Light communication system, transmitter and receiver

Patent metadata

Field	Value
Publication number	US-9312954-B2
Application number	US-201213712748-A
Country	US
Kind code	B2
Filing date	Dec 12, 2012
Priority date	Aug 28, 2012
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

A light communication system, a transmitter and a receiver are provided. The light communication system includes the transmitter and the receiver. The transmitter has a first processing unit and a light-emitting element. The first processing unit produces a transmission signal. The light-emitting element produces light to carry the transmission signal. The receiver has a first variable lens, a photosensitive element and a second processing unit. The first variable lens changes the propagation path of the light. The photosensitive element senses the light passed through the first variable lens to produce a receiving signal. The second processing unit controls the first variable lens based on the signal quality of the receiving signal to change the equivalent channel between the transmission signal and the receiving signal. Therefore, the transmission capability of the light communication system is enhanced.

First claim

What is claimed is:

1. A light communication system, comprising:
a transmitter including a first processing unit that generates a transmission signal, and at least two light-emitting diodes arranged in a first column that emit light that carries the transmission signal; and
a receiver including at least two first variable lenses arranged in a second column that correspond to the at least two light-emitting diodes in the first column to receive the light emitted by the at least two light-emitting diodes and change a propagation path of the light, at least two photosensitive elements arranged in a third column that correspond to the at least two first variable lenses in the second column to sense the light passing through the at least two first variable lenses to produce receiving signals, and a second processing unit that respectively controls the at least two first variable lenses according to signal qualities of the receiving signals of the at least two photosensitive elements in order to change equivalent channels between the transmission signal of the first processing unit and the receiving signals of the at least two photosensitive elements.

2. The light communication system of claim 1 , wherein the second processing unit produces a first control signal based on the signal qualities of the receiving signals and uses the first control signal to control curvatures, angles, thicknesses, focal lengths, axial directions or refractive indexes of the at least two first variable lenses or spacing between the at least two first variable lenses and the at least two photosensitive elements accordingly in order to change the propagation paths of the light and in turn the equivalent channels.

3. The light communication system of claim 1 , wherein the transmitter further includes a second variable lens, and the first processing unit produces a second control signal based on a feedback signal of the second processing unit, and uses the second control signal to control a curvature, an angle, a thickness, a focal length, an axial direction or a refractive index of the second variable lens or a spacing between the second variable lens and the light-emitting diode accordingly in order to change the propagation paths of the light and in turn the equivalent channels.

4. The light communication system of claim 3 , wherein the first variable lens or the second variable lens is one selected from the group consisting of a liquid lens, a MEMS-based variable micro-lens, and a piezoelectric material (Pb(ZrTi)O 3 or PZT)-based variable lens.

5. The light communication system of claim 3 , wherein the signal quality includes Received Signal Strength Indication (RSSI), Signal-to-Interference-plus-Noise Ratio (SINR), Bit Error Rate (BER), Frame Error Rate (FER) or matrix rank, and the feedback signal includes signal quality information, direction information, channel information, precoding information or information on matrix rank.

6. The light communication system of claim 1 being a Multi Input Multi Output (MIMO) system.

7. A transmitter, which proceeds light communication with an external receiver, the transmitter comprising:
a processing unit that generates transmission signals;
at least two light-emitting diodes arranged in a first column that emit light that carries the transmission signals; and
at least two variable lenses arranged in a second column that correspond to the at least two light-emitting diodes in the first column to receive the light emitted by the at least two light-emitting diodes, and change a propagation path of the light, wherein at least two photosensitive elements of the receiver arranged in a third column correspond to the at least two variable lenses in the second column to receive the light passing through the at least two variable lenses so as to produce receiving signals, the processing unit produces control signals based on a feedback signal produced by the receiver, and uses the control signals produced based on the feedback signal to control the at least two variable lenses accordingly, which change the propagation paths of the light and equivalent channels between the transmission signals of the processing unit and the receiving signals of the receiver.

8. The transmitter of claim 7 , wherein the processing unit uses the control signals to control curvatures, angles, thicknesses, focal lengths, axial directions or refractive indexes of the at least two variable lenses or spacing between the at least two variable lenses and the light-emitting diode accordingly in order to change the propagation paths of the light and in turn the equivalent channels.

9. A receiver, which proceeds light communication with an external transmitter, the receiver comprising:
at least two variable lenses that have adjustable curvatures, thicknesses or refractive indexes, wherein at least two light-emitting diodes of the transmitter are arranged in a first column, the at least two variable lenses are arranged in a second column correspond to the at least two light-emitting diodes in the first column and change propagation paths of light emitted by the at least two light-emitting diodes, the light carries a transmission signal produced by the at least two light-emitting diodes;
at least two photosensitive elements arranged in a third column that correspond to the at least two variable lenses in the second column to sense the light passing through the at least two variable lenses and generate receiving signals; and
a processing unit that generates control signals based on signal qualities of the receiving signals and uses the control signals to control the curvatures, thicknesses or refractive indexes of the at least two variable lenses accordingly, which changes the propagation paths of the light and equivalent channels between the transmission signals of the transmitter and the receiving signal of the at least two photosensitive elements.

10. The receiver of claim 9 , wherein the processing unit further uses the control signals to control angles, focal lengths or axial directions of the at least two variable lenses or spacing between the at least two variable lenses and the at least two photosensitive elements accordingly in order to change the propagation paths of the light and in turn the equivalent channels.

Assignees

• Ind Tech Res Inst

Inventors

• Chen Ren-Jr
• Hsiao Chang-Lung
• Lin Chun-Chuan
• Tai Tsai-Lin
• Chung Lung-Pin
• Chen Hsiu-Hsiang

Classifications

• H04B10/11 Primary

  Arrangements specific to free-space transmission, i.e. transmission through air or vacuum · CPC title

• H04B10/1143 Primary

  Bidirectional transmission · CPC title