JP4301283B2 - Communication timing control device, communication timing control method, communication timing control program, node, and communication system - Google Patents

Description

  The present invention relates to a communication timing control device, a communication timing control method, a communication timing control program, a node, and a communication system. For example, a large number of nodes and mobile units distributed in a space such as a sensor network perform data communication with each other. When performing, it can be applied to a method of autonomously assigning an appropriate communication time, forming a communication timing, and performing communication efficiently.

  Patent Documents 1 to 4 do not require a centralized management server, and a plurality of spatially distributed nodes each assign a time slot by mutual adjustment with neighboring nodes, and communication timing of communication data Describes a technology related to communication timing control that autonomously forms data and realizes data communication without collision.

  That is, each node periodically sends and receives timing control signals to and from neighboring nodes, recognizes the communication timing relationship with neighboring nodes, and determines its own timing control signal based on the local communication timing relationship. By controlling the transmission time (transmission timing), the communication timing pattern is formed in an autonomous and distributed manner.

  Here, the communication timing pattern can be formed by, for example, mutually adjusting the transmission timings of other timing control signals at each node as much as possible, and ensuring communication time in advance during one cycle of operation. Various patterns have been proposed, such as a method for setting to do so and a method for achieving completely equal communication time.

Japanese Patent Laying-Open No. 2005-094663 JP 2006-074617 A JP 2006-0774619 A JP 2006-157441 A

  As described above, the communication timing control methods described in Patent Literature 1 to Patent Literature 4 include a method of adjusting the transmission timing of the other timing control signal as far as possible, and the communication time during one cycle of operation. A method of setting to ensure in advance is disclosed.

  The communication timing control methods described in Patent Literature 1 to Patent Literature 4 are effective in that each node can autonomously decentralize communication data communication timing and secure a bandwidth. Thereby, in order for each node to communicate correctly, it is possible to secure a sufficiently long communication time, or to set a communication time assuming traffic that may occur from now on.

  However, in the conventional communication timing control method, when the network topology, the traffic pattern, and the like are dynamically changed, it is difficult to dynamically correspond to the communication time according to the change.

  Further, in order to realize this type of communication network (communication system), it is required to improve the utilization efficiency of the network, ease of prior design regarding communication timing control of each node, reduction of management cost, and the like.

  Therefore, even when the network topology, traffic pattern, etc. dynamically change, a communication timing control device that realizes the formation of a communication timing pattern that can form a communication timing pattern corresponding to the change in each node, There is a need for a communication timing control method, a communication timing control program, a node, and a communication system.

  In order to solve this problem, a communication timing control device according to the first aspect of the present invention is a communication timing control device provided in a node constituting a communication system, and uses communication timings of timing control signals from other nodes. Communication timing control for determining the communication timing of the timing control signal of the own node, and determining the transmission period of the data signal based on the communication timing of the timing control signal of the own node and the communication timing of the timing control signal of the other node In the apparatus, (1) timing control signal transmission / reception means for transmitting / receiving the timing control signal to / from another node, (2) a required transmission period necessary for transmitting a data signal of the own node, and a data signal of the other node Based on the required transmission period required for transmission of (3) a phase response function adjusting means for adjusting a phase response function for determining a signal communication timing relationship; and (3) using the phase response function adjusted by the phase response function adjusting means, according to a predetermined time evolution rule, Communication timing calculation means for calculating the communication timing of the timing control signal.

  A communication timing control method according to a second aspect of the present invention is a communication timing control method provided in a node constituting a communication system, and uses the communication timing of a timing control signal from another node, and the timing control signal of the own node In the communication timing control method for determining the transmission timing of the data signal based on the communication timing of the timing control signal of the own node and the communication timing of the timing control signal of the other node, (1) the timing control signal A timing control signal transmission / reception step in which the transmission / reception means transmits / receives the timing control signal to / from another node; and (2) a required transmission period necessary for the phase response function adjustment means to transmit the data signal of the own node; Based on the required transmission period required for transmission of data signals of other nodes, A phase response function adjusting means for adjusting a phase response function for determining a communication timing relationship of timing control signals of other nodes; and (3) a communication timing calculating means using the phase response function adjusted by the phase response function adjusting means. And a communication timing calculating means for calculating the communication timing of the timing control signal of the own node according to a predetermined time development rule.

  A communication timing control program according to a third aspect of the present invention is a communication timing control program provided in a node constituting a communication system, and uses a communication timing of a timing control signal from another node, and the timing control signal of the own node In the communication timing control program for determining the transmission timing of the data signal based on the communication timing of the timing control signal of the own node and the communication timing of the timing control signal of the other node, Timing control signal transmitting / receiving means for transmitting / receiving the timing control signal to / from another node, (2) a required transmission period necessary for transmitting the data signal of the own node, and a necessary requirement for transmitting the data signal of the other node Based on the transmission period, the timing of the own node and other nodes A phase response function adjusting means for adjusting a phase response function for determining the communication timing relationship of the control signal, and (3) the own node according to a predetermined time evolution rule using the phase response function adjusted by the phase response function adjusting means It functions as a communication timing calculation means for calculating the communication timing of the timing control signal.

  A node according to a fourth aspect of the present invention is characterized in that a node constituting the communication system includes the communication timing control apparatus according to the first aspect of the present invention.

  A communication system according to a fifth aspect of the present invention includes a plurality of nodes according to the fourth aspect of the present invention.

  According to the present invention, even when the network topology, traffic pattern, and the like change dynamically, a communication timing pattern corresponding to the change can be formed at each node.

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

  The first embodiment uses a communication timing control device, a communication timing control method, a communication timing control program, a node, and a communication system of the present invention in a wireless communication network (communication system) configured with a plurality of nodes. An embodiment in which each node calculates communication timing based on its own timing control signal will be described.

  In the first embodiment, a wireless communication network used in a sensor network will be described as an example.

(A-1) Configuration of First Embodiment (A-1-1) Configuration of Radio Communication Network FIG. 2 is an overall configuration diagram of the radio communication network (sensor network) NT of the first embodiment. In FIG. 2, the wireless communication network NT according to the first embodiment includes a large number of nodes A and sink nodes S.

  Each of the large number of nodes A is provided with a sensor in advance, and periodically or constantly observes observation data, and wirelessly transmits a communication packet including the observation data during the communication time of the own node (hereinafter referred to as “node”). Neighboring node; give to other nodes that are within the reach of the node. Also, the neighboring node that has received the communication packet wirelessly transmits the communication packet including the received observation data and the observation data of the own node during the communication time of the own node. This transfer is repeated, and observation data finally reaches the sink node S.

  The sink node S is a node as a final destination of the sensor data of each node A. The function of the sink node S basically has a configuration that each node A described below has. In addition, the sink node S may be connected (wired connection or wireless connection) or mounted with a processing device that performs predetermined processing.

(A-1-2) Internal Configuration of Node FIG. 3 is an internal configuration diagram showing the internal configuration of each node A. In FIG. 3, each node A includes at least a communication timing calculation unit 1, a timing control signal reception unit 2, a timing control signal transmission unit 3, a tuning determination unit 4, a data communication unit 5, and a sensor 6. .

  The communication timing calculation means 1 calculates the communication timing of the data signal of the own node using the timing control signal received from the timing control signal receiving means 2 and the transmission timing of the control signal of the own node.

  Although details of a communication timing calculation method in the communication timing calculation means 1 will be described later, basically, a timing control signal is transmitted to and from neighboring nodes using the mechanisms described in Patent Documents 1 to 4, etc. Controls the transmission timing of the timing control signal of its own node based on the communication timing relationship between its own node and neighboring nodes while controlling so that the transmission timing of the node does not collide, and forms a communication timing pattern in an autonomous and distributed manner is there.

  Further, the communication timing calculation unit 1 forms a phase signal that defines the communication timing in the own node, and provides the phase signal (phase information) to the timing control signal transmission unit 3, the tuning determination unit 4, and the data communication unit 5. Is.

  The timing control signal receiving means 2 receives a timing control signal sent from a neighboring node, and gives the received timing control signal to the communication timing calculation means 1 and the tuning determination means 4.

  Here, the timing control signal is a control signal indicating the transmission timing of the own node. The timing control signal may be, for example, a signal having an impulse-like waveform (a concept including a waveform-shaped signal), but is not limited thereto, and is a signal composed of a packet or the like. Good. In FIG. 2, a transmission timing signal is indicated as an output timing signal, and a reception timing control signal is indicated as an input timing signal.

  The timing control signal transmission unit 3 receives phase information from the communication timing calculation unit 1 and transmits an output timing control signal. Note that the transmission timing of the timing control signal is preferably a timing at which the phase signal has a predetermined phase (for example, α (0 ≦ α <2π)), and is preferably unified throughout the system, for example.

  The tuning determination means 4 determines whether the mutual adjustment of the output timing control signal transmission timing performed between the own node or one or a plurality of neighboring nodes is in a “transient state” or a “steady state”. To do. As this determination method, for example, when the generation timings of the input timing control signal and the output timing control signal are observed, and the time difference between the generation timings of a plurality of nodes that exchange timing control signals is stable in time. It determines with it being "steady state", and when that is not right, it determines with "excessive state." In the case of this embodiment, the tuning determination unit 4 receives from the communication timing calculation unit 1 as a signal for capturing the generation timing of the output timing control signal from the own node, instead of the output timing control signal. Phase information (phase signal) is input.

  Further, the tuning determination means 4 provides the data communication means 5 with a tuning determination signal indicating a determination result for each period of the phase signal and a slot signal indicating the minimum value of the phase signal at the generation timing of the input timing control signal. give.

  The sensor 6 is for observing physical or chemical environmental information such as intensity of sound or vibration, chemical substance concentration, temperature, and the like, and provides observation data to the data communication means.

  The data communication means 5 transmits observation data and / or input data signals (including both cases) as an output data signal to other nodes. When the tuning determination signal indicates “steady state”, the data communication means 15 uses a time slot (which is not a fixed time interval assigned by the system or the like, but uses the term “time slot”). When the tuning determination signal indicates “transient state”, the transmission operation is stopped. The output data signal may be a transmission frequency in the same frequency band as the output timing control signal.

  As for the time slot, the start point of the time slot is the timing at which the transmission of the output timing control signal is completed, and the end point of the time slot is slightly different from the timing of the first input timing control signal for each period of the phase signal. The previous timing is set by the offset.

(A-1-3) Detailed Configuration of Communication Timing Calculation Unit 1 Next, a detailed configuration of the communication timing calculation unit 1 according to the first embodiment will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the internal configuration of the communication timing calculation means 1 of the first embodiment. In FIG. 1, the communication timing calculation unit 1 of the first embodiment is configured to include at least a neighboring node state management unit 11, a required phase difference calculation unit 12, a phase response function adjustment unit 13, and a phase dynamics unit 14. The

  When the neighboring node state management means 11 receives the timing control signal of the neighboring node, the neighboring node address information, the phase difference Δθij between the timing control signal of the neighboring node and the timing control signal of the own node, the timing control signal of the neighboring node Information such as signal reception intensity is obtained and managed while sequentially updating the information. The neighboring node state management unit 11 may delete analysis information that has become obsolete after a certain period of time.

  The neighboring node state management means 11 gives address information of the neighboring nodes to be managed to the required phase difference calculation means 12 and gives the phase difference Δθij between the neighboring nodes and the own node to the phase dynamics means 14.

  Here, the phase difference Δθij between the neighboring node and the own node is obtained by subtracting the phase value θi (t) of the timing control signal of the own node i from the phase value θj (t) of the timing control signal of the neighboring node j. It is a phase difference. The neighboring node state management unit 11 sequentially receives the phase value of the own node obtained by the phase dynamics unit 14 and obtains the phase difference between the neighboring node and the own node using the phase value of the own node.

  The required phase difference calculation means 12 obtains a communication time that the neighboring node wants to secure based on information analyzed based on the timing control signal of the neighboring node. Thereby, the required phase difference calculation means 12 can manage how much time transmission right the neighboring node needs. Further, the required phase difference calculation means 12 obtains the communication time that the own node wants to secure. Further, the required phase difference calculation means 12 gives the phase response calculation means the communication time that each of its own node and neighboring nodes wants to secure.

  Here, in the first embodiment, a case will be described in which the required phase difference calculation unit 12 obtains a communication time that the neighboring node wants to secure based on the address information of the neighboring node.

  That is, the required phase difference calculation means 12 analyzes the position information of the neighboring nodes in the wireless communication network structure based on the neighboring node address information received from the neighboring node state management means 11, and secures the neighboring nodes based on this. The communication time desired is determined, and the phase difference (required phase difference) φcj corresponding to the communication time desired to be secured for this neighboring node is obtained. Further, the required phase difference calculation means 12 obtains a phase difference (required phase difference) φc corresponding to the communication time to be secured by the own node.

  As a method for obtaining the required phase difference φcj related to the neighboring node, for example, there is the following method.

  For example, it is assumed that the wireless communication network NT of the first embodiment is configured with a cluster tree structure used in Zigbee or the like. In this case, a network address according to the cluster tree structure is assigned to each node A and sink node S according to a certain rule for management. For example, the depth of the tree (Lm), the number of devices that can be connected to one ZigBee router (Cm), of which the number of devices that can be connected as a ZigBee router (Rm) are determined. Address assignment based on rules. Thereby, a device to be transferred can be determined based on the address information without having a routing table.

  In this case, the required phase difference calculation means 12 can recognize the depth of the neighboring node (that is, the depth of each node in the cluster NT network NT) from the address information of the neighboring node. Therefore, since the required phase difference calculation means 12 generally has more packets to be relayed as the node is closer to the sink node S and requires more transmission time, the simplest example is as shown in the following equation (1). The communication time can be determined linearly from the depth of the node.

φcj = α (Lm−dj + 1) φb (1)
Here, Lm indicates the depth of the tree, dj indicates the depth of the node j, and φb indicates the basic allocation time. Α is a coefficient and can be determined experimentally.

  As a method for obtaining the required phase difference φc related to the own node, the phase width corresponding to the minimum time slot size Wmin necessary for the node to transmit the data signal is calculated by φc = Wmin × ωi. can do. ω i is a natural frequency parameter at its own node i, and W min is a constant parameter determined according to the application.

  The phase response function adjusting unit 13 receives the required phase difference φcj of the neighboring node and the required phase difference φc of the own node from the required phase difference calculating unit 12, and calculates the required phase difference related to these neighboring nodes and the required phase difference φc of the own node. Based on this, the phase response function R (Δθij (t)) is updated.

  The phase response function R (Δθij (t)) is a function that constitutes a time evolution rule used when calculating the transmission timing of the timing control signal of the own node, and forms an equal phase difference between neighboring nodes. Is to do. That is, the phase response function R (Δθij (t)) acts on the mechanical characteristics so that the phase difference distribution between the own node and the neighboring nodes becomes equal, and the size of the time slot acquired between the neighboring nodes. Has the characteristic of substantially equalizing.

  Thereby, in the relationship with the neighboring node transmitted after the own node, the phase difference from the phase value of the own node to the phase value of the neighboring node is only the required phase difference φc corresponding to the communication time desired to be secured by the own node. It can be adjusted to be away. Also, in the relationship with the neighboring node that is transmitted before the own node, the phase value from the neighboring node to the own node is adjusted so that it is separated by φcj corresponding to the communication time that the neighboring node j wants to secure. can do.

  The phase dynamics means 14 receives the phase difference between the own node and the neighboring node from the neighboring node state management means 11 and also receives the phase response function R (Δθij (t)) adjusted by the phase response function adjusting means 13. The transmission timing of the timing control signal of the own node is calculated using the phase difference between the own node and the neighboring node and the adjusted phase response function R (Δθij (t)).

  As a method for calculating the transmission timing of the timing control signal of the own node, various methods can be applied. For example, the method described in any of Patent Documents 1 to 4 can be applied. The details of the method of calculating the transmission timing of the timing control signal of the own node are left to the description of each of Patent Documents 1 to 4, and detailed description thereof is omitted here.

(A-2) Operation of the First Embodiment Next, the operation of the processing for calculating the transmission timing of the timing control signal in the own node of the first embodiment will be described with reference to FIG.

  First, when the timing control signal transmitted from the neighboring node arrives at its own node, the timing control signal is received by the timing control signal receiving unit 2 and given to the neighboring node state management unit 11.

  In the neighboring node state management means 11, at least address information of neighboring nodes included in the timing control signal and a phase difference between the neighboring nodes and the own node are analyzed, and a phase difference between the neighboring nodes and the own node is analyzed as the phase dynamics means 14. Given to. Here, although the case where the neighboring node state management means 11 analyzes the address information of the neighboring node and the phase difference between the neighboring node and the own node has been shown, the received signal strength of the timing control signal may be managed. Good.

  As a result, the phase dynamics means 14 calculates and outputs the transmission timing of the timing control signal of the own node according to the time evolution rule.

  Also, the neighboring node state management unit 11 gives the address information of the neighboring node to be managed to the required phase difference calculation unit 12.

  The required phase difference calculation means 12 calculates the required phase difference φcj of the neighboring node and the required phase difference φc of the own node based on the address information of the neighboring node received from the neighboring node state management means 11, and The required phase differences φcj and φc of the node are given to the phase response function adjusting means 13.

  In the phase response function adjusting means 13, the phase response function is adjusted based on the required phase differences φcj and φc of the neighboring node and the own node from the required phase difference calculating means 12, and the adjusted phase response function is supplied to the phase dynamics means 14. Given.

  Thereby, in the phase dynamics means 14, the phase response function which determines the transmission timing of a timing control signal is reconfigure | reconstructed, and the communication timing pattern reflecting the required phase difference of each node is formed.

  FIG. 4 shows the shape of the phase response function R (Δθij (t)) adjusted by the phase response function adjusting means 13. The convergence state is determined by the shape of the phase response function R (Δθij (t)).

  For example, the phase difference Δθij = θj−θi (θj is the phase value of the neighboring node j and θi is the phase value of the own node i) is assumed. When one period corresponds to 2π, when the phase difference with a certain neighboring node j is (0 to π), the neighboring node j is a node that communicates earlier than itself, and the phase difference with a certain neighboring node j When is (π-2π), the neighboring note j can be regarded as a node communicating after itself.

  That is, as shown in FIG. 4, the shape of the phase response function adjusted by the phase response function adjusting means 13 is equal to the required phase difference φc corresponding to the communication time desired to be secured from the node transmitting after the own node. It is necessary to be separated, and a phase difference can be formed by φcj corresponding to the communication time that the neighboring node j wants to secure from the neighboring node j that is transmitted before its own node. This is different for each neighboring node j.

(A-3) Effect of First Embodiment As described above, according to the first embodiment, a required phase difference according to the depth of a node in the network structure is used based on address information of neighboring nodes. By reconfiguring the optimal phase response function considering the required phase difference of each node, the optimal communication timing pattern with neighboring nodes can be formed, so the communication timing can be optimized. , Increase the efficiency of data communication.

(B) Second Embodiment Next, a communication timing control device, a communication timing control method, a communication timing control program, a node, and a communication system according to a second embodiment of the present invention will be described with reference to the drawings.

(B-1) Configuration of the Second Embodiment FIG. 5 is a block diagram showing the internal configuration of the communication timing calculation means 20 of the second embodiment. In FIG. 5, the communication timing calculation unit 20 of the second embodiment is configured to include at least a neighboring node state management unit 21, a required phase difference calculation unit 22, a phase response function adjustment unit 13, and a phase dynamics unit 14. The

  The communication timing calculation unit 20 of the second embodiment is different from the communication timing calculation unit 1 of the first embodiment in that the required phase difference determination method by the required phase difference calculation unit 22 is different. Further, the connection configuration of the neighboring node state management unit 21 is different from the configuration of the first embodiment.

  The neighboring node state management means 21 receives the timing control signal from the neighboring node, and similarly to the first embodiment, the address information of the neighboring node, the phase difference between the timing control signal of the neighboring node and the timing control signal of the own node, It manages the signal reception intensity of the timing control signal of the neighboring node. Further, the neighboring node state management means 21 of the second embodiment gives the phase dynamics means 14 the phase difference between the timing control signals of the neighboring node and the own node.

  The required phase difference calculation means 22 receives network topology information from the sink node S and determines the required phase difference based on the network topology information. The required phase difference calculation means 21 gives the determined required phase difference of the neighboring nodes and the required phase differences φcj and φc of the own node to the phase response function adjusting means 13.

  Here, in the second embodiment, the sink node S recognizes the number of downstream nodes to which each node constituting the wireless communication network NT is directly connected. In addition, the sink node S periodically or constantly notifies the number of downstream nodes to which each node is directly connected to each node.

  Note that the information regarding the number of downstream nodes of each node may be notified to each node as a signal different from the timing control signal, or may be included in the timing control signal.

  The phase response function adjusting means 13 receives the number of downstream nodes from the sink node S as network topology information, and determines the required phase difference based on the number of downstream nodes.

  For example, assuming that the number of downstream nodes directly connected to node j is Nj and the basic allocation time is φb, the required phase difference φcj of node j is obtained according to the following equation (2).

φcj = α × Nj × φb (2)
Α is a coefficient and can be determined experimentally.

  By determining the required phase difference of node j according to the above equation (2), the required phase difference can be determined according to the number of downstream nodes to which node j is directly connected, so the number of downstream nodes is large. In this case (that is, when there is a lot of traffic), it is possible to set a large number of required phase differences for the node.

(B-2) Operation of the Second Embodiment Next, the operation of the processing for calculating the transmission timing of the timing control signal in the own node of the second embodiment will be described with reference to FIG.

  First, when the timing control signal transmitted from the neighboring node arrives at its own node, the timing control signal is received by the timing control signal receiving unit 2 and given to the neighboring node state management unit 21.

  In the neighboring node state management means 21, at least the phase difference between the neighboring node and the own node is analyzed and the phase difference between the neighboring node and the own node is given to the phase dynamics means 14.

  The phase dynamics means 14 calculates and outputs the transmission timing of the timing control signal of the own node according to the time evolution rule.

  On the other hand, the sink node S recognizes the number of downstream nodes directly connected to each node constituting the wireless communication network NT, and uses the number of downstream nodes directly connected to each node as network topology information for each node. To notify periodically or constantly.

  Here, as a method for obtaining the number of downstream nodes of each node by the sink node S, various methods are conceivable and are not particularly limited. For example, there are the following methods.

  For example, in the wireless communication network NT such as a sensor network, each node transmits the data signal from the downstream node to the sink node S when receiving the data signal from the downstream node directly connected thereto.

  Thereby, since the sensor node S can recognize the downstream node of each node based on the transfer locus of the data signal from the downstream node, by calculating the total number of nodes of the downstream node for each node, The number of downstream nodes of each node can be obtained.

  When the network topology information from the sink node S arrives at each node, the network topology information is given to the required phase difference calculation means 22 of the node.

  In the required phase difference calculating means 22, the required phase difference φcj is determined according to the equation (2) based on the node information of the downstream node from the sink node S, and the required phase difference φcj is given to the phase response function adjusting means 13. It is done.

  In the phase response function adjusting means 13, the phase response function R (Δθij (t)) is adjusted based on the required phase difference φc of its own node and the required phase difference φcj of the neighboring nodes, as in the first embodiment. The

  Then, the transmission timing of the timing control signal of the own node is calculated and output by the phase dynamics means 14.

(B-3) Effects of Second Embodiment As described above, according to the second embodiment, the same effects as those of the first embodiment can be obtained.

  In the second embodiment, each node can obtain the required phase difference based on the network topology information managed globally by the sink node S. Therefore, a more optimal communication timing pattern can be formed, and communication can be performed. The timing can be optimized and the efficiency of data communication can be realized.

(C) Third Embodiment Next, a communication timing control device, a communication timing control method, a communication timing control program, a node, and a communication system according to a third embodiment of the present invention will be described with reference to the drawings.

(C-1) Configuration of the Third Embodiment FIG. 6 is a functional block diagram showing the internal configuration of the communication timing calculation means 30 of the third embodiment. In FIG. 6, the communication timing calculation unit 30 of the third embodiment is configured to include at least a neighboring node state management unit 31, a required phase difference determination unit 32, a phase response function adjustment unit 33, and a phase dynamics unit 14. The

  The communication timing calculation unit 30 of the third embodiment is different from the communication timing calculation unit 1 of the first embodiment in that it does not include a required phase difference calculation unit, but includes a required phase difference determination unit 32 instead. For example, the required phase difference determined at each node is transmitted on the timing control signal, and therefore, the neighboring node state management means 31 analyzes and manages the required phase difference.

  When the neighboring node state management means 31 receives the timing control signal from the neighboring node, each of the neighboring node address information, the phase difference of the timing control signal between the neighboring node and the own node, the required phase difference of the neighboring node, etc. This is managed for each neighboring node. The neighboring node state management means 31 gives the required phase difference of each neighboring node to the phase response function adjusting means 33 and also gives the phase difference of the timing control signal between the neighboring node and the own node to the phase dynamics means 14. .

  In the third embodiment, as described above, the required phase difference determined by each node is transmitted on the timing control signal. Therefore, in the third embodiment, the neighboring node state managing unit 31 reads the required phase difference of the neighboring node included in the timing control signal and gives the required phase difference of the neighboring node to the phase response function adjusting unit 33. Thus, the phase response function is adjusted.

  The neighboring node state management means 31 has a required phase difference measurement function for managing the required phase difference of neighboring nodes and measuring the sum of the required phase differences when traffic occurs. In order to prevent the upper limit of the radio band from being exceeded, the neighboring node state management unit 31 has a predetermined threshold value, and when the total of the required phase differences exceeds the threshold value, the required phase difference of the own node Has a required phase difference control function for controlling so as to reduce. As a result, when the data rate related to traffic from the neighboring node increases and exceeds the radio band, the communication time of the own node can be shortened and changed according to the increase in traffic from the neighboring node. .

  The required phase difference determining unit 32 determines the required phase difference of the own node based on the required phase difference of each neighboring node managed as the neighboring node state by the neighboring node state managing unit 31. The required phase difference determining means 32 transmits the determined required phase difference of its own node on the timing control signal.

  Here, in the third embodiment, the required phase difference determining unit 32 determines the required phase difference of the own node with reference to the past generated traffic from the neighboring node state managed by the neighboring node state managing unit 31. .

  For example, the required phase difference determining unit 32 observes traffic (including data relay) generated in the past S seconds based on the neighboring node state of the neighboring node state management unit 31 and determines the traffic generation rate per unit time. decide. Then, the required phase difference of the own node is determined according to this generation rate, and is put on the timing control signal.

(C-2) Operation of the Third Embodiment Next, the operation of the processing for calculating the transmission timing of the timing control signal in the own node of the third embodiment will be described with reference to FIG.

  First, when the timing control signal transmitted from the neighboring node arrives at its own node, the timing control signal is received by the timing control signal receiving unit 2 and given to the neighboring node state management unit 31.

  The neighboring node state management means 31 analyzes at least the phase difference between the neighboring node and the own node, the address information of the neighboring node, the required phase difference of the neighboring node, and the required phase difference is given to the phase response adjusting means 33. The phase difference between the neighboring node and the own node is given to the phase dynamics means 14.

  The phase response function adjustment means 33 adjusts the phase response function based on the required phase difference from the neighboring node state management means 31, and the phase dynamics means 14 adjusts the phase response function adjusted by the phase response function adjustment means 33. Is used to obtain the timing control signal of its own node.

  On the other hand, the required phase difference determining unit 32 determines whether the required phase difference of the own node is autonomous according to the data rate of the generated traffic based on the neighboring node state for each neighboring node managed by the neighboring node state managing unit 31. To be determined.

  For example, the required phase difference determining means 32 sets a predetermined mathematical expression in advance so that the required phase difference of the own node is reduced as the data rate of the generated traffic increases, and the required phase difference of the own node is determined using this mathematical expression. The phase difference can be determined. Further, for example, the required phase difference determining means 32 is provided with a table indicating a correspondence relationship between the data rate of the generated traffic and the required phase difference of the own node, so that the required phase difference of the own node is determined. Also good.

  The determined required phase difference of the own node is put on the timing control signal by the required phase difference determining means 32.

  In this way, by putting the required phase difference of each node on the timing control signal, the required phase difference of each neighboring node can be known directly without each node obtaining it, and the phase response function is reconfigured to determine the communication timing. Can be optimized.

  The neighboring node state management unit 31 measures the total sum of the required phase differences, compares the total sum of the required phase differences with a threshold value, and determines whether the total sum of the required phase differences exceeds the threshold value.

  If it is determined that the sum of the required phase differences is a threshold value, the neighboring node state management means 31 instructs the required phase difference determination means 32 to reduce the required phase difference of the own node.

(C-3) Effects of Third Embodiment As described above, according to the third embodiment, the same effects as those of the first embodiment can be obtained.

  Further, according to the third embodiment, the required phase difference of the other node is directly received by transmitting the required phase difference of the own node autonomously determined by the own node to the other node on the timing control signal. Communication timing patterns can be easily formed.

(D) Other Embodiments In the first embodiment described above, the case where the communication time (required phase difference) of a node is determined based on the depth (layer) of the node has been described. However, the present invention is not limited to this, and it may be determined based on the signal reception strength of the timing control signal.

  In this case, for example, when the reception strength of the timing control signal is high, a predetermined mathematical formula is set in advance so as to increase the required phase difference of the neighboring node that transmitted the timing control signal. Then, the required phase difference calculation means can be realized by calculating the required phase difference of neighboring nodes according to the mathematical formula based on the timing control signal.

  In the first to third embodiments described above, a sensor network in which each node transmits sensor data is illustrated as an example of a wireless communication network. However, the present invention is not limited to a sensor network, and can be widely applied to any wireless communication network that realizes wireless communication by forming communication timing between nodes in an autonomous and distributed manner.

  In the first to third embodiments, if the method of calculating the phase of the timing control signal of the own node calculated by the phase dynamics means uses a time evolution rule having a phase response function, Patent Documents 1 to The method is not limited to the method disclosed in Document 4, and can be widely applied.

  The above embodiment has been described assuming a system in which a large number of nodes distributed in a space exchange data with each other wirelessly. However, the utilization form of the present invention is not limited to a system that performs wireless communication. The present invention can also be applied to a system in which a large number of nodes distributed in a 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 wired sensors or actuators or servers. Of course, the present invention can be applied to a network in which nodes connected by wire and nodes connected wirelessly are mixed.

  The functions realized by the communication timing calculation means in the first to third embodiments are assumed to be based on software processing in which hardware resources are executed by executing a processing program. You may make it implement | achieve by the hardware comprised by these.

It is a block diagram which shows the internal structure of the communication timing calculation means of 1st Embodiment. 1 is a configuration diagram illustrating an overall configuration of a wireless communication network according to a first embodiment. It is a block diagram which shows the structure of the node of 1st Embodiment. It is explanatory drawing which shows the shape of the adjusted phase response function of 1st Embodiment. It is a block diagram which shows the internal structure of the communication timing calculation means of 2nd Embodiment. It is a block diagram which shows the internal structure of the communication timing calculation means of 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,20 and 30 ... Communication timing calculation means 11, 21, and 31 ... Neighboring node state management means, 12 and 22 ... Required phase difference calculation means, 32 ... Required phase difference determination means, 13 and 33 ... Phase response function adjustment means , 14 ... phase dynamics means, NT ... wireless communication network, A ... node, S ... sink node.

Claims (9)

A communication timing control device provided in a node constituting a communication system, using communication timing of a timing control signal from another node, determining communication timing of a timing control signal of the own node, and controlling the timing of the own node In the communication timing control device for determining the transmission period of the data signal based on the communication timing of the signal and the communication timing of the timing control signal of the other node,
Timing control signal transmitting / receiving means for transmitting / receiving the timing control signal to / from another node;
Based on the required transmission period necessary for transmitting the data signal of the own node and the required transmission period required for transmitting the data signal of the other node, the communication timing relationship of the timing control signal of the own node and the other node is determined. A phase response function adjusting means for adjusting the phase response function;
Communication timing calculation means for calculating the communication timing of the timing control signal of the own node according to a predetermined time evolution rule using the phase response function adjusted by the phase response function adjustment means. Communication timing control device.   The phase response function adjusting means recognizes the depth of the other node constituting the tree network with reference to the address information of the other node, and determines the required transmission period of the other node based on the depth of the other node. The communication timing control device according to claim 1, wherein the communication timing control device is determined.   The phase response function adjusting means receives the node number information of the downstream node of each node from the outside, and determines the required transmission period of the other node according to the node number information of the downstream node of each node. The communication timing control device according to claim 1. According to the data rate of traffic that occurred in the past, the required transmission period of the own node is determined, and the required transmission period determining means for including the determined required transmission period of the own node in the timing control signal,
The phase response function adjusting means adjusts the phase response function based on a required transmission period of another node included in the timing control signal received by the timing control signal transmitting / receiving means. The communication timing control device according to 1.   5. The communication timing according to claim 4, wherein the timing control signal transmission / reception means manages the sum of the required transmission periods of the other nodes and manages the communication band by comparing the sum of the required phase differences with a threshold value. Control device. A communication timing control method provided in a node constituting a communication system, wherein communication timing of a timing control signal of a local node is determined using a communication timing of a timing control signal from another node, and timing control of the local node In the communication timing control method for determining the transmission period of the data signal based on the communication timing of the signal and the communication timing of the timing control signal of the other node,
A timing control signal transmitting / receiving step for transmitting and receiving the timing control signal to and from another node;
Based on the required transmission period necessary for the transmission of the data signal of the own node and the required transmission period required for the transmission of the data signal of the other node, the phase response function adjusting means determines the timing control signal of the own node and the other node. A phase response function adjusting step for adjusting a phase response function for determining the communication timing relationship of
A communication timing calculation step in which a communication timing calculation means calculates the communication timing of the timing control signal of the own node according to a predetermined time development rule using the phase response function adjusted by the phase response function adjustment means; A communication timing control method comprising: A communication timing control program provided in a node constituting a communication system, using a communication timing of a timing control signal from another node, determining a communication timing of a timing control signal of the own node, and controlling the timing of the own node In the communication timing control program for determining the transmission period of the data signal based on the communication timing of the signal and the communication timing of the timing control signal of the other node,
On the computer,
Timing control signal transmitting / receiving means for transmitting / receiving the timing control signal to / from another node;
Based on the required transmission period necessary for transmitting the data signal of the own node and the required transmission period required for transmitting the data signal of the other node, the communication timing relationship of the timing control signal of the own node and the other node is determined. A phase response function adjusting means for adjusting the phase response function;
A communication timing control program that functions as communication timing calculation means for calculating the communication timing of the timing control signal of its own node according to a predetermined time development rule using the phase response function adjusted by the phase response function adjustment means.   A node constituting the communication system comprises the communication timing control device according to claim 1.   A communication system comprising a plurality of nodes according to claim 8.

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