SYNCHRONIZATION OF COMMUNICATION EQUIPMENT

• US 20110110359A1
• Filed: 07/13/2009
• Published: 05/12/2011
• Est. Priority Date: 07/11/2008
• Status: Active Grant

• Current Assignee: Genesis Technical Systems Corp.
• Original Assignee: Genesis Technical Systems Corp.
• Inventors: Zottola, Tino, Cooke, Stephen P.
• Granted Patent: US 8,711,836 B2
• Time in Patent Office: Days
• US Class Current: 370/350
• CPC Class Codes: H04J 3/0617 the synchronising signal being characterised by the frequency or phase
• CPC Class Codes: H04J 3/0638 Clock or time synchronisation among nodes; Internode synchronisation synchronization for ring networks H04L12/422; data switching networks with synchronous transmission H04L12/43
• CPC Class Codes: H04J 3/0688 Change of the master or reference, e.g. take-over or failure of the master
• CPC Class Codes: H04L 1/242 by comparing a transmitted test signal with a locally generated replica
• CPC Class Codes: H04L 12/2865 Logical combinations
• CPC Class Codes: H04L 12/42 Loop networks
• CPC Class Codes: H04L 7/0008 Synchronisation information channels, e.g. clock distribution lines
• CPC Class Codes: H04M 11/062 using different frequency bands for speech and other data
• CPC Class Codes: H04Q 2213/13039 Asymmetrical two-way transmission, e.g. ADSL, HDSL
• CPC Class Codes: H04Q 2213/13098 Mobile subscriber
• CPC Class Codes: H04Q 2213/13106 Microprocessor, CPU
• CPC Class Codes: H04Q 2213/1319 Amplifier, attenuation circuit, echo suppressor
• CPC Class Codes: H04Q 2213/13298 Local loop systems, access network
• CPC Class Codes: H04Q 2213/1336 Synchronisation
• CPC Class Codes: H04Q 2213/13389 LAN, internet

Abstract

Apparatus and methods relating to synchronization of communication equipment are disclosed. Synchronization information received from a bonded communication link can be used to synchronize local and/or remote communication equipment, such as femtocell sites coupled to nodes in a ring network. This may involve isolating a frequency reference signal from a DSL (Digital Subscriber Line) communication link which is a constituent link of a bonded communication link, for example. In a ring network, received synchronization information could be used in synchronizing a locally connected installation of communication equipment, and passed for transmission in the ring network for synchronizing other communication equipment. Such dropping and passing of an analog frequency reference signal could be applied in networks having other topologies as well. At least some embodiments of the invention are applicable to optical links. One or more dedicated wavelengths of an optical link could be used to transfer a frequency reference signal, for example. Other functions, such as quality monitoring, quality reporting, and/or predictive traffic forwarding may be provided in some embodiments.

Claims

1. An apparatus comprising:

a synchronization information receiver to receive network synchronization information from a network communication link that enables communications with a communication network, the received network synchronization information for synchronizing communication equipment with the communication network; and

a synchronization information distributor to provide, based on the received network synchronization information, local synchronization information for synchronizing the communication equipment with the communication network.

2. The apparatus of claim 1, wherein the synchronization information distributor is further operable to provide, based on the received network synchronization information, remote synchronization information for transmission to further communication equipment, the remote synchronization information for synchronizing the further communication equipment with the communication network.

3. The apparatus of claim 1, wherein the communication equipment and the remote communication equipment comprise respective installations of wireless communication equipment that provide a wireless communication service within respective service areas, the installations of wireless communication equipment being associated with one or more wireless service providers.

4. The apparatus of claim 2,

wherein the received network synchronization information comprises a synchronization packet,

wherein the synchronization packet has a first priority, and

wherein the synchronization information distributor is operable to provide the remote synchronization information by changing the priority of the synchronization packet to a second priority.

5. The apparatus of claim 2,

wherein the received network synchronization information comprises a synchronization packet,

wherein the synchronization information distributor is operable to provide the synchronization packet as the local synchronization information, and

wherein the synchronization information distributor comprises a synchronization information generator to generate as the remote synchronization information a frequency reference standard based on the received synchronization packet.

6. The apparatus of claim 2,

wherein the received network synchronization information comprises a frequency reference signal,

wherein the synchronization information distributor is operable to provide the frequency reference signal as the local synchronization information, and

wherein the synchronization information distributor comprises a synchronization information generator to generate as the remote synchronization information a synchronization packet based on the received frequency reference signal.

7. The apparatus of claim 1, further comprising:

a quality monitor to monitor a quality measure of the received network synchronization information.

8. The apparatus of claim 7, wherein the quality monitor is further operable to report a monitoring result via the network communication link.

9. The apparatus of claim 2, further comprising:

a quality monitor to monitor a quality measure of the received network synchronization information, and to perform at least one of;

receiving quality monitoring information associated with the remote synchronization information and reporting a monitoring result to the further communication equipment.

10. The apparatus of claim 9, wherein the quality monitor is further operable to detect a quality problem with the remote synchronization information based on the received quality monitoring information, and to perform, responsive to detecting the quality problem, at least one of:

causing a characteristic of the remote synchronization information to be adjusted and reporting the quality problem via the network communication link.

11. The apparatus of claim 7, wherein the received network synchronization information comprises multiple sets of redundant synchronization information, and wherein one of the multiple sets of redundant synchronization information is selected for use as basis for the local synchronization information responsive to a result of monitoring by the quality monitor.

12. The apparatus of claim 2, wherein the synchronization information distributor is operable to provide the remote synchronization information for transmission to the further communication equipment through at least one of:

a ring communication network, a bonded communication link, an optical communication link, and a wireless communication link.

13. The apparatus of claim 2, wherein the synchronization information distributor is further operable to transmit the remote synchronization information using one or more of:

RPR (Resilient Packet Ring), Ethernet, and VDSL2 (Very high bit rate Digital Subscriber Line version

     2).

14. The apparatus of claim 1, wherein the network communication link comprises a bonded DSL (Digital Subscriber Line) link.

15. The apparatus of claim 2, wherein the synchronization information distributor is operable to provide the local synchronization information and the remote synchronization information based on the received network synchronization information where no new network synchronization information is received during a holdover time period.

16. The apparatus of claim 1, wherein the network communication link comprises a bonded communication link, and wherein the synchronization information receiver isolates a frequency reference signal from a DSL (Digital Subscriber Line) communication link which is a constituent link of the bonded communication link, the received frequency reference signal comprising the network synchronization information.

17. The apparatus of claim 16, further comprising:

a quality monitor to monitor a quality measure of the received network synchronization information, and to use the frequency reference signal as a messaging channel to report a monitoring result.

18. The apparatus of claim 16, further comprising:

a quality monitor to monitor a quality measure of the received network synchronization information,

wherein the synchronization information receiver is further operable to isolate respective frequency reference signals from multiple DSL communication links of the bonded communication link, and wherein one of the redundant frequency reference signals is selected for use as basis for the local synchronization information responsive to a result of monitoring by the quality monitor.

19. The apparatus of claim 18, wherein the quality measure comprises respective error rates of the redundant frequency reference signals, wherein the redundant frequency reference signal having a lowest error rate is selected for use as basis for the local synchronization information, and wherein the synchronization information distributor is operable to determine the respective error rates based on a PRBS (Pseudo-Random Bit Sequence) that is combined with the redundant frequency reference signals.

20. The apparatus of claim 16, wherein the received frequency reference signal comprises DSL traffic being transferred on the DSL communication link, and wherein the local synchronization information comprises a clock signal recovered from the DSL traffic.

21. The apparatus of claim 1,

wherein the network synchronization information comprises network synchronization information being transferred in a ring communication network that is operatively coupled to the communication network, the received network synchronization information for synchronizing, with the communication network, installations of communication equipment that are operatively coupled to the ring communication network,

wherein the communication equipment comprises one of the installations of communication equipment operatively coupled to the ring communication network, and

wherein the synchronization information distributor is further operable to provide the received synchronization information for transmission in the ring communication network for synchronizing others of the installations of communication equipment.

22. The apparatus of claim 21, further comprising:

a quality monitor to monitor a quality measure of the received network synchronization information,

wherein the received network synchronization information comprises multiple sets of redundant synchronization information,

wherein one of the multiple sets of redundant synchronization information is selected for use as basis for the local synchronization information responsive to a monitoring result, and

wherein the multiple sets of redundant synchronization information comprise network synchronization information being transferred in opposite directions in the ring communication network.

23. The apparatus of claim 1, wherein the synchronization information receiver receives an analog frequency reference signal, the analog frequency reference signal comprising the network synchronization information, and wherein the synchronization information distributor is further operable to pass the analog frequency reference signal for transmission to further communication equipment for synchronizing the further communication equipment with the communication network.

24. The apparatus of claim 1, wherein the network communication link comprises an optical communication link, and wherein the synchronization information receiver receives a frequency reference signal on a dedicated wavelength of the optical communication link, the received frequency reference signal comprising the network synchronization information.

25. The apparatus of claim 24, further comprising:

a quality monitor to monitor a quality measure of the received network synchronization information, and to report a monitoring result via the dedicated wavelength.

26. The apparatus of claim 25, wherein the quality monitor is operable to use the frequency reference signal as a messaging channel to report the monitoring result.

27. The apparatus of claim 24, wherein the optical communication link comprises an optical collector ring.

28. The apparatus of claim 1, implemented in conjunction with a ring network in which at least one of traffic channels and bandwidths are asymmetric.

29. A communication system comprising:

a gateway node operatively coupled to a main communication network through a bonded or optical communication link;

at least one subscriber node, operatively coupled to the gateway node, to provide a communication service to subscriber premises; and

at least one installation of communication equipment, respectively operatively coupled to a subscriber node of the at least one subscriber node,

wherein any or all of the gateway node and at least one subscriber node comprises the apparatus of claim 1.

30. The communication system of claim 29, further comprising:

at least one further gateway node operatively coupled to the gateway node through a respective bonded or optical communication link;

a respective set of at least one further subscriber node, respectively operatively coupled to the at least one gateway node, to provide a communication service to further subscriber premises; and

at least one further installation of communication equipment, respectively operatively coupled to a subscriber node of the at least one further subscriber node,

wherein any or all of the at least one further gateway node and the at least one further subscriber node comprises the apparatus of claim 1.

31. A method comprising:

receiving network synchronization information from a network communication link that enables communications with a communication network, the received network synchronization information for synchronizing communication equipment with the communication network; and

providing, based on the received network synchronization information, local synchronization information for synchronizing the communication equipment with the communication network.

32. The method of claim 31, further comprising:

providing, based on the received network synchronization information, remote synchronization information for transmission to further communication equipment, the remote synchronization information for synchronizing the further communication equipment with the communication network.

33. The method of claim 32, wherein the received network synchronization information comprises a synchronization packet, wherein the synchronization packet has a first priority, and wherein providing the remote synchronization information comprises generating the remote synchronization information by changing the priority of the synchronization packet to a second priority.

34. The method of claim 32, wherein the received network synchronization information comprises a synchronization packet, wherein providing the local synchronization information comprises providing the synchronization packet as the local synchronization information, and wherein providing the remote synchronization information comprises generating as the remote synchronization information a frequency reference standard based on the received synchronization packet.

35. The method of claim 32, wherein the received network synchronization information comprises a frequency reference signal, wherein providing the local synchronization comprises providing the frequency reference signal as the local synchronization information, and wherein providing the remote synchronization information comprises generating as the remote synchronization information a synchronization packet based on the received frequency reference signal.

36. The method of claim 31, further comprising:

monitoring a quality measure of the received network synchronization information; and

reporting a monitoring result via the network communication link.

37. The method of claim 32, further comprising:

monitoring a quality measure of the received network synchronization information; and

at least one of;

receiving quality monitoring information associated with the remote synchronization information and reporting a monitoring result to the further communication equipment.

38. The method of claim 37, further comprising:

detecting a quality problem with the remote synchronization information based on the received quality monitoring information; and

performing, responsive to detecting the quality problem, at least one of;

causing a characteristic of the remote synchronization information to be adjusted and reporting the quality problem via the network communication link.

39. The method of claim 31, wherein the received network synchronization information comprises multiple sets of redundant synchronization information, the method further comprising:

monitoring a quality measure of the sets of redundant synchronization information; and

selecting one of the multiple sets of redundant synchronization information for use as basis for the local synchronization information responsive to a result of the monitoring.

40. The method of claim 32, further comprising:

transmitting the remote synchronization information through at least one of;

a ring communication network, a bonded communication link, an optical communication link, and a wireless communication link.

41. The method of claim 32, further comprising:

transmitting the remote synchronization information using one or more of;

RPR (Resilient Packet Ring), Ethernet, and VDSL2 (Very high bit rate Digital Subscriber Line version

     2).

42. The method of claim 31, wherein the network communication link comprises a bonded DSL (Digital Subscriber Line) link.

43. The method of claim 32, wherein providing the local synchronization information and providing the remote synchronization information comprise providing the local synchronization information and providing the remote synchronization information based on the received network synchronization information where no new network synchronization information is received during a holdover time period.

44. The method of claim 31, wherein the network communication link comprises a bonded communication link, and wherein receiving comprises isolating a frequency reference signal from a DSL (Digital Subscriber Line) communication link which is a constituent link of the bonded communication link, the received frequency reference signal comprising the network synchronization information.

45. The method of claim 44, further comprising:

monitoring a quality measure of the received network synchronization information; and

using the frequency reference signal as a messaging channel to report a monitoring result.

46. The method of claim 44, wherein isolating comprises isolating respective frequency reference signals from multiple DSL communication links of the bonded communication link, the method further comprising:

monitoring a quality measure of the respective frequency reference signals; and

selecting one of the redundant frequency reference signals for use as basis for the local synchronization information responsive to a result of the monitoring.

47. The method of claim 46, wherein the quality measure comprises respective error rates of the redundant frequency reference signals, wherein selecting comprises selecting the redundant frequency reference signal having a lowest error rate, and wherein the method further comprises:

determining the respective error rates based on a PRBS (Pseudo-Random Bit Sequence) that is combined with the redundant frequency reference signals.

48. The method of claim 44, wherein the received frequency reference signal comprises DSL traffic being transferred on the DSL communication link, and wherein the local synchronization information comprises a clock signal recovered from the DSL traffic.

49. The method of claim 31,

wherein the network synchronization information comprises network synchronization information being transferred in a ring communication network that is operatively coupled to the communication network, the received network synchronization information for synchronizing, with the communication network, installations of communication equipment that are operatively coupled to the ring communication network,

wherein the communication equipment comprises one of the installations of communication equipment operatively coupled to the ring communication network, and

wherein the method further comprises providing the received synchronization information for transmission in the ring communication network for synchronizing others of the installations of communication equipment.

50. The method of claim 49, wherein the received network synchronization information comprises multiple sets of redundant synchronization information, the method further comprising:

monitoring a quality measure of the received network synchronization information; and

selecting one of the multiple sets of redundant synchronization information for use as basis for the local synchronization information responsive to a result of the monitoring,

wherein the multiple sets of redundant synchronization information comprise network synchronization information being transferred in opposite directions in the ring communication network.

51. The method of claim 31, wherein receiving comprises receiving an analog frequency reference signal, the analog frequency reference signal comprising the network synchronization information, the method further comprising:

passing the analog frequency reference signal for transmission to further communication equipment for synchronizing the further communication equipment with the communication network.

52. The method of claim 31, wherein the network communication link comprises an optical communication link, and wherein receiving comprises receiving a frequency reference signal on a dedicated wavelength of the optical communication link, the received frequency reference signal comprising the network synchronization information.

53. The method of claim 52, further comprising:

monitoring a quality measure of the received network synchronization information; and

reporting a result of the monitoring via the dedicated wavelength.

54. The method of claim 53, wherein reporting comprises using the frequency reference signal as a messaging channel to report the monitoring result.

55. The method of claim 52, wherein receiving comprises receiving respective frequency reference signals from multiple dedicated wavelengths of the optical communication link, the method further comprising:

monitoring a quality measure of the received network synchronization information; and

selecting one of the redundant frequency reference signals for use as basis for the local synchronization information responsive to a result of the monitoring.

56. The method of claim 52, wherein the optical communication link comprises an optical collector ring.

57. An apparatus comprising:

a communication interface to enable communications in a ring communication network; and

a traffic processor operatively coupled to the communication interface to process communication traffic being transferred in the ring communication network, the communication traffic comprising communication traffic destined for wireless communication devices to which a wireless communication service is provided within respective service areas by respective synchronized installations of wireless communication equipment that are operatively coupled to the ring communication network, the traffic processor being operable to detect movement of a wireless communication device from a service area of one of the synchronized installations of wireless communication equipment to a service area of another one of the synchronized installations of wireless communication equipment, and to provide a predictive traffic forwarding function for communication traffic destined for the wireless communication device based on the detected movement.

58. The apparatus of claim 57, wherein the traffic processor is operable to detect movement of the wireless communication device based on communication traffic that originates with the wireless communication device and is transferred in the ring communication network.

59. The apparatus of claim 57, wherein the predictive traffic forwarding function controls one or more of:

a network element of the ring communication network to which the communication traffic destined for the wireless communication device is forwarded and a direction in which the communication traffic destined for the wireless communication device is forwarded in the ring communication network.

60. The apparatus of claim 57, implemented at each of a plurality of ring nodes comprising the ring communication network.

61. The apparatus of claim 57, wherein the ring network comprises a plurality of ring nodes, at least one of the plurality of ring nodes being operatively coupled to a bonded communication link to a main communication network, the apparatus being implemented at each of the at least one of the plurality of ring nodes that is operatively coupled to the bonded communication link.

62. The apparatus of claim 57, wherein the apparatus is implemented at each of the plurality of ring nodes.

63. A method comprising:

detecting movement of a wireless communication device, to which a wireless communication service is provided within respective service areas by respective synchronized installations of wireless communication equipment that are operatively coupled to a ring communication network, from a service area of one of the synchronized installations of wireless communication equipment to a service area of another one of the synchronized installations of wireless communication equipment; and

providing a predictive traffic forwarding function for communication traffic destined for the wireless communication device based on the detected movement.