Method for selecting one or more transponders

• US 20050024186A1
• Filed: 07/30/2004
• Published: 02/03/2005
• Est. Priority Date: 08/01/2003
• Status: Active Grant

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Germany GmbH (Microchip Technology Incorporated)
• Inventors: Friedrich, Ulrich
• Granted Patent: US 7,336,154 B2
• Time in Patent Office: Days
• US Class Current: 340/10.310
• CPC Class Codes: G06K 17/00 Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
• 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 7/10049 binary tree

Abstract

One or more transponders are selected by a base station out of a plurality of transponders. For this purpose an identification bit sequence (IB) that is or includes a random number bit sequence (ZB) is made available in the respective transponder and the base station transmits in a bit-by-bit fashion a selection bit sequence (AB) to the transponders. These sequences (IB or ZB) and (AB) are compared bit-by-bit in the respective transponder. The comparing is performed by way of a predeterminable comparing criterion to provide a comparing result in the form of a selection bit to which a bit value is assigned. The selection is then made depending on the bit value of the selection bit of the respective transponder.

Claims

1. A method for selecting one or more transponders from a plurality of transponders by a base station, said method comprising the following steps:

a) generating in each transponder of said plurality of transponders a random number bit sequence,

b) providing in each of said plurality of transponders an identification bit sequence including said random number bit sequence,

c) transmitting in bit-by-bit fashion a selection bit sequence from said base station to said plurality of transponders,

d) comparing in bit-by-bit fashion in each of said transponders bits of said selection bit sequence with corresponding bits of said identification bit sequence using a predeterminable comparing criterion, to provide a comparing result,

e) allocating to a transponder selection bit for each transponder a value according to said comparing result, and

f) selecting one or more transponders depending on the value of their transponder selection bits.

2. The method of claim 1, further comprising transmitting said predeterminable comparing criterion from said base station (BS) to said transponders (TR1, TR2 . . . ).

3. The method of claim 2, further comprising making said comparing criterion dependent on a bit position of the bits to be compared which are bits of the identification bit sequence (IB) and bits of the selection bit sequence (AB).

4. The method of claim 1, further comprising selecting said comparing criterion as an arithmetic operator.

5. The method of claim 4, wherein said arithmetic operator is selected as any one of a larger-operator, a smaller-operator and an equal-operator.

6. The method of claim 1, wherein said identification bit sequence (IB) comprises a static bit sequence portion which is assigned to said transponders (TR1, TR2) when said transponders are manufactured.

7. The method of claim 1, further comprising repeatedly performing said selection process, and omitting transponders that have been selected in a preceding selection process from any further selection process.

8. The method of claim 7, further comprising generating in a transponder still participating in a second or further selection process, a new random number bit sequence (ZB) and including said new random number bit sequence in said identification bit sequence (IB).

9. The method of claim 1, further comprising causing a respective transponder (TR1, TR2) to transmit said value of the corresponding bit of its identification bit sequence (IB) to the base station prior to said bit-by-bit comparing of the respective bits of its identification bit sequence with the bits of said selection bit sequence (AB).

10. The method of claim 8, further comprising adjusting said selection bit sequence (AB) in said base station (BS) depending on one or more identification bit sequences received by said base station from said transponders.

11. The method of claim 1, further comprising inserting said random number bit sequence in any area of said identification bit sequence.

12. The method of claim 11, further comprising inserting said random number bit sequence at the beginning of said identification bit sequence.

13. The method of claim 1, comprising using said random number bit sequence (ZB) exclusively as said identification bit sequence.