A method and system for adaptive capture of chirp signals

Abstract

The application provides a method and system for adaptively capturing a Chirp signal, wherein the method comprises: performing amplitude adjustment on received digital baseband data based on output gear information of a DAGC to obtain modified data; calculating an arbitrary correction factor according to preset configuration parameters and the output gear information; generating a local Chirp signal same as a Chirp signal of a sending end, and generating two extended signals based on the local Chirp signal; determining original peak values of the two extended signals respectively according to the modified data and the two extended signals; determining corrected peak values of the two extended signals according to the correction factor, preset configuration parameters and the original peak values; determining a corrected average value of correlation energy of the two extended signals according to the corrected peak values; and determining a signal detection result according to the corrected peak values and the corrected average value, and a preset signal detection criterion. The method and system improve the capture performance and reduce the false alarm rate.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and more specifically, to a method and system for adaptively capturing Chirp signals. Background Technology

[0002] With the rapid development of wireless communication and network technologies, the speed and breadth of information dissemination have seen a qualitative leap. Simultaneously, people have placed higher demands on the effectiveness, reliability, flexibility, communication range, and power consumption of communication devices. In the field of wireless spread spectrum, Chirp spread spectrum technology has been widely used due to its excellent pulse compression characteristics, low complexity, low power consumption, good resistance to multipath interference, and suitability for long-distance transmission. As early as 2004, it was even listed as one of the backup physical layer technologies in the IEEE 802.15.4 standard.

[0003] However, with the expansion of Chirp technology's application areas and scenarios, higher demands are being placed on the performance and power consumption of wireless communication devices in bursty communications. Energy detection for wireless signal acquisition, as the first step in wireless communication, is a crucial factor affecting communication performance and power consumption. Therefore, in various wireless environments, improving signal acquisition performance, reducing false alarm rates, and ensuring high acquisition performance have become essential issues that must be addressed for further application.

[0004] Synchronization in spread spectrum systems comprises two parts: acquisition and tracking. Acquisition, being the key component, has always been a hot research topic. The principle of synchronous acquisition for spreading codes involves calculating and comparing the correlation values ​​of the spreading code across 2N phase states. The acquisition state is determined by a threshold decision. However, if the acquisition threshold is set too low, while the acquisition rate can be guaranteed, the false alarm rate will increase, and the system reliability will decrease. Conversely, if the threshold is set too high, although the system reliability improves, the acquisition probability decreases, and the system sensitivity decreases. Therefore, typical acquisition schemes currently employ accumulation algorithms: coherent accumulation, incoherent accumulation, and differential coherent accumulation, to improve the signal-to-noise ratio of the signal input to the decision module, thereby increasing the sensitivity of the decision module.

[0005] While existing solutions improve the signal-to-noise ratio by accumulating signals to enhance acquisition threshold-based decision-making, they suffer from the following drawbacks:

[0006] Threshold-based acquisition schemes often employ a fixed, single-dimensional acquisition threshold. However, in the presence of strong out-of-band interference, the amplification factor of the analog automatic gain control (AAGC) is referenced to the interference signal. This means the effective signal cannot achieve the desired amplification factor, resulting in a reduced amplitude and lower peak energy of the quantized data signal, thus degrading the receiver's acquisition performance. Therefore, digital automatic gain control (DAGC) is needed as a supplement to AAGC. DAGC effectively addresses the problem of suboptimal amplification of the useful signal energy caused by strong out-of-band interference in the received signal. Furthermore, considering the diversity of environmental interference, the accuracy of DAGC settings, and the differences in hardware such as receiving antennas in practical applications, fine-tuning of the signal power based on DAGC settings is necessary to ensure optimal acquisition performance. Summary of the Invention

[0007] To address the issue of low performance in existing threshold-based capture schemes that employ fixed and single-dimensional capture thresholds, this invention provides a method and system for adaptively capturing Chirp signals.

[0008] According to one aspect of the present invention, an adaptive method for capturing Chirp signals is provided, the method comprising:

[0009] Based on the output range information of DAGC, the amplitude of the received digital baseband data is adjusted to obtain the corrected data;

[0010] Calculate an arbitrary correction factor based on preset configuration parameters and the output gear information, wherein the configuration parameters include the DAGC gear adjustment threshold, the energy adjustment coefficient of the denominator, the common value of the coefficient numerator, and the gear step.

[0011] Generate a local Chirp signal identical to the Chirp signal from the transmitting end, and generate two extended signals based on the local Chirp signal;

[0012] The circular autocorrelation processing of the corrected data and the two extended signals is performed based on the Fast Fourier Transform (FFT) algorithm to determine the original peak values ​​of the two extended signals.

[0013] The original peak values ​​of the two extended signals are corrected according to the correction factor and the preset configuration parameters to obtain their respective corrected peak values;

[0014] The corrected average value of the relevant energy of each of the two extended signals is determined based on the corrected peak value after removing the m energies centered on the corrected peak value.

[0015] The signal detection result is determined based on the corrected peak value and corrected average value, as well as the pre-set signal detection criteria.

[0016] Optionally, the step of calculating an arbitrary correction factor based on preset configuration parameters and the output gear information includes:

[0017] When the output gear information is less than or equal to the gear adjustment threshold, a correction factor is calculated. The formula for calculating the correction factor is:

[0018] Factor = (1 < <ChgDenBit)- PwrChgCom+(PwrChgCom-DagcThr)*Step

[0019] In the formula, Factor is the correction factor, ChgDenBit is the energy adjustment coefficient in the denominator, PwrChgCom is the common value of the coefficient numerator, Step is the gear step, and << is the operator for left shift.

[0020] Optionally, generating a local Chirp signal identical to the Chirp signal at the transmitting end, and generating two extended signals based on the local Chirp signal, includes:

[0021] A local chirp signal is generated using a local chirp signal generator;

[0022] The local Chrip signal is sampled to obtain sampled data, wherein the sampled data includes N chips;

[0023] The sampled data is divided into equal parts at the beginning and end, and two extended signals are generated by zero-padding at the end and beginning. Each extended signal is a sequence of length N, and its expression is:

[0024]

[0025] In the formula, PreamChrip is the sampled data, and PChrip and QChrip are two extended signals.

[0026] Optionally, the original peak values ​​of the two extended signals are corrected according to the correction factor and preset configuration parameters to obtain their respective corrected peak values, wherein the formula for determining the corrected peak value is:

[0027] PtvMax = (PvMax*Factor)>>ChgDenBit;

[0028] QtvMax = (QvMax*Factor)>>ChgDenBit

[0029] In the formula, Factor is the correction factor, ChgDenBit is the energy adjustment coefficient in the denominator, PvMax and QvMax represent the original peak values ​​of the two extended signals, PtvMax and QtvMax represent the corrected peak values ​​of the two extended signals, and >> is the right shift operator.

[0030] Optionally, determining the signal detection result based on the corrected peak value and the corrected average value, and a pre-set signal detection criterion, includes:

[0031] Calculate the corrected peak-to-average power ratio (PAPR) of each of the two extended signals based on the corrected peak value and the corrected average value.

[0032] The signal detection result is determined based on the corrected peak value and the corrected peak-to-average power ratio, as well as a pre-set signal detection criterion, wherein the expression for the signal detection criterion is:

[0033] PtvMax>PwrThr

[0034] QtvMax>PwrThr

[0035] PtvAvg>CADRatio

[0036] QtvAvg>CADRatio

[0037] In the formula, PtvAvg and QtvAvg represent the corrected peak-to-average power ratios of the two extended signals, respectively;

[0038] When all of the signal detection criterion expressions are true, the signal detection result is determined to be successful; when at least one of the signal detection criterion expressions is false, the signal detection result is determined to be unsuccessful.

[0039] According to another aspect of the present invention, the present invention provides a system for adaptively capturing Chirp signals, the system comprising:

[0040] The data correction module is used to adjust the amplitude of the received digital baseband data based on the output range information of DAGC to obtain corrected data;

[0041] The correction factor module is used to calculate any correction factor based on preset configuration parameters and the output gear information. The configuration parameters include the DAGC gear adjustment threshold, the energy adjustment coefficient of the denominator, the common value of the coefficient numerator, and the gear step.

[0042] An extended signal module is used to generate a local Chirp signal that is identical to the Chirp signal at the transmitting end, and to generate two extended signals based on the local Chirp signal;

[0043] The signal despreading module is used to perform circumferential autocorrelation processing between the corrected data and the two extended signals based on the Fast Fourier Transform (FFT) algorithm, and to determine the original peak values ​​of the two extended signals respectively.

[0044] The peak correction module is used to correct the original peak values ​​of the two extended signals according to the correction factor and the preset configuration parameters to obtain their respective corrected peak values.

[0045] The energy averaging module is used to determine the corrected average value of the relevant energy of the two extended signals after removing the m energies centered on the corrected peak value.

[0046] The signal detection module is used to determine the signal detection result based on the corrected peak value and the corrected average value, as well as the preset signal detection criteria.

[0047] Optionally, the correction factor module calculates an arbitrary correction factor based on preset configuration parameters and the output gear information, including:

[0048] When the output gear information is less than or equal to the gear adjustment threshold, a correction factor is calculated. The formula for calculating the correction factor is:

[0049] Factor = (1 < <ChgDenBit)- PwrChgCom+(PwrChgCom-DagcThr)*Step

[0050] In the formula, Factor is the correction factor, ChgDenBit is the energy adjustment coefficient in the denominator, PwrChgCom is the common value of the coefficient numerator, Step is the gear step, and << is the operator for left shift.

[0051] Optionally, the extended signal module generates a local Chirp signal identical to the Chirp signal at the transmitting end, and generates two extended signals based on the local Chirp signal, including:

[0052] A local chirp signal is generated using a local chirp signal generator;

[0053] The local Chrip signal is sampled to obtain sampled data, wherein the sampled data includes N chips;

[0054] The sampled data is divided into equal parts at the beginning and end, and two extended signals are generated by zero-padding at the end and beginning. Each extended signal is a sequence of length N, and its expression is:

[0055]

[0056] In the formula, PreamChrip is the sampled data, and PChrip and QChrip are two extended signals.

[0057] Optionally, the peak correction module corrects the original peak values ​​of the two extended signals according to the correction factor and preset configuration parameters to obtain their respective corrected peak values, wherein the formula for determining the corrected peak value is:

[0058] PtvMax = (PvMax*Factor)>>ChgDenBit;

[0059] QtvMax = (QvMax*Factor)>>ChgDenBit

[0060] In the formula, Factor is the correction factor, ChgDenBit is the energy adjustment coefficient in the denominator, PvMax and QvMax represent the original peak values ​​of the two extended signals, PtvMax and QtvMax represent the corrected peak values ​​of the two extended signals, and >> is the right shift operator.

[0061] Optionally, the signal detection module determines the signal detection result based on the corrected peak value and the corrected average value, as well as a pre-set signal detection criterion, including:

[0062] Calculate the corrected peak-to-average power ratio (PAPR) of each of the two extended signals based on the corrected peak value and the corrected average value.

[0063] The signal detection result is determined based on the corrected peak value and the corrected peak-to-average power ratio, as well as a pre-set signal detection criterion, wherein the expression for the signal detection criterion is:

[0064] PtvMax>PwrThr

[0065] QtvMax>PwrThr

[0066] PtvAvg>CADRatio

[0067] QtvAvg>CADRatio

[0068] In the formula, PtvAvg and QtvAvg represent the corrected peak-to-average power ratios of the two extended signals, respectively;

[0069] When all of the signal detection criterion expressions are true, the signal detection result is determined to be successful; when at least one of the signal detection criterion expressions is false, the signal detection result is determined to be unsuccessful.

[0070] The present invention provides a method and system for adaptively capturing chirp signals. The method includes: adjusting the amplitude of received digital baseband data based on the output level information of a digital baseband controller (DAGC) to obtain corrected data; calculating an arbitrary correction factor according to preset configuration parameters and the output level information; generating a local chirp signal identical to the chirp signal from the transmitting end, and generating two extended signals based on the local chirp signal; performing circular autocorrelation processing on the corrected data and the two extended signals using a Fast Fourier Transform (FFT) algorithm to determine the original peak values ​​of each of the two extended signals; correcting the original peak values ​​of each of the two extended signals according to the correction factor and the preset configuration parameters to obtain their respective corrected peak values; determining the corrected average value of the correlation energy of each of the two extended signals after removing m energies centered at the corrected peak value; and determining the signal detection result based on the corrected peak value, the corrected average value, and a preset signal detection criterion. This method provides a simple and rapid adjustment scheme for correction factors under arbitrary precision, solves the problem of interference signals affecting the energy assessment fluctuations of AAGC and DAGC in practical application environments, and reduces the performance requirements of the analog front end during signal detection to a certain extent. By constructing two strongly correlated local extended chirp signals and combining them with a multi-dimensional acquisition decision mechanism, the problem of high false alarm rate caused by single decision is solved, further improving the acquisition performance. Moreover, by reducing the false alarm rate and reducing invalid communication, low power consumption is ensured during signal detection. Attached Figure Description

[0071] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0072] Figure 1 A flowchart of a method for adaptively capturing Chirp signals according to a preferred embodiment of the present invention;

[0073] Figure 2a This is a time-frequency diagram of the preamble chirp signal according to a preferred embodiment of the present invention;

[0074] Figure 2b This is a time-frequency diagram of the PCHirp signal according to a preferred embodiment of the present invention;

[0075] Figure 2c This is a time-frequency diagram of the QChirp signal according to a preferred embodiment of the present invention;

[0076] Figure 3a This is a schematic diagram of the circumferential correlation energy between the noise-free but timing-biased corrected data and the PCHirp signal according to a preferred embodiment of the present invention.

[0077] Figure 3bThis is a schematic diagram of the circumferential correlation energy between the noise-free but timing-biased corrected data and the QChirp signal according to a preferred embodiment of the present invention.

[0078] Figure 4a The waveform of PreamChirp data received in the I-channel when the timing deviation is 0, according to a preferred embodiment of the present invention;

[0079] Figure 4b The above is a time-domain waveform of the PreamChirp data received in the I-channel when the timing deviation is 0.4ms according to a preferred embodiment of the present invention.

[0080] Figure 5a The image shows the time-domain waveform of the PreamChirp data received when the timing deviation is 0, according to a preferred embodiment of the present invention, in the Q-channel.

[0081] Figure 5b The above is a time-domain waveform of the PreamChirp data received in the Q channel when the timing deviation is 0.4 ms, according to a preferred embodiment of the present invention.

[0082] Figure 6a The waveform of PreamChirp data received in the I-channel when the timing deviation is 0.4ms according to a preferred embodiment of the present invention;

[0083] Figure 6b The time-domain waveform of Pchirp data in the I channel when the timing deviation is 0 according to a preferred embodiment of the present invention;

[0084] Figure 6c The time-domain waveform of Qchirp data in the I channel when the timing deviation is 0 according to a preferred embodiment of the present invention;

[0085] Figure 7 This is a schematic diagram of the structure of a system for adaptively capturing Chirp signals according to a preferred embodiment of the present invention. Detailed Implementation

[0086] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0087] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0088] Exemplary methods

[0089] Figure 1 This is a flowchart of a method for adaptively capturing Chirp signals according to a preferred embodiment of the present invention. Figure 1 As shown, the method described in this preferred embodiment begins with step 101.

[0090] In step 101, based on the output level information of DAGC, the amplitude of the received digital baseband data is adjusted to obtain corrected data.

[0091] In step 102, an arbitrary correction factor is calculated based on preset configuration parameters and the output gear information. The configuration parameters include the DAGC gear adjustment threshold, the energy adjustment coefficient of the denominator, the common value of the coefficient numerator, and the gear step.

[0092] Preferably, the step of calculating the arbitrary correction factor based on the preset configuration parameters and the output gear information includes:

[0093] When the output gear information is less than or equal to the gear adjustment threshold, a correction factor is calculated. The formula for calculating the correction factor is:

[0094] Factor = (1 < <ChgDenBit)- PwrChgCom+(PwrChgCom-DagcThr)*Step

[0095] In the formula, Factor is the correction factor, ChgDenBit is the energy adjustment coefficient in the denominator, PwrChgCom is the common value of the coefficient numerator, Step is the gear step, and << is the operator for left shift.

[0096] The calculation formula for the correction factor Factor described in this preferred embodiment fully considers both the flexibility of the adjustment factor and the accuracy of fixed-pointing in specific implementations. Tables 1a and 1b divide the DAGC output levels into 0 to 9 levels and provide specific comparisons. Table 1a shows the adjustment ratio of the absolute peak threshold for each level under four configurations of parameters [DagcThr, PwrChgCom, ChgDenBit, Step]: PeakThrCoef = Factor / (2^ChgDenBit). Table 1b shows the peak-to-average power ratio (PAPR) threshold adjustment ratio corresponding to Table 1a: RatioThrCoef = 1 / PeakThrCoef, where the PAPR is the ratio of the peak value to the average energy value determined by analyzing the Chirp signal.

[0097]

[0098] As can be seen from Table 1a, the PeakThrCoef correlation peak-to-peak adjustment factor based on DAGC gear information used in this invention can meet the following factor correction requirements in practical applications:

[0099] (1) Parameter DagcThr controls the range of DAGC gears applicable to the peak adjustment scheme;

[0100] (2) The combined settings of parameters DagcThr, PwrChgCom, and ChgDenBit fulfill the requirement of the adjustment factor size gap between DagcThr and DagcThr+1.

[0101] (3) The Step and ChgDenBit parameters are set together to meet the adjustment requirements of different advance precision PrecStep between DAGC gears;

[0102] (4) The combined settings of parameters DagcThr, PwrChgCom, ChgDenBit, and Step realize the overall requirements of Gap size, adjustment factor step precision PrecStep, and adjustment factor span [Scope-Max, Scope-Min] based on AGC gear adjustment in the actual application environment.

[0103] Table 2 presents the requirements analysis results based on the configurations in Tables 1a and 1b.

[0104] Table 2

[0105] Idx Gap PrecStep Scope-Max Scope-Min 1 0.188 0.031 0.813 0.594 2 0.047 0.008 0.953 0.898 3 0.047 0.063 0.953 0.516 4 0.020 0.003 0.980 0.960

[0106] As is well known, DAGC, as a supplement to AAGC, effectively addresses the problem of suboptimal amplification of the useful signal energy caused by strong out-of-band interference in the received signal. The DAGC level is directly proportional to the degree of suboptimal amplification of the AAGC; that is, the larger the DAGC level, the greater the amplification required after low-pass filtering, and the greater the difference between the AAGC amplification and the ideal amplification. Theoretically, the two-stage power assessment and scaling of AAGC and DAGC ensure relatively stable power for the despread input received signal. However, in actual wireless channel environments, considering the diversity of noise, the accuracy of DAGC levels, and the differences in hardware such as receiving antennas, it is necessary to fine-tune the signal power based on the DAGC level information to ensure acquisition performance. In this invention, the correction factor is calculated based on the DAGC output level information and the preset configuration parameters. This allows for simple and rapid adjustment of any correction factor under any precision, thereby enabling the assessment of energy fluctuations of AAGC and DAGC in application environments with actual interference signals. By influencing the correlation peak value and peak-to-average power ratio of the signal, the power of the signal is adjusted, ensuring high performance in signal acquisition.

[0107] In step 103, a local Chirp signal identical to the Chirp signal at the transmitting end is generated, and two extended signals are generated based on the local Chirp signal.

[0108] Preferably, the generation of a local Chirp signal identical to the Chirp signal at the transmitting end, and the generation of two extended signals based on the local Chirp signal, includes:

[0109] A local chirp signal is generated using a local chirp signal generator;

[0110] The local Chrip signal is sampled to obtain sampled data, wherein the sampled data includes N chips;

[0111] The sampled data is divided into equal parts at the beginning and end, and two extended signals are generated by zero-padding at the end and beginning. Each extended signal is a sequence of length N, and its expression is:

[0112]

[0113] In the formula, PreamChrip is the sampled data, and PChrip and QChrip are two extended signals.

[0114] In this preferred embodiment, the basic parameters for the chirp signal generated by the transmitting end are configured as follows: bandwidth BW = 125kHz, spreading factor SF = 8, symbol period Tc = 2.048ms, sampling rate fs = 250kHz, and spreading signal slope. Then the leading Chirp signal is:

[0115] In a preferred embodiment, a local chirp signal is generated in a local chirp signal generator. c(t) The expression is as follows:

[0116]

[0117] In the above formula, The initial phase is arbitrary; in this embodiment, it is set to 0. After the local Chirp generator at the receiving end generates the local Chirp signal, it is sampled to obtain the PreamChirp signal. By performing equal-ratio splitting and zero-padding on the PreamChirp signal, two spreading sequences with the same symbol period Tc and strong correlation to the PreamChirp signal can be generated; these are the spread signals PChrip and QChrip.

[0118] Figures 2a to 2c Time-frequency diagrams of the preamble chirp signal, PChrip, and QChrip are given respectively.

[0119] Figure 2a This is a time-frequency diagram of the preamble chirp signal according to a preferred embodiment of the present invention. Figure 2a As shown, the preamble chirp signal is a signal with a symbol period of Tc generated according to the set parameters.

[0120] Figure 2b This is a time-frequency diagram of the PCHirp signal according to a preferred embodiment of the present invention. Figure 2b As shown, when the preamble chirp signal is divided into equal parts, the resulting PChirp signal consists of chips in the first Tc / 2 period and zero-padding in the second Tc / 2 period.

[0121] Figure 2c This is a time-frequency diagram of the QChirp signal according to a preferred embodiment of the present invention. Figure 2c As shown, unlike the PChirp signal, the QChirp signal is obtained by dividing the leading Chirp signal into equal parts, with the last Tc / 2 period being the chip and the first Tc / 2 period being padded with zeros.

[0122] By dividing the local Chirp signal into equal parts before and after, two extended signals with strong correlation to the received Chirp signal are generated, namely the pseudocode sequences PChirp and QChirp. This ensures that during the despreading correlation processing, both the beginning and end parts of the corrected data obtained after correcting the received data have strong correlation with the PreamChirp signal, avoiding false alarm probability caused by partial correlation and improving detection accuracy.

[0123] In step 104, the circular autocorrelation processing of the corrected data and the two extended signals is performed based on the Fast Fourier Transform (FFT) algorithm to determine the original peak values ​​of the two extended signals.

[0124] Figure 3a This is a schematic diagram of the circumferential correlation energy between the noise-free corrected data with a timing deviation of 0.4ms according to a preferred embodiment of the present invention and the PCHirp signal. Figure 3b This is a schematic diagram of the circumferential correlation energy between the noise-free corrected data (with a timing deviation of 0.4 ms) and the QChirp signal according to a preferred embodiment of the present invention. Figure 3a and Figure 3b As shown, when the corrected data obtained by amplitude modulation of the digital baseband data received under noise-free conditions but with a timing deviation of 0.4ms is compared with the local correlation energy peak of the PChirp and QChirp signals based on FFT to realize circular convolution, there is a significant spike, indicating that the two have good correlation characteristics.

[0125] After the PreamChrip signal is divided into equal parts, it is extended to a length of N by zero padding to generate two extended signals PChirp and QChirp. This ensures that the energy detection of the corrected data and PChirp and QChirp is realized quickly based on FFT circular convolution, and is not affected by timing deviation.

[0126] Figure 4a and Figure 5a The time-domain waveforms of the I and Q channels of PreamChirp are compared when the timing deviation Tshift = 0. Figure 4b and Figure 5b The time-domain waveforms of the I and Q channels of PreamChirp are compared when the timing deviation Tshift = 0.4ms. Figure 4a and Figure 4b It was found that, under timing deviation, Figure 4b Equivalent to Figure 4a The spread spectrum sequence is circularly shifted, with the dashed box portion moved to the end of the sequence. Similarly, compare... Figure 5a and Figure 5b It was found that, under timing deviation, Figure 5b Equivalent to Figure 5a The spread spectrum sequence is circularly shifted, and the dashed box portion is moved to the end of the sequence.

[0127] Figure 6a The waveform of PreamChirp data received at a timing deviation of 0.4ms according to a preferred embodiment of the present invention is shown in the time domain of the I-channel. Figure 6b This is the time-domain waveform of Pchirp data in the I-channel when the timing deviation is 0, according to a preferred embodiment of the present invention. Figure 6c To illustrate the time-domain waveform of Qchirp data in the I-channel when the timing deviation is 0 according to a preferred embodiment of the present invention, combined with... Figure 6a , 6b Comparative analysis of PCHirp and QChirp shows that the received preamble spreading sequence PreamChrip, which has a timing deviation of 0.4ms, requires a certain length of circular cyclic shift to achieve symbol alignment and good correlation peaks. Therefore, zero-padding and extending PCHirp and QChirp to N is particularly important. Without zero-padding, the original PCHirp and QChirp lengths are N / 2, and the system can only perform local correlation processing of length N / 2, requiring a sliding correlation scheme. Because... Figure 6a , Figure 6b As shown in the large dashed box, the circular correlation based on FFT cannot achieve optimal correlation performance. In extreme cases, it can even cause a sharp drop in the correlation peak, resulting in missed detections.

[0128] In this embodiment, PCHirp and QChirp are extended to the code length N of the local Chirp signal by zero padding at the front and back ends. After generating two extended signals PCHirp and QChirp, the circumferential correlation peak between the corrected data and the local pseudocodes PCHirp and QChirp implemented by FFT is not affected by the timing deviation. Moreover, the zero padding instead of pseudo-random code extension effectively reduces the computational complexity and avoids increasing the noise floor of the correlation results.

[0129] In step 105, the original peak values ​​of the two extended signals are corrected according to the correction factor and the preset configuration parameters to obtain their respective corrected peak values.

[0130] Preferably, the original peak values ​​of the two extended signals are corrected according to the correction factor and preset configuration parameters to obtain their respective corrected peak values, wherein the formula for determining the corrected peak value is:

[0131] PtvMax = (PvMax*Factor)>>ChgDenBit;

[0132] QtvMax = (QvMax*Factor)>>ChgDenBit

[0133] In the formula, Factor is the correction factor, ChgDenBit is the energy adjustment coefficient in the denominator, PvMax and QvMax represent the original peak values ​​of the two extended signals, PtvMax and QtvMax represent the corrected peak values ​​of the two extended signals, and >> is the right shift operator.

[0134] In this preferred embodiment, considering the impact of energy fluctuations in AAGC and DAGC on signal detection under various interferences in the application environment, the peak values ​​of PChirp and QChirp are first corrected based on the correction factor Factor of the DAGC level. This enables the absolute peak threshold PwrThr and peak-to-average ratio threshold CADRatio in signal detection to automatically adapt to various DAGC levels, ensuring a reduced false detection rate.

[0135] In step 106, the corrected average value of the correlation energy of each of the two extended signals after removing the m energies centered at the corrected peak value is determined based on the corrected peak value. In this preferred embodiment, m is set comprehensively based on the correlation between PChirp and QChirp, as well as the data acquisition rate.

[0136] In step 107, the signal detection result is determined based on the corrected peak value and the corrected average value, as well as the preset signal detection criteria.

[0137] Preferably, determining the signal detection result based on the corrected peak value and the corrected average value, as well as a pre-set signal detection criterion, includes:

[0138] Calculate the corrected peak-to-average power ratio (PAPR) of each of the two extended signals based on the corrected peak value and the corrected average value.

[0139] The signal detection result is determined based on the corrected peak value and the corrected peak-to-average power ratio, as well as a pre-set signal detection criterion, wherein the expression for the signal detection criterion is:

[0140] PtvMax>PwrThr

[0141] QtvMax>PwrThr

[0142] PtvAvg>CADRatio

[0143] QtvAvg>CADRatio

[0144] In the formula, PtvAvg and QtvAvg represent the corrected peak-to-average power ratios of the two extended signals, respectively;

[0145] When all of the signal detection criterion expressions are true, the signal detection result is determined to be successful; when at least one of the signal detection criterion expressions is false, the signal detection result is determined to be unsuccessful.

[0146] In the signal detection described above, the first two are absolute threshold criteria, and the latter two are relative threshold criteria. These four criterion expressions achieve joint judgment from both absolute and relative dimensions, effectively avoiding false detections caused by only satisfying the judgment condition in a single dimension. Simultaneously, by employing two strongly correlated local pseudocodes, PChirp and Qchirp, and using the corrected peak value and corrected peak-to-average power ratio calculated from them, a comprehensive judgment of the joint correlation between the preceding and following parts within a symbol period is achieved. This reduces false detections caused by local strong correlations to some extent, further improving acquisition performance.

[0147] In summary, in this preferred embodiment, firstly, the correction factor is calculated based on the DAGC gear information and the configured parameters, thereby adaptively adjusting the signal detection threshold and improving acquisition performance; secondly, based on the local Chirp signal generated by the local Chirp signal generator, two extended signals with strong correlation to the transmitting Chirp signal are obtained, thus ensuring that the correction data obtained based on the received digital baseband data has a strong correlation with the transmitting Chirp signal throughout the entire symbol period, and ensuring that sliding local cross-correlation can be achieved using FFT circular convolution, simplifying the computational complexity of correlation and unaffected by timing deviations; thirdly, the signal detection criterion effectively avoids false detection caused by only satisfying the decision condition in a single dimension by simultaneously setting absolute and relative threshold criteria, ensuring a low false alarm rate.

[0148] Exemplary System

[0149] Figure 7 This is a schematic diagram of the structure of a system for adaptively capturing Chirp signals according to a preferred embodiment of the present invention. Figure 7 As shown, the system 700 of this preferred embodiment includes:

[0150] Data correction module 701 is used to adjust the amplitude of the received digital baseband data based on the output range information of DAGC to obtain corrected data;

[0151] The correction factor module 702 is used to calculate an arbitrary correction factor based on preset configuration parameters and the output gear information, wherein the configuration parameters include the gear adjustment threshold of DAGC, the energy adjustment coefficient of the denominator, the common value of the coefficient numerator, and the gear step.

[0152] The extended signal module 703 is used to generate a local Chirp signal that is the same as the Chirp signal at the transmitting end, and to generate two extended signals based on the local Chirp signal;

[0153] The signal despreading module 704 is used to perform circumferential autocorrelation processing between the corrected data and the two extended signals based on the Fast Fourier Transform (FFT) algorithm, and to determine the original peak values ​​of the two extended signals respectively.

[0154] The peak correction module 705 is used to correct the original peak values ​​of the two extended signals according to the correction factor and the preset configuration parameters to obtain their respective corrected peak values.

[0155] The energy averaging module 706 is used to determine the corrected average value of the relevant energy of the two extended signals after removing the left and right m energies centered on the corrected peak value, based on the corrected peak value.

[0156] The signal detection module 707 is used to determine the signal detection result based on the corrected peak value and the corrected average value, as well as the preset signal detection criteria.

[0157] Preferably, the correction factor module 702 calculates an arbitrary correction factor based on preset configuration parameters and the output gear information, including:

[0158] When the output gear information is less than or equal to the gear adjustment threshold, a correction factor is calculated. The formula for calculating the correction factor is:

[0159] Factor = (1 < <ChgDenBit)- PwrChgCom+(PwrChgCom-DagcThr)*Step

[0160] In the formula, Factor is the correction factor, ChgDenBit is the energy adjustment coefficient in the denominator, PwrChgCom is the common value of the coefficient numerator, Step is the gear step, and << is the operator for left shift.

[0161] Preferably, the extended signal module 703 generates a local Chirp signal identical to the Chirp signal at the transmitting end, and generates two extended signals based on the local Chirp signal, including:

[0162] A local chirp signal is generated using a local chirp signal generator;

[0163] The local Chrip signal is sampled to obtain sampled data, wherein the sampled data includes N chips;

[0164] The sampled data is divided into equal parts at the beginning and end, and two extended signals are generated by zero-padding at the end and beginning. Each extended signal is a sequence of length N, and its expression is:

[0165]

[0166] In the formula, PreamChrip is the sampled data, and PChrip and QChrip are two extended signals.

[0167] Preferably, the peak correction module 705 corrects the original peak values ​​of the two extended signals according to the correction factor and preset configuration parameters to obtain their respective corrected peak values, wherein the formula for determining the corrected peak value is:

[0168] PtvMax = (PvMax*Factor)>>ChgDenBit;

[0169] QtvMax = (QvMax*Factor)>>ChgDenBit

[0170] In the formula, Factor is the correction factor, ChgDenBit is the energy adjustment coefficient in the denominator, PvMax and QvMax represent the original peak values ​​of the two extended signals, PtvMax and QtvMax represent the corrected peak values ​​of the two extended signals, and >> is the right shift operator.

[0171] Preferably, the signal detection module 707 determines the signal detection result based on the corrected peak value and the corrected average value, as well as a pre-set signal detection criterion, including:

[0172] Calculate the corrected peak-to-average power ratio (PAPR) of each of the two extended signals based on the corrected peak value and the corrected average value.

[0173] The signal detection result is determined based on the corrected peak value and the corrected peak-to-average power ratio, as well as a pre-set signal detection criterion, wherein the expression for the signal detection criterion is:

[0174] PtvMax>PwrThr

[0175] QtvMax>PwrThr

[0176] PtvAvg>CADRatio

[0177] QtvAvg>CADRatio

[0178] In the formula, PtvAvg and QtvAvg represent the corrected peak-to-average power ratios of the two extended signals, respectively;

[0179] When all of the signal detection criterion expressions are true, the signal detection result is determined to be successful; when at least one of the signal detection criterion expressions is false, the signal detection result is determined to be unsuccessful.

[0180] The system for adaptively capturing chirp signals described in this preferred embodiment performs amplitude modulation on the received digital baseband data to generate corrected data. It adaptively adjusts the threshold value of the signal detection criterion by acquiring an arbitrary correction factor. It generates two extended signals that are strongly correlated with the chirp signal transmitted from the transmitting end. Based on the Fast Fourier Transform (FFT) algorithm, it performs circumferential autocorrelation processing on the corrected data and the two extended signals to determine the original peak values ​​of each of the two extended signals. After correcting the original peak values ​​to obtain corrected peak values, the step of signal detection using the signal detection criterion is the same as the step of the adaptive chirp signal capture method of this invention, and the achieved technical effects are also the same, so it will not be repeated here.

[0181] The invention has been described with reference to a few embodiments. However, as will be known to those skilled in the art, and as defined in the appended claims, other embodiments besides those disclosed above fall equivalently within the scope of the invention.

[0182] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the art, unless otherwise expressly defined herein. All references to “a / the / the [device, component, etc.]” ​​are openly interpreted as at least one instance of said device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed unless explicitly stated otherwise.

[0183] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of one or more computer-usable storage media (including, but not limited to, disk storage, etc.) containing computer-usable program code. CD - ROM It takes the form of a computer program product implemented on (such as optical memory, etc.).

[0184] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0185] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0186] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0187] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for adaptively capturing Chirp signals, characterized in that, The method includes: Based on the output range information of DAGC, the amplitude of the received digital baseband data is adjusted to obtain the corrected data; Calculate any correction factor based on preset configuration parameters and the output gear information, including: When the output gear information is less than or equal to the DAGC gear adjustment threshold, a correction factor is calculated. The formula for calculating the correction factor is: Factor = (1 < <ChgDenBit)- PwrChgCom+(PwrChgCom-DagcThr)*Step In the formula, Factor is the correction factor, ChgDenBit is the energy adjustment coefficient in the denominator, PwrChgCom is the common value of the coefficient numerator, DagcThr is the gear adjustment threshold of DAGC, Step is the gear step, and << is the operator that represents left shift. Generate a local Chirp signal identical to the Chirp signal at the transmitting end, and generate two extended signals based on the local Chirp signal, including: The local Chrip signal is sampled to obtain sampled data, wherein the sampled data includes N chips; The sampled data is divided into equal parts at the beginning and end, and two extended signals are generated by zero-padding at the end and the beginning. The extended signals are sequences of length N. The circular autocorrelation processing of the corrected data and the two extended signals is performed based on the Fast Fourier Transform (FFT) algorithm to determine the original peak values ​​of the two extended signals. The original peak values ​​of the two extended signals are corrected according to the correction factor and the preset configuration parameters to obtain their respective corrected peak values; The corrected average value of the relevant energy of each of the two extended signals is determined based on the corrected peak value after removing the m energies centered on the corrected peak value. The signal detection result is determined based on the corrected peak value and corrected average value, as well as a pre-set signal detection criterion, including: Calculate the corrected peak-to-average power ratio (PAPR) of each of the two extended signals based on the corrected peak value and the corrected average value. The signal detection result is determined based on the corrected peak value and the corrected peak-to-average power ratio, as well as the preset signal detection criteria.

2. The method according to claim 1, characterized in that, The local chirp signal is generated to be identical to the chirp signal at the transmitting end, and two extended signals are generated based on the local chirp signal, wherein: A local chirp signal is generated using a local chirp signal generator; The extended signals are all sequences of length N, and their expressions are as follows: In the formula, PreamChrip is the sampled data, and PChrip and QChrip are two extended signals.

3. The method according to claim 1, characterized in that, The original peak values ​​of the two extended signals are corrected according to the correction factor and preset configuration parameters to obtain their respective corrected peak values. The formula for determining the corrected peak value is as follows: PtvMax = (PvMax*Factor)>>ChgDenBit; QtvMax = (QvMax*Factor)>>ChgDenBit In the formula, Factor is the correction factor, ChgDenBit is the energy adjustment coefficient in the denominator, PvMax and QvMax represent the original peak values ​​of the two extended signals, PtvMax and QtvMax represent the corrected peak values ​​of the two extended signals, and >> is the right shift operator.

4. The method according to claim 3, characterized in that, The signal detection result is determined based on the corrected peak value and the corrected average value, as well as a pre-set signal detection criterion, wherein the expression for the signal detection criterion is: PtvMax>PwrThr QtvMax>PwrThr PtvAvg>CADRatio QtvAvg>CADRatio In the formula, PtvAvg and QtvAvg represent the corrected peak-to-average ratio of the two extended signals, respectively, and PwrThr and CADRatio represent the absolute peak threshold and peak-to-average ratio threshold, respectively. When all of the signal detection criterion expressions are true, the signal detection result is determined to be successful; when at least one of the signal detection criterion expressions is false, the signal detection result is determined to be unsuccessful.

5. A system for adaptively capturing Chirp signals, characterized in that, The system includes: The data correction module is used to adjust the amplitude of the received digital baseband data based on the output range information of DAGC to obtain corrected data; The correction factor module is used to calculate any correction factor based on preset configuration parameters and the output gear information, including: When the output gear information is less than or equal to the DAGC gear adjustment threshold, a correction factor is calculated. The formula for calculating the correction factor is: Factor = (1 < <ChgDenBit)- PwrChgCom+(PwrChgCom-DagcThr)*Step In the formula, Factor is the correction factor, ChgDenBit is the energy adjustment coefficient in the denominator, PwrChgCom is the common value of the coefficient numerator, DagcThr is the gear adjustment threshold of DAGC, Step is the gear step, and << is the operator that represents left shift. An extended signal module is used to generate a local Chirp signal identical to the Chirp signal at the transmitting end, and to generate two extended signals based on the local Chirp signal, including: The local Chrip signal is sampled to obtain sampled data, wherein the sampled data includes N chips; The sampled data is divided into equal parts at the beginning and end, and two extended signals are generated by zero-padding at the end and the beginning. The extended signals are sequences of length N. The signal despreading module is used to perform circumferential autocorrelation processing between the corrected data and the two extended signals based on the Fast Fourier Transform (FFT) algorithm, and to determine the original peak values ​​of the two extended signals respectively. The peak correction module is used to correct the original peak values ​​of the two extended signals according to the correction factor and the preset configuration parameters to obtain their respective corrected peak values. The energy averaging module is used to determine the corrected average value of the relevant energy of the two extended signals after removing the m energies centered on the corrected peak value. The signal detection module is used to determine the signal detection result based on the corrected peak value and corrected average value, and a pre-set signal detection criterion, including: Calculate the corrected peak-to-average power ratio (PAPR) of each of the two extended signals based on the corrected peak value and the corrected average value. The signal detection result is determined based on the corrected peak value and the corrected peak-to-average power ratio, as well as the preset signal detection criteria.

6. The system according to claim 5, characterized in that, The extended signal module generates a local Chirp signal identical to the Chirp signal at the transmitting end, and generates two extended signals based on the local Chirp signal, wherein: A local chirp signal is generated using a local chirp signal generator; The extended signals are all sequences of length N, and their expressions are as follows: In the formula, PreamChrip is the sampled data, and PChrip and QChrip are two extended signals.

7. The system according to claim 5, characterized in that, The peak correction module corrects the original peak values ​​of the two extended signals according to the correction factor and preset configuration parameters to obtain their respective corrected peak values. The formula for determining the corrected peak value is as follows: PtvMax = (PvMax*Factor)>>ChgDenBit; QtvMax = (QvMax*Factor)>>ChgDenBit In the formula, Factor is the correction factor, ChgDenBit is the energy adjustment coefficient in the denominator, PvMax and QvMax represent the original peak values ​​of the two extended signals, PtvMax and QtvMax represent the corrected peak values ​​of the two extended signals, and >> is the right shift operator.

8. The system according to claim 7, characterized in that, The signal detection module determines the signal detection result based on the corrected peak value and the corrected average value, as well as a pre-set signal detection criterion, wherein the expression for the signal detection criterion is: PtvMax>PwrThr QtvMax>PwrThr PtvAvg>CADRatio QtvAvg>CADRatio In the formula, PtvAvg and QtvAvg represent the corrected peak-to-average ratio of the two extended signals, respectively, and PwrThr and CADRatio represent the absolute peak threshold and peak-to-average ratio threshold, respectively. When all of the signal detection criterion expressions are true, the signal detection result is determined to be successful; when at least one of the signal detection criterion expressions is false, the signal detection result is determined to be unsuccessful.

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