CN107645466B - IQ independent processing method and device applied to satellite high-speed digital transmission system - Google Patents
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Abstract
The invention provides an IQ independent processing method applied to a satellite high-speed digital transmission system, which comprises the following steps: separating the received data frame into I, Q two paths of baseband signals; wherein the data frame comprises a data sequence and an auxiliary sequence positioned at a frame header; determining the output position of the auxiliary sequence according to the correlation peak positions of the I, Q two paths of baseband signals and the components of the standard auxiliary sequence in the I, Q two paths; respectively constructing I, Q two paths of first complex auxiliary sequences according to two adjacent real number symbols of the output auxiliary sequence; and respectively carrying out frequency offset estimation on the I, Q two paths of baseband signals according to the constructed first complex auxiliary sequence. The invention also provides an IQ independent processing device applied to the satellite high-speed digital transmission system. The invention meets the requirement of an IQ independent sampling ultra-high speed system, remarkably reduces the hardware requirement and the transmission overhead, and simultaneously keeps the system performance loss within an acceptable range.
Description
Technical Field
The invention relates to the technical field of electronics, in particular to an IQ independent processing method and device applied to a satellite high-speed digital transmission system.
Background
This section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. The description herein is not admitted to be prior art by inclusion in this section.
Satellite communication requires continuous improvement of data throughput, and under the condition that a modulation mode is limited, improvement of symbol rate is a main means. Increasing the symbol rate means an increase in the sampling rate of the baseband signal, and the sampling rate of the receiver ADC constitutes a bottleneck in the system performance. A satellite digital transmission system in design requires QPSK modulation to reach a 5G symbol rate, corresponding to a 10Gsps sampling rate, and can realize a single-path 10G ADC at most under the existing technical condition. Therefore, in the quadrature modulation scenario, two paths, I (inphase component) and Q (quadrature component), need to use two independent ADCs for sampling, and accordingly, a dedicated baseband structure needs to be designed. If the system is changed into IQ independent sampling and still uses the traditional baseband structure, on one hand, the bit rate of 10Gsps over-sampled data is extremely high, and the technology of combining two paths of data in real time is more difficult; on the other hand, two paths of sampling data come from independent ADCs, timing errors are different, and the sampling data cannot be combined as complex signals to carry out timing synchronization processing.
Disclosure of Invention
In view of the above, it is desirable to provide an IQ independent processing method and apparatus for a satellite high-speed digital transmission system, and the present invention is suitable for an application scenario in which IQ data is sampled by an independent ADC.
The invention provides an IQ independent processing method applied to a satellite high-speed digital transmission system, which comprises the following steps:
separating the received data frame into I, Q two paths of baseband signals; wherein the data frame comprises a data sequence and an auxiliary sequence positioned at a frame header;
determining the output position of the auxiliary sequence according to the correlation peak positions of the I, Q two paths of baseband signals and the components of the standard auxiliary sequence in the I, Q two paths;
respectively constructing I, Q two paths of first complex auxiliary sequences according to two adjacent real number symbols of the output auxiliary sequence;
and respectively carrying out frequency offset estimation on the I, Q two paths of baseband signals according to the constructed first complex auxiliary sequence.
Further, the auxiliary sequence is constructed by:
rotating each element of a segment of pseudorandom sequence by pi/2 in a complex number field to obtain a rotating sequence;
alternately arranging each element in the pseudo-random sequence and each element in the rotating sequence to obtain an auxiliary sequence unit;
and arranging a plurality of continuous auxiliary sequence units and then forming the auxiliary sequence by a sign-reversed auxiliary sequence unit.
Further, the determining the output position of the auxiliary sequence according to the correlation peak position of the I, Q two-way baseband signal and the component of the standard auxiliary sequence at I, Q two-way includes:
respectively carrying out sliding correlation on I, Q paths of baseband signals and components of the standard auxiliary sequence in I, Q paths;
and respectively determining the positions of the I, Q two paths of baseband signals for starting to output the captured data according to the maximum value of the obtained correlation result.
Further, the determining, according to the maximum value of the obtained correlation result, the positions where the I, Q two baseband signals start to output the captured data includes:
taking the length of the auxiliary sequence unit as a search unit to obtain the position of a correlation peak in each segment;
if the maximum values of the three continuous segments appear at the same position, the position of the I, Q two-path baseband signal for starting outputting the captured data is determined by the position of the last correlation peak respectively.
Further, frequency offset estimation is respectively performed on the I, Q paths of baseband signals by the following means:
wherein,
is frequency deviation; l is the length of the constructed auxiliary sequence; t issIs the symbol period of the transmission; r is2And r1Two consecutive first complex auxiliary sequences.
Further, after the separately performing frequency offset estimation on the I, Q two-way baseband signals according to the constructed first complex auxiliary sequence, the method further includes:
carrying out frame delimitation on the data frame to obtain the position where the data sequence starts to be output;
the I, Q two paths of baseband signals are respectively subjected to timing synchronization and down sampling through data output after frame delimitation;
performing data convergence on the I, Q two paths of baseband signals which are respectively subjected to down-sampling;
and carrying out frequency offset compensation, equalization and decoding on the converged data to obtain a recovered complex baseband information sequence.
Further, the frame delimiting the data frame to obtain a position where the data sequence starts to be output includes:
respectively constructing I, Q two paths of second complex auxiliary sequences according to two adjacent real number symbols of the output auxiliary sequence;
performing frequency offset compensation on the second complex auxiliary sequence to obtain a compensated complex auxiliary sequence;
segmenting the compensation complex auxiliary sequence to obtain a compensation complex auxiliary sequence unit;
correlating the compensated complex auxiliary sequence units of each segment with the auxiliary sequence units in sequence;
when the signs of the correlation values of two adjacent sections of the compensated complex auxiliary sequence units are opposite, data is output from the compensated complex auxiliary sequence unit of the next section.
Further, the compensated complex auxiliary sequence is obtained by:
wherein s is a compensation complex auxiliary sequence; r is a second complex auxiliary sequence; t issIs the symbol period of the transmission; Δ f is the frequency offset.
Further, the separately performing timing synchronization and down-sampling on the I, Q two paths of baseband signals includes:
obtaining an estimated timing error according to a correlation peak of data output under oversampling;
and compensating the timing error of the output data.
The present invention also provides an IQ-independent processing apparatus, comprising:
an IQ separation module, configured to separate a received data frame into I, Q two paths of baseband signals; wherein the data frame comprises a data sequence and an auxiliary sequence positioned at a frame header;
the acquisition module is used for determining the output position of the auxiliary sequence according to the correlation peak positions of the I, Q two paths of baseband signals and the components of the standard auxiliary sequence in the I, Q two paths;
the complex auxiliary sequence constructing module is used for respectively constructing I, Q two paths of first complex auxiliary sequences according to two adjacent real number symbols of the output auxiliary sequence;
and the frequency offset estimation module is used for respectively carrying out frequency offset estimation on the I, Q two paths of baseband signals according to the constructed first complex auxiliary sequence.
The IQ independent processing method applied to the satellite high-speed digital transmission system separates a received data frame into I, Q two paths of baseband signals; wherein the data frame comprises a data sequence and an auxiliary sequence positioned at a frame header; determining the output position of the auxiliary sequence according to the correlation peak positions of the I, Q two paths of baseband signals and the components of the standard auxiliary sequence in the I, Q two paths; respectively constructing I, Q two paths of first complex auxiliary sequences according to two adjacent real number symbols of the output auxiliary sequence; and respectively carrying out frequency offset estimation on the I, Q two paths of baseband signals according to the constructed first complex auxiliary sequence. The invention also provides an IQ independent processing device applied to the satellite high-speed digital transmission system. The invention meets the requirement of an IQ independent sampling ultra-high speed system, remarkably reduces the hardware requirement and the transmission overhead, and simultaneously keeps the system performance loss within an acceptable range.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a typical baseband processing architecture of a conventional digital receiver;
FIG. 2 is a diagram of a baseband architecture for use with the present invention;
FIG. 3 is a flow chart of the IQ independent processing method applied to the satellite high-speed digital transmission system according to the present invention;
fig. 4 is a schematic diagram of the data frame structure of the present invention.
Fig. 5 is a block diagram of a capture module of the present invention.
FIG. 6 is a timing error estimation schematic of the present invention;
FIG. 7 is a functional block diagram of an exemplary IQ independent processing apparatus for a satellite high-speed digital transmission system according to the present invention;
fig. 8 is a schematic diagram comparing the bit error rate curves of the present invention and a conventional baseband processing architecture.
Description of the main elements
| Device for measuring the position of a moving |
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| Plural auxiliary |
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| Frequency offset |
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| Timing synchronization and |
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The following detailed description will further illustrate the invention in conjunction with the above-described figures.
Detailed Description
In order that the above objects, features and advantages of the present invention can be more clearly understood, a detailed description of the present invention will be given below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.
In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention, and the described embodiments are merely a subset of the embodiments of the present invention, rather than a complete embodiment. 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.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
A typical baseband processing structure of the conventional digital receiver can be shown in fig. 1, where timing synchronization shown in fig. 1 and previous parts process oversampled data, but if the system changes to IQ independent sampling and still uses the above baseband structure, it is difficult to combine two paths of data because the bit rate of the oversampled data is very high, and the two paths of sampled data come from independent ADCs, and the timing errors are different, so that timing synchronization cannot be performed as complex signal combination.
The IQ independent processing method applied to the satellite high-speed digital transmission system is suitable for application scenes that IQ two paths use independent ADCs to carry out sampling, can enable the IQ two paths to independently carry out processing before timing synchronization, can obviously reduce hardware requirements and transmission overhead, and simultaneously keeps system performance loss within an acceptable range.
The structure diagram of the baseband used in the present invention can be as shown in fig. 2, the signal source is transmitted to the receiving end through radio frequency after adding the auxiliary sequence and framing at the transmitting end, the receiving end separates the data frame into I, Q two paths of baseband signals after receiving through radio frequency, and the separated I, Q two paths of baseband signals are processed by the same independent processing module respectively and then merged to obtain the conventional complex baseband signal.
As shown in fig. 3, an embodiment of the present invention provides an IQ-independent processing method for a satellite high-speed digital transmission system, which may include the following steps:
s1: separating the received data frame into I, Q two paths of baseband signals; wherein the data frame comprises a data sequence and an auxiliary sequence located at a frame header.
In this step S1, after the data frame is separated into I, Q two baseband signals, the I baseband signal can only obtain information of the real part, the Q baseband signal can only obtain information of the imaginary part, but both the frequency offset estimation and the timing synchronization require an auxiliary sequence of complex symbols, so in this embodiment, an auxiliary sequence is set at the header of the data frame, and an approximate complex sequence is constructed by the information of the auxiliary sequence in the I and Q channels, respectively.
Wherein, the auxiliary sequence can be constructed by adopting the following method:
taking a segment of pseudorandom sequence with the length of L and marking the segment as A; rotating each element of A by pi/2 in a complex number field to obtain a sequence which is a rotating sequence and is marked as B; then the elements of a and B have a correspondence:
according to the corresponding relation, the following can be obtained:
Re{B(k)}＝-Im{A(k)}
Im{B(k)}＝Re{A(k)}
where k is 1, 2, …, L.
And (2) alternately arranging the elements of A and B to obtain a sequence X, wherein the sequence X is an auxiliary sequence unit used in the invention, and the structure of the sequence X is as follows:
X＝{A(1)B(1)A(2)B(2)}...A(L)B(L)}
the auxiliary sequence includes a plurality of segments of sequence X, and specifically may include 16 consecutive segments of sequence X followed by a segment of sequence-X, where the sequence-X is a symbol-reversed sequence X, and the auxiliary sequence may be as shown in fig. 4, and may be followed by another auxiliary sequence followed by a data sequence, where the other auxiliary sequence may include another auxiliary sequence used in the channel estimation field, and a header of each data sequence block of the data sequence has a shorter auxiliary sequence, and the sequence uses a common pseudo-random sequence, and is called sequence Y without using the above-mentioned construction method, and the sequence Y is used for assisting timing synchronization.
S2: and determining the output position of the auxiliary sequence according to the correlation peak positions of the I, Q two paths of baseband signals and the components of the standard auxiliary sequence in the I, Q two paths.
This step is performed in the capture module in fig. 2, which may be specifically as shown in fig. 5, and the Q-way and the I-way are processed in the same way, which is described in detail below by taking the I-way as an example.
This step S2 is a capturing step, and the basic principle of the capturing is that the received signal is slide-correlated with the auxiliary sequence, and the frame header position of the data frame is determined by finding the position of the correlation peak.
The structure of the capturing module can be as shown in fig. 5, I-path baseband signals are input into a correlator, correlated with components of the standard auxiliary sequence in the I path, the correlation results are sent into a maximum value searching unit, the maximum value searching unit adopts a maximum value position confirmation processing method, and the positions of I, Q two paths of baseband signals at which the captured data starts to be output are respectively determined according to the maximum values of the obtained correlation results.
Specifically, a method of confirming the maximum position may be adopted for multiple times, and the following method may be adopted: and taking the sequence X of the auxiliary sequence as a search unit, searching to obtain the position of the maximum value in each segment, considering that the acquisition is successful if the maximum values of three continuous segments appear at the same position, determining the starting position of the next auxiliary sequence by using the position of the last correlation peak, and outputting the acquired auxiliary sequence data from the starting position, wherein the step can use 4 segments of the sequence X at most.
S3: and respectively constructing I, Q two paths of first complex auxiliary sequences according to two adjacent real number symbols of the output auxiliary sequence.
The first complex auxiliary sequence of I, Q branches can be constructed from the projections of the auxiliary sequence at I, Q branches.
According to the method for constructing the auxiliary sequence in step S1, the following relationship holds for the projection of the sequence X on one path:
A(k)＝Re{X(2k-1)}-jRe{X(2k)}＝Re{A(k)}-jRe{B(k)} ＝Re{A(k)}+jIm{A(k)}
A(k)＝Im{X(2k)}+jIm{X(2k-1)}＝Im{B(k)}+jIm{A(k)} ＝Re{A(k)}+jIm{A(k)}
therefore, a complex auxiliary sequence symbol can be constructed by two adjacent real symbols of the I-path according to the above relationship.
In practical application, a received signal is affected by frequency offset and the like, the phase difference of adjacent symbols is not accurate 90 degrees, and the above relation cannot be accurately established; however, in most systems, the phase difference between adjacent symbols due to frequency offset or the like is small, and the above-described construction method can be used approximately.
S4: and respectively carrying out frequency offset estimation on the I, Q two paths of baseband signals according to the constructed first complex auxiliary sequence.
Let the constructed two consecutive auxiliary sequences be r1And r2Then, the following relationship exists between the two auxiliary sequences:
wherein Δ f is a frequency offset, i.e., an amount to be estimated; l is the length of the constructed helper sequence; t issIs the symbol period of the transmission. Get 2T from the above formulasSince two transmitted symbols constitute one auxiliary sequence symbol; n is2Is noise.
According to the above relation, the frequency offset estimation value can be obtained as follows:
affected by phase folding, the frequency deviation estimation range of the algorithm is +/-1/(2 LT)s) In the meantime, increasing L limits the estimation range of the frequency offset, but reduces the estimation variance; and vice versa.
The obtained frequency deviation estimated value can be used as a parameter of frequency deviation compensation when being sent to the subsequent IQ combination processing.
The IQ-independent processing method according to the present embodiment may further include, after step S4, the steps of:
s5: and carrying out frame delimitation on the data frame to obtain the position where the data sequence starts to be output.
The main purpose of frame delineation is to search for the position of sequence-X in the auxiliary sequence to determine the starting point of the subsequent frame structure.
The frame delimitation method can adopt the following modes:
s51: and respectively constructing I, Q two paths of second complex auxiliary sequences according to two adjacent real number symbols of the output auxiliary sequence.
The method for constructing the second complex auxiliary sequence can be implemented by the method in step S3, and the constructed sequence is designated as r.
S52: and performing frequency offset compensation on the second complex auxiliary sequence to obtain a compensated complex auxiliary sequence.
The compensated complex auxiliary sequence obtained here is S, the frequency offset compensation in step S52 is a frequency offset to the second complex auxiliary sequence, and the correlation between the compensated complex auxiliary sequence S and the second complex auxiliary sequence r is:
s53: and segmenting the compensated complex auxiliary sequence to obtain a compensated complex auxiliary sequence unit.
The sequence output from the acquisition module is aligned with the auxiliary sequence, and the compensated complex auxiliary sequence s is segmented by length L.
S54: correlating the compensated complex auxiliary sequence units of each segment in turn with the auxiliary sequence units.
S55: when the signs of the correlation values of two adjacent sections of the compensated complex auxiliary sequence units are opposite, data is output from the compensated complex auxiliary sequence unit of the next section.
When the signs of the correlation values of the two adjacent sections are opposite, the latter section is considered as a sequence-X, so that a delimiting position in the sequence s can be found, the position is corresponding to the position in the input data, and the data is output from the compensated complex auxiliary sequence unit of the latter section.
S6: and respectively carrying out timing synchronization and down sampling on the I, Q two paths of baseband signals by data output after frame delimitation.
In step S6, timing synchronization processing is first performed. The timing synchronization process is to process the sampling point offset at the transmitting and receiving ends, and obtain the timing error by using the extra information provided by the over-sampled data, and in step S6 of the present embodiment, the pseudo-random sequence at the head of the data sequence block and the components in sequence Y in two paths I, Q are correlated to obtain the estimated value of the timing error.
Specifically, under the double oversampling, the autocorrelation peak of the pseudo random sequence at the head of each data sequence block is approximated to an isosceles triangle, and the estimated value of the timing error can be calculated by using the symmetry of the isosceles triangle and the trigonometric function relationship, as shown in fig. 6.
As shown in fig. 6, the timing offset has little effect on the use of three samples, and the interval between adjacent samples can be considered to be still equal to one standard sampling period.
The length of the bottom edge of the triangle of the correlation peak is 4 sampling periods, and the correlation peak has the following relationship according to the triangle:
RG(1)+RG(-1)＝-2tanθ
RG(1)-RG(-1)＝-2μtanθ
where θ is the base angle of an isosceles triangle, R is shown in formula (II) and in FIG. 6G(-1) is the correlation peak of the first sample point, RG(0) For the second sample point correlation peak, RG(1) The third sample correlation peak, μ is the timing error.
From the above relationship, the timing error can be found:
each data sequence block performs a timing error estimation to track slow variations of timing error.
In step S6, a correlation peak threshold detection procedure may be additionally added, the correlation peak value of each data block is compared with a threshold, and if the correlation peak is too low, the estimated value of the data sequence block may be discarded, and the timing error of the discarded data sequence block is set to 0.
In step S6, timing error compensation is performed after the timing synchronization process is performed.
The timing error compensation can adopt a Farrow interpolation method, and the interpolation coefficients are respectively as follows:
C-2＝αμ2-αμ
C-1＝-αμ2+(α+1)μ
C0＝αμ2+(α-1)μ+ 1
C1＝αμ2-αμ
assuming that the input sequence is r, for the symbol with the main sampling point r (k), the interpolation result is:
s(k)＝C-2r(k-2)+C-1r(k-1)+C0r(k)+C1r(k+1)
s7: and performing data convergence on the I, Q two paths of baseband signals respectively subjected to down-sampling.
S8: and carrying out frequency offset compensation, equalization and decoding on the converged data to obtain a recovered complex baseband information sequence.
When the frequency offset compensation is performed on the converged data, the frequency offset estimation parameters calculated in step S4 may be input to a frequency offset compensation module, and frequency offset compensation is performed when the IQ combining is processed according to the frequency offset estimation parameters, and the data after frequency offset compensation is successively sent to a conventional equalization unit and a decoding unit, so as to obtain a recovered complex baseband information sequence.
The present invention further provides an IQ-independent processing apparatus 100 applied to a satellite high-speed digital transmission system, as shown in fig. 7, the IQ-independent processing apparatus may include an IQ separation module 1, a capture module 2, a complex auxiliary sequence construction module 3, and a frequency offset estimation module 4, wherein:
the IQ separation module 1 is configured to separate a received data frame into I, Q two paths of baseband signals; wherein the data frame comprises a data sequence and an auxiliary sequence positioned at a frame header;
the capturing module 2 is configured to determine an output position of the auxiliary sequence according to the correlation peak positions of the I, Q two paths of baseband signals and components of the standard auxiliary sequence in the I, Q two paths;
the complex auxiliary sequence constructing module 3 is configured to respectively construct I, Q two paths of first complex auxiliary sequences according to two adjacent real number symbols of the output auxiliary sequence;
and the frequency offset estimation module 4 is configured to perform frequency offset estimation on the I, Q two paths of baseband signals respectively according to the constructed first complex auxiliary sequence.
The IQ-independent processing apparatus may further include a frame delimitation module 5, a timing synchronization and down-sampling module 6, an IQ merging module 7, and a post-processing module 8, wherein:
the frame delimitation module 5 is configured to perform frame delimitation on the data frame after performing frequency offset estimation on the I, Q two baseband signals, respectively, to obtain a position where the data sequence starts to be output;
the timing synchronization and down-sampling module 6 is configured to perform timing synchronization and down-sampling on the I, Q two paths of baseband signals respectively through data output after frame delimitation;
the IQ convergence module 7 is configured to perform data convergence on the I, Q two paths of baseband signals respectively subjected to down-sampling;
and the post-processing module 8 is configured to perform frequency offset compensation, equalization and decoding on the converged data to obtain a recovered complex baseband information sequence.
The invention separates the received data frame into I, Q two paths of baseband signals to carry out IQ independent processing, and can construct complex auxiliary sequence when only one path of data in IQ is available, thus IQ can independently carry out baseband processing such as frequency deviation estimation, frequency deviation recovery and frame delimitation, IQ independently carries out baseband processing steps as many as possible, thereby maximizing the improvement of IQ independent processing structure to system efficiency.
Under the simulation parameters in table 1, the error rate curves of the present embodiment and the conventional baseband processing structure are compared with an illustration 8, where the curves are divided into two groups, the first group is a reference case, that is, only white noise (no frequency offset and timing error) exists, and the error rate difference between the two structures is very small, which indicates that the additional performance loss caused by the structure of the present invention is very small. The second group is non-ideal, with severe carrier frequency offset and timing error, at which point the performance of the invention is at a certain distance from the conventional structure, about 2.5dB, within the usable range. In summary, the present invention provides a feasible method for doubling the system symbol rate at the expense of acceptable performance loss.
TABLE 1 bit error Rate simulation parameters
| Item | Value of |
| Symbol rate | 5GHz |
| Modulation system | |
| Over-sampling rate | |
| 2 | |
| Coding method | |
| Coding efficiency | |
| 3/4 | |
| Carrier frequency | 60G |
| Carrier frequency offset | 10ppm |
| Timing frequency offset | 10ppm |
| Channel with a plurality of channels | AWGN |
In the several embodiments provided in the present invention, it should be understood that the method and apparatus may also be implemented in other manners, the above-described apparatus embodiments are only illustrative, the division of the modules is only one logical function division, and there may be other division manners when implemented.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned. Furthermore, it is obvious that the word "comprising" does not exclude other elements or steps, and the singular does not exclude the plural. Several of the means recited in the apparatus claims may also be embodied by one and the same means or system in software or hardware. The terms first, second, etc. are used to denote names, but not any particular order.
Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (9)
1. A method for IQ-independent processing for a satellite high-speed digital transmission system, the method comprising:
separating the received data frame into I, Q two paths of baseband signals; wherein the data frame comprises a data sequence and an auxiliary sequence positioned at a frame header;
determining the output position of the auxiliary sequence according to the I, Q two paths of baseband signals and the correlation peak positions of the components of the auxiliary sequence units in I, Q two paths, wherein a plurality of continuous auxiliary sequence units are arranged and then are followed by an auxiliary sequence unit with reversed sign to form the auxiliary sequence;
respectively constructing I, Q two paths of first complex auxiliary sequences according to two adjacent real number symbols of the output auxiliary sequence;
respectively carrying out frequency offset estimation on the I, Q two paths of baseband signals according to the constructed first complex auxiliary sequence;
carrying out frame delimitation on the data frame to obtain the position where the data sequence starts to be output;
the I, Q two paths of baseband signals are respectively subjected to timing synchronization and down sampling through data output after frame delimitation;
performing data convergence on the I, Q two paths of baseband signals which are respectively subjected to down-sampling;
and carrying out frequency offset compensation, equalization and decoding on the converged data to obtain a recovered complex baseband information sequence.
2. The IQ-independent processing for a satellite high-speed digital transmission system according to claim 1, characterized in that the auxiliary sequence unit is constructed by:
rotating each element of a segment of pseudorandom sequence by pi/2 in a complex number field to obtain a rotating sequence;
and alternately arranging each element in the pseudo-random sequence and each element in the rotating sequence to obtain an auxiliary sequence unit.
3. The IQ independent processing method for satellite high-speed digital transmission system according to claim 2, wherein the determining the output position of the auxiliary sequence according to the correlation peak position of the I, Q two-way baseband signal and the component of the auxiliary sequence unit in I, Q two-way comprises:
respectively carrying out sliding correlation on I, Q paths of baseband signals and components of the auxiliary sequence unit in I, Q paths;
and respectively determining the positions of the I, Q two paths of baseband signals for starting to output the captured data according to the maximum value of the obtained correlation result.
4. The IQ independent processing method for satellite high-speed digital transmission system according to claim 3, wherein the determining the positions where the I, Q two-path baseband signals start to output the captured data according to the maximum value of the obtained correlation results comprises:
taking the length of the auxiliary sequence unit as a search unit to obtain the position of a correlation peak in each segment;
if the maximum values of the three continuous segments appear at the same position, the position of the I, Q two-path baseband signal for starting outputting the captured data is determined by the position of the last correlation peak respectively.
5. The IQ-independent processing method for satellite high-speed digital transmission system according to claim 1 or 2, wherein the I, Q two-path baseband signals are respectively frequency offset estimated by:
wherein,
is frequency deviation; l is the length of the constructed auxiliary sequence; t issIs the symbol period of the transmission; r is2And r1Two consecutive first complex auxiliary sequences.
6. The IQ-independent processing method for satellite high-speed digital transmission systems according to claim 1, wherein the frame-delimiting the data frames to obtain the position where the data sequence starts to be output comprises:
respectively constructing I, Q two paths of second complex auxiliary sequences according to two adjacent real number symbols of the output auxiliary sequence;
performing frequency offset compensation on the second complex auxiliary sequence to obtain a compensated complex auxiliary sequence;
segmenting the compensation complex auxiliary sequence to obtain a compensation complex auxiliary sequence unit;
correlating the compensated complex auxiliary sequence units of each segment with the auxiliary sequence units in sequence;
when the signs of the correlation values of two adjacent sections of the compensated complex auxiliary sequence units are opposite, data is output from the compensated complex auxiliary sequence unit of the next section.
7. The IQ-independent processing method for satellite high-speed digital transmission systems according to claim 1, wherein the compensated complex auxiliary sequence is obtained by:
wherein s is a compensation complex auxiliary sequence; r is a second complex auxiliary sequence; t issIs the symbol period of the transmission; Δ f is the frequency offset.
8. The IQ-independent processing method for satellite high-speed digital transmission system according to claim 1, wherein the separately timing-synchronizing and down-sampling the I, Q two baseband signals comprises:
obtaining an estimated timing error according to a correlation peak of data output under oversampling;
and compensating the timing error of the output data.
9. An apparatus for IQ-independent processing for a satellite high-speed digital transmission system, the apparatus comprising:
an IQ separation module, configured to separate a received data frame into I, Q two paths of baseband signals; wherein the data frame comprises a data sequence and an auxiliary sequence positioned at a frame header;
the acquisition module is used for determining the output position of the auxiliary sequence according to the correlation peak positions of the I, Q two paths of baseband signals and components of the auxiliary sequence unit in I, Q two paths, wherein a plurality of continuous sections of the auxiliary sequence units are arranged and then are connected with an auxiliary sequence unit with reversed sign to form the auxiliary sequence;
the complex auxiliary sequence constructing module is used for respectively constructing I, Q two paths of first complex auxiliary sequences according to two adjacent real number symbols of the output auxiliary sequence;
the frequency offset estimation module is used for respectively carrying out frequency offset estimation on the I, Q two paths of baseband signals according to the constructed first complex auxiliary sequence;
the frame delimitation module is used for performing frame delimitation on the data frame to obtain the position where the data sequence starts to be output;
the timing synchronization and down-sampling module is used for respectively performing timing synchronization and down-sampling on the I, Q two paths of baseband signals through data output after frame delimitation;
the IQ convergence module is used for carrying out data convergence on the I, Q two paths of baseband signals which are respectively subjected to down-sampling;
and the post-processing module is used for carrying out frequency offset compensation, equalization and decoding on the converged data to obtain a recovered complex baseband information sequence.
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