Method and system for identification of channels in an optical network

• US 20040062548A1
• Filed: 06/03/2003
• Published: 04/01/2004
• Est. Priority Date: 09/30/2002
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Alcatel-Lucent Canada Incorporated (Nokia Corporation)
• Inventors: Wan, Ping Wai, Remedios, Derrick, Kelly, Colin Geoffrey, Obeda, Paul David
• Granted Patent: US 7,142,783 B2
• Time in Patent Office: Days
• US Class Current: 398/25
• CPC Class Codes: H04B 10/00 Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
• CPC Class Codes: H04B 2210/071 using alarms
• CPC Class Codes: H04B 2210/074 using a superposed, over-modulated signal
• CPC Class Codes: H04B 2210/075 using a pilot tone
• CPC Class Codes: H04B 2210/077 using a separate fibre
• CPC Class Codes: H04B 2210/078 using a separate wavelength
• CPC Class Codes: H04J 14/0227 Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
• CPC Class Codes: H04J 14/0258 Wavelength identification or labelling
• CPC Class Codes: H04J 14/0267 Optical signaling or routing
• CPC Class Codes: H04J 14/0276 using pilot tones
• CPC Class Codes: H04J 14/0278 WDM optical network architectures
• CPC Class Codes: H04J 14/0298 with sub-carrier multiplexing [SCM]

Abstract

A method and system for identification of a channel in an optical network is provided. The channel is identified by the use of unique combinations of two or more low frequencies, or tones, modulated onto the channel and optionally, a network parameter associated with the channel.

Claims

1. A method for identifying an optical channel in an optical network, comprising the steps of:

marking the channel with a unique combination of two or more identification tags, the combination of identification tags being referred to as a channel signature, to identify the channel in the network; and

detecting the channel signature at various locations in the network.

2. A method as described in claim 1, wherein the step of marking comprises modulating the channel so that the identification tags are encoded onto the channel.

3. A method as described in claim 2, wherein the step of modulating comprises modulating the channel with the identification tags, which are low frequency dither tones.

4. A method as described in claim 3, wherein the step of modulating with the tones comprises one of the following types of modulation:

amplitude modulation, frequency modulation, phase modulation, and polarization modulation.

5. A method as described in claim 3, wherein the step of modulating comprises modulating the tones onto the channel in one of the following ways:

(a) modulated simultaneously;

(b) modulated consecutively; and

(c) modulated by using a combination of (a) and (b).

6. A method as described in claim 1, further comprising the step of verifying one or more restrictions imposed on the allocation of tones for the channel signature in the network, the step of verifying being performed before the step of marking.

7. A method as described in claim 6, wherein the step of verifying the restrictions comprises verifying that the tones in the channel signature are selected so that the frequency difference between any two tones in the channel signature is not less than a predetermined frequency spacing.

8. A method as described in claim 7, wherein the step of verifying that the tones in the channel signature are selected so that the frequency difference between any two tones in the channel signature is not less than a predetermined frequency spacing comprises selecting the predetermined frequency spacing from a range of frequency spacings from about 1 Hz to about 100 Hz.

9. A method as described in claim 7, wherein the step of verifying that the tones in the channel signature are selected so that the frequency difference between any two tones in the channel signature is not less than a predetermined frequency spacing comprises selecting the predetermined frequency spacing from a range of frequency spacings from about 8 Hz to about 10 Hz.

10. A method as described in claim 6, wherein the step of verifying the restrictions comprises verifying that channel signatures for different channels in the network are chosen so that, for channels destined to the same decoder in the network, a list of individual tones used in the channel signatures of said channels includes each tone only once.

11. A method as described in claim 6, further comprising the steps of:

maintaining a list of all tones to be used for channel signatures in the network;

releasing tones in unique combinations for use as channel signatures in the network; and

keeping track of tones available for further allocation to channel signatures in the network.

54. A method as described in claim 5, wherein the step of modulating the tones onto the channel consecutively comprises modulating the tones in a predetermined order so as to form a repeating consecutive sequence of tones, the repeating consecutive sequence of tones being the channel signature.

55. A method as described in claim 54, wherein the step of modulating the tones so as to form the repeating consecutive sequence of tones comprises modulating the tones so as to form the repeating consecutive sequence of tones, in which each tone is being used only once.

56. A method as described in claim 5, wherein the step of modulating the tones onto the channel consecutively comprises modulating two tones “

L”

times in total so as to form a repeating digital bit sequence pattern of length “

L”

, wherein one of the tones represents a logical “

0”

value, and the other tone respresents a logical “

1”

value, the repeating digital bit sequence pattern forming the channel signature or a part thereof.

57. A method as described in claim 5, wherein the step of modulating comprises modulating the channel with three tones.

58. A method as described in claim 5, wherein the step of modulating comprises modulating the channel with four tones forming two pairs of tones.

59. A method as described in claim 58, wherein the step of modulating the channel with four tones comprises selecting the four tones so that channel signatures for different channels in the network are chosen so that, for channels destined to the same decoder in the network, a list of individual tones used in the channel signatures of said channels includes each tone only once.

60. A method as described in claim 58, wherein the step of modulating comprises modulating the two pairs of tones onto the channel alternatively so that at any time only one of the two tone pairs is present.

61. A method as described in claim 58, wherein the step of modulating the tones onto the channel consecutively comprises modulating two tones pairs “

L”

times in total so as to form a repeating digital bit sequence pattern of tone pairs of length “

L”

, wherein one of the tone pairs represents a logical “

0”

value, and the other tone pair respresents a logical “

1”

value, the repeating digital bit sequence pattern of tone pairs forming the channel signature or a part thereof.

12. A system for identifying an optical channel in an optical network, comprising:

means for marking the channel with a unique combination of two or more identification tags, the combination of identification tags being referred to as a channel signature, to identify the channel in the network; and

means for detecting the channel signature at various locations in the network.

13. A system as described in claim 12, wherein the means for marking the channel with a unique combination of two or more identification tags comprises an encoder for encoding two or more frequency dither tones onto the optical channel, and the means for detecting comprises a decoder for decoding said low frequency dither tones from the optical channel.

14. A system as described in claim 13, wherein the encoder includes one of the following means for modulating the tones onto the channel:

(a) means for modulating the tones simultaneously;

(b) means for modulating the tones consecutively; and

(c) means comprising a combination of (a) and (b).

15. A system as described in claim 12, further comprising means for verifying one or more restrictions imposed on the allocation of tones for the channel signature in the network.

16. A system as described in claim 15, wherein the means for verifying comprises one or more of the following:

means for verifying that the tones in the channel signature are selected so that the frequency difference between any two tones in the channel signature is not less than a predetermined frequency spacing; and

means for verifying that channel signatures for different channels in the network are chosen so that, for channels destined to the same decoder in the network, a list of individual tones used in the channel signatures of said channels includes each tone only once.

17. A system as described in claim 15, further comprising:

means for maintaining a list of all tones to be used for channel signatures in the network;

means for releasing tones in unique combinations for use as channel signatures in the network; and

means for keeping track of tones available for further allocation to channel signatures in the network.

18. A method for identifying an optical channel in an optical network, comprising the steps of:

marking the channel with a unique combination of two or more identification tags, the combination of identification tags being referred to as a channel signature, to uniquely identify the channel in the network and one or more network parameters associated with the channel; and

detecting the channel signature at various locations in the network.

19. A method as described in claim 18, wherein the step of marking comprises modulating the channel with the identification tags, which are low frequency dither tones.

20. A method as described in claim 18, wherein the step of marking the channel comprises allocating one of the tones in the channel signature for identifying the channel, and allocating one or more of the remaining tones in the channel signature for identifying one or more parameters in the network associated with the channel.

21. A method as described in claim 20, wherein the step of marking the channel comprises allocating two or more tones in the channel signature for identifying the channel, and allocating one or more of the remaining tones in the channel signature for identifying one or more parameters in the network associated with the channel.

22. A method as described in claim 20, wherein the step of allocating the remaining tones comprises allocating the tones for identifying one or more of the following network parameters associated with the channel:

(a) an optical band including the channel;

(b) a source node in the network where the channel signature is marked;

(c) a destination node in the network where the channel signature is detected;

(d) an optical fiber carrying the channel; and

(e) an optical cable including the optical fiber carrying the channel.

23. A method as described in claim 21, wherein the step of allocating the remaining tones comprises allocating the tones for identifying one or more of the following network parameters associated with the channel:

(a) an optical band including the channel;

(b) a source node in the network where the channel signature is marked;

(c) a destination node in the network where the channel signature is detected;

(d) an optical fiber carrying the channel; and

(e) an optical cable including the optical fiber carrying the channel.

24. A method as described in claim 19, wherein the step of modulating with the tones comprises one of the following types of modulation:

amplitude modulation, frequency modulation, phase modulation, and polarization modulation.

25. A method as described in claim 19, wherein the step of modulating comprises modulating the tones onto the channel in one of the following ways:

(a) modulating simultaneously;

(b) modulating consecutively; and

(c) modulating by using a combination of (a) and (b).

26. A method as described in claim 18, further comprising the step of verifying one or more restrictions imposed on the allocation of tones for the channel signature in the network, the step of verifying being performed before the step of marking.

27. A method as described in claim 26, wherein the step of verifying the restrictions comprises verifying that the tones in the channel signature are selected so that the frequency difference between any two tones in the channel signature is not less than a predetermined frequency spacing.

28. A method as described in claim 27, wherein the step of verifying that the tones in the channel signature are selected so that the frequency difference between any two tones in the channel signature is not less than a predetermined frequency spacing comprises selecting the predetermined frequency spacing from a range of frequency spacings from about 1 Hz to about 100 Hz.

29. A method as described in claim 27, wherein the step of verifying that the tones in the channel signature are selected so that the frequency difference between any two tones in the channel signature is not less than a predetermined frequency spacing comprises selecting the predetermined frequency spacing from a range of frequency spacings from about 8 Hz to about 10 Hz.

30. A method as described in claim 26, wherein the step of verifying the restrictions comprises verifying that channel signatures for different channels in the network are chosen so that, for channels destined to the same decoder in the network, a list of individual tones used in the channel signatures of said channels includes each tone only once.

31. A method as described in claim 26, further comprising the steps of:

maintaining a list of all tones to be used for channel signatures in the network;

releasing tones in unique combinations for use as channel signatures in the network; and

keeping track of tones available for further allocation to channel signatures in the network.

32. A method as described in claim 20, wherein the step of marking comprises marking the channel with the channel signature comprising a pair of two dither tones.

33. A method as described in claim 32, wherein the step of marking the channel with the channel signature comprising the pair of two dither tones includes allocating one of the tones in the pair to identify the channel wavelength, and allocating the other tone in the pair to identify one of the following network parameters:

(a) an optical band including the channel;

(b) a source node in the network where the channel signature is marked;

(c) a destination node in the network where the channel signature is detected; and

(d) an optical fiber carrying the channel.

34. A method as described in claim 33, further comprising the step of selecting a plurality of unique pairs of tones, each tone in each pair being selected from a tonespace comprising a limited number of tones, and each pair of tones uniquely identifying the channel and the associated parameter in the network.

35. A method as described in claim 34, wherein the step of selecting comprises the steps of:

partitioning the tonespace into M blocks, each block comprising N tones; and

selecting the two tones in the pair from the same block, the tones in the block being used to uniquely identify one channel and the associated parameter in the network.

36. A method as described in claim 34, wherein the step of selecting comprises the steps of:

partitioning the tonespace into a first and second segments;

partitioning each segment into M blocks; and

selecting one tone in the pair from a block from the first segment, and the other tone in the pair from a block from the second segment.

37. A system for identifying an optical channel in an optical network, comprising:

means for marking the channel with a unique combination of two or more identification tags, the combination of identification tags being referred to as a channel signature, to uniquely identify the channel in the network and one or more network parameters associated with the channel; and

means for detecting the channel signature at various locations in the network.

38. A system as described in claim 37, wherein the means for marking comprises means for modulating the channel with the identification tags, which are low frequency dither tones.

39. A system as described in claim 37, wherein the means marking the channel comprises:

means for allocating one of the tones in the channel signature for identifying the channel; and

means for allocating one or more of the remaining tones in the channel signature for identifying one or more parameters in the network associated with the channel.

40. A system as described in claim 39, wherein the means for allocating comprises means for allocating the tones for identifying one or more of the following network parameters associated with the channel:

(a) an optical band including the channel;

(b) a source node in the network where the channel signature is marked;

(c) a destination node in the network where the channel signature is detected;

(d) an optical fiber carrying the channel; and

(e) an optical cable including the optical fiber carrying the channel.

41. A system as described in claim 38, wherein the means for modulating with the tones comprises means for modulating with one of the following types of modulation:

means for amplitude modulation, means for frequency modulation, means for phase modulation, and means for polarization modulation.

42. A system as described in claim 38, wherein the means for modulating comprises means for modulating the tones onto the channel in one of the following ways:

(a) means for modulating simultaneously;

(b) means for modulating consecutively; and

(c) means for modulating by using a combination of (a) and (b).

43. A system as described in claim 37, further comprising means for verifying one or more restrictions imposed on the allocation of tones for the channel signature in the network.

44. A system as described in claim 43, wherein the means for verifying the restrictions comprises means for verifying that the tones in the channel signature are selected so that the frequency difference between any two tones in the channel signature is not less than a predetermined frequency spacing.

45. A system as described in claim 44, wherein the means for verifying that the tones in the channel signature are selected so that the frequency difference between any two tones in the channel signature is not less than a predetermined frequency spacing comprises means for selecting the predetermined frequency spacing from a range of frequency spacings from about 1 Hz to about 100 Hz.

46. A system as described in claim 44, wherein the means for verifying that the tones in the channel signature are selected so that the frequency difference between any two tones in the channel signature is not less than a predetermined frequency spacing comprises means for selecting the predetermined frequency spacing from a range of frequency spacings from about 8 Hz to about 10 Hz.

47. A system as described in claim 43, wherein the means for verifying the restrictions comprises means for verifying that channel signatures for different channels in the network are chosen so that, for channels destined to the same decoder in the network, a list of individual tones used in the channel signatures of said channels includes each tone only once.

48. A system as described in claim 43, further comprising:

means for maintaining a list of all tones to be used for channel signatures in the network;

means for releasing tones in unique combinations for use as channel signatures in the network; and

means for keeping track of tones available for further allocation to channel signatures in the network.

49. A system as described in claim 39, wherein the means for marking comprises means for marking the channel with the channel signature comprising a pair of two dither tones.

50. A system as described in claim 49, wherein the means for marking comprises means for marking the channel with the channel signature comprising the pair of two dither tones includes means for allocating one of the tones in the pair to identify the channel wavelength, and means for allocating the other tone in the pair to identify one of the following network parameters:

(a) an optical band including the channel;

(b) a source node in the network where the channel signature is marked;

(c) a destination node in the network where the channel signature is detected; and

(d) an optical fiber carrying the channel.

51. A system as described in claim 50, further comprising the means for selecting a plurality of unique pairs of tones, each tone in each pair being selected from a tonespace comprising a limited number of tones, and each pair of tones uniquely identifying the channel and the associated parameter in the network.

52. A system as described in claim 51, wherein the means for selecting comprises:

means for partitioning the tonespace into M blocks, each block comprising N tones; and

means for selecting the two tones in the pair from the same block, the tones in the block being used to uniquely identify one channel and the associated parameter in the network.

53. A system as described in claim 51, wherein the means for selecting comprises:

means for partitioning the tonespace into a first and second segments;

means for partitioning each segment into M blocks; and

means for selecting one tone in the pair from a block from the first segment, and the other tone in the pair from a block from the second segment.