Patent ID: 8325017
Filing Date: 2012-12-04
Classification: H04W

Abstract:
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; and a 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, and wherein the second constraint is given in the following: where ts