WO2018198276A1

WO2018198276A1 - Base station device, terminal device, wireless communication system and terminal movement method

Info

Publication number: WO2018198276A1
Application number: PCT/JP2017/016779
Authority: WO
Inventors: 長谷川哲哉
Original assignee: 富士通株式会社
Priority date: 2017-04-27
Filing date: 2017-04-27
Publication date: 2018-11-01
Also published as: JP6889386B2; JPWO2018198276A1

Abstract

Provided is a base station device which is in a wireless communication system that includes: a terminal device; the base station device which uses a first communication scheme; and another base station device which uses a second communication scheme that differs from the first communication scheme. The base station device and the other base station device relay communications of the terminal device. The base station device includes: a reception unit that receives, from the terminal device in a first state, a move destination state indicating the state of the terminal device at a move destination which is a state of the terminal device in respect to the base station device and which is a state not supported by the second communication scheme; and a transmission unit that, when the terminal device moves to the other base station device, transmits to the other base station device the move destination state and context information relating to a communication path of the terminal device.

Description

Base station apparatus, terminal apparatus, wireless communication system, and terminal moving method

The present invention relates to a base station device, a terminal device, a wireless communication system, and a terminal moving method.

In recent years, IoT (Internet of Things) that connects various devices other than Internet-related devices such as personal computers to the Internet has attracted attention. Devices connected by IoT include, for example, household electrical appliances that are remotely operated, sensors that regularly transmit measurement results to a server, and the like. Since these devices have a small amount of communication and the number of communication, they may not always be wirelessly connected to the base station device. However, depending on the communication frequency of these devices, performing wireless connection with the base station device every time communication occurs consumes power for each communication, and power efficiency may not be good. Therefore, in the next generation (for example, 5G (fifth generation mobile communication)) communication standard, the base station apparatus is not wirelessly connected and is in the communication area of the base station apparatus (for example, , IDLE state) and a state in which the wireless connection is established with the base station apparatus and wireless communication is possible (for example, CONNECTED state), and communication with a small amount of data is performed without transitioning to the CONNECTED state. An INACTIVE state that can do this is being investigated.

The technology relating to the intermediate state in the communication system is described in the following Patent Documents 1 and 2.

JP 2016-154339 A Japanese Unexamined Patent Publication No. 2016-187224

However, the terminal apparatus in the INACTIVE state moves to a base station apparatus (for example, a 4G (4th generation mobile communication) base station apparatus) of a communication method (RAT: Radio Access Technology) different from that of the base station apparatus performing wireless communication. There is a case.

It is assumed that the terminal device in the INACTIVE state moves the base station device by celery selection, for example, and enters the IDLE state in the destination base station device. In this case, the terminal apparatus updates the position information for the base station apparatus by performing a TAU (Tracking Area Update) procedure for the destination base station apparatus.

On the other hand, it is assumed that the terminal device in the INACTIVE state moves the base station device by, for example, inter-RAT handover and enters the CONNECTED state in the destination base station device. In this case, an inter-RAT handover procedure is performed between the terminal device and the source and destination base station devices.

As described above, in any case, if the terminal device in the INACTIVE state moves to the base station device of the previous version, a procedure for the movement is necessary, and transmission / reception of messages accompanying the execution of the procedure is necessary. It becomes. By transmitting and receiving the message, the terminal device consumes power and uses radio resources.

Therefore, a first base station apparatus, a terminal apparatus, a wireless communication system, and a terminal moving method are provided that suppress a movement procedure associated with movement of the terminal apparatus to another RAT base station apparatus.

In one aspect, the terminal device includes a base station device of a first communication method, and another base station device of a second communication method different from the first communication method, the base station device and the other base A station apparatus is the base station apparatus in a wireless communication system that relays communication of the terminal apparatus, and is a state of the terminal apparatus with respect to the base station apparatus, and is in a state not supported by the second communication scheme. A receiving unit that receives a destination state indicating a state at a destination of the terminal device from a terminal device in the state, and when the terminal device moves to the other base station device, the destination state and the terminal device A transmission unit that transmits context information regarding the communication path to the other base station device.

One disclosure suppresses the movement procedure associated with the movement of the terminal device to the RAT base station device.

FIG. 1 is a diagram illustrating a configuration example of a wireless communication system 10. FIG. 2 is a diagram illustrating an example of state transition of the terminal device 100 connected to the first base station device 200. FIG. 3 is a diagram illustrating a configuration example of the first base station apparatus 200. FIG. 4 is a diagram illustrating a configuration example of the second base station apparatus 300. FIG. 5 is a diagram illustrating a configuration example of the terminal device 100. FIG. 6 is a diagram illustrating an example of a sequence of terminal movement processing in the wireless communication system 10. FIG. 7 is a diagram illustrating an example of a process flowchart of the movement request reception process S103. FIG. 8 is a diagram illustrating an example of a process flowchart of the movement confirmation reception process S105. FIG. 9 is a diagram illustrating an example of a sequence of terminal movement processing when CONNECTED is designated as the designated state by the terminal device 100. FIG. 10 is a diagram illustrating an example of a sequence of terminal movement processing when CONNECTED is designated as the designated state by the terminal device 100. FIG. 11 is a diagram illustrating an example of a sequence for performing a designated state determination process when the terminal apparatus 100 moves between base station apparatuses. FIG. 12 is a diagram illustrating an example of a process flowchart of the designated state determination process S401. FIG. 13 is a diagram illustrating an example of a sequence of terminal movement processing in the wireless communication system 10. FIG. 14 is a diagram illustrating an example of a process flowchart of the designated state determination process S501. FIG. 15 is a diagram illustrating an example of a specified parameter list. FIG. 16 is a diagram illustrating an example of a process flowchart of the movement request reception process S503. FIG. 17 is a diagram illustrating an example of a process flowchart of the movement confirmation reception process S505. FIG. 18 is a diagram illustrating an example of a sequence of terminal movement processing in the wireless communication system 10. FIG. 19 is a diagram illustrating an example of a process flowchart of the movement request reception process S602. FIG. 20 is a diagram illustrating an example of a sequence of terminal movement processing in the wireless communication system 10.

Hereinafter, the present embodiment will be described in detail with reference to the drawings. Problems and examples in the present specification are merely examples, and do not limit the scope of rights of the present application. In particular, even if the described expressions are different, as long as they are technically equivalent, the techniques of the present application can be applied even if the expressions are different, and the scope of rights is not limited.

[First embodiment]
A first embodiment will be described.

<Configuration example of wireless communication system>
FIG. 1 is a diagram illustrating a configuration example of a wireless communication system 10. The radio communication system 10 includes a terminal device 100, a first base station device 200, a second base station device 300, and an NR-CN (New Radio-Core Network) 400.

The terminal device 100 is a mobile communication device such as a smartphone or a tablet terminal. For example, the terminal device 100 is wirelessly connected to the first base station device 200 or the second base station device 300, and communicates with an external network or another communication device.

1st base station apparatus 200 is a base station apparatus of a 1st communication system (for example, 5G). The first base station apparatus 200 is, for example, a gNodeB that is wirelessly connected to the terminal apparatus 100 and relays communication performed by the terminal apparatus 100. The first base station apparatus 200 has a communication area A200. The communication area is a range in which the first base station apparatus 200 can wirelessly connect to the terminal apparatus 100.

2nd base station apparatus 300 (other base station apparatus) is a base station apparatus of the 2nd communication system (for example, 4G) different from a 1st communication system. The second base station device 300 is an eNodeB (evolved Node B) that wirelessly connects to the terminal device 100 and relays communication performed by the terminal device 100. The second base station apparatus 300 has a communication area A300.

The NR-CN 400 is a core network or control device that manages the first base station device 200 and the second base station device 300 and relays communication between the external network and the terminal device 100. The NR-CN 400 includes, for example, an MME (Mobility Management Entity) and an S-GW (Serving Gateway). In addition, the NR-CN 400 connects, for example, the second base station device 300 and the first base station device 200 which are base station devices of different communication schemes, so that the base station devices of the terminal device 100 (first base station) The movement of the device 200 and the second base station device 300) is realized.

The state indicating the connection state between the terminal device 100 and the second base station device 300 in the second communication method includes an IDLE state and a CONNECTED state.

The IDLE state is a state in which, for example, the terminal device 100 is in the communication area 200A of the second base station device 300, and the second base station device 300 recognizes the position information of the terminal device 100. For example, when there is an incoming call to the terminal device 100 in the IDLE state, the second base station device 300 can call the terminal device 100 using paging. For example, the terminal device 100 enters an IDLE state when waiting for no data communication.

The CONNECTED state is a state in which, for example, the terminal device 100 and the second base station device 300 are wirelessly connected, and data communication such as packet transmission / reception can be performed between the terminal device 100 and the second base station device 300. For example, the terminal device 100 is in a CONNECTED state when performing a voice call or data communication.

The state indicating the connection state between the terminal apparatus 100 and the first base station apparatus 200 in the first communication scheme includes an INACTIVE state in addition to the IDLE state and the CONNECTED state.

The INACTIVE state is a state in which, for example, the terminal device 100 can perform communication with a predetermined amount of data (for example, a data amount smaller than the amount of data that can be communicated in the CONNECTED state) without transitioning to the CONNECTED state. For example, ResumeID (identifier) that is an identifier in the INACTIVE state is assigned from the first base station device 200 to the terminal device 100 in the INACTIVE state. The terminal device 100 in the INACTIVE state uses, for example, a frequency band dedicated to the terminal device in the INACTIVE state used by the terminal device 100 in the INACTIVE state, and does not establish a connection in the RRC (Radio Resource Control) layer. Data can be transmitted to the station apparatus 200. The INACTIVE state is a state where the terminal apparatus 100 and the first base station apparatus 200 are not wirelessly connected (similar to the IDLE state), but the session between the first base station apparatus 200 and the NR-CN 400 is maintained. (Retained).

FIG. 2 is a diagram illustrating an example of state transition of the terminal device 100 connected to the first base station device 200. The state of the terminal device 100 in the second base station device 300 is two states, that is, the IDLE state and the CONNECTED state, but the state of the terminal device 100 in the first base station device 200 further has an INACTIVE state.

For example, the state transition of the terminal apparatus 100 in the second base station apparatus 300 is from the IDLE state to the CONNECTED state, or from the CONNECTED state to the IDLE state (T1). However, the state transition of the terminal apparatus 100 in the first base station apparatus 200 includes a transition T2 that transitions to or from the INACTIVE state, and a transition T3 in addition to the transition T1.

For example, when the terminal device 100 is energized, the terminal device 100 transmits position information to the adjacent first or second base station device, and enters the IDLE state which is the initial state. When the terminal device 100 communicates with the first base station device 200, the terminal device 100 transitions from the IDLE state to, for example, the INACTIVE state (T2). On the other hand, when the terminal device 100 ends the communication in the INACTIVE state, the terminal device 100 transitions from the INACTIVE state to the IDLE state (T2). Note that the INACTIVE state is, for example, a state in which an RRC connection is not established (not wirelessly connected), and thus power consumption is lower than that in the CONNECTED state. Therefore, the terminal device 100 may maintain the INACTIVE state without transitioning to the IDLE state even when communication is completed.

Further, when a large amount of data communication is performed with the first base station apparatus 200, the INACTIVE state is changed to the CONNECTED state (T3). On the other hand, when a large amount of data communication with the first base station device 200 is completed, the terminal device 100 transitions from the CONNECTED state to the INACTIVE state (T3). For example, the terminal device 100 may determine which of the INACTIVE state and the CONNECTED state is changed according to the amount of data to be communicated.

In addition, the state transition of the terminal device 100 in the first base station device 200 may not be implemented in all the state transitions in both directions of the transition T2 between the IDLE state and the INACTIVE state and the transition T3 between the INACTIVE state and the CONNECTED state. For example, the terminal device 100 may not include the transition T3 between the INACTIVE state and the CONNECTED state.

Returning to FIG. 1, the terminal device 100 is in an INACTIVE state in the first base station device 200. Then, the terminal device 100 moves to the second base station device 300 due to the movement of the user of the terminal device 100 or the deterioration of surrounding radio waves. Since the second base station apparatus 300 does not support the INACTIVE state, the terminal apparatus 100 cannot move to the second base station apparatus 300 while maintaining the INACTIVE state.

Therefore, in the first embodiment, the terminal device 100 determines the state after movement. Then, the first base station apparatus 200 that is the movement source sends a UE (User Equipment) context (hereinafter sometimes referred to as a context) of the terminal apparatus 100 that includes position information to the second base station apparatus 300 that is the movement destination. Send. The second base station apparatus 300 that is the movement destination stores the received context in the internal memory, so that the context is not acquired from the terminal apparatus 100 after the movement.

<Configuration example of first base station device>
FIG. 3 is a diagram illustrating a configuration example of the first base station apparatus 200. The first base station apparatus 200 includes a CPU (Central Processing Unit) 210, a storage 220, a memory 230 such as a DRAM (Dynamic Random Access Memory), a NIC (Network Interface Card) 240, and an RF (Radio Frequency) circuit 250.

The storage 220 is an auxiliary storage device such as a flash memory, an HDD (Hard Disk Drive), or an SSD (Solid State Drive) that stores programs and data. The storage 220 stores a communication control program 221, a terminal movement management program 222, and a terminal context information table 223.

The terminal context information table 223 is a UE context of the first base station apparatus 200 and the terminal apparatus 100 in the IDLE state, INACTIVE state, or CONNECTED state (hereinafter, referred to as the terminal apparatus 100 under the first base station apparatus 200). It is a table which memorize | stores (context information) for every terminal device.

The UE context is, for example, information related to a communication path with a network through which the terminal device 100 communicates, and includes information related to a bearer set for the terminal device 100, setting information related to radio measurement of the terminal device 100, and the like. included. Further, the UE context includes, for example, PCI (which is an identifier for uniquely identifying the terminal device 100 in the first base station device 200 and the second base station device 300 (hereinafter also referred to as a base station device). Physical-Cell Identifier), C-RNTI (Cell-Radio Network-Temporary Identifier), and the like. Further, the UE context may include location information of the terminal device 100.

The memory 230 is an area for loading a program stored in the storage 220. The memory 230 is also used as an area where the program stores data.

The NIC 240 is a network interface that is connected to an external network via another base station device or the CR-CN 400. The first base station apparatus 200 relays communication of the terminal apparatus 100 by transmitting and receiving packets to and from other communication apparatuses and external networks via the NIC 240.

The RF circuit 250 is a device that is wirelessly connected to the terminal device 100. For example, the RF circuit 250 includes an antenna, and transmits and receives signals (radio waves) to and from the terminal device 100 that is wirelessly connected, thereby realizing transmission and reception of packets including data with the terminal device 100.

The CPU 210 performs a communication control process by executing the communication control program 221. The communication control process is a process for relaying communication performed by the terminal device 100. In the communication control process, the first base station apparatus 200 transmits, for example, a packet received from the terminal apparatus 100 to the packet transmission destination. Further, in the communication control process, for example, when receiving a packet addressed to the terminal device 100, the first base station device 200 transmits the received packet to the terminal device 100.

The CPU 210 executes the terminal movement management program 222 to construct a reception unit and a transmission unit and perform terminal movement management processing. The terminal movement management process is a process for performing movement management of the terminal apparatus 100 under the control of the first base station apparatus 200. The terminal movement management process includes a movement request reception process as a subroutine.

In addition, the CPU 210 executes a movement request reception module 2221 included in the terminal movement management program 222, thereby constructing a reception unit and a transmission unit and performing a movement request reception process. The movement request reception process is executed when a movement request is received from the terminal apparatus 100, and is a process for transmitting the context of the terminal apparatus 100 to the destination base station apparatus.

<Configuration example of second base station device>
FIG. 4 is a diagram illustrating a configuration example of the second base station apparatus 300. The second base station apparatus 300 includes a CPU 310, a storage 320, a memory 330 such as a DRAM, a NIC 340, and an RF circuit 350.

The storage 320 is an auxiliary storage device such as a flash memory, HDD, or SSD that stores programs and data. The storage 320 stores a communication control program 321, a terminal movement management program 322, and a terminal context information table 323.

The terminal context information table 323 stores the context information of the second base station apparatus 300 and the terminal apparatus 100 in the IDLE state or the CONNECTED state (hereinafter, sometimes referred to as the terminal apparatus 100 under the second base station apparatus 300). It is a table stored for each.

The memory 330 is an area for loading a program stored in the storage 220. The memory 330 is also used as an area where the program stores data.

The NIC 340 is a network interface that is connected to an external network via another base station device or the CR-CN 400.

The RF circuit 350 is a device that is wirelessly connected to the terminal device 100. For example, the RF circuit 350 includes an antenna, and transmits and receives signals (radio waves) to and from the terminal device 100 that is wirelessly connected, thereby realizing transmission and reception of packets including data with the terminal device 100.

The CPU 310 performs communication control processing by executing the communication control program 321. The communication control process is the same process as the communication control process that the first base station apparatus 200 has. The communication control process includes a movement confirmation reception process as a subroutine.

The CPU 310 performs a terminal movement management process by executing the terminal movement management program 322. The terminal movement management process is a process for performing movement management of the terminal apparatus 100 under the control of the second base station apparatus 300. The terminal movement management process includes a movement confirmation reception process as a subroutine.

Further, the CPU 310 performs a movement confirmation reception process by executing a movement confirmation reception module 3221 included in the terminal movement management program 322. The movement confirmation reception process is executed when a movement confirmation is received from the source base station apparatus, and the movement of the terminal apparatus 100 is permitted according to the processing load of the own base station apparatus, the number of subordinate terminal apparatuses, and the like. This is a process for determining whether or not. Further, in the movement confirmation reception process, the second base station device 300 stores the received context of the terminal device 100 in the internal table (terminal context information table 323) when permitting the movement of the terminal device 100.

<Configuration example of terminal device>
FIG. 5 is a diagram illustrating a configuration example of the terminal device 100. The terminal device 100 includes a CPU 110, a storage 120, a memory 130 such as a DRAM, and an RF circuit 150.

The storage 120 is an auxiliary storage device such as a flash memory, HDD, or SSD that stores programs and data. The storage 120 stores a communication program 121 and a quality monitoring program 122.

The CPU 110 performs communication processing by executing the communication program 121. The communication process is a process of communicating with an external network or another communication apparatus via the base station apparatus 200. In the communication processing, for example, the terminal device 100 transmits a packet to the communication device of the communication partner via the base station device. In the communication process, the terminal device 100 receives a packet from the communication device of the communication partner via the base station device, for example.

The CPU 110 executes the quality monitoring program 122 to construct a determination unit and a destination state transmission unit, and perform quality monitoring processing. The quality monitoring process is a process for measuring and monitoring the reception quality of radio waves received from the base station apparatus, such as received power and FER (Frame Err Rate). For example, when the reception quality is equal to or lower than a predetermined value (when quality degradation occurs), the terminal device 100 transmits a movement request for requesting movement to another base station device to the communicating base station device. . Also, the terminal device 100 transmits, for example, periodically measured reception quality to the communicating base station device. Note that the reception quality periodically transmitted may be included in the movement request.

Further, the CPU 110 executes the movement request transmission module 1221 included in the quality monitoring program 122 to construct a movement destination state transmission unit and perform movement request transmission processing. The movement request transmission process is a process of transmitting a movement request to the base station apparatus with which it communicates periodically or when quality degradation occurs.

Further, the CPU 110 executes a designated state determination module 1222 included in the quality monitoring program 122 to construct a determination unit and perform a designated state determination process. In the designated state determination process, when the terminal apparatus 100 transmits a movement request from the first base station apparatus 200 to the second base station apparatus 300, the state at the movement destination (hereinafter sometimes referred to as a designated state) is determined. It is processing to do. In the specified state determination process, the terminal device 100 determines (determines) the specified state according to, for example, the characteristics of communication performed by the own device, the surrounding radio wave environment, and the like.

<Terminal movement process>
FIG. 6 is a diagram illustrating an example of a sequence of terminal movement processing in the wireless communication system 10. The terminal device 100 is in the INACTIVE state with the first base station device 200 (S101), and “Y” (for example, a number), which is a Resume ID for identifying the terminal device 100 in the INACTIVE state, is assigned from the first base station device 200. ing. Then, for example, the terminal device 100 detects the occurrence of quality degradation of the signal received from the first base station device 200 (the radio quality is less than the reference value), and requests movement to the second base station device 300. A movement request is transmitted to the first base station apparatus 200 (S102). The movement request is, for example, a message including the identifier of the destination base station apparatus (second base station apparatus 300), the specified state, and the Resume ID. In the sixth, the movement request S102 includes the identifier “300” of the second base station apparatus 300, the specified state “IDLE”, and the Resume ID “Y”.

1st base station apparatus 200 will perform a movement request reception process, if the movement request is received from the terminal device 100 (S103).

FIG. 7 is a diagram illustrating an example of a process flowchart of the movement request reception process S103. The first base station apparatus 200 generates a movement confirmation including the context corresponding to the ResumeID included in the movement request (that is, corresponding to the terminal apparatus 100) and the specified state included in the movement request (S103-1). The movement confirmation is a message for confirming whether or not the second base station apparatus 300 that is the movement destination is permitted to move the terminal apparatus 100. The 1st base station apparatus 200 extracts the context corresponding to ResumeID from a terminal context information table.

The first base station apparatus 200 transmits the generated movement confirmation to the destination base station apparatus (S103-2). Then, the first base station apparatus 200 waits to receive the movement confirmation result from the movement-destination base station apparatus (No in S103-3). When receiving the movement confirmation result (Yes in S103-3), the first base station apparatus 200 confirms the movement confirmation result (S103-4).

If the movement confirmation result is OK (Yes in S103-4), the first base station apparatus 200 determines that the movement of the terminal apparatus 100 is permitted, and deletes the context corresponding to the ResumeID of the movement request (S103- 5) A movement response (OK) is transmitted to the terminal device 100 (S103-6). The first base station apparatus 200 deletes the context corresponding to the ResumeID of the movement request by transmitting the context to the second base station apparatus 300 that is the movement destination, so that the terminal apparatus 100 is the second base station apparatus that is the movement destination. This is to move to 300. That is, the terminal apparatus 100 moves under the control of the second base station apparatus 300, not under the control of the first base station apparatus 200. The movement response (OK) is a message that permits the terminal apparatus 100 to move to the destination base station apparatus included in the movement request transmitted by the terminal apparatus 100.

On the other hand, if the movement confirmation result is not OK (No in S103-4), first base station apparatus 200 determines that movement of terminal apparatus 100 is not permitted, and transmits a movement response (NG) to terminal apparatus 100 ( S103-7). The movement response (NG) is a message indicating that the terminal apparatus 100 is not permitted to move to the destination base station apparatus included in the movement request transmitted by the terminal apparatus 100. The first base station apparatus 200 does not delete the context of the terminal apparatus 100 because the terminal apparatus 100 does not move to the destination base station apparatus.

Returning to the sequence of FIG. 6, the first base station apparatus 200 transmits a movement confirmation including the context and the designated state to the second base station apparatus 300 in the movement request reception process S103 (S104, S103-2 of FIG. 7). . When the second base station apparatus 300 receives the movement confirmation, the second base station apparatus 300 performs a movement confirmation reception process (S105).

FIG. 8 is a diagram illustrating an example of a process flowchart of the movement confirmation reception process S105. The second base station apparatus 300 confirms whether the designated state included in the received movement confirmation is CONNECTED (S105-1).

When the specified state is the CONNECTED state (Yes in S105-1), the second base station device 300 determines whether or not the number of terminal devices 100 in the CONNECTED state can be increased (S105-2). For example, when the base station apparatus is in a congested state or the processing load is a predetermined value or more, the second base station apparatus 300 determines that the terminal apparatus 100 in the CONNECTED state cannot be increased any more. .

If the second base station device 300 determines that the number of terminal devices 100 in the CONNECTED state can be increased (Yes in S105-2), the second base station device 300 stores the context included in the movement confirmation in the internal memory (terminal context information table 323). (S105-3), the movement confirmation result (OK) is transmitted to the source base station apparatus (S105-4). The movement confirmation result (OK) is a message that permits the terminal apparatus 100 to move to the destination base station apparatus. The second base station apparatus 300 stores the context of the moving terminal apparatus 100 in the internal memory, so that processing (transmission / reception of a predetermined message) with the terminal apparatus 100 for acquiring the context can be omitted. .

On the other hand, if the second base station apparatus 300 determines that the number of connected terminal apparatuses 100 cannot be increased (No in S105-2), the second base station apparatus 300 transmits a movement confirmation result (NG) to the movement source base station apparatus (S105). −5) End the processing. The movement confirmation result (NG) is a message that does not permit the terminal apparatus 100 to move to the movement destination base station apparatus.

Returning to the sequence of FIG. 6, in the movement confirmation reception process S105, the second base station apparatus 300 stores the context (S106, S105-3 of FIG. 8), and transmits the movement confirmation result (OK) (S107, FIG. 8 S105-4).

When the first base station apparatus 200 receives the movement confirmation result (OK) in the movement request reception process S103, the first base station apparatus 200 deletes the context of the terminal apparatus 100 (S108, S103-5 in FIG. 7) and sends a movement response (OK). The data is transmitted to the terminal device 100 (S109, S103-6 in FIG. 7).

Upon receiving the movement response (OK), the terminal apparatus 100-1 enters the IDLE state that is the designated state with the second base station apparatus 300 that is the movement destination (S110). Here, the terminal device 100-1 does not perform a process of establishing a context between the terminal device 100 and the second base station device 300 that is the movement destination or a TAU procedure. This is because the second base station apparatus 300 that is the movement destination stores the context of the terminal apparatus 100, so that it is not necessary to execute a process for establishing a context or a TAU procedure.

In the first embodiment, when the terminal device 100 in the INACTIVE state moves to the second base station device 300 that does not correspond to the INACTIVE state, the destination state is specified. Thereby, the terminal device 100 can make a transition to an appropriate state at the destination base station device.

In the first embodiment, when the terminal device 100 moves, the first base station device 200 that is the movement source takes over the context of the terminal device 100 to the second base station device 300 that is the movement destination. Thereby, the context establishment procedure and TAU procedure after the movement of the terminal device 100 can be omitted. Therefore, it is possible to realize power saving of the terminal device 100 and a reduction in radio resource usage by executing the procedure.

<First Modification>
In the first modified example, a process in which the terminal device 100 changes the CONNECTED state to the designated state and transitions to the connected state will be described.

FIG. 9 is a diagram showing an example of a sequence of terminal movement processing when CONNECTED is designated as the designated state by the terminal device 100. The terminal device 100 is in an INACTIVE state with the first base station device 200 (S101). The terminal device 100 transmits a movement request to the first base station device 200 (S201). The movement request includes a designated state “CONNECTED”. When receiving the movement request from the terminal apparatus 100, the first base station apparatus 200 performs a movement request reception process (S103).

In the movement request reception process S103, the first base station apparatus 200 transmits a movement confirmation including the context and the specified state (CONNECTED) to the second base station apparatus 300 (S202, S103-2 in FIG. 7). When the second base station apparatus 300 receives the movement confirmation, the second base station apparatus 300 performs a movement confirmation reception process (S105).

In the movement confirmation reception process S105, the second base station apparatus 300 determines whether or not the terminal apparatus 100 can be subordinate to the own apparatus (increase in the number of terminal apparatuses 100 in the CONNECTED state is possible) (FIG. 8). S105-2). If the second base station apparatus 300 determines that the terminal apparatus 100 can be subordinated (Yes in S105-2 in FIG. 8), the second base station apparatus 300 stores the context (S106, S105-3 in FIG. 8), and the movement confirmation result (OK) is transmitted (S107, S105-4 in FIG. 8).

Upon receiving the movement response (OK), the terminal apparatus 100-1 performs a simple attach procedure (omission procedure) with the second base station apparatus 300 that is the movement destination (S203).

The simple attach procedure is, for example, a procedure in which some procedures are omitted from the handover procedure in which the terminal device 100 moves in the base station device while maintaining the CONNECTED state. The procedure to be omitted is a partial procedure for acquiring (or establishing) information included in the context.

The second base station apparatus 300 can omit, for example, an IMSI (International Mobile Subscriber Identity) request (acquisition) procedure. The IMSI is an identifier that identifies the contractor of the terminal device 100. The IMSI request procedure is, for example, a procedure in which the second base station apparatus 300 transmits an IMSI request to the terminal apparatus 100, and the terminal apparatus 100 transmits an IMSI response to the second base station apparatus 300.

Also, the second base station apparatus 300 can omit, for example, a procedure for acquiring information related to authentication and security. The authentication request procedure is, for example, a procedure in which the second base station device 300 transmits an authentication request to the terminal device 100, and the terminal device 100 transmits an authentication response to the second base station device 300. The security request procedure is a procedure in which, for example, the second base station device 300 transmits a security request to the terminal device 100, and the terminal device 100 transmits a security response to the second base station device 300. Note that the encryption instruction procedure in the RRC (Radio Resource Control) layer may be omitted.

Furthermore, the second base station apparatus 300 can omit a procedure for establishing (acquiring) information on a bearer between the MME and the S-GW, for example. The bearer information is information relating to a session between the second base station apparatus 300 and the NR-CN 400, for example. When the second base station apparatus 300 receives the context from the first base station apparatus 200, the second base station apparatus 300 obtains information related to the session between the first base station apparatus 200 and the NR-CN 400 and the NR-CN 400 and the NR-CN 400. -Change to information about sessions between CNs 400 and store in internal memory.

Furthermore, the second base station apparatus 300 can omit the procedure for acquiring information related to the capability of the terminal apparatus 100. Capability is information regarding the capability and version of the terminal device 100. The Capability acquisition procedure is, for example, a procedure in which the second base station apparatus 300 transmits a Capability request to the terminal apparatus 100, and the terminal apparatus 100 transmits a Capability response to the second base station apparatus 300.

The terminal device 100 performs a simple attach procedure and enters the CONNECTED state with the second base station device 300 (S204).

In the first modification of the first embodiment, the terminal device 100 transitions to the CONNECTED state by performing a simple attach procedure in the destination base station device. As a result, some procedures can be omitted from the normal handover procedure, and power saving of the terminal device 100 and a reduction in the amount of radio resources used can be realized.

<Second Modification>
In the second modification, a process when the terminal device 100 sets the CONNECTED state to the designated state and the destination base station device does not permit the movement will be described.

FIG. 10 is a diagram illustrating an example of a sequence of terminal movement processing when CONNECTED is designated as the designated state by the terminal device 100. The terminal device 100 is in an INACTIVE state with the first base station device 200 (S101). The terminal apparatus 100 transmits a movement request for requesting movement to the second base station apparatus 300 to the first base station apparatus 200 (S201). The movement request includes a designated state “CONNECTED”.

In the movement confirmation reception process S105, the second base station apparatus 300 determines whether or not the terminal apparatus 100 can be subordinate to the own apparatus (S105-2 in FIG. 8). For example, the second base station apparatus 300 determines that the terminal apparatus 100 cannot be subordinated based on the occurrence of congestion or an increase in processing load (No in S105-2 in FIG. 8). The second base station apparatus 300 transmits a movement confirmation result (NG) (S301, S105-5 in FIG. 8).

When the first base station apparatus 200 receives the movement confirmation result (NG) in the movement request reception process S103, the first base station apparatus 200 transmits a movement response (NG) to the terminal apparatus 100 (S302, S103-7 in FIG. 7). At this time, the first base station apparatus 200 does not delete the context of the terminal apparatus 100.

When receiving the movement response (NG), the terminal apparatus 100-1 maintains the INACTIVE state with the movement-source first base station apparatus 200. Alternatively, the terminal device 100 may transition to the IDLE state with the first base station device 200, for example, when reception quality (wireless quality) degradation occurs.

In the second modification of the first embodiment, the terminal device 100 does not move to the destination base station device, for example, when congestion occurs in the destination base station device. And the terminal device 100 maintains an INACTIVE state, for example. Thereby, the terminal device 100 can prevent movement to a base station device that cannot secure a necessary communication amount, and can maintain an INACTIVE state with the source base station device.

[Second Embodiment]
In the second embodiment, a specified state determination process in the terminal device 100 will be described.

<Specified state determination processing>
FIG. 11 is a diagram illustrating an example of a sequence for performing a designated state determination process when the terminal apparatus 100 moves between base station apparatuses. The terminal device 100 determines the designated state included in the movement request (S402) transmitted to the first base station device 200 in the INACTIVE state (S101) by the designated state determination process (S401).

FIG. 12 is a diagram illustrating an example of a process flowchart of the designated state determination process S401. In the designated state determination process S401, the terminal device 100 determines the designated state based on the communication data amount in the past predetermined time.

The terminal device 100 acquires the amount of communication data in the past predetermined time (S401-1). For example, the terminal device 100 stores the communication data amount in the past predetermined time in the internal memory.

When the acquired communication data amount for a predetermined time is less than the threshold (No in S401-2), the terminal device 100 determines the designated state as the IDLE state (S401-3). On the other hand, when the acquired communication data amount for a predetermined time is equal to or larger than the threshold (Yes in S401-2), the designated state is determined as the CONNECTED state (S401-4).

The terminal device 100 transmits a movement request including the determined designation state, ResumeID, and the identifier of the movement-destination base station apparatus to the movement-source base station apparatus (S401-5).

Thereby, the terminal device 100 can transition to the IDLE state when the communication data amount is small, and transition to the CONNECTED state when the communication data amount is large, and can transition to an appropriate state according to the communication data amount.

When the terminal device 100 is an IoT terminal, the communication frequency and the communication data amount may be determined in advance. In such a case, when the terminal apparatus 100 moves the base station apparatus in the INACTIVE state and the destination base station apparatus does not support the INACTIVE state, the terminal apparatus 100 indicates the transition destination state in the storage or internal memory. You may remember it. In this case, the terminal device 100 reads the stored specified state and includes it in the movement request in the specified state determination process.

[Third embodiment]
In the third embodiment, a case will be described in which terminal device 100 transmits a movement request including a specified parameter.

<Terminal movement process>
FIG. 13 is a diagram illustrating an example of a sequence of terminal movement processing in the wireless communication system 10. The terminal device 100 is in an INACTIVE state with the first base station device 200 (S101). The terminal device 100 determines the designated state included in the movement request (S502) transmitted to the first base station device 200 in the INACTIVE state (S101) in the designated state determination process (S501).

FIG. 14 is a diagram illustrating an example of a process flowchart of the designated state determination process S501. Processing S401-1 to S401-1 in FIG. 14 is the same as processing S401-1 to S401-1 in FIG.

When the terminal device 100 determines that the specified state is CONNECTED (S401-4), the terminal device 100 acquires a specified parameter (S501-1). The designated parameter is stored in, for example, a storage or a memory of the terminal device 100. Then, when the designated state is CONNECTED, the terminal apparatus 100 includes the designated parameter in the movement request and transmits the movement request to the movement-source base station apparatus (S501-2). Further, the designated parameter may be determined by the characteristics of the terminal device 100. The characteristics are, for example, communication frequency, communication data amount, presence / absence of movement, and the like, and are characteristics of the terminal device 100 according to the service contents that the terminal device 100 enjoys or provides in communication.

FIG. 15 is a diagram showing an example of a designated parameter list. For example, the terminal device 100 designates a time interval of DRX (Discontinuous Reception). When the terminal device 100 is a terminal device dedicated to transmission, a long time (or no reception) is specified for the reception interval.

Also, the terminal device 100 specifies ue-InactiveTime. The second base station apparatus monitors the non-communication time during which communication with the terminal apparatus 100 is not performed, and if no communication continues for the time specified by ue-InactiveTime, an RRC connection (wireless session) with the terminal apparatus 100 is established. Monitor the communication to be released (released). For example, when the terminal device 100 is an IoT terminal that performs communication only once a month and has a low communication frequency, the terminal device 100 is specified to release an RRC connection in a short time.

Furthermore, the terminal device 100 designates information related to ReportConfigEUTRA. ReportConfigEUTRA is information in which a transmission period for transmitting a quality report including a measurement content of a reception quality and a measurement result is set. When the terminal device 100 is a terminal device that does not move, it is unlikely that a change in reception quality will occur, so it is specified not to measure.

Furthermore, the terminal device 100 designates information related to CQI (Channel Quality Indicator) -Report Config. CQI-ReportConfig is information in which a CQI (quality report) report cycle (transmission cycle) and measurement contents are set. If the terminal device 100 is a terminal device that does not move, it is unlikely that a change in CQI will occur, so it is specified not to measure (or report).

Returning to the sequence of FIG. 13, in the designated state determination process S <b> 501, the terminal device 100 sets the designated state to “CONNECTED” and the designated parameter to “Z” (Z is a combination of parameters shown in FIG. 15 or one). Is transmitted (S502, S501-2 in FIG. 14). When receiving the movement request from the terminal apparatus 100, the first base station apparatus 200 performs a movement request reception process (S503).

FIG. 16 is a diagram illustrating an example of a process flowchart of the movement request reception process S503. Processing S103-2 to 7 in FIG. 16 is the same as processing S103-2 to 7 in FIG. The first base station apparatus 200 generates a movement confirmation including the specified parameter included in the movement request when the movement request includes the specified parameter in addition to the context corresponding to the ResumeID and the specified state (S503-1). .

Returning to the sequence of FIG. 13, in the movement request reception process S503, the first base station apparatus 200 transmits a movement confirmation including the designated parameter to the second base station apparatus 300 (S504, S103-2 of FIG. 16). When receiving the movement confirmation, the second base station apparatus 300 performs a movement confirmation reception process (S505).

FIG. 17 is a diagram illustrating an example of a process flowchart of the movement confirmation reception process S505. Processes S105-1 to S105-1 in FIG. 17 are the same as the processes S105-1 to S105-1 in FIG. The second base station apparatus 300 stores the designated parameter in the internal memory in addition to the movement confirmation context (S105-4) (S505-1).

Returning to the sequence of FIG. 13, the second base station apparatus 300 stores the context and the designated parameter in the internal memory in the movement confirmation reception process S505 (S506, S105-4 and S505-1 in FIG. 17). Then, the second base station apparatus 300 transmits the movement confirmation result (OK) to the first base station apparatus 200 in the movement confirmation reception process S505 (S107). Hereinafter, the processes S108, S109, S203, and S204 of the sequence of FIG. 13 are the same as the processes S108, S109, S203, and S204 of the sequence of FIG.

In addition, the terminal device 100 performs processing according to the designated parameter in the CONNECTED state with the second base station device 300.

In the third embodiment, the designated parameter is shared between the terminal apparatus 100 and the second base station apparatus 300 that is the movement destination. Thereby, the terminal device 100 can implement | achieve further power saving.

[Fourth embodiment]
In the fourth embodiment, the terminal device 100 periodically transmits a movement request. The first base station apparatus 200 determines the movement of the terminal apparatus 100.

<Terminal movement process>
FIG. 18 is a diagram illustrating an example of a sequence of terminal movement processing in the wireless communication system 10. The terminal device 100 is in an INACTIVE state with the first base station device 200 (S101). For example, the terminal device 100 periodically transmits a movement request to the first base station device 200 (S601).

1st base station apparatus 200 will perform a movement request reception process, if a movement request is received from the terminal device 100 (S602).

FIG. 19 is a diagram illustrating an example of a process flowchart of the movement request reception process S602. The first base station apparatus 200 determines whether or not a movement opportunity of the terminal apparatus 100 has occurred (S602-1). For example, the first base station apparatus 200 determines the movement trigger of the terminal apparatus 100 based on the reception quality measurement result by the terminal apparatus 100 included in the movement request. Moreover, the 1st base station apparatus 200 determines the movement opportunity of the terminal device 100 based on the reception quality of the signal received from the terminal device 100, for example. Alternatively, the first base station apparatus 200 may determine the movement opportunity of the terminal apparatus 100 based on both the reception quality of the terminal apparatus 100 and the reception quality of the first base station apparatus 200.

If the first base station apparatus 200 determines that the movement trigger of the terminal apparatus 100 has occurred (S602-Yes), the first base station apparatus 200 performs processes S103-1 to S103-7. Processes S103-1 to S103-7 in FIG. 19 are the same processes as processes S103-1 to S103-7 in FIG.

On the other hand, if the first base station apparatus 200 determines that there is no movement opportunity of the terminal apparatus 100 (S602-No), the first base station apparatus 200 ends the process.

Returning to the sequence of FIG. 18, the first base station apparatus 200 determines in the movement request reception process S602 that the movement trigger of the terminal apparatus 100 has not occurred (Yes in S602-1 of FIG. 19), and ends the process. To do.

Then, the wireless quality deteriorates (wireless quality becomes less than the reference value) from a certain timing (S604). At this time, the first base station apparatus 200 receives the movement request (S605) and performs a movement request reception process (S602).

In the movement request reception process S602, the first base station apparatus 200 determines that a movement opportunity of the terminal apparatus 100 due to radio quality degradation has occurred (Yes in S602-1 in FIG. 19), and performs the movement confirmation for the second time. It transmits to the base station apparatus 300 (S606, S103-2 in FIG. 19). Thereafter, the processes S105 to 110 in FIG. 18 are the same as the processes S105 to 110 in FIG.

In the fourth embodiment, the terminal device 100 specifies a parameter to be used at the destination in addition to the state at the destination. Thereby, the terminal device 100 can perform more suitable communication in the movement-destination base station device.

[Fifth embodiment]
In the fifth embodiment, the terminal device 100 sets an intermediate state different from the IDLE state and the CONNECTED state as the designated state. The intermediate state is, for example, a state that approximates (or is equivalent to) the INACTIVE state in the first communication scheme, and is a state that corresponds to the second base station apparatus 300 in the second communication scheme.

<Terminal movement process>
FIG. 20 is a diagram illustrating an example of a sequence of terminal movement processing in the wireless communication system 10. The terminal device 100 is in an INACTIVE state with the first base station device 200 (S101). The terminal device 100 transmits a movement request with the designated state set to the intermediate state (NEW in FIG. 20) to the first base station device 200 (S701). When receiving the movement request from the terminal apparatus 100, the first base station apparatus 200 performs a movement request reception process (S103).

In the movement request reception process S103, the first base station apparatus 200 transmits a movement confirmation including the context and the specified state (intermediate state) to the second base station apparatus 300 (S702, S103-2 in FIG. 7). When the second base station apparatus 300 receives the movement confirmation, the second base station apparatus 300 performs a movement confirmation reception process (S105). Thereafter, the processes S105 to 109 in FIG. 20 are the same as the processes S105 to 109 in FIG.

The terminal device 100 receives the movement response (OK) (S109), and transitions to an intermediate state with the second base station device 300 (S703).

For example, it is assumed that the first communication method is a method conforming to 5G and the second communication method is a communication conforming to 4G. The INACTIVE state proposed in 5G is a state that does not correspond in 4G. Therefore, in 4G, an intermediate state that approximates (or is the same as) the 5G INACTIVE state is defined, and the second base station device 300 corresponds to the intermediate state. At 300, it is possible to transition to an intermediate state that approximates (or is the same as) the INACTIVE state. For example, if a wireless session (for example, an RRC session) between the terminal device 100 and the first base station device 200 is not established in the INACTIVE state, a wireless session with the second base station device 300 is not established. In S702, the TAU procedure and the wireless session establishment process can be omitted.

DESCRIPTION OF SYMBOLS 10 ... Wireless communication system 100 ... Terminal device 110 ... CPU
DESCRIPTION OF SYMBOLS 120 ... Storage 121 ... Communication program 122 ... Quality monitoring program 1221 ... Movement request transmission module 1222 ... Designated state determination module 130 ... Memory 150 ... RF circuit 200 ... 1st base station apparatus 210 ... CPU
220 ... Storage 221 ... Communication control program 222 ... Terminal movement management program 2221 ... Movement request receiving module 223 ... Terminal context information table 230 ... Memory 240 ... NIC
250 ... RF circuit 300 ... second base station apparatus 310 ... CPU
320 ... Storage 321 ... Communication control program 322 ... Terminal movement management program 3221 ... Movement confirmation receiving module 323 ... Terminal context information table 330 ... Memory 340 ... NIC
350 ... RF circuit 400 ... NR-CN

Claims

A terminal device, a base station device of a first communication method, and another base station device of a second communication method different from the first communication method, wherein the base station device and the other base station device are the terminals The base station apparatus in a wireless communication system that relays communication of the apparatus,
The destination state indicating the state at the destination of the terminal device is received from the terminal device in the first state, which is a state of the terminal device with respect to the base station device and is not supported by the second communication method. A receiver,
A base station apparatus comprising: a transmission unit that transmits context information regarding the destination state and a communication path of the terminal apparatus to the other base station apparatus when the terminal apparatus moves to the other base station apparatus.
The first state is a state in which the base station device holds a session related to communication of the terminal device between a control device that controls the base station device and the other base station device and the base station device. Item 4. The base station apparatus according to Item 1.
The base station apparatus according to claim 2, wherein the context information includes information related to the session.
The base station apparatus according to claim 2, wherein the context information includes information regarding a position of the terminal apparatus.
The base station apparatus according to claim 1, wherein the first state is an INACTIVE state.
The transmitter further includes:
A movement confirmation for confirming whether or not to allow the terminal apparatus to move to the other base station apparatus is transmitted to the other base station apparatus;
Receiving the result of the movement confirmation from the other base station device;
Sending the received movement confirmation result to the terminal device,
When the movement of the terminal device is permitted in the result of the movement confirmation, the context information of the terminal device is deleted.
The base station apparatus according to claim 1.
The base station apparatus according to claim 1, wherein the transmission unit determines that the terminal apparatus moves to the other base station apparatus when radio quality between the terminal apparatus and the base station apparatus is less than a reference value. .
When the transmission unit receives the destination state transmitted from the terminal device when the wireless quality between the terminal device and the base station device is less than a reference value, the terminal device receives the other base station. The base station apparatus according to claim 1, wherein the base station apparatus is determined to move to the apparatus.
The receiving unit further receives, from the terminal device, parameters used by the terminal device at a destination,
The base station apparatus according to claim 1, wherein the transmission unit further transmits the parameter to the other base station apparatus.
The base station apparatus according to claim 9, wherein the parameter includes a reception interval of intermittent reception performed by the terminal apparatus.
The terminal device measures radio quality, performs a quality report to transmit the measurement result to the other base station device,
The base station apparatus according to claim 9, wherein the parameter includes one or both of the measurement content to be measured and the transmission cycle of the quality report.
The other base station device monitors communication with the terminal device, and performs communication monitoring to release a wireless session with the terminal device when a time during which the communication is not performed is a first time or more,
The base station apparatus according to claim 9, wherein the parameter is the first time in the communication monitoring.
A terminal device, a base station device of a first communication method, and another base station device of a second communication method different from the first communication method, wherein the base station device and the other base station device are the terminals A terminal device in a wireless communication system that relays communication of a device,
When the terminal apparatus is in a first state that is a state with respect to the base station apparatus and is not supported by the second communication method, a destination state indicating a state at a destination of the terminal apparatus is determined. A decision unit;
The terminal device which has a movement destination state transmission part which transmits the said movement destination state to the said base station apparatus.
The terminal device according to claim 13, wherein the determination unit determines the destination state based on a communication data amount of the terminal device at a predetermined time.
The determining unit further determines a parameter used by the terminal device at a destination,
The terminal apparatus according to claim 13, wherein the destination state transmission unit transmits the determined parameter to the base station apparatus.
The terminal device according to claim 15, wherein the determination unit determines the parameter according to characteristics of the terminal device.
A terminal device;
A base station device of a first communication method for relaying communication of the terminal device;
Having another base station device of the second communication method different from the first communication method of relaying communication of the terminal device;
When the terminal apparatus is in a first state that is a state of the terminal apparatus with respect to the base station apparatus and is not supported by the second communication method, a movement destination indicating a state at a movement destination of the terminal apparatus Sending the state to the base station device;
When the terminal device moves to the other base station device, the base station device transmits the received destination state and context information regarding the communication path of the terminal device to the other base station device,
The other base station apparatus stores the received context information of the terminal apparatus.
When the destination state is the second state,
The radio communication system according to claim 17, wherein the another base station apparatus performs an abbreviated procedure in which an acquisition procedure of information included in the context information is omitted, and causes the terminal apparatus to transition to the second state.
The wireless communication system according to claim 18, wherein the second state is an IDLE state in which a wireless session is not established between the terminal device and the other base station device.
The wireless communication system according to claim 18, wherein the second state is a CONNECTED state in which communication of a predetermined data amount or more can be performed between the terminal device and the other base station device.
A terminal device, a base station device of a first communication method, and another base station device of a second communication method different from the first communication method, wherein the base station device and the other base station device are the terminals A terminal moving method in the base station apparatus in a wireless communication system that relays communication of the apparatus,
A destination state indicating a state at a destination of the terminal device is received from a terminal device in the first state, which is a state of the terminal device with respect to the base station device and is not supported by the second communication method. ,
A terminal moving method, wherein when the terminal device moves to the other base station device, context information related to the destination state and a communication path of the terminal device is transmitted to the other base station device.