JP2022086324A - Terminal, method, and program - Google Patents

Abstract

To provide a terminal, a method, and a program that can simplify the configuration of a device, and extend the life of the device while improving packet reception accuracy.SOLUTION: A slave unit (terminal) 10 includes a transmitting/receiving unit (receiving unit) 12, a reception success/failure detection unit 113, and a waiting time window setting unit 118. The transmitting/receiving unit 12 receives packets periodically transmitted from a master unit. The reception success/failure detection unit 113 detects whether packet reception was successful or failed in a window period indicating a reception waiting period. The waiting time window setting unit 118 counts whether the packet reception was successful or failed while receiving a plurality of packets and sets width of the window period in packet reception next time or after based on the number of reception successful times and the number of reception failed times.SELECTED DRAWING: Figure 1

Description

The present invention relates to terminals, methods and programs.

With the development of IoT (Internet of Things) technology, the power consumption of wireless terminals is suppressed while the demand for services that collect and utilize information acquired by cameras and various sensors in remote areas is increasing. The need for longer life and more efficient operation is increasing more than ever before.

In Patent Document 1, the slave unit sets a time window for receiving packets periodically transmitted from the master unit, and suspends or stops the communication function other than the time window, thereby causing a terminal. The technology for extending the life of the window is disclosed. Here, the slave unit sets a first time window for receiving the packet at the time of the first communication. Then, the slave unit generates a second time window synchronized with the access timing of the master unit instead of the first time window from the reference time information of the packet received from the master unit and the reception timing of the packet. Further, the slave unit detects a deviation between the reception timing of the packet received from the master unit in the second time window and the generation timing of the second time window, and the second unit according to the detected deviation amount. Correct the generation timing of the time window.

Japanese Patent No. 4928864

In Patent Document 1, a time window that allows for fluctuations due to a deviation (error) of the reference clock between the master unit and the slave unit is generated. For that purpose, it is necessary to use the theoretical value calculated from the accuracy information of the clocks possessed by the master unit and the slave unit, or the measured value obtained by using another means in addition to the above-mentioned method. Then, when the former theoretical value is used, for example, the value of the margin included in the window becomes large because individual differences must be taken into consideration. Further, when the latter measured value is used, it is necessary to newly prepare a fluctuation measuring means. Therefore, there is a problem that the configuration of the device becomes complicated.

Further, in Patent Document 1, only fluctuations caused by clock deviation are assumed. However, in reality, fluctuations caused by other factors may naturally exist. Therefore, if the arrival timing of the packet is shifted outside the above-mentioned window period due to unexpected fluctuation, the packet cannot be received. That is, there is a problem that there is room for improvement in packet reception accuracy.

The present disclosure provides terminals, methods and programs that can extend the life of the device while simplifying the configuration of the device and improving the packet reception accuracy by solving such problems.

The terminal of the present disclosure includes a receiving unit that receives packets periodically transmitted from the master unit, and a reception success / failure detecting unit that detects whether or not the packet reception was successful or unsuccessful in the window period indicating the reception waiting period. , While receiving a plurality of the packets, the success or failure of the reception of the packet is counted, and the width of the window period in the reception of the next and subsequent packets based on the number of successful receptions and the number of failed receptions. It is equipped with a waiting time window setting unit for setting.

The method of the present disclosure is to receive a packet periodically transmitted from the master unit, to detect whether or not the reception of the packet is successful or unsuccessful in a window period indicating a reception waiting period, and to detect a plurality of the above. While receiving a packet, count whether the packet was successfully received or failed, and set the width of the window period for receiving the next and subsequent packets based on the number of successful receptions and the number of failed receptions. And, including.

The program of the present disclosure includes a process of receiving a packet periodically transmitted from a master unit, a process of detecting whether or not the packet has been successfully received in a window period indicating a reception waiting period, and a plurality of the above. A process that counts whether the packet was successfully received or failed while receiving the packet, and sets the width of the window period for the next and subsequent packet receptions based on the number of successful receptions and the number of failed receptions. And let the computer do it.

INDUSTRIAL APPLICABILITY According to the present disclosure, it is possible to provide a terminal, a method and a program capable of extending the life of the device while simplifying the configuration of the device and improving the packet reception accuracy.

It is a block diagram which shows the structure of the communication system which concerns on 1st Embodiment. It is a flowchart which shows the operation of the handset which concerns on 1st Embodiment. It is a block diagram which shows the structure of the communication system which concerns on 2nd Embodiment. It is a block diagram which shows the structure of the handset which concerns on 2nd Embodiment. It is a flowchart which shows the operation of the handset which concerns on 2nd Embodiment. It is a figure which shows the initial operation of the window period setting in the handset which concerns on 2nd Embodiment. It is a figure which shows the operation of reducing the window period in the handset which concerns on 2nd Embodiment. It is a figure which shows the operation of expanding the window period in the handset which concerns on 2nd Embodiment. It is a figure which shows the operation of skipping the window period in the handset which concerns on 2nd Embodiment. It is a block diagram which shows the hardware composition of a computer.

Hereinafter, specific embodiments to which the present disclosure is applied will be described in detail with reference to the drawings. In each drawing, the same elements are designated by the same reference numerals, and duplicate explanations will be omitted as necessary for the sake of clarity of explanation.

(First Embodiment)
First, the configuration of the communication system 1 according to the first embodiment will be described with reference to FIG. The communication system 1 includes a slave unit 10 and a master unit 20. The slave unit 10 or the master unit 20 is, for example, a wireless terminal capable of executing wireless communication such as a smartphone, a tablet, or a PC (Personal Computer), or a wired terminal capable of executing wired communication. The slave unit 10 wirelessly or wiredly communicates with the master unit 20, and communication between the slave unit 10 and the master unit 20 is performed at regular time intervals. The master unit 20 periodically transmits a packet to the slave unit 10. For example, the master unit 20 transmits either a life-and-death monitoring packet or a packet including various commands to the slave unit 10, and the slave unit 10 executes processing according to the type of the packet.

The slave unit 10 includes a transmission / reception unit (reception unit) 12, a reception success / failure detection unit 113, and a standby time window setting unit 118. The transmission / reception unit 12 receives packets periodically transmitted from the master unit. The reception success / failure detection unit 113 detects whether the packet has been successfully received or failed in the window period indicating the reception waiting period. The waiting time window setting unit 118 counts whether the packet has been successfully received or failed while receiving the plurality of the packets, and the next and subsequent packets are based on the number of successful receptions and the number of failed receptions. Sets the width of the window period for receiving.

Subsequently, the operation of the handset 10 according to the first embodiment will be described with reference to FIG.
First, the transmission / reception unit 12 receives the packets periodically transmitted from the master unit (step S11). The reception success / failure detection unit 113 detects whether the packet reception was successful or unsuccessful in the window period indicating the reception waiting period (step S12). Next, the waiting time window setting unit 118 counts whether the packet reception is successful or unsuccessful while receiving a plurality of packets, and is based on the number of successful receptions and the number of failed receptions from the next time onward. The width of the window period in receiving the packet is set (step S13).

The slave unit 10 according to the first embodiment does not need the clock information possessed by the master unit 20. Therefore, it is not necessary to use the theoretical value calculated from the clock accuracy information possessed by the master unit 20 and the slave unit 10, or the measured value obtained by using another means other than the above-mentioned method. Therefore, it is not necessary to consider the individual difference between the master unit 20 and the slave unit 10, and it is not necessary to newly prepare a fluctuation measuring means. Therefore, the configuration of the device can be simplified.
Further, the slave unit 10 can optimize the reception standby time while continuing to receive the packet by lengthening, shortening, or changing the window period according to the packet reception status of the slave unit 10. Therefore, even if the arrival timing of the packet is deviated from the above-mentioned window period due to the fluctuation, the packet arrival timing can be set in the window period according to the reception status in the next packet reception. Therefore, the packet reception accuracy can be improved.
Therefore, it is possible to simplify the configuration of the device and extend the life of the device while improving the packet reception accuracy.

(Second embodiment)
Subsequently, the configuration of the communication system 2 according to the second embodiment will be described with reference to FIG. As shown in FIG. 3, the communication system 2 includes a slave unit 10, a master unit 20, a management center 30, and a repeater 40.
The slave unit 10 communicates wirelessly or by wire with the master unit 20 or the repeater 40. The slave unit 10 includes, for example, a camera and various sensors to collect information. The master unit 20 communicates wirelessly or by wire with the slave unit 10 or the repeater 40. Further, the master unit 20 communicates wirelessly or by wire with the management center 30 via a communication line. The master unit 20 transmits, for example, the information collected by the slave unit 10 to the management center 30. In addition, the state of the slave unit 10 is periodically monitored for life and death. The management center 30 communicates wirelessly or by wire with the master unit 20 via a communication line. The management center 30 manages the communication system 2, for example, the information collected by the slave unit 10.

Subsequently, with reference to FIG. 3, the outline of the operation of the communication system 2 according to the second embodiment will be described.
As shown in FIG. 3, communication between the slave unit 10 and the master unit 20 is performed at regular time intervals. For example, when the image acquisition request from the management center 30 is generated, the master unit 20 transmits various instruction commands to the slave unit 10. If the image acquisition request from the management center 30 does not occur, the master unit 20 transmits the life-and-death monitoring packet of the slave unit 10 toward the slave unit 10. There are two types of packets transmitted from the master unit 20 to the slave unit 10: various commands and life-and-death monitoring, and the slave unit 10 executes processing according to the packet type.

Subsequently, the configuration of the slave unit 10 according to the second embodiment will be described with reference to FIG. As shown in FIG. 4, the slave unit 10 includes a control unit 11, a transmission / reception unit 12, a clock supply unit 13, and a power supply unit 14. The control unit 11 includes a packet communication control unit 111, a reception time shift detection unit 112, a reception success / failure detection unit 113, a reception electric field strength detection unit 114, a reception success / failure comparison unit 115, a power supply voltage monitoring unit 116, a storage unit 117, and a standby time window. It includes a setting unit 118 and an operation mode determination unit 119 (hereinafter, each functional unit).

The transmission / reception unit 12 terminates the physical signal to and from the master unit 20. As a receiving unit, the transmitting / receiving unit 12 supplies the received packet received from the master unit to the control unit 11 inside the terminal. Further, the transmission / reception unit 12 transmits the transmission packet received from the control unit 11 to the master unit 20 as the transmission unit. Further, the transmission / reception unit 12 waits for signal reception according to the instruction of the packet communication control unit 111.

The packet communication control unit 111 executes the attachment / detachment of the header of the packet exchanged with the transmission / reception unit 12 and the reception / standby instruction to the transmission / reception unit 12. Further, the packet communication control unit 111 transmits / receives information necessary for packet communication control to / from each functional unit of the control unit 11.

The reception time deviation detection unit 112 clocks the time difference between the reference time previously agreed between the slave unit 10 and the master unit 20 and the reception time when the packet communication control unit 111 receives the packet. The unit 13 is used as a clock source for detection based on the internal time held by the terminal itself, and the detected time difference is supplied to the standby time window setting unit 118.

The reception success / failure detection unit 113 uses the expected reception time set by the standby time window setting unit 118, the reception standby window period information, the reception notification information from the packet communication control unit 111, and the internal time information to receive the packet within the standby time. Detects the success or failure of. The reception success / failure detection unit 113 notifies the reception success / failure comparison unit 115 of the detection result.

The received electric field strength detection unit 114 extracts the electric field strength information stored in the RSSI (Received Signal Strength Indication) field at the time of packet reception from the header information received from the packet communication control unit 111, and stores the extracted value 117. Store in. Then, the received electric field strength detecting unit 114 compares the extracted value with the received electric field strength threshold value stored in the storage unit 117, and notifies the reception success / failure comparison unit 115 of the comparison result.

The reception success / failure comparison unit 115 updates the value of the reception success count or the reception failure count in the current window period stored in the storage unit 117 according to the notification from the reception success / failure detection unit 113. The reception success / failure comparison unit 115 compares the updated value with the threshold value of each number of times stored in the storage unit 117, and notifies the waiting time window setting unit 118 of the window period change request based on the comparison result. Further, the reception success / failure comparison unit 115 updates the number of consecutive reception failures when the reception of the packet in the previous window period and the reception of the packet in the current window period fail in succession, and the updated value and the storage unit. The threshold value stored in 117 is compared, and the reception standby skip request is notified to the waiting time window setting unit 118 based on the comparison result. Here, the value of the threshold value to be compared with the number of continuous reception failures can be changed based on the comparison result in the received electric field strength detecting unit 114. The waiting time window setting unit 118, which will be described later, may have the function of the reception success / failure comparison unit 115.

The power supply voltage monitoring unit 116 monitors the remaining battery level of the slave unit 10 according to the voltage level by the notification from the power supply unit 14. The power supply voltage monitoring unit 116 compares the notified voltage value with the power supply voltage threshold value stored in the storage unit 117, and notifies the standby time window setting unit 118 of the comparison result.
The storage unit 117 stores the holding of each parameter necessary for setting the expected reception time and the window period, the reference of the value in response to the request of each functional unit, and the update process.

The waiting time window setting unit 118 calculates the expected reception time of the next packet based on the time difference information input from the reception time deviation detection unit 112, and is a window which is the next packet reception waiting time including the expected reception time. Set the period. Further, the waiting time window setting unit 118 refers to the storage unit 117 and determines the window period according to the window period change request input from the reception success / failure comparison unit 115. Further, the waiting time window setting unit 118 skips the window period setting a predetermined number of times in the next and subsequent packet receptions in accordance with the reception waiting skip request input from the reception success / failure comparison unit 115. Then, the waiting time window setting unit 118 notifies the packet communication control unit 111 of the information of the expected reception time and the reception waiting window period obtained by the processing up to this point.

The operation mode determination unit 119 determines whether the type of the packet received from the master unit 20 is a life-and-death monitoring packet or a packet including various commands. When the operation mode determination unit 119 receives the life-and-death monitoring packet from the master unit 20, the operation mode determination unit 119 notifies the packet communication control unit 111. The packet communication control unit 111 causes the transmission / reception unit 12 to transmit an ACK (ACKnowledgement) message to the master unit 20. Then, the operation mode determination unit 119 puts its own machine to sleep. On the other hand, when the operation mode determination unit 119 receives various commands from the master unit 20, the operation mode determination unit 119 executes processing according to the instruction of the command and does not sleep until the sleep instruction comes.
The clock supply unit 13 provides a function as a clock source of the slave unit 10.
The power supply unit 14 supplies the power required to drive the slave unit 10 and notifies the power supply voltage monitoring unit 116 of the remaining battery level.

Subsequently, the operation of the handset 10 according to the second embodiment will be described with reference to FIG. More specifically, the operation executed when the slave unit 10 receives the packet from the master unit 20 will be described.
As shown in FIG. 5, first, the packet communication control unit 111 of the slave unit 10 receives a packet from the master unit 20 via the transmission / reception unit 12 (step S101). The packet communication control unit 111 supplies the packet reception time to the reception time deviation detection unit 112 and the reception success / failure detection unit 113.

Next, the reception time deviation detection unit 112 detects the reception time deviation (step S102). Specifically, the reception time deviation detection unit 112 determines the time difference between the reference time previously agreed between the slave unit 10 and the master unit 20 and the reception time when the packet communication control unit 111 receives the packet. Is detected. The reception time deviation detection unit 112 supplies the detected time difference to the standby time window setting unit 118.

Next, the reception success / failure detection unit 113 detects the success / failure of packet reception during the window period (step S103). The reception success / failure detection unit 113 acquires the reception time when a packet is received from the packet communication control unit 111. The reception success / failure detection unit 113 detects whether or not the reception time of the packet is included in the window period, which is the current reception waiting period stored in the storage unit 117, and detects the success / failure of packet reception. The reception success / failure detection unit 113 notifies the reception success / failure comparison unit 115 of the detection result (reception success or reception failure).

Next, the received electric field strength detecting unit 114 acquires the received electric field strength (step S104). The received electric field strength detecting unit 114 compares the received electric field strength acquired in the current packet reception with the received electric field strength threshold value stored in the storage unit 117, and notifies the reception success / failure comparison unit 115 of the comparison result.

Next, the reception success / failure comparison unit 115 counts the number of successful packet receptions, the number of reception failures, or the number of continuous reception failures (step S105). Specifically, the reception success / failure comparison unit 115 updates the number of successful receptions stored in the storage unit 117 when the packet is successfully received in the current window period according to the notification of the detection result from the reception success / failure detection unit 113. do. Further, when the reception success / failure comparison unit 115 fails to receive the packet, the reception failure number of times stored in the storage unit 117 is updated. Further, when the reception success / failure comparison unit 115 continuously fails to receive the packet in the previous window period and the packet reception in the current window period, the reception success / failure comparison unit 115 updates the number of continuous reception failures stored in the storage unit 117.

Next, the reception success / failure comparison unit 115 compares the number of packet reception successes, the number of reception failures, and the number of continuous reception failures with the threshold value (step S106). Specifically, when the value of the number of successful receptions or the number of failed receptions after the update reaches the threshold value corresponding to each number stored in the storage unit 117, the reception success / failure comparison unit 115 waits for the window period change request. Notify the window setting unit 118. Further, when the value of the number of continuous reception failures after the update reaches the threshold value stored in the storage unit 117, the reception success / failure comparison unit 115 notifies the waiting time window setting unit 118 of the reception standby skip request. Here, when the reception strength when the packet is received this time is higher than the reception strength when the packet was received last time, the reception success / failure comparison unit 115 reduces the threshold value to be compared with the number of continuous reception failures. Further, when the reception strength when the packet is received this time is lower than the reception strength when the packet was received last time, the reception success / failure comparison unit 115 increases the threshold value to be compared with the number of continuous reception failures.

Next, the waiting time window setting unit 118 sets the expected reception time in the next packet reception (step S107). Specifically, the waiting time window setting unit 118 acquires the time difference information from the reception time deviation detection unit 112. The standby time window setting unit 118 sets the time obtained by adding the time difference information to the reference time preset in the next packet reception with the master unit 20 as the expected reception time for receiving the packet from the master unit 20 next time. do.

The waiting time window setting unit 118 sets the window period for the next packet reception (step S108). Specifically, the waiting time window setting unit 118 sets the next window period including the set expected reception time. Here, when the waiting time window setting unit 118 receives a window period change request from the reception success / failure comparison unit 115, the waiting time window setting unit 118 refers to the storage unit 117 in accordance with the window period change request, and changes the width of the window period in the next packet reception. do. For example, the waiting time window setting unit 118 shortens the width of the window period by a predetermined period when the number of successful receptions reaches the threshold value, and increases the width of the window period by a predetermined period when the number of failed receptions reaches the threshold value. do. Further, when the waiting time window setting unit 118 receives the reception waiting skip request from the reception success / failure comparison unit 115, the waiting time window setting unit 118 skips the window period setting a predetermined number of times in the next and subsequent packet receptions in accordance with the reception waiting skip request. For example, when the number of consecutive reception failures reaches the threshold value, the waiting time window setting unit 118 skips the setting of the window period by a predetermined number of times in the next and subsequent packet receptions.

Here, the detailed method of setting the expected reception time and the window period in the standby time window setting unit 118 will be described later in FIG. 6-9.

Then, the waiting time window setting unit 118 notifies the packet communication control unit 111 of the information of the expected reception time and the window period obtained by the processing up to this point. The packet communication control unit 111 executes a reception standby instruction to the transmission / reception unit 12 according to the notification. At this time, the transmission / reception unit 12 executes reception standby from the master unit 20 according to the instructed expected reception time and the window period.

Next, the operation mode determination unit 119 determines the operation mode (step S109). The operation mode determination unit 119 determines whether the type of the packet received from the master unit 20 is a life-and-death monitoring packet or a packet including various commands. When the operation mode determination unit 119 receives the life-and-death monitoring packet from the master unit 20, the operation mode determination unit 119 notifies the packet communication control unit 111. The packet communication control unit 111 causes the transmission / reception unit 12 to transmit an ACK message to the master unit 20. Then, the operation mode determination unit 119 puts its own machine to sleep. On the other hand, when the operation mode determination unit 119 receives various commands from the master unit 20, the operation mode determination unit 119 executes processing according to the instruction of the command and does not sleep until the sleep instruction comes.

Subsequently, the operation of setting the expected reception time and the window period in the handset 10 according to the second embodiment will be described in detail with reference to FIGS. 6-9. The slave unit 10 learns the above-mentioned window period and expected reception time each time the slave unit 10 and the master unit 20 communicate with each other. Here, the slave unit 10 performs the initial operation in the learning in the first packet reception standby from the start of communication with the master unit 20. The slave unit 10 performs learning by the process as shown in FIG. 5 in the second and subsequent packet reception standbys.

First, with reference to FIG. 6, the initial operation of the packet reception standby in the slave unit 10 according to the second embodiment will be described.
For the slave unit 10, the master unit 20 is arranged to wake up at 00 seconds per hour, for example, and transmit a packet. The slave unit 10 also wakes up at 00 seconds for the first packet reception standby with the reference time of 00 seconds per hour, which is common to that of the master unit 20. The slave unit 10 sets the “default waiting time # 1” stored in the storage unit 117 for the period of the first packet reception waiting period. The "default waiting time # 1" can be set to any value by tuning. The slave unit 10 repeatedly waits for reception in the "default standby time # 1" in accordance with the reference time until the packet from the master unit 20 can be received. Then, when the slave unit 10 receives the packet from the master unit 20, it predicts the second expected reception time based on the reception time at that time, and sets a width before and after that to perform reception standby. Set the period, that is, the window period. Here, the slave unit 10 sets a "default standby time # 2" shorter than the "default standby time # 1" in the second reception standby period.

The storage unit 117 stores in advance the "default waiting time # 1" set in the above-mentioned first packet reception standby and the "default waiting time # 2" set in the second packet reception standby. Further, the storage unit 117 sets the "waiting time window period change width" and "waiting time window period change width" set in the third and subsequent packet reception waits as parameters that can have a desired value as a fixed value by tuning. "Maximum value", "Minimum value of standby time window period", "Reception success count threshold", "Reception failure count threshold", "Power supply voltage threshold", "Received electric field strength threshold", "Continuous reception failure count threshold # 1" , "Continuous reception failure count threshold # 2" and "Reception standby postponement count" are stored in advance. Further, the storage unit 117 has "received electric field strength at the time of the previous reception" as a parameter updated by the function unit in charge each time a packet is received, and "a parameter updated periodically regardless of whether or not the packet has been received". The power supply voltage at the latest reference time, the number of successful receptions in the set window period, the number of reception failures in the set window period, and the number of continuous reception failures are stored in advance. The usage of each parameter will be described later.

As shown in FIG. 6, the standby time window setting unit 118 of the slave unit 10 waits for the above-mentioned "default standby time # 1" stored in the storage unit 117 at the time of the first wake-up in the first packet reception standby. It is set as a period, that is, a window period W11. After that, the packet communication control unit 111 wakes up at 00 seconds per hour until the first packet is received, and waits for packet reception only during the "default waiting time # 1" period. Then, the packet communication control unit 111 sleeps when the "default waiting time # 1" ends without the slave unit 10 receiving the packet, wakes up again at the next 00 seconds, and "default waiting time # 1". The operation of waiting for packet reception is repeated.

When the packet communication control unit 111 receives a packet from the master unit 20 during the reception standby period of the “default standby time # 1”, the packet communication control unit 111 notifies the reception time deviation detection unit 112 of the reception time value based on the internal time information. do. The reception time deviation detection unit 112 detects the time difference between the reference time (00 seconds) and the reception time. In FIG. 6, the packet received by the slave unit 10 from the master unit 20 is defined as P, and the packet reception time is indicated by a dashed line. Specifically, as shown in FIG. 6, the reception time shift detection unit 112 has the first packet reception time of xx: yy + 1: aa with respect to the reference time of every hour and minute of xx: yy + 1: 00. In this case, the time difference between the reference time and the reception time is set to 00:00: aa. Then, the reception time deviation detection unit 112 notifies the waiting time window setting unit 118 of the value of the time difference.

Next, the waiting time window setting unit 118 sets the time xx: yy + 2:00 + aa, which is the sum of the reference time xx: yy + 2:00 and the time difference value 00:00: aa in the second packet reception standby, for the second time. The expected reception time for packet reception. Then, the waiting time window setting unit 118 sets the second reception waiting period by providing a width by "default waiting time # 2" before and after the expected reception time. Here, assuming that the value of the "default waiting time # 2" is α, as shown in FIG. 6, between the time xx: yy + 2: aa−α and xx: yy + 2: aa + α (xx: yy + 2: aa ± α). The second reception standby will be performed. Here, the period during which the second reception standby is performed is defined as the window period W12. However, the window period W12 is the maximum standby time when a packet is not received within the period.

When the slave unit 10 receives a packet during the period, the slave unit 10 performs processing according to the packet type and the command included in the packet, and then shifts to the sleep state. Therefore, when the slave unit 10 receives a packet, the slave unit 10 may continue the operation beyond the reception standby period, or conversely, may shift to the sleep state without waiting for the end of the period. However, the slave unit 10 continues to operate only when it is necessary for communication with the master unit 20, and in the case of alive monitoring, after receiving the slave unit 10, an ACK message is transmitted to the master unit 20 immediately. Power consumption is kept to the minimum necessary because it goes to sleep.

Subsequently, the learning operation of the packet reception standby in the slave unit 10 according to the second embodiment will be described with reference to FIGS. 7-9.
In the second and subsequent reception standbys, the reception success / failure detection unit 113 detects whether or not a packet can be received within the set period for the window of the reception standby time currently set for each reception standby. Then, the reception success / failure detection unit 113 notifies the reception success / failure comparison unit 115 of the determination result. When the packet can be received, the reception success / failure comparison unit 115 refers to the parameter "number of successful receptions in the set window period" stored in the storage unit 117, and the value of "number of successful receptions in the set window period". Add 1 to update. On the other hand, when the packet cannot be received, the reception success / failure comparison unit 115 refers to the parameter "number of reception failures in the set window period" stored in the storage unit 117, and "the number of reception failures in the set window period". 1 is added to the value of "" to update. Then, the reception success / failure comparison unit 115 compares the value of the updated “reception success count in the set window period” with the fixed parameter “reception success count threshold” stored in the storage unit 117. Further, the reception success / failure comparison unit 115 compares the value of the updated “number of reception failures in the set window period” with the value of the fixed parameter “reception failure number threshold” stored in the storage unit 117.

As a result of the comparison, the value of "Reception success count in the set window period" is smaller than the value of "Reception success count threshold", or the value of "Reception failure count in the set window period" is "Reception failure count". If it is smaller than the value of "threshold value", the reception success / failure comparison unit 115 ends the process as it is, and performs the same process again at the next wake-up time.

As a result of the comparison, the value of "Reception success count in the set window period" is equal to the value of "Reception success count threshold", or the value of "Reception failure count in the set window period" is "Reception failure count threshold". When the value is equal to the value of "", the reception success / failure comparison unit 115 notifies the waiting time window setting unit 118 of the window period change request. The waiting time window setting unit 118 changes the window period of the reception waiting period set at the next wake-up according to the window period change request. Specifically, when the value of "the number of successful receptions in the set window period" is equal to the value of the "threshold value of the number of successful receptions", the slave unit 10 reduces the window period as shown in FIG. 7, which will be described later. When the value of "the number of reception failures in the set window period" is equal to the value of the "reception failure number threshold", the slave unit 10 extends the window period as shown in FIG. 8 to be described later. The step size for changing each window period at this time is determined by the above-mentioned fixed parameter "waiting time window period change width". The upper limit of the window period is determined by the "maximum value of the waiting time window period", and the lower limit value is determined by the "minimum value of the waiting time window period". Then, when the window period reaches these values, it cannot be made longer or shorter. That is, the value can be maintained even when the change condition is satisfied.

Subsequently, with reference to FIG. 7, the details of the learning operation for reducing the window period in the slave unit 10 according to the second embodiment will be described.
As shown in FIG. 7, when the packet can be received from the master unit 20, the reception success / failure comparison unit 115 of the slave unit 10 adds 1 to the value of the “number of successful receptions in the set window period” of the storage unit 117. And update. As shown in FIG. 7, the slave unit 10 succeeds in receiving the N-2th packet, the N-1th packet, and the Nth packet. Then, in the Nth packet reception, the value of "the number of successful receptions in the set window period" becomes equal to the value of the "threshold value of the number of successful receptions". In that case, the reception success / failure comparison unit 115 notifies the waiting time window setting unit 118 of the result. The waiting time window setting unit 118 sets the window period W22, which is a reduction of the window period W21, in the packet reception waiting period in the N + 1th packet reception according to the notified result. Specifically, the waiting time window setting unit 118 sets the reception waiting period between the times xx: yy + 2: aa−α and xx: yy + 2: aa + α (xx: yy + 2: aa ± α) in the Nth packet reception. It is set. Then, by reducing the window period W21 to the window period W22, the waiting time window setting unit 118 sets the reception waiting period from the time xx: yy + 3: aa- (α-β) to xx: in the N + 1th packet reception. It is set between yy + 3: aa + (α-β) (xx: yy + 3: aa ± (α-β)). β is a fixed parameter “change width of the waiting time window period” stored in the storage unit 117, and is represented by an integer of 0 or more.

Subsequently, with reference to FIG. 8, the details of the learning operation for expanding the window period in the handset 10 according to the second embodiment will be described.
When the packet cannot be received from the master unit 20, the reception success / failure comparison unit 115 of the slave unit 10 adds 1 to the value of the "number of reception failures in the set window period" of the storage unit 117 to update. As shown in FIG. 8, the slave unit 10 fails to receive the M-2nd packet, the M-1st packet, and the Mth packet. Then, in the Mth packet reception, the value of "the number of reception failures in the set window period" becomes equal to the value of the "reception failure number threshold". In that case, the reception success / failure comparison unit 115 notifies the waiting time window setting unit 118 of the result. The waiting time window setting unit 118 sets the window period W32, which is an extension of the window period W31, to the packet reception waiting period in the M + 1th packet reception according to the notified result. Specifically, the waiting time window setting unit 118 sets the reception waiting period between the times xx: yy + 2: aa−α and xx: yy + 2: aa + α (xx: yy + 2: aa ± α) in the Mth packet reception. It is set. Then, by expanding the window period W31 to the window period W32, the waiting time window setting unit 118 sets the reception waiting period from the time xx: yy + 3: aa− (α + β) to xx: yy + 3: in the M + 1th packet reception. It is set between aa + (α + β) (xx: yy + 3: aa ± (α + β)). β is a fixed parameter “change width of the waiting time window period” stored in the storage unit 117, and is represented by an integer of 0 or more.

After that, the slave unit 10 succeeds in receiving the M + 1th packet. The reception time deviation detection unit 112 of the slave unit 10 determines the reference time and the reception time when the M + 1th packet reception time is xx: yy + 3: bb with respect to the reference time of every hour and minute xx: yy + 3:00. The time difference of is 00:00:bb. The waiting time window setting unit 118 receives the M + second packet at the time xx: yy + 4:00 + bb, which is the sum of the reference time xx: yy + 4:00 and the time difference value 00:00:bb in the M + second packet reception standby. Set as the expected time. Then, the waiting time window setting unit 118 sets a width of α + β before and after the expected reception time to set the M + second reception waiting period. Then, the slave unit 10 will perform M + second reception standby between the time xx: yy + 4: bb- (α + β) and xx: yy + 2: bb + (α + β) (xx: yy + 2: bb ± (α + β)). ..

Therefore, the slave unit 10 can optimize the reception standby time while continuing to receive the packet by lengthening or shortening the reception standby time according to the packet reception status.

Subsequently, with reference to FIG. 9, the learning operation for skipping the reception standby in the slave unit 10 according to the second embodiment will be described.
After waking up for the first time, the slave unit 10 operates by the above-mentioned processing, but the battery may not be charged using the solar panel due to deterioration of sunshine conditions, flying of a shield, or the like. In such a case, even if the above-mentioned processing in the slave unit 10 is properly performed, the remaining battery level will decrease over time, and the availability of the system will be impaired. In particular, when stable communication cannot be expected due to deterioration of radio wave conditions, the number of reception failures increases, and there is a risk that the standby time window will be operated for a long time when it reaches the "maximum value of the standby time window period". be.

In order to avoid the above-mentioned situation when the packet has not been received for a long time, the reception success / failure comparison unit 115 receives the first time in addition to the "reception failure number threshold" for each window period currently set. Count the number of consecutive reception failures from failure. Here, the reception success / failure comparison unit 115 continuously counts beyond the set range of each window period updated by the learning operation. Specifically, as shown in FIG. 9, in the period T1, the reception success / failure comparison unit 115 counts the number of consecutive reception failures in the window period W41. In the period T2, the reception success / failure comparison unit 115 counts the number of continuous reception failures in the window period W42. Here, in the window period W42, the window period is expanded from the window period W41 because the “reception failure number in the set window period” reaches the “reception failure number threshold” in the window period W41. In the period T3, the reception success / failure comparison unit 115 counts the number of continuous reception failures in the window period W41 and the window period W42 beyond the set range of the window period.

Then, the reception success / failure comparison unit 115 notifies the waiting time window setting unit 118 of the reception standby skip request when the number of continuous reception failures reaches the “continuous reception failure number threshold”. The waiting time window setting unit 118 skips the reception waiting from the next time onward by the "number of times of waiting for reception". After skipping, the operation of performing reception standby (recovery standby) again from the reference time aa: bb: 00 at the "default standby time # 1" is repeated until the packet is received again.

At this time, there are two possible patterns: a case where the packet does not come suddenly even though the radio wave condition at the time of the previous reception was good, and a case where the packet finally stops coming even though the radio wave condition was originally bad. In the former case, it can be seen that packets are not coming at a relatively early stage rather than timing lag, but in the latter case, it can be judged whether it can be considered that packets are completely stopped without waiting for a while. difficult.

Therefore, the above-mentioned "threshold value for the number of continuous reception failures" is switched according to the value of the previous received electric field strength. Specifically, after the reception success / failure comparison unit 115 starts counting reception failures, the reception electric field strength detection unit 114 refers to the value of "reception electric field strength at the time of previous reception" stored in the storage unit 117. , This is also compared with the "received electric field strength threshold" stored in the storage unit 117, and the comparison result is notified to the reception success / failure comparison unit 115. When the reception electric field strength exceeds the threshold value, the reception success / failure comparison unit 115 sets the “continuous reception failure count threshold # 1”, and when the reception electric field strength falls below the threshold value, the “continuous reception failure count threshold # 2” is set. It is applied as a threshold for the number of reception failures. Here, if the "continuous reception failure count threshold # 1" is set small and the "continuous reception failure count threshold # 2" is set large, it is possible to determine the case where packets do not come completely for each of the above two patterns, and then. It is possible to properly shift to the recovery standby operation of.

Further, the number of times the reception standby is skipped between the recovery standbys is stored in advance in the storage unit 117 as the "reception standby suspension number". Then, after receiving the notification from the reception success / failure comparison unit 115 that the number of continuous reception failures has reached the threshold value, the standby time window setting unit 118 skips the reception standby from the next time onward with reference to this value, and waits for recovery. The instruction is output to the packet communication control unit 111.

By this process, the slave unit 10 does not continue to extend the window period endlessly even if the packet has not been received continuously, and the frequency of reception standby is reduced when a predetermined number of reception failures occur, and the power consumption is reduced. You can use the reference time and the first window to wait for reception to be restored on a regular basis while reducing consumption.

Further, the slave unit 10 may periodically monitor the power supply voltage for notifying the remaining battery level and switch the operation according to the magnitude between the threshold value and the preset threshold value. For example, the power supply voltage monitoring unit 116 checks the value of the power supply voltage at each reference time, and if this falls below the "power supply voltage threshold value" stored in the storage unit 117, the information is sent to the standby time window setting unit 118. Notice. Then, the standby time window setting unit 118 may switch the learning operation of the window to a mode specialized for low power consumption. When the slave unit 10 shifts to this mode, for example, among the learning operations for window optimization, only the window enlargement processing when the number of reception failures exceeds the threshold value is stopped and the monitoring of the power supply voltage is continued. .. Then, when the power supply voltage value exceeds the threshold value, the slave unit 10 returns the learning operation to the mode before the change again. By doing so, the slave unit 10 can suppress power consumption associated with the learning operation while receiving packets as much as possible when the remaining battery level of the slave unit 10 is low.

Therefore, the communication system 2 according to the second embodiment has the following effects in addition to the effects according to the communication system 1 according to the first embodiment.
Patent Document 1 does not mention the case where the packet cannot be received within the short window period, but in such a situation, the window period must be extended to the extent that the packet can be received again. .. If the unreceived packet is caused by the deviation of the reception timing outside the window period, this countermeasure can be used. However, for example, if the packet is not delivered due to a decrease in the signal strength in wireless communication, the window is displayed. Even if the period is extended, the packet cannot be received until the radio wave condition is improved. On the contrary, if the packet is not received continuously, the process of extending the window period is repeated, and finally the same as the first communication, or it. There is a problem that the above unnecessary power consumption continues to occur.
In the communication system 2, if the slave unit 10 cannot receive a packet from the master unit 20, it is determined based on the latest received electric field strength information, and the frequency of waking up is reduced to suppress power consumption. You can wait for time to recover.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit.
As another embodiment of the present invention, even in the configuration in which the slave unit 10 in FIG. 3 is replaced with a wired terminal, the parameter of the received electric field strength is not used, and the mode switching process using this as a determination condition is stopped. In the same way, the life of the terminal can be extended. Further, even when the repeater 40 is sandwiched between the master unit 20 and the slave unit 10, the master unit 20 in the above-described embodiment is used as a slave unit, and the slave unit 10 is used as a master unit. The repeater 40 performs each of these operations. By doing so, it is possible to optimize the power consumption of the master unit 20 and the repeater 40, and the repeater 40 and the slave unit 10 while maintaining the same parent-child relationship.

<Hardware configuration>
Subsequently, an example of the hardware configuration of the computer according to the slave unit 10 will be described with reference to FIG. In FIG. 10, the computer has a processor 1001 and a memory 1002. The processor 1001 may be, for example, a microprocessor, an MPU (Micro Processing Unit), or a CPU (Central Processing Unit). Processor 1001 may include a plurality of processors. The memory 1002 is composed of a combination of a volatile memory and a non-volatile memory. The memory 1002 may include storage located away from the processor 1001. In this case, the processor 1001 may access the memory 1002 via an I / O interface (not shown).

Further, each device in the above-described embodiment is composed of hardware and / or software, and may be composed of one hardware or software, or may be composed of a plurality of hardware or software. The function (processing) of each device in the above-described embodiment may be realized by a computer. For example, a program for performing the method in the embodiment may be stored in the memory 1002, and each function may be realized by executing the program stored in the memory 1002 on the processor 1001.

These programs can be stored and supplied to a computer using various types of non-transitory computer readable media. Non-temporary computer-readable media include various types of tangible storage media. Examples of non-temporary computer-readable media include magnetic recording media (eg, flexible disks, magnetic tapes, hard disk drives), optomagnetic recording media (eg, optomagnetic disks), CD-ROMs (Read Only Memory), CD-Rs. Includes CD-R / W, semiconductor memory (eg, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random Access memory)). The program may also be supplied to the computer by various types of transient computer readable media. Examples of temporary computer readable media include electrical, optical, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

1 Communication system 2 Communication system 10 Slave unit (terminal)
11 Control unit 12 Transmission / reception unit (reception unit)
13 Clock supply unit 14 Power supply unit 20 Master unit 30 Management center 40 Repeater 111 Packet communication control unit 112 Reception time deviation detection unit 113 Reception success / failure detection unit 114 Reception field strength detection unit 115 Reception success / failure comparison unit 116 Power supply voltage monitoring unit 117 Storage Unit 118 Standby time window setting unit 119 Operation mode determination unit 1001 Processor 1002 Memory

Claims (9)

A receiver that receives packets periodically transmitted from the master unit,
A reception success / failure detection unit that detects whether or not the packet was successfully received in the window period indicating the reception waiting period, and
While receiving a plurality of the packets, the success or failure of the reception of the packet is counted, and the width of the window period in the reception of the next and subsequent packets is calculated based on the number of successful receptions and the number of failed receptions. A terminal equipped with a waiting time window setting unit to be set. The waiting time window setting unit shortens the width of the window period when the number of successful receptions reaches the first threshold value, and the window when the number of failed receptions reaches the second threshold value. The terminal according to claim 1, wherein the width of the period is extended by a predetermined period. The waiting time window setting unit counts the number of consecutive reception failures when the reception of the packet in the previous window period and the reception of the packet in the current window period fail in succession, and is based on the number of consecutive reception failures. The terminal according to claim 1 or 2, which skips the reception waiting of the next and subsequent packets a predetermined number of times. The terminal according to claim 3, wherein the waiting time window setting unit skips the reception waiting of the next and subsequent packets a predetermined number of times when the number of consecutive reception failures reaches the third threshold value. When the reception strength when the packet is received this time is higher than the reception strength when the packet was received last time, the waiting time window setting unit reduces the third threshold value and receives the packet when the packet was received last time. The terminal according to claim 4, wherein when the reception strength when the packet is received this time is lower than the strength, the third threshold value is increased. Any of claims 3 to 5, wherein the waiting time window setting unit skips the reception waiting of the next and subsequent packets a predetermined number of times when the packet cannot be received from the master unit in the window period set after skipping a predetermined number of times. The terminal described in item 1. The terminal according to any one of claims 1 to 6, further comprising a transmission unit that transmits information acquired by a sensor to the master unit according to an instruction included in the received packet. Receiving packets periodically transmitted from the master unit and
To detect whether reception of the packet was successful or unsuccessful in the window period indicating the reception waiting period, and
While receiving a plurality of the packets, the success or failure of the reception of the packet is counted, and the width of the window period in the reception of the next and subsequent packets is calculated based on the number of successful receptions and the number of failed receptions. How to set and include. Processing to receive packets periodically transmitted from the master unit,
A process for detecting whether or not the packet was successfully received in the window period indicating the reception waiting period, and
While receiving a plurality of the packets, the success or failure of the reception of the packet is counted, and the width of the window period in the reception of the next and subsequent packets is calculated based on the number of successful receptions and the number of failed receptions. A program that causes a computer to execute the processing to be set.

Images