JP2008124628A - Power-line carrier communication apparatus and power-line communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power-line carrier communication apparatus or a power-line carrier communication system, which is capable of preventing a so-called disguise and improving the reliability of a network. <P>SOLUTION: When a newly added slave modem 2A has no communications with a master modem 1 for a certain time, certification information corresponding to the slave modem 2A on a certification information management table stored in the storage 23 of the master modem 1 is erased. On the other hand, certification information on a certification information management table stored in the storage 23 of the slave modem 2A is erased. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power line communication device and a power line communication system used for power line communication using a power line as a transmission line.

  A power line communication system (hereinafter referred to as a PLC system) is a high-frequency signal (as a communication signal ranging from several kHz to several tens of MHz or more) on a power line through which a commercial current with a frequency of 50 Hz or 60 Hz flows. .) Is superimposed to perform communication. Such a PLC system has attracted attention as a system capable of transmitting and receiving large-capacity data using an existing power line (also called a distribution line or a light line) drawn into each house without using a dedicated communication line. ing.

In order to construct a network such as a LAN using the PLC system, it is necessary that power line communication devices (a PLC modem, a slave modem, an information home appliance, etc.) constituting the network have authentication information of the network. is there. The authentication information includes a network ID (SSID: Service Set Identifier) for specifying the network, an encryption key for encrypting a signal transmitted and received in the network, a house code, and the like.
Since the power line communication device included in the network has such authentication information, it is possible to perform communication by distinguishing data of another network and data of the own network.

  Therefore, when adding a new power line communication device to an existing network, it is necessary to set common authentication information in the network for a power line communication device newly operating in the network. And when setting authentication information with respect to a new power line communication apparatus, it is necessary to specify a new power line communication apparatus after distinguishing from other power line communication apparatuses.

When the network is configured with the power line communication device, the setting of the SSID, the encryption key, and the house code is generally required manually by the user, so that the setting work is complicated and troublesome.
Therefore, in a home network system that performs communication using a power line, the insertion of a power plug is detected, and a house code assigned in advance for each home is connected to each terminal device capable of power line communication with a power plug connected to the outlet. A home network system for automatic setting has been proposed (see Patent Document 1).
JP 2003-78456 A

  However, in the home network system disclosed in Patent Document 1, if a communication outlet that automatically sets authentication information is provided simply by connecting a power plug, the terminal device is connected to the outlet without permission from the network administrator. After that, there is a concern about so-called impersonation in which information in the network is stolen by connecting the authenticated terminal device to a nearby power line.

  In view of such a situation, in the power line communication apparatus or power line communication system of the present invention, the power line communication apparatus capable of erasing the stored authentication information under certain conditions with respect to the terminal apparatus for which the provision of authentication information has been completed once Another object is to provide a power line communication system.

  The power line communication device according to the first invention is a power line communication device in which the power line is used as a transmission line, and an outlet capable of power line communication and a power plug of a terminal device capable of power line communication are connected to the outlet. Then, a control unit that generates authentication information of the terminal device, a storage unit that stores the authentication information generated by the control unit, and a timing processing unit, the timing processing unit counts the time for holding the authentication information. The storage unit is characterized in that the storage is erased according to the timing.

  According to the power line communication device of the first invention, the authentication information is automatically generated and stored based on the connection of the outlet and the power plug to the outlet, but the communication with the terminal device is performed for a certain period. If not, the authentication information in the power line communication device is stored and erased. Even if the authentication information is acquired by impersonation, if the period until the terminal device is connected to the power line again exceeds the predetermined period, communication with the power line communication device can no longer be performed.

  The power line communication system according to the second invention is a power line communication system for transmitting and receiving authentication information between a power line communication device in which the power line is used as a transmission line and a terminal device connected to the power line communication device. The power line communication device includes an outlet capable of power line communication, a control unit, and a transmission unit, and the terminal device includes a power plug capable of power line communication, a reception unit, a storage unit, and a time measurement processing unit. When the power plug of the terminal device is connected to the outlet, the control unit generates time information for storing the authentication information of the terminal device and the storage of the authentication information, and the transmission unit transmits the authentication information and time information through the outlet. Is transmitted to the receiving unit of the terminal device, and the receiving unit receives the authentication information and the time information from the transmitting unit of the power line communication device through the power plug. The timekeeping processing unit measures the time for holding the authentication information according to the time information received by the receiving unit, and the storage unit stores the authentication information received by the receiving unit, and the memory is erased according to the timekeeping. Features.

  According to the power line communication system according to the second aspect of the present invention, the authentication information in the terminal device is stored and erased when communication with the power line device is not performed for a certain period in the terminal device to which the authentication information is given. Then, if the period until the power line communication device that has obtained the authentication information by impersonation connects the terminal device to the power line again has passed the predetermined period, it can no longer communicate with the terminal device.

  According to the present invention, in a power line communication device or a power line communication system, when communication with a terminal device for which the provision of authentication information has been completed is not performed for a certain period, the storage of authentication information related to the terminal device can be deleted. Therefore, the reliability of the network can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the element which attached | subjected the same or corresponding code | symbol in different drawing shall show the same or corresponding element.

[Home network]
FIG. 1 shows an example of a home network (LAN) constructed using the power line communication device (parent modem) of the present invention. In this network, power line communication devices 1, 2 and 3 are connected to in-house power lines 9a, 9b and 9c in the houses A, B and C, and independent networks (LANs) are provided in the houses A, B and C, respectively. ) Has been built. In the following, the networks constructed in the houses A, B, and C are referred to as a network A, a network B, and a network C, respectively.

The in-home power lines 9a, 9b, 9c are extended from the transformer 5 installed on the utility pole or the like to the houses A, B, C. The transformer 5 converts a medium voltage into a low voltage (for example, 200 V), and a medium voltage distribution line for distributing a three-phase AC medium voltage (for example, 6 kV) on the primary side thereof. 8 is connected, and a power line 9 is connected to the secondary side.
The power line 9 connected to the secondary side of the transformer 5 is a common power line common to a plurality of houses A, B, and C, and the home power lines 9a and 9b of the houses A, B, and C are connected to the common power line 9. , 9c are branched.

Each home power line 9a, 9b, 9c is appropriately provided with a home outlet 10, and the power line communication devices 1, 2, 3 are connected to any one of these outlets 10 so that the networks A, B, C are connected to each other. Has been built. Each power line communication device 1, 2, 3 transmits a PLC signal and receives power supply through power lines 9a, 9b, 9c.
Each of the power line communication devices 1, 2, and 3 constituting each network A, B, and C includes at least one parent modem 1, and this parent modem 1 corresponds to the power line communication device of the present invention.

  The parent modem 1 communicates with a terminal device composed of the child modem 2 in the networks A, B, and C, the information home appliance 3 capable of power line communication, and the like by using a PLC signal. The modem 1 serves as an access point (AP) for the child modem 2 and the information home appliance 3 to perform power line communication. For this reason, the child modem 2 and the information home appliance 3 are the end points (EP) of the network system.

  The parent modem 1 of this embodiment has a built-in broadband router function and can access an external network such as the Internet. When the parent modem 1 has a broadband router function, a termination device 6 such as an optical fiber 7 or ADSL is connected to the parent modem 1 via a signal line S1, and the parent modem 1 is connected to an external network via the termination device 6. Communication is possible.

[Configuration of parent modem and child modem]
FIG. 2 shows a basic configuration for power line communication between the parent modem 1 and the child modem 2.
Both the parent modem 1 and the child modem 2 have the same basic configuration, and a coupling circuit 20 that superimposes a PLC signal on the power line 9 and transmission / reception of the PLC signal transmitted to the power line 9 inside the housing 19. PLC transmitting / receiving unit 21 that performs modulation / demodulation processing, etc., a control unit 22 that generates authentication information, a storage unit 23 that stores authentication information, and an LED that notifies the user of the setting processing state of authentication information And a display unit 24.

In addition to the basic configuration described above, the parent modem 1 includes a communication outlet 25 that also functions as a service outlet, and a detection unit 26 that detects the connection of the power plug 28 to the outlet 25.
Each of the parent modem 1 and the child modem 2 includes a power plug 28 at the tip of a power cord 27 extending from the housing 19, and this power plug 28 is connected to the home outlet 10 of the houses A, B, and C. By connecting, it is connected to the PLC signal transmission line and the power lines 9a, 9b and 9c which are power supply lines. Each of the modems 1 and 2 includes an Ethernet (registered trademark) cable connection port 29, and a PC (personal computer) 30 connected to the port 29 and communication based on the Ethernet (registered trademark). It can be performed.

The control unit 22 of each modem 1 and 2 distinguishes the networks A, B, and C of each house and has an SSID as a network ID for recognizing the own network A, B, or C. This network ID is transmitted by being included in the transmission data of the PLC signal, and it can be distinguished whether the received PLC signal is transmitted from the own network or transmitted from another network. Note that a house code can be used as the authentication information of the networks A, B, and C.
Further, the control unit 22 of each of the modems 1 and 2 has encryption key data for encrypting the PLC signal. This encryption key is set differently for each of the networks A, B, and C so that the PLC signal cannot be read from devices outside the networks A, B, and C.

The authentication information such as the network ID, the encryption key, and the house code may be freely set by the user, but here, the parent modem 1 is configured to be automatically generated. This saves typing.
The automatically generated authentication information is generated based on the MAC address assigned to the parent modem 1. More specifically, authentication information is generated by adding a random number to the MAC address, and by creating authentication information in this way, it can be made unique and difficult to guess.

  When the detection unit 26 detects that the power plug 28 is connected to the communication outlet 25, the control unit 22 of the parent modem 1 stores authentication information and authentication information based on this detection. Time information is generated and stored in the storage unit 23 of the parent modem 1 and transmitted to the child modem 2. The child modem 2 stores the authentication information received from the parent modem 1 and the time information for storing and holding the authentication information in the storage unit 23 of the child modem 2.

[Configuration of timekeeping processing section]
The timekeeping processing unit 40 of the parent modem 1 measures the holding period of the authentication information stored in the storage unit 23 of the parent modem 1. The timing processing unit 40 of the child modem 2 also measures the holding period of the authentication information stored in the storage unit 23 of the child modem 2 in the same manner as the timing processing unit 40 of the parent modem 1.
The timekeeping processing unit 40 of the parent modem 1 includes a counter 401, a binarization circuit unit 402, and a 50/60 Hz switching circuit unit 403 as shown in FIG. The binarization circuit unit 402 converts the commercial frequency on the home power line 9a into a pulse signal. The 50/60 Hz switching circuit unit 403 is a changeover switch for selecting either 50 Hz or 60 Hz according to the area where the parent modem 1 is used. The counter 401 increments or decrements the numerical value in the counter based on the pulse signal obtained from the binarization circuit unit 402 and the switching information of the 50/60 Hz switching circuit unit 403. The counter 401 is a loop type counter, and in the case of 32 bits, when it reaches FFFFFFFFH (hexadecimal number) and is incremented, it becomes 00000000H.

  In an area with a commercial frequency of 50 Hz, the counter 401 is activated every 20 milliseconds and the numerical value is incremented. After 1 hour, it is incremented 180 thousand times, and after 1 day, it is incremented 4,320 thousand times.

  As described above, it is assumed that the timekeeping processing unit 40 uses the commercial frequency of the home power line 9a as a preferable mode for performing accurate timekeeping. However, in some cases, the slave modem 2 may use the home power line 9a. May be removed from the outlet 10. For this reason, the timekeeping processing unit 40 of the child modem 2 may use other means without using the commercial frequency on the home power line 9a. For example, if a capacitor having a large electric capacity is used to supply power to the storage unit 23 and the authentication information stored in the storage unit 23 is held only for the time determined by the time constant of the capacitor, The configuration is simpler and preferable.

(Configuration of detection unit)
3 and 4 show examples of the configuration of the detection unit 26 provided in the parent modem 1, wherein (a) is a front view of the outlet 25 for power supply and communication, and (b) is a side view of the outlet 25, respectively. It is.
3 includes a pin-type detection switch 31 protruding from the central portion of the outlet 25, and the switch 31 is provided so as to be freely retractable along the insertion direction of the outlet 25. For this reason, when the power plug 28 is inserted into the outlet 25, the detection switch 31 is pushed into the inside of the housing 19, thereby detecting the connection of the power plug 28.

On the other hand, the detection unit 26 shown in FIG. 4 is configured by the communication outlet 25 itself provided in the housing 19 so as to be freely retractable. For this reason, when the power plug 28 is inserted into the outlet 25, the outlet 25 is pushed into the inside of the housing 19, and the connection of the power plug 28 is detected by turning the contact ON / OFF.
Note that the method for detecting the connection of the power plug 28 is not limited to these, and a minute thermal change, current change, and impedance change generated at the power terminal when the power plug 28 is connected to the outlet 25 can be detected by a heat detection sensor or current. A method of detecting with a detection sensor or an impedance detector can also be employed.

[How to set authentication information]
In the home network shown in FIG. 1, it is assumed that a parent network 1, a first child modem 2, and an information home appliance 3 are already connected to a certain network A, and the second child modem is connected to this network A. Assume that 2A (“terminal device”) is newly added. In this case, the newly added modem 2A needs to be set by the parent modem 1 with authentication information such as a network ID of the network A, an encryption key used in the network A, and a house code.

  FIG. 2 shows a modem connection for setting authentication information of the child modem 2A in the case of adding the child modem 2A as described above. In this embodiment, the parent modem 1 that is the notification source of the authentication information is shown. This is done by connecting the power plug 28 of the child modem 2A, which is the notification destination of authentication information, to the communication outlet 25.

When the power plug 28 is connected as described above, the detection unit 26 of the parent modem 1 detects the connection, and based on this detection, the control unit 22 of the parent modem 1 detects the network ID, encryption key, and house code. Etc. and time information for storing and holding the authentication information are automatically generated. The authentication information and the time information are stored in the storage unit 23 of the parent modem 1 and are transmitted from the outlet 25 to the child modem 2A through the power cord 27 for a predetermined time.
On the other hand, when the control unit 22 of the slave modem 2A receives the authentication information in the PLC transmission / reception unit 21, the control unit 22 stores the authentication information and time information in the storage unit 23.

When the storage unit 23 of the parent modem 1 and the child modem 2A stores the authentication information and time information, the control unit 22 of each of the modems 1 and 2A blinks the display unit 24 such as an LED, thereby setting the authentication information to the user. Is notified of the completion.
Thereafter, the power plug 28 of the child modem 2A is removed from the outlet 25 of the parent modem 1, and the child modem 2A is inserted into any home outlet 10 in the network A, so that the child modem 2A becomes a new one in the network A. It will be added as a communication device.

  2 illustrates the case where the power plug 28 of the child modem 2A is connected to the outlet 25 of the parent modem 1, and the authentication information is set in the child modem 23. However, the information home appliance capable of power line communication is illustrated. 3 (“terminal device”) is connected to the outlet 25 of the parent modem 1, authentication information can be automatically set for the information home appliance 3.

[Authentication information management table]
FIG. 5 shows a management table of authentication information such as the network ID, encryption key, and house code stored in the storage unit 23 of the parent modem 1 as described above. In the management table, “the number of managed child modems (n) is two, that is, the child modem 2 and the child modem 2A in the case of the parent modem 1 in FIG. Data up to the “counter value at the scheduled time” is stored for two units, that is, repeated twice.

  The “child modem MAC address” is a MAC address assigned to each child modem. A child modem to be managed is identified and managed by this MAC address. The authentication network information “network ID”, “encryption key”, and “house code” store the data generated by the parent modem 1 as described above.

  The “counter value at the end of communication” stores the value of the counter 401 when the communication with the child modem is completed. For example, if the value of the counter 401 when the parent modem 1 finally ends communication with the child modem 2A (when the communication session with the child modem is disconnected) is 0 (decimal number), “the counter value at the end of communication” "0" is stored.

  “Counter value when authentication information is scheduled to be erased” is set with a counter value when authentication information is scheduled to be erased. For example, if the authentication information is deleted one hour after the last communication between the parent modem 1 and the child modem 2A, data corresponding to 180 thousand (decimal number) is set. If the authentication information is deleted after one day, data corresponding to 4,320 thousand (decimal number) is set.

  As described above, the contents of the authentication information management table stored in the storage unit 23 of the parent modem 1 have been described with reference to FIG. 5, but basically the same authentication information is stored in the storage unit 23 of the child modem 2A. A management table is stored. In this case, since the authentication information management table manages the child modem 2A itself, the “number of child modems managed” is set to 1, and the “counter value when authentication information is scheduled to be erased” from the “child modem MAC address”. It is sufficient to store the data up to one.

[How to delete authentication information]
The child modem 2A is newly added to the network A of FIG. 1, and the parent modem 1 generates authentication information of the child modem 2A. As described above, this authentication information is stored in the authentication information management table of the storage unit 23 in the parent modem 1. The parent modem 1 transmits this authentication information to the child modem 2A, and the child modem 2A stores the authentication information in the authentication information management table of the storage unit 23 of the child modem 2A.

  If the newly added child modem 2A does not communicate with the parent modem 1 for a certain period of time, authentication information corresponding to the child modem 2A on the authentication information management table stored in the storage unit 23 in the parent modem 1 is displayed. to erase. On the other hand, the authentication information on the authentication information management table stored in the storage unit 23 in the child modem 2A is deleted. Note that the case where the parent modem 1 and the child modem 2A do not communicate with each other is the case where the parent modem 1 and the child modem 2A are connected to the power line 9a via the outlet 10 but are not connected in the communication protocol. The case where the power plug 28 of the child modem 2A is removed from the outlet 10 is also included.

  A case where the parent modem 1 deletes the authentication information of the child modem 2A on the authentication information management table stored in the storage unit 23 of the parent modem 1 will be described with reference to FIGS. When the parent modem 1 finally communicates with the child modem 2A as described above, the value of the counter 401 in FIG. 6 is stored in the “counter value at the end of communication” on the authentication information management table in FIG. . At this time, if the authentication information is to be deleted after one hour, add 180 thousand (the counter value for one hour: decimal number) to the “counter value at the end of communication” to the “counter value when the authentication information is scheduled to be deleted” Store the numeric value.

  Then, the control unit 22 in FIG. 6 monitors whether or not the numerical value of the counter 401 matches the “counter value at the end of communication” on the authentication information management table in FIG. All the authentication information corresponding to the child modem 2A on the authentication information management table is deleted. After the erasure, even if the child modem 2A tries to communicate with the parent modem 1, the child modem 2A cannot communicate with the parent modem 1 because there is no authentication information regarding the child modem 2A in the parent modem 1.

  Although the case where the authentication information related to the child modem 2A is deleted in the parent modem 1 has been described, the same deletion operation in the child modem 2A itself is performed in the authentication information management table stored in the storage unit 23 of the child modem 2A. Erase information.

As a result of deleting the authentication information, even if there is an outsider who connected the child modem 2A to the outlet 25 of the parent modem 1 without permission from the network administrator and illegally obtained the authentication information generated by the parent modem 1, If the certain period is set to a certain short period, communication with the child modem 2A cannot be performed after the certain period until the child modem 2A is reconnected to the power line 9, and information leakage due to impersonation is prevented in advance. be able to.
In the above description, the authentication information on the authentication information management table of both the parent modem 1 and the child modem 2A is deleted. In order to prevent impersonation and improve the reliability of the network, the authentication information on the authentication information management table of either the parent modem 1 or the child modem 2A may be deleted.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the above meaning, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is an overall configuration diagram of a home network using power line communication. FIG. It is a figure which shows the connection method of a parent modem and the newly added child modem. It is an enlarged view of the outlet socket for showing the example of composition of a detecting part. It is an enlarged view of the electrical outlet for showing the other structural example of a detection part. It is a figure which shows the table which manages the authentication information stored in the memory | storage part of a parent modem and a child modem. It is a block diagram which shows a time measuring process part.

Explanation of symbols

S1 Signal line 1 Parent modem (AP: Power line communication device)
2 Child modem (EP: Terminal device)
3 Information appliances (EP: Terminal device)
DESCRIPTION OF SYMBOLS 5 Transformer 6 Termination apparatus 7 Optical fiber 8 Medium voltage distribution line 9 Power line 9a In-home power line 9b In-home power line 9c In-home power line 10 In-home outlet 19 Housing 20 Coupling circuit 21 PLC transmission / reception part 22 Control part 23 Storage part 24 Display part 25 Electric power supply Outlet 26 for concurrent communication Detection unit 27 Power cord 28 Power plug 29 Connection port 30 Personal computer 31 Detection switch 40 Timekeeping processing unit 401 Counter 402 Binarization circuit 403 50/60 Hz switching circuit A Home network B Home network C Home network

Claims (2)

A power line communication device in which a power line is used as a transmission line,
An outlet capable of power line communication,
A control unit that generates authentication information of the terminal device when a power plug of the terminal device capable of power line communication is connected to the outlet;
A storage unit for storing the authentication information generated by the control unit;
A timekeeping processing unit,
The time processing unit times the time for holding the authentication information,
The power line communication device, wherein the storage section is erased according to the timing. A power line communication system for transmitting and receiving authentication information between a power line communication device used as a transmission line and a terminal device connected to the power line communication device,
The power line communication device includes an outlet capable of power line communication, a control unit, and a transmission unit,
The terminal device includes a power plug capable of power line communication, a receiving unit, a storage unit, and a time measuring unit.
In the power line communication device,
When the power plug of the terminal device is connected to the outlet, the control unit generates authentication information of the terminal device and time information for storing the authentication information,
The transmitting unit transmits the authentication information and the time information to the receiving unit of the terminal device through the outlet,
In the terminal device,
The reception unit receives the authentication information and the time information from the transmission unit of the power line communication device through the power plug,
The timing processing unit counts the time for holding the authentication information according to the time information received by the receiving unit,
The power line communication system, wherein the storage unit stores the authentication information received by the receiving unit, and the storage is erased according to the timekeeping.

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