# US 2023/0058596 A1 · Lifi power management

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- Number: US 2023/0058596 A1
- Document ID: US20230058596A1
- Status: Published application
- Kind: A1
- Application number: 17/790,909
- Filed: 2021-01-08
- Published: 2023-02-23
- Earliest claimed: 2020-01-13
- Assignees: Signify Holding B.V.
- Applicants: Signify Holding B.V.
- Inventors: Matthias WENDT; Karnekumar ARULANDU
- Web page: https://patentgrep.com/patent/US20230058596A1

## CPC

- H04B 10/116: Visible light communication
- H04B 10/114: Indoor or close-range type systems
- H04B: TRANSMISSION

## Abstract

A node (200) is provided for use in a LiFi system (100) to provide LiFi signals to an endpoint device (130). The node (200) comprises a visible light source (220) for emitting modulated visible light and non-modulated visible light to provide illumination, and an infrared light source (210) for emitting modulated infrared light. The node (200) is configured to output a LiFi signal at a first one or more frequencies via the infrared light source (210) for reception by said endpoint device (130). In response to receiving input to provide illumination, the node (200) turns on the visible light source (220) to provide said illumination and automatically transfers an output of the LiFi signal from the infrared light source (210) to the visible light source (220) by outputting the LiFi signal at said first one or more frequencies via the visible light source (220) for reception by said endpoint device (130), and turning off the infrared light source (210).

## Claims

### Claim 1

A node for use in a LiFi system to provide LiFi signals to at least one endpoint device, the node comprising:
a visible light source for emitting modulated visible light and non-modulated visible light to provide illumination; and
an infrared light source for emitting modulated infrared light;
wherein the node is configured to:
output a LiFi signal at a first one or more frequencies via the infrared light source for reception by said at least one endpoint device; and
wherein the node is configured to, in response to receiving input to provide illumination, when transmitting the LiFi signal via the infrared light source, turn on the visible light source to provide said illumination and automatically transfer an output of the LiFi signal from the infrared light source to the visible light source by:
outputting the LiFi signal at said first one or more frequencies via the visible light source for reception by said at least one endpoint device;
outputting at least one of a first indication via at least one of the infrared light source and a second indication via the visible light source, wherein the first indication and the second indication indicate that output of the LiFi signal will be transferred to the visible light source; and
turning off the infrared light source.

### Claim 2 (depends on 1)

The node according to claim 1, wherein the automatic transferring of said output of the LiFi signal comprises outputting the first indication using the infrared light source prior to outputting the LiFi signal at said first one or more frequencies via the visible light source and turning off the infrared light source.

### Claim 3 (depends on 1)

The node according to claim 1, wherein the automatic transferring of said output of the LiFi signal comprises outputting both the first indication via the infrared light source, and the second indication via the visible light source prior to turning off the infrared light source.

### Claim 4 (depends on 1)

The node according to claim 1, wherein the node is configured to, in response to receiving a request for a high-speed LiFi signal, output the high-speed LiFi signal at a second one or more frequencies via the infrared light source, the second one or more frequencies comprising one or more frequencies higher than the first one or more frequencies.

### Claim 5 (depends on 4)

The node according to claim 4, wherein the visible light source has a maximum modulation frequency, the first one or more frequencies being below the maximum modulation frequency and the second one or more frequencies being above the maximum modulation frequency.

### Claim 6 (depends on 1)

The node according to claim 1, wherein the visible light source comprises a white LED having a phosphor coating.

### Claim 7 (depends on 1)

The system comprising a plurality of nodes according to claim 1.

### Claim 8 (depends on 7)

The system according to claim 7, comprising a user-operable switch constructed and arranged to generate said input for use by one or more of the plurality of nodes in response to operation by a user.

### Claim 9 (depends on 7)

The system according to claim 7, comprising a presence sensor constructed and arranged to generate said input for use by one or more of the plurality of nodes in response to detecting presence of a user.

### Claim 10 (depends on 7)

The system according to claim 7, wherein each of the nodes is configured to output the same LiFi signal at the first one or more frequencies via the respective visible light source.

### Claim 11 (depends on 7)

The system according to claim 7, comprising a controller configured to:
determine at least one of the nodes as being within range of the endpoint device;
control the determined at least one node to output the LiFi signal.

### Claim 12 (depends on 11)

The system according to claim 11, wherein the controller is configured to turn off all nodes other than the determined at least one node.

### Claim 13 (depends on 11)

The system according to claim 11, wherein controlling the determined at least one node comprises controlling the determined at least one node to output the LiFi signal using the infrared light source.

### Claim 14

The method of outputting LiFi signals by a node of a LiFi system, the method comprising:
outputting a LiFi signal at a first one or more frequencies via an infrared light source for reception by at least one endpoint device;
outputting at least one of a first indication via at least one of the infrared light source and a second indication via the visible light source, wherein the first indication and the second indication indicate that output of the LiFi signal will be transferred to the visible light source; and
wherein the node, in response to receiving input to provide illumination, when transmitting the LiFi signal via the infrared light source, turning on a visible light source to provide said illumination and automatically transferring an output of the LiFi signal from the infrared light source to the visible light source by:
outputting the LiFi signal at said first one or more frequencies via the visible light source for reception by said at least one endpoint device; and
turning off the infrared light source.

### Claim 15 (depends on 14)

The method according to claim 14, wherein the automatic transferring of said output of the LiFi signal comprises: outputting, via the infrared light source, an indication that output of the LiFi signal will be transferred to the visible light source.
