CN116232436A - DVB-S2 signal demodulation method, demodulation device and receiver - Google Patents
DVB-S2 signal demodulation method, demodulation device and receiver Download PDFInfo
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Abstract
The invention discloses a DVB-S2 signal demodulation method, a demodulation device and a receiver, which relate to the field of digital signal processing and have the technical scheme that: down-converting both the radio frequency signal and the reference signal into intermediate frequency signals; respectively carrying out high-speed AD sampling treatment on the two paths of intermediate frequency signals to obtain two paths of sampling signals; carrying out data synchronization processing on the two paths of sampling signals by using an interference detection algorithm and a time delay estimation algorithm to obtain sampling signals corresponding to the radio frequency signals after time delay synchronization; using a reference signal as a reference, adopting a frequency offset estimation algorithm to estimate and correct a sampling signal corresponding to the radio frequency signal after time delay synchronization, and adopting a timing recovery algorithm to synchronously process the timing deviation of the estimated and corrected sampling signal to obtain a mixed signal of the optimal sampling point; performing adaptive filtering processing on the real part signal and the imaginary part signal of the mixed signal by utilizing the real part signal and the imaginary part signal of the reference signal to obtain a digital signal; and demodulating and decoding the digital signal to obtain the DVB-S2 signal.
Description
Technical Field
The present invention relates to the field of digital signal processing, and more particularly, to a DVB-S2 signal demodulation method, a demodulation apparatus, and a receiver.
Background
DVB-S2 is a second generation digital satellite broadcasting standard developed on the basis of DVB. In the standard specification of the second generation digital satellite broadcasting system, a Frame (Frame) is mainly used as a basic unit of transmission. Each frame of Data is mainly composed of a Header portion and a Data portion, so that how to demodulate a received signal for a receiving end affects the quality of the acquisition of the back-end Data.
The DVB-S2 signal is transmitted by a satellite, the strength of the signal reaching the ground is weaker, when the self-interference signal with the same frequency exists, the signal condition can not meet the requirement of the receiver on the demodulation signal to noise ratio, and the DVB-S2 signal can not be demodulated. In order to solve the problem of separation of self-interference signals at the same frequency in the prior art, the prior art adopts a radio frequency cancellation method, but the cost of an antenna and a radio frequency part is required to be additionally increased, the bandwidth is easily limited and the electromagnetic environment where the bandwidth is positioned is limited, and the separation effect cannot be ensured. At present, the other digital interference cancellation is performed by adopting a multi-stage digital filtering mode, the environment where the signal is located is not described, the application environment is a duplex communication system, and the applicability for DVB-S2 signal reception is unknown.
Therefore, how to solve the problem that the signal-to-noise ratio of the DVB-S2 signal is difficult to reach the demodulation requirement of the receiver under the self-interference condition of the co-frequency simultaneous signal is an urgent need to be solved at present.
Disclosure of Invention
The invention aims to provide a demodulation method, a demodulation device and a receiver for DVB-S2 signals, which aim at the problem that the demodulation signal to noise ratio under the condition of same-frequency simultaneous interference cannot meet the demodulation threshold, and adopt algorithms such as interference detection, frequency offset estimation, self-adaptive filtering and the like, so that the separation of the same-frequency simultaneous interference signals is realized, and the demodulation problem of the DVB-S2 signals is solved.
The technical aim of the invention is realized by the following technical scheme:
in a first aspect of the present application, a method for demodulating a DVB-S2 signal is provided, including:
when receiving the radio frequency signal under the same-frequency simultaneous interference condition, down-converting the radio frequency signal and the reference signal into intermediate frequency signals; the frequency bands of the radio frequency signal and the reference signal are L frequency bands, and the reference signal is a local sequence signal;
respectively carrying out high-speed AD sampling processing on the two paths of intermediate frequency signals to obtain two paths of sampling signals, wherein the radio frequency signal corresponds to a first sampling signal, and the reference signal corresponds to a second sampling signal;
carrying out data synchronization processing on the two paths of sampling signals by using an interference detection algorithm and a time delay estimation algorithm to obtain sampling signals corresponding to the radio frequency signals after time delay synchronization;
using a reference signal as a reference, adopting a frequency offset estimation algorithm to estimate and correct a sampling signal corresponding to the radio frequency signal after time delay synchronization, and adopting a timing recovery algorithm to synchronously process the timing deviation of the estimated and corrected sampling signal to obtain a mixed signal of the optimal sampling point;
performing adaptive filtering processing on the real part signal and the imaginary part signal of the mixed signal by utilizing the real part signal and the imaginary part signal of the reference signal to obtain a digital signal;
and demodulating and decoding the digital signal according to the communication protocol of the DVB-S2 signal to obtain the DVB-S2 signal.
In one embodiment, the two paths of intermediate frequency signals are respectively subjected to high-speed AD sampling processing by low-pass sampling to obtain two paths of 12-bit digital sampling signals.
In one embodiment, the interference detection algorithm and the time delay estimation algorithm are used for carrying out data synchronization processing on two paths of sampling signals to obtain sampling signals corresponding to radio frequency signals after time delay synchronization, and the method specifically comprises the following steps:
calculating the power of two adjacent frames of the sampling signal corresponding to the reference signal by utilizing an interference detection algorithm, and when the power difference value of the two adjacent frames is smaller than a preset difference value and the frame number of the two adjacent frames is larger than the frame number of the sampling signal corresponding to the radio frequency signal, the frame number of the sampling signal corresponding to the radio frequency signal is free from interference, so that coarse synchronization of the radio frequency signal under the same-frequency simultaneous interference condition is realized;
and determining the time delay between two adjacent frames with changed power by using a time delay estimation algorithm to obtain sampling signals corresponding to the radio frequency signals after time delay synchronization, thereby realizing fine synchronization of the radio frequency signals under the condition of same-frequency simultaneous interference.
In one embodiment, with reference to the reference signal, a frequency offset estimation algorithm is used to estimate and correct a sampling signal corresponding to the radio frequency signal after time delay synchronization, including:
and estimating the sampling signals corresponding to the radio frequency signals after time delay synchronization by taking the reference signals as the standard to obtain estimated values, and performing mixing processing according to the estimated values to correct the frequency offset of the sampling signals corresponding to the radio frequency signals after time delay synchronization.
In one embodiment, a phase difference between two pilot sequences is calculated; and calculating corrected frequency offset according to the interval between the two sections of pilot sequences, the phase difference and the sampling rate of sampling processing, wherein the estimation is carried out by adopting a plurality of sections of pilot sequences with different intervals.
In one embodiment, the real part signal and the imaginary part signal of the mixed signal are adaptively filtered by using the real part signal and the imaginary part signal of the reference signal to obtain a digital signal, specifically:
extracting a real part signal of a reference signal as a reference object signal, taking the real part signal of a mixed signal as a desired signal, and eliminating real part interference mixed in the mixed signal based on an adaptive interference cancellation algorithm;
extracting an imaginary signal of a reference signal as a reference object signal, using a real signal of a mixed signal as a desired signal, and canceling imaginary interference mixed in the mixed signal based on an adaptive interference cancellation algorithm;
extracting a real part signal of a reference signal as a reference object signal, an imaginary part signal of a mixed signal as a desired signal, and canceling imaginary part interference mixed in the mixed signal based on an adaptive interference cancellation algorithm; and
the real part signal of the reference signal is extracted as a reference object signal, the imaginary part signal of the mixed signal is taken as a desired signal, and the mixed signal is cancelled to mix in the imaginary part interference based on an adaptive interference cancellation algorithm.
In one embodiment, an adaptive filter process for real and imaginary signals of a mixed signal is implemented based on an adaptive filter.
In a second aspect of the present application, there is provided a DVB-S2 signal demodulation apparatus comprising:
the down-conversion module is used for down-converting the radio frequency signal and the reference signal into intermediate frequency signals when receiving the radio frequency signal under the condition of same-frequency simultaneous interference; the frequency bands of the radio frequency signal and the reference signal are L frequency bands, and the reference signal is a local sequence signal;
the sampling module is used for respectively carrying out high-speed AD sampling processing on the two paths of intermediate frequency signals to obtain two paths of sampling signals, wherein the radio frequency signals correspond to the first sampling signals, and the reference signals correspond to the second sampling signals;
the synchronous module is used for carrying out data synchronous processing on the two paths of sampling signals by using an interference detection algorithm and a time delay estimation algorithm to obtain sampling signals corresponding to the radio frequency signals after time delay synchronization;
the frequency offset estimation module is used for estimating and correcting the sampling signals corresponding to the radio frequency signals after the time synchronization by using the frequency offset estimation algorithm and synchronously processing the timing deviation of the estimated and corrected sampling signals by using the timing recovery algorithm to obtain a mixed signal of the optimal sampling points;
the interference cancellation module is used for carrying out self-adaptive filtering processing on the real part signal and the imaginary part signal of the mixed signal by utilizing the real part signal and the imaginary part signal of the reference signal to obtain a digital signal;
and the demodulation module is used for demodulating and decoding the digital signal according to the communication protocol of the DVB-S2 signal to obtain the DVB-S2 signal.
In one embodiment, the sampling module is specifically further configured to perform high-speed AD sampling processing on the two paths of intermediate frequency signals by using low-pass sampling, so as to obtain two paths of 12-bit digital sampling signals.
In a third aspect of the present application, there is provided a receiver comprising a DVB-S2 signal demodulation apparatus according to the second aspect of the present application.
Compared with the prior art, the invention has the following beneficial effects:
aiming at the problem that the demodulation signal-to-noise ratio under the same-frequency simultaneous interference condition can not meet the demodulation threshold, the invention adopts the algorithms such as interference detection, frequency offset estimation, self-adaptive filtering and the like, realizes the separation of the same-frequency simultaneous interference signals, and solves the demodulation problem of DVB-S2 signals.
Drawings
The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention. In the drawings:
fig. 1 is a schematic flow chart of a DVB-S2 signal demodulation method according to an embodiment of the present application;
fig. 2 is a schematic flow chart of data synchronization in a DVB-S2 signal demodulation method according to an embodiment of the present application;
FIG. 3 is a schematic flow chart of a timing recovery algorithm according to an embodiment of the present application;
fig. 4 is a block diagram of an adaptive filter according to an embodiment of the present application;
fig. 5 is a flowchart of adaptive filtering interference suppression provided in an embodiment of the present application;
fig. 6 is a block diagram of a DVB-S2 signal demodulation device according to an embodiment of the present application.
Detailed Description
For the purpose of making apparent the objects, technical solutions and advantages of the present invention, the present invention will be further described in detail with reference to the following examples and the accompanying drawings, wherein the exemplary embodiments of the present invention and the descriptions thereof are for illustrating the present invention only and are not to be construed as limiting the present invention.
It should be appreciated that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
As described in the background art, the present embodiment provides a method for demodulating DVB-S2 signal, which is applied to a signal demodulator, and aims at the problem that the signal-to-noise ratio of DVB-S2 signal is difficult to reach the demodulation requirement of a receiver under the self-interference condition of the same-frequency simultaneous signal, and the method adopts algorithms such as interference detection, frequency offset estimation, adaptive filtering, etc. to realize the separation of the same-frequency simultaneous interference signal, solve the demodulation problem of DVB-S2 signal, and is used as the common knowledge of the person skilled in the art to implement the operation of DVB-S2 signal demodulation by carrying an FPGA chip, a memory, etc. in the signal demodulator.
Referring to fig. 1, fig. 1 is a flow chart of a DVB-S2 signal demodulation method according to an embodiment of the present application, as shown in fig. 1, including steps S110-S160:
s110, when receiving the radio frequency signal under the same-frequency simultaneous interference condition, down-converting the radio frequency signal and the reference signal into intermediate frequency signals; the frequency bands of the radio frequency signal and the reference signal are L frequency bands, and the reference signal is a local sequence signal.
Specifically, the radio frequency signals including co-frequency and co-interference are received by an antenna, and converted into an L frequency band by a BNC, wherein the antenna can be a phased array antenna, a radar antenna, a one-dimensional circularly polarized antenna array, a two-dimensional circularly polarized antenna array, and the like. The frequency band of the intermediate frequency signal is 140MHz.
S120, respectively performing high-speed AD sampling processing on the two paths of intermediate frequency signals to obtain two paths of sampling signals, wherein the radio frequency signal corresponds to a first sampling signal, and the reference signal corresponds to a second sampling signal.
In this embodiment, high-speed AD sampling processing is performed on the two paths of intermediate frequency signals respectively to obtain two paths of sampling signals, and specifically, high-speed AD sampling processing is performed on the two paths of intermediate frequency signals respectively by low-pass sampling to obtain two paths of 12-bit digital sampling signals. The "low-pass sampling theorem" may be abbreviated as "sampling theorem" when the sampling frequency fs.max is greater than 2 times the highest frequency fmax in the signal (fs.max > =2fmax) in the process of performing conversion of the analog/digital signal, and the digital signal after sampling completely retains the information in the original signal. This conclusion is called the "sampling theorem". In general practical application, the sampling frequency is ensured to be 5-10 times of the highest frequency of the signal; the sampling theorem is the basis of information quantization, so that discrete 2-ary bits represent the theoretical basis of continuous analog quantity.
And S130, carrying out data synchronization processing on the two paths of sampling signals by using an interference detection algorithm and a time delay estimation algorithm to obtain sampling signals corresponding to the radio frequency signals after time delay synchronization.
In this embodiment, since the signal processing process needs to use the reference signal as a reference, the two sampling signals must be synchronized by the interference detection and time estimation method. The interference signals in the mixed signal are roughly synchronized through the power detection of the reference signal, and on the basis, fine synchronization is performed by utilizing the correlation of the frame start of the DVB-S2 signal, and the fine synchronization is performed in two adjacent frames with power change. Specifically, the data synchronization processing of the two paths of sampling signals can be realized by using the FPGA carried in the signal demodulator.
And S140, taking the reference signal as a reference, adopting a frequency offset estimation algorithm to estimate and correct the sampling signal corresponding to the radio frequency signal after time synchronization, and adopting a timing recovery algorithm to synchronously process the timing deviation of the estimated and corrected sampling signal to obtain the mixed signal of the optimal sampling point.
In this embodiment, the synchronization between the reference signal and the radio frequency signal is realized by roughly estimating the synchronization frame structure specific to DVB-S2 and finely synchronizing the synchronization frame structure in combination with the detection of the interference signal power. And adopting a timing recovery algorithm to perform timing recovery on the signals. The ADC samples with timing offset and the signal sampled by the ADC needs to be timing recovered. Specifically, as shown in fig. 3, a hardware composition structure for performing timing recovery on the signals sampled by the ADC is built based on the interpolation filter, the loop filter structure and the NCO controller (digital oscillator), so that the sampled signals with timing deviation after the ADC is sampled are synchronously processed, and the time synchronization of the sampled signals is ensured.
S150, performing adaptive filtering processing on the real part signal and the imaginary part signal of the mixed signal by using the real part signal and the imaginary part signal of the reference signal to obtain a digital signal.
In this embodiment, an adaptive filter structure is used to separate the signals. In one embodiment, the adaptive filter is based on an adaptive filter to perform adaptive filtering on a real signal and an imaginary signal of a mixed signal, and the adaptive filter structure is shown in fig. 4, and in particular, the adaptive filter structure is a prior art, which is not described in detail in this embodiment. The reference signal x (n) is reconstructed into y (n), and the y (n) is very close to the interference in the mixed signal d (n), so that the weak signal e (n) is obtained by cancellation, and the weak signal e (n) is a digital signal. As shown in fig. 5, the real part signal and the imaginary part signal of the mixed signal are adaptively filtered using the real part signal and the imaginary part signal of the reference signal, thereby implementing cancellation of the interference signal of the mixed signal. Specifically, extracting a real part signal of a reference signal as a reference object signal, taking a real part signal of a mixed signal as a desired signal, and canceling real part interference mixed in the mixed signal based on an adaptive interference cancellation algorithm; extracting an imaginary signal of a reference signal as a reference object signal, using a real signal of a mixed signal as a desired signal, and canceling imaginary interference mixed in the mixed signal based on an adaptive interference cancellation algorithm; extracting a real part signal of a reference signal as a reference object signal, an imaginary part signal of a mixed signal as a desired signal, and canceling imaginary part interference mixed in the mixed signal based on an adaptive interference cancellation algorithm; and extracting a real part signal of the reference signal as a reference object signal, an imaginary part signal of the mixed signal as a desired signal, and canceling imaginary part interference mixed in the mixed signal based on an adaptive interference cancellation algorithm.
And S160, demodulating and decoding the digital signal according to the communication protocol of the DVB-S2 signal to obtain the DVB-S2 signal.
In this embodiment, the digital signal is demodulated and decoded according to the communication protocol of the DVB-S2 signal, which belongs to the conventional technical means of those skilled in the art, and redundant description is not made here.
In summary, according to the demodulation method provided by the embodiment, aiming at the problem that the demodulation signal-to-noise ratio under the condition of the same-frequency simultaneous interference cannot meet the demodulation threshold, the algorithms such as interference detection, frequency offset estimation, adaptive filtering and the like are adopted, so that the separation of the same-frequency simultaneous interference signals is realized, and the demodulation problem of DVB-S2 signals is solved.
Further, as shown in fig. 2, fig. 2 is a data synchronization flow chart in the DVB-S2 signal demodulation method provided in the embodiment of the present application, and performs data synchronization processing on two paths of sampling signals by using an interference detection algorithm and a time delay estimation algorithm to obtain sampling signals corresponding to radio frequency signals after time delay synchronization, which specifically includes: calculating the power of two adjacent frames of the sampling signal corresponding to the reference signal by utilizing an interference detection algorithm, and when the power difference value of the two adjacent frames is smaller than a preset difference value and the frame number of the two adjacent frames is larger than the frame number of the sampling signal corresponding to the radio frequency signal, the frame number of the sampling signal corresponding to the radio frequency signal is free from interference, so that coarse synchronization of the radio frequency signal under the same-frequency simultaneous interference condition is realized; and determining the time delay between two adjacent frames with changed power by using a time delay estimation algorithm to obtain sampling signals corresponding to the radio frequency signals after time delay synchronization, thereby realizing fine synchronization of the radio frequency signals under the condition of same-frequency simultaneous interference.
In this embodiment, two adjacent frames are i frame and i+1 frame, the power detection of the reference signal is used to perform coarse synchronization on the interference signal in the mixed signal, and on the basis, the correlation of the frame start is used to perform fine synchronization, where the fine synchronization is performed in two adjacent frames with power change.
In one embodiment, with reference signals as references, estimating and correcting sampling signals corresponding to the radio frequency signals after time delay synchronization by using a frequency offset estimation algorithm includes: and estimating the sampling signals corresponding to the radio frequency signals after time delay synchronization by taking the reference signals as the standard to obtain estimated values, and performing mixing processing according to the estimated values to correct the frequency offset of the sampling signals corresponding to the radio frequency signals after time delay synchronization.
In this embodiment, a method of coarse estimation and then fine estimation is adopted, for example, in one embodiment, a phase difference between two pilot sequences is calculated; and calculating corrected frequency offset according to the interval between the two sections of pilot sequences, the phase difference and the sampling rate of sampling processing, wherein the estimation is carried out by adopting a plurality of sections of pilot sequences with different intervals. The calculation method comprises the following steps:
P＝Pilot1*conj(Pilot2)；
P_mean＝mean(P)；
wherein, pilot1 is the first segment Pilot sequence, pilot2 is the second segment Pilot sequence, mean is the average value, angle is the phase angle, and the frequency is calculated according to the following formula:
where N is the interval between two pilot sequences, f s For the sampling rate, Δf is the estimated frequency offset, but since the calculated range of phase is [ -pi, pi]Therefore, the frequency offset ranges calculated by different N can be different, and the specific formula is as follows:
from the above, f s Under certain conditions, the smaller N is, the larger the frequency offset range which can be estimated is, but the worse the precision is, on the contrary, the smaller the frequency offset range which can be estimated is, the better the precision is, and in order to accurately estimate the frequency offset, a plurality of sections of pilot frequencies with different intervals are adopted for estimation. The frequency offset estimation precision after fine synchronization can be adjusted to 2-3 Hz.
Based on the same technical concept, please refer to fig. 6, fig. 6 is a block diagram of a DVB-S2 signal demodulation device according to an embodiment of the present application, and since the principle of solving the problem of the DVB-S2 signal demodulation device is similar to that of the DVB-S2 signal demodulation method shown in fig. 1, an implementation manner of the device may refer to an embodiment of the method shown in fig. 1, as shown in fig. 6, the device includes:
the down-conversion module 610 is configured to down-convert, when receiving a radio frequency signal under the condition of co-frequency and co-interference, both the radio frequency signal and a reference signal into intermediate frequency signals; the frequency bands of the radio frequency signal and the reference signal are L frequency bands, and the reference signal is a local sequence signal;
the sampling module 620 is configured to perform high-speed AD sampling processing on the two paths of intermediate frequency signals respectively to obtain two paths of sampled signals, where the radio frequency signal corresponds to the first sampled signal and the reference signal corresponds to the second sampled signal;
the synchronization module 630 is configured to perform data synchronization processing on the two paths of sampling signals by using an interference detection algorithm and a time delay estimation algorithm, so as to obtain sampling signals corresponding to the radio frequency signals after time delay synchronization;
the frequency offset estimation module 640 is used for estimating and correcting the sampling signals corresponding to the radio frequency signals after time delay synchronization by adopting a frequency offset estimation algorithm and synchronously processing the timing deviation of the estimated and corrected sampling signals by adopting a timing recovery algorithm, so as to obtain a mixed signal of the optimal sampling points;
an interference cancellation module 650, configured to perform adaptive filtering processing on the real signal and the imaginary signal of the mixed signal by using the real signal and the imaginary signal of the reference signal, so as to obtain a digital signal;
the demodulation module 660 is configured to demodulate and decode the digital signal according to the communication protocol of the DVB-S2 signal, to obtain the DVB-S2 signal.
It can be seen that the DVB-S2 signal demodulation device provided by the embodiment has the following beneficial effects: aiming at the problem that the demodulation signal-to-noise ratio under the same-frequency simultaneous interference condition cannot meet the demodulation threshold, the method adopts algorithms such as interference detection, frequency offset estimation, self-adaptive filtering and the like, realizes the separation of the same-frequency simultaneous interference signals, and solves the demodulation problem of DVB-S2 signals.
Further, the sampling module 620 is specifically further configured to perform high-speed AD sampling processing on the two paths of intermediate frequency signals by using low-pass sampling, so as to obtain two paths of 12-bit digital sampling signals.
The embodiment of the invention also provides a receiver which comprises the DVB-S2 signal demodulation device. The DVB-S2 signal demodulation device is utilized to demodulate the received radio frequency signal, so that signal demodulation under the condition of large interference signal ratio can be realized, and subsequent operation is facilitated.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (10)
1. A method for demodulating a DVB-S2 signal, comprising:
when receiving the radio frequency signal under the same-frequency simultaneous interference condition, down-converting the radio frequency signal and the reference signal into intermediate frequency signals; the frequency bands of the radio frequency signal and the reference signal are L frequency bands, and the reference signal is a local sequence signal;
respectively carrying out high-speed AD sampling processing on the two paths of intermediate frequency signals to obtain two paths of sampling signals, wherein the radio frequency signal corresponds to a first sampling signal, and the reference signal corresponds to a second sampling signal;
carrying out data synchronization processing on the two paths of sampling signals by using an interference detection algorithm and a time delay estimation algorithm to obtain sampling signals corresponding to the radio frequency signals after time delay synchronization;
using a reference signal as a reference, adopting a frequency offset estimation algorithm to estimate and correct a sampling signal corresponding to the radio frequency signal after time delay synchronization, and adopting a timing recovery algorithm to synchronously process the timing deviation of the estimated and corrected sampling signal to obtain a mixed signal of the optimal sampling point;
performing adaptive filtering processing on the real part signal and the imaginary part signal of the mixed signal by utilizing the real part signal and the imaginary part signal of the reference signal to obtain a digital signal;
and demodulating and decoding the digital signal according to the communication protocol of the DVB-S2 signal to obtain the DVB-S2 signal.
2. The method for demodulating a DVB-S2 signal according to claim 1, wherein the two paths of intermediate frequency signals are respectively subjected to high-speed AD sampling processing by low-pass sampling, so as to obtain two paths of 12-bit digital sampled signals.
3. The method for demodulating a DVB-S2 signal according to claim 1 or 2, wherein the data synchronization processing is performed on the two paths of sampling signals by using an interference detection algorithm and a time delay estimation algorithm, so as to obtain sampling signals corresponding to the radio frequency signals after time delay synchronization, which specifically are:
calculating the power of two adjacent frames of the sampling signal corresponding to the reference signal by utilizing an interference detection algorithm, and when the power difference value of the two adjacent frames is smaller than a preset difference value and the frame number of the two adjacent frames is larger than the frame number of the sampling signal corresponding to the radio frequency signal, the frame number of the sampling signal corresponding to the radio frequency signal is free from interference, so that coarse synchronization of the radio frequency signal under the same-frequency simultaneous interference condition is realized;
and determining the time delay between two adjacent frames with changed power by using a time delay estimation algorithm to obtain sampling signals corresponding to the radio frequency signals after time delay synchronization, thereby realizing fine synchronization of the radio frequency signals under the condition of same-frequency simultaneous interference.
4. A method for demodulating a DVB-S2 signal according to claim 3, wherein estimating and correcting a sampling signal corresponding to a radio frequency signal after time delay synchronization by using a frequency offset estimation algorithm with reference to the reference signal includes:
and estimating the sampling signals corresponding to the radio frequency signals after time delay synchronization by taking the reference signals as the standard to obtain estimated values, and performing mixing processing according to the estimated values to correct the frequency offset of the sampling signals corresponding to the radio frequency signals after time delay synchronization.
5. The method for demodulating a DVB-S2 signal according to claim 4 wherein the phase difference between two pilot sequences is calculated; and calculating corrected frequency offset according to the interval between the two sections of pilot sequences, the phase difference and the sampling rate of sampling processing, wherein the estimation is carried out by adopting a plurality of sections of pilot sequences with different intervals.
6. The method for demodulating a DVB-S2 signal according to claim 1, wherein the real signal and the imaginary signal of the mixed signal are adaptively filtered by using the real signal and the imaginary signal of the reference signal to obtain the digital signal, specifically:
extracting a real part signal of a reference signal as a reference object signal, taking the real part signal of a mixed signal as a desired signal, and eliminating real part interference mixed in the mixed signal based on an adaptive interference cancellation algorithm;
extracting an imaginary signal of a reference signal as a reference object signal, using a real signal of a mixed signal as a desired signal, and canceling imaginary interference mixed in the mixed signal based on an adaptive interference cancellation algorithm;
extracting a real part signal of a reference signal as a reference object signal, an imaginary part signal of a mixed signal as a desired signal, and canceling imaginary part interference mixed in the mixed signal based on an adaptive interference cancellation algorithm; and
the real part signal of the reference signal is extracted as a reference object signal, the imaginary part signal of the mixed signal is taken as a desired signal, and the mixed signal is cancelled to mix in the imaginary part interference based on an adaptive interference cancellation algorithm.
7. A DVB-S2 signal demodulation method according to claim 6 wherein the adaptive filtering of the real and imaginary signals of the mixed signal is performed based on an adaptive filter.
8. A DVB-S2 signal demodulation apparatus comprising:
the down-conversion module is used for down-converting the radio frequency signal and the reference signal into intermediate frequency signals when receiving the radio frequency signal under the condition of same-frequency simultaneous interference; the frequency bands of the radio frequency signal and the reference signal are L frequency bands, and the reference signal is a local sequence signal;
the sampling module is used for respectively carrying out high-speed AD sampling processing on the two paths of intermediate frequency signals to obtain two paths of sampling signals, wherein the radio frequency signals correspond to the first sampling signals, and the reference signals correspond to the second sampling signals;
the synchronous module is used for carrying out data synchronous processing on the two paths of sampling signals by using an interference detection algorithm and a time delay estimation algorithm to obtain sampling signals corresponding to the radio frequency signals after time delay synchronization;
the frequency offset estimation module is used for estimating and correcting the sampling signals corresponding to the radio frequency signals after the time synchronization by using the frequency offset estimation algorithm and synchronously processing the timing deviation of the estimated and corrected sampling signals by using the timing recovery algorithm to obtain a mixed signal of the optimal sampling points;
the interference cancellation module is used for carrying out self-adaptive filtering processing on the real part signal and the imaginary part signal of the mixed signal by utilizing the real part signal and the imaginary part signal of the reference signal to obtain a digital signal;
and the demodulation module is used for demodulating and decoding the digital signal according to the communication protocol of the DVB-S2 signal to obtain the DVB-S2 signal.
9. The DVB-S2 signal demodulation device according to claim 8, wherein the sampling module is further specifically configured to perform high-speed AD sampling processing on the two paths of intermediate frequency signals by using low-pass sampling, so as to obtain two paths of 12-bit digital sampling signals.
10. A receiver comprising a DVB-S2 signal demodulation apparatus according to any one of claims 8 to 9.
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Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002230757A (en) * | 2001-02-05 | 2002-08-16 | Hitachi Ltd | Clock generating circuit and recording/reproducing device using the same |
| CN1407801A (en) * | 2001-08-28 | 2003-04-02 | 电子科技大学 | Synchronous multicarrier spread spectrum surface digital TV transmission system |
| US20090141841A1 (en) * | 2006-07-25 | 2009-06-04 | Fujitsu Limited | Interference noise estimation method, reception processing method, interference noise estimation apparatus, and receiver, in multicarrier communications system |
| US20130176877A1 (en) * | 2012-01-05 | 2013-07-11 | Qualcomm Incorporated | Detecting bursty interference to trigger a coexistence indication |
| CN105763498A (en) * | 2016-04-08 | 2016-07-13 | 南京理工大学 | All-digital receiving method for satellite-borne AIS |
| CN106101037A (en) * | 2016-06-17 | 2016-11-09 | 中国电子科技集团公司第十研究所 | The method that cross polarization interference offsets |
| CN108055103A (en) * | 2017-11-30 | 2018-05-18 | 西安空间无线电技术研究所 | A kind of anti-impulse disturbances method and system of TDMA system |
| KR20180063787A (en) * | 2016-12-02 | 2018-06-12 | 한국전자통신연구원 | Technology for removing interference and non-linearitu for signle satellite channel transmission based on dvb-s2 and dvb-rcs2 |
| CN110635890A (en) * | 2014-01-31 | 2019-12-31 | 苹果公司 | Reference subframes for synchronization and cell measurements |
| CN114584186A (en) * | 2022-03-02 | 2022-06-03 | 电子科技大学 | Polarization interference blind estimation and suppression method |
| WO2022247382A1 (en) * | 2021-05-25 | 2022-12-01 | 之江实验室 | Co-time co-frequency full-duplex signal receiving method |
-
2023
- 2023-03-09 CN CN202310225043.9A patent/CN116232436A/en active Pending
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002230757A (en) * | 2001-02-05 | 2002-08-16 | Hitachi Ltd | Clock generating circuit and recording/reproducing device using the same |
| CN1407801A (en) * | 2001-08-28 | 2003-04-02 | 电子科技大学 | Synchronous multicarrier spread spectrum surface digital TV transmission system |
| US20090141841A1 (en) * | 2006-07-25 | 2009-06-04 | Fujitsu Limited | Interference noise estimation method, reception processing method, interference noise estimation apparatus, and receiver, in multicarrier communications system |
| US20130176877A1 (en) * | 2012-01-05 | 2013-07-11 | Qualcomm Incorporated | Detecting bursty interference to trigger a coexistence indication |
| CN110635890A (en) * | 2014-01-31 | 2019-12-31 | 苹果公司 | Reference subframes for synchronization and cell measurements |
| CN105763498A (en) * | 2016-04-08 | 2016-07-13 | 南京理工大学 | All-digital receiving method for satellite-borne AIS |
| CN106101037A (en) * | 2016-06-17 | 2016-11-09 | 中国电子科技集团公司第十研究所 | The method that cross polarization interference offsets |
| KR20180063787A (en) * | 2016-12-02 | 2018-06-12 | 한국전자통신연구원 | Technology for removing interference and non-linearitu for signle satellite channel transmission based on dvb-s2 and dvb-rcs2 |
| CN108055103A (en) * | 2017-11-30 | 2018-05-18 | 西安空间无线电技术研究所 | A kind of anti-impulse disturbances method and system of TDMA system |
| WO2022247382A1 (en) * | 2021-05-25 | 2022-12-01 | 之江实验室 | Co-time co-frequency full-duplex signal receiving method |
| CN114584186A (en) * | 2022-03-02 | 2022-06-03 | 电子科技大学 | Polarization interference blind estimation and suppression method |
Non-Patent Citations (1)
| Title |
|---|
| 张超: "地面数字电视广播系统中前导符号的设计", 《2011国际传输与覆盖研讨会论文集》, 31 December 2011 (2011-12-31), pages 542 - 549 * |
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