System for time synchronization of audio devices

Patent metadata

Field	Value
Publication number	US-9979998-B1
Application number	US-201715584873-A
Country	US
Kind code	B1
Filing date	May 2, 2017
Priority date	May 2, 2017
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

Described are techniques for synchronizing multiple devices within a group to enable performance of a synchronized action through the exchange of time data. A first device provides a timestamp or other time data to multiple other devices via a multicast transmission. Each of the other devices determines a time at which the timestamp was received and exchanges this data with one another. Based on the determined times, the other devices may be synchronized relative to a selected synchronization master device. One of the other devices may then determine a from the first device, and determine the time at which the timestamp from the first device was received, enabling the first device to be synchronized with the synchronization master device. Devices that are unable to receive multicast transmissions from the first device may exchange timestamps with the first device via an access point.

First claim

What is claimed is:

1. A system comprising:
a first audio device;
a second audio device;
a third audio device, wherein the first audio device is configured to provide audio data to the second audio device and the third audio device via multicast transmissions;
one or more memories storing computer-executable instructions; and
one or more hardware processors to execute the computer-executable instructions to:
send, by the first audio device, first time data to the second audio device and the third audio device via a multicast transmission;
determine, by the second audio device, second time data indicative of a time at which the first time data was received by the second audio device;
determine, by the third audio device, third time data indicative of a time at which the first time data was received by the third audio device;
send, by the third audio device, the first time data and the third time data to the second audio device;
determine, by the second audio device, that the first time data generated by the first audio device corresponds to the first time data received from the third audio device;
determine, by the second audio device, first offset data indicative of a difference between the second time data and the third time data;
send, by the second audio device, a first request for time data to the first audio device;
determine, by the second audio device, fourth time data indicative of a time at which the first request was sent by the second audio device;
determine, by the first audio device, fifth time data indicative of a time at which the first request was received;
send, by the first audio device, the fifth time data to the second audio device;
determine, by the second audio device, sixth time data indicative of a time at which the fifth time data was received;
determine, by the second audio device, second offset data indicative of a difference between the fourth time data and the fifth time data and a difference between the fifth time data and the sixth time data;
determine, based on the first offset data and the second offset data, third offset data indicative of a difference between the first time data and the third time data; and
output audio using the first audio device, the second audio device, and the third audio device, wherein a first timing of audio output of the third audio device is based on the third offset data and a second timing of audio output of the second audio device is based on the second offset data.

2. The system of claim 1 , further comprising computer-executable instructions to:
send, by the second audio device, the first time data and the second time data to the third audio device;
wherein the first offset data is determined by each of the second audio device and the third audio device.

3. The system of claim 1 , further comprising computer-executable instructions to:
determine, by the third audio device, a plurality of the first time data and a plurality of the third time data over a period of time;
subsequent to the period of time, provide the plurality of the first time data and the plurality of the third time data from the third audio device to the second audio device; and
provide an indication of the third offset data from the second audio device to the third audio device.

4. The system of claim 1 , further comprising:
a fourth audio device;
an access point in communication with the first audio device and the fourth audio device; and
computer-executable instructions to:
send, by the fourth audio device, a second request for time data to the first audio device;
determine, by the fourth audio device, seventh time data indicative of a time at which the second request was sent;
determine, by the first audio device, eighth time data indicative of a time at which the first audio device received the second request;
send, by the first audio device, the eighth time data to the fourth audio device;
determine, by the fourth audio device, ninth time data indicative of a time that the eighth time data was received by the fourth audio device;
determine, using the fourth audio device, fourth offset data indicative of a difference between the seventh time data and the eighth time data and a difference between the eighth time data and the ninth time data; and
output the audio using the fourth audio device, wherein a third timing of audio output using the fourth audio device is based on the fourth offset data.

5. A method comprising:
determining first time data indicative of a time at which an event associated with a first device is detected by a second device;
determining second time data indicative of a time at which the event is detected by a third device;
determining first offset data based on a difference between the first time data and the second time data;
sending, by the second device, a request to the first device;
determining, by the second device, third time data indicative of a time at which the request was sent to the first device;
sending, by the first device to the second device, fourth time data indicative of a time at which the request was received by the first device;
determining fifth time data indicative of a time at which the second device received the fourth time data;
determining second offset data based on one or more differences between the third time data, the fourth time data, and the fifth time data; and
causing the first device, the second device, and the third device to perform a synchronized action, wherein a first timing associated with the second device is based on the first offset data and a second timing associated with the third device is based on the first offset data and the second offset data.

6. The method of claim 5 , wherein the event includes receiving, by the second device and the third device, sixth time data, from the first device, via a multicast transmission, wherein the sixth time data is indicative of a time at which the sixth time data was sent, and wherein the determining of the first offset data further includes:
determining that the time indicated by the sixth time data received by the first device corresponds to the time indicated by sixth time data received by the second device; and
based on the correspondence between the sixth time data received by the first device and the sixth time data received by the second device, determining that the first time data is associated with the second time data.

7. The method of claim 5 , further comprising sending one or more of the fourth time data or the sixth time data to the first device and the third device, wherein the first offset data is further determined based in part on the one or more of the fourth time data or the sixth time data.

8. The method of claim 5 , further comprising:
sending the first time data to the third device; and
sending the second time data to the second device;
wherein the first offset data is determined by each of the first device and the second device.

9. The method of claim 5 , further comprising:
sending, by the second device, the second time data to the third device, wherein the second time data includes a first timestamp indicative of a time at which the first time data was transmitted by the first device and a second timestamp indicative of a time at which the first time data was received by the second device; and
sending, by the third device, the third time data to the second device, wherein the third time data includes the first timestamp and a third timestamp indicative of a time at which the first time data was received by the third device;
wherein the determining the first offset data includes:
determining that the first timestamp received by the second device corresponds to the first timestamp received by th

Assignees

• Amazon Tech Inc

Inventors

• Pogue Michael Alan
• Haight Kyle Gordon

Classifications

• G11B27/10

  Indexing; Addressing; Timing or synchronising; Measuring tape travel · CPC title

• H04N21/43615

  Interfacing a Home Network, e.g. for connecting the client to a plurality of peripherals (home Audio Video Interoperability [HAVI] data switching networks H04L12/2805) · CPC title

• H04L12/2807

  Exchanging configuration information on appliance services in a home automation network (arrangements for maintenance or administration involving network analysis for automatically determining the actual topology of a network H04L41/12; hardware or software tools for network management using graphical user interfaces H04L41/22; address allocation H04L61/50) · CPC title

• H04N21/8547

  involving timestamps for synchronizing content · CPC title

• H04N21/43637

  involving a wireless protocol, e.g. Bluetooth®, RF or wireless LAN [IEEE 802.11] (arrangements for wireless networking or broadcasting of information in indoor or near-field type systems H04B10/114) · CPC title