Methods and apparatus for fast and energy-efficient light recovery in a visible light communication (VLC) system

Patent metadata

Field	Value
Publication number	US-RE47182-E
Application number	US-201514984814-A
Country	US
Kind code	E1
Filing date	Dec 30, 2015
Priority date	Jul 31, 2009
Publication date	Dec 25, 2018
Grant date	Dec 25, 2018

Abstract

A visible light communication (VLC) device is provided for use in a VLC system. The VLC device detect a trigger condition indicating a failure of a VLC link associated with first allocated resources used to communicate with a second VLC device. In response to the detection, the VLC device terminates on the first allocated resources transmission of data to the second VLC device and transmits a fast link recovery (FLR) signal using the first allocated resources. The VLC device receives a fast link recovery response (FLR RSP) signal indicating the second VLC device received the FLR signal and, in response, the VLC device resumes transmission of data to the second VLC device.

First claim

What is claimed is:

1. For use in a visible light communication (VLC) system, a method of link recovery comprising:
in a first VLC device, communicating with a second device on a VLC link associated with at least one first band among a plurality of bands;
in the first VLC device, detecting a trigger condition indicating a failure of the VLC link associated with the at least one first band;
in the first VLC device, in response to detection of the trigger condition, terminating transmission of data on the at least one first band to the second VLC device;
in the first VLC device, transmitting a plurality of fast link recovery (FLR) signals on free bands from among all of the plurality of bands;
in the first VLC device, receiving at least one fast link recovery response (FLR RSP) signal on a subset of the plurality of bands, the subset different from the at least one first band, the at least one FLR RSP signal indicating that the second VLC device received the FLR signals; and
in response to reception of the at least one FLR RSP signal, resuming in the first VLC device transmission of data to the second VLC device on at least one of the subset of bands on which the at least one FLR RSP signal was received.

2. The method as set forth in claim 1 , wherein the first VLC device is one of:
an access point of a network infrastructure,
a mobile node operable to access an access point of a network infrastructure, and
a mobile node operable to communicate with another mobile node.

3. The method as set forth in claim 2 , wherein the trigger condition is one of:
failure to receive in the first VLC device a predetermined number of ACK signals transmitted by the second VLC device,
receipt in the first VLC device of a predetermined number of consecutive NACK signals transmitted by the second VLC device,
failure to receive in the first VLC device at least one of an ACK signal and a NACK signal transmitted by the second VLC device during a predetermined time period,
receipt of consecutive messages containing errors from the second VLC device, and
determining that channel quality of the VLC link is below a threshold.

4. The method as set forth in claim 2 , comprising:
in the first VLC device, transmitting to the second VLC device first battery status information associated with a battery of the first VLC device; and
in the first VLC device, receiving from the second VLC device second battery status information associated with a battery of the second VLC device.

5. The method as set forth in claim 4 , wherein the first VLC device transmits the FLR signals only if the first battery status and the second battery status indicate that a battery life of the first VLC device is longer than a battery life of the second VLC device.

6. The method as set forth in claim 5 , wherein if the first battery status and the second battery status indicate that the battery life of the first VLC device is not longer than the battery life of the second VLC device:
the first VLC device does not transmit the FLR signals to the second VLC device, and
the first VLC device receives an incoming FLR signal from the second VLC device.

7. The method as set forth in claim 2 , wherein the plurality of bands comprises a plurality of available color bands.

8. The method as set forth in claim 1 , wherein the subset of bands on which the at least on FLR RSP signal was received comprises at least two color bands.

9. The method as set forth in claim 8 , wherein resuming in the first VLC device transmission of data to the second VLC device on the at least one of the subset of bands comprises resuming transmission on one of the at least two color bands.

10. The method as set forth in claim 2 , wherein transmitting the FLR signals comprises transmitting from the first VLC device the plurality of FLR signals in a plurality of directions.

11. The method as set forth in claim 10 , wherein receiving the at least one FLR RSP signal comprises receiving in the first VLC device the at least one FLR RSP signal transmitted by the second VLC device in at least one of the plurality of directions.

12. The method as set forth in claim 11 , wherein resuming in the first VLC device transmission of data to the second VLC device comprises resuming transmission on a selected one of the at least one of the plurality of directions.

13. For use in a visible light communication (VLC) system, a A first VLC visible light communication (VLC) device in a VLC system, the first VLC device comprising:
a mobile node; and
a transceiver within the mobile node configured to: communicate with a second device on a VLC link associated with at least one first band among a plurality of bands;
wherein the mobile node is configured to detect a trigger condition indicating a failure of the VLC link associated with the at least one first band; in response to the detection,and terminate, on the at least one first band, transmission of data to thea second VLC device;in response to the detection,
wherein the transceiver is further configured to
transmit a plurality of a fast link recovery (FLR) signals on free bands from among all of the plurality of bands;, and
receive at least one fast link recovery response (FLR RSP) signal from a subset of the plurality of bands, wherein the subset is different from the at least one first band, the at least one FLR RSP signal indicating the second VLC device received the PLR FLR signals;, and

in response to reception of the at least one FLR RSP signal,wherein the mobile node is further configured to resume transmission of data to the second VLC device on at least one of the subset of bands on which the at least one of FLR RSP signal was received in response to reception of the at least one FLR RSP signal.

14. The first VLC device as set forth in claim 13 , wherein the first VLC device is one of:
an access point of a network infrastructure, and
a mobile node operable to access an access point of a network infrastructure, and
a mobile node operable to communicate with another mobile node.

15. The first VLC device as set forth in claim 14 , wherein the trigger condition is one of:
failure to receive in the first VLC device a predetermined number of ACK signals transmitted by the second VLC device,
receipt in the first VLC device of a predetermined number of consecutive NACK signals transmitted by the second VLC device,
failure to receive in the first VLC device at least one of an ACK signal and a NACK signal transmitted by the second VLC device during a predetermined time period,
receipt of consecutive messages containing errors from the second VLC device, and
determining that channel quality of the VLC link is below a threshold.

16. The first VLC device as set forth in claim 14 , wherein the first VLC device is further configured to transmit to the second VLC device first battery status information associated with a battery of the first VLC device and to receive from the second VLC device second battery status information associated with a battery of the second VLC device.

17. The first VLC device as set forth in claim 16 , wherein the first VLC device transmits the FLR signals only if the first battery status and the second battery status indicate that the battery life of the first VLC device is longer than the battery life of the second VLC device.

18. The first VLC device as set forth in claim 17 , wherein if the first battery status and the second battery status indicate that the battery life of the first VLC device is not longer than the battery life of the second VLC device, th

Assignees

• Samsung Electronics Co Ltd
• Samsung Electronics Co Ltd

Inventors

• Li Ying
• Rajagopal Sridhar

Classifications

• H04W76/19 Primary

  Connection re-establishment · CPC title

• H04B10/116 Primary

  Visible light communication · CPC title

• H04B10/0777

  Monitoring line amplifier or line repeater equipment · CPC title

• H04B10/0797

  Monitoring line amplifier or line repeater equipment · CPC title

• H04B10/03

  Arrangements for fault recovery · CPC title