Communication device, communication system, communication method, and program

Abstract

A communication device having directivity, the communication device comprising: a reception unit that receives radio waves from a base station, and stores an incoming wave direction and position information of the communication device in a database; and a processing unit that predicts the incoming wave direction from a handover destination base station for the communication device on the basis of past information acquired from the database, and controls the directivity of the communication device on the basis of a prediction result.

Description

Communication device, communication system, communication method, and program

[0001] The present invention relates to a technique for controlling the directivity of an antenna.

[0002] In a wireless communication system for mobile terminals, such as LTE or 5G, a handover occurs when the terminal moves from one cell to another.

[0003] In wireless communication systems such as LTE and 5G, terminals do not have sharp directivity, so they can receive signals from surrounding base stations (which may also be called adjacent base stations). The terminal reports information such as the received power of signals received from the surrounding base stations to the base station (serving base station), and the base station determines whether to have the terminal perform a handover based on the information received from the terminal.

[0004] Regarding the control of directivity, after the handover is completed, for example, the base station receives radio waves from the terminal, and the base station sets the directivity for the terminal.

[0005] Patent Publication No. 2020-92386

[0006] 3GPP TR 38.912 V17.0.0 (2022-03)

[0007] Future wireless communication systems are expected to use high-frequency radio waves with large propagation losses. To utilize these high-frequency radio waves, it is expected that not only base stations but also terminals will have strong directivity.

[0008] A terminal with a sharp directivity is expected to be unable to properly receive radio waves from surrounding base stations (including the target base station for handover).Furthermore, unless an appropriate directivity is set, a terminal with a sharp directivity is expected to be unable to properly communicate with the target base station for handover.

[0009] Therefore, a terminal with a sharp directivity needs to determine a target base station for handover without communicating with the target base station in advance and then direct its directivity in the direction of the target base station.However, this operation was not possible with conventional technology.

[0010] The present invention has been made in consideration of the above points, and aims to provide a technology that enables a terminal to set a directivity suitable for communication with a target base station for handover without communicating with the target base station in advance.

[0011] According to the disclosed technology, there is provided a directional communication device comprising: a receiving unit that receives radio waves from a base station and stores the direction of the incoming wave and location information of the communication device in a database; and a processing unit that predicts the direction of the incoming wave from a handover destination base station of the communication device based on past information acquired from the database, and controls the directivity of the communication device based on the prediction result.

[0012] The disclosed technology provides a technology that enables a terminal to set a directivity suitable for communication with a target base station for handover without communicating with the target base station in advance.

[0013] 1 is a diagram illustrating an example of the configuration of a communication system. FIG. 2 is a diagram illustrating an example of the configuration of a communication system. FIG. 3 is a flowchart illustrating the operation of a terminal 100. FIG. 4 is a diagram illustrating an example 1 of a method for constructing a performance value DB 20. FIG. 5 is a diagram illustrating an example 2 of a method for constructing a performance value DB 20. FIG. 6 is a diagram illustrating an example 3 of a method for constructing a performance value DB 20. FIG. 7 is a diagram illustrating a method for predicting the direction of an incoming wave. FIG. 8 is a diagram illustrating an example of the hardware configuration of a terminal 100.

[0014] Hereinafter, an embodiment of the present invention (the present embodiment) will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment. In the following description, handover may be referred to as HO.

[0015] (Outline of embodiment, example system configuration) In this embodiment, when a terminal with high directivity performs a handover, it determines in which direction its directivity needs to be pointed after the handover based on the direction of arrival of radio waves (direction of arrival wave) from the currently connected base station (base station in its coverage area) and information stored in a database (DB).

[0016] In other words, the terminal can form an optimal beam pattern for communicating with the target base station based on the direction of the incoming wave from the currently connected base station and DB information, without communicating with the target base station in advance.

[0017] An example of the configuration of a communication system for realizing the above operation is shown in Fig. 1. As shown in Fig. 1, this communication system includes a receiver 10 having an antenna 15, a performance value DB 20, a handover destination predictor 30, an arrival wave direction predictor 40, and a directivity controller 50.

[0018] The receiver 10 having the antenna 15, the performance value DB 20, the handover destination prediction unit 30, the arrival wave direction prediction unit 40, and the directivity control unit 50 may be provided anywhere, but in this embodiment, it is assumed that the receiver 10 having the antenna 15, the handover destination prediction unit 30, the arrival wave direction prediction unit 40, and the directivity control unit 50 are provided in a terminal 100 (e.g., a smartphone), and the performance value DB 20 is provided on a server on a network 300 (e.g., a computing resource in the cloud). A system configuration based on this assumption is shown in FIG. 2. The terminal 100 may also be called a communication device.

[0019] The functions of each unit in the configuration shown in FIG. 1 are outlined below.

[0020] The receiver 10 receives radio waves (signals) from a base station using an antenna 15. The antenna 15 is assumed to have a sharp directivity. The performance value DB 20 stores, for each base station, information indicating the location of a terminal within the range of the base station and the direction from which the radio waves arrive for the terminal at that location.

[0021] The handover destination prediction unit 30 predicts a handover destination base station from current handover candidates (for example, a plurality of surrounding base stations) and past performance values ​​acquired from the performance value DB 20 .

[0022] The arrival wave direction prediction unit 40 predicts from which direction the radio waves from the HO destination base station will arrive (in which direction the directivity of the antenna 15 should be directed) based on the position of the terminal 100 and information obtained from the performance value DB 20.

[0023] The directivity control unit 50 controls the directivity of the antenna 15 based on the result of the arrival wave direction prediction by the arrival wave direction prediction unit 40 .

[0024] (Operation of Terminal 100) In the following description, the terminal 100 is assumed to include "a receiving unit 10 having an antenna 15, a handover destination prediction unit 30, an arrival wave direction prediction unit 40, and a directivity control unit 50." However, it is not essential that the terminal 100 include all of "a receiving unit 10 having an antenna 15, a handover destination prediction unit 30, an arrival wave direction prediction unit 40, and a directivity control unit 50." For example, the handover destination may be specified externally without including the handover destination prediction unit 30. Furthermore, the "handover destination prediction unit 30, an arrival wave direction prediction unit 40, and a directivity control unit 50" may be referred to as a "processing unit."

[0025] The receiver 10 in the terminal 100 receives a signal (or data) from a base station using the antenna 15, thereby acquiring the direction of arrival of the radio wave (direction of incoming waves). The receiver 10 also acquires location information of the terminal 100. The receiver 10 transmits to the performance value DB 20, for example, "information about the connected base station (e.g., cell ID, base station ID, etc.), the direction of incoming waves, location information of the terminal 100, time information when the direction of incoming waves and location information were acquired, and information for identifying the terminal 100." The performance value DB 20 stores this information. Details of the information stored in the performance value DB 20 will be described later.

[0026] Here, the receiving unit 10 is described as having the function of transmitting information to the actual value DB 20, but the transmission of information to the actual value DB 20 may also be performed by a functional unit in the terminal 100 other than the receiving unit 10.

[0027] In this embodiment, it is assumed that a plurality of terminals (terminals having the same functions as terminal 100) exist under each of a plurality of base stations, and each terminal stores information such as the direction of arrival waves and location information in actual value DB 20. Each terminal may store information in actual value DB 20 at predetermined time intervals, or may store information in actual value DB 20 immediately before and after handover, or may store information in actual value DB 20 at other times.

[0028] Next, the operation of the terminal 100 during handover will be described with reference to the flowchart of FIG.

[0029] <S101 (Step 101)> For example, assume that the terminal 100 is located near the edge of the cell in which it is located. In S101, when the handover destination prediction unit 30 determines that a handover is necessary based on, for example, the location information of the terminal 100 or the received power of a signal received from a connected base station (for example, the received power is equal to or less than a threshold), the handover destination base station is predicted from one or more surrounding base stations.

[0030] The handover destination prediction unit 30 obtains, for example, from the performance value DB 20, the performance of the handover destination base station of the terminal that was present at the current location of the terminal 100, and predicts the handover destination base station based on the performance.

[0031] Furthermore, if the receiver 10 can receive signals (such as synchronization signals) from one or more neighboring base stations, the receiver 10 may predict the base station to which the handover is to be performed by using information on the received power and the above-mentioned performance data. For example, if the performance data indicates that multiple neighboring base stations are candidates for the handover destination, the receiver 10 may predict the neighboring base station with the highest received power as the handover destination base station.

[0032] <S102, S103> In S102, the arrival wave direction predictor 40 predicts the direction from which the radio waves from the handover destination base station predicted in S101 will arrive. The prediction method will be described in detail later.

[0033] In S103, the directivity control unit 50 controls the directivity of the antenna 15 of the terminal 100 based on the prediction result in S102.

[0034] Below, examples of a method for constructing the performance value DB 20 and a method for predicting the direction of an incoming wave will be described in detail. Examples 1 to 3 will be described for the method for constructing the performance value DB 20, and examples a to b will be described for the method for predicting the direction of an incoming wave. In the description of the method for constructing the performance value DB 20, the operation of the terminal 100 is described, but the other terminals also perform similar operations. It is also possible to implement a combination of examples 1 to 3, and it is also possible to implement a combination of examples a to b.

[0035] Furthermore, when the terminal 100 operates to refer to the information in the actual value DB 20, the terminal 100 may refer to the information constructed in Example 1, the information constructed in Example 2, or the information constructed in Example 3.

[0036] (Example 1 of Method for Constructing Performance Value DB 20) First, a description will be given of Example 1 of the method for constructing performance value DB 20. In Example 1, terminal 100 stores the acquired direction of arrival wave and the position information of terminal 100 in performance value DB 20 as is.

[0037] 4 shows an image of information storage in the performance value DB 20 in Example 1. In the example of FIG. 4, the terminal 100A under the control of the base station 200A stores the direction of arrival wave and the position information of the terminal 100A that it has acquired itself in the performance value DB 20. The terminal 100B under the control of the base station 200B stores the direction of arrival wave and the position information of the terminal 100B that it has acquired itself in the performance value DB 20.

[0038] For example, Example 1 is used when the actual value DB 20 can store a huge amount of data, such as when abundant cloud resources are available. In Example 1, the amount of data may be huge, but detailed information can be reflected in the prediction.

[0039] (Example 2 of Method for Constructing Actual Value DB 20) Next, a description will be given of Example 2 of the method for constructing the actual value DB 20. In Example 2, the terminal 100 stores in the actual value DB 20 information obtained by averaging (or median-processing) the acquired direction of arrival waves and location information over a certain time interval (for example, T).

[0040] A simple example will be used for explanation. For example, suppose that terminal 100 acquires three directions of arrival waves D1, D2, and D3 within a time length T and acquires three pieces of location information P1, P2, and P3. Assume that D and P are each a vector. In this case, if averaging is to be performed, terminal 100 stores (D1+D2+D3) / 3 and (P1+P2+P3) / 3 in actual value DB 20 as information for that time interval.

[0041] Fig. 5 shows an image of information storage in the performance value DB 20 in Example 2. In the example of Fig. 5, terminal 100A under the control of base station 200A stores information obtained by performing time averaging (or median processing) on ​​the direction of arrival wave and location information of terminal 100A that it has acquired, in performance value DB 20. Terminal 100B under the control of base station 200B stores information obtained by performing time averaging (or median processing) on ​​the direction of arrival wave and location information of terminal 100A that it has acquired, in performance value DB 20.

[0042] Example 2 is expected to be applied to devices that move slowly, such as devices carried by pedestrians. In Example 2, it is possible to process outliers and instantaneous fluctuations, summarize temporal fluctuations, and reduce the amount of data before storing it.

[0043] (Example 3 of Method for Constructing Actual Value DB 20) Next, a description will be given of Example 3 of the method for constructing the actual value DB 20. In Example 3, the terminal 100 stores in the actual value DB 20 information obtained by averaging (or median-processing) the acquired direction of arrival waves and position information in a certain space (i.e., multiple positions).

[0044] A simple example will be used for explanation. For example, assume that terminal 100 acquires three directions of arrival waves D1, D2, and D3 within an area of ​​a predetermined size, and acquires three pieces of location information P1, P2, and P3. Assume that D and P are each a vector. In this case, if averaging is performed, terminal 100 stores (D1 + D2 + D3) / 3 and (P1 + P2 + P3) / 3 in actual value DB 20 as information for that area.

[0045] Fig. 6 shows an image of information storage in the performance value DB 20 in Example 3. In the example of Fig. 6, the terminal 100A under the control of the base station 200A stores information obtained by performing spatial averaging (or median processing) on ​​the direction of arrival wave and the position information of the terminal 100A that it has acquired, in the performance value DB 20. The terminal 100B under the control of the base station 200B stores information obtained by performing spatial averaging (or median processing) on ​​the direction of arrival wave and the position information of the terminal 100A that it has acquired, in the performance value DB 20.

[0046] Example 3 is expected to be applied to terminals that move at high speed, such as terminals mounted on vehicles, etc. In Example 3, it is possible to process outliers and instantaneous fluctuations, summarize time fluctuations, and then reduce the amount of data before saving.

[0047] (Prediction of Direction of Arrival Wave: Example a) Next, prediction of direction of arrival wave will be described. In both examples a and b, the explanation of prediction of direction of arrival wave assumes a situation in which the terminal 100 performs handover from the cell of the base station 200A to the cell of the base station 100B, as shown in FIG. 7 .

[0048] First, example a will be described. In example a, the arrival wave direction prediction unit 40 of the terminal 100 predicts the arrival wave direction from the handover destination base station 200B based on the arrival wave direction from the base station with which the terminal 100 is currently communicating (the handover source base station 200A). An example of a specific processing operation is as follows. Here, it is assumed that the receiving unit 10 can receive signals from surrounding base stations.

[0049] A receiver 10 of a terminal 100 located in the cell of the base station 200A receives signals (synchronization signals, etc.) from the base station 200A and a plurality of surrounding base stations.

[0050] The HO destination prediction unit 30 predicts that the handover destination will be base station 200B from among a plurality of surrounding base stations that are HO candidates, based on information on past performance acquired from the performance value DB 20. For example, the HO destination prediction unit 30 acquires from the performance value DB 20 information on past performance of handover destinations for the current direction of arrival waves from base station 200A at terminal 100, and predicts that the handover destination will be base station 200B based on the past performance.

[0051] Next, the arrival wave direction prediction unit 40 predicts the arrival wave direction from base station 200B to terminal 100 (terminal 100 at its destination after HO) based on the arrival wave direction from base station 200A, the position of base station 200A, and the position of base station 200B.

[0052] For example, in Figure 8, assume that terminal 100 is in the area indicated by C, and the direction of the incoming wave from base station 200A to terminal 100 is as shown. Terminal 100 (arrival wave direction prediction unit 40) does not know its own exact location, but it does know the direction of the incoming wave from base station 200A, the position of base station 200A, and the position of base station 200B. Furthermore, based on information acquired from performance value DB 20, terminal 100 knows that it is in area C from the direction of the incoming wave from base station 200A and past handover performance. Therefore, terminal 100 (arrival wave prediction unit 40) can predict the direction of the incoming wave after HO, as shown in the figure.

[0053] Next, the directivity control unit 50 controls the antenna 15 so that the directivity is oriented in the direction of the incoming wave predicted by the incoming wave direction prediction unit 40 .

[0054] Example a is assumed to be applied when the accuracy of location information is poor, such as in a place with poor GPS sensitivity or indoors, or when the state of the gyro sensor of the terminal 100 is poor. Even in such cases, example a makes it possible to predict the direction of arrival waves after HO based on the relative positional relationship between the current base station and the HO-destination base station, etc.

[0055] (Incoming wave direction prediction: Example b) Next, example b of incoming wave direction prediction will be described. In example b, the incoming wave direction at each position is predicted based on information in the performance value DB 20. Furthermore, the terminal 100 corrects the incoming wave direction based on the tilt of the terminal 100. A specific example of the processing operation is as follows. Here, it is assumed that the receiver 10 is capable of receiving signals from surrounding base stations.

[0056] A receiver 10 of a terminal 100 located in the cell of the base station 200A receives signals (synchronization signals, etc.) from the base station 200A and a plurality of surrounding base stations.

[0057] The HO destination prediction unit 30 predicts that the handover destination will be the base station 200B from among a plurality of surrounding base stations that are HO candidates, based on information on past performance acquired from the performance value DB 20. For example, the HO destination prediction unit 30 acquires from the performance value DB 20 information on past performance of handover destinations for the current position of the terminal 100, and predicts that the handover destination will be the base station 200B based on the past performance.

[0058] Next, the arrival wave direction prediction unit 40 predicts the position of the terminal 100 after handover, which is moving to the handover destination, from the current position of the terminal 100 (and the direction of travel, speed, etc. of the terminal 100), and obtains the direction of the arrival wave from the base station 200B at that predicted position based on the information obtained from the actual value DB 20.

[0059] When the terminal 100 is held in the hand, it is often used at an angle. The arrival wave direction prediction unit 40 can obtain this angle (for example, the angle of the terminal 100 from the vertical position). Therefore, the arrival wave direction prediction unit 40 corrects the predicted arrival wave direction according to the angle of the terminal 100.

[0060] Finally, the directivity control unit 50 controls the antenna 15 so that the directivity is oriented in the direction of the incoming wave, which is corrected in accordance with the tilt of the terminal 100 relative to the predicted direction of the incoming wave.

[0061] Example b is intended for application in an outdoor environment with good GPS sensitivity and where the tilt of the terminal 100 can also be detected with high sensitivity. In such a case, the direction of the incoming wave can be predicted from absolute value information such as the current position and the tilt of the terminal 100.

[0062] (Hardware Configuration Example) The terminal 100 (communication device) described in this embodiment can be realized, for example, by causing a computer to execute a program. This computer may be a physical computer or a virtual machine on the cloud.

[0063] That is, the terminal 100 can be realized by using hardware resources such as a CPU and memory built into a computer to execute a program corresponding to the processing performed by the terminal 100. The program can be recorded on a computer-readable recording medium (such as a portable memory) and can be saved or distributed. The program can also be provided via a network such as the Internet or email.

[0064] Fig. 9 is a diagram showing an example of the hardware configuration of the computer. The computer in Fig. 9 includes a drive device 1000, an auxiliary storage device 1002, a memory device 1003, a CPU 1004, an interface device 1005, a display device 1006, an input device 1007, an output device 1008, and the like, all of which are interconnected via a bus B. The computer may further include a GPU.

[0065] The program that realizes the processing on the computer is provided by a recording medium 1001, such as a CD-ROM or a memory card. When the recording medium 1001 storing the program is set in the drive device 1000, the program is installed from the recording medium 1001 to the auxiliary storage device 1002 via the drive device 1000. However, the program does not necessarily have to be installed from the recording medium 1001, but may be downloaded from another computer via a network. The auxiliary storage device 1002 stores the installed program as well as necessary files, data, etc.

[0066] The memory device 1003 reads and stores a program from the auxiliary storage device 1002 when an instruction to start the program is received. The CPU 1004 realizes functions related to the terminal 100 in accordance with the program stored in the memory device 1003. The interface device 1005 is used as an interface for connecting to a network, etc. The display device 1006 displays a GUI (Graphical User Interface) or the like according to the program. The input device 1007 is composed of a keyboard, mouse, buttons, a touch panel, etc., and is used to input various operation instructions. The output device 1008 outputs the results of calculations.

[0067] (Summary, Effects, etc. of the Embodiment) As described above, the technology described in the present embodiment allows the terminal 100 to form a directional beam pattern after handover based on the direction of arrival waves from the currently connected base station and information acquired from the performance value DB 20. Therefore, it is possible to form an optimal beam pattern for communication with the handover destination base station without communicating with the handover destination base station in advance. In other words, for a terminal with high directivity, forming an optimal beam pattern immediately after handover can expand the usable range of high frequency bands.

[0068] The following additional notes are provided regarding the above-described embodiments.

[0069] <Additional Notes> (Additional Item 1) A communication device having directionality, comprising: a receiving unit that receives radio waves from a base station and stores the direction of arrival waves and location information of the communication device in a database, and a processing unit that predicts the direction of arrival waves from a handover destination base station based on past information acquired from the database, and controls the directivity of the communication device based on the prediction result. (Additional Item 2) A communication system comprising a communication device having directionality and a database, wherein the communication device comprises: a receiving unit that receives radio waves from a base station and stores the direction of arrival waves and location information of the communication device in the database, and a processing unit that predicts the direction of arrival waves from a handover destination base station based on past information acquired from the database, and controls the directivity of the communication device based on the prediction result. (Supplementary Item 3) A communication method executed by a directional communication device, comprising the steps of receiving radio waves from a base station and storing the direction of the incoming wave and location information of the communication device in a database, and predicting the direction of the incoming wave from a handover destination base station based on past information acquired from the database, and controlling the directivity of the communication device based on the prediction result. (Supplementary Item 4) A non-transitory storage medium storing a program for causing a computer to function as a directional communication device, comprising: a receiving unit that receives radio waves from a base station and stores the direction of the incoming wave and location information of the communication device in a database, and a processing unit that predicts the direction of the incoming wave from a handover destination base station based on past information acquired from the database, and controlling the directivity of the communication device based on the prediction result.

[0070] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0071] REFERENCE SIGNS LIST 10 Receiving unit 15 Antenna 20 Performance value DB 30 HO destination prediction unit 40 Arrival wave direction prediction unit 50 Directivity control unit 100 Terminal 200 Base station 300 Network 1000 Drive device 1001 Recording medium 1002 Auxiliary storage device 1003 Memory device 1004 CPU 1005 Interface device 1006 Display device 1007 Input device 1008 Output device

Claims

1. A directional communication device comprising: a receiving unit that receives radio waves from a base station and stores the direction of the incoming waves and the location information of the communication device in a database; and a processing unit that predicts the direction of the incoming waves from a base station to which the communication device is handed over based on past information obtained from the database, and controls the directivity of the communication device based on the prediction result.

2. A communication system comprising a directional communication device and a database, wherein the communication device comprises: a receiving unit that receives radio waves from a base station and stores the direction of the incoming wave and location information of the communication device in the database; and a processing unit that predicts the direction of the incoming wave from a handover destination base station of the communication device based on past information obtained from the database, and controls the directivity of the communication device based on the prediction result.

3. A communication method executed by a directional communication device, comprising the steps of: receiving radio waves from a base station, and storing the direction of the incoming wave and location information of the communication device in a database; and predicting the direction of the incoming wave from a handover destination base station of the communication device based on past information obtained from the database, and controlling the directivity of the communication device based on the prediction result.

4. A program for causing a computer to function as a directional communication device, comprising: a receiving unit that receives radio waves from a base station and stores the direction of the incoming waves and the location information of the communication device in a database; and a processing unit that predicts the direction of the incoming waves from a handover destination base station of the communication device based on past information obtained from the database, and controls the directivity of the communication device based on the prediction result.

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