CN115618914B - Synchronous communication method and device based on RFID - Google Patents

Abstract

The invention discloses a synchronous communication method and a device based on RFID, wherein an RFID host machine receives response data of a plurality of RFID labels by group reading through sending synchronous excitation signals, and the method comprises the following steps: transmitting a synchronization frame included in the excitation signal on a synchronization channel; the received label data frames are synchronously responded by updating the synchronous response check mark; adjusting corresponding Hash transformation identifiers according to the code domain distribution of the currently obtained RFID label; and updating the Hash transformation identification and the synchronous response verification identification. And the RFID tags send tag response data in a plurality of channel time slots according to the currently received synchronous data frames and receive synchronous response information. The RFID host device comprises a synchronous excitation module, a code domain transformation module, a verification response module and an identification updating module; the RFID tag device comprises a mapping conversion module, a time slot response module and a verification judgment module. The invention improves the synchronous communication data efficiency of the RFID group reading channel time slot through synchronous code domain transformation and response verification.

Description

Synchronous communication method and device based on RFID

Technical Field

The invention relates to the technical field of wireless communication and edge intelligence of the Internet of things, mainly relates to signal timing sequence, data efficiency and flow mechanism of a Radio Frequency Identification (RFID) wireless communication data transceiving protocol layer, and particularly relates to a synchronous communication method and device based on RFID.

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 frequency channel and modulation mode, RFID air interface communication protocol specification, and RFID industry application coding specification (such as logistics, animals, articles 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 solves the problem that the transient communication data efficiency in the group reading process is needed to be solved, so that transient channel resources must be more effectively utilized; and the method is not like other wireless communication modes, which consumes more wireless channel resources to establish stable protocol handshaking 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 the collision of the RFID label 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 then 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; the method cannot effectively reduce the collision of the response data, and the collision is caused again due to random time delay, so that the utilization efficiency of the channel time slot is low.

5) Channel detection: the RFID label carries out channel CAD detection before sending the response data, the label response data is sent only when the channel time slot is idle, otherwise, the CAD detection is carried out after random 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 response data of the RFID tag 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 channels and solve the imbalance of channel 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, how to rapidly detect the code domain distribution of the RFID tags for the RFID tags with uncertain quantity and code domain distribution, and effectively allocate the channel time slots for tag response, thereby avoiding tag response data collision and improving the utilization efficiency of transient channel time slots; therefore, the group reading success rate and the synchronous communication data efficiency of the RFID host to a large number of RFID labels are improved, and the technical problem to be solved urgently is solved.

Disclosure of Invention

The invention aims to solve the technical problems that how an RFID host can more effectively wake up and excite an RFID label group and time synchronization is carried out so as to solve the balance problem of low-power consumption wake-up and high-efficiency synchronization; how the RFID host calculates the time slot of the response channel based on the code mapping transformation according to the code domain distribution of the RFID label so as to solve the balance problem of the utilization of the response channel of the label and avoid the time slot collision of the response data of the label; the RFID host machine solves the problem of response data efficiency by selecting asynchronous response or synchronous response; therefore, the transient utilization rate of wireless channel resources and the data efficiency of synchronous communication are improved.

In order to solve the above problems, the present invention provides a synchronous communication method and apparatus based on RFID.

In a first aspect, the present invention discloses a synchronous communication method based on RFID, wherein an RFID host sends a synchronous excitation signal to perform group reading and receiving on tag response data sent by a plurality of RFID tags, and the method specifically includes the following steps: the RFID host sends a synchronous data frame contained in the synchronous excitation signal in a synchronous channel to ensure that the RFID label obtains time synchronization; the RFID host adjusts corresponding Hash transformation identifiers according to the code domain distribution of the currently obtained RFID labels, and is used for converting the RFID label codes into Hash label codes; the RFID host carries out synchronous response on the received label data frame sent by the RFID label by updating the synchronous response check mark in the synchronous data frame; and the RFID host sends an updated synchronization data frame, wherein the synchronization data frame comprises the Hash transformation identifier and the synchronization response verification identifier.

In a second aspect, the present invention discloses another synchronous communication method based on RFID, where a plurality of RFID tags send tag response data in multiple channel slots according to currently received synchronous data frames sent by an RFID host, and receive synchronous response information sent by the RFID host, and the method specifically includes the following steps: the RFID label receives a 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; the RFID label calculates corresponding channel time slot parameters according to the Hash label code, and sends a label data frame in a specified label response time slot; the RFID label identifies and judges the received synchronous response check mark in the synchronous data frame: when the tag data frame has been received by the RFID host, the continued transmission of the tag data frame is immediately stopped.

Optionally, the synchronization data frame contains a wireless synchronization identifier, and the RFID tag obtains the time synchronization according to the synchronization identifier; the RFID host sends the synchronous identification at least once in a synchronous period; the synchronization mark is a wireless modulation pulse signal used for time synchronization; the synchronization mark contains or follows a synchronization offset code, which is a code corresponding to the synchronization offset time.

Optionally, when the RFID host learns the wireless synchronization identifier sent by another nearby cooperative RFID host by detecting, and according to the synchronization offset codes of the two parties, and when the synchronization offset time of the RFID host is inconsistent with the synchronization offset code, the synchronization offset time of the wireless synchronization identifier actually sent by the RFID host is subjected to synchronization offset correction.

Optionally, the RFID tag maintains a low-power-consumption sleep state in an un-wake-up normal state, and the RFID tag receives the wake-up excitation pulse signal through transient detection to be woken up before obtaining 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.

Optionally, after the RFID tag is awakened, after receiving the wireless synchronization identifier sent by the RFID host in the synchronization detection time slot, the RFID tag continues to receive the channel code domain identifier following the synchronization identifier; and the RFID label calculates corresponding channel time slot parameters based on the label code of the RFID label according to the channel code domain identification.

Optionally, the RFID host performs time-code distribution detection on the code clock pulse signal sent by the RFID tag, and obtains code domain distribution of different tag response channels through time-code conversion; the RFID host monitors the distribution quantity of the time slot activity of the code clock pulse signals of different channels simultaneously through wireless scanning detection, and the time code distribution detection is carried out.

Optionally, after the RFID tag is awakened, the RFID tag continues to attempt to receive the synchronization identifier within a specified synchronization detection time slot: 1) If the RFID label does not receive the synchronous identification in the appointed synchronous detection time slot, the low-power-consumption sleep-following state is immediately returned; 2) And if the RFID tag receives the synchronous identification in the synchronous detection time slot, immediately acquiring time synchronization, and starting a synchronous response cycle according to the synchronous time.

Optionally, if the RFID tag does not receive the response check identifier sent by the RFID host in a certain synchronous response period, perform timeslot detection with low timeslot priority in a subsequent tag response timeslot, and send the tag data frame again under a condition that the timeslot is determined to be idle.

Optionally, before the RFID tag sends its response data frame according to the delay step corresponding to the slot priority, channel slot detection is performed first; 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.

Optionally, the hash transform identifier is a wireless identifier reflecting hash bit segment parameters; the hash bit segment parameter is a hash bit segment code formed by bit selection codes or bit segment selection codes, and a mapping transformation parameter Pi for carrying out hash bit segment transformation according to the hash bit segment parameter comprises parameters of selection and combination modes of the hash bit segment; the hash bit segment transform is a sensitive bit segment based hashability mapping transform on the tag code.

In a third aspect, the present invention further discloses a synchronous communication device based on RFID, where the device is an RFID host device, and the RFID host sends a synchronous excitation signal to perform group reading and receiving on tag response data sent by a plurality of RFID tags, and the device is composed of the following modules: a synchronous excitation module: the RFID tag is used for transmitting a synchronous data frame contained in the synchronous excitation signal on a synchronous channel so as to obtain time synchronization of the RFID tag; code domain transformation module: the hash transformation identifier is used for adjusting the corresponding hash transformation identifier according to the code domain distribution of the currently obtained RFID label, so that the RFID label code is converted into a hash label code; the verification response module is used for: the synchronous response verification module is used for updating a synchronous response verification identifier in the synchronous data frame to carry out synchronous response on the received label data frame sent by the RFID label; an identification updating module: and sending an updated synchronization data frame comprising the hash transform identifier and the synchronization response check identifier.

In a fourth aspect, the present invention further discloses another synchronous communication device based on RFID, where the device is a device including RFID tags, and a plurality of RFID tags transmit tag response data in multiple channel time slots according to a currently received synchronous data frame sent by an RFID host, and receive synchronous response information sent by the RFID host, where the device includes the following modules: a mapping transformation module: the hash conversion identifier is used for receiving the hash conversion identifier contained in the synchronous data frame based on time synchronization, performing coding mapping conversion according to the hash conversion identifier and converting the label code of the hash conversion identifier into a hash label code; a time slot response module: the system is used for calculating corresponding channel time slot parameters according to the Hash label codes and sending label data frames in the appointed label response time slots; a verification judgment module: for identifying and judging the synchronization response check identifier in the received synchronization data frame: when the tag data frame has been received by the RFID host, the continued transmission of the tag data frame is immediately stopped.

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 of 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 field identification, improve the utilization efficiency of channel time slot resources, avoid group reading label response conflicts, and have obvious technical effects and benefits on low power consumption, quick awakening synchronization and high efficiency group reading label data frames of the active electronic label.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and 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 of a synchronous communication method based on RFID, that is, a flowchart of an RFID host, according to an embodiment of the present invention;

FIG. 2 is a flow chart of another RFID-based synchronous communication method, namely an RFID tag flow chart, disclosed in the embodiment of the present invention;

fig. 3 is a block diagram of an RFID-based synchronous communication device, that is, a block diagram of an RFID host device, according to an embodiment of the present invention;

FIG. 4 is a block diagram of another RFID-based synchronous communication device, namely an RFID tag device, according to the embodiment of the present invention;

FIG. 5 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. 6 is a time slot composition and a response signal timing chart in a synchronous response period of a tag response channel in the RFID tag group read response 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 present invention, and not all embodiments, and are intended to illustrate and not limit the present invention.

In a first embodiment, please refer to fig. 1, which is a flowchart of a synchronous communication method based on RFID disclosed in this embodiment, an RFID host group reads and receives tag response data sent by RFID tags in a plurality of target areas in a plurality of channel slots in a synchronous response period by sending a synchronous excitation signal, and specifically includes the following steps:

step S101, the RFID host sends a synchronous data frame contained in the synchronous excitation signal in a specified synchronous channel to enable the RFID label to obtain time synchronization;

step S102, the RFID host machine adjusts corresponding Hash transformation identification according to the segmented code domain distribution of the RFID label obtained by a detection and/or prediction mode at present, and the Hash transformation identification is used for code mapping transformation (Hash transformation) so that the RFID label code is converted into a Hash label code;

step S103, 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;

and step S104, the RFID host sends an updated synchronization data frame, and the synchronization data frame comprises the Hash transformation identifier and the synchronization response verification identifier.

The implementation of the above steps is further explained as follows:

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 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.

And the code domain distribution refers to the label probability distribution corresponding to different code domain intervals when the label code X is in a specified code domain limited range.

The label code X refers to the ID code of the RFID label or a code obtained by performing code mapping transformation on the ID code of the RFID label; 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 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.

In a second embodiment, please refer to fig. 2, which is a flowchart of a synchronous communication method based on RFID disclosed in this embodiment, where RFID tags in a plurality of target areas transmit tag response data in a plurality of channel slots in a synchronous response cycle according to a currently received synchronous data frame sent by an RFID host, and receive synchronous response information sent by the RFID host, the method specifically includes the following steps:

step S201, 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;

step S202, the RFID label calculates the corresponding channel time slot parameter according to the Hash label code, and sends a label data frame with the appointed time slot priority in the appointed label response time slot;

step S203, the RFID tag identifies and judges the synchronization response check identifier in the received synchronization data frame: when the tag data frame has been received by the RFID host, the continued transmission of the tag data frame is immediately stopped.

The implementation of the above steps is further explained as follows:

the hash bit segment, namely a hash sensitive bit segment, refers to a bit segment with higher hash degree contained in the label code;

the hash degree refers to the dispersion degree of different bit segment code values of a certain bit segment; the degree of hashing may be represented by calculating a frequency dispersion of different bit segment code values, the lower the frequency dispersion the higher the degree of hashing.

For example, if f (i) represents the frequency corresponding to the bit segment code value i, the frequency dispersion is represented by the discrete variance

Sr = SQRT(∑(f(i) - fa)2)/fa，

In the formula, fa is the average frequency of different bit segment code values, fa = Fn/N, where Fn is the total frequency, N is the number of the bit segment code values, and N = 2k, k > =1,k is the binary number of the bit segment; the total frequency Fn of the different bit segments contained by the tag code is the same.

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.

Example three, the implementation of the steps described above with reference to the flow charts of fig. 1 and 2 is further described as follows:

the synchronous data frame comprises a wireless synchronous identification, and the RFID tag obtains the time synchronization according to the synchronous identification; the RFID host sends the synchronous identification at least once in a 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 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 identification and performing synchronization time correction.

The synchronization mark is a wireless modulation pulse signal used for time synchronization; the synchronization identifier contains or follows a synchronization offset code, which is a code corresponding to a synchronization offset time, i.e., a synchronization offset.

Referring to fig. 5, 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 510, a synchronization channel 520, and a tag response channel 530, which is specifically described as follows:

synchronization channel 510: the RFID host sends a wake-up stimulus pulse signal 511 on the sync channel 510;

synchronization channel 520: the RFID host sends a series of sync frames 521 on the sync channel 520, where each sync frame contains one or more sync identifiers 5211, 5212 …; the synchronization marks 5211 and 5212 … are synchronization offsets (i.e., synchronization offset times) 5201 and 5202 …, respectively, with respect to a time difference between the start time of the synchronization response period 5301 (the synchronization phase time is set to 0);

tag reply channel 530: the RFID host transmits tag reply information within a series of synchronous reply cycles 5301 in the tag reply channel 530, including: sending a code clock signal 5311 in the code clock time slot 531 and a tag response data frame 5321 in the tag response time slot 532;

it should be noted that the synchronization channels 510 and 520 may be the same or different synchronization channels.

The synchronization mark is located before a synchronization data frame (with a certain gap or starting position); when a synchronization packet comprises a number of synchronization frames, it contains at least one synchronization mark. 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.

If the cooperative synchronization period Tc is expressed as a multiple with respect to the synchronization time step, one cooperative synchronization period Tc is divided into n synchronization shift time zones, and one synchronization shift time zone includes m synchronization time steps, the maximum synchronization shift is allowed to be m-1. For example, tc =64, n =4 offset time zones, each offset time zone including m =16 synchronization offsets, each RFID host can transmit 4 synchronization data frames at the 4 offset time zones at the maximum in one cooperative synchronization period.

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 wireless cooperative synchronization, namely cooperative time synchronization, means that a plurality of RFID hosts have the same cooperative synchronization period; the cooperative synchronization period refers to a synchronization period common to a plurality of RFID hosts, and synchronization marks sent by the RFID hosts have an associated consistent synchronization phase relationship.

The RFID tag obtains corresponding synchronous offset time according to the synchronous offset code; the synchronization offset time refers to the phase time of the current synchronization mark in one synchronization period.

When the synchronization tracking period at least comprises one or more synchronization response periods, skipping a plurality of default response periods; and the RFID label is in a low-power-consumption dormant state in the default response period, is awakened before the effective response period based on a synchronous timer, and detects and receives a synchronous excitation signal sent by the RFID host. After an effective response period, the RFID tag sets a synchronous timer corresponding to a plurality of default response periods and enters a low-power-consumption dormant state.

A plurality of RFID hosts in a collaborative synchronization state in a coverage area send collaborative consistent wireless synchronization identification: namely, sending wireless synchronous identification and synchronous data frames in synchronous offset time zones with different synchronous offsets; the RFID label carries out synchronization time correction according to the received wireless synchronization identification sent by any one RFID host, and can obtain the same and consistent synchronization response period and the contained label response channel time slot.

In a cooperative synchronization period, the wireless synchronization identifier sent by the RFID host comprises a series of synchronization offset identifiers, and when any synchronization offset identifier is received by the RFID tag, a subsequent consistent synchronization response period can be obtained through synchronization time correction.

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 carries out synchronous time correction according to the synchronous offset time corresponding to the synchronous offset code, and sends a label data frame in a specified channel time slot in a synchronous response period based on time synchronization.

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.

When the RFID host learns the wireless synchronization identification sent by other nearby cooperative RFID hosts 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 codes, the RFID host performs synchronization offset correction on the synchronization offset time of the wireless synchronization identification actually sent by the RFID host.

The RFID host takes the synchronization priority as a necessary condition whether to carry out the synchronization offset correction or not: and when the synchronization priority of the master RFID reader is lower than that of the adjacent cooperative RFID host, performing the synchronization offset correction. The priority for synchronization is given by one or a combination of the following ways: 1) specified by the system host, 2) according to the timing of the joining of the cooperative synchronization, and 3) pseudo-randomly specified.

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 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 tag receives the wake-up excitation pulse in the transient detection time slot of the RFID tag, the RFID tag is immediately awakened.

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 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 tag enters a coverage field area of an awakening excitation signal, preliminary initial awakening is obtained through transient detection, and the RFID tag is awakened gradually through detection time slot expansion so as to achieve a dynamic balance strategy for self-state power consumption and trigger response time; the coverage field may be a larger area of wireless coverage than the active burst read synchronous excitation.

The detection time slot expansion comprises increasing the duty ratio of the detection time slot (such as increasing the detection time slot and quickening the detection period) and/or improving the detection sensitivity (such as adjusting the high-frequency receiving front-end of an antenna); typically, the detection time slot expansion refers to increasing the detection time slot and/or speeding up the detection period.

After the RFID label is awakened, after a wireless synchronous identifier sent by the RFID host is received in a synchronous detection time slot, a channel code domain identifier following the synchronous identifier is continuously received; 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 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 also be included.

The code width index marks the code domain width of the code X; the code field is the value field of the index tag code X. The code width may refer to an absolute or relative code width, such as representing the relative code width by the complement of the code width ratio.

And the RFID label calculates corresponding channel time slot parameters based on self Hash label coding according to the channel code domain identification in the synchronous data frame.

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.

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 the 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 the response channel i in the current synchronous response period.

Referring to fig. 6, a time slot composition and a response signal timing chart in a synchronous response period 600 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 600 includes a code clock time slot 610 and a tag/asynchronous response time slot 620, which are described in detail as follows:

code clock time slot 610: a plurality of RFID tags pass through code time conversion, and code time pulses 6101, 6102 … with different code time pulse sending times (relative time is t) are sent in the code time pulse time slots 610;

tag/asynchronous reply slot 620: the RFID tag comprises a plurality of tag response time slots 621, 622, 623 and … X, and a certain RFID tag sends a tag data frame 6211 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 6212, 6213 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, the tag response frame 62X occupied with the highest timeslot priority (or found to be idle based on channel timeslot detection) may be selected, and the host asynchronous response frame 62X0 is sent.

Example four, the implementation of the steps described above with reference to the flowcharts of fig. 1 and 2 is further described as follows:

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 so as to obtain the code domain distribution of different label response channels by segmented time code conversion; the RFID host monitors the distribution quantity of the time slot activity of the code clock pulse signals of different channels simultaneously through wireless scanning detection, and the time code distribution detection is carried out.

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 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 pulse signals through wireless scanning detection, and obtains the corresponding code domain distribution through time code conversion.

And the RFID label calculates 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 to obtain the corresponding channel time slot parameter.

When the RFID tag is awakened in any awakening mode, continuously trying 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 low-power-consumption sleep-following state is immediately returned;

2) And if the RFID tag receives the synchronous identification in the synchronous detection time slot, the RFID tag is immediately and synchronously awakened to obtain time synchronization, synchronous time correction is carried out according to the synchronous offset code following the synchronous identification, and a synchronous response period is started according to the synchronous time of 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 synchronization marks.

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 RFID tag receives the synchronous excitation signal, and transmits a code clock signal through a code clock time slot in a synchronous response period based on time synchronization by section code clock conversion.

The label code X is a code that attempts to make the code widths of the 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 Code Time conversion (or C/T conversion) refers to the conversion of the tag Code from Code domain (Code domain) to 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.

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); firstly, the code pulse time t is converted into the channel label code X 'or the code domain interval affiliated to the channel label code X' in proportion.

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.

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.

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 RFID host monitors the distribution quantity of the time slot activity of the code clock pulse signals of different channels simultaneously through wireless scanning detection, and the time code distribution detection is carried out.

The code clock time slot is contained in a synchronous reply period; the code clock pulse signal is a preposed response signal sent by the RFID label in the code clock pulse time slot and is used for the time code distribution detection of the RFID host.

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.

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 the set group code identifier and/or the channel code domain identifier and sending a synchronous data frame containing the update 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.

The channel rated code width refers to the maximum code width allowed to be distributed in a channel in a synchronous response period; the channel rating code width may be a default value or a dynamic setting value included in the synchronization data frame.

If the RFID label does not receive the synchronous or asynchronous response check mark sent by the RFID host in a certain synchronous response period, the time slot detection can be carried out in the following label response time slot with low time slot priority, and the label data frame is sent again under the condition of judging 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.

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 check data frame for smooth response and control instruction to the specified label data frame through the asynchronous response.

When the RFID host receives a tag data frame sent by the RFID tag in a tag response channel, the RFID host sends a check data frame serving as an asynchronous response to one or more RFID tags in one of the following manners:

in the first mode, the RFID host immediately occupies the immediately following response time slot and sends the verification data frame with the highest time slot priority, and 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.

The asynchronous response refers to a tag data frame sent by one or more received RFID tags and a verification data frame sent as response information in a subsequent asynchronous response time slot by the RFID host within a synchronous response period of a certain tag response channel. Based on the current channel time slot occupation situation, the RFID host selects and adopts the following different time slot acquisition modes according to different asynchronous response requirements (such as verification, configuration and control), wherein the different time slot acquisition modes comprise: 1) Preempting acknowledgement slots based on high slot priority, 2) finding idle slots based on channel slot detection.

The RFID host implants corresponding synchronous response check marks in synchronous data frames after the RFID tags received in different tag response channels send the tag data frames in a synchronous response period; the group reading verification mark comprises a plurality of verification bit marks so as to reflect whether the label data frames of different label response channels and label response time slots thereof are received.

The RFID tag identifies the corresponding check position identification in the synchronous response check identification so as to judge whether the tag data frame sent before is received by the RFID host; the verification bit identification can reflect verification response 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.

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, the sending of the label response information and the label data frame thereof can be immediately stopped; and when the identification judges that the sent label data frame is not received by the RFID host, in a subsequent label response time slot of the same label response period, the time slot detection may still be performed with a low time slot priority, and the label data frame is sent again under a condition that the time slot is idle.

According to the received synchronous response check identification, when the RFID tag judges that the tag data frame sent by the RFID tag is received by the RFID host, the RFID tag can immediately stop sending the tag response information continuously; 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. 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.

The RFID label identifies and judges the received synchronous or asynchronous response information sent by the RFID host: when the label data frame is received by the RFID host, immediately stopping sending the label data frame; otherwise, the RFID label selects one of the following modes to resend the label response data frame according to the judgment of the current synchronous phase and asynchronous time slot: 1) In the subsequent label response time slot in the same synchronous response period, the label data frame is sent again with low time slot priority; 2) And waiting for the receiving RFID host to send a new synchronous data frame, and sending the label response information according to the updated channel time slot parameter in a new synchronous response period.

Before the RFID tag sends the response data frame according to the delay step length corresponding to the time slot priority, the channel time slot detection condition is exempted 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 size without exceeding the maximum allowed delay.

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 the designated 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.

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.

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 time delay step, and each time the time slot priority is reduced, one time delay step is increased. 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.

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 and the corresponding time slot priority of the current tag data frame 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.

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; before sending the label data frame, channel time slot detection is carried out, if and only if the return result of the time slot detection is that the channel time slot is idle, the sending is allowed, otherwise, the time slot priority is adjusted according to a mode of circularly increasing the priority in the next response time slot.

When the data signal state between a certain RFID tag and the RFID host fails to reach a predetermined index within a certain time, the RFID tag may transmit a help data frame including a help identifier within a certain idle channel time slot through channel time slot detection, so as to obtain a relay agent service.

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.

When a certain RFID label sends synchronous response data in a plurality of synchronous response periods, but does not receive response information from an RFID host, the RFID label can send the response information in one or the combination of the following ways through channel time slot detection in a certain idle channel time slot: 1) Sending a help data frame including a help identifier; 2) And transmitting the label data frames in a mode of increasing the radio frequency power.

The mode of the active RFID label becoming the relay agent node comprises one or the combination of the following modes:

in a first mode, the active RFID tag sends a tag data frame and receives response information, and according to a relay agent indication identifier sent by an RFID host, the active RFID tag becomes a relay agent node, and the relay agent indication identifier is included in the host response data frame;

in the second mode, when the signal received strength (RSSI) of the synchronous excitation signal received by the active RFID tag from the RFID host reaches a predetermined condition value, the active RFID tag becomes a relay agent node.

The condition value may be a predetermined value or an indication value included in the synchronization packet; the condition value may be associated with a self-capability status (e.g., remaining power) of the RFID tag, such as when the remaining power is insufficient, reducing or no longer actively relaying the proxy.

The hash transformation identifier is a wireless identifier reflecting hash bit segment parameters; the hash bit segment parameter is a hash bit segment code formed by bit selection codes or bit segment selection codes, and a mapping transformation parameter Pi for carrying out hash bit segment transformation according to the hash bit segment parameter comprises parameters of selection and combination modes of the hash bit segment; the hashed bit segment transform is a sensitive bit segment based hashability mapping transform on the tag code.

The hash bit segment conversion parameter is a hash bit segment code comprising one or a combination of the following modes: the method comprises the following steps of 1, 2, … and optional bit segment bits, wherein the bit sequence indicates the bit sequence number (or bit pointer) of the start bit of the bit segment in the label code, and the default value of the bit segment bits is omitted; mode two multi-selection code 1, multi-selection code 2, …, bit segment number of bits (optional), binary bit in the multi-selection code is 1.

In the actual development process, the multiple selection codes include bit selection codes or bit segment selection codes, such as: 1) Bit selection, 0xaaaa5555h indicates selection of the 2-byte even bits high and 2-byte odd bits low in the 4-byte tag code, 2) bit segmentation, e.g., 01010101b represents selection of the low half-byte of each byte in the 4-byte tag code; optionally, the hashed bit segment transform code further includes a bit segment sequence code, such as a starting bit sequence, a shift number of the selected bit segment; optionally, the hash bit segment transform code further comprises an opcode, such as a bitwise logical xor superposition of the selected bit segment with the non-selected bit segment.

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 converts the label code of the RFID label into a new Hash label code through the Hash bit segment conversion, 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 transform is a mapping transform that hashes a number of hash bit segments (hash-sensitive bit segments) included in the label code and recombines (orders, shifts, overlays); the hash bit segment transformations are associated with the current synchronization identification information such that when the hash tag codes of two or more RFID tags collide for one synchronization response period, then at the next synchronization response period, there will be no further consecutive collisions. 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 the cooperative host evaluates the probability weight of expected entering of a specified RFID host to cover the field according to the time and position frequency of the tracking object of the RFID tag in the hot list of the adjacent area, and calculates a refresh bit segment hash table based on the probability weight. The bit segment hash table comprises hash degree information of different sensitive bit segments in code domain distribution of the RFID tag tracking object.

The cooperative host is a peripheral RFID host and/or an upper host; the cooperating host may be a system server.

The code domain bit segment monitoring is to carry out continuous cooperative monitoring on the hash degree or frequency dispersion degree of different sensitive bit segments in the code domain distribution of the RFID label tracking object in the appointed target area and calculate a refresh bit segment hash table; the sensitive bit segment refers to a bit segment with higher hash degree (namely lower frequency dispersion); the cooperative monitoring refers to probability weight obtained by performing code domain distribution statistics on a designated coverage area according to the time position frequency of the current RFID label code by the cooperative host.

The RFID host evaluates and calculates the frequency dispersion of different sensitive bit segments in the code domain distribution according to a space-time sliding weighting method; and comparing the frequency dispersion, selecting a sensitive bit segment with relatively lower frequency dispersion, namely corresponding to a hash degree with relatively higher hash degree, and generating the corresponding hash bit segment conversion parameter such as a hash bit segment code. The space-time sliding weighting is a filtering calculation method for target variable acquisition for carrying out weighting limitation on a space-time range, and the method is suitable for filtering calculation of frequency and frequency dispersion of variable code values.

The RFID host calculates the hash degree or frequency dispersion of the sensitive bit segment in one or a combination mode;

firstly, weighting according to the space-time sliding, tracking and calculating the frequency f (i) corresponding to different bit segment code values, and evaluating and calculating the corresponding hash degree or frequency dispersion according to the frequency f (i);

directly weighting according to the space-time sliding in a second mode, and evaluating and calculating the current hash degree or frequency dispersion degree;

for example, according to the space-time sliding weighting, the frequency f (i, t) and the frequency dispersion Sr (t) corresponding to the current different bit segment code values are evaluated and calculated:

f(i,0) = ∑(W(t)*f(i,t))/∑W(t)，

Sr(0) = ∑(W(t)*Sr(t))/∑W(t)，

where Σ is the sum of the specified space-time range (e.g. within the time window T1 and the distance range R1), f (i, 0), sr (0) and Sr (T) respectively represent the frequency and frequency dispersion of the current (i.e. T = 0) bit segment code value, and W (T) is the relative weight of the previous T.

The space-time sliding weighting is a filtering calculation method for evaluating and calculating the acquisition of target variables by weighting according to space-time distance relative to the current time and the target position; for example, by adopting an iterative method of space-time exponential decay, the frequency f (i, t) and the frequency dispersion Sr (t) corresponding to the current different bit segment code values are calculated: f (i, 0) = (W (R) × f (i, 0) + W (t) × f (i, t))/(W (R) + W (t)) Sr (0) = (W (R) × Sr (0) + W (t) × Sr (t))/(W (R) + W (t)) in the formula, W (R) is a weight attenuation coefficient based on spatial exponential attenuation, reflecting the relative weight attenuation of the current (t = 0) target object at position R, where W (R) = Exp (-R/R1), and R1 is a given exponential attenuation distance; w (T) is a weight attenuation coefficient based on time exponential attenuation and reflects the relative weight attenuation of the target object at the previous T time, wherein W (T) = Exp (-T/T1), and T1 is a given time attenuation period.

An embodiment of the present invention further discloses a synchronous communication device based on RFID, please refer to fig. 3, which is an RFID host device, the RFID host group-reads and receives tag response data sent by RFID tags in a plurality of target areas in a plurality of channel time slots in a synchronous response period by sending a synchronous excitation signal, the RFID host device 300 includes: a synchronous excitation module 301, a code domain transformation module 302, a verification response module 303 and an identification update module 304, wherein:

the synchronous excitation module 301: the RFID tag is used for transmitting a synchronous data frame contained in the synchronous excitation signal on a specified synchronous channel so as to obtain time synchronization of the RFID tag;

code-domain transform module 302: the system is used for adjusting corresponding Hash transformation identifiers 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 code mapping transformation (Hash transformation) so as to convert the RFID label code into a Hash label code;

the verification response module 303: the synchronous response verification module is used for updating a synchronous response verification identifier in a synchronous data frame for synchronous response of the received label data frame sent by the RFID label in different label response time slots in a synchronous response period;

the identity update module 304: and sending an updated synchronization data frame comprising the hash transform identifier and the synchronization response check identifier.

An embodiment of the present invention further discloses a synchronous communication device based on RFID, please refer to fig. 4, where the device is a device including an RFID tag, that is, an RFID tag device, and RFID tags in a plurality of target areas transmit tag response data in a plurality of channel slots in a synchronous response cycle according to a currently received synchronous data frame sent by an RFID host, and receive synchronous response information sent by the RFID host, where the RFID tag device 400 includes: a mapping transformation module 401, a time slot response module 402 and a verification judgment module 403, wherein:

the mapping transformation module 401: the hash conversion identifier is used for receiving the hash conversion identifier contained in the synchronous data frame based on time synchronization, performing coding mapping conversion according to the hash conversion identifier, and converting the label code of the hash conversion identifier into a hash label code according to hash bit segment conversion;

the slot acknowledgement module 402: the system is used for calculating corresponding channel time slot parameters according to the Hash label codes and sending label data frames in the appointed label response time slots according to the appointed time slot priority;

the verification judgment module 403: for identifying and judging the synchronization response check identifier in the received synchronization data frame: when the tag data frame has been received by the RFID host, the continued transmission of the tag data frame is immediately stopped.

In practical implementation, the apparatus is a computer apparatus, and the processor executes computer instructions to implement the embodiment of the RFID-based synchronous communication apparatus disclosed in the foregoing.

Those skilled in the art will appreciate that all or part of the processes of 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 when executed, can include the processes of the embodiments of the methods described above.

For several terms referred to in the foregoing embodiments, further description is as follows:

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.

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).

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 defined by 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 therefrom are within the scope of the invention.

Claims (13)

1. A synchronous communication method based on RFID is characterized in that an RFID host computer sends synchronous excitation signals and group reads and receives label response data sent by a plurality of RFID labels, and the method specifically comprises the following steps:

the RFID host sends a synchronous data frame contained in the synchronous excitation signal in a synchronous channel to ensure that the RFID tag obtains time synchronization;

the RFID host adjusts corresponding Hash transformation identifiers according to the code domain distribution of the currently obtained RFID labels, and is used for converting the RFID label codes into Hash label codes;

the RFID host carries out synchronous response on the received label data frame sent by the RFID label by updating the synchronous response verification mark in the synchronous data frame;

and the RFID host sends an updated synchronous data frame, wherein the synchronous data frame comprises the Hash transformation identifier and the synchronous response verification identifier.

2. A synchronous communication method based on RFID is characterized in that a plurality of RFID labels send label response data in a plurality of channel time slots according to a currently received synchronous data frame sent by an RFID host, and receive synchronous response information sent by the RFID host, and specifically comprises the following steps:

the RFID label receives the Hash transformation identifier contained in the synchronous data frame based on time synchronization, performs code mapping transformation according to the Hash transformation identifier, and converts the label code of the RFID label into a Hash label code;

the RFID label calculates corresponding channel time slot parameters according to the Hash label code, and sends a label data frame in a designated label response time slot;

the RFID label identifies and judges the received synchronous response verification identification in the synchronous data frame: and when the tag data frame is received by the RFID host, stopping sending the tag data frame immediately.

3. An RFID-based synchronous communication method as claimed in claim 1 or 2, characterized in that the synchronous data frame contains a wireless synchronization identifier, from which the RFID tag obtains the time synchronization; the RFID host sends the synchronous identification at least once in a synchronous period;

the synchronization mark is a wireless modulation pulse signal used for time synchronization; the synchronization mark contains or follows a synchronization offset code, which is a code corresponding to the synchronization offset time.

4. The RFID-based synchronous communication method according to claim 1 or 2, wherein the RFID host learns the wireless synchronization marks transmitted by other nearby cooperative RFID hosts by detecting, and performs synchronization offset correction on the synchronization offset time of the wireless synchronization mark actually transmitted by itself according to the synchronization offset codes of both parties when the synchronization offset time of itself is not consistent with the synchronization offset code.

5. The synchronous communication method based on RFID as claimed in claim 1 or 2, wherein the RFID tag is kept in a low power consumption sleep state in a normal state of non-wake-up, and the RFID tag is woken up by receiving a wake-up excitation pulse signal through transient detection before obtaining the time synchronization;

and if the RFID tag fails to receive at least one wake-up excitation pulse in a micro time slot delta t of transient detection, immediately returning to the low-power-consumption sleep state.

6. The synchronous communication method based on RFID as claimed in claim 1 or 2, wherein after the RFID tag is awakened and after receiving the wireless synchronous identification sent by the RFID host in the synchronous detection time slot, the RFID tag continues to receive the channel code domain identification following the synchronous identification;

and the RFID label calculates corresponding channel time slot parameters based on the label code of the RFID label according to the channel code domain identification.

7. The synchronous communication method according to claim 1 or 2, wherein the RFID host performs time code distribution detection on the code clock pulse signal transmitted by the RFID tag to obtain the code domain distribution of different tag response channels by time code conversion;

the RFID host monitors the distribution quantity of the time slot activity of the code clock pulse signals of different channels simultaneously through wireless scanning detection, and the time code distribution detection is carried out.

8. The RFID-based synchronous communication method according to claim 1 or 2, wherein after the RFID tag is awakened, the RFID tag continues to attempt to receive the synchronization identifier in a designated synchronization detection time slot:

1) If the RFID label does not receive the synchronous identification in the appointed synchronous detection time slot, immediately returning to a low-power-consumption sleep state;

2) And if the RFID tag receives the synchronous identification in the synchronous detection time slot, immediately acquiring time synchronization, and starting a synchronous response cycle according to the synchronous time.

9. The synchronous communication method based on RFID as claimed in claim 1 or 2, wherein if the RFID tag does not receive the response verification identification sent by the RFID host in a synchronous response period, the time slot detection is performed in the following tag response time slot with low time slot priority, and the tag data frame is sent again under the condition that the time slot is judged to be idle.

10. The synchronous communication method based on RFID as claimed in claim 1 or 2, wherein the RFID tag performs channel time slot detection before transmitting its response data frame according to the delay step corresponding to the 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.

11. An RFID-based synchronous communication method according to claim 1 or 2, characterized in that the hash mapping flag is a wireless flag reflecting hash bit segment parameters; the hash bit segment parameter is a hash bit segment code composed of bit selection codes or bit segment selection codes, and a mapping transformation parameter Pi for carrying out the hash bit segment transformation comprises parameters of selection and combination modes of the hash bit segment; the hashed bit segment transform is a sensitive bit segment based hashability mapping transform on the tag code.

12. An RFID-based synchronous communication device, which is an RFID host device, wherein the RFID host device group-reads and receives tag response data transmitted by a plurality of RFID tags by transmitting a synchronous excitation signal, and the device comprises the following modules:

a synchronous excitation module: the RFID tag is used for transmitting a synchronous data frame contained in the synchronous excitation signal on a synchronous channel so as to obtain time synchronization of the RFID tag;

a code domain transformation module: the hash transformation identifier is used for adjusting the corresponding hash transformation identifier according to the code domain distribution of the RFID label obtained currently, and is used for converting the RFID label code into the hash label code;

the verification response module is used for: the synchronous response verification device is used for synchronously responding to a received tag data frame sent by the RFID tag by updating a synchronous response verification mark in the synchronous data frame;

an identification updating module: and the synchronous data frame is used for sending an updated synchronous data frame, and the synchronous data frame comprises the hash transformation identifier and the synchronous response verification identifier.

13. A synchronous communication device based on RFID is characterized in that the device is a device comprising RFID tags, a plurality of RFID tags transmit tag response data in a plurality of channel time slots according to a currently received synchronous data frame transmitted by an RFID host and receive synchronous response information transmitted by the RFID host, and the device comprises the following modules:

a mapping transformation module: the system comprises a synchronous data frame, a hash conversion identifier, a code mapping identifier and a hash label code, wherein the hash conversion identifier is used for receiving the hash conversion identifier contained in the synchronous data frame based on time synchronization, performing code mapping conversion according to the hash conversion identifier and converting the label code of the system into the hash label code;

a time slot response module: the system is used for calculating corresponding channel time slot parameters according to the Hash label codes and sending label data frames in the appointed label response time slots;

a verification judgment module: the system is used for identifying and judging the synchronization response verification identification in the received synchronization data frame: when the tag data frame is received by the RFID host, the tag data frame is immediately stopped from being continuously transmitted.

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