OPTICAL BACKHAUL NETWORK FOR WIRELESS BROADBAND SERVICE

• US 20110188858A1
• Filed: 07/07/2008
• Published: 08/04/2011
• Est. Priority Date: 06/25/2008
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Park, Man Yong, Kim, Bong Tae, Lee, Han Hyub, Kim, Byoung Whi
• Granted Patent: US 8,705,969 B2
• Time in Patent Office: Days
• US Class Current: 398/66
• CPC Class Codes: H04B 10/25754 Star network topology
• CPC Class Codes: H04J 14/0204 Broadcast and select arrangements, e.g. with an optical splitter at the input before adding or dropping
• CPC Class Codes: H04J 14/0209 Multi-stage arrangements, e.g. by cascading multiplexers or demultiplexers
• CPC Class Codes: H04J 14/0213 Groups of channels or wave bands arrangements
• CPC Class Codes: H04J 14/0216 Bidirectional architectures
• CPC Class Codes: H04J 14/0232 for downstream transmission
• 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 14/028 WDM bus architectures
• CPC Class Codes: H04J 14/0282 WDM tree architectures
• CPC Class Codes: H04J 2014/0253 Allocation of downstream wavelengths for upstream transmission

Abstract

An optical backhaul network for a wireless broadband service is provided. The optical backhaul network for a wireless broadband service includes: a plurality of optical network units for outputting an uplink optical signal having a multiplexed wavelength; an optical line termination for outputting a downlink optical signal of a single mode in order to transmit the downlink optical signal to the plurality of the optical network units in a broadcasting form; and a plurality of remote nodes for outputting a part of the downlink optical signal to the plurality of the optical network units and for outputting the uplink optical signal to the optical line termination. Therefore, one center and a plurality of access points can be efficiently connected.

Claims

1. An optical backhaul network for a wireless broadband service, comprising:

a plurality of optical network units (ONUs) outputting an uplink optical signal having a multiplexed wavelength;

an optical line termination (OLT) for outputting a downlink optical signal of a single mode in order to transmit the downlink optical signal to the ONUs in a broadcasting form; and

a plurality of remote nodes (RNs) for outputting a part of the downlink optical signal to the ONUs and for outputting the uplink optical signal to the OLT.

2. The optical backhaul network of claim 1, wherein the downlink optical signal of a single mode and the plurality of uplink optical signals use different independent optical wavelengths.

3. The optical backhaul network of claim 1, wherein the OLT further outputs a seed light signal having a multiplexed optical wavelength, and

the uplink optical signal is generated using the seed light signal.

4. The optical backhaul network of claim 3, wherein the RN divides wavelengths of the downlink optical signal, transmits a part thereof to the RN after sequentially connecting, and transmits another part to the ONUs connected to the corresponding RN,

the RN divides wavelengths of the seed light signal and transmits a specified seed light signal to the ONUs connected to the corresponding RN, and

the RN multiplexes a wavelength of the uplink optical signal and transmits the uplink optical signal to the OLT.

5. The optical backhaul network of claim 3, wherein the RN and the ONU are connected through one optical fiber, and

the uplink optical signal, the seed light signal, and the downlink optical signal are transferred through the optical fiber.

6. The optical backhaul network of claim 5, wherein the ONU comprises:

an optical receiver for receiving the downlink optical signal of the single mode and restoring downlink information;

an optical transmitter for transmitting the uplink optical signal generated using the seed light signal; and

an optical filter for transferring the downlink optical signal to the optical receiver and transferring the uplink optical signal to the RN.

7. The optical backhaul network of claim 6, wherein the optical transmitter comprises a reflective semiconductor optical amplifier.

8. The optical backhaul network of claim 5, wherein the RN comprises:

an ADD-DROP filter for dividing optical wavelengths of the input downlink seed light, outputting a part thereof in order to transfer to the ONU, outputting another part thereof in order to transfer to the connected next RN, and multiplexing wavelengths of the uplink optical signal from the next RN and the uplink optical signal from the ONU and outputting the wavelengths in order to transfer to the OLT;

an optical power splitter for separating optical power of the downlink optical signal and outputting the optical power in order to transfer to each of the ONUs; and

an optical filter for being connected between the ADD-DROP filter and the optical power splitter to transfer the uplink optical signal and the downlink optical signal.

9. The optical backhaul network of claim 8, wherein the downlink optical signal from the optical power splitter provided in the RN is transferred to the ONUs in a broadcasting form, and

the ONUs output the uplink optical signal consisting of each specified optical wavelength.

10. The optical backhaul network of claim 3, wherein the RN and the ONU are connected through two optical fibers, and the uplink optical signal, the seed light, and the uplink optical signal are transferred through different optical fibers.

11. The optical backhaul network of claim 10, wherein the ONU comprises:

an optical receiver for receiving the downlink optical signal of the single mode and restoring downlink information; and

an optical transmitter for transmitting the generated uplink optical signal using the seed light signal.

12. The optical backhaul network of claim 11, wherein the optical transmitter comprises a reflective semiconductor optical amplifier.

13. The optical backhaul network of claim 10, wherein the RN comprises:

a ADD-DROP filter for separating an optical wavelength of the input downlink seed light, outputting a part thereof in order to transfer to the ONU, outputting another part thereof in order to transfer to the connected next RN, and multiplexing wavelengths of the uplink optical signal from the next RN and the uplink optical signal from the ONU and outputting the wavelengths in order to transfer to the OLT; and

an optical power splitter for separating optical power of the downlink optical signal and outputting the optical power in order to transfer to each of the ONUs.

14. The optical backhaul network of claim 13, wherein the downlink optical signal from the optical power splitter provided in the RN is transferred to the ONUs in a broadcasting form, and

the ONUs output the uplink optical signal consisting of each specified optical wavelength.

15. The optical backhaul network of claim 3, further comprising an optical power splitter for being connected between the RN and the ONU to separate and transfer optical power of the downlink optical signal from the RN.

16. The optical backhaul network of claim 15, wherein the ONU receives an optical broadcasting signal, and

the OLT receives a wavelength division multiple packet as the uplink optical signal.

17. The optical backhaul network of claim 1, wherein the OLT comprises:

a seed optical module for outputting a seed optical signal having a multiplexed wavelength;

an optical transmitter for transmitting the downlink optical signal of the single mode;

an optical wavelength demultiplexer for separating wavelengths of the uplink optical signal having different wavelengths;

an optical receiver for receiving the uplink optical signal having a separated wavelength;

an optical filter for coupling the seed optical signal and the downlink optical signal; and

an optical circulator for transferring the coupled seed optical signal and downlink optical signal to the RN and for transferring the uplink optical signal to the optical wavelength demultiplexer.