JP7740503B2 - Received power prediction method and received power prediction system - Google Patents

Description

The present invention relates to a received power prediction method and a received power prediction system.

Technologies for predicting wireless communication quality in wireless communication systems are known. For example, one known technology assumes a static environment with buildings, trees, and other obstacles whose position and size do not change on a second-by-second basis, and predicts the received power of a communication terminal based on past measurements of the received power at that position.

Keisuke Wakao, Kenichi Kawamura, Takatsugu Moriyama, "Quality Prediction Technology for Optimal Use of Multiple Wireless Access Systems," NTT Technical Journal, April 2020, pp. 11-13 "How do we determine the location of people and objects indoors? A summary of indoor positioning methods," [online], Techfirm Blog, [Retrieved October 7, 1991], Internet <URL: https://www.techfirm.co.jp/blog/indoor-localization>

However, with conventional technology, it is difficult to predict the received power of a communication terminal in a dynamic environment where moving objects such as people, vehicles, and robots are present, taking into account the blocking of radio waves by moving objects.

An embodiment of the present invention has been made in consideration of the above-mentioned problems, and provides a received power prediction method that can predict the received power of a communication terminal in a dynamic environment where mobile objects are present, taking into account the blocking of radio waves by mobile objects.

In order to solve the above problem, a received power prediction method according to an embodiment of the present invention includes a received power prediction system that performs an acquisition process to acquire dynamic environmental information of an object, including information indicating the position of a moving body in a specified area; a process to acquire the position of a communication terminal in the specified area; a process to predict the predicted position of the communication terminal after a specified time has elapsed; a process to predict the dynamic environmental information after the specified time has elapsed; and a prediction process to predict the received power of the communication terminal after the specified time has elapsed by deleting, from all paths included in path information of radio wave propagation calculated in advance at the predicted position of the communication terminal or an evaluation point around the predicted position, paths that are blocked by the position of the moving body included in the dynamic environmental information after the specified time has elapsed.

According to an embodiment of the present invention, a received power prediction method can be provided that can predict the received power of a communication terminal in a dynamic environment where mobile objects are present, taking into account the blocking of radio waves by mobile objects.

1 is a diagram illustrating an example of a system configuration of a received power prediction system according to an embodiment of the present invention. 10A and 10B are diagrams for explaining a prediction process of received power according to the present embodiment. FIG. 10 is a diagram for explaining a pre-processing according to the present embodiment. FIG. 10 is a diagram illustrating another example of the system configuration of the received power prediction system according to the present embodiment. 10 is a flowchart illustrating an example of a process for predicting received power according to the first embodiment; 10 is a flowchart illustrating an example of a process for predicting received power according to a second embodiment; FIG. 10 is a diagram (1) for explaining a prediction process of received power according to the second embodiment. FIG. 10 is a diagram (2) for explaining the process of predicting received power according to the second embodiment. 10 is a flowchart illustrating an example of pre-processing according to the present embodiment. FIG. 2 is a diagram illustrating an example of a hardware configuration of a prediction device according to the present embodiment. FIG. 2 is a diagram illustrating an example of a hardware configuration of a communication terminal according to the present embodiment. FIG. 1 is a diagram (1) for explaining a problem of the present embodiment. FIG. 10 is a diagram (2) for explaining the problem of the present embodiment.

The following describes an embodiment of the present invention (the present embodiment) with reference to the drawings. The embodiment described below is merely an example, and the embodiments to which the present invention can be applied are not limited to the following embodiment.

<System Configuration>
The received power prediction system 1 according to this embodiment is a system that predicts the received power that a communication terminal receives from a wireless base station in a wireless communication network.

Conventional quality prediction systems such as those shown in Non-Patent Document 1 predict wireless communication quality from actual measurement values of communication quality at evaluation points acquired in advance, the current position of the communication terminal, and movement information of the communication terminal. For example, as shown in Figure 12, this conventional technology makes it possible to predict the received power received by communication terminal 902 from wireless base station 901 based on actual measurement values of received power acquired in advance in a static environment 1200 containing only stationary objects such as buildings 1203.

However, with this method, for example, in a dynamic environment 1300 where there are moving objects such as a vehicle 1301, a person 1302, and a robot 1303, as shown in Figure 13, radio waves are blocked by the moving objects, making it difficult to predict the received power received by the communication terminal 1202 from the wireless base station 1201.

Therefore, the received power prediction system 1 of this embodiment has a system configuration, for example, as shown in Figure 1 or Figure 4, so that it can predict the received power received by the communication terminal 1202 in a dynamic environment 1300 in which mobile objects exist, taking into account the blocking of radio waves by mobile objects.

(System Configuration 1)
1 is a diagram showing an example of the system configuration of a received power prediction system according to this embodiment. In the example of FIG. 1, the received power prediction system 1 is realized by a prediction device 100.

The prediction device 100 is an information processing device having a computer configuration, or a system including multiple computers. The prediction device 100 realizes functional components such as an environmental information acquisition unit 101, a terminal position acquisition unit 102, a terminal position prediction unit 103, an environmental information prediction unit 104, a received power prediction unit 105, and a communication unit 106 by executing a predetermined program on the computer provided in the prediction device 100. Note that at least a portion of the above functional components may be realized by hardware.

In addition, the prediction device 100 realizes an environmental information storage unit 111, a terminal position storage unit 112, an estimation result storage unit 113, etc. using a storage device and memory, etc., provided in the prediction device 100.

The environmental information acquisition unit 101 executes an acquisition process to acquire dynamic environmental information of objects in a predetermined area. For example, as shown in FIG. 2, the environmental information acquisition unit 101 acquires dynamic environmental information within a building 201, which is an example of a predetermined area, using a three-dimensional sensor such as a LiDAR 211, a stereo camera 212, a depth camera 213, a camera 214, or a wireless sensing device 215. This dynamic environmental information includes, for example, information indicating the positions of moving bodies 202a, 202b, and 202c within the building 201.

The LiDAR (Light Detection and Ranging, or Laser Imaging Detection and Ranging) 211 is a device that measures the distance to an object by irradiating the object with light such as laser light and detecting the reflected light using an optical sensor or the like. The environmental information acquisition unit 101 may use the LiDAR 211 to sense a predetermined area, such as inside a building 201, to acquire three-dimensional point cloud data, and use the acquired three-dimensional point cloud data as dynamic environmental information.

The stereo camera 212 is a camera that can measure the distance to an object along with an image of the object by simultaneously capturing images of the object from two different directions. The environmental information acquisition unit 101 may use the stereo camera 212 to sense a predetermined area, such as the inside of a building 201, to acquire three-dimensional point cloud data, and use the acquired three-dimensional point cloud data as dynamic environmental information.

The depth camera 213 is a camera that captures a depth image including depth data indicating the distance to the object by photographing the object. The environmental information acquisition unit 101 may use the depth camera 213 to capture an image of a predetermined area, such as the inside of a building 201, to acquire depth data, and use the acquired depth data as dynamic environmental information.

Camera 214 is, for example, a monocular camera that captures normal camera images that do not include depth data. Deep learning has been used to realize technology for estimating depth images from monocular camera images that do not include depth data. Environmental information acquisition unit 101 may generate depth data from the camera images captured by camera 214 using deep learning, and use the generated depth data as dynamic environmental information.

The wireless sensing device 215 is a device that measures the position of an object using wireless communication or radio wave reflection. For example, a technology has been developed that uses multiple subcarriers, such as wireless LAN (Local Area Network) communication, to acquire CSI (Channel State Information) for each subcarrier, and inputs the acquired CSI into a trained machine learning model to acquire the position of an object. The wireless sensing device 215 may also be a millimeter-wave radar capable of measuring the distance, angle, or speed of an object. The environmental information acquisition unit 101 may use the wireless sensing device 215 to sense a specified area, such as within a building 201, to acquire position data of objects in the specified area, and use the acquired position data as dynamic environmental information.

Furthermore, the environmental information acquisition unit 101 may acquire dynamic environmental information of objects in a specified area using other positioning methods. In this way, the dynamic environmental information acquired by the environmental information acquisition unit 101 may include three-dimensional point cloud data, depth data, or position data of objects acquired by a three-dimensional sensor, and may be data that can identify the position of a moving object in a specified area. Furthermore, the positioning method for acquiring dynamic environmental information may be any positioning method.

The terminal position acquisition unit 102 executes a process for acquiring the position of a communication terminal in a specified area. For example, the communication terminal adds position information (coordinate information) indicating the position of the terminal and transmits request information to the prediction device 100 requesting acquisition of a predicted value of received power. The terminal position acquisition unit 102 may acquire the position of the communication terminal from request information received from the communication terminal by the communication unit 106, for example. However, this is not limited to this, and the terminal position acquisition unit 102 may acquire the position of the communication terminal using various three-dimensional sensors, similar to the environmental information acquisition unit 101.

The terminal position prediction unit 103 executes a process to predict the predicted position of the communication terminal after a predetermined time (t seconds) has elapsed from the present time. For example, the terminal position acquisition unit 102 stores the acquired position of the communication terminal in the terminal position storage unit 112. The terminal position prediction unit 103 may also predict the position of the communication terminal after a predetermined time has elapsed, for example, by linear prediction, based on the position history of the communication terminal stored in the terminal position storage unit 112.

As another example, the terminal position prediction unit 103 may be included in the communication terminal. In this case, the terminal position prediction unit 103 of the communication terminal calculates the predicted position of the communication terminal after a predetermined time (t seconds) has elapsed based on the current position of the communication terminal and the movement of the communication terminal (movement direction, movement speed, etc.) measured by sensors such as an acceleration sensor and an angle sensor. The communication terminal also sends request information to the prediction device 100 requesting acquisition of a predicted value of received power, along with the position of the communication terminal and the predicted position of the communication terminal after the predetermined time has elapsed.

The environmental information prediction unit 104 executes a process of predicting dynamic environmental information after a predetermined time (t seconds) has elapsed from the present time. For example, the environmental information acquisition unit 101 stores the acquired dynamic environmental information in the environmental information storage unit 111. Furthermore, the environmental information prediction unit 104 predicts dynamic environmental information after a predetermined time has elapsed, for example, by linear prediction, based on the history of dynamic environmental information stored in the environmental information storage unit 111.

For example, the environmental information prediction unit 104 acquires the positions of the mobile objects 202a, 202b, and 202c shown in FIG. 2 from dynamic environmental information, and stores the acquired position history of the mobile objects 202a, 202b, and 202c in the environmental information storage unit 111, etc. The environmental information prediction unit 104 may also calculate the movement of the mobile object (movement direction, movement speed, etc.) from the position history of the mobile object stored in the environmental information storage unit 111, etc., and predict the position of the mobile object after a predetermined time has elapsed from the current position of the mobile object and the movement of the mobile object. Alternatively, the environmental information prediction unit 104 may predict the position of the mobile object after a predetermined time has elapsed by inputting the movement history of the mobile object into a prediction model that has been machine-learned in advance to predict the position of the mobile object after a predetermined time has elapsed from the movement history of the mobile object.

The received power prediction unit 105 predicts the received power of the communication terminal after a predetermined time has elapsed based on radio wave propagation path information 206 generated in advance by ray tracing, etc., at the predicted location of the communication terminal or an evaluation point surrounding the predicted location, and the position of the mobile body after a predetermined time has elapsed.

2, path information 206 is information on multiple radio wave propagation paths through which radio waves transmitted by radio base station (BS) 204 are received at evaluation point 205, and preferably includes information on the received power received on each path. The received power prediction unit 105 predicts the received power of communication terminal 203 after a predetermined time has elapsed by deleting paths in the direction of mobile bodies 202a and 202b after a predetermined time has elapsed from radio wave propagation path information 206 generated in advance at evaluation points around the predicted position of communication terminal 203.

In addition, the prediction device 100 pre-stores in the estimation result memory unit 113 path information 206 of radio wave propagation at multiple evaluation points, which has been obtained in advance, for example, by pre-processing such as that shown in Figure 3.

Figure 3 is a diagram for explaining the pre-processing according to this embodiment. This pre-processing is performed, for example, by an information processing device having a computer configuration, using a program for radio wave propagation simulation such as ray tracing. Note that the information processing device used for the pre-processing may be the same information processing device as the prediction device 100, or may be an information processing device different from the prediction device 100.

The information processing device acquires static environmental information from a building DB (Database) (or map DB) 311, CAD (Computer Aided Design) data 312, or BIM (Building Information Modeling) data 313, etc., which represent the structure of the building 201 (step S11).

The information processing device also sets multiple evaluation points 205 within a building 201, which is an example of a specified area, and generates (calculates) path information 206 of radio wave propagation at each of the set evaluation points 205 using ray tracing or the like (step S12).

This allows, for example, radio wave propagation path information 206 to be obtained that has been generated in advance at multiple evaluation points 205 within the building 201. The prediction device 100 stores the radio wave propagation path information 206 obtained by this pre-processing in the estimation result storage unit 113 in advance.

Now, returning to Figure 1, we will continue to explain the functional configuration of the prediction device 100. The communication unit 106 performs communication processing to communicate with the communication terminal 203, etc. via the communication network.

The environmental information storage unit 111 stores dynamic environmental information, etc., acquired by the environmental information acquisition unit 101. The terminal position storage unit 112 stores the position of the communication terminal 203 acquired by the terminal position acquisition unit 102. The estimation result storage unit 113 pre-stores radio wave propagation path information 206 that was generated in advance at multiple evaluation points and acquired in pre-processing.

With the above functional configurations, the environmental information acquisition unit 101 of the prediction device 100 acquires dynamic environmental information using various three-dimensional sensors, for example, as shown in Figure 2 (step S1). This dynamic environmental information includes, for example, information indicating the positions of mobile objects 202a, 202b, and 202c within a specified area. In addition, the terminal position acquisition unit 102 of the prediction device 100 acquires the position of the communication terminal 203 (step S2).

Next, the terminal position prediction unit 103 of the prediction device 100 predicts the predicted position of the communication terminal 203 after a predetermined time (t seconds) has passed, and the environmental information prediction unit 104 predicts dynamic environmental information after the predetermined time has passed (step S3).

The reception power prediction unit 105 of the prediction device 100 also acquires, from the estimation result storage unit 113, radio wave propagation path information 206 that has been generated in advance for the predicted position of the communication terminal 203 after a predetermined time has elapsed or for an evaluation point in the vicinity of the predicted position. Furthermore, the reception power prediction unit 105 eliminates the path in the direction in which the mobile bodies 202a and 202b are located from the acquired radio wave propagation path information 206 after a predetermined time has elapsed, and predicts the reception power of the communication terminal 203 after a predetermined time has elapsed.

Through the above processing, the reception power prediction system 1 can predict the reception power of the communication terminal 203 in a dynamic environment where mobile objects are present, taking into account the blocking of radio waves by mobile objects.

Note that the system configuration of the received power prediction system 1 shown in Figure 1 is an example. At least some of the functional components of the prediction device 100 may be included in the communication terminal 203.

(System Configuration 2)
Fig. 4 shows another example of the system configuration of the received power prediction system according to the present embodiment. In the example of Fig. 4, the received power prediction system 1 includes a prediction device 100 and a communication terminal 203 that can communicate with the prediction device 100 via a communication network 2.

In the received power prediction system 1 shown in Figure 4, the terminal position acquisition unit 102 and terminal position prediction unit 103 described in Figure 1 are included in the communication terminal 203, rather than the prediction device 100.

The communication terminal 203 is a wireless communication device having the configuration of a computer. The communication terminal 203 realizes functional components such as the terminal position acquisition unit 102, the terminal position prediction unit 103, and the communication unit 401 by executing a predetermined program on the computer provided in the communication terminal 203. Note that at least a portion of the above functional components may be realized by hardware.

The terminal position acquisition unit 102 acquires the current position of the communication terminal 203 on the communication terminal 203 side, for example, by positioning using a GPS (Global Positioning System) device and autonomous navigation using sensors such as an acceleration sensor and an angle sensor.

The terminal position prediction unit 103 executes a process on the communication terminal 203 side to predict the predicted position of the communication terminal after a predetermined time (t seconds) has elapsed from the current time. For example, the terminal position prediction unit 103 may predict the position of the communication terminal 203 after a predetermined time has elapsed, for example, by linear prediction, based on the position history of the communication terminal 203 acquired by the terminal position acquisition unit 102.

Alternatively, the terminal position prediction unit 103 may calculate the predicted position of the communication terminal 203 after a predetermined time (t seconds) has elapsed from the current position of the communication terminal 203 and the movement of the communication terminal (direction of movement, speed of movement, etc.) measured by sensors such as an acceleration sensor or angle sensor.

The communication unit 401 connects to the communication network 2 using a predetermined wireless communication such as 5G (5th Generation) or LTE (Long Term Evolution), and executes communication processing to communicate with the prediction device 100, etc. For example, the communication unit 401 adds information about the communication terminal, the position of the communication terminal 203, the predicted position of the communication terminal 203, etc. to request information requesting the prediction device 100 to predict the received power, and transmits the request information to the prediction device 100. The communication unit 401 also receives the prediction result of the received power transmitted by the prediction device 100.

In the system configuration of Figure 4, the request information received by the communication unit 106 from the communication terminal 203 in the prediction device 100 includes the position of the communication terminal 203 and the predicted position of the communication terminal 203 after a predetermined time has elapsed. Therefore, the prediction device 100 does not need to have a terminal position acquisition unit 102, a terminal position prediction unit 103, etc.

In this way, each functional configuration provided by the prediction device 100 described in Figure 1 may be provided by the received power prediction system 1, and may be provided by any device within the system.

<Processing flow>
Next, the processing flow of the received power prediction method according to this embodiment will be described.

<Prediction of received power>
[Example 1]
Fig. 5 is a flowchart showing an example of a received power prediction process according to the first embodiment. This process shows an example of a received power prediction process in which the received power prediction system 1 having the functional configuration shown in Fig. 1 or 4 predicts the received power of the communication terminal 203 after a predetermined time has elapsed. It is assumed that, at the start of the process shown in Fig. 5, the estimation result storage unit 113 stores path information 206 of radio wave propagation measured in advance at a plurality of evaluation points within a predetermined area.

In step S501, the environmental information acquisition unit 101 acquires dynamic environmental information of objects in a specified area. For example, the environmental information acquisition unit 101 acquires dynamic environmental information using a LiDAR 211, a stereo camera 212, a depth camera 213, a camera 214, or a wireless sensing device 215 installed in the specified area. This dynamic environmental information includes information indicating the positions of moving objects in the specified area.

In step S502, the terminal location acquisition unit 102 acquires the location of the communication terminal 203 in a specified area. Note that this process may be performed by the prediction device 100 or the communication terminal 203.

In step S503, the terminal position prediction unit 103 predicts the predicted position of the communication terminal 203 after t seconds (after a predetermined time has elapsed). Note that this process may be performed by the prediction device 100 or the communication terminal 203.

In step S504, the environmental information prediction unit 104 predicts dynamic environmental information after t seconds (after a predetermined time has elapsed). The predicted dynamic environmental information includes information indicating the predicted position of a moving object in a predetermined area after t seconds.

In step S505, the reception power prediction unit 105 predicts the path (radio wave propagation path) that will be blocked by the predicted position of the mobile body t seconds later at the predicted position of the communication terminal 203 t seconds later.

For example, the reception power prediction unit 105 acquires path information 206 of radio wave propagation measured in advance at the predicted position of the communication terminal 203 after t seconds or at an evaluation point in the vicinity of the predicted position. Furthermore, the reception power prediction unit 105 predicts, from the acquired path information 206 of radio wave propagation, paths that will be blocked by the predicted position of the mobile body after t seconds.

In step S506, the received power prediction unit 105 subtracts the received power due to the blocked paths from all paths included in the acquired radio wave propagation path information 206 and predicts (calculates) the communication terminal 203 t seconds later.

For example, as shown in step S4 of Figure 2, the received power prediction unit 105 removes paths that will be blocked by mobile bodies 202a and 202b after t seconds from the acquired radio wave propagation path information 206, and calculates the received power of the communication terminal 203 after t seconds.

By processing Figure 5, the received power prediction system 1 can predict the received power of the communication terminal 203 in a dynamic environment where mobile objects are present, taking into account the blocking of radio waves by mobile objects.

[Example 2]
Fig. 6 is a flowchart showing an example of a received power prediction process according to the second embodiment. This process shows another example of a received power prediction process in which the received power prediction system 1 having the functional configuration shown in Fig. 1 or 4 predicts the received power of the communication terminal 203 after a predetermined time has elapsed. Among the processes shown in Fig. 6, the processes of steps S501 to S505 are the same as the received power prediction process according to the first embodiment described in Fig. 5, and therefore, description thereof will be omitted here.

In step S601, the received power prediction unit 105 predicts the received power of the communication terminal t seconds later based on the proportion to which the first Fresnel zone of each path in the acquired radio wave propagation path information 206 will be blocked by the predicted position of the mobile body t seconds later.

Figures 7 and 8 are diagrams for explaining the received power prediction process according to Example 2. A method for calculating the electric field at the reception point from the blocking ratio of an obstructing object within the radius of the first Fresnel zone is known (see, for example, Patent Document: JP 2020-31366 A).

As shown in Figure 7, the propagation path of radio waves transmitted from the radio base station (BS) 204 until they reach the communication terminal (UE) 203 is a three-dimensional space (spheroid) centered on the shortest path 702 connecting the radio base station 204 and the communication terminal 203 with a line segment. This three-dimensional radio wave propagation path is called a Fresnel zone. Furthermore, the innermost area of the Fresnel zone where most of the radio wave energy is present is called the first Fresnel zone 701.

According to the above-mentioned patent document, if the reception electric field of the communication terminal 203 when the mobile object 202a is not present is E0(i), the reception electric field E1(i) of the communication terminal 203 when the mobile object 202a is present is:
It can be calculated using the following (Equation 1) and (Equation 2).

(In the case of direct waves)
As shown in FIG. 7, when the propagation path of the radio wave from the wireless base station 204 to the communication terminal 203 is a direct wave, the received electric field E1(i) is calculated by the following (Equation 1).
|E1(i)| ² = |E0(i)| ² × r(i) ... (Equation 1)
Here, r(i) is the blocking ratio of the moving body 202a to the first Fresnel zone 701. For example, if the area indicated by the moving body 202a is 70% of the area of the first Fresnel zone 701 at the position of the moving body 202a, the blocking ratio is 70% (0.7).

(In the case of reflected waves)
As shown in FIG. 8, when the propagation path from the radio base station (BS) 204 to the communication terminal (UE) 203 is a reflected wave, the received electric field E1(i) is calculated by the following (Equation 2).
|E1(i)| ² = |E0(i)| ² × r(i)/La … (Formula 2)
Here, La is the reflection loss, and an approximate value determined by the material of the reflecting surface 801, etc., is used.

Furthermore, if there are N paths from wireless base station 204 to communication terminal 203, the received electric field E1(i) calculated for each path is summed to calculate the transmitted and received electric field E1 _total received by communication terminal 203 (Equation 3).

Preferably, the transmission/reception electric field E1 _total is calculated by adding diffracted waves in addition to direct waves and reflected waves.

According to the second embodiment, the received power prediction system 1 can calculate the blocking rate by a moving object for the first Fresnel zone of each path in the radio wave propagation path information 206, thereby more quickly calculating the received power (or attenuation) of the communication terminal 203.

<Pre-processing>
9 is a flowchart showing an example of pre-processing according to this embodiment, in which an information processing device having a computer configuration acquires path information of radio wave propagation at multiple evaluation points within a predetermined area.

In step S901, the information processing device acquires static environmental information for a specified area from the building DB (or map DB) 311, CAD data 312, BIM data 313, etc. This static environmental information includes, for example, information indicating the positions of objects that do not generally move, such as buildings, walls, and floors.

In step S902, the information processing device sets the location of the wireless base station in the static environmental information of a specified area.

In step S903, the information processing device sets multiple evaluation points in a planar manner in the static environmental information of a specified area.

In step S904, the information processing device generates (calculates) path information between the wireless base station and each evaluation point by radio wave propagation estimation such as ray tracing.

By processing the information processing device in Figure 9, the information processing device can generate radio wave propagation path information 206 generated at multiple evaluation points to store in the estimation result memory unit 113.

<Hardware configuration example>
(Hardware configuration of prediction device)
Fig. 10 is a diagram showing an example of the hardware configuration of a prediction device according to this embodiment. The prediction device 100 has, for example, the configuration of a computer 1000 as shown in Fig. 10. In the example of Fig. 10, the computer 1000 has a processor 1001, a memory 1002, a storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus B, etc.

The processor 1001 is, for example, an arithmetic device such as a CPU (Central Processing Unit) that realizes various functions by executing predetermined programs. The memory 1002 is a storage medium readable by the computer 1000 and includes, for example, RAM (Random Access Memory) and ROM (Read Only Memory). The storage device 1003 is a computer-readable storage medium and may include, for example, an HDD (Hard Disk Drive), an SSD (Solid State Drive), various optical disks, and magneto-optical disks.

The communication device 1004 includes one or more pieces of hardware (communication devices) for communicating with other devices via a wireless or wired network. The input device 1005 is an input device (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.) that accepts input from the outside. The output device 1006 is an output device (e.g., a display, speaker, LED lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one configuration (e.g., an input/output device such as a touch panel display).

Bus B is commonly connected to each of the above components and transmits, for example, address signals, data signals, and various control signals. Note that processor 1001 is not limited to a CPU, but may also be, for example, a DSP (Digital Signal Processor), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

(Hardware configuration of communication terminal)
11 is a diagram showing an example of the hardware configuration of a communication terminal according to this embodiment. The communication terminal 203 includes, for example, a GPS device 1101, a sensor 1102, and the like in addition to the hardware configuration of the computer 1000 described in FIG.

The GPS device 1101 is a positioning device that receives positioning signals transmitted by GPS satellites and outputs location information indicating the current position of the communication terminal 203. The sensor 1102 is a detection device that detects the movement of the communication terminal 203, such as an acceleration sensor or angle sensor.

(supplement)
The prediction device 100 in this embodiment is not limited to being realized by a dedicated device, but may also be realized by a general-purpose computer. In this case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed to realize the function. Note that the term "computer system" here includes hardware such as an OS and peripheral devices.

In addition, "computer-readable recording media" includes various storage devices such as portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as hard disks built into computer systems. Furthermore, "computer-readable recording media" may also include devices that dynamically store programs for a short period of time, such as communication lines when transmitting a program via a network such as the Internet or a communication line such as a telephone line, or devices that store programs for a certain period of time, such as volatile memory within a computer system that serves as a server or client in such cases.

Furthermore, the above program may be designed to realize some of the functions described above, or may be capable of realizing the functions described above in combination with a program already recorded in a computer system, or may be realized using hardware such as a PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array).

<Effects of the embodiment>
According to this embodiment, it is possible to provide a received power prediction method that can predict the received power of a communication terminal in a dynamic environment where moving objects exist, taking into account the blocking of radio waves by moving objects.

In addition, the above effects will enable stable use of wireless communications or applications in wireless communication systems, such as switching the location (wireless base station) where a communication terminal is accommodated due to deterioration in communication quality, controlling communication parameters, or changing the driving route of an autonomous vehicle.

<Summary of the embodiment>
This specification discloses at least the following wireless communication methods and wireless communication systems.
(Section 1)
The received power prediction system
an acquisition process for acquiring dynamic environmental information of objects in a predetermined area;
A process of acquiring the location of a communication terminal in the predetermined area;
predicting a predicted location of the communication terminal after a predetermined time has elapsed;
a process of predicting the dynamic environmental information after the predetermined time has elapsed;
a prediction process for predicting the received power of the communication terminal after the predetermined time has elapsed, based on path information of radio wave propagation calculated in advance at the predicted position of the communication terminal or at an evaluation point around the predicted position, and path information of paths blocked by the dynamic environmental information after the predetermined time has elapsed;
A received power prediction method that performs the above.
(Section 2)
2. The reception power prediction method according to claim 1, wherein the dynamic environmental information acquired in the acquisition process includes three-dimensional point cloud data, depth data, or position data of the object acquired by a three-dimensional sensor.
(Section 3)
2. The received power prediction method according to claim 1, wherein the path information of radio wave propagation includes path information at the evaluation point calculated by ray tracing radio wave propagation characteristic estimation using static environmental information of the specified area.
(Section 4)
4. The reception power prediction method according to claim 3, wherein the reception power prediction system has path information of the radio wave propagation calculated in advance at a plurality of evaluation points within the predetermined area.
(Section 5)
the dynamic environmental information after the predetermined time has elapsed includes information indicating a position of a moving object in the predetermined area after the predetermined time has elapsed;
The prediction process is a reception power prediction method described in paragraph 3, in which the prediction process subtracts paths that will be blocked by moving objects in the specified area after the specified time has elapsed from the path information of the radio wave propagation calculated in advance at the evaluation point, and predicts the reception power of the communication terminal after the specified time has elapsed.
(Section 6)
the dynamic environmental information after the predetermined time has elapsed includes information indicating a position of a moving object in the predetermined area after the predetermined time has elapsed;
The prediction process predicts the received power of the communication terminal after the specified time has elapsed based on the blocking rate by a moving object in the specified area for the first Fresnel zone of each path from the path information of the radio wave propagation calculated in advance at the evaluation point.
(Section 7)
an environment information acquisition unit configured to acquire dynamic environment information of objects in a predetermined area;
a terminal location acquisition unit configured to acquire the location of a communication terminal in the predetermined area;
a terminal location predictor configured to predict a predicted location of the communication terminal after a predetermined time has elapsed;
an environmental information prediction unit configured to predict the dynamic environmental information after the predetermined time has elapsed;
a reception power prediction unit configured to predict reception power of the communication terminal after the predetermined time has elapsed, based on path information of radio wave propagation calculated in advance at a predicted position of the communication terminal or an evaluation point around the predicted position, and path information of paths blocked by the dynamic environmental information after the predetermined time has elapsed;
A received power prediction system comprising:

The present embodiment has been described above, but the present invention is not limited to such a specific embodiment, and various modifications and variations are possible within the scope of the gist of the present invention as described in the claims.

1 Received power prediction system 101 Environmental information acquisition unit 102 Terminal position acquisition unit 103 Terminal position prediction unit 104 Environmental information prediction unit 105 Received power prediction unit 113 Estimation result storage unit 113
206 Radio wave propagation path information 211 LiDAR
212 Stereo camera 213 Depth camera 214 Camera 215 Wireless sensing device 205 Evaluation point 701 First Fresnel zone

Claims (6)

The received power prediction system
an acquisition process for acquiring dynamic environmental information of an object, including information indicating the position of a moving object in a predetermined area;
A process of acquiring the location of a communication terminal in the predetermined area;
predicting a predicted location of the communication terminal after a predetermined time has elapsed;
a process of predicting the dynamic environmental information after the predetermined time has elapsed;
a prediction process for predicting the received power of the communication terminal after the predetermined time has elapsed by deleting paths that are blocked by the position of the moving body included in the dynamic environment information from all paths included in path information of radio wave propagation that is calculated in advance at the predicted position of the communication terminal or an evaluation point around the predicted position;
A received power prediction method that performs the above. The received power prediction method of claim 1, wherein the dynamic environmental information acquired in the acquisition process includes three-dimensional point cloud data, depth data, or position data of the object acquired by a three-dimensional sensor. The received power prediction method according to claim 1, wherein the radio wave propagation path information includes path information at the evaluation point generated in advance by estimating radio wave propagation characteristics using static environmental information for the specified area. The received power prediction method described in claim 3, wherein the received power prediction system has path information of the radio wave propagation generated in advance at multiple evaluation points within the specified area. the dynamic environmental information after the predetermined time has elapsed includes information indicating a position of a moving object in the predetermined area after the predetermined time has elapsed;
4. The received power prediction method according to claim 3, wherein the prediction process predicts the received power of the communication terminal after the predetermined time has elapsed by deleting paths that are blocked by a moving object in the predetermined area from all paths included in the path information of radio wave propagation calculated in advance at the evaluation point. an environment information acquisition unit configured to acquire dynamic environment information of an object, including information indicating the position of a moving object in a predetermined area;
a terminal location acquisition unit configured to acquire the location of a communication terminal in the predetermined area;
a terminal location predictor configured to predict a predicted location of the communication terminal after a predetermined time has elapsed;
an environmental information prediction unit configured to predict the dynamic environmental information after the predetermined time has elapsed;
a reception power prediction unit configured to predict reception power of the communication terminal after the predetermined time has elapsed by deleting paths that are blocked by the position of the moving object included in the dynamic environment information from all paths included in path information of radio wave propagation that is calculated in advance at the predicted position of the communication terminal or an evaluation point around the predicted position;
A received power prediction system comprising: