JP3985828B2 - Communication route construction method and communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of constructing a communication route where traffics required for constructing the communication route can be made relatively small and where a relatively small amount of data concerning the communication routes is required to be stored at terminals. <P>SOLUTION: The communication route constructing method of this invention comprises a step S2 of enabling a terminal to transmit an H packet, which contains communication quality information indicating the quality of communication kept through a communication route from the terminal itself to its host terminal and vice versa, to a communication network with a broadcast communication, steps S4, S7, and S10 of making an H packet receiving terminal acquire the quality of communication kept through a communication route from the H packet sending terminal to the terminal itself and also acquire the quality of communication kept through a communication route from the terminal itself to the sending terminal of a notice communication packet, and steps S13 and S14 of calculating the quality of communication kept through a communication route from the terminal to the host terminal and vice versa on the basis of the two-way communication quality acquired by the H packet receiving terminal through the steps 4, 7, and 10 and the communication quality information contained in the received H packet and of constructing a communication route from the terminal to the host terminal and vice versa only when the calculated communication quality meets the prescribed requirements. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to a first communication terminal and a second communication terminal in a communication network including a first communication terminal (parent communication terminal) and a plurality of second communication terminals (child communication terminals). It is related with the construction method of the communication route between.

  In a communication network including a plurality of communication terminals connected to a predetermined communication network, a communication terminal (hereinafter referred to as “terminal”) communicates with a terminal that cannot directly communicate with the own terminal by relaying a communication signal. The method of doing is known. In such a communication method, a communication route between terminals is constructed in response to a change in the network topology of the communication network due to a change in the communication state of the terminal, such as a terminal in which communication was possible becomes impossible. However, it is necessary for communication between the terminals.

  For example, in a wireless LAN using radio as a transmission path between each terminal, since the terminal moves in the network, there is a characteristic that the network topology is easily changed, and each terminal corresponds to a change in the network topology of the communication network. It is particularly necessary to establish a communication route between them. In a wireless LAN, an ad hoc network is used as one method for constructing a communication route between terminals in response to a change in the network topology of the communication network. The ad hoc network employs a form (multi-hop communication) in which a large number of terminals are connected to each other without intervention of an access point while using a technology such as IEEE 802.11x. In an ad hoc network, each terminal holds a routing table in which a communication route is registered in advance in a storage unit, and performs communication with a proactive type that obtains a communication route between the terminals by referring to the routing table. There is a reactive type in which a data transmission source terminal searches for a communication route to a data reception destination terminal and constructs a communication route.

Further, in recent years, a predetermined communication protocol (for example, an SCP (developed by Microsoft Corporation) using a power line as a communication line between each electric device (corresponding to the terminal) such as a lighting apparatus electrically connected to the power line. 2. Description of the Related Art A power line carrier communication network (hereinafter abbreviated as “PLC network”) that performs power line carrier communication (hereinafter abbreviated as “PLC (Power Line Communication)”) using Simple Control Protocol) has become widespread. Even in a PLC network, a method of performing communication with a terminal that cannot directly communicate with its own terminal by relaying a communication signal is known (see, for example, Patent Document 1). In addition, there is no known method for communicating between terminals relayed by a plurality of terminals. In addition, in the PLC network, since communication is performed via a power line, a noise component is superimposed on an electric signal, and the terminal is likely to be in a state where communication is impossible. Since the connection status of the terminal to the power line is easily changed, the network topology in the communication network is easily changed like the wireless LAN.
Japanese Patent No. 3330329

  In the above-described ad hoc network, both the proactive type and the reactive type are used in a communication network in which the communication speed between terminals and the capacity of a memory such as a RAM (Random Access Memory) of each terminal are smaller than a predetermined level. In many cases, it is difficult to suitably perform communication between terminals. In particular, in the above-described PLC network, the communication speed between the terminals is usually as small as several kbps, and the memory capacity of the terminals is usually as small as several kbytes. Therefore, even if an ad hoc network is adopted for such a PLC network, Communication between terminals cannot be performed satisfactorily.

  That is, in the proactive type, it is necessary to reflect the change in the network topology in the routing table. For this reason, a communication packet (Hello Packet, Hello Packet (hereinafter abbreviated as “H packet”) must be frequently transmitted / received. However, when the communication speed between terminals is low, such as in a PLC network, the H packet can be frequently transmitted / received. However, it is difficult to reflect changes in the network topology in the routing table. In the reactive type, a communication route is searched every time communication is performed. Therefore, when the communication speed between terminals is low, such as in a PLC network, a long time is required for searching the communication route. Resulting in.

  In addition, in an autonomous distributed network in which each terminal can be connected to each other like an ad hoc network, all communication quality (Signal Quality, hereinafter abbreviated as “SQ”) between the terminal and the terminal that can communicate with the terminal is stored in memory. I need to remember. For this reason, it becomes necessary to mount a large-capacity memory in each terminal, and costs increase. Therefore, it is difficult to adopt a self-supporting distributed network as a communication network such as a PLC.

  Therefore, in order to reduce the memory capacity of each terminal, a master-slave type that consists of a parent terminal and a child terminal and communicates between the parent terminal and the child terminal is adopted instead of an autonomous distributed network. It is preferable to do. The reason for this is that in the master-slave type, the child terminal only needs to store the SQ between the neighboring terminals and the SQ with the parent terminal that is relayed by a communication route that is better than the upper predetermined rank in the memory. This is preferable because the data capacity stored in the memory is reduced.

  However, in the case of adopting the master-slave type, only the SQ between adjacent terminals that are relayed by a communication route that is higher than the upper predetermined rank in the SQ with the parent terminal is stored in the memory. The same communication route is used for both the communication route to the child terminal and the communication route from the child terminal to the parent terminal, and each terminal needs to acquire the SQ from both directions in the communication route with the parent terminal. It becomes. For this reason, each terminal must exchange SQ by unicast in order to acquire SQ from both directions, and a huge amount of traffic is generated. In a PLC with a low communication speed, a communication route in a short time can be obtained. Construction becomes difficult.

  The present invention has been made in view of the above circumstances, and can construct a communication route that can relatively reduce traffic for constructing a communication route and that has a relatively small amount of data related to the communication route to be stored in the terminal. It is an object to provide a method and a communication terminal.

To achieve the above-described object, communication between a parent communication terminal and the child communication terminal in a communication network including a parent communication terminal and a plurality of child communication terminals according to an aspect of the present invention. In the communication route construction method for constructing a route, the communication terminal broadcasts a notification communication packet including communication quality information indicating communication quality in a communication route between the communication terminal and the parent communication terminal to the communication network. A communication quality notification step to be transmitted by communication, and when the child communication terminal receives the notification communication packet, obtains the communication quality from the transmission communication terminal that transmitted the notification communication packet to the own communication terminal A communication quality acquisition step for acquiring communication quality from the communication terminal to the transmission source communication terminal that transmitted the notification communication packet; and a child receiving the notification communication packet. Based on the two-way communication quality acquired in the communication quality acquisition step and the communication quality information included in the received notification communication packet, the communication terminal is connected with the parent communication terminal and the own communication terminal. calculating a communication quality between the communication quality the calculated only when a predetermined condition is satisfied, and a communication route construction step of constructing a communication route between the communication terminal and the own communication terminal of the parent, the communication The quality acquisition step includes the communication quality from the communication terminal that is the transmission source of the notification communication packet obtained based on the received notification communication packet to the own communication terminal, and the communication included in the received notification communication packet. based on the quality information, calculates a provisional communication quality between the communication terminal and the own communication terminal of the parent provisional communication quality thus calculated only when a predetermined condition is satisfied, to be executed And butterflies.

In the communication route construction method described above, the predetermined condition in the communication quality acquisition step is that the calculated temporary communication quality is equal to or higher than a predetermined reference value.

In the communication route construction method described above, the predetermined condition in the communication quality acquisition step, from the upper of the temporary communication quality can be calculated between the communication terminal and the own communication terminal of the provisional communication quality the calculated parent It is within a predetermined order.

And in these above-mentioned communication route construction methods, the communication quality acquisition step is executed only when the reception probability of the notification communication packet within a predetermined time is not less than a predetermined reference value. To do.

In the above-described communication route construction methods, the predetermined condition in the communication route construction step is that the calculated communication quality is equal to or higher than a predetermined reference value .

Furthermore, in the above-described communication route construction methods, the predetermined condition in the communication route construction step is that the calculated communication quality is higher than the communication route constructed between the parent communication terminal and the own communication terminal. It is within a predetermined order .

And in these above-mentioned communication route construction methods, the communication quality notification step is executed only when a communication route is established between the own communication terminal and the parent communication terminal. .

Further, in these communication route construction methods described above, the communication quality acquisition step includes the communication route construction step in which a communication route between the parent communication terminal and the own communication terminal whose communication quality is equal to or higher than a predetermined reference value. if it is built by the you characterized in that its execution is prohibited.

  And in these above-mentioned communication route construction methods, the communication quality acquisition step transmits the notification communication packet based on the received notification communication packet when the child communication terminal receives the notification communication packet. A first step of obtaining communication quality from the transmission source communication terminal to the own communication terminal, and a child communication terminal receiving the notification communication packet to the transmission source communication terminal transmitting the notification communication packet from the own communication terminal A second step of returning a response communication packet for requesting notification of the communication quality to the transmission source communication terminal that has transmitted the notification communication packet, and the transmission source communication terminal that has transmitted the notification communication packet is the notification communication packet. The child communication terminal that has received the notification communication packet based on the response communication packet received from the child communication terminal that has received A communication quality notification communication packet including the communication quality is returned to the child communication terminal that has received the notification communication packet, and a child step that has received the notification communication packet The communication terminal includes a fourth step of receiving the communication quality notification communication packet from a communication terminal of a transmission source that has transmitted the notification communication packet.

  Further, in these communication route construction methods described above, the communication quality acquisition step includes transmitting the notification communication packet based on the received notification communication packet when the child communication terminal receives the notification communication packet. A first step of obtaining communication quality from the original communication terminal to the own communication terminal, and each communication at a transmission source of a plurality of notification communication packets received by a child communication terminal that has received the notification communication packet within a predetermined time A response communication packet for collectively requesting notification of each communication quality to each communication terminal at a transmission source that has transmitted the plurality of notification communication packets from the own communication terminal to the terminal is transmitted to the communication network by broadcast communication. 2 and when the communication terminal that has received the response communication packet is addressed to its own device, the child that has transmitted the response communication packet Based on the response communication packet received from the communication terminal, the communication quality notification communication packet including the communication quality is obtained for the communication quality from the child communication terminal that has transmitted the response communication packet to the own communication terminal. And a fourth step in which the child communication terminal that has received the notification communication packet receives the communication quality notification communication packet from the communication terminal that has received the response communication packet. It is characterized by providing.

  Furthermore, in the above-described communication route construction methods, the response communication packet is also used as the notification communication packet.

  And in these above-mentioned communication route construction methods, when the child communication terminal receives the notification communication packet, the communication quality acquisition step transmits the notification communication packet based on the received notification communication packet. A first step of obtaining communication quality from the original communication terminal to the own communication terminal; and a child communication terminal that has received the notification communication packet transmits the notification communication packet from the own communication terminal to the transmission source communication terminal. A second step of returning a response communication packet for requesting notification of communication quality to the transmission source communication terminal that has transmitted the notification communication packet; and a transmission source communication terminal that has transmitted the notification communication packet Based on the response communication packet received from the received child communication terminal, the child communication terminal that received the notification communication packet Each communication at the transmission source that transmitted the plurality of response communication packets obtained to each communication terminal at the transmission source of the plurality of response communication packets received within a predetermined time while obtaining communication quality to the own communication terminal A third step of transmitting a communication quality notification communication packet that summarizes the notification of each communication quality from the terminal to the self-communication terminal by broadcast communication to the communication network; and a child communication terminal that has received the notification communication packet, When the communication quality notification communication packet is received, the communication quality from the transmission source communication terminal that has transmitted the notification communication packet corresponding to the own device included in the communication quality notification communication packet to the own communication terminal is acquired. And a fourth step.

  In the above-described communication route construction methods, the communication quality notification communication packet is also used as the notification communication packet.

  Further, in these communication route construction methods, the communication route construction step further includes a route determination communication packet including a communication route between the constructed parent communication terminal and the own communication terminal to the parent communication terminal. The route determination communication packet is also used as the notification communication packet.

According to another aspect of the present invention, a communication terminal that establishes a communication route between a parent communication terminal and a communication route between the own communication terminal and the parent communication terminal in the communication network. A communication quality notification means for transmitting a notification communication packet including communication quality information indicating to the communication network by broadcast communication, and the notification obtained based on the received notification communication packet when the notification communication packet is received Based on the communication quality from the communication terminal that is the transmission source of the communication packet to the own communication terminal, and the communication quality information included in the received notification communication packet, between the parent communication terminal and the own communication terminal of calculating the provisional communication quality, temporary communication quality thus calculated only when a predetermined condition is satisfied, communication products from the notification source of the communication terminal that has transmitted the communication packet to the own communication terminal Communication quality acquisition means for acquiring communication quality from the communication terminal to the transmission source communication terminal that transmitted the notification communication packet, and bidirectional communication quality acquired by the communication quality acquisition means, and When communication quality between the parent communication terminal and the own communication terminal is calculated based on the communication quality information included in the received notification communication packet, and the calculated communication quality satisfies a predetermined condition And a communication route construction means for constructing a communication route between the parent communication terminal and the own communication terminal.

  In the communication route construction method and the communication terminal for constructing the communication route with the parent communication terminal having such a configuration, in order to acquire the communication quality from both directions between the parent communication terminal and the child communication terminal, Traffic in the communication network can be reduced.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, in each figure, the structure which attached | subjected the same code | symbol shows that it is the same structure, The description is abbreviate | omitted.

(First embodiment)
Below, 1st Embodiment for implementing this invention is described using FIGS. 1-7. In this embodiment, the communication route construction method of the present invention is used for a PLC network.

  FIG. 1 is a diagram showing a configuration of a power line carrier communication network 1 according to the first embodiment of the present invention. A power line carrier communication network (hereinafter abbreviated as “PLC network”) 1 is used in, for example, a building for an apartment house, and a plurality of communication terminals 10 (10a, 10b) connected by power lines L (L1, L2). It is configured with. A plurality of communication terminals (hereinafter abbreviated as “terminals”) 10 includes one terminal 10a serving as a parent (hereinafter referred to as “parent terminal 10a”) and a plurality of other terminals 10b serving as children (hereinafter referred to as “terminal”). Child terminal 10b ").

  The power line L is an example of a predetermined communication network, and includes a main line L1 introduced into the building from a distribution board (not shown), and one or a plurality of branch lines L2 branched from the main line L1. The The parent terminal 10a is connected to the trunk line L1, and the child terminal 10b is connected to the branch line L2. These terminals 10 perform PLC using a predetermined communication protocol between the terminals 10 via the trunk line L1 and the branch line L2, thereby causing the parent terminal 10a to acquire predetermined information about the child terminal 10b, for example. Thus, remote monitoring of the child terminal 10b by the parent terminal 10a is performed. The predetermined protocol is, for example, SCP or Echonet.

  FIG. 2 is a diagram showing a communication route established between the terminals 10 in the PLC network 1 shown in FIG. An arrow line 11 indicates a communication route established between the terminals 10 using the communication route construction method according to the present invention. The child terminal 10b is relayed directly to the parent terminal 10a or to another child terminal 10b. A communication route between the terminals 10 is established so that communication is possible.

  In this embodiment, each child terminal 10b searches for a communication route with better communication quality with the parent terminal 10a, that is, a communication route that allows better communication with the parent terminal 10a, and constructs a communication route.

  The reason why the communication route is constructed in the PLC network 1 is as follows. That is, in PLC, since the power line is used, the transmission environment is deteriorated due to noise generated by other home appliances connected to the power line or reduction in impedance of the power line L due to the connection of other home appliances. The communication error rate increases, and in some cases, a situation in which communication is impossible occurs. And the transmission environment changes dynamically according to the connection state (insertion / extraction) of the other household electrical appliances to the power line L and the movable state of the terminal, and as a result, the communication availability state also changes dynamically. For this reason, in the PLC network 1, the network topology is not fixed but easily changes. In the present embodiment, the child terminal 10b searches and constructs a communication route with the parent terminal 10a so that the communication between the parent terminal 10a and the child terminal 10b can be satisfactorily performed so as to cope with a change in the network topology. It can be done.

  FIG. 3 is a block diagram of the terminal 10 shown in FIG. In the present embodiment, the same terminal is used as the parent terminal 10a and the child terminal 10b. For example, the terminal 10 is set to “parent” by setting means (an example of mode setting means) such as a jumper switch or a changeover switch. When set, it functions as the parent terminal 10a, and when set to “child”, it functions as the child terminal 10b.

  The terminal 10 includes a storage unit 110, a power line carrier communication interface unit (hereinafter abbreviated as “PLC interface unit”) 120, and a control unit 130. The storage unit 110 functionally includes a table storage unit 111, stores each program such as a control program for operating the terminal 10, information necessary for the execution of each program, and the so-called control unit 130. It is also a working memory. The storage unit 110 stores each program, information necessary for the program, and the like. For example, a nonvolatile storage element such as a ROM (Read Only Memory) or a rewritable nonvolatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory). A storage element and a volatile storage element such as a RAM (Random Access Memory) serving as a working memory are provided.

  The table storage unit 111 is an area for storing data in a table format. When the terminal 10 is the parent terminal 10a, communication for registering all communication routes between the terminals 10 constructed in the PLC network 1 is performed. Store the route data table. On the other hand, when the terminal 10 is the child terminal 10b, the table storage unit 111 stores the communication quality between the terminal 10 and the other terminal 10 and the other terminals 10 with which the terminal 10 can communicate, A communicable terminal data table D representing the communication quality level between the terminal 10 and the parent terminal 10a via the other terminal 10 is stored.

  FIG. 4 is a diagram illustrating an example of the communicable terminal data table D. As illustrated in FIG. The communicable terminal data table D is data in a table format including a data table representing the terminal ID, SQ between the terminal 10 and the terminal 10 corresponding to the terminal ID, the communication cost value, and the acquisition time of the communication cost value. It is. The terminal ID is an identifier unique to each terminal 10 for identifying the terminal 10 with which the communication route is established with the terminal 10. The terminal ID is one or a plurality of code strings, such as a MAC (Media Access Control) address. In the present embodiment, in the communicable terminal data table D, the terminal IDs of the parent terminals 10a to 10b or the child terminals 10b having communication paths established with the parent terminals 10a (hereinafter referred to as “upper terminals”) are Registered as a communication route.

  The SQ represents the received signal strength of the communication signal received from the terminal 10 identified by the terminal ID at several levels (for example, 10 levels). The smaller the value, the smaller the attenuation of the communication signal. The quality is high. In the communicable terminal data table D, the SQ from the terminal 10 corresponding to the terminal ID to the terminal 10 and the SQ from the terminal 10 to the terminal 10 corresponding to the terminal ID (terminal corresponding to the terminal 10 and the terminal ID) 10 is registered.

The communication cost value is an example of a communication quality level with the parent terminal 10a, and represents a communication state with the parent terminal 10a. For example, the communication cost value is obtained by the following equation (1).
(Communication cost value) = Ka × (sum of SQs between child terminal 10b and upper terminal 10 via communication with parent terminal 10a) + Kb × (hop count) Expression (1)
Here, Ka and Kb are weighting factors for deciding which one of (the sum of SQs between the child terminal 10b and the upper terminal 10 via communication with the parent terminal 10a) and (the number of hops) should be emphasized. It is. The number of hops is the number of child terminals 10b (including the own terminal 10) that pass through communication with the parent terminal 10a.

  For example, when communication is performed between the main terminal 10 and the parent terminal 10a via two child terminals 10b, the SQ between the parent terminal 10a and the highest child terminal 10b is “3”, and the highest child terminal. When the SQ between the terminal 10b and the terminal 10b one higher than the terminal 10 is "4", and the SQ between the terminal 10b one higher than the terminal 10 and the terminal 10 is "5" The sum of SQs between the child terminal 10b and the upper terminal 10 via the communication with the parent terminal 10a is 3, and the sum of SQs is “3” + “4” + “5”, which is 12. Therefore, the communication cost value is obtained by 12 × Ka + 3 × Kb. As for the communication cost value, the smaller the value is, the better the communication quality is. If a communication route is not established with the parent terminal 10a and communication is impossible, the communication cost value is “0”.

  Returning to FIG. 3, the PLC interface unit 120 is a communication interface circuit that performs PLC with another terminal 10 using the power line L. For example, the PLC transmits a communication signal via the power line L by transmitting a high-frequency communication signal superimposed on a commercial-frequency power waveform, or by separating and receiving the high-frequency communication signal from the power waveform. This is a communication method for transmitting and receiving.

  The control unit 130 includes, for example, a microprocessor and its peripheral circuits, and is a process for constructing a communication route between the parent terminal 10a and the child terminal 10b (hereinafter referred to as “communication route construction process”). Is functionally provided with a communication processing unit 131, a table processing unit 132, and a hello packet transmission timer unit (hereinafter abbreviated as “H packet transmission timer unit”) 133.

  The communication processing unit 131 performs communication route construction processing for constructing a communication route to the parent terminal 10 a by transmitting and receiving communication signals to and from other terminals 10 using the PLC interface unit 120 and performing operations described later.

  The table processing unit 132 manages the communication route data table or the communicable terminal data table D stored in the table storage unit 111 as described later.

  The H packet transmission timer unit 133 is a time measuring unit that measures the passage of time, and notifies the communication processing unit 131 of the arrival of the transmission timing of the H packet (for example, the transmission time of the H packet) at predetermined time intervals.

  FIG. 5 is a flowchart showing an example of a communication route construction process of the terminal 10 shown in FIG. This process is executed when, for example, the terminal 10 is turned on. First, the communication processing unit 131 determines whether or not the H packet transmission time has arrived and whether or not a communication packet has been received (S1).

  As a result of the determination, when the arrival of the transmission time of the H packet is notified from the H packet transmission timer unit 133 (H packet transmission time), the communication processing unit 131 creates an H packet, For example, the broadcast is transmitted to the PLC network 1 (S2), and the process returns to step S1.

  The H packet is an example of a notification communication packet, and is transmitted from each terminal 10 to the PLC network 1 by broadcast communication, for example, broadcast at predetermined time intervals, so that the terminal 10 This is a communication packet indicating survival. The H packet is a communication packet including data indicating an operation code, a transmission source terminal ID, a sequence number, a communication cost value, and the number of hops, for example, as illustrated in FIG. The operation code is an identifier representing the type of this communication packet. For example, as the type of this communication packet, an H packet, a response packet described later, an SQ notification packet, and a route determination packet are indicated. The terminal ID of the transmission source is the terminal ID of the terminal 10 that is the transmission source of the communication packet. The sequence number is a randomly set number, and the same number is assigned to communication packets related to the H packet. Here, the data representing the number of hops represents the number of hops used for calculating the communication cost value. When the terminal 10 is the parent terminal 10a, the communication cost value is the smallest and the hop count is zero.

  Returning to FIG. 5, when the communication packet is received as a result of the determination in step S1 (packet reception), the communication processing unit 131 identifies what type of the received communication packet is (S3). This identification is performed, for example, by referring to an operation code included in the communication packet.

  If the communication packet is identified as a response packet, the communication processing unit 131 executes step S4 described later. If the communication packet is identified as a route determination packet, the communication processing unit 131 is described later. In step S5, when the communication packet is identified as an H packet, the communication processing unit 131 executes step S6 described later. FIG. 6B shows an example of a response packet, and FIG. 6C shows an example of a route determination packet. The response packet is an example of a response communication packet, and includes an operation code, a transmission source terminal ID, and a sequence number. The route determination packet includes data representing an operation code, a transmission source terminal ID, a sequence number, a communication cost value, and an upper terminal ID. As the sequence number, the same number as the H packet that responds or the SQ notification packet that responds is assigned. The host terminal ID is the ID of the terminal 10 through which the terminal 10 that is the transmission source of the route determination packet communicates with the terminal 10. When the higher-level terminal ID is transmitted from the terminal 10 that is the transmission source of the route determination packet, only the first higher-level terminal ID is included. In this case, the terminal IDs after the second upper terminal ID are given.

  In step S4, the communication processing unit 131 outputs the response packet to the table processing unit 132, and from the received signal strength of the response packet to the table processing unit 132, the SQ from the terminal 10 at the transmission source of the response packet to the terminal 10 is transmitted. To get. Then, the communication processing unit 131 notifies the table processing unit 132 of the acquired SQ. The communication processing unit 131 creates an SQ notification packet that is a communication packet including data indicating the notified SQ. The communication processing unit 131 transmits the created SQ notification packet to the terminal 10 that has transmitted the response packet by unicast, and then returns the process to step S1.

  FIG. 6D shows an example of the SQ notification packet. The SQ notification packet includes an operation code, a transmission source terminal ID, a sequence number, and data representing an SQ from the transmission source terminal 10 to the terminal 10 of the response packet. The same number as the response packet received in step S3 is assigned to the sequence number.

  In step S5, when the terminal 10 is the child terminal 10b, the communication processing unit 131 refers to the communicable terminal data table D and adds the terminal ID of the next higher-level terminal 10 to the received route determination packet. Then, it transmits to the next upper terminal 10 by unicast. When the terminal 10 is the parent terminal 10a, the communication processing unit 131 outputs the received route determination packet to the table processing unit 132, and causes the table processing unit 132 to update the communication route table. The update of the communication route table includes registering the terminal ID of the transmission source and the upper terminal ID included in the route determination packet in the communication route table as a built communication route. Thereafter, the communication processing unit 131 returns the process to step S1.

  In step S6, the communication processing unit 131 refers to the communication cost value included in the received H packet, and determines whether the terminal 10 that is the transmission source of the H packet is the terminal 10 for which a communication route has been established with the parent terminal 10a. It is determined whether it is the route construction terminal 10 or not. Here, when the communication cost value is “0”, it is determined that the route construction terminal 10 is not used. In other words, when the communication cost value is not 0, the route construction terminal 10 is determined. Thereafter, the communication processing unit 131 determines whether the terminal 10 is not the parent terminal 10a. Here, when the terminal 10 is receiving the H packet from the parent terminal 10 a, it is determined that the parent terminal 10 a is necessarily the route construction terminal 10. When the H packet transmission source terminal 10 that is the transmission source terminal 10 that has transmitted the H packet does not determine that it is the route construction terminal 10 or if this terminal 10 does not determine that it is not the parent terminal 10a (NO in S6) The communication processing unit 131 returns this processing to step S1, determines that the terminal 10 is not the parent terminal 10a, and determines that the H packet transmission source terminal 10 is the route construction terminal 10 (YES in S6). ), The communication processing unit 131 creates a response packet with the same sequence number as the sequence number included in the H packet, and transmits the response packet to the H packet transmission source terminal 10 (S7).

  Then, the communication processing unit 131 notifies the H packet to the table processing unit 132, and the communication cost value and the number of hops from the data indicating the communication cost value and the number of hops included in the input H packet to the table processing unit 132. To get. The communication processing unit 131 further causes the table processing unit 132 to acquire the SQ from the H packet transmission source terminal 10 to the terminal 10 based on the received signal strength of the input H packet, and temporarily stores it in the storage unit 110. Memorize. The process of step S7 is an example of a process for acquiring a bidirectional SQ between the terminal 10 that is the source of the H packet and the terminal 10 itself.

  Further, by executing Step S6, the communication processing unit 131 executes Step S7 only when the H packet transmission source terminal 10 is the route construction terminal 10, and thus traffic in the PLC network 1 is increased unnecessarily. Can be prevented. The PLC network 1 is a master-slave network, and it is an object of the communication route construction process that the child terminal 10b secures a communication route with the parent terminal 10a. Here, the communication processing unit 131 executes a process of acquiring a bidirectional SQ between the H packet transmission source terminal 10 and the own terminal 10 only when the H packet transmission source terminal 10 is the route construction terminal 10. When the H packet transmission source terminal 10 is not the route construction terminal 10, the process for acquiring the bidirectional SQ between the H packet transmission source terminal 10 and the own terminal 10 is not executed. Therefore, an increase in traffic in the PCL network 1 can be suppressed.

  The communication processing unit 131 determines whether or not to receive the SQ notification packet within a predetermined time after transmitting the response packet (S8), and does not determine that the SQ notification packet is received within the predetermined time (NO in S8). The present process returns to step S1. If the communication processing unit 131 determines that the SQ notification packet is received within a predetermined time (YES in S8), whether or not the received SQ notification packet includes the same sequence number as the response packet transmitted in step S7. Is determined (S9). For example, when the response packet is transmitted, the sequence number is temporarily stored in the storage unit 110 and the same sequence number is referred to by referring to the sequence number. This is done depending on whether or not the sequence number is included. If it is not determined that the received SQ notification packet includes the same sequence number as the transmitted response packet (NO in S9), the communication processing unit 131 returns this processing to step S8 again, and receives the received SQ notification packet. However, the communication processing unit 131 notifies the table processing unit 132 of the received SQ notification packet, based on the SQ notification packet, when it is determined that it includes the same sequence number as the transmitted response packet (YES in S9). The communication cost value is calculated (S10).

  The communication cost value is calculated by, for example, the communication cost value and the number of hops from the parent terminal 10a to the H packet transmission source terminal 10 temporarily stored in the storage unit 110, and the SQ (H packet transmission source terminal 10 (SQ to terminal 10) and SQ (SQ from terminal 10 to SQ notification packet transmission source terminal 10) obtained from data representing SQ included in the input SQ notification packet. The That is, the communication cost value is calculated by (communication cost value from parent terminal 10a to H packet transmission source terminal 10) + Ka × (the larger SQ) + Kb × 1.

  The communication processing unit 131 causes the table processing unit 132 to determine whether or not the calculated communication cost value is equal to or higher than the upper predetermined rank as compared with the communication cost value registered in the communicable terminal data table D ( S11). Here, the calculated communication cost value being equal to or higher than the upper predetermined rank corresponds to a case where the acquired communication quality with the parent terminal 10a satisfies a predetermined condition.

  When it is not determined that the calculated communication cost value is higher than the upper predetermined rank compared to the communication cost value registered in the communicable terminal data table D (NO in S11), the communication processing unit 131 The data used in the current communication route construction process, which is temporarily stored in the storage unit 110 such as the calculated communication cost value, is discarded (S12).

  When it is determined that the calculated communication cost value is equal to or higher than the upper predetermined rank compared with the communication cost value registered in the communicable terminal data table D (YES in S11), the communication processing unit 131 In the table processing unit 132, as a communication route, the terminal ID in the terminal 10 that is the transmission source of the SQ notification packet, the communication quality between the terminal 10 and the terminal 10 corresponding to the terminal ID, the communication cost value, and the communication cost value Acquisition time (communication cost value registration time) is registered in the communicable terminal data table D. Then, the communication processing unit 131 causes the table processing unit 132 to delete the data related to the terminal 10 having the largest communication cost value in the registered communicable terminal data table D, thereby registering the registered content of the communicable terminal data table D. Is changed (S13).

  Step S11 is executed only when it is determined that the calculated communication cost value is equal to or higher than the upper predetermined rank as compared with the communication cost value registered in the communicable terminal data table D. Thus, since the communicable terminal data table D is updated, the amount of data stored in the storage unit 110 can be reduced.

  Then, the communication processing unit 131 notifies the table processing unit 132 of a route determination packet transmission command, and receives the command to determine the route determination packet including the terminal IDs of the terminal 10 and the H packet transmission source terminal 10. Is transmitted to the upper terminal 10 (S14). Thereafter, the communication processing unit 131 returns the process to step S1. Note that the order of processing in steps S13 and S14 may be reversed.

  FIG. 7 is a diagram showing an example of a communication sequence for establishing a communication route between terminals 10 in the PLC network shown in FIG. In this example, for convenience of explanation, in the PLC network 1, only the parent terminal 10a and the child terminals 10b-1 to 10b-4 are connected to the power line L.

  First, the parent terminal 10a performs steps S1 and S2 of FIG. 5 to transmit H packets to each child terminal 10b by broadcast (# 1). In step S2, since the parent terminal 10a is addressed to itself, the parent terminal 10a generates an H packet with the communication cost value set to 0 and the hop count set to 0.

  Here, it is assumed that only the child terminal 10b-1 among the child terminals 10b can receive the H packet from the parent terminal 10a. The child terminal 10b-1 can acquire the SQ from the parent terminal 10a to the child terminal 10b-1 by receiving the H packet from the parent terminal 10a.

  The child terminal 10b-1 executes Step S1, Step S3, Step S6 and Step S7 of FIG. 5 to transmit a response packet to the received H packet to the parent terminal 10a by unicast (# 2). . The parent terminal 10a receives the response packet from the child terminal 10b-1, and executes step S1, step S3, and step S4 in FIG. 5 to transfer the child terminal 10b-1 acquired from the response packet to the parent terminal 10a. In order to notify the SQ, an SQ notification packet is transmitted to the child terminal 10b-1 (# 3).

  The child terminal 10b-1 executes step S8 and step S9 to receive the SQ notification packet and acquire the SQ notified by the received SQ notification packet. Accordingly, the child terminal 10b-1 can acquire the SQ between the parent terminal 10a and the own device in both directions.

  Thus, for the terminal 10S on the transmission side of the H packet, the H packet is a communication packet for notifying the terminal 10 in the PLC network 1 of the existence of the own terminal 10S, and is transmitted to the PLC network 1 at a predetermined time interval. Automatically sent. Then, for the terminal 10R on the receiving side of the H packet, the H packet is used by the terminal 10R on the receiving side of the H packet to acquire the SQ from the terminal 10S on the transmitting side of the H packet to the terminal 10R on the receiving side. Communication packet.

  For the terminal 10R on the H packet receiving side, the response packet is created when the terminal 10S on the H packet transmitting side is the route construction terminal 10, and is returned to the terminal 10S on the transmitting side of the H packet. It is. Then, for the terminal 10S on the H packet transmitting side, the response packet is acquired by the terminal 10S on the H packet transmitting side from the terminal 10R on the H packet receiving side to the terminal 10S on the transmitting side of the H packet. It is a communication packet used for this purpose.

  Further, for the terminal 10R on the H packet receiving side, the SQ notification packet is a communication packet for receiving an SQ notification from the terminal 10R on the H packet receiving side to the terminal 10S on the H packet transmitting side.

  Accordingly, the terminal 10R on the receiving side of the H packet acquires the SQ from the terminal 10S on the transmitting side of the H packet to the own terminal 10R by receiving the H packet, and transmits and receives the response packet and the SQ notification packet. The SQ from the terminal 10R to the terminal 10S on the H packet transmission side can be acquired, and the SQ can be acquired bidirectionally with the terminal 10S on the H packet transmission side.

  Returning to FIG. 5, the child terminal 10 b-1 executes the step S 10, thereby calculating the communication cost value based on the SQ having the larger value, that is, the communication quality having the lower communication quality. By executing step S11, it is determined whether the calculated communication cost value is equal to or higher than the upper predetermined rank. Here, it is assumed that the calculated communication cost value is equal to or higher than the upper predetermined rank as compared with the communication cost value included in the communicable terminal data table D. The child terminal 10b-1 executes step S13, updates the communicable terminal data table D, executes step S14, and transmits a route determination packet to the parent terminal 10a (# 4).

  Next, when the transmission time of the H packet arrives, the child terminal 10b-1 executes steps S1 and S2 of FIG. 5 and transmits the H packet to the other terminals 10 by broadcast (# 5). . In step S2, the child terminal 10b-1 obtains a communication cost value based on the bidirectional SQ and the number of hops with the parent terminal 10a acquired due to reception of the H packet from the parent terminal 10a. , H packets are generated.

  Here, it is assumed that the parent terminal 10a and the child terminal 10b-2 can receive the H packet, and the child terminal 10b-3 and the child terminal 10b-4 cannot receive the H packet.

  The child terminal 10b-2 executes steps S1, S3, and S6 of FIG. 5. Since the child terminal 10b-1 is a communication route construction terminal, the child terminal 10b-2 executes step S7 and transmits a response packet (# 6). The child terminal 10b-1 transmits an SQ notification packet in the same manner as the transmission of the SQ notification packet (# 3) (# 7), and the child terminal 10b-2 is similar to the transmission of the route determination packet (# 4). Then, the route determination packet is transmitted to the child terminal 10b-1 (# 8).

  The child terminal 10b-1 receives the route determination packet, executes step S1 and step S5 in FIG. 5, and adds the terminal ID of the upper terminal (here, the terminal ID of the parent terminal 10a) to the received route determination packet. And is transmitted to the parent terminal 10a (# 9). When the parent terminal 10a receives the route determination packet from the child terminal 10b-1, the parent terminal 10a executes steps S1 and S5 in FIG. 5 and passes through the child terminal 10b-1, and the parent terminal 10a and the child terminal 10b- 2 can be grasped.

  Thus, the route determination packet is a communication packet that is created and transmitted for the first time in the PLC network 1 when the child terminal 10b updates the communicable terminal data table D, and the communication route from the child terminal 10b to the parent terminal 10a. Is a communication packet to notify the parent terminal 10a. In the route determination packet, the child terminal 10b that has received the route determination packet adds the terminal ID of the upper terminal 10 and transmits it to the upper terminal 10, whereby the communication route from the child terminal 10b to the parent terminal 10a is changed in the order in which the terminal IDs are arranged. And finally reach the parent terminal 10a.

  Next, when the H packet transmission time arrives, child terminal 10b-3 executes steps S1 and S2 of FIG. 5 and transmits H packets to other terminals 10 by broadcast (# 10). Here, it is assumed that only the child terminal 10b-2 has received the H packet. However, the child terminal 10b-2 executes Step S1, Step S3, and Step S6 of FIG. 5, and since the child terminal 10b-3 is not a communication route construction terminal, Step S7 is not executed and a response packet is not transmitted.

  With the configuration described above, in the PLC network 1 according to the first embodiment of the present invention, each terminal 10 transmits to each terminal 10 at predetermined time intervals using the H packet. Since the SQ is acquired, traffic in the PLC network 1 can be reduced. Therefore, the slave terminal 10b only needs to store the SQ with the adjacent terminal 10 that is relayed on the storage unit 110 via the communication route in which the SQ with the parent terminal 10a is higher than the upper predetermined rank. Even in the PLC network 1, the traffic in the PLC network 1 can be reduced, the communication speed between the terminals 10 is relatively small, and the memory capacity of each terminal 10 is relatively small. Therefore, it is possible to satisfactorily establish a communication route between the terminals 10 in response to changes in the network topology in the PLC network 1. Thereby, communication between the terminals 10 can be performed satisfactorily.

  Further, in the present embodiment, in the PLC network 1, only when the terminal 10 that is the H packet transmission source is the terminal 10 for which the communication route with the parent terminal 10 a is established, The communication processing unit 131 executes processing for acquiring bidirectional communication quality with the terminal 10, and the terminal 10 that is the source of the H packet is not the terminal 10 for which the communication route with the parent terminal 10a is established. In this case, the process for acquiring the bidirectional communication quality between the terminal 10 that is the source of the H packet and the terminal 10 is not executed. As a result, the child terminals 10b that have not established a communication route with the parent terminal 10a communicate with each other to establish a communication route, thereby increasing traffic in the PLC network 1 unnecessarily. Can be prevented.

Next, another embodiment will be described.
(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 3, 8, 9, and 10. FIG. In the first embodiment, the child terminal 10b does not transmit a response packet to the H packet from the child terminal 10b that has not established a communication route with the parent terminal 10a. In the second embodiment, The child terminal 10b in which the communication route with the parent terminal 10a is not constructed transmits a response packet, but the child terminal 10b in which the communication route with the parent terminal 10a is not constructed does not transmit the H packet.

  Therefore, in the second embodiment, as indicated by a broken line in FIG. 3, the terminal 10 further includes an HP transmission enable flag storage unit 112 in the storage unit 110 in addition to the configuration in the first embodiment. A flag presence / absence determination unit 134 is further provided functionally in the control unit 130. The HP transmittable flag storage unit 112 is an area for storing a flag (HP transmittable flag) for identifying whether an H packet can be transmitted. The flag presence / absence determination unit 134 refers to the HP transmission enable flag storage unit 112 to identify whether the HP transmission enable flag is turned on.

  8 and 9 are flowcharts (part 1 and part 2) illustrating an example of the communication route construction process of the terminal 10 according to the second exemplary embodiment of the present invention. This process is different from the flowchart shown in FIG. 5 in that the communication processing unit 131 does not execute step S6 and executes steps S21 to S26. The same processing is executed for the existing steps. Hereinafter, the different steps will be described.

  This process is also executed when the terminal 10 is turned on. First, in step S21, the communication processing unit 131 determines whether the terminal 10 is the parent terminal 10a. If it is not determined that the terminal 10 is the parent terminal 10a (NO in S21), the communication processing unit 131 turns off the HP transmission enable flag (S22). If it is determined that the terminal 10 is the parent terminal 10a (YES in S21), the communication processing unit 131 turns on the HP transmittable flag (S26) and executes step S1.

  In step S1, when the H packet transmission timer unit 133 times the arrival of the H packet transmission time and receives the notification, the communication processing unit 131 executes step S23. In step S23, the communication processing unit 131 determines whether the HP transmission enable flag is on. Whether the HP transmission enable flag is on is determined when the communication processing unit 131 is notified of the HP transmission enable flag by the flag presence / absence determination unit 134. If it is not determined that the HP transmittable flag is on (NO in S23), the process returns to step S1, and if it is determined that the HP transmittable flag is on (YES in S23), The communication processing unit 131 creates an H packet, transmits the created H packet to each terminal 10 by broadcasting, and then returns the process to step 1 (S2). Here, the H packet to be transmitted is the same as that described above in the first embodiment.

  In step S1, it is determined that a communication packet has been received, and after executing steps S3 to S10, the communication processing unit 131 executes step S24. In step S24, the communication processing unit 131 causes the table processing unit 132 to determine whether or not the communication cost value calculated in step S10 is the first communication cost value registered in the communicable terminal data table D. The determination of the first communication cost value is made when the communication cost value is registered in the communicable terminal data table D. When determining that it is the first communication cost value (YES in S24), the communication processing unit 131 is notified by the table processing unit 132 of an instruction to turn on the HP transmission enable flag, The transmission enable flag is turned on (S25). Thereafter, the communication processing unit 131 executes step S13, causes the table processing unit 132 to register predetermined information such as the calculated communication cost value in the communicable terminal data table D, and a communication route is constructed.

  When it is not determined that the calculated communication cost value is the first communication cost value (NO in S24), the communication processing unit 131 executes steps S11, S13, and S14, and returns this process to step S1.

  FIG. 10 is a diagram illustrating an example of a communication sequence for establishing a communication route between the terminals 10 in the present embodiment. Since the parent terminal 10a executes steps S21 and S26 and is the parent terminal 10a, the HP transmission enable flag is turned on, and the steps S1, S23, and S2 of FIG. 8 are performed according to the arrival of the HP transmission time. Then, the H packet is broadcast and transmitted to the child terminal 10b (# 21). In this example, it is assumed that only the child terminal 10b-1 has received the H packet transmitted by the parent terminal 10a. Here, each terminal 10 is in a state in which the transmittable flag is turned off by executing step S21 and step S22 of FIG.

  Similar to the communication sequence shown in FIG. 7, child terminal 10b-1 transmits a response packet to the received H packet by unicast to parent terminal 10a (# 2). The packet is transmitted to the child terminal 10b-1 (# 3).

  When the child terminal 10b-1 receives the SQ notification packet, it executes step S8 and step S9 in FIG. 9 to receive the SQ notification packet and acquire the SQ notified by the received SQ notification packet. The child terminal 10b-1 calculates a communication cost value by executing Step S10, and determines whether the calculated communication cost value is equal to or higher than the upper predetermined rank by executing Step S11.

  The child terminal 10b-1 determines whether or not a communication cost value is registered in the communicable terminal data table D by executing step S24 of FIG. Here, since the communication cost value is not registered and the communication cost value calculated in step S10 is registered for the first time in the communicable terminal data table D, the child terminal 10b-1 executes step S25. Then, the HP transmission enable flag is turned on. Then, the child terminal 10b-1 transmits a route determination packet to the parent terminal 10a in the same manner as the communication sequence shown in FIG. 7 (# 4).

  After transmission of the route determination packet (# 4), the child terminal 10 whose HP transmission enable flag is turned on, that is, the child terminal 10b that can transmit the H packet is only the child terminal 10b-1. The child terminal 10b-1 performs step S1, step S23, and step S2 of FIG. 8 when the H packet transmission time arrives, thereby transmitting the H packet by broadcast to the other terminal 10 (# 22). Here, it is assumed that only the child terminal 10b-2 has received the H packet from the child terminal 10b-1. The transmission of the response packet (# 6) and the transmission of the SQ notification packet (# 7) are the same as the communication sequence shown in FIG.

  When the child terminal 10b-2 receives the SQ notification packet from the child terminal 10b-1, the child terminal 10b-2 executes Steps S8, S9, and S10 of FIG. 9 to calculate a communication cost value. Since the calculated communication cost value is the first communication cost value registered in the communicable terminal data table D, the child terminal 10b-3 executes steps S24 and S25 of FIG. 9 and turns on the HP transmission enable flag. To do. Thereafter, in the same manner as the communication sequence shown in FIG. 7, the communicable terminal data table D is updated and the route determination packet is transmitted (# 8, # 9).

  Thereby, in addition to the child terminal 10b-1, the child terminal 10b-2 also establishes a communication route with the parent terminal 10a, and the HP transmission enable flag is turned on. Therefore, the child terminal 10b-2 can execute step S1, step S23 and step S2 of FIG. 8 and transmit the H packet by broadcast to the other terminal 10 when the transmission available time arrives (# 23). On the other hand, the child terminal 10b-3 and the child terminal 10b-4 have not yet established a communication route with the parent terminal 10a, and the HP transmission enable flag remains in the off state. By executing S23, the H packet cannot be transmitted.

  With the above configuration, in this embodiment, while adopting a master-slave network, traffic in the PLC network 1 can be reduced, the communication speed between the terminals 10 is relatively small, and the memory of each terminal 10 is Even in the PLC network 1 having a relatively small capacity, the communication topology between the terminals 10 can be satisfactorily constructed corresponding to the change in the network topology in the PLC 1, as in the first embodiment. Has an effect.

  In the present embodiment, in the PLC network 1, only when the terminal 10 is the terminal 10 for which a communication route with the parent terminal 10 a is established, the H packet is broadcast to each terminal 10. Is not the terminal 10 for which the communication route with the parent terminal 10a is established, the H packet is not transmitted to each terminal 10 by broadcast. As a result, in this embodiment as well, as in the first embodiment, the child terminals 10b that do not have a communication route with the parent terminal 10a communicate with each other to establish a communication route. It is possible to effectively prevent the traffic in the PLC network 1 from being increased unnecessarily.

Next, another embodiment will be described.
(Third embodiment)
The third embodiment of the present invention will be described below with reference to FIGS. 3, 11, 12, and 13. FIG. In the first and second embodiments, a communication cost value of a predetermined rank or higher is registered in the communicable terminal data table, and each terminal 10 continues to search for a communication route of a communication cost value of a higher predetermined rank or higher. The terminal 10 according to the embodiment differs in that the search for the communication route is terminated when a communication cost value equal to or higher than a predetermined level capable of satisfactorily communicating with the parent terminal 10a is obtained.

  For this reason, as indicated by a broken line in FIG. 3, the terminal 10 includes an HP receivable flag storage unit 113 in the storage unit 110 in addition to the configurations in the first and second embodiments. The HP receivable flag storage unit 113 is an area for storing a flag (HP receivable flag) for identifying that an H packet can be received. The flag presence / absence determining unit 134 refers to the HP receivable flag storage unit 113 to identify whether the HP receivable flag is turned on.

Only when the receivable flag is turned on, the communication processing unit 131 performs a process for obtaining bidirectional communication quality between the H packet transmission source terminal 10 and the own terminal 10 and the receivable flag is turned off. If you have prohibits execution of the processing for acquiring the two-way communication quality between the own terminal 10 and the H packet source terminal 10.

  FIGS. 11 and 12 are flowcharts (part 1 and part 2) illustrating an example of the communication route construction process of the terminal 10 according to the third exemplary embodiment of the present invention. This process is also executed when the terminal 10 is turned on. The flowcharts of FIGS. 11 and 12 are different from the flowcharts shown in FIGS. 8 and 9 in that the processes of steps S31 to S34 are further executed. Processing with the same content is executed. Only different steps will be described below.

  After execution of step S22 or step S26, in this embodiment, the communication processing unit 131 turns on the HP receivable flag (S31). Thereafter, the communication processing unit 131 executes Step S1 as in the second embodiment. Steps S1 to S5 and step S23 are the same as those in the above-described second embodiment, and thus description thereof is omitted.

  In this embodiment, when it is determined in step S3 that the received communication packet is an H packet, the communication processing unit 131 determines whether the HP receivable flag is on (S32). The determination that the HP receivable flag is on is made when the flag presence / absence determining unit 134 notifies that the HP receivable flag is on. If it is not determined that the HP receivable flag is on (NO in S32), the communication processing unit 131 returns the process to step S1. If it is determined that the HP receivable flag is on (YES in S32), the communication processing unit 131 executes Step S7 and transmits a response packet. Since the processing content of subsequent step S8-step S14 and step S24 and S25 is the same as that of 2nd Embodiment, description is abbreviate | omitted.

  After execution of step S14, in the present embodiment, the communication processing unit 131 determines whether or not the communication cost value calculated in step S10 indicates a communication state with the parent terminal 10a having a predetermined level or higher (S33). ). If it is not determined that the communication cost value indicates a communication state with a predetermined level or higher (NO in S33), the communication processing unit 131 returns this processing to step S1, and communication with a communication cost value equal to or higher than the predetermined level. If it is determined that the status is indicated (YES in S33), the communication processing unit 131 turns off the HP receivable flag and returns this process to step S1.

  In this process, steps S31 to S34 are executed in the route determination process in the second embodiment shown in FIGS. 11 and 12, but the present invention is not limited to this, and the route construction process shown in FIG. Steps S31 to S34 may be executed. In this case, step S31 is executed before step S1, step S32 is executed after step S3 or step S6 is executed, and after it is determined YES in step S11, the process returns to step S1. Until then, step S33 and step S34 are executed.

  FIG. 13 is a diagram illustrating an example of a communication sequence for constructing a communication route between the terminals 10 in the present embodiment. Parent terminal 10a transmits an H packet (# 21) in the same manner as the communication sequence shown in FIG. When the parent terminal 10a transmits the H packet, the child terminals 10b-1 to 10b-4 execute step S31 of FIG. 11 and the HP receivable flag is turned on. In this example, similarly to the example described in the second embodiment, only the child terminal 10b-1 can receive the H packet.

  The child terminal 10b-1 that has received the H packet executes step S1, step S3, and step S32 of FIG. 11 to determine whether the HP receivable flag is on. Here, since the HP receivable flag is turned on, child terminal 10b-1 executes step S7 and transmits a response packet to parent terminal 10a by unicast (# 31).

  Thereafter, similar to the communication sequence shown in FIG. 10, the transmission of the SQ notification packet (# 3) and the transmission of the route determination packet (# 4) are performed.

  After transmitting the route determination packet, the child terminal 10b-1 executes Step S33 and determines whether or not the calculated communication cost value is equal to or higher than a predetermined level. In this example, it is assumed that the communication cost with the parent terminal 10a is equal to or higher than a predetermined level. Therefore, the child terminal 10b-1 executes step S34 to turn off the HP receivable flag.

  Thereafter, in this example, similar to the communication sequence shown in FIG. 10, the parent terminal 10a transmits an H packet to the child terminal 10b by broadcast when the HP transmission time arrives (# 22). In this example, it is assumed that only the child terminal 10b-1 has received the H packet even at this time. The child terminal 10b-1 executes Step S1, Step S3, and Step S32 of FIG. Here, since the HP receivable flag is turned off, the child terminal 10b-1 prohibits the response packet transmission processing in step S7 and does not transmit the response packet.

  With the above configuration, in this embodiment, in addition to the effects of the first embodiment, the child terminal 10b in which the communication route with the communication cost with the parent terminal 10a being equal to or higher than the predetermined level has received the H packet. Even in this case, since transmission of the response packet is prohibited, it is possible to secure a communication route capable of performing communication with the parent terminal 10a with communication quality of a predetermined level or higher, and thereafter, by not transmitting the response packet, Traffic in the PLC network 1 can be reduced.

Next, another embodiment will be described.
(Fourth embodiment)
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIGS. 3, 6, 14, 15, and 16. In the first to third embodiments, the terminal 10 that has received the response packet transmits the SQ notification packet by unicast to the terminal 10 that is the source of the response packet. In the fourth embodiment, the terminal 10 The SQ notification to be transmitted to the packet transmission source terminal 10 is accumulated (stored) in the storage unit 110 without being transmitted for a predetermined time, and after the predetermined time has elapsed, the response to the transmission source terminal 10 of each response packet is broadcast. To send.

  Therefore, as indicated by a broken line in FIG. 3, in the fourth embodiment, the terminal 10 adds the SQ notification transmission destination address storage unit 114 and the SQ notification information in addition to the configurations in the first to third embodiments. The storage unit 115 is functionally provided in the storage unit 110, and the SQ notification transmission timer unit 135 is functionally provided in the control unit 130.

  The SQ notification transmission destination address storage unit 114 is an area in which the terminal ID of the terminal 10 that has transmitted the response packet is registered each time a response packet is received from the other terminal 10. The SQ notification information storage unit 115 is an area for storing information included in the SQ notification packet for the terminal 10 identified by the terminal ID in association with the terminal ID registered in the SQ notification transmission destination address storage unit 114. is there. The information included in the SQ notification packet is, for example, data representing the SQ from the response packet transmission source terminal 10 to the terminal 10 obtained from the response packet, the sequence number of the received response packet, or the like.

  The SQ notification transmission timer unit 135 counts the elapse of a predetermined time from when the response packet is received, and notifies the communication processing unit 131 of the transmission time of the SQ notification.

  The communication processing unit 131 receives the notification of the transmission time of the SQ notification and transmits the SQ notification packet to the other terminal 10 by broadcasting. The communication processing unit 131 causes the table processing unit 132 to calculate a communication cost value when receiving the SQ notification packet transmitted to the own terminal 10.

  14 and 15 are flowcharts (part 1 and part 2) illustrating an example of the communication route construction process of the terminal 10 according to the fourth exemplary embodiment of the present invention. Compared with the flowcharts shown in FIGS. 11 and 12, the communication processing unit 131 executes steps S41 and S46 instead of steps S1 and S10, respectively, and the flowcharts of FIGS. Execution of S45 is different, and processing with the same contents is executed for those given the same reference numerals. Only the steps that differ will be described below.

  After executing step S31, the communication processing unit 131 executes step S41. In step S41, the communication processing unit 131 executes step S23 when the H packet transmission time arrives, executes step 3 when the communication packet is received, and the transmission timing of the SQ notification packet has arrived. In addition, step S42 described later is executed. The arrival of the transmission timing of the SQ notification packet is notified from the SQ notification timer unit 135.

  In step S42, the communication processing unit 131 determines whether it is necessary to transmit the SQ notification packet. Here, when the terminal ID is stored in the SQ notification transmission destination address storage unit 114, it is determined that the SQ packet needs to be transmitted. If it is not determined that the SQ notification packet needs to be transmitted (NO in S42), the communication processing unit 131 returns this processing to step S41, and determines that the SQ notification packet needs to be transmitted (S42). YES), the communication processing unit 131 refers to the SQ notification transmission destination address storage unit 114 and the SQ notification information storage unit 115 to create an SQ notification packet.

  The created SQ notification packet includes, for example, an operation code, a transmission source terminal ID (terminal ID of the own terminal 10), a sequence number, and a transmission destination terminal ID (see FIG. 6E). 1st terminal ID to n-th terminal ID) and data representing SQ corresponding to the terminal ID. The terminal ID of the transmission destination of the SQ notification packet is stored in the SQ notification transmission destination address storage unit 114, and the data indicating the sequence number and SQ is stored in the SQ notification information storage unit 115. It is included in the SQ notification packet.

  The communication processing unit 131 broadcasts the created SQ notification packet to each terminal 10 (S43). Thereafter, the communication processing unit 131 discards the data (data indicating the terminal ID, SQ, sequence number, etc.) registered in the SQ notification transmission destination address storage unit 114 and the SQ notification information storage unit 115, and proceeds to step S41. return.

  If it is determined in step S3 that the received packet is a response packet, the communication processing unit 131 executes step S44 described later. In step S44, the communication processing unit 131 notifies the response packet to the table processing unit 132, and returns the process to step S41. The communication processing unit 131 causes the table processing unit 132 to register the terminal ID of the terminal 10 that is the transmission source of the response packet in the SQ notification transmission destination address storage unit 114 based on the input response packet. Correspondingly, the data indicating the SQ from the terminal 10 that is the source of the response packet to the terminal 10 and the sequence number of the response packet are registered in the SQ notification information storage unit 115. Then, when registering the first terminal ID in the SQ notification transmission destination address storage unit 114, the communication processing unit 131 instructs the table processing unit 132 to start measuring the time of the SQ notification transmission timer unit 135. .

  If steps S32, S7, and S8 are executed and it is determined that the SQ notification packet has been received within a predetermined time (YES in S8), the communication processing unit 131 executes step S45. In step S <b> 45, the communication processing unit 131 determines whether the received SQ notification packet includes the terminal ID of the own terminal 10, that is, whether it is an SQ notification packet to the own terminal 10. If it is not determined that the packet is an SQ notification packet to the own terminal 10 (NO in S45), the communication processing unit 131 returns this process to step S8 and determines that the packet is an SQ notification packet to the own terminal 10. If so (YES in S45), step S9 is executed. When it is determined that the received SQ notification packet includes the same sequence number as the response packet transmitted in step S7 (YES in S9), the communication processing unit 131 executes step S46.

  In step S46, the communication processing unit 131 notifies the table processing unit 132 of the SQ notification packet, causes the table processing unit 132 to acquire the SQ, and causes the communication cost value to be calculated. The acquired SQ corresponds to the own terminal 10 among the data representing the SQ included in the SQ notification packet. The communication cost value is calculated in the same manner as step S10 in the first to third embodiments based on the acquired SQ. Thereafter, the communication processing unit 131 executes Step S24. About step S24, S25, step S11-S14, and step S33, S34, since the process of the content same as the flowchart in FIG. 12 is performed, description is abbreviate | omitted.

  In this process, step S45 is executed after step S8, but step S45 may be executed after step S9.

  In this process, steps S41 to S46 are executed in the route construction process in the second embodiment shown in FIGS. 11 and 12, but the present invention is not limited to this, and FIGS. Steps S41 to S46 may be executed in the route construction process shown in FIG. In this case, in the route construction process shown in FIGS. 5, 11, and 12, step S <b> 41 is executed instead of step S <b> 1, and in step S <b> 41, when the transmission time of the SQ notification packet has arrived, Step S43 is executed. And step S44 is performed instead of step S4, and step S45 is performed after execution of step S8 or step S9. Further, step S46 is executed instead of step S10.

  FIG. 16 is a diagram illustrating an example of a communication sequence for constructing a communication route between the terminals 10 in the present embodiment. Parent terminal 10a transmits the H packet in the same manner as the communication sequence shown in FIG. 13 (# 21). In this example, it is assumed that the child terminals 10b-1 to 10b-3 have received the H packet. The child terminals 10b-1 to 10b-3 transmit a response packet in the same manner as the communication sequence shown in FIG. 13 (# 2).

  Each time the parent terminal 10a receives a response packet from the child terminals 10b-1 to 10b-3, the parent terminal 10a executes Step S41, Step S3, and Step S44 of FIG. That is, when the parent terminal 10a receives the response packet from the child terminal 10b-1, the terminal ID of the child terminal 10b-1 is stored in the SQ notification transmission destination address storage unit 114 and acquired from the received response packet. The SQ from the child terminal 10b-1 to the parent terminal 10a, the sequence number of the received response packet, and the like are associated with the terminal ID of the SQ notification transmission destination address storage unit 114 and stored in the SQ notification information storage unit 115. When the parent terminal 10a receives the response packet from the child terminal 10b-2 and the child terminal 10b-3, the SQ notification transmission destination address storage unit 114 also receives the response packet from the child terminal 10b-1. In addition, the terminal IDs of the child terminals 10b-2 and 10b-3 are stored, and the SQ obtained from the received response packet, the sequence number of the received response packet, and the like are associated with the terminal IDs. The information is stored in the information storage unit 115.

  Further, when the parent terminal 10a first registers the terminal ID in the SQ notification transmission destination address storage unit 114, that is, in this example, when registering the terminal ID of the child terminal 10b-1, the SQ notification transmission timer unit The timing of 135 is started.

  When the SQ notification transmission timer unit 135 notifies the arrival of the transmission time of the SQ notification packet, the parent terminal 10a executes Step S41, Step S42, and Step S43 of FIG. That is, the parent terminal 10a determines whether or not the SQ notification packet needs to be transmitted with reference to the SQ notification transmission destination address storage unit 114. In this example, since the terminal IDs of the child terminals 10b-1 to 10b-3 are registered in the SQ notification transmission destination address storage unit 114, the parent terminal 10a determines that the SQ notification packet needs to be transmitted. To do. Then, the parent terminal 10a sends an SQ notification packet including the terminal IDs of the child terminals 10b-1 to 10b-3 and the corresponding SQ and sequence number registered in the SQ notification information storage unit 115. It is created and transmitted by broadcast to the child terminals 10b-1 to 10b-4 (# 41).

  In this example, it is assumed that the child terminals 10b-1 to 10b-3 have received the SQ notification packet from the parent terminal 10a. Also, the child terminal 10b-4 is assumed to be in a state where it can communicate with the parent terminal 10a at this time, and the SQ notification packet from the parent terminal 10a can be received.

  When receiving the SQ notification packet, the child terminal 10b-1 to child terminal 10b-3 execute Step S8, Step S45, and Step S9 in FIG. That is, the child terminals 10b-1 to 10b-3 determine that the SQ notification packet has been acquired within a predetermined time, determine that the child terminal 10b-1 to 10b-3 is an SQ notification packet to the own terminal 10, and Since the SQ notification packet includes the same sequence number, step S46 of FIG. 15 is executed. The child terminals 10b-1 to 10b-3 execute step S46 in FIG. 15 to obtain data representing the SQ corresponding to the terminal ID of the own terminal 10 included in the SQ notification packet, and store it in the storage unit 110. The temporarily stored data representing the SQ from the parent terminal 10a to the terminal 10 is compared, and the communication cost value is calculated using the SQ having the larger value.

  Thereafter, the child terminals 10b-1 to 10b-3 execute step S24 in FIG. 15 to determine that the first communication cost value is registered in the communicable terminal data table D. Steps S13 and S14 are executed to transmit a route determination packet to the parent terminal 10a (# 42, # 43, # 44).

  In this embodiment, every time the terminal 10 receives a response packet, instead of transmitting the SQ notification packet by unicast, an SQ notification packet including SQs for a plurality of terminals 10 is broadcast at predetermined time intervals. Therefore, it is possible to effectively prevent a plurality of data from colliding in the PLC network 1.

Next, another embodiment will be described.
(Fifth embodiment)
A fifth embodiment of the present invention will be described with reference to FIGS. 3, 6, 17, 18, and 19. In the first to fourth embodiments, the terminal 10 transmits an SQ notification packet. In the fifth embodiment, the terminal 10 broadcasts an H packet including data representing the SQ from the terminal 10 that is the transmission source of the response packet to the terminal 10 together with the SQ notification to each terminal 10. Send with.

  For this reason, as indicated by a broken line in FIG. 3, the terminal 10 includes an SQ notification transmission destination address storage unit 114 and an SQ notification information storage unit 115 in addition to the configurations in the first to third embodiments. Functionally. The SQ notification transmission destination address storage unit 114 and the SQ notification information storage unit 115 are regions that perform the same functions as those in the above-described fourth embodiment, and thus description thereof is omitted.

  17 and 18 are flowcharts (part 1 and part 2) illustrating an example of the communication route construction process of the terminal 10 according to the fifth exemplary embodiment of the present invention. Compared with the flowcharts shown in FIGS. 11 and 12, in this process, step S54 is executed instead of step S3, step S56 is executed instead of step S8, and step S58 is executed instead of step S10. In addition, the processing of steps S51 to S53, S55 and S57 is different, and the processing having the same contents is executed for the steps having the same name and code. Hereinafter, the different steps will be described.

  If it is determined in step S23 that the HP transmission enable flag is on, in the present embodiment, the communication processing unit 131 executes step S51. In step S51, the communication processing unit 131 determines whether the terminal ID is registered in the SQ notification transmission destination address storage unit 114, that is, whether SQ notification is necessary. If it is not determined that the SQ notification is necessary (NO in S51), the communication processing unit 131 broadcasts a normal H packet to each terminal 10 (S52). On the other hand, when determining that the SQ notification is necessary (YES in S51), the communication processing unit 131 associates the terminal ID registered in the SQ notification transmission destination address storage unit 114 with the terminal ID. Then, an H packet with an SQ notification, which is an H packet including a sequence number (for SQ notification) registered in the SQ notification information storage unit 115 and data representing the SQ, is generated and transmitted to each terminal 10 by broadcast. (S53). Thereafter, the communication processing unit 131 returns the process to step S1.

  The H packet with SQ notification includes, for example, an operation code, a transmission source terminal ID (terminal ID of own terminal 10), a sequence number (for H packet), and a sequence number (for SQ notification, as shown in FIG. 6 (f). ), The terminal ID (first terminal ID to n-th terminal ID) of the transmission destination of the H packet with SQ notification, and data representing the SQ corresponding to the terminal ID. The terminal ID of the transmission destination of the H packet with SQ notification is stored in the SQ notification transmission destination address storage unit 114, but the sequence number (for SQ notification) and the data indicating the SQ are stored in the SQ notification information storage unit 115. What is stored is included in the H packet with SQ notification. The sequence number (for H packet) has the same content as the sequence number included in the H packet shown in FIG.

  Returning to FIG. 17, when the communication processing unit 131 determines that the communication packet is received in step S1, the communication processing unit 131 executes step S54. In step S54, the communication processing unit 131 identifies the received communication packet. If the communication packet is a route determination packet, the communication processing unit 131 executes step S5. If the communication packet is a normal H packet, step S54 is performed. If S32 is executed and the communication packet is a response packet, Step S55 described later is executed.

  In step S55, the communication processing unit 131 notifies the table processing unit 132 of the response packet received by the PLC interface unit 120. The communication processing unit 131 causes the table processing unit 132 to register the terminal ID of the response packet transmission source terminal 10 in the SQ notification transmission destination address storage unit 114 based on the response packet, and associate the terminal ID with the terminal ID. Thus, the data indicating the SQ from the terminal 10 that is the transmission source of the response packet to the terminal 10 and the sequence number of the response packet are registered in the SQ notification information storage unit 115. Thereafter, the communication processing unit 131 returns the process to step S1.

  After execution of steps S32 and S7, in the present embodiment, the communication processing unit 131 executes step S56. In step S56, the communication processing unit 131 determines whether or not the H packet with SQ notification has been received within a predetermined time. If it is not determined that the H packet with SQ notification has been received within the predetermined time (NO in S56), the communication processing unit 131 returns this processing to step S1, and has received the H packet with SQ notification within the predetermined time. (YES in S56), the communication processing unit 131 determines whether it is an SQ notification to the terminal 10 (S57). Here, when the terminal ID of the own terminal 10 is included in the H packet with SQ notification, it is determined that the SQ notification is to the own terminal 10.

  If it is not determined that the notification is an SQ notification to the terminal 10 (NO in S57), the communication processing unit 131 returns the process to step S56 and determines that the notification is an SQ notification to the terminal 10 (S57). If YES, the communication processing unit 131 executes Step S9. When it is determined in step S9 that the received H packet with SQ notification includes the same sequence number as the response packet transmitted in step S7 (YES in S9), the communication processing unit 131 executes step S58. .

  In step S58, the communication processing unit 131 notifies the table processing unit 132 of the H packet with SQ notification. The communication processing unit 131 causes the table processing unit 132 to acquire the SQ based on the data representing the SQ corresponding to the terminal 10 among the data representing the SQ included in the H packet with the SQ notification. The communication processing unit 131 causes the table processing unit 132 to calculate a communication cost value based on the acquired SQ, similarly to step S10 in the third embodiment. Thereafter, the communication processing unit 131 executes Step S24. About step S24, S25, step S11-S14, and step S33, S34, since the process of the same content as FIG. 17, FIG. 18 is performed, description is abbreviate | omitted.

  In this process, step S57 is executed after execution of step S56, but step S57 may be executed after execution of step S9.

  In this process, steps S51 to S58 are executed in the route construction process in the third embodiment shown in FIGS. 11 and 12, but the present invention is not limited to this, and FIGS. Steps S51 to S58 may be executed in the route construction process shown in FIG. In this case, in the route construction process shown in FIG. 5, when the arrival of the H packet transmission time is notified in step S1, step S51 is executed, and when it is determined NO in step S51, step S52 is executed. If it is executed and it is determined as YES in step S51, step S53 is executed. In the route construction process shown in FIGS. 8 and 9, after step S23 is executed, step S51 is executed. If NO is determined in step S51, step S52 is executed, and if YES is determined in step S51. Step S53 is executed.

  In the route construction process shown in FIGS. 5, 8, and 9, step S54 is executed instead of step S3, step S55 is executed instead of step S4, and step S56 is executed instead of step S8. Step S57 is executed after S9, and step S58 is executed instead of step S10.

  FIG. 19 is a diagram illustrating an example of a communication sequence for establishing a communication route between the terminals 10 in the present embodiment.

  When the parent terminal 10a is notified of the arrival of the transmission time of the H packet in step S1, step S23 and step S51 are executed, and the terminal ID is not registered in the SQ notification transmission destination address storage unit 114. Is executed, a normal H packet is created, and transmitted to each of the child terminals 10b-1 to 10b-4 by broadcast (# 51). In this example, the child terminals 10b-1 to 10b-3 transmit response packets in the same manner as the communication sequence shown in FIG. 16 (# 2).

  When the parent terminal 10a receives the response packet from the child terminals 10b-1 to 10b-3, the parent terminal 10a executes step S1, step S54, and step S55 to execute the response packet transmission source terminal 10, that is, the child terminal 10b-1 to 10b-1. The terminal ID of 10b-3 is registered in the SQ notification transmission destination address storage unit 114, the SQ from the child terminals 10b-1 to 10b-3 acquired from the response packet in association with the terminal ID to the parent terminal 10a. And the sequence number are registered in the SQ notification information storage unit 115.

  When it is determined in step S1 that the H packet transmission time has arrived, the parent terminal 10a executes steps S23 and S51, refers to the SQ notification transmission destination address storage unit 114, and needs to perform SQ notification. Determine if there is. Here, the terminal IDs of the child terminals 10b-1 to 10b-3 are registered in the SQ notification transmission destination address storage unit 114. Accordingly, the parent terminal 10a determines that SQ notification is necessary, executes step S53, and executes the terminal ID of the child terminals 10b-1 to 10b-3 and the SQ notification information storage unit associated with the terminal ID. An H packet with SQ notification including the SQ and sequence number registered in 115 is created and transmitted to each child terminal 10b by broadcast (# 52).

  In this example, it is assumed that the child terminals 10b-1 to 10b-3 have received the H packet with SQ notification from the parent terminal 10a. Also, the child terminal 10b-4 is assumed to be in a state where it can communicate with the parent terminal 10a at this time, and the H packet with the SQ notification from the parent terminal 10a can be received.

  When the slave terminal 10b-1 to the slave terminal 10b-3 receive the H packet with SQ notification, the slave terminal 10b-1 to the slave terminal 10b-3 execute Step S56, Step S57, and Step S9 of FIG. That is, each of the child terminals 10b-1 to 10b-3 determines that the H packet with SQ notification has been acquired within a predetermined time, determines that it is an SQ notification to the own terminal 10, and transmits the response packet transmitted by the own terminal 10. Step S58 in FIG. 18 is executed because the H packet with the SQ notification includes the same sequence number. The child terminals 10b-1 to 10b-3 execute step S58 in FIG. 18 to obtain data representing the SQ corresponding to the terminal ID of the own terminal 10 included in the SQ notification packet, and store it in the storage unit 110. The temporarily stored data representing the SQ from the parent terminal 10a to the terminal 10 is compared, and the communication cost value is calculated using the SQ having the larger value.

  Thereafter, the child terminals 10b-1 to 10b-3 execute step S24 in FIG. 18 to determine that the communication cost value is registered in the communicable terminal data table D for the first time. Steps S13 and S14 are executed to transmit a route determination packet to the parent terminal 10a (# 53 to # 55).

  With the above configuration, in the present embodiment, the SQ notification can also be used as the transmission of the H packet, so that the traffic amount in the PLC network 1 can be reduced as compared with the first to fourth embodiments.

Next, another embodiment will be described.
(Sixth embodiment)
A sixth embodiment of the present invention will be described with reference to FIGS. 3, 6, 20, 21, and 22. FIG. In the first to fifth embodiments, the route determination packet is transmitted to the destination terminal 10 of the SQ notification packet or the H packet with SQ notification by unicast, but in the sixth embodiment, the route determination packet is constructed. The communication route notification is included in the H packet and transmitted to each terminal 10 by broadcast.

  For this reason, as indicated by a broken line in FIG. 3, in this embodiment, the terminal 10 adds the route determination HP transmission flag storage unit 116 to the storage unit 110 in addition to the configurations of the first to fifth embodiments. Functionally prepared. The HP transmission flag storage unit with route determination 116 is an area for storing a flag (HP transmission flag with route determination) for identifying the generation and transmission of an H packet including data representing the constructed communication route. The flag presence / absence determination unit 134 refers to the route determination-added HP transmission flag storage unit 116 to identify whether the route determination-added HP transmission flag is turned on.

  When it is necessary to transmit a route determination notification when the transmission time of the H packet has arrived, the communication processing unit 131 needs to transmit an H packet with route determination to the upper terminal 10 and transmit the route determination notification. When there is no normal H packet as shown in FIG.

  20 and 21 are flowcharts (part 1 and part 2) illustrating an example of the communication route construction process of the terminal 10 according to the sixth exemplary embodiment of the present invention. Compared with the flowcharts shown in FIGS. 17 and 18, the communication processing unit 131 executes step S63 instead of step S54, and executes step S65 instead of step S5. Instead, the execution of step S64 is different from the execution of steps S61 and S62, and the same processing is executed for steps to which the same reference numerals and names are assigned. Hereinafter, the different steps will be described.

  If it is determined in step S23 that the transmission enable flag is on, it is determined whether or not SQ notification is necessary (S51), and if it is determined that SQ notification is necessary (YES in S51). The communication processing unit 131 creates an H packet with SQ notification and transmits it to each terminal 10 by broadcast (S53). If it is not determined that the SQ notification is necessary (NO in S51), the communication processing unit 131 determines whether the HP transmission flag with route determination is on (S61). Whether the HP transmission flag with route determination is turned on is determined when the flag presence determination unit 134 notifies that the HP transmission flag with route determination is turned on.

  If it is not determined that the route determination-added HP transmission flag is on (NO in S61), the communication processing unit 131 creates a normal H packet shown in FIG. Is transmitted by broadcast (S52), and then the process returns to step S31. If it is determined that the HP transmission flag is on (YES in S61), the communication processing unit 131 refers to the communicable terminal data table D, creates an H packet with route determination, and broadcasts each packet. It transmits to the terminal 10 (S62). Thereafter, the communication processing unit 131 turns off the HP transmission flag with route determination, and returns this process to step S1.

  The H packet with route determination is, for example, an H packet including data representing an operation code, a transmission source terminal ID, a sequence number, a communication cost value, and an upper terminal ID as shown in FIG. The upper terminal ID is the ID of the terminal 10 through which the terminal 10 communicates from the terminal 10 that is the transmission source of the H packet with route determination, similarly to the route determination packets of the first to fifth embodiments, When passing through a plurality of terminals 10, data representing terminal IDs of all terminals 10 is included. The upper terminal ID initially includes only the first upper terminal ID, but when passing through a plurality of terminals 10, terminal IDs subsequent to the second upper terminal ID are given when passing through the terminal 10. The

  When it is determined in step S1 that a communication packet has been received, in the present embodiment, the communication processing unit 131 executes step S63. In step S63, the communication processing unit 131 determines the type of the received communication packet. If the communication packet is a response packet, the communication processing unit 131 executes step S55. If the communication packet is a normal H packet, If S32 is executed and the communication packet is an H packet with route determination, step S65 described later is executed.

  Steps S32, S33, Steps S7, S9, S12, S13, Steps S24, S25 and Steps S56 to S58 are the same as those in the flowchart shown in FIG. In this embodiment, after execution of step S13, the communication processing unit 131 receives a command for notifying route determination from the table processing unit 132, and receives the command to turn on the HP transmission flag with route determination (S64). . After that, the communication processing unit 131 executes step S33, but since the content is the same as that of the fifth embodiment, description thereof is omitted.

  In step S65, when the terminal 10 is the parent terminal 10a, the communication processing unit 131 notifies the received H packet with route determination to the table processing unit 132, and notifies the table processing unit 132 with the H packet with route determination. Are associated with each other and registered in the communication route table. When the terminal 10 is the child terminal 10b, the communication processing unit 131 refers to the communicable terminal data table D and adds data representing the terminal ID of the next higher-level terminal 10 to the H packet with route determination. To the upper terminal. Thereafter, the communication processing unit 131 returns the process to step S1.

  In this process, steps S61 to S65 are executed in the route construction process in the fifth embodiment shown in FIGS. 17 and 18, but the present invention is not limited to this, and FIGS. 9, steps S61 to S65 may be executed in the route construction processing shown in FIGS. 11 and 12, 14 and 15. In this case, in the route construction process shown in FIG. 5, when the arrival of the H packet transmission time is notified in step S1, step S61 is executed, and when it is determined YES in step S61, step S62 is executed. If it is executed and NO is determined in step S61, step S52 is executed. In the route construction process shown in FIGS. 11, 12, 14, and 15, step S 61 is executed after step S 23, and step S 62 is executed when YES is determined in step S 61, and NO is determined in step S 61. If it is determined, step S52 is executed.

  Further, in the route construction processing shown in FIGS. 5, 8 and 9, 11, 12, 14 and 15, step S 63 is executed instead of step 3, and step S 65 is executed instead of step S 5. Step S64 is executed instead of S14.

  FIG. 22 is a diagram illustrating an example of a communication sequence for constructing a communication route between the terminals 10 in the present embodiment. When the H packet transmission time arrives, the parent terminal 10a executes steps S1, S23, S51, S61, and S52 of FIGS. 20 and 21 to broadcast ordinary H packets to each child terminal 10b. Then, it is transmitted (# 61). The child terminals 10b-1 to 10b-3 transmit a response packet to the parent terminal 10a in the same manner as the communication sequence shown in FIG. 19 (# 2).

  When the H packet transmission time arrives, the parent terminal 10a performs step S1, step S51, and step S53, thereby transmitting the H packet with SQ notification to each child terminal 10b by broadcasting (# 62). When the slave terminals 10b-1 to 10b-3 receive the H packet with SQ notification, they can communicate by executing Step S56, Step S57, Step S9, Step S58, Step S24, Step S25, Step S13, and Step S64. The terminal data table D is updated, and the HP transmission flag with route determination is turned on.

  In this example, it is assumed that the H packet transmission time of the child terminal 10b-1 comes next. When the H packet transmission time arrives, the child terminal 10b-1 executes steps S1, S23, S51, S61, and S62, refers to the communicable terminal data table D, and determines the H packet with route determination. Is transmitted to each terminal 10 by broadcast (# 63). Thereafter, the child terminals 10b-2 and 10b-3 also perform the same process according to the arrival of the HP transmission time, create an H packet with route determination, and transmit it to each terminal 10 by broadcast. Here, the description is omitted.

  With the above configuration, in the present embodiment, the terminal 10 transmits the communication route to the higher-level terminal 10 by unicast in order to include the H communication in the notification of the constructed communication route to the parent terminal 10a. Compared with the fifth embodiment, traffic in the PLC network 1 can be reduced.

Next, another embodiment will be described.
(Seventh embodiment)
In the seventh embodiment, in a communication network including a plurality of terminals connected to a predetermined communication network, a first terminal serving as a parent and a second terminal serving as a child among the plurality of terminals A method for constructing a communication route that is directly or relayed to another communication terminal, wherein the terminal communicates with another terminal via a communication network, a storage unit, the communication unit and the storage unit A control unit that controls the operation of the communication unit, wherein the communication unit of the plurality of terminals sends a notification communication packet that notifies communication quality between the own communication terminal and the first terminal at predetermined time intervals. A communication quality notification step for transmitting to other terminals by broadcast communication, and when the control unit of the second terminal receives the notification communication packet, To obtain bidirectional communication quality with the terminal itself A communication quality acquisition step for executing processing, and the control unit of the second terminal, based on the acquired bidirectional communication quality and the communication quality notified in the notification communication packet, The communication quality with the own terminal is calculated, and only when the calculated communication quality satisfies a predetermined condition, the communication route with the terminal that transmitted the notification communication packet and the calculated communication quality are stored in the storage unit. And a communication route construction step for transmitting the first terminal from a communication unit as a transmission target, and in the communication quality acquisition step, the communication unit of the second terminal transmits a source of the notification communication packet Based on the notification communication packet, the communication quality from the terminal that sent the notification communication packet to the own terminal is acquired as a process for acquiring the bidirectional communication quality between the terminal and the own terminal. In addition, a response packet that responds to the notification communication packet is transmitted to the terminal that is the transmission source of the notification communication packet, and the control unit of the terminal that is the transmission source of the notification communication packet transmits the response packet to the communication unit. If received, the communication quality from the second terminal that is the transmission source of the response packet to the own terminal is acquired from the response packet, and the acquired communication quality is the second transmission source of the response packet. The control unit of the second terminal that has been notified acquires the communication quality from the own terminal to the transmission source terminal of the notification communication packet based on the notification of the communication quality. The control unit of the second terminal is configured so that only when a communication route is established between the terminal that is the transmission source of the notification communication packet and the first terminal, the terminal that is the transmission source of the notification communication packet. Between own terminal When processing for obtaining bidirectional communication quality is performed, and the calculated communication quality is higher than the predetermined communication rank compared with the communication quality stored in the storage unit Only the communication route with the terminal that is the transmission source of the notification communication packet and the calculated communication quality are stored in the storage unit, and the first terminal is transmitted from the communication unit as a transmission target.

  Similarly to the first to sixth embodiments, the seventh embodiment uses the communication route construction method of the present invention for a PLC network, and the PLC network is, for example, as shown in FIG. And a plurality of terminals 10 (parent terminal 10a, child terminal 10b) connected by power lines L (L1, L2).

  The terminal 10 according to the seventh embodiment, like the terminal 10 according to the first embodiment shown in FIG. 3, is a setting means (not shown) for setting whether the terminal 10 is a parent terminal 10a or a child terminal 10b. A storage unit 110, a PLC interface unit 120 as an example of the communication unit, and a control unit 130 are provided. The storage unit 110 functionally includes a table storage unit 111, and the control unit 130 functionally includes a communication processing unit 131, a table processing unit 132, and an H packet transmission timer unit 133.

  The communication processing unit 131 according to the seventh embodiment operates as described with reference to FIG. 5 in that the communication processing unit 131 according to the first embodiment operates as described with reference to FIG. 23 below. Although different from 131, other points are the same as those of the communication processing unit 131 according to the first embodiment.

  FIG. 23 is a flowchart showing an example of a communication route construction process of the terminal according to the seventh embodiment of the present invention. This process is executed when, for example, the terminal 10 is turned on. First, similarly to step S1 of the first embodiment, the communication processing unit 131 determines whether or not the H packet transmission time has arrived and whether or not a communication packet has been received (S101).

  When the H packet transmission timer unit 133 notifies the arrival of the H packet transmission time and, as a result of this determination, if the H packet transmission time has arrived (H packet transmission time), the communication processing unit 131 As in step S2 of the first embodiment, the H packet shown in FIG. 6A is created as an example of the notification communication packet, and is transmitted to the PLC network 1 by broadcast communication, for example, by broadcast (S102). The process returns to step S101.

  On the other hand, if the result of determination in step S101 is that a communication packet has been received (packet reception), the communication processing unit 131 identifies the type of the received communication packet as in step S3 of the first embodiment ( S103).

  As a result of this identification, when the communication packet is a response packet (response packet), the communication processing unit 131 executes step S104. When the communication packet is a route determination packet (route determination packet), the communication processing unit 131 performs communication. The processing unit 131 executes step S105. When the communication packet is an H packet (H packet), the communication processing unit 131 executes step S106, and when the communication packet is an SQ notification packet ( For the (SQ notification packet), the communication processing unit 131 executes Step S108.

  In step S104, as in step S4 of the first embodiment, the communication processing unit 131 uses the table processing unit 132 to change from the terminal 10 at the response packet transmission source to the terminal based on the received signal strength of the response packet. 10 is obtained, and an SQ notification packet, which is a communication packet including data representing this SQ, is created. Then, the communication processing unit 131 transmits the created SQ notification packet by unicast to the terminal 10 that has transmitted the response packet, and then returns the process to step S101.

  In step S105, as in step S5 of the first embodiment, when the terminal 10 is the child terminal 10b, the communication processing unit 131 refers to the communicable terminal data table D and determines the received route. The terminal ID of the next higher-level terminal 10 is added to the packet and transmitted to the next higher-level terminal 10 by unicast. On the other hand, when the terminal 10 is the parent terminal 10a, the communication processing unit 131 uses the table processing unit 132 to set the transmission terminal ID and the upper terminal ID included in the route determination packet as the established communication route. The communication route table is updated by registering in the communication route table. Thereafter, the communication processing unit 131 returns the process to step S101.

  In step S106, as in step S6 of the first embodiment, the communication processing unit 131 refers to the communication cost value included in the received H packet, so that the terminal 10 that has transmitted the H packet becomes the route construction terminal. 10 is determined, and then the communication processing unit 131 determines whether the terminal 10 is not the parent terminal 10a. As a result of the determination, when the H packet transmission source terminal 10 is not the route construction terminal 10 or when the terminal 10 is not the parent terminal 10a (No), the communication processing unit 131 returns the process to step S101, When the terminal 10 is not the parent terminal 10a and the H packet transmission source terminal 10 is the route construction terminal 10 (Yes), the communication processing unit 131, as in step S7 of the first embodiment, A response packet having the same sequence number as the sequence number included in the H packet is created and transmitted to the H packet source terminal 10 (S107).

  Then, the communication processing unit 131 uses the table processing unit 132 to obtain the communication cost value and the hop number from the data representing the communication cost value and the hop number included in the received H packet. Further, the communication processing unit 131 uses the table processing unit 132 to acquire the SQ from the H packet transmission source terminal 10 to the terminal 10 based on the received signal strength of the received H packet, and temporarily stores it in the storage unit 110. Remember me.

  In this embodiment, the communication processing unit 131 executes step S107 only when the H packet transmission source terminal 10 is the route construction terminal 10 by executing step S106. It is possible to prevent unnecessary increase. Furthermore, only when the H packet transmission source terminal 10 is the route construction terminal 10, the communication processing unit 131 executes a process of acquiring a bidirectional SQ between the H packet transmission source terminal 10 and the own terminal 10. Therefore, an increase in traffic in the PCL network 1 can be suppressed.

  In step S108, as in step S8 of the first embodiment, the communication processing unit 131 determines whether or not an SQ notification packet has been received within a predetermined time after transmitting the response packet.

  As a result of this determination, when the SQ notification packet is not received within the predetermined time (No), the communication processing unit 131 returns this processing to step S101. On the other hand, if the result of this determination is that an SQ notification packet has been received within a predetermined time (Yes), the communication processing unit 131 determines that the received SQ notification packet is a step, as in step S9 of the first embodiment. It is determined whether the same sequence number as the response packet transmitted in S107 is included (S109).

  If the result of this determination is that the same sequence number is not included (No), the communication processing unit 131 returns this processing to step S101. On the other hand, as a result of this determination, if the same sequence number is included (Yes), the communication processing unit 131 uses the table processing unit 132 to convert the SQ notification packet into the SQ notification packet as in step S10 of the first embodiment. Based on this, a communication cost value is calculated (S110).

  The communication processing unit 131 uses the table processing unit 132 to compare the calculated communication cost value with the communication cost value registered in the communicable terminal data table D, similarly to step S11 of the first embodiment. Then, it is determined whether or not the rank is higher than a predetermined rank (S111).

  As a result of this determination, when the calculated communication cost value is not equal to or higher than the upper predetermined rank (No), the communication processing unit 131 determines the calculated communication cost value and the like as in step S12 of the first embodiment. The data temporarily stored in the storage unit 110 and used in the current communication route construction process is discarded (S112).

  On the other hand, as a result of this determination, if the calculated communication cost value is equal to or higher than the upper predetermined rank (Yes), the communication processing unit 131 uses the table processing unit 132 as in step S13 of the first embodiment. As a communication route, the terminal ID of the terminal 10 that is the source of the SQ notification packet, the communication quality between the terminal 10 and the terminal 10 corresponding to the terminal ID, the communication cost value, and the acquisition time of the communication cost value (communication Cost value registration time) is registered in the communicable terminal data table D. Then, using the table processing unit 132, the communication processing unit 131 uses the table processing unit 132 to register data relating to the terminal 10 having the highest communication cost value in the communicable terminal data table D, that is, data having a communication cost value less than the upper predetermined rank And the registered content of the communicable terminal data table D is changed (S113).

  Since step S <b> 111 is executed and step S <b> 113 is executed only when the calculated communication cost value is determined to be higher than the predetermined upper rank, the amount of data stored in the storage unit 110 can be reduced.

  Then, the communication processing unit 131 creates a route determination packet including the terminal IDs of the terminal 10 and the H packet transmission source terminal 10 using the table processing unit 132 as in step S14 of the first embodiment. To the upper terminal 10 (S14). Thereafter, the communication processing unit 131 returns the process to step S101.

  Since it operates as described above, in the seventh embodiment, since each terminal 10 obtains the SQ with the parent terminal 10a using the H packet, the traffic in the PLC network 1 can be reduced. . Therefore, the slave terminal 10b only needs to store the SQ with the adjacent terminal 10 that is relayed on the storage unit 110 via the communication route in which the SQ with the parent terminal 10a is higher than the upper predetermined rank. Even in the PLC network 1, the traffic in the PLC network 1 can be reduced, the communication speed between the terminals 10 is relatively small, and the memory capacity of each terminal 10 is relatively small. Therefore, it is possible to satisfactorily establish a communication route between the terminals 10 in response to changes in the network topology in the PLC network 1. Thereby, communication between the terminals 10 can be performed satisfactorily.

  Further, in the seventh embodiment, in the PLC network 1, the terminal 10 that is the source of the H packet is used only when the terminal 10 that is the source of the H packet is the terminal 10 for which the communication route with the parent terminal 10 a is established. The communication processing unit 131 executes processing for obtaining bidirectional communication quality between the terminal 10 and the own terminal 10, and the communication route between the terminal 10 that is the transmission source of the H packet and the parent terminal 10a is established. If it is not 10, the process for acquiring the bidirectional communication quality between the terminal 10 that is the transmission source of the H packet and the own terminal 10 is not executed. As a result, the child terminals 10b that have not established a communication route with the parent terminal 10a communicate with each other to establish a communication route, thereby increasing traffic in the PLC network 1 unnecessarily. Can be prevented.

  Here, in the above-described seventh embodiment, as in the second embodiment with respect to the first embodiment, the child terminal 10b that has not established a communication route with the parent terminal 10a transmits a response packet. , H packets may not be transmitted. That is, the child terminal 10b transmits the H packet as the notification communication packet only when the communication route between the own terminal 10 and the parent terminal 10a is established. In this case, as indicated by a broken line in FIG. 3, the terminal 10 further includes a HP transmission enable flag storage unit 112 in the storage unit 110 in addition to the configuration of the seventh embodiment, and the flag presence / absence determination unit 134. Is further provided functionally to the control unit 130.

  In the seventh embodiment described above, as in the third embodiment relative to the first and second embodiments, the terminal 10 can communicate with the parent terminal 10a well at a predetermined level or higher communication cost. The search for the communication route may be terminated when the value is obtained. That is, when the communication route between the parent terminal 10a and the own terminal 10b whose communication quality is equal to or higher than a predetermined level is stored in the storage unit 110, the child terminal 10b performs the above-described communication quality acquisition step. It is forbidden. In this case, as indicated by a broken line in FIG. 3, the terminal 10 functionally adds an HP transmission enable flag storage unit 112 and an HP reception enable flag storage unit 113 to the storage unit 110 in addition to the configuration of the seventh embodiment. In addition, a flag presence / absence determination unit 134 is further provided functionally in the control unit 130.

  Further, in the seventh embodiment described above, as in the fourth embodiment with respect to the first to third embodiments, the terminal 10 transmits the SQ notification to be transmitted to the terminal 10 that is the transmission source of the response packet. It may be configured to accumulate (store) in the storage unit 110 without transmitting for a predetermined time, and to transmit to the terminal 10 that is the source of each response packet by broadcast communication, for example, by broadcast after a predetermined time has elapsed. . That is, when receiving a response packet, the terminal 10 that has transmitted the H packet as an example of the notification communication packet stores the communication quality from the terminal 10 that has transmitted the response packet to the terminal 10 in the storage unit 110. A PLC interface as an example of a communication unit including an H packet including data indicating communication quality stored at a predetermined timing in association with a terminal ID that is an identifier for identifying the communication quality notification destination terminal 10 When the terminal 10 of the own terminal 10 includes the terminal ID of the own terminal 10, the terminal 10 that has transmitted the broadcast packet from the unit 120 to the other terminal 10 by broadcast communication and received the H packet includes the communication quality corresponding to the terminal ID of the own terminal 10 Is obtained. In this case, as indicated by a broken line in FIG. 3, the terminal 10 includes an HP transmission enable flag storage unit 112, an HP reception enable flag storage unit 113, and an SQ notification transmission destination address storage unit in addition to the configuration of the seventh embodiment. 114 and SQ notification information storage unit 115 are further functionally provided in storage unit 110, and flag presence / absence determination unit 134 and SQ notification transmission timer unit 135 are further functionally provided in control unit 130.

  In the seventh embodiment described above, as in the fifth embodiment with respect to the first to fourth embodiments, the terminal 10 also serves as an SQ notification from the terminal 10 that has transmitted the response packet to the own terminal. The H packet including data representing the SQ to 10 may be transmitted to each terminal 10 by broadcast communication, for example, by broadcast. That is, when receiving the response packet, the terminal 10 that has transmitted the H packet as an example of the notification communication packet stores the communication quality from the terminal 10 that has transmitted the response packet to the terminal 10 in the storage unit, Data indicating the stored communication quality is associated with a terminal ID that is an identifier for identifying the communication quality notification destination terminal 10 and included in an H packet (H packet with SQ notification) as an example of a communication unit. When the terminal 10 of the own terminal 10 is included, the terminal 10 that has transmitted the H packet from the PLC interface unit 120 of the terminal to the other terminal 10 by broadcast communication corresponds to the terminal ID of the own terminal. Data representing communication quality to be acquired is acquired. In this case, as indicated by a broken line in FIG. 3, the terminal 10 includes an HP transmission enable flag storage unit 112, an HP reception enable flag storage unit 113, and an SQ notification transmission destination address storage unit in addition to the configuration of the seventh embodiment. 114 and SQ notification information storage unit 115 are further functionally provided in storage unit 110, and flag presence / absence determination unit 134 and SQ notification transmission timer unit 135 are further functionally provided in control unit 130.

  Further, in the seventh embodiment described above, as in the sixth embodiment relative to the first to fifth embodiments, the terminal 10 includes the notification of the established communication route in the H packet and performs broadcast communication. For example, it may be configured to transmit to each terminal 10 by broadcast. That is, in the above-described communication route construction step, the terminal 10 includes a communication route and communication quality notification in an H packet (H packet with route determination) as an example of a notification communication packet, and transmits it to other terminals 10. Thus, the broadcast is transmitted from the PLC interface unit 120 as an example of the communication unit. In this case, as indicated by a broken line in FIG. 3, the terminal 10 includes an HP transmission enable flag storage unit 112, an HP reception enable flag storage unit 113, and an SQ notification transmission destination address storage in addition to the configuration of the seventh embodiment. Unit 114, SQ notification information storage unit 115, and HP transmission flag storage unit with route determination 116 are further functionally provided in storage unit 110, and flag presence / absence determination unit 134 and SQ notification transmission timer unit 135 are functionally provided in control unit 130. In addition.

Next, another embodiment will be described.
(Eighth embodiment)
The terminal 10 according to the first and seventh embodiments transmits a response packet when receiving an H packet from the route construction terminal 10, but the terminal 10 according to the eighth embodiment obtains a temporary communication cost value. A response packet is transmitted when the communication quality satisfies a predetermined standard. Here, the eighth embodiment will be described based on the seventh embodiment, but the first embodiment can be based on the same.

  For this reason, as shown in FIG. 3, the terminal 10 according to the eighth embodiment has setting means (not shown) for setting whether it is a parent terminal 10a or a child terminal 10b, a storage unit 110, and a PLC. An interface unit 120 and a control unit 130 are provided. The storage unit 110 functionally includes a table storage unit 111, and the control unit 130 functionally includes a communication processing unit 131, a table processing unit 132, and an H packet transmission timer unit 133.

  The communication processing unit 131 and the table processing unit 132 according to the eighth embodiment operate as described with reference to FIG. 23 in the seventh embodiment. The other points are the same as those of the communication processing unit 131 and the table processing unit 132 according to the seventh embodiment.

  FIG. 24 is a flowchart showing an example of a communication route construction process of the terminal according to the eighth embodiment of the present invention. Here, when the operation of the terminal 10 according to the eighth embodiment is the same as that of the terminal 10 according to the seventh embodiment, the same reference numerals as those in FIG. Omitted where appropriate.

  This process is executed when, for example, the terminal 10 is turned on. In FIG. 24, first, the communication processing unit 131 determines whether or not the H packet transmission time has arrived and whether or not a communication packet has been received (S101), as in the seventh embodiment. One of step S102 and step S103 is executed according to the above.

  In step S103, the communication processing unit 131 identifies the type of the received communication packet, as in step S103 of the seventh embodiment. As a result of this identification, the communication processing unit 131 executes step S104 when the communication packet is a response packet (response packet), and executes step S105 when the communication packet is a route determination packet (route determination packet). If the communication packet is an SQ notification packet (SQ notification packet), step S108 is executed. It should be noted that if the communication packet is an H packet (H packet), step S121 is executed. To do.

  After execution of step S108, the communication processing unit 131 executes step S109 to step S114 as in the seventh embodiment.

  In step S121, the communication processing unit 131 uses the table processing unit 132 to refer to the communicable terminal data table D to calculate the temporary communication cost value except for the terminal 10 whose communication cost value is 0, and this calculation is performed. It is determined whether or not the temporary communication cost value is equal to or less than a predetermined reference value. The predetermined reference value is determined according to the specifications in consideration of communication quality required for the PLC network 1, communication reliability, and the like. Here, in calculating the temporary communication cost value, the terminal 10 having a communication cost value of 0 is excluded because the communication route with the parent terminal 10a has not been established.

  As a result of the determination, if the calculated temporary communication cost value is not less than or equal to the predetermined reference value, the communication processing unit 131 returns the process to step S101, while the calculated temporary communication cost value is determined in advance. If it is equal to or smaller than the reference value, the communication processing unit 131 returns the process to step S101 after executing step S107.

  As described above, the table processing unit 132 calculates a temporary communication cost value in addition to the processing of the seventh embodiment, and the communication processing unit 131 adds the calculated temporary communication to the processing of the seventh embodiment. Processing for transmitting a response packet is also performed when the cost value is equal to or less than a predetermined reference value.

This temporary communication cost value is a temporary communication cost value used as a guideline for determining whether or not a response packet should be returned when an H packet is received, and the communication cost accommodated in the received H packet. Based on the value and the SQ obtained from the received signal strength of the received H packet, for example, it is calculated by Equation (2).
(Temporary communication cost value) = (Communication cost value in H packet) + Ka × (SQ due to reception of H packet) + Kb × 1 Expression (2)
Here, Ka and Kb are the same as in Equation (1), and the term Kb × 1 is due to the increase in the number of hops.

  Step S121 will be described more specifically. For example, when the communicable terminal data table D has the registration contents shown in FIG. 25, the table processing unit 132 sets the terminal ID = 1 and the terminal ID whose communication cost value is 0. The temporary communication cost value is calculated excluding the terminal 10 of = 31. Here, to simplify the description, assuming that Ka = 1 and Kb = 0, the temporary communication cost value of the terminal 10 with the terminal ID = 2 is calculated as 14 + 13 = 27, and the temporary communication cost value of the terminal 10 with the terminal ID = 5 is calculated. The communication cost value is calculated as 3 + 17 = 20, the temporary communication cost value of the terminal 10 with terminal ID = 8 is calculated as 7 + 9 = 16, and the temporary communication cost value of the terminal 10 with terminal ID = 15 is 12 + 13 = 25. Then, the temporary communication cost value of the terminal 10 with the terminal ID = 22 is calculated as 22 + 7 = 29.

  If the predetermined reference value is 20, for example, the temporary communication cost values of the terminal 10 with the terminal ID = 5 and the terminal 10 with the terminal ID = 8 are 20 or less, respectively. When the H packet is received from the terminal 10, the communication processing unit 131 returns a response packet by executing Step S121 and Step S107.

  The bidirectional SQ between the own terminal 10 and the adjacent terminal 10 adjacent thereto is the larger SQ of the SQ from the own terminal 10 to the adjacent terminal 10 and the SQ from the adjacent terminal 10 to the own terminal 10 That is, the communication quality is worse. For this reason, as can be seen by comparing the formula (1) and the formula (2), the communication cost value is equal to or greater than the temporary communication cost value. That is, the temporary communication cost value is the best value that the communication cost value can take when this true communication cost value is calculated. The case where the communication cost value is equal to the temporary communication cost value is the case where the SQ from the own terminal 10 to the adjacent terminal 10 is equal to the SQ from the adjacent terminal 10 to the own terminal 10. Therefore, by eliminating the communication route when the temporary communication cost value exceeds the predetermined reference value, the SQ from the own terminal 10 to the adjacent terminal 10 and the adjacent terminal 10 to the own terminal 10 regarding the communication route with poor communication quality. Traffic in the PLC network 1 can be reduced by omitting the process of searching for SQ bidirectional SQ.

Next, another embodiment will be described.
(Ninth embodiment)
The terminal 10 according to the eighth embodiment transmits a response packet when the temporary communication cost value is equal to or less than the reference value. However, the terminal 10 according to the ninth embodiment replaces this with a temporary communication cost value. Is a response packet when it is higher than a predetermined rank, for example, within the upper third rank.

  Since the terminal 10 according to the eighth embodiment transmits a response packet when the temporary communication cost value is equal to or less than the reference value, the response packet is transmitted even if the H packet is received depending on the reference value setting. However, there may be a case where a communication route is not constructed or a case where only one or two communication routes are constructed even though there are many adjacent terminals 10, but the provisional communication cost as in the ninth embodiment may occur. If it is configured to transmit a response packet when the value is higher than a predetermined rank, a communication route is always constructed.

  Here, the ninth embodiment will be described based on the seventh embodiment, but the first embodiment can be based on the same.

  For this reason, as shown in FIG. 3, the terminal 10 according to the ninth embodiment includes a setting unit (not shown) for setting whether the terminal 10a is a parent terminal 10a or a child terminal 10b, a storage unit 110, and a PLC. An interface unit 120 and a control unit 130 are provided. The storage unit 110 functionally includes a table storage unit 111, and the control unit 130 functionally includes a communication processing unit 131, a table processing unit 132, and an H packet transmission timer unit 133.

  The communication processing unit 131 and the table processing unit 132 according to the ninth embodiment operate as described with reference to FIG. 26, and the seventh embodiment operates as described with reference to FIG. 23. The other points are the same as those of the communication processing unit 131 and the table processing unit 132 according to the seventh embodiment.

  FIG. 26 is a flowchart showing an example of a communication route construction process of the terminal according to the ninth embodiment of the present invention. Here, when the operation of the terminal 10 according to the ninth embodiment is the same as that of the terminal 10 according to the seventh embodiment, the same reference numerals as those in FIG. Omitted as appropriate.

  This process is executed when, for example, the terminal 10 is turned on. In FIG. 26, first, the communication processing unit 131 determines whether or not the H packet transmission time has arrived and whether or not a communication packet has been received (S101), as in the seventh embodiment, and the result of the determination. One of step S102 and step S103 is executed according to the above.

  In step S103, the communication processing unit 131 identifies the type of the received communication packet, as in step S103 of the seventh embodiment. As a result of this identification, the communication processing unit 131 executes step S104 when the communication packet is a response packet (response packet), and executes step S105 when the communication packet is a route determination packet (route determination packet). If the communication packet is an SQ notification packet (SQ notification packet), step S108 is executed. It should be noted that if the communication packet is an H packet (H packet), step S131 is executed. To do.

  After execution of step S108, the communication processing unit 131 executes step S109 to step S114 as in the seventh embodiment.

  In step S131, the communication processing unit 131 refers to the communicable terminal data table D using the table processing unit 132, calculates the temporary communication cost value except for the terminal 10 whose communication cost value is 0, Judge whether or not it is higher than the rank. Here, the calculated temporary communication cost value being equal to or higher than the upper predetermined rank corresponds to the case where the acquired communication quality with the parent terminal 10a satisfies the predetermined condition.

  As a result of the determination, when the calculated temporary communication cost value is not higher than the upper predetermined rank (No), the communication processing unit 131 returns the process to step S101, while the calculated temporary communication cost value is higher. If it is equal to or higher than the predetermined rank (Yes), the communication processing unit 131 returns the process to step S101 after executing step S107.

  As described above, the table processing unit 132 calculates a temporary communication cost value in addition to the processing of the seventh embodiment, and the communication processing unit 131 adds the calculated temporary communication to the processing of the seventh embodiment. A process of transmitting a response packet is also performed when the cost value is higher than a predetermined rank.

  For example, in the case where the communicable terminal data table D has the registration contents shown in FIG. 25, the terminal IDs are 8, 5, 15, 2, and 22 in order of good communication quality. When the response packet is returned, when the H packet is received from any one of the terminals 10 with the terminal IDs = 8, 5, and 15, the communication processing unit 131 executes step S131 and step S107 to return the response packet. I will reply.

  By configuring the terminal 10 in this way, the traffic in the PLC network 1 is reduced by omitting the bidirectional SQ search process when an H packet is received from the terminal 10 that is not higher than the predetermined rank. be able to. In addition, since a bidirectional SQ is searched for at least with the terminal 10 having a higher rank than the predetermined rank, a communication route can be secured. In particular, after the communication route is established, the communication route value is calculated instead of the provisional communication cost value, and the communication route having the best communication quality is set as the main route and the other communication route is set as the backup route. When it occurs, the communication reliability is improved by quickly switching to the backup route. In the PLC network 1, the communication quality can change dynamically, and thus such a configuration is effective.

Next, another embodiment will be described.
(Tenth embodiment)
The terminal 10 according to the ninth embodiment transmits a response packet when the provisional communication cost value is equal to or higher than the upper predetermined rank. In addition, the terminal 10 according to the tenth embodiment A response packet is transmitted when the communication route is stable over time. Here, the tenth embodiment will be described based on the seventh embodiment, but the first embodiment can be based on the same.

  For this reason, the terminal 10 according to the tenth embodiment, as shown in FIG. 3, a setting means (not shown) for setting whether the terminal 10a is a parent terminal 10a or a child terminal 10b, a storage unit 110, and a PLC An interface unit 120 and a control unit 130 are provided. The storage unit 110 functionally includes a table storage unit 111, and the control unit 130 functionally includes a communication processing unit 131, a table processing unit 132, and an H packet transmission timer unit 133.

  FIG. 27 is a diagram illustrating an example of the communicable terminal data table D ′ according to the tenth embodiment of the present invention. When the terminal 10 is the child terminal 10b, the communicable terminal data table is stored in the table storage unit 111. The communicable terminal data table D ′ in the tenth embodiment includes the terminal ID, SQ, and communication cost. In addition to the value and the acquisition time, the number of received H packets within a predetermined time, and an effective link indicating whether the communication route with the adjacent terminal 10 is stable in time. Provide a flag. The valid link flag indicates that the communication route is temporally stable when it is 1, while it indicates that the communication route is not temporally stable when it is 0. .

  The communication processing unit 131 according to the tenth embodiment operates as described with reference to FIG. 23, and the communication processing unit according to the seventh embodiment operates as described with reference to FIG. Although it differs from 131, other points are the same as the communication processing unit 131 according to the seventh embodiment.

  The table processing unit 132 according to the tenth embodiment operates as described with reference to FIG. 23 in the seventh embodiment in that it operates as described with reference to FIGS. 28 and 29 below. The other points are the same as those of the table processing unit 132 according to the seventh embodiment.

  In the tenth embodiment, the table processing unit 132 also executes the next process that periodically initializes the number of received H packets to 0 in order to determine whether the communication route is temporally stable. is doing.

  FIG. 28 is a flowchart showing processing for initializing the number of received H packets. In FIG. 28, when it is time to initialize the number of received H packets, the table processing unit 132 executes initialization from the terminal 10 in the first record of the communicable terminal data table D ′, for example, First, it is determined whether or not the number of H packets received is greater than 0 (S151).

  As a result of this determination, if the number of received H packets is greater than 0 (Yes), the table processing unit 132 determines the number of received H packets in order to determine the temporal stability of the communication route at the next timing. Is initialized to 0 (S152), and the process returns to step S151 to execute initialization for the terminal 10 in the next record of the communicable terminal data table D ′.

  On the other hand, if the result of this determination is that the number of received H packets is 0 (No), the communication route is not temporally stable, so that the table processing unit 132 displays this with an effective link flag. Then, it is determined whether or not the valid link flag is 0 (S153). If the effective link flag is 0 as a result of this determination (Yes), the table processing unit 132 performs processing to execute initialization for the terminal 10 in the next record of the communicable terminal data table D ′. Returning to step S151, on the other hand, if the effective link flag is not 0 (No) as a result of this determination, the table processing unit 132 sets the effective link flag to indicate that the communication route is not temporally stable. The effective link flag is set to 0 (S154).

  Next, since the communication route is not temporally stable, the table processing unit 132 deletes the communication route that passes through the adjacent terminal 10 adjacent to the own terminal 10 (S155).

  Then, the table processing unit 132 determines whether or not initialization has been executed for all terminals 10, that is, for all records of the communicable terminal data table D ′ (S 156). As a result of this determination, when the initialization process has not been executed for all the terminals 10 (No), the table processing unit 132 initializes the terminals 10 in the next record of the communicable terminal data table D ′. If the result of this determination is that initialization processing has been executed for all terminals 10 (Yes), the processing ends and the number of H packets received Wait until the next timing to initialize.

  The initialization process for initializing the number of received H packets is periodically executed at a predetermined time interval. When the next timing for initializing the number of received H packets is reached, the table processing unit 132 sets the number of received H packets. Steps S151 to S156 for initializing the number of received packets are performed.

  By operating the table processing unit 132 in this way, the number of H packets received for each adjacent terminal 10 is initialized at a predetermined time interval, and a predetermined standard related to stability is set within a time interval. An unsatisfied communication route has the valid link flag set to 0, and the communication route is deleted.

  FIG. 29 is a flowchart showing an example of a communication route construction process of the terminal according to the tenth embodiment of the present invention. Here, when the operation of the terminal 10 according to the tenth embodiment is the same as that of the terminal 10 according to the seventh embodiment, the same reference numerals as those in FIG. Omitted where appropriate.

  This process is executed when, for example, the terminal 10 is turned on. In FIG. 29, first, the communication processing unit 131 determines whether or not the H packet transmission time has arrived and whether or not a communication packet has been received (S101), as in the seventh embodiment. One of step S102 and step S103 is executed according to the above.

  In step S103, the communication processing unit 131 identifies the type of the received communication packet, as in step S103 of the seventh embodiment. As a result of this identification, the communication processing unit 131 executes step S104 when the communication packet is a response packet (response packet), and executes step S105 when the communication packet is a route determination packet (route determination packet). If the communication packet is an SQ notification packet (SQ notification packet), step S108 is executed. It should be noted that if the communication packet is an H packet (H packet), step S141 is executed. To do.

  After execution of step S108, the communication processing unit 131 executes step S109 to step S114 as in the seventh embodiment.

  In step S <b> 141, the communication processing unit 131 increments the number of received H packets corresponding to the transmission source terminal ID in the H packet by 1 in the communicable terminal data table D ′ using the table processing unit 132. Next, the communication processing unit 131 determines whether or not the number of received H packets corresponding to the transmission source terminal ID in the H packets is equal to or greater than a predetermined reference value (for example, 4 or more) (S142). The initialization time interval and the predetermined reference value shown in FIG. 28 are determined according to specifications in consideration of the communication stability required for the PLC network 1, and can be communicated with a probability of 80% or more, for example. Is required for the PLC network 1, for example, the initialization time interval is set to five times the H packet transmission interval, and the predetermined reference value is set to four. Also, for example, the initialization time interval is set to 10 times the H packet transmission interval, and the predetermined reference value is set to 8. Alternatively, for example, when the PLC network 1 is required to be able to communicate with a probability of 90% or more, for example, the initialization time interval is set to 10 times the H packet transmission interval, and the predetermined reference value is 9 is set.

  If the result of determination in step S142 is that the number of received H packets is not greater than or equal to the predetermined reference value (No), the communication processing unit 131 returns the process to S101. On the other hand, when the number of received H packets is equal to or greater than a predetermined reference value (No), the communication processing unit 131 uses the table processing unit 132 to use an effective link flag corresponding to the transmission source terminal ID in the H packet. Is set to 1 (S143).

  Next, the communication processing unit 131 refers to the communicable terminal data table D ′ using the table processing unit 132, calculates the temporary communication cost value except for the terminal 10 whose communication cost value is 0, and determines the upper predetermined rank It is determined whether or not this is the case (S131).

  As a result of the determination, when the calculated temporary communication cost value is not higher than the upper predetermined rank (No), the communication processing unit 131 returns the process to step S101, while the calculated temporary communication cost value is higher than the predetermined upper rank. If the rank is equal to or higher than the rank (Yes), the communication processing unit 131 returns the process to step S101 after executing step S107.

  As described above, the table processing unit 132, in addition to the processing of the seventh embodiment, initializes the number of received H packets, updates the number of received H packets, updates the valid link flag, and provisional communication. In addition to the process of the seventh embodiment, the communication processing unit 131 also performs a process of transmitting a response packet when the calculated temporary communication cost value is equal to or higher than the upper predetermined rank. Do.

  By configuring the terminal 10 in this way, a process for searching for bidirectional SQ is performed only when communication with the adjacent terminal 10 is temporally stable, so that traffic in the PLC network 1 can be reduced. Only stable communication routes can be selected. In particular, even when the operation status of the home appliance connected to the PLC network 1 frequently changes and the communication quality of the PLC network 1 dynamically changes accordingly, only a highly stable communication route can be selected.

Next, another embodiment will be described.
(Eleventh embodiment)
The terminal 10 according to the ninth embodiment returns a response packet by unicast when the temporary communication cost value is equal to or higher than the upper predetermined rank, but the terminal 10 according to the eleventh embodiment Instead of storing a response packet transmission destination to which a response packet should be returned for a predetermined time, and transmitting the stored response packet transmission destination by broadcast communication after a lapse of the predetermined time, The SQ notification packet transmission destination to which the SQ notification packet is to be returned is stored for a predetermined time, and the stored SQ notification packet transmission destination is collectively transmitted by broadcast communication after the predetermined time has elapsed. . Here, the eleventh embodiment will be described based on the seventh embodiment, but the first embodiment can be based on the same.

  For this reason, as shown in FIG. 3, the terminal 10 according to the eleventh embodiment includes a setting unit (not shown) that sets whether the terminal 10a is a parent terminal 10a or a child terminal 10b, a storage unit 110, and a PLC. An interface unit 120 and a control unit 130 are provided. The storage unit 110 includes a table storage unit 111, an SQ notification transmission destination address storage unit 114, an SQ notification information storage unit 115, a response packet transmission destination address storage unit 117, and a response packet information storage unit 118. The communication processing unit 131, the table processing unit 132, the H packet transmission timer unit 133, the SQ notification transmission timer unit 135, and the response packet transmission timer unit 136 are functionally provided to the control unit 130. Prepare.

  The response packet transmission destination address storage unit 117 is an area in which the terminal ID in the terminal 10 that is the transmission source of the H packet to which the response packet is to be returned when the H packet is received from the other terminal 10 is registered. In the present embodiment, the response packet transmission destination address storage unit 117 is a terminal to which a response packet should be returned when an H packet is received from another terminal 10 and the temporary communication cost value is higher than the upper predetermined rank. 10, the terminal ID of the terminal 10 that is the transmission source of the H packet is registered. The response packet information storage unit 118 is an area for storing information included in the response packet for the terminal 10 identified by the terminal ID in association with the terminal ID registered in the response packet transmission destination address storage unit 117. . The information included in the response packet is, for example, the sequence number of the H packet acquired from the H packet.

  The response packet transmission timer unit 136 measures the passage of time and notifies the communication processing unit 131 of the response packet transmission time at predetermined time intervals.

  The communication processor 131 and the table processor 132 according to the eleventh embodiment operate as described with reference to FIG. 23 in the seventh embodiment, in that they operate as described with reference to FIG. 30 below. The other points are the same as those of the communication processing unit 131 and the table processing unit 132 according to the seventh embodiment.

  FIG. 30 is a flowchart showing an example of a communication route construction process of the terminal according to the eleventh embodiment of the present invention. Here, when the operation of the terminal 10 according to the eleventh embodiment is the same as that of the terminal 10 according to the seventh embodiment, the same reference numerals as those in FIG. Omitted where appropriate.

  This process is executed when, for example, the terminal 10 is turned on. In FIG. 30, first, the communication processing unit 131 determines whether any of the H packet transmission time, response packet transmission time, and SQ notification packet transmission time has arrived, and whether a communication packet has been received. It is determined whether or not (S161). As a result of the determination, when it is the transmission time of the SQ notification packet (transmission time of the SQ notification packet), the communication processing unit 131 executes step S162, and when it is the transmission time of the response packet (transmission time of the response packet). Step S164 is executed. If it is the H packet transmission time (H packet transmission time), Step S102 is executed. If it is a packet reception (Packet reception), Step S103 is executed. .

  In step S162, the communication processing unit 131 determines whether it is necessary to transmit an SQ notification packet. Here, when the terminal ID is stored in the SQ notification transmission destination address storage unit 114, it is determined that the SQ packet needs to be transmitted.

  As a result of this determination, when it is not necessary to transmit the SQ notification packet (No), the communication processing unit 131 returns this processing to step S161.

  On the other hand, if it is necessary to transmit the SQ notification packet as a result of this determination (Yes), the communication processing unit 131 refers to the SQ notification transmission destination address storage unit 114 and the SQ notification information storage unit 115, for example, The SQ notification packet shown in FIG. Then, the communication processing unit 131 transmits the created SQ notification packet to the PLC network 1 by broadcast communication, for example, by broadcast. The communication processing unit 131 includes the SQ notification transmission destination address storage unit 114 and the SQ notification information storage unit. The data registered in 115 (data indicating terminal ID, SQ, sequence number, etc.) is discarded (S163), and the process returns to step S161.

  In step S164, the communication processing unit 131 determines whether it is necessary to transmit a response packet. Here, when the terminal ID is stored in the response packet transmission destination address storage unit 117, it is determined that the response packet needs to be transmitted.

  As a result of this determination, when there is no need to transmit a response packet (No), the communication processing unit 131 returns this processing to step S161.

  On the other hand, if it is necessary to transmit a response packet as a result of this determination (Yes), the communication processing unit 131 refers to the response packet transmission destination address storage unit 117 and the response packet information storage unit 118, and transmits a response packet. Create Then, the communication processing unit 131 transmits the created response packet to the PLC network 1 by broadcast communication, for example, by broadcast, and the communication processing unit 131 includes the response packet transmission destination address storage unit 117 and the response packet information storage unit 118. The data (data indicating the terminal ID, sequence number, etc.) registered in (1) is discarded (S165), and the process returns to step S161.

  For example, as shown in FIG. 6H, the response packet includes an operation code, a terminal ID of the transmission source (terminal ID of the own terminal 10), and a terminal ID of the transmission destination of the response packet (first terminal ID to nth terminal). ID), and the sequence number (for the first terminal ID to for the nth terminal ID) contained in the H packet received from the terminal ID of the transmission destination. The terminal ID of the transmission destination of the response packet is stored in the response packet transmission destination address storage unit 117, and the sequence number is stored in the response packet information storage unit 118.

  In step S102, the communication processing unit 131 creates the H packet shown in FIG. 6A and transmits it to the PLC network 1 by broadcast communication, for example, by broadcast, as in the seventh embodiment, and performs processing. It returns to step S161.

  In step S103, the communication processing unit 131 identifies the type of the received communication packet, as in the seventh embodiment. As a result of this identification, the communication processing unit 131 executes step S166 when the communication packet is a response packet (response packet), and executes step S108 when the communication packet is an SQ notification packet (SQ notification packet). If the communication packet is an H packet (H packet), step S131 is executed. If the communication packet is a route determination packet (route determination packet), step S105 is executed.

  In step S166, the communication processing unit 131 determines whether or not the terminal ID of the terminal itself is accommodated in the received response packet. As a result of this determination, if the terminal ID of the own terminal is not accommodated (No), the communication processing unit 131 returns the process to step S161, whereas if the terminal ID of the own terminal is accommodated (Yes) ) Executes step S167.

  In step S167, the communication processing unit 131 uses the table processing unit 132 to set the transmission source terminal ID contained in the response packet as the transmission destination terminal ID of the SQ notification packet in the SQ notification transmission destination address storage unit 114. sign up. Then, the communication processing unit 131 uses the table processing unit 132 to obtain the SQ from the received signal strength of the response packet, associates it with the terminal ID, and transmits the response packet from the terminal 10 that has transmitted the response packet to the terminal 10. Data representing the SQ and the sequence number of the response packet are registered in the SQ notification information storage unit 115, and the process returns to step S161.

  In step S108, the communication processing unit 131 determines whether or not the SQ notification packet is received within a predetermined time after transmitting the response packet, as in step S108 of the seventh embodiment.

  As a result of this determination, when the SQ notification packet is not received within the predetermined time (No), the communication processing unit 131 returns the process to step S161. On the other hand, as a result of this determination, when the SQ notification packet is received within a predetermined time (Yes), it is determined whether or not the terminal ID of the own terminal is accommodated in the received response packet (S168). As a result of this determination, if the terminal ID of the own terminal is not accommodated (No), the communication processing unit 131 returns the process to step S161, whereas if the terminal ID of the own terminal is accommodated (Yes) ) Executes step S169.

  In step S169, the communication processing unit 131 uses the table processing unit 132 to calculate a communication cost value based on the SQ corresponding to the own terminal accommodated in the SQ notification packet, and executes the process S111.

  After execution of step S111, the communication processing unit 131 executes steps S112 to S114 as in the seventh embodiment.

  In step S131, the communication processing unit 131 refers to the communicable terminal data table D using the table processing unit 132, calculates the temporary communication cost value except for the terminal 10 whose communication cost value is 0, and determines the upper predetermined rank It is determined whether this is the case. As a result of the determination, if the calculated temporary communication cost value is not higher than the upper predetermined rank, the communication processing unit 131 returns the process to step S161, while the calculated temporary communication cost value is higher than the upper predetermined rank. If there is, the communication processing unit 131 executes Step S170.

  In step S170, the communication processing unit 131 uses the table processing unit 132 to register the transmission source terminal ID accommodated in the H packet in the response packet transmission destination address storage unit 117 as a transmission packet terminal ID. Then, in association with the terminal ID, the data representing the SQ from the terminal 10 that is the source of the H packet to the terminal 10 and the sequence number of the H packet are registered in the response packet information storage unit 118, and the process is performed. Return to S161.

  In step S105, as in the seventh embodiment, when the terminal 10 is the child terminal 10b, the communication processing unit 131 refers to the communicable terminal data table D and follows the received route determination packet. Is added to the next higher-level terminal 10 by unicast. On the other hand, when the terminal 10 is the parent terminal 10a, the communication processing unit 131 uses the table processing unit 132 to set the transmission terminal ID and the upper terminal ID included in the route determination packet as the established communication route. The communication route table is updated by registering in the communication route table. Thereafter, the communication processing unit 131 returns the process to step S161.

  By configuring the terminal 10 in this way, when the terminal 10 receives the response packet, the SQ notification packet is not transmitted by unicast, but includes SQ notifications for a plurality of terminals 10 at predetermined time intervals. Since the SQ notification packet is transmitted by broadcast, traffic in the PLC network 1 can be reduced. In addition, by configuring the terminal 10 in this way, when the terminal 10 receives an H packet, a response packet is not transmitted by unicast, but a response in which a plurality of terminals 10 minutes are collected at predetermined time intervals. Since the packet is transmitted by broadcast, traffic in the PLC network 1 can be reduced.

Next, another embodiment will be described.
(Twelfth embodiment)
The terminal 10 according to the eleventh embodiment transmits a response packet in which a plurality of terminals 10 minutes are gathered by broadcast communication at predetermined time intervals, but the terminal 10 according to the twelfth embodiment Instead of this, information to be accommodated in a response packet including a plurality of terminals 10 minutes is accommodated in an H packet (H packet with response) and transmitted by broadcast communication. Here, the twelfth embodiment will be described based on the eleventh embodiment, but the first embodiment can be based on the same.

  For this reason, the terminal 10 according to the twelfth embodiment, as shown in FIG. 3, a setting means (not shown) for setting whether the terminal 10 is a parent terminal 10a or a child terminal 10b, a storage unit 110, and a PLC An interface unit 120 and a control unit 130 are provided. The storage unit 110 includes a table storage unit 111, an SQ notification transmission destination address storage unit 114, an SQ notification information storage unit 115, a response packet transmission destination address storage unit 117, and a response packet information storage unit 118. The communication processing unit 131, the table processing unit 132, the H packet transmission timer unit 133, and the SQ notification transmission timer unit 135 are functionally included in the control unit 130.

  The communication processing unit 131 and the table processing unit 132 according to the twelfth embodiment operate as described with reference to FIG. 31 in the eleventh embodiment that operates as described with reference to FIG. The other points are the same as those of the communication processing unit 131 and the table processing unit 132 according to the eleventh embodiment.

  FIG. 31 is a flowchart showing an example of a communication route construction process of the terminal according to the twelfth embodiment of the present invention. Here, when the operation of the terminal 10 according to the twelfth embodiment is the same as that of the terminal 10 according to the eleventh embodiment, the same reference numerals as those in FIG. Omitted as appropriate.

  This process is executed when, for example, the terminal 10 is turned on. In FIG. 31, first, the communication processing unit 131 determines whether any one of the H packet transmission time and the SQ notification packet transmission time has arrived and whether a communication packet has been received. (S181). As a result of the determination, if it is the transmission time of the SQ notification packet (transmission time of the SQ notification packet), the communication processing unit 131 executes step S162, and if it is the transmission time of the H packet (transmission time of the H packet). Step S182 is executed, and if the packet is received (packet reception), Step S103 is executed.

  In step S162, the communication processing unit 131 determines whether it is necessary to transmit the SQ notification packet, as in the eleventh embodiment. As a result of this determination, when the communication processing unit 131 determines that it is not necessary to transmit the SQ notification packet (No), the communication processing unit 131 returns the process to step S181, and determines that it is necessary to transmit the SQ notification packet. In the case (Yes), similarly to the eleventh embodiment, after executing step S163, the process returns to step S181.

  In step S182, the communication processing unit 131 determines whether it is necessary to transmit a response packet. Here, when the terminal ID is stored in the response packet transmission destination address storage unit 117, it is determined that the response packet needs to be transmitted.

  As a result of this determination, when it is determined that it is not necessary to transmit a response packet (No), the communication processing unit 131 creates a normal H packet shown in FIG. For example, the broadcast is transmitted to the PLC network 1 (S184), and the process returns to step S181.

  On the other hand, if it is determined that the response packet needs to be transmitted as a result of this determination (Yes), the communication processing unit 131 refers to the response packet transmission destination address storage unit 117 and the response packet information storage unit 118. Then, an H packet with a response is created. Then, the communication processing unit 131 transmits the created H packet with response to the PLC network 1 by broadcast communication, for example, by broadcast. The communication processing unit 131 includes a response packet transmission destination address storage unit 117 and a response packet information storage. The data (data indicating the terminal ID and sequence number) registered in the unit 118 is discarded (S183), and the process returns to step S181.

  For example, as shown in FIG. 6I, this H packet with a response includes an operation code, a terminal ID of the transmission source (terminal ID of the own terminal 10), a sequence number for the H packet, a communication cost value, the number of hops, a response The packet transmission destination terminal ID (first terminal ID to nth terminal ID), and the sequence number contained in the H packet received from this transmission destination terminal ID (for the first terminal ID to nth terminal ID) including. The terminal ID of the destination of the response packet is stored in the response packet destination address storage unit 117, and the sequence numbers for the first terminal ID to the n-th terminal ID are the response packet information storage unit. 118 is stored.

  In step S103, the communication processing unit 131 identifies the type of the received communication packet, as in the seventh embodiment. As a result of this identification, the communication processing unit 131 executes step S185 when the communication packet is an H packet with a response (H packet with response), and when the communication packet is a route determination packet (route determination packet). Step S105 is executed, and if the communication packet is an SQ notification packet (SQ notification packet), Step S108 is executed.

  In step S185, the communication processing unit 131 determines whether or not the terminal ID of the terminal itself is accommodated in the received packet with response. As a result of this determination, if the terminal ID of the own terminal is not accommodated (No), the communication processing unit 131 executes step S131, while the terminal ID of the own terminal is accommodated (Yes). In the same manner as in the eleventh embodiment, after executing step S167, step S131 is executed.

  In step S131, as in the eleventh embodiment, the communication processing unit 131 calculates a temporary communication cost value for the predetermined terminal 10 using the table processing unit 132, and determines whether it is equal to or higher than the upper predetermined rank. To do. As a result of the determination, when the calculated temporary communication cost value is not equal to or higher than the upper predetermined rank (No), the communication processing unit 131 returns the process to step S181, while the calculated temporary communication cost value is higher than the predetermined upper rank. If the rank is equal to or higher than the rank (Yes), the communication processing unit 131 returns the process to step S181 after executing step S170 as in the eleventh embodiment.

  After execution of step S108, the communication processing unit 131 executes step S168 and step S169, and subsequently executes step S111 to step S114, as in the eleventh embodiment.

  In step S105, as in the case of the eleventh embodiment, when the terminal 10 is the child terminal 10b, the communication processing unit 131 refers to the communicable terminal data table D and follows the received route determination packet. Is added to the next higher-level terminal 10 by unicast. On the other hand, when the terminal 10 is the parent terminal 10a, the communication processing unit 131 uses the table processing unit 132 to set the transmission terminal ID and the upper terminal ID included in the route determination packet as the established communication route. The communication route table is updated by registering in the communication route table. Thereafter, the communication processing unit 131 returns the process to step S181.

  By configuring the terminal 10 in this way, compared with the terminal 10 in the eleventh embodiment, the traffic in the PLC network 1 can be further reduced by using the H packet also as a response packet.

  In the above-described eighth to twelfth embodiments, as in the second embodiment, the child terminal 10b that has not established a communication route with the parent terminal 10a transmits a response packet while transmitting an H packet. It may be configured not to transmit. In this case, the terminal 10 further includes a HP transmission enable flag storage unit 112 functionally in the storage unit 110 and a flag presence / absence determination unit 134 functionally further in the control unit 130, as indicated by a broken line in FIG.

  In the eighth to twelfth embodiments described above, the terminal 10 ends the search for the communication route when a communication cost value equal to or higher than a predetermined level capable of satisfactorily communicating with the parent terminal 10a is obtained. May be configured. In this case, as indicated by a broken line in FIG. 3, the terminal 10 further includes an HP transmission enable flag storage unit 112 and an HP reception enable flag storage unit 113 functionally in the storage unit 110, and the flag presence / absence determination unit 134 is a control unit. 130 is further functionally provided.

  Furthermore, in the first to twelfth embodiments described above, SQ is a value based on the received signal strength, but may be a value based on a packet error rate or a bit error rate.

  In the first to twelfth embodiments, the terminal 10 having the same content is set as “parent” to function as the parent terminal 10a, and is set to “child” so that the child terminal 10b and Although the functioning configuration is employed, the present invention is not limited to this, and dedicated terminals may be used for the parent terminal 10a and the child terminal 10b.

  In the first to twelfth embodiments, the communication route construction method of the present invention is used in a PLC network. However, the method is applied to other communication networks such as a wireless LAN such as a low-power radio. Also good. However, the present invention is more effective when used in a communication network in which the communication speed between the terminals 10 is relatively low and the capacity of the memory built in each terminal 10 is relatively small as in the PLC network 1.

It is a figure which shows the power line carrier communication network which concerns on the 1st Embodiment of this invention. It is a figure which shows the communication route constructed | assembled between the terminals in the power line carrier communication network shown in FIG. It is a block diagram of the terminal shown in FIG. It is a figure which shows an example of the communicable terminal data table D. FIG. It is a flowchart which shows an example of the communication route construction process of the terminal shown in FIG. It is a figure which shows an example of a communication packet. It is a figure which shows an example of the communication sequence for constructing | assembling the communication route between terminals in the power line carrier communication network shown in FIG. It is a flowchart (the 1) which shows an example of the communication route construction process of the terminal which concerns on the 2nd Embodiment of this invention. It is a flowchart (the 2) which shows an example of the communication route construction process of the terminal which concerns on the 2nd Embodiment of this invention. It is a figure which shows an example of the communication sequence for constructing | assembling the communication route between terminals in the 2nd Embodiment of this invention. It is a flowchart (the 1) which shows an example of the communication route construction process of the terminal which concerns on the 3rd Embodiment of this invention. It is a flowchart (the 2) which shows an example of the communication route construction process of the terminal which concerns on the 3rd Embodiment of this invention. It is a figure which shows an example of the communication sequence for constructing | assembling the communication route between terminals in the 3rd Embodiment of this invention. It is a flowchart (the 1) which shows an example of the communication route construction process of the terminal which concerns on the 4th Embodiment of this invention. It is a flowchart (the 2) which shows an example of the communication route construction process of the terminal which concerns on the 4th Embodiment of this invention. It is a figure which shows an example of the communication sequence for constructing | assembling the communication route between terminals in the 4th Embodiment of this invention. It is a flowchart (the 1) which shows an example of the communication route construction process of the terminal which concerns on the 5th Embodiment of this invention. It is a flowchart (the 2) which shows an example of the communication route construction process of the terminal which concerns on the 5th Embodiment of this invention. It is a figure which shows an example of the communication sequence for building the communication route between terminals in the 5th Embodiment of this invention. It is a flowchart (the 1) which shows an example of the communication route construction process of the terminal which concerns on the 6th Embodiment of this invention. It is a flowchart (the 2) which shows an example of the communication route construction process of the terminal which concerns on the 6th Embodiment of this invention. It is a figure which shows an example of the communication sequence for constructing | assembling the communication route between terminals in the 6th Embodiment of this invention. It is a flowchart which shows an example of the communication route construction process of the terminal which concerns on the 7th Embodiment of this invention. It is a flowchart which shows an example of the communication route construction process of the terminal which concerns on the 8th Embodiment of this invention. It is a figure which shows an example of the communicable terminal data table D for demonstrating the calculation example of a temporary communication cost value. It is a flowchart which shows an example of the communication route construction process of the terminal which concerns on the 9th Embodiment of this invention. It is a figure which shows an example of the communicable terminal data table D 'in the 10th Embodiment of this invention. It is a flowchart which shows the process which initializes the reception number of H packet. It is a flowchart which shows an example of the communication route construction process of the terminal which concerns on the 10th Embodiment of this invention. It is a flowchart which shows an example of the communication route construction process of the terminal which concerns on the 11th Embodiment of this invention. It is a flowchart which shows an example of the communication route construction process of the terminal which concerns on the 12th Embodiment of this invention.

Explanation of symbols

1 Power line carrier communication network (an example of a communication network)
10a Parent terminal (an example of a first communication terminal)
10b Child terminal (example of second communication terminal)
110 storage unit 111 table storage unit 112 hello packet transmittable flag storage unit 113 hello packet receivable 114 SQ notification transmission destination address storage unit 115 SQ notification information storage unit 116 hello packet transmission flag storage unit 117 with route determination response packet transmission destination address Storage unit 118 Response packet information storage unit 120 PLC interface unit (an example of a communication unit)
130 Control Unit 131 Communication Processing Unit 132 Table Processing Unit 133 Hello Packet Transmission Timer Unit 134 Flag Presence Determination Unit 135 SQ Notification Transmission Timer Unit 136 Response Packet Transmission Timer Unit

Claims (15)

In a communication route construction method for constructing a communication route between a parent communication terminal and a child communication terminal in a communication network including a parent communication terminal and a plurality of child communication terminals,
A communication quality notification step in which the communication terminal transmits a notification communication packet including communication quality information indicating communication quality in a communication route between the communication terminal and the parent communication terminal to the communication network by broadcast communication;
When the child communication terminal receives the notification communication packet, it acquires the communication quality from the communication terminal of the transmission source that transmitted the notification communication packet to the own communication terminal, and sends the notification communication packet from the own communication terminal. A communication quality acquisition step of acquiring the communication quality to the transmission source communication terminal,
Based on the bidirectional communication quality acquired in the communication quality acquisition step, and the communication quality information included in the received notification communication packet, the child communication terminal that has received the notification communication packet. Communication that establishes a communication route between the parent communication terminal and the own communication terminal only when the communication quality between the other communication terminal and the own communication terminal is calculated and the calculated communication quality satisfies a predetermined condition A route construction step,
The communication quality acquisition step was included in the communication quality from the communication terminal of the transmission source of the notification communication packet obtained based on the received notification communication packet to the own communication terminal, and the received notification communication packet A temporary communication quality between the parent communication terminal and the own communication terminal is calculated based on the communication quality information, and is executed only when the calculated temporary communication quality satisfies a predetermined condition. How to build a communication route. The communication route construction method according to claim 1, wherein the predetermined condition in the communication quality acquisition step is that the calculated temporary communication quality is equal to or higher than a predetermined reference value. Wherein the predetermined condition in the communication quality acquisition step, characterized in that the temporary communication quality thus calculated is within a predetermined rank from the upper of the temporary communication quality can be calculated between the communication terminal and the own communication terminal of the parent The communication route construction method according to claim 1. The communication quality acquisition step is executed only when the reception probability of the notification communication packet within a predetermined time is equal to or higher than a predetermined reference value . The communication route construction method according to item 1. The communication route construction method according to any one of claims 1 to 4 , wherein the predetermined condition in the communication route construction step is that the calculated communication quality is equal to or higher than a predetermined reference value . The predetermined condition in the communication route construction step is that the calculated communication quality is within a predetermined order from the top among communication routes constructed between the parent communication terminal and the own communication terminal. The communication route construction method according to any one of claims 1 to 4 . The communication quality notification step is executed only when the communication terminal establishes a communication route with the parent communication terminal. The communication route construction method according to the item. The communication quality acquisition step is executed when a communication route between the parent communication terminal and the own communication terminal whose communication quality is equal to or higher than a predetermined reference value is constructed by the communication route construction step. method for constructing a communication route according to any one of claims 1 to 7, characterized in that but is prohibited. The communication quality acquisition step includes
A first step of obtaining communication quality from a communication terminal of a transmission source that has transmitted the notification communication packet based on the received notification communication packet to a local communication terminal when the child communication terminal receives the notification communication packet; ,
The child communication terminal that has received the notification communication packet transmits a response communication packet that requests notification of communication quality from the communication terminal to the transmission source communication terminal that has transmitted the notification communication packet. A second step of returning to the original communication terminal;
Based on the response communication packet received from the child communication terminal that has received the notification communication packet, the communication terminal that has transmitted the notification communication packet communicates with itself from the child communication terminal that has received the notification communication packet. A third step of returning a communication quality notification communication packet including the communication quality to the child communication terminal that has received the notification communication packet in response to the communication quality to the terminal;
The child communication terminal that has received the notification communication packet includes a fourth step of receiving the communication quality notification communication packet from a communication terminal that has transmitted the notification communication packet. The communication route construction method according to claim 8 . The communication quality acquisition step includes
A first step of obtaining communication quality from a communication terminal of a transmission source that has transmitted the notification communication packet based on the received notification communication packet to a local communication terminal when the child communication terminal receives the notification communication packet; ,
The transmission source that the child communication terminal that has received the notification communication packet transmits the plurality of notification communication packets from its own communication terminal to each communication terminal in the transmission source of the plurality of notification communication packets received within a predetermined time A second step of transmitting a response communication packet collectively requesting notification of each communication quality to each communication terminal in the broadcast network to the communication network;
When the communication terminal that has received the response communication packet is addressed to its own device, based on the response communication packet received from the child communication terminal that has transmitted the response communication packet, the child of the child that has transmitted the response communication packet. A third step of obtaining the communication quality from the communication terminal to the own communication terminal and returning a communication quality notification communication packet including the communication quality to the child communication terminal that has transmitted the response communication packet;
Communication terminal of the child receiving the notification communication packet, claims 1 to 8, characterized in that it comprises a fourth step of receiving the communication quality notification communication packet from the communication terminal receiving the response communication packet The communication route construction method according to any one of the above. The communication route construction method according to claim 10 , wherein the response communication packet is also used as the notification communication packet. The communication quality acquisition step includes
A first step of obtaining communication quality from a communication terminal of a transmission source that has transmitted the notification communication packet based on the received notification communication packet to a local communication terminal when the child communication terminal receives the notification communication packet; ,
The child communication terminal that has received the notification communication packet transmits a response communication packet that requests notification of communication quality from the communication terminal to the transmission source communication terminal that has transmitted the notification communication packet. A second step of returning to the original communication terminal;
Based on the response communication packet received from the child communication terminal that has received the notification communication packet, the communication terminal that has transmitted the notification communication packet communicates with itself from the child communication terminal that has received the notification communication packet. While obtaining the communication quality to the terminal, each communication terminal at the transmission source of the plurality of response communication packets received within a predetermined time, from each communication terminal at the transmission source that has transmitted the plurality of response communication packets obtained A third step of transmitting a communication quality notification communication packet in which notification of each communication quality to the communication terminal is collected to the communication network by broadcast communication;
When the child communication terminal that has received the notification communication packet has received the communication quality notification communication packet, the transmission source that has transmitted the notification communication packet corresponding to its own device included in the communication quality notification communication packet The communication route construction method according to any one of claims 1 to 8, further comprising: a fourth step of acquiring communication quality from the communication terminal to the own communication terminal. The communication route construction method according to claim 12 , wherein the communication quality notification communication packet is also used as the notification communication packet. The communication route construction step further comprises a step of transmitting the route determination communication packet including the communication route between the constructed parent communication terminal and the own communication terminal toward the parent communication terminal,
The communication route construction method according to any one of claims 1 to 13 , wherein the route determination communication packet is also used as the notification communication packet. A communication quality notification means for transmitting a notification communication packet including communication quality information indicating communication quality in a communication route between the own communication terminal and a parent communication terminal in the communication network to the communication network by broadcast communication;
When the notification communication packet is received , communication quality from the communication terminal that is the transmission source of the notification communication packet obtained based on the received notification communication packet to the own communication terminal, and included in the received notification communication packet The temporary communication quality between the parent communication terminal and the own communication terminal is calculated based on the received communication quality information, and only when the calculated temporary communication quality satisfies a predetermined condition, the notification communication packet Communication quality acquisition means for acquiring communication quality from the communication terminal of the transmission source to the communication terminal of the transmission source, and acquiring communication quality from the communication terminal to the communication terminal of the transmission source that transmitted the notification communication packet;
Based on the bidirectional communication quality acquired by the communication quality acquisition means and the communication quality information included in the received notification communication packet, the communication quality between the parent communication terminal and the own communication terminal And a communication route construction means for constructing a communication route between the parent communication terminal and the own communication terminal only when the calculated communication quality satisfies a predetermined condition. A communication terminal that establishes a communication route with other communication terminals.

Images