JP7259937B2 - Information processing device, communication setting method, and program - Google Patents

Description

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

In recent years, along 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, with the introduction of smart meters for electricity, gas, water, etc., collecting more detailed data from sensors in real time is expected to enable rapid failure detection and more efficient operation. . Smart meters are expected to utilize LPWA (Low Power Wide Area), which is a wireless communication method with a long communication distance. LPWA is a wireless communication that uses a radio frequency band that can be used without a license (unlicensed band). Compared to Wi-Fi, the communication speed is slower, but the communication distance is longer and the power consumption is lower. be. As LPWA, for example, LORA, SIGFOX, Wi-SUN, etc. are known.

As data collection services utilizing LPWA (Internet of Things (IoT) data collection systems) become widely used, it is expected that the data collection services will compete in the use of wireless resources. In particular, in LPWA, which has a long communication distance and a low communication speed, the available communication capacity per unit area is small, which may pose a serious problem.

For this reason, it is thought that control technology will be required to optimize the use of radio waves and optimize the quality of data collection services. 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 using this as an input A system for state estimation and decision making is disclosed.

Kominami, Suzuki, Hasegawa, Shimonishi, Murata, "Wireless channel assignment method in LPWA network using brain cognitive model", IEICE Technical Report, vol.118, no.6, pp.7-12, 2018

As noted above, multiple data collection systems may conflict over the use of radio resources.
Accordingly, one object of the present disclosure is 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. is to provide

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

A data collection system according to a second aspect includes:
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
estimation means for estimating the communication status of a radio channel shared by the data collection system and another data collection system based on observation results of communication using the radio channel;
setting means for setting a channel to be used by the terminal device according to the communication status estimated by the estimation means.

In the communication setting method according to the third aspect,
estimating the communication status of a radio channel shared by the first data collection system and the other data collection system based on observation results of communication using the radio channel;
A channel to be used by a terminal device that wirelessly transmits data collected in the first data collection system is set according to the estimated communication status.

A program according to a fourth aspect,
In the computer of the information processing device that manages the communication of the data collection system,
an estimation step of estimating the communication status of a radio channel shared by the data collection system and another data collection system based on observation results of communication using the radio channel;
a setting step of setting a channel to be 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.

According to the above aspect, it is possible 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.

1 is a block diagram showing an example of a configuration of a network server according to an outline of an embodiment; FIG. 1 is a block diagram showing an example of the configuration of a data collection system according to an embodiment; FIG. FIG. 4 is a table showing examples of data rates; FIG. 3 is a block diagram showing an example of a specific configuration of a network server according to an embodiment; FIG. 3 is a block diagram showing an example of a hardware configuration of a network server according to an embodiment; FIG. 4 is a flow chart showing an example of the flow of operations for channel setting according to Embodiment 1. FIG. FIG. 4 is a graph showing an example of changes in received signal strength for periodic transmission of radio frames by the same terminal device; FIG. FIG. 10 is a graph showing an example of transition of spreading factor for periodical transmission of radio frames by the same terminal device; FIG. FIG. 11 is a graph showing an example of changes in received signal strength when there is retransmission; FIG.

Prior to detailed description of the embodiments, an outline of the embodiments will be described.
FIG. 1 is a block diagram showing an example of the configuration of a network server 11 according to the outline of the embodiment. The network server 11 belongs to a data collection system and is a device that manages communication of the data collection system. This data collection system includes a terminal device that wirelessly transmits data collected in the data collection system for collection. The network server 11 is sometimes called 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 a wireless channel shared by the data collection system to which the network server 11 belongs and other data collection systems, based on observation results of communication using the wireless channel.
The setting unit 114 sets the channel to be used by the terminal device 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 a wireless channel shared by a plurality of data collection systems is estimated, and channel setting is performed according to the estimation result. Therefore, wireless communication can be efficiently realized even when a plurality of data collection systems compete with each other.

Next, 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 has an application server 10 , a network server 11 , a gateway 12 and terminal devices (user nodes) 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 has 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 they are not limited to this, and may be systems that perform communication conforming to other LPWA standards. 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 should be at least one, but typically there are many terminal devices 23 .

Although one data collection system 2 is illustrated in FIG. 2, a plurality of data collection systems 2 may exist. That is, there may be multiple data collection systems competing 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 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 network server 21 .

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

The terminal device 13 stores sensor data such as the amount of gas used, the amount of electricity used, or a water level gauge in a wireless frame and transmits the wireless frame to the gateway 12 . Similarly, the terminal device 23 also stores the sensor data in a radio frame and transmits it toward 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 areas overlap between the two systems. However, the gateway 12 cannot necessarily receive the wireless frame of the terminal device 23, and even if it can receive the wireless frame, it cannot always read the contents of the wireless frame. The terminal device 13 is under control of the network server 11 of the data collection system 1 , and the terminal device 13 is under 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, the data collection system 1 cannot control the terminal device 23 by changing its settings.

The terminal device 13 is preset by the network server 11 with the transmission timing of the wireless frame and the wireless channel to be used at the time of transmission of the wireless frame. Similarly, the terminal device 23 is preset by the network server 21 with the transmission timing of the wireless frame and the wireless channel to be used when transmitting the wireless frame. For example, the terminal devices 13 and 23 periodically transmit radio frames at predetermined time intervals.

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

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

The radio communication time is the time during which radio waves are used to transmit radio frames, and is also called TOA (Time on air). A network ID is an identifier that specifies which data collection system the network is used in, that is, which data collection system the transmission source terminal device belongs to. A device ID is an identifier that identifies a terminal device that is a transmission source. A data rate is control information that defines the spreading factor and bandwidth of a radio signal, and is defined as shown in FIG. 3 in LoRaWAN, for example. The ACK request is control information requesting the destination of a radio frame (packet) to respond to the destination of the radio frame (packet).

The received signal strength, signal-to-noise ratio, wireless communication time, reception time, and used wireless channel are obtained, for example, by the gateway 12 observing wireless signals. For network ID, device ID, destination, ACK request, data rate, spreading factor of radio signal, transmission power, and transmission time, for example, the gateway 12 observes (reads) these information stored in the radio frame. obtained by

The network server 11 accumulates the reception status information stored in the packets 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 communication using the radio channel. Also, the network server 11 performs settings for controlling transmission in the terminal device 13 according to the estimated communication status. 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. As shown in FIG. 4, it has a transmitting/receiving section 110 , a packet processing section 111 , an estimating section 113 and a setting section 114 .

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

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

Estimating section 113 estimates the wireless communication status by accumulating reception status information and analyzing it. Also, the setting unit 114 performs 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 transmitting/receiving unit 110 as a command. Upon receiving the command, the terminal device 13 performs radio frame transmission processing according to the setting contents. Note that 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. As shown in FIG. 5, network server 11 includes network interface 50, memory 51, and processor 52, for example.

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

The memory 51 is configured by, for example, a combination of volatile memory and nonvolatile 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 provided to computers using various types of non-transitory computer readable media. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (eg, floppy disks, magnetic tapes, hard disk drives), magneto-optical recording media (eg, magneto-optical discs), Compact Disc Read Only Memory (CD-ROM), CD- 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 on various types of transitory computer readable medium. Examples of transitory computer-readable media include electrical signals, optical signals, and electromagnetic waves. Transitory computer-readable media can deliver the program to the computer via wired channels, such as wires and optical fibers, or wireless channels.

The processor 52 reads and executes software (computer program) from the memory 51 to process each component shown in FIG. That is, each process of the transmitting/receiving unit 110, the packet processing unit 111, the estimating unit 113, and the setting unit 114 may be realized by executing a program. In this manner, the network server 11 functions as a computer. The processor 52 may be, for example, a microprocessor, an MPU (Micro Processor Unit), or a CPU (Central Processing Unit). Processor 52 may include multiple processors.

Next, specific processing of estimation section 113 and setting section 114 in the present embodiment will be described. The estimating unit 113 of the present embodiment estimates the following two index values in order to estimate the radio wave usage congestion state (communication state) for each wireless channel. That is, the estimation unit 113 uses the total transmission rate of the terminal device 13 belonging to the data collection system 1 and the terminal device 23 belonging to the other data collection system (all competing data collection systems 2) as the first index ( (also called total transmission rate). Also, the estimation unit 113 estimates the communication capacity of each wireless channel as a 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, this embodiment focuses on the loss rate, which indicates the frequency of events in which the terminal devices 13 and 23 transmit but the destination gateways 12 and 22 cannot receive them due to radio wave interference or the like. .
In this embodiment, it is assumed that the transmission rate of at least one terminal device 13 among the terminal devices 13 belonging to the data collection system 1 is known. At this time, the estimator 113 estimates the loss rate P from the transmission rate of this terminal device 13 and the reception rate of the transmission of this terminal device 13 using the following equation (1). The reception rate is calculated from the actual reception result of the gateway 12 with respect to the transmission of the terminal device 13 whose transmission rate is known. That is, the reception rate is obtained by the estimation section 113 analyzing the reception status information about the radio frame transmitted from the terminal device 13 . In equation (1), RXRate indicates a known transmission rate, and TXRate indicates a reception rate obtained as an actual observation result.

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

Here, the loss rate P is expressed as 1-(arrival rate). Also, the arrival rate is expressed as the ratio of the reception rate to the transmission rate. Therefore, according to the above formula (2), the relationship of the following formula (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 Equation (4) below.

Here, assuming that the loss rate on the channel i of interest is P _i , the total TXRate _i of the transmission rates of the terminal devices 13 and 23 on the channel i is expressed by the following equation (5). Note that P _i 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 equation (1) above.

As described above, in the present embodiment, the transmission rate is estimated in the following manner on the assumption of the characteristic communication method used in the IoT data collection system at the time of estimation. That is, the estimation unit 113 first estimates the packet loss rate P _i on the channel i from part of the communication observed in its own system (data collection system 1). Estimating section 113 then uses equation (5) to estimate transmission rate TXRate _i , which is the combination of the transmission rate of terminal device 13 of the own system and the transmission rate of terminal device 23 of the other system. Thus, the estimator 113 estimates the packet loss rate in the wireless channel, and estimates the total transmission rate in the wireless channel based on the packet loss rate.

Next, 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 notifies the network server 11 of reception status information including the signal-to-noise ratio (SNR) when transferring radio frames to the network server 11 .
The estimating unit 113 estimates the effective communication capacity Capacity _i of the wireless channel i of interest using the approximation of the Shannon-Hartley theorem, using the following equation (6).

In equation (6), _SNRi represents the observed signal-to-noise ratio of channel i, SNRrange represents the measurable range of the signal-to-noise ratio, and SNRlow represents the lower limit of the SNRrange. Thus, the estimation unit 113 estimates the effective communication capacity for each radio channel from the signal-to-noise ratio observed for each radio channel.

In the present embodiment _, for channel _i , setting section 114 sets channel The terminal device 13 accommodated 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 to switch to. That is, the setting unit 114 calculates the maximum number of terminals 13 that can be accommodated in each channel. A method for calculating the number of terminal devices 13 to be accommodated in each channel, that is, a method for calculating the maximum number of terminal devices 13 to be accommodated in each channel will be described below.

The setting unit 114 uses the estimated transmission rate TXRate _i and 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 accommodated number n _i of the terminal devices 13 of the channel i by the following equation (7).

Note that 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 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 total number of users that can be accommodated), and is specifically expressed by the following equation (8).

Note that in equations (7) and (8), _Wi is represented by the following equation (9). That is, W _i is the inverse of the congestion degree of channel i (ie, TXRate _i /Capacity _i ).

Note that it is preferable to limit n _i so that the utilization rate of each channel does not exceed one. Therefore, n _i preferably satisfies the following formula (10), that is, the relational expression of formula (11). That is, n _i is preferably limited to less than T/A.

Note that in Equation (10), Link_util _i represents the utilization rate of channel i. TOA _i represents the time (Time on air) during which 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. Also, in 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 flow chart showing an example of the flow of operations for channel setting in this embodiment. The flow of operation will be described below with reference to FIG.

In step S100, the terminal device 13 whose transmission rate is known transmits a radio frame using channel i.

Next, in step S101, the gateway 12 receives the radio frame and transfers reception status information including the signal-to-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 transmission of the terminal device 13 based on the reception status information acquired in step S101. Estimating section 113 then calculates the loss rate of channel i according to equation (1) using this reception rate and the known transmission rate. Thus, in the present embodiment, the estimation unit 113, 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 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 Equation (5).

Next, in step S104, the estimation unit 113 of the network server 11 estimates the communication capacity of channel i according to 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 for channel i is equal to or less than a threshold. If either is equal to or less than the threshold, the process proceeds to step S106. If any of them exceeds the threshold, the channel setting change is omitted. In the example shown in FIG. 6, the condition for moving to step S106 is that the transmission rate or the communication capacity is equal to or less than the threshold. good.

Next, in step S106, the setting unit 114 calculates the maximum number of terminals 13 that can be accommodated in each channel according to Equation (7). That is, 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, the setting unit 114 determines the number of terminal devices to be accommodated in the wireless channels. to decide.

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

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 signal-to-noise ratio caused by the operation of other data collection systems 2 sharing radio 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. The terminal device 13 that has received the notification performs data transmission using the newly designated channel. As a result, it is possible to appropriately control the system to be managed without directly using the communication volume 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 formulas described above. However, the amount of calculation may be reduced. Bayesian estimation has the feature that estimation is possible even with a small amount of information. In addition, even if a probability distribution is created for a combination of multiple states such as transmission rate and capacity, by using a Bayesian attractor model, it is possible to detect a match between the assumed state and the current state in a realistic search time. can do. Like the IoT data collection system, it can be expected to appropriately detect state changes in a wireless system that has relatively high stability due to repeated simple operations.

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

In this embodiment, the packet loss rate 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 . Thereby, the estimation unit 113 detects that the same terminal device 23 is transmitting radio frames to the gateway 22 at specific time intervals.

FIG. 7 is a graph showing an example of changes in received signal strength indicator (RSSI) for periodical transmission of radio frames by the same terminal device 23 . FIG. 8 is a graph showing an example of transition of the spreading factor for periodical transmission of radio frames by the same terminal device 23. In FIG. The estimating unit 113 determines that a packet loss has occurred when the gateway 12 does not receive wireless frames that should be received by the gateway 12 periodically.

In addition, the terminal device 23 that detects the occurrence of packet loss by detecting no response to the ACK request may increase the transmission output in the next transmission (see FIG. 7). Similarly, the terminal device 23 that has detected the occurrence of packet loss may increase the spreading factor in the next transmission (see FIG. 8). For this reason, the estimating unit 113 determines that when the gateway 12 receives a radio frame with an increased received signal strength or a spreading factor compared to the time of the previous radio frame reception, packet loss occurs. It is determined that In this way, the estimation unit 113 may determine that a packet loss has occurred when the transmission output power increases during periodic packet transmission by the terminal device 23 . Also, the estimating unit 113 may determine that a packet loss has occurred when the spreading factor in transmission increases in periodic packet transmission by the terminal device 23 . The estimation unit 113 may detect packet loss by detecting that radio frames that should be received periodically are not received, and detect packet loss by detecting an increase in received signal strength or spreading factor. and either one may be used. Also, detection of packet loss by detection of increase in received signal strength and detection of packet loss by detection of increase in spreading factor may be used in combination, or either one of them may be adopted.

Note that the terminal device 23 may resend the lost data when a packet loss occurs. In such a case, if the time from once transmission to retransmission is extremely short, there is a possibility that the estimation unit 113 misidentifies the radio frame transmitted by retransmission as a normally transmitted radio frame. be. However, in a general IoT data collection system, as shown in FIG. 9, the time from transmission to retransmission is sufficiently long, so such misidentification can be avoided. That is, in a general IoT data collection system, it is possible to appropriately detect the occurrence of retransmission.

For example, the estimation unit 113 calculates the packet loss rate for each channel as follows. The estimating unit 113 first identifies that the periodic transmission of the terminal device 23 is performed M times in a predetermined period T _period . Then, the estimating unit 113 counts the number of occurrences of packet losses in the period T _period , for example, by the detection method described above, and calculates the packet loss rate from the ratio between this count number and M. The estimating unit 113 may use the packet loss rate calculated in this manner instead of the packet loss rate calculated by the calculation method described in Embodiment 1 (that is, the calculation using formula (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, it is possible to estimate the transmission rate and capacity, and appropriately set the channel to be assigned to the terminal device 13 . In other words, wireless communication can be efficiently realized even when a plurality of data collection systems compete with each other.

By the way, when the terminal device 23 transmits a radio frame with an ACK request, a response from the network server 21 or the gateway 22 will occur immediately after that. Therefore, when the gateway 12 detects transmission of a radio frame accompanied by an ACK request by the terminal device 23, the gateway 12 may avoid the timing of the response to the transmission and perform transmission from the gateway 12. FIG. Note that there is a delay time from transmission by the terminal device 23 to generation of a response. This delay time is, for example, 1 second in LoRaWAN.

When the estimation unit 113 detects a wireless frame in response to the wireless frame from the terminal device 23 , the estimation unit 113 may estimate that the gateway 22 or the network server 21 is the source of the wireless frame in response. This makes it possible to estimate the channel used by the gateway 22 or 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 set the terminal device 13 or the gateway 12 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 the estimation unit 113 as follows, for example. For example, if there is a radio frame generated after a predetermined delay time (for example, 1 second) from the transmission of the radio frame from the terminal device 23, this radio frame is determined to be a response.

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

In this embodiment, the estimating unit 113 estimates the current communication status of the wireless channel by the other data collection system based on the accumulated data amount in the communication using the wireless channel by the other data collection system. presume. This will be explained in detail. 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. An 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 that occurs in a predetermined period. Therefore, in the present embodiment, attention is focused on such characteristics to estimate the communication status of the radio channel.

Specifically, the estimating unit 113 determines that, for example, the accumulated data amount in the most recent first observation period through communication of the data collection system 2 on a certain channel is a predetermined amount with respect to the accumulated data amount in the past second observation period. Determine whether or not the percentage has been reached. Here, the second observation period is longer than the first observation period. Then, when the accumulated data amount in the most recent first observation period has reached a predetermined ratio with respect to the accumulated data amount in the past second observation period, the estimation unit 113 It is determined that the probability of occurrence of this 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 estimating unit 113 compares the accumulated data amount for the most recent day (first observation period) with the maximum or average accumulated data amount for one past week (second observation period). Then, the estimation unit 113 determines that the communication by the data collection system 2 is almost completed when the cumulative data amount for the most recent day has reached 95% of the maximum value or the average value of the cumulative data amount for one week. Therefore, it is judged that the probability of occurrence of subsequent communication is low for a while.

In addition, the estimation unit 113 calculates, based on the change in the amount of accumulated data from a predetermined point in time to the present in communication using a certain wireless channel by the data acquisition system 2, the Communication status may be estimated. More specifically, the estimating unit 113 determines that, in the transition of the cumulative data amount in the third observation period from a predetermined time point to the present, in the most recent fourth observation period that is included in the third observation period , determines whether or not the amount of increase in the cumulative data amount is equal to or less than a predetermined value. The estimating unit 113 determines that the probability of future communication of the data collection system 2 on the channel is temporarily low when the increase in the cumulative amount of data during the fourth observation period is equal to or less than a predetermined value. 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 accumulated data amount does not change in the fourth observation period, it can be determined that the data collection in the third observation period by the data collection system 2 has been completed.

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

<Embodiment 4>
Next, Embodiment 4 will be described. In this embodiment, still another method for estimating the communication status of a wireless channel will be described.
In communication standards that use unlicensed radio frequency bands that are generally used by IoT data collection systems, there are cases where the time during which radio frames can be transmitted is limited. For example, in the 920 MHz unlicensed band used by LoRaWAN, the time during which communication devices belonging to the same system can transmit radio frames may be limited to a total of 360 seconds or less per hour. 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 amount of communication (number of packets) per hour is similarly limited to 120. If the communication device attempts to transmit packets exceeding this amount for reasons such as packet transfer, the packets may be discarded by the communication device.

In view of such characteristics of the IoT data collection system, the estimating unit 113 of the present embodiment determines that the total communication time of the communication using the wireless channel by the data collection system 2 in a specified period (for example, one hour) is a specified value ( for example, 360 seconds). Based on the determination result, the estimation unit 113 estimates the communication status of the radio channel from now on by the data collection system 2 . In the data collection system 2, the estimation unit 113 analyzes the reception status information (specifically, the radio communication time, for example) regarding the communication of the data collection system 2 to determine whether the time during which the radio frame can be transmitted is limited. can be confirmed by

If the sum of the communication times of the data collection system 2 during the specified period exceeds the specified value, it is temporarily determined that the probability of future occurrence of the communication of the data collection system 2 on the channel is 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.

It should be noted that the present invention is not limited to the above embodiments, and can be modified as appropriate without departing from the scope of the invention. For example, each embodiment mentioned above may be combined.

In addition, part or all of the above-described embodiments can be described as the following additional remarks, but are not limited to the following.

(Appendix 1)
An information processing device that manages communication of a first data collection system,
estimating means for estimating the communication status of a radio channel shared by the first data collection system and another data collection system based on observation results of communication using the radio channel;
and setting means for setting a channel to be used by a terminal device that wirelessly transmits data collected in the first data collection system according to the communication status 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 wireless channel and estimates a total transmission rate in the wireless 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 that transmits data collected in the first data collection system and an observed reception rate of the terminal device. The information processing device according to appendix 2.
(Appendix 4)
The information processing apparatus according to appendix 2, wherein the estimating means estimates the packet loss rate by detecting packet loss in periodic packet transmission by the other data collection system.
(Appendix 5)
The information processing apparatus according to appendix 4, wherein the estimating means determines that a packet loss has occurred when a transmission output increases in periodic packet transmission.
(Appendix 6)
The information processing apparatus according to appendix 4, wherein the estimating means determines that a packet loss has occurred when a spreading factor in transmission increases in periodic packet transmission.
(Appendix 7)
The information processing apparatus according to any one of appendices 2 to 6, wherein the estimation means further estimates the communication capacity of the radio channel based on the observed signal-to-noise ratio.
(Appendix 8)
The setting means includes the total number of terminal devices that wirelessly transmit data collected in the first data collection system, the number of available wireless channels, the estimated total transmission rate, and the estimated determining the number of the terminal devices to be accommodated in the wireless channel based on the communication capacity, and setting the channel to be used by the terminal device that wirelessly transmits the data collected in the first data collection system. The information processing device according to .
(Appendix 9)
The estimating means estimates the communication status of the radio channel from the present onward by the other data collection system based on the accumulated data amount in the communication using the radio channel by the other data collection system. 9. The information processing apparatus according to any one of 8.
(Appendix 10)
The estimating means is configured such that the accumulated data amount in the most recent first observation period through communication of the other data collection system on the wireless channel reaches a predetermined ratio with respect to the accumulated data amount in the past second observation period. The information processing apparatus according to appendix 9, wherein the communication status of the wireless channel after the present is estimated by the other data collection system based on whether or not the wireless channel is connected.
(Appendix 11)
The estimating means, based on the transition of the amount of accumulated data from a predetermined point in time to the present in the communication using the radio channel by the other data collection system, the radio channel after the present by the other data collection system The information processing device according to appendix 9.
(Appendix 12)
The estimating means, based on whether or not the sum of the communication time of the communication using the wireless channel by the other data collection system in a prescribed period exceeds a prescribed value, 12. The information processing apparatus according to any one of appendices 1 to 11, wherein the communication status of the wireless channel is estimated.
(Appendix 13)
A data collection system comprising:
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
estimation means for estimating the communication status of a radio channel shared by the data collection system and another data collection system based on observation results of communication using the radio channel;
A data collection system comprising: setting means for setting a channel to be used by the terminal device according to the communication status estimated by the estimation means.
(Appendix 14)
The estimating means estimates the communication status of the radio channel from the present onward by the other data collection system based on the accumulated data amount in the communication using the radio channel by the other data collection system. Data collection system as described.
(Appendix 15)
The estimating means, based on whether or not the sum of the communication time of the communication using the wireless channel by the other data collection system in a prescribed period exceeds a prescribed value, 15. The data collection system according to appendix 13 or 14, which estimates the communication status of the wireless channel of
(Appendix 16)
estimating the communication status of a radio channel shared by the first data collection system and the other data collection system based on observation results of communication using the radio channel;
A communication setting method of setting a channel to be used by a terminal device that wirelessly transmits data collected in the first data collection system according to the estimated communication status.
(Appendix 17)
In the computer of the information processing device that manages the communication of the data collection system,
an estimation step of estimating the communication status of a radio channel shared by the data collection system and another data collection system based on observation results of communication using the radio channel;
a setting step of setting a channel to be 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-transitory computer-readable medium on which is stored.

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

This application claims priority based on Japanese Patent Application No. 2019-048658 filed on March 15, 2019, and the entire disclosure thereof is incorporated herein.

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 estimation unit 114 setting unit

Claims (10)

An information processing device that manages communication of a first data collection system,
estimating means for estimating the communication status of a radio channel shared by the first data collection system and another data collection system based on observation results of communication using the radio channel;
setting means for setting a channel to be used by a terminal device that wirelessly transmits data collected in the first data collection system according to the communication status estimated by the estimation means ;
The estimating means estimates a packet loss rate in the radio channel and estimates a total transmission rate in the radio channel based on the packet loss rate.
Information processing equipment. The estimation means estimates the packet loss rate based on a known transmission rate of the terminal device that transmits data collected in the first data collection system and an observed reception rate of the terminal device. The information processing device according to claim 1 . 2. The information processing apparatus according to claim 1 , wherein said estimating means estimates said packet loss rate by detecting packet loss in periodic packet transmission by said another data collection system. 4. The information processing apparatus according to any one of claims 1 to 3 , wherein said estimating means further estimates the communication capacity of said radio channel based on the observed signal-to-noise ratio. The setting means includes the total number of terminal devices that wirelessly transmit data collected in the first data collection system, the number of available wireless channels, the estimated total transmission rate, and the estimated determining the number of said terminal devices to be accommodated in said wireless channel based on said communication capacity, and setting a channel to be used by said terminal device for wirelessly transmitting data collected in said first data collection system. 5. The information processing device according to 4 . An information processing device that manages communication of a first data collection system,
estimating means for estimating the communication status of a radio channel shared by the first data collection system and another data collection system based on observation results of communication using the radio channel;
setting means for setting a channel to be used by a terminal device that wirelessly transmits data collected in the first data collection system according to the communication status estimated by the estimation means;
has
The estimating means estimates the communication status of the radio channel from the present onward by the other data collection system based on the accumulated data amount in the communication using the radio channel by the other data collection system.
Information processing equipment. estimating the communication status of a radio channel shared by the first data collection system and the other data collection system based on observation results of communication using the radio channel;
setting a channel to be used by a terminal device that wirelessly transmits data collected in the first data collection system according to the estimated communication situation ;
The estimation includes estimating a packet loss rate on the wireless channel and estimating a total transmission rate on the wireless channel based on the packet loss rate.
How to set up communication. estimating the communication status of a radio channel shared by the first data collection system and the other data collection system based on observation results of communication using the radio channel;
setting a channel to be used by a terminal device that wirelessly transmits data collected in the first data collection system according to the estimated communication situation;
In the estimation, based on the amount of accumulated data in the communication using the radio channel by the other data collection system, the communication status of the radio channel after the present is estimated by the other data collection system.
How to set up communication. In the computer of the information processing device that manages the communication of the data collection system,
an estimation step of estimating the communication status of a radio channel shared by the data collection system and another data collection system based on observation results of communication using the radio channel;
a setting step of setting a channel to be 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 ;
The estimating step estimates a packet loss rate in the wireless channel, and estimates a total transmission rate in the wireless channel based on the packet loss rate.
program. In the computer of the information processing device that manages the communication of the data collection system,
an estimation step of estimating the communication status of a radio channel shared by the data collection system and another data collection system based on observation results of communication using the radio channel;
a setting step of setting a channel to be 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;
and
In the estimating step, based on the amount of accumulated data in the communication using the radio channel by the other data collection system, the communication status of the radio channel after the present is estimated by the other data collection system.
program.

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