JPWO2020188937A1 - Information processing equipment, data collection system, communication setting method, and program - Google Patents

Abstract

Efficiently realize wireless communication even when multiple data collection systems compete. The information processing device is an information processing device that manages the communication of the first data collection system (1), and is shared by the first data collection system (1) and another data collection system (2). The first data collection system according to the estimation unit (113) that estimates the communication status of the radio channel based on the observation result of communication using the radio channel, and the communication status estimated by the estimation unit (113). It has a setting unit (114) for setting a channel used by the terminal device (13) that wirelessly transmits the data collected in (1).

Description

The present invention relates to an information processing apparatus, a data collection system, a communication setting method, and a program.

In recent years, with the progress of digitalization in various industries, efforts to collect various sensor information such as vibration, temperature, and humidity to improve work efficiency and productivity are increasing. In particular, smart meters for electricity, gas, water, etc. are expected to enable quick failure detection and more efficient operation by collecting more detailed data from sensors in real time. .. The smart meter is expected to utilize LPWA (Low Power Wide Area), which is a wireless communication method having a long communication distance. LPWA is a wireless communication that uses a wireless frequency band (unlicensed band) that can be used without a license. Compared to Wi-Fi, LPWA has the characteristics of slower communication speed, longer communication distance, and lower power consumption. be. As LPWA, for example, LORA, SIGFOX, Wi-SUN and the like are known.

With the widespread use of LPWA-based data collection services (IoT (Internet of Things) data collection systems), competition for the use of radio resources between data collection services is expected. Especially in LPWA where the communication distance is long and the communication speed is slow, the communication capacity that can be used per area is small, which may cause a serious problem.

Therefore, it is considered that control technology for optimizing the use of radio waves and optimizing the quality of data collection services is required. In relation to this, for example, in Non-Patent Document 1, in order to quickly estimate the state of wireless communication, the server measures the arrival rate etc. from the data transmission result from the terminal, and Bayesian estimation is performed using this as an input. It discloses a system for state estimation and decision making.

Konan, Suzuki, Hasegawa, Shimonishi, Murata, "Wireless channel allocation method in LPWA network using cognitive model of brain", Shingaku Giho, vol.118, no.6, pp.7-12, 2018

As mentioned above, conflicts may occur in the use of radio resources in multiple data collection systems.
Therefore, one of the purposes of the present disclosure is an information processing apparatus, a data collection system, a communication setting method, and a program capable of efficiently realizing wireless communication even when a plurality of data collection systems compete with each other. Is to provide.

The information processing device according to the first aspect is an information processing device that manages the communication of the first data collection system.
An estimation means for estimating the communication status of a radio channel shared by the first data collection system and another data collection system based on the observation result of communication using the radio channel, and an estimation means.
It has a setting means for setting a channel used by a terminal device that wirelessly transmits data collected in the first data collection system according to a communication condition estimated by the estimation means.

The data collection system according to the second aspect is
It is provided with an information processing device that manages communication of the data collection system and a terminal device that wirelessly transmits data collected in the data collection system.
The information processing device is
An estimation means that estimates the communication status of a radio channel shared by the data collection system and another data collection system based on the observation results of communication using the radio channel.
It has a setting means for setting a channel used by the terminal device according to a communication condition estimated by the estimation means.

In the communication setting method according to the third aspect,
The communication status of the radio channel shared by the first data collection system and the other data collection system is estimated based on the observation result of the communication using the radio channel.
According to the estimated communication condition, the channel used by the terminal device that wirelessly transmits the data collected in the first data collection system is set.

The program according to the fourth aspect is
For the computer of the information processing device that manages the communication of the data collection system,
An estimation step for estimating the communication status of a radio channel shared between the data collection system and another data collection system based on the observation result of communication using the radio channel, and an estimation step.
According to the communication status estimated in the estimation step, the setting step of setting the channel used by the terminal device that wirelessly transmits the data collected in the data collection system whose communication is managed by the information processing device is executed.

According to the above aspect, it is provided to provide an information processing device, a data collection system, a communication setting method, and a program capable of efficiently realizing wireless communication even when a plurality of data collection systems compete with each other. Can be done.

It is a block diagram which shows an example of the configuration of the network server which concerns on the outline of embodiment. It is a block diagram which shows an example of the structure of the data collection system which concerns on embodiment. It is a table which shows an example of a data rate. It is a block diagram which shows an example of the specific configuration of the network server which concerns on embodiment. It is a block diagram which shows an example of the hardware configuration of the network server which concerns on embodiment. It is a flowchart which shows an example of the operation flow about the setting of a channel in Embodiment 1. FIG. It is a graph which shows an example of the transition of the received signal strength about the transmission of a periodic radio frame by the same terminal device. It is a graph which shows an example of the transition of the diffusion rate about the transmission of a periodic radio frame by the same terminal device. It is a graph which shows an example of the transition of the received signal strength when there is a retransmission.

Prior to the detailed description of the embodiment, the outline of the embodiment will be described.
FIG. 1 is a block diagram showing an example of the configuration of the network server 11 according to the outline of the embodiment. The network server 11 belongs to the data collection system and is a device that manages the communication of the data collection system. This data collection system includes a terminal device that wirelessly transmits the data collected in the data collection system for collection. The network server 11 may be referred to as an information processing device. As shown in FIG. 1, the network server 11 has an estimation unit 113 and a setting unit 114.

The estimation unit 113 estimates the communication status of the radio channel shared by the data collection system to which the network server 11 belongs and another data collection system based on the observation result of the communication using the radio channel.
The setting unit 114 sets the channel used by the terminal device described above according to the communication status estimated by the estimation unit 113.
According to the network server 11 shown in FIG. 1, the communication status of the radio channel shared by the plurality of data collection systems is estimated, and the channel is set according to the estimation result. Therefore, even when a plurality of data collection systems compete with each other, wireless communication can be efficiently realized.

Next, the details of the embodiment will be described.
<Embodiment 1>
FIG. 2 is a block diagram showing an example of the configuration of the data collection system 1 according to the embodiment. As shown in FIG. 2, the data collection system 1 includes an application server 10, a network server 11, a gateway 12, and a terminal device (user node) 13. Note that FIG. 2 also illustrates a data collection system 2 that provides a data collection service different from the data collection service provided by the data collection system 1. The data collection system 2 includes an application server 20, a network server 21, a gateway 22, and a terminal device (user node) 23. In the present embodiment, the data collection systems 1 and 2 are LoRaWAN systems, but the data collection system 1 and 2 are not limited to this, and may be a system that performs communication conforming to other LPWA standards. The data collection systems 1 and 2 are, for example, IoT data collection systems that collect data from many terminals. The number of terminal devices 13 belonging to the data collection system 1 may be at least one, but typically there are many terminal devices 13. Similarly, the number of terminal devices 23 belonging to the data collection system 2 may be at least one, but typically there are many terminal devices 23.

Although one data collection system 2 is shown in FIG. 2, a plurality of data collection systems 2 may exist. That is, there may be a plurality of data collection systems that compete with the data collection system 1.

The data collection system 1 is a system that collects data from the terminal device 13, and the data from the terminal device 13 is transferred to the application server 10 via the gateway 12 and the network server 11. Similarly, the data collection system 2 is a system that collects data from the terminal device 23, and the data from the terminal device 23 is transferred to the application server 20 via the gateway 22 and the network server 21.

The gateways 12 and 22 and the terminal devices 13 and 23 are wirelessly connected, and LPWA communication according to the LoRaWAN standard is performed. The gateway 12, the network server 11, and the application server 10 are connected so as to be able to communicate by wire or wirelessly. Similarly, the gateway 22, the network server 21, and the application server 20 are communicably connected by wire or wirelessly.
Here, the data collection system 1 and the data collection system 2 cause a conflict in the use of radio resources. That is, the data collection system 1 and the data collection system 2 share the same wireless communication band.

The terminal device 13 stores sensor data such as a gas usage amount, an electricity usage amount, or a water level gauge in a wireless frame and transmits the sensor data to the gateway 12. Similarly, the terminal device 23 also stores the sensor data in the wireless frame and transmits the sensor data to the gateway 22. The wireless frame transmitted by the terminal device 23 can be received by the gateway 12 of the data collection system 1 because the wireless area overlaps between the two systems. However, the gateway 12 is not always able to receive the wireless frame of the terminal device 23, and even if it can be received, it is not always possible to read the contents of the wireless frame. The terminal device 13 is under the control of the network server 11 of the data collection system 1, and the terminal device 13 is under the control of the network server 21 of the data collection system 2. As described above, since the terminal device 23 belongs to the data collection system 2 different from the data collection system 1, it is not possible to perform control such as changing the setting of the terminal device 23 from the data collection system 1.

In the terminal device 13, the transmission timing of the wireless frame and the wireless channel used when transmitting the wireless frame are preset by the network server 11. Similarly, in the terminal device 23, the transmission timing of the wireless frame and the wireless channel used when transmitting the wireless frame are preset by the network server 21. For example, the terminal devices 13 and 23 periodically transmit wireless frames at predetermined time intervals.

The gateway 12 receives the wireless frame from the terminal device 13, stores the data stored in the wireless frame in a packet, and transmits the data to the network server 11. Similarly, the gateway 22 receives the wireless frame from the terminal device 23, stores the data stored in the wireless frame in a packet, and transmits the data to the network server 21.
The network server 11 transmits the data stored in the packet received from the gateway 12 to the application server 10. Similarly, the network server 21 transmits the data stored in the packet received from the gateway 22 to the application server 20.
The application servers 10 and 20 receive the data and execute an arbitrary application such as data aggregation processing.

Hereinafter, the data collection system 1 according to the embodiment will be described in more detail. As described above, the gateway 12 can receive not only the wireless frame from the terminal device 13 but also the wireless frame from the terminal device 23. The gateway 12 stores not only the data stored in the wireless frame but also the reception status information related to the wireless frame in a packet and transmits it to the network server 11. The reception status information includes, for example, reception signal strength, signal noise ratio, wireless communication time, network ID, device ID, destination, ACK request, data rate, radio signal diffusion rate, transmission output, transmission time, reception time, and The used radio channel etc. are included.

The wireless communication time refers to the time during which radio waves are used for transmission of wireless frames, and is also referred to as TOA (Time on air). The network ID is an identifier that identifies which data collection system is used for the network, that is, which data collection system the source terminal device belongs to. The device ID is an identifier that identifies the terminal device of the transmission source. The data rate is control information that defines the diffusivity and bandwidth of the radio wave signal. For example, in LoRaWAN, it is defined as shown in FIG. The ACK request is control information for requesting a response to the destination indicating that the destination of the radio frame (packet) has received the radio frame (packet).

The received signal strength, signal-to-noise ratio, radio communication time, reception time, and radio channel used are acquired, for example, by the gateway 12 observing the radio signal. Further, for the network ID, device ID, destination, ACK request, data rate, radio signal diffusion rate, transmission output, and transmission time, for example, the gateway 12 observes (reads) these information stored in the wireless frame. Acquired by.

The network server 11 accumulates the reception status information stored in the packet and analyzes the accumulated reception status information to estimate the communication status of the wireless channel shared by the data collection system 1 and the data collection system 2. do. That is, the network server 11 estimates based on the reception status information which is the observation result of the communication using the wireless channel. Further, the network server 11 is set to control transmission in the terminal device 13 according to the estimated communication condition. The network server 11 controls transmission in the terminal device 13 by transmitting a command indicating the setting content to the terminal device 13.

FIG. 4 is a block diagram showing an example of a specific configuration of the network server 11. As shown in FIG. 4, it has a transmission / reception unit 110, a packet processing unit 111, an estimation unit 113, and a setting unit 114.

The transmission / reception unit 110 performs packet transmission / reception processing with the gateway 12 or the application server 10. In addition to transmitting and receiving data, the transmission / reception unit 110 transmits / receives commands indicating setting contents.

The packet processing unit 111 processes the received packet. For example, the packet processing unit 111 takes out the data stored in the packet received from the gateway 12 for transfer to the application server 10 and outputs the data to the transmission / reception unit 110. Further, the packet processing unit 111 takes out the reception status information stored in the packet and outputs it to the estimation unit 113. Further, the packet processing unit 111 recognizes the command stored in the packet and performs processing according to the command. For example, when a packet accompanied by an ACK request is received, the packet processing unit 111 instructs the transmission / reception unit 110 to respond to the transmission source.

The estimation unit 113 accumulates reception status information and analyzes the reception status information to estimate the wireless communication status. Further, the setting unit 114 makes settings for controlling transmission in the terminal device 13 according to the communication status estimated by the estimation unit 113. The setting determined by the setting unit 114 is transmitted to the terminal device 13 by the transmission / reception unit 110 as a command. The terminal device 13 that has received the command performs the transmission process of the wireless frame according to the setting contents. The specific processing of the estimation unit 113 and the setting unit 114 in this embodiment will be described later.

Next, an example of the hardware configuration of the network server 11 will be described. FIG. 5 is a block diagram showing an example of the hardware configuration of the network server 11. As shown in FIG. 5, the network server 11 includes, for example, a network interface 50, a memory 51, and a processor 52.

The network interface 50 is used to communicate with other devices such as the gateway 12 and the application server 10. The network interface 50 may include, for example, a network interface card (NIC).

The memory 51 is composed of, for example, a combination of a volatile memory and a non-volatile memory. The memory 51 is used to store software (computer program) including one or more instructions executed by the processor 52, data used for various processes of the network server 11, and the like.
The programs described above can be stored and supplied to a computer using various types of non-transitory computer readable media. Non-temporary computer-readable media include various types of tangible storage media. Examples of non-temporary computer-readable media include magnetic recording media (eg, flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (eg, magneto-optical disks), Compact Disc Read Only Memory (CD-ROM), CD- Includes R, CD-R / W, semiconductor memory (eg, mask ROM, Programmable ROM (PROM), Erasable PROM (EPROM), flash ROM, Random Access Memory (RAM)). The program may also be supplied to the computer by various types of temporary computer readable media. Examples of temporary computer-readable media include electrical, optical, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

The processor 52 reads software (computer program) from the memory 51 and executes it to process each component shown in FIG. That is, each process of the transmission / reception unit 110, the packet processing unit 111, the estimation unit 113, and the setting unit 114 may be realized by executing the program. As described above, the network server 11 has a function as a computer. The processor 52 may be, for example, a microprocessor, an MPU (Micro Processor Unit), a CPU (Central Processing Unit), or the like. The processor 52 may include a plurality of processors.

Next, specific processing of the estimation unit 113 and the setting unit 114 in the present embodiment will be described. The estimation unit 113 of the present embodiment estimates the values of the following two indexes in order to estimate the congestion status (communication status) of radio wave usage for each wireless channel. That is, as the first index, the estimation unit 113 totals the transmission rates of the terminal device 13 belonging to the data collection system 1 and the terminal device 23 belonging to another data collection system (all competing data collection systems 2) ( Estimate the total transmission rate). Further, the estimation unit 113 estimates the communication capacity for each wireless channel as the second index.

First, the estimation of the transmission rate (that is, the total transmission amount per unit time) will be described. In order to obtain the transmission rate, in the present embodiment, attention is paid to the loss rate indicating the frequency of occurrence of an event in which the destination gateways 12 and 22 could not receive the transmission due to the interference of radio waves transmitted by the terminal devices 13 and 23. ..
In the present embodiment, it is assumed that the transmission rate of at least one terminal device 13 of the terminal device 13 belonging to the data collection system 1 is known. At this time, the estimation unit 113 estimates the loss rate P from the transmission rate of the terminal device 13 and the reception rate for the transmission of the terminal device 13 by the following equation (1). The reception rate is calculated from the actual reception result of the gateway 12 for the transmission of the terminal device 13 whose transmission rate is known. That is, the reception rate is obtained by the estimation unit 113 analyzing the reception status information about the wireless frame transmitted from the terminal device 13. In the formula (1), RXRate indicates a known transmission rate, and TXRate indicates a reception rate obtained as an actual observation result.

Further, in the present embodiment, the service rate model of the ALOHA communication method, which is the communication method used in the IoT data collection system, is used. According to this model, it is assumed that the following relational expression (2) holds in this embodiment. In the formula (2), TXRate indicates the total transmission rate of the terminal devices 13 and 23, and RXRate indicates the total communication rate (reception rate) of the wireless communication arriving at the receiving side.

Here, the loss rate P is expressed as 1- (arrival rate). The arrival rate is expressed as the ratio of the reception rate to the transmission rate. Therefore, according to the above equation (2), the following equation (3) holds for the loss rate P.

Therefore, the total TXRate of the transmission rates of the terminal devices 13 and 23 is expressed as a function of P shown in the following equation (4).

Here, if the loss rate in the channel i of interest and P _i, total TXRATE _i of the transmission rate of the terminal device 13, 23 in the channel i is represented by the following equation (5). Note that _Pi is calculated by observing the reception rate for transmission using channel i by the terminal device 13 whose transmission rate is known, as shown in the above equation (1).

As described above, in the present embodiment, the transmission rate is estimated as follows after assuming the characteristic communication method used in the IoT data collection system at the time of estimation. That is, the estimating unit 113 first estimates a packet loss rate P _i in the channel i from a portion of the communication observed by the local system (data collection system 1). _{Then, the estimation unit 113 estimates the transmission rate TX Rate i,} which is the sum of the transmission rate of the terminal device 13 of the own system and the transmission rate of the terminal device 23 of the other system, using the equation (5). In this way, the estimation unit 113 estimates the packet loss rate in the radio channel, and estimates the total transmission rate in the radio channel based on the packet loss rate.

Next, the estimation of the communication capacity for each wireless channel will be specifically described.
As described above, the gateway 12 monitors the radio wave quality of the radio channel, and when the radio frame is transferred to the network server 11, the gateway 12 notifies the network server 11 of the reception status information including the signal-to-noise ratio (SNR).
Estimation unit 113, the effective channel capacity Capacity _i of interest to radio channel i, using the approximation of the theorem of Shannon Hartley, estimated by the following equation (6).

In equation (6), SNR _i represents the observation result of the signal noise ratio of channel i, SNRrange represents the measurable range of the signal noise ratio, and SNRlow represents the lower limit of SNRrange. In this way, the estimation unit 113 estimates the effective communication capacity for each radio channel from the signal noise ratio observed for each radio channel.

In the present embodiment, the setting unit 114 sets the channel i when the estimated transmission rate TXRate _i is equal to or less than a predetermined first threshold value, or when the communication capacity Capacity _i is equal to or less than a predetermined second threshold value. The terminal device 13 housed in i is transferred to another channel. At that time, the setting unit 114 calculates the number of terminal devices 13 to be accommodated in each channel in order to determine which channel should be transferred. That is, the setting unit 114 calculates the maximum number of terminals 13 that can be accommodated in each channel. Hereinafter, a method of calculating the number of terminal devices 13 to be accommodated by each channel, that is, a method of calculating the maximum number of terminal devices 13 to be accommodated in each channel will be described.

The setting unit 114 uses the estimated transmission rate TXRate _i and the communication capacity Capacity _i of each channel to determine the maximum number of terminals 13 that can be accommodated in each channel. _{Specifically, the setting unit 114 calculates the maximum capacity n i} of the terminal device 13 of the channel i by the following equation (7).

In equation (7), N is the total number of terminal devices 13. That is, N is the total number of terminal devices belonging to the data collection system 1, in other words, the total number of terminal devices under the control of the network server 11. m is the number of available channels. γ is a correction parameter (the reciprocal of the number of users that can be accommodated as a whole), and is specifically expressed by the following equation (8).

In the formulas (7) and (8), _Wi is represented by the following formula (9). In other words, _{W i} is, congestion degree of channel i (ie, TXRate _i / Capacity _i) is the reciprocal of.

It is preferable to limit _{n i} so that the utilization rate of each channel does not exceed 1. Therefore, _{it is preferable that n i} satisfies the following equation (10), that is, the relational expression of equation (11). That is, _{it is preferable that n i} is limited to less than T / A.

In equation (10), Link_util _i represents the utilization rate of channel i. TOA _i represents the time (Time on air) when radio waves are transmitted on channel i per unit measurement time. The gateway 12 periodically notifies the network server 11 of _{TOA i as reception status information.} Further, in the equations (10) and (11), T represents a unit measurement time, and A represents an average transmission time required to transmit one radio frame.

Next, the operation flow for setting the channel used by the terminal device 13 will be described. FIG. 6 is a flowchart showing an example of an operation flow for setting a channel in the present embodiment. Hereinafter, the flow of operation will be described with reference to FIG.

In step S100, the terminal device 13 having a known transmission rate transmits a wireless frame using the channel i.

Next, in step S101, the gateway 12 receives _{the radio frame and transfers the reception status information including the signal noise ratio and TOA i} to the network server 11 together with the data stored in the radio frame.

Next, in step S102, the estimation unit 113 of the network server 11 calculates the reception rate for the transmission of the terminal device 13 based on the reception status information acquired in step S101. Then, the estimation unit 113 calculates the loss rate of the channel i according to the equation (1) using this reception rate and the known transmission rate. As described above, in the present embodiment, the estimation unit 113 is based on the known transmission rate of the terminal device 13 that transmits the data collected in the data collection system 1 and the reception rate observed for the terminal device 13. Estimate the packet loss rate.

Next, in step S103, the estimation unit 113 of the network server 11 estimates the transmission rate from the loss rate calculated in step S102 according to the equation (5).

Next, in step S104, the estimation unit 113 of the network server 11 estimates the communication capacity of the channel i according to the equation (6) using the reception status information acquired in step S101.

Next, in step S105, the setting unit 114 determines whether or not the transmission rate estimated in step S103 or the communication capacity estimated in step S104 is equal to or less than the threshold value for the channel i. If any of them is equal to or less than the threshold value, the process proceeds to step S106. If all of them exceed the threshold value, the change of the channel setting is omitted. In the example shown in FIG. 6, the condition for shifting to step S106 is that the transmission rate or the communication capacity is equal to or less than the threshold value, but the condition is that both the transmission rate and the communication capacity are equal to or less than the threshold value. good.

Next, in step S106, the setting unit 114 calculates the maximum number of terminals 13 of each channel to be accommodated according to the equation (7). That is, the setting unit 114 accommodates the number of terminal devices in the wireless channel based on the total number of terminal devices 13, the number of available wireless channels, the estimated total transmission rate, and the estimated communication capacity. To decide.

Next, in step S107, the setting unit 114 transfers a part or all of the terminal device 13 currently accommodated in the channel i to another channel. At this time, the setting unit 114 transfers to the channel in which the number of terminal devices 13 currently accommodated is less than the maximum accommodating number. More preferably, the setting unit 114 transfers to a channel in which the number of terminal devices 13 currently accommodated is less than the maximum accommodating number and the transmission rate and communication capacity exceed the threshold value. The setting unit 114 notifies the new channel by transmitting a command to the terminal device 13 to be transferred. As a result, the terminal device 13 to be transferred will transmit the data on the newly allocated channel at the next data transmission. In this way, the setting unit 114 sets the channel used by the terminal device 13.

The first embodiment has been described above. In this embodiment, the transmission rate and capacity of each channel are estimated using the loss rate and the signal-to-noise ratio generated by the operation of another data collection system 2 that shares radio wave resources. Then, based on these estimation results, the network server 11 determines the channel to be used in the next transmission of the terminal device 13, and notifies the terminal device 13 of this. Upon receiving the notification, the terminal device 13 transmits data using the newly designated channel. This makes it possible to appropriately control the system to be managed without directly using the communication amount and communication content of the data collection system 2. As described above, according to the present embodiment, wireless communication can be efficiently realized even when a plurality of data collection systems compete with each other.

In the above-described embodiment, the estimation unit 113 estimates the transmission rate and the communication capacity according to the above-mentioned mathematical formulas. However, in these estimations, the Bayesian estimation and the Bayesian attractor model are used to improve the estimation accuracy. However, the amount of calculation may be reduced. Bayesian inference has the characteristic that it can be estimated with a small amount of information. In addition, even if a probability distribution of a combination of multiple states such as transmission rate and capacity is created, the match between the expected state and the current state can be detected in a realistic search time by using the Bayesian attractor model. can do. It can be expected to appropriately detect a state change of a wireless system having a relatively high stability state because it repeats a simple operation such as an IoT data collection system.

<Embodiment 2>
Next, the second embodiment will be described. In the present embodiment, the estimation unit 113 estimates the packet loss rate by detecting the packet loss for periodic packet transmission by the data collection system 2 which is another data collection system. Is different from. In the following description, the same configuration and operation as in the first embodiment will be omitted as appropriate.

In the present embodiment, the packet loss rate is detected by the estimation unit 113 when the terminal device 23 periodically transmits data (wireless frame) to the gateway 22 in the data collection system 2. To estimate. Whether or not the terminal device 23 periodically transmits data to the gateway 22 is confirmed as follows, for example. The estimation unit 113 analyzes the reception status information about the transmission of the terminal device 23 obtained by the gateway 12 receiving the wireless frame transmitted by the terminal device 23. As a result, the estimation unit 113 detects that the same terminal device 23 is transmitting a radio frame to the gateway 22 at specific time intervals.

FIG. 7 is a graph showing an example of transition of received signal strength (RSSI: Received Signal Strength Indicator) for periodic radio frame transmission by the same terminal device 23. Further, FIG. 8 is a graph showing an example of the transition of the diffusion rate for the periodic transmission of the wireless frame by the same terminal device 23. The estimation unit 113 determines that packet loss has occurred when the wireless frame that should be periodically received by the gateway 12 is not received by the gateway 12.

Further, the terminal device 23 that detects the occurrence of packet loss by detecting that there is no response to the ACK request may increase the transmission output at the next transmission (see FIG. 7). Similarly, the terminal device 23 that has detected the occurrence of packet loss may increase the diffusion rate at the next transmission (see FIG. 8). Therefore, the estimation unit 113 causes packet loss when the gateway 12 receives a wireless frame having a higher reception signal strength or diffusion rate than the previous wireless frame reception with respect to the transmission of the wireless frame by the terminal device 23. It is determined that it has been done. As described above, the estimation unit 113 may determine that packet loss has occurred when the transmission output increases in the periodic packet transmission by the terminal device 23. Further, the estimation unit 113 may determine that packet loss has occurred when the diffusion rate in transmission increases in periodic packet transmission by the terminal device 23. The estimation unit 113 may use both the detection of packet loss by detecting that the radio frame that should be received periodically is not received and the detection of packet loss by detecting the increase in the received signal strength or the diffusion rate. However, either one may be adopted. Further, the detection of packet loss by detecting the increase in the received signal strength and the detection of the packet loss by detecting the increase in the diffusion rate may be used in combination, or either one may be adopted.

When packet loss occurs, the terminal device 23 may retransmit the lost data. In such a case, if the time from transmission once to retransmission is extremely short, the estimation unit 113 may misidentify the wireless frame transmitted by retransmission as a normally transmitted wireless frame. be. However, in a general IoT data collection system, as shown in FIG. 9, since it takes a sufficiently long time from transmission once to retransmission, such misidentification can be avoided. That is, in a general IoT data collection system, it is possible to appropriately detect the occurrence of retransmission.

The estimation unit 113 calculates the packet loss rate for each channel as follows, for example. First, the estimation unit 113 specifies that M times of transmission are performed in the _{T period} for a predetermined period by periodic transmission of the terminal device 23. _{Then, the estimation unit 113 counts the number of packet loss occurrences in the period Tape} , for example, by the above-mentioned detection method, and calculates the packet loss rate by the ratio of the count number to M. The estimation unit 113 may use the packet loss rate calculated in this way instead of the packet loss rate calculated by the calculation method described in the first embodiment (that is, the calculation by the equation (1)). That is, in step S102 described above, the loss rate calculated by the calculation method according to the present embodiment may be used. Also in this case, as in the first embodiment, the transmission rate and the capacity can be estimated, and the channel to be assigned to the terminal device 13 can be appropriately set. That is, even when a plurality of data collection systems compete with each other, wireless communication can be efficiently realized.

By the way, when the terminal device 23 transmits the wireless frame accompanied by the ACK request, the response from the network server 21 or the gateway 22 is generated immediately after that. Therefore, when the gateway 12 detects the transmission of the radio frame accompanied by the ACK request by the terminal device 23, the gateway 12 may avoid the timing of the response to the transmission and perform the transmission from the gateway 12. There is a delay time from the transmission by the terminal device 23 to the generation of the response. In LoRaWAN, this delay time is, for example, 1 second.

When the estimation unit 113 detects a radio frame in response to a radio frame from the terminal device 23, it may presume that the source of the radio frame in the response is the gateway 22 or the network server 21. This makes it possible to estimate the channel used by the gateway 22 or the network server 21 of the data collection system 2. In this case, the setting unit 114 may determine that the channel has a high probability of generating a radio signal, and may set the terminal device 13 or the gateway 12 so as to avoid using the channel. Whether or not the wireless frame received by the gateway 12 is a response to the wireless frame from the terminal device 23 is determined by, for example, the estimation unit 113 as follows. For example, if there is a wireless frame that occurs after a predetermined delay time (for example, after 1 second) with respect to the transmission of the wireless frame from the terminal device 23, this wireless frame is determined to be a response.

<Embodiment 3>
Next, the third embodiment will be described. In the above-described embodiment, the estimation unit 113 estimates the communication status of the radio channel by estimating the transmission rate and the communication capacity. In this embodiment, another estimation method of the communication status of the wireless channel will be described.

In the present embodiment, the estimation unit 113 determines the communication status of the radio channel from the present time onward by the other data collection system based on the cumulative data amount in the communication using the radio channel by the other data collection system. presume. This will be specifically described. The estimation unit 113 analyzes the cumulative value of the transmission data amount for each channel of the data collection system 2. This cumulative value is a cumulative value in a predetermined observation period. The IoT data collection system may be operated to collect a predetermined amount of data in a predetermined period. In this case, it means that there is an upper limit to the amount of communication data generated in a predetermined period. Therefore, in the present embodiment, the communication status of the wireless channel is estimated by paying attention to such a feature.

Specifically, in the estimation unit 113, for example, the cumulative data amount of the most recent first observation period by the communication of the data collection system 2 in a certain channel is predetermined with respect to the cumulative data amount of the past second observation period. Determine if the percentage has been reached. Here, the second observation period is longer than the first observation period. Then, when the cumulative data amount of the most recent first observation period reaches a predetermined ratio with respect to the cumulative data amount of the second observation period in the past, the estimation unit 113 causes the data collection system 2 in the channel. It is judged that the probability of occurrence of the communication after the present is temporarily low. Therefore, in this case, the setting unit 114 sets the terminal device 13 to use the channel. According to such a configuration, wireless communication can be efficiently realized even when a plurality of data collection systems compete with each other. For example, the estimation unit 113 compares the cumulative data amount of the most recent day (first observation period) with the maximum value or the average value of the cumulative data amount of the past one week (second observation period). Then, when the cumulative data amount for the most recent day reaches 95% of the maximum value or the average value of the cumulative data amount for one week, the estimation unit 113 almost completes the communication by the data collection system 2. Therefore, it is judged that the probability of subsequent communication is low for a while.

Further, the estimation unit 113 is based on the transition of the cumulative data amount from a predetermined time point to the present in the communication using the radio channel by the data collection system 2, and the data collection system 2 has the radio channel after the present. The communication status may be estimated. More specifically, the estimation unit 113 in the transition of the cumulative data amount of the third observation period from a predetermined time point to the present, in the latest fourth observation period, which is the period included in the third observation period. , Determine whether the increase in the cumulative data amount is less than or equal to the predetermined value. When the increase amount of the cumulative data amount in the fourth observation period is not more than a predetermined value, the estimation unit 113 determines that the probability of occurrence of the communication of the data collection system 2 in the channel after the present is temporarily low. Therefore, in this case, the setting unit 114 sets the terminal device 13 to use the channel. According to such a configuration, wireless communication can be efficiently realized even when a plurality of data collection systems compete with each other. For example, assume that the third observation period is the past one week to the present and the fourth observation period is the past three days to the present. In this case, for example, if the cumulative data amount does not change in the fourth observation period, it can be determined that the data collection by the data collection system 2 in the third observation period is completed.

Aggregation of the cumulative data amount may be performed for the channel group used for transmission of the radio frame with the same network ID. That is, the amount of data of a plurality of channels used by the data collection system 2 may be aggregated. Then, the communication status of these channel groups may be estimated. In the same data collection system 2, it is assumed that wireless frames with the same network ID are transmitted. Therefore, by aggregating the cumulative data amount of the wireless frames with the same network ID, it is possible to appropriately grasp the collection progress of the data collection system 2 that collects the data of the predetermined data amount in the predetermined period. ..

<Embodiment 4>
Next, the fourth embodiment will be described. In the present embodiment, another estimation method of the communication status of the wireless channel will be described.
Communication standards that use unlicensed radio frequency bands commonly used by IoT data collection systems may limit the amount of time that radio frames can be transmitted. For example, in the 920 MHz unlicensed band used by LoRaWAN, the total time per hour that a communication device belonging to the same system can transmit a wireless frame may be limited to 360 seconds or less. In such a case, for example, even if the number of packets that can be transmitted in 360 seconds at the maximum communication speed is 120, the communication amount (number of packets) per hour is also limited to 120. If the communication device attempts to transmit an amount of packets exceeding this due to packet transfer or the like, the packet may be discarded by the communication device.

In view of such characteristics of the IoT data collection system, in the estimation unit 113 of the present embodiment, the sum of the communication time of the communication using the wireless channel by the data collection system 2 in the specified period (for example, 1 hour) is set to a specified value (for example, 1 hour). For example, it is determined whether or not it exceeds 360 seconds). Then, the estimation unit 113 estimates the communication status of the radio channel from the present onward by the data collection system 2 based on the determination result. The estimation unit 113 analyzes the reception status information (specifically, for example, the wireless communication time) regarding the communication of the data collection system 2 as to whether or not the time during which the wireless frame can be transmitted is limited in the data collection system 2. You may confirm by doing so.

When the total of the communication time of the communication by the data collection system 2 in the specified period exceeds the specified value, it is determined that the probability of occurrence of the communication of the data collection system 2 in the channel after the present is temporarily low. Therefore, in this case, the setting unit 114 sets the terminal device 13 to use the channel. According to such a configuration, wireless communication can be efficiently realized even when a plurality of data collection systems compete with each other.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit. For example, each of the above-described embodiments may be combined.

In addition, some or all of the above embodiments may be described as in the following appendix, but are not limited to the following.

(Appendix 1)
An information processing device that manages the communication of the first data collection system.
An estimation means for estimating the communication status of a radio channel shared by the first data collection system and another data collection system based on the observation result of communication using the radio channel, and an estimation means.
An information processing device having a setting means for setting a channel used by a terminal device for wirelessly transmitting data collected in the first data collection system according to a communication condition estimated by the estimation means.
(Appendix 2)
The information processing apparatus according to Appendix 1, wherein the estimation means estimates a packet loss rate in the radio channel, and estimates the total transmission rate in the radio channel based on the packet loss rate.
(Appendix 3)
The estimation means estimates the packet loss rate based on a known transmission rate of the terminal device for transmitting data collected in the first data collection system and a reception rate observed for the terminal device. The information processing device according to Appendix 2.
(Appendix 4)
The information processing apparatus according to Appendix 2, wherein the estimation means estimates the packet loss rate by detecting packet loss for periodic packet transmission by the other data collection system.
(Appendix 5)
The information processing apparatus according to Appendix 4, wherein the estimation means determines that packet loss has occurred when the transmission output increases in periodic packet transmission.
(Appendix 6)
The information processing apparatus according to Appendix 4, wherein the estimation means determines that packet loss has occurred when the diffusion rate in transmission increases in periodic packet transmission.
(Appendix 7)
The information processing apparatus according to any one of Supplementary note 2 to 6, wherein the estimation means further estimates the communication capacity of the radio channel based on the observed signal noise ratio.
(Appendix 8)
The setting means includes the total number of the terminal devices that wirelessly transmit the data collected in the first data collection system, the number of available wireless channels, the estimated total transmission rate, and the estimated said. Based on the communication capacity, the number of the terminal devices accommodated in the wireless channel is determined, and the channel used by the terminal device for wirelessly transmitting the data collected in the first data collection system is set. Appendix 7 The information processing device described in.
(Appendix 9)
The estimation means estimates the communication status of the radio channel from the present by the other data collection system based on the cumulative data amount in the communication using the radio channel by the other data collection system. The information processing apparatus according to any one of 8.
(Appendix 10)
In the estimation means, the cumulative data amount of the most recent first observation period by communication of the other data collection system on the radio channel reaches a predetermined ratio with respect to the cumulative data amount of the past second observation period. The information processing apparatus according to Appendix 9, which estimates the communication status of the radio channel from the present time onward by the other data collection system based on whether or not the information processing device is used.
(Appendix 11)
The estimation means is based on the transition of the cumulative data amount from a predetermined time point to the present in the communication using the radio channel by the other data collection system, and the radio channel after the present by the other data collection system. The information processing apparatus according to Appendix 9, which estimates the communication status of the above.
(Appendix 12)
The estimation means is based on whether or not the sum of the communication times of the communication using the radio channel by the other data collection system in the specified period exceeds the specified value, and is based on the present or later by the other data collection system. The information processing apparatus according to any one of Supplementary note 1 to 11, which estimates the communication status of the radio channel of the above.
(Appendix 13)
It ’s a data collection system.
It is provided with an information processing device that manages communication of the data collection system and a terminal device that wirelessly transmits data collected in the data collection system.
The information processing device is
An estimation means that estimates the communication status of a radio channel shared by the data collection system and another data collection system based on the observation results of communication using the radio channel.
A data collection system having a setting means for setting a channel used by the terminal device according to a communication condition estimated by the estimation means.
(Appendix 14)
The estimation means estimates the communication status of the radio channel from the present by the other data collection system based on the cumulative data amount in the communication using the radio channel by the other data collection system. Described data collection system.
(Appendix 15)
The estimation means is based on whether or not the sum of the communication times of the communication using the radio channel by the other data collection system in the specified period exceeds the specified value, and is based on the present or later by the other data collection system. The data collection system according to Appendix 13 or 14, which estimates the communication status of the radio channel of the above.
(Appendix 16)
The communication status of the radio channel shared by the first data collection system and the other data collection system is estimated based on the observation result of the communication using the radio channel.
A communication setting method for setting a channel used by a terminal device that wirelessly transmits data collected in the first data collection system according to an estimated communication condition.
(Appendix 17)
For the computer of the information processing device that manages the communication of the data collection system,
An estimation step for estimating the communication status of a radio channel shared between the data collection system and another data collection system based on the observation result of communication using the radio channel, and an estimation step.
A program for executing a setting step of setting a channel used by a terminal device that wirelessly transmits data collected in the data collection system whose communication is managed by the information processing device according to the communication status estimated in the estimation step. A non-temporary computer-readable medium that contains.

Although the invention of the present application has been described above with reference to the embodiments, the invention of the present application is not limited to the above. Various changes that can be understood by those skilled in the art can be made within the scope of the invention in the configuration and details of the invention of the present application.

This application claims priority on the basis of Japanese application Japanese Patent Application No. 2019-048658 filed on March 15, 2019, the entire disclosure of which is incorporated herein by reference.

1 Data collection system 2 Data collection system 10 Application server 11 Network server 12 Gateway 13 Terminal device 20 Application server 21 Network server 22 Gateway 23 Terminal device 50 Network interface 51 Memory 52 Processor 110 Transmission / reception unit 111 Packet processing unit 113 Estimating unit 114 Setting unit

Claims (17)

An information processing device that manages the communication of the first data collection system.
An estimation means for estimating the communication status of a radio channel shared by the first data collection system and another data collection system based on the observation result of communication using the radio channel, and an estimation means.
An information processing device having a setting means for setting a channel used by a terminal device for wirelessly transmitting data collected in the first data collection system according to a communication condition estimated by the estimation means. The information processing apparatus according to claim 1, wherein the estimation means estimates a packet loss rate in the radio channel, and estimates the total transmission rate in the radio channel based on the packet loss rate. The estimation means estimates the packet loss rate based on a known transmission rate of the terminal device for transmitting data collected in the first data collection system and a reception rate observed for the terminal device. The information processing apparatus according to claim 2. The information processing apparatus according to claim 2, wherein the estimation means estimates the packet loss rate by detecting packet loss for periodic packet transmission by the other data collection system. The information processing apparatus according to claim 4, wherein the estimation means determines that packet loss has occurred when the transmission output increases in periodic packet transmission. The information processing apparatus according to claim 4, wherein the estimation means determines that packet loss has occurred when the diffusion rate in transmission increases in periodic packet transmission. The information processing apparatus according to any one of claims 2 to 6, wherein the estimation means further estimates the communication capacity of the radio channel based on the observed signal noise ratio. The setting means includes the total number of the terminal devices that wirelessly transmit the data collected in the first data collection system, the number of available wireless channels, the estimated total transmission rate, and the estimated said. A claim that determines the number of the terminal devices accommodated in the radio channel based on the communication capacity, and sets the channel used by the terminal device that wirelessly transmits the data collected in the first data collection system. The information processing apparatus according to 7. The estimation means estimates the communication status of the radio channel from the present by the other data collection system based on the cumulative data amount in the communication using the radio channel by the other data collection system. The information processing apparatus according to any one of 8 to 8. In the estimation means, the cumulative data amount of the most recent first observation period by communication of the other data collection system on the radio channel reaches a predetermined ratio with respect to the cumulative data amount of the past second observation period. The information processing apparatus according to claim 9, which estimates the communication status of the radio channel from the present time onward by the other data collection system based on whether or not the information processing device is used. The estimation means is based on the transition of the cumulative data amount from a predetermined time point to the present in the communication using the radio channel by the other data collection system, and the radio channel after the present by the other data collection system. The information processing apparatus according to claim 9, which estimates the communication status of the above. The estimation means is based on whether or not the sum of the communication times of the communication using the radio channel by the other data collection system in the specified period exceeds the specified value, and is based on the present or later by the other data collection system. The information processing apparatus according to any one of claims 1 to 11, which estimates the communication status of the radio channel. It ’s a data collection system.
It is provided with an information processing device that manages communication of the data collection system and a terminal device that wirelessly transmits data collected in the data collection system.
The information processing device is
An estimation means that estimates the communication status of a radio channel shared by the data collection system and another data collection system based on the observation results of communication using the radio channel.
A data collection system having a setting means for setting a channel used by the terminal device according to a communication condition estimated by the estimation means. The estimation means estimates the communication status of the radio channel from the present by the other data collection system based on the cumulative data amount in the communication using the radio channel by the other data collection system. The data collection system described in. The estimation means is based on whether or not the sum of the communication times of the communication using the radio channel by the other data collection system in the specified period exceeds the specified value, and is based on the present or later by the other data collection system. The data collection system according to claim 13 or 14, which estimates the communication status of the radio channel. The communication status of the radio channel shared by the first data collection system and the other data collection system is estimated based on the observation result of the communication using the radio channel.
A communication setting method for setting a channel used by a terminal device that wirelessly transmits data collected in the first data collection system according to an estimated communication condition. For the computer of the information processing device that manages the communication of the data collection system,
An estimation step for estimating the communication status of a radio channel shared between the data collection system and another data collection system based on the observation result of communication using the radio channel, and an estimation step.
A program for executing a setting step of setting a channel used by a terminal device that wirelessly transmits data collected in the data collection system whose communication is managed by the information processing device according to the communication status estimated in the estimation step. A non-temporary computer-readable medium that contains.

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