KR100642851B1 - Optical network unit and optical transmitting network included the unit - Google Patents

Abstract

The present invention relates to an optical transmission network capable of performing data transmission services of different bands through one transmission medium and an optical termination device (ONU) used therein, the optical transmission network comprising: a;

A headend for converting a broadcast signal into a downlink optical signal, transmitting the downlink optical signal to an optical communication line, and separating and processing the uplink data communication optical signal applied through the optical communication line into a data communication signal for each wavelength;

At least one branch element for branching the downlink optical signal transmitted from the headend into a plurality of channels and combining the uplink optical signals transmitted from the plurality of divided channels to transmit the downlink optical signal to an optical communication line through which the downlink optical signal is transmitted;

An optical branching element for branching a downlink optical signal transmitted from a corresponding branching element among the branching elements into different channels and transmitting an uplink data communication optical signal transmitted from one of the branched channels to the corresponding branching element; However, at least one optical termination device for generating and outputting optical signals for data communication of different wavelengths; characterized in that it comprises a.

Broadcast signal, headend, up / down optical communication line.

Description

OPTICAL NETWORK UNIT AND OPTICAL TRANSMITTING NETWORK INCLUDED THE UNIT}

1 is a block diagram of a general optical transmission network for servicing wideband data and narrowband data.

FIG. 2 is a block diagram illustrating an optical network unit (ONU) and an optical transmission network including the same according to an embodiment of the present invention.

The present invention relates to an optical transmission network structure, and more particularly, to an optical transmission network capable of transmitting a wideband data and narrowband data through one transmission medium.

With the development of optical communication technology, fiber optics have been introduced into wired networks. The introduction of optical fiber in wired networks is an inevitable result of overcoming the physical limitations (limited bandwidth and large losses) of existing communication networks that have been dependent on twisted pairs and coaxial cables.

 In particular, as the price of optical communication-related devices and equipment is falling and the optical communication system becomes economical, many researches and developments are being made on optical transmission networks using optical fibers. The structure of such an optical transmission network is shown in FIG.

FIG. 1 illustrates a general optical transmission network configuration for serving wideband data and narrowband data. The exemplary optical transmission network includes a headend 10 serving as a central base station and a remote node. Corresponding distributors 20 and 30 and optical terminators (ONU) 40.

The wideband data refers to service data such as video on demand and cable broadcasting signal (CATV), and the narrowband data refers to communication data required for telephone and internet communication.

Referring to FIG. 1, the head end 10 includes a CATV optical transmitter (also called LD) 12 and a light receiver 14 for transmitting CATV signals to each subscriber. The CATV optical signal generated by the CATV optical transmitter 12 is transmitted to the distributor 20 through the optical communication line constituting the downlink channel, and the CATV optical signal transmitted to the distributor 20 is branched again to provide a plurality of ONUs. Respectively sent to 40.

The ONU 40, which is an optical termination device, connects an optical communication network and a copper wire network to convert a signal of an optical communication network to fit a copper wire network or to convert a signal of a copper wire network to a optical communication network. The ONU 40 includes an optical receiver 42 for receiving an optical signal for CATV, a demodulator for demodulating narrowband service request data transmitted through a cable modem, and a narrowband demodulated by the demodulator. And an optical transmitter 44 for data communication for transmitting the service request data as an optical signal.

The optical signal generated by the optical communication unit 44 for data communication is transmitted to the optical communication unit 14 for data communication of the headend 10 through the splitter 30 and the optical communication line of the upstream channel, thereby narrowband transmitted from each subscriber. The service request data of the headend 10 is transmitted to another place through the service network.

In the optical transmission network as described above, since the wideband data and narrowband data are transmitted between the headend 10 and the ONU 40 through separate transmission media, when the number of optical subscribers increases, the uplink and downlink optical communication is performed accordingly. Each track must be extended.

However, it is inefficient to expand the optical telecommunication lines indefinitely in accordance with the increase in the number of optical subscribers. Therefore, a new model network structure is required that can accommodate the optical subscribers only by the existing optical telecommunication lines without additional optical telecommunication lines.

Accordingly, an object of the present invention is to provide an optical transmission network that enables transmission service of broadband data and narrowband data through one transmission medium.

Furthermore, another object of the present invention is to provide a new model of optical transmission network capable of maximally accommodating optical subscribers using only existing optical communication lines without additional optical communication lines.

An optical transmission network according to an embodiment of the present invention for achieving the above object,

A headend for converting a broadcast signal into a downlink optical signal, transmitting the downlink optical signal to an optical communication line, and separating and processing the uplink data communication optical signal applied through the optical communication line into a data communication signal for each wavelength;

At least one branch element for branching the downlink optical signal transmitted from the headend into a plurality of channels and combining the uplink optical signals transmitted from the plurality of divided channels to transmit the downlink optical signal to an optical communication line through which the downlink optical signal is transmitted;

An optical branching element for branching a downlink optical signal transmitted from a corresponding branching element among the branching elements into different channels and transmitting an uplink data communication optical signal transmitted from one of the branched channels to the corresponding branching element; However, at least one optical termination device for generating and outputting optical signals for data communication of different wavelengths; characterized in that it comprises a.

Furthermore, the headend of the optical transmission network according to the embodiment of the present invention,

An optical transmitter for converting the broadcast signal into a downlink optical signal;

A headend branching element for transmitting a downlink optical signal generated by the optical transmitter to the optical communication line and for branching uplink optical signals applied through the optical communication line;

And a demultiplexer for demultiplexing the uplink data communication optical signals transmitted through the headend branch element for each wavelength and transmitting the wavelengths to the optical receiver for each wavelength.

It is characterized by using any one of an optical coupler or an optical circulator as the branch end for the head end.

Also, the optical transmission network according to another embodiment of the present invention converts a downlink optical signal for CATV into an electrical signal and outputs it to an image output device, and generates and outputs an uplink optical signal for data communication (ONU) ), And branching elements for multiplexing uplink optical signals transmitted from the optical terminators and transmitting them to the headend through a line different from an optical communication line through which the downlink optical signals are transmitted.

The headend,

An optical transmitter for converting the broadcast signal into a downlink optical signal;

A headend branch element for transmitting a downlink optical signal generated by the optical transmitter to a downlink optical communication line and for branching uplink data signals applied through an uplink optical communication line;

And a WDM demultiplexer for demultiplexing the uplink data communication optical signals transmitted through the headend branch element for each wavelength and transmitting the wavelengths to the optical receiver for each wavelength.

On the other hand, the optical terminal (ONU) according to an embodiment of the present invention,

An optical receiver for receiving a downlink optical signal transmitted through an optical communication line and converting the optical signal into an electrical signal; Basically includes an optical transmitter for generating an upward optical signal,

And an optical branching element which transmits the downlink optical signal transmitted from the optical communication line to the optical receiving unit and transmits the uplink optical signal generated from the optical transmission unit to the optical communication line.

According to the characteristics of the present invention as described above, since up and down data can be transmitted and received through a single optical communication line connecting the headend and the branch element, separate transmission of the up and down data through a separate optical communication line Compared to the conventional optical transmission network will have the advantage of increasing the efficiency of using the optical communication line.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

First, FIG. 2 illustrates the configuration of an optical network unit (ONU) 400 and an optical transmission network including the same according to an embodiment of the present invention.

Referring to FIG. 2, first, an optical transmission network according to an embodiment of the present invention includes a branch element 300 connected through one head end 100 and an optical communication line 200, and one branch element 300. It includes a plurality of optical termination device 400 is connected via an optical communication line. The number of the optical terminator 400 and the branch element 300 has a variable value in accordance with the optical subscriber capacity.

The headend 100 serves as a central base station to distribute a broadband service signal or a narrowband service signal to each optical subscriber and to transmit a signal transmitted from each subscriber to another place.

More specifically, the headend 100 converts a broadcast signal such as CATV (corresponding to a broadband service signal) into a downlink optical signal and transmits the downlink optical signal to the optical communication line 200, and the upward data applied through the optical communication line 200. Optical signals for communication (corresponding to narrowband service signals) are separated into wavelength-specific data communication signals (lambda _1, lambda _2, ..., lambda _n) and processed. To this end, the head end 100,

An optical transmitter 110 for converting the broadcast signal into a downlink optical signal and a downlink optical signal generated by the optical transmitter 110 are transmitted to the optical communication line 200 and applied through the optical communication line 200. And a headend branch element 130 for branching uplink optical signals. Any one of an optical coupler or an optical circulator may be used as the headend branch element 130.

In addition, the headend 100 demultiplexes the uplink data communication optical signals transmitted through the headend branch element 130 by wavelength (lambda _1, lambda _2,..., Lambda _n) for each wavelength. The apparatus further includes a WDM demultiplexer 120 for transmitting to a separate optical receiver for data communication. In addition to the configurations listed above, the headend 100 is basically connected to other service networks and basically includes technical configurations provided by the general headend. Since these configurations are already known, a detailed description thereof will be omitted.

Meanwhile, the branch element 300 connected to the head end 100 through a designated optical communication line 200 branches the downlink optical signal transmitted from the head end 100 into a plurality of channels, and is transmitted from the branched multiple channels. By combining the optical signals for the uplink data communication transmits the downlink optical signal to the optical communication line 200 is transmitted. As the branch element 300, a splitter of 1 × N can be used. The nature of this splitter acts as an optical power splitter for downlink signals and acts as an optical wavelength divider for upstream signals of different wavelengths.

The optical termination unit (ONU) 400 respectively connected to the optical communication lines branched into the plurality of channels in the branch element 300 includes an optical communication unit 430 for generating data communication optical signals having different wavelengths. do. In addition, each optical terminator 400 includes a CATV optical receiver 420 for receiving and converting the downlink optical signal transmitted through the optical communication line into an electrical signal,

The downlink optical signal transmitted from the branch element 300 is divided into different channels and transmitted to the CATV optical receiver 420, and the uplink optical signal for data communication transmitted from the data communication optical transmitter 430 is It further includes an optical branching element 410 to transmit to the branching element (300). As the optical splitter 410, any one of an optical coupler and an optical circulator may be used. In the case of using the optical circulator, since the optical signal transmitted from the branch element 300 can be transmitted only to the CATV optical receiver 420, the optical circuit has an additional advantage of protecting the data communication optical transmitter 430.

On the other hand, the optical termination unit (ONU) 400 has a structure that is connected to the set-top box (STB) and the cable modem in the home through the existing copper wire network, the optical signal transmitted through the optical communication line set-top box or cable modem The present invention further includes a technical configuration required to transmit an electrical signal for data communication transmitted from the cable modem or from the cable modem to the optical communication line, for example, a data modulation / demodulator, a microprocessor for controlling the wavelength intensity of the optical signal. This configuration is also a configuration of a general optical termination unit (ONU), so a detailed description thereof will be omitted.

Hereinafter, a process in which an uplink optical signal and a downlink optical signal are transmitted through the same optical communication line 200 in the optical transmission network having the above-described configuration will be described.

First, the CATV broadcast signal provided by the program provider is modulated by the head end 100 and then converted into a downlink optical signal having a predetermined wavelength through the CATV optical transmitter 110. As described above, the downlink optical signal generated by the CATV optical transmitter 110 is transmitted to the optical communication line 200 through the optical coupler 130 and transmitted to the splitter 300 which is a branch element. Then, the splitter 300 separately outputs downlink optical signals transmitted through the optical communication line 300 to n channels, such that the plurality of optical terminators 400 connected to the splitter 300 through the optical communication line are downward. The optical signal is transmitted, and the optical coupler 410 located at the signal input end of each optical terminator 400 outputs the downlink optical signal to the CATV optical receiver 420 and the data communication optical transmitter 430. do.

Accordingly, the CATV optical receiver 420 converts the downlink optical signal transmitted through the optical coupler 410 into an electrical signal and outputs the electrical signal. As described above, the CATV broadcast signal converted into an electrical signal through the optical receiver 420 is processed and transmitted to a signal required for transmission to the indoor set-top box (STB), so that the indoor optical subscriber uses the set-top box (STB). You will be able to watch cable TV.

Meanwhile, the electrical signal for data communication transmitted to the optical terminator 400 through the cable modem mounted in the indoor information terminal (PC) is demodulated by the optical terminator 400 and then the optical signal for data communication in the optical communication unit 430 for data communication. Is converted to output. The laser power of the light source required to generate the optical signal for data communication should be set differently for each optical terminator 400.

The data communication optical signal generated by the data communication optical transmitter 430 is transmitted to the splitter 300 which is a branch element through the optical coupler 410, so that the splitter 300 is generated from each optical terminator 400. The optical signals of different wavelengths are multiplexed and transmitted to the head end 100 through the uplink optical communication line 200. The uplink optical communication line 200 represents the same line as the downlink optical communication line 200 mentioned above.

Meanwhile, the uplink data signal transmitted to the headend 100 is branched to the CATV optical transmitter 110 and the WDM DEMUX 120 through the optical coupler 130 on the headend 100. Then, the WDM DEMUX 120 demultiplexes the transmitted optical communication signal for each wavelength and transmits the data signal to the optical communication unit for data communication. The optical communication unit for data communication converts the optical signal for data communication into an electric signal to other service networks. To pass.

In conclusion, in the present invention, since the service signal of the wide band, such as CATV, as well as the narrow band data communication signal are transmitted and received as different wavelengths through the same optical communication line, the optical communication line between the headend 100 and the branch element 300. Will be able to save.

As described above, since the present invention enables transmission and reception of up and down data through a single optical communication line connecting a headend and a branch element, the conventional method of separately transmitting up and down data through a separate optical communication line Compared to the optical transmission network of the optical communication line will have the advantage of increasing the efficiency of use.

On the other hand, the present invention has been described with reference to the embodiments shown in the drawings, which are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be defined only by the appended claims.

Claims (7)

delete An optical transmitter for converting a broadcast signal into a downlink optical signal, and transmitting a downlink optical signal generated by the optical transmitter to an optical communication line and branching uplink data signals applied through the optical communication line to an optical receiver for data communication A headend including a headend branching element for receiving a headend, and a WDM demultiplexer for demultiplexing uplink data communication optical signals transmitted through the headend branching element for each wavelength and transmitting the demultiplexer to a data communication optical receiving unit; ; A branching element for branching the downlink optical signal transmitted from the headend into a plurality of channels, combining uplink optical signals transmitted from the plurality of divided channels, and transmitting the downlink optical signal to the optical communication line to which the downlink optical signal is transmitted; An optical branching element for branching the downlink optical signal transmitted from the branching element into different channels, a light receiving unit for a broadcast signal for converting the downlink optical signal transmitted from the optical branching element into an electrical broadcast signal, and a different And an optical termination device including an optical transmission unit for generating a data communication optical signal having a wavelength and transmitting the optical signal to the optical branch element. The optical transmission network according to claim 2, wherein the head end branch element, the branch element, and the optical branch element are any one of an optical coupler or an optical circulator. delete delete delete delete

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