RFID system

Abstract

The present invention provides an RFID system, which belongs to the field of communication technology. An exciter is used to receive an RN16 message from a tag, start a second timer, and send a confirmation message of the RN16 message to the tag before the second timer times out; a tag is used to send the RN16 message to the exciter, receive a confirmation message of the RN16 message sent by the exciter, report the EPC to a receiver, start a second timer, enter the arbitrate state after the second timer times out, and receive a select command sent by the receiver to switch the session state; a receiver is used to receive the EPC reported by the tag, start a second timer, and send a select command to the tag after the second timer times out, instructing the tag to switch the session state. The technical solution of the present invention can reduce costs while meeting the RFID protocol delay.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to an RFID system. Background Art

[0002] The current RFID architecture has the following problems in order to meet the latency requirements:

[0003] 1. Requires significant hardware and software costs, and imposes many architectural design restrictions to achieve latency requirements.

[0004] 2. The communication protocol between the receiver and the exciter has very high latency requirements. General communication protocols such as WIFI, BT, 5G and even some streamlined short-range communications cannot meet them. They need to rely on customized private protocols, which have many restrictions and greatly reduce the compatibility and scalability of the solution.

[0005] 3. The transmission rate is limited and can only be maintained at a lower rate, such as 40K or 160K. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an RFID system that can reduce costs and improve the compatibility and scalability of the solution while meeting the RFID protocol delay.

[0007] To solve the above technical problems, the embodiments of the present invention provide the following technical solutions:

[0008] In one aspect, an RFID system is provided, comprising:

[0009] An exciter, configured to receive an RN16 message from a tag, start a second timer, and send a confirmation message of the RN16 message to the tag before the second timer expires; or send a first queryrep message to the tag, wherein the first queryrep message indicates that the session does not match;

[0010] The tag is used to send the RN16 message to the exciter, receive a confirmation message of the RN16 message sent by the exciter, report the EPC to the receiver, start a second timer, enter the arbitrate state after the second timer times out, and receive a select command sent by the receiver to switch the session state; or, after receiving a first queryrep message from the exciter, stop the second timer and start the first timer and the third timer, after the first timer and the third timer time out, receive a confirmation message of the RN16 message sent by the receiver, report the EPC to the receiver, and receive a second queryrep message sent by the receiver, the first queryrep message indicating a session mismatch, and the second queryrep message indicating a session match;

[0011] The receiver is used to receive the EPC reported by the tag, start a second timer, and send a select command to the tag after the second timer times out, instructing to switch the session state; or, receive the EPC reported by the tag, send a second queryrep message to the tag, instructing to switch the session state.

[0012] In some embodiments, the receiver is integrated into the exciter.

[0013] In some embodiments, if the EPC is invalid,

[0014] The tag is further used to start a second timer after reporting the EPC to the receiver, and after the second timer times out, enter the arbitrate state without performing session state switching.

[0015] In some embodiments, the receiver is further configured to send a first query message to the actuator, instructing the actuator to perform a read or write operation;

[0016] The activator is further configured to receive a first query message sent by the receiver, perform read and write operations, and after receiving the EPC returned by the tag, start a second timer and send a REQ_RN to the tag before the second timer times out;

[0017] The tag is used to send the EPC to the receiver, receive the REQ_RN sent by the activator, and return a handle to the activator.

[0018] In some embodiments, the exciter is specifically configured to receive only the preamble portion of the EPC, or receive the entire EPC.

[0019] In some embodiments, if the EPC is invalid,

[0020] The receiver is further configured to send a first instruction to the tag, instructing the tag to return to the EPC again; or

[0021] The receiver is further configured to send a second query message to the tag to trigger the next round of rereading; or

[0022] The activator is further configured to send a second instruction to the tag when the tag is in the acknowledge state, instructing the tag to return to the EPC again; or

[0023] The receiver is further configured to, when the tag is in the arbitrate state, send a third instruction to the tag, instructing the tag to return to the EPC again; or

[0024] The actuator is further configured to send a third query message to the tag to trigger the next round of rereading.

[0025] In some embodiments, the receiver and the exciter are independent of each other.

[0026] In some embodiments, the exciter is further configured to send a fourth query message to the tag, start a second timer after the tag enters a reply state, and send a third queryrep message to the tag before the second timer expires, indicating that the session does not match;

[0027] The tag is further configured to, after receiving the third queryrep message, remain in a reply state, stop the second timer, start the first timer and the third timer, receive a confirmation message sent by the receiver after the first timer and the third timer expire, and send an EPC to the receiver.

[0028] In some embodiments, if the EPC is invalid,

[0029] The tag is further used to start a second timer after reporting the EPC to the receiver, and after the second timer times out, enter the arbitrate state without performing session state switching.

[0030] In some embodiments, the actuator is further configured to start a second timer after sending the confirmation message to the tag, and send a fourth queryrep message to the tag before the second timer expires, indicating that the session does not match;

[0031] The tag is further configured to, after receiving the fourth queryrep message, remain in the acknowledged state, stop the second timer, and start the first timer and the third timer; after the first timer and the third timer expire, receive the fifth query message sent by the receiver and perform the next round of inventory.

[0032] In some embodiments, the receiver is further configured to send a sixth query message to the actuator, instructing the actuator to send a fifth queryrep message to the tag after sending the confirmation message to the tag, indicating that the session does not match;

[0033] The activator is also used to start a second timer after sending a confirmation message to the tag, and send a fifth queryrep message to the tag before the second timer times out, indicating that the session does not match; stop the second timer, start the first timer and the third timer, and after the first timer and the third timer time out, transparently transmit the REQ_RN command sent by the receiver to the tag.

[0034] The embodiments of the present invention have the following beneficial effects:

[0035] In the above solution, the limitation of T2 (i.e., the second timer) delay on system design is removed, which is conducive to the use of more flexible, mature and low-cost communication protocols between communication equipment and exciters, such as WIFI, BT or other streamlined short-distance communication protocols; it solves the problem of limited transmission rate and can achieve higher rates, such as 256K, 320K, and even 640K. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the existing RFID architecture with separate transmitter and receiver;

[0037] Figure 2 A schematic diagram of the limit point T2 of the integrated reader in the prior art;

[0038] Figure 3-Figure 5 This is a schematic diagram of the interaction process of the RFID system according to the first embodiment of the present invention;

[0039] Figure 6 This is a schematic diagram of the abnormal response link timing;

[0040] Figure 7-11 This is a schematic diagram of the interaction process of the RFID system in embodiment 2 of the present invention. DETAILED DESCRIPTION

[0041] In order to make the technical problems, technical solutions and advantages to be solved by the embodiments of the present invention clearer, they will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] The existing RFID (Radio Frequency Identification) architecture with separate transmitter and receiver is as follows: Figure 1 As shown in the figure, the receiver is responsible for selecting and controlling the exciter and transmitting the excitation signal. It is also responsible for configuring various exciter resources, such as the frequency hopping sequence, time and frequency division strategies, antenna configuration, and transmit power. It is also responsible for receiving and demodulating the tag's reflected signal. The exciter transmits the excitation signal to energize the tag, sends various read control signals such as select, inventory, and access, and responds to the receiver's commands with an ACK. After being energized, the tag transmits its information on the reflected signal to the receiver.

[0043] The RFID protocol has very high requirements for latency, and the most important one is T2 (3.0Tpri-20.0Tpri) which is a microsecond delay. In the existing RFID protocol process, the T2 limit of the integrated reader is as follows: Figure 2 As shown, among them, limit point 1 is between steps 3 and 4, and the delay requirement is T2; limit point 2 is between steps 5 and 6, and the delay requirement is T2; limit point 2.1 is between steps 5 and 6.1, and the delay requirement is T2. After returning a valid EPC, the tag expects to receive QueryRep within T2, the tag enters the ready state, and the session state changes from A->B, and the reading is completed; limit point 2.2 is between steps 5 and 6.2, and the delay requirement is T2. After returning an invalid EPC, the tag expects to receive NAK within T2, the tag enters the arbitrate state, the session remains A, and waits to be read again; limit point 2.3 is between steps 5 and 6.3, and the delay requirement is T2. After returning a valid EPC, the tag expects to receive Req_RN within T2, and continues to read other areas of the tag, and the session remains A.

[0044] In a separate transceiver architecture, since the reader / writer is separated into two devices, a new device latency is introduced, making latency limitations more prominent:

[0045] 1. Device operation delay (main delay): Originally, there was only one reader operation delay, but now two delays, the receiving device and the excitation device, have been introduced.

[0046] 2. Transmission delay between the receiving device and the stimulating device: The RN16 generated by the tag must first be sent to the receiving device, which then sends it to the stimulating device. The stimulating device then sends an ACK (carrying the RN16) to the tag. Therefore, the RN16 communication process between the receiving device and the stimulating device introduces a new delay.

[0047] In existing technologies, to meet the T2 delay requirement, improvements are required in the following aspects:

[0048] 1. Hardware: such as FPGA, ASIC chips, couplers, mixers, etc.; introduces many restrictions and increases design and device costs.

[0049] 2. Bottom-level software: This requires signal design and data processing algorithm optimization to meet latency requirements. This places significant restrictions on the choice of communication protocols. It is necessary to select and design a protocol architecture with shorter symbols and shorter signaling and data transmission lengths. The currently widely used short-distance protocols are basically unable to meet these requirements, and a set of private protocols needs to be redesigned to meet latency requirements.

[0050] 3. Transmission rate: Due to delay limitations, assuming the delay between the exciter and receiver can be controlled within 80us, a rate of 320K or even 640K cannot be achieved. To achieve this, the transmission delay must be significantly increased again, increasing costs.

[0051] In summary, the existing solutions have the following defects:

[0052] 1. Requires significant hardware and software costs, and imposes many architectural design restrictions to achieve latency requirements.

[0053] 2. The communication protocol between the receiver and the exciter has very high latency requirements. General communication protocols such as WIFI, BT, 5G and even some streamlined short-range communications cannot meet them. They need to rely on customized private protocols, which have many restrictions and greatly reduce the compatibility and scalability of the solution.

[0054] 3. The transmission rate is limited and can only be maintained at a lower rate, such as 40K or 160K.

[0055] The embodiment of the present invention provides an RFID system, which can reduce costs and improve the compatibility and scalability of the solution while meeting the RFID protocol delay.

[0056] An embodiment of the present invention provides an RFID system, including:

[0057] An exciter, configured to receive an RN16 message from a tag, start a second timer, and send a confirmation message of the RN16 message to the tag before the second timer expires; or send a first queryrep message to the tag, wherein the first queryrep message indicates that the session does not match;

[0058] The tag is used to send the RN16 message to the exciter, receive a confirmation message of the RN16 message sent by the exciter, report the EPC to the receiver, start a second timer, enter the arbitrate state after the second timer times out, and receive a select command sent by the receiver to switch the session state; or, after receiving a first queryrep message from the exciter, stop the second timer and start the first timer and the third timer, after the first timer and the third timer time out, receive a confirmation message of the RN16 message sent by the receiver, report the EPC to the receiver, and receive a second queryrep message sent by the receiver, the first queryrep message indicating a session mismatch, and the second queryrep message indicating a session match;

[0059] The receiver is used to receive the EPC reported by the tag, start a second timer, and send a select command to the tag after the second timer times out, instructing to switch the session state; or, receive the EPC reported by the tag, send a second queryrep message to the tag, instructing to switch the session state.

[0060] In this embodiment, the limitation of T2 delay on system design is removed, which is conducive to the use of more flexible, mature and low-cost communication protocols between communication equipment and exciters, such as WIFI, BT or other streamlined short-range communication protocols; it solves the problem of limited transmission rate and can achieve higher rates, such as 256K, 320K, and even 640K.

[0061] In this embodiment, the tag memory is divided into four independent storage blocks (Banks): Reserved, EPC (Electronic Product Code), TID (Tag Identification Number), and User. The Reserved area: stores the Kill Password and Access Password. The EPC area: stores the EPC number, etc. The TID area: stores the tag identification number. Each TID number should be unique. The User area: stores user-defined data. The tag can be in one of seven states: Ready, Arbitrate, Reply, Acknowledged, Open, Secured, and Killed. The commands supported by this embodiment include: Select, Query, QueryAdjust, QueryRep, ACK, EPC reply, NAK, Req_RN, Read, Write, Kill, and Lock.

[0062] In some embodiments, the receiver is integrated into the exciter. That is, a receiving circuit is added to the exciter of the separated architecture, which is responsible for directly processing RN16 and EPC reception, and returning ACK or other commands to the tag within the T2 (i.e., the second timer) delay to meet the delay requirement. The exciter can introduce a self-interference elimination circuit. At the same time, since the RFID system separation architecture of this embodiment is a distributed deployment, the exciter is deployed close to the tag and has little impact. The data reflected by the tag, such as EPC, is still received by the receiver, and can still enjoy the long-distance reception brought by the high sensitivity of the receiver.

[0063] In some embodiments, if the EPC is invalid,

[0064] The tag is further used to start a second timer after reporting the EPC to the receiver, and after the second timer times out, enter the arbitrate state without performing session state switching.

[0065] In some embodiments, the receiver is further configured to send a first query message to the actuator, instructing the actuator to perform a read or write operation;

[0066] The activator is further configured to receive a first query message sent by the receiver, perform read and write operations, and after receiving the EPC returned by the tag, start a second timer and send a REQ_RN to the tag before the second timer times out;

[0067] The tag is used to send the EPC to the receiver, receive the REQ_RN sent by the activator, and return a handle to the activator.

[0068] In some embodiments, the exciter is specifically configured to receive only the preamble portion of the EPC, or receive the entire EPC.

[0069] In some embodiments, if the EPC is invalid,

[0070] The receiver is further configured to send a first instruction to the tag, instructing the tag to return to the EPC again; or

[0071] The receiver is further configured to send a second query message to the tag to trigger the next round of rereading; or

[0072] The activator is further configured to send a second instruction to the tag when the tag is in the acknowledge state, instructing the tag to return to the EPC again; or

[0073] The receiver is further configured to, when the tag is in the arbitrate state, send a third instruction to the tag, instructing the tag to return to the EPC again; or

[0074] The actuator is further configured to send a third query message to the tag to trigger the next round of rereading.

[0075] This embodiment will be further described below with reference to the accompanying drawings.

[0076] In this embodiment, during the normal process of EPC inventory, Figure 3 As shown, the following steps are included:

[0077] The receiver sends PowerUp to the exciter, instructing it to power on;

[0078] The activator sends PowerUp to the tag, instructing it to power on.

[0079] The tag enters the ready state;

[0080] The receiver sends a query message to the activator, indicating SessionA;

[0081] The activator sends a query message to the tag, indicating SessionA;

[0082] The tag enters the reply state;

[0083] The tag sends RN16 to the exciter;

[0084] The exciter sends RN16 to the receiver;

[0085] The tag starts T2 and enters the acknowledge state after T2 times out;

[0086] The exciter sends an ACK (RN16) to the tag within T2.

[0087] The tag sends EPC to the receiver, starts T2, and enters the arbitrate state after T2 times out.

[0088] After receiving the EPC, the receiver triggers the select command (masks the current EPC tag and switches the session state from A to B). The activator transparently transmits the command to the tag for execution, and the tag completes the marking of the read tags in the arbitrate state.

[0089] In this embodiment, in the RN16 conflict process, the receiver does not send an ACK, but adjusts the Q value through query / queryadjust or query command and continues to take inventory.

[0090] In this embodiment, in the EPC invalidation process, if Figure 4 As shown, the following steps are included:

[0091] The receiver sends PowerUp to the exciter, instructing it to power on;

[0092] The activator sends PowerUp to the tag, instructing it to power on.

[0093] The tag enters the ready state;

[0094] The receiver sends a query message to the activator, indicating SessionA;

[0095] The activator sends a query message to the tag, indicating SessionA;

[0096] The tag enters the reply state;

[0097] The tag sends RN16 to the exciter;

[0098] The exciter sends RN16 to the receiver;

[0099] The tag starts T2 and enters the acknowledge state after T2 times out;

[0100] The exciter sends an ACK (RN16) to the tag within T2.

[0101] The tag sends EPC (invalid) to the receiver, starting T2. After T2 times out, the tag enters the expired arbitrate state. The current tag session does not switch and remains in A, waiting for the next round of inventory.

[0102] After receiving the EPC, the receiver sends a Query message to the activator, which is transparently transmitted to the tag for execution, and the tag enters the reply state.

[0103] In this embodiment, in the EPC subsequent process, the receiver triggers a special Query (Req_RN) to instruct the activator to perform a read / write operation. Then, after the tag returns the EPC, the activator must send a REQ_RN to the tag within T2, and the tag returns a handle. The activator's reception of the EPC can be divided into two situations:

[0104] Case 1: Only the preamble part is received, that is, it is determined that the EPC has been received, but its validity cannot be determined. However, this can reduce the reception complexity of the exciter.

[0105] Case 2: All EPCs are received and their validity can be determined.

[0106] When EPC is invalid:

[0107] For case 1, the activator cannot determine the validity of the EPC, so it will send REQ_RN regardless of whether it is valid. The tag enters the open state. At this time, the receiver can send ACK to let the tag return the EPC again, or give up this round of inventory and send query to trigger the next round of rereading.

[0108] For case 2, the stimulator can determine the validity of the EPC. When the tag is in the acknowledge state (T2 has not timed out), the stimulator can send an ACK to the tag, allowing the tag to return the EPC again. Alternatively, when the tag is in the arbitrate state (T2 has timed out), the receiver can send an ACK to the tag, allowing the tag to return the EPC again. Alternatively, the current inventory round can be abandoned and a query can be sent to trigger the next round of rereading.

[0109] Take the exciter sending REQ_RN as an example, Figure 5 As shown, the following steps are included:

[0110] The receiver sends PowerUp to the exciter, instructing it to power on;

[0111] The activator sends PowerUp to the tag, instructing it to power on.

[0112] The tag enters the ready state;

[0113] The receiver sends a query message to the exciter, indicating Req_RN;

[0114] The activator sends a query message to the tag, indicating Req_RN;

[0115] The tag enters the reply state;

[0116] The tag sends RN16 to the exciter;

[0117] The exciter sends RN16 to the receiver;

[0118] The tag starts T2 and enters the acknowledge state after T2 times out;

[0119] The activator sends an ACK (RN16) to the tag within T2.

[0120] The tag sends EPC to the receiver through the activator, starting T2. After T2 times out, the tag enters the open state;

[0121] The activator sends Req_RN to the tag within T2, and the tag returns a handle.

[0122] Compared with related technologies, this embodiment removes the limitation of T2 delay on system design; redesigns some processes to be compatible with the original protocol; this architecture is conducive to the use of more flexible, more mature and lower-cost communication protocols between communication devices and excitation devices, such as WIFI, BT or other streamlined short-range communication protocols.

[0123] In some embodiments, the receiver and the exciter are independent of each other. The exciter does not need to add a receiving circuit. Instead, at the T2 limit point, the exciter sends a queryrep (session mismatch) command to the tag within the T2 delay, causing the tag to stop T2 and remain in the current state (e.g., reply / acknowledge state). The tag can then continue to respond with ACK or Req_RN, thus removing the T2 limit.

[0124] In some embodiments, the exciter is further configured to send a fourth query message to the tag, start a second timer after the tag enters a reply state, and send a third queryrep message to the tag before the second timer expires, indicating that the session does not match;

[0125] The tag is further configured to, after receiving the third queryrep message, remain in a reply state, stop the second timer, start the first timer and the third timer, receive a confirmation message sent by the receiver after the first timer and the third timer expire, and send an EPC to the receiver.

[0126] In some embodiments, if the EPC is invalid,

[0127] The tag is further used to start a second timer after reporting the EPC to the receiver, and after the second timer times out, enter the arbitrate state without performing session state switching.

[0128] In some embodiments, the actuator is further configured to start a second timer after sending the confirmation message to the tag, and send a fourth queryrep message to the tag before the second timer expires, indicating that the session does not match;

[0129] The tag is further configured to, after receiving the fourth queryrep message, remain in the acknowledged state, stop the second timer, and start the first timer and the third timer; after the first timer and the third timer expire, receive the fifth query message sent by the receiver and perform the next round of inventory.

[0130] In some embodiments, the receiver is further configured to send a sixth query message to the actuator, instructing the actuator to send a fifth queryrep message to the tag after sending the confirmation message to the tag, indicating that the session does not match;

[0131] The activator is also used to start a second timer after sending a confirmation message to the tag, and send a fifth queryrep message to the tag before the second timer times out, indicating that the session does not match; stop the second timer, start the first timer and the third timer, and after the first timer and the third timer time out, transparently transmit the REQ_RN command sent by the receiver to the tag.

[0132] This embodiment will be further described below with reference to the accompanying drawings.

[0133] The abnormal response link timing diagram of the RFID tag protocol is as follows Figure 6 As shown, the interval duration between each message is limited, such as the interval duration of the first timer between queryrep and RN16, the interval duration of the second timer between RN16 and Ack, etc.

[0134] In this embodiment, in the normal process of EPC inventory, for restriction point 1, it can be solved through the RN16 timing: after the exciter sends a query, the tag enters the reply state. The exciter sends queryrep (session mismatch) to the tag within T2 time. After receiving it, the tag remains in the reply state, stops T2, and starts T1 and T3 timers (no signaling is expected to be processed during this period). After T1 + T3 timeout, the receiver sends ACK (RN16), which is relayed by the exciter to the tag. At this time, the tag will correctly return the EPC. To ensure time accuracy, the exciter can define a T-rn16 (the time for the tag to reflect RN16 < T-rn16 < T2), and T-rn16 = (1 / BLF) * length (length is the length of RN16).

[0135] For restriction point 2, it can be solved through the EPC timing, and there are two solutions:

[0136] Solution 1, the T2 timeout solution, as Figure 7 shown, includes the following steps:

[0137] The receiver sends PowerUp to the exciter, indicating power-on;

[0138] The exciter sends PowerUp to the tag, indicating power-on;

[0139] The tag enters the ready state;

[0140] The receiver sends a query message to the exciter, indicating SessionA;

[0141] The exciter sends a query message to the tag, indicating SessionA;

[0142] The tag enters the reply state;

[0143] The tag sends RN16 to the receiver;

[0144] The exciter sends queryrep (session mismatch) to the tag within T2 time;

[0145] After receiving it, the tag remains in the reply state, stops T2, and starts T1 (i.e., the first timer) and T3 (i.e., the third timer). No signaling is expected to be processed during this period;

[0146] After T1 + T3 timeout, the receiver sends ACK (RN16), which is relayed by the exciter to the tag;

[0147] The tag enters the acknowledge state;

[0148] The tag sends the EPC to the receiver, starting T2. After T2 times out, the tag enters the expired arbitrate state.

[0149] After receiving the EPC, the receiver triggers the select command (masks the current EPC tag and switches the session state from A to B). The activator transparently transmits the command to the tag for execution, and the tag completes the marking of the read tags in the arbitrate state.

[0150] Solution 2: T2 does not time out, such as Figure 8 As shown, the following steps are included:

[0151] The receiver sends PowerUp to the exciter, instructing it to power on;

[0152] The activator sends PowerUp to the tag, instructing it to power on.

[0153] The tag enters the ready state;

[0154] The receiver sends a query message to the activator, indicating SessionA;

[0155] The activator sends a query message to the tag, indicating SessionA;

[0156] The tag enters the reply state;

[0157] The tag sends RN16 to the receiver;

[0158] The exciter sends a queryrep (session mismatch) to the tag within T2;

[0159] After receiving the tag, it remains in the reply state, stops T2, and starts T1 (i.e., the first timer) and T3 (i.e., the third timer). No signaling is expected to be processed during this period;

[0160] After T1 and T3 time out, the tag enters the acknowledge state;

[0161] The receiver sends an ACK (RN16), which is transparently transmitted to the tag by the exciter;

[0162] The tag sends EPC to the receiver, starting T2;

[0163] The activator sends a queryrep (session mismatch) to the tag within T2. ​​After receiving it, the tag remains in the acknowledged state and starts T1 and T3. No signaling is expected to be processed during this time period.

[0164] After T1+T3 timeout, the receiver sends queryrep (session match), which is relayed by the exciter to the tag. At this time, the tag will correctly execute slot-- and switch the session from A to B.

[0165] To ensure time accuracy, the exciter can define a T-epc (the time for the tag to reflect EPC < T-epc < T2), where T-epc = (1 / BLF) * length (length is the length of the EPC).

[0166] In this embodiment, during the conflict process, the receiver does not send ACK. Instead, it adjusts the Q value through query / queryadjust or the query command and continues inventorying.

[0167] In this embodiment, in the EPC invalid process, it includes a T2 timeout scheme and a T2 non-timeout scheme.

[0168] For the T2 timeout scheme, as Figure 9 shown, it includes the following steps:

[0169] The receiver sends PowerUp to the exciter, indicating power-on;

[0170] The exciter sends PowerUp to the tag, indicating power-on;

[0171] The tag enters the ready state;

[0172] The receiver sends a query message to the exciter, indicating SessionA;

[0173] The exciter sends a query message to the tag, indicating SessionA;

[0174] The tag enters the reply state;

[0175] The tag sends RN16 to the receiver;

[0176] The tag starts T2;

[0177] The exciter sends queryrep (session mismatch) to the tag within T2 time. The tag stops T2 and starts T1 and T3;

[0178] After T1 and T3 timeout, the exciter sends ACK (RN16) to the tag;

[0179] The tag enters the acknowledge state;

[0180] The tag sends EPC (invalid) to the receiver, starting T2. After T2 times out, the tag enters the arbitrate state. The current tag session does not switch and remains in A, waiting for the next round of inventory.

[0181] After receiving the EPC, the receiver sends a Query message to the activator, which is transparently transmitted to the tag for execution, and the tag enters the reply state.

[0182] For the T2 non-timeout solution, such as Figure 10 As shown, the following steps are included:

[0183] The receiver sends PowerUp to the exciter, instructing it to power on;

[0184] The activator sends PowerUp to the tag, instructing it to power on.

[0185] The tag enters the ready state;

[0186] The receiver sends a query message to the activator, indicating SessionA;

[0187] The activator sends a query message to the tag, indicating SessionA;

[0188] The tag enters the reply state;

[0189] The tag sends RN16 to the receiver;

[0190] Tag start T2;

[0191] The activator sends a queryrep (session mismatch) to the tag within T2. ​​The tag stops T2 and starts T1 and T3.

[0192] The receiver sends an ACK (RN16) to the tag via the exciter.

[0193] After T1 and T3 time out, the tag enters the acknowledge state;

[0194] The tag sends EPC (invalid) to the receiver, starting T2.

[0195] The activator sends a queryrep (session mismatch) to the tag within T2. ​​The tag stops T2 and starts T1 and T3.

[0196] After T1 and T3 time out, the receiver sends a Query message to the activator, which is transparently transmitted to the tag for execution. The tag enters the reply state and performs the next round of inventory.

[0197] In this embodiment, in the EPC subsequent process, such as Figure 11As shown, it includes the following steps:

[0198] The receiver sends PowerUp to the exciter, indicating power-on;

[0199] The exciter sends PowerUp to the tag, indicating power-on;

[0200] The tag enters the ready state;

[0201] The receiver sends a query message to the exciter, indicating Req_RN. The purpose is to let the exciter send a queryrep (session mismatch) to the tag actively after sending ACK;

[0202] The exciter sends a query message to the tag, indicating Req_RN;

[0203] The tag enters the reply state;

[0204] The tag sends RN16 to the receiver;

[0205] The tag starts T2;

[0206] The exciter sends a queryrep (session mismatch) to the tag within T2 time;

[0207] After receiving it, the tag stops T2 and starts T1 and T3;

[0208] The receiver sends ACK(RN16) to the exciter;

[0209] After T1 and T3 timeouts, the exciter sends ACK(RN16) to the tag, and the tag enters the acknowledge state;

[0210] The tag sends EPC to the receiver through the exciter and starts T2;

[0211] The exciter sends a queryrep (session mismatch) to the tag within T2 time. After receiving it, the tag remains in the acknowledged state, stops T2, and starts the T1 and T3 timers. No signaling is expected to be processed during this period;

[0212] After T1+T3 timeouts, the receiver sends the REQ_RN command, which is relayed by the exciter to the tag.

[0213] To ensure time accuracy, the exciter can define a T-epc (the time when the tag reflects EPC < T-epc < T2), and T-epc = (1 / BLF) * length (length is the length of EPC).

[0214] Compared to related technologies, this embodiment eliminates the limitations imposed by T2 latency on system design and redesigns some processes to enable compatibility with existing protocols. This architecture facilitates the use of more flexible, mature, and cost-effective communication protocols between communication devices and excitation devices, such as Wi-Fi, BT, or other streamlined short-range communication protocols. Furthermore, the exciter requires no receive path, only a transmit path, eliminating the exciter self-interference issue and offering an advantage in distance between the exciter and the tag.

[0215] The solution of this embodiment can be implemented through computer-readable storage media, which includes permanent and non-permanent, removable and non-removable media that can implement information storage by any method or technology. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, read-only compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage terminal devices to be detected or any other non-transmission media that can be used to store information that can be accessed by the computer terminal devices to be detected. As defined herein, computer-readable media does not include temporary computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0216] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. An RFID system, characterized in that: include: An exciter, configured to receive an RN16 message from a tag, start a second timer, and send a confirmation message of the RN16 message to the tag before the second timer expires; or send a first queryrep message to the tag, wherein the first queryrep message indicates that the session does not match; The tag is used to send the RN16 message to the exciter, receive a confirmation message of the RN16 message sent by the exciter, report the EPC to the receiver, start a second timer, enter the arbitrate state after the second timer times out, and receive a select command sent by the receiver to switch the session state; or, after receiving a first queryrep message from the exciter, stop the second timer and start the first timer and the third timer, after the first timer and the third timer time out, receive a confirmation message of the RN16 message sent by the receiver, report the EPC to the receiver, and receive a second queryrep message sent by the receiver, the first queryrep message indicating a session mismatch, and the second queryrep message indicating a session match; The receiver is used to receive the EPC reported by the tag, start a second timer, and send a select command to the tag after the second timer times out, instructing to switch the session state; or, receive the EPC reported by the tag, send a second queryrep message to the tag, instructing to switch the session state.

2. The RFID system according to claim 1, wherein: The receiver is integrated into the exciter.

3. The RFID system according to claim 2, wherein: If the EPC is invalid, The tag is further used to start a second timer after reporting the EPC to the receiver, and after the second timer times out, enter the arbitrate state without performing session state switching.

4. The RFID system according to claim 2, wherein: The receiver is further configured to send a first query message to the actuator, instructing the actuator to perform a read and write operation; The activator is further configured to receive a first query message sent by the receiver, perform read and write operations, and after receiving the EPC returned by the tag, start a second timer and send a REQ_RN to the tag before the second timer times out; The tag is used to send the EPC to the receiver, receive the REQ_RN sent by the activator, and return a handle to the activator.

5. The RFID system according to claim 4, wherein: The exciter is specifically configured to receive only the preamble portion in the EPC, or receive the entire EPC.

6. The RFID system according to claim 4, wherein: If the EPC is invalid, The receiver is further configured to send a first instruction to the tag, instructing the tag to return to the EPC again; or The receiver is further configured to send a second query message to the tag to trigger the next round of rereading; or The activator is further configured to send a second instruction to the tag when the tag is in the acknowledge state, instructing the tag to return to the EPC again; or The receiver is further configured to, when the tag is in the arbitrate state, send a third instruction to the tag, instructing the tag to return to the EPC again; or The actuator is further configured to send a third query message to the tag to trigger the next round of rereading.

7. The RFID system according to claim 1, wherein: The receiver and the exciter are independent of each other.

8. The RFID system according to claim 7, wherein: The exciter is further configured to send a fourth query message to the tag, start a second timer after the tag enters a reply state, and send a third queryrep message to the tag before the second timer times out, indicating that the session does not match; The tag is further configured to, after receiving the third queryrep message, remain in a reply state, stop the second timer, start the first timer and the third timer, receive a confirmation message sent by the receiver after the first timer and the third timer expire, and send an EPC to the receiver.

9. The RFID system according to claim 7, wherein: If the EPC is invalid, The tag is further used to start a second timer after reporting the EPC to the receiver, and after the second timer times out, enter the arbitrate state without performing session state switching.

10. The RFID system according to claim 7, wherein: The exciter is further configured to start a second timer after sending a confirmation message to the tag, and send a fourth queryrep message to the tag before the second timer times out, indicating that the session does not match; The tag is further configured to, after receiving the fourth queryrep message, remain in the acknowledged state, stop the second timer, and start the first timer and the third timer; after the first timer and the third timer expire, receive the fifth query message sent by the receiver and perform the next round of inventory.

11. The RFID system according to claim 7, wherein: The receiver is further configured to send a sixth query message to the actuator, instructing the actuator to send a fifth queryrep message to the tag after sending a confirmation message to the tag, indicating that the session does not match; The activator is also used to start a second timer after sending a confirmation message to the tag, and send a fifth queryrep message to the tag before the second timer times out, indicating that the session does not match; stop the second timer, start the first timer and the third timer, and after the first timer and the third timer time out, transparently transmit the REQ_RN command sent by the receiver to the tag.

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