Target base station, source base station, radio communication system, target base station method, and computer program

Abstract

To provide a base station capable of restricting handover to a cell to which handover is not desirable.SOLUTION: In a radio communication system including a source base station that requests switching of communication with a user terminal from the source base station to another base station, and a target base station to which handover is requested, the target base station includes receiving means for receiving a handover request message from the source base station, and control means for performing control to restrict handover to a cell in question when the handover request message includes restriction information indicating a restriction on handover to the cell in question.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a target base station, a source base station, a wireless communication system, a method for a target base station, and a computer program, and relates to control of handover in a wireless base station. [Background technology]

[0002] There is a need for handover control according to the status of the user terminal. For example, Patent Document 1 discloses a technology for determining whether to perform a handover based on the traffic load of the source cell and the target cell. According to the technology disclosed in Patent Document 1, when a handover is caused by the traffic load of the cell, it is possible to prevent the terminal from returning to the original cell. However, when a handover is caused by a factor other than the traffic load of the cell, it is not possible to prevent the terminal from returning to the original cell. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2009-531896 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a target base station, a source base station, a wireless communication system, a method for the target base station, and a computer program that can solve the above-mentioned technical problems. As an example, an object of the present disclosure is to provide a target base station, a source base station, a wireless communication system, a method for the target base station, and a computer program that restrict handover to a cell where handover is not desired. [Means for solving the problem]

[0005] One aspect of the target base station includes a receiving means for receiving a handover request message from the source base station, and a control means for controlling to restrict handover to the relevant cell when the handover request message includes restriction information indicating a restriction on handover to the relevant cell.

[0006] One aspect of the source base station includes a generating means for generating a handover request message including restriction information indicating a restriction on handover to a cell including the cell of the source base station, and a transmitting means for transmitting the handover request message to a target base station.

[0007] One aspect of the wireless communication system includes a source base station having a generating means for generating a handover request message including restriction information indicating a restriction on handover to a corresponding cell including the cell of the source base station, and a transmitting means for transmitting the handover request message to a target base station; a target base station having a receiving means for receiving the handover request message from the source base station, and a control means for controlling to restrict handover to the corresponding cell when the handover request message includes restriction information indicating a restriction on handover to the corresponding cell.

[0008] One aspect of the method of the target base station is to receive a handover request message from the source base station, and if the handover request message includes restriction information indicating a restriction on handover to a corresponding cell, to control the handover to the corresponding cell to be restricted.

[0009] One aspect of the computer program causes a computer to execute a method of a target base station that receives a handover request message from a source base station and, if the handover request message includes restriction information indicating a restriction on handover to a corresponding cell, controls the target base station to restrict handover to the corresponding cell. [Effects of the Invention]

[0010] According to each aspect of the above-mentioned target base station, source base station, wireless communication system, target base station method, and computer program, it is possible to restrict handover to a cell to which handover is not desirable. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a block diagram illustrating an example of the configuration of a target base station according to the present disclosure. [Figure 2] FIG. 1 illustrates an example of a target base station method according to this disclosure. [Figure 3] 1 is a block diagram illustrating an example of a configuration of a wireless communication system according to the present disclosure. [Figure 4] FIG. 2 is a block diagram illustrating an example of the configuration of a source base station according to the present disclosure. [Figure 5] FIG. 1 illustrates an example of a source base station method according to this disclosure. [Figure 6] FIG. 1 illustrates an example of a target base station method according to this disclosure. [Figure 7] 1 illustrates an example method for a wireless communication system according to the present disclosure. [Figure 8] 1 illustrates an example method for a wireless communication system according to the present disclosure. [Figure 9] FIG. 2 is a block diagram illustrating an example of the configuration of a target base station according to the present disclosure. [Figure 10] FIG. 1 illustrates an example of a target base station method according to this disclosure. [Figure 11] FIG. 2 is a block diagram illustrating an example of the configuration of a source base station according to the present disclosure. [Figure 12] FIG. 2 is a block diagram illustrating an example of the configuration of a target base station according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of a target base station, a source base station, a wireless communication system, a method of the target base station, and a computer program will be described with reference to the drawings. [1: First embodiment]

[0013] A first embodiment of a target base station, a source base station, a wireless communication system, a method of the target base station, and a computer program will be described below. The first embodiment of a target base station, a source base station, a wireless communication system, a method of the target base station, and a computer program will be described below using a target base station 20 according to this disclosure.

[0014] Fig. 1 is a block diagram showing the configuration of a target base station 20 according to this disclosure. As shown in Fig. 1, the target base station 20 includes a receiving unit 211 and a control unit 212. The operation of the target base station 20 will be described with reference to Fig. 2.

[0015] As shown in FIG. 2, the receiving unit 211 receives a handover request message from a source base station (step S1). When the handover request message includes restriction information indicating a restriction on handover to the corresponding cell, the control unit 212 performs control to restrict handover to the corresponding cell (step S2). The corresponding cell may be a cell that requires a restriction on handover for a specific user terminal. The specific user terminal may be a user terminal that is communicating with the source base station that transmits the handover request message. The corresponding cell may include the cell of the source base station. The corresponding cell may be multiple cells. The corresponding cell may be multiple cells including the cell of the source base station. [Technical Effects]

[0016] The target base station 20 according to this disclosure restricts handover to the handover source cell after handover, thereby restricting undesired handover. The target base station 20 performs control according to information included in the message, so that undesired handover can be restricted without the target base station 20 itself having to perform processing to determine whether to restrict handover. [2: Second embodiment]

[0017] A second embodiment of a target base station, a source base station, a wireless communication system, a method of the target base station, and a computer program will be described below. Hereinafter, a second embodiment of a target base station, a source base station, a wireless communication system, a method of the target base station, and a computer program will be described using a wireless communication system S according to this disclosure. [2-1: Example of the configuration of wireless communication system S]

[0018] FIG. 3 illustrates a configuration of a wireless communication system to which this embodiment is applied. FIG. 3 illustrates a situation in which a user terminal 500 is communicating with a wireless base station 10 in a cell C1 via wireless communication. The user terminal 500 may be a communication terminal mounted on a mobile object. The cell C1 is a cell managed by the wireless base station 10. A base station that is communicating with the user terminal and requests switching of communication with the user terminal from its own station to another base station is referred to as a "source base station." Requesting switching of communication with the user terminal from its own station to another base station is referred to as "requesting handover." The wireless base station 10 in this embodiment is an example of a base station that requests handover, and is therefore referred to as a "source base station 10." Furthermore, the cell C1 is referred to as a source cell C1. Furthermore, a request from a base station that is communicating with the user terminal to communicate with the user terminal is referred to as "requesting handover."

[0019] The source base station 10 is connected to a core network (CN) device 1000 and a radio base station 20, and communicates with the CN device 1000 and the target base station 20. A base station to which handover is requested is referred to as a "target base station." The radio base station 20 in this embodiment is an example of a base station to which handover is requested, and is therefore referred to as a "target base station 20." In addition, a cell managed by the target base station 20 is referred to as a target cell C2.

[0020] 3 illustrates an example in which the range of the source cell C1 includes the range of the target cell C2, but in this embodiment, the range of the target cell C2 may include the range of the source cell C1. Also, the range of the source cell C1 and the range of the target cell C2 may partially overlap. Also, the range of the source cell C1 and the range of the target cell C2 may not overlap. [2-2: Source base station 10]

[0021] Fig. 4 is a block diagram showing the configuration of a source base station 10 according to this disclosure. As shown in Fig. 4, the source base station 10 includes a generation unit 111 and a transmission unit 112. The operation of the source base station 10 will be described with reference to Fig. 5. A case will be described in which the source base station 10 controls handover of a connected user terminal 500 to another cell.

[0022] As shown in Fig. 5, when handover is necessary for the user terminal 500 (step S11: Yes), the generation unit 111 determines whether or not restriction of handover to the corresponding cell is necessary (step S12). Restriction of handover to the corresponding cell is necessary when it is undesirable to be handed over (returned) to the corresponding cell again after handover. Depending on the purpose of the handover or the state of the user terminal 500 at the time of handover, it may not be desirable to be returned to the corresponding cell again after handover. The corresponding cell may include a cell managed by the source base station 10 (i.e., source cell C1).

[0023] For example, when the user terminal 500 is moving at high speed, the source base station 10 performs a handover because the user terminal 500 has moved away from the source cell C1. For this reason, it is undesirable for the user terminal 500 to be returned to the source cell C1 again. For example, when the user terminal 500 is moving at high speed, moving the user terminal 500 from a cell with a relatively narrow range to a cell with a relatively wide range can reduce the number of handover controls required. Also, when the user terminal 500 is attempting to use a specific service, the source base station 10 performs a handover because the source cell C1 is not covered by the specific service. In this case, it is undesirable for the user terminal 500 to be returned to the source cell C1 again, at least while the user terminal 500 is using the specific service.

[0024] If a restriction on handover to the corresponding cell is necessary (step S12: Yes), the generation unit 111 generates a handover request (HANDOVER REQUEST) message including restriction information indicating a restriction on handover to the corresponding cell (step S13). The restriction information includes a restriction period for restricting handover to the corresponding cell. The generation unit 111 may include, as control information, a parameter indicating a restriction period for restricting handover to the current cell in the handover request message. The current cell may be a cell with which the user terminal 500 is currently communicating. In other words, the current cell at the time of generating the handover request message may be the source cell C1 managed by the source base station 10. Note that a cell that is the current cell at the time of generating the handover request message may be referred to as a "handover source cell." The "handover source cell" may be a cell with which the user terminal 500 was communicating at the time of generating the handover request message. The current cell after execution of handover based on the handover request message may be a cell different from the "handover source cell." Furthermore, a parameter indicating a restriction period for restricting handover to the current cell may be referred to as a "restriction parameter." The generation unit 111 may be able to set a parameter indicating infinity as the restriction parameter. There is no limitation on how to determine the restriction parameter that can be set.

[0025] If there is no need to restrict handover to the cell (step S12: No), the generation unit 111 generates a handover request message that does not include control information (step S14). In this way, the setting of the restriction parameters described above can be omitted. The transmission unit 112 transmits the generated handover request message to the target base station 20 (step S15). [2-3: Target base station 20]

[0026] The operation of the target base station 20 will be described with reference to Fig. 6. As shown in Fig. 6, when the receiver 211 receives a handover request message from the source base station 10 (step S21: Yes), the target base station 20 hands over the user terminal 500. The controller 212 determines whether the handover request message includes restriction information indicating a restriction on handover to the cell in question (step S22). The case where the restriction information indicating a restriction on handover is included means that it is not desired for the user terminal 500 to be returned to the source cell for at least a certain period of time after the handover.

[0027] If the handover request message includes restriction information indicating a restriction on handover to the corresponding cell (step S22: Yes), the control unit 212 performs control to restrict handover to the corresponding cell (step S23). The corresponding cell includes the cell of the source base station 10 that transmitted the handover request message. The control unit 212 holds the information, included in the handover request message, indicating a restriction period for restricting handover to the handover source cell of the handover source for at least the restriction period.

[0028] The control unit 212 controls so as to restrict handover to the cell until the restriction period has elapsed since the user terminal 500 was handed over. In other words, if the above-mentioned mobility restriction parameter is set to valid, the control unit 212 does not control handover to the cell of the source base station 10 for the specified restriction period after the handover is completed.

[0029] The control unit 212 may acquire information about the handover source cell from the handover request message. For example, the control unit 212 may acquire information about the handover source cell from "UE History Information" information defined as a required parameter in the 3GPP (registered trademark) standard specifications (3GPP TS36.423 / 38.423).

[0030] If the handover request message does not include restriction information (step S22: No), handover control is performed in which the cell handover restriction of this embodiment is not applied. That is, after handover, there is a possibility that the mobile station may be handed over to (return to) the corresponding cell again. [2-4: Example of operation of wireless communication system S]

[0031] An example of the operation of the wireless communication system S will be described with reference to Fig. 7. Fig. 7 illustrates a case where the source base station 10 controls handover of the connected user terminal 500 to the target cell C2. It also illustrates a case where it is not desired for the user terminal 500 to be returned to the handover source cell for at least a certain period of time after the handover.

[0032] When performing handover control to the target cell C2 for the connected user terminal 500, the generation unit 111 includes a mobility restriction parameter in a handover request message to the target base station 20 (step S13). The transmission unit 112 transmits the generated handover request message to the target base station 20 (step S15).

[0033] The receiver 211 receives a handover request message from the source base station 10 (step S1). If a mobility restriction parameter related to the handover source cell is set in the handover request message, the controller 212 does not control handover to the handover source cell until a specified restriction period has elapsed after the handover of the user terminal 500 is completed (step S23).

[0034] In the handover control of this embodiment, during the limited period, the handover source cell may not be included in the target of the cell quality measurement report instruction (Measurement Configuration) for subsequent handover control to the user terminal 500, or the handover source cell may be included in the target of the cell quality measurement report instruction but no handover instruction to the handover source cell may be issued.

[0035] Note that the radio base station is called eNB in ​​4G (LTE) and gNB in ​​5G (NR). The CN device is called EPC in 4G (LTE) and 5GC in 5G (NR). Although the description is based on the 3GPP standard specifications of 4G (LTE) and 5G (NR), there are no particular limitations on the application of this embodiment, and the application of this embodiment is not limited to only 4G and 5G. [Technical Effects]

[0036] For example, Comparative Example 1 described in the above-mentioned Patent Document 1 determines whether to perform a handover based on the traffic loads of the source cell and the target cell, and restricts the handover. Comparative Example 1 can prevent a return to the original cell when a handover is caused by a traffic load factor of a cell, but cannot restrict a return to the original cell in a situation where the traffic load is not relevant. In other words, Comparative Example 1 cannot restrict a handover to the handover source cell after a handover caused by a situation other than the radio quality situation of the user terminal is performed.

[0037] Also, there is Comparative Example 2, in which handover history information is notified to the handover destination base station at the time of handover, thereby avoiding ping-pong handover. Ping-pong handover refers to repeated undesirable handovers between a source base station and a target base station. Comparative Example 2 can restrict the return to the original cell when there is a history of frequent ping-pong handovers, but cannot restrict the return to the original cell when there is no history of frequent ping-pong handovers. In other words, Comparative Example 2 also cannot restrict handover to the handover source cell after a handover due to a condition other than the radio quality condition of the user terminal is performed.

[0038] In contrast, the wireless communication system S according to this disclosure can control handover depending on conditions other than the wireless quality condition of the user terminal. When the source base station 10 hands over the terminal to a cell of another base station, the user terminal 500 can use the cell of the other base station for at least a certain period of time without being handed over to the original cell.

[0039] In the above-described Comparative Examples 1 and 2, the target base station determines whether to restrict handover to the handover source cell. In contrast, the source base station 10 according to this disclosure requests handover and also specifies that the target base station 20 restricts handover to the source cell C1, and the target base station 20 follows the specification of the source base station 10. Therefore, the target base station 20 does not need to perform processing to determine whether to restrict handover by itself. [3: Third embodiment]

[0040] A third embodiment of a target base station, a source base station, a wireless communication system, a method of the target base station, and a computer program will be described below. Hereinafter, a third embodiment of a target base station, a source base station, a wireless communication system, a method of the target base station, and a computer program will be described using a wireless communication system S according to this disclosure.

[0041] While the second embodiment is a form in which handover is performed based on an interface between radio base stations, the third embodiment is a form in which handover is performed based on an interface between radio base stations and CN devices. The source base station 10 may transmit a handover request message to the target base station 20 via the CN device 1000. Furthermore, the target base station 20 may receive the handover request message from the source base station 10 via the CN device 1000. The third embodiment may be the same as the second embodiment except that the source base station 10 and the target base station 20 communicate via the CN device 1000.

[0042] Furthermore, in the third embodiment, the CN device to which the source base station 10 is connected may be different from the CN device to which the target base station 20 is connected. When the source base station 10 and the target base station 20 are connected to different CN devices, communication between the different CN devices is possible. [Example of operation]

[0043] An example of the operation of the wireless communication system S will be described with reference to Fig. 8. A case will be described in which the source base station 10 controls handover of the connected user terminal 500 to the target cell C2. Also, a case will be described in which it is not desired to return to the source cell for at least a certain period of time after handover.

[0044] The generation unit 111 generates a handover request message to the CN device 1000 (step S213). The generation unit 111 includes, in the handover request message to the CN device 1000, information indicating a restriction period for restricting handover to the mobility restriction parameter handover source cell. In the 3GPP standard specifications, there is "Source to Target Transparent Container" information that is set transparently to the CN device and transferred directly to the target device (3GPP TS36.413 / 38.413). By setting information indicating a restriction period for the mobility restriction parameter handover source cell in this information, the CN device does not need to perform additional control on the setting of the above mobility restriction parameter. The transmission unit 112 transmits the handover request message (step S215).

[0045] The CN device 1000 notifies the target base station 20 of a handover request message including a "restriction period for restricting handover to the handover source cell" (step S220).

[0046] The receiver 211 receives the handover request message (step S221). If a restriction period for restricting handover to the handover source cell is set in the handover request message, the controller 212 does not control handover to the handover source cell until the specified restriction period has elapsed after the handover of the user terminal 500 is completed (step S223).

[0047] The control unit 212 may acquire information about the handover source cell from the handover request message. For example, the control unit 212 may acquire information about the handover source cell from "UE History Information" information defined as a required parameter in the 3GPP standard specifications (3GPP TS36.413 / 38.413). [4: Fourth embodiment]

[0048] A fourth embodiment of a target base station, a source base station, a wireless communication system, a method of the target base station, and a computer program will be described below. Hereinafter, a fourth embodiment of a target base station, a source base station, a wireless communication system, a method of the target base station, and a computer program will be described using a wireless communication system S according to this disclosure. In the third embodiment, multiple cells may be designated as targets for restricting handover. [Example of operation]

[0049] An example of operation of the wireless communication system S according to the third embodiment will be described with reference to Fig. 7. The source base station 10 controls handover to the target cell C2 for the connected user terminal 500. At this time, a case will be described in which handover to the designated cell is not desired for at least a certain period after the handover.

[0050] When performing handover control to the target cell C2 for the currently connected user terminal 500, the generation unit 111 includes, in a handover request message to the target base station 20, information about a designated cell for which handover is to be restricted, in addition to the mobility restriction parameters (step S13). The information about the designated cell may be a cell ID that can identify the designated cell. A plurality of cells for which handover is to be restricted may be set as designated cells. For example, a plurality of cell IDs may be included in the handover request message. Furthermore, the generation unit 111 may include, in the handover request message to the target base station 20, each of the restriction parameters corresponding to a plurality of cells.

[0051] For example, when requesting handover of user terminal 500 moving at high speed, generation unit 111 may set a cell covering the same geographical area as source cell C1 as the designated cell. Furthermore, when a handover request is triggered by user terminal 500 starting to use a specific service, generation unit 111 may set a cell that is not covered by the specific service and covers the same geographical area as source cell C1 as the designated cell. In other words, generation unit 111 may generate a handover request message including restriction information that indicates a restriction on handover to cells included in a predetermined area around source cell C1 and the cell of source base station 10. Note that the above example is an example of setting multiple cells, and setting multiple cells is not limited to these cases.

[0052] The transmitter 112 transmits the generated handover request message to the target base station 20 (step S15). The receiver 211 receives the handover request message from the source base station 10 (step S1). If a mobility restriction parameter for the designated cell is set in the handover request message, the controller 212 does not control handover to the designated cell until a designated restriction period has elapsed after the handover of the user terminal 500 is completed (step S23).

[0053] In the third embodiment, handover based on an interface between CN devices may be performed in the same manner as in the second embodiment. [5: Fifth embodiment]

[0054] A fifth embodiment of a target base station, a source base station, a wireless communication system, a method of the target base station, and a computer program will be described below. Hereinafter, a fifth embodiment of a target base station, a source base station, a wireless communication system, a method of the target base station, and a computer program will be described using a wireless communication system S according to this disclosure. In the fifth embodiment, when the target base station performs a handover, restriction information may be handed over to the base station of the handover destination. [Target base station 20 in the fifth embodiment]

[0055] Fig. 9 is a block diagram showing the configuration of a target base station 20 according to the fifth embodiment. As shown in Fig. 9, the target base station 20 may include a generation unit 213 and a transmission unit 214 in addition to a reception unit 211 and a control unit 212. The operations of the generation unit 213 and the transmission unit 214 will be described with reference to Fig. 10.

[0056] 10, when a handover is required for the user terminal 500 (step S41: Yes), the generation unit 213 determines whether or not a limit period is set for the user terminal 500 that requires a handover (step S42). When a limit period is not set for the user terminal 500 that requires a handover (step S42: No), the process proceeds to step S45.

[0057] If a restriction period has been set for the user terminal 500 requiring handover (step S42: Yes), the generation unit 213 determines whether the current time is within the restriction period (step S43). If the current time is within the restriction period (step S43: Yes), the generation unit 213 generates a handover request message including restriction information (step S44). That is, the target base station 20 may decide to perform handover control to a cell under the control of another base station that is not subject to restriction before the restriction period specified for the user terminal 500 elapses. In this case, the restriction information may include information indicating a cell corresponding to the restriction set for the user terminal 500 (for example, a cell including the handover source cell) and information indicating a new restriction period. The new restriction period may be a period obtained by subtracting the time that has already elapsed from the period specified in the handover request message received from the source base station 10. In this way, the target base station 20 may hand over information to the next handover destination base station according to an operation policy or the like.

[0058] If the current time is outside the restriction period (if the restriction period has already passed) (step S43: No), the generation unit 213 generates a handover request message that does not include control information (step S45). In other words, the setting of the above-mentioned mobility restriction parameters is omitted. The transmission unit 214 transmits the generated handover request message to another base station (step S46).

[0059] In this way, when a handover is requested during the restriction period, the generation unit 213 may generate a handover request message including restriction information indicating a restriction on handover to the relevant cell, and the transmission unit 214 may transmit the handover request message generated by the generation unit 213 to the next handover destination base station. This makes it possible to restrict handover of the user terminal 500 to the relevant cells, including the source cell C1, during the restriction period specified by the source base station 10.

[0060] The corresponding cells including the source cell C1 may include a plurality of cells. The corresponding cells in the fifth embodiment may be the designated cells in the fourth embodiment. [6: Sixth embodiment]

[0061] As shown in FIG. 11, the source base station 10 according to this disclosure may include an information processing device 1001 and a storage device 1002.

[0062] The information processing device 1001 may include at least one of a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and an FPGA (Field Programmable Gate Array). The information processing device 1001 may load a computer program. For example, the information processing device 1001 may load a computer program stored in the storage device 1002. For example, the information processing device 1001 may load a computer program stored in a computer-readable recording medium using a recording medium reading device (not shown). The information processing device 1001 may acquire (i.e., download or load) the computer program from a device (not shown) located outside the source base station 10 via a communication device (not shown). The information processing device 1001 executes the loaded computer program. As a result, logical functional blocks for executing a method to be performed by the source base station 10 are realized within the information processing device 1001. Specifically, logical functional blocks for executing the above-described method are realized within the information processing device 1001. That is, the information processing device 1001 can function as a controller for realizing logical functional blocks for executing the operations that the source base station 10 should perform.

[0063] The storage device 1002 can store desired data. For example, the storage device 1002 may temporarily store a computer program executed by the information processing device 1001. The storage device 1002 may temporarily store data that the information processing device 1001 temporarily uses when the information processing device 1001 is executing a computer program. The storage device 1002 may store data that the source base station 10 stores for a long period of time. The storage device 1002 may include at least one of a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk device, a magneto-optical disk device, an SSD (Solid State Drive), and a disk array device.

[0064] As shown in FIG. 12, the target base station 20 according to this disclosure may include an information processing device 2001 and a storage device 2002.

[0065] The information processing device 2001 may include at least one of a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and an FPGA (Field Programmable Gate Array). The information processing device 2001 may load a computer program. For example, the information processing device 2001 may load a computer program stored in the storage device 2002. For example, the information processing device 2001 may load a computer program stored in a computer-readable storage medium using a storage medium reading device (not shown). The information processing device 2001 may acquire (i.e., download or load) the computer program from a device (not shown) located outside the target base station 20 via a communication device (not shown). The information processing device 2001 executes the loaded computer program. As a result, logical functional blocks for executing a method to be performed by the target base station 20 are realized within the information processing device 2001. Specifically, logical functional blocks for executing the above-described method are realized within the information processing device 2001. In other words, the information processing device 2001 can function as a controller for realizing logical functional blocks for executing the operations that the target base station 20 should perform.

[0066] The storage device 2002 can store desired data. For example, the storage device 2002 may temporarily store a computer program executed by the information processing device 2001. The storage device 2002 may temporarily store data that the information processing device 2001 temporarily uses when the information processing device 2001 is executing a computer program. The storage device 2002 may store data that the target base station 20 stores long-term. The storage device 2002 may include at least one of a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk device, a magneto-optical disk device, an SSD (Solid State Drive), and a disk array device. [7: Note]

[0067] The following additional notes are provided regarding the above-described embodiment. [Appendix 1] receiving means for receiving a handover request message from a source base station; a control means for controlling the handover to be restricted when the handover request message includes restriction information indicating a restriction on the handover to the corresponding cell; A target base station comprising: [Appendix 2] The restriction information includes a restriction period for restricting handover to the corresponding cell, The control means controls so as to restrict handover to the relevant cell during the restriction period. 1. A target base station as defined in claim 1. [Appendix 3] The corresponding cell includes the cell of the source base station that transmitted the handover request message. 3. A target base station according to claim 1 or 2. [Appendix 4] a generating unit for generating a handover request message including restriction information indicating a restriction on handover to the corresponding cell when a handover is requested during the restriction period; 2. A target base station as defined in Supplementary Note 2. [Appendix 5] a generating means for generating a handover request message including restriction information indicating a restriction on handover to a corresponding cell including a cell of the source base station; a transmitting means for transmitting the handover request message to a target base station; A source base station comprising: [Appendix 6] The generating means generates the handover request message including the restriction information indicating a restriction on handover to a cell of the source base station and a cell included in a predetermined area around the cell of the source base station. 6. The source base station according to claim 5. [Appendix 7] a source base station including: a generating means for generating a handover request message including restriction information indicating a restriction on handover to a corresponding cell including a cell of the source base station; and a transmitting means for transmitting the handover request message to a target base station; a target base station including: a receiving means for receiving the handover request message from the source base station; and a control means for controlling to restrict handover to the corresponding cell when the handover request message includes restriction information indicating a restriction on handover to the corresponding cell; A wireless communication system comprising: [Appendix 8] the source base station sends the handover request message to the target base station via a core network device; The target base station receives the handover request message from the source base station via a core network device. 8. The wireless communication system of claim 7. [Appendix 9] receiving a handover request message from a source base station; If the handover request message includes restriction information indicating a restriction on handover to a corresponding cell, control is performed to restrict handover to the corresponding cell. Target base station method. [Appendix 10] receiving a handover request message from a source base station; If the handover request message includes restriction information indicating a restriction on handover to a corresponding cell, control is performed to restrict handover to the corresponding cell. A computer program product that causes a computer to carry out the target base station method.

[0068] The present invention can be modified as appropriate within the scope that does not contradict the gist or idea of ​​the invention that can be read from the claims and the entire specification, and the target base station, source base station, wireless communication system, target base station method, and computer program that involve such modifications are also included in the technical idea of ​​the present invention. [Explanation of symbols]

[0069] 10 Source base station 111 Generation part 112 Transmitter 20 Target Base Station 211 Receiving unit 212 Control Unit 213 Generation part 214 Transmitter S Wireless Communication System 1000 CN equipment 500 user terminals C1 source cell C2 target cell

Claims

1. receiving means for receiving a handover request message from a source base station; a control means for controlling the handover to be restricted when the handover request message includes restriction information indicating a restriction on the handover to the corresponding cell; A target base station comprising:

2. The restriction information includes a restriction period for restricting handover to the corresponding cell, The control means controls so as to restrict handover to the relevant cell during the restriction period. The target base station of claim 1 .

3. The corresponding cell includes the cell of the source base station that transmitted the handover request message. A target base station according to claim 1 or 2.

4. a generating unit for generating a handover request message including restriction information indicating a restriction on handover to the corresponding cell when a handover is requested during the restriction period; The target base station of claim 2 .

5. a generating means for generating a handover request message including restriction information indicating a restriction on handover to a corresponding cell including a cell of the source base station; a transmitting means for transmitting the handover request message to a target base station; A source base station comprising:

6. The generating means generates the handover request message including the restriction information indicating a restriction on handover to a cell of the source base station and a cell included in a predetermined area around the cell of the source base station. The source base station according to claim 5 .

7. a source base station including: a generating means for generating a handover request message including restriction information indicating a restriction on handover to a corresponding cell including a cell of the source base station; and a transmitting means for transmitting the handover request message to a target base station; a target base station including: a receiving means for receiving the handover request message from the source base station; and a control means for controlling to restrict handover to the corresponding cell when the handover request message includes restriction information indicating a restriction on handover to the corresponding cell; A wireless communication system comprising:

8. the source base station sends the handover request message to the target base station via a core network device; The target base station receives the handover request message from the source base station via a core network device.

8. The wireless communication system according to claim 7.

9. receiving a handover request message from a source base station; If the handover request message includes restriction information indicating a restriction on handover to a corresponding cell, control is performed to restrict handover to the corresponding cell. Target base station method.

10. receiving a handover request message from a source base station; If the handover request message includes restriction information indicating a restriction on handover to a corresponding cell, control is performed to restrict handover to the corresponding cell. A computer program product that causes a computer to carry out the target base station method.

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