WO2014113988A1 - Procédé anti-collision et dispositif pour lecteur multiple - Google Patents

Procédé anti-collision et dispositif pour lecteur multiple Download PDF

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Publication number
WO2014113988A1
WO2014113988A1 PCT/CN2013/071020 CN2013071020W WO2014113988A1 WO 2014113988 A1 WO2014113988 A1 WO 2014113988A1 CN 2013071020 W CN2013071020 W CN 2013071020W WO 2014113988 A1 WO2014113988 A1 WO 2014113988A1
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channel
reader
list
tag
available
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PCT/CN2013/071020
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English (en)
Chinese (zh)
Inventor
王宏刚
刘会敏
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深圳市中兴长天信息技术有限公司
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Publication of WO2014113988A1 publication Critical patent/WO2014113988A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/16—Discovering, processing access restriction or access information

Definitions

  • the present invention relates to the field of wireless communications, and more particularly to a method and apparatus for multi-reader collision avoidance.
  • Radio Frequency Identification is a non-contact automatic identification technology that automatically recognizes target objects and acquires relevant data through radio frequency signals. The identification work can be performed in various harsh environments without manual intervention. Radio frequency identification technology recognizes high-speed moving objects and recognizes multiple tags at the same time, making operation quick and easy.
  • the basic working principle of RFID technology is as follows: The reader sends a radio frequency signal to the tag in the electromagnetic field coverage area. After receiving the RF signal from the reader, the tag transmits the product information stored in the chip by the energy obtained by the induced current ( For passive tags or passive tags), or use the energy provided by the battery carried by the tag to send a signal of a certain frequency (for active tags or active tags); active tags can actively send RF signals to the reader.
  • the reader After reading and decoding the information, the reader sends it to the application system for data processing to identify and collect data from the field.
  • the above process is also called a reader inventory tag or an identification tag, and its identification method or inventory method is also a communication method or an air interface standard in terms of technical specifications.
  • radio frequency identification systems use different communication (identification) methods depending on the specific application and technical requirements.
  • the international standards ISO 18000-6 and ISO 18000-7 respectively specify communication methods for passive radio frequency identification systems operating at 900 MHz and communication methods for active radio frequency identification systems operating at 433 MHz.
  • the active radio frequency identification system defined by the GJB 7377.2-2011 military radio frequency identification air interface protocol operates in the 2.45 GHz band.
  • a radio frequency identification system consists of a reader and a plurality of tags.
  • the reader and the tag specified in ISO 18000-6 type C communicate with each other by: the reader initiates an inventory cycle by sending a query command (Query). After receiving the query command, the tag randomly selects an integer from 0 to 2 Q -1 according to the command parameter Q. By default, 0 is sent.
  • the transmitted tag carries a 16-bit random number RN16 as a temporary identity ID. If the transmission is successful, the ID is used as the identity information to complete the authentication between the reader and the tag. After the authentication is successful, the reader sends a point-to-point command to read the information carried by the tag. For example: EPC (Electronic Product Code), TID (Tag identifier, Tag Identification Number), etc.
  • the reader can complete the write operation by command. No successful label was sent, waiting for the next query command (Query) to respond again.
  • the method of communication between the reader and the tag specified in ISO 18000-7 is:
  • the reader sends a specific waveform as a wake-up signal to wake up the sleeping tag. After the tag is woken up, it waits to receive a collection command (Collection) sent by the reader. After receiving the collection command, the tag randomly selects a time slice to reply to its own information in a time window according to the parameter (that is, selects a slot in a frame of the framing time slot ALOHA to transmit its own information). After receiving a time window (or a frame), the reader confirms the successfully transmitted label and further reads the label information, such as UDB (Universal Data Block), and sends a sleep command after the read succeeds. After receiving the sleep command, the tag enters the sleep state and cannot respond to subsequent collection commands until the next time it is woken up. If the label is not successfully sent, the time slice is reselected and sent in the subsequent time window.
  • UDB Universal Data Block
  • the reader and tag communication method specified in GJB 7377.2-2011 is:
  • the tag is usually in a dormant state or periodically sleep/wake state. Before the reader communicates with the tag, the tag must be woken up by an external wake-up system or the tag is guaranteed.
  • the communication process between the reader and the tag is divided into a wake-up period, an access period, a collection period, and a session period.
  • the reader sends an access command to the awake tag, and accesses all the awake tags according to a preset anti-collision protocol, and assigns each of the accessed tags to indicate that they are in the collection time slot.
  • the slot number is collected by the slot position; after the reader issues the collect command, the tag transmits the data required by the collection command (collection command) to the reader according to the slot position of the collection slot determined by the received slot number received.
  • the reader communicates point-to-point with the tag, after which the reader sends a sleep command to put the tag to sleep.
  • the tag in the above active radio frequency identification system, the tag usually needs to be in a dormant state outside of the unclearing or identification process to save the tag energy and thereby obtain a longer service life. Therefore, before the tag is identified, a wake-up signal of a certain length of time is usually sent to activate the tag and open the tag communication module.
  • the inventory process is usually initiated by the reader and a predetermined anti-collision protocol is executed to achieve the multi-tag identification process.
  • the wake-up process is usually not required, but the reader sends commands directly to initiate an inventory process.
  • existing RFID systems are usually operated in a single reader environment. In this case, there is only one reader in an RFID system or only one RFID system is working in the working area of the reader. In this way, a single reader is the only initiating master in the work area, easy to manage and coexist with the environment system.
  • a large RFID application system may have more than one reader or an RFID application site.
  • reader collision The interference generated when the tags in the area receive signals from different readers at the same time, or the interference generated when multiple readers in the coverage area transmit or receive signals, etc., is called reader collision. This is likely to cause a reader's inventory process to not work properly due to interference from other readers working at the same frequency.
  • the technical problem to be solved by the present invention is to provide a multi-reader anti-collision method and apparatus for avoiding multi-reader collisions in view of the above-mentioned defects of multi-reader collision in the prior art.
  • the technical solution adopted by the present invention to solve the technical problem thereof is: constructing a multi-reader anti-collision method, comprising the following steps:
  • the reader obtains a list of available channels; the list of available channels includes channel information for each available channel;
  • the reader selects the first channel from the list of available channels as a channel to be operated in a predetermined rule, and wakes up the label by transmitting a command and switches the label to the first channel;
  • step C) the reader starts to perform an inventory process on the first channel, and determines whether the first channel has an interference signal during the execution of the inventory, and if so, performs step D); otherwise, performs step E)
  • the inventory process includes a process of transmitting and receiving data between the reader and the tag;
  • step D) determining whether the interference level of the interference signal to the inventory process is within a preset range, if yes, the reader continues to execute and completes the inventory process; otherwise, returns to step A);
  • the step A) further includes: A1) the reader listens to the current channel, and determines whether the signal power of the current channel exceeds a preset threshold value, if yes, determining that the current channel is occupied by other readers and performing steps
  • step A2) otherwise, the channel information of the current channel is written into the available channel list and step A4) is performed;
  • the reader listens to and receives a signal frame of the current channel
  • step A4) judging whether all the channels have been intercepted, if yes, performing step A5); otherwise, acquiring the next channel and returning to step A1);
  • the step A) further includes:
  • the upper layer system transmits the list of available channels to the reader through the interface.
  • the first channel is a channel with the lowest channel noise level in the available channel list or a channel with a better channel quality in the available channel list. Any of the channels.
  • the command sent by the reader in the step B) includes at least the channel number of the first channel and the time required for the label to be transferred to the first channel. information.
  • the channel information includes frequency point information or/and status information or/and noise level or/and channel number.
  • the time at which the reader listens is at least greater than the maximum value of the transceiving conversion time of the reader and the tag.
  • the present invention also relates to an apparatus for implementing the above method for preventing collision of a multi-reader, comprising:
  • a list obtaining module configured to enable a reader to obtain a list of available channels; the available channel list includes channel information of each channel;
  • Channel selection and switching module for causing the reader to proceed from the available channel with predetermined rules Selecting the first channel as a channel to work in the list, and waking up the label by sending a command and switching the label to the first channel;
  • An inventory and channel judging module is configured to enable the reader to start performing an inventory process on the first channel, and determine whether the first channel has an interference signal during the performing the inventory process; the inventory process includes reading The process of sending and receiving data between the device and the tag;
  • the interference level judging module is configured to determine whether the interference level of the interference signal to the inventory process is within a preset range, if yes, the reader continues to execute and complete the inventory process; and the inventory execution and completion module: The reader is caused to execute in the normal flow and complete the inventory process.
  • the list obtaining module further includes:
  • Channel listening and judging unit configured to enable the reader to listen to the current channel, and determine whether the signal power of the current channel exceeds a preset threshold, and if so, determine that the current channel is occupied by other readers; Transmitting channel information of the current channel into the list of available channels;
  • a signal frame listening and receiving unit a signal frame for causing the reader to listen to and receive a current channel
  • the signal frame parsing and judging unit is configured to parse the signal frame, and determine, according to the parsed information, whether other readers occupying the current channel are similar to the reader, and if yes, select according to a predetermined priority a reader with a higher priority operates on the current channel; otherwise, exits the current channel;
  • Channel traversal unit used to judge whether all channels have been intercepted, and acquire the next channel when not being intercepted;
  • End unit Used to end this listening work.
  • the list obtaining module further includes:
  • the request sending unit is configured to: cause the reader to send a request to the upper layer system through the interface; and the list transmitting unit is configured to enable the upper layer system to transmit the available channel list to the reader through the interface.
  • the method and apparatus for implementing the multi-reader anti-collision of the present invention have the following beneficial effects: Since the reader selects the first channel from the list of available channels as the channel to be operated, and wakes up the label by sending a command and switches the label to the a first channel; the reader determines whether the first channel has an interference signal during the performing of the inventory on the first channel, and determines whether the interference level of the interference signal to the inventory process is within a preset range when the interference signal is present, such as Within the set range, the execution process is completed and completed; otherwise, the inventory process is exited, so that multiple independent mobile readers in the same application area work independently on different channels through appropriate channel selection mechanisms. This avoids mutual interference of multiple readers, so it avoids multi-reader collisions.
  • Figure 1 is a schematic diagram of collisions between different readers
  • Figure 2 is a schematic diagram of a collision when a tag simultaneously receives signals from different readers
  • FIG. 3 is a flow chart of a method for a multi-reader anti-collision method and apparatus according to an embodiment of the present invention
  • FIG. 4 is a specific flow chart of the reader in the case of obtaining an available channel list in the embodiment
  • Figure 5 is a specific flow diagram of the reader obtaining a list of available channels in another embodiment in the embodiment.
  • Figure 6 is a schematic structural view of the device in the embodiment.
  • FIG. 7 is a schematic structural diagram of a list obtaining module in the embodiment.
  • Figure 8 is a schematic diagram of the collision avoidance of two readers in the embodiment.
  • Figure 9 is another schematic view of the collision avoidance of two readers in the embodiment.
  • Figure 10 is still another schematic diagram of the collision avoidance of two readers in the described embodiment.
  • a typical RFID system usually consists of a reader and multiple tags. Usually, the system initiates the inventory process by the reader, and the check of the tags in the reader field is completed by the command or response mode. With the continuous promotion and maturity of RFID technology applications, more and more application scenarios will appear when multiple readers work simultaneously. For example, in a large warehouse, when multiple workers use handheld readers to find them separately When the item is in use, it may cause the enumeration process of a certain reader to be interfered by the reader's inventory process of the same frequency operation and cannot be performed normally.
  • FIG 1 and Figure 2 show examples of the collision of two multi-readers
  • Figure 1 is a schematic diagram of the collision of different readers.
  • R1 and R2 represent two different readers that operate independently at the same frequency.
  • T1 and T2 are the tags in the read and write fields of R1 and R2, respectively.
  • the reader antenna is omnidirectional radiation. Therefore, as shown in Figure 1, R1 and R2 fall within each other's field.
  • R1 and R2 simultaneously count different labels (T1 and T2) in their field. Even if the tags (T1 and T2) are far apart, the reader signals can reach each other, causing interference at the reading end, especially in a mobile reader environment where such collisions are more likely.
  • Figure 2 is a schematic diagram of the collision when the tag receives signals from different readers at the same time.
  • the tag T if the tag T is in the overlapping area of the common field of the two readers R1 and R2, the tag may be received at the same time.
  • signal interference occurs at the tag end, that is, multi-reader collision.
  • the present invention proposes a multi-reader anti-collision method and apparatus.
  • FIG. 3 a flowchart of the method is shown in FIG. 3, and the method includes:
  • Step S01 The reader obtains a list of available channels: In this step, the reader obtains a list of available channels, and the list of available channels includes channel information of each available channel.
  • the channel information in the RFID system generally refers to the frequency and occupied width information required for system communication commonly known by the reader and the tag. When the occupied width is consistent, the frequency point information is usually used to represent the channel information.
  • the reader obtains channel list information, which means that the reader obtains available frequency point information.
  • the acquisition method mainly adopts two ways of the reader self-detection analysis acquisition or the RFID system to provide the available channel list information. In other words, the reader passes The channel information and the list of available channels are obtained by scanning analysis of the external channel environment or by the upper layer network of the RFID system.
  • Scanning analysis by the reader through the external channel environment means that the reader listens to the channels allowed by all systems and records relevant parameters that can be used to describe the channel quality, and uses the channel information and the available channel list for channel selection.
  • Obtaining channel information and channel list information through the upper layer network of the RFID system means that the available channel information and available channel list in the current use environment of the reader have been obtained in real time by the RFID device through other devices and other methods, and the information is passed through the RFID system.
  • the interface between the middle reader and the upper system is transmitted to the reader for use by the reader.
  • the channel information includes frequency point information and/or status information and/or noise level or/and channel number, wherein the status information is information such as idle/busy of the channel.
  • Step S02 The reader selects the first channel from the list of available channels as a channel to be operated by a predetermined rule, and wakes up the label by transmitting a command and switches the label to the first channel:
  • the reader is available from the predetermined rule. Selecting the first channel as the channel to be operated in the channel list, and waking up the label by sending a command and switching the label to the first channel, in fact, the reader selects the first channel from the list of available channels as a channel to be used according to a predetermined rule. And send a command to perform the inventory initialization process.
  • the channel selected by the reader is referred to as a first channel.
  • the reader selects the first channel by a predetermined rule, that is, the reader can select a better channel according to the order of the channel quality; or select one channel arbitrarily within the identified available quality channel range.
  • the reader according to the channel quality refers to selecting a channel with a lower channel noise level as the selected channel according to the detected channel noise level of the available channel. For no more specific available channel noise level information, it is randomly selected in the available channel list or selected in other orders.
  • the first channel is any one of the channels with the lowest channel noise level in the available channel list or the channel with the better channel quality setting in the available channel list. The number of the above settings can be set accordingly according to specific needs.
  • the reader sends a command to initialize the inventory.
  • the wakeup command is first sent, and then the start command of the tag count is sent; for example, the work specified in GJB 7377.2-2011 is satisfied.
  • the RFID system first wakes up the sleeping tag through the low frequency exciter, or continuously sends a ready command for a certain period of time to make the periodically dormant tag awake.
  • the reader simultaneously sets the selected channel number (channel number) through the ready command, and instructs the tag to switch to the new channel (the first channel in this embodiment) for a certain period of time.
  • the reader sends the start command of the tag count directly.
  • a passive RFID system that satisfies ISO / IEC 18000-6 Type C
  • the tag since the tag operates in a back-illuminated mode, when the reader adjusts to a new channel (the first channel in this embodiment), read
  • the device only needs to send the Query command directly on the new channel, and the tag will switch to the new channel (the first channel in this embodiment) by detecting the received carrier.
  • the reader needs to transmit the channel selection result information and the working method information transferred to the selected channel in the start command of transmitting the label inventory.
  • the channel selection result information transmitted by the reader and the working method information transferred to the selected channel may also be partially or completely transmitted to the tag by the wakeup command.
  • the channel selection result information includes at least system working channel serial number (number) information
  • the working method information transferred to the selected channel includes at least conversion time information (time required for the label to be converted to the selected channel).
  • the command sent by the reader includes at least the channel number of the first channel and the time information required for the label to be transferred to the first channel.
  • the reader sends a wake-up or ready command for initialization
  • the default channel is generally the same, so multiple initialization command collisions may occur, for example, in meeting GJB 7377.2-2011
  • multiple readers may collide when the default channel sends a ready command, so that multiple readers cannot complete initialization.
  • it can be randomized. Resend after delay.
  • Step S03 The reader starts to perform an inventory process on the first channel, and determines whether there is an interference signal on the first channel during the execution of the inventory process:
  • the reader starts performing the inventory process on the first channel, that is, reading
  • the device begins the normal inventory process in the predetermined single reader environment on the first channel that has been selected, that is, the reader performs the tag inventory process on the first channel in accordance with the communication protocol in the normal single reader environment. For example, in an active RFID system operating at 2.45 GHz as specified in GJB 7377.2-2011, the reader sends a ready command to switch the tag to the newly set channel (first channel) and send the access command completion tag.
  • the anti-collision process is followed by sending a collection command to collect information such as the tag TID, and finally reading and writing information on the tag during the session, and then sending a sleep command to make the tag sleep.
  • the above inventory process includes the process of transmitting and receiving data between the reader and the tag. In the process of performing the inventory, it is determined whether the first channel has an interference signal. If the result of the determination is yes, step S05 is performed; if the result of the determination is no, step S04 is performed.
  • Step S04 The reader executes according to the normal flow and completes the inventory process: If the result of the above step S03 is NO, the step is executed. In this step, the reader performs the normal process and completes the inventory process.
  • Step S05 determines whether the interference level of the interference signal to the inventory process is within a preset range: if the determination result of the above S03 is YES, the step is performed. In this step, it is determined whether the interference level of the interference signal to the counting process is within a preset range.
  • the preset range is various, for example: setting a set number of times or setting time in advance, such as the reader continuously to the label The command to send the set number of times does not get a reply from the tag; or the reader does not get a reply to the tag within the set time after sending the command to the tag; the above set number or set time is the preset range.
  • the preset range can also be set to other conditions. In this step, if the result of the determination is yes, step S06 is performed; if the result of the determination is no, the process returns to step S01.
  • the reader when the reader performs the single reader normal inventory process during the selected channel (first channel), the reader can receive and parse the neighboring reader by the interference due to the interference. Signal information and confirm whether there is multi-reader interference, or the reader can listen to the channel and analyze the channel environment and confirm whether the channel is interfered. When the reader detects interference, it can decide whether to exit the first according to the preset conditions. One channel.
  • the reader detects that channel interference cannot continue normal. It means that if the channel (first channel) on which the reader works is disturbed, the reader can listen to the channel if the normal communication between the reader and the tag cannot be completed.
  • the new reader signal can further receive and parse the signal to confirm the presence of multiple readers. In a multi-reader environment, especially in a mobile reader environment, it is possible to select readers of the same channel that are separated by a long distance because they move closer together, thereby causing mutual interference.
  • the reader When the reader detects an interference signal from another interferer and causes the current channel to fail to complete the inventory, the reader can continuously send a sleep command to end the current inventory process.
  • the reader can judge whether to abandon the current channel according to the influence degree of the interference signal on the current system work and proceeds to step S01 to start a new inventory process. According to the judgment of the reader, if no other interference is found or the interference is insufficient to affect the current inventory and the current channel is not discarded, the reader continues to perform the normal inventory process until the end.
  • step S01 can be further refined, and the specific flowchart in a case after the refinement is shown in FIG. 4, and in FIG. 4, it further includes:
  • Step S10 The reader listens to the current channel and determines whether the signal power of the current channel exceeds a preset threshold. In this step, the reader listens to the current channel and determines whether the signal power of the current channel exceeds a preset. If the result of the determination is yes, step S12 is performed; otherwise, step S11 is performed. In other cases of this embodiment, the signal power may be replaced with other parameters related to channel quality.
  • Step S11 The channel information of the current channel is written into the available channel list: if the result of the above step S10 is no, the step is executed. In this step, the channel information of the current channel is written into the available channel list for subsequent selection of the channel. After performing this step, step S17 is performed.
  • Step S12 concludes that the current channel is occupied by other readers: If the result of the above step S10 is YES, then this step is performed. In this step, it is determined that the current channel is occupied by other readers.
  • Step S13 The reader listens and receives the signal frame of the current channel: In this step, for the same RFID system, the reader further listens and receives the signal frame of the current channel to further improve the operating efficiency and recognition accuracy of the RFID system. It is worth mentioning that the reader listens for at least the maximum time of the transceiver conversion time of the reader and tag of the RFID system.
  • Step S14 analyzes the signal frame, and judges whether other readers occupying the current channel and the reader are the same according to the parsed information: In this step, the signal frame is parsed, and the other channels occupying the current channel are determined according to the parsed information. Whether the reader is the same as the current reader, and if so, step S16 is performed; otherwise, step S15 is performed.
  • Step S15 Exiting the current channel: If the result of the above step S14 is no, the step is executed. In this step, the current channel is exited. After performing this step, go to step S17.
  • Step S16 selects a reader having a higher priority according to a predetermined priority to operate on the current channel: If the result of the above step S14 is YES, the step is executed. In this step, in a multi-reader environment, a reader with a higher priority is selected to work on the current channel according to a predetermined priority. After performing this step, go to step S17.
  • Step S17 It is judged whether all the licensed channels have been intercepted: In this step, it is judged whether all the licensed channels have been intercepted, and if the result of the determination is yes, step S18 is performed; otherwise, step S19 is performed.
  • Step S18 Ends the current listening operation: If the result of the above step S17 is YES, the present step is executed. In this step, the interception work is ended.
  • Step S19 continues to acquire the next channel: If the result of the above step S17 is no, the step is executed. In this step, continue to acquire the next channel. After performing this step, return to step S10.
  • the reader can separately detect all the licensed channels that are known, and determine whether the channel has a reader working according to the result of the interception.
  • Reader frame listening channel And if it is detected whether a reader occupies a certain channel, it may first determine whether the signal power of the channel exceeds a certain threshold, and if it exceeds, the channel is considered to be occupied.
  • the reader can obtain list information of available channels for subsequent selection of the working channel. If the same RFID system is used, the reader can further listen to and receive its complete signal frame, and parse its information to determine whether it is work related information for other readers.
  • FIG. 5 the specific flowchart in the other case after the step S01 is refined is shown in FIG. 5, and in FIG. 5, it further includes:
  • Step sir reader sends a request to its upper system through the interface: if it is an RFID network composed of multiple readers in the application process, that is, multiple readers may be interconnected through other networks, and the current application scope is used together.
  • the channel resources, the RFID network system can use other auxiliary devices to periodically obtain the current channel usage and the available channel list.
  • the channel information can be obtained from the network system.
  • the auxiliary device of the RFID system is connected to the reader through an interface, and the auxiliary device can control and coordinate the work between multiple readers, and the reader can feedback the problem to the auxiliary device when the problem is found. And arbitrated by the auxiliary equipment.
  • the reader sends a request to its upper system (upper network) through the interface.
  • Step S12 The upper layer system transmits the available channel list to the reader through the interface: In this step, the upper layer system transmits the available channel list to the reader through the interface, and the reader obtains the available channel list.
  • the apparatus includes a list obtaining module 1, a channel selection and switching module 2, an inventory and channel judging module 3, and an interference degree. a determination module 4 and an inventory execution and completion module 5; wherein the list acquisition module 1 is configured to enable the reader to obtain an available channel list; the available channel list includes channel information for each channel; and the channel selection and switching module 2 is configured to enable the reader to The predetermined rule selects the first channel from the list of available channels as the channel to be operated, and wakes up the label by transmitting a command and switches the label to the first channel; the inventory and channel judging module 3 is configured to make the reader on the first channel The counting process is started at the beginning, and the interference signal is judged in the first channel during the counting process; the counting process includes a process of transmitting and receiving data between the reader and the tag; and the interference level determining module 4 is configured to determine the interference signal. Whether the degree of interference to the inventory process
  • the above-mentioned list obtaining module 1 further includes a channel sensing and determining unit 11, a signal frame listening and receiving unit 12, a signal frame analyzing and determining unit 13, a channel traversing unit 14, and an ending unit 15; wherein, the channel sensing and determining unit 11 For causing the reader to listen to the current channel and determine whether the signal power of the current channel exceeds a preset threshold, and if so, conclude that the current channel is occupied by other readers; otherwise, write channel information of the current channel to the
  • the signal frame listening and receiving unit 12 is configured to enable the reader to listen to and receive the signal frame of the current channel; the signal frame parsing and determining unit 13 is configured to parse the signal frame, and judge according to the parsed information.
  • Whether other readers occupying the current channel are similar to the above-mentioned readers, for example, selecting a reader with a higher priority according to a predetermined priority to operate on the current channel; otherwise, exiting the current channel; the channel traversal unit 14 is used to judge all Whether the channel has been listened to and gets the next channel when it is not being listened to End unit 15 ends the listener for work.
  • FIG. 7 is a schematic structural diagram of a list obtaining module in another embodiment in this embodiment.
  • the list obtaining module 1 further includes a request transmitting unit 11, and a list transmitting unit 12, wherein the request transmitting unit 11 is configured to enable the reader to send a request to its upper layer system through the interface; the list transmitting unit 12' is used for The upper system is caused to transmit the list of available channels to the reader through the interface.
  • FIG. 8 to FIG. 10 are schematic diagrams of the multi-reader anti-collision method in the embodiment to ensure that the multiple readers work together.
  • FIG. 8 is a schematic diagram of the collision avoidance of two readers in the embodiment
  • FIG. 9 is another schematic diagram of the collision avoidance of the two readers in the embodiment
  • FIG. 10 is an example of preventing the two readers in the embodiment.
  • Another schematic diagram of the collision In Figure 8 to Figure 10, the RFID system meets the active radio frequency identification system operating at 2.45 GHz as specified in GJB 7377.2-2011, and the tag is in a periodic sleep/wake state before the inventory.
  • the readers R1 and R2 are handheld readers held by different workers and are used independently.
  • the working process of the multi-reader anti-collision method provided by the invention is as follows:
  • the reader R1 counts the tag T1 in its field before the reader R2 and communicates with the tag T1, and its working channel is channel 1.
  • the reader R2 arbitrarily selects the channel 5 as the channel to be used for the inventory process from the channel 2 to the channel 15.
  • the reader R2 first sends a ready command of at least two sleep cycles to wake up the tag T2.
  • the ready command contains the channel number (channel number) of 5 and the switching delay (the time it takes to switch to the selected channel) is lms.
  • the tag T2 switches to the channel 5 in lms to wait for the subsequent inventory command of the reader R2 according to the channel information indicated by the ready command.
  • Readers R1 and R2 check the labels T1 and T2 on channel 1 and channel 5, respectively, until the end of the inventory, and readers R1 and R2 send sleep commands to tags T1 and T2, respectively, to go to sleep. The inventory process did not encounter interference from other readers.
  • the reader works independently on different channels through an appropriate channel selection mechanism, and the multi-reader anti-collision method can effectively solve the multi-reader collision problem in the RFID application, and the multi-reader It can work simultaneously and without interference, thus solving the problem of multi-reader coexistence in complex RFID application scenarios, and further judging whether there is interference in the process of inventory, and corresponding processing according to the degree of interference, improving the RFID system. Operational efficiency and identification accuracy. It is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

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  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un procédé anti-collision et un dispositif pour un lecteur multiple. Le procédé comprend les étapes suivantes : un lecteur obtient une liste de canaux disponibles ; le lecteur sélectionne un premier canal à partir de la liste de canaux disponibles en tant que canal de trafic conformément à une règle prédéfinie, active une étiquette par l'envoi d'un ordre et commute l'étiquette sur le premier canal ; le lecteur lance un processus d'inventaire sur le premier canal et détermine si un signal d'interférence existe dans le premier canal dans le processus d'inventaire, si tel est le cas, la prochaine étape est effectuée ; il est déterminé si le degré d'interférence, à hauteur duquel le signal d'interférence interfère dans le processus d'inventaire, se trouve dans une plage prédéfinie, si tel est le cas, le lecteur poursuit et achève le processus d'inventaire ; et dans le cas contraire, un retour est effectué ; le lecteur effectue et achève le processus d'inventaire conformément à une procédure normale. Grâce au procédé anti-collision et au dispositif pour lecteur multiple selon la présente invention, il est possible d'obtenir un avantage consistant à éviter la collision du lecteur multiple.
PCT/CN2013/071020 2013-01-25 2013-01-28 Procédé anti-collision et dispositif pour lecteur multiple WO2014113988A1 (fr)

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CN106878918A (zh) * 2016-05-31 2017-06-20 宁波联盛信息科技有限公司 一种大规模无线电子标签系统的数据交付控制方法
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CN106650538B (zh) * 2016-12-28 2019-03-26 北京安拓思科技有限责任公司 一种rfid阅读器防碰撞方法及系统
CN107331050B (zh) * 2017-07-04 2019-10-11 深圳正品创想科技有限公司 货物盘点方法及其系统
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