Patent ID: 8610544
Filing Date: 2013-12-17
Classification: H04W

Abstract:
1. A method for determining an optimal frame size for tag collision prevention in a radio frequency identification (RFID) system in which frame sizes limited to a certain unit are used to identify a plurality of tags, the method comprising the steps of: (a) calculating, by an RFID reader, an estimated frame size value which minimizes expected time delay per tag, the RFID reader identifying the tags and calculating the estimated frame size value in accordance with the following equation: (wherein “e” represents an Euler's constant, represents a Lambert omega function, “*+” represents a floor function, and “r” represents a rate obtained by dividing a time delay of an idle slot by a time delay of a collision slot); (b) calculating, by the RFID reader, expected time delays per tag of a left-hand frame size which is smaller than and closest to the estimated frame size value, and a right-hand frame size which is greater than and closest to the estimated frame size value; (c) comparing, by the RFID reader, the expected time delay per tag of the left-hand frame size with that of the right-hand frame size; and (d) determining, by the RFID reader, a frame size which has a smaller expected time delay per tag, between the left-hand frame size and the right-hand frame size, to be an optimal frame size.