WO2020031317A1

WO2020031317A1 - Base station apparatus, terminal apparatus, and communication system

Info

Publication number: WO2020031317A1
Application number: PCT/JP2018/029859
Authority: WO
Inventors: 長谷川哲哉; 平田昂
Original assignee: 富士通株式会社
Priority date: 2018-08-09
Filing date: 2018-08-09
Publication date: 2020-02-13
Also published as: JPWO2020031317A1; JP7181479B2

Abstract

A base station apparatus, in a communication system including a terminal apparatus, base station apparatuses capable of communicating with the terminal apparatus and a control apparatus, comprises: a receiving unit that receives, from the control apparatus, control information related to the release of a first type of context; a first management unit that releases the first type of context; and a second management unit that, if having a second type of context, releases the second type of context and notifies another base station apparatus of control information related to the release of the second type of context.

Description

Base station device, terminal device, and communication system

<< The present invention relates to a base station device, a terminal device, and a communication system.

In the current network, the traffic of mobile terminals (smartphones and feature phones) occupies most of the network resources. In addition, the traffic used by mobile terminals tends to increase in the future.

On the other hand, in line with the development of IoT (Internet of things) services (for example, monitoring systems for traffic systems, smart meters, devices, and the like), it is required to support services having various requirements. Therefore, in the communication standard of the fifth generation mobile communication (5G or NR (New @ Radio)), in addition to the standard technology of 4G (fourth generation mobile communication) (for example, Non-Patent Documents 1 to 11), There is a need for a technology that achieves high data rates, large capacity, and low delay. Technical studies on the fifth generation communication standard are being conducted by 3GPP working groups (eg, TSG-RAN @ WG1, TSG-RAN @ WG2, etc.) (Non-Patent Documents 12 to 38).

As described above, in order to support a wide variety of services, in 5G, eMBB (Enhanced Mobile Broadband) that realizes high-speed transmission, Massive MTC (Machine Type Communications) that enables simultaneous connection of many IoT devices, And high reliability and low delay transmission. It is assumed that many use cases classified as URLLC (Ultra-Reliable and Low Low Latency Communication) will be supported.

In $ 5G, RRC (Radio Resource Control) state is defined as RRC_INACTIVE state (hereinafter abbreviated as INACTIVE) in addition to IDLE state and RRC_CONNECTED state (hereinafter abbreviated as CONNECTED) (Non-Patent Document 20).

Line setting information (context) used for communication so that the terminal device in the inactive state and the base station device that has shifted the terminal device to the inactive state can be immediately shifted to the communication state (RRC_CONNECTED state (hereinafter abbreviated as CONNECTEDED)). Holding each other.

技術 Techniques related to communication are described in the following patent documents and non-patent documents.

International Publication No. WO2018 / 030259 International Publication No. WO2018 / 062499

However, when the terminal device in the inactive state moves to a cell of another base station device, for example, even if the base station device before the movement transits from the inactive state to the IDLE state, the terminal device retains the context, Maintain the INACTIVE state. As described above, the states of the terminal recognized by the base station apparatus and the terminal recognized by the terminal apparatus may be different from each other.

Therefore, the disclosed technology provides a base station device, a terminal device, and a communication system that perform state transition efficiently.

According to one aspect, a base station device in a communication system including a terminal device, a base station device capable of performing communication with the terminal device, and a control device, wherein a first type context is released from the control device A control unit for receiving control information related to the first type context, a first management unit configured to release the first type context, and a control related to releasing the second type context when the second type context is provided. A second management unit that notifies information to another base station apparatus.

(4) The disclosed technology can efficiently perform state transition.

FIG. 1 is a diagram illustrating a configuration example of a communication system 10. FIG. 2 is a diagram illustrating a configuration example of the communication system 10. FIG. 3 is a diagram illustrating an example of a sequence (procedure) when the terminal device 100 in the inactive state transmits a call. FIG. 4 is a diagram illustrating an example of a sequence (procedure) when an incoming call is received by the terminal device 100 in the INACTIVE state. FIG. 5 is a diagram illustrating an example of a sequence (procedure) of transition from the inactive state to the IDLE state according to the first embodiment. FIG. 6 is a diagram illustrating a configuration example of the base station apparatus 200. FIG. 7 is a diagram illustrating a configuration example of the terminal device 100. FIG. 8 is a diagram illustrating an example of a sequence (procedure) of transition from the inactive state to the IDLE state according to the second embodiment. FIG. 9 is a diagram illustrating an example of a process flowchart of the UEContextReleaseCommand reception process S103. FIG. 10 is a diagram illustrating an example of a processing flowchart of paging reception processing S107. FIG. 11 is a diagram illustrating an example of a message format of RAN @ Paging. FIG. 12 is a diagram illustrating an example of a Paging message format. FIG. 13 is a diagram illustrating an example of a sequence (procedure) of transition from the inactive state to the IDLE state according to the third embodiment. FIG. 14 is a diagram illustrating an example of a process flowchart of the UEContextReleaseCommand reception process S203. FIG. 15 is a diagram illustrating an example of a processing flowchart of Delete \ UE \ Context \ Request reception processing S206. FIG. 16 is a diagram illustrating an example of a process flowchart of the RRCConnectionResumeRequest reception process S210. FIG. 17 is a diagram illustrating an example of a message format of Delete \ UE \ Context \ Request. FIG. 18 is a diagram illustrating an example of a message format of Delete \ UE \ Context \ Response.

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

<Configuration example of communication system>
FIG. 2 is a diagram illustrating a configuration example of the communication system 10. The communication system 10 includes a terminal device 100, base station devices 200-1 and 200-2, and a control device 300. The communication system 10 is, for example, a communication system compatible with a 5G communication standard.

The terminal device 100 is, for example, a mobile terminal or a computer. The terminal device 100 communicates with, for example, the base station device 200-1, and downloads data and receives provision of a service. Further, the terminal device 100 and the base station devices 200-1 and 200-2 perform communication based on, for example, TCP / IP. Note that the terminal device 100 is assumed to move, and the terminal device 100 before movement may be referred to as a terminal device 100-a, and the terminal device 100 after movement may be referred to as a terminal device 100-b.

The base station devices 200-1 and 200-2 (hereinafter sometimes referred to as the base station device 200) are relay devices that wirelessly connect to the terminal device 100 and transmit and receive packets to and from the terminal device 100. The base station device 200 transmits, for example, a packet received from the terminal device 100 or transmits a received packet addressed to the terminal device 100 to the terminal device 100 to a partner device with which the terminal device 100 communicates. The base station device 200 is, for example, a gNodeB in 5G.

The base station devices 200-1 and 200-2 have a communication area (or cell) indicating an area where wireless communication with the terminal device 100 is possible. The base station device 200-1 has a communication area A200-1 and the base station device 200-2 has a communication area A200-2.

The control device 300 is a device that is connected to the base station device 200 and manages the movement of the terminal device 100. The control device 300 is, for example, an AMF (Access and Mobility management function) in 5G.

The communication system 10 corresponds to the INACTIVE state. Hereinafter, a description will be given of a process performed when the terminal device 100 enters the inactive state in the terminal device 100-a before the movement, and performs the outgoing and incoming calls in the terminal device 100-b after the movement.

FIG. 2 is a diagram illustrating an example of a sequence (procedure) in which the terminal device 100 transitions to the INACTIVE state. The terminal device 100 is in a CONNECTED state in which it is wirelessly connected to the base station device 200-1 and performs communication (S10). As described above, the terminal device 100 can transition to the CONNECTED state by executing a part of the sequence (procedure) when transitioning from the IDLE state to the CONNECTED state. Note that CONNECTED indicates a state in which wireless channel control is performed between the base station device and the terminal device. In other words, it indicates that wireless communication is possible. Furthermore, it is in a state where services such as highly reliable low delay communication and high speed communication are being implemented. On the other hand, the IDLE indicates a state in which wireless channel control is performed between the base station apparatus and the terminal apparatus, and is also a state in which services such as the highly reliable low-delay communication cannot be received. It is also called standby. In other words, it indicates that wireless communication is not possible. Further, the inactive state is a state located between the CONNECTED state and the IDLE state, and a wireless line is not set and wireless communication is impossible, but a service level setting remains, or Is out of service, but the service can be continued. In addition, it can also be called a standby state.

When the base station device 200-1 triggers the terminal device 100 to transition to the INACTIVE state (S11), the base station device 200-1 transmits a message (for example, RRCConnectionReconfiguration) instructing the terminal device 100 to transition to the state (S12), and changes the state to CONNECTED. Instruct to transition from the state to the INACTIVE state.

The trigger for transitioning the terminal device 100 to the inactive state is, for example, when a predetermined time has elapsed since the terminal device 100 transmitted or received the last data packet, or when the control device 300 transitions the terminal device 100 to the inactive state. Is instructed to do so.

The base station apparatus 200-1 holds the AS (Access Stratum) context corresponding to the terminal apparatus 100 when the terminal apparatus 100 transitions to the inactive state (S13).

The AS context is line setting information (Channel setting information or channel configuration) held in the inactive state, and includes, for example, MAC-I, I-RNTI, and information on AS security. In the inactive state (second state), the terminal device 100 and the base station device 200 mutually hold the AS context. In the INACTIVE state, the terminal device 100 and the base station device 200 can transition to the CONNECTED state (first state) in which communication is possible by executing a part of the connection sequence executed in the IDLE state. .

Upon receiving the RRCConnectionReconfiguration (S12), the terminal device 100 retains the AS context (S14) and transits to the INACTIVE state (S15).

FIG. 3 is a diagram showing an example of a sequence at the time of transmission of the terminal device 100 in the inactive state. The terminal device 100 moves from the terminal device 100-a to the position of the terminal device 100-b, and is located within the communication area of the base station device 200-2.

(4) The terminal device 100 is in the INACTIVE state (S20). The terminal device 100 transmits a message (for example, RRCConnectionResumeRequest) requesting resumption of the RRC connection to the base station device 200-2 (S21). The RRCConnectionResumeRequest includes an I-RNTI (Inactive-Radio Network Network Temporary Identifier). The I-RNTI is, for example, an identifier temporarily given to the terminal device when the terminal device 100 transitions to the inactive state. By acquiring the I-RNTI, the base station device 200 can identify the terminal device 100 that is the target of the restart of the RRC connection.

When receiving the RRCConnectionRequestRequest (S21), the base station device 200-2 does not hold the UE context and the AS context of the target terminal device 100, and therefore, a message requesting acquisition of the UE context (for example, Retrieve \ UE \ Context \ Request). ) Is transmitted to the base station device 200-1 holding the AS context (S22).

Hereinafter, the terminal device 100 may be shifted to the inactive state, and the base station device 200 holding the AS context may be referred to as an anchor base station device, and the base station device 200 to which the terminal device 100 in the inactive state may be referred to as a serving base station device. is there. Note that the anchor base station device may be the base station device to which the terminal device first connects, and the serving base station device may be the base station device to which the terminal device first connects as the terminal moves.

The UE context is wireless channel setting information (Wireless channel setting information or wireless channel configuration), and includes, for example, bearer information, an identifier of the terminal device 100, and information related to wireless used for wireless communication. The UE context also holds the control device 300 in addition to the base station device 200. The above-mentioned line setting information and the above-mentioned wireless line setting information are different. The wireless line setting information relates to wireless communication settings, and the line setting information relates to wireless communication and settings related to data transmission in a network.

Upon receiving the Retrieve \ UE \ Context \ Request, the base station apparatus 200-1 transmits the message (for example, Retrieve \ UE \ Context \ Response) in response to the UE context acquisition request, including the UE context and the AS context of the corresponding terminal apparatus 100. The AS context is transmitted to the station device 200-2 (S23), and the transmitted AS context is released (deleted from the internal memory) (S24).

When receiving the Retrieve \ UE \ Context \ Response, the base station apparatus 200-2 resumes the RRC connection with the terminal apparatus 100 using the acquired AS context and UE context, and a message notifying the resumption of the RRC connection (for example, RRCConnectionResume). ) Is transmitted to the terminal device 100 (S25).

The terminal device 100 receives the RRCConnectionResume (S25), and transitions to the CONNECTED state (S26).

FIG. 4 is a diagram showing an example of a sequence when an incoming call is received by the terminal device 100 in the inactive state. The terminal device 100 moves from the terminal device 100-a to the position of the terminal device 100-b, and is located within the communication area of the base station device 200-2.

(4) The terminal device 100 is in the INACTIVE state (S20). When an incoming call to the terminal device 100 occurs, the control device 300 notifies the base station device 200-1, which is the anchor base station device, that the incoming call has occurred to the terminal device 100 (calling) message (for example, paging). Is transmitted (S30).

The base station apparatus 100-1 notifies the adjacent base station apparatus 200 (including the base station apparatus 200-2) that the terminal apparatus 100 has received an incoming call in order to make an incoming call to the terminal apparatus 100 ( For example, RAN (Radio \ Access \ Network) Paging is transmitted (S31).

Upon receiving the RAN Paging, the base station apparatus 200-2 notifies (reports) a message (for example, Paging) indicating that an incoming call has occurred to the terminal apparatus 100 to the located terminal apparatus (S32).

(4) When the terminal device 100 receives the Paging including itself (S32), the terminal device 100 transmits an RRCConnectionResumeRequest to the base station device 200-2 to start communication (S21). Thereafter, steps S22 to S26 are the same as steps S22 to S26 shown in FIG.

<Transition to IDLE state>
In some cases, the anchor base station apparatus cancels the inactive state of the terminal apparatus 100 and shifts to the IDLE state by an instruction from the control apparatus 300 or voluntarily. At this time, the anchor base station device releases the AS context.

がある There is a first method in which the AS context held by the terminal device 100 is not released when the transition to the IDLE state is triggered by the base station device (no instruction or request regarding the AS context is issued to the adjacent base station device or the terminal device). However, in the first method, the terminal device 100 keeps holding the AS context, executes the restart of the RRC connection from the inactive state, and fails to restart the RRC connection. When the terminal device 100 fails to resume the RRC connection, the terminal device 100 can get an opportunity to release the AS context, but a sequence in which the resume of the RRC connection fails is executed.

When the base station apparatus transitions to the IDLE state, for example, the terminal apparatus 100 is called by RAN @ Paging, the incoming call sequence is executed with the responding terminal apparatus 100, and the terminal apparatus 100 is caused to execute RRC connection resumption. There is a method. In the second method, as in the first method, the failure of the restart of the RRC connection causes the AS context held by the terminal device 100 to be released. However, in the second scheme, an incoming sequence is executed between the terminal device 100 and the base station device 200-1, and between the base station device 200-1 and the base station device 200-2.

As described above, in the first method and the second method, an extra sequence occurs in both, and communication resources and the processing capacity of each device cannot be used efficiently.

Therefore, in the present embodiment, when transitioning to the IDLE state, base station apparatus 200-1 and terminal apparatus 100 execute a scheme different from the first scheme and the second scheme.

[First Embodiment]
First, a first embodiment will be described.

<Transition from the INACTIVE state to the IDLE state in the first embodiment>
The control device 300, the base station device 200, and the terminal device 100 each have a processor and a memory. Each process of each device is realized by loading a program stored in each device into a memory, and executing the loaded program by a processor.

FIG. 5 is a diagram showing an example of a sequence of transition from the inactive state to the IDLE state in the first embodiment. The sequence shown in FIG. 5 is a sequence in a communication system having two types of contexts, a first type context and a second type context. The first type context is, for example, a UE context, and the second type context is, for example, an AS context.

(4) The terminal device 100 is in the INACTIVE state (S40). Further, the terminal device 100 holds, for example, a second type context (S41).

(4) The control device 300 transmits to the base station device 200-1 (anchor base station device) a type 1 context deletion instruction instructing release of the type 1 context (S42).

Upon receiving the first type context deletion instruction (S42), the base station device 200-1 indicates that the second type context corresponding to the terminal device 100 corresponding to the first type context to be released is a release target. A two-context deletion notification is transmitted to the adjacent base station 200-2 (S43). Note that the base station device 200-1 transmits the second type context deletion notification to all adjacent base station devices 200.

Then, the base station device 200-1 releases the first type context and the second type context (S44), and transmits to the control device 300 a first type context deletion completion indicating that the release of the first type context is completed. Yes (S45).

Upon receiving the second type context deletion notification (S43), the base station device 200-2 determines that the second type context of the terminal device 100 (target terminal device) included in the second type context deletion notification is to be released. Recognition (S46) and transition to the IDLE state (S47).

When the base station device 200-2 recognizes that the second type context of the target terminal device is to be released, it instructs the terminal device 100 to release the second type context, for example. Further, upon recognizing that the second type context of the target terminal device is to be released, the base station device 200-2, for example, resumes the RRC connection from the target terminal device (transition from the INACTIVE state to the CONNECTED state). ) Is rejected (rejected).

In the first embodiment, when receiving the release instruction of the first type context (for example, the UE context), the anchor base station device also releases the second type context (for example, the AS context). Then, the anchor base station apparatus notifies the serving base station apparatus included in the adjacent base station apparatus that the second type context of the target terminal apparatus is to be released. By this means, the serving base station apparatus can recognize that the type 2 context of the target terminal apparatus is to be released, that is, that the target terminal apparatus is handled in the IDLE state instead of the INACTIVE state. If the serving base station apparatus can recognize that the type 2 context of the target terminal apparatus is to be released, the serving base station apparatus rejects the subsequent restart of the RRC connection from the target terminal apparatus, and instructs the target terminal apparatus to release the type 2 context to the target terminal apparatus. Can be performed without inquiring of the anchor base station, the execution of unnecessary sequences is suppressed, and a smooth state transition can be performed.

[Second embodiment]
Next, a second embodiment will be described.

<Configuration example of base station device>
FIG. 6 is a diagram illustrating a configuration example of the base station apparatus 200. The base station device 200 includes a CPU (Central Processing Unit) 210, a storage 220, a memory 230, a NIC (Network Interface Card) 240, and an RF (Radio Frequency) circuit 250.

The storage unit 220 is an auxiliary storage device that stores programs and data, such as a flash memory, a hard disk drive (HDD), or a solid state drive (SSD). The storage 220 stores a communication control program 221, an anchor base station program 222, and a serving base station program 223.

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 programs store data.

The NIC 240 is a device that performs communication by connecting to the control device 300 and other communication devices. The NIC 240 may be connected to another device via a hub or a switch.

The RF circuit 250 is an interface that performs wireless communication with the terminal device 100 and performs communication. The RF circuit 250 has, for example, an antenna and wirelessly connects to the terminal device 100 in the communication area.

The CPU 210 is a processor that loads a program stored in the storage 220 into the memory 230, executes the loaded program, and realizes each process.

(4) The CPU 210 performs a communication control process by executing the communication control program 221. The communication control process is a process of wirelessly connecting to the terminal device 100 and controlling communication of the terminal device 100 wirelessly connected.

The CPU 210 executes the anchor base station program 222 to construct a receiving unit, a first management unit, and a second management unit, and execute an anchor base station process. The anchor base station process manages the AS context and restarts the RRC connection of the terminal device 100 when the own device is the anchor base station device.

{Circle around (2)} By executing the UEContextReleaseCommand receiving module 2221 of the anchor base station program 222, the CPU 210 constructs the receiving unit, the first managing unit, and the second managing unit, and performs the UEContextReleaseCommand receiving process. The UEContextReleaseCommand reception process is a process when the UEContextReleaseCommand transmitted from the control device 300 is received, and is a process for releasing the AS context and the UE context. Further, the UEContextReleaseCommand reception process is a process of notifying the adjacent base station device that the AS context is to be released. In addition, the base station apparatus 200 notifies the AS message that the AS context is to be released, for example, in a specific message, the identifier of the terminal apparatus (release target terminal apparatus) corresponding to the AS context and the I-RNTI of the terminal apparatus. And transmits to the adjacent base station apparatus.

By executing the serving base station program 223, the CPU 210 constructs a release target terminal storage unit and a communication control unit, and executes serving base station processing. The serving base station process stores the identifier and I-RNTI of the terminal device whose AS context is to be released and rejects the resumption of the RRC connection from the release target terminal device when the own device is the serving base station device. It is a process that does.

Also, the CPU 210 executes the Delete \ UE \ Context \ Request receiving module 2231 included in the serving base station program 223, thereby constructing the release target terminal storage unit and the communication control unit, and performs the Delete \ UE \ Context \ Request receiving process. The Delete \ UE \ Context \ Request request process is a process of receiving the Delete \ UE \ Context \ Request transmitted from the anchor base station device, and is a process of storing the I-RNTI and the identifier of the terminal device included in the Delete \ UE \ Context \ Request.

<Example of terminal device configuration>
FIG. 7 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, and an RF circuit 150.

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

The memory 130 is an area for loading a program stored in the storage 120. The memory 130 is also used as an area for storing data by the program.

The RF circuit 150 is an interface that performs wireless communication with the base station device 200 and performs communication. The RF circuit 150 has, for example, an antenna and wirelessly connects to the base station device 200 in the communication area where the own device is located.

The CPU 110 is a processor that loads a program stored in the storage 120 into the memory 130, executes the loaded program, and realizes each process.

(4) The CPU 110 performs a communication process by executing the communication program 121. The communication process is a process of wirelessly connecting to the base station device 200 and communicating with the base station device 200. The communication process is a process of wirelessly connecting to the base station device 200 and performing communication with another communication device via the base station device 200.

(4) The CPU 110 executes the AS context management program 122 to construct a broadcast information receiving unit and a context management unit, and performs an AS context management process. The AS contest management process is a process of receiving notification information that triggers the release of the AS context and releasing the AS context.

(4) The CPU 110 executes the paging reception module of the AS context management program 122 to construct a broadcast information receiving unit and a context management unit, and performs paging reception processing. The paging reception process is a process for receiving a paging to be notified, which is a normal incoming call process or a process of releasing an AS context.

<Transition from the INACTIVE state to the IDLE state in the second embodiment>
FIG. 8 is a diagram illustrating an example of a sequence of transition from the inactive state to the IDLE state according to the second embodiment. The terminal device 100 is in the INACTIVE state (S100). When a trigger to release the UE context occurs, the base station device 200-1 (anchor base station device) transmits a message (for example, UEContextReleaseRequest) requesting release of the UE context to the control device 300 (S101). Note that, when the release trigger of the UE context occurs on the control device 300 side, the process S101 may be omitted.

If the control device 300 permits the release of the UE context, the control device 300 transmits a message (for example, UEContextReleaseCommand) instructing the release of the UE context to the base station device 200-1 (S102).

Upon receiving the UEContextReleaseCommand (S102), the base station apparatus 200-1 performs a UEContextReleaseCommand receiving process (S103).

FIG. 9 is a diagram illustrating an example of a process flowchart of the UEContextReleaseCommand reception process S103. The base station device 200 confirms whether or not the AS context corresponding to the terminal device 100 to be released of the UE context included in the UEContextReleaseCommand is held (S103-1).

When the base station apparatus 200 holds the AS context of the terminal apparatus 100 (Yes in S103-1), the base station apparatus 200 releases the AS context and the UE context of the terminal apparatus 100 (S103-2).

Then, the base station apparatus 200 transmits RAN Paging including a list of target terminal apparatuses (for example, ASContextDeleteList) for releasing the AS context to the adjacent base station (S103-3).

On the other hand, when the base station apparatus 200 does not hold the AS context of the terminal apparatus 100 (No in S103-1), the base station apparatus 200 releases the UE context when holding the UE context of the terminal apparatus 100 (S103). -4).

When the base station apparatus 200 completes the processing S103-3 or S103-4, the base station apparatus 200 transmits a message (for example, UEContextReleaseComplete) notifying that the release of the UE context has been completed to the control apparatus 300 (S103-5).

Returning to the sequence in FIG. 8, the base station apparatus 200-1 holds the AS context of the terminal apparatus 100 in the UEContextReleaseCommand reception processing S103 (Yes in S103-1 in FIG. 9), and thus releases the AS context and the UE context. (S103-2 in FIG. 9). Then, the base station apparatus 200-1 transmits RAN @ Paging including releasing the terminal apparatus 100 (Delete) to the base station apparatus 200-2 (serving base station apparatus) included in the adjacent base station apparatus (S104). , S103-3 in FIG. 9). Further, base station apparatus 200-2 transmits UEContextReleaseComplete to control apparatus 300 (S105, S103-5 in FIG. 9).

Upon receiving the RAN @ Paging (S104), the base station apparatus 200-2 reports Paging (call control information) including information included in the RAN @ Paging (control information) to the terminal device 100 in the own cell (S106). .

(4) Upon receiving the paging (S106), the terminal device 100 performs paging reception processing (S107).

FIG. 10 is a diagram illustrating an example of a processing flowchart of paging reception processing S107. The terminal device 100 checks whether or not the received Paging includes ASContextDeleteList (S107-1).

(4) If the ASContextDeleteList is not included (No in S107-1), the terminal device 100 performs an incoming call process (S107-4), and ends the process.

On the other hand, when the ASContextDeleteList is included (Yes in S107-1), the terminal device 100 checks whether the identifier (UEContextID) of the target terminal device included in the ASContextDeleteList matches the I-RNTI of the own device ( S107-2). That is, the terminal device 100 checks whether the AS context held by the terminal device 100 is a release target.

If the terminal device 100 matches the I-RNTI of the terminal device itself (Yes in S107-2), the terminal device 100 releases the held AS context (S107-3), and ends the process.

On the other hand, if the terminal device 100 does not match the I-RNTI of its own device (No in S107-2), the process ends.

Returning to the sequence of FIG. 8, the terminal device 100 determines that the release target terminal included in the received Paging is its own device (Yes in S107-2 of FIG. 10), and releases the AS context (S107 of FIG. 10). -3), transition to the IDLE state (S108).

FIG. 11 is a diagram illustrating an example of a message format of RAN Paging. RAN @ Paging indicates that when Delete is set in Paging @ type, the RAN @ Paging is a message for notifying the release of the AS context. Also, in RAN \ Paging, when Delete is set in Paging \ type, I-RNTI corresponding to the AS context to be released is set in UE \ RAN \ Paging \ Identify.

FIG. 12 is a diagram showing an example of a Paging message format. Paging indicates that when the Context Type ASContextDeleteList is set, the Paging is a message for notifying the release of the AS context. Paging includes an I-RNTI corresponding to an AS context to be released or an identifier of a terminal device in an ASContextDeleteList of a CHOICE type.

In the second embodiment, the anchor base station device causes the terminal device 100 to release the AS context held by the terminal device 100 using Paging. As a result, the terminal device 100 does not request the restart of the RRC connection, the sequence in which the restart of the RRC connection fails is not executed, and the execution of the extra sequence is suppressed.

[Third Embodiment]
Next, a third embodiment will be described. Configuration examples of the base station apparatus 200 and the terminal apparatus 100 are the same as the configuration examples shown in FIGS. 6 and 7, respectively.

<Transition from the INACTIVE state to the IDLE state in the third embodiment>
FIG. 13 is a diagram illustrating an example of a sequence of transition from the inactive state to the idle state according to the third embodiment. The terminal device 100 is in the INACTIVE state (S200). When the opportunity to release the UE context occurs, the base station device 200-1 (anchor base station device) transmits a UEContextReleaseRequest to the control device 300 (S201). In addition, when the release trigger of the UE context occurs on the control device 300 side, the process S201 may be omitted.

(4) When permitting release of the UE context, the control device 300 transmits a UEContextReleaseCommand to the base station device 200-1 (S202).

Upon receiving the UEContextReleaseCommand (S202), the base station apparatus 200-1 performs a UEContextReleaseCommand receiving process (S203).

FIG. 14 is a diagram illustrating an example of a process flowchart of the UEContextReleaseCommand reception process S203. The base station device 200 confirms whether or not the AS context corresponding to the terminal device 100 to be released of the UE context included in the UEContextReleaseCommand is held (S203-1).

When the base station apparatus 200 holds the AS context of the terminal apparatus 100 (Yes in S203-1), the base station apparatus 200 releases the AS context and the UE context of the terminal apparatus 100 (S203-2). Then, the base station device 200 transmits UEContextReleaseComplete to the control device 300 (S203-3).

{Furthermore, the base station apparatus 200 transmits a message (for example, Delete \ UE \ Context \ Request) including the I-RNTI corresponding to the AS context to be released to the adjacent base station (S203-4). The fact that the I-RNTI is to be released indicates, for example, that the terminal device 100 corresponding to the I-RNTI has transitioned from the INACTIVE state to another state.

{Further, the base station apparatus 200 waits to receive a message (for example, Delete \ UE \ Context \ Response) indicating that it has responded to Delete \ UE \ Context \ Request from all the adjacent base station apparatuses (No in S203-5).

When the base station apparatus 200 receives Delete \ UE \ Context \ Response from all adjacent base station apparatuses (Yes in S203-5), the processing ends.

On the other hand, when the base station apparatus 200 does not hold the AS context of the terminal apparatus 100 (No in S203-1), and releases the UE context of the terminal apparatus 100, it releases the UE context (S203). -6), UEContextReleaseComplete is transmitted to control device 300 (S203-7), and the process ends.

Returning to the sequence in FIG. 13, the base station apparatus 200-1 holds the AS context of the terminal apparatus 100 in the UEContextReleaseCommand reception processing S203 (Yes in S203-1 in FIG. 14), and thus releases the AS context and the UE context. Then (S203-2 in FIG. 14), UEContextReleaseComplete is transmitted to the control device 300 (S204, S203-3 in FIG. 14). Further, the base station apparatus 200-1 transmits a Delete \ UE \ Context \ Request including the terminal apparatus 100 to the base station apparatus 200-2 (serving base station apparatus) included in the adjacent base station apparatus (S205, S203 in FIG. 14). -4).

Upon receiving the Delete UE Context Request (S205), the base station apparatus 200-2 performs the Delete UE Context Request reception process (S206).

FIG. 15 is a diagram showing an example of a processing flowchart of Delete \ UE \ Context \ Request reception processing S206. The base station device 200 stores that the I-RNTI of the terminal device 100 included in the received Delete \ UE \ Context \ Request has been released (S206-1). Then, base station apparatus 200 transmits Delete \ UE \ Context \ Response to the source base station apparatus (S206-2), and ends the process.

Returning to the sequence in FIG. 13, the base station device 200-2 stores that the I-RNTI of the terminal device 100 has been released in the Delete \ UE \ Context \ Request reception process S206 (S206-1 in FIG. 15), and the Delete UE \ Context \ Response is transmitted to base station apparatus 200-1 (S207, S206-2 in FIG. 15). Then, the terminal device 100 transitions to the IDLE state (S208).

For example, when an opportunity to start communication occurs, the terminal device 100 transmits an RRCConnectionResumeRequest to the base station device 200-2 to restart the RRC connection because the AS context is held (S209).

When the base station apparatus 200-2 receives the RRCConnectionRequestRequest (S209), it performs an RRCConnectionRequestRequest reception process (S210).

FIG. 16 is a diagram illustrating an example of a processing flowchart of RRCConnectionResumeRequest reception processing S210. The base station device 200 confirms whether or not the I-RNTI included in the received RRCConnectionResumeRequest has been released (S210-1).

If the I-RNTI has not been released (No in S210-1), the base station apparatus 200 permits the terminal apparatus 100 to restart the RRC connection, and performs the RRC connection restart processing (S210-2). The RRC connection resumption process transmits an RRCConnectionResume to the terminal device 100 when the own device holds the AS context, and acquires the AS context from the anchor base station device when the own device does not hold the AS context. Is a process of transmitting an RRCConnectionResume to the.

On the other hand, if the I-RNTI has been released (Yes in S210-1), the base station device 200 transmits an RRCConnectionReject to the terminal device 100 (S210-3).

Returning to the sequence of FIG. 13, in the RRCConnectionResumeRequest reception process S210, since the I-RNTI corresponding to the terminal device 100 has been released (Yes in S210-1 in FIG. 16), the base station device 200-2 transmits the RRCConnectionReject to the terminal. The data is transmitted to the device 100 (S211; S210-3 in FIG. 16).

FIG. 17 is a diagram showing an example of a message format of Delete \ UE \ Context \ Request. The Delete UE Context Request includes “Message”, “Procedure Code”, “Type of Message”, and “UE Context ID”.

“Message” sets the message type. In “Procedure @ Code”, a procedure code is set. For example, a procedure code (eg, 23) not used in other messages is set. In "Type @ of @ Message", a message type is set. For example, it is set that the message is an initial message (Initiating @ Message). In “UE \ Context \ ID”, the identifier of the AS context to be released is set, and for example, I-RNTI is set.

FIG. 18 is a diagram showing an example of a message format of Delete \ UE \ Context \ Response. Delete \ UE \ Context \ Response includes "Message", "Procedure Code", and "Type of Message".

“Message” sets the message type. In “Procedure @ Code”, a procedure code is set. For example, a procedure code (eg, 23) not used in other messages is set. In "Type @ of @ Message", a message type is set. For example, it is set that the message is a response message (Successful @ Outcome) indicating that the request in the initial message is successful.

In the third embodiment, the anchor base station device uses Delete \ UE \ Context \ Request to determine that the I-RNTI of the terminal device 100 is to be released, that is, the AS context of the terminal device 100 is to be released. This is notified to the serving base station device. Then, the serving base station device stores that the I-RNTI of the terminal device 100 is to be released. By this means, the serving base station device can reject the request for resuming the RRC connection from the terminal device 100 without inquiring of the anchor base station device, and can suppress the execution of unnecessary sequences.

[Other embodiments]
The processing in each embodiment may be combined.

The base station apparatus 200 may have, for example, both of the processing of transitioning from the inactive state to the IDLE state in the second and third embodiments. In this case, the base station apparatus 200 may determine which process to perform, for example, according to a predetermined condition.

10: Communication system 100: Terminal device 110: CPU
120: storage 121: communication program 122: AS context management program 130: memory 150: RF circuit 200: base station device 210: CPU
220: storage 221: communication control program 222: anchor base station program 223: serving base station program 230: memory 250: RF circuit 300: control device

Claims

A terminal device, a base station device capable of performing communication with the terminal device, and a base station device in a communication system including a control device,
A receiving unit that receives control information related to release of the first type context from the control device;
A first management unit that releases the first type context;
And a second management unit that releases the second type context and notifies other base station devices of control information related to the release of the second type context when the base station device has the second type context.
When the terminal device resumes communication with the another base station device, the second type context can transition to a first state in which communication can be performed by executing a part of a connection procedure. The base station apparatus according to claim 1, wherein the terminal apparatus is line setting information between the base station apparatus that was communicating when the terminal apparatus transitioned to the second state and the terminal apparatus.
The second management unit includes control information related to release of the second type context in paging control information, and notifies the other base station device of control information requesting release of the second type context. The base station device according to claim 2.
The terminal device, upon receiving the call control information, releases the second type context owned by the own device if the own device is a terminal device requested to release the second type context. The base station device as described in the above.
The base station device according to claim 3, wherein the paging control information is Paging, and the notification to the other base station device is performed by RAN Paging.
Further, when receiving control information regarding the release of the second type context, a release target terminal storage unit that stores information on a release target terminal device that releases the second type context;
The base station device according to claim 2, further comprising: a communication control unit configured to reject a request from the terminal device when the terminal device is the release target terminal device when the terminal device is requested to resume communication.
The communication control unit, when requested to resume communication from the terminal device, if the terminal device is not the terminal device to be released, permits the request from the terminal device, executes a part of the connection procedure The base station device according to claim 6, wherein the terminal device is caused to transition to the first state.
The base station device according to claim 2, wherein the first state is a CONNECTED state, and the second state is an INACTIVE state.
A terminal device, a base station device that communicates with the terminal device, and a control device for the base station device, a terminal device in a communication system,
When the first base station apparatus receiving the control information related to the release of the first type context from the control apparatus has the second type context, the control information related to the release of the second type context is transmitted from the first base station apparatus. A broadcast information receiving unit that receives broadcast information including the control information from the notified second base station device;
A context management unit that releases the second type context of the terminal device.
A terminal device, a base station device that communicates with the terminal device, and a communication system including a control device,
The control device transmits a release instruction instructing the base station device to release the first type context,
The base station device releases the first type context, and when the base station device has the second type context, releases the second type context, and transmits control information regarding the release of the second type context to another base station device and the terminal device. Notify,
The communication system, wherein the terminal device receives control information on release of the second type context and releases the second type context.