Design Of Low-voltage Power Line Carrier Communication Module Based On OFDM

Power line carrier communication is a way of data transmission based onpower lines as a transmission medium. With the progressing of modulation anddemodulation technology, data transmission speed has been significantlyincreased. This communication technology become the indoor network solutiontogether with Ethernet and wireless LAN,which has complement each other. Ithas some advantage, like no wiring, covering a wide range, and setting up easily.After2000, power line communication technology based on power lines has beena major improvement, it uses orthogonal frequency division multiplexing to dothe demodulation of the modulation of signal, this pattern uses the multiplemutually orthogonal sub-carriers to transmit signals. And therefore comparedwith the traditional communication mode, spread spectrum, the spectrumutilization factor is improved.Firstly, the channel analysis of the low-voltage power line transmissionmedium is carried out to study the channel characteristics, like the transmissionline interference, input impedance, channel noise and channel attenuation.Modem technology determines the transmission rate, transmission distance andsignal interference. This paper introduces two patterns of signal modulation anddemodulation: spread spectrum and orthogonal frequency division multiplexing.This paper focuses on orthogonal frequency division multiplexing pattern, andelaborates the principles and advantages and disadvantages of this technology.Then this dissertation designs the power line carrier communication modulebased on the study on the orthogonal frequency division multiplexing pattern,which is divided into the following several parts: the core unit selects Intellon’sINT5500for signal modulation and demodulation. INT1200for signals’ DAC and ADC conversion. Ethernet part selects the Ethernet controller chip,IP101ALF, main function is to implement the transformation of data framestructure between Ethernet and Power gird. Power part selects TNY264switching power supply chip to realize the various types of voltage outputrequired by the module. And there are signal coupling part, the signaltransmitting and receiving parts and so on.Finally, this dissertation takes a test for the module, confirms that the modulecan realize the transmission of signals between Ethernet and Power grid,orthogonal frequency division multiplexing technology in low voltage power linetransmission has a good application prospect and practical value.