TRANSMISSION OF IDENTIFIERS USING VISIBLE LIGHT COMMUNICATION

• US 20150372753A1
• Filed: 06/17/2015
• Published: 12/24/2015
• Est. Priority Date: 06/18/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Jovicic, Aleksandar, Pillai Perumal, Mahadevi
• Granted Patent: US 10,009,100 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 10/1141 One-way transmission
• CPC Class Codes: H04B 10/116 Visible light communication
• CPC Class Codes: H04L 7/041 using special codes as synchronising signal
• CPC Class Codes: H05B 45/12 using optical feedback

Abstract

Methods, systems, and devices are described for transmitting an identifier using visible light communication (VLC) and for generating a plurality of identifiers for transmission using VLC. Input identifying an illumination factor associated with a light source is received. A first set of modulation parameters is modified for transmitting the identifier using VLC. The first set of modulation parameters is modified based on the illumination factor. A signal, in which the identifier is encoded, is applied to the light source. The signal is applied according to the first set of modulation parameters. Another method includes identifying a number of light transmitting devices, generating a plurality of identifiers based on the identified number of light transmitting devices, storing the generated identifiers, determining a plurality of cyclic shifts for each identifier in the plurality of identifiers, and removing identifiers from the plurality of identifiers that match the identified cyclic shifts.

Claims

1. A method for transmitting an identifier using visible light communication (VLC), comprising:

receiving input identifying an illumination factor associated with a light source;

modifying a first set of one or more modulation parameters for transmitting the identifier using VLC, the first set of one or more modulation parameters being modified based at least in part on the illumination factor; and

applying at least one signal in which the identifier is encoded to the light source, the at least one signal being applied in accordance with the first set of one or more modulation parameters.

2. The method of claim 1, wherein the first set of one or more modulation parameters comprises at least one of a pulse duty cycle, a pulse duration, a pulse spacing, a DC bias, a pulse amplitude, or a pulse slope.

3. The method of claim 1, wherein the first set of one or more modulation parameters comprises a pulse slope, the pulse slope following one of a linear function, a piece-wise linear Gaussian function, a raised cosine function, a polynomial function, or an exponential function.

4. The method of claim 1, wherein application of the at least one signal to the light source modulates a light intensity of the light source to transmit the identifier from the light source using VLC.

5. The method of claim 1, wherein the at least one signal comprises at least one of a current signal or a voltage signal.

6. The method of claim 1, wherein the first set of one or more modulation parameters is further modified based at least in part on at least one member selected from a group consisting of:

a thermal performance of the light source, an acoustic performance of the light source, a flicker performance of the light source, and a signal-to-noise ratio (SNR) of a transmitted instance of the identifier.

7. The method of claim 1, wherein modifying the first set of one or more modulation parameters based at least in part on the illumination factor comprises:

converting the illumination factor to a total light output; and

modifying the first set of one or more modulation parameters based at least in part on the total light output.

8. The method of claim 7, wherein the illumination factor comprises a percentage of dimness and the total light output is expressed in lumens.

9. The method of claim 1, wherein modifying the first set of one or more modulation parameters comprises:

accessing an electronically stored database that associates illumination factors with modulation parameters.

10. The method of claim 9, wherein the electronically stored database associates at least one illumination factor with at least two different sets of one or more modulation parameters.

11. The method of claim 1, further comprising:

modifying a second set of one or more modulation parameters for transmitting an interleaving signal; and

alternately applying the at least one signal to the light source in accordance with the first set of one or more modulation parameters or the second set of one or more modulation parameters, to transmit a first plurality of instances of the identifier interspersed with a second plurality of instances of the interleaving signal.

12. The method of claim 11, wherein the second set of one or more modulation parameters is modified based at least in part on a thermal performance of the light source.

13. The method of claim 11, wherein the interleaving signal comprises a constant current or pulses having a fixed frequency.

14. The method of claim 11, wherein the second set of one or more modulation parameters differs from the first set of one or more modulation parameters.

15. The method of claim 11, wherein the second set of one or more modulation parameters is modified to match a first average light intensity level of a first transmitted instance of the interleaving signal to a second average light intensity level of a second transmitted instance of the identifier.

16. The method of claim 1, wherein the identifier is encoded in the at least one signal as a sequence of symbols.

17. The method of claim 16, wherein the sequence of symbols is based at least in part on a frequency shift keying.

18. A light transmitting device for transmitting an identifier using visible light communication (VLC), comprising:

means for receiving input identifying an illumination factor associated with a light source;

means for modifying a first set of one or more modulation parameters for transmitting the identifier using VLC, the first set of one or more modulation parameters being modified based at least in part on the illumination factor; and

means for applying at least one signal in which the identifier is encoded to the light source, the at least one signal being applied in accordance with the first set of one or more modulation parameters.

19. The light transmitting device of claim 18, wherein the first set of one or more modulation parameters comprises at least one of a pulse duty cycle, a pulse duration, a pulse spacing, a DC bias, a pulse amplitude, or a pulse slope.

20. The light transmitting device of claim 18, wherein the first set of one or more modulation parameters comprises a pulse slope, the pulse slope following one of a linear function, a piece-wise linear Gaussian function, a raised cosine function, a polynomial function, or an exponential function.

21. The light transmitting device of claim 18, wherein application of the at least one signal to the light source modulates a light intensity of the light source to transmit the identifier from the light source using VLC.

22. The light transmitting device of claim 18, wherein the at least one signal comprises at least one of a current signal or a voltage signal.

23. The light transmitting device of claim 18, wherein the first set of one or more modulation parameters is further modified based at least in part on at least one member selected from a group consisting of:

a thermal performance of the light source, an acoustic performance of the light source, a flicker performance of the light source, and a signal-to-noise ratio (SNR) of a transmitted instance of the identifier.

24. The light transmitting device of claim 18, wherein the means for modifying the first set of one or more modulation parameters based at least in part on the illumination factor comprises:

means for converting the illumination factor to a total light output; and

means for modifying the first set of one or more modulation parameters based at least in part on the total light output.

25. The light transmitting device of claim 18, wherein the means for modifying the first set of one or more modulation parameters comprises:

means for accessing an electronically stored database that associates illumination factors with modulation parameters.

26. The light transmitting device of claim 18, further comprising:

means for modifying a second set of one or more modulation parameters for transmitting an interleaving signal; and

means for alternately applying the at least one signal to the light source in accordance with the first set of one or more modulation parameters or the second set of one or more modulation parameters, to transmit a first plurality of instances of the identifier interspersed with a second plurality of instances of the interleaving signal.

27. The light transmitting device of claim 26, wherein the second set of one or more modulation parameters is modified based at least in part on a thermal performance of the light source.

28. The light transmitting device of claim 26, wherein the second set of one or more modulation parameters differs from the first set of one or more modulation parameters.

29. The light transmitting device of claim 26, wherein the second set of one or more modulation parameters is modified to match a first average light intensity level of a first transmitted instance of the interleaving signal to a second average light intensity level of a second transmitted instance of the identifier.

30. A light transmitting device for transmitting an identifier using visible light communication (VLC), comprising:

a processor;

memory in electronic communication with the processor; and

a receiver configured to receive input identifying an illumination factor associated with a light source; and

the processor further configured to;

modify a first set of one or more modulation parameters for transmitting the identifier using VLC, the first set of one or more modulation parameters being modified based at least in part on the illumination factor; and

apply at least one signal in which the identifier is encoded to the light source, the at least one signal being applied in accordance with the first set of one or more modulation parameters.

31. The light transmitting device of claim 30, wherein the first set of one or more modulation parameters comprises at least one of a pulse duty cycle, a pulse duration, a pulse spacing, a DC bias, a pulse amplitude, or a pulse slope.

32. The light transmitting device of claim 30, wherein application of the at least one signal to the light source modulates a light intensity of the light source to transmit the identifier from the light source using VLC.

33. The light transmitting device of claim 30, wherein the at least one signal comprises at least one of a current signal or a voltage signal.

34. The light transmitting device of claim 30, wherein the first set of one or more modulation parameters is further modified based at least in part on at least one member selected from a group consisting of:

a thermal performance of the light source, a flicker performance of the light source, and a signal-to-noise ratio (SNR) of a transmitted instance of the identifier.

35. The light transmitting device of claim 30, wherein the processor configured to modify the first set of one or more modulation parameters based at least in part on the illumination factor comprises a processor configured to:

convert the illumination factor to a total light output; and

modify the first set of one or more modulation parameters based at least in part on the total light output.

36. The light transmitting device of claim 30, wherein the processor configured to modify the first set of one or more modulation parameters comprises a processor configured to:

access an electronically stored database that associates illumination factors with modulation parameters.

37. The light transmitting device of claim 30, wherein the processor is further configured to:

modify a second set of one or more modulation parameters for transmitting an interleaving signal; and

alternately apply the at least one signal to the light source in accordance with the first set of one or more modulation parameters or the second set of one or more modulation parameters, to transmit a first plurality of instances of the identifier interspersed with a second plurality of instances of the interleaving signal.

38. The light transmitting device of claim 37, wherein the second set of one or more modulation parameters is modified based at least in part on a thermal performance of the light source.

39. The light transmitting device of claim 37, wherein the second set of one or more modulation parameters is modified to match a first average light intensity level of a first transmitted instance of the interleaving signal to a second average light intensity level of a second transmitted instance of the identifier.

40. The light transmitting device of claim 30, wherein the identifier is encoded in the at least one signal as a sequence of symbols.

41. A non-transitory computer-readable medium storing instructions executable by a processor to cause a device to:

receive input identifying an illumination factor associated with a light source;

modify a first set of one or more modulation parameters for transmitting an identifier using VLC, the first set of one or more modulation parameters being modified based at least in part on the illumination factor; and

apply at least one signal in which the identifier is encoded to the light source, the at least one signal being applied in accordance with the first set of one or more modulation parameters.

42. A method for generating a plurality of identifiers for transmission using visible light communication (VLC), comprising:

identifying a number of light transmitting devices;

generating the plurality of identifiers based at least in part on the number of light transmitting devices;

storing the plurality of identifiers;

determining a plurality of cyclic shifts for each identifier of the plurality of identifiers;

removing identifiers from the plurality of identifiers that match the plurality of cyclic shifts; and

assigning each of the number of light transmitting devices a unique identifier from among the identifiers that remain in the plurality of identifiers after removing the identifiers that match the plurality of cyclic shifts.

43. The method of claim 42, wherein generating the plurality of identifiers comprises:

selecting an identifier length and an alphabet for generating the plurality of identifiers.

44. The method of claim 43, wherein generating the plurality of identifiers comprises:

selecting the identifier length and the alphabet based at least in part on a number of alphabet characters and the number of light transmitting devices; and

generating the plurality of identifiers as different combinations of the number of alphabet characters having the identifier length.

45. The method of claim 42, wherein assigning the each of the number of light transmitting devices a unique identifier comprises:

transmitting the unique identifier to a light transmitting device.

46. The method of claim 42, wherein assigning the each of the number of light transmitting devices a unique identifier comprises:

transmitting an index to a light transmitting device, the index indicating which of the plurality of identifiers stored at the light transmitting device is to be used as the unique identifier of the light transmitting device.

47. A controller for generating a plurality of identifiers for transmission using visible light communication (VLC), comprising:

means for identifying a number of light transmitting devices;

means for generating the plurality of identifiers based at least in part on the number of light transmitting devices;

means for storing the plurality of identifiers;

means for determining a plurality of cyclic shifts for each identifier of the plurality of identifiers;

means for removing identifiers from the plurality of identifiers that match the plurality of cyclic shifts; and

means for assigning each of the number of light transmitting devices a unique identifier from among the identifiers that remain in the plurality of identifiers after removing the identifiers that match the plurality of cyclic shifts.

48. The controller of claim 47, wherein the means for generating the plurality of identifiers comprises:

means for selecting an identifier length and an alphabet for generating the plurality of identifiers.

49. The controller of claim 48, wherein the means for generating the plurality of identifiers comprises:

means for selecting the identifier length and the alphabet based at least in part on a number of alphabet characters and the number of light transmitting devices; and

means for generating the plurality of identifiers as different combinations of the number of alphabet characters having the identifier length.

50. The controller of claim 47, wherein the means for assigning each of the number of light transmitting devices a unique identifier comprises:

means for transmitting the unique identifier to a light transmitting device.

51. The controller of claim 47, wherein the means for assigning each of the number of light transmitting devices a unique identifier comprises:

means for transmitting an index to a light transmitting device, the index indicating which of the plurality of identifiers stored at the light transmitting device is to be used as the unique identifier of the light transmitting device.

52. A controller for generating a plurality of identifiers for transmission using visible light communication (VLC), comprising:

a processor configured to;

identify a number of light transmitting devices; and

generate the plurality of identifiers based at least in part on the number of light transmitting devices;

memory configured to store the plurality of identifiers;

wherein the processor is further configured to;

determine a plurality of cyclic shifts for each identifier of the plurality of identifiers;

remove identifiers from the plurality of identifiers that match the plurality of cyclic shifts; and

assign each of the number of light transmitting devices a unique identifier from among the identifiers that remain in the plurality of identifiers after removing the identifiers that match the plurality of cyclic shifts; and

a transmitter configured to transmit an index to of a light transmitting device, the index indicating which of the plurality of identifiers stored at the light transmitting device is to be used as the unique identifier of the at least one of the light transmitting device.

53. The controller of claim 52, wherein the processor configured to generate the plurality of identifiers comprises a processor configured to:

select an identifier length and an alphabet for generating the plurality of identifiers.

54. The controller of claim 53, wherein the processor configured to generate the plurality of identifiers comprises a processor configured to:

select the identifier length and the alphabet based at least in part on a number of alphabet characters and the number of light transmitting devices; and

generate the plurality of identifiers as different combinations of the number of alphabet characters having the identifier length.

55. A non-transitory computer-readable medium storing instructions executable by a processor to cause a device to:

identify a number of light transmitting devices;

generate a plurality of identifiers based at least in part on the number of light transmitting devices;

store the plurality of identifiers;

determine a plurality of cyclic shifts for each identifier of the plurality of identifiers;

remove identifiers from the plurality of identifiers that match the plurality of cyclic shifts; and

assign each of the number of light transmitting devices a unique identifier from among the identifiers that remain in the plurality of identifiers after removing the identifiers that match the plurality of cyclic shifts.

56. A method for wireless communication, comprising:

transmitting input identifying an illumination factor associated with a light source to a light transmitting device via a controller;

receiving at least one signal using visible light communication (VLC), the at least one signal comprising an identifier of the light transmitting device, wherein the at least one signal is generated at the light transmitting device in accordance with a first set of one or more modulation parameters, the first set of one or more modulation parameters being modified based at least in part on the illumination factor; and

decoding the at least one signal to obtain the identifier.

57. The method of claim 56, wherein the first set of one or more modulation parameters comprises a pulse slope, the pulse slope following one of a linear function, a piece-wise linear Gaussian function, a raised cosine function, a polynomial function, or an exponential function.

58. The method of claim 56, wherein the at least one signal being generated at the light transmitting device comprises a light intensity of the light source being modulated in accordance with the first set of one or more modulation parameters to transmit the identifier from the light transmitting device using VLC.

59. The method of claim 56, wherein the first set of one or more modulation parameters being modified based at least in part on the illumination factor comprises the illumination factor being converted to a total light output;

and the first set of one or more modulation parameters being modified based at least in part on the total light output.

60. The method of claim 59, wherein the illumination factor comprises a percentage of dimness and the total light output is expressed in lumens.

61. The method of claim 56, further comprising:

receiving an interleaving signal, wherein a first plurality of instances of the identifier is interspersed with a second plurality of instances of the interleaving signal, and wherein the at least one signal is alternately generated at the light transmitting device in accordance with the first set of one or more modulation parameters or a second set of one or more modulation parameters.

62. The method of claim 61, wherein the second set of one or more modulation parameters is modified based at least in part on a thermal performance of the light source.

63. The method of claim 61, wherein the second set of one or more modulation parameters differs from the first set of one or more modulation parameters.

64. The method of claim 61, wherein the second set of one or more modulation parameters is modified to match a first average light intensity level of a first transmitted instance of the interleaving signal to a second average light intensity level of a second transmitted instance of the identifier.

65. A mobile device for wireless communication, comprising:

means for transmitting input identifying an illumination factor associated with a light source to a light transmitting device via a controller;

means for receiving at least one signal using visible light communication (VLC), the at least one signal comprising an identifier of the light transmitting device, wherein the at least one signal is generated at the light transmitting device in accordance with a first set of one or more modulation parameters, the first set of one or more modulation parameters being modified based at least in part on the illumination factor; and

means for decoding the at least one signal to obtain the identifier.

66. A mobile device for wireless communication, comprising:

a processor;

memory in electronic communication with the processor;

a transceiver configured to transmit input identifying an illumination factor associated with a light source to a light transmitting device via a controller; and

an image sensor configured to receive at least one signal using visible light communication (VLC), the at least one signal comprising an identifier of the light transmitting device, wherein the at least one signal is generated at the light transmitting device in accordance with a first set of one or more modulation parameters, the first set of one or more modulation parameters being modified based at least in part on the illumination factor; and

the processor further configured to decode the at least one signal to obtain the identifier.

67. The mobile device of claim 66, wherein the first set of one or more modulation parameters comprises at least one of a pulse duty cycle, a pulse duration, a pulse spacing, a DC bias, a pulse amplitude, or a pulse slope.

68. The mobile device of claim 66, wherein the at least one signal being generated at the light transmitting device comprises a light intensity of the light source being modulated in accordance with the first set of one or more modulation parameters to transmit the identifier from the light transmitting device using VLC.

69. The mobile device of claim 66, wherein the first set of one or more modulation parameters being modified based at least in part on the illumination factor comprises the illumination factor being converted to a total light output;

and the first set of one or more modulation parameters being modified based at least in part on the total light output.

70. The mobile device of claim 69, wherein the illumination factor comprises a percentage of dimness and the total light output is expressed in lumens.

71. The mobile device of claim 66, wherein the transceiver is further configured to:

receive an interleaving signal, wherein a first plurality of instances of the identifier is interspersed with a second plurality of instances of the interleaving signal, and wherein the at least one signal is alternately generated at the light transmitting device in accordance with the first set of one or more modulation parameters or a second set of one or more modulation parameters.

72. The mobile device of claim 71, wherein the second set of one or more modulation parameters is modified based at least in part on a thermal performance of the light source.

73. The mobile device of claim 71, wherein the second set of one or more modulation parameters differs from the first set of one or more modulation parameters.

74. The mobile device of claim 71, wherein the second set of one or more modulation parameters is modified to match a first average light intensity level of a first transmitted instance of the interleaving signal to a second average light intensity level of a second transmitted instance of the identifier.