CN117811596B - Passive wireless signal coherence judging and transmitting method and system - Google Patents
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Abstract
The invention discloses a method and a system for judging and transmitting the coherence of a passive wireless signal. The problem that the existing MDFC sensing system is easy to be interfered by the same-frequency signals which occur randomly is solved. And by further carrying out matched filtering according to the number sequence, all received signals can be processed while the processing efficiency is considered, and the problem that the signals cannot be received outside the predicted frequency band is avoided.
Description
Technical Field
The invention relates to the technical field of wireless communication, in particular to a passive wireless signal coherence judging and transmitting method and system.
Background
The microwave direct drive frequency conversion (Microwave Driven Frequency Conversion, MDFC) technology can realize the function of passive frequency conversion of specific microwaves in special materials, and the principle can be referred to in the prior application (patent number: ZL 202310112908.0). The sensor using the technology has the characteristics of immediate response after being driven, different frequency and mutual noninterference of the variable frequency signal and the driving signal, same time width, bandwidth and repetition period, and modulation by the resonance frequency.
When the MDFC technology is used, a transceiver transmits a driving signal, and when the MDFC sensor meets the driving power, the MDFC sensor generates a response signal with different frequencies, and the transceiver receives the response signal and calculates the sensing quantity. However, when there is an interference signal in the space that overlaps or is close to the frequency of the response signal, the transceiver receives the interference signal, causing the receiver to calculate erroneous information.
Disclosure of Invention
The invention overcomes the defect that the driven signals of the MDFC sensor in the prior art possibly have frequency overlapping or similar, and provides a passive wireless signal coherence judging and transmitting method and system, so as to be expected to solve the problems in the prior art.
In order to solve the technical problems described above, an aspect of the present invention provides a passive wireless signal coherence judging and transmitting method:
a passive wireless signal coherence judging and transmitting method comprises the following steps:
s1: the transceiver transmits a microwave driving signal;
s2: the transceiver receives the microwave signal in the space;
s3: the transceiver performs matched filtering on the received microwave signals;
s4: the transceiver judges a driven signal of the driving signal according to whether the received microwave signal and the driving signal have correlation;
S5: and calculating and analyzing the driven signal, and demodulating and recovering transmission information.
When the MDFC technology is used, a transceiver transmits a driving signal, when the MDFC sensor meets the driving power, the MDFC sensor generates a response signal with different frequencies, the transceiver receives the response signal and calculates the sensing quantity, but when interference f t similar to f r1 randomly occurs in space (as shown in fig. 2), the transceiver cannot distinguish whether f r1 or f t is a driven return signal generated by the sensor, so that calculation errors are caused.
Since the driven return signal f rn of the MDFC has a strong correlation with the microwave driving signal f 0, the frequency variation characteristic of the driven return signal is identical to that of the driving signal, and the time width, bandwidth and repetition period of the driven return signal are correspondingly identical to those of the driving signal.
The invention carries out the matched filtering on the received signals, carries out the correlation analysis by taking the driving signals as the reference, judges the signals with high correlation as the driven return signals of the sensor, can identify the driven signals from the interference signals, and carries out the analysis and calculation on the signals with the frequency to restore the sensing information.
The further technical scheme is that S1 is specifically that a transceiver transmits a modulated microwave driving signal;
the modulation mode comprises one or more of frequency modulation, phase modulation, amplitude modulation and linear frequency modulation.
In a further technical scheme, S3 is specifically that the transceiver uses a matched filter, and processes the received signal with reference to the characteristics of the driving signal.
The further technical scheme is that the S2 specifically is:
s21: the transceiver predicts the frequency range of the driven signal according to the use condition;
S22: the transceiver receives microwave signals within a predicted frequency band of the driven signal in space.
In a specific use environment, the approximate frequency range of the driven signal is expected, so that only signals in a predicted frequency band can be received, and matched filtering and correlation judgment are carried out on the received signals, so that fewer interference signals fall into a detection bandwidth, the number of signals needing to be subjected to matched filtering and correlation judgment is fewer, the processing time can be shortened, and the signal processing efficiency is improved.
The further technical scheme is that the S2 specifically is:
s21: the transceiver predicts the frequency range of the driven signal according to the use condition;
S22: the transceiver numbers the received signals, the signal number close to the predicted result is front, and the signal number far away from the predicted result is back;
The step S3 is specifically that the transceiver carries out matched filtering on the received microwave signals according to the serial number sequence.
If only signals within the predicted frequency band are received, although the signal processing efficiency can be improved, if signals outside the predicted frequency band occur, they cannot be received. By numbering the received signals in the order close to the predicted result and performing matched filtering in the order of the numbers, all the received signals can be processed while the processing efficiency is considered, and the problem that the signals cannot be received outside the predicted frequency band is avoided.
In a further technical scheme, the step S4 is specifically that the transceiver performs correlation judgment on the matched and filtered microwave signals to judge whether the matched and filtered microwave signals are driven signals or not;
if the signal is not the driven signal, carrying out S3 matched filtering processing on the next signal, and repeating S3-S4 on the residual signal until the signal is judged to be the driven signal;
If the determination is a driven signal, S5 is entered.
In a further technical scheme, in the step S4, if a plurality of microwave signals received by the transceiver have correlation with the driving signal;
Stopping executing the subsequent steps;
The transceiver transmits the differently modulated microwave drive signals, performing the steps S2-S5.
In extreme cases, there may be a situation where multiple driven signals have correlation with the modulated driving signals, and at this time, the modulation mode of the driving signals needs to be changed to avoid interference.
The invention also provides a passive wireless signal coherence judging and transmitting system.
A passive wireless signal coherence judging and transmitting system comprises a transceiver and a microwave direct-drive variable-frequency sensor;
the microwave direct-drive variable frequency sensor is used for receiving the driving signal and generating driven signals with different frequencies;
The transceiver is used for sending out a driving signal, receiving a driven signal, carrying out matched filtering on the driven signal, judging a receiving signal of the driving signal and restoring the driven signal into tested data.
The further technical scheme is that the transceiver can modulate the microwave driving signal and then send the microwave driving signal.
Compared with the prior art, the invention has at least the following beneficial effects: the invention carries out the matched filtering on the received signals, carries out the correlation analysis by taking the driving signals as the reference, judges the signals with high correlation as the sensor driven return signals, carries out the analysis and calculation on the signals with the frequency, and restores the sensing information. The driven signal can be identified from the interference signal, and the problem that the existing MDFC sensing system is easy to be interfered by the same-frequency signal which occurs randomly is solved. And by further carrying out matched filtering according to the number sequence, all received signals can be processed while the processing efficiency is considered, and the problem that the signals cannot be received outside the predicted frequency band is avoided.
Drawings
FIG. 1 is a graph of a driven return signal spectrum;
FIG. 2 is a graph of driven return signal and interference signal spectra;
FIG. 3 is a flow chart of an embodiment;
FIG. 4 is a driven return signal and interference signal modulation process;
FIG. 5 is a schematic flow chart of an embodiment.
Detailed Description
The present invention will be described in further detail with reference to the following examples in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
The MDFC system works in that the transceiver emits a microwave driving signal with frequency f 0, and the sensor generates a driven return signal with frequency f rn when receiving the driving signal of f 0, see fig. 1, where n=1, 2,3, … …, f c is the resonant frequency of the resonant device inside the sensor, and the mirror image spectrum f rn' is also generated on the symmetrical side of f 0.
If the transceiver gateway in the system selects the signal with frequency f r1 as the sensor detection signal, the transceiver receives and analyzes the signal f r1 and calculates the sensing data.
However, when the interference f t similar to the interference f r1 appears randomly in the space, referring to fig. 2, the transceiver cannot distinguish whether f r1 or f t is the driven return signal generated by the sensor, resulting in a calculation error.
Embodiment one:
a passive wireless signal coherence judging and transmitting method, referring to fig. 1, comprises the following steps:
s1: the transceiver transmits a microwave driving signal;
In this embodiment, the S1 is specifically that the transceiver transmits a modulated microwave driving signal;
The transceiver transmits a microwave driving signal, the carrier wave of the microwave driving signal is f 0, and the modulation modes of the signal can be a plurality of modulation modes such as frequency modulation, phase modulation, amplitude modulation, linear frequency modulation and the like.
The expression of the frequency modulated continuous wave drive signal used by the transceiver is:；
f 0 denotes the drive signal carrier frequency;
phi (t) represents the modulation function of the drive signal;
t represents time;
The sensor is arranged to receive f 0 and at the same time generate a driven return signal of carrier frequency f r1 (hereinafter the drive signal is denoted as f r1) which has a strong coherence with the drive signal, i.e. the same modulation scheme, but the carrier is changed relative to the drive signal.
The frequency of different driven signals generated by the sensor is f rn=f0±n·fc, wherein n=1, 2,3 … … and f c are the resonance frequency of the internal resonance device of the sensor, and the resonance frequency of the internal resonance device of the sensor changes along with the change of the test quantity, so that the test quantity can be obtained by calculating the frequency change quantity of f c and the driven signals.
S2: the transceiver receives the microwave signal in the space;
In this embodiment, S2 specifically includes the following steps:
s21: the transceiver predicts the frequency range of the driven signal according to the use condition;
S22: the transceiver receives microwave signals within a predicted frequency band of the driven signal in space.
The frequency of the driven signal is predictable for the sensor. The sensor may be a temperature sensor, a pressure sensor, a humidity sensor, etc.
Taking a temperature sensor as an example, the temperature sensor is arranged at a specific position, the temperature fluctuation of the position has a certain range, the influence of the temperature fluctuation on the resonance frequency of a resonance device in the sensor can be predicted, and the data processing capacity of the subsequent steps is reduced and the transmission efficiency is improved by only receiving microwave signals in a predicted frequency band.
S3: the transceiver performs matched filtering on the received microwave signals;
When the transceiver receives the driven return signal of f r1 and then performs signal processing, a matched filter is used to process the received signal with reference to the characteristics of the drive signal. At this time, after the driven return signal with better coherence with the driving signal is processed, a higher signal amplitude is obtained, and the interference signal with lower coherence is obtained, and the processed signal amplitude is lower, so that the interference signal is distinguished, and signal interference is avoided.
Specifically, a driven return signal matched filtering function is designed to be h r (t-t) according to a transmitting signal;
Wherein t represents a time delay corresponding to a double-pass distance between the transceiver and the sensor;
The expression of the matched filtering algorithm of the driven return signal is ；
Wherein f rn (t) represents the driven return signal;
And respectively carrying out matched filtering processing on each signal which is possibly a driven return signal in the last step, analyzing and processing the filtering result, and outputting a signal filtering result.
Referring to fig. 4, where s (t) is the driven return signal, n (t) is the interference signal, H (ω) is the frequency domain representation of the matched filtering algorithm, s 0 (t) is the driven return signal matched filtered signal, n 0 (t) is the interference signal matched filtered signal, and s 0 (t) is much larger in amplitude than n 0 (t).
S4: the transceiver judges a driven signal of the driving signal according to whether the received microwave signal and the driving signal have correlation;
since the correlation determination is performed on the amplitudes of the interference signal and the driven return signal after the filtering process, in this embodiment, the matching filtering and the correlation determination are performed on all the signals.
If a plurality of microwave signals received by the transceiver have correlation with the driving signal;
Then an interference signal is indicated, and the execution of the subsequent steps is stopped at the moment;
The transceiver re-transmits the microwave driving signals which are modulated differently, and the steps S2-S5 are executed, at this time, the modulation mode of the microwave driving signals is different from that of the last microwave driving signals, and the modulation mode of the returned driven signals is also different, so that interference with other signals is avoided.
S5: and calculating and analyzing the driven signal, and demodulating and recovering transmission information.
The resonance frequency of the sensor internal resonance device can be obtained through calculation, the resonance frequency of the sensor internal resonance device changes along with the change of the test quantity, and therefore the test quantity can be obtained through calculation of the resonance frequency of the internal resonance device and the frequency change quantity of the driven signal.
Embodiment two:
The passive wireless signal coherence judging and transmitting method, see fig. 2, comprises the following steps:
s1: the transceiver transmits a microwave driving signal;
In this embodiment, the S1 is specifically that the transceiver transmits a modulated microwave driving signal;
The transceiver transmits a microwave driving signal, the carrier wave of the microwave driving signal is f 0, and the modulation modes of the signal can be a plurality of modulation modes such as frequency modulation, phase modulation, amplitude modulation, linear frequency modulation and the like.
S2: the transceiver receives the microwave signal in the space;
In this embodiment, the S2 specifically is:
s21: the transceiver predicts the frequency range of the driven signal according to the use condition;
S22: the transceiver numbers the received signals, the signal number close to the predicted result is front, and the signal number far away from the predicted result is back;
In this embodiment, in order to avoid missing detection of the driving signal while improving efficiency, the transceiver receives all signals and numbers the received signals. Also taking a temperature sensor as an example, due to the temperature sensor at a specific location, its most likely measured temperature can be predicted, converting the most likely measured temperature to the most likely returned driven signal frequency.
For all received signals, the signal number close to the most likely returned driven signal frequency is front, and the signal number far away from the most likely returned driven signal frequency is back;
s3: the transceiver performs matched filtering on the received microwave signals;
The transceiver performs matched filtering on the received microwave signals according to the serial number sequence.
S4: the transceiver judges a driven signal of the driving signal according to whether the received microwave signal and the driving signal have correlation;
The transceiver carries out correlation judgment on the microwave signals after the matching and filtering, and judges whether the microwave signals are driven signals or not;
if the signal is not the driven signal, carrying out S3 matched filtering processing on the next signal, and repeating S3-S4 on the residual signal until the signal is judged to be the driven signal;
If the determination is a driven signal, S5 is entered.
S5: and calculating and analyzing the driven signal, and demodulating and recovering transmission information.
Embodiment III:
a passive wireless signal coherence judging and transmitting system comprises a transceiver and a microwave direct-drive variable-frequency sensor;
the microwave direct-drive variable frequency sensor is used for receiving the driving signal and generating driven signals with different frequencies;
The transceiver is used for modulating the microwave driving signal and then sending out the microwave driving signal, receiving the driven signal, carrying out matched filtering on the driven signal, judging the receiving signal of the driving signal, and restoring the driven signal into the tested data.
Although the application has been described herein with reference to illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the scope and spirit of the principles of this disclosure. More specifically, various modifications and improvements may be made to the component parts and/or arrangements of the subject combination layout within the scope of the disclosure. In addition to variations and modifications in the component parts and/or arrangements, other uses will be apparent to those skilled in the art.
Claims (9)
1. A passive wireless signal coherence judging and transmitting method is characterized by comprising the following steps:
s1: the transceiver transmits a microwave driving signal;
s2: the transceiver receives the microwave signal in the space;
s3: the transceiver performs matched filtering on the received microwave signal by taking the characteristic of the driving signal as a reference;
s4: the transceiver judges a driven signal of the driving signal according to the correlation between a matched filtering result of the received microwave signal and whether the driving signal has a characteristic taking the driving signal as a reference;
S5: and calculating and analyzing the driven signal, and demodulating and recovering transmission information.
2. The method for determining and transmitting coherence of a passive wireless signal according to claim 1, wherein S1 is specifically that a transceiver transmits a modulated microwave driving signal;
the modulation mode comprises one or more of frequency modulation, phase modulation, amplitude modulation and linear frequency modulation.
3. The method of claim 1, wherein S3 is specifically that the transceiver uses a matched filter to process the received signal based on characteristics of the driving signal.
4. The method for determining and transmitting coherence of a passive wireless signal according to claim 1, wherein S2 specifically comprises:
s21: the transceiver predicts the frequency range of the driven signal according to the use condition;
S22: the transceiver receives microwave signals within a predicted frequency band of the driven signal in space.
5. The method for determining and transmitting coherence of a passive wireless signal according to claim 1, wherein S2 specifically comprises:
s21: the transceiver predicts the frequency range of the driven signal according to the use condition;
S22: the transceiver numbers the received signals, the signal number close to the predicted result is front, and the signal number far away from the predicted result is back;
The step S3 is specifically that the transceiver carries out matched filtering on the received microwave signals according to the serial number sequence.
6. The method for determining and transmitting coherence of a passive wireless signal according to any one of claims 4-5, wherein S4 is specifically that the transceiver performs correlation determination on the matched and filtered microwave signal to determine whether the matched and filtered microwave signal is a driven signal;
if the signal is not the driven signal, carrying out S3 matched filtering processing on the next signal, and repeating S3-S4 on the residual signal until the signal is judged to be the driven signal;
If the determination is a driven signal, S5 is entered.
7. The method for determining and transmitting coherence of a passive wireless signal according to claim 1, wherein in S4, if there are a plurality of microwave signals received by the transceiver and the driving signal have correlation;
Stopping executing the subsequent steps;
The transceiver transmits the differently modulated microwave drive signals, performing the steps S2-S5.
8. The passive wireless signal coherence judging and transmitting system is characterized by comprising a transceiver and a microwave direct-drive variable-frequency sensor;
the microwave direct-drive variable frequency sensor is used for receiving the driving signal and generating driven signals with different frequencies;
The transceiver is used for sending out a driving signal, receiving the driven signal, carrying out matched filtering on the driven signal by taking the characteristic of the driving signal as a reference, judging the driven signal of the driving signal according to the correlation between the matched filtering result of the received microwave signal and the driving signal by taking the characteristic of the driving signal as the reference, and restoring the driven signal into measured data.
9. A passive wireless signal coherence judging transmission system as recited in claim 8, wherein said transceiver modulates the microwave driving signal and transmits it.
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