CN116095814B - High-precision synchronization method and system for backscatter communication to combat wake-up delay - Google Patents
High-precision synchronization method and system for backscatter communication to combat wake-up delayInfo
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- CN116095814B CN116095814B CN202310115096.5A CN202310115096A CN116095814B CN 116095814 B CN116095814 B CN 116095814B CN 202310115096 A CN202310115096 A CN 202310115096A CN 116095814 B CN116095814 B CN 116095814B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/001—Synchronization between nodes
- H04W56/0015—Synchronization between nodes one node acting as a reference for the others
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
- H04B5/70—Near-field transmission systems, e.g. inductive or capacitive transmission systems specially adapted for specific purposes
- H04B5/77—Near-field transmission systems, e.g. inductive or capacitive transmission systems specially adapted for specific purposes for interrogation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
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- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
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Abstract
本发明提供了一种对抗唤醒延迟的反向散射通信高精度同步方法及系统，包括：步骤S1：发射控制帧与标签同步，控制帧包含粗同步序列与细同步序列；步骤S2：标签唤醒模块利用粗同步序列进行粗同步，同步完成后唤醒标签同步模块；步骤S3：标签同步模块唤醒后利用细同步序列进行同步，与数据帧在时域上对齐。本发明通过对细同步序列进行精心设计，使标签可以对抗唤醒延迟，实现高精度同步；本发明标签仍具备超低功耗的工作特点，额外引入的同步模块大部分时间处于休眠状态，只在需要进行高精度同步时被唤醒处于工作状态。
The present invention provides a high-precision synchronization method and system for backscatter communications that combats wake-up delays, including: Step S1: transmitting a control frame to synchronize with a tag, the control frame comprising a coarse synchronization sequence and a fine synchronization sequence; Step S2: the tag wake-up module performs coarse synchronization using the coarse synchronization sequence, waking up the tag synchronization module after synchronization is complete; Step S3: after waking up, the tag synchronization module performs synchronization using the fine synchronization sequence, aligning the tag with the data frame in the time domain. By carefully designing the fine synchronization sequence, the present invention enables the tag to combat wake-up delays and achieve high-precision synchronization. The tags of the present invention also feature ultra-low power consumption, and the additional synchronization module remains dormant most of the time, waking up and operating only when high-precision synchronization is required.
Description
Technical Field
The invention relates to the field of communication, in particular to a high-precision synchronization method and a high-precision synchronization system for backscatter communication for resisting wake-up delay.
Background
Backscatter communications have been widely used in RIFD (radio frequency identification) systems, forming many large-scale commercial cases. The working principle is that a receiver sends a radio frequency excitation signal to activate a passive node, an electronic tag utilizes back scattering communication to modulate own information on the radio frequency signal, and a reader receives and demodulates a reflected signal of the passive electronic tag to realize information transmission. The existing backscatter communication system cannot realize multi-tag synchronous access.
Patent document CN109076014a (application number: CN 201780027114.7) discloses a method of synchronizing a label database in a packet-switched communication network, comprising the steps of establishing a communication path between a stateful path computation element (path computation element, PCE) and a path computation client (path computation client, PCC), modifying a label update message at the PCE to include a synchronization flag, and transmitting the label update message to the PCC. But the invention does not utilize coarse and fine synchronization sequences for higher precision synchronization.
Patent document CN102799839B (application number: CN 201110133835.0) discloses a method for synchronous wake-up communication of an active RFID system, after the system is powered on, an active RFID reader works in a receiving state, an active RFID electronic tag sends information to the reader, after the reader receives the information, a reply signal is sent to the electronic tag, and both parties start to enter synchronization with the time as a time starting point. A timing synchronous awakening method, a synchronous calibration process and a synchronous frequency hopping process can be added in the synchronous awakening process. According to the invention, the RFID electronic tag and the RFID card reader successfully communicate for the first time as the time synchronization signal, and the subsequent communication wakes up according to the set time, so that the synchronous wake-up of the RFID electronic tag and the RFID card reader in the sleep state is realized, and the power consumption is lower. But the invention does not eliminate the different wake-up delays between tags.
Disclosure of Invention
In view of the defects in the prior art, the invention aims to provide a high-precision synchronization method and system for backscatter communication for resisting wake-up delay.
The invention provides a backscattering communication high-precision synchronization method for resisting wake-up delay, which comprises the following steps:
step S1, transmitting a control frame and synchronizing with a tag, wherein the control frame comprises a coarse synchronizing sequence and a fine synchronizing sequence;
s2, the tag awakening module performs coarse synchronization by using a coarse synchronization sequence, and awakens the tag synchronizing module after synchronization is completed;
And step S3, after the label synchronization module wakes up, synchronizing with the data frame by using the fine synchronization sequence, and aligning with the data frame in the time domain.
Preferably, in said step S1:
s1.1, generating a bit sequence for identifying an order according to a preset synchronization frequency N;
S1.2, carrying out exclusive or exclusive or operation on the generated sequence identification sequence and a preset barker code according to the bits in sequence to generate a synchronous sequence;
step S1.3, splicing the generated synchronous sequence with a preset equal-length gap sequence to form a complete fine synchronous sequence;
And S1.4, adding the generated fine synchronization sequence into a control frame, and enabling a transmitter in the reflection communication system to realize synchronization with the tag by transmitting the control frame before transmitting the data frame.
Preferably, the step S1.1 includes that the high-precision synchronization times N are not limited, and the single sequence identification length is correspondingly
The step S1.2 comprises the steps that the preset barker code does not limit the length of the barker code;
the step S1.3 comprises the steps that the preset equal-length gap sequences separate two adjacent sequence identification symbols, and the two adjacent sequence identification symbols are not mutually influenced when the correlation coefficient is calculated;
The equal-length gap sequence comprises two design modes, wherein the first design mode is all 0 or all 1, and is suitable for a synchronous module with the decision threshold stability higher than a preset standard, and the second design mode is 0 and 1 alternately, and is suitable for a synchronous module with the decision threshold dynamically adjusted along with an environmental signal;
The step S1.4 comprises that the reflective communication system does not limit the number of tag nodes, and is single-node or multi-node, wherein the number of nodes in the multi-node reflective communication system is determined by the hardware characteristics of an analog circuit of hardware.
Preferably, in said step S3:
S3.1, the synchronous module of the label is awakened after delay, and starts to synchronize;
s3.2, the synchronization module demodulates the fine synchronization sequence by utilizing a decision circuit to realize analog-to-digital conversion;
s3.3, inputting the bit sequence obtained by analog-to-digital conversion into a plurality of barker code correlators in a digital circuit, performing exclusive OR or exclusive OR operation on a single correlator by using the barker code and the input sequence, and respectively obtaining two correlation results PC and NC by taking non-sum according to the bits and then summing according to the bits;
Step S3.4, PC and NC are respectively compared with a threshold value to obtain two binarization results P, N and P, N, when the or value of the two binarization results is 0, invalid bits are judged to be transmitted, when the or value of P, N is 1, the transmitted bits are judged to be equal to N or P, and when all the bits are judged to be valid, all the bits are spliced to obtain a single sequence identifier;
And S3.5, after the sequence identifier is obtained, the label is aligned with the control frame in the time domain, a timer in the synchronous module starts to count, the control frame is waited to be transmitted, and the label starts to modulate when the data frame arrives.
Preferably, the step S3.1 comprises that the wake-up delay generating factors comprise WuRx wake-up receiver and capacitation circuit;
The step S3.3 includes that the number of the barker code correlators depends on the bit number of a single sequence identifier, when the bit number is X, the bit sequence input into the correlators has X sections, the length of each section is equal to the length of the barker code, and the correlation results are calculated by the X barker code correlators in sequence;
When the fine synchronization sequence is generated by exclusive or, exclusive or operation, the correlator adopts exclusive or operation;
The step S3.4 comprises the steps that the threshold value is a constant value, the maximum Y of the threshold value of the Y-bit barker code is determined according to the length of the barker code and the actual situation.
The invention provides a backscatter communication high-precision synchronization system for resisting wake-up delay, which comprises:
the module M1 is used for transmitting a control frame and synchronizing a label, wherein the control frame comprises a coarse synchronizing sequence and a fine synchronizing sequence;
The module M2 is used for carrying out rough synchronization by the label awakening module by utilizing a rough synchronization sequence, and awakening the label synchronizing module after synchronization is completed;
and the module M3 is used for synchronizing with the data frame in a time domain after the label synchronization module wakes up.
Preferably, in said module M1:
A module M1.1, generating a bit sequence for identifying the sequence according to a preset synchronization frequency N;
A module M1.2 is used for carrying out exclusive OR or exclusive OR operation on the generated sequence identification sequence and a preset barker code in sequence according to the bits to generate a synchronous sequence;
The module M1.3 is used for splicing the generated synchronous sequence with a preset equal-length gap sequence to form a complete fine synchronous sequence;
The module M1.4 adds the generated fine synchronization sequence to a control frame by which a transmitter in the reflective communication system achieves synchronization with the tag prior to transmitting the data frame.
Preferably, the module M1.1 comprises the high-precision synchronization times N without limitation, and the single sequence identification length is correspondingly
The module M1.2 includes that the preset barker code does not limit the barker code length;
The module M1.3 comprises that the preset equal-length gap sequences separate two adjacent sequence identification symbols, and the two adjacent sequence identification symbols are not mutually influenced when the correlation coefficient is calculated;
The equal-length gap sequence comprises two design modes, wherein the first design mode is all 0 or all 1, and is suitable for a synchronous module with the decision threshold stability higher than a preset standard, and the second design mode is 0 and 1 alternately, and is suitable for a synchronous module with the decision threshold dynamically adjusted along with an environmental signal;
the module M1.4 comprises that the reflective communication system does not limit the number of tag nodes, and is single-node or multi-node, wherein the number of nodes in the multi-node reflective communication system is determined by the hardware characteristics of an analog circuit of hardware.
Preferably, in said module M3:
the module M3.1 is that the synchronous module of the label is awakened after delay and starts to synchronize;
The module M3.2 is used for demodulating the fine synchronization sequence by the synchronization module by utilizing a decision circuit to realize analog-to-digital conversion;
the bit sequence obtained by analog-to-digital conversion is input into a plurality of barker code correlators in a digital circuit, a single correlator utilizes the barker code to carry out exclusive or exclusive or operation with the input sequence, and the obtained result is subjected to bit summation and bit non-summation to obtain two correlation results PC and NC respectively;
PC, NC compare with threshold value separately, get two binarization result P, N, P, N or value is 0, judge the transmission is invalid bit, P, N or value is 1, judge the bit of transmission is equal to N or P, when all bits judge valid, splice all bits and get the single order identification symbol;
And a module M3.5, after the sequence identifier is obtained, the label is aligned with the control frame in the time domain, a timer in the synchronous module starts to count time, the control frame is waited to be transmitted, and the label starts to modulate when the data frame arrives.
Preferably, the module M3.1 comprises that the wake-up delay generating factor comprises WuRx wake-up receiver and capacitation circuit;
the module M3.3 comprises that the number of the barker code correlators depends on the bit number of a single sequence identifier, when the bit number is X, the bit sequence input into the correlators has X sections, the length of each section is equal to the length of the barker code, and the correlation results are calculated by the X barker code correlators in sequence;
When the fine synchronization sequence is generated by exclusive or, exclusive or operation, the correlator adopts exclusive or operation;
the module M3.4 comprises that the threshold value is a constant value, and the maximum Y of the threshold value of the Y-bit barker code is determined according to the length of the barker code and the actual situation.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention can make the label resist the wake-up delay by carefully designing the fine synchronization sequence, thereby realizing high-precision synchronization;
2. The tag still has the working characteristic of ultra-low power consumption, and the additionally introduced synchronization module is in a dormant state for most of the time, and is only awakened when high-precision synchronization is needed to be carried out, and is in a working state;
3. The carefully designed fine synchronization sequence has good robustness, can effectively eliminate different wake-up delays among the tags, and is suitable for a reflective communication system requiring multi-tag synchronous access.
Drawings
Other features, objects and advantages of the present invention will become more apparent upon reading of the detailed description of non-limiting embodiments, given with reference to the accompanying drawings in which:
FIG. 1 is a schematic diagram of a multi-tag synchronous access process in a multi-tag reflective communication system;
FIG. 2 is a schematic diagram of a process for generating a fine synchronization sequence based on a barker code;
fig. 3 is a schematic diagram of a synchronization process of the tag synchronization module.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications could be made by those skilled in the art without departing from the inventive concept. These are all within the scope of the present invention.
Example 1:
Aiming at the problem that the existing backscatter communication system can not realize multi-tag synchronous access, the invention provides a backscatter communication high-precision synchronization technology for resisting wake-up delay.
The invention relates to the technical field of low-power consumption communication, time domain synchronization and wireless communication, and provides a high-precision synchronization technology of backscatter communication for resisting wake-up delay, comprising the following steps that S1, a transmitter in a reflection communication system realizes synchronization with a tag by transmitting a control frame before transmitting a data frame, wherein the control frame comprises a coarse synchronization sequence and a barker code-based fine synchronization sequence capable of resisting wake-up delay; and S2, the label awakening module performs coarse synchronization by using a coarse synchronization sequence in a mode of envelope detection and the like, and wakes up the label fine synchronization module after synchronization is completed, and S3, the label synchronizing module is awakened after a certain delay, and can still perform higher-precision synchronization by using the fine synchronization sequence and is aligned with the data frame in the time domain. In a multi-tag reflective communication system, synchronization between tags is critical, and this process can be accomplished by synchronizing all tags to the transmitter. The tag is used as an Internet of things node and has the working characteristic of ultra-low power consumption, and the synchronous process is also characterized in that the nW-level wake-up module is used for monitoring an environment signal to keep ultra-low power consumption running, and after a coarse synchronous sequence is detected, the mu W-level synchronous module is waken up, and a certain delay is brought to the wake-up process, so that the subsequent fine synchronous process is influenced.
According to the invention, as shown in fig. 1-3, a high-precision synchronization method for backscatter communication against wake-up delay comprises the following steps:
step S1, transmitting a control frame and synchronizing with a tag, wherein the control frame comprises a coarse synchronizing sequence and a fine synchronizing sequence;
Specifically, in the step S1:
s1.1, generating a bit sequence for identifying an order according to a preset synchronization frequency N;
S1.2, carrying out exclusive or exclusive or operation on the generated sequence identification sequence and a preset barker code according to the bits in sequence to generate a synchronous sequence;
step S1.3, splicing the generated synchronous sequence with a preset equal-length gap sequence to form a complete fine synchronous sequence;
And S1.4, adding the generated fine synchronization sequence into a control frame, and enabling a transmitter in the reflection communication system to realize synchronization with the tag by transmitting the control frame before transmitting the data frame.
Specifically, the step S1.1 includes that the high-precision synchronization times N are not limited, and the single sequence identification length is correspondingly
The step S1.2 comprises the steps that the preset barker code does not limit the length of the barker code;
the step S1.3 comprises the steps that the preset equal-length gap sequences separate two adjacent sequence identification symbols, and the two adjacent sequence identification symbols are not mutually influenced when the correlation coefficient is calculated;
The equal-length gap sequence comprises two design modes, wherein the first design mode is all 0 or all 1, and is suitable for a synchronous module with the decision threshold stability higher than a preset standard, and the second design mode is 0 and 1 alternately, and is suitable for a synchronous module with the decision threshold dynamically adjusted along with an environmental signal;
The step S1.4 comprises that the reflective communication system does not limit the number of tag nodes, and is single-node or multi-node, wherein the number of nodes in the multi-node reflective communication system is determined by the hardware characteristics of an analog circuit of hardware.
S2, the tag awakening module performs coarse synchronization by using a coarse synchronization sequence, and awakens the tag synchronizing module after synchronization is completed;
And step S3, after the label synchronization module wakes up, synchronizing with the data frame by using the fine synchronization sequence, and aligning with the data frame in the time domain.
Specifically, in the step S3:
S3.1, the synchronous module of the label is awakened after delay, and starts to synchronize;
s3.2, the synchronization module demodulates the fine synchronization sequence by utilizing a decision circuit to realize analog-to-digital conversion;
s3.3, inputting the bit sequence obtained by analog-to-digital conversion into a plurality of barker code correlators in a digital circuit, performing exclusive OR or exclusive OR operation on a single correlator by using the barker code and the input sequence, and respectively obtaining two correlation results PC and NC by taking non-sum according to the bits and then summing according to the bits;
Step S3.4, PC and NC are respectively compared with a threshold value to obtain two binarization results P, N and P, N, when the or value of the two binarization results is 0, invalid bits are judged to be transmitted, when the or value of P, N is 1, the transmitted bits are judged to be equal to N or P, and when all the bits are judged to be valid, all the bits are spliced to obtain a single sequence identifier;
And S3.5, after the sequence identifier is obtained, the label is aligned with the control frame in the time domain, a timer in the synchronous module starts to count, the control frame is waited to be transmitted, and the label starts to modulate when the data frame arrives.
Specifically, the step S3.1 comprises the steps that the wake-up delay generating factors comprise WuRx wake-up receivers and an enabling circuit;
The step S3.3 includes that the number of the barker code correlators depends on the bit number of a single sequence identifier, when the bit number is X, the bit sequence input into the correlators has X sections, the length of each section is equal to the length of the barker code, and the correlation results are calculated by the X barker code correlators in sequence;
When the fine synchronization sequence is generated by exclusive or, exclusive or operation, the correlator adopts exclusive or operation;
The step S3.4 comprises the steps that the threshold value is a constant value, the maximum Y of the threshold value of the Y-bit barker code is determined according to the length of the barker code and the actual situation.
Example 2:
Example 2 is a preferable example of example 1 to more specifically explain the present invention.
The present invention also provides a backscatter communication high-precision synchronization system against a wakeup delay, which can be implemented by executing the flow steps of the backscatter communication high-precision synchronization method against a wakeup delay, that is, a person skilled in the art can understand the backscatter communication high-precision synchronization method against a wakeup delay as a preferred embodiment of the backscatter communication high-precision synchronization system against a wakeup delay.
The invention provides a backscatter communication high-precision synchronization system for resisting wake-up delay, which comprises:
the module M1 is used for transmitting a control frame and synchronizing a label, wherein the control frame comprises a coarse synchronizing sequence and a fine synchronizing sequence;
Specifically, in the module M1:
A module M1.1, generating a bit sequence for identifying the sequence according to a preset synchronization frequency N;
A module M1.2 is used for carrying out exclusive OR or exclusive OR operation on the generated sequence identification sequence and a preset barker code in sequence according to the bits to generate a synchronous sequence;
The module M1.3 is used for splicing the generated synchronous sequence with a preset equal-length gap sequence to form a complete fine synchronous sequence;
The module M1.4 adds the generated fine synchronization sequence to a control frame by which a transmitter in the reflective communication system achieves synchronization with the tag prior to transmitting the data frame.
In particular, the module M1.1 comprises the high-precision synchronization times N without limitation, the single sequence identification length is correspondingly
The module M1.2 includes that the preset barker code does not limit the barker code length;
The module M1.3 comprises that the preset equal-length gap sequences separate two adjacent sequence identification symbols, and the two adjacent sequence identification symbols are not mutually influenced when the correlation coefficient is calculated;
The equal-length gap sequence comprises two design modes, wherein the first design mode is all 0 or all 1, and is suitable for a synchronous module with the decision threshold stability higher than a preset standard, and the second design mode is 0 and 1 alternately, and is suitable for a synchronous module with the decision threshold dynamically adjusted along with an environmental signal;
the module M1.4 comprises that the reflective communication system does not limit the number of tag nodes, and is single-node or multi-node, wherein the number of nodes in the multi-node reflective communication system is determined by the hardware characteristics of an analog circuit of hardware.
The module M2 is used for carrying out rough synchronization by the label awakening module by utilizing a rough synchronization sequence, and awakening the label synchronizing module after synchronization is completed;
and the module M3 is used for synchronizing with the data frame in a time domain after the label synchronization module wakes up.
Specifically, in the module M3:
the module M3.1 is that the synchronous module of the label is awakened after delay and starts to synchronize;
The module M3.2 is used for demodulating the fine synchronization sequence by the synchronization module by utilizing a decision circuit to realize analog-to-digital conversion;
the bit sequence obtained by analog-to-digital conversion is input into a plurality of barker code correlators in a digital circuit, a single correlator utilizes the barker code to carry out exclusive or exclusive or operation with the input sequence, and the obtained result is subjected to bit summation and bit non-summation to obtain two correlation results PC and NC respectively;
PC, NC compare with threshold value separately, get two binarization result P, N, P, N or value is 0, judge the transmission is invalid bit, P, N or value is 1, judge the bit of transmission is equal to N or P, when all bits judge valid, splice all bits and get the single order identification symbol;
And a module M3.5, after the sequence identifier is obtained, the label is aligned with the control frame in the time domain, a timer in the synchronous module starts to count time, the control frame is waited to be transmitted, and the label starts to modulate when the data frame arrives.
Specifically, the module M3.1 comprises that the wake-up delay generating factors comprise WuRx wake-up receiver and capacitation circuit;
the module M3.3 comprises that the number of the barker code correlators depends on the bit number of a single sequence identifier, when the bit number is X, the bit sequence input into the correlators has X sections, the length of each section is equal to the length of the barker code, and the correlation results are calculated by the X barker code correlators in sequence;
When the fine synchronization sequence is generated by exclusive or, exclusive or operation, the correlator adopts exclusive or operation;
the module M3.4 comprises that the threshold value is a constant value, and the maximum Y of the threshold value of the Y-bit barker code is determined according to the length of the barker code and the actual situation.
Example 3:
Example 3 is a preferable example of example 1 to more specifically explain the present invention.
According to the invention, a high-precision synchronization technology for backscatter communication against wake-up delay is provided, comprising:
Step S1, before a transmitter in a reflection communication system transmits a data frame, the transmitter realizes synchronization with a tag by transmitting a control frame, wherein the control frame comprises a coarse synchronization sequence and a fine synchronization sequence which can resist wake-up delay and is based on a barker code;
S2, performing coarse synchronization by using a coarse synchronization sequence through an nW-level wake-up module of the tag in a mode of envelope detection and the like, and waking up a mu W-level synchronization module of the tag after synchronization is completed;
step S3, the synchronous module of the label is awakened after a certain delay, and still can use the fine synchronous sequence to carry out higher-precision synchronization and align with the data frame in the time domain.
Preferably, the step S1 includes:
Step S1.1, generating a bit sequence for identifying an order according to a preset high-precision synchronization number N, wherein when n=8, the generated order identification sequence is 000,001, a.the.a., 111;
step S1.2, carrying out exclusive OR or exclusive OR operation on the generated sequence identification sequence and a preset barker code in sequence according to the bits to generate a synchronous sequence, wherein if the exclusive OR of the 001 bit barker code (11100010010) and the 11 bit barker code generates a synchronous sequence 11100010010 11100010010 00011101101 corresponding to the exclusive OR;
Step S1.3: splicing the generated synchronous sequence with a preset equal-length gap sequence to form a complete fine synchronous sequence, for example, when the preset gap sequence is a 33-bit all 0 sequence, 001 corresponds to a complete synchronization sequence of 1110001001011100010010 00011101101 00..0 (33 bits 0), i.e., each order corresponds to a 66-bit fine synchronization sequence;
And S1.4, adding the generated fine synchronization sequence into a control frame, and enabling a transmitter in the reflection communication system to realize synchronization with the tag by transmitting the control frame before transmitting the data frame.
Preferably, the step S1.1 comprises generating a bit sequence for identifying the order according to a preset high-precision synchronization number N;
The high-precision synchronization times N are not limited, and the length of the single sequence identifier is correspondingly as follows
Preferably, the step S1.2 comprises the steps of performing exclusive OR or exclusive OR operation on the generated sequence identification sequence and a preset barker code in sequence according to the bits to generate a synchronous sequence;
the preset barker code does not limit the barker code length, and comprises 13-bit barker codes, 11-bit barker codes and the like.
Preferably, the step S1.3 comprises splicing the generated synchronization sequence with a preset equal-length gap sequence to form a complete fine synchronization sequence;
The preset equal-length gap sequence is used for separating two adjacent sequence identification symbols, and the two adjacent sequence identification symbols are not mutually influenced in calculating the correlation coefficient. The equal length gap sequence comprises two designs, the first design is all 0 or all 1, and the second design is 0,1 alternately, i.e. 1010..10 or 0101..01. The first design mode is suitable for a synchronous module with a basically unchanged decision threshold, the gap sequence of all 0 s or all 1s does not influence the decision threshold of a decision circuit, and the fine synchronous sequence can be normally demodulated. The second design mode is suitable for a synchronous module with the decision threshold dynamically adjusted along with the environmental signal, and the gap sequence of all 0 or all 1 can obviously change the decision threshold of the decision circuit, which can seriously affect the demodulation of the fine synchronous sequence, so that the gap sequence of 0 and 1 alternation is designed for the synchronous module.
Preferably, the step S1.4 comprises adding the generated fine synchronization sequence to a control frame by which a transmitter in the reflective communication system achieves synchronization with the tag prior to transmitting the data frame;
the reflection communication system does not limit the number of the tag nodes, and can be single nodes or multiple nodes, wherein the number of the nodes in the multiple-node reflection communication system can reach hundreds of levels, and the number of the nodes specifically supported is determined by the hardware characteristics of an analog circuit of hardware, including oscillator precision, impedance network reflection coefficient precision, multiple access protocol and the like.
Preferably, the step S3 includes:
s3.1, a synchronous module of the tag is awakened after a certain delay, and starts to synchronize;
s3.2, the synchronization module demodulates the fine synchronization sequence by utilizing a decision circuit to realize analog-to-digital conversion;
s3.3, inputting the bit sequence obtained by analog-to-digital conversion into a plurality of barker code correlators in a digital circuit, performing exclusive OR or exclusive OR operation on a single correlator by using the barker code and the input sequence, and respectively obtaining two correlation results PC and NC by taking non-sum according to the bits and then summing according to the bits;
Step S3.4, PC and NC are respectively compared with a threshold value to obtain two binarization results P, N and P, N, when the OR value is 0, invalid bits are judged to be transmitted, when the OR value of P, N is 1, the transmitted bits are judged to be equal to N (same or related) or P (exclusive or related), and when all the bits are judged to be valid, all the bits are spliced to obtain a single sequence identification symbol;
and S3.5, after the sequence identifier is obtained, the label is aligned with the control frame in the time domain, a timer in the synchronous module starts to count, the control frame is waited to be transmitted, and the label starts to modulate when the data frame arrives.
Preferably, the step S3.1 comprises that the synchronous module of the tag is awakened after a certain delay to start synchronization;
the wake-up delay may come from WuRx to wake-up the receiver or from other factors that may cause a wake-up delay, such as the enabling circuit.
Preferably, the step S3.3 includes inputting a bit sequence obtained by analog-to-digital conversion into a plurality of barker code correlators in a digital circuit, performing exclusive OR or exclusive OR operation on a single correlator and the input sequence by using the barker code, and respectively obtaining two correlation results PC and NC by taking non-sum according to bits and then summing according to bits;
The number of the barker code correlators depends on the number of bits of a single sequence identifier, if the number of bits is 3, the bit sequence input into the correlators has 3 segments, each segment has the length equal to the length of the barker code, and the correlation results are calculated by the 3 barker code correlators in sequence. When the fine synchronization sequence is generated using an exclusive or/exclusive or operation, the correlator uses an exclusive or/exclusive or operation.
Preferably, the step S3.4 includes comparing PC and NC with threshold values respectively, when the sum of two binarization results P, N and P, N is 0, determining that an invalid bit is transmitted, when the sum of P, N is 1, determining that the transmitted bit is equal to N (same or related) or P (exclusive or related), and when all the determined bits are valid, concatenating all the bits to obtain a single sequence identifier;
The threshold is a constant value, and is determined according to the length of the barker code and the actual situation, for example, the maximum threshold of the 11-bit barker code can be obtained as 11.
Example 4:
Example 4 is a preferable example of example 1 to more specifically explain the present invention.
According to the invention, a high-precision synchronization technology for backscatter communication against wake-up delay is provided, comprising:
Step S1, before a transmitter in a reflection communication system transmits a data frame, the transmitter realizes synchronization with a tag by transmitting a control frame, wherein the control frame comprises a coarse synchronization sequence and a fine synchronization sequence which can resist wake-up delay and is based on a barker code;
S2, performing coarse synchronization by using a coarse synchronization sequence through an nW-level wake-up module of the tag in a mode of envelope detection and the like, and waking up a mu W-level synchronization module of the tag after synchronization is completed;
step S3, the synchronous module of the label is awakened after a certain delay, and still can use the fine synchronous sequence to carry out higher-precision synchronization and align with the data frame in the time domain.
Specifically, the step S1 includes:
the reflection communication system sets the high-precision synchronization times to be 8, and the generated sequence identification sequence is 000,001, the number of the first and the second is 111;
S1.2, performing exclusive OR operation on the generated sequence identification sequence and 11-bit barker code in sequence according to the bits to generate a synchronous sequence, wherein the synchronous sequence corresponds to 11100010010 11100010010 00011101101 of a sequence identification symbol 001;
Step S1.3: splicing the generated synchronization sequence with the equal-length all 0-gap sequence to form a complete fine synchronization sequence, a complete synchronization sequence corresponding to 001 is 11100010010 11100010010 00011101101 00..0 (33 bits 0), each order corresponds to a 66-bit fine synchronization sequence;
Step S1.4. Adding the generated fine synchronization sequence with total length 528 to a control frame by which a transmitter in the reflective communication system achieves synchronization with the tag before transmitting the data frame.
Specifically, the step S3 includes:
s3.1, a synchronous module of the tag is awakened after a certain delay, and starts to synchronize;
s3.2, the synchronization module demodulates the fine synchronization sequence by utilizing a decision circuit to realize analog-to-digital conversion;
Step S3.3, inputting the bit sequence obtained by analog-to-digital conversion into 3 barker code correlators in a digital circuit, performing exclusive OR operation on a single correlator by using the barker code and the input sequence, and respectively obtaining two correlation results PC and NC by taking non-sum according to bits and then summing according to bits;
Step S3.4, PC and NC are respectively compared with a threshold value to obtain two binarization results P, N and P, N, when the OR value is 0, invalid bits are judged to be transmitted, when the OR value of P, N is 1, the transmitted bits are judged to be equal to N, and when all the bits are judged to be valid, all the bits are spliced to obtain a single sequence identifier;
and S3.5, after the sequence identifier is obtained, the label is aligned with the control frame in the time domain, a timer in the synchronous module starts to count, the control frame is waited to be transmitted, and the label starts to modulate when the data frame arrives.
More specifically, as shown in fig. 1, all tags in the reflective communication system are aligned with the control frame in the time domain through the steps described above, and then, the respective timers are used to count the time, wait for the transmission of the control frame to finish, and synchronously access the data frame when the data frame arrives, and start modulating the data.
Example 5:
example 5 is a preferable example of example 1 to more specifically explain the present invention.
According to the invention, a high-precision synchronization technology for backscatter communication against wake-up delay is provided, comprising:
Step S1, before a transmitter in a reflection communication system transmits a data frame, the transmitter realizes synchronization with a tag by transmitting a control frame, wherein the control frame comprises a coarse synchronization sequence and a fine synchronization sequence which can resist wake-up delay and is based on a barker code;
S2, performing coarse synchronization by using a coarse synchronization sequence through an nW-level wake-up module of the tag in a mode of envelope detection and the like, and waking up a mu W-level synchronization module of the tag after synchronization is completed;
step S3, the synchronous module of the label is awakened after a certain delay, and still can use the fine synchronous sequence to carry out higher-precision synchronization and align with the data frame in the time domain.
Specifically, the step S1 includes:
The method comprises the following steps of S1.1, setting high-precision synchronization times to be 6 by a reflection communication system, and generating a sequence identification sequence of 000,001, wherein the number of times of synchronization is 101;
S1.2, carrying out exclusive OR operation on the generated sequence identification sequence and the 11-bit barker code in sequence to generate a synchronous sequence, wherein the synchronous sequence corresponds to 00011101101 00011101101 11100010010 of a sequence identification symbol 001;
step S1.3, splicing the generated synchronous sequences with alternate gap sequences with equal length of 0 and 1 to form complete fine synchronous sequences, wherein if the complete synchronous sequence corresponding to 001 is 00011101101 00011101101 11100010010 0101..0 (33 bits alternate), each sequence corresponds to 66 bits of fine synchronous sequences;
Step S1.4. Adding the generated fine synchronization sequence with total length 396 to a control frame by which a transmitter in the reflective communication system achieves synchronization with the tag prior to transmitting the data frame.
Specifically, the step S3 includes:
s3.1, a synchronous module of the tag is awakened after a certain delay, and starts to synchronize;
s3.2, the synchronization module demodulates the fine synchronization sequence by utilizing a decision circuit to realize analog-to-digital conversion;
Step S3.3, inputting the bit sequence obtained by analog-to-digital conversion into 3 barker code correlators in a digital circuit, performing exclusive OR operation on a single correlator by using the barker code and the input sequence, and respectively obtaining two correlation results PC and NC by taking non-sum according to the bit and then summing according to the bit;
Step S3.4, PC and NC are respectively compared with a threshold value to obtain two binarization results P, N and P, N, when the OR value is 0, invalid bits are judged to be transmitted, when the OR value of P, N is 1, the transmitted bits are judged to be equal to N, and when all the bits are judged to be valid, all the bits are spliced to obtain a single sequence identifier;
and S3.5, after the sequence identifier is obtained, the label is aligned with the control frame in the time domain, a timer in the synchronous module starts to count, the control frame is waited to be transmitted, and the label starts to modulate when the data frame arrives.
Those skilled in the art will appreciate that the systems, apparatus, and their respective modules provided herein may be implemented entirely by logic programming of method steps such that the systems, apparatus, and their respective modules are implemented as logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers, etc., in addition to the systems, apparatus, and their respective modules being implemented as pure computer readable program code. Therefore, the system, the device and the respective modules thereof provided by the invention can be regarded as a hardware component, and the modules for realizing various programs included therein can be regarded as a structure in the hardware component, and the modules for realizing various functions can be regarded as a structure in the hardware component as well as a software program for realizing the method.
The foregoing describes specific embodiments of the present application. It is to be understood that the application is not limited to the particular embodiments described above, and that various changes or modifications may be made by those skilled in the art within the scope of the appended claims without affecting the spirit of the application. The embodiments of the application and the features of the embodiments may be combined with each other arbitrarily without conflict.
Claims (6)
1. A method for high precision synchronization of backscatter communications against wakeup delays, comprising:
step S1, transmitting a control frame and synchronizing with a tag, wherein the control frame comprises a coarse synchronizing sequence and a fine synchronizing sequence;
s2, the tag awakening module performs coarse synchronization by using a coarse synchronization sequence, and awakens the tag synchronizing module after synchronization is completed;
S3, after the label synchronization module wakes up, synchronizing with the data frame by using a fine synchronization sequence, and aligning with the data frame in the time domain;
in the step S1:
s1.1, generating a bit sequence for identifying an order according to a preset synchronization frequency N;
S1.2, carrying out exclusive or exclusive or operation on the generated sequence identification sequence and a preset barker code according to the bits in sequence to generate a synchronous sequence;
step S1.3, splicing the generated synchronous sequence with a preset equal-length gap sequence to form a complete fine synchronous sequence;
step S1.4, adding the generated fine synchronization sequence into a control frame, and enabling a transmitter in a reflection communication system to realize synchronization with a tag by transmitting the control frame before transmitting a data frame;
in the step S3:
S3.1, the synchronous module of the label is awakened after delay, and starts to synchronize;
s3.2, the synchronization module demodulates the fine synchronization sequence by utilizing a decision circuit to realize analog-to-digital conversion;
s3.3, inputting the bit sequence obtained by analog-to-digital conversion into a plurality of barker code correlators in a digital circuit, performing exclusive OR or exclusive OR operation on a single correlator by using the barker code and the input sequence, and respectively obtaining two correlation results PC and NC by taking non-sum according to the bits and then summing according to the bits;
Step S3.4, PC and NC are respectively compared with a threshold value to obtain two binarization results P, N and P, N, when the or value of the two binarization results is 0, invalid bits are judged to be transmitted, when the or value of P, N is 1, the transmitted bits are judged to be equal to N or P, and when all the bits are judged to be valid, all the bits are spliced to obtain a single sequence identifier;
And S3.5, after the sequence identifier is obtained, the label is aligned with the control frame in the time domain, a timer in the synchronous module starts to count, the control frame is waited to be transmitted, and the label starts to modulate when the data frame arrives.
2. The backscatter communications high precision synchronization method to combat wakeup delay of claim 1, wherein:
The step S1.1 comprises that the high-precision synchronization times N are not limited, and the single sequence identification length is correspondingly equal to
The step S1.2 comprises the steps that the preset barker code does not limit the length of the barker code;
the step S1.3 comprises the steps that the preset equal-length gap sequences separate two adjacent sequence identification symbols, and the two adjacent sequence identification symbols are not mutually influenced when the correlation coefficient is calculated;
The equal-length gap sequence comprises two design modes, wherein the first design mode is all 0 or all 1, and is suitable for a synchronous module with the decision threshold stability higher than a preset standard, and the second design mode is 0 and 1 alternately, and is suitable for a synchronous module with the decision threshold dynamically adjusted along with an environmental signal;
The step S1.4 comprises that the reflective communication system does not limit the number of tag nodes, and is single-node or multi-node, wherein the number of nodes in the multi-node reflective communication system is determined by the hardware characteristics of an analog circuit of hardware.
3. The backscatter communications high precision synchronization method to combat wakeup delay of claim 1, wherein:
The step S3.1 comprises the steps that the wake-up delay generating factors comprise WuRx wake-up receivers and an enabling circuit;
The step S3.3 includes that the number of the barker code correlators depends on the bit number of a single sequence identifier, when the bit number is X, the bit sequence input into the correlators has X sections, the length of each section is equal to the length of the barker code, and the correlation results are calculated by the X barker code correlators in sequence;
When the fine synchronization sequence is generated by exclusive or, exclusive or operation, the correlator adopts exclusive or operation;
The step S3.4 comprises the steps that the threshold value is a constant value, the maximum Y of the threshold value of the Y-bit barker code is determined according to the length of the barker code and the actual situation.
4. A backscatter communications high precision synchronization system that counters wake-up delay, comprising:
the module M1 is used for transmitting a control frame and synchronizing a label, wherein the control frame comprises a coarse synchronizing sequence and a fine synchronizing sequence;
The module M2 is used for carrying out rough synchronization by the label awakening module by utilizing a rough synchronization sequence, and awakening the label synchronizing module after synchronization is completed;
the module M3 is used for synchronizing with the data frame in a time domain after the label synchronization module wakes up;
in the module M1:
A module M1.1, generating a bit sequence for identifying the sequence according to a preset synchronization frequency N;
A module M1.2 is used for carrying out exclusive OR or exclusive OR operation on the generated sequence identification sequence and a preset barker code in sequence according to the bits to generate a synchronous sequence;
The module M1.3 is used for splicing the generated synchronous sequence with a preset equal-length gap sequence to form a complete fine synchronous sequence;
a module M1.4, adding the generated fine synchronization sequence into a control frame, and enabling a transmitter in the reflection communication system to realize synchronization with a tag by transmitting the control frame before transmitting a data frame;
in the module M3:
the module M3.1 is that the synchronous module of the label is awakened after delay and starts to synchronize;
The module M3.2 is used for demodulating the fine synchronization sequence by the synchronization module by utilizing a decision circuit to realize analog-to-digital conversion;
the bit sequence obtained by analog-to-digital conversion is input into a plurality of barker code correlators in a digital circuit, a single correlator utilizes the barker code to carry out exclusive or exclusive or operation with the input sequence, and the obtained result is subjected to bit summation and bit non-summation to obtain two correlation results PC and NC respectively;
PC, NC compare with threshold value separately, get two binarization result P, N, P, N or value is 0, judge the transmission is invalid bit, P, N or value is 1, judge the bit of transmission is equal to N or P, when all bits judge valid, splice all bits and get the single order identification symbol;
And a module M3.5, after the sequence identifier is obtained, the label is aligned with the control frame in the time domain, a timer in the synchronous module starts to count time, the control frame is waited to be transmitted, and the label starts to modulate when the data frame arrives.
5. The backscatter communications high precision synchronization system of claim 4, wherein the wake-up delay is counter-acted, wherein:
The module M1.1 comprises the high-precision synchronization times N without limitation, and the single sequence identification length is correspondingly
The module M1.2 includes that the preset barker code does not limit the barker code length;
The module M1.3 comprises that the preset equal-length gap sequences separate two adjacent sequence identification symbols, and the two adjacent sequence identification symbols are not mutually influenced when the correlation coefficient is calculated;
The equal-length gap sequence comprises two design modes, wherein the first design mode is all 0 or all 1, and is suitable for a synchronous module with the decision threshold stability higher than a preset standard, and the second design mode is 0 and 1 alternately, and is suitable for a synchronous module with the decision threshold dynamically adjusted along with an environmental signal;
the module M1.4 comprises that the reflective communication system does not limit the number of tag nodes, and is single-node or multi-node, wherein the number of nodes in the multi-node reflective communication system is determined by the hardware characteristics of an analog circuit of hardware.
6. The backscatter communications high precision synchronization system of claim 4, wherein the wake-up delay is counter-acted, wherein:
the module M3.1 comprises that the wake-up delay generating factors comprise WuRx wake-up receiver and capacitation circuit;
the module M3.3 comprises that the number of the barker code correlators depends on the bit number of a single sequence identifier, when the bit number is X, the bit sequence input into the correlators has X sections, the length of each section is equal to the length of the barker code, and the correlation results are calculated by the X barker code correlators in sequence;
When the fine synchronization sequence is generated by exclusive or, exclusive or operation, the correlator adopts exclusive or operation;
the module M3.4 comprises that the threshold value is a constant value, and the maximum Y of the threshold value of the Y-bit barker code is determined according to the length of the barker code and the actual situation.
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