KR101221446B1 - Method and apparatus for controlling reader in radio frequency identification system - Google Patents

Abstract

In the existing RFID (Radio Frequency IDentification) system, there are many situations where the installed readers do not operate effectively due to the lack of a designated channel when several RFID readers are installed in one space. In many dense reader environments, it is essential to use a reader protocol that efficiently uses the specified channel, and reader collisions that reduce the tag recognition efficiency and recognition speed of the RFID system when the reader performs tag recognition. Problems may arise. Accordingly, in the present invention, the triggered leader occupies an empty channel through a channel scan and transmits a synchronization pulse to form a hierarchical structure among the readers. It receives time requests from the leaders and allocates time for each leader to operate so that the channels occupied can be used sequentially. As a result, in the present invention, reader collision can be minimized while efficiently using a given channel in a dense reader environment.

Description

Data collision prevention apparatus and method in radio frequency identification system {METHOD AND APPARATUS FOR CONTROLLING READER IN RADIO FREQUENCY IDENTIFICATION SYSTEM}

The present invention relates to an apparatus and method for preventing data collision in a radio frequency identification system suitable for minimizing collisions between readers in a radio frequency identification system, such as a radio frequency identification system.

Radio Frequency IDentification (RFID) is a field of an automatic recognition system such as a barcode, and can automatically recognize information of an object through a reader from a tag using a radio wave. Such RFID has been spotlighted as a technology to replace the existing bar code system, which has been degraded and easily damaged due to the development of low-cost tag technology due to the recent increase in semiconductor density and memory capacity. In particular, RFID is a non-contact technology that does not require line-of-sight to read tags, and at the same time has the advantage of being able to recognize large quantities of goods at high speed and to transmit large amounts of information. It is applied to a systematic and efficient logistics management system for recognizing and tracking objects in the logistics and manufacturing fields, and for inventory investigation.

However, the ongoing standardization of RFID technology has problems such as inefficient recognition of information on tagged articles due to tag collision or reader collision that may occur in an RFID system. In particular, it is difficult to industrialize the RFID system due to the reduction of the tag recognition efficiency and the recognition speed resulting from the tag collision or the reader collision in the RFID system. Therefore, if tag collision or reader collision, which is a factor that reduces tag information recognition rate and recognition speed, can be solved, RFID will be able to build an efficient system by replacing the current barcode.

In an RFID system, a tag collision refers to a collision occurring when multiple tags respond to a single reader query at the same time, and a reader collision refers to a collision caused by interference between adjacent readers in recognition of a tag. Among these, reader collisions can be divided into reader-to-reader collisions and multi-reader-to-tag collisions. Reader-to-reader collision is a phenomenon in which tags are not recognized because collision occurs between signals of readers using the same frequency when adjacent readers transmit signals to different tags using the same frequency. This can be solved by separating the frequency used between readers. Multiple reader-to-tag collisions occur when using passive tags. When two or more readers try to recognize the same tag group at the same time, the tags cannot distinguish between each reader's signal and are not recognized by any reader. It means the case. This can be solved by having each reader recognize the tag group sequentially with a time difference between the readers.

Currently, manufacturers of RFID systems produce tags and readers using standards based on low-cost passive tags proposed by EPC global Class 1 (hereinafter referred to as EPC Class 1), and many industries use them. Passive tags, unlike active tags that receive energy from batteries, do not contain batteries, so they send information back to the reader using back scattering. As such, passive tags with a simple structure excluding batteries can be mass-produced at a low price, which is a component of an RFID system suitable for use in large-scale logistics and manufacturing.

EPC Class 1 proposes a technique based on dynamic framed slotted ALOHA (DFSA) and frequency hopping spread spectrum (FHSS) as a method for resolving tag collisions and reader collisions, which are problematic in the above-mentioned RFID system. Among these, FHSS is a technology using frequency hopping to prevent reader collision based on frequency division multiple access (FDMA). However, FHSS, which is a standard in EPC Class 1, is not a suitable method for resolving reader-to-reader collisions because the low-cost passive tag used does not have the characteristic of distinguishing reader frequency. In addition, there is no protocol to control the behavior between the readers, which does not resolve multiple reader-to-tag conflicts. Therefore, in order to resolve the reader conflict, it is necessary to complement the technology to solve the reader-to-leader conflict and the multiple reader-to-tag collision together with the FHSS proposed in EPC Class 1.

Therefore, in the embodiment of the present invention, collisions between readers in a radio frequency identification system, such as a radio frequency identification (RFID) system, are minimized to improve tag recognition rate, and at the same time in a dense reader environment. We propose a data collision avoidance technique in a radio frequency identification system that can efficiently use a given channel.

An apparatus for preventing data collision in a radio frequency identification system for preventing data collision between readers in a dense reader environment according to an embodiment of the present invention, confirms whether a channel is used in the dense reader environment, If the channel is not in use, the data collision prevention device is set as a master reader by occupying the frequency band of the one channel, and after being set as the master reader, the control unit transmits a synchronization pulse to adjacent readers around the master reader. A data collision prevention unit for synchronizing time between readers in the dense reader environment after establishing a vertical structure with the adjacent readers, and a synchronization pulse generation unit generating the synchronization pulses under the control of the data collision prevention unit; The sync pulse generated by the sync pulse generator is transmitted to the adjacent readers, or The neighbor information may include a transceiver for transmitting and receiving with the reader.

Here, the data collision prevention unit, when the data collision prevention device is set as the master leader, may set the adjacent readers as slave readers, respectively.

The data collision prevention unit may synchronize time so that the master reader and the slave reader do not overlap each other.

The time information may include at least one of time request information, time allocation information, time return request information, time return permission information, or operation time notification information.

In addition, the data collision prevention unit may receive the time request information from one slave reader that requires operation among the slave readers.

The data collision prevention unit may transmit the time allocation information according to the time request information to the one slave reader.

The data collision prevention unit may further include the time return permission information and the operation time notification information according to the time return request information received when the tag recognition operation of the one slave reader is completed according to the time allocation information. Can be sent to.

In the method of preventing data collision in a radio frequency identification system according to an exemplary embodiment of the present invention, the master reader transmits a synchronization pulse to a plurality of slave readers adjacent to the master leader, thereby preventing operation of the plurality of slave readers. Initiating and forming a hierarchical structure among leaders in the dense leader environment, receiving and allowing time requests through communication with the plurality of slave readers, and tag recognition among the plurality of slave leaders The method may include receiving and accepting a request for returning a completed slave reader time, and notifying, by the master reader, a transmission time to the slave reader on which the tag recognition is completed.

Here, the sync pulse may be transmitted for a time that can be recognized by the leaders in the dense reader environment.

The forming of the hierarchical structure may include synchronizing a time between the master leader and the plurality of slave readers at the end of the transmission of the sync pulse.

In the method of preventing data collision in a radio frequency identification system according to an embodiment of the present invention, the slave reader receiving the sync pulse forms a hierarchical structure with the master leader and receives the sync pulse from the slave reader. It may include the step of checking the end time by continuously checking, and synchronizing the time with the master leader according to the end time determination result.

Here, in the synchronizing process, if the slave reader is triggered without starting the operation, the slave reader is assigned an operation time of the first frame through communication with the master reader, and Receiving a time allocation request by the master reader through time allocation information received from the master leader, receiving time from the master leader to operate the slave reader during a second frame; The slave reader may have a waiting time until the end of the second frame after the tag recognition operation.

In addition, the synchronizing may include requesting a time return to the master reader when the slave reader finishes tag recognition, and ending a tag recognition operation when time return permission information is received from the master reader. It may include.

According to the present invention, a plurality of adjacent readers are formed while forming a hierarchical structure of readers in a range in which a collision can occur in a radio frequency identification system such as an RFID system and allocating time under the control of a master reader. By preventing the operation of the tag, reader collision can be prevented to increase the tag recognition rate. In addition, since a single channel may be operated by a plurality of readers, an effective operation may be performed even in a dense reader environment.

1 is a schematic block diagram of a radio frequency identification system for implementing an apparatus for preventing data collision according to an embodiment of the present invention;
2 is a block diagram illustrating an apparatus for preventing data collision in a radio frequency identification system according to an embodiment of the present invention;
3 is a flowchart illustrating a data collision prevention process in a radio frequency identification system according to an embodiment of the present invention;
4 is a flowchart illustrating an exemplary operation of a master reader in a data collision prevention method according to an embodiment of the present invention;
5 is a flowchart illustrating an example of an operation of a slave reader in a data collision prevention method according to an embodiment of the present invention;
6A and 6B exemplarily illustrate a slot structure of three readers for explaining a data collision prevention method according to an embodiment of the present invention.

Advantages and features of the present invention, and methods of achieving the same will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like numbers refer to like elements throughout.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions in the embodiments of the present invention, which may vary depending on the intention of the user, the intention or the custom of the operator. Therefore, the definition should be based on the contents throughout this specification.

Each block of the accompanying block diagrams and combinations of steps of the flowchart may be performed by computer program instructions. These computer program instructions may be loaded into a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus so that the instructions, which may be executed by a processor of a computer or other programmable data processing apparatus, And means for performing the functions described in each step are created. These computer program instructions may be stored in a computer usable or computer readable memory that can be directed to a computer or other programmable data processing equipment to implement functionality in a particular manner, and thus the computer usable or computer readable memory. It is also possible for the instructions stored in to produce an article of manufacture containing instruction means for performing the functions described in each block or flowchart of each step of the block diagram. Computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operating steps may be performed on the computer or other programmable data processing equipment to create a computer-implemented process to create a computer or other programmable data. Instructions that perform processing equipment may also provide steps for performing the functions described in each block of the block diagram and in each step of the flowchart.

Also, each block or each step may represent a module, segment, or portion of code that includes one or more executable instructions for executing the specified logical function (s). It should also be noted that in some alternative embodiments, the functions mentioned in blocks or steps may occur out of order. For example, two blocks or steps shown in succession may in fact be performed substantially concurrently, or the blocks or steps may sometimes be performed in reverse order according to the corresponding function.

Before the operation, the reader determines whether the channel is used through channel scanning, and transmits a synchronization pulse to form an up-and-down structure with adjacent readers and synchronize time synchronization.

The upper reader, the master reader, controls the readers so that the operation does not overlap with the lower reader, the slave reader. The lower reader, which requires the operation, is assigned a transmission time through communication with the upper reader, and performs a tag recognition operation through the predetermined time. Slave reader who finished tag recognition notifies master leader and returns assigned time and finishes operation.

This action prevents readers from colliding with tags by preventing readers from simultaneously identifying tags by grouping leaders in a hierarchy where collisions can occur and operating them one by one. Read rate and recognition speed can be improved.

The present invention aims to improve tag recognition rate by minimizing collisions between readers in a radio frequency identification system, such as a radio frequency identification system (RFID), and to efficiently use a given channel in a dense reader environment. From the spirit, the object of the present invention can be easily achieved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic configuration diagram of a radio frequency identification system, for example, an RFID system, which may be applied to an embodiment of the present invention, and may include an RFID reader group 100 and an RFID tag group 200.

The RFID reader group 100 may be composed of a plurality of readers 100/1 to 100 / N. The RFID reader group 100 may determine whether to use a channel through channel scanning prior to a tag recognition operation, and determine whether the RFID reader group 100 is adjacent to the adjacent readers. By establishing a vertical structure relationship (master / slave relationship), it is possible to play a role of matching time synchronization in the RFID reader group 100.

The RFID reader group 100 can improve tag recognition rate by minimizing collision between readers according to an embodiment of the present invention, and at the same time can efficiently use a given channel in a dense reader environment. .

The RFID tag group 200 may be composed of a plurality of tags 200/1 to 200 / N, and each of the tags 200/1 to 200 / N stores information on a history of a predetermined object. In addition, the stored information may be transmitted back to the RFID reader group 100 using the RF signal provided by the RFID reader group 100 as energy.

FIG. 2 is a detailed block diagram of an apparatus for preventing data collision in a radio frequency identification system according to an exemplary embodiment of the present invention, for example, reader 1 (100/1), which is an arbitrary reader in the RFID reader group 100 of FIG. .

As shown in FIG. 2, the data collision prevention apparatus in the radio frequency identification system according to the embodiment of the present invention includes a data collision prevention unit 102, a sync pulse generating unit 104, a transceiver unit 106, and a tag. The recognition unit 108 may be included.

First, the data collision prevention unit 102 determines whether a channel is in use by another system by determining whether a channel is used through channel scanning prior to a tag recognition operation according to an exemplary embodiment of the present invention, and determines that the corresponding channel is different. If it is not used by the system, it occupies the frequency band of the corresponding channel, sets itself as the master leader, and after setting as the master leader, controls the sync pulse generator 104 to transmit the sync pulse to other readers adjacent to the leader group. After establishing an up-and-down structure (master / slave relationship) with neighboring readers in the 100, it may serve to adjust time synchronization within the RFID reader group 100.

For example, the data collision prevention unit 102 sets reader 1 (100/1), which is its leader, as the master leader, and readers 2 (100/2) to reader N (100 / N) as the slave leader, which are lower readers. Will be set. However, setting the data collision prevention apparatus of FIG. 2 as a master leader and setting the remaining readers 100/2 to 100 / N as slave readers is merely an example of an exemplary embodiment of the present invention, and a slave may be used as needed. It will be appreciated that any of the leaders 100/2-100 / N may be set as the master leader.

Here, the data collision prevention unit 102, in accordance with an embodiment of the present invention, in order to prevent the leader 1 (100/1), which is the master leader, from overlapping with the slave readers (100/2 to 100 / N). Slave readers 100/2 to 100 / N may be controlled as follows.

First, the data collision avoidance unit 102 in the reader 1 (100/1) transmits a synchronization pulse to the slave reader, for example, the reader 2 (100/2), which needs to operate to synchronize time with the reader 2 (100/2). To form a hierarchy.

In detail, the data collision prevention unit 102 may receive time request information from the leader 2 (100/2) and transmit time allocation information according to the time request information to the reader 2 (100/2).

According to the time allocation information, the reader 2 (100/2) may perform a tag recognition operation. When the tag recognition operation of the reader 2 (100/2) is completed, the time return request information is sent to the transceiver unit 106. It may be received by the reader 1 (100/1).

According to the time return request information, the data collision prevention unit 102 in the reader 1 (100/1) can transmit the time return permission information and the operation time notification information to the reader 2 (100/2), and tags of all readers. The channel occupancy can be completed when the recognition operation is completed.

The sync pulse generator 104 may generate an arbitrary sync pulse under the control of the data collision prevention unit 102, and the generated sync pulses may be adjacent to slave readers, for example, through the transceiver 106. It may be transmitted to the reader 2 (100/2).

The transmitter / receiver 106 transmits the above-described sync pulse generated by the sync pulse generator 104 to the slave readers, or time information according to an embodiment of the present invention, for example, time request information, time allocation information, Time return request information, time return permission information, operation time notification information, and the like can be transmitted and received.

The tag recognition unit 108 may recognize tag information stored in tags around the reader 1 (100/1), for example, tag 1 (200/1) to tag N (200 / N), and recognize the tag information. It may serve to transfer to the data collision prevention unit 102.

Hereinafter, with reference to the above-described configuration, with reference to the flowchart of Figures 3 to 5 attached to the data collision prevention method in a radio frequency identification system according to an embodiment of the present invention will be described in detail. 3 to 5, the master leader will be exemplified as leader 1 (100/1).

First, FIG. 3 is a flowchart illustrating a data collision prevention method in a radio frequency identification system according to an embodiment of the present invention, specifically, a data collision prevention technique of the leader group 100 of FIG. 1.

As shown in FIG. 3, when the operations of the leaders 100/1 to 100 / N in the leader group 100 are started, the respective readers 100/1 to 100 / N sense their own frequency bands. It may be (S100). Through the detection of the frequency band, it is possible to check the operation of adjacent readers and the occupancy state of the channel.

Here, the frequency band detection and the channel occupancy state may be determined by different power thresholds. By determining the power thresholds, at least two or more readers may be formed by forming a hierarchical structure between readers in a collision occurrence range. It is possible to prevent collision between readers as they operate simultaneously.

Therefore, the power threshold for determining whether or not adjacent leaders are operated may be determined to include a level of leaders that cause a collision during simultaneous operation. The threshold of the power pulse for determining the occupancy state of the channel needs to be checked to a lower power range than the threshold for determining whether the adjacent reader operates.

Through this operation, an empty channel can be identified in advance, and a channel preempted by another RFID reader or another system can be prevented from being selected.

If the adjacent reader is in operation, a pulse having a power higher than the power threshold may be received by the leader in operation, whereby the leader may start to operate as a slave reader (S102) (S104).

If the corresponding reader is triggered in the state in which no power pulse is received (S106), it is determined that there is no operation of an adjacent reader, and occupies an empty frequency channel and the corresponding leader is the master reader (100 /). Operation to 1) can be started (S108) (S110).

When the operation of the master leader 100/1 or the operation of the slave leader ends, it may be determined whether tag recognition of all the leaders in the leader group 100 is completed. If there is a leader that requires tag recognition in the leader group 100, the feedback (feedback) to step (S100), and if the tag recognition of all the leaders in the leader group 100 is completed (S112). ).

FIG. 4 is a flowchart illustrating an exemplary operation of a master reader 100/1 preempting a specific frequency band among readers in a data collision prevention method according to an exemplary embodiment of the present invention.

First, the master leader 100/1 may transmit a synchronization pulse to neighboring leaders including a slave leader, thereby informing the neighboring leaders of the start of operation and forming a hierarchical structure between the leaders (S200).

In this case, the synchronization pulse may be transmitted for a sufficient time to recognize other readers, and the time between the master reader 100/1 and the slave leader may be synchronized at the time when the transmission of the synchronization pulse is finished.

In the first frame, the tag recognition operation of the master reader 100/1 may be immediately started after the synchronization pulse is transmitted in an exception situation. After the tag recognition of the predetermined time is completed, the master reader 100/1 may transmit a synchronization pulse to synchronize time with the slave reader.

Subsequently, the master leader 100/1 may communicate with the slave leader to determine an operation in the next frame, and receive time request information from a previously triggered slave leader (S202).

The slave reader transmitting the time request information can be distinguished from each reader by transmitting its unique ID to the master leader, and the master reader 100/1 receiving the time request information includes the unique ID of the requested slave leader. In operation S204, time allocation information may be transmitted to the slave reader.

If the time request information arrived from the slave leader has a conflict or is not transmitted correctly to the master leader 100/1, the master leader 100/1 does not accept the request, and the slave leader re-enters the next frame. The request will participate in the transmission. When the slave reader that is operating returns all time after all tag recognition is completed, the master reader 100/1 may receive time return request information from the slave reader (S206).

Thereafter, the master leader 100/1 may transmit time return permission information to the slave leader to allow a time return request (S208).

The time request information and the time return request information of the slave reader may be composed of a plurality of detailed slots, and the slave leader may transmit its ID to the master reader 100/1 through one randomly selected slot. have.

Through the above-described operations, the leader information required for the operation in the next frame may be collected by the master reader 100/1. Based on the collected information, the master reader 100/1 may include a time slot in which the slave reader operates. Information can be notified to the slave leader.

In order to inform the order of operation in the frame, the master reader 100/1 stores the IDs of all the readers, including their own IDs, in a queue-type memory (not shown). The ID can be taken out of the queue one by one to calculate the time to inform the slave reader of the time slot information to start transmission in the next frame (S210).

In the next frame, each leader may be sequentially operated in the order in which the master leader 100/1 is notified.

If the operation of all the readers who form the hierarchical structure in the leader group 100 ends (S212), the leader 1 (100/1) may terminate the role as the master leader.

On the other hand, if the operation of the leader remains, it is possible to return to the initial state and repeat the series of operations (S214) (S216) (S218).

These actions prevent reader collisions because adjacent readers share the channel occupied by the master leader and recognize the tag by occupying the channel through different times under the control of the master leader. Since the channel is shared, the channel can be used efficiently in a dense reader environment that lacks the channel.

5 is a flowchart illustrating an exemplary operation of a slave reader in a data collision prevention method according to an embodiment of the present invention. In the description of FIG. 5, the slave leader will be exemplified as leader 2 (100/2) of FIG. 1.

First, the slave reader 100/2 receiving the synchronization pulse may form a hierarchical structure with the master leader 100/1 that has transmitted the synchronization pulse, and may start an operation as the slave reader 100/2 (S300). .

The slave reader 100/2 continuously checks the received synchronization pulses to determine the end point, and synchronizes time with the master reader 100/1 according to the result.

Subsequently, since the tag recognition time of the master reader 100/1 is continued, the slave reader 100/2 may have a preset waiting time (S302).

If the slave reader 100/2 is triggered in a state in which the operation has not started (S304) (S306), time can be allocated through communication with the master reader 100/1, for example, the master reader 100 /. In accordance with the time allocation request time of 1), the unique ID may be transmitted to the master leader 100/1 to request time allocation (S308).

If the time allocation request is accepted by the master leader 100/1, time usage is allowed through the time allocation information received from the master leader 100/1 (S310), and the time for which the user operates during the next frame is determined. It can be received from the master reader (100/1) (S312).

Then, the slave leader 100/2 may have a waiting time as long as the time allocated to it in the next frame (S314), and may start a tag recognition operation at the time allocated to it (S316).

Subsequently, the slave leader 100/2 may have a waiting time until the end of the frame (collision avoidance dimension) (S318). When the waiting time ends, the slave leader 100/2 may repeat the above-described processes in the next frame.

On the other hand, when the slave reader (100/2) is finished tag recognition (S320), the request to return the time to the master reader (100/1) (S322), through the time return request, return the allocated time can do.

The slave reader 100/2 transmits its unique ID to the master reader 100/1 for the time return request time of the master reader 100/1, and requests for time return, and from the master reader 100/1, When the time return permission information is received (S324), all tag recognition is completed and the operation ends.

6A and 6B exemplarily illustrate slot structures of three readers for explaining a data collision prevention method according to an embodiment of the present invention.

6A and 6B show that when three readers are adjacent to each other and one reader is determined to be the master leader and transmits a pulse signal, the remaining readers receive a pulse of power sufficiently larger than the power threshold and receive a slave leader of the master leader. Illustrate the situation that is formed.

Three adjacent readers (referred to as R1, R2, and R3, respectively) can detect available frequency bands.

R1 detects the frequency band and triggers to select one empty channel to finally check whether the frequency channel is available. The empty channel can be known in advance by detecting a frequency band.

If the selected channel is not occupied by another reader or another device, a sync pulse signal is transmitted to the neighboring reader to form a hierarchical structure and time synchronization with the neighboring leader.

R2 and R3 receive a sync pulse signal of R1 in the operation of sensing a frequency band, and become a slave leader of R1 to synchronize time with R1.

The R1 occupying the channel starts the tag recognition operation for one hour of the frame and stops the transmission if the predetermined time passes, and starts communicating with the lower layer readers.

R2 triggered during the time when the master reader R1 recognizes a tag may request time to R1 through a time request time during communication with R1, and R1 may allow R2 to use the time.

When the communication time between readers is over, tag recognition starts in order.

When all the readers are finished, one frame ends, and communication time between readers starts again, and the third frame may begin.

At this time, triggered R3 requests time to R1 and R1 allocates time to R3.

First of all, after the operation, the R2 requests time return during the communication time between the readers and when the master leader allows the return, the tag recognition ends and ends.

In this way, when all the readers are under the control of the master leader, the master leader ends the channel occupation and returns to the channel scan process.

On the other hand, if the reader disposed at a position sufficiently far from R1, R2, and R3 during the same time is triggered, the reader is not a slave leader of R1 because the pulse signal transmitted by R1 is received at a power smaller than the predetermined power range. If such a reader is triggered, reader conflicts can be avoided by occupying other frequency channels not used by R1, R2, and R3.

According to an embodiment of the present invention as described above, adjacent readers are operated while forming a hierarchical structure of readers within a range in which a collision can occur in a radio frequency identification system, such as an RFID system, and allocating time under the control of a master reader. By preventing this, reader collision can be prevented and the tag recognition rate can be increased. In addition, since a single channel can be operated by a plurality of readers, effective operation is possible even in a dense reader environment.

102: data collision prevention unit
104: sync pulse generator
106: transceiver
108: tag recognition unit

Claims (13)

An apparatus for preventing data collision in a radio frequency identification system for preventing data collision between readers in a dense reader environment,
Check whether the channel is used in the dense reader environment, and if one channel is not the channel being used, set the data collision prevention device as a master reader by occupying the frequency band of the one channel, and set the master reader and then the master. A data collision avoidance unit configured to control the transmission of synchronization pulses to neighboring readers around the reader to establish a hierarchical structure with the neighboring readers, and then synchronize time between the readers in the dense reader environment;
A sync pulse generator for generating the sync pulse under the control of the data collision prevention unit;
And a transceiver configured to transmit the sync pulse generated by the sync pulse generator to the neighbor readers, or to transmit and receive time information with the neighbor readers.
Data collision prevention device in radio frequency identification system.
The method of claim 1,
The data collision prevention unit, when the data collision prevention device is set as the master leader, respectively set the neighboring readers as slave readers.
Data collision prevention device in radio frequency identification system.
The method of claim 2,
The data collision prevention unit may synchronize time so that the master reader and the slave reader do not overlap each other.
Data collision prevention device in radio frequency identification system.
The method of claim 2,
The time information includes at least one of time request information, time allocation information, time return request information, time return permission information, or operation time notification information.
Data collision prevention device in radio frequency identification system.
The method of claim 4, wherein
The data collision prevention unit may receive the time request information from one slave reader that needs operation among the slave readers.
Data collision prevention device in radio frequency identification system. The method of claim 4, wherein
The data collision prevention unit transmits the time allocation information according to the time request information to the one slave reader.
Data collision prevention device in radio frequency identification system.
The method of claim 4, wherein
The data collision prevention unit transmits the time return permission information and the operation time notification information to the one slave reader according to the time return request information received when the tag recognition operation of the one slave reader is completed according to the time allocation information. doing
Data collision prevention device in radio frequency identification system.
In the method of preventing data collision in a radio frequency identification system that checks whether a channel is used in a dense reader environment, and if one channel is not a channel being occupied, the channel occupies the frequency band of the one channel.
Sending a synchronization pulse to a plurality of slave readers adjacent to the master leader, thereby informing the plurality of slave leaders to start operation and forming a hierarchical structure among the leaders in the dense leader environment;
Receiving and allowing time request through communication with the plurality of slave leaders;
Receiving and allowing a request for returning a time of a slave reader in which a tag recognition is completed among the plurality of slave readers;
And notifying, by the master reader, the transmission time to the slave reader of which the tag recognition is completed.
Data collision prevention method in radio frequency identification system.
The method of claim 8,
The sync pulse is transmitted for a time recognizable by the leaders in the dense reader environment.
Data collision prevention method in radio frequency identification system.
The method of claim 8,
Forming the hierarchical structure,
And synchronizing the time between the master leader and the plurality of slave readers at the end of the transmission of the sync pulse.
Data collision prevention method in radio frequency identification system.
Check whether the channel is used in the dense reader environment, and if one channel is not in use, it is set as the master leader by occupying the frequency band of the one channel, and the master leader is synchronized to the slave reader adjacent to the master leader. In the data collision prevention method of the radio frequency identification system for transmitting a,
Forming a hierarchical structure with the master leader by the slave leader receiving the sync pulse;
And checking a time point at which the slave reader is terminated by continuously checking the received synchronization pulses, and synchronizing the time with the master reader according to the termination time determination result.
Data collision prevention method in radio frequency identification system.
The method of claim 11,
The synchronization process,
If the slave reader is triggered in a state that does not start the operation, the slave reader is assigned an operation time of the first frame through communication with the master reader,
When the time allocation request is permitted by the master leader, the slave reader is allowed to use time through time allocation information received from the master leader, and receives a time from the master leader to operate the slave reader during a second frame. Process,
The slave reader has a waiting time until the end of the second frame after the tag recognition operation;
Data collision prevention method in radio frequency identification system.
The method of claim 11,
The synchronization process,
Requesting return of the time to the master leader when the slave leader finishes tag recognition;
When the time return permission information is received from the master leader, including the step of ending a tag recognition operation.
Data collision prevention method in radio frequency identification system.

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