JP4526850B2 - CATV system in the building - Google Patents

Description

  The present invention relates to an in-building CATV system suitable for enjoying a high-speed Internet service.

  Conventionally, in order to distribute a reception signal from a receiving antenna that receives broadcast radio waves or a broadcast signal supplied from an external CATV system to a plurality of rooms in a building, transmission using a coaxial cable in the building There is known an in-building CATV system configured to wire a line and transmit a transmission signal such as a reception signal or a broadcast signal to a terminal terminal of each room via the transmission line.

  Also, in this type of in-building CATV system, if the transmission line in the building is connected to an external CATV system that provides Internet services, an information terminal such as a personal computer can be used from each room in the building. As a result, the Internet can be easily accessed.

  For this reason, in general, in an apartment complex in an area that can be connected to an external CATV system that provides Internet services, by connecting the transmission line wired for the in-building CATV system to the external CATV system, Residents can individually subscribe to an external CATV system and enjoy Internet services.

In addition, in order to allow residents to connect to the Internet using the transmission line of the in-building CATV system in an apartment house, etc., a trunk line modem for connecting to a higher-level provider on the head end side of the in-building CATV system, There is also known a system in which facilities for connecting to the Internet such as a center modem for transmitting and receiving data to and from a resident side cable modem and a router for connecting these modems are installed (for example, Patent Document 1) reference).
JP 2001-358742 A

  However, in any of the above prior arts, since the center modem on the center side of the system and the cable modem on the subscriber side are used for connection to the Internet, the communication speed at the time of Internet connection is 30 Mbps. It was limited to such a degree that a higher communication speed could not be realized.

  In other words, the center modem and cable modem used for data communication in the CATV system need to modulate communication data (uplink data and downlink data) for the Internet into a frequency band different from other transmission signals such as a television broadcast signal. For this reason, it is designed in conformity with Docsis (Data Over Cable Service Interface Specifications), which is a communication method developed for that purpose.

  However, in the Internet service by Docsis, the realizable communication speed is about 30 Mbps. Therefore, in the in-building CATV system, it is possible to connect to an external CATV system that provides the Internet service as in the past, or to connect to the Internet. The communication speed at the time of connecting to the Internet (or other network) cannot be further increased only by installing the equipment for use.

  The present invention has been made in view of these problems. In an in-building CATV system built in a building, it can be accessed at high speed by an external network such as the Internet via a transmission line (coaxial cable) of the system. The purpose is to do.

  In the in-building CATV system according to claim 1, which has been made to achieve such an object, an access point for a wireless network is provided in a repeater for connecting a subscriber-side network to an external network different from the CATV system. The antenna terminal of this access point is connected to the transmission line of the in-building CATV system.

  Therefore, on the terminal side of the system, if an antenna for wireless network access is connected to the terminal terminal, an information terminal compatible with the wireless network can be connected to the access point via this antenna and the transmission line. As a result, it becomes possible to access an external network such as the Internet via this access point.

  As a wireless network access point, a so-called wireless LAN access point having a communication speed of 54 Mbps has been put into practical use and will be further increased in the future. Accordingly, it is possible to realize an in-building CATV system that can access an external network such as the Internet at a higher speed.

  By the way, in general, the in-building CATV system is configured such that signals are transmitted from the top floor to the lower floor in an apartment house or the like because the receiving point is on the rooftop of a building, etc. A directional coupler is used so that unnecessary signals do not flow from the downstream side of the transmission line.
  For this reason, if an external network connection repeater or access point is installed on the lower floor (such as the first floor) of an apartment house, and the access point is connected to the middle (or end) of the transmission line, it can be accessed in most rooms. Points can no longer be used.

  Therefore, in order to make an access point available from each room in a general in-building CATV system, a head end unit that sends a reception signal from a reception antenna or a broadcast signal from an external CATV system to a transmission line is required. It is necessary to install a repeater or access point for external network connection on the top floor of the building to be installed, and connect the access point to the transmission line.

  However, for this purpose, the connection line to the external network must be wired in the building, and the effect of the reduced wiring obtained by using the transmission line of the in-building CATV system is reduced. When connecting a connection line to an existing building, there is also a problem that the aesthetics of the building is impaired.

  In view of this, in the in-building CATV system according to claim 1, further, via a transmission line, a head end unit for sending at least one of a reception signal from the reception antenna and a broadcast signal from an external CATV system to the transmission line. A re-transmission means is provided for re-transmitting the wireless network communication signal transmitted from the terminal side to the terminal side.

  As a result, according to the in-building CATV system according to claim 1, the communication signal transmitted from the terminal side of the in-building CATV system can be retransmitted to the terminal side by the retransmission means. It is possible to access an external network such as the Internet from any place where the terminal terminal is installed, regardless of where the access point is connected to the transmission line in the building.

  Also, in this case, the wiring length in the building of the connection line to the external network can be minimized, so that the labor of construction can be saved and the aesthetics of the building can be saved by the wiring. It is also possible to prevent damage.

  The re-transmission means may be configured to return the communication signal transmitted from the terminal side to the terminal side, but more preferably, the communication signal is amplified as described in claim 2. It may be configured to retransmit to the terminal side.

  In this way, when the scale of the in-building CATV system is large, that is, when the distance of the transmission line from the head end portion to the terminal terminal at the terminal becomes long, the distance between the terminal terminal at the terminal and the access point is increased. Thus, it is possible to prevent a communication signal transmitted and received from being attenuated excessively, leading to communication failure or speed reduction.

  Note that wireless LAN access points that use 2.4 GHz band radio waves (specifically, those that comply with IEEE802.11b / EEE802.11g, which is a wireless LAN standard compatible protocol) are known. This frequency band is the same frequency band as the output from the CS antenna that receives a television broadcast radio wave from a communication satellite (CS), down-converts the received signal, and outputs it.

  Therefore, by using an in-building CATV system constructed to transmit a received signal from this type of CS antenna, an access point using a 2.4 GHz band radio wave is used. The CATV system of the present invention can be realized by using the existing building equipment as it is.

  On the other hand, as described above, the communication speed of an access point for a wireless network is currently about 54 Mbps. However, a plurality of access points can be used simultaneously if they have different radio communication frequencies. it can. If a plurality of access points are operated simultaneously, the communication speed in the in-building CATV system can be set to a speed obtained by multiplying the communication speed of each access point by the number of access points.

  Therefore, in order to further increase the communication speed of data communication using the transmission line of the in-building CATV system, the wireless communication frequency is set to a different frequency in the transmission line as described in claim 3. The antenna terminals of a plurality of access points may be connected to a transmission line, and each of the plurality of access points may be connected to a repeater for connecting to an external network via a router having an address conversion function.

  Specifically, in the case of a wireless LAN access point compliant with the above-mentioned communication standard “IEEE802.11b / IEEE802.11g”, if the wireless communication frequency is set to a frequency that does not overlap with each other, at least four devices can be used simultaneously. If four such access points are connected to the transmission line of the in-building CATV system and each access point is connected to a repeater for connecting to an external network via a router having an address conversion function, the in-building CATV The communication speed of data communication that can be realized using the transmission line of the system can be 216 Mbps (= 54 Mbps × 4).

  In this case, however, the external network connected to the transmission line via the access point must also be capable of high-speed communication. For this purpose, as described in claim 4, the external network Is preferably an optical communication network for Internet connection.

  That is, in the case of an optical communication network for connecting to the Internet, high-speed communication of 1000 Mbps or higher is possible. Therefore, if an optical communication network capable of such high-speed communication is connected as an external network, an in-building CATV system is used. Higher speed data communication can be realized.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an explanatory diagram showing a schematic configuration of the entire in-building CATV system of the present embodiment.
As shown in FIG. 1, in the in-building CATV system of this embodiment, one end is connected to the BS / CS antenna 8 and the other end is transmitted to the external bidirectional CATV system via the protector 6 and the tap-off 4. A mixer 9 connected to the line is provided.

  The mixer 9 receives a received signal from the BS / CS antenna 8 (frequency: 1032 MHz to 2602 MHz, hereinafter referred to as “BS / CS-IF”) and a downstream signal (frequency: 70 MHz to 770 MHz) from an external bidirectional CATV system. , Hereinafter referred to as “CATV going down”) and sent to the transmission line 12 wired in the building, and the upstream signal transmitted from the terminal side of the in-building CATV system via this transmission line 12 (Frequency: 10 MHz to 55 MHz, hereinafter referred to as “CATV uplink”) is transmitted to an external bidirectional CATV system.

  Next, a bidirectional amplifier 10 is provided on the transmission line 12 drawn from the mixer 9. This bidirectional amplifier 10 amplifies the “BS / CS-IF” and “CATV downlink” signals input via the mixer 9, outputs them to the terminal side, and outputs “CATV uplinks” input from the terminal side. In this embodiment, since a wireless LAN signal (frequency: 2400 MHz to 2500 MHz) is transmitted from the terminal side, the wireless LAN signal is transmitted to the mixer 9 side. Is also provided with a function of amplifying and returning to the terminal side (function as a retransmission means of the present invention). This point will be described in detail later.

  Further, a distributor 11 is provided on the downstream side of the bidirectional amplifier 10, and the distributor 11 distributes the transmission line 12 into a plurality (four distributions in the figure), and each of the distributed transmission lines. On 12, a plurality of series units (directional couplers) 13 which are arranged in each room in the building and serve as terminal terminals of the in-building CATV system are provided.

  As a result, in a room where the series unit 13 is arranged, a set-top box (STB) 15 or a BS / CS tuner 16 is connected to the series unit 13 via a duplexer 14 or the like, so that a desired television is obtained. The broadcast can be viewed on the television receiver 17.

  On the other hand, an Internet connection device 20 is provided at the end of the transmission line 12 so as to be able to connect to the Internet via the transmission line 12 from the room in which the series unit 13 is arranged.

  The Internet connection device 20 includes an optical cable 21 drawn from a network (here, an optical communication network) on the side of a provider (such as a telephone company) that provides a connection service to the Internet, a transmission line 12 in a building, Are connected so as to be capable of data communication. Inside, a media converter 22 for mutually converting an optical signal transmitted / received via the optical cable 21 into an electrical signal, and four accesses for wireless LAN are provided. A point 26 and a router 24 for connecting each access point 26 and the media converter 22 are provided. In each access point 26, an antenna terminal to which an antenna for wireless communication is originally connected is connected to the transmission line 12 via a four distributor 27.

  Here, in the present embodiment, the access point 26 is used for a wireless LAN conforming to the above-mentioned communication standard “IEEE802.11b / EEE802.11g” and having a wireless communication speed of 54 Mbps. Further, a router 24 having an address conversion function is used so that data can be relayed bidirectionally between the four access points 26 and the media converter 22. Such wireless LAN access points, routers with an address conversion function, and the like are well known in the art and will not be described in detail.

  In the in-building CATV system of the present embodiment configured as described above, for example, if a wireless LAN antenna 28 is directly connected to the transmission line 12, a wireless LAN interface card is connected via this antenna and the transmission line 12. An information terminal 18 such as a personal computer equipped with an access point 26 can be connected to the access point 26, so that the information terminal 18 can access the Internet via the access point 26, the router 24, the media converter 22, and the like. Become.

  However, since the transmission line 12 is embedded in a wall or the like, the wireless LAN antenna 28 cannot be connected directly. Even if it can, if the antenna 28 is directly connected to the transmission line 12, Since the signal transmission is adversely affected, when the information terminal 18 is actually connected to the Internet, the antenna 28 is connected to the series unit 13 of each room as shown in FIG.

  Further, since the serial unit 13 is configured by a directional coupler so that unnecessary signals do not flow from the downstream side of the transmission line 12, the serial unit 13 transmits the Internet connection device 20 as in the present embodiment. When connected to the end of the line 12, the information terminal 18 cannot be connected to the access point 26 even if the antenna 28 is connected to the series unit 13.

  Therefore, in the present embodiment, the bidirectional amplifier 10 serving as the head end device of the in-building CATV system is provided with the function as the retransmission means of the present invention, and the wireless signal transmitted from the terminal side via the transmission line 12 is used. The LAN signal is retransmitted to the terminal side.

Hereinafter, the configuration and operation of the bidirectional amplifier 10 for this purpose will be described with reference to FIG.
As shown in FIG. 2, the bidirectional amplifier 10 includes a first terminal T1 to which the mixer 9 is connected via the transmission line 12, and a second terminal T2 to which the distributor 11 is connected via the transmission line 12. These terminals T1 and T2 are respectively provided with low-pass filters (hereinafter referred to as LPFs) 31, whose cutoff frequencies are set to 770 MHz, for example, to pass the “CATV downlink” and “CATV uplink” signals, respectively. 35 and high-pass filters (hereinafter referred to as HPFs) 41 and 48 whose cutoff frequency is set to 1000 MHz, for example, are connected to pass the “BS / CS-IF” signal.

  Then, the “CATV down” signal input from the first terminal T1 via the LPF 31 is input to the amplifier 33 via the HPF 32 (cut-off frequency: 70 MHz, for example) and amplified to a predetermined level by the amplifier 33. , HPF 34 (cutoff frequency: 70 MHz, for example), LPF 35, and second terminal T 2, the signal is transmitted onto transmission line 12 on the terminal side.

  The “CATV upstream” signal input from the second terminal T2 via the LPF 35 is input to the amplifier 37 via the LPF 36 (cut-off frequency: 55 MHz, for example), and is amplified to a predetermined level by the amplifier 37. , LPF 38 (cut-off frequency: 55 MHz, for example), LPF 31, and first terminal T 1.

  In addition, the “BS / CS-IF” signal input from the first terminal T1 via the HPF 41 includes an LPF 42 (cut-off frequency: 2400 MHz, for example) and an HPF 43 (cut-off frequency: 2500 MHz, for example) connected in parallel. Then, the signal is input to the mixer 44 and further input from the mixer 44 to the amplifier 45 to be amplified to a predetermined level.

  The LPF 42 and the HPF 43 are for blocking a frequency component corresponding to the wireless LAN signal from the “BS / CS-IF” signal, and form a so-called band-eliminate filter (BEF). Therefore, these two filters may be configured with one BEF.

  On the other hand, wireless LAN signals transmitted from the terminal side, that is, the Internet connection device 20 and the antenna 28 (specifically, the interface card 19 provided in the information terminal 18) are transmitted from the second terminal T2 via the HPF 48 to both sides. Input to the direction amplifier 10. The input wireless LAN signal is input to the amplifier 50 via the hybrid circuit 47 and a band pass filter 49 (hereinafter referred to as BPF) whose cutoff frequency is set to 2400 MHz to 2500 MHz, for example. Amplified to a predetermined level by the amplifier 50.

  The wireless LAN signal amplified by the amplifier 50 and the “BS / CS-IF” signal amplified by the amplifier 45 are mixed by the mixer 46, and the hybrid circuit 47, HPF 48, and second terminal T2 are mixed. Through the transmission line 12 on the terminal side.

  That is, the bidirectional amplifier 10 of the present embodiment not only amplifies each signal of “BS / CS-IF”, “CATV downlink”, and “CATV uplink” bidirectionally, but also wirelessly input from the terminal side. The LAN signal is amplified and retransmitted to the terminal side.

  Therefore, according to the in-building CATV system of the present embodiment, the wireless LAN signal transmitted from the terminal side can be retransmitted to the terminal side by the bidirectional amplifier 10, and anywhere in the building Even if the antenna 28 is connected to the serial unit, the information terminal 18 can be connected to the access point 26 via the antenna 28 and the transmission line 12.

  As described above, according to the in-building CATV system of the present embodiment, the access point 26 for wireless LAN is connected to the transmission line 12 so as to be able to access the external Internet. In addition, since an apparatus capable of high-speed communication that cannot be realized by a conventional CATV system is used, an in-building CATV system capable of performing data communication at a higher speed than conventional can be constructed.

  In addition, since each part of the Internet connection device 20 such as the access point 26 of the wireless LAN can be obtained easily and relatively inexpensively, when actually constructing the in-building CATV system of this embodiment, It can be easily and inexpensively constructed.

  Furthermore, if the bidirectional amplifier 10 according to the present embodiment is provided in the head end portion of the in-building CATV system, the Internet connection device 20 can be connected anywhere on the transmission line 12 downstream. Therefore, the in-building CATV system of this embodiment can be realized very easily by improving the existing system.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, A various aspect can be taken within the technical scope of this invention.
For example, in the above-described embodiment, the bidirectional amplifier 10 has been described as having the function as the retransmission unit of the present invention. However, the retransmission unit may be configured as a single device or a mixer. 9 or distributor 11 or other transmission equipment.

  Further, when the Internet connection device 20 can be arranged on the head end side, it is not necessary to provide a device having a function as a retransmission means, and the Internet CATV system of the present invention can be realized by the Internet connection device 20 alone.

  Furthermore, in the above embodiment, the wireless network access point for the wireless LAN conforming to “IEEE802.11b / EEE802.11g” is used as the access point for the wireless network. You may use things.

  Also, the wireless LAN signal that flows through the transmission line 12 is not necessarily in the frequency band (2400 MHz to 2500 MHz) of the above embodiment, and is a frequency band that can be transmitted through the transmission line 12 and does not overlap with other broadcast signals. Any belt is acceptable.

It is explanatory drawing showing the structure of the whole building CATV system of embodiment. It is a block diagram showing the structure of the bidirectional | two-way amplifier of embodiment.

Explanation of symbols

  4 ... tap-off, 6 ... protector, 8 ... BS / CS antenna, 9 ... mixer, 10 ... bidirectional amplifier, 11 ... distributor, 12 ... transmission line, 13 ... series unit, 16 ... BS / CS tuner, 17 DESCRIPTION OF SYMBOLS ... Television receiver, 18 ... Information terminal, 19 ... Interface card, 20 ... Internet connection device, 21 ... Optical cable, 22 ... Media converter, 24 ... Router, 26 ... Access point, 28 ... Antenna, 27 ... 4 distributor, 33 ... Amplifier 37 ... Amplifier 44 ... Mixer 45 ... Amplifier 46 ... Mixer 47 ... Hybrid circuit 50 ... Amplifier.

Claims (4)

At least one of a reception signal from a receiving antenna that receives broadcast radio waves and a broadcast signal distributed from an external CATV system is transmitted through a transmission line wired in the building. In the building CATV system that transmits to the terminal terminal,
An access point for a wireless network is connected to a repeater for connecting a subscriber-side network to an external network different from the CATV system;
Connect the antenna terminal of the access point to the transmission line ,
In addition, for the wireless network transmitted from the terminal side via the transmission line to the head end unit that sends out at least one of the reception signal from the reception antenna and the broadcast signal from the external CATV system to the transmission line. An in-building CATV system provided with a re-transmission means for re-transmitting a communication signal to the terminal side .   The in-building CATV system according to claim 1, wherein the retransmission unit amplifies the communication signal and retransmits the communication signal to the terminal side.   The transmission line is connected to antenna terminals of a plurality of access points set to different frequencies for radio communication frequencies,
  The in-building CATV system according to claim 1 or 2, wherein the plurality of access points are connected to the repeater via a router having an address translation function.   The in-building CATV system according to any one of claims 1 to 3, wherein the external network is an optical communication network for Internet connection.

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