Illumination system for communicating data

Patent metadata

Field	Value
Publication number	US-10833765-B2
Application number	US-201816627436-A
Country	US
Kind code	B2
Filing date	Jul 10, 2018
Priority date	Jul 19, 2017
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

An uplink subsystem for use in an illumination system arranged for optical communication as well as the illumination system, the system comprising a downlink subsystem and the uplink subsystem. The uplink subsystem comprises sensors (e.g. infrared sensor) embedded in each luminaire in the group. The uplink subsystem also comprises a demodulator, and a distribution network for supplying the signals sensed to an adaptor to combine instances of the sensed uplink signal in a manner that takes into account a Time Division Medium Access scheme and a demodulator to demodulated the combined signal. The system further comprising a downlink subsystem that in turn comprises a modulator for generating a modulated waveform, and an optical fiber distribution network to distribute the modulated waveform to each luminaire in a group. Each such luminaire generates a drive current for driving a lighting element of that luminaire to emit light. Each also injects the modulated waveform into its drive current so as to embed the downlink signal in the emitted light.

First claim

The invention claimed is:

1. An uplink subsystem for use in an illumination system arranged for optical communication, the uplink subsystem comprising:
a group of luminaires;
a group of sensors each for sampling a respective instance of an uplink signal transmitted wirelessly from a user device, with a different respective one of the sensors being incorporated in or co-located with each of the luminaires of said group, or the sensors being interspersed amongst the luminaires so as to serve a same region of space as illuminated by the group of luminaires;
a demodulator unit; and
an uplink distribution network arranged to supply the respective instance of the uplink signal from each of group of the sensors to the demodulator unit;
wherein the demodulator unit comprises an adaptor arranged so as, based on a measurement of a respective received signal strength of each of the instances of the uplink signal, to apply a respective weight to each instance in dependence on the respective measurement of received signal strength, and to combine said instances of the uplink signal following the application of said weights, thereby producing a combined signal; and
the demodulator unit further comprises a demodulator arranged to demodulate the combined signal
and wherein
the uplink subsystem utilizes a Time Division Multiplex Access scheme in which time-slots are assigned to individual uplink users and wherein the adaptor assigns weights on a time-slot basis based on a respective uplink user assigned to a respective time-slot and previously recorded instances of the uplink signal where said user's uplink signal was detected, such that the switching of the weights for the instances of the uplink signal are synchronized with the time-slots and the weights are adapted for expected arrival of signals from the uplink user associated with the current time-slot.

2. The uplink subsystem of claim 1 , wherein the adaptor is implemented as one of:
a centralized adaptor, the centralized adaptor arranged to receive signals from the sensors of the group of sensors and combines instance of the uplink signal at the centralized adaptor,
a first distributed adaptor, the first distributed adaptor arranged to receive signals from the sensors of the group of sensors and combine instances of the uplink signal in a distributed manner and
a second distributed adaptor, the second distributed adaptor arranged to receive signals from the sensors of the group of sensors and combine instances of the uplink signal using a daisy chain approach.

3. The uplink subsystem of claim 1 , wherein the adaptor is configured to select said weights from a set comprising at least zero and one, and to select some of the weights to be zero if the respective measurement of received signal strength is below a threshold.

4. The uplink subsystem of claim 1 , wherein the measurement of received signal strength is a measure of signal strength relative to a noise floor; wherein either the noise floor is predetermined, or the adaptor is configured to determine the noise floor empirically based on a predetermined preamble in the uplink signal or a noise estimation algorithm which estimates the noise floor in presence during estimated periods of no uplink signal.

5. The uplink subsystem of claim 1 , wherein the uplink distribution network via which the instances of the uplink signal are supplied to demodulator unit is wholly or partially formed from optical fiber.

6. The uplink subsystem of claim 1 , wherein each of the luminaires is also arranged to emit a downlink signal by means of one of visible light communication of infrared light communication for detection by the user device.

7. The uplink subsystem of claim 1 , wherein each of said sensors comprises an infrared sensor, the uplink signal being received from the user device via infrared.

8. The uplink subsystem of claim 1 , wherein the uplink signal is modulated according to an OFDM scheme comprising different uplink subcarriers, and the demodulator unit comprises a phase shifter arranged to introduce a delay diversity between different ones of the uplink subcarriers.

9. An illumination system arranged for optical communication, the illumination system comprising an uplink subsystem according to claim 1 and a downlink subsystem,
the downlink subsystem comprising:
a group of luminaires;
a modulator unit for controlling the group of luminaires to emit a downlink signal for detection by a user device; and
a downlink distribution network connecting the modulator unit to each of the luminaires in said group;
wherein the modulator unit comprises a modulator configured to generate a modulated waveform corresponding to the downlink signal, and is arranged to transmit the modulated waveform to each of the luminaires in said group over the downlink distribution network;
each of the luminaires in said group comprises a lighting element for emitting light, and driver circuitry for driving the lighting element with a drive current powering the lighting element to emit said light; and
each of the luminaires in the group is arranged to receive the same modulated waveform from the modulator over the downlink distribution network, and further comprises a signal injector arranged to inject the modulated waveform into said drive current in order to cause the downlink signal to be embedded in the emitted light.

10. The system of claim 9 , wherein said lighting element is an illumination element for emitting visible illumination and infrared light, said light in which the downlink signal is embedded being the infrared illumination.

11. The system of claim 9 , wherein some or all of the downlink distribution network is formed from optical fiber routed through a same conduit or conduits as one or more power lines arranged to power one or more of the luminaires, the modulator unit and/or one or more other components.

12. The system of claim 9 , wherein the modulator is configured to generate said modulated waveform according to an OFDM scheme, such that the modulated waveform as transmitted over the downlink distribution network takes the form of an OFDM modulated waveform.

13. The system of claim 9 , wherein the downlink signal has a symbol wavelength in air when embedded in the light of greater than 3m.

14. The system of claim 9 , comprising a plurality of spatial regions optically separated from one another by opaque partitions, each of said regions comprising a respective set of data-emitting luminaires emitting light embedded with data, said group of luminaires being the set of data-emitting luminaires in one of said regions and said downlink signal communicating the respective data for that region;
wherein within each given one of said regions only the same data is embedded in any light emitted into that region, but the light emitted in different ones of said regions is embedded with different data.

15. The system of claim 9 , wherein the group of luminaires of the downlink subsystem being the group of luminaries of the uplink subsystem.

Assignees

• Signify Holding Bv

Inventors

• Linnartz Johan-Paul Marie Gerard
• Arulandu Kumar
• Courtois Fernand
• Chatel Xavier
• Jaudard Walter

Classifications

• H05B47/1985

  Creation of lighting zones or scenes · CPC title

• H05B47/195

  the transmission using visible or infrared light · CPC title

• H04B10/502

  LED transmitters · CPC title

• H04B10/116 Primary

  Visible light communication · CPC title

• H04B3/54

  Systems for transmission via power distribution lines · CPC title