Communication terminal, wireless communication system, wireless quality prediction method, and program

Abstract

This communication terminal performs wireless communication with one or more base stations, and includes: a performance value management unit that registers, in a database, performance values including the wireless quality of the wireless communication and the state of carrier aggregation (CA); a CA prediction unit that predicts a handover destination base station and the state of CA in the handover destination base station on the basis of the performance values registered in the database by a plurality of the communication terminals; and a wireless quality prediction unit that predicts the wireless quality at the time of handover to the handover destination base station on the basis of the performance values registered in the database and a result of the prediction by the CA prediction unit, and outputs the predicted wireless quality to a predetermined output destination.

Description

Communication terminal, wireless communication system, wireless quality prediction method, and program

[0001] The present invention relates to a communication terminal, a wireless communication system, a wireless quality prediction method, and a program.

[0002] There is a handover technique in a wireless communication system that supports Carrier Aggregation (CA) (see, for example, Non-Patent Documents 1 and 2). Also, a communication control method is known in which, on the receiver side of a wireless communication system having multiple propagation paths, movement of an obstacle is predicted and switching of the propagation paths is controlled (see, for example, Patent Document 1).

[0003] 3GPP TS 36.101 V18.4.0 (2023-12)3GPP TS 36.300 V18.0.0 (2023-12)

[0004] Japanese Patent Application Laid-Open No. 2020-92386

[0005] In a wireless communication system that supports CA, the state of CA changes with handover. However, conventional techniques do not take into account the state of CA after handover, which leads to a problem of reduced accuracy in predicting wireless quality after handover.

[0006] The embodiments of the present invention have been made in view of the above-mentioned problems, and improve the accuracy of predicting radio quality after handover in a radio communication system that supports CA.

[0007] In order to solve the above problem, a communication terminal according to an embodiment of the present invention is a communication terminal that performs wireless communication with one or more base stations, and includes: an actual value management unit that registers actual values ​​including the wireless quality of the wireless communication and the state of CA (Carrier Aggregation) in a database; a CA prediction unit that predicts a handover destination base station and the state of CA at the handover destination base station based on the actual values ​​registered in the database by multiple communication terminals; and a wireless quality prediction unit that predicts the wireless quality when handing over to the handover destination base station based on the actual values ​​registered in the database and the prediction result by the CA prediction unit, and outputs the predicted wireless quality to a predetermined output destination.

[0008] According to an embodiment of the present invention, it is possible to improve the accuracy of predicting radio quality after handover in a radio communication system that supports CA.

[0009] 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 communication terminal according to the present embodiment. FIG. 3 is a diagram 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 by a CA prediction unit according to the present embodiment. FIG. 5 is a diagram illustrating an example of a prediction process by a CA prediction unit according to the present embodiment. FIG. 6 is a diagram illustrating an example of a prediction process by a wireless quality prediction unit according to the present embodiment. FIG. 7 is a diagram illustrating an example of a prediction process by a wireless quality prediction unit according to the present embodiment.

[0010] 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.

[0011] <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 is a mobile communication system, such as 5G (5th Generation), that supports CA (Carrier Aggregation). CA is a technology that increases communication speeds by aggregating radio waves of multiple frequency bands for communication. Note that the wireless communication system 1 is not limited to 5G, and may be, for example, LTE (Long Term Evolution) or another mobile communication system that supports standards beyond 5G.

[0012] In the example of Fig. 1, the wireless communication system 1 includes one or more base stations 10a, 10b, ..., a communication terminal 20 that performs wireless communication with the one or more base stations 10a, 10b, ..., and an actual value DB (Database) 30 that can be accessed from the communication terminal 20. In the following description, when referring to any base station among the one or more base stations 10a, 10b, ..., the term "base station 10" is used. Also, the number of base stations 10 and the number of communication terminals 20 shown in Fig. 1 are examples. The number of base stations 10 and the number of communication terminals 20 may be any other number greater than or equal to two.

[0013] (Regarding the Issues) In mobile communication systems such as 5G or LTE, there is a limit to the area in which each base station can communicate, so handover (changing the base station with which the terminal communicates) occurs when the terminal moves. For example, in Fig. 1, when a communication terminal 20 moves from a communication area 11a of a base station 10a to a communication area 11b of a base station 10b, the communication terminal 20 performs handover from the base station 10a to the base station 10b.

[0014] In the wireless communication system 1 that supports CA, CA may be performed to improve communication quality, but all CAs are changed with handover (hereinafter referred to as HO). Therefore, for example, if CA is performed before HO and CA is not performed after HO, the wireless quality of the communication terminal 20 may deteriorate.

[0015] However, in conventional mobile communication systems, the base station determines whether to perform HO based on information received by the communication terminal, and does not determine whether CA will be performed at the base station to which the handover is to be made. This poses a problem in that the accuracy of predicting wireless quality after handover decreases.

[0016] Therefore, the communication terminal 20 according to this embodiment has, for example, the functional configurations shown in FIG. 2 in order to improve the prediction accuracy of the wireless quality after handover in a wireless communication system 1 that supports CA.

[0017] <Functional Configuration> Fig. 2 is a diagram showing an example of the functional configuration of a communication terminal according to this embodiment. As shown in Fig. 2, communication terminal 20 has functional components such as a wireless communication unit 201, a performance value management unit 202, a CA prediction unit 203, a wireless quality prediction unit 204, and a location information acquisition unit 205. Each of these functional components is realized, for example, by a program executed by one or more computers included in communication terminal 20. Note that at least a portion of the above functional components may be realized by hardware.

[0018] The communication terminal 20 is, for example, an information terminal such as a smartphone, a tablet terminal, etc. However, the communication terminal 20 is not limited to this, and may be, for example, a vehicle, a mobility scooter, a robot, a drone, or any other device capable of wireless communication with the base station 10.

[0019] The wireless communication unit 201 transmits and receives radio waves via the antenna 200, and executes wireless communication processing for transmitting and receiving data to and from one or more base stations 10 via wireless communication compatible with CA.

[0020] Based on the radio waves received by the wireless communication unit 201, the performance value management unit 202 registers performance values ​​including the wireless quality of wireless communication with each base station 10 and the state of Carrier Aggregation (CA) in the performance value DB 30. The performance value DB 30 is an example of a database. The performance value management unit 202 also acquires past performance values ​​registered in the performance value DB 30 by multiple communication terminals 20, and outputs them to the CA prediction unit 203, the wireless quality prediction unit 204, etc.

[0021] The CA prediction unit 203 executes a CA prediction process for predicting the handover destination base station 10 and the state of CA in the handover destination base station 10, based on the performance values ​​registered in the performance value DB 30 by the plurality of communication terminals 20. Details of the CA prediction process will be described later.

[0022] The wireless quality prediction unit 204 executes a wireless quality prediction process to predict the wireless quality when 10 handovers are made to the handover destination base station based on the actual values ​​registered in the actual value DB 30 and the prediction result by the CA prediction unit 203, and to output the predicted wireless quality to a predetermined output destination. For example, the wireless quality prediction unit 204 transmits the predicted result of the wireless quality when 10 handovers are made to the handover destination base station to the wireless communication unit 201, or to the base station 10 in wireless communication via the wireless communication unit 201. Details of the wireless quality prediction process will be described later.

[0023] The location information acquisition unit 205 executes a location information acquisition process to acquire location information indicating the location of the communication terminal 20. For example, the location information acquisition unit 205 acquires the location information of the communication terminal 20 using a GNSS (Global Navigation Satellite System) receiver or the like provided in the communication terminal 20. Note that the location information acquired by the location information acquisition unit 205 is assumed to be available to each of the wireless communication unit 201, the performance value management unit 202, the CA prediction unit 203, and the wireless quality prediction unit 204.

[0024] 2 is an example. For example, the functions of the performance value management unit 202 may be distributed among the wireless communication unit 201, the CA prediction unit 203, the wireless quality prediction unit 204, or the location information acquisition unit 205. The location information acquisition unit 205 is optional and not essential.

[0025] <Processing Flow> Next, the processing flow of the wireless quality prediction method according to this embodiment will be described.

[0026] (Actual value registration process) Fig. 3 is a flowchart showing an example of the actual value registration process according to this embodiment. This process shows an example of the actual value registration process executed when, for example, a communication terminal 20 having the functional configuration described in Fig. 2 is performing wireless communication with one or more base stations 10.

[0027] In step S301, the wireless communication unit 201 receives radio waves from one or more base stations 10 (for example, the base station 10 in wireless communication and surrounding base stations 10).

[0028] In step S302, the performance value management unit 202 acquires performance values ​​including the wireless quality and CA status of each base station 10 based on the radio waves received by the wireless communication unit 201. The wireless quality of each base station 10 includes information such as the RSRP (Reference Signal Received Power) of each base station 10 measured by the wireless communication unit 201 and the throughput of the base station 10 currently in communication. The CA status of the base station 10 also includes information indicating the presence or absence of CA (whether or not CA is being performed).

[0029] In step S303, the performance value management unit 202 registers the acquired performance values ​​in the performance value DB 30. For example, the performance value management unit 202 accesses the performance value DB 30 provided on the cloud via the wireless communication unit 201 and registers the performance values ​​in the performance value DB 30.

[0030] The communication terminal 20 included in the wireless communication system 1 repeatedly executes the process of Fig. 3. As a result, the performance value DB 30 accumulates performance values ​​registered by the plurality of communication terminals 20.

[0031] (Wireless Quality Prediction Process) Fig. 4 is a flowchart showing an example of wireless quality prediction process according to this embodiment. This process shows an example of wireless quality prediction process for predicting the wireless quality of a handover (HO) destination base station 10 when, for example, a communication terminal 20 having the functional configuration described in Fig. 2 is performing wireless communication with one or more base stations 10.

[0032] In step S401, the CA prediction unit 203 executes a CA prediction process to predict the HO destination base station 10 and the CA state at the HO destination base station 10, based on the performance values ​​registered in the performance value DB 30. Note that a specific example of the CA prediction process will be described later.

[0033] In step S402, the wireless quality prediction unit 204 executes a wireless quality prediction process to predict the wireless quality when HO is performed to the HO-destination base station 10, based on the actual value registered in the actual value DB 30 and the prediction result by the CA prediction unit 203. Note that a specific example of the wireless quality prediction process will be described later.

[0034] In step S403, the wireless quality prediction unit 204 outputs the prediction result of the wireless quality of the handover destination base station 10 to a predetermined output destination. For example, the wireless quality prediction unit 204 transmits the prediction result to the wireless communication unit 201 or to the base station 10 via the wireless communication unit 201.

[0035] By the processing of Figure 4, the communication terminal 20 can predict the presence or absence of CA at the HO destination and predict the radio quality after HO taking into account the presence or absence of CA at the HO destination, thereby improving the prediction accuracy of the radio quality after handover.

[0036] <Prediction Processing by CA Prediction Unit> In this embodiment, the following first to third methods are assumed for the prediction processing by the CA prediction unit 203. However, the prediction processing by the CA prediction unit 203 may use a method different from the first to third methods.

[0037] (First Method) In the first method, the CA prediction unit 203 predicts, from the communication status of the HO destination, the HO destination base station 10 and the state of the CA in the HO destination base station 10. The first method assumes a case where multiple communication terminals 20 and the performance value DB 30 cooperate in real time due to the introduction of a specific application or the like.

[0038] As an example, it is assumed that CA prediction unit 203 has acquired current RSRP actual measurement value 501 of communication terminal 20 as shown in Fig. 5A from wireless communication unit 201. It is also assumed that CA prediction unit 203 has acquired past CA actual value 502 as shown in Fig. 5B from actual value management unit 202.

[0039] Here, the actual value 502 indicates, for example, that the RSRP value when CA (and HO) was previously performed at base station A was −90 dBm, and that the RSRP value when CA was previously performed at base station B was −85 dBm. Also, RSRP is the received power value of a reference signal that is determined by the positional relationship between communication terminal 20 and base station 10, regardless of traffic in the wireless section.

[0040] In the first method, CA prediction unit 203 predicts that CA will occur when the RSRP value from base station 10, which is the CA destination (HO destination), is equal to or greater than a predetermined value. In the example of Fig. 5B, CA prediction unit 203 predicts that communication terminal 20 will HO to base station A and perform CA when the actual measured value of RSRP of base station A is equal to or greater than -90 dBm, which is the actual CA value of base station A. Furthermore, CA prediction unit 203 predicts that communication terminal 20 will HO to base station B and perform CA when the actual measured value of RSRP of base station B is equal to or greater than -95 dBm, which is the CA actual value of base station B.

[0041] In the examples of Figures 5A and 5B, the actual measured value of RSRP of base station A is -95 dBm, which is lower than the actual value of CA of base station A, -90 dBm. Also, the actual measured value of RSRP of base station B is -85 dBm, which is higher than the actual value of CA of base station B, -95 dBm. In this case, CA prediction unit 203 predicts that communication terminal 20 will HO to base station B and perform CA. Note that here, it is assumed that the data stored in actual value DB 30, the prediction results, and the required communication volume cannot be covered by a single frequency band, and therefore CA must be performed.

[0042] In this way, in the first method, the CA prediction unit 203 predicts the HO destination base station 10 and the CA state at the HO destination base station 10 based on the current wireless quality of each base station 10 and the actual values ​​of past CA.

[0043] When CA is not performed, the CA prediction unit 203 may predict the HO to the HO-destination base station 10 based on the past HO performance value in the case where CA is not performed, instead of the past CA performance value 502 as shown in Fig. 5B. When CA is sometimes performed in the HO-destination base station 10 and sometimes not performed, the CA prediction unit 203 may calculate the probability that CA will be performed (hereinafter referred to as CA probability) and output the prediction result.

[0044] (Second Method) In the second method, the CA prediction unit 203 predicts the HO destination base station 10 and the state of CA at the HO destination base station 10, based on location information indicating the current location of the communication terminal 20 and the results of HO and CA at the current location. The second method assumes that the communication terminal 20 has location information available from GNSS or the like.

[0045] 6 , CA prediction unit 203 acquires location information from location information acquisition unit 205, which indicates that point X, where wireless communication with base station A and base station B is possible, is the current location of communication terminal 20. CA prediction unit 203 also acquires from performance value management unit 202 past performance values ​​of CA performed with base station B near point X.

[0046] In this case, the CA prediction unit 203 predicts, based on past performance values, that the communication terminal 20 will HO to the base station B at the point X and perform CA. Note that, here, it is assumed that the data stored in the performance value DB 30, the prediction results, and the required communication volume cannot be covered by one frequency band, and therefore it is necessary to perform CA.

[0047] When CA prediction unit 203 acquires from performance value management unit 202 a performance value of HO without CA with base station B near point X, CA prediction unit 203 may predict that communication terminal 20 will HO to base station B at point X and will not perform CA. When there are multiple performance records of HO with CA and HO without CA at point X, CA prediction unit 203 may calculate a CA probability and output it as a prediction result.

[0048] Thus, in the second method, the CA prediction unit 203 predicts the state of the base station 10 to be HO'ed and the CA at the base station 10 to be HO'ed, based on location information indicating the current location of the communication terminal 20, and past HO and CA performance at the current location.

[0049] (Third Method) In the third method, the first method and the second method are combined to predict the state of the HO-destination base station 10 and the CA at the HO-destination base station 10. In the third method, it is assumed that, for example, by introducing a specific application, the multiple communication terminals 20 and the performance value DB 30 are linked in real time, and that the communication terminals 20 are able to use location information from GNSS or the like.

[0050] In the third method, similarly to the first method, the CA prediction unit 203 predicts the HO-destination base station 10 and the state of CA at the HO-destination base station 10 from the acquired wireless quality of each base station 10 and the past HO and CA performance values. Also, similarly to the second method, the CA prediction unit 203 predicts the HO-destination base station 10 and the state of CA at the HO-destination base station 10 from the past HO and CA performance values ​​at the current location of the communication terminal 20.

[0051] As an example, it is assumed that CA prediction unit 203 has acquired actual measured value 501 of the current RSRP of communication terminal 20, as shown in Fig. 5A, from wireless communication unit 201. It is also assumed that CA prediction unit 203 has acquired past CA actual value 502, as shown in Fig. 5B, from actual value management unit 202. It is also assumed that CA prediction unit 203 has acquired, from location information acquisition unit 205, point X, at which wireless communication with base station A and base station B is possible, as location information indicating the current location of communication terminal 20, as shown in Fig. 6.

[0052] In this case, the CA prediction unit 203 combines the first method and the second method to predict that the communication terminal 20 will HO to the base station B and perform CA at the point X. Note that the CA prediction unit 203 may determine the priority of the first method and the second method, and, for example, predict the HO-destination base station 10 and the state of CA at the HO-destination base station 10 by the first method when there is no past record of HO and CA occurring at the current location by the second method. Note that here, it is assumed that the data stored in the performance value DB 30, the prediction results, and the required communication volume cannot be covered by a single frequency band and therefore CA must be performed.

[0053] <Prediction Processing by Wireless Quality Prediction Unit> In this embodiment, the following first and second methods are assumed for the prediction processing by the wireless quality prediction unit 204. However, the prediction processing by the wireless quality prediction unit 204 may use a method different from the following first and second methods.

[0054] (First Method) In the first method, the wireless quality prediction unit 204 determines whether to perform CA based on the predicted CA result or the CA probability and a threshold, and predicts the wireless quality. For example, when the predicted result by the CA prediction unit 203 is the CA probability (the probability that CA will be performed), the wireless quality prediction unit 204 determines whether to perform CA based on the CA probability and a predetermined threshold.

[0055] 7 , when the prediction result by the CA prediction unit 203 is a CA probability of 80% and the threshold is 50%, the wireless quality prediction unit 204 determines that CA is performed because the CA probability is equal to or greater than the threshold. On the other hand, when the prediction result by the CA prediction unit 203 is a CA probability of 40% and the threshold is 50%, the wireless quality prediction unit 204 determines that CA is not performed because the CA probability is less than the threshold. Note that the prediction result by the CA prediction unit 203 is not limited to a CA probability, and may indicate whether or not CA is performed.

[0056] Furthermore, when it is determined that CA is performed, the wireless quality prediction unit 204 outputs an average value or a percentile value as a predicted result of wireless quality from the actual values ​​of wireless quality with CA obtained from the actual value management unit 202. For example, as shown in Fig. 7 , the wireless quality prediction unit 204 creates a graph 700 in which the horizontal axis represents throughput with CA and the vertical axis represents the number of actual results. Furthermore, the wireless quality prediction unit 204 outputs a throughput corresponding to a predetermined percentile value set in advance (8 Mbps in the example of Fig. 7 ) as the wireless quality after handover when CA is performed.

[0057] Similarly, when the wireless quality prediction unit 204 determines that CA is not present, it outputs the average value or percentile value from the actual values ​​of wireless quality without CA obtained from the actual value management unit 202 as the predicted result of wireless quality.

[0058] (Second Method) In the second method, the wireless quality prediction unit 204 predicts the wireless quality when handing over to the destination base station 10 based on the predicted result of CA, by taking a weighted average of the predicted value of wireless quality when CA is present and the predicted result of CA when CA is not present.

[0059] For example, as shown in Fig. 8, the wireless quality prediction unit 204 creates a graph 801 in which the horizontal axis represents throughput with CA and the vertical axis represents the number of actual cases, and sets a predetermined percentile value of 8 Mbps as the predicted value of wireless quality after handover in the case of CA. Also, as shown in Fig. 8, the wireless quality prediction unit 204 creates a graph 802 in which the horizontal axis represents throughput without CA and the vertical axis represents the number of actual cases, and sets a predetermined percentile value of 3 Mbps as the predicted value of wireless quality after handover in the case of no CA.

[0060] Furthermore, when the prediction result by the CA prediction unit 203 is a CA probability of 80%, the wireless quality prediction unit 204 calculates a predicted value of wireless quality by a weighted average, assuming that the probability of CA is 80% and the probability of no CA is 20%. In the example of Fig. 8, the predicted value of wireless quality is Predicted value = 8 x 0.8 + 3 x 0.2 = 7 (Mbps).

[0061] <Hardware Configuration> The communication terminal 20 according to this embodiment has, for example, the hardware configuration of a computer 900 as shown in FIG.

[0062] Fig. 9 is a diagram showing an example of the hardware configuration of a computer. In the example of Fig. 9, the computer 900 includes a processor 1001, a memory 1002, a storage device 1003, a communication I / F 1004, an input device 1005, an output device 1006, and a bus B. In addition, when acquiring position information, the computer 900 may further include a GNSS receiver or the like.

[0063] The processor 1001 is, for example, an arithmetic unit such as a CPU (Central Processing Unit) that executes predetermined programs to realize various functions. The memory 1002 is a storage medium readable by the computer 900, and includes, for example, a RAM (Random Access Memory) and a ROM (Read Only Memory). The storage device 1003 is a large-capacity storage medium readable by the computer, and may include, for example, a HDD (Hard Disk Drive), an SSD (Solid State Drive), various optical disks, and magneto-optical disks.

[0064] The communication I / F 1004 is an interface for communicating with other devices via a wireless or wired network. The input device 1005 is an input device that accepts input from the outside and may include, for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc. The output device 1006 is an output device that outputs to the outside and may include, for example, a display, a speaker, an LED lamp, etc.

[0065] The bus B is commonly connected to the above components and transmits, for example, address signals, data signals, and various control signals. The processor 1001 may be, in addition to (or instead of) a CPU, a digital signal processor (DSP), a programmable logic device (PLD), a field programmable gate array (FPGA), or the like.

[0066] The program executed by the computer 900 may be for realizing some of the functions described above, or may be capable of realizing the functions described above in combination with a program already stored in the computer 900. Furthermore, some or all of the functional configuration of each device may be realized using hardware such as a PLD or FPGA.

[0067] (Supplementary Note) The communication terminal 20 in this embodiment is not limited to being realized by a dedicated device, but may also be realized by a general-purpose computer. 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. Note that the term "computer system" here includes hardware such as an OS and peripheral devices.

[0068] Furthermore, the term "computer-readable recording medium" includes various storage devices such as portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices 2103 built into computer systems. Furthermore, the term "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.

[0069] 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.

[0070] According to the present embodiment, in a wireless communication system supporting CA, it is possible to improve the prediction accuracy of wireless quality after handover. Specifically, the communication terminal 20 according to the present embodiment predicts whether or not CA is present at the HO destination and predicts the wireless quality after HO taking into account the presence or absence of CA, thereby improving the prediction accuracy of the wireless quality after HO.

[0071] Summary of Embodiments This specification discloses at least the following communication terminals, wireless communication systems, wireless quality prediction methods, programs, etc.: (Item 1) A communication terminal that performs wireless communication with one or more base stations, comprising: a performance value management unit that registers performance values ​​including the wireless quality of the wireless communication and a Carrier Aggregation (CA) state in a database, a CA prediction unit that predicts a handover destination base station and a CA state at the handover destination base station based on the performance values ​​registered in the database by multiple communication terminals, and a wireless quality prediction unit that predicts wireless quality when handing over to the handover destination base station based on the performance values ​​registered in the database and the prediction result by the CA prediction unit, and outputs the predicted wireless quality to a predetermined output destination. (Clause 2) A wireless communication system including a communication terminal that performs wireless communication with one or more base stations and a database accessible from the communication terminal, wherein the communication terminal has: an actual value management unit that registers actual values ​​including the wireless quality of the wireless communication and the state of CA in the database; a CA prediction unit that predicts a handover destination base station and the state of CA at the handover destination base station based on the actual values ​​registered in the database by multiple communication terminals; and a wireless quality prediction unit that predicts the wireless quality when handing over to the handover destination base station based on the actual values ​​registered in the database and the prediction result by the CA prediction unit, and outputs the predicted wireless quality to a specified output destination. (Clause 3) A wireless quality prediction method in which a communication terminal that performs wireless communication with one or more base stations performs the following steps: a process of registering actual values ​​including the wireless quality of the wireless communication and the state of CA in a database; a CA prediction process of predicting a handover destination base station and the state of CA at the handover destination base station based on the actual values ​​registered in the database by multiple communication terminals; and a process of predicting the wireless quality when handing over to the handover destination base station based on the actual values ​​registered in the database and the prediction result by the CA prediction unit, and outputting the result to a specified output destination.(4) A program for causing a communication terminal to execute the communication method described in 3, or a storage medium storing the program.

[0072] 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.

[0073] REFERENCE SIGNS LIST 1 Wireless communication system 10, 10a, 10b Base station 20 Communication terminal 30 Performance value DB (database) 201 Wireless communication unit 202 Performance value management unit 203 CA prediction unit 204 Wireless quality prediction unit 205 Location information acquisition unit 900 Computer

Claims

1. A communication terminal that performs wireless communication with one or more base stations, comprising: a performance value management unit that registers performance values ​​including the wireless quality of the wireless communication and the state of CA (Carrier Aggregation) in a database; a CA prediction unit that predicts the base station to which a handover will be made and the state of CA at the base station to which a handover will be made, based on the performance values ​​registered in the database by multiple communication terminals; and a wireless quality prediction unit that predicts the wireless quality when a handover is made to the base station to which a handover will be made, based on the performance values ​​registered in the database and the prediction result by the CA prediction unit, and outputs the predicted wireless quality to a specified output destination.

2. A wireless communication system including a communication terminal that performs wireless communication with one or more base stations and a database accessible from the communication terminal, wherein the communication terminal has: an actual value management unit that registers actual values ​​including the wireless quality of the wireless communication and the state of CA in the database; a CA prediction unit that predicts the base station to which a handover will be made and the state of CA at the base station to which a handover will be made, based on the actual values ​​registered in the database by multiple communication terminals; and a wireless quality prediction unit that predicts the wireless quality when a handover is made to the base station to which a handover will be made, based on the actual values ​​registered in the database and the prediction result by the CA prediction unit, and outputs the predicted wireless quality to a specified output destination.

3. A wireless quality prediction method in which a communication terminal that performs wireless communication with one or more base stations performs the following steps: registering actual values ​​including the wireless quality of the wireless communication and the state of CA in a database; CA prediction processing that predicts the base station to which a handover will be made and the state of CA at the base station to which a handover will be made, based on the actual values ​​registered in the database by multiple communication terminals; and predicting the wireless quality when a handover is made to the base station to which a handover will be made, based on the actual values ​​registered in the database and the prediction result of the CA prediction processing, and outputting the result to a specified output destination.

4. A program for causing a communication terminal to execute the wireless quality prediction method according to claim 3.

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