JP2011114424A - Communication system, and communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the reliability of the communication of a communication system utilizing cable communication and radio communication. <P>SOLUTION: The communication system includes a first communication device and a plurality of second communication devices. The second communication device is capable of transmitting and receiving packets by a plurality of communication unit including both of a cable system and a radio system. The second communication device relays a first packet transmitted from the first communication device, and also relays a second packet for responding to the first packet. When relaying the second packet, the second communication device relays the second packet so as to trace back a route that the first packet has taken. The second communication device receives the first packet having the same identification information by both of the cable system and the radio system, and when the signal quality of the first packet received by the cable system is at or below a preset threshold, relays the first packet received by the radio system without relaying the first packet received by the cable system. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication system and a communication apparatus constituting the communication system.

  Conventionally, wired or wireless communication methods have been used, and recently, power line communication (Power Line Communication: PLC) using a power line has been put into practical use as one of wired communication. Further, a communication system using both wired communication and wireless communication is disclosed in Patent Documents 1 and 2, for example.

  The communication system described in Patent Document 1 performs communication of a slave operation using a wireless host that performs a master operation, a wired / wireless bridge device that communicates with the wireless host via a wireless link, and a wired link with the wired / wireless bridge device. A plurality of devices. In this communication system, a wired / wireless bridge device performs transfer control with a plurality of devices according to a communication band of a wireless link.

  The communication system described in Patent Document 2 includes end devices such as personal computers and mobile phones, and link devices such as routers and HUBs. The end device and the link device transmit / receive data to / from each device via a plurality of wired or wireless links on the network by a communication interface unit included in each end device and link device.

  End devices and link devices are a link database that stores link information, a device database that stores device information, and a route table that stores information about communication paths between devices (created based on the link database and device database) ). And, the end device and the link device include a link search process for searching for a device that can be linked to the own device, an information exchange process for exchanging link information and device information with the linked device, and construction of a communication path between the devices, The route management process for switching, managing, etc. is repeatedly executed.

  Each device monitors the communication status of the communication path established with the communication device of the communication partner by the above-described various databases and various processes, and communicates with the communication partner when the communication status changes. The communication path to be used is switched to another communication path that can be established with the communication apparatus of the communication partner.

JP 2006-217476 A JP 2007-221564 A

  In the communication system of Patent Document 1, the wireless host and the wired / wireless bridge device are connected by wireless communication, and the wired / wireless bridge device and the device are connected by wired communication. That is, the communication system has a fixed transmission / reception path for data and the like.

  On the other hand, in the communication system of Patent Document 2, when the communication status of the communication path established with the communication partner communication apparatus changes, other communication that can be established with the communication partner communication apparatus. Switch to the route. For this reason, it is considered that the communication system can be operated more flexibly.

  However, in the communication system of Patent Document 2, each device has a large number of databases. For the above-described path switching, the database is updated to correspond to the change in the configuration of the communication system and the change in the communication state. Need to keep. For this reason, each device and system as a whole is required to have high performance, which is likely to increase complexity and cost.

  An object of the present invention is to provide an inexpensive communication system that can flexibly construct a communication network and that has a simple configuration for a communication system that uses wired communication and wireless communication.

  It is another object of the present invention to improve communication reliability for such a communication system.

  Moreover, an object of this invention is to provide the communication apparatus which can implement | achieve such a communication system.

  The communication system according to claim 1 of the present invention is configured to be able to transmit and receive packets by the first communication device and a plurality of communication means including both a wired method and a wireless method, and has a function of relaying received packets. Each of the plurality of second communication devices is relayed by the second communication device when relaying the first packet transmitted from the first communication device. Information to the effect and information on the type of communication means used for relay among the plurality of communication means are recorded in the first packet as forward route information, and a second packet for responding to the first packet Is generated, the outbound route information is copied and recorded in the second packet as inbound route information, and when the second packet is relayed, the first route is based on the inbound route information. The second packet is relayed so as to follow the route followed by the packet in reverse order, and each of the plurality of second communication devices transmits the first packet having the same identification information by both the wired method and the wireless method. When the signal quality of the first packet received and received by the wired method is less than or equal to a preset threshold, the first packet received by the wired method is not relayed but received by the wireless method Relay the first packet.

  The communication system according to claim 2 of the present invention is configured to be able to transmit and receive packets by the first communication device and a plurality of communication means including both a wired method and a wireless method, and has a function of relaying received packets. Each of the plurality of second communication devices is relayed by the second communication device when relaying the first packet transmitted from the first communication device. Information to the effect and information on the type of communication means used for relay among the plurality of communication means are recorded in the first packet as forward route information, and a second packet for responding to the first packet Is generated, the outbound route information is copied and recorded in the second packet as inbound route information, and when the second packet is relayed, the first route is based on the inbound route information. The second packet is relayed so as to follow the route followed by the packet in reverse order, and each of the plurality of second communication devices respectively receives a plurality of first packets having the same identification information by the plurality of communication means. In this case, the communication quality of the communication path followed by the plurality of first packets is evaluated according to a predetermined evaluation method, and the first packet that has arrived following the communication path evaluated to have the highest communication quality is The first packet that has been relayed and arrived along the remaining communication path is not relayed.

  A communication system according to a third aspect of the present invention is the communication system according to the second aspect, wherein the evaluation method related to the communication quality is such that the reception quality of the first packet is lower than a preset threshold. If it is higher, an evaluation method for determining that the communication path of the first packet has usable communication quality, and the smaller the number of relay stages that the first packet has passed, the higher the communication quality is evaluated. Including evaluation methods.

  A communication system according to a fourth aspect of the present invention is the communication system according to any one of the first to third aspects, wherein the plurality of communication means include a power line communication means and at least one type of wireless communication. Communication means.

  The communication device according to claim 5 of the present invention is a communication device as a slave station that constitutes a communication system together with a parent station, and can transmit and receive packets by a plurality of communication means including both a wired method and a wireless method. When the first packet transmitted from the master station is relayed, information indicating that the relay has been relayed by the communication device and the communication means used for relaying among the plurality of communication means When the second packet for responding to the first packet is generated by recording information on the type in the first packet as the outbound route information, the outbound route information is copied as the inbound route information. When recording the two packets and relaying the second packet, the second packet is relayed so as to follow the route followed by the first packet based on the return route information in reverse order, When the first packet having the same identification information is received by both the wired method and the wireless method, and the signal quality of the first packet received by the wired method is below a preset threshold, The first packet received by the wired method is not relayed, but the first packet received by the wireless method is relayed.

  A communication apparatus according to claim 6 of the present invention is a communication apparatus as a slave station that constitutes a communication system together with a master station, and can transmit and receive packets by a plurality of communication means including both a wired system and a wireless system When the first packet transmitted from the master station is relayed, information indicating that the relay has been relayed by the communication device and the communication means used for relaying among the plurality of communication means When the second packet for responding to the first packet is generated by recording information on the type in the first packet as the outbound route information, the outbound route information is copied as the inbound route information. When recording the two packets and relaying the second packet, the second packet is relayed so as to follow the route followed by the first packet based on the return route information in reverse order, When the plurality of first packets having the same identification information are respectively received by the plurality of communication means, the communication quality of the communication path followed by the plurality of first packets is evaluated according to a predetermined evaluation method, and the communication quality The first packet arriving along the communication path evaluated as the highest is relayed, and the first packet arriving along the remaining communication path is not relayed.

  According to the communication system according to the first and second aspects of the present invention, packets transmitted from the first communication device are relayed one after another by the plurality of second communication devices and distributed to each second communication device. The For this reason, a network is dynamically and flexibly constructed according to the overall configuration and communication state of the communication system at the time of packet distribution. In addition, since each second communication device does not need to grasp the network configuration on the communication system or changes thereof, for example, by a database, the second communication device can be configured simply, thereby reducing the cost of communication. A system can be provided.

  According to the communication system of the first aspect of the present invention, when the signal quality of the first packet received by the wired method is equal to or lower than a preset threshold value, the first packet received by the wired method is relayed. Instead, the first packet received by the wireless method is relayed. Since the second packet for responding to the first packet follows the path (outward path) followed by the first packet in the reverse order, the second packet is transmitted while avoiding the above-mentioned wired path whose reception signal quality is not good. be able to. For this reason, the lost second packet can be prevented. Therefore, a highly reliable communication system can be provided.

  Further, according to the communication system according to claim 2 of the present invention, the first packet that arrives along the communication path evaluated as having the highest communication quality is relayed and arrives along the remaining communication path The first packet is not relayed. Since the second packet for responding to the first packet follows the path (outward path) followed by the first packet in the reverse order, the second packet can be transmitted through the communication path evaluated to have the highest communication quality. For this reason, the lost second packet can be prevented. Therefore, a highly reliable communication system can be provided.

  According to the communication system of the third aspect of the present invention, the communication quality can be evaluated in detail from a plurality of viewpoints of reception quality and number of relay stages. As a result, the lost second packet can be prevented more reliably, and the reliability of the communication system can be further improved.

  According to the communication system of the fourth aspect of the present invention, the power line communication means is included. In general, power line communication is less stable in communication quality than wireless communication. Therefore, for a communication system employing such power line communication, it is possible to prevent lost second packets and improve reliability.

  According to the communication apparatus according to claim 5 of the present invention, a communication system having the same effect as the communication system according to claim 1 of the present invention can be configured.

  According to the communication device described in claim 6 of the present invention, it is possible to configure a communication system having the same effect as the communication system described in claim 2 of the present invention.

It is a schematic diagram explaining the structure of the communication system which concerns on embodiment, and an outward relay process. It is a block diagram explaining the structure of the 1st communication apparatus which concerns on embodiment. It is a block diagram explaining the structure of the 2nd communication apparatus which concerns on embodiment. It is a schematic diagram explaining the encryption process which concerns on embodiment. It is a schematic diagram explaining the request packet which concerns on embodiment. It is a schematic diagram explaining the response packet which concerns on embodiment. It is a flowchart explaining the outward relay process which concerns on embodiment. It is a flowchart explaining the outward relay process which concerns on embodiment. It is a flowchart explaining the inbound trip relay process which concerns on embodiment. It is a schematic diagram explaining the return trip relay process which concerns on embodiment. It is a sequence diagram which arranges and shows the relay processing of the outgoing way and the return way concerning an embodiment. It is a flowchart explaining the outward relay process which concerns on embodiment. It is a flowchart explaining the outward relay process which concerns on embodiment. It is a flowchart explaining the outward relay process which concerns on embodiment. It is a sequence diagram explaining the electric energy acquisition process which concerns on embodiment. It is a schematic diagram explaining the electric energy acquisition process which concerns on embodiment. It is a flowchart explaining the sensor state acquisition process which concerns on embodiment. It is a schematic diagram explaining the sensor state acquisition process which concerns on embodiment.

  FIG. 1 shows a schematic diagram of a communication system 1 according to an embodiment of the present invention. As shown in FIG. 1, the communication system 1 includes a first communication device 10 and a plurality of second communication devices 20. The first communication device 10 functions as a central / core device in the communication system 1, a so-called master station device. On the other hand, the second communication device 20 functions as a slave station device or as a relay station device that relays information transmitted from the first communication device 10 to another second communication device 20.

  Here, six second communication devices 20 are illustrated, and reference numerals 21 to 26 are used to distinguish them. Note that the number of second communication devices 20 is not limited to six.

  Although a specific configuration example will be described later, the first communication device 10 is configured to be capable of power line communication, while the second communication device 20 is configured to be capable of both power line communication and wireless communication. . Thus, in the communication system 1, a communication network that transmits and receives information between the first communication device 10 and the second communication device 20 using the power line 30 is constructed, and between the second communication devices 20. A communication network that transmits and receives information using the power line 30 and radio is constructed.

  In the configuration illustrated in FIG. 1, the first communication device 10 and the second communication devices 21 to 23 are connected to the power line 31, the second communication devices 24 and 25 are connected to the power line 32, and the second communication device 26 is the power line 33. It is connected to the. These three power lines 31 to 33 schematically represent a case where the power line 30 is a single-phase three-wire wiring used in a home electrical equipment structure such as a general house. That is, in the three-wire wiring, the power line 31 is configured by the first wiring and the second wiring arbitrarily selected from the three wirings, and the power line 32 is configured by the second wiring and the third wiring. Then, the power line 33 is configured by the third wiring and the first wiring. Note that the power line 30 to which the communication system 1 can be applied is not limited to a single-phase three-wire system.

  Here, the block diagram of FIG. 2 shows a configuration example of the first communication device 10. In FIG. 2, the power line 30 and the like are also shown for explanation. In the configuration illustrated in FIG. 2, the first communication device 10 includes a wiring 10a, a power line communication unit 10b, a processing unit 10c, a storage unit 10d, a network communication unit 10e, a connection terminal 10f, and an input unit 10g. Is included.

  The wiring 10a is for electrically connecting the power line 30 and the first communication device 10, and is connected to the power line communication unit 10b. By connecting the wiring 10 a to the power line 30 (power line 31 in the example of FIG. 1), an electrical connection is established between the power line 30 and the first communication device 10. The wiring 10a and the power line 30 can be connected by, for example, an insertion connector (an insertion plug and a plug receptacle).

  The power line communication unit 10 b includes an interface (I / F) for performing power line communication via the power line 30. The power line communication unit 10b can also be configured to include an interface for supplying power from the power line 30 to each unit in the first communication device 10. For example, various known interface circuits can be applied to the power line communication interface and the power supply interface.

  The processing unit 10c performs various processes related to the operation of the first communication device 10 and controls the power line communication unit 10b and the like as necessary. The processing unit 10c is connected to the power line communication unit 10b, the storage unit 10d, the network communication unit 10e, and the input unit 10g. 2 illustrates the case where the power line communication unit 10b and the like are connected in a so-called star-type connection form with the processing unit 10c as the center. For example, a bus-type or ring-type connection form is applied. May be.

  Here, a case where various processes by the processing unit 10c are realized by software is illustrated. In this case, the processing unit 10c includes, for example, a microcomputer, and the microcomputer executes each processing step (in other words, a procedure) described in the program. Thereby, the microcomputer functions as various means corresponding to the processing step, or various functions corresponding to the processing step are realized by the microcomputer. It should be noted that various means or various functions realized by the processing unit 10c may be realized by hardware.

  The storage unit 10d is composed of one or more of various storage devices such as a ROM (Read Only Memory), a RAM (Random Access Memory), a rewritable nonvolatile memory (EPROM (Erasable Programmable ROM), etc.), and a hard disk device, for example. Has been. The storage unit 10d stores a program executed by the processing unit 10c, and provides a work area for executing the program.

  The storage unit 10d can also store various information and data. Information stored in the storage unit 10d includes information for uniquely identifying the first communication device 10, for example. Such device identification information is used as a packet transmission destination, for example, as will be described later. As the device identification information, for example, a MAC address, an IP address, or the like can be used. For example, a number, a code, or the like set in advance in the communication system 1 can be used. Here, for easy understanding, the identification information is also referred to as a device number, and the device number of the first communication device 10 is expressed as “10”.

  The network communication unit 10 e includes an interface for communicating with the network 40 provided outside the first communication device 10, for example, an Ethernet (registered trademark) standard interface. The network communication unit 10e is connected to the connection terminal unit 10f, and is connected to the network 40 via the terminal unit 10f. The network 40 is, for example, the so-called Internet, LAN, etc., and is separate from the network constructed by the communication system 1. In FIG. 2, the network 40 also includes a center 45 that communicates with the first communication device 10.

  The input unit 10g is an interface for a user to input an instruction or the like to the first communication device 10. The input unit 10g can be configured to include input devices such as buttons, switches, touch panels, keyboards, and mice. The input unit 10g may include a contact type, non-contact type, or optical information reader (for example, a card reader or a code reader), or may include a voice input device or the like.

  The block diagram of FIG. 3 shows a configuration example of the second communication device 20. In FIG. 3, the power line 30 and the like are also shown for explanation. In the configuration illustrated in FIG. 3, the second communication device 20 includes a wiring 20a, a power line communication unit 20b, a processing unit 20c, a storage unit 20d, a wireless communication unit 20e, a connection terminal 20f, and a power measurement unit 20g. And a device communication unit 20h and a notification unit 20i.

  The wiring 20a is for electrically connecting the power line 30 and the second communication device 20, and is connected to the power line communication unit 20b. Electrical connection is established between the power line 30 and the second communication device 20 by connecting the wiring 20a to the power line 30 (any of the power lines 31 to 33 in the example of FIG. 1). The wiring 20a and the power line 30 can be connected by, for example, an insertion connector (an insertion plug and a plug receptacle).

  The wiring 20a electrically connects the power line 30 and the connection terminal 20f. For this reason, when connecting the device 51 such as an electric device to the connection terminal 20f, it is possible to supply power to the device 51 provided outside the device 20 via the second communication device 20. . The connection terminal 20f can be configured by, for example, a plug receptacle of a plug connector.

  The power line communication unit 20 b includes an interface for performing power line communication via the power line 30. The power line communication unit 20b can also be configured to include an interface for supplying power from the power line 30 to each unit in the second communication device 20. Each interface can be configured in the same manner as that of the power line communication unit 10b (see FIG. 2), for example.

  The processing unit 20c performs various processes related to the operation of the second communication device 20, and controls the power line communication unit 20b and the like as necessary. The processing unit 20c is connected to the power line communication unit 20b, the storage unit 20d, the wireless communication unit 20e, the power measurement unit 20g, the device communication unit 20h, and the notification unit 20i. In addition, the connection between each part is not restricted to the form illustrated in FIG.

  Here, a case where various processes by the processing unit 20c are realized by software is illustrated. In this case, the processing unit 20c can be configured similarly to the processing unit 10c (see FIG. 2). It should be noted that some or all of the various means or functions realized by the processing unit 20c can be realized by hardware.

  The storage unit 20d can be configured in the same manner as the storage unit 10d (see FIG. 2), stores a program executed by the processing unit 20c, and provides a work area for executing the program.

  The storage unit 20d stores identification information similar to the device identification information of the first communication device 10, and the second communication device 20 is uniquely identified by the identification information. Here, in order to make the explanation easy to understand, the device identification information (device numbers) of the six second communication devices 21 to 26 illustrated in FIG. 1 is expressed as “21” to “26”, Moreover, when not distinguishing these 2nd communication apparatuses 21-26, it will describe with "20".

  The wireless communication unit 20e includes an interface for performing wireless communication with another second communication device 20, for example, an interface conforming to a standard such as ZigBee (registered trademark) or Bluetooth (registered trademark).

  Here, the range in which wireless communication by the wireless communication unit 20e is possible (in other words, the reach of wireless radio waves) may be affected by, for example, the installation location of the second communication device 20 or the like. With regard to this point, FIG. 1 schematically illustrates a wireless communication possible range by the wireless communication unit 20e with a broken-line circle. For example, the wireless communicable range of the second communication devices 22, 23, 25 is illustrated narrower than the same range of the second communication devices 21, 24, 26. In addition, the wireless communicable range of the second communication devices 21, 24, 26 is illustrated as a substantially circular range centering on the devices 21, 24, 26. On the other hand, the wireless communicable range of the second communication devices 22, 23, 25 is illustrated narrowly on the lower side in the figure.

  In the illustration of FIG. 1, the wireless communication possible range of the second communication device 21 overlaps the same range of the second communication devices 22 and 24, and the wireless communication possible range of the second communication device 26 is the second communication device. It overlaps with the same range of the device 24. For this reason, the 2nd communication apparatuses 20 with which the radio | wireless communicable range has overlapped can directly perform radio | wireless communication. In addition, by using the second communication device 20 having overlapping wireless communication ranges as a relay station, it is also possible to perform wireless communication indirectly with the second communication device 20 ahead.

  On the other hand, in the illustration of FIG. 1, the second communication devices 23 and 25 do not overlap with the other second communication devices 20, so that wireless communication is not performed with the other communication devices 20. .

  Returning to FIG. 3, the power measuring unit 20g is installed with respect to the wiring 20a, and includes a meter for measuring the power (power amount) flowing through the wiring 20a. As the instrument, for example, various known methods can be applied. According to the power measurement unit 20g, it is possible to measure the power consumption of the device 51 connected to the connection terminal 20f.

  The device communication unit 20h includes an interface for performing communication with the device 52 such as a device having a wireless LAN function. Here, the case where the device communication unit 20h performs wireless communication is illustrated, but it may be configured to perform wired communication. As the wireless communication interface, for example, an interface conforming to a standard such as ZigBee (registered trademark) or Bluetooth (registered trademark) can be applied. For this reason, when the device 52 is provided in a range where wireless communication with the device communication unit 20h is possible, the second communication device 20 and the device 52 are connected by wireless communication by the device communication unit 20h.

  Note that the device 52 may be wirelessly connected to the plurality of second communication devices 20. In some cases, the device 52 is connected to the connection terminal 20f to receive power.

  The device communication unit 20h and the wireless communication unit 20e are configured to be different from each other in order to prevent interference, or configured to perform wireless communication using different channels even with the same standard.

  FIG. 3 illustrates a case where two types of devices 51 and 52 having different connection forms with the second communication device 20 are connected to the second communication device 20. On the other hand, only one of the devices 51 and 52 may be connected to the second communication device 20, or none of the devices 51 and 52 may be connected to the second communication device 20. .

  The notification unit 20 i is an interface for notifying a user who is outside the device 20 of the operation state of the second communication device 20. The notification unit 20i can be configured to include a device that visually notifies, such as one or a plurality of light emitting elements (LEDs, etc.), a liquid crystal display, and the like. Further, in addition to or instead of a device that visually notifies, the notification unit 20i can be configured to include a device that performs an audible notification using an alarm sound or voice.

  Note that not all of the second communication devices 20 used in the communication system 1 need to have the same configuration. For example, the second communication device 20 that does not have one or more of the power measurement unit 20g, the device communication unit 20h, and the notification unit 20i can be used. Moreover, you may use the 2nd communication apparatus 20 which has an additional element with respect to the structure of the said illustration.

  The communication devices 10 and 20 transmit information to be transmitted in packets. At this time, the communication devices 10 and 20 generate a packet corresponding to the transmission information, and encrypt the packet using, for example, an encryption key (see FIG. 4). The communication devices 10 and 20 decrypt the received packet using, for example, an encryption key. For this reason, the communication apparatuses 10 and 20 have the same encryption key. The encryption key is set uniquely, that is, uniquely for the first communication device 10. For this reason, even if the inflow / outflow of a packet occurs between another communication system 1 in which the first communication device 10 is different, the packet is not used. For this reason, good security can be obtained.

  For example, there is AES as a method using an encryption key. Various encryption / decryption methods can be used. Packet generation and encryption / decryption processing are performed by the processing units 10c and 20c. The processing units 10c and 20c appropriately adjust the number of bits of a packet to be encrypted by, for example, zero padding in the encryption process.

  5 and 6 illustrate packets used in the communication system 1. FIG. 5 schematically illustrates an example of the request packet 100 used when the first communication device 10 makes a predetermined request to the second communication device 20. FIG. 6 schematically illustrates an example of a response packet 200 used when the second communication device 20 responds to the request.

  The request packet illustrated in FIG. 5 includes information 102, 104, 106, 110. 5 does not limit the description position and data length of the information 102, 104, 106, 110 in the request packet 100.

  The information 102 is information for designating the second communication device 20 as a transmission destination, and for example, identification information for distinguishing each second communication device 20 is described. Here, it is assumed that the request packet 100 is transmitted to all the second communication devices 20, and information indicating that all the second communication devices 20 are transmission destinations is described in the transmission destination device information 102.

  The information 104 is information for identifying the request packet 100. Here, the sequence number of the request packet 100 is exemplified. In this case, the sequence number 104 corresponds to a number starting from 0 (zero) and incremented each time a request packet is generated.

  The information 106 is information related to processing requested to the second communication device 20. For example, a command is set in advance corresponding to the requested process, and the request command is given as information 106.

  The information 110 is information regarding a route that the request packet 100 follows in the communication system 1. Specifically, the communication device 10, 21-26 is connected to the communication device 10, 21-26 when the request packet 100 is transmitted (including retransmission performed by the second communication device 20 as a relay station). Is recorded by adding to the route information 110 as a unit (route unit).

  For easy understanding, the distinction between the communication devices 10 and 21 to 26 is represented by the above device numbers “10”, “21” to “26”, and transmission by power line communication is represented as “P”. The transmission by wireless communication is expressed as “R”, and the above two distinct items are connected by “:”. For example, a path unit indicating transmission using power line communication by the first communication device 10 is represented as “10: P”, and for example, a path unit indicating transmission using wireless communication by the second communication device 21 is “21: R”. (See FIG. 1).

  In addition, by adding the path unit to the end by separating it with “/”, the additional writing of the path unit is described. For example, in the example of FIG. 1, when the request packet 100 is transmitted from the first communication device 10 by power line communication and then retransmitted (relayed) by wireless communication from the second communication device 21, the contents of the route information 110 Is written as “10: P / 21: R”. When the request packet 100 is further relayed by power line communication by the second communication device 24, the content of the route information 110 is expressed as “10: P / 21: R / 24: P”.

  In FIG. 1, in order to make the explanation easier to understand, a quadrangular shape surrounding a notation such as “10: P” is devised. That is, a solid rectangle represents transmission / reception by power line communication, and a broken line rectangle represents transmission / reception by wireless communication. In addition, a thick solid line and a broken-line rectangle represent transmission of a packet, and a thin solid line and a broken-line rectangle represent reception of a packet.

  The response packet 200 illustrated in FIG. 6 includes information 202, 204, 206, 208 and 210. FIG. 6 does not show the description position and data length of the information 202, 204, 206, 208, 210 in the response packet 200.

  In the information 202, transmission destination apparatus information is described in the same manner as the information 102 (see FIG. 5). However, in the response packet 200, the second communication device 20 to be received next is specified, and identification information (device number) of the communication device 20 is described in the transmission destination device information 202.

  As will be described later, the response packet 200 is transmitted back to the first communication device 10 along the transmission path of the corresponding request packet 100, that is, the forward path. At this time, the second communication device 20 that is the next transmission destination in the route that the response packet 200 follows, that is, the return route, is specified by the information 204. The information 204 is realized by, for example, a pointer that sequentially points the route units described in the route information 210 below in the order of the routes.

  The information 206 is information related to the request command similar to the information 106 (see FIG. 5), and the same information as the request command 106 of the request packet 100 is described.

  Information 208 is information related to the response content, and will be exemplified later.

  Information 210 is information related to the return path followed by the response packet 200. The information 210 is generated based on the path information 110 of the corresponding request packet 100 by the second communication device 20 that is the origin of transmission of the response packet 200. For example, the path information 210 is generated by copying the path information 110 of the request packet 100 as it is, or by copying the path units described in the path information 110 in reverse order. Both of the path information 110 and 210 include the same contents by any copy method.

  The route information 210 is not added by the second communication device 20 on the return route. The return route information 210 also uses the same notation method as the forward route information 110.

  Here, for example, the value “0” of the return path pointer 204 is associated with the head path unit in the path information 210, and the values “1”, “2”,. When sequentially associating with the second, third,... Path units, the path units in the path information 210 can be traced sequentially by incrementing or decrementing the value of the return path pointer 204.

  The packets 100 and 200 may be configured to further include other information (such as an error detection code). For example, when an error detection code is included, the processing units 10c and 20c can take measures such as not using the packets 100 and 200 in which a data error has occurred.

  FIG. 7 illustrates a flowchart of an operation of the second communication device 20 that has received the request packet 100, more specifically, a process (outward relay process) S2 when the request packet 100 is relayed.

  First, when the second communication device 20 receives the request packet 100 (step S20), the packet 100 is decoded by the processing unit 20c (step S22).

  The transmission source immediately before the received request packet 100 may be the first communication device 10 or the other second communication device 20. In addition, the request packet 100 may be received by the power line communication unit 20b or may be received by the wireless communication unit 20e. For example, in the example of FIG. 1, the second communication device 22 can receive the request packet 100 directly from the first communication device 10 through power line communication (that is, without relaying by another second communication device 20). In addition, it is also possible to receive the request packet 100 by wireless communication via relay by the second communication device 21.

  Then, the processing unit 20c determines whether it is necessary to relay the request packet 100, in other words, transfer (step S24). An example of the relay necessity determination step S24 is shown in the flowchart of FIG.

  In the relay necessity determination step S24 illustrated in FIG. 8, the processing unit 20c first determines whether or not the request packet 100 to be relayed has already been relayed by the second communication device 20 (step S24). S24a). If it is determined that the relay has already been performed, the processing unit 20c ends the forward relay processing S2 (see FIG. 7) without performing the relay processing of the received request packet 100. On the other hand, when it determines with having not been relayed, the process part 20c performs the following step S24b.

  The determination step S24a can be executed by using, for example, the sequence number 104 (see FIG. 5) included in the request packet 100. Specifically, the processing unit 20c records the sequence number 104 of the request packet 100 that has been relayed in the storage unit 20d, and the request packet 100 to be relayed has already been relayed by collation with the record. It is possible to determine whether or not there is.

  Thus, according to the determination step S24a, the second communication device 20 receives the request packet 100 having the same sequence number 104, that is, the packet 100 having the same transmission content (here, the request content is the same) a plurality of times. The request packet 100 received after the second time is not relayed. For this reason, it is possible to prevent packets 100 having the same transmission content from being continuously relayed and transferred on the communication system 1 indefinitely. Thereby, the transmission load of the communication system 1 can be reduced.

  In step S24b, the processing unit 20c determines whether the number of relays (the number of relay stages) of the received request packet 100 so far is smaller than a preset maximum number of relays. In other words, it is determined whether or not the maximum number of relays is exceeded by performing the current relay. If it is determined that the number of relays so far is less than the maximum number of relays, the processing unit 20c ends the relay necessity determination step S24 and executes the next step S26. On the other hand, if it is determined that the number of relays so far has reached the maximum number of relays, the processing unit 20c ends the forward relay process S2 (see FIG. 7) without performing the relay process of the received request packet 100. .

  The maximum number of relays described above can be used in step S24b, for example, by describing in advance in the program, or by storing in advance in the storage unit 20d, for example.

  According to the determination process in step S24b, it is possible to prevent packets 100 having the same transmission contents (here, the same request contents) from being continuously relayed and transferred on the communication system 1. Thereby, the transmission load of the communication system 1 can be reduced.

  The execution order of steps S24a and S24b may be the reverse of the above.

  After the end of step S24, the processing unit 20c determines whether or not the request packet 100 has been received by wireless communication (step S26, see FIG. 7). As a result of such classification, in the case of reception by wireless communication, the processing unit 20c performs both power line communication processing S28 and wireless communication processing S30. On the other hand, if the reception is not wireless communication, that is, reception by power line communication, the processing unit 20c performs only the wireless communication processing S30.

  In the power line communication processing S28 illustrated in FIG. 7, the processing unit 20c determines the device number of the second communication device 20 that performs the current relay and the communication method (power line communication in this case) used for the current relay in the request packet 100. It adds to the route information 110 (step S28a). Then, the processing unit 20c encrypts the request packet 100 (step S28b), controls the power line communication unit 20b (see FIG. 3), and transmits the request packet 100 (step S28c).

  In the wireless communication processing S30 illustrated in FIG. 7, the processing unit 20c determines the device number of the second communication device 20 that performs the current relay and the communication method (in this case, wireless communication) used for the current relay. It adds to the route information 110 (step S30a). Then, the processing unit 20c encrypts the request packet 100 (step S30b), controls the wireless communication unit 20e (see FIG. 3), and transmits the request packet 100 (step S30c).

  Here, in the range illustrated in FIG. 1, it is assumed that the request packet 100 is transmitted as follows by the forward relay processing S2. Here, it is assumed that power line communication is not performed between the different-phase power lines 31 to 33.

  The request packet 100 transmitted from the first communication device 10 is received by the second communication devices 21 to 23 through the power line 31, and is retransmitted by wireless communication of the second communication devices 21 to 23 (step S26, S30).

  The request packet 100 retransmitted from the second communication device 21 is received by the second communication devices 22 and 24 having overlapping wireless communication ranges. However, since the second communication device 22 has already relayed the received packet 100 as described above, the packet 100 relayed by the second communication device 21 is not retransmitted (see step S24a). On the other hand, the second communication device 24 retransmits the received packet 100 received by wireless communication by power line communication and wireless communication (see steps S26, S28, and S30).

  Further, the request packet 100 retransmitted from the second communication device 22 is received by the second communication device 21 with which the wireless communication coverage is overlapped, but the second communication device 21 has already relayed as described above. Therefore, the packet 100 relayed by the second communication device 22 is not retransmitted (see step S24a).

  Further, the request packet 100 retransmitted from the second communication device 23 is not transmitted to the other second communication devices 20 because there is no second communication device 20 having overlapping wireless communication ranges.

  The request packet 100 retransmitted by the power line communication from the second communication device 24 as described above is received by the second communication device 25 and retransmitted using wireless communication (see steps S26 and S30). However, since there is no second communication device 20 that overlaps the wireless communication range with the second communication device 25, the request packet 100 is not transmitted from the second communication device 25 first.

  The request packet 100 retransmitted from the second communication device 24 by wireless communication is received by the second communication device 26 and retransmitted from the second communication device 26 by power line communication and wireless communication (step S26). , S28, S30).

  Next, FIG. 9 illustrates a flowchart of an operation of the second communication device 20 that has received the response packet 200, more specifically, a process (return relay process) S6 when the response packet 200 is relayed.

  Here, the second communication device 20 that is the transmission start point of the response packet 200 uses the route information 110 (see FIG. 5) of the request packet 100 in the step of generating the response packet 200 (see step S4 described later). In this example, the path information 210 is copied in the reverse order and the path information 210 is initialized, and the return path pointer 204 (see FIG. 6) is initialized to “0”.

  First, when the second communication device 20 receives a response packet 200 from another second communication device 20 (step S50), the packet 200 is decoded by the processing unit 20c (step S52). Note that steps S50 and S52 are not performed in the second communication device 20 that is the transmission start point of the response packet 200.

  Then, the processing unit 20c increments the return path pointer 204 (step S54), and sets the transmission destination device information 202 (step S56). Specifically, the processing unit 20c analyzes the path unit indicated by the incremented return path pointer 204, and sets the apparatus number of the second communication apparatus 20 described in the path unit in the transmission destination apparatus information 202. Then, the processing unit 20c encrypts the response packet 200 (step S58).

  Next, the processing unit 20c sorts the communication method used in the forward path by the second communication device 20 designated as the next transmission destination (step S60). Specifically, the path unit indicated by the return path pointer 204 incremented in step S54 is analyzed, and the communication methods described in the path unit are classified.

  When it is determined in step S60 that the forward path is wireless communication, the processing unit 20c transmits the response packet 200 by wireless communication (step S62). On the other hand, when it is determined that the forward path is power line communication, the processing unit 20c transmits the response packet 200 by power line communication (step S64).

  Here, a transmission example of the response packet 200 is illustrated in FIG. FIG. 10 illustrates a case where the response packet 200 is transmitted from the second communication device 25 to the first communication device 10 based on the transmission example of the request packet 100 (see FIG. 1). A part of 1 is extracted and shown.

  First, according to the transmission example of FIG. 1, information “10: P / 21: R / 24: P” is recorded in the route information 110 of the request packet 100 received by the second communication device 25. For this reason, the second communication device 25 records the information “24: P / 21: R / 10: P” obtained by inverting the arrangement of the route units of the route information 110 in the route information 210 of the response packet 200 ( (See FIG. 10). The second communication device 52 initializes the return path pointer 204 to “0” (see step S54). As a result, the return path pointer 204 points to the head path unit “24: P”. In FIG. 10, the return path pointer 204 is schematically shown by an arrow for easy understanding.

  Based on the path unit “24: P” pointed to by the return path pointer 204, the second communication apparatus 25 sets the second communication apparatus 24 as a transmission destination (see step S56), and transmits the response packet 200 by power line communication (step S56). (See S60 and S64).

  The second communication device 24 increments the return path pointer 204 of the received response packet 200 (see step S54). Then, based on the path unit “21: R” pointed to by the return path pointer 204, the second communication device 24 transmits the response packet 200 to the second communication device 21 by wireless communication (see steps S54, S56, S60, and S62). .

  The second communication device 21 increments the return path pointer 204 of the received response packet 200 (see step S54). Then, based on the path unit “10: P” pointed to by the return path pointer 204, the second communication device 21 transmits the response packet 200 to the first communication device 10 by power line communication (see steps S54, S58, S60, and S64). .

  The transmission of the response packet 200 illustrated in FIG. 10 is illustrated together with the transmission of the corresponding request packet 100 in the sequence diagram of FIG. In FIG. 11, step S <b> 0 is a transmission process of the request packet 100 by the first communication device 10, and includes an initial generation process of the packet 100. Step S4 is the initial generation and transmission process of the response packet 200 by the second communication device 10.

  As described above, the second communication device 20 transmits the packet 100 transmitted from the first communication device 10 directly from the first communication device 10 or via the other second communication device 20 by power line communication. When received, the received packet 100 is relayed by wireless communication. On the other hand, when the packet 100 transmitted from the first communication device 10 is received by wireless communication via the other second communication device 20, the packet 100 is relayed by both wireless communication and power line communication.

  For this reason, the packets transmitted from the first communication device 10 are relayed one after another by the plurality of second communication devices 20 and delivered to each second communication device 20. For this reason, a network is dynamically and flexibly constructed according to the overall configuration and communication state of the communication system 1 at the time of packet distribution. In addition, since each second communication device 20 does not need to grasp the network configuration on the communication system 1 or changes thereof, for example, by a database, the second communication device 20 can have a simple configuration. The communication system 1 can be made inexpensive.

  Further, as described above, a route (outward route) followed by the request packet 100 is recorded, and the response packet 200 travels on the communication system based on the record. For this reason, the response packet 00 can be efficiently transmitted to the first communication device 10.

  In the above example, when the second communication device 20 receives the request packet 100 having the same sequence number 104 a plurality of times, the second communication device 20 relays the request packet 100 received first and receives the request packet received second and subsequent times. 100 is not relayed (see step S24 in FIGS. 7 and 8). That is, the request packet 100 that arrives first is adopted, and the request packet 100 that arrives second or later is discarded.

  For example, referring to FIG. 1, the second communication device 22 can receive the request packet 100 transmitted from the second communication device 21 by both power line communication and wireless communication. And the case where the request packet 100 by power line communication arrived first and was employ | adopted was illustrated above.

  Regarding this point, even if the power line communication and the wireless communication can be received, the request packet 100 by the power line communication comes first according to the specification in which the power line communication has a higher communication speed.

  Moreover, since power line communication uses a power line, a device connected to the power line may deteriorate the communication quality of the power line communication.

  Further, as described above, the route followed by the request packet 100 is used as the transmission route of the corresponding response packet 200.

  In view of these, as long as the request packet 100 can be received by power line communication, the second communication device 20 transmits the power line communication of the response packet 200 even if the communication quality of the power line communication is degraded. It will be adopted for transmission. As a result, the response packet 200 may be lost. Such packet loss causes a decrease in the reliability of the communication system 1 and is not preferable.

  Therefore, in the following, forward relay processing that can improve the reliability of the communication system 1 will be exemplified. FIG. 12 shows a flowchart for explaining the forward relay processing S2B according to the example. The forward relay process S2B can be used in the second communication device 20 instead of the forward relay process S2.

  According to the forward relay process 2B, when the request packet 100 is received by power line communication (step S300), the processing unit 20c, after decoding (see step S22 in FIG. 7), relays the request packet 100, In other words, it is determined whether transfer is necessary (step S302). The relay necessity determination step S302 can be configured to include, for example, the above-described relay completion determination processing S24a and relay count determination processing S24b (see FIG. 8).

  If it is determined in step S302 that relaying is not required, the processing unit 20c ends the forward relay processing S2B without relaying the received request packet 100.

  On the other hand, when it is determined in step S302 that relay is necessary, the processing unit 20c determines whether or not there is a possibility of receiving the request packet 100 having the same sequence number 104 by wireless communication thereafter ( Step S304). Such a determination can be made as follows.

  For example, the processing unit 20c first identifies the transmission source immediately before the packet 100 by referring to the route information 110 in the request packet 100 received first. Then, the processing unit 20c refers to the reception history so far from the identified immediately preceding transmission source to determine whether or not the immediately preceding transmission source further transmits the same request packet 100 by wireless communication. Determine. Note that the previous transmission source may be the first communication device 10 or may be another second communication device 20.

  For example, when the processing unit 20c receives the request packet 100, the reception history is stored in the storage unit 20c by associating the immediately preceding transmission source with information regarding whether the reception method is power line or wireless. Thus, it can be formed.

  Such reception history data may be small as compared with a configuration in which each communication device forms a database of the network configuration on the communication system and changes thereof as in the communication system of Patent Document 2. For this reason, the 2nd communication apparatus 20 and the communication system 1 can be set as the simple and cheap structure compared with the communication system of patent document 2. FIG.

  When it is determined in the determination step S304 that there is no possibility of subsequently receiving the request packet 100 having the same sequence number 104 by radio, the processing unit 20c executes the relay step S312. The relay step S312 includes, for example, the above-described steps S26, S28, and S30 (see FIG. 7). Here, since the request packet 100 is received by power line communication, the above-described wireless communication processing S30 is executed, and the request packet 100 is relayed and transmitted by wireless communication (see FIG. 7).

  On the other hand, in the determination step S304, when it is determined that there is a possibility that the request packet 100 having the same sequence number 104 is subsequently received wirelessly, the processing unit 20c performs power line communication with the immediately preceding transmission source. In other words, the reliability of performing power line communication with the immediately preceding transmission source is evaluated (step S306).

  Such evaluation can be performed by evaluating the reception quality of the request packet 100 received from the immediately preceding transmission source.

  The reception quality of the packet can be evaluated, for example, by using a function installed in the power line communication microcomputer. For example, a power line communication microcomputer (M16C / 6S group) manufactured by Renesas Technology Corp. has a function of providing information indicating the signal state of a received packet. Such reception quality information is indicated, for example, by the level of the received packet signal quality among the predetermined evaluation levels.

  In addition, according to such a product, a physical layer (first layer) and a data link layer (second layer) of an OSI (Open System Interconnection) reference model are provided. Moreover, according to the said product, in the 2nd communication apparatus 20 illustrated in FIG. 3, the part regarding control of the power line communication part 20b among the power line communication part 20b, the process part 20c, and the memory | storage part 20d, and this control Basic software parts (so-called libraries, etc.) can be configured.

  Therefore, the processing unit 20c acquires the signal quality evaluation level of the received packet 100 by the above function, and compares the evaluation level with a preset evaluation threshold value to perform power line communication with the immediately preceding transmission source. Assess the reliability of things. For example, if the acquired received signal evaluation level is higher than the evaluation threshold, it is determined that power line communication with the previous transmission source is available (in other words, acceptable communication quality), and conversely the evaluation threshold If it is below, it is determined that it is preferable to avoid power line communication with the immediately preceding transmission source.

  The evaluation threshold can be determined, for example, by a prior experiment. Specifically, if the reception quality level is low, even if the response packet 200 is transmitted by power line communication to the previous transmission source, the probability of occurrence of packet loss increases. Therefore, it is only necessary to confirm the occurrence of packet loss for each evaluation level by experiment and determine the threshold value related to the determination of acceptance / rejection of power line communication based on the experiment result.

  In the communication quality evaluation step S306, when it is determined that the power line communication with the immediately previous transmission source is available, the processing unit 20c executes the relay step S312. Here, since the request packet 100 received by power line communication is to be relayed, the above-described wireless communication processing S30 is executed, and the request packet 100 is relayed and transmitted by wireless communication (see FIG. 7).

  On the other hand, when it is determined in the communication quality evaluation step S306 that it is preferable to avoid power line communication with the immediately preceding transmission source, the processing unit 20c discards the request packet 100 previously received in power line communication (step S308). . In other words, the processing unit 20c does not relay the request packet 100.

  Instead, the processing unit 20c relays the request packet 100 having the same sequence number 104 received by wireless communication (steps S310 and S312). Here, since the request packet 100 received by wireless communication is a relay target, both the power line communication processing S30 and the wireless communication processing S30 described above are executed (see FIG. 7). Thus, the request packet 100 is relayed and transmitted by both power line communication and wireless communication.

  Note that the above-described wireless reception step S310 may occur at a timing other than the timing illustrated in the flowchart of FIG. That is, the wireless reception step S310 occurs at any timing between the power line reception step S300 and the relay step S312.

  According to the forward relay processing S2B, when the signal quality of the request packet 100 received by the power line communication method is equal to or lower than a preset threshold value, the request packet 100 is not relayed and the request packet 100 (power line received by the wireless method) (Which has the same sequence number 104 as the request packet 100 received by the communication method) is relayed.

  Here, as described above, the response packet 200 follows the path (outward path) followed by the corresponding request packet 100 in the reverse order. For this reason, the response packet 200 corresponding to the request packet 100 is avoided by avoiding the path of the power line communication method in which the received signal quality is not good, in other words, by avoiding the path having the low communication quality, Can be transmitted.

  For this reason, according to the forward relay process S2B, it is possible to prevent the response packet 200 from being lost. Therefore, the reliability of the communication system 1 can be improved.

  In the above-described forward relay processing S2B, an example has been described in which whether or not there is reception by wireless communication after reception by power line communication is determined from the reception history so far (see step S304). Hereinafter, an example in which the reception history is not used will be described. FIG. 13 shows a flowchart for explaining the forward relay process S2C according to such an example. The forward relay process S2C can be employed in the second communication device 20 instead of the forward relay processes S2 and S2B.

  The forward relay process S2C illustrated in FIG. 13 includes the steps S300, S302, and S306, but does not include the step S304. More specifically, when it is determined in step S302 that relaying is necessary, the communication quality evaluation step S306 is executed without executing step S304 for determining the possibility of wireless reception.

  In the communication quality evaluation step S306, when it is determined that the signal evaluation level of the received request packet 100 is equal to or lower than the evaluation threshold, that is, it is determined that it is preferable to avoid power line communication with the immediately preceding transmission source. In this case, the processing unit 20c waits for the request packet 100 having the same sequence number 104 to be transmitted by wireless communication (step S330).

  For example, the processing unit 20c stands by in a state where wireless reception can be accepted during a preset waiting time. The waiting time is preferably set to a length equal to or longer than the reception time difference between the power line and the radio. The reception time difference can be acquired in advance through experiments or the like. When the desired request packet 100 is received wirelessly or when the wireless reception waiting time has elapsed, the processing unit 20c ends the wireless reception waiting step S330.

  If the processing unit 20c can receive the desired request packet 100 wirelessly during the waiting time (step S332), the processing unit 20c discards the request packet 100 previously received by power line communication (step S334), and receives the request received wirelessly. The packet 100 is relayed (step S312). On the other hand, when the desired request packet 100 cannot be received wirelessly during the waiting time (step S332), the request packet 100 previously received by the power line communication is relayed (step S312).

  The other flow of the forward relay process S2C is the same as that of the forward relay process S2B.

  According to the forward relay process S2C, the same effect as the forward relay process S2B is obtained.

  In addition, according to the forward relay process S2C, it is not necessary to form data of the reception history, and therefore, a simpler configuration can be achieved as compared with the forward relay process S2B.

  FIG. 14 is a flowchart illustrating the forward relay process S2D as a further example. The forward relay process S2D can be employed in the second communication device 20 instead of the forward relay processes S2, S2B, and S2C.

  According to the forward relay process S2D, first, the request packet 100 is received (step S350). The reception step S350 is applied to both communication methods of power line communication and wireless communication. After decoding the received packet 100 (see step S22 in FIG. 7), the processing unit 20c executes the above-described relay necessity determination step S302. If it is determined in step S302 that relaying is not required, the processing unit 20c ends the forward relay processing S2D without relaying the received request packet 100.

  On the other hand, when it is determined in step S302 that relaying is necessary, the processing unit 20c evaluates the communication quality of the communication path that the received request packet 100 has traced so far (step S352). Such communication quality evaluation can be performed based on, for example, the reception quality of the request packet 100 and the number of relay stages through which the request packet 100 has passed.

  First, regarding the packet reception quality, the reception quality of the request packet 100 received by power line communication can be acquired in the same manner as in the evaluation step S306 described above.

  On the other hand, the reception quality of the request packet 100 received wirelessly can be evaluated by using, for example, an RSSI (Received Signal Strength Indication) technique for measuring the strength of the received signal. More specifically, the RSSI circuit may be provided in the wireless communication unit 20e (see FIG. 3) to measure the received signal strength, and the processing unit 20c may evaluate the measurement result. For example, the processing unit 20c determines that wireless communication with the immediately preceding transmission source is available if the acquired received signal strength is higher than a preset evaluation threshold, and conversely if it is equal to or less than the evaluation threshold. It is determined that it is preferable to avoid wireless communication with the transmission source.

  Here, for power line communication, it is possible to acquire reception quality information evaluated at multiple levels as described above. For this reason, in addition to the evaluation by comparison with the threshold value for power line communication, an evaluation value based on a multistage level may be adopted. According to this, more detailed evaluation can be performed.

  Further, the quality evaluation of the wireless communication may follow the above multi-level evaluation for the power line communication. For example, the received signal strength may be classified into multiple levels in advance, and the processing unit 20c may determine the evaluation level by comparing the acquired received signal strength with the classification. Such a classification can be used by the processing unit 20c by storing it in the storage unit 20d as data in a table format, for example. Alternatively, the classification may be incorporated into a program executed by the processing unit 20c.

  Here, the multi-stage evaluation level for wireless communication is correlated with the multi-stage evaluation level for power line communication. That is, the same evaluation level is defined so that an equivalent level of communication quality, in other words, an equivalent level of reliability, can be obtained in both wireless communication and power line communication. Thereby, mutual evaluation of wireless communication and power line communication becomes possible.

  Regarding the evaluation of the number of relay stages, it is considered that the lower the number of relay stages, the less the quality degradation of the received packet 100. For this reason, an evaluation rule that a higher evaluation level is given as the number of relay stages is smaller is defined in advance, and the processing unit 20c may perform an evaluation regarding the number of relay stages according to the evaluation rule. Note that the number of relay stages can be acquired by referring to the route information 110 in the received request packet 100.

  Then, the processing unit 20c compares the evaluation result obtained in the communication path evaluation step S352 described above with the evaluation information of the best communication path tentatively selected for the request packet 100 having the same sequence number 104 (step). S354).

  Here, the tentatively selected best route (hereinafter also expressed as “temporary best route”) refers to the communication quality of the received request packet 100 having the same sequence number 104. Is the most highly evaluated communication path.

  Further, when the request packet 100 having the new sequence number 104 is received, the information regarding the provisional best route is reset. Note that the information on the provisional best route includes, for example, information such as a device number that identifies the immediately preceding transmission source, a communication method used by the immediately preceding transmission source, and a quality evaluation result. In this case, for example, the processing unit 20c rewrites the previous transmission source device number and the communication method to “NULL” and sets the evaluation result to the lowest level, thereby resetting the provisional best route.

  In step S354, when it is determined that the communication path of the newly received request packet 100 has higher communication quality than the provisional best path, the processing unit 20c updates the provisional best path ( Step S356). That is, the communication path of the request packet 100 newly received this time is selected as the provisional best path at that time. Thereafter, the subsequent step S358 is executed.

  On the other hand, if it is determined in step S354 that the provisional best route has higher communication quality than the communication route of the newly received request packet 100, the provisional best route is held as it is. Thereafter, the subsequent step S358 is executed.

  When the communication path of the newly received request packet 100 and the provisional best path have the same evaluation, the provisional best path may be updated or may be retained as it is. .

  After step S356 or after step S354, the processing unit 20c determines whether a predetermined time set in advance has elapsed (step S358). If the predetermined time has not elapsed, the processing unit 20c returns to step S350 and waits for the next request packet 100 to arrive.

  The predetermined time is preferably set to a length equal to or longer than the reception time difference between the request packet 100 that arrives fastest and the request packet 100 that arrives latest among the request packets 100 having the same sequence number 104. . Note that such a reception time difference can be acquired in advance by an experiment or the like.

  On the other hand, if the predetermined time has elapsed in step S358, the processing unit 20c executes subsequent step S360. Even when the predetermined time has elapsed while returning to step S350 and waiting to receive the request packet 100, the processing unit 20c stops step S350 and executes step S360.

  In step S360, the processing unit 20c adopts the provisional best route held at that time as the forward route, that is, the transmission route of the corresponding response packet 200. More specifically, the request packet 100 that arrives following the provisional best route is relayed (step S312).

  According to the forward relay processing S2D, the request packet 100 that has arrived following the communication path evaluated to have the highest communication quality is relayed, and has arrived following the remaining communication path having the same sequence number. Request packet 100 is not relayed.

  Here, as described above, the response packet 200 follows the path (outward path) followed by the corresponding request packet 100 in the reverse order. Therefore, the response packet 200 corresponding to the request packet 100 can be transmitted to the first communication device 10 through the communication path evaluated as having the highest communication quality.

  For this reason, according to the forward relay process S2D, it is possible to prevent the response packet 200 from being lost. Therefore, the reliability of the communication system 1 can be improved.

  In the above example, the quality of the communication path is evaluated using two evaluation methods. That is, when the reception quality of the request packet 100 is higher than a preset threshold, an evaluation method for determining that the communication path of the request packet 100 has usable communication quality, and the request packet 100 An evaluation method is adopted in which the smaller the number of relayed stages, the higher the communication quality is evaluated.

  For this reason, communication quality can be evaluated in detail from two viewpoints. Thereby, the lost response packet 200 can be more reliably prevented, and the reliability of the communication system 1 can be further improved. Three or more evaluation methods may be combined.

  In the above, when the second communication device 20 receives the request packet 100 by power line communication, the second communication device 20 relays the request packet 100 by wireless communication. When the second communication device 20 receives the request packet 100 by wireless communication, both the wireless communication and the power line communication are used. A configuration for relaying (see steps S26, S28, and S30 in FIG. 7) was illustrated.

  On the other hand, for example, the forward relay processing S2 described above is performed so that the request packet 100 is relayed by both power line communication and wireless communication regardless of whether the request packet 100 is received by power line communication or wireless communication. , S2B, S2C, S2D may be modified.

  That is, the relay of the request packet 100 can be performed by at least one of power line communication and wireless communication in association with the communication method used to receive the request packet 100 or regardless of the received communication method.

  Moreover, although the case where the request packet 100 was relayed was illustrated above, the packet to be relayed is not limited to the request packet 100.

  Next, as an example of processing that the first communication device 10 requests from the second communication device 20 using the request packet 100, power amount acquisition processing will be described. The power amount acquisition process is a process for causing the first communication device 10 to report the power amount measured by the power measurement unit 20g of the second communication device 20. Since the electric energy changes according to the operation state of the device 51 (see FIG. 3) connected to the connection terminal 20f of the second communication device 20, it is included in the information regarding the operation of the device.

  FIG. 15 illustrates a sequence diagram of the electric energy acquisition process S10. Here, the communication devices 10, 21, and 26 illustrated in FIG. 15 will be described.

  In the example of FIG. 15, the processing unit 10c of the first communication device 10 first performs initial setting (step S100). This initial setting includes generation of a request packet 100 having a request command 106 (see FIG. 5) corresponding to the power amount acquisition process S10, clearing of a data table describing the acquisition result, and the like.

  When the request packet 100 is transmitted from the first communication device 10 (step S0), the request packet 100 reaches the second communication device 21.

  The second communication device 21 acquires the power consumption amount from the power measurement unit 20g according to the content of the request command 106 in the request packet 100, and generates a response packet 200 in which the acquired power amount is recorded in the response content information 208. It returns to the 1st communication apparatus 10 (step S4). When receiving the response packet 200, the first communication device 10 records a power amount data table of the measured power amount by the first communication device 21 based on the response content information 208 (step S102).

  The second communication device 21 relays the received request packet 100 (step S2). Such relay may be performed by any one of the forward relay processes S2B, S2C, and S2D (see FIGS. 12 to 14) instead of the forward relay process S2 (see FIG. 15).

  When the relayed request packet 100 reaches the second communication device 26, the second communication device 26 generates and transmits a response packet 200, similarly to the second communication device 21 (step S4). The transmitted response packet 200 arrives at the first communication device 10 through the return relay process S6. When receiving the response packet 200, the first communication device 10 records the power amount data table in the same manner as described above (step S104).

  In the communication system 1, the processing from the generation / transmission of the request packet 100 to the recording of the power amount reported by the second communication devices 21 and 26 is defined as one processing unit T, and the processing unit T is set a plurality of times. ,repeat. The processing unit T may be executed periodically or aperiodically.

  And the 1st communication apparatus 10 transmits the acquired electric energy information to the information management center 45 (refer FIG. 2) (step S110).

  The data transmitted to the center 45 may be all data (see FIG. 16) for each processing unit T, for example. At this time, for example, when a communication failure such as packet loss occurs and the second report cannot be received from the second communication device 21 (indicated as “−1” in FIG. 16), the data is not stored. The acquisition state may be left as it is, or unacquired data may be interpolated with other acquired data.

  Here, instead of the forward relay process S2, the packet lost can be prevented by using any of the forward relay processes S2B, S2C, and S2D (see FIGS. 12 to 14).

  In addition, the data to be transmitted to the center 45 can be limited to, for example, only representative data for each second communication device 20 by organizing all data. For example, as illustrated in FIG. 16, when different power amount data is reported from the same second communication device 22, the latest data or average data may be selected as representative data.

  In this way, when the processing unit T is executed a plurality of times, in other words, the request packet 100 including the same request command 106 is transmitted a plurality of times while changing the sequence number 104, thereby causing a communication failure or the like. However, delivery of the request packet 100 can be ensured. Further, according to the response packet 200 of a plurality of times, abundant information can be collected and information can be reliably acquired even when a communication failure or the like occurs.

  In addition, sensor state acquisition processing will be described as another example of processing that the first communication device 10 requests the second communication device 20 by using the request packet 100. The sensor state acquisition process is a process for reporting to the first communication apparatus 10 the state of various sensors as an example of the device 52, that is, information regarding the operation of the sensor. The various sensors are, for example, optical sensors, mechanical sensors, and the like, and are, for example, security sensors, sensors for detecting operation states of various devices, and the like.

  FIG. 17 illustrates a flowchart of the sensor state acquisition process S12. In the example of FIG. 17, the processing unit 10c of the first communication device 10 first performs initialization (step S120). This initial setting includes generation of a request packet 100 having a request command 106 (see FIG. 5) corresponding to the sensor state acquisition process S12, clearing of a data table describing the acquisition result, and the like.

  When the request packet 100 is transmitted from the first communication device 10 to each second communication device 20, each second communication device 20 detects the state of a sensor connected so as to be communicable. Then, each second communication device 20 transmits a response packet 200 in which the detection result is recorded in the response content information 208 to the first communication device 10. Thereby, the sensor connected to the communication system 1 is scanned (step S122).

  Then, the first communication device 10 receives the response packet 200 from each second communication device 20, collects the scan results in, for example, a data table based on each response content information 208 (see FIG. 18), It is determined whether or not a sensor exists (step S124). As a result of the determination, if there is an on-state sensor, the first communication device 10 reports to the center (for example, security center) 45 (step S126), and then returns to step S120. On the other hand, when there is no sensor in the ON state, the first communication device 10 returns to the above step S120 without performing the center report step S126.

  Contrary to the above, when there is a sensor in an off state, the center 45 can be notified.

  Here, a plurality of sensors may be connected as a device 52 to one second communication apparatus 20 (for example, in the case of wireless connection). In this case, the response content information 208 may be generated for each sensor, or one response content information 208 may be generated by collecting some or all of the plurality of sensors.

  In addition, one sensor may be connected as a device 52 to a plurality of second communication apparatuses 20 (for example, in the case of wireless connection). In this case, it is preferable that the first communication device 10 employs the latest of the acquired data.

  In addition, although the case where the device 52 is various sensors was illustrated above, the device 52 may be various information terminals, for example. In this case, the information acquired and held by the information terminal can be collected by the first communication device 10 via the second communication device 20. Examples of the information terminal include health management devices such as a weight scale and a blood pressure monitor.

  In the above, power line communication has been exemplified, but other wired communication can be applied to the communication system 1 instead of power line communication. In contrast, power line communication generally tends to degrade communication performance due to noise generated by devices connected to the power line (in other words, the stability of communication quality is low), so power line communication and wireless communication are used in combination. According to the communication system 1, good communication (in other words, highly reliable communication) can be obtained as a whole system.

  Further, the communication system 1 illustrated above can be modified to a configuration using a plurality of types of wireless systems. In that case, for example, a plurality of types of radio systems may be configured to include radio systems of a plurality of standards, or may be configured to include radio systems that have the same standard but have a plurality of channels. .

  Similarly, the communication system 1 illustrated above can be modified to a configuration using a plurality of types of wired systems. In that case, for example, a plurality of types of wired systems may be configured to include a wired system of a plurality of standards, or may be configured to include a wired system that has the same standard but has a plurality of channels. .

  Note that both wireless and wired systems have various features depending on the standard (for example, excellent communication quality stability, low power consumption, etc.), so communication is possible depending on the situation so that each feature can be utilized. You may employ | adopt the structure which switches a system.

DESCRIPTION OF SYMBOLS 1 Communication system 10 1st communication apparatus 10b Power line communication part 20, 21-26 2nd communication apparatus 20b Power line communication part 20e Wireless communication part 100 Request packet (1st packet)
104 Sequence number (identification information)
110 Outbound route information 200 Response packet (second packet)
210 Return route information S2, S2B, S2C, S2D Outward relay processing S6 Inward route relay processing

Claims (6)

A first communication device;
A plurality of second communication devices configured to be able to transmit and receive packets by a plurality of communication means including both a wired method and a wireless method, and having a function of relaying received packets;
Each of the plurality of second communication devices is
When relaying the first packet transmitted from the first communication device, information regarding the relaying by the second communication device and the type of communication means used for relaying among the plurality of communication means Information in the first packet as outbound route information,
When generating a second packet for responding to the first packet, copy the forward route information and record it in the second packet as return route information;
When relaying the second packet, the second packet is relayed so as to follow the route followed by the first packet based on the return route information in reverse order,
Each of the plurality of second communication devices is
When the first packet having the same identification information is received by both the wired method and the wireless method, and the signal quality of the first packet received by the wired method is below a preset threshold, Relaying the first packet received by the wireless method without relaying the first packet received by the wired method;
Communications system. A first communication device;
A plurality of second communication devices configured to be able to transmit and receive packets by a plurality of communication means including both a wired method and a wireless method, and having a function of relaying received packets;
Each of the plurality of second communication devices is
When relaying the first packet transmitted from the first communication device, information regarding the relaying by the second communication device and the type of communication means used for relaying among the plurality of communication means Information in the first packet as outbound route information,
When generating a second packet for responding to the first packet, copy the forward route information and record it in the second packet as return route information;
When relaying the second packet, the second packet is relayed so as to follow the route followed by the first packet based on the return route information in reverse order,
Each of the plurality of second communication devices is
When a plurality of first packets having the same identification information are respectively received by the plurality of communication means, the communication quality of the communication path followed by the plurality of first packets is evaluated according to a predetermined evaluation method, and the communication quality Relaying the first packet arriving along the communication path evaluated to be the highest, and not relaying the first packet arriving along the remaining communication path,
Communications system. A communication system according to claim 2,
The evaluation method for the communication quality is:
An evaluation method for determining that the communication path of the first packet has usable communication quality when the reception quality of the first packet is higher than a preset threshold;
And an evaluation method in which the communication quality is evaluated higher as the number of relay stages through which the first packet has passed is smaller. The communication system according to any one of claims 1 to 3,
The plurality of communication means includes a power line communication means and at least one type of wireless communication means. A communication device as a slave station that constitutes a communication system with a master station,
It is configured to be able to send and receive packets by multiple communication means including both wired and wireless methods,
When relaying the first packet transmitted from the master station, information indicating that the packet is relayed by the communication device and information regarding the type of communication means used for relay among the plurality of communication means Record in the first packet as route information,
When generating a second packet for responding to the first packet, copy the forward route information and record it in the second packet as return route information;
When relaying the second packet, the second packet is relayed so as to follow the route followed by the first packet based on the return route information in reverse order,
When the first packet having the same identification information is received by both the wired method and the wireless method, and the signal quality of the first packet received by the wired method is below a preset threshold, Relaying the first packet received by the wireless method without relaying the first packet received by the wired method;
Communication device. A communication device as a slave station that constitutes a communication system with a master station,
It is configured to be able to send and receive packets by multiple communication means including both wired and wireless methods,
When relaying the first packet transmitted from the master station, information indicating that the packet is relayed by the communication device and information regarding the type of communication means used for relay among the plurality of communication means Record in the first packet as route information,
When generating a second packet for responding to the first packet, copy the forward route information and record it in the second packet as return route information;
When relaying the second packet, the second packet is relayed so as to follow the route followed by the first packet based on the return route information in reverse order,
When a plurality of first packets having the same identification information are respectively received by the plurality of communication means, the communication quality of the communication path followed by the plurality of first packets is evaluated according to a predetermined evaluation method, and the communication quality Relaying the first packet arriving along the communication path evaluated to be the highest, and not relaying the first packet arriving along the remaining communication path,
Communication device.

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