Power Line Carrier Channel Estimation Orithm Based On Pilot Study

With the development of smart grid, smart home and the Internet of things, the development of power line communication (PLC) technology is growing rapidly, and it has become a hot research topic in recent years. PLC uses low voltage power line as communication medium to transmit data, voice and image, and existing cabling network can be used to improve the electric power communications industry with some good features, such as cost savings, easy access, wide coverage. However, due to different complexity between communication channel environments, low noise situations vary greatly and the reliability of PLC is threatened. In order to improve the quality of PLC, channel estimation (CE) of low voltage PLC is particularly important.CE technology gets the favour of the researchers, because its accuracy has a great influence on the reliability of PLC. The development of CE has experienced three stages:from no carrier diversity to inter-carrier diversity, from CE with single carrier to CE with multi-carrier, from a single time domain or single frequency domain to mixed estimation in time domain and frequency domain.In this paper, CE algorithm of PLC system based on the pilot channel is studied. First, characteristics of power line channel is analyzed, such as input impedance, Multi-path transmission and PLC signal attenuation, and power spectral density of background noise and impulse noise is simulated in MATLAB. In addition, the principle of the data transmission in low voltage power lines according to OFDM technology is discussed. CE algorithm based on the pilot channel which belongs to a non-blind CE algorithm is used in the research of PLC. It includes the selection and insertion of pilot pattern, and the insertion of intervals. LS algorithm, MMSE algorithm and LMMSE algorithm are simulated in MATLAB, and the relation between signal to noise ratio and bit error rate under three algorithms is contrasted. Based on LS algorithm, contrast of performance under different interpolating methods is studied. According to the simulation, the bit error rate under modified linear interpolation algorithm is found to be smaller. This paper provides a reference for the research of CE technology based on the pilot channel.