JP7578641B2 - Transmitting device, transmitting method, and receiving device - Google Patents

Description

The present invention relates to a transmitting device and method for transmitting data, and a receiving device for receiving data, and in particular to a data communication technology using a frequency hopping method.

A frequency hopping method is known as a method of wireless data communication. For example, the following Patent Document 1 discloses a technology for performing wireless data communication by the frequency hopping method using the 2.4 GHz (gigahertz) band.

JP 2009-88943 A

Here, in a conventional frequency hopping method using the 2.4 GHz band, such as BLE (Bluetooth Low Energy: registered trademark), the frequency channel switching cycle is relatively short, such as every 1.6 ms (milliseconds), and data is transmitted once on each frequency channel.

On the other hand, in recent years, communication technology that uses the 920 MHz (megahertz) band for wireless data communication has been attracting attention. In 920 MHz band communication, the standard stipulates that the frequency channel switching period is longer than in the case of 2.4 GHz band communication. For example, switching is performed at a relatively slow speed, such as every 200 ms.

When a frequency hopping method is adopted that switches frequency channels relatively slowly, such as the 920 MHz band standard mentioned above, there is a risk that the required data transfer rate will not be met if data is transmitted once per frequency channel, as in the conventional 2.4 GHz band method.

The present invention was made in consideration of the above circumstances, and aims to improve the data transfer rate when transmitting data using the frequency hopping method.

The transmitting device of the present invention is a transmitting device that transmits data using a frequency hopping method, and comprises a transmitting unit that transmits data, and a transmission control unit that controls the transmitting unit to transmit data multiple times in each frequency channel that is switched by frequency hopping , wherein the frequency switching period is constant, the number of data transmissions in each of the frequency channels and the data transmission time length per data transmission are the same, and when the number of data transmissions for each frequency channel is c, the data transmission time length is t, and the length of a repeating transmission period, which is each period formed by dividing one frequency period, which is the period between the switching timings of the frequency channel, into c equal parts, is f, the transmission control unit varies the data transmission intervals by varying the slots in which data is transmitted, among f/t slots formed by dividing the repeating transmission period into f/t equal parts, between at least some of the repeating transmission periods .
This increases the amount of data transmitted per frequency channel.

Furthermore, a transmission method according to the present invention is a transmission method in a transmitting device that transmits data by a frequency hopping system, in which data transmission is performed a plurality of times in each frequency channel that is switched by frequency hopping, and a frequency switching period is constant, the number of data transmissions in each of the frequency channels and the data transmission time length per data transmission are the same, and when the number of data transmissions for each frequency channel is c, the data transmission time length is t, and the length of a repeating transmission period that is each period formed by dividing one frequency period that is the period between frequency channel switching timings into c equal parts is f, the transmission method varies the data transmission interval by making the slots in which data transmission is performed among f/t slots formed by dividing the repeating transmission period into f/t equal parts, among at least some of the repeating transmission periods .
With such a transmission method, the same effect as that of the above-described transmission device according to the present invention can be obtained.

Moreover, a receiving device according to the present invention is a receiving device that receives data transmitted by a transmitting device using a frequency hopping method, and includes a receiving unit that receives data, and a receiving control unit that controls the receiving unit to receive data transmitted multiple times by the transmitting device in each frequency channel that is switched by frequency hopping, wherein when a frequency switching period is constant, the number of data transmissions in each of the frequency channels and the data transmission time length per data transmission are the same, and the number of data transmissions for each frequency channel is c, the data transmission time length is t, and the length of a repeating transmission period, which is each period formed by dividing one frequency period, which is the period between frequency channel switching timings, into c equal parts, is f, the receiving control unit controls the receiving unit to receive data transmitted by the transmitting device with different data transmission intervals by varying the slots for data transmission among f/t slots formed by equally dividing the repeating transmission period into f/t parts, among at least some of the repeating transmission periods .
This increases the amount of data received per frequency channel.

According to the present invention, when data communication is performed using the frequency hopping method, it is possible to improve the data transfer rate.

FIG. 1 is a block diagram illustrating an example of the configuration of a communication system according to a first embodiment. FIG. 1 is an explanatory diagram of frequency channel switching in a frequency hopping system. FIG. 11 is an explanatory diagram of an example of a technique for transmitting data multiple times for each frequency channel. FIG. 11 is an explanatory diagram of an example of a method for varying data transmission intervals. FIG. 4 is an explanatory diagram of a slot in the embodiment. FIG. 11 is a diagram showing an example of transmission slot pattern group information. FIG. 4 is a diagram illustrating an example of transmission data in the embodiment. 10 is a flowchart illustrating an example of a specific process procedure to be executed by a transmission control unit to realize a communication method according to a first embodiment. 10 is a flowchart illustrating an example of a specific processing procedure to be executed by a reception control unit to realize a communication method according to a first embodiment. 13 is a flowchart of a process executed by a reception control unit to deal with a reception error. FIG. 11 is a block diagram illustrating an example of the configuration of a communication system according to a second embodiment. 10 is a flowchart illustrating an example of a processing procedure for implementing a communication method according to a second embodiment.

Hereinafter, embodiments of the present invention will be described in the following order.
1. First embodiment
(1-1. Configuration of communication system)
(1-2. Communication method as an embodiment)
(1-3. Processing Procedure)
<2. Second embodiment>
3. Modifications
4. Summary of the embodiment

1. First embodiment
(1-1. Configuration of communication system)
FIG. 1 is a block diagram for explaining an example of the configuration of a communication system 100 according to a first embodiment, and shows an example of the internal configuration of each of a transmitter 1 and a receiver 20 that constitute the communication system 100. As shown in FIG.
The communication system 100 as an embodiment is configured as a system that performs wireless data communication between a transmitter 1 and a receiver 20 by a frequency hopping method. In this example, the case where such a communication system 100 is applied to a radio control system for remotely controlling a controlled object 2 such as a model airplane, a model car, or various robots is illustrated. In this case, the transmitter 1 is configured as a device that receives an operation input from an operator and transmits operation information to a receiver 20 provided in the controlled object 2. The controlled object 2 is provided with an actuator 26 for driving a movable mechanism (not shown). For example, in the case of a model car, the movable mechanism in the controlled object 2 is a steering mechanism or a wheel drive mechanism, and in the case of a model airplane, the propeller rotation mechanism or a drive mechanism for movable wings such as ailerons and rudder is. In addition, in the case of a robot, the movable mechanism of various joints is also applicable. For example, an actuator for driving the above-mentioned movable mechanism, such as a motor or a solenoid, is used as the actuator 26.

In this example, the radio wave band used in the communication system 100 is, for example, 920 MHz (megahertz) band. Furthermore, the frequency CH (channel) switching period in frequency hopping is, for example, 200 ms (milliseconds).

As shown in the figure, the transmitter 1 includes an operation unit 11 , an encoder 12 , a transmission control unit 13 , a memory unit 14 , a transmission unit 15 , and an antenna 16 .
The operation unit 11 collectively refers to operators for performing various operations related to the control of the controlled body 2. Examples of operators provided in the operation unit 11 include various levers, buttons, dials (wheels), touch sensors, and the like.
The "operations related to control" referred to here is not limited to operations for directly instructing the control content, but also includes operations for setting various operations of the transmitter 1 and the receiver 20, such as setting the sensitivity of an operator for instructing the control amount of a lever or the like (the correspondence between the control amount and the control amount).
The operation unit 11 outputs to the encoder 12 a signal (operation signal) indicating operation information corresponding to the operation of the operator.

The user interface realized by the operation unit 11 may be a GUI (Graphical User Interface). In that case, the transmitter 1 is provided with a display unit such as a liquid crystal display or an organic EL (Electro-Luminescence) display, and the user as the operator performs operations for various settings, for example, according to a menu screen displayed on the display unit.

The encoder 12 encodes the operation signal from the operation unit 11 into operation data in a predetermined data format and outputs it to the transmission control unit 13.

The transmission control unit 13 is configured with a microcomputer equipped with, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and the CPU performs overall control of the transmitter 1 by executing processes according to programs stored in memory such as the ROM. It mainly performs various controls for transmitting data to the receiver 20 using the frequency hopping method.

Specifically, the transmission control unit 13 controls the operation of the transmission unit 15 .
The transmitting unit 15 is configured to be capable of transmitting data by a frequency hopping method, and is capable of switching the frequency of the radio waves transmitted from the antenna 16 .
The transmission control unit 13 generates transmission data including the operation data input from the encoder 12 , and causes the transmission unit 15 to transmit the transmission data to the receiver 20 .
A specific example of a data transmission method according to an embodiment will be described later.

The transmission control unit 13 is connected to a memory unit 14, which is composed of a non-volatile memory such as a flash memory. The memory unit 14 is used to store various data used by the transmission control unit 13 when executing various processes. In particular, the memory unit 14 in this example stores transmission slot pattern group information Is, which will be explained later.

Here, the transmission control unit 13 may execute processing for the various operation settings described above based on the operation data input from the encoder 12.

Next, the controlled object 2 will be described.
As shown, the controlled object 2 includes a receiver 20 and an actuator 26 .
The receiver 20 includes an antenna 21 , a receiving section 22 , a reception control section 23 , a memory section 24 , and a decoder 25 .

The receiver 22 receives the transmission data from the transmitter 1 via the antenna 21. To support data communication using the frequency hopping method, the receiver 22 has a receiving frequency switching function.

The reception control unit 23 is configured with, for example, a microcomputer equipped with a CPU, ROM, RAM, etc., and the CPU executes processes according to programs stored in a memory such as the ROM to perform overall control of the receiver 20, mainly various controls for receiving data by the frequency hopping method. Specifically, the reception control unit 23 controls the sequential switching of the reception frequency by the receiving unit 22 in order to realize data reception by the frequency hopping method.
A specific example of a data receiving method according to an embodiment will be described later.

The reception control unit 23 also acquires operation data contained in the transmission data from the transmitter 1 received by the reception unit 22, and performs processing to output the operation data to the decoder 25.

The memory unit 24 is composed of a non-volatile memory, such as a flash memory, connected to the reception control unit 23, and is used to store various data used by the reception control unit 23 to execute various processes. In particular, the memory unit 24 in this example stores the transmission slot pattern group information Is.

The decoder 25 decodes the operation data input from the reception control unit 23 to obtain a drive control signal for the actuator 26 .
The actuator 26 is driven based on this drive control signal. As a result, the movable mechanism in the controlled object 2 is driven in response to the operation of the operation unit 11 in the transmitter 1, and the controlled object 2 moves in response to the operation of the operator. In other words, the controlled object 2 is controlled.

In the communication system 100 configured as described above, pre-processing is performed as pre-processing before starting data communication between the transmitter 1 and the receiver 20. This pre-processing is performed based on a user operation via the operation unit 11, for example.
In this pre-processing, a frequency switching pattern in the frequency hopping method is shared between the transmitter 1 and the receiver 20 .

For confirmation, frequency CH switching in the frequency hopping method will be described with reference to FIG.
As shown in the figure, in this example, the frequency CHs used in frequency hopping are 22, for example, CH1 to CH22. In this case, the frequency switching pattern refers to a pattern regarding the order in which these 22 frequency CHs are switched.

In the figure, the dotted vertical lines represent the frequency switching period in frequency hopping. As described above, in this example, the frequency switching period is 200 ms.
In the following description, the period between frequency switching timings in frequency hopping is referred to as "one frequency period" as shown in the figure.

In this example, the 22 frequency channels are switched in sequence with a frequency switching period of 200 ms. In this case, the repetition period of the same frequency channel, indicated by the dashed line in the figure, is 4.4 s.

(1-2. Communication method as an embodiment)
As mentioned above, in a conventional frequency hopping method using the 2.4 GHz band, such as BLE (Bluetooth Low Energy: registered trademark), the frequency channel switching period is a relatively short period, such as 1.6 ms, and data is transmitted once on each frequency channel.

On the other hand, when performing wireless data communication using the 920 MHz band as in this example, the standard requires that the frequency channel switching period be made longer than when performing communication in the 2.4 GHz band.
Specifically, the realistic number of frequency channels in the 920 MHz band is approximately 20 to 30, and the following conditions are set forth in the 920 MHz band specific low power wireless standard in Japan.
1) The total data transmission time for all frequency channels per hour is set to 720 seconds or less (i.e., the transmission duty per wireless equipment is set to 20% or less).
2) The total data transmission time per hour on one frequency channel is 36 seconds or less (i.e., the transmission duty per frequency channel is 1% or less).
3) Continuous transmission time on one frequency channel shall be 400 ms or less, and transmission shall be suspended for 4 seconds or more before the next data transmission on that frequency channel.

In particular, because of condition 3) above, in frequency hopping wireless communications using the 920 MHz band, it is required to lengthen the frequency channel switching period.

When it is required to switch frequency channels at a relatively slow speed, as in the case of a frequency hopping method in the 920 MHz band, there is a risk that the required data transfer rate may not be met if data is transmitted only once per frequency channel, as in the conventional 2.4 GHz band method.
In particular, when applying to a radio control system as in this example, if the transfer rate of the operation data decreases, it may lead to a deterioration in the controllability of the controlled object 2, so it is necessary to improve the data transfer rate.

Therefore, in this embodiment, a method is adopted in which data transmission is performed multiple times in each frequency CH, as shown in FIG.
In the example of FIG. 3, in order to improve the data transfer rate while satisfying the conditions of the above-mentioned communication standard, data transmission of 2 ms is performed 20 times per frequency CH.
By transmitting data multiple times in each frequency CH in this manner, the amount of data transmitted per frequency CH can be increased, and the data transfer rate can be improved when data communication is performed using the frequency hopping method.

Here, the number of data transmissions for each frequency channel is set to "c" (20 times in the example of FIG. 3).
In the following description, the c periods formed by dividing one frequency period into c equal parts will be referred to as a "repeated transmission period."
In this example, one frequency period=200 ms, so the repeat transmission period is 10 ms if c=20.

3 shows an example in which data transmission is performed in the first 2 ms period in each repeated transmission period within one frequency period, but if the period in which data transmission is performed within each repeated transmission period is fixed in this manner, there is a possibility that reception errors will occur consecutively if another communication system 100 that communicates by frequency hopping is present relatively nearby and the frequency CH used by this other communication system 100 overlaps. In other words, there is a risk that a period in which the receiver 20 cannot receive transmitted data consecutively will continue over one frequency period.
In addition, in the frequency hopping method, the same frequency CH is selected in the repetition cycle of the same frequency CH as shown in FIG. 2 above. Therefore, if the frequency CH overlaps with that of another communication system 100, there is a risk that a reception error will occur again when the same frequency CH is selected again thereafter.

Therefore, in this embodiment, in order to suppress the occurrence frequency of reception errors, a method is adopted in which at least some of the data transmission intervals are made different for multiple data transmissions performed for each frequency CH, as shown in FIG.
Specifically, in this example, the data transmission interval is changed randomly for multiple data transmissions performed for each frequency CH.

By varying the data transmission interval for each frequency CH as described above, it is possible to reduce the likelihood of consecutive reception errors occurring, and it is possible to achieve both an improvement in the data transfer rate by transmitting data multiple times for each frequency CH and an improvement in communication stability.
In addition, by randomly changing the data transmission interval, it is possible to further reduce the possibility of data transmission timing overlapping with other transmitters 1, thereby enhancing the effect of improving communication stability.

A specific method for varying the data transmission interval for each frequency CH as described above will now be described with reference to FIGS.
FIG. 5 is an explanatory diagram of the slot SL.
A slot SL is a period formed by equally dividing the repeat transmission period into f/t when the length of the repeat transmission period is "f" (10 ms in this example) and the data transmission time length per data transmission is "t" (2 ms in this example).

In this embodiment, a method is adopted in which each repeat transmission period is divided into a plurality of slots SL, and the slots SL in which data transmission is performed are made different in at least some of the repeat transmission periods, thereby making the data transmission intervals different.
Specifically, in this example, the slot SL in which data transmission is performed is randomly changed for each repeat transmission period, thereby randomly changing the data transmission interval.

In this embodiment, the transmission control unit 13 uses the transmission slot pattern group information Is shown in FIG. 1 to vary the data transmission interval as described above.

FIG. 6 is a diagram showing an example of the transmission slot pattern group information Is.
The transmission slot pattern group information Is is information including a plurality of "transmission slot pattern information". The "transmission slot pattern information" is information that determines, for each repeating transmission period, "transmission slots" that are slots for transmitting data among the f/t number of slots SL.
This "transmission slot pattern information" can be said to be information that defines a transmission slot for each number of transmissions in one frequency period. The number of transmissions here can be said to be an identifier of a repeat transmission period in one frequency period.

The transmission slot pattern group information Is is configured to include a plurality of types of transmission slot pattern information having different patterns of allocating transmission slots to a repeated transmission period (number of transmissions) as the transmission slot pattern information as described above.
Specifically, in the transmission slot pattern group information Is in this example, the transmission slots are randomly assigned to the repeating transmission period in each transmission slot pattern information, and this random assignment can be performed based on a pseudo-random number sequence such as a Reed-Solomon sequence.

Here, in the transmission slot pattern group information Is, an identifier for identifying each piece of transmission slot pattern information is expressed as a "pattern identifier".
As shown in the figure, the transmission slot pattern group information Is in this example is configured as information including a plurality of types of transmission slot pattern information as well as a pattern identifier for each of the transmission slot pattern information.

The transmission control unit 13 in the transmitter 1 controls the data transmission timing for each repeated transmission period (for each transmission count) in accordance with one piece of transmission slot pattern information selected from the above-mentioned transmission slot pattern group information Is.
This makes it possible to randomly change the slot SL in which data is transmitted for each repeat transmission period, and to randomly change the data transmission interval.

In this embodiment, the transmission control unit 13 in the transmitter 1 and the reception control unit 23 in the receiver 20 share transmission slot pattern information to be applied to the data communication before the start of the data communication. This sharing is performed, for example, during the pre-processing described above.
Specifically, the transmission control unit 13 causes the transmitting unit 15 to transmit to the receiving control unit 23 a pattern identifier indicating the transmission slot pattern information selected by itself during the pre-processing.

The reception control unit 23, which has received the pattern identifier, refers to the transmission slot pattern group information Is stored in the memory unit 24 to identify the transmission slot pattern information indicated by the pattern identifier. After data communication starts, the reception control unit 23 causes the reception unit 22 to perform a reception operation according to the identified transmission slot pattern information. Specifically, in each repeated transmission period, the reception control unit 23 instructs the reception unit 22 to set a reception window with a period length corresponding to the transmission slot indicated by the identified transmission slot pattern information, and causes the reception operation of the transmission data to be performed. The reception window here refers to the period during which the reception unit 22 performs the reception operation. By setting the reception window to a period corresponding to the transmission slot, it is possible to prevent transmission data from being erroneously received by other communication systems 100.

In this example, as a measure to be taken when a reception error occurs in the transmission data at the receiver 20, the transmission control unit 13 performs processing to include the number of transmissions and a pattern identifier in the transmission data. Specifically, the transmission control unit 13 performs processing to transmit, as the transmission data for each repeated transmission period, transmission data including a pattern identifier indicating the selected transmission slot pattern information and information indicating the number of data transmissions.

FIG. 7 shows an example of the transmission data.
In this example, operation data is transmitted to the receiver 20. Therefore, by carrying out the above-mentioned process, the transmission data in this case includes information on the operation data, the pattern identifier, and the number of transmissions. At this time, it is considered that the information on the pattern identifier and the number of transmissions is stored in an area, such as a header area in the transmission data, that is different from the actual data area (the storage area for the operation data in this example).

When a reception error occurs on the receiver 20 side, it becomes difficult to accurately grasp the number of transmissions in one frequency period. Specifically, the reception control unit 23 in this example recognizes the number of transmissions by counting the number of times transmission data is received by the receiving unit 22, but in this case, when a reception error occurs, it becomes difficult to accurately grasp the number of transmissions.
Furthermore, the transmission slot pattern information applied to the data communication may be changed after the start of the data communication on the transmitter 1 side. Depending on the timing or period during which a reception error occurs, it may be possible that the receiver 20 side cannot recognize such a change in the transmission slot pattern information.

By including information on the number of transmissions in each transmission data as described above, even if the number of receptions (number of transmissions) counted by receiver 20 does not match the actual number of transmissions due to the occurrence of a reception error, it is possible to recognize the exact number of transmissions, and the transmission data can be received at the appropriate slot timing corresponding to the current number of transmissions.
Furthermore, by including a pattern identifier in each transmission data as described above, the transmitter 1 can notify the receiver 20 of the selected transmission slot pattern, so that the receiver 20 can appropriately select a slot for each repeated transmission period and appropriately receive the transmission data.

(1-3. Processing Procedure)
A specific example of a process procedure to be executed by the transmission control unit 13 and the reception control unit 23 to realize the communication method according to the first embodiment described above will be described with reference to the flowcharts of FIGS.

FIG. 8 is a flowchart showing the process of the transmission control unit 13.
The process shown in Fig. 8 is started after the above-mentioned pre-processing is completed. That is, at the time when the process shown in Fig. 8 is started, the transmission slot pattern information to be applied is in a shared state between the transmitter 1 and the receiver 20.

First, in step S101, the transmission control unit 13 resets the number of transmissions n to 0. The number of transmissions n means the number of times transmission data is transmitted within one frequency period.

In step S102 following step S101, the transmission control unit 13 acquires the pattern identifier of the selected transmission slot pattern information, and in the further following step S103, generates transmission data including the acquired transmission slot pattern information and the current transmission count n. That is, as described above in FIG. 7, the transmission data is generated including the pattern identifier, the transmission count n, and the operation data.

Then, in step S104 following step S103, the transmission control unit 13 causes the transmission data to be transmitted at the timing of the slot corresponding to the current transmission count n. In other words, the transmission unit 15 transmits the generated transmission data at the timing of the slot SL associated with the current transmission count n in the transmission slot pattern information being applied.

In step S105 following step S104, the transmission control unit 13 determines whether or not the repeat transmission period has ended. That is, in this example, it is determined whether or not a time of 10 ms has elapsed (see FIG. 5).
If it is determined in step S105 that the repeated transmission period has not ended, the transmission control unit 13 proceeds to step S106 and determines whether a transmission process end condition has been satisfied. The transmission process end condition means a predetermined condition that is determined in advance as a condition for ending the data transmission process to the receiver 20 side, such as the power supply being turned off for the transmitter 1, for example.
If it is determined that the transmission process end condition is not satisfied, the transmission control unit 13 returns to step S105. That is, depending on the processes of steps S105 and S106, a loop process is formed in which the transmission control unit 13 waits for either the end of the repeated transmission period or the satisfaction of the transmission process end condition.

If it is determined in step S105 that the repeated transmission period has ended, the transmission control unit 13 proceeds to step S107 and determines whether or not it is time to switch the frequency channel. That is, it determines whether or not the frequency channel switching timing in frequency hopping has arrived. This process can be performed as a determination of whether or not the number of transmissions n has reached the number of data transmissions c (20 in this example) for each frequency channel.
If it is determined that it is not the timing to switch frequency channels, the transmission control unit 13 proceeds to step S108, increments the number of transmissions n by 1 (n←n+1), and returns to step S102.
As a result, within one frequency period, the processes of steps S102 to S104 are executed for each repeated transmission period to transmit the transmission data, and the number of transmissions n is counted in step S108.

Also, if it is determined in step S107 that it is time to switch frequency channels, the transmission control unit 13 returns to step S101. This causes the number of transmissions n to be reset to 0 for each frequency channel (i.e., for each frequency period).

If the transmission control unit 13 determines in step S106 that the transmission process termination condition is met, it ends the series of processes shown in FIG. 8.

FIG. 9 is a flowchart showing the process of the reception control unit 23.
The process shown in FIG. 9 is also started after the pre-processing described above is completed. Therefore, at the time when the process shown in FIG. 9 is started, the transmission slot pattern information to be applied is shared between the transmitter 1 and the receiver 20.

In FIG. 9, in step S201, the reception control unit 23 resets the number of receptions m to 0. Then, in the following step S202, the reception control unit 23 identifies the slot number (i.e., the transmission slot) associated with the number of transmissions matching the number of receptions m in the selected transmission slot pattern information, and in the following step S203, issues an instruction to execute a reception operation using the reception window corresponding to the identified slot number. That is, the reception unit 22 is instructed to set a reception window corresponding to the identified transmission slot, and is caused to execute a reception operation of the transmission data.

In step S204 following step S203, the reception control unit 23 determines whether or not the repeated transmission period has ended.
If it is determined in step S204 that the repeated transmission period has not ended, the reception control unit 23 proceeds to step S205 to determine whether a reception process end condition has been met. The reception process end condition refers to a predetermined condition that is determined in advance as a condition for ending the reception process of the transmission data from the transmitter 1, such as a notification of the end of data transmission from the transmitter 1 or the power being turned off for the receiver 20.
If it is determined that the reception process end condition is not satisfied, the reception control unit 23 returns to step S204. That is, depending on the processing of steps S204 and S205, a loop process is formed that waits for either the end of the repeated transmission period or the satisfaction of the reception process end condition.

If it is determined in step S204 that the repeated transmission period has ended, the reception control unit 23 proceeds to step S206, where it determines whether it is time to switch frequency channels. If it is determined that it is not time to switch frequency channels, it proceeds to step S207, increments the number of receptions m by 1 (m←m+1), and returns to step S202.
As a result, in one frequency period, the processes of steps S202 and S203 are executed for each repeated transmission period, so that the transmission data is received at an appropriate timing, and the number of times of reception m is counted in step S207.

Also, if it is determined in step S206 that it is time to switch frequency channels, the reception control unit 23 returns to step S201. This causes the number of receptions m to be reset to 0 for each frequency channel (i.e., for each frequency period).

If the reception control unit 23 determines in step S205 that the reception process termination condition is met, it ends the series of processes shown in FIG. 9.

FIG. 10 is a flow chart showing a process for dealing with reception errors in the receiver 20. As shown in FIG.
The reception control unit 23 executes the process shown in FIG. 10 in parallel with the process shown in FIG.

In step S250, the reception control unit 23 waits for a reception error to occur, and if a reception error occurs, in step S251, it instructs the reception unit 22 to execute a reception operation with the reception window maximized. That is, it instructs the reception unit 22 to set the reception window maximized to the full length of the repeated transmission period, and executes the reception operation.

In step S252 following step S251, the reception control unit 23 determines whether reception was successful, i.e., whether the transmission data was received by the reception operation with the reception window maximized, and if it is determined that reception was not successful, the process returns to step S251. In other words, the reception operation with the reception window maximized is repeatedly executed until reception is successful.

If it is determined in step S252 that reception is successful, the reception control unit 23 proceeds to step S253, where it acquires the pattern identifier and the number of transmissions included in the received data. Then, in the following step S254, the reception control unit 23 selects the transmission slot pattern information indicated by the acquired pattern identifier, and in the following step S255, it performs a process of correcting the number of receptions m based on the acquired number of transmissions. That is, it performs a process of correcting the number of receptions m to the value of the acquired number of transmissions + 1. Note that if the acquired number of transmissions is c, the number of receptions m is set to 0.
By carrying out the above-described process of correcting the number of receptions m, from the next repeated transmission period, it is possible to perform reception operations with the reception window shortened to a period corresponding to the transmission slot, thereby preventing erroneous reception of transmission data by other communication systems 100.

After executing the correction process in step S255, the reception control unit 23 ends the series of processes shown in FIG.

<2. Second embodiment>
Next, a second embodiment will be described.
The second embodiment aims to prevent the transmission slot pattern applied to other communication systems from overlapping.
In the following description, parts that are similar to parts that have already been described will be given the same reference numerals and description thereof will be omitted.

FIG. 11 is a block diagram for explaining an example of the configuration of a communication system 100A according to the second embodiment.
As shown in the figure, the communication system 100A includes a transmitter 1A and a controlled object 2 including a receiver 20 as described in the first embodiment.

The transmitter 1A differs from the transmitter 1 of the first embodiment in that a receiver 18 is added and that a transmission control unit 13A is provided instead of the transmission control unit 13.
The receiving unit 18, like the receiving unit 22, has a receiving frequency switching function to accommodate data communication using the frequency hopping method, and receives data transmitted by another transmitter 1A (or transmitter 1) via the antenna 16.

The transmission control unit 13A is similar to the transmission control unit 13 in that it executes the processing shown in Figure 8 above, but differs from the transmission control unit 13 in that it executes the following processing based on the data received by the receiving unit 18.
That is, before starting data transmission to the receiver 20, the transmission control unit 13A causes the receiving unit 18 to execute a receiving operation of the transmission data of the other transmitter 1A (or transmitter 1: similar to the second embodiment below), and based on the pattern identifier contained in the transmission data of the other transmitter 1A, determines whether or not the transmission slot pattern information selected by the other transmitter 1A matches the transmission slot pattern information that was to be applied by the own device, and if it is determined that the two match, performs a process of selecting another transmission slot pattern information from the transmission slot pattern group information.

An example of a specific processing procedure of the transmission control unit 13A for implementing the communication method according to the second embodiment will be described with reference to the flowchart of FIG.
The transmission control unit 13A starts the process shown in FIG. 12, for example, before the start of the transmission process of the transmission data to the receiver 20.

In step S301, the transmission control unit 13A issues an instruction to execute a receiving operation by the receiving unit 18 as an instruction to execute a receiving operation. As an example of this receiving operation, it is possible to maximize the receiving window described above and execute the operation.

In step S302 following step S301, the transmission control unit 13A determines whether data has been received and whether the received data includes a pattern identifier. That is, the transmission control unit 13A determines whether data has been received by the receiving operation executed in step S301 and whether the received data includes a pattern identifier.
If it is determined that no data has been received, or that data has been received but the received data does not include a pattern identifier, and the condition of step S302 is not satisfied, the transmission control unit 13A terminates the series of processes shown in Figure 12.

On the other hand, if it is determined in step S302 that data has been received and that the received data contains a pattern identifier, the transmission control unit 13A proceeds to step S303 and determines whether the pattern identifier matches the transmission slot pattern information to be applied. In other words, it determines whether the pattern identifier of the transmission slot pattern information in the transmission slot pattern group information Is that was to be applied by the transmission control unit 13A matches the pattern identifier included in the received data (i.e., the pattern identifier representing the transmission slot pattern information being applied by the other communication system 100A or 100).

If it is determined in step S303 that the transmission slot pattern information to be applied does not match the pattern identifier, the transmission control unit 13A proceeds to step S304 and selects the transmission slot pattern information to be applied from the transmission slot pattern group information Is. In other words, in this case, the transmission slot pattern information to be applied by the transmission control unit 13A does not overlap with the transmission slot pattern information being applied by the other communication system 100A (or 100), so the transmission slot pattern information to be applied is selected.

On the other hand, if it is determined in step S303 that the transmission slot pattern information to be applied matches the pattern identifier, the transmission control unit 13A proceeds to step S305 and selects another transmission slot pattern information (a transmission slot pattern information different from the transmission slot pattern information to be applied) from the transmission slot pattern group information Is. This prevents the transmission slot patterns to be applied from overlapping with those of other communication systems 100A (or 100).

The transmission control unit 13A ends the series of processes shown in FIG. 12 in response to execution of either the process of step S304 or the process of step S305.

3. Modifications
Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned specific examples, and various modified configurations can be adopted.
For example, in the above embodiment, the present invention is applied to data communication in a radio control system, but the present invention can be widely and suitably applied to communication systems that perform wireless data communication using a frequency hopping method.

Furthermore, the values exemplified in the embodiments for the radio band used in wireless data communication, the number of frequency channels, the number of data transmissions c, the length of the repeated transmission period f, and the data transmission time length t are merely examples and are not limited to these values.

4. Summary of the embodiment
As described above, the transmitting device (transmitter 1, 1A) as an embodiment is a transmitting device that transmits data using a frequency hopping method, and includes a transmitting unit (same as 15) that transmits data, and a transmission control unit (same as 13, 13A) that controls the transmitting unit to transmit data multiple times on each frequency channel switched by frequency hopping (see Figures 3, 4, etc.).
This increases the amount of data transmitted per frequency channel.
Therefore, when data communication is performed by the frequency hopping method, the data transfer rate can be improved.

In addition, in the transmitting device according to the embodiment, the transmission control unit varies at least some of the data transmission intervals for multiple data transmissions performed for each frequency channel (see FIG. 4, etc.).
When another communication system that communicates by frequency hopping is present relatively nearby, there is a possibility that the frequency channel overlaps with this other communication system, resulting in an error in receiving the transmitted data on the receiving device side. However, when data transmission is performed multiple times for each frequency channel as in the present invention, there is a possibility that reception errors will occur continuously when the frequency channel overlaps with the other communication system. In other words, there is a risk that the period during which the receiving device cannot continuously receive the transmitted data will continue for the period of one frequency channel. Therefore, at least some of the data transmission intervals are made different for the multiple data transmissions performed for each frequency channel as described above.
This makes it possible to reduce the occurrence of consecutive reception errors, and by transmitting data multiple times for each frequency channel, it is possible to achieve both an improvement in data transfer rate and an improvement in communication stability.

Furthermore, in the transmitting device of the embodiment, the frequency switching period is constant, the number of data transmissions in each frequency channel and the data transmission time length per data transmission are the same, and the number of data transmissions per frequency channel is c, the data transmission time length is t, and the length of the repeating transmission period, which is each period formed by dividing one frequency period, which is the period between frequency channel switching timings, into c equal parts, is f. The transmission control unit differs the data transmission intervals by differing the slots in which data is transmitted among the f/t slots (same SL) formed by dividing the repeating transmission period into f/t equal parts, during at least some of the repeating transmission periods (see Figure 5, etc.).
This makes it possible to vary at least some of the data transmission intervals in each frequency channel by a simple process of varying the slots in which data transmission is performed during some of the repetitive transmission periods.
Therefore, the processing load can be reduced in the transmission control process for improving communication stability by varying the data transmission interval.

Furthermore, in the transmitting device as an embodiment, a storage unit (memory unit 14) is provided in which transmit slot pattern group information (Is) is stored as transmit slot pattern information, which is information that defines, for each repeating transmission period, which transmit slots among the f/t slots are used for data transmission, and which is information that includes multiple types of transmit slot pattern information with different transmit slot allocation patterns for the repeating transmission period, and the transmission control unit causes the transmitting unit to execute data transmission for each repeating transmission period in accordance with one transmit slot pattern information selected from the transmit slot pattern group information (see Figures 6, 8, etc.).
This allows the transmission slot pattern to be switched to a different pattern.
Therefore, it is possible to make it difficult for the transmission slot patterns to overlap with other communication systems, thereby reducing the frequency of reception errors and further improving communication stability.

In addition, in the transmitting device as an embodiment, the transmission control unit transmits transmission data including a pattern identifier indicating the selected transmission slot pattern information and information indicating the number of times data is transmitted as transmission data for each repeated transmission period (see Figures 7, 8, etc.).
By including a pattern identifier in the transmission data, the transmitting device can notify the receiving device of the transmission slot pattern being selected, and the receiving device can select an appropriate slot for each repeated transmission period, so that the transmitting data can be properly received. Also, by including information indicating the number of data transmissions in the transmission data, even if the receiving device becomes unable to receive the transmission data midway and the number of receptions (number of transmissions) counted by the receiving device does not match the actual number of transmissions, the accurate number of transmissions can be recognized, and the transmitting data can be received at the timing of the appropriate slot corresponding to the current number of transmissions.

Furthermore, in the transmitting device (transmitter 1A) of the embodiment, a receiving unit (18) that receives data is provided, and a transmission control unit (13A) causes the receiving unit to execute a receiving operation of the transmission data of the other transmitting device before starting data transmission to the receiving device, and determines whether or not the transmission slot pattern information selected by the other transmitting device matches the transmission slot pattern information that was to be applied by the own device based on a pattern identifier included in the transmission data of the other transmitting device, and if it is determined that the two match, selects another transmission slot pattern information from the transmission slot pattern group information (see Figures 11, 12, etc.).
This makes it possible to prevent the transmission slot pattern from overlapping with that of another transmitting device before data transmission to the receiving device starts.
Therefore, it is possible to avoid the occurrence of reception errors caused by overlapping transmission slot patterns with other transmitting devices, and it is possible to improve communication stability.

Furthermore, in the transmitting device (transmitter 1, 1A) of the embodiment, the transmission control section (transmitter 13, 13A) randomly changes the data transmission interval for multiple data transmissions performed for each frequency channel.
By randomly varying the data transmission interval, it is possible to further reduce the possibility that data transmission timing will overlap with other transmitting devices.
Therefore, the frequency of occurrence of reception errors can be further reduced, and the effect of improving communication stability can be enhanced.

The transmission method according to the embodiment is a transmission method in a transmission device that performs data transmission by frequency hopping, and is a transmission method in which data transmission is performed multiple times in each frequency channel that is switched by frequency hopping.
With such a transmission method, the same actions and effects as those of the transmission device according to the above embodiment can be obtained.

In addition, a receiving device (receiver 20) as an embodiment is a receiving device that receives data transmitted by a transmitting device using a frequency hopping method, and is equipped with a receiving unit (same 22) that receives data, and a receiving control unit (same 23) that controls the receiving unit to receive each of the data transmitted multiple times by the transmitting device on each frequency channel switched by frequency hopping (see Figures 1, 9, 11, etc.).
This increases the amount of data received per frequency channel.
Therefore, when data communication is performed by the frequency hopping method, the data transfer rate can be improved.

100, 100A Communication system 1, 1A Transmitter 2 Controlled object 11 Operation unit 12 Encoder 13, 13A Transmission control unit 14 Memory unit 15 Transmitter 16, 21 Antenna Is Transmission slot pattern group information SL Slot 18 Receiving unit 20 Receiver 22 Receiving unit 23 Receiving control unit 24 Memory unit 25 Decoder 26 Actuator

Claims (7)

A transmitting device that transmits data by a frequency hopping method,
A transmission unit that transmits data;
A transmission control unit that controls the transmission unit to transmit data multiple times in each frequency channel that is switched by frequency hopping ,
A frequency switching cycle is constant, and the number of data transmissions and the data transmission time length per data transmission are the same in each of the frequency channels;
The number of data transmissions for each frequency channel is c, the data transmission time length is t, and the length of a repeat transmission period, which is a period formed by dividing one frequency period, which is a period between switching timings of the frequency channel, into c equal parts, is f.
The transmission control unit causes a slot for transmitting data to differ among f/t slots formed by equally dividing the repetitive transmission period into f/t slots during at least a part of the repetitive transmission period, thereby causing a data transmission interval to differ.
Transmitting device. a storage unit for storing transmission slot pattern group information, which is information including a plurality of types of transmission slot pattern information having different allocation patterns of the transmission slots to the repetitive transmission period, as transmission slot pattern information, which is information that determines, for each repetitive transmission period, the transmission slots that are the slots for transmitting data among the f/t slots;
The transmitting device according to claim 1 , wherein the transmission control unit causes the transmitting unit to execute data transmission for each of the repetitive transmission periods in accordance with one of the transmission slot pattern information selected from the transmission slot pattern group information. The transmitting device according to claim 2 , wherein the transmission control unit transmits, as the transmission data for each repetitive transmission period, transmission data including a pattern identifier indicating the transmission slot pattern information being selected and information indicating the number of times data is transmitted. A receiving unit for receiving data is provided,
4. The transmitting device according to claim 3, wherein the transmission control unit, before starting data transmission to the receiving device, causes the receiving unit to execute a receiving operation of transmission data of another transmitting device, and determines whether or not the transmission slot pattern information being selected by the other transmitting device matches the transmission slot pattern information that was to be applied by the own device based on the pattern identifier included in the transmission data of the other transmitting device, and when it is determined that the two match, selects another transmission slot pattern information from the transmission slot pattern group information. The transmitting device according to claim 1 , wherein the transmission control unit randomly varies a data transmission interval for a plurality of data transmissions performed for each of the frequency channels. A transmission method in a transmission device that transmits data by a frequency hopping method, comprising:
A data transmission is performed multiple times in each frequency channel switched by frequency hopping ,
A frequency switching cycle is constant, and the number of data transmissions and the data transmission time length per data transmission are the same in each of the frequency channels;
The number of data transmissions for each frequency channel is c, the data transmission time length is t, and the length of a repeat transmission period, which is a period formed by dividing one frequency period, which is a period between switching timings of the frequency channel, into c equal parts, is f.
Among f/t slots formed by equally dividing the repetitive transmission period into f/t slots, the slot in which data is transmitted is made different during at least a part of the repetitive transmission period, thereby making the data transmission interval different.
Transmission method. A receiving device for receiving data transmitted by a transmitting device using a frequency hopping method,
A receiving unit that receives data;
A reception control unit that controls the receiving unit so as to receive data transmitted by the transmitting device a plurality of times in each frequency channel that is switched by frequency hopping ,
A frequency switching cycle is constant, and the number of data transmissions and the data transmission time length per data transmission are the same in each of the frequency channels;
The number of data transmissions for each frequency channel is c, the data transmission time length is t, and the length of a repeat transmission period, which is a period formed by dividing one frequency period, which is a period between switching timings of the frequency channel, into c equal parts, is f.
The reception control unit
The transmitting device controls the receiving unit to receive data transmitted at different data transmission intervals by varying slots for transmitting data among f/t slots formed by equally dividing the repetitive transmission period into f/t slots during at least a portion of the repetitive transmission period.
Receiving device.

Images