JP7272189B2 - Information processing device, wireless communication system, information processing method and program - Google Patents

Description

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

In recent years, ICT (Information and Communication Technology) systems utilizing wireless networks have been introduced into factories and the like for the purpose of improving productivity and safety. For example, a server on the network monitors the operational status of production equipment via a wireless network using sensors. The server quickly detects problems such as failures of production equipment based on the results collected from the sensors.

Alternatively, a server on the network may track the employee's location via a wireless network and analyze work wait times and waste. The analysis makes it possible to improve production efficiency.

Here, it is normal for the environment and situation of the wireless network to change according to time. For example, information may be collected from sensors via a wireless network in a place such as a factory where the environment is subject to frequent layout changes. It is not easy to build a stable wireless network in places where the radio wave conditions change greatly, and it is required to quickly analyze the cause of wireless communication failures.

As a method of identifying the cause of radio failure, there is a method of capturing transmitted and received radio frames and analyzing the captured data. For example, Non-Patent Documents 1 and 2 describe analyzing a captured radio frame and displaying its protocol information and statistical information.

In addition, in Non-Patent Document 3, a transition model for initial transmission, retransmission, and acknowledgment (ACK; Acknowledgment) is constructed from the specifications of the wireless communication protocol, and state transitions when there is a capture loss are added to the transition model. It is disclosed to In Non-Patent Document 3, paths that can explain captured data are listed, and the behavior of the terminal during the period when no capture is performed is estimated by selecting the path with the fewest transitions related to capture loss.

Wireshark, August 2, 2019, [online], Internet <URL: https://www.wireshark.org/> Metageek, “Eye P.A. Essential: Powerful Multi-Channel Packet Analysis”, August 2, 2019, [online], Internet <URL: https://www.metageek.com/products/eye-pa/> Ratul Mahajan, etc., “Analyzing the MAC-level behavior of wireless networks in the wild,” SIGOMM’06, September 11-15 2006

As mentioned above, in order to determine the state of the wireless communication system, there are methods of installing a radio frame monitor device in the system and evaluating the wireless communication system based on the captured data. For example, in order to determine the state of the wireless communication system (occurrence of failure or non-occurrence of failure), a "retransmission rate" indicating the ratio of retransmission frames to all communication frames is calculated. An evaluation method (failure detection method) using such a monitor device has the advantage that failure detection can be performed without modifying the existing system.

On the other hand, there is no guarantee that the monitor device can capture all communication frames transmitted and received between the terminal and the access point (or base station), and normally there may be frames that the monitor device cannot capture. Radio frames with a low transmission rate are often easier to capture than radio frames with a high transmission rate. As a result, the radio frames that can be captured by the monitor device are biased (many radio frames with low transmission rates are captured).

Here, let us consider terminal retransmission control. The terminal transmits a radio frame containing predetermined data to the access point as an "initial transmission frame". A high value is set for the transmission rate of the first transmission frame. This is because the higher the transmission rate, the larger the amount of data that can be transmitted per unit time, which is advantageous. However, if the transmission rate is high, there is a high possibility that the access point will not be able to receive the initial transmission frame. If the access point fails to receive the initial transmission frame, the terminal cannot receive an acknowledgment from the access point, so it transmits to the access point a "retransmission frame" containing the same data as the initial transmission frame.

The transmission rate set for the retransmission frame is set lower than the transmission rate for the initial transmission frame. This is because if the transmission rate is the same, there is a high possibility that the access point will not be able to acquire the retransmission frame again. If transmission/reception of the retransmission frame also fails, the terminal further lowers the transmission rate and transmits the retransmission frame.

Considering that retransmission control as described above is performed in the terminal and that there is a high possibility that the capture of wireless frames with a high transmission rate will fail in the monitor device, many retransmission frames with a low transmission rate will be captured. Become. If the retransmission rate is calculated based on such captured radio frames, there is a possibility that the retransmission rate cannot accurately represent the state of the radio system. In other words, depending on the environment of the wireless communication system, all captured wireless frames may be "retransmission frames". In this case, the retransmission rate is calculated as the ratio of "captured" retransmitted frames to all "captured" radio frames, so the retransmission rate is 100%.

However, in reality, there should be an initial transmission frame before the retransmission frame, and there should be a retransmission frame with a high transmission rate before the captured retransmission frame. Therefore, the result that the retransmission rate is as high as 100% is usually impossible. A sequence number is included in the header of the radio frame, and based on the sequence number, it is possible to estimate the number of initial transmission frames that could not be captured. For example, if the initial transmission frame with the sequence number "1" and the initial transmission frame with the sequence number "3" can be captured, the existence of the initial transmission frame with the sequence number "2" can be estimated. However, since the same sequence number is assigned to retransmitted frames, such an estimation cannot be performed. That is, the number of uncaptured retransmission frames cannot be grasped, and an accurate retransmission rate cannot be obtained.

In this regard, even if the technology disclosed in Non-Patent Document 3 or the like is used, an accurate retransmission rate cannot be obtained. The technology disclosed in Non-Patent Document 3 is based on the premise that state transitions are more likely to occur with less capture loss, and are inconsistent with the reality of wireless communication systems that are actually used in the field. As described above, the terminal lowers the transmission rate when retransmitting the radio frame, but how much the transmission rate is lowered depends on the terminal. For example, while there are aggressive terminals with a small reduction, there are also passive terminals that take a large reduction from the beginning. Non-Patent Document 3 does not consider such a difference in characteristics (features) for each terminal, and cannot correctly estimate the presence of a radio frame in which capture loss has occurred.

A main object of the present invention is to provide an information processing device, a wireless communication system, an information processing method, and a program that contribute to accurately estimating the existence of a wireless frame that a monitor device could not detect.

According to a first aspect of the present invention, an acquisition unit acquires a radio frame transmitted by a terminal and detected by a monitor device, and a first transmission frame among the detected radio frames is transmitted a first transition model generating unit for generating a first transition model regarding a rate for each terminal; and a second transition model regarding a transmission rate of a retransmission frame among the detected radio frames for each terminal. 2 transition model generation unit; and an estimation unit that estimates the number of lost frames among wireless frames transmitted by the terminal that cannot be detected by the monitor device using the first and second transition models; An information processing device is provided.

According to a second aspect of the present invention, a monitor device for detecting a radio frame transmitted by a terminal and an information processing device connected to the monitor device are included, wherein the information processing device detects a radio frame transmitted by the terminal. an acquisition unit that acquires a radio frame that is a frame detected by the monitor device; 1 transition model generation unit; a second transition model generation unit that generates a second transition model regarding a transmission rate of a retransmission frame among the detected radio frames for each terminal; an estimating unit that estimates, using a transition model, the number of lost frames transmitted by a terminal but not detected by the monitoring device.

According to a third aspect of the present invention, a wireless frame transmitted by a terminal and detected by a monitor device is acquired, and a first transmission rate related to a transmission rate of an initial transmission frame among the detected wireless frames is acquired. generating a transition model for each terminal, generating a second transition model regarding the transmission rate of retransmission frames among the detected radio frames for each terminal, and using the first and second transition models, the terminal and estimating the number of lost frames transmitted by the monitoring device but not detected by the monitoring device.

According to a fourth aspect of the present invention, a process for acquiring a wireless frame detected by a monitor device, which is a wireless frame transmitted by a terminal, and a transmission rate of the first transmission frame among the detected wireless frames. A process of generating a first transition model for each terminal, a process of generating a second transition model regarding a transmission rate of retransmission frames among the detected radio frames for each terminal, and the first and second transitions. A program for causing a computer to execute a process of estimating the number of lost frames transmitted by a terminal but not detected by the monitor device using the model is provided.

According to each aspect of the present invention, an information processing device, an information processing method, and a program are provided that contribute to accurately estimating the existence of a radio frame that a monitor device could not detect. It should be noted that other effects may be achieved by the present invention instead of or in addition to the above effects.

1 is a diagram for explaining an overview of an embodiment; FIG. 1 is a diagram illustrating an example of a schematic configuration of a radio communication system according to a first embodiment; FIG. 3 is a diagram illustrating an example of a processing configuration of a monitor device according to the first embodiment; FIG. It is a figure showing an example of processing composition of an evaluation device concerning a 1st embodiment. FIG. 5 is a diagram for explaining the operation of the first transition model generation unit according to the first embodiment; FIG. 10 is a diagram showing an example of an initial transmission rate transition model; 4 is a flow chart showing an example of the operation of a first transition model generation unit; FIG. 11 is a flowchart showing an example of an operation of a first transition model generation unit regarding initial transmission rate transition model generation; FIG. It is a figure for demonstrating operation|movement of the 2nd transition model production|generation part which concerns on 1st Embodiment. FIG. 4 is a diagram showing an example of a retransmission rate transition model; 9 is a flow chart showing an example of the operation of a second transition model generation unit; It is a figure which shows an example of the information stored in the memory|storage part which concerns on 1st Embodiment. FIG. 4 is a diagram for explaining the operation of a lost frame number estimator; 9 is a flow chart showing an example of the operation of a lost frame number estimator; FIG. 4 is a diagram for explaining the operation of a lost frame number estimator; FIG. 4 is a diagram for explaining the operation of a lost frame number estimator; FIG. 10 is a diagram showing an example of the transmission rate, probability and expected value of an initial transmission frame; It is a figure which shows an example of the information stored in the memory|storage part of an evaluation apparatus. 6 is a flow chart showing an example of the operation of an evaluation index generator; FIG. 11 is a flow chart showing an example of the operation of a first transition model generation unit according to the second embodiment; FIG. It is a figure which shows an example of the information stored in the memory|storage part which concerns on 2nd Embodiment. It is a figure which shows an example of the hardware constitutions of an evaluation apparatus.

First, an overview of one embodiment will be described. It should be noted that the drawing reference numerals added to this outline are added to each element for convenience as an example to aid understanding, and the description of this outline does not intend any limitation. In addition, in the present specification and drawings, elements that can be described in the same manner can be omitted from redundant description by assigning the same reference numerals.

An information processing apparatus 100 according to one embodiment includes an acquisition unit 101, a first transition model generation unit 102, a second transition model generation unit 103, and an estimation unit 104 (see FIG. 1). The acquiring unit 101 acquires a wireless frame transmitted by a terminal and detected by a monitor device. The first transition model generation unit 102 generates a first transition model regarding the transmission rate of the first transmission frame among the detected radio frames for each terminal. Second transition model generation section 103 generates a second transition model regarding the transmission rate of retransmission frames among the detected radio frames for each terminal. Using the first and second transition models, the estimation unit 104 estimates the number of lost frames transmitted by the terminal that cannot be detected by the monitor device.

The information processing apparatus 100 focuses on the fact that retransmission frame control is different for each terminal, and learns how the terminal behaves when transmitting the initial transmission frame or the retransmission frame from the radio frame detected by the monitor device. do. Specifically, a first transition model that models the probability of each transmission rate set when an initial transmission frame is transmitted, and a probability of each transmission rate that is set when a retransmission frame is transmitted are used. A modeled second transition model is generated. Since these transition models are generated for each terminal, they include features such as terminal retransmission control. The information processing apparatus 100 applies the radio frames detected by the monitor device to the above two transition models, and determines the radio frames (loss frames) that the monitor device could not detect among the radio frames assumed to be transmitted by each terminal. presume the existence of That is, since the existence of a lost frame is estimated by a transition model including features related to transmission control of each terminal, the information processing apparatus 100 can accurately estimate wireless frames that the monitor apparatus cannot detect.

Specific embodiments will be described in more detail below with reference to the drawings.

[First Embodiment]
The first embodiment will be described in more detail with reference to the drawings.

FIG. 2 is a diagram showing an example of a schematic configuration of a radio communication system according to the first embodiment. Referring to FIG. 2, the wireless communication system includes a plurality of terminals 10-1 to 10-3, an access point (AP) 20, a monitor device 30, and an evaluation device . In the following description, the terminals 10-1 to 10-3 are simply referred to as "terminal 10" unless there is a particular reason to distinguish them.

The configuration of the wireless communication system shown in FIG. 2 is an example, and is not meant to limit the number of terminals 10 or the like. For example, a wireless communication system may include at least one or more terminals 10 . Moreover, although the monitor device 30 and the evaluation device 40 are directly connected in FIG. 2, these devices may be connected via a network. Alternatively, the monitor device 30 may be installed in a field including the terminal 10 and the access point 20, and the evaluation device 40 may be installed as a server on the cloud.

The access point 20 provides the terminal 10 with a wireless connection such as a wireless LAN (Local Area Network). Terminal 10 communicates with a server (not shown) or the like on a network via access point 20 .

The monitor device 30 is an external device (monitor terminal; capture device) that detects (or collects, acquires, or captures) radio frames transmitted and received between the terminal 10 and the access point 20 . The monitoring device 30 is placed near the access point 20 where the most useful information is assumed to be obtained in evaluating the state of the wireless communication system. For example, when the access point 20 is placed on the ceiling in a space such as a warehouse, the monitor device 30 can efficiently collect useful information by placing it on the floor directly below the access point 20 placed on the ceiling. can do.

In the following description, among wireless frames transmitted and received between the terminal 10 and the access point 20, a wireless frame successfully detected (captured) by the monitor device 30 is referred to as a "capture frame". Of the radio frames transmitted and received between the terminal 10 and the access point 20, a radio frame that the monitor device 30 fails to detect (capture) (capture lost radio frame) is referred to as a "lost frame".

A radio frame that does not include a retransmission flag is referred to as an "initial transmission frame", and the transmission rate of the initial transmission frame is referred to as an "initial transmission rate". Similarly, a radio frame including a retransmission flag is referred to as "retransmission frame", and the transmission rate of the retransmission frame is referred to as "retransmission rate".

In the disclosure of the present application, data frames, management frames, and control frames are collectively referred to as radio frames unless otherwise specified.

The evaluation device 40 is a device (information processing device) that calculates an index for evaluating the state of the wireless communication system. The evaluation device 40 corresponds to the information processing device 100 described above. For example, the evaluation device 40 calculates a “retransmission rate” indicating the ratio of retransmission frames in radio frames transmitted by each terminal 10 included in the radio communication system. Details of retransmission rate calculation will be described later.

[Overview of system operation]
First, with reference to FIG. 2, an outline of the operation of the wireless communication system according to the first embodiment will be described.

Terminal 10 communicates with a server (not shown) or the like on a network via access point 20 . The monitor device 30 detects (captures) radio frames transmitted and received between the terminal 10 and the access point 20 . The monitor device 30 transmits the detected radio frame to the evaluation device 40 .

The evaluation device 40 uses the radio frames acquired from the monitor device 30 to calculate an index for evaluating the state of the radio communication system. For example, the evaluation device 40 calculates the retransmission rate for each terminal 10 as an evaluation index. For example, if the retransmission rate is too high, it is suspected that a failure has occurred in the wireless communication system, which triggers an administrator or the like to investigate the failure.

The operating modes of evaluation device 40 include two operating modes.

The first operation mode is a learning mode in which wireless frames acquired from the monitor device 30 are used as "learning data" to learn (model) the behavior of each terminal 10 present in the field.

The second operation mode is an evaluation mode in which radio frames obtained from the monitor device 30 are used as "evaluation data" to calculate an evaluation index (retransmission rate) for each terminal 10. FIG.

Next, details of each device included in the wireless communication system will be described.

[Monitor device]
FIG. 3 is a diagram showing an example of a processing configuration (processing modules) of the monitor device 30 according to the first embodiment. Referring to FIG. 3 , the monitor device 30 includes a communication control section 201 and a radio frame acquisition section 202 .

The communication control unit 201 controls communication with another device (evaluation device 40).

The radio frame acquisition unit 202 is connected to the antenna 211 and captures (acquires) radio frames transmitted and received between the terminal 10 and the access point 20 .

The wireless frame acquisition unit 202 transmits the acquired wireless frame (capture frame) and accompanying information to the evaluation device 40 . The wireless frame acquisition unit 202 may transmit the acquired wireless frame or the like to the evaluation device 40 each time it acquires a wireless frame, or may collectively transmit a predetermined amount of wireless frames or the like to the evaluation device 40 . .

The radio frame acquisition unit 202 calculates the radio field intensity (RSSI: Received Signal Strength Indication) and transmission rate when the radio frame is acquired, and transmits this information to the evaluation device 40 as accompanying information of the radio frame.

Alternatively, the radio frame acquisition unit 202 reads out information such as a source MAC (Media Access Control) address, a destination MAC address, a sequence number, a retransmission flag, etc. from the header of the radio frame, associates these information with the accompanying information, and evaluates them. It may be sent to device 40 .

In the first embodiment, the following description will be made on the assumption that the radio frame acquisition unit 202 transmits the source MAC address, radio wave intensity, etc. to the evaluation device 40 . The statement that the monitor device 30 transmits a wireless frame (capture frame) to the evaluation device 40 can also be read as that the monitor device 30 transmits information about the wireless frame (source MAC address, radio field intensity, etc.) to the evaluation device 40. .

[Evaluation device]
FIG. 4 is a diagram showing an example of a processing configuration (processing modules) of the evaluation device 40 according to the first embodiment. Referring to FIG. 4, the evaluation device 40 includes a communication control unit 301, a first transition model generation unit 302, a second transition model generation unit 303, a lost frame number estimation unit 304, and an evaluation index generation unit 305. , and a storage unit 306 .

The first transition model generation unit 302 and the second transition model generation unit 303 are modules that mainly operate in the learning mode. The lost frame number estimation unit 304 and the evaluation index generation unit 305 are modules that mainly operate in the evaluation mode.

Note that the monitor device 30 transmits the acquired radio frames to the evaluation device 40 regardless of the operation mode of the evaluation device 40 . Therefore, since the evaluation device 40 can handle the radio frames acquired from the monitor device 30 as "learning data" or as "evaluation data", two operation modes (learning mode and evaluation mode) can be performed in parallel. You can run it by

The communication control unit 301 controls communication with another device (monitor device 30). The communication control unit 301 includes a function as an acquisition unit that acquires radio frames detected by the monitor device 30 .

The first transition model generation unit 302 generates a transition model regarding the transmission rate of the initial transmission frame for each terminal 10 within the field. In the following description, the transition model generated by the first transition model generation unit 302 is referred to as "initial transmission rate transition model".

The initial transmission rate transition model is a probability model that models the probability of each transmission rate that can be set for transmission of the initial transmission frame when the terminal 10 transmits the initial transmission frame. For example, according to the initial transmission rate transition model, when the terminal 10 transmits an initial transmission frame after transmitting a retransmission frame, or when a different initial transmission frame is transmitted after transmitting the initial transmission frame, the subsequently transmitted initial transmission frame A probability can be calculated for each transmission rate set for the transmission of .

In the first embodiment, a case where a Markov model is used as the initial transmission rate transition model will be described.

The first transition model generation unit 302 generates an initial transmission rate transition model using radio frames (capture frames) accumulated in the learning mode as learning data. Specifically, the first transition model generation unit 302 extracts the radio frame of the terminal 10 for which the transition model is to be generated from the learning data.

Next, the first transition model generation unit 302 extracts a pair of radio frames before and after the sequence number of the radio frame is changed by "1". For example, let us consider a case where learning data for generating the initial transmission rate transition model is data as shown in FIG. 5, and the initial transmission rate transition model for the terminal 10-1 is generated. In this case, pairs of radio frames with sequence fields colored gray in FIG. 5 are extracted.

As shown in FIG. 5, if the sequence number is incremented, the transition may be from the retransmission frame to the initial transmission frame, or from the initial transmission frame to the initial transmission frame.

Note that if the sequence number is not a sequential number, it is not extracted as a wireless frame pair. For example, if the sequence number changes from "3" to "5", the radio frames with these sequence numbers are not extracted as the pair.

The first transition model generation unit 302 constructs a Markov model using the extracted pair of radio frames. The constructed Markov model becomes the initial transmission rate transition model for each terminal. For example, an initial transmission rate transition model as shown in FIG. 6 is generated.

Referring to FIG. 6, if the transmission rate before transmitting the initial transmission frame is "10 Mbps (megabytes per second; hereinafter the same)", the transmission rate of the initial transmission frame is "10 Mbps" with a probability of 46%. It can be seen that the transmission rate of the first transmission frame is "54 Mpbs" with a probability of %.

The operation of the first transition model generation unit 302 is summarized as shown in the flowchart of FIG.

The first transition model generation unit 302 extracts the radio frame of the terminal 10 to be the target of transition model generation (radio frame in which the terminal is set as the transmission source MAC address) from the learning data (step S101).

The first transition model generation unit 302 further extracts pairs of radio frames having consecutive sequence numbers from the extracted radio frames (step S102).

The first transition model generation unit 302 generates an initial transmission rate transition model using the extracted wireless frame pair (step S103).

The operation of the first transition model generation unit 302 regarding the generation of the initial transmission rate transition model is as shown in the flowchart of FIG.

The first transition model generation unit 302 sets the transmission rate of the radio frame that is transmitted first among the two radio frames forming the radio frame pair to β, and sets the transmission rate of the radio frame that is transmitted later to γ (step S111). β and γ are Markov model nodes. For example, in the example of FIG. 5, the transmission rate of the radio frame "36 Mbps" on the third line is set to β, and the transmission rate of the radio frame "54 Mbps" on the fourth line is set to γ.

The first transition model generation unit 302 defines an edge from β to γ, and sets the weight of the edge to "1". Alternatively, if the edge already exists, the first transition model generation unit 302 adds "1" to the weight of the edge.

The first transition model generation unit 302 repeats the node setting and edge weight setting (addition to weight) for all wireless frame pairs.

The first transition model generation unit 302 adds all edge weights directed from a specific node to other nodes (including its own node) to calculate a total edge weight. After that, the first transition model generation unit 302 divides the weight of each edge by the total edge weight to calculate the edge transition probability (step S113).

The first transition model generation unit 302 executes the above edge transition probability calculations for all nodes, and constructs a first transmission rate transition model consisting of nodes, edges, and transition probabilities.

Next, the second transition model generation unit 303 will be described.

The second transition model generating section 303 generates a transition model regarding the transmission rate of retransmission frames. In the following description, the transition model generated by second transition model generating section 303 is referred to as "retransmission rate transition model".

The retransmission rate transition model is a probability model that models the probability of each transmission rate that can be set for transmission of a retransmission frame when the terminal 10 transmits the retransmission frame. For example, according to the retransmission rate transition model, when the terminal 10 transmits a retransmission frame after transmitting the initial transmission frame, or when the terminal 10 transmits a retransmission frame after transmitting the retransmission frame, each transmission rate set for the retransmission frame can be calculated.

Second transition model generation section 303 generates a retransmission rate transition model using radio frames accumulated in the learning mode as learning data. Specifically, the second transition model generation unit 303 extracts the radio frame of the terminal 10 for which the transition model is to be generated from the learning data.

Next, second transition model generating section 303 extracts a pair of a radio frame indicating retransmission and a radio frame transmitted immediately before the radio frame indicating retransmission from among the extracted radio frames.

For example, let us consider a case where learning data for generating a retransmission rate transition model is data as shown in FIG. 9 and a retransmission rate transition model for terminal 10-1 is generated. In this case, frame pairs containing radio frames with retransmission flag fields colored gray in FIG. 9 are extracted. For example, as shown in FIG. 9, a pair of radio frames on the first and second lines, a pair of radio frames on the second and third lines, and the like are extracted.

The second transition model generation unit 303 constructs a Markov model using the above-extracted pairs of radio frames. The constructed Markov model becomes the retransmission rate transition model for each terminal. For example, a retransmission rate transition model as shown in FIG. 10 is generated.

Referring to FIG. 10, if the transmission rate before transmitting the retransmission frame is "10 Mbps", the retransmission frame with the transmission rate set to "10 Mbps" will be transmitted with a probability of 33%. Also, it can be seen that the retransmission frame with the transmission rate set to "1.0 Mpbs" is transmitted with a probability of 67%.

The operation of the second transition model generation unit 303 is summarized as shown in the flowchart of FIG.

The second transition model generation unit 303 extracts the wireless frame of the terminal 10 (the wireless frame in which the terminal is set as the transmission source MAC address) for which the transition model is to be generated from the learning data (step S201).

The second transition model generation unit 303 further extracts a pair of a radio frame indicating retransmission and a radio frame transmitted immediately before the radio frame indicating retransmission from the extracted radio frames (step S202).

The second transition model generation unit 303 generates a retransmission rate transition model using the extracted wireless frame pair (step S203).

The basic operation when the second transition model generation unit 303 generates the retransmission rate transition model is assumed to be the same as the operation when the first transition model generation unit 302 generates the initial transmission rate transition model. Therefore, the explanation is omitted.

As described above, first transition model generation section 302 and second transition model generation section 303 each generate an initial transmission rate transition model and a retransmission rate transition model for each terminal 10 . The generated initial transmission rate transition model and retransmission rate transition model are stored in the storage unit 306 (see FIG. 12).

Next, the lost frame number estimation unit 304 will be described.

The lost frame number estimation unit 304 estimates the number of wireless frames (lost frames) assumed to be lost by the monitor device 30 based on the wireless frames (capture frames) acquired from the monitor device 30 in the evaluation mode.

Using the initial transmission rate transition model and the retransmission rate transition model generated in the learning mode, the lost frame number estimating unit 304 detects wireless frames transmitted by the terminal 10 that the monitor device 30 cannot detect (capture). Estimate the number of frames (lost frames). For example, let us consider a case where radio frames as shown in FIG. Of the radio frames shown in FIG. 13, those actually input to the evaluation device 40 are radio frames (white radio frames) other than the radio frames colored in gray.

Lost frame number estimating section 304 estimates the number of wireless frames (lost frames; wireless frames colored in gray) that could not be detected by monitor device 30 from white wireless frames (capture frames) shown in FIG. More precisely, the lost frame number estimating section 304 estimates the number of lost frames for the retransmission frames among the radio frames that the monitor device 30 could not detect, using the above-described transition model. On the other hand, regarding the first transmission frame, it is estimated from the sequence number that the first transmission frame could not be detected.

Lost frame number estimation section 304 estimates the number of lost frames for each sequence number. In the example of FIG. 13, four radio frames with a sequence number of "1", three radio frames with a sequence number of "2", and two radio frames with a sequence number of "3" are used as one unit of lost frames. Estimate the number of That is, the lost frame number estimating section 304 estimates the number of lost frames in units of radio frames having the same sequence number among the radio frames detected by the monitor device 30 .

In the following description, the unit (radio frames having the same sequence number) used by the lost frame number estimating section 304 to estimate the number of lost frames is referred to as a loss estimation unit or simply an estimation unit. Also, a radio frame belonging to a loss estimation unit is referred to as a "loss estimation radio frame group".

Lost frame number estimation section 304 does not estimate the number of lost frames for a loss estimation unit in which an initial transmission frame exists. The fact that the monitor device 30 can detect (capture) the initial transmission frame is based on the assumption that retransmission frames whose transmission rate is lower than that of the initial transmission frame can also be detected. That is, the lost frame number estimating unit 304 estimates the number of lost frames among the radio frames detected by the monitor device 30 with respect to the radio frames having the sequence numbers in which the first transmission frame does not exist.

In the example of FIG. 13, the number of lost frames is estimated for the radio frame having the sequence number "2" in which the initial transmission frame is not detected. The operation of the lost frame number estimation unit 304 will be described below with reference to FIG.

The loss frame number estimation unit 304 determines whether or not an initial transmission frame exists in the estimated loss radio frame group (step S301).

If there is an initial transmission frame (step S301, Yes branch), the lost frame number estimation unit 304 terminates the process.

If there is no initial transmission frame (step S301, No branch), the loss frame number estimation unit 304 acquires the transmission rate of the radio frame transmitted immediately before the estimated loss radio frame group (step S302). For example, in the example of FIG. 13, the loss frame number estimation unit 304 acquires the transmission rate of "20 Mbps" of the radio frame transmitted immediately before the loss estimated radio frame group with the sequence number of "2".

The lost frame number estimation unit 304 inputs the acquired transmission rate to the initial transmission rate transition model (step S303).

By inputting the transmission rate into the initial transmission rate transition model, the transition probability for each initial transmission rate can be obtained (see FIG. 15, for example). In FIG. 15, the transition probability to each initial transmission rate when the transmission rate of the radio frame before transmitting the initial transmission frame is 20 Mbps is written together with the initial transmission rate in parentheses. In this way, the lost frame number estimating section 304 calculates the transmission rate of the radio frame transmitted immediately before the retransmission frame for which the corresponding initial transmission frame does not exist among the radio frames detected by the monitor device 30 according to the initial transmission rate transition model. to enter. As a result, the probability of transition from the transmission rate of the radio frame transmitted immediately before to each initial transmission rate is obtained.

The loss frame number estimation unit 304 determines whether or not a retransmission frame exists in the estimated loss radio frame group (step S304).

If the retransmission frame exists (step S304, Yes branch), the loss frame number estimation unit 304 acquires the transmission rate of the first retransmission frame (the first detected retransmission frame) in the estimated loss radio frame group. (Step S305). For example, in the example of FIG. 13, the lost frame number estimation unit 304 acquires the transmission rate of 10 Mbps of the first detected radio frame in the radio frame group with the sequence number "2".

If the retransmission frame does not exist (step S304, No branch), the loss frame number estimation unit 304 acquires the transmission rate of the radio frame transmitted immediately before the estimated loss radio frame group (step S306). If all the radio frames with the sequence number “2” shown in FIG. 13 are not detected, the lost frame number estimating unit 304 detects the last transmitted radio frame with the sequence number “1”. Acquire a transmission rate of 20 Mbps for radio frames.

In the following description, the transmission rate of the radio frames acquired in step S305 or step S306 is referred to as "terminating transmission rate".

The lost frame number estimator 304 calculates an expected value for the number of retransmitted frames from each possible initial transmission rate to the terminal transmission rate (step S307). Specifically, the lost frame number estimating section 304 selects one initial transmission rate from the initial transmission rates of initial transmission frames that can be taken in the system, and retransmits the selected initial transmission rate and the termination transmission rate. Enter the model.

By inputting the termination transmission rate and the initial transmission rate into the retransmission rate transition model, an expected value for the number of retransmission frames with capture loss from the initial transmission rate to the termination transmission rate can be obtained. For example, part of the retransmission rate transition model is as shown in FIG. 16, and the above expected values when "40 Mbps" as the initial transmission rate and "10 Mbps" as the termination transmission rate are input to the retransmission rate transition model are as follows. can be calculated as

According to FIG. 16, the probability of transition from transmission of the initial transmission frame (40 Mbps) to transmission of the retransmission frame (10 Mbps) is 67%. In this case, since there are no retransmission frames with capture loss, the expected value of the number of retransmission frames with capture loss is 0.67×0=0.

The probability of transitioning from transmission of an initial transmission frame with an initial transmission rate of 40 Mbps to transmission of a retransmission frame with a retransmission rate of 40 Mbps is 33%. In this case, after one retransmission occurs, a retransmission frame whose transmission rate is set to 10 Mbps is transmitted with a probability of 67%. x1=0.22.

Similarly, the probability of transitioning from a retransmission frame with a retransmission rate of 40 Mbps to transmission of a retransmission frame with a retransmission rate of 40 Mbps is 0.33×0.33. In this case, after two retransmissions, retransmission frames with the transmission rate set to 10 Mbps are transmitted with a probability of 67%, so the expected value of the number of retransmission frames with capture loss is 0.33×0.33×0. .67×2=0.15.

Since the number of times of retransmission at the same transmission rate is predetermined in the wireless communication standard, the lost frame number estimation unit 304 calculates the expected value corresponding to the predetermined number of times, and sums the is calculated as the expected value for the final number of retransmission frames with capture loss.

The calculation of the expected value E regarding the number of retransmission frames in which the capture loss occurred by the lost frame number estimating section 304 is expressed as the following equation (1).

In equation (1), _Pf is the probability of transition from the initial transmission rate to the termination transmission rate, and _Pr is the probability that the retransmission frame will be transmitted at the same transmission rate as the initial transmission rate. Also, a indicates the number of times the radio frame is transmitted with the probability of _Pr . The initial value of a is 0. K is the maximum number of retransmissions. Also, "*" is a multiplication operator.

In the example of FIG. 16, for ease of understanding, the case where the "initial transmission rate" is selected as the start node and the "termination transmission rate" is selected as the end node is illustrated, but there are intermediate nodes. The expected value can also be calculated in the same way.

Lost frame number estimating section 304 repeats the above calculation for the possible initial transmission frame transmission rates in the system, and calculates the number of retransmission frames that would have been transmitted from each initial transmission rate to the final transmission rate. Calculate the expected value (number of retransmissions) of In this way, the lost frame number estimating section 304 inputs the transmission rate of retransmitted frames for which no initial transmission frame corresponding to each initial transmission rate exists to the retransmission rate transition model. As a result, an expected value is calculated for the number of retransmission frames with capture loss when each initial transmission rate reaches the transmission rate of a retransmission frame for which there is no corresponding initial transmission frame.

For example, the relationship shown in FIG. 17 is obtained by summarizing the probability of transition to each initial transmission rate shown in FIG. 15 and the expected value for the number of retransmission frames with capture loss from the initial transmission rate to the termination transmission rate.

The lost frame number estimating section 304 estimates the number of lost frames based on the obtained probability of transition to each initial transmission rate and the calculated expected value. Specifically, the lost frame number estimation unit 304 multiplies the probability of transition to the transmission rate of the first transmission frame by the corresponding expected value, and totals the multiplication results to calculate the estimated number of lost frames. (Step S308).

Lost frame number estimating section 304 repeats the above-described processing, estimates the number of lost frames when the initial transmission frame is not detected (captured), and stores the result in storage section 306 . At that time, the lost frame number estimation unit 304 determines the sequence number, the number of radio frames detected for each sequence number, the presence or absence of the first transmission frame corresponding to the sequence number, and the estimated number of lost frames when there is no first transmission frame. are collectively stored in the storage unit 306 . For example, information as shown in FIG. 18 is stored in the storage unit 306 .

Evaluation index generating section 305 generates an index indicating the state of the wireless communication network based on the number of lost frames estimated by lost frame number estimating section 304 . In the first embodiment, the evaluation index generator 305 calculates the retransmission rate of radio frames.

The evaluation index generator 305 calculates the retransmission rate of radio frames using information as shown in FIG. Specifically, the evaluation index generator 305 calculates the retransmission rate _RTr of the radio frame according to the following equation (2).

In equation (2), TN _f indicates the total number of initial transmission frames (total number of initial transmission frames). TN _r indicates the total number of transmissions of retransmission frames (total number of retransmission frames).

The operation of the evaluation index generator 305 will be described below with reference to FIG.

The evaluation index generation unit 305 initializes parameters necessary for generating evaluation indexes (step S401). Specifically, the evaluation index generator 305 initializes the total number of initial transmission frames and the total number of retransmission frames.

The evaluation index generation unit 305 acquires the range of sequence numbers for which the retransmission rate is calculated (step S402). For example, the evaluation index generation unit 305 obtains the minimum and maximum values of the sequence numbers included in the evaluation data of the terminal 10 for which the retransmission rate is to be calculated, and uses them as the range of the sequence numbers. In the example of FIG. 13, the sequence numbers range from "1" to "5".

The evaluation index generation unit 305 sets the minimum sequence number as the target sequence number for index calculation (step S403).

The evaluation index generator 305 adds "1" to the total number of initial transmission frames (increments the total number of initial transmission frames; step S404).

The evaluation index generation unit 305 determines whether or not the target sequence includes an initial transmission frame (step S405).

If there is an initial transmission frame (step S405, Yes branch), the evaluation index generation unit 305 adds the number of retransmission frames of the target sequence to the total number of retransmission frames. For example, in the example of FIG. 18, if the sequence number "1" is the target sequence, the target sequence includes the initial transmission frame, so the number of retransmission frames "3" is added to the total number of retransmission frames.

If there is no initial transmission frame (step S405, No branch), the evaluation index generation unit 305 adds the number of retransmission frames of the target sequence and the estimated value of lost frames to the total number of retransmission frames. For example, in the example of FIG. 18, if the sequence number “2” is the target sequence, the target sequence does not include the first transmission frame, so the number of retransmission frames “3” and the estimated value of lost frames “2” is added to the total number of retransmitted frames.

After incrementing the number of the target sequence, the evaluation index generation unit 305 determines whether or not there is a remaining target sequence that has not been processed in steps S406 and S407 (step S408).

If there is a remaining target sequence (step S408, Yes branch), the evaluation index generation unit 305 returns to step S404 and continues the processing.

If there is no remaining target sequence (step S408, No branch), the evaluation index generation unit 305 calculates the retransmission rate (step S409). Specifically, the evaluation index generation unit 305 inputs the calculated total number of initial transmission frames and total number of retransmission frames to each parameter of the above equation (2), and calculates the retransmission rate.

As described above, the evaluation device 40 according to the first embodiment generates, for each terminal, a transition model (initial transmission rate transition model, retransmission rate transition model) indicating characteristics of transmission control of radio frames of the terminal. . After that, if there is a retransmission frame without a corresponding initial transmission frame among the wireless frames detected by the monitoring device 30, the evaluation device 40 determines whether the retransmission frame without the corresponding initial transmission frame is transmitted. A retransmission frame assumed to have been transmitted by the terminal 10 is estimated by the above transition model. More specifically, the evaluation device 40 evaluates the probability that the transmission rate of the initial transmission frame that would have been transmitted after the retransmission frame that was transmitted immediately before the retransmission frame that does not have the corresponding initial transmission frame. Derived from the rate transition model. After deriving the probabilities that each initial transmission rate can take, the evaluation device 40 determines the probability that the initial transmission rate has been transmitted from the transmission of the initial transmission frame to the retransmission frame without the corresponding initial transmission frame. A probability can be derived for the number of deaf retransmission frames. The evaluation device 40 regards the probability and the state transition (state transition of the retransmission rate) in the retransmission rate transition model as the transmission of the retransmission frame, and multiplies the probability by the number of assumed state transitions to retransmit the frame from the first transmission. Calculate the expected value for the retransmitted frames up to the frame. The expected value can be regarded as the number of retransmission frames that the monitor device 30 could not detect.

As a result, the evaluation device 40 can estimate the number of lost frames with high accuracy while taking into consideration the characteristics of each terminal 10, and thus can calculate a highly reliable evaluation index. Specifically, even if the transmission rate is low, the retransmission rate is calculated in consideration of undetected radio frames, so that calculation of an excessively high retransmission rate can be prevented.

[Second embodiment]
Next, a second embodiment will be described in detail with reference to the drawings.

In the first embodiment, state transition models (initial transmission rate transition model, retransmission rate transition model) are generated for each terminal 10, and these transition models are used to estimate the number of lost frames. Here, as a result of intensive studies by the inventors, it has been found that the behavior of the terminal 10 varies depending on the radio wave intensity. In other words, it was found that the operation of each terminal 10 when transmitting a retransmission frame differs when the radio wave intensity differs.

For example, even for the same terminal 10, when the radio wave intensity is high, the retransmission frame is transmitted while lowering the transmission rate in small increments. It has been found that the behavior of Also, regarding the transmission of the first transmission frame, it was found that when the radio field strength is high, the transmission rate is greatly increased upon successful retransmission, whereas when the radio field strength is low, the transmission rate is not greatly increased upon successful retransmission. there is

Considering these facts, it can be said that the number of lost frames can be estimated with higher accuracy by generating a transition model for each radio wave intensity and using it for estimating the number of lost frames. In the second embodiment, generation of a transition model for each terminal and each radio wave intensity will be described.

In addition, in the first and second embodiments, the system configuration and the internal configuration of the evaluation device 40 can be the same, so the description of the drawings corresponding to FIG. 2, FIG. 4, etc. will be omitted.

The following description focuses on the differences between the first and second embodiments.

The first transition model generation unit 302 according to the second embodiment further extracts a wireless frame pair having a radio wave intensity higher than a predetermined radio wave intensity from the wireless frame pairs for each terminal 10 extracted from the learning data. . For example, the possible range of radio wave intensity is (0 dBm to -60 dBm), and the initial transmission rate Consider the case where a transition model is generated. Note that the division of the radio wave intensity range is an example, and it is needless to say that the division may be made more roughly or more finely. Also, the widths of the divided radio wave intensity ranges may be the same or may be different. For example, divisions such as 0 dBm to -10 dBm, -10 dBm to -30 dBm, and -30 dBm to -60 dBm may be used.

In the above example of dividing into three equal parts, the first transition model generation unit 302 extracts radio frames having a radio field strength of 0 dBm or more, and extracts the initial transmission rate transition model corresponding to the radio field strength range (0 dBm to -20 dBm) to generate Further, the first transition model generation unit 302 extracts radio frames having radio field strength of -20 dBm or more, and generates an initial transmission rate transition model corresponding to the radio field strength range (-20 dBm to -40 dBm). Similarly, the first transition model generation unit 302 extracts radio frames having radio field strength of -40 dBm or more, and generates an initial transmission rate transition model corresponding to the radio field strength range (-40 dBm to -60 dBm). In this way, the first transition model generation unit 302 extracts radio frames having radio field strength ranges equal to or greater than the upper limits of the divided radio field strength ranges (0 dB, −20 dB, and −40 dB in the above example), Generating an initial rate transition model corresponding to the range.

The operation of the first transition model generation unit 302 according to the second embodiment is summarized as shown in the flowchart of FIG. In the flowchart shown in FIG. 7 and the flowchart shown in FIG. 20, the same step names are given to the steps having the same processing, and the description thereof is omitted.

As shown in FIG. 20, the first transition model generation unit 302 extracts a pair of radio frames having a radio field intensity equal to or greater than a predetermined radio field intensity (step S102a), and uses the extracted radio frame pair for the first time. A transport rate transition model is constructed (step S103).

Similarly to the first transition model generation unit 302, the second transition model generation unit 303 also generates a retransmission rate transition model for each terminal 10 and for each radio wave intensity. Information as shown in FIG. 21 is generated by the two transition model generation units according to the second embodiment and stored in the storage unit 306 .

The lost frame number estimation unit 304 according to the second embodiment also estimates the number of lost frames for each radio wave intensity. Specifically, the lost frame number estimation unit 304 selects the initial transmission rate transition model used in step S303 of FIG. 14 and the retransmission rate transition model used in step S307 from the transition models generated for each radio field strength to choose from.

For example, the lost frame number estimating unit 304 calculates the average value of the radio field intensity of the wireless frames included in the evaluation data of the terminal 10 for which the number of lost frames is calculated.

The lost frame number estimation unit 304 selects the transition model to which the average value belongs, and uses it as the transition model used in steps S303 and S307 of FIG. For example, as shown in FIG. 21, a transition model is generated for each of three levels of radio wave intensity. A transition model is selected.

A transition model may be selected based on the mode or median value of radio field intensity of radio frames instead of the average value of the transmission rate of radio frames calculated by the lost frame number estimating unit 304 . Alternatively, the lost frame number estimation unit 304 may calculate a weighted average of radio frames and select a transition model according to the weighted average. For example, the lost frame number estimator 304 may give a small weight to a radio frame whose transmission time is old and a large weight to a radio frame whose transmission time is new, and calculate a weighted average.

As described above, in the second embodiment, the initial transmission rate transition model and the retransmission rate transition model are generated for each terminal 10 and for each radio wave intensity. At that time, the evaluation device 40 selects radio frames having a predetermined radio wave intensity or more to generate a transition model. By generating a transition model using radio frames with a radio wave intensity equal to or greater than this predetermined radio wave intensity, the number of lost frames is calculated to be relatively high. In other words, the terminal 10 tends to retransmit radio frames more frequently when the transmission rate is high, and less times when the transmission rate is low, although there is a difference in degree. Therefore, when the transition model is generated using the radio field strength of a predetermined range (eg, -40 dBm or more) without dividing the radio field strength of the radio frame into a predetermined range (eg, -20 dBm to -40 dBm), the generated transition model The probabilities and expectations for the transmission of retransmitted frames obtained from the transition model are higher than with bounded ranges. Therefore, it is assumed that the number of lost frames estimated from the transition model according to the second embodiment is greater than the true value. If the retransmission rate is calculated using the estimated lost frames, the retransmission rate will be calculated to be high. Here, one of the purposes of the evaluation device 40 is to detect failures in wireless communication networks, and false positives are more problematic than false negatives in failure detection. Therefore, the higher calculated retransmission rate meets the purpose of the evaluation device 40 . That is, in general, when a failure is detected, the adverse effect of judging that the failure is normal because the failure cannot be detected even though the failure actually occurs is more harmful when the failure does not actually occur. It far outweighs the detrimental effects of erroneously determining that a failure has occurred.

Next, the hardware of each device that constitutes the wireless communication system will be described. FIG. 22 is a diagram showing an example of the hardware configuration of the evaluation device 40. As shown in FIG.

The evaluation device 40 can be configured by an information processing device (so-called computer), and has a configuration illustrated in FIG. 22 . For example, the evaluation device 40 includes a processor 311, a memory 312, an input/output interface 313, a communication interface 314, and the like. Components such as the processor 311 are connected by an internal bus or the like and configured to be able to communicate with each other.

However, the configuration shown in FIG. 22 is not meant to limit the hardware configuration of the evaluation device 40 . The evaluation device 40 may include hardware (not shown) and may not include the input/output interface 313 as necessary. Also, the number of processors 311 and the like included in the evaluation device 40 is not limited to the example shown in FIG.

The processor 311 is, for example, a programmable device such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), DSP (Digital Signal Processor). Alternatively, the processor 311 may be a device such as an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or the like. The processor 311 executes various programs including an operating system (OS).

The memory 312 is RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or the like. The memory 312 stores an OS program, application programs, and various data.

The input/output interface 313 is an interface for a display device and an input device (not shown). The display device is, for example, a liquid crystal display. The input device is, for example, a device such as a keyboard or mouse that receives user operations.

The communication interface 314 is a circuit, module, etc. that communicates with other devices. For example, the communication interface 314 includes a NIC (Network Interface Card) or the like.

Functions of the evaluation device 40 are realized by various processing modules. The processing module is implemented by the processor 311 executing a program stored in the memory 312, for example. Also, the program can be recorded in a computer-readable storage medium. The storage medium can be non-transitory such as semiconductor memory, hard disk, magnetic recording medium, optical recording medium, and the like. That is, the present invention can also be embodied as a computer program product. Also, the program can be downloaded via a network or updated using a storage medium storing the program. Furthermore, the processing module may be realized by a semiconductor chip.

Note that the monitor device 30 and the like can also be configured by an information processing device like the evaluation device 40, and the basic hardware configuration thereof is the same as that of the evaluation device 40, so a description thereof will be omitted.

[Modification]
Note that the configuration, operation, and the like of the wireless communication system described in the above embodiment are examples, and are not intended to limit the configuration and the like of the system. For example, although one monitor device 30 is illustrated in FIG. 2, a plurality of monitor devices 30 may be included in the system.

In the above embodiment, the evaluation device 40 has been described as a device having a function of generating a transition model and a function of generating an evaluation index, but these functions may be realized by different devices. Alternatively, the function of generating the evaluation index of the evaluation device 40 may be implemented in the monitor device 30 .

In the above embodiment, the case where the evaluation device 40 calculates the expected value and the like using the transition model each time when estimating the number of lost frames has been described. The results may be stored in evaluation device 40 . That is, since the number of nodes of each transition model and their combinations are finite, it is possible to perform calculations for each combination in advance. Also, the processing load related to the retransmission rate is reduced by executing calculation of the transition model in advance. As a result, it is also possible for the monitor device 30 placed in the field to calculate the retransmission rate.

In the above embodiment, the initial transmission rate transition model and the retransmission frame transition model are generated by the Markov model, but machine learning such as AI (Artificial Intelligence) may be used to generate a learning model corresponding to the above transition model. .

In the above embodiment, when estimating the number of lost frames, if the retransmission frame to be estimated cannot be detected (step S304 in FIG. 14, No branch), the transmission rate of the radio frame transmitted immediately before is set as the termination transmission rate. ing. However, instead of the transmission rate of the radio frame transmitted immediately before, the lowest transmission rate (for example, 1 Mbps) in the system may be set as the termination transmission rate.

Although the retransmission rate is calculated as an index for evaluating the state of the communication network in the above embodiment, an index other than the retransmission rate may be calculated. For example, the evaluation device 40 may calculate the "band occupation rate" as an evaluation index. A band occupation rate can be calculated as a band occupation time per unit time. The evaluation device 40 can calculate the band occupation time using a transmission rate transition model. For example, assume that the transmission rate of the initial transmission frame is 5.5 Mbps and the transmission rate of the retransmission frame is 1 Mbps. It is also assumed that the probability of transition from the transmission of the initial transmission frame to the transmission of the retransmission frame is 67%, and the probability of retransmission at a transmission rate of 5.5 Mbps is 33%. In this case, the probability that the retransmission frame (1 Mbps) is transmitted from the initial transmission frame (5.5 Mbps) is 0.67. Next, the probability of transmitting an initial transmission frame (5.5 Mbps), a retransmission frame (5.5 Mbps), and a retransmission frame (1 Mbps) is 0.33×0.67. By such calculation, the probability for each number of retransmissions can be obtained. When the probability is obtained, the expected value of the time required to transmit the radio frame can be calculated from the frame transmission time determined by the transmission rate. For example, consider a case where the transmission time of 5.5 Mbps is 50 μs and the transmission time of 1 Mpbs is 250 μs. In this case, the bandwidth occupation time is calculated by a calculation of 0.67*(50+250)+0.33*0.67*(50+50+250)+. For example, if the unit time is 60 seconds and the bandwidth occupation time obtained by the above calculation is 50 seconds, the bandwidth occupation ratio can be calculated as 50/60.

Some or all of the above embodiments may also be described in the following additional remarks, but are not limited to the following.
[Appendix 1]
an acquisition unit (101, 301) for acquiring a radio frame transmitted by a terminal (10) and detected by a monitor device (30);
a first transition model generation unit (102, 302) for generating a first transition model regarding a transmission rate of the first transmission frame among the detected radio frames for each terminal (10);
a second transition model generation unit (103, 303) for generating a second transition model regarding a transmission rate of a retransmission frame among the detected radio frames for each terminal (10);
An estimating unit (104, 304) for estimating the number of lost frames transmitted by the terminal (10) but not detected by the monitoring device (30) using the first and second transition models. )and,
An information processing device (100, 40) comprising:
[Appendix 2]
1, wherein the first transition model is a probability model that models the probability of each transmission rate that can be set for transmission of the initial transmission frame when the terminal (10) transmits the initial transmission frame. information processing device (100, 40).
[Appendix 3]
The information according to appendix 2, wherein the second transition model is a probability model that models the probability of each transmission rate that can be set for transmission of the retransmission frame when the terminal (10) transmits the retransmission frame. a processor (100, 40);
[Appendix 4]
The estimating unit (104, 304) estimates the number of lost frames with respect to a radio frame having a sequence number in which an initial transmission frame does not exist among the radio frames detected by the monitoring device (30). 4. The information processing device (100, 40) according to any one of 3.
[Appendix 5]
The information processing according to appendix 4, wherein the estimation unit (104, 304) estimates the number of the lost frames in units of radio frames having the same sequence number among the radio frames detected by the monitor device (30). Device (100, 40).
[Appendix 6]
The estimation unit (104, 304)
By inputting into the first transition model the transmission rate of the radio frame transmitted immediately before the retransmission frame for which there is no corresponding initial transmission frame among the radio frames detected by the monitor device (30), the immediately preceding Obtain the probability of transition from the transmission rate of the radio frame transmitted to each initial transmission rate to
By inputting each initial transmission rate and the transmission rate of the retransmission frame without the corresponding initial transmission frame into the second transition model, the transmission rate of the retransmission frame without the corresponding initial transmission frame is input from each initial transmission rate. Calculate the expected value for the number of retransmitted frames to reach the transmission rate,
The information processing apparatus (100, 40) according to appendix 5, wherein the number of lost frames is estimated based on the obtained probability of transition to each initial transmission rate and the calculated expected value.
[Appendix 7]
7. The information according to any one of appendices 1 to 6, further comprising an evaluation index generation unit (305) that generates an index for evaluating the state of the wireless communication system based on the estimated number of lost frames. a processor (100, 40);
[Appendix 8]
The evaluation index generation unit (305) according to appendix 7, wherein the estimated number of lost frames is used to calculate a retransmission rate indicating a ratio of retransmission frames to radio frames transmitted by the terminal (10). Information processing device (100, 40).
[Appendix 9]
The information processing device (100, 40) according to appendix 7, wherein the evaluation index generation unit (305) calculates a band occupation time per unit time using first and second transition models.
[Appendix 10]
The first transition model generation unit (102, 302) generates the first transition model for each terminal (10) and each radio wave intensity,
The information processing according to any one of appendices 1 to 9, wherein the second transition model generation unit (103, 303) generates the second transition model for each terminal (10) and for each radio wave intensity. Device (100, 40).
[Appendix 11]
The first transition model generation unit (102, 302) generates the first transition model using a radio frame having radio field intensity equal to or greater than a predetermined intensity,
11. The information processing device according to appendix 10, wherein the second transition model generation unit (103, 303) generates the second transition model using a radio frame having a radio wave intensity equal to or greater than a predetermined intensity. 40).
[Appendix 12]
12. The information processing apparatus (100, 40) according to any one of appendices 1 to 11, wherein each of said first and second transition models is a Markov model.
[Appendix 13]
a monitor device (30) for detecting a radio frame transmitted by the terminal (10);
an information processing device (100, 40) connected to the monitor device (30);
including
The information processing device (100, 40)
an acquisition unit (101, 301) for acquiring a radio frame transmitted by a terminal (10) and detected by the monitor device (30);
a first transition model generation unit (102, 302) for generating a first transition model regarding a transmission rate of the first transmission frame among the detected radio frames for each terminal (10);
a second transition model generation unit (103, 303) for generating a second transition model regarding a transmission rate of a retransmission frame among the detected radio frames for each terminal (10);
An estimating unit (104, 304) for estimating the number of lost frames transmitted by the terminal (10) but not detected by the monitoring device (30) using the first and second transition models. )and,
A wireless communication system comprising:
[Appendix 14]
obtaining a radio frame transmitted by the terminal (10) and detected by the monitor device (30);
generating for each terminal (10) a first transition model regarding the transmission rate of the first transmission frame among the detected radio frames;
generating for each terminal (10) a second transition model regarding a transmission rate of retransmission frames among the detected radio frames;
An information processing method, comprising estimating the number of lost frames transmitted by a terminal (10) that cannot be detected by the monitor device (30) using the first and second transition models. .
[Appendix 15]
a process of acquiring a radio frame transmitted by the terminal (10) and detected by the monitor device (30);
a process of generating, for each terminal (10), a first transition model regarding the transmission rate of the first transmission frame among the detected radio frames;
a process of generating, for each terminal (10), a second transition model regarding a transmission rate of retransmission frames among the detected radio frames;
a process of estimating the number of lost frames transmitted by the terminal (10) but not detected by the monitor device (30) using the first and second transition models;
A program that causes the computer (311) to execute
Note that the modes of supplementary notes 13 to 15 can be developed into the modes of supplementary notes 2 to 12 in the same way as the form of supplementary note 1.

It should be noted that the respective disclosures of the cited prior art documents are incorporated herein by reference. Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Those skilled in the art will appreciate that these embodiments are illustrative only and that various modifications can be made without departing from the scope and spirit of the invention.

10, 10-1 to 10-3 Terminal 20 Access point 30 Monitor device 40 Evaluation device 100 Information processing device 101 Acquisition unit 102, 302 First transition model generation unit 103 303 Second transition model generation unit 104 Estimation unit 201, 301 communication control unit 202 radio frame acquisition unit 211 antenna 304 loss frame number estimation unit 305 evaluation index generation unit 306 storage unit 311 processor 312 memory 313 input/output interface 314 communication interface

Claims (15)

an acquisition unit that acquires a radio frame transmitted by a terminal and detected by a monitor device;
a first transition model generation unit that generates a first transition model regarding a transmission rate of an initial transmission frame among the detected radio frames for each terminal;
a second transition model generation unit that generates a second transition model regarding a transmission rate of a retransmission frame among the detected radio frames for each terminal;
an estimating unit that uses the first and second transition models to estimate the number of lost frames transmitted by the terminal that cannot be detected by the monitoring device;
An information processing device. The information according to claim 1, wherein the first transition model is a probability model that models the probability of each transmission rate that can be set for transmission of the initial transmission frame when the terminal transmits the initial transmission frame. processing equipment. 3. The information processing apparatus according to claim 2, wherein the second transition model is a probability model that models the probability of each transmission rate that can be set for transmission of the retransmission frame when the terminal transmits the retransmission frame. . 4. The estimator according to any one of claims 1 to 3, wherein said estimation unit estimates the number of lost frames with respect to a radio frame having a sequence number in which an initial transmission frame does not exist among radio frames detected by said monitor device. The information processing device described. 5. The information processing apparatus according to claim 4, wherein said estimation unit estimates the number of said lost frames in units of radio frames having the same sequence number among radio frames detected by said monitor device. The estimation unit
By inputting the transmission rate of the radio frame transmitted immediately before the retransmission frame for which there is no corresponding initial transmission frame among the radio frames detected by the monitoring device into the first transition model, Obtain the probability of transition from the transmission rate of the radio frame obtained to each initial transmission rate,
By inputting each initial transmission rate and the transmission rate of the retransmission frame without the corresponding initial transmission frame into the second transition model, the transmission rate of the retransmission frame without the corresponding initial transmission frame is input from each initial transmission rate. Calculate the expected value for the number of retransmitted frames to reach the transmission rate,
6. The information processing apparatus according to claim 5, wherein the number of lost frames is estimated based on the obtained probability of transition to each initial transmission rate and the calculated expected value. The information processing apparatus according to any one of claims 1 to 6, further comprising an evaluation index generator that generates an index for evaluating the state of the wireless communication system based on the estimated number of lost frames. . 8. The information processing apparatus according to claim 7, wherein said evaluation index generator calculates a retransmission rate indicating a ratio of retransmission frames to radio frames transmitted by said terminal, using said estimated number of lost frames. 8. The information processing apparatus according to claim 7, wherein said evaluation index generation unit calculates band occupancy time per unit time using first and second transition models. The first transition model generation unit generates the first transition model for each terminal and each radio wave intensity,
The information processing apparatus according to any one of claims 1 to 9, wherein said second transition model generation unit generates said second transition model for each terminal and for each radio wave intensity. The first transition model generation unit generates the first transition model using a radio frame having a radio wave intensity equal to or greater than a predetermined intensity,
11. The information processing apparatus according to claim 10, wherein said second transition model generation unit generates said second transition model using a radio frame having radio field intensity equal to or greater than a predetermined intensity. 12. The information processing apparatus according to claim 1, wherein each of said first and second transition models is a Markov model. a monitor device that detects a radio frame transmitted by a terminal;
an information processing device connected to the monitor device;
including
The information processing device is
an acquisition unit that acquires a radio frame transmitted by a terminal and detected by the monitor device;
a first transition model generation unit that generates a first transition model regarding a transmission rate of an initial transmission frame among the detected radio frames for each terminal;
a second transition model generation unit that generates a second transition model regarding a transmission rate of a retransmission frame among the detected radio frames for each terminal;
an estimating unit that uses the first and second transition models to estimate the number of lost frames transmitted by the terminal that cannot be detected by the monitoring device;
A wireless communication system comprising: Acquiring a radio frame transmitted by a terminal and detected by a monitoring device,
generating for each terminal a first transition model regarding the transmission rate of the first transmission frame among the detected radio frames;
generating, for each terminal, a second transition model regarding a transmission rate of retransmission frames among the detected radio frames;
An information processing method, comprising estimating the number of lost frames, which are wireless frames transmitted by a terminal and which cannot be detected by the monitor device, using the first and second transition models. A process of acquiring a wireless frame transmitted by a terminal and detected by a monitor device;
a process of generating, for each terminal, a first transition model regarding the transmission rate of the first transmission frame among the detected radio frames;
a process of generating, for each terminal, a second transition model regarding a transmission rate of retransmission frames among the detected radio frames;
a process of estimating the number of lost frames transmitted by a terminal and not detected by the monitor device using the first and second transition models;
A program that makes a computer run

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