JP2013214824A - Communication apparatus, communication system, switching control method, and switching control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication apparatus or the like capable of regulating the number of connected units of each GW.SOLUTION: A communication unit 5 includes: a radio communication section 61 wirelessly connecting with an accommodated GW7A and capable of wirelessly connecting with an accommodation candidate GW7B; a collection section 68A for collecting the number of connected units at the accommodated GW7A side and the number of connected units at the accommodation candidate GW7B side. The communication unit 5 includes a calculation section 68B that calculates the number of the units to be moved of the communication unit 5 which are to be moved from the accommodated GW7A to the accommodation candidate GW7B on the basis of a difference between the number of the connected units of the accommodated GW7A side and the number of the connected units of the accommodation candidate GW7B side, both numbers being collected. The communication unit 5 includes a determination section 68C that determines whether corresponding to the unit to be moved on the basis of the number of units to be moved, the number of connected units of the accommodated GW7A side, and random numbers. The communication unit 5 further includes a switching control section 68D that requests switching connection from the accommodated GW7A to the accommodation candidate GW7B to the accommodation candidate GW7B when corresponding to the unit to be moved.

Description

  The present invention relates to a communication device, a communication system, a switching control method, and a switching control program.

  2. Description of the Related Art In recent years, autonomous multi-hop communication systems are widely known in which each communication unit autonomously performs routing and wirelessly transmits data using a multi-hop method. In an autonomous multi-hop communication system, each communication unit periodically updates route information by exchanging route information with an adjacent unit connected in one hop. Each communication unit transmits data by relaying one or a plurality of communication units from the transmission source communication unit to the final destination communication unit based on the updated path information.

  The autonomous multi-hop communication system includes a communication unit, a relay unit, and a gateway (hereinafter simply referred to as GW). The GW is connected to a wired network and accommodates an arbitrary communication unit or relay unit in an autonomous multi-hop communication system. Further, the autonomous multi-hop system includes a plurality of GWs so as to be connected to the wired network in a redundant configuration.

  Each communication unit includes route information addressed to a plurality of GWs. The route information includes an evaluation value indicating the priority of the route of each GW. Each communication unit has a main GW that is used for normal operation and a sub GW that is used when the main GW fails or the main GW is switched based on the evaluation value in the route information.

  The GW, the communication unit, and the relay unit update the evaluation value in the route information in accordance with the radio wave quality of the Hello frame and the success record of data transmission. For example, the GW, the communication unit, and the relay unit regularly exchange Hello frames with adjacent units. Then, the GW, the communication unit, and the relay unit generate a link table and a routing table based on the route information in the exchanged frame. The link table manages addresses and communication quality of adjacent units. In addition, the routing table manages an evaluation value related to the relay destination adjacent unit and the route of the adjacent unit for each final destination unit. The GW, the communication unit, and the relay unit transmit data to the destination unit via the relay destination having a good evaluation value based on the evaluation value in the routing table.

  In addition, the GW, the communication unit, and the relay unit update the evaluation value in the routing table according to the radio wave quality at the time of receiving the Hello frame and the successful record of data transmission. The evaluation value increases according to the number of successful data transmissions.

JP 2005-79827 A JP 2004-350052 A JP 2009-267532 A JP 2011-9967 A JP 2011-9969 A

  In a conventional communication system, each communication unit is sequentially connected to an adjacent GW in response to power-on of each communication unit. However, even though a plurality of GWs are arranged in the periphery, for example, connections are concentrated on one GW, and the number of communication units connected is biased. As a result, for example, when wireless communication is concentrated on GWs in which the number of connected devices is biased, wireless congestion occurs.

  Further, in the GW, even when a new communication unit is arranged in the vicinity of the GW when there is no space in the table for managing the path information of the communication units to be connected due to the uneven number of connected devices, the new communication unit Route information cannot be registered.

  Also, the GW can switch all communication units connected to the other GW after failure due to failure, maintenance, etc., but since all are GW-initiated processing, a processing load is imposed on the GW itself.

  In one side, it aims at providing the communication apparatus etc. which can adjust the number of connection of each GW.

  The aspect of the disclosure includes a communication unit that is communicably connected to the accommodated communication accommodation device and is communicably connected to the accommodation candidate communication accommodation device. Furthermore, the disclosed aspect collects the number of connected communication devices to which the accommodated communication accommodation device communicates from the accommodated communication accommodation device, and communicates the accommodation candidate from the accommodation candidate communication accommodation device. A collection unit that collects the number of connected communication devices connected to the device. The aspect of the disclosure is based on the difference between the collected number of connections on the side of the accommodated communication accommodation device and the number of connections on the communication accommodation device side of the accommodation candidate, and communication of the accommodation candidate from the accommodated communication accommodation device A calculation unit that calculates the number of movement target communication devices that move to the accommodation device; Furthermore, the aspect of an indication has the determination part which determines whether it corresponds to the said movement object based on the said movement object number, the number of the connection by the side of the said communication accommodation apparatus currently accommodated, and a random number. Furthermore, the aspect of an indication has a control part which requests | requires the switching connection from the communication accommodation apparatus currently accommodated to the communication accommodation apparatus of the said accommodation candidate to the said communication accommodation apparatus of the accommodation candidate, when it corresponds to the said movement object. .

  In the disclosed aspect, the number of connected communication accommodation devices can be adjusted by an autonomous operation on the communication device side connected to the communication accommodation device.

FIG. 1 is an explanatory diagram illustrating an example of a communication system according to this embodiment. FIG. 2 is a block diagram illustrating an example of a hardware configuration of the GW. FIG. 3 is a block diagram illustrating an example of a functional configuration of the GW. FIG. 4 is an explanatory diagram illustrating an example of a table configuration of the link table. FIG. 5 is an explanatory diagram illustrating an example of a table configuration (LD1 to LD3) of the routing table. FIG. 6 is an explanatory diagram illustrating an example of a table configuration of the frame transfer table. FIG. 7 is an explanatory diagram illustrating an example of a Hello frame. FIG. 8 is a block diagram illustrating an example of a hardware configuration of the communication unit. FIG. 9 is a block diagram illustrating an example of a functional configuration of the communication unit. FIG. 10 is an explanatory diagram illustrating an example of updating the link table and the routing table. FIG. 11 is an explanatory diagram illustrating an example of updating the link table and the routing table. FIG. 12 is an explanatory diagram illustrating an example of use of the routing table. FIG. 13 is an explanatory diagram showing an example of updating the routing table. FIG. 14 is a flowchart illustrating an example of the processing operation of the processor on the communication unit side involved in the GW switching selection process. FIG. 15 is an explanatory diagram illustrating an example of convergence of the number of connected GWs being accommodated and accommodation candidates GW. FIG. 16A is an explanatory diagram illustrating an example of the convergence transition of the number of connected units simulated by the determination algorithm 1. FIG. 16B is an explanatory diagram illustrating an example of the convergence transition of the number of connected units simulated by the determination algorithm 2. FIG. 16C is an explanatory diagram illustrating an example of the convergence transition of the number of connected units simulated by the determination algorithm 3. FIG. 16D is an explanatory diagram illustrating an example of the convergence transition of the number of connected units simulated by the determination algorithm 4. FIG. 17 is an explanatory diagram illustrating an example of a communication device that executes a switching control program.

  Hereinafter, embodiments of a communication device, a communication system, a switching control method, and a switching control program disclosed in the present application will be described in detail based on the drawings. The disclosed technology is not limited by the present embodiment.

  FIG. 1 is an explanatory diagram illustrating an example of a communication system according to this embodiment. A communication system 1 shown in FIG. 1 includes a wired network system (hereinafter simply referred to as a wired system) 2 and a multi-hop network system (hereinafter simply referred to as a multi-hop system) 3. The wired system 2 includes a server 4 that is constructed by, for example, a WAN (Wide Area Network) and monitors the entire communication system 1. The multi-hop system 3 is constructed by an autonomous multi-hop ad hoc communication network, and includes a communication unit 5, a relay unit 6, and a gateway (hereinafter simply referred to as GW) 7. The communication unit 5 and the relay unit 6 are communication devices.

  The communication unit 5, the relay unit 6, and the GW 7 transmit data by autonomous multi-hop wireless communication. The GW 7 communicates with the communication unit 5 and the relay unit 6 in the multi-hop system 3 by an autonomous multi-hop wireless method, and communicates with the server 4 in the wired system 2 by wire.

  The communication system 1 shown in FIG. 1 is a system that collects and manages the amount of power in the home on the server 4 side, for example. The communication unit 5 is, for example, a unit that is connected to a power meter (not shown) disposed in the home. And the server 4 collects electric energy from the wattmeter arrange | positioned in each household through the communication unit 5, and manages the collected electric energy in the household. Each communication unit 5 periodically transmits the amount of power collected from the power meter to the server 4 via the GW 7. Further, for example, the server 4 transmits control data for controlling the communication unit 5 to each communication unit 5 via the GW 7. In addition, since the power meter in this system is fixedly arranged in the home, for example, the communication unit 5 is also fixedly arranged.

  FIG. 2 is a block diagram illustrating an example of a hardware configuration of the GW 7. The GW 7 illustrated in FIG. 2 includes a network interface 11, a wireless interface 12, an auxiliary storage device 13, a memory 14, and a processor 15. The network interface 11 is a communication interface connected to the wired system 2. The wireless interface 12 is an interface connected to the multihop system 3. The auxiliary storage device 13 is, for example, a flash memory that stores various types of information related to route information such as a routing table and a link table described later. The memory 14 stores various information of various programs. The processor 15 controls the entire GW 7.

  FIG. 3 is a block diagram illustrating an example of a functional configuration of the GW 7. The processor 15 configures functions that become various processes based on a program stored in the memory 14. 3 includes a network communication unit 21, a radio communication unit 22, a frame analysis unit 23, a data generation unit 24, a data acquisition unit 25, a setting information acquisition unit 26, and a GW information generation unit 27. The path control unit 28, the storage unit 29, and the control unit 30 function. The network communication unit 21 controls wired communication with the wired system 2 through the network interface 11. The wireless communication unit 22 controls wireless communication with the multihop system 3 through the wireless interface 12.

  The frame analysis unit 23 analyzes the frames of the communication unit 5, the relay unit 6, and the GW 7 in the multihop system 3 through the wireless interface 12. The data generation unit 24 generates data. The data acquisition unit 25 acquires data. The setting information acquisition unit 26 acquires setting information. The path control unit 28 controls an autonomous multi-hop communication path. The GW information generation unit 27 generates GW information including the load of the GW 7, for example, the number of accommodation units and the amount of transfer traffic. The storage unit 29 manages various tables such as a link table 31, a routing table 32, and a frame transfer table 33 described later. The control unit 30 periodically notifies the communication unit 5 and the relay unit 6 of the number of accommodation units accommodated by the own GW 7, that is, the number of connected units, through the wireless communication unit 22.

  FIG. 4 is an explanatory diagram showing an example of the table configuration of the link table 31. The link table 31 shown in FIG. 4 manages the return path weight value 31B, the forward path weight value 31C, and the bidirectional weight value 31D for each adjacent transmission source (LS) 31A. The adjacent transmission source (LS) is the IP / MAC address of the adjacent unit that transmitted the Hello frame. The return path weight value 31B is a value related to the signal quality of the return path with the adjacent transmission source (LS). The forward path weight value 31C is a value related to the signal quality of the forward path with the adjacent transmission source (LS). The bidirectional weight value 31D is a value related to bidirectional signal quality between adjacent transmission sources (LS).

  FIG. 5 is an explanatory diagram illustrating an example of a table configuration of the routing table 32. The routing table 32 shown in FIG. 5 manages an adjacent destination (LD) 32B and an evaluation value 32C for each final destination (GD: Global Destination) 32A. The final destination 32A is the IP / MAC address of the final destination of data. The adjacent destination 32B is an IP / MAC address of an adjacent unit that relays when transmitting data to the final destination. The evaluation value 32C is used to determine the priority of a route through which data is relayed. The evaluation value 32C has a higher evaluation and a higher priority as the numerical value becomes smaller. The routing table 32 manages, for each final destination 32A, a priority, for example, first to third adjacent destinations (LD1 to LD3) 32B and an evaluation value 32C for each adjacent destination 32B.

  FIG. 6 is an explanatory diagram showing an example of the table configuration of the frame transfer table 33. The frame transfer table 33 shown in FIG. 6 manages a transmission source (GS) 33B, a flag 33C, and an adjacent transmission source (LS) 33D for each transfer frame identification information (FID: Frame Identification) 33A. is there. Further, the frame transfer table 33 manages the adjacent destination 1 (LD1) 33E, the adjacent destination 2 (LD2) 33F, the adjacent destination 3 (LD3) 33G, and the latest adjacent destination (LAST) 33H for each FID 33A. The FID 33A is an ID for identifying a transfer frame. The transmission source (GS) 33B is an IP / MAC address that identifies the transmission frame transmission source. The flag 33C is a count value obtained by trying transfer of a transfer frame.

  The adjacent transmission source (LS) 33D is the IP / MAC address of the transmission source adjacent unit that relayed the transfer frame. The adjacent destination 1 (LD1) 33E is the IP / MAC address of the adjacent destination unit with the first priority used when transferring the transfer frame to the final destination. The adjacent destination 2 (LD2) 33F is the IP / MAC address of the adjacent destination unit with the second highest priority used when transferring the transfer frame to the final destination. The adjacent destination 3 (LD3) 33G is the IP / MAC address of the adjacent destination unit with the third highest priority used when transferring the transfer frame to the final destination. The latest adjacent destination 33H is the IP / MAC address of the adjacent destination unit used last when the transfer frame is transferred to the final destination. The latest adjacent destination 33H is, for example, any one of the adjacent destinations (LD1 to LD3).

  The control unit 30 of the GW 7 adds the number of GW arrival hops and the number of connected devices in the Hello frame. FIG. 7 is an explanatory diagram illustrating an example of a configuration of a Hello frame. A Hello frame 90 illustrated in FIG. 7 includes a PHY header 91, a MAC (Media Access Control Access) header 92, an IP (Internet Protocol) header 93, and a UDP (User Data Program) header 94. The Hello frame 90 includes an ad hoc header 95, a payload 96, and an FCS (Frame Check Sequence) 97. The PHY header 91 is a physical layer address. The MAC header 92 is an address of the data link layer. The IP header 93 is a network layer address. The UDP header 94 is a transport layer address. The ad hoc header 95 is an ad hoc communication header.

  The ad hoc header 95 has a packet length 95A, a sequence number 95B, a type 95C, a TTL (Time to Live) 95D, and a hop number 95E. The packet length 95A indicates the length of the packet in the payload. The sequence number 95B is information for identifying a connection. TTL95D indicates the valid period of the packet. Type 95C identifies a data frame or a Hello frame.

  In the payload 96, a GW arrival hop count 96A and a connection count 96B are added. The GW arrival hop count 96A is the number of hops from the communication unit 5 that has received the Hello frame to the GW 7 that has transmitted the Hello frame. Furthermore, the number of connected units 96B is the number of connected communication units 5 and the like accommodated by the GW 7 that has transmitted the Hello frame. Note that when the communication unit 5 receives the Hello frame from the GW 7, the communication unit 5 collects the connection number 96 </ b> B and the GW arrival hop number 96 </ b> A in the payload 96. Then, when there is an adjacent destination, the communication unit 5 updates the number of GW arrival hops 96A in the payload 96 by +1. Then, the communication unit 5 adds the updated GW arrival hop count 96 </ b> A and the connected number 96 </ b> B to the Hello frame, and transmits the Hello frame to the next adjacent destination unit 5. Then, when there is an adjacent destination, each communication unit 5 sequentially transmits a Hello frame to the next adjacent destination while updating the GW arrival hop count 96A. As a result, the GW 7 can transmit a Hello frame including the number of connected units 96 </ b> B up to the terminal communication unit 5.

  FIG. 8 is a block diagram illustrating an example of a hardware configuration of the communication unit 5. The communication unit 5 illustrated in FIG. 8 includes an external device input unit 51, a wireless interface 52, an auxiliary storage device 53, a memory 54, and a processor 55. The external device input unit 51 is an interface connected to an external device such as a power meter that measures the amount of power. The wireless interface 52 is an interface that is wirelessly connected to the multi-hop system 3. The auxiliary storage device 53 is a flash memory that stores various types of information. The memory 54 is a memory that stores information on various programs such as a switching control program. The processor 55 controls the entire communication unit 5. Note that the hardware configuration of the relay unit 6 is substantially the same as that of the communication unit 5 shown in FIG. 8, for example, excluding the external device input unit 51.

  FIG. 9 is a block diagram illustrating an example of a functional configuration of the communication unit 5. The processor 55 shown in FIG. 9 configures functions serving as various processes based on a program stored in the memory 54. 9 includes a wireless communication unit 61, a frame analysis unit 62, a data generation unit 63, a data acquisition unit 64, a setting information acquisition unit 65, a route control unit 66, a storage unit 67, The control unit 68 functions. The wireless communication unit 61 controls wireless communication with the multihop system 3 through the wireless interface 52.

  The frame analysis unit 62 analyzes the frames of the GW 7, the communication unit 5, and the relay unit 6 in the multihop system 3 through the wireless interface 52. The data generation unit 63 generates data. The data acquisition unit 64 acquires data. The setting information acquisition unit 65 acquires setting information. The route control unit 66 controls an autonomous multi-hop communication route. The route controller 66 refers to the routing table 32 and relays the data of the final destination by the unit of the first adjacent destination (LD1) of the final destination 32A. The storage unit 67 manages the link table 31 shown in FIG. 4, the routing table 32 shown in FIG. 5, and the frame transfer table 33 shown in FIG. The storage unit 67 manages the IP / MAC address of the main GW 7 in the main GW address area and the IP / MAC address of the sub GW 7 in association with the sub GW address area. The main GW 7 is a GW 7 that is used by the communication unit 5 during operation, and the secondary GW 7 is, for example, a GW 7 that is used when the main GW 7 fails or is maintained.

  The control unit 68 includes a collection unit 68A, a calculation unit 68B, a determination unit 68C, and a switching control unit 68D. The collection unit 68A periodically receives a Hello frame from the surrounding GW 7 including the GW 7A being accommodated, for example, through the wireless communication unit 61. The Hello frame is transmitted from each GW 7 with a period of, for example, 10 minutes. Then, the collection unit 68A periodically collects the number of connections 96B and the number of GW arrival hops 96A in the received Hello frame. Furthermore, for example, when the GW arrival hop count 96A is within the allowable range as the accommodation destination, the collection unit 68A determines that the GW 7 that has transmitted the Hello frame to which the GW arrival hop count 96A is added is the accommodation candidate GW 7B. Note that the accommodating GW 7A includes, for example, the GW 7 to which the communication unit 5 is wirelessly connected. Further, the accommodation candidate GW 7B is, for example, an unconnected GW 7 that can be wirelessly connected to the communication unit 5, and includes a GW 7 that can be switched and connected from the accommodated GW 7A.

  The calculating unit 68B calculates a difference (GW1−GW2) obtained by subtracting the connected number GW2 of the accommodation candidate GW7B from the connected number GW1 of the accommodated GW7A. When the difference (GW1−GW2) exceeds the difference threshold L, the calculation unit 68B multiplies the difference (GW1−GW2) by a coefficient k equal to or less than an integer “1” to move from the main GW 7A to the sub GW 7B. The movement target number T of the communication units 5 is calculated. The number of movement targets is T = (GW1-GW2) × k. For example, it is assumed that the number of connected GWs 7A connected is 600, the number of connected candidates GW7B is 100 connected, the coefficient k is 0.1, and the difference threshold L is 200. In this case, since the difference (600-100) exceeds the difference threshold L, the calculation unit 68B has the number T of movement targets of (600-100) × 0.1 = 50.

  The determination unit 68C determines whether or not the own unit corresponds to the movement target based on the movement target number T, the number of connected GWs 7A connected (GW1), and the random number. The movement target is the communication unit 5 to be moved that is switched from the accommodating GW 7A to the accommodating candidate GW 7B. That is, the determination unit 68C determines whether or not it corresponds to 50 (moving target) moving targets from 600 (GW1) in the accommodating GW 7A.

  The determination algorithm of the determination unit 68 </ b> C is an algorithm for determining whether or not the object corresponds to the movement target when the difference (GW1−GW2) is equal to or greater than the difference threshold L. The determination algorithm is, for example, IF ((GW1-GW2)> L) {T = INT ((GW1-GW2) * k) P = Int (GW1 * Rnd () + 1) IF (P <= T) { Move target} else {not move target}}.

  When the own unit corresponds to the movement target, the switching control unit 68D switches from the accommodating GW 7A to the accommodating candidate GW 7B and connects them. That is, the switching control unit 68D requests connection to the accommodating candidate GW 7B and requests disconnection from the accommodating GW 7A. Then, the switching control unit 68D updates the storage unit 67 by registering the IP / MAC address of the accommodating candidate GW 7B in the main GW address area and the IP / MAC address of the accommodating GW 7A in the sub GW address area. As a result, the switching control unit 68D has completed switching from the accommodating GW 7A to the accommodating candidate GW 7B.

  FIG. 10 is an explanatory diagram illustrating an example of updating the link table 31 and the routing table 32. For convenience of explanation, the communication unit 5B periodically wirelessly transmits a Hello frame within its own wireless area. The units in the wireless area, for example, the GW 7A, the communication units 5C and 5F receive the Hello frame from the communication unit 5B. As a result, the communication unit 5 calculates the weight value 31B of the return path with the unit that transmitted the Hello frame, based on the RSSI when the Hello frame is received. RSSI is greatly influenced by the wireless environment.

  For example, the communication unit 5C that has received the Hello frame generates the link table 31 in which the LS 31A is “5B” and the return path weight value 31B is “20”. Further, the communication unit 5C generates a routing table 32 in which the GD 32A is “5B”, the LD 32B is “5B”, and the evaluation value 32C is “E”. The communication unit 5F that has received the Hello frame generates the link table 31 in which the LS 31A is “5B” and the return path weight value 31B is “15”. Further, the communication unit 5F generates a routing table 32 in which the GD 32A is “5B”, the LD 32B is “5B”, and the evaluation value 32C is “E”. The evaluation value “E” indicates not evaluated.

  The GW 7A that has received the Hello frame generates a link table 31 in which the LS 31A is “5B” and the return path weight value 31B is “10”. Further, the GW 7A generates a routing table 32 in which the GD 32A is “5B”, the LD 32B is “5B”, and the evaluation value 32C is “E”.

  FIG. 11 is an explanatory diagram illustrating an example of updating the link table 31 and the routing table 32. The communication unit 5C shown in FIG. 11 wirelessly transmits a Hello frame within its own wireless area. At this time, since the communication unit 5C manages the route information of the adjacent communication unit 5B, the communication unit 5C transmits a Hello frame including the route information related to the communication unit 5B. As a result, adjacent units in the radio area, for example, the communication units 5B, 5D, and 5E receive the Hello frame from the communication unit 5C.

  The communication unit 5B that has received the Hello frame generates the link table 31 in which the LS 31A is “5C”, the return path, the forward path, and the bidirectional weight values 31B to 31D are “20”. The communication unit 5 calculates the forward weight value 31C based on the RSSI of the forward path, and calculates the bidirectional weight value 31D based on the previously obtained return weight value 31B and the forward weight value 31C. Further, the communication unit 5B generates the routing table 32 in which the GD 32A is “5C”, the LD 32B is “5C”, and the evaluation value 32C is “25”.

  The communication unit 5D that has received the Hello frame generates a link table 31 in which the LS 31A is “5C” and the return path weight value 31B is “30”. Further, in the communication unit 5D, GD32A is “5C”, LD32B is “5C”, evaluation value 32C is “E”, GD32A is “5B”, LD32B is “5C”, and evaluation value 32C is “E”. A routing table 32 is generated. Further, the communication unit 5E that has received the Hello frame generates a link table 31 in which the LS 31A is “5C” and the return path weight value 31B is “20”. The communication unit 5E has a routing table in which GD32A is "5C", LD32B is "5C" and evaluation value 32C is "E", GD32A is "5B", LD32B is "5C" and evaluation value 32C is "E". 32 is generated.

  That is, the GW 7, the communication unit 5, and the relay unit 6 receive the Hello frame from the adjacent unit, and update the contents of the routing table 32 and the link table 31 based on the received Hello frame. The GW 7, the communication unit 5, and the relay unit 6 route communication paths in the multihop system 3 based on the contents of the routing table 32 and the link table 31.

  FIG. 12 is an explanatory diagram showing an example of use of the routing table 32. For convenience of explanation, the communication unit 5C manages up to three first to third adjacent destinations (LD) 32B and evaluation values 32C for each final destination (GD) 32A. In the example illustrated in FIG. 12, for example, when the final destination (GD) 32A is “5B”, the adjacent destination (LD) 32B is “5B”, “5D”, and “5E”. The evaluation value 32C is “5”, “50”, and “60”. When the communication unit 5C transmits data to “5B” of the final destination (GD) 32A, the routing table 32 is referred to, and the route of the adjacent destination “5B” having the best evaluation value 32C, that is, the small “5” is selected. select. As a result, the communication unit 5C transmits data to the communication unit 5 of “5B”.

  FIG. 13 is an explanatory diagram illustrating an example of updating the routing table 32. For convenience of explanation, the communication unit 5B relays data from the GW 7A to the communication unit 5C. Further, the communication unit 5C transmits “ACK” as a response to the data to the communication unit 5B. The communication unit 5B manages the routing table 32 of “5C”, “5F”, and “7A” of the adjacent destination 32B with respect to the communication unit 5G of the final destination (GD) 32A.

  The communication unit 5B receives data addressed to the communication unit 5G from the GW 7A, refers to the evaluation value 32C of the routing table 32, determines the communication unit 5C of the adjacent destination 32B as a relay destination, and the communication unit 5C which is the adjacent destination 32B. Send data to. As a result, the communication unit 5B updates and registers the latest adjacent destination 33H of the transfer frame as “5C” in the frame transfer table 33.

  Further, when the communication unit 5B receives a response (ACK) to the transfer frame from the communication unit 5C, the communication unit 5B increases the evaluation value 32C corresponding to “5C” of the adjacent destination 32B to “10” and changes the contents of the routing table 32. Update. That is, the routing table 32 dynamically updates the evaluation value 32C in accordance with not only the RSSI when the Hello frame is received but also the data transfer performance.

  Next, the operation of the communication system 1 of the present embodiment will be described. FIG. 14 is a flowchart illustrating an example of a processing operation of the processor 55 on the communication unit 5 side related to the GW switching selection process. The GW switching selection process shown in FIG. 14 determines whether or not the own unit corresponds to the movement target based on the number of connected GWs 7. If the corresponding unit corresponds to the movement target, the own unit is switched and connected to the accommodation candidate GW 7B. It is processing.

  In FIG. 14, the collection unit 68A in the control unit 68 of the processor 55 determines whether or not the number of connected units (GW1, GW2) has been periodically received from the peripheral GW 7, for example, the accommodating GW 7A and the accommodating candidate GW 7B (step S11). The collection unit 68A selects the accommodation candidate GW 7B based on the GW arrival hop count 96A when periodically receiving a Hello frame to which the number of connections 96B and the GW arrival hop count 96A are added. When the calculation unit 68B in the control unit 68 receives the number of connected GW 7A and the candidate accommodation GW 7B (Yes in Step S11), the calculation unit 68B subtracts the number of connection candidate GW 7B from the number of connections of the accommodating GW 7A to obtain the difference (GW1- GW2) is calculated. Furthermore, the calculation unit 68B determines whether or not the difference (GW1−GW2) exceeds the difference threshold L (step S12). When the difference exceeds the difference threshold L (Yes at Step S12), the calculation unit 68B determines whether or not the communication condition of the accommodation candidate GW 7B is satisfied (Step S13). The communication condition is a condition indicating whether or not the number of allowable hops, RSSI, and the like for accommodating and connecting the communication unit 5 in the accommodation candidate GW 7B are satisfied.

  When the communication condition of the accommodation candidate GW 7B is satisfied (Yes at Step S13), the calculation unit 68B calculates the number of movement target GW 7A (Step S14). The calculating unit 68A calculates the movement target number T by INT (GW1-GW2) * k.

  Further, the determination unit 68C calculates a random value P based on the number of connected GWs 7A connected (GW1) and a random number (step S15). The determination unit 68C calculates the random value P by INT (GW1) * Rand () + 1). Then, the determination unit 68C determines whether or not the own unit corresponds to the movement target based on the number T of movement targets T in step S14 and the random value P in step S15 (step S16). The determination unit 68C determines that the own unit corresponds to the movement target when the random value P ≦ the movement target T. Further, when the random number P ≦ the movement target T is not satisfied, the determination unit 68C determines that the own unit does not correspond to the movement target.

  The switching control unit 68D in the control unit 68 makes a connection request to the accommodation candidate GW 7B when the own unit corresponds to the movement target (Yes at Step S16) (Step S17). The switching control unit 68D determines whether a response to the connection request has been received from the accommodation candidate GW 7B (step S18). When the switching control unit 68D receives a response to the connection request (Yes at Step S18), the switching control unit 68D issues a disconnection request to the accommodating GW 7A (Step S19). The switching control unit 68D determines whether a response to the disconnection request has been received from the main GW 7A (step S20).

  When the switching control unit 68D receives a response to the disconnection request (Yes at Step S20), the address of the accommodating candidate GW7B before switching is registered in the main GW address area, and the address of the accommodating GW 7A before switching is registered in the sub GW address area. (Step S21). Then, the switching control unit 68D ends the processing operation shown in FIG. As a result, the communication unit 5 is switched and connected from the accommodating GW 7A to the accommodating candidate GW 7B.

  Furthermore, when the switching control unit 68D has not received a response to the connection request from the accommodation candidate GW 7B (No at Step S18), the switching control unit 68D determines whether or not a certain time has elapsed from the connection request to the accommodation candidate GW 7B (Step S22). . When a predetermined time has elapsed from the connection request (Yes at Step S22), the switching control unit 68D proceeds to Step S17 to make a connection request to the accommodation candidate GW 7B. For example, when the connection request for the accommodation candidate GW 7B is executed a predetermined number of times and a response to the connection request cannot be received, the process may be interrupted and the process may proceed to step S11. In addition, when a predetermined time has not elapsed since the connection request to the accommodation candidate GW 7B (No at Step S22), the switching control unit 68D proceeds to Step S18 in order to determine whether or not a response to the connection request has been received. .

  Further, when the switching control unit 68D has not received a response to the disconnection request from the accommodating GW 7A (No at Step S20), the switching control unit 68D determines whether a certain time has elapsed from the disconnection request to the accommodating GW 7A (Step S23). . When a predetermined time has elapsed from the disconnection request (Yes at Step S23), the switching control unit 68D proceeds to Step S19 in order to make a disconnection request to the accommodating GW 7A. In addition, when a predetermined time has not elapsed since the disconnection request to the GW 7A being accommodated (No at Step S23), the switching control unit 68D proceeds to Step S20 in order to determine whether a response to the disconnection request has been received. .

  If the collection unit 68A has not received the number of connected GWs 7A and the candidate GW 7B being accommodated (No at Step S11), the collection unit 68A proceeds to Step S11 to continuously monitor the reception of the number of connections. If the difference in the number of connected units (GW1−GW2) does not exceed the difference threshold L (No at Step S12), the calculating unit 68B proceeds to Step S11 to continuously monitor reception of the number of connected units. In addition, when the communication condition of the accommodation candidate GW 7B is not satisfied (No at Step S13), the calculation unit 68B maintains the route of the existing accommodating GW 7 (Step S24), and continuously monitors the reception of the number of connected units. The process proceeds to S11. If there is another accommodation candidate GW 7B while maintaining the existing accommodation GW 7A route, the calculation unit 68B proceeds to step S12 using the number of connected other accommodation candidates GW 7B. Also good. If the unit does not correspond to the movement target (No at Step S16), the determination unit 68C proceeds to Step S11 in order to continuously monitor reception of the next connected number.

  In the GW switching selection process illustrated in FIG. 14, when the difference (GW1−GW2) exceeds the difference threshold L in the communication unit 5 on the accommodated GW 7A side, the difference is multiplied by a coefficient k and the number T of the accommodated GW 7 to be moved T Is calculated. Further, the communication unit 5 calculates the random value P based on the number of connected GWs 7A (GW1) and the random number. And the communication unit 5 determines with having corresponded to movement object, when the random value P is below the movement object number T. When the communication unit 5 corresponds to the movement target, the communication unit 5 switches and connects the accommodating GW 7A to the accommodating candidate GW 7B. Then, by repeating the GW switching selection process, the difference between the number of connected GWs 7A being accommodated and the number of accommodated GWs 7B is gradually converged to a difference threshold L or less. As a result, the number of connected GWs 7A being accommodated and the candidate GWs 7B can be equalized.

  In step S11, the accommodation candidate GW 7B is determined based on the GW arrival hop count 96A in each Hello frame received by the collection unit 68A. However, all the Hello frames received from the GWs 7 other than the accommodating GW 7A may be regarded as being from the accommodating candidate GW 7B without specifying the accommodating candidate GW 7A. In this case, the control unit 68 can determine the true accommodation candidate GW7B based on the determination result of whether or not the communication condition is satisfied in the process of step S13.

  FIG. 15 is an explanatory diagram illustrating an example of convergence of the number of connected GW 7A being accommodated and the candidate GW 7B being accommodated. The number of connected GWs 7A shown in FIG. 15 (GW1) is 600, the number of connected candidate GW7B (GW2) is 100, the difference threshold L is 200, and the coefficient k is 0.1. Then, the communication unit 5 connected to the accommodated GW 7A executes the GW switching selection process once, so that, for example, the number of connected GWs 7A (GW1) is 550 and the number of accommodation candidates GW 7B is connected (GW2). Move to 150 units. Then, the GW switching selection process is repeated a plurality of times, and the communication unit 5 connected to the accommodating GW 7 is gradually switched and connected to the accommodating candidate GW 7B. As a result, the difference between the number of connected GWs 7A being accommodated and the number of connected candidate GWs 7B gradually converges to a difference threshold L or less.

  In the present embodiment, it is determined whether or not the communication unit 5 under the GW 7A being accommodated autonomously corresponds to the movement target. When it is determined that the communication unit 5 corresponds to the movement target, the communication unit 5 switches and connects the accommodation candidate GW 7A to the accommodation candidate GW 7B, and converges the difference between the number of connected GWs 7A and the number of accommodation candidates GW 7B within the difference threshold L. . As a result, the difference in the number of connected GWs 7A and the candidate GW 7B is gradually converged to the difference threshold L or less to equalize the number of connected units, thereby preventing the occurrence of wireless congestion due to the concentration of connected GWs 7A.

  Further, in the present embodiment, the number of connected GWs 7A and the candidate accommodations GW7B is equalized, and the number of path information of the communication units 5 managed in the table by the accommodating GWs 7A and the candidate accommodations GW7B can be equalized. As a result, the accommodated GW 7A can register the new communication unit 5 because there is a space in the table even when the new communication unit 5 is arranged in the vicinity.

  Further, in this embodiment, even if the wireless route is biased due to obstacles in the wireless route, each communication unit 5 of the accommodating GW 7A corresponding to the movement target autonomously switches and connects to the accommodating candidate GW 7B. The bias of the route can be reduced.

  Further, in this embodiment, the difference in the number of connected GWs 7A and GW7B being accommodated is not equalized at a stretch, but only the communication units 5 that are within the number T of movement targets and that are subject to movement using random numbers. Was switched and connected to the accommodation candidate GW7B to gradually equalize. As a result, it is possible to reliably prevent instability of the communication system 1 due to fluctuations in the number of connected connections even when the wireless path is interrupted by an obstacle or the like and immediately recovers.

  Further, in this embodiment, when calculating the movement target number T, the coefficient k that is multiplied by the difference between the number of connected GW 7A and the accommodation candidate GW 7B is adjusted, so the movement that moves from the accommodation GW 7A to the accommodation candidate GW 7B It is possible to easily adjust the target moving target number T. In addition, by changing the coefficient k and adjusting the number T of movement targets, it is possible to adjust the amount of change in the number of connected units of the accommodating GW 7A and the accommodating candidate GW 7B. As a result, a situation in which the communication system 1 becomes unstable due to a sudden change in the number of connected devices can be avoided.

  Moreover, in the said Example, only if the connection number of accommodation candidate GW7B is deducted from the connection number of accommodation GW7A, and the difference (GW1-GW2) exceeds the difference threshold L, it is a movement object from the communication unit 5 of accommodation GW7A. It was judged whether it corresponded to. As a result, each communication unit 5 of the accommodating GW 7A can suppress unnecessary processing for switching the communication unit 5 to the accommodating candidate GW 7B when the difference is small.

  Moreover, in the said Example, each GW7 transmits a Hello frame with a period of 10 minutes, a slight delay arises until a Hello frame arrives at the terminal communication unit 5 under GW7, and each communication unit 5 side There is a time difference in obtaining the Hello frame. However, for example, the communication unit 5 used in the present system is often fixedly disposed in a home power meter, and the number of connected units is less likely to fluctuate during the difference in acquisition time of each Hello frame. Moreover, as described above, the communication unit 5 corresponding to the movement target in the accommodating GW 7A is gradually switched and connected to the accommodating candidate GW 7B. As a result, even if the number of connected devices varies due to the difference in acquisition time of each Hello frame, a situation in which the communication system 1 becomes unstable due to the variation of the number of connected devices can be avoided.

  In the above embodiment, the number T of movement targets is calculated by (GW1-GW2) * k. In this case, the determination algorithm 1 is IF ((GW1-GW2)> L) {T = INT ((GW1-GW2) * k) P = Int (GW1 * Rnd () + 1) IF (P <= T) { Move target} else {not move target}}. Therefore, the simulation was performed by the GW switching selection process using the determination algorithm 1. FIG. 16A is an explanatory diagram illustrating an example of the convergence transition of the number of connected units simulated by the determination algorithm 1. In FIG. 16A, the number of connected GWs 7A being accommodated is 550, the number of accommodation candidates GW 7B is 150, the difference threshold L is 100, and the coefficient k is 0.1. For example, in the fifth GW switching selection process, the number of connected GWs 7A accommodated is 395, and the number of accommodated candidate GWs 7B converges to 305. However, it is a simulation result when the number of objects to be moved with random numbers becomes T in total.

  Alternatively, the movement target number T may be calculated by multiplying 1/2 of the difference (GW1−GW2) by a coefficient k. In this case, the determination algorithm 2 is IF ((GW1-GW2)> L) {T = INT ((GW1-GW2) / 2 * k) P = Int (GW1 * Rnd () + 1) IF (P <= T ) {Movement object} else {non-movement object}}. Therefore, the simulation was performed by the GW switching selection process using the determination algorithm 2. FIG. 16B is an explanatory diagram illustrating an example of the convergence transition of the number of connected units simulated by the determination algorithm 2. FIG. 16B assumes that the number of connected GWs 7A being accommodated is 475, the number of accommodated candidate GWs 7B is 225, the difference threshold L is 100, and the coefficient k is 0.5. For example, in the third GW switching selection process, the result is that the number of connected GWs 7A accommodated is 381 and the number of accommodated candidate GWs 7B converges to 319.

  Alternatively, the movement target number T may be calculated by multiplying 1/2 of the difference (GW1−GW2) by the ratio of the number of connected sub-GWs 7B to the number of connected main GW1 and the coefficient k. In this case, the determination algorithm 3 is IF ((GW1-GW2)> L) {T = INT ((GW1-GW2) / 2 * (GW2 / GW1) * k) P = Int (GW1 * Rnd () + 1) IF (P <= T) {movement object} else {non-movement object}}. Therefore, the simulation was performed by the GW switching selection process using the determination algorithm 3. FIG. 16C is an explanatory diagram illustrating an example of the convergence transition of the number of connected units simulated by the determination algorithm 3. FIG. 16C assumes that the number of connected GWs 7A being accommodated is 495, the number of accommodated candidate GWs 7B is 205, the difference threshold L is 100, and the coefficient k is 0.5. For example, in the second GW switching selection process, the number of connected GWs 7A accommodated is 396, and the number of accommodated accommodation candidate GWs 7B converges to 304.

  Alternatively, the connected number of sub-GWs 7B may be received, and the moving target number T may be calculated by multiplying the ratio of 1/2 of the difference (GW−GW2) and the target sub-GW by a coefficient k. In this case, the determination algorithm 4 is IF ((GW1-GW2)> L) {IF ((GW1-GW2) / 2 <GW2) {T = INT ((GW1-GW2) / 2 / GW2 * k)} else {T = INT (GW2 * k)} P = Int (GW1 * Rnd () + 1) IF (P <= T) {movement target} else {non-movement target}}. Therefore, the simulation was performed by the GW switching selection process using the determination algorithm 4. FIG. 16D is an explanatory diagram illustrating an example of the convergence transition of the number of connected units simulated by the determination algorithm 4. In FIG. 16D, the number of connected GWs 7A is 400, the number of connections of the candidate GW 7B is 300, the difference threshold L is 100, and the coefficient k is 0.8. Then, for example, in the second GW switching selection process, the number of connected GWs 7A is converged to 361, and the number of accommodated candidate GWs 7B converges to 339.

  Further, in the above-described embodiment, for convenience of explanation, the description has been given by taking, as an example, one accommodating GW 7A as the accommodated communication accommodating apparatus and one accommodating candidate GW 7B as the candidate accommodating communication accommodating apparatus. However, the accommodation candidate GW 7B is not limited to one, and may be a plurality. In addition, the accommodating GW 7A may be the main GW, and the accommodating candidate GW 7B may be the sub GW 7 that is dependent on the main GW 7.

  Moreover, in the said Example, although the communication unit 5 was illustrated as a movement object, it is not limited to the communication unit 5, The relay unit 6 may be sufficient.

  Moreover, in the said Example, it was determined whether all the communication units 5 connected to accommodated GW7A corresponded to the movement object with the winning probability of the same coefficient k. However, the communication unit 5 connected to the accommodated GW 7A has a coefficient k to increase the winning probability of the communication unit 5 according to the gradual increase in the number of hops to the accommodated GW 7A based on the GW arrival hop count 96A in the Hello frame. May be gradually increased. As a result, compared with the communication unit 5 with a small number of hops among the communication units 5 within the accommodated GW 7A, the communication unit 5 that is far from the accommodated GW 7A and has a large number of hops is preferentially switched. The influence of switching can be reduced and the communication system 1 can be stabilized.

  Moreover, in the said Example, you may make it increase the coefficient k gradually according to the increase of the number of the communication units 5 to relay among the communication units 5 connected to GW7A in accommodation. As a result, compared with the communication unit 5 with a large number of relays among the communication units 5 in the accommodated GW 7A, switching from the communication unit 5 with a small number of relays has a lower switching effect. The communication system 1 can be stabilized.

  Moreover, in the said Example, each GW7 manages the address of the communication unit 5 currently accommodated as a main GW, and the communication unit 5 which can be accommodated as a sub GW, and each GW7 is unicast about the number of its connection. You may notify to each communication unit 5 which has grasped | ascertained the address. As a result, each communication unit 5 can collect the number of connected main GWs and the number of connected sub-GWs.

  In the above embodiment, the time at which the Hello frame is transmitted on the GW 7 side may be added to the Hello frame in addition to the GW arrival hop count 96A and the connection count 96B. In this case, the communication unit 5 deducts the number of connections of the accommodation candidate GW 7B from the number of connections of the accommodation GW 7A only when the difference in time information in the Hello frame obtained from the accommodation GW 7A and the accommodation candidate GW 7B is acceptable. The difference (GW1-GW2) may be calculated.

  Moreover, in the said Example, you may add the evaluation value which considered the successful track record of RSSI and data transmission instead of GW arrival hop count 96A in a Hello frame. In this case, the collection unit 68A in each communication unit 5 may determine the accommodation candidate GW 7B based on the received evaluation value in the Hello frame.

  In the above embodiment, the number of connections 96B and the number of GW arrival hops 96A are added to the Hello frame, but the number of connections 96B and the number of GW arrival hops 96A are added to the delivery frames other than the Hello frame. good.

  Further, in the above embodiment, the amount of change between the previous difference related to the connected number GW1 collected by the collecting unit 68A and the current difference related to the number of connected items collected immediately before by the collecting unit 68A is a constant change amount. If it is less than the threshold, the coefficient k is increased. For example, in addition to the communication unit 5 of this embodiment, when other communication units that cannot execute the GW switching selection process are mixed in the communication system 1, the number of other communication units is included in the number of connected units. It is also conceivable that the amount of change between this difference and the current difference becomes extremely small. Therefore, in this case, if the amount of change between the previous difference and the current difference is less than the change amount threshold, the coefficient k is increased to increase the number T of movement targets, thereby increasing the winning probability of the movement target and the change amount. You may make it increase. When the change amount exceeds the change amount threshold value, the coefficient k is returned to the original value.

  In the above-described embodiment, the communication system 1 adopting autonomous multi-hop wireless communication is exemplified and described as ad hoc communication. However, the communication system 1 is not limited to wireless communication, and is not limited to infrared communication or wired communication. Is also applicable.

  In addition, each component of each part illustrated does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution / integration of each part is not limited to the one shown in the figure, and all or a part thereof may be functionally or physically distributed / integrated in arbitrary units according to various loads and usage conditions. Can be configured.

  Furthermore, various processing functions performed in each device are performed on a CPU (Central Processing Unit) (or a microcomputer such as an MPU (Micro Processing Unit), MCU (Micro Controller Unit), etc.) in whole or in part. You may make it perform. Various processing functions may be executed entirely or arbitrarily on a program that is analyzed and executed by a CPU (or a microcomputer such as an MPU or MCU) or hardware based on wired logic. Needless to say.

  By the way, the various processes described in the present embodiment can be realized by executing a program prepared in advance on a communication device. Therefore, in the following, an example of a communication device that executes a program having the same function as the above embodiment will be described. FIG. 17 is an explanatory diagram illustrating an example of a communication device that executes a switching control program.

  A communication device 100 that executes the switching control program illustrated in FIG. 17 includes a communication interface 111, a RAM (Random Access Memory) 112, a ROM (Read Only Memory) 113, and a processor 114. The communication interface 111 performs wireless communication using an autonomous multi-hop method. The processor 114 controls the entire communication device 100.

  The ROM 113 stores in advance a switching control program that exhibits the same function as in the above embodiment. Note that the switching control program may be recorded on a recording medium readable by a drive (not shown) instead of the ROM 113. The recording medium may be, for example, a portable recording medium such as a CD-ROM, a DVD disk, or a USB memory, or a semiconductor memory such as a flash memory. As shown in FIG. 17, the switching control programs are a collection program 113A, a calculation program 113B, a determination program 113C, and a switching control program 113D. Note that the programs 113A to 113D may be integrated or distributed as appropriate.

  Then, the processor 114 reads the programs 113A to 113D from the ROM 113, and executes each read program. As shown in FIG. 17, the processor 114 functions as the collection process 114A, the calculation process 114B, the determination process 114C, and the switching control process 114D.

  The processor 114 collects the number of connected communication devices connected to the accommodated communication accommodation device from the accommodated communication accommodation device, and communicates the accommodation candidate from the accommodation candidate communication accommodation device capable of communication connection. Collects the number of connected communication devices to which the device communicates. Furthermore, the processor 114 changes from the accommodated communication accommodation device to the accommodation candidate communication accommodation device based on the difference between the collected number of connections on the accommodated communication accommodation device side and the number of connections on the candidate communication accommodation device side. The number of movement target communication devices to be moved is calculated. Furthermore, the processor 114 determines whether or not it corresponds to the movement target based on the number of movement targets, the number of connections on the side of the communication accommodation apparatus being accommodated, and the random number. Furthermore, the processor 114 requests the accommodation candidate communication accommodation apparatus to perform a switching connection from the accommodated communication accommodation apparatus to the accommodation candidate communication accommodation apparatus when it corresponds to the movement target. As a result, the number of connected communication accommodation devices can be adjusted by an autonomous operation on the side of the communication device connected to the communication accommodation device.

  As described above, the following supplementary notes are further disclosed regarding the embodiment including the present example.

(Supplementary Note 1) A communication unit that is communicably connected to a communication accommodation device that is being accommodated, and that is communicably connected to a communication accommodation device that is an accommodation candidate,
A communication device that collects the number of connected communication devices to which the accommodated communication accommodation device communicates from the accommodated communication accommodation device, and communicates and connects the accommodation candidate communication accommodation device to the accommodation candidate communication accommodation device. A collection unit that collects the number of connected
Based on the difference between the collected number of connections on the side of the accommodated communication accommodation device and the number of connections on the side of the accommodation candidate communication accommodation device, move from the accommodated communication accommodation device to the candidate communication accommodation device A calculating unit that calculates the number of moving target communication devices to be moved;
A determination unit that determines whether or not the object corresponds to the movement target, based on the number of movement targets, the number of connections on the side of the communication accommodation device being accommodated, and a random number;
And a control unit that requests switching connection from the accommodated communication accommodation device to the accommodation candidate communication accommodation device to the accommodation candidate communication accommodation device when it corresponds to the movement target. apparatus.

(Supplementary Note 2) The calculation unit
The communication apparatus according to appendix 1, wherein the difference is multiplied by a coefficient of 1 or less to calculate the number of objects to be moved.

(Supplementary Note 3) The calculation unit
The communication apparatus according to appendix 1 or 2, wherein when the difference exceeds a difference threshold, the number of movement targets is calculated based on the difference.

(Supplementary Note 4) The calculation unit
The communication apparatus according to appendix 2, wherein the coefficient is gradually increased according to a gradual increase in the number of hops until connection to the accommodated communication accommodating apparatus.

(Supplementary Note 5) The calculation unit
The communication apparatus according to appendix 2, wherein the coefficient is gradually decreased in accordance with a gradual increase in the number of communication apparatuses to be relayed.

(Appendix 6) The calculation unit
Increase the coefficient when the difference between the previous difference related to the number of connections collected last time by the collection unit and the current difference related to the number of connections collected immediately after the previous time by the collection unit is less than the change amount threshold. The communication apparatus according to appendix 2, wherein the communication apparatus is characterized in that

(Supplementary note 7) A communication system having a plurality of communication devices and a plurality of communication accommodation devices for accommodating the plurality of communication devices,
Among the plurality of communication accommodation devices, a communication accommodation device being accommodated to which the communication device communicates and a communication accommodation device that is a candidate for accommodation to which the communication device can be connected,
A notification unit for notifying each communication device of the number of connected communication devices;
Each of the plurality of communication devices is
Collecting the number of connections on the side of the accommodated communication accommodation device notified from the accommodated communication accommodation device, and calculating the number of connections on the side of the accommodation candidate communicated from the accommodation candidate communication accommodation device A collection unit to collect,
Based on the difference between the collected number of connections on the side of the accommodated communication accommodation device and the number of connections on the side of the accommodation candidate communication accommodation device, move from the accommodated communication accommodation device to the candidate communication accommodation device A calculating unit that calculates the number of moving target communication devices to be moved;
A determination unit that determines whether or not the object corresponds to the movement target, based on the number of movement targets, the number of connections on the side of the communication accommodation device being accommodated, and a random number;
And a control unit that requests switching connection from the accommodated communication accommodation device to the accommodation candidate communication accommodation device to the accommodation candidate communication accommodation device when it corresponds to the movement target. system.

(Supplementary note 8) A switching control method for a communication system having a plurality of communication devices and a plurality of communication accommodating devices accommodating the plurality of communication devices,
Each of the plurality of communication devices is
The number of connected communication devices to which the accommodated communication accommodation device communicates from the accommodated communication accommodation device, and the accommodation candidate communication accommodation device from the communication candidate of the accommodation candidate capable of communication connection. Collect the number of connected communication devices,
Based on the difference between the collected number of connections on the side of the accommodated communication accommodation device and the number of connections on the side of the accommodation candidate communication accommodation device, the communication accommodating device being accommodated moves to the communication accommodation device of the accommodation candidate. Calculate the number of moving target communication devices,
Based on the number of moving objects, the number of connected devices on the side of the communication accommodation device being accommodated, and a random number, it is determined whether it corresponds to the movement object,
The switching is characterized in that, when the object corresponds to the movement target, each process for requesting the connection candidate communication accommodation device to switch to the accommodation candidate communication accommodation device from the accommodated communication accommodation device is executed. Control method.

(Supplementary note 9) A switching control program executed by a communication device having a communication interface and a processor for communication,
In the processor,
The number of connected communication devices to which the accommodated communication accommodation device communicates from the accommodated communication accommodation device, and the accommodation candidate communication accommodation device from the communication candidate of the accommodation candidate capable of communication connection. Collect the number of connected communication devices,
Based on the difference between the collected number of connections on the side of the accommodated communication accommodation device and the number of connections on the side of the accommodation candidate communication accommodation device, the communication accommodating device being accommodated moves to the communication accommodation device of the accommodation candidate. Calculate the number of moving target communication devices,
Based on the number of movement targets, the number of connections on the side of the communication accommodation device being accommodated, and a random number, it is determined whether it corresponds to the movement target,
Switching that is characterized by causing each of the accommodation candidate communication accommodation devices to execute a switching connection from the accommodated communication accommodation device to the accommodation candidate communication accommodation device when corresponding to the movement target. Control program.

1 communication system 5 communication unit 7 GW
GW during 7A accommodation
7B Containment candidate GW
22 wireless communication unit 30 control unit 61 wireless communication unit 68A collection unit 68B calculation unit 68C determination unit 68D switching control unit 100 communication device 111 communication interface 112 RAM
113 ROM
114 processor 114A collection process 114B calculation process 114C determination process 114D switching control process

Claims (8)

A communication unit capable of communication connection with a communication accommodating device being accommodated, and a communication unit capable of communication connection with a candidate communication accommodating device,
A communication device that collects the number of connected communication devices to which the accommodated communication accommodation device communicates from the accommodated communication accommodation device, and communicates and connects the accommodation candidate communication accommodation device to the accommodation candidate communication accommodation device. A collection unit that collects the number of connected
Based on the difference between the collected number of connections on the side of the accommodated communication accommodation device and the number of connections on the side of the accommodation candidate communication accommodation device, move from the accommodated communication accommodation device to the candidate communication accommodation device A calculating unit that calculates the number of moving target communication devices to be moved;
A determination unit that determines whether or not the object corresponds to the movement target, based on the number of movement targets, the number of connections on the side of the communication accommodation device being accommodated, and a random number;
And a control unit that requests switching connection from the accommodated communication accommodation device to the accommodation candidate communication accommodation device to the accommodation candidate communication accommodation device when it corresponds to the movement target. apparatus. The calculation unit includes:
The communication apparatus according to claim 1, wherein the number of movement targets is calculated by multiplying the difference by a coefficient of 1 or less. The calculation unit includes:
The communication apparatus according to claim 2, wherein the coefficient is gradually increased in accordance with a gradual increase in the number of hops until connection to the accommodated communication accommodating apparatus. The calculation unit includes:
The communication apparatus according to claim 2, wherein the coefficient is gradually decreased in accordance with a gradual increase in the number of communication apparatuses to be relayed. The calculation unit includes:
Increase the coefficient when the difference between the previous difference related to the number of connections collected last time by the collection unit and the current difference related to the number of connections collected immediately after the previous time by the collection unit is less than the change amount threshold. The communication apparatus according to claim 2, wherein A communication system having a plurality of communication devices and a plurality of communication accommodating devices accommodating the plurality of communication devices,
Among the plurality of communication accommodation devices, a communication accommodation device being accommodated to which the communication device communicates and a communication accommodation device that is a candidate for accommodation to which the communication device can be connected,
A notification unit for notifying each communication device of the number of connected communication devices;
Each of the plurality of communication devices is
Collecting the number of connections on the side of the accommodated communication accommodation device notified from the accommodated communication accommodation device, and calculating the number of connections on the side of the accommodation candidate communicated from the accommodation candidate communication accommodation device A collection unit to collect,
Based on the difference between the collected number of connections on the side of the accommodated communication accommodation device and the number of connections on the side of the accommodation candidate communication accommodation device, move from the accommodated communication accommodation device to the candidate communication accommodation device A calculating unit that calculates the number of moving target communication devices to be moved;
A determination unit that determines whether or not the object corresponds to the movement target, based on the number of movement targets, the number of connections on the side of the communication accommodation device being accommodated, and a random number;
And a control unit that requests switching connection from the accommodated communication accommodation device to the accommodation candidate communication accommodation device to the accommodation candidate communication accommodation device when it corresponds to the movement target. system. A switching control method for a communication system having a plurality of communication devices and a plurality of communication accommodating devices accommodating the plurality of communication devices,
Each of the plurality of communication devices is
Collecting the number of connected communication devices to which the accommodated communication accommodation device communicates from the accommodated communication accommodation device, and communicating from the accommodation candidate communication accommodation device capable of communication connection to the accommodation candidate communication accommodation device Collects the number of connected communication devices
Based on the difference between the collected number of connections on the side of the accommodated communication accommodation device and the number of connections on the side of the accommodation candidate communication accommodation device, the communication accommodating device being accommodated moves to the communication accommodation device of the accommodation candidate. Calculate the number of moving target communication devices,
Based on the number of moving objects, the number of connected devices on the side of the communication accommodation device being accommodated, and a random number, it is determined whether it corresponds to the movement object,
The switching is characterized in that, when the object corresponds to the movement target, each process for requesting the connection candidate communication accommodation device to switch to the accommodation candidate communication accommodation device from the accommodated communication accommodation device is executed. Control method. A switching control program executed by a communication device having a communication interface for communication and a processor,
In the processor,
Collecting the number of connected communication devices to which the accommodated communication accommodation device communicates from the accommodated communication accommodation device, and communicating from the accommodation candidate communication accommodation device capable of communication connection to the accommodation candidate communication accommodation device Collects the number of connected communication devices
Based on the difference between the collected number of connections on the side of the accommodated communication accommodation device and the number of connections on the side of the accommodation candidate communication accommodation device, the communication accommodating device being accommodated moves to the communication accommodation device of the accommodation candidate. Calculate the number of moving target communication devices,
Based on the number of movement targets, the number of connections on the side of the communication accommodation device being accommodated, and a random number, it is determined whether it corresponds to the movement target,
Switching that is characterized by causing each of the accommodation candidate communication accommodation devices to execute a switching connection from the accommodated communication accommodation device to the accommodation candidate communication accommodation device when corresponding to the movement target. Control program.

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