Communication device, communication method, and program

Abstract

The present disclosure relates to a communication device that performs radio communication with a base station, the communication device comprising: a communication unit that transmits, to a specific server, actual measured values including identification information of a base station with which the communication device is communicating and radio quality information indicating the radio quality during communication; a handover destination predicting unit that predicts a specific base station as a handover destination on the basis of the actual measured values for the radio communication with the base station with which the communication device is communicating and the actual measured values for a handover destination candidate acquired from the specific server; a radio quality predicting unit that, on the basis of the measured values for a given communication device in the specific base station of the handover destination, acquired from the specific server, and the actual measured values for the communication device in the base station with which the communication device is communicating, predicts a change in radio quality due to the handover, and thereby outputs a predicted value relating to radio quality; and a predicted value correcting unit that corrects the predicted value by using specific actual measured values based on the actual measured values for the given communication device in the specific base station.

Description

Communication device, communication method, and program

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

[0002] In wireless communication systems for terminals (communication devices) such as LTE and 5G, there is a limit to the area in which each base station can communicate, so when a terminal moves, the base station it communicates with changes (handover). In this case, the handover destination is determined based on the results of a comparison of wireless quality, such as throughput, between the base station currently communicating with and the base station of the handover destination (Non-Patent Document 1).

[0003] 3GPP TS 36.300 V18.0.0 (2023-12)

[0004] However, if the communication conditions at the destination base station are tight, there is a possibility that the wireless quality after the handover will deteriorate. Therefore, even if the wireless quality after the handover is predicted, the accuracy of the prediction of the wireless quality will be low.

[0005] The present disclosure has been made in view of the above-mentioned problems, and aims to suppress a decrease in the accuracy of predicting wireless quality when predicting wireless quality at a handover destination.

[0006] In order to solve the above-mentioned problems, the present disclosure provides a communication device that performs wireless communication with a base station, the communication device having: a communication unit that transmits actual measurement values ​​including identification information of a base station with which the communication device is communicating and wireless quality information indicating wireless quality during communication to a predetermined server; a handover destination prediction unit that predicts a predetermined base station as a handover destination based on the actual measurement values ​​in wireless communication with the base station with which the communication device is communicating and the actual measurement values ​​of candidate handover destinations acquired from the predetermined server; a wireless quality prediction unit that predicts a change in wireless quality due to handover based on the actual measurement values ​​of an arbitrary communication device at the predetermined base station with which the communication device is communicating acquired from the predetermined server and the actual measurement values ​​of the communication device at the base station with which the communication device is communicating, and thereby outputs a predicted value regarding wireless quality; and a predicted value correction unit that corrects the predicted value using the predetermined actual measurement values ​​based on the actual measurement values ​​of the arbitrary communication device at the predetermined base station.

[0007] According to the embodiment of the present invention, when predicting the wireless quality of a handover destination, it is possible to suppress a decrease in the prediction accuracy of the wireless quality.

[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 a prediction process of a handover destination according to the present embodiment. FIG. 5 is a diagram illustrating an example of a prediction process of a handover destination according to the present embodiment. FIG. 6 is a diagram illustrating an example of a prediction process of a change in wireless quality according to the present embodiment. FIG. 7 is a diagram illustrating an example of a prediction process of a change in wireless quality according to the present embodiment. FIG. 8 is a diagram illustrating an example of a prediction process of 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. Note that the present invention is not limited to the embodiment shown below, and various modifications are possible within the scope of the technical concept of the present invention.

[0010] <System Configuration> FIG. 1 is a diagram illustrating 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, ..., a terminal 20 that performs wireless communication with any of the base stations 10a, 10b, ..., and a server 40 (described later). 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 illustrated in FIG. 1 is merely an example, and may be two or more.

[0011] [Functional Configuration] FIG. 2 is a diagram showing an example of the functional configuration of the terminal and server according to this embodiment.

[0012] 2, the server 40 has a communication unit 41. The server 40 has a computer configuration, and the communication unit 21 is realized by a program executed on the computer.

[0013] The communication unit 41 communicates data with the communication unit 21 of the terminal 20, thereby receiving actual measurement values ​​transmitted from the communication unit 21 of the terminal 20 and storing them in the actual measurement value DB 49, or reading actual measurement values ​​from the actual measurement value DB 49 and transmitting them to the communication unit 21 of the terminal 20.

[0014] The server 40 also has an actual measurement value DB (Data Base) 49 built in a storage unit such as a memory 1002 or an auxiliary storage device 1003 (described later). The actual measurement value DB 49 stores, for each base station, actual measurement values ​​received by the communication unit 41 from the terminal 20. These actual measurement values ​​include identification information of the base station 10 with which a given source terminal is communicating, wireless quality information, location information of the terminal 20, and the time (time) at which these pieces of information were transmitted. The wireless quality includes throughput, RB (Resource Block), RSRP (Reference Signal Received Power), etc. The actual measurement values ​​may also include communication traffic volume.

[0015] The actual measurement value DB 49 may store the actual measurement values ​​sent from each terminal 20 as they are, or the communication unit 41 may manage wireless quality information, which is a value calculated by each terminal 20 as a time average or a time median, in the actual measurement value DB 49. This makes it possible to process outliers, instantaneous fluctuations, etc., summarize time fluctuations, and then reduce the amount of data for management. The communication unit 41 may also manage wireless quality information, which is a value calculated by each terminal 20 as a spatial (position) average or a spatial median, in the actual measurement value DB 49. This makes it possible to process outliers, instantaneous fluctuations, etc., summarize movement fluctuations, and then reduce the amount of data for management. The communication unit 41 may calculate the time average or the time median and the spatial (position) average or the spatial median in a combined manner.

[0016] 2 , the terminal (an example of a communication device) 20 has an antenna 21 a, a communication unit 21, a handover destination prediction unit 22, a wireless quality prediction unit 23, an actual measurement value use determination unit 24, and a prediction value correction unit 25. The terminal 20 has a computer configuration, and the communication unit 21, the handover destination prediction unit 22, the wireless quality prediction unit 23, the actual measurement value use determination unit 24, and the prediction value correction unit 25 are realized by programs executed on the computer, etc. The handover destination prediction unit 22, the wireless quality prediction unit 23, and the actual measurement value use determination unit 24 communicate with the server 40 via the communication unit 21.

[0017] 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 (Long Term Evolution) 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 mobility scooter, a robot, or a drone.

[0018] (Communication Unit) The communication unit 21 performs wireless communication with the base station 10 via the antenna 21 a, acquires identification information of the base station 10 with which the communication is currently being performed from the base station 10, and measures the wireless quality of the current wireless communication. Note that the wireless quality may be measured by the base station 10 and transmitted to the terminal 20 as wireless quality information indicating the wireless quality.

[0019] For example, the communication unit 21 acquires current location information of the terminal 20 from a GPS device 1005 (described later) provided in the terminal 20. The communication unit 21 also outputs an actual measurement value of the communication status of radio waves from the base station 10 to the wireless quality prediction unit 23 and transmits it to the base station 10.

[0020] (Handover Destination Prediction Unit) The handover destination prediction unit 22 acquires actual measurement values ​​of the current terminal 20 from the communication unit 21. Based on the identification information of the base station 10 in the actual measurement values ​​of the current terminal 20, the handover destination prediction unit 22 acquires actual measurement values ​​of each terminal at base stations that are neighboring (adjacent) base stations around the base station 10 and are candidate handover destinations from the server 40 via the communication unit 21. Then, based on the actual measurement values ​​of the current terminal 20 and the actual measurement values ​​of each terminal at the candidate handover destination base stations, the handover destination prediction unit 22 predicts the base station 10 to which the terminal 20 will be handovered, and outputs identification information of the predicted handover destination base station to the wireless quality prediction unit 23. Note that an example of specific processing content of the handover destination prediction unit 22 will be described later.

[0021] (Wireless Quality Prediction Unit) The wireless quality prediction unit 23 acquires, from the server 40, actual measurement values ​​of each terminal at the base station 10 corresponding to the identification information of the handover destination base station 10, based on the identification information of the handover destination base station 10 acquired from the handover destination prediction unit 22. Then, the wireless quality prediction unit 23 predicts a change in wireless quality due to handover, based on the actual measurement values ​​of the terminal 20 acquired from the communication unit 21 and the actual measurement values ​​acquired from the server 40. For example, the wireless quality prediction unit 23 predicts the amount of change in wireless quality, the value of wireless quality, whether or not wireless quality will deteriorate, etc., when the terminal 20 hands over to the handover destination base station.

[0022] Preferably, the wireless quality predicting unit 23 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 actual measurement value DB 49 .

[0023] In addition, the wireless quality prediction unit 23 may obtain only the actual measurement values ​​for a specific terminal 20 that is located closest to the terminal 20 at the handover destination from the server 40 based on the location information of the terminal 20 in the actual measurement values ​​of the terminal 20 from the communication unit 21, and predict the change in wireless quality due to the handover.

[0024] Furthermore, the wireless quality predicting unit 23 outputs a predicted value, which is the result of the prediction, to the predicted value correcting unit 25 .

[0025] (Actual measurement value utilization determination unit) The actual measurement value utilization determination unit 24 acquires identification information of the handover destination base station from the handover destination prediction unit 22, and acquires actual measurement values ​​of each terminal 20 at the handover destination corresponding to the identification information of the handover destination base station from the communication unit 41 of the server 40 via the communication unit 21. Then, the actual measurement value utilization determination unit 24 calculates a predetermined actual measurement value av, which is the average or median of wireless quality information such as throughput for each actual measurement value. Note that, similar to the wireless quality prediction unit 23, the actual measurement value utilization determination unit 24 may acquire only actual measurement values ​​for a specific terminal 20 located closest to the terminal 20 at the handover destination from the server 40 based on location information of the terminal 20 in the actual measurement values ​​of the terminal 20 from the communication unit 21, and use this as the predetermined actual measurement value av.

[0026] Then, the actual measurement value utilization determination unit 24 determines whether the predetermined actual measurement value av is equal to or less than the threshold value th1 or equal to or greater than the threshold value th2, thereby determining whether to use the predetermined actual measurement value av to correct the predicted value predicted by the wireless quality prediction unit 23. Note that an example of specific processing contents of the actual measurement value utilization determination unit 24 will be described later.

[0027] (Predicted Value Correction Unit) The predicted value correction unit 25 acquires a predicted value from the wireless quality prediction unit 23, and also acquires a predetermined actual measurement value av of the handover destination from the actual measurement value utilization determination unit 24. Note that if the actual measurement value utilization determination unit 24 determines that the predetermined actual measurement value av will not be used, the predicted value correction unit 25 does not acquire the actual measurement value of the handover destination from the actual measurement value utilization determination unit 24.

[0028] Furthermore, the predicted value corrector 25 calculates the average value of the predicted value and the actual measured value at the handover destination to obtain a corrected predicted value.

[0029] [Processing of the embodiment] Next, the flow of processing of the wireless quality prediction method according to the present embodiment will be described.

[0030] 3 is a flowchart showing an example of a wireless quality prediction process according to the present embodiment, which is executed by the terminal 20 having the functional configurations described in FIG.

[0031] S11: The communication unit 21 of the terminal 20 receives wireless information (such as identification information of the base station 10 with which it is communicating) from the base station 10 with which it is communicating via the antenna 21a.

[0032] S12: The communication unit 21 of the terminal 20 determines whether or not it is immediately after a handover based on the received wireless information. If it is immediately after a handover (YES), the terminal 20 proceeds to process S13. On the other hand, if it is not immediately after a handover (NO), the terminal 20 proceeds to process S14. Note that "immediately after a handover" indicates, for example, within a predetermined time (e.g., 1 second) after the handover.

[0033] S13: The terminal 20 transmits the current actual measurement value of the terminal 20 to the server 40. As a result, the communication unit 41 of the server 40 receives the actual measurement value and stores the actual measurement value in the actual measurement value DB 49. Note that the following two methods are assumed for storing information in the actual measurement value DB 49 in this embodiment.

[0034] The first method is a method in which, when a handover occurs, identification information (e.g., PCI (Physical Cell Identifier) ​​or CID (Cell ID)) and wireless quality information (e.g., the amount of change in wireless quality or the value of wireless quality) of the base station 10 at the handover destination are stored in the actual measurement value DB 49. 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 communication unit 41 stores the identification information of the base station X at the handover destination, the wireless quality information, the location information of the terminal 20, and the transmission time in the actual measurement value DB 49. This method is suitable when the deterioration of wireless quality is caused by a specific base station or by the surrounding environment.

[0035] In the second method, when a handover occurs, the communication unit 41 stores the identification information of the handover source base station 10, the identification information of the handover destination base station 10, the wireless quality information, the location information of the terminal 20, and the transmission time in the actual measurement value DB 49. For example, in Fig. 4, when the terminal 20 performs a handover from base station a to base station X, the terminal 20 stores the identification information of the handover source base station a, the identification information of the handover destination base station X, the wireless quality information, the location information of the terminal 20, and the transmission time in the actual measurement value DB 49. 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.

[0036] S14: The handover destination prediction unit 22 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.

[0037] <First Method> The first method predicts a handover destination based on wireless quality information (e.g., RSRP) of the base station 10 currently communicating with the terminal 20 (hereinafter referred to as the communicating base station) related to the actual measurement value of the terminal 20 itself and the base station 10 adjacent to the communicating base station (hereinafter referred to as the adjacent base station) related to the actual measurement value of the handover destination candidate. For example, if the RSRP from the adjacent base station is greater than the RSRP from the communicating base station, the handover destination prediction unit 22 predicts that the terminal 20 will handover to the adjacent base station. For example, as shown in FIG. 5 , assume that the RSRP of the communicating base station and the RSRPs of adjacent base stations A and B, which are candidate handover destinations, change at times t and t+1. In this case, the handover destination prediction unit 22 predicts that the terminal 20 will handover from the communicating base station to adjacent base station B.

[0038] <Second Method> The second method is a method of predicting a handover destination from past handover positions of the terminal 20. Here, it is assumed that there is reproducibility in the relationship between the position of the terminal 20 and the handover destination base station 10. Note that in the second method, the terminal 20 uses actual measurement values ​​from various past handovers of the terminal 20. However, when using only the past actual measurement values ​​of the terminal 20 itself, in order to identify the actual measurement value of the terminal 20 itself from the actual measurement values ​​stored in the actual measurement value DB 49, the above-mentioned actual measurement values ​​may be stored in the actual measurement value DB 49 together with identification information of the terminal 20.

[0039] 6, assume that terminal 20, which was previously communicating with base station 10a, was handed over to base station 10b at point Y. In this case, if the location of terminal 20 moves to point Y while communicating with base station 10a, handover destination prediction unit 22 predicts that terminal 20 will be handed over from base station 10a to base station 10b.

[0040] <Third Method> The third method is a method of predicting a handover destination based on the past handover positions of the terminal 20, wireless quality information 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 destination prediction unit 22 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 wireless quality information of the base station 10.

[0041] S15: Subsequently, the handover destination prediction unit 22 determines whether or not a handover is predicted in process S14. If a handover is predicted, the handover destination prediction unit 22 proceeds to process S16. On the other hand, if a handover is not predicted, the handover destination prediction unit 22 ends the process of FIG. 3.

[0042] S16: The wireless quality prediction unit 23 of the terminal 20 identifies the predetermined handover destination base station by acquiring identification information of the predicted predetermined handover destination base station from the handover destination prediction unit 22. Furthermore, the wireless quality prediction unit 23 acquires actual measurement values ​​of each terminal communicating with the predetermined handover destination base station from the server 40, and also acquires the actual measurement value of the terminal 20 itself from the communication unit 21. Then, the wireless quality prediction unit 23 predicts a change in wireless quality due to handover based on the acquired actual measurement values ​​of the terminal 20 itself and the actual measurement values ​​of each terminal at the handover destination, and outputs the predicted value, which is the prediction result, to the predicted value correction unit 25. In this embodiment, the following three methods are assumed as methods for predicting a change in wireless quality.

[0043] <First Method> The first method is a method of predicting a change in wireless quality from the worst value in the actual measurement value DB 49. This method assumes the use of an application (hereinafter referred to as an app) that requires stable communication.

[0044] For example, the wireless quality prediction unit 23 creates a graph showing the CFD (cumulative distribution function) ratio of the amount of change in throughput as shown in Figure 7 from the actual measurement values ​​of the terminal 20 itself and the actual measurement values ​​of each terminal 20 at the handover destination, and sets the minimum value (worst value) as the predicted value of the amount of change in throughput due to handover.

[0045] Alternatively, the wireless quality prediction unit 23 creates a graph of the number of actual measurements of throughput immediately after handover, as shown in Figure 8, from the actual measurements of the terminal 20 itself and each terminal 20 at the handover destination, and sets the minimum value (worst value) as the predicted value of throughput immediately after handover.

[0046] It is not essential that the wireless quality predicting unit 23 create the graph shown in FIG. 7 or FIG. 8, and the worst value may be found without using the graph.

[0047] <Second Method> The second method is a method of predicting a change in wireless quality from an average value of wireless quality information of actual measured values ​​of the own terminal 20 and actual measured values ​​of each handover destination terminal 20. This method assumes the use of a normal application.

[0048] For example, the wireless quality prediction unit 23 creates a graph showing the proportion of the CDF (cumulative distribution function) of the amount of change in throughput, as shown in FIG. 7, from wireless quality information of the actual measured values ​​of the terminal 20 itself and the actual measured values ​​of each terminal 20 at the handover destination, and uses the average value instead of the minimum value as the predicted value of the amount of change in throughput due to handover.

[0049] Alternatively, the wireless quality prediction unit 23 creates a graph of the number of actual measurements of throughput immediately after handover, as shown in Figure 8, from wireless quality information of the actual measurement values ​​of the own terminal 20 and the actual measurement values ​​of each terminal 20 at the handover destination, and uses the average value instead of the minimum value as the predicted value of throughput immediately after handover.

[0050] It is not essential that the wireless quality predicting unit 23 create the graph shown in FIG. 7 or FIG. 8, and the average value may be calculated without using the graph.

[0051] <Third Method> The third method is a method of predicting a change in wireless quality from quantiles (percentile values) of wireless quality information in actual measurement values ​​of the own terminal 20 and actual measurement values ​​of each handover destination terminal 20. This method assumes the use of a normal application.

[0052] For example, the wireless quality prediction unit 23 creates a graph 900 showing the ratio of CDF (Cumulative Distribution Function) of the amount of change in throughput as shown in Fig. 9 from wireless quality information of the actual measurement values ​​of the terminal 20 itself and the actual measurement values ​​of each terminal 20 at the handover destination. Furthermore, the wireless quality prediction unit 23 sets the amount of change in throughput when the percentile value is 20%, for example, as the predicted value of the amount of change in throughput due to handover.

[0053] Alternatively, the wireless quality predicting unit 23 creates a graph of the number of actual measurements of throughput immediately after handover, as shown in Fig. 10, from wireless quality information of the actual measurement values ​​of the terminal 20 itself and the terminals 20 at the handover destination. Also, the wireless quality predicting unit 23 sets, for example, the 20th percentile value of the throughput immediately after handover as the predicted value of the throughput immediately after handover. Note that it is not essential for the wireless quality predicting unit 23 to create the graph shown in Fig. 9 or 10, and percentile values, etc. may be obtained without using a graph.

[0054] 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.

[0055] Next, returning to FIG. 3, the explanation of the flowchart will be continued.

[0056] S17: The wireless quality predictor 23 outputs the predicted value as the prediction result to the predicted value corrector 25.

[0057] Next, the rest of the processing of this embodiment will be described with reference to FIGS.

[0058] S31: Based on the identification information of the base station of the handover destination obtained from the handover destination prediction unit 22, the actual measurement value utilization judgment unit 24 obtains from the communication unit 41 of the server 40 a predetermined actual measurement value av of the handover destination corresponding to the identification information of the base station of the handover destination in the actual measurement value DB 49.

[0059] S32: The actual measurement value utilization determination unit 24 determines whether the predetermined actual measurement value av is equal to or less than a threshold value th1 or equal to or greater than a threshold value th2. Note that the threshold value th1 is an example of a first threshold value, and the threshold value th2 is a value greater than the threshold value th1 and is an example of a second threshold value.

[0060] For example, the actual measurement value utilization judgment unit 24 creates a graph showing the CFD (cumulative distribution function) ratio of the amount of change in throughput, as shown in Figure 13, similar to Figure 7, from a predetermined actual measurement value av of each terminal 20 at the handover destination, and judges whether the throughput of the predetermined actual measurement value av is below threshold th1 or above threshold th2.

[0061] An example of a value below the threshold th1 is when a large number of people gather at an event or the like, causing the communication quality of the handover destination terminal 20 to become extremely poor, resulting in a deviation between the predicted value and a predetermined actual measurement value av.

[0062] An example of a value above the threshold th2 is assumed to be a case where there are extremely few people in an office district on a holiday, causing a discrepancy between the predicted value and a predetermined measured value av. The reason for considering an example of a value above the threshold th2 is that it is assumed that in the future, the base station 10 will be able to control the throughput by increasing or decreasing it based on the predicted value. For example, if the throughput becomes too high, the base station 10 will control the throughput to decrease.

[0063] S33: In process S32, if the throughput of the predetermined actual measurement value av is equal to or less than the threshold th1 or equal to or greater than the threshold th2 (YES), the prediction value correction unit 25 calculates a corrected prediction value by averaging the prediction value acquired from the wireless quality prediction unit 23 and the predetermined actual measurement value av of the handover destination acquired from the actual measurement value utilization determination unit 24. For example, if the throughput in the predicted value is 8 Mbps and the throughput in the predetermined actual measurement value av is 2 Mbps, the prediction value correction unit 25 calculates 5 Mbps as the corrected prediction value.

[0064] S34: In process S32, if the throughput of the specified actual measurement value av is not equal to or less than the threshold th1 or equal to or more than the threshold th2, that is, if the throughput of the specified actual measurement value av is greater than the threshold th1 but less than the threshold th2 (NO), the predicted value correction unit 25 does not correct the predicted value using the specified actual measurement value av from the actual measurement value utilization determination unit 24, but instead uses the predicted value obtained from the wireless quality prediction unit 23 as the predicted value for the final prediction result.

[0065] Alternatively, the predicted value correction unit 25 may always correct the predicted value by using the predetermined actual measurement value av without performing steps S32 and S34. This is based on the idea that if the predetermined actual measurement value av is the latest value, the accuracy of the predicted value can be improved regardless of whether it is equal to or less than the threshold value th1 or equal to or more than the threshold value th2.

[0066] Furthermore, in process S32, if the throughput at the specified actual measurement value av is equal to or less than the threshold value th1 or equal to or greater than the threshold value th2 (YES), there is a discrepancy between the predicted value and the specified actual measurement value av, and therefore the predicted value correction unit 25 may use the specified actual measurement value av obtained from the actual measurement value utilization determination unit 24 as the predicted value as is as the prediction result, without using the predicted value obtained from the wireless quality prediction unit 23.

[0067] S35: After the process S33 or S34, the predicted value corrector 25 outputs the predicted result of the wireless quality of the handover destination.

[0068] By repeatedly executing the processes of Figures 3 and 13, according to this embodiment, it is possible to improve the accuracy of predicting deterioration in wireless quality due to handover in a wireless communication system 1 in which a base station 10 and a terminal 20 perform wireless communication.

[0069] [Hardware Configuration] Next, the hardware configuration of the terminal 20 will be described with reference to Fig. 13. Fig. 13 is a hardware configuration diagram of an electrical terminal (communication device) according to an embodiment. Note that the terminal 20 does not necessarily have to have the configuration shown in Fig. 13.

[0070] 13 , the terminal 20 includes a processor 1001, a memory 1002, an auxiliary storage device 1003, a communication device 1004, and a GPS (Global Positioning System) device 1005. The terminal 20 also includes an audio input device 1006, an audio output device 1007, a display device 1008, an imaging device 1009, a connection device 1010, and a near-field wireless communication device 1011. The hardware components constituting the terminal 20 are connected to each other via a bus 1020.

[0071] The processor 1001 serves as a control unit that controls the entire terminal 20, and includes various computing devices such as a CPU (Central Processing Unit). The processor 1001 reads various programs into the memory 1002 and executes them. The processor 1001 may include not only a CPU but also a GPU (Graphics Processing Unit).

[0072] The memory 1002 has a main storage device such as a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The processor 1001 and the memory 1002 form a so-called computer, and the processor 1001 executes various programs read onto the memory 1002, thereby enabling the computer to realize various functions.

[0073] The auxiliary storage device 1003 stores various programs and various information used when the various programs are executed by the processor 1001 .

[0074] The communication device 1004 is a communication device for transmitting and receiving various types of information to and from other devices (including equipment, servers, and systems). The GPS device 1005 detects the location information of the terminal 20.

[0075] The audio input device 1006 detects audio information such as the user's voice, surrounding sounds, etc. The audio output device 1007 is a device that outputs, by audio, various types of information received from other devices, for example.

[0076] The display device 1008 is a device that displays, for example, images of various information received from other devices.

[0077] The imaging device 1009 captures images of the user and the surroundings and generates image information.

[0078] The connection device 1010 is a connection device used when connecting various sensors, external memories, etc. to the terminal 20.

[0079] The short-range wireless communication device 1011 is a wireless device for performing short-range wireless communication with another device near the terminal 20 .

[0080] The server 40 has the same configuration as the terminal 20, and therefore a description thereof will be omitted. The server 40 may have at least the processor 1001, memory 1002, auxiliary storage device 1003, communication device 1004, connection device 1010, and bus 1020 from the configuration shown in FIG.

[0081] [Major 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.

[0082] Furthermore, when predicting the wireless quality of a handover destination, it is possible to suppress a decrease in the accuracy of the prediction of the wireless quality.

[0083] [Supplementary Note] The terminal 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.

[0084] 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.

[0085] 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.

[0086] REFERENCE SIGNS LIST 1 wireless communication system 10, 10a, 10b base station 20 terminal (an example of a communication device) 21 communication unit 22 handover destination prediction unit 23 wireless quality prediction unit 24 actual measurement value utilization determination unit 25 predicted value correction unit 40 server (an example of a predetermined server) 49 actual measurement value DB (an example of an actual measurement value management unit)

Claims

1. A communication device that performs wireless communication with a base station, comprising: a communication unit that transmits to a predetermined server actual measurement values ​​including identification information of the base station with which the communication device is communicating and wireless quality information indicating the wireless quality during communication; a handover destination prediction unit that predicts a predetermined base station as a handover destination based on the actual measurement values ​​in wireless communication with the current base station and the actual measurement values ​​of candidate handover destinations obtained from the predetermined server; a wireless quality prediction unit that predicts a change in wireless quality due to handover based on the actual measurement values ​​of an arbitrary communication device at the current base station obtained from the predetermined server and the actual measurement values ​​of the communication device at the current base station, and outputs a predicted value regarding wireless quality; and a predicted value correction unit that corrects the predicted value using a predetermined actual measurement value based on the actual measurement values ​​of the arbitrary communication device at the predetermined base station.

2. A communication device according to claim 1, comprising an actual measurement value utilization determination unit that determines whether the wireless quality related to the wireless quality information of the predetermined actual measurement value is equal to or less than a threshold, and if it is equal to or less than the threshold, determines to use the predetermined actual measurement value in the predicted value correction unit.

3. A communication method executed by a communication device that performs wireless communication with a base station, the method comprising: a communication process in which the communication device transmits to a predetermined server actual measurement values ​​including identification information of the base station with which the communication device is communicating and wireless quality information indicating the wireless quality during communication; a handover destination prediction process in which a predetermined base station to which the communication device will be a handover destination is predicted based on the actual measurement values ​​in wireless communication with the base station with which the communication device is communicating and the actual measurement values ​​of candidate handover destinations obtained from the predetermined server; a wireless quality prediction process in which a predicted value related to wireless quality is output by predicting a change in wireless quality due to handover based on the actual measurement values ​​of an arbitrary communication device at the predetermined base station with which the communication device is communicating and the actual measurement values ​​of the communication device at the base station with which the communication device is communicating; and a predicted value correction process in which the predicted value is corrected using a predetermined actual measurement value based on the actual measurement values ​​of the arbitrary communication device at the predetermined base station.

4. A program for causing a computer to execute the method according to claim 3.

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