JP5066455B2 - Wireless communication path determination device and wireless communication path determination method - Google Patents

Description

  The present invention relates to a radio communication path determination apparatus and a radio communication path determination method for determining a radio communication path of a radio communication system including a radio communication apparatus having a plurality of radio communication schemes.

  In an ad hoc network having gateways to a plurality of core networks, the following method is known as a route construction method from a wireless communication device to a gateway.

  First, each gateway creates a band information notification message including information related to the band monitored by itself, and transmits the band information notification message to the wireless communication apparatus that starts communication. The band information notification message is delivered from the gateway to the wireless communication device that starts communication by being transferred by another wireless communication device. At this time, the other wireless communication apparatus adds information about the peripheral wireless band monitored by itself to the band information notification message and transfers it. Subsequently, the wireless communication device that has received the bandwidth information notification message constructs a route to the optimal gateway based on the received message (see, for example, Patent Document 1).

  In addition, as a routing protocol used in an ad hoc network, a proactive routing protocol is known in which information is periodically exchanged between wireless communication devices, and a route is constructed based on information exchanged before starting communication. (For example, refer nonpatent literature 1). The proactive routing protocol is characterized in that information on the entire network is shared between wireless communication apparatuses, and a route to an optimal gateway is constructed based on the information.

Japanese Patent Laying-Open No. 2005-079827 IETF RFC3626: Optimized Link State Routing Protocol

  Cognitive radio is configured by a radio communication device using a plurality of radio systems. However, in the conventional route construction method to the gateway, only the information about the distance to the gateway and the band to be used is considered, and the influence of collision and interference between wireless links is not considered. Therefore, the conventional route construction method to the gateway has a problem that it is not possible to suppress deterioration in communication performance due to the influence of collision or interference between wireless links.

  The present invention has been made to solve the above-described problems, and in the case of switching between radio systems using cognitive radio or the like, further suppresses the influence of collision between radio links or interference from other radio links. An object of the present invention is to provide a wireless communication path determination device and a wireless communication path determination method capable of performing the above.

The present invention provides a wireless communication system including a wireless communication device including a plurality of communication units that use different wireless communication methods, wherein the wireless communication device determines a route for performing wireless communication with another wireless communication device. A communication path determination device, information indicating a wireless communication status of each of the wireless communication devices included in the wireless communication system, and whether each wireless communication device is a route capable of communicating using each wireless communication method A storage unit that stores the selected route information, and the route used by each of the wireless communication devices based on the wireless communication status and the selected route information stored in the storage unit and the communication method used in the route preparative a selection unit for sequentially selecting (control unit), and based on the effects of the wireless communication method used by the route which the selecting unit selects a further selectable paths for updating the selected route information Part (control unit), a wireless communication path determining apparatus comprising: a.

According to another aspect of the present invention, there is provided a wireless communication system including a wireless communication device including a plurality of communication units using different wireless communication methods, and a route for the wireless communication device to perform wireless communication with the other wireless communication device is determined. A wireless communication path determination method for determining whether or not each wireless communication apparatus included in the wireless communication system is a path through which each wireless communication apparatus can communicate using each wireless communication method. A storage step that stores selected route information that is information to be shown; and the route used by each of the wireless communication devices and the route used based on the wireless communication status and the selected route information stored in the storage step a selection step of sequentially selecting a communication scheme based on the effects of the wireless communication method used by the route selected in said selection step, further the selected route information A selectable path updating step of a wireless communication path determination method, which comprises a.

  ADVANTAGE OF THE INVENTION According to this invention, when switching and using a radio system by cognitive radio etc., the influence of collision and interference of radio links can be suppressed more.

  Hereinafter, an embodiment of the present invention will be described. In the present embodiment, a mesh network (wireless communication system) configured by wireless communication devices that support two or more types of wireless communication methods, and a wireless communication system in which two or more gateways exist are targeted. To do.

  FIG. 1 is a diagram showing a configuration of a wireless communication apparatus (node) according to an embodiment of the present invention. The wireless communication device includes a control unit 11, a storage unit 12, a communication unit A13, a communication unit B14, and a communication unit C15. The control unit 11 controls the wireless communication device. The storage unit 12 stores information used by the wireless communication device. The communication unit A13 communicates with other wireless communication devices using the wireless method A. The communication unit B14 communicates with other wireless communication devices using the wireless method B. The communication unit C15 communicates with other wireless communication devices using the wireless method C.

  As a specific example of the wireless system, the wireless system A may be IEEE802.11a, the wireless system B may be IEEE802.11b, and the wireless system C may be IEEE802.16. Also, these may be wireless systems A, B, and C, respectively, as long as the channels are different in IEEE 802.11b.

  FIG. 2 is a diagram illustrating a configuration example of a wireless communication system according to the present embodiment. In the illustrated example, the wireless communication system includes ten wireless communication devices A to J. The wireless communication device A is connected to the wireless communication device B and the wireless communication device E. The wireless communication device B is connected to the wireless communication device A, the wireless communication device C, and the wireless communication device F. The connection states of other wireless communication devices are as shown in the figure. The wireless communication device E and the wireless communication device I are connected to the gateway a. The wireless communication device J and the wireless communication device H are connected to the gateway b. Gateways a and b are connected to the core network. Each wireless communication device can be connected to the core network via gateway a or gateway b. For example, there are a plurality of paths through which the wireless communication apparatus F is connected to the core network. As an example, the wireless communication apparatus F can be connected to the core network via the wireless communication apparatus E and the gateway a.

  In the present embodiment, each wireless communication device included in the wireless communication system periodically transmits and receives beacons with other wireless communication devices, so that information on other wireless communication devices connected to the own wireless communication device is obtained. In addition, the information of the other wireless communication device including the information on the wireless method is transmitted to the other wireless communication device. Thereby, each wireless communication device grasps information of the wireless communication device included in the network. In addition, the information of the wireless communication device connected to the gateway is also grasped in the same manner. Based on this grasped information, each wireless communication device calculates a route from its own wireless communication device to the gateway and selects a better route. Note that the wireless communication device that calculates the route from the own wireless communication device to the gateway may be one specific wireless communication device, or may be only a part of a plurality of wireless communication devices, or may be all wireless communication devices. In addition, regarding the calculation order, the wireless communication devices to be calculated are selected in an arbitrary order, and the calculation is performed for each wireless communication device.

  In the route calculation of the present embodiment, in consideration of the prediction of the occurrence of interference and collision of the wireless communication method used between the wireless communication apparatuses, wireless communication in which the influence value of the prediction of the occurrence of interference and collision exceeds a predetermined threshold value The route including the method is not selected, and another route is selected for calculation. As for the influence of interference and collision, the influence value is calculated assuming that interference and collision occur by neighboring wireless links.

  In the route calculation of the present embodiment, the route from the wireless communication device to a plurality of gateways included in the wireless communication system is calculated, and the route with the best evaluation value calculated from the interference and collision influence values is automatically determined. A connection path from the wireless communication device to the gateway is used. When calculating the route from another wireless communication device to the gateway, the influence of interference and collision due to the route of another wireless communication device that has already been determined is reflected as an influence value in the calculation. As a result, the influence of interference and collision with the already determined route can be reduced.

  It is also conceivable that the route to the gateway cannot be determined based on the influence value of interference and collision from the route used by another wireless communication device. In this case, if a route to any gateway is determined, the route is determined as a route to the gateway. If no route to the gateway can be determined, the predetermined calculation condition is changed and the calculation is performed again. In the present embodiment, the route from the wireless communication device to the gateway is calculated as described above, and the route with the best condition is determined as the route from the wireless communication device to the gateway.

  Next, a method for determining a route from the wireless communication apparatus to the gateway according to the present embodiment will be described with reference to FIGS.

  First, the control unit 11 of each wireless communication device (node) creates a beacon. The communication unit A13, the communication unit B14, and the communication unit C15 each transmit a beacon created by the control unit 11 to adjacent (connected) wireless communication devices.

  Information included in the beacon will be described with reference to FIG. FIG. 3 is a diagram illustrating an example of a format of information included in a beacon transmitted by the wireless communication apparatus according to the present embodiment. In the illustrated example, the beacon includes four attributes: a destination address, a transmission wireless communication device ID, a transmission wireless method ID, and an adjacent wireless communication device ID. The destination address indicates a destination address (broadcast address) of the beacon. The outgoing wireless communication device ID indicates the ID of the wireless communication device that is the transmission source of the beacon. The transmission wireless system ID indicates an ID of a wireless communication system that transmits a beacon. For example, suppose that A is a transmission wireless method ID of a beacon transmitted using the wireless method A. The adjacent wireless communication device ID indicates the ID of the wireless communication device adjacent to the wireless communication device indicated by the originating wireless communication device ID. For example, when the transmission wireless communication device ID is α, the transmission wireless method ID is A, and the adjacent wireless communication device IDs are β and γ, the wireless method A is used and the wireless communication device ID is β. The communication device and the wireless communication device of γ indicate that the wireless communication device ID is adjacent to the wireless communication device of α.

  Subsequently, the communication unit A13, the communication unit B14, and the communication unit C15 of each wireless communication device receive a beacon transmitted from an adjacent wireless communication device. The control unit 11 registers information in the adjacent wireless communication device table based on the beacons received by the communication unit A13, the communication unit B14, and the communication unit C15. In addition, when the information included in the already received beacon is registered in the adjacent wireless communication device table, the registered information is updated.

  Information included in the adjacent wireless communication device table will be described with reference to FIG. FIG. 4 is a diagram showing an example of the format of the adjacent wireless communication device table in the present embodiment. In the illustrated example, the adjacent wireless communication device table includes three attributes of an adjacent wireless communication device ID, a wireless method ID, and an adjacent state. The adjacent wireless communication device ID and the wireless method ID store a transmission wireless communication device ID and a transmission wireless method ID included in the received beacon, respectively. As the adjacent state, a value of “one direction” or “both directions” is stored. The connection state “one-way” indicates that a beacon is received from the target wireless communication device, and the connection state “two-way” is a beacon received from the target wireless communication device and transmitted to the target wireless communication device. It shows that. Therefore, when information is newly stored in the adjacent wireless communication device table, the adjacent state is “one-way”, and when information is already stored, the adjacent state is “two-way”.

  In the illustrated example, the adjacent wireless communication device ID is “α”, the wireless method ID is “A”, the adjacent state is “one-way”, and the adjacent wireless communication device ID is “α”. , The wireless system ID is “B”, the adjacent state is “bidirectional”, the adjacent wireless communication device ID is “β”, the wireless system ID is “A”, and the adjacent state is “ Lines that are “both directions”. Therefore, the wireless communication device storing the adjacent wireless communication device table receives a beacon transmitted by the wireless method A from the wireless communication device with the wireless communication device ID α, and the wireless communication device ID is α. A beacon transmitted from the wireless communication device by the wireless method B is received, a beacon is transmitted by the wireless method B to the wireless communication device having the wireless communication device ID α, and the wireless communication device ID is β A beacon transmitted from the communication device by the wireless method A is received, and the beacon is transmitted by the wireless method A to the wireless communication device whose wireless communication device ID is β.

  Subsequently, the control unit 11 of each wireless communication device performs wireless communication using information on the wireless communication device in which the adjacent state is “bidirectional” in the adjacent wireless communication device table stored in the storage unit 12 as a topology information packet. Flood the system. Thereby, the topology information stored in each wireless communication device can be shared by the entire wireless communication system. In addition, the control unit 11 stores information included in the received topology information packet in the topology information table stored in the storage unit 12. Further, the control unit 11 floods the wireless communication system by including the information of the topology information table in the topology information packet. When the own wireless communication device is connected to the core network, the other wireless communication device is notified that it is connected to the core network. As a notification method, it may be transmitted by being included in a topology information packet, or may be transmitted individually as a gateway information packet.

  The topology information packet will be described with reference to FIG. FIG. 5 is a diagram showing an example of a format of information included in the topology information packet transmitted by the wireless communication apparatus in the present embodiment. In the illustrated example, the topology information packet includes six attributes: a destination address, a transmission wireless communication device ID, a core network connection flag, a core network address, an adjacent wireless communication device ID, and a wireless method ID. The destination address indicates a destination address (broadcast address) of the topology information packet. The originating wireless communication device ID indicates the ID of the wireless communication device that is the transmission source of the topology information packet. The core network connection flag indicates whether or not the wireless communication device having the transmission wireless communication device ID is connected to the core network. For example, if the core network connection flag is “0”, it indicates that the core network is not connected, and if it is “1”, it indicates that the core network is connected. The core network address indicates the address of the connected core network. The adjacent wireless communication device ID indicates an ID of a wireless communication device adjacent to the wireless communication device of the transmission wireless communication device ID. The wireless method ID indicates the ID of the wireless method used when connecting to the wireless communication device having the outgoing wireless communication device ID.

  The topology information table will be described with reference to FIG. FIG. 6 is a diagram showing an example of the format of the topology information table stored in the storage unit 12 of the wireless communication apparatus in the present embodiment. In the illustrated example, the topology information table includes three attributes: an advertisement wireless communication device ID, an adjacent wireless communication device ID, and a wireless method ID. The advertisement wireless communication device ID indicates a transmission wireless communication device ID included in the topology information packet. The adjacent wireless communication device ID indicates an adjacent wireless communication device ID included in the topology information packet. The wireless method ID indicates a wireless method ID included in the topology information packet.

  In the illustrated example, the advertising wireless communication device ID is α, the adjacent wireless communication device ID is β, the wireless method ID is A, the advertising wireless communication device ID is α, and the adjacent wireless communication device ID. Includes a row in which the wireless method ID is B and a row in which the advertising wireless communication device ID is β, the adjacent wireless communication device ID is γ, and the wireless method ID is A. In this example, the wireless communication device α and the wireless communication device β are connected by the wireless method A, the wireless communication device α and the wireless communication device β are connected by the wireless method B, and the wireless communication device β and the wireless communication device β are wirelessly connected. The communication device γ is connected by the wireless system A.

  As described above, each wireless communication device can acquire information on other wireless communication devices and information on wireless communication devices connected to the core network from the flooding packet.

  Subsequently, the control unit 11 of each wireless communication device calculates a route from the wireless communication device to the gateway based on the acquired information. The route calculation procedure will be described with reference to FIG. FIG. 7 is a flowchart showing a procedure for calculating a route from the wireless communication apparatus to the gateway in the present embodiment. In the present embodiment, the control unit 11 of a certain wireless communication device included in the wireless communication system calculates a route from the wireless communication device to the gateway. Note that the route from the wireless communication device to the gateway is not limited to the wireless communication device. For example, the gateway calculates the route from the wireless communication device to the gateway, and the result calculated by each wireless communication device. You may tell.

  (Step S101) The control unit 11 determines whether there is an uncalculated wireless communication device among the wireless communication devices to be calculated. If it is determined that there is an uncalculated wireless communication device, the process proceeds to step S102, and otherwise the process ends. The wireless communication device to be calculated is designated in advance. The designated wireless communication device may be only one wireless communication device, a part of a plurality of wireless communication devices, or all wireless communication devices included in the wireless communication system. For example, it is conceivable that only a plurality of wireless communication devices that actually have communication requests are designated as calculation target wireless communication devices, or only a wireless communication device that is to be preferentially handled is designated.

  (Step S <b> 102) The control unit 11 selects one wireless communication device in an arbitrary order from the wireless communication devices to be calculated specified in advance. Thereafter, the process proceeds to step S103. As an example of the order of selection, there may be a case where selection is made in the order of wireless communication device IDs, a case where selection is made in the order of wireless communication devices to be prioritized, or a case where selection is made in order of wireless communication devices which are close to or far from the gateway. . Note that. When selecting based on the distance to the gateway, the selection is made based on the value obtained by the shortest hop route calculation described later.

  (Step S103) The control unit 11 sets a threshold value. Thereafter, the process proceeds to step S104. The threshold value is used when calculating the influence value of interference and collision of a radio link, which will be described later, and determining that a radio link exceeding a preset threshold value cannot be selected. In principle, a preset value is used as the threshold value.

  (Step S104) The control unit 11 calculates a route from the wireless communication device to be calculated selected in Step S102 to the gateway. Thereafter, the process proceeds to step S105. In wireless communication, when communication is performed using a certain wireless link, interference and collision with wireless link communication performed by other wireless communication devices in the vicinity may occur due to wireless broadcast characteristics. Therefore, in step S104, the influence value of the interference and the collision of the wireless link is calculated, and the route is calculated after making it impossible to select the wireless link exceeding the preset threshold. A specific route calculation method will be described later. In addition, since the link cannot be used due to the influence of interference and collision, it may be impossible to establish any path from the wireless communication apparatus to be calculated to the gateway.

  (Step S105) The control unit 11 determines whether or not a route from the wireless communication device to be calculated to one or more gateways has been established in step S104. If it is determined that it has been established, the process proceeds to step S107. Otherwise, the process proceeds to step S106.

  (Step S106) The control unit 11 recalculates the threshold value determined in Step S103, lowers the criterion (threshold value) for disabling use due to interference and collision, and newly establishes a new route in Step S104. Set an appropriate threshold. Thereafter, the process returns to step S104.

  (Step S107) The control unit 11 selects the route having the best condition from the routes determined in Step S104, and determines the selected route as the route from the wireless communication apparatus selected in Step S102 to the gateway. Then, it progresses to step S101.

  By the procedure described above, it is possible to further suppress the influence of collision and interference between wireless links, and to determine the route from each wireless communication device to the gateway.

  Next, a determination policy (policy) for a wireless link that cannot be used when determining a route in step S104 will be described. In the present embodiment, in order to avoid radio interference / collision between multi-hop links through which the route with the gateway itself passes and between multiple routes, the adjacency relationship in the following network topology and the CSMA / CA (C.S. Policy (policy) in consideration of operation of M / C, Carrier Sense Multiple Access / Collision Avid and RTS / CTS (Request to Send / Clear to Send) Select the wireless method according to.

  Specifically, the other wireless communications that are affected by the wireless system used in the link between the wireless communication device S (transmitting-side wireless communication device) and the wireless communication device D (receiving-side wireless communication device) are the following (1) From (8) to (8), the wireless method is selected according to the following policy (policy) considering the effects of (1) to (8).

(1) A wireless link between the wireless communication device S and the wireless communication device D to be calculated.
(2) A transmission link transmitted from the wireless communication device S. In this link, no interference / collision occurs, and only the influence of scheduling occurs.
(3) A reception link received by the wireless communication device S.
(4) A transmission link transmitted from the wireless communication device D.
(5) A reception link received by the wireless communication device D.
(6) A transmission link transmitted by a wireless communication device that is topologically adjacent to the wireless communication device S (wireless communication device group 1 in FIG. 9 described later). When these wireless communication devices use the same wireless method as that used for the link between the wireless communication device S and the wireless communication device D, the data transmitted by the wireless communication device S may collide and interfere. is expected.
(7) A reception link received by a wireless communication device that is topologically adjacent to the wireless communication device S (wireless communication device group 1 in FIG. 9 described later). When these wireless communication devices use the same wireless method as that used in the link between the wireless communication device S and the wireless communication device D, the influence of collision / interference on the reception of data received by the wireless communication device S Is expected to give
(8) A transmission link transmitted by a wireless communication device that is topologically adjacent to the wireless communication device D (wireless communication device group 2 in FIG. 9 described later). When these wireless communication devices use the same wireless method as that used in the link between the wireless communication device S and the wireless communication device D, the wireless communication device D receives a collision and interferes with the reception of data received. It is expected that.

  A wireless communication device that is topologically adjacent to the wireless communication device D but is not topologically adjacent to the wireless communication device S is a hidden terminal when viewed from the wireless communication device S. In addition, in the RTS / CTS operation, a wireless communication apparatus that does not make a call by receiving CTS is obtained. The reception links received by wireless communication devices that are topologically adjacent to the wireless communication device D but not topologically adjacent to the wireless communication device S correspond to (1) to (8). Unless this is done, the wireless method used in the link between the wireless communication device S and the wireless communication device D is not affected.

  In addition, in accordance with the policy (policy) in consideration of the effects (1) to (8) above, the following steps S201 to S206 are examined, and an unusable wireless method is selected. As a result, it is possible to determine a wireless link that cannot be used for route calculation in step S104.

(Step S201) For each wireless method, a threshold value used to determine the availability of the wireless link due to the influence of interference / collision is defined.
(Step S202) For each policy, a coefficient indicating the influence of interference / collision is defined.
(Step S203) The calculation of the influence value for each flow can be selected from the calculation using the requested bandwidth of the flow or the calculation using a constant. When the calculation is performed using the requested bandwidth of the flow, the influence value of each policy is calculated by (required bandwidth) × (coefficient of the policy). On the other hand, when calculation is performed using a constant, the influence value of each policy is calculated by (constant) × (coefficient of the policy).
(Step S204) When the use of a certain radio link is determined, the influence value due to the use is calculated for all the above policies. At this time, when a plurality of policies are applicable, the one having the highest influence value is applied.
(Step S205) The value of the influence value in each radio link is integrated.
(Step S206) Whether or not the wireless link can be used is determined based on whether or not the integrated influence value exceeds a threshold value.

  Hereinafter, an example of selecting a wireless method that cannot be used in accordance with steps S201 to S206 in consideration of (1) to (8) will be described with reference to FIGS. 8 to 10 are diagrams showing examples of a part of the wireless communication system according to the present embodiment.

  In the example illustrated in FIGS. 8 to 10, wireless communication devices 801 to 809 are included in a part of the wireless communication system. The wireless communication devices 801 to 809 include communication units A13 to C15, respectively. The wireless communication device 801 is connected to the wireless communication device 802 and the wireless communication device 804. The connection of other wireless communication devices is as illustrated. In addition, wireless communication devices that can receive radio waves transmitted by the wireless communication device 801 are a wireless communication device 804 and a wireless communication device 802 that are closer to the wireless communication device 801 than a broken line 810. The wireless communication device 804 that is topologically adjacent to the wireless communication device 801 is defined as the wireless communication device group 1, and the wireless communication device 803 and the wireless communication device 805 that are topologically adjacent to the wireless communication device 802 are wirelessly connected. The communication device group 2 is assumed.

  FIG. 8 is a diagram when a wireless link from the wireless communication apparatus 801 to the wireless communication apparatus 802 is selected in the present embodiment. In the illustrated example, a wireless link is established from the wireless communication device 801 to the wireless communication device 802 using the communication unit A13.

  FIG. 9 shows a wireless link that cannot be used by the wireless communication devices 801 to 809 when a wireless link is established from the wireless communication device 801 to the wireless communication device 802 using the communication unit A13 in this embodiment. FIG. The wireless link that cannot be used uses the communication unit A13 from the wireless communication device 801 to the wireless communication device 802 as a result of examining steps S201 to S206 according to the policies (1) to (8) described above. Wireless link determined to be affected by the established wireless link.

  In the illustrated example, an unusable wireless link is indicated by an arrow 90. For example, a wireless link that transmits data from the wireless communication device 801 to the wireless communication device 804 using the communication unit A13 cannot be used. It is said. In addition, a wireless link that transmits data from the wireless communication device 804 to the wireless communication device 801 using the communication unit A13 is disabled. Other wireless links that cannot be used are as illustrated.

  FIG. 10 illustrates a wireless communication apparatus in which wireless communication apparatuses 801 to 809 cannot use each other when a wireless link is established from the wireless communication apparatus 801 to the wireless communication apparatus 802 using the communication unit A13 in the present embodiment. It is the figure which deleted the link. In the illustrated example, the wireless link of the communication unit A13 is deleted between the wireless communication device 801 and the wireless communication device 804. Other deleted radio links are as illustrated.

  Of the links between the wireless communication devices, a link that cannot be used only from one of the wireless communication devices is indicated by an arrow 90 as in FIG. For example, in a wireless link using the communication unit A13 between the wireless communication device 803 and the wireless communication device 806, data is transmitted from the wireless communication device 803 to the wireless communication device 806 using the communication unit A13. The wireless link cannot be used, but the wireless link that transmits data from the wireless communication device 806 to the wireless communication device 803 using the communication unit A13 can be used. Other wireless communication devices are as illustrated.

  Next, a policy (policy) for calculating a route in step S104 will be described. In the present embodiment, policies for calculating a route are the following (11) to (13).

(11) Basically, the shortest cost route based on the cost assigned to the link is selected. Examples of the cost include values calculated from the number of hops, transmission bandwidth, delay, and the like.
(12) Do not use a radio link whose selection is prohibited by a radio policy considering the occurrence of collision / interference.
(13) If it is possible to ride in the same direction on a radio link assigned to another route that has already been determined, the assignment is taken on an initiative.

Next, an outline of the algorithm used in step S104 for determining a route based on the above-described policy will be described.
(Step S1041) Considering the influence of the already determined route, the state of the wireless link such as the cost of each wireless link and the determination of a link that cannot be used due to interference / collision is calculated.
(Step S1042) The route from the wireless communication device selected in step S102 to the gateway is calculated by the Dijkstra method with cost. Unlike the conventional Dijkstra method, the costed Dijkstra method used in this embodiment calculates a radio link that cannot be selected by assignment every time one link is assigned, and uses that radio method for subsequent hops. If the route cannot be calculated due to insufficient bandwidth or interference / collision, the process proceeds to calculation of a route to another gateway.

  Hereinafter, an algorithm of the Dijkstra method with cost in the present embodiment will be described. The variables used in the description are as follows.

p (x): Indicates the wireless communication device of the previous hop of the wireless communication device x. Since the wireless communication device s is the starting point, the previous hop is φ (empty set). Further, in the present embodiment, recording is performed in association with the wireless system that passes through.
dist (x): Indicates a fixed distance from the wireless communication device s that is the starting point to the wireless communication device x.
V: A set of wireless communication devices.
s: Indicates the wireless communication device at the starting point.
U: Indicates a set of wireless communication devices for which the shortest distance has not yet been determined.
dist_temp (x): indicates a provisional distance from the wireless communication device at the starting point to the wireless communication device x.
N (x): A set of wireless communication devices adjacent to the wireless communication device x.
cost (x, y): indicates the cost of the link between the wireless communication device x and the wireless communication device y. When there are a plurality of wireless method links between the wireless communication device x and the wireless communication device y, the link with the lowest cost is selected from the selectable wireless methods.
T: A set of links (taboo list) that cannot be selected by a route that has already been assigned.

(Step S301) The controller 11 initializes parameters used in the Dijkstra method. Specifically, the following steps S3011 to S3013 are performed. The parameters are stored in the storage unit 12.
(Step S3011) p (s) is φ, dist (s) is 0, and U is “V− {s}”.
(Step S3012) For all wireless communication devices v (where vεU), dist_temp (v) is set to ∞ (infinite) (Step S3013) A link that cannot be selected by the already assigned route is displayed in the tabu list T. Manage as (already assigned).

  (Step S302) The control unit 11 calculates the cost from the wireless communication device s to the adjacent wireless communication device v. It is assumed that dist_temp (v) of all wireless communication devices v (vεN (s)) is cost (s, v) and p (v) is s.

  (Step S303) The control unit 11 determines a route from the starting wireless communication device s to the destination wireless communication device d (wireless communication device d connected to the gateway). The determination of the route is performed by repeatedly performing the following steps S3031 to S3034. When the route is confirmed, the confirmed route is treated as an already assigned route.

(Step S3031) The wireless communication device w having the smallest dist_temp (w) is selected from the set U. Thereafter, the process proceeds to step S3032.
(Step S3032) dist (w) is set to dist_temp (w), and U is set to “U− {w}”. Thereafter, the process proceeds to step S3033.
(Step S3033) Based on the link between w and p (w), a wireless link that can no longer be selected is determined, and the determined link is held as a tabu list T (w). Thereafter, the process proceeds to step S3034.
(Step S3034) The following processing is executed for all wireless communication devices v (vεN (w) ∩U). If “dist (w) + cost (w, v)” is smaller than dist_temp (v) and the link between the wireless communication device w and the wireless communication device v is not included in the tabu list (ie, select) If possible, dist_temp (v) is set to dist (w) + cost (w, v), and p (v) is set to w. Note that the tabu list considered in step S3034 includes T (already allocated), and x = {w, p (w), p (p (w)... S)} and determined wireless communication from w to s. It becomes T (x) in the wireless communication apparatus that has traced the apparatus.

  As described above, the route from the wireless communication device selected in step S102 to the gateway and the evaluation value of each route can be calculated by the Dijkstra method with cost by the processing of step S301 to step S303. In addition, as an evaluation value, the value of the cost calculated | required by route calculation, the number of hops, etc. are mentioned.

  Further, when the determined wireless communication device is the destination wireless communication device (wireless communication device connected to the gateway), the route is fixed, and the route from the wireless communication device selected in step S102 to the gateway is p (d), This is the reverse order of the path followed by p (p (d)),. If the destination cannot be reached due to restrictions on wireless use, the calculation ends at that point.

  Further, the evaluation value may be a value calculated by multiplying each of the coefficients based on the sum of the cost of the route and the sum of the influence values of the interference / collision of the wireless link through which the route passes. Specifically, a value obtained by (coefficient 1) × (sum of cost of route) + (coefficient 2) × (sum of influence values of interference / collision of radio link through which route passes) may be used as the evaluation value. . In this case, a route with a small value is a route with good conditions.

  As described above, when no route from the wireless communication apparatus to the gateway can be determined, the threshold is increased and the calculation is performed again.

  Also, when the wireless communication device that was the object of calculation stops communication, the route between the wireless communication device and the gateway is canceled. As a result, since the influence of radio interference / collision changes, recalculation may be performed. In this case, recalculation may be performed for all wireless communication devices, or only some wireless communication devices may be calculated.

  Hereinafter, a specific calculation example using the costed Dijkstra algorithm according to the present embodiment will be described with reference to the processing in steps S301 to S303.

  FIG. 11 is a diagram illustrating a configuration example of a wireless communication system in the present embodiment. In the illustrated example, the wireless communication system includes 16 wireless communication devices N1 to N16. The wireless communication device N1 is connected to the wireless communication device N2 and the wireless communication device N5. The wireless communication device N2 is connected to the wireless communication device N1, the wireless communication device N3, and the wireless communication device N6. The connection states of other wireless communication devices are as shown in the figure. The wireless communication device N10 and the wireless communication device N16 are connected to a gateway (not shown). The wireless communication devices N1 to N16 include communication units A13 to C15, respectively.

  With reference to FIG. 11, a method for calculating a route from the wireless communication device N1 and the wireless communication device N3 to the gateway will be described as an example. In this calculation example, when there are a plurality of calculation candidate wireless communication apparatuses, the calculation is performed in order from the smallest wireless communication apparatus number. In this embodiment, the wireless communication apparatus number is a number after N. Specifically, the wireless communication device number of the wireless communication device N1 is 1, and the wireless communication device number of the wireless communication device N3 is 3. Therefore, as a calculation order, after calculating the route from the wireless communication device N1 to the gateway, the route from the wireless communication device N3 to the gateway is calculated.

  Note that when considering only the hop count without considering radio interference, the hop count from the radio communication device N1 to the radio communication device N10 connected to the gateway is three hops, and the radio communication device N3 to the gateway. The number of hops to the connected wireless communication device N10 is also 3 hops. The number of hops from the wireless communication device N1 to the wireless communication device N16 connected to the gateway is 6 hops, and the number of hops from the wireless communication device N3 to the wireless communication device N16 connected to the gateway is 4 hops.

<Calculation of route from wireless communication device N1 to each gateway>
In accordance with the calculation order described above, the route from the wireless communication device N1 to the wireless communication device N10 and the wireless communication device N16 connected to the gateway is calculated.

  First, variables are initialized as a calculation preparation. Specifically, the wireless communication device set V is set as {N1, N2, N3, N4, N5, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16}. The starting point wireless communication device S is set to N1.

  The adjacent wireless communication device N (N1) of the wireless communication device N1 is set as {N2, N5}. The adjacent wireless communication device N (N2) of the wireless communication device N2 is set as {N1, N3, N6}. The adjacent wireless communication device N (N3) of the wireless communication device N3 is set as {N2, N4, N7}. The adjacent wireless communication device N (N4) of the wireless communication device N4 is set as {N3, N8}. The adjacent wireless communication device N (N5) of the wireless communication device N5 is set as {N1, N6, N9}. The adjacent wireless communication device N (N6) of the wireless communication device N6 is set as {N2, N5, N7, N10}. The adjacent wireless communication device N (N7) of the wireless communication device N7 is set as {N3, N5, N8, N11}. The adjacent wireless communication device N (N8) of the wireless communication device N8 is set as {N4, N7, N12}.

  The adjacent wireless communication device N (N9) of the wireless communication device N9 is set as {N5, N10, N13}. The adjacent wireless communication device N (N10) of the wireless communication device N10 is set as {N6, N9, N11, N14}. The adjacent wireless communication device N (N11) of the wireless communication device N11 is set as {N7, N10, N12, N15}. The adjacent wireless communication device N (N12) of the wireless communication device N12 is set as {N8, N11, N16}. The adjacent wireless communication device N (N13) of the wireless communication device N13 is set as {N9, N14}. The adjacent wireless communication device N (N14) of the wireless communication device N14 is set as {N10, N13, N15}. The adjacent wireless communication device N (N15) of the wireless communication device N15 is set as {N11, N14, N16}. The adjacent wireless communication device N (N16) of the wireless communication device N16 is set as {N12, N15}.

  The cost of the link between the wireless communication device x and the wireless communication device y is set for each communication unit. The cost is different for each wireless system. When the cost of the wireless system A is 1, the cost of the wireless system B is 2, and the cost of the wireless system C is 3, the cost cost (x, y) when using the communication unit A13 is calculated. 1 is set, the cost cost (x, y) when using the communication unit B14 is set to 2, and the cost cost (x, y) when using the communication unit C15 is set to 3.

  The threshold used for determining the influence value of interference / collision is set to 1. In addition, when the above policy (1) to (8) is considered, a constant 1 is set. As a result, among the policies that take into account (1) to (8), a policy that restricts the use of the radio scheme is applicable to one radio scheme that applies.

Then, the process of step S301-step S303 is implemented.
(Step S301) Steps S3011 to S3013, which are processes for initializing parameters used in the Dijkstra method, are performed.
(Step S3011) Let p (N1) be φ (empty set). Also, dist (N1) is set to 0. Moreover, let U be V- {N1}. That is, U is set to {N2, N3, N4, N5, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16}.
(Step S3012) For all wireless communication devices v (where vεU), dist_temp (v) is set to ∞ (infinity).
(Step S3013) A link that cannot be selected by a route that has already been assigned is managed as a tabu list T (already assigned). Since there is no assigned route at this time, there is no particular change.

  (Step S302) The cost from the starting wireless communication device s (wireless communication device N1) to the adjacent wireless communication device v is calculated. It is assumed that dist_temp (v) of a wireless communication device v (vεN (N1) = {N2, N5}) adjacent to the wireless communication device N1 is cost (s, v) and p (v) is s. That is, dist_temp (N2) of N2, N5εN (N1) is set to cost (N1, N2) = 1. This is for selecting the communication unit A13 having the lowest cost among the selectable communication units A13 to C15. Also, dist_temp (N5) is set to cost (N1, N5) = 1. This is for selecting A which is the lowest cost among the selectable communication units A13 to C15. Further, p (N2) is N1 (via communication method A), and p (N5) is N1 (via communication method A).

  (Step S303 (first time)) A route from the start wireless communication device s to the destination wireless communication device d is determined. In order to determine the route, the processes in steps S3031 to S3034 are repeated until the wireless communication device N10 and the wireless communication device N16 that are the destination wireless communication devices d are reached.

  (Step S3031) Radio in which dist_temp (w) is the minimum among the set U = {N2, N3, N4, N5, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16} A communication device w is selected. At present, dist_temp (N2) and dist_temp (N5) are 1, and other dist_temp (v) is ∞ (infinite), so that wireless communication with the wireless communication device N2 that is the wireless communication device candidate with the lowest cost is performed. The wireless communication device N2 having a smaller wireless communication device number is selected as the wireless communication device w from the device N5.

  (Step S3032) dist (w = N2) is set to dist_temp (N2) = 1. Also, U is U as V- {N1}. That is, U is set to {w = N2} = {N3, N4, N5, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16}.

  (Step S3033) Based on the link between N2 and p (N2), a wireless link that cannot be selected is determined thereafter, and the determined wireless link is held as a tabu list T (N2). Since p (N2) is N1 (via communication method A), T (N2) is changed to {via communication method A (N1⇔N2, N1⇔N5, N2⇔N3, N2⇔N6, N5⇔N6, N5⇔N9). , N3⇔N4, N3⇔N7, N6⇔N7, N6⇔N10)}.

  For example, the meaning of the tabu list {via communication method A (N1⇔N2, N2⇔N3)} means the link between the wireless communication device N1 and the wireless communication device N2 using the communication method A, and the wireless communication device. This means that the link between N2 and the wireless communication device N3 cannot be used.

  (Step S3034) The following processing is executed for all wireless communication devices v (v is vεN (w = N2) ∩U = {N1, N3, N6} ∩U = {N3, N6}). “Dist (w) + cost (w, v)” is smaller than dist_temp (v), and the link between the wireless communication device w and the wireless communication device v must be included in the target tabu list T (N2). For example, dist_temp (v) is set to dist (w) + cost (w, v), and p (v) is set to w.

  The process of step S3034 will be specifically described. First, processing is executed for a case where the wireless communication apparatus number is small and v is N3. cost (N2, N3) varies depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A is included in the taboo list, it cannot be selected. The next lowest cost communication method B is not included in the tabu list, and dist (N2) + cost (N2, N3) = 3, which is smaller than dist_temp (N3) = ∞, so the condition is satisfied. Therefore, dist_temp (N3) is set to 3, and p (N3) = N2 (via communication method B).

  Subsequently, the process is executed also when v is N6. The cost (N2, N6) differs depending on the communication method, and is 1 through the communication method A, 2 through the communication method B, and 3 through the communication method C. Here, since the communication method A is included in the taboo list, it cannot be selected. The communication method B via the next lowest cost is not included in the tabu list, and dist (N2) + cost (N2, N6) = 3, which is smaller than dist_temp (N6) = ∞, which satisfies the condition. Therefore, dist_temp (N6) is set to 3, and p (N6) = N2 (via communication method B). Since the process is executed for all the calculation target wireless communication devices v (vεN (N2) ∩U), the next route (wireless communication device) is searched.

  (Step S303 (second time)) In order to determine the route, the processes of Steps S3031 to S3034 are repeated until the wireless communication device N10 and the wireless communication device N16 that are the destination wireless communication devices d are reached.

  (Step S3031) Wireless communication apparatus in which dist_temp (w) is minimized from among set U = {N3, N4, N5, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16} Select w. At present, dist_temp (N5) is 1, dist_temp (N3) and dist_temp (N6) are 3, and other dist_temp (v) is ∞ (infinite), so the wireless communication apparatus with the minimum cost N5 is selected as the wireless communication device w.

  (Step S3032) dist (w = N5) is set to dist_temp (N5) = 1. Also, let U be V- {w = N5}. That is, U is set to {N3, N4, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16}.

  (Step S3033) Based on the link between N5 and p (N5), a wireless link that cannot be selected is subsequently determined, and the determined wireless link is held as a tabu list T (N5). Since p (N5) is N1 (via communication method A), T (N5) is {via communication method A (N1ＮN2, N1⇔N5, N5⇔N6, N5⇔N9, N2⇔N3, N2⇔N6 , N6⇔N7, N6⇔N10, N9⇔N10, N9⇔N13)}.

  (Step S3034) The following processing is executed for all wireless communication devices v (v is vεN (w = N5) ∩U = {N1, N6, N9} ∩U = {N6, N9}). “Dist (w) + cost (w, v)” is smaller than dist_temp (v), and the link between the wireless communication device w and the wireless communication device v must be included in the target tabu list T (N5). For example, dist_temp (v) is set to dist (w) + cost (w, v), and p (v) is set to w.

  The process of step S3034 will be specifically described. First, processing is executed for a case where the wireless communication apparatus number is small and v is N6. cost (N5, N6) varies depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A is included in the taboo list, it cannot be selected. The next lowest cost via communication method B is not included in the tabu list, but dist (N5) + cost (N5, N6) = 3, which is the same value as dist_temp (N6) = 3, so the condition is not satisfied. . Therefore, no update is performed.

  Subsequently, the process is executed also when v is N9. cost (N5, N9) varies depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A is included in the taboo list, it cannot be selected. The next lowest cost communication method B is not included in the tabu list, and dist (N5) + cost (N5, N9) = 3, which is smaller than dist_temp (N9) = ∞, which satisfies the condition. Therefore, dist_temp (N9) is set to 3, and p (N9) = N5 (via communication method B). Since the processing is executed for all the calculation target wireless communication devices v (vεN (N5) ∩U), the next route (wireless communication device) is searched.

  (Step S303 (third time)) In order to determine the route, the processes of Steps S3031 to S3034 are repeated until the wireless communication device N10 and the wireless communication device N16 that are the destination wireless communication devices d are reached.

  (Step S3031) From the set U = {N3, N4, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16}, the wireless communication device w having the smallest dist_temp (w) select. At present, dist_temp (N3), dist_temp (N6), and dist_temp (N9) are 3, and other dist_temp (v) is ∞ (infinite). Among them, the wireless communication device N3 having a smaller wireless communication device number is selected as the wireless communication device w.

  (Step S3032) dist (w = N3) is set to dist_temp (N3) = 3. Further, U is set to V- {w = N3}. That is, U is set to {N4, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16}.

  (Step S3033) Based on the link between N3 and p (N3), a wireless link that cannot be selected is determined, and the determined wireless link is held as a tabu list T (N3). Since p (N3) is N2 (via communication method B), T (N3) is changed to {via communication method B (N1⇔N2, N2⇔N3, N2⇔N6, N3⇔N4, N3⇔N7, N1⇔N5 , N5⇔N6, N6⇔N7, N6⇔N10, N4⇔N8, N7⇔N8, N7⇔N11)}.

  (Step S3034) The following processing is executed for all wireless communication apparatuses v (v is vεN (w = N3) ∩U = {N2, N4, N7} ∩U = {N4, N7}). “Dist (w) + cost (w, v)” is smaller than dist_temp (v), and the link between the wireless communication device w and the wireless communication device v is a target tabu list T (N3) and T (p ( N3)) = T (N2), if not included, dist_temp (v) is set to dist (w) + cost (w, v), and p (v) is set to w.

  The process of step S3034 will be specifically described. First, processing is executed for a case where the wireless communication apparatus number is small and v is N4. cost (N3, N4) varies depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A is included in the tabu list T (N2), it cannot be selected. Further, the communication method B cannot be selected because it is included in the tabu list T (N3). The next lowest cost communication method C is not included in the tabu list, and dist (N3) + cost (N3, N4) = 6, which is smaller than dist_temp (N4) = ∞, which satisfies the condition. Therefore, dist_temp (N4) is set to 6, and p (N4) = N3 (via communication method C).

  Subsequently, the process is executed also when v is N7. cost (N3, N7) differs depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A is included in the tabu list T (N2), it cannot be selected. Further, the communication method B cannot be selected because it is included in the tabu list T (N3). The next lowest cost communication method C is not included in the tabu list, and dist (N3) + cost (N3, N7) = 6, which is smaller than dist_temp (N7) = ∞, which satisfies the condition. Therefore, dist_temp (N7) is set to 6, and p (N7) = N3 (via communication method C). Since the processing is executed for all the calculation target wireless communication devices v (vεN (N3) ∩U), the next route (wireless communication device) is searched.

  (Step S303 (fourth time)) In order to determine the route, the processes of Steps S3031 to S3034 are repeated until the wireless communication device N10 and the wireless communication device N16 that are the destination wireless communication devices d are reached.

  (Step S3031) The wireless communication device w that minimizes dist_temp (w) is selected from the set U = {N4, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16}. . At present, dist_temp (N6) and dist_temp (N9) are 3, dist_temp (N4) and dist_temp (N6) are 6, and other dist_temp (v) is ∞ (infinite), so the cost is minimum. The wireless communication device N6 having a smaller wireless communication device number is selected as the wireless communication device w from among the wireless communication device candidates.

  (Step S3032) dist (w = N6) is set to dist_temp (N6) = 3. Further, U is U- {w = N6}. That is, U is set to {N4, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16}.

  (Step S3033) Based on the link between N6 and p (N6), a wireless link that cannot be selected is determined thereafter, and the determined wireless link is held as a tabu list T (N6). Since p (N6) is N2 (via communication method B), T (N6) is changed to {via communication method B (N1⇔N2, N2⇔N3, N2⇔N6, N5⇔N6, N6⇔N7, N6⇔N10). , N1⇔N5, N3⇔N4, N3⇔N7, N5⇔N9, N7⇔N8, N7⇔N11, N9⇔N10, N10⇔N11, N10⇔N14)}.

  (Step S3034) The following processing is executed for all wireless communication devices v (v is vεN (w = N6) ∩U = {N2, N5, N7, N10} ∩U = {N7, N10}). To do. “Dist (w) + cost (w, v)” is smaller than dist_temp (v), and the link between the wireless communication device w and the wireless communication device v is a target tabu list T (N6) and T (p ( N3)) = T (N2), if not included, dist_temp (v) is set to dist (w) + cost (w, v), and p (v) is set to w.

  The process of step S3034 will be specifically described. First, processing is executed for a case where the wireless communication apparatus number is small and v is N7. cost (N6, N7) varies depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A is included in the tabu list T (N2), it cannot be selected. Further, since the communication method B is included in the tabu list T (N6), it cannot be selected. The next lowest cost communication method C is not included in the tabu list, but dist (N6) + cost (N6, N7) = 6, which is the same value as dist_temp (N6) = 6, so the condition is not satisfied. . Therefore, no update is performed.

  Subsequently, the process is also executed when v is N10. cost (N6, N10) varies depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A is included in the tabu list T (N2), it cannot be selected. Further, since the communication method B is included in the tabu list T (N6), it cannot be selected. The communication method C having the next lowest cost is not included in the tabu list, and dist (N6) + cost (N6, N10) = 6, which is smaller than dist_temp (N10) = ∞, which satisfies the condition. Therefore, dist_temp (N10) is set to 6, and p (N10) = N6 (via communication method C). Since processing has been executed for all calculation target wireless communication devices v (vεN (N6) ∩U), the next route (wireless communication device) is searched.

  (Step S303 (5th time)) In order to determine the route, the processes of Steps S3031 to S3034 are repeated until the wireless communication device N10 and the wireless communication device N16 that are the destination wireless communication devices d are reached.

  (Step S3031) From the set U = {N4, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16}, the wireless communication device w that minimizes dist_temp (w) is selected. At the present time, dist_temp (N9) is 3, dist_temp (N4), dist_temp (N7), and dist_temp (N10) are 6, and other dist_temp (v) is ∞ (infinite). The wireless communication device N9 that is the wireless communication device candidate that minimizes is selected as the wireless communication device w.

  (Step S3032) dist (w = N9) is set to dist_temp (N9) = 3. Further, U is U- {w = N9}. That is, U is set to {N4, N7, N8, N10, N11, N12, N13, N14, N15, N16}.

  (Step S3033) Based on the link between N9 and p (N9), a wireless link that cannot be selected is subsequently determined, and the determined wireless link is retained as a tabu list T (N9). Since p (N9) is N5 (via communication method B), T (N9) is {via communication method B (N1⇔N5, N5⇔N6, N5⇔N9, N9⇔N10, N9⇔N13, N1⇔N2 , N2⇔N6, N6⇔N7, N6⇔N10, N10⇔N11, N10⇔N14, N13⇔N14)}.

  (Step S3034) The following processing is executed for all wireless communication devices v (v is vεN (w = N9) ∩U = {N5, N10, N13} ∩U = {N10, N13}). “Dist (w) + cost (w, v)” is smaller than dist_temp (v), and the link between the wireless communication device w and the wireless communication device v is a target tabu list T (N9) and T (p ( N9)) = T (N2), if not included, dist_temp (v) is set to dist (w) + cost (w, v), and p (v) is set to w.

  The process of step S3034 will be specifically described. First, processing is executed for a case where the wireless communication apparatus number is small and v is N10. cost (N9, N10) differs depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A is included in the tabu list T (N5), it cannot be selected. Further, since the communication method B is included in the taboo list T (N9), it cannot be selected. The next lowest cost communication method C is not included in the tabu list, but dist (N9) + cost (N9, N10) = 6, which is the same value as dist_temp (N10) = 6, so the condition is not satisfied. . Therefore, no update is performed.

  Subsequently, the process is executed also when v is N13. cost (N9, N13) varies depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A is included in the taboo list, it cannot be selected. The next lowest cost communication method B is not included in the tabu list, and dist (N9) + cost (N9, N13) = 6, which is smaller than dist_temp (N13) = ∞, so the condition is satisfied. Therefore, dist_temp (N13) is set to 3, and p (N13) = N9 (via communication method C). Since the processing is executed for all the calculation target wireless communication devices v (vεN (N9) ∩U), the next route (wireless communication device) is searched.

  (Step S303 (6th time)) In order to determine the route, the processes of Steps S3031 to S3034 are repeated until the wireless communication device N10 and the wireless communication device N16 that are the destination wireless communication devices d are reached.

  (Step S3031) The wireless communication device w that minimizes dist_temp (w) is selected from the set U = {N4, N7, N8, N10, N11, N12, N13, N14, N15, N16}. At present, dist_temp (N4), dist_temp (N7), dist_temp (N10), and dist_temp (N13) are 6, and other dist_temp (v) is ∞ (infinity), so the cost is minimum. Among the wireless communication device candidates, the wireless communication device N4 having a smaller wireless communication device number is selected as the wireless communication device w.

  (Step S3032) dist (w = N4) is set to dist_temp (N4) = 6. Further, U is U- {w = N4}. That is, U is set to {N7, N8, N10, N11, N12, N13, N14, N15, N16}.

  (Step S3033) Based on the link between N4 and p (N4), a wireless link that cannot be selected is subsequently determined, and the determined wireless link is held as a tabu list T (N4). Since p (N4) is N3 (via communication method C), T (N4) is changed to {via communication method C (N2⇔N3, N3⇔N4, N3⇔N7, N4⇔N8, N1⇔N2, N2⇔N6). , N6⇔N7, N7⇔N8, N7⇔N11, N8⇔N12)}.

  (Step S3034) The following processing is executed for all wireless communication devices v (v is vεN (w = N4) ∩U = {N3, N8} ∩U = {N8}). “Dist (w) + cost (w, v)” is smaller than dist_temp (v), and the link between the wireless communication device w and the wireless communication device v is a target tabu list T (N4) and T (p ( N4)) = T (N3) and T (p (p (N4))) = T (p (N3)) = T (N2) if not included, dist_temp (v) is set to dist (w) + cost Let (w, v) and p (v) be w.

  The process of step S3034 will be specifically described. First, processing is executed for a case where the wireless communication apparatus number is small and v is N4. cost (N4, N8) varies depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, the communication method A is not included in the taboo list, and dist (N4) + cost (N4, N8) = 7, which is smaller than dist_temp (N8) = ∞, so the condition is satisfied. Therefore, dist_temp (N8) is set to 7, and p (N8) = N4 (via communication method A). Since processing has been executed for all calculation target wireless communication devices v (vεN (N4) ∩U), the next route (wireless communication device) is searched.

  (Step S303 (Seventh)) In order to determine the route, the processes of Steps S3031 to S3034 are repeated until the wireless communication device N10 and the wireless communication device N16 that are the destination wireless communication devices d are reached.

  (Step S3031) From the set U = {N7, N8, N10, N11, N12, N13, N14, N15, N16}, the wireless communication device w that minimizes dist_temp (w) is selected. At present, dist_temp (N7), dist_temp (N10), and dist_temp (N13) are 6, dist_temp (N8) is 7, and other dist_temp (v) is ∞ (infinite), so the cost is low. The wireless communication device N7 having the smallest wireless communication device number is selected as the wireless communication device w from among the wireless communication device candidates having the smallest.

  (Step S3032) dist (w = N7) is set to dist_temp (N7) = 6. Further, U is U- {w = N7}. That is, U is set to {N8, N10, N11, N12, N13, N14, N15, N16}.

  (Step S3033) Based on the link between N7 and p (N7), a wireless link that cannot be selected is subsequently determined, and the determined wireless link is held as a tabu list T (N7). Since p (N7) is N3 (via communication method C), T (N7) is changed to {via communication method C (N2⇔N3, N3⇔N4, N3⇔N7, N6⇔N7, N7⇔N8, N7⇔N11). , N1⇔N2, N2⇔N6, N4⇔N8, N5⇔N6, N6⇔N10, N8⇔N12, N10⇔N11, N11⇔N12, N11⇔N15)}.

  (Step S3034) The following processing is executed for all wireless communication devices v (v is vεN (w = N7) ∩U = {N3, N5, N8, N11} ∩U = {N8, N11}). To do. “Dist (w) + cost (w, v)” is smaller than dist_temp (v), and the link between the wireless communication device w and the wireless communication device v is a target tabu list T (N7) and T ((N3 ) And T (N2), dist_temp (v) is set to dist (w) + cost (w, v), and p (v) is set to w.

  The process of step S3034 will be specifically described. First, processing is executed for a case where the wireless communication apparatus number is small and v is N8. cost (N7, N8) differs depending on the communication method, and is 1 through the communication method A, 2 through the communication method B, and 3 through the communication method C. Here, although the communication method A is not included in the tabu list, dist (N7) + cost (N7, N8) = 7 and the same value as dist_temp (N8) = 7 does not satisfy the condition. Therefore, no update is performed.

  Next, a process is performed when v is N11. cost (N7, N11) differs depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, the communication method A is not included in the tabu list, and dist (N7) + cost (N7, N11) = 7, which is smaller than dist_temp (N11) = ∞, which satisfies the condition. Therefore, dist_temp (N11) is set to 7, and p (N11) = N7 (via communication method A). Since processing has been executed for all calculation target wireless communication devices v (vεN (N7) ∩U), the next route (wireless communication device) is searched.

  (Step S303 (8th time)) In order to determine the route, the processes of Steps S3031 to S3034 are repeated until the wireless communication device N10 and the wireless communication device N16 that are the destination wireless communication devices d are reached.

  (Step S3031) The wireless communication device w that minimizes dist_temp (w) is selected from the set U = {N8, N10, N11, N12, N13, N14, N15, N16}. At present, dist_temp (N10) and dist_temp (N13) are 6, dist_temp (N8) and dist_temp (N11) are 7, and other dist_temp (v) is ∞ (infinite), so the cost is low. The wireless communication device N10 having the smallest wireless communication device number is selected as the wireless communication device w from among the wireless communication device candidates having the smallest.

  (Step S3032) Dist (w = N10) is set to dist_temp (N10) = 6. Further, U is U- {w = N10}. That is, U is set to {N8, N11, N12, N13, N14, N15, N16}.

(Step S3033) Based on the link between N10 and p (N10), a wireless link that cannot be selected is subsequently determined, and the determined wireless link is held as a tabu list T (N10). Since p (N10) is N6 (via communication method C), T (N10) is changed to {via communication method (N2⇔N6, N5⇔N6, N6⇔N7, N6⇔N10, N9⇔N10, N10⇔N11, N10 N14, N1 N2, N2 N3, N1 N5, N5 N9, N3 N7, N7 N8, N7 N11, N9 N13, N11 N12, N11 N15, N13 N14, N14 N N15)}.

  (Step S3034) The following processing is executed for all wireless communication devices v (v is vεN (w = N10) ∩U = {N6, N9, N11, N14} ∩U = {N11, N14}). To do. “Dist (w) + cost (w, v)” is smaller than dist_temp (v), and the tabu lists T (N10) and T (N6) are targets for the link between the wireless communication device w and the wireless communication device v. And T (N2), dist_temp (v) is set to dist (w) + cost (w, v), and p (v) is set to w.

  The process of step S3034 will be specifically described. First, processing is executed for a case where the wireless communication apparatus number is small and v is N11. cost (N10, N11) varies depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, the communication method A is not included in the tabu list, but dist (N10) + cost (N10, N11) = 7, which is the same value as dist_temp (N8) = 7, so the condition is not satisfied. Therefore, no update is performed.

  Next, the process is executed when v is N14. cost (N10, N14) differs depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, the communication method A is not included in the tabu list, and dist (N10) + cost (N10, N14) = 7, which is smaller than dist_temp (N14) = ∞, which satisfies the condition. Therefore, dist_temp (N14) is set to 7, and p (N14) = N10 (via communication method A). Since the processing is executed for all the calculation target wireless communication devices v (vεN (N10) ∩U), the next route (wireless communication device) is searched.

  Since the wireless communication device N10 is connected to the gateway, it is one of the destination wireless communication devices, and the path from the wireless communication device N1 to the wireless communication device N10 is p (N10), p (p (n10)),. .., N1 and the reverse order of the route followed in the above calculation. That is, the route from the wireless communication device N1 to the wireless communication device N10 is N1⇒ (via communication method A) ⇒N2⇒ (via communication method B) ⇒N6⇒ (via communication method C) ⇒N10. In this case, the cost is 6 and the number of hops is 3. Since the route to the wireless communication device N16, which is another destination wireless communication device, is not yet determined, the calculation is continued.

  FIG. 12 is a diagram illustrating a route from the start point wireless communication apparatus to the destination wireless communication apparatus in the present embodiment. The configuration of the wireless communication system is the same as that shown in FIG. In the illustrated example, the route from the wireless communication device N1 to the wireless communication device N10 is indicated by arrows 120 to 122, and the route from the wireless communication device N1 to the wireless communication device N10 is N1⇒ (via communication method A) ⇒ N2⇒ (via communication method B) ⇒N6⇒ (via communication method C) ⇒N10.

  Similar to the procedure described above, the route from the wireless communication device N1 to the wireless communication device N16 can be similarly obtained by repeating the process of step S303. In the example of this embodiment, the route from the wireless communication device N1 to the wireless communication device N16 is N1⇒ (via communication method A) ⇒N2⇒ (via communication method B) ⇒N3⇒ (via communication method C) ⇒N4⇒ ( Via communication system A) → N8 → (via communication system B) → N12 → (via communication system C) → N16. In this case, the cost is 12 and the number of hops is 6.

  FIG. 13 is a diagram illustrating a route from the start point wireless communication device to the destination wireless communication device. The configuration of the wireless communication system is the same as that shown in FIG. In the illustrated example, the route from the wireless communication device N1 to the wireless communication device N16 is indicated by arrows 130 to 135, and the route from the wireless communication device N1 to the wireless communication device N16 is N1⇒ (via communication method A) ⇒ N2⇒ (via communication method B) ⇒N3⇒ (via communication method C) ⇒N4⇒ (via communication method A) ⇒N8⇒ (via communication method B) ⇒N12⇒ (via communication method C) ⇒N16.

  Thus, the calculation from the wireless communication device N1 to all the destination wireless communication devices is completed. The evaluation value of each determined route is calculated and compared. When the cost value is used as the evaluation value, the cost of the route from the wireless communication device N1 to the wireless communication device N10 is 6, and the cost from the wireless communication device N1 to the wireless communication device N16 is 12. Therefore, in order to select a wireless communication device with good cost, the gateway to which the wireless communication device N1 is connected is determined as the gateway to which the wireless communication device N10 is connected.

  As another example, the number of hops may be used as the evaluation value. In this case, the number of hops in the path from the wireless communication device N1 to the wireless communication device N10 is 3, and the number of hops from the wireless communication device N1 to the wireless communication device N16 is 6. Therefore, in order to select a wireless communication device with a small number of hops, the gateway to which the wireless communication device N1 is connected is determined as the gateway to which the wireless communication device N10 is connected.

  As described above, the route to the gateway used by the wireless communication device N1 is determined as N1⇒ (via communication method A) ⇒N2⇒ (via communication method B) ⇒N6⇒ (via communication method C) ⇒N10. The route from the wireless communication device N3 to the gateway is calculated using the route as an already assigned route (flow). At this time, restrictions on usable radio links are tabu lists T (N2), T (N6), and T (N10) on the determined route.

<Calculation of route from wireless communication device N3 to each gateway>
Since the route from the wireless communication device N1 to the gateway has been determined, next, the route from the wireless communication device N3 to the wireless communication device N10 and the wireless communication device N16 connected to the gateway is calculated according to the calculation order described above. Further, the route is calculated in consideration of the influence of the wireless communication used in the route from the wireless communication device N1 to the gateway.

  First, variables are initialized as a calculation preparation. Specifically, the wireless communication device set V is set as {N1, N2, N3, N4, N5, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16}. The starting point wireless communication device S is set to N3.

  The adjacent wireless communication device N (N1) of the wireless communication device N1 is set as {N2, N5}. The adjacent wireless communication device N (N2) of the wireless communication device N2 is set as {N1, N3, N6}. The adjacent wireless communication device N (N3) of the wireless communication device N3 is set as {N2, N4, N7}. The adjacent wireless communication device N (N4) of the wireless communication device N4 is set as {N3, N8}. The adjacent wireless communication device N (N5) of the wireless communication device N5 is set as {N1, N6, N9}. The adjacent wireless communication device N (N6) of the wireless communication device N6 is set as {N2, N5, N7, N10}. The adjacent wireless communication device N (N7) of the wireless communication device N7 is set as {N3, N5, N8, N11}. The adjacent wireless communication device N (N8) of the wireless communication device N8 is set as {N4, N7, N12}.

  The adjacent wireless communication device N (N9) of the wireless communication device N9 is set as {N5, N10, N13}. The adjacent wireless communication device N (N10) of the wireless communication device N10 is set as {N6, N9, N11, N14}. The adjacent wireless communication device N (N11) of the wireless communication device N11 is set as {N7, N10, N12, N15}. The adjacent wireless communication device N (N12) of the wireless communication device N12 is set as {N8, N11, N16}. The adjacent wireless communication device N (N13) of the wireless communication device N13 is set as {N9, N14}. The adjacent wireless communication device N (N14) of the wireless communication device N14 is set as {N10, N13, N15}. The adjacent wireless communication device N (N15) of the wireless communication device N15 is set as {N11, N14, N16}. The adjacent wireless communication device N (N16) of the wireless communication device N16 is set as {N12, N15}.

  The cost of the link between the wireless communication device x and the wireless communication device y is set for each communication unit. The cost is different for each wireless system. When the cost of the wireless system A is 1, the cost of the wireless system B is 2, and the cost of the wireless system C is 3, the cost cost (x, y) when using the communication unit A13 is calculated. 1 is set, the cost cost (x, y) when using the communication unit B14 is set to 2, and the cost cost (x, y) when using the communication unit C15 is set to 3.

  The threshold used for determining the influence value of interference / collision is set to 1. In addition, when the above-described policies (1) to (8) are applicable, the constant is set to 1. Thereby, it becomes a policy which restrict | limits the utilization of the radio | wireless system about the radio | wireless system applicable to at least one of the policies of (1)-(8).

Then, the process of step S301-step S303 is implemented.
(Step S301) Steps S3011 to S3013, which are processes for initializing parameters used in the Dijkstra method, are performed.
(Step S3011) p (N3) is set to = φ (empty set). Also, dist (N1) is set to 0. Moreover, let U be V- {N3}. That is, U is set to {N1, N2, N4, N5, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16}.

(Step S3012) For all wireless communication devices v (where vεU), dist_temp (v) is set to ∞ (infinity).
(Step S3013) A link that cannot be selected by a route that has already been assigned is managed as a tabu list T (already assigned). The route from the wireless communication device N1 to the wireless communication device N10 has already been assigned, and the contents of the tabu lists T (N2), T (N6), and T (N10) of this route are reflected in T (already assigned).

  That is, T (allocated) = {via communication system A (N1ＮN2, N1⇔N5, N2⇔N3, N2⇔N6, N5⇔N6, N5⇔N9, N3⇔N4, N3⇔N7, N6⇔N7, N6⇔N10) via communication method B (N1⇔N2, N2⇔N3, N2⇔N6, N5⇔N6, N6⇔N7, N6⇔N10, N1⇔N5, N3⇔N4, N3⇔N7, N5⇔N9, N7 ⇔N8, N7 ⇔ N11, N9 ⇔ N10, N10 ⇔ N11, N10 経 由 N14) via communication method C (N2 ⇔ N6, N5 ⇔ N6, N6 ⇔ N7, N6 ⇔ N10, N9 ⇔ N10, N10 ⇔ N11, N10 ⇔ N14, N1 N2, N2 N3, N1 N5, N5 N9, N3 N7, N7 N8, N7 N11, N9 N13, N11 N12, N11 N15, N13 N14, N14 N15) }.

  (Step S302) The cost from the starting wireless communication device s (wireless communication device N3) to the adjacent wireless communication device v is calculated. Dist_temp (v) of the wireless communication device v (vεN (N3) = {N2, N4, N7}) adjacent to the wireless communication device N1 is calculated. The cost (N3, N2) is ∞ (infinite) because any of the communication methods A, B, and C is included in the tabu list. Therefore, dist_temp (N2) is set to ∞.

  The cost (N3, N4) is 3 because the communication method A and the communication method B are included in the tabu list and the wireless method C is used. Therefore, dist_temp (N4) is set to 3. Further, p (N4) = N3 (via communication method C).

  cost (N3, N7) is ∞ (infinite) because any of communication method A, communication method B, and communication method C is included in the tabu list. Therefore, dist_temp (N7) is set to ∞.

  (Step S303 (first time)) A route from the start wireless communication device s to the destination wireless communication device d is determined. In order to determine the route, the processes in steps S3031 to S3034 are repeated until the wireless communication device N10 and the wireless communication device N16 that are the destination wireless communication devices d are reached.

  (Step S3031) Wireless in which dist_temp (w) is the minimum among the set U = {N1, N2, N4, N5, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16} A communication device w is selected. At present, dist_temp (N4) is 3, and other dist_temp (v) is ∞ (infinity), so the wireless communication device N4 with the lowest cost is selected as the wireless communication device w.

  (Step S3032) Dist (w = N4) is set to dist_temp (N4) = 3. U is U- {N4}. That is, U is set to {N1, N2, N5, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16}.

  (Step S3033) Based on the link between N4 and p (N4), a wireless link that cannot be selected is subsequently determined, and the determined wireless link is held as a tabu list T (N4). Since p (N4) is N3 (via communication method C), T (N4) is {via communication method C (N1ＮN2, N2ＮN3, N2⇔N6, N3⇔N4, N3⇔N7, N4⇔N8 , N6⇔N7, N7⇔N8, N7⇔N11, N8⇔N12)}.

  (Step S3034) The following processing is executed for all wireless communication devices v (vεN (w = N4) ∩U = {N8}). “Dist (w) + cost (w, v)” is smaller than dist_temp (v), and the link between the wireless communication device w and the wireless communication device v is a target tabu list T (allocated) and T (N4 ), Dist_temp (v) is set to dist (w) + cost (w, v), and p (v) is set to w.

  The process of step S3034 will be specifically described. First, processing is executed for a case where the wireless communication apparatus number is small and v is N8. cost (N4, N8) varies depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, the communication method A is not included in the taboo list, and dist (N4) + cost (N4, N8) = 4, which is smaller than dist_temp (N8) = ∞, which satisfies the condition. Therefore, dist_temp (N8) is set to 4, and p (N8) = N4 (via communication method A). Since processing has been executed for all calculation target wireless communication devices v (vεN (N4) ∩U), the next route (wireless communication device) is searched.

  (Step S303 (second time)) In order to determine the route, the processes of Steps S3031 to S3034 are repeated until the wireless communication device N10 and the wireless communication device N16 that are the destination wireless communication devices d are reached.

  (Step S3031) Wireless communication apparatus in which dist_temp (w) is minimized from among set U = {N1, N2, N5, N6, N7, N8, N9, N10, N11, N12, N13, N14, N15, N16} Select w. At present, dist_temp (N8) is 4, and other dist_temp (v) is ∞ (infinity), so the wireless communication device N8 with the lowest cost is selected as the wireless communication device w.

  (Step S3032) dist (w = N8) is set to dist_temp (N8) = 4. U is U- {w = N8}. That is, U is set to {N1, N2, N5, N6, N7, N9, N10, N11, N12, N13, N14, N15, N16}.

  (Step S3033) Based on the link between N8 and p (N8), a wireless link that cannot be selected is determined thereafter, and the determined wireless link is held as a tabu list T (N8). Since p (N8) is N4 (via communication method A), T (N8) is changed to {via communication method A (N2⇔N3, N3⇔N4, N3⇔N7, N4⇔N8, N6⇔N7, N7⇔N8 , N7⇔N11, N8⇔N12, N11⇔N12, N12⇔N16)}.

  (Step S3034) The following processing is executed for all wireless communication devices v (vεN (w = N8) ∩U = {N4, N7, N12} ∩U = {N7, N12}). “Dist (w) + cost (w, v)” is smaller than dist_temp (v), and the link between the wireless communication device w and the wireless communication device v is a target tabu list T (allocated) and T (N8 ) And T (N4), dist_temp (v) is set to dist (w) + cost (w, v), and p (v) is set to w.

  The process of step S3034 will be specifically described. First, processing is executed for a case where the wireless communication apparatus number is small and v is N7. cost (N8, N7) differs depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A is included in the taboo list, it cannot be selected. The next lowest cost communication method B is not included in the taboo list, and dist (N8) + cost (N8, N12) = 6, which is smaller than dist_temp (N12) = ∞, which satisfies the condition. Therefore, dist_temp (N12) is set to 6, and p (N12) = N8 (via communication method B).

  (Step S303 (third time)) In order to determine the route, the processes of Steps S3031 to S3034 are repeated until the wireless communication device N10 and the wireless communication device N16 that are the destination wireless communication devices d are reached.

  (Step S3031) From the set U = {N1, N2, N5, N6, N7, N9, N10, N11, N12, N13, N14, N15, N16}, the wireless communication device w with the smallest dist_temp (w) is selected. select. At present, dist_temp (N12) is 6, and other dist_temp (v) is ∞ (infinity), so the wireless communication device N12 with the lowest cost is selected as the wireless communication device w.

  (Step S3032) dist (w = N12) is set to dist_temp (N12) = 6. Further, U is U- {w = N12}. That is, U is set to {N1, N2, N5, N6, N7, N9, N10, N11, N13, N14, N15, N16}.

  (Step S3033) Based on the link between N12 and p (N12), a wireless link that cannot be selected is subsequently determined, and the determined wireless link is held as a tabu list T (N12). Since p (N12) is N8 (via communication method B), T (N12) is changed to {via communication method B (N3⇔N4, N3⇔N7, N4⇔N8, N6⇔N7, N7⇔N8, N7⇔N11). , N8⇔N12, N10⇔N11, N11⇔N12, N11⇔N15, N12⇔N16, N15⇔N16)}.

  (Step S3034) The following processing is executed for all wireless communication devices v (vεN (w = N12) ∩U = {N8, N11, N16} ∩U = {N11, N16}). “Dist (w) + cost (w, v)” is smaller than dist_temp (v), and the link between the wireless communication device w and the wireless communication device v is a target tabu list T (allocated) and T ( N12), T (N8), and T (N4) are not included, dist_temp (v) is set to dist (w) + cost (w, v), and p (v) is set to w.

  The process of step S3034 will be specifically described. First, processing is executed for a case where the wireless communication apparatus number is small and v is N11. cost (N12, N11) varies depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A, the communication method B, and the communication method C are included in the tabu list, they cannot be selected. Therefore, no update is performed.

  Subsequently, the process is executed also when v is N16. cost (N12, N16) differs depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A and the communication method B are included in the tabu list, they cannot be selected. The next lowest cost communication method C is not included in the taboo list, and dist (N12) + cost (N12, N16) = 9, which is smaller than dist_temp (N16) = ∞, which satisfies the condition. Therefore, dist_temp (N16) is set to 9, and p (N16) = N12 (via communication method C). Since the processing is executed for all the calculation target wireless communication devices v (vεN (N12) ∩U), the next route (wireless communication device) is searched.

  (Step S303 (fourth time)) In order to determine the route, the processes of Steps S3031 to S3034 are repeated until the wireless communication device N10 and the wireless communication device N16 that are the destination wireless communication devices d are reached.

  (Step S3031) The wireless communication device w that minimizes dist_temp (w) is selected from the set U = {N1, N2, N5, N6, N7, N9, N10, N11, N13, N14, N15, N16}. . At present, dist_temp (N16) is 9, and other dist_temp (v) is ∞ (infinite), so the wireless communication device N16 with the lowest cost is selected as the wireless communication device w.

  (Step S3032) dist (w = N16) is set to dist_temp (N16) = 9. Further, U is U- {w = N16}. That is, U is set to {N1, N2, N5, N6, N7, N9, N10, N11, N13, N14, N15}.

  (Step S3033) Based on the link between N16 and p (N16), a wireless link that cannot be selected is subsequently determined, and the determined wireless link is held as a tabu list T (N16). Since p (N16) is N12 (via communication method C), T (N16) is {via communication method C (N4ＮN8, N7⇔N8, N8⇔N12, N10⇔N11, N11⇔N12, N11⇔N15). , N12⇔N16, N14⇔N15, N15⇔N16)}.

  (Step S3034) The following processing is executed for all wireless communication devices v (vεN (w = N16) ∩U = {N12, N15} ∩U = {N15}). “Dist (w) + cost (w, v)” is smaller than dist_temp (v), and the link between the wireless communication device w and the wireless communication device v is a target tabu list T (allocated) and T ( N16), T (N12), T (N8), and T (N4) are not included, dist_temp (v) is set to dist (w) + cost (w, v), and p (v) is set to w And

  The process of step S3034 will be specifically described. First, the process is executed for a case where the wireless communication apparatus number is small and v is N15. The cost (N16, N15) differs depending on the communication method, and is 1 through the communication method A, 2 through the communication method B, and 3 through the communication method C. Here, the communication method A is not included in the taboo list, and dist (N16) + cost (N16, N15) = 10, which is smaller than dist_temp (N15) = ∞, which satisfies the condition. Therefore, dist_temp (N15) is set to 10, and p (N15) = N16 (via communication method A).

  The wireless communication device N16 is one of the destination wireless communication devices because it is connected to the gateway, and the route from the wireless communication device N3 to the wireless communication device N16 is N3⇒ (via communication method C) ⇒N4⇒ (communication method A) Via) ⇒ N8 ⇒ (via communication method B) ⇒ N12 ⇒ (via communication method C) ⇒ N16. In this case, the cost is 9 and the number of hops is 4. Since the route to the wireless communication device N10, which is another destination wireless communication device, has not yet been determined, the calculation is continued.

  FIG. 14 is a diagram illustrating a route from the start point wireless communication apparatus to the destination wireless communication apparatus in the present embodiment. The configuration of the wireless communication system is the same as that shown in FIG. In the illustrated example, the route from the wireless communication device N3 to the wireless communication device N16 is indicated by arrows 140 to 143, and the route from the wireless communication device N3 to the wireless communication device N16 is N3⇒ (via communication method C) ⇒ N4⇒ (via communication method A) ⇒N8⇒ (via communication method B) ⇒N12⇒ (via communication method C) ⇒N16.

  (Step S303 (fifth)) In order to determine the route, the processes of Steps S3031 to S3034 are repeated until the wireless communication device N10 that is the destination wireless communication device d is reached.

  (Step S3031) From the set U = {N1, N2, N5, N6, N7, N9, N10, N11, N13, N14, N15}, the wireless communication device w that minimizes dist_temp (w) is selected. At present, dist_temp (N15) is 10, and other dist_temp (v) is ∞ (infinite), so the wireless communication device N15 with the lowest cost is selected as the wireless communication device w.

  (Step S3032) dist (w = N15) is set to dist_temp (N15) = 10. U is U- {w = N15}. That is, U is set to {N1, N2, N5, N6, N7, N9, N10, N11, N13, N14}.

  (Step S3033) Based on the link between N15 and p (N15), a wireless link that cannot be selected is determined thereafter, and the determined wireless link is held as a tabu list T (N15). Since p (N15) is N16 (via communication method A), T (N15) is changed to {via communication method A (N7⇔N11, N8⇔N12, N10⇔N11, N10⇔N14, N11⇔N12, N11⇔N15). , N12⇔N16, N13⇔N14, N14⇔N15, N15⇔N16)}.

  (Step S3034) The following processing is executed for all wireless communication devices v (vεN (w = N15) ∩U = {N11, N14, N16} ∩U = {N11, N14}). “Dist (w) + cost (w, v)” is smaller than dist_temp (v), and the link between the wireless communication device w and the wireless communication device v is a target tabu list T (allocated) and T ( N15), T (N16), T (N12), T (N8), and T (N4), if not included, dist_temp (v) is set to dist (w) + cost (w, v), Let p (v) be w.

  The process of step S3034 will be specifically described. First, processing is executed for a case where the wireless communication apparatus number is small and v is N11. cost (N15, N11) differs depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since any of the communication method A, the communication method B, and the communication method C is included in the tabu list, it becomes ∞ (infinity). Therefore, dist_temp (N11) is set to ∞.

  Next, the process is executed when v is N14. cost (N15, N14) differs depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A is included in the taboo list, it cannot be selected. The communication method B is not included in the tabu list, and dist (N15) + cost (N15, N14) = 12, which is smaller than dist_temp (N14) = ∞, so the condition is satisfied. Therefore, dist_temp (N14) is set to 12, and p (N14) = N15 (via communication method B). Since processing has been executed for all calculation target wireless communication devices v (vεN (N15) ∩U), the next route (wireless communication device) is searched.

  (Step S303 (6th time)) In order to determine the route, the processes of Steps S3031 to S3034 are repeated until the wireless communication device N10 that is the destination wireless communication device d is reached.

  (Step S3031) The wireless communication device w that minimizes dist_temp (w) is selected from the set U = {N1, N2, N5, N6, N7, N9, N10, N11, N13, N14}. At present, dist_temp (N14) is 12, and other dist_temp (v) is ∞ (infinity), so the wireless communication device N14 with the lowest cost is selected as the wireless communication device w.

  (Step S3032) dist (w = N14) is set to dist_temp (N14) = 12. U is U- {w = N15}. That is, U is set to {N1, N2, N5, N6, N7, N9, N10, N11, N13}.

  (Step S3033) Based on the link between N14 and p (N14), a wireless link that cannot be selected is subsequently determined, and the determined wireless link is held as a tabu list T (N14). Since p (N14) is N15 (via communication method B), T (N14) is changed to {via communication method B (N6⇔N10, N7⇔N11, N9⇔N10, N9⇔N13, N10⇔N11, N10⇔N14). , N11⇔N12, N11⇔N15, N12⇔N16, N13 ， N14, N14⇔N15, N15⇔N16)}.

  (Step S3034) The following processing is executed for all wireless communication devices v (vεN (w = N14) ∩U = {N10, N13, N15} ∩U = {N10, N13}). “Dist (w) + cost (w, v)” is smaller than dist_temp (v), and the link between the wireless communication device w and the wireless communication device v is a target tabu list T (N6) and T (p ( N3)) = T (N2), if not included, dist_temp (v) is set to dist (w) + cost (w, v), and p (v) is set to w.

  The process of step S3034 will be specifically described. First, processing is executed for a case where the wireless communication apparatus number is small and v is N10. cost (N14, N10) varies depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A, the communication method B, and the communication method C are included in the tabu list, they cannot be selected. Therefore, no update is performed.

  Next, the process is executed when v is N13. cost (N14, N113) differs depending on the communication method, and is 1 through communication method A, 2 through communication method B, and 3 through communication method C. Here, since the communication method A, the communication method B, and the communication method C are included in the tabu list, they cannot be selected. Therefore, no update is performed. Since the process is executed for all the calculation target wireless communication devices v (vεN (N14) ∩U), the next route (wireless communication device) is searched.

  (Step S303 (Seventh)) In order to determine the route, the processes of Steps S3031 to S3034 are repeatedly performed until the wireless communication device N10 that is the destination wireless communication device d is reached.

  (Step S3031) The wireless communication device w that minimizes dist_temp (w) is selected from the set U = {N1, N2, N5, N6, N7, N9, N10, N11, N13}. Since all dist_temp (v) is ∞ (infinite) at the present time, the calculation is terminated.

  According to the above-described procedure, the control unit 11 determines the route from the wireless communication device N3 to the wireless communication device N16, but ends the calculation because it can be found that the route from the wireless communication device N3 to the wireless communication device N10 is not found. . After the calculation is completed, the evaluation value of each determined route is calculated and compared. When the cost value is used as the evaluation value, the cost of the path from the wireless communication device N3 to the wireless communication device N10 is ∞, and the cost from the wireless communication device N3 to the wireless communication device N16 is 9. Therefore, in order to select a wireless communication device with good cost, the gateway to which the wireless communication device N3 is connected is determined as the gateway to which the wireless communication device N16 is connected.

  As another example, the number of hops may be used as the evaluation value. In this case, the number of hops in the path from the wireless communication device N3 to the wireless communication device N10 is ∞, and the number of hops from the wireless communication device N3 to the wireless communication device N16 is 4. Therefore, in order to select a wireless communication device with a small number of hops, the gateway to which the wireless communication device N3 is connected is determined as the gateway to which the wireless communication device N16 is connected.

  FIG. 15 is a diagram showing a route from the start point wireless communication apparatus to the destination wireless communication apparatus in the present embodiment. The configuration of the wireless communication system is the same as that shown in FIG. In the illustrated example, the route from the wireless communication device N1 to the wireless communication device N10 is indicated by arrows 150 to 152, and the route from the wireless communication device N1 to the wireless communication device N10 is N1⇒ (via communication method A) ⇒ N2⇒ (via communication method B) ⇒N6⇒ (via communication method C) ⇒N10. The route from the wireless communication device N3 to the wireless communication device N16 is indicated by arrows 153 to 156, and the route from the wireless communication device N3 to the wireless communication device N16 is N3⇒ (via communication method C) ⇒N4⇒ ( Via communication system A) → N8 → (via communication system B) → N12 → (via communication system C) → N16.

  The route shown in FIG. 15 is a route that reflects restrictions in consideration of radio interference and collision between routes in the present embodiment. As described above, according to the present embodiment, it is possible to further suppress the influence of collision between radio links and interference when the radio system is switched and used in cognitive radio or the like. Moreover, since the influence of collision and interference between wireless links can be suppressed, it is possible to provide each wireless communication device with communication with a high-quality core network.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

  For example, in this embodiment, the storage unit stores a wireless communication route that cannot be used by each wireless communication device as a tabu list, and the control unit determines the route in consideration of the tabu list. The storage unit may store a wireless communication route that can be used by the wireless communication device as an available list, and the control unit may determine the route in consideration of the available list.

It is the figure which showed the structure of the radio | wireless communication apparatus (node) in one Embodiment of this invention. It is the figure which showed the structural example of the radio | wireless communications system in this embodiment. It is the figure which showed an example of the format of the information contained in the beacon which the radio | wireless communication apparatus in this embodiment transmits. It is the figure which showed an example of the format of the adjacent radio | wireless communication apparatus table in this embodiment. It is the figure which showed an example of the format of the information contained in the topology information packet which the radio | wireless communication apparatus in this embodiment transmits. It is the figure which showed an example of the format of the topology information table which the memory | storage part of the radio | wireless communication apparatus in this embodiment memorize | stores. It is the flowchart which showed the calculation procedure of the path | route from the radio | wireless communication apparatus in this embodiment to a gateway. It is the figure which showed a part of structure of the radio | wireless communications system in this embodiment. It is the figure which showed a part of structure of the radio | wireless communications system in this embodiment. It is the figure which showed a part of structure of the radio | wireless communications system in this embodiment. It is the figure which showed the path | route from the starting point radio | wireless communication apparatus in this embodiment to a destination radio | wireless communication apparatus. It is the figure which showed the path | route from the starting point radio | wireless communication apparatus in this embodiment to a destination radio | wireless communication apparatus. It is the figure which showed the path | route from the starting point radio | wireless communication apparatus in this embodiment to a destination radio | wireless communication apparatus. It is the figure which showed the path | route from the starting point radio | wireless communication apparatus in this embodiment to a destination radio | wireless communication apparatus. It is the figure which showed the path | route from the starting point radio | wireless communication apparatus in this embodiment to a destination radio | wireless communication apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Control part, 12 ... Memory | storage part, 13 ... Communication part A, 14 ... Communication part B, 15 ... Communication part C, 801-809 ... Wireless communication apparatus

Claims (2)

In a wireless communication system comprising a wireless communication device provided with a plurality of communication units using different wireless communication methods, a wireless communication route determining device for determining a route for the wireless communication device to perform wireless communication with another wireless communication device Because
The wireless communication status of each of the wireless communication devices included in the wireless communication system, and selected route information that is information indicating whether each wireless communication device is a route that can communicate using each wireless communication method are stored. A storage unit to
A selection unit that sequentially selects the route used by each wireless communication device and the communication method used in the route based on the wireless communication status and the selected route information stored in the storage unit;
A selectable route update unit that updates the selected route information based on the influence of the wireless communication method used in the route selected by the selection unit;
A wireless communication path determination device comprising: Radio communication path determination method for determining a path for the radio communication apparatus to perform radio communication with another radio communication apparatus in a radio communication system including a radio communication apparatus having a plurality of communication units using different radio communication schemes Because
The wireless communication status of each of the wireless communication devices included in the wireless communication system, and selected route information that is information indicating whether each wireless communication device is a route that can communicate using each wireless communication method are stored. A memory step to
A selection step of sequentially selecting the route used by each wireless communication device and the communication method used in the route based on the wireless communication status and the selected route information stored in the storing step;
A selectable route update step for updating the selected route information based on the influence of the wireless communication method used in the route selected in the selection step;
A wireless communication path determining method.

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