The Research Of Power Line High-speed Data Communication Based On Adaptive OFDM

Low voltage power line communication as the data transmission media,network coverage is very wide, and the cost is low, the connection is convenient,is an increasingly active in the line of sight of people of a new type ofcommunication. Generally take their modulation technique is an orthogonalfrequency division multiplexing, which is a multi-carrier modulation. On thebasis of the Universal Powerline multipath model, using the modulationtechnique can effectively overcome multipath interference andfrequency-selective fading disadvantage, effectively improve the spectrumutilization. Adaptive OFDM technique according to each user subcarriers SNR,dynamically the number of bits and transmission power allocation to each user ineach sub-carrier and subcarrier, can effectively reduce the effects of poor channelcharacteristics of data transmission.To different locations, in the range of0.5Hz~20MHz, different power linetransmission characteristics for multipath propagation model structure of theactual low pressure carrier communication channel is measured based on existingpower lines, the data as a sample. The standard PSO algorithm and AFSAcombine path parameter identification, parameter setting becomes easy tounderstand and improve the accuracy of finding the optimal solution, theparameters become concentrated, and shorten the identification time.For multi-user OFDM system, due to channel and bit and power allocationalgorithm iteration complex, although the use of packet allocation methodreduces the computational complexity, but the system performance degradation.In this paper, in order to optimize the premise, hybrid particle swarmoptimization algorithm is improved fish, combined with channel allocation and bit allocation issue and realize power allocation in multiuser OFDM adaptivepower line environment, so as to transmit power reduction, and save computationtime, improve spectrum utilization.In order to validate the use of hybrid fish PSO algorithm to optimize thedegree of optimization of the power line model, to build a hardware and softwareintegration test simulation platform, simulated by each base unit. Analog powerline channel with the platform’s features, its topology is realized throughcomputer control relay, the user can be obtained according to the actual needs ofdifferent channel simulation environment. Provides an experimental platform forlow-voltage power line carrier communication technology workers expect to be aflexible and practical tools.