KR100576730B1 - Optical line terminal and Optical network terminal for servicing hybrid data in PON - Google Patents

Abstract

The present invention relates to an OLT and ONT for providing a converged service of a broadcast data service and a communication data service in a passive optical network. In particular, the present invention relates to multiplexing of multichannel broadcasting such as cable TV broadcasting or satellite broadcasting. The present invention relates to an OLT and ONT for accommodating a broadcast service and a data communication service to provide a converged service in which broadcasting and communication are converged.

In the passive optical network disclosed in the present invention, the OLT for providing a convergence service of a broadcast data service and a communication data service includes a broadcast data transmitter for converting broadcast data of an RF signal into a broadcast optical signal and transmitting the broadcast data to a subscriber; A communication data transmitter for converting communication data of an electrical signal into an optical signal for communication and transmitting the same to a subscriber; And a multiplexer for fusing the communication optical signal and the broadcast optical signal and multiplexing them into a single optical signal of multiple wavelengths in order to transmit the two optical signals to the subscriber side via a PON in a single light beam. Achieve the task

Description

Optical line terminal and optical network terminal for servicing hybrid data in PON for providing convergence service of broadcasting data service and communication data service in passive optical network

1 is a diagram illustrating a configuration of a cable TV network using HFC, which is one of several methods for providing a converged service.

FIG. 2 is a diagram illustrating a delivery network for implementing VOD broadcasting and Internet broadcasting service, which are other forms of broadcasting services currently provided.

3 is a diagram illustrating a configuration of an OLT for a broadcast service using an existing EPON network.

4A is a diagram illustrating a network structure and a system structure capable of providing a broadcast service using a PON network according to the present invention.

FIG. 4B is a diagram illustrating a configuration of a preferred embodiment of the broadcast data transmitter shown in FIG. 4A.

4C is a diagram illustrating still another configuration of the preferred embodiment of the broadcast data transmission unit shown in FIG. 4A.

FIG. 4D is a diagram showing the configuration of a preferred embodiment of the ONT shown in FIG. 4A.

The present invention relates to an OLT and ONT for providing a converged service of a broadcast data service and a communication data service in a passive optical network. In particular, the present invention relates to a multi-channel broadcast such as cable TV broadcast or satellite broadcast, using a single-line communication network. The present invention relates to an OLT and ONT that provide a converged service in which broadcasting and communication are converged by receiving a broadcasting service and a data communication service.

Currently, for home subscribers, Internet service and VOD broadcasting service (communication service) are delivered to PC through ISP (Internet Service Provider), and broadcasting service is directly received through terrestrial wave, cable TV network or satellite. It is being serviced through TV through various media such as satellite broadcasting.

However, since there exists a broadcast service using such various media, in order for the same subscriber to use various broadcast services, an appropriate system must be provided for each service. In other words, since the communication service and the broadcasting service are not integrated, the subscriber in the home increases the cost of using various services and consequently increases the burden of providing the service.

Therefore, not only are technologies for convergence services provided through the convergence of broadcasting and telecommunications that receive Internet services and broadcasting services simultaneously through a single medium (for example, TV or PC), but also in different broadcasting services. Various technologies for providing a service using a communication network for various types of broadcast services using a medium have been studied.

As a part of this, the convergence service of broadcasting and communication provides a broadcasting service using a method using an existing cable TV network, a configuration in which an optical signal is overlaid on an existing communication line, or an IP packet and RTP in an internet network. A number of methods have been proposed, such as a method of integrating a broadcast service by applying Realtime Transfer Protocol. In addition, there is a method for accommodating data communication services such as high-speed Internet in a broadcasting network using a hybrid cable coaxial (HFC) network, or a method for accommodating multi-channel broadcasting using an IP Internet network.

However, there has not been a clear way to provide a service economically and efficiently to the home by fusing broadcast service and communication service through a single line and protocol. Therefore, there is a need for an efficient method that can accommodate all the services in which communication and broadcasting are converged on a single line that enters the home.

1 is a diagram showing the configuration of a cable TV network using the HFC currently installed among the various methods for providing a converged service.

The cable TV network of FIG. 1 provides a broadcast service to a subscriber by changing a channel received from a program provider (Program Provider (PP), 10) and a PP (10) that produces and supplies a broadcast program. It is composed of a system operator (11) for providing, a CATV delivery network (12) for delivering broadcast signals to the SO (11), and a cable TV subscriber distribution network (13) for delivering broadcast signals from the SO (11) to subscribers. .

Cable TV subscriber distribution network (13) is called HFC (Hybrid Fiber Coaxial) network because optical cable and coaxial cable are mixed from distribution center (14) to subscriber (15) and provides cable TV service and internet service at the same time. can do. The service provider SO 11 distributes the content received from the PP 10 to the subscribers, or distributes the broadcasting function Headend 111 for transmitting the broadcast signals to the subscribers by inserting their own advertisements or subtitles. Center, 112).

In the cable TV subscriber distribution network 13, there is an ONU (Optical Network Unit) 131, which converts the transmitted optical signal into an electrical signal (RF signal), and the broadcast data changed from the ONU 131 to the electrical signal is connected to the coaxial cable line. It is delivered to the subscriber by using the service, and the service is delivered to the subscriber by using the repeater and the splitter according to the distance.

The main purpose of cable TV networks using HFC is to provide cable TV broadcasting services, and attempts to combine Internet services, VOD (Video on demand) services, and telephone services using some of the bandwidth of installed networks. It is the most powerful way to simultaneously service broadcasting and communication.

However, the cable TV network is designed based on the broadcasting network and lacks the bandwidth for data communication for the Internet service, and the VOD broadcasting service is not easily serviced due to the bandwidth problem of the data communication. Although the cable technology standard of the new HFC network is currently enacted to accommodate VOD broadcasting service, the installation of new service equipment is required on the SO and subscriber side even when the technology standard is completed. The CATV delivery network 12 between the PP 10 and the SO 11 providing content in FIG. 1 uses an ATM network or a dedicated line. In case of using ATM, the transmission efficiency is low, and in case of using a dedicated line, the service cost of the line is high.

FIG. 2 is a diagram illustrating a network for implementing VOD broadcasting and Internet broadcasting service, which is another type of broadcasting service currently being provided, for VOD and Internet broadcasting to subscribers using IP multicast in an internet network configured as a router system. It shows the structure of network that transmits data.

Between the PP 10 and the edge router 20 serving the SO function, the broadcast MPEG data is encapsulated into an IP packet through a pre-allocated bandwidth in the IP multicast backbone network 21, and then over the Internet network. Transmission or broadcast data may be transmitted through a dedicated line. In the edge router 20, a subscriber network that transmits data to subscribers can be configured in a point-to-point or point-to-multipoint network, but must support the IP multicast function.

If the subscriber network consists only of Ethernet, Internet Group Message Protocol (IGMP) snooping or GARP Multicast Registration Protocol (GMRP) must be provided to support IP multicast.

Of the two communication broadcasting convergence service methods mentioned above, the convergence service of communication and broadcasting through the HFC network is a method of adding a communication service to the broadcasting service, and in the existing IP-based internet communication network, communication that accepts the broadcasting service on the communication infrastructure. And broadcast convergence services. However, the two methods have a disadvantage in that it is not easy to implement all services in a single network and a single platform by combining communication and broadcasting. There is a method using the EPON (Ethernet Passive Optical Network) network to solve this disadvantage.

3 is a diagram illustrating a configuration of an OLT for a broadcast service using an existing EPON network.

Conventional EPON Optical Line Terminal (OLT) uses four optical amplifiers 33 for analog video transmission of 16 ports, and each component consists of a separate rack. The all-optical converting unit 31 converts the electric signal of the cable TV broadcast into a predetermined light wavelength signal (1550 nm) and transmits it to the first 1x4 distribution unit 32, and the first 1x4 distribution unit 32 The optical signal is distributed and transmitted to four optical amplifiers 33. The broadcast signal amplified by each optical amplifier 33 is multiplexed with the EPON communication data optical signal via a WDM coupler 35 present in each EPON line card 36 via a second 1 × 4 distribution section 34. Transmitted to the EPON network.

As such, the existing EPON OLT consists of many components such as an all-optical converter 31, 1 × 4 distribution units 32 and 34, and four optical amplifiers 33, so that each component is a separate rack. The system configuration is complicated because it must be configured, and in particular, since the WDM coupler is integrated in the line card, it is not easy to change the wavelength band allocated to the cable TV broadcast or add a new wavelength for additional service.

Summarizing the problems of the existing broadcasting service method, there is a problem that the system configuration method is complicated and focuses on one of data or broadcasting, and the EPON system of FIG. 3 proposed as an alternative is expensive optical amplifier and distribution in hardware configuration. It is a structure that uses a large number of parts, and due to the integrated structure, it is difficult to modify or change according to the wavelength allocation.

Accordingly, the present invention has been made to solve the above problems, and the object and technical problem of the present invention are lower cost, simpler structure, and multi-channel broadcasting service and data on a single line (single ray) through a PON network. The present invention provides an OLT and an ONT that enable the convergence of communication services.

In order to achieve the above technical problem, in the passive optical network disclosed in the present invention, the OLT for providing a convergence service of a broadcast data service and a communication data service converts the broadcast data of an RF signal into a broadcast optical signal and transmits it to a subscriber side. A broadcast data transmitter; A communication data transmitter for converting communication data of an electrical signal into an optical signal for communication and transmitting the same to a subscriber; And a multiplexer for fusing the communication optical signal and the broadcast optical signal and multiplexing them into a single optical signal of multiple wavelengths in order to transmit the two optical signals to the subscriber side via a PON in a single light beam. Achieve the task

The multiplexing unit is a WDM coupler, and the WDM coupler is provided inside or outside of the OLT.

The broadcast data transmitter may include an all-optical converter configured to convert broadcast data of the input RF signal into the broadcast optical signal; A diverter for dividing the broadcast optical signal into a plurality of signals; And a WDM coupler module configured to multiplex each branched broadcast optical signal and the communication optical signal and output the multiplexed optical signal to the single optical path.

In addition, in order to achieve the above technical problem, in the passive optical network disclosed in the present invention, ONT for providing a converged service of a broadcast data service and a communication data service for broadcasting multiplexed optical signals transmitted through a single optical fiber of a PON network A WDM coupler separating the optical signal and the communication optical signal; And a photoelectric conversion unit converting the broadcast optical signal into an RF signal and outputting the RF signal to a broadcast service platform. The WDM coupler may be implemented as an independent module externally to achieve the object and technical problem of the present invention.

In addition, in order to achieve the above technical problem, in the passive optical network disclosed in the present invention, a method for transmitting and receiving a converged service for providing a converged service between a broadcast data service and a communication data service includes (a) broadcasting optical data of an RF signal. Converting the signal and converting communication data of the electrical signal into an optical signal for communication; (b) multiplexing the communication optical signal and the broadcast optical signal into a single optical signal of multiple wavelengths in order to transmit the two optical signals to a subscriber through a PON in a single light beam; (c) separating the multiplexed optical signal transmitted through the single optical path into the broadcasting optical signal and the communication optical signal; And (d) converting the broadcast optical signal into an RF signal and outputting the converted RF signal to a broadcast service platform to achieve the object and technical problem of the present invention.

Hereinafter, in order to clarify the technical spirit of the present invention, the configuration and operation thereof will be described in detail with reference to the accompanying drawings based on the embodiments of the present invention. Although the same reference numerals have been given even in different drawings, it will be appreciated that components of other drawings may be cited when necessary in describing the drawings.

The present invention is a structure of a distribution system and a terminal system for simultaneously serving broadcast and communication in existing FTTH (Fiber To The Home) type and FTTC (Fiber To The Curb) type subscriber networks that are constructed with optical cables such as EPON networks. We propose a communication / broadcasting convergence system that can minimize changes in the existing network structure.

4A is a diagram illustrating a network structure and a system structure capable of providing a broadcast service using a PON network according to the present invention.

Convergence service network of communication and broadcasting using PON network consists of OLT (41), splitter (42), WDM DMUX (43) which functions as an access system, and ONT (or ONU (44)) which is a subscriber device. It is composed.

The OLT 419 converts broadcast data and communication data into optical signals and distributes them to subscribers. The OLT 419 includes a broadcast data transmitter 411 and a communication data transmitter 412. The broadcast data transmitter 411 converts broadcast data (ie, an RF broadcast signal) of an electrical signal into a broadcast optical signal and performs a function of transmitting the broadcast signal. The communication data transmission unit 412 matches the communication data of the electrical signal, converts the signal into a communication optical signal, and transmits it to the subscriber, for example, to match and transmit IP-based communication data. This part delivers broadcast data.

Since the communication data transmission unit 412 performs a communication function, it performs a bidirectional optical transmission function, and in the PON network shown in FIG. 4A, bidirectional communication is performed using a single optical fiber, thereby generating two different wavelength (1490 nm and 1310 nm) optical signals. Apply to perform data communication function. Internet data communication is performed by applying 1490 nm for the downlink optical signal (OLT output signal) and 1310 nm for the uplink optical signal (OLT input signal).

The output optical signal wavelength 1550 nm of the broadcast data transmitter 411 should be different from the wavelength of the input / output optical signal of the communication data transmitter 412. The output optical signal of the broadcast data transmitter 411 and the communication data transmitter 412 is input to a transmission WDM MUX (or WDM coupler) 413, multiplexed into a single optical fiber, and output as a downlink optical signal. The input optical signal for communication is matched to the communication data transmitter 412.

As a result, three optical signals having different wavelengths (optical signals for broadcasting, optical signals for uplink communication data, optical signals for downlink communication data) exist for the convergence service of communication and broadcasting. The multiplexed multi-channel broadcast data is serviced by fusion into a single optical fiber.

In this case, the transmission WDM coupler 43 may exist as a functional block of the OLT 41 and may exist as a separate module outside the OLT 41.

The splitter 42 is a passive element for expanding the number of subscribers in a PON network and typically uses a 1 × 16 splitter. At this time, since the PON network is applied as an example of a subscriber network, even a network that transmits and receives is separated like a metro Ethernet network, and the applied optical fiber may not be a single optical fiber.

The receiving WDM coupler (WDM DMUX) 43 is a passive element located at the subscriber side and separates the optical signal wavelengths of the broadcast data transmitter 411 and the communication data transmitter 412 multiplexed by the transmit WDM coupler 413. Let's do it. The ONT 44 receives the separated broadcast optical signal and the communication data optical signal, converts them into electrical signals, and transmits them to a service platform such as a CATV STB or a satellite STB and a PC. At this time, the service platform may be composed of several according to each characteristic or may be built on a single platform.

FIG. 4B is a diagram illustrating a configuration of a preferred embodiment of the broadcast data transmitter shown in FIG. 4A.

The broadcast data transmitter 411 includes an all-optical converter 4111, an optical amplifier 4112, a 1 × 16 splitter 4113, and a WDM coupler module 4114. The broadcast data electrical signal (RF broadcast signal) input through the coaxial cable is converted into an optical signal having a wavelength of 1550 nm by the all-optical converter 4111 (S1) and amplified by the optical amplifier 4112 and then 1 × 16 branching unit 4113. It is branched into 16 by). The sixteen branched signals are input to the WDM coupler module 4114.

The WDM coupler module 4114 functions to multiplex up and down the communication optical signal of 1490 / 1310nm wavelength and the broadcasting optical signal of 1550nm wavelength (S2) and output it as one optical fiber, and to accommodate 16 PON networks It consists of a WDM coupler. The WDM coupler module 4114 may be located inside or outside the broadcast data transmitter 411 according to the configuration of the OLT 41, but the functions and roles thereof are the same.

4C is a diagram illustrating still another configuration of the preferred embodiment of the broadcast data transmission unit shown in FIG. 4A.

As shown in FIG. 4B, the input broadcast data of the transmitter is an RF signal. Unlike FIG. 4B, however, the RF broadcast signal is first divided into 16 through 1 × 16 RF splitters, and then all-optical conversion is performed and optical amplification is performed for each. The amplified optical signal is multiplexed through the WDM coupler module in the same manner as in FIG. 4A and transmitted to the subscriber side.

FIG. 4D is a diagram showing the configuration of one preferred embodiment of the ONT shown in FIG. 4A.

The multiplexed optical signal transmitted from the OLT 41 through a single optical path is separated into a broadcasting optical signal (1550 nm) and a communication optical signal (1490 nm) through the receiving side WDM coupler 441 (S3), and optically separated by wavelength. Among the signals, the broadcast optical signal having a wavelength of 1550 nm is converted into an RF signal by the photoelectric conversion unit 442 and output (S4) to a broadcast service platform such as an STB or a TV. The downlink optical signal having a wavelength of 1490 nm communicates with the EPON path 443. Output to a data service platform such as a PC. The communication signal going upward from the PC is made into an optical signal of 1310 nm wavelength via the EPON path 443 and input to the WDM coupler 441.

The receiving side WDM coupler 441 may also be implemented as an independent module outside the ONT (or ONU) according to the system configuration. FIG. 4D illustrates that the WDM coupler 441 is located inside the ONT.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

In the present invention, as described above, by using a single line through the PON network, a broadcast signal is converted into an optical signal, and the structure of the PON network and system for simultaneously providing broadcast data and communication data service by wavelength-multiplexing up and down communication data are provided. I'm proposing. The broadcast service method using a single line communication network in the PON network has various advantages over the conventional internet network or broadcasting network.

The most distinctive merit is that broadcasting can be combined with communication in the simplest way to provide subscribers with all services through a single optical subscriber network, and to directly transmit RF signals regardless of analog or digital broadcasting. It is simpler to implement than the convergence method of communication and broadcasting, which converts and provides a broadcasting service on the Internet.

In addition, the structure of the PON system proposed for fusion broadcasting in the present invention is simply implemented as compared to the conventional system configuration method by separately configuring a broadcast service module, and it is possible to reduce expensive components such as an optical amplifier, thereby economically implementing the PON system. The advantage is that it is possible. In addition, since the broadcasting module can be implemented in the form of a selection function, there is an advantage that it can have a flexible structure according to the service method and the installation method.

Claims (5)

An all-optical converting unit converting the broadcast data of the input RF signal into an optical signal for broadcasting; A diverter for branching the broadcast optical signal into a plurality of signals; A WDM coupler module for multiplexing each branched broadcast optical signal; A communication data transmitter for converting communication data of an electrical signal into an optical signal for communication and transmitting the same to a subscriber; And Passive optical network comprising a multiplexer for fusion of the optical signal for communication and the optical signal for broadcasting and multiplexing into a single optical signal of multiple wavelengths in order to transmit the two optical signals to the subscriber side via a PON. OLT for providing convergence service of broadcasting data service and communication data service in. A diverter for branching the RF signal of the input broadcast data into a plurality of signals; An all-optical conversion unit converting each branched RF signal into a broadcast optical signal; A WDM coupler module for multiplexing each branched broadcast optical signal; A communication data transmitter for converting communication data of an electrical signal into an optical signal for communication and transmitting the same to a subscriber; And Passive optical network comprising a multiplexer for fusion of the optical signal for communication and the optical signal for broadcasting and multiplexing into a single optical signal of multiple wavelengths in order to transmit the two optical signals to the subscriber side via a PON. OLT for providing convergence service of broadcasting data service and communication data service in. The method according to claim 1 or 2, The multiplexer OLT for providing a converged service of a broadcast data service and a communication data service in a passive optical network, characterized in that provided inside or outside the OLT. A WDM coupler for separating the multiplexed optical signal transmitted through a single optical path of the PON network into a broadcast optical signal and a communication optical signal; And A photoelectric conversion unit converting the broadcast optical signal into an RF signal and outputting the converted RF signal to a broadcast service platform; The WDM coupler is ONT for providing a convergence service of a broadcast data service and a communication data service in a passive optical network, characterized in that the external module can be implemented. delete

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