JP2020014068A - Ip broadcast system - Google Patents

Abstract

To realize an IP broadcast system that can support large-capacity services.SOLUTION: In an IP broadcast device 10, an IP broadcast signal (electric signal) is generated and converted into an IP broadcast signal (optical signal), amplified by an optical amplifier 12, and then the IP broadcast signal (optical signal) is transmitted to each IP broadcast optical terminal 14 connected to a splitter 13. The IP broadcast optical terminal 14 converts the IP broadcast signal (optical signal) received from the splitter 13 into an IP broadcast signal (electric signal). An IP-STB 15 transmits information on a channel selected by a subscriber to the IP broadcast optical terminal 14. The IP broadcast optical terminal 14 stores the information on the selected channel, extracts only an IP broadcast signal of a predetermined channel from the IP broadcast signal (electric signal), and transmits the extracted signal to the IP-STB 15. The IP-STB 15 transmits an IP broadcast signal of a predetermined channel to a TV 16.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an IP broadcast system that performs IP broadcast using an IP (Internet Protocol) network.

  2. Description of the Related Art Conventionally, as a system for transmitting a broadcast such as a terrestrial digital broadcast or a BS digital broadcast via an FTTH network, a system for converting an RF electric signal into an optical signal and transmitting the optical signal has been widely known. In addition, IP broadcasting in which an RF signal is converted into an IP signal and transmitted via an FTTH network is also performed. In the case of performing such an IP broadcast, conventionally, an IP broadcast signal is multiplexed on an IP communication network that provides an IP communication service such as the Internet, VOD (video on demand), and telephone.

Japanese Patent No. 6298305

  However, with the start of various services associated with the Internet of Things (IoT), IP communication traffic has been increasing. In addition, since the 4K / 8K broadcasting is started from 2018, the number of channels may increase, and it is expected that the traffic of the IP broadcasting will also increase. Therefore, when multiplexing an IP broadcast to an existing IP communication system, the communication speed is not sufficient with the currently widely used schemes such as the GE-PON and the G-PON, and the number of broadcast channels is reduced, and the number of broadcast channels per OLT is reduced. It is necessary to reduce the number of ONU connections, and it has not been possible to construct an IP broadcast system sufficiently compatible with large-capacity IP broadcasts such as 4K / 8K broadcasts. Further, there is a possibility that the system becomes unstable due to an increase in traffic due to IP broadcasting. Therefore, in the method of multiplexing the IP broadcast in the IP communication system, it is necessary to switch to a method faster than the existing GE-PON or G-PON, for example, 10G-EPON, 10G-PON, NG-PON2, etc. It was necessary to change to an expensive communication device corresponding to the system. In addition, it is necessary to replace communication devices such as L2 switches, L3 switches and routers used in the upper line with more expensive communication devices, or to update existing communication devices to high-speed systems. Was.

  Therefore, an object of the present invention is to provide an IP broadcasting system capable of supporting large-capacity IP broadcasting.

  The present invention relates to an IP broadcast system provided with an IP communication network for performing IP communication and an IP broadcast network for performing IP broadcast independently of the IP communication network, wherein the IP broadcast network is arranged on a center side. And an IP broadcast device for transmitting an IP broadcast signal as an optical signal, and an IP broadcast signal arranged at each subscriber's house, receiving the IP broadcast signal from the IP broadcast device via an optical fiber network, and converting the received IP broadcast signal into an IP broadcast signal as an electric signal. An IP broadcast optical terminal to be converted and an IP-STB arranged at each subscriber's home and performing IP communication with the IP broadcast optical terminal, wherein the IP-STB is selected by the subscriber for the IP broadcast optical terminal. The IP broadcast optical terminal extracts the signal of the selected channel from the IP broadcast signal based on the channel information from the IP-STB, transmits the signal to the IP-STB, and transmits the signal to the IP-STB. STB is And it outputs the IP broadcast signal of the selected channel from the IP broadcast optical terminal, an IP broadcasting system, characterized in that.

  In the present invention, out of the IP communication, a downstream IP communication signal of a predetermined IP communication service such as a video distribution service is multiplexed with an IP broadcast signal and transmitted from the center to each subscriber's home, and the predetermined IP communication The upstream IP communication signal of the service may be transmitted from each subscriber's house to the center via the IP communication network. The traffic on the IP communication side can be further reduced.

  In the present invention, an IP notification broadcast device for transmitting an IP notification broadcast signal for performing IP notification broadcast is provided at the center side, the IP notification broadcast signal is multiplexed with the IP broadcast signal, and the IP broadcast signal is transmitted. The notification broadcast signal may be transmitted to the IP-STB, and the IP-STB may output the received IP notification broadcast signal. Also, in the present invention, an IP radio broadcast device for transmitting an IP radio broadcast signal for performing an IP radio broadcast is provided on the center side, the IP broadcast signal is multiplexed with the IP broadcast signal and transmitted, and the IP broadcast optical terminal receives the IP broadcast signal. The transmitted IP radio broadcast signal may be transmitted to the IP-STB, and the IP-STB may output the received IP radio broadcast signal.

  In the present invention, an RF broadcast network for performing RF broadcast may be further provided, and the RF broadcast signal may be wavelength-multiplexed with the IP broadcast signal and transmitted. RF broadcasting and IP broadcasting can coexist.

  In addition, the IP broadcast network may perform only downstream IP broadcast.

  Further, the optical fiber network may have a structure in which one amplifier and one splitter are taken as one unit, and the units are combined in multiple stages and branched in a tree shape. Further, the number of branches of the optical fiber network in the IP broadcast network may be larger than the number of branches of the optical fiber network in the IP communication network. Here, the branch includes distribution. Further, the transmission distance of the IP broadcast network may be longer than the transmission distance of the IP communication network.

  According to the present invention, it is possible to realize an IP broadcasting system capable of supporting a large-capacity service such as 4K / 8K broadcasting. Further, in the present invention, since the IP broadcast side is independent of the IP communication side, the IP broadcast can be stably performed without increasing the traffic of the communication network on the IP communication side. Further, since the IP broadcast side is not restricted by the standards of the IP communication side, it is possible to optimize each of the IP broadcast side and the IP communication side. Further, the IP broadcast system of the present invention does not need to change the IP communication network, and can be constructed by using an existing RF signal broadcast system. For example, an optical amplifier or an optical distributor can be used. So it is low cost.

FIG. 1 is a diagram illustrating a configuration of an IP broadcast system according to a first embodiment. FIG. 6 is a diagram illustrating a configuration of an IP broadcast system according to a second embodiment. FIG. 9 is a diagram illustrating a configuration of an IP broadcast system according to a third embodiment. FIG. 9 is a diagram illustrating a configuration of an IP broadcast system according to a fourth embodiment. The figure which showed the example of a branch of an optical fiber network. The figure which showed the structure of the IP broadcast system of a modification.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments.

  FIG. 1 is a diagram illustrating the configuration of the IP broadcast system according to the first embodiment. As shown in FIG. 1, the IP broadcast system according to the first embodiment is a system that provides both an IP broadcast service and an IP communication service to a subscriber through an FTTH network, and the IP broadcast network and the IP communication network are provided independently. Have been. Here, that the IP broadcast network and the IP communication network are independent means not only a case in which the optical fibers are physically independent, such as by using separate optical fibers, but also a case where the same optical fiber is used for wavelength multiplexing. This includes the case where the optical signal on the IP broadcast side and the optical signal on the IP communication side can be transmitted and received without interfering with each other.

  The IP broadcast network includes an IP broadcast device 10, an optical amplifier 12, a splitter 13, an IP broadcast optical terminal 14, and an IP-STB (set-top box) 15. The IP communication network includes an IP communication device 20, a multiplexing device 26, an OLT (provider side optical line terminal) 21, a splitter 22, an ONU (subscriber side optical line terminal) 23, an HGW (Home gateway) 24. The IP broadcast device 10, the multiplexing device 26, the optical amplifier 12, the IP communication device 20, and the OLT 21 are arranged at the center side, and the IP broadcast optical terminal 14, IP-STB 15, ONU 23, and HGW 24 are arranged at each subscriber's house. ing. Hereinafter, each configuration will be described.

(Configuration on the IP broadcast side)
The IP broadcast device 10 is a device that unidirectionally broadcasts an IP broadcast signal to the IP broadcast optical terminal 14 of each subscriber. Multicast or unicast transmission may be used. The IP broadcast signal is obtained by converting a digital broadcast signal such as a terrestrial digital broadcast signal, a BS / CS digital broadcast signal, a multi-channel broadcast signal, and an independent broadcast signal into an IP signal (electric signal). A program information signal may be inserted into the IP broadcast signal as needed. Here, the program information signal is a signal for requesting the IP broadcast optical terminal 14 via the IP-STB 15 for the predetermined channel when the subscriber selects a predetermined channel from a number of channels of the IP broadcast. Refers to information. Also, a channel means any stream signal such as a content or a program.

  In the IP broadcast device 10, the IP broadcast signal is converted from an electric signal to an optical signal and transmitted. In the following, in order to discriminate whether a signal is an optical signal or an electric signal, the effect is added in parentheses. The wavelength of the optical signal is, for example, in the 1550 nm band. The IP broadcast device 10 is connected to an optical amplifier 12 via an optical fiber. In the IP broadcasting system according to the first embodiment, a large-capacity broadcasting service such as 4K / 8K broadcasting can be easily realized because a large-capacity broadcasting service can be realized.

  The optical amplifier 12 has an input side of the optical signal connected to the IP broadcast apparatus 10 and an output side of the optical signal connected to the splitter 13 via an optical fiber. The optical amplifier 12 is a device that amplifies and outputs an input IP broadcast signal (optical signal). For example, an EDFA (erbium-doped fiber amplifier) is used. The amplified IP broadcast signal (optical signal) is split (divided) into a plurality by the splitter 13. Here, the term “branch” means that an input optical signal is divided into a plurality of optical signals, and includes a case where the output levels of the divided optical signals are not the same. On the other hand, the distribution means that an input optical signal is divided into a plurality of optical signals, and the divided optical signals have the same output level. In this specification, the expression "branch" includes distribution.

  Here, in the first embodiment, since the IP broadcast side is independent from the IP communication side, the IP broadcast side is not restricted by the standard of the IP communication side. Therefore, a splitter 13 having a greater number of branches than the splitter 22 on the IP communication side may be used, or a transmission distance (the largest transmission distance from the center to the subscriber's home, more specifically, the IP broadcast device 10 It is possible to increase the transmission distance from the IP broadcast optical terminal 14 to the IP broadcast optical terminal 14). For example, in the case of the GE-PON, the transmission distance is 20 km according to the standard, but the transmission distance of the IP broadcast network of the first embodiment can be longer than 20 km.

  For example, the following three methods are available for increasing the transmission distance, and a plurality of these methods may be combined. One is a method of inserting two or more optical amplifiers 12 between the center and the subscriber's house. Another method is to extend the transmission distance by inserting a dispersion compensating fiber and performing dispersion compensation on the optical fiber. Another method is to extend a transmission distance by inserting a repeater into an optical fiber between a center and a subscriber's house. Here, the repeater is a device that converts an optical signal into an electric signal and then converts the electric signal into an optical signal again, and is a device having at least two functions of an optical amplification function, a waveform shaping function, and a timing reproduction function. is there.

  Also, by providing a plurality of optical amplifiers 12 and splitters 13 in multiple stages, the number of branches can be further increased. FIG. 5 shows a structure in which a configuration in which one optical amplifier 12 and one splitter 13 are connected is defined as one unit, and the units are combined in two stages and branched in a tree shape. By branching in a tree shape in this manner, a larger number of branches can be realized. Although FIG. 5 shows a combination of two stages, a combination of three or more stages may be used.

  Since the wavelength of the IP broadcast signal (optical signal) is not limited, the use of a semiconductor optical amplifier (SOA) as the optical amplifier 12 allows not only the number of branches and the transmission distance, but also the degree of freedom in selecting the wavelength of the optical signal. Can also be improved. For example, in the case of the GE-PON, the wavelength is standardized in the downstream 1490 nm band and upstream 1310 nm band. However, the wavelength of the IP broadcast signal (optical signal) in the first embodiment can be selected from other wavelengths.

  The IP broadcast optical terminal 14 is a device that receives an IP broadcast signal (optical signal), converts the signal into an IP broadcast signal (electric signal), extracts a predetermined channel, and outputs it. I have. A plurality of channels may be extracted and output. In that case, for example, time-division multiplexing is performed and output. An IP broadcast signal (optical signal) input side of the IP broadcast optical terminal 14 is connected to a branch side of the splitter 13 via an optical fiber, and an IP broadcast signal (electric signal) output side is connected to the IP-STB 15. I have. The IP broadcast optical terminal 14 and the IP-STB 15 perform bidirectional IP communication. This IP communication is performed by unicast, but is not necessarily limited thereto. For example, multicast or broadcast communication may be performed between the IP broadcast optical terminal 14 and a plurality of IP-STBs 15.

  The IP-STB 15 is connected to the IP broadcast optical terminal 14 and a TV (television receiver) 16, and performs bidirectional IP communication (for example, communication such as unicast) with the IP broadcast optical terminal 14. The IP-STB 15 is a device that receives an IP broadcast signal (electric signal) of a predetermined channel from the IP broadcast optical terminal 14 and outputs the signal to the TV 16. The IP broadcast signal (electric signal) may be output as it is, or may be converted into an HDMI (registered trademark) signal and output. How each operates by IP communication between the IP broadcast optical terminal 14 and the IP-STB 15 will be described in detail later in the description of the operation of the IP broadcast system.

  Note that the IP broadcast optical terminal 14 and the IP-STB 15 may be integrated into one device. Similarly, the IP-STB 15 and the TV 16 may be integrated into one device, or the IP broadcast optical terminal 14, the IP-STB 15 and the TV 16 may be integrated into one device. The receiver that receives the IP broadcast is not limited to the TV 16, but may be any receiver such as a smartphone or a tablet. The connection between the receiver and the IP-STB 15 may be wireless or wired. . Further, a plurality of receivers may be connected to one IP-STB 15.

(Configuration of IP communication side)
The IP communication device 20 is a device for transmitting and receiving IP communication signals corresponding to various IP communication services such as the Internet, telephone, VOD, OTT, VR / AR distribution, game distribution, and the like. This is a device that performs unicast communication with a communication terminal. The IP communication signals of various IP communication services are multiplexed by the multiplexer 26 and output to the OLT 21. The upstream IP communication signal from the OLT 21 is distributed by the multiplexing device 26 for each of various IP communication services, and is output to various IP communication devices of the IP communication device 20.

  The OLT 21 converts a downstream IP communication signal, which is an electric signal from the multiplexer 26, into an optical signal and outputs the same, and converts an upstream IP communication signal, which is an optical signal from the splitter 22, into an electric signal and outputs the same. It is a device having functions such as: The wavelength of the optical signal is, for example, a 1490 nm band for the downstream and a 1310 nm band for the upstream. The IP communication signal output from the OLT 21 is split (divided) by the splitter 22 into a plurality.

  In the first embodiment, the electric signal is multiplexed by the multiplexer 26 and then converted to an optical signal by the OLT 21. However, the electric signal may be converted to an optical signal first and then multiplexed. It is not necessary to have a function of converting an electric signal to an optical signal or from an optical signal to an electric signal, and the input and output may be both optical signals or electric signals.

  The ONU 23 is connected to the split side of the splitter 22 and the HGW 24. The ONU 23 is a device that converts an IP communication signal, which is an optical signal from the splitter 22, into an electrical signal and outputs the electrical signal to the HGW 24, and converts the IP communication signal, which is an electrical signal from the HGW 24, into an optical signal and outputs the optical signal to the splitter 22, It is located at each subscriber's home.

  The HGW 24 is connected to various communication terminals such as a PC (personal computer), an IP phone, a smartphone, and a tablet by wire or wirelessly. In the figure, only the PC 25 is shown as a representative. The HGW 24 receives the downstream IP communication signal from the ONU 23, distributes and transmits it to various communication terminals, receives and multiplexes the upstream IP communication signal from various communication terminals, and transmits the multiplexed signal to the ONU 23. The ONU 23 and the HGW 24 may be integrated into a single device. Further, any two or more of the IP broadcast optical terminal 14, the IP-STB 15, the ONU 23, and the HGW 24 may be integrated into one device.

  Next, the operation of the IP broadcast system according to the first embodiment will be described. First, the operation on the IP broadcast side will be described.

  On the IP broadcast side, one-way broadcast communication is performed from the IP broadcast apparatus 10 to the IP broadcast optical terminal 14, and bidirectional unicast communication is performed between the IP broadcast optical terminal 14 and the IP-STB 15. Specifically, it is as follows.

  The IP broadcast device 10 generates an IP broadcast signal (electric signal) by multiplexing signals such as a terrestrial digital broadcast signal and a BS / CS digital broadcast signal. Further, a program information signal corresponding to a channel included in the IP broadcast signal (electric signal) may be inserted as needed. Then, the IP broadcast signal (electric signal) is converted into an IP broadcast signal (optical signal), and after being amplified by the optical amplifier 12, the IP broadcast signal (optical signal) is transmitted to each IP broadcast optical terminal 14 connected to the splitter 13. To broadcast.

  The IP broadcast optical terminal 14 converts the IP broadcast signal (optical signal) received from the splitter 13 into an IP broadcast signal (electric signal). When a program information signal is inserted into the IP broadcast signal (electric signal), the program information signal is transmitted to IP-STB 15. The IP-STB 15 transmits the program information signal to the TV 16 so that a program guide based on the program information signal is displayed on the TV 16. Further, the IP-STB 15 transmits to the IP broadcast optical terminal 14 information on the channel selected by the subscriber using a remote controller or the like. In addition, any means can be adopted as long as the means directly or indirectly inputs the selected channel information to the IP-STB 15 irrespective of wired or wireless means. The IP broadcast optical terminal 14 stores the information of the selected channel, extracts only the IP broadcast signal of the predetermined channel from the IP broadcast signal (electric signal), and transmits it to the IP-STB 15. The IP-STB 15 transmits an IP broadcast signal (electric signal) of a predetermined channel to the TV 16, and the TV 16 outputs a video of the predetermined channel based on the IP broadcast signal (electric signal). As described above, the IP broadcast is performed from the center to each subscriber.

  Note that a plurality of IP-STBs 15 may be provided. If a plurality of channels are provided, many channels can be viewed simultaneously. In addition, if a receiver such as a TV, a smartphone, and a tablet on which an application corresponding to the IP broadcast is installed is used, the IP communication with the IP broadcast optical terminal 14 is performed by unicast in the same manner as the IP-STB 15, so that the IP broadcast is transmitted via the IP-STB 15. It is possible to view the IP broadcast directly or wirelessly without using a cable.

  Next, the operation on the IP communication side will be described. The operation on the IP communication side is the same as that of the conventional PON-based IP communication. That is, with respect to downstream communication, the downstream IP communication signal from the IP communication device 20 is multiplexed by the multiplexer 26, the multiplexed IP communication signal (electric signal) is converted into an optical signal by the OLT 21, and the splitter 22 Branch (distribute). Then, the ONU 23 in each subscriber's home converts the IP communication signal (optical signal) from the splitter 22 into an electric signal, and distributes and outputs the electric signal to various communication terminals by the HGW 24.

  On the other hand, for upstream communication, upstream IP communication signals (electric signals) from various communication terminals are multiplexed by the HGW 24 and converted into optical signals by the ONU 23. Then, the IP communication signal (optical signal) is received by the OLT 21 via the splitter 22, converted into an electric signal, and the multiplexer 26 sorts and outputs the IP communication signal for each of various services.

  As described above, in the IP broadcast system according to the first embodiment, the IP broadcast side is provided independently of the IP communication side, so that the IP broadcast can be stably performed without being affected by the traffic on the IP communication side.

  Further, since the IP broadcast side is not tied to the standard of the IP communication side, the operation efficiency can be optimized on both the IP broadcast side and the IP communication side. For example, the IP broadcast side can sufficiently amplify and transmit the IP communication signal by the optical amplifier 12 and is more resistant to distortion and the like than the RF broadcast, so the number of branches by the splitter 13 on the IP broadcast side is determined by the IP communication side. The number of branches by the splitter 22 on the side can be increased. That is, the number of subscribers per IP broadcast apparatus 10 can be made larger than the number of subscribers per OLT 21, and a more efficient IP broadcast system can be constructed. Also, for example, the transmission distance on the IP broadcast side can be longer than the transmission distance on the IP communication side.

  In the IP broadcast system according to the first embodiment, one-way broadcast communication from the IP broadcast device 10 to each IP broadcast optical terminal 14 is performed, and is independent of the IP communication. Also, unlike an RF signal, an IP broadcast signal has no band limitation. Therefore, a large-capacity broadcast service can be realized. For example, many channels including 4K / 8K broadcast channels can be transmitted simultaneously.

  In the IP broadcast system of the first embodiment, the communication between the IP broadcast optical terminal 14 and the IP-STB 15 is bidirectional unicast communication or the like. Since only the signal is transmitted, the IP broadcast can be performed more stably.

  In the IP broadcasting system according to the first embodiment, the optical amplifier 12, the splitter 13, and the optical fiber network can be used as they are among the existing RF signal broadcasting systems. Therefore, it is possible to easily and inexpensively switch or add the existing RF signal broadcast system to the IP broadcast system of the first embodiment.

  In the first embodiment, the IP broadcast is one-way communication from the center side to the subscriber, but may be two-way communication. In that case, the upstream communication from the subscriber to the center side may use an IP broadcast network, or may use an IP communication network as in a third embodiment described later.

  As shown in FIG. 2, the IP broadcast system according to the second embodiment differs from the IP broadcast system according to the first embodiment in that an IP notification broadcast device 30 and a multiplexing device 31 are added to the center side, and an IP notification broadcast terminal is provided to the subscriber side. 32 is added. The IP notification broadcast device 30 is a device that transmits an IP notification broadcast signal (optical signal) of the IP system. The multiplexing device 31 is a device that multiplexes an IP broadcast signal (optical signal) from the IP broadcast device 10 and an IP notification broadcast signal (optical signal) from the IP notification broadcast device 30 and outputs the multiplexed signal to the optical amplifier 12. First, the IP broadcast signal (electric signal) and the IP announcement broadcast signal (electric signal) may be multiplexed and then converted to an optical signal. The IP notification broadcast terminal 32 is connected to the IP-STB 15.

  The IP notification broadcast signal (optical signal) from the IP notification broadcast device 30 is multiplexed with the IP broadcast signal (optical signal) and broadcasted to each IP broadcast optical terminal 14. Then, the signal is converted into an IP announcement broadcast signal (electric signal) by the IP broadcast optical terminal 14 and output to the IP-STB 15. Further, the IP notification broadcast signal (electric signal) is output from the IP-STB 15 to the IP notification broadcast terminal 32, and the IP notification broadcast terminal 32 outputs a notification broadcast.

  As described above, the IP announcement broadcast, which is a one-way IP communication service from the center side to the subscriber, can be multiplexed with the IP broadcast in the IP broadcast system according to the first embodiment. In addition to the IP announcement broadcast, for example, an IP radio broadcast can be multiplexed into the IP broadcast. If the IP announcement broadcast includes a plurality of channels or is an IP radio broadcast, communication control is performed between the IP broadcast optical terminal 14 and the IP-STB 15 in the same manner as in the first embodiment, and the selected IP broadcast is selected. The control may be performed so that only the channel is transmitted to the IP-STB 15, or all the channels may be transmitted to the IP-STB 15 and the IP-STB 15 may select a channel.

  In the second embodiment, the IP notification broadcast is one-way communication from the center side to the subscriber, but may be two-way communication. In that case, the upstream communication from the subscriber to the center side may use an IP broadcast network, or may use an IP communication network as in a third embodiment described later.

  As shown in FIG. 3, the IP broadcast system of the third embodiment is different from the IP broadcast system of the first embodiment in that a multiplexing device 40 replaces the multiplexing device 26 and an IP broadcast optical terminal 44 replaces the IP broadcast optical terminal 14. , The ONU 43 is used in place of the ONU 23, and the IP broadcast optical terminal 44 and the ONU 43 are connected.

  The multiplexing device 40 is connected to the IP broadcasting device 10, the IP communication device 20, the optical amplifier 12, and the OLT 21. The multiplexing device 40 converts an IP broadcast signal (electric signal) input from the IP broadcast device 10 into an optical signal and outputs the optical signal to the optical amplifier 12. With respect to an IP communication signal (electric signal) input from the IP communication device 20, a signal of a video distribution service such as VOD or OTT is multiplexed into an IP broadcast signal (electric signal), converted into an optical signal, and output to the optical amplifier 12. Then, signals of other services such as telephone and the Internet are output to the OLT 21. Also, the upstream IP communication signal (electric signal) from the OLT 21 is distributed and output for various services such as the Internet, telephone, VOD, and OTT. In the third embodiment, the IP communication signal and the IP broadcast signal are multiplexed at the stage of the electric signal, but may be multiplexed after being converted into an optical signal.

  The IP broadcast optical terminal 44 converts the signal received from the splitter 13 from an optical signal to an electric signal, and includes a downstream IP communication signal (electric signal) related to a video distribution service via the IP-STB 15 or the ONU 43. Output to HGW24. Then, the user can view the video distribution service on the receiver, for example, the TV 16 via the IP-STB 15 in which the application corresponding to the video distribution service is installed. The receiver that receives the video distribution service is not limited to the TV 16, but may be any receiver such as a smartphone or a tablet, and the connection between the receiver and the IP-STB 15 may be wireless or wired. Good.

  Further, the HGW 24 distributes downstream IP communication signals (electric signals) related to the video distribution service to various communication terminals such as the PC 25. This allows the PC 25 to view the video by the video distribution service. In addition, by using a TV, a smartphone, a tablet, or the like on which an application corresponding to the IP broadcast is installed, the IP broadcast optical terminal 44 and the IP broadcast optical terminal 44 perform IP communication in a unicast manner, thereby directly viewing the video by the video distribution service. You can also.

  In order to receive video data from the video distribution service, it is necessary to request the IP communication device 20 to transmit video data from the IP-STB 15 or the PC 25. An upstream IP communication signal (electric signal) relating to a video distribution service from such an IP-STB 15 or PC 25 is input to the ONU 43 via the IP broadcast optical terminal 44 or the HGW 24. Then, the ONU 43 converts the IP communication signal (electric signal) into an IP communication signal (optical signal), and inputs the converted signal to the OLT 21 via the splitter 22. In the OLT 21, the IP communication signal (optical signal) is converted into an IP communication signal (electric signal) and input to the VOD or OTT IP communication device 20. In this manner, the IP communication device 20 can receive the upstream IP communication signal (electric signal) related to the video distribution service, and transmit the video data corresponding to the request as the downstream IP communication signal (electric signal). Can be. The transmission request may be transmitted via a communication network other than the IP broadcasting network and the IP communication network, such as a telephone network such as a smartphone and a mobile phone.

  The IP broadcast system according to the third embodiment has the following advantages. Among various IP communication services, a video distribution service such as VOD or OTT has a small communication traffic due to a request for video data in uplink communication, whereas a downstream communication is video data and large traffic in downlink communication. Therefore, there are cases where it is desired to reduce traffic. In such a case, the IP broadcast system according to the third embodiment is effective, and by multiplexing the downstream IP broadcast signal of the video distribution service with the IP broadcast signal, traffic on the IP communication side can be reduced. Of course, for one or more predetermined IP communication services other than the video distribution service, the downstream may be an IP broadcast network and the upstream may be another communication network as in the third embodiment.

  In addition, in the IP broadcasting system of the third embodiment, when the notification broadcast is added by wavelength multiplexing as in the second embodiment, the upstream communication of the IP notification broadcast signal is transmitted via the IP communication network as in the third embodiment. (See FIG. 6).

  As shown in FIG. 4, the IP broadcast system of the fourth embodiment is a system that coexists with the IP broadcast by wavelength-multiplexing the RF broadcast. Since the configuration on the IP communication side is the same as that of the IP broadcast system of the first embodiment shown in FIG. 1, the description thereof is omitted below, and the illustration is also omitted in FIG.

  The IP broadcast system according to the fourth embodiment is different from the IP broadcast system according to the first embodiment in that an RF broadcast device 50, a V-ONU 51, and an RF-STB 52, which are devices on the RF broadcast side, and wavelength multiplexing devices (WDMs) 53 and 54 are included. This is an added configuration. The RF broadcast device 50 and the wavelength multiplexing device 53 are arranged on the center side, and the V-ONU 51, the RF-STB 52, and the wavelength multiplexing device 54 are arranged at the subscriber's house.

  The RF broadcast device 50 is a device that converts an RF broadcast signal (electric signal) into an RF broadcast signal (optical signal) and transmits the signal. The wavelength of the RF broadcast signal (optical signal) is, for example, in the 1550 nm band, and is different from the IP broadcast signal (optical signal). Here, if the wavelengths of the RF broadcast signal (optical signal) and the IP broadcast signal (optical signal) are within a wavelength band that can be amplified by the EDFA, both can be amplified by the optical amplifier 12 that is an EDFA. As a specific example, the wavelength of the RF broadcast signal (optical signal) is 1555.75 nm, and the wavelength of the IP broadcast signal (optical signal) is 1557.36 nm.

  The wavelength multiplexing device 53 is connected to the RF broadcasting device 50, the IP broadcasting device 10, and the optical amplifier 12, and the RF broadcasting signal (optical signal) from the RF broadcasting device 50 and the IP broadcasting signal (optical signal) from the IP broadcasting device 10 This is a device that wavelength-multiplexes an optical signal) and outputs it to the optical amplifier 12.

  The wavelength multiplexing device 54 is connected to the branch side of the splitter 13, the V-ONU 51, and the IP broadcast optical terminal 14, and multiplexes the wavelength multiplexed signal from the splitter 13 into an RF broadcast signal (optical signal) and an IP broadcast signal (optical signal). ), And output to the V-ONU 51 and the IP broadcast optical terminal 14, respectively.

  The V-ONU 51 is connected to the wavelength multiplexing device 54 and the RF-STB 52, and converts the RF broadcast signal (optical signal) from the wavelength multiplexing device 54 into an RF broadcast signal (electric signal) and outputs the signal to the RF-STB 52. is there. The RF-STB 52 is a device that is connected to the V-ONU 51 and the TV 16, extracts an RF broadcast signal of a predetermined channel selected by a remote controller or the like from an RF broadcast signal (electric signal) from the V-ONU 51, and outputs the extracted signal to the TV 16. . In this way, the TV 16 can watch the RF broadcast of the desired channel.

  It is not necessary to provide the wavelength multiplexing device 54 at the subscriber's home where only the RF broadcast is viewed. Since the IP broadcast signal (optical signal) is more resistant to distortion than the RF broadcast signal (optical signal), the level of the IP broadcast signal (optical signal) can be lower than that of the RF broadcast signal (optical signal). Therefore, if the level of the IP broadcast signal (optical signal) does not affect the RF broadcast signal (optical signal), even if the wavelength-multiplexed signal is directly received by the V-ONU 51, the signal is converted into the RF broadcast signal (electric signal). can do.

  Also, at a subscriber's house where only IP broadcasts are viewed, if a wavelength filter that incorporates a wavelength filter that transmits only the IP broadcast signal (optical signal) wavelength band is used as the IP broadcast optical terminal 14, a wavelength multiplexing apparatus can be used. There is no need to provide 54.

  Also, if a subscriber with a built-in filter is used as the IP broadcast optical terminal 14 at the subscriber's home that receives both the IP broadcast and the RF broadcast, a splitter may be provided instead of the wavelength multiplexing device 54. Also in this case, both the IP broadcast and the RF broadcast can be viewed.

  Also, in the fourth embodiment, as in the third embodiment, a part of a downstream IP broadcast signal such as a video distribution service may be multiplexed with an IP broadcast signal to reduce traffic.

  As described above, since the IP broadcast and the RF broadcast can coexist as in the fourth embodiment, it is possible to gradually shift from the RF broadcast system to the IP broadcast system.

  In the first to fourth embodiments, the configuration of the optical fiber network is a double star type, but a network topology of a star type, a ring type, or the like may be used.

  The IP broadcasting system of the present invention is suitable as a system for efficiently and stably performing IP broadcasting such as terrestrial digital broadcasting and 4K / 8K broadcasting.

10: IP broadcast apparatus 12: Optical amplifier 13, 22: Splitter 14, 44: IP broadcast optical terminal 15: IP-STB
20: IP communication device 21: OLT
23, 43: ONU
24: HGW
26, 31, 40, 53, 54: Multiplexing device 30: IP notification broadcasting device

Claims (9)

An IP broadcast system provided with an IP communication network for performing IP communication, and an IP broadcast network for performing IP broadcast independently of the IP communication network,
The IP broadcast network is
An IP broadcast device that is disposed on the center side and transmits an IP broadcast signal that is an optical signal;
An IP broadcast optical terminal arranged at each subscriber's house, receiving the IP broadcast signal from the IP broadcast device via an optical fiber network, and converting the IP broadcast signal into an IP broadcast signal as an electric signal;
An IP-STB disposed at each subscriber's house and performing IP communication with the IP broadcast optical terminal;
Has,
The IP-STB transmits information on a channel selected by a subscriber to the IP broadcast optical terminal,
The IP broadcast optical terminal extracts a signal of a selected channel from an IP broadcast signal based on channel information from the IP-STB, and transmits the signal to the IP-STB;
The IP-STB outputs an IP broadcast signal of a selected channel from the IP broadcast optical terminal;
An IP broadcast system, characterized in that: Out of the IP communication, a downstream IP communication signal of a predetermined IP communication service is multiplexed with the IP broadcast signal and transmitted from the center to each subscriber's house, and an upstream IP communication signal of the predetermined IP communication service is transmitted. Is transmitted from each subscriber's home to the center via the IP communication network,
The IP broadcast system according to claim 1, wherein:   An IP notification broadcast device for transmitting an IP notification broadcast signal for performing IP notification broadcast is provided at the center side, the IP notification broadcast signal is multiplexed with the IP notification broadcast signal and transmitted, and the IP broadcast optical terminal receives the IP notification broadcast signal. To the IP-STB, and the IP-STB outputs the received IP notification broadcast signal.   An IP radio broadcast device for transmitting an IP radio broadcast signal for performing an IP radio broadcast is provided at the center side, the IP radio broadcast signal is multiplexed with the IP broadcast signal and transmitted, and the IP broadcast optical terminal receives the received IP radio broadcast signal. The IP broadcast system according to claim 1 or 2, wherein the IP broadcast signal is transmitted to the IP-STB, and the IP-STB outputs the received IP radio broadcast signal.   The IP broadcast system according to any one of claims 1 to 4, further comprising an RF broadcast network for performing RF broadcast, wherein the RF broadcast signal is wavelength-multiplexed to the IP broadcast signal and transmitted. .   The IP broadcast system according to any one of claims 1 to 5, wherein the IP broadcast network performs only downstream IP broadcast.   7. The optical fiber network according to claim 1, wherein one amplifier and one splitter are used as one unit, and the units are combined in multiple stages and branched in a tree shape. 2. The IP broadcast system according to item 1.   8. The IP broadcast system according to claim 1, wherein the number of branches of the optical fiber network in the IP broadcast network is larger than the number of branches of the optical fiber network in the IP communication network. .   The transmission distance of the IP broadcast network is longer than the transmission distance of the IP communication network.

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