METHODS FOR PROLONGING BATTERY LIFE IN TOLL TRANSPONDERS

• US 20140132398A1
• Filed: 10/14/2013
• Published: 05/15/2014
• Est. Priority Date: 11/15/2012
• Status: Active Grant

• Current Assignee: Kapsch TrafficCom AG (Datax Handelsgmbh)
• Original Assignee: Kapsch TrafficCom AG (Datax Handelsgmbh)
• Inventors: Turnock, Richard, Malarky, Alastair, He, Weimin
• Granted Patent: US 9,911,015 B2
• Time in Patent Office: Days
• US Class Current: 340/10.4
• CPC Class Codes: G06K 7/10207 parameter settings related to power consumption of the interrogator
• CPC Class Codes: G07B 15/063 using wireless information transmission between the vehicle and a fixed station identification of vehicles G08G

Abstract

A transponder, such as an electronic toll transponder, is configured to recognize when it is being subjected to consistent and repeated trigger signals over an extended period of time and, in response, the transponder enters a reduced-responsiveness state. In the reduced-responsiveness state, the transponder may only intermittently respond to detected trigger signals. The transponder may recognize when the repeated trigger signal situation has been resolved and then return to normal responsiveness.

Claims

1. A method of managing battery life of a toll transponder, the method implemented by the toll transponder comprising:

repeatedly detecting trigger signals and sending a response signal in reply to each trigger signal; and

determining that a threshold parameter has been reached during the repeatedly detecting and, based on that determination, entering a reduced-responsiveness state during which some detected trigger signals are ignored.

2. The method of claim 1, wherein the threshold parameter comprises a maximum number of trigger signals in a first time window.

3. The method of claim 1, wherein the threshold parameter comprises a maximum time since receipt of a first trigger signal and during which subsequent trigger signals are consistently received within a threshold time value of each other.

4. The method of claim 3, wherein said repeatedly detecting comprises:

starting a first timer on detection of the first trigger signal;

detecting and responding to the subsequent trigger signals; and

while detecting and responding to subsequent trigger signals, determining that the time elapsed between successive trigger signals does not exceed the threshold time value.

5. The method of claim 4, wherein said determining that a threshold parameter has been reached comprises determining that the first timer has exceeded said maximum time.

6. The method of claim 4, further comprising:

zeroing the first timer if the time elapsed between successive trigger signals exceeds the threshold time value, and restarting the first timer when a next trigger signal is received.

7. The method of claim 4, wherein said repeatedly detecting further comprises:

restarting a second timer on receipt of each trigger signal, and wherein the second timer measures the time since receipt of a most recent trigger signal, and wherein the second timer is compared to the threshold time value.

8. The method of claim 1, wherein entering the reduced-responsiveness state comprises:

cyclically,

ignoring detected trigger signals and sending no response signal during a silence period, and

detecting one or more trigger signals after the silence period and sending a response signal to each of the one or more trigger signals.

9. The method of claim 8, wherein said cyclically ignoring and detecting comprises:

starting the silence period;

detecting trigger signals during the silence period and sending no response signal;

determining that the silence period has expired;

sending the response signal in response to one or more subsequently detected trigger signals; and

repeating the starting, detecting that the silence period has expired, determining that the silence period has expired, and sending provided trigger signals continue to be detected within a threshold time value of each other.

10. The method of claim 9, wherein said determining that the silence period has expired comprises one of:

determining that a maximum number of trigger signals have been ignored during the silence period; and

determining that a silence period duration has elapsed.

11. The method of claim 8, further comprising:

if a trigger signal is not detected within a threshold time value of a previous trigger signal, cancelling a cycle of ignoring and detecting and returning to the operation of repeatedly detecting a trigger signal and sending a response signal in reply to each trigger signal.

12. A transponder, comprising an antenna, an RF transceiver, a power source, a processor, and memory, and wherein the processor is configured to:

repeatedly detect trigger signals and to send a response signal in reply to each trigger signal; and

determine that a threshold parameter has been reached during the repeatedly detecting and, based on that determination, enter a reduced-responsiveness state during which some detected trigger signals are ignored.

13. The transponder of claim 12, wherein the threshold parameter comprises a maximum number of trigger signals in a first time window.

14. The transponder of claim 12, wherein the threshold parameter comprises a maximum time since receipt of a first trigger signal and during which subsequent trigger signals are consistently received within a threshold time value of each other.

15. The transponder of claim 14, wherein the processor is configured to repeatedly detect by:

starting a first timer on detection of the first trigger signal;

detecting and responding to the subsequent trigger signals; and

while detecting and responding to subsequent trigger signals, determining that the time elapsed between successive trigger signals does not exceed the threshold time value.

16. The transponder of claim 15, wherein the processor is configured to determine that a threshold parameter has been reached by determining that the first timer has exceeded said maximum time.

17. The transponder of claim 15, wherein the processor is further configured to zero the first timer if the time elapsed between successive trigger signals exceeds the threshold time value, and restart the first timer when a next trigger signal is received.

18. The transponder of claim 15, wherein the processor is configured to repeatedly detect by restarting a second timer on receipt of each trigger signal, and wherein the second timer measures the time since receipt of a most recent trigger signal, and wherein the second timer is compared to the threshold time value.

19. The transponder of claim 12, wherein the processor is configured to enter the reduced-responsiveness state by:

cyclically,

ignoring detected trigger signals and sending no response signal during a silence period, and

detecting one or more trigger signals after the silence period and sending a response signal in reply to each of the one or more trigger signals.

20. The transponder of claim 19, wherein cyclically ignoring and detecting comprises:

starting the silence period;

detecting trigger signals during the silence period and sending no response signal;

determining that the silence period has expired;

sending the response signal in response to one or more subsequently detected trigger signals; and

repeating the starting, detecting, determining, and sending provided trigger signals continue to be detected within a threshold time value of each other.

21. The transponder of claim 20, wherein determining that the silence period has expired comprises one of:

determining that a maximum number of trigger signals have been ignored during the silence period; and

determining that a silence period duration has elapsed.

22. The transponder of claim 19, wherein the processor is further configured to, if a trigger signal is not detected within a threshold time value of a previous trigger signal, cancel the cycle of ignoring and detecting and return to the operation of repeatedly detecting a trigger signal and sending a response signal in reply to each trigger signal.