Signal-to-noise ratio estimation method applicable to medium-voltage carrier system

Abstract

The invention particularly relates to a signal-to-noise ratio estimation method applicable to a medium-voltage carrier system, which comprises the following steps of: firstly, performing FFT on a timedomain sequence of a receiving end of the medium-voltage carrier system; then calculating first-order, second-order and fourth-order statistics through first Nt pieces of data; secondly, calculatinga threshold value with outlier removed based on the Pauta criterion and a statistics result, wherein the first Nt outliers do not need to be removed; combining each frame of data, performing outlier judgment on subsequent data, removing data which do not meet conditions; finally iteratively calculating non-average second-order and fourth-order statistic information, and introducing an intermediatevariable to simplify the calculation of a signal-to-noise ratio. According to the method, system adjustment is not needed, equalization is not needed, and the signal-to-noise ratio of each subcarriercan be accurately estimated through outlier elimination.

Description

technical field [0001] The invention belongs to the technical field of power line communication, and in particular relates to a signal-to-noise ratio estimation method suitable for a medium-voltage carrier system. Background technique [0002] With the continuous improvement of communication rate requirements, the power line communication system based on single carrier technology can no longer meet the current market demand. OFDM (Orthogonal Frequency Division Multiplexing, Orthogonal Frequency Division Multiplexing), as a multi-carrier modulation technology, is widely used in power line communication systems because of its high spectrum utilization efficiency and strong anti-multipath capability. However, the multi-carrier modulation technology will be affected by the selective fading of the channel, different noises of each frequency point, frequency offset, etc., and the difficulty of signal-to-noise ratio estimation is also greatly enhanced. Based on the characteristics ...

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Problems solved by technology

However, the multi-carrier modulation technology will be affected by the selective fading of the channel, different noises of each frequency point, frequency offset, etc., and the difficulty of signal-to-noise ratio estimation is also greatly enhanced. Based on the characteristics of OFDM, the present invention proposes a method suitable for medium-voltage carrier Systematic Subcarrier SNR Estimation Method

[0003] There are several methods for SNR estimation currently applied in the field of communication. One is the technology based on noise statistics, which is to estimate the noise power and signal power by capturing the noise information and the received signal information respectively, so as to calculate the signal-to-noise ratio. Noise ratio, the advantage of this method is that the signal-to-noise ratio estimation is relatively accurate, but it is greatly affected by frequency offset, and additional system overhead is required to capture noise; the other is the signal-to-noise ratio based on second-order statistics Ratio estimation technology, this method has limited SNR estimation performance, needs equalization processing, and will be affected by time variation; there is also a correlation processing based on pilot information, through the conversion of the relationship between correlation coefficient and SNR, it can be To realize the SNR estimation of the pilot, this method can only be used for the SNR estimation of the entire pilot, not for the SNR estimation of each subcarrier; there is also a SNR based on fourth-order statistics Estimation method, this method is very suitable for subcarrier signal-to-noise ratio estimation when frequency offset exists, but the existing method is greatly affected by time variation, and the estimation accuracy will be affected by the number of statistics, the two contradict each other, this paper The invention is the applicability improvement based on the estimation of the signal-to-noise ratio by the fourth-order statistics

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