CN115173886B - Echo cancellation system applied to long-distance UHF RFID reader-writer - Google Patents
Echo cancellation system applied to long-distance UHF RFID reader-writer Download PDFInfo
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- 230000005540 biological transmission Effects 0.000 claims description 19
- 230000015572 biosynthetic process Effects 0.000 claims description 18
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
- H04B1/50—Circuits using different frequencies for the two directions of communication
- H04B1/52—Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa
- H04B1/525—Hybrid arrangements, i.e. arrangements for transition from single-path two-direction transmission to single-direction transmission on each of two paths or vice versa with means for reducing leakage of transmitter signal into the receiver
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
- G06K7/10297—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves arrangements for handling protocols designed for non-contact record carriers such as RFIDs NFCs, e.g. ISO/IEC 14443 and 18092
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
- G06K7/10316—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves using at least one antenna particularly designed for interrogating the wireless record carriers
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- H04B5/77—
Abstract
The invention provides an echo cancellation system applied to a long-distance UHF RFID reader-writer, which comprises the following components: the receiving module is used for receiving a data transmitting signal on a transmitting link from the remote UHF RFID reader-writer, receiving a leakage signal transmitted from the antenna and receiving a data receiving signal on a receiving link from the remote UHF RFID reader-writer; the signal processing module is used for processing the data transmitting signal based on the leakage signal and generating a cancellation signal; the signal cancellation module is used for carrying out cancellation processing on the data receiving signal based on the cancellation signal to obtain a target data receiving signal; the receiving sensitivity of the obtained target data receiving signal on the long-distance UHF RFID reader-writer is ensured, and the communication of the long-distance UHF RFID reader-writer is better realized.
Description
Technical Field
The invention relates to the technical field of long-distance radio frequency identification, in particular to an echo cancellation system applied to a long-distance UHF RFID reader-writer.
Background
The ultra-high Frequency RFID (Radio Frequency Identification) is a non-contact Radio Frequency Identification technology working at 840 MHz-960 MHz. The RFID reader-writer of the UHF frequency band transmits and receives radio frequency signals through an antenna to realize automatic identification of the label.
The remote tag identification is generally realized by an RFID reader/writer in the UHF band. In order to realize long-distance tag identification, the UHF frequency band RFID reader-writer can enable the tag to be coupled to enough energy even in a long distance by continuously increasing the transmitting power of the power amplifier, and a returned response signal can be transmitted to the RFID reader-writer. In the receiving state of the reader/writer, the Power Amplifier (PA) is still required to transmit a continuous carrier signal high enough to power the rf tag.
The traditional echo cancellation method is to subtract an echo signal from a received signal to realize echo cancellation, but because the transmission and the reception of the RFID reader of the UHF band share the antenna, a transmitted continuous carrier signal can leak to a receiving end through a coupler, the RFID reader-writer is just positioned in the middle of a frequency band for receiving signals, and a radio frequency filter cannot be used for filtering echo signals to influence the receiving sensitivity, so that the reading distance of the RFID reader-writer in a UHF frequency band is influenced.
Disclosure of Invention
The invention provides an echo cancellation system applied to a long-distance UHF RFID reader-writer, which ensures the receiving sensitivity of an obtained target data receiving signal on the long-distance UHF RFID reader-writer and better realizes the communication of the long-distance UHF RFID reader-writer.
An echo cancellation system applied to a long-distance UHF RFID reader-writer comprises:
the receiving module is used for receiving a data transmitting signal from a transmitting link of the remote UHF RFID reader-writer, receiving a leakage signal transmitted by the antenna and receiving a data receiving signal from a receiving link of the remote UHF RFID reader-writer;
the signal processing module is used for processing the data transmitting signal based on the leakage signal to generate a cancellation signal;
and the signal cancellation module is used for carrying out cancellation processing on the data receiving signal based on the cancellation signal to obtain a target data receiving signal.
Preferably, the receiving module includes:
the interface unit is used for respectively establishing communication connection with the transmitting link, the antenna and the receiving link;
a receiving unit for receiving high frequency signals from the transmitting chain, the antenna and the receiving chain based on the communication connection;
and the processing unit is used for carrying out signal distortion processing on the acquired high-frequency signal through a distortion eliminator and a demodulator and outputting the data transmitting signal, the leakage signal and the data receiving signal.
Preferably, the interface unit includes:
the transmitting interface unit is used for identifying a first identifier of the transmitting link and establishing communication connection between the transmitting interface and the transmitting link according to the first identifier;
the leakage interface unit is used for identifying a second identifier of the antenna and establishing communication connection between the leakage interface and the antenna according to the second identifier;
and the receiving interface unit is used for identifying the third identifier of the receiving link and establishing the communication connection between the receiving interface and the receiving link according to the third identifier.
Preferably, the signal processing module includes:
the characteristic extraction unit is used for extracting the signal characteristics of the leakage signal to obtain first signal characteristics, and extracting the signal characteristics of the data transmitting signal to obtain second signal characteristics;
a feature analysis unit, configured to extract a first threshold signal in the leakage signal and a second threshold signal in the data transmission signal based on the first signal feature and the second signal feature;
a signal processing unit for processing the first and second threshold signals, and acquiring a cancellation signal meeting the requirement from the echo reference signal.
Preferably, the feature extraction unit includes:
a sampling unit for sampling the leakage signal and the data transmission signal to obtain a discrete leakage signal and a discrete transmission signal, carrying out Fourier transform on the discrete leakage signal and the discrete transmitting signal to obtain a frequency domain leakage signal and a frequency domain transmitting signal;
and the extraction unit is used for extracting a peak value, an optimal order and a kurtosis value of the frequency domain leakage signal and the frequency domain transmission signal, taking the first peak value, the first optimal order and the first kurtosis value of the frequency domain leakage signal obtained through extraction as first signal characteristics, and taking the second peak value, the second optimal order and the second kurtosis value of the frequency domain transmission signal obtained through extraction as second signal characteristics.
Preferably, the feature analysis unit includes:
a first selection unit for selecting, based on the second signal characteristic, extracting a second threshold signal of which a second peak value, a second optimal order and a second kurtosis value meet the requirement of a preset threshold from the data transmitting signal;
a relationship determination unit for determining a relationship between the first signal characteristic and the second signal characteristic, acquiring corresponding relations among a second peak value, a second optimal order and a second kurtosis value as well as a first peak value, a first optimal order and a first kurtosis value;
a second selecting unit for selecting, based on the correspondence, and selecting a first threshold signal meeting a preset corresponding relation from the leakage signals.
Preferably, the signal processing unit is configured to, for example, the method comprises the following steps:
a configuration relationship determining unit, configured to obtain a first link configuration of the transmitting link and a second link configuration of the receiving link, and establish a configuration corresponding relationship between the first link configuration and the second link configuration according to a configuration attribute;
a configuration comparison unit, configured to compare configuration information of the first link configuration and the second link configuration according to the configuration correspondence, so as to obtain a differential configuration sequence;
the difference determining unit is used for determining the difference characteristic brought by each element in the difference configuration sequence according to the difference of the processing signals on the link brought by the difference of the configuration information, and obtaining the overall difference characteristic of the processing signals between the transmitting link and the receiving link based on the difference characteristic;
a signal determining unit, configured to determine an influence feature on a signal based on the overall difference feature, and perform signal transformation on the second threshold signal based on the influence feature to obtain an echo signal;
the frequency mixing unit is used for determining a frequency mixing frequency based on the receiving frequency range of the remote UHF RFID reader-writer, and performing frequency mixing processing on the echo signal and the first threshold signal to obtain a frequency mixing signal;
an interference signal determining unit, configured to compare the difference between the mixing signal and a standard mixing signal to obtain a direct current component difference, determine an extraction rule of the mixing signal for a signal component based on the direct current component difference, and perform signal extraction on the mixing signal according to the extraction rule to obtain an interference signal;
and the cancellation signal determining unit is used for selecting a target reference signal which is equal to the amplitude of the interference signal and opposite to the phase of the interference signal from the echo reference signal as the cancellation signal.
Preferably, the signal cancellation module includes:
the image superposition unit is used for acquiring a first signal image of the data receiving signal and a second signal image of the offset signal, and superposing the first signal image and the second signal image based on any starting point to obtain a superposed signal image;
the error determining unit is used for extracting the characteristics of the superposed signal image to obtain superposed characteristics, inputting the superposed characteristics into a time delay prediction model and outputting a time delay error amount;
a node determining unit, configured to perform alignment processing on the data receiving signal and the cancellation signal based on the delay error amount to obtain a cancellation signal node of the data receiving signal and the cancellation signal;
a signal synthesis unit, configured to set a first time and a second time when the data receiving signal and the cancellation signal enter the receiving link, respectively, based on the cancellation signal node, and perform synthesis processing on the data receiving signal and the cancellation signal by using a preset objective function according to the first time and the second time to obtain a first synthesis signal;
a weight determining unit, configured to determine a signal processor of the receiving link, determine a power influence factor for a passing signal according to a parameter of the signal processor, and determine a synthesis weight of the signal processor in a signal synthesis process according to a mapping relationship between the power influence factor and the synthesis weight;
a signal weighting unit, configured to perform weighting processing when the first synthesized signal passes through the corresponding signal processor according to the sequence of passing through the signal processor based on the synthesized weight, and input a weighted signal obtained through the weighting processing to a next signal processor for performing the weighting processing until the weighted signal is output from a last signal processor, so as to obtain a second addition signal;
the denoising unit is used for calculating whether the signal-to-noise ratio of the second addition signal is greater than a preset signal-to-noise ratio;
if so, determining the second addition signal as a target data receiving signal;
otherwise, determining a threshold filtering range based on the signal-to-noise ratio, filtering the second addition signal according to the threshold filtering range to obtain a third addition signal, and determining the third addition signal as a target data receiving signal.
Preferably, the method further comprises the following steps: the test module is used for testing the receiving sensitivity of the target data receiving signal;
the test module comprises:
a signal acquiring unit, configured to acquire an uncancelled echo signal in the receiving link, perform signal detection on the target data receiving signal, and extract an uncancelled signal in the target data receiving signal;
the signal detection unit is used for inputting the uncancelled echo signal and the non-cancelable signal into a power detection model to obtain an average power oscillogram of the uncancelled echo signal and an average power oscillogram of the non-cancelable signal;
the first judgment unit is used for determining the average power trend amplitude of the uncancelled echo signal based on the uncancelled echo signal average power oscillogram and judging whether the average power trend amplitude meets the preset trend amplitude or not;
if not, determining that the receiving sensitivity of the target data receiving signal does not meet the sensitivity requirement;
if so, determining a cancellation coefficient of the target data receiving signal according to the echo signal average power oscillogram and the non-cancellation signal average power oscillogram;
a second judging unit, configured to judge whether the cancellation coefficient is greater than a preset cancellation coefficient;
if not, determining that the receiving sensitivity of the target data receiving signal does not meet the sensitivity requirement;
if the difference is larger than the preset value, inputting the target data receiving signal into a signal response model to obtain a target data receiving signal response waveform, and inputting a standard signal obtained by subtracting the offset interference signal from the target data receiving signal into the signal response model to obtain a standard signal response waveform;
a third judging unit, configured to obtain a waveform difference between the target data receiving signal response waveform and a standard signal response waveform, and judge whether the waveform difference is smaller than a preset waveform difference;
if so, determining that the receiving sensitivity of the target data receiving signal meets the sensitivity requirement;
otherwise, determining that the receiving sensitivity of the target data receiving signal does not meet the sensitivity requirement.
Preferably, in the first determining unit, determining, according to the non-cancelled echo signal average power oscillogram and the non-cancelled signal average power oscillogram, a cancellation coefficient of the target data receiving signal is specifically:
the energy determining unit is used for calculating and obtaining the energy of the uncancelled echo signal and the energy of the uncancelled echo signal based on the average power oscillogram of the uncancelled echo signal and the average power oscillogram of the uncancelled echo signal;
and the coefficient determining unit is used for calculating the ratio of the energy of the uncancelled echo signal to the energy of the uncancelled echo signal, and subtracting the ratio from 1 to obtain a cancellation coefficient.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
fig. 1 is a structural diagram of an echo cancellation system applied to a long-distance UHF RFID reader in an embodiment of the present invention;
FIG. 2 is a block diagram of the receiving module according to an embodiment of the present invention;
fig. 3 is a block diagram of a signal processing module not described in the embodiment of the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
Example 1
The embodiment of the invention provides an echo cancellation system applied to a long-distance UHF RFID reader-writer, as shown in FIG. 1, comprising:
the receiving module is used for receiving a data transmitting signal on a transmitting link from the remote UHF RFID reader-writer, receiving a leakage signal transmitted from the antenna and receiving a data receiving signal on a receiving link from the remote UHF RFID reader-writer;
the signal processing module is used for processing the data transmitting signal based on the leakage signal and generating a cancellation signal;
and the signal cancellation module is used for carrying out cancellation processing on the data receiving signal based on the cancellation signal to obtain a target data receiving signal.
In this embodiment, the leakage signal is a part of the data transmission signal from the transmission link that leaks onto the reception link and cannot be eliminated by the filter, and the signal frequency is just within the frequency band of the data reception signal, thereby causing interference to the data reception signal on the reception link.
In this embodiment, the signal processing module operates according to a principle of processing the data transmitting signal according to a leakage signal to generate a cancellation signal capable of canceling the data receiving signal.
In this embodiment, the cancellation processing on the data receiving signal is specifically to process the data receiving signal by using the cancellation signal to obtain a target data receiving signal.
The beneficial effect of above-mentioned design is: the acquired data transmitting signals and the leakage signals are analyzed and processed through the signal processing module to obtain cancellation signals which can cancel the data receiving signals, the cancellation signals and the data receiving signals are subjected to signal cancellation processing through the signal cancellation module to obtain target data receiving signals, interference of the leakage signals is eliminated through the obtained target data receiving signals, the receiving sensitivity of the obtained target data receiving signals on a long-distance UHF RFID reader-writer is ensured, and communication of the long-distance UHF RFID reader-writer is better achieved.
Example 2
Based on embodiment 1, an embodiment of the present invention provides an echo cancellation system applied to a long-distance UHF RFID reader, where as shown in fig. 2, the receiving module includes:
the interface unit is used for establishing communication connection with the transmitting link, the antenna and the receiving link respectively;
a receiving unit for receiving high frequency signals from the transmit chain, antenna and receive chain based on the communication connection;
and the processing unit is used for carrying out signal distortion processing on the acquired high-frequency signal through a distortion eliminator and a demodulator and outputting the data transmitting signal, the leakage signal and the data receiving signal.
In this embodiment, linear and nonlinear distortions of a high frequency signal can be cancelled by signal distortion processing by a distortion canceller and a demodulator.
The beneficial effect of above-mentioned design is: the communication connection is established through the interface unit, the acquisition of signals is realized, the linear and nonlinear distortion of high-frequency signals is eliminated through the processing unit, and the accuracy of obtaining data transmitting signals, leakage signals and data receiving signals is ensured.
Example 3
Based on embodiment 2, an embodiment of the present invention provides an echo cancellation system applied to a long-distance UHF RFID reader, where the interface unit includes:
the transmitting interface unit is used for identifying a first identifier of the transmitting link and establishing communication connection between the transmitting interface and the transmitting link according to the first identifier;
the leakage interface unit is used for identifying a second identifier of the antenna and establishing communication connection between the leakage interface and the antenna according to the second identifier;
and the receiving interface unit is used for identifying the third identifier of the receiving link and establishing the communication connection between the receiving interface and the receiving link according to the third identifier.
The beneficial effect of above-mentioned design is: by establishing different signal interfaces for the transmitting link, the receiving link and the antenna, a classification basis is provided for the subsequent processing of different received signals.
Example 4
Based on embodiment 1, an embodiment of the present invention provides an echo cancellation system applied to a long-distance UHF RFID reader, as shown in fig. 3, where the signal processing module includes:
the characteristic extraction unit is used for extracting the signal characteristics of the leakage signal to obtain first signal characteristics, and extracting the signal characteristics of the data transmitting signal to obtain second signal characteristics;
a feature analysis unit, configured to extract a first threshold signal in the leakage signal and a second threshold signal in the data transmission signal based on the first signal feature and the second signal feature;
and the signal processing unit is used for acquiring a cancellation signal meeting the requirement from the echo reference signal based on the first threshold signal and the second threshold signal.
In this embodiment, the first threshold signal and the second threshold signal are signals that satisfy the threshold requirement and are obtained according to the first signal characteristic and the second signal characteristic.
In this embodiment, the cancellation signal is a signal that cancels a partial signal of the data reception signal.
In this embodiment, the reference echo signal is a plurality of signals with different phase amplitudes.
The beneficial effect of above-mentioned design is: the signal processing module is used for analyzing and processing the leakage signal and the data transmitting signal to obtain a cancellation signal which can generate cancellation for partial signals of the data receiving signal, and a basis is provided for realizing echo cancellation.
Example 5
Based on embodiment 4, an embodiment of the present invention provides an echo cancellation system applied to a long-distance UHF RFID reader, where the feature extraction unit includes:
the sampling unit is used for sampling the leakage signal and the data transmitting signal to obtain a discrete leakage signal and a discrete transmitting signal, and carrying out Fourier transform on the discrete leakage signal and the discrete transmitting signal to obtain a frequency domain leakage signal and a frequency domain transmitting signal;
and the extraction unit is used for extracting a peak value, an optimal order and a kurtosis value of the frequency domain leakage signal and the frequency domain transmission signal, taking the first peak value, the first optimal order and the first kurtosis value of the frequency domain leakage signal obtained by extraction as first signal characteristics, and taking the second peak value, the second optimal order and the second kurtosis value of the frequency domain transmission signal obtained by extraction as second signal characteristics.
In this embodiment, the leakage signal and the data transmission signal are sampled and fourier transformed, so that signal characteristics can be better obtained to characterize the leakage signal and the data transmission signal.
In this embodiment, the values and the value relationships of the peak values, the optimal orders, and the kurtosis values of the frequency domain leakage signal and the frequency domain transmission signal directly affect the situation that the leakage signal generates the direct current component and the interference on the data transmission signal.
The beneficial effect of above-mentioned design is: by sampling and Fourier transforming the leakage signal and the data transmitting signal, the characteristics of the leakage signal and the data transmitting signal are better represented, and an accurate offset signal is obtained to provide a basis.
Example 6
Based on embodiment 4, an embodiment of the present invention provides an echo cancellation system applied to a long-distance UHF RFID reader, where the feature analysis unit includes:
a first selecting unit, configured to extract, from the data transmitting signal, a second threshold signal in which a second peak value, a second optimal order, and a second kurtosis value satisfy a preset threshold requirement based on the second signal characteristic;
a relationship determining unit, configured to obtain a correspondence between a second peak, a second best order, and a second kurtosis value and a first peak, a first best order, and a first kurtosis value based on the first signal feature and the second signal feature;
and the second selection unit is used for selecting a first threshold signal meeting a preset corresponding relation from the leakage signals based on the corresponding relation.
In this embodiment, the preset threshold requirement is set according to the situation of the data transmission signal, for example, when the second peak value, the second optimal order and the second kurtosis value are within a certain threshold range, the probability of interference is greater, so the certain threshold range is set as the preset threshold requirement.
In this embodiment, the corresponding relationship is a corresponding relationship between the first peak, the first best order and the first kurtosis value and the second peak, the second best order and the second kurtosis value respectively in the same time period.
In this embodiment, the predetermined correspondence relationship is a requirement for a first peak, a first optimum order and a first kurtosis value when the threshold range of the first threshold signal has a large interference influence on the second threshold signal under the second threshold signal.
The beneficial effect of above-mentioned design is: and selecting a second threshold signal of the first threshold signal from the leakage signal and the data transmitting signal according to the value and the corresponding relation of the first signal characteristic and the second signal characteristic, so as to provide an effective and accurate data basis for determining the offset signal.
Example 7
On the basis of real-time 4, the embodiment of the invention provides an echo cancellation system applied to a long-distance UHF RFID reader-writer, and the signal processing unit comprises:
a configuration relationship determining unit, configured to obtain a first link configuration of the transmitting link and a second link configuration of the receiving link, and establish a configuration corresponding relationship between the first link configuration and the second link configuration according to a configuration attribute;
a configuration comparison unit, configured to compare configuration information of the first link configuration and the second link configuration according to the configuration correspondence, so as to obtain a differential configuration sequence;
the difference determining unit is used for determining the difference characteristic brought by each element in the difference configuration sequence according to the difference of the processing signals on the link brought by the difference of the configuration information, and obtaining the overall difference characteristic of the processing signals between the transmitting link and the receiving link based on the difference characteristic;
a signal determining unit, configured to determine an influence feature on a signal based on the overall difference feature, and perform signal transformation on the second threshold signal based on the influence feature to obtain an echo signal;
the frequency mixing unit is used for determining frequency mixing frequency based on the receiving frequency range of the long-distance UHF RFID reader-writer, and performing frequency mixing processing on the echo signal and the first threshold signal to obtain a frequency mixing signal;
an interference signal determining unit, configured to compare the difference between the mixing signal and a standard mixing signal to obtain a direct current component difference, determine an extraction rule of the mixing signal for a signal component based on the direct current component difference, and perform signal extraction on the mixing signal according to the extraction rule to obtain an interference signal;
and the cancellation signal determining unit is used for selecting a target reference signal which has the same amplitude and opposite phase with the interference signal from the echo reference signal as the cancellation signal.
In this embodiment, the link configurations of the transmitting link and the receiving link include, for example, an amplifier, a coupler, and a synthesizer, which are used for the difference of parameters of the amplifier, the coupler, and the synthesizer, so that the data transmitting signal on the transmitting link generates an echo, and the signal after passing through the receiving link is determined by the link configuration of the receiving link, and therefore, the echo signal generated by the data transmitting signal is finally predicted by determining the configuration corresponding relationship between the first link configuration and the second link configuration, thereby ensuring the accuracy of the predicted echo signal, and providing a basis for selecting an accurate cancellation signal.
In this embodiment, the sequence of difference configurations is, for example, a sequence of parameter differences of amplifiers, couplers and synthesizers, the corresponding influencing features having different consequences on the output signal due to the parameter differences.
In this embodiment, the magnitude of the dc component difference directly affects the extraction rule of the mixing-dependent signal, for example, the filtering rule of the extraction rule determined according to the dc component difference.
In this embodiment, the standard mixing signal is predetermined according to the characteristics of the transmit chain and the receive chain.
The beneficial effect of above-mentioned design is: the first threshold signal and the second threshold signal are analyzed and processed according to the link configuration of the transmitting link and the receiving link, the receiving frequency range of the long-distance UHF RFID reader-writer and the extraction rule of the signal components, so that the accuracy of the offset signal is ensured from multiple aspects, and a foundation is provided for echo offset.
Example 8
Based on embodiment 1, an embodiment of the present invention provides an echo cancellation system applied to a long-distance UHF RFID reader, where the signal cancellation module includes:
the image superposition unit is used for acquiring a first signal image of the data receiving signal and a second signal image of the offset signal, and superposing the first signal image and the second signal image based on any starting point to obtain a superposed signal image;
the error determining unit is used for extracting the characteristics of the superposed signal image to obtain superposed characteristics, inputting the superposed characteristics into a time delay prediction model and outputting a time delay error amount;
a node determining unit, configured to perform alignment processing on the data receiving signal and the cancellation signal based on the delay error amount to obtain a cancellation signal node of the data receiving signal and the cancellation signal;
a signal synthesis unit, configured to set a first time and a second time when the data receiving signal and the cancellation signal enter the receiving link, respectively, based on the cancellation signal node, and perform synthesis processing on the data receiving signal and the cancellation signal by using a preset objective function according to the first time and the second time to obtain a first synthesis signal;
a weight determining unit, configured to determine a signal processor of the receiving link, determine a power influence factor for a passing signal according to a parameter of the signal processor, and determine a synthesis weight of the signal processor in a signal synthesis process according to a mapping relationship between the power influence factor and the synthesis weight;
a signal weighting unit, configured to perform weighting processing when the first synthesized signal passes through a corresponding signal processor according to the sequence of passing through the signal processor based on the synthesized weight, and input a weighted signal obtained through the weighting processing to a next signal processor for performing the weighting processing until the weighted signal is output from a last signal processor, so as to obtain a second addition signal;
the denoising unit is used for calculating whether the signal-to-noise ratio of the second addition signal is greater than a preset signal-to-noise ratio;
if so, determining the second addition signal as a target data receiving signal;
otherwise, determining a threshold filtering range based on the signal-to-noise ratio, filtering the second addition signal according to the threshold filtering range to obtain a third addition signal, and determining the third addition signal as a target data receiving signal.
In this embodiment, the signal processor includes, for example, an amplifier, a coupler, a filter, and the like.
The beneficial effect of above-mentioned design is: by acquiring the time delay error amount, an accurate offset signal node is determined, so that the first time and the second time of the data receiving signal and the offset signal entering the receiving link are determined, the time matching of the data receiving signal and the offset signal in the first synthetic signal is ensured, the accuracy of acquiring the target data receiving signal is ensured, and the receiving sensitivity of the receiving link to the target data receiving signal is ensured; the power influence factor of the passing signal is determined according to the parameters of the signal processor to set a synthesis weight, the first synthesis signal is weighted, the signal power of the second weighted signal is ensured to be obtained, and the receiving sensitivity of a receiving link to a target data receiving signal is ensured in terms of power value; whether the second addition signal is subjected to filtering and denoising processing is determined according to the signal-to-noise ratio of the second addition signal, so that the minimum interference on the target data receiving signal is ensured, and the receiving sensitivity of a receiving link on the target data receiving signal is ensured.
Example 9
Based on embodiment 1, an embodiment of the present invention provides an echo cancellation system applied to a long-distance UHF RFID reader, further including: the test module is used for testing the receiving sensitivity of the target data receiving signal;
the test module comprises:
a signal acquiring unit, configured to acquire an uncancelled echo signal in the receiving link, perform signal detection on the target data receiving signal, and extract an uncancelled signal in the target data receiving signal;
the signal detection unit is used for inputting the uncancelled echo signal and the non-cancelable signal into a power detection model to obtain an average power oscillogram of the uncancelled echo signal and an average power oscillogram of the non-cancelable signal;
the first judgment unit is used for determining the average power trend amplitude of the uncancelled echo signal based on the uncancelled echo signal average power oscillogram and judging whether the average power trend amplitude meets the preset trend amplitude or not;
if not, determining that the receiving sensitivity of the target data receiving signal does not meet the sensitivity requirement;
if so, determining a cancellation coefficient of the target data receiving signal according to the echo signal average power oscillogram and the non-cancellation signal average power oscillogram;
a second judging unit, configured to judge whether the cancellation coefficient is greater than a preset cancellation coefficient;
if not, determining that the receiving sensitivity of the target data receiving signal does not meet the sensitivity requirement;
if the difference is larger than the preset value, inputting the target data receiving signal into a signal response model to obtain a target data receiving signal response waveform, and inputting a standard signal obtained by subtracting the offset interference signal from the target data receiving signal into the signal response model to obtain a standard signal response waveform;
a third judging unit, configured to obtain a waveform difference between the target data receiving signal response waveform and a standard signal response waveform, and judge whether the waveform difference is smaller than a preset waveform difference;
if yes, determining that the receiving sensitivity of the target data receiving signal meets the sensitivity requirement;
otherwise, determining that the receiving sensitivity of the target data receiving signal does not meet the sensitivity requirement.
In this embodiment, the non-cancelable signals in the target data reception signal include non-cancelable interference signals and other non-interference-generating signals.
In this embodiment, the average power trend amplitude should gradually decrease according to a preset amplitude until it tends to be stable.
The beneficial effect of above-mentioned design is: whether the receiving sensitivity of the target data receiving signal meets the sensitivity requirement or not is determined by comparing and analyzing the signal average power and the signal response of the non-cancelled signal in the non-cancelled echo signal and the target data receiving signal in the receiving link, and the obtained target data receiving signal is tested by the testing module, so that the cancellation performance of the echo cancellation system is determined, the receiving sensitivity is not better ensured, the reading distance of an RFID reader-writer in a UHF frequency band is ensured, and a testing basis is provided.
Example 10
Based on embodiment 9, an embodiment of the present invention provides an echo cancellation system applied to a long-distance UHF RFID reader, where in the first determination unit, according to the average power waveform diagram of the un-cancelled echo signal and the average power waveform diagram of the un-cancelled echo signal, determining a cancellation coefficient of the target data receiving signal specifically is:
the energy determining unit is used for calculating and obtaining the energy of the uncancelled echo signal and the energy of the uncancelled echo signal based on the average power oscillogram of the uncancelled echo signal and the average power oscillogram of the uncancelled echo signal;
and the coefficient determining unit is used for calculating the ratio of the energy of the uncancelled echo signal to the energy of the uncancelled echo signal, and subtracting the ratio from 1 to obtain a cancellation coefficient.
The beneficial effect of above-mentioned design is: the cancellation coefficient is determined according to the ratio of the energy of the non-cancelled echo signal to the energy of the non-cancelled echo signal, and the cancellation coefficient is analyzed from the energy angle, so that the cancellation effect of the echo cancellation effect of the target data receiving signal can be well reflected by the cancellation coefficient.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (9)
1. An echo cancellation system applied to a long-distance UHF RFID reader-writer is characterized by comprising:
the receiving module is used for receiving a data transmitting signal from a transmitting link of the remote UHF RFID reader-writer, receiving a leakage signal transmitted by the antenna and receiving a data receiving signal from a receiving link of the remote UHF RFID reader-writer;
the signal processing module is used for processing the data transmitting signal based on the leakage signal and generating a cancellation signal;
the signal cancellation module is used for carrying out cancellation processing on the data receiving signal based on the cancellation signal to obtain a target data receiving signal;
the signal cancellation module includes:
the image superposition unit is used for acquiring a first signal image of the data receiving signal and a second signal image of the offset signal, and superposing the first signal image and the second signal image based on any starting point to obtain a superposed signal image;
the error determining unit is used for extracting the characteristics of the superposed signal image to obtain superposed characteristics, inputting the superposed characteristics into a time delay prediction model and outputting a time delay error amount;
a node determining unit, configured to perform alignment processing on the data receiving signal and the cancellation signal based on the delay error amount to obtain a cancellation signal node of the data receiving signal and the cancellation signal;
the signal synthesis unit is used for respectively setting a first time and a second time for the data receiving signal and the cancellation signal to enter the receiving link based on the cancellation signal node, and synthesizing the data receiving signal and the cancellation signal by using a preset objective function according to the first time and the second time to obtain a first synthesized signal;
a weight determining unit, configured to determine a signal processor of the receiving link, determine a power influence factor for a passing signal according to a parameter of the signal processor, and determine a synthesis weight of the signal processor in a signal synthesis process according to a mapping relationship between the power influence factor and the synthesis weight;
a signal weighting unit, configured to perform weighting processing when the first synthesized signal passes through the corresponding signal processor according to the sequence of passing through the signal processor based on the synthesized weight, and input a weighted signal obtained through the weighting processing to a next signal processor for performing the weighting processing until the weighted signal is output from a last signal processor, so as to obtain a second addition signal;
the denoising unit is used for calculating whether the signal-to-noise ratio of the second addition signal is greater than a preset signal-to-noise ratio;
if yes, determining the second addition signal as a target data receiving signal;
otherwise, determining a threshold filtering range based on the signal-to-noise ratio, filtering the second addition signal according to the threshold filtering range to obtain a third addition signal, and determining the third addition signal as a target data receiving signal.
2. The echo cancellation system for long-distance UHF RFID readers/writers according to claim 1, wherein said receiving module comprises:
the interface unit is used for establishing communication connection with the transmitting link, the antenna and the receiving link respectively;
a receiving unit for receiving high frequency signals from the transmit chain, antenna and receive chain based on the communication connection;
and the processing unit is used for carrying out signal distortion processing on the acquired high-frequency signal through a distortion eliminator and a demodulator and outputting the data transmitting signal, the leakage signal and the data receiving signal.
3. The echo cancellation system for long-distance UHF RFID readers/writers according to claim 2, wherein said interface unit comprises:
the transmitting interface unit is used for identifying a first identifier of the transmitting link and establishing communication connection between the transmitting interface and the transmitting link according to the first identifier;
the leakage interface unit is used for identifying a second identifier of the antenna and establishing communication connection between the leakage interface and the antenna according to the second identifier;
and the receiving interface unit is used for identifying the third identifier of the receiving link and establishing the communication connection between the receiving interface and the receiving link according to the third identifier.
4. The echo cancellation system for long-distance UHF RFID readers/writers according to claim 1, wherein said signal processing module comprises:
the characteristic extraction unit is used for extracting the signal characteristics of the leakage signal to obtain first signal characteristics, and extracting the signal characteristics of the data transmitting signal to obtain second signal characteristics;
a feature analysis unit, configured to extract a first threshold signal in the leakage signal and a second threshold signal in the data transmission signal based on the first signal feature and the second signal feature;
and the signal processing unit is used for acquiring a cancellation signal meeting the requirement from the echo reference signal based on the first threshold signal and the second threshold signal.
5. The echo cancellation system for the long-distance UHF RFID reader/writer according to claim 4, wherein the feature extraction unit comprises:
the sampling unit is used for sampling the leakage signal and the data transmitting signal to obtain a discrete leakage signal and a discrete transmitting signal, and carrying out Fourier transform on the discrete leakage signal and the discrete transmitting signal to obtain a frequency domain leakage signal and a frequency domain transmitting signal;
and the extraction unit is used for extracting a peak value, an optimal order and a kurtosis value of the frequency domain leakage signal and the frequency domain transmission signal, taking the first peak value, the first optimal order and the first kurtosis value of the frequency domain leakage signal obtained by extraction as first signal characteristics, and taking the second peak value, the second optimal order and the second kurtosis value of the frequency domain transmission signal obtained by extraction as second signal characteristics.
6. The echo cancellation system for the long-distance UHF RFID reader/writer according to claim 4, wherein the characteristic analysis unit comprises:
a first selecting unit, configured to extract, from the data transmitting signal, a second threshold signal in which a second peak value, a second optimal order, and a second kurtosis value satisfy a preset threshold requirement based on the second signal characteristic;
a relationship determining unit, configured to obtain a correspondence between a second peak, a second best order, and a second kurtosis value and a first peak, a first best order, and a first kurtosis value based on the first signal feature and the second signal feature;
and the second selection unit is used for selecting a first threshold signal meeting a preset corresponding relation from the leakage signals based on the corresponding relation.
7. The echo cancellation system for long-distance UHF RFID readers/writers according to claim 4, wherein said signal processing unit comprises:
a configuration relationship determining unit, configured to obtain a first link configuration of the transmitting link and a second link configuration of the receiving link, and establish a configuration corresponding relationship between the first link configuration and the second link configuration according to a configuration attribute;
a configuration comparison unit, configured to compare configuration information of the first link configuration and the second link configuration according to the configuration correspondence, so as to obtain a differential configuration sequence;
the difference determining unit is used for determining the difference characteristic brought by each element in the difference configuration sequence according to the difference of the processing signals on the link brought by the difference of the configuration information, and obtaining the overall difference characteristic of the processing signals between the transmitting link and the receiving link based on the difference characteristic;
a signal determining unit, configured to determine an influence feature on a signal based on the overall difference feature, and perform signal transformation on the second threshold signal based on the influence feature to obtain an echo signal;
the frequency mixing unit is used for determining frequency mixing frequency based on the receiving frequency range of the long-distance UHF RFID reader-writer, and performing frequency mixing processing on the echo signal and the first threshold signal to obtain a frequency mixing signal;
an interference signal determining unit, configured to compare the difference between the mixing signal and a standard mixing signal to obtain a direct current component difference, determine an extraction rule of the mixing signal for a signal component based on the direct current component difference, and perform signal extraction on the mixing signal according to the extraction rule to obtain an interference signal;
and the cancellation signal determining unit is used for selecting a target reference signal which is equal to the amplitude of the interference signal and opposite to the phase of the interference signal from the echo reference signal as the cancellation signal.
8. The echo cancellation system for long-distance UHF RFID readers/writers according to claim 1, further comprising: the test module is used for testing the receiving sensitivity of the target data receiving signal;
the test module comprises:
the signal acquisition unit is used for acquiring an uncancelled echo signal in the receiving link, carrying out signal detection on the target data receiving signal and extracting an uncancelled signal in the target data receiving signal;
the signal detection unit is used for inputting the uncancelled echo signal and the non-cancelable signal into a power detection model to obtain an average power oscillogram of the uncancelled echo signal and an average power oscillogram of the non-cancelable signal;
the first judgment unit is used for determining the average power trend amplitude of the uncancelled echo signal based on the uncancelled echo signal average power oscillogram and judging whether the average power trend amplitude meets the preset trend amplitude or not;
if not, determining that the receiving sensitivity of the target data receiving signal does not meet the sensitivity requirement;
if yes, determining a cancellation coefficient of the target data receiving signal according to the echo signal average power oscillogram and a non-cancellation signal average power oscillogram;
a second judging unit, configured to judge whether the cancellation coefficient is greater than a preset cancellation coefficient;
if not, determining that the receiving sensitivity of the target data receiving signal does not meet the sensitivity requirement;
if the difference is larger than the preset value, inputting the target data receiving signal into a signal response model to obtain a target data receiving signal response waveform, and inputting a standard signal obtained by subtracting the offset interference signal from the target data receiving signal into the signal response model to obtain a standard signal response waveform;
a third judging unit, configured to obtain a waveform difference between the target data receiving signal response waveform and a standard signal response waveform, and judge whether the waveform difference is smaller than a preset waveform difference;
if yes, determining that the receiving sensitivity of the target data receiving signal meets the sensitivity requirement;
otherwise, determining that the receiving sensitivity of the target data receiving signal does not meet the sensitivity requirement.
9. The echo cancellation system for long-distance UHF RFID readers/writers according to claim 8, wherein in the first determining unit, according to the average power waveform diagram of the un-cancelled echo signal and the average power waveform diagram of the un-cancelled echo signal, determining the cancellation coefficient of the target data receiving signal specifically is:
the energy determining unit is used for calculating and obtaining the energy of the uncancelled echo signal and the energy of the uncancelled echo signal based on the average power oscillogram of the uncancelled echo signal and the average power oscillogram of the uncancelled echo signal;
and the coefficient determining unit is used for calculating the ratio of the energy of the non-cancellation echo signal to the energy of the non-cancellation echo signal and subtracting the ratio from 1 to obtain a cancellation coefficient.
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