JP2019213008A - Communication terminal, communication system, and program - Google Patents

Abstract

To provide a communication terminal, a communication system, and a program that can reduce a possibility that a specific higher-level candidate may be selected as a higher-level communication terminal in a communication system in which multi-hop communication is performed between a plurality of communication devices including a master unit and a plurality of slave units.SOLUTION: A communication terminal 100 includes a communication unit 102 and a control unit 101 that controls the communication unit 102. The control unit 101 performs selection processing of selecting a higher-level communication terminal from a plurality of higher-level candidates on the basis of the number of lower-level communication terminals connected to each of the plurality of higher-level candidates.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a communication terminal, a communication system, and a program. More specifically, the present disclosure relates to a communication terminal, a communication system, and a program that perform multi-hop communication.

  Conventionally, there has been a communication system that performs multi-hop communication between a plurality of communication devices including a parent device and a plurality of child devices (see, for example, Patent Document 1). In this communication system, each slave unit calculates the total cost of the route cost and the link cost, selects the terminal with the minimum total cost as the upper terminal, and performs communication.

Japanese Patent Laying-Open No. 2015-115643

  In the communication system disclosed in Patent Document 1, since the slave unit selects the terminal having the lowest total cost of the route cost and the link cost as the higher order terminal, a plurality of slave units have a specific terminal (higher candidate) as the higher order terminal. There was a possibility of selecting as a terminal (high-order communication terminal).

An object of the present disclosure is to provide a communication terminal, a communication system, and a program that can reduce the possibility that a specific upper candidate is selected as an upper communication terminal.

  A communication terminal according to an aspect of the present disclosure is the communication terminal of a communication system in which a plurality of communication terminals perform multi-hop communication. The communication terminal includes a communication unit and a control unit that controls the communication unit. The said control part performs the selection process which selects a high-order communication terminal from the said some high-order candidate based on the terminal number of the low-order communication terminal connected to each of a some high-order candidate.

  A communication system according to an aspect of the present disclosure includes a plurality of the communication terminals. Multi-hop communication is performed between the plurality of communication terminals.

  A program according to an aspect of the present disclosure is a selection process for selecting a higher communication terminal from among the plurality of higher candidates based on the number of lower communication terminals connected to each of the plurality of higher candidates in the computer system. Is a program for executing

  According to the present disclosure, it is possible to provide a communication terminal, a communication system, and a program that can reduce the possibility that a specific upper candidate is selected as an upper communication terminal.

FIG. 1 is a system configuration diagram of a communication system including a communication terminal according to an embodiment of the present disclosure. FIG. 2 is a block diagram of the above communication terminal. FIG. 3 is a flowchart for explaining the communication terminal selection process. FIG. 4 is a system configuration diagram of the above communication system. FIG. 5 is an explanatory diagram illustrating communication terminal selection processing according to Modification 1 of the embodiment of the present disclosure. FIG. 6 is an explanatory diagram illustrating communication terminal selection processing according to Modification 3 of the embodiment of the present disclosure.

(Embodiment)
(1) Overview FIG. 1 is a schematic diagram of a communication system 600 including the communication terminal 100 (see FIG. 2) of the present embodiment.

  The communication system 600 of this embodiment is used in facilities, such as a factory and an office building, for example. A communication terminal 100 including a parent device 10 and a plurality of child devices 20 is installed in the facility, and the parent device 10 and the plurality of child devices 20 are configured by the communication terminal 100.

  The parent device 10 and the plurality of child devices 20 perform multi-hop communication. Here, when the child devices 20 are distinguished by the number of hops, the child device 20 with the hop number 1 is the child device 21, the child device 20 with the hop number 2 is the child device 22, and the child device 20 with the hop number 3 is the child device. The slave unit 20 having the machine 23 and the hop count of 4 is referred to as a slave unit 24. Further, individual identification numbers are assigned to the plurality of slave units 20 in order to identify the individual slave units 20 in the communication system 600, and the identification numbers are displayed in a circle representing the slave unit 20 in FIG. doing. In the following description, when the individual slave unit 20 is described, for example, the slave unit 21 (20) having the identification number “101” may be described as the slave unit 21 [101] or the slave unit 20 [101].

  Further, in the communication system 600 of the present embodiment, the control device 300 is connected to the parent device 10, and each child device 20 is controlled by the control device 300 (for example, an electric device such as a lighting device or an air conditioner). 400 is connected. In FIG. 1, the device 400 is not shown for some of the slave units 20.

  Here, since the control signal output from the control device 300 is transmitted from the parent device 10 to the child device 20 to which the device 400 to be controlled is connected, the device 400 to be controlled can be operated according to the control signal. it can. Therefore, in the communication system 600 of the present embodiment, a control system that controls the device 400 can be constructed by connecting the control device 300 to the parent device 10 and connecting the device 400 to be controlled to the child device 20. . The communication system 600 is not limited to the one used in the control system, and the monitoring device connected to the parent device 10 is connected to the child device 20 as a data collection system that collects data from the device connected to the child device 20. It may be used in a monitoring system for monitoring the state of a connected device. It is not essential that the devices 400 are connected to all the child devices 20, and the devices 400 may not be connected to some of the child devices 20. The subunit | mobile_unit 20 to which the apparatus 400 is not connected functions as a repeater (repeater).

  FIG. 2 is a block diagram of the communication terminal 100 of the present embodiment. In the present embodiment, the same communication terminal 100 is used for the parent device 10 and the child device 20. For example, the communication terminal 100 functions as the parent device 10 by being set to “parent device” using a setting unit such as a jumper switch or a changeover switch, and the child device 20 by being set to “child device”. Function as.

  The communication terminal 100 according to the present embodiment is used in a communication system 600 in which a plurality of communication terminals 100 perform multihop communication. The communication terminal 100 includes a communication unit 102 and a control unit 101 that controls the communication unit 102. Based on the number of lower communication terminals connected to each of the plurality of upper candidates, the control unit 101 performs a selection process for selecting the upper communication terminal from among the plurality of upper candidates.

  The communication system 600 of this embodiment includes a plurality of communication terminals 100 and performs multi-hop communication between the plurality of communication terminals 100.

  Here, the “higher-level communication terminal” of the communication terminal 100 (slave device 20) is a communication terminal connected to the upper level of the communication terminal 100 via the link 500. In the configuration example of FIG. 1, the upper communication terminal of the slave unit 22 [106] is the slave unit 21 [102]. A “higher candidate” of a communication terminal 100 is a communication terminal that can be a higher communication terminal of the communication terminal 100. Among communication terminals having a smaller hop number than the communication terminal 100, direct communication with the communication terminal 100 is possible. It is a possible communication terminal. For example, the top candidate of the slave unit 22 [106] is a slave unit that can directly communicate with the slave unit 22 [106] among the slave units 21 having a hop count of one. Further, the “lower communication terminal” of the communication terminal 100 is a communication terminal connected to a lower level of the communication terminal 100 via the link 500. In the present embodiment, the lower communication terminal of the communication terminal 100 is a communication terminal that can directly communicate with the communication terminal 100 among all communication terminals connected to the lower level of the communication terminal 100. In the configuration example of FIG. 1, the lower-level communication terminals of the slave unit 22 [106] are the slave unit 23 [111] and the slave unit 23 [112].

  In the communication terminal 100 of the present embodiment, since a higher communication terminal is selected from a plurality of higher candidates based on the number of lower communication terminals, a specific higher candidate (communication terminal 100) is selected as the higher communication terminal. The possibility of being reduced can be reduced. Therefore, it is possible to reduce the possibility that lower communication terminals are connected to a specific higher candidate (communication terminal 100), and to reduce the possibility of communication loads being concentrated on a specific higher candidate. In the following description, the number of lower communication terminals of a certain communication terminal 100 is also referred to as the lower terminal number.

(2) Details (2.1) Configuration The communication terminal 100 according to the present embodiment includes a control unit 101, a communication unit 102, a device interface 103, and a storage unit 104, as shown in FIG.

  The control unit 101 controls the overall operation of the communication terminal 100 and controls the communication of the communication unit 102. The control unit 101 is composed of, for example, a microcomputer having a processor and a memory. That is, the control unit 101 is realized by a computer system having a processor and a memory. Then, the computer system functions as the control unit 101 when the processor executes a predetermined program. The program executed by the processor may be recorded in advance in the storage unit 104, or may be provided by being recorded through a telecommunication line such as the Internet, or in a non-temporary recording medium such as a memory card.

  The communication unit 102 is a communication interface for communicating with other communication terminals 100. As an example, the communication unit 102 is a power line communication (PLC) communication interface that uses a power line as a communication line and superimposes a signal on the power line. The communication terminal 100 of this embodiment is used by being connected to a power outlet installed in a facility. Therefore, the communication terminal 100 can communicate with other communication terminals 100 installed in the facility and connected to the power line by using the power line installed in the facility as a communication line. The communication unit 102 is not limited to the one that communicates by the power line carrier communication method, and may be a communication interface that communicates by a wired communication method other than the power line carrier communication method, or may be a communication interface that communicates by a wireless communication method.

  The device interface 103 is an interface for exchanging (input / output) data with the control device 300 or the device 400 connected to the communication terminal 100. The device interface 103 is a communication interface compliant with, for example, an Ethernet (registered trademark) standard.

  The storage unit 104 is a non-temporary recording medium, and includes a nonvolatile memory such as a ROM, an electrically rewritable nonvolatile memory such as an EEPROM, and a volatile memory such as a RAM. The memory | storage part 104 memorize | stores the link information etc. regarding the communication route and the communication terminal (other communication terminals 100 which can be communicated directly). The storage unit 104 stores a program such as a control program for operating the communication terminal 100, information necessary for executing the program, and the like.

  In the communication system 600 of the present embodiment, a unique identification number is assigned to each of the parent device 10 and the child device 20, and the identification number assigned to the own terminal is also stored in the storage unit 104 of each communication terminal 100. ing. Each communication terminal 100 is pre-assigned with a device ID such as a serial number (manufacturing number) or a MAC address, and the storage unit 104 of each communication terminal 100 stores this device ID in advance. A communication packet transmitted and received by the communication terminal 100 is subjected to communication control by adding this device ID.

(2.2) Operation Next, the operation of the communication system 600 of the present embodiment will be described.

  The parent device 10 and the child device 20 select a communication route according to, for example, a proactive routing protocol, and information on the communication route is stored in the storage unit 104 of the parent device 10 and the child device 20. Note that the routing protocol adopted by the communication system 600 is not limited to the CMSR, and may be a reactive type protocol or a proactive type protocol.

  For example, when the parent device 10 transmits transmission data including control data to the child device 23 [110], the transmission data transmitted from the parent device 10 includes the child device 21 [101] and the child device 22 [105]. To the slave unit 23 [110]. As described above, the parent device 10 can transmit transmission data to the child device 23 [110] that cannot perform direct communication, and the communication range can be expanded.

  Base unit 10 and handset 20 periodically broadcast and transmit hello packets (hereinafter also referred to as “H packets”), and exchange information such as link information with peripheral communication terminals 100. The H packet is a communication packet in which each communication terminal 100 notifies the other communication terminals 100 of the existence of its own terminal. Further, the H packet transmitted by the communication terminal 100 serving as the child device 20 contains communication route information indicating the communication route from the own terminal to the parent device 10, route quality information indicating the communication quality of this communication route, and the like. The The communication route information includes, for example, the identification number of the communication terminal 100 that passes through the communication route from the child device 20 to the parent device 10. The route quality information is information representing the communication quality of the communication route, and is a value based on, for example, the SN ratio, communication speed, bit error rate, packet error rate, and the like. In the present embodiment, the H packet includes terminal number information related to the number of other communication terminals 100 (lower communication terminals) connected to the lower level of the own terminal. The parent device 10 and the child device 20 can update the communication route based on H packets periodically transmitted from the surrounding communication terminals 100. Further, the master unit 10 and the slave unit 20 update the information on the number of lower-level communication terminals connected to the lower level (lower-level terminal number information) based on the communication route information.

  Here, the operation when a new slave 20 enters the communication system 600 will be described with reference to FIGS. 1 and 3.

  In the newly entered child device 20 (the child device 20 with the identification number “115” given after entry), the communication unit 102 is broadcasted from the child device 20 (higher candidate) that exists in a communicable range. H packet is received. The control unit 101 acquires the number-of-terminals information included in the H packet transmitted from the top candidate slave unit 20 via the communication unit 102 (S1). For example, when the slave unit 20 [115] can directly communicate with the slave unit 22 [107], the slave unit 22 [108], the slave unit 23 [114], and the slave unit 23 [116], the slave unit 20 [115] 115] acquires the number-of-terminals information from these slave units 20. The control unit 101 of the slave unit 20 [115] sets the slave units 22 [107] and 22 [108] having a small number of hops among the slave units 20 as higher candidates.

  Then, the control unit 101 of the child device 20 [115] selects the child device 20 having the smallest number of lower-order terminals based on the number-of-terminals information acquired from the upper candidate child device 22 [107] and the child device 22 [108]. A selection process for selecting as an upper communication terminal is performed (S2). For example, if the number of lower terminals of the child device 22 [107] is 20 and the number of lower terminals of the child device 22 [108] is 10, the control unit 101 of the child device 20 [115] places the child device 22 [108] as the upper terminal. Select as communication terminal. And the control part 101 of the subunit | mobile_unit 20 [115] performs the joining process to the communication network comprised by the communication system 600 with respect to the subunit | mobile_unit 22 [108] (S3). In the present embodiment, the entry process is a process when a new child device 20 enters the communication network, and a child device 20 that has already entered the communication network switches to a higher communication terminal and enters the communication network. Repair processing.

  As described above, in the present embodiment, when a new slave unit 20 enters the communication system 600, the control unit 101 of the slave unit 20 (communication terminal 100) can select from a plurality of higher rank candidates (slave units 20). An upper candidate having a lower number of lower terminals is selected as an upper communication terminal. Therefore, it is possible to reduce the possibility that many lower-level communication terminals are connected to a specific communication terminal 100. Therefore, the possibility that the communication load is concentrated on the specific communication terminal 100 can be reduced.

  In the present embodiment, the control unit 101 of the slave unit 20 (communication terminal 100) performs the selection process based on the number of lower communication terminals having only a plurality of higher candidates. The selection process may be performed in consideration of the above.

  For example, in the above selection process, the control unit 101 of the slave unit 20 (communication terminal 100) may perform the selection process based on the first terminal number and the second terminal number. The number of first terminals is the number of upper candidate lower terminals with which the own terminal can directly communicate. The second number of terminals is the number of communication terminals connected to the lower order of the higher order communication terminals connected to each of the plurality of higher order candidates and having a smaller hop count than the higher order candidates.

  In the configuration example of FIG. 1, when the child device 20 [115] selects the upper communication terminal, the child device 21 [102] is connected to the higher rank of the child device 22 [107], which is the higher candidate, and is a higher candidate. The slave unit 21 [103] is connected to the host unit 22 [108].

  Therefore, the control unit 101 of the slave unit 20 [115] includes the slave unit 22 [107] and the first terminal number that is the number of lower terminals of the slave unit 22 [108] and the slave unit 21 [102] and The upper communication terminal is selected based on the second terminal number that is the lower terminal number of the slave unit 21 [103].

  For example, the control unit 101 of the child device 20 [115] includes the total value N1 of the first terminal number of the child device 22 [107] and the second terminal number of the child device 21 [102] and the child device 22 [108]. And the total value N2 of the second terminal number of the slave unit 21 [103] are compared. For example, when the total value N1 is smaller than the total value N2, the control unit 101 of the slave unit 20 [115] selects the slave unit 22 [107] as the upper communication terminal, and the total value N2 is the sum. When the value is smaller than the value N1, the slave unit 22 [108] is selected as the upper communication terminal. The control unit 101 of the slave unit 20 [115] determines the average value of the first terminal number of the slave unit 22 [107] and the second terminal number of the slave unit 21 [102] and the slave unit 22 [108]. You may select a high-order communication terminal based on the magnitude of the 1st terminal number and the average value of the 2nd terminal number of subunit | mobile_unit 21 [103]. Moreover, the control part 101 of the subunit | mobile_unit 20 [115] may select a high-order communication terminal by comparing the value calculated | required by weighting the 1st terminal number and the 2nd terminal number. For example, when α is a positive coefficient smaller than 1, the control unit 101 of the slave unit 20 [115] sets a value of [(first terminal number) × α + (second terminal number) × (1−α)]. The upper communication terminal may be selected based on this value.

  As described above, the control unit 101 of the communication terminal 100 performs selection processing based on the number of first terminals and the number of second terminals, so that many lower communication terminals are concentratedly connected to a specific upper communication terminal. The possibility that the communication load is concentrated on a specific upper communication terminal can be reduced.

  Note that the number of lower-level terminals of higher-level communication terminals connected to higher ranks of the higher-ranking candidates may be reflected on the route cost (value obtained by digitizing the communication quality of the communication route) that is route quality information of the higher-ranking candidates. In this case, the control unit 101 of the communication terminal 100 may select an upper communication terminal from a plurality of upper candidates based on the number of lower terminals of each upper candidate and the route cost.

  In the above description, the operation when the child device 20 newly enters the communication system 600 has been described. However, the child device 20 that has already entered the communication system 600 is triggered by the entry of another child device 20 or the like. You may perform the selection process which selects a high-order communication terminal.

  The control unit 101 of the communication terminal 100 executes a selection process when a parameter relating to whether or not the upper communication terminal needs to be changed exceeds a determination value. This parameter is, for example, the number of lower terminals of the upper communication terminal of the communication terminal 100. The control unit 101 of the communication terminal 100 executes the selection process with a trigger that the number of lower terminals of the upper communication terminal to which the communication terminal 100 is connected exceeds a predetermined upper limit value (determination value).

  For example, as shown in FIG. 4, when the slave unit 23 [115] is connected to the lower order of the slave unit 22 [108], the number of lower terminals of the slave unit 22 [108], which is the higher order communication terminal, is a predetermined number. When the upper limit is exceeded, the control unit 101 of the slave unit 23 [115] executes a selection process. The control unit 101 of the slave unit 23 [115] periodically acquires H packets from other slave units 20 (higher candidates) capable of direct communication via the communication unit 102, and the terminals included in the H packets Based on the number information, a higher communication terminal is determined from a plurality of higher candidates. The control unit 101 of the slave unit 23 [115] selects the slave unit 20 other than the current higher-level communication terminal (slave unit 22 [108]) as the higher-level communication terminal as a result of the selection process. Entry processing is executed for the slave unit 20. As a result, even when the child device 20 changes the upper communication terminal triggered by the entry of a new child device 20 into the communication system 600, the lower communication terminals are connected to a specific upper candidate. The possibility can be reduced. Therefore, it is possible to reduce the possibility that the communication load is concentrated on a specific superior candidate.

  Further, in the present embodiment, information regarding the number of lower communication terminals is included in the H packet, and each communication terminal 100 (slave device 20) can communicate with another communication terminal 100 (communication unit 102) with which the communication unit 102 can directly communicate. The information on the number of terminals of the lower communication terminals (terminal number information) is shared with the slave unit 20). Therefore, the control unit 101 of each communication terminal 100 can perform selection processing based on the number-of-terminals information shared with other communication terminals 100 with which the communication unit 102 can directly communicate. It is possible to grasp the number of lower communication terminals more accurately.

  Further, in the present embodiment, the H packet received from the upper candidate by the communication unit 102 includes the terminal number information regarding the number of lower communication terminals, and the number of terminals using the H packet instead of the dedicated communication packet. Since information is transmitted, communication traffic can be reduced.

(3) Modifications The above embodiment is only one of various embodiments of the present disclosure. The above embodiment can be variously modified according to the design and the like as long as the object of the present disclosure can be achieved. The functions similar to those of the communication system 600 may be embodied by a communication method, a computer program, a non-transitory recording medium that records the program, or the like. The communication method according to an aspect includes a selection process for selecting a higher communication terminal from a plurality of higher candidates based on the number of lower communication terminals connected to each of the plurality of higher candidates. A program according to an aspect executes a selection process for selecting a higher communication terminal from a plurality of higher candidates based on the number of lower communication terminals connected to each of the plurality of higher candidates in a computer system. It is a program to make it.

  Hereinafter, modifications of the above embodiment will be listed. The modifications described below can be applied in appropriate combinations.

  The execution subject of the communication terminal 100 or the communication method in the present disclosure includes a computer system. The computer system mainly includes a processor and a memory as hardware. When the processor executes the program recorded in the memory of the computer system, a function as an execution subject of the communication terminal 100 or the communication method in the present disclosure is realized. The program may be recorded in advance in the memory of the computer system, but may be provided through an electric communication line, or may be provided by being recorded in a non-transitory recording medium readable by the computer system. Non-transitory recording media readable by the computer system are a memory card, an optical disk, a hard disk drive, and the like. A processor of a computer system includes one or a plurality of electronic circuits including a semiconductor integrated circuit (IC) or a large scale integrated circuit (LSI). Here, it is called IC or LSI, but the name changes depending on the degree of integration, and may be called system LSI, VLSI (very large scale integration), or ULSI (Ultra Large Scale Integration). Field programmable gate arrays (FPGAs) programmed after manufacturing LSIs, or reconfigurable logic devices that can reconfigure junctions inside LSIs or set up circuit partitions inside LSIs can be used in the same way is there. The plurality of electronic circuits may be integrated on one chip, or may be distributed on the plurality of chips. The plurality of chips may be integrated into one device, or may be distributed and provided in a plurality of devices.

  In the above-described embodiment, the communication terminal 100 is realized by one device that fits in one case. However, at least one function of the communication unit 102 and the control unit 101 included in the communication terminal 100 has two functions. The above devices may be provided in a distributed manner.

  In the above embodiment, in the comparison of binary values such as the number of terminals, “greater than” may be “greater than”. That is, in the binary comparison, whether or not the two values are equal can be arbitrarily changed depending on the setting of the reference value or the like, so there is no technical difference between “greater than” or “greater than”. Similarly, “less than” may be “less than”.

(3.1) Modification 1
The communication terminal 100 of Modification 1 is different from the above embodiment in that the control unit 101 performs the selection process based on the communication quality of communication with each of a plurality of higher-order candidates. In addition, since the structure of the communication terminal 100 and the communication system 600 of the modification 1 is the same as that of the said embodiment, the same code | symbol is attached | subjected to the same component and the description is abbreviate | omitted.

  The control unit 101 of the slave unit 20 (communication terminal 100) periodically acquires H packets from the plurality of slave units 20 (communication terminal 100) existing in a range where direct communication is possible via the communication unit 102. Here, the H packet includes terminal number information related to the number of lower communication terminals and route quality information indicating the communication quality of the communication route.

  In the communication terminal 100 according to the first modification, the control unit 101 of the child device 20 performs route selection information obtained from a plurality of child devices 20 that are higher candidates and a predetermined threshold value when performing a selection process for selecting a higher communication terminal. The primary candidate is selected by comparing the heights with. And the control part 101 of the subunit | mobile_unit 20 selects a high-order communication terminal based on the terminal number information regarding the terminal number of a low-order communication terminal from primary candidates.

  For example, as illustrated in FIG. 5, the slave unit 23 [115] includes the slave unit 22 [105], the slave unit 22 [106], the slave unit 22 [107], the slave unit 22 [108], and the slave unit 22 [ 109] will be described. In FIG. 5, the slave unit 22 [105], the slave unit 22 [106], the slave unit 22 [107], the slave unit 22 [108], the slave unit 22 [109], and the slave unit 23 [115] are respectively represented. Next to the link 501 to be connected, an evaluation value indicating communication quality is described. Here, it shows that the communication quality of the link 501 is high, so that the evaluation value described beside the link 501 is small.

  When performing a selection process for selecting a higher-level communication terminal from a plurality of higher-order candidates, the control unit 101 of the child device 23 [115] first has communication quality equal to or higher than a threshold value among the higher-rank candidate handset 20, that is, communication quality. An upper candidate whose evaluation value is less than or equal to a predetermined evaluation reference value is selected as a primary candidate. For example, the control unit 101 of the slave unit 23 [115] has the slave unit 22 [106], the slave unit 22 [107], and the slave unit 22 whose communication quality evaluation value is equal to or less than the evaluation reference value (for example, “10”). [108] is selected as the primary candidate.

  And control part 101 of cordless handset 23 [115] chooses a thing with few terminals of a lower rank communication terminal as a higher rank communication terminal from the primary candidates selected based on communication quality.

  As described above, in the communication terminal 100 according to the first modification, the control unit 101 performs the selection process based further on the communication quality of communication with each of the plurality of high-order candidates. A communication terminal can be selected. Therefore, it is possible to reduce the possibility that a higher candidate having a relatively poor communication quality among the higher candidates is selected as a higher communication terminal.

  Here, in the communication terminal 100 of the first modification, the control unit 101 selects an upper communication terminal based on the number of lower communication terminals from among upper candidates whose communication quality is equal to or higher than a threshold among a plurality of upper candidates. Selected. In other words, in Modification 1, a plurality of high-order candidates are grouped according to communication quality, and a high-order communication terminal is selected from a group of primary candidates whose communication quality is equal to or higher than a threshold among the plurality of high-order candidates. Therefore, it is possible to select a higher candidate whose communication quality is equal to or higher than the threshold as a higher communication terminal while reducing the possibility that many lower communication terminals are concentratedly connected to a specific higher communication terminal.

  In the first modification, the communication quality threshold is not limited to one. The control unit 101 of the communication terminal 100 may lower the threshold stepwise until the higher-level communication terminal can be selected in the selection process.

  For example, in the case where one or a plurality of upper candidates selected as the primary candidates do not have a terminal number of lower communication terminals equal to or lower than a preset upper limit value, the control unit 101 sets a communication quality threshold value. To increase the number of top candidates selected as primary candidates. And the control part 101 selects a high-order communication terminal based on the terminal number of a low-order communication terminal from the high-order candidates selected as a primary candidate. Thereby, the control part 101 of the communication terminal 100 can select the subunit | mobile_unit 20 with the number of terminals of a low-order communication terminal below an upper limit, and favorable communication quality as a high-order communication terminal.

(3.2) Modification 2
In the communication terminal 100 of the above-described embodiment, the control unit 101 executes a selection process when a parameter related to whether or not to change the host communication terminal exceeds a determination value. For example, when the parameter related to whether or not the upper communication terminal needs to be changed is the deterioration degree of the communication quality, when the deterioration degree of the communication quality exceeds the determination value, the control unit 101 executes a change process for changing the upper communication terminal.

  Here, when the number of lower communication terminals connected to the own terminal exceeds the reference number, the number of lower communication terminals connected to the own terminal is equal to or less than the reference number. Compared with the above-described embodiment, it is different from the above-described embodiment in that the determination value is increased. In addition, since the structure of the communication terminal 100 and the communication system 600 of the modification 2 is the same as that of the said embodiment, the same code | symbol is attached | subjected to the same component and the description is abbreviate | omitted.

  When the handset 20 whose number of lower communication terminals exceeds the reference number changes the upper communication terminal, the number of lower terminals of the change destination higher communication terminal greatly fluctuates. There is a possibility that the communication load is concentrated on the network.

  Therefore, in the communication terminal 100 of the second modification, the control unit 101 increases the determination value when the number of lower terminals of the own terminal exceeds the reference number compared to the case where the number of lower terminals of the own terminal is equal to or less than the reference number. This makes it difficult for the host communication terminal selection process to be executed. Therefore, the communication terminal 100 whose number of lower-level communication terminals exceeds the reference number can reduce the influence on other communication terminals 100 by changing the higher-level communication terminal.

  The control unit 101 of the communication terminal 100 determines that the number of hops of the lower communication terminal connected to the own terminal is the maximum when the number of hops of the lower communication terminal connected to the own terminal matches the maximum hop number. The above determination value may be made higher than when the number of hops is smaller. Here, the maximum number of hops is an upper limit value of the number of hops allowed in the communication system 600 and is a value determined according to the system configuration of the communication system 600 and the like.

  When the control unit 101 of the communication terminal 100 increases the determination value when the number of hops of the lower communication terminal connected to the own terminal matches the maximum number of hops, compared to the case where the number is smaller than the maximum number of hops, It becomes difficult for the host communication terminal selection process to be executed. Therefore, when the communication terminal 100 changes the upper communication terminal, it becomes difficult to change the hop number of the lower communication terminal connected to the lower level of the communication terminal 100, and the hop number of the lower communication terminal exceeds the maximum hop number. The possibility can be reduced.

(3.3) Modification 3
The communication terminal 100 of Modification 3 is different from the above embodiment in the content of the selection process performed by the control unit 101 of each communication terminal 100. In addition, since the structure of the communication terminal 100 of the modification 3 and the communication system 600 is the same as that of the said embodiment, the same code | symbol is attached | subjected to the same component and the description is abbreviate | omitted.

  For example, as shown in FIG. 6, when a plurality of (for example, 10) slave units 23 (23 [201], 23 [202],... 23 [210]) are turned on all at once, The operation when the slave unit 23 enters the communication system 600 all at once will be described.

  When each child device 23 performs a selection process for selecting a higher-level communication terminal, the control unit 101 of each child device 23 selects each of the child devices 22 [107] and 22 [108] that are a plurality of higher-order candidates. A selection process is further performed based on the probability. For example, the control unit 101 of each slave unit 23 selects the selection probability based on the reciprocal of the route communication quality of the slave units 22 [107] and 22 [108] based on the route quality information (route cost, etc.) included in the H packet. Set as. As a result, among the plurality of high-order candidates, the high-order candidate having a lower route cost has a higher selection probability. Therefore, the control unit 101 of each slave unit 23 selects one of the slave units 22 [107] and 22 [108] as a higher-level communication terminal according to the selection probability, so that a plurality of slave units 23 are selected as higher-level communication candidates. The slave 20 to be distributed is distributed according to the selection probability. Therefore, it is possible to reduce the possibility that a specific superior candidate is selected as the superior communication terminal.

  In the third modification, the control unit 101 of each slave unit 23 (communication terminal 100) has a predetermined waiting time from the timing at which an event (for example, power-on) that triggers the selection process of the host communication terminal occurs. The selection process may be executed after elapse of time. The event that triggers the selection process is not limited to the communication terminal 100 being turned on. For example, the communication quality of communication with the upper communication terminal is deteriorated, or communication with the upper communication terminal is impossible. It may be that.

  When the control unit 101 of each slave unit 23 executes the selection process at the same timing, the control unit 101 of each slave unit 23 may select the same slave unit 22 [107], thereby causing the selection process to be performed again. In order to execute, it may take time to determine the upper communication terminal.

  Here, if the above-mentioned waiting time is set to a different time for each of the plurality of slave units 23, the timing at which the control unit 101 of each slave unit 23 executes the selection process is distributed. The time until the control unit 101 determines the upper communication terminal can be shortened.

  Note that the control unit 101 of the plurality of slave units 23 performs selection processing to determine the upper communication terminal, and then reconfirms the number of lower terminals of the change destination upper communication terminal, and determines the upper candidate determined as the upper communication terminal. It may be determined again whether or not to enter the process. As a result, the control unit 101 of each slave unit 23 can perform the entry process to the upper candidate determined as the higher communication terminal after confirming the number of lower terminals immediately before executing the entry process. It is possible to reduce the possibility that the communication terminal 100 is connected to the lower order of the higher order communication terminals.

  Here, the waiting time is preferably set based on a difference in communication quality with the selected higher-level communication terminal and communication quality with the higher-level communication terminal that is the switching destination.

  For example, the control unit 101 of each slave unit 23 increases the waiting time as the difference between the communication quality with the selected upper communication terminal and the communication quality of the switching destination higher communication terminal when the higher communication terminal is switched is smaller. A short time may be set. As a result, the slave unit 23 whose communication quality does not change much even when the host communication terminal is changed switches the host communication terminal early. Therefore, the slave unit 23 whose communication quality deteriorates by changing the host communication terminal There is no need to change the communication terminal. As a result, in the entire communication system 600, each slave unit 23 (communication terminal 100) can select the communication terminal 100 with good communication quality as the upper communication terminal.

  In addition, when communication quality changes greatly by changing a higher-level communication terminal, the slave unit 23 that changes in a direction in which the communication quality is improved may set the waiting time to a short time, and communication with good communication quality. The terminal 100 can be selected as the upper communication terminal.

(3.4) Modification 4
In the above embodiment, the upper candidate lower communication terminals are communication terminals that are connected to the lower of the upper candidates and that can communicate directly with the upper candidates. Communication terminal. For example, in the configuration example of FIG. 1, the lower-level communication terminal of the child device 22 [106] includes the child device 23 [111] and the child device 23 [112], and the child device connected to the child device 23 [111]. 24 [120].

  The control unit 101 of each slave unit 20 (communication terminal 100), based on the number of lower communication terminals connected to each of a plurality of higher candidates, that is, the number of all communication terminals connected to the lower of the higher candidates, An upper communication terminal is selected from a plurality of upper candidates. Therefore, the control unit 101 of each child device 20 can select the upper communication terminal in consideration of the number of all lower communication terminals connected to the lower of the upper candidates, and the specific upper candidate is the upper The possibility of being selected as a communication terminal can be reduced.

(Summary)
As described above, the communication terminal (100) of the first aspect is the communication terminal (100) of the communication system (600) in which the plurality of communication terminals (100) perform multi-hop communication. The communication terminal (100) includes a communication unit (102) and a control unit (101) that controls the communication unit (102). Based on the number of terminals of the lower communication terminal (100) connected to each of the plurality of upper candidates (100), the control unit (101) selects the upper communication terminal (100) from among the plurality of upper candidates (100). A selection process for selecting is performed.

  According to this aspect, since the control unit (101) selects the upper communication terminal (100) from among the plurality of upper candidates (100) based on the number of terminals of the lower communication terminal (100), The possibility that the upper candidate (100) is selected as the upper communication terminal (100) can be reduced.

  In the communication terminal (100) of the second aspect, in the first aspect, the lower communication terminal (100) is a communication terminal (100) with which the upper candidate (100) can directly communicate.

  According to this aspect, it is possible to reduce the possibility that a specific upper candidate (100) is selected as the upper communication terminal (100).

  In the communication terminal (100) of the third aspect, in the first aspect, the lower communication terminals (100) are all communication terminals (100) connected to the lower rank of the upper candidate (100).

  According to this aspect, it is possible to reduce the possibility that a specific upper candidate (100) is selected as the upper communication terminal (100).

  In the communication terminal (100) of the fourth aspect, in any one of the first to third aspects, the control unit (101) is further based on the communication quality of communication with each of the plurality of high-order candidates (100). To perform the selection process.

  According to this aspect, it is possible to select the high-order candidate (100) with good communication quality as the high-order communication terminal (100).

  In the communication terminal (100) of the fifth aspect, in any one of the first to fourth aspects, the control unit (101) is based on the number of terminals of the lower communication terminal (100) from among predetermined candidates. Then, the upper communication terminal (100) is selected. The predetermined candidate is an upper candidate (100) whose communication quality is equal to or higher than a threshold among the plurality of upper candidates (100).

  According to this aspect, it is possible to select the high-order candidate (100) with good communication quality as the high-order communication terminal (100).

  In the communication terminal (100) according to the sixth aspect, in the fifth aspect, the control unit (101) lowers the threshold stepwise until the upper communication terminal (100) can be selected in the selection process.

  According to this aspect, it is possible to select the high-order candidate (100) with good communication quality as the high-order communication terminal (100).

  In the communication terminal (100) according to the seventh aspect, in any one of the first to sixth aspects, the lower communication terminal can communicate with another communication terminal (100) with which the communication unit (102) can directly communicate. The terminal number information regarding the terminal number of (100) is shared.

  According to this aspect, since the terminal number information is shared with the other communication terminal (100) with which the communication unit (102) can directly communicate, the terminal of the lower communication terminal (100) of the upper candidate (100) The number can be grasped more accurately.

  In the communication terminal (100) according to the eighth aspect, in the seventh aspect, the number-of-terminals information is included in the hello packet that the communication unit (102) receives from the top candidate (100).

  According to this aspect, communication traffic can be reduced as compared with the case where terminal number information is transmitted using a dedicated communication packet.

  In the communication terminal (100) according to the ninth aspect, in any one of the first to eighth aspects, the control unit (101) has a parameter regarding whether or not the upper communication terminal (100) needs to be changed exceeds a determination value. And execute the selection process. When the number of lower communication terminals (100) connected to the own terminal (100) exceeds the reference number, the control unit (101) moves the lower communication terminal (100) connected to the own terminal (100). The determination value is increased compared to the case where the number of terminals is equal to or less than the reference number.

  According to this aspect, the communication terminal (100) in which the number of terminals of the lower communication terminals (100) exceeds the reference number becomes difficult to perform the selection process. ) Can be changed to reduce the influence on other communication terminals (100).

  In the communication terminal (100) of the tenth aspect, in any one of the first to eighth aspects, the control unit (101) has a parameter related to necessity of change of the host communication terminal (100) exceeding a determination value. And execute the selection process. When the number of hops of the lower communication terminal (100) connected to the own terminal (100) matches the maximum number of hops, the control unit (101) is connected to the lower terminal (100). The determination value is made higher than when the (100) hop count is smaller than the maximum hop count.

  According to this aspect, when the communication terminal (100) changes the upper communication terminal (100), the possibility that the number of hops of the lower communication terminal (100) exceeds the maximum number of hops can be reduced.

  In the communication terminal (100) of the eleventh aspect, when the number of communication terminals (100) constituting the communication system (600) is changed in any one of the first to tenth aspects, the control unit (101 ) Performs a selection process. A control part (101) performs a selection process further based on the selection probability set to each of a some high-order candidate (100).

  According to this aspect, by performing the selection process based on the selection probability, it is possible to reduce the possibility that the specific upper candidate (100) is selected as the upper communication terminal (100).

  In the communication terminal (100) according to the twelfth aspect, in any one of the first to eleventh aspects, the control unit (101) waits for a waiting time from the timing when the event that triggers the selection process occurs. After that, the selection process is executed.

  According to this aspect, by shifting the timing for performing the selection process, it is possible to reduce the possibility that the specific upper candidate (100) is selected as the upper communication terminal (100).

  In the communication terminal (100) of the thirteenth aspect, in the twelfth aspect, the waiting time is the communication quality with the selected upper communication terminal (100) and the communication quality with the switching destination upper communication terminal (100). Is set based on the difference between

  According to this aspect, for example, if the waiting time is shortened as the communication terminal (100) having a smaller difference in communication quality before and after changing the upper communication terminal (100), the communication terminal (100) has a difference in communication quality. Can be selected as the higher communication terminal (100). Therefore, the high-order candidate (100) having good communication quality in the entire communication system (600) can be selected as the high-order communication terminal (100).

  The communication system (600) according to the fourteenth aspect includes a plurality of communication terminals (100) according to any one of the first to thirteenth aspects, and performs multi-hop communication between the plurality of communication terminals (100).

  According to this aspect, it is possible to reduce the possibility that a specific upper candidate (100) is selected as the upper communication terminal (100).

  The program according to the fifteenth aspect is a computer system in which a higher rank is selected from a plurality of higher rank candidates (100) based on the number of lower rank communication terminals (100) connected to each of the multiple higher rank candidates (100). A selection process for selecting the communication terminal (100) is executed.

  According to this aspect, it is possible to reduce the possibility that a specific upper candidate (100) is selected as the upper communication terminal (100).

  Various configurations (including modifications) of the communication terminal (100) according to the above-described embodiment are not limited to the above-described embodiments, and may be embodied by a communication method, a (computer) program, a non-temporary recording medium storing the program, or the like. Is possible.

  The configurations according to the second to thirteenth aspects are not essential to the communication terminal (100) and can be omitted as appropriate.

100 communication terminals (higher candidates, higher communication terminals, lower communication terminals)
101 control unit 102 communication unit 600 communication system

Claims (15)

The communication terminal of a communication system in which a plurality of communication terminals perform multi-hop communication,
A communication department;
A control unit for controlling the communication unit,
The control unit performs a selection process of selecting a higher communication terminal from the plurality of higher candidates based on the number of lower communication terminals connected to each of the plurality of higher candidates.
Communication terminal. The lower communication terminal is a communication terminal with which the upper candidate can directly communicate.
The communication terminal according to claim 1. The lower communication terminals are all communication terminals connected to the lower rank of the upper candidates.
The communication terminal according to claim 1. The control unit performs the selection process based on communication quality of communication with each of the plurality of upper candidates.
The communication terminal according to any one of claims 1 to 3. The control unit selects the upper communication terminal based on the number of the lower communication terminals from among the upper candidates whose communication quality is equal to or higher than a threshold value among the plurality of upper candidates.
The communication terminal of any one of Claims 1-4. The control unit lowers the threshold stepwise until the higher order communication terminal can be selected in the selection process.
The communication terminal according to claim 5. Sharing the number-of-terminals information regarding the number of the lower communication terminals with other communication terminals with which the communication unit can directly communicate,
The communication terminal of any one of Claims 1-6. The hello packet that the communication unit receives from the top candidates includes the terminal number information.
The communication terminal according to claim 7. The control unit executes the selection process when a parameter related to necessity of change of the host communication terminal exceeds a determination value,
The control unit, when the number of the lower communication terminals connected to the own terminal exceeds a reference number, the number of the lower communication terminals connected to the own terminal is equal to or less than the reference number. Compared to the case, increase the judgment value,
The communication terminal of any one of Claims 1-8. The control unit executes the selection process when a parameter related to necessity of change of the host communication terminal exceeds a determination value,
When the hop number of the lower communication terminal connected to the own terminal matches the maximum hop number, the control unit determines that the hop number of the lower communication terminal connected to the own terminal is the maximum hop number. The judgment value is increased as compared with the case where it is smaller than
The communication terminal of any one of Claims 1-8. The control unit performs the selection process based further on a selection probability set for each of the plurality of top candidates.
The communication terminal of any one of Claims 1-10. The control unit executes the selection process after a waiting time has elapsed from the timing at which an event that triggers the selection process occurs.
The communication terminal of any one of Claims 1-11. The waiting time is set based on the difference between the communication quality with the selected higher-order communication terminal and the communication quality with the higher-order communication terminal that is the switching destination.
The communication terminal according to claim 12. A plurality of communication terminals according to any one of claims 1 to 13,
Performing multi-hop communication between the plurality of communication terminals,
Communications system. Computer system,
A program for executing a selection process for selecting an upper communication terminal from the plurality of upper candidates based on the number of lower communication terminals connected to each of the plurality of upper candidates.

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