WO2022049899A1

WO2022049899A1 - Terminal device, and base station device

Info

Publication number: WO2022049899A1
Application number: PCT/JP2021/026213
Authority: WO
Inventors: 誠山本; 秀章新明; 重人鈴木; 賢一飯島; 耕一金森
Original assignee: シャープ株式会社
Priority date: 2020-09-07
Filing date: 2021-07-13
Publication date: 2022-03-10
Also published as: JP2023159474A

Abstract

Provided are a terminal device and a base station device with which it is possible to perform handover with an appropriate timing. A terminal device (10) is provided with: a measuring unit for measuring a signal strength of a signal from a first base station device (20A); a transmitting unit for transmitting the measurement result to the first base station device; a receiving unit for receiving a handover instruction from the first base station device; and a handover executing unit for executing handover to a second base station device (20B) in accordance with the handover instruction from the first base station device. The first base station device sets a first threshold (W1) for performing the handover, and a second threshold (W2) smaller than the first threshold, and generates the handover instruction corresponding to a relationship between the measurement result and the first and second thresholds.

Description

Terminal equipment and base station equipment

The present invention relates to a terminal device and a base station device that perform wireless communication. This application claims priority based on Japanese Patent Application No. 2020-14991 filed in Japan on September 7, 2020, the contents of which are incorporated herein by reference.

In a wireless mobile communication system, as a terminal device moves, it moves away from the coverage of the base station device (also referred to as “source base station”) of the source and becomes the coverage of an adjacent base station device (also referred to as “target base station”). In the case of entering, in order to move while continuing communication without reconnecting, it is necessary to perform a handover from the base station device of the moving source to the adjacent base station device. In order to perform handover to an appropriate base station device, the terminal device uses the signal strength of the reference signal from the source base station device or the target base station device (RSRP (reference signal received power), RSRQ (reference signal received quality), etc.). And report the result of the measurement to the base station equipment of the moving source. The base station device of the migration source determines whether or not to execute the handover based on the measurement result reported from the terminal device. If it is determined to execute the handover, the source base station apparatus transmits a handover request to the target base station apparatus and a handover command is transmitted to the terminal apparatus. Alternatively, the terminal device determines whether or not to autonomously execute the handover based on the measurement result, and executes the handover. Various techniques for a mobile terminal device to perform a handover at an appropriate timing are disclosed.

Special Table 2017-511623 (published April 20, 2017)

However, if the terminal device performs a handover during communication with the base station device, for example, a momentary interruption or the like may occur. For this reason, if large-capacity communication such as eMBB (enhanced mobile broadband) is in progress, the time required to complete data download will increase, or if high-reliability communication such as URLLC (ultra-reliable and low latency communications) is in progress. Symptoms such as the need to resend important data may be noticeable.

In view of the above circumstances, one aspect of the present invention is to provide a technique that allows a terminal device to execute a handover at an appropriate timing without hindering processing such as data download or upload.

In order to solve the above problems, the terminal device according to one aspect of the present invention is a terminal device that performs wireless communication, and includes a measuring unit that measures the signal strength of a signal received from the first base station device. A transmission unit that transmits the measurement result of the signal strength to the first base station apparatus, a reception unit that receives a handover command from the first base station apparatus based on the measurement result, and the first base station. The first base station apparatus includes a handover execution unit that executes a handover process to the second base station apparatus according to a handover command from the apparatus, and the first base station apparatus has a first threshold value for performing the handover process. A second threshold value smaller than the first threshold value is set, and a handover command is generated according to the relationship between the signal strength of the measurement result and the first threshold value and the second threshold value.

In order to solve the above problems, the terminal device according to one aspect of the present invention is a terminal device that performs wireless communication, and includes a measuring unit that measures the signal strength of a signal received from a second base station device. A transmission unit that transmits the measurement result of the signal strength to the first base station apparatus, a reception unit that receives a handover command from the first base station apparatus based on the measurement result, and the first base station apparatus. The first base station apparatus includes an execution unit that executes a handover process to the second base station apparatus according to a handover command from the above, and the first base station apparatus has a third threshold value for performing the handover process and the said. A fourth threshold value larger than the third threshold value is set, and a handover command is generated according to the relationship between the signal strength of the measurement result and the third threshold value and the fourth threshold value.

In order to solve the above problems, the terminal device according to one aspect of the present invention is a terminal device that performs wireless communication, and includes a measuring unit that measures the signal strength of a signal received from the first base station device. A terminal device including an execution unit that executes a handover process from the first base station device to the second base station device based on the measurement result, and performs the handover process in the handover process. A first threshold value for the purpose and a second threshold value smaller than the first threshold value are set, and the relationship between the signal strength of the measurement result and the first threshold value and the second threshold value is set. Execute the handover process.

In order to solve the above problems, the terminal device according to one aspect of the present invention is a terminal device that performs wireless communication, and includes a measuring unit that measures the signal strength of the signal received from the second base station device. A terminal device including an execution unit that executes a handover process from the first base station device to the second base station device based on the measurement result, and performs the handover process in the handover process. A third threshold value for the purpose and a fourth threshold value larger than the third threshold value were set, and the relationship between the signal strength of the measurement result and the third threshold value and the fourth threshold value was set. Execute the handover process.

In order to solve the above problems, the base station apparatus according to one aspect of the present invention is a base station apparatus that performs wireless communication, and is a measurement result of a signal strength of a signal received from the base station apparatus in the terminal apparatus. The control unit includes a reception unit that receives the signal strength, and a control unit that generates a handover command for the terminal device based on the measurement result of the signal strength. , A second threshold value smaller than the first threshold value is set, and a handover command is generated according to the relationship between the signal strength of the measurement result and the first threshold value and the second threshold value.

In order to solve the above problems, the base station device according to one aspect of the present invention is a base station device that performs wireless communication, and the signal strength of the signal received from the terminal device to the second base station device is high. A receiving unit that receives the measurement result, a control unit that generates a handover command for the terminal device based on the measurement result of the signal strength, and a transmitting unit that transmits the generated handover command to the terminal device. The control unit sets a third threshold value for performing the handover process and a fourth threshold value larger than the third threshold value, and sets the signal strength of the measurement result, the third threshold value, and the third threshold value. A handover command is generated according to the relationship with the fourth threshold value.

According to one aspect of the present invention, the terminal device can execute the handover at an appropriate timing without disturbing the processing such as data download or upload.

It is an overall view which shows the structure of the wireless communication system which includes the terminal apparatus and the base station apparatus which concerns on embodiment of this invention. It is a block diagram which shows an example of the configuration of the terminal apparatus and the base station apparatus which constitute the wireless communication system shown in FIG. 1. It is a conceptual diagram for demonstrating the outline of the handover processing in Embodiment 1 of this invention. It is a sequence diagram which shows an example of the flow of the handover processing in Embodiment 1 of this invention. It is a conceptual diagram for demonstrating the outline of the handover processing in Embodiment 2 of this invention. It is a sequence diagram which shows an example of the flow of the over processing in Embodiment 2 of this invention. It is a conceptual diagram for demonstrating the outline of the handover processing in Embodiment 3 of this invention. It is a block diagram which shows the structure of the terminal apparatus in Embodiment 4 of this invention.

[Embodiment 1] Hereinafter, one embodiment of the present invention will be described in detail.

<System configuration>
FIG. 1 is an overall view showing an example of the configuration of a wireless communication system 100 including a terminal device 10 and a base station device 20 according to an embodiment of the present invention. First, the overall configuration of the wireless communication system 100 will be described with reference to FIG.

The wireless communication system 100 is a communication system that provides a mobile communication service. The wireless communication system 100 includes a plurality of

base station devices

20A, 20B, 20C, ... (Hereinafter, also collectively referred to as "base station device 20"). The coverage X, Y, Z ... Of each base station device 20 includes a plurality of

terminal devices

10A, 10B, 10C ... (hereinafter, collectively referred to as "terminal device 10"), and each of them. Wireless communication is performed with the base station device 20. Examples of the terminal device 10 include a smartphone, a tablet terminal, a personal computer, and the like.

The wireless communication system 100 also includes a core network 30 that connects each base station device 20 to an external IP network (Internet, fixed telephone network, etc.) 40 or the like. The core network 30 may be, for example, a core network that communicates by a communication method according to a 4G standard. However, the core network of one aspect of the present invention is not limited to this, and the core network 30 may be a core network that supports the 5G standard, or may be a core network that supports the 3G standard. May be good. A core network that supports the 4G standard is also called an EPC (evolved packet core). Further, the base station device 20 that provides wireless communication to the terminal device 10 is also referred to as a RAN (radio access network).

The core network 30 connects the base station devices 20 to each other, and each base station device 20 and the external IP network 40, and the user of the terminal device 10 is authenticated, called, or connected to the external IP network. We provide various services such as.

The terminal device 10 is a mobile body and moves in the wireless communication system 100, for example, from the coverage X of the base station device 20A to the coverage Y of the adjacent base station device 20B. At this time, the terminal device 10 can execute the handover to switch the communication partner from the base station device 20A to the base station device 20B and continue the wireless communication.

FIG. 2 is a block diagram showing an example of the configuration of each base station device 20 and each terminal device 10 constituting the wireless communication system 100. Hereinafter, the configurations of the base station device 20 and the terminal device 10 will be described with reference to FIG. 2. However, illustration and description will be omitted for configurations not related to this embodiment. Further, although the configuration of each base station device 20 constituting the wireless communication system 100 may be various, the configuration common to each base station device 20 will be described below by taking the base station device 20A as an example. Similarly, the configuration of each terminal device 10 constituting the wireless communication system 100 may be various, but in the following, the configuration common to each terminal device 10 will be described by taking the terminal device 10A as an example.

<Base station equipment>
As shown in the upper part of FIG. 2, the base station apparatus 20 is composed of at least a first communication unit 21, a second communication unit 22, a control unit 24, a memory 26, and the like. The first communication unit 21 is further composed of a transmission unit and a reception unit, and performs wireless communication such as data and messages with each terminal device 10 existing within the coverage of the base station device 20.

The second communication unit 22 is connected to another base station device 20 connected to the core network 30, or is a higher-level network device (MME (Mobility Management Entity), S-GW (Serving-Gateway), etc. in the core network 30). ) And the base station apparatus 20A to communicate a control message or user data.

The control unit 24 controls the operation of the base station device 20A. The control unit 24 controls the operation of the base station apparatus 20 by executing the program 27 stored in the memory 26. The control unit 24 further includes a handover control unit 25.

When the terminal device 10A performs a handover from the base station device 20A to the base station device 20B, for example, the transmitting unit transmits a signal for measuring the signal strength to the terminal device 10A, and the receiving unit receives the terminal device. The measurement result of the signal strength of the received signal is received from 10A. The base station device 20A may periodically transmit a reference signal to the terminal device 10A and periodically receive a measurement result from the terminal device 10A. Alternatively, the base station device 20A may periodically transmit a reference signal to the terminal device 10A and receive the measurement result only when the measurement result exceeds a predetermined threshold value. The handover control unit 25 of the control unit 24 generates a handover command to the terminal device 10A based on the measurement result of the signal strength of the received signal reported from the terminal device 10A.

The details of the handover process will be described later.
<Terminal device>
The lower part of FIG. 2 is a block diagram showing the configuration of the terminal device 10A included in the wireless communication system 100. The configuration of the terminal device 10A will be described with reference to the lower part of FIG.

As shown in the lower part of FIG. 2, the terminal device 10A is composed of at least a communication unit 11, an operation unit 12, a display unit 13, a control unit 14, and a memory 17. The communication unit 11 further includes a transmission unit and a reception unit, and performs wireless communication with the base station device 20A. The operation unit 12 accepts the user's operation of the terminal device 10A. The operation information regarding the operation content is sent to the control unit 14, and the control unit 14 controls the operation of the terminal device 10 according to the operation information.

The display unit 13 displays information necessary for the user, such as the communication status of the terminal device 10A, the communication method, and the content of the operation by the user. The operation unit 12 and the display unit 13 may be integrally configured.

The control unit 14 controls the operation of the terminal device 10A. The memory 17 stores the program 18, the application 19, and the like, and the control unit 14 controls the operation of the terminal device 10A by executing the stored program 18. The memory 17 may be any storage device such as a ROM, RAM, cache memory, and flash memory.

The control unit 14 further includes a handover execution unit 15 and a measurement unit 16.

The measuring unit 16 measures the signal strength of the reference signal transmitted from the base station device 20A (or the base station device 20B). Examples of the signal strength of the reference signal transmitted from the base station apparatus 20A measured by the measuring unit 16 include RSRP (reference signal reception power) or RSRQ (reference signal reception quality). The measuring unit 16 transmits the measurement result of the signal strength to the communication unit 11. The terminal device 10A may measure the signal strength of the reference signal according to the measurement command from the base station device 20A, or may periodically measure the reference signal transmitted periodically. The measuring unit 16 also measures the signal strength of the reference signal received from a base station device (for example, the base station device 20B) other than the base station device 20A existing in the vicinity.

The communication unit (transmission unit) 11 transmits the measurement result of the signal strength received from the measurement unit 16 to the base station device 20A. As described above, the base station device 20A issues a handover command to the terminal device 10A based on the measurement result of the signal strength. The communication unit (reception unit) 11 of the terminal device 10A receives the handover command from the base station device 20A. The handover execution unit 15 executes, for example, a handover process to the base station device 20B according to the handover command from the handover control unit 25 of the base station device 20A received by the communication unit (reception unit) 11. The details of the handover process will be described later.

<General flow of handover processing>
Hereinafter, an example of a general processing flow when the terminal device 10A hands over from the base station device 20A to the base station device 20B will be described.

Here, an example of a backward handover in which the source base station device 20A instructs the terminal device 10A to perform the handover is described in the handover between the base station devices 20 belonging to the same core network 30. 1. 1. The terminal device 10A has an established connection with the source base station device 20A, and is communicating data with the source base station device 20A. 2. 2. The terminal device 10A measures the signal strength of the reference signal from the source base station device 20A, the target base station device 20B, or both based on the measurement command from the source base station device 20A or periodically. The measurement result is reported to the base station apparatus 20A. 3. 3. The source base station apparatus 20A determines whether or not to perform the handover based on the reported measurement result. The source base station apparatus 20A determines whether or not to perform a handover based on the signal strength of the reference signal from the source base station apparatus 20A, the signal strength from the target base station apparatus 20B, or both. 4. When it is determined to execute the handover, the source base station apparatus 20A transmits a handover request to the target base station apparatus 20B, and transmits a handover command to the terminal apparatus 10A. 5. The untransmitted data is transferred from the source base station apparatus 20A to the target base station apparatus 20B. 6. Synchronize between the terminal device 10A and the target base station device 20B. 7. The target base station device 20B requests the core network to switch buses. 8. In the core network, the bus is switched to the destination base station device (base station device 20B). 9. Communication is established between the terminal device 10A and the target base station device 20B. The above is an explanation of an example of the flow of the handover process in the terminal device that performs wireless communication, and the handover process of one aspect of the present invention is not limited to the above-mentioned handover process.

<Overview of Handover Processing in Embodiment 1>
FIG. 3 is a conceptual diagram for explaining the outline of the handover process from the base station device 20A connected to the same core network 30 to the adjacent base station device 20B by the terminal device 10A. Hereinafter, the outline of the handover processing in the first embodiment will be described with reference to FIG.

As described above, the base station device 20A generates a handover command based on the measurement result of the reference signal reported from the terminal device 10A. In the first embodiment, a first threshold value W1 for performing handover processing and a second threshold value W2 smaller than the first threshold value W1 are set for the measurement result of the signal strength of the reference signal from the base station apparatus 20A. , Generates a handover command according to the relationship between the signal strength of the measurement result and the first threshold value W1 and the second threshold value W2.

FIG. 3 shows the coverage of the source base station device 20A, the coverage of the target base station device 20B, and the positional relationship of the moving terminal device 10. Inside the substantially circle X1 shown in FIG. 3, the reception intensity of the terminal device 10A from the base station device 20A is larger than the first threshold value W1. Outside the substantially circle X1 and inside the substantially circle X2, the reception intensity of the terminal device 10A is equal to or less than the first threshold value W1 and equal to or greater than the second threshold value W2. Outside the substantially circle X2, the reception intensity of the terminal device 10A is smaller than the second threshold value W2. The inside of the substantially circle X2 substantially coincides with the coverage X of the base station apparatus 20A.

The terminal device 10A moves to positions A, B, and C along the arrow l in FIG. As a result, the terminal device 10A initially exists in the coverage X of the base station device 20 of the base station device 20A, but eventually separates from the coverage X and enters the coverage Y of the base station device 20B.

The base station device 20A notifies the set first threshold value (W1) and the second threshold value (W2) by a radio resource setting signal (RRC Connection Reconfiguration or the like) with the terminal device 10A.

In FIG. 3, when the terminal device 10A is present at the position A, the terminal device 10A is included in both the coverage X of the base station device 20A and the coverage Y of the base station device 20B. At this point, since the terminal device 10 is located inside the substantially circle X1, the signal strength of the reference signal received from the base station device 20A is larger than the first threshold value W1. In this case, the base station apparatus 20A that has received the measurement result from the terminal apparatus 10A decides not to execute the handover.

When the terminal device 10A moves to the position B, the terminal device 10A is located outside the substantially circle X1 and inside the substantially circle X2. At this point, the signal strength of the reference signal from the base station device 20A in the terminal device 10A is equal to or less than the first threshold value W1 and equal to or higher than the second threshold value W2. In this case, the base station device 20A determines whether or not to perform the handover depending on the communication state of the terminal device 10A.

For example, when the terminal device 10A is executing a communication process such as downloading data from the base station device 20A or uploading data to the base station device 20A, the base station device 20A performs the process. Decides not to perform the handover until it is finished. Then, the base station device 20A may instruct the terminal device 10A to notify the terminal device 10A by the handover preparation command when the notification process is completed. Further, in this case, the base station device 20A may allocate a large amount of radio resources (frequency bandwidth, time, etc.) to the terminal device 10A so that the download or upload process can be completed earlier.

Further, in the base station device 20A, when the measurement result of the signal strength is equal to or less than the first threshold value W1 by the handover preparation command and the terminal device 10A is executing the communication process, the terminal device 10A May be instructed to notify the base station apparatus 20A of the amount of data remaining until the communication processing of the terminal apparatus 10A is completed. For example, when the terminal device 10A transmits the measurement result of the signal strength of the reference signal to the base station device 20A, the terminal device 10A notifies the base station device 20A including the remaining amount of data of the file being downloaded or uploaded. You may. Alternatively, the terminal device 10A may notify the base station device 20A of the remaining amount of data by another message.

When the communication process is completed, the terminal device 10A notifies the base station device 20A to that effect in accordance with the command from the base station device 20A. Upon receiving the notification, the base station device 20A instructs the terminal device 10A to execute the handover. The terminal device 10A executes the handover according to the instruction.

When the measurement result of the signal strength is equal to or greater than the second threshold value and equal to or less than the first threshold value, and the terminal device 10A has not performed communication processing such as data download or upload (in a standby state), The base station device 20A decides to perform the handover and orders the terminal device 10A to perform the handover. The terminal device 10A executes the handover according to the instruction.

Further, when the terminal device 10A moves to the position C, the terminal device 10A is located outside the substantially circle X2. At this point, the signal strength of the reference signal from the base station device 20A in the terminal device 10A is less than the second threshold value W2. In this case, the base station device 20A decides to immediately execute the handover even when the terminal device 10A is executing the communication process such as data download or upload, and instructs the terminal device 10A. The terminal device 10A executes the handover according to the instruction.

As described above, the threshold value of the signal strength that triggers the execution of the handover is set in two stages, and the handover processing is flexibly executed in consideration of whether or not the terminal device 10A is executing the communication processing. By deciding whether or not to perform the handover, it is possible to perform the handover at an appropriate timing without interfering with the processing such as downloading or uploading the data during execution.

The first threshold value W1 and the second threshold value W2 may be appropriately set. For example, the first threshold value W1 may be a value larger than the current threshold value W, and the second threshold value W2 may be the same threshold value as the current threshold value W. Alternatively, the first threshold value W1 may be the same as the current threshold value W, and the second threshold value W2 may be a communicable limit value. Alternatively, both the first threshold value W1 and the second threshold value W2 may be different from the current threshold value W.

<Handover procedure>
FIG. 4 is a sequence diagram showing an example of the flow of handover processing in the first embodiment. Hereinafter, the flow of the handover process in the first embodiment will be described with reference to FIG.

Communication has been established between the terminal device 10A and the base station device 20A (source base station device), and data is being downloaded from the base station device 20A (step S10). Prior to the establishment of communication, the base station apparatus 20A sets the threshold value of the reference signal from the base station apparatus 20A in the terminal apparatus 10A for performing the handover process when transmitting the radio resource setting signal to the terminal apparatus 10A. A second threshold value (W2) (W1> W2) smaller than the first threshold value (W1) and the first threshold value (W1) is set and notified to the terminal device 10A.

The terminal device 10A measures the signal strength of the reference signal from the base station device 20A periodically or according to a measurement command from the base station device 20A (step S12), and transmits the measurement result to the base station device 20A (step). S14). At this time, the terminal device 10A may transmit the measurement result and the magnitude relationship between the signal strength of the measurement result and the first threshold value W1 and the second threshold value W2 to the base station device 20A. For example, the terminal device 10A may notify that the signal strength of the reference signal is the first threshold value W1 or more and the second threshold value W2 or more. The terminal device 10A further notifies the base station device 20A that the data is being downloaded. Further, the terminal device 10A may notify the base station device 20A of the amount of data for the remaining downloads. Alternatively, the terminal device 10A may notify the base station device 20A of the remaining amount of data by another message.

The base station device 20A notifies the adjacent base station device 20B (target base station device) that there is a terminal device 10A that is likely to be handed over (step S16). The base station device 20A states that the measurement result of the signal strength of the reference signal from the terminal device 10A is equal to or less than the first threshold value W1 and equal to or higher than the second threshold value W2, and that the terminal device 10A is downloading data. Based on the information in the above, it is determined not to execute the handover until the terminal device 10A finishes downloading the data (step S18). At this time, in order to finish the data download earlier, a large amount of wireless resources may be allocated to the terminal device 10A.

The base station device 20A again issues a measurement command to the terminal device 10A (step S20), and the terminal device 10A reports the measurement result to the base station device 20A (step S22). When the terminal device 10A reports that the data download is completed, or when the signal strength from the base station device 20A in the terminal device 10A falls below the second threshold value W2, the base station device 20A performs a handover. Decide to do it. In this case, the base station device 20A transmits a handover request to the base station device 20B (step S24), and transmits a handover command to the terminal device 10A (step S26).

The terminal device 10A executes the handover to the base station device 20B in accordance with the handover command. As a result, communication is established between the terminal device 10A and the base station device 20B (step S28).

As described above, the signal strength of the base station device 20A (source base station device) that triggers the execution of the handover is set in two stages, and even if the signal strength falls below the first stage, the terminal device 10 is executing the communication process. In some cases, if the handover is not executed until the communication processing is completed, it is possible to prevent waste such as communication obstruction or re-transmission due to frequent handover, which is appropriate. Handover can be executed at any timing.

[Embodiment 2] In the first embodiment, a two-step threshold value is set for the signal strength of the reference signal from the base station device 20A (source base station device) of the movement source, and it is determined whether or not to execute the handover. The embodiment has been described as an example. In the second embodiment, an embodiment in which a two-step threshold value is set for the signal strength of the reference signal from the destination base station device 20B (target base station device) will be described. However, since the configurations of the wireless communication system, the base station device, and the terminal device according to the second embodiment are the same as those of the first embodiment, illustration and description thereof will be omitted.

<Overview of Handover Processing in Embodiment 2>
FIG. 5 is a conceptual diagram for explaining the outline of the handover process in the second embodiment of the present invention. Hereinafter, the procedure for the terminal device 10A to hand over from the base station device 20A to the base station device 20B will be described with reference to FIG.

As described above, the base station device 20A generates a handover instruction based on the measurement result of the reference signal of the base station device 20B reported from the terminal device 10A. The base station device 20A sets and measures a third threshold value W3 for performing handover processing and a fourth threshold value W4 larger than the third threshold value W3 for the signal strength of the signal received from the base station device 20B. A handover instruction is generated according to the relationship between the resulting signal strength and the third threshold value W3 and the fourth threshold value W4.

FIG. 5 shows the coverage of the source base station device 20A, the coverage of the target base station device 20B, and the positional relationship of the moving terminal device 10. Inside the substantially circle Y1 centered on the base station device 20B shown in FIG. 5, the reception strength of the signal from the base station device 20B of the terminal device 10A is larger than the fourth threshold value W4. Outside the substantially circle Y1 and inside the substantially circle Y2, the reception intensity of the terminal device 10A is equal to or less than the fourth threshold value W4 and equal to or greater than the third threshold value W3. Outside the substantially circle Y2, the reception intensity of the terminal device 10A is smaller than the third threshold value W3. The inside of the substantially circle Y2 substantially coincides with the coverage Y of the base station apparatus 20B.

The terminal device 10A moves to positions A, B, and C along the arrow l in FIG. As a result, the terminal device 10A initially exists in the coverage X of the base station device 20 of the base station device 20A, but eventually separates from the coverage X and enters the coverage Y of the base station device 20B. In the terminal device 10A, since the reception intensity from the base station device 20A currently in the service area is lowered, the peripheral base station measurement is performed. As a result, the measurement of the reception strength of the signal from the base station apparatus 20B is started.

The base station device 20A notifies the set third threshold value (W3) and the fourth threshold value (W4) by a radio resource setting signal (RRCconnection Reconfiguration, etc.) with the terminal device 10A.

In FIG. 5, when the terminal device 10A is present at the position A, the terminal device 10A is included in both the coverage X and Y of the base station device 20A and the base station device 20B. At this point, since the terminal device 10 is located outside the substantially circle Y2, the signal strength of the reference signal received from the base station device 20B is smaller than the third threshold value W3. In this case, the base station apparatus 20A that has received the measurement result from the terminal apparatus 10A decides not to execute the handover.

When the terminal device 10A moves to the position B, the terminal device 10A is located outside the substantially circle Y1 and inside the substantially circle Y2. At this point, the signal strength of the reference signal from the base station device 20B in the terminal device 10A is equal to or less than the fourth threshold value W4 and equal to or higher than the third threshold value W3. In this case, the base station device 20A determines whether or not to perform the handover depending on the communication state of the terminal device 10A.

For example, when the terminal device 10A is executing a communication process such as downloading data from the base station device 20A or uploading data to the base station device 20A, the base station device 20A performs the process. Decides not to perform the handover until it is finished. Then, the base station device 20A may instruct the terminal device 10A to notify the terminal device 10A when the communication processing is completed by the handover preparation command. Further, in this case, the base station apparatus 20A may allocate a large amount of resources (time, frequency, etc.) to the terminal apparatus 10A so that the data download or upload process can be completed earlier.

Further, in the base station device 20A, when the measurement result of the signal strength is equal to or higher than the third threshold value W3 by the handover preparation command and the terminal device 10A is executing the communication process, the terminal device 10A May be instructed to notify the base station apparatus 20A of the amount of data remaining until the communication processing of the terminal apparatus 10A is completed. For example, when the terminal device 10A reports the measurement result of the signal strength of the reference signal to the base station device 20A, the terminal device 10A notifies the base station device 20A including the remaining data amount of the file being downloaded or uploaded. You may. Alternatively, it may be notified by another message.

When the communication process is completed, the terminal device 10A notifies the base station device 20A to that effect in accordance with the command from the base station device 20A. Upon receiving the notification, the base station device 20A instructs the terminal device 10A to execute the handover process. The terminal device 10A executes the handover according to the instruction.

When the terminal device 10A has moved to the position B and the terminal device 10A has not performed communication processing such as data download or upload (in a standby state), the base station device 20A shall execute a handover. Is determined, and the terminal device 10A is instructed to execute the handover process. The terminal device 10A executes the handover according to the instruction.

Further, when the terminal device 10A moves to the position C, the terminal device 10A is located inside the substantially circle Y1. At this point, the signal strength of the measurement result from the base station device 20B in the terminal device 10A exceeds the fourth threshold value W4. In this case, the base station device 20A decides to immediately execute the handover even when the terminal device 10A is executing the communication process such as data download or upload, and instructs the terminal device 10A. The terminal device 10A executes the handover according to the instruction.

As described above, for the measurement result of the signal from the target base station device, the threshold value of the signal strength that triggers the execution of the handover is set in two stages, and whether or not the terminal device 10A is executing the communication process is determined. By flexibly deciding whether or not to execute the handover process in consideration of the above, the handover can be performed at an appropriate timing without interfering with the process such as downloading or uploading the data being executed.

The third threshold value W3 and the fourth threshold value W4 may be appropriately set. For example, the fourth threshold value W4 may be a value larger than the current threshold value W, and the third threshold value W3 may be the same threshold value as the current threshold value W. Alternatively, the fourth threshold value W4 may be the same as the current threshold value W. Alternatively, the third threshold value W3 and the fourth threshold value W4 may be different from the current threshold value W.

<Handover procedure>
FIG. 6 is a sequence diagram showing an example of the flow of handover processing in the second embodiment. Hereinafter, the flow of the handover process in the second embodiment will be described with reference to FIG.

Wireless communication has been established between the terminal device 10A and the base station device 20A (source base station device), and data is being downloaded from the base station device 20A (step S110). Prior to the establishment of communication, the base station apparatus 20A receives a reference signal from the base station apparatus 20A in the terminal apparatus 10A for performing a handover process when transmitting a radio resource setting signal to and from the terminal apparatus 10A. As the threshold value, the terminal device 10A is notified of the third threshold value (W3) and the fourth threshold value (W4) (W4> W3) larger than the third threshold value (W3).

The terminal device 10A measures the signal strength of the reference signal from the base station device 20B periodically or according to a measurement command from the base station device 20A (step S112), and transmits the measurement result to the base station device 20A (step). S114). At this time, the terminal device 10A may transmit the measurement result and the magnitude relationship between the signal strength of the measurement result and the third threshold value W3 and the fourth threshold value W4 to the base station device 20A. For example, the terminal device 10A may notify that the signal strength of the reference signal is the third threshold value W3 or more and the fourth threshold value W4 or less. The terminal device 10A also notifies the base station device 20A that the data is being downloaded. Further, the terminal device 10A may notify the base station device 20A of the amount of data for the remaining downloads. Alternatively, the terminal device 10A may notify the base station device 20A of the remaining amount of data by another message.

The base station device 20A may notify the adjacent base station device 20B (target base station device) that there is a terminal device 10A that is likely to be handed over (step S116). The base station device 20A states that the measurement result of the signal strength of the reference signal from the terminal device 10A is equal to or higher than the third threshold value W3 and equal to or lower than the fourth threshold value W4, and that the terminal device 10A is downloading data. Based on the information in the above, it is determined not to execute the handover until the terminal device 10A finishes downloading the data (step S118). At this time, in order to finish the data download earlier, a large amount of wireless resources may be allocated to the terminal device 10A.

The base station device 20A again issues a measurement command to the terminal device 10A (step S120), and the terminal device 10A transmits the measurement result to the base station device 20A (step S122). When the terminal device 10A reports that the data download is completed, or when the signal strength from the base station device 20B in the terminal device 10A exceeds the fourth threshold value W4, the base station device 20A performs a handover. Decide to do it. Then, the base station device 20A transmits a handover request to the base station device 20B (step S124), and transmits a handover command to the terminal device 10A (step S126).

As described above, even if the signal strength of the base station device 20B (target base station device) that is the trigger for executing the handover is set in two stages and exceeds the first stage (the above-mentioned third threshold value W3), the terminal device When the 10A is executing the communication process, if the configuration is such that the handover is not executed until the communication process is completed, the communication is hindered or re-transmission is required due to the frequent occurrence of the handover. Waste can be prevented, and handover can be executed at an appropriate timing.

[Embodiment 3] In the above embodiment, the communication state is set when the threshold value of the measurement result that can trigger the handover is set in two stages and the terminal device 10A is downloading or uploading data from the base station device 20A. The case of deciding whether or not to perform handover in consideration has been described as an example.

The embodiment according to one aspect of the present invention is not limited to this, and can be applied even when the terminal device 10A is performing a process other than downloading or uploading data. For example, as shown in FIG. 7, when the terminal device 10A frequently enters and exits the coverage near the end of the coverage of the base station device 20A, it is necessary to suppress the frequent occurrence of handover.

Examples of the processing being executed by the terminal device 10A include the following processing in addition to downloading data from the base station device 20A or uploading data to the base station device 20A.
-When the terminal device 10A is in a call. In this case, the handover may be executed at the timing when both terminal devices during the call become silent or when the call ends.
-When the terminal device 10A is executing streaming playback, live distribution, online conference, or the like. In this case, the handover may be executed when there is no sound or when there is little screen update due to a still image. However, if there is sufficient margin in the buffer, the handover may be executed even if these processes are being executed.
-If SMS (Short Message Service) is being transmitted / received, the handover may be executed after SMS transmission / reception.
-If the online game is in progress, the handover may be executed during loading or no operation.
-In the case of ultra-reliable ultra-low delay communication (during URLLC) such as automatic operation, handover is executed at the time of temporary stop.
-In the case of high-speed large-capacity communication (during eMBB) such as during large-capacity transmission, the handover is executed when the download of the first data is completed.
Further, depending on the application used in the terminal device 10A, whether or not to execute the handover may be changed during the processing.
-If the source base station device 20A or the target base station device 20B is dedicated to or supports URLLC or eMBB, the first threshold value W1 or the terminal device 10A depends on whether or not the terminal device 10A wants to use the function. Which of the second thresholds W2 may be used as the trigger for handover may be determined. For example, even if the terminal device 10A is downloading data, if the target base station device 20B is dedicated to eMBB (enhanced mobile broadband), it is necessary to execute the handover as soon as possible.

[Embodiment 4] FIG. 8 is a block diagram showing the configuration of the terminal device 10A according to the present embodiment. In the present embodiment, the terminal device 10A further includes a position detection unit 141 that detects the position of the terminal device 10A itself, and a base station device in the terminal device 10A based on the moving speed and moving direction of the detected position of the terminal device 10A. It may include an estimation unit 142 that estimates the time required for the signal strength of the received signal from 20A to fall below the first threshold value W1 or the second threshold value W2. For example, the terminal device 10A is provided with a GPS (Global Positioning System) and is configured to be able to detect the position of the terminal device 10A itself. Then, the estimation unit 142 provided in the terminal device estimates the future movement trajectory of the terminal device 10A on the assumption that the movement direction and the movement speed of the terminal device 10A itself are maintained. Thereby, it is possible to estimate the time when the measurement result of the received signal from the base station device 20A in the terminal device 10A reaches the first threshold value or the second threshold value. As a result, the handover preparation can be performed in advance, and the handover can be smoothly executed.

[Other Embodiments] In the above embodiment, the backward handover in which the base station device 20A notifies the terminal device 10A of the base station device to be switched to has been described. However, the above embodiment is not limited to this, and may be a forward handover in which the terminal device 10A autonomously captures the switching destination base station device.

For example, the terminal device 10A executes a handover process from the base station device 20A to the base station device 20B based on the measurement unit that measures the signal strength of the received signal from the base station device 20A and the measurement result. It has a department. In the handover process, the terminal device 10A sets a first threshold value W1 for performing the handover process and a second threshold value W2 smaller than the first threshold value W1. Then, the handover process is executed according to the relationship between the signal strength of the measurement result and the first threshold value W1 and the second threshold value W2.

When the signal strength of the received signal is equal to or higher than the second threshold value W2 and equal to or lower than the first threshold value W1 and the terminal device 10A is executing the communication processing, the handover is performed when the communication processing is completed. If the processing is executed and the signal strength of the measurement result is equal to or greater than the second threshold value W2 and equal to or less than the first threshold value W1 and the terminal device 10A is not executing the communication processing, the handover may be executed. ..

Further, regarding the measurement result of the reference signal from the base station device 20B which is the target base station device, a threshold value that can be a trigger for handover is set in two stages, and the handover is executed in consideration of the communication state of the terminal device together with the measurement result. It may be configured to determine whether or not to do so.

For example, the terminal device 10A includes a measurement unit that measures the signal strength of the signal received from the base station device 20B, and an execution unit that executes a handover process from the base station device 20A to the base station device 20B based on the measurement result. To prepare for. In the handover process, a third threshold value W3 for performing the handover process and a fourth threshold value W4 larger than the third threshold value W3 are set, and the signal strength of the received signal and the third threshold value W3 and the fourth threshold value W3 are set. Handover processing is executed according to the relationship with the threshold value W4.

When the measurement result of the signal strength is the third threshold value W3 or more and the fourth threshold value W4 or less, and the terminal device 10A is executing the communication processing, the handover is performed when the communication processing is completed. If the processing is executed and the signal strength of the measurement result is equal to or higher than the third threshold value W3 and equal to or lower than the fourth threshold value W4, and the terminal device 10A is not executing the communication processing, the handover may be executed. ..

The terminal device 10A according to one aspect of the present invention may be a terminal device for handing over a base station device between different RATs (RadioAccess Technology). For example, it may be a transition from LTE to 3G, or a transition from LTE to 3G.

In addition, it can also be applied to terminal devices that execute handover between sectors of base station devices and between base station devices belonging to different core networks.

[Summary] [Aspect 1] The terminal device according to the first aspect of the present invention is a terminal device that performs wireless communication, and has a measuring unit for measuring the signal strength of a signal received from the first base station device and the signal. From the transmitting unit that transmits the intensity measurement result to the first base station device, the receiving unit that receives the handover command from the first base station device based on the measurement result, and the first base station device. The first base station apparatus includes a handover execution unit that executes a handover process to the second base station apparatus according to the handover command of the above, and the first base station apparatus has a first threshold value for performing the handover process and the first one. A second threshold value smaller than the threshold value of 1 is set, and a handover command is generated according to the relationship between the signal strength of the measurement result and the first threshold value and the second threshold value.

According to the above configuration, by providing two threshold values for the signal strength of the received signal from the base station device of the mobile source, frequent handover can be prevented and handover can be performed at an appropriate timing.

[Aspect 2] In the terminal device according to the second aspect of the present invention, in addition to the transmission of the measurement result, the signal strength of the measurement result and the magnitude relationship between the first threshold value and the second threshold value are determined. It may be transmitted to the first base station apparatus.

According to the above configuration, it is possible to determine that the handover is performed at an appropriate timing from the relationship between the two set threshold values and the magnitude of the measurement result.

[Aspect 3] The terminal device according to the third aspect of the present invention has the position detection unit for detecting the position of the terminal device itself, and the movement speed and the moving direction of the detected position of the terminal device in the first to second aspects. Therefore, the terminal device may include an estimation unit that estimates the time required for the signal strength of the received signal from the first base station device to fall below the first threshold value or the second threshold value.

According to the above configuration, by estimating the movement of the terminal device, the handover can be dealt with at an early stage, and the handover can be executed at an appropriate timing.

[Aspect 4] The terminal device according to the fourth aspect of the present invention is the case where the measurement result of the signal strength of the first base station device is equal to or less than the first threshold value by the handover preparation command in the first to third aspects. Moreover, when the terminal device is executing the communication process, the terminal device may be instructed to notify the first base station device of the amount of data remaining until the communication process is completed.

According to the above configuration, the base station apparatus captures the remaining amount of data during communication in advance, so that the handover can be executed at an appropriate timing.

[Aspect 5] In the terminal device according to the fifth aspect of the present invention, in the first to fourth aspects, the first base station device has the signal strength measurement result equal to or higher than the second threshold value by the handover preparation command. When the value is equal to or less than the first threshold value and the terminal device is executing the communication process, the terminal device is contacted with respect to the first base station device when the communication process is completed. The first base station apparatus receives a notification from the terminal apparatus that the communication processing has been completed by the handover command. The terminal device is instructed to execute the handover process, the measurement result of the signal strength is equal to or higher than the second threshold value and equal to or lower than the first threshold value, and the terminal device executes the communication process. If not, the terminal device may be instructed to execute the handover process.

According to the above configuration, it is possible to determine that the handover is performed at an appropriate timing in consideration of the communication state of the terminal device in addition to the measurement result of the signal strength from the base station device.

[Aspect 6] In the terminal device according to the sixth aspect of the present invention, in the first aspect, when the signal strength of the measurement result is less than the second threshold value by the handover command, the first base station device is the terminal device. May be instructed to execute the handover process even while the communication process is being executed.

According to the above configuration, the handover can be performed at an appropriate timing.

[Aspect 7] The terminal device according to aspect 7 of the present invention is a terminal device that performs wireless communication, and has a measuring unit that measures the signal strength of a signal received from a second base station device and a measurement result of the signal strength. A second unit according to a transmitter unit that transmits The first base station apparatus includes an execution unit for executing the handover processing to the base station apparatus, and the first base station apparatus sets a third threshold value for performing the handover processing and a fourth threshold value larger than the third threshold value. , Generates a handover command according to the relationship between the signal strength of the measurement result and the third threshold value and the fourth threshold value.

According to the above configuration, it is possible to decide to perform the handover at an appropriate timing.

[Aspect 8] In the terminal device according to the aspect 8 of the present invention, in the seventh aspect, the first base station device is in the case where the signal strength of the measurement result is equal to or higher than the third threshold value by the handover preparation command. If the terminal device is executing the communication process, the terminal device may be instructed to notify the first base station device of the amount of data remaining until the communication process is completed.

[Aspect 9] In the terminal device according to the aspect 9 of the present invention, in the first base station device, the measurement result of the signal strength is equal to or higher than the third threshold value by the handover preparation command. If it is equal to or less than the threshold value of 4, and the terminal device is executing the communication process, the communication process for the first base station device is completed when the communication process for the terminal device is completed. The first base station device is instructed to notify the fact, and when the terminal device notifies that the communication process is completed by the handover command, the first base station device executes the handover process to the terminal device. If the signal strength measurement result is equal to or higher than the third threshold value and equal to or lower than the fourth threshold value, and the terminal device is not executing the communication process, the terminal device is subjected to the handover process. You may instruct it to do so.

[Aspect 10] In the terminal device according to the present invention, in the seventh aspect, in the handover command, when the signal strength of the measurement result exceeds the fourth threshold value, the terminal device performs communication processing. You may instruct to execute the handover process even during execution.

[Aspect 11] The terminal device according to the aspect 11 of the present invention is a terminal device that performs wireless communication, and is based on a measurement unit that measures a signal strength of a signal received from a first base station device and a measurement result. , A terminal device including an execution unit that executes a handover process from the first base station device to the second base station device, the first threshold value for performing the handover process in the handover process, and the first. A second threshold value smaller than the threshold value of 1 is set, and the handover process is executed according to the relationship between the signal strength of the measurement result and the first threshold value and the second threshold value.

[Aspect 12] In the terminal device according to the aspect 12 of the present invention, in the aspect 11, the signal strength of the measurement result is equal to or higher than the second threshold value and equal to or lower than the first threshold value, and the terminal device is executing the communication process. If, the handover process is executed when the communication process is completed, the signal strength of the measurement result is equal to or higher than the second threshold value and equal to or lower than the first threshold value, and the terminal device is executing the communication process. If not, the handover may be executed.

[Aspect 13] The terminal device according to aspect 13 of the present invention is a terminal device that performs wireless communication, and is based on a measurement unit that measures the signal strength of a signal received from a second base station device and a measurement result. , A terminal device including an execution unit that executes a handover process from the first base station device to the second base station device, and a third threshold value for performing the handover process in the handover process, and a third. A fourth threshold value larger than the threshold value of 3 is set, and the handover process is executed according to the relationship between the signal strength of the measurement result and the third threshold value and the fourth threshold value.

[Aspect 14] In the terminal device according to the aspect 14 of the present invention, in the aspect 13, the signal strength of the measurement result is equal to or higher than the third threshold value and equal to or lower than the fourth threshold value, and the terminal device is executing the communication process. If, the handover process is executed when the communication process is completed, the signal strength of the measurement result is equal to or higher than the third threshold value and equal to or lower than the fourth threshold value, and the terminal device is executing the communication process. If not, the handover may be executed.

[Aspect 15] The base station apparatus according to the aspect 15 of the present invention is a base station apparatus that performs wireless communication, and is a receiving unit that receives a measurement result of a signal strength of a signal received from the base station apparatus in the terminal apparatus. A control unit that generates a handover command for the terminal device based on the measurement result of the signal strength is provided, and the control unit has a first threshold value for performing the handover process and a second threshold value smaller than the first threshold value. The threshold value of is set, and a handover command is generated according to the relationship between the signal strength of the measurement result and the first threshold value and the second threshold value.

[Aspect 16] In the base station apparatus according to the 16th aspect of the present invention, in the 15th aspect, the control unit has a signal strength measurement result of the second threshold value or more and the first threshold value or less by the handover preparation command. In addition, when the terminal device is executing the communication process, the terminal device is instructed to notify that the communication process is completed when the communication process is completed, and the control unit gives a handover command. When the notification that the communication processing is completed is received from the terminal device, the terminal device is instructed to execute the handover processing, and the measurement result of the signal strength is equal to or higher than the second threshold value. If it is equal to or less than the threshold value of 1 and the terminal device is not executing the communication process, the terminal device may be instructed to execute the handover process.

[Aspect 17] The base station apparatus according to the aspect 17 of the present invention is a base station apparatus that performs wireless communication, and receives a measurement result of a signal strength of a signal received from a second base station apparatus from a terminal apparatus. A receiving unit, a control unit that generates a handover command for the terminal device based on the measurement result of the signal strength, and a transmission unit that transmits the generated handover command to the terminal device are provided, and the control unit performs the handover process. A third threshold value for performing the operation and a fourth threshold value larger than the third threshold value are set, and a handover command is issued according to the relationship between the signal strength of the measurement result and the third threshold value and the fourth threshold value. Generate.

[Aspect 18] In the base station apparatus according to the aspect 18 of the present invention, in the aspect 17, the control unit receives a handover preparation command and the signal strength measurement result is equal to or higher than the third threshold value and lower than the fourth threshold value. If there is, and the terminal device is executing the communication process, the terminal device is instructed to notify that the communication process is completed when the communication process is completed, and the control unit is instructed to notify that the communication process is completed. When the terminal device receives a notification that the communication process is completed by the handover command, the terminal device is instructed to execute the handover process, and the measurement result of the signal strength is equal to or higher than the third threshold value. If the value is equal to or less than the fourth threshold value and the terminal device is not executing the communication process, the terminal device may be instructed to execute the handover process.

Further, each functional block or various features of the device used in the above-described embodiment can be implemented or executed in an electric circuit, for example, an integrated circuit or a plurality of integrated circuits. Electrical circuits designed to perform the functions of this embodiment may be general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic. It may include devices, discrete gates or transistor logic, discrete hardware components, or a combination thereof.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

Claims

It is a terminal device that performs wireless communication.
A measuring unit that measures the signal strength of the received signal from the first base station device,
A transmission unit that transmits the measurement result of the signal strength to the first base station device, and
A receiving unit that receives a handover command from the first base station device based on the measurement result, and
A handover execution unit that executes a handover process to the second base station device according to the handover command from the first base station device is provided.
The first base station device is
A first threshold value for performing the handover process and a second threshold value smaller than the first threshold value are set.
A terminal device comprising generating a handover command according to the relationship between the signal strength of the measurement result and the first threshold value and the second threshold value.
According to claim 1, the terminal device transmits the measurement result and also transmits the magnitude relationship between the signal strength of the measurement result and the first threshold value and the second threshold value to the first base station device. The terminal device described.
The terminal device further includes a position detection unit that detects the position of the terminal device itself.
From the detected moving speed and moving direction of the position of the terminal device, until the signal strength of the received signal from the first base station device in the terminal device falls below the first threshold value or the second threshold value. The terminal device according to claim 1 or 2, further comprising an estimation unit for estimating the required time of the above.
In the first base station apparatus, when the measurement result of the signal strength is equal to or less than the first threshold value by the handover preparation command and the terminal apparatus is executing the communication process, the first base station apparatus is described. The terminal device according to any one of claims 1 to 3, which instructs the terminal device to notify the first base station device of the amount of data remaining until the communication process is completed.
The first base station device receives a handover preparation command.
When the measurement result of the signal strength is equal to or higher than the second threshold value and equal to or lower than the first threshold value, and the terminal device is executing the communication process, the communication process is performed with respect to the terminal device. Is instructed to notify the first base station apparatus that the communication processing is completed, and is instructed to notify that the communication processing is completed.
The first base station device receives the handover command.
Upon receiving a notification from the terminal device that the communication process has been completed, the terminal device is instructed to execute the handover process.
When the measurement result of the signal strength is equal to or higher than the second threshold value and equal to or lower than the first threshold value, and the terminal device is not executing the communication process, the handover process is executed for the terminal device. The terminal device according to any one of claims 1 to 4, wherein the terminal device is instructed to do so.
When the signal strength of the measurement result is less than the second threshold value by the handover command, the first base station device executes the handover process even while the terminal device is executing the communication process. The terminal device according to claim 1, wherein the terminal device is instructed to do so.
It is a terminal device that performs wireless communication.
A measuring unit that measures the signal strength of the signal received from the second base station device,
A transmission unit that transmits the measurement result of the signal strength to the first base station device, and
A receiving unit that receives a handover command from the first base station device based on the measurement result, and
An execution unit that executes a handover process to the second base station device according to a handover command from the first base station device is provided.
The first base station device is
A third threshold value for performing the handover process and a fourth threshold value larger than the third threshold value are set.
A terminal device comprising generating a handover command according to the relationship between the signal strength of the measurement result and the third threshold value and the fourth threshold value.
In the first base station apparatus, when the signal strength of the measurement result is equal to or higher than the third threshold value by the handover preparation command and the terminal apparatus is executing the communication process, the first base station apparatus is described. The terminal device according to claim 7, wherein the terminal device is instructed to notify the first base station device of the amount of data remaining until the communication process is completed.
The first base station device receives a handover preparation command.
When the measurement result of the signal strength is equal to or higher than the third threshold value and equal to or lower than the fourth threshold value, and the terminal device is executing the communication process, the communication process is performed with respect to the terminal device. Is instructed to notify the first base station apparatus that the communication processing is completed, and is instructed to notify that the communication processing is completed.
The first base station device receives the handover command.
Upon receiving a notification from the terminal device that the communication process has been completed, the terminal device is instructed to execute the handover process.
When the measurement result of the signal strength is equal to or higher than the third threshold value and equal to or lower than the fourth threshold value, and the terminal device is not executing the communication process, the handover process is executed for the terminal device. The terminal device according to claim 7 or 8, wherein the terminal device is ordered to do so.
When the signal strength of the measurement result exceeds the fourth threshold value in the handover command, the first base station device executes the handover process even while the terminal device is executing the communication process. 7. The terminal device according to claim 7.
It is a terminal device that performs wireless communication.
A measuring unit that measures the signal strength of the received signal from the first base station device,
A terminal device including an execution unit that executes a handover process from the first base station device to the second base station device based on the measurement result of the signal strength.
In the handover process,
A first threshold value for performing the handover process and a second threshold value smaller than the first threshold value are set.
A terminal device characterized in that a handover process is executed according to the relationship between the signal strength of the measurement result and the first threshold value and the second threshold value.
If the signal strength of the measurement result is equal to or higher than the second threshold value and equal to or lower than the first threshold value, and the terminal device is executing the communication process, the handover is performed when the communication process is completed. Execute the process and
The terminal according to claim 11, wherein if the signal strength of the measurement result is equal to or higher than the second threshold value and equal to or lower than the first threshold value, and the terminal device is not executing the communication process, the handover is executed. Device.
It is a terminal device that performs wireless communication.
A measuring unit that measures the signal strength of the signal received from the second base station device,
A terminal device including an execution unit that executes a handover process from the first base station device to the second base station device based on the measurement result of the signal strength.
In the handover process,
A third threshold value for performing the handover process and a fourth threshold value larger than the third threshold value are set.
A terminal device characterized in that a handover process is executed according to the relationship between the signal strength of the measurement result and the third threshold value and the fourth threshold value.
If the signal strength of the measurement result is equal to or higher than the third threshold value and equal to or lower than the fourth threshold value, and the terminal device is executing the communication process, the handover is performed when the communication process is completed. Execute the process and
The terminal according to claim 13, wherein if the signal strength of the measurement result is equal to or higher than the third threshold value and equal to or lower than the fourth threshold value, and the terminal device is not executing the communication process, the handover is executed. Device.
It is a base station device that performs wireless communication.
In the terminal device, a receiving unit that receives the measurement result of the signal strength of the received signal from the base station device, and
A control unit that generates a handover command for the terminal device based on the measurement result of the signal strength is provided.
The control unit sets a first threshold value for performing the handover process and a second threshold value smaller than the first threshold value.
A base station apparatus comprising generating a handover command according to the relationship between the signal strength of the measurement result and the first threshold value and the second threshold value.
The control unit receives a handover preparation command.
When the measurement result of the signal strength is equal to or higher than the second threshold value and equal to or lower than the first threshold value, and the terminal device is executing the communication process, the communication process is performed with respect to the terminal device. Is instructed to notify that the communication process is completed when the communication process is completed.
The control unit receives the handover command.
Upon receiving a notification from the terminal device that the communication process has been completed, the terminal device is instructed to execute the handover process, and the measurement result of the signal strength is equal to or higher than the second threshold value. The base station according to claim 15, wherein when the value is equal to or less than the first threshold value and the terminal device is not executing the communication process, the terminal device is instructed to execute the handover process. Device.
It is a base station device that performs wireless communication.
A receiving unit that receives the measurement result of the signal strength of the received signal from the second base station device from the terminal device, and
A control unit that generates a handover command for the terminal device based on the measurement result of the signal strength, and a control unit.
A transmission unit that transmits the generated handover command to the terminal device is provided.
The control unit
A third threshold value for performing the handover process and a fourth threshold value larger than the third threshold value are set.
A base station apparatus comprising generating a handover command according to the relationship between the signal strength of the measurement result and the third threshold value and the fourth threshold value.
The control unit receives a handover preparation command.
When the measurement result of the signal strength is equal to or higher than the third threshold value and equal to or lower than the fourth threshold value, and the terminal device is executing the communication process, the communication process is performed with respect to the terminal device. Is instructed to notify that the communication process is completed when the communication process is completed.
The control unit receives the handover command.
Upon receiving a notification from the terminal device that the communication process has been completed, the terminal device is instructed to execute the handover process.
When the measurement result of the signal strength is equal to or higher than the third threshold value and equal to or lower than the fourth threshold value, and the terminal device is not executing the communication process, the handover process is executed for the terminal device. 17. The base station apparatus according to claim 17, which orders to do so.