CN116470934A - Method and system for adaptively capturing Chirp signals - Google Patents

Abstract

The invention provides a method and a system for adaptively capturing a Chirp signal, wherein the method comprises the following steps: based on the output gear information of the DAGC, performing amplitude adjustment on the received digital baseband data to obtain correction data; calculating any correction factor according to preset configuration parameters and the output gear information; generating a local Chirp signal which is the same as the Chirp signal of a transmitting end, and generating two paths of expansion signals based on the local Chirp signal; determining the original peak values of the two paths of expansion signals according to the correction data and the two paths of expansion signals; determining correction peaks of two paths of expansion signals according to the correction factors, preset configuration parameters and the original peaks; determining a corrected average value of the correlation energy of the two paths of expansion signals according to the corrected peak value; and determining a signal detection result according to the corrected peak value, the corrected average value and a preset signal detection criterion. The method and the system improve the capturing performance and reduce the false alarm rate.

Description

Method and system for adaptively capturing Chirp signals

Technical Field

The present invention relates to the field of wireless communication technology, and more particularly, to a method and system for adaptively acquiring a Chirp signal.

Background

With the rapid development of wireless communication technology and network technology, the propagation speed and breadth of information have both been improved, and meanwhile, people have put forward higher demands on the aspects of effectiveness, reliability, flexibility, communication range, power consumption of equipment and the like. In the field of wireless spread spectrum, the Chirp spread spectrum technology is widely applied due to the characteristics of good pulse compression characteristic, low complexity, low power consumption, good multipath interference resistance, suitability for long-distance transmission and the like. One of the physical layer standby technologies of the ieee802.15.4 standard was more recently introduced in 2004.

However, with the richness of application fields and scenes of the Chirp technology, people put higher demands on performance, power consumption and the like of wireless communication equipment in burst communication. The detection of energy captured by a wireless signal is an important factor affecting communication performance and power consumption as a first loop of wireless communication. Therefore, in various wireless environments, the problems that the acquisition performance of signal detection is improved, the false alarm rate is reduced, and the high acquisition performance is guaranteed become the problem to be solved for further deepening the application.

Synchronization of spread spectrum systems involves both acquisition and tracking, where acquisition has been a hotspot of research as a key. The synchronous capturing principle of the spread spectrum code is that the related values of the spread spectrum code in 2N phase states are calculated and compared, the capturing state is determined through the capturing threshold judgment, but if the set capturing threshold is too low, the capturing rate can be ensured, but the false alarm rate is improved, and the reliability of the system is reduced; if the threshold is set higher, the reliability of the system is improved, but the capture probability of the system is reduced, and the sensitivity of the system is reduced. Thus, the current typical capture scheme is to use a cumulative algorithm: coherent accumulation, incoherent accumulation and differential coherent accumulation, thereby improving the signal-to-noise ratio of the signal input to the decision module to achieve the sensitivity of the decision module.

In the existing scheme, although the signal to noise ratio is improved based on signal accumulation so as to improve the scheme based on capture threshold judgment, the following disadvantages exist:

the capture scheme based on threshold judgment usually adopts a fixed and single-dimensional capture threshold, if strong out-of-band interference exists, because the amplification factor of the analog automatic gain control AAGC (Analog Automatic Gain Control) takes the interference signal as a reference, the effective signal cannot realize the expected amplification factor, the amplitude of the quantized data signal is reduced, the related energy peak value is reduced, and the capture performance of a receiving end is reduced, so that digital automatic gain control DAGC (digital automatic gain control is used as the supplement of AAGC) is needed, the problem that the amplification factor of the useful signal energy is not ideal when the strong out-of-band interference signal exists in the received signal can be well solved, and meanwhile, in the practical application environment, the diversity of the environmental interference, the DAGC gear precision, the difference of hardware such as a receiving antenna and the like are considered, and the power of the signal needs to be subjected to fine adjustment by combining DAGC gear information, thereby ensuring the capture performance.

Disclosure of Invention

In order to solve the problems that a capture scheme based on threshold judgment in the prior art adopts a fixed and single-dimension capture threshold performance is low, the invention provides a method and a system for adaptively capturing Chirp signals.

According to one aspect of the present invention, there is provided a method of adaptively capturing a Chirp signal, the method comprising:

based on the output gear information of the DAGC, performing amplitude adjustment on the received digital baseband data to obtain correction data;

calculating any correction factor according to preset configuration parameters and the output gear information, wherein the configuration parameters comprise a gear adjustment threshold of the DAGC, an energy adjustment coefficient of a denominator, a common value of coefficient molecules and gear steps;

generating a local Chirp signal which is the same as the Chirp signal of a transmitting end, and generating two paths of expansion signals based on the local Chirp signal;

based on a fast Fourier transform FFT algorithm, realizing circumferential autocorrelation processing of the correction data and the two paths of expansion signals, and determining respective original peaks of the two paths of expansion signals;

correcting the original peak values of the two paths of expansion signals according to the correction factors and preset configuration parameters to obtain respective corrected peak values;

determining a corrected average value of the correlated energy after the left and right m energies centered on the corrected peak value are removed from each of the two paths of expansion signals according to the corrected peak value;

and determining a signal detection result according to the corrected peak value, the corrected average value and a preset signal detection criterion.

Optionally, the calculating any correction factor according to the preset configuration parameter and the output gear information includes:

when the output gear information is smaller than or equal to the gear adjustment threshold, calculating a correction factor, wherein the calculation formula of the correction factor is as follows:

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

in the formula, factor is a correction Factor, chgDenBit is an energy adjustment coefficient of denominator, pwrChgCom is a common value of coefficient molecules, step is gear Step, and < is an operator representing left shift.

Optionally, the generating a local Chirp signal identical to the local Chirp signal of the transmitting end, and generating two paths of extension signals based on the local Chirp signal includes:

generating a local Chirp signal by adopting a local Chirp signal generator;

sampling the local Chrip signal to obtain sampling data, wherein the sampling data comprises N chips;

the sampled data are equally divided front and back, two paths of extension signals are generated through zero padding extension processing of the tail part and the front part, the extension signals are sequences with the length of N, and the expression is as follows:

where preamchorip is the sampled data and PChrip and qcrip are the two-way spread signals.

Optionally, the correcting the original peak values of the two paths of the extension signals according to the correcting factor and a preset configuration parameter to obtain respective corrected peak values, wherein the formula for determining the corrected peak values is as follows:

PtvMax＝(PvMax*Factor)>>ChgDenBit；

QtvMax＝(QvMax*Factor)>>ChgDenBit

In the formula, factor is a correction Factor, chgDenBit is an energy adjustment coefficient of a denominator, pvMax and QvMax respectively represent original peaks of two paths of extension signals, ptvMax and QtvMax respectively represent correction peaks of two paths of extension signals, step is a gear Step, and > is an operator representing right shift.

Optionally, the determining the signal detection result according to the corrected peak value and the corrected average value and a preset signal detection criterion includes:

calculating the respective correction peak-to-average ratio of the two paths of expansion signals according to the correction peak value and the correction average value;

determining a signal detection result according to the corrected peak value, the corrected peak-to-average ratio and a preset signal detection criterion, wherein the signal detection criterion has the following expression:

PtvMax＞PwrThr

QtvMax＞PwrThr

PtvAvg＞CADRatio

QtvAvg＞CADRatio

wherein PtvAvg and QtvAvg respectively represent the corrected peak-to-average ratio of two paths of expansion signals;

and when at least one of the signal detection criterion expressions is not established, determining that the signal detection result is detection failure.

According to another aspect of the present invention, there is provided a system for adaptively acquiring a Chirp signal, the system comprising:

The data correction module is used for carrying out amplitude adjustment on the received digital baseband data based on the output gear information of the DAGC to obtain correction data;

the correction factor module is used for calculating any correction factor according to preset configuration parameters and the output gear information, wherein the configuration parameters comprise a gear adjustment threshold of the DAGC, an energy adjustment coefficient of a denominator, a common value of coefficient molecules and gear steps;

the extended signal module is used for generating a local Chirp signal which is the same as the Chirp signal of the transmitting end and generating two paths of extended signals based on the local Chirp signal;

the signal despreading module is used for realizing circumferential autocorrelation processing of the correction data and the two paths of expansion signals based on a fast Fourier transform FFT algorithm and determining respective original peak values of the two paths of expansion signals;

the peak value correction module is used for correcting the original peak values of the two paths of expansion signals according to the correction factors and preset configuration parameters to obtain respective correction peak values;

the energy mean module is used for determining a corrected mean value of the correlated energy after the left and right m energies taking the corrected peak value as the center are removed from each of the two paths of expansion signals according to the corrected peak value;

And the signal detection module is used for determining a signal detection result according to the corrected peak value, the corrected average value and a preset signal detection criterion.

Optionally, the correction factor module calculates any correction factor according to a preset configuration parameter and the output gear information, including:

when the output gear information is smaller than or equal to the gear adjustment threshold, calculating a correction factor, wherein the calculation formula of the correction factor is as follows:

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

in the formula, factor is a correction Factor, chgDenBit is an energy adjustment coefficient of denominator, pwrChgCom is a common value of coefficient molecules, step is gear Step, and < is an operator representing left shift.

Optionally, the extended signal module generates a local Chirp signal identical to the Chirp signal of the transmitting end, and generates two paths of extended signals based on the local Chirp signal, including:

generating a local Chirp signal by adopting a local Chirp signal generator;

sampling the local Chrip signal to obtain sampling data, wherein the sampling data comprises N chips;

the sampled data are equally divided front and back, two paths of extension signals are generated through zero padding extension processing of the tail part and the front part, the extension signals are sequences with the length of N, and the expression is as follows:

Where preamchorip is the sampled data and PChrip and qcrip are the two-way spread signals.

Optionally, the peak value correction module corrects the original peak values of the two paths of expansion signals according to the correction factors and preset configuration parameters to obtain respective corrected peak values, wherein the formula for determining the corrected peak values is as follows:

PtvMax＝(PvMax*Factor)>>ChgDenBit；

QtvMax＝(QvMax*Factor)>>ChgDenBit

in the formula, factor is a correction Factor, chgDenBit is an energy adjustment coefficient of a denominator, pvMax and QvMax respectively represent original peaks of two paths of extension signals, ptvMax and QtvMax respectively represent correction peaks of two paths of extension signals, step is a gear Step, and > is an operator representing right shift.

Optionally, the signal detection module determines a signal detection result according to the corrected peak value and the corrected average value and a preset signal detection criterion, including:

calculating the respective correction peak-to-average ratio of the two paths of expansion signals according to the correction peak value and the correction average value;

determining a signal detection result according to the corrected peak value, the corrected peak-to-average ratio and a preset signal detection criterion, wherein the signal detection criterion has the following expression:

PtvMax＞PwrThr

QtvMax＞PwrThr

PtvAvg＞CADRatio

QtvAvg＞CADRatio

wherein PtvAvg and QtvAvg respectively represent the corrected peak-to-average ratio of two paths of expansion signals;

And when at least one of the signal detection criterion expressions is not established, determining that the signal detection result is detection failure.

The technical scheme of the invention provides a method and a system for adaptively capturing Chirp signals, wherein the method comprises the following steps: based on the output gear information of the DAGC, performing amplitude adjustment on the received digital baseband data to obtain correction data; calculating any correction factor according to preset configuration parameters and the output gear information; generating a local Chirp signal which is the same as the Chirp signal of a transmitting end, and generating two paths of expansion signals based on the local Chirp signal; based on a fast Fourier transform FFT algorithm, realizing circumferential autocorrelation processing of the correction data and the two paths of expansion signals, and determining respective original peaks of the two paths of expansion signals; correcting the original peak values of the two paths of expansion signals according to the correction factors and preset configuration parameters to obtain respective corrected peak values; determining a corrected average value of the correlated energy after the left and right m energies centered on the corrected peak value are removed from each of the two paths of expansion signals according to the corrected peak value; and determining a signal detection result according to the corrected peak value, the corrected average value and a preset signal detection criterion. The method can meet the simple and rapid adjustment scheme of the correction factors under any precision, solves the problem that the energy evaluation fluctuation of the interference signals on the AAGC and the DAGC in the practical application environment affects the capturing performance, and reduces the index requirement on the analog front end in the signal detection to a certain extent; by constructing two paths of strongly correlated local extension chirp signals and combining a multidimensional capture judgment mechanism, the problem of high false alarm rate caused by single judgment is solved, the capture performance is further improved, invalid communication is reduced by reducing the false alarm rate, and low power consumption during signal detection is ensured.

Drawings

Exemplary embodiments of the present invention may be more completely understood in consideration of the following drawings:

FIG. 1 is a flow chart of a method of adaptively capturing Chirp signals in accordance with a preferred embodiment of the present invention;

FIG. 2a is a time-frequency diagram of a preamble Chirp signal according to a preferred embodiment of the present invention;

FIG. 2b is a time-frequency schematic diagram of a PChirp signal in accordance with a preferred embodiment of the present invention;

FIG. 2c is a time-frequency diagram of a QCHipp signal according to a preferred embodiment of the present invention;

FIG. 3a is a graph of the circumferential correlation energy of a PChirp signal with correction data that is noise free but has a 0.4ms timing offset in accordance with a preferred embodiment of the present invention;

FIG. 3b is a graph showing the circumferential correlation energy of the QCirp signal with correction data that is noise free but has a 0.4ms timing offset in accordance with the preferred embodiment of the present invention;

FIG. 4a is a time domain waveform diagram of the PreamChirp data received at a timing offset of 0 in the I-path according to the preferred embodiment of the present invention;

FIG. 4b is a time domain waveform diagram of the preamcharp data received at a timing offset of 0.4ms in the I-path according to the preferred embodiment of the present invention;

FIG. 5a is a time domain waveform diagram of the PreamChirp data received at a timing offset of 0 in accordance with the preferred embodiment of the present invention in the Q path;

FIG. 5b is a time domain waveform diagram of the PreamChirp data received at a timing offset of 0.4ms in the Q path according to the preferred embodiment of the present invention;

FIG. 6a is a time domain waveform of the PreamChirp data received at a timing offset of 0.4ms in the I-path according to the preferred embodiment of the present invention;

FIG. 6b is a time domain waveform of the Pchirp data at I path with a timing offset of 0 in accordance with a preferred embodiment of the present invention;

FIG. 6c is a time domain waveform of Qchirp data at way I with a timing offset of 0 according to a preferred embodiment of the present invention;

fig. 7 is a schematic diagram of the architecture of a system for adaptively capturing Chirp signals according to a preferred embodiment of the present invention.

Detailed Description

The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the examples described herein, which are provided to fully and completely disclose the present invention and fully convey the scope of the invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like elements/components are referred to by like reference numerals.

Unless otherwise indicated, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. In addition, it will be understood that terms defined in commonly used dictionaries should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.

Exemplary method

Fig. 1 is a flow chart of a method of adaptively capturing Chirp signals according to a preferred embodiment of the present invention. As shown in fig. 1, the method according to the preferred embodiment starts in step 101.

In step 101, amplitude adjustment is performed on the received digital baseband data based on the output gear information of the DAGC to obtain correction data.

In step 102, calculating any correction factor according to a preset configuration parameter and the output gear information, wherein the configuration parameter includes a gear adjustment threshold of the DAGC, an energy adjustment coefficient of a denominator, a common value of coefficient molecules, and a gear step.

Preferably, the calculating any correction factor according to the preset configuration parameters and the output gear information includes:

when the output gear information is smaller than or equal to the gear adjustment threshold, calculating a correction factor, wherein the calculation formula of the correction factor is as follows:

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

In the formula, factor is a correction Factor, chgDenBit is an energy adjustment coefficient of denominator, pwrChgCom is a common value of coefficient molecules, step is gear Step, and < is an operator representing left shift.

The calculation formula of the correction Factor in the preferred embodiment fully considers two aspects of flexibility and pointing accuracy of the adjustment Factor in specific implementation, and the output gear of the DAGC is divided into 0-9 gears in table 1a and table 1b, and specific comparison description is given. In table 1a, the adjustment ratio of the absolute peak threshold of each gear is given in four configurations of the parameters [ DagcThr, chgCom, chgDenBit, step ]: peaktrcoef=factor/(2 c hgdenbit). Table 1b shows the peak-to-average ratio threshold adjustment ratio of 1/PeakCoef for table 1a, where the peak-to-average ratio is the ratio of the peak value determined by analyzing the Chirp signal to the energy average value.

As can be seen from table 1a, the peak-to-peak adjustment factor peaktrcoef based on DAGC gear information adopted in the present invention can meet the following factor correction requirements in practical applications:

(1) A parameter DagcThr controlling a DAGC range applicable to the peak adjustment scheme;

(2) The combination setting of the parameters DagcThr, chgCom, chgDenBit realizes the requirement of the size Gap of the adjustment factor between DagcThr and DagcThr+1;

(3) The parameters Step, chgDenBit are combined and set to meet the adjustment requirement of the asynchronous precision PrecStep between DAGC gears;

(4) The combination setting of the parameters DagcThr, chgCom, chgDenBit and Step realizes the integral requirements of Gap size, adjustment factor stepping precision Precstep and adjustment factor span [ Scope-Max, scope-Min ] based on AGC gear adjustment in the practical application environment.

Table 2 finds the demand analysis results based on the configurations of table 1a and table 1 b.

TABLE 2

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

As is well known, DAGC is used as a supplement to AAGC, and can well solve the problem of undesirable amplification factor of useful signal energy caused by the existence of strong out-of-band interference signals in a received signal. The gear size of the DAGC is proportional to the non-ideal degree of the amplification factor of the AAGC, that is, the larger the gear of the DAGC is, the larger the amplification factor required by the data after low-pass filtering is, and the larger the difference between the amplification factor of the AAGC and the ideal amplification factor is. In theory, the two-stage power evaluation and multiplying power scaling of the AAGC and the DAGC ensure that the received signals subjected to despreading have more stable power, but in an actual wireless channel environment, the power of the signals needs to be finely adjusted by combining DAGC gear information in consideration of the diversity of noise in the environment, the DAGC gear precision, the difference of hardware such as a receiving antenna and the like, so that the capturing performance is ensured. According to the invention, the gear information is output according to the DAGC, and the correction factors are calculated by combining with the preset configuration parameters, so that the simple and rapid adjustment of any correction Factor under any precision can be satisfied, the energy evaluation fluctuation of the AAGC and the DAGC in the application environment in which the interference signals exist actually is realized, the power of the signals is adjusted by influencing the conditions of the correlation peak value and the peak-to-average ratio of the signals, and the high performance of signal capturing is ensured.

In step 103, a local Chirp signal identical to the Chirp signal of the transmitting end is generated, and two paths of extension signals are generated based on the local Chirp signal.

Preferably, the generating a local Chirp signal identical to a Chirp signal of a transmitting end, and generating two paths of extension signals based on the local Chirp signal, includes:

generating a local Chirp signal by adopting a local Chirp signal generator;

sampling the local Chrip signal to obtain sampling data, wherein the sampling data comprises N chips;

the sampled data are equally divided front and back, two paths of extension signals are generated through zero padding extension processing of the tail part and the front part, the extension signals are sequences with the length of N, and the expression is as follows:

where preamchorip is the sampled data and PChrip and qcrip are the two-way spread signals.

In the preferred embodiment, the basic parameters for generating the Chirp signal by the transmitting end are configured as follows: bandwidth bw=125 kHz, spreading factor sf=8, symbol period tc=2.048 ms, sampling rate fs=250 kHz, spread signal slope μ=bw/tc= 6.10352e ⁷ The leading Chirp signal is:

in a preferred embodiment, the expression for generating the local Chirp signal c (t) at the local Chirp signal generator is as follows:

In the above-mentioned method, the step of,is an arbitrary initial phase, and in the present embodiment, the value is 0. After a local Chirp generator at a receiving end generates a local Chirp signal, the local Chirp signal is sampled to obtain a PreamChirp signal. By performing front-back equal-ratio separation and zero padding processing on the preamcharp signal, two paths of spreading sequences with the symbol period being Tc and strong correlation with the preamcharp signal, namely spreading signals PChrip and QChrip, can be generated.

Fig. 2a to 2c show the time-frequency diagrams of the preamble Chirp signals, PChrip and qcrip, respectively.

Fig. 2a is a time-frequency diagram of a preamble Chirp signal according to a preferred embodiment of the present invention. As shown in fig. 2a, the preamble Chirp signal is a signal with a symbol period Tc generated according to a set parameter.

Fig. 2b is a time-frequency diagram of the PChirp signal according to the preferred embodiment of the present invention. As shown in fig. 2b, when the front-to-back equal-ratio separation is performed on the front Chirp signal, the obtained PChirp signal is the chip in the front Tc/2 period, and the zero padding is performed in the back Tc/2 period.

Fig. 2c is a time-frequency diagram of the qcirp signal according to the preferred embodiment of the present invention. As shown in fig. 2c, the qcirp signal is a signal obtained by equally dividing the leading Chirp signal from front to back, with the rear Tc/2 period being the chip, and the front Tc/2 period being zero-padded, in contrast to the PChirp signal.

By carrying out front-back equal ratio separation on the local Chirp signals, two paths of expansion signals which are strongly correlated with the received Chirp signals, namely pseudo code sequences PChirp and QChirp, are generated, so that in the despreading correlation processing, the front part and the back part of correction data obtained after correction of the received data are guaranteed to have strong correlation with the PreamChirp signals, the false alarm probability caused by partial correlation is avoided, and the detection accuracy is improved.

In step 104, circumferential autocorrelation processing of the correction data and the two paths of extension signals is implemented based on a fast fourier transform FFT algorithm, and original peaks of the two paths of extension signals are determined.

Fig. 3a is a graph of the circumferential correlation energy of the PChirp signal with correction data that is noise free but has a timing offset of 0.4ms according to a preferred embodiment of the present invention. Fig. 3b is a graph showing the circumferential correlation energy of the corrected data with the qcirp signal without noise but with a 0.4ms timing offset according to the preferred embodiment of the present invention. As shown in fig. 3a and 3b, when the corrected data obtained by amplitude modulation of the digital baseband data received without noise but with a timing deviation of 0.4ms is calculated with local correlation energy peaks of the PChirp signal and the qhirp signal, which are circularly convolved based on FFT, the corrected data has obvious peaks, which indicates that the corrected data and the PChirp signal have good correlation characteristics.

After the front and rear of the PreamChrip signal are equally divided, zero padding is adopted to extend to N length to generate two paths of extension signals PChirp and Qhirp, so that the quick realization of the correction data and the detection of the PChirp and Qhirp related energy based on FFT circle convolution is ensured, and the influence of timing deviation is avoided.

Fig. 4a and 5a show a comparison of the time domain waveforms of the two paths I, Q of preamcharp at a timing deviation tshift=0, respectively, while fig. 4b and 5b show a comparison of the time domain waveforms of the two paths I, Q of preamcharp at a timing deviation tshift=0.4 ms, respectively. Comparing fig. 4a and fig. 4b, it is found that under timing deviation, fig. 4b is equivalent to circumferentially shifting the spreading sequence of fig. 4a, moving the dashed box part to the end of the sequence. Similarly, comparing fig. 5a and fig. 5b, it is found that, under timing deviation, fig. 5b is equivalent to circumferentially shifting the spreading sequence of fig. 5a, with the dashed box portion shifted to the end of the sequence.

Fig. 6a is a time domain waveform of preamcharp data received at a timing deviation of 0.4ms according to a preferred embodiment of the present invention, fig. 6b is a time domain waveform of pcharp data at an I-path according to a preferred embodiment of the present invention at a timing deviation of 0, and fig. 6c is a time domain waveform of Qchirp data at an I-path according to a preferred embodiment of the present invention at a timing deviation of 0, and comparison analysis is performed in conjunction with fig. 6a, 6b, and 6c, which show that a received preamble spreading sequence preamchorip having a timing deviation of 0.4ms needs to be subjected to a circumferential cyclic shift of a certain length to achieve symbol alignment, and has a good correlation peak. Zero padding to PChirp, QChirp is therefore particularly important to extend to N. If zero padding expansion is not performed, the original PChirp, QChirp length is N/2 length, the system can only perform local correlation processing with the length of N/2 length, and only adopts a sliding correlation scheme. Because the FFT-based circumferential correlation, as shown in the large dashed box of fig. 6a, 6b, does not achieve optimal correlation performance, in the limit case, even causes a sharp drop in correlation peak, resulting in missed detection.

According to the implementation mode, the PChirp and Qhirp are subjected to corresponding zero padding of the front end and the rear end until the code length N of the local Chirp signal is reached, after two paths of extension signals PChirp, QChirp are generated, the effect that the circumferential correlation peak value of the correction data and the local pseudo code PChirp, QChirp is not influenced by timing deviation is achieved by adopting FFT, zero padding is not pseudo random code extension, the calculation complexity is effectively reduced, and meanwhile noise of the increase of correlation results is avoided.

In step 105, the original peak values of the two paths of expansion signals are corrected according to the correction factors and preset configuration parameters, so as to obtain respective corrected peak values.

Preferably, the correction is performed on the original peak values of the two paths of extension signals according to the correction factor and a preset configuration parameter to obtain respective correction peak values, wherein the formula for determining the correction peak values is as follows:

PtvMax＝(PvMax*Factor)>>ChgDenBit；

QtvMax＝(QvMax*Factor)>>ChgDenBit

in the formula, factor is a correction Factor, chgDenBit is an energy adjustment coefficient of a denominator, pvMax and QvMax respectively represent original peaks of two paths of extension signals, ptvMax and QtvMax respectively represent correction peaks of two paths of extension signals, step is a gear Step, and > is an operator representing right shift.

In the preferred embodiment, the influence of the energy evaluation fluctuation of the AAGC and the DAGC under various interferences of an application environment on the signal detection is combined, and the peak values of the PChirp and the Qhirp are firstly corrected based on the correction Factor of the DAGC gear, so that the automatic adaptation of an absolute peak value threshold PwrThr and a peak-to-average ratio threshold CADRatio in the signal detection to various DAGC gears is realized, and the reduction of the captured omission ratio is ensured.

In step 106, a corrected average value of the correlation energy after the two paths of expansion signals are respectively removed from the left and right m energies centered on the corrected peak value is determined according to the corrected peak value. In the present preferred embodiment, m is set comprehensively based on the correlation of PChirp and qhirp, and the data acquisition rate.

In step 107, a signal detection result is determined according to the corrected peak value and the corrected average value, and a preset signal detection criterion.

Preferably, the determining the signal detection result according to the corrected peak value and the corrected average value and a preset signal detection criterion includes:

calculating the respective correction peak-to-average ratio of the two paths of expansion signals according to the correction peak value and the correction average value;

determining a signal detection result according to the corrected peak value, the corrected peak-to-average ratio and a preset signal detection criterion, wherein the signal detection criterion has the following expression:

PtvMax＞PwrThr

QtvMax＞PwrThr

PtvAvg＞CADRatio

QtvAvg＞CADRatio

wherein PtvAvg and QtvAvg respectively represent the corrected peak-to-average ratio of two paths of expansion signals;

and when at least one of the signal detection criterion expressions is not established, determining that the signal detection result is detection failure.

In the signal detection, the first two belong to absolute threshold criteria, the second two belong to relative threshold criteria, and the joint judgment of the absolute dimension and the relative dimension is realized through the four criterion expressions, so that the false detection phenomenon caused by that only a single dimension meets the judgment condition is effectively avoided. Meanwhile, by adopting two paths of strong-correlation local pseudo codes PChirp and Qchirp, and the information such as the correction peak value and the correction peak-to-average ratio obtained by calculation, the integral judgment of the front and rear part combined correlation in one symbol period is realized, the false detection phenomenon caused by the local strong correlation is reduced to a certain extent, and the capturing performance is further improved.

In summary, in the preferred embodiment, firstly, the correction factor is calculated based on the DAGC gear information and the set configuration parameters, so that the threshold value of signal detection can be adaptively adjusted, and the capturing performance is improved; secondly, based on a local Chirp signal generated by a local Chirp signal generator, two paths of extension signals with strong correlation with a transmitting end Chirp signal are obtained, so that the corrected data obtained based on the received digital baseband data is guaranteed to have strong correlation with the transmitting end Chirp signal in the whole symbol period, the sliding local cross correlation can be realized by adopting FFT circular convolution, the related calculation complexity is simplified, and the influence of timing deviation is avoided; and thirdly, by setting an absolute threshold criterion and a relative threshold criterion at the same time, the signal detection criterion effectively avoids the false detection phenomenon caused by that only a single dimension meets the judgment condition, and ensures the low false alarm rate.

Exemplary System

Fig. 7 is a schematic diagram of the architecture of a system for adaptively capturing Chirp signals according to a preferred embodiment of the present invention. As shown in fig. 7, a system 700 according to the present preferred embodiment includes:

the data correction module 701 is configured to perform amplitude adjustment on the received digital baseband data based on the output gear information of the DAGC to obtain correction data;

a correction factor module 702, configured to calculate an arbitrary correction factor according to a preset configuration parameter and the output gear information, where the configuration parameter includes a gear adjustment threshold of the DAGC, an energy adjustment coefficient of a denominator, a common value of coefficient molecules, and a gear step;

the extended signal module 703 is configured to generate a local Chirp signal identical to a Chirp signal of the transmitting end, and generate two paths of extended signals based on the local Chirp signal;

a signal despreading module 704, configured to implement circumferential autocorrelation processing of the correction data and the two paths of spread signals based on a fast fourier transform FFT algorithm, and determine respective original peaks of the two paths of spread signals;

the peak value correction module 705 is configured to correct the original peak values of the two paths of extension signals according to the correction factors and preset configuration parameters, so as to obtain respective corrected peak values;

An energy mean module 706, configured to determine, according to the correction peak value, a correction mean value of correlation energies after the two paths of extension signals each remove left and right m energies centered on the correction peak value;

and the signal detection module 707 is configured to determine a signal detection result according to the corrected peak value and the corrected average value, and a preset signal detection criterion.

Preferably, the correction factor module 702 calculates any correction factor according to a preset configuration parameter and the output gear information, including:

when the output gear information is smaller than or equal to the gear adjustment threshold, calculating a correction factor, wherein the calculation formula of the correction factor is as follows:

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

in the formula, factor is a correction Factor, chgDenBit is an energy adjustment coefficient of denominator, pwrChgCom is a common value of coefficient molecules, step is gear Step, and < is an operator representing left shift.

Preferably, the extended signal module 703 generates a local Chirp signal identical to a Chirp signal of a transmitting end, and generates two paths of extended signals based on the local Chirp signal, including:

generating a local Chirp signal by adopting a local Chirp signal generator;

sampling the local Chrip signal to obtain sampling data, wherein the sampling data comprises N chips;

The sampled data are equally divided front and back, two paths of extension signals are generated through zero padding extension processing of the tail part and the front part, the extension signals are sequences with the length of N, and the expression is as follows:

where preamchorip is the sampled data and PChrip and qcrip are the two-way spread signals.

Preferably, the peak value correction module 705 corrects the original peak values of the two paths of the extension signals according to the correction factor and a preset configuration parameter to obtain respective corrected peak values, where the formula for determining the corrected peak values is as follows:

PtvMax＝(PvMax*Factor)>>ChgDenBit；

QtvMax＝(QvMax*Factor)>>ChgDenBit

in the formula, factor is a correction Factor, chgDenBit is an energy adjustment coefficient of a denominator, pvMax and QvMax respectively represent original peaks of two paths of extension signals, ptvMax and QtvMax respectively represent correction peaks of two paths of extension signals, step is a gear Step, and > is an operator representing right shift.

Preferably, the signal detection module 707 determines a signal detection result according to the corrected peak value and the corrected average value, and a preset signal detection criterion, including:

calculating the respective correction peak-to-average ratio of the two paths of expansion signals according to the correction peak value and the correction average value;

determining a signal detection result according to the corrected peak value, the corrected peak-to-average ratio and a preset signal detection criterion, wherein the signal detection criterion has the following expression:

PtvMax＞PwrThr

QtvMax＞PwrThr

PtvAvg＞CADRatio

QtvAvg＞CADRatio

Wherein PtvAvg and QtvAvg respectively represent the corrected peak-to-average ratio of two paths of expansion signals;

and when at least one of the signal detection criterion expressions is not established, determining that the signal detection result is detection failure.

The system for adaptively capturing a Chirp signal according to the preferred embodiment performs amplitude modulation on received digital baseband data to generate correction data, adaptively adjusts a threshold value of a signal detection criterion by acquiring any correction factor, generates two paths of extension signals having strong correlation with a Chirp signal at a transmitting end, performs circumferential autocorrelation processing on the correction data and the two paths of extension signals based on a fast fourier transform FFT algorithm, determines respective original peaks of the two paths of extension signals, corrects the original peaks to obtain correction peaks, and performs signal detection through the signal detection criterion in the same manner as the step of the method for adaptively capturing the Chirp signal according to the present invention, which achieves the same technical effects and is not repeated herein.

The invention has been described with reference to a few embodiments. However, as is well known to those skilled in the art, other embodiments than the above disclosed invention are equally possible within the scope of the invention, as defined by the appended patent claims.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise therein. All references to "a/an/the [ means, component, etc. ]" are to be interpreted openly as referring to at least one instance of said means, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may 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, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Finally, it should be noted that: the above embodiments are only for illustrating the technical aspects of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above embodiments, it should be understood by those of ordinary skill in the art that: modifications and equivalents may be made to the specific embodiments of the invention without departing from the spirit and scope of the invention, which is intended to be covered by the claims.

Claims (10)

1. A method of adaptively acquiring a Chirp signal, the method comprising:

based on the output gear information of the DAGC, performing amplitude adjustment on the received digital baseband data to obtain correction data;

calculating any correction factor according to preset configuration parameters and the output gear information, wherein the configuration parameters comprise a gear adjustment threshold of the DAGC, an energy adjustment coefficient of a denominator, a common value of coefficient molecules and gear steps;

generating a local Chirp signal which is the same as the Chirp signal of a transmitting end, and generating two paths of expansion signals based on the local Chirp signal;

based on a fast Fourier transform FFT algorithm, realizing circumferential autocorrelation processing of the correction data and the two paths of expansion signals, and determining respective original peaks of the two paths of expansion signals;

correcting the original peak values of the two paths of expansion signals according to the correction factors and preset configuration parameters to obtain respective corrected peak values;

determining a corrected average value of the correlated energy after the left and right m energies centered on the corrected peak value are removed from each of the two paths of expansion signals according to the corrected peak value;

and determining a signal detection result according to the corrected peak value, the corrected average value and a preset signal detection criterion.

2. The method of claim 1, wherein calculating any correction factor based on the preset configuration parameters and the output gear information comprises:

when the output gear information is smaller than or equal to the gear adjustment threshold, calculating a correction factor, wherein the calculation formula of the correction factor is as follows:

factor= (1 < < ChgDenBit) -pwrchgcom+ (PwrChgCom-DagcThr) in Step formula, factor is a correction Factor, chgDenBit is an energy adjustment coefficient of denominator, pwrChgCom is a common value of coefficient molecules, step is a gear Step, and < is an operator representing left shift.

3. The method according to claim 1, wherein generating a local Chirp signal identical to a Chirp signal of a transmitting side and generating two paths of extension signals based on the local Chirp signal comprises:

generating a local Chirp signal by adopting a local Chirp signal generator;

sampling the local Chrip signal to obtain sampling data, wherein the sampling data comprises N chips;

the sampled data are equally divided front and back, two paths of extension signals are generated through zero padding extension processing of the tail part and the front part, the extension signals are sequences with the length of N, and the expression is as follows:

Where preamchorip is the sampled data and PChrip and qcrip are the two-way spread signals.

4. The method of claim 1, wherein the correcting the original peak values of the two paths of the extension signals according to the correction factor and the preset configuration parameter to obtain the respective corrected peak values, and the formula for determining the corrected peak values is as follows:

PtvMax＝(PvMax*Factor)>>ChgDenBit；

QtvMax＝(QvMax*Factor)>>ChgDenBit

in the formula, factor is a correction Factor, chgDenBit is an energy adjustment coefficient of a denominator, pvMax and QvMax respectively represent original peaks of two paths of extension signals, ptvMax and QtvMax respectively represent correction peaks of two paths of extension signals, step is a gear Step, and > is an operator representing right shift.

5. The method of claim 4, wherein said determining a signal detection result based on said modified peak value and modified average value, and a preset signal detection criterion, comprises:

calculating the respective correction peak-to-average ratio of the two paths of expansion signals according to the correction peak value and the correction average value;

determining a signal detection result according to the corrected peak value, the corrected peak-to-average ratio and a preset signal detection criterion, wherein the signal detection criterion has the following expression:

PtvMax＞PwrThr

QtvMax＞PwrThr

PtvAvg＞CADRatio

QtvAvg＞CADRatio

Wherein PtvAvg and QtvAvg respectively represent the corrected peak-to-average ratio of two paths of expansion signals;

and when at least one of the signal detection criterion expressions is not established, determining that the signal detection result is detection failure.

6. A system for adaptively acquiring a Chirp signal, the system comprising:

the data correction module is used for carrying out amplitude adjustment on the received digital baseband data based on the output gear information of the DAGC to obtain correction data;

the correction factor module is used for calculating any correction factor according to preset configuration parameters and the output gear information, wherein the configuration parameters comprise a gear adjustment threshold of the DAGC, an energy adjustment coefficient of a denominator, a common value of coefficient molecules and gear steps;

the extended signal module is used for generating a local Chirp signal which is the same as the Chirp signal of the transmitting end and generating two paths of extended signals based on the local Chirp signal;

the signal despreading module is used for realizing circumferential autocorrelation processing of the correction data and the two paths of expansion signals based on a fast Fourier transform FFT algorithm and determining respective original peak values of the two paths of expansion signals;

The peak value correction module is used for correcting the original peak values of the two paths of expansion signals according to the correction factors and preset configuration parameters to obtain respective correction peak values;

the energy mean module is used for determining a corrected mean value of the correlated energy after the left and right m energies taking the corrected peak value as the center are removed from each of the two paths of expansion signals according to the corrected peak value;

and the signal detection module is used for determining a signal detection result according to the corrected peak value, the corrected average value and a preset signal detection criterion.

7. The system of claim 6, wherein the correction factor module calculates any correction factor based on preset configuration parameters and the output gear information, comprising:

when the output gear information is smaller than or equal to the gear adjustment threshold, calculating a correction factor, wherein the calculation formula of the correction factor is as follows:

factor= (1 < < ChgDenBit) -pwrchgcom+ (PwrChgCom-DagcThr) in Step formula, factor is a correction Factor, chgDenBit is an energy adjustment coefficient of denominator, pwrChgCom is a common value of coefficient molecules, step is a gear Step, and < is an operator representing left shift.

8. The system of claim 6, wherein the spread signal module generates a local Chirp signal identical to a Chirp signal of a transmitting end and generates two paths of spread signals based on the local Chirp signal, comprising:

Generating a local Chirp signal by adopting a local Chirp signal generator;

sampling the local Chrip signal to obtain sampling data, wherein the sampling data comprises N chips;

the sampled data are equally divided front and back, two paths of extension signals are generated through zero padding extension processing of the tail part and the front part, the extension signals are sequences with the length of N, and the expression is as follows:

where preamchorip is the sampled data and PChrip and qcrip are the two-way spread signals.

9. The system of claim 6, wherein the peak value correction module corrects the original peak values of the two paths of the extended signals according to the correction factors and the preset configuration parameters to obtain respective corrected peak values, and the formula for determining the corrected peak values is as follows:

PtvMax＝(PvMax*Factor)>>ChgDenBit；

QtvMax＝(QvMax*Factor)>>ChgDenBit

in the formula, factor is a correction Factor, chgDenBit is an energy adjustment coefficient of a denominator, pvMax and QvMax respectively represent original peaks of two paths of extension signals, ptvMax and QtvMax respectively represent correction peaks of two paths of extension signals, step is a gear Step, and > is an operator representing right shift.

10. The system of claim 9, wherein the signal detection module determines a signal detection result based on the modified peak value and the modified average value, and a preset signal detection criterion, comprising:

Calculating the respective correction peak-to-average ratio of the two paths of expansion signals according to the correction peak value and the correction average value;

determining a signal detection result according to the corrected peak value, the corrected peak-to-average ratio and a preset signal detection criterion, wherein the signal detection criterion has the following expression:

PtvMax＞PwrThr

QtvMax＞PwrThr

PtvAvg＞CADRatio

QtvAvg＞CADRatio

wherein PtvAvg and QtvAvg respectively represent the corrected peak-to-average ratio of two paths of expansion signals;

and when at least one of the signal detection criterion expressions is not established, determining that the signal detection result is detection failure.