Burst signal processing method, processing system, electronic equipment and medium

Abstract

The present application discloses a burst signal processing method, processing system, electronic device and medium, the processing method comprising: shifting a received burst signal to obtain multiple groups of shifted signals; the burst signal comprises a unique word; obtaining multiple groups of first signals according to the multiple groups of shifted signals and a local unique word sequence; obtaining a first value according to adjacent data in the multiple groups of first signals; and processing the burst signal according to the first value. The present application can reduce complexity and can complete frequency offset estimation while completing detection.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a burst signal processing method, processing system, electronic equipment and medium. Background Art

[0002] Existing technologies solve the detection and synchronization of burst communications in low Doppler shift scenarios, and can better meet common ground application scenarios, such as GNSS (Global Navigation Satellite system) satellites. Due to the slow speed of movement to the ground, the Doppler shift is usually below 10KHz. Relatively speaking, LEO (Low Earth Orbit) satellites have a lower orbit and a greatly increased speed of movement to the ground, resulting in increased Doppler shift and rapid changes in signal-to-noise ratio. Current technologies face great challenges in detecting and synchronizing burst communication signals, especially in low signal-to-noise ratio conditions. Summary of the invention

[0003] In view of this, the present application provides a burst signal processing method, processing system, electronic device and medium, which mainly solve the signal detection and frequency offset estimation problems of ground wireless communication equipment under large Doppler frequency shift conditions, and optimize traditional algorithms.

[0004] The present application discloses a burst signal processing method, which comprises:

[0005] Shifting the received burst signal to obtain multiple groups of shifted signals; the burst signal includes a unique word;

[0006] Obtaining multiple groups of first signals according to the multiple groups of shift signals and local unique word sequences;

[0007] Obtaining a first value according to adjacent data in the plurality of groups of first signals;

[0008] The burst signal is processed according to the first value.

[0009] Further, the processing the burst signal according to the first value includes:

[0010] Determining whether the burst signal is detected according to the first value and a preset threshold;

[0011] If the burst signal is detected, a frequency offset estimation result of the burst signal is obtained.

[0012] Furthermore, the received burst signal is shifted to obtain multiple groups of shifted signals, including:

[0013] Sampling the received burst signal to obtain a sampled signal;

[0014] The sampling signal is shifted to obtain multiple groups of shifted signals.

[0015] Further, the obtaining of multiple groups of first signals according to the multiple groups of shift signals and local unique word sequences comprises:

[0016] Each group of the shifted signals in the plurality of groups of shifted signals is correspondingly multiplied with each local unique word in the local unique word sequence to obtain a plurality of groups of first signals; each group of the shifted signals corresponds one-to-one to each local unique word.

[0017] Further, obtaining the first value according to the adjacent data in the plurality of groups of first signals includes:

[0018] Adjacent bits in the plurality of groups of first signals are sequentially differentially conjugated and multiplied to obtain a first value.

[0019] Further, judging whether the burst signal is detected according to the first value and a preset threshold includes:

[0020] Calculate the average value of the first value, and extract the envelope square of the average value;

[0021] Dividing the envelope square by the signal power of the burst signal to obtain a second value;

[0022] The second value is compared with a preset threshold to determine whether the burst signal is detected.

[0023] Further, comparing the second value with a preset threshold to determine whether the burst signal is detected includes:

[0024] If the second value is greater than a preset threshold, it indicates that the burst signal has been detected.

[0025] Further, obtaining a frequency offset estimation result of the burst signal includes:

[0026] Calculate an average value of the first values, and calculate a first argument principal value of the average value;

[0027] Obtaining a third value according to adjacent bits in the first value;

[0028] A frequency offset estimation result is obtained according to the first argument principal value and the third value; the frequency offset estimation result includes an estimated value of frequency acceleration and an estimated value of frequency offset.

[0029] Further, obtaining a third value according to adjacent bits in the first value includes:

[0030] Adjacent bits in the first value are sequentially differentially conjugate multiplied to obtain a third value.

[0031] Further, obtaining a frequency offset estimation result according to the first argument principal value and the third value includes:

[0032] Calculating an average value of the third values;

[0033] Obtaining a second argument principal value of the average value of the third value;

[0034] Obtaining an estimated value of the frequency acceleration according to the second argument principal value;

[0035] An estimated value of the frequency offset is obtained according to the first argument principal value and the second argument principal value.

[0036] The present application also discloses a burst signal processing system, which comprises:

[0037] A shift module, used for shifting the received burst signal to obtain multiple groups of shifted signals; the burst signal includes a unique word;

[0038] A first calculation module, configured to obtain a plurality of groups of first signals according to the plurality of groups of shift signals and local unique word sequences;

[0039] A second calculation module, configured to obtain a first value according to adjacent data in the plurality of groups of first signals;

[0040] A burst signal processing module is used to process the burst signal according to the first value.

[0041] The present application also discloses an electronic device, which includes a memory and a processor. The memory stores a computer program, and the computer program implements the above-mentioned burst signal processing method when executed by the processor.

[0042] The present application also discloses a computer-readable storage medium, which includes a computer program or instructions. When the computer program or instructions are executed on a computer, the computer executes the above-mentioned burst signal processing method.

[0043] Due to the adoption of the above technical solution, the present application has the following advantages: the present application can utilize the high-performance UW (Unique Word) for signal detection and frequency offset estimation, thereby reducing the complexity of burst signal processing and completing frequency offset estimation while completing burst signal detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0045] Figure 1 A schematic diagram of a burst data format according to an embodiment of the present application;

[0046] Figure 2 A schematic diagram of a signal detection solution based on a digital matched filter according to an embodiment of the present application;

[0047] Figure 3 A schematic diagram of a signal detection solution based on digital matched filter sample point difference according to an embodiment of the present application;

[0048] Figure 4 A schematic diagram of a frequency offset estimation algorithm according to an embodiment of the present application;

[0049] Figure 5 A schematic diagram of a flow chart of a burst signal processing method according to an embodiment of the present application;

[0050] Figure 6 A block diagram of a burst signal processing system according to an embodiment of the present application;

[0051] Figure 7 A block diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0052] The present application is further described in conjunction with the accompanying drawings and embodiments, and the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field should fall within the scope of protection of the embodiments of the present application.

[0053] In the prior art, the sliding window method and the digital matched filter method are usually used for signal detection. Among them, the sliding window method does not fully utilize the unique word to detect low signal-to-noise ratio signals and estimate frequency deviation. The digital matched filter method and the sliding correlation algorithm reflect the different exchange of resource overhead and capture speed. The matched filter algorithm is more inclined to capture speed and is very suitable for digital implementation.

[0054] Since the above-mentioned prior art has the problems described in the background technology, the embodiments of the present application provide a burst signal processing method, processing system, electronic device and medium. Figure 1 As shown in FIG. 1 , a satellite Internet navigation enhancement signal burst data format includes multiple parts such as a protection interval, a unique word, and navigation enhancement data. Among them, the unique word length is symbols, BPSK modulation can be used. In burst mode, the receiver must first perform start detection on the received data packet, that is, burst signal detection. Since the frequency deviation of the low-orbit satellite landing signal is large, signal detection and frequency deviation estimation are very difficult, especially when the received signal-to-noise ratio is very low. From the perspective of the burst data format, the unique word is a known sequence at the receiving end and can be used for signal detection and frequency deviation estimation.

[0055] To ensure the real-time performance of signal detection, the following methods can be used: Figure 2 The length shown is Assume the symbol rate is , is the oversampling factor, then the sampling rate Received data sampling point Enter the length of Each of the The bit register output is a group, each group is associated with a local unique word Multiply the corresponding bits to get Then the multiplication output Results Find the average and take the square of its envelope , and then divided by the signal power before correlation , the results obtained and threshold Compare. If greater than , it indicates that the signal is detected. If it is less than , it means that no signal is detected, and the new data sample point is input into the shift register, which is equivalent to the data in the register sliding one bit as a whole, and then repeating the previous operation.

[0056] In the case of large frequency deviation, Figure 2 The detection peak of the corresponding basic solution is not obvious, and it is easy to miss the detection, especially for the large Doppler frequency shift scenario of the low-orbit satellite system, the signal detection effect is not good. In view of this, see Figure 5 , an embodiment of the present application provides a burst signal processing method, which includes:

[0057] Step 501: Shift the received burst signal to obtain multiple groups of shifted signals; the burst signal includes a unique word, such as Figure 1 As shown;

[0058] In one embodiment of the present application, the received burst signal may be sampled to obtain a sampled signal; and the sampled signal may be shifted to obtain multiple groups of shifted signals.

[0059] In one possible implementation, assuming the symbol rate is , is the oversampling factor, then the sampling rate , sample the received burst signal and obtain the sampled signal ; The sampling signal can be Enter the length of The shift register (each The bit register output is a group, a total of L groups), output L groups of shift signals, and the L groups of shift signals can be expressed as , ,..., ;in, is the shift signal output by the first group of shift registers, is the shift signal output by the second group of shift registers, It is the shift signal output by the Lth group of shift registers.

[0060] Step 502, obtaining a plurality of first signals according to a plurality of shift signals and a local unique word sequence;

[0061] In one embodiment of the present application, each group of shifted signals in the multiple groups of shifted signals can be multiplied with each local unique word in the modulated local unique word sequence to obtain multiple groups of first signals; each group of shifted signals corresponds to each local unique word one by one.

[0062] In a possible implementation, based on the implementation of step 501, see Figure 3 In order to minimize the impact of large frequency deviation on signal detection performance, each group of shifted signals is respectively combined with the local unique word sequence after modulation (such as BPSK modulation) The corresponding bits are multiplied, and after multiplication, L groups of first signals are output respectively. For example, the first group of shifted signals The N bits of data (a total of N bits) are respectively modulated with the local unique word sequence The Lth local unique word in Multiply them together to get the first group of first signals, expressed as ; The second set of shift signals The N bits of data (a total of N bits) are respectively modulated with the local unique word sequence The L-1th local unique word in Multiply them together to get the second set of first signals, expressed as ; And so on, we get the third group of first signals , ..., the first signal of group L .

[0063] Step 503, obtaining a first value according to the adjacent data in the plurality of groups of first signals;

[0064] In one embodiment of the present application, adjacent bits in multiple groups of first signals may be differentially conjugate multiplied in sequence to obtain a first value.

[0065] In a possible implementation, based on the implementation of step 502, taking two adjacent bits in the first group of first signals as an example, that is, two adjacent bits in the first group of first signals are and Difference conjugate multiplication to obtain After performing differential conjugate multiplication on every two adjacent bits in the plurality of groups of first signals (which may be composed of the first group of first signals to the Lth group of first signals arranged in sequence), a first value is obtained, that is, , ,..., ,common 1 output.

[0066] Step 504: Process the burst signal according to the first value.

[0067] In one embodiment of the present application, a burst signal is processed according to a first value, including: judging whether a burst signal is detected according to the first value and a preset threshold; if a burst signal is detected, obtaining a frequency deviation estimation result of the burst signal.

[0068] In one embodiment of the present application, judging whether a burst signal is detected is performed based on a first value and a preset threshold, including: calculating an average value of the first value and extracting an envelope square of the average value; dividing the envelope square by the signal power of the burst signal to obtain a second value; if the second value is greater than the preset threshold, it indicates that a burst signal has been detected, otherwise no burst signal has been detected.

[0069] In a possible implementation, based on the implementation of step 503, the average value of the first value is calculated, and then the envelope square is taken out from the average value, and then the envelope square is divided by the sampling signal of the burst signal. Signal power , the result obtained With threshold Compare. If greater than , it indicates that the burst signal has arrived. If it is less than , it means that no burst signal is detected, and the new data sample point (sampling signal) is input into the shift register, which is equivalent to the data in the register sliding one bit as a whole, and then repeating the previous operation.

[0070] This embodiment solves the problem that satellite Internet equipment cannot complete the detection and synchronization of burst communications well under large Doppler frequency shift and low signal-to-noise ratio by combining a digital matched filter and an adaptive threshold correlation detection algorithm, so that the equipment can complete the detection and rapid synchronization of burst communications under large Doppler frequency shift and low signal-to-noise ratio.

[0071] Alternatively, assume that the unique word sequence is .make and represents the frequency deviation and initial phase of the received signal, is the frequency acceleration of the received signal, represents the sampling time, then The received signal at a certain moment It can be expressed as:

[0072]

[0073] in, is the amplitude of the received signal, Unique word sequence modulated (e.g. BPSK modulation) and The symbol sequence after times oversampling, is noise and follows a standard Gaussian distribution.

[0074] As a unique word known at the receiving end, that is It is known at the receiving end. Signal samples of the stage shift register With local When the received signal is multiplied by the local In the case of perfect alignment, we get:

[0075] (1)

[0076] in, The noise still obeys the standard Gaussian distribution. and By multiplying the difference conjugates in sequence, we can get:

[0077] (2)

[0078] It can be seen that except for the first term, the following three terms are noise terms and still obey the Gaussian distribution with a mean of 0. indivual By averaging to eliminate the influence of noise, we can get:

[0079]

[0080] Due to the acceleration of the aircraft, Usually less than 300Hz / s; is the system sampling period, Greater than 4.096MHz, therefore, .

[0081] Combined with the knowledge of mathematical limits, we can know that , we can get:

[0082]

[0083]

[0084] The above formula is simplified to:

[0085] (3)

[0086] in, The noise is still Gaussian distributed. Ignore the influence of noise and modulo the above formula to get:

[0087]

[0088] Therefore, when the received signal is not completely aligned with the local unique word sequence, It cannot be offset, so the result of subsequent operations is equivalent to the noise signal; when the received signal is completely aligned with the local unique word sequence, the above algorithm can obtain a clear peak , so the arrival of the signal can be detected by setting a suitable threshold. In addition, the size of the peak value is only related to the adjacent The signal detection performance is reduced by reducing the influence of large frequency deviation on the signal detection performance.

[0089] In view of the problem that existing satellite Internet equipment cannot adapt well to large Doppler frequency shift, a digital matched filter is designed. By using the modulus operation, the peak value of the correlation peak is not obvious due to the large frequency deviation, and the start detection of burst communication is completed. The adaptive threshold correlation detection algorithm is introduced to solve the problem of signal-to-noise ratio changes during the transit of low-orbit satellites, and the correct frequency deviation estimation can be obtained under low signal-to-noise ratio (for example, the ratio of bit energy Eb to noise power spectrum density N0 is equal to 5dB).

[0090] From the data format of burst communication, the unique word can be used as a known sequence at the receiving end to estimate the frequency offset. Considering that the unique word has been used for burst signal detection, frequency offset estimation and signal detection should be performed simultaneously. Once a burst signal is detected, the frequency offset estimation result (including frequency acceleration estimation) can be output synchronously.

[0091] Optionally, obtaining a frequency offset estimation result of the burst signal includes:

[0092] In one embodiment of the present application, an average value of the first value can be calculated, and a first principal angular value of the average value can be calculated; adjacent bits in the first value are differentially conjugate multiplied in sequence to obtain a third value, thereby eliminating the problem of phase flipping in modulation (such as BPSK modulation); an average value of the third value is calculated; a second principal angular value of the average value is obtained; based on the second principal angular value, an estimated value of the frequency acceleration is obtained; and based on the first principal angular value and the second principal angular value, an estimated value of the frequency deviation is obtained.

[0093] See also Figure 4 Based on the above embodiment, the influence of noise can be ignored and the four-quadrant inverse tangent of equation (3) can be calculated, so as to have a larger phase detection range, and the main value of the argument (the first main value of the argument) can be obtained:

[0094] (4)

[0095] The above formula includes frequency deviation and frequency acceleration To estimate the frequency acceleration, based on equation (2), each adjacent two terms in the first value are and Multiply the difference conjugate again to get the third value (given by 2 differential conjugate multiplication results), the influence of frequency deviation on the solution can be eliminated, that is:

[0096]

[0097] in, For noise.

[0098] To obtain The two results (third values) are averaged to eliminate the influence of noise, and we can get:

[0099]

[0100] in, is the noise average.

[0101] Considering ,therefore

[0102]

[0103] The above formula is simplified to:

[0104]

[0105] in, It is still a Gaussian distribution. Ignoring the influence of noise, the above formula is used to calculate the principal value of the argument (the second principal value of the argument) to obtain :

[0106] (5)

[0107] So the frequency acceleration can be obtained Estimated value of :

[0108]

[0109] On this basis, by combining equation (4) and equation (5), we can get the frequency deviation: Estimated value of for:

[0110]

[0111] In the above embodiment, since the synchronization sequence is segmented and multiplexed in the burst signal, a group of equations including frequency deviation and phase (principal value of the argument) is obtained by calculating the angle of the correlation value (differential conjugate multiplication) between the received signal and the local signal (local unique word sequence), and finally the estimated value of the frequency deviation and the estimated value of the frequency acceleration are obtained by solving the group of equations.

[0112] The above-mentioned embodiments can enable ground satellite Internet equipment to adapt to a larger Doppler frequency deviation, and can well complete the detection and frequency deviation estimation of burst signals at a lower signal-to-noise ratio.

[0113] join Figure 6 , the embodiment of the present application also provides a burst signal processing system, which includes:

[0114] A shift module, used for shifting the received burst signal to obtain multiple groups of shifted signals; the burst signal includes a unique word;

[0115] A first calculation module, used for obtaining a plurality of groups of first signals according to a plurality of groups of shift signals and a local unique word sequence;

[0116] A second calculation module, used for obtaining a first value according to the adjacent data in the plurality of groups of first signals;

[0117] The burst signal processing module is used to process the burst signal according to the first value.

[0118] See also Figure 7, an embodiment of the present application further provides an electronic device, which includes a memory and a processor, the memory stores a computer program, and when the computer program is executed by the processor, the burst signal processing method described in the above embodiment is implemented. As an example, the electronic device may include multiple processors. The processor may refer to one or more devices, circuits, and / or computing units for processing data (such as computer programs). The processor may call the computer program stored in the memory to implement the burst signal processing method described in the above embodiment. Figure 7 In the example, an electronic device including 1 processor and 1 memory is taken as an example. The processor and the memory are respectively used to indicate a type of device or equipment. The quantity of each type of device or equipment can be determined according to business requirements.

[0119] The embodiment of the present application further provides a computer-readable storage medium, which includes a computer program or instructions. When the computer program or instructions are executed on a computer, the computer executes the burst signal processing method described in the above embodiment.

[0120] It should be noted that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0121] Those skilled in the art should clearly understand that, for the convenience and brevity of description, the specific working processes of the burst signal processing system, electronic device and computer-readable storage medium described in the above embodiments can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0122] A person of ordinary skill in the art will appreciate that all or part of the steps to implement the above embodiments may be accomplished by hardware, or may be accomplished by instructing the relevant hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk, or an optical disk, etc.

[0123] The above are only optional embodiments of the present application, which are only used to illustrate the technical solution of the present application rather than to limit it. Without departing from the spirit and scope of the present application, modifications, equivalent substitutions, improvements, etc. to the specific implementation methods of the present application should all be included in the protection scope of the present application.

Claims

1. A method for processing a burst signal, characterized in that: include: Shifting the received burst signal to obtain multiple groups of shifted signals; the burst signal includes a unique word; According to the plurality of groups of shift signals and the local unique word sequence, a plurality of groups of first signals are obtained, comprising: correspondingly multiplying each group of the shift signals in the plurality of groups of shift signals with each local unique word in the local unique word sequence to obtain the plurality of groups of first signals; each group of the shift signals corresponds to each local unique word one by one; Obtaining a first value according to adjacent data in the plurality of groups of first signals, comprising: performing differential conjugate multiplication on adjacent bits in the plurality of groups of first signals in sequence to obtain the first value; The burst signal is processed according to the first value, including: judging whether the burst signal is detected according to the first value and a preset threshold; if the burst signal is detected, obtaining a frequency offset estimation result of the burst signal.

2. The method for processing burst signals according to claim 1, characterized in that: The received burst signal is shifted to obtain multiple groups of shifted signals, including: Sampling the received burst signal to obtain a sampled signal; The sampling signal is shifted to obtain multiple groups of shifted signals.

3. The method for processing burst signals according to claim 1, characterized in that: The determining, according to the first value and a preset threshold, whether the burst signal is detected includes: Calculate the average value of the first value, and extract the envelope square of the average value; Dividing the envelope square by the signal power of the burst signal to obtain a second value; The second value is compared with a preset threshold to determine whether the burst signal is detected.

4. The method for processing burst signals according to claim 3, characterized in that: The comparing the second value with a preset threshold to determine whether the burst signal is detected includes: If the second value is greater than a preset threshold, it indicates that the burst signal has been detected.

5. The method for processing burst signals according to claim 1, characterized in that: The obtaining of a frequency offset estimation result of the burst signal includes: Calculate an average value of the first values, and calculate a first argument principal value of the average value; Obtaining a third value according to adjacent bits in the first value; A frequency offset estimation result is obtained according to the first argument principal value and the third value; the frequency offset estimation result includes an estimated value of frequency acceleration and an estimated value of frequency offset.

6. The method for processing burst signals according to claim 5, characterized in that: The obtaining a third value according to adjacent bits in the first value includes: Adjacent bits in the first value are sequentially differentially conjugate multiplied to obtain a third value.

7. The method for processing a burst signal according to claim 5 or 6, characterized in that: The obtaining a frequency offset estimation result according to the first argument principal value and the third value includes: Calculating an average value of the third values; Obtaining a second argument principal value of the average value of the third value; Obtaining an estimated value of the frequency acceleration according to the second argument principal value; An estimated value of the frequency offset is obtained according to the first argument principal value and the second argument principal value.

8. A burst signal processing system, characterized in that: include: A shift module, used for shifting the received burst signal to obtain multiple groups of shifted signals; the burst signal includes a unique word; A first calculation module, configured to obtain a plurality of groups of first signals according to the plurality of groups of shift signals and the local unique word sequence, comprising: correspondingly multiplying each group of the shift signals in the plurality of groups of shift signals with each local unique word in the local unique word sequence to obtain the plurality of groups of first signals; each group of the shift signals corresponds to each local unique word one by one; A second calculation module, configured to obtain a first value according to adjacent data in the plurality of groups of first signals, comprising: performing differential conjugate multiplication on adjacent bits in the plurality of groups of first signals in sequence to obtain the first value; The burst signal processing module is used to process the burst signal according to the first value, including: judging whether the burst signal is detected according to the first value and a preset threshold; if the burst signal is detected, obtaining a frequency deviation estimation result of the burst signal.

9. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the burst signal processing method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a computer program or an instruction. When the computer program or the instruction is executed on a computer, the computer is enabled to execute the burst signal processing method according to any one of claims 1 to 7.

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