WO2005122424A1

WO2005122424A1 - Communication system

Info

Publication number: WO2005122424A1
Application number: PCT/JP2005/010809
Authority: WO
Inventors: Takashi Matsuo; Koji Kawamoto; Kenichi Hirotsu; Takefumi Shimoguchi; Yoshihisa Asao; Katsuhiro Yada
Original assignee: Sumitomo Electric Industries, Ltd.
Priority date: 2004-06-14
Filing date: 2005-06-13
Publication date: 2005-12-22
Also published as: JP2005354635A

Abstract

There is provided a communication system including a plenty of nodes almost without lowering the transfer rate. The communication system includes: a first communication system using an existing multi-branch cabled electric communication network (50) as a signal transmission path; a second communication system using the wiring (10) distributed to each of the homes (2A, 2B, …) as a signal transmission path; and signal relay means (20) for performing communication between the two systems. The first communication system has a first PLC modem (11) connected to an upper-node network (300) in a communication main line (52a). The second communication system has a second PLC modem (12) in the wiring (10). The signal relay means (20) performs communication to/from the first PLC modem (11) and to/from the second PLC modem (12). By using the signal relay means (20), it is possible to perform communication between the different signal transmission paths.

Description

Specification

Communications system

Technical field

The present invention relates to a communication system that performs communication using a power line. In particular, the present invention relates to a communication system in which the transmission speed of a communication signal does not easily decrease even when the number of nodes increases.

Background art

[0002] In recent years, communication using power lines, for example, power line communication (PLC) that superimposes a communication signal on a low-voltage distribution line to perform high-speed communication has been studied (for example, see Non-Patent Documents). 1).

FIG. 6 is an explanatory diagram schematically showing an outline of a PLC communication system, and shows a case where a PLC user house is a detached house. Hereinafter, the same reference numerals in the drawings denote the same components. This method is used for communication through a power line for supplying power to the PLC user house 200 as shown in FIG. In this example, the optical fiber cable 103 is used for communication from the upper network 300 to the transformer 102 disposed on the telephone pole 101, and the low-voltage distribution line 100 and the service line 201 are used for communication to the power house 200 on the transformer 102 side. Power lines such as indoor wiring 202 are used. On the telephone pole 101, there is a PLC modem 104 (parent modem) connected to the upper network 300 and the low-voltage distribution line 100, and in the house 200, a PLC modem communicating with the parent modem 104 is provided. It has 203 (child modem). In the example shown in FIG. 6 and the example shown in FIG. 7 described below, an example is shown in which the parent modem 104 is provided with a media converter (MC) for converting an optical signal / electrical signal. is there.

[0004] In the above configuration, for example, when a PLC user receives a PLC signal, the PLC signal transmitted from the host network 300 to the optical fiber cable 103 is transmitted to the parent modem connected to the connection box 105. Modulation / demodulation is performed at 104 and the low voltage side (secondary side) of the transformer 102 is injected. Then, it is modulated / demodulated by the child modem 203 through the low-voltage distribution line 100 → the service line 201 → the electric energy meter 204 → the distribution board 205 → the indoor wiring 202 → the outlet 206 of the transformer 102. It is received by being extracted by the terminal device 207 such as a computer IP phone. PLC user When the user sends a PLC signal, the signal goes through the reverse route to the above case.

FIG. 7 shows a case where the PLC user house is an apartment house. In this example, an optical fiber cable 103 is used for communication from a higher-level network 300 to a power equipment room 400 in which a power equipment 401 such as a transformer and a switch is housed. Use low-voltage distribution line 100 for communication up to 200 B and 200 C. The basic configuration is almost the same as that of the single-family house shown in Fig. 6 above. The parent modem 104 is composed of an optical fiber cable 103 and a low-voltage distribution line 100 from the power equipment 401 to each of the houses 200A, 200B, and 200C. The child modem 203 is connected to the indoor wiring 202 of each of the houses 200A, 200B, and 200C, and communicates with the parent modem 104.

[0006] In the above configuration, for example, when a PLC user transmits a PLC signal, a communication signal transmitted from the terminal device 207 is modulated / demodulated by the child modem 203, and the indoor wiring 202 → the power distribution It is injected into the low voltage side (secondary side) of the power equipment 401 via the panel 205 → the electric energy meter 204 → the distribution line 100. The signal is modulated / demodulated by the parent modem 104 from the low voltage side of the power device 401 and transmitted to the upper network 300 via the optical fiber cable 103. PLC user power When receiving a PLC signal, it goes through the reverse route to the above transmission.

As shown in FIGS. 6 and 7, in a PLC communication system, one parent modem 104 can communicate with a plurality of child modems 203. At this time, a plurality of child modems 203 may communicate with the parent modem 104 using the same power line. Therefore, the parent modem 104 uses a time division multiplexing method in which time is assigned to a plurality of signals (data) for transmission, or a frequency division multiplexing method in which a frequency band is assigned to a plurality of signals for transmission. The signal is assigned to 203.

[0008] On the other hand, communication networks such as telephones and cable televisions for transmitting audio signals and video signals via communication lines have been constructed. The user's house can receive signals by being connected to a station that distributes these signals by a communication line.

Non-Patent Document 1: Kiyoshi Eto, "Current Status of Power Line Communication (PLC)," Interface, CQ Publishing Company, September 2000, p.70-81

Disclosure of the invention

Problems the invention is trying to solve [0009] As described above, the parent modem can perform one-to-many communication with the child modem. However, if the transmission speed is to be maintained above a certain level, the number of child modems (number of nodes) that can communicate with one parent modem is limited. Therefore, it is desired to have a configuration for maintaining a transmission rate at or above a certain level while constructing a communication system having more nodes by increasing the number of nodes for one parent modem.

[0010] When the number of nodes for one parent modem increases, the time division multiplexing method is used.

However, the time allocated to each node is shortened, the delay is increased, and the transmission speed is reduced. In the case of frequency division multiplex transmission, the delay is small, so when the number of nodes is large, the possibility of using the frequency division multiplex method is high. However, even if the frequency division multiplexing method is used, if the number of nodes is too large, the time allocated to each node is shortened and the available frequency band is reduced, so that the transmission speed cannot be reduced.

[0011] Further, when a signal transmission path is constructed using only power lines, the power line between the parent modem and the child modem becomes longer, so that the signal attenuation increases, and communication between the parent modem and the child modem becomes impossible. Go to 《 Therefore, it is conceivable to install a signal relay device. However, even when the signal relay device is provided, if the number of nodes is too large, the transmission speed is reduced.

[0012] Therefore, a main object of the present invention is to provide a communication system that can have a larger number of nodes and can reduce a decrease in transmission speed.

Means for solving the problem

[0013] The present invention achieves the above object by using a communication line that constructs an existing communication network as a signal transmission path in addition to a power line.

That is, the communication system of the present invention includes a first communication system using an existing multi-branch wired telecommunication network as a signal transmission path, and a second communication system using a power line disposed in each house as a signal transmission path. Signal relay means for communicating between the first communication system and the second communication system.

[0015] If the number of nodes is increased for one parent modem, the transmission speed decreases, and high-speed communication becomes difficult. Also, if only the power line is used as the signal transmission path, it is conceivable to arrange a signal relay device when the distance between the parent modem and the child modem is long, but when the number of nodes connected to the signal relay device increases, it also increases. The transmission speed decreases. Therefore, the present inventors As a result of various investigations, it is possible to reduce the reduction in transmission speed and increase the number of nodes by constructing a signal transmission path with multiple transmission media and transferring signals between different transmission media. That we can do it. Specifically, for example, a PLC C modem a and a plurality of PLC modems aa that communicate with the PLC modem a are arranged on a certain transmission medium A, and the PLC modem aa is communicated on another transmission medium B. The modem aa functions as a parent modem, and a plurality of PLC modems bb that communicate with the PLC modem aa are arranged on the transmission medium B, and so on. By transmitting and receiving signals while functioning as a parent modem in another transmission medium B, the number of nodes provided in each transmission medium can be reduced. Therefore, for each transmission medium, a decrease in the transmission speed can be reduced, or the transmission speed does not decrease at all. Further, even if the number of nodes provided in each transmission medium is small, the total number of nodes can be provided in the entire system by adjusting the number of nodes arranged in all transmission media. The present invention is stipulated based on the above findings, and in particular, stipulates that a power line, an existing communication network, specifically, an existing multi-branch wire telecommunication network is used as a transmission medium. Hereinafter, the present invention will be described in more detail.

The communication system of the present invention includes two communication systems having different transmission media. The first communication system uses an existing multi-branch wired telecommunications network as a signal transmission path. The term “existing” in the present invention means, for example, that the cable is already laid and used for another purpose, or that the cable is already laid but is not currently used. A specific application is, for example, wired telecommunication, which is the original purpose of the construction of the multi-branched wired telecommunication network. The multi-branch wired telecommunications network is constructed from a communication trunk and a communication branch line branched from the communication trunk and distributed to each house. As such a multi-branch wired telecommunication network, for example, a wired radio communication network constructed in Russia or the like (for example, MGRS used in a mosque area) can be cited. The present invention uses a multi-branch wire telecommunications network composed of communication lines as a first signal transmission path, thereby reducing the amount of signal attenuation and using an existing one. Can be constructed at low cost. In the present invention, since an existing communication network is used, it is conceivable that this communication network is used for wired electric communication such as a wired radio. In such a case, the frequency band of the communication signal used in the present invention is the frequency band of the wired telecommunication signal. And make it different. Specifically, for example, the frequency is preferably 50 MHz or less, more specifically, 1.7 MHz to 50 MHz, particularly 1.7 to 30 MHz. When the communication network is not currently used, the frequency band of the communication signal used in the present invention is not particularly limited.

[0017] In the first communication system, it is preferable that the communication line (particularly, the communication trunk line) be provided with a power line carrier communication device and perform communication using the power line carrier communication device. A power line carrier communication device is a communication device that modulates a communication signal used in power line carrier communication.For example, a communication signal is transmitted to a signal transmission path such as a power line using a frequency band of 1.7 MHz to 30 MHz. A communication signal can be extracted from an injection / signal transmission path of a power line carrier communication apparatus, and one power line carrier communication apparatus can communicate with another plurality of power line carrier communication apparatuses. That is, the use of the power line carrier communication device enables one-to-many communication. As a modulation method, for example, a method of modulating at a carrier frequency of 50 MHz or less at any one of a single frequency, a plurality of frequencies, and a continuous frequency can be used. Specifically, a single frequency sine wave is distributed over a wide frequency range and transmitted, and when receiving, the original single frequency sine wave is restored to the original spread sine wave (SS) method. Orthogonal frequency domain multiplexing (OFDM) system, which divides the data into sine waves of frequency and densely superimposes the divided wave data, other FSK (Frequency Shift Keying) system, PSK (Phase Shift Keying; Phase modulation) method. In particular, OFDM is preferred.

[0018] A power line carrier communication device included in the first communication system (hereinafter, the device included in the first communication system is referred to as a first PLC modem) is connected to an upper network (hereinafter, referred to as an upper NT). It is possible to inject a communication signal of the upper NT power into a communication line (especially a communication trunk) serving as a signal transmission line of the first communication system, and to extract a communication signal that is injected by a signal relay unit described later and transmitted to the same communication line. And a configuration that can appropriately modulate and demodulate a communication signal. For example, a transmission / reception unit for transmitting and receiving communication signals, a power supply unit for obtaining power to operate each component such as the transmission / reception unit, an interface necessary for communication with the upper NT, and the like are provided. Can be mentioned. Also, a known PLC modem used as a so-called parent modem may be used as the first PLC modem. Note that the first PLC modem uses impedance matching to match the impedance of the communication line. Preferably.

[0019] Further, the first communication system may include a plurality of PLC modems for communicating with the first PLC modem, and perform communication by the PLC modem using a communication line. At this time, the first PLC modem functions as a so-called parent modem, and each of the plurality of PLC modems communicating with the first PLC modem functions as a child modem. As described above, the first communication system can perform one-to-many communication by using the communication line as the signal transmission path and using the PLC modem as the signal injection / extraction device.

[0020] In the second communication system, power lines provided in each house are used as signal transmission lines. In the second communication system, the user can easily communicate since the power lines laid in each house are used as the second signal transmission path. The user's house is equipped with terminal equipment that receives communication signals transmitted to the power line and transmits communication signals to the power line. The terminal device includes, for example, a computer. Then, the power line is provided with a power line carrier communication device (hereinafter, a device provided in the second communication system is referred to as a second PLC modem) for performing communication. The second PLC modem included in the second communication system can extract the communication signal that is injected by the signal joint stage described below and transmitted to the power line, and can inject the communication signal from the terminal equipment into the power line, and modulate and demodulate as appropriate. What you can do is listed. For example, there is a transmitter / receiver for transmitting and receiving communication signals, a power supply for providing power for operating the components such as the transmitter / receiver, a power supply for providing power to the components, an interface necessary for communication with terminal devices, and the like. No. Further, as the second PLC modem, a known PLC modem used as a so-called child modem may be used. One or more such second PLC modems may be provided in the user's house. The terminal device is connected to the second PLC modem so that the terminal device can communicate using the power line.

[0021] Further, in the second communication system, a plurality of PLC modems that communicate with the second PLC modem may be provided, and a network using power lines may be constructed in multiple stages. At this time, the second PLC modem functions as a so-called parent modem for a plurality of PLC modems provided in the lower-level network, and the plurality of PLC modems that communicate with the second PLC modem are: Each functions as a so-called child modem for the second PLC modem.

In the present invention, the first communication system and the second communication Signal relay means for relaying a communication signal with the system is provided. The signal relay means can extract a communication signal transmitted to the signal transmission line of the first communication system, inject the signal into the signal transmission line of the second communication system, and transmit the signal to the signal transmission line of the second communication system. There is a device having a configuration capable of extracting a communication signal to be transmitted and injecting it into a signal transmission path of the first communication system. For example, a first modem unit capable of communicating with a first PLC modem included in a first communication system, and capable of communicating with a plurality of second PLC modems included in a second communication system coupled to the first modem unit. One that includes a second modem unit. In this configuration, one signal relay unit can communicate with a plurality of nodes (second PLC modems). The first modem unit and the second modem unit may be an integral member or separate members, and the two modem units may be connected by a communication line such as an Ethernet (registered trademark) cable. By providing a plurality of such signal relay means for one first PLC modem and connecting each signal relay means to a plurality of second PLC modems, the transmission speed is reduced almost as a whole system It is possible to increase the number of nodes that do not do so.

As described above, in the communication system of the present invention including the first PLC modem, the signal relay means, and the second PLC modem, the communication system between the first PLC modem and the signal relay means, and the signal relay means and the second PLC modem respectively. Function as so-called parent and child modems. That is, in the first communication system, the first PLC modem is a parent modem and the signal relay means is a child modem. In the second communication system, the signal relay means is a parent modem and the second PLC modem is a child modem.

As described above, in the present invention, by providing two communication systems, it is possible to reduce the number of nodes arranged in each signal transmission path in each communication system, and to greatly increase the transmission speed. Suppress reduction. However, when the signal transmission path extends over a long distance, the signal is easily attenuated. In particular, in the second communication system using the power line as the signal transmission line, the signal is considered to be more easily attenuated than in the first communication system using the communication line as the signal transmission line. In such a case, it is preferable to arrange a signal relay device. Specifically, the first communication system relays signals between the first PLC modem and the signal relay means, and the second communication system relays signals between the signal relay means and the second PLC modem. No. The signal relay device included in the first communication system is a first communication modem unit that can extract the communication signal transmitted to the communication line and inject it into the communication line, and can communicate with the first PLC modem. ,signal There is a configuration including a second communication modem unit capable of communicating with the relay means (first modem unit). The signal relay device included in the second communication system can extract a communication signal transmitted to the power line and inject it into the power line, and can communicate with the signal relay means (second modem unit). A configuration including a power line modem unit and a second power line modem unit capable of communicating with the second PLC modem is exemplified. A known repeater may be used.

[0025] Further, in the case where the first communication system includes a plurality of different PLC modems A that communicate with the first PLC modem, or in the second communication system, the second PLC modem is caused to function as a parent modem. (Ii) When a plurality of other PLC modems B that communicate with the PLC modem are provided, a signal relay device may be provided between the first PLC modem and the PLC modem A and between the second PLC modem and the PLC modem B.

Here, the frequency band of the communication signal before being relayed by the signal relay device (the signal input to the signal relay device) and the frequency of the communication signal after the relay (the signal output by the signal relay device) If the band overlaps, the signal is transmitted on the same signal transmission path, and thus signal interference occurs. Therefore, it is preferable that the frequency bands used by both modem units in the signal relay device be different so as to prevent occurrence of signal interference. The frequency band that can be used by the system of the present invention is limited, for example, the usable frequency band is f Hz

1 or more f

Two

When the frequency is set to less than or equal to Hz, if this entire frequency band is allocated to the signal transmission lines before and after being relayed by the signal repeater, for example, f

One

~ F Hz

Half of 2 is allocated to the subsequent signal transmission line, and the other half is allocated. Since the frequency band to be allocated is reduced in this way, even if the signal relay apparatus performs frequency division multiplex transmission, the transmission speed may decrease as the number of nodes increases. If the signal repeater performs time division multiplexing transmission, the allocation time is shorter than in the case of frequency division multiplexing. Tends to decrease. Therefore, a filter that suppresses interference between the signal input to the signal repeater and the output signal should be placed near the signal repeater that should reduce such a reduction in transmission speed. Like,. By arranging such a filter, the communication signal is divided before and after being relayed by the signal relay device, so that the same frequency band can be used before and after the relay. That is, before and after being relayed by the signal relay device, The entire usable frequency band can be used, and a reduction in transmission speed is suppressed. Therefore, by providing the signal transmission device of the first communication system and the signal transmission device of the second communication system with the signal repeater and the filter, respectively, each communication system uses communication signals of the same frequency band. It can be performed.

[0027] The filter has such a characteristic that it attenuates a signal having the same frequency as a signal before being relayed by the signal relay device and does not interfere with a signal after being relayed by the signal relay device. . That is, the signal before being relayed by the signal relay device can be suppressed from being transmitted to the signal transmission line after the relay. However, wired telecommunication signals used in multi-branch wired telecommunication networks and low-frequency signals (for example, 50 Hz or 60 Hz signals) for power supply flowing through power lines are hardly attenuated or not attenuated at all. Shall be. Such a filter includes, for example, a filter composed of only a capacitor. It is often used at a high frequency. In order to effectively attenuate a communication signal, a ferrite core functioning as an inductance is used. It is preferable to use a combination of a magnetic member such as the above and a capacitor. In addition, it is preferable that such a filter has a good workability because it can be arranged without cutting a wiring constituting a signal transmission path such as a communication line or a power line that forms a multi-branch wired telecommunication network. For example, an attachment portion such as a clip that also has a conductive material strength may be provided. In addition, when the flight core is configured to be integrated with the divided pieces, it is easy to attach.

[0028] The filter is arranged near the signal relay device. For example, the upper signal injection / extraction point may be different from the lower signal injection / extraction point in the signal relay apparatus, and the signal injection / extraction point may be disposed between the two signal injection / extraction points. In addition, such a filter should be placed in the vicinity of the signal relay means for relaying the signal in the same manner as in the vicinity of the signal relay device.

[0029] A plurality of the first PLC modems may be provided for the entire multi-branch wired telecommunications network. Specifically, a plurality of first PLC modems may be respectively arranged for a plurality of communication trunks. By constructing a communication system with a signal relay unit and a second PLC modem for each first PLC modem, the number of nodes in the entire system can be increased. At this time, the communication signal used by one PLC If the communication signal used by the first PLC modem uses the same frequency band, signal interference may occur. Therefore, the frequency band used in each first PLC modem may be different, but as in the case of the above signal relay device, signal interference generated between the first PLC modems that reduces the reduction in transmission speed is suppressed. It is preferable to provide a filter between the first PLC modems. By providing such a filter between the first PLC modems, communication signals are divided before and after the filters, so that each first PLC modem performs communication using communication signals in the same frequency band. be able to. As the configuration of the filter, it is preferable to use a combination of a magnetic member such as a ferrite core and a capacitor, similarly to the configuration arranged near the signal repeater. In addition, it is preferable that the filter can be arranged without disconnecting the communication line that forms the multi-branch wired electric communication network. However, this filter is used in a multi-branch wired telecommunications network! It is assumed that the signal for wired telecommunication is hardly attenuated or not attenuated at all.

The invention's effect

[0030] The communication system of the present invention having the above-described configuration can increase the number of nodes while reducing a decrease in transmission speed of a communication signal by combining two communication systems having different transmission media. Excellent effects can be achieved. In particular, by using the existing communication network, it is possible to reduce the amount of signal attenuation and reduce the system construction cost.

In the system of the present invention, when the signal transmission path extends over a long distance, the signal relay device includes a filter near the signal relay device, so that both the signal relay device before and after the signal relay device relays the signal. Since the entire usable frequency band can be allocated in the signal transmission path, it is possible to reduce a decrease in signal transmission speed.

Brief Description of Drawings

[FIG. 1] (A) is a schematic configuration diagram of the communication system of the present invention, and (B) is a schematic configuration diagram of the communication system of the present invention including a plurality of first PLC modems in a multi-branch wire telecommunication network. (C) is a main configuration diagram having one modem unit.

FIG. 2 is a schematic diagram showing a form of the communication system of the present invention, wherein (A) is a form composed of a main communication group and a sub-communication group, and (B) is a service in which the sub-communication group is further lower. (C) shows a mode having a sub communication group on a communication branch line.

FIG. 3 is a schematic configuration diagram showing a configuration in which a filter is provided near a signal relay device in the system of the present invention.

FIG. 4 is an electric circuit diagram showing components of a filter used in the communication system of the present invention. (A) is a basic configuration including a capacitor and a ferrite core, and (B) is a ferrite core on both sides of the capacitor. (C) shows a configuration in which capacitors are placed on both sides of the ferrite core.

FIG. 5 (A) is a schematic configuration diagram illustrating an arrangement state of communication lines in an apartment house, and FIG. 5 (B) is a schematic configuration diagram near signal relay means.

FIG. 6 is an explanatory diagram schematically showing an outline of a PLC communication system, in which a PLC user house is a detached house.

FIG. 7 is an explanatory diagram schematically showing an outline of a PLC communication system, showing a case where a PLC user house is an apartment house.

Explanation of symbols

2A.2B House

10 Distribution line

11 First PLC modem

11F Huinoreta

12 Second PLC modem

13,14 PLC modem

20 Signal relay means

21 First modem section

22 Second modem section

30,31,32,33 PLC modem

40,60 signal repeater

41A, 41B, 42A, 42B, 44,45 Signal injection extraction point

43 Huinoleta 50 Multi-branch wired telecommunications network

51 Communication line

52a Telecommunication trunk

52b Communication branch line

53 Receiver

100 Low-voltage distribution line

101 telephone pole

102 Trance

103 fiber optic cape

104 Parent Modem

105 junction box

200,200A, 200B, 200C User house

201 Service drop

202 Indoor wiring

203 child modem

204 Watt hour meter

205 distribution board

206 outlet

207 Terminal equipment

220 Apartment

221 Support

300 Top Networks

400 Power Equipment Room

401 Power Equipment

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described.

Example 1

FIG. 1 (A) is a schematic configuration diagram of the communication system of the present invention, and FIG. 1 (B) shows a multi-branch wired telecommunication network. FIG. 1 is a schematic configuration diagram of a communication system of the present invention including a plurality of first PLC modems. The communication system of the present invention includes a first communication system using an existing multi-branch wired telecommunications network 50 as a signal transmission path, and a second communication system using a distribution line 10 disposed in each of the houses 2A, 2B,. A second communication system and signal relay means 20 for communicating between the first communication system and the second communication system.

In this example, the first communication system is a communication system using an existing wired radio communication network including a communication line 51 for transmitting a radio broadcast signal. The communication line 51 is connected to a communication trunk 52a connected to a station (not shown) for delivering a radio broadcast signal, and is connected to the communication trunk 52a and branched into a plurality of houses 2A, 2B,. It consists of a communication branch line 52b. A user of a wired radio can receive the same signal by providing a receiver (radio) 53 for a radio broadcast signal in each of the houses 2A, 2B. The first communication system includes a power line carrier communication device (first PLC modem 11) that is connected to the upper network 300 by the communication trunk 52a and communicates with the upper network 300. The transmission line is also used as a system that uses the first PLC modem 11 as a signal injection and extraction device.

[0037] The second communication system is a system that performs communication using a power line carrier communication device (hereinafter, simply referred to as a PLC modem) using the distribution line 10 as a signal transmission path, and is used in the second communication system. The user connects the (second) PLC modem 12 to the indoor wiring 202 of each house 2A, 2B... And connects a terminal device 207 such as a bath computer for transmitting and receiving communication signals to the PLC modem 12. Thus, communication can be performed via the terminal device 207.

[0038] The most characteristic feature of the present invention is that a signal relay means 20 is provided between two communication systems having different signal transmission paths, and a plurality of signal transmission paths are used. In particular, in the communication system shown in this example, a PLC modem is used for transmitting and receiving communication signals, so that one PLC modem can communicate with a plurality of different PLC modems. Specifically, a first PLC modem 11 disposed on the communication trunk 52a, a second PLC modem 12 provided in each of the houses 2A, 2B,..., And a signal for communication between the two modems 11, 12 Relay means 20.

[0039] The first PLC modem 11 is connected to the upper network 300, and can extract the communication signal of the upper network 300 to the communication trunk 52a, and also extracts the communication signal to the communication trunk 52a by the signal relay means 20. Communication signals that are input and transmitted can be extracted. The modulation method is 0 FDM. The basic configuration was the same as a known PLC modem used as a so-called parent modem. In this example, the impedance of the first PLC modem is matched to the impedance of the communication line 51 in order to inject and extract a communication signal to the communication line 51. In the example shown in FIG. 1 (A), one such first PLC modem 11 is arranged on a communication line 51 of one main communication group MG (described later), so that the entire multi-branch wired telecommunication network 50 has one. Are arranged.

[0040] The second PLC modem 12 can extract a communication signal injected by the signal relay means 20 and transmitted to a power line (the distribution line 10, the indoor distribution line 202, and the like), and can transmit a communication signal from the terminal device 207. The signal can be injected into the indoor wiring 202. The modulation method was OFDM. The basic configuration was the same as a known PLC modem used as a so-called child modem. In this example, such a second PLC modem 12 is provided in each house, and the second communication system as a whole has a plurality.

[0041] The signal relay means 20 includes a first modem unit 21 that communicates with the first PLC modem 11, and a second modem unit that is coupled to the first modem unit 21 and communicates with the plurality of second PLC modems 12. A modem section 22 may be provided, or as shown in FIG. 1C, only one modem section M for communicating with the first PLC modem 11 and a plurality of second PLC modems 12 may be provided. It may be something that can be obtained. In this example, a plurality of such signal relay means 20 are provided on the communication trunk 52a.

Then, in the example shown in FIG. 1A, the first PLC modem 11 is caused to function as a parent modem for a plurality of signal relay means 20, and each signal relay means 20 is caused to function as a child modem. That is, one main communication group MG is constituted by one first PLC modem 11 and a plurality of signal relay means 20 communicating with the first PLC modem 11. In the example shown in FIG. 1A, there is one main communication group MG. Further, each signal relay means 20 functions as a parent modem for each of the plurality of second PLC modems 12, and each second PLC modem 12 functions as a child modem. That is, one sub-communication group SG is constituted by one signal relay means 20 and a plurality of second PLC modems 12 communicating with the signal relay means 20. Therefore, although not shown in FIG. 1, one main communication group MG is provided with a plurality of sub communication groups SG.

[0043] In the communication system of the present invention having the above configuration, for example, a user is connected to a higher-level network. When a communication signal (PLC signal) is received from the network 300, it is transmitted from the host network 300 to the first PLC modem 11 via wiring such as an optical fiber cable, and is sent to the communication trunk line 52a → signal relay means 20 → distribution line. A communication signal can be extracted by the terminal device 207 via the route from 10 → indoor wiring 202 → second PLC modem 12. On the other hand, when the user transmits a communication signal (PLC signal), the terminal device 207 → second PLC modem 12 → indoor wiring 202 → distribution line 10 → signal relay means 20 → communication trunk line 52a → first A communication signal is transmitted to the host network 300 via the PLC modem 11.

In the communication system shown in FIG. 1 (A), in the main communication group MG, the first PLC modem 11 communicates only with each signal relay means 20 in the group MG, and each signal relay means 20 Communicates only with each second PLC modem 12 in the sub-communication group SG in which is located. Therefore, when looking at each of the groups MG and SG, the number of nodes is reduced, so that the transmission speed can be reduced while the number of nodes can be increased in the entire system. In particular, since the communication line 51 is used as a signal transmission path, the amount of signal attenuation can be reduced.

In this example, the frequency band used for communication signals is different from the frequency band used for wired radio.

Further, as in the communication system shown in FIG. 1 (B), the multi-branch wired telecommunication network 50 may have a plurality of first PLC modems in its entirety. That is, the first PLC modem 11 may be arranged in each of the plurality of communication trunks 52a, and a plurality of main communication groups MG may be provided. By providing a configuration in which each of the main communication groups MG includes a plurality of sub-communication groups, the number of nodes in the entire system can be further increased.

In the example shown in FIG. 1B, a filter 1 IF is arranged between the first PLC modems 11 to suppress signal interference between the first PLC modems 11. The filter 11F suppresses communication signals from interfering with each other between the first PLC modems, and separates communication signals before and after the filter 11F so that the same frequency band can be used before and after the filter 11F. In this example, the filter 11F used had a configuration in which the capacitor and the ferrite core were connected by wiring. By arranging such a filter 11F, it is possible to effectively reduce a decrease in transmission speed. Note that this filter 11F is used to control the radio flow that originally flows through the communication line that is the signal transmission path. The broadcast signal shall be passed.

FIG. 2 is a schematic diagram showing an embodiment of the communication system of the present invention. FIG. 2 (A) shows an embodiment composed of a main communication group and a sub communication group, and FIG. (C) shows a mode having a sub-communication group on a communication branch line.

The form shown in FIG. 2A is the same as the example shown in FIG. 1, and includes a plurality of signals that communicate between the first PLC modem 11 connected to the upper network 300 and the first PLC modem 11. It comprises a main communication group MG composed of the relay means 20, a signal relay means 20, and a plurality of second PLC modems 12 communicating with the signal relay means 20, and a sub communication group SG which is also powerful. The sub communication group SG is formed for each signal relay means 20, and a plurality of sub communication groups SG exist for one main communication group MG. In FIG. 2A, the communication branch line is omitted.

[0049] The form shown in FIG. 2 (B) is a form in which a certain sub communication group SG1 is set as an upper order and a further lower sub communication group SG2 is provided. Specifically, the sub communication group SG1 includes a second PLC modem 12 and another PLC modem 13 for communicating with the signal relay means 20, and the lower sub communication group SG2 includes the PLC modem 13 and the other. And a plurality of PLC modems 14 that communicate with the PLC modem 13. That is, the PLC modem 13 functions as a parent modem, and the PLC modem 14 functions as a child modem. As described above, in the system of the present invention, in the second communication system in which the power line is used as a signal transmission path, a plurality of PLC modems provided in the sub-communication group function as a parent modem and further communicate with the modem. With a lower sub-communication group with child modems! / In this way, the number of users can be increased by increasing the number of lower sub-communication groups.

[0050] Further, as shown in FIG. 2 (B), a PLC modem may be arranged on the communication line to form another communication group AG1 using the communication line as a signal transmission path. In the communication group AG1 shown in this example, the PLC modem 30 that communicates with the first PLC modem 11 is placed on the communication trunk line 52a, and the PLC modems 31 and 32 that communicate with the PLC modem 30 are placed on each communication branch line 52b. Let me. By using a PLC modem in this way, one PLC modem can communicate with multiple PLC modems, and the sub-communication group S Compared with G, the amount of signal attenuation can be reduced. Further, similarly to the example in which the power line is used as a signal transmission line, a lower communication group AG2 may be formed in the communication group AG1. In this example, the lower communication group AG2 includes a PLC modem 32 functioning as a parent modem and a plurality of PLC modems 33 communicating with the PLC modem 32.

FIG. 2C shows an example in which a communication group AG using a communication line as a signal transmission line and a sub communication group SG using a power line as a signal transmission line are provided. The communication group AG comprises a PLC modem 30 arranged on the communication trunk line 52a and communicating with the first PLC modem 11, a plurality of PLC modems 31 arranged on the communication branch line 52b and communicating with the PLC modem 30, and a PLC It comprises a modem 30 and signal relay means 20 for communication. As described above, the configuration may be such that the signal relay means 20 is disposed on the communication branch line 52b by using the communication branch line 52b that is connected only with the communication trunk line 52a. Example 2

[0052] When the signal transmission path becomes long, the amount of signal attenuation is likely to increase. Therefore, in such a case, it is preferable to arrange a signal repeater on the signal transmission path. For example, in the case of the embodiment shown in FIG. 2 (A), a signal relay device may be arranged on a communication trunk 52a for relaying a communication signal (PLC signal) between the first PLC modem 11 and the signal relay means 20. In order to relay communication signals between the signal relay means 20 and the second PLC modem 12, a signal relay device may be arranged on the distribution line 10. Similarly, in the case of the configuration shown in FIG. 2B, a signal relay device may be arranged on the communication trunk line 52a or the distribution line 10, or in the communication groups AG1 and AG2 using the communication branch line 52b, A signal relay device may be arranged on the communication branch line 52b for relaying communication signals between the modem 30 and the PLC modem 31, and between the PLC modem 32 and the PLC modem 33. Figure 2 (C) is the same. Further, the PLC modems 13 and 32 may be signal relay devices.

When the signal relay device is disposed between the first PLC modem 11 and the signal relay means 20, for example, the first communication modem unit that communicates with the first PLC modem 11 and the first communication modem unit One that includes a second communication modem unit that is coupled to perform communication with the signal relay unit 20. Between the signal relay means 20 and the second PLC modem 12, a first power line modem section for communicating with the signal relay means 20 and a second power line modem coupled to the first power line modem section for communicating with the second PLC modem 12. One that includes a power line modem unit may be used. Similarly, when arranging between PLC modem 30 and PLC modem 31, and between PLC modem 32 and PLC modem 33, One that includes two modem units for performing communication. A known repeater may be used. It is preferable that the frequency used by the first modem unit and the frequency used by the second modem unit be different so as to prevent signal interference.

Example 3

When a signal relay device is provided on the signal transmission line as in the second embodiment, and the signal relay device uses the time division multiplexing method, the transmission speed decreases as the number of nodes increases. Also, when the frequency division multiplexing method is used, by using different frequencies for the two modem sections, the frequency band usable in each modem section is narrowed, which may cause a reduction in signal transmission speed. . Therefore, in this example, a configuration will be described in which a filter is provided so that the transmission speed is hardly reduced even when the signal relay device is arranged. FIG. 3 is a schematic configuration diagram showing a configuration in which a filter is provided near a signal relay device in the system of the present invention. In this example, a form in which the signal relay device 40 is arranged on the distribution line 10 is shown. The feature of this example is that a filter 43 is provided near the signal relay device 40.

[0055] The filter 43 suppresses interference between communication signals before and after being relayed by the signal relay device 40, and also sets a frequency band used between a communication signal before relaying and a communication signal after relaying before and after the same. The two communication signals to be increased are divided so that the same frequency band can be used before and after. Note that the filter 43 is supposed to pass a radio broadcast signal or a low-frequency signal for power supply that originally flows through a communication line or a power line that is a signal transmission path.

In this example, points 41A and 41B at which the signal repeater 40 extracts the upstream communication signal transmitted to the distribution line 10, and points 42A at which the signal repeater 40 injects the extracted communication signal into the distribution line 10 , 42B are arranged with a filter 43. Then, when a communication signal in the same frequency band f as the communication signal input to the signal relay device 40 is transmitted rightward in FIG. 3 from the points 41A and 41B, it is attenuated by the filter 43 and almost to the right of the filter 43. It will not be transmitted. Then, it is assumed that the communication signal output from the signal repeater 40 has the same frequency band f as the above input, and even if the signal is transmitted from the injection points 42A and 42B to the left in FIG. It is attenuated and hardly transmitted to the left of the filter 43. In addition, the downstream communication signal (frequency band f) transmitted to the distribution line 10 is transmitted from points 42A and 42B.

y Similarly, when the signal is extracted by the signal repeater 40, if a communication signal of the same frequency band f as the communication signal input to the signal repeater 40 is transmitted leftward from points 42A and 42B in FIG. And is hardly transmitted to the left of the filter 43. Then, the communication signal output from the signal repeater 40 is assumed to be y having the same frequency band f as the above input, and even if the signal is transmitted rightward in FIG. 3 from the injection points 41A and 41B of the signal, the filter It is attenuated by 43 and hardly transmitted to the right of the filter 43. In addition, when uplink communication signals / downlink communication signals are controlled by the time division multiplexing method, f = f is set.

By providing a filter having the above characteristics, the usable frequency band before and after the input / output of the signal repeater can be made the same, and the transmission speed caused by the narrow signal frequency band can be reduced. Reduction can be effectively prevented.

FIG. 4 is an electric circuit diagram showing components of the filter. In the present example, the filter 43 includes a capacitor and a ferrite core, and a filter having a configuration in which the capacitor and the ferrite core are connected by wiring can be used. For example, there is a configuration A in which a capacitor C is arranged between two distribution lines 10 each having a ferrite core L arranged as shown in FIG. 4 (A). Also, as shown in Fig. 4 (B), configuration B has cores L on both sides of capacitor C, and configuration C has capacitors C on both sides of the core as shown in Fig. 4 (C). Thus, the filter function can be further improved. Further, it is more effective to adopt a configuration in which the configuration B is provided in multiple stages or a configuration in which the configuration C is provided in multiple stages. In this example, configuration A was used. Further, in this example, the capacitor is provided with a clip capable of gripping the distribution line 10, and the fly core is formed into an arc-shaped cross section by combining a pair of divided pieces having a semi-arc cross section.

The configuration was used. With this configuration, it is possible to dispose a filter that cuts off the power line that is the signal transmission path. Note that the distribution line 10 is usually configured with two or three wires. This is the same for the above embodiment. In this example, two cases are shown.

[0059] Further, in this example, the example in which the signal relay device is arranged on the power line has been described. However, the signal relay device may be arranged on a communication line such as a communication trunk line or a communication branch line. At this time, the filter is preferably arranged near the signal repeater. Example 4

[0060] In the above-described third embodiment, an example is shown in which a filter is provided in the vicinity of a signal relay device disposed on a power line. In this example, a filter is provided in the vicinity of a signal relay device disposed on a communication line. Here is an example. FIG. 5A is a schematic configuration diagram illustrating an arrangement state of communication lines in an apartment house, and FIG. 5B is a schematic configuration diagram near a signal relay unit. The communication line 51 is supported by a support portion 221 arranged on the roof of the apartment house 220 as shown in FIG. 5 (A), and is branched into a plurality of communication branch lines (not shown) arranged in each house. . Each house can receive a radio broadcast signal through the communication line 51 and the communication branch line. Further, in the present example, the signal relay device 60 is disposed on the support portion 221. The signal repeater 60 extracts the communication signal transmitted to the right of the communication line 51 at the signal injection extraction point 44 in FIG. 5 (B), transmits the relay signal to the signal injection extraction point 45, and The communication signal transmitted to the left of the line 51 is extracted to the signal injection extraction point 45, and the relay signal is transmitted to the signal injection extraction point 44. In the present example, the filter 43 is arranged near the signal relay device 60. Specifically, the filter 43 is arranged between the signal injection and extraction points 44 and 45 as in the third embodiment. By arranging the filters in this way, it is possible to reduce a decrease in the transmission speed as in the third embodiment.

Industrial applicability

[0061] The communication system of the present invention is suitable for use when performing power line carrier communication. In particular, by using the system of the present invention, it is possible to easily increase the number of nodes with a small decrease in signal transmission speed.

Claims

The scope of the claims

[1] a first communication system using an existing multi-branch wired telecommunications network as a signal transmission path,

A second communication system in which a power line arranged in each house is used as a signal transmission path,

A communication system comprising: signal relay means for communicating between the first communication system and the second communication system.

2. The communication system according to claim 1, wherein the first communication system and the second communication system include a power line carrier communication device, and perform communication using the power line carrier communication device.

3. The communication according to claim 1, wherein the first communication system performs communication using a signal in a frequency band different from a frequency band of a wired telecommunication signal used in the multi-branch wired telecommunication network. system.

[4] The communication system according to claim 1, wherein the multi-branch wire telecommunication network is a wire radio communication network.

5. The communication system according to claim 1, wherein at least one of the first communication system and the second communication system includes a signal relay device that relays a signal transmitted on a signal transmission path. .

[6] A claim, comprising a filter arranged near the signal relay device to suppress interference between a signal input to the signal relay device and a signal output from the signal relay device. 6. The communication system according to 5.

[7] The communication system according to claim 6, wherein the filter has a configuration that can be arranged without cutting a wiring configuring a signal transmission path.

[8] The communication system according to claim 6, wherein the filter comprises a magnetic member and a capacitor.

[9] In the first communication system and the second communication system, in a communication system including a signal relay device and a filter in a signal transmission path, communication is performed using communication signals in the same frequency band. 7. The communication system according to 6.

[10] The signal transmission path of the first communication system includes a plurality of power line carrier communication devices connected to an upper network, and suppresses interference between the power line carrier communication devices between the power line carrier communication devices. The communication system according to claim 1, further comprising a filter. M

11. The communication system according to claim 10, wherein the plurality of power line carrier communication devices perform communication using communication signals in the same frequency band.