JP4232715B2 - Transmission medium access control apparatus, transmission medium access control method, and transmission medium access control program - Google Patents

Description

  The present invention relates to a transmission medium access control apparatus, a transmission medium access control method, and a transmission medium access control program. For example, as in an ad hoc network, an equal distributed communication in which a node relays data transmitted from another node. It is suitable for application to a system or the like.

  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 method, when the number of nodes (number of channels) increases, the number of channels that can be simultaneously communicated decreases due to frequent collisions and the like.

In the TDMA system, different time slots are assigned to each node, and each node transmits data in the time slot assigned to itself. The TDMA system is easier to increase the number of channels that can be simultaneously communicated than 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

  By the way, it is not always easy to realize TDMA in an equally distributed environment in which each node does not receive control from a special node such as the management node described above and operates autonomously.

  In addition, when there is a possibility that each node has mobility, the combination of nodes that perform multiplex communication by TDMA, the time slot of each node, etc. can change dynamically. In order to achieve this, each node needs to constantly receive a control signal (impulse signal) indicating the time slot allocation status and the like.

  However, receiving the control signal at all times is disadvantageous in terms of power saving at each node.

  For this reason, a configuration in which each node intermittently receives a control signal may be considered, but if a period occurs in which all nodes in the vicinity (range where the control signal reaches) do not receive the control signal at the same time, the new node will be in the vicinity A new problem arises that it may not be possible to cope with the movement of a node, such as when it appears on the screen. If other neighboring nodes cannot detect that a new node has appeared in the vicinity, time slot assignment to the new node cannot be performed normally, for example, communication between the new node and other neighboring nodes cannot be performed, or the new node There is a possibility that communication between other nodes in the vicinity may be hindered by a control signal transmitted by, so that efficiency is low and reliability is low.

In order to solve such a problem, the first aspect of the present invention executes access control for a transmission medium by allowing the own node to access the transmission medium using any of a plurality of periodically circulated time slots. a transmission medium access controller, the transmission operation of transmitting (1) together with the receiving operation of receiving the state variable signal indicating the operation timing of another node, the state variable signal indicating the operation timing of the own node intermittently a state variable signal communication unit that executes, (2) based on the state variable signals from other nodes to which the state variable signal communication unit has received, shifts the operating timing of the own node, the local node that reflects this transition The state variable signal is generated and given to the state variable signal communication unit, and one or a plurality of other nodes in the vicinity to which the state variable signal reaches is a data signal. A timing determination unit for recognizing a time slot that can be transmitted; (3) a data transmission unit that periodically transmits a data signal for each time slot determined by the operation timing of the own node; and (4) a data signal from another node. (5) When the operation state is in a predetermined steady state, a predetermined monitoring period is set at a predetermined phase position determined on the basis of the time slot of the own node on the cycle. A monitoring period setting unit; and (6) when in the steady state, in a period other than the monitoring period on the cycle, the reception operation by the state variable signal communication unit is stopped, and from other nodes during the monitoring period When the reception status of the state variable signal fluctuates, it is determined that the steady state has collapsed between the one or more other nodes in the vicinity, and a period other than the monitoring period on the period But, characterized in that a state variable signal reception operation control unit to perform a receiving operation to the state variable signal communication unit.

According to a second aspect of the present invention, there is provided a transmission medium access control method for performing access control on a transmission medium by allowing the own node to access the transmission medium using any one of a plurality of periodically circulated time slots. there are, (1) a state variable signal communication unit, the receive operation of receiving the state variable signal indicating the operation timing of another node, the transmission operation of transmitting a state variable signal indicating the operation timing of the own node intermittently is executed, (2) the timing determination unit, based on the state variable signals from other nodes to which the state variable signal communication unit has received, shifts the operating timing of the own node, the local node that reflects this transition The state variable signal is generated and given to the state variable signal communication unit, and one or a plurality of other nodes in the vicinity to which the state variable signal reaches is a data signal. Recognizing a time slot that can be transmitted, (3) the data transmission unit periodically transmits a data signal for each time slot determined by the operation timing of the own node, and (4) the data reception unit is transmitted from another node. (5) when the operation state is in a predetermined steady state, the monitoring period setting unit performs predetermined monitoring at a predetermined phase position determined on the basis of the time slot of the own node during the period. (6) When the state variable signal reception operation control unit is in the steady state, the state variable signal reception operation control unit stops the reception operation by the state variable signal communication unit in a period other than the monitoring period on the cycle. If the reception state of the state variable signal from another node during the monitoring period fluctuates, it is determined that the steady state has collapsed between the one or more other nodes in the vicinity, and the period Even in a period other than the monitoring period, characterized in that to perform the receiving operation to the state variable signal communication unit.

Further, according to the third aspect of the present invention, there is provided a transmission medium access control program for performing access control on a transmission medium by causing the own node to access the transmission medium using any one of a plurality of periodically circulated time slots. there, the computer, (1) a state where the receive operation of receiving the state variable signal indicating the operation timing of another node, to perform a transmission operation for transmitting the state variable signal indicating the operation timing of the own node intermittently a variable signal communication function, (2) the state variable signal communication function based on the state variable signals from other nodes received by the transitions the operation timing of the own node, the state of the local node that reflects this transition A variable signal is generated and given to the state variable signal communication function, and one or a plurality of other nodes near the node and the state variable signal reach A timing determination function for recognizing a time slot capable of transmitting a data signal, (3) a data transmission function for periodically transmitting a data signal for each time slot determined by the operation timing of the own node, and (4) another node (5) when the operation state is in a predetermined steady state, and when the operation state is in a predetermined steady state, a predetermined monitoring is performed at a predetermined phase position determined on the basis of the time slot of the own node. A monitoring period setting function for setting a period; and (6) when in the steady state, in a period other than the monitoring period on the period, the reception operation by the state variable signal communication function is stopped, When the reception status of the state variable signal from another node fluctuates, it is determined that the steady state has collapsed between the one or more other nodes in the vicinity, and the period Even in a period other than the monitoring period, characterized in that to realize the state variable signal reception operation control function to perform the receiving operation to the state variable signal communication function.

  According to the present invention, TDMA can be realized in an equally distributed environment, and efficiency and reliability can be improved.

(A) Embodiments Embodiments of a transmission medium access control device, a transmission medium access control method, and a transmission medium access control program according to the present invention will be described below.

  This embodiment proposes a new communication protocol. This communication protocol is a kind of TDMA.

(A-1) Configuration of the First Embodiment FIG. 9 shows an example of the overall configuration of the communication system 10 according to the present embodiment.

  In FIG. 9, the communication system 10 includes nodes A to J and X.

  Each node has a transmission function for transmitting impulse signals and data signals, a reception function for receiving impulse signals and data signals transmitted from other nodes, a relay function for transmitting data signals transmitted from other nodes to other nodes, etc. Have the same function. The impulse signal is a control signal (timing signal) used when each node transmits the phase position of its own time slot to other nodes. The data signal is user data used in a predetermined communication application.

  As a result, each node can configure an ad hoc network.

  The time slot is used to limit the transmission right of each node. Basically, the reception right is always held by all nodes.

  In FIG. 9, wireless such as the node A relays the data signal DE transmitted by the node E to the node F, or the node A relays the data signal DD transmitted by the node D to the node B. Communication is taking place.

  In addition, since there is a physical limit (cover area) in the range in which the radio signal such as the impulse signal and the data signal reaches, each node has only the impulse signal and data in other nodes existing within its own cover area. A signal can be delivered. As will be described later, it is desirable that the coverage area of the impulse signal is larger than the coverage area of the data signal.

  Each of the nodes A to F and X may have mobility, such as a notebook personal computer, but may not have mobility.

  In the example of FIG. 9, since the nodes A to F belong to the coverage area of the impulse signal and the data signal, the impulse signal and the data signal can be exchanged.

  In the following, mainly, when the node X does not initially exist and the impulse signal and the data signal are exchanged between the existing nodes A to F, the result of the new node X appearing at the position shown in FIG. The explanation will be made on the assumption that the steady state described will collapse.

  In order to simplify the explanation, nodes other than the nodes A to F and X (for example, the nodes G to J) are not basically mentioned, but actually, communication of data signals other than those shown in FIG. Of course, impulse communication, for example, the data signal DD transmitted from the node D and delivered to the node B via the node A may be further relayed to the node H by the node B and the like.

  In the following description, FIG. 10 is used as necessary. Each node N1 to N16 in FIG. 10 is a node having the same function as the node A or the like.

  In FIG. 10, solid line circles centered on the nodes of interest N1 and N2 indicate the range in which the nodes N1 and N2 can receive the impulse signal transmitted by other nodes (coverage area of the impulse signal). In the example of FIG. 10, 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 (data signal cover area) in which the other nodes and the target nodes N1 and N2 can exchange data signals. In the example of FIG. 10, 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.

  In this embodiment, as shown in FIG. 10, even if there is a bias in the arrangement of the nodes, the time slots in each node can be allocated as evenly as possible (including the case of reassignment).

  The internal configuration of the node A is, for example, as shown in FIG. The internal configurations of the other nodes B to F and X and the nodes N1 to N16 are the same as this.

(A-1-1) Internal Configuration Example of Node In FIG. 1, the node A includes an impulse signal reception unit 11, a communication timing calculation unit 12, an impulse signal transmission unit 13, a tuning determination unit 14, and a data signal. A communication unit 15, a time slot width measurement unit 16, an angular velocity change unit 17, a node position detection unit 18, an impulse reception width storage unit 19, and an on / off control unit 20 are provided.

  Among these, the impulse signal receiving means 11 receives an impulse signal (not including destination information) transmitted by a nearby node (for example, another node existing in the coverage area of the impulse signal related to the own node A). It is. The impulse signal has, for example, an impulse shape such as a Gaussian distribution shape. The impulse signal receiving unit 11 gives the received impulse signal itself, a waveform-shaped signal thereof, 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 unit 12 forms and outputs a phase signal that defines the communication timing at the node A based on the signal given from the impulse signal reception unit 11.

Here, assuming that the node A is a node i in order to generalize the node A and the phase value of the phase signal at time t is θi (t), the communication timing calculation means 12 can change the amount of change shown in the equation (1). The phase signal θi (t) is changed step by step. 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 neighboring 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 unit 12 will be described in detail with reference to FIGS. 11 and 12 show a relationship formed between a target node (own node) i and a neighboring node (other node) j when attention is paid to a certain node i, that is, each nonlinear vibration rhythm. The phase relationship between them changes with time.

  FIG. 11 shows a case where there is one neighboring node j for the node of interest i. In FIG. 11, the motion of two mass points rotating on a circle represents a non-linear vibration rhythm corresponding to the node of interest and 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, as time elapses, the state (transient state) shown in FIG. 11B is changed to a steady state in which the phase difference between the two mass points is almost π as shown in FIG. 11C.

  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 (phase interaction) based on the transmission / reception of an impulse signal occurs between nodes, these mass points change their angular velocities (slow and steep), and as a result, a steady state that maintains an appropriate phase relationship To reach. 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. 12 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 3 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.

  11 and 12 show the case where there are one or two other nodes that transmit and receive the impulse signal in the vicinity of the node of interest. However, as illustrated in FIG. 9 and FIG. The arrangement relationship of the nodes is more complicated than the cases assumed in FIG. 11 and FIG.

  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 signal 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. 11, 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 the 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 FIG. 11B and FIG. 12B) or It is determined which state is “steady state” (see FIG. 11C and FIG. 12C). 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 observed value β of the phase signal θi (t), the difference (phase difference) between adjacent values 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) in the phase difference Δ in the successive periods γ1 = Δ1 (τ + 1) −Δ1 (Τ), γ2 = Δ2 (τ + 1) −Δ2 (τ),..., ΓN = ΔN (τ + 1) −ΔN (τ) are calculated. Here, τ indicates a certain cycle of the phase signal θi (t), and τ + 1 indicates the next cycle of the phase signal θi (t).

  (D) When the above-described 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 signal communication means 15.

  The data signal communication means 15 has a function of transmitting and receiving a data signal therein. As a result, the data signal communication means 15 can receive a data signal from another node and transmit a data signal that is the transmission source of the data signal and a data signal that is relayed by the data signal communication unit 15.

  The data signal communication means 15 performs data transmission (data signal transmission) in a fixed manner assigned by a time slot (system (corresponding to the management node) described later) when the tuning determination signal indicates “steady state”. 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. 11C, 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. If 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 and the data signal or the like does not collide. 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 calculation means 12, the impulse signal transmission means 13, the tuning determination means 14 and the data signal communication means 15 described above (the width of the time slot is as small as possible). For equality), time slot width measuring means 16 and angular velocity changing means 17 are 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.

The functions of the time slot width measuring unit 16 and the angular velocity changing unit 17 will be described in more detail with reference to FIGS.
FIGS. 13A and 13B show the time slot allocation 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 4 (FIG. 13A) or 12 (FIG. 13B), and time slots are allocated.

  In FIG. 13, the time slots given “N1” to “N12” 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 phase interaction of neighboring nodes, and as shown in FIG. have. In order to correct such an imbalance of allocation as much as possible (in order to review the assigned 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 time slot reassignment operation is performed in two stages: (S1) determination of necessity for expanding the time slot width and (S2) phase shift control.

(S1) Determination of necessity of time slot width expansion The time slot width measuring 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. The number of nodes in the impulse signal receivable range (in the impulse signal cover area) is examined. For example, the time slot width measuring means 16 of the node N1 receives one impulse impulse from the transmission of the self impulse signal at the timing <1> in FIG. 13A until the next transmission of the self impulse signal. Count the number of signals and check the number of nodes in the coverage area of the impulse signal. Thereby, the time slot width measuring means 16 of the node N1 obtains the number of nodes “4”. Further, the time slot width measuring means 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 causes the time between <1> and <2>, the time between <1> and <3>, and <1> and <9 in FIG. By measuring the time between> and arranging 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 in FIG. 13A, the time slot widths of the nodes N1 are smaller than those assigned evenly, so that the angular velocity changing unit 17 determines to perform phase shift control.

  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 (PA) and conditions (PB) are satisfied, and phase shift control is performed when a plurality of conditions are satisfied. Also good.

Condition (PA): Time slot width allocated to own node <maximum time slot width / 2
Condition (PB): Sum of time slots before and after own impulse signal <maximum time slot width (S2) Phase shift control When angular velocity changing means 17 receives an impulse signal defining the end of the time slot of its own node (FIG. 13 (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. 13A) And the phase difference θi (t + 1) −θi (t) is held. Further, the angular velocity changing means 17 examines the phase difference θi (t + 2) −θi (t + 1) at the time of receiving the next impulse signal (<9> in FIG. 13A), and if this phase difference is large, the impulse The signal phase θi (t + 1) and phase difference θi (t + 2) −θi (t + 1) 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 position of the held phase + (1/2 of the phase difference). From the viewpoint of the node N1, the time slot assigned to the node N3 is the largest (as seen from the retained phase difference), so that the phase of the node N1 is shifted to this position as shown in FIG. The transmission of the impulse signal is started.

  FIGS. 13C and 13D show the time slot widths as 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. At this time, the state shown in FIG. 14A is changed to the state shown in FIG. 14B on FIG.

  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.

  Actually, as in this example, it is often difficult to assign time slots to each node completely evenly (assigning a time slot of the same time width to each node) depending on the arrangement situation of the nodes, In the following, for simplicity of explanation, it is assumed that time slots having an equal time width are basically allocated to each node in a steady state.

  The node position detection means 18 acquires information regarding the phase position in one cycle of the time slot with respect to the time slot of each node existing in the cover area of the node A. Specifically, detecting the phase difference between the time slot of the own node A and another node, or the time interval between the transmission time of the impulse signal by the own node A and the transmission time of the impulse signal by the other node (for example, B), etc. Thus, information on the phase position of each node is acquired.

  The phase position of each node (corresponding to the timing at which each node transmits an impulse signal or the time slot of each node) in one cycle of the time slot is as shown in FIG. 4, and A → B → C →. Assuming that the time slot of each node arrives in circulation in sequence, the node A detects that the node having the time slot immediately before its own node in the one cycle is F by the node position detection means 18. Then, the time width of the time slot FTS of the node F can be detected. Similarly, the node having the time slot immediately after the self node in the one cycle is B, and the time width of the time slot ATS of the self node A that is the period up to the time slot BTS of the node B is detected. be able to.

  The impulse reception width storage means 19 is a period (impulse signal reception operation period) in which the node A performs an impulse signal reception operation in the one period in a steady state based on the information acquired by the node position detection means 18. Is stored. Impulse signal reception period information RT1 indicating.

  The impulse signal receiving operation period can be determined in various ways, but in order to reliably detect the appearance of the new node X, the impulse signal receiving operation periods of all the existing nodes A to F in the vicinity are overlapped. It is desirable that the entire period of one cycle can be covered without omission. However, in a wireless transmission path, due to a transmission error or the like, it is possible that another node cannot receive normally even though an impulse signal is transmitted from any node in the coverage area. In order to detect the appearance of X reliably and promptly, it is preferable that the entire period on one cycle is covered more than twice.

  On the other hand, from the viewpoint of power saving or the like, it is advantageous that the period during which each existing node (for example, A) performs an impulse signal reception operation is as short as possible. If the period during which the impulse signal is received is shortened, the number of received signals (impulse signal, noise, etc.) can be reduced, and the period for processing the received impulse signal can be shortened. It is also possible to save processing capacity such as a CPU (central processing unit) that does not.

  In the present embodiment, as an example, in FIG. 4, RA1, RA2, RA3, and RA4 are set as periods in which the node A performs the impulse signal reception operation. Of these, the period (direct detection period) RA1 is the longest and covers the entire period of the time slots FTS and ATS. In addition, this period RA1 is longer by ε in the front and rear directions (F direction and B direction as viewed from A) than the period in which FTS and ATS are added. This ε is the same as the above-mentioned minute parameter (threshold value), but here has a meaning as an allowable value of an error related to the phase difference in one period. The time slot ATS is a time slot for the node A. In a steady state, the node A transmits an impulse signal and a data signal only in the time slot ATS.

  Similarly, time slot BTS is a time slot for node B, time slot CTS is a time slot for node C, time slot DTS is a time slot for node D, and time slot ETS is for node E. The time slot FTS is a time slot for the node F. In steady state, each node B-F transmits an impulse signal and a data signal only within its own time slot.

  If all the nodes A to F and X use the same frequency for transmission of the impulse signal, the node A transmits another node (for example, X) when the node A itself transmits the impulse signal. The period RA1 is actually interrupted once at the phase position of A (the timing at which the node A transmits the impulse signal), and the first half period RA11 before A and A The latter half period RA12 is composed of two periods. In the present embodiment, it is mainly assumed that the nodes A to F and X use the same frequency for transmission of impulse signals.

  The impulse signal reception period information RT1 for defining the first half period RA11 and the second half period RA12 can be summarized in the form of a table shown in FIG. 3, for example.

Table 3, the node of the time slots constituting one period as shown in FIG. 4 is six, impulse signal transmission of another node F to send previously impulse signal by a time T _F -T _A than the self node A phase difference of the phase position of the impulse signal transmission time of the time of the phase position and the own node a (prior impulse _{position), θ F (T F -T} a) is that, by the time _T B -T _a than the self node a The phase difference (subsequent impulse position) between the phase position of the impulse signal transmission time of the other node B that transmits the impulse signal later and the phase position of the impulse signal transmission time of its own node A is θ _B (T _B −T _A ). It is shown that.

  As executed by the time slot width measuring unit 16, the node position detecting unit 18 receives 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 in a steady state. By counting the number of nodes in the coverage area of the impulse signal, it can be identified that there are six nodes in the time slot constituting one period.

In addition, while shifting the phase position of the own node A from A → B → C →. When the node A transmits an impulse signal as the impulse position, the contents stored in the preceding impulse position and the contents stored in the subsequent impulse position are determined and saved, so that θ in FIG. _{F (T F} -T _a) and θ _{B (T B} -T _a) is obtained.

Instead of such a phase difference, the time interval (in this _case, T F -T _A and _T B -T _A) may be stored only.

  The period (indirect detection period) RA2 is set to a C phase position (timing at which the node C transmits an impulse signal) in FIG. 4, and before and after the C phase position (from the C perspective, the B direction and the D direction). ) Has a time width of ε.

  Similarly, the period (indirect detection period) RA3 is set to the D phase position (timing at which the node D transmits the impulse signal) in FIG. 4, and before and after the D phase position (as viewed from D, in the C direction). E period) has a time width of ε, and the period (indirect detection period) RA4 is set to the E phase position (the timing at which the node E transmits the impulse signal) in FIG. It has a time width of ε in the front and rear direction (D direction and F direction as viewed from E).

  The period RA1 can be used to check whether the impulse signal transmitted from the node F and the impulse signal transmitted from the node B are transmitted at the original phase position, and the new node X appears in the vicinity. When an impulse signal is transmitted within the period RA1, it can also be used to directly detect (directly detect) the impulse signal.

  For example, when the node B receives an impulse signal transmitted from the new node X by direct detection, the phase position at which the node B transmits the impulse signal is changed by the phase interaction such as the repulsion (this change width is Detecting that the impulse signal transmitted by the node B is not transmitted at the original phase position indirectly detects that the new node X has transmitted the impulse signal (indirectly). This period RA1 can also be used for indirect detection.

  However, since the period during which the impulse signals from the existing nodes F and B are not transmitted is long in the period RA1, it can be said that the period RA1 is mainly a period for direct detection. In the case where it is not checked whether or not the impulse signal transmitted by the existing nodes F and B within the period RA1 is transmitted at the original phase position (for example, the impulse received simply during that period (for example, RA11)). In the case where only the number of signals is inspected), the period RA1 is purely a period for direct detection.

  The period RA2 can be used to check whether or not the impulse signal transmitted from the node C is transmitted at the original phase position, and the new node X appears in the vicinity, and the impulse signal is transmitted within the period RA2. If sent, it can also be used to detect it directly.

  Similarly, the period RA3 can be used to confirm whether or not the impulse signal transmitted by the node D is transmitted at the original phase position, and the new node X appears in the vicinity and the period RA3 falls within the period RA3. When the impulse signal is transmitted, it can be used to directly detect the impulse signal, and the period RA4 is used to confirm whether or not the impulse signal transmitted by the node E is transmitted at the original phase position. In addition to this, when the new node X appears in the vicinity and transmits an impulse signal within the period RA4, it can also be used to directly detect it.

  Here, detecting that the impulse signal transmitted by the node A itself and the existing nodes other than the nodes F and B (for example, D) is not transmitted at the original phase position is indirectly detected by the new node X. This is the same as the indirect detection for detecting the transmission of the impulse signal. The impulse signal transmitted by the existing node D performs a new phase interaction such as the repulsion when the steady state collapses by directly detecting the impulse signal transmitted by the new node X by the existing node D or the like. This is because transmission is not performed at the original phase position.

  The phase position at which the new node X transmits the impulse signal cannot be predicted, and may be transmitted during the period RA2, for example. However, the periods RA2, RA3, and RA4 are mainly periods for indirect detection because the periods other than the period during which the original impulse signal is transmitted by the existing node are short. If it is not checked whether the new node X has transmitted an impulse signal within the periods RA2, RA3, RA4, the periods RA2, RA3, RA4 are purely periods for indirect detection.

  The specification of an impulse signal is a specification that can absolutely identify the transmission source, although it depends on the implementation whether the impulse signal is a signal (for example, whether or not it includes a transmission source address that identifies the transmission source node). In this case, an impulse signal transmitted from a node other than the existing nodes A to F may be regarded as transmitted by the new node X. On the other hand, when the specification is such that the transmission source cannot be identified, the number of impulse signals received within one period (for example, one such as RA2 or RA11) is simply counted, and two or more When the impulse signal is received, the new node X may be regarded as having transmitted the impulse signal. Thereby, the appearance of the new node X can be directly detected by a simple inspection. In the following, it is mainly assumed that the impulse signal does not include a transmission source address.

  The on / off control means 20 switches the impulse signal reception means 11 on or off based on the impulse signal reception period information RT1.

  Specifically, in the example of FIG. 4, during one period, the impulse signal receiving means 11 is turned on during the periods RA11, RA12, RA2, RA3, and RA4, and is turned off during the other periods.

  The operation of the present embodiment having the above configuration will be described below.

(A-2) Operation of First Embodiment In the node arrangement shown in FIG. 9, the time of each node A to F in a steady state in which time slots having an equal time width are allocated to the neighboring six nodes A to F The phase positions where the slots ATS to FTS start (phase positions at which the nodes A to F transmit impulse signals) circulate in the order of A → B → C →... → F, as shown in FIG. And

  At this time, in the node A, the node position detection means 18 or the like corresponds to the impulse signal reception period information RT1 for defining the first half period RA11 and the second half period RA12 which are part of the impulse signal reception operation period. The table shown in FIG. 3 is obtained. In addition to this table, information defining the periods RA2 to RA4 is obtained as impulse signal reception period information RT1 indicating the remainder of the impulse signal reception operation period. The impulse signal reception period information RT1 is stored in the impulse signal width storage means 19.

  Subsequently, in the node A, the on / off control means 20 performs on / off control of the impulse signal reception means 11 based on the impulse signal reception period information RT1. Thereby, only during the periods RA11, RA12, RA2, RA3, and RA4 shown in FIG. 4, the impulse signal receiving means 11 is turned on and the impulse signal receiving operation is performed.

  On the other hand, in one period shown in FIG. 4, the impulse signal receiving means 11 is turned off during the periods other than these periods RA11, RA12, RA2, RA3, and RA4, and the impulse signal receiving operation is not performed. As a result, power consumption and processing capacity in the node A can be saved and efficiency can be increased.

  The nodes B to F in the vicinity other than the node A also set the impulse signal receiving operation period based on the phase position at which the nodes B to F themselves transmit the impulse signal, so that the impulse signal receiving operation of each of the nodes A to F is performed. The period is set with a phase shifted by one period in FIG. 4, and the entire period of one period can be covered in multiple.

  For example, the direct detection period RB1 of the node B corresponding to the direct detection period RA1 is a period from the phase position of B to the phase position of C, with the phase position of B as the center, as shown in FIG. Therefore, between A and B, it overlaps with the direct detection period PA1.

  In addition to the direct detection period and indirect detection period of other nodes C to F not shown in FIG. 4, the indirect detection period of node B is also set in one actual cycle. The entire period is covered in multiple.

  Although there is a possibility that the new node X transmits an impulse signal at any phase position on one cycle, it is transmitted between B and C in the example of FIG. In this case, the impulse signal transmitted by the new node X is first directly detected by the node B corresponding to the direct detection period PB1 and the node C corresponding to the direct detection period PC1.

  When the nodes B and C change the phase position of the impulse signal transmitted by themselves according to this direct detection, the change is also detected at the node A and the indirect detection is performed. Similarly, other nodes D, E, and F perform indirect detection, so that all nodes A to F in the vicinity eventually recognize the collapse of the steady state. Recognizing the collapse of the steady state, each of the existing nodes A to F performs the receiving operation for receiving the impulse signal in the entire period of one cycle, so that all the existing nodes A to F in the vicinity are new. The impulse signal transmitted from the node X can be directly received, and phase interaction is performed by seven nodes including the new node X. Thus, a new steady state is formed by seven nodes (A to F and X) through the transient state. One cycle of this steady state is, for example, as shown in FIG. In this steady state, since a time slot is also assigned to the node X, the node X naturally transmits a data signal to another nearby node (for example, A) or receives a data signal from another nearby node. It is also possible.

  Further, since the node X transmits the impulse signal and the data signal only within the time slot allocated to itself, the node X does not disturb the communication of the other nearby nodes A to F.

  In the present embodiment, since the entire period of one cycle shown in FIG. 4 is covered at least twice by the period for direct detection of each of the existing nodes A to F, at which phase position the new node X outputs the impulse signal. Even if it is transmitted, it can be reliably detected. For example, at the time of direct detection by the nodes B and C described above, an impulse signal transmitted by the new node X cannot be normally received by either the node B or C due to a transmission error due to an unexpected noise or the like. Even in such a case, if any one of the nodes (for example, B) can perform direct detection, the other six nodes A and C to F can perform steady detection by performing indirect detection. Recognize the collapse and form a new steady state with seven nodes AF and X. Therefore, in this embodiment, the impulse signal transmitted by the new node X cannot be detected, and there is almost no possibility that it cannot cope with the appearance of the new node X, and the reliability is extremely high.

  When the same frequency is used for the impulse signal and the data signal, the data transmitted and received between any existing nodes (for example, between nodes D and A) by the impulse signal transmitted by the new node X first. Although a transmission error may occur in a signal (for example, DD), since the appearance of a new node X is immediately detected by the existing nodes D and A due to the direct detection or indirect detection, it is transmitted immediately before detection. Alternatively, the received data signal DD can be easily subjected to retransmission control, and in this sense, it can be said that communication reliability is high.

  Since all nodes other than node A (including X) also have the same function as node A, for example, when a new node (eighth node) following new node X appears, the same process is performed. Through this, it is possible to form a new steady state with 8 nodes.

  Further, in an equally distributed environment, the existing nodes A to F may become new nodes, but even in such a case, it is possible to cope with the same operation as described above. It is natural.

(A-3) Effects of the First Embodiment According to the present embodiment, TDMA can be realized in an equally distributed environment, and efficiency and reliability can be improved.

(B) Second Embodiment Hereinafter, only differences between the present embodiment and the first embodiment will be described.

(B-1) Configuration and operation of the second embodiment The configuration is different from the first embodiment in terms of configuration only in respect of the internal configurations of the nodes A to F and X. Since the feature of the present embodiment is exhibited when a node behaves as the new node, the description will be focused on the node X.

  The internal configuration of the node X of this embodiment is as shown in FIG. 7, for example. The internal configurations of the other nodes A to F are the same as this.

  In FIG. 7, the node X 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 signal communication unit 15, a continuous impulse generating unit 21, Period detection means 22 and initial synchronization timing generation means 23 are provided.

  Among these, the functions of the constituent elements 11 to 18 given the same reference numerals as those in FIG. 1 are basically the same as those in the first embodiment, and thus detailed description thereof is omitted. Although not shown in FIG. 7, the node A of the present embodiment may include the time slot width measuring unit 16 and the angular velocity changing unit 17 having the same functions as those of the first embodiment. Of course.

  The continuous impulse generating means 21 transmits a continuous impulse signal to the impulse signal transmitting means 13 when the node X appears in the vicinity of the impulse signal cover area of the existing nodes A to F. It is something to make. Since this transmission is performed in order to increase the probability of the direct detection, it is desirable to perform at least a plurality of times in one cycle. However, in order to increase the probability of direct detection, the time interval between successive impulse signal transmissions The shorter the better, the better. Here, the time interval is preferably shorter than a predetermined minimum time width for the time slot (or a value smaller than that (for example, a time width that is ½ of the minimum time width)). However, if necessary, the time interval may not be the same throughout one period.

  The time width of the time slot allocated to each node tends to become shorter as the number of neighboring nodes increases. However, in actual implementation, a certain limit value (minimum value) is set for reducing the time width of the time slot. It is necessary to set, and there is a high possibility that the minimum time width exists.

  As described above, the time slot is for limiting the transmission right of each node. Basically, the reception right is always held by all the nodes, but in this embodiment, the impulse signal in the steady state is also maintained. Reception is limited to that which can be performed only during the impulse signal reception operation period as in the first embodiment. In the case of the present embodiment, even if the impulse signal reception operation period is set to a time width approximately equal to the minimum time width of the time slot, each of the existing existing nodes A to F in the vicinity detects the direct detection. Can be executed.

  FIG. 8 is an example in which the time interval of continuous impulse signal transmission is not the same throughout one period. Also in FIG. 8, since the time interval is sufficiently short, one impulse signal reception operation period (for example, RA1 , RD1), the impulse signal transmitted by the new node X is received by the existing node at least twice. Note that RD1 is a period for direct detection of the node D.

  The period detection means 22 detects a time during which the impulse signal is continuously transmitted at the time interval. Thereby, transmission of the impulse signal by the said time interval can be continued only for predetermined continuous transmission time CT1. The continuous transmission time CT1 may be determined in any way. For example, the continuous transmission time CT1 may be determined based on the time required for the mass point to rotate one period at the basic frequency ω. You may determine a long value, for example, 2 periods or more. This also increases the probability of the direct detection by nearby nodes A to F other than the node X.

  The initial cycle timing generation unit 23 determines a phase position when the node X first transmits an impulse signal in the vicinity. This phase position can be determined by various methods. For example, it may be determined randomly by generating a random number. Further, for example, in a steady state by the six nodes A to F before the appearance of the node X, a time slot that is not used for data signal transmission is detected, and the first impulse signal of the node X is detected at the phase position in the time slot. You may decide to send

  In the case of this embodiment, either the direct detection period or the indirect detection period (except for those used for purely indirect detection) is omitted, or the time width of the direct detection period or the indirect detection period is set to Even if it is shorter than the first embodiment, each of the existing nodes A to F is likely to be able to execute the direct detection with the same or higher probability as the first embodiment. Compared to the above, there is a high possibility that the power consumption and the processing capacity used by each of the existing nodes A to F in the vicinity to receive the impulse signal can be further saved.

(B-2) Effect of Second Embodiment According to the present embodiment, an effect equivalent to the effect of the first embodiment can be obtained.

  In addition, in the present embodiment, there is a high possibility that the power consumption and the processing capability used to receive the impulse signal transmitted by the new node (X) from each existing existing node (A to F) in the vicinity can be further saved.

(C) Other Embodiments In the first and second embodiments described above, the case where the number of neighboring existing nodes is mainly described has been described. However, the number of neighboring existing nodes may be smaller than six and many. Of course.

  Further, in FIG. 10, a circular cover area is shown, but it is natural that the shape of the cover area is not necessarily circular. The shape of the cover area is mainly determined by the directivity of the antenna mounted on each node and used for transmission and reception of radio signals (impulse signals and data signals).

  Furthermore, as described above, if different frequencies are used for the impulse signal and the data signal, or if different frequencies are used for the impulse signal transmitted by each node, the system configuration may be much easier. If the same frequency is used for the impulse signal and the data signal and the same frequency is used for the impulse signal transmitted by each node as in the first and second embodiments, limited frequency resources can be saved.

  In the second embodiment, the transmission of the continuous impulse signal is continued for the predetermined continuous transmission time CT1 at the time interval. However, the value of the continuous transmission time CT1 is a phase mutual value. You may make it change dynamically according to the progress of an effect | action, etc. For example, when at least one node (for example, A) among the six existing nodes A to F in the vicinity clearly recognizes the collapse of the steady state and starts a phase interaction toward the new steady state (this) Can be recognized from, for example, the fluctuation of the phase position of the impulse signal transmitted by the node (for example, A)), even if the node X does not reach the predetermined CT1, the impulse signal continues. You may make it stop typical transmission. Thereby, there is a possibility that the time until the formation of a new steady state by the seven nodes A to F and X including the node X can be further shortened.

  In the above description, the present invention is realized mainly in hardware, but the present invention can be realized in software.

It is the schematic which shows the internal structural example of the node used by 1st Embodiment. It is the schematic which shows 1 period of the time slot in 1st Embodiment. It is the schematic which shows an example of the impulse signal reception period information used in 1st Embodiment. It is the schematic which shows an example of the impulse signal receiving operation period used in 1st Embodiment. It is the schematic which shows 1 period of another time slot in 1st Embodiment. It is the schematic which shows another example of the impulse signal reception period information used in 1st Embodiment. It is the schematic which shows the internal structural example of the node used by 2nd Embodiment. It is the schematic which shows an example of the impulse signal transmission time performed in 2nd Embodiment. It is the schematic which shows the example of whole structure of the communication system concerning 1st and 2nd embodiment. It is the schematic which shows another whole structure example (arrangement example of a node) in the communication system concerning 1st Embodiment. It is explanatory drawing of the tuning between nodes in the communication system of 1st Embodiment. It is explanatory drawing 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.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Communication system, 11 ... Impulse signal reception means, 12 ... Communication timing calculation means, 13 ... Impulse signal transmission means, 14 ... Tuning determination means, 15 ... Data signal communication means, 16 ... Time slot width measurement means, 17 ... Angular velocity Changing means, 18 ... node position detecting means, 19 ... impulse reception width storing means, 20 ... on / off control means, RA1, RA11, RA12, RA2, RA3, RA4 ... impulse signal receiving operation period, A to J, N1 to N16,. Node, DD, DE ... Data signal.

Claims (4)

A transmission medium access control apparatus that performs access control on a transmission medium by allowing the own node to access the transmission medium using any of a plurality of time slots that circulate periodically,
With the receiving operation of receiving the state variable signal indicating the operation timing of another node, a state variable signal communication unit for performing a transmission operation of transmitting a state variable signal indicating the operation timing of the own node intermittently,
Based on the state variable signals from other nodes to which the state variable signal communication unit has received, shifts the operating timing of the own node, the state variable to generate a state variable signal from the local node that reflects this transition A timing determination unit that recognizes a time slot in which one or a plurality of other nodes in the vicinity of which the local node and the state variable signal reach can transmit a data signal, while giving to the signal communication unit;
A data transmission unit that periodically transmits a data signal for each time slot determined by the operation timing of the own node;
A data receiving unit for receiving data signals from other nodes;
A monitoring period setting unit configured to set a predetermined monitoring period at a predetermined phase position determined on the basis of a time slot of the own node on the period when the operation state is in a predetermined steady state;
When in the steady state, during the period other than the monitoring period on the cycle, the reception operation by the state variable signal communication unit is stopped, and the reception state of the state variable signal from other nodes during the monitoring period fluctuated. In this case, it is determined that a steady state has collapsed between the one or more other nodes in the vicinity, and the state variable signal communication unit performs a reception operation even during a period other than the monitoring period on the cycle. A transmission medium access control device comprising a signal reception operation control unit. The transmission medium access control device according to claim 1,
When changing the time width of the time slot of each node according to the number of nodes located in the vicinity, the own node that has not transmitted and received the state variable signal and the data signal with other nodes until then, A transmission medium access comprising: a state variable signal transmission control unit that causes the state variable signal communication unit to transmit the state variable signal at a time interval shorter than a predetermined value when newly appearing in the vicinity. Control device. A transmission medium access control method for performing access control on a transmission medium by allowing the own node to access the transmission medium using any of a plurality of periodically circulated time slots,
State variable signal communication unit, the receive operation of receiving the state variable signal indicating the operation timing of another node, performs the transmission operation of transmitting a state variable signal indicating the operation timing of the own node intermittently,
The timing determination unit, based on the state variable signals from other nodes to which the state variable signal communication unit has received, shifts the operating timing of the own node, generates a state variable signal from the local node that reflects this transition And providing the state variable signal communication unit, and recognizing a time slot in which the local node and one or more other nodes in the vicinity where the state variable signal reaches can transmit a data signal,
The data transmission unit periodically transmits a data signal for each time slot determined by the operation timing of the node,
The data receiver receives data signals from other nodes,
When the operation state is in a predetermined steady state, the monitoring period setting unit sets a predetermined monitoring period at a predetermined phase position determined with reference to the time slot of the own node on the cycle,
When the state variable signal reception operation control unit is in the steady state, the state variable signal reception operation control unit stops the reception operation by the state variable signal communication unit in a period other than the monitoring period on the cycle, and the other during the monitoring period. When the reception status of the state variable signal from the node fluctuates, it is determined that the steady state has collapsed among the one or more other nodes in the vicinity, and the state is detected even in a period other than the monitoring period on the cycle. A transmission medium access control method characterized by causing a variable signal communication unit to perform a receiving operation. A transmission medium access control program for performing access control on a transmission medium by causing the own node to access the transmission medium using any of a plurality of time slots that circulate periodically.
With the receiving operation of receiving the state variable signal indicating the operation timing of another node, a state variable signal communication function of executing a transmission operation of transmitting a state variable signal indicating the operation timing of the own node intermittently,
Based on the state variable signals from other nodes to which the state variable signal communication function, received, shifts the operating timing of the own node, the state variable to generate a state variable signal from the local node that reflects this transition A timing determination function for giving a signal communication function and recognizing a time slot in which the local node and one or a plurality of other nearby nodes to which the state variable signal reaches can transmit a data signal;
A data transmission function for periodically transmitting a data signal for each time slot determined by the operation timing of the own node;
A data receiving function for receiving data signals from other nodes;
A monitoring period setting function for setting a predetermined monitoring period at a predetermined phase position determined with reference to the time slot of the own node on the period when the operation state is in a predetermined steady state;
When in the steady state, in the period other than the monitoring period on the cycle, the reception operation by the state variable signal communication function is stopped, and the reception state of the state variable signal from other nodes during the monitoring period fluctuated. In this case, it is determined that a steady state has collapsed between the one or more other nodes in the vicinity, and the state variable signal communication function performs a reception operation even during a period other than the monitoring period on the period. A transmission medium access control program for realizing a signal reception operation control function.

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