KR20180108391A - Methods for processing a radio link failure and Apparatuses thereof - Google Patents

Abstract

The present invention relates to a technology which repeatedly transmits control plane data or user plane data by carrier aggregation. More specifically, the present invention relates to a method for processing wireless link failure in case of repeatedly transmitting data by carrier aggregation based on a single base station, and a device thereof. According to one embodiment of the present invention, a method for a terminal to process a wireless link failure comprises the steps of: receiving an upper layer signaling containing information for data duplicated transmission through single base station carrier aggregation from a base station; based on the upper layer signaling, configuring a logic channel limited to one or more secondary cells, and a radio link control (RLC) entity for duplicated transmission; and if a wireless link failure occurs to the RLC entity, transmitting a secondary cell failure report to the base station without performing an RRC resetting procedure.

Description

[0001] METHOD FOR PROCESSING A RADIO LINK FAILURE AND APPARATUS [0002]

This disclosure relates to techniques for redundant transmission of control plane data or user plane data through carrier merging. And more particularly, to a method and an apparatus for processing a radio link failure in the case of redundant transmission of data with carrier merging based on a single base station.

As communications systems evolved, consumers, such as businesses and individuals, used a wide variety of wireless terminals.

In a mobile communication system such as LTE (Long Term Evolution), LTE-Advanced, and 5G of the current 3GPP series, a high-speed and large-capacity communication system capable of transmitting and receiving various data such as video data and wireless data is required beyond a voice- have.

To this end, technologies for next generation wireless access networks for accommodating data transmission and reception of more terminals and providing higher QoS are being developed after LTE-Advanced. For example, a development work for a tentative 5G network centering on 3GPP is under way.

Meanwhile, the base station can improve the data transmission / reception speed and capacity of the terminal by using a plurality of cells constituted (provided) by the base station. For example, a base station and a terminal can satisfy a requirement of a user by configuring a carrier merging using a plurality of carriers.

In particular, to reliably deliver services such as Ultra-Reliable and Low-Latency Communications (URLLC) with low latency, a more reliable and reliable method that does not suffer from data loss and speed is required. To do so, there is a need for a technique for ensuring reliability by redundantly transmitting data using a plurality of cells. In particular, it is necessary to minimize unnecessary operations for a failure processing procedure due to data processing or data processing failure even when data is redundantly transmitted.

However, at present, as described above, there is no specific operation and procedure for transmitting data redundantly using a plurality of cells, and for handling a radio link failure in a specific cell in a redundant transmission in case of occurrence.

The present embodiment is intended to provide a method and apparatus for constructing a carrier merge using a plurality of cells by a terminal and a base station, and transmitting and receiving data redundantly through a plurality of carriers-merged cells.

In addition, the present embodiment provides a concrete procedure for processing a radio link failure in a specific cell when a redundant data transmission is performed through merging of carriers.

According to an embodiment of the present invention, there is provided a method for processing a radio link failure by a UE, the method comprising: receiving an upper layer signaling including information for a data redundant transmission configuration through a single base station carrier merging from a base station; Configuring a RLC (Radio Link Control) entity for a logical channel and a redundant transmission, the RLC entity being limited to one or more secondary cells based on upper layer signaling; and if a radio link failure occurs in the RLC entity, And sending a cell failure report to the base station.

According to another aspect of the present invention, there is provided a method for a base station to control a radio link failure processing of a terminal, the method comprising: transmitting an upper layer signaling including information for a data redundancy transmission configuration through single base station carrier merging to a terminal; Receiving, from a mobile station, a secondary cell failure report transmitted without performing an RRC re-establishment procedure when a radio link failure occurs in a radio link control (RLC) entity configured for redundancy transmission based on a higher layer signaling A logical channel limited to one or more secondary cells and an RLC entity for redundant transmission.

According to another aspect of the present invention, there is provided a terminal for processing a radio link failure, comprising: a receiver for receiving an upper layer signaling including information for a data redundancy transmission configuration through a single base station carrier merging from a base station; A controller configured to configure an RLC (Radio Link Control) entity for a logical channel restricted to a secondary cell and a redundant transmission, and a transmitter for transmitting a secondary cell failure report to the base station without performing an RRC reset procedure when a radio link failure occurs in the RLC entity And a terminal device.

According to an embodiment of the present invention, there is provided a base station for controlling a radio link failure processing of a terminal,

A radio link failure occurs in a transmitter for transmitting upper layer signaling including information for redundant data transmission through a single base station carrier combination to a terminal and a Radio Link Control (RLC) entity for redundant transmission configured based on upper layer signaling A secondary cell failure report is transmitted from the UE to the secondary cell without performing the RRC re-establishment procedure, the UE configures an RLC entity for a redundant transmission and a logical channel restricted to one or more secondary cells based on upper layer signaling The base station apparatus comprising:

The above-described embodiment provides the effect that the terminal and the base station can transmit and receive the low-delay high-reliability data quickly and accurately.

In addition, this embodiment provides an effect of preventing waste of unnecessary failure processing resources even if wireless link failure occurs in a specific cell when data is transmitted / received through redundant transmission.

1 is a diagram showing an example of a layer 2 structure for a new radio access technology (New RAT).
2 is a diagram for explaining an RRC connection re-establishment procedure.
3 is a diagram illustrating an example of a structure for carrier merging-based data redundancy transmission.
4 is a diagram showing another example of a structure for carrier merging-based data redundancy transmission.
5 is a diagram showing another example of a structure for carrier merging-based data redundancy transmission.
6 is a diagram for explaining a terminal operation according to an embodiment.
7 is a view for explaining a base station operation according to an embodiment.
FIG. 8 is a diagram exemplifying information included in uplink AM (RLC) configuration information.
FIG. 9 is a diagram for explaining an unacknowledged mode (UM) RLC model according to an embodiment.
10 is a diagram for explaining a split bearer structure in dual connectivity between base stations using different radio access technologies.
11 is a diagram illustrating a terminal configuration according to an embodiment.
12 is a diagram illustrating a base station configuration according to an embodiment.

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 even though 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 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.

Enhanced Mobile Broadband (eMBB), massive Machine Type Communication (mMTC), and Ultra Reliable and Low Latency Communication (URLLC) have been proposed as typical usage scenarios in NR (New Radio), which is under discussion in 3GPP.

In this specification, a frequency, a frame, a subframe, a resource, a resource block, a region, a band, a subband, a control channel, a data channel, a synchronization signal, various reference signals, various signals, May be interpreted as past or presently used meanings or various meanings used in the future.

For example, LTE and NR in this specification refer to different radio access technologies, and a new radio access technology under discussion in Release-15 of 3GPP will be described as NR. NR may include various differences such as LTE, frame structure, channel, and core network technology, and various functions for wireless transmission, high-speed, and large-capacity data transmission in the high band can be added.

Hereinafter, for convenience of description, the conventional wireless access technology will be described as LTE and the new wireless access technology discussed in 3GPP will be described as NR. Also, the base station may be an eNB using LTE technology, a gNB using NR technology, and separately described according to need.

The term " cell " used herein refers to a wireless path for transmitting data, a wireless link, a carrier, and the like, and one base station can transmit and receive data through a plurality of cells. Alternatively, a terminal can transmit and receive data using a plurality of cells through cells controlled by two base stations. As described below, carrier merging is described when one base station controls a plurality of cells, and dual connectivity is described when a plurality of cells controlled by two or more base stations are used.

LTE  Dual Connectivity operation

Conventional LTE technology supports a dual connectivity technology in which a terminal simultaneously uses two base station radio resources. For multiple RX / TX terminals in the RRC Connected state, the dual connectivity operation is configured to connect to two base stations connected via a non-ideal backhaul and utilize the radio resources provided by two different schedulers located at each base station.

In the case of dual connectivity, a UE can transmit and receive data through a plurality of cells provided by two or more base stations, a main base station is described as a MeNB (master eNB), a base station for providing additional cells is called a SeNB (Secondary eNB) Will be described.

An SeNB addition procedure is used to set the terminal context to the SeNB in order to provide the terminal with radio resources from the SeNB.

NR (New Radio)

In 3GPP, research is underway on next generation / 5G wireless access technology (hereinafter referred to as NR for convenience of explanation). NR provides a new AS sublayer on top of the PDCP to provide flow-based QoS.

1 is a diagram showing an example of a layer 2 structure for a new radio access technology (New RAT).

As shown in FIG. 1, the main services and functions of the new AS sublayer are as follows.

- Mapping between a QoS flow and a data radio bearer;

- Marking QoS flow ID in both DL and UL packets.

In addition, a new user plane protocol layer can be applied to the connection to the next generation core. A single protocol entity of the new user plane protocol layer can be configured for each individual PDU session (the new user plane protocol layer is applicable to the NextGen Core. A single protocol entity of the new user plane protocol layer is configured for each individual PDU session.).

As a requirement for architecture and migration for next-generation wireless access technologies, the RAN architecture needs to support tight interworking between NR and LTE. LTE dual connectivity technology is expected to be recycled for tight interworking between NR and LTE. Also, dual connectivity techniques can be used between NR base stations in NRs. Dual connectivity in an NR environment can be defined as multi-connectivity. For example, the multi-connectivity may be defined as the mode of operation of a terminal for utilizing radio resources configured by an LTE base station and / or a NR base station (Multi-Connectivity: a multiple Rx / Tx UE in the E-UTRA and / or NR provided by multiple distinct schedulers connected via non-ideal backhaul.

On the other hand, NR can be constructed even at high frequencies (for example, a high frequency of 6 GHz or more). In this case, fast SINR drops may occur depending on the link blocking factor in the high frequency band and high transmission loss. This may lead to unnecessary delays or reduce reliability if the NR base station wishes to send control plane RRC messages or user plane data via the NR and the inter-terminal interface. In particular, this problem makes it difficult to provide services such as URLLC. In order to solve this problem, the control plane RRC message can be transmitted over one or more radio paths. Another example for solving this problem is to allow user plane data to be redundantly transmitted over one or more wireless paths.

Radio Link Failure (RLF)

A terminal in the RRC connection state can detect an RLF (Radio Link Failure) in the following cases.

- Detection of radio link failure from the physical layer

 1. If out-of-synchronization occurs for PCell / PSCell, start the related timer (upon receipt of N310 consecutive "out-of-sync" indications for the PCs from lower layers while neither T300, T301, T304 nor T311 is running: UE start < RTI ID = 0.0 > T310), < / RTI >

2. When triggering a measurement report during T310 operation (T312 is running running), the T312 started to receive N311 consecutive in-sync instructions from the lower layer When the T312 expires after failing to do so, the T312 will not be able to perform the requested re-establishment procedure, and upon expiration of the T310.

- When a random access problem occurs in the MAC layer (upon random access problem indication from MCG MAC while neither T300, T301, T304 nor T311 is running).

- When the maximum number of retransmissions is reached in the RLC layer. For example, when the maximum number of retransmissions is reached for the SRB or MCG DRB or the split DRB from the MCG RLC, the maximum number of retransmissions has been reached for an SRB or an MCG or a split DRB ).

The terminal considers the radio link failure for the MCG. When the terminal 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 directly moves 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.

In this way, when a radio link failure is detected, the conventional terminal performs an RRC connection reset procedure.

2 is a diagram for explaining an RRC connection re-establishment procedure.

Referring to FIG. 2, the terminal 201 and the PCell 202 configure an RRC connection (S210). The terminal 201 connected to the RRC may detect the occurrence of the radio link failure according to the various radio link failure conditions described above (S220).

Upon detecting the radio link failure and initiating the RRC connection re-establishment procedure, the UE 201 suspends all radio bearers except SRB0 (S230). Also, the terminal 201 releases SCell (s) if SCell (s) is configured (S240). Thereafter, the UE 201 performs a cell selection process to select an appropriate cell (S250), and transmits an RRC Connection Reestablishment Request message (S260). The terminal 201 receives the RRC Connection Reestablishment message (S270). The MS 201 receiving the RRC connection re-establishment message re-establishes the PDCP for the SRB 1 and re-establishes the RLC for the SRB 1. Also, the UE 201 performs a radio resource configuration procedure according to the received radio resource configuration dedicated information (radioResourceConfigDedicated), and resumes the SRB1 (S280). Through this process, when the RRC connection is reset, the terminal 201 transmits an RRC connection reset completion message (S290).

Single base station based redundant transmission

In order to increase the data transmission rate and transmission rate, a new radio access technology also needs to provide Carrier Aggregation (CA). For example, a terminal may transmit data through a plurality of cells based on a CA by a single base station. Hereinafter, the description will be made in terms of a cell, but a wireless path, a wireless link, a carrier, etc. may be used in combination if necessary. As used herein, the term " wireless path, " " wireless link, carrier, or cell " refers to a data path provided by a base station for data transmission / reception with a terminal.

In providing a CA by a single base station, a terminal may perform redundant transmission through one or more cells. For example, the control plane RRC message may be transmitted over one or more cells. As another example, the user plane data may be transmitted redundantly through one or more cells. However, the procedures and technical contents related to the redundant transmission using the carousel merging have not been disclosed. In particular, when performing a single base station based redundant transmission, a radio link failure may occur in a redundant transmission process through a plurality of cells, but there is no specific processing method therefor. Therefore, if a radio link failure occurs in any one of a plurality of cells according to the related art, an RRC reset procedure may be required. This may cause a problem that an inefficient processing procedure is performed in terms of redundant transmission of the same data.

In particular, redundant transmission over two or more radio paths can be considered as a method for reliably transmitting a service such as URLLC in a radio access network with low delay. However, when a CA is configured in a terminal based on a single base station, it has not been possible to support redundant transmission over two radio paths through a CA. In particular, when performing redundant transmission based on a single base station, a radio link failure may occur in a redundant transmission process through a plurality of cells, but there is no specific processing method. Accordingly, there has been a problem in that an inefficient RRC reset procedure has to be performed according to the prior art.

It is an object of the present disclosure to solve such a problem to provide a redundant transmission configuration method and apparatus capable of efficiently processing a service such as URLLC when carrier merging is performed on a single base station basis. And more particularly, to a method and apparatus for efficiently processing a radio link failure on a redundant transmission.

The present disclosure may be applied to any wireless access (e.g., LTE) network and terminals as well as next generation mobile communication (5G mobile communication / NR) terminals.

For convenience of explanation, the base station may represent an eNodeB or an LTE base station of an LTE / E-UTRAN or an NR Node, a CU, a DU, or a Node B in a 5G wireless network in which a CU (Central Unit) CU and DU can represent gNodeB, NR base stations implemented as a single logical entity. Hereinafter, the NR base station is referred to as the NR base station for convenience of explanation, but all the above-mentioned objects can be included in the scope of the present invention.

In NR-LTE, the following scenarios can be considered:

- When one or more NR cells and one or more LTE cells are provided through an LTE base station and apply a CA.

- one or more NR cells and one or more LTE cells are provided to the NR base station to apply the CA.

- one or more NR cells are provided to the NR base station to apply the CA.

- One or more LTE cells are provided to an LTE base station to apply a CA.

For convenience of description, the case where the NR base station applies CA through one or more NR cells will be described. This is for convenience of explanation, and other scenarios described above are also included in the scope of the present embodiment. In this case, the LTE base station and the NR base station provide at least one LTE cell and at least one NR cell, respectively, and apply dual connectivity to the terminal while applying the CA, as an embodiment of the present disclosure. For example, LTE-NR dual connectivity where the LTE base station becomes the master base station and the NR base station becomes the secondary base station, the NR-LTE dual connectivity where the NR base station becomes the master base station and the LTE base station becomes the secondary base station becomes the master base station A case where another NR base station provides a redundant transmission by applying a CA to a corresponding NR-NR dual connectivity as a secondary base station may also be included in the embodiment of the present disclosure. That is, in the case where a plurality of base stations or a plurality of NR base stations using different radio access technologies form dual connectivity, and a single base station also forms a carrier merging, the embodiment in this specification can be applied.

The NR base station can control NR radio resources of the UE. NR base station adds / modifies / releases / manages NR cell / cell group / transmission point / transmission point group / transmission / reception point / transmission / reception point group / TRP / antenna / antenna group / beam (hereinafter, NR radio resource allocation, NR radio resource allocation, NR radio bearer addition / correction / release, NR radio resource configuration, and NR mobility control. The NR base station may indicate one or more of the control functions described above for the terminal via an RRC configuration or reconfiguration message.

The NR base station can configure the CA through one or more NR cells in the UE.

The NR base station can perform data redundancy transmission to the CA using the PDCP redundancy transmission function.

The PDCP entity of the base station copies PDCP PDUs (or PDCP SDUs) having the same SN (sequence number) to duplicate or submit the PDCP PDUs (or PDCP SDUs) having the same SN to the lower layer to duplicate data through one or more wireless cells.

The PDCP entity of the UE receives PDCP PDUs (or PDCP SDUs) received via one or more radio cells. For example, the PDCP entity may first process the received data and discard the duplicated data. For another example, the function of detecting and discarding duplicated data can be performed by the PDCP entity. For example, the transmitting side may transmit data having the same PDCP SN through two paths, and the receiving side may detect (or detect) redundant data based on the PDCP SN. The base station can indicate to the terminal the configuration information for indicating / processing such an operation.

The PDCP entity of the UE copies / duplicates PDCP PDUs (or PDCP SDUs) having the same SN to the lower layer so as to transmit data redundantly through one or more wireless cells.

The PDCP entity of the base station receives PDCP PDUs (or PDCP SDUs) received via one or more radio cells. For example, the PDCP entity may first process the received data and discard the duplicated data. For another example, the function of detecting and discarding duplicated data can be performed by the PDCP entity. For example, the transmitting side may transmit data having the same PDCP SN through two paths, and the receiving side may detect (or detect) redundant data based on the PDCP SN. The base station can indicate to the terminal the configuration information for indicating / processing such an operation.

In the case of user plane data, redundant data transmission can be handled in the PDCP layer connected through the new AS sublayer. On the other hand, the RRC message may or may not pass through the new AS sublayer.

For example, in the case of an RRC message, the redundant data transmission in the PDCP can be handled through the new AS sublayer. In another example, in the case of an RRC message, a redundant data transfer can be handled by directly connecting to the PDCP without a new AS sublayer.

In order for a single base station to provide the UE with redundant transmission using the PDCP redundancy transmission function, the base station and the UE can be configured to transmit data redundantly through one or more NR cells provided through the CA.

3 is a diagram illustrating an example of a structure for carrier merging-based data redundancy transmission.

Referring to FIG. 3, the UE 301 and the BS 302 may perform a redundant transmission using one MAC entity. For example, the UE 301 may be configured to transmit data redundantly through one or more cells provided through a CA using one MAC entity. In order to perform data redundancy transmission through one MAC entity in the UE 301, the BS 302 may include one or more RLC entities and one or more logical channels associated with one MAC entity for one radio bearer Can be configured.

A MAC entity may include one or more cells. That is, the MAC entity may have one or more associated cells.

When the redundant transmission function is configured, each logical channel belonging to one radio bearer must be associated or mapped to one or more mutually exclusive cells. That is, redundant data must be transmitted in PDCP through different cells. At this time, the UE 301 configured to repeatedly transmit data through one or more cells provided by the single base station 302 using the CA may reach the maximum number of retransmissions in the RLC layer.

4 is a diagram showing another example of a structure for carrier merging-based data redundancy transmission. 5 is a diagram showing another example of a structure for carrier merging-based data redundancy transmission.

Referring to FIGS. 4 and 5, the terminals 401 and 501 may be configured to transmit data redundantly through one or more cells provided according to a CA using two MAC entities in the terminals 401 and 501.

In order to perform data redundancy transmission through two MAC entities in the UEs 401 and 501, the BS 402 and the MAC entity 502 for the redundant transmission are referred to as a second MAC entity , A conventional MAC entity based on a single base station is referred to as a first MAC entity, and a MAC entity added for redundant transmission based on a single base station is referred to as a second MAC entity). In this case, the base stations 402 and 502 may configure only one MAC entity or two MAC entities.

For example, when receiving an RRC (reconfiguration) message including configuration information indicating a single base station CA-based redundant transmission, the UEs 401 and 501 generate a second MAC entity.

Unlike the SCG MAC entity configured by the master base station and the independent base station (secondary base station) on the basis of the dual connectivity, the second MAC entity configured by a single base station can efficiently transmit detailed configuration information on two MAC entities Can be set.

For example, the first MAC entity and the second MAC entity may independently perform a MAC procedure. Since the second MAC entity is used for reliable redundancy transmission rather than efficiency, the second MAC entity may be performed independently of the first MAC entity for some or all of the MAC procedure. Such a MAC procedure may be one or more of BSR, SR, LCP, and PHR.

As another example, the first MAC entity and the second MAC entity may perform a MAC procedure through coordination. Although the second MAC entity is used for reliable redundancy transmission rather than efficiency, it may be efficient for some MAC procedures to coordinate themselves. Such a MAC procedure may be one or more of BSR, SR, LCP, and PHR.

As another example, the first MAC entity may provide a majority of procedures generated from two MAC entities, and the second MAC entity may perform only a limited function. For example, a function of associating data transmitted / received from a second RLC entity belonging to one radio bearer with a logical channel, a routing function related to the logical channel, or a function of adding / removing information for distinguishing the data on the data header can do.

In another example, the first MAC entity may trigger the BSR or the SR considering both the logical channel in the first MAC entity and the logical channel in the second MAC entity. The BSR transmitted by the first MAC entity to the BS may include a logical channel of the second MAC entity.

In another example, the second MAC entity may not trigger the BSR.

For example, the PDCP entity or the first RLC entity or the second RLC entity may send data available for transmission only to the first MAC entity.

Each MAC entity can identify a logical channel associated with each RLC entity belonging to one radio bearer. Each MAC entity may include one or more cells.

On the other hand, a UE configured to repeatedly transmit data through one or more cells provided through a CA by a single base station can reach the maximum number of retransmissions in the RLC layer. In this case, embodiments of specific operations of the terminal and the base station will be described with reference to the drawings. The base station and the terminal can process the procedure for the redundant transmission independently or in combination with the methods described below. Hereinafter, a case where one radio bearer supports redundant transmission through two RLC entities will be described as an example. This is for the sake of convenience of description, and the case of supporting redundant transmission through two or more RLC entities is also included in the scope of the present embodiment.

In the present specification, PCell and SCell are names for distinguishing each cell constituting a carrier merge. PCell is a cell for configuring / setting / resetting an RRC connection between a UE and a base station, and means a cell serving as a reference for handover. Also, SCell is a cell that is additionally provided for carrier merging and is different from PCell, and may be composed of one or more. Meanwhile, in the present disclosure, a terminal or a base station can configure a plurality of RLC entities as shown in FIGS. 3 to 5 to provide redundant transmission based on carrier merging. Hereinafter, a basic RLC entity associated with one radio bearer is described as a first RLC entity according to need, and an RLC entity additionally configured for redundant transmission is described as a second RLC entity. But is not limited to.

First Embodiment: RLC  On an entity RLC  When the maximum number of retransmissions is reached, the radio link failure detection

6 is a diagram for explaining a terminal operation according to an embodiment.

Referring to FIG. 6, the UE may perform step S610 of receiving upper layer signaling including information for a data redundancy transmission configuration through merging single base station carriers from a base station. For example, the UE can receive information for configuring the data redundancy transmission function through the single base station based carrier merging through the RRC message. In one example, the RRC message may include information for a logical channel restricted to one or more secondary cells and information for configuring an RLC entity (e.g., a second RLC entity) for redundant transmission.

The UE may perform a step of configuring a RLC (Radio Link Control) entity for a logical channel and a redundant transmission, which are restricted to one or more secondary cells based on upper layer signaling (S620). For example, the UE may configure an RLC entity for redundant transmission using a RRC message received from a base station, and configure a logical channel restricted to one or more secondary cells. A logical channel restricted to one or more secondary cells may be configured in association with an RLC entity configured for data redundancy transmission. In addition, a logical channel restricted to one or more secondary cells may be set to be limited to secondary cells other than the primary cell. That is, a logical channel limited to one or more secondary cells means a logical channel for transmitting data identical to data transmitted from a primary cell to one or more secondary cells through a secondary cell.

Through this, the UE can construct a logical channel and an RLC entity for redundant transmission and can duplicate the same data through carrier merging using a plurality of cells based on a single base station.

In step S630, if the RLC entity fails in a radio link failure, the UE transmits a secondary cell failure report to the base station without performing an RRC reset procedure. For example, a radio link failure may occur in the RLC entity in accordance with the above-described conditions of occurrence of the radio link failure. That is, the radio link failure can be detected when the number of data retransmissions of the RLC entity reaches the maximum number of retransmissions. In addition, for example, if the radio link monitoring (RLM) function is performed in the secondary cell, it can be detected when the above-described radio link failure condition is satisfied. The radio link monitoring function can be performed only in PCell (including PSCell in the presence of a secondary base station). PSCell means a cell that performs some of the functions of the primary cell among the secondary cells controlled by the secondary base station.

For example, if the UE detects a radio link failure in the RLC entity for the redundant transmission, the UE may transmit a secondary cell failure report to the BS. For example, if the number of retransmissions of the RLC entity for the redundant transmission reaches the maximum number of retransmissions, the RLC entity may report the RLC entity to the RRC layer and the RRC layer may transmit the secondary cell failure report to the base station through the RRC message. In this case, the RRC connection reset procedure described in FIG. 2 is not performed. That is, if a radio link failure is detected in the RLC entity configured for the redundant transmission, the UE can transmit the secondary cell failure report to the base station without performing the RRC reset procedure.

In another example, if a radio link failure is detected in the RLC entity associated with the primary cell (e.g., the first RLC entity), the terminal may reestablish the RRC connection according to the conventional RRC reset procedure.

In another example, the UE performs an RRC reset procedure when a radio link failure is detected in an RLC entity associated with a primary cell, and when a radio link failure is detected in an RLC entity configured for a redundant transmission, the UE does not perform an RRC reset procedure A secondary cell radio link failure report can be transmitted to the base station. That is, different radio link failure processing procedures may be configured according to the RLC entity.

The secondary cell radio link failure report can be transmitted to the base station via the primary cell.

Accordingly, even if a radio link failure occurs in the RLC entity used for the redundant transmission, resource waste and unnecessary delay due to the resetting of all the radio links can be prevented.

Hereinafter, the operation according to the present embodiment will be described in detail once again as a first RLC entity and a second RLC entity.

In one example, the first RLC entity may be an RLC entity associated with a logical channel configured to transmit data via a cell containing a PCell (or PSCell of a secondary base station). In this case, it is possible to detect a radio link failure when the number of RLC maximum retransmissions is reached for the first RLC entity. When the terminal 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 directly moves to the RRC IDLE state. Otherwise, if AS security is activated, RRC Connection Re-establishment procedure is executed.

As another example, the second RLC entity may be an RLC entity associated with a logical channel configured to transmit data through a cell that does not include a PCell (or PSCell of a secondary base station). That is, the second RLC entity refers to an RLC entity configured for redundant transmission and is associated with a logical channel restricted to one or more secondary cells. In this case, the radio link failure processing may be performed differently for the second RLC entity. For example, the second RLC entity may not detect a radio link failure even if the RLC maximum retransmission count is reached. As another example, it is possible to prevent the maximum number of retransmissions from reaching the second RLC entity. As another example, if the RLC maximum retransmission count for the second RLC entity is reached, the UE may suspend the corresponding second RLC entity or instruct the base station to fail the radio link. In this case, the radio link failure indication may be indicated through the first cell or the first cell group. Alternatively, the indication may be indicated via the first cell / cell group and / or the second cell / cell group. Herein, the first cell or the first cell group may include a cell or a specific cell group (a specific SCell indicated by a PCell and a base station) including a PCell in a single base station-based redundant transmission, a second cell or a second cell group may transmit a redundant transmission (Or a SCell cell or a SCell group not included in the first cell or the first cell group) that is not included in the first cell or the first cell group in the first cell. The base station can configure the terminal.

As another example, it is possible to detect a radio link failure when an RLC maximum retransmission count is reached for any one RLC entity. In this case, whether to perform the RRC connection re-establishment procedure may vary depending on the RLC entity in which the radio link failure is detected, as described above. That is, if a radio link failure is detected in the first RLC entity, the RRC connection reestablishment procedure is performed. If a radio link failure is detected in the second RLC entity, a radio link failure report can be transmitted to the base station without resetting the RRC connection.

7 is a view for explaining a base station operation according to an embodiment.

Referring to FIG. 7, the base station may perform a step of transmitting upper layer signaling including information for a data redundancy transmission configuration through single base station carrier merging to a mobile station (S710). For example, the base station may transmit information for configuring the data redundancy transmission function through the single base station-based carrier merging to the terminal through the RRC message. In one example, the RRC message may include information for a logical channel restricted to one or more secondary cells and information for configuring an RLC entity (e.g., a second RLC entity) for redundant transmission. The UE configures an RLC entity for a logical channel and a redundant transmission, which are limited to one or more secondary cells based on the received upper layer signaling. For example, the UE may configure an RLC entity for redundant transmission using a RRC message received from a base station, and configure a logical channel restricted to one or more secondary cells. A logical channel restricted to one or more secondary cells may be configured in association with an RLC entity configured for data redundancy transmission. In addition, a logical channel restricted to one or more secondary cells may be set to be limited to secondary cells other than the primary cell. That is, a logical channel limited to one or more secondary cells means a logical channel for transmitting data identical to data transmitted from a primary cell to one or more secondary cells through a secondary cell.

The base station can perform a step of receiving a secondary cell failure report transmitted from the terminal without performing an RRC reset procedure when a radio link failure occurs in an RLC (Radio Link Control) entity for redundant transmission configured based on upper layer signaling (S720). The base station can receive the same data repeatedly through a plurality of cells from the terminal. For example, the base station can receive data redundantly through the primary cell and the secondary cell. In this case, the UE transmits data to the Node B via two RLC entities.

As described above, each of the two RLC entities can detect a radio link failure according to the occurrence of the radio link failure condition described above. That is, the radio link failure can be detected when the number of data retransmissions of the RLC entity reaches the maximum number of retransmissions. In addition, it can be detected when the above-described radio link failure condition is satisfied.

For example, if the UE detects a radio link failure in the RLC entity for redundancy transmission of the UE, the BS may receive a secondary cell failure report from the UE. In this case, the base station does not perform the RRC connection reset procedure with the UE according to the failure of the radio link of the RLC entity. Alternatively, if a radio link failure is detected in the RLC entity of the UE associated with the primary cell, the base station may re-establish the RRC connection with the UE according to the conventional RRC reset procedure. Alternatively, if the radio link failure is detected in the RLC entity associated with the primary cell by mixing the above two cases, the base station performs the RRC re-establishment procedure with the UE and notifies the RLC entity configured for the redundant transmission of the UE A secondary cell radio link failure report can be received from the UE without an RRC reset procedure. That is, different radio link failure processing procedures may be performed according to the RLC entity.

The base station can receive the secondary cell failure report through the primary cell. Alternatively, the base station may receive a failure report via a secondary cell other than the secondary cell in which the radio link failure is detected.

Accordingly, even if a radio link failure occurs in the RLC entity used for the redundant transmission, the UE and the base station can prevent resource waste and unnecessary delay due to the resetting of all the radio links as in the conventional case.

Second Example : 1st RLC  Object and Second RLC  All objects RLC  When the maximum number of retransmissions is reached, the radio link failure detection

If two logical channels and two RLC entities are used for one bearer to provide redundant transmission through different cell / cell groups, even one RLC entity among the one or more RLC entities provided through that radio bearer If it works normally, you can send and receive data. Therefore, for a radio bearer providing redundant transmission, it is possible to detect a radio link failure only when the number of RLC maximum retransmissions is reached in all RLC entities provided through the corresponding radio bearer. That is, when redundant transmission is provided for a single radio bearer through a plurality of cells, it is possible to detect and process the radio link failure only when the RLC entity configured for a plurality of cells reaches the maximum number of RLC retransmissions.

For example, when the first RLC entity reaches the maximum RLC retransmission count, it may not detect the radio link failure. The UE may suspend or stop the transmission of the first RLC entity, or may instruct the base station to suspend transmission. For example, an instruction to the base station described above may be performed through the second cell or the second cell group. Or an instruction to the base station described above may be indicated through the first cell / cell group and / or the second cell / cell group. When the first RLC entity has reached the maximum RLC retransmission count (or in response to suspending / transmission of the first RLC entity or performing an indication operation to the base station), the second RLC entity determines the maximum retransmission number of RLC The radio link failure can be detected. 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.

As another example, the second RLC entity may be configured not to detect a radio link failure when the RLC maximum number of retransmissions is reached. The UE can suspend or stop the corresponding second RLC entity or instruct the BS to reach the maximum number of RLC retransmissions. For example, the terminal may indicate to the base station through the first cell or the first cell group. Alternatively, the terminal may indicate to the base station via the first cell / cell group and / or the second cell / cell group. When the second RLC entity has reached the maximum RLC retransmission count in the state where the second RLC entity has reached the maximum RLC retransmission count (or in response to suspending / transmission of the second RLC entity or performing an indication to the base station) The radio link failure can be detected. 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.

In this manner, when any one of the RLC entities reaches the RLC maximum retransmission count, the UE does not perform the RRC connection re-establishment operation, and all the RLC entities configured to perform the redundant transmission for one radio bearer The RRC connection resetting operation can be performed by detecting the radio link failure only when the RLC maximum retransmission number is reached.

Third Example : If you are providing redundant transmissions through a CA RLC  Set the maximum number of retransmissions to a specific value (for example, infinity).

FIG. 8 is a diagram exemplifying information included in uplink AM (RLC) configuration information.

Referring to FIG. 8, a base station can indicate the maximum number of retransmissions from 1 to 32 using uplink AM mode RLC configuration information for an AM mode RLC entity. The maxRetxThreshold information element of FIG. 8 is a parameter for RLC AM, t1 corresponds to retransmission one time, and t2 corresponds to two retransmissions. It is possible to instruct retransmission up to 32 times in the same form. The default value in the conventional LTE was 4 times.

In a case where one radio bearer supports redundancy transmission through two RLC entities, data transmission is possible when data transmission is possible in the other RLC entity even though a single RLC experiences radio link failure. The RLC entity may also experience a radio link failure in the physical layer before experiencing the maximum number of retransmissions. Accordingly, when one radio bearer supports redundant transmission through two RLC entities, the base station may set the maximum number of retransmissions to a specific value so that the RLC does not detect radio link failure.

For example, the base station can be configured by setting an infinite value to the maximum retransmission value. For another example, the RLC entity may be configured not to detect a radio link failure by not indicating a maximum retransmission value. For another example, the second RLC entity can be configured by setting an infinite value to the maximum retransmission value. In another example, the RLC entity may be configured not to detect a radio link failure by not indicating a maximum retransmission value only for the second RLC entity.

Fourth Example : RLC  Enable UM

FIG. 9 is a diagram for explaining an unacknowledged mode (UM) RLC model according to an embodiment.

Referring to FIG. 9, unlike Acknowledge mode, which performs retransmission in the RLC layer, RLC UM does not use retransmission. Therefore, the RLC entity may not experience a radio link failure due to retransmission. In order to prevent the RLC entity from experiencing a radio link failure due to retransmission, if the base station is configured to provide one PDCP bearer with PDCP redundancy transmission over two RLC entities, the base station may instruct the UE to use the RLC UM mode have.

For example, in a case where a single radio bearer is configured to perform a redundant transmission function through two RLC entities based on a single base station, the base station can instruct the RLC UM to configure each RLC entity. If the RLC entity configured for the redundant transmission is configured as an RLC UM, the RLC entity does not detect a radio link failure due to the RLC maximum retransmission count because it does not support retransmission.

As described above, when data of one radio bearer is redundantly transmitted through a plurality of RLC entities, the RRC connection re-establishment procedure according to the conventional radio link failure is not performed or selectively performed according to the characteristics of redundant transmission , Unnecessary procedures can be prevented from being performed.

On the other hand, when duplicating data, procedures and criteria on how to process the available data are also required. Therefore, a method of processing data available for transmission according to redundant transmission will be described below.

The buffer status reporting procedure may include data available for transmission (hereinafter referred to as "available data" or "transmittable data " for convenience of explanation) in the UL buffers of the UE associated with the MAC entity of the serving BS. Quot; amount ") to the serving base station.

In the conventional LTE, for the MAC buffer state reporting, the UE should consider the following as available data for transmission in the RLC layer.

- RLC SDUs, or segments (RLC SDUs, or segments thereof, that have not been included in an RLC data PDU)

- RLC data PDUs or portions (RLC data PDUs, or portions thereof, that are pending for retransmission (RLC AM).

In the conventional LTE, for the purpose of reporting the MAC buffer state, the UE should consider the PDCP control PDUs and the following as available data for transmission in the PDCP layer.

For any SDU that has not been submitted to the lower layer (PDUs for which PDU has been submitted to lower layers)

- the SDU itself, if not already processed by the PDCP (the SDU itself, if the SDU has not yet been processed by PDCP), or

If the SDU has been processed by the PDCP, the PDU (the PDU if the SDU has been processed by PDCP)

In addition, for a radio bearer mapped on the RLC AM, if the PDCP entity has performed a reset procedure, the UE shall consider the following as the amount of data available for transmission at the PDCP layer.

Except for those SDUs indicated to have been successfully delivered by the PDCP status report, to the SDU for that PDU that the PDU was submitting only to the lower layer prior to the PDCP reset, for the delivery of the corresponding PDUs not acknowledged by the lower layer Starting from the first SDU

- SDU, if not yet processed by the PDCP

- The PDU that was processed by the PDCP (the PDU has been processed by PDCP.

10 is a diagram for explaining a split bearer structure in dual connectivity between base stations using different radio access technologies.

Referring to FIG. 10, the NR base station 1001 is set as a master base station and the LTE base station 1002 is set as a secondary base station, so that dual connectivity can be configured. In this case, the master BS 1001 may comprise a radio bearer for transmitting and receiving data through the cells of the master BS, and a split bearer for transmitting and receiving data through the cells of the master BS 1001 and the secondary BS 1002. In the case of the split bearer, data is split and transmitted to the entity by the RLC _NR and the RLC _LTE in the PDCP _NR , and data is transmitted through the NR cell and the LTE cell, respectively.

The dual / multi-connectivity for NR (hereinafter referred to as dual connectivity for convenience of description, but providing two or more connectivity is also included in the scope of the present invention), the following three cases can be considered.

- LTE (Master Node) - NR (Secondary Node)

- NR (Master Node) - NR (Secondary Node)

- NR (Master Node) - LTE (Secondary Node)

The dual connectivity described below is applied to each of the above three cases [LTE (Master Node) - NR (Secondary Node), NR (Master Node) - NR (Secondary Node), NR (Master Node) - LTE . ≪ / RTI >

If the PDCP entity provides redundant transmission, the method described below may be used individually or in combination to process the available data in the terminal. This can be applied not only to a case where a single base station carries out a PDCP redundancy transmission through a plurality of cells based on a CA, but also when a PDCP redundancy transmission is performed through a plurality of cells based on two base stations. The structure of FIG. 3 to FIG. 5 may be used as an example of a case where a single base station performs a PDCP redundant transmission through a plurality of cells based on a CA. The structure of FIG. 10 can be used as an example of the case of performing the PDCP redundant transmission through a plurality of cells based on two base stations. FIG. 10 shows a case of NR (Master Node) - LTE (Secondary Node), and another example of performing PDCP redundancy transmission through a plurality of cells based on two base stations is an LTE (Master Node) A dual connectivity structure can be used. In this case, the New AS sublayer of the master node is not used.

1st Example : Redundant transmission On the bearer  With available data PDCP Amount of data  How to direct as many duplicates (multiple)

For one radio bearer providing redundant transmission, when instructing available data for transmission to the MAC entity for BSR triggering and buffer size calculation, the UE may operate as follows.

For example, if a condition (threshold / threshold) for a redundant transmission is configured and the redundant transmission condition is satisfied (or the redundant transmission condition parameter is greater than or equal to the redundant transmission threshold, (PDCP entity of the terminal) indicates twice the data buffered in the PDCP entity as available data for transmission to the MAC entity. It indicates n times the amount of data buffered in a PDCP entity that is redundantly transmitting over n radio channels through n logical channels.

For example, when the UE provides the PDCP redundancy transmission using two MAC entities in a single base station based on the CA as shown in FIG. 4 or 5, the UE (PDCP entity of the UE) The available data can indicate twice the amount of data buffered in the PDCP entity.

As another example, when a terminal provides a PDCP redundancy transmission using a single MAC entity in a single base station in a single base station as shown in FIG. 3, the terminal (PDCP entity of the terminal) Lt; RTI ID = 0.0 > buffered < / RTI >

For another example, for any SDU that has not been submitted to the lower layer by any PDU (For SDUs for which no PDU has been submitted to lower layers)

If the PDU has not yet been processed by the PDCP (the SDU itself, if the SDU has not yet been processed by the PDCP), the SDU itself.

If the SDU has been processed by the PDCP, the PDU (PDU if the SDU has been processed by PDCP).

It is possible to instruct the MAC entity to double the PDCP usable data calculated by the above method.

For another example, for any SDU that has not been submitted to the lower layer by any PDU (For SDUs for which no PDU has been submitted to lower layers)

- If the PDCP has not yet been processed by the PDCP, the PDCP-enabled data calculated by the SDU itself (if the SDU has not yet been processed by PDCP)

If the SDU has been processed by the PDCP, the PDU (PDU if the SDU has been processed by PDCP).

The PDCP usable data calculated by the above method can be indicated as a MAC entity. This is because the PDCP duplicate function may be a function provided by the PDCP. Therefore, when the PDCP PDU is duplicated / copied by the PDCP, the amount of the SDU data is doubled, since the PDCP PDUs already have twice the amount of data, but the PDU data amount can be directly designated as the terminal MAC entity.

For another example, for any SDU that has not been submitted to the lower layer by any PDU (For SDUs for which no PDU has been submitted to lower layers)

- If the PDCP has not yet been processed by the PDCP, the PDCP-enabled data calculated by the SDU itself (if the SDU has not yet been processed by PDCP)

- If the SDU is being processed by the PDCP and the PDCP has not been duplicated / copied yet, the PDCP usable data calculated by the SDU (or PDU)

- If the SDU has been processed by the PDCP, the PDU (if the SDU has been processed by the PDCP or PDCP and the SDU has been processed and duplicated / copied).

The PDCP usable data calculated by the above method can be indicated as a MAC entity. This is because the PDCP duplicate function may be a function provided by the PDCP. Therefore, when the PDCP PDU is duplicated / copied by the PDCP, since the PDCP PDUs are already twice the data amount calculated, the PDU data amount is doubled as much as the SDU data amount until the PDCP PDU is duplicated / copied. Terminal MAC entity.

Second Example : Redundant transmission On the bearer  With available data PDCP The amount of data  How to Direct

For one radio bearer providing redundant transmission, when instructing available data for transmission to the MAC entity for BSR triggering and buffer size calculation, the UE may operate as follows.

For example, if a condition (threshold / threshold) is configured for a redundant transmission and the redundant transmission condition is satisfied (or if the redundant transmission condition parameter is greater than or equal to the redundant transmission threshold, or if the physical layer has reached a redundant transmission condition , The UE (PDCP entity of the UE) indicates the data buffered in the PDCP entity as the available data for transmission to the MAC entity.

For example, as shown in FIG. 3, when a terminal provides a PDCP duplicated transmission using a single MAC entity based on a CA in a single base station, the terminal (PDCP entity of the terminal) transmits the PDCP entity Lt; RTI ID = 0.0 > buffered < / RTI >

As another example, if the UE provides the PDCP redundancy transmission using two MAC entities in a single base station based on the CA as shown in FIG. 4 or 5, the UE (PDCP entity of the UE) The amount of data buffered in the PDCP entity may be indicated by the available data.

As another example, if the UE provides a PDCP redundancy transmission using two MAC entities in a single base station based on a CA as shown in FIG. 4 or 5, the UE (PDCP entity of the UE) The amount of data buffered in the PDCP entity may be indicated by the available data. At this time, the terminal (PDCP entity of the terminal) does not indicate (or indicates 0) the amount of data buffered in the PDCP entity as available data for transmission to the second MAC entity.

For another example, for any SDU that has not been submitted to the lower layer by any PDU (For SDUs for which no PDU has been submitted to lower layers)

If the PDU has not yet been processed by the PDCP, the SDU itself (if the SDU has not yet been processed by PDCP).

If the SDU has been processed by the PDCP, the PDU (PDU if the SDU has been processed by PDCP).

The PDCP usable data calculated by the above method can be indicated as a MAC entity.

For another example, for any SDU that has not been submitted to the lower layer by any PDU (For SDUs for which no PDU has been submitted to lower layers)

If the PDU has not yet been processed by the PDCP, the SDU itself (if the SDU has not yet been processed by PDCP).

- If the SDU has been processed by the PDCP, then the PDU (the PDU if the SDU has been processed by PDCP)

The PDCP usable data calculated by the above method can be designated as each MAC entity.

Third Example : Duplicate transmission conditions Check  How to calculate the buffer size

It is possible to first check whether the redundant transmission condition is satisfied, and if the redundant transmission condition is not satisfied, the amount of PDCP usable data can be indicated to the MAC entity by the conventional method. The above-described first embodiment or second embodiment may be applied in the case of satisfying the redundant transmission condition.

The MAC entity of the UE indicates the MAC entity data to the serving BS through buffer status reporting (BSR) using the above-described embodiments.

As described above, the present embodiments provide the effect that the terminal can process the redundant transmission efficiently through two different radio paths when the CA is configured by a single base station.

Hereinafter, configurations of a terminal and a base station capable of performing a part or all of the above-described embodiments will be described with reference to the drawings.

11 is a diagram illustrating a terminal configuration according to an embodiment.

11, the UE 1100 includes a receiving unit 1130 that receives upper layer signaling including information for a data redundancy transmission configuration through merging of single base station carriers from a base station, and a receiving unit 1130 that receives one or more secondary cells A control unit 1110 configuring an RLC (Radio Link Control) entity for redundant transmission, and a secondary cell failure report to a base station without performing an RRC reset procedure when a radio link failure occurs in the RLC entity And a transmission unit 1120.

For example, the receiving unit 1130 may receive information for configuring the data redundancy transmission function through the single base station-based carrier merging through the RRC message. For example, the RRC message may include information on a logical channel restricted to one or more secondary cells and information for configuring an RLC entity for a redundant transmission.

The controller 1110 configures an RLC entity for redundant transmission using the RRC message received from the base station, and configures a logical channel limited to one or more secondary cells. A logical channel restricted to one or more secondary cells may be configured in association with an RLC entity configured for data redundancy transmission. In addition, a logical channel restricted to one or more secondary cells may be set to be limited to secondary cells other than the primary cell. That is, a logical channel limited to one or more secondary cells means a logical channel for transmitting data identical to data transmitted from a primary cell to one or more secondary cells through a secondary cell.

The transmitter 1120 can transmit data of a corresponding radio bearer over a plurality of RLC entities associated with one radio bearer. In addition, if the UE detects a radio link failure in the RLC entity for the redundant transmission, the transmitter 1120 can transmit a secondary cell failure report to the base station. For example, if the number of retransmissions of the RLC entity for the redundant transmission reaches the maximum number of retransmissions, the RLC entity may report the RLC entity to the RRC layer and the RRC layer may transmit the secondary cell failure report to the base station through the RRC message. In this case, the control unit 1110 does not perform the RRC connection re-establishment procedure. That is, if a radio link failure is detected in the RLC entity configured for the redundant transmission, the UE 1100 can transmit the secondary cell failure report to the base station without performing the RRC reset procedure. In another example, when a radio link failure is detected in an RLC entity associated with a primary cell (e.g., a first RLC entity), the control unit 1110 may reestablish the RRC connection according to a conventional RRC reset procedure. As another example, the controller 1110 performs an RRC reset procedure when a radio link failure is detected in an RLC entity associated with a primary cell, and when a radio link failure is detected in an RLC entity configured for a redundant transmission, And to transmit the secondary cell radio link failure report to the base station without a reset procedure. The transmitting unit 1120 may transmit the secondary cell radio link failure report to the base station through the primary cell.

The above-described radio link failure can be detected when the number of data retransmissions of the RLC entity reaches the maximum number of retransmissions. Or may be detected when any one of the above-described radio link failure conditions is satisfied.

In addition, the receiving unit 1130 receives downlink control information, data, and messages from the base station through the corresponding channel. Also, the controller 1110 controls the overall operation of the UE according to the failure of the radio link when the data is redundantly transmitted through the merge of carriers based on a single base station, which is necessary for performing the above-described embodiment. The transmitting unit 1120 transmits uplink control information, data, and a message to the base station through the corresponding channel.

12 is a diagram illustrating a base station configuration according to an embodiment.

Referring to FIG. 12, a BS 1200 includes a transmitter 1220 for transmitting upper layer signaling including information for a data redundancy transmission configuration through a single BS carrier merging to a UE, and a redundant transmission configured based on upper layer signaling And a receiving unit 1230 for receiving a secondary cell failure report transmitted from the UE without performing an RRC re-establishment procedure when a radio link failure occurs in an RLC entity. In this case, the UE may configure an RLC entity for a logical channel and a redundant transmission, which are limited to one or more secondary cells based on upper layer signaling.

The transmitter 1220 can transmit information for configuring the data redundancy transmission function to the UE through the RRC message through merging of carriers based on the single base station. For example, the RRC message may include information on a logical channel restricted to one or more secondary cells and information for configuring an RLC entity for a redundant transmission.

The UE configures an RLC entity for a logical channel and a redundant transmission, which are limited to one or more secondary cells based on the received upper layer signaling. For example, the UE may configure an RLC entity for redundant transmission using a RRC message received from a base station, and configure a logical channel restricted to one or more secondary cells. A logical channel restricted to one or more secondary cells may be configured in association with an RLC entity configured for data redundancy transmission. In addition, a logical channel restricted to one or more secondary cells may be set to be limited to secondary cells other than the primary cell.

The receiving unit 1230 can receive the same data redundantly through a plurality of cells from the terminal. For example, the receiving unit 1230 can receive data redundantly through the primary cell and the secondary cell. In this case, the UE transmits data to the Node B via two RLC entities.

As described above, each of the two RLC entities can detect a radio link failure according to the occurrence of the radio link failure condition described above. That is, the radio link failure can be detected when the number of data retransmissions of the RLC entity reaches the maximum number of retransmissions. Or may be detected when any one of the above-described radio link failure conditions is satisfied.

For example, if the UE detects a radio link failure in the RLC entity for redundant transmission of the UE, the receiving unit 1230 may receive the secondary cell failure report from the UE. In this case, the controller 1210 of the base station 1200 does not perform the RRC connection re-establishment procedure with the UE according to the failure of the radio link of the RLC entity. Alternatively, if a radio link failure is detected in the RLC entity of the UE associated with the primary cell, the control unit 1210 of the base station 1200 may re-establish the RRC connection with the UE according to the conventional RRC reset procedure. Alternatively, when the radio link failure is detected in the RLC entity associated with the primary cell by mixing the above two cases, the base station 1200 performs the RRC re-establishment procedure with the UE, and the RLC entity configured for the redundant transmission of the UE A secondary cell radio link failure report can be received from the terminal without an RRC reset procedure if a radio link failure is detected. That is, different radio link failure processing procedures may be performed according to the RLC entity.

The receiving unit 1230 can receive the secondary cell failure report through the primary cell. Alternatively, the receiving unit 1230 may receive a failure report through the secondary cell other than the secondary cell in which the radio link failure is detected.

In addition, the controller 1210 controls the overall BS to control the occurrence of the radio link failure in the UE in the case of redundant reception of data through merging of carriers based on a single base station, which is necessary to perform the above- .

The transmitting unit 1220 and the receiving unit 1230 are used to transmit and receive signals, messages, and data necessary for performing the above-described embodiments to and from the terminal.

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 (20)

A method for a terminal to process a radio link failure,
Receiving higher layer signaling including information for a data redundancy transmission configuration through merging a single base station carrier from a base station;
Constructing a RLC (Radio Link Control) entity for a logical channel and a redundant transmission, the RLC being limited to one or more secondary cells based on the higher layer signaling; And
And transmitting a secondary cell failure report to the base station without performing an RRC reset procedure when a radio link failure occurs in the RLC entity. The method according to claim 1,
The upper layer signaling includes:
A logical channel limited to the one or more secondary cells, and information for indicating the RLC entity for the redundant transmission. The method according to claim 1,
Wherein the logical channel limited to the one or more secondary cells comprises:
Wherein the data is a logical channel for transmitting data identical to data transmitted from a primary cell to the base station through the at least one secondary cell. The method according to claim 1,
Wherein the RLC entity for the redundant transmission comprises:
And is configured to be associated with the logical channel. The method according to claim 1,
The secondary cell failure report includes:
Wherein the RLC entity is triggered when the number of data retransmissions of the RLC entity reaches a maximum number of retransmissions. A method for a base station to control a radio link failure processing of a terminal,
Transmitting an upper layer signaling including information for a data redundant transmission configuration through a single base station carrier merging to a terminal; And
Receiving a secondary cell failure report transmitted from the UE without performing an RRC reset procedure when a radio link failure occurs in an RLC entity configured for redundancy transmission based on the higher layer signaling,
The UE configuring a logical channel restricted to the at least one secondary cell based on the higher layer signaling and the RLC entity for the redundant transmission. The method according to claim 6,
The upper layer signaling includes:
A logical channel limited to the one or more secondary cells, and information for indicating the RLC entity for the redundant transmission. The method according to claim 6,
Wherein the logical channel limited to the one or more secondary cells comprises:
Wherein the data is a logical channel for receiving data identical to data received in a primary cell from the terminal through the one or more secondary cells. The method according to claim 6,
Wherein the RLC entity for the redundant transmission comprises:
And is configured to be associated with the logical channel. The method according to claim 6,
The secondary cell failure report includes:
Wherein the RLC entity is triggered when the number of data retransmissions of the RLC entity reaches a maximum number of retransmissions. A terminal for processing a radio link failure,
A receiver for receiving an upper layer signaling including information for a data redundancy transmission configuration through merging a single base station carrier from a base station;
A controller configured to configure a logical channel (RLC) entity for RLC (Radio Link Control) for redundant transmission and a logical channel restricted to one or more secondary cells based on the upper layer signaling; And
And a transmitter for transmitting a secondary cell failure report to the base station without performing an RRC reset procedure when a radio link failure occurs in the RLC entity. 12. The method of claim 11,
The upper layer signaling includes:
A logical channel limited to the at least one secondary cell, and information for indicating the RLC entity for the redundant transmission. 12. The method of claim 11,
Wherein the logical channel limited to the one or more secondary cells comprises:
Wherein the data is a logical channel for transmitting the same data as the data transmitted from the primary cell to the base station through the at least one secondary cell. 12. The method of claim 11,
Wherein the RLC entity for the redundant transmission comprises:
And is connected to the logical channel. 12. The method of claim 11,
The secondary cell failure report includes:
Wherein the RLC entity is triggered when the number of data retransmissions of the RLC entity reaches a maximum number of retransmissions. A base station for controlling a radio link failure process of a terminal,
A transmitter for transmitting upper layer signaling including information for a data redundancy transmission configuration through a single base station carrier merging to a terminal; And
And a receiving unit for receiving a secondary cell failure report transmitted from the UE without performing an RRC reset procedure when a radio link failure occurs in a Radio Link Control (RLC) entity configured for redundancy transmission based on the higher layer signaling,
Wherein the UE configures a logical channel restricted to the at least one secondary cell based on the higher layer signaling and an RLC entity for the redundant transmission. 17. The method of claim 16,
The upper layer signaling includes:
A logical channel limited to the one or more secondary cells, and information for indicating the RLC entity for the redundant transmission. 17. The method of claim 16,
Wherein the logical channel limited to the one or more secondary cells comprises:
Wherein the base station is a logical channel for receiving data identical to data received in a primary cell from the terminal through the at least one secondary cell. 17. The method of claim 16,
Wherein the RLC entity for the redundant transmission comprises:
And is configured in association with the logical channel. 17. The method of claim 16,
The secondary cell failure report includes:
Wherein the RLC entity is triggered when the number of data retransmissions of the RLC entity reaches a maximum number of retransmissions.

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