JP7292332B2 - Slave station device and master station device - Google Patents

Description

The present invention relates to a slave station device and a master station device, and more particularly to a technique for transmitting data from a slave station device to a master station device.

Research and development is being conducted on a communication system that includes a master station device and a plurality of slave station devices, and in which each slave station device wirelessly transmits data to the master station device. In such a communication system, as shown in Patent Documents 1 to 4 below, each slave station device is equipped with a sensor for detecting a certain physical quantity, and sensor data indicating the detected value of the sensor is sent to the master station device. There are wirelessly transmitted data collection systems.

JP 2006-140823 A JP 2014-107762 A JP 2015-26949 A WO2016/170607

In the data collection system, there is a possibility that sensor data from a plurality of child station devices will be sent to the master station device in overlapping time zones. Therefore, in the systems described in Patent Documents 1 to 4, the data transmission time period of each slave station is determined so as not to cause such data collision. However, in the systems described in Patent Documents 1, 2, and 4, it is conceivable that the processing of the master station device becomes complicated, such as the master station device allocating data transmission time slots to a plurality of slave station devices. . In the system described in Patent Literature 3, communication initialization for determining the communicable time of the slave station device is started with the processing of the master station device as a trigger, and the degree of freedom of processing executed by the slave station device is limited. can be considered.

SUMMARY OF THE INVENTION It is an object of the present invention to avoid data collision with simple processing in a system in which data is transmitted from a plurality of slave station devices to a master station device.

According to the present invention, in a slave station device that transmits data to a master station device, timing request information including its own identification information is transmitted to the master station device, and the master station device transmits timing request information according to the timing request information. receiving setting information, setting its own transmission slot on the time axis based on the time information and order information included in the timing setting information, and indicates a transmission order determined for other different child station devices, and the child station device transmits the data in a predetermined transmission cycle using the transmission slot as a reference for transmission timing , and the other child station device The data is transmitted to the master station device directly or via relay of the station device, the timing setting information includes a relay stage upper limit value determined for the slave station device, and the slave station device and determining the time length of the transmission slot based on the upper limit value of the number of relay stages .

Preferably, the timing setting information includes a transmission retry count upper limit value determined for the slave station device, and the slave station device determines the time length of the transmission slot based on the transmission retry count upper limit value. to decide .

Further, according to the present invention, in a slave station device that transmits data to a master station device, timing request information including its own identification information is transmitted to the master station device, and the master station device transmits according to the timing request information. and sets its own transmission slot on the time axis based on the time information and order information included in the timing setting information, and the order information is obtained from the slave station apparatus and the slave station apparatus indicates a transmission order determined for other slave station devices different from the device, and the slave station device transmits the data in a predetermined transmission cycle using the transmission slot as a reference for transmission timing, and transmits the data at the timing The setting information includes a transmission retry count upper limit value determined for the slave station device , and the slave station device determines the time length of the transmission slot based on the transmission retry count upper limit value. and

Desirably, the sleep state is entered between the first transmission of the data and the next transmission of the data.

Further, according to the present invention, when a parent station apparatus receives timing request information transmitted from one of a plurality of child station apparatuses and including identification information of a transmission source child station apparatus, time information and , and order information assigned to the identification information, to the slave station device that transmitted the timing request information, wherein the order information is determined for each of the plurality of slave station devices. The slave station device that has received the timing setting information sets its own transmission slot on the time axis based on the timing setting information, and each of the plurality of slave station devices Data is transmitted to the master station device directly or via a relay of the slave station device, and the timing setting information includes a relay stage upper limit value determined for the slave station device that received the timing setting information. A slave station apparatus that receives the timing setting information determines the time length of the transmission slot based on the upper limit value of the number of relay stages .

Preferably, the timing setting information includes an upper limit number of transmission retries set for a slave station apparatus that has received the timing setting information , and the slave station apparatus that has received the timing setting information sets the upper limit number of transmission retries. A time length of the transmission slot is determined based on the value . Further, according to the present invention, when a parent station apparatus receives timing request information transmitted from one of a plurality of child station apparatuses and including identification information of a transmission source child station apparatus, time information and , and order information assigned to the identification information, to the slave station device that transmitted the timing request information, wherein the order information is determined for each of the plurality of slave station devices. A slave station apparatus that receives the timing setting information sets its own transmission slot on the time axis based on the timing setting information, and the timing setting information receives the timing setting information. The slave station device that receives the timing setting information including the transmission retry count upper limit value determined for the slave station device determined for the slave station device determines the time length of the transmission slot based on the transmission retry count upper limit value. Characterized by

According to the present invention, data collision can be avoided by simple processing in a system in which data is transmitted from a plurality of slave station devices to a master station device.

It is a figure which shows the structure of a data collection system. 4 is a sequence chart of communication processing executed by a master station device and slave station devices; FIG. 4 is a diagram showing an example of timing setting information; 4 is a timing chart of processing for a slave station device to transmit sensor data; 4 is a timing chart of processing for a slave station device to transmit sensor data; FIG. 10 is a diagram showing an example of timing setting information when a relay route is constructed; 4 is a timing chart of processing for a slave station device to transmit sensor data; 3 is a diagram illustrating an example of hardware configuration of a slave station device; FIG. It is a figure which shows the structural example of the hardware of a master station apparatus.

An embodiment of the present invention will be described with reference to each drawing. The same items shown in a plurality of drawings are denoted by the same reference numerals, and descriptions thereof are omitted.

FIG. 1 shows the configuration of a data collection system 100 according to an embodiment of the invention. A data collection system 100 includes a master station device 10 and a plurality of slave station devices 12-1 to 12-N. Each of the plurality of slave station devices 12-1 to 12-N (hereinafter sometimes referred to as slave station device 12) has a sensor . The sensor 14 may be a temperature sensor, humidity sensor, illumination sensor, vibration sensor, water level sensor, or the like. Each slave station device 12 acquires a detected value from the sensor 14 and wirelessly transmits data (sensor data) including the detected value to the master station device 10 . The master station device 10 receives the sensor data transmitted from each slave station device 12 and acquires the detected value of the sensor 14 included in each slave station device 12 .

The slave station devices 12-1 to 12-N are arranged in factories, warehouses, greenhouses for cultivating plants, and the like. When the slave station device 12 is placed in a factory or warehouse, a temperature sensor, a humidity sensor, a vibration sensor, or the like may be used as the sensor 14 . In this case, the master station 10 collects sensor data indicating temperature, humidity, vibration, etc. at the position where each slave station 12 is arranged, and monitors the product. When slave station device 12 is placed in a greenhouse, sensor 14 may be a temperature sensor, a humidity sensor, an illuminance sensor, or the like. In this case, the master station 10 collects sensor data indicating the temperature, humidity, illuminance, etc. at the position where each slave station 12 is arranged, and monitors the environment of the crops. Each child station device 12 is equipped with a battery, and operates with power output from the battery.

The master station device 10 has a reference clock that counts the reference time in the data collection system 100 . The slave station device 12 has a local clock for defining the timing of the processing that it executes. The master station device 10 and each slave station device 12 execute synchronization processing, which will be described later, to synchronize the count value of the reference clock and the count value of the local clock. The count values of the reference clock and the local clock are time information based on the time when counting of time is started. Each slave station device 12 recognizes a transmission slot assigned to itself among a plurality of transmission slots set in the data collection system 100 according to its own local clock, and transmits sensor data to the master station during the time period of the transmission slot. Send to device 10 .

A transmission cycle T0 for transmitting sensor data is predetermined for the slave station devices 12-1 to 12-N. After transmitting the sensor data in the time period of the first transmission slot assigned to itself, each slave station device 12 transmits the sensor data every time the transmission cycle T0 elapses according to the count value of its own local clock. .

FIG. 2 conceptually shows a sequence chart of communication processing executed by the master station device 10 and each slave station device 12 . Here, to simplify the explanation, processing executed between the master station device 10 and two slave station devices 12-1 and 12-2 is shown. A straight line extending downward from each of the notations of the master station device 10 and slave station devices 12-1 and 12-2 is the time axis. Communication processing includes synchronization processing and data collection processing, and synchronization processing is executed prior to data collection processing.

Synchronization processing will be described. A slave station ID (IDentification) is stored in the master station device 10 as identification information for identifying each slave station device 12 . The master station device 10 further stores a transmission sequence number corresponding to each slave station ID. The transmission order number indicates the order in which the transmission slots assigned to each child station device 12 are arranged on the time axis, and is order information that indicates the order in which each child station device 12 transmits sensor data. The transmission order number may be determined according to the order in which the slave station IDs of the slave station devices 12 are stored. A code such as an alphabet indicating the transmission order of each slave station device 12 may be used instead of the transmission order number.

Further, in the master station device 10, a transmission retry count upper limit value is stored as communication restriction information commonly set for each slave station device 12. FIG. The transmission retry count upper limit value is a numerical value indicating the number of retransmissions of sensor data allowed when the slave station device 12 fails to transmit the sensor data to the master station device 10 and then transmits the sensor data again. say. By setting an upper limit on the number of transmission retries and restricting communication, it is possible to avoid delays in processing of other slave station devices 12 due to failure of one slave station device 12 to transmit sensor data. A determination as to whether the process of transmitting the sensor data from the slave station device 12 to the master station device 10 has succeeded or failed may be made based on whether or not the slave station device 12 has received the acknowledge information. The acknowledge information is transmitted from the master station device 10 to the slave station device 12 when the master station device 10 receives the sensor data.

The slave station device 12-1 transmits timing request information including its own slave station ID as source identification information to the master station device 10 (T1). The master station device 10 receives the timing request information and extracts the slave station ID from the timing request information. The master station device 10 transmits to the slave station device 12-1 timing setting information including the count value (reference count value) of the reference clock, the transmission retry count upper limit value, and the transmission sequence number associated with the slave station ID. (R1). The slave station device 12-1 extracts the reference count value, the transmission retry count upper limit value, and its own transmission order number from the timing setting information.

FIG. 3 conceptually shows an example of the timing setting information. The timing setting information includes a command, a reference count value, an upper limit value for the number of transmission retries, and a child station ID whose transmission sequence number is 1 to N. The command includes information for distinguishing the timing setting information from other information, the slave station ID of the transmission source, the ID of the master station device 10 of the destination, etc., and the timing setting information is transmitted from the slave station device 12 to the master station device 10. contains the information necessary to

As shown in FIG. 2, processing similar to that executed between slave station device 12-1 and master station device 10 is also performed between slave station device 12-2 and master station device 10. executed. The slave station device 12-2 transmits the timing request information to the master station device 10 (T2), and the master station device 10 that received the timing request information transmits timing setting information to the slave station device 12-2 (R2). The slave station device 12-2 extracts the reference count value, transmission retry count upper limit value, and transmission order number from the timing setting information.

In the synchronization process, the slave station device 12-j (j is 1 or 2) adjusts the count value of its own local clock to the reference count value. Further, the slave station device 12-j determines the time length of the transmission slot based on the transmission retry count upper limit value. The time length of the transmission slot is determined to be a larger value as the upper limit of the number of transmission retries is larger. Further, the slave station device 12-j sets its own transmission slot on the time axis based on the transmission order number. For example, the time when the transmission cycle T0 has passed from the time corresponding to the reference count value is defined as the reference time t0, the time length of the transmission slot is TS, and the transmission sequence number is M. Find the transmission slot time zone for .

Start time of transmission slot time zone ts = t0 + (M-1) TS
End time of transmission slot time period te=t0+M·TS

Through such processing, the slave station device 12-j sets a transmission slot for transmitting sensor data next. A transmission order number M indicates a transmission order determined for one slave station device 12 and another slave station device 12 different from that slave station device 12 . Therefore, the transmission slots are set in the order according to the transmission order number for the child station device 12-j.

The slave station device 12-j transmits sensor data to the master station device 10 when the count value of its own local clock reaches a value corresponding to its own transmission slot time period. The slave station device 12-j transmits the sensor data at a predetermined transmission cycle T0 using the first set transmission slot as a reference for transmission timing. That is, after transmitting the sensor data in the initially set transmission slot time zone, the slave station device 12-j repeatedly transmits the sensor data at the transmission cycle T0 according to the count value of its own local clock.

The lower part of FIG. 2 conceptually shows frames FR1 and FR2 composed of transmission slots S1 to SN set by the slave station devices 12-1 to 12-N. Frames FR1 and FR2 are arranged on the time axis with a transmission period T0. After the frame FR2, similar frames are continued at time intervals of the transmission period T0. The transmission slots S1 to SN included in the frame FR1 are set by the master station device 10 and the slave station devices 12-1 to 12-N performing synchronization processing. On the other hand, each of the slave station devices 12-1 to 12-N recognizes the frames after the frame FR2 independently of the processing of the master station device 10 according to the count value of the local clock.

In each frame, among the transmission slots S1 to SN set by the slave station devices 12-1 to 12-N, the transmission slot Sp set by the slave station device 12-1 and the transmission slot Sp set by the slave station device 12-2 are included. It contains the transmission slots Sq that have been specified. p is any integer from 1 to N, and q is any integer from 1 to N different from p. The slave station device 12-1 transmits sensor data to the master station device 10 in the transmission slot Sp, and the slave station device 12-2 transmits sensor data to the master station device 10 in the transmission slot Sq. The master station device 10 receives the sensor data transmitted from each slave station device 12 and acquires the detection value by the sensor 14 from each sensor data.

Here, an embodiment in which two slave station devices 12-1 and 12-2 execute synchronization processing with the master station device 10 and transmit sensor data to the master station device 10 is shown. Even when there are three or more slave station devices 12, each slave station device 12 executes the same synchronization processing as slave station devices 12-1 and 12-2 and transmits sensor data.

FIG. 4 conceptually shows a timing chart of processing for transmitting sensor data by the slave station devices 12-1 to 12-N. However, in this example, transmission order numbers 1 to N are associated with the slave station devices 12-1 to 12-N, respectively. The child station devices 12-1 to 12-N transmit the sensor data to the master station device 10 in the time period of the transmission slots S1 to SN included in the frame FR1 set by the synchronization process. From frame FR2 onward, each slave station device 12 transmits sensor data in the transmission period T0 according to the count value of its own local clock, so that each slave station device 12 transmits sensor data in the time zone of each transmission slot. do.

Synchronization processing may be performed at predetermined time intervals. For example, synchronization processing may be performed every 6 to 12 hours. In this case, the slave station device 12 may transmit the timing request information and receive the timing setting information in the transmission slot assigned to itself. Further, the slave station device 12 may transmit the timing request information and receive the timing setting information in the time period between adjacent frames.

Each slave station device 12 may be in a sleep state after completing the transmission of the sensor data until the next transmission of the sensor data. Here, the sleep state refers to a state in which the power supply to some of the constituent elements of the slave station device 12 is cut off. Some of the components referred to here are not necessary for the startup operation when transmitting sensor data next time. For example, a local clock and an electronic circuit for recognizing the count value of the local clock are components necessary for activation operation when transmitting sensor data next time, and are excluded from components whose power supply is cut off.

FIG. 5 shows a timing chart when the slave station device 12 transmits sensor data in the transmission slot time zones set in each of the frames FR1, FR2, FR3, . It is In the time zone ACT during which the slave station device 12 transmits sensor data, power is supplied to the constituent elements necessary for sensor data transmission, and the slave station device 12 is in an active state. During the time period SLP from the completion of sensor data transmission to the next sensor data transmission, slave station device 12 is in a sleep state. Since the slave station device 12 is in the sleep state, power consumption is reduced, and the frequency of battery charging or battery replacement becomes low.

According to such a data collection system 100, it is avoided that a plurality of slave station devices 12 transmit sensor data in overlapping time zones. After the synchronization processing is executed, each child station device 12 recognizes the sensor data transmission time zone independently of the processing of the master station device 10 . As such, the processing performed by the entire data collection system 100 is simplified. Synchronization processing is started when slave station device 12 transmits timing request information. Therefore, it becomes possible to periodically execute the synchronization process according to the timing recognized by each slave station device 12, and it becomes easy to periodically execute the synchronization process.

Furthermore, the time length of the transmission slot is set to a larger value as the transmission retry count upper limit value increases. Therefore, under the condition that the slave station device 12 retransmits the sensor data a number of times equal to or less than the transmission retry count upper limit, multiple slave station devices 12 are prevented from transmitting sensor data in overlapping time slots.

An embodiment in which each slave station device 12 directly transmits sensor data to the master station device 10 has been described above. Each child station device 12 may transmit sensor data to the master station device 10 via relay transmission of one or more other child station devices 12 . In this case, in the data collection system 100, the upper limit of the number of relay stages is determined as the communication restriction information, and the relay route is constructed so as not to exceed the upper limit of the number of relay stages. For example, if the relay stage upper limit value is K, when a slave station device 12 transmits sensor data to the master station device 10, other slave station devices 12 are allowed to relay transmission up to K times.

FIG. 6 shows timing setting information when a relay route is constructed. A relay stage number upper limit value is added to the timing setting information shown in FIG. When setting its own transmission slot, the slave station device 12 determines the time length of the transmission slot based on not only the upper limit of the number of transmission retries but also the upper limit of the number of relay stages. The time length of the transmission slot is determined to be a larger value as the upper limit of the number of transmission retries is larger, and to a larger value as the upper limit of the number of hops is larger.

FIG. 7 conceptually shows a timing chart of processing for transmitting sensor data by the slave station devices 12-1 to 12-N. In this example, slave station device 12-3 transmits sensor data to master station device 10 via relay transmission of slave station device 12-1. Further, slave station device 12-N transmits sensor data to master station device 10 via relay transmission of slave station devices 12-3 and 12-1. The time length of the transmission slot is determined to be a larger value as the upper limit value of the number of hops is larger. Therefore, even when a certain slave station device 12 transmits sensor data to the master station device 10 via relay transmission of another slave station device 12, a plurality of slave station devices 12 overlap the time zone. Sending sensor data is avoided.

When a relay path is constructed in the data collection system 100, the slave station device 12 that performs relay transmission relays the sensor data transmitted from the other slave station devices 12 in addition to the time period during which the slave station device 12 itself transmits the sensor data. It will also be in active state during the time period. The slave station device 12 may be in a sleep state during a time period that is not an active state time period. Further, each slave station device 12 may be in the active state during the frame time period for the slave station devices 12-1 to 12-N, and may be in the sleep state during other time periods. The child station device 12 is in an active state during a time period during which it transmits sensor data, is in a relay state during a time period during which it relays sensor data transmitted from another slave station device 12, and is in a sleep state during other time periods. may be Here, the relay state is a state in which power is supplied only to components required for relay transmission. These states are switched at timing according to the count value of the local clock.

FIG. 8 shows a hardware configuration example of the slave station device 12 . The slave station device 12 includes a slave station control section 20 , a slave station radio section 22 , a sensor 14 , a local clock 24 , a storage section 26 , a battery 30 and a power supply circuit 32 . The sensor 14 may be a temperature sensor, humidity sensor, illumination sensor, vibration sensor, water level sensor, or the like. The sensor 14 outputs the detected value to the slave station control section 20 .

The slave station control unit 20 may be a processor that executes a program stored in advance by itself or a program stored in the storage unit 26 . The slave station control unit 20 may temporarily store data obtained in the course of arithmetic processing in the storage unit 26 . The child station control unit 20 and the child station radio unit 22 execute the synchronization processing and data collection processing described above. In the synchronization process, the slave station control section 20 outputs timing request information to the slave station radio section 22, and the slave station radio section 22 transmits the timing request information. Further, the child station radio section 22 receives the timing setting information and outputs it to the child station control section 20 .

In the data collection process, the slave station control unit 20 outputs sensor data to the slave station radio unit 22, and the slave station radio unit 22 transmits the sensor data. The local clock 24 counts the time and outputs the count value to the slave station controller 20 . In synchronization processing and data collection processing, slave station control section 20 uses the count value output from local clock 24 . The storage unit 26 may store routing information and the like necessary for communication with the master station device 10 .

The battery 30 may be a disposable primary battery or a secondary battery that can be repeatedly charged and discharged. When the slave station device 12 is in the active state, the power supply circuit 32 supplies power supplied from the battery 30 to the slave station control section 20 , the slave station radio section 22 , the local clock 24 and the storage section 26 . If the sensor 14 requires mains power, the power supply circuit 32 also supplies the mains power to the sensor 14 . When the slave station device 12 is in the sleep state, the power supply circuit 32 cuts off the power supplied to some components.

FIG. 9 shows a hardware configuration example of the master station device 10 . The master station device 10 includes a master station control unit 40 , a master station radio unit 42 , a reference clock 44 and a storage unit 46 . The master station control unit 40 may be a processor that executes a program stored in advance in itself or a program stored in the storage unit 46 . The master station control unit 40 may temporarily store data obtained during the arithmetic processing in the storage unit 46 . The master station control unit 40 and the master station radio unit 42 execute the synchronization processing and data collection processing described above. In the synchronization process, the master station radio section 42 receives the timing request information and outputs it to the master station control section 40 . The master station control unit 40 outputs the timing setting information to the master station radio unit 42, and the master station radio unit 42 transmits the timing setting information. In the data collection process, the master station radio section 42 receives sensor data and outputs it to the master station control section 40 .

The reference clock 44 counts time and outputs the count value to the master station control unit 40 . The master station control unit 40 uses the count value output from the reference clock 44 in synchronization processing. Note that the reference clock 44 may be replaced with a clock provided outside the master station device 10 . The storage unit 46 stores routing information necessary for communication with the slave station device 12, communication restriction information such as the upper limit of the number of transmission retries and the upper limit of the number of relay steps, each slave station ID, and each slave station ID. A transmission order number or the like may be stored.

10 master station device, 12, 12-1 to 12-N slave station device, 14 sensor, 20 slave station control section, 22 slave station radio section, 24 local clock, 26, 46 storage section, 40 master station control section, 42 Master station radio unit, 44 reference clock, 100 data acquisition system.

Claims (7)

In the slave station device that transmits data to the master station device,
transmitting timing request information including its own identification information to the master station device;
receiving timing setting information transmitted by the master station device in response to the timing request information;
setting its own transmission slot on the time axis based on the time information and order information included in the timing setting information;
the order information indicates a transmission order determined for the child station device and another child station device different from the child station device;
the slave station device transmits the data at a predetermined transmission cycle using the transmission slot as a reference for transmission timing;
transmitting the data to the master station device directly or via a relay of the other slave station device;
the timing setting information includes a relay stage upper limit value determined for the slave station device;
The slave station device
A slave station apparatus , wherein the time length of the transmission slot is determined based on the upper limit of the number of relay stages . In the slave station device according to claim 1 ,
The timing setting information is
including an upper limit number of transmission retries determined for the slave station device ,
The slave station device
A slave station apparatus, wherein the time length of the transmission slot is determined based on the transmission retry count upper limit value. In the slave station device that transmits data to the master station device,
transmitting timing request information including its own identification information to the master station device;
receiving timing setting information transmitted by the master station device in response to the timing request information;
setting its own transmission slot on the time axis based on the time information and order information included in the timing setting information;
the order information indicates a transmission order determined for the child station device and another child station device different from the child station device;
the slave station device transmits the data at a predetermined transmission cycle using the transmission slot as a reference for transmission timing;
the timing setting information includes an upper limit number of transmission retries determined for the slave station device;
The slave station device
A slave station apparatus, wherein the time length of the transmission slot is determined based on the transmission retry count upper limit value. In the slave station device according to any one of claims 1 to 3 ,
A slave station device, characterized in that it enters a sleep state from the first transmission of said data to the next transmission of said data. A master station device ,
When receiving timing request information transmitted from one of a plurality of slave station devices and including identification information of a slave station device as a transmission source,
transmitting timing setting information including time information and order information assigned to the identification information to the slave station device that transmitted the timing request information;
the order information indicates a transmission order determined for each of the plurality of slave station devices;
A slave station device that receives the timing setting information,
setting its own transmission slot on the time axis based on the timing setting information ;
each of the plurality of slave station devices transmits data to the master station device directly or via a relay of another slave station device;
The timing setting information is
including a relay stage upper limit value determined for a slave station device that has received the timing setting information,
A slave station device that receives the timing setting information,
A master station apparatus , wherein the time length of the transmission slot is determined based on the upper limit value of the number of relay stages . In the master station device according to claim 5 ,
The timing setting information is
including an upper limit number of transmission retries determined for a slave station device that has received the timing setting information ;
A master station apparatus, wherein the slave station apparatus that has received the timing setting information determines the time length of the transmission slot based on the transmission retry count upper limit value . A master station device,
When receiving timing request information transmitted from one of a plurality of slave station devices and including identification information of a slave station device as a transmission source,
transmitting timing setting information including time information and order information assigned to the identification information to the slave station device that transmitted the timing request information;
the order information indicates a transmission order determined for each of the plurality of slave station devices;
A slave station device that receives the timing setting information,
setting its own transmission slot on the time axis based on the timing setting information;
The timing setting information is
including an upper limit number of transmission retries determined for a slave station device that has received the timing setting information;
A slave station device that receives the timing setting information,
A master station apparatus, wherein the time length of the transmission slot is determined based on the transmission retry count upper limit value.

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