CN112565147B - Signal-to-noise ratio estimation method suitable for medium-voltage carrier system - Google Patents

Signal-to-noise ratio estimation method suitable for medium-voltage carrier system Download PDF

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CN112565147B
CN112565147B CN202011337349.6A CN202011337349A CN112565147B CN 112565147 B CN112565147 B CN 112565147B CN 202011337349 A CN202011337349 A CN 202011337349A CN 112565147 B CN112565147 B CN 112565147B
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noise ratio
signal
frame
subcarrier
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CN112565147A (en
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徐剑英
李亮
王亚梁
王林涛
李铭贺
于洋
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Qingdao Topscomm Communication Co Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2655—Synchronisation arrangements
    • H04L27/2689—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation
    • H04L27/2695—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation with channel estimation, e.g. determination of delay spread, derivative or peak tracking
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2649—Demodulators
    • H04L27/265—Fourier transform demodulators, e.g. fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2655—Synchronisation arrangements
    • H04L27/2668—Details of algorithms
    • H04L27/2669—Details of algorithms characterised by the domain of operation
    • H04L27/2672—Frequency domain
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2655—Synchronisation arrangements
    • H04L27/2689—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation
    • H04L27/2692—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation with preamble design, i.e. with negotiation of the synchronisation sequence with transmitter or sequence linked to the algorithm used at the receiver

Abstract

The invention relates to a signal-to-noise ratio estimation method suitable for a medium-voltage carrier system
Figure DDA0002797651070000011
FFT is performed, then the first N is passedtCalculating first order, second order and fourth order statistics of each data, calculating a threshold value for outlier rejection based on the Lauda criterion and the statistic result, and defaulting to the top NtAnd combining the data of each frame without removing, judging the outlier of the subsequent data, removing the data which do not meet the conditions, iteratively calculating uneven second-order and fourth-order statistic information, and introducing an intermediate variable to simplify and calculate the signal-to-noise ratio. The invention does not need to carry out systematic adjustment and equalization, and can more accurately estimate the signal-to-noise ratio of each subcarrier by outlier elimination.

Description

Signal-to-noise ratio estimation method suitable for medium-voltage carrier system
Technical Field
The invention belongs to the technical field of power line communication, and particularly relates to a signal-to-noise ratio estimation method suitable for a medium-voltage carrier system.
Background
With the increasing demand of communication rate, the power line communication system based on single carrier technology cannot meet the current market demand. OFDM (Orthogonal Frequency Division Multiplexing) is a multi-carrier modulation technique, and is widely used in power line communication systems due to its advantages such as high spectrum utilization efficiency and strong multipath resistance. However, the multi-carrier modulation technology can be influenced by selective fading of a channel, different noise of each frequency point, frequency offset and the like, and the difficulty of signal-to-noise ratio estimation is greatly enhanced.
The signal-to-noise ratio estimation method applied to the communication field at present comprises the following methods, one is a technology based on noise statistics, namely noise power and signal power are estimated by respectively capturing noise information and received signal information, so as to calculate the signal-to-noise ratio, and the method has the advantages that the signal-to-noise ratio estimation is relatively accurate, but is greatly influenced by frequency offset, and meanwhile, extra system overhead is required to be added for capturing noise; the other is a signal-to-noise ratio estimation technology based on second-order statistics, and the signal-to-noise ratio estimation performance of the method is limited, needs equalization processing and can be influenced by time variation; the other method is based on the correlation processing of pilot frequency information, and can realize the signal-to-noise ratio estimation of the pilot frequency through the relation conversion of the correlation coefficient and the signal-to-noise ratio, and the method can only be used for the signal-to-noise ratio estimation of the whole pilot frequency and is not suitable for the signal-to-noise ratio estimation of each subcarrier; the other is a signal-to-noise ratio estimation method based on the fourth order statistic, which can be well applied to the subcarrier signal-to-noise ratio estimation in the presence of frequency offset, but the existing method is greatly influenced by time variation, the estimation precision is influenced by the statistic number, and the two are contradictory to each other.
Disclosure of Invention
In order to solve the defects of the prior art, the invention provides a signal-to-noise ratio estimation method suitable for a medium-voltage carrier system, which is used for accumulating and rejecting outliers of subcarrier information of different frames on the basis of a four-order statistic signal-to-noise ratio estimation method to realize the signal-to-noise ratio estimation of each subcarrier, thereby not only being suitable for the influence of frequency deviation and phase change of different frame information, but also being capable of more accurately estimating the signal-to-noise ratio of each subcarrier on the basis of not introducing extra system overhead.
In order to achieve the above object, the present invention provides a signal-to-noise ratio estimation method suitable for a medium voltage carrier system, and the technical scheme of the present invention is as follows:
a signal-to-noise ratio estimation method suitable for a medium-voltage carrier system comprises the following steps:
step 1: firstly, the time domain sequence of the receiving end is sequenced
Figure BDA0002797651050000011
FFT (Fast Fourier transform) was performedmatrix, fast fourier transform), where i represents the frame number, l represents the l-th pilot group, n represents the n-th sampling point, and the frequency domain sequence Y of each subcarrier corresponding to the pilot position and the frequency point position is selectedl i(k) K represents the k-th subcarrier, and N is the total number of subcarriers.
The medium-voltage carrier system adopts a comb-shaped pilot frequency arrangement mode, and the pilot frequency is fixed, so that the medium-voltage carrier system can be used for estimating the signal-to-noise ratio.
Step 2: then using the respective subcarrier wave front NtCounting the first, second and fourth order statistics of each data, and calculating the first NtCalculating the elimination threshold of each data, and defaulting to the top NtEach data is data satisfying a threshold condition, NtIs generally 5-20, i.e. counting from the 1 st frame data, when the number of sub-carriers reaches NtWhen the frequency domain sequence at this time can be expressed as
Figure BDA0002797651050000021
If the first frame data can not satisfy NtIf the number of the first frame is equal to N, merging the data of the second frame until the count reaches NtThen, the first, second and fourth order statistics are calculated, respectively
Figure BDA0002797651050000022
Figure BDA0002797651050000023
Figure BDA0002797651050000024
And step 3: based on the Lauda criterion, calculating a threshold Th (k) of a k-th subcarrier rejection field value according to first-order, second-order and fourth-order statistics, wherein the threshold is 3 times of standard deviation sigma (k), namely
Figure BDA0002797651050000025
And 4, step 4: and combining the data of each frame, and removing the subsequent subcarrier data which do not meet the threshold condition, wherein the removal principle is as follows:
if Yl i(k)-M1(k) If | Th (k), the suspect value Yl i(k) Contains gross errors and needs to be discarded, otherwise, the gross errors are retained.
And 5: counting each sub-carrier data after eliminating the judgment wild value of each frame by adopting a real-time iterative processing mode, and assuming that the current count of the kth sub-carrier is tkSeparately calculating the second and fourth order statistics of the mean, i.e.
Figure BDA0002797651050000026
Figure BDA0002797651050000027
Wherein the content of the first and second substances,
Figure BDA0002797651050000028
when t isk＜NtAnd when the data is not rejected, the data is not rejected.
Step 6: when the count of all sub-carriers reaches the set number NsThen, the data of the frame at this time outputs the result of the signal-to-noise ratio, and the count of each subcarrier is the number T of the frame after all data are eliminatedkAt this time Tk≥NsAfter the calculation counting is finished, the signal-to-noise ratio is calculated, and the calculation formula of the k sub-carrier signal-to-noise ratio is shown as follows
Figure BDA0002797651050000029
Wherein the content of the first and second substances,
Figure BDA00027976510500000210
the final computational complexity can be reduced by simplifying the formula.
Further, N is set as described in step 6sThe number is 200.
The invention has the beneficial effects that: 1. the signal-to-noise ratio can be estimated more accurately without system adjustment and equalization. 2. The method adds outlier removal and real-time statistic calculation, thereby greatly reducing the complexity problem caused by the four-order statistic. 3. The method for estimating the signal-to-noise ratio of the subcarrier is combined with the comb-shaped arrangement based on the pilot frequency of the medium-voltage carrier, is not influenced by frequency offset and phase rotation, can combine multi-frame data, and greatly improves the estimation accuracy.
Drawings
Fig. 1 is a flowchart of the snr estimation method of the present invention for a medium voltage carrier system.
Fig. 2 shows the arrangement of the pilot and sub-carriers of the ballast system of the present invention.
Fig. 3 is a RMSE of the snr of the first subcarrier as a function of the data amount of the subcarrier suitable for the snr estimation method of the medium voltage carrier system.
Fig. 4 is a graph of RMSE versus signal-to-noise ratio variation for the signal-to-noise ratio of the first subcarrier suitable for the signal-to-noise ratio estimation method of the medium voltage carrier system.
Fig. 5 is a RMSE versus frequency offset variation for the snr of the first subcarrier suitable for the snr estimation method of the medium voltage carrier system.
Detailed Description
The technical solution in the embodiments of the present invention is clearly and completely described below with reference to the drawings in the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, the technical scheme of the invention comprises the following specific steps:
step 1: firstly, the time domain sequence of the receiving end is sequenced
Figure BDA0002797651050000031
Performing Fast Fourier Transform (FFT), wherein i represents a frame number, l represents the l-th pilot frequency group, and n represents the n-th sampling point, and selecting the frequency domain sequence Y of each subcarrier corresponding to the pilot frequency position and the frequency point positionl i(k) And k represents the kth subcarrier, and N is the total number of subcarriers. As shown in fig. 2, the medium-voltage carrier system adopts a comb-shaped pilot arrangement, and the pilot is fixed, so that the pilot can be used for estimating the snr.
Step 2: next will be NtCalculating the elimination threshold of each data, and defaulting to the top NtAll the data are data satisfying the threshold condition, and in the concrete implementation, N is assumedt10, i.e. counting from frame 1 data, when the number of sub-carriers reaches NtWhen the frequency domain sequence at this time can be expressed as
Figure BDA0002797651050000032
If the first frame data can not satisfy NtIf the number of the first frame is equal to N, merging the data of the second frame until the count reaches NtThen, the first, second and fourth order statistics are calculated, respectively
Figure BDA0002797651050000033
Figure BDA0002797651050000034
Figure BDA0002797651050000035
And step 3: based on the Lauda criterion, calculating a threshold Th (k) of a k-th subcarrier rejection field value according to first-order, second-order and fourth-order statistics, wherein the threshold is 3 times of standard deviation sigma (k), namely
Figure BDA0002797651050000041
And 4, step 4: merging the data of each frame, and removing the sub-carrier data which do not meet the threshold condition, wherein the removing principle is as follows,
if Yl i(k)-M1(k) If | Th (k), the suspect value Yl i(k) Contains gross errors and needs to be discarded, otherwise, the gross errors are retained.
And 5: counting each sub-carrier data after eliminating the judgment wild value of each frame by adopting a real-time iterative processing mode, and assuming that the current count of the kth sub-carrier is tkSeparately calculating the second and fourth order statistics of the mean, i.e.
Figure BDA0002797651050000042
Figure BDA0002797651050000043
Wherein the content of the first and second substances,
Figure BDA0002797651050000044
when t isk＜NtAnd when the data is not rejected, the data is not rejected.
Step 6: when the count of all sub-carriers reaches the set number NsThen, the data of the frame at this time outputs the result of the signal-to-noise ratio, and the count of each subcarrier is the number T of the frame after all data are eliminatedkAt this time Tk≥NsAfter the calculation counting is finished, the signal-to-noise ratio is calculated, and the calculation formula of the k sub-carrier signal-to-noise ratio is shown as follows
Figure BDA0002797651050000045
Wherein the content of the first and second substances,
Figure BDA0002797651050000046
in order to verify the performance of the present invention, as shown in fig. 3, when the snr is 10dB, it can be seen from the relationship curve that the RMSE estimated by the snr of the first subcarrier varies with the data amount of the subcarrier, that the larger the data amount of the current subcarrier is, the more accurate the estimation is, and in the specific implementation, N is sets200 parts of a total weight; as shown in FIG. 4, NsWhen the signal-to-noise ratio is 200, it can be seen from a relation curve of RMSE estimated by the signal-to-noise ratio of the first subcarrier, that the smaller the signal-to-noise ratio, the more inaccurate the estimation is; as shown in FIG. 5, NsWhen the signal-to-noise ratio is 10dB, it can be seen from the relationship curve of RMSE estimated by the signal-to-noise ratio of the first subcarrier as a function of the frequency offset that the frequency offset has no influence on the present invention.
Finally, it should be noted that: the above embodiments are only intended to illustrate the technical solution of the present invention and not to limit the same, and a person of ordinary skill in the art can make modifications or equivalents to the specific embodiments of the present invention with reference to the above embodiments, and such modifications or equivalents without departing from the spirit and scope of the present invention are within the scope of the claims of the present invention as set forth in the claims.

Claims (2)

1. A signal-to-noise ratio estimation method suitable for a medium-voltage carrier system is characterized by comprising the following steps:
step 1: firstly, the time domain sequence of the receiving end is sequenced
Figure FDA0003507871870000011
Performing Fast Fourier Transform (FFT), wherein i represents a frame number, l represents the l-th pilot frequency group, and n represents the n-th sampling point, and selecting the frequency domain sequence Y of each subcarrier corresponding to the pilot frequency position and the frequency point positionl i(k) K represents the kth subcarrier, and N is the total number of subcarriers;
step 2: next will be NtNumber ofAccording to the calculation of the elimination threshold value, the top N is defaultedtEach data is data satisfying a threshold condition, NtIs 5-20, namely counting from the 1 st frame data, when the number of sub-carriers reaches NtThe frequency domain sequence at this time is represented as
Figure FDA0003507871870000012
If the first frame data can not satisfy NtIf the number of the first frame is equal to N, merging the data of the second frame until the count reaches NtThen, the first, second and fourth order statistics are calculated, respectively
Figure FDA0003507871870000013
Figure FDA0003507871870000014
Figure FDA0003507871870000015
And step 3: based on the Lauda criterion, calculating a threshold Th (k) of a k-th subcarrier rejection field value according to first-order, second-order and fourth-order statistics, wherein the threshold is 3 times of standard deviation sigma (k), namely
Figure FDA0003507871870000016
And 4, step 4: and combining the data of each frame, and removing the subsequent subcarrier data which do not meet the threshold condition, wherein the removal principle is as follows:
if Yl i(k)-M1(k) If | Th (k), the suspect value Yl i(k) Containing gross errors, the error is discarded, and the error is retained in other cases;
and 5: counting each sub-carrier data after eliminating the judgment wild value of each frame by adopting a real-time iterative processing mode, and assuming that the current count of the kth sub-carrier is tkSeparately calculating the second and fourth order statistics of the mean, i.e.
Figure FDA0003507871870000017
Figure FDA0003507871870000018
Wherein the content of the first and second substances,
Figure FDA0003507871870000019
when t isk＜NtWhen the data is not rejected, the data is not rejected;
step 6: when the count of all sub-carriers reaches the set number NsThen, the data of the frame at this time outputs the result of the signal-to-noise ratio, and the count of each subcarrier is the number T of the frame after all data are eliminatedkAt this time Tk≥NsAfter the calculation counting is finished, the signal-to-noise ratio is calculated, and the calculation formula of the k sub-carrier signal-to-noise ratio is shown as follows
Figure FDA0003507871870000021
Wherein the content of the first and second substances,
Figure FDA0003507871870000022
the final computational complexity can be reduced by simplifying the formula.
2. The method as claimed in claim 1, wherein the set N is N in step 6sThe number is 200.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7496164B1 (en) * 2003-05-02 2009-02-24 At&T Mobility Ii Llc Systems and methods for interference cancellation in a radio receiver system
CN101616120A (en) * 2009-07-28 2009-12-30 北京大学 One signal-to-noise ratio of subcarrier method of estimation and system
CN110336647A (en) * 2019-08-15 2019-10-15 深圳市烽云技术有限公司 A kind of wireless self-networking Adaptive Anti-jamming dispatching method and device

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7835454B2 (en) * 2004-04-30 2010-11-16 Analog Devices, B.V. Multicarrier modulation systems

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7496164B1 (en) * 2003-05-02 2009-02-24 At&T Mobility Ii Llc Systems and methods for interference cancellation in a radio receiver system
CN101616120A (en) * 2009-07-28 2009-12-30 北京大学 One signal-to-noise ratio of subcarrier method of estimation and system
CN110336647A (en) * 2019-08-15 2019-10-15 深圳市烽云技术有限公司 A kind of wireless self-networking Adaptive Anti-jamming dispatching method and device

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
一种高动态低信噪比下载波快速捕获跟踪方法;段旭等;《飞行器测控学报》;20140331;第33卷(第2期);全文 *
基于高阶累积量的OFDM信号调制识别技术;李彦栓等;《电子信息对抗技术》;20120731;第27卷(第4期);全文 *

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