Method and apparatus for dynamically-tuned communication with one among myriad tags

• US 20070120649A1
• Filed: 08/07/2006
• Published: 05/31/2007
• Est. Priority Date: 09/23/2005
• Status: Active Grant

• Current Assignee: Visible Assets Incorporated (NOV, Inc.)
• Original Assignee: Visible Assets Incorporated (NOV, Inc.)
• Inventors: Waterhouse, Paul, Stevens, John, Tarcoci, Florin
• Granted Patent: US 8,659,396 B2
• Time in Patent Office: Days
• US Class Current: 340/10.200
• 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 7/10039 interrogator driven, i.e. synchronous
• 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: G06K 7/10316 using at least one antenna particularly designed for interrogating the wireless record carriers antennas in general H01Q1/22
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil

Abstract

An area-reading antenna (in RF linkage with myriad RF tags) is dynamically tuned. It may be dynamically tuned as to its transmission of a power/clock field, or dynamically tuned as to its transmission of a data signal, or dynamically tuned as to its reception of a data signal, or some combination of all three. In this way, a base station has an improved ability to communicate with a greater fraction of the RF tags within its reading area, despite detuning of individual tags due to proximity of detuning influences such as metal or liquids.

Claims

1. A method for use with a base station comprising a tunable antenna and myriad RF tags nearby, the method comprising the steps of:

transmitting a power/clock field from the antenna at a first frequency below 1 MHz, thereby providing power and clock to a plurality of the RF tags;

while the power/clock field is being transmitted, first transmitting a data signal from the antenna at a second frequency, the second frequency higher than the first frequency and below 1 MHz, and receiving a response from at least a first one of the RF tags at the antenna while not receiving a response from at least a second one of the RF tags;

tuning the antenna differently than during the first transmitting;

while the power/clock field is being transmitted, for a second time transmitting a data signal from the antenna at the second frequency, and receiving a response from the at least a second one of the RF tags at the antenna.

2. The method of claim 1 further characterized in that the first and second frequencies are both below 450 kHz.

3. The method of claim 1 where the tuning of the antenna yielding the response from the at least a second one of the RF tags is based upon stored information regarding tuning that previously yielded a response from the at least a second one of the RF tags.

4. The method of claim 1 wherein the first transmitting also does not receive a response from at least a third one of the RF tags, and wherein the second transmitting also does not receive a response from the at least a third one of the RF tags, the method further comprising the steps of;

tuning the antenna differently than during the first transmitting and differently than during the second transmitting;

while the power/clock field is being transmitted, for a third time transmitting a data signal from the antenna at the second frequency, and receiving a response from the at least a third one of the RF tags at the antenna.

5. A method for use with a base station comprising first and second tunable antennas and myriad RF tags nearby, the method comprising the steps of:

transmitting a power/clock field from the first antenna at a first frequency below 1 MHz, thereby providing power and clock to a plurality of the RF tags;

while the power/clock field is being transmitted, first transmitting a data signal from the second antenna at a second frequency, the second frequency higher than the first frequency and below 1 MHz, and receiving a response from at least a first one of the RF tags at the second antenna while not receiving a response from at least a second one of the RF tags;

tuning the second antenna differently than during the first transmitting;

while the power/clock field is being transmitted, for a second time transmitting a data signal from the second antenna at the second frequency, and receiving a response from the at least a second one of the RF tags at the second antenna.

6. The method of claim 5 further characterized in that the first and second frequencies are both below 450 kHz.

7. The method of claim 5 where the tuning of the antenna yielding the response from the at least a second one of the RF tags is based upon stored information regarding tuning that previously yielded a response from the at least a second one of the RF tags.

8. The method of claim 5 wherein the first transmitting also does not receive a response from at least a third one of the RF tags, and wherein the second transmitting also does not receive a response from the at least a third one of the RF tags, the method further comprising the steps of;

tuning the second antenna differently than during the first transmitting and differently than during the second transmitting;

while the power/clock field is being transmitted, for a third time transmitting a data signal from the second antenna at the second frequency, and receiving a response from the at least a third one of the RF tags at the second antenna.

9. A method for use with a base station comprising a tunable antenna and myriad independently powered RF tags nearby, the method comprising the steps of:

first transmitting a data signal from the antenna at a frequency, the frequency below 1 MHz, and receiving a response from at least a first one of the independently powered RF tags at the antenna while not receiving a response from at least a second one of the independently powered RF tags;

tuning the antenna differently than during the first transmitting;

while the power/clock field is being transmitted, for a second time transmitting a data signal from the antenna at the frequency, and receiving a response from the at least a second one of the independently powered RF tags at the antenna.

10. The method of claim 9 further characterized in that the frequency is below 450 kHz.

11. The method of claim 9 where the tuning of the antenna yielding the response from the at least a second one of the independently powered RF tags is based upon stored information regarding tuning that previously yielded a response from the at least a second one of the independently powered RF tags.

12. The method of claim 9 wherein the first transmitting also does not receive a response from at least a third one of the independently powered RF tags, and wherein the second transmitting also does not receive a response from the at least a third one of the independently powered RF tags, the method further comprising the steps of;

tuning the antenna differently than during the first transmitting and differently than during the second transmitting;

for a third time transmitting a data signal from the antenna at the frequency, and

receiving a response from the at least a third one of the independently powered RF tags at the antenna.