JP2000101607A - Broadcast communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a broadcast communication system capable of equally receiving multi-channel video signals anywhere. SOLUTION: Cross connect devices 102, to which plural broadcasting stations 108 are connected, are connected in the shape of a tree net by a collection system transmission line 103 composed of optical fibers and a collection network 100 is constituted. A distribution network 101, which is constituted by connecting distributors 105 in the shape of a tree net by a distribution system transmission line 104 composed of optical fibers, is connected to one cross connect device 102 of the collection network 100. Plural distribution nodes 107 are connected to the distributor 105 in the shape of a star. The distribution node 107 is connected to a subscriber network and broadcast signals transmitted from the collection network 100 are distributed to respective subscribers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a wide area broadcast communication system using a wide area communication network such as a wideband ISDN.

[0002]

2. Description of the Related Art In recent years, digitization of communication networks has been promoted on an international level. In Japan, NTT is 1NS
Practical services have already been started as Net 64 and INS Net 1500. In this service, what is conventionally connected to individual communication networks (voice communication network, facsimile communication network, data communication network) such as voice communication terminal, facsimile and data communication terminal is simply connected to the same communication network. It's getting better. The concept of such a communication network is
ISDN (Integrated Services)
Digital Network) and CC1T
This is the result of international standardization work that has been promoted mainly by T (International Telegraph and Telephone Advisory Committee). In ISDN, the upper limit of the capacity of the transmission path is 1.544 Mbps or 2.048 Mbps.
Mbps N-ISDN (Narrowband)
ISDN) and B-ISDN (Broadband ISDN), which has an upper limit of 155.52 Mbps or 622.08 Mbps and can also provide a moving image service.

[0003] N-ISDN has been put into practical use at present, and various services are provided.
Is still in the research stage, and there are few examples of specific applications.

On the other hand, the current moving image service is represented by TV broadcasting, but this service is provided mainly in the Tokyo metropolitan area, and only a part of programs provided in the metropolitan area can be viewed in rural areas. . In addition, a TV broadcast produced by a local broadcasting station can be viewed only in the local area.
Many locals working for companies in the Tokyo metropolitan area can only know their hometown by local news broadcast on the Tokyo metropolitan broadcasting station.

[0005]

As described above, in current TV broadcasting, equivalent programs are not always seen in various parts of the country, and only services that are concentrated in the Tokyo metropolitan area can be provided.

SUMMARY OF THE INVENTION The present invention has been made to address the above circumstances, and an object of the present invention is to provide a broadcast communication system capable of uniformly receiving multi-channel video anywhere.

[0007]

In order to solve the above-mentioned problems and achieve the object, the present invention uses the following means.

(1) A broadcast communication system according to the present invention includes a collection network for collecting a plurality of broadcast signals transmitted from a plurality of broadcast stations, and a subscriber connected to the collection network for accommodating one or a plurality of subscribers. A distribution network that has a plurality of distribution nodes connected to a network and transmits a plurality of broadcast signals collected by a collection network to each of the plurality of distribution nodes, wherein the distribution node has a plurality of transmitted broadcasts. Desired by the subscriber from the signal,
Alternatively, a predetermined broadcast signal is selected and distributed to subscribers.

(2) A broadcast communication system according to the present invention is the broadcast communication system described in (1) above, wherein a collection network and a distribution network divide a broadcast signal into fixed-length cells and transmit the divided signals.

(3) A broadcast communication system according to the present invention is the broadcast communication system described in the above (1), and the collection network is a tree-like network.

(4) The broadcast communication system of the present invention is the broadcast communication system described in (1) above, and the collection network is a ring network.

(5) A broadcast communication system according to the present invention is the broadcast communication system described in (1) above, and the collection network is a loop network.

(6) A broadcast communication system according to the present invention is the broadcast communication system described in (1) above, and the collection network includes a cross-connect device to which a broadcast station is connected.

(7) A broadcast communication system according to the present invention is the broadcast communication system described in (1) above, and the distribution network is a tree-like network.

(8) A broadcast communication system according to the present invention is the broadcast communication system described in the above (1), and the distribution network is a ring network.

(9) A broadcast communication system according to the present invention is the broadcast communication system described in (1) above, and the distribution network is a loop network.

(10) A broadcast communication system according to the present invention is the broadcast communication system described in (1) above, and the distribution network is a passive network.

(11) A broadcast communication system according to the present invention is the broadcast communication system described in the above (1), and the subscriber network is a tree network.

(12) A broadcast communication system according to the present invention is the broadcast communication system described in the above (1), and the subscriber network is a ring network.

(13) A broadcast communication system according to the present invention is the broadcast communication system described in the above (1), and the subscriber network is a loop network.

(14) A broadcast communication system according to the present invention is the broadcast communication system described in (1) above, and the subscriber network is a passive network.

(15) A broadcast communication system according to the present invention is the broadcast communication system described in (1) above, and the subscriber network is a star network.

(16) A broadcast communication system according to the present invention is the broadcast communication system described in (1) above, wherein the collection network and distribution network transmit digital signals, and the subscriber network transmits analog signals. , The distribution node comprises means for converting a digital signal into an analog signal.

(17) A broadcast communication system according to the present invention is the broadcast communication system described in (1) above, and the subscriber network divides a broadcast signal into cells of a fixed length and transmits them.

(18) A broadcast communication system according to the present invention is the broadcast communication system according to the above (1), wherein the subscriber network transmits a broadcast signal from the distribution node to the subscriber and transmits the broadcast signal from the subscriber. It has a bi-directional transmission function for transmitting requests to distribution nodes.

(19) The broadcast communication system according to the present invention is the broadcast communication system according to the above (1), wherein the collection network and the distribution network are the first channels for transmitting programs provided to all subscribers. And a second channel for transmitting programs selectively provided in response to requests of individual subscribers.

(20) The broadcast communication system according to the present invention is the broadcast communication system described in (19) above, wherein the requesting subscriber can receive the second channel, and the requesting subscriber can receive the second channel. Cannot receive.

(21) The broadcast communication system according to the present invention is the broadcast communication system described in (19), wherein the request is an immediate type in which a program is provided to a subscriber immediately upon request, and a request after the request. Non-immediate type, in which the provision of a program is started after a predetermined time has elapsed.

(22) The broadcast communication system according to the present invention is the broadcast communication system described in (19), wherein the same program is already present when a certain subscriber requests to provide a certain program. If the request is assigned to the second channel, no new channel is assigned to the request.

(23) The broadcast communication system according to the present invention is the broadcast communication system according to the above (19), wherein the same program is already present when a certain subscriber requests to provide a certain program. When the program is allocated to the second channel, the program is provided to the subscriber using the second channel.

(24) A broadcast communication system according to the present invention is the broadcast communication system described in (21), and notifies a subscriber of a result of availability of a channel in response to an immediate type channel request.

(25) The broadcast communication system according to the present invention is the broadcast communication system according to the above (21), wherein a channel assignment is scheduled for a non-immediate type channel request, and a result of whether or not a channel can be provided is obtained. To the subscriber.

(26) The broadcast communication system of the present invention is the broadcast communication system described in (19) above, and in the case where a request can be allocated to a channel, a fixed reservation type for guaranteeing the provision of a program immediately upon request. And a provisional reservation type that temporarily secures the provision of the program at the time of the request. If there is a request of the provisional reservation type, the reservation is canceled if there is a request of the fixed reservation type thereafter.

(27) The broadcast communication system according to the present invention is the broadcast communication system described in the above (26), and performs a reservation when a reservation of a provisional reservation type is requested and the reservation is canceled. Notify the subscribers that did so.

(28) A broadcast communication system according to the present invention is the broadcast communication system described in (1) above, wherein the broadcast station is a TV broadcast station or a production company that produces a video program provided by a program provider. including.

(29) A broadcast communication system according to the present invention is the broadcast communication system described in (1) above, and the collection network and the distribution network are optical fiber communication networks.

(30) The broadcast communication system according to the present invention is the broadcast communication system described in (1) above, wherein the distribution node is a channel selection device connected to the distribution network, a satellite broadcast reception device, A network connection device connected to the ISDN, and a channel switch for connecting a signal from the video package library to the subscriber network.

(31) A broadcast communication system according to the present invention is the broadcast communication system described in (30) above, and the video package library stores read-only optical disk devices and information obtained from B-ISDN. A rewritable optical disk device and a write-once optical disk device.

(32) A broadcast communication system according to the present invention is the broadcast communication system described in (1) above, and the subscriber network includes a CATV network and an FTTH network.

(33) A broadcast communication system according to the present invention is the broadcast communication system described in (1) above, and the collection network and distribution network perform optical wavelength division multiplexing communication.

(34) A collection network for collecting broadcast signals transmitted from a plurality of broadcasting stations, and a plurality of distribution nodes connected to the collection network and connected to a subscriber network accommodating one or more subscribers. And a distribution network for transmitting the broadcast signal collected by the collection network to each of the plurality of distribution nodes, wherein the distribution node is provided by the subscriber from the transmitted broadcast signal or is predetermined. In a broadcast communication system for selecting a broadcast signal and distributing it to subscribers, a broadcast station facility connected to a collection network and transmitting the broadcast signal.

(35) A collection network for collecting broadcast signals transmitted from a plurality of broadcast stations, and a plurality of distribution nodes connected to the collection network and connected to a subscriber network accommodating one or more subscribers. And a distribution network for transmitting the broadcast signal collected by the collection network to each of the plurality of distribution nodes, wherein the distribution node is provided by the subscriber from the transmitted broadcast signal or is predetermined. In a broadcast communication system for selecting a broadcast signal and distributing it to subscribers, an in-home device connected to the subscriber network and receiving the distributed broadcast signal.

(36) A collection network for collecting broadcast signals transmitted from a plurality of broadcast stations, wherein the collection network is connected to a distribution network for transmitting the collected plurality of broadcast signals, and the distribution network is connected to a subscriber network. Is connected to a distribution node for selecting and transmitting a predetermined broadcast signal from the distribution network in accordance with the request of the distribution node. The distribution node accommodates one or a plurality of subscribers and is selected by the distribution node. Collection network connected to the subscriber network that distributes

(37) A distribution network connected to a collection network for collecting broadcast signals transmitted from a plurality of broadcast stations and transmitting a plurality of broadcast signals, wherein the distribution network responds to a request from a subscriber. Alternatively, the distribution node is connected to a distribution node for selecting and transmitting a predetermined broadcast signal from a distribution network, and the distribution node accommodates one or more subscribers and distributes the broadcast signal selected by the distribution node. A distribution network connected to the network.

(38) It is connected to a distribution network for transmitting a plurality of broadcast signals, which is connected to a collection network for collecting broadcast signals transmitted from a plurality of broadcast stations, and receives a request from a subscriber or a predetermined predetermined signal. A distribution node for selecting and transmitting a broadcast signal from a distribution network, wherein the distribution node accommodates one or more subscribers and is connected to a subscriber network that distributes the broadcast signal selected by the distribution node. .

(39) In response to a request from a subscriber connected to a distribution network for transmitting a plurality of broadcast signals connected to a collection network for collecting broadcast signals transmitted from a plurality of broadcast stations,
Alternatively, a subscriber network connected to a distribution node for selecting and transmitting a predetermined broadcast signal from the distribution network and accommodating one or more subscribers, wherein the subscriber network is selected by the distribution node. Subscriber network that distributes broadcast signals.

According to the present invention, broadcast signals transmitted from a plurality of broadcasting stations are collectively collected by a collection network, and the collected broadcast signals are distributed to all distribution nodes via the distribution network. Then, the broadcast signal desired by the subscriber is selected and transmitted to the subscriber network, so that the subscriber connected to the distribution node receives all broadcast signals collected by the collection network equally. be able to.

[0048]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a broadcast communication system according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a first embodiment of the broadcast communication system according to the present invention. Here, the contents of the video information include TV broadcasting programs currently provided by private broadcasting stations regardless of public broadcasting stations, metropolitan areas, and regions, remote reception of lectures at universities, private supplementary schools, etc. There are TV broadcasts, corporate broadcasts, and overseas broadcasts re-received by local governments. A number of broadcast stations 108 that send out these programs
Are connected to one collection network 100. The collection transmission line 103 realized by the optical fiber is the cross-connect device 1
02 are connected in a tree shape, and a collection network 100 is configured by a tree-shaped communication network. The broadcasting stations 108 scattered in various places are connected to the collection transmission line 103 via the nearest cross-connect device 102. Here, the broadcasting station 108
Is an information provider, including a video production company. Further, the contents of the program include not only video but also data information such as teletext. The capacity of the collection transmission line 103 can be arbitrarily selected.
ps.

When digitally transmitting the current NTSC TV broadcast, it is said that sufficient image quality can be obtained if the transmission capacity is about 10 Mbps. Therefore, according to this, 1000 channels can be secured as TV broadcast channels on the 10 Gbps transmission path. Currently, the number of Japanese TV stations is less than 100 nationwide. Therefore, in this embodiment in which 1000 channels can be used, it can be said that the present embodiment has a sufficient channel capacity to accommodate all the broadcasting stations and to provide specialized broadcasting such as lectures, hobbies, and entertainments at universities and the like. Also, C
In the United States where ATV has been developed, a service of 150 channels has been put to practical use, but the present embodiment realizes a video service of a channel number far exceeding that.

On the other hand, in terms of hardware, practical use of 5 Gbps transmission has already been embodied with a submarine cable extending over 9000 km across the Pacific Ocean. Therefore, even if a collection system covering the whole of Japan targeted by the present invention is provided,
Since about 000 to 4000 km can be sufficiently covered, the construction of an optical transmission line of 10 Gbps can be easily realized.

Broadcast program information created by a broadcast station 108 or an information provider (not shown in FIG. 1, but considered to be a synonym of the broadcast station 108) in each location is transmitted from an appropriate cross-connect device 102 from an economic viewpoint. Is put on the collection system transmission line 103 which is deployed nationwide. As described above, the collection transmission line 103 always transmits program information from all the broadcasting stations 108. The cross-connect device 102 is a connection device in which the outgoing line is uniquely determined with respect to the incoming line, and has an advantage that it can be realized with simple hardware as compared with a general exchange.

Although not shown, the collection network 100 may be constituted by a hierarchical communication network.

On the other hand, any one of the distribution transmission lines 104 of the distribution network 101 that directly provides information to each subscriber is connected to any one of the cross-connect devices 102 of the collection network 100. The distribution transmission line 104 is also formed of an optical fiber. The distribution network 101 is also configured by a tree-shaped communication network. The distribution system transmission lines 104 are connected in a tree shape using a distributor 105. An amplifier 106 for compensating signal attenuation is connected between the distributors 105 as needed. A plurality of distribution nodes 107 are connected to the distributor 105. Thus, all the program information transmitted through the collection network 100 is always delivered to the distribution node 107.

As described above, by dividing the network between the collection system and the distribution system, the distribution network can be a passive network, and the cost of network construction can be reduced.

Note that the collection system transmission line 103 and the broadcasting station 108
Connection with the cross-connect device 10 having no exchange function
2, but an exchange having an exchange function may be used in place of some or all of the cross-connect devices.

FIG. 2 is a diagram showing a configuration of an embodiment of a broadcast communication system according to the present invention when a ring or loop communication network is used as a main part of a collection network and a distribution network. A distribution network 201 is connected to a ring-shaped or loop-shaped main network 200 which also serves as a collection network and a distribution network. A network node device 202 is connected in a ring shape or a loop shape by a transmission line 203 composed of an optical fiber serving as a collection system and a distribution system. In FIG. 1, one cross-connect device 102
Although two broadcasting stations 108 are connected, in FIG. 2 (a large number of broadcasting stations 208 are connected to one network node device 202. The configuration of the distribution network 201 is the same as that of the distribution network 101 of FIG. 1). Naturally, the loopback function and the system switching function are taken into consideration as a measure against a failure.

The difference between the ring communication network and the loop communication network is that the network node device 202 has an equal distribution function in the ring communication network, while the network node device in the loop communication network. One of the points 202 is a master station.

FIG. 3 is a diagram showing a configuration example of the distribution node 207 included in the distribution network of the broadcast communication system shown in FIGS. The distribution system transmission line 204 is the channel selection device 3
03 is connected to the channel switching apparatus 301. A satellite antenna 312 for receiving radio waves from the broadcasting satellite BS / communication satellite CS is connected to the channel switching device 301 via the satellite broadcasting receiving device 302. A public network different from the system of the present invention, for example, a B-ISDN
Is connected to the channel switching apparatus 301 via the. Video signal converter 305, Video package library 30
6. Service control device 30 to which charging device 309 is connected
8 is also connected to the channel switching device 301. Subscriber network 3
10 is connected to the channel switching device 301 via the subscriber network connection device 307.

Here, the operation of the distribution node 207 configured as shown in FIG. 3 will be described. Channel switching device 301
Is a satellite broadcast receiver 302, a channel selector 303
And a switching function of distributing each program (channel) supplied from the network connection device 304 to subscribers who need it. The satellite broadcast receiving apparatus 302 is a broadcasting satellite or communication satellite receiving apparatus which is already in practical use, and can provide these video programs to the subscriber network via the channel switching apparatus 301 as needed. It has become. The channel selection device 303 and the network connection device 304 receive programs from the distribution network and the B-ISDN network, respectively. There is a weak point that it is difficult or impossible to provide. Therefore, the reason is that the satellite broadcast receiving apparatus 302 considers backup in such a case.

The channel selection device 303 is the distribution system transmission line 2
This is a device which is connected to the channel switching device 301 and selects a channel required in the subscriber network from all the transmitted channels on the distribution network 101 of about 1000 channels under the control of the service control device 308 and transfers it to the channel switching device 301.
The network connection device 304 is an interface device with the B-ISDN, and is a device for taking in a video service of the B-ISDN, which is currently under various studies.

The subscriber network connection device 307 is an interface device with the subscriber network 310 for providing information to each subscriber, and the number of subscribers accommodated in each device 307 is not particularly limited, but is used here. Almost 50 subscribers. Reducing the number of subscribers in this way aims at eliminating the need to insert an amplifier in the subscriber network 310.
Further, if the subscriber network connection device 307 is equipped with, for example, about 10 per distribution node, each distribution node has about 5 nodes.
00 subscribers. This is intended to improve cost performance by downsizing based on the so-called Grosh's law in computer performance evaluation. Video signal converter 305
Transmits digital video signals from the channel selection device 303 and the network connection device 304 to the subscriber network 310 if necessary.
This is a device for converting into an analog video signal that can be carried on a computer. Also, the video signal conversion device 305
It has a plurality of conversion functions so that different programs can be simultaneously provided to many subscribers. As described above, the channel switching device 301 has a hybrid switching function for switching and controlling both digital signals and analog signals.

The video package library 306 is a kind of video disk device that provides popular video package software frequently accessed by subscribers. By providing such a storage device in the distribution node, it is possible to reduce the amount of traffic with the distribution network and the B-ISDN network.

The service control unit 308 judges a request from the subscriber and issues a command to the channel switching unit 301, the channel selection unit 303, the network connection unit 304 and the like to add the program requested by the subscriber to the corresponding subscription. It has a role to provide to the network. The billing device 309 is a device for billing according to each subscriber's request.

FIG. 4 shows a video package library 306.
FIG. It comprises three types of optical disk devices: a read-only optical disk device 401, a write-once optical disk device 402, and a rewritable optical disk device 403. The read-only optical disc device 401 is for recording fixed information with high access frequency, and the write-once optical disc device 402 is for recording frequently accessed information among rewritable optical disc devices. Rewritable optical disk device 403 is a B-ISD
It can be used for storing information obtained via N. Since each optical disk device requires a considerable memory capacity, a multiple-type optical disk device having an autochanger mechanism and capable of simultaneously accessing a plurality of optical disks is appropriate.

FIG. 5 shows an example of an information transfer format of a collection network and a distribution network up to a distribution node in the present broadcast communication system. This format is B-ISDN
ATM (Asynchronous)
Transfer Mode). The information is decomposed every 48 octets (1 octet = 8 bits) and transferred with a 48 octet information and a 5-octet cell header added. The content of the cell header is VP1 (Virtual1 Path).
Identifier) and VC1 (Virtual)
Information indicating a destination called a Channel Identifier, information indicating a cell type called PT (PayloadType), information indicating a priority at the time of discarding a cell called P (Priority), and an HEC (Header E) for checking a transmission error in a cell header portion.
rr Check). The function of each information is well known in the CCITT recommendation of B-ISDN and the TTC standard, and the detailed description is omitted. Since B-ISDN covers moving picture services, it is clear that a similar transfer format can be used in the present invention.

FIGS. 6A and 6B are diagrams showing a state of cell transfer in the ATM. FIG. 6A shows a case in which a cell containing information and a vacant cell without information are transferred without any gap on the transmission path. On the other hand, FIG.
1, which indicates a method of transferring cells by pushing cells into a synchronous format. At present, research on practical use is being promoted by the method shown in FIG. 6B, and the present invention also allows cell transfer by this method.
In addition, SOH (Section 0 ver Head)
Is an information area for exchanging maintenance / operation information between opposing devices.

FIG. 7 shows an example of the subscriber network 310 shown in FIG. Here, a so-called FTTH (Fiber To The Home) using a tree-shaped CATV network 714 made of a coaxial cable or an optical fiber and an optical fiber is used.
e) Show network 715. The CATV network 714 is the distributor 70
2. Consisting of a branching device 703 and a customer premises device 710,
The subscriber premises equipment 710 is a network termination equipment 711, a video terminal 7
It consists of 12. The FTTH network 715 includes a distributor 713 and a subscriber premises device 710. The subscriber network is not limited to the tree network, but may be a loop network, a ring network, or a star network.

FIG. 8 shows an example of the usage status of the frequency band in the subscriber network. 10 MHz to 50 MHz is a band used as an upper re-channel, and 70 MHz or more is a band used as a lower re-channel. As an upper channel,
Because it is used to transfer control information such as a request for a program (channel) that the user wants to watch, a 40 MHz band is not required. 40 MHz is allocated so that the On the other hand, the lower channel is a channel that provides a video signal to each subscriber, and thus requires a larger band. In current TV broadcasting, 6
Since channels are allocated for each MHz, if there are 50 channels, 6 MHz × 50 channels = 300 MHz
A certain bandwidth is required. In this case, the upper limit of the lower re-channel is 370 MHz.

Next, a channel request from a subscriber will be described. FIG. 9 is a diagram illustrating an example of a method of using a channel. An example is shown in which the total number of provided channels is 50, and 10 channels are provided as common channels that can be viewed by anyone, and the remaining 40 demand channels provided in response to requests from subscribers are configured. The common channel is, for example, a channel that can be viewed within a basic fee, and the demand channel is a channel with a low rating, but may be a channel to which a fee is added similarly to a so-called pay TV. Among the channels, there are a channel in which a program broadcasted in real time via a collection network and a distribution network is transmitted, and a channel in which reproduction information of a desired video package selected from a video package device is transmitted. Therefore, it is necessary to add a function to the demand channel so that only the subscriber who has requested the channel can view the data, and the demand channel cannot be viewed by the subscriber who has not requested the channel. This technique has already been put into practical use, and there is a method of scrambling a video signal, for example, and performing descrambling processing on the subscriber premises equipment side.

In the channel request, there are a case where the user wants to view the program immediately after issuing the request and a case where a request for a program to be broadcast later is reserved.

Therefore, it is necessary to have two types of channel control systems, an immediate type in which a channel is assigned immediately upon receiving a request and a non-immediate type in which a channel is assigned after a predetermined time has elapsed.

Further, although the bandwidth of the lower re-channel is wide, it is limited and must be used effectively. Therefore,
In the demand channel assignment, if another subscriber requests the same program in a situation where the program requested by one subscriber is already distributed to the subscriber network through a certain channel, It is also necessary that subscribers who request the same program without allocating a channel can access through the same channel to effectively use a limited number of channels.

It is important on the human interface to notify the subscriber about the availability of channel assignment (program provision) for both immediate type channel requests and non-immediate type channel requests. It is.

Further, in response to the above channel request, there is a fixed reservation type for guaranteeing channel reservation at the time of request when a channel can be provided, and a provisional reservation type for temporarily securing a channel. In some cases, the reservation may be canceled if there is a request for a fixed reservation type and the number of channels becomes insufficient. However, it is also considered necessary to provide a service in which the provisional reservation type sets a lower usage fee than the fixed reservation type. However, when the reservation is of a provisional reservation type and the reservation is canceled as described above, it may be necessary to notify the reservation person that the reservation has been canceled.

In these service specifications, various measures have been devised for satisfying the degree of demand for a subscriber channel in a limited channel.

FIG. 10 is a diagram for explaining optical wavelength multiplexing in optical fibers in a collection network and a distribution network. As is apparent from the figure, the wavelength is generally around 1.3 μm and 1.55 μm.
It is known that the attenuation of light near m is small, and light emitting diodes of these wavelengths are selected for long-distance optical transmission. In addition, optical wavelength multiplexing transmission utilizing the difference in wavelength is possible, and when this is used, low-speed information transmission of voice, data, etc. using a 1.3 μm optical signal (two-way transmission).
In addition, multiplex transmission in which high-speed information transfer of video signals and the like (one direction) using 1.55 μm optical signals can be realized.

Next, an example of an application realized by using the broadcast communication system according to the present invention will be described. First, it is possible to easily implement a nationwide cram school service. Referring to FIG. 1, a broadcasting station 108 captures an image of a lecture at a cram school or the like, a video signal is collectively collected by a collection network 100, and further distributed by a distribution network 101 to nodes distributed throughout the country. It is transmitted to 107. Distribution node 10
7 to the video terminal 712 (FIG. 7) of each home using a subscriber network, for example, a demand channel, so that it is possible to receive the cram school service while staying at homes nationwide. Of course, it is clear that it is also possible to receive at a cram school established in various places instead of at home. In addition to the cram school service, various educational broadcasts such as university courses and foreign language courses can be realized. In addition, it is possible to easily provide broadcasts currently produced by TV broadcast stations (regardless of key stations and local stations) nationwide throughout the country. Again,
The broadcast station shown in FIG. 1 corresponds to a broadcast station nationwide, and the video produced here can be received at homes nationwide in the same manner as the above-mentioned application by placing it on a collection network via a cross-connect device. In addition, sports, movies,
It is clear from the above description that national services of specialized channels such as hobbies and economics, public relations of governments and local governments, and broadcasting of congressional broadcasting or overseas broadcasting in Japan can be easily realized.

Although the example of the current NTSC system has been described as a TV broadcast, the HDTV which is currently being put into practical use has been described.
It is clear that even in the case of high definition television broadcasting such as (High Definition TV), the present invention can be easily implemented only by allocating the transmission capacity per channel about five times larger. Also, an example is shown in which the video package library is connected to the distribution node. However, for those with very low access frequency, a plurality of distribution nodes or one video package library may be provided for the entirety.
-It is also possible to transmit via ISDN or collection and distribution networks.

[0080]

As described in detail above, according to the present invention, a super multi-channel broadcast signal can be received all over the country, and a wide area multi-channel broadcast service not available in conventional TV broadcasting and CATV can be realized. Effect can be expected.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of a broadcast communication system according to the present invention.

FIG. 2 is a block diagram of the first embodiment when a collection network is a ring or loop network.

FIG. 3 is a block diagram illustrating an example of a distribution node in the distribution network according to the first embodiment.

FIG. 4 is a block diagram showing an example of a video package library in the distribution node of FIG. 3;

FIG. 5 is a diagram showing an example of an information transfer format in the broadcast communication system.

FIG. 6 is a diagram showing an example of a cell transfer format in the broadcasting system.

FIG. 7 is a block diagram showing an example of the subscriber network shown in FIG. 3;

FIG. 8 is a diagram illustrating an example of a usage state of a frequency band in a subscriber network.

FIG. 9 is a diagram showing an example of using channels in the present invention.

FIG. 10 is a characteristic diagram for explaining optical wavelength multiplexing in a communication network of the present system.

[Description of Signs] 100: Collection network 101: Distribution network 102: Cross-connect device 103: Collection system transmission line 104: Distribution system transmission line 105: Distributor 106: Amplifier 107: Distribution node 108: Broadcasting station

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) H04N 7/173 H04L 11/18 (72) Inventor Toshiyuki Nakaji 4-11-5-602 Sanno, Ota-ku, Tokyo (72) Inventor Yasushi Kamiyama 1-496-12 Imai, Ome City, Tokyo

Claims (1)

[Claims] 1. A collection network for collecting a plurality of broadcast signals transmitted from a plurality of broadcast stations, and a plurality of distribution networks connected to the collection network and connected to a subscriber network accommodating one or a plurality of subscribers. A distribution network for transmitting the plurality of broadcast signals collected by the collection network to each of the plurality of distribution nodes, wherein the distribution node subscribes to the plurality of broadcast signals transmitted from the plurality of distribution nodes. A broadcast communication system characterized in that a broadcast signal desired or predetermined by a user is selected and distributed to subscribers.