Method for wireless optical transmission of data and wireless optical data transmission system

• US 20060193634A1
• Filed: 01/26/2006
• Published: 08/31/2006
• Est. Priority Date: 02/28/2005
• Status: Active Grant

• Current Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Original Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Inventors: Wang, Zhaocheng, Uno, Masahiro, Huang, Kao-Cheng
• Granted Patent: US 7,546,038 B2
• Time in Patent Office: Days
• US Class Current: 398/118
• CPC Class Codes: H04B 10/1141 One-way transmission
• CPC Class Codes: H04B 10/116 Visible light communication

Abstract

The invention relates to a wireless optical data transmission system and a method for wireless optical transmission of data. The system comprises a data stream generator for generating at least two parallel data streams (18.1, 18.2, 18.3). The parallel data streams are transmitted by a number of separate optical transmitting devices (8, 9, 10) separately by emitting first optical signals. The system further comprises a corresponding number of detectors (19, 20, 21) for detecting the first optical signals and converting them into respective second signals (26.1, 26.2, 26.3) and an error correction unit (31) for correcting the amended second signals. Within a predistortion (29) unit each second signal (26.1, 26.2, 26.3) is amended individually with respect to a transmission channel used.

Claims

1. Method for wireless optical transmission of data comprising the steps of:

producing at least two parallel data streams (18.1, 18.2, 18.3)

wirelessly transmitting each data stream by a separate optical transmitting device (8, 9, 10), the transmitting devices emitting a first optical signal each

detecting the first optical signals by a corresponding number of separate detectors (19, 20, 21) and converting each first signal (18.1, 18.2, 18.3) into a respective second signal (26.1, 26.2, 26.3)

amending each second signal (26.1, 26.2, 26.3) individually by a predistortion unit (29) with respect to a transmission channel used and

performing an error correction on the amended second signals.

2. Method to claim 1,

characterised in that

the first optical signals (18.1, 18.2, 18.3) are emitted with a predefined power ratio (M_i).

3. Method according to claim 2,

characterised in that

three parallel data streams (18.1, 18.2, 18.3) are produced and transmitted by a green, a red and a blue LED (8, 9, 10) emitting a first optical signal each, the first optical signals having a predefined emitting optical power ratio (M_i) for emitting white light in sum.

4. Method according to claim 2 or 3,

characterised in that

the second signals (26.1, 26.2, 26.3) are amended with respect to the predefined power ratio (M_i) of the emitted signals.

5. Method according to any of the preceding claims,

characterised in that

the first optical signals are converted to second signals (26.1, 26.2, 26.3) with differing conversion efficiency (C_i).

6. Method according to claim 5,

characterised in that

the second signals (26.1, 26.2, 26.3) are amended with respect to the respective differing conversion efficiency (C_i).

7. Method to any of the preceding claims,

characterised in that

the separate detectors (19, 20, 21) produce parallel second signals (26.1, 26.2, 26.3) and the parallel second signals are converted to a common second signal r(t) comprising the second signals (26.1, 26.2, 26.3) before amending the second signals (26.1, 26.2, 26.3).

8. Method according to any of the preceding claims,

characterised in that

the second signals (26.1, 26.2, 26.3) are amended with respect to both the respective different predefined power ratio (M_i) of the emitted signals and the respective differing conversion efficiency (C_i).

9. Method according to any of the preceding claims,

characterised in that

the error correction is performed by a soft decision decoder (31).

16. A wireless data transmission system according to any of the preceding claims,

characterised in that

the system further comprises a parallel to serial converter (27) for converting the second signals (26.1, 26.2, 26.3) being produced in parallel by the detectors (19, 20, 21) into a common second signal (r(t), 28) comprising the second signals.

17. A wireless data transmission system according to any of the preceding claims,

characterised in that

the predistortion unit (19) is adopted to amend the second siganls (26.1, 26.2, 26.3) with respect to both the respective different predefined power ratio (M_i) of the emitted signals and the respective differing conversion efficiency (C_i).

18. A wireless data transmission system according to any of the preceding claims,

characterised in that

the system further comprises a soft decision decoder (31).

10. A wireless optical data transmission system comprising:

a data stream generator for generating at least two parallel data streams (18.1, 18.2, 18.3);

a number of separate optical transmitting devices (8, 9, 10) for wirelessly transmitting the parallel data streams (18.1, 18.2, 18.3) separately by emitting first optical signals;

a corresponding number of detectors (19, 20, 21) for detecting the first optical signals and converting them into respective second signals (26.1, 26.2, 26.3) and

an error correction unit (31) for correcting the amended second signals,

characterised in that

the system further comprises a predistortion (29) unit for amending each second signal (26.1, 26.2, 26.3) individually with respect to a transmission channel used.

11. A wireless data transmission system according to claim 10,

characterised in that

the separate optical transmitting devices (8, 9, 10) are adapted to emit the first optical signals with a predefined power ratio (M_i).

12. A wireless data transmission system according to claim 11,

characterised in that

the system comprises the optical transmitting devices (8, 9, 10) being a green LED, a red LED and a blue LED, the green, the red and the blue LED being adapted to emit light with a predefined optical power ratio (M_i) for emitting white light.

13. A wireless data transmission system according to claim 11 or 12,

characterised in that

the predistortion unit (19) is adapted to amend the second signals (26.1, 26.2, 26.3) with respect to the predefined power ratio (M_i).

14. A wireless data transmission system according to any of the claims 10 to 13,

characterised in that

the conversion efficiency (C_i) of the different detectors (19, 20, 21) is different.

15. A wireless data transmission system according to claim 14,

characterised in that

the predistortion unit (19) is adapted to amend the second signals (26.1, 26.2, 26.3) with respect to the respective differing conversion efficiency (C_i).