KR101738698B1 - Wired/wireless converged network applied wavelength division multiplexing and signal tansmitting method - Google Patents

Abstract

A wired / wireless convergence network and a signal transmission method to which a wavelength division multiplexing scheme is applied is disclosed. In a wired / wireless convergence network, the wired network includes an optical line terminal (OLT) and an optical network unit (ONU), and the wireless network transmits and receives optical signals through a public wireless interface (CPRI) And includes a controller REC and a radio equipment RE.

Description

TECHNICAL FIELD [0001] The present invention relates to a WIRED / WIRELESS CONVERGED NETWORK APPLIED WAVELENGTH DIVISION MULTIPLEXING AND SIGNAL TANSMITTING METHOD,

The present invention relates to a method and apparatus for transmitting signals between a wireless equipment controller (REC) and a wireless equipment (RE) in a wireless base station transmitting and receiving information through a wireless interface using a WDM scheme, which is a technology used in a wired optical network, The present invention relates to an apparatus and a method applied to an interface.

In a typical cellular radio system, the equipment unit of a wireless user communicates with one or more core networks via a Radio Access Network (RAN). Here, the equipment unit of the wireless user may be a mobile terminal such as a portable telephone and a notebook. Or the wireless user's equipment unit may be a fixed wireless device, such as an Access Point.

The wireless access network covers a geographical area that is divided into cell areas, and each cell area can receive wireless service by a wireless base station. The coverage of the cell is determined by the radio equipment located at the base station site.

Wireless base stations in conventional cellular communication systems are typically located within a single location, and the distance between the baseband circuit and the wireless circuit is relatively short, within a few meters. Unlike a conventional radio base station, a separate radio base station includes a remote equipment controller (REC) and a radio equipment (Remote End: RE). In a separate radio base station, the RE may be placed near the antenna, and the REC may be located at a connectable site. In other words, the separated wireless base station separates the RE that transmits and receives analog and wireless RF signals such as filtering, modulation, frequency conversion, and amplification through the antenna by RE, which performs digital baseband signal processing and wireless base station control and management, And the REC is placed at the central office station, so that efficient cell operation can be performed.

In this case, the REC and RE sections are connected with optical fibers and the like, and this section connected with the optical fiber is called a Common Public Radio Interface (CPRI). In the detachable wireless base station, data is transmitted and received between the REC and the RE through the CPRI.

The present invention provides a network and a signal transmission method for efficiently improving the capacity of a CPRI section by applying a wavelength division multiplexing (WDM) used in a wired optical network in a CPRI section.

The present invention provides a wired / wireless convergence network in which a wired optical network and a wireless network for a separate base station operation are fused.

 In one embodiment of the present invention, the wired network of the wired / wireless convergence network includes an optical line terminal (OLT) and an optical network unit (ONU), and the wireless network of the wired / wireless convergence network includes a public wireless interface (REC) and a wireless device (RE) that transmit and receive optical signals through a CPRI.

In the wireless network of the wired / wireless fused network according to the first embodiment of the present invention, the REC includes a reflective light source and a seed light source for injecting an upward signal having a fixed wavelength or a seed light for a down signal to the reflective light source , And the RE may include a reflective light source.

In a wireless network of a wire / wireless convergence network according to the second embodiment of the present invention, the RE may include a reflective light source.

In the wireless network of the wire / wireless convergence network according to the third embodiment of the present invention, the REC includes a reflective light source and a seed light source for injecting a seed light for downlink signal to the reflective light source, .

In a wireless network of a wire / wireless convergence network according to the fourth embodiment of the present invention, the REC and RE may include any one of a wavelength variable light source, at least one single mode laser, or a single mode laser array.

In a first embodiment of the present invention, a method of transmitting a signal includes the steps of: the REC transmitting a downstream signal having a fixed wavelength injected from a seed light source through a reflective light source to an RE; And transmitting the upstream signal having the fixed wavelength injected from the seed light source through the reflective light source to the REC.

In a second embodiment of the present invention, a signal transmission method includes the steps of the REC transmitting a downstream signal to a RE using at least one single mode laser; And the RE may reuse the downstream signal through the reflective light source and transmit the upstream signal to the REC.

In a third embodiment of the present invention, the signal transmission method includes the steps of: the REC transmits a downstream signal having a fixed wavelength injected from a seed light source through a reflective light source to an RE; And the RE may reuse the downstream signal through the reflective light source and transmit the upstream signal to the REC.

According to a fourth aspect of the present invention, there is provided a signal transmission method, wherein the signal transmission method comprises: transmitting, by the REC, a downstream signal inputted through a wavelength variable light source or a single mode laser to an RE; And transmitting the upstream signal input by the RE through the tunable light source or the single mode laser to the REC.

According to an embodiment of the present invention, the capacity of the CPRI section can be efficiently improved by applying the wavelength multiplexing scheme used in the wired optical network in the CPRI period.

Figure 1 shows a network topology between RE and REC.
2 is a diagram illustrating a wire / wireless convergence network according to a first embodiment of the present invention.
3 is a diagram illustrating a wire / wireless convergence network according to a second embodiment of the present invention.
4 is a diagram illustrating a wire / wireless convergence network according to a third embodiment of the present invention.
FIG. 5 is a diagram illustrating a wire / wireless convergence network according to a fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 shows a network topology between RE and REC.

Figure 1 A shows one CPRI link between one REC and one RE. 1B shows a plurality of CPRI links between one REC and one RE.

In other words, A shows a CPRI link between one REC and one RE, and B shows a plurality of CPRI links between one REC and RE. Also, FIG. 1C shows a star topology. That is, a plurality of REs can be connected to one REC.

According to one embodiment of the present invention, the network topology consisting of REC and RE is unlimited. For example, the network topology can be configured as star, ring, or bus type, and there can be one or more CPRI links between REC and RE.

Particularly, the present invention can be applied to a wavelength division multiplexing (WDM) used in a wired optical network in a CPRI link. In this case, the wavelength division multiplexing method may be any one of Coarse Wavelength Division Multiplexing (CWDM) and Dense Wavelength Division Multiplexing (DWDM).

In the present invention, the downstream signal means a signal from REC to RE or a signal from OLT to ONU, and the upstream signal means a signal from RE to REC or a signal from ONU to OLT.

Hereinafter, an example of a wire / wireless convergence network according to an embodiment of the present invention will be described. Here, the wired / wireless convergence network means a form in which a wired network and a wireless network are merged. The wired network includes an optical line terminal (OLT) and an optical network unit (ONU), and the wireless network includes a radio equipment controller (REC) and a radio equipment (RE) that transmit and receive optical signals through a public air interface (CPRI) do. In particular, the wireless network includes a wireless equipment controller (REC) and a wireless equipment (RE) that transmit and receive optical signals through a public air interface (CPRI) according to a wavelength division multiplexing scheme.

2 is a diagram illustrating a wire / wireless convergence network according to a first embodiment of the present invention.

Referring to FIG. 2, the REC and RE constituting the wireless network include a reflective light source and a seed light source for injecting an upward signal having a fixed wavelength or a seed light for a down signal to the reflective light source. Here, the reflective type light source includes a reflective semiconductor optical amplifier (RSOA), a Fabry-Perot Laser Diode (FP-LD), a reflective electro- (REAM) or a reflective amplifier (REAM) or a reflective optical modulator (RAM) in which a reflective optical modulator and a semiconductor optical amplifier are integrated.

The seed light source is located at the central station and is injected outside the reflective light source to determine the wavelength of the upstream signal or the downstream signal. Such a seed light source may be either a broadband light source or a single mode laser array. Here, the single mode laser array means that a plurality of single mode lasers are configured in an array form. The single mode laser may be a distributed feedback laser (DFB) laser, a distributed Bragg reflector laser (DBR), or a vertical-cavity surface-emitting laser (VCSEL).

3 is a diagram illustrating a wire / wireless convergence network according to a second embodiment of the present invention.

FIG. 3 can include a reflective light source only in the RE for cost efficiency as compared to FIG. The REC can send a downstream signal to the RE using a single mode laser array or a separate single mode laser. Then, RE can transmit an upstream signal to the REC by recycling the downstream signal as a seed light source.

4 is a diagram illustrating a wire / wireless convergence network according to a third embodiment of the present invention.

4 shows that the light source for the down signal and the light source for the up signal are composed of the reflection light source. That is, the seed light source is utilized for the downward signal in FIG. 4 as compared with FIG. The seed light source may be a broadband light source, and multiple single mode lasers or single mode laser arrays may be used. If multiple single mode lasers or single mode lasers are used, processing may be included to improve the reflection sensitivity of the link. The RE can recycle the downstream signal and send the upstream signal to the REC.

FIG. 5 is a diagram illustrating a wire / wireless convergence network according to a fourth embodiment of the present invention.

FIG. 5 shows a transmission of a signal using a wavelength tunable light source, a single mode laser array, or a separate single mode laser capable of wavelength tuning without using a reflective light source. That is, a wavelength variable light source, a single mode laser array, or a separate single mode laser can be utilized as a light source for transmitting a downstream signal or an upstream signal.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

201: OLT, REC
202: ONU
203: RE

Claims (20)

In a wired / wireless convergence network in which a wired network and a wireless network are fused,
The wired network includes an optical line terminal (OLT) and an optical network unit (ONU)
The wireless network includes a wireless equipment controller (REC) and a wireless equipment (RE) for transmitting and receiving optical signals through a public wireless interface (CPRI) according to a WDM scheme,
In the REC,
Generates a downlink signal using a seed light source that exists in the central office where the REC is located and determines a wavelength of a downlink signal transmitted from the REC to the RE and an uplink signal transmitted from the RE to the REC, To the RE,
The RE,
Wherein the downstream signal transmitted by the REC is reused to generate an upstream signal having a wavelength of the upstream signal determined by the seed light source. The method according to claim 1,
In the WDM scheme,
Wherein the optical fiber is one of a Coarse Wavelength Division Multiplexing (CWDM) or a Dense Wavelength Division Multiplexing (DWDM). The method according to claim 1,
The REC and RE are connected by at least one CPRI link,
Wherein the CPRI link is comprised of any one of star, ring and bus topologies. In a wired / wireless convergence network in which a wired network and a wireless network are fused,
Wherein the wired network comprises an optical line terminal (OLT) and an optical network unit (ONU), the wireless network comprising a radio equipment controller (REC) for transmitting and receiving optical signals and a radio equipment (RE)
The REC and the RE transmit signals through a public wireless interface (CPRI) according to a WDM scheme,
In the REC,
Generates a downlink signal using a seed light source that exists in the central office where the REC is located and determines a wavelength of a downlink signal transmitted from the REC to the RE and an uplink signal transmitted from the RE to the REC, To the RE,
The RE,
Wherein the downstream signal transmitted by the REC is reused to generate an upstream signal having a wavelength of the upstream signal determined by the seed light source. 5. The method of claim 4,
The seed light source includes:
A reflection type light source, and a seed light source for injecting an upstream signal having a fixed wavelength or a seed light for a downstream signal into the reflection type light source,
The RE,
Wherein the downstream signal is recycled using a reflection type light source. 6. The method of claim 5,
Wherein the upstream signal is processed so as to reduce the reflection sensitivity of the link. 5. The method of claim 4,
The seed light source includes:
A single-mode laser array or an individual single-mode laser. 5. The method of claim 4,
The REC includes the seed light source, the seed light source injects a seed light for a downstream signal into the reflection light source and the reflection light source,
Wherein the RE includes a reflective light source. 5. The method of claim 4,
The RECs and REs,
A wavelength tunable light source capable of tunable wavelength, at least one single mode laser or a single mode laser array. 9. The method according to any one of claims 4 to 8,
The seed light source includes:
Wherein the optical fiber is one of a broadband light source, a plurality of single mode lasers, or a single mode laser array. The method according to any one of claims 5 to 6 and 8,
The reflection-
Characterized in that it is any one of a reflection type semiconductor optical amplifier (RSOA), a Fabry-Perot laser diode (FP-LD), a reflection type external modulator, and a reflection type external modulator and a reflection type semiconductor optical amplifier. . 1. A signal transmission method for transmitting an optical signal through a wired / wireless convergence network in which a wired network and a wireless network are fused,
The wireless network includes a wireless equipment controller (REC) for transmitting and receiving optical signals and a wireless equipment (RE)
The signal transmission method includes:
The REC transmitting a downlink signal to the RE; And
The RE sending an uplink signal to the REC
Lt; / RTI >
The step of the REC transmitting the downlink signal to the RE comprises:
Generates a downlink signal by using a seed light source that exists in the central office where the REC is located and determines the wavelength of the downlink signal and the wavelength of the uplink signal,
The step of the RE transmitting the uplink signal to the REC comprises:
And generating the uplink signal from the downlink signal by utilizing the generated downlink signal as the seed light source. 13. The method of claim 12,
The step of the REC transmitting the downlink signal to the RE comprises:
The REC transmits a downstream signal having a fixed wavelength injected from the seed light source through the reflection light source to the RE,
The step of the RE transmitting the uplink signal to the REC comprises:
Wherein the RE transmits an upstream signal having a fixed wavelength injected from the seed light source through the reflection type light source to the REC. 14. The method of claim 13,
Wherein the seed lightwave for the upstream signal injected from the seed lightwave is processed so as to reduce the reflection sensitivity of the link. 13. The method of claim 12,
The step of the REC transmitting the downlink signal to the RE comprises:
The REC transmits a downstream signal to the RE using at least one single mode laser or a single mode laser array,
The step of the RE transmitting the uplink signal to the REC comprises:
Wherein the RE reuses the downstream signal through the reflective light source and transmits the upstream signal to the REC. 13. The method of claim 12,
The step of the REC transmitting the downlink signal to the RE comprises:
The REC transmits a downstream signal having a fixed wavelength injected from the seed light source through the reflection light source to the RE,
The step of the RE transmitting the uplink signal to the REC comprises:
Wherein the RE reuses the downstream signal through the reflective light source and transmits the upstream signal to the REC. 13. The method of claim 12,
The step of the REC transmitting the downlink signal to the RE comprises:
The REC transmits a downstream signal inputted through a wavelength variable light source, a single mode laser or a single mode laser array to the RE,
The step of the RE transmitting the uplink signal to the REC comprises:
Wherein the RE transmits an upstream signal inputted through a wavelength variable light source, a single mode laser or a single mode laser array to a REC. 18. The method according to any one of claims 13 to 17,
The REC and the RE are,
Wherein the optical signal is transmitted / received based on any one of Coarse Wavelength Division Multiplexing (CWDM) or Dense Wavelength Division Multiplexing (DWDM). 18. The method according to any one of claims 13 to 17,
The REC and RE are connected by at least one CPRI link,
Wherein the CPRI link is configured in one of a star, ring, or bus topology. 17. The method according to any one of claims 13 to 16,
The reflection-
A signal transmission method characterized by being a reflection type semiconductor optical amplifier (RSOA), a Fabry-Perot laser diode (FP-LD), a reflection type external modulator, and an integrated device in which a reflection type external optical modulator and a reflection type semiconductor optical amplifier are integrated .

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