JP5505266B2 - Wireless communication apparatus and program, and communication system - Google Patents

Description

  The present invention relates to a wireless communication device, a program, and a communication system, and can be applied to, for example, a wireless multi-hop network including a plurality of wireless communication devices that are required to save power.

  In order to realize power saving of communication nodes (wireless communication devices) constituting the wireless communication multi-hop network, an intermittent operation method is effective. As a transmission / reception timing control technique necessary for realizing the intermittent operation of the communication node, there is a conventional technique called LPL (Low Power Listening).

  In a communication node adopting the LPL method, a receiving communication node periodically repeats a dormant state (sleep state) and a reception standby state (reception standby state), and the transmission side communication node enters an unknown reception standby state. In order to match the timing, an activation signal (hereinafter referred to as “Wakeup signal”) is sent. The receiving communication node that receives the Wakeup signal prepares for data reception.

  Non-Patent Document 1 introduces and compares the X-MAC method and the TURTLE method based on the LPL method.

  FIG. 7 is a timing chart showing an operation when a frame is transmitted from a communication node on the transmission side to a communication node on the reception side in the conventional communication system. Hereinafter, the operation of the conventional communication system will be described with reference to FIG. In FIG. 7, the communication node on the receiving side is assumed to be a communication node that employs the above-described LPL method.

  First, it is assumed that a data frame to be transmitted has occurred in the communication node on the transmission side. Then, from the time point T101, the communication node on the transmission side waits to receive a Wakeup Ack signal frame that is a response to the Wakeup signal from the communication node on the reception side and the transmission of the Wakeup signal to the reception side communication node. The process (reception standby process) is repeated. Here, it is assumed that the transmission side communication node repeats the above-described Wakeup signal frame transmission and reception standby processing until a Wakeup Ack signal frame can be received from the reception side communication node.

  On the other hand, in the communication node on the reception side, the reception waiting state of the Wakeup signal from the communication node on the transmission side is intermittently performed every predetermined operation cycle. Here, the communication node on the receiving side is in a reception standby state for a predetermined transition time (hereinafter referred to as “t (seconds)”) during a predetermined operation cycle (hereinafter referred to as “Tr (seconds)”). It shall be That is, in the communication node on the receiving side, the reception standby state for t seconds and the sleep state for Tr-t seconds are alternately repeated.

  In FIG. 7, the communication node on the receiving side is in a reception standby state from timing T201 to timing T202, and is in a reception standby state thereafter until timing T203.

  Then, the communication node on the receiving side enters the reception standby state again from timing T203. Thereafter, the communication node on the reception side is in a reception standby state until time T204, and it is assumed that a Wakeup signal frame is received from the communication node on the transmission side. When receiving the Wakeup signal frame, the receiving communication node starts transmission of the Wakeup Ack signal to the transmitting communication node from timing T204 thereafter. Then, it is assumed that the communication node on the receiving side has completed the frame transmission of the Wakeup Ack signal at the timing T205. When the communication node on the reception side completes the frame transmission of the Wakeup Ack signal, the reception side communication node enters a reception standby state in order to receive the data frame from the communication node on the transmission side.

  When the communication node on the transmission side receives the Wakeup Ack signal frame transmitted from the communication node on the reception side described above, transmission of the data frame to the communication node on the reception side is started from the subsequent timing T102. Then, it is assumed that the transmission side communication node has completed the transmission of the data frame at the timing T103. Then, the communication node on the transmission side enters a reception standby state in order to receive a reception confirmation signal (Ack signal) from the communication node on the reception side.

  When the receiving communication node confirms that the data frame transmitted from the transmitting communication node has been normally received, the Ack signal frame is transmitted from the subsequent timing T206.

  Then, the transmission side communication node receives the Ack signal from the reception side communication node, and the transmission / reception process of the data frame between the two communication nodes is completed.

Yuki Kubo, Kentaro Yanagihara, Masanori Nozaki, Shigeru Fukunaga, Toshihisa Nakai, “Low-latency, low-power, energy-saving wireless multi-hop communication suitable for data-collecting sensor networks”, IEICE Transactions (B), Vol. J92-B, no. 8, pp. 1225-1235, August 2009 Edited by The Japan Radio Industry Association, “Standard equipment for specified low-power radio stations for 950 MHz band telemeters, radio equipment for telecontrol and data transmission (ARIB STD-T96)”, [Online], INTERNET, [November 8, 2010 Search], <URL: http://www.arib.or.jp/tyosakenkyu/kikaku_tushin/tsushin_std-t096.html>

  The operation of the communication system employing the conventional LPL method for each communication node is as described above. Furthermore, in a communication medium such as a radio, communication in the same frequency band is performed between communication systems or between communication nodes in the system. In order to interfere with each other, a communication rule for eliminating it may be defined.

  For example, for a communication system in the 950 MHz band, as shown in Non-Patent Document 2, the definition of the communication system is standardized. In Non-Patent Document 2, a communication rule as shown in FIG. 8 is defined for a 950 MHz band communication system.

  FIG. 9 is a timing chart showing a data transmission operation of a conventional communication node adopting the communication rule as shown in FIG.

  In a communication node adopting the communication rule shown in FIG. 8, when data is transmitted to another communication node, a carrier sense operation is performed during a predetermined carrier sense time (hereinafter referred to as “a (second)”), and the carrier After the sense is normally completed, data transmission can be performed only during a transmission possible time (hereinafter referred to as “b (second)”) according to a predetermined transmission time control. In the communication node adopting the communication rule shown in FIG. 8, after data transmission, data transmission must be stopped for a transmission pause time (hereinafter referred to as “c (second)”) related to the transmission time control. Don't be.

  In the data transmission / reception between the communication nodes adopting the above-described LPL method and the communication rule as shown in FIG. 8 described above, when the communication node on the transmission side transmits the Wakeup signal, the communication node on the transmission side It is necessary to match the timing of the data transmission available time with the timing of the reception standby period of the receiving communication node. However, in the conventional communication system, there is a case where data frame transmission / reception cannot be started at an early stage when the above timing is not met.

  Therefore, even if there is a restriction on the data transmission possible time of the transmission side communication node and the data reception possible time of the reception side communication node, a wireless communication apparatus and program capable of starting data transmission / reception early, and a communication system Is desired.

  In the first aspect of the present invention, when performing data transmission by wireless communication to a receiving-side wireless communication device that is in a data reception standby period in which data can be received by wireless communication in each intermittent operation cycle in a dormant state, In a wireless communication apparatus that sets a data transmission stop period for stopping data transmission for a period equal to or longer than the minimum data transmission stop period for each data transmission period with the maximum data transmission period as an upper limit, (1) the wireless communication apparatus on the receiving side (2) a data transmission stop period or data transmission of the wireless communication device using information held in the intermittent operation cycle information holding unit; Data transmission period determining means for determining the length of the period; and (3) controlling the operating state of the wireless communication apparatus according to the determination of the data transmission period determining means. And having a work state control means.

  The wireless communication program of the second aspect of the present invention performs data transmission by wireless communication to a reception-side wireless communication device that is in a data reception standby period in which data can be received by wireless communication at each intermittent operation cycle in a pause state. At this time, for each data transmission period whose upper limit is the longest data transmission period, a computer mounted on the wireless communication apparatus that sets a data transmission stop period for stopping data transmission for a period equal to or longer than the minimum data transmission stop period is (1) Intermittent operation cycle information holding means for holding information on the intermittent operation cycle in the wireless communication apparatus on the receiving side, and (2) using the information held in the intermittent operation cycle information holding means, A data transmission period determining means for determining a data transmission stop period or a length of the data transmission period; and (3) according to the determination of the data transmission period determining means, Characterized in that to function as an operating state controlling means for controlling an operation state of the line communication device.

  A communication system according to a third aspect of the present invention includes one or more wireless communication apparatuses according to the first aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, even if there exists a restriction | limiting in the data transmission possible time of a transmission side communication node, and the data reception possible time of a reception side communication node, data transmission / reception can be started at an early stage.

It is the block diagram shown about the functional structure of the communication node which concerns on 1st Embodiment. 1 is a block diagram showing an overall configuration of a communication system according to a first embodiment. It is the flowchart shown about the operation | movement in which the communication node of the transmission side which concerns on 1st Embodiment transmits a data frame. It is the flowchart shown about the operation | movement in which the communication node of the receiving side concerning 1st Embodiment receives a data frame. 6 is a timing chart showing an operation in a conventional communication system when a transmission suspension time of a transmission side communication node and a reception standby state time of a reception side communication node are synchronized. It is the block diagram shown about the functional structure of the communication node which concerns on 2nd Embodiment. It is the timing chart which showed the data transmission / reception operation between the communication nodes which employ | adopted the conventional LPL system. It is explanatory drawing shown about the communication rule in the conventional communication system. It is the timing chart shown about the data transmission operation | movement of the communication node which employ | adopted the conventional communication rule.

(A) First Embodiment Hereinafter, a wireless communication apparatus and program according to the present invention, and a first embodiment of a communication system will be described in detail with reference to the drawings. Note that the wireless communication apparatus of the first embodiment is a communication node.

(A-1) Configuration of the First Embodiment FIG. 2 is a block diagram showing the overall configuration of the communication system 1 of the first embodiment. In FIG. 2, the reference numerals in parentheses are used only in the second embodiment to be described later.

  In FIG. 2, for simplicity of explanation, it is illustrated that only two communication nodes 10 (10-1, 10-2) are arranged in the communication system 1, but the communication node 10 is arranged. The number to be played is not limited. For example, in the communication system 1, a large number of communication nodes 10 may be arranged to form a wireless multi-hop network. The communication system 1 may be applied to, for example, a sensor network having a large number of sensor nodes that require power saving.

  Here, for the sake of simplicity, it is assumed that the communication node 10-1 operates as a data frame transmission side node and the communication node 10-2 operates as a data frame reception side node. The communication nodes 10-1 and 10-2 are described as having the same configuration here, but may have different configurations. For example, the communication node 10-1 includes only a configuration for transmitting a data frame to the communication node 10-2 (assuming a configuration for receiving a control signal such as a Wakeup Ack signal), and a data frame transmission device You may make it comprise as. Further, the communication node 10-2 has a configuration only for receiving a data frame from the communication node 10-1 (assuming a configuration for transmitting a control signal such as a Wakeup Ack signal) and receives a data frame. You may make it comprise as an apparatus.

  Here, it is assumed that the same communication rule as that of the communication node on the transmission side in FIG. 9 is applied to each communication node 10 of the communication system 1. That is, when transmitting data to the communication node 10-2, the communication node 10-1 performs a carrier sense operation for the carrier sense time a (seconds), and after the carrier sense is normally completed, the transmittable time b ( It is assumed that data transmission can be performed only for a period of (second) or less, and after the data transmission, the data transmission must be suspended for a transmission suspension time c (seconds) or longer.

  In addition, at least the communication node 10-2 is configured to perform an operation based on the above-described LPL method, and when in a dormant state, during the operation cycle Tr (seconds), a reception standby state is performed for a transition time t (seconds). It shall be

  Next, an outline of the internal configuration of the communication node 10 will be described.

  FIG. 1 is a block diagram showing a functional configuration of the communication node 10 (10-1, 10-2).

  The communication node 10 includes a communication unit 101, a communication control unit 102, a communication data processing unit 103, an intermittent operation control unit 104, a timer 105, a power supply unit 106, a Wakeup signal processing unit 107, a Wakeup signal generation unit 108, and a transmission time limit control unit. 109, a transmission time / transmission pause time adjustment unit 110, an adjacent node operation cycle storage unit 111, and a timer 112.

  The communication node 10 is a device having an execution configuration of programs such as a CPU, ROM, RAM, EEPROM, hard disk, and an interface for wireless communication (not limited to one, so that a plurality of devices can be distributedly processed. 1) may be constructed by installing the wireless communication program or the like according to the embodiment, and even in that case, it can be functionally shown as in FIG. Note that hardware used for the communication node 10 can be the same as that of a communication node that performs existing wireless communication.

  The communication unit 101 serves as an interface for the communication node 10 to wirelessly communicate with other communication nodes 10. When the destination of the received frame is its own node (for example, when the destination is an Ethernet (registered trademark) frame, the communication unit 101 determines the frame by using an identification ID such as a MAC address). To hand over.

  The power supply unit 106 supplies power to each component of its own node according to the control of the intermittent operation control unit 104.

  The intermittent operation control unit 104 uses the timer 105 to determine the transition timing of the state of the own node. In addition, the intermittent operation control unit 104 controls the state of its own node by controlling the power supply unit 106. The details of the operation of the intermittent operation control unit 104 will be described in detail in the description of operations described later.

  The intermittent operation control unit 104 manages and controls the state of the communication node 10 to one of three states of an operation state, a sleep state (sleep state), and a transmission / reception state. Here, the “operation state” refers to a state in which the communication node 10 can receive a frame from another communication node 10. The dormant state (sleep state) refers to a state in which the communication node 10 cannot transmit / receive a frame to / from another communication node 10. Furthermore, it is assumed that the “transmission / reception state” is a state in which the communication node 10 can both transmit and receive frames with other communication nodes 10.

  The timer 105 is a timer that measures the time used for the operation of the intermittent operation control unit 104.

  The communication control unit 102 controls data transmission / reception by the communication unit 101. For example, the communication control unit 102 causes the communication unit 101 to receive a frame from another communication node 10 (a reception standby state) or to transmit data to another communication node 10. Take control. The communication control unit 102 stops operating when its own node is in a dormant state, but can operate by receiving power supply from the power source unit 106 when it enters an operating state or a transmission / reception state. The communication control unit 102 can perform both frame reception waiting and frame transmission control for the communication unit 101 while the node is in a transmission / reception state. On the other hand, when the own node is in an operating state, the communication control unit 102 can only control frame reception standby with respect to the communication unit 101 and cannot control frame transmission.

  The communication data processing unit 103 performs data processing related to a frame transmitted and received by the communication control unit 102.

  The communication data processing unit 103 performs reception confirmation processing (error check etc.) of the data frame received from the other communication node 10 received by the communication control unit 102, and when normal reception is confirmed, an ACK signal ( (Acknowledgment response signal) is generated and sent back to the communication node 10 as the transmission source via the communication unit 101.

  Further, when a data frame to be transmitted to another communication node 10 occurs in the own node, the communication data processing unit 103 gives the data frame to the communication control unit 102 for transmission. The case where a data frame is transmitted to another communication node 10 in the communication node 10 means that, for example, the communication data processing unit 103 processes the upper layer routing control protocol for the data frame received from the other communication node 10. As a result, the data is transferred to the next communication node on the route toward the final destination communication node 10, or the upper layer component (such as an application (not shown)) of the own node generates a data frame. Etc.

  When the Wakeup signal processing unit 107 is notified by the communication control unit 102 that the Wakeup signal has been received, the Wakeup signal processing unit 107 performs control processing of the intermittent operation control unit 104, generates a Wakeup Ack signal that responds to the transmission source of the Wakeup signal, etc. Is to do.

  The wakeup signal generation unit 108 generates a wakeup signal frame to be transmitted when the own node transmits a data frame to another communication node 10.

  The adjacent node operation cycle storage unit 111 stores information on the operation cycle of the communication node 10 in the vicinity of the own node (for example, an area where direct wireless communication is possible). The operation cycle information set in the adjacent node operation cycle storage unit 111 may be set to a uniform specified value in the communication system 1 or may estimate the operation cycle for each communication node 10. Good. Here, description will be made assuming that information on the operation cycle Tr is stored in the operation cycle storage unit 111 of the adjacent node of each communication node 10 as a standard value unified in the communication system 1.

  The transmission time / transmission suspension time adjustment unit 110 applies the transmission time / transmission suspension time adjustment unit in its own node based on the operation cycle Tr stored in the adjacent node operation cycle storage unit 111 and the transmission suspension time c defined in the communication system 1 as a standard. A transmission suspension time c ′ (second) (a time longer than the transmission suspension time c) is calculated and determined. The transmission suspension time c ′ determined by the transmission time / transmission suspension time adjustment unit 110 will be described in detail in the description of the operation described later.

  Note that the timing at which the transmission time / transmission pause time adjustment unit 110 calculates the transmission pause time c ′ is not limited, and for example, a pre-calculated value may be applied, or may be calculated whenever necessary. You may do it.

  The transmission time limit control unit 109 performs control related to frame transmission in the own node. When the communication control unit 102 transmits a frame such as a wakeup signal or data in the communication control unit 102, the transmission time limit control unit 109 is defined in the timer 112 as a standard when the node is in a standby state (not the transmission pause time). The carrier sense time a is set, and the communication control unit 102 and the communication unit 101 are caused to perform the carrier sense operation. Then, after the elapse of the carrier sense time a, the transmission time limit control unit 109 shifts the communication unit 101 and the communication control unit 102 from the carrier sense operation state to the transmission state.

  Then, the transmission time limit control unit 109 sets the transmission possible time b defined as a standard in the timer 112 after the completion of the carrier sense, and instructs the communication control unit 102 to prohibit transmission after the transmission possible time b has elapsed. put out. Then, the transmission time limit control unit 109 activates the timer 112, sets the transmission suspension time c ′ determined by the transmission time / transmission suspension time adjustment unit 110, and sets the transmission suspension time c ′ to the communication control unit 102 after the transmission suspension time c ′ elapses. Sends a send standby instruction.

(A-2) Operation of the First Embodiment Next, the operation of the communication system 1 of the first embodiment having the above configuration will be described.

  Here, first, the data frame transmission process to the communication node 10-2 in the communication node 10-1 on the transmission side will be described, and then the data frame reception process in the communication node 10-2 will be described.

(A-2-1) Data Transmission Operation FIG. 3 is a flowchart showing data frame transmission processing to the communication node 10-2 in the communication node 10-1 on the transmission side.

  First, in the communication node 10-1, a data frame to be transmitted to the communication node 10-2 is generated, and the data frame is delivered from the communication data processing unit 103 to the communication control unit 102. Then, the communication control unit 102 instructs the Wakeup signal generation unit 108 to generate a Wakeup signal for the communication node 10-2 (S101).

  Then, the transmission time limit control unit 109 sets the carrier sense time a in the timer 112, and causes the communication unit 101 and the communication control unit 102 to perform the carrier sense operation during the carrier sense time a (S102). Here, the following description will be given on the assumption that the carrier sense operation is successful.

  Then, the transmission time limit control unit 109 sets the transmittable time b in the timer 112 and starts it. Then, the wakeup signal generation unit 108 instructs the intermittent operation control unit 104 to set the state of the own node to the transmission / reception state. Then, the intermittent operation control unit 104 controls the state of the communication node 10-1 to the transmission / reception state (S103).

  Then, the Wakeup signal generation unit 108 sends out the Wakeup signal to the communication node 10-2 via the communication control unit 102 and the communication unit 101, sets the communication unit 101 in a standby state for a predetermined time, and receives the Wakeup Ack signal. Wait for it to arrive. Then, the wakeup signal generation unit 108 waits until the wakeup Ack signal reaches the communication unit 101 until the transmittable time b elapses (until the timer 112 times out) after the above-described carrier sense operation ends. During this time, the same processing is repeated (S104).

  Then, the wakeup signal generation unit 108 confirms whether or not the reception of the wakeup Ack signal is successful in step S104 described above (S105). If the wakeup signal generation unit 108 confirms that the wakeup signal is successful, the operation starts from step S106 described later. However, if it is confirmed that the operation has failed, the operation starts from the processing in step S109 described later.

  If it is determined in step S105 that reception of the Wakeup Ack signal has failed, the transmission suspension time c ′ determined by the transmission time / transmission suspension time adjustment unit 110 is notified to the transmission time limit control unit 109. The Then, the transmission time limit control unit 109 sets the transmission suspension time c ′ in the timer 112 and controls the communication control unit 102 to transmit a frame until the transmission suspension time c ′ elapses (until the timer 112 times out). Is prohibited (S109). Then, after the elapse of the transmission suspension time c ′, the communication node 10-1 enters a standby state (a state in which frame transmission can be performed), returns to the process of step S 102 described above, and resumes the process from the carrier sense operation.

  If it is determined in step S105 described above that the reception of the Wakeup Ack signal is successful, the Wakeup signal generation unit 108 stops transmitting the Wakeup signal, and indicates that the Wakeup Ack signal has been received (data frame transmission has been completed). To the communication control unit 102. Then, the communication control unit 102 transmits the data frame given from the communication data processing unit 103 to the communication node 10-2 via the communication unit 101. Then, the communication control unit 102 controls the communication unit 101 to be in a standby state, and receives an Ack signal (acknowledgment signal for data frame transmission) from the communication node 10-2 within a predetermined time limit. Wait (S106).

  Then, the communication control unit 102 confirms whether or not the reception of the Ack signal from the communication node 10-2 is successful (S107). If the reception is successful, the communication control unit 102 operates from the process of step S110 described later, and receives. In the case of failure, the operation starts from the processing in step S108 described later.

  If it is confirmed in step S107 that reception of the Ack signal has failed, the communication control unit 102 performs predetermined processing (for example, retransmission processing if retransmission is set, and communication data processing if not performed). (Processing such as returning a failure to transmit data) to the unit 103 (S108).

  When the timer 112 times out during the processing of the above steps S106 to S108 (when the transmission pause time c ′ has elapsed), the same processing as in the above step S109 is performed, After the communication node 10-1 returns to the standby state, it is necessary to execute the carrier sense operation and restart the process.

  When the process of step S108 is completed, or when it is confirmed that the Ack signal has been successfully received in step S107, the transmission suspension time c ′ determined by the transmission time / transmission suspension time adjustment unit 110 is determined. Is notified to the transmission time limit control unit 109. Then, the transmission time limit control unit 109 sets the transmission suspension time c ′ in the timer 112 and controls the communication control unit 102 to transmit a frame until the transmission suspension time c ′ elapses (until the timer 112 times out). Is prohibited (S110).

  Note that at the start of step S110, the communication node 10-1 is not immediately set to the transmission pause time, but waits until the timer 112 next times out (until the transmittable time b elapses), You may make it perform the process of step S110.

(A-2-2) Data Receiving Operation FIG. 4 is a flowchart showing a data frame receiving process from the communication node 10-1 in the receiving communication node 10-2.

  Here, the initial state of the communication node 10-2 will be described as being in a dormant state.

  First, it is assumed that a trigger for notifying the lapse (timeout) of the operation cycle Tr is given from the timer 105 to the intermittent operation control unit 104 (S201).

  When receiving the trigger notification from the timer 105, the intermittent operation control unit 104 instructs the power supply unit 106 to supply power to each unit, and shifts the state of the communication node 10-2 to the operation state. Further, a transition time t to the next hibernation state is set in the timer 105 (S202).

  Upon receiving power supply from the power supply unit 106, the communication control unit 102 controls the communication unit 101 until the transition time t elapses or until a frame addressed to the own node (communication node 10-2) is received. In the meantime, a reception standby state is set (S203). Note that when the communication unit 101 receives a frame addressed to the own node during the reception standby state, the communication unit 101 delivers the frame to the communication control unit 102.

  Next, the communication control unit 102 confirms the processing status of step S203 described above (S204). Here, when it is confirmed that the frame of the Wakeup signal addressed to the own node is given before the transition time t elapses, the communication control unit 102 operates from the process of step S206 described later. On the other hand, when it is confirmed that the frame of the Wakeup signal addressed to the own node has not been given before the transition time t elapses, the communication control unit 102 operates from the process of step S205 described later.

  In step S203, there is a possibility that a frame other than the Wakeup signal addressed to the own node may be given, but here it is assumed that the frame reaching the communication node 10-2 in the dormant state is only the frame of the Wakeup signal. To do. When a frame other than the Wakeup signal is given to the communication node 10-2 in the dormant state, the communication control unit 102 receives predetermined processing (for example, processing for ignoring the frame or reception of the frame and passes it to the upper layer) Processing, etc.) may be performed.

  In step S204 described above, when it is confirmed that the frame of the Wakeup signal addressed to the own node has not been given until the transition time t elapses, the communication control unit 102 pauses the own node in the intermittent operation control unit 104. Instruct to get into the state. Then, the intermittent operation control unit 104 sets Tr-t in the timer 105 if the own node is in the operating state, and instructs the power supply unit 106 to stop sharing the power supply to each unit. The process is completed (S205). Then, the communication node 10-2 operates by returning to the process of step S201 described above.

  On the other hand, in the above-described step S204, when it is confirmed that the Wakeup signal frame addressed to the own node is given before the transition time t has elapsed, the communication control unit 102 first determines the received Wakeup signal frame. The signal is delivered to the wakeup signal processing unit 107 (S206).

  Next, the wakeup signal processing unit 107 instructs the intermittent operation control unit 104 to change the node state from the operation state to the transmission / reception state, and the intermittent operation control unit 104 controls the own node to the transmission / reception state (S207).

  Next, the Wakeup signal processing unit 107 generates a Wakeup Ack signal frame (that is, a frame addressed to the communication node 10-1) using the transmission source ID included in the received Wakeup signal frame as a destination ID, and performs communication control. Delivered to the unit 102 (S208).

  Next, the communication control unit 102 controls the communication unit 101 to the transmission state, and sends a Wakeup Ack signal frame from the communication unit 101 (S209).

  When the communication node 10-2 transmits the frame of the Wakeup Ack signal, it is necessary to perform the carrier sense operation during the carrier sense time a as in the case of FIG. Further, the communication control unit 102 is controlled by the transmission time limit control unit 111 during frame transmission, as in the case of FIG. 3 described above. Here, at the operation start time of step S209, the communication node 10-2 is in a standby state (not in a transmission suspension state), immediately starts a carrier sense operation, and a frame of a Wakeup Ack signal has been created. Will be explained.

  Next, the communication control unit 102 returns the communication unit 101 to a reception standby state (S210).

As described above, when the communication node 10-1 on the transmission side receives the Wakeup Ack signal, the communication node 101 receives the data frame and delivers it to the communication control unit 102 in order to perform processing to send out the data frame. S211)
Next, the communication control unit 102 gives the received data frame to the communication data processing unit 203, sends out the Ack signal frame to the transmission source node (communication node 10-1) via the communication unit 101, and receives the data. The operation is completed (S212).

  If the transmittable time b has not elapsed after the completion of the carrier sensing operation performed in step S209 described above at the start of the operation in step S212, an Ack signal frame can be immediately transmitted. On the other hand, if the communication node 10-2 is in the transmission suspension time at the start of the operation in step S212, the Ack signal frame transmission is performed unless the carrier sense operation is performed again after the transmission suspension time. Can't do it.

  Next, the communication data processing unit 203 instructs the intermittent operation control unit 104 to set the node state to the dormant state, and the intermittent operation control unit 104 sets the operation cycle Tr in the timer 105 and sends it to the power supply unit 106. The power supply is instructed to be stopped, and the local node is put into a dormant state (S213).

(A-2-3) Transmission Pause Time Determination Method Next, the transmission pause period determined by the transmission time / transmission pause time adjustment unit 110 in steps S110 and S119 described above will be described.

  The transmission time / transmission suspension time adjustment unit 110 uses the transmission suspension time c ′ for the communication node 10-2 that is the transmission destination of the data frame, using information on the operation cycle Tr stored in the adjacent node operation cycle storage unit 111. And decide. The transmission suspension time c ′ determined by the transmission time / transmission suspension time adjustment unit 110 needs to be equal to or longer than the transmission suspension time c defined by the standard.

  In this example, the transmission time / transmission pause time adjustment unit 110 determines that the phase of the intermittent operation (operation in the reception standby state) on the operation cycle Tr of the communication node 10-2 on the reception side is the previous time of the own node. It is assumed that a new transmission pause time c ′ is determined so as not to overlap with the transmittable time.

  In other words, the transmission time / transmission pause time adjustment unit 110 is configured such that the phase (timing) at which the communication node 10-2 on the reception side is in a reception standby state and the own node (communication node 10-1) on the transmission side are suspended. A new transmission pause time c ′ is determined so that the phase (timing) to be in a state does not overlap (so as to make a transition in the direction of shifting). For example, the transmission time / transmission suspension time adjustment unit 110 adjusts the transmission suspension time c ′ to set the reception standby state in the communication node 10-2 on the reception side and the own node (communication node 10 on the transmission side). In the case where -1) approximates the period in which the transmission is suspended, the above-described phase shift may be generated by making these periods different.

  There are various methods for determining the transmission suspension time c '. For example, the transmission suspension time c' may be determined by a calculation method described below.

  The transmission time / transmission pause time adjustment unit 110 obtains a transmission pause time c ′ that satisfies the following expression (1) so that the above-described phase shifts.

n (a + b + c ′) = Tr + b (1)
The transmission time / transmission pause time adjustment unit 110 may obtain the transmission pause time c ′ by the following equation (2) when Tr> a + b + c. However, in the formula (2), n is a natural number and satisfies the relationship shown in the following formula (3). In the following formula (3), floor (x) is a truncation function.

c ′ = (Tr + b) / n−b−a (2)
n <= floor ((Tr + b) / (a + b + c)) (3)
The transmission time / transmission pause time adjustment unit 110 obtains the transmission pause time c ′ by the following equation (4) when b <= Tr, c + a <= Tr, and Tr <= a + b + c. Anyway.

c ′ = Tr−a (4)
Further, the transmission time / transmission suspension time adjustment unit 110 may obtain the transmission suspension time c ′ by the following equation (5) when b <Tr <c + a. However, in the following formula (5), n is a natural number and satisfies the following formula (6). In the following formula (6), ceil (x) is a round-up function.

c ′ = Tr * n−a (5)
n> = ceil ((c + a) / Tr) (6)
Furthermore, the transmission time / transmission suspension time adjustment unit 110 may obtain the transmission suspension time c ′ by the following equation (7) when Tr <= b.

c ′ = c (7)
(A-3) Effects of First Embodiment According to the first embodiment, the following effects can be achieved.

  According to the first embodiment, in the communication node 10-1 to which the communication rules as shown in FIG. 8 described above must be applied, the transmission suspension time of the own node and the suspension of the communication node 10-2 on the receiving side. Time becomes difficult to synchronize. Thereby, in the communication node 10-1, generation | occurrence | production of the state that time until it becomes possible to transmit a data frame becomes very long can be suppressed.

  In particular, in a communication system in which Tr≈a + b + c, the transmission side communication node, the transmission pause time, and the reception pause time are easy to synchronize, so that the communication node 10 of the first embodiment is introduced. Is preferred.

  FIG. 5 is a timing chart showing an operation in the conventional communication system when the transmission suspension time of the communication node on the transmission side is synchronized with the period of the reception standby state of the communication node on the reception side.

  As shown in FIG. 5, in the case of Tr≈a + b + c, the transmission suspension period of the communication node on the transmission side and the reception standby state period of the communication node on the reception side are easily synchronized. In this case, it may take a very long time until the timing when the receiving communication node operates in the transmittable section in which the transmitting communication node can transmit the Wakeup signal, or there may be a problem that the transmitting communication node will not be able to transmit forever. . However, in the communication system 1 of the first embodiment, as described above, the transmission suspension time of the communication node 10-1 on the transmission side and the suspension time of the communication node 10-2 on the reception side are difficult to synchronize. The situation as shown in FIG.

(B) Second Embodiment Hereinafter, a second embodiment of a wireless communication apparatus and program and a communication system according to the present invention will be described in detail with reference to the drawings. Note that the wireless communication apparatus according to the second embodiment is a communication node.

(B-1) Configuration and Operation of Second Embodiment A communication system 1A of the second embodiment can also be shown using FIG. In FIG. 2, the reference numerals in parentheses are those used only in the second embodiment.

  Hereinafter, the difference between the second embodiment and the first embodiment will be described.

  In the communication system 1A of the second embodiment, the communication node 10 (10-1, 10-2) is replaced with the communication node 10A (10A-1, 10A-2). Is different.

  FIG. 6 is a block diagram illustrating a functional configuration of the communication node 10A according to the second embodiment.

  The communication node 10A is different from the communication node 10 of the first embodiment in that an adjacent node operation cycle notification unit 113 is added.

  The adjacent node operation cycle notification unit 113 generates a signal (hereinafter referred to as “operation cycle notification signal”) for notifying the communication node 10 </ b> A of the information of the operation cycle Tr of the own node, and supplies the signal to the communication control unit 102. . Then, the communication control unit 102 notifies the operation cycle while receiving the control of the carrier sense, the transmittable time, and the transmission pause time by the transmission control of the transmission time limit control unit 109, similarly to the data frame, the frame of the Wakeup signal, and the like. A signal frame (including information on the intermittent operation cycle Tr and information on the identification ID of the own node) is notified to the communication nodes 10A around the own node.

  The operation cycle notification signal may be transmitted alone (transmitted as a frame having only the signal), but participates when each communication node 10A participates in the wireless communication network in the communication system 1A. For example, it may be included in a control signal (for example, a command frame for Join processing) and transmitted. Further, an operation cycle notification signal may be included in a frame for exchanging control signals such as routing information with surrounding communication nodes.

  In the communication node 10A, when the frame of the operation cycle notification signal is given from the other communication node 10A, it is stored in the adjacent node operation cycle storage unit 111 together with the identification ID of the communication node 10A as the transmission source.

  In the communication node 10A, when transmitting a data frame, the transmission time / transmission suspension time adjustment unit 110 refers to the adjacent node operation cycle storage unit 111 and transmits the transmission suspension time c ′ as in the first embodiment. To decide. In the communication node 10A, the transmission time limit control unit 109 controls the transmittable time and the transmission suspension time.

  In the communication node 10A, if the operation cycle Tr related to the communication node 10A identification ID (address) of the transmission destination to which the data frame is to be transmitted is not stored in the adjacent node operation cycle storage unit 111, the communication node 10A is based on the operation cycle Tr. The transmission pause time cannot be controlled. Therefore, in this case, the transmission time / transmission pause time adjustment unit 110 may randomly determine c ′ based on the parameters b and c. For example, using the random number r (0 <r <1) (for example, a random number generated by random number generating means (not shown) may be applied), the transmission pause time c ′ is obtained by the following equation (8). You may do it.

c ′ = c + r * (a + b + c) (8)
(B-2) Effects of Second Embodiment According to the second embodiment, the following effects can be achieved.

  In the communication system 1A, even if a network is formed by the communication nodes 10A having different operation cycles, the same effect as that of the first embodiment can be obtained by sharing the operation cycle between the communication nodes 10A.

  Further, in the communication system 1A, even when the transmission-side communication node 10A-1 at the initial time does not obtain the operation cycle information of the reception-side communication node 10A-2, the transmission pause time is determined using random numbers. Thus, it is possible to suppress synchronization between the transmission suspension time of the own node and the suspension time of the communication node 10A-2 on the receiving side.

(C) Other Embodiments The present invention is not limited to the above-described embodiments, and may include modified embodiments as exemplified below.

(C-1) In each of the embodiments described above, the transmission time / transmission pause time adjustment unit determines the transmission pause time c ′ obtained by adjusting the transmission pause time c, thereby synchronizing with the operation cycle of the communication node on the reception side. However, instead of the transmission pause time c, the transmittable time b may be adjusted.

  In this case, the transmission time / transmission suspension time adjustment unit adjusts the transmittable time b, determines a transmittable time b 'that is shorter than the transmittable time b, and notifies the transmit time limit control unit. Then, the transmission time limit control unit controls the communication control unit according to the notified transmission available time b '.

  For example, the transmission time / transmission pause time adjustment unit may determine the transmittable time b ′ as follows.

  In this case, the transmission time / transmission suspension time adjustment unit may determine the transmittable time b ′ so as to satisfy the following expression (9), for example.

n (a + b ′ + c) = Tr−b′−a (9)
The transmission time / transmission pause time adjustment unit may obtain the transmission possible time b ′ by the following equation (10) when Tr> b. However, in the following formula (10), n is a natural number, and n is a value satisfying the following formula (11). In the following equation (11), ceil (x) is a round-up function. Further, it is assumed that b ′> 0.

  It should be noted that the minimum value of n applied to the following equation (10) is optimal among those satisfying the following equation (11).

b ′ = (Tr−a−n * (a + c)) / (n + 1) (10)
n> = ceil ((Tr−b) / (a + b + c)) (11)
Then, the transmission time / transmission suspension time adjustment unit may obtain the transmission possible time b ′ by the following equation (12) when Tr <= b.

b ′ = b (12)
(C-2) In each of the above embodiments, the carrier sense time a is used as one of the parameters for determining the transmission pause time c ′ and the transmittable time b ′. However, when the carrier sense time a is smaller than the transmission possible time b and the transmission pause time c, the carrier sense time a is set to 0 to simplify the processing, and the transmission pause time c ′ and the transmission possible time b ′. May be calculated.

(C-3) In each of the above embodiments, the transmission-side communication node has been described as adopting the LPL method. However, the transmission-side communication node may be configured not to adopt the LPL method.

(C-4) In the first embodiment, the transmission-side communication node and the reception-side communication node are described as having the same configuration, but the reception-side communication node 10-2 employs a conventional LPL system. It may be a communication node.

(C-5) In the second embodiment, the transmission-side communication node 10A-1 and the reception-side communication node 10A-2 have been described as having the same configuration, but the reception-side communication node 10A-2 has been conventionally used. The communication node adopting the LPL method may be applied with a means for notifying other communication nodes of the operation cycle Tr of the own node.

(C-6) In each of the above-described embodiments, the receiving communication node performs the activation operation in response to the Wakeup signal from the transmitting communication node. Also good. For example, a data frame having an arbitrary content may be transmitted from a transmission-side communication node to a reception-side communication node, and the reception side may be activated in response to reception of the data frame.

  Further, in each of the above embodiments, the information on the scheduled transmission time (information indicating the timing for transmitting the data frame) is inserted into the Wakeup signal itself transmitted by the communication node on the transmission side, and the communication node on the reception side receives the Wakeup Ack. You may make it start until the scheduled transmission time without returning a signal (a state in which data can be received).

  DESCRIPTION OF SYMBOLS 1 ... Communication system 10, 10-1, 10-2 ... Communication node, 101 ... Communication part, 102 ... Communication control part, 103 ... Communication data processing part, 104 ... Intermittent operation control part, 105 ... Timer, 106 ... Power supply 107: Wakeup signal processing unit, 108 ... Wakeup signal generation unit, 109 ... Transmission time limit control unit, 110 ... Transmission time / transmission pause time adjustment unit, 111 ... Adjacent node operation cycle storage unit, 112 ... Timer.

Claims (8)

When performing data transmission by wireless communication to the receiving-side wireless communication device that is in a data reception standby period in which data can be received by wireless communication at each intermittent operation cycle in the dormant state, the maximum data transmission period is set as the upper limit. For each data transmission period to be performed, in a wireless communication device that sets a data transmission stop period for stopping data transmission, a period longer than the data transmission stop minimum period,
Intermittent operation period information holding means for holding information on the intermittent operation period in the wireless communication device on the receiving side;
Data transmission period determining means for determining the data transmission stop period or the length of the data transmission period of the wireless communication device using information held in the intermittent operation cycle information holding means;
An operation state control unit that controls an operation state of the wireless communication device according to the determination of the data transmission period determination unit.   The data transmission period determining means is configured to stop data transmission of the wireless communication apparatus so that the timing of the data reception standby period of the receiving wireless communication apparatus and the timing of the data transmission stop period of the wireless communication apparatus do not overlap. The wireless communication apparatus according to claim 1, wherein a period or a data transmission period is determined.   When the intermittent operation cycle information holding unit does not hold information on the intermittent operation cycle in the reception-side wireless communication device, the data transmission period determining unit uses the random number value to transmit data of the wireless communication device. The wireless communication apparatus according to claim 1, wherein a stop period or a data transmission period is determined.   The wireless communication device according to any one of claims 1 to 3, further comprising an intermittent operation cycle notifying unit that notifies an intermittent operation cycle of the wireless communication device to other wireless communication devices in the vicinity.   5. The intermittent operation cycle information holding unit extracts and holds an intermittent operation cycle of the reception-side wireless communication device from information notified from the reception-side wireless communication device. The wireless communication device according to any one of the above. When performing data transmission by wireless communication to the receiving-side wireless communication device that is in a data reception standby period in which data can be received by wireless communication at each intermittent operation cycle in the pause state, the maximum data transmission period is set as the upper limit. For each data transmission period to be performed, a computer mounted on a wireless communication device that sets a data transmission stop period for stopping data transmission for a period equal to or longer than the data transmission stop minimum period,
Intermittent operation period information holding means for holding information on the intermittent operation period in the wireless communication device on the receiving side;
Data transmission period determining means for determining the data transmission stop period or the length of the data transmission period of the wireless communication device using information held in the intermittent operation cycle information holding means;
A wireless communication program that functions as an operation state control unit that controls an operation state of the wireless communication device according to the determination of the data transmission period determination unit.   A communication system comprising one or a plurality of wireless communication apparatuses according to claim 1. In a communication system comprising one or more first wireless communication devices and one or more second wireless communication devices,
Each of the first wireless communication devices is
When the wireless communication device is in a dormant state, set a data reception standby period in which data can be received by wireless communication every intermittent operation cycle,
Having intermittent operation cycle notifying means for notifying other wireless communication devices of the intermittent operation cycle of the wireless communication device;
6. A communication system, wherein the wireless communication device according to claim 5 is applied as each of the second wireless communication devices.

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