COMMUNICATION CONTROL DEVICE, COMMUNICATION CONTROL METHOD, AND DATA COLLECTION SYSTEM

Abstract

To provide a communication control device, a communication control method, and a data collection system that can shift transmission timing from that of other terminal devices.SOLUTION: A communication control device performs calculations using division values obtained by dividing the MAC address assigned to each device, and sets transmission timing on the basis of the calculation result.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a communication control device, a communication control method, and a data collection system. [Background technology]

[0002] There is known a system that collects sensing data measured by sensors of a plurality of terminal devices from the terminal devices. Such systems are used, for example, in smart grids, building lighting management, infrastructure monitoring, crime prevention systems, elderly care services, smart agriculture, etc. In particular, wireless communication using the sub-gigahertz frequency band (for example, a band of around 920 MHz) is expected to be used in the above-mentioned systems because of its advantages of radio waves propagating farther than Wi-Fi (registered trademark) and BLE (Bluetooth Low Energy), being less susceptible to obstacles, and having less radio wave interference.

[0003] In the above-mentioned system, it is required to avoid collision of transmitted data by shifting the transmission timing of each terminal device when collecting sensing data. For example, the following Patent Document 1 describes a technology in which multiple sensors determine the delay time until transmitting data based on the MAC (Media Access Control) address assigned to the sensor. Patent Document 1 also describes that the delay time is determined using a random value Rn based on a random number, and that an individual random value Rn is calculated by using all the digits of the MAC address. Patent Document 1 also describes that the random value Rn is calculated from a part of the MAC address, specifically, the lowest 8 bits of the MAC address. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-197925 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, since MAC addresses are usually assigned in consecutive numbers, the lower 8 bits of the MAC address may also be consecutive or close in value. Therefore, as described in Patent Document 1, the delay time based on all digits or a part of the lower digits of the MAC address cannot sufficiently guarantee the randomness of the delay time. In other words, the transmission timing cannot be shifted sufficiently, and there is a risk of collision of transmission data.

[0006] An object of the present invention is to provide a communication control device, a communication control method, and a data collection system that are capable of shifting the transmission timing between different terminal devices to a necessary and sufficient extent. [Means for solving the problem]

[0007] The present invention relates to A communication control device built into a device, Obtained by dividing the MAC address assigned to each device setting a transmission timing based on a result of multiplying the first divided value and the second divided value; Transmitting predetermined sensing data at a set transmission timing; It is a communication control device.

[0008] The present invention relates to A communication control method performed by a communication control device built into a device, comprising: Obtained by dividing the MAC address assigned to each device setting a transmission timing based on a result of multiplying the first divided value and the second divided value; Transmitting predetermined sensing data at a set transmission timing; A communication control method.

[0009] The present invention relates to A plurality of terminal devices; a communication device that receives sensing data transmitted from each of a plurality of terminal devices; having The terminal device has a sensor that acquires sensing data and a communication control device, The communication control device is obtained by dividing the MAC address assigned to each device. Based on the result of multiplying the first divided value and the second divided value, Setting a transmission timing and performing control to transmit the sensing data to the communication device at the set transmission timing; It is a data collection system. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram to which reference is made when a description of the problems to be considered in the present invention is given. [Diagram 2] FIG. 1 is a diagram to which reference is made when a description of the problems to be considered in the present invention is given. [Diagram 3] FIG. 1 is a diagram to which reference is made when a description of the problems to be considered in the present invention is given. [Figure 4] 1 is a block diagram showing a configuration example of a communication control device according to an embodiment; [Diagram 5] 10 is a flowchart showing a flow of processing performed in a communication control device according to an embodiment. [Figure 6] FIG. 13 is a diagram for explaining a modified example. [Figure 7] FIG. 13 is a diagram for explaining a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the embodiments described below are preferred specific examples of the present invention, and the content of the present invention is not limited to these embodiments. The description will be given in the following order. <Issues to be considered in the present invention> <One embodiment> <Modification>

[0012] <Issues to be considered in the present invention> First, in order to facilitate understanding of the present invention, problems to be considered in the present invention will be described. FIG. 1 is a diagram showing an example of the configuration of a data collection system (data collection system 1). The data collection system 1 has, for example, a plurality of terminal devices 2, an aggregator 3 (an example of a communication device) wirelessly connected to the plurality of terminal devices 2, and a cloud computer CP such as a server connected to the aggregator 3. In FIG. 1, seven terminal devices (terminal devices 2A, 2B, 2C, . . . 2G) are shown as the plurality of terminal devices 2. When it is not necessary to distinguish between the individual terminal devices, they are collectively referred to as terminal devices 2. Of course, the number of terminal devices 2 may be other than seven. In the data collection system 1, sensing data measured by a sensor (sensor 5 described later) included in the terminal device 2 is transmitted from the terminal device 2 to the aggregator 3. The aggregator 3 aggregates the sensing data by receiving the sensing data transmitted from each terminal device 2, and then transmits the aggregated sensing data to the cloud computer CP.

[0013] The terminal device 2 has a sensor 5. For example, the terminal device 2A has a sensor 5A, and the terminal device 2B has a sensor 5B. Examples of the sensor 5 include a temperature sensor, a humidity sensor, an acceleration sensor, an environmental sensor that measures wind, temperature, and humidity, and a biological sensor that measures biological information such as body temperature and pulse rate.

[0014] Each terminal device 2 has a communication function for transmitting sensing data obtained by the sensor 5 to the aggregator 3. The terminal device 2 transmits the sensing data to the aggregator 3, for example, by wireless communication using the sub-gigahertz frequency band. The sub-gigahertz frequency band means a frequency band below 1 GHz. The terminal device 2 periodically transmits the sensing data to the aggregator 3 at a predetermined time interval after, for example, the initial transmission after startup.

[0015] The aggregator 3 is, for example, a gateway or an access point, and is a communication device that transmits the sensing data transmitted from the terminal device 2 to the cloud computer CP. The aggregator 3 transmits the sensing data to the cloud computer CP based on a communication standard such as LTE (Long Term Evolution), 4G (Generation) (fourth generation mobile communication system), or 5G (fifth generation mobile communication system).

[0016] The cloud computer CP performs processing using the sensing data transmitted from the aggregator 3. The content of the processing differs depending on the application of the data collection system 1.

[0017] A specific example of the data collection system 1 will be described. The data collection system 1 can be applied to, for example, a street light status determination system. In this example, the terminal device 2 is a street light, and the sensor 5 is an acceleration sensor. Sensing data of the acceleration sensor transmitted from the street light is transmitted to the cloud computer CP via the aggregator 3. The cloud computer CP can detect, for example, that the street light is tilted differently from its normal installation state by monitoring the sensing data of the acceleration sensor. Depending on the detection result, a maintenance worker can be dispatched to the street light, thereby appropriately maintaining and inspecting the street light. Of course, this example is one of the specific examples of the data collection system 1, and the contents of the present invention are not limited to this specific example.

[0018] Between the terminal device 2 and the aggregator 3, wireless communication is performed according to a communication method based on LPWA (Low Power Wide Area). Although the transmission speed of LPWA is slower than that of cellular lines such as 3G lines and 4G lines and wireless LANs (Local Area Networks), it has the characteristics of being able to transmit over a wide range, having a narrow frequency band, and consuming very little power. For this reason, it is suitable for a sensor network that transmits a large amount of small sensing data from multiple locations, such as the data collection system 1.

[0019] Examples of communication standards based on LPWA include, but are not limited to, SIGFOX (sub-GHz band (866 MHz band, 915 MHz band, 920 MHz band) (registered trademark), maximum transmission speed of about 100 bps, transmission distance of about several tens of km), LoRa (sub-GHz band, maximum transmission speed of about 250 kbps, transmission distance of about 10 km) (registered trademark), Wi-Fi HaLow (sub-GHz band, maximum transmission speed of about 150 kbps, transmission distance of about 1 km), Wi-SUN (sub-GHz band, maximum transmission speed of 800 kbps, transmission distance of about 1 km) (registered trademark), and Flexnet (280 MHz band, maximum transmission speed of 10 kbps, maximum transmission distance of about 20 km) (registered trademark).

[0020] Furthermore, since a plurality of terminal devices 2 are arranged in the data collection system 1, it is desirable that the terminal devices 2 not only consume low power, but also are small in size and low in cost.

[0021] Incidentally, the aggregator 3 receives sensing data transmitted from a plurality of terminal devices 2, but cannot receive a plurality of sensing data at the same timing. For example, as shown in FIG. 2, when the aggregator 3 receives sensing data transmitted from the terminal device 2A, the aggregator 3 cannot receive sensing data transmitted from the other terminal devices 2B to 2G. In order to avoid the aggregator 3 being unable to receive the sensing data transmitted from the terminal device 2B, etc., it is necessary to intentionally shift the transmission timing of the sensing data of each terminal device 2 to avoid collision of the transmitted sensing data. In the case where the communication time is very short but the power is turned on at the same time, the possibility of collision of the transmitted data increases, especially when the terminal device 2 is started up. For example, in the case where the terminal device 2 described above is a facility such as a street light, it is assumed that the power is turned on remotely at the same time after the street light is installed. Therefore, it is particularly necessary to shift the initial transmission timing after starting up.

[0022] In order to reliably shift the timing of transmitting sensing data for each terminal device 2, it is possible to generate a random number and delay the transmission timing from a reference time by an amount corresponding to the random number. For example, if the initial transmission timing can be shifted for each terminal device 2, it is possible to avoid overlapping transmission timing even if the sensing data is transmitted at regular intervals thereafter. With this method, each terminal device 2 is configured to receive RN G It is required to have a Random Number Generator (Random Number Generator) function.

[0023] FIG. 3 is a flow chart showing the flow of a process for shifting the transmission timing using a random number. In step ST1, a process for starting up each terminal device 2 is performed. For example, a command is sent simultaneously to each terminal device 2 from a management center or the like, and each terminal device 2 starts up simultaneously based on the command. Each terminal device 2 may have an internal RTC (Real Time Clock), and when the RTC reaches a predetermined time, each terminal device 2 may start up simultaneously. Note that in this example, each terminal device 2 is started up simultaneously, but may also be started up at different times. Then, the process proceeds to step ST2.

[0024] In step ST2, the RN of the terminal device 2 G The process of generating a random number (unique value) is then performed using the function. Then, the process proceeds to step ST3.

[0025] In step ST3, the terminal device 2 determines a delay time based on a random number. Then, the terminal device 2 sets a timing delayed by the delay time from a reference time (for example, a startup timing) as the initial transmission timing of the sensing data. Then, the process proceeds to step ST4.

[0026] In step ST4, an initial transmission process is performed to transmit the sensing data at the transmission timing set in step ST3, and the process then proceeds to step ST5.

[0027] In step ST5, a process of periodically transmitting sensing data is performed at fixed time intervals from the transmission timing set in step ST3. The fixed time interval is common to each terminal device 2, for example, and the specific time differs depending on the communication method. Since the initial transmission timing set in step ST3 is different for each terminal device 2, the possibility of the transmission timings overlapping in the process of periodically transmitting sensing data is reduced.

[0028] According to the method described above, it is possible to avoid overlapping of transmission timing. However, as described above, it is desirable that the terminal device 2 used in the data collection system 1 be as low cost as possible. G Providing this function may increase the cost of the terminal device 2. In addition, for example, in a system in which each terminal device 2 starts up at the same time and then transmits sensing data periodically, it is sufficient to shift the transmission timing at startup for each terminal device 2, and there is little need to strictly shift the transmission timing using random numbers. In addition, there is a risk that the power consumption of the terminal device 2 will increase in order to perform a process of generating random numbers. Taking the above points into consideration, one embodiment of the present invention will be described in detail.

[0029] <One embodiment> [Example of communication control device configuration] 4 is a block diagram showing a configuration example of a communication control device (communication control device 10) according to this embodiment. The communication control device 10 has, for example, an oscillator 11, a communication circuit 12, and a control circuit 13. The communication control device 10 is, for example, an ultra-compact module (for example, a rectangular parallelepiped with a width and length of about 10 mm and a thickness of about several mm) in which these components are densely arranged, and is built into each terminal device 2. The oscillator 11, the communication circuit 12, and the control circuit 13 are mounted on, for example, a printed circuit board. The printed circuit board may be either single-sided or double-sided, and the number of layers may be any number.

[0030] The oscillator 11 is, for example, a TCXO (Temperature Compensated Crystal Oscillator) that has a built-in temperature sensor and a temperature compensation circuit to reduce changes in frequency due to changes in ambient temperature. The oscillation frequency output by the oscillator 11 is input to the communication circuit 12. The oscillator 11 may be, for example, a simple packaged crystal oscillator (SPXO) that integrates a crystal resonator (not shown) and an oscillation circuit (not shown).

[0031] The communication circuit 12 is a circuit that performs wireless communication corresponding to a communication method using a sub-gigahertz frequency band. The communication circuit 12 is configured with a communication IC (Integrated Circuit) such as an RFIC (Radio Frequency Integrated Circuit). The communication circuit 12 communicates with the aggregator 3 and the like via an antenna AT. The antenna AT may be a built-in antenna that is accommodated in the housing of the communication control device 10.

[0032] Specifically, the communication circuit 12 has a first communication circuit 12A and a second communication circuit 12B. The first communication circuit 12A performs a transmission process of transmitting data (e.g., sensing data) using the oscillation frequency output from the oscillator 11 as a process using the oscillation frequency. The first communication circuit 12A is composed of, for example, a filter, a modulation circuit, etc., and modulates the oscillation frequency from the oscillator 11 according to the transmission data, outputs the modulated signal (RF signal) to the antenna AT, and performs data transmission.

[0033] The second communication circuit 12B performs reception processing. The second communication circuit 12B is composed of, for example, a filter and a demodulation circuit, and receives an RF signal transmitted from a base station or the like via an antenna AT, and demodulates the received RF signal to obtain reception data. The reception data is output to, for example, the control circuit 13 for use.

[0034] The control circuit 13 is configured, for example, by a microcomputer (MCU: Micro Controller Unit) (sometimes abbreviated as a microcomputer), and controls the components constituting the communication control device 10, such as the oscillator 11 and the communication circuit 12. The control circuit 13 transmits and receives data to and from an external module (for example, a higher-level control microcomputer) via an external interface. An example of this external interface is a universal asynchronous receiver / transmitter (UART). The external interface may be another interface. The higher-level control microcomputer is connected to a sensor 5 included in the terminal device 2. The higher-level control microcomputer appropriately converts sensing data measured by the sensor 5 into digital data and supplies the data to the control circuit 13. The control circuit 13 transmits the sensing data supplied from the higher-level control microcomputer to the aggregator 3 via the communication circuit 12.

[0035] Furthermore, the control circuit 13 generates a transmission timing delayed by the delay time from the reference time, and sets the timing in an appropriate memory. In this embodiment, the reference time is described as being at startup (specifically, when the power is turned on), but it may be at a time other than startup (for example, when transitioning from a sleep state to an active state). Then, when the current time becomes the set transmission timing, the control circuit 13 controls the communication circuit 12 to transmit the sensing data to the aggregator 3. A specific example of generating the transmission timing will be described later.

[0036] [Example of communication control device operation] Next, an example of the operation of the communication control device 10 will be described with reference to the flowchart of Fig. 5. In step ST11, the control circuit 13 performs processing to start each unit of the communication control device 10 in response to the start of the terminal device 2. In this example, the terminal devices 2 constituting the data collection system 1 start simultaneously in response to remote control of each terminal device 2. Of course, each terminal device 2 may start simultaneously by performing autonomous control. Then, the processing proceeds to step ST12.

[0037] In step ST12, the control circuit 13 performs a process of generating a random value. Then, the process proceeds to step ST13.

[0038] In step ST13, the control circuit 13 obtains a delay time based on the random value generated in step ST12. Then, the control circuit 13 sets a timing delayed by the delay time from a reference time (for example, a start-up timing) as the initial transmission timing of the sensing data. Then, the process proceeds to step ST14.

[0039] In step ST14, the control circuit 13 controls the communication circuit 12 to transmit the sensing data to the aggregator 3 at the transmission timing set in step ST13. The transmission process here is the initial transmission process. Then, the process proceeds to step ST15.

[0040] In step ST15, a process of periodically transmitting sensing data is performed at fixed time intervals from the transmission timing set in step ST13. The fixed time interval is common to each terminal device 2, and the specific time differs depending on the communication method. Since the transmission timing set in step ST13 differs for each terminal device 2, the possibility of the transmission timings overlapping in the process of periodically transmitting sensing data is reduced.

[0041] [Transmission timing setting process] Next, a specific example of the process for setting the transmission timing performed in the above-mentioned step ST13 will be described. For example, the control circuit 13 performs a calculation using a divided value obtained by dividing the MAC address assigned to each device, and sets the transmission timing based on the calculation result.

[0042] In this example, the MAC address will be described using an IEEE (Institute of Electrical and Electronics Engineers) address (extended 64 bits), but is not limited to this. Of the 64-bit MAC address, the upper 24 bits are a vendor identifier called an OUI (Organizationally Unique Identifier), and the lower 40 bits are a number assigned by the vendor. The MAC address is stored in an appropriate memory of the terminal device 2.

[0043] (First example) The control circuit 13 reads the 64-bit MAC address from the memory and divides it into upper 32 bits (an example of a first divided value) and lower 32 bits (an example of a second divided value).Then, the control circuit 13 performs an operation of multiplying the upper 32 bits by the lower 32 bits, and sets the transmission timing based on the operation result.

[0044] A specific example will be given for explanation. For example, the MAC address of terminal device 2A is 00019003000170F1 Let us assume that. The control circuit 13 divides the MAC address into upper 32 bits and lower 32 bits, and multiplies these together using the following formula (1) to obtain a pseudo-random value. (0x00019003 × 0x000170F1) ···Formula (1) Furthermore, in order to keep the calculation result (pseudo-random value) of equation (1) below a certain value (to prevent the delay from the reference time from becoming too large), the control circuit 13 performs an operation to remove & with "0x1FFF", an example of a mask value, as in equation (2) below, to obtain a random value. (0x00019003 × 0x000170F1) & 0x1FFFF ···Formula (2) The result of the calculation of formula (2) is a random value 0x192D3(103,123) (The numbers in parentheses are in decimal notation.) Here, if you convert the random value into a unit of time of 100 μs, you get a delay time of 10.3 s. The control circuit 13 sets the timing delayed by the obtained time (10.3 s) from the start-up of the terminal device 2A as the initial transmission timing of the sensing data.

[0045] The MAC address of another terminal device (for example, terminal device 2B) 00019003000170F2 Let us assume that. The control circuit 13 divides the MAC address into upper 32 bits and lower 32 bits, and multiplies these together using the following formula (3) to obtain a pseudo-random value. (0x00019003 × 0x000170F2) ···Formula (3) Furthermore, in order to make the calculation result of equation (3) equal to or less than a certain value, the control circuit 13 performs an operation to remove & from "0x1FFF", which is an example of a mask value, as in equation (4) below, to obtain a random value. (0x00019003 × 0x000170F2) & 0x1FFFF ···Formula (4) The result of the calculation of formula (4) is a random value 0x122D6 (74,454) (The numbers in parentheses are in decimal notation.) Here, similarly to the case of the terminal device 2A, if the random value is converted with 100 μs as one unit of time, a delay time of 7.4 s is obtained. The control circuit 13 sets the timing delayed by the obtained time (7.4 s) from the start-up of the terminal device 2B as the initial transmission timing of the sensing data.

[0046] As shown in the first example above, there is a high possibility that the MAC addresses assigned to each terminal device 2 constituting the data collection system 1 are consecutive numbers. For this reason, if the entire MAC address or a part of the lower bits, etc., is used as is, the delay time will be approximately the same value, and the transmission timing cannot be shifted sufficiently. However, in this example, by performing an operation to multiply the upper 32 bits and the lower 32 bits of the MAC address, it is possible to shift the transmission timing sufficiently even if the MAC address is a consecutive number. In addition, terminal device 2 is RN G Since there is no need for the function, even a low-spec IC can be used as the communication control device 10.

[0047] In the above example, the 64 bits are halved, but the present invention is not limited to this. For example, the upper 24 bits (e.g., OUI) and the lower 40 bits (MAC address assigned by the manufacturer) may be divided, and the two may be multiplied together. In addition, all of the 64 bits do not have to be used. For example, the upper 8 bits and the lower 20 bits may be divided, and the two may be multiplied together. In addition, the MAC address may be divided into three or more parts instead of two parts, and all or some of the parts may be multiplied together. In addition, when multiple MAC addresses are assigned to one terminal device 2, a divided value obtained by dividing one MAC address may be multiplied by a divided value obtained by dividing the other MAC address. Examples of multiple (e.g., two) MAC addresses assigned to one terminal device 2 include a MAC address assigned to a communication control device (or a control circuit) by an IC vendor at the time of shipment, and a MAC address numbered and assigned by a manufacturer when a product using the communication control device (or a communication control device using a control circuit) is shipped as the manufacturer's product.

[0048] (Second example) The second example is an example in which the transmission timing is set based on the result of a calculation in which a divided value obtained by dividing a MAC address assigned to each device is multiplied by a unique value different from the MAC address. The unique value different from the MAC address is, for example, a serial number assigned to the communication control device 10. In this example, the lower 32 bits obtained by dividing the MAC address are used as the divided value. Of course, the divided value may be something other than the lower 32 bits of the MAC address.

[0049] A specific example will be given for explanation. For example, the serial number of the terminal device 2A is G723538 and the MAC address is 00019003000170F1 Let us assume that. The control circuit 13 obtains a pseudo-random value by performing the calculation of the following equation (5), which multiplies the serial number by the lowest 32 bits. (723538 × 0x000170F1) ···Formula (5) Furthermore, in order to make the calculation result of equation (5) equal to or less than a certain value, the control circuit 13 performs an operation to remove & from "0x1FFF", which is an example of a mask value, as in equation (6) below, to obtain a random value. (723538 × 0x000170F1) & 0x1FFFF ···Formula (6) The result of the calculation of formula (6) is a random value 0x9732 (38,706) (The numbers in parentheses are in decimal notation.) Here, if you convert the random value with 100 μs as one unit of time, you get a delay time of 3.8 s. The control circuit 13 sets the timing delayed by the obtained time (3.8 s) from the start-up of the terminal device 2A as the initial transmission timing of the sensing data.

[0050] The serial number of another terminal device (for example, terminal device 2B) G926040 and the MAC address is 00019003000170F2 Let us assume that. The control circuit 13 obtains a pseudo-random value by performing the calculation of the following equation (7), which multiplies the serial number by the lowest 32 bits. (92640 × 0x000170F2) ···Formula (7) Furthermore, in order to make the calculation result of equation (7) equal to or smaller than a certain value, the control circuit 13 performs an operation to remove & from "0x1FFF", which is an example of a mask value, as in equation (8) below, to obtain a random value. (92640 × 0x000170F2) & 0x1FFFF ···Formula (8) The result of the calculation of formula (8) is a random value 0x530 (1,328) (The numbers in parentheses are in decimal notation.) Here, if you convert the random value into a unit of time of 100 μs, you get a delay time of 0.1 s. The control circuit 13 sets the timing delayed by the obtained time (0.1 s) from the start-up of the terminal device 2B as the initial transmission timing of the sensing data. The second example shown above also provides the same effects as the first example described above.

[0051] [About mask values] Next, we will explain the mask value used in the above calculation. The 920MHz band communication is different depending on the purpose and protocol used. Communication time per transmission - Interval for each communication (maximum delay value based on the interval (maximum delay time)) Therefore, in this embodiment, the mask value is determined based on one transmission time, one unit time, an interval for each communication, and a maximum delay time for the interval in the communication protocol.

[0052] (First example) In the first example, the case where the communication protocol is SIGFOX (registered trademark) will be explained. SIGFOX (registered trademark) is a low-spec, simple communication standard specialized for sensor networks. The main communication specifications of SIGFOX (registered trademark) are: Communication time per transmission: Approximately 6 seconds (transmitted 3 times (approximately 2 seconds each) with frequency hopping) - Communication interval: once every 10 minutes at the shortest (SIGFOX (registered trademark) has a maximum of 140 transmissions per day under the contract)

[0053] Here, assuming that one transmission is always made within 30% of the communication interval, The maximum delay time is 3 minutes (10 minutes x 0.3) It becomes. If the communication time for one transmission is taken as one unit of time, then Time per unit: 2 seconds (6 seconds ÷ 3 times) It becomes. In this case, the setting range of the random value (value before conversion to 1 unit time) is: 180 seconds (maximum delay time) ÷ 2 seconds (time per unit) = 90 That is, a random value is set in the range of 0 to 90. That is, a 7-bit mask value is used to keep the random value within that range. In the case of SIGFOX (registered trademark), one transmission is long, so one unit time is long and the upper limit of the random value is set low. In SIGFOX (registered trademark), three communications are performed with frequency hopping, so there is a high possibility that collisions of transmission data can be avoided even if the random values ​​overlap. Therefore, collisions of transmission data can be avoided even if the random value is set low.

[0054] (Second example) This is an example of a case where a unique communication protocol that is not standardized is used. The communication protocol is Communication speed: 100bps Carrier sense: None / duty within 1% (Carrier sense is a mechanism for avoiding interference by detecting (sensing) the carrier before starting transmission, and not transmitting on the same frequency if another terminal device is using the same channel. Duty time means the total amount of time that radio waves can be transmitted. It is usually specified as the maximum amount of time that radio waves can be transmitted per hour. In other words, a duty time of 1% means that the total transmission time is 36 seconds / hour (less than 36 seconds (3600 seconds x 0.01) per hour).) Communication time per transmission: Approximately 20 ms Interval: Once every 5 minutes Maximum delay time: 30 seconds (assuming one transmission within 10% of the interval) Time per unit: 20 ms (in this example, equal to the communication time per transmission) In this case, the range of random values ​​is: 30000ms (maximum delay time) ÷ 20ms (time per unit) = 1500 That is, a random value is set in the range of 0 to 1500. An 11-bit mask value is used to keep the random value within that range. Since the communication time per transmission is short, the setting range of the random value is expanded to some extent in order to reliably avoid collisions of transmitted data.

[0055] (Third example) This example is an example of a case where a unique communication protocol that is not standardized is used. The difference from the second example is that carrier sense is performed. Time per unit: 1 ms (In this example, the minimum shift range is set to avoid simultaneous transmission timing, assuming that simultaneous transmission timing collisions can be avoided by carrier sense. In other words, the time per unit is set to a value smaller than the communication time per transmission (about 20 ms).) In this case, the setting range of the random value (value before conversion to 1 unit time) is: 30000ms (maximum delay time) ÷ 1ms (time per unit) = 30000 That is, a random value is set in the range of 0 to 30,000. A 15-bit mask value is used to keep the random value within that range. By setting a time per unit that is even shorter than the second example described above, the range of the random value can be expanded. For example, when many terminal devices 2 (sensors 5) are installed in the data collection system 1, by setting the time per unit, the range of the random value can be expanded, and it is possible to effectively suppress the transmission timings from overlapping.

[0056] Summarizing the first to third examples described above, it is as follows. · One transmission time = a · Time per unit = b · Interval for each communication = c · Maximum delay time = d (always transmit within x% of c, where d = c * x%) Use the above as parameters.

[0057] <Condition 1; when a ≤ b> Let n be the upper limit value of natural numbers of 2 or more that satisfy "b × n ≤ d". (n; the upper limit value of the number of times of one transmission communicated within the interval)

[0058] <Condition 2; for a system without carrier sense when b m is a natural number of 2 or more that satisfies "a ≤ b × m", and (m; the value to multiply in order to use a time of one transmission time or more as a repeated unit time) Let n be the upper limit value of natural numbers of 2 or more that satisfy "(b × m) × n ≤ d".

[0059] <Condition 3; for a system with carrier sense when b Let n be the upper limit value of natural numbers of 2 or more that satisfy "b × n ≤ d". (n; the upper limit value of the number of times of one transmission communicated within the interval) Even if the delay time differs only within a range of one transmission time, direct collision of transmission data can be avoided by performing carrier sensing.

[0060] In the above conditions 1, 2 and 3, The "pseudo-random value" is masked so that the random value used is the same number of digits as the binary representation of n, starting from the least significant bit, to obtain a random value.

[0061] [Effects obtained by this embodiment] According to the present embodiment described above, the following effects can be obtained. This makes it possible to reliably shift the transmission timing between different terminal devices, thereby preventing collisions of transmission data. Also, in a system in which each terminal device starts up at the same time, the timing of the first transmission after startup can be reliably shifted. Therefore, when transmitting sensing data at regular intervals after the first transmission, it becomes possible to reliably shift not only the timing of the first transmission but also the timing of subsequent transmissions. RN G Since this function is unnecessary, the communication control device can be configured using inexpensive ICs, reducing the cost of the communication control device and the power consumption of the communication control device. In addition, the optimal mask value can be set according to the communication protocol and system configuration, taking into account the relationship between one transmission time, one unit time, the interval between communications, and the maximum delay time, making it possible to set the optimal transmission timing.

[0062] <Modification> Although the embodiment of the present invention has been specifically described above, the present invention is not limited to the above-described embodiment, and various modifications based on the technical concept of the present invention are possible.

[0063] [Variation 1] As shown in FIG. 6, the communication control device 10 may be configured to include a host control microcomputer (host control microcomputer 40) connected to the control circuit 13 and a sensor 41 connected to the host control microcomputer 40. The sensor 41 may be one sensor or may include a plurality of sensors. The host control microcomputer 40 supplies sensing data detected by the sensor 41 to the control circuit 13. The control circuit 13 controls the communication circuit 12 to transmit the sensing data received from the host control microcomputer 40 to the aggregator 3. In the configuration shown in FIG. 6, the host control microcomputer 40 may obtain a transmission timing by performing the calculation described in the embodiment, and set the transmission timing to the control circuit 13. Then, the control circuit 13 may transmit the sensing data received from the host control microcomputer 40 to the aggregator 3 at the set transmission timing. According to this modification, the host control microcomputer 40 performs the calculation, so that the processing can be speeded up.

[0064] 6, some of the series of calculations may be performed by the host control microcomputer 40, and the remaining calculations may be performed by the control circuit 13. For example, the host control microcomputer 40 may perform calculations up to multiplication by a mask value, and the control circuit 13 may calculate the delay time by converting the calculation results into time per unit. Alternatively, the host control microcomputer 40 may perform calculations to calculate a mask value, and the control circuit 13 may perform calculations using the mask value, and calculate the delay time based on the calculation results.

[0065] [Variation 2] As shown in FIG. 7, there may be no higher-level control microcomputer, and the control circuit 13 may be connected to a sensor (sensor 42). The sensor 42 may be a single sensor, or may include multiple sensors. In the configuration shown in FIG. 7, the control circuit 13 directly controls the sensor 42. That is, the control circuit 13 transmits the sensing data received from the sensor 42 to the aggregator 3 at a transmission timing set by the control circuit 13 itself. According to this modification, since there is no higher-level control microcomputer, the communication control device 10 can be made smaller and costs can be reduced.

[0066] [Other variations] In the embodiment described above, each terminal device performs the calculation, but it is also possible that instead of all terminal devices, one or more specific terminal devices 2 obtain the divided values ​​and serial numbers and then perform the calculation. Then, the transmission timing based on the calculation result may be set for the corresponding terminal device.

[0067] The configuration, method, process, shape, material, and numerical values ​​of the above-mentioned embodiment can be combined or substituted with each other without departing from the spirit of the present invention. Also, one thing can be divided into two or more things, and two or more things can be combined into one thing. Furthermore, some things can be omitted.

[0068] Furthermore, the communication control device according to one embodiment or a modified example may be used as a component of electronic devices such as computers, imaging devices, clocks, display devices, and medical equipment, mobile objects such as vehicles, aircraft, and ships, and base stations. [Explanation of symbols]

[0069] 1. Data Acquisition System 2. Terminal device 5, 41, 42... Sensor 10. Communication control device 12. Communication circuit 13. Control circuit 40.... Upper control microcomputer

Claims

1. A communication control device incorporated in a device, setting a transmission timing based on a result of multiplying a first division value and a second division value obtained by dividing a MAC address assigned to each of the devices; Transmitting predetermined sensing data at the set transmission timing. Communications control device.

2. and setting the transmission timing based on a result of multiplying the result of the calculation by a predetermined mask value that makes the result of the calculation equal to or smaller than a certain value. The communication control device according to claim 1 .

3. A delay time is calculated by converting the calculation result multiplied by the mask value into a unit time, and a timing delayed by the delay time from a reference time is set as the transmission timing. The communication control device according to claim 2.

4. The mask value is determined based on one transmission time, one unit time, an interval for each communication, and a maximum delay time for the interval. The communication control device according to claim 2.

5. performing control to transmit the predetermined sensing data at the set transmission timing; 5. A communication control device according to claim 1.

6. Transmitting the predetermined sensing data by wireless communication using a sub-gigahertz frequency band; 5. A communication control device according to claim 1.

7. A communication control method performed by a communication control device built into a device, comprising: setting a transmission timing based on a result of multiplying a first division value and a second division value obtained by dividing a MAC address assigned to each of the devices; Transmitting predetermined sensing data at the set transmission timing. Communications control method.

8. A plurality of terminal devices; a communication device that receives the sensing data transmitted from each of the plurality of terminal devices; having The terminal device includes a sensor that acquires the sensing data and a communication control device, the communication control device sets a transmission timing based on a calculation result obtained by multiplying a first division value and a second division value obtained by dividing a MAC address assigned to each device, and performs control to transmit the sensing data to the communication device at the set transmission timing. Data collection system.

9. The plurality of terminal devices are simultaneously started in response to remote operations performed on each of the terminal devices. The data collection system of claim 8.

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