JP4742785B2 - Power line communication management method - Google Patents

Description

The present invention, in the power line communication (PLC) network, about the power line communication management method to respond quickly to deterioration in transmission characteristics due to connection of a new noise source.

  In a power line communication network, when a new electric device is connected, noise is generated on the power line, and transmission characteristics change. If this is left unattended, there will be an effect such as packet loss in power line communication.

As a noise removal method in a multicarrier power line communication method, a method of reducing power line signal output and estimating noise is known (Patent Document 1).
Japanese Patent No. 3385266

  In a power line communication network, it is difficult to suppress noise generated by connection of a new electric device. As countermeasures against the deterioration of transmission characteristics due to new noise, there are only methods that rely on retransmission of lost signals or provide more error correction capability.

The present invention aims to present rapidly manageable power line communication management method to the deterioration of the transmission characteristics due to the new noise source connections.

A power line communication management method according to the present invention is a power line communication management method in which a general management apparatus manages power line communication conditions by a PLC modem in a power line communication network, and a PLC modem newly connected to the power line communication network A step of transmitting an identification signal for identifying an electric device that communicates using a modem to the general management device, supplying power to the electric device after a predetermined time has elapsed, and when the general management device receives the identification signal, the electric device A profile indicating power line communication conditions corresponding to fluctuations in transmission characteristics on the power line communication network due to connection and noise caused by the electrical equipment, and a step of searching for the presence or absence of storing a profile related to the identification information; The management device stores the profile related to the identification signal. If have, together with the profile of the power line communication conditions to be used in the power line communication network to change in response to the change and the noise of the transmission characteristic, and stores the modified profile in association with the identification signal, A step of notifying the PLC modem configuring the power line communication network of information indicating the changed profile, and the overall management device indicates the stored profile when the profile related to the identification signal is stored The information processing apparatus includes a step of notifying information to a PLC modem configuring the power line communication network, and a PLC modem notified of information indicating the profile applies the notified profile to itself.

  According to the present invention, when a known electric device participates in a power line communication network, it can be changed in advance to a profile that allows for the deterioration of transmission characteristics due to new noise or the like, so that packet loss can be prevented in advance. Thereby, communication can be maintained stably.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic block diagram of an embodiment of the present invention.

  Outlets 12, 14, and 16 are connected to the power line 10 in the home or office.

  The overall management apparatus 20 is connected to the PLC modem 26 via the power line 22 and the signal line 24. The PLC modem 26 is also connected to the outlet 12 with a power plug 28. When the power plug 28 is connected to the outlet 12, the overall management device 20 and the PLC modem 26 are powered. The overall management apparatus 20 communicates with the other PLC modems 36 and 46 connected to the power line 10 and communicates with the electrical devices 30 and 40 by power line communication using the PLC modem 26. Although details will be described later, the overall management apparatus 20 uses the PLC modem 26 to instruct the PLC modems 36, 46 to indicate the profiles indicating the carriers used by the PLC modems 26, 36, 46 for communication and the bit rates of the carriers. To do.

  The electric device 30 is connected to the PLC modem 36 via the power line 32 and the signal line 34. The PLC modem 36 is also connected to the outlet 14 with a power plug 38. When the power plug 38 is connected to the outlet 14, the PLC modem 36 is first powered, and the electrical device 30 is powered after a certain time.

  The electric device 40 is connected to the PLC modem 46 through the power line 42 and the signal line 44. The PLC modem 46 is also connected to the outlet 16 with a power plug 48. When the power plug 48 is connected to the outlet 16, the PLC modem 46 is powered first, and the electric device 40 is powered after a certain time.

The PLC modems 36 and 46 have the same configuration. The configuration of the PLC modem 36 will be described as an example. On the power line between the power plug 38 and the electric device 30, a power line connection / cutoff circuit 50 that can select connection and disconnection of the power line is arranged. The control circuit 52 controls the power line connection / cutoff circuit 50. Power line connection / cutoff circuit 50 is in a cutoff state in unpowered state, in accordance with an instruction from the control circuit 52, the connection state. When the power line connection / cutoff circuit 50 is in a cut-off state, the electric device 30 is not supplied with power even if the power plug 38 is connected to the outlet 14. When the power plug 38 is connected to the outlet 14 and the power line connection / cutoff circuit 50 is in the connected state, the electric device 30 is supplied with power.

  The memory 54 stores an identification signal that identifies the PLC modem 36. In actual use, the PLC modem 36 is built in the electric device 30. Therefore, the identification signal stored in the memory 54 is also a signal for specifying the electrical device 30.

  The transmission / reception circuit 56 is connected to a power line between the power plug 38 and the power line connection / cutoff circuit 50, and can communicate with other PLC modems 26 and 46 by power line communication. The control circuit 52 sets the carrier according to the profile information from the overall management device 20 and the number of bits allocated to each carrier in the transmission / reception device 56 for data communication. The transmission / reception circuit 56 is connected to the electrical device 30 via the signal line 34. The electrical device 30 can communicate with the overall management apparatus 20 and other electrical devices 30 using the transmission / reception circuit 56.

  A characteristic operation of the present embodiment will be described. It is assumed that the power plug 38 is connected to the outlet 14. First, the PLC modem 36 is powered. The control circuit 52 initializes the inside, sets an initial profile that can be used universally in the transmission / reception circuit 56, reads the identification signal stored in the memory 54, and transmits the identification signal to the overall management device 20 by the transmission / reception circuit 56. Send. The initial profile is a profile that can always communicate with other PLC modems, and is used to inform others of its own activation and to transmit basic information. Thereafter, the control circuit 52 waits for reception of profile information to be set from the overall management apparatus 20.

  The control circuit 52 also places the power line connection / cutoff circuit 50 in a connected state after a predetermined time has elapsed since the identification signal was transmitted. Thereby, the electric equipment 30 is fed. When the electric device 30 is fed, noise enters the power line 10 and changes the impedance of the power line 10. As a result of these, the transmission characteristics of power line communication deteriorate. The overall management apparatus 20 changes the profile used for power line communication in response to fluctuations in transmission characteristics on the power line 10, specifically, fluctuations in the signal-to-noise ratio, and sets the changed profile in the PLC modem 26. At the same time, the PLC modems 36 and 46 are notified. The control circuit 52 of the PLC modems 36 and 46 sets the notified profile in each transmission / reception circuit 56.

  FIG. 2A shows a profile in an ideal transmission state. The horizontal axis represents frequency, and the vertical axis represents the number of bits allocated to each channel or carrier. FIG. 2B shows an example of the noise of the newly connected electrical device and the attenuation characteristic caused thereby. The horizontal axis represents the frequency, and the vertical axis represents the attenuation amount (dB) of the attenuation characteristic and the noise power. FIG. 2C shows the profile after the change. The horizontal axis represents frequency, and the vertical axis represents the number of allocated bits per channel or carrier. The overall management apparatus 20 stores the changed profile shown in FIG. 2C in association with the identification signal of the newly joined electric device. That is, the overall management apparatus 20 can specify a noise source by an identification signal, and stores profile information that is effective after the electric device 30 is added to the power line network in association with the electric device 30.

  Here, it is assumed that the power plug 38 is removed from the outlet 14. Then, noise on the power line 10 is reduced, and transmission characteristics of power line communication are improved. The overall management apparatus 20 changes the profile used for power line communication according to the improvement of the transmission characteristics on the power line 10, sets the changed profile in the PLC modem 26, and notifies the active PLC modem 46. The control circuit 52 of the PLC modem 46 sets the notified profile in the transmission / reception circuit 56.

  Assume that the power plug 38 is connected to the outlet 14 again. Then, as described above, the control circuit 52 of the PLC modem 36 transmits an identification signal to the overall management apparatus 20, and after a certain period of time, sets the power line connection / cutoff circuit 50 in the connected state. Based on the identification signal notified from the PLC modem 36, the overall management apparatus 20 reads the profile adopted at the previous connection from the storage device, sets the profile in the PLC modem 26, and notifies the PLC modems 36 and 46 of the profile. . The control circuit 52 of the PLC modems 36 and 46 sets the notified profile in each transmission / reception circuit 56.

  The period during which the power line connection / cutoff circuit 50 graces the connection of the power line is set to a time sufficient to finish changing the profiles of the PLC modems 26, 37, and 46. Thereby, before the transmission characteristic of the power line communication on the power line 10 is actually deteriorated by feeding the electric device 30, the profile of the power line communication can be changed to a profile corresponding to the deterioration of the transmission characteristic. As a result, packet loss and the like can be prevented and communication can be maintained stably.

  In this way, in the first connection, the overall management apparatus 20 searches for a profile according to noise from the connected electrical device 30, but in the second and subsequent connections, the previous search result is used to make an assumption. Profiles prepared for noise and impedance fluctuations can be set, and packet loss can be prevented. In addition, the profile can be quickly changed according to the assumed deterioration of the transmission characteristics, and communication can be continued stably.

  Although general electric equipment has been described as an example, even when power line communication modems having different power line communication standards are connected, the adverse effect can be reduced by the same measures.

  Although the invention has been described with reference to specific illustrative embodiments, various modifications and alterations may be made to the above-described embodiments without departing from the scope of the invention as defined in the claims. This is obvious to an engineer in the field to which the present invention belongs, and such changes and modifications are also included in the technical scope of the present invention.

It is a schematic block diagram of one Example of this invention. It is a figure explaining the relationship between a profile and noise.

Explanation of symbols

10: Power lines 12, 14, 16: Outlet 20: Overall management device 22: Power line 24: Signal line 26: PLC modem 28: Power plug 30: Electrical equipment 32: Power line 34: Signal line 36: PLC modem 38: Power plug 40 : Electric equipment 42: Power line 44: Signal line 46: PLC modem 48: Power plug 50: Power line connection / cutoff circuit 52: Control circuit 54: Memory 56: Transmission / reception circuit

Claims (1)

A power line communication management method in which a general management device manages power line communication conditions by a PLC modem in a power line communication network,
A PLC modem newly connected to the power line communication network transmits an identification signal for identifying an electrical device that communicates using the PLC modem to the overall management device, and feeds the electrical device after a predetermined time;
When the overall management apparatus receives the identification signal, it is a profile indicating power line communication conditions corresponding to fluctuations in transmission characteristics on the power line communication network due to connection of the electric device and noise due to the electric device, Searching for the presence or absence of storing a profile related to identification information;
If the profile related to the identification signal is not stored, the overall management device changes the profile of the power line communication conditions to be used in the power line communication network in accordance with the fluctuation of the transmission characteristics and the noise, Storing the changed profile in association with the identification signal, and notifying the PLC modem constituting the power line communication network of information indicating the changed profile;
A step of notifying the PLC modem configuring the power line communication network of information indicating the stored profile when the overall management apparatus stores the profile related to the identification signal;
And a PLC modem that is notified of information indicating the profile applies the notified profile to itself.

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