Time slot allocation apparatus and method for preventing collisions between time slots in TDMA-based RFID network
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
H04Q-005/22
H04L-012/43
출원번호
US-0064739
(2007-11-16)
등록번호
US-8325017
(2012-12-04)
우선권정보
KR-10-2007-0096781 (2007-09-21)
국제출원번호
PCT/KR2007/005775
(2007-11-16)
§371/§102 date
20080225
(20080225)
국제공개번호
WO2009/038247
(2009-03-26)
발명자
/ 주소
Jo, Geun Sik
Park, Seung Bo
Yu, Young Hoon
출원인 / 주소
INHA-Industry Partnership Institute
대리인 / 주소
H.C. Park & Associates, PLC
인용정보
피인용 횟수 :
0인용 특허 :
8
초록▼
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 readin
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.
대표청구항▼
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 re
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 configured to allocate time slots required for communication with the RFID tags to a plurality of RFID readers provided in the RFID network; anda collision prevention device configured to perform control such that the time slot allocation device allocates time slots to the plurality of RFID readers while distributing different and non-sequential time slots to adjacent RFID readers, thus preventing collisions from occurring between time slots allocated to the RFID readers,wherein the collision prevention device perform the control by using a first constraint, a second constraint and a third constraint,wherein the first constraint indicates that at least two RFID readers, which are sets of variables having time slots, don't use the same time slot as long as the at least two RFID readers are not spaced sufficiently far apart among the at least two RFID readers,wherein the second constraint indicates that non-sequential time slots are selected among time slots allocated to adjacent RFID readers,wherein the third constraint indicates that time slots are selected non-sequentially but as adjacently as possible among time slots allocated to adjacent RFID readers, andwherein the second constraint is given in the following: |tsi−tsj|≧d(d≅2)where tsi represents an arbitrary time slot allocated to an arbitrary RFID reader of the at least two RFID readers, tsj represents a different time slot from the time slot tsi that is allocated to another of the at least two RFID readers adjacent to the arbitrary RFID reader, and is non-sequential to the time slot tsi, and d represents the number of time slots interposed between allocated time slots tsi and tsj. 2. The time slot allocation apparatus according to claim 1, wherein the collision prevention device is configured to perform 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 is configured to perform 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 is configured to enable 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 is configured to control the RFID readers and collect 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 configured to allocate time slots to respective RFID readers using information about the RFID readers, which is input through an RFID interface for connection to the RFID readers. 8. The time slot allocation apparatus according to claim 7, wherein the RFID interface is configured 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; andan 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 the arbitrary RFID reader and the RFID reader adjacent to the arbitrary 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) allocating, using a time slot allocation device that allocates the time slots for communication with the RFID tags to a plurality of RFID readers provided in the RFID network, an arbitrary time slot to an arbitrary RFID reader; and(b) allocating a time slot to an RFID reader adjacent to the arbitrary RFID reader using a collision prevention device to allocate the time slot that is different from the arbitrary time slot and is non-sequential 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,wherein allocating time slots to the arbitrary RFID reader and the adjacent RFID reader comprises allocating so that a 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,wherein allocating time slots to the arbitrary RFID reader and the adjacent RFID reader further comprises using a first constraint, a second constraint and a third constraint,wherein the first constraint indicates that at least two RFID readers do not use the same time slot as long as the at least two RFID readers are not spaced sufficiently far apart among the at least two RFID readers,wherein the second constraint indicates that non-sequential time slots are selected among time slots allocated to adjacent RFID readers,wherein the third constraint indicates that time slots are selected non-sequential but as adjacently as possible among time slots allocated to adjacent RFID readers, andwherein the second constraint is given in the following: |tsi−tsj|≧d(d≅2)where tsi represents the arbitrary time slot allocated to the arbitrary RFID reader, tsj represents the time slot allocated to the adjacent RFID reader, and d represents the number of time slots interposed between allocated time slots tsi and tsj. 12. The time slot allocation method according to claim 11, wherein the number of time slots is 3 to 6. 13. The time slot allocation method according to claim 11, further comprising repeating (a) and (b) 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 the non-successive time slot is a time slot implemented such that two 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.
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이 특허에 인용된 특허 (8)
Sekiya Kunihiko,JPX ; Nitta Katsumi,JPX ; Karasawa Hirobumi,JPX ; Okano Michiaki,JPX ; Kuma Katsuhiko,JPX ; Iwasaki Kazunori,JPX ; Uehara Kensuke,JPX ; Hashimoto Satoru,JPX, Information identification system for identifying response units by a control unit, and the control unit and the response units for the information identification system.
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