System, apparatus and method for synchronizing communications between devices

Patent metadata

Field	Value
Publication number	US-9735831-B1
Application number	US-56468209-A
Country	US
Kind code	B1
Filing date	Sep 22, 2009
Priority date	Sep 22, 2009
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

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.

First claim

What is claimed is:

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

Assignees

• Juntunen Robert
• Nichols Steven
• Kidder Kenneth
• Honeywell Int Inc

Inventors

• Juntunen Robert
• Nichols Steven
• Kidder Kenneth

Classifications

• H04B1/713

  using frequency hopping · CPC title

• H04B1/7156 Primary

  Arrangements for sequence synchronisation · CPC title

• H04J3/0667

  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 title

• H04J3/0658

  Clock or time synchronisation among packet nodes · CPC title

• H04B2001/71563

  Acquisition · CPC title