CN115618898B - Method and device for detecting RFID (radio frequency identification) tag - Google Patents
Method and device for detecting RFID (radio frequency identification) tag Download PDFInfo
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- 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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- G06K19/0723—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
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Abstract
The invention discloses a method and a device for detecting RFID labels, wherein a certain RFID host computer obtains the code domain distribution of a plurality of RFID labels through wireless detection and feeds back and adjusts channel time slot parameters corresponding to RFID label codes, and the method comprises the following steps: sending a synchronous excitation signal containing a channel code domain identifier in a synchronous channel to enable the RFID tag to obtain time synchronization, and sending a code clock pulse signal in a specified tag channel time slot by code time conversion; performing time code distribution detection on the code clock pulse signal sent by the RFID tag to obtain code domain distribution of different tag response channels through time code conversion; adjusting the channel code domain identification according to the code domain distribution feedback, and updating and sending a corresponding synchronous excitation signal; and in different tag channel time slots, group reading and receiving the tag data frame sent by the RFID tag. The invention quickly detects the code domain distribution in the preposed time slot, feeds back and adjusts the channel time slot parameter, and improves the group reading efficiency of the RFID label.
Description
Technical Field
The invention relates to the technical field of wireless communication and edge intelligence of the Internet of things, mainly relates to signal time sequence, data efficiency and flow mechanism of an RFID wireless communication data transceiving protocol layer, and particularly relates to a method and a device for detecting an RFID label.
Background
Radio Frequency Identification (RFID) is one of the important technical means for short-range wireless communication. With the continuous development of the technology and the application of the internet of things, the RFID group reading technology has been widely applied.
The related technical standards of the RFID include international standards (e.g., defined by ISO and IEC standards), national standards (defined by the ministry of industry and informatization and the national standards administration committee), and industrial standards (e.g., the EPC standard defined by international and national industry organizations, such as international association of goods and codes (EAN) and united states Uniform Code Committee (UCC), for object identification). The related art of RFID mainly relates to: RFID radio channels and modulation schemes, RFID air interface communication protocol specifications, and RFID industry application coding specifications (e.g., logistics, animals, goods, and assets).
The existing related technical standard of the RFID mainly solves the problems of compatibility and interoperability between different manufacturers of equipment. However, for the group reading technology of the RFID tag, especially when the number of target objects facing the RFID tag is large, there are still large problems and optimization improvement spaces in the efficiency of group reading transient communication data, the group reading success rate, and the reliability.
Compared with other short-distance wireless communication modes, the passive or active RFID group reading technology mainly needs to solve the problem of transient communication data efficiency in the group reading process, so that transient channel resources must be more effectively utilized; and the method is not like other wireless communication modes, consumes more wireless channel resources to establish stable protocol handshake or communication connection so as to improve the subsequent data communication efficiency.
Because group reading communication needs to be completed within a transient time, the RFID host (reader, reader/writer) cannot allocate a channel time slot for tag response data transmission to each RFID cluster (tag) in an asynchronous manner, resulting in high uncertainty of the tag response channel time slot in the group reading process. Therefore, one of the core problems of the RFID group reading technology is how to more effectively utilize the wireless channel resources while avoiding collision of RFID tag response data. In the existing RFID group reading technical standard, the method for avoiding collision of RFID tag response data mainly comprises the following steps:
1) Random response: the RFID host does not need to allocate channel time slots to the RFID labels, and the communication protocol is simple; however, when the number of RFID tags is large, the transient response data collision probability is high, and the channel resource utilization efficiency is very low.
2) Synchronizing time slots: the RFID host needs to allocate a synchronous channel time slot to the RFID label, and the RFID label responds in the specified synchronous channel time slot; according to the method, under the condition that the number and the code domain characteristics of the RFID are known, the RFID host allocates the tag channel time slot through a command, and the utilization efficiency of wireless channel resources can be effectively improved.
3) Grouping excitation: the channel is distributed according to the group code or the code domain interval, and the method has the advantages that the label response data collision between different code domains can be avoided; but still can not avoid the collision of the label response data in the same code field; and may result in wasting radio channel resources due to the absence of an electronic tag in a certain code domain.
4) Host arbitration: and when the tag response data collide, the RFID host machine performs collision correction: sending an arbitration command in a specific channel time slot, stopping sending response data after the RFID tag receives the arbitration command, and sending the response data again after random delay; this method cannot effectively reduce collision of already-occurring response data, and may cause re-collision due to random delay, resulting in inefficient use of channel time slots.
5) Channel detection: the RFID label firstly carries out channel CAD detection before sending the response data, when the channel time slot is idle, the label response data is sent, otherwise, the CAD detection is carried out after random time delay; the method can effectively avoid collision, but due to the randomness and time occupation of starting CAD detection, the possibility of collision with a larger probability still exists when the label data volume is larger, and the power consumption is increased due to the long time of the CAD detection of the electronic label.
The anti-collision technical method for the RFID tag response data has different advantages and defects, but still does not fundamentally solve the balance problem between avoiding response collision and improving the utilization efficiency of a channel, and comprises the following steps: 1) How to rapidly wake up or rapidly excite the low-power-consumption RFID label; 2) How to detect the code domain distribution of label codes in the excitation group reading process; 3) How to allocate the RFID label response channel to solve the imbalance of channel resource allocation; 4) How to make RFID tags more aggressive in utilizing free channel time slots in collision avoidance conditions.
In the group reading process of the RFID tag slave computer by the RFID host computer, the transient channel resource utilization efficiency of subsequent group reading response can be dynamically optimized by adjusting and changing the wireless response channel distribution of the RFID tags and appointing corresponding response time slots according to the code domain characteristics (including the number, the coding range, the group, the sensitive bit section, other coding characteristics and the like) of the currently known target group RFID tag codes, and the time slot collision problem of the response data of the RFID tags in multi-computer communication is avoided.
Therefore, how to rapidly wake up and excite the low-power-consumption RFID tags, rapidly detect the code domain distribution of the tags, effectively allocate the channel time slots for the tag response, solve the imbalance of channel resource allocation, avoid tag response data collision, improve the utilization efficiency of the transient channel time slots, and improve the group reading receiving efficiency, response speed and success rate of the RFID host for a large number of RFID tags, which is a technical problem to be solved urgently.
Disclosure of Invention
The technical problem to be solved by the invention is that the RFID host carries out time code distribution detection on code clock pulse signals sent by RFID labels to obtain code domain distribution of response channels of different labels so as to solve the problem of rapid detection on code domain distribution of unknown label codes; the RFID host adjusts the channel code domain identification according to the code domain distribution feedback, and reads and receives the label data frame sent by the RFID label in different label channel time slots in a group manner so as to solve the problem of response time slot data conflict; through the rapid code domain detection, the utilization efficiency of the time slot of the RFID response channel is improved, and therefore the response success rate and the data receiving efficiency of RFID group reading are improved.
In order to solve the above problems, the present invention provides a method and an apparatus for detecting an RFID tag.
In a first aspect, the present invention discloses a method for detecting RFID tags, in which a certain RFID host obtains code domain distribution of a plurality of RFID tags through wireless detection, and feeds back and adjusts channel time slot parameters corresponding to RFID tag codes, so as to improve group reading efficiency of receiving data frames of the RFID tags, including the following steps: the RFID host sends a synchronous excitation signal containing a channel code domain identifier in a synchronous channel to ensure that the RFID label obtains time synchronization and sends a code clock pulse signal in a specified label channel time slot by code time conversion; the RFID host carries out time code distribution detection on the code clock pulse signal sent by the RFID label to obtain code domain distribution of different label response channels through time code conversion; the RFID host adjusts the channel code domain identification according to the code domain distribution feedback and updates and sends a corresponding synchronous excitation signal; and the RFID host reads and receives the label data frame sent by the RFID label in different label channel time slots.
Optionally, the RFID tag receives the synchronous excitation signal, transmits a code clock signal through a segment code time conversion in a synchronous reply period based on time synchronization.
Optionally, the code clock pulse signal refers to a wireless modulation pulse signal with an ultrashort pulse width obtained through code-time conversion, and is used for performing time code distribution detection by the RFID host.
Optionally, the code time conversion is a conversion mode that maps code domain distribution to time domain distribution; and the RFID tag obtains code clock pulse time by code-time conversion according to the channel tag code X' in a synchronous response period of the tag response channel, and sends the code clock pulse signal.
Optionally, the time code conversion is a conversion for estimating a code domain distribution according to a time domain distribution; the time code distribution detection is that the host obtains the time domain distribution of a plurality of code clock pulse signals through wireless scanning detection, and obtains the corresponding code domain distribution through time code conversion.
Optionally, the RFID tag obtains a corresponding channel time slot parameter according to the currently received channel code domain identifier, the channel tag code and the channel code width thereof, and the ratio of the code domain interval.
Optionally, if the code width read by the current group is larger than the channel rated code width, the RFID host performs group synchronous excitation on the RFID tag group by adjusting the set group code identifier and/or the channel code field identifier and sending the synchronous data frame containing the update identifier.
Optionally, the RFID tag dynamically adjusts the channel time slot parameter according to the channel code field identifier, and sends a tag data frame with a designated time slot priority in a tag response time slot in a synchronous response period.
Optionally, the time slot priority is a contention priority that the RFID tag allows to send its own response data frame in the same response time slot; the time slot priority corresponds to the time slot delay step of the preset sending time of the current response time slot.
Optionally, when the RFID host receives a tag data frame sent by the RFID tag, the RFID host sends a check data frame as an asynchronous response to the RFID tag in one of the following manners: mode one the RFID host immediately occupies the immediately following response time slot, sends the verification data frame with the highest time slot priority, and at this time, other RFID tags do not send tag data frames any more through time slot detection; and the RFID host occupies a certain idle response time slot through time slot detection and sends the verification data frame to one or more RFID labels.
Optionally, the RFID tag sends a tag data frame within a first tag response time slot according to a time slot priority consistent with a code clock time slot; and the RFID label carries out channel time slot detection before sending the label data frame, and allows the RFID label to be sent when the returned result is that the channel time slot is idle, otherwise, the time slot priority is adjusted in the next response time slot according to a mode of circularly increasing the priority.
In a second aspect, the present invention further discloses a device for detecting RFID tags, where the device is an RFID host, and the RFID host obtains code domain distribution of a plurality of RFID tags through wireless detection, and feeds back and adjusts channel timeslot parameters corresponding to RFID tag codes, so as to improve group reading efficiency of receiving data frames of the RFID tags, and the device is composed of the following modules: a synchronization module: the system is used for sending a synchronous excitation signal containing a channel code domain identifier on a synchronous channel, so that the RFID label obtains time synchronization, and sending a code clock signal on a designated label channel; a detection module: the system is used for carrying out time code distribution detection on code clock pulse signals sent by the RFID tags in a synchronous response period so as to obtain code domain distribution of different tag response channels through time code conversion; a feedback module: the system is used for adjusting the channel code domain identification according to the code domain distribution feedback and updating and sending a corresponding synchronous excitation signal; a receiving module: the RFID tag is used for group reading and receiving the tag data frame sent by the RFID tag in different tag channel time slots.
According to the technical scheme provided by the invention, after being awakened, the RFID tag receives the synchronous data frame which is sent by the host and is contained in the synchronous excitation signal in the specified synchronous channel; therefore, the balance efficiency of low power consumption and triggering corresponding to wake-up excitation and time synchronization is improved; according to the channel code domain identification in the synchronous data frame, based on the label coding calculation of the RFID label, the RFID label can rapidly obtain the time slot parameter of the adjusting channel; and sending tag response information in the appointed tag response channel and the response time slot thereof according to the channel time slot parameter, solving the problem of response time slot data conflict, and improving the utilization efficiency of the RFID response channel time slot so as to improve the RFID group reading receiving efficiency.
Therefore, compared with the prior art, the method and the device adjust the channel time slot parameters of the RFID label response through the channel code domain identification, improve the utilization efficiency of channel time slot resources, avoid the group reading label response conflict, and have remarkable technical effects and benefits on the group reading receiving label data frames of the active electronic label with low power consumption, quick awakening synchronization and high efficiency.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a flowchart illustrating a method for detecting an RFID tag according to an embodiment of the present invention;
FIG. 2 is a block diagram of a detecting device for RFID tags according to an embodiment of the present invention;
FIG. 3 is a timing diagram comparing signals of a synchronization channel and a tag response channel in a RFID tag group reading process according to an embodiment of the present invention;
FIG. 4 is a timing diagram illustrating the time slot composition and response signals in a synchronous response period of a tag response channel during a RFID tag group read response process according to an embodiment of the present invention;
fig. 5 is a timing diagram of a segmented code timing pulse signal of a code timing pulse time slot in a synchronous reply period of a tag reply channel in the RFID tag group read reply process according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It is to be understood that the described embodiments are part of the invention, and not all embodiments, are intended to be illustrative of the invention and are not limiting of the invention.
In a first embodiment, please refer to fig. 1, which is a flowchart of a method for detecting RFID tags disclosed in this embodiment, a certain RFID host wirelessly detects different tag channel time slots to obtain a plurality of RFID tags as code domain distribution of an active electronic tag, and feeds back and adjusts channel time slot parameters corresponding to RFID tag codes to improve group reading efficiency of receiving data frames of the RFID tags, and specifically includes the following steps:
step S101, the RFID host sends a synchronous excitation signal containing a channel code domain identifier in a specified synchronous channel to enable the RFID label to obtain time synchronization, and converts a code clock pulse signal sent in a specified label channel time slot in a sectional code mode;
step S102, the RFID host carries out time code distribution detection on the code clock pulse signal sent by the RFID label in the code clock pulse time slot in the synchronous response period, and obtains the code domain distribution of different label response channels through segmented time code conversion;
step S103, the RFID host adjusts the channel code domain identification according to the code domain distribution feedback, and updates and sends a corresponding synchronous excitation signal;
and step S104, the RFID host receives the label data frame sent by the RFID label in the label response time slot by wireless scanning detection group reading in different label channel time slots.
The implementation of the above steps is further explained as follows:
the synchronous excitation signal is composed of a series of wake-up excitation signals and synchronous data frame signals and is respectively used for waking up the RFID tag and obtaining time synchronization; and the RFID host respectively sends the awakening excitation signal and the synchronous data frame signal on the same or different channels. The RFID tag obtains the time synchronization by receiving a wireless synchronization identifier and performing synchronization time correction.
The synchronization data frame contains a wireless synchronization identifier, and the RFID tag obtains the time synchronization according to the synchronization identifier; and the RFID host sends the synchronous identification at least once in one synchronous period. The synchronization period refers to a period in which the RFID host transmits synchronization data frames, which may include one or more synchronization response periods.
The synchronization mark is a wireless modulation pulse signal used for time synchronization; the synchronization mark comprises or follows a synchronization offset code, and the synchronization offset code is a code corresponding to synchronization offset time, namely synchronization offset; the synchronization mark is located before a synchronization data frame (with a certain gap or starting position); when an isochronous packet comprises several isochronous frames, it contains at least one isochronous identity.
The RFID host obtains a synchronization offset sequence number for avoiding local collision through one or a combination of the following modes: 1) Specified by the system host/server; 2) Performing wireless detection learning by synchronous identification sent by other peripheral RFID hosts; 3) And actively adjusting by the RFID host with low priority according to the synchronization priority.
The synchronization shift amount (i.e., synchronization shift time) is a synchronization phase time based on a synchronization time step magnification, and the synchronization phase time is a shift time with respect to the synchronization shift amount of 0.
The synchronous response period is a period allocated to the multi-tag to send the tag response information, and includes a code clock time slot (C/T time slot for short) and a tag response time slot. The code clock time slot is a time slot for transmitting a code clock signal by the RFID tag.
The awakening excitation pulse is a wireless modulation pulse signal with ultrashort pulse width sent by the RFID host, and is used for carrying out primary preparatory awakening on the RFID label in a low-power-consumption sleep state before the RFID label obtains time synchronization; when the RFID label receives the wake-up excitation pulse in the transient detection time slot, the RFID label is immediately woken up.
The wake-up excitation pulse is a series of wireless modulation pulse signals which are sent by the RFID host and have extremely short pulse width time which is far less than one data frame (typically not more than microsecond).
The RFID label keeps a low-power-consumption sleep-following state in an un-awakening normal state, and is awakened by receiving the awakening excitation pulse signal through transient detection before the RFID label obtains the time synchronization; and if the RFID label fails to receive at least one wake-up excitation pulse in the micro time slot delta t of transient detection, immediately returning to the low-power-consumption sleep-following state.
The transient detection refers to wireless detection in a micro time slot delta t formed by transient flashing on/off of a specified high-frequency channel;
the time window width of the minislot at is at least larger than the pulse width of one or more wake-up excitation pulses. The transient detection is initiated by a timer or signal trigger, which may be of the type GPIO level transitions, passive low frequency signals, radiation/photo-induced signals, and other types of sense-coupled signals.
After the RFID label is awakened, after receiving the wireless synchronous identification sent by the RFID host in the synchronous detection time slot, continuously receiving the channel code domain identification following the synchronous identification. The channel code field identifier is included in the synchronization data frame. The RFID label checks the group code identification following the synchronous identification, and 1) if the group code identification fails to pass the check, the RFID label immediately returns to the low-power-consumption sleep-following state; 2) And if the verification is passed, continuously reading the channel code domain identification, and starting a synchronous response cycle according to the channel code domain identification and the synchronous time.
The channel code domain identification is a wireless identification for allocating, adjusting and indicating code domain intervals of a plurality of different channels and the distribution of the quantity values of the code domain intervals; the magnitude distribution includes an absolute quantity, a distribution ratio, or an adjustment quantity (e.g., an increment, a proportional increment).
The code clock pulse signal (C/T signal for short) is a wireless modulation pulse signal which is sent by the RFID tag and has a very short time (much shorter than a tag data frame) relative to the tag data frame; the code clock pulse signal is a series of radio modulated pulse signals with extremely short pulse width (typically not more than microsecond) transmitted by a plurality of RFID tags in a specified code clock pulse time slot.
The synchronous channel is a channel for enabling a plurality of RFID labels to obtain time synchronization; and the RFID tag obtains time synchronization by receiving the wireless synchronization identification sent by the RFID host and performing synchronization time correction.
The tag response channel (tag channel for short) is a channel through which the RFID tag sends tag data frames. The tag response channel is a communication channel for the RFID tag to transmit tag response data, and the channel is a radio frequency channel based on frequency and/or time division.
The label response channel is a series of synchronous response periods keeping time synchronization according to the synchronous excitation signal, and the RFID label sends label response information according to the channel time slot parameter in the label synchronous response period.
The channel time slot parameter refers to a channel and a time slot parameter where the assigned tag response is distributed; for example, the channel codes and corresponding frequency parameters, timeslot codes, timeslot priorities and corresponding timeslot delays are included.
The label data frame is a data frame containing label coding; and the label data frame is a data frame which is sent by the RFID label in the label response time slot and contains the self label coding information. The tag code can be the tag ID (such as MAC address or application ID) itself or reversible coding information after mapping conversion; it should be noted that, code domain conversion calculation may be performed according to the irreversible hash tag encoding, and a tag response channel and a corresponding channel timeslot parameter are allocated.
The channel code domain identifier is a wireless identifier describing channel code domain parameters; the channel code domain parameters refer to parameters of code domain ranges or intervals of the label codes corresponding to different label response channels (of course, the channel may be other than the channel). Optionally, the channel code domain parameter is a parameter or an identifier of a code width corresponding to different channels; of course, code widths outside of the channel may be included.
Referring to fig. 3, a timing chart of a comparison between signals of a synchronization channel and a tag response channel in a RFID tag group reading process in the embodiment of the present invention includes a timing chart of signals of a synchronization channel 310, a synchronization channel 320, and a tag response channel 330, which is specifically described as follows:
synchronization channel 310: the RFID host sends a wake-up excitation pulse signal 311 on the synchronization channel 310;
synchronization channel 320: the RFID host sends a series of synchronization data frames 321 in a synchronization channel 320, where each synchronization data frame includes one or more synchronization identifiers 3211, 3212 …; the synchronization marks 3211, 3212 … are synchronization offsets (i.e., synchronization offset times) 3201, 3202 …, respectively, with respect to a time difference of a start time (assuming that a synchronization phase time is 0) of the synchronization response cycle 3301;
tag reply channel 330: the RFID host transmits tag reply information during a series of synchronous reply cycles 3301 in the tag reply channel 330, including: transmitting a code clock signal 3311 in the code clock slot 331 and a tag response frame 3321 in the tag response slot 332;
it should be noted that the synchronization channels 310 and 320 may be the same or different synchronization channels.
Example two, the implementation of the steps of the flow chart previously described with reference to fig. 1 is further illustrated as follows:
the RFID tag receives the synchronous excitation signal, and transmits a code clock signal through a code clock time slot in a synchronous response period by section code clock conversion based on time synchronization.
The code clock time slot is contained in a synchronous reply period; the code clock signal is a preamble response signal sent by the RFID tag in the code clock time slot, and is used for detecting the distribution of the time code by the RFID host.
The code time pulse signal (C/T signal for short) is a wireless modulation pulse signal with ultrashort pulse width obtained by code time conversion, and is used for detecting time code distribution by the RFID host.
The RFID host machine carries out the time code distribution detection by monitoring the distribution quantity of the time slot activity of the code clock pulse signals of different channels through wireless scanning detection.
The code time conversion (i.e., C/T conversion) is a conversion manner that maps code domain distribution to time domain distribution; and the RFID tag obtains code clock pulse time by code-time conversion according to the channel tag code X' in a synchronous response period of the tag response channel, and sends the code clock pulse signal.
The code clock pulse time T ' = X ' × Δ T/Δ Xw, where X ' is channel label coding, Δ T is code time division step size, and the code time division step size refers to a time step size corresponding to a minimum code width Δ Xw (default is 1).
The Code Time conversion (or C/T conversion) refers to the conversion of the tag Code from the Code domain (Code domain) to the Time domain (Time domain); the label code X is first converted into channel label code X' and then converted into code clock time in proportion.
When the channel tag code X 'transmits a code clock signal in multi-slots, the segment code in the channel tag code X' is code-time converted every slot. When the code clock pulse slot Tp includes a plurality of slots, the code time conversion includes a plurality of times of segment code time conversion, and the slot distribution of the tag-encoded segment code is obtained by each segment code time conversion.
The RFID tag converts the tag code X of the RFID tag into pulse sending time in a code clock pulse time slot Tp in a linear and/or random mode through the code time conversion according to the current channel code width Wi.
The code clock pulse time slot refers to a time slot allowing different tags to send the code clock pulse signal in the synchronous response period in the current tag response channel i; the pulse transmission time Tc is the relative time t of the RFID tag for transmitting the code clock pulse signal within the code clock pulse time slot Tp, which is obtained based on the code time conversion; t ∈ [0, tp).
The time code conversion (i.e. T/C conversion) is a conversion for estimating the code domain distribution according to the time domain distribution; the time code distribution detection is that the host obtains the time domain distribution of a plurality of code clock signals through wireless scanning detection, and obtains corresponding code domain distribution through time code conversion.
The channel label code X ' = T ' × Δ Xw/Δ T, where T ' is a code pulse time, Δ T is a code time resolution step size, and the code time resolution step size refers to a time step size corresponding to a minimum code width Δ Xw (default 1).
The Time Code conversion (or T/C conversion) refers to the conversion of Time domain pulses from Time domain (Time domain) to Code domain (Code domain); the code clock pulse time t is firstly converted into the channel label code X 'or the code domain interval which is subordinate to the channel label code X' in proportion.
When the channel tag code X 'transmits a code clock signal in multi-slots, the segment code in the channel tag code X' is time-code converted every slot. When the code clock pulse time slot Tp includes a plurality of time slots, the time code conversion includes a plurality of times of segmented time code conversion, and the code domain distribution of the label-coded segmented code is obtained by each time of segmented time code conversion.
Referring to fig. 4, a time slot composition and a response signal timing chart in a synchronous response period 400 of a tag response channel in the RFID tag group read response process according to an embodiment of the present invention are shown, where the synchronous response period 400 includes a code clock time slot 410 and a tag/asynchronous response time slot 420, and the following description specifically refers to:
code clock time slot 410: a plurality of RFID tags pass code time conversion, and code time pulses 4101, 4102 … with different code time pulse sending time (relative time is t) are sent in the code time pulse time slot 410;
tag/asynchronous reply slot 420: the RFID tag comprises a plurality of tag response time slots 421, 422, 423 and … X, and a certain RFID tag sends a tag data frame 4211 based on time slot priority; other RFID tags with relatively low time slot priority are subjected to channel time slot detection, and tag data frames 4212, 4213 and … X are forbidden to be sent so as to avoid time slot response data collision; where Td is the maximum allowed value of the slot delay step.
When the RFID host needs to perform asynchronous response, it can choose to occupy (or find free based on channel timeslot detection) the tag response timeslot 42X with the highest timeslot priority, and send the host asynchronous response frame 42X0.
Referring to fig. 5, it is shown a timing chart of a segmented code clock signal of a code clock time slot 500 in a synchronous reply period of a tag reply channel in an embodiment of the present invention, where the code clock time slot 500 includes a plurality of code clock time slots 510, 511, 512, 513, and performs segmented code time conversion on segmented codes (i.e. segment codes) included in channel tag codes 501 of a plurality of RFID tags;
the channel label coding 501 in fig. 5 includes a segmentation code which is a bit segment (nibble) formed by a 4-bit binary system, so that the segmentation value range is: 0x0 to 0xf.
Example three, the implementation of the steps of the flow chart previously described with reference to fig. 1 is further illustrated as follows:
and the RFID label obtains a corresponding channel time slot parameter according to the currently received channel code domain identification, the self channel label code X' and the channel code width and the proportion of the code domain interval.
When the RFID tag is awakened in any awakening mode, the RFID tag continues to try to receive the synchronous identification in a specified synchronous detection time slot:
1) If the RFID label does not receive the synchronous identification in the appointed synchronous detection time slot, the RFID label immediately returns to the low-power-consumption sleep-following state;
2) And if the RFID tag receives the synchronous identification in the synchronous detection time slot, the RFID tag is immediately awakened synchronously to obtain time synchronization, synchronous time correction is carried out according to a synchronous offset code following the synchronous identification, and a synchronous response period is started according to the synchronous time according to the channel code domain identification.
The synchronous detection time slot is a wireless detection time slot for trying to receive the synchronous identification; the synchronization detection time slot is at least larger than the sending interval time of one or more series of synchronization marks.
The channel code domain identifier is a code identifier describing code widths corresponding to different label response channels, and comprises one or a combination of the following modes:
a code width code 0, a code width code 1, … are used, and the code width code i corresponds to a channel serial number i;
mode two channel code 0, channel code 1, …, said channel code j corresponding to a predetermined code width j;
in the third mode, one or more channel code widths are respectively assigned to a plurality of channels through channel bit selection codes.
The channel bit selection refers to the selection of different binary bits (one or more bits) corresponding to different channels, and the binary bit values represent the channel code width parameters corresponding to different code width codes.
The code width code is one or a combination of the following modes:
the method one original code: a magnification based on a given code width unit (minimum 1);
the second complement method: a two's complement code relative to a given maximum code width (not greater than the total code width);
mode three bit code: different predetermined code widths are represented by one or a combination of bits.
The code width code comprises a code identification of an increment adjusting mode; the total code width is limited by group code identification and/or mapping transformation mode; optionally, the code width code includes a total channel code width and an unselected channel code width.
If the code width (or code width ratio) corresponding to any tag response channel i is w (i), the initial code of the channel i is:
x0 (i) = packet offset Xg + channel offset Xc (i); the group offset refers to the offset of the current excitation group relative to the total code domain range; the channel offset refers to the offset of the current response channel relative to a single group of limited code domain ranges; assuming that the current packet serial number is k and the nominal number of groups is n, xg = k/n × Wn, where Wn is the total code width of the label code, if there is no packet (i.e., k = n = 1).
The channel offset Xc (i) is obtained by summing the channel code widths smaller than i: xc (i) = ∑ w (i); when judging that X0 (i) < = X < X0 (i + 1), the RFID tag code X is allocated to a response channel i in the current synchronous response period.
The label code X refers to the ID code of the RFID label or a code obtained by performing code mapping transformation on the label ID code;
the code mapping transformation can be reversible transformation (non-compression code domain space), such as linear transformation and exclusive or operation; it may also be an irreversible transform (compressed code domain space), such as a HashMap transform. The mapping transformation function may be expressed as: x = Φ (ID, pi), where X is the label code X after mapping and Pi is the mapping parameter.
The label code X is a code which tries to make the code width of different code domain intervals approximately proportional to the expected label probability distribution; the probability distribution is proportional to the maximum number of labels that may occur in the code domain interval.
The segmented codes are subsets of the channel label codes X ', and the channel label codes X' are formed by overlapping a plurality of segmented codes; the segment code comprises one or more bytes or binary bit segments; for example, the segments are encoded as half bytes, one byte, or two bytes, etc. The segment code may encode the channel label or a subset thereof, formed by a binary shift.
The tag code is formed by superimposing several bit segments, which comprise one or more binary bits.
The channel label code X' is a label code which is subjected to retransformation processing on a certain channel; the channel label code X' is an offset code that maps the label code against the code domain reference of a given channel. When the label response channel is distributed by grouping excitation or synchronous multi-channel excitation, the label coding is replaced by the channel label coding X', so that the code domain interval in the same channel is greatly reduced.
If the channel start code X0 is taken as the code domain reference, the channel tag code X' can be expressed as: x' = X-X0, wherein X0 is the channel start coding. The channel start code refers to a start boundary value of the tag code assigned to a specific tag response channel.
And if the code width read by the currently set target group is larger than the channel rated code width, the RFID host performs grouping synchronous excitation on the RFID label group by adjusting and setting a group code identifier and/or a channel code domain identifier and sending a synchronous data frame containing an updating identifier.
The group code identification is a wireless identification used for limiting a code domain space of the RFID label code; the channel code domain identifier is a total code width defined based on the group code identifier and/or the mapping transformation mode, and further describes the distribution of the code domain channels. And after the RFID host updates the groups, carrying out time code distribution detection on the code time pulse signals in a new synchronous response period.
Example four, the following is further illustrated for the implementation of the steps of the flow chart previously described with reference to fig. 1:
and the RFID label dynamically adjusts the channel time slot parameters according to the channel code domain identification, and sends a label data frame with a specified time slot priority in the label response time slot in the synchronous response period.
The time slot priority is the competition priority of the RFID label which allows to send the self response data frame in the same response time slot; the time slot priority corresponds to the time slot delay step of the preset sending time of the current response time slot.
When the delay step is larger than the maximum allowable value, the tag data frame is not allowed to be sent in the current response time slot; when the delay step corresponding to the time slot priority of the RFID label is larger than the maximum allowable value, forbidding sending a response data frame in the current response time slot; it may wait to find a tag acknowledgement slot that allows it to transmit a tag data frame in a subsequent acknowledgement slot or subsequent synchronous acknowledgement period.
Before the RFID label sends the response data frame according to the delay step length corresponding to the time slot priority, channel time slot detection condition exemption is carried out to be the highest time slot priority; and if and only if the return result of the time slot detection is that the channel time slot is idle, allowing to transmit, otherwise, forbidding to transmit the response data frame in the current response time slot. The lower the priority, the larger the delay step without exceeding the maximum allowed delay.
The time slot delay step refers to a step length corresponding to a preset time for sending a response data frame of the current response time slot; one time slot priority corresponds to one delay step, and one delay step is increased when one time slot priority is reduced. In the actual development process, the slot priorities may be defined as follows: time slot priority 0, delay step 0; time slot priority 1, delay step 1; …; time slot priority n, delay step n.
In a synchronous response period, if the RFID label fails to successfully send the label data frame in a certain label response time slot, or does not receive response verification information of the RFID host or fails to verify, the RFID label adjusts the time slot priority of sending the label data frame in the subsequent response time slot according to a mode of circularly increasing the priority.
When a plurality of label response time slots exist in a synchronous response period, the priority is increased according to the circulation; if the time slot priority of the current response time slot is the highest level, the time slot priority of the next response time slot is adjusted to be the lowest level, but not the time slot priority of the highest level, and a priority is increased in the next response time slot.
The tag response time slot (response time slot for short) is a time slot for sending tag data frames by the RFID tag; a synchronous reply period may comprise one multi-tag reply slot or a plurality of single-tag reply slots.
When the RFID host receives a tag data frame sent by the RFID tag in a tag response channel, one or more RFID tags send check data frames serving as asynchronous responses in one of the following ways:
mode one the RFID host immediately occupies the immediately following response time slot, sends the verification data frame with the highest time slot priority, and at this time, other RFID tags do not send tag data frames any more through time slot detection;
and the RFID host occupies a certain idle response time slot through time slot detection and sends the verification data frame to one or more RFID labels.
When the RFID host receives a certain tag data frame in a certain tag response time slot, the RFID host transmits an authentication data frame as an asynchronous response to the RFID tag in a subsequent tag response time slot. And the RFID host sends the verification data frame for smooth response and control instruction to the specified label data frame through the asynchronous response.
After a certain RFID label receives the response information of the RFID host, the RFID label can be used as a relay agent node to provide relay agent service for other RFID labels nearby in a help seeking state according to the relay agent condition; after receiving a help data frame sent by an adjacent RFID label, the relay agent node immediately sends an agent label data frame at a subsequent asynchronous response time slot when a certain response time slot is idle based on channel time slot detection; the help data frame is a label data frame containing a help mark.
When a certain RFID tag is repeatedly and synchronously excited again in a short time, if a certain relay agent node receives a tag data frame sent by the RFID tag in the previous cycle, the cycle has the time slot priority of the agent response.
The RFID label sends a label data frame within a first label response time slot according to the time slot priority consistent with the code clock time slot; and the RFID tag carries out channel time slot detection before sending the tag data frame, and allows sending if and only if the returned result of the time slot detection is that the channel time slot is idle, otherwise, the time slot priority is adjusted in the next response time slot according to a mode of circularly increasing the priority.
After the RFID tag determines the time slot delay step length, the time slot priority of each single tag response time slot can be consistent with the code pulse time, but different code width time step lengths are determined according to the minimum code width; the code width time step refers to the minimum time step corresponding to the minimum code width.
The RFID tag identifies the corresponding check position identification in the synchronous response check identification to judge whether the previously sent tag data frame is received by the RFID host;
the check bit identification can reflect response check information of a plurality of label response time slots in the current period; the verification response information of whether the tag data frames of different tag response time slots are received in the previous N periods can also be represented by different bits or bit segments through rolling iteration.
According to the received synchronous response check identification, when the RFID label judges that the label data frame sent by the RFID label is received by the RFID host, the RFID label can immediately stop sending the label response information; otherwise, waiting for receiving a new synchronous data frame sent by the RFID host, and sending the label response information according to the updated channel time slot parameter in the new synchronous response period. Otherwise, waiting for receiving a new synchronous data frame sent by the RFID host, and sending label response information according to the updated channel time slot parameter in the new synchronous response period.
The time slot detection, i.e. channel time slot detection (i.e. TSD detection), is a tentative wireless detection performed by the RFID tag before sending data in a specified channel time slot, and is intended to determine whether the current channel time slot is idle. The RFID tag is used for judging whether the current response time slot is idle or not before sending a response data frame by carrying out the time slot detection (namely TSD detection) on the response time slot of the current tag, so as to avoid channel collision; optionally, the RFID tag calculates a time slot delay step size and a corresponding time slot priority of the tag data frame by detecting and identifying all or end features (such as an identification end symbol or an end time) of the tag data frame sent by other RFID tags in the current response time slot.
When the RFID tag judges that the time slot priority of the tag data frame actually sent by the current response time slot is reduced by n levels through channel time slot detection, n +1 levels are allowed to be increased at most in the next response time slot of the same synchronous response period, namely n +1 delay steps are advanced. The RFID tag calculates the time slot delay step length of the current tag data frame and the corresponding time slot priority by detecting and identifying all or ending characteristics (such as an identification special ending symbol or ending time) of tag data frames sent by other RFID tags in the current response time slot.
Example five, the implementation of the steps of the flow chart previously described with reference to fig. 1 is further illustrated as follows:
the primary wake-up excitation signal for preparing the RFID tag can be a low-frequency wake-up signal or a modulation signal of a radio-frequency wake-up excitation pulse; and receiving the low-frequency wake-up signal through a low-frequency passive antenna, and obtaining the receiving response of the low-frequency coupling signal.
When the RFID host performs synchronous excitation group reading, the RFID host sets the group code check identifier in the sent synchronous data frame to perform the group synchronous excitation, and the method comprises one or a combination of the following modes: 1) And the mode of non-matching with the specified group code: to read the RFID tag of the newly added item; 2) And the mode of matching with the specified group code is as follows: to verify the RFID tag of the removed item.
And after receiving the synchronous identification, the RFID label immediately corrects the synchronous time according to the synchronous offset time corresponding to the synchronous offset code, and sends a label data frame of the RFID label in a specified channel time slot in a synchronous response period based on time synchronization.
And after receiving the synchronous identification, the RFID label immediately corrects the synchronous time according to the synchronous offset time corresponding to the synchronous offset code, and sends a label data frame of the RFID label in a specified channel time slot in a synchronous response period based on time synchronization.
When the RFID host learns the wireless synchronization identifier sent by the nearby cooperative RFID host through detection, and according to the synchronization offset codes of the two parties, when the synchronization offset time of the RFID host is inconsistent with the synchronization offset code, the synchronization offset correction is carried out on the synchronization offset time of the wireless synchronization identifier actually sent by the RFID host.
The RFID host adjusts the corresponding hash transformation identifier according to the segmented code domain distribution of the RFID label obtained by a detection and/or prediction mode at present, and is used for encoding mapping transformation (hash transformation): converting the RFID tag code to a hash tag code;
and the RFID label receives the Hash transformation identifier contained in the synchronous data frame based on time synchronization, performs coding mapping transformation according to the Hash transformation identifier, and converts the label code of the RFID label into Hash label code according to Hash bit segment transformation.
And the RFID label calculates corresponding channel time slot parameters according to the Hash label code, and sends a label data frame at a specified time slot response time slot according to a specified time slot priority.
The RFID host carries out synchronous response on the received label data frames sent by the RFID labels in different label response time slots in the synchronous response period by updating the synchronous response check marks in the synchronous data frames;
the hash bit segment transformations are associated with current synchronization identification information such that when a hash tag encoding one synchronization response period of two or more RFID tags encounters a conflict, then at the next synchronization response period, there will be no further continuous conflicts; the synchronization identification information refers to indication information associated with the current synchronization period, such as a synchronization sequence number and an offset code.
And if the RFID label receives the synchronous response check identification sent by the RFID host, when the sent label data frame is identified and judged to be received by the RFID host, sending the label response information and the label data frame thereof can be immediately stopped.
And when the transmitted tag data frame is identified and judged to be not received by the RFID host, the time slot detection may still be performed with a low time slot priority within the tag response time slot following the same tag response period, and the tag data frame is transmitted again under the condition that the time slot is idle.
If the RFID label fails to successfully send the label data frame in a synchronous response period, waiting for receiving an updated synchronous data frame sent by an RFID host; the synchronous data frame comprises the Hash transformation identifier and the synchronous response verification identifier.
And the RFID label receives the Hash transformation identifier contained in the synchronous data frame based on time synchronization, performs coding mapping transformation according to the Hash transformation identifier, and converts the label code of the RFID label into Hash label code according to Hash bit segment transformation.
The hash transformation identifier is a wireless identifier reflecting hash bit segment transformation parameters; the hash bit segment transformation parameters are mapping transformation parameters Pi for carrying out the hash bit segment transformation, and comprise parameters of selection and combination modes of the hash bit segment; the hash bit segment transform is a sensitive bit segment based hash map transform of the tag code; the hash bit segment conversion parameter is a hash bit segment code composed of a bit selection code or a bit segment selection code.
The hash bit segment transform is a hashed mapping transform of the tag code based on the sensitive bit segment; and the RFID label maps and transforms the label code of the RFID label into a new hash label code through the hash bit segment transformation, replaces the original label code with the hash label code and calculates the channel time slot parameter for sending the label response data.
The hash bit segment transforms into a mapping transform that hashes a number of hash bit segments (hash-sensitive bit segments) contained in the label encoding and recombines (sorts, shifts, superposes).
The embodiment of the present invention further discloses a device for detecting RFID tags, please refer to fig. 2, the device is an RFID host, the RFID host uses a plurality of RFID tags obtained by wirelessly detecting different tag channel time slots as code domain distribution of an active electronic tag, and feeds back and adjusts channel time slot parameters corresponding to RFID tag codes, so as to improve group reading efficiency of receiving data frames of the RFID tags, and the device 200 includes: a synchronization module 201, a detection module 202, a feedback module 203, and a receiving module 204, wherein:
the synchronization module 201: the RFID tag is used for transmitting a synchronous excitation signal containing a channel code domain identifier on a designated synchronous channel, enabling the RFID tag to obtain time synchronization and converting a pulse signal when a code is transmitted on the designated tag channel in a segmented code time;
the detection module 202: the system comprises a time code distribution detection module, a time code conversion module and a time code conversion module, wherein the time code distribution detection module is used for carrying out time code distribution detection on a code clock pulse signal sent by an RFID label in a code clock pulse time slot in a synchronous response period so as to obtain code domain distribution of different label response channels through segmented time code conversion;
the feedback module 203: the system is used for adjusting the channel code domain identification according to the code domain distribution feedback and updating and sending a corresponding synchronous excitation signal;
the receiving module 204: and the RFID tag is used for receiving the tag data frame sent by the RFID tag in the tag response time slot by the wireless scanning detection group reading in different tag channel time slots.
In practical implementation, the apparatus is a computer apparatus, and the processor executes computer instructions to implement the embodiment of the detection apparatus for an RFID tag disclosed above.
Those skilled in the art will appreciate that all or part of the processes in the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer readable storage medium and can include the processes of the embodiments of the methods described above when executed.
For several terms referred to in the foregoing embodiments, further description is as follows:
the RFID tag (which may be referred to simply as a tag depending on the context) is a wireless device that can be energized to transmit tag data frames on a designated channel and time slot. The channels generally refer to frequency channels; the tag data frame includes a tag ID or a type of tag encoding information that can be converted into a tag ID.
The active electronic tag is an active RFID tag; the active is able to transmit the tag reply signal using the tag's internal energy (e.g., battery, AC/DC).
The RFID host is a group of read hosts (which may be simply referred to as hosts according to context) and is a host device capable of synchronously exciting a plurality of RFID tags and simultaneously reading tag response information in a transient state. The RFID host serves as wireless communication equipment of a wireless communication base station or a wireless gateway.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. These should also be construed as the scope of the present invention, and they should not be construed as affecting the effectiveness of the practice of the present invention or the applicability of the patent. And are neither required nor exhaustive of all embodiments. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims. And obvious variations or modifications derived therefrom are intended to be within the scope of the invention.
Claims (13)
1. A method for detecting RFID labels is characterized in that a certain RFID host computer obtains code domain distribution of a plurality of RFID labels through wireless detection and feeds back and adjusts channel time slot parameters corresponding to RFID label codes so as to improve group reading efficiency of receiving RFID label data frames, and the method specifically comprises the following steps:
the RFID host sends a synchronous excitation signal containing a channel code domain identifier in a synchronous channel to ensure that the RFID label obtains time synchronization and sends a code clock pulse signal in a specified label channel time slot by code time conversion;
the RFID host carries out time code distribution detection on the code clock pulse signals sent by the RFID tags, and obtains the code domain distribution of different tag response channels through time code conversion;
the RFID host sends a synchronous excitation signal containing a channel code domain identifier in a synchronous channel to ensure that the RFID label obtains time synchronization and sends a code clock pulse signal in a specified label channel time slot by code time conversion;
the RFID host carries out time code distribution detection on the code clock pulse signal sent by the RFID label to obtain code domain distribution of different label response channels through time code conversion;
the RFID host adjusts the channel code domain identification according to the code domain distribution feedback, updates and sends a corresponding synchronous excitation signal, and the RFID label dynamically adjusts the channel time slot parameter according to the channel code domain identification;
and the RFID host reads and receives the label data frame sent by the RFID label in the label response time slot in different label channel time slots in a group mode.
2. A detection method for an RFID tag as claimed in claim 1, wherein the RFID tag receives the synchronous excitation signal and transmits a code clock signal through a segment code time conversion in a synchronous response period based on time synchronization.
3. A method as claimed in claim 1, wherein the code pulse signal is a wireless modulated pulse signal with ultra-short pulse width obtained by code-time conversion, and is used for detecting the distribution of time code by the RFID host.
4. A method as claimed in claim 1, wherein said code time conversion is a conversion of mapping code domain distribution to time domain distribution; and the RFID tag obtains code clock pulse time by code-time conversion according to the channel tag code X' in a synchronous response period of the tag response channel, and sends the code clock pulse signal.
5. A method as claimed in claim 1, wherein said time-code conversion is a conversion of the code domain distribution estimated from the time domain distribution; the time code distribution detection is that the host obtains the time domain distribution of a plurality of code clock signals through wireless scanning detection, and obtains corresponding code domain distribution through time code conversion.
6. A detection method for RFID tag as claimed in any of claims 1 to 5, wherein said RFID tag obtains the corresponding channel time slot parameter according to the currently received channel code domain identification, according to the self channel tag code X' and channel code width, and by the ratio calculation of code domain interval.
7. A detection method for RFID tag as claimed in any of claims 1 to 5, wherein said RFID tag dynamically adjusts said channel time slot parameter according to said channel code field identification, and transmits the tag data frame with the assigned time slot priority in the tag response time slot of the synchronous response period.
8. A detection method as claimed in claim 1 or 7, wherein said timeslot priority is a contention priority for allowing the RFID tag to transmit its own response data frame in the same response timeslot; the time slot priority corresponds to the time slot delay step of the preset sending time of the current response time slot.
9. A detection method for RFID tags as claimed in any one of claims 1 to 5, wherein said RFID host sends a verification data frame as an asynchronous response to said RFID tag when it receives a tag data frame sent by said RFID tag in a tag response channel by one of the following ways:
in the first mode, the RFID host immediately occupies the following response time slot, the verification data frame is sent at the highest time slot priority, and other RFID tags do not send the tag data frame any more through time slot detection;
and in the second mode, the RFID host occupies a certain idle response time slot through time slot detection and sends the verification data frame to one or more RFID labels.
10. A detection method for RFID tag as claimed in any of claims 1 to 5 wherein said RFID tag transmits its tag data frame in the first tag reply timeslot according to timeslot priority consistent with the code clock time slot;
and the RFID tag carries out channel time slot detection before sending the tag data frame, and allows the RFID tag to send the tag data frame if and only if the returned result is that the channel time slot is idle, otherwise, the time slot priority is adjusted in the next response time slot according to a mode of circularly increasing the priority.
11. A detection method for an RFID tag according to claim 1 or 6, wherein if the code width of the current group reading is larger than the channel rating code width, the RFID host performs packet synchronous excitation on the RFID tag group by adjusting the set group code identifier and/or the channel code field identifier and sending the synchronous data frame containing the update identifier.
12. A detection method for RFID labels as claimed in claim 1 or 4, characterized in that, said label response channel is a series of synchronous response periods keeping time synchronization according to said synchronous excitation signal, said RFID labels transmit label response information according to said channel time slot parameter in said label synchronous response period.
13. The device for detecting the RFID tags is characterized in that the device is an RFID host, the RFID host obtains code domain distribution of a plurality of RFID tags through wireless detection and feeds back and adjusts channel time slot parameters corresponding to RFID tag codes so as to improve the group reading efficiency of receiving RFID tag data frames, and the device is composed of the following modules:
a synchronization module: the system comprises a synchronous channel, an RFID tag and a clock pulse signal, wherein the synchronous channel is used for sending a synchronous excitation signal containing a channel code domain identifier, so that the RFID tag obtains time synchronization and sends a code clock pulse signal in a specified tag channel;
a detection module: the system is used for carrying out time code distribution detection on code clock pulse signals sent by the RFID tags in a synchronous response period so as to obtain code domain distribution of different tag response channels through time code conversion;
a feedback module: the RFID label dynamically adjusts the channel time slot parameters according to the channel code domain identifier;
a receiving module: and the RFID tag is used for group reading and receiving the tag data frame sent by the RFID tag in the tag response time slot in different tag channel time slots.
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