Communication device and program for tracking moving objects

Abstract

Switch the communication device used for tracking moving objects. [Solution] The communication device includes tracking means that tracks a moving object by repeatedly transmitting a sensing signal to a wireless device for reception; acquisition means that causes the wireless device to transmit a first signal directed at the moving object and performs an acquisition process to acquire a first reception result of the first signal at another communication device from another communication device; and instruction means that, when the first reception result acquired from the other communication device satisfies a predetermined criterion, instructs the other communication device to track the moving object.

Description

Technical Field

[0001] The present disclosure relates to a technology for tracking a moving object using wireless signals.

Background Art

[0002] Non-Patent Document 1 discloses various use cases of sensing services in mobile communication networks. In one of the plurality of configurations disclosed by Non-Patent Document 1, a base station apparatus (BS) that is a wireless communication apparatus transmits a signal for sensing (hereinafter referred to as a sensing signal), and a wireless device (WD) feeds back the reception result of the sensing signal to the base station apparatus, whereby the mobile communication network collects sensing data. Based on the collected sensing data, the mobile communication network can detect the environment of the area where the service is provided (hereinafter referred to as a service area), for example, obstacles that hinder the propagation of wireless signals. The obstacles include stationary objects such as buildings and moving objects such as vehicles.

[0003] When an obstacle is moving, the frequency of the sensing signal received by the WD shifts under the influence of the Doppler effect according to its moving speed and moving direction. Therefore, the mobile communication network can determine whether the obstacle is a stationary object or a moving object. By using a signal used for communication as a sensing signal, communication and sensing can be performed efficiently.

[0004] Patent Document 1 discloses a system called ISAC (Integrated Sensing And Communication) or JCAS (Joint Sensing and Communication) that integrates a sensing signal and a communication signal.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] [Non-Patent Document 1] 3GPP(Registered Trademark) TR 22.837, V19.0.0, June 2023 [Overview of the project] [Problems that the invention aims to solve]

[0007] When a mobile communication network wants to track a moving object, such as a vehicle, it is necessary to switch the communication equipment, such as BS, used for tracking the moving object as the object moves.

[0008] This disclosure provides a switching technology for communication devices used for tracking moving objects. [Means for solving the problem]

[0009] According to one aspect of this disclosure, the communication device includes tracking means for tracking a moving object by repeatedly transmitting a sensing signal to a wireless device for reception; acquisition means for causing the wireless device to transmit a first signal directed at the moving object and for performing an acquisition process to acquire a first reception result of the first signal at another communication device from another communication device; and instruction means for instructing the other communication device to track the moving object when the first reception result acquired from the other communication device satisfies a predetermined criterion. [Effects of the Invention]

[0010] According to this disclosure, it is possible to switch the communication device used for tracking a moving object. [Brief explanation of the drawing]

[0011] [Figure 1] A system configuration diagram used to describe the embodiment. [Figure 2] Diagram illustrating the sensing process. [Figure 3] A diagram showing an example of obstacle detection. [Figure 4] Sequence diagram of the sensing process. [Figure 5] A diagram showing examples of sensing results and detection ranges. [Figure 6] A sequence diagram of the process for switching the communication device used for tracking. [Figure 7] A flowchart of the decision-making process. [Figure 8] A diagram showing an example of a communication device configuration. [Modes for carrying out the invention]

[0012] The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more features from the multiple features described in the embodiments may be arbitrarily combined. Furthermore, identical or similar configurations will be given the same reference numeral, and redundant descriptions will be omitted.

[0013] Figure 1 is a system configuration diagram used to describe the embodiment. Figure 1 shows two BS1, one WD2, and a moving obstacle (moving object) 3. The system may also include other BS1, other WD2, and other obstacles (stationary and moving objects), but these are omitted for the sake of simplicity in the diagram. In the following description, the two BS1 will be referred to as BS#1 and BS#2 to distinguish them. According to Figure 1, the moving object 3 is moving from a position closer to BS#1 than to BS#2, towards a position closer to BS#2 than to BS#1.

[0014] As shown in Figure 1, two BSs 1 are configured to be capable of transmitting signals using N transmit beams T#1 to T#N. Further, WD 2 is configured to be capable of receiving signals using M receive beams R#1 to R#M. At least one of N and M is an integer of 2 or more, and the rest is an integer of 1 or more. Alternatively, both N and M are integers of 2 or more. n in the transmit beam T#n (n is an integer from 1 to N) is the number of the transmit beam, and m in the receive beam R#m (m is an integer from 1 to M) is the number of the receive beam. Note that in Figure 1, both BS#1 and BS#2 are configured to be capable of transmitting N transmit beams, but the number of transmit beams that BS#1 and BS#2 can transmit does not need to be the same.

[0015] In the present embodiment, the sensing process includes two processes, a first process and a second process. Figure 2 is an explanatory diagram of the relationship between the first process and the second process. In the following description, the sensing signal used in the first process is referred to as a first sensing signal, and the sensing signal used in the second process is referred to as a second sensing signal. First, the first process will be described.

[0016] As shown in Figure 2, the first process is repeated at a period T1. The BS 1 transmits the first sensing signal on each of the N transmit beams every period T1. For the first sensing signal, for example, a downlink reference signal (RS) defined in 3GPP (registered trademark) can be used. As an example, a channel state information reference signal (CSI-RS) or a positioning reference signal (PRS) can be used as the first sensing signal. The period T1 follows the period of the RS used as the first sensing signal such as CSI-RS or PRS.

[0017] WD2 can obtain a total of N×M reception results by receiving the first sensing signal transmitted by BS1 on each of the N transmit beams with each of the M receive beams. Then, WD2 feeds back the total N×M reception results for each combination of a transmit beam and a receive beam to BS1. The reception results fed back by WD2 to BS1 may include information indicating the combination of the transmit beam and the receive beam that obtained the relevant reception result, as well as the received power, propagation delay, and frequency Doppler shift amount based on the received first sensing signal.

[0018] BS1 and WD2 can detect the presence of an obstacle and its approximate position based on the direction of the transmit beam used for transmitting the first sensing signal, the direction of the receive beam used for receiving the first sensing signal, and the delay from when BS1 transmits the first sensing signal to when WD2 receives the first sensing signal. For example, as shown in Figure 3, when WD2 receives the first sensing signal transmitted on transmit beam T#1 via receive beam R#2, BS1 and WD2 can determine that the first sensing signal received by WD2 on receive beam R#2 is an impulse response corresponding to the reflected wave at obstacle 4, and can detect the presence of obstacle 4 shown in Figure 3 based on its propagation delay.

[0019] The position of the obstacle 4 detected by BS1 or WD2 is the relative position of the obstacle 4 to BS1 or WD2. When the obstacle 4 is moving, the frequency of the first sensing signal received by the receiving beam R#2 shifts due to the Doppler effect according to the speed and direction of movement of the obstacle 4. Therefore, BS1 and WD2 can determine the speed and direction of movement of the obstacle 4 based on the amount of Doppler shift of the first sensing signal. BS1 can perform the first processing individually with each of the multiple WD2s that can receive the first sensing signal from BS1. Based on the reception results of the first sensing signal received from each of the multiple WD2s, BS1 can detect obstacles 4 within the range to which the first sensing signal from BS1 can reach (for example, within the service area of ​​BS1). The first processing detects obstacles 4 that are located within the service area of ​​BS1, and can therefore also be referred to as "detection processing".

[0020] The second process is executed when tracking a moving obstacle 4 detected in the first process, and is also referred to as the tracking process. BS1 may start the second process if it detects a moving object to be tracked in the feedback received from multiple WD2s during the first process. At that time, BS1 selects a WD2 to be used to track the moving object. In the following description, the WD2 selected for tracking the moving object will be referred to as the "tracking WD". In the second process, BS1 transmits a second sensing signal, but notifies the tracking WD of the resources to be used to transmit the second sensing signal each time. The tracking WD feeds back the reception results of the second sensing signal to BS1. The sequence of the second sensing signal, etc., can be determined arbitrarily.

[0021] Figure 4 is a sequence diagram of the sensing process. In the sequence in Figure 4, S1 and S2 are sequences of the first process (detection process) executed every period T1, and S4 to S6 are sequences of the second process, i.e., the tracking process. Although Figure 4 shows only one WD2 selected as the tracking WD in the second process, the first process shown in S1 and S2 can be executed with each of multiple WD2s.

[0022] In S1, BS1 transmits a first sensing signal with each of its N transmit beams. As described above, in this embodiment, the first sensing signal is the downlink RS. WD2 performs sensing based on the first sensing signal transmitted by BS1 in S1. In S2, WD2 transmits N × M reception results (first reception results) of the first sensing signal to BS1. Note that BS1 may also receive first reception results from WD2 (not shown).

[0023] Figure 5(A) shows an example of the first reception result from WD2. In the following, when specific numerical examples are shown, N=M=8. That is, BS1 is configured to transmit beams T#1 to T#8, and WD2 is configured to receive beams R#1 to R#8. #nm (where n and m are integers from 1 to 8) in Figure 5(A) corresponds to the first reception result of the first sensing signal transmitted by transmit beam T#n and received by receive beam R#m. In the following, the combination of the transmit beam number and the receive beam number, i.e., the first reception result indicated by #nm, will be referred to as the first reception result#nm.

[0024] As is clear from the detection principle of obstacle 4 shown in Figure 3, the position of obstacle 4 that can be detected in the first reception result #nm is based on the direction of the transmitting beam T#n and the direction of the receiving beam R#m, that is, the combination of the transmitting beam number n and the receiving beam number m. In other words, the spatial region (detection region) in which obstacle 4 can be detected is determined by the combination of the transmitting beam number n and the receiving beam number m. Thus, the combination of the transmitting beam number and the receiving beam number identifies the detection region of obstacle 4, and below, the region in which obstacle 4 can be detected in the first reception result #nm will also be referred to as the detection region #nm.

[0025] In Figure 5(A), the shaded first reception results #32 and #67 indicate the first reception results in which an obstacle was detected. In other words, in the example in Figure 5(A), obstacle (moving object) 3 is detected in detection area #32, and obstacle 4, which is different from obstacle 3, is detected in detection area #67.

[0026] In S3, BS1 determines, based on the first reception result from each WD2, whether or not there is an obstacle to track, i.e., a moving object to track, based on predetermined criteria. For example, suppose BS1 is set to track vehicles such as cars moving at a speed faster than a predetermined speed. Because the reflection coefficient of radio waves on the surface of a car is high, if the obstacle is a car, the received power of the first sensing signal received by WD2 will be high. Also, the faster the moving speed of the obstacle, the larger the absolute value of the Doppler shift amount of the first sensing signal received by WD2. Therefore, BS1 can determine whether a vehicle is moving at a speed faster than a predetermined speed based on the received power of the first sensing signal at WD2 and the absolute value of the Doppler shift amount. If there is no moving object to track, the tracking process is not started, and therefore S4 to S6 are not executed.

[0027] On the other hand, if BS1 decides in S3 to track the moving object 3 detected in the first reception result #32 in Figure 5(A), BS1 selects a tracking WD in S3. Here, we assume that WD2 shown in Figure 4 is selected as the tracking WD. Also, if BS1 decides to track the moving object 3, it may determine the detection range. Specifically, BS1 estimates multiple detection areas in which the moving object 3 is likely to be located at the time of the next transmission of the second sensing signal, and determines the estimated multiple detection areas as the detection range. For example, BS1 estimates the speed and direction of movement of the moving object 3 based on the Doppler shift amount of the first reception result #32, and estimates one or more detection areas in which the moving object 3 is likely to be located at the time of the next transmission of the second sensing signal based on the estimated speed and direction of movement.

[0028] Figure 5(B) shows an example of the detection range determined by BS1. The shaded area in Figure 5(B) indicates the detection range. According to Figure 5(B), BS1 has defined detection areas #43 to #45, #53 to #55, and #63 to #65 as its detection range. The size of the detection range (number of detection areas) can be dynamically set based on the movement speed of the moving object 3. For example, the detection range can be made larger as the movement speed of the moving object 3 increases.

[0029] Returning to Figure 4, in S4, BS1 notifies WD2, the tracking WD, of the tracking configuration for the moving object 3. The tracking configuration includes an identifier (target ID) assigned to the moving object 3 by BS1, the radio resources used to transmit the second sensing signal in S5, and the detection range determined in S3. The target ID is used to identify the moving object 3 when tracking multiple moving objects 3, and is included in the second reception result transmitted by WD2 in S6. The radio resources are represented by a combination of time resources and frequency resources.

[0030] In S5, BS1 transmits a second sensing signal using the resources notified to WD2 in S4. The second sensing signal can be configured to be transmitted only on the transmission beam included in the detection range. When WD2 acquires the nine second reception results indicated as the detection range, in S6 it notifies BS1 of the nine second reception results. Thereafter, the same process as in S4 to S6 is repeated. Furthermore, as described above, the first process is repeated with a period T1 regardless of whether the second process is being executed or not. In Figure 2, the second process is performed only five times within the period T1 between performing the first process and performing the next first process.

[0031] In this way, by performing the second processing only when tracking a moving object 3 that is moving at a high speed, the execution of unnecessary sensing processing can be suppressed. In other words, the frequency of sensing processing can be appropriately controlled.

[0032] For example, in the configuration shown in Figure 1, let's assume that BS#1 is performing a second process to track the moving object 3 using WD2 as the tracking WD. As shown in Figure 1, if the moving object 3 is moving away from BS#1 and approaching BS#2, it is necessary to switch the BS1 performing the second process from BS#1 to BS#2 (handover) before tracking of the moving object 3 becomes impossible based on the sensing signal from BS#1. The following describes the process for switching the BS1 performing the second process from BS#1 to BS#2.

[0033] Figure 6 is a sequence diagram of the process for determining whether to switch BS1, which performs the second processing, from BS#1 to BS#2. It is assumed that BS1 is configured to receive signals with multiple receiving beams, and WD2 is configured to transmit signals with multiple transmitting beams.

[0034] When BS#1 determines that the tracking moving object 3 is moving towards BS#2, in S10 it configures WD2 to transmit an upward reference signal, such as a sounding reference signal (SRS). Specifically, BS#1 notifies WD2 of the radio resources to which the reference signal should be transmitted and the direction of transmission of the reference signal. The radio resources to which the reference signal should be transmitted include, for example, a time resource indicating the timing of transmission and a frequency resource used for transmitting the reference signal. The direction of transmission of the reference signal is from WD2 toward the moving object 3. Note that since WD2 is a tracking WD and recognizes the direction of the moving object 3, BS#1 can also notify WD2 of the target ID of the moving object 3 (determined in S3 of Figure 4) instead of notifying WD2 of the direction of transmission of the reference signal.

[0035] In S11, BS#1 notifies BS#2 of the radio resource to which WD2 will transmit the reference signal. In S12, WD2 transmits the reference signal according to the configuration in S10. At this time, WD2 transmits the reference signal using the transmit beam with the highest power in the direction toward the obstacle 3 among the multiple transmit beams used to transmit the signal. In S12, BS#2 receives the reference signal transmitted by WD2 and reflected by the moving object 3 with each of the multiple receive beams. The reference signal reflected by the moving object 3 can be determined based on the impulse response. In the following description, the receive beam of BS#2 that was able to receive the reference signal reflected by the moving object 3 and has the highest received power of the reference signal will be referred to as the reference receive beam.

[0036] In S13, BS#2 notifies BS#1 of the reception result A of the reference signal from WD2 on the reference receiving beam. Reception result A may include the received power Pa of the reference signal reflected by the moving object 3 at BS#2. Alternatively, reception result A may include the period τa from when WD2 transmits the reference signal until BS#2 receives the reference signal from WD2 on the reference receiving beam. If BS#2 does not receive the reference signal from WD2 on any of the receiving beams, in S13, BS#2 notifies BS#1 that it was not able to receive the reference signal from WD2. If BS#2 does not receive the reference signal from WD2, the received power Pa may be treated as 0 at BS#1. Also, if BS#2 does not receive the reference signal from WD2, the period τa may be treated as infinity at BS#1.

[0037] In S12, BS#1 also stores the reception result B of the reference signal transmitted by WD2 and reflected by the moving object 3. Reception result B may include the received power Pb of the reference signal reflected by the moving object 3 at BS#1. Alternatively, reception result B may include the period τb from when WD2 transmits the reference signal until BS#1 receives the reference signal from WD2. Since BS#1 is tracking the moving object 3, it can determine which of its multiple receiving beams receives the reference signal reflected by the moving object 3 most strongly. Therefore, in S12, BS#1 can receive the reference signal from WD2 with the previously determined receiving beam and determine the received power Pb or the period τb.

[0038] The processes in S10 to S13 are repeated. If multiple reference signal transmissions are configured in S10 and S11, the processes in S10 and S11 are performed only once, and then the processes in S12 and S13 are repeated the number of times the reference signal transmissions were configured. In the following explanation, the processes in S12 and S13 will be referred to as the "acquisition process". While repeating the acquisition process, BS#1 executes the determination process shown in Figure 7 in S14. The determination process determines whether or not to switch the second process to BS#2. In the flowchart in Figure 7, the reception result represents the received power.

[0039] In S50, BS#1 initializes counter k to 0. When it receives reception result A from BS#2 in S51, BS#1 determines in S52 whether Pa-Pb is greater than the first threshold (Th1). The first threshold can be a value of 0 or greater. If Pa-Pb is greater than the first threshold, BS#1 increases the value of counter k by 1 in S53. On the other hand, if Pa-Pb is not greater than the first threshold, BS#1 does not change the value of counter k.

[0040] Next, in S54, BS#1 determines whether the judgment in S52 has been performed K times, that is, whether the acquisition process has been performed K times. K is an integer of 2 or greater and is set in BS#1 in advance. If the number of times the acquisition process has been performed is less than K, BS#1 repeats the process from S51. On the other hand, when the number of times the acquisition process has been performed reaches K, BS#1 determines in S55 whether k / K is greater than or equal to the second threshold (Th2). The second threshold can be a value of 0.5 or greater. The second threshold is set in BS1 in advance. If k / K is not greater than the second threshold, BS#1 repeats the process from S50 without switching the second process to BS#2. On the other hand, if k / K is greater than the second threshold, BS#1 determines in S56 to switch the second process to BS#2 and terminates the process in Figure 7. In this case, in S15 of Figure 6, BS#1 instructs BS#2 to execute the second process for tracking the moving object 3.

[0041] Furthermore, if reception result A and reception result B indicate a period τ, the process in S52 determines whether τb-τa is greater than the first threshold, and if it is greater than the first threshold, the counter k is incremented by 1 in S53. The first threshold can be a value of 0 or greater.

[0042] In the flowchart in Figure 7, if k / K is not greater than the second threshold in S55, BS#1 was initialized to k=0 in S50. Therefore, if it is determined that the second process should not be switched to BS#2 after executing the acquisition process K times, the next decision on whether or not to switch the second process to BS#2 will be made after executing the acquisition process K more times.

[0043] Therefore, if, after executing the acquisition process K times, it is determined that the second process should not be switched to BS#2, then each time the acquisition process is executed thereafter, the system can be configured to determine whether or not to switch the second process to BS#2 based on the proportion of times in the past K determinations that Pa-Pb was greater than the first threshold. In other words, if the proportion of times in the most recent K acquisition processes that Pa-Pb was greater than the first threshold is greater than the second threshold, the system can be configured to switch the second process to BS#2.

[0044] Furthermore, BS#1 can be configured to determine the result in S55 as No if the value of Pa in the most recent L judgments is 0, even if the k / K value is greater than the second threshold. L is an integer from 1 to K. For example, if K=10, the second threshold=0.6, and L=1, even if Pa-Pb is greater than the first threshold in the reception results of the first 7 acquisition processes, the configuration can be configured not to switch to BS#2 if the value of Pa in the 10th acquisition process is 0.

[0045] Furthermore, although K is shown as an integer greater than or equal to 2 in the flowchart in Figure 7, K may also be 1. In this case, BS#1 determines that if Pa-Pb is greater than the first threshold in the reception result of one acquisition process, it will switch the second process to BS#2.

[0046] In the second process, BS1 sets the detection range based on the direction of movement of the obstacle being tracked, but it is also possible to configure it so that the detection range is not set. In this case, in the second process, BS1 transmits the second sensing signal with all of its transmitting beams, and the tracking WD attempts to receive the second sensing signal with all of its receiving beams.

[0047] As described above, when BS#1 determines that the moving object 3 being tracked is approaching BS#2 during the execution of the second process, it instructs the tracking WD to transmit an upward first signal, causing BS#2 to receive the first signal, and obtains the result as reception result A. BS#1 also obtains the result of receiving the first signal as reception result B. If reception result A satisfies predetermined conditions for reception result B, BS#1 determines that BS#2 is more suitable than BS#1 to perform the second process and instructs BS#2 to execute the second process. This configuration allows for effective switching of the communication device used for tracking the moving object.

[0048] <Communication device configuration> Figure 8 shows an example configuration of the communication device described as BS1 in the above embodiment. The transmitting unit 13 is configured to transmit signals to WD2, etc., using multiple transmitting beams. The receiving unit 14 is configured to receive signals from WD2 using multiple receiving beams. WD2 is also configured to transmit signals to BS1, etc., using multiple transmitting beams and to receive signals from BS1, etc., using multiple receiving beams.

[0049] The tracking unit 10 determines the moving object to be tracked and tracks it by executing the first and second processes. Specifically, it tracks the moving object by repeatedly transmitting a sensing signal and having the tracking WD receive the sensing signal.

[0050] The acquisition unit 11 causes the WD2 to transmit a first signal, such as an SRS reference signal, to the moving object being tracked, and performs an acquisition process to acquire the reception result A of the first signal from another communication device. In addition, the acquisition unit 11 may acquire the reception result B of the first signal received via the receiving beam during the acquisition process. Reception result A and reception result B may each include the received power of the first signal reflected by the moving object. Reception result A and reception result B may each include the period from when the WD2 transmits the first signal until the first signal reflected by the moving object is received.

[0051] The instruction unit 12, upon determining that reception result A meets predetermined criteria, instructs another communication device to track the moving object. For example, the instruction unit 12 can determine whether reception result A meets predetermined criteria by comparing reception result A with reception result B. The predetermined criteria may be as described with reference to Figure 7.

[0052] A communication device may be implemented as a single device. Alternatively, a communication device may consist of, for example, a radio unit (RU), a distributed unit (DU), and a central unit (CU), or a baseband unit (BBU) and a remote radio unit (RRU). In other words, a communication device may consist of multiple devices located in different locations. Furthermore, a communication device can be a DU. If a communication device is a DU, then the other communication device mentioned above may be another DU connected to the same CU.

[0053] Furthermore, the communication device may not be a base station device in a mobile communication network, but rather a wireless communication device such as a wireless LAN access point device. Also, the WD2 described in the above embodiment is not limited to a wireless device in a mobile communication network, but can be any wireless device that accesses a wireless communication device according to any wireless communication standard.

[0054] Furthermore, this disclosure provides a program executable on one or more processors. When executed on one or more processors of the device, the program includes instructions that cause the device to function as, for example, a communication device such as BS1 or a wireless device such as WD2. For example, when executed on one or more processors of the device, the program can cause the device to function as, for example, the tracking unit 10, acquisition unit 11, and instruction unit 12. Furthermore, this disclosure provides a non-temporary computer-readable storage medium storing the above program. Furthermore, this disclosure provides a method that follows the description using Figures 4, 6, and 7, etc. Furthermore, this disclosure provides a program for causing a device having one or more processors to execute the method, and a non-temporary computer-readable storage medium storing the program.

[0055] The invention is not limited to the embodiments described above, and various modifications and changes are possible within the scope of the gist of the invention.

[0056] With the above configuration, it is possible to switch the communication device used for tracking moving objects. Therefore, it becomes possible to contribute to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), "Build resilient infrastructure, promote sustainable industrialization and foster innovation." [Explanation of Symbols]

[0057] 10: Tracking unit, 11: Acquisition unit, 12: Instruction unit, 13: Transmitter unit, 14: Receiver unit

Claims

1. A communication device, A tracking means that tracks a moving object by repeatedly transmitting a sensing signal and having a wireless device receive it. Acquisition means includes a wireless device that transmits a first signal directed towards the moving object, and an acquisition process that acquires a first reception result of the first signal at another communication device, When the first reception result obtained from the other communication device satisfies a predetermined criterion, the instruction means instructs the other communication device to track the moving object, A communication device equipped with these features.

2. The acquisition means, in the acquisition process, acquires the second reception result of the first signal by the communication device, The communication device according to claim 1, wherein the instruction means determines whether the first reception result satisfies the predetermined criteria by comparing the first reception result with the second reception result.

3. The first reception result includes the first received power of the first signal reflected by the moving object at the other communication device. The second reception result includes the second received power at the communication device of the first signal reflected by the moving object. The communication device according to claim 2, wherein the predetermined criterion is satisfied when the value obtained by subtracting the second received power from the first received power is greater than a first threshold of 0 or more.

4. The first reception result includes a first period from when the wireless device transmits the first signal until the other communication device receives the first signal reflected by the moving object. The second reception result includes a second period from the time the wireless device transmits the first signal until the communication device receives the first signal reflected by the moving object. The communication device according to claim 2, wherein the predetermined criterion is satisfied if the value obtained by subtracting the first period from the second period is greater than a first threshold of 0 or more.

5. The acquisition means repeatedly performs the acquisition process, The first reception result includes the first received power of the first signal reflected by the moving object at the other communication device. The second reception result includes the second received power at the communication device of the first signal reflected by the moving object. The communication device according to claim 2, wherein the predetermined criteria are satisfied if, in the acquisition process a predetermined number of times in the past, the number of times the value obtained by subtracting the second received power from the first received power is greater than or equal to a first threshold of 0 is greater than the number of times the value obtained is greater than or equal to a second threshold.

6. The acquisition means repeatedly performs the acquisition process, The first reception result includes a first period from when the wireless device transmits the first signal until the other communication device receives the first signal reflected by the moving object. The second reception result includes a second period from the time the wireless device transmits the first signal until the communication device receives the first signal reflected by the moving object. The communication device according to claim 2, wherein the predetermined criteria are satisfied if, in the acquisition process a predetermined number of times in the past, the number of times the value obtained by subtracting the first period from the second period is greater than or equal to a first threshold of 0 is greater than the second threshold.

7. The communication device according to claim 5 or 6, wherein even if the number of times greater than the first threshold is greater than the second threshold, the predetermined criterion is not met if the other communication device has not received the first signal reflected by the moving object during the acquisition process for a fixed number of times in the immediate vicinity.

8. The communication device according to any one of claims 1 to 6, wherein the first signal is an upward reference signal.

9. The communication device according to claim 8, wherein the first signal is a sounding reference signal.

10. The communication device according to any one of claims 1 to 6, wherein the communication device and the other communication device are base station devices.

11. The communication device according to any one of claims 1 to 6, wherein the communication device and the other communication device are other distributed units (DUs) connected to the same central unit (CU).

12. A program that, when executed on one or more processors of a device having one or more processors, causes the device to function as a communication device according to any one of claims 1 to 6.

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