KR101190339B1 - Apparatus and method for hybrid transmission of combining passive optical network and hybrid fiber coaxial network for data and broadcasting service - Google Patents

Abstract

The present invention relates to an apparatus and method for hybrid broadcasting and communication transmission combining a passive optical communication network and an optical coaxial hybrid network, receiving content from the passive optical communication network, separating broadcast signals and data signals from the received content, and The separated signal may be processed as a radio frequency (RF) signal of different bands, and the combined signals may be controlled to be transmitted to the subscriber station through one coaxial line.

Description

Hybrid broadcasting and communication transmission device and method combining passive optical network and optical coaxial hybrid network

The present invention relates to a hybrid broadcasting and communication transmission apparatus and method combining a passive optical communication network and an optical coaxial hybrid network, and a data (communication) service and a broadcasting service by combining a passive optical network (PON) and a hybrid fiber coaxial (HFC) network. It relates to a technology for providing.

Hybrid Fiber & Coaxial (HFC) is a communication technology in which fiber and coaxial cables are used in different parts of the network to transport broadband content such as video, data and voice.

1 is a diagram illustrating an HFC network 100 to which an HFC is applied.

Local cable television (TeleVision) companies provide broadcast content through systems 101 and 102, using fiber optic cables from cable headends to nodes (ONU, 103) in close proximity to users in businesses or homes. Coaxial cable is used for individual companies and household subscribers.

The advantage of HFC is that some of the characteristics of fiber-optic cable can be carried closer to the user without having to replace the existing coaxial cable that is always installed in the enterprise or home.

Therefore, the HFC network 100 uses the optical cable from the distribution center to the ONU 103, and the coaxial cable from the ONU 103 to the subscriber, a large amount of data, for example, the Internet, cable TV, security, disaster prevention, remote It is a broadband transmission network that can transmit meter reading and automatic control.

The ONU 103 has an optical transceiver as the center of the cell so that the downlink signal transmitted from the distribution center to the optical cable is converted from the optical signal to the electrical signal, and the upstream signal is converted from the electrical signal to the optical signal.

Trunk Distribution Amplifier (TDA) for compensating line signal loss and splitter and subscriber for distributing one signal into two or more equal power signals on transmission line connecting ONU 103 and subscriber It consists of a tap-off, which is the last element of the transmission network for equally distributing signals to the terminals.

Currently, the uplink data transmission band (subscriber end distribution center) available for the HFC network 100 is 5-42 MHz, and the downlink broadcasting band (the subscriber end of the broadcasting station) is 54-550 MHz, and the data transmission and digital broadcasting service is 550- The downlink frequency band of 870MHz is used. The maximum downlink frequency is expanding from 870MHz to 2.6GHz band, the maximum uplink frequency is expanding from 42MHz to 65MHz, and finally the maximum uplink frequency is 85MHz.

The HFC system includes a broadcasting system 101 for transmitting analog and digital broadcasts located at the headend, a cable modem termination system (CMTS) 102 for transmitting data located at the headend, an optical fiber in a distribution network area, a coaxial cable, A photoelectric converter, a cable modem 104 in the subscriber area, or a cable modem built-in STB (Set-Top Box).

The broadcast system transmits a broadcast signal downward, and the CMTS and the cable modem use an out-of-band (OOB) method or a standardized data over cable service interface specifications (DOCSIS) method for exchanging bidirectional data.

For reference, the out-of-band channel method is a standard that defines the transmission standard between the broadcaster's transmission system (headend) and the STB, and the DOCSIS method is a transmission method between the CMTS of the headend and the DOCSIS-based cable modem in the STB. Standard adopted by Cable Labs, a broadcasting standards certification body.

In recent years, in addition to the HFC network 100, a passive optical network (PON) is used.

2 illustrates the PON 200.

The PON 200 is an endpoint equipment of a service provider in the PON. The PON 200 distributes the optical signals in the same size to the OLT (201, Optical Line Terminal) that is responsible for photoelectric conversion between the electrical signals of the service provider apparatus and the optical signals used in the PON. The splitter 202, which is a passive device, and an ONT (203, 204 Optical Network Terminal) classified as optical end equipment in the PON.

PON is composed of a point-to-multipoint (1: N) method in which a single fiber is branched into several strands of fiber through a passive optical splitter, and subscribers are connected to each branched fiber. The PON may be composed of an OLT 201 installed in a national office, an optical distribution network (ODN), an ONT 203, 204, or an optical network unit (ONU) installed in a subscriber's home or outdoor environment.

The PON system utilizes the infinite bandwidth and high reliability of the fiber to support more than 1Gbps bandwidth. In the 1-N PON distribution network structure, the optical transceiver module can be reduced, and bandwidth can be shared through the PON. In addition, it is easy to expand to high-speed time division multiplexing (TDM) and wave length division multiplexing (WDM), and a communication and broadcast convergence service may be provided as a system that is most suitable for applying a video overlay scheme.

The hybrid transmission apparatus according to an embodiment of the present invention receives a content from a passive optical communication network, a wavelength division multiple optical signal separation / combining unit for separating a broadcast signal and a data signal from the received content, and the separated signal It may include a signal processor for processing a radio frequency (RF) signal of different bands, and RF signal separation / combining unit for controlling each of the processed signals to be transmitted to the subscriber station via one coaxial line.

In a hybrid transmission method according to an embodiment of the present invention, receiving content from a passive optical communication network, separating a broadcast signal and a data signal from the received content, and converting the separated signal into radio frequency (RF) of different bands. And a step of combining the processed signals and controlling each signal to be transmitted to a subscriber station through one coaxial line, wherein the processing of the separated signal comprises: Processing the broadcast signal and processing the data signal among the separated signals.

According to an embodiment of the present invention, it is possible to provide a more efficient broadcasting and communication transmission system by utilizing the advantages of the PON and the advantages of the HFC network.

According to an embodiment of the present invention, up to 63 coaxial communication modems may be connected to ONT, which is an end device of a PON network, thereby facilitating cell division and network expansion.

According to an embodiment of the present invention, since the broadcast signal and the data signal is transmitted from one head cable to a hybrid transmission device replacing the existing ONU, it is advantageous to CATV operators lacking an optical core and reduces the cost for laying the optical cable. You can expect the effect.

According to an embodiment of the present invention, using a coaxial cable modem rather than a DOCSIS-based modem utilizing a conventional HFC network, using a maximum 30MHz bandwidth in a low frequency band of 2-34MHz, TCP (up to 200Mbps or more in the physical layer) Control Protocol throughput can be provided.

1 is a diagram illustrating an HFC network to which HFC is applied.
2 is a diagram for explaining a PON.
3 is a diagram illustrating a broadcasting and communication system to which a hybrid transmission device according to an embodiment of the present invention is applied.
4 is a block diagram illustrating a hybrid transmission device according to an embodiment of the present invention.
5 is a flowchart illustrating a hybrid transmission method according to an embodiment of the present invention.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The terminologies used herein are terms used to properly represent preferred embodiments of the present invention, which may vary depending on the user, the intent of the operator, or the practice of the field to which the present invention belongs. Therefore, the definitions of the terms should be made based on the contents throughout the specification. Like reference symbols in the drawings denote like elements.

3 is a diagram illustrating a broadcast and communication system 300 to which the hybrid transmission device 304 according to an embodiment of the present invention is applied.

The broadcast and communication system 300 may receive content in which a broadcast signal and a data signal are combined through a passive optical network (PON).

An optical transmitter 301 of a passive optical network transmits a broadcast signal having a wavelength λ a, and an optical line terminal 302 (OLT, optical line terminal) has a data signal of a wavelength λ b (down channel) / λ c (up channel). Send the.

Broadcast signals and data signals of different wavelengths may be combined into content through a WDM (Wavelength Division Multiplexing) coupler and may be transmitted to multiple subscriber stations through one optical fiber.

In this case, the content may be delivered to the subscriber station through a hybrid fiber coaxial (HFC) network, the hybrid transmission device 304 may convert the content of the optical signal form of the PON to a radio frequency (RF) signal of the HFC network. have.

In detail, the hybrid transmission device 304 according to an embodiment of the present invention may receive content from a passive optical communication network and separate a broadcast signal and a data signal from the received content.

In addition, the hybrid transmission apparatus 304 according to an embodiment of the present invention converts the separated signal into a radio frequency (RF) signal of different bands, and combines the converted signals to form one coaxial line. Through the subscriber station (305, 306) can be transmitted.

The hybrid transmission equipment and the subscriber stations 305 and 306 are connected by a coaxial cable, and the subscriber station 305 for data communication may use a coaxial line communication (CLC) method.

The coaxial communication method uses bidirectional signal division using the Orthogonal Frequency Division Multiplexing (OFDM) modulation scheme in the HFC network using a coaxial line as a communication medium using a maximum bandwidth of 30 MHz in a low frequency band of 2-34 MHz. Communication method.

As a result, the broadcasting and communication system 300 to which the hybrid transmission apparatus 304 according to the embodiment of the present invention is applied may provide a more efficient broadcasting and communication transmission system by utilizing the advantages of PON and the advantages of HFC network.

For example, the broadcasting and communication system 300 to which the hybrid transmission device 304 is applied can connect up to 63 coaxial communication modems to ONT, which is an end device of the PON network, thereby facilitating cell division and network expansion. From the headend to the hybrid transmission equipment replacing the existing ONU, it transmits broadcast signal and data signal with one optical cable, which is advantageous for CATV operators lacking optical cores and can expect cost reduction effect for optical cable laying.

In addition, the broadcasting and communication system 300 to which the hybrid transmission device 304 is applied may provide a Transmission Control Protocol (TCP) throughput of up to 200 Mbps or more in the physical layer.

4 is a block diagram illustrating a hybrid transmission apparatus 400 according to an embodiment of the present invention.

The hybrid transmission apparatus 400 according to an embodiment of the present invention may include a wavelength division multiple optical signal splitter / combiner 410, a signal processor 420, and an RF signal splitter / combiner 430.

The wavelength division multiplex optical signal separating / combining unit 410 may receive content from a passive optical communication network and separate a broadcast signal and a data signal from the received content.

The signal processor 420 may convert the separated signal into RF (Radio Frequency) signals of different bands and process the separated signals.

To this end, the signal processor 420 may include a broadcast signal processor that processes the broadcast signal among the separated signals and a data signal processor that processes the data signal among the separated signals.

First, the broadcast signal processor may include an optical receiver 421 for photoelectric conversion of the separated broadcast signal into a high frequency electrical signal, and an RF signal amplifier for amplifying the photoelectrically converted broadcast signal. 422, Amplifier).

Specifically, the optical receiver 421 is connected to the broadcast signal output port of the wavelength division multiplex optical signal splitter / combiner 410, and the broadcast signal in the optical signal form may be photoelectrically converted through the optical receiver 421. . Accordingly, the RF signal amplifier 422 may amplify the photoelectrically converted broadcast signal to a predetermined size and convert the broadcast signal having a frequency f1.

Next, the data signal processor includes an optical network terminal (423) for photoelectric conversion of the separated data signal into a low frequency electrical signal, and a data signal converted into the low frequency electrical signal. It may include a coaxial line communication master card (424, 424) for modulating the RF signal.

In detail, the optical network terminal 423 may be connected to the data signal output port of the wavelength division multiplex optical signal separating / combining unit 410 to transmit and receive data signals.

The photoelectrically converted data signal in the optical network terminal 423 may be modulated by the coaxial master card 424 and converted into an RF signal.

The coaxial communication master card 424 according to an embodiment of the present invention may convert the photoelectrically converted data signal into an RF signal by modulating an orthogonal frequency division multiplexing (OFDM) method.

The RF signal separating / combining unit 430 may control to combine the processed signals and transmit the combined signals to a subscriber station through one coaxial line.

That is, data and broadcast signals converted into RF signals of different frequency bands are combined by the RF signal separation / combining unit 430 including the function of a diplexer and then transmitted to the subscriber end through the same coaxial line. Can be.

The RF signal separator / combiner 430 may include a passive element including a low pass filter (LPF) and a high pass filter (HPF).

The RF signal separation / combining unit 430 may output a component below a specific frequency band to a low pass filter and a component above a specific frequency band to a high pass filter with respect to a signal input through the same port.

5 is a flowchart illustrating a hybrid transmission method according to an embodiment of the present invention.

The hybrid transmission method according to an embodiment of the present invention may receive the content from the passive optical communication network (step 501) and separate the broadcast signal and the data signal from the received content (step 502).

The broadcast signal and the data signal are optical signals having different wavelengths and may be separated / combined using a coupler.

Next, in the hybrid transmission method according to an embodiment of the present invention, the separated signal may be converted into a radio frequency (RF) signal of different bands and processed (step 503).

In this case, the hybrid transmission method according to an embodiment of the present invention may process the broadcast signal from the separated signal, and may process the data signal from the separated signal in parallel.

For example, in the hybrid transmission method according to an embodiment of the present invention, in order to process the broadcast signal, the separated broadcast signal is photoelectrically converted into a high frequency electrical signal and the photoelectrically converted broadcast signal. May be amplified and processed into a first RF signal having a frequency f1.

In addition, the hybrid transmission method according to an embodiment of the present invention, in order to process the data signal, photoelectric conversion of the separated data signal into a low frequency (low frequency) electrical signal, and converting the photoelectrically converted data signal to RF The signal may be modulated into a second RF signal having a frequency f 2.

The converted first RF signal and the second RF signal may be transmitted to the subscriber station through the same coaxial line.

That is, the hybrid transmission method according to an embodiment of the present invention may control to combine each of the processed signals and transmit them to a subscriber station through one coaxial line (step 504).

Specifically, in the hybrid transmission method according to an embodiment of the present invention, in order to control to transmit each of the processed signals to a subscriber station, a high-band broadcast signal (first RF signal) of each of the processed signals is transmitted. A high pass filter may be output, and the low band data signal (second RF signal) may be output to a subscriber station through a low pass filter.

As a result, by using the hybrid transmission method according to an embodiment of the present invention, it is possible to provide a more efficient broadcasting and communication transmission system by utilizing the advantages of the PON and the advantages of the HFC network.

Specifically, by using the hybrid transmission method according to an embodiment of the present invention, up to 63 coaxial communication modems may be connected to ONT, which is an end device of the PON network, thereby facilitating cell division and network expansion.

In addition, since it transmits broadcast signal and data signal from one head cable to hybrid transmission equipment replacing the existing ONU, it is advantageous to CATV operators lacking optical core and can expect cost-saving effect on the installation of optical cable. By utilizing the existing HFC network, it is possible to provide transmission control protocol (TCP) throughput of up to 200Mbps or more in the physical layer in that it uses a coaxial communication modem rather than a DOCSIS-based modem.

Hybrid transmission method according to an embodiment of the present invention is implemented in the form of program instructions that can be executed by various computer means may be recorded on a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic disks, such as floppy disks. Magneto-optical media, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. 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.

400: hybrid transmission device 410: wavelength division multiple optical signal separation / combination unit
420: signal processor 421: optical receiver
422: RF signal amplifier 423: optical network terminal
424: coaxial master card 430: RF signal separation / coupling section

Claims (13)

A wavelength division multiple optical signal separating / combining unit for receiving contents from a passive optical communication network and separating broadcast signals and data signals from the received contents;
A signal processor which modulates the separated signal by an Orthogonal Frequency Division Multiplexing (OFDM) scheme and processes the separated signal into RF signals of different bands; And
RF signal separation / combining unit which combines the processed signals and transmits them to a subscriber station through one coaxial line
Including,
The RF signal separation / combining unit transmits the combined signals to the subscriber station through a single coaxial line using a maximum 30 MHz bandwidth in a low frequency band of 2-34 MHz. The method of claim 1,
The received content includes the broadcast signal and the data signal in the form of optical signals having different wavelengths, and the wavelength division multiplex signal separating / combining unit receives the content from the passive optical network through the same optical fiber. Hybrid transmission device. The method of claim 1,
The signal processing unit,
A broadcast signal processor configured to process the broadcast signal among the separated signals
Hybrid transmission device comprising a. The method of claim 3,
The broadcast signal processor,
An optical reception unit for photoelectric conversion of the separated broadcast signal into a high frequency electrical signal;
RF signal amplifier for amplifying the photoelectric conversion broadcast signal
Hybrid transmission device comprising a. The method of claim 1,
The signal processing unit,
A data signal processor configured to process the data signal among the separated signals
Hybrid transmission device comprising a. The method of claim 5,
An optical network terminal for photoelectric conversion of the separated data signal into a low frequency electrical signal;
Coaxial communication master card for modulating the data signal converted into the electrical signal of the low band to the RF signal
Hybrid transmission device comprising a. delete The method of claim 1,
The RF signal separation / coupling unit,
A high pass filter for outputting a high band broadcast signal; And
Low pass filter to output low band data signal
Hybrid transmission device comprising a. Receiving content from a passive optical communication network, and separating a broadcast signal and a data signal from the received content;
Modulating the separated signal by an orthogonal frequency division multiplexing (OFDM) method and processing the separated signal into radio frequency (RF) signals of different bands; And
Combining each of the processed signals and controlling each of the combined signals to be transmitted to a subscriber station through one coaxial line using a maximum 30 MHz bandwidth in a low frequency band of 2-34 MHz;
Including,
Processing the separated signal,
Processing the broadcast signal among the separated signals; And
Processing the data signal among the separated signals
Hybrid transmission method comprising a. 10. The method of claim 9,
The processing of the broadcast signal among the separated signals may include:
Photoelectric conversion of the separated broadcast signal into a high frequency electrical signal and amplifying the photoelectrically converted broadcast signal. 10. The method of claim 9,
The processing of the data signal among the separated signals may include:
Photoelectric conversion of the separated data signal into a low frequency electrical signal, and modulating the photoelectrically converted data signal into an RF signal. 10. The method of claim 9,
The step of controlling to transmit each of the processed signal to the subscriber terminal,
Outputting a high band broadcast signal from each of the processed signals through a high pass filter and outputting a low band data signal from each of the processed signals to a subscriber station through a low pass filter; Hybrid transmission method. A computer-readable recording medium having recorded thereon a program for performing the method of any one of claims 9 and 12.

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