JP2008258746A - Communication control apparatus, communication control method, communication control program, node, and communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that delay up to a destination may be generated according to the order of transmission timing of communication data in a network system composed of a plurality of apparatus. <P>SOLUTION: A communication control apparatus for respective nodes composing a communication system includes: a communication timing control means for controlling the communication timing of a node itself by adjusting a communication timing time difference from one or more other nodes; a control signal transmission means for multi-hop transmitting a control signal having communication timing time difference information between the node itself and each of one or more one-hop vicinity node existing in the vicinity of one hop around the node itself; a communication timing time difference information management means for finding out communication timing time difference information between the node itself and each of one or more other nodes existing at least two hops or more ahead of the node itself on the basis of respective control signals received from one or more other nodes; and a data communication means for communicating communication data on the basis of the communication timing time difference information. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a communication control device, a communication control method, a communication control program, a node, and a communication system, for example, a network system including a plurality of devices connected to a sensor network, an ad hoc network, or a LAN (Local Area Network). The present invention can be applied to a communication control system in which a large number of nodes distributed in space perform data communication with each other.

  For example, as a method for avoiding a collision of communication data by allowing individual nodes to mutually adjust time slot allocation in an autonomous and distributed manner without requiring a centralized management server, the techniques described in Patent Literature 1 to Patent Literature 4 There is.

  In each of Patent Documents 1 to 3, a control mechanism for forming a communication timing pattern is shown. In Patent Document 4, each node periodically transmits and receives control signals to and from neighboring nodes. The working form is shown.

  That is, by using the method of Patent Literature 1 to Patent Literature 4, each node periodically transmits a communication timing control signal, recognizes the communication timing relationship with the vicinity, and based on the local communication timing relationship, By controlling the own control signal transmission time, communication timing patterns can be formed in a distributed manner.

  Here, a method of mutually adjusting the transmission timing of other impulse signals as much as possible, a method of designing a communication time to be secured in advance, a method of trying to realize a completely equal communication time, etc. Various communication timing patterns can be formed.

JP 2005-94663 A JP 2006-74617 A JP 2006-74619 A JP 2006-157441 A

  The technologies described in Patent Documents 1 to 4 described above are effective in that the communication timing for avoiding a collision between a plurality of nodes is adjusted autonomously and distributed to ensure a communication band.

  By the way, as a communication timing acquisition method described in the above-mentioned Patent Document 4 and the like, the wireless node does not transmit immediately even if traffic to be transmitted occurs, and queues a packet to be transmitted until the acquired communication timing comes. Later, it is necessary to transmit a transmission packet.

  Such a queuing operation is required not only in the technique described in Patent Document 4, but also in the case of a communication control system that allocates transmission time slots, such as TDMA (Time Division Multiple Access).

  However, the queuing operation as described above has a problem that the time delay until the data packet is delivered to the destination is increased as compared with the communication control system that transmits immediately after the traffic is generated.

  In particular, when performing multi-hop communication, a time delay due to queuing is required for each hop, so that the time delay until reaching the destination is further increased.

  In general, the route selection means of each node determines that a route with a small number of relay nodes has a lower delay, but the communication control method for mutually adjusting the communication timing with other nodes and transmitting the packet is used as it is. When applied, a route with a smaller number of relay nodes does not necessarily have a lower delay depending on the relationship of the transmission order.

  Therefore, there is a need for a communication control device, a communication control method, a communication control program, a node, and a communication system that can select a route that minimizes the time delay until reaching the destination in consideration of the transmission order of communication timing of each node. It has been.

  In order to solve such a problem, a communication control device according to a first aspect of the present invention is a communication control device provided in each of a plurality of nodes constituting a communication system. (1) Between one or a plurality of other nodes Communication timing control means for adjusting the communication timing time difference to control the communication timing of the own node, and (2) communication timing between each of one or a plurality of one-hop neighboring nodes existing in the vicinity of one hop centering on the own node (3) one or a plurality of other nodes existing at least two hops ahead based on each control signal received from one or a plurality of other nodes, and a control signal transmitting means for transmitting a control signal having time difference information in a multi-hop manner Communication timing time difference information management means for obtaining communication timing time difference information between each of the nodes and (4) communication timing Characterized in that it comprises a communication means for communicating the communication data based on the time difference information.

  The node according to the second aspect of the present invention includes the communication control apparatus according to the first aspect of the present invention.

  A communication system according to a third aspect of the present invention includes a plurality of nodes according to the second aspect of the present invention.

  A communication control method according to a fourth aspect of the present invention is a communication control method for a communication control device provided in each of a plurality of nodes constituting a communication system, wherein (1) the communication timing control means is connected to one or more other nodes. A communication timing control step for controlling the communication timing of the own node by adjusting the communication timing time difference between them, and (2) one or a plurality of one-hop neighborhoods in which the control signal transmission means exists in the neighborhood of one hop centering on the own node A control signal transmission step for multi-hop transmission of a control signal having communication timing time difference information between each of the nodes, and (3) communication timing time difference information management means based on each control signal received from one or more other nodes Communication timing time between each of one or more other nodes existing at least two hops away and the own node A communication timing time difference information management step of obtaining the information, (4) communication means, and having a data communication step of communicating the communication data based on the communication timing time difference information.

  A communication control program according to a fifth aspect of the present invention is a communication control program of a communication control device provided in each of a plurality of nodes constituting a communication system, and (1) communicates with one or a plurality of other nodes. A communication timing control means for controlling the communication timing of the own node by adjusting the timing time difference; (2) communication timing time difference information between each of one or a plurality of one-hop neighboring nodes existing in the vicinity of one hop centering on the own node; And (3) each of one or more other nodes existing at least two hops or more based on each control signal received from one or more other nodes. Communication timing time difference information management means for obtaining communication timing time difference information with the own node, (4) communication Communication data based on the timing time difference information is intended to function as a data communication means for communicating.

  According to the communication control device, the communication control method, the communication control program, the node, and the communication system of the present invention, in consideration of the transmission order of the communication timing of each node, the path that minimizes the time delay until reaching the destination is obtained. You can choose.

(A) First Embodiment Hereinafter, a first embodiment of a communication control device, a communication control method, a communication control program, a node, and a communication system of the present invention will be described in detail with reference to the drawings.

  In the first embodiment, in a multi-hop wireless network (also referred to as a communication system) configured with a plurality of nodes, the present invention is used to minimize a data packet delay until reaching a destination. An embodiment for determining the value will be described.

(A-1) Configuration of First Embodiment FIG. 1 is a functional block diagram showing an internal configuration of each node configuring a multi-hop wireless network.

  In FIG. 1, a node 10 according to the first embodiment includes neighboring node information management means 11, control signal transmission management means 12, topology information management means 13, route determination means 14, sensor means 15, application means 16, and data packet transmission. The management means 17 is provided at least.

  The neighboring node information management means 11 receives a control signal 1 sent from another node located in the vicinity of the own node (hereinafter also referred to as a neighboring node), and based on the reception of the control signal 1, the neighboring node information management means 11 Neighboring node information indicating the relationship with the own node is obtained, and this neighboring node information is managed. The control signal 1 is a signal that contributes to transmit the transmission timing of the own node to other nearby nodes.

  Also, the neighboring node information management means 11 newly sets neighboring node information of a newly approaching node, updates neighboring node information, deletes neighboring node information that has become obsolete after a certain period of time, etc. To do.

  Here, the control information 1 has node identification information (for example, a node ID number) of the transmission source node, and the neighboring node information management unit 11 uses the node identification information of the control signal 1 as a basis. Neighboring node information for each neighboring node is managed.

  The neighboring node information managed by the neighboring node information management means 11 includes, for example, node identification information of neighboring nodes, a time difference (hereinafter also referred to as a phase difference) of communication timings of the nodes, and a one-hop neighborhood centered on the own node. Signal reception intensity of a signal received from a neighboring node located at

  As a method for calculating a time difference (phase difference) between communication timings of nodes, a communication timing calculation method described in any of Patent Documents 1 to 4 and the like can be widely applied.

  Also, the neighboring node information management unit 11 gives neighboring node information of the managed neighboring node to the control signal transmission management unit 12.

  The control signal transmission management unit 12 receives the neighboring node information from the neighboring node information management unit 11 and sends out a control signal generated based on the neighboring node information at every predetermined time interval.

  Here, there are two types of control signals transmitted by the control signal transmission management means 12. The first control signal has at least node identification information of the own node in order to cause other nodes located in the vicinity to recognize the existence of the own node, and is indicated as a control signal 1.

  Further, the second control signal has at least the node identification information of the own node and the own node to recognize the phase difference between the own node and other nodes located in the vicinity of the second control signal over a wide range of the wireless network. It has node identification information of other nodes located in the vicinity of 1 hop as a center, and has a phase difference between the own node and each 1 hop neighborhood node, and is indicated as a control signal 2.

  Note that the information included in the control signal 2 is not limited to the above information, and may include, for example, the signal reception strength of the signal received by the own node from the 1-hop neighboring node.

  Further, a method for transferring the control signal 2 as the second control signal over a wide range of the wireless network can be realized by flooding, for example. The flooding range can be managed by setting the lifetime of the control signal 2 in TTL (Time To Live) described in the packet header information of the control signal 2.

  The topology information management means 13 receives the control signal 2 sent by the neighboring node, and based on the packet header information of the received control signal 2 and the neighboring node information managed by the neighboring node information management means 11, a wide range in the wireless network The node time difference information 13a is created and the topology information 13a is managed.

  Here, FIG. 2 is an explanatory diagram showing an example of the inter-node time difference information 13a managed by the topology information management means 13. 2 shows the inter-node time difference information 13a created by the topology information management means 13 of the node A in the network topology arrangement illustrated in FIG.

  For example, it is assumed that the topology information management means 13 of the node A receives the control signal 2 from the neighboring node B.

The control signal 2 of the neighboring node B includes “node identification information of the neighboring node B”, “node identification information of the node A”, “node identification information of the node F”, and “node identification information of the one-hop neighboring node” Node identification information of D ”,“ Phase difference d _ab with node A ”,“ Phase difference d _fb with node F ”, and“ Phase difference d _db with node D ”are included as phase differences with neighboring nodes of 1 hop. It is.

Furthermore, the information “phase difference d _ba ” and “phase difference d _bd ” included in the control signal 2 received from another node (for example, the node D and the node F) located one hop ahead of the node A as the center. And using the “phase difference d _bf ”, the topology information management unit 13 generates topology information related to the node B as shown in FIG. Similarly, the topology information management unit 13 also generates topology information related to the neighboring node C.

  As described above, when the topology information management unit 13 generates the inter-node time difference information 13a based on the information included in the control signal 2, the network topology as shown in FIG. Can be recognized.

  The route determination unit 14 determines a route that minimizes the delay to the destination node of the data packet based on the inter-node time difference information 13a managed by the topology information management unit 13, and transfers based on the route that minimizes the delay. The destination node (hereinafter also referred to as the next node) is given to the data packet transmission management means 17.

  Here, the route determination means 14 creates a delay information management table 14a based on the inter-node time difference information 13a based on the destination node of the data packet, and refers to the delay information management table 14a to The route that minimizes the total phase difference between the nodes in the route to the destination node is determined as the route that minimizes the delay.

  FIG. 6 is an explanatory diagram showing a configuration example of the delay information management table 14a. The delay information management table 14a is configured by associating the destination of the data packet, the next node, and the delay information (the total value of the phase differences between the nodes in the route) for each route from the own node to the destination node. Is done.

  The data packet transmission management unit 17 performs multi-hop wireless transmission of a data packet received from the sensor unit 15 or the application unit 16 or a relay data packet received from another node, for example, toward the next transfer destination node. The data packet transmission management unit 17 extracts the destination node from the packet header of the data packet, inquires the route determination unit 14 about the next node, and then transmits it to the next node determined by the route determination unit 14.

  Further, the data packet transmission management means 17 sets the period from the transmission timing of the control signal 1 of the own node to the reception of the control signal 1 from the other node immediately after that as the transmission timing of the data packet.

(A-2) Operation of the First Embodiment Next, the operation of the communication path calculation process in each node constituting the multi-hop wireless network of the first embodiment will be described with reference to the drawings.

  Hereinafter, as illustrated in FIG. 3, a network in which the nodes A to F are arranged will be described as an example.

  In the initial state, each node does not hold neighboring node information. In each of the nodes A to F, the control signal transmission management means 12 generates a control signal 1 including at least the node identification information of the own node, and transmits the control signal 1. Each node is pre-assigned with node identification information of its own node.

  The control signal 1 transmitted from each of the nodes A to F is received by another node existing in the vicinity of one hop of each of the nodes A to F. When the control signal 1 is received by the node, the neighboring node information management unit 11 recognizes the transmission source node of the control signal 1 as a neighboring node based on the node identification information included in the control signal 1.

  The neighboring node information management means 11 calculates a time difference between the transmission timing of the control signal 1 of the own node and the reception timing of the control signal 1 of the neighboring node (in this case, the transmission source node of the control signal 1). A time difference is calculated as a phase difference. Of course, when there are a plurality of neighboring nodes, the phase difference is similarly calculated for each of the plurality of neighboring nodes.

  In this way, the neighboring node information obtained by the neighboring node information management unit 11 is managed by the neighboring node information management unit 11.

  Then, since the neighboring node information is held in each of the nodes A to F, the control signal transmission management unit 12 at least determines the node identification information of the own node and the node identification information of the one-hop neighboring node based on the neighboring node information. 1 generates a control signal 2 including a phase difference with a hip neighboring node, and sends the control signal 2 at a predetermined time interval.

  The control signal 2 is transmitted over a wide area of the wireless network. At this time, for example, the lifetime of the control signal 2 is set using TTL included in the packet header information of the control signal. Thereby, it is possible to transmit over a wide range of the wireless network by being multi-hopped between the nodes for the lifetime set by TTL.

  When the control signal 2 is received by each of the nodes A to F, the topology information management unit 13 of each of the nodes A to F includes the node identification information of the transmission source node included in the control signal 2 and the one-hop neighboring node. Node identification information and a phase difference with a 1-hop neighboring node are extracted.

  Then, the topology information management means 13 creates the inter-node time difference information 13a based on the node identification information of the transmission source node, the node identification information of the one-hop neighboring node, and the phase difference from the one-hop neighboring node. To do.

  Here, the process of creating the inter-node time difference information 13a by the topology information management means 13 will be described with reference to FIGS.

  FIG. 4 is an explanatory diagram illustrating a transmission timing relationship with a node existing in the vicinity of two hops centering on the node A when the network topology illustrated in FIG. 3 is configured, for example.

  In FIG. 4, a circle 41 indicates one cycle period in which transmission timings are assigned to each other between the nodes A to nodes. The notations “A” to “F” shown on the circle 41 in FIG. 4 indicate the transmission timing of the control signal 1 in the nodes A to F. For example, the communication timing of the data packet of the node A corresponds to the period from the transmission timing of the control signal 1 of the node A to the reception timing of the control signal 1 from the other node (node B in this case) that arrives thereafter. To do.

  Also, in FIG. 4, the transmission timing of the data packets comes in order of node A, node B, node D, node F, node E, and node C within one cycle, and this transmission order is made periodically. The phase differences dca, dab, dbd, dcf, dfb correspond to the arrows in FIG.

  As described above, by flooding the control signal 2 over the entire wireless network, it is possible to recognize the communication timing with other nodes existing up to two hops around each node, It is possible to obtain a phase difference relationship with the own node.

That is, for example, node A has node B and node C in the vicinity of one hop, node B → node A and node C → node A are connected, phase difference d _ba with node B, node The control signal 2 including the phase difference _dca with C is flooded to the wireless network.

Node B has node A, node D and node F in the vicinity of one hop, node A → node B and node D → node B and node F → node B, The control signal 2 including the phase difference d _ab , the phase difference d _db with the node D, and the phase difference d _fb with the node F is flooded.

  Further, the node F, the node D, and the like flood the control signal 2 having the same contents.

  When the control signal 2 is sufficiently exchanged between the nodes after a certain period of time in the wireless network, the topology information management means 13 of each node will connect each node of the entire network and each node as network topology information. The phase difference between them can be referred to.

  As a result, the node A has a topology as shown in FIG. 2 based on the control signal 2 from the nodes B and C in the vicinity of 1 hop and the control signal 2 from the nodes F and D in the vicinity of 2 hops. Information can be created.

  Thereafter, when transmitting sensor data, application data, or the like, the data packet transmission management unit 17 inquires the route determination unit 14 about the transfer destination of the data packet.

  When an inquiry about the transfer destination is made from the data packet transmission management unit 17, the route determination unit 14 of each of the nodes A to F performs the route determination process shown in FIG. 5, and the data packet transmission management unit determines the next node according to the determined route. 17 is notified.

  That is, in FIG. 5, when the destination of the data packet is given from the data packet transmission management unit 17 to the route determination unit 14 (step S101), the route determination unit 14 refers to the topology information (step S102), and the data packet One or a plurality of routes to the destination is determined (step S103).

  Then, the route determination unit 14 calculates the total value of the phase differences between the nodes up to the destination for each of one or a plurality of routes with reference to the inter-node time difference information 13a (step S104).

  The route determination means uses the total value of the phase differences between the nodes of each route as the route delay of each route, and selects the route with the smallest route delay from each route (step S105). Based on this, the next node is determined (step S106), and the next node is notified to the data packet transmission management means 17 (step S107).

  For example, in FIG. 3, a case where the node C generates a data packet such as sensor data or application data and transmits the data packet to the node D will be described as an example.

  In this case, the route determination unit 14 of the node C has a route “node C → node F → node B → node D” (hereinafter referred to as a first route) and a route “from the node C to the node D”. Node C → Node A → Node B → Node D ”(hereinafter referred to as the second route).

Then, the path determination unit 14 refers to the inter-node time difference information 13a, and the total value “d _cf + d _fb + d _bd ” (hereinafter referred to as the first path delay) between the nodes constituting the first path. ) Similarly, a total value “d _ca + d _ab + d _bd ” (hereinafter referred to as a second path delay) of the phase differences between the nodes constituting the second path is obtained. FIG. 6 is a delay information management table 14a showing an example of delay information provided in the node C, and shows the relationship between the delay information up to the destination and the next node for each route up to the destination centering on the node C. is there.

  The route determination means 14 compares the first route delay with the second route delay and selects a route having a small route delay (for example, in this case, when the second route delay is smaller than the first route delay). , Select the second route).

  Then, the route determination unit 14 notifies the data packet transmission management unit 17 of the next transfer destination node, Node A, as the next node from the second route. FIG. 6 is a management table showing an example of delay information provided in the node C, and shows the relationship between the delay information up to the destination and the next node for each route to the destination with the node C as the center.

  As a result, the data packet origin management means 17 performs multi-hop wireless transmission with the transfer destination of the data packet to be transmitted as the node A.

  The route determination process described above is also performed on data packets to be relayed and transferred at each node. Then, the data packet is transferred to the node D that is the final destination.

(A-3) Effects of the First Embodiment As described above, according to the first embodiment, the number of relays is small in the conventional method so that the delay is reduced when determining a multihop communication route. Even if a route is selected, the delay time to reach the destination may actually be longer than other routes due to the influence of queuing time. The transmission timing schedule between the nodes of the link when the mutual transmission timing schedule is exchanged by exchanging the control signal 2 to obtain the transmission timing time difference between the nodes and flooding the connection state of the link as topology information. By transmitting the time difference information at the same time, it is possible to select a route with a small delay based on the transmission timing time difference information between the nodes.

  As a result, even in the method of managing the transmission timing, it is possible to appropriately select a path for shortening the queuing time and reduce the delay.

(B) Other Embodiments (B-1) In the first embodiment, the control signal 2 is at least the node identification information of its own node, and the node identification information of another node located in the vicinity of one hop with each node as a center. The case of having a phase difference between the own node and each 1-hop neighboring node has been described. However, in addition to this, signal strength information (reception power value) of a signal received from a 1-hop neighboring node may be added.

  Thereby, for example, in order for each node to optimally form the phase relationship (transmission timing relationship) between the nodes, the distance between the nodes is calculated based on the received power value, and the phase is determined based on the distance. Even when a determination function for determining whether or not a node is to form a relationship is provided, the same effect as in the first embodiment can be obtained.

(B-2) The configuration of the control signal transmission management unit 12 described in the first embodiment is not limited to the configuration shown in FIG.

  For example, in FIG. 1, both the control signal 1 and the control signal 2 are transmitted by the control signal transmission management unit 12, but each control signal 1 or control signal may be transmitted in a different configuration.

  Further, for example, a functional unit having both the function of the topology information management unit 13 and the function of the neighboring node information management unit 11 may be used.

(B-3) In the first embodiment, as an example of the network topology, the case of obtaining topology information up to two hops away is taken as an example. However, three or more hops may be used.

(B-4) Communication timing control process using control signal 1 As described above, each node in the first embodiment calculates a communication timing by exchanging control signal 1 between the nodes. .

  Therefore, hereinafter, communication timing control processing using the control signal 1 in each node will be described with reference to the drawings.

  FIG. 7 is a functional block diagram showing a functional configuration for performing communication timing control using the control signal 1 in each node.

  As shown in FIG. 7, the node 10 includes an impulse signal reception unit 21, a communication timing calculation unit 22, an impulse signal transmission unit 23, a tuning determination unit 24, a data packet transmission management unit 17, and a sensor unit 15.

  In the following description, the control signal 1 is described as an impulse signal.

  The neighbor node information management unit 11 in FIG. 1 has a function as the impulse signal reception unit 21 in FIG. 7 for the communication timing control process using the control signal 1.

  The control signal transmission management unit 12 in FIG. 1 has functions as the communication timing calculation unit 22, the impulse signal transmission unit 23, and the tuning determination unit 24 in FIG. 7 for the communication timing control process using the control signal 1.

  The impulse signal receiving means 21 receives an output impulse signal transmitted from a nearby node (for example, another node existing in a range where a transmission radio wave of the node reaches) as an input impulse signal Sin11. Here, the impulse signal is transmitted and received as a timing signal, and has an impulse shape such as a Gaussian distribution shape, for example. The reception impulse signal Spr11 may be a waveform-shaped signal of the input impulse signal Sin11 or a signal regenerated.

  The communication timing calculation means 22 forms and outputs a phase signal Spr12 that defines the communication timing at the node based on the received impulse signal. Note that the communication timing calculation means 22 forms and outputs the phase signal Spr12 even when there is no received impulse signal Spr11.

Here, assuming that the phase value at time t of the phase signal Spr12 of the node i is θi (t), the communication timing calculation unit 22 may, for example, formulas (1) and (2) below based on the received impulse signal Spr11. As described above, the phase signal Spr12 (= θi (t)) is changed with a nonlinear vibration rhythm.

  This change in phase signal is a result of realizing a non-linear characteristic in which neighboring nodes are opposite in phase (vibration phase is inverted) or other phase, and trying to avoid collision using that characteristic. It is. That is, an appropriate time relationship (time difference) is formed so that the transmission timing of the output impulse signal Sout11 between neighboring nodes does not collide.

  In the following, the components constituting the above formulas (1) and (2) will be briefly described. The above equation (1) is an equation indicating a rule (temporal evolution rule) for temporally changing the nonlinear vibration rhythm of its own node (referred to as node i). In the above equation (1), the variable t represents time, and the function θi represents the phase with respect to the nonlinear vibration of the node at time t.

  In the above equation (2), Δθij (t) is a phase difference obtained by subtracting the phase θi (t) of its own node i from the phase θj (t) of the neighboring node j.

  Further, ωi is a natural angular frequency parameter. The function Pj (t) represents the received impulse signal Spr11 received from the neighboring node j, and the function R (Δθij (t)) corresponds to the basic rhythm of the own node i according to the input of the received impulse signal Spr11. N represents the total number of neighboring nodes existing in the spatial distance range in which the node can receive the received impulse signal Spr11.

  The function ξ (Si (t)) accumulates stress when the relative phase difference between the node i and the neighboring node j is small, and the function ξ (Si (t)) has a random magnitude according to the accumulated stress value Si (t). It is a term that works to phase shift.

  8 and 9 are explanatory diagrams for explaining the meaning of the function of the communication timing calculation means 22. The state changes shown in FIGS. 8 and 9 are also related to the function of the impulse signal transmission means 23.

  8 and 9 show a relationship formed between a target node (own node) and a neighboring node (another node) when attention is paid to a certain node, that is, a phase relationship between respective nonlinear vibration rhythms. Shows how the changes over time.

  FIG. 8 shows a case where there is one neighboring node j for the node of interest i. In FIG. 8, the motion of the two mass points rotating on the circle represents the nonlinear vibration rhythm corresponding to the node of interest and the neighboring nodes, and the angle of the mass point on the circle represents the value of the phase signal at that time. Yes. The motion of the point where the rotational motion of the mass point is projected on the vertical or horizontal axis corresponds to the nonlinear vibration rhythm. By the operation based on the expression (1) described later, the two mass points try to be in opposite phases to each other, and even if the phases of the two mass points are close to each other in the initial state as shown in FIG. At the same time, the state (transient state) shown in FIG. 8B is changed to a steady state in which the phase difference between the two mass points is almost π as shown in FIG. 8C.

  Each of the two mass points rotates with the natural angular frequency parameter ω as a basic angular velocity (corresponding to a basic velocity that changes its own operation state). Here, when an interaction based on transmission / reception of an impulse signal occurs between nodes, these mass points change (slow / slow) angular velocities, respectively, and eventually reach a steady state in which an appropriate phase relationship is maintained. This operation can be regarded as forming a stable phase relationship by repelling each other while the two mass points rotate. In the steady state, as will be described later, when the output impulse signal Sout11 is transmitted when each node is in a predetermined phase (for example, 0), the transmission timings at the nodes form an appropriate time relationship. It will be.

  FIG. 9 shows a case where there are two neighboring nodes j1 and j2 for the node of interest i. Even when there are two neighboring nodes, a stable phase relationship (stability with respect to temporal relationship) is formed by repelling each other while rotating the respective mass points, as described above. The same applies to the case where the number of neighboring nodes is three or more.

  The formation of the above-described stable phase relationship (steady state) has a very adaptive (flexible) property with respect to changes in the number of neighboring nodes. For example, it is assumed that one neighboring node is added when there is one neighboring node with respect to the node of interest and a stable phase relationship (steady state) is formed. The steady state once collapses, but after passing through the transient state, a new steady state in the case where there are two neighboring nodes is reformed. In addition, when a neighboring node is deleted or does not function due to a failure or the like, an adaptive operation is performed in the same manner.

  The communication timing calculation unit 22 outputs the obtained phase signal Spr12 (= θi (t)) to the impulse signal transmission unit 23, the tuning determination unit 24, and the data packet transmission management unit 17.

  The impulse signal transmission unit 23 transmits the output impulse signal Sout11 based on the phase signal Spr12. That is, when the phase signal Spr12 reaches a predetermined phase α (0 ≦ α <2π), the output impulse signal Sout11 is transmitted. Here, it is preferable that the predetermined phase α is previously unified in the entire system. In the following description, it is assumed that α = 0 is unified throughout the system. In the example of FIG. 8, since the mutual phase signal Spr12 is shifted by π in the steady state between the node i and the node j, even if the system is unified to α = 0, The transmission timing of the output impulse signal Sout11 and the transmission timing of the output impulse signal Sout11 from the node j are shifted by π.

  The tuning determination means 24 is a “transient state” (see FIG. 8B and FIG. 9B) for mutual adjustment of the transmission timing of the output impulse signal Sout11 performed between the own node and one or a plurality of neighboring nodes. Alternatively, it is determined which state is the “steady state” (see FIG. 8C and FIG. 9C). The tuning determination unit 24 observes the generation timing of the reception impulse signal Spr11 (corresponding to the output impulse signal Sout11 of the other node) and the output impulse signal Sout11, and the time difference between the generation timings of a plurality of nodes that exchange the impulse signals. When it is stable over time, it is determined that the state is “steady state”. In the case of this embodiment, the tuning determination means 24 receives the phase signal Spr12 instead of the output impulse signal Sout11 as a signal for capturing the generation timing of the output impulse signal Sout11 from the own node. Yes.

  The tuning determination unit 24 performs tuning determination by executing the following processes (a) to (d), for example.

  (A) The value β of the phase signal Spr12 at the generation timing of the reception impulse signal Spr11 is observed over one period of the phase signal Spr12. Here, the values β of the phase signal Spr12 obtained as a result of the above observation are set to β1, β2,..., ΒN (0 <β1 <β2 <... ΒN <2π), respectively.

  (B) Based on the observed value β of the phase signal Spr12, the difference (phase difference) between adjacent values Δ1 = β1, Δ2 = β2-β1,..., ΔN = βN−β (N−1) Is calculated.

  (C) The above processes (a) and (b) are performed in units of the period of the phase signal Spr12, and the amount of change (difference) in the phase difference Δ in successive periods γ1 = Δ1 (τ + 1) −Δ1 ( τ), γ2 = Δ2 (τ + 1) −Δ2 (τ),..., γN = ΔN (τ + 1) −ΔN (τ) are calculated. Here, τ indicates a certain cycle of the phase signal Spr12, and τ + 1 indicates the next cycle of the phase signal Spr12.

  (D) When the above-mentioned change amount γ is smaller than the minute parameter (threshold value) ε, that is, when γ1 <ε, γ2 <ε,. To do.

  Note that a steady state may be determined when the conditions of γ1 <ε, γ2 <ε,..., ΓN <ε are satisfied over M cycles. As the value of M is increased, it is possible to determine “steady state” in a more stable state. Further, the “steady state” may be determined based on a part of the received impulse signal Spr11.

  The tuning determination means 24 transmits a data packet as a slot signal Spr14 with a tuning determination signal Spr13 indicating a determination result and a minimum value β1 of the value β of the phase signal Spr12 at the generation timing of the reception impulse signal Spr11 for each period of the phase signal Spr12. Output to the management means 17.

  Note that the output of the minimum value β1 as the slot signal Spr14 is related to α = 0 as described above, and β applied to the slot signal Spr14 depends on the selection of the value of α. The value of varies.

  The node 10 has a function of relaying and transmitting data received from other nodes, and a data transmission function using itself as a transmission source.

  The sensor means 15 is written as an example of the latter case. For example, the sensor means 15 detects physical or chemical environment information Sin13 such as the intensity of sound and vibration, the concentration of chemical substances, and the temperature, and the observation data Spr15 is obtained. This is output to the data packet transmission management means 17.

  In the former case, the data packet transmission management means 17 receives the data signal (output data signal Sout12) transmitted by the neighboring node as the input data signal Sin12.

  The data packet transmission management means 17 transmits the observation data Spr15 and / or the input data signal Sin12 (including both cases) as an output data signal Sout12 to another node. The data packet transmission management means 17 refers to this transmission when the tuning determination signal Spr13 indicates “steady state”. When the tuning determination signal Spr13 indicates “transient state”, the transmission operation is stopped. Note that the output data signal Sout12 may have a transmission frequency in the same frequency band as the output impulse signal Sout11.

  The time slot is a period in which the phase θi (t) of the phase signal Spr12 is δ1 ≦ θi (t) ≦ β1-δ2. The start point of the time slot (the value of the phase signal at that time is δ1) is the timing at which the transmission of the output impulse signal Sout11 is completed, and the end point of the time slot (the value of the phase signal at that time is β1-δ2). ) Is a timing that is slightly offset δ2 before the timing of the first reception impulse signal Spr11 for each period of the phase signal Spr12. δ1 and δ2 are an impulse signal (including both the case where the transmission source is the own node and the case of the other node) and the data signal (when the transmission source is the own node, the other node) in the wireless space near the node 10 Phase width corresponding to a very short time to compensate for the absence of both at the same time. For example, δ1 and δ2 are experimentally determined under the installation state of the node 10.

  For example, in the “steady state” as shown in FIG. 8C, the node i starts transmitting the output impulse signal Sout11 from the phase θi of 0, and before the phase θi becomes δ1, the node i of the output impulse signal Sout11 The transmission is terminated, the phase θi starts to transmit the output data signal Sout12 from δ1, and when the phase θi becomes β1−δ2 (where β1≈π), the transmission of the output data signal Sout12 is terminated. Until θi becomes 0 again, transmission of the output impulse signal Sout11 and transmission of the output data signal Sout12 are stopped. The other node j also performs the same operation based on the phase θj. However, since the phase θi and the phase θj are substantially shifted by π, the transmission operation does not compete. The same operation is performed when the number of nodes is 3 or more, and transmission operations do not compete.

(B-5) The calculation method of the communication timing using the control signal 1 mentioned above is not limited to the said method, The method described in patent documents 1-4 can be applied widely.

(B-6) In the first embodiment, a description has been given assuming a system in which a large number of nodes distributed in space exchange data with each other wirelessly. However, the usage form of the present invention is not limited to a system that performs wireless communication. It can also be applied to a system in which a large number of nodes distributed in space exchange data with each other by wire. For example, the present invention can be applied to a LAN system connected by wire such as Ethernet (registered trademark). Similarly, the present invention can be applied to a network in which different types of nodes are mixed, such as sensors, actuators, and servers connected in a wired manner. Of course, the present invention can be applied to a network in which nodes connected by wire and nodes connected wirelessly are mixed.

  In addition, the present invention is applicable to the problem of collision and synchronization of outgoing data existing in any network regardless of wireless system or wired system, and communication that realizes efficient data communication having both adaptability and stability. It can be used as a protocol.

(B-7) The node of the present invention can be realized by software processing realized by a hardware resource (for example, CPU) executing a program. That is, various functional configurations included in the node are stored as programs. Note that various processes of the node may be realized by hardware.

It is a functional block diagram which shows the internal structure of the node of 1st Embodiment. It is explanatory drawing which shows the example of the topology information of 1st Embodiment. It is a figure which shows the example of node arrangement | positioning of 1st Embodiment, and network topology information. It is explanatory drawing which shows the relationship of the transmission timing of each node at the time of centering on the node A of 1st Embodiment. It is an operation | movement flowchart of the route determination process of 1st Embodiment. It is explanatory drawing which shows the delay information of each path | route in the node C of 1st Embodiment. It is a functional block diagram which shows the function structure of the communication timing control of the node using the control signal 1. FIG. It is explanatory drawing (1) explaining the tuning between nodes in a communication system. It is explanatory drawing (2) explaining the tuning between nodes in a communication system.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Node, 11 ... Neighboring node information management means, 12 ... Control signal transmission management means, 13 ... Topology information management means, 13a ... Inter-node time difference information, 14 ... Path determination means, 15 ... Sensor means, 16 ... Application means 17 Data packet transmission management means.

Claims (10)

In a communication control device provided in each of a plurality of nodes constituting a communication system,
Communication timing control means for adjusting the communication timing time difference with one or more other nodes to control the communication timing of the own node;
Control signal transmission means for multi-hop transmitting a control signal having communication timing time difference information between each of one or a plurality of one-hop neighboring nodes existing in the vicinity of one hop centering on the own node;
Communication timing time difference information for obtaining communication timing time difference information between each of one or a plurality of other nodes existing at least two hops ahead and the own node based on each control signal received from one or a plurality of other nodes Management means;
A communication control apparatus comprising: data communication means for communicating communication data based on the communication timing time difference information.   The control signal includes at least node identification information of the own node, node identification information of each of the one-hop neighboring nodes, and communication timing time difference information between each of the one-hop neighboring nodes and the own node. The communication control device according to claim 1.   The communication timing time difference information management means includes a network topology information creation unit that creates network topology information in which the communication timing time difference information between the nodes is associated with each other based on information included in each control signal. The communication control apparatus according to claim 1 or 2, characterized by the above.   Based on the network topology information, the communication timing time difference information management means obtains a total value of the communication timing time difference information between the nodes for each of one or a plurality of paths for transfer to the destination of the communication data. The communication control device according to claim 3, further comprising: a route determination unit that determines a transfer route of the communication data based on a total value of the communication timing time difference information for each of the routes.   5. The communication control apparatus according to claim 4, wherein the route determination unit determines a route having a minimum total value of the communication timing time difference information as a transfer route of the communication data.   The communication timing control means determines the transmission timing of the timing signal of the node using the reception timing of the timing signal from the other node, and based on the transmission timing and the reception timing of the timing signal from the other node, 6. The communication control apparatus according to claim 1, further comprising a timing calculation unit that determines a transmission time slot of the data signal.   A node comprising the communication control device according to claim 1.   A communication system comprising a plurality of nodes according to claim 7. In a communication control method of a communication control device provided in each of a plurality of nodes constituting a communication system,
A communication timing control step in which the communication timing control means adjusts the communication timing time difference with one or more other nodes to control the communication timing of the own node;
A control signal transmitting step for causing the control signal transmitting means to multi-hop transmit a control signal having communication timing time difference information between each of one or a plurality of 1-hop neighboring nodes existing in the vicinity of one hop centering on the own node;
Based on the control signals received from the one or more other nodes by the communication timing time difference information management means, the communication timing between each of the one or more other nodes existing at least two hops ahead and the own node Communication timing time difference information management process for obtaining time difference information;
And a data communication step in which the data communication means communicates the communication data based on the communication timing time difference information. In a communication control program of a communication control device provided in each of a plurality of nodes constituting a communication system,
On the computer,
Communication timing control means for controlling the communication timing of the own node by adjusting the communication timing time difference with one or a plurality of other nodes;
Control signal transmission means for multi-hop transmission of a control signal having communication timing time difference information between each of one or a plurality of 1-hop neighboring nodes existing in the vicinity of one hop centering on the own node;
Communication timing time difference information for obtaining communication timing time difference information between each of one or a plurality of other nodes existing at least two hops ahead and the own node based on each control signal received from one or a plurality of other nodes Management means,
A communication control program for functioning as data communication means for communicating communication data based on the communication timing time difference information.

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