TIME SLOT ALLOCATION APPARATUS AND METHOD FOR PREVENTING COLLISIONS BETWEEN TIME SLOTS IN TDMA-BASED RFID NETWORK

• US 20100176926A1
• Filed: 11/16/2007
• Published: 07/15/2010
• Est. Priority Date: 09/21/2007
• Status: Active Grant

• Current Assignee: Geun-Sik Jo
• Original Assignee: INHA Industry Partnership Institute
• Inventors: Yu, Young Hoon, Jo, Geun Sik, Park, Seung Bo
• Granted Patent: US 8,325,017 B2
• Time in Patent Office: Days
• US Class Current: 340/10.200
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 72/563 of the wireless resources

Abstract

The present invention relates to a time slot allocation apparatus and method for preventing collisions between time slots in a TDMA-based RFID network. The time slot allocation apparatus allocates time slots, obtained by dividing a same frequency band into unit time slots, to RFID readers for reading identification codes of RFID tags (10) in the TDMA-based RFID network. A time slot allocation device (33a) allocates time slots required for communication with the RFID tags to a plurality of RFID readers (20) provided in the RFID network. A collision prevention device (33b) performs control such that the time slot allocation device allocates time slots to the plurality of RFID readers while distributing different and non-successive time slots to adjacent RFID readers, thus preventing collisions from occurring between time slots allocated to the RFID readers.

Claims

1. A time slot allocation apparatus for preventing collisions between time slots in a Time Division Multiple Access (TDMA)-based Radio Frequency Identification (RFID) network, the apparatus allocating time slots, obtained by dividing a same frequency band into unit time slots, to RFID readers for reading identification codes of RFID tags in the TDMA-based RFID network, comprising:

a time slot allocation device for allocating time slots required for communication with the RFID tags to a plurality of RFID readers provided in the RFID network; and

a collision prevention device for performing control such that the time slot allocation device allocates time slots to the plurality of RFID readers while distributing different and non-successive time slots to adjacent RFID readers, thus preventing collisions from occurring between time slots allocated to the RFID readers.

2. The time slot allocation apparatus according to claim 1, wherein the collision prevention device performs control such that three to six time slots are interposed between the time slots allocated to the adjacent RFID readers in order to read each moving RFID tag.

3. The time slot allocation apparatus according to claim 1, wherein the collision prevention device performs control such that one to four time slots are interposed between time slots allocated to the adjacent RFID readers in order to eliminate temporal interference between the time slots.

4. The time slot allocation apparatus according to claim 1, wherein the collision prevention device enables a number of time slots allocated to all RFID readers provided in the RFID network to be minimized.

5. The time slot allocation apparatus according to claim 1, wherein both the time slot allocation device and the collision prevention device are provided in an RFID interface for connection to the RFID readers.

6. The time slot allocation apparatus according to claim 5, wherein the RFID interface controls the RFID readers and collects identification codes of the RFID tags read by the RFID readers.

7. The time slot allocation apparatus according to claim 1, wherein each of the time slot allocation device and the collision prevention device further comprises an RFID reader management unit for allocating time slots to respective RFID readers using information about the RFID readers, which is input through the RFID interface for connection to the RFID readers.

8. The time slot allocation apparatus according to claim 7, wherein the RFID interface is provided to connect the RFID readers to respective components included in RFID middleware in which the RFID reader management unit is included.

9. The time slot allocation apparatus according to claim 8, wherein the RFID middleware comprises:

the RFID interface provided to connect the RFID readers to respective components included in the RFID middleware;

the RFID reader management unit connected through the RFID interface and configured to allocate time slots for communication to the RFID readers to prevent collisions from occurring between the time slots;

an RFID tag information management unit connected through the RFID interface and configured to collect and manage the identification codes of the RFID tags read by the RFID readers; and

an application interface provided to connect the RFID middleware to a central server for controlling the RFID network.

10. The time slot allocation apparatus according to claim 1, wherein no RFID reader is interposed between an arbitrary RFID reader and an RFID reader adjacent to the RFID reader.

11. A time slot allocation method for preventing collisions between time slots in a Time Division Multiple Access (TDMA)-based Radio Frequency Identification (RFID) network, the method allocating time slots, obtained by dividing a same frequency band into unit time slots, to RFID readers for reading identification codes of RFID tags in the TDMA-based RFID network, comprising:

a first step of causing a time slot allocation device, which allocates time slots for communication with the RFID tags to a plurality of RFID readers provided in the RFID network, to allocate an arbitrary time slot to an arbitrary RFID reader;

a second step of allocating a time slot to an RFID reader adjacent to the arbitrary RFID reader so that a collision prevention device allocates a time slot, which is different from the arbitrary time slot and is non-successive to the arbitrary time slot, to the adjacent RFID reader in order to eliminate temporal interference between respective RFID readers provided in the RFID network; and

a third step of allocating time slots to the arbitrary RFID reader and the adjacent RFID reader so that a certain number of time slots is interposed between the time slots allocated to the arbitrary RFID reader and the adjacent RFID reader in order to read a moving RFID tag.

12. The time slot allocation method according to claim 11, wherein, at the third step, the certain number is 3 to 6.

13. The time slot allocation method according to claim 11, wherein the third step comprises a step of repeating the second and third steps until time slots are allocated to all RFID readers provided in the RFID network.

14. The time slot allocation method according to claim 11, wherein the collision prevention device enables the number of time slots allocated to all RFID readers provided in the RFID network to be minimized.

15. The time slot allocation method according to claim 11, wherein, at the second step, the non-successive time slot is a time slot implemented such that one to four time slots are interposed between the time slots allocated to the arbitrary RFID reader and the adjacent RFID reader in order to prevent temporal interference between the allocated time slots.