Hybrid analog/digital WDM access network with mini-digital optical node

• US 6,147,786 A
• Filed: 02/20/1998
• Issued: 11/14/2000
• Est. Priority Date: 02/20/1998
• Status: Expired due to Term

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Inventors: Pan, Jin-Yi
• Primary Examiner(s): Chan, Jason
• Assistant Examiner(s): SINGH, DALZID E
• Application Number:
  US09/027,259
• Time in Patent Office: 998 Days
• Field of Search: 359/118, 359/125, 455/5.1
• US Class Current: 398/1
• CPC Class Codes: H04B 10/27 Arrangements for networking
• CPC Class Codes: H04B 10/2755 Ring-type networks with a headend
• CPC Class Codes: H04J 14/0226 Fixed carrier allocation, e.g. according to service
• CPC Class Codes: H04J 14/0232 for downstream transmission
• CPC Class Codes: H04J 14/0246 using one wavelength per ONU
• CPC Class Codes: H04J 14/025 using one wavelength per ONU, e.g. for transmissions from-ONU-to-OLT or from-ONU-to-ONU
• CPC Class Codes: H04J 14/0282 WDM tree architectures
• CPC Class Codes: H04J 14/0283 WDM ring architectures
• CPC Class Codes: H04J 14/0286 WDM hierarchical architectures
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications

Abstract

A hybrid, bi-directional, analog/digital WDM access network system, for transmitting/receiving a wavelength of analog signals and a plurality of wavelengths of digital signals which are communicated between a network and a plurality of users, includes a feeder/de/multiplexer for converting the wavelength of analog signals into electrical signals and de/multiplexing the wavelengths of digital signals into a plurality of one-wavelength of digital signals; a plurality of mini-digital optical nodes connecting individually to the feeder/de/multiplexer via a plurality of optic fibers, respectively, each of the mini-digital optical nodes converting one of the one-wavelength of digital signals into electrical signals; and wherein the analog and digital converted electrical signals are transmitted to the user. A method of downstream transmission from the network to the users and a method of upstream transmission from the users to the network includes steps of communicating the signals among the feeder/de/multiplexer, mini-digital nodes, optic fibers, a coax cable and/or a digital line.

Claims

1. A hybrid analog/digital wavelength-division multiplexing access network system, comprising:

a network for transmitting at least one wavelength of analog signals and a first plurality of wavelengths of digital signals via a first optic fiber to a plurality of users wherein the analog signals and the digital signals have different wavelengths, and for receiving a second plurality of wavelengths of digital signals from the users wherein the second plurality of wavelengths of digital signals have the same wavelengths as the first plurality of wavelengths of digital signals, the network having a backbone containing at least the one wavelength of analog signals and the first plurality of wavelengths of digital signals, the network having at least one headend which accesses the backbone of the network;

a splitter/de/multiplexer, the first optic fiber extending between at least the one headend and the splitter/de/multiplexer, the first plurality of wavelengths of digital signals and the at least one wavelength of analog signals being transmitted from the headend to the splitter/de/multiplexer via the first optic fiber and the first plurality of wavelengths of digital signals being demultiplexed and split into a plurality of branches of optic fibers, the analog signals being transmitted to each of the branches;

a second optic fiber;

a feeder/de/multiplexer, the second optic fiber extending between the splitter/de/multiplexer and the feeder/de/multiplexer, the analog signals and the digital signals in one of the branches being transmitted from the splitter/de/multiplexer to the feeder/de/multiplexer, the analog signals in the branch being converted into electrical signals by the feeder/de/multiplexer, and the digital signals in the branch being demultiplexed by the feeder/de/multiplexer into a one-wavelength per optic fiber format;

a third optic fiber being a one-wavelength optic fiber;

a mini-digital optical node disposed near users, the one-wavelength optic fiber extending between the feeder/de/multiplexer and the mini-digital optical node for transmitting a one-wavelength of digital signals to the mini-digital optical node, wherein the digital signals being converted to electrical signals at the mini-digital optical node;

a coax cable, extending from the feeder/de/multiplexer to the user, the analog converted electrical signals being transmitted from the feeder/de/multiplexer to the user via the coax cable, the digital converted electrical signals being transmitted from the mini-digital optic node to the user via the coax cable.

2. The system of claim 1, wherein the second plurality of wavelengths of digital signals are transmitted from the splitter/de/multiplexer to the headend via a fourth optic fiber and are formed by combining/multiplexing branches of the digital signals, the wavelengths of digital signals being transmitted from the feeder/de/multiplexer via a fifth optic fiber, the feeder/de/multiplexer multiplexing branches of the one-wavelength of digital signals which are transmitted from the mini-digital optical node via a sixth optic fiber, the one-wavelength of digital signals being transmitted from the mini-digital optical node whereby the electrical signals transmitted by the user via the coax cable are converted.

3. The system of claim 2, wherein the fourth optic fiber is substantially parallel to the first optic fiber.

4. The system of claim 2, wherein the fifth optic fiber is substantially parallel to the second optic fiber.

5. The system of claim 2, wherein the sixth optic fiber is substantially parallel to the third optical fiber.

6. The system of claim 2, bandwidth of an upstream transmission from the users to the network can be in a range of 750-1000 MHz.

7. The system of claim 2, wherein in the upstream transmission, the digital signals are converted into the one-wavelength at the mini-digital optical node and are multiplexed with other one-wavelengths of digital signals at the feeder/de/multiplexer point.

8. The system of claim 2, wherein the first and fourth optic fibers contain the same number of digital wavelengths.

9. The system of claim 2, wherein the second and fifth optic fibers contain the same number of digital wavelengths.

10. The system of claim 2, wherein the third and sixth optic fibers contain the same number of digital wavelengths.

11. The system of claim 1, wherein between the mini-digital optical node and each of the users, a hybrid fiber/coax bus type of structure is formed.

12. The system of claim 11, further comprising a one-way filter disposed on the coax cable between the feeder/de/multiplexer and the user proximate the mini-digital optical node being adapted to prevent the digital signals, transmitted from the user traveling on the coax cable, from interfering the analog signals transmitted on the coax cable of the other branches.

13. The system of claim 1, wherein between the mini-digital optical node and each of the users, a switched digital video star type of structure is formed.

14. The system of claim 1, bandwidth of a downstream transmission from the network to the users can be in a range of 550-1000 MHz.

15. The system of claim 8, wherein in the downstream transmission, the analog signal is broadcast to each of the users with a same wavelength as on the network.

16. The system of claim 8, wherein in the downstream transmission, the digital signals with different wavelengths are demultiplexed at the feeder/de/multiplexer point into the one wavelength per optic fiber format such that only one wavelength of the digital signals is transmitted on the third optic fiber, and in the upstream transmission, signals with different wavelength per fiber are multiplexed at the feeder/de/multiplexer point.

17. The system of claim 1, wherein the analog signals are video signals, and the digital signals are baseband digital signals.

18. The system of claim 1, wherein power of the mini-digital optical node is supplied via the coax cable.

19. The system of claim 1, wherein the mini-digital optical node is adapted to be a personal communication system (PCS) base station.

20. A method of communicating at least one wavelength of analog signals and a plurality of wavelengths of digital signals between a network headend and a plurality of users, the analog signals and digital signals having different wavelengths, comprising the steps of:

transmitting the wavelengths of analog and digital signals from a network headend to a splitter/de/multiplexer via a first optic fiber;

splitting/demultiplexing the wavelengths of analog and digital signals into a plurality of branches, each of the plurality of branches being a second optic fiber;

transmitting the analog signals to each of the plurality of branches and the digital signals to at least one of the plurality of branches, and then both to a feeder/de/multiplexer;

converting the analog signals to electrical signals at the feeder/de/multiplexer;

demultiplexing the wavelengths of the digital signals in at least the one branch to a one-wavelength per optic fiber format at the feeder/de/multiplexer;

transmitting the converted analog signals to one of the users via a coax cable;

transmitting the demultiplexed digital signals to a mini-digital optical node disposed near users via a third optic fiber;

converting the digital signals to electrical signals; and

transmitting the electrical signals to the user.

21. The method of 10, further comprising the steps of:

transmitting the electrical signals from the user to the mini-digital optical node;

converting the electrical signals to the one-wavelength of digital signals to be transmitted via a fourth optic fiber at the mini-digital optical node;

transmitting the converted one-wavelength of digital signals from the mini-digital optical node to the feeder/de/multiplexer via the fourth optic fiber;

multiplexing the one-wavelength of digital signals from other users into a multi-wavelength per fiber format at the feeder/de/multiplexer;

transmitting the wavelengths of multiplexed digital signals from the feeder/de/multiplexer to the splitter/de/multiplexer via a fifth optic fiber;

combining/multiplexing the wavelengths of the digital signals from other branches at the splitter/de/multiplexer; and

transmitting the wavelengths of combined/multiplexed digital signals from the splitter/de/multiplexer to the network headend through a sixth optic fiber.

22. A network system for transmitting/receiving a wavelength of analog signals and a plurality of wavelengths of digital signals, which are bi-directionally communicated between a network and a plurality of users, comprising:

a feeder/de/multiplexer for receiving wavelength of analog signals and a plurality of wavelengths of digital signals via an optical fiber and converting the wavelength of analog signals into electrical signals and demultiplexing the plurality of wavelengths of digital signals into a plurality of one-wavelength of digital signals;

a plurality of mini-digital optical nodes disposed near users connecting to the feeder/de/multiplexer via a plurality of optic fibers, respectively, each of the plurality of mini-digital optical nodes converting one of the one-wavelength of digital signals into electrical signals; and

wherein the analog and digital converted electrical signals are transmitted to the users.

23. The network system of claim 22, wherein the analog and digital converted electrical signals are transmitted to the users via a coax cable.

24. The network system of claim 22, wherein the analog converted electrical signals are transmitted to the users via a coax cable, the digital converted electrical signals are transmitted to the user via a digital line.

25. The network system of claim 23, wherein electrical signals transmitted from the user via the coax cable are converted into the one-wavelength digital signals at the mini-digital optical node, the one-wavelength digital signals are transmitted to the feeder/de/multiplexer via a second optic fiber and multiplexed with the other one-wavelength digital signals from the other user at the feeder/de/multiplexer.

26. The network system of claim 24, wherein electrical signals transmitted from the user via the digital line are converted into the one-wavelength digital signals at the mini-digital optical node, the one-wavelength digital signals are transmitted to the feeder/de/multiplexer via a second optic fiber and multiplexed with the other one-wavelength digital signals from the other user at the feeder/de/multiplexer.

27. A method of communicating at least one wavelength of analog signals and a plurality of wavelengths of digital signals between a network headend and a plurality of users, the analog signals and digital signals having different wavelengths, comprising the steps of:

transmitting at least the one wavelength of analog signals and the wavelengths of digital signals from the network headend to a feeder/de/multiplexer via a first optic fiber;

converting the analog signals to electrical signals at the feeder/de/multiplexer and demultiplexing the wavelengths of digital signals in a one-wavelength per optic fiber format at the feeder/de/multiplexer;

transmitting the demultiplexed digital signals to a mini-digital optical node disposed near users via a second optic fiber;

converting the demultiplexed digital signals to electrical signals at the mini-digital optic node; and

transmitting the analog and digital converted electrical signals to the plurality of the users.

28. The method of 27, further comprising the steps of:

transmitting electrical signals from the users to the mini-digital optical node;

converting the electrical signals to the one-wavelength of digital signals to be transmitted via a second optic fiber at the mini-digital optical node;

transmitting the converted digital signals from the mini-digital optical node to the feeder/de/multiplexer via the second optic fiber;

multiplexing the one-wavelength of digital signals with those from the other users into a multi-wavelength per fiber format at the feeder/de/multiplexer; and

transmitting the wavelengths of multiplexed digital signals from the feeder/de/multiplexer to the network headend.