KR20140137277A - Methods and apparatuses for RRC Connection Re-establishment/Re-configuration - Google Patents

Abstract

The present invention relates to a method and an apparatus for re-setting and re-configuration of wireless resources through small cells, when a terminal detects radio link failure (RLF), in an environment in which macro cells and small cells are overlaid through individual eNBs. More specifically, in the present invention, provided are a method and an apparatus where the apparatus detects RLFs on cells related to a first base station and includes a step of resuming the transmission of signaling and data through cells related to a second base station.

Description

Methods and apparatuses for RRC connection re-establishment / Re-configuration < RTI ID = 0.0 >

The present invention relates to a method and apparatus for reestablishing a radio resource through a small cell when an MS detects an RLF (Radio Link Failure) from a macro cell in an environment in which macrocells and small cells are overlaid on each eNB .

A method for processing an RLF in a terminal according to the present invention comprises the steps of: configuring a dual connection with a first base station and a second base station; detecting, when an RLF occurs in a cell associated with the first base station, And resuming signaling and data transmission through the associated cell.

1 is a diagram showing an uplink layer 2 structure (a Layer 2 Structure for UL with CA configured) in a CA configuration.
2 is a diagram illustrating a downlink layer 2 structure (a Layer 2 Structure for DL with CA configuration) in a CA configuration.
3 is a diagram illustrating an RRC Connection Re-establishment procedure.
4 is a diagram showing a network configuration scenario example 1 for the present invention.
5 is a diagram showing a network configuration scenario example 2 for the present invention.
6 is a diagram showing a network configuration scenario example 3 for the present invention.
7 is a diagram illustrating an example of a layer 2 protocol structure for transmission of control plane data for the present invention.
8 is a diagram illustrating an example of a protocol structure for the present invention.
FIG. 9 is a diagram illustrating a configuration of a base station according to another embodiment.
10 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 numerals whenever 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.

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) a device itself providing a megacell, a macrocell, a microcell, a picocell, a femtocell, or a small cell in relation to a wireless region, or ii) 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 megacell, a macrocell, a microcell, a picocell, a femtocell, a small cell, an RRH, an antenna, an RU, a low power node (LPN), a point, an eNB, Quot;

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, the uplink and downlink are configured on the basis of one carrier or carrier pair to form a standard. 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 transmission / reception 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 multiplex transmission / reception point to a terminal, and an uplink refers to a communication or communication path from a terminal to a multiplex 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 a PDSCH, 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.

1 is a diagram showing an uplink layer 2 structure (a Layer 2 Structure for UL with CA configured) in a CA configuration.

2 is a diagram illustrating a downlink layer 2 structure (a Layer 2 Structure for DL with CA configuration) in a CA configuration.

Small cells using low power nodes are being considered as a means to cope with mobile traffic explosion. A low power node represents a node using lower transmit (Tx) power than a typical macro node.

Prior to 3GPP Release 11, carrier aggregation (CA) technology was able to build a small cell using a low power RRH (Remote Radio Head), which is a geographically dispersed antenna within macro cell coverage.

However, in order to apply the CA technology, the macro cell and the RRH cell must be configured to be scheduled under the control of one eNB, and an ideal backhaul between the macro cell node and the RRH is required. An ideal backhaul is a backhaul that has very high throughput and very little delay, such as a dedicated point-to-point connection using optical fiber, LOS (line of sight) microware. In contrast, a backhaul exhibiting relatively low throughput and large delay, such as Digital Subscriber Line (xDSL) and Non-LOS microwave, is called a non-ideal backhaul.

Through the CA technology described above, a plurality of serving cells could be merged to service a UE (User Equipment). That is, a plurality of serving cells can be configured for a UE in the RRC (Radio Resource Control) CONNECTED state. When an ideal backhaul is established between the macro cell node and the RRH, the macro cell and the RRH cell together constitute serving cells, Could.

When the CA technology is configured, the UE may only have one RRC connection with the network.

One serving cell provides NAS mobility information (eg TAI: Tracking Area Identity) in RRC connection establishment / re-establishment / handover, and one serving cell in the RRC connection reset / It provides a security input. These cells are called PCell (Primary Cell). PCell can only be changed with the handover procedure.

Depending on the UE capabilities, SCells (Secondary Cells) can be configured with the serving cell as the PCells. The addition and removal of SCells are performed by the RRC. The multiple carrier attributes of the physical layer in the single eNB-based CA described above only affected the MAC layer (Medium Access Control). The MAC layer has one independent Hybrid Automatic Retransmission request (HARQ) entity for each serving cell in the uplink and downlink. Each HARQ entity processes a data stream of a component carrier (CC).

Radio Link Failure

The UE detects an RLF (Radio Link Failure) in the following cases.

- When out-of-synchronization of PCell occurs from the physical layer

- Random access problem occurs in MAC layer

- When the maximum number of retransmissions is reached in the RLC layer

3 is a diagram illustrating an RRC Connection Re-establishment procedure.

When the UE detects the RLF, it stores the RLF information in the VarRLF-Report. If AS security is not activated, the terminal leaves the RRC Connected state. That is, it moves directly to the RRC IDLE state. Otherwise, if AS security is activated, RRC Connection Re-establishment procedure is executed. RRC Connection Re-establishment succeeds only if the associated cell is ready, that is, if it has a valid UE context. If the E-UTRAN accepts Re-establishment, the SRB1 (Signaling Radio Bearer1) operation is resumed while other radio bearers are suspended (while the other radio bearers remain suspended). The RRC connection re-establishment procedure is initiated not only for RLF but also for handover failure or RRC connection reconfiguration failure. When the RRC connection re-establishment procedure is started by detecting the RLF or the like as described above, the UE suspends all radio bearers except SRB0. If SCell (s) is configured, release SCell (s). After selecting the appropriate cell by performing the cell selection process, the UE transmits an RRC Connection Reestablishment Request message. The UE receiving the RRC Connection Reestablishment message after the RRC Connection re-establishes the PDCP for SRB1. The UE re-establishes the RLC for SRB1. The UE performs the radio resource configuration procedure according to the received radio resource configuration dedicated radio resource configuration information. The UE resumes SRB1. FIG. 3 shows an RRC Connection Re-establishment procedure.

In a conventional single eNB-based CA, a terminal connected to multiple cells detects RLF for PCell, but does not detect RLF for SCell. PCell could use CQI and measurement results to detect radio link problems in SCell, and PCell could deactivate / remove SCell if there was a radio link problem in SCell, which did not detect RLF for SCell. When the terminal detects RLF for PCell and performs RRC Connection Re-establishment procedure, it releases SCell. After that, the UE sets up the SCell addition through the RRC Connection Re-configuration procedure so that it can use the new SCell.

In a conventional single eNB-based CA, when a UE transmits data through a plurality of cells, when the UE detects RLF in the PCell, the SCELL is released and a RRC connection Re-establishment procedure is initiated.

SUMMARY OF THE INVENTION The present invention, which has been devised to solve the above problems, provides a method and apparatus for a UE configured to use radio resources provided by one or more eNBs connected through a non-ideal backhaul, wherein RLFs are generated in a PCell (or macrocell or macro eNB cell) (Or small cell or small cell eNB), data can be transmitted through SCell (or small cell or small cell eNB), signaling is performed through SCell (or small cell or small cell eNB) capable of data transmission to effectively resume connection, So that the transmission can be resumed.

4 is a diagram showing a network configuration scenario example 1 for the present invention.

As shown in FIG. 4, the macrocell and the small cells have the same carrier frequency F1 and are connected through a non-ideal backhaul between the macro cell node eNB and the small cell node eNB. Small cells are built into an overlaid macro network. An outdoor small cell environment and a small cell cluster can be considered.

5 is a diagram showing a network configuration scenario example 2 for the present invention.

As shown in FIG. 5, macrocells and small cells have different carrier frequencies F1 and F2, and non-ideal backhaul between a macro cell node (eNB) and a small cell node (eNB) Lt; / RTI > Small cells are built into an overlaid macro network. An outdoor small cell environment or an indoor small cell environment and a small cell cluster are considered.

6 is a diagram showing a network configuration scenario example 3 for the present invention.

Only small cells with only one or more carrier frequencies are present as shown in FIG. 6, and are connected through non-ideal backhaul between small cell nodes (eNB). Indoor small cell environments and small cell clusters are considered.

7 is a diagram illustrating an example of a layer 2 protocol structure for transmission of control plane data for the present invention.

As shown in FIG. 7, in the scenario of FIG. 4 and FIG. 5, the UE may perform the control of the macro cell eNB through one or more small cell eNBs, or between the macro cell eNB and one or more small cell eNBs , Or via collaboration between small cell eNBs in the scenario of Fig. 6. That is, for control plane data transmission, the UE establishes one RRC connection with the macrocell eNB, and can configure macrocell eNB, small cell eNB, and one or more Signaling Radio Bearers (SRBs).

In the present invention, the macrocell eNB, the small cell eNB, and one or more Signaling Radio Bearers (SRBs) are shown as examples in FIG. 7, but the present invention is not limited to the structure of FIG. That is, the UE can transmit an RRC message to the macro cell eNB using two (one or more) base station radio resources.

As another example of the present invention, in the scenario of FIGS. 4 and 5, the UE may transmit the control plane data through the macro cell eNB or through one small cell eNB in the scenario of FIG. In order to transmit control plane data, the UE sets up one or more Signaling Radio Bearers (SRBs) by setting only one RRC connection with the macrocell eNB of FIG. 4 and FIG. 5 or the small cell eNB of FIG. can do.

As another example of the present invention, in the scenarios of FIGS. 4 and 5, the UE may communicate with one or more small cell eNBs under control of a macrocell eNB, or through cooperation between macrocell eNBs and one or more small cell eNBs, or It is possible to transmit the user plane data through cooperation between the small cell eNBs in the scenario of Fig. That is, for control plane data transmission, the UE sets up one RRC connection with the macro cell eNB, and can configure one or more DRBs (Data Radio Bearers) with the macro cell eNB and the small cell eNB.

As another example of the present invention, in the scenarios of FIGS. 4 and 5, only macrocell eNBs are used either through cooperation between macrocell eNBs and one or more small cell eNBs, or between small cell eNBs in the scenario of FIG. 6 The user plane data can be transmitted through only the small cell eNB. That is, for control plane data transmission, the UE establishes one RRC connection with the macrocell eNB, and can configure one or more DRBs only through the macrocell eNB. And / or one or more DRBs through only the small cell eNB.

In FIGS. 4, 5 and 6, the eNB having the primary responsibility for maintaining the RRC context of the UE and terminating the S1-MME interface may be referred to as an anchor eNB (or a Primary Cell eNB or a master base station). Since the macrocell eNB of FIGS. 4 and 5 serves as the anchor eNB, the macrocell eNB may mean anchor eNB in the embodiment of the present invention.

4, 5 and 6, an eNB providing additional radio resources for a UE may be referred to as an assisting eNB (or Secondary Cell eNB). The small cell eNB of FIGS. 4 and 5 plays the role of the assisting eNB, so the small cell eNB in the embodiment of the present invention can mean an assisting eNB.

8 is a diagram illustrating an example of a protocol structure for the present invention.

8 shows an example of a protocol structure for using radio resources provided by one or more eNBs connected through a non-ideal backhaul. FIG. 8A shows a structure in which only a macro cell eNB (or an anchor eNB) has an RRC entity for a UE, FIG. 8B shows a structure in which a macro cell eNB (or an anchor eNB) (Or assisting eNB) has an RRC entity for the UE. 8 (b), the RRC entity of the small cell eNB (or the assisting eNB) does not have the entire RRC function, but when the UE detects the RLF in the PCell (or the macrocell eNB or the anchor eNB) Function.

Although Fig. 8 is shown as an embodiment in the present invention, the present invention is not limited to the structure of Fig.

When the UE detects an RLF in a macro-cell eNB (or an anchor eNB) radio link (for example, out-of-synchronization occurs for PCell from the physical layer, a random access problem occurs in the MAC layer, Cell eNB (or Assisting eNB) radio link, if a UE using radio resources provided by one or more eNBs connected through a non-ideal backhaul is capable of data transmission over a small-cell eNB (or Assisting eNB) ) A method of handling signaling over a wireless link is described in detail.

Method 1: Anchor eNB While maintaining PCell Bearer  Reconstruction / Reset

(Or an anchor eNB) and a small cell eNB (or an assisting eNB) even if the RLF is detected due to out-of-synchronization occurrence from the physical layer to the PCELL in the macrocell eNB (or anchor eNB) (Or the anchor eNB) and the macro cell eNB (or the anchor eNB), even if RLF is detected due to out-of-synchronization occurrence from the physical layer to the PCell in the macrocell eNB When a UE configured to transmit data through an eNB (or an assisting eNB) is capable of transmitting data through a small cell eNB (or an assisting eNB) (e.g., when data is being transmitted to or synchronized with a small cell eNB, (Or the serving cell of the small cell eNB), the RLF is not detected, the radio channel quality of the small cell eNB (or the serving cell of the small cell eNB) is higher than a certain level, etc.) The signaling for transmitting (or processing) a radio bearer configured to transmit data only through all radio bearers or macrocell eNBs (or anchor eNBs or PCells) through the small cell eNB (or the assisting eNB) is referred to as the small cell eNB ) To the macro cell eNB (or the anchor eNB). To this end, if there is a radio bearer configured to transmit data only through the macrocell eNB (or the anchor eNB or PCell), the UE may suspend all radio bearers configured to transmit data only via the macrocell eNB (or anchor eNB or PCell) And signaling for processing the radio bearer through the small cell eNB (or Assisting eNB) can be transmitted to the macro cell eNB (or the anchor eNB) through the small cell eNB (or Assisting eNB).

For radio bearers configured to transmit data via the macro cell eNB (or the anchor eNB or PCell) and the small cell eNB (or the assisting eNB), the UE stops the uplink transmission via the macrocell eNB (or the anchor eNB or PCell) And continue data transmission through the small cell eNB (or Assisting eNB). Or macro-cell eNB (or anchor eNB or PCell) and a small-cell eNB (or Assisting eNB).

As an example of signaling for transmitting (or processing) a radio bearer configured to transmit data only through all the above radio bearers or macrocell eNBs (or anchor eNBs or PCell) through the small cell eNB (or the assisting eNB) Can be delivered via the RRC Connection Reestablishment Request message. To this end, the UE transmits a new RRC Connection Reestablishment Request message to the RRC Connection Reestablishment Request message in order to process a radio bearer configured to transmit data only through all radio bearers or macrocell eNBs (or anchor eNBs or PCell) through the small cell eNB (or Assisting eNB) The cause value or macro cell eNB (or anchor eNB or PCell) RLF may be defined and included to define a new cause value. Alternatively, the macro cell eNB (or the anchor eNB) receiving the RRC Connection Reestablishment Request message from the UE via the small cell eNB (or the assisting eNB) requests that the radio bearer be processed through the small cell eNB (or the assisting eNB) It can be recognized.

The RRC Connection Reestablishment Request message can be transmitted to the small cell eNB (or the assisting eNB) by SRB0. The small cell eNB (or Assisting eNB) receiving the RRC Connection Reestablishment Request message by the using CCCH logical channel (SRB0) transmits the received RRC Connection Reestablishment Request message to the macro cell eNB (or the anchor eNB) and the small cell eNB (Or an anchor eNB) through an Xx interface (or an X2 interface) between an Assisting eNB. Alternatively, the RRC Connection Reestablishment Request message may be transmitted to the small cell eNB and the small cell eNB through a signaling radio bearer (e.g., SRB1 or SRB2) for transmission of the control plane data. eNB (or Assisting eNB) and may be transmitted to the macro cell eNB. This is possible by configuring one or more Signaling Radio Bearers (SRBs) with the macrocell eNB and the small cell eNB for the control plane data transmission as described above. Even if the UE detects the RLF on the macro cell eNB (or the anchor eNB), the UE transmits the signaling to the small cell eNB through the signaling radio bearer (eg SRB1 or SRB2) configured through the macro cell eNB and the small cell eNB, The cell eNB can forward to the macro cell eNB.

The macro cell eNB (or the anchor eNB) receiving the RRC Connection Reestablishment Request message from the UE through the small cell eNB (or the assisting eNB) is configured to transmit data only through all the radio bearers or the macro cell eNB (or the anchor eNB or PCell) An RRC Connection Reestablishment message for configuring the radio bearer to be transmitted through the small cell eNB (or Assisting eNB) may be transmitted to the UE via the small cell eNB (or Assisting eNB). The RRC Connection Reestablishment message is transmitted to a small cell eNB (or an Assisting eNB (or an eNB) via a radio resource configuration information element (radio resource configuration information element) through a radio bearer or macrocell eNB (or an anchor eNB or PCell) (For example, small cell eNB SCell index (or small cell eNB ID information or small cell eNB cell index), or SCell radio resource configuration information (or small cell eNB radio resource configuration information ) Includes SCellindex (small cell eNB identification information or small cell eNB cell index), DRB configuration information). Upon receiving the RRC Connection Reestablishment message, the UE sends an RRC Connection Reestablishment Complete message to the macro cell eNB (or the anchor eNB) through the small cell eNB (or the assisting eNB) and the macro cell eNB (or the anchor eNB) eNB) to re-establish RLC and PDCP for a radio bearer configured to transmit data only through all radio bearers or macrocell eNBs (or anchor eNBs or PCell) that have been suspended, It is possible to configure the radio bearer configured to transmit data only through all the radio bearers or macrocell eNBs (or the anchor eNBs or PCell) that have been transmitted through the small cell eNB to resume the data transmission. To this end, the RRC Connection Reconfiguration message includes a radio bearer configured to transmit data through all radio bearers or macrocell eNBs (or an anchor eNB or PCell) through a radio resource configuration information element (radio resource configuration information element) (Eg, small cell eNB identification information or small cell eNB cell index), or SCell radio resource configuration information (or small cell eNB radio resource configuration Information includes SCellindex (small cell eNB identification information or small cell eNB cell index), DRB configuration information). Alternatively, configuration information (e.g., DRB configuration information) for processing a radio bearer configured to transmit data only through all radio bearers or macrocell eNBs (or anchor eNBs or PCell) through the small cell eNB (or Assisting eNB) (Small cell eNB identification information or small cell eNB cell index) is included in the SCELL radio resource configuration information (or the small cell eNB radio resource configuration information) including the small cell eNB SCellindex (small cell eNB identification information or small cell eNB cell index) (Including the DRB configuration information), the UE resets the RLC and PDCP for the radio bearers configured to transmit data only through all radio bearers or macrocell eNBs (or anchor eNBs or PCell) that have been suspended (or anchor eNB or PCell) to all the radio bearers or macrocell eNBs that have been suspended That can be configured to resume the transfer of data to process the radio bearer is configured with the small cell eNB.

Another example of signaling for transmitting (or processing) a radio bearer configured to transmit data only through all of the above radio bearers or macrocell eNBs (or anchor eNB or PCell) through the small cell eNB (or the assisting eNB) Signaling can be delivered via a measurement report. To this end, the UE may define new information in the MeasResults information element of the measurement report, or define a new information element to process the radio bearer through the small cell eNB (or Assisting eNB). The above-mentioned measurement report can be transmitted to the macro cell eNB (or the anchor eNB) through the small cell eNB (or the assisting eNB). This is possible by configuring one or more Signaling Radio Bearers (SRBs) with the macrocell eNB and the small cell eNB for the control plane data transmission as described above. Even if the UE detects the RLF on the macro cell eNB (or the anchor eNB), the UE transmits the signaling to the small cell eNB through the signaling radio bearer (eg SRB1 or SRB2) configured through the macro cell eNB and the small cell eNB, Cell eNB.

(Or processes) a radio bearer configured to transmit data only through all radio bearers or macrocell eNBs (or anchor eNBs or PCell) from the UE via the small cell eNB (or Assisting eNB) through the small cell eNB (or Assisting eNB) The macrocell eNB (or the anchor eNB) receiving the measurement report including the signaling for transmitting the measurement report to the small cell eNB (or the anchor eNB) transmits the radio bearer configured to transmit data only through all the radio bearers or the macrocell eNB (or the anchor eNB or PCell) Assisting eNB) through the small cell eNB (or Assisting eNB) to the UE via the RRC Connection Reconfiguration message. The RRC Connection Reconfiguration message is transmitted to the small cell eNB (or the Assisting eNB (or the Assisting eNB) via the radio resource configuration information element (radio resource configuration information element) (E.g., small cell eNB identification information or small cell eNB cell index) or SCell radio resource configuration information (or small cell eNB radio resource configuration information) in the DRB configuration information, SCellindex (small cell eNB identification information or small cell eNB cell index), and DRB configuration information). Upon receiving the RRC Connection Reconfiguration message, the UE re-establishes the RLC and PDCP for the radio bearer configured to transmit data only through all the radio bearers or macrocell eNBs (or the anchor eNBs or PCell) that have been suspended, The radio bearer configured to transmit data only via the radio bearer or the macrocell eNB (or the anchor eNB or PCell) can be configured to process through the small cell eNB to resume the data transmission.

Another example of signaling for transmitting (or processing) a radio bearer configured to transmit data only through all of the above radio bearers or macrocell eNBs (or anchor eNB or PCell) through the small cell eNB (or the assisting eNB) The signaling may be delivered via an existing RRC signaling message (or procedure), or by defining a new RRC signaling message (or procedure). In order to do this, the UE transmits a macrocell eNB (or an anchor eNB) to all the radio bearers or macrocell eNBs (or an anchor eNB or PCell (or an anchor eNB or an anchor eNB) to a new RRC signaling message (Or Assisting eNB) to process the radio bearer configured to transmit data only through the small cell eNB (or Assisting eNB). The existing RRC signaling message or the new RRC signaling message can be transmitted to the macro cell eNB (or the anchor eNB) through the small cell eNB (or the assisting eNB). This is possible by configuring one or more Signaling Radio Bearers (SRBs) with the macrocell eNB and the small cell eNB for the control plane data transmission as described above. Even if the UE detects the RLF on the macro cell eNB (or the anchor eNB), the UE transmits the signaling to the small cell eNB through the signaling radio bearers (eg SRB1 and / or SRB2) configured through the macro cell eNB and the small cell eNB To the macro cell eNB.

(Or processes) a radio bearer configured to transmit data only through all radio bearers or macrocell eNBs (or anchor eNBs or PCell) from the UE via the small cell eNB (or Assisting eNB) through the small cell eNB (or Assisting eNB) (Or the anchor eNB) that has received the new RRC signaling message is configured to transmit data only through all the radio bearers or macrocell eNBs (or the anchor eNB or PCell), including the signaling for transmitting the new RRC signaling message An RRC Connection Reconfiguration message for configuring the RB to be transmitted through the small cell eNB (or Assisting eNB) may be transmitted to the UE via the small cell eNB (or Assisting eNB). The RRC Connection Reconfiguration message is transmitted to the small cell eNB (or the Assisting eNB (or the Assisting eNB) via the radio resource configuration information element (radio resource configuration information element) (E.g., small cell eNB identification information or small cell eNB cell index) or SCell radio resource configuration information (or small cell eNB radio resource configuration information) in the DRB configuration information, SCellindex (small cell eNB identification information or small cell eNB cell index), and DRB configuration information). Upon receiving the RRC Connection Reconfiguration message, the UE re-establishes the RLC and PDCP for the radio bearer configured to transmit data only through all the radio bearers or macrocell eNBs (or the anchor eNBs or PCell) that have been suspended, The radio bearer configured to transmit data only via the radio bearer or the macrocell eNB (or the anchor eNB or PCell) can be configured to process through the small cell eNB to resume the data transmission.

Method 2: Assisting eNB in RRC connection  reset

(Or an anchor eNB) and a small cell eNB (or an assisting eNB) even if the RLF is detected due to out-of-synchronization occurrence from the physical layer to the PCELL in the macrocell eNB (or anchor eNB) (Or the anchor eNB) and the macro cell eNB (or the anchor eNB), even if RLF is detected due to out-of-synchronization occurrence from the physical layer to the PCell in the macrocell eNB When a UE configured to transmit data through an eNB (or an assisting eNB) is capable of transmitting data through a small cell eNB (or an assisting eNB) (e.g., when data is being transmitted to or synchronized with a small cell eNB, (Or the serving cell of the small cell eNB), the RLF is not detected, the radio channel quality of the small cell eNB (or the serving cell of the small cell eNB) is higher than a certain level, etc.) Signaling can be performed to reset the RRC connection to the small cell eNB (or the assisting eNB). For this purpose, the UE may suspend all radio bearers except for SRB0 and forward the signaling to the small cell eNB to reset the RRC connection. Or if there is a radio bearer configured to transmit data only via the macrocell eNB (or the anchor eNB or PCell), the UE only suspends the radio bearer configured to transmit data only via the macrocell eNB (or the anchor eNB or PCell) The data transmission can be continued through the small cell eNB (or the assisting eNB) for the radio bearers configured to transmit data via the macro cell eNB (or the anchor eNB or PCell) and the small cell eNB (or the assisting eNB). For example, if the UE has configured macrocell eNBs and small cell eNBs and SRB1 signaling radio bearers for control plane data transmission as described above, SRB1 may continue to transmit data through the small cell have.

As an example of the signaling for reestablishing the RRC connection with the small cell eNB (or the assisting eNB), the above signaling message can be transmitted through the RRC Connection Reestablishment Request message. To this end, the UE may define a new cause value for indicating the macro cell eNB (or the anchor eNB or PCell) RLF in the Reestablishment Cause of the RRC Connection Reestablishment Request message. Alternatively, the small cell eNB (or the assisting eNB) receiving the RRC Connection Reestablishment Request message from the UE configured to transmit data via the macro cell eNB (or the anchor eNB) and the small cell eNB (or the assisting eNB) (Or anchor eNB or PCell) RLF to the RRC connection. The RRC Connection Reestablishment Request message includes a C-RNTI, a Physical Cell ID (PCI), and a short MAC-I information element used in a macro cell eNB (or an anchor eNB or PCell).

The RRC Connection Reestablishment Request message can be transmitted to the small cell eNB (or the assisting eNB) by SRB0. The small cell eNB (or the assisting eNB) receiving the RRC Connection Reestablishment Request message through SRB0 may forward the RRC Connection Reestablishment message for re-establishing (or reconfiguring) the RRC Connection to the UE. When the small cell eNB (or Assisting eNB) receives the RRC Connection Reestablishment Request message, the small cell eNB (or the assisting eNB) transmits the macro cell eNB (or the assisting eNB) via the Xx interface (or X2 interface) between the macro cell eNB (Or interrogate) an associated UE context from an anchor eNB. Alternatively, the small cell eNB (or the assisting eNB) may transmit the RRC Connection Reestablishment Request message through the Xx interface (or X2 interface) between the macro cell eNB (or the anchor eNB) and the small cell eNB (or the assisting eNB) Receives the associated UE context from the macro-cell eNB (or anchor eNB) Received when configuring to transmit data via the macro cell eNB (or anchor eNB or PCell) and the small cell eNB (or Assisting eNB), or interrogated [e. (Depending on the indication from the UE or the decision of the small cell eNB).

 The UE context includes an MME UE S1AP ID, UE Security Capabilities, AS Security Information, UE Aggregate Maximum Bit Rate Subscriber Profile ID for RAT / Frequency priority, E-RAB QoS parameters, Tunnel endpoint, (Including radio resource configuration information, radio bearer information configured to transmit data only via macrocell eNB (or anchor eNB or PCell), radio bearer information configured to transmit data only via macrocell eNB (or anchor eNB or PCell) The radio bearer indication information configured to transmit data only through the macro cell eNB (or the anchor eNB or PCell) may be included in the DRB configuration information).

The RRC Connection Reestablishment message includes a radio bearer configured to transmit data via only radio bearer information or macrocell eNB (or anchor eNB or PCell) through a radio resource configuration information element (radio resource configuration information element) through a small cell eNB And the like.

Upon receiving the RRC Connection Reestablishment message, the UE resumes SRB1 that was suspended. The UE may update the KeNB key and derive three AS keys to reactivate the AS security. After the AS secret re-activation, the UE sends an RRC Connection Reestablishment Complete message through the resumed SRB1. The UE that has received the RRC Connection Reestablishment message sends an RRC Connection Reestablishment Complete message to the Small Cell eNB (or Assisting eNB), and the Small Cell eNB (or Assisting eNB) performs an RRC Connection Reconfiguration procedure to transmit all suspended radio bearers or macro cells it re-establishes the RLC and PDCP for a radio bearer configured to transmit data only through the eNB (or the anchor eNB or PCell) and re-establishes the data only through all radio bearers or macrocell eNBs (or anchor eNBs or PCell) The radio bearer configured to transmit can be resumed. Alternatively, upon receiving the RRC Connection Reestablishment message, the UE may re-establish the RLC and PDCP for a radio bearer configured to transmit data only through all radio bearers or macrocell eNBs (or anchor eNBs or PCell) that have been suspended. And the radio bearer configured to transmit data only through all the radio bearers or macrocell eNBs (or the anchor eNBs or PCell) that have been suspended can be configured to process through the small cell eNB to resume the data transmission.

As another example of signaling for resetting (or triggering a reset) the RRC Connection to the small cell eNB (or Assisting eNB), the above signaling can be conveyed through a measurement report. To this end, the UE may define new information in the MeasResults information element of the measurement report, or define a new information element to re-establish the RRC connection with the small cell eNB (or the assisting eNB) so that all radio bearers or macrocell eNBs (E. G., PCell) only through the small cell eNB (or Assisting eNB).

A small cell eNB (or an assisting eNB) that has received a measurement report including signaling for re-establishing (or triggering a reset) an RRC connection from a UE to a small cell eNB (or an assisting eNB) ) To reconfigure the RRC connection and transmit an RRC Connection Reconfiguration message to the UE for processing the radio bearer through the small cell eNB (or the assisting eNB). The RRC Connection Reconfiguration message is transmitted to the small cell eNB (or the Assisting eNB (or the Assisting eNB) via the radio resource configuration information element (radio resource configuration information element) ) To be processed via the network.

The small cell eNB (or Assisting eNB) re-establishes RLC and PDCP for a radio bearer configured to transmit data only through all radio bearers or macrocell eNBs (or anchor eNBs or PCell) that have been suspended from the UE that received the RRC Connection Reconfiguration message (or Assisting eNB) configured to transmit data only through all radio bearers or macrocell eNBs (or anchor eNBs or PCells) that have been suspended and re-established.

Upon receiving the measurement report, the small cell eNB (or the assisting eNB) resets the RRC connection to the small cell eNB (or the assisting eNB) and transmits the UE context information necessary for processing the radio bearer through the small cell eNB (or the assisting eNB) (Or anchor eNB) through the Xx interface (or X2 interface) between the macro cell eNB (or the anchor eNB) and the small cell eNB (or the assisting eNB). Alternatively, the small cell eNB (or the assisting eNB) transmits the measurement report to the small cell eNB (or the assisting eNB) via the Xx interface (or X2 interface) between the macro cell eNB (or the anchor eNB) receives an associated UE context from an eNB (or an anchor eNB) Received when configuring to transmit data via the macro cell eNB (or anchor eNB or PCell) and the small cell eNB (or Assisting eNB), or interrogated [e. (Depending on the indication from the UE or the decision of the small cell eNB).

 The UE context includes an MME UE S1AP ID, UE Security Capabilities, AS Security Information, UE Aggregate Maximum Bit Rate Subscriber Profile ID for RAT / Frequency priority, E-RAB QoS parameters, Tunnel endpoint, (Including radio resource configuration information, radio bearer information configured to transmit data only via macrocell eNB (or anchor eNB or PCell), radio bearer information configured to transmit data only via macrocell eNB (or anchor eNB or PCell) The radio bearer indication information configured to transmit data only through the macro cell eNB (or the anchor eNB or PCell) may be included in the DRB configuration information).

As another example of signaling for resetting (or triggering a reset) the RRC Connection to the small cell eNB (or Assisting eNB) described above, the signaling may be an existing RRC signaling message (or procedure), or a new RRC signaling message The UE may define a new RRC signaling message (or procedure) through a new information element of the existing RRC signaling message (or procedure), and transmit the RRC Connection (or procedure) message to the small cell eNB And the radio bearer can be processed through the small cell eNB (or the assisting eNB).

The small cell eNB (or Assisting eNB) receiving the signaling for re-establishing the RRC connection (or triggering the reset) from the UE to the small cell eNB (or the assisting eNB) transmits the RRC The connection can be reconfigured to forward the RRC Connection Reconfiguration message to the UE for processing the radio bearer through the small cell eNB (or Assisting eNB). The RRC Connection Reconfiguration message is transmitted to the small cell eNB (or the Assisting eNB (or the Assisting eNB) via the radio resource configuration information element (radio resource configuration information element) ) To be processed via the network.

The UE receiving the RRC Connection Reconfiguration message through the small cell eNB (or Assisting eNB) transmits RLC and PDCP to the radio bearers configured to transmit data only through all radio bearers or macrocell eNBs (or anchor eNBs or PCell) that have been suspended. It may reconfigure to process through the small cell eNB (or Assisting eNB) a radio bearer that is configured to re-establish and transmit data only through all radio bearers or macrocell eNBs (or anchor eNB or PCell) that have been suspended.

When the small cell eNB (or the assisting eNB) receives the signaling for resetting the RRC connection (or triggering the resetting) to the small cell eNB (or the assisting eNB), the small cell eNB (or the assisting eNB) (Or an assisting eNB) between the macro cell eNB (or the anchor eNB) and the small cell eNB (or the assisting eNB) by processing the radio bearer through the small cell eNB (or the assisting eNB) (Or anchor eNB) through the macro cell eNB (or anchor eNB). Alternatively, the small cell eNB (or the assisting eNB) transmits the macro cell eNB (or the assisting eNB) via the Xx interface (or X2 interface) between the macro cell eNB (or the anchor eNB) and the small cell eNB (Or the anchor eNB) receives an associated UE context, Received when configuring to transmit data via the macro cell eNB (or anchor eNB or PCell) and the small cell eNB (or Assisting eNB), or interrogated [e. (Depending on the indication from the UE or the decision of the small cell eNB).

 The UE context includes an MME UE S1AP ID, UE Security Capabilities, AS Security Information, UE Aggregate Maximum Bit Rate Subscriber Profile ID for RAT / Frequency priority, E-RAB QoS parameters, Tunnel endpoint, (Including radio resource configuration information, radio bearer information configured to transmit data only via macrocell eNB (or anchor eNB or PCell), radio bearer information configured to transmit data only via macrocell eNB (or anchor eNB or PCell) The radio bearer indication information configured to transmit data only through the macro cell eNB (or the anchor eNB or PCell) may be included in the DRB configuration information).

In the present invention, when a terminal connected to a plurality of cells generates an RLF in one cell, the RLF information of the corresponding cell is transmitted through another serving cell, thereby enabling to recover the RLF more quickly. In addition, when RLF occurs in one cell, it does not erase all the connected cell information, suspends the cell without any problem, and when the restoration of the cell in which the RLF is generated is completed, the information about the remaining cell is transmitted to the base station, So that it can be recovered quickly.

The present invention is applicable to a UE configured to use radio resources provided by one or more eNBs connected through a non-ideal backhaul, even if an RLF occurs in a PCell (or macrocell or macro eNB cell) eNB), it is possible to quickly reconnect / reconfigure the connection through signaling through SCell (or small cell or small cell eNB) capable of data transmission. .

FIG. 9 is a diagram illustrating a configuration of a base station according to another embodiment.

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

The controller 1010 controls the overall operation of the base station according to the signaling and data transmission through the base station of the SCell when the RLF is generated in the base station of the PCell necessary for performing the above-described present invention.

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.

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

10, a 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.

Also, the controller 1120 controls the overall operation of the terminal according to the signaling and data transmission through the base station of the SCell when the RLF is generated in the base station of the PCell, which is necessary for performing the above-described present invention.

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 portions of the standard documents are added to or contained in 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)

In a method for a terminal to process an RLF,
Configuring a dual connection with a first base station and a second base station; And
Detecting when an RLF occurs in a cell associated with the first base station, and resuming signaling and data transmission through a cell associated with the second base station.

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