ROF link system for supporting various services

• US 20070147273A1
• Filed: 12/05/2006
• Published: 06/28/2007
• Est. Priority Date: 12/22/2005
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Jae-Hoon, Hwang, Seong-Taek, Kim, Hoon, Kim, Sang-Ho, Kim, Byung-Jik, Kim, Sung-Kee, Lee, Han-Lim, Kim, Yong-Gyoo, Lee, Gyu-Woong
• Granted Patent: US 7,796,891 B2
• Time in Patent Office: Days
• US Class Current: 370/280
• CPC Class Codes: H04B 10/25758 between a central unit and a single remote unit by means of an optical fibre
• CPC Class Codes: H04H 20/69 Optical systems
• CPC Class Codes: H04H 20/71 Wireless systems
• CPC Class Codes: H04W 88/085 Access point devices with remote components
• CPC Class Codes: H04W 88/10 adapted for operation in multiple networks, e.g. multi-mode access points

Abstract

Disclosed is a radio-over-fiber (ROF) system for supporting various services, the system comprising: a central access platform (CAP) for providing time division duplexing (TDD), frequency division duplexing (FDD), and broadcasting services, converting a TDD downward signal and FDD/broadcasting downward signals into optical signals, respectively, transmitting the converted optical signals to a remote access unit (RAU), converting a TDD upward signal and an FDD upward signal, which have been transmitted as optical signals from the RAU, into electric signals, respectively, and using an optical circulator in order to separate upward and downward signals from each other; and the RAU for converting the TDD downward signal and FDD/broadcasting downward signals transmitted from the CAP into electric signals, respectively, converting the TDD upward signal and FDD upward signal to be transmitted to the CAP into optical signals, respectively, and using an optical circulator in order to separate upward and downward signals from each other, wherein the RAU includes a plurality of signal filtering/separating/combining units, which wirelessly emit the TDD downward signal and FDD/broadcasting downward signals, having been converted into electric signals, through an antenna, and which separate wirelessly-received TDD upward signal and FDD upward signal from each other.

Claims

1. A radio-over-fiber (ROF) system for supporting a plurality of services, the system comprising:

a central access platform (CAP) and a remote access unit (RAU);

the central access platform for;

providing time division duplexing (TDD), frequency division duplexing (FDD), and broadcasting services, converting a TDD downward signal and FDD/broadcasting downward signals into optical signals;

transmitting the converted optical signals to the remote access unit,

receiving optical signals from the RAU;

converting a TDD upward signal and an FDD upward signal in the receiving optical signals, into electric signals; and

separating the upward and downward signals from each other using an optical circulator; and

the remote access unit for;

converting the TDD downward signal and FDD/broadcasting downward signals transmitted from the CAP into electric signals,

converting the TDD upward signal and FDD upward signal to be transmitted to the CAP into optical signals and separating upward and downward signals from each other using an optical circulator,

wherein the RAU includes a plurality of signal filtering/separating/combining units, which wirelessly emit the converted TDD downward signal and FDD/broadcasting downward electric signals through an antenna, and which separate wirelessly-received TDD upward signal and FDD upward signal from each other.

2. The system as claimed in claim 1, wherein a first optical fiber for transmitting the TDD upward signal and TDD downward signal and a second optical fiber for transmitting the FDD/broadcasting downward signals and FDD upward signal are separately constructed between the CAP and the RAU.

3. The system as claimed in claim 1, wherein each of the CAP and RAU includes a wavelength division multiplexer for transmitting signals through a single optical fiber between the CAP and the RAU.

4. The system as claimed in claim 1, wherein the CAP comprises:

first and second optical transmitters for electro-optically converting the TDD downward signal and FDD/broadcasting downward signals, respectively;

a first optical circulator for receiving the electro-optically-converted TDD downward signal through a first port of the first optical circulator, outputting the received TDD downward signal through a second port of the first optical circulator so as to transmit the received TDD downward signal to the RAU, and outputting a TDD upward signal, which has been received from the RAU, through a third port of the first optical circulator;

a second optical circulator for receiving the electro-optically-converted FDD/broadcasting downward signals through a first port of the second optical circulator, outputting the received FDD/broadcasting downward signals through a second port of the second optical circulator so as to transmit the received FDD/broadcasting downward signals to the RAU, and outputting an FDD upward signal, which has been received from the RAU, through a third port of the second optical circulator; and

first and second optical receivers for photo-electrically converting the TDD upward signal and FDD upward signal which have been transmitted from the first and second optical circulators, respectively.

5. The system as claimed in claim 1, wherein the RAU comprises:

a third optical circulator for receiving a TDD downward signal from the CAP through a second port of the third optical circulator and outputting the TDD downward signal through a third port of the third optical circulator, and receiving a TDD upward signal, which is to be transmitted to the CAP, through a first port of the third optical circulator and outputting the TDD upward signal through the second port of the third optical circulator;

a third optical receiver for photo-electrically converting the TDD downward signal output from the third optical circulator;

a first downward amplifier for amplifying the TDD downward signal output from the third optical receiver;

a first duplexer for receiving the TDD downward signal from the first downward amplifier through a first port of the first duplexer and emitting the TDD downward signal through an antenna connected with a second port of the first duplexer, outputting a TDD upward signal, which has been received from the antenna, through the first port of the first duplexer, outputting FDD/broadcasting downward signals, which have been received through a third port of the first duplexer, to the antenna through the second port of the first duplexer, and outputting an FDD upward signal, which has been received from the antenna, through the third port of the first duplexer;

a first upward amplifier for amplifying the TDD upward signal output from the first duplexer;

a third optical transmitter for outputting the TDD upward signal, which has been received from the first upward amplifier, to the third optical circulator;

a fourth optical circulator for receiving FDD/broadcasting downward signals from the CAP through a second port of the fourth optical circulator and outputting the FDD/broadcasting downward signals through a third port of the fourth optical circulator, and receiving an FDD upward signal, which is to be transmitted to the CAP, through a first port of the fourth optical circulator and outputting the FDD upward signal through the second port of the fourth optical circulator;

a fourth optical receiver for photo-electrically converting the FDD downward signal output from the fourth optical circulator;

a second downward amplifier for amplifying FDD/broadcasting downward signals output from the fourth optical receiver;

a second duplexer for receiving the FDD/broadcasting downward signals from the second downward amplifier through a first port of the second duplexer and outputting the FDD/broadcasting downward signals to the first duplexer through a third port of the second duplexer, and outputting the FDD upward signal, which has been received from the first duplexer, through the third port of the second duplexer;

a second upward amplifier for amplifying the FDD upward signal output from the second duplexer; and

a fourth optical transmitter for outputting the FDD upward signal, which has been output from the second upward amplifier, to the fourth optical circulator.

6. The system as claimed in claim 1, wherein the RAU comprises:

a third optical circulator for receiving a TDD downward signal from the CAP through a second port of the third optical circulator and outputting the TDD downward signal through a third port of the third optical circulator, and receiving a TDD upward signal, which is to be transmitted to the CAP, through a first port of the third optical circulator and outputting the TDD upward signal through the second port of the third optical circulator;

a third optical receiver for photo-electrically converting the TDD downward signal output from the third optical circulator;

a first downward amplifier for amplifying the TDD downward signal output from the third optical receiver;

a first duplexer for receiving the TDD downward signal from the first downward amplifier through a first port of the first duplexer and emitting the TDD downward signal through a first antenna connected with a second port of the first duplexer, outputting a TDD upward signal, which has been received from the first antenna, through the first port of the first duplexer, and outputting a broadcasting signal, which has been received through a third port of the first duplexer, to the first antenna through the second port of the first duplexer;

a first upward amplifier for amplifying the TDD upward signal output from the first duplexer;

a third optical transmitter for outputting the TDD upward signal, which has been received from the first upward amplifier, to the third optical circulator;

a fourth optical circulator for receiving FDD/broadcasting downward signals from the CAP through a second port of the fourth optical circulator and outputting the FDD/broadcasting downward signals through a third port of the fourth optical circulator, and receiving an FDD upward signal, which is to be transmitted to the CAP, through a first port of the fourth optical circulator and outputting the FDD upward signal through the second port of the fourth optical circulator;

a fourth optical receiver for photo-electrically converting the FDD downward signal output from the fourth optical circulator;

a second downward amplifier for amplifying FDD/broadcasting downward signals output from the fourth optical receiver;

a second diplexer for separating the FDD/broadcasting downward signals, which have been amplified by the second downward amplifier, into the FDD downward signal and the broadcasting signal, outputting the separated FDD downward signal to a first port of a third duplexer, and outputting the separated broadcasting signal to the third port of the first duplexer;

the third duplexer for outputting an FDD downward signal, which has been input through a third port of the third duplexer, to a second antenna through a second port of the second duplexer, and outputting an FDD upward signal, which has been received through the second port of the third duplexer from the second antenna, through the third port of the third duplexer;

a second upward amplifier for amplifying the FDD upward signal output from the third duplexer; and

a fourth optical transmitter for outputting the FDD upward signal, which has been output from the second upward amplifier, to the fourth optical circulator.

7. The system as claimed in claim 5, wherein transmission of the TDD upward signal and TDD downward signal between the first optical circulator of the CAP and the second optical circulator of the RAU is achieved through a first optical fiber, and transmission of the FDD/broadcasting downward signals and FDD upward signal between the first optical circulator of the CAP and the second optical circulator of the RAU is achieved through a second optical fiber.

8. The system as claimed in claim 5, wherein

the CAP further comprises:

a first wavelength division multiplexer for multiplexing/demultiplexing signals input to/output from the first and second optical circulators, and

the RAU further comprises;

a second wavelength division multiplexer for multiplexing/demultiplexing signals input to/output from the third and fourth optical circulators, and the first and second wavelength division multiplexers transmit optical signals through a single optical fiber to each other.

9. The system as claimed in claim 6, wherein transmission of the TDD upward signal and TDD downward signal between the first optical circulator of the CAP and the second optical circulator of the RAU is achieved through a first optical fiber, and transmission of the FDD/broadcasting downward signals and FDD upward signal between the first optical circulator of the CAP and the second optical circulator of the RAU is achieved through a second optical fiber.

10. The system as claimed in claim 6, wherein

the CAP further comprises:

a first wavelength division multiplexer for multiplexing/demultiplexing signals input to/output from the first and second optical circulators'"'"' and

the RAU further comprises;

a second wavelength division multiplexer for multiplexing/demultiplexing signals input to/output from the third and fourth optical circulators, and the first and second wavelength division multiplexers transmit optical signals through a single optical fiber to each other.

11. A hybrid ROF/optical transmitting/receiving device comprising:

a Time Division Duplexer (TDD) service processor generating and receiving TDD services;

an TDD optical converter receiving a TDD signal generated by the TDD service processor and providing an optically converted TDD signal to an input port of a first optical circulator;

an TDD electrical converter receiving an optical TDD signal provided by an output port of the first optical circulator and providing an electrical TDD signal to the TDD service processor;

wherein the first optical circulator transmits the optically converted TDD signal and receives an optical TDD signal via an input/output port of the first optical circulator;

an FDD service processor and a Broadcast service processor generating an FDD signal and a Broadcast signal;

an FDD/Broadcast optical converter receiving the FDD and Broadcast signals and providing an optically converted FDD/Broadcast signals to an input port of a second circulator;

an FDD electrical converter receiving an optical FDD signal and providing by an output port of the second optical circulator an electrical FDD signal to the FDD service processor, wherein the second optical circulator transmits the optically converted FDD/Broadcast signal and receives an optical FDD signal via an input/output port of the second optical circulator.

12. The device as recited in claim 11, wherein the input/output port of the first and second circulators are connected to corresponding optical fibers.

13. The device as recited in claim 11, further comprising:

a wavelength division multiplexer, wherein the input/output port of the first and second optical circulators are connected to the wavelength division mulitplexer.

14. A hybrid ROF/optical transmitting/receiving device comprising:

a first circulator receiving an optical TDD signal at an input/output port of the first circulator;

a TDD electrical converter connected to an output port of the first circulator, the converter converting the received optical TDD signal to an electrical TDD signal;

a first Duplexer receiving the electrical TDD signal and providing the electrical TDD signal to an antenna and receiving an upstream TDD signal provided by the antenna and providing the received upstream TDD signal to an electrical optical converter to convert the received upstream TDD signal to an optical signal which is applied to an input port of the first circulator;

a second circulator receiving an optical FDD/Broadcast signal via an input/output port;

a FDD/Broadcast optical converter for converting the received optical FDD/Broadcast signal to an electrical signal;

a second Duplexer receiving the electrical FDD/Broadcast signal and further receiving an upstream FDD signal and providing the received upstream FDD signal to an electrical converter for converting the received upstream FDD signal to an optical FDD signal, wherein the optical FDD signal is provided to an input port of the second circulator.

15. The device as recited in claim 14, wherein the input/output ports of the first and second circulator are in communication with first and second optical fibers.

16. The device as recited in claim 14, further comprising:

a wave division multiplexer wherein the input/output ports of the first and second circulator are in communication with the multiplexer.

17. The device as recited in claim 14, wherein the second Duplexer provides the electrical FDD/Broadcast signal to the first Duplexer and receives the upstream FDD signal from the first Duplexer.

18. The device as recited in claim 14, further comprising:

a third Duplexer in communication with FDD/Broadcast optical converter receiving the electrical FDD/Broadcast signal and providing the FDD signal to the second Duplexer and the Broadcast signal to the first Duplexer; and

a second antenna connected to the second Duplexer for transmitting the FDD signal and receiving the upstream FDD signal.