JP2015179898A - Radio device, radio system, and radio method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to re-construct a communication path from a radio device situated at a reference point of a communication path using a radio device in the vicinity of a movement destination.SOLUTION: Each node includes a first determination unit, a third determination unit, and a transition unit. The first determination unit determines whether or not a node including itself belongs to nodes on a main route in an ad-hoc network on the basis of data traffic flowing through the node on the ad-hoc network. The transition unit receives a hello packet for a sleep instruction from another node, and shifts the node to a sleep state if it is determined that the node does not belong to the nodes on the main route. The third determination unit receives a hello packet for a wake-up instruction from a reference point node which detected reference point change of the main route, and determines whether the number of hops at this time of the hello packet for the wake-up instruction to the node in the sleep state is less than the number of hops at the previous time. The transition unit cancels the sleep state of the node if the number of hops at this time is less than the number of hops at the previous time.

Description

  The present invention relates to a wireless device, a wireless system, and a wireless method.

  An ad hoc network is a wireless data communication network having a plurality of independent nodes. In an ad hoc network, even if there is no device for controlling the entire network, each node can cooperate with each other to construct an independent network. For example, when transmitting a packet from a transmitter in an ad hoc network to a receiver, each node between the transmitter and the receiver becomes a repeater. Each node can transmit a packet from the transmitter to the receiver by transferring the packet wirelessly to an adjacent node and repeating the packet transfer in a relay format.

  Nodes used for ad hoc networks include, for example, a wide range of devices such as electrical appliances, mobile terminals, and automobiles. As a result, for example, even in an area with a small number of base stations, a unique network can be constructed, and in the event of a disaster, a network can be constructed by peripheral devices communicating wirelessly.

  Each node generates a routing table in order to construct an ad hoc network with neighboring neighboring nodes. In the routing table, for example, a global destination (GD) and a local destination (LD) when a packet is transmitted from the transmitter to the receiver are stored in association with each other. GD is the receiver's destination. The LD is a destination of a repeater that transfers when a packet is transmitted to the receiver.

  In each node, a plurality of repeater addresses to be transferred when transmitting to the receiver are set in the routing table, and the priority order is set in descending order of communication quality for each repeater. For example, in a normal time, a node refers to a routing table and transfers a packet to a transfer destination node that is a relay with the highest priority. However, when a failure occurs in the transfer destination node and communication becomes impossible, the node refers to the routing table, searches for a transfer destination node with the next highest priority, and transfers the packet to the searched transfer destination node. As a result, a network that is resistant to failures can be constructed.

  In ad-hoc networks, not only nodes belonging to the main route and sub-routes that become detour routes when sending packets from the transmitter to the receiver, but also unused nodes that do not belong to these routes. Activated. As a result, wasteful power is applied to unused nodes in the ad hoc network.

  Therefore, among the nodes in the ad hoc network, the nodes belonging to the main route and the sub route are set in an active state, and the unused nodes not belonging to the main route and the sub route are set in a sleep state in a power saving state. As a result, it is possible to suppress wasteful power for unused nodes in the ad hoc network.

JP 2011-254409 A

  However, for example, when the base node at the base point of the route moves to the vicinity of the sleep state node at the destination, the base node cannot communicate with the nodes around the destination because the nodes around the destination are in the sleep state. As a result, the route cannot be reconstructed from the base point node using the nodes around the destination.

  In one aspect, an object of the present invention is to provide a wireless device, a wireless system, and a wireless method capable of reconstructing a communication path from a node at a base point of the communication path using nodes around the destination.

  In one aspect, the wireless device includes a first determination unit, a transition unit, a second determination unit, and a release unit. The first determination unit determines whether or not the own device belongs to a wireless device on a communication path in the ad hoc network based on a communication amount passing through the own device on the ad hoc network. The transition unit receives the first signal from the first wireless device, and transitions the own device to a power saving state when it is determined that the own device does not belong to the wireless device on the communication path. When the second determination unit receives the second signal from the wireless device that has detected the base point change of the communication path, the second determination unit determines that the second signal has a hop count of the second signal in the self-powered device. It is determined whether it is less than the hop count of the previous signal received before reception. A cancellation | release part cancel | releases the power saving state of the said own apparatus, when the hop number of a 2nd signal is less than the hop number of a last signal in a 2nd determination part.

  As one aspect, the communication path can be reconstructed from the wireless apparatus at the base point of the communication path using wireless apparatuses around the destination.

FIG. 1 is an explanatory diagram illustrating an example of a wireless system of an ad hoc network according to the present embodiment. FIG. 2 is an explanatory diagram showing an example of a wireless system at the time of building a main route. FIG. 3 is an explanatory diagram showing an example of a wireless system at the time of subroute construction. FIG. 4 is an explanatory diagram illustrating an example of a wireless system at the time of transmitting a hello packet for a sleep instruction. FIG. 5 is an explanatory diagram illustrating an example of a wireless system when sleep is set. FIG. 6 is an explanatory diagram illustrating an example of a wireless system when the base point of the main route is changed. FIG. 7 is an explanatory diagram illustrating an example of a wireless system at the time of transmitting a Hello packet including a wakeup instruction after changing the base point. FIG. 8 is an explanatory diagram showing an example of a wireless system at the time of reconstructing the main route after changing the base point. FIG. 9 is an explanatory diagram illustrating an example of a wireless system at the time of sub-route reconstruction after a base point change. FIG. 10 is an explanatory diagram illustrating an example of a wireless system at the time of transmitting a Hello packet of a sleep instruction after changing the base point. FIG. 11 is an explanatory diagram illustrating an example of a wireless system at the time of sleep setting after changing the base point. FIG. 12 is a block diagram illustrating an example of a node. FIG. 13 is an explanatory diagram illustrating an example of a routing table. FIG. 14 is an explanatory diagram illustrating an example of a condition table. FIG. 15 is an explanatory diagram illustrating an example of a format configuration of a Hello packet. FIG. 16 is a flowchart illustrating an example of the processing operation of the control unit in the node related to the active transition process. FIG. 17 is a flowchart illustrating an example of the processing operation of the control unit in the node related to the sleep transition process. FIG. 18 is an explanatory diagram illustrating an example of a hardware configuration of a node. FIG. 19 is an explanatory diagram illustrating an example of a hardware configuration of the GW.

  Hereinafter, embodiments of a wireless device, a wireless system, and a wireless method disclosed in the present application will be described in detail based on the drawings. The disclosed technology is not limited by the present embodiment. The following embodiments may be appropriately combined.

  FIG. 1 is an explanatory diagram illustrating an example of a wireless system of an ad hoc network according to the present embodiment. An ad hoc network wireless system 10 illustrated in FIG. 1 includes a plurality of nodes 100 and performs wireless communication between the nodes 100. In addition to the plurality of nodes 100, the wireless system 10 includes a transmitter 11 that transmits a packet, a receiver 12 that receives a packet transmitted from the transmitter 11, and a gateway (hereinafter, simply referred to as a receiver 12). (Referred to as GW) 101. The transmitter 11 corresponds to, for example, a camera that acquires a moving image of a subject, and the receiver 12 corresponds to, for example, a recorder that records the moving image acquired by the camera.

  Each node 100 on the route that is a communication path between the transmitter 11 and the receiver 12 repeats packet transfer of the packet received from the transmitter 11 to the adjacent node 100 by the wireless relay method. Is sent to the receiver 12. For example, the node 100A that has received the packet from the transmitter 11 transfers the packet to the adjacent nodes 100b1, 100B, and 100b2, for example. For convenience of explanation, when one node in the figure is shown, it is described by adding a symbol indicating each node in the figure to the end of “node 100”. For example, when referring to the node “e1” illustrated in FIG. 1, the node is represented as “node 100 e1”. In addition, the node 100B that has received the packet from the node 100A transfers the packet to adjacent nodes 100b1, 100C, and 100b2, for example. The other nodes 100 that have received the packet also transfer the packet to the adjacent node 100 in the same manner.

  In the wireless system 10, a main route and a sub route for transmitting a packet from the transmitter 11 to the receiver 12 are set. The main route is used as a main route when transmitting a packet from the transmitter 11 to the receiver 12.

  FIG. 2 is an explanatory diagram showing an example of the wireless system 10 when the main route is constructed. Each node 100 in the wireless system 10 shown in FIG. 2 monitors the data traffic amount of the own node 100, and determines that the own node 100 belongs to the main route when the data traffic amount is equal to or larger than the threshold, and sets the main route as the main route. To do. The wireless system 10 sets the route having the largest data traffic volume among a plurality of routes, for example, the route of node 100A → node 100B → node 100C → node 100D → node 100E → node 100F → GW 101 as the main route. As a result, the wireless system 10 can construct a main route between the transmitter 11 and the receiver 12.

  Further, the wireless system 10 sets a sub route as a backup route for the main route. The sub route is used as a backup route when the main route cannot be used due to a failure of the node 100 on the main route or the occurrence of congestion of load concentration on the main route.

  FIG. 3 is an explanatory diagram illustrating an example of the wireless system 10 at the time of constructing a subroute. As shown in FIG. 3, the node 100A belonging to the main route transmits a Hello packet including a route state flag to be described later to the transfer destination node 100b1. The route status flag is main route information for identifying whether or not the own node is a main route, and subroute information for identifying whether or not the own node is a sub route. The node 100b1 determines whether or not the own node belongs to the sub-route based on the sub-route information and the LD information of the route state flag in the Hello packet received from the node 100A. Note that the node 100b1 determines that the own node belongs to the sub-route because the own node is included in the LD information. Similarly, the node 100A transmits the Hello packet including the route state flag to the other transfer destination nodes 100B and 100b2.

  In addition, the node 100b1 transmits a Hello packet including a route state flag to the node 100c1, the node 100H, and the node 100I. The node 100c1 determines whether or not the own node belongs to the sub-route based on the route status flag and LD information in the received Hello packet. Note that the node 100c1 determines that the own node belongs to the sub-route because the own node is included in the LD information. On the other hand, the node 100H and the node 100I determine that the own node does not belong to the main route and the sub route based on the route state flag and the LD information in the received Hello packet. The node 100H and the node 100I determine that the own node does not belong to either the main route or the sub route when the own node is not included in the LD information. In addition, when transmitting a Hello packet, the node 100 that does not belong to either the main route or the sub route transmits a route state flag, LD1 information, LD2 information, and LD3 information to the transfer destination node 100 in an unset state.

  Each of the nodes 100B to 100F belonging to the main route also transmits a Hello packet including a route state flag to the transfer destination node 100. Each node 100 that receives the Hello packet further transmits the Hello packet to the transfer destination node 100. Then, each node 100 that has received the Hello packet determines whether or not the node belongs to the sub-route based on the route state flag and LD information in the Hello packet. Each node 100 sets a sub-route between the transmitter 11 and the receiver 12 when determining that the node belongs to the sub-route.

  Then, the wireless system 10 sets the route of the node 100b1, the node 100c1, the node 100d1, the node 100e1, the node 100f1, and the GW 101 as a sub route. Further, the wireless system 10 sets the route of the node 100b2, the node 100c2, the node 100d2, the node 100e2, the node 100f2, and the GW 101 as a sub route. As a result, the wireless system 10 can construct two sub-routes between the transmitter 11 and the receiver 12.

  FIG. 4 is an explanatory diagram illustrating an example of the wireless system 10 when a sleep instruction Hello packet is transmitted. The radio system 10 illustrated in FIG. 4 constructs one main route and two sub-routes between the transmitter 11 and the receiver 12.

  The GW 101 receives the Hello packet including the main route information and the sub route information, and determines whether or not the current main route information and the sub route information are different from the previous main route information and the sub route information. When the current main route information and sub-route information are different from the previous main route information and sub-route information, the GW 101 requests each node 100 to broadcast a sleep instruction Hello packet. The node 100 such as the node 100H or the node 100I that does not belong to either the main route or the sub route shifts from the active state to the sleep state when receiving the sleep instruction Hello packet. Note that the sleep state means a so-called cold standby state, which is a power saving state that saves power compared to the active state and can be started up faster than when shut down.

  FIG. 5 is an explanatory diagram illustrating an example of the wireless system 10 when sleep is set. When receiving the Hello packet from the node 100 belonging to the main route, the GW 101 illustrated in FIG. 5 requests each node 100 to broadcast the Hello packet for the sleep instruction. For example, since the node 100A, the node 100B, the node 100b1, the node 100b2, the node 100c1, and the like belong to the main route or the sub route, the normal active state is maintained when the sleep instruction Hello packet is received. On the other hand, since the node 100H, the node 100I, and the like do not belong to either the main route or the sub route, the node 100H, the node 100I, and the like shift to the sleep state when receiving the sleep instruction Hello packet. For example, the node 100M, the node 100N, the node 100O, the node 100P, the node 100Q, the node 100R, the node 100S, the node 100H, the node 100I, the node 100J, the node 100K, and the node 100L are in the sleep state. As a result, the wireless system 10 can suppress useless power consumption by suppressing the power consumption of the node 100 that does not belong to either the main route or the sub route.

  FIG. 6 is an explanatory diagram illustrating an example of the wireless system 10 when the base point of the main route is changed. Assume that the transmitter 11 and the node 100A serving as the base points on the main route between the transmitter 11 and the receiver 12 in the wireless system 10 illustrated in FIG. 6 have moved to the vicinity of the node 100N in the sleep state. As a result, since the base node 100A cannot periodically receive the Hello packet from the adjacent node 100B on the main route, the base point node 100A detects the base point change on the main route. When the base point change is detected, the base point node 100A transmits a wake-up instruction Hello packet to the movement destination nodes, for example, the node 100M, the node 100N, and the node 100O.

  FIG. 7 is an explanatory diagram illustrating an example of the wireless system 10 when transmitting a Hello packet for a wake-up instruction after changing the base point of the main route. When the node 100N illustrated in FIG. 7 receives a Hello packet for a wakeup instruction, the node 100N determines whether or not the node satisfies a predetermined condition described later. When the node 100N satisfies a predetermined condition, the node 100N shifts from the sleep state to the active state. Further, when the node 100M does not satisfy the predetermined condition, the node 100M continues the currently set state, for example, the sleep state. When the node 100N shifts from the sleep state to the active state, the node 100N transmits a wake-up instruction Hello packet to the transfer destination node 100, for example, the node 100b2, the node 100c2, and the node 100O. The wireless system 10 repeats these processing operations, and shifts the node 100 in the sleep state to the active state. As a result, the wireless system 10 shifts to an active state in which all nodes 100 on the route when transmitting a packet from the transmitter 11 to the receiver 12 can communicate.

  FIG. 8 is an explanatory diagram illustrating an example of the wireless system 10 when the main route is reconstructed after changing the base point. Each node 100 in the wireless system 10 shown in FIG. 8 monitors the data traffic volume of the own node, and determines that the own node belongs to the main route when the data traffic volume is equal to or greater than the threshold, and sets the node as the main route. . For example, the radio system 10 sets the route of the node 100A → the node 100N → the node 100c2, the node 100d2, the node 100e2, the node 100f2, and the GW 101 having the largest data traffic volume as the main route. As a result, the wireless system 10 can reconstruct the main route between the transmitter 11 and the receiver 12.

  FIG. 9 is an explanatory diagram illustrating an example of the wireless system 10 at the time of sub-route reconstruction after a base point change. As shown in FIG. 9, the node 100A belonging to the main route transmits a Hello packet including a route state flag to the transfer destination node 100N. The node 100N determines whether or not the own node belongs to the sub-route based on the sub-route information in the route status flag in the Hello packet received from the node 100A. The node 100N determines that the own node belongs to the sub-route because the own node exists in the sub-route information. Similarly, the node 100A transmits the Hello packet including the route state flag to the other transfer destination nodes 100M and 100O.

  In addition, the node 100N transmits a Hello packet including a route state flag to the nodes 100b2, 100c2, and 100O. The node 100O determines whether or not the own node belongs to the sub-route based on the route state flag and the LD information in the received Hello packet. Note that the node 100O determines that the own node belongs to the sub-route because the own node is included in the LD information. For example, the node 100B and the node 100b1 determine that the own node does not belong to the main route and the sub route when the own node is not included in the LD information.

  Each of the nodes 100c2, 100d2, 100e2, and 100f2 belonging to the main route also transmits a Hello packet including a route state flag to the transfer destination node 100. Then, each node 100 that has received the Hello packet further transmits the Hello packet to the transfer destination node 100. Then, each node 100 that has received the Hello packet determines whether or not the node belongs to the sub-route based on the route state flag and LD information in the Hello packet. Each node 100 sets a sub-route between the transmitter 11 and the receiver 12 when determining that the node belongs to the sub-route.

  Then, the wireless system 10 sets the route of the node 100M → the node 100b2, the node 100C, the node 100D, the node 100E, the node 100F, and the GW 101 as a sub route. Further, the wireless system 10 sets the route of the node 100O → the node 100P → the node 100Q → the node 100R → the node 100S → the GW 101 as a sub route. As a result, the wireless system 10 can reconstruct two sub-routes between the transmitter 11 and the receiver 12.

  FIG. 10 is an explanatory diagram illustrating an example of the wireless system 10 at the time of transmitting a Hello packet of a sleep instruction after changing the base point. The GW 101 illustrated in FIG. 10 receives the Hello packet including the main route information and the sub route information, and determines whether or not the current main route information and the sub route information are different from the previous main route information and the sub route information. When the current main route information and sub-route information are different from the previous main route information and sub-route information, the GW 101 requests each node 100 to broadcast a sleep instruction Hello packet. The node 100 such as the node 100H or the node 100I that does not belong to either the main route or the sub route shifts from the active state to the sleep state when receiving the sleep instruction.

  FIG. 11 is an explanatory diagram illustrating an example of the wireless system 10 at the time of sleep setting after changing the base point. When receiving the Hello packet from the node 100 belonging to the main route, the GW 101 illustrated in FIG. 11 requests each node 100 to broadcast the Hello packet for the sleep instruction. For example, since the node 100A, the node 100N, the node 100M, the node 100O, and the like belong to the main route or the sub route, the normal active state is maintained when the hello packet indicating the sleep instruction is received. On the other hand, for example, since the node 100B, the node 100b1, and the like do not belong to either the main route or the sub route, when the Hello packet for the sleep instruction is received, the node 100B and the node 100b1 shift to the sleep state. For example, the node 100B, the node 100b1, the node 100c1, the node 100d1, the node 100e1, the node 100f1, the node 100H, the node 100I, the node 100J, the node 100K, and the node 100L are in the sleep state. As a result, the wireless system 10 can suppress useless power consumption by suppressing the power consumption of the node 100 that does not belong to either the main route or the sub route.

  FIG. 12 is a block diagram illustrating an example of the node 100. A node 100 illustrated in FIG. 12 includes a communication I / F 110, a control unit 120, and a storage unit 130. The communication I / F 110 is an interface that manages wireless communication with other nodes 100. The storage unit 130 includes a flag storage unit 131, a routing table 132, a condition table 133, and a previous storage unit 134. The flag storage unit 131 is an area for storing a flag indicating whether or not the own node belongs to the main route or the sub route based on the route state flag and the LD information in the Hello packet.

  The routing table 132 is an area in which the address 132C and the communication quality priority 132D are stored in association with each LD 132B of the GD 132A. FIG. 13 is an explanatory diagram showing an example of the routing table 132. The routing table 132 illustrated in FIG. 13 exemplifies the routing table 132 of the node 100A illustrated in FIG. 3, for example, and the destination (address) of the GW 101 connected to the receiver 12 is stored in the GD 132A. For example, the nodes 100B, 100b1, and 100b2 are stored in the LD 132B as destinations of the transfer destination node 100. Further, for each transfer destination node 100 of the LD 132B, an address 132C and a communication quality priority 132D are stored in association with each other. The control unit 120 refers to the routing table 132, and recognizes, for example, that the communication quality priority 132D is the first when transmitting a packet from the node 100A to the node 100B. Further, the control unit 120 recognizes that the communication quality priority 132D when the packet is transmitted from the node 100A to the node 100b1 is second. The control unit 120 recognizes that the communication quality priority 132D when transmitting a packet from the node 100A to the node 100b2 is the third place.

  FIG. 14 is an explanatory diagram showing an example of the condition table 133. The condition table 133 illustrated in FIG. 14 stores an instruction name 133A, an issue time 133B, a hop count 133C, a received electric field strength 133D, and an operation content 133E in association with each other. The instruction name 133A is, for example, an instruction name that identifies a wake-up instruction. The issue time 133B is a condition of issue time to be compared with the issue time of the Hello packet received this time. The hop count 133C is a condition for the hop count to be compared with the hop count of the currently received Hello packet. The received electric field strength 133D is a condition of the received electric field strength to be compared with the received electric field strength of the Hello packet received this time. The operation content 133E is an operation content executed by the own node. The previous storage unit 134 is an area for storing previous information such as the issuance time, number of hops, received electric field strength, main route information, and sub route information of the previously received Hello packet. The storage unit 130 corresponds to, for example, a semiconductor memory device such as a random access memory (RAM), a read only memory (ROM), and a flash memory, and a storage device such as a hard disk or an optical disk.

  FIG. 15 is an explanatory diagram illustrating an example of a format configuration of a Hello packet. The Hello packet 140 shown in FIG. 15 includes a Hello message header 141, a Hello header 142, a route state flag 143, an issue time 144, a hop count 145, LD1 information 146A, LD2 information 146B, and LD3 information 146C. Have The Hello message header 141 is information for identifying the transfer source node 100 of the Hello packet. The Hello header 142 is information regarding communication quality for each route to the GW 101 as viewed from the transfer source node 100 of the Hello packet. The route status flag 143 is main route information and sub route information for identifying whether the node 100 is a main route or a sub route. Further, the route state flag 143 is information for identifying a wake-up instruction or a sleep instruction Hello packet.

  The issue time 144 is the issue time when the Hello packet is issued. The number of hops 145 is the number of transfers of the node to which the Hello packet is transferred, that is, the number of hops. The LD1 information 146A is information indicating the address of the node 100 having the highest communication quality from the viewpoint of the transfer source node 100. The LD2 information 146B is information indicating the address of the node 100 having the second highest communication quality from the viewpoint of the transfer source node 100. The LD3 information 146C is information indicating the address of the node 100 having the third highest communication quality from the viewpoint of the transfer source node 100.

  The control unit 120 illustrated in FIG. 12 includes a reception unit 121, a first determination unit 122, a second determination unit 123, a detection unit 124, a third determination unit 125, a generation unit 126, and a transmission unit. 127 and a transition unit 128. The function of the control unit 120 can be realized by an integrated circuit such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). Further, the function of the control unit 120 can be realized by, for example, a CPU (Central Processing Unit) executing a predetermined program.

  The receiving unit 121 receives a Hello packet transmitted from the transfer source node 100 and a Hello packet for a sleep instruction or a wake-up instruction.

  The first determination unit 122 constantly monitors the amount of data traffic to the own node in the wireless system 10, and determines that the own node belongs to the main route when the amount of data traffic in the own node is equal to or greater than a threshold. When determining that the own node belongs to the main route, the first determination unit 122 stores the main route flag ON in the flag storage unit 131.

  The second determination unit 123 confirms whether the transfer source node 100 belongs to the main route or the sub route based on the route state flag 143 in the Hello packet 140. Also, the second determination unit 123 confirms the LD1 information 146A, LD2 information 146B, and LD3 information 146C in the Hello packet 140, and determines whether or not the priority of the communication quality of the packet as viewed from the transfer source is within the top three. To check. The second determination unit 123 determines whether or not the own node belongs to the sub-route based on the route state flag 143 and the LD information 146A to 146C in the Hello packet 140. When the second determination unit 123 determines that the own node belongs to the sub route, the second determination unit 123 stores the sub route flag ON in the flag storage unit 131. Note that the Hello packet 140 may include information with the communication quality priority of the fourth and higher ranks as LD information.

  The generation unit 126 refers to the routing table 132 and generates a Hello packet in which the addresses of the nodes 100 whose communication quality priorities are first to third are set in the LD1 information 146A, the LD2 information 146B, and the LD3 information 146C. To do.

  The transmission unit 127 transmits a Hello packet including information such as the route state flag 143 and the LD information 146A to 146C to each transfer destination node 100 via the communication I / F 110 in order to set a sub route in the wireless system 10. . In addition, the transmission part 125 may set the timing which transmits a Hello packet using a random function.

  When the local node 100 does not belong to either the main route or the sub-route and receives a sleep instruction Hello packet, the transition unit 128 transitions the local node to the sleep state. The GW 101 receives the main route information and the sub route information. When the received main route information and the sub route information are different from the previous information, the GW 101 requests each node 100 to broadcast the Hello packet including the sleep instruction. When the receiving unit 121 receives a hello packet indicating a sleep instruction, the transition unit 128 refers to the flag storage unit 131 and determines whether the node belongs to the main route or the sub route based on ON / OFF of the main route flag or the sub route flag. Confirm. When the node belongs to the main route or the sub route, the transition unit 128 continues the normal active state. In addition, when the own node does not belong to either the main route or the sub route, the transition unit 128 causes the own node to transition to the sleep state.

  The detection unit 124 determines whether or not a change in the base point of the main route due to the movement of the node 100 has been detected. The base point change on the main route is, for example, a case where the own node 100A serving as the base point of the main route shown in FIG. When the node 100A is a base node on the main route, the detection unit 124 determines whether or not a Hello packet from the adjacent node 100B on the main route is periodically received. When the detection unit 124 periodically receives a Hello packet from the adjacent node 100B on the main route, the detection unit 124 determines that communication is being performed on the main route. Moreover, the detection part 124 determines with having detected the base point change on a main route, when the Hello packet from the adjacent node 100B is not received regularly. When the detecting unit 124 detects the base point change, the transmitting unit 127 transmits a wake-up instruction Hello packet to the adjacent peripheral node 100.

  When the node 100 is in the sleep state, the third determination unit 125 determines whether or not the reception unit 121 has received a wake-up instruction Hello packet from another node 100. The third determination unit 125 refers to the condition table 133 and the previous storage unit 134 when a Hello packet for a wake-up instruction is received. The third determination unit 125 determines whether or not the current issue time, the current number of hops, the current received electric field strength, and the like in the Hello packet of the wake-up instruction received by the reception unit 121 satisfy predetermined conditions in the condition table 133. Determine whether.

  The third determination unit 125 refers to the condition table 133 and determines whether or not the current issue time is newer than the previous issue time stored in the previous storage unit 134. When the current issue time is newer than the previous issue time, the third determination unit 125 refers to the condition table 133 and determines whether or not the current hop count satisfies a predetermined hop condition.

  For example, when the number of current hops is greater than the number of previous hops stored in the previous storage unit 134 as the predetermined hop condition, the third determination unit 125 determines that the operation content is the continuation of the sleep state. Further, as the predetermined hop condition, for example, when the number of current hops is smaller than the number of previous hops stored in the previous storage unit 134, the third determination unit 125 determines that the operation content shifts to the active state. To do. As the predetermined hop condition, for example, the third determination unit 125 has the same number of current hops as the previous number of hops stored in the previous storage unit 134 and the current received electric field strength is less than the previous received electric field strength. In this case, it is determined that the sleep state is continued as the operation content. For example, when the current hop count is the same as the previous hop count and the current received electric field strength is greater than or equal to the previous received electric field strength, the third determining unit 125 is in an active state as the predetermined hop condition. It is determined to move to. If the current issue time is not newer than the previous issue time, the third determination unit 125 determines that the sleep state is continued as the operation content.

  When the third determination unit 125 determines that the sleep state is continued, the transition unit 128 continues the sleep state. The transition unit 128 transitions from the sleep state to the active state when the third determination unit 125 determines to shift to the active state. As a result, each node 100 in the wireless system 10 can wirelessly communicate with other nodes 100 when the node 100 shifts from the sleep state to the active state.

  Next, the operation of the wireless system 10 of this embodiment will be described. FIG. 16 is a flowchart illustrating an example of a processing operation of the control unit 120 in the node 100 related to the active transition process. The receiving unit 121 in the control unit 120 of the node 100 illustrated in FIG. 16 determines whether a Hello packet for a wake-up instruction has been received (step S11). When the base node 100 on the main route detects a change of the base point of the main route due to the movement of the own node 100, a wake-up instruction Hello packet is transmitted.

  The third determination unit 125 in the control unit 120 determines whether or not the own node 100 is in the sleep state when receiving the Hello packet of the wake-up instruction (Yes in Step S11) (Step S12). When the node 100 is in the sleep state (Yes at Step S12), the third determination unit 125 determines whether or not the current issue time is newer than the previous issue time (Step S13). The current issue time corresponds to the issue time in the Hello packet received in step S11. The previous issue time is the issue time of the previously received Hello packet stored in the previous storage unit 134. The reason for comparing the current issue time with the previous issue time is to prevent frequent switching to the active state or the sleep state simply by receiving the sleep instruction or the wake-up instruction.

  When the current issue time is newer than the previous issue time (Yes at Step S13), the third determination unit 125 determines whether the current hop number is equal to or less than the previous hop number (Step S14). The number of hops this time corresponds to the number of hops in the Hello packet received in step S11. The previous hop count is the hop count of the previously received Hello packet stored in the previous storage unit 134.

  The third determination unit 125 determines whether or not the current hop count is less than the previous hop count if the current hop count is less than or equal to the previous hop count (Yes in step S14) (step S15). If the current hop count is less than the previous hop count (Yes at Step S15), the transition section 128 in the control section 120 shifts from the sleep state to the active state (Step S16).

  The control unit 120 stores the issuance time and the number of hops in the Hello packet received in Step S11 and the received electric field strength at the time of receiving the Hello packet in the previous storage unit 134 as previous information (Step S17). Furthermore, the transmission unit 127 in the control unit 120 stores the previous information in the previous storage unit 134, and then transmits a wake-up instruction Hello packet (step S18), and ends the processing operation illustrated in FIG. Each node 100 in the sleep state receives the wake-up instruction Hello packet and transitions the sleep state to the active state when a predetermined condition is satisfied. Each node 100 in the wireless system 10 can communicate with the base node 100 by shifting to the active state, and the main route between the transmitter 11 and the receiver 12 based on the data traffic amount of the own node. Can be rebuilt.

  When the reception unit 121 does not receive the Hello packet for the wake-up instruction (No at Step S11), the reception unit 121 ends the processing operation illustrated in FIG. 16 while continuing the sleep state. If the node 100 is not in the sleep state (No at Step S12), the third determination unit 125 ends the processing operation illustrated in FIG.

  The third determination unit 125 sets the sleep state when the current issue time is not newer than the previous issue time (No at Step S13), or when the current hop number is not less than or equal to the previous hop number (No at Step S14). The processing operation shown in FIG. 16 is finished while continuing.

  If the current hop count is not less than the previous hop count (No at Step S15), the third determination unit 125 determines whether the current received electric field strength is equal to or higher than the previous received electric field strength (Step S19). . Note that the received electric field strength this time corresponds to the received electric field strength in the Hello packet received in step S11. Further, the previous received field strength is the received field strength of the previously received Hello packet stored in the previous storage unit 134. If the current received field strength is greater than or equal to the previous received field strength (Yes at Step S19), the third determination unit 125 proceeds to Step S16 in order to transition to the active state.

  If the current received field strength is not greater than or equal to the previous received field strength (No at Step S19), the third determination unit 125 ends the processing operation illustrated in FIG. 16 while continuing the sleep state.

  When the base node 100 of the main route moves around the node 100 in the sleep state, the base node 100 detects the base point change. When the base point change is detected, the base point node 100 transmits a wake-up instruction Hello packet to the node 100 in the sleep state. When the node 100 in the sleep state receives the Hello packet of the wake-up instruction, the current issue time is newer than the previous issue time, and the current hop count is less than the previous hop count, the sleep state transitions from the sleep state to the active state. To do. As a result, since the wireless system 10 can communicate with the destination node 100 even when the base node 100 moves, the wireless system 10 can reconstruct the main route and the sub route using the destination node 100.

  Further, even when the current hop count is not less than the previous hop count, the destination node 100 shifts from the sleep state to the active state when the current received electric field strength is equal to or higher than the previous received electric field strength. As a result, since the wireless system 10 can communicate with the destination node 100 even when the base node 100 moves, the wireless system 10 can reconstruct the main route and the sub route using the destination node 100.

  FIG. 17 is a flowchart illustrating an example of a processing operation of the control unit 120 in the node 100 related to the sleep transition process. The receiving unit 121 in the control unit 120 of the node 100 illustrated in FIG. 17 determines whether or not a sleep instruction Hello packet has been received (step S21). When the GW 101 receives a Hello packet with a main route setting, the GW 101 requests each node 100 to broadcast a Hello packet with a sleep instruction. The sleep instruction Hello packet stores a sleep instruction, an issue time, and the like.

  When receiving the sleep instruction Hello packet (Yes at Step S21), the second determination unit 123 determines whether or not the own node 100 is a node belonging to the main route or the sub route (Step S22). If the own node is not a node belonging to the main route or the sub route (No at Step S22), the second determination unit 123 determines whether or not the current issue time is newer than the previous issue time (Step S23).

  If the current issue time is newer than the previous issue time (Yes at Step S23), the transition unit 128 transitions from the active state to the sleep state (Step S24). The control unit 120 stores the issuance time and the number of hops in the Hello packet received in step S21 and the received electric field strength at the time of reception in the previous storage unit 134 as previous information (step S25), and ends the processing operation illustrated in FIG. To do.

  When the reception unit 121 does not receive the sleep instruction Hello packet (No at Step S21), the reception unit 121 ends the processing operation illustrated in FIG. 17 while continuing the active state. If the own node 100 is a node belonging to the main route or the sub route (Yes at Step S22), the second determination unit 123 ends the processing operation illustrated in FIG. 17 while continuing the active state. If the current issue time is not newer than the previous issue time (No at Step S23), the second determination unit 123 ends the processing operation illustrated in FIG. 17 while continuing the active state.

  When the node 100 that executes the sleep transition process illustrated in FIG. 17 receives a sleep instruction Hello packet, the node 100 does not belong to the main route or the sub route, and the current issue time is newer than the previous issue time. , Go to sleep. As a result, the wireless system 10 can reduce the power consumption of the node 100 in the sleep state and the traffic amount of the node 100 in the sleep state. For example, when there are 20 nodes 100 belonging to the main route and the sub route among the 100 nodes 100, 80 nodes 100 that do not belong to either the main route or the sub route are shifted to the sleep state. In addition, 80% power consumption and 80% traffic volume can be reduced in the entire wireless system 10. As a result, it is possible to reduce the risk of frame collision and improve throughput.

  Even when the base node 100 of the main route moves, the wireless system 10 reconstructs the main route and the sub route by shifting to the active state in which the node 100 that satisfies the predetermined condition among the nodes 100 in the sleep state can communicate. To do. As a result, even when the base node moves, the wireless system 10 can reconstruct a new main route and sub-route and transfer packets between the transmitter 11 and the receiver 12.

  Furthermore, since the wireless system 10 maintains the sleep state of the node 100 that does not satisfy the predetermined condition among the nodes 100 in the sleep state, the power consumption of the entire wireless system 10 can be reduced and the amount of data traffic can be reduced.

  In the wireless system 10, it is not necessary to determine in advance the timing at which the base point of the main route moves, and it is possible to cope with a case where the base point moves unexpectedly.

  Note that the node 100 in the sleep state according to the above embodiment determines whether or not the node satisfies the predetermined condition when receiving the wake-up instruction Hello packet, and is active from the sleep state when the predetermined condition is satisfied. Moved to the state. However, when a predetermined condition is satisfied, the sleep state may be canceled to enable communication.

  Further, when the node 100 in the sleep state receives the Hello packet for the wake-up instruction and the current hop count is the same as the previous hop count, whether or not the current received electric field strength is equal to or higher than the previous received electric field strength. Determine. Then, the node 100 shifts from the sleep state to the active state when the current received electric field strength is equal to or higher than the previous received electric field strength. However, the node 100 may shift to the active state when the current hop count is the same as the previous hop count.

  In order to prevent communication from being concentrated by transmitting the transmission of the Hello packet among the nodes 100 at the same time, the transmission unit 127 uses a random function and has a wide time for starting the transmission of the Hello packet. I tried to make it. Therefore, the transition unit 128 may cancel the sleep state in accordance with the time width for starting transmission of the Hello packet. As a result, the time for canceling the sleep state can be minimized, and wasteful power consumption in the wireless system 10 can be suppressed.

  The second determination unit 123 of the transfer destination node 100 determines whether or not the own node belongs to the sub-route based on the route state flag and LD information in the Hello packet received from the transfer source node 100. However, the transfer source node 100 can determine whether or not each transfer destination node 100 corresponds to a candidate belonging to the sub-route based on the contents of the flag storage unit 131 and the routing table 132 of the transfer source node 100. . Therefore, the generation unit 126 included in the transfer source node 100 may generate a Hello packet including information indicating that the transfer candidate node 100 corresponds to the candidate. As a result, the second determination unit 123 of the transfer destination node 100 can determine whether or not the own node 100 belongs to the sub-route based on the presence / absence of information indicating that it corresponds to a candidate in the Hello packet.

  The transition unit 128 can also perform mutual transitions to the main route state, the sub-root state, and other states, and the mutual transition to the sleep state and the active state. Only the nodes in other states can transit to the sleep state.

  The transition unit 128 may transition from the main route state to the sub route state. For example, the transition unit 128, for example, when an obstacle is placed on the route to the transfer destination node 100 and the packet is transmitted by bypassing the node 100, the data traffic amount of the main route becomes less than the threshold value. The local node 100 shifts to the sub-root state. In addition, the transition unit 128 may transition from the sub route state to the main route state. For example, it is assumed that the migration unit 128 has a failure in the node 100 belonging to the main route, so that the packet is transferred to the sub-route to which the own node belongs, and the amount of data traffic at the own node exceeds the threshold. When the amount of data traffic of the own node 100 is equal to or greater than the threshold, the transition unit 128 transitions the own node 100 from the sub route state to the main route state.

  The transition unit 128 may transition from the sub route state to the main route state. For example, the transition unit 128 has a higher priority of communication quality with the transmission source node 100 belonging to the main route than the predetermined order because the new node 100 is installed adjacent to the transmission source node 100. In this case, the own node is shifted to the main route state.

  The transition unit 128 can also transition from the sleep state to the active state. For example, the transition unit 128 transitions from the sleep state to the active state when the reception unit 121 receives a wake-up instruction and satisfies a predetermined condition. The transition unit 128 can also transition from the sleep state to the sub-root state. In addition, when the GW 101 has not received a Hello packet with the main route flag ON for a certain period of time, the transition unit 128 temporarily cancels the sleep state. At this time, the second determination unit 123 determines whether or not the own node 100 belongs to the sub-route based on the sub-route flag ON in the Hello packet received from the transfer source node 100. When the transition unit 128 determines that the own node 100 belongs to the sub-root, the transition unit 128 shifts the own node 100 to the sub-root state.

  Further, the processing procedure, control procedure, specific name, and information including various data and parameters shown in the present embodiment can be arbitrarily changed unless otherwise specified.

  Further, each component of the node 100 shown in FIG. 12 is functionally conceptual, and does not necessarily need to be physically configured as illustrated. That is, specific aspects of the reception unit 121, the first determination unit 122, the second determination unit 123, the detection unit 124, the third determination unit 125, the generation unit 126, the transmission unit 127, and the transition unit 128 of the node 100 are as follows. It is not restricted to the thing of illustration. Therefore, all or a part of them can be configured to be functionally or physically distributed / integrated in arbitrary units according to various loads or usage conditions.

  FIG. 18 is an explanatory diagram illustrating an example of a hardware configuration of the node 100. A node 100 illustrated in FIG. 18 includes a CPU 401 that executes various arithmetic processes and a hard disk device 402 that stores various information. Further, the node 100 includes an FPGA 403 that changes a circuit in the node 100 when receiving and transmitting a packet, and a communication module 404 serving as a communication interface when transmitting and receiving the packet.

  The hard disk device 402 corresponds to the storage unit 130 illustrated in FIG. 12, and includes a flag storage unit 131, a routing table 132, a condition table 133, and a previous storage unit 134. Further, the hard disk device 402 includes a reception unit 121, a first determination unit 122, a second determination unit 123, a detection unit 124, a third determination unit 125, a generation unit 126, a transmission unit 127, and a transition unit of the control unit 120. A program having the same function as each of the 128 processing units is stored.

  The CPU 401 reads out each program stored in the hard disk device 402 and executes each program to perform various processes. In addition, these programs include the node 100 as a reception unit 121, a first determination unit 122, a second determination unit 123, a detection unit 124, a third determination unit 125, a generation unit 126, a transmission unit 127, and a transition unit 128. Function as.

  The storage medium readable by the node 100 corresponds to, for example, a portable recording medium such as a CD-ROM, a DVD disk, a USB (Universal Serial Bus) memory, a semiconductor memory such as a flash memory, a hard disk drive, or the like. Further, for example, this program may be stored in a device connected to a public line, the Internet, a LAN (Local Area Network), etc., and the node 100 may read and execute this program.

  FIG. 19 is an explanatory diagram illustrating an example of a hardware configuration of the GW 101. The GW 101 illustrated in FIG. 19 includes a CPU 501 that executes various arithmetic processes, a hard disk device 502 that stores various types of information, an FPGA 503 that changes a circuit inside the GW 101, and a communication module 504 that serves as a communication interface when receiving a packet. Have

  The CPU 501 reads out each program stored in the hard disk device 502 and executes each program to perform various processes. For example, when the CPU 501 first receives a Hello packet in which the main flag is set, the CPU 501 requests each node 100 to perform broadcast transmission of a sleep instruction Hello packet for shifting to a sleep state. The switching hub 505 is a communication interface when transmitting a packet transmitted from the transmitter 11 to the receiver 12 via an ad hoc network.

  The following supplementary notes are further disclosed with respect to the embodiments including the above examples.

(Additional remark 1) The 1st determination part which determines whether the said own apparatus belongs to the radio | wireless apparatus of the communication path | route in the said ad hoc network based on the communication amount which passes through an own apparatus on an ad hoc network,
A transition unit that receives the first signal and determines that the device does not belong to the wireless device of the communication path;
When the second signal is received from the wireless device that has detected the base point change of the communication path, the number of hops of the second signal before the second signal is received in the own device in the power saving state. A second determination unit that determines whether the number of hops of the previous signal received is less than,
A radio apparatus comprising: a cancellation unit that cancels the power saving state of the device when the second determination unit has a hop count of the second signal less than a hop count of the previous signal. .

(Supplementary note 2)
When the second signal has the same number of hops as the previous signal, and when the reception level of the second signal is equal to or higher than the reception level of the previous signal, the power saving state of the own apparatus is canceled. The wireless device according to appendix 1, wherein

(Supplementary Note 3) A wireless system having a plurality of wireless devices on an ad hoc network,
The wireless device includes:
A first determination unit that determines whether or not the own device belongs to a wireless device on a communication path in the ad hoc network, based on a communication amount via the own device on the ad hoc network;
A transition unit that receives the first signal and determines that the device does not belong to the wireless device of the communication path;
When the second signal is received from the wireless device that has detected the base point change of the communication path, the hop number of the second signal is received before the second signal is received in the self-powered device. A second determination unit that determines whether the number of hops of the previous signal is less than,
And a release unit that cancels the power saving state of the device when the second determination unit has a hop count of the second signal less than a hop count of the previous signal. .

(Appendix 4) A wireless method executed by a wireless device,
Based on the amount of traffic that passes through the device on the ad hoc network, determine whether the device belongs to a wireless device on a communication path in the ad hoc network,
When receiving the first signal and determining that the device does not belong to the wireless device of the communication path, the device shifts to the power saving state.
When the second signal is received from the wireless device that has detected the base point change of the communication path, the hop number of the second signal is received before the second signal is received in the self-powered device. Whether the number of hops of the previous signal
The radio | wireless method characterized by performing the process which cancels | releases the said power saving state of the said own apparatus, when the hop number of the said 2nd signal is less than the hop number of the last signal.

(Supplementary note 5)
Based on the amount of traffic that passes through the device on the ad hoc network, determine whether the device belongs to a wireless device on a communication path in the ad hoc network,
When receiving the first signal and determining that the device does not belong to the wireless device of the communication path, the device shifts to the power saving state.
When the second signal is received from the wireless device that has detected the base point change of the communication path, the hop number of the second signal is received before the second signal is received in the self-powered device. Whether the number of hops of the previous signal
A wireless program, wherein when the number of hops of the second signal is less than the number of hops of the previous signal, a process of canceling the power saving state of the device is executed.

DESCRIPTION OF SYMBOLS 10 Wireless system 100 Node 120 Control part 122 1st determination part 124 Detection part 125 3rd determination part 128 Transition part

Claims (4)

A first determination unit that determines whether or not the own device belongs to a wireless device on a communication path in the ad hoc network, based on a communication amount via the own device on an ad hoc network;
A transition unit that receives the first signal and determines that the device does not belong to the wireless device of the communication path;
When the second signal is received from the wireless device that has detected the base point change of the communication path, the number of hops of the second signal before the second signal is received in the own device in the power saving state. A second determination unit that determines whether the number of hops of the previous signal received is less than,
And a release unit that releases the power saving state of the device when the second determination unit has a hop count of the second signal that is less than a hop count of the previous signal. apparatus. The release unit is
When the second signal has the same number of hops as the previous signal, and when the reception level of the second signal is equal to or higher than the reception level of the previous signal, the power saving state of the own apparatus is canceled. The wireless device according to claim 1. A wireless system having a plurality of wireless devices on an ad hoc network,
The wireless device includes:
A first determination unit that determines whether or not the own device belongs to a wireless device on a communication path in the ad hoc network, based on a communication amount via the own device on the ad hoc network;
A transition unit that receives the first signal and determines that the device does not belong to the wireless device of the communication path;
When the second signal is received from the wireless device that has detected the base point change of the communication path, the hop number of the second signal is received before the second signal is received in the self-powered device. A second determination unit that determines whether the number of hops of the previous signal is less than,
And a release unit that cancels the power saving state of the device when the second determination unit has a hop count of the second signal less than a hop count of the previous signal. . A wireless method performed by a wireless device, comprising:
Based on the amount of traffic that passes through the device on the ad hoc network, determine whether the device belongs to a wireless device on a communication path in the ad hoc network,
When receiving the first signal and determining that the device does not belong to the wireless device of the communication path, the device shifts to the power saving state.
When the second signal is received from the wireless device that has detected the base point change of the communication path, the hop number of the second signal is received before the second signal is received in the self-powered device. Whether the number of hops of the previous signal
A wireless method, comprising: executing a process of canceling the power saving state of the own device when the number of hops of the second signal is less than the number of hops of the previous signal.

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