System, apparatus and method for synchronizing communications between devices

• US 9,735,831 B1
• Filed: 09/22/2009
• Issued: 08/15/2017
• Est. Priority Date: 09/22/2009
• Status: Active Grant

• Current Assignee: Ademco Inc. (Resideo Technologies, Inc.)
• Original Assignee: Honeywell International Inc.
• Inventors: Juntunen, Robert, Nichols, Steven, Kidder, Kenneth
• Primary Examiner(s): Chacko, Joe
• Application Number:
  US12/564,682
• Time in Patent Office: 2,884 Days
• Field of Search: 709248
• CPC Class Codes: H04B 1/713 using frequency hopping
• CPC Class Codes: H04B 1/7156 Arrangements for sequence synchronisation
• CPC Class Codes: H04B 2001/71563 Acquisition
• CPC Class Codes: H04J 3/0658 Clock or time synchronisation among packet nodes
• CPC Class Codes: H04J 3/0667 Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays arrangements for monitoring round trip delays in packet switching networks H04L43/0864
• CPC Class Codes: H04W 56/00 Synchronisation arrangements

Abstract

Systems, apparatuses and methods for synchronizing communication actions between multiple communication devices by accounting for discrepancies between timing functionality in communicating devices. A time value indicative of a remote device'"'"'s view of current time is received. Where it is determined that the time value differs from a locally generated view of current time by at least an established amount, the range of time in which communications signals with the remote device will be monitored and transmitted is extended.

Claims

1. A method comprising:

receiving, at a local device during a first communication window, a time value indicative of a remote device'"'"'s view of current time, wherein the first communication window has a first duration during which communication signals can be communicated between the remote device and the local device to synchronize a frequency hopping sequence that is used for communication between the remote device and the local device;

determining, at the local device, that the time value differs from a locally generated view of current time by at least an established amount;

in response to the determination, establishing an extended communication window during which communications signals can be communicated between the remote device and the local device to synchronize the frequency hopping sequence that is used for communication between the remote device and the local device, wherein the extended communication window has a second duration that is longer than the first duration;

wherein after establishing the extended communication window;

initiating monitoring for incoming signals from the remote device during the extended communication window and at a time earlier than the first communication window would begin;

discontinuing monitoring for incoming signals from the remote device at or before an end of the extended communication window and at a time later than the first communication window would end;

initiating transmission of a message for outgoing signals to the remote device during the extended communication window and at a time earlier than the first communication window would begin; and

discontinuing transmission of the message to the remote device at or before the end of the extended communication window and at a time later than the first communication window would end.

2. The method of claim 1, wherein the extended communication window begins earlier than the first communication window would begin.

3. The method of claim 1, wherein the extended communication window ends later than the first communication window would end.

4. The method of claim 1, wherein the extended communication window begins earlier than the first communication window would begin and ends later than the first communication window would end.

5. The method of claim 1, wherein receiving the time value comprises receiving a representation of a current time generated by a local timer of the remote device.

6. The method of claim 1, wherein determining that the time value differs from a locally generated view of current time comprises:

comparing the received time value to the locally generated view of current time, and

determining whether a difference between the received time value and the locally generated view of current time is at least the established amount.

7. The method of claim 6, wherein the difference between the received time value and the locally generated view of current time is a result of at least a deviation between local clock circuitry and remote clock circuitry of the remote device.

8. The method of claim 1, further comprising creating the locally generated view of current time using values from a timer local to a device that receives the time value from the remote device.

9. A method comprising:

periodically receiving at a client device synchronization messages originating at a remote device, wherein the synchronization messages including a time value corresponding to the remote device'"'"'s representation of current time and a synchronization time value corresponding to the time at which a next synchronization message will be sent by the remote device;

if a predetermined number of the synchronization messages are received at the client device during a first communication window, monitoring at the client device for incoming messages from the remote device and transmitting outgoing messages from the client device to the remote device during the first communication window in accordance with a frequency hopping sequence;

if the predetermined number of the synchronization messages are not received at the client device during the first communication window, monitoring at the client device for incoming messages from the remote device and transmitting outgoing messages from the client device to the remote device during a second communication window, wherein the second communication window has a duration that is longer than the first communication window and wherein the second communication window begins before the first communication window would begin and ends after the first communication window would end;

wherein monitoring at the client device for incoming messages from the remote device during the second communication window comprises;

initiating monitoring for incoming messages from the remote device at a time earlier than the first communication window would begin;

discontinuing monitoring for incoming messages from the remote device at a time later than the first communication window would end;

wherein transmitting outgoing messages from the client device to the remote device during the second communication window comprises;

initiating transmission of an outgoing message to the remote device at a time earlier than the first communication window would begin; and

discontinuing transmission of the outgoing message to the remote device at a time later than the first communication window would end.

10. The method of claim 9, further comprising determining whether the predetermined number of the synchronization messages are consecutively received, and wherein:

if the predetermined number of the synchronization messages are consecutively received at the client device during the first communication window, monitoring at the client device for incoming messages from the remote device and transmitting outgoing messages from the client device to the remote device during the first communication window in accordance with the frequency hopping sequence; and

if the predetermined number of the synchronization messages are not consecutively received at the client device during the first communication window, monitoring at the client device for incoming messages from the remote device and transmitting outgoing messages from the client device to the remote device during the second communication window.

11. The method of claim 9, further comprising adjusting a local timer at the client device to account for timing differences between the client device and the remote device.

12. The method of claim 9, further comprising returning to monitoring for the incoming messages and transmitting the outgoing messages during the first communication window when the client device determines that the predetermined number of the synchronization messages are again consecutively received at the client device.

13. An apparatus comprising:

a local timer configured to generate a local representation of current time;

a receiver configured to wirelessly receive a remote device'"'"'s representation of current time during a first communication window with a first duration in which communication signals with the remote device are communicated to synchronize a frequency hopping sequence with the remote device; and

circuitry configured to compare the local and remote representations of current time, and in response to determining that the local and remote representations of current time differ by at least a predetermined amount, establishing an extended communication window with a second duration in which communications signals with the remote device will be communicated to synchronize a frequency hopping sequence with the remote device, wherein the second duration is longer than the first duration; and

wherein after establishing an extended communication window, the circuitry configured to;

initiate monitoring for incoming signals from the remote device during the extended communication window and at a time earlier than the first communication window would begin;

discontinuing monitoring for incoming signals from the remote device at or before an end of the extended communication window and at a time later than the first communication window would end;

initiating transmission of a message for outgoing signals to the remote device during the extended communication window and at a time earlier than the first communication window would begin; and

discontinuing transmission of the message to the remote device at or before the end of the extended communication window and at a time later than the first communication window would end.

14. The apparatus as in claim 13, further comprising a sleep control module configured to awaken the apparatus for communication during the extended communication window.

15. A system comprising:

(a) a remote device comprising;

means for generating a remote representation of current time; and

a transmitter configured to wirelessly transmit a time value indicative of the remote representation of current time;

(b) a local device comprising;

means for generating a local representation of current time;

a receiver coupled to wirelessly receive the time value from the remote device; and

circuitry configured to compare the time value and the local representation of current time, and in response to determining that the time value and the local representation of current time differ by at least a predetermined amount, extending the duration of a range of time in which communications signals with the remote device will be communicated to synchronize a frequency hopping sequence with the remote device; and

wherein extending the duration of the range of time comprises;

initiating monitoring for incoming signals at a time earlier than an expected monitoring start time as determined from the locally generated view of current time;

discontinuing monitoring of the incoming signals at a time later than an expected monitoring termination time as determined from the locally generated view of current time;

initiating transmission of a message for outgoing signals at a time earlier than an expected transmission start time as determined from the locally generated view of current time; and

discontinuing transmission of the message at a time later than an expected transmission termination time as determined from the locally generated view of current time.