Single wavelength Bi-directional RoF link apparatus for signal transmission in TDD wireless system

• US 20070258432A1
• Filed: 12/20/2006
• Published: 11/08/2007
• Est. Priority Date: 05/03/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Jae-Hoon, Hwang, Seong-Taek, Kim, Sang-Ho, Kim, Byung-Jik
• Granted Patent: US 7,773,887 B2
• Time in Patent Office: Days
• US Class Current: 370/347
• CPC Class Codes: H04B 10/25758 between a central unit and a single remote unit by means of an optical fibre
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels

Abstract

A single wavelength bi-directional RoF link apparatus for signal transmission in a TDD wireless system includes a main donor for receiving an RF signal of downstream data from an upper layer, electrooptic converting the received RF signal to an optical signal, and transmitting the converted optical signal via an optical fiber in response to a TDD switching signal received from the upper layer, or receiving an optical signal of upstream data via the optical fiber, opto-electric converting the received optical signal to an RF signal in response to the TDD switching signal received from the upper layer, and transmitting the converted optical signal to the main donor; and a remote for receiving the optical signal of the downstream data via the optical fiber from the main donor, opto-electric converting the received optical signal to an RF signal, and emitting the converted RF signal to a terminal via an antenna in response to a TDD switching signal generated by a switch timing signal generation circuit, or receiving an RF signal of upstream data from the terminal, electro-optic converting the received RF signal to an optical signal in response to the TDD switching signal generated by the switch timing signal generation circuit, and transmitting the converted optical signal to the main donor via the optical fiber.

Claims

1. A single wavelength bi-directional Radio over Fiber (RoF) link apparatus for signal transmission in a Time Division Duplexing (TDD) wireless system, the RoF link apparatus comprising:

a main donor comprising a receiving unit and a transmission unit, the receiving unit for;

receiving a Radio Frequency (RF) signal of downstream data from an upper layer,

electro-optic converting the received RF signal to an optical signal, and

transmitting the converted optical signal via an optical fiber in response to a TDD switching signal received from an upper layer; and

the transmission unit for;

receiving an optical signal of upstream data via the optical fiber,

opto-electric converting the received optical signal to an RF signal in response to the TDD switching signal received from the upper layer, and

transmitting the converted optical signal to the main donor; and

a remote comprising a receiving unit and transmission unit, the remote receiving unit;

receiving the optical signal of the downstream data via the optical fiber from the main donor,

opto-electric converting the received optical signal to an RF signal, and

emitting the converted RF signal to a terminal via an antenna in response to a TDD switching signal generated by a switch timing signal generation circuit, and the remote transmission unit for

receiving an RF signal of upstream data from the terminal,

electro-optic converting the received RF signal to an optical signal in response to the TDD switching signal generated by the switch timing signal generation circuit, and

transmitting the converted optical signal to the main donor via the optical fiber.

2. The RoF link apparatus of claim 1, wherein the upper layer is a base station of a mobile communication system, transmits data received from a Packet Access Router (PAR) to the terminal in a wireless manner, and has a low-power RF/Intermediate Frequency (IF) module and controller function, an Orthogonal Frequency Division Multiplexing (OFDM)/TDD packet scheduling and channel multiplexing function, a Media Access Control (MAC) frame variable control function according to a service characteristic and a radio wave environment, a 50 Mbps-level high-speed traffic real-time control function, and a handover function.

3. The RoF link apparatus of claim 1, wherein the main donor comprises:

a first low noise amplifier (LNA) for receiving an RF signal of downstream data from the upper layer via an RF cable, canceling a noise component of the RF signal, amplifying a signal component of the RF signal, and outputting the noise-cancelled and signal-amplified RF signal;

a first optical transmitter (Tx1) for receiving the RF signal from the first LNA, electrooptic converting the received RF signal to an optical signal, and outputting the converted optical signal;

a first optical switch for receiving an optical signal of downstream data from the Tx1 and an optical signal of upstream data via the optical fiber and selectively providing a path of the optical signal of the downstream data or the optical signal of the upstream data by controlling the opening and closing thereof in response to the TDD switching signal input from the upper layer;

a first optical receiver (Rx1) for opto-electric converting the optical signal of the upstream data input from the first optical switch to an RF signal and outputting the converted RF signal; and

a first high power amplifier (HPA) for amplifying the RF signal input from the Rx1 and transmitting the amplified RF signal to the upper layer via the RF cable.

4. The RoF link apparatus of claim 1, wherein the remote comprises:

an optical circulator for receiving the optical signal of the downstream data via the optical fiber and the optical signal of the upstream data from the second optical switch and controlling output paths of the optical signal of the downstream data and the optical signal of the upstream data;

a second optical receiver (Rx2) for receiving the optical signal of the downstream data, opto-electric converting the optical signal of the downstream data to an RF signal and outputting the converted RF signal;

a second HPA for receiving the RF signal of the downstream data from the Rx2, amplifying the RF signal

and transmitting the amplified RF signal;

a switch timing signal generation circuit for receiving a portion of the RF signal of the downstream data from the Rx2, generating a TDD switching signal, and outputting the generated TDD switching signal;

an electrical switch for receiving the RF signal of the downstream data from the second HPA and the RF signal of the upstream data from the terminal and selectively providing a path of the RF signal of the downstream data or the RF signal of the upstream data by controlling the opening and closing thereof in response to the TDD switching signal generated by the switch timing signal generation circuit;

a second LNA for receiving the RF signal of the upstream data from the electrical switch, substantially canceling a noise component of the RF signal, amplifying a signal component of the RF signal, and outputting the noise-cancelled and signal-amplified RF signal;

a second optical transmitter (Tx2) for receiving the RF signal of the upstream data from the second LNA, electrooptic converting the received RF signal to an optical signal, and outputting the converted optical signal; and

a second optical switch for receiving the optical signal of the upstream data from the Tx2 and providing the optical signal of the upstream data to the optical circulator by controlling the opening and closing thereof in response to the TDD switching signal generated by the switch timing signal generation circuit.

5. The RoF link apparatus of claim 4, wherein the optical circulator is a directional coupler having an isolation function.

6. The RoF link apparatus of claim 5, wherein the directional coupler is selected from the group consisting of:

an optical combiner, a Y-branch waveguide, and a 2×

1 directional coupler.

7. The RoF link apparatus of claim 4, wherein the optical circulator is a directional coupler.

8. The RoF link apparatus of claim 3, wherein the Tx1 is selected from the group consisting of:

a laser diode (LD) or light emitting diode (LED).

9. The RoF link apparatus of claim 3, wherein the Rx1 is a photo diode.

10. The RoF link apparatus of claim 4, wherein the Tx2 is selected from the group consisting of:

a laser diode (LD) or light emitting diode (LED).

11. The RoF link apparatus of claim 4, wherein the Rx2 is a photo diode.

12. A device suitable for use in an RoF network, comprising:

a low noise amplifier (LNA) receiving an RF signal of downstream data via an RF cable, and amplifying a signal component of the RF signal, and outputting signal-amplified RF signal;

an optical transmitter (Tx1) for receiving the RF signal from the LNA, converting the received RF signal to an optical signal, and outputting the converted optical signal;

a first optical switch receiving an optical signal of downstream data from the Tx1 and an optical signal of upstream data via the optical fiber and selectively providing a path of the optical signal of the downstream data or the optical signal of the upstream data by controlling the opening and closing thereof in response to a TDD switching signal input;

an optical receiver (Rx1) for converting the optical signal of the upstream data input from the first optical switch to an RF signal and outputting the converted RF signal; and

a high power amplifier (HPA) for amplifying the RF signal input from the Rx1 and transmitting the amplified RF signal to the upper layer via the RF cable.

13. The device of claim 12, wherein the Tx1 is selected from the group consisting of:

a laser diode (LD) and light emitting diode (LED).

14. The device of claim 13, wherein the Rx1 is a photo diode.

15. A device suitable for use in a RoF network, the device comprising:

an optical path controller for receiving an optical signal of the downstream data via the optical fiber and an optical signal of the upstream data from an optical switch and controlling output paths of the optical signal of the downstream data and the optical signal of the upstream data;

an optical receiver (Rx2) for receiving the optical signal of the downstream data, converting the optical signal of the downstream data to an RF signal and outputting the converted RF signal;

a high power amplifier (HPA) for receiving the RF signal of the downstream data from the Rx2, amplifying the RF signal and transmitting the amplified RF signal;

a switch timing signal generation circuit for receiving a portion of the RF signal of the downstream data from the Rx2, generating a TDD switching signal, and outputting the generated TDD switching signal;

an electrical switch for receiving the RF signal of the downstream data from the HPA and the RF signal of the upstream data and selectively providing a path for the RF signal of the downstream data and the RF signal of the upstream data by controlling the opening and closing thereof in response to the TDD switching signal generated by the switch timing signal generation circuit;

a low noise amplifier (LNA) for receiving the RF signal of the upstream data from the electrical switch, amplifying a signal component of the RF signal, and outputting the signal-amplified RF signal;

a optical transmitter (Tx2) for receiving the RF signal of the upstream data from the LNA, converting the received RF signal to an optical signal, and outputting the converted optical signal; and

an optical switch for receiving the optical signal of the upstream data from the Tx2 and providing the optical signal of the upstream data to the optical path controller by controlling the opening and closing thereof in response to the TDD switching signal generated by the switch timing signal generation circuit.

16. The device of claim 15, wherein the optical path controller is a directional coupler having an isolation function.

17. The device of claim 15, wherein the optical path controller is an optical circulator

18. The device of claim 15, wherein the directional coupler is selected from the group consisting of:

an optical combiner, a Y-branch waveguide, and a 2×

1 directional coupler.

19. The device of claim 15, wherein the Tx1 selected from the group consisting of:

a laser diode (LD) and light emitting diode (LED).

20. The device of claim 15, wherein the Rx1 is a photo diode.