Method for Card-Reading Anti-Collision with Automatic Frequency Hopping

A radio frequency identification system for card-reading anti-collision with automatic frequency hopping, the system comprising:

• a card reader configured to read multiple cards;
• wherein the card reader and the multiple cards have capabilities of automatic frequency-sweeping and/or of hopping from a current channel to another channel, and have capabilities of storing access addresses and transaction addresses;
• wherein when the card reader is in a frequency-hopping card-seeking state, it is in an n-channel frequency hopping working state, in which the access address of each channel is the same, and the card reader reads the multiple cards by means of hopping frequencies in a sequence iteratively through n channels;
• and
• wherein:
• A. when the card reader works at one of the n channels, the card reader first checks if any card responds;
• if yes, the card reader proceeds to Step B;
• if no, the card reader proceeds to Step E;
• B. the card reader checks whether two or more cards collide or conflict;
• if yes, the card reader proceeds to Step C;
• if only one card is being read, the card reader proceeds to Step D;
• C. the card reader issues a command of random frequency hopping, commanding all the conflicting cards to hop to other channels of the n channels and wait to access those channels, and proceeds to Step E;
• D. the only card being read and the card reader read transaction addresses and carry out a transaction communication;
• after the transaction is completed, the card reader proceeds to Step E;
• and
• E. the card reader hops to a next channel of the n channels in the sequence, and proceeds to Step A.