JP2013214834A - Communication system, communication device, path switching method, and path switching program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system and the like that can quickly achieve path switching intended by a user.SOLUTION: A communication system 1 comprises a plurality of communication units 5 and relay units 6 that perform connection by autonomous multi-hop type radio communication. A relay unit 6 wirelessly transmits a relay Hello frame including a relay flag and a maximum propagation hop number. A communication unit 5 includes: a routing table 32 storing a relay destination of data to a final destination per final destination; a radio communication unit 61 for transmitting data to a relay destination corresponding to the final destination referring to the routing table; an update unit 68A for updating the routing table such that a relay unit 6 having transmitted a frame becomes a first priority neighboring destination LD1 of the final destination when a relay Hello frame is received from the relay unit 6; and a control unit 68B for controlling radio transmission of the frame on the basis of the maximum propagation hop number within the relay Hello frame.

Description

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

  2. Description of the Related Art In recent years, autonomous multi-hop systems, in which each communication unit autonomously performs routing and wirelessly transmits data using a multi-hop system, are widely known. In an autonomous multi-hop system, each communication unit periodically exchanges route information with an adjacent unit connected in one hop, and updates the route information. 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 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 and relay unit in an autonomous multi-hop 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 route information in accordance with the radio wave quality of the Hello frame and the successful 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. Based on the evaluation value in the routing table, the GW, the communication unit, and the relay unit transmit data to the destination unit through a route having a good evaluation value.

  The GW, the communication unit, and the relay unit update the evaluation value in the routing table in accordance with 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 2007-235945 A JP 2009-81854 A JP 2008-131574 A JP 2009-267532 A JP 2011-9967 A JP 2011-9969 A

  In a conventional communication system, each unit relays data for each final destination, that is, manages a relay destination of adjacent units and evaluation values in a routing table, selects the final destination relay destination based on the evaluation value, and transmits data. To do. However, the evaluation value used for selecting the relay destination depends on the results such as the number of successful data transmissions. For example, even if a new communication unit or relay unit is installed in the system in order to switch the route intended by the user, the newly arranged unit has no communication record, so that the intended route switching cannot be realized. FIG. 23 is an explanatory diagram showing an example of a conventional problem. When the communication unit 201A transmits data from the transmission source GS to the final destination GD, the evaluation value for each adjacent destination corresponding to the final destination GD in the routing table is referred to, the evaluation value of the communication unit 201B is high, and the relay destination As a result, the communication unit 201B is selected.

  At this time, it is assumed that the user places a new communication unit 201C in the communication system in order to switch the relay destination of the communication unit 201A. However, the new communication unit 201C has no communication record. Therefore, in order for the communication unit 201A to switch a new communication unit as a relay destination, it is necessary to accumulate communication results in order to increase the evaluation value, and a great deal of time is required. That is, the actual situation is that the user-intended route switching cannot be realized quickly.

  An object of one aspect is to provide a communication system or the like that can quickly realize route switching intended by a user.

  An aspect of the disclosure is a communication system having a plurality of communication devices connected by autonomous multi-hop communication. Among the plurality of communication devices, the first communication device includes a communication unit that transmits a frame to which the relay flag and the number of propagation hops are added. Among the plurality of communication devices, the second communication device is configured to store, for each destination, a storage unit that stores a relay destination of data to the destination and a relay destination corresponding to the destination with reference to the storage unit. And a communication unit for transmitting. Furthermore, when the second communication device receives the frame from the first communication device, the first communication device that has transmitted the frame is set as the highest priority relay destination of the destination. An update unit for updating the storage unit is provided. The second communication device includes a control unit that controls transmission of the frame based on the number of propagation hops in the frame when the frame is received from the first communication device.

  In the disclosed aspect, it is possible to quickly realize route switching intended by the user.

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 a block diagram illustrating an example of a hardware configuration of the communication unit. FIG. 8 is a block diagram illustrating an example of a functional configuration of the communication unit. FIG. 9 is a block diagram illustrating an example of a hardware configuration of the relay unit. FIG. 10 is a block diagram illustrating an example of a functional configuration of the relay unit. FIG. 11 is an explanatory diagram illustrating an example of a relay Hello frame. FIG. 12 is an explanatory diagram illustrating an example of updating the link table and the routing table. FIG. 13 is an explanatory diagram illustrating an example of updating the link table and the routing table. FIG. 14 is an explanatory diagram showing an example of use of the routing table. FIG. 15 is an explanatory diagram of an example of updating the routing table. FIG. 16A is an explanatory diagram illustrating an example of a route before a relay unit is arranged in the communication system. FIG. 16B is an explanatory diagram illustrating an example of a route when a relay unit is arranged in the communication system. FIG. 17A is an explanatory diagram illustrating an example of the routing table of the communication unit before the relay unit is arranged. FIG. 17B is an explanatory diagram illustrating an example of the routing table of the communication unit after the relay unit is arranged. FIG. 18 is a flowchart illustrating an example of the processing operation of the processor on the relay unit side involved in the route switching request processing. FIG. 19 is a flowchart illustrating an example of the processing operation of the processor on the communication unit side involved in the path switching process. FIG. 20 is a flowchart illustrating an example of the processing operation of the processor on the communication unit side involved in the relay restriction process. FIG. 21 is a flowchart illustrating an example of the processing operation of the processor on the relay unit side involved in the Hello request reception process. FIG. 22 is an explanatory diagram illustrating an example of a communication device that executes a route switching program. FIG. 23 is an explanatory diagram showing an example of a conventional problem.

  Hereinafter, embodiments of a communication system, a communication apparatus, a path switching method, and a path switching 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 multihop system 3 is constructed by an autonomous multihop 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 using 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 wireless in an autonomous multi-hop format, 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 home. 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 route control unit 28 controls an autonomous multi-hop communication route. 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.

  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).

  FIG. 7 is a block diagram illustrating an example of a hardware configuration of the communication unit 5. The communication unit 5 shown in FIG. 7 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 path switching program. The processor 55 controls the entire communication unit 5.

  FIG. 8 is a block diagram illustrating an example of a functional configuration of the communication unit 5. The processor 55 shown in FIG. 8 configures functions serving as various processes based on a program stored in the memory 54. 8 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 control unit 68 includes an update unit 68A and a control unit 68B. The update unit 68 </ b> A updates the routing table 32 when it receives a Hello frame including a relay flag (to be described later) (hereinafter simply referred to as a relay Hello frame). Specifically, the updating unit 68A updates the routing table 32 so that the unit 5 (6) that has transmitted the relay Hello frame becomes the first adjacent destination (LD1) 32B of the final destination 32A. Note that the relay flag identifies a relay Hello frame for which the own unit seeks preferential registration as the first adjacent destination (LD1). When the control unit 68B receives a relay Hello frame, the control unit 68B controls relay of the relay Hello frame based on the maximum number of propagation hops described later in the relay Hello frame. The maximum number of propagation hops indicates the maximum number of hops that can be wirelessly transmitted, that is, relayed, the relay Hello frame on the unit side that has received the relay Hello frame.

  FIG. 9 is a block diagram illustrating an example of a hardware configuration of the relay unit 6. The relay unit 6 illustrated in FIG. 9 includes a wireless interface 71, an auxiliary storage device 72, a memory 73, and a processor 74. The wireless interface 71 is an interface for wirelessly connecting to the multihop system 3. The auxiliary storage device 72 is a flash memory that stores various types of information. The memory 73 is a memory that stores information on various programs such as a path switching program. The processor 74 controls the entire relay unit 6.

  FIG. 10 is a block diagram illustrating an example of a functional configuration of the relay unit 6. The processor 74 shown in FIG. 10 configures functions that serve as various processes based on a program stored in the memory 73. For convenience of explanation, it is assumed that the relay unit 6 wirelessly transmits a relay Hello frame. 10 includes a wireless communication unit 81, a frame analysis unit 82, a data generation unit 83, a data acquisition unit 84, a setting information acquisition unit 85, a route control unit 86, a storage unit 87, The control unit 88 functions. The wireless communication unit 81 controls wireless communication with the multihop system 3 through the wireless interface 71.

  The frame analysis unit 82 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 71. The data generation unit 83 generates data. The data acquisition unit 84 acquires data. The setting information acquisition unit 85 acquires setting information. The route control unit 86 controls an autonomous multi-hop communication route. The route controller 86 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 87 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 control unit 88 includes an adding unit 88A and a control unit 88B. The adding unit 88A controls the relay Hello frame by adding the relay flag and the maximum number of propagation hops in the Hello frame. FIG. 11 is an explanatory diagram illustrating an example of a configuration of a relay Hello frame. The relay Hello frame 90 shown in FIG. 11 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. The sequence number 95B is information for identifying a connection. TTL95D indicates the valid period of the packet. Type 95C identifies a data frame, a Hello frame, or a relay Hello frame. Since the relay Hello frame and Hello frame are not transferred to other units, the TTL 95D and the hop number 95E in the ad hoc header 95 are “1”.

  The maximum propagation hop count 96A in the payload 96 indicates the maximum number of hops at which the relay Hello frame can be wirelessly transmitted (relayed) on the unit side that has received the relay Hello frame. The FCS 97 is used for error detection.

  That is, the adding unit 88A adds a relay flag, that is, a type for identifying the relay Hello frame, to the type 95C in the relay Hello frame 90 shown in FIG. Further, the adding unit 88A adds the maximum number of propagation hops within the maximum number of propagation hops 96A in the payload 96. The control unit 88B controls the wireless communication unit 81 so as to wirelessly transmit a data frame, a Hello frame, and a relay Hello frame. Further, the control unit 88B controls the link table 31, the routing table 32, and the like. When the control unit 88B receives a response to the relay Hello frame, the control unit 88B updates the link table 31 in order to update the link state of the adjacent transmission source (LS) 31A of the communication unit 5, the relay unit 6, or the GW 7 that has responded. . The controller 88B determines whether or not the number of adjacent transmission sources (LS) 31A in the link table 31 has reached the upper limit number. When the number of transmission sources (LS) reaches the upper limit, the control unit 88B stops wireless transmission of the relay Hello frame and stops updating the link table 31.

  FIG. 12 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. 13 is an explanatory diagram illustrating an example of updating the link table 31 and the routing table 32. The communication unit 5C illustrated in FIG. 13 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”.

  In addition, 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 31A 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. 14 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. 14, 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. 15 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.

  FIG. 16A is an explanatory diagram illustrating an example of a route before the relay unit 6 is arranged in the communication system 1. The communication system 1 illustrated in FIG. 16A assumes that the GW 7 is a final destination (GD) and the communication units 5A to 5U are performing path construction based on the evaluation values. At this time, the load is concentrated on the communication unit 5T.

  Therefore, it is assumed that the maintenance person of the communication system 1 newly arranges the relay unit 6 in order to distribute the load of the communication unit 5T, for example. FIG. 16B is an explanatory diagram illustrating an example of a route when the relay unit 6 is arranged in the communication system 1. In this case, when the route with the final destination GW 7 is established, the relay unit 6 wirelessly transmits the relay Hello frame. Each communication unit 5 that has received the relay Hello frame updates the routing table 32 so that it becomes the relay unit 6 at the first adjacent destination (LD1) of the final destination (GD).

  Also, the maximum propagation hop count 96A is included in the relay Hello frame. For example, it is assumed that the communication unit 5N receives a relay Hello frame having a maximum propagation hop count 96A of “2” from the relay unit 6. The communication unit 5N updates the first adjacent destination (LD1) of the final destination (GD) to the relay unit 6. The communication unit 5N can propagate the relay Hello frame by 1 hop because the maximum propagation hop count 96A in the relay Hello frame is “2” and the maximum propagation hop count 96A is decremented by −1 to “1”. . Accordingly, the communication unit 5N wirelessly transmits a relay Hello frame having a maximum propagation hop count 96A of “1”. In addition, when the communication unit 5U receives the relay Hello frame from the communication unit 5N, the communication unit 5U updates the first adjacent destination (LD1) of the final destination. At this time, since the maximum propagation hop count 96A in the relay Hello frame is “1” and the maximum propagation hop count 96A is decremented by −1 and becomes “0”, the communication unit 5U further increases the relay Hello frame. Prohibit propagation. Therefore, the relay unit 6 controls the propagation of the relay Hello frame based on the maximum propagation hop count 96A.

  FIG. 17A is an explanatory diagram illustrating an example of the routing table 32 of the communication unit 5M before the relay unit 6 is arranged. Before arranging the relay unit 6, the communication unit 5M refers to the routing table 32 in FIG. 17A and selects the communication unit 5T as the first adjacent destination (LD1) of the final destination GW7. As a result, the communication unit 5M transmits data to the final destination GW 7 via the communication unit 5T as the first adjacent destination (LD1).

  FIG. 17B is an explanatory diagram illustrating an example of the routing table 32 of the communication unit 5M after the relay unit 6 is arranged. When the relay unit 6 is arranged, the communication unit 5M that has received the relay Hello frame gives priority to the first adjacent destination (LD1) of the final destination GW 7 in the routing table 32 as shown in FIG. 17B. Set to. As a result, the communication unit 5M transmits data to the final destination GW 7 via the relay unit 6 as the first adjacent destination (LD1). Therefore, for example, the load of the communication unit 5T can be distributed.

  Next, the operation of the communication system 1 of the present embodiment will be described. FIG. 18 is a flowchart showing an example of the processing operation of the processor 74 on the relay unit 6 side involved in the route switching request processing. The route switching request process shown in FIG. 18 is performed such that, for example, a newly arranged relay unit 6 makes itself the first adjacent destination (LD1) of the final destination with respect to the peripheral communication unit 5 and the like. This is a process for requesting switching.

  In FIG. 18, the adding unit 88A of the processor 74 of the relay unit 6 generates a relay Hello frame (step S11). The adding unit 88A changes the type 95C in the ad hoc header 95 of the relay Hello frame 90 to a type indicating that the relay flag has been added. Further, the adding unit 88A adds the maximum propagation hop number 96A to the head of the payload 96 in the relay Hello frame 90.

  The wireless communication unit 81 in the processor 74 wirelessly transmits the generated relay Hello frame by broadcast (step S12). The relay unit 6 broadcasts a relay Hello frame after the route to the final destination is established. For example, the wireless communication unit 81 determines whether a response to the relay Hello frame has been received from the communication units 5 around the relay unit 6 (step S13).

  When the control unit 88B in the processor 74 receives a response to the relay Hello frame (Yes at Step S13), the control unit 88B updates the link table 31 regarding the responding communication unit 5 (Step S14). The control unit 88B registers the communication unit 5 that has responded to the adjacent transmission source (LS) 31A, and further registers the link status (weight values such as the return path 31B, the forward path 31C, and the bidirectional 31D), and the link The table 31 is updated. The control unit 88B refers to the adjacent transmission source (LS) in the link table 31 and determines whether or not the number of communication units 5 responding to the relay Hello frame has reached the upper limit value (step S15). Note that the upper limit value can be appropriately changed.

  When the number of communication units 5 responding to the relay Hello frame reaches the upper limit (Yes at Step S15), the control unit 88B stops the broadcast transmission of the relay Hello frame (Step S16), and performs the processing operation illustrated in FIG. finish. As a result, the user can adjust the number of communication units 5 having the relay unit 6 as a relay destination by adjusting the upper limit value.

  Further, when the number of communication units 5 responding to the relay Hello frame has not reached the upper limit value (No at Step S15), the control unit 88B determines whether it is the transmission timing of the relay Hello frame (Step S17). ). In the case of the transmission timing of the relay Hello frame (Yes at Step S17), the adding unit 88A proceeds to Step S11 so as to generate the relay Hello frame.

  If it is not the transmission timing of the relay Hello frame (No at Step S17), the control unit 88B proceeds to Step S13 to determine whether or not a response of the relay Hello frame has been received. If the response of the relay Hello frame has not been received (No at Step S13), the control unit 88B proceeds to Step S15 to determine whether the number of responding communication units 5 has reached the upper limit value. .

  In the route switching request process of FIG. 18, for example, since the newly placed relay unit 6 broadcasts and transmits the relay Hello frame by radio, the route switching to the newly placed relay unit 6 is performed by communication around the relay unit 6. Unit 5 can be requested.

  In addition, since the relay unit 6 adds the maximum propagation hop count 96A in the relay Hello frame, the user can adjust the propagation range of the relay Hello frame by changing the setting of the maximum propagation hop count 96A.

  Further, the relay unit 6 manages the number of communication units 5 responding to the relay Hello frame in the link table 31, and stops the broadcast of the relay Hello frame when the number of communication units 5 reaches the upper limit value. As a result, the user can adjust the load by changing the upper limit value and adjusting the number of communication units 5 for path switching.

  Further, the relay unit 6 periodically continues to broadcast the relay Hello frame when the number of communication units 5 responding to the relay Hello frame has not reached the upper limit value. As a result, the relay unit 6 can continue broadcast transmission of the relay Hello frame until the number of path switching communication units 5 reaches the upper limit value.

  Further, the relay unit 6 stops wireless transmission of the relay Hello frame until a route to the final destination is established. As a result, the relay unit 6 can reliably relay data up to the final destination of the communication unit 5 whose path has been switched.

  When the upper limit value is infinite, broadcast transmission of the relay Hello frame is continued without stopping.

  FIG. 19 is a flowchart showing an example of the processing operation of the processor 55 on the communication unit 5 side involved in the path switching process. The route switching process shown in FIG. 19 is a process of switching and setting the first adjacent destination (LD1) of the final destination in the routing table 32 to the relay unit 6 that has transmitted the relay Hello frame in accordance with the relay Hello frame. .

  In FIG. 19, the radio communication unit 61 in the processor 55 on the communication unit 5 side determines whether or not a relay Hello frame has been received (step S21). When the update unit 68A receives the relay Hello frame (Yes at Step S21), the update unit 68A updates the routing table 32 with the relay unit 6 that has transmitted the relay Hello frame as the first adjacent destination (LD1) of the final destination (GD). (Step S22). As a result, the communication unit 5 has switched the route of the first adjacent destination (LD1) of the final destination (GD) to the relay unit 6.

  The wireless communication unit 61 wirelessly transmits a response to the relay Hello frame to the relay unit 6 that has transmitted the relay Hello frame by unicast (Step S23), and ends the processing operation illustrated in FIG.

  When the wireless communication unit 61 has not received the relay Hello frame (No at Step S21), the wireless communication unit 61 determines whether or not a normal Hello frame has been received (Step S24). When the update unit 68A receives a normal Hello frame (Yes at Step S24), the update unit 68A updates the routing table 32 (Step S25). In addition, the update part 68A updates the evaluation value 32C of the adjacent destination of a Hello frame, when a normal Hello frame is received. The wireless communication unit 61 wirelessly transmits a response to the Hello frame to the unit that has transmitted the Hello frame by unicast (Step S26), and ends the processing operation illustrated in FIG.

  If the wireless communication unit 61 has not received a Hello frame (No at Step S24), the wireless communication unit 61 determines whether a response to the Hello request has been received (Step S27). The Hello request is a frame for confirming the life and death of the opposing unit when a periodic Hello frame cannot be received from the adjacent opposing unit.

  When the update unit 68A receives a response to the Hello request (Yes at Step S27), the update unit 68A updates the routing table 32 (Step S28). The update unit 68A maintains the route information with the relay unit 6 that has transmitted the relay Hello frame in the Hello request response. When the wireless communication unit 61 has not received a response to the Hello request (No at Step S27), the processing operation illustrated in FIG.

  In the path switching process illustrated in FIG. 19, when the communication unit 5 receives the relay Hello frame, the first adjacent destination (LD1) of the final destination is switched to the relay unit 6 that has transmitted the relay Hello frame. As a result, the communication unit 5 can easily switch the route to the relay unit 6 that has transmitted the relay Hello frame.

  FIG. 20 is a flowchart illustrating an example of the processing operation of the processor 55 on the communication unit 5 side related to the relay restriction process. The relay restriction process illustrated in FIG. 20 is a process of restricting relay of a relay Hello frame based on the maximum propagation hop count 96A in the relay Hello frame when a relay Hello frame is received.

  In FIG. 20, the wireless communication unit 61 in the processor 55 on the communication unit 5 side determines whether or not a relay Hello frame has been received (step S41). When receiving the relay Hello frame (Yes at Step S41), the control unit 68B in the processor 55 extracts the maximum propagation hop count 96A in the relay Hello frame (Step S42). Further, the control unit 68B decrements the maximum propagation hop count 96A by −1 (step S43), and determines whether or not the maximum propagation hop count 96A is “1” or more (step S44).

  When the maximum propagation hop count 96A is “1” or more (Yes at Step S44), the control unit 68B rewrites the maximum propagation hop count 96A in the relay Hello frame with the decremented hop count (Step S45). Furthermore, the control unit 68B wirelessly transmits (relays) one relay hop frame with the maximum propagation hop count 96A rewritten (step S46), and ends the processing operation illustrated in FIG. The communication unit 5 that has received the relay Hello frame transmits the relay Hello frame to another communication unit 5.

  Further, when the maximum propagation hop count 96A is not “1” or more (No at Step S44), the control unit 68B prohibits the relay Hello frame from being relayed (Step S47), and ends the processing operation illustrated in FIG. As a result, the communication unit 5 that has received the relay Hello frame prohibits relaying (propagation) to the other communication unit 5 of the relay Hello frame. When the wireless communication unit 61 does not receive the relay Hello frame (No at Step S41), the processing operation illustrated in FIG.

  In the relay restriction process shown in FIG. 20, when the communication unit 5 receives a relay Hello frame, the maximum propagation hop count 96A in the relay Hello frame is extracted. Furthermore, when the communication unit 5 decrements the maximum propagation hop count 96A by −1 and is “1” or more, the relay Hello frame is relayed. As a result, the communication unit 5 that has received the relay Hello frame can relay the relay Hello frame to the adjacent communication unit 5.

  Further, when the communication unit 5 decrements the maximum propagation hop count 96A by −1 and is “0”, the communication unit 5 prohibits the relay Hello frame from being relayed. As a result, the communication unit 5 that has received the relay Hello frame can limit the relay Hello frame relay to the adjacent communication unit 5, that is, the propagation range, based on the maximum propagation hop count 96A.

  FIG. 21 is a flowchart showing an example of the processing operation of the processor 74 on the relay unit 6 side related to the Hello request reception processing. The Hello request receiving process shown in FIG. 21 is a process of updating the link state related to the communication unit 5 in response to the Hello request from the communication unit 5 responding to the relay Hello frame.

  In FIG. 21, the wireless communication unit 81 of the processor 74 on the relay unit 6 side determines whether or not a Hello request has been received from the peripheral communication unit 5 (step S31). Control part 88B determines whether the communication unit 5 which transmitted the Hello request | requirement exists in the adjacent transmission source (LS) in the link table 31, when a Hello request | requirement is received (step S31 affirmation) (step S32). When the control unit 88B is in the adjacent transmission source (LS) in the link table 31 (Yes in step S32), the control unit 88B determines that the communication unit 5 that has requested the Hello is the communication unit 5 that has responded to the relay Hello frame. Then, the wireless communication unit 81 wirelessly transmits the Hello request response to the Hello request communication unit 5 by unicast (Step S33).

  The controller 88B updates the link table 31 (step S34) and ends the processing operation shown in FIG. Note that the control unit 88B maintains route information with the communication unit 5. If the wireless communication unit 81 has not received a Hello request from the peripheral communication unit 5 (No at Step S31), the wireless communication unit 81 ends the processing operation illustrated in FIG. In addition, when the communication unit 5 that has transmitted the Hello request is not in the adjacent transmission source (LS) in the link table 31 (No in Step S32), the control unit 88B performs communication in which the communication unit 5 of the Hello request responds to the relay Hello frame. It is determined that it is not unit 5. Then, the control unit 88B ignores the Hello request and ends the processing operation shown in FIG.

  In the Hello request reception process shown in FIG. 21, it is determined whether or not the relay unit 6 receives the Hello request from the communication unit 5 and the communication unit 5 that has transmitted the Hello request is in the adjacent transmission source 31 </ b> A in the link table 31. To do. When the communication unit 5 from which the relay unit 6 has transmitted the Hello request is in the link table 31, a Hello request response is transmitted to the communication unit 5 that has transmitted the Hello request. As a result, the relay unit 6 can maintain the route information by confirming whether the communication unit 5 responds to the relay Hello frame.

  In the embodiment, the newly arranged relay unit 6 wirelessly transmits the relay Hello frame, and the communication units 5 around the relay unit 6 receive the relay Hello frame. Then, the communication unit 5 that has received the relay Hello frame switches and updates the first adjacent destination (LD1) of the final destination to the relay unit 6 that has transmitted the relay Hello frame. As a result, when a new relay unit 6 is arranged, route switching using the relay unit 6 as a relay route can be performed quickly. That is, the route switching intended by the user can be realized quickly.

  In the embodiment, the newly arranged relay unit 6 wirelessly transmits the relay Hello frame by broadcast. As a result, the communication unit 5 around the relay unit 6 can be requested to switch the route to the newly arranged relay unit 6.

  In addition, since the relay unit 6 adds the maximum propagation hop count 96A in the relay Hello frame, the user can adjust the propagation range of the relay Hello frame by changing the setting of the maximum propagation hop count 96A. That is, the route switching intended by the user can be quickly realized while adjusting the range of the route switching.

  In addition, the relay unit 6 manages the communication unit 5 that responds to the relay Hello frame in the link table 31, and stops the broadcast of the relay Hello frame when the number of responding communication units 5 reaches the upper limit value. As a result, the user can adjust the load by adjusting the number of communication units 5 for path switching by changing the setting of the upper limit value. That is, the user can adjust the load distribution ratio by changing the setting of the upper limit value.

  The relay unit 6 continues broadcasting the relay Hello frame when the number of communication units 5 responding to the relay Hello frame has not reached the upper limit. As a result, the relay unit 6 can continue broadcast transmission of the relay Hello frame until the number of path switching communication units 5 reaches the upper limit value.

  Further, the relay unit 6 stops wireless transmission of the relay Hello frame until a route to the final destination is established. As a result, the relay unit 6 can reliably relay data up to the final destination of the communication unit 5 whose path has been switched.

  Further, in the embodiment, the case where the relay unit 6 is newly arranged in the communication system 1 has been described as an example. However, using the relay unit 6, for example, distribution of communication load in the communication system 1, communication This is useful for clearing the path during unit maintenance.

  In the above embodiment, the relay unit 6 is exemplified as a unit that transmits the relay Hello frame. However, the relay unit 6 is not limited to the relay unit 6 and may be the communication unit 5 or the like.

  Moreover, in the said Example, although the communication unit 5 was illustrated as a unit which receives a relay Hello frame, it is not limited to the communication unit 5, The relay unit 6 grade | etc., May be sufficient.

  In addition, when the communication unit 5 receives a plurality of relay Hello frames, the communication unit 5 updates the unit that has transmitted the frame to the first adjacent destination of the final destination based on the first received frame, and receives the second and subsequent times. The relay Hello frame may be invalidated. In this case, the disturbance at the time of path switching in the communication system 1 can be minimized.

  Further, in the above embodiment, the path switching is realized by switching the unit that has transmitted the relay Hello frame to the first adjacent destination (LD1) of the final destination of the routing table in the communication unit 5 that has received the relay Hello frame. did. However, instead of directly switching the first adjacent destination (LD1), the evaluation value of the communication unit 5 that transmitted the relay Hello frame is adjusted to make the evaluation value of the adjacent destination of the final destination the highest, and the route switching is performed. It may be realized.

  Moreover, in the said Example, when all the communication units 5 in the communication system 1 received the relay Hello frame, the 1st adjacent destination of the last destination was switched and changed. However, in the case of a communication system in which communication units that do not understand the relay Hello frame are mixed, it is possible to change the switching in units of the communication units 5 that understand the relay Hello frame.

  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. 22 is an explanatory diagram illustrating an example of a communication device that executes a route switching program.

  The communication device 100 that executes the path switching program illustrated in FIG. 22 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 in an autonomous multi-hop format. The processor 114 controls the entire communication device 100.

  The ROM 113 stores in advance a path switching program that exhibits the same function as in the above embodiment. Note that the path switching 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. 22, the route switching program includes a determination program 113A, an update program 113B, and a control program 113C. Note that the programs 113A to 113C may be integrated or distributed as appropriate.

  Then, the processor 114 reads these programs 113A to 113C from the ROM 113, and executes each of the read programs. Then, as shown in FIG. 22, the processor 114 functions as the determination process 114A, the update process 114B, and the control process 114C with respect to each program 113A to 113C. The RAM 112 stores a relay destination of data to the destination for each destination.

  The processor 114 determines whether or not a frame to which the relay flag and the maximum number of propagation hops are added is received from another communication device. When the processor 114 receives the frame, the processor 114 updates the RAM 112 so that the communication apparatus that has transmitted the frame becomes the highest priority relay destination of the destination. Furthermore, when the frame is received, the processor 114 controls radio transmission of the frame based on the maximum number of propagation hops in the frame. As a result, each communication device 100 can quickly realize the path switching intended by the user while adjusting the range of path switching.

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

(Appendix 1) A communication system having a plurality of communication devices connected by autonomous multi-hop communication,
Of the plurality of communication devices, the first communication device is:
A communication unit that transmits a frame to which a relay flag and the number of propagation hops are added;
Of the plurality of communication devices, the second communication device is:
For each destination, a storage unit that stores a relay destination of data to the destination;
A communication unit that refers to the storage unit and transmits data to a relay destination corresponding to the destination;
An update unit that updates the storage unit so that, when the frame is received from the first communication device, the first communication device that has transmitted the frame becomes the highest priority relay destination of the destination;
And a control unit that controls transmission of the frame based on the number of propagation hops in the frame when the frame is received from the first communication device.

(Supplementary Note 2) The first communication device is
After transmitting the frame by the communication unit, when a response to the frame is received from the second communication device, a link state with the second communication device for each second communication device that has responded A link storage unit for storing
When the number of the second communication devices stored in the link storage unit reaches the upper limit number, the additional storage to the link storage unit of the responding second communication device is stopped, and the frame The communication system according to supplementary note 1, further comprising: a control unit that causes the communication unit to stop transmission.

(Appendix 3) The update unit
When the plurality of frames are received, the storage unit is updated based on the first received frame so that the first communication device that has transmitted the frame becomes the highest priority relay destination of the destination, and 2 The communication system according to appendix 1 or 2, wherein frames received after the first time are invalidated.

(Supplementary Note 4) The second communication device is
A third communication device that updates the storage unit so that when the frame is received from the first communication device, the first communication device becomes the highest priority relay destination of the destination;
A fourth communication device that calculates the evaluation value of the destination relay destination of the first communication device and updates the storage unit when the frame is received from the first communication device. The communication system according to any one of appendices 1 to 3, characterized by:

(Supplementary Note 5) The communication unit in the first communication device is:
The communication system according to any one of appendices 1 to 4, wherein transmission of the frame is stopped until a path with the destination communication device is established.

(Appendix 6) The storage unit
For each destination, store the relay destination and an evaluation value for selecting the relay destination,
The update unit
Evaluation value corresponding to the first communication device as the relay destination so that the first communication device becomes the highest priority relay destination of the destination when the frame is received from the first communication device. The communication system according to any one of appendices 1 to 5, wherein the storage unit is updated by adjusting

(Appendix 7) A communication unit that communicates by an autonomous multi-hop method;
For each destination, a storage unit that stores a relay destination of data to the destination;
A control unit that controls the communication unit to transmit data to a relay destination corresponding to the destination with reference to the storage unit;
When receiving a frame with a relay flag and the number of propagation hops from another communication device, the update unit updates the storage unit so that the communication device that has transmitted the frame becomes the highest priority relay destination of the destination When,
And a control unit that controls transmission of the frame based on the number of propagation hops in the frame when the frame is received from the other communication device.

(Appendix 8) The update unit
When the plurality of frames are received, the storage unit is updated based on the first received frame so that the communication device that has transmitted the frame becomes the highest priority relay destination of the destination, and the second and subsequent times. The communication apparatus according to appendix 7, wherein the received frame is invalidated.

(Supplementary Note 9) The storage unit
For each destination, store the relay destination and an evaluation value for selecting the relay destination,
The update unit
When the frame is received, the storage unit is updated by adjusting the evaluation value of the communication device as the relay destination so that the communication device that has transmitted the frame is selected as the highest priority relay destination of the destination The communication apparatus according to appendix 7 or 8, characterized in that.

(Additional remark 10) The communication part which communicates by an autonomous multihop system,
An adding unit for adding a relay flag and the number of propagation hops in the frame;
After transmitting the frame to which the relay flag and the number of propagation hops are added by the communication unit, if a response to the frame is received from another communication device, the communication device A link storage unit for storing a link state with
When the number of the communication devices stored in the link storage unit reaches the upper limit number, the additional storage to the link storage unit of the responding communication device is stopped, and the transmission of the frame is performed in the communication unit And a control unit for stopping the communication device.

(Supplementary Note 11) The communication unit
11. The communication apparatus according to appendix 10, wherein transmission of the frame to which the relay flag is added is stopped until a path with a final destination communication apparatus is established.

(Supplementary note 12) A path switching method of a communication system having a plurality of communication devices connected by autonomous multi-hop communication,
Of the plurality of communication devices, the first communication device is:
Send a frame with relay flag and propagation hop count added,
Of the plurality of communication devices, the second communication device is:
A storage that stores a relay destination of data for each destination so that when the frame is received from the first communication device, the first communication device that has transmitted the frame becomes the highest priority relay destination of the destination Update the department,
When the frame is received from the first communication device, each path switching method is configured to execute each process for controlling transmission of the frame based on the number of propagation hops in the frame.

(Supplementary note 13) A path switching program executed by a communication device including a communication unit that communicates by an autonomous multi-hop method, a storage unit that stores a relay destination of data to the destination for each destination, and a processor There,
In the processor,
Determine whether or not a frame with a relay flag and the number of propagation hops is received from another communication device,
When the frame is received, the storage unit is updated so that the communication device that has transmitted the frame becomes the highest priority relay destination of the destination, and when the frame is received, the number of propagation hops in the frame Based on the above, a path switching program characterized by causing each process to control transmission of the frame to be executed.

DESCRIPTION OF SYMBOLS 1 Communication system 5 Communication unit 6 Relay unit 31 Link table 32 Routing table 32A Final destination 32B Adjacent destination 32C Evaluation value 61 Wireless communication part 68A Update part 68B Control part 81 Wireless communication part 88A Addition part 88B Control part 100 Communication apparatus 111 Communication interface 112 RAM
113 ROM
114 processor 114A determination process 114B update process 114C control process

Claims (10)

A communication system having a plurality of communication devices connected by autonomous multi-hop communication,
Of the plurality of communication devices, the first communication device is:
A communication unit that transmits a frame to which a relay flag and the number of propagation hops are added;
Of the plurality of communication devices, the second communication device is:
For each destination, a storage unit that stores a relay destination of data to the destination;
A communication unit that refers to the storage unit and transmits data to a relay destination corresponding to the destination;
An update unit that updates the storage unit so that, when the frame is received from the first communication device, the first communication device that has transmitted the frame becomes the highest priority relay destination of the destination;
And a control unit that controls transmission of the frame based on the number of propagation hops in the frame when the frame is received from the first communication device. The first communication device is:
After transmitting the frame by the communication unit, when a response to the frame is received from the second communication device, a link state with the second communication device for each second communication device that has responded A link storage unit for storing
When the number of the second communication devices stored in the link storage unit reaches the upper limit number, the additional storage to the link storage unit of the responding second communication device is stopped, and the frame The communication system according to claim 1, further comprising: a control unit that causes the communication unit to stop transmission. The update unit
When the plurality of frames are received, the storage unit is updated based on the first received frame so that the first communication device that has transmitted the frame becomes the highest priority relay destination of the destination, and 2 3. The communication system according to claim 1, wherein frames received after the first time are invalidated. The second communication device is:
A third communication device that updates the storage unit so that when the frame is received from the first communication device, the first communication device becomes the highest priority relay destination of the destination;
A fourth communication device that calculates the evaluation value of the destination relay destination of the first communication device and updates the storage unit when the frame is received from the first communication device. The communication system according to any one of claims 1 to 3. The communication unit in the first communication device is:
5. The communication system according to claim 1, wherein transmission of the frame is stopped until a path with the destination communication apparatus is established. The storage unit
For each destination, store the relay destination and an evaluation value for selecting the relay destination,
The update unit
Evaluation value corresponding to the first communication device as the relay destination so that the first communication device becomes the highest priority relay destination of the destination when the frame is received from the first communication device. The communication system according to claim 1, wherein the storage unit is updated by adjusting the value. A communication unit that communicates by an autonomous multi-hop method;
For each destination, a storage unit that stores a relay destination of data to the destination;
A control unit that controls the communication unit to transmit data to a relay destination corresponding to the destination with reference to the storage unit;
When receiving a frame with a relay flag and the number of propagation hops from another communication device, the update unit updates the storage unit so that the communication device that has transmitted the frame becomes the highest priority relay destination of the destination When,
And a control unit that controls transmission of the frame based on the number of propagation hops in the frame when the frame is received from the other communication device. A communication unit that communicates by an autonomous multi-hop method;
An adding unit for adding a relay flag and the number of propagation hops in the frame;
After transmitting the frame to which the relay flag and the number of propagation hops are added by the communication unit, if a response to the frame is received from another communication device, the communication device A link storage unit for storing a link state with
When the number of the communication devices stored in the link storage unit reaches the upper limit number, the additional storage to the link storage unit of the responding communication device is stopped, and the transmission of the frame is performed in the communication unit And a control unit for stopping the communication device. A path switching method for a communication system having a plurality of communication devices connected by autonomous multi-hop communication,
Of the plurality of communication devices, the first communication device is:
Send a frame with relay flag and propagation hop count added,
Of the plurality of communication devices, the second communication device is:
A storage that stores a relay destination of data for each destination so that when the frame is received from the first communication device, the first communication device that has transmitted the frame becomes the highest priority relay destination of the destination Update the department,
When the frame is received from the first communication device, each path switching method is configured to execute each process for controlling transmission of the frame based on the number of propagation hops in the frame. A path switching program executed by a communication device including a communication unit that communicates by an autonomous multi-hop method, a storage unit that stores a relay destination of data to the destination for each destination, and a processor,
In the processor,
Determine whether or not a frame with a relay flag and the number of propagation hops is received from another communication device,
When the frame is received, the storage unit is updated so that the communication device that has transmitted the frame becomes the highest priority relay destination of the destination,
A path switching program that, when receiving the frame, causes each process to control transmission of the frame based on the number of propagation hops in the frame.

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