Communication device

Abstract

In order to make it possible to predict deterioration of radio quality caused by a handover in a radio communication system in which a base station and a terminal perform radio communication, this communication device performs radio communication with a base station, and includes: a database that, when a handover occurs, stores information on base stations involved in the handover and information on radio quality during the handover; and a radio quality prediction unit that, when a handover is predicted, predicts and outputs a change in radio quality due to the handover on the basis of the information stored in the database.

Description

communication equipment

[0001] The present invention relates to a communication device.

[0002] In order to achieve high-quality wireless communication, various wireless communication quality prediction techniques have been researched and developed. For example, a communication control method is known in which a receiver in a wireless communication system having multiple propagation paths predicts the movement of an obstacle and controls the switching of the propagation paths (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2020-92386

[0004] In wireless communication systems where base stations and terminals communicate wirelessly, handovers (changing the base station to which the terminal communicates) occur when the terminal moves, because there is a limit to the area in which each base station can communicate. Handovers may or may not result in a deterioration in wireless quality, but conventional technologies do not predict changes in wireless quality due to handovers, and therefore the deterioration in wireless quality caused by handovers reduces the accuracy of wireless quality predictions.

[0005] The embodiments of the present invention have been made in view of the above-mentioned problems, and make it possible to predict deterioration of wireless quality due to handover in a wireless communication system in which a base station and a terminal perform wireless communication.

[0006] In order to solve the above problem, a communication device according to an embodiment of the present invention is a communication device that performs wireless communication with a base station, and includes: a database that stores information about the base station and information about wireless quality at the time of a handover when the handover occurs; and a wireless quality prediction unit that, when a handover is predicted, predicts and outputs a change in wireless quality due to the handover based on the information stored in the database.

[0007] According to an embodiment of the present invention, in a wireless communication system in which a base station and a terminal perform wireless communication, it becomes possible to predict degradation of wireless quality due to handover.

[0008] FIG. 1 is a diagram illustrating an example of a system configuration of a wireless communication system according to the present embodiment. FIG. 2 is a diagram illustrating an example of a functional configuration of a terminal according to the present embodiment. FIG. 3 is a flowchart illustrating an example of a prediction process of wireless quality according to the present embodiment. FIG. 4 is a diagram illustrating an example of information stored in a performance value DB according to the present embodiment. FIG. 5 is a diagram (1) illustrating an example of a prediction process of a handover destination according to the present embodiment. FIG. 6 is a diagram (2) illustrating an example of a prediction process of a handover destination according to the present embodiment. FIG. 7 is a diagram (1) illustrating a method for predicting a change in wireless quality according to the present embodiment. FIG. 8 is a diagram (2) illustrating a method for predicting a change in wireless quality according to the present embodiment. FIG. 9 is a diagram (3) illustrating a method for predicting a change in wireless quality according to the present embodiment. FIG. 10 is a diagram illustrating a method for predicting a change in wireless quality according to the present embodiment.

[0009] Hereinafter, an embodiment of the present invention 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.

[0010] <System Configuration> Fig. 1 is a diagram showing an example of the system configuration of a wireless communication system according to this embodiment. The wireless communication system 1 includes base stations 10a, 10b, ... and terminals 20 that perform wireless communication with the base stations 10a, 10b, .... The wireless communication system 1 includes, but is not limited to, wireless communication systems such as LTE (Long Term Evolution) and / or 5G (5th Generation). In the following description, the term "base station 10" will be used to refer to any base station among the base stations 10a, 10b, .... The number of base stations 10 shown in Fig. 1 is merely an example, and may be two or more.

[0011] (Problem) In a wireless communication system 1 in which base stations and terminals communicate wirelessly, there is a limit to the area in which each base station 10 can communicate, and therefore, movement of the terminal 20 causes handover (changing the base station with which it communicates). For example, in FIG. 1, assume that the terminal 20 moves from a wireless area 11a in which it can communicate wirelessly with the base station 10a to a wireless area 11b in which it can communicate wirelessly with the base station 10b. In this case, the movement of the terminal 20 causes handover from the base station 10a to the base station 10b, and at this time, there is a possibility that wireless quality will deteriorate. However, with conventional technology, it is difficult to predict deterioration of wireless quality due to handover.

[0012] Therefore, in this embodiment, in a wireless communication system 1 in which a base station and a terminal perform wireless communication, in order to be able to predict deterioration of wireless quality due to handover, the terminal 20 has a functional configuration such as that shown in FIG. 2, for example.

[0013] <Functional Configuration> Fig. 2 is a diagram showing an example of the functional configuration of a terminal according to this embodiment. As shown in Fig. 2, terminal (communication device) 20 has an antenna 201, a communication unit 202, a performance value DB (Database) 203, a handover prediction unit 204, a wireless quality prediction unit 205, etc. Terminal 20 has a computer configuration, and for example, the communication unit 202, the performance value DB (Database) 203, the handover prediction unit 204, the wireless quality prediction unit 205, etc. are realized by a program executed by the computer, etc.

[0014] The terminal 20 is an example of a communication device according to the present embodiment, and is assumed to be, for example, a user terminal (UE: User Equipment) of a mobile communication system such as LTE and / or 5G. However, the communication device according to the present embodiment is not limited to this, and may be various devices having a communication function for wirelessly communicating with the base station 10. For example, the communication device according to the present embodiment may be the terminal 20, or a device equipped with the functions of the terminal 20, such as a vehicle, a senior car, a robot, or a drone.

[0015] The communication unit 202 executes communication processing to perform wireless communication with the base station 10 via the antenna 201. For example, the communication unit 202 executes reception processing to receive radio waves from the base station 10. The communication unit 202 also executes transmission processing to transmit, to the base station 10, for example, the reception results of radio waves from the base station 10 or the prediction results by the wireless quality prediction unit 205. Furthermore, the communication unit 202 executes communication control processing to control the communication processing.

[0016] The actual value DB 203 is a database that stores information about the base station and wireless quality information in a handover when a handover occurs in the communication unit 202. Here, the base station information includes, for example, identification information such as a PCI (Physical Cell ID) or a CID (Cell-ID) of the handover destination base station 10. Alternatively, the base station information includes identification information of the handover source base station 10 and identification information of the handover destination base station 10. Furthermore, the wireless quality information includes, for example, a change in wireless quality such as throughput, or a wireless quality value. Note that the actual value DB 23 is an example of a database according to this embodiment.

[0017] The handover prediction unit 204 executes handover prediction processing to predict the base station 10 to which the terminal (communication device) 20 will be handed over, based on the radio parameters of the base station 10 and / or the location of the terminal (communication device) 20. An example of specific processing content of the handover prediction unit 204 will be described later.

[0018] When a handover of the terminal (communication device) 20 is predicted, the wireless quality prediction unit 205 executes a wireless quality prediction process to predict and output a change in wireless quality due to the handover based on the information stored in the actual value DB 203. For example, the wireless quality prediction unit 205 predicts the amount of change in wireless quality, the value of wireless quality, or whether or not the wireless quality will deteriorate when the terminal 20 hands over to the handover destination base station.

[0019] Preferably, the wireless quality predicting unit 205 predicts a change in wireless quality based on the worst value, average value, percentile, or the like of the wireless quality information stored in the performance value DB 203 .

[0020] The wireless quality prediction unit 205 also outputs the prediction result to a predetermined output destination. For example, the wireless quality prediction unit 205 transmits (outputs) the prediction result to the base station 10 or the like with which the wireless quality prediction unit 205 is currently communicating via the communication unit 202.

[0021] 2 is an example. For example, the terminal 20 may include an information management unit that stores and manages information about the base station and wireless quality in the actual value DB 203 when a handover occurs in the communication unit 202. The terminal 20 may also include an output unit that outputs (transmits) the prediction result by the wireless quality prediction unit 205.

[0022] <Processing Flow> Next, the processing flow of the wireless quality prediction method according to this embodiment will be described.

[0023] 3 is a flowchart showing an example of a wireless quality prediction process according to the present embodiment, which is executed by, for example, a terminal (communication device) 20 having the functional configurations described in FIG.

[0024] In step S301, the communication unit 202 of the terminal 20 receives wireless information via the antenna 201.

[0025] In step S302, the terminal 20 determines whether or not a handover has occurred immediately after the reception of the wireless information. If the handover has occurred immediately after the reception of the wireless information, the terminal 20 proceeds to step S303. On the other hand, if the handover has not occurred immediately after the reception of the wireless information, the terminal 20 proceeds to step S304.

[0026] When the process proceeds to step S303, the terminal 20 stores the information on the base station 10 and the information on the wireless quality in the performance value DB 203. Note that, in this embodiment, the following two methods are assumed for storing the information in the performance value DB 203.

[0027] The first method is a method in which, when a handover occurs, information about the base station 10 at the handover destination (e.g., PCI or CID, etc.) and information about wireless quality (e.g., the amount of change in wireless quality or the value of wireless quality) are stored in the actual value DB 203. For example, in FIG. 4, when the terminal 20 performs a handover from one of base stations a to d to base station X, the terminal 20 stores information about the base station X at the handover destination and information about wireless quality in the actual value DB 203. This method is suitable when degradation in wireless quality is caused by a specific base station or by the surrounding environment.

[0028] The second method is a method in which, when a handover occurs, information on the handover source base station 10, information on the handover destination base station 10, and information on wireless quality are stored in the performance value DB 203. For example, in Fig. 4, when the terminal 20 performs a handover from base station a to base station X, the terminal 20 stores information on the handover source base station a, information on the handover destination base station X, and information on wireless quality in the performance value DB 203. This method is suitable, for example, when the wireless quality is significantly degraded due to a handover from a base station 10 with good wireless quality to a base station 10 with poor wireless quality.

[0029] Preferably, in either the first method or the second method, the terminal 20 stores radio parameter information at the time of handover occurrence in the actual value DB 203. This radio parameter information includes, for example, the RSRP (Reference Signal Received Power) of the base station 10 currently in communication, and the RSRP of the adjacent base station 10 adjacent to the base station 10 currently in communication.

[0030] When the process proceeds to step S304, the handover prediction unit 204 of the terminal 20 predicts the handover destination (handover destination base station 10) of the terminal 20. In this embodiment, the following three methods are assumed as methods for predicting the handover destination.

[0031] The first method is a method of predicting a handover destination from radio parameters (such as RSRP) of a base station 10 currently in communication (hereinafter referred to as the communicating base station) and a base station 10 adjacent to the communicating base station (hereinafter referred to as the adjacent base station). For example, if the RSRP from the adjacent base station is greater than the RSRP from the communicating base station, the handover prediction unit 204 predicts that the terminal 20 will hand over to the adjacent base station. For example, as shown in FIG. 5, assume that the RSRP of the communicating base station, the RSRP of adjacent base station A, and the RSRP of adjacent base station B have changed at times t and t+1. In this case, the handover prediction unit 204 predicts that the terminal 20 will hand over from the communicating base station to adjacent base station B.

[0032] The second method predicts the handover destination from the past handover locations of the terminal 20. Here, it is assumed that the relationship between the location of the terminal 20 and the handover destination base station 10 is reproducible. In the second method, when a handover occurs, the terminal 20 stores, in the performance value DB 203, location information indicating the location of the terminal 20 in addition to information on the base station 10 and information on wireless quality. For example, as shown in FIG. 6 , it is assumed that the terminal 20, which was previously communicating with the base station 10a, handed over to the base station 10b at point A. In this case, the handover prediction unit 204 predicts that the terminal 20 will hand over from the base station 10a to the base station 10b if the location of the terminal 20 moves to point A while communicating with the base station 10a.

[0033] The third method is a method of predicting the handover destination based on the past handover positions of the terminal 20, information on the radio parameters of the communicating base station and adjacent base stations, and location information of the terminal 20. Here, it is assumed that the handover destination is predicted by machine learning or the like. For example, the handover prediction unit 204 predicts the handover destination base station 10 using a machine learning model that has been trained in advance to predict the handover destination base station 10 from the current location information of the terminal 20 and the radio parameters of the base station 10.

[0034] In step S305, the handover prediction unit 204 determines whether a handover is predicted in the process of step S04. If a handover is predicted, the handover prediction unit 204 proceeds to step S306. On the other hand, if a handover is not predicted, the handover prediction unit 204 ends the process of FIG. 3.

[0035] In step S306, the wireless quality prediction unit 205 of the terminal 20 predicts a change in wireless quality due to handover based on the information stored in the performance value DB 203. In this embodiment, the following three methods are assumed as methods for predicting a change in wireless quality.

[0036] The first method is a method of predicting a change in wireless quality from the worst value in the performance value DB 203. This method assumes the use of an application (hereinafter referred to as an app) that requires stable communication.

[0037] For example, the wireless quality prediction unit 205 creates a graph 700 showing the CDF (cumulative distribution function) ratio of the amount of change in throughput, as shown in Fig. 7, from the information stored in the actual value DB 203, and sets the minimum value (worst value) as the predicted value of the amount of change in throughput due to handover. Alternatively, the wireless quality prediction unit 205 creates a graph 800 showing the number of actual throughputs immediately after handover, as shown in Fig. 8, from the information stored in the actual value DB 203, and sets the minimum value (worst value) as the predicted value of the throughput immediately after handover. Note that throughput is an example of wireless quality. Furthermore, it is not essential for the wireless quality prediction unit 205 to create a graph such as the graph 700 or the graph 800, and the worst value may be obtained without using a graph.

[0038] The second method is a method of predicting changes in wireless quality from the average value of the performance value DB 203. This method assumes the use of a normal application.

[0039] For example, the wireless quality prediction unit 205 creates a graph 700 showing the rate of CDF (cumulative distribution function) of the amount of change in throughput as shown in Fig. 7 from the information stored in the actual value DB 203, and uses the average value instead of the minimum value as the predicted value of the amount of change in throughput due to handover. Alternatively, the wireless quality prediction unit 205 creates a graph 800 showing the number of actual cases of throughput immediately after handover as shown in Fig. 8 from the information stored in the actual value DB 203, and uses the average value instead of the minimum value as the predicted value of the throughput immediately after handover. Note that it is not essential for the wireless quality prediction unit 205 to create a graph such as graph 700 or graph 800, and the average value may be calculated without using a graph.

[0040] The third method is a method of predicting changes in wireless quality from quantiles (percentile values) of the performance value DB 203. This method assumes the use of normal applications.

[0041] For example, the wireless quality predicting unit 205 creates a graph 900 showing the percentage of the CDF (cumulative distribution function) of the amount of change in throughput, as shown in FIG. 9 , from the information stored in the actual value DB 203. The wireless quality predicting unit 205 also sets, for example, the amount of change in throughput when the percentile value is 20%, as the predicted value of the amount of change in throughput due to handover. Alternatively, the wireless quality predicting unit 205 creates a graph 1010 showing the number of actual cases of throughput immediately after handover, as shown in FIG. 10 , from the information stored in the actual value DB 203. The wireless quality predicting unit 205 also sets, for example, the 20th percentile value of the throughput immediately after handover as the predicted value of the throughput immediately after handover. It is not essential for the wireless quality predicting unit 205 to create a graph such as graph 700 or graph 800; percentile values, etc., may be calculated without using a graph.

[0042] The first to third wireless quality prediction methods may be selected by an application executed by the terminal 20, or may be set by a user who uses the terminal 20. Alternatively, the terminal 20 may be one that implements any one of the first to third wireless quality prediction methods.

[0043] 3 , the description of the flowchart will be continued. In step S307, the wireless quality prediction unit 205 outputs the prediction result. For example, the wireless quality prediction unit 205 outputs the prediction result to the communication unit 202, and the communication unit 202 transmits the prediction result to the base station 10.

[0044] According to this embodiment, by repeatedly executing the process of FIG. 3, it is possible to predict deterioration of wireless quality due to handover in the wireless communication system 1 in which the base station 10 and the terminal 20 perform wireless communication.

[0045] <Hardware Configuration> The terminal (communication device) 20, the base station 10, and the like according to this embodiment can all be realized by executing a program on a computer.

[0046] That is, the terminal 20, the communication device, the base station 10, etc. can be realized by executing a program corresponding to the processing performed by the device using hardware resources such as a CPU and memory built into a computer. The program can be recorded on a computer-readable recording medium (such as a portable memory) and stored or distributed. The program can also be provided via a network such as the Internet or email.

[0047] Fig. 11 is a diagram showing an example of the hardware configuration of a computer. In the example of Fig. 11, a computer 1100 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, which are all interconnected by a bus BS.

[0048] A program for realizing processing on the computer 1100 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.

[0049] 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 device 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.

[0050] The CPU 1004 may be a processor such as a DSP (Digital Signal Processor), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0051] (Supplementary Note) The terminal (communication device) 20, the base station 10, and the like in this embodiment may be realized not only by dedicated devices but also by general-purpose computers. In this case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed to realize the function. Note that the term "computer system" here includes hardware such as an OS and peripheral devices.

[0052] Furthermore, "computer-readable recording medium" includes various storage devices such as portable media such as flexible disks, optical magnetic disks, ROMs, CD-ROMs, and storage devices built into computer systems. Furthermore, "computer-readable recording medium" may also include devices that dynamically store a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and devices that store a program for a certain period of time, such as volatile memory within a computer system that serves as a server or client in such cases.

[0053] Furthermore, the above program may be one that realizes part of the above-mentioned functions, or may be one that can realize the above-mentioned functions in combination with a program already recorded in a computer system, or may be one that is realized using hardware such as a PLD or FPGA.

[0054] <Effects of the Embodiment> According to the present embodiment, in a wireless communication system in which a base station and a terminal perform wireless communication, it becomes possible to predict degradation of wireless quality due to handover.

[0055] Furthermore, it becomes possible to predict which handovers will result in degradation of wireless quality and which will not, based on the base station 10 at the handover destination, thereby improving the accuracy of prediction of wireless quality.

[0056] Summary of Embodiments This specification discloses at least the communication device, prediction method, program, etc. described in the following paragraphs. (Item 1) A communication device that performs wireless communication with a base station, comprising: a database that stores, when a handover occurs, information about the base station and information about wireless quality at the time of the handover; and a wireless quality prediction unit that, when a handover is predicted, predicts and outputs a change in wireless quality due to the handover based on the information stored in the database. (Item 2) The communication device described in paragraph 1, further comprising: a handover prediction unit that predicts a base station as a handover destination based on wireless parameters of the base station and / or a location of the communication device, wherein the wireless quality prediction unit predicts the amount of change in wireless quality, the value of the wireless quality, or whether the wireless quality will deteriorate when the communication device hands over to the base station as a handover destination. (Item 3) The communication device described in paragraph 1 or 2, wherein the wireless quality prediction unit predicts the change in wireless quality based on a worst value, an average value, or a quantile of the wireless quality information stored in the database. (Clause 4) The communication device according to any one of clauses 1 to 4, wherein the information about the base station includes identification information of a base station to which the handover is to be made when the handover occurs, or identification information of a base station from which the handover occurred and identification information of a base station to which the handover is to be made when the handover occurred, and the information about wireless quality includes an amount of change in the wireless quality or a value of the wireless quality. (Clause 5) A prediction method, wherein a communication device that performs wireless communication with a base station stores, in a database, information about the base station and information about the wireless quality at the time of the handover when a handover occurs, predicts a change in wireless quality due to the handover based on the information stored in the database when a handover is predicted, and outputs the prediction result. (Clause 6) A program that causes a computer to execute the prediction method according to clause 5.

[0057] 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.

[0058] REFERENCE SIGNS LIST 1 Wireless communication system 10, 10a, 10b Base station 20 Terminal (an example of a communication device) 202 Communication unit 203 Performance value DB (database) 204 Handover prediction unit 205 Wireless quality prediction unit 1100 Computer

Claims

1. A communication device that performs wireless communication with a base station, comprising: a database that stores information about the base station and wireless quality at the time of a handover when the handover occurs; and a wireless quality prediction unit that, when a handover is predicted, predicts and outputs a change in wireless quality due to the handover based on the information stored in the database.

2. A communication device as described in claim 1, comprising a handover prediction unit that predicts a base station to which the communication device will hand over based on the radio parameters of the base station and / or the location of the communication device, wherein the radio quality prediction unit predicts the amount of change in the radio quality, the value of the radio quality, or whether the radio quality will deteriorate when the communication device hands over to the base station to which the communication device will hand over.

3. The communication device according to claim 1, wherein the wireless quality prediction unit predicts a change in the wireless quality based on a worst value, an average value, or a quantile of the wireless quality information stored in the database.

4. The communication device of claim 1, wherein the information about the base station includes identification information of the base station to which the handover is directed when the handover occurs, or identification information of the base station from which the handover is directed and identification information of the base station to which the handover is directed when the handover occurs, and the information about the wireless quality includes the amount of change in the wireless quality or the value of the wireless quality.

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