Broadband optical network apparatus and method

• US 7,181,142 B1
• Filed: 04/09/2002
• Issued: 02/20/2007
• Est. Priority Date: 04/09/2002
• Status: Expired due to Term

• Current Assignee: Time Warner Cable Enterprises LLC (Charter Communications Incorporated)
• Original Assignee: Time Warner Cable Inc. (Charter Communications Incorporated)
• Inventors: Xu, Jun, Qian, Nanjian
• Primary Examiner(s): Payne; David C.
• Application Number:
  US10/120,960
• Time in Patent Office: 1,778 Days
• Field of Search: 398 58- 64, 398/66
• US Class Current: 398/66
• CPC Class Codes: H04B 10/27 Arrangements for networking
• CPC Class Codes: H04J 14/086 Medium access H04J3/16 takes precedence
• CPC Class Codes: H04J 3/14 Monitoring arrangements for SDH/SONET rings H04J3/085
• CPC Class Codes: H04J 3/1694 Allocation of channels in TDM/TDMA networks, e.g. distributed multiplexers Passive Optical Networks H04Q11/0062
• CPC Class Codes: H04Q 11/0066 Provisions for optical burst or packet networks
• CPC Class Codes: H04Q 11/0067 Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring
• CPC Class Codes: H04Q 2011/0015 using splitting combining
• CPC Class Codes: H04Q 2011/0064 Arbitration, scheduling or medium access control aspects

Abstract

Methods and apparatus for providing enhanced optical networking service and performance which are particularly advantageous in terms of low cost and use of existing infrastructure, access control techniques, and components. In the exemplary embodiment, current widespread deployment and associated low cost of Ethernet-based systems are leveraged through use of an Ethernet CSMA/CD MAC in the optical domain on a passive optical network (PON) system. Additionally, local networking services are optionally provided to the network units on the PON since each local receiver can receive signals from all other users. An improved symmetric coupler arrangement provides the foregoing functionality at low cost. The improved system architecture also allows for fiber failure protection which is readily implemented at low cost and with minimal modification.

Claims

1. A method of bandwidth arbitration among a plurality of network units of a broadband optical network, said optical network having at least first and second optical couplers and an access protocol, the method comprising:

splitting first optical signals derived from at least one of said network units at said at least first coupler to produce at least second and third signals;

splitting at least a portion of said second signals using said second coupler;

distributing at least a portion of said split second signals to each of said plurality of network units;

determining at each of said plurality of network units whether said at least portion of said split optical signal is present; and

permitting the respective ones of said plurality of network units to transmit optical signals onto said network only when said at least portion of said split signal is not detected for an interval, said interval comprising an amount of time that equals or exceeds an inter-frame gap;

wherein said act of splitting first optical signals comprises splitting a plurality of first signals derived from respective ones of said plurality of network units.

2. The method of claim 1, wherein said act of splitting first optical signals comprises splitting upstream signals, and said act of splitting said second signals comprises splitting downstream signals.

3. The method of claim 2, wherein said act of splitting first optical signals to produce at least second and third signals comprises splitting said first signals into two components having substantially equal power.

4. The method of claim 1, further comprising:

monitoring for said at least portion of said split signal after said act of permitting; and

transmitting a collision enforcement signal when a collision between said at least portion and said optical signals transmitted from the monitoring network unit is detected.

5. The method of claim 1, further comprising balancing the optical power levels of said optical signals produced by said plurality of network units.

6. An optical network, comprising:

a first node being adapted for transmitting and receiving optical signals, said first node comprising;

(i) an optical transceiver for transmitting and receiving data frames, and (ii) an optical transmitter for transmitting video signals;

a first optical coupler in optical communication with said first node and adapted to split signals received by said first coupler;

a second optical coupler in optical communication with said first node and adapted to split signals received by said second coupler, said second coupler also being in optical communication with said first coupler; and

a plurality of second nodes in optical communication with both said first and second couplers, said plurality of second nodes each being adapted for transmitting and receiving optical signals, said plurality of second nodes each comprising;

(i) a first interface adapted to receive and transmit data frames, and (ii) a second interface adapted to receive said video signals;

wherein said first coupler may be used to split signals received from at least one of said second nodes and communicate said signals to at least another of said nodes via said second coupler.

7. The network of claim 6, wherein said plurality of second nodes further comprise a third interface adapted to:

(a) communicate with other ones of said second nodes; and

(b) receive optical signals useful in collision detection between two or more of said second nodes.

8. The network of claim 6, further comprising first and second single mode feeder fibers providing said optical communication between said first node and said first and second optical couplers, respectively.

9. The network of claim 8, further comprising a plurality of distribution fibers providing said optical communication between said first and second couplers and said plurality of second nodes.

10. The network of claim 6, wherein the transmission of optical signals generated by said plurality of second nodes are arbitrated according to an access protocol.

11. The network of claim 10, wherein said access protocol comprises a CSMA/CD protocol.

12. The network of claim 10, wherein the domain of said access protocol comprises only said plurality of second nodes.

13. A broadband optical network having a plurality of network units and utilizing an access protocol, the broadband optical network comprising:

means for splitting first optical signals derived from at least one of said network units to produce at least second and third signals, said means for splitting first optical signals comprising means for splitting a plurality of said first signals derived from respective ones of said plurality of network units;

means for splitting at least a portion of said second signals;

means for distributing at least a portion of said split second signals to at least one of said plurality of network units;

means for determining at each of said plurality of network units whether said at least portion of said split second signal is present; and

means for permitting the respective ones of said plurality of network units to transmit optical signals onto said network only when said at least portion of said split second signal is not detected for an interval;

wherein said means for distributing is adapted to distribute said split second signals to each of said plurality of network units, and wherein said means for permitting is adapted to permit transmission when said interval comprises an amount of time that equals or exceeds an inter-frame gap (IFG).

14. The network of claim 13, further comprising:

means for monitoring for said at least portion of said split second signals after said transmission; and

means for transmitting a collision enforcement signal when a collision between said at least portion and said optical signals transmitted from the monitoring network unit is detected.

15. An optical network, comprising:

means for transmitting and receiving optical signals comprising;

(i) an optical transceiver for transmitting and receiving data frames, and (ii) an optical transmitter for transmitting video signals;

first coupling means optically coupled to said means for transmitting and adapted to split signals received by said first coupling means;

a second coupling means optically coupled to said means for transmitting and adapted to split signals received by said second coupling means, said second coupling means also being in optical communication with said first coupling means; and

a plurality of nodes in optical communication with both said first and second coupling means, said plurality of nodes each being adapted for transmitting and receiving optical signals;

wherein said first coupling means may be used to split signals received from at least one of said nodes and communicate said signals to at least another of said nodes via said second coupling means.

16. The network of claim 15, wherein said plurality of second nodes each comprise:

(i) a first interface adapted receive and transmit data frames; and

(ii) a second interface adapted to receive said video signals.

17. The network of claim 16, wherein said plurality of nodes further comprise a third interface adapted to:

(a) communicate with other ones of said nodes; and

(b) receive optical signals useful in collision detection between two or more of said nodes.

18. A method of bandwidth arbitration among a plurality of network units associated with an optical network, said optical network having at least first and second optical couplers and an access protocol, the method comprising:

splitting first optical signals derived from at least one of said network units at said at least first coupler to produce at least second and third signals, said splitting first optical signals comprising splitting a plurality of first signals derived from respective ones of said plurality of network units;

splitting at least a portion of said second signals using said second coupler;

distributing at least a portion of said split second signals to each of said plurality of network units;

determining via each of said plurality of network units the absence of said at least portion of said split optical signal; and

permitting the respective ones of said plurality of network units to transmit optical signals onto said network only in the absence of said at least portion of said split signal for an interval, said interval comprising an amount of time that equals or exceeds an inter-frame gap.

19. The method of claim 18, wherein said act of splitting first optical signals comprises splitting upstream signals, and said act of splitting said second signals comprises splitting downstream signals.

20. The method of claim 18, wherein said act of splitting first optical signals to produce at least second and third signals comprises splitting said first signals into two components having substantially equal power.

21. The method of claim 18, further comprising:

monitoring for said at least portion of said split signal after said act of permitting; and

transmitting a collision enforcement signal when a collision between said at least portion and said optical signals transmitted from the monitoring network unit is detected.

22. The method of claim 18, further comprising balancing the optical power levels of said optical signals produced by said plurality of network units.

23. An optical network, comprising:

a first node adapted to transmit and receive optical signals, said first node comprising an optical transceiver adapted to transmit and receive data frames, and an optical transmitter adapted to transmit video signals;

a first optical coupler in communication with said first node and adapted to split signals received by said first coupler;

a second optical coupler in communication with said first node and adapted to split signals received by said second coupler, said second coupler also being in optical communication with said first coupler; and

a plurality of second nodes in communication with both said first and second couplers, said plurality of second nodes each being adapted to transmit and receive optical signals, said plurality of second nodes each comprising;

(i) a first interface adapted to receive and transmit data frames, and (ii) a second interface adapted to receive said video signals;

wherein said first coupler may be used to split signals received from at least one of said second nodes and communicate said signals to at least another of said nodes via said second coupler.

24. The network of claim 23, wherein said plurality of second nodes further comprise a third interface adapted to:

(a) communicate with other ones of said second nodes; and

(b) receive optical signals useful in collision detection between two or more of said second nodes.

25. The network of claim 23, further comprising first and second single mode feeder fibers providing said optical communication between said first node and said first and second optical couplers, respectively.

26. The network of claim 25, further comprising a plurality of distribution fibers providing said optical communication between said first and second couplers and said plurality of second nodes.

27. The network of claim 23, wherein the transmission of optical signals generated by said plurality of second nodes are arbitrated according to an access protocol.

28. The network of claim 27, wherein said access protocol comprises a CSMA/CD protocol.

29. The network of claim 27, wherein the domain of said access protocol comprises only said plurality of second nodes.