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

• US 20110210828A1
• Filed: 05/06/2011
• Published: 09/01/2011
• Est. Priority Date: 11/06/2008
• Status: Active Grant

• Current Assignee: Nationz Technologies Inc.
• Original Assignee: Nationz Technologies Inc.
• Inventors: Liu, Jianhui, Sun, Yingtong
• Granted Patent: US 8,698,601 B2
• Time in Patent Office: Days
• US Class Current: 340/10.2
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10069 the collision being resolved in the frequency domain, e.g. by hopping from one frequency to the other frequency hopping or spread spectrum techniques H04B7/00
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02

Abstract

A method for card-reading anti-collision with automatic frequency hopping is provided, which is used for a system in which a card reader simultaneously reads a plurality of cards in radio frequency identification technologies. The method comprises: both the card reader and the cards to be read are configured to have an automatic frequency-sweep function and a function of hopping from a current channel to another channel, and to store access addresses and transaction addresses; 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 cards by means of hopping frequencies in a sequence iteratively through n channels. When the card reader detects that two or more cards collide, the card reader sends a command of random frequency hopping, making all the conflicting cards to hop to other channels randomly and to wait to access those channels. The beneficial effects of said method includes: it can quickly realize a card-reading anti-collision mechanism and improve the card-reading speed.

Claims

1. A card-reading anti-collision method with automatic frequency hopping for a radio frequency identification system that includes a card reader reading multiple cards, the method comprising:

A. when the card reader works at one of n channels, checking via the card reader if any card responds;

if yes, proceeding to Step B;

if no, proceeding to Step E;

B. checking via the card reader whether two or more cards collide or conflict;

if yes, proceeding to Step C;

if only one card is being read, proceeding to Step D;

C. issuing via the card reader 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 proceeding to Step E;

D. reading transaction addresses and carrying out a transaction communication at the card reader and the only card being read;

after the transaction is completed, proceeding to Step E; and

E. hopping at the card reader to a next channel of the n channels in a sequence, and proceeding to Step A;

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, and

when the card reader is in a frequency-hopping card-seeking state, the card reader 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 the n channels.

2. The card-reading anti-collision method of claim 1, wherein:

the access address is used to differentiate different systems, and the access address in a same system is the same.

3. The card-reading anti-collision method of claim 1, wherein the transaction address occurs at a stage after the card reader accesses the card to be read to differentiate different stages in a same system.

4. 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.

5. The radio frequency identification system of claim 4, wherein:

the access address is used to differentiate different systems, and the access address in a same system is the same.

6. The radio frequency identification system of claim 4, wherein the transaction address occurs at a stage after the card reader accesses the card to be read to differentiate different stages in a same system.