Research And Performance Analysis Of PLC Physical Layer Model Based On G3 Standard

Power line carrier communication(PLC)is a technology that uses the existing power line network as communication medium to realize information transmission.Compared with other communication technologies,it has many advantages,such as wide coverage of network,low cost of installation and maintenance,easy to monitor and manage.In recent years,the PLC technology played an irreplaceable role in the.fields of smart grid,smart home,intelligent energy and so on.However,the power line channel environment has the characteristics of complexity,variability and strong noise interference,which will seriously affect the communication quality of the system.Therefore,it is great practical significance and value to develop a reliable PLC technology.During the development of PLC technology,there have been formed some communication standards suitable for different environments.Among them,the G3-PLC standard is a narrowband power line carrier communication specification which defines physical layer and MAC level,and the complete signal frame structure in G3-PLC standard provides effective guarantee for reliable power line carrier communication.This thesis will study the key technology of power line carrier communication based on G3-PLC standard.The specific contents are as follows:1.The power line channel characteristics were studied theoretically,and a reliable channel model was established.According to the actual measurement noise of the domestic low-voltage power line channel,the characteristics of the power line noise of time and frequency domain has been analyzed,which provided a reliable basis for frequency selection in PLC system.2.Combined with the characteristics of power line channel,we have theoretically studied the OFDM technology in G3-PLC standard,physical layer model,signal frame structure,basic technical indicators and error control encoding technology,meanwhile analyzed and verified the anti-noise interference capability of G3-PLC standard in domestic low voltage power grid.3.This thesis proposed segment reconstruction coding technology based on G3-PLC standard.Aiming at the poor channel environment of domestic low-voltage power grid,this thesis made theoretical research on this technology in time domain,frequency domain and time-frequency domain respectively,which provided an effective and reliable solution to improve the anti-noise interference performance of PLC system.4.The experimental simulation platform of each algorithm was designed and established,and the simulation system was monitored and controlled by hybrid programming of Matlab and Lab View.Finally,a large number of experiments proved the anti-interference ability of the original G3-PLC system and the segmented reconstruction coding technology proposed in this thesis.The results showed that the original system could achieve reliable communication when the channel environment was good,but the communication quality was poor in a bad channel environment.In the measured power line noise channel,the time domain subsection reconstruction coding,the frequency domain subsection reconstruction coding and the time-frequency joint domain subsection reconstruction coding designed in this paper can achieve 2dB,4dB and 9dB performance boosting respectively compared with the original G3-PLC system when the bit error rate was 10-4.