Method and device for optical transmission at adaptive effective rates

Patent metadata

Field	Value
Publication number	US-9967047-B2
Application number	US-201414297469-A
Country	US
Kind code	B2
Filing date	Jun 5, 2014
Priority date	Jun 7, 2013
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A method for transmitting digital data by a primary optical signal between a transmitter terminal and a receiver terminal, involves the following steps: determining a magnitude characterizing optical-wave degradation between the transmitter terminal and the receiver terminal, determining a number of transmission channels by a decreasing function of the magnitude characterizing optical-wave degradation, distributing the digital data over the transmission channels, modulating optical signals of different wavelengths using digital data distributed over the transmission channels, generating the primary optical signal by wavelength multiplexing of the optical signals, and sending a transmission configuration, including at least the number of transmission channels, from the transmitter terminal to the receiver terminal.

First claim

The invention claimed is:

1. A method for transmitting digital data through space and/or the atmosphere by a primary optical signal between a transmitter terminal and a receiver terminal, comprising the following steps:
determining a magnitude characterizing optical-wave degradation between the transmitter terminal and the receiver terminal,
determining a number of transmission channels by a first stepwise decreasing function of the magnitude characterizing optical-wave degradation,
distributing the digital data over the transmission channels,
modulating optical signals of different wavelengths, of which there are as many as there are transmission channels; each of the respective optical signals being modulated by digital data distributed respectively to one of the transmission channels,
generating the primary optical signal by wavelength multiplexing of the optical signals, and
sending a transmission configuration through space and/or the atmosphere from the transmitter terminal to the receiver terminal; the transmission configuration including at least the number of transmission channels.

2. The method as claimed in claim 1 , further comprising:
determining an encoding rate, using a second decreasing function of the magnitude characterizing optical-wave degradation,
encoding the digital data distributed to each of the transmission channels according to the previously determined encoding rate;
the encoding rate being defined as a ratio between an effective bit rate and an output bit rate transmitted from an encoder; the transmission configuration also including the encoding rate.

3. The method as claimed in claim 1 , further comprising an interlacing step for the digital data distributed to each of the transmission channels; the transmission configuration also including information relating to an interlacing configuration.

4. The method as claimed in claim 1 , wherein the magnitude characterizing optical-wave degradation is determined by measuring, at the transmitter terminal, a secondary optical signal sent by the receiver terminal and received by the transmitter terminal; and wherein the magnitude characterizing optical-wave degradation comprises a magnitude characterizing optical-wave degradation through space and/or the atmosphere.

5. The method as claimed in claim 1 , wherein the magnitude characterizing optical-wave degradation is determined by calculation using a predetermined function.

6. The method as claimed in claim 1 , further comprising a time-division multiplexing step for the transmission configuration and effective data distributed to at least one of the transmission channels.

7. The method as claimed in claim 1 , further comprising an analogue overmodulation step for one of the optical signals using the transmission configuration.

8. The method as claimed in claim 1 , further comprising a reconstitution step for the digital data received by the receiver terminal configured in real time using the transmission configuration.

9. A device for transmitting digital data through space and/or the atmosphere using a primary optical signal including a transmitter terminal and a receiver terminal; said transmitter terminal comprising:
a processor configured to distribute and send digital data over transmission channels,
optical sources configured to send optical signals of different wavelengths through space and/or the atmosphere; each of the optical sources having a modulator to modulate the optical signal of said optical source as a function of digital data sent by the processor over a transmission channel, and
a wavelength multiplexer configured to generate the primary optical signal by wavelength multiplexing of optical signals sent by the optical sources;

and further comprising:
the processor configured to determine a magnitude characterizing an optical-wave degradation between the transmitter terminal and the receiver terminal,
the processor configured to distribute the digital data over a number of transmission channels that is less than or equal to the number of optical sources,
the processor configured to determine the number of transmission channels with a stepwise decreasing function of the magnitude characterizing optical-wave degradation, and
a number of optical sources equal to the number of transmission channels and the optical sources being configured to be activated; the primary optical signal being generated by multiplexing the optical signals sent by the optical sources thus activated; each of the optical signals being modulated by digital data.

10. The device as claimed in claim 9 , in which the processor of the transmitter terminal is further configured to encode digital data distributed to each of the transmission channels,
said encoding being characterized by a variable encoding rate determined by the processor configured to implement a decreasing function of the magnitude characterizing optical-wave degradation, and
said encoding rate being defined as a ratio between an effective bit rate and a bit rate outputted from an encoder.

11. The device as claimed in claim 9 , in which the processor of the transmitter terminal is further configured to interlace digital data distributed to each of the transmission channels.

12. The device as claimed in claim 9 , wherein the receiver terminal includes an optical source and an optical transmission interface that are configured to transmit a secondary optical signal to the transmitter terminal, and an optical receiver interface of the secondary optical signal that is configured to receive the secondary optical signal; the magnitude characterizing optical-wave degradation between the transmitter terminal and the receiver terminal being measured by receipt of the optical signal; and wherein the magnitude characterizing optical-wave degradation comprises a magnitude characterizing optical-wave degradation through space and/or the atmosphere.

13. The device as claimed in claim 9 , wherein the transmitter terminal includes an optical power amplifier to amplify the primary optical signal.

14. The device as claimed claim 9 , wherein the transmitter terminal includes a device configured to transmit a tertiary signal to the receiver terminal, and in which the receiver terminal includes a device configured to receive the tertiary signal; and the tertiary signal carrying a transmission configuration including at least the number of transmission terminals, enabling the receiver terminal to process the effective data sent by the primary optical signal.

15. The device as claimed in claim 14 , wherein the tertiary signal is an optical signal with a wavelength different from the wavelengths of the optical signals carrying the effective data.

16. The device as claimed in claim 14 , wherein the tertiary signal is a hyperfrequency signal.

17. The device as claimed in claim 9 , wherein the receiver terminal includes:
a wavelength demultiplexer that is configured to generate optical signals of different wavelengths by demultiplexing the primary optical signal,
converters that are configured to convert each of the optical signals of different wavelengths into electrical signals, and
a processor configured to recombine electrical signals to reconstitute the digital data sent by the transmitter terminal.

18. A method for transmitting digital data through free space by a primary optical signal between a transmitter terminal and a receiver terminal, comprising the following steps:
determining a magnitude characterizing optical-wave degradation between the transmitter terminal and the rece

Assignees

• Thales Sa

Inventors

• Le Kernec Arnaud
• Dervin Mathieu
• Sotom Michel

Classifications

• H04B10/112 Primary

  Line-of-sight transmission over an extended range · CPC title

• H04B10/29

  Repeaters · CPC title

• H04B10/25752

  Optical arrangements for wireless networks · CPC title

• H04J14/02 Primary

  Wavelength-division multiplex systems · CPC title

• H04B10/118 Primary

  specially adapted for satellite communication · CPC title