Terminal, base-station device, wireless communication system, and control method and program thereof

Abstract

Providing techniques for flexibly configuring CHO execution conditions SOLUTION: The terminal apparatus receives, from the base station apparatus to which the terminal apparatus is currently connected, preconfiguration for handover to another base station apparatus, the preconfiguration including a first condition, a second condition different from the first condition, and first information designating a logical operation of the first condition and the second condition, determines whether or not to perform handover to the other base station apparatus based on the preconfiguration, and performs handover to the other base station apparatus in accordance with a result of the determination.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a terminal device, a base station device, a wireless communication system, and a control method and program thereof. [Background technology]

[0002] For the fifth-generation mobile communication system (5G) and sixth-generation mobile communication system (6G), the integration of low-earth orbit (LEO) satellites and mobile networks is being considered. This integrated network is called the Non-Terrestrial Network (NTN). LEO satellites are now operating in a regenerative mode, where they function as base stations and communicate with other LEO satellites via Inter Satellite Links (ISLs), rather than in a transparent mode, where they act as repeaters that relay radio waves. In regenerative mode, LEO satellites function as base stations and accommodate user equipment (UE) within the cell area they provide service to.

[0003] Non-Patent Document 1 discloses conditional handover (CHO) in which a user equipment (UE) executes a handover (HO) when it determines that a handover condition is met in a New Radio (NR) and a NG Radio Access Network (NG-RAN). In CHO, evaluation of the HO execution condition begins when a CHO setting is received from a base station device, and the UE executes HO when the condition is met. Non-Patent Document 2 defines the CHO execution condition. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP TS 38.300 V18.1.0, "3rd Generation Partnership Project;Technical Specification Group Radio Access Network; NR and NG-RAN Overall description; (Release 18)" [Non-patent document 2] 3GPP TS 38.331 V18.1.0, "3rd Generation Partnership Project;Technical Specification Group Radio Access Network; NR; Radio Resource Control (RRC) protocol specification (Release 18)" Summary of the Invention [Problem to be solved by the invention]

[0005] However, the inability to flexibly set the execution conditions for CHO was an issue. [Means for solving the problem]

[0006] The present invention has been made in view of the above-mentioned problems, and aims to provide a technique for flexibly setting the execution conditions of CHO.

[0007] A terminal device according to one aspect of the present invention comprises: a receiving means for receiving a pre-setting for handover from a currently connected base station device to another base station device, the pre-setting including a first condition, a second condition different from the first condition, and first information specifying a logical operation of the first and second conditions; a determination means for determining whether or not to execute a handover to the other base station device based on the preset setting; an execution means for executing a handover to the other base station device in accordance with a determination result of the determination means; The present invention is characterized by comprising: [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a technique for flexibly setting the execution conditions of CHO. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a configuration of a wireless communication system according to an embodiment of the present invention. [Figure 2] (A) Configuration diagram of satellite base station equipment, (B) Configuration diagram of terminal equipment [Figure 3] (A) Conceptual diagram of cell area layout, (B) Conceptual diagram of satellite base station equipment providing services in multiple cell areas over time [Figure 4] (A) to (C) are diagrams showing the pre-settings that notify the execution conditions of CHO. [Figure 5] 1A is a flowchart showing an example of processing executed by a terminal device, and FIG. 1B is a flowchart showing an example of processing executed by a satellite base station device. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be combined in any desired manner. Furthermore, the same reference numerals are used to designate identical or similar components, and redundant descriptions will be omitted.

[0011] <System configuration> The configuration of a wireless communication system according to this embodiment is explained with reference to Fig. 1. The wireless communication system 1 shown in Fig. 1 comprises satellite base station devices 101 to 10 N (hereinafter, they may be referred to as satellite base station device 10 without distinction) and a terminal device 20.

[0012] The satellite base station device 10 can communicate with the core network 40 via the ground station 30. In this embodiment, the satellite base station device 10 will be described as a low earth orbit satellite (LEO) that can operate as a base station device. The satellite base station device 10 functions as a base station device and provides services to terminal devices 20 located on the ground. In this embodiment, the satellite base station device 10 can communicate with the ground station 30 and other satellite base station devices 10.

[0013] The terminal device 20 can connect to the satellite base station device 10 via a cell formed by one of the satellite base station devices 10. In this embodiment, the terminal device 20 will be described as user equipment (UE) such as a smartphone located on the ground.

[0014] It should be noted that the wireless communication system 1 is only required to include two or more satellite base station devices 10 and one or more terminal devices 20, and there is no limit to the number of satellite base station devices 10 and terminal devices 20. Furthermore, although the present embodiment will be described taking the satellite base station device 10 as an example, the terminal device 20 may be connected to a base station device located on the ground.

[0015] <Hardware configuration> 2A shows a hardware configuration diagram of satellite base station device 10. Satellite base station device 10 includes wireless communication unit 101, control unit 102, beam control unit 103, and antenna 104.

[0016] The wireless communication unit 101 performs wireless communication with a terrestrial station or a terminal device 20 via an antenna 104. In this embodiment, the wireless communication unit 101 is capable of performing communication in accordance with the fifth generation (5G) standard defined by the Third Generation Partnership Project (3GPP (registered trademark)) or a successor standard to 5G, such as sixth generation (6G). The satellite base station device 10 also functions as a base station device (gNB) conforming to the 5G standard or a standard beyond 5G.

[0017] The control unit 102 includes one or more processors and controls the overall operation of the satellite base station device 10 by executing programs stored in a ROM (Read Only Memory) or a RAM (Random Access Memory). The beam control unit 103, as will be described later, controls the beam direction of the antenna 104 so as to provide service to terminal devices located within a predetermined terrestrial range (cell area). If the antenna 104 includes multiple antennas, the beam control unit 103 may control the beam direction by adjusting the phases of electromagnetic waves transmitted from the multiple antennas, or by controlling the attitude of the satellite base station device 10. The antenna 104 includes one or more antennas and communicates with terrestrial terminal devices 20. The beam control unit 103 is also capable of controlling the directivity of the antenna 104 or the attitude of the satellite base station device 10 to enable communication with a terrestrial station 30 or another satellite base station device 10. In one example, the antenna 104 may include multiple antennas and be capable of simultaneously communicating with multiple terminal devices 20, terrestrial stations 30, and another satellite base station device 10. Furthermore, the antenna 104 may include a plurality of antennas 104 so as to be capable of transmitting and receiving electromagnetic waves in a plurality of frequency bands.

[0018] 2B shows a hardware configuration diagram of the terminal device 20. The terminal device 20 includes a wireless communication unit 201, a control unit 202, and an antenna 203.

[0019] The wireless communication unit 201 performs wireless communication with the satellite base station device 10 via an antenna 203. In this embodiment, the wireless communication unit 201 is assumed to be capable of performing communication in accordance with the fifth generation (5G) standard defined by the Third Generation Partnership Project (3GPP (registered trademark)) or a successor standard to 5G, such as sixth generation (6G). The terminal device 20 is assumed to function as user equipment (UE) of the 5G or successor standard to 5G.

[0020] The control unit 202 includes one or more processors and controls the overall operation of the terminal device 20 by executing a program recorded in a ROM (Read Only Memory) or a RAM (Random Access Memory). The antenna 203 includes one or more antennas and communicates with the satellite base station 10. The terminal device 20 may also be capable of communicating with a terrestrial base station device (not shown). The antenna 104 includes one or more antennas and communicates with the satellite base station device 10. In one example, the terminal device 20 may be capable of communicating with terrestrial cellular base stations and other terminal devices 20 in addition to the satellite base station device 10.

[0021] <Satellite placement example> 3(A) shows an example of the arrangement of satellite base station devices 10. The satellite base station devices 10 according to this embodiment are arranged at predetermined intervals so that the cells arranged on the ground are arranged at equal intervals. Note that the cells arranged on the ground may partially overlap, and after a given satellite base station device 10 finishes providing service in a given location range (cell area), another satellite base station device 10 begins providing service in that cell area. In this way, it becomes possible for a terminal device 20 to connect to any of the satellite base station devices 10 in multiple cell areas arranged on the ground.

[0022] In this embodiment, the cell areas are assumed to be of equal size as shown in FIG. 3A. However, this is not limiting, and it is sufficient that the timing at which service provision in a given cell area by one satellite base station device 10 will end can be determined by the satellite base station device 10 that will provide service in that cell area after the satellite base station device 10. For example, the satellite base station device 10 can determine the timing at which service provision by the satellite base station device 10 will end by grasping the location information of the cell area and the locations and cruising speeds of the multiple satellite base station devices 10. However, if the cell areas are of equal size and the multiple satellite base station devices 10 cruise at the same cruising speed and at equal intervals, the satellite base station device 10 can predict that the multiple satellite base station devices 10 will end provision of service in the cell area at the same time intervals. Therefore, it is possible to predict the occurrence of a handover due to the movement of the satellite base station device 10 based only on the elapsed time since the previous handover, without grasping the location of the satellite base station device 10.

[0023] FIG. 3B shows a conceptual diagram of the satellite base station device 10 according to this embodiment providing services in a plurality of adjacent cells while moving.

[0024] At time t1, satellite base station device 10 begins providing service in first cell area 301. Then, during the period up to time t1+Δt, beam control or attitude control of satellite base station device 10 is performed to move the directivity of antenna 104 so that it continues to cover cell area 302. Multiple satellite base station devices 10 are placed on a single orbit, and the spacing between satellite base station devices 10 on the same orbit, for example, the distance in the longitude direction, is equal to the length of the cell in the longitude direction. This makes it possible to provide continuous service in the cell area with a small number of satellite base station devices 10.

[0025] Here, compared to electromagnetic waves transmitted from terrestrial base station devices, the difference between the received signal strength of a terminal device at the center of a cell area and the received signal strength of a terminal device at the edge of the cell area (cell edge) is small for electromagnetic waves transmitted from satellite base station device 10. This is known as the near-far effect. In a situation where such a near-far effect occurs, unlike terrestrial base station devices, there are cases where the terminal device cannot determine that it is located at the cell edge based on the received signal strength, i.e., the terminal device needs to perform handover based on the received signal strength.

[0026] To deal with such a situation, CondEvents D1, D2, and T1 were defined as new execution conditions for CHO.

[0027] CondEvent D1 executes HO when the distance from reference position 1 becomes greater than a predefined first threshold and the distance from reference position 2 becomes smaller than a predefined second threshold. CondEvent D2 also executes HO when the distance from reference position 1 becomes greater than the first threshold and the distance from reference position 2 becomes smaller than the second threshold, but unlike D1, it is assumed that reference positions 1 and 2 will move. CondEvent T1 executes HO when the time measured by the UE exceeds the first threshold and is smaller than a second threshold that is greater than the first threshold.

[0028] Such execution conditions are transmitted between the terminal device and the satellite base station device to which the terminal device is connected, using an RRC Reconfiguration message, for each satellite base station device that provides a cell that is a candidate for HO.

[0029] Here, the CHO described in Non-Patent Document 1 has many limitations and lacks flexibility, which is an issue. For example, the existing CHO can only set up to two different types of execution conditions, such as CondEvent A3 and D1, as the execution conditions for executing HO for one candidate cell (Constraint 1). Also, the existing CHO cannot simultaneously set CondEvent D1 and CondEvent T1 as trigger conditions (Constraint 2). Also, when two types of execution conditions are set, the existing CHO can only execute the CHO if both of the two execution conditions are satisfied (Constraint 3).

[0030] In this embodiment, a technique for improving the flexibility of CHO is provided by introducing a CHO process that does not require at least one of the above-mentioned constraints 1 to 3.

[0031] <Handover type> In this embodiment, the satellite base station device 10 orbits in a low earth orbit, and therefore the provision of service in the same cell area may be terminated due to the movement of the satellite base station device 10. Also, the terminal device 20 may move and leave the cell area. That is, handover of the terminal device 20 may occur due to the movement of the terminal device 20 itself or the movement of the satellite base station device 10.

[0032] When a handover occurs due to movement of the terminal device 20, the terminal device 20 moves away from a predetermined point such as the center of a first cell area provided by the satellite base station device 10 and approaches the center of a cell area provided by another satellite base station device 10. Therefore, the center of the first cell area provided by the satellite base station device 10 is set as a first reference position, and the distance from the first reference position to the terminal device 20 exceeds a first threshold. A predetermined point such as the center of a second cell area provided by another satellite base station device 10 is set as a second reference position, and the distance from the second reference position to the terminal device 20 exceeds the second threshold. This enables handover to a neighboring cell. In other words, when a handover occurs due to movement of the terminal device 20, an appropriate response can be made by performing handover using CondEvent D1 as the execution condition.

[0033] On the other hand, when a handover occurs due to the movement of the satellite base station device 10, even if the terminal device 20 is not moving, the satellite base station device 10 may travel over time and the cell area covered by the satellite base station device 10 may change, causing a handover. Cases caused by the movement of the satellite base station device 10 may include cases where the satellite base station device 10 moves relative to the ground due to the rotation of the Earth, and cases where the satellite base station device 10 travels.

[0034] For the purpose of explanation, assume that 11 satellite base station devices 10 are arranged in each of six orbital planes. In this case, a 6 × 11 cell arrangement is assumed, with six cells arranged in the longitude direction and 11 cells arranged in the latitude direction. It is also assumed that the satellite base station devices 10 travel in the latitude direction at a speed of 7.5 km / s, as shown in FIG. 3. In this case, assuming that the circumference of the Earth is 40,000 km, the cell served by each satellite base station device 10 is switched every (40,000 / 11) / 7.5 ≒ 485 seconds, i.e., approximately every 8 minutes in the latitude direction (north-south direction). On the other hand, assuming that the rotation speed is 0.4651 km / s, the cell served by each satellite base station device 10 is switched every (40,000 / 6) / 0.4651 ≒ 14,360 seconds in the longitude direction (east-west direction), i.e., approximately every 240 minutes in the longitude direction.

[0035] Therefore, when a handover occurs due to the movement of the satellite base station device 10, the provision of service by the satellite base station device 10 in a specified cell area will end after a specified time has elapsed, so an appropriate response can be made by performing a handover using CondEvent T1 as the execution condition.

[0036] In this way, when the terminal device 20 is connected to the satellite base station device 10, by setting the execution condition to execute handover when either CondEvent D1 or CondEvent T1 is satisfied, it is possible to deal with cases where handover occurs due to movement of either the satellite base station 10 or the terminal device 20. However, in the standard defined in Non-Patent Document 2, CondEvent D1 and CondEvent T1 cannot be set as execution conditions for CHO. Also, it is not possible to set CHO to be executed when either of the execution conditions is satisfied.

[0037] Furthermore, existing standards allow only a maximum of two execution conditions to be set, so if CondEvent D1 and CondEvent T1 are set, such as at the edge of a cell area, handover cannot be executed under other conditions, and handover cannot be executed when, for example, the communication quality with another satellite base station device 10 becomes better than the communication quality with the currently connected satellite base station device 10.

[0038] To solve at least one of the above-described problems, the wireless communication system 1 according to this embodiment notifies a new handover execution condition.

[0039] FIG. 4 shows the structure of the condExecutionCond information element (IE), which is a pre-setting used by the satellite base station device 10 according to this embodiment to set a CondEvent in the terminal device 20. IE 401 in FIG. 4A shows the structure of the condExecutionCond-r16, which is a conventional IE for sending a list of two execution conditions (MeasId). IE 411 in FIG. 4B shows the structure of the condExecutionCond-r16 according to this embodiment. In addition to the conventional list of execution conditions, IE 411 introduces a logicOperator that specifies a logical operator for the execution condition. The logicOperator can specify whether to perform a logical product (AND) or logical sum (OR) operation on the two execution conditions. Note that the logicOperator may also specify other operators such as NAND, NOR, or XOR in addition to or instead of AND and OR.

[0040] An example of a condExecutionCond IE is shown in FIG. 4(C). IE 422 enclosed by a dashed line in FIG. 4(C) indicates that CondEvents A1 and D1 are ANDed. That is, the execution condition indicated by IE 422 is determined to be satisfied when execution conditions A1 and D1 are satisfied. Similarly, IE 423 indicates that condition 422 and CondEvent T1 are ORed. And overall condition 421 indicates that condition 423 and CondEvent A3 are ANDed. Therefore, the terminal device 20 that has received the IE shown in FIG. 4(C) executes a handover when the following logical formula is satisfied. Note that in the following logical formula, "&&" indicates a logical product, and "||" indicates a logical sum.

[0041] ((CondEvent A1 && CondEvent D1) || CondEvent T1) && CondEvent A3 In this way, by transmitting two or more execution conditions and information indicating the logical operation of these execution conditions, it becomes possible to flexibly set the conditions for executing CHO.

[0042] Furthermore, as shown in IE 421 in Fig. 4(C), by transmitting three or more execution conditions and information indicating a logical operation of these execution conditions in one RCC Reconfiguration message, it is possible to flexibly configure the CHO settings in the terminal device 20 without transmitting multiple RCC Reconfiguration messages. Note that the RRC Reconfiguration message is intended to set the conditions for executing handover for one candidate base station device that is the handover destination. However, execution conditions for each of multiple HO candidate base station devices may be transmitted in one RRC Reconfiguration message.

[0043] Furthermore, the execution conditions may be set by the handover candidate satellite base station device 10, or may be set by the handover source satellite base station device 10. When the execution conditions are set by the handover candidate satellite base station device 10, the handover source satellite base station device 10 may receive information specifying the execution conditions from the handover candidate satellite base station device 10 via communication between satellite base station devices.

[0044] <Processing example> Fig. 5(A) shows an example of processing executed by the terminal device 20 according to this embodiment. The processing shown in Fig. 5(A) is realized by the processor of the terminal device 20 executing a program stored in memory. Note that the processing shown in Fig. 5(A) will be explained assuming that it is executed when the terminal device 20 connects to the satellite base station device 10.

[0045] In S501, the terminal device 20 determines whether or not it has received, from the satellite base station device 10, an RRC Reconfiguration message that sets conditions for executing handover as pre-settings for executing CHO. If it is determined that an RRC Reconfiguration message has been received (Yes in S501), the terminal device 20 proceeds to processing in S502 and determines whether or not the execution conditions included in the RRC Reconfiguration message have been satisfied. Here, the CHO execution conditions determined in S502 are based on two or more execution conditions included in the RRC Reconfiguration message and information indicating a logical operation of these execution conditions. If it is determined in S501 that an RRC Reconfiguration message has not been received (No in S501), the terminal device 20 proceeds to processing in S503, does not execute CHO, transmits a measurement report to the satellite base station device 10, and executes handover in accordance with the handover instruction from the satellite base station device 10. In another example, in S503, the terminal device 20 may return the process to S501 and wait until it receives an RRC Reconfiguration message from the satellite base station device 10.

[0046] If it is determined that the execution conditions for executing CHO are satisfied (Yes in S502), the terminal device 20 proceeds to the process of S504 and performs handover to the satellite base station device 10 for which it has been determined that the execution conditions are satisfied. The process of S504 is the same as the connection process to the handover destination in the conventional CHO process, and therefore a description thereof will be omitted.

[0047] Fig. 5(B) shows an example of processing executed by the satellite base station device 10 according to this embodiment. The processing shown in Fig. 5(B) is realized by the processor of the satellite base station device 10 executing a program stored in memory. Note that the processing shown in Fig. 5(B) will be explained assuming that it is executed when the satellite base station device 10 connects to the terminal device 20.

[0048] At S551, the satellite base station device 10 identifies a satellite base station device 10 providing service in an adjacent cell area. Then, at S552, the satellite base station device 10 determines an execution condition for handover to the satellite base station device 10 providing service in the adjacent cell area. At S552, the execution condition for CHO may be acquired from the satellite base station device 10 providing service in the adjacent cell area. Alternatively, at S552, parameters such as the reference position or the distance from the reference position of the above-mentioned CondEvent D1 may be determined based on the location information of the cell area and the positions of the satellite base station device 10 and the handover candidate satellite base station device 10. Alternatively, parameters such as the time threshold of CondEvent T1 may be determined based on the location information of the cell area and the positions of the satellite base station device 10 and the handover candidate satellite base station device 10. The execution condition acquired at S552 includes two or more execution conditions and information instructing a logical operation on these execution conditions. Instead of the process of S552, the execution conditions for CHO may be acquired from a network node other than the satellite base station device 10 that provides service in the adjacent cell area.

[0049] Furthermore, in S552, the execution condition of CHO may be determined so that the terminal device 20 determines to execute handover when either a first execution condition of CHO determined by the satellite base station device 10 or a second execution condition of CHO acquired from the handover candidate satellite base station device 10 is satisfied. In this case, the execution condition may be determined so that the first execution condition and the second execution condition are determined by logical sum (OR). That is, in S552, the execution condition of CHO may be determined based on at least one of the execution condition acquired from the handover candidate satellite base station device 10 and the execution condition determined by the satellite base station device 10 to which the terminal device 20 is connected.

[0050] At S553, the satellite base station device 10 transmits, via an RRC Reconfiguration message to the terminal device 20, a CHO execution condition for handover to another satellite base station device 10. In the RRC Reconfiguration message, information identifying the other satellite base station device 10 and the execution condition for handover to the other satellite base station device 10, determined at S552, are transmitted in association with each other. In one example, the satellite base station device 10 may transmit a single RRC Reconfiguration message that associates information identifying the other satellite base station device 10 with the execution condition for handover to each other satellite base station device 10.

[0051] As described above, the satellite base station device 10 transmits to the terminal device 20 a pre-setting for CHO, which includes two or more execution conditions for executing handover and information indicating the logical operation of these execution conditions. The terminal device determines whether to execute handover according to the logical operation of the two or more execution conditions. This allows for flexible setting of the execution conditions for CHO.

[0052] <Other embodiments> The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention.

[0053] For example, in this embodiment, in order to use the existing IE format shown in FIG. 4A, an IE including two execution conditions and information indicating their logical operation, as shown in FIG. 4B, is used. However, a new IE including three or more execution conditions and information indicating their logical operation may be defined. For example, an executionCondList including N MeasIds and an OperatorList including N-1 logicOperators may be defined. In other words, the setting for notifying the format for notifying the preset setting is not limited to the format shown in FIG. 4B.

[0054] At least one of the satellite base station device 10 and the terminal device 20 according to the present invention can be realized by a program that causes a computer to operate as at least one of the satellite base station device 10 and the terminal device 20. These computer programs can be stored in a computer-readable storage medium or distributed via a network. [Explanation of symbols]

[0055] 1: wireless communication system, 10: satellite base station device, 20: terminal device, 30: earth station

Claims

1. A terminal device, a receiving means for receiving a pre-setting for handover from a currently connected base station device to another base station device, the pre-setting including a first condition, a second condition different from the first condition, and first information specifying a logical operation of the first and second conditions; a determination means for determining whether or not to execute a handover to the other base station device based on the preset setting; an execution means for executing a handover to the other base station device in accordance with a determination result of the determination means; A terminal device comprising:

2. The terminal device according to claim 1, characterized in that the pre-setting further includes a third condition different from the first and second conditions, and second information specifying a logical operation between the third condition and the logical operation result of the first and second conditions.

3. the first information is information specifying a logical sum, 2. The terminal device according to claim 1, wherein the determining means determines to execute a handover when the first condition or the second condition is satisfied.

4. the first condition is that a distance between the terminal device and a predetermined point included in a predetermined location range where the base station device provides service is greater than a threshold; 2. The terminal device according to claim 1, wherein the second condition is that the time that has elapsed since the terminal device connected to the base station device is greater than a threshold value.

5. 2. The terminal device according to claim 1, wherein the base station device is a satellite base station device.

6. A base station device, A base station device characterized by comprising a transmitting means for transmitting to a terminal device connected to the base station device a pre-setting for handover to another base station device, the pre-setting including a first condition for executing handover, a second condition different from the first condition, and information specifying a logical operation of the first and second conditions.

7. The base station device according to claim 6, further comprising a receiving means for receiving, from the other base station device, information specifying at least one of the first condition, a second condition different from the first condition, and information specifying a logical operation of the first and second conditions.

8. A wireless communication system including a terminal device and a base station device, The terminal device a receiving means for receiving a pre-setting for handover from the currently connected base station device to another base station device, the pre-setting including a first condition, a second condition different from the first condition, and first information specifying a logical operation of the first and second conditions; a determination means for determining whether or not to execute a handover to the other base station device based on the preset setting; an execution means for executing a handover to the other base station device in accordance with a determination result of the determination means; Equipped with The base station device a transmitting means for transmitting to a terminal device connected to the base station device a presetting for handover to another base station device, the presetting including a first condition for executing handover, a second condition different from the first condition, and information specifying a logical operation of the first and second conditions; A wireless communication system comprising:

9. A method for controlling a terminal device, comprising: receiving, from a currently connected base station device, a pre-configuration for handover to another base station device, the pre-configuration including a first condition, a second condition different from the first condition, and information specifying a logical operation of the first and second conditions; determining whether to execute a handover to the other base station device based on the preset setting; executing a handover to the other base station device according to a result of the determination; A control method comprising:

10. A method for controlling a base station device, comprising: A control method characterized by including transmitting to a terminal device connected to the base station device a pre-setting for handover to another base station device, the pre-setting including a first condition for executing the handover, a second condition different from the first condition, and information specifying a logical operation of the first and second conditions.

11. A control method for a wireless communication system including a terminal device and a base station device, The base station device transmits, to a terminal device connected to the base station device, a pre-setting for handover to another base station device, the pre-setting including a first condition for executing handover, a second condition different from the first condition, and information specifying a logical operation of the first and second conditions; The terminal device receives a pre-configuration for handover from the currently connected base station device to another base station device, the pre-configuration including a first condition, a second condition different from the first condition, and first information specifying a logical operation of the first and second conditions; determining whether or not to perform handover to the other base station device based on the preset setting; the terminal device executes handover to the other base station device according to a result of the determination; A control method comprising:

12. The terminal device computer a receiving step of receiving a pre-setting for a handover from a currently connected base station device to another base station device, the pre-setting including a first condition, a second condition different from the first condition, and information specifying a logical operation of the first and second conditions; a determination step of determining whether or not to execute handover to the other base station device based on the preset setting received in the receiving step; an execution step of executing a handover to the other base station device according to a result of the determination step; A program for causing a control method including:

13. The base station device computer A program that executes a control method that includes transmitting to a terminal device connected to the base station device a pre-setting for handover to another base station device, the pre-setting including a first condition for executing handover, a second condition different from the first condition, and information specifying a logical operation of the first and second conditions.

14. A computer in a wireless communication system including a terminal device and a base station device, a transmission step in which the base station device transmits, to a terminal device connected to the base station device, a pre-setting for handover to another base station device, the pre-setting including a first condition for executing handover, a second condition different from the first condition, and information specifying a logical operation of the first and second conditions; a receiving step in which the terminal device receives a pre-setting for handover from the currently connected base station device to another base station device, the pre-setting including a first condition, a second condition different from the first condition, and first information specifying a logical operation of the first and second conditions; a determination step of determining whether or not the terminal device should perform handover to the other base station device based on the preset setting; an execution step of the terminal device executing a handover to the other base station device according to a result of the determination step; A program for causing a control method including:

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