LATENCY MITIGATION

• US 20150244484A1
• Filed: 06/06/2014
• Published: 08/27/2015
• Est. Priority Date: 02/25/2014
• Status: Active Grant

• Current Assignee: Qualcomm technologies international, ltd. (Qualcomm, Inc.)
• Original Assignee: Cambridge Silicon Radio Limited (Qualcomm, Inc.)
• Inventors: Tyson, Hugo Mark, Graube, Nicolas Guy Albert, Heydon, Robin
• Granted Patent: US 9,692,538 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04J 3/0661 using timestamps
• CPC Class Codes: H04L 12/2827 Reporting to a device within the home network; wherein the reception of the information reported automatically triggers the execution of a home appliance functionality
• CPC Class Codes: H04L 2012/2841 Wireless
• CPC Class Codes: H04W 28/021 in wireless networks with changing topologies, e.g. ad-hoc networks self-organizing networks H04W84/18
• CPC Class Codes: H04W 4/38 for collecting sensor information
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 56/001 Synchronization between nodes
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A network including a plurality of wireless communication devices capable of operating according to a wireless protocol that imposes no common timebase at the network level, the plurality of devices comprising: an initiator device configured to detect an event and in response transmit an event message having a payload comprising a time field; and a set of appliance devices configured to receive and automatically retransmit messages received from others of the devices, each appliance device being associated with an appliance supplementary to its wireless communication function and being configured to, on receiving an event message comprising a time field, cause their respective associated appliance to perform a function at a time indicated by the content of the time field in the received message.

Claims

1. A network including a plurality of wireless communication devices capable of operating according to a wireless protocol that imposes no common timebase at the network level, the plurality of devices comprising:

an initiator device configured to detect an event and in response transmit an event message having a payload comprising a time field; and

a set of appliance devices configured to receive and automatically retransmit messages received from others of the devices, each appliance device being associated with an appliance supplementary to its wireless communication function and being configured to, on receiving an event message comprising a time field, cause their respective associated appliance to perform a function at a time indicated by the content of the time field in the received message.

2. A network as claimed in claim 1, wherein each event message comprises one or more other data fields and each appliance device is configured to cause its respective associated appliance to perform a function only if those other fields in the received message meet one or more predefined criteria.

3. A network as claimed in claim 1, wherein one or more of the appliance devices comprise a clock, and each of those appliance devices is configured to, on receiving an event message, perform the steps of:

determining a time when it is to retransmit the event message;

form a new time value by subtracting from the time signified by the time field in the received event message the difference as indicated by the clock between the time when that appliance device received the event message and the time when it is to retransmit the event message; and

retransmit the event message with its time field signifying the new time value.

4. A network as claimed in claim 3, wherein the clock is normally stopped and each of those appliance devices is configured to, on receiving an event message, perform the step of starting the clock.

5. A network as claimed in claim 3, wherein those appliance devices are configured to cause their respective associated appliance to perform a function at a time indicated by the content of the time field in the received message as measured by their respective clock.

6. A network as claimed in claim 1, wherein one or more of the appliance devices is configured for reading the time from a clock source external to the respective appliance device, and each of those appliance device is configured to, cause their respective associated appliance to perform a function at a time indicated by the external clock.

7. A network as claimed in claim 6, wherein those appliance devices are configured to access the external clock by receiving wireless signals from the clock.

8. A network as claimed in claim 7, wherein the devices are configured to communicate time accessed from an external clock using time differences for adjusting their local time definition.

9. A network as claimed in claim 1, wherein the wireless communication devices operate according to the Bluetooth Low Energy protocol.

10. A network as claimed in claim 1, wherein the initiator device is configured to detect the operation of a user interface device and in response transmit the event message.

11. A network as claimed in claim 1, wherein the appliances are lighting appliances.

12. A network as claimed in claim 1, wherein at least some of the appliance devices are sited at locations that are out of range of transmissions from the initiator device.

13. A network as claimed in claim 1, wherein the network is a mesh network.

14. A network as claimed in claim 1, wherein the network is an ad-hoc network.

15. A network as claimed in claim 1, comprising a set of devices configured to receive and automatically retransmit messages received from other of the devices;

each message having a payload comprising a time field; and

each device being configured to determine whether to retransmit a message received by it in dependence on one or more of;

an indication of a maximum hop count contained in the received message;

a determination that the device had received the same message before; and

the content of the time field in the message.

16. A wireless communication device configured to receive and automatically retransmit messages received from other devices by means of a wireless protocol that imposes no common timebase at the network level, the wireless communication device being associated with an appliance supplementary to its wireless communication function and being configured to, on receiving an event message comprising a time field, cause its respective associated appliance to perform a function at a time indicated by the content of the time field in the received message.

17. A wireless communication device, as in claim 16, configured to determine whether to retransmit a message received by it in dependence on one or more of:

an indication of a maximum hop count contained in the received message;

a determination that the device had received the same message before; and

the content of the time field in the message.