KR20180033392A - UE context processing methods and appartus for Light Connected UE - Google Patents

Abstract

The present invention relates to a user equipment context processing method and an apparatus for user equipment (UE) formed in a light connection condition. More specifically, the present invention provides a method and an apparatus, wherein a method for processing a UE context comprises the following steps: light connection UE performs cell-reselection in a base station cell instead of an anchor base station; and the UE context is effectively used by a new base station.

Description

[0001] The present invention relates to a UE context processing method and apparatus for a light connection terminal,

 The present invention relates to a terminal context handling method and apparatus of a terminal configured in a light connection state.

The present invention provides a method and apparatus for processing a terminal context, the method comprising: a light connection terminal cell selection to a base station cell other than an anchor base station; and a step in which the new base station effectively utilizes the terminal context.

FIG. 1 is a diagram for explaining a conventional LTE message processing procedure.
2 is a diagram for explaining a UE initiated connection resume procedure according to the related art.
FIG. 3 is a diagram for explaining an example of a RAN-based paging and a terminal context using method according to the present invention.
FIG. 4 is a view for explaining another example of RAN-based paging and terminal context using method according to the present invention.
5 is a view for explaining another example of RAN-based paging and terminal context utilization method according to the present invention.
6 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.
7 is a diagram illustrating a configuration of a user terminal according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Herein, the MTC terminal may mean a terminal supporting low cost (or low complexity) or a terminal supporting coverage enhancement. In this specification, the MTC terminal may mean a terminal supporting low cost (or low complexity) and coverage enhancement. Alternatively, the MTC terminal may refer to a terminal defined in a specific category for supporting low cost (or low complexity) and / or coverage enhancement.

In other words, the MTC terminal in this specification may mean a newly defined 3GPP Release-13 low cost (or low complexity) UE category / type for performing LTE-based MTC-related operations. Alternatively, the MTC terminal may support enhanced coverage over the existing LTE coverage or a UE category / type defined in the existing 3GPP Release-12 or lower that supports low power consumption, or a newly defined Release-13 low cost low complexity UE category / type.

The wireless communication system in the present invention is widely deployed to provide various communication services such as voice, packet data and the like. A wireless communication system includes a user equipment (UE) and a base station (BS, or eNB). The user terminal in this specification is a comprehensive concept of a terminal in wireless communication. It is a comprehensive concept which means a mobile station (MS), a user terminal (UT), an SS (User Equipment) (Subscriber Station), a wireless device, and the like.

A base station or a cell generally refers to a station that communicates with a user terminal and includes a Node-B, an evolved Node-B (eNB), a sector, a Site, a BTS A base transceiver system, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and a small cell.

That is, the base station or the cell in this specification is interpreted as a comprehensive meaning indicating a partial region or function covered by BSC (Base Station Controller) in CDMA, NodeB in WCDMA, eNB in LTE or sector (site) And covers various coverage areas such as megacell, macrocell, microcell, picocell, femtocell and relay node, RRH, RU, and small cell communication range.

Since the various cells listed above exist in the base station controlling each cell, the base station can be interpreted into two meanings. i) the device itself providing a megacell, macrocell, microcell, picocell, femtocell, small cell in relation to the wireless region, or ii) indicating the wireless region itself. i indicate to the base station all devices that are controlled by the same entity or that interact to configure the wireless region as a collaboration. An eNB, an RRH, an antenna, an RU, an LPN, a point, a transmission / reception point, a transmission point, a reception point, and the like are exemplary embodiments of a base station according to a configuration method of a radio area. ii) may indicate to the base station the wireless region itself that is to receive or transmit signals from the perspective of the user terminal or from a neighboring base station.

Therefore, a base station is collectively referred to as a base station, collectively referred to as a megacell, macrocell, microcell, picocell, femtocell, small cell, RRH, antenna, RU, low power node do.

Herein, the user terminal and the base station are used in a broad sense as the two transmitting and receiving subjects used to implement the technical or technical idea described in this specification, and are not limited by a specific term or word. The user terminal and the base station are used in a broad sense as two (uplink or downlink) transmitting and receiving subjects used to implement the technology or technical idea described in the present invention, and are not limited by a specific term or word. Here, an uplink (UL, or uplink) means a method of transmitting / receiving data to / from a base station by a user terminal, and a downlink (DL or downlink) .

There are no restrictions on multiple access schemes applied to wireless communication systems. Various multiple access schemes such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), OFDM-FDMA, OFDM- Can be used. An embodiment of the present invention can be applied to asynchronous wireless communication that evolves into LTE and LTE-advanced via GSM, WCDMA, and HSPA, and synchronous wireless communication that evolves into CDMA, CDMA-2000, and UMB. The present invention should not be construed as limited to or limited to a specific wireless communication field and should be construed as including all technical fields to which the idea of the present invention can be applied.

A TDD (Time Division Duplex) scheme in which uplink and downlink transmissions are transmitted using different time periods, or an FDD (Frequency Division Duplex) scheme in which they are transmitted using different frequencies can be used.

In systems such as LTE and LTE-advanced, a standard is constructed by configuring uplink and downlink based on a single carrier or carrier pair. The uplink and the downlink are divided into a Physical Downlink Control Channel (PDCCH), a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid ARQ Indicator CHannel, a Physical Uplink Control CHannel (PUCCH), an Enhanced Physical Downlink Control Channel (EPDCCH) Transmits control information through the same control channel, and is configured with data channels such as PDSCH (Physical Downlink Shared CHannel) and PUSCH (Physical Uplink Shared CHannel), and transmits data.

On the other hand, control information can also be transmitted using EPDCCH (enhanced PDCCH or extended PDCCH).

In this specification, a cell refers to a component carrier having a coverage of a signal transmitted from a transmission point or a transmission point or transmission / reception point of a signal transmitted from a transmission / reception point, and a transmission / reception point itself .

The wireless communication system to which the embodiments are applied may be a coordinated multi-point transmission / reception system (CoMP system) or a coordinated multi-point transmission / reception system in which two or more transmission / reception points cooperatively transmit signals. antenna transmission system, or a cooperative multi-cell communication system. A CoMP system may include at least two multipoint transmit and receive points and terminals.

The multi-point transmission / reception point includes a base station or a macro cell (hereinafter referred to as 'eNB'), and at least one mobile station having a high transmission power or a low transmission power in a macro cell area, Lt; / RTI >

Hereinafter, a downlink refers to a communication or communication path from a multipoint transmission / reception point to a terminal, and an uplink refers to a communication or communication path from a terminal to a multiple transmission / reception point. In the downlink, a transmitter may be a part of a multipoint transmission / reception point, and a receiver may be a part of a terminal. In the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of multiple transmission / reception points.

Hereinafter, a situation in which a signal is transmitted / received through a channel such as PUCCH, PUSCH, PDCCH, EPDCCH, and PDSCH is expressed as 'PUCCH, PUSCH, PDCCH, EPDCCH and PDSCH are transmitted and received'.

In the following description, an indication that a PDCCH is transmitted or received or a signal is transmitted or received via a PDCCH may be used to mean transmitting or receiving an EPDCCH or transmitting or receiving a signal through an EPDCCH.

That is, the physical downlink control channel described below may mean a PDCCH, an EPDCCH, or a PDCCH and an EPDCCH.

Also, for convenience of description, EPDCCH, which is an embodiment of the present invention, may be applied to the portion described with PDCCH, and EPDCCH may be applied to the portion described with EPDCCH according to an embodiment of the present invention.

Meanwhile, the High Layer Signaling described below includes RRC signaling for transmitting RRC information including RRC parameters.

The eNB performs downlink transmission to the UEs. The eNB includes a physical downlink shared channel (PDSCH) as a main physical channel for unicast transmission, downlink control information such as scheduling required for reception of PDSCH, and uplink data channel A physical downlink control channel (PDCCH) for transmitting scheduling grant information for transmission in a Physical Uplink Shared Channel (PUSCH). Hereinafter, the transmission / reception of a signal through each channel will be described in a form in which the corresponding channel is transmitted / received.

In LTE  State transition Signaling

In the conventional LTE technology, the terminal and the network state consist of two states: an idle state and a connected state. The state is consistent between the terminal and the network. The state (RRC state and ECM state) in the radio network (E-UTRAN) and the core network are matched. That is, when the UE transits to the RRC-IDLE state, the UE enters the ECM-IDLE state. When the UE transitions to the RRC-CONNECTED state, the UE enters the ECM-CONNECTED state. In order for an idle terminal to transmit data, a complicated signaling process as shown in FIG. 1 has to be performed. In particular, when a terminal transmits a small amount of data, it becomes a large overhead.

If the terminal periodically transmits a small amount of data, the overhead will be continuously generated. In order to reduce the overhead due to the state transition, the terminal may be kept in a connected state. However, in this case, even if there is no data transmission, the battery is consumed for measurement and reporting and the signaling overhead is increased .

NB- IoT  Suspend / Resume for terminal Procedure

In 3GPP Rel-13, standardization for supporting narrow band IoT terminals was performed. The narrow band IoT terminal can be operated in a stationary state. That is, in a fixed position or within a certain range. Rel-13 NB-IoT standardization supports Suspend / Resume procedure in terminal and base station. In the RRC connection release, the base station can request the terminal to maintain the AS context in the RRC_IDLE state. When the UE receives the RRC connection release message including the RRC suspend information and transitions to the RRC IDLE state (or before the BS sends the message to the UE), the BS transmits an S1 message to the core network The ECM enters the IDLE state.

The RRC connection resume procedure is used for RRC connected state transitions in the RRC IDLE used for resuming the RRC connection previously stored in the UE and the base station. When the MS initiates the RRC connection resume procedure and transitions to the RRC Connected state (after the BS sends an RRC connection resume message to the MS), the BS transmits the RRC connection resume message to the core network through the interface between the BS and the core network S1) message to enter the ECM CONNECTED state. 2 shows a UE initiated connection resume procedure according to the prior art.

Light Connected

3GPP is conducting a study on lightweight connections to reduce signaling. The main functions for a lightly connected UE are as follows.

- The S1 connection is maintained in an anchor eNB and is in an active state.

- RAN initiation paging is supported.

- The paging procedure is controlled by the anchor base station.

- The RAN-based paging area may be configured to be terminal specific.

- When performing the selly selection based mobility, the same mechanism as the selly selection mechanism of RRC IDLE is used.

- The terminal AS context is maintained in the terminal and the anchor base station.

- In the MME, the ECM state is the ECM-CONNECTED state.

As described above, in the conventional mobile communication technology, there has been a signaling overhead problem due to state transition, and a study has been conducted on an RRC state (hereinafter referred to as a light connection state for convenience of description) for reducing the signaling overhead. It is possible to perform the selec- tion according to the movement of the terminal composed of the light connection. RAN-based paging may be provided for a terminal if the terminal is seleled to a base station cell other than an anchor base station in a state where the terminal does not depart from the paging area configured by the anchor base station. However, no specific method and procedure was provided. In particular, when the light connection terminal performs cell selection on the base station cell other than the anchor base station, the new base station does not have the terminal context, and thus the new base station has difficulty in effectively utilizing the terminal context stored in the anchor base station.

The cell reselection can be performed according to the movement of the terminal composed of the conventional light connection. RAN-based paging may be provided for a terminal if the terminal is seleled to a base station cell other than an anchor base station in a state where the terminal does not depart from the paging area configured by the anchor base station. However, no specific method and procedure was provided. In particular, when the light connection terminal performs cell selection on the base station cell other than the anchor base station, the new base station does not have the terminal context, and thus the new base station has difficulty in effectively utilizing the terminal context stored in the anchor base station.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for effectively performing RAN-based paging for a terminal having a light connection. And an object of the present invention is to provide a method and an apparatus which enable a new base station to effectively use a terminal context when a light connection terminal performs cell selection on a base station cell other than an anchor base station.

The present invention can be applied not only to a Rel-13 NB-IoT terminal but also to a general mobile communication terminal. The present invention can be applied not only to an LTE mobile communication terminal but also to a next generation mobile communication (5G mobile communication / New RAT) terminal.

For convenience of explanation, the base station may represent an eNodeB of an LTE / E-UTRAN or a base station (CU, DU, or CU and DU) in a 5G wireless network in which a CU (Central Unit) An entity implemented as a single logical entity).

The selly selection can be triggered as the terminal configured in the lightly connected state moves.

If a lightly connected state terminal moves out of a cell associated with an anchor base station that has made a light connection state, the anchor base station can not know the position of the lightly connected state terminal. In order for the network to track the location of the lightly connected state terminal, the anchor base station may configure the lightly connected state of the terminal by setting the paging area to the terminal Hereinafter, the paging area constituted by the anchor base station is indicated as the paging area, which is for convenience of explanation, but other terms of similar concept are included in the present invention). As an example, the paging area configuration may include information (cell list) of one or more cells for the paging area ID. For example, the cell information may be cell identification information or global cell identification information. The paging area configuration information may include anchor base station identification information and terminal identification information in an anchor base station.

For example, the above-described paging area configuration information may be indicated through a UE-specific RRC reconfiguration message. As another example, the above-described paging area configuration information may be indicated through a UE-specific RRC release message. As another example, the above-described paging area configuration information may be indicated through system information.

According to cell re-selection criteria, if the terminal finds a better suitable cell, the terminal re-selects (or reselects and camps on) it. If the terminal is out of the configured paging area (for example, if the reselected cell is not included in at least one paging area information configured in the terminal), the lightly connected terminal must inform the network. For example, a paging area update can be performed. In another example, if the UE does not leave the configured paging area, the UE continues the sellection selection measurement and the selly selection evaluation. When the condition for cell selection is satisfied, the terminal performs cell selection.

RAN-based paging and terminals for lightweight connected terminals Contact  How to use

Hereinafter, an RAN-based paging method and a terminal context usage method for a lightly connected state terminal according to the present invention will be described. The methods described below may be used individually or in any combination.

1) After the RRC connection resume request, the terminal context request

3 illustrates an example of RAN-based paging and terminal context utilization according to the present invention.

In the prior art, since core network based paging has been performed, RAN based paging has not been performed. Also, according to the related art, when connection resumption is performed to an RRC suspend terminal, the core network connection resumption is performed. Hereinafter, Fig. 3 will be described.

0. When an anchor base station receives downlink data (user data or NAS PDU) for a light connection terminal from a core network entity (S-GW or MME), the anchor base station buffers downlink packets. The anchor base station initiates RAN based paging in the paging area configured in the light connection terminal.

1. An anchor base station transmits a paging message (downlink data notification) to another base station in the paging area.

2. The new base station receiving the paging request from the anchor base station broadcasts the paging message to the mobile station.

3. The lightly connected terminal that has received the paging message transmits an RRC restart request message (for example, an RRC connection resumption request procedure, for convenience of explanation) in order to transition to the RRC connection state. Other procedures can be used to explain.)

4. The new base station sends a request message to the anchor base station to extract / interrogate / fetch / retrieve / get the terminal AS context. For example, this may be a conventional Retrieve UE context request message. In the prior art, this procedure was used for a new base station to extract the terminal context from the base station where the RRC connection is suspended.

As another example, this may be an X2 message distinguished from a conventional Retrieve UE context request message.

5. The anchor base station responds to the new base station, including the terminal AS context. For example, this may be a conventional Retrieve UE context response message. As described above, the prior art required a terminal context extraction to resume the RRC connection and resume the core network connection. Since the new base station has resumed the connection with both the UE and the core network, the information included in the Retrieve UE context response in the prior art is the UE Security Capabilities, the AS Security Information, the UE Aggregate Maximum Bit Rate, the E- -RABs To Be Setup Item (E-RAB ID, E-RAB Level QoS Parameters), and RRC Context information included in the handover preparation information message. If it is desired to extract the UE context information in response to the paging for the light connection terminal, the buffered data for paging must be forwarded to the new base station by the anchor base station. To this end, the Retrieve UE context response may include at least one of uplink GTP tunnel end point information and downlink forwarding information in the E-RABs To Be Setup Item of the E-RABs To Be Setup List. The uplink GTP tunnel endpoint information is used to identify the X2 bearer associated with the E-RAB, which includes the transport layer address and the GTP tunnel endpoint identifier. The downlink forwarding information may indicate that downlink forwarding is proposed.

As another example, this may be an X2 message distinguished from a conventional Retrieve UE context response message. If it is desired to extract the UE context information in response to the paging for the light connection terminal, the buffered data for paging must be forwarded to the new base station by the anchor base station. To this end, the X2 message may include at least one of uplink GTP tunnel end point information and downlink forwarding information in the E-RABs To Be Setup Item of the E-RABs To Be Setup List. The downlink forwarding information may indicate that downlink forwarding is proposed. The uplink GTP tunnel endpoint information is used to identify the S1 transmission bearer associated with the E-RAB (or to identify the X2 transmission bearer associated with the E-RAB), which includes the transport layer address and the GTP tunnel endpoint identifier . For example, the uplink GTP tunnel endpoint is for the S-GW endpoint of the S1 transmission bearer and the new base station can use it to send the uplink PDUs to the S-GW. As another example, the uplink GTP tunnel endpoint is for an anchor base station endpoint of the X2 transmission bearer, and the new base station can use it to send uplink PDUs to the anchor base station.

6. The new base station sends an acknowledgment message containing the downlink GTP tunnel end point information to the E-RABs (accepting) based on the received information to the anchor base station.

The downlink GTP tunnel endpoint information is used to identify the X2 transmission bearer associated with the E-RAB, which includes the transport layer address and the GTP tunnel endpoint identifier. The anchor base station may send the buffered (or received) downlink PDUs to the new base station.

7. The new base station transmits an RRC connection restart message to the UE. As another example, steps 6 and 7 can be performed simultaneously. As another example, step 7 may be performed first and step 6 may be performed later.

8. The anchor base station forwards the buffered data to the new base station.

9. The terminal transmits an RRC connection resumption complete message to the new base station. As another example, steps 8 and 9 can be performed simultaneously. As another example, step 9 may be performed first and step 8 may be performed later.

10. The new base station sends a path switch request message to the core network control entity (MME).

11-12. The core network control entity (MME) performs core network data entity (SGW) and bearer modification procedure.

13. The core network control entity (MME) sends a path switch request acknowledgment / path switch response message to the new base station.

14. Release the terminal context of the anchor base station.

In the RAN-based paging process, in order to transmit data buffered in an anchor base station through a new base station, a message request message of a new base station, a response thereto, and an X2 message Create a bearer. Since the new base station can not know the terminal context information until the new base station receives the terminal context from the anchor base station, it can not allocate or transmit the downlink tunnel end point information for the E-RABs. Thus, May be required.

2) Including terminal context information on RAN-based terminal paging message

In the RAN-based paging process, in order to transmit the data buffered in the anchor base station through the new base station, the message transmission of three times in order to transmit the terminal context request of the new base station, the response thereto, and the acknowledgment message, Can increase the arena delay. For example, when an anchor base station transmits a paging message (downlink data notification) to another base station in a paging area, the anchor base station transmits the paging message including the terminal context information.

FIG. 4 shows another example of RAN-based paging and terminal context utilization according to the present invention. In FIG. 4, only steps 1 and 4 of FIG. 4 which operate differently from FIG. 3 will be described.

1. An anchor base station transmits a paging message (downlink data notification) to another base station in the paging area. The paging message may include terminal context information. For example, the paging message may include the UE Security Capabilities, the AS Security Information, the UE Aggregate Maximum Bit Rate, the E-RABs to Be Setup Item of the E-RABs To Be Setup List Forwarding, UL GTP Tunnel Endpoint), and RRC Context included in the handover preparation information message. For example, the paging message may include at least one of uplink GTP tunnel end point information and downlink forwarding information in the E-RABs To Be Setup Item of the E-RABs To Be Setup List. Another example, a paging message may include the number of E-RABs. For example, the paging message (downlink data notification) transmitted by the anchor base station to another base station in the paging area may be a handover request message. And may include an information element for paging on the handover request message.

4. The new base station sends an acknowledgment message containing the downlink GTP tunnel end point information to the E-RABs (accepting) based on the received information to the anchor base station.

The downlink GTP tunnel endpoint information is used to identify the X2 transmission bearer associated with the E-RAB, which includes the transport layer address and the GTP tunnel endpoint identifier. The anchor base station may send the buffered (or received) downlink PDUs to the new base station.

3) The terminal conveys information related to the data bearer

In the RAN-based paging process, in order to transmit the data buffered in the anchor base station through the new base station, the message transmission of three times in order to transmit the terminal context request of the new base station, the response thereto, and the acknowledgment message, Can increase the arena delay. As another example for solving this problem, the UE may transmit the E-RABs related information to the new base station.

FIG. 5 shows another example of the RAN-based paging and terminal context utilization method according to the present invention. In FIG. 5, only steps 3, 4, and 5 of FIG. 5 that operate differently from FIG. 3 will be described.

3. The lightly connected terminal that has received the paging message transmits an RRC restart request message (for example, an RRC connection resumption request procedure, for convenience of explanation) in order to transition to the RRC connection state. For example, the UE may include at least one of the E-RAB ID stored in the UE and the number of E-RABs stored in the UE in the corresponding message.

4. The new base station sends a request message to the anchor base station to extract / interrogate / fetch / retrieve / get the terminal AS context. For example, this may be a conventional Retrieve UE context request message. As another example, this may be an X2 message distinguished from a conventional Retrieve UE context request message.

For example, the message transmitted by the new base station to the anchor base station may include one or more of the information for distinguishing the E-RAB ID, the downlink GTP tunnel end point information, and the downlink GTP tunnel end point from the E-RABs .

As another example, a message that a new base station transmits to an anchor base station may include one or more of downlink GTP tunnel end point information corresponding to the number of E-RABs and information for distinguishing downlink GTP tunnel end point .

The downlink GTP tunnel endpoint information is used to identify the X2 transmission bearer associated with the E-RAB, which includes the transport layer address and the GTP tunnel endpoint identifier. The anchor base station can use this to transmit the buffered (or received) downlink PDUs to the new base station.

5. The anchor base station responds to the new base station, including the terminal AS context. For example, this may be a conventional Retrieve UE context response message. As another example, this may be an X2 message distinguished from a conventional Retrieve UE context response message.

For example, a message in which an anchor base station replies to a new base station includes a UE Security Capabilities, an AS Security Information, a UE Aggregate Maximum Bit Rate, an E-RABs To Be Setup Item (E-RAB ID, E -LAB Level QoS Parameters, DL Forwarding, UL GTP Tunnel Endpoint), and RRC Context included in the handover preparation information message. In another example, a message that the anchor base station responds to the new base station includes the E-RAB ID, the downlink GTP tunnel end point information, the uplink GTP tunnel end point information, and the uplink GTP tunnel end point information in the E-RABs To Be Setup Item of the E- , And downlink forwarding. For another example, the message that the anchor base station replies to the new base station may be a handover request message. And may include information for indicating that it is a response message to the terminal context request in the handover request message.

4) The new base station transmits the default downlink tunnel information

In the RAN-based paging process, in order to transmit the data buffered in the anchor base station through the new base station, the message transmission of three times in order to transmit the terminal context request of the new base station, the response thereto, and the acknowledgment message, Can increase the arena delay. In order to solve this problem, a new base station is initiated by RAN-based paging and transmits a paging message to a mobile station. Upon receiving an RRC connection resumption request message, a new base station requests a terminal context to an anchor base station. One) downlink PDUs including the default GTP tunnel endpoint information needed to transmit to the new base station

The anchor base station can operate in the same manner as in step 5 of FIG. And may be performed in the same manner as the operation of FIG. Or after receiving the terminal context information to the anchor base station, the MME and the GTP tunnel end point information for setting up the tunnel for all the E-RABs in the path switching process.

5) Multiple downlink tunnel information delivery

In the RAN-based paging process, in order to transmit the data buffered in the anchor base station through the new base station, the message transmission of three times in order to transmit the terminal context request of the new base station, the response thereto, and the acknowledgment message, Can increase the arena delay. In order to solve this problem, a new base station is initiated by RAN-based paging and transmits a paging message to a mobile station. Upon receiving an RRC connection resumption request message, a new base station requests a terminal context to an anchor base station. A plurality of GTP tunnel end point information necessary for transmitting downlink PDUs to a new base station

The anchor base station maps the E-RABs to be set up on the received downlink GTP tunnel endpoint. The anchor base station operates as in step 5 of FIG. If the number of received downlink GTP tunnel endpoints is greater than the number of E-RABs to map, it is possible to discard GTP tunnel endpoints that are not mapped. And may be performed in the same manner as the operation of FIG. Or if it is smaller than the E-RABs to be mapped, it can transmit GTP tunnel end point information for setting up a tunnel for all E-RABs in the path switching process after receiving the terminal context information to the anchor base station.

A non-access stratum (NAS) state and a light connection state transition method of a terminal

For example, a NAS state and a light connection state transition method of a terminal for a light connection state terminal can use the following methods individually or in combination.

1) When NAS recognizes a light connection status (terminal NAS: ECM-CONNECTED, terminal AS: RRC-IDLE)

For example, when a light connection is established to the terminal through RRC signaling, the terminal's RRC may indicate (inform) the NAS to it. In this case, the NAS of the terminal can consider the terminal as ECM-CONNECTED but in the RRC-IDLE state (or the NAS of the terminal is lightly connected). The NAS of the terminal maintains the NAS context.

When the terminal is triggered by the NAS signaling or MO data, the NAS / higher layer may instruct the RRC to transition to the connected state via the maintained / stored AS context.

In the Suspend / Resume procedure for the conventional NB-IoT terminal, the RRC Connection Resume Request is initiated by an instruction of the upper layer. In resuming the RRC connection at the instruction of the upper layer, the resume cause (resumeCause-r13) included in the RRC Connection Resume Request message has one of the following setup causes (EstablishmentCause-NB-r13).

ExceptionData, spare4, spare3, spare2, spare1} {mt-Access, mo-Signaling, mo-Data, mo-ExceptionData}

If it is intended to transit a lightly connected terminal to a connected state, the corresponding base station must recognize the cause to extract the terminal AS context from the anchor base station. For example, the upper layer and / or the RRC Connection Resume Request message may include a spare value of a setting cause (EstablishmentCause-NB-r13) for indicating a resume cause (resumeCause-r13) Or the like.

As another example for distinguishing and instructing the upper layer and / or the RRC Connection Resume Request message, the upper layer and / or the RRC Connection Resume Request message may specify the indication information for distinguishing the upper layer and / or the RRC Connection Resume Request message by defining a different field from the resume cause (resumeCause-r13). In this case, it is assumed that the cause of the resumption is mt-Access, mo-Signaling, mo-Data, mo-ExceptionData and that the resumption request message is triggered to transition the light connection terminal into the connection state. It is instructed to extract the context. As another example for distinguishing and instructing the upper layer and / or the RRC Connection Resume Request message, the upper layer and / or the RRC Connection Resume Request message includes a setting cause on the existing resume cause (resumeCause-r13) It is possible to designate and direct a field indicating that it is for instructing to extract the terminal AS context from the anchor base station.

2) When NAS recognizes the light connection status (terminal NAS: ECM-IDLE, terminal AS: RRC-IDLE)

As another example, when a light connection is established to the terminal through RRC signaling, the terminal's RRC may indicate (notify) it to the NAS. For example, the RRC can pass information to the NAS indicating a light connection status. In this case, the NAS of the terminal can consider the terminal as an ECM-IDLE and an RRC-IDLE state. It can be seen that the terminal is lightly connected (or the NAS of the terminal is lightly connected).

The NAS of the terminal may perform one or more of the following operations.

- The terminal maintains the NAS context.

- The terminal stores the NAS context.

- The terminal releases the NAS context but stores it. When NAS signaling or MO data is triggered in the terminal, it is reused / resumed / recovered / maintained / invoked.

- The terminal suspends the NAS context. When NAS signaling or MO data is triggered in the terminal, it is reused / resumed / recovered / maintained / invoked.

When the MS signaling or MO data is triggered, the MS / layer transmits it to the RRC. The RRC may be allowed to transition to a connected state via a maintained / stored AS context.

In the Suspend / Resume procedure for the conventional NB-IoT terminal, the RRC Connection Resume Request is initiated by an instruction of the upper layer. In resuming the RRC connection at the instruction of the upper layer, the resume cause (resumeCause-r13) included in the RRC Connection Resume Request message has one of the following setup causes (EstablishmentCause-NB-r13).

ExceptionData, spare4, spare3, spare2, spare1} {mt-Access, mo-Signaling, mo-Data, mo-ExceptionData}

If it is intended to transit a lightly connected terminal to a connected state, the corresponding base station must recognize the cause to extract the terminal AS context from the anchor base station. For example, the upper layer and / or the RRC Connection Resume Request message may include a spare value of a setting cause (EstablishmentCause-NB-r13) for indicating a resume cause (resumeCause-r13) Or the like.

As another example for distinguishing and instructing the upper layer and / or the RRC Connection Resume Request message, the upper layer and / or the RRC Connection Resume Request message may specify the indication information for distinguishing the upper layer and / or the RRC Connection Resume Request message by defining a different field from the resume cause (resumeCause-r13). In this case, it is assumed that the cause of the resumption is mt-Access, mo-Signaling, mo-Data, mo-ExceptionData and that the resumption request message is triggered to transition the light connection terminal into the connection state. It is instructed to extract the context. As another example for distinguishing and instructing the upper layer and / or the RRC Connection Resume Request message, the upper layer and / or the RRC Connection Resume Request message includes a setting cause on the existing resume cause (resumeCause-r13) It is possible to designate and direct a field indicating that it is for instructing to extract the terminal AS context from the anchor base station.

3) If NAS does not recognize the light connection status (terminal NAS: ECM-CONNECTED, terminal AS: RRC-IDLE)

As another example, when a light connection is established to the terminal through RRC signaling, the terminal's RRC may not indicate (notify) it to the NAS. In this case, the NAS of the terminal considers the terminal to be in the ECM-CONNECTED state. The AS (or RRC) of the terminal can be considered as the RRC-IDLE state. It can be seen that the terminal (or AS or RRC of the terminal) is in a light connection state. When the NAS signaling or MO data is triggered, the NAS / higher layer forwards it to the corresponding SRB or DRB. Once the data is transferred to the SRB / DRB, the RRC may transition to the connected state via the maintained / stored AS context.

As described above, the present invention has an effect of processing RAN-based paging by effectively utilizing the terminal context for a terminal having a light connection.

6 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.

Referring to FIG. 6, a base station 1000 according to another embodiment includes a control unit 1010, a transmission unit 1020, and a reception unit 1030.

The control unit 1010 provides a method and an apparatus for a new base station to effectively use a terminal context when a light connection terminal necessary for performing the present invention described above performs cell selection on a base station cell other than an anchor base station Thereby controlling the overall base station operation.

The transmitting unit 1020 and the receiving unit 1030 are used to transmit and receive signals, messages, and data necessary for carrying out the present invention to and from the terminal.

7 is a diagram illustrating a configuration of a user terminal according to another embodiment of the present invention.

Referring to FIG. 7, the user terminal 1100 according to another embodiment includes a receiving unit 1110, a control unit 1120, and a transmitting unit 1130.

The receiving unit 1110 receives downlink control information, data, and messages from the base station through the corresponding channel.

The controller 1120 also provides a method and an apparatus for a new base station to effectively utilize a terminal context when a light connection terminal necessary for performing the above-described present invention performs cell selection on a base station cell other than an anchor base station Thereby controlling the overall operation of the terminal.

The transmitter 1130 transmits uplink control information, data, and a message to the base station through the corresponding channel.

The standard content or standard documents referred to in the above-mentioned embodiments constitute a part of this specification, for the sake of simplicity of description of the specification. Therefore, it is to be understood that the content of the above standard content and some of the standard documents is added to or contained in the scope of the present invention, as falling within the scope of the present invention.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (1)

A method for processing a terminal context,
Selecting a light connection terminal to a base station cell that is not an anchor base station; And
And the new base station effectively utilizing the terminal context.

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