CN108933751B - Detection-based OFDM signal gain control method, device and recording medium - Google Patents

Detection-based OFDM signal gain control method, device and recording medium Download PDF

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CN108933751B
CN108933751B CN201810632661.4A CN201810632661A CN108933751B CN 108933751 B CN108933751 B CN 108933751B CN 201810632661 A CN201810632661 A CN 201810632661A CN 108933751 B CN108933751 B CN 108933751B
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ofdm
ofdm signal
detection
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CN108933751A (en
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付林罡
闫朝星
孙亚男
李辉
焦东立
彭浪
胡学明
李旭鹏
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Beijing Research Institute of Telemetry
Aerospace Long March Launch Vehicle Technology Co Ltd
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Aerospace Long March Launch Vehicle Technology 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
    • H04L27/2692—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
    • 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
    • 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

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Abstract

The OFDM signal gain control method based on detection comprises the following steps: step one, based on preset initial gain control parameters and OFDM signal second orderMoment signal power estimation calculation gain controlled error tracking signal EA1While detecting preamble symbol data y of the OFDM signalP(n) and a received signal y (n); step two, according to the OFDM signal leading symbol data y obtained in the step oneP(n) calculating an error tracking signal E for time-domain gain controlA2(ii) a Step three, calculating an error tracking signal E of frequency domain gain control according to the received signal y (n) obtained in the step oneA3。

Description

Detection-based OFDM signal gain control method, device and recording medium
Technical Field
The invention relates to an OFDM signal gain control method based on detection, a device and a recording medium, belonging to the technical field of digital wireless communication transmission.
Background
In an aircraft measurement and Control communication system, the relative position relationship between airborne communication terminals and between the airborne communication terminals and a ground Control station in the navigation process has a dynamic change characteristic, the general measurement and Control communication system is difficult to adjust the transmitting power through power Control to realize stable signal reception, and the large dynamic range reception of the received signals is usually realized on one side of a receiver through Automatic Gain Control (AGC). Especially in a high-speed data transmission unmanned aerial vehicle data chain system based on a TDD single-duplex mode of burst transmission, the gain control of a received signal needs to be completed quickly and accurately, and the validity of analog-to-digital conversion ADC inlet data is ensured.
Meanwhile, in order to effectively combat multipath interference in a low elevation angle environment, the high-speed data chain system mainly adopts an Orthogonal Frequency Division Multiplexing (OFDM) system. The OFDM signal has a large dynamic range in the time domain, which makes it challenging for a receiver to perform fast and accurate gain control. For new application fields such as a mobile communication system adopting an OFDM system or an unmanned aerial vehicle data link system, ADI corporation develops a transceiver architecture based on a software radio platform, typically AD9361, AD9371, AD9375 platform, and the like. The transceivers are integrated with a gain control module, and mainly have two modes of automatic gain control AGC and manual gain control MGC. The automatic gain control mode does not need the baseband processing BBP of the FPGA to carry out interactive control, and the manual gain control MGC mainly controls a pointer pointing to a gain lookup table, and the lookup table is divided into a full table mode and a sub-table mode. Each receiver in the full table mode controls the gain by a pointer, and the baseband processing BBP in the sub-table mode controls the gains of the LMT (low noise amplifier LNA, mixer and transimpedance amplifier) and the low pass filter LPF, respectively. The lookup table generally performs AGC stepping with 1dB as a unit, and in a manual gain control MGC mode, there are two gain control methods for BBP: the gain pointer is controlled using an SPI write, or moved using a "control in" pin. The automatic gain control processes the amplitude of the received signal based on the total energy of the received signal and noise, and the manual gain control MGC mode needs to effectively scale the amplitude of the received signal in the baseband processing BBP, which is similar to the conventional automatic gain control circuit, and for example, the gain control processing is needed in the control method disclosed as CN107302409A, "an AGC method based on the signal-to-noise ratio estimation of the oversampled signal" published in 2017, 10, month, and 27.
A patent with a publication number of CN 104954033B granted by china in 7/28/7/2017 discloses a fast automatic gain control circuit and method for an OFDM system, which performs calculation and comparison on OFDM signal levels; the chinese patent publication No. CN 102273164B, "Automatic Gain Control (AGC) for OFDM-based transmission in wireless communication networks", granted in chinese 5/8/2015, discloses adjusting initial receiver gain based on cyclic prefix; the patent with the publication number of CN 101964774B granted by China in 9/18/2013, namely, "an automatic gain control method and a control circuit applicable to an OFDM system" discloses that the average of signal energy in a window is calculated by using sliding window processing; the AGC and DC calibration based on cyclic prefix is disclosed in the chinese patent publication CN 102057568B entitled AGC and DC calibration method and system for OFDM/OFDMA systems by year 2015, 8, 26.
The amplitude of the signal is tracked by using a demodulated first-order loop in a document' Zhao Star, design method of intermediate frequency digital coherent AGC realized based on FPGA [ J ]. Sichuan war institute of war 2014,35(2):94-96. In the literature "Liji; in Jiangxian, an OFDM system digital AGC design algorithm [ J ] based on double-loop feedback, modern electronic technology, 2014,37(3): 52-54' adopts a front and back double loop of signal second moment total power. In the document "auspicious, monitor receiver burst signal detection and AGC circuit design and implementation", university of electronic technology, 2014 ", a baseband automatic gain control system with adjustable speed in three steps and capable of adapting to various baseband bandwidths is researched. A scheme based on a delay counter and double-factor convergence is researched in the literature ' Jiangchao-OFDM system channel estimation and AGC technology research and realization thereof ' electronic technology university 2013 '. In the literature "wang; guo hong; a gull; liu Luo jade, a self-adaptive AGC improvement method suitable for an OFDM system [ J ] academic newspaper of information engineering university, 2011,12(5): 550-. In the literature, "wangxing qin; black and brave; an adaptive automatic gain control strategy [ J ] facing an OFDM receiver, electronic bulletin, 2008,36(8):1642 and 1645' designs an average absolute error automatic gain control structure of a hybrid gain compensation coefficient.
The above documents mainly perform feedforward or feedback power control through signal second moment power estimation, adopt different control step lengths, mixing coefficients or multi-stage adjustment structures, and do not perform corresponding power control improvement aiming at the time domain signal characteristics of the OFDM signal, and these methods cannot effectively adjust the signal level under multipath interference or low signal-to-noise ratio, which may cause performance loss of a demodulation algorithm based on threshold detection in the OFDM receiver.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the method comprises the steps of firstly processing based on traditional second-order moment signal power estimation and initial control gain, then extracting accurate signal power in a time domain based on a preamble symbol detected by an OFDM receiver to correct and adjust gain control, and simultaneously extracting a signal power estimation value from a data segment based on a virtual subcarrier to further control and adjust gain, thereby completing the rapid and accurate gain control of a received signal in an OFDM data chain system.
The purpose of the invention is realized by the following technical scheme:
the OFDM signal gain control method based on detection comprises the following steps:
step one, calculating an error tracking signal E of gain control based on a preset initial gain control parameter and power estimation of an OFDM signal secondary moment signalA1While detecting preamble symbol data y of the OFDM signalP(n) and a received signal y (n);
step two, according to the OFDM signal leading symbol data y obtained in the step oneP(n) calculating an error tracking signal E for time-domain gain controlA2；
Step three, calculating an error tracking signal E of frequency domain gain control according to the received signal y (n) obtained in the step oneA3。
In the above OFDM signal gain control method based on detection, the error tracking signal E of gain control in the first stepA1Comprises the following steps:
Figure BDA0001700625300000031
in the formula
y(n)＝ej[2πvn/N+θ]s(n)+z(n)
Figure BDA0001700625300000041
Wherein N is a first ordinal number, N is an integer, N is more than or equal to 0 and less than or equal to N-1; a. therefIs a target signal level; n is the length of the OFDM symbol and is a positive integer; y (n) is a received signal; z (n) is the noise of the channel; theta is channel phase offset; v is channel frequency offset; s (n) signals for the transmitter; esIs the signal power; h (k) is the channel frequency domain response experienced by the OFDM symbol; k is a second ordinal number, and k is an integer; x (k) is a frequency domain representation of the OFDM signal modulated signal.
In the OFDM signal gain control method based on detection, the method for detecting OFDM preamble symbol data in the first step includes:
Figure BDA0001700625300000042
in the formula
Figure BDA0001700625300000043
Wherein the content of the first and second substances,
Figure BDA0001700625300000044
for the estimated value of the starting position of the preamble symbol, argmax { } represents the position of maximum value, M (d) is the detection metric, d is the third ordinal number, d is a positive integer, N is the length of the OFDM symbol, M2Is the second moment of the OFDM signal; n is a first ordinal number, N is an integer, N is more than or equal to 0 and less than or equal to N-1; y (n) is a received signal; y is*(n) is the conjugate of y (n); x (n) is a time domain expression of the OFDM signal modulation signal, x*(n) is the conjugate of x (n).
In the above OFDM signal gain control method based on detection, the OFDM signal preamble symbol data yP(n) into first data segments y of preamble symbols of the OFDM signalP0(n) and a preamble symbol second data segment y of the OFDM signalP1(n) first data section y of preamble symbol of OFDM signalP0(n) and a preamble symbol second data segment y of the OFDM signalP1(n) are the same.
In the above OFDM signal gain control method based on detection, in the second step, the error tracking signal E of time domain gain controlA2Comprises the following steps:
Figure BDA0001700625300000045
wherein, N is the length of OFDM symbol, N is the first ordinal number, N is an integer, N is more than or equal to 0 and less than or equal to N-1; a. therefIs a target signal level; y isP0(n) is the first data segment, y, of the preamble symbol of the OFDM signalP1And (n) is a preamble symbol second data segment of the OFDM signal.
In the OFDM signal gain control method based on detection, the error tracking signal E of the frequency domain gain control in the third stepA3Comprises the following steps:
Figure BDA0001700625300000051
wherein M is2Is the second moment of the OFDM signal; a. therefIs a target signal level; y isv(k) Is of length NvK is a second ordinal number, and k is an integer.
In the above method for controlling gain of OFDM signal based on detection, the OFDM signal is used for a data chain system.
The OFDM signal gain control method based on detection is used for gain control at a receiver.
A recording medium having a computer-readable program recorded thereon, the program, when executed by a processor, implementing the steps of:
step one, calculating an error tracking signal E of gain control based on a preset initial gain control parameter and power estimation of an OFDM signal secondary moment signalA1While detecting preamble symbol data y of the OFDM signalP(n) and a received signal y (n);
step two, according to the OFDM signal leading symbol data y obtained in the step oneP(n) calculating an error tracking signal E for time-domain gain controlA2；
Step three, calculating an error tracking signal E of frequency domain gain control according to the received signal y (n) obtained in the step oneA3。
The OFDM signal gain control device based on detection adopts an OFDM signal gain control method based on detection.
Compared with the prior art, the invention has the following beneficial effects:
(1) the OFDM signal gain control method based on detection is based on the traditional gain control method, and performs gain control adjustment by combining the detected time domain preamble signal power, so that the accuracy of the received signal level of a data chain system is improved compared with the traditional method;
(2) the OFDM signal gain control method based on detection performs gain control adjustment in a frequency domain based on the virtual subcarrier power of a data segment, and can obtain more accurate gain control performance with lower complexity;
(3) the invention extracts information from the detected front section and data section to carry out gain control adjustment based on the detected OFDM signal gain control method, is suitable for the dynamic characteristic environment of a data chain system, and ensures the effectiveness of burst signals in baseband processing in a software radio transceiver.
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FIG. 1 is a block diagram of the application of the gain control method for OFDM signal based detection in a software transceiver;
fig. 2 shows the performance of the gain control error of the OFDM signal gain control method according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram of the application of the detection-based OFDM signal gain control method in a software radio transceiver, in which after a radio frequency input OFDM signal passes through a gain control module, a baseband output signal enters a digital baseband processing unit, and after passing through a gain control module driven by an error tracking signal, a gain control table is controlled by a gain pointer, so as to realize parameter control of the gain control module. The gain control module comprises an LMT (Low noise Amplifier LNA, a mixer and a transimpedance amplifier TIA), a low pass filter LPF and a digital gain control; the gain control tables correspond to LNA, mixer, TIA, LPF and digital parts respectively. And estimating a gain control error (namely an error tracking signal of gain control), correcting the gain error in a time domain (namely the error tracking signal of gain control in the time domain), and correcting the gain error in a frequency domain (namely the error tracking signal of gain control in the frequency domain) to jointly complete gain control.
The OFDM signal gain control method based on detection comprises the following steps:
step one, calculating an error tracking signal E of gain control based on a preset initial gain control parameter and power estimation of an OFDM signal secondary moment signalA1While detecting preamble symbol data y of the OFDM signalP(n) and a received signal y (n).
Gain controlled error tracking signal EA1Comprises the following steps:
Figure BDA0001700625300000071
in the formula
y(n)＝ej[2πvn/N+θ]s(n)+z(n)
Figure BDA0001700625300000072
Wherein the content of the first and second substances,
Figure BDA0001700625300000073
for signal power estimation, M2As second order moments of OFDM signals
Figure BDA0001700625300000074
N is a first ordinal number, N is an integer, N is more than or equal to 0 and less than or equal to N-1; a. therefIs a target signal level; n is the length of the OFDM symbol and is a positive integer; y (n) isReceiving a signal; z (n) is the noise of the channel; theta is channel phase offset; v is channel frequency offset; s (n) signals for the transmitter; esIs the signal power; h (k) is the channel frequency domain response experienced by the OFDM symbol; k is a second ordinal number, and k is an integer; x (k) is a frequency domain representation of the OFDM signal modulated signal.
Preamble symbol data y of the OFDM signalP(n) into first data segments y of preamble symbols of the OFDM signalP0(n) and a preamble symbol second data segment y of the OFDM signalP1(n) first data section y of preamble symbol of OFDM signalP0(n) and a preamble symbol second data segment y of the OFDM signalP1(n) are the same.
The method for detecting the OFDM preamble symbol data comprises the following steps:
Figure BDA0001700625300000075
in the formula
Figure BDA0001700625300000076
Wherein the content of the first and second substances,
Figure BDA0001700625300000077
for the estimated value of the starting position of the preamble symbol, argmax { } represents the position of maximum value, M (d) is the detection metric, d is the third ordinal number, d is a positive integer, N is the length of the OFDM symbol, M2Is the second moment of the OFDM signal; n is a first ordinal number, N is an integer, N is more than or equal to 0 and less than or equal to N-1; y (n) is a received signal; y is*(n) is the conjugate of y (n); x (n) is a time domain expression of the OFDM signal modulation signal, x*(n) is the conjugate of x (n). Based on the estimated value of the starting position of the preamble symbol
Figure BDA0001700625300000081
The initial position d of the preamble symbol can be obtainedPAnd corresponding preamble symbol data yP(n)。
Step two, according to the OFDM signal leading symbol data y obtained in the step oneP(n) calculating an error tracking signal E for time-domain gain controlA2。
Time-domain gain-controlled error tracking signal EA2Comprises the following steps:
Figure BDA0001700625300000082
wherein, N is the length of OFDM symbol, N is the first ordinal number, N is an integer, N is more than or equal to 0 and less than or equal to N-1; a. therefIs a target signal level; y isP0(n) is the first data segment, y, of the preamble symbol of the OFDM signalP1And (n) is a preamble symbol second data segment of the OFDM signal. Error tracking signal E with time-domain gain controlA2And realizing the level adjustment of the received signal.
Step three, transforming the received signals Y (N) and Y (N) obtained in the step one into a frequency domain through N-point Fourier transform to obtain Y (k), wherein k is more than or equal to 0 and less than or equal to N-1, and Yv(k) Is of length NvVirtual sub-carrier of, Yu(k) Is of length NuOf the modulated signal subcarrier, N ═ Nv+NuCalculating a frequency domain gain controlled error tracking signal EA3。
Frequency domain gain controlled error tracking signal EA3Comprises the following steps:
Figure BDA0001700625300000083
wherein M is2Is the second moment of the OFDM signal; a. therefIs a target signal level; y isv(k) Is of length NvK is a second ordinal number, and k is an integer. Error tracking signal E with frequency domain gain controlA3And realizing the level adjustment of the received signal.
The OFDM signal gain control method based on detection adopts an error tracking signal E of gain controlA1Time-domain gain-controlled error tracking signal EA2Frequency domain gain controlled error tracking signal EA3Together completing the gain control.
The OFDM signal gain control method based on detection can be used for realizing gain control at a receiver end of a data chain system.
A recording medium having a computer-readable program recorded thereon, the program, when executed by a processor, implementing the steps of:
step one, calculating an error tracking signal E of gain control based on a preset initial gain control parameter and power estimation of an OFDM signal secondary moment signalA1While detecting preamble symbol data y of the OFDM signalP(n) and a received signal y (n).
Gain controlled error tracking signal EA1Comprises the following steps:
Figure BDA0001700625300000091
in the formula
y(n)＝ej[2πv/nN+θ]s(n)+z(n)
Figure BDA0001700625300000092
Wherein the content of the first and second substances,
Figure BDA0001700625300000093
for signal power estimation, M2As second order moments of OFDM signals
Figure BDA0001700625300000094
N is a first ordinal number, N is an integer, N is more than or equal to 0 and less than or equal to N-1; a. therefIs a target signal level; n is the length of the OFDM symbol and is a positive integer; y (n) is a received signal; z (n) is the noise of the channel; theta is channel phase offset; v is channel frequency offset; s (n) signals for the transmitter; esIs the signal power; h (k) is the channel frequency domain response experienced by the OFDM symbol; k is a second ordinal number, and k is an integer; x (k) is a frequency domain representation of the OFDM signal modulated signal.
Preamble symbol data y of the OFDM signalP(n) into first data segments y of preamble symbols of the OFDM signalP0(n) and OFDM signalPreamble symbol second data segment yP1(n) first data section y of preamble symbol of OFDM signalP0(n) and a preamble symbol second data segment y of the OFDM signalP1(n) are the same.
The method for detecting the OFDM preamble symbol data comprises the following steps:
Figure BDA0001700625300000101
in the formula
Figure BDA0001700625300000102
Wherein the content of the first and second substances,
Figure BDA0001700625300000104
for the estimated value of the starting position of the preamble symbol, argmax { } represents the position of maximum value, M (d) is the detection metric, d is the third ordinal number, d is a positive integer, N is the length of the OFDM symbol, M2Is the second moment of the OFDM signal; n is a first ordinal number, N is an integer, N is more than or equal to 0 and less than or equal to N-1; y (n) is a received signal; y is*(n) is the conjugate of y (n); x (n) is a time domain expression of the OFDM signal modulation signal, x*(n) is the conjugate of x (n). Based on the estimated value of the starting position of the preamble symbol
Figure BDA0001700625300000105
The initial position d of the preamble symbol can be obtainedPAnd corresponding preamble symbol data yP(n)。
Step two, according to the OFDM signal leading symbol data y obtained in the step oneP(n) calculating an error tracking signal E for time-domain gain controlA2。
Time-domain gain-controlled error tracking signal EA2Comprises the following steps:
Figure BDA0001700625300000103
wherein N is the length of OFDM symbol, and N is the secondAn ordinal number, N is an integer, N is more than or equal to 0 and less than or equal to N-1; a. therefIs a target signal level; y isP0(n) is the first data segment, y, of the preamble symbol of the OFDM signalP1And (n) is a preamble symbol second data segment of the OFDM signal. Error tracking signal E with time-domain gain controlA2And realizing the level adjustment of the received signal.
Step three, transforming the received signals Y (N) and Y (N) obtained in the step one into a frequency domain through N-point Fourier transform to obtain Y (k), wherein k is more than or equal to 0 and less than or equal to N-1, and Yv(k) Is of length NvVirtual sub-carrier of, Yu(k) Is of length NuOf the modulated signal subcarrier, N ═ Nv+NuCalculating a frequency domain gain controlled error tracking signal EA3。
Frequency domain gain controlled error tracking signal EA3Comprises the following steps:
Figure BDA0001700625300000111
wherein M is2Is the second moment of the OFDM signal; a. therefIs a target signal level; y isv(k) Is of length NvK is a second ordinal number, and k is an integer. Error tracking signal E with frequency domain gain controlA3And realizing the level adjustment of the received signal.
The OFDM signal gain control device based on detection adopts an OFDM signal gain control method based on detection.
Example 1:
fig. 2 shows the simulation performance of the OFDM signal gain control method based on detection according to the present invention, where N512 long FFT signals are used for QPSK modulation, the gain control error simulated by using the gain control method of the present invention and the gain control error simulated by using the conventional second-order moment method are normalized to be biased in an AWGN channel with SNR of-10 dB to 20dB, and the vertical axis is the percentage of the bias, and it can be known from simulation result analysis that the gain control adjustment method of the present invention is 18dB higher than the conventional second-order moment gain control method, and can perform gain control accurately when SNR is-10 dB, but the conventional second-order moment gain control method can achieve the same performance when SNR is greater than 10 dB.
The above description is only for the best mode of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.
Those skilled in the art will appreciate that those matters not described in detail in the present specification are well known in the art.

Claims (7)

1. The OFDM signal gain control method based on detection is characterized in that: the method comprises the following steps:
step one, calculating an error tracking signal E of gain control based on a received signal y (n)A1And simultaneously detecting preamble symbol data y of OFDM signal in received signal y (n)P(n)；
Step two, according to the OFDM signal leading symbol data y obtained in the step oneP(n) calculating an error tracking signal E for time-domain gain controlA2；
Step three, calculating an error tracking signal E of frequency domain gain control according to the received signal y (n) obtained in the step oneA3；
In the first step, the method for detecting the preamble symbol data of the OFDM signal comprises:
Figure FDA0002861601460000011
in the formula
Figure FDA0002861601460000012
Wherein the content of the first and second substances,
Figure FDA0002861601460000013
for the estimated value of the starting position of the preamble symbol, argmax { } represents the position of the maximum value, M (d) is the detection metric, d is the third ordinal number, d is a positive integer,n is the length of the OFDM symbol, M2Is the second moment of the OFDM signal; n is a first ordinal number, N is an integer, N is more than or equal to 0 and less than or equal to N-1; y (n) is a received signal; y is*(n) is the conjugate of y (n); x (n) is a time domain expression of the OFDM signal modulation signal, x*(n) is the conjugate of x (n); according to
Figure FDA0002861601460000014
Then y is obtainedP(n)。
2. The detection-based OFDM signal gain control method of claim 1, wherein: error tracking signal E of gain control in the first stepA1Comprises the following steps:
Figure FDA0002861601460000015
in the formula
y(n)＝ej[2πvn/N+θ]s(n)+z(n)
Figure FDA0002861601460000021
Wherein N is a first ordinal number, N is an integer, N is more than or equal to 0 and less than or equal to N-1; a. therefIs a target signal level; n is the length of the OFDM symbol and is a positive integer; y (n) is a received signal; z (n) is the noise of the channel; theta is channel phase offset; v is channel frequency offset; s (n) signals for the transmitter; esIs the signal power; h (k) is the channel frequency domain response experienced by the OFDM symbol; k is a second ordinal number, and k is an integer; x (k) is a frequency domain representation of the OFDM signal modulated signal.
3. The detection-based OFDM signal gain control method of claim 1, wherein: preamble symbol data y of the OFDM signalP(n) into first data segments y of preamble symbols of the OFDM signalP0(n) and a preamble symbol second data segment y of the OFDM signalP1(n) first number of preamble symbols of OFDM signalAccording to segment yP0(n) and a preamble symbol second data segment y of the OFDM signalP1(n) are the same.
4. The detection-based OFDM signal gain control method of claim 1, wherein: error tracking signal E of time domain gain control in the second stepA2Comprises the following steps:
Figure FDA0002861601460000022
wherein, N is the length of OFDM symbol, N is the first ordinal number, N is an integer, N is more than or equal to 0 and less than or equal to N-1; a. therefIs a target signal level; y isP0(n) is the first data segment, y, of the preamble symbol of the OFDM signalP1And (n) is a preamble symbol second data segment of the OFDM signal.
5. The detection-based OFDM signal gain control method of claim 1, wherein: error tracking signal E of frequency domain gain control in the third stepA3Comprises the following steps:
Figure FDA0002861601460000023
wherein M is2Is the second moment of the OFDM signal; a. therefIs a target signal level; y isv(k) Is of length NvK is a second ordinal number, and k is an integer.
6. The detection-based OFDM signal gain control method of claim 1, wherein: the OFDM signal is for a data chain system.
7. The detection-based OFDM signal gain control method of claim 1, wherein: the OFDM signal gain control method based on detection is used for gain control at a receiver.
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