APPARATUS AND METHOD USING HISTOGRAM-BASED TECHNIQUES FOR AVOIDING OVERPOLLING

• US 20110090063A1
• Filed: 10/20/2010
• Published: 04/21/2011
• Est. Priority Date: 10/21/2009
• Status: Abandoned Application

• Current Assignee: Savi Technology Incorporated
• Original Assignee: Savi Technology Incorporated
• Inventors: Zmrzli, Miroslav, KOONS, DAVID BRUCE
• Application Number:
  US12/908,641
• Publication Number:
  US 20110090063A1
• Time in Patent Office: Days
• US Class Current: 340/10.33
• CPC Class Codes: G06K 7/10009 sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves

Abstract

A device including an RF transceiver coupled to receive signals from an antenna; and a micro-controller coupled to the RF transceiver periodically scanning for a wakeup signal and measuring a signal strength is provided. The micro-controller may use the signal strength to update a count value in a bin of a histogram. The micro-controller may also decrement histogram values periodically, and direct the RF transceiver to respond to the wakeup signal if the count value in the histogram is lower than a threshold value. Further according to some embodiments disclosed herein a system for avoiding over polling in wireless communications may include a tag and a reader. The reader may transmit a wakeup signal periodically and the tag may operate as the device disclosed above. Also, a method for using a device and a system as above is provided.

Claims

1. A device comprising:

an RF transceiver coupled to receive signals from an antenna; and

a micro-controller coupled to the RF transceiver periodically scanning for a wakeup signal and measuring a signal strength;

wherein

the micro-controller uses the signal strength to update a count value in a bin of a histogram, the micro-controller decrements histogram values periodically, and

directs the RF transceiver to respond to the wakeup signal if the count value in the histogram is lower than a threshold value.

2. The device of claim 1 further comprising:

a timer circuit and a power management circuit to deliver power coupled to the RF transceiver and the micro-controller; and

wherein

the micro-controller circuit regulates the power delivered by the power management circuit using the wake-up signal and a signal from the timer circuit.

3. The device of claim 2 wherein the power delivered by the power management circuit is selected from the group consisting of a low power value (sleep power) and a high power value (turn on power).

4. The device of claim 3 wherein the RF transceiver is turned on periodically to look for wakeup signals from the reader;

the RF transceiver is turned on by wakeup pulses provided by the micro-controller; and

the period to turn on the RF transceiver is provided by the timer circuit.

5. The device of claim 3 wherein the power management circuit delivers a turn on power to the RF transceiver and the micro-controller for a period of time provided by the timer circuit.

6. The device of claim 1 wherein a wakeup period is obtained for the time lapsed between the receipt of two consecutive wakeup signals.

7. The device of claim 6 wherein the period to decrement the histogram values is determined by the micro-controller using the wakeup period and provided by the timer circuit to the power management circuit.

8. The device of claim 7 wherein the wakeup period is obtained by using a counter to count the wake up pulses provided to the RF transceiver;

and

the counter is returned to zero when it exceeds the period to decrement the histogram values.

9. The device of claim 1 wherein:

a plurality of count values is stored so that each count value corresponds to a range of signal strengths measured by the micro-controller;

each received wakeup signal is associated with the range of signal strengths, incrementing the count value associated with that range to create the histogram; and

the device responds to the wakeup signal by providing power to the RF transceiver and the micro-controller for a period of time.

10. The device of claim 1 wherein the RF transceiver is an ultra-high frequency (UHF) transceiver.

11. A system for avoiding over polling in wireless communications comprising a tag and a reader such that:

the reader transmits a wakeup signal periodically;

the tag receives the wakeup signal from the reader and measures a signal strength;

the system uses the signal strength to update a count value in a bin of a histogram;

the histogram values are decremented periodically; and

the tag responds to the wakeup signal if the count value in the histogram is lower than a threshold value.

12. A method for using a device comprising the steps of:

receiving a wakeup signal using an RF transceiver;

measuring the signal strength using a micro-controller;

using a signal strength to update a count value in a bin of a histogram;

decrementing the histogram values periodically; and

responding to the wakeup signal from the reader using the RF transceiver if the count value in the histogram is lower than a threshold value.

13. The method of claim 12 wherein:

the device also comprises a timer circuit and a power management circuit to deliver power coupled to the transceiver and the micro-controller; and

the micro-controller circuit regulates the power delivered by the power management circuit using the wakeup signal and a signal from the timer circuit.

14. The method of claim 13 further comprising the step of obtaining a wakeup period for the time lapsed between the receipt of two consecutive wakeup signals.

15. The method of claim 14 wherein the step of decrementing the histogram values is performed in a period determined by the micro-controller using the wakeup period, and provided by the timer circuit to the power management circuit.

16. The method of claim 14 wherein the step of obtaining a wakeup period is performed by using a counter to count the wakeup pulses received by the RF transceiver;

and

the counter is returned to zero when it exceeds the period to decrement the histogram values.

17. The method of claim 12 wherein the RF transceiver is a UHF transceiver.

18. A method for avoiding over polling in wireless communications between a tag and a reader comprising the steps of:

sending wakeup signals periodically using the reader;

receiving the wakeup signal from the reader using the tag;

measuring a signal strength using the tag;

using the signal strength to update a count value in a bin of a histogram;

decrementing the histogram values periodically; and

responding to the wakeup signal from the reader using the tag if the count value in the histogram is lower than a threshold value.