Wireless synchronization based on beacons

Patent metadata

Field	Value
Publication number	US-2016262120-A1
Application number	US-201514788330-A
Country	US
Kind code	A1
Filing date	Jun 30, 2015
Priority date	Mar 4, 2015
Publication date	Sep 8, 2016
Grant date	—

Abstract

A circuit includes a processor to store a beacon timestamp generated from a wireless network. An output port controlled by the processor causes an interrupt that initiates a capture of a link layer timestamp relative to the beacon timestamp. An input port on the processor receives the link layer time stamp. A synchronizer captures a processor timestamp relative to the beacon timestamp and determines a time offset value relative to the received link layer time stamp by computing a difference between the processor timestamp and the link layer timestamp. The time offset value is combined with the processor timestamp to synchronize the processor with respect to the beacon timestamp.

First claim

What is claimed is:

1 . A circuit comprising:
a processor to store a beacon timestamp generated from a wireless network; an output port controlled by the processor to cause an interrupt that initiates a capture of a link layer timestamp relative to the beacon timestamp; an input port on the processor to receive the link layer time stamp; and a synchronizer to capture a processor timestamp relative to the beacon timestamp and determine a time offset value relative to the received link layer time stamp by computing a difference between the processor timestamp and the link layer timestamp, wherein the time offset value is combined with the processor timestamp to synchronize the processor with respect to the beacon timestamp.

2 . The circuit of claim 1 , wherein the time offset value is added to or subtracted from the processor timestamp to synchronize the processor with respect to the beacon timestamp.

3 . The circuit of claim 1 , further comprising a link layer that generates an interrupt in response to the output port, the interrupt causes the link layer to capture the link layer timestamp relative to the beacon timestamp.

4 . The circuit of claim 3 , wherein the link layer further comprises a link layer output port to transmit the link layer time stamp to the input port on the processor.

5 . The circuit of claim 3 , wherein the beacon timestamp includes the time that the beacon was received by the link layer and a beacon sequence number, where the time offset value is combined with the beacon sequence number by the processor to form a starting command for an application.

6 . The circuit of claim 5 , further comprising an application layer that is controlled by the processor, the application layer utilizes the starting command to synchronize operations of an application with at least one other application operating across the wireless network on a wireless device.

7 . The circuit of claim 6 , wherein the application and the at least one other application are a synchronized wireless audio application having at least two speakers that are synchronized to receive wireless audio data at a time relative to the same beacon sequence number and time offset value that is about the same period in time.

8 . The circuit of claim 6 , wherein the application and the at least one other application are a synchronized wireless controller application having at least two slave devices that are synchronized to receive wireless control data from a master control device at a time relative to the same beacon sequence number and time offset value that is about the same period in time.

9 . The circuit of claim 6 , wherein the application and the at least one other application are a synchronized wireless video application having at least two video devices that are synchronized to receive wireless video data at a time relative to the same beacon sequence number and time offset value that is about the same period in time.

10 . A system comprising:
a link layer to receive a beacon timestamp from a wireless network; a processor to receive the beacon timestamp from the link layer; an output port controlled by the processor to cause an interrupt at the link layer to initiate a capture of a link layer timestamp at the link layer relative to the beacon timestamp; an input port on the processor to receive the link layer time stamp from the link layer in response to the interrupt at the link layer; and a synchronizer to capture a processor timestamp relative to the beacon timestamp and determine a time offset value relative to the received link layer time stamp from the link layer by computing a difference between the processor timestamp and the link layer timestamp, wherein the time offset value is combined with the processor timestamp to synchronize the processor with respect to the beacon timestamp received at the link layer.

11 . The system of claim 10 , wherein the time offset value is added to or subtracted from the processor timestamp to synchronize the processor with respect to the beacon timestamp received at the link layer.

12 . The system of claim 10 , wherein the link layer further comprises a link layer output port to transmit the link layer time stamp to the input port on the processor.

13 . The system of claim 10 , wherein the beacon timestamp includes the time that the beacon was received by the link layer and a beacon sequence number, where the time offset value is combined with the beacon sequence number by the processor to form a starting command for an application.

14 . The system of claim 13 , further comprising an application layer that is controlled by the processor, the application layer utilizes the starting command to synchronize operations of an application with at least one other application operating across the wireless network on a wireless device.

15 . The system of claim 14 , wherein the application and the at least one other application are a synchronized wireless audio system having at least two speakers that are synchronized to receive wireless audio data at a time relative to the same beacon sequence number and time offset value that is about the same period in time.

16 . The system of claim 14 , wherein the application and the at least one other application are a synchronized wireless controller system having at least two slave devices that are synchronized to receive wireless control data from a master control device at a time relative to the same beacon sequence number and time offset value that is about the same period in time.

17 . The system of claim 14 , wherein the application and the at least one other application are a synchronized wireless video system having at least two video devices that are synchronized to receive wireless video data at a time relative to the same beacon sequence number and time offset value that is about the same period in time.

18 . The system of claim 10 , wherein the beacon timestamp is generated by a wireless access point.

19 . A method comprising:
receive a beacon timestamp from a wireless network; generating an interrupt to initiate a capture of a link layer timestamp relative to the beacon timestamp; capturing a processor timestamp relative to the beacon timestamp; and determining a time offset value relative to the link layer time stamp by computing a difference between the processor timestamp and the link layer timestamp, wherein the time offset value is combined with the processor timestamp to synchronize at least two wireless devices operating on the wireless network.

20 . The method of claim 19 , wherein the beacon timestamp includes the time that the beacon was received by a link layer and a beacon sequence number, where the time offset value is combined with the beacon sequence number by the processor to form a starting command for an application.

Assignees

• Texas Instruments Inc

Inventors

• Shani Oren
• Mishol Guy
• Weinrib Uri

Classifications

• H04W56/001 Primary

  Synchronization between nodes · CPC title

• H04W88/08

  Access point devices · CPC title

• H04W40/244

  using a network of reference devices, e.g. beaconing · CPC title

• H04W84/12

  WLAN [Wireless Local Area Networks] · CPC title