Method for identifying tags using adaptive binary tree splitting technique in RFID system and RFID system therefore

A method of identifying a plurality of tags using an adaptive binary tree splitting technique in an RFID system, the method, when a period, in which RFID tags each send a signal, including an ID, to an RFID reader and the RFID reader sends a feedback, is defined as a time slot, and a plurality of time slots, which are required by the RFID reader to identify all the RFID tags within a current identification range of the RFID reader, constitutes a tag identification frame, enabling the RFID reader to identify all of the RFID tags in such a way that the RFID tags send signals in different time slots of a single tag identification frame:

• wherein each of the RFID tags has a progressive slot counter value, indicating a number of time slots in each of which an RFID tag has been identified, an assigned slot counter value, that is, a time slot number, indicating a sequential position for sending of a signal to the RFID reader and a termination slot counter value indicating the number of tag groups that should be identified by the reader in a tag identification frame;
• the method comprising:
• a first step of initializing the progressive slot counter value to 0 at a start of a tag identification frame;
• a second step of determining whether the assigned slot counter value of the RFID tag is identical to the progressive slot counter value in a current time slot, and sending a signal, including an ID thereof, to the RFID reader if the two values are identical to each other, and maintaining a standby state if the two values are not identical to each other;
• a third step of setting the progressive slot counter value and the assigned slot counter value according to received time slot type information when one piece of information selected from collision type information, indicating that signals from the RFID tags collide with each other, idle type information, indicating that there are no signals from the RFID tags, and readable type information, indicating that a signal has been received from a single RFID tag and the corresponding RFID tag has been identified, is received from the RFID reader that feeds type information of the current time slot back to all the RFID tags within an identification range of the RFID reader, depending on a number of signals received from the RFID tags;
• wherein when the progressive slot counter value of each of the RFID tags equals the assigned slot counter value, each of the RFID tags that caused a collision selects a number of either a 1 or 0 which is added to the assigned slot counter value and the tag group of RFID tags that caused a collision is divided into two sub-groups with tags of the sub-groups sending signals, including IDs thereof, to the RFID reader in different time slots for the respective sub-groups such that all of the RFID tags will send signals in different time slots of a single tag identification frame, and
• a fourth step of terminating the tag identification frame when the slot counter value is identical to the progressive slot counter value and returning to the second step if all of the tags have not been identified.

A method of identifying a plurality of tags using an adaptive binary tree splitting technique in an RFID system, the method, when a period, in which RFID tags each send a signal, including an ID, to an RFID reader and the RFID reader sends a feedback, is defined as a time slot, and a plurality of time slots, which are required by the RFID reader to identify all the RFID tags within a current identification range of the RFID reader, constitutes a tag identification frame, enabling the RFID reader to identify all the RFID tags in such a way that the RFID tags send signals in different time slots of a single tag identification frame:

• wherein the RFID has a progressive slot counter value, indicating a number of time slots in each of which an RFID tag has been identified, and a termination slot counter value, indicating a number of tag groups to be identified by the RFID reader in a single tag identification frame;
• the method comprising:
• a first step of initializing the progressive slot counter value thereof to 0 at a start of a tag identification frame;
• a second step of feeding one piece of information selected from collision type information of a current time slot when signals are received from a plurality of RFID tags which indicate that the received signals have collided with each other, idle type information, indicating that there are no signals from the RFID tags, and readable type information, indicating that a signal has been received from a single RFID tag and the corresponding RFID tag has been identified, back to all the RFID tags within the identification range of the RFID reader, as type information of a current time slot, depending on the number of signals received from the RFID tags, in the current time slot, and setting the progressive slot counter value and termination slot counter value of the RFID reader according to the sent time slot type information, wherein if the received signals indicate the plurality of RFID tags have collided decreasing the termination slot counter value by 1;
• and
• a third step of determining whether the progressive slot counter value is identical to the termination slot counter value, terminating the tag identification frame if the two values are identical to each other, and returning to step 2 if the two values are not identical to each other.