JPH01238392A - Catv distributing system - Google Patents

Abstract

PURPOSE:To perform both of services of a digital line system and a digital CATV so as to reduce the cost of the title system by sending CATV information by utilizing the subscriber line of a wide-band exchange system and subscriber lies among remote equipment. CONSTITUTION:A station which performs exchanging operations receives the supply of CATV program sources from a CATV center 10 and transmits the CATV programs to remote equipment RE by putting the programs on the slots of subscriber's main lines L. At the remote equipment RE, regarding video telephone the part of the channel from the station CO to its own equipment is dropped from the subscriber's main line loop L and regarding CATV all channels are fetched to its own equipment and, at the same time, sent to another equipment. Sending of CATV signals to subscribers terminals 14A, 14B... is performed in response to requests of subscribers. The requests are received by a signal processor SGU and switching of the multidistributing paths of line concentrating/line separating stages S1 and S2 is performed in accordance with the requests. Transmission of the CATV information between the station CO and each remote equipment RE is performed by an optical fiber which is separate from the subscriber's main line loop L.

Description

[Detailed Description of the Invention] [Summary] Regarding a CATV distribution system using a broadband switching system - The transmission path between the remote device of the broadband switching system and the subscriber is also used for CATV television signal transmission, and the CATV system is Aiming at low cost, it connects the exchange center and multiple remote devices concentrating/separating lines using time-slotted optical fibers, and connects each subscriber to each remote device using time-slotted optical fibers. Using a broadband switching system, multiple channels of CATV signals are transmitted from the center to each of the remote devices, and the remote devices transmit the CATV signals of the channel requested by the subscriber to one of the time slots not used for videophone calls, etc. The system is configured to send the information to the subscriber on the same basis.

[Industrial application field]

The present invention relates to a CATV distribution system using a broadband switching system.

CATV connects a center and subscriber's homes through transmission lines, and transmits various television programs from the center to each subscriber's home.

In addition, circuit switching equipment connects subscriber's homes via a transmission line through a central office (exchange), and allows the subscriber's homes connected through the exchange to communicate with each other.

In order to install a videophone and CATV at a subscriber's home, it is necessary to run transmission lines for the videophone and CATV to the subscriber's home, but if they can be shared, only one transmission line is required. The present invention transmits CATV using a broadband circuit switching system,
This relates to a method that requires only one transmission path.

[Conventional technology]

FIG. 4 shows an example of the configuration of caTVt and til. 10 is center equipment, which includes UHF/VHF reception equipment 10a, satellite reception equipment 10b, production studio IQc, and transmission equipment 10.
d. 12 is a transmission equipment, which includes a signal transmission line 12a1, a relay amplifier 12b1, and a tap-off 12C;
is subscriber equipment, which includes a television receiver 14a and the like. The configuration of the transmission line connecting the center equipment and each subscriber is shown in Figure 4).
There is a dendritic shape shown in the figure, a star shape shown in the same figure (C), etc.

However, the dendritic form of (bl) is widely used in CATV networks.

Currently, analog signals are the mainstream for CATV system transmission signals, and the number of program channels supplied from the center reaches 100 channels. In line with trends such as digitization and optical fiber transmission lines, it is conceivable to convert conventional analog CATV using coaxial cables to optical digital CATV, but since it requires a transmission line of 150 Mbps per program channel, Dendritic shape of bl, Fig. 4 (
Both the star shape of C1 and the large capacity transmission line (150MX 1
00ch) must be installed at the subscriber's home, which increases costs.

On the other hand, in the telephone switching system as well, a broadband switching system that uses optical fibers to connect to subscriber's homes is being considered. An example thereof is shown in FIG. L is a subscriber trunk loop composed of optical cables, CO is a station for switching, RE is a remote device for concentrating and separating lines, and 14A, 14B, . . . are video telephone terminals, etc.

Subscriber distribution transmission line connecting subscriber terminals and remote equipment! Also 60
A 0 Mbps optical fiber is condensed/separated at a remote device RE and connected to a time-slotted 2°4 Gbps subscriber trunk loop L. The remote equipment RE includes concentrator/separation stages SI and S2, a signal processing unit SGU, and a call processing unit CPU, and the office CO includes an exchange SW and a call processing unit C.
Equipped with PU.

[Problem to be solved by the invention]

In a broadband switching system that uses optical fiber to reach subscribers' homes, there is still plenty of transmission capacity even if telephone calls are replaced by video calls.

It is an object of the present invention to provide a CATV system at low cost by using a transmission line between a remote device of a broadband switching system and a subscriber terminal for CATV television signal transmission.

[Means to solve the problem]

As shown in FIG. 1, in the present invention, the remote device RE is connected to a CATV
A signal 20 of the requested channel is sent from the center equipment, and a signal of the requested channel is sent from this remote device to each subscriber terminal 14A, 14B, .

This remote equipment RE concentrates/separates the m channels on the subscriber side and the subscriber trunk loop L (lIIn channels. S is a space switch therefor, and T is a time switch.

Optical fiber, time slot type subscriber distribution transmission line
In this example, the transmission capacity of is 600 Mbps, and since 150 Mbps is sufficient for videophone information transmission, each subscriber distribution transmission line has a transmission capacity of 4 channels. Therefore, the first channel is for videophone, the second channel is for PC,
A third option is attached to a digital terminal such as a fax machine. The fourth channel can be assigned to each CATV channel (2 channels), etc.

In this example, the CATV information sent from the remote device REHecenter is assumed to have 30 channels, and the CATV signal of the specified channel is sent from the subscriber terminal to the subscriber terminal via the space switch S and the time switch T. In videophone, one subscriber terminal is connected to one subscriber terminal, that is, a one-to-l connection is made, but in CATV, since multiple subscribers may request the same channel, it is a one-to-n connection. The remote device RE makes a one-to-one connection to this telephone and a one-to-n connection to the CATV.

[Effect]

With this configuration, each subscriber can remotely request transmission of CATV information and information on which channel (program) he/she desires by operating a videophone terminal (not shown) or an input device provided on the television receiver. When the information is sent to the device RE, the remote device sends information on the desired channel to the subscriber terminal on the CATV channel. In the illustrated example, subscriber terminal 14A requests the #l channel and subscriber terminal 1
Since 4J requested channel #3, in this example, channel #1 is sent to the subscriber CATV information channel, which is the third channel. #
It transmits 3 channels of CATV information.

Each subscriber can request up to two channels (programs) in this example, independent of videophones and digital terminals.
You can watch two types of CATV broadcasts at the same time. CA by using the surplus transmission capacity of the subscriber distribution transmission line l.
Since it is broadcast on TV, it is possible to use a different fee structure from that for telephone calls. Of course, there is no need to run a transmission line to each subscriber's home independently of the videophone for CATV, and it is possible to use low-cost CATV.
It becomes possible to construct TV broadcasting equipment.

〔Example〕

2 and 3 show the first embodiment of the present invention. A second example is shown.

As is the case throughout, the same parts are given the same reference numerals. The station CO that performs the exchange is the CATV center 10.
It receives a CATV program source from the subscriber trunk loop L and transmits it to the remote equipment RE in a slot of the subscriber trunk loop L. The remote device RE drops only the channel portion from the station CO to its own device for videophone calls from the subscriber trunk loop L, and for CATV it takes in all channels (30 channels in this example) to its own device and transfers them to other devices. Send it towards the device. CATV signal subscriber terminals 14A, 14B.

. . . is performed in response to a request from a subscriber.

This request is received by the signal processing unit SGU, and the multi-distribution paths of the concentrator/separator stages 31 and 32 are switched in accordance with the request. The transmission of CATV information between stations CO1 and remote equipment RE may take place by means of optical fibers separate from the subscriber trunk loop L.

In FIG. 2, the subscriber trunk loop L connecting the station CO and the remote equipment RE is a loop, but it may also be in the form of a star, an example of which is shown in FIG. Note that time slot method loop wiring is physically a loop, but
Logically, it is star-shaped. In the case of a star shape, the distance between the remote devices REs may be shorter. In this case, the CATV optical fiber La is connected to the station C as shown in the figure.
It is preferable to connect the remote devices RE without passing it through. At each remote device, CATV transmission line La brancher 3
All channels are branched at 0, and upon request from the subscriber, CATV information of the designated channel is sent out via the concentrator/separator stage.

〔Effect of the invention〕

As is clear from the above explanation, in the present invention, since CATV information is sent using subscriber lines between subscribers of a broadband switching system and remote devices, digital line-based services and digital line-based services are distributed to the same subscriber. This can be done through a transmission line, and the cost of equipment can be reduced.

In addition, since all source programs are sent from the center to remote devices, subscribers can select CATV channels in the same way as before.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention, and FIGS. 2 and 3 are diagrams explaining the principle of the present invention. FIG. 4 is an explanatory diagram of a conventional CATV system, and FIG. 5 is an explanatory diagram of a broadband switching system. In Figures 1 and 2, 10 is the center, 14A, 14B, etc.
. . . is the subscriber, CO is the station that performs the exchange, RE is the remote device that performs line concentration/separation, L is the optical fiber that connects the station and the remote device, and l is the optical fiber that connects the subscriber terminal and the remote device. .

Claims (1)

[Claims] 1. A central office (CO) that performs switching and a plurality of remote equipment (RE) that performs line concentration/separation are connected by a time slot type optical fiber (L), and each remote equipment is connected to each subscriber (14A). , 14B
,...) to a time slot type optical fiber (
Using the broadband switching system connected in step 1), multiple channels of CATV signals are transmitted from the center to each of the remote devices, and the remote devices do not use the CATV signals of the channels requested by the subscriber for videophone calls, etc. A CATV distribution system characterized by transmitting data to the subscriber in one of the time slots.