Access point synchronization in Wi-Fi fire detection systems

• US 9,036,489 B2
• Filed: 06/22/2012
• Issued: 05/19/2015
• Est. Priority Date: 06/22/2012
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honey International Incorporated
• Inventors: Huseth, Steve, Gonia, Patrick, Berezowski, Andrew G., Kolavennu, Soumitri
• Primary Examiner(s): Ghowrwal, Omar
• Assistant Examiner(s): BROCKMAN, ANGEL T
• Application Number:
  US13/531,266
• Publication Number:
  US 20130343202A1
• Time in Patent Office: 1,061 Days
• Field of Search: 370/244, 370/338
• US Class Current: 370/244
• CPC Class Codes: G08B 17/00 Fire alarms; Alarms responsive to explosion
• CPC Class Codes: G08B 25/009 Signalling of the alarm condition to a substation whose identity is signalled to a central station, e.g. relaying alarm signals in order to extend communication range
• CPC Class Codes: G08B 25/10 using wireless transmission systems G08B25/009 takes precedence
• CPC Class Codes: G08B 29/181 due to failing power supply
• CPC Class Codes: H04W 4/90 Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 52/0206 in access points, e.g. base stations access point devices per se H04W88/08
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0296 switching to a backup power supply
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Systems and methods of backup battery support for switches and access points in fire detection systems are provided. Methods can include identifying a communications time interval for a plurality of devices, detecting a power failure, identifying a start time for a next scheduled communications time interval for a respective one of the plurality of devices, placing a wireless access point in a low power mode, and, substantially immediately prior to the start time, removing the wireless access point from the low power mode.

Claims

1. A method comprising:

a wireless access point wirelessly communicating with a plurality of devices that are part of a fire system and at least one appliance that is not part of the fire system;

the wireless access point identifying a communications time interval for the plurality of devices of the fire system;

the wireless access point detecting a power failure;

the wireless access point identifying a start time for a next scheduled communications time interval for a respective one of the plurality of devices;

a processor of the wireless access point placing the wireless access point in a low power mode; and

prior to the start time, a processor of the wireless access point removing the wireless access point from the low power mode, wherein during power failure, the wireless access point only handles messages from devices of the fire system and ignores messages from the at least one appliance that are is not part of the fire system.

2. The method of claim 1 further comprising, after removing the wireless access point from the low power mode, receiving a status or alarm message from the respective one of the plurality of devices.

3. The method of claim 2 further comprising, after receiving the status or alarm message, transmitting an acknowledgement message to the respective one of the plurality of devices.

4. The method of claim 3 further comprising, after transmitting the acknowledgement message, replacing the wireless access point in the low power mode.

5. The method of claim 1 further comprising:

identifying an end time for the next scheduled communications time interval for the respective one of the plurality of devices; and

after the end time, replacing the wireless access point in the low power mode.

6. The method of claim 1 further comprising ignoring a message received outside of the next scheduled communications time interval or ignoring a non-essential message received within the next scheduled communications time interval.

7. The method of claim 1 wherein placing the wireless access point in the low power mode includes using less power from a backup battery than used when removed from the low power mode.

18. The method of claim 1 wherein at least one of the plurality of devices is capable of detecting the presence of a fire.

8. A wireless access point comprising:

a transceiver that wirelessly communicates with a plurality of devices of a fire system and at least one appliance that is not part of the fire system;

control circuitry;

a programmable processor; and

executable control software stored on a non-transitory computer readable medium for;

identifying a communications time interval for the plurality of devices of the fire system associated with the transceiver;

detecting a power failure;

identifying a start time for a next scheduled communications time interval for a respective one of the plurality of devices;

placing at least one of the transceiver and the programmable processor in a low power mode; and

substantially immediately prior to the start time, removing the at least one of the transceiver and the programmable processor from the low power mode, wherein during power failure, the transceiver only handles messages from fire system devices and ignores messages from the at least one appliance that are is not part of the fire system.

9. The wireless access point of claim 8 wherein the transceiver includes an 802.11 radio adapted to communication compliant with an IEEE 802.11 standard.

10. The wireless access point of claim 8 further comprising a backup battery for providing power to the transceiver and the programmable processor during the power failure.

11. The wireless access point of claim 8 wherein, after removing the at least one of the transceiver and the programmable processor from the low power mode, the transceiver receives a status or alarm message from the respective one of the plurality of devices.

12. The wireless access point of claim 11 wherein, after the transceiver receives the status or alarm message, the transceiver transmits an acknowledgement message to the respective one of the plurality of devices.

13. The wireless access point of claim 12 further comprising executable control software stored on the non-transitory computer readable medium for replacing the wireless access point in the low power mode after the transceiver transmits the acknowledgement message.

14. The wireless access point of claim 8 further comprising executable control software stored on the non-transitory computer readable medium for identifying an end time for the next scheduled transmission time interval for the respective one of the plurality of devices and for replacing the wireless access point in the low power mode substantially immediately after the end time.

15. A system comprising:

at least one wireless access point that communicates with a plurality of devices of a fire system and at least one appliance that is not part of the fire system; and

at least one monitoring device of the plurality of devices of the fire system that wirelessly communicates with a control panel of the fire system through the at least one wireless access point, wherein the at least one wireless access point stores information related to scheduled communications time intervals for the at least one monitoring device;

wherein, when the at least one wireless access point detects a power failure, the at least one wireless access point identifies a start time for a next scheduled communications time interval and enters a low power mode, and wherein, prior to the start time, the at least one wireless access point exits the low power mode, wherein during power failure, the wireless access point only handles messages from monitoring devices of the fire system and ignores messages from the at least one appliance that are is not part of the fire system.

16. The system of claim 15 wherein, after exiting the low power mode, the at least one access point receives an alarm or status message from the at least one monitoring device, wherein, after receiving the alarm or status message, the at least one access point transmits an acknowledgement message to the at least one monitoring device, and wherein, after transmitting the acknowledgement message, the at least one access point reenters the low power mode.

17. The system of claim 15 wherein the at least one access point identifies an end time for the next scheduled transmission communications time interval and reenters the low power mode substantially immediately after the end time for the next scheduled transmission time interval.

19. The system of claim 15 further comprising at least two wireless access points, wherein each of the at least two wireless access points stores information related to the scheduled communications time intervals for the at least one monitoring device, wherein, when each of the at least two wireless access points detects the power failure, each of the at least two wireless access points identifies the start time for the next scheduled communications time interval and enters the low power mode, and wherein, prior to the start time of the next scheduled communications time interval, each of the at least two wireless access points exits the low power mode.

20. The system of claim 15 further comprising at least two monitoring devices, wherein a first of the at least two monitoring devices functions as a parent to a second of the at least two monitoring devices, wherein the first of the at least two monitoring devices stores information related to scheduled communications time intervals for the second of the at least two monitoring devices, wherein, when each of the at least two monitoring devices detects the power failure, each of the at least two monitoring devices identifies a start time for the next scheduled communications time interval for the second of the at least two monitoring devices and enters the low power mode, and wherein, prior to the start time, each of the at least two monitoring devices exits the low power mode.