1. Field of the Invention
The present disclosure relates to a Radio Frequency Identification (referred to as ‘RFID’, hereinafter) system capable of removing a transmission leakage signal.
2. Description of the Related Art
Generally, an RFID system is widely used in a system for transmitting and receiving information in a variety of fields such as approval management, document management, distribution management, identification and radio authentication, which includes a plurality of tags on which tag information is recorded and a reader to read tag information included in the tag.
The plurality of tags in the same radio frequency field in such an RFID system are activated by the reader and, the tags transmit their own tag information to the reader causing a collision in the plurality of tag information.
Accordingly, in order to solve the above described problem, the reader periodically transmits an anti-collision period that is a time when each tag can send the tag information, so as to prevent the plurality of tag information from colliding among them.
Meanwhile, in order to isolate a transmission signal from a receiving signal in an RFID system in which a radio signal is transmitted and received together, a separate isolation device such as an isolator is used.
Since there occurs a phenomenon in which the reader cannot receive a receiving signal well due to the fact that a portion of a transmission signal is leaked and mixed into the receiving signal while the transmission signal is transmitted and a receiving signal is received, the reader includes a separate leakage canceller to cancel such a transmission leakage signal, so that it performs an adjustment task to generate a cancellation signal.
However, while a set condition of the leakage signal canceller should be changed to cancel the transmission leakage signal that changes according to an RF environment when an RF environment having tags installed therein changes, a reader controller to control a reader in the RFID system in the art is engaged only in a task to read the tag during an anti-collision period so that there occurs a problem that the set condition cannot be changed according to a change of the RF environment.
Further, once a set condition is set in a leakage signal canceller, since the set condition is constantly remained until the anti-collision period finishes, there was a limitation to suitably counteract a market requirement according to a change of RF environment.