Research On Key Technologies Of Low Voltage Power Line Carrier Communication

Power line communication(PLC)is a way of communication which uses power line as a instrumentality to transmitter data.Because it has lots of advantages,for example,low cost,easy to use and simple equipment,it has attracted much attention.With the continuous development of domestic smart grid construction and the growing demand for broadband,power line carrier communication is developing rapidly in the direction of high speed and broadband.In this context,this paper studies the key technologies of low-voltage power line carrier communication,analyzes the problems encountered,and gives the corresponding solutions.Specifically,the main contents are as follows:(1)The main characteristics of power line channel are analyzed in detail,including noise characteristics,impedance characteristics and attenuation characteristics.Based on previous work,the noise model and channel model of power line channel are established,and the simulation is carried out at the same time,which provides a reliable channel model for PLC system simulation.(2)Taking the State Grid protocol as a reference,the power line carrier communication system based on OFDM technology is deeply studied.Firstly,the principle and system model of OFDM are described in detail.Secondly,the key technologies of OFDM transmitter are introduced,including channel coding,channel interleaving,diversity copy,constellation mapping,IFFT and preamble.Then,the key technologies are implemented by FPGA,and the corresponding hardware design schematic diagram and design method are given.Finally,the simulation is carried out one by one.(3)In order to solve the synchronization problem of OFDM system,the common synchronization algorithm is discussed.After analyzing and comparing their advantages and disadvantages,the FPGA code design is carried out by selecting the delay correlation algorithm with better performance and improved local training cross correlation algorithm,and the simulation verification is carried out.(4)The principle of channel estimation in power line carrier communication system is deeply studied,and the advantages and disadvantages of traditional channel estimation algorithms are discussed.At the same time,orthogonal matching pursuit(OMP)algorithm,which is widely used in compressed sensing,is applied to channel estimation,and the two algorithms are compared and analyzed.In addition,on the basis of OMP algorithm,an OMP channel estimation algorithm based on noise preprocessing is proposed.The main purpose of this algorithm is to suppress the channel noise by various means before the OMP compressed sensing channel estimation,so as to achieve the purpose of reducing the system error rate.Simulation results show that the performance of this algorithm is better than that of OMP algorithm without processing.There are 74 pictures,11 tables and 80 references in this paper.