Method and system for providing low-cost high-speed data services

• US 6,493,335 B1
• Filed: 09/24/1996
• Issued: 12/10/2002
• Est. Priority Date: 09/24/1996
• Status: Expired due to Term

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Darcie, Thomas Edward, Gnauck, Alan H., Lu, Xiaolin, Woodward, Sheryl Leigh, Desai, Bhavesh
• Primary Examiner(s): RAO, SEEMA SRINIVAS
• Application Number:
  US08/718,853
• Time in Patent Office: 2,268 Days
• Field of Search: 370/229-231, 370/235-237, 370/248, 370/249, 370/438, 370/439, 370/445-448, 370/463, 370/480, 370/485, 370/496, 370/522, 370/524, 370/528, 370/486, 370/279, 370/285, 370/293, 370/312, 370/315, 370/327, 370/343, 370/344, 370/348, 370/432, 370/401, 725/127
• US Class Current: 370/344
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling
• CPC Class Codes: H04L 12/413 with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]

Abstract

A communication network uses intermediate nodes to resolve local traffic contention. Intermediate nodes receive upstream signals from end users, derive traffic information signals from the upstream signals, and transmit the traffic information signals to end users. By listening to the traffic information signals from the intermediate node, the end users know whether the upstream transmission channels are idle or busy, or whether a collision has occurred. The intermediate nodes derive and transmit the traffic information signals with or without the assistance of the central office or head end.

Claims

1. A method of operating a communication network comprising a central office and at least one intermediate node, the method comprising;

transmitting downstream signals from the central office to a plurality of end units;

receiving at the intermediate node upstream signals sent from the plurality of end units;

transmitting from the intermediate node traffic information signals derived from the received upstream signals to the plurality of end units, the traffic information signals being multi-level RF signals that represent a status of a channel; and

notifying each end unit of the end units whether any further upstream transmissions can be performed.

2. The method of claim 1, further comprising the step of generating the downstream traffic information signals at the intermediate node.

3. The method of claim 1, wherein the network is a standard Ethernet and wherein the intermediate nodes divide the network into several small cells, each intermediate node resolving contention locally and connecting to a distribution port of a switched bridger.

4. The method of claim 1, further comprising the steps of:

listening with each end unit to the downstream traffic information signals before transmitting upstream signals;

transmitting the upstream signals when the downstream traffic information signals indicate that upstream channels are idle or that it is permissible to transmit;

postponing transmission at each end unit when the traffic information signals indicate that the upstream channels are busy; and

continuously listening at each end unit to the traffic information signals when transmitting, and comparing the received downstream traffic information signals with the downstream signaling that each end unit expects would be derived from its own transmitted upstream signals, and wherein each end unit stops transmission and backs off when the expected and received signals are different.

5. The method of claim 1, wherein said step of transmitting from the intermediate node comprises the step of looping at least a portion of the upstream signals back to each end unit.

6. The method of claim 1, further comprising the step of generating one of:

a first signal type indicating that an upstream channel is idle;

a second signal type indicating that an upstream signal is detected; and

a third signal type indicating that more than one upstream signal has arrived at the intermediate node simultaneously, thereby indicating a collision.

7. The method of claim 6, wherein each end unit listens to traffic information signals before transmitting upstream signals and does not transmit upstream signals if the second or third signal type is detected.

8. The method of claim 6, wherein each end unit listens while transmitting and stops transmission and backs off if the third signal type is detected.

9. The method of claim 1, further comprising the steps of:

sending the traffic information signals from the plurality of end units upstream;

looping at least a portion of the traffic information signals downstream from the intermediate node;

listening, with the plurality of end units to the downstream traffic information signals; and

continuously transmitting upstream signals or transmitting upstream signals when the downstream traffic information signals provides a channel idle indication or permission to transmit indication and postponing transmission or backing off when the traffic information signals indicate busy or collision.

19. The method of claim 1, wherein the central office sends the downstream signals over a first communication path and the intermediate node sends the traffic information signals over a second communication path.

20. The method of claim 1, comprising sending the downstream signals from the central office and the traffic information signals from the intermediate node over a common communication path but on different RF channels.

21. The method of claim 1, comprising sending the downstream signals from the central office and traffic information signals from the intermediate node over a common communication path using one of different optical wavelengths and different codes.

22. The method of claim 1, further comprising the step of sending the downstream signals, traffic information signals, and upstream signals over at least one of optical fibers, coaxial cables, twisted pairs, and radio links.

23. The method of claim 1, wherein the downstream and upstream signals and the traffic information signals comprise at least one of coded baseband signals, uncoded baseband signals, and RF signals.

24. The method of claim 1, wherein the duration of the traffic information signals is larger than the maximum round trip delay between the intermediate node and a selected end unit.

25. The method of claim 1, comprising sending the downstream signals from the central office and the traffic information signals from the intermediate node over a common RF channel and transmitting the downstream signals with a interpacket space having a size such that the intermediate node can insert traffic information signals in the interpacket space.

26. The method of claim 1, wherein the central office sends downstream signals in certain time periods and the end units transmit upstream signals and the intermediate nodes insert traffic information signals in other time periods.

27. The method of claim 1, comprising transmitting the upstream signals over multiple channels, such that each end unit can dynamically choose a channel based on received traffic information signals.

28. The method of claim 1, further comprising the steps of:

sending priority signaling upstream from at least one selected end unit; and

looping the priority signaling downstream at the intermediate node to allow the selected end unit to have high priority for occupying a channel such that other end units have low priority to transmit on that channel.

29. The method of claim 1, further comprising the step of:

sending reservation signaling upstream from at least one selected end unit to allow the selected end unit to reserve time slots such that other end units cannot transmit during the time slots on a particular channel.

30. The method of claim 1, further comprising the step of using a standard Ethernet card in the end unit and transmitting Manchester coded signals directly over the network.

31. The method of claim 1, further comprising the step of using a standard Ethernet card and DC shifting the Manchester coded signals with a standard Ethernet transceiver to become two-level signals carried directly by an RF carrier over the network and detecting the RF signal and converting it back to three-level Manchester code.

32. The method of claim 1, further comprising the step of using an Ethernet card as an end unit by disabling a loop back function in order to allow independent upstream and downstream operation.

33. The method of claim 1, further comprising the steps of:

connecting a transceiver with the AUI port of an Ethernet card at an end unit;

interfacing a downstream channel from the transceiver to the Ethernet card using a Data_In circuit;

interfacing an upstream channel from the Ethernet card to the transceiver using a Data_Out circuit; and

interfacing a traffic information signaling channel from the Ethernet card to the transceiver using a Control_In circuit.

34. The method of claim 32, further comprising the step of transmitting the upstream signal from the end unit about 9.6 μ

s after an incoming packet ends independent of receiving functions.

35. The method of claim 1, comprising separating transmitting and receiving functions of an Ethernet card such that each end unit can transmit when the upstream channel is free.

36. The method of claim 35, further comprising the steps of:

connecting a transceiver with a first Ethernet chip;

interfacing a downstream channel to the end unit using a Data_In circuit of the first Ethernet chip; and

interfacing an upstream channel and traffic information signal channel from the end unit using a Data_Out and Control_In circuit, respectively, of a second Ethernet chip to enable independent two-way operation such that each end unit can transmit any time the upstream channel is free.

37. The method of claim 1, wherein a standard Ethernet switched bridger is used at the central office, and wherein each distribution port of the bridger is connected to each intermediate node and will be shared by multiple end units served by the intermediate node.

38. The method of claim 1, comprising using a standard Ethernet bridger at the central office and two 10BaseT transceivers also located at the central office such that an output pair from the bridger connects to a first transceiver'"'"'s input pair and an output pair of the first transceiver connects to a second transceiver input pair, wherein an output pair of the second transceiver connects to an input pair of the bridger to create a link-pulse loop to satisfy a link-integrity request of the bridger and the first and the second transceivers.

39. The method of claim 1, wherein the intermediate node and the central office are at the same location.

40. The method of claim 1, comprising transmitting over a mFN-HFC network, wherein the intermediate node is a mini-fiber node.

41. The method of claim 1, wherein the network is a conventional HFC network and the intermediate node is a coax amplifier that transmits the traffic information signaling downstream in one of a 5-40 MHz range and a conventional downstream frequency band of 50 MHz to 1 GHz.

42. The method of claim 1, wherein the network is conventional HFC or mFN-HFC, and the intermediate node is the fiber node.

43. The method of claim 1, wherein the network is an active star network and the intermediate node is a remote node such that the intermediate node sends a channel-busy traffic information signal to all users when one upstream line is active, and sends a collision traffic information signal to at least one user if more than one upstream line is active.

44. The method of claim 1, wherein the network is a passive optical network and the intermediate node is at least one of at least one optical splitter and at least one WDM splitter/router, and wherein the upstream and downstream signals use different wavelengths or RF carriers such that upstream light is collected at an unused trunk port of one of the at least one splitter and is routed downstream over one of the same fiber and a different fiber.

10. A method of operating a communication network comprising a central office and at least one intermediate node, the method comprising;

transmitting downstream signals from the central office to a plurality of end units;

receiving at the intermediate node upstream signals sent from the plurality of end units;

transmitting from the intermediate node traffic information signals derived from the received upstream signals to the plurality of end units, the traffic information signals being multi-level RF signals that represent a status of a channel;

receiving a data packet that represents an address from at least one end unit of the plurality of end units upstream at the intermediate node; and

transmitting the data packet representing the address downstream with the traffic information signal back to the at least one end unit so that the at least one end unit can determine whether to transmit additional data over the communication network.

11. The method of claim 10, further comprising the steps of:

comparing, at each end unit, the transmitted address with the received address; and

transmitting upstream signals with each end unit if the two addresses are the same and halting transmission if the two addresses are different.

12. The method of claim 10, further comprising the steps of:

sending the address followed by traffic information signaling out-of-band from the upstream signals and prior to sending the upstream signals from each end unit; and

echoing the address and traffic information signaling downstream from the intermediate node, wherein the end unit transmits upstream signals after receiving the correct address while continuously transmitting the traffic information signaling out-of-band.

13. The method of claim 12, wherein the end unit stops sending the traffic information signaling at a time Δ

T before finishing sending upstream signals, wherein the time Δ

T is equal to or smaller than the time duration of sending the address packet.

14. The method of claim 12, wherein the end unit stops sending the traffic information signaling before finishing sending upstream signals such that the duration of the address and signaling is substantially the same as the duration of the upstream signals.

15. The method of claim 12, wherein the end unit stops sending the upstream signals and traffic information signaling simultaneously.

16. The method of claim 12, further comprising the steps of:

beginning transmission of upstream signals from the end unit and simultaneously halting transmission of traffic information signaling from the end unit; and

continuously transmitting traffic information signals from the intermediate node, the traffic information signals derived from the upstream signals.

17. The method of claim 10, further comprising the step of simultaneously sending the address from an end unit with its upstream signal.

18. The method of claim 10, comprising sending the address in-band with the upstream signals.

45. A method of operating a communication network that includes a central office at least one intermediate node, the method comprising:

transmitting downstream signals from the central office to a plurality of end units;

receiving, at the intermediate node, upstream signals sent from the plurality of end units;

transmitting, from the intermediate node, traffic information signals derived from received upstream signals to the plurality of end units, the traffic signals being multi-level RF signals that represent a status of a channel;

listening to, with each of the end units, the downstream traffic information signals before transmitting the upstream signals;

transmitting the upstream signals when the downstream traffic information signals indicate that upstream channels are idle, or that it is permissible to transmit;

postponing transmission at each of the end units when the downstream traffic information signals indicate that the upstream channels are busy; and

continously listening at each of the end units to the downstream traffic information signals when transmitting, and comparing the received downstream traffic information signals with downstream signaling that each of the end units expects would be derived from its own transmitted upstream signals, and wherein each of the end units stops transmission and backs off when expected and received signals are different.

46. A communication network for communicating with a plurality of end units, the communication network comprising:

a central office for transmitting downstream signals to the plurality of end units and for receiving upstream signals sent by the plurality of end units;

at least one intermediate node positioned in the network, the intermediate node comprising, a traffic information signal transmission device that uses a portion of the upstream signals and transmits to the plurality of end units traffic information signals derived from the portion of the upstream signals received from the plurality of end units, wherein the traffic information signals comprise multi-level RF signals that represent a status of a channel for notifying each end unit of the end units whether any further upstream transmissions can be performed.

47. The network of claim 46, wherein the at least one intermediate node further comprises a traffic information signal generating device that generates the traffic information signals.

48. The network of claim 46, wherein the network is a standard Ethernet and wherein the intermediate nodes divide the network into several small cells such that each intermediate node resolves contention locally and connects to a distribution port of a switched bridger.

49. The network of claim 46, wherein each end unit listens to the downstream traffic information signals before transmitting upstream signals and transmits the upstream signals when the downstream traffic information signals indicate that the upstream channels are idle or that transmission is permissible, and waits when the traffic information signals indicate the upstream channels are busy, and wherein each end unit compares the received downstream traffic information signals with the downstream signaling that it expects would be derived from its own transmitted upstream signals, and wherein the end unit stops transmission and backs off when the expected and received signals are different.

50. The network of claim 46, wherein the intermediate node transmits the traffic information signals by looping at least a portion of the upstream signals back to each end unit.

51. The network of claim 46, wherein each intermediate node, upon receiving upstream signals, generates and transmits traffic information signals comprising one of:

a first signal type indicating that an upstream channel is idle;

a second signal type indicating that an upstream signal is detected; and

a third signal type indicating that more than one upstream signal has arrived at the intermediate node simultaneously, thereby indicating a collision.

52. The network of claim 51, wherein each end unit listens to traffic information signals before transmitting upstream signals and does not transmit upstream signals if the second or third signal type is detected.

53. The network of claim 51, wherein each at least one end unit listens while transmitting and stops transmission and backs off if the third signal type is detected.

54. The network of claim 46, further comprising:

a transmission device within each end unit that sends traffic information signals upstream;

looping means within the intermediate node for looping at least a portion of the traffic information signals downstream;

receiving apparatus within each end unit that listens to downstream traffic information signals; and

transmitting apparatus within each end unit that continuously transmits upstream signals or transmits upstream signals when the downstream traffic information signals provide a channel idle indication or permission to transmit indication and postpones transmission or backs off when the traffic information signals indicate busy or collision.

55. The network of claim 46, wherein an address of the at least one end unit is sent upstream to the intermediate node and the address is transmitted downstream back to the end unit.

56. The network of claim 55, wherein the end unit makes a comparison between the transmitted address and the received address and transmits upstream signals if the two addresses are the same and halts transmission if the two addresses are different.

57. The network of claim 55, wherein the upstream signals are transmitted simultaneously with the address of the end unit and other information sent by the end unit.

58. The network of claim 46, wherein the central office further comprises an Ethernet switched bridger having each distribution port connected with an intermediate node and shared by multiple end units served by the intermediate node.

59. The network of claim 46, further comprising a transceiver that connects with an AUI port on a standard Ethernet card at an end unit and interfaces using a downstream channel with a Data_In circuit and an upstream channel with a Data_Out circuit and a traffic information signaling channel using a Control_In circuit.

60. The network of claim 46, wherein a transceiver interfaces with a downstream channel using a Data_In circuit of a first Ethernet chip and the transceiver further interfaces with an upstream channel and traffic information signal channel using a Data_Out circuit and Control_In circuit, respectively, of a second Ethernet chip to enable independent two-way operation such that each end unit of the end units can transmit when the upstream channel is free.

61. The network of claim 46, comprising using a standard Ethernet bridger at the central office and two 10BaseT transceivers also located at the central office such that an output pair from the bridger connects to a first transceiver'"'"'s input pair and an output pair of the first transceiver connects to a second transceiver input pair, wherein an output pair of the second transceiver connects to the bridger'"'"'s input pair to create a link-pulse loop to satisfy link integrity requests of the bridger and the first and the second transceivers.

62. The network of claim 46, wherein the intermediate node and the central office are at the same location.

63. The network of claim 46, wherein the network is a mFN-HFC network, and the intermediate node is a mini-fiber node.

64. The communication network of claim 46, wherein the network is a conventional HFC network and the intermediate node is a coax amplifier that transmits traffic information signaling downstream in one of 5-40 MHz and conventional downstream frequency band of 50 MHz to 1 GHz.

65. The network of claim 46, wherein the network is one of conventional HFC and mFN-HFC, and the intermediate node is the fiber node.

66. The network of claim 46, wherein the network is an active star network and the intermediate node is a remote node that sends a channel-busy traffic information signal to all the users when one upstream line is active and sends a collision traffic information signal to at least one user if more than one upstream line is active.

67. The network of claim 46, wherein the network is a passive optical network and the intermediate node is at least one of at least one optical splitter and at least one WDM splitter/router, and wherein the upstream and downstream use different wavelengths or RF carriers such that the upstream light is collected at the at least one splitter'"'"'s unused trunk port and routed downstream over one of the same and a different fiber.