WO2023074784A1 - Communication device, communication system, communication method, and program - Google Patents

Abstract

A communication device capable of communicating with another communication device having the same SF value of a spread spectrum scheme is provided. In order to facilitate communication with a plurality of other communication devices having different SF values, the communication device, which is capable of communicating with another communication device having the same SF value of a spread spectrum scheme, communicates with another communication device while switching a plurality of SF values in a time-division manner.

Description

Communication device, communication system, communication method, and program

The present disclosure relates to communication devices, communication systems, communication methods, and programs.

In a radio communication system using the spread spectrum system, in order to communicate between a communication device included in the radio communication system and another communication device, the communication device and the other communication device must have the same SF (Spreading Factor) value. must be set.

Also, there is known a technique of determining the SF value of the spread spectrum method based on, for example, the noise level, the distance from the base station, or the output voltage of the storage element (see Patent Documents 1 to 3, for example).

JP-A-2000-261366 JP 2018-101831 A JP 2019-29771 A

For example, in a communication system in which a communication device such as a gateway communicates with a plurality of other communication devices such as sensors by wireless communication using a spread spectrum method, the other communication devices may be provided with different SFs depending on the installation status of the other communication devices. You have a request to set a value.

However, in the conventional technology, it is difficult for a communication device capable of communicating with other communication devices having the same spread spectrum SF value to communicate with a plurality of other communication devices having different SF values. .

The present disclosure facilitates communication with a plurality of other communication devices with different SF values in a communication device that can communicate with other communication devices with the same spread spectrum SF value.

A communication device according to a first aspect of the present disclosure is a communication device capable of communicating with another communication device having the same SF value in a spread spectrum system, and switching between a plurality of SF values in a time division manner. communicate with

According to the first aspect of the present disclosure, a communication device capable of communicating with other communication devices having the same spread spectrum SF value can easily communicate with a plurality of other communication devices having different SF values. Become.

A second aspect of the present disclosure is the communication device according to the first aspect, wherein the plurality of SF values are arbitrary values within a range of SF values that can be set for the communication device.

A third aspect of the present disclosure is the communication device according to the first or second aspect, wherein the SF value is set in the other communication device by an installer who installs the other communication device. value.

According to a third aspect of the present disclosure, in a communication system in which a communication device such as a gateway communicates with a plurality of other communication devices such as sensors via spread spectrum wireless communication, Different SF values can be set according to the installation situation of the device.

A fourth aspect of the present disclosure is the communication device according to any one of the first to third aspects, wherein the communication device switches the SF value at a switching timing determined for each SF value. connect.

A fifth aspect of the present disclosure is the communication device according to any one of the first to fourth aspects, wherein the communication device changes the SF value at predetermined time intervals to and determines the plurality of SF values based on the communication availability determination result.

A sixth aspect of the present disclosure is the communication device according to the fifth aspect, wherein the communication device performs Modifying the plurality of SF values.

A seventh aspect of the present disclosure is the communication device according to any one of the first to sixth aspects, wherein the communication device can externally set the plurality of SF values.

An eighth aspect of the present disclosure is the communication device according to any one of the first to seventh aspects, wherein the communication device changes the SF value at predetermined time intervals, and A timing for switching the plurality of SF values is determined based on the time when the communication is performed.

A ninth aspect of the present disclosure is the communication device according to the eighth aspect, wherein the communication device changes the timing of switching the plurality of SF values according to radio wave conditions or congestion conditions of the communication. do.

A tenth aspect of the present disclosure is the communication device according to any one of the first to ninth aspects, wherein the communication device can externally set timing for switching the plurality of SF values.

An eleventh aspect of the present disclosure is a communication system including the communication device according to any one of the first to tenth aspects and another communication device, wherein the other communication device communicate with the communication device with the SF value set to .

A twelfth aspect of the present disclosure is the communication system according to the eleventh aspect, wherein the other communication device is a first communication device to which a first SF value is set; and a second communication device configured with a second SF value different from the SF value.

A thirteenth aspect of the present disclosure is the communication system according to the eleventh or twelfth aspect, wherein the other communication device transmits data to the communication device according to a set transmission schedule.

A fourteenth aspect of the present disclosure is the communication system according to any one of the eleventh to thirteenth aspects, wherein the other communication device receives a response from the communication device after transmitting data to the communication device If not, it determines that there is a communication abnormality, holds the data, and retransmits the held data to the communication device when the communication abnormality is resolved.

In a communication method according to a fifteenth aspect of the present disclosure, a communication device capable of communicating with another communication device having the same SF value of the spread spectrum method communicates with the other communication device while switching a plurality of SF values in a time division manner. do.

A program according to a sixteenth aspect of the present disclosure causes a communication device capable of communicating with other communication devices having the same spread spectrum SF value to communicate with the other communication device while switching a plurality of SF values in a time division manner. .

1 is a diagram illustrating an example of a system configuration of a communication system according to one embodiment; FIG. 1 is a diagram (1) for explaining an outline of processing according to an embodiment; FIG. FIG. 2 is a diagram (2) for explaining an outline of processing according to an embodiment; It is a figure which shows the example of the hardware configuration of the communication apparatus which concerns on one Embodiment. It is a figure showing an example of functional composition of a communications system concerning one embodiment. 8 is a flowchart illustrating an example of reception information acquisition processing according to the first embodiment; FIG. 9 is a flowchart showing another example of the reception information acquisition process according to the first embodiment; FIG. 7 is a flowchart showing an example of SF value determination processing according to the first embodiment; 6 is a flowchart showing an example of communication processing of the communication device (master device) according to the first embodiment; 4 is a flowchart showing an example of communication processing of the communication device (child device) according to the first embodiment; FIG. 10 is a flowchart (1) showing an example of reception information acquisition processing according to the second embodiment; FIG. FIG. 10 is a flowchart (2) showing an example of reception information acquisition processing according to the second embodiment; FIG. 9 is a flowchart showing an example of communication processing of a communication device (child device) according to the second embodiment; 10 is a flowchart (1) showing an example of communication processing of the communication device (master device) according to the third embodiment; 14 is a flowchart (2) showing an example of communication processing of the communication device (master device) according to the third embodiment; FIG. 11 is a flow chart showing an example of communication processing of a communication device (child device) according to the third embodiment; FIG. FIG. 16 is a flowchart showing an example of a reception information acquisition process according to the fourth embodiment; FIG. FIG. 14 is a flowchart showing an example of SF value change processing according to the fourth embodiment; FIG. FIG. 14 is a flowchart showing an example of communication processing of a communication device (child device) according to the fourth embodiment; FIG. FIG. 5 is a diagram illustrating an example of changes in SF values in a communication system according to an embodiment;

Each embodiment will be described below with reference to the attached drawings. In the present specification and drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

<System configuration>
FIG. 1 is a diagram illustrating an example of a system configuration of a communication system according to one embodiment. The communication system 1 includes a plurality of communication devices 110a, 110b, 110c, . In the following description, "communication device 110" is used when indicating an arbitrary communication device among the plurality of communication devices 110a, 110b, 110c, . . . Also, the number of communication devices 110 shown in FIG. 1 is an example, and the number may be two or more.

Here, as a specific example, the communication device 100 is a LoRa (registered trademark) (Long Range) Private gateway, and the other communication device 110 is a LoRa Private device (sensor). I do.

LoRa is one of the LPWA (Low Power Wide Area) wireless communications that can achieve wide-area wireless communications with low power consumption, and uses the spread spectrum method for wireless modulation. In LoRa, a trade-off relationship between communication distance and communication speed can be set depending on the magnitude of the setting value (hereinafter referred to as SF value) of the spreading factor (SF) of the spread spectrum system. For example, if the SF value is set larger, the communication speed becomes slower, but the communication distance becomes longer. On the other hand, when the SF value is set smaller, the communication speed becomes faster, but the communication distance becomes shorter. Among LoRa, a public network is called LoRa WAN (Wide Area Network), and a private network is called LoRa Private.

Note that LoRa and LoRa Private are examples of the communication system 1 of the spectrum communication scheme according to the present embodiment. The communication system 1 may be a system to which a spectrum communication method other than LoRa is applied.

In the communication system 1 of the spectrum communication method, for example, when communication is performed between the communication device 100 and the communication device 110a, the same SF value is set to the communication device (base device) 100 and the communication device (child device) 110a. enables communication.

Therefore, in a conventional communication system, for example, when different SF values are set in a plurality of communication devices 110a, 110b, 110c, . Installed. However, with this method, for example, when the number of communication devices 110 having different SF values increases, a wireless module is added to the communication device 100, which requires expansion of the mounting space. It is also conceivable to install wireless modules corresponding to all settable SF values in the communication apparatus 100 from the beginning, but there is a problem that the cost increases.

As described above, according to the conventional technique, the communication device 100 capable of communicating with another communication device 110 having the same SF value of the spread spectrum system communicates with a plurality of other communication devices 110a, 110b, 110c, . . . having different SF values. It was difficult to communicate with

Therefore, the communication device 100 according to the present embodiment communicates with a plurality of other communication devices 110a, 110b, 110c, . As a result, the communication device 100 can communicate with a plurality of other communication devices 110a, 110b, 110c, . can.

<Overview of processing>
2 and 3 are diagrams for explaining an outline of processing according to an embodiment. In FIG. 2, communication devices 110a, 110b, and 110c have SF values of “5,” “8,” and SF values determined by an installer (or an administrator who manages each communication device) who installs each communication device, for example. Assume that it is set to "12". Further, it is assumed that the communication devices 110a, 110b, and 110c each transmit data (for example, sensor data, etc.) at predetermined transmission timings. Note that the communication device 100a is an example of a first communication device, and the SF value "5" is an example of a first SF value. Also, the communication device 100b is an example of a second communication device, and the SF value "8" is an example of a second SF value.

(Acquisition processing of received information)
The communication device 100 receives data (for example, sensor data, etc.) transmitted by another communication device 110 while switching the SF value at predetermined time intervals. For example, as in state A in FIG. Signal Strength Indicator) and information such as transmission intervals are stored in the reception information 210a.

Further, for example, as in state B in FIG. 2, during a period in which the SF value of the communication device 100 is "8", the communication device 100 receives data transmitted by the communication device 110b, and , and transmission intervals are stored in the reception information 210b. Similarly, for example, as in state C of FIG. Information such as RSSI and transmission interval is stored in the reception information 210c.

(Determination process of SF value)
Further, the communication device 100 determines a plurality of SF values to be switched by the communication device 100 in a time division manner, switching timing of the SF values, and the like, based on the acquired reception information 210a to 210c.

For example, as shown in FIG. 3, the communication device 100 inputs the acquired received information (for example, received information 210a to 210c) to the SF value determination model 301 that has been learned by machine learning, thereby obtaining a plurality of SF values. , and the switching timing of the SF value. In this case, for example, using an information processing device or the like, the SF value determination model 301 is generated in advance using a plurality of learning data with a plurality of received information as explanatory variables and an optimal SF value as an objective variable (teaching data). keep learning.

The communication device 100 communicates with the communication devices 110a to 110c while switching the plurality of SF values in a time division manner according to the determined combination of the plurality of SF values and the switching timing 302. Here, time division means that communication is performed while switching a plurality of SF values temporally using one wireless module, and is called time slicing or time sharing, for example.

In the example of FIG. 3, the communication device 100 sets the SF value to "5" in a period T5 from time t0 to t1, and sets the SF value to "8" in a period T8 from time t1 to t2. , during a period T12 from time t2 to time t3, communication is performed with the SF value set to "12".

The combination of the multiple SF values "5", "8", and "12" to be set is mainly determined by the "SF value" etc. included in the received information 210a to 210c. Also, the periods "T5", "T8", and "T12" are mainly determined by the "reception time" and the "transmission interval" included in the reception information 210a to 210c. Therefore, when the number of communication devices 110 is small and the transmission timings do not overlap, the communication device 100 determines the plurality of SFs based on the received information 210a to 210c without depending on the SF value determination model 301. A combination of values and switching timing 302 may be determined.

Note that the communication devices 110a, 110b, and 110c may be controlled so that the transmission time, the transmission interval, or the like differs depending on the set SF value.

Thus, according to the present embodiment, the communication device 100 can communicate with a plurality of other communication devices 110a, 110b, 110c, . can be done. Therefore, according to the present embodiment, the communication device 100 can be used with a plurality of other communication devices 110a, 110b, 110c, . can communicate with

As described above, according to the present embodiment, the communication device 100 capable of communicating with other communication devices having the same spread spectrum SF value can easily communicate with a plurality of other communication devices 110 having different SF values. Become.

In the above description, the communication device 100 is a parent device such as a gateway, and the other communication devices 110a, 110b, 110c, . . . are child devices such as sensors. Not limited. For example, the communication device 100 is a child device such as a sensor that transmits sensor data to a plurality of gateways, etc., and the other communication devices 110a, 110b, 110c, . It may be a parent device such as In this case, the communication device 100, which is a child device such as a sensor, uses one wireless module to transmit data to other communication devices 110a, 110b, 110c, etc., which are parent devices such as gateways having different SF values. be able to send.

<Hardware configuration>
The communication device (parent device) 100 and the communication device (child device) 110 according to this embodiment have, for example, a hardware configuration as shown in FIG.

FIG. 4 is a diagram showing an example of the hardware configuration of a communication device according to one embodiment. The communication device 100 and the communication device 110 have, for example, a processor 401, a memory 402, a storage device 403, a wireless module 404, an output device 405, an input device 406, a bus 407, and the like.

The processor 401 is, for example, a computing device such as a CPU (Central Processing Unit) that implements various functions by executing a predetermined program stored in a storage medium such as the storage device 403 or memory 402. The memory 402 includes, for example, RAM (Random Access Memory), which is a volatile memory used as a work area of the processor 401, etc., and ROM (Read Only Memory), which is a non-volatile memory that stores a program for starting the processor 401. Memory), etc. The storage device 403 is a large-capacity storage device that stores an OS (Operating System), programs such as applications, and various data and information. etc.

The wireless module 404 includes a wireless circuit, a baseband circuit, a communication control circuit, and the like for communicating with other communication devices using spread spectrum wireless communication such as LoRa. The output device 405 is, for example, an output device that outputs to the outside, such as a display, a speaker, and an LED (Light Emitting Diode). The input device 406 is, for example, an input device that accepts input from the outside, such as a touch panel, keyboard, or pointing device. A bus 407 is connected to each component described above, and transmits, for example, address signals, data signals, and various control signals.

<Functional configuration>
FIG. 5 is a diagram illustrating an example of a functional configuration of a communication system according to one embodiment;

(Functional configuration of communication device 100)
The communication device (master device) 100 has, for example, a control unit 500, a communication unit 501, a storage unit 502, and the like.

The control unit 500 is implemented by, for example, the processor 401 of FIG. It implements the change unit 506 and the like.

The acquisition unit 503 receives data transmitted by the other communication devices 110a, 110b, and 110c while switching the SF value of the communication device 100 at predetermined time intervals, and obtains data such as reception time, SF value, RSSI, and transmission interval. Acquire reception information Execute reception information acquisition processing. For example, the acquisition unit 503 acquires the reception information 210a, 210b, 210c, etc. described in FIG.

Based on the received information acquired by the acquisition unit 503, the determination unit 504 executes SF value determination processing for determining a plurality of SF values to be switched by the communication apparatus 100 in a time division manner, the switching timing of the SF values, and the like. For example, as described with reference to FIG. 3, the determination unit 504 inputs the received information acquired by the acquisition unit 503 to the trained SF value determination model 301, thereby obtaining a plurality of SF values and switching timings of the SF values. 302 is determined.

The switching unit 505 executes switching processing for switching the SF value of the communication unit 501 according to the combination of multiple SF values determined by the determination unit 504 and the switching timing 302 . For example, the switching unit 505 sets the SF value “5” at time t0 to the communication unit 501 according to the combination of a plurality of SF values and the switching timing 302 as shown in FIG. A value of "8" is set, and an SF value of "12" is set at time t2. Note that the switching unit 505 is not limited to the example of FIG. 3, and may set an arbitrary value within the range of SF values that can be set in the communication apparatus 100 and switch.

The changing unit 506 changes the SF value of the other communication device 100 based on, for example, the state of radio communication congestion or the distance to the other communication devices 110a, 110b, 110c, etc. Execute the process. Note that the change unit 506 is optional and not essential.

Note that the functional configuration of the control unit 500 shown in FIG. 5 is an example. In addition to the above processes, the control unit 500 also executes general communication control processes such as setting up radio channels, transmitting and receiving data, or controlling the communication device 110 .

The communication unit 501 is implemented by, for example, the wireless module 404 shown in FIG. , and execute communication processing to communicate with. For example, the communication unit 501 receives data transmitted by the communication devices 110a, 110b, 110c, .

The storage unit 502 is implemented by, for example, the storage device 403 or memory 402 in FIG. 4, and stores the SF value determination model 301 and the like described in FIG. For example, a manufacturer who manufactures the communication device 100 or an administrator who manages the communication device 100 previously stores the learned SF value determination model 301 in the storage unit 502 using an information processing device or the like.

(Functional configuration of communication device 110)
The communication device (child device) 110 has, for example, a control unit 510, a communication unit 501, a storage unit 502, and the like.

The control unit 510 is implemented by, for example, the processor 401 in FIG. 4, and executes a program stored in a storage medium such as the storage device 403 or the memory 402 to implement the setting unit 514, the reception unit 513, and the like. there is In FIG. 5, the communication devices 110b and 110c are assumed to have the same functional configuration as the communication device 110a.

The reception unit 513 executes reception processing for receiving settings of SF values or transmission schedule settings from the outside. For example, the reception unit 513 may use the input device 406 in FIG. may accept the setting.

The setting unit 514 executes setting processing for setting the SF value received by the receiving unit 513, the transmission schedule, and the like in the communication unit 511. Note that the functional configuration of the control unit 510 shown in FIG. 5 is an example. In addition to the reception processing and setting processing described above, the control unit 510 also executes general communication control processing such as wireless channel setting and data transmission/reception.

The communication unit 511 is realized by, for example, the wireless module 404 shown in FIG. do. For example, the communication unit 501 transmits data (eg, sensor data, etc.) to the communication device 100 according to the SF value and transmission schedule set by the control unit 510 .

Preferably, the communication unit 511 (or the control unit 510) determines that there is a communication abnormality and retains the data when there is no response from the communication device 100 after data is transmitted to the communication device 100, and when the communication abnormality is resolved. Then, the held data is retransmitted to the communication device 100 .

The storage unit 512 is implemented by, for example, the storage device 403 or memory 402 in FIG.

Note that the functional configuration of the communication system 1 shown in FIG. 5 is an example. For example, the control unit 500 of the communication device 100 may further include a reception unit 513, a setting unit 514, or the like. Also, the control unit 510 of the communication device 110 may further include an acquisition unit 503, a determination unit 504, a switching unit 505, or the like.

<Process flow>
Next, the processing flow of the communication method according to this embodiment will be described.

[First Embodiment]
(Received information acquisition process 1)
FIG. 6 is a flowchart illustrating an example of reception information acquisition processing according to the first embodiment. This processing shows an example of the reception information acquisition processing executed by the communication device 100 described with reference to FIG. Here, an example of processing when the SF value that can be set in the other communication devices 110a, 110b, and 110c is any one of "5", "8", and "12" will be described.

In step S601, the acquisition unit 503 of the communication device 100 sets the SF value "5" to the communication unit 501, receives data for a predetermined time, and acquires reception information. For example, the acquisition unit 503 acquires the reception information 210a including the reception time, SF value, RSSI (reception level), transmission interval, etc. of the received data, as described with reference to FIG.

In step S602, the acquisition unit 503 sets the SF value "8" to the communication unit 501, receives data for a predetermined time, and acquires reception information. For example, the acquisition unit 503 acquires the reception information 210b including the reception time, SF value, RSSI, transmission interval, etc. of the received data, as described with reference to FIG.

In step S603, the acquisition unit 503 sets the SF value "12" in the communication unit 501, receives data for a predetermined period of time, and acquires reception information. For example, the acquisition unit 503 acquires the reception information 210c including the reception time, SF value, RSSI, transmission interval, etc. of the received data, as described with reference to FIG.

In step S604, the acquisition unit 503 determines whether or not the required amount of received information has been reached. For example, the acquisition unit 503 determines whether or not the acquired reception information includes necessary data such as reception time, SF value, RSSI (reception level), transmission interval, and the like. If the required amount of received information has not been reached, the acquisition unit 503 returns the process to step S601. On the other hand, if the required amount of received information has been reached, the acquisition unit 503 causes the process to proceed to step S605.

After moving to step S605, the acquisition unit 503 notifies the determination unit 504 of the acquired reception information (reception information 210a to 210c). By the processing in FIG. 6, the acquisition unit 503 can acquire the reception information used for the SF value determination processing.

(Received information acquisition process 2)
FIG. 7 is a flowchart illustrating another example of the reception information acquisition process according to the first embodiment. Here, an example of processing when the SF values set in the other communication devices 110a, 110b, and 110c can be set to any value between 1 and N (N is an integer equal to or greater than 2) will be described. do.

In step S701, the acquisition unit 503 of the communication device 100 initializes the variable i to 1, and executes the processing from step S702.

After moving to step S702, the acquisition unit 503 sets the SF value "i" in the communication unit 501 and receives predetermined time data. Preferably, the predetermined time is set to be sufficiently long, for example, so that data transmitted by the other communication device 110 can be received multiple times.

In step S703, the acquisition unit 503 determines whether the communication unit 501 has received data. When data is received, the acquisition unit 503 causes the process to proceed to step S704. On the other hand, if data has not been received, the acquisition unit 503 shifts the process to step S705.

After moving to step S704, the acquisition unit 503 acquires the reception information when the SF value is "i".

After moving to step S705, the acquisition unit 503 determines whether the value of i has reached the maximum value N of the SF value. If the value of i has not reached the maximum SF value N, the acquisition unit 503 causes the process to proceed to step S706. On the other hand, when the value of i reaches the maximum value N of the SF values, the acquisition unit 503 shifts the processing to step S707.

After moving to step S706, the acquisition unit 503 adds "1" to i and returns the process to step S702. On the other hand, after proceeding to step S707, the acquisition unit 503 notifies the determination unit 504 of the acquired reception information.

7, the acquisition unit 503 changes the SF value at predetermined time intervals to determine whether or not communication with the other communication device 110 is possible. Received information can be obtained to determine the value.

(Determination process of SF value)
FIG. 8 is a flowchart illustrating an example of SF value determination processing according to the first embodiment. This process represents an example of the SF value determination process executed by the determination unit 504 of the communication apparatus 100 . It is assumed that the communication device 100 has already executed the received information acquisition process described with reference to FIG. 6 or 7 at the start of the process shown in FIG.

In step S801, the determination unit 504 of the communication device 100 inputs the received information (for example, received information 210a to 210c) acquired by the acquisition unit 503 to the learned SF value determination model 301 stored in the storage unit 502.

In step S<b>802 , the determination unit 504 applies to the communication apparatus 100 the combination of multiple SF values and the switching timing output by the learned SF value determination model 301 . For example, the determining unit 504 determines the time T5 when the SF value is “5”, the time T8 when the SF value is “8”, and the SF A time "T12" or the like with a value of "12" is determined and stored in the storage unit 502 or the like.

By the processing in FIG. 8, the determination unit 504 can determine the combination of multiple SF values and the switching timing 302 as shown in FIG. 3, for example, based on the acquired reception information.

(Communication processing of communication device 100)
FIG. 9 is a diagram illustrating an example of communication processing of the communication device (master device) according to the first embodiment. This processing is an example of processing in which the communication device 100 receives data from other communication devices 110a, 110b, 110c, etc., based on the combination of a plurality of SF values and the switching timing 302 determined by the determination unit 504. showing.

In step S<b>901 , the switching unit 505 of the communication device 100 sets the SF value “n” to the communication unit 501 based on the combination of multiple SF values and the switching timing 302 determined by the determining unit 504 . For example, in the case of a combination of multiple SF values and switching timing 302 as shown in FIG.

In step S902, the communication unit 501 receives data of SF value n for time Tn. For example, when the value of n is "5" at the combination of a plurality of SF values and the switching timing 302 as shown in FIG. receive. Also, when the value of n is "8", the communication unit 501 receives data with an SF value of "8" during time T8. Similarly, when the value of n is "12", the communication unit 501 receives data with an SF value of "12" during time T12.

In steps S903 and S904, the communication unit 501 (or the control unit 500) confirms the content of the received data and determines whether or not it is a new reception format. If it is a new reception format, the communication unit 501 shifts the process to step S905. On the other hand, if it is not a new reception format, the communication unit 501 shifts the process to step S907.

After moving to step S905, the communication unit 501 starts receiving new data. Also, in step S906, the communication unit 501 (or the control unit 500) holds the reception format.

On the other hand, when moving to step S907, the communication unit 501 receives data in the retained reception format.

In step S908, the switching unit 505 updates the SF value "n" in the communication unit 501 based on the combination of multiple SF values and the switching timing 302 determined by the determining unit 504. For example, in a combination of multiple SF values and switching timing 302 as shown in FIG. 3, when the current SF value is "5", the switching unit 505 updates the SF value to "8". Similarly, if the current SF value is "8", the switching unit 505 updates the SF value to "12", and if the current SF value is "12", the switching unit 505 updates the SF value to "5". ”.

By the processing of FIG. 9, the communication device 100 can communicate with other communication devices 110a, 110b, and 110c, for example, while switching a plurality of SF values in a time division manner.

(Communication processing of communication device 110)
FIG. 10 is a diagram illustrating an example of communication processing of the communication device (child device) according to the first embodiment. This processing shows an example of processing in which the communication device (child device) 110 transmits data to the communication device (master device) 100 . It is assumed that setting values such as the SF value and the transmission timing are set in advance in the communication device 110, for example.

In steps S1001 and S1002, the control unit 510 of the communication device 110 waits until the transmission timing, and transmits data using the communication unit 511 when the transmission timing comes.

In step S1003, the control unit 510 determines whether or not an ACK (Acknowledgment) indicating that data has been received has been received from the communication device 100 within a predetermined time. If ACK has not been received, control unit 510 causes the process to proceed to step S1004. On the other hand, when ACK is received, the control unit 510 shifts the process to step S1005.

After moving to step S1004, the control unit 510 holds the transmission data and returns the process to step S1001.

On the other hand, when proceeding to step S1005, the control unit 510 determines whether or not there is unsent data up to the previous time. If there is unsent data, control unit 510 causes the process to proceed to step S1006. On the other hand, if there is no unsent data, control unit 510 returns the process to step S1001.

After moving to step S1006, the control unit 510 uses the communication unit 511 to transmit the held unsent data.

By the process of FIG. 10, the communication device 110 can transmit the unsent data at the next transmission timing and thereafter when the data transmission fails.

As described above, according to the first embodiment, the communication device 100 communicates with a plurality of other communication devices 110a, 110b, 110c, . As a result, the communication device 100 can communicate with a plurality of other communication devices 110a, 110b, 110c, . can.

[Second embodiment]
The communication device 100 has a function of changing a plurality of SF values for communication with other communication devices 110 based on the communication quality of wireless communication or the distance to other communication devices 110a, 110b, 110c, and the like. It's okay to be

(Acquisition processing of received information)
11 and 12 are flowcharts showing an example of reception information acquisition processing according to the second embodiment. This process represents another example of the received information acquisition process executed by the communication device 100 described with reference to FIG. Note that among the processes shown in FIG. 11, the processes of S601 to S605 are the same as the received information acquisition process according to the first embodiment described with reference to FIG. We will focus on points.

If it is determined in step S604 that the required amount of received information has not been reached, then in step S1101 the changing unit 506 of the communication device 100 determines whether or not the communication unit 501 has received the information. For example, if the required amount of received information is not reached at SF value "5" among SF values "5", "8", and "12", the changing unit 506 changes data with SF value "5". Determine whether or not it has been received.

If it has not been received, the changing unit 506 shifts the process to step S1102. On the other hand, if reception is successful, the changing unit 506 shifts the process to step S1201 in FIG.

After moving to step S1102, the changing unit 506 of the communication device 100 transmits an SF value change command to the corresponding other communication device 110 (the communication device 110 that has not received data) so that the communication device 110 to N+1. Here, N is the SF value at which data cannot be received. Further, the changing unit 506 sets the SF value of its own device (communication device 100) to N+1.

Upon moving to step S1103, the acquisition unit 503 of the communication device 100 resets the log of the corresponding other communication device 110 and acquires reception information for a predetermined period of time.

On the other hand, when the process moves from step S1101 to step S1201 in FIG. 12, the changing unit 506 of the communication device 100 calculates the arrival rate, RSSI, or number of retransmissions for a predetermined period with an SF value that does not reach the required amount of received information. etc.

Here, the arrival rate indicates the ratio of data received by the communication device 100 to data transmitted by the other communication devices 110 . Therefore, when the arrival rate is low (below the threshold value), it can be determined that the communication quality is poor (the radio wave condition is poor or the communication is congested). The number of retransmissions indicates the number of times the other communication device 110 has retransmitted the same data. Therefore, when the number of retransmissions is large (when the number of retransmissions is greater than or equal to the threshold), it can be determined that the communication quality is poor. RSSI indicates the reception level (strength) of a received signal, and a larger value indicates a higher reception level. Therefore, if the RSSI value is low (below the threshold), it can be determined that the other communication device 110 is far away.

In step S1202, the changing unit 506 determines, for example, whether the arrival rate is less than the threshold, the RSSI is less than the threshold, and the number of retransmissions is greater than or equal to the threshold. If the above conditions are satisfied, the changing unit 506 determines that the communication quality is poor and the distance from the other communication device 110 is long, and moves the process to step S1203. On the other hand, if the above requirements are not satisfied, the changing unit 506 causes the process to proceed to step S1206.

In step S1203, the changing unit 506 requests the corresponding other communication device (the communication device 110 whose amount of received information has not reached the required amount) to set the SF value to N+1 (transmits a change command). do). where N is the current SF value.

In step S1204, the changing unit 506 determines whether or not an ACK has been received from the corresponding other communication device within a predetermined time. If ACK has not been received, the changing unit 506 returns the process to step S1203. On the other hand, when ACK is received, the changing unit 506 shifts the process to step S1205.

After moving to step S1205, the changing unit 506 sets the SF value of its own device (communication device 100) to N+1, and moves the process to step S1103 in FIG. Through the processing of steps S1202 to S1205, the changing unit 506 increases the SF values of the communication device 100 and the other communication device 110 when the communication quality is poor and the distance to the other communication device 110 is long. Can be changed to a larger value.

On the other hand, when the process moves from step S1202 to step S1206, the changing unit 506 determines, for example, whether the arrival rate is greater than or equal to the threshold, the RSSI is greater than or equal to the threshold, and the number of retransmissions is less than the threshold. If the above conditions are satisfied, the changing unit 506 determines that the communication quality is good and the distance to the other communication device 110 is short, and moves the process to step S1207. On the other hand, if the above requirements are not satisfied, the changing unit 506 returns the process to step S601 in FIG.

In step S1207, the changing unit 506 requests the corresponding other communication device (the communication device 110 whose amount of received information has not reached the required amount) to set the SF value to N−1 (change command ). where N is the current SF value.

In step S1208, the changing unit 506 determines whether or not an ACK has been received from the corresponding other communication device within a predetermined time. If ACK has not been received, the changing unit 506 returns the process to step S1207. On the other hand, when ACK is received, the changing unit 506 shifts the process to step S1209.

After moving to step S1209, the changing unit 506 sets the SF value of its own device (communication device 100) to N-1, and moves the process to step S1103 in FIG. Through the processing in steps S1206 to S1209, changing unit 506 reduces the SF values of communication device 100 and other communication device 110 to smaller values when the communication quality is good and the distance to other communication device 110 is short. can be changed to Note that the processing of steps S1206 to S1209 is optional and not essential.

11 and 12, the communication device 100, for example, based on the radio wave condition, the communication congestion condition, or the distance to the other communication device 110, the SF value for the other communication device 110 can request a change of

(Communication processing of communication device 110)
FIG. 13 is a diagram illustrating an example of communication processing of a communication device (child device) according to the second embodiment. This processing represents another example of processing in which communication device (child device) 110 transmits data to communication device (parent device) 100 . It is assumed that setting values such as the SF value and the transmission timing are set in advance in the communication device 110, for example.

In steps S1301 and S1302, the control unit 510 of the communication device 110 waits until the transmission timing, and transmits data using the communication unit 511 when the transmission timing comes.

In step S<b>1303 , the setting unit 514 of the communication device 110 determines whether or not a command to change the SF value has been received from the communication device 100 . If the SF value change command has not been received, the setting unit 514 returns the process to step S1301. On the other hand, if a command to change the SF value has been received, the setting unit 514 causes the process to proceed to step S1304.

After moving to step S1304, the setting unit 514 sets the requested SF value in the communication unit 511 according to the received SF value change request. Also, in step S1305, the setting unit 514 transmits to the communication apparatus 100 an ACK indicating that the SF value has been changed.

11 to 13, the communication device 100 establishes a plurality of communication devices communicating with the other communication devices 110 based on the communication quality of the wireless communication or the distance to the other communication devices 110a, 110b, 110c, etc. SF values can be changed.

[Third Embodiment]
During communication, the communication device 100 changes a plurality of SF values for communication with other communication devices 110 based on the communication quality of wireless communication or the distance to other communication devices 110a, 110b, 110c, etc. It may have a function to

(Communication processing of communication device 100)
14 and 15 are flowcharts showing an example of communication processing of the communication device (master device) according to the third embodiment. This process represents another example of the communication process executed by the communication device 100 described with reference to FIG. A detailed description of the same processing contents as in the first and second embodiments will be omitted here.

In step S1401, the changing unit 506 of the communication device 100 determines whether the communication unit 501 has received data. If data has not been received, the changing unit 506 causes the process to proceed to step S1402. On the other hand, if data has been received, the changing unit 506 causes the process to proceed to step S1405.

When the process moves to step S1402, 1 is added to the communication disabled counter. Also, in step S1403, the changing unit 506 determines whether or not the value of the communication disabled counter is equal to or greater than the threshold. If the value of the communication disabled counter is greater than or equal to the threshold, the changing unit 506 causes the process to proceed to step S1404. On the other hand, if the value of the communication disabled counter is less than the threshold, the changing unit 506 returns the process to step S1401.

After moving to step S1404, the changing unit 506 adds 1 to the SF value and returns the process to step S1401.

On the other hand, when the process moves from step S1401 to step S1405, the changing unit 506 resets the communication disabled counter. Also, in step S1406, the communication device 100 executes, for example, data reception processing as shown in steps S904 to S907 in FIG. 9, and shifts the processing to step S1501 in FIG.

After moving to step S1501, the changing unit 506 of the communication device 100 acquires the arrival rate, RSSI, number of retransmissions, or the like for a predetermined period.

In step S1502, the changing unit 506 determines, for example, whether the arrival rate is less than the threshold, the RSSI is less than the threshold, and the number of retransmissions is greater than or equal to the threshold. If the above conditions are satisfied, the changing unit 506 causes the process to proceed to step S1503. On the other hand, if the above requirements are not satisfied, the changing unit 506 causes the process to proceed to step S1506.

After moving to step S1503, the changing unit 506 requests the corresponding other communication device to set the SF value to N+1 (transmits a change command). where N is the current SF value.

In step S1504, the changing unit 506 determines whether or not an ACK has been received from the corresponding other communication device within a predetermined time. If ACK has not been received, the changing unit 506 returns the process to step S1503. On the other hand, when ACK is received, the changing unit 506 shifts the process to step S1505.

When the process moves to step S1505, the changing unit 506 sets the SF value of its own device (communication device 100) to N+1. Further, when the transmission timing differs depending on the set SF value, the communication devices 110a, 110b, and 110c change the reception timing according to the changed SF value. After completing the process of step S1505, the changing unit 506 returns the process to step S1401 in FIG.

On the other hand, when the process moves from step S1502 to step S1506, the changing unit 506 determines whether, for example, the arrival rate is greater than or equal to the threshold, the RSSI is greater than or equal to the threshold, and the number of retransmissions is less than the threshold. If the above conditions are satisfied, the changing unit 506 causes the process to proceed to step S1507. On the other hand, if the above requirements are not met, the changing unit 506 returns the process to step S1401 in FIG.

After moving to step S1507, the changing unit 506 requests the corresponding other communication device to set the SF value to N-1 (transmits a change command). where N is the current SF value.

In step S1508, the changing unit 506 determines whether or not an ACK has been received from the corresponding other communication device within a predetermined time. If ACK has not been received, the changing unit 506 returns the process to step S1507. On the other hand, when ACK is received, the changing unit 506 shifts the process to step S1509.

After moving to step S1509, the changing unit 506 sets the SF value of its own device (communication device 100) to N-1. Further, when the transmission timing differs depending on the set SF value, the communication devices 110a, 110b, and 110c change the reception timing according to the changed SF value. After completing the process of step S1509, the changing unit 506 returns the process to step S1401 in FIG.

15, the communication device 100 changes the SF value, the timing for switching the SF value, etc., based on, for example, the radio wave condition, the communication congestion condition, or the distance from the other communication device 110. be able to.

(Communication processing of communication device 110)
FIG. 16 is a flowchart illustrating an example of communication processing of a communication device (child device) according to the third embodiment. This processing shows an example of communication processing of the communication device (child device) 110 corresponding to the communication processing of the communication device (master device) 100 described with reference to FIGS. A detailed description of the same processing contents as in the first and second embodiments will be omitted here.

In steps S1601 and S1602, the control unit 510 of the communication device 110 waits until the transmission timing, and transmits data using the communication unit 511 when the transmission timing comes.

In step S1603, the control unit 510 determines whether or not an ACK indicating that data has been received has been received from the communication device 100 within a predetermined time. If ACK has not been received, control unit 510 causes the process to proceed to step S1604. On the other hand, when ACK is received, control unit 510 causes the process to proceed to step S1609.

After moving to step S1004, the control unit 510 holds the transmission data. Also, in step S1606, control unit 510 adds 1 to the transmission disabled counter.

In step S1607, the control unit 510 determines whether or not the value of the communication disabled counter is equal to or greater than the threshold. If the value of the communication disabled counter is greater than or equal to the threshold, control unit 510 causes the process to proceed to step S1608. On the other hand, if the value of the communication disabled counter is less than the threshold, the changing unit 506 returns the process to step S1601.

After moving to step S1608, the control unit 510 adds 1 to the SF value of its own device (communication device 110).

On the other hand, when the process moves from step S1603 to step S1609, the control unit 510 resets the transmission disable counter.

At step S1610, the control unit 510 determines whether or not there is unsent data up to the previous time. If there is unsent data, control unit 510 causes the process to proceed to step S1611. On the other hand, if there is no unsent data, control unit 510 returns the process to step S1601.

After moving to step S1611, the control unit 510 uses the communication unit 511 to transmit the held unsent data, and returns the process to step S1601.

Also, when the communication device 110 receives the control information from the communication device 100, the processing of steps S1621 and S1622 is executed. In step S1621, when the communication unit 511 of the communication device 110 receives the control information, the control unit 510 executes the process of step S1622.

In step S1622, the control unit 510 determines whether or not the received control information is an SF value change command. If it is an SF value change command, control unit 510 causes the process to proceed to step S1608. On the other hand, if it is not an SF value change command, the control unit 510 returns the process to step S1601, for example. Alternatively, the control unit 510 may execute processing corresponding to the received control information.

14, the communication system 1 changes the SF value and the timing for switching the SF value based on, for example, the radio wave condition, the communication congestion condition, or the distance from the other communication device 110. be able to.

[Fourth embodiment]
(Acquisition processing of received information)
FIG. 17 is a flowchart illustrating an example of reception information acquisition processing according to the fourth embodiment. This process represents another example of the received information acquisition process executed by the communication device 100 described with reference to FIG. A detailed description of the same processing contents as in the first to third embodiments will be omitted here.

In step S1701, the acquisition unit 503 of the communication device 100 sets the SF value "12" in the communication unit 501.

In step S1702, the communication unit 501 receives predetermined time data with the set SF value.

In step S1703, the acquisition unit 503 determines whether the communication unit 501 has received the data. If the data can be received, the acquisition unit 503 causes the process to proceed to step S1704. On the other hand, if the data cannot be received, the acquisition unit 503 shifts the process to step S1706.

After moving to step S1704, the acquisition unit 503 determines whether or not the received data has reached a predetermined data amount. If the predetermined amount of data has not been reached, the acquisition unit 503 returns the process to step S1702. On the other hand, when the predetermined data amount is reached, the acquisition unit 503 causes the process to proceed to step S1705.

After moving to step S1705, the acquisition unit 503 executes SF value change processing as shown in FIG.

FIG. 18 is a flowchart showing an example of SF value change processing according to the fourth embodiment. In step S1801, the changing unit 506 of the communication device 100 acquires the arrival rate, RSSI, number of retransmissions, or the like for a predetermined period.

In step S1802, the changing unit 506 determines whether, for example, the arrival rate is greater than or equal to the threshold, the RSSI is greater than or equal to the threshold, and the number of retransmissions is less than the threshold. If the above conditions are not satisfied, the changing unit 506 causes the process to proceed to step S1803. On the other hand, if the above condition is satisfied, the changing unit 506 causes the process to proceed to step S1806.

After moving to step S1803, the changing unit 506 requests the corresponding other communication device to set the SF value to N+1 (transmits a change command). where N is the current SF value.

In step S1804, the changing unit 506 determines whether or not an ACK has been received from the corresponding other communication device within a predetermined time. If ACK has not been received, the changing unit 506 returns the process to step S1803. On the other hand, when ACK is received, the changing unit 506 shifts the process to step S1805.

After moving to step S1805, the changing unit 506 sets the SF value of its own device (communication device 100) to N+1. However, if the current SF value is 12, the changing unit 506 keeps the SF value at 12.

On the other hand, when the process moves from step S1802 to step S1806, the change unit 506 requests the corresponding other communication device to set the SF value to N-1 (transmits a change command). where N is the current SF value.

In step S1807, the changing unit 506 determines whether or not an ACK has been received from the corresponding other communication device within a predetermined time. If ACK has not been received, the changing unit 506 returns the process to step S1806. On the other hand, when ACK is received, the changing unit 506 shifts the process to step S1808.

After moving to step S1808, the changing unit 506 sets the SF value of its own device (communication device 100) to N-1, and returns the processing to step S1702 in FIG.

Returning to FIG. 17, the description of the flowchart of the reception information acquisition process will be continued. When the process moves from step S1703 to step S1706 in FIG. 17, the acquisition unit 503 adds 1 to the unsendable counter.

In step S1707, the acquisition unit 503 determines whether or not the value of the communication disabled counter is greater than or equal to the threshold. If the value of the communication disabled counter is not greater than or equal to the threshold, the acquisition unit 503 returns the process to step S1702. On the other hand, if the value of the communication disabled counter is greater than or equal to the threshold, the acquisition unit 503 causes the process to proceed to step S1705.

After moving to step S1708, the acquisition unit 503 adds 1 to the SF value of its own device (communication device 100). However, if the current SF value is "12", the current SF value "12" is maintained.

When the process moves to step S1709, the acquisition unit 503 acquires received information by switching the SF value every predetermined time.

In step S1710, the acquisition unit 503 determines whether or not the required amount of received information has been reached. If the required amount of received information has not been reached, the acquisition unit 503 returns the process to step S1709. On the other hand, if the required amount of received information has been reached, the acquisition unit 503 causes the process to proceed to step S1711.

After moving to step S1711, the acquiring unit 503 notifies the determining unit 504 of the acquired reception information.

(Communication processing of communication device 110)
FIG. 19 is a flowchart illustrating an example of communication processing of a communication device (child device) according to the fourth embodiment. 19, steps S1601 to S1606, S1609 to S1611, and S1621 are the same as the communication processing of the communication device (slave device) according to the third embodiment described with reference to FIG. Now, the description will focus on the differences from the third embodiment.

In step S1901, the control unit 510 of the communication device 110 determines whether or not the value of the communication disabled counter is greater than or equal to the threshold. If the value of the communication disabled counter is greater than or equal to the threshold, control unit 510 causes the process to proceed to step S1902. On the other hand, if the value of the communication disabled counter is less than the threshold, the changing unit 506 returns the process to step S1601.

After moving to step S1902, the control unit 510 adds 1 to the SF value of its own device (communication device 110). However, if the SF value of its own device is "12", control unit 510 maintains the SF value "12".

Also, when control information is received in step S1621, the control unit 510 determines in step S1911 whether or not the received control information is an SF value change command. If the received control information is an SF value change command, control unit 510 causes the process to proceed to step S1912. On the other hand, if the received control information is not an SF value change command, control unit 510 returns the process to step S1601.

After moving to step S1912, the control unit 510 changes the SF value of its own device (communication device 110) according to the SF value change command. However, when the SF value of the device itself is "12", if a change command to add 1 to the SF value is accepted, the control unit 510 does not add the SF value.

As described above, according to the fourth embodiment, the communication system 1 switches between the SF value and the SF value based on, for example, the radio wave condition, the communication congestion condition, or the distance from the other communication device 110. Timing etc. can be changed.

As described above, according to each embodiment of the present disclosure, the communication device 100 that can communicate with other communication devices 110 having the same spread spectrum SF value communicates with a plurality of other communication devices 110 having different SF values. becomes easier.

Further, according to the second to fourth embodiments, the communication system 1 performs communication according to changes in the communication environment such as the radio wave condition, the degree of communication congestion, or the distance to another communication device 110. The SF values of device 100 and communication device 110 can be changed.

(Example of change in SF value)
FIG. 20 is a diagram illustrating an example of changes in SF values in a communication system according to an embodiment. In FIG. 20, the communication device 100 receives data with an SF value of "5" during a period of time t0 to t1, receives data with an SF value of "8" during a period of time t1 to t2, and receives data with an SF value of "8" during a period of time t2 to t3. It is assumed that data is received with an SF value of "11" during the period.

Also, for example, assume that the communication device 100 fails to receive data during the period from time t1 to t2, and the communication disable counter exceeds the threshold. In this case, the communication device 100 changes the SF value from "8" to "9" during the period from time t4 to t5.

On the other hand, the communication apparatus 110b, which has been transmitting data at predetermined time intervals with an SF value of "8", changes its SF value from "8" to "9" when the transmission disable counter exceeds the threshold value at any timing. change to As a result, in the example of FIG. 20, the SF values of both the communication device 100 and the communication device 110 are "9" during the period from time t4 to time t5, and the communication device 100 receives the data transmitted by the communication device 110b. be able to receive.

As another example, during the period from time t5 to time t6, the communication device 100 issues a change instruction to change the SF value from "11" to SF value "12" because the arrival rate of data with the SF value "11" is low. shall be sent.

In this case, when the communication device 110c, which has been transmitting data at predetermined time intervals with an SF value of “11”, receives an instruction to change the SF value to “12” from the communication device 100, for example, the next transmission timing , change the SF value to "12" and transmit the data. This enables the communication device 100 to receive data transmitted by the communication device 110c with an SF value of "12", for example, during the period from time t6 to time t7.

Although the embodiments have been described above, it will be understood that various changes in form and detail are possible without departing from the spirit and scope of the claims.

This application claims priority from Basic Application No. 2021-178622 filed with the Japan Patent Office on November 1, 2021, the entire contents of which are incorporated herein by reference.

1 communication system 100 communication device 110 communication device (other communication device)
110a communication device (an example of a first communication device)
110b communication device (an example of a second communication device)
500 control unit 501 communication unit 502 storage unit 503 acquisition unit 504 determination unit 505 switching unit 506 change unit 510 control unit 511 communication unit 513 reception unit 514 setting unit

Claims (16)

1. A communication device capable of communicating with another communication device having the same spread spectrum SF value,
   A communication device that communicates with another communication device while switching a plurality of SF values in a time division manner.
2. The communication device according to claim 1, wherein the plurality of SF values are arbitrary values within a range of SF values that can be set for the communication device.
3. The communication device according to claim 1 or 2, wherein the SF value is a setting value set in the other communication device by an installer who installs the other communication device.
4. The communication device according to any one of claims 1 to 3, wherein the communication device performs communication by switching the SF value at a switching timing determined for each SF value.
5. The communication device
   changing the SF value at predetermined time intervals to determine whether communication with the other communication device is possible;
   Determining the plurality of SF values based on the determination result of the communication availability;
   5. A communication device according to any one of claims 1-4.
6. 6. The communication device according to claim 5, wherein the communication device changes the plurality of SF values based on the radio wave condition, the communication congestion condition, or the distance from the other communication device.
7. The communication device according to any one of claims 1 to 6, wherein said communication device can externally set said plurality of SF values.
8. 8. The communication device changes the SF value at predetermined time intervals, and determines the timing of switching the plurality of SF values based on the time when the communication with the other communication device is performed. The communication device according to any one of Claims 1 to 3.
9. The communication device according to claim 8, wherein the communication device changes the timing of switching the plurality of SF values according to radio wave conditions or congestion conditions of the communication.
10. The communication device according to any one of claims 1 to 9, wherein the communication device can externally set timing for switching the plurality of SF values.
11. A communication system comprising the communication device according to any one of claims 1 to 10 and another communication device,
    The communication system, wherein the other communication device communicates with the communication device using the SF value set in the other communication device.
12. The other communication device comprises a first communication device to which a first SF value is set and a second communication device to which a second SF value different from the first SF value is set. 12. The communication system of claim 11, comprising:
13. The communication system according to claim 11 or 12, wherein said another communication device transmits data to said communication device according to a set transmission schedule.
14. The other communication device is
    If there is no response from the communication device after transmitting the data to the communication device, determining that communication is abnormal and holding the data;
    retransmitting the held data to the communication device when the communication abnormality is resolved;
    14. A communication system according to any one of claims 11-13.
15. A communication device capable of communicating with another communication device having the same spread spectrum SF value,
    Communicate with other communication devices while switching multiple SF values in a time division manner.
    Communication method.
16. A communication device capable of communicating with another communication device having the same spread spectrum SF value,
    Communicate with other communication devices while switching multiple SF values in a time division manner.
    program.

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