Method for preventing reader collision, method for driving an rfid reader using the method and rfid reader for performing the method

A method for driving an RFID reader, the method comprising:

• allowing a target reader to access to a tag to communicate the tag, when a present time slot of the target reader in RFID readers is identical with a time slot ID which represent a performance sequence in one frame;
• and
• performing a reader collision-preventing algorithm, when the target reader and other reader simultaneously access to the tag or when the target reader are interfered by other reader,
• wherein performing the reader collision-preventing algorithm, comprises:
• detecting the number of readable readers within a readable region of the target reader;
• calculating the number of peripheral readers within the readable region and a collision region of the target reader by using the number of the readable readers;
• forming one frame with time slots of which the number equals to the number of the peripheral readers;
• and
• setting a present time slot of the target reader to be one of the time slots, the one being selected randomly in the time slots.

A radio frequency identification (RFID) reader capable of preventing a first interference that happens when more than one RFID reader accesses to one tag and a second interference that happens directly between RFID readers, comprising:

• a transmitting section transmitting an RF transmitting signal through an antenna;
• a receiving section receiving an RF receiving signal from the tag through the antenna;
• a main control section controlling the transmitting section to generate the RF transmitting signal and processing information of the tag, which is contained in the RF receiving signal;
• and
• a collision-preventing section forming one frame with time slots of which the number is equal to the number of peripheral readers within a collision region when the first or second interference happens, and setting a present time slot of a target reader to be one of the time slots, the one being selected randomly in the time slots.