JP4196886B2 - Communication timing control device, communication timing control method, node, and communication system - Google Patents

Description

  The present invention relates to a communication timing control device, a communication timing control method, a node, and a communication system, and more particularly to data communication collision avoidance in a communication system including a plurality of nodes.

  As a system for enabling data communication without a collision between a plurality of nodes distributed in space, there are a TDMA system, a CSMA (CSMA / CA and CSMA / CD) system, and the like (see Non-Patent Document 1). .

  In the CSMA method, a node to be transmitted confirms whether or not another node is communicating based on the presence of a carrier (frequency), and transmits when communication is not being performed. However, in the case of the CSMA system, the number of channels that can be simultaneously communicated decreases.

In the TDMA system, different time slots are assigned to each node, and each node performs data transmission in the time slot assigned to itself. The TDMA system can easily increase the number of channels that can be simultaneously communicated as compared to the CSMA system. . In the TDMA system, when a node used for communication changes dynamically, a certain node (management node) dynamically assigns a time slot to each node.
Matsushita Atsushi, Nakagawa Masao, “Wireless LAN Architecture”, Kyoritsu Shuppan, 1996, p. 47, 53-59, 69

  However, in the case of the TDMA system, if the management node that performs time slot allocation fails, the entire communication system goes down. Also, the process of dynamically reassigning time slots to each node is complicated, and it may not be possible to respond quickly to changes in the situation. Furthermore, in the case of the TDMA system, the time slot width cannot be changed only for some nodes.

  Therefore, a communication timing control device and a communication timing that are highly flexible so that each node can execute effective communication without instructing the communication timing to each node by the management node, and that can easily cope with reassignment of time slots. Control methods, nodes and communication systems are desired.

The first present invention is a communication timing control apparatus provided in each of a plurality of nodes constituting the communication system, the receive state variable signal indicating the operation timing of (1) other nodes, its own node a state variable signal communication means for transmitting a state variable signal indicating the operation timing of the intermittently, based on the (2) state variables signal and the basic speed information of the transition from the other node receives the state variable signal communication unit transitions the operation timing of the own node, generates a state variable signal from the local node that reflects this transition with given to the state variable signal communication unit, one or the vicinity of the own node and state variable signal reaches Timing determining means for recognizing time slots in which a plurality of other nodes can transmit data; and (3) a periodic time determined by the operation timing of the own node. Data transmission means for transmitting a data signal for each lot; (4) data reception means for receiving a data signal from another node; and (5) time slot width change determination for determining whether or not the time slot width of the own node can be changed. And (6) an operation timing shift means for forcibly shifting the operation timing of the own node in the timing determination means when it is necessary to change the time slot width of the own node. To do.

  A node according to a second aspect of the present invention includes the communication timing 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.

The fourth of the present invention is a communication timing control method, each of the plurality of nodes constituting the communication system is executed, the receive state variable signal indicating the operation timing of (1) other nodes, the own node movement A state variable signal communication step for intermittently transmitting a state variable signal indicating the operation timing; and (2) based on the state variable signal received from the other node in the state variable signal communication step and the basic speed information of the transition. It shifts the operation timing of the node, with giving to the state variable signal communication process to generate a state variable signal from the local node that reflects this transition, near the own node and state variable signal reaches 1 or more A timing determination step for recognizing a time slot in which another node can transmit data; and (3) a periodic time slot determined by the operation timing of the own node. A data transmission step for transmitting a data signal every time, (4) a data reception step for receiving a data signal from another node, and (5) a time slot width change determination step for determining whether or not the time slot width of the own node can be changed. And (6) an operation timing shift step of forcibly shifting the operation timing of the own node in the timing determination step when it is necessary to change the time slot width of the own node.

  According to the communication timing control device, the communication timing control method, the node, and the communication system of the present invention, each node is highly flexible to perform effective communication even when there is no management node. Allocation can be easily handled.

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

  In the first embodiment, each node generates an impulse signal, and by effectively detecting an impulse signal generated by a node other than itself, the nodes interact with neighboring nodes, and time is distributed autonomously. Slot allocation is determined, and reallocation after the allocation is determined can be easily performed.

(A-1) Configuration of the First Embodiment FIG. 2 is a block diagram showing an example of node arrangement in the network intended by the first embodiment, and shows the nodes N1 and N2 as nodes of interest. .

  In FIG. 2, solid circles centered on the nodes of interest N1 and N2 indicate a range in which the nodes N1 and N2 can receive an impulse signal (described later) transmitted by another node. In the example of FIG. 2, the target node N1 can receive the impulse signals transmitted from the nodes N2, N3, and N9, and the target node N2 can receive the impulse signals transmitted from the nodes N1, N3 to N12.

  A dotted circle centered on the target nodes N1 and N2 in a range narrower than the solid circle indicates a range in which the other nodes and the target nodes N1 and N2 can exchange data signals. In the example of FIG. 2, the node of interest N1 can exchange data signals only with the node N3, and the node of interest N2 can exchange data signals with the nodes N3, N7, N8.

  The first embodiment is intended to allocate time slots at each node as evenly as possible (including the case by reassignment) even if there is a bias in the arrangement of the nodes as described above. .

  FIG. 1 is a block diagram illustrating an internal configuration of each node according to the first embodiment. In FIG. 1, each node includes an impulse signal receiving unit 11, a communication timing calculating unit 12, an impulse signal transmitting unit 13, a tuning determination unit 14, a data communication unit 15, a time slot width measuring unit 16, and an angular velocity changing unit 17.

  The impulse signal receiving unit 11 receives an impulse signal (not including destination information) transmitted by a nearby node (for example, another node existing in a range where a transmission radio wave of the node reaches). 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 impulse signal receiving unit 11 gives the received impulse signal itself, a waveform of the impulse signal itself, or an impulse signal regenerated based on the received impulse signal to the communication timing calculation unit 12 and the tuning determination unit 14.

The communication timing calculation means 12 forms and outputs a phase signal that defines the communication timing at the node based on the signal given from the impulse signal reception means 11. Here, assuming that the node is the node i and the phase value of the phase signal at the time t is θi (t), the communication timing calculation unit 12 changes the phase signal θi ( t) is changed. The expression (1) is an expression modeling nonlinear vibration, but an expression modeling other nonlinear vibration can also be applied. Further, the phase signal θi (t) can be regarded as a state variable signal of the node.

  Expression (1) represents a rule for changing the rhythm of nonlinear vibration of the phase signal θi (t) of the own node i in accordance with the signal given from the impulse signal receiving means 11. In the equation (1), the first term ω (natural angular frequency parameter) on the right side represents a basic change rhythm (corresponding to “basic speed for transitioning its own operation state”) included in each node, The second term on the right side represents the nonlinear change. Here, the value of ω is, for example, the same value throughout the system. The function Pk (t) represents the signal output from the impulse signal receiving means 11 based on the impulse signal received from the neighboring node k, and the function R (θi (t), σ (t)) This is a phase response function that expresses a response characteristic that changes its basic rhythm in response to the reception of an impulse signal from, for example, according to equation (2).

  Expression (2) represents that the phase response function is defined by a sine wave having a phase value in which random noise is superimposed on the opposite phase of the phase signal θi (t) at time t. Non-linear characteristics in which neighboring nodes are in opposite phases (vibration phase is inverted phase) are realized, and collision avoidance is attempted using the characteristics. That is, an appropriate time relationship (time difference) is formed at the timing when the phase signal value of each node becomes the same value so that the transmission timing of the impulse signal between adjacent nodes does not collide.

  In the equation (2), the constant term π [rad] representing the function σ (t) functions as a non-linear characteristic in which neighboring nodes are out of phase with each other, and the random noise function φ (t) It functions to give random variability to the nonlinear characteristic (the function φ (t) follows, for example, a Gaussian distribution with an average value of 0). Here, the reason why random variability is given to the non-linear characteristic is to deal with a phenomenon that the system does not reach the target stable state (optimal solution) and falls into another stable state (local solution). Because.

  In the equation (2), the form using the sine function is shown as the simplest example of the phase response function R (θi (t), σ (t)), but other functions may be used as the phase response function. good. Further, instead of the constant term π of the function σ (t), a constant λ other than π (0 <λ <2π) may be used. In this case, neighboring nodes are not in antiphase but in different phases. Function.

  The meaning of the above-described function of the communication timing calculation means 12 will be described in detail with reference to FIGS. 3 and 4 show the relationship formed between a target node (own node) i and a neighboring node (other node) j, that is, each nonlinear vibration rhythm when attention is paid to a certain node i. The phase relationship between them changes with time.

  FIG. 3 shows a case where there is one neighboring node j for the node of interest i. In FIG. 3, 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 equations (1) and (2), the two mass points try to be in opposite phases to each other, and the phases of the two mass points are close to each other in the initial state as shown in FIG. However, with the passage of time, the state (transient state) shown in FIG. 3B changes to a steady state in which the phase difference between the two mass points is approximately π as shown in FIG. 3C.

  Each of the two mass points rotates with the natural angular frequency parameter ω as a basic angular velocity (corresponding to a basic velocity for transitioning 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) the 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 each node transmits an impulse signal at a predetermined phase α (for example, α = 0), the transmission timing at each node forms an appropriate time relationship. Will be.

  FIG. 4 shows a case where there are two neighboring nodes j1 and j2 for the node of interest i. Even in the case where there are two neighboring nodes, a stable phase relationship (stability related 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.

  3 and 4 show the case where one or two other nodes transmit and receive the impulse signal in the vicinity of the node of interest. However, as illustrated in FIG. The arrangement relationship is more complicated than those assumed in FIGS. 3 and 4.

  The communication timing calculation unit 12 outputs the obtained phase signal θi (t) to the impulse signal transmission unit 13, the tuning determination unit 14, the data communication unit 15, and the time slot width measurement unit 16.

  The impulse signal transmission means 13 transmits and outputs an impulse signal based on the phase signal θi (t). That is, when the phase signal θi (t) reaches a predetermined phase α (0 ≦ α <2π), an impulse signal is transmitted and output. 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. 3, since the phase signals θi (t) and θj (t) in the steady state are shifted by π at the node i and the node j, the entire system is unified to α = 0. However, the transmission timing of the impulse signal from the node i and the transmission timing of the impulse signal from the node j are shifted by π.

  The tuning determination unit 14 is configured so that mutual adjustment of the transmission timing of the output impulse signal performed between the own node and one or a plurality of neighboring nodes is “transient state” (see FIGS. 3B and 4B) or It is determined which state is the “steady state” (see FIG. 3C or FIG. 4C). The tuning determination means 14 observes the reception timing of the impulse signal (corresponding to the output timing of the other node) and the transmission timing of the impulse signal from its own node, and the time difference between the transmission timings of a plurality of nodes that exchange the impulse signal Is determined to be in a “steady state” when it is stable over time. A phase signal θi (t) is input to the tuning determination unit 14 as a signal for capturing the transmission timing of the impulse signal from the own node.

  The tuning determination unit 14 performs the tuning determination by executing the following processes (a) to (d), for example.

  (A) The value β of the phase signal θi (t) at the output timing of the signal from the impulse signal receiving means 11 is observed over one period of the phase signal θi (t). As a result of the above observation, the values β of the phase signals θi (t) obtained are set to β1, β2,..., ΒN (0 <β1 <β2 <... ΒN <2π), respectively.

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

  (C) The processes of (a) and (b) are performed for each period of the phase signal θi (t), and the amount of change (difference) 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 θi (t), and τ + 1 indicates the next cycle of the phase signal θi (t).

  (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 signals.

  The tuning determination means 14 performs data by using, as a slot signal, a tuning determination signal indicating a determination result and a minimum value β1 of the value β of the phase signal θi (t) at the reception timing of the impulse signal for each period of the phase signal θi (t). Output to the communication means 15.

  The data communication means 15 receives data from other nodes and transmits data that is the transmission source of itself and data that is relayed by the data communication means 15. The data communication means 15 uses the term “time slot” although the data transmission means a time slot (which is not a fixed time interval assigned by the system or the like described later) when the tuning determination signal indicates “steady state”. ) And the transmission operation is stopped when the tuning determination signal indicates “transient state”.

  The time slot is a period in which the phase signal θi (t) satisfies 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 when the transmission of the impulse signal is finished, 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 received impulse signal for each period of the phase signal. δ1 and δ2 are an impulse signal (including both when the source is the own node and the other node) and a data signal (when the source is the own node and the other node) in the wireless space near the node. Phase width corresponding to a very short time to compensate for the absence of both at the same time.

  For example, in the “steady state” as shown in FIG. 3C, the node i starts transmitting the impulse signal from the phase θi of 0, and ends the transmission of the impulse signal before the phase θi becomes δ1. When the phase θi starts to transmit the data signal from δ1 and the phase θi becomes β1−δ2 (where β1≈π), the transmission of the data signal is terminated, and thereafter, until the phase θi becomes 0 again. The transmission of the impulse signal and the transmission of the data signal 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.

  As described above, the natural angular frequency parameter ω is, for example, unified to the same value in the entire communication system (network). If the natural angular frequency ω is unified, it will be easier to enter the steady state than if it is irregularly distributed at each node. Conversely, if the natural angular frequency ω is not unified, an abnormal impulse signal The number of nodes that transmit the message increases, and it is difficult to enter a steady state.

  In order to review the assigned time slot by the functions of the impulse signal receiving means 11, the communication timing calculating means 12, the impulse signal transmitting means 13, the tuning determining means 14 and the data communication means 15, the time slot width measuring means 16 and Angular velocity changing means 17 is provided. The time slot width measuring unit 16 and the angular velocity changing unit 17 may function when a review activation switch (not shown) is operated, or may always function without waiting for an external operation. .

  The time slot width measuring means 16 measures the reception interval of the impulse signal received by the node. The time slot width measuring means 16 measures the number of received impulses in one cycle (the transmission interval of the impulse signal of the own node), and examines the number of nodes that can transmit / receive the impulse signal to / from the own node. Further, the time slot width measuring means 16 determines whether or not to perform control to increase the assigned time slot width from the time slot width and period assigned to the own node.

  The angular velocity changing means 17 transmits the impulse signal by requesting the communication timing calculating means 12 to change the phase when it is determined that the time slot width measuring means 16 performs control to widen the assigned time slot width. Responsible for shifting the timing.

(A-2) Operation of the First Embodiment Hereinafter, the operation of the communication system of the first embodiment will be described with reference to FIG. 5 as appropriate.

  FIGS. 5A and 5B show the time slot assignment of each node viewed from the nodes N1 and N2 in the case of the node arrangement as shown in FIG. When viewed from the node N1, there are 4 nodes (including the node N1) within the radius R (the radius of the solid circle), and when viewed from the node N2, there are 12 nodes (including the node N2), each of which is one cycle. Is divided into four (FIG. 5A) or 12 (FIG. 5B), and time slots are allocated.

  In FIG. 5, the time slots assigned with “1” to “12” represent the time slots assigned to the node N12 from the node N1 in FIG. Although nodes N1, N2, N3 and N9 are similar nodes, they are affected by the interaction of neighboring nodes, and as shown in FIG. 5 (a), there is a large difference in the width of the assigned time slot. Have. In order to correct such an imbalance of allocation as much as possible (in order to review the allocated time slot), the time slot width measuring means 16 and the angular velocity changing means 17 are provided, and the time slots are reassigned.

  The operation of time slot reassignment is performed in two stages: (1) determination of necessity for time slot width expansion and (2) phase shift control.

(1) Determination of necessity for time slot width expansion The time slot width measurement means 16 of each node counts the number of received impulse signals in one cycle from the transmission of the self impulse signal to the next transmission of the self impulse signal. Then, the number of nodes in the range in which the impulse signal can be received is checked. For example, the time slot width measuring unit 16 of the node N1 receives one impulse impulse from the transmission of the self impulse signal at the timing <1> in FIG. 3A until the next transmission of the self impulse signal. The number of signals is counted, and the number of nodes in the receivable range of the impulse signal is checked. Thereby, the time slot width measuring means 16 of the node N1 obtains the number of nodes “4”. Further, the time slot width measuring unit 16 of each node measures the time from when the impulse signal is transmitted until the impulse signal is received from another node. As a result, the time slot width measuring means 16 of the node N1 performs the time between <1> and <2>, the time between <1> and <3>, <1> and <9 in FIG. By measuring the time between> and organizing these measurement times, the allocated time of each time slot can be obtained.

  When one period is measured as described above, the angular velocity changing unit 17 determines whether or not the time slot allocation width of the own node is smaller than when the time slot allocation width is allocated equally. For example, if the value “2π / number of nodes−time slot width of own node” (here, a difference but may be a ratio) is equal to or smaller than a predetermined threshold value, phase shift control is performed. judge. In the case of the example of FIG. 3A, the time slot width (1) of the node N1 is smaller than that in the case of evenly assigned (4), so it is determined by the angular velocity changing means 17 that the phase shift control is performed.

  Note that the criterion for determining whether or not to perform phase shift control is not limited to this. For example, phase shift control may be performed if the following conditions (A) and (B) are satisfied, and phase shift control is performed when a plurality of conditions are satisfied. Also good.

Condition (A): Time slot width allocated to own node <maximum time slot width / 2
Condition (B): Sum of time slots before and after own impulse signal <maximum time slot width (2) Phase shift control When angular velocity changing means 18 receives an impulse signal defining the end of the time slot of its own node (FIG. 5 (a) <2>) phase θi (t) and the phase difference from phase θi (t + 1) at the time of receiving the next impulse signal (<3> in FIG. 5A) And the phase difference θi (t + 1) −θi (t) is held. Further, the angular velocity changing means 18 checks the phase difference θi (t + 2) −θi (t + 1) at the time of receiving the next impulse signal (<9> in FIG. 5A), and if this phase difference is large, the impulse is changed. The phase θi (t + 1) and the phase difference θi (t + 2) −θi (t + 1) of the signal are held. Such an operation is repeated until the self impulse signal is transmitted again. Then, the transmission phase of the impulse signal of the own node is changed to the held phase + (1/2 of the phase difference). When viewed from the node N1, the time slot assigned to the node N3 is the largest (as seen from the held phase difference), so the phase of the node N1 is shifted to this position and transmission of the impulse signal is started (see FIG. 6).

  FIG. 5C and FIG. 5D are time slot widths viewed from each of the node N1 and the node N2 when the phase shift control is performed. The node N1 has a smaller time slot width due to the influence of the preceding and following nodes, but the allocated width increases.

  The phase shift destination is not limited to the phase within the range of the maximum time slot, but may be other than this. For example, you may make it move to the position where a continuous time slot (next time slot) is the largest.

(A-3) Effect of First Embodiment According to the first embodiment, time slots can be allocated in an autonomous and distributed manner as each node interacts with neighboring nodes.

  In addition, when the time slot allocation width of the own node is smaller than the case where the time slot allocation is evenly allocated, the time slot allocation amount is obtained by detecting the position where the time slot width is wide and shifting the phase to control the communication timing again. Can be increased.

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

  In the second embodiment, when it is determined that the time slot allocation width of the own node is smaller than when the time slot allocation is evenly allocated, the configuration and method for detecting the position where the time slot width is wide and shifting the phase are as follows: Unlike the first embodiment, the second embodiment shifts the phase in consideration of not reducing the data signal reception width as much as possible.

  FIG. 7 is a block diagram showing the internal configuration of the node according to the second embodiment, and the same reference numerals are given to the same and corresponding parts as those in FIG. 1 according to the first embodiment.

  The node according to the second embodiment includes a neighboring node information holding unit 18 in addition to the node configuration according to the first embodiment. The neighboring node information holding unit 18 has a function of holding information such as the time slot width and whether or not the data signal can be transmitted / received for all nodes within the range in which the impulse signal can be received.

  Also in the second embodiment, the necessity for expanding the time slot width is determined in the same manner as in the first embodiment. That is, it is determined whether or not to control the phase shift.

  If it is determined that the phase shift control is to be performed, the impulse signal reception interval is measured, and each time slot width of each node viewed from its own node is examined. Each time slot width is held by the neighboring node information holding means 18. Information indicating whether or not a data signal is being received is input from the data communication means 15 to the neighboring node information holding means 18 to turn on the data flag of the time slot receiving the data signal.

  Information given to the neighboring node information holding unit 18 as described above is held in the neighboring node information holding unit 18 in a table configuration as shown in FIG. FIG. 8 shows a case where the node is N1 and the node N1 is arranged at the position shown in FIG.

  The angular velocity changing means 17 of the second embodiment sets the phase shift destination to a position where data reception is not performed and is within the largest time slot, and shifts the phase here. In the case of the retained information in FIG. 8, no data signal is received at the assigned time slot positions of the neighboring nodes N2 and N9. Of these nodes N2 and N9, the node N9 has a larger time slot width, so that the phase is shifted to a position within the time slot assigned to the node N9 (for example, the phase at the center of the time slot width). .

  According to the second embodiment, in addition to the same effects as those of the first embodiment, the following effects can be achieved. In addition to the time slot width of the own node and the number of received impulse signals, the phase shift destination is determined using the received width of the data signal, so even if there are many other nodes that receive only the impulse signal, It is possible to prevent the transmission / reception efficiency of the data signal from being deteriorated due to the phase shift.

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

  In the third embodiment, when it is determined that the time slot allocation width of the own node is smaller than when the time slot allocation is evenly allocated, a configuration and method for detecting a position where the time slot width is wide and shifting the phase are as follows: This is different from the first and second embodiments.

  FIG. 9 is a block diagram illustrating an internal configuration of a node according to the third embodiment. The same reference numerals are given to the same or corresponding parts as those in FIG. 1 according to the first embodiment.

  The node of the third embodiment has a phase shift width holding means 19 in addition to the node configuration of the first embodiment, and the time slot width measuring means 16 measures by having this phase shift width holding means 19. The target to change is also changing.

  The phase shift width holding means 19 has a function of storing a predetermined phase shift width (not limited to a fixed one) for phase shift control. The time slot width measuring means 16 of the third embodiment measures only the time slot width of the own node.

  Also in the third embodiment, the necessity for expanding the time slot width is determined in the same manner as in the first and second embodiments. That is, it is determined whether or not to control the phase shift.

  If it is determined that the phase shift control is to be performed, the phase shift width is input from the phase shift width holding unit 19 to the communication timing calculation unit 12 after the transmission of the self impulse signal, and the communication timing calculation unit 12 An impulse signal is transmitted when the phase shift width has elapsed.

  Due to the transmission of the impulse signal forcibly changing the phase from its own node, the transition is made to the transient state, the interaction between the nodes is executed, and the transmission of the data signal is resumed in the steady state again. Is done.

  Even when the phase is forcibly moved by the phase shift width and then the steady state is reached again, if the allocated time slot width of the own node is small, the phase shift control is further performed. Such phase shift control for each phase shift width is repeated so as to escape from a position where the allocated time slot width is small.

  Here, the phase shift width is not limited to a fixed one. For example, the phase shift width may be changed according to the number of nodes, such as increasing the phase shift width when the number of nodes is small and decreasing the phase shift width when the number of nodes is large.

  According to the third embodiment, in addition to the adjustment effect of the allocated time slot width similar to the first and second embodiments, the following effects can be obtained. Until the above-described embodiment, it is determined to which position the phase is shifted. Therefore, after measuring the time slot width of all nodes for one period of natural vibration, the phase shift destination is determined. However, in the third embodiment, since the phase shift width is determined in advance and stored in the phase shift width holding means 19, the phase shift control is started when the subsequent impulse signal is received. be able to.

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

  The fourth embodiment is characterized by a method that can easily determine whether or not the phase shift operation is started in another node, in other words, a steady state determination method related to the phase shift operation. The technical idea of the fourth embodiment can be combined with any of the technical ideas of the first to third embodiments described above.

  FIG. 10 is a block diagram illustrating an internal configuration of a node according to the fourth embodiment. The same reference numerals are given to the same or corresponding parts as those in FIG. 1 according to the first embodiment.

  The node according to the fourth embodiment includes impulse signal modulation means 20 in addition to the node configuration according to the first embodiment. The impulse signal modulation means 20 has a function of applying positive or negative modulation to the impulse signal based on the time slot width of the own node.

  Also in the fourth embodiment, the necessity for expanding the time slot width is determined in the same manner as the above-described embodiment. That is, it is determined whether or not to control the phase shift.

  If it is determined that the phase shift is not performed, the impulse signal modulation unit 20 applies negative modulation to the impulse signal. If it is determined that the phase shift is performed, the impulse signal modulation unit 20 determines that the impulse signal is positive. Transmit with modulation.

  In each other node, the modulation method of the impulse signal received by the impulse signal receiving means 11 is determined. If positive modulation is applied, it is determined that the transmission source node performs phase shift, and The transmission of the data signal is stopped. When the received impulse signal is negatively modulated, the same operation as that performed when the impulse signal is received in the above-described embodiment is executed. The node that transmitted the positive impulse signal performs a phase shift, interacts again, and enters a steady state. Each node starts transmitting a data signal if it is determined to be in a steady state.

  Note that whether the modulation is positive or negative may be determined from the following viewpoints. First, an interval from reception of a subsequent impulse signal to the own impulse signal, that is, a time slot allocation width of the own node is measured. When the time slot allocation width of the own node is TSa and the time slot width when TSb is assigned equally to the number of nodes as viewed from the own node is TSb, if the value of TSa is smaller, the impulse signal is positively modulated. If TSa has a larger value, the impulse signal is negatively modulated and transmitted.

  According to the fourth embodiment, in addition to the adjustment effect of the allocated time slot width similar to the first to third embodiments, the following effects can be achieved. Information on whether the time slot width allocated to the own node is larger or smaller than when the time slot width is allocated uniformly, that is, whether to start the phase shift control is transmitted on the impulse signal. By determining the modulation method of the received impulse signal, it is possible to determine whether or not the other node is in a steady state.

(E) Other Embodiments In the above embodiments, the time slot width is increased when the assigned time slot width is small. Conversely, when the assigned time slot width is large, You may make it narrow the time slot width of a node. For example, in the example of FIG. 5A, the node N9 can narrow the time slot width of its own node by shifting the impulse transmission phase <9> so far to the right. For example, it can be applied when it is known that the entire time slot width period allocated to the own node is not used for data signal transmission, depending on the difference between the allocated time slot width and the period necessary for data signal transmission. , Narrow the time slot width of its own node.

  In each of the above embodiments, the phase is shifted based on the assigned time slot width after becoming a steady state, but there is a change in the number of neighboring nodes such as when a node is newly added, When the interaction needs to be redone, the phase may be shifted based on the assigned time slot width at this timing.

  The present invention can be applied not only when the communication path is a wireless communication path but also when the communication path is a wired communication path.

  In addition to the above, various modifications can be made to the present invention. For example, various modifications applicable to the present invention are described in Japanese Patent Application No. 2003-328530 and the drawings.

It is a functional block diagram which shows the internal structure of the node of 1st Embodiment. It is a block diagram which shows the example of arrangement | positioning of the node of the communication system of 1st Embodiment. It is explanatory drawing (1) of the tuning between nodes in the communication system of 1st Embodiment. It is explanatory drawing (2) of the tuning between nodes in the communication system of 1st Embodiment. It is explanatory drawing which shows the example of a change of the time slot width before and behind the phase shift of 1st Embodiment. It is explanatory drawing which shows the content of the phase signal before and behind the phase shift of 1st Embodiment. It is a functional block diagram which shows the internal structure of the node of 2nd Embodiment. It is explanatory drawing of the content hold | maintained of the neighborhood node information holding means of 2nd Embodiment. It is a functional block diagram which shows the internal structure of the node of 3rd Embodiment. It is a functional block diagram which shows the internal structure of the node of 4th Embodiment.

Explanation of symbols

N1 to N16 ... nodes, 11 ... impulse signal receiving means, 12 ... communication timing calculating means, 13 ... impulse signal transmitting means, 14 ... tuning determination means, 15 ... data communication means, 16 ... time slot width measuring means, 17 ... angular velocity Change means, 18 ... neighboring node information holding means, 19 ... phase shift width holding means, 20 ... impulse signal modulation means.

Claims (9)

A communication timing control device provided in each of a plurality of nodes constituting a communication system,
With receive state variable signal indicating the operation timing of another node, a state variable signal communication means for transmitting a state variable signal indicating the operation timing of the own node intermittently,
Based on the state variable signal and the basic speed information of the transition from the other nodes that received the above state variable signal communication unit transitions the operation timing of the own node, the state variable signal from the local node that reflects this transition Timing determination means for recognizing a time slot in which one or a plurality of other nodes in the vicinity of which the node and the state variable signal reach can transmit data,
Data transmission means for transmitting a data signal for each periodic time slot determined by the operation timing of the own node;
Data receiving means for receiving data signals from other nodes;
Time slot width change determination means for determining whether or not the time slot width of the own node can be changed, and when the change of the time slot width of the own node becomes necessary, the operation timing of the own node in the timing determining means is forcibly A communication timing control device comprising: an operation timing shift means for shifting.   The time slot width change determination means includes the time slot width of the own node and the time slot width of the own node when it is assumed that the state variable signal is equally allocated to all other nodes and the own node that reach the own node. 2. The communication timing control apparatus according to claim 1, wherein whether or not the time slot width of the own node can be changed is determined based on the difference amount.   The operation timing shift means forcibly shifts the operation timing of the own node to a timing in a time slot of another node having the maximum time slot width recognized by the timing determination means. Or the communication timing control device according to 2;   The operation timing shift means includes a local node at a timing in the time slot of the other node having the maximum time slot width recognized by the timing determination means in the time slot of the other node where the data signal does not reach the own node. The communication timing control apparatus according to claim 1 or 2, wherein the operation timing is forcibly shifted.   The communication timing control apparatus according to claim 1 or 2, wherein the operation timing shift means forcibly shifts the operation timing of the own node by a predetermined shift amount. When the operation timing shift means performs a shift operation, a transmission state variable signal switching means for switching a state variable signal transmitted from the own node to a special state variable signal indicating that,
Transmission stop control means for stopping the transmission operation from the data transmission means until the transition state of the timing determination means can be determined as a steady state when a special state variable signal is given from another node. The communication timing control device according to any one of claims 1 to 5, wherein   A node comprising the communication timing control device according to claim 1.   A communication system comprising a plurality of nodes according to claim 7. A communication timing control method executed by each of a plurality of nodes constituting a communication system,
With receive state variable signal indicating the operation timing of another node, a state variable signal communication step of transmitting intermittently the state variable signal indicating the operation timing of the own node,
Based on the state variable signal and the basic speed information of the transition from the other nodes received by the state variable signal communication step transitions the operation timing of the own node, the state variable signal from the local node that reflects this transition A timing determination step for recognizing a time slot in which data can be transmitted to one or a plurality of other nodes in the vicinity where the node and the state variable signal reach,
A data transmission step of transmitting a data signal for each periodic time slot determined by the operation timing of the own node;
A data receiving process for receiving data signals from other nodes;
When the time slot width change determination step for determining whether or not the time slot width of the own node can be changed, and when the time slot width of the own node needs to be changed, the operation timing of the own node in the above timing determination step is forcibly A communication timing control method comprising: an operation timing shift step of shifting.

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