JP2003319354A - Communication system and network employing existing radio disturbance eliminating facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system and a network employing an existing radio disturbance eliminating facility capable of realizing needs of transmitting a television signal and an access or the like to the high speed Internet by using the existing radio disturbance eliminating facility adapted to a radio wave disturbance caused by a land form of a mountainous region or the like. <P>SOLUTION: A single direction amplifier placed between installed cables for the existing radio disturbance eliminating facility to stably receive a broadcast radio wave and comprising the cables, the single direction amplifier and a protector is replaced with a two-way amplifier, the protector placed at each house is replaced with a two-way protector, and the existing coaxial cable and a support fixture for the coaxial cable are used as they are for two-way communication. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an existing facility which enables two-way communication such as the Internet by utilizing a radio wave obstacle elimination facility which is a cable broadcasting facility for eliminating radio wave obstacles of terrestrial television broadcasting due to topography and buildings. The present invention relates to a communication system and a network using the radio wave interference elimination facility.

[0002]

2. Description of the Related Art Conventionally, a large number of radio wave obstruction elimination facilities have been installed in order to eliminate radio wave obstruction in an area where terrestrial television broadcasting cannot be normally received due to topography, buildings and the like. Of these, most of the radio wave obstruction elimination facilities for eliminating radio wave obstruction due to natural terrain such as mountainous areas are scattered in rural depopulated areas.

FIG. 6 is a diagram showing the structure of a radio wave obstruction elimination facility for coping with radio wave obstruction caused by the terrain such as mountainous areas. As shown in FIG. 6, a common antenna 33 for reception is installed on the top of the mountain, and the radio waves received by the common antenna 33 are distributed from the broadcast receiving / transmitting device 35 to each house by a coaxial cable 30 as a transmission path arranged in a tree shape. Television signals are distributed through the protector 32 installed. Further, the coaxial cable 30 serving as a transmission line is provided with an amplifier for each fixed length of installation.

The amplifier is for compensating the signal attenuated by the transmission through the coaxial cable 30. The amplifier uses the unidirectional amplifier 31 as shown in FIG. 6 because the signal transmission direction is only downstream. The unidirectional amplifier 31 has a capability of compensating for a frequency band of 222 MHz capable of covering the band of 12 channels of television. The television signal transmitted by the coaxial cable 30 is transmitted to the protector 32 installed in each house.
And is input to the image receiver 34 through. The conventional radio interference elimination facility is capable of signal transmission in only one direction (downlink).

[0005]

In recent years, needs for connecting to high-speed Internet, increasing the number of broadcasting channels, receiving terrestrial digital broadcasting, etc. are increasing. For this reason,
There is a strong demand in various places for wide band transmission and bidirectional communication means. However, the area having radio wave interference elimination facilities due to natural terrain such as mountains overlaps with the area that is depopulating, and the widening of communication means is not progressing as expected. To realize the above-mentioned needs in mountainous areas and areas where population is depopulating,
New equipment must be installed, and construction of equipment requires a large amount of investment. Although the Internet can be realized by using a telephone line, it is not suitable for high-speed Internet using a telephone line such as ADSL because it is far from a telephone station in a mountainous area or a depopulated area. For this reason, services such as high-speed internet could not be provided in mountainous areas and depopulated areas.

When a new facility is constructed, the coaxial cable that has been laid is no longer necessary, but the disposal of the removed coaxial cable also entails enormous cost. difficult.

In view of the above, the present invention uses an existing radio wave obstruction elimination facility to realize a need for a multi-channel television signal connection and high-speed Internet connection at a low cost. An object of the present invention is to provide a communication system and a network using the.

[0008]

A communication system using an existing radio wave disturbance elimination facility of the present invention is a laid coaxial cable,
Unidirectional amplifier, in the existing radio interference elimination facility for stably receiving broadcast radio waves consisting of protectors, replace the unidirectional amplifier arranged between the laid coaxial cables to a broadband bidirectional amplifier, The protector arranged in each door is replaced with a bidirectional protector to enable bidirectional communication.

Further, in the bidirectional amplifier of the communication system using the existing radio wave disturbance elimination facility of the present invention, the attenuation amount of the laid coaxial cable is made equal to the attenuation compensation amount of the unidirectional amplifier. Laying coaxial cables are arranged at regular intervals.

Further, the bidirectional communication of the communication system using the existing radio wave obstacle elimination facility of the present invention is for connecting to the Internet.

Further, in the network using the existing radio wave disturbance elimination facility of the present invention, the unidirectional amplifier arranged between the laying coaxial cables of the existing radio wave obstacle elimination facility is replaced with a bidirectional amplifier and is arranged in each door. In the existing radio interference elimination facility that enables bidirectional communication by replacing the protector with a bidirectional protector, connect the existing radio interference elimination facilities that enable the bidirectional communication with an optical cable. To form a wide area network.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a communication system and a network using an existing radio wave disturbance elimination facility according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a communication system using an existing radio disturbance elimination facility according to the present invention, FIG. 2 is a diagram showing a configuration of a bidirectional amplifier in the existing radio disturbance elimination facility according to the present invention, and FIG.
FIG. 4 is a diagram showing amplification characteristics of a signal level with respect to a basic span of a coaxial cable in a 770 MHz bidirectional amplifier and a 222 MHz unidirectional amplifier, and FIG. 4 is a laying distance of a coaxial cable in a 770 MHz bidirectional amplifier and a 222 MHz unidirectional amplifier. 5 is a diagram showing the amplification characteristic of the signal level for FIG. 5, and FIG. 5 is a diagram showing the configuration of a network in which existing radio wave obstruction elimination facilities capable of bidirectional communication are connected by optical cables.

As shown in FIG. 1, a communication system using an existing radio wave obstruction elimination facility according to the present invention is a multi-channel broadcast for delivering a radio signal received by an antenna 9 to each house through a coaxial cable 30. The receiving / transmitting device 8 and the WAN (Wide Ar) which is the Internet.
The signal of the modem terminating device 6 for connecting to the ea Network 21 and the signals of the multi-channel broadcast receiving / transmitting device 8 and the modem terminating device 6 are combined and distributed, and the upstream signal from the coaxial cable 30 is also combined with the modem terminating device. 6, the mixing / distributing device 7, the coaxial cable 30 for transmitting the signal from the mixing / distributing device 7, the bidirectional amplifier 10 arranged at every constant distance of the coaxial cable 30, and the bidirectional installed in each door. It consists of a protector 12.

The branch to each house is a coaxial cable 30.
This is done by tap-off (not shown) provided above. Coaxial cable 30 for tap-in to pull-in
Then, the signal is supplied to the home terminal 14 and the cable modem 15 through the two-way security device 12 installed in each door. A television signal is output from the home terminal 14 to the receiver 34. Also, the cable modem 15 is P
PC connected to C (personal computer) 17
Input / output of data to / from 17.

As shown in FIG. 1, the head end 5 comprises a multi-channel broadcast receiving / transmitting device 8, a modem terminating device 6 and a mixing / distributing device 7.

The multi-channel broadcast receiving / transmitting device 8 transmits the VHF and UHF band radio waves received by the antenna 9 and the satellite and digital broadcast waves as television signals to the coaxial cable 30. It is also configured to be able to supply independently produced programs and the like.

A television signal from the multi-channel broadcast receiving / transmitting device 8 is sent from the mixing / distributing device 7 to the coaxial cable 3.
Output to 0, the bidirectional amplifier 10 amplifies the television signal, and the tap-off installed on the coaxial cable 30 passes through the bidirectional protector 12 to the home terminal 14
And is output from the home terminal 14 to the image receiver 34.

The modem terminating device 6 is for connecting to the WAN 21, which is the Internet, and provides the PC 17 installed in each door with the Internet connection.

A signal for requesting connection to the Internet from the PC 17 is transmitted from the cable modem 15 through the bidirectional security device 12 to the coaxial cable 30 for pulling in. The signal transmitted to the coaxial cable 30 is amplified by the bidirectional amplifier 10 and input to the mixing / distributing device 7 of the headend 5, and is connected to the Internet from the modem terminating device 6 by the WAN 21. When the connection with the Internet is established, the address and the downlink data from the modem terminating device 6 are transmitted from the mixing / distributing device 7 to the coaxial cable 30, and pass through the bidirectional amplifier 10 for bidirectional security. It is output to the cable modem 15 through the device 12.
An address is assigned to the cable modem 15, and only when the addresses match, the cable modem 15
Is designed to receive data.

As the coaxial cable 30 of the communication system using the radio wave obstruction elimination facility, an existing radio wave obstruction elimination facility is used. Further, the unidirectional amplifier 31 (shown in FIG. 6) which is conventionally installed is replaced with the bidirectional amplifier 10, and the protector 32 (shown in FIG. 6) installed in each door is replaced with the bidirectional protector 12. To do. When the number of broadcast channels is increased, the common antenna 33 (shown in FIG. 6) and the broadcast receiving / transmitting device 35 (shown in FIG. 6) are replaced with the antenna 9 and the multi-channel broadcast receiving / transmitting device 8. In addition, a home terminal 14 and a cable modem 15 are newly installed in the modem terminating device 6 of the head end 5, the mixing and distributing device 7, and each door. In the case of delivering only conventional television broadcasting (the number of channels is 12), the common antenna 33 and the broadcast receiving / transmitting device 35 of the existing radio wave obstruction elimination facility are provided.
Can be used.

As a result, since it is not necessary to newly lay the coaxial cable 30 for the trunk line and the branch, the coaxial cable 30 and the supporting tool for supporting the coaxial cable 30 are the same as those in the conventional radio wave disturbance elimination facility (shown in FIG. 6). In the communication system using the existing radio wave obstacle elimination facility, the coaxial cable 30 and the bidirectional amplifier 10 form a bidirectional transmission path capable of bidirectional communication.

Next, the configuration of the bidirectional amplifier 10 in the existing radio wave disturbance elimination facility will be described with reference to FIG. As shown in FIG. 2, an input terminal 10a for inputting a signal from the bidirectional amplifier 10 installed in the mixing / distributing device 7 or the preceding stage, and a signal input to the input terminal 10a are separated into a downstream signal and an upstream signal. , A signal separating / combining circuit 10b for combining, a level adjuster 10f for adjusting the level of the down signal separated by the signal separating / combining circuit 10b, and a down signal amplifier 10c for amplifying the output of the level adjuster 10f.
A signal separating / combining circuit 10b that separates and combines the upstream signals from the downstream signal amplifier 10c and the output terminal 10g; a noise filter 10e that blocks noise included in the upstream signal separated by the signal separating / combining circuit 10b; Up signal amplifier 10 for amplifying the signal from the filter 10e
d, the level adjuster 10f that adjusts the level of the signal from the upstream signal amplifier 10d, and the signal from the signal separation / combination circuit 10b to the bidirectional amplifier 10 of the next stage, and the bidirectional amplifier 10 of the next stage. And an output terminal 10g for inputting the upstream signal from.

The level adjuster 10f is composed of an attenuator and an equalizer, and adjusts the signal level so that the input of the amplifier becomes a constant level. Further, the noise filter 10e is for reducing the ingress noise (the noise generated in each house is mixed with the transmission path and concentrated on the head end) included in the upstream signal.

The bidirectional amplifier 10 shown in FIG.
It has a frequency band of Hz. In addition, 770M
As for the frequency allocation of the Hz band, up to 222 MHz is used for transmission of conventional terrestrial television signals.
Other broadcasts, for example, independently produced programs, satellite broadcasts, and digital broadcasts are assigned to the frequency band exceeding 2 MHz. In addition, the Internet uses free channels other than the above assigned frequencies. The upstream signal of the Internet may use the band of 10 MHz to 50 MHz, or may use another free channel, and the time is selected. The bidirectional amplifier 10 replaces the conventional unidirectional amplifier 31 and has a frequency band of 222 MH.
It is extended to a wide band of 770 MHz from z.

Next, the attenuation of the transmission frequency and the signal level in the coaxial cable 30 will be described. In general, the amplifiers on the transmission line are arranged at every distance (basic span) where the signal is attenuated by 22 dB. Therefore, the 222 MHz unidirectional amplifier 31 (shown in FIG. 6) and the 770 MHz bidirectional amplifier 10 (shown in FIG. 1) compensate for the attenuation amount 22 dB of the coaxial cable 30. FIG. 3 shows 7
It is a figure which shows the amplification characteristic of the signal level with respect to the basic span S of the coaxial cable 30 in a 70 MHz bidirectional amplifier and a 222 MHz unidirectional amplifier. The frequency 77
The solid line shows the amplification characteristic of the signal level of 0 MHz, and the frequency 22
The dotted line shows the amplification characteristic of the signal level of 2 MHz. As shown in FIG. 3, in the coaxial cable 30, the attenuation amount of the signal level increases as the frequency of the transmission signal increases. The amount of attenuation of the coaxial cable 30 is proportional to the square root of the transmission frequency. The conventional unidirectional amplifier 31 (shown in FIG. 6) has an attenuation amount of 22 dB in the frequency band of 222 MHz, while the bidirectional amplifier 10 (shown in FIG. 1) has an attenuation amount of 42 dB in the frequency band of 770 MHz. . Therefore, the attenuation amount of the bidirectional amplifier 10 in the basic span S is
It is about twice the attenuation of the unidirectional amplifier 31.

In order to expand the frequency band from 222 MHz to 770 MHz by replacing the unidirectional amplifier 31 with the bidirectional amplifier 10 at the basic span of the unidirectional amplifier 31, as shown in FIG. Correction ability is required. Since it is technically and costly currently difficult to manufacture the bidirectional amplifier 10 having a correction capability of 42 dB, the distance to be placed on the coaxial cable 30 of the bidirectional amplifier 10 is set to 1 times the placement distance of the conventional unidirectional amplifier 31. / 2
By doing so, the characteristics of the transmission line with the same amount of attenuation as the conventional unidirectional amplifier 31 can be obtained.

FIG. 4 shows a 770 MHz bidirectional amplifier and two
It is a figure which shows the amplification characteristic of the signal level with respect to the installation distance of the coaxial cable in a 22 MHz unidirectional amplifier. The solid line shows the amplification characteristic of the signal level at the frequency of 770 MHz, and the dotted line shows the amplification characteristic of the signal level at the frequency of 222 MHz. As shown in FIG. 4, the replacement of the bidirectional amplifier 10 of the unidirectional amplifier 31 in the existing radio disturbance elimination facility is performed by ½ of the basic span S of the unidirectional amplifier 31 on the coaxial cable 30 (S shown in FIG. 4). Every 2). For example, when the unidirectional amplifier 31 of the conventional radio interference elimination facility is installed every 400 meters of cable length, the bidirectional amplification is installed every 200 meters of cable length. In addition, the protector 32 installed in each house
By replacing the two-way protector 12 with, it becomes possible to perform two-way communication in the existing radio wave disturbance elimination facility.

As described above, by using the radio interference elimination facility capable of bidirectional communication, the LAN (Local Area) can be operated by the cable modem 15 installed in each door.
By forming a network and providing a server at the head end 5, it is possible to send and receive e-mails within the area and provide area information.

Next, FIG. 5 shows the configuration of a network in which existing radio wave obstruction elimination facilities are connected by an optical cable 20 or the like. As shown in FIG. 5, a radio wave disturbance elimination facility 1 capable of two-way communication
The unidirectional amplifier 31 arranged between the coaxial cables installed in the existing radio interference elimination facility is replaced with the bidirectional amplifier 10, and the protector 32 arranged in each door is replaced with the bidirectional protector 12. .

As shown in FIG. 5, an optical cable 20 connects between the radio wave obstacle elimination facilities 1 capable of bidirectional communication. That is, the modem termination device 6 provided in the head end 5 of the radio wave disturbance elimination facility 1 capable of bidirectional communication and the modem termination device 6 of the radio disturbance elimination facility 1 capable of other bidirectional communication are connected by the optical cable 20. . Further, a wide area network can be formed by connecting a plurality of radio wave interference elimination facilities 1 capable of two-way communication with an optical cable 20.

Due to the nature of the radio wave obstruction elimination facility for coping with radio wave obstruction caused by terrain, almost all units in the target area are connected by coaxial cables. By making the transmission line of the existing radio interference elimination facility wideband and bidirectional, and connecting it to the optical fiber equipment provided at the town level, it becomes possible for each house to use the network.
This makes it possible to provide various services using the network. For example, it is possible to provide home-based medical services, local information, and administrative services for elderly people in rural depopulated areas.

Further, by connecting the existing radio interference elimination facility with an optical cable or the like, the broadcast receiving / transmitting apparatus conventionally installed for each radio interference elimination facility can be integrated into one place, so that the number of man-hours for maintenance and the like can be reduced. Can be reduced.

Although the communication system and network using the existing radio wave disturbance elimination facility of the present invention have been described in the embodiments in mountainous areas and sparsely populated areas, they can be used for radio wave obstacle elimination facilities such as high-rise buildings in urban areas. It is also possible to apply it.

[0034]

As described above, according to the communication system and the network using the existing radio interference elimination facility of the present invention, the amplifier on the coaxial cable of the existing radio interference elimination facility is converted to a wideband bidirectional amplifier. By replacing the protector of each house with a bidirectional type, it becomes possible to broaden the band of the transmission path and perform bidirectional communication.

Since the communication system using the existing radio wave disturbance elimination facility of the present invention can use the coaxial cable which has already been laid, it is possible to construct an inexpensive and wideband bidirectional communication system. In addition, it is possible to minimize the amount of waste due to facility renewal.

Furthermore, since a network with the outside can be formed by connecting the radio wave interference elimination facilities with each other by an optical cable, a service for multi-channel programs such as high-speed internet, satellite broadcasting, digital broadcasting similar to urban areas. Can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a communication system using an existing radio wave disturbance elimination facility according to the present invention.

FIG. 2 is a diagram showing a configuration of a bidirectional amplifier in an existing radio wave disturbance elimination facility according to the present invention.

FIG. 3 770 MHz bidirectional amplifier and 222 MHz
FIG. 5 is a diagram showing amplification characteristics of a signal level with respect to a basic span of a coaxial cable in the unidirectional amplifier of FIG.

FIG. 4 770 MHz bidirectional amplifier and 222 MHz
FIG. 6 is a diagram showing amplification characteristics of a signal level with respect to a laying distance of a coaxial cable in the unidirectional amplifier of FIG.

FIG. 5 is a diagram showing a configuration of a network in which existing radio wave disturbance elimination facilities capable of two-way communication are connected by optical cables or the like.

FIG. 6 is a diagram showing a configuration of a conventional radio wave obstruction elimination facility for coping with radio wave obstruction caused by terrain such as mountainous areas.

[Explanation of symbols]

1 Radio wave interference elimination facility capable of two-way communication 5 headend 6 Modem terminator 7 Mixing and distributing device 8 Multi-channel broadcasting receiver / transmitter 9 antenna 10 Bidirectional amplifier 10a input terminal 10b Signal separation / synthesis circuit 10c Downlink signal amplifier 10d upstream signal amplifier 10e noise filter 10f level adjuster 10g output terminal 12 two way protector 14 Home Terminal 15 cable modem 17 PC 20 optical cable 21 WAN 30 coaxial cable 31 Unidirectional amplifier 32 protector 33 common antenna 34 receiver 35 Broadcast receiving / transmitting device

Claims (4)

[Claims] 1. In an existing radio wave obstruction elimination facility for stably receiving broadcast radio waves, which comprises a laid coaxial cable, a unidirectional amplifier, and a protector, the unidirectional amplifier arranged between the laid coaxial cables is used. A communication system using an existing radio wave disturbance elimination facility, characterized in that it is replaced with a wideband bidirectional amplifier, and the protector arranged in each door is replaced with a bidirectional protector to enable bidirectional communication. . 2. The bidirectional amplifier is arranged at every constant distance of the laid coaxial cable, and the attenuation amount of the laid coaxial cable is made equal to the attenuation compensation amount of the unidirectional amplifier. A communication system using the existing radio wave disturbance elimination facility according to Item 1. 3. The communication system using an existing radio wave obstruction elimination facility according to claim 1, wherein the two-way communication is an Internet connection. 4. A unidirectional amplifier arranged between coaxial cables installed in an existing radio interference elimination facility is replaced with a bidirectional amplifier, and a protector arranged in each door is replaced with a bidirectional protector to be bidirectional. In the existing radio disturbance elimination facility that enables communication of the above, the existing radio disturbance elimination facility that enables the two-way communication is connected to each other with an optical cable to form a wide area network. A network using obstacle resolution facilities.