在一些缺点：较高的峰值平均功率比(PAPR)、对接收端同步系统性能要求较为苛刻等。本文正是研究基于OFDM技术的低压电力线通信技术,并采用DSP芯片实现能够在低压电力线环境下进行数据发送与接收的OFDM通信系统。本文首先针对国内的电力线噪声环境,对低压电力线信道的噪声特性进行了分析,从系统实际应用、测试的环境、现有的硬件情况出发,建立能满足电力线信道环境的通信模型,并分析了电力线信道的固有特性,为研究电力线信道对通信系统性能的影响提供了理论依据。接着,本文对降低OFDM系统的峰均比和同步这两个关键技术进行了部分介绍与研究。本文对比了几种常见的降低OFDM系统峰均比的方法。之后,对OFDM系统的同步技术进行了研究,并研究一种适合在电力线通信系统上发送突发数据的同步算法。在该算法中,对前导符号中的同步帧进行了设计,以便接收端利用这些前导符号的长短训练序列来达到快速同步的效果,并用MATLAB软件对该算法进行仿真。最后,本文设计了一个适合在电力线上通信的完整的OFDM系统方案。介绍了该系统发送端各个功能模块的设计以及接收端中由DSP完成的功能模块的设计,并用MATLAB软件对各个功能模块进行仿真分析,再对整个系统的误码率性能进行仿真,验证了系统的实用性。之后采用TI公司的DSP芯片TMS320VC5416作为核心控制平台,编程实现以上功能模块的设计,并进行测试。测试结果表明该系统设计符合预期的性能。
[Abstract]:Power line communication is a kind of communication technology, which uses the existing medium, low voltage power line distribution network as the transmission medium to realize the data, image, voice and other integrated services transmission. Power line carrier communication technology makes use of the existing power line network, which has the advantages of fast deployment, no extra wiring, wide coverage and so on. However, the power line network is specially configured for transmission requirements, which has its inherent disadvantages, so it is necessary to adopt appropriate modulation and demodulation technology in order to overcome the interference and decay on the power line and to realize reliable transmission and communication on the power line. Based on the characteristics of power line communication environment and transmission characteristics, after comparing the advantages and disadvantages of the current power line carrier communication technology, this subject decided to adopt orthogonal frequency division multiplexing modulation technology to realize the carrier communication on the power line. Orthogonal Frequency Division Multiplexing (OFDM) has been widely used in power line carrier communication field because of its strong anti-jamming ability, high spectral efficiency and the ability to realize modulation and demodulation with IFFT/FFT. However, OFDM technology also has some disadvantages: the higher peak average power is more demanding than the (PAPR), on the performance of the receiver synchronization system, and so on. This paper studies the low-voltage power line communication technology based on OFDM technology, and uses DSP chip to realize the OFDM communication system which can transmit and receive data under the low-voltage power line environment. In this paper, the noise characteristics of the low-voltage power line channel are analyzed in the light of the domestic power line noise environment. The actual application of the system, the testing environment and the existing hardware situation are discussed. A communication model which can satisfy the power line channel environment is established, and the inherent characteristics of the power line channel are analyzed, which provides a theoretical basis for studying the influence of the power line channel on the performance of the communication system. Then, the two key technologies of reducing PAPR and synchronization of OFDM system are introduced and studied in this paper. In this paper, several common methods to reduce PAPR in OFDM system are compared. Then, the synchronization technology of OFDM system is studied, and a synchronization algorithm suitable for transmitting burst data on power line communication system is studied. In this algorithm, the synchronization frame in the preamble is designed so that the receiver can use the training sequence of the preamble to achieve the effect of fast synchronization. The algorithm is simulated by MATLAB software. Finally, a complete OFDM system scheme is designed for power line communication. This paper introduces the design of each function module in the transmitter and the design of the function module completed by DSP in the receiving end of the system. The simulation analysis of each function module is carried out with the MATLAB software, and the BER performance of the whole system is simulated. The practicability of the system is verified. Then the DSP chip TMS320VC5416 of TI Company is used as the core control platform, and the design of the above function module is realized by programming, and the test is carried out. The test results show that the system design meets the expected performance.
【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

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