JP2010063012A - Power line communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power line communication apparatus with which high-quality communication is maintained. <P>SOLUTION: Steps to be executed by a CPU of a power line communication apparatus include: switching an operational state of the power line communication apparatus from a stopped state to a standby state (S710); determining whether or not the priority and the required number of carriers are received (S720); registering the priority and the required number of carriers received from another power line communication apparatus in a RAM (S730); determining whether or not a preset fixed time has lapsed (S740); acquiring the priority of communication from each of communication signals and calculating the number of carriers required for each communication (S750); calculating bands required for each communication (S760); and notifying each of other power line communication apparatuses of bands available for each communication, respectively (S770). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to communication using a plurality of carriers, and more particularly to a technique for ensuring communication quality.

  In high-speed power line communication, communication is performed using 1,155 carriers at a frequency of 1.8 MHz to 30 MHz in order to transfer data at high speed. However, various devices are connected to the power line, and various noises exist. As a result, the signal may be disturbed and communication may not be performed correctly. Further, for example, when a high priority communication such as VoIP (Voice over Internet Protocol) is performed, if a large amount of low priority communication is performed, the high priority communication is adversely affected. In the case of the VoIP described above, problems such as voice interruption occur.

  Japanese Patent Laid-Open No. 2006-129470 (Patent Document 1) states that “impedance of power line communication between power line communication counterpart devices due to interference from other power line communication systems or other systems or from noise sources is simple and reliable. The power line communication method can be reduced by a certain method to increase not only communication quality and communication reliability but also possible data throughput via the power line communication network (paragraph 0004).

  Japanese Patent Laid-Open No. 2000-165304 (Patent Document 2) discloses a “power line carrier communication apparatus that performs communication control according to a noise environment and an attenuation environment of a power line by superimposing a carrier wave having a plurality of frequency spectra on the power line”. (Paragraph 0001).

  Japanese Patent Application Laid-Open No. 2004-336204 (Patent Document 3) states that “a communication device and a communication system that perform carrier allocation suitable for the data amount of each communication device when a plurality of communication devices perform communication by multi-carrier communication”. (Paragraph 0001).

  JP-T-2004-531944 (Patent Document 4) discloses a technique relating to “a method of multiple access and multiple transmission of data for a multi-user system of point-to-multipoint digital transmission of data via a power line network”. Disclosed (paragraph 0001).

  Japanese Patent Laid-Open No. 2003-018117 (Patent Document 5) discloses a technique relating to “a device that realizes multiple access by adaptively allocating subcarriers to each user in a communication system using OFDM as a modulation scheme”. (Paragraph 0001).

Japanese Unexamined Patent Publication No. 2000-216752 (Patent Document 6) relates to “a multicarrier communication apparatus that performs data communication using a multicarrier modulation / demodulation system, and more particularly, a multicarrier communication apparatus such as a power line modem that performs power line communication using a DMT modulation / demodulation system”. The technology is disclosed (paragraph 0001).
JP 2006-129470 A JP 2000-165304 A JP 2004-336204 A JP-T-2004-531944 JP 2003-018117 A JP 2000-216752 A

  In power line communication, noise on the power line becomes a problem. When there is important communication with high priority, communication may be interrupted due to noise conditions.

  For example, in high-speed power line communication, communication is performed using 1,155 carriers at a frequency of 1.8 MHz to 30 MHz in order to transfer data at high speed. However, information appliances, household appliances, and other devices are connected to the power line, and various noises exist. As a result, the signal may be disturbed and communication may not be performed correctly.

  In addition, it may occur that communication with high priority becomes difficult to transmit because communication with low priority has increased. Since noise on the power line changes from time to time, there is also a problem that communication speed deteriorates.

  Conventionally, there has been no technology for dynamically changing the bandwidth for each communication type. The user of the communication device can change the carrier to be used by manually setting each device, but it cannot be controlled according to the data amount or type. This is because, when communicating with a plurality of communication devices, modulation / demodulation cannot be performed unless the location of the carrier to be used is known.

  Some communications use the 10 to 15 MHz band, but some communications use the 12 to 18 MHz band. If one of the communications is a high-priority communication, the communication with the higher priority is performed in the overlapping band. It will put pressure on quality. Therefore, basically, it is necessary to communicate using the same band for each communication type and the bands do not overlap. In order to change the number of carriers, it is necessary to resolve this synchronization.

  Further, for example, according to the technique disclosed in Japanese Patent Application Laid-Open No. 2004-336204, there is a problem that priority cannot be determined for each communication connection and fine band management cannot be performed.

  According to the technique disclosed in Japanese Translation of PCT International Publication No. 2004-531944, there is a problem that the priority for each communication connection is managed and a bandwidth cannot be finely allocated to each power line communication device.

  According to the technique disclosed in Japanese Patent Laid-Open No. 2003-018117, there is a problem that it is not possible to allocate a band to each power line communication device for each connection. It may also be difficult to synchronize frequency changes.

  According to the technique disclosed in Japanese Patent Laid-Open No. 2000-216752, there is a problem that it is difficult to achieve a synchronization timing for frequency change.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a power line communication apparatus capable of maintaining communication quality. Another object is to provide a method in which the quality of communication using power lines is maintained.

  A power line communication device according to an aspect of the present invention is configured to detect a communication means connected to a communication line and configured to communicate with another power line communication device using a plurality of bands, and a signal transmission state on the communication line. And a communication control unit configured to allocate a dedicated band to the signal based on the transmission state detected by the detection unit.

  Preferably, the detection means is configured to detect the data amount or type of a signal transmitted on the communication line. The communication control means is configured to allocate a dedicated band to the signal according to the data amount or type.

  Preferably, the communication unit transmits control information for allocation of a band used for communication with another power line communication device to another power line communication device using one of the plurality of bands. It is configured to communicate with. The detection means is configured to acquire a signal including information on a band used by another power line communication device. The communication control means is configured to change a band used for communication other than communication by another power line communication device based on information.

  Preferably, the power line communication device further includes a network management unit configured to manage a communication network between the power line communication device and another power line communication device.

  Preferably, the detection means is configured to receive the number of bands used for communication with another power line communication device or the communication priority. The communication control means is configured to allocate a dedicated band for communication with other power line communication devices in accordance with the number of bands or communication priority.

  Preferably, the communication unit is configured to receive the number of bands necessary for communication between the power line communication apparatus and the other power line communication apparatus from the other power line communication apparatus using a predetermined band. Yes. The communication control means is configured to allocate a band different from a predetermined band to communication with another power line communication device based on the number of necessary bands.

  Preferably, the power line communication device further includes a storage unit configured to store predetermined error information or a transfer rate for each band in the communication line. The communication control unit is configured to determine the number of bands necessary for communication between the power line communication device and another power line communication device based on the error information or the transfer rate stored in the storage unit. .

  Preferably, the detection unit is configured to determine whether communication having a priority higher than a predetermined priority has occurred based on a signal received from another power line communication device. The communication control means is configured to preferentially allocate a band to communication having a high priority based on occurrence of communication having a high priority.

  Preferably, the communication control unit is configured to determine a data transfer amount in communication having a high priority, and to allocate a band according to the determined transfer amount.

  Preferably, the communication unit is configured to receive the communication priority and the data transfer amount on the communication line from another power line communication device at predetermined time intervals. The communication control means is configured to secure a band for communication by another power line communication device at predetermined time intervals.

  Preferably, the communication unit is configured to transmit a transmission right permitting communication on the communication line to another power line communication device at predetermined time intervals. The communication control means is configured to allocate a band for communication by the other power line communication device based on a priority or a data transfer amount transmitted by the other power line communication device in response to reception of the transmission right. ing.

  Preferably, the detection unit determines whether or not the number of bands transmitted from another power line communication device as the number of bands necessary for communication using the communication line exceeds the number of bands assigned to the other power line communication device. It is configured to determine. When the number of bands transmitted from another power line communication device as the number of bands necessary for communication using the communication line exceeds the number of bands assigned to the other power line communication device, the communication control means A band is reassigned to each communication according to the priority of each communication.

  Preferably, the communication control means is configured to release a band assigned to communication having a low priority and assign the band to communication having a high priority.

  Preferably, the power line communication apparatus determines the number of carriers necessary for communication based on the storage means configured to store noise information prepared in advance as noise information of each band in the communication line, and the noise information. And a determination means configured as described above. The communication control means is configured to allocate a band to communication based on the number of carriers determined by the determination means.

  Preferably, the power line communication device further includes storage means configured to store noise information of each band in the communication line. The detection means is configured to acquire the priority of communication by the other power line communication device based on the signal received from the other power line communication device. The communication control unit is configured to allocate communication by another power line communication device to a band with less noise among a plurality of bands of the communication line according to the acquired priority.

  Preferably, when the power line communication device communicates with a plurality of other power line communication devices, the communication control means assigns communication by each other power line communication device to each band in descending order of priority, and The configuration is such that the band noise is performed in ascending order.

  Preferably, the communication control means is configured to assign a communication with a high priority to a band in which a noise level is lower than a preset reference.

  Preferably, the power line communication device further includes update means configured to update noise information stored in the storage means before assigning communication to a plurality of bands of the communication line.

  According to the present invention, it is possible to prevent a reduction in communication quality in communication using a power line.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated. Further, in the case where different embodiments are described, the description of the configuration according to the embodiment will not be repeated except for the configuration unique to the embodiment.

<First Embodiment>
[Technology]
First, the technical idea of the power line communication device according to the embodiment of the present invention will be described. First, in general, in power line communication, there is a power line communication device (CCo, also referred to as “master”) that always manages the network. The CCo manages other power line communication devices (STA, also referred to as “slave”) on the network. When the power of CCo is turned off, other STAs function as CCo. Thus, one CCo always exists on the power line communication network. The CCo manages the band (channel) that can be used by each power line communication device and notifies other STAs of the band to be used, thereby avoiding the use of a noisy channel or preferentially controlling the channel. Can be assigned to improve communication quality. In the present embodiment, the control channel refers to a channel used for band synchronization between the power line communication devices and other management.

  Each power line communication device (STA, CCo) periodically notifies CCo of the number of carriers necessary for each communication according to the amount of data sent to itself and the communication type. The CCo will send the number of carriers to itself.

  The CCo calculates the total value of the number of carriers from each power line communication device, and determines a carrier that can actually be used for communication. The CCo notifies each power line communication device of the carrier to be used, and each power line communication device performs modulation / demodulation using the carrier. CCo refers to an information table including error information (S / N (Signal to Noise) level) of each band, and exclusively allocates communication with high priority to a band with less noise.

  In this way, the bandwidth used by high-priority communication is secured, so even if low-priority communication suddenly increases, high-priority communication communicates stably using a dedicated carrier. can do. In addition, since the CCo manages the carrier used by each power line communication device, control complexity can be avoided.

  That is, by combining a virtual master called CCo, frequency control, and noise information (S / N table (referred to as channel evaluation in power line communication)), communication quality (QoS) can be improved.

[System configuration]
First, the power line communication system 100 will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of a power line communication system 100 according to an embodiment of the present invention.

  The power line communication system 100 includes a power line communication device 102, a terminal 120 connected to the power line communication device 102 via a cable 150, a power line communication device 104, a terminal 130 connected to the power line communication device 104 via a cable 151, and a power line communication. Device 106 and terminal 140 connected to the power line communication device by cable 152 are provided.

  The terminals 120, 130, and 140 are, for example, PCs (Personal Computers), IP (Internet Protocol) phones, televisions with network communication functions, door phones, and the like.

  The cables 150, 151, and 152 are media for transmitting signals in accordance with, for example, the Ethernet (registered trademark) standard, but the transmission standard is not limited thereto. Further, a wireless connection may be used instead of the cables 150, 151, and 152. The wireless connection transmission format is, for example, Bluetooth or the like, but is not limited thereto.

  The power line communication devices 102, 104, and 106 are connected to the power line 110 via plugs 112, 114, and 116 by plugs 103, 105, and 107, respectively.

  The power line communication devices 102, 104, and 106 function as so-called PLC (Power Line Communication) adapters. Specifically, power line communication apparatuses 102, 104, and 106 mutually convert a signal transmitted between each terminal and each power line communication apparatus and a power line communication signal (hereinafter also referred to as “PLC signal”).

  The power line communication devices 102, 104 and 106 communicate via the power line 110. On the power line 110, data is transmitted by a plurality of carriers (carrier waves). Each of the power line communication devices 102, 104, and 106 has a function for controlling a carrier used for communication, as will be described later. Here, the carrier control may include carrier selection, allocation, reallocation, and the like.

  One of the power line communication devices 102, 104, 106 is a so-called master (CCo: Central Coordinator), and the remaining power line communication devices are so-called slave devices (STA: Station). For example, in HomePlugAV, which is one of the power line communication standards, the first activated device among the power line communication devices connected to the same power line functions as a master. In the present embodiment, power line communication apparatus 102 will be described as being activated first and functioning as a master.

  In addition, when the power supply of the power line communication apparatus 102 functioning as the master is cut off, one of the other power line communication apparatuses 104 and 106 functions as the master. For example, the remaining power line communication devices 104 and 106 may be configured such that the device having the smallest identification number functions as a master by exchanging identification data with each other. Alternatively, a power line communication device that is not communicating with a connected terminal may function as a master. In this case, since the setting for functioning as a master is not hindered by communication with the terminal, the occurrence of an erroneous operation can be prevented. However, the determination method of the power line communication device functioning as the master differs depending on the implementation, and is not limited to the above.

  In the present embodiment, among the power line communication devices, the power line communication device that functions as a master functions as a “communication management device” that is a main entity that manages power line communication. The master determines a carrier necessary for power line communication and gives an instruction to each power line communication device to perform communication using the determined carrier. Note that “each power line communication device” includes the master itself.

[Hardware configuration]
With reference to FIG. 2, a specific configuration of power line communication apparatuses 102, 104, and 106 will be described. FIG. 2 is a block diagram illustrating a hardware configuration of the power line communication apparatus 102. The power line communication devices 104 and 106 are also realized by the same hardware configuration. The difference between the master and the slave of the power line communication device is based on, for example, whether or not the power line communication device causes the function for realizing the processing as the master to be executed by software.

  The power line communication apparatus 102 includes a CPU (Central Processing Unit) 210, a PLC modem 212, an analog front end 214, a transformer 216, a plug 103, a low-pass filter 220, a service outlet 222, an insertion detection unit 224, AC-DC (Alternating Current-Direct Current) power converter 226, RAM (Random Access Memory) 228, flash ROM (Read Only Memory) 230, Ethernet (registered trademark) controller 232, RJ45 connector 234, LED (Light Emitting Diode) 236, a speaker 238, and an operation panel 240. The terminal 120 and other information communication devices can be connected to the RJ45 connector 234. A power plug of a PC or other communication terminal device can be connected to the service outlet 222.

  The CPU 210 controls the operation of the power line communication apparatus 102 based on a command given to the power line communication apparatus 102 and data and programs stored in the power line communication apparatus 102. More specifically, the CPU 210 executes a command based on data stored in the RAM 228 and the flash ROM 230 and a program stored in the flash ROM 230, and controls communication according to the command.

  The PLC modem 212 converts data generated by the CPU 210 or data acquired via the Ethernet (registered trademark) controller 232 into a format for power line communication, and outputs the converted data to the analog front end 214. In addition, the PLC modem 212 extracts data from the signal acquired from the power line via the plug 103 and transmits the acquired data to the CPU 210.

  The analog front end 214 converts digital data output from the PLC modem 212 into an analog signal, and transmits the analog signal generated by the conversion to the transformer 216. Conversely, the analog front end 214 converts the analog signal output from the transformer 216 into digital data, and sends the digital data generated by the conversion to the PLC modem 212.

  The transformer 216 superimposes the analog signal from the analog front end 214 on the power line. The transformer 216 extracts a signal on the power line and transmits the extracted signal to the analog front end 214. The plug 103 is connected to an outlet 112 provided on a wall of a room where the power line communication device 102 is installed, and receives power from the power line 110.

  The low pass filter 220 removes the signal. The operation of the low-pass filter 220 is disabled while the setting information is not transmitted. This switching is performed according to a command from CPU 210, for example.

  Service outlet 222 accepts insertion of a power plug of another device (for example, IP telephone, terminal 120, etc.) that receives power supply from power line communication device 102. The insertion detection unit 224 detects that another plug has been inserted into the service outlet 222. The insertion detection unit 224 sends a signal represented by the detection to the CPU 210. Service outlet 222 and insertion detection unit 224 are not essential components for power line communication apparatus 102 according to the present embodiment.

  The AC-DC power supply conversion unit 226 converts the AC power supplied to the power line communication apparatus 102 into a DC power supply, and supplies the DC current to hardware configuring the power line communication apparatus 102.

  The RAM 228 temporarily stores data generated by the CPU 210. The RAM 228 also stores data acquired from the outside by the Ethernet (registered trademark) controller 232.

  The flash ROM 230 stores data and programs prepared in advance by the manufacturer of the power line communication device 102. Further, the flash ROM 230 also stores data acquired by communication of the power line communication device 102 by the writing operation of the CPU 210.

  The Ethernet (registered trademark) controller 232 controls communication between the power line communication apparatus 102 and the terminal 120 connected to the RJ45 connector 234 in accordance with a command output from the CPU 210. The Ethernet (registered trademark) controller 232 reads the data stored in the RAM 228 and sends the data to the RJ45 connector 234. When the power line communication apparatus 102 receives data sent from the terminal 120, the Ethernet (registered trademark) controller 232 writes the data sent from the RJ45 connector 234 in an area secured in the RAM 228. The CPU 210 reads the written data with reference to the RAM 228 in response to the write completion interrupt signal.

  The RJ45 connector 234 accepts attachment of a cable connected to the terminal 120 and other information communication devices.

  The LED 236 performs a predetermined lighting operation or blinking operation in accordance with a light emission command output from the CPU 210. For example, the LED 236 transmits a signal indicating the operation state of the power line communication device 102 (normal communication, setting information communication, and pairing with another communication terminal). The user of the power line communication apparatus 102 can recognize the operation state of the power line communication apparatus 102 based on the lighting or blinking state.

  The speaker 238 outputs a predetermined sound for notifying the operation of the power line communication apparatus 102 in accordance with a signal output from the CPU 210. For example, when an abnormality is detected in the power line communication apparatus 102, the speaker 238 can emit a buzzer that notifies the abnormality.

  Operation panel 240 accepts input of settings for power line communication apparatus 102. For example, the setting for permitting or prohibiting transmission of setting information by the power line communication apparatus 102 is realized according to an operation on the operation panel 240. Further, when the user wants to forcibly execute the operation of the low-pass filter 220, the operation is forcibly switched according to the operation on the operation panel 240. In this case, the command output from the CPU 210 is invalidated. The operation panel 240 is realized by a touch panel, a toggle switch, or the like. Alternatively, a photoelectric conversion element may be used. In this case, instead of an operation by the user of the power line communication apparatus 102, the light defines an operation input.

[Information communication mode]
With reference to FIG. 3, the exchange of information between the power line communication apparatuses when determining the communication carrier will be described. FIG. 3 is a diagram showing a communication mode of information in power line communication system 100 according to the embodiment of the present invention.

  The power line communication apparatus 104 that is a slave apparatus (STA) transmits a message 320 that conveys the required number of carriers calculated based on the amount of transferred data that flows into the power line communication apparatus 102 that is the master (CCo). Similarly, the power line communication apparatus 106 transmits a message 310 that tells the required number of carriers to the power line communication apparatus 102. The power line communication device 102 transmits a similar message to itself.

  Each of the power line communication apparatuses 102, 104, and 106 transmits the message toward the power line communication apparatus 102 at a predetermined timing. For example, the power line communication apparatuses 102, 104, and 106 transmit the message to the power line communication apparatus 102 at regular time intervals. In this case, each of the power line communication apparatuses 102, 104, and 106 may transmit a message notifying the maximum number of necessary carriers calculated within the certain time interval to the power line communication apparatus 102. By doing so, communication can be reliably ensured.

  Alternatively, each of the power line communication apparatuses 102, 104, and 106 may transmit a message when the amount of data monitored inside or the amount of change in transfer rate exceeds a preset threshold value. For example, the CPU 210 may be configured to calculate a change amount based on the monitored data amount or transfer rate, and generate and transmit a message when the change amount exceeds a threshold value. According to such a configuration, since the number of times of transmitting a message can be reduced, the load on the communication network is reduced.

  When the power line communication apparatus 102 as a master receives a message indicating the required number of carriers from each power line communication apparatus, the power line communication apparatus 102 determines a carrier (hereinafter referred to as “communication carrier”) that can be used for communication based on the required number of carriers. . And the instruction | command 330 which requests | requires the setting which communicates with a communication carrier is transmitted to the power line communication apparatus which transmitted the required number of carriers.

  The power line communication apparatus 102 transmits the command 330 at a predetermined timing. Specifically, the power line communication apparatus 102 transmits the command 330 at a constant time interval, for example. Alternatively, each time the power line communication apparatus 102 determines a communication carrier in response to reception of the required number of carriers, the power line communication apparatus 102 may immediately transmit the instruction 330 (without waiting time).

  Power line communication apparatuses 102, 104, and 106 according to the present embodiment can determine a communication carrier according to the amount of transfer data, and can dynamically change the communication carrier according to the communication state. Therefore, communication carrier interference required by each power line communication device can be prevented, and communication quality deterioration due to communication congestion or noise can be prevented. Moreover, since it is possible to prevent the use of more carriers than necessary, it is possible to reduce power consumption in power line communication. In particular, if this power line communication device is introduced into a network including many communication devices having a long standby state, power consumption can be dramatically reduced.

  Then, with reference to FIG. 4, the determination of the communication carrier in the power line communication system which concerns on this Embodiment is demonstrated. FIG. 4 is a diagram conceptually showing the relationship between the transfer data amount and the carrier used for power line communication.

  FIG. 4A shows the relationship between the transfer data amount and the carrier in the conventional power line communication. As shown in FIG. 4A, power line communication is always performed with the maximum number of carriers 401 regardless of the amount of transfer data. Therefore, according to this communication method, even when data transmission is not performed, communication is performed using a large number of carriers other than the minimum control channel 400 necessary for communication between power line communication apparatuses. Become. As a result, the carrier operating rate (usage rate) in this case is low.

  FIG. 4B and FIG. 4C each show the relationship between the amount of transferred data and the number of carriers when the power line communication apparatus according to the present embodiment is used. FIG. 4B shows the relationship when the amount of transfer data is small. Carriers used for communication include a control channel 400, a carrier 402 for transmitting low priority data, and a carrier 410 for transmitting high priority data. Here, the number of carriers 402 is allocated smaller than the case where the amount of transfer data is large or smaller than the maximum number of carriers, depending on the small amount of transfer data. As a result, the number of carriers used as a whole is also reduced.

  On the other hand, FIG. 4C shows the relationship when the amount of transfer data is large. Carriers used for communication include a control channel 400, a carrier 403, and a carrier 410. The number of carriers 403 is allocated according to the transfer data amount. Since the carrier 410 has a high priority, the assignment does not change. Note that, when the carrier 403 is allocated, if there are not enough carriers that can be allocated, the priority of each communication using the carrier other than the carrier 410 is determined, and the priority of the communication using the carrier 403 is determined for other communication. When the priority is exceeded, the carrier assigned to the other communication may be included in the carrier 403. Even in this case, since the carrier 410 is reliably maintained, the communication quality with high priority can be maintained.

  Thus, according to the power line communication apparatus according to the present embodiment, the number of carriers used for communication is changed according to the amount of transfer data. Therefore, since it becomes easy to secure an empty carrier, an empty carrier can be allocated to other communications in which a larger amount of data is transmitted. As a result, it becomes easy to change the carrier allocation among a plurality of communications, and it becomes easy to prevent the transmission data amount or noise caused by the lack of bandwidth, thereby preventing the communication quality from deteriorating.

[Function configuration]
With reference to FIG. 5, the configuration of the power line communication apparatus according to the present embodiment will be further described. FIG. 5 is a block diagram showing a configuration of functions realized by each of power line communication apparatuses 102, 104, and 106. The power line communication apparatus 102 includes a communication unit 510, a detection unit 520, a communication control unit 530, and a network management unit 540.

  Communication unit 510 is connected to a communication line and configured to communicate with other power line communication devices using a plurality of bands. The detection unit 520 is configured to detect a signal transmission state in the communication line. Preferably, the detection unit 520 is configured to detect the data amount or type or priority of a signal transmitted on the communication line. The communication control unit 530 is configured to allocate a dedicated band to the signal based on the transmission state detected by the detection unit 520. Preferably, the communication control unit 530 is configured to exclusively allocate a band to the signal according to the data amount, type, or priority.

  In another aspect, communication unit 510 uses one band among a plurality of bands to transmit control information for allocation of a band used for communication with another power line communication apparatus to another power line communication apparatus. Are configured to communicate with each other. The detection unit 520 is configured to acquire a signal including information on a band used by another power line communication device. The communication control unit 530 is configured to change a band used for communication other than communication by another power line communication device based on the information.

  The network management unit 540 is configured to manage a communication network between the power line communication device 102 and another power line communication device. By functioning the network management unit 540, the power line communication device 102 can function as a so-called master (or as a CCo (Central Coordinator)) in the power line communication network.

  Preferably, communication unit 510 is configured to receive the number of bands or communication priority used for communication with other power line communication devices. The communication control unit 530 is configured to allocate a dedicated band for communication with other power line communication apparatuses according to the number of bands or communication priority.

  Preferably, communication unit 510 receives the number of bands necessary for communication between another power line communication apparatus and power line communication apparatus 102 from another power line communication apparatus using a predetermined band. It is configured. The communication control unit 530 is configured to allocate a band different from the predetermined band for communication with other power line communication devices based on the number of necessary bands.

  Preferably, detection unit 520 is configured to acquire the priority of communication by another power line communication device based on a signal received from another power line communication device. The communication control unit 530 is configured to allocate communication by another power line communication device to a band with less noise among a plurality of bands of the communication line according to the acquired priority.

[Control structure]
A control structure of the power line communication apparatus will be described with reference to FIG. FIG. 6 is a flowchart showing a part of a series of operations executed by CPU 210 of power line communication apparatuses 104 and 106 functioning as slaves.

  In step S610, CPU 210 switches the operation state to the standby state based on the fact that the power switch is turned on by an operation on operation panel 240.

  In step S620, CPU 210 determines whether or not a predetermined time has elapsed. For example, the CPU 210 measures time based on a clocking function that the CPU 210 has. Alternatively, the CPU 210 detects the passage of time based on the value of the counter that starts measuring in response to the power switch being set to ON. When CPU 210 determines that the predetermined time has elapsed (YES in step S620), CPU 210 switches control to step S630. If not (NO in step S620), CPU 210 returns control to step S610 and continues the standby state.

  In step S630, CPU 210 obtains a communication priority (also referred to as “packet priority”) from a signal (packet) received by PLC modem 212, for example, in communication I / F (interface). The amount of data transmitted from the signal is acquired. The priority can be obtained, for example, by decoding a TOS (Type of Service) field in a packet header or a DSCP (Differentiated Services Code Point). Further, the CPU 210 calculates a data transfer rate.

  In step S640, CPU 210 calculates the number of carriers (number of bands) necessary for communication for each priority. One aspect of calculation will be described for the case of HomePlugAV. In the case of power line communication using HomePluAV as a communication standard, data transfer of about 200 kbps per carrier is possible. Therefore, for example, when a speed of about 10 Mbps is required, the CPU 210 calculates (10 Mbps ÷ 200 kbps =) 50 carriers as the number of carriers necessary for the communication.

  In step S650, power line communication apparatus 104 notifies power line communication apparatus 102 functioning as a master (CCo) of the priority and the required number of carriers.

  In the above description, the case where the power line communication devices 104 and 106 functioning as slaves notify the power line communication device 102 functioning as a master of the priority and the number of carriers has been described. Similarly, the power line communication apparatus 102 functioning as a master may acquire the priority of its own communication, calculate the number of carriers, and notify the priority and the number of carriers to itself. Thereby, the power line communication apparatus 102 can also secure a carrier necessary for communication.

[Master control structure]
FIG. 7 is a flowchart showing a part of a series of operations executed by power line communication apparatus 102 functioning as a master (CCo).

  In step S710, CPU 210 of power line communication apparatus 102 switches its operation state from a stopped state to a standby state based on an operation on operation panel 240 serving as a power switch. Note that this processing is not necessary when the power supply of the power line communication apparatus 102 is always set to ON.

  In step S720, CPU 210 determines whether or not the priority and the necessary number of carriers have been received based on a signal received from the outside. This determination is performed, for example, by the CPU 210 extracting a data item included in the signal. When CPU 210 determines that the priority and the necessary number of carriers have been received (YES in step S720), CPU 210 switches control to step S730. If not (NO in step S720), CPU 210 switches control to step S740.

  In step S730, CPU 210 registers the priority received from other power line communication apparatuses 104 and 106 and the necessary number of carriers in RAM 228. The RAM 228 holds the communication by each power line communication device, the priority of the communication, and the necessary number of carriers in association with each other.

  In step S740, CPU 210 determines whether or not a predetermined time has elapsed. This determination is performed based on the time measuring function of CPU 210 or the value of the counter, similarly to the determination in power line communication apparatus 104 described above. When CPU 210 determines that the predetermined time has elapsed (YES in step S740), CPU 210 switches control to step S750. If not (NO in step S740), CPU 210 returns control to step S710 and continues the standby state.

  In step S750, CPU 210 obtains the priority of communication by power line communication apparatus 102 itself from each communication signal, and calculates the number of carriers necessary for each communication. The acquisition of the priority and the calculation of the number of carriers are executed in the same manner as the processing in steps S630 and S640.

  In step S760, CPU 210 calculates a bandwidth necessary for each communication based on the acquired priority and the calculated number of carriers. For example, first, the CPU 210 calculates the necessary number of carriers from communication with high priority. There may be a case where the number of carriers required for all communications is secured, and there is a case where band allocation has already been lost for communications with low priority. At least, a carrier necessary for high priority communication is surely assigned.

  In step S770, power line communication apparatus 102 notifies other power line communication apparatuses 104 and 106 of a band that can be used for each communication. Each power line communication apparatus can synchronize the band information to be used, and communicates using the band allocated to each. Thus, for example, in a home network, low priority communication such as transfer of recorded video may be temporarily interrupted, but IP telephone communication is ensured as an example of high priority communication. Therefore, the communication quality can be prevented from deteriorating.

  In other aspects, when all available bandwidth is used, or when there is a request for carrier allocation by newly generated communication with high priority communication, power line communication that functions as a master Device 102 can also reduce the number of carriers assigned to low priority communications and assign the carriers to the newly generated communications.

  As described above, the power line communication apparatus according to the first embodiment of the present invention obtains the priority from the transmitted signal and calculates the necessary number of carriers from the data amount. Further, the power line communication device assigns communication to each power line communication device constituting the power line communication network based on the priority and the number of carriers. Each power line communication apparatus communicates using the assigned carrier. In this way, since the carrier assignment for the high priority communication is performed in preference to the carrier assignment for the low priority communication, the high priority communication is prevented from being interrupted. Thereby, communication quality can be ensured.

<Modification>
A modification of the present embodiment will be described with reference to FIG. FIG. 8 is a block diagram illustrating a configuration of functions realized by power line communication apparatus 102 according to the modification of the first embodiment. The power line communication apparatus 102 according to the present modification further includes a storage unit 810 and a determination unit 820 in addition to the above-described configuration.

  The storage unit 810 is configured to store noise information prepared in advance as noise information of each band in the communication line. The determining unit 820 is configured to determine the number of carriers necessary for communication based on the noise information. The communication control unit 530 is configured to allocate a band to the communication based on the number of carriers determined by the determination unit 820.

  Preferably, when the power line communication device is communicating with a plurality of other power line communication devices, the communication control unit 530 assigns communication by the other power line communication devices to each band in descending order of priority, and The band noise is configured in ascending order of noise.

  In another aspect, the communication control unit 530 may assign high priority communication to a band in which the noise level is lower than a preset reference.

[data structure]
With reference to FIG. 9, a data structure of power line communication apparatus 102 according to the present modification will be described. FIG. 9 is a diagram conceptually showing the configuration of the table stored in storage unit 810. The storage unit 810 stores a number 910 for identifying a carrier, an S / N (Signal to Noise) 920, a transmission gain 930, a reception gain 940, a modulation scheme 950 in the carrier, and an error rate 960. is doing.

  The S / N 920, the transmission gain 930, and the reception gain 940 are measured by the network builder when the communication network is constructed, and are input to the storage unit 810. The modulation method 950 is input by the builder when the network is constructed or designated by the communication control unit 530. The error rate 960 is measured by, for example, trial communication performed after the communication network including the power line communication apparatus 102 is constructed, and the measurement result is stored in the storage unit 810 as the error rate 960.

  When the power line communication apparatus 102 according to the present modification functions as a master, the power line communication apparatus 102 determines a carrier with reference to the table shown in FIG. For example, the CPU 210 allocates a band with less noise in descending order of communication priority. Alternatively, the CPU 210 assigns a carrier with a low error rate. Thereby, deterioration of the quality of communication with high priority can be prevented.

  In addition, since communication for carrier allocation is not performed in this way, the amount of actual data transmitted in the network can be reduced. In addition, the load on the CPU 210 of each power line communication device can be reduced.

<Second Embodiment>
Hereinafter, a second embodiment of the present invention will be described. The power line communication device according to the present embodiment maintains the communication quality with a high priority corresponding to the point that the transmission right is given to another power line communication device and the other power line communication device holds the transmission right. It differs from the first embodiment in that it has a function. According to the power line communication system having the power line communication device according to the present embodiment, the transmission right of the message is relayed between the power line communication devices, and the power line communication device that has received the transmission right can transmit the message.

  The hardware configuration of the power line communication apparatus according to the present embodiment is the same as the hardware configuration of the power line communication apparatus according to the first embodiment described above. Therefore, the description of the hardware configuration will not be repeated.

  According to the present embodiment, for example, CPU 210 of power line communication apparatus 102 functioning as a master generates a signal indicating transmission right (hereinafter simply referred to as “transmission right”) as communication control unit 530. The power line communication apparatus 102 first assigns a carrier for communication by another power line communication apparatus, and then transmits a transmission right to one of the other power line communication apparatuses 104 and 106 functioning as a slave. Here, the transmission order of the transmission right follows the order registered in the master as a slave, for example. Alternatively, when a management number is set by a system builder or administrator at the time of construction of the power line communication system, the management numbers may be in ascending order or descending order.

[Control structure]
Next, with reference to FIG. 10 and FIG. 11, the control structure of the power line communication apparatus according to the present embodiment will be described. FIG. 10 is a flowchart showing a part of a series of operations executed by power line communication apparatus 102. Note that the same step numbers are assigned to the same processes as those in the first embodiment described above. Therefore, those descriptions will not be repeated. Hereinafter, a case where the transmission right is transferred from the power line communication apparatus 102 to the power line communication apparatus 104 will be described. In this case, even if the power line communication device 106 detects reception of a signal including a transmission right, the power line communication device 106 ignores the signal because it is not a signal for itself.

  In step S1010, each CPU 210 of power line communication apparatuses 104 and 106 determines whether a transmission right has been acquired based on information received from the outside. For example, the power line communication device 104 determines whether or not the information received from the outside has an identification number of the power line communication device and a control code representing a transmission right. When CPU 210 determines that the transmission right has been acquired (YES in step S1010), CPU 210 switches control to step S630. If not (NO in step S1010), CPU 210 returns control to step S610 and continues the standby state.

  In step S1020, CPU 210 calculates the number of carriers necessary for each connection. Here, the connection refers to each communication performed by the power line communication device 104. For example, when different communications are performed between the same two power line communication devices, a separate connection is specified for each communication.

  In step S1030, CPU 210 confirms the noise table (FIG. 9) stored in storage unit 810, and determines a bandwidth to be allocated for each connection based on the table. CPU 210 notifies other power line communication apparatuses 102 and 106 of the determined bandwidth. The determination of the band to be allocated is based on, for example, the priority for each connection, the noise information of each carrier, the amount of data transmitted in each connection, and the like. The power line communication device 104 communicates with the other power line communication devices 102 and 106 using the notified band.

  A detailed example of assignment is as follows. For example, when the power line communication device 102 (master) and the power line communication device 106 are performing high-priority communication, the CPU 210 of the power line communication device 104 allocates a 15 MHz to 17 MHz band with less noise to the communication. On the other hand, when the power line communication apparatus 102 and the power line communication apparatus 104 are performing low-priority communication, the CPU 210 of the power line communication apparatus 104 allocates a band of 2 MHz to 8 MHz with relatively noise to the communication. In this case, the power line communication apparatus 102 uses 2 MHz to 8 MHz and 15 MHz to 17 MHz. The power line communication device 104 uses 2 MHz to 8 MHz. The power line communication device 106 uses 15 MHz to 17 MHz.

  In step S1040, CPU 210 waits for a preset time, and then relays the transmission right to the next power line communication device 106. Specifically, CPU 210 transmits a signal including a transmission right and identification data of power line communication device 106. In this case, even if the power line communication apparatus 102 receives this signal, the identification data does not match, so this signal is ignored.

[Control structure of power line communication equipment without transmission right]
FIG. 11 is a flowchart showing a part of a series of operations executed by a power line communication apparatus (for example, power line communication apparatuses 102 and 106) that does not have a transmission right. The same steps as those shown in FIG. 7 are denoted by the same step numbers, and the description of the processing will not be repeated.

  In step S1110, each CPU 210 of power line communication apparatuses 102 and 106 determines whether or not band information indicating a band that can be used for communication has been received from information received from power line communication apparatus 104. This determination is performed, for example, by determining whether or not the received information includes a code indicating the notification of the band and data for identifying the band. If each CPU 210 determines that the band information has been received (YES in step S1110), the control is switched to step S1120. If not (NO in step S1110), CPU 210 returns control to step S710 and continues the standby state.

  In step S1120, CPU 210 registers the notified band in RAM 228, and communicates with another power line communication device via communication unit 510 using the band.

  As described above, when the power line communication device according to the second embodiment of the present invention has the transmission right, the power line communication device determines the allocation of the band and assigns the band to other power line communication devices that do not have the transmission right. Notice. Transmission rights are relayed, for example, in the order registered in the power line communication network and in the order of identification numbers of the power line communication devices. In this way, each power line communication device can execute a process of securing a bandwidth for communication, so that communication is performed fairly. In addition, since band allocation can be performed by a power line communication apparatus other than the power line communication apparatus functioning as a master, the degree of freedom of band management and allocation is increased, and high-quality communication can be maintained.

<Modification>
Hereinafter, modifications of the above-described embodiments will be described. The power line communication device according to the present modification is different from the power line communication device according to the above-described embodiment in that it has a function of updating information stored in the storage unit 810.

[Function configuration]
Then, with reference to FIG. 12, the structure of the power line communication apparatus 1200 which concerns on this Embodiment is demonstrated. FIG. 12 is a block diagram showing a configuration of functions realized by power line communication apparatus 1200. The power line communication apparatus 1200 further includes an input unit 1210 and an update unit 1220 in addition to the configuration shown in FIG.

  Input unit 1210 is configured to receive input of data or instructions to power line communication apparatus 1200. The update unit 1220 is configured to update the noise information stored in the storage unit 810 before allocating communication to a plurality of bands of the communication line.

  Input unit 1210 accepts data input or command input to power line communication apparatus 1200. The input unit 1210 is realized by, for example, a USB (Universal Serial Bus) interface.

  The update unit 1220 writes the data received by the input unit 1210 in the storage unit 810. Update unit 1220 is implemented by, for example, CPU 210 or another processor. When the update unit 1220 updates the data, the noise information of each carrier shown in FIG. 9 is updated. Thereby, the noise information in the communication network using the power line communication device can be easily updated.

[Effect of the embodiment]
As described above in detail, the power line communication devices according to the first and second embodiments and the modifications of the present invention can be obtained by assigning carriers according to the priority of communication between the power line communication devices. High quality communication can be performed. For example, communication with high priority such as VoIP can be assigned a band (channel) with less noise. Other communications with lower priority receive the remaining carrier allocation. In this way, even when other communications suddenly increase, at least VoIP communications can stably transmit signals with high quality.

  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 description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a block diagram showing a configuration of a power line communication system 100 according to a first embodiment of the present invention. 2 is a block diagram illustrating a hardware configuration of power line communication apparatuses 102, 104, and 106. FIG. It is a figure showing the communication mode of the information in the power line communication system 100 which concerns on embodiment of this invention. It is a figure which represents notionally the relationship between the amount of transfer data, and the carrier used for power line communication. FIG. 5 is a block diagram showing a configuration of functions realized by each of power line communication apparatuses 102, 104, and 106. It is a flowchart showing a part of a series of operation | movement which CPU210 of the power line communication apparatuses 104 and 106 which function as a slave performs. It is a flowchart showing a part of a series of operation | movement which CPU210 of the power line communication apparatus 102 which functions as a master (CCo) performs. It is a block diagram showing the structure of the function implement | achieved by the power line communication apparatus 102 which concerns on the modification of 1st Embodiment. It is a figure which represents notionally the structure of the table stored in the memory | storage part 810 of the power line communication apparatus 102 which concerns on the modification of 1st Embodiment. It is a flowchart showing a part of a series of operation | movement which CPU210 of the power line communication apparatus 102 which concerns on the 2nd Embodiment of this invention performs. It is a flowchart showing a part of a series of operation | movement which CPU210 of the power line communication apparatus which does not have a transmission right. It is a block diagram showing the structure of the function implement | achieved by the power line communication apparatus 1200 which concerns on the modification of embodiment of this invention.

Explanation of symbols

  100 power line communication system, 102, 104, 106 power line communication device, 103, 105, 107 plug, 110 power line, 112, 114, 116 outlet, 120, 130, 140 terminal, 310, 320 message, 330 command, 400 control channel, 401, 402, 403, 410 Carrier.

Claims (18)

A power line communication device,
A communication means connected to the communication line and configured to communicate with other power line communication devices using a plurality of bands;
Detecting means configured to detect a transmission state of a signal in the communication line;
A power line communication apparatus comprising: a communication control unit configured to allocate a dedicated band to the signal based on a transmission state detected by the detection unit. The detection means is configured to detect a data amount or type of a signal transmitted in the communication line,
The power line communication device according to claim 1, wherein the communication control unit is configured to allocate a dedicated band to the signal according to the data amount or type. The communication means uses one of the plurality of bands to transmit control information for allocation of a band used for communication with the other power line communication device to the other power line communication device. Are configured to communicate between each other,
The detection means is configured to acquire a signal including information on a band used by the other power line communication device,
The power line communication according to claim 1, wherein the communication control unit is configured to change a band used for communication other than communication by the other power line communication device based on the information. apparatus.   The power line communication apparatus according to any one of claims 1 to 3, further comprising a network management unit configured to manage a communication network between the power line communication apparatus and the other power line communication apparatus. The detection means is configured to receive the number of bands used for communication with the other power line communication device or the communication priority.
The communication control means is configured to allocate a dedicated band for communication with the other power line communication device in accordance with the number of bands or communication priority. A power line communication apparatus according to claim 1. The communication unit is configured to receive the number of bands necessary for communication between the power line communication apparatus and the other power line communication apparatus from the other power line communication apparatus using a predetermined band. And
The communication control unit is configured to allocate a band different from the predetermined band to communication with the other power line communication device based on the required number of bands. Item 6. The power line communication device according to any one of Items 5 to 6. Storage means configured to store predefined error information or transfer rate for each band in the communication line;
The communication control unit determines the number of bands necessary for communication between the power line communication device and the other power line communication device based on error information or a transfer rate stored in the storage unit. The power line communication device according to any one of claims 1 to 5, wherein the power line communication device is configured. The detection means is configured to determine whether communication having a priority higher than a predetermined priority has occurred based on a signal received from the other power line communication device,
The communication control means is configured to preferentially allocate a band to the communication having the high priority based on the occurrence of the communication having the high priority. Item 8. The power line communication device according to any one of Items 7 to 9.   The power line communication device according to claim 8, wherein the communication control unit is configured to determine a data transfer amount in the communication having the high priority, and to allocate a band according to the determined transfer amount. . The communication means is configured to receive the communication priority and the data transfer amount in the communication line from the other power line communication device every predetermined time,
The power line communication device according to claim 8, wherein the communication control unit is configured to secure a band for communication by the other power line communication device at each predetermined time. The communication means is configured to transmit a transmission right permitting communication on the communication line to the other power line communication device at predetermined time intervals,
The communication control unit allocates a band for communication by the other power line communication device based on a priority or a data transfer amount transmitted by the other power line communication device in response to reception of the transmission right. The power line communication apparatus according to claim 1, configured as described above. The detecting means determines whether the number of bands transmitted from the other power line communication device as the number of bands necessary for communication using the communication line exceeds the number of bands assigned to the other power line communication device. Is configured to determine,
The communication control means, when the number of bands sent from the other power line communication device as the number of bands necessary for communication using the communication line exceeds the number of bands assigned to the other power line communication device The power line communication device according to claim 1, wherein the power line communication device is configured to reallocate a band to each of the communication according to a priority of each communication in the communication line.   The power line communication device according to claim 12, wherein the communication control unit is configured to release a band assigned to communication with low priority and assign the band to communication with high priority. Storage means configured to store noise information prepared in advance as noise information of each band in the communication line;
Determining means configured to determine the number of carriers required for communication based on the noise information;
The power line communication device according to any one of claims 1 to 13, wherein the communication control unit is configured to allocate a band to the communication based on the number of carriers determined by the determination unit. Further comprising storage means configured to store noise information of each band in the communication line;
The detection means is configured to acquire a priority of communication by the other power line communication device based on a signal received from the other power line communication device,
The communication control unit is configured to allocate communication by the other power line communication device to a band with less noise among a plurality of bands of the communication line according to the acquired priority. The power line communication device according to any one of claims 1 to 13.   When the power line communication device is communicating with a plurality of other power line communication devices, the communication control unit assigns communication by each of the other power line communication devices to each band in descending order of priority, and The power line communication apparatus according to claim 15, wherein the power line communication apparatus is configured to perform in order of increasing noise in the band.   The power line communication device according to claim 15, wherein the communication control unit is configured to assign communication with high priority to a band in which a noise level is lower than a preset reference.   18. The update apparatus according to claim 15, further comprising an update unit configured to update noise information stored in the storage unit before allocating communication to a plurality of bands of the communication line. A power line communication apparatus according to claim 1.

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