Communication controller and mobile relay device

Abstract

To provide a communication controller and a mobile relay device for appropriately controlling a position of the mobile relay device.SOLUTION: A radio communications system for covering a non-sensitive area and an area in which satisfactory radio communication is impossible by using a relay device comprises a mobile relay device for relaying radio communication between a base station device and a terminal device at a position to which the mobile relay device is moved. The mobile relay device acquires radio quality information from respective terminal devices, acquires positional information from a reference terminal device, estimates a position of a target terminal device, estimates a position of the reference terminal device, compares the estimated position of the reference terminal device with an acquired actual measurement position to calculate a difference between the estimated positions, calculates an error of the estimated position of the target terminal device, corrects the estimated position of the target terminal device by using the error of the estimated position of the target terminal device, estimates average transmission rates of the target terminal device and the reference terminal device for each movement destination candidate position, decides a movement position, and moves to the decided movement position.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a communication control device and a mobile relay device. [Background technology]

[0002] Although millimeter-wave wireless communication enables high-capacity communication using a wide bandwidth, it can suffer from significant losses due to propagation loss and obstruction. Therefore, to improve communication quality, wireless communication systems equipped with mobile relay stations (RS) have been attracting attention. The RS is mounted on, for example, a drone or other unmanned aerial vehicle (UAV), and by moving to an appropriate location, it relays communications between terminal devices located in areas where radio waves from a base station cannot reach directly.

[0003] Techniques relating to relay devices are described in the following documents, for example. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-83243 [Patent Document 2] Japanese Patent Application Publication No. 2023-119340 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it is difficult to move the RS to an appropriate position. For example, if the RS is far from the terminal device, sufficient wireless communication quality may not be maintained.

[0006] Therefore, one disclosure can provide a communication control device that appropriately controls the position of an RS. [Means for solving the problem]

[0007] A control device controls a mobile relay device that relays wireless communication between a base station device and a terminal device at a moved position, and includes: an acquisition unit that causes the mobile relay device to acquire first wireless quality information including information about wireless quality in a first terminal device, second wireless quality information including information about wireless quality in a second terminal device, and measured position information including information about the measured position of the second terminal device; an estimation unit that calculates a first estimated position of the first terminal device using the first wireless quality information and calculates a second estimated position of the second terminal device using the second wireless quality information; and a control unit that considers a difference between the second estimated position and the measured position to be an error, calculates a first corrected position by correcting the first estimated position using the error, determines a moving position according to the first corrected position and the measured position, and moves the mobile relay device to the moving position. [Effects of the Invention]

[0008] One disclosure is that the position of the RS can be appropriately controlled. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a wireless communication system 10. As shown in FIG. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of the relay device 300. As shown in FIG. [Figure 3] FIG. 3 is a diagram showing an example of the position to which the relay device 300 is moved. [Figure 4] FIG. 4 is a diagram showing an example of a processing flowchart of the position movement processing S100. [Figure 5] FIG. 5 is a diagram showing an example of a processing flowchart of the estimated position error calculation process S200. [Figure 6] FIG. 6 is a diagram showing an example of a processing flowchart of the movement position determination process S300. DETAILED DESCRIPTION OF THE INVENTION

[0010] [First embodiment] A first embodiment will be described.

[0011] <About the wireless communication system 10> 1 is a diagram showing an example of the configuration of a wireless communication system 10. The wireless communication system 10 includes terminal devices 100-1 and 100-2 (hereinafter sometimes referred to as terminal devices 100), a relay device 300, and a base station device 200. The wireless communication system 10 is a system that uses a relay device to cover blind areas (areas where wireless communication is not possible) and areas where good wireless communication is not possible.

[0012] The terminal device 100 is a communication device, such as a tablet terminal or a smartphone, that is wirelessly connected to the base station device 200 and performs wireless communication. The terminal device 100 may also be wirelessly connected to the relay device 300 and perform wireless communication. In FIG. 1, the terminal devices 100-1 and 100-2 perform wireless communication with the relay device 300.

[0013] The base station device 200 is a communication device, such as an eNodeB or a gNodeB, that is wirelessly connected to and performs wireless communication with the terminal device 100. The base station device 200 is also wirelessly connected to and performs wireless communication with the relay device 300. The base station device 200 may also control the relay function performed by the relay device 300.

[0014] The relay device 300 is a device, such as an RS, that is wirelessly connected to the terminal device 100 and the base station device 200 and performs wireless communication. The relay device 300 has a relay function of relaying wireless communication between the terminal device 100 and the base station device 200. In its relay function, the relay device 300 transmits a signal received from the terminal device 100 to the base station device 200 and transmits a signal received from the base station device 200 to the terminal device 100.

[0015] The relay device 300 can be moved as needed, and is mounted on a UAV such as a drone. At a predetermined timing, the relay device 300 moves to the vicinity of the terminal device 100 in order to communicate wirelessly with the terminal device 100 that cannot communicate wirelessly with the base station device 200 (the radio waves cannot reach the terminal device 100). In FIG. 1, the relay device 300 moves to a position where it can communicate wirelessly with the terminal devices 100-1 and 100-2.

[0016] The relay device 300 determines a location to which the relay device 300 should move depending on the location of the terminal device 100. The relay device 300 acquires location information of the terminal device 100 or estimates the location of the terminal device 100, calculates a location where wireless communication with the terminal device 100 is possible, and determines a location to which the relay device 300 should move. When estimating the location of the terminal device 100, the relay device 300 estimates an error between the estimated location and the actual location, and corrects the estimated location using the error.

[0017] <Configuration Example of Relay Device 300> 2 is a diagram illustrating a configuration example of the relay device 300. The relay device 300 is a communication device having a CPU (Central Processing Unit) 310, a storage 320, a memory 330, a first communication circuit 350, and a second communication circuit 351, and is a communication control device (mobile relay device) that controls wireless communication (relay of wireless communication).

[0018] The storage 320 is an auxiliary storage device that stores programs and data, such as a flash memory, a hard disk drive (HDD), or a solid state drive (SSD). The storage 320 stores a communication relay control program 321 and a position movement program 322.

[0019] The memory 330 is an area into which the programs stored in the storage 320 are loaded. The memory 330 may also be used as an area in which the programs store data.

[0020] The first communication circuit 350 is a circuit that wirelessly connects to and communicates with the base station device 200. The first communication circuit 350 transmits signals received from the terminal device 100 to the base station device 200, and receives signals to be transmitted from the base station device 200 to the terminal device 100.

[0021] The second communication circuit 351 is a circuit that wirelessly connects to and communicates with the terminal device 100. The second communication circuit 351 transmits signals received from the base station device 200 to the terminal device 100, and receives signals to be transmitted from the terminal device 100 to the base station device 200. If there are multiple terminal devices 100, multiple second communication circuits 351 are installed. Furthermore, one second communication circuit 351 may be capable of communicating with multiple terminal devices 100.

[0022] The CPU 310 is a processor that loads a program stored in the storage 320 into the memory 330, executes the loaded program, configures each unit, and realizes each process.

[0023] The CPU 310 executes the communication relay control program 321 to establish a control unit and perform communication relay control processing. The communication relay control processing is processing for relaying communication between the base station device 200 and the terminal device 100. In the communication relay control processing, the relay device 300 transmits, for example, a signal received from the base station device 200 to the terminal device 100, and transmits a signal received from the terminal device 100 to the base station device 200.

[0024] By executing the position movement program 322, the CPU 310 configures an acquisition unit, an estimation unit, and a control unit, and performs position movement processing. The position movement processing is processing for determining a movement position of the relay device 300 and moving to the determined movement position. The relay device 300 acquires the position information of the terminal device 100, estimates the position of the terminal device 100 for which position information cannot be acquired, calculates (estimates) an error in the estimated position, and determines a movement position based on the estimated position that takes the error into consideration.

[0025] The CPU 310 executes the estimated position error calculation module 3221 included in the position movement program 322 to construct an estimation unit and a control unit and perform an estimated position error calculation process. The estimated position error calculation process is a process for calculating an error in the estimated position of the terminal device 100. The error is indicated by a distance, and is calculated (estimated) from, for example, the difference between the actual position and the estimated position of another terminal device 100.

[0026] The CPU 310 executes the movement position determination module 3222 included in the position movement program 322 to construct a control unit and perform movement position determination processing. The movement position determination processing is processing for determining the movement position of the relay device 300 according to the actual position and estimated position of the terminal device 100. The relay device 300 corrects the estimated position using an error, and determines the movement position so that communication is possible no matter where the terminal device 100 is located within a range including the error.

[0027] <Position movement processing> The location movement process S100 of the relay device 300 will now be described. Fig. 3 is a diagram showing an example of the location of the relay device 300. In Fig. 3, it is assumed that the relay device 300 cannot acquire terminal location information of the terminal device 100-1, but can acquire terminal location information of the terminal device 100-2. Also, in Fig. 3, terminal device 100-1-P indicates the estimated location of the terminal device 100-1, and terminal device 100-2-P indicates the estimated location of the terminal device 100-2.

[0028] The relay device 300 considers that the terminal device 100-1 exists (may exist) within a range R100 with the estimated location of the terminal device 100-1 as the center and the error as the radius, and determines a location that includes the range R100 within the cell C300 of the relay device 300 (where the relay device 300 is located). The relay device 300 considers, for example, the difference between the measured location of the terminal device 100-2 and the estimated location, terminal device 100-2-P, as an error in the estimated location of the terminal device 100-1. As a result, as shown in FIG. 3, even when the actual location of the terminal device 100-1 is far from the estimated location, particularly when it is far outside the cell C300, the terminal device 100-1 can be located within the cell C300.

[0029] 4 is a diagram showing an example of a processing flowchart of the location movement processing S100. In the location movement processing S100, the relay device 300 acquires wireless quality information from each terminal device 100 (S100-1). Each terminal device 100 indicates, for example, one or more terminal devices 100 that communicate via the relay device 300. The wireless quality information is information related to the wireless quality of the terminal device 100, and includes, for example, received power, frame error rate, throughput, etc. The relay device 300 may acquire the wireless quality information directly by wirelessly communicating with the terminal device 100, or may acquire the wireless quality information from (via) another relay device 300 or a base station device 200.

[0030] The relay device 300 acquires location information from a reference terminal device (S100-2). The reference terminal device is, for example, a terminal device that actually measures location information, such as the terminal device 100-2 in Fig. 3. The relay device 300 may acquire the location information directly by wireless communication with the reference terminal device, or may acquire the location information from (via) another relay device 300 or the base station device 200.

[0031] The relay device 300 estimates the location of the target terminal device (S100-3). The target terminal device is, for example, a terminal device for which location information could not be acquired (no actual measurement has been performed), such as the terminal device 100-1 in Fig. 3. The relay device 300 estimates the location of the terminal device 100 using, for example, wireless quality information of the target terminal device.

[0032] The relay device 300 executes an estimated position error calculation process (S200). The estimated position error calculation process S200 is a process for calculating an error (a distance by which there is a possibility of deviation) in the estimated position of the target terminal device.

[0033] 5 is a diagram showing an example of a processing flowchart of the estimated position error calculation process S200. In the estimated position error calculation process S200, the relay device 300 estimates the position of the reference terminal device (S200-1). The relay device 300 estimates the position of the reference terminal device using radio quality information of the reference terminal device. In FIG. 3, the relay device 300 calculates terminal device 100-1-P, which is the estimated position of terminal device 100-1.

[0034] The relay device 300 compares the estimated position of the reference terminal device with the acquired measured position, and calculates the difference between the estimated positions (S200-2). The relay device 300 calculates the difference as the distance between the two position coordinates.

[0035] Then, the relay device 300 calculates the error in the estimated position of the target terminal device (S200-3) and ends the process. The relay device 300 regards the difference of the reference terminal device calculated in process S200-2 as the error of the target terminal device, for example.

[0036] 4, the relay device 300 executes a movement position determination process (S300). The movement position determination process S300 is a process for determining a movement position of the relay device 300.

[0037] 6 is a diagram showing an example of a processing flowchart of the moving position determination process S300. In the moving position determination process S300, the relay device 300 corrects the estimated position of the target terminal device using an error in the estimated position of the target terminal device (S300-1). For example, the relay device 300 regards a position that has moved (distant) from the estimated position of the target terminal device by the distance of the error in a direction away from the reference terminal device as the corrected estimated position (corrected estimated position). Furthermore, the relay device 300 may regard, for example, a circular range (for example, range R100 in FIG. 3) centered on the estimated position of the target terminal device and with the error as the radius as the corrected estimated position.

[0038] The relay device 300 estimates the average transmission rates of the target terminal device and the reference terminal device for each candidate destination position (S300-2). A plurality of candidate destination positions are set, for example, according to the actual measured position of the reference terminal device and the estimated position of the target terminal device (which may be a corrected estimated position). The relay device 300 estimates the average transmission rates of the target terminal device and the reference terminal device for each candidate position. Note that the target terminal device may specify one corrected estimated position, or the average transmission rates may be estimated for multiple positions (for example, several points on the circumference of the range R100 in FIG. 3). Note that the average transmission rate is just an example, and received power, throughput, etc. may also be estimated.

[0039] The relay device 300 determines the movement position (S300-3) and ends the process. The relay device 300 selects a movement position from the candidate positions so that the average transmission rate estimated in process S300-2 is appropriate (for example, so that the average value of each terminal device is the highest or the average transmission rate of the terminal device with the lowest average transmission rate is not below a threshold).

[0040] Returning to the processing flowchart of FIG. 4, the relay device 300 moves to the determined movement position (S100-4), and the processing ends.

[0041] The process up to determining the movement position in the position movement process S100 may be performed by, for example, the base station device 200 or a control device connected to a higher level of the base station device 200. In this case, the base station device 200 or the control device becomes a communication control device.

[0042] Furthermore, when the terminal device 100 is wirelessly connected to the base station device 200, the wireless quality information and the terminal location information may be acquired by the base station device 200. In this case, the base station device 200 transmits the acquired information to the relay device 300.

[0043] Furthermore, when the control device or base station device 200 executes the position movement process S100, the process S100-4 can be interpreted as "moving the relay device to the determined position."

[0044] [Other embodiments] In the first embodiment, there was one reference terminal device (only the terminal device 100-2 in FIG. 1). When there are multiple reference terminal devices, the relay device 300 calculates the error using the following method.

[0045] In the first method, the relay device 300 regards the average value of the difference between the measured position and the estimated position of each of all the reference terminal devices as the error of the target terminal device.

[0046] In the second method, the relay device 300 weights the difference between the measured position and the estimated position of each of all reference terminal devices, and regards the average value of the weighted differences as the error of the target terminal device.

[0047] In the third method, the relay device 300 selects one or more differences between the measured location and the estimated location of each of all reference terminal devices in order of priority, and considers the average value (or weighted average value) of these as the error of the target terminal device. Note that the priority is determined, for example, in descending order of weight. Furthermore, the priority may be determined, for example, according to the accuracy (performance) of measuring the location of the reference terminal device (obtained from GPS, etc.).

[0048] The weight is set to a larger value, for example, the closer the distance between the estimated location of the target terminal device and the actually measured location of the reference terminal device. Also, the weight is set to a larger value when the reference terminal device that measured the wireless quality information is wirelessly connected to the relay device 300 than when it is wirelessly connected to the base station device 200 or another relay device 300.

[0049] The following is a summary as follows:

[0050] (Appendix 1) A control device that controls a mobile relay device that relays wireless communication between a base station device and a terminal device at a moved position, an acquisition unit that causes the mobile relay device to acquire first wireless quality information including information about wireless quality in a first terminal device, second wireless quality information including information about wireless quality in a second terminal device, and actual measured location information including information about an actual measured location of the second terminal device; an estimation unit that calculates a first estimated position of the first terminal device using the first wireless quality information and calculates a second estimated position of the second terminal device using the second wireless quality information; a control unit that regards a difference between the second estimated position and the actual measured position as an error, calculates a first corrected position by correcting the first estimated position using the error, determines a movement position according to the first corrected position and the actual measured position, and moves the mobile relay device to the movement position; A control device having:

[0051] (Appendix 2) The moving position is a position where both the first corrected position and the actual measured position are included in a communication area where wireless communication with the mobile relay device can be performed. 2. The communications control device of claim 1.

[0052] (Appendix 3) the first corrected position is a position that is separated from the first estimated position by the error in a direction opposite to the actual measured position, The moving position is a position where both the first corrected position and the actual measured position are included in a communication area where wireless communication with the mobile relay device can be performed. 2. The communications control device of claim 1.

[0053] (Appendix 4) the first corrected position is a range of a circle having the first estimated position as a center and the error as a radius, The moving position is a position where both the entire range of the circle and the measured position are included in a communication area where wireless communication with the mobile relay device can be performed. 2. The communications control device of claim 1.

[0054] (Appendix 5) When a plurality of the second terminal devices are present, the control unit regards an average value of differences between the second estimated positions and the measured positions of the plurality of second terminal devices as the error. 2. The communications control device of claim 1.

[0055] (Appendix 6) When a plurality of the second terminal devices are present, the control unit weights the difference between the second estimated position and the measured position of each of the plurality of second terminal devices, and regards the average value of the weighted differences as the error. 2. The communications control device of claim 1.

[0056] (Appendix 7) The weight has a larger value as the distance between the measured position of the second terminal device and the first estimated position is shorter. 7. The communications control device of claim 6.

[0057] (Appendix 8) The weight is a larger value when the second terminal device and the first terminal device are wirelessly connected to the same communication device than when the second terminal device and the first terminal device are wirelessly connected to different communication devices. 7. The communications control device of claim 6.

[0058] (Appendix 9) a second acquisition unit that acquires first wireless quality information including information about wireless quality in a first terminal device, second wireless quality information including information about wireless quality in a second terminal device, and actual measured location information including information about the actual measured location of the second terminal device; a second estimation unit that calculates a first estimated position of the first terminal device using the first wireless quality information and calculates a second estimated position of the second terminal device using the second wireless quality information; a second control unit that regards a difference between the second estimated position and the actual measured position as an error, calculates a first corrected position by correcting the first estimated position using the error, determines a movement position according to the first corrected position and the actual measured position, and moves to the movement position; A mobile relay device having the same. [Explanation of symbols]

[0059] 10: Wireless communication system 100: Terminal device 200:Base station equipment 300: Relay device 310: CPU 320: Storage 321: Communication relay control program 322: Position movement program 3221: Estimated position error calculation module 3222: Movement position determination module 330: Memory 350: First communication circuit 351: Second communication circuit

Claims

1. A control device that controls a mobile relay device that relays wireless communication between a base station device and a terminal device at a moved position, an acquisition unit that causes the mobile relay device to acquire first wireless quality information including information on wireless quality in a first terminal device, second wireless quality information including information on wireless quality in a second terminal device, and actual measured location information including information on an actual measured location of the second terminal device; an estimation unit that calculates a first estimated position of the first terminal device using the first wireless quality information and calculates a second estimated position of the second terminal device using the second wireless quality information; a control unit that regards a difference between the second estimated position and the actual measured position as an error, calculates a first corrected position by correcting the first estimated position using the error, determines a movement position according to the first corrected position and the actual measured position, and moves the mobile relay device to the movement position; A communication control device having:

2. The moving position is a position where both the first corrected position and the actual measured position are included in a communication area where wireless communication with the mobile relay device can be performed. The communication control device according to claim 1.

3. the first corrected position is a position that is separated from the first estimated position by the error in a direction opposite to the actual measured position, The moving position is a position where both the first corrected position and the actual measured position are included in a communication area where wireless communication with the mobile relay device can be performed. The communication control device according to claim 1.

4. the first corrected position is a range of a circle having the first estimated position as a center and the error as a radius, The moving position is a position where both the entire range of the circle and the measured position are included in a communication area where wireless communication with the mobile relay device can be performed. The communication control device according to claim 1.

5. When a plurality of the second terminal devices are present, the control unit regards an average value of differences between the second estimated positions and the measured positions of the plurality of second terminal devices as the error. The communication control device according to claim 1.

6. When a plurality of the second terminal devices are present, the control unit weights the difference between the second estimated position and the measured position of each of the plurality of second terminal devices, and regards the average value of the weighted differences as the error. The communication control device according to claim 1.

7. The weight has a larger value as the distance between the measured position of the second terminal device and the first estimated position is shorter.

7. The communication control device according to claim 6.

8. The weight is a larger value when the second terminal device and the first terminal device are wirelessly connected to the same communication device than when the second terminal device and the first terminal device are wirelessly connected to different communication devices.

7. The communication control device according to claim 6.

9. a second acquisition unit that acquires first wireless quality information including information on wireless quality in a first terminal device, second wireless quality information including information on wireless quality in a second terminal device, and actual measured location information including information on an actual measured location of the second terminal device; a second estimation unit that calculates a first estimated position of the first terminal device using the first wireless quality information and calculates a second estimated position of the second terminal device using the second wireless quality information; a second control unit that regards a difference between the second estimated position and the actual measured position as an error, calculates a first corrected position by correcting the first estimated position using the error, determines a movement position according to the first corrected position and the actual measured position, and moves to the movement position; A mobile relay device having the same.

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