KR20150034588A - Methods for transmitting the Buffer status report and Apparatuses thereof - Google Patents

Abstract

The present invention relates to a method and an apparatus for transmitting a buffer status report, wherein the buffer status report is used to provide information about the data available for transmission from uplink buffers of a terminal to a base station when the terminal forms dual connectivity with one or more base stations and transmits user data in a small-cell environment. More specifically, according to the present invention, a method for a terminal to transmit buffer status information includes: a step of forming dual connectivity with a first base station and a second base station for one or more logical channels or a logical channel group mapped onto a split bearer; and a step of transmitting the PDCP buffer status information of the logical channels or the logical channel group to the first base station or the second base station.

Description

FIELD OF THE INVENTION The present invention relates to a method for transmitting a buffer status report,

In the present invention, in a small cell environment, when a UE configures a dual connectivity with one or more base stations to transmit user data, the amount of data available for transmission from the uplink buffers of the UE to the base station the present invention relates to a method and apparatus for transmitting a buffer status report used to provide information on transmission of a buffer status report.

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) and LTE-Advanced of the current 3GPP series, there is a demand for a high-speed, large-capacity communication system capable of transmitting and receiving various data such as video and wireless data beyond a voice-oriented service.

For such a high-speed, large-capacity communication system, there is a need for a technique capable of increasing the capacity of a terminal by utilizing a small cell. Further, there is a need for a technique capable of increasing the capacity of a terminal by transmitting and receiving data by configuring a connection with a plurality of base stations including a small cell when the above-mentioned small cell is used.

In particular, when a terminal transmits a large amount of data at high speed using a plurality of base stations, the terminal needs to transmit to the base station the amount of accurate data to be transmitted in the uplink. In addition, a specific method of transmitting uplink data to be transmitted by a terminal to a plurality of base stations is also required.

According to the above-described needs, in the case where a terminal constituting a radio bearer with one or more base stations transmits buffer status information for uplink transmission, it is necessary to transmit the buffer status information transmitted to one or more base stations so as not to be duplicated or missing .

According to another aspect of the present invention, there is provided a method of transmitting buffer status information, the method comprising: configuring one or more logical channels or logical channel groups mapped to a split bearer to be duplexed with a first base station and a second base station And transmitting PDCP buffer status information of one or more logical channels or logical channel groups mapped to the split bearer to the first base station or the second base station.

The present invention also provides a method for receiving buffer state information from a first base station, the method comprising: establishing a dual connection to a second base station and a terminal for one or more logical channels or logical channel groups mapped to a split bearer; And receiving buffer status information.

According to another aspect of the present invention, there is provided a UE for transmitting buffer status information, comprising: a control unit configured to couple one or more logical channels or logical channel groups mapped to a split bearer to a first base station and a second base station; And a transmitter for transmitting the PDCP buffer state information of the logical channel or the logical channel group to the first base station or the second base station.

In addition, the present invention provides a first base station for receiving buffer status information, comprising: a controller configured to establish a dual connection to a second base station and a terminal for at least one logical channel or logical channel group mapped to a split bearer; And a receiver for receiving the information.

According to the present invention, when transmitting the buffer status information for uplink transmission, the terminal has an effect of transmitting the buffer status information transmitted to one or more base stations so as not to be duplicated or missing.

In addition, according to the present invention, in transmitting buffer status information of a logical channel or a logical channel group mapped to a split bearer configured as a dual connection, the available data amount information of the PDCP entity buffer is accurately transmitted to one or more base stations, It is effective to provide efficient use.

1 is a diagram showing an example of a MAC configuration diagram of a conventional terminal.
2 is a diagram showing an example of a bearer separation user plane structure.
3 is a diagram showing another example of the bearer separation user plane structure.
4 is a diagram illustrating an example of a network configuration to which the present invention can be applied.
5 is a diagram showing another example of a network configuration to which the present invention can be applied.
6 is a diagram showing another example of a network configuration to which the present invention can be applied.
Figure 7 is an illustration of the amount of available data of a logical channel mapped to a split bearer to illustrate the present invention.
8 is a diagram illustrating an example of a configuration of a MAC PDU according to an embodiment of the present invention.
9 is a diagram illustrating an example of an LCID value for UL-SCH according to another embodiment of the present invention.
10 is a diagram illustrating an example of a format of each PDCP BSR MAC control element.
11 is a flowchart illustrating an operation of a terminal according to another embodiment of the present invention.
12 is a flowchart illustrating an operation of a base station according to another embodiment of the present invention.
13 is a diagram illustrating a configuration of a user terminal according to another embodiment of the present invention.
14 is a diagram illustrating a configuration of a base station 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 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.

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, in the present specification, a base station or a cell has a comprehensive meaning indicating a part or function covered by BSC (Base Station Controller) in CDMA, Node-B 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, 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 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.

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.

In the Carrier Aggregation (CA) technology prior to 3GPP Release 11, a small cell can be constructed 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 described above, the macro cell and the RRH cell are configured to be scheduled under the control of one base station, and an ideal backhaul is required between the macro cell node and the RRH.

An ideal backhaul refers to a backhaul that exhibits very high throughput and very little delay, such as a dedicated point-to-point connection using optical fiber, LOS microwave (Line Of Sight microwave).

In contrast, a backhaul that exhibits relatively low throughput and large delay, such as Digital Subscriber Line (xDSL) and Non-LOS microwave, is called a non-ideal backhaul.

The plurality of serving cells may be merged through the single base station based CA technology described above to provide services to the terminal. That is, a plurality of serving cells may be configured for a terminal in a state of a radio resource control (RRC) connected state, and when an ideal backhaul is established between the macro cell node and the RRH, And RRH cells together constitute serving cells to provide services to the UE.

When a single base station based CA technology is configured, the terminal may have only one RRC connection with the network.

Access Stratum (hereinafter referred to as "NAS") mobility information (for example, TAI: information indicating the number of serving cells) in RRC connection establishment / re-establishment / Tracking Area Identity, and one serving cell provides a security input in RRC connection reset / handover. These cells are called PCell (Primary Cell). PCell can only be changed with the handover procedure. Depending on the capabilities of the terminals, SCells (Secondary Cells) can be configured as serving cells with PCells.

One base station that handles PCells and SCells has a different carrier (DL / UL PCC: Downlink / Uplink Secondary Component Carrier (DL / UL SCC: Downlink / Uplink Secondary Component Carrier) Only layers can be affected. For the higher layer (RLC / PDCP), the RLC / PDCP layer before the carrier merging technique is introduced is not affected. That is, the CA operation can not be distinguished in the RLC / PDCP layer.

1 is a diagram showing an example of a MAC configuration diagram of a conventional terminal.

Referring to FIG. 1, the MAC layer can perform various functions. For example, the MAC layer may perform mapping between logical channels and transport channels. In addition, the MAC layer can perform multiplexing of MAC SDUs (Service Data Units) with transport blocks (TBs) that are transferred from one or a plurality of different logical channels on transport channels of the physical layer . Also, the MAC layer may perform a function of de-multiplexing MAC SDUs (Service Data Units) from transport blocks (TBs) carried on physical layer transport channels from one or a plurality of different logical channels do. In addition, it may perform functions such as logical channel prioritization and error correction through hybrid automatic repeat request (HARQ). The MAC layer also provides data transmission services for logical channels. Each logical channel type can be defined according to what type of information is transmitted. One radio bearer in one MAC layer entity is mapped to one logical channel. Hereinafter, a merging technique between base stations connected by non-ideal backhaul will be described by way of example with reference to the drawings.

Figs. 2 and 3 are diagrams showing examples of bearer separation user plane structures.

Referring to FIGs. 2 and 3, even when there is a non-ideal backhaul between base stations, radio resources of a plurality of base stations can be merged and used for bearer transmission. For efficient radio resource scheduling in a non-ideal backhaul environment, each base station needs to have an independent scheduler. For example, when using a first base station (macro cell base station or master base station or MeNB) and a second base station (small cell base station or secondary base station or SeNB) for one radio bearer transmission, An RLC entity and a MAC entity may be configured in each of the first base station and the second base station.

For example, referring to FIG. 2, a first BS has one PDCP entity, a RLC entity, and a MAC entity for a specific radio bearer in a bearer separation structure in which one radio bearer is separated into a second base station. And the second base station can have the RLC entity and the MAC entity for the corresponding radio bearer. Hereinafter, the RB entity and the RB provided through the MAC entity to the first base station and the second base station, respectively, as the right radio bearer of FIG. 2, will be referred to as a separate bearer.

As another example, referring to FIG. 3, the bearer may be separated from the RLC entity by the first base station. Also in this case, the first base station can have one PDCP entity, RLC entity and MAC entity for a specific radio bearer. And the second BS for the corresponding radio bearer may have a MAC entity separately from the first BS in a bearer configured by bearer separation. As another example, an RLC entity may be further provided.

The buffer status report procedure is a procedure used to provide information to the serving cell base station about the amount of available data for transmission in the terminal uplink (UL) buffers. This specific buffer status reporting procedure is described in 3GPP TS 36.321 5.4.4. The Buffer Status Report (BSR) should be triggered when the following events occur:

Uplink data is available for one logical channel belonging to one logical channel group (LCG) for transmission in a Radio Link Control (RLC) entity or a Packet Data Convergence Protocol (PDCP) entity, Loses. And the data belongs to one logical channel belonging to any logical channel group and having a higher priority than the priority of logical channels for already available data, or belongs to one logical channel belonging to one logical channel group No data is available for any. In this case, the buffer status report is called " Regular BSR ".

- The buffer status report is called "Padding BSR" when an uplink resource is allocated and the number of padding bits is equal to or greater than the size of the buffer status report MAC control element plus its subheader.

The buffer status report when the retransmission buffer status report timer (retxBSR-Timer) has expired and the UE has available data for transmission on any of the logical channels belonging to the logical channel group is also referred to as " Regular BSR ".

- The buffer status report when the periodic buffer status report timer (periodicBSR-Timer) expires is called "Periodic BSR".

One MAC Protocol Data Unit (PDU) may include at most one MAC buffer status report control element (BSR control element).

The UE must transmit at most one Regular / Periodic BSR within one Transmission Time Interval (TTI). If the UE is requested to transmit a plurality of MAC PDUs in one TTI, the UE may include a padding BSR in any of the MAC PDUs that do not include a Regular / Periodic BSR.

All BSRs transmitted in one TTI always indicate the buffer status after all MAC PDUs have been created for this TTI. Each logical channel group should report at most one buffer status value per TTI. And this value should be reported in all buffer status reports (BSRs) that report buffer status for this logical channel group.

The above-described data available for transmission will be described in more detail.

For reporting the buffer status of the MAC layer, the UE shall consider the following as the amount of data available in the RLC layer:

Consider RLC SDUs, or segments, that are not yet included in the RLC data PDU.

Consider RLC data PDUs (RLC AM) pending for retransmission.

For reporting the buffer status of the MAC layer, the UE must consider the following PDCP control PDUs as the amount of data available in the PDCP layer.

If there is an SDU that has not yet been processed by the PDCP for an SDU for which a PDU has not been submitted as a lower layer, consider the SDU itself. In addition, if there is an SDU processed by the PDCP for an SDU to which a PDU is not submitted as a lower layer, the PDU is considered.

PDUs from the first SDU for delivery of the corresponding PDUs not acknowledged by the lower layer, except for those SDUs that have been successfully delivered by the PDCP status report, to the lower layer prior to PDCP reset, If there is an SDU that has not yet been processed by the PDCP for the SDU, consider the SDU itself. In addition, if there is an SDU processed by the PDCP, the PDU is considered.

A particular bearer, such as the right bearer (split bearer) shown in FIG. 2 or FIG. 3, terminates the S1-U interface at the first base station for one bearer and uses a bearer split user plane structure Through the first base station and the second base station. The bearer separated bearer may also have a scheduler at a plurality of base stations for one bearer transmission.

As described above, the amount of available data to be provided through the existing buffer status reporting for the uplink transmission is calculated by summing the available data amount of the RLC layer and the PDCP layer.

Therefore, when a single bearer is configured to be processed through the first base station and the second base station by using a user plane structure that is bearer-split from the first base station like the specific bearer separated in FIG. 2 or 3 , A problem may occur at the time of reporting the buffer status. For example, the amount of available data in the PDCP layer may be calculated in duplicate when calculating the uplink buffer through the first base station and in calculating the uplink buffer through the second base station. Thus, excessive scheduling may occur relative to the total uplink buffer amount of the UE when performing uplink scheduling at the first base station or uplink scheduling at the second base station. That is, information on the amount of available data included in one PDCP entity is included in a plurality of buffer status reports in a superimposed manner, so that information on the actual available data amount can not be correctly transmitted to the base station.

In summary, even if different base stations are connected by a non-ideal backhaul, as described above, data can be transmitted by merging radio resources through a plurality of base stations. In addition, separate schedulers were required for individual base stations for one bearer transmission.

In this case, when a specific bearer is configured to be processed through the first base station and the second base station using a user plane structure that is bearer-split at the first base station, when calculating the uplink buffer through the first base station There may occur a problem that the amount of available data of the PDCP layer is overlapped when the uplink buffer is calculated through the second base station. Therefore, scheduling that exceeds the total uplink buffer amount of the UE may cause a problem of wasting radio resources.

In order to solve the above problems, the present invention provides a method of accurately reporting a buffer state even when the different BSs are configured to transmit data by merging radio resources through a separate scheduler for a specific bearer separated from the bearer to provide. For example, it is possible to provide a method by which a terminal can efficiently use radio resources by allowing an amount of available data corresponding to the total uplink buffer amount for logical channels of a corresponding radio bearer to be reported to individual base stations The purpose.

4 to 6 are diagrams showing respective embodiments of a network configuration scenario to which the present invention can be applied.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In this specification, a terminal establishes an RRC connection with a terminal in establishing dual connectivity according to the network configuration scenario of the present invention, And describes a base station serving as a mobility anchor for the core network as a master base station or a first base station. The master base station or the first base station may be a base station that provides macrocells according to a scenario described below, and may be a base station that provides any small cell in a dual connection situation between small cells.

Meanwhile, a secondary base station or a second base station, which is distinguished from the master base station in the double connection environment and provides additional radio resources to the terminal, is described as a secondary base station or a second base station.

The first base station (master base station) and the second base station (secondary base station) may each provide at least one cell to the terminal, and the first base station and the second base station may be connected through the interface between the first base station and the second base station. have.

In addition, for ease of understanding, a cell associated with a first base station may be referred to as a macro cell, and a cell associated with a second base station may be referred to as a small cell. However, in the small cell cluster scenario described below, the cell associated with the first base station can also be described as a small cell, and in the double connection situation between the macro cells, the cell associated with the second base station can also be described as a macro cell.

The macrocell in the present invention may mean at least one or more cells, and may be referred to as collectively referring to all the cells associated with the first base station. Also, a small cell may mean at least one or more cells, and may be referred to as collectively referring to the entire cell associated with the second base station. However, in a specific scenario, such as a small cell cluster as described above, it may be a cell associated with the first base station, in which case the cell of the second base station may be described as another small cell or another small cell.

In addition, the terminal may perform communication through a plurality of cells associated with the first base station and a plurality of cells associated with the second base station, and in this case, among the plurality of cells associated with the first base station, The specific cell can be described as the first base station PCell. Also, a specific cell among a plurality of cells associated with the second base station can be described as the second base station PCell. And the second base station PCell refers to a cell that performs all or a part of the functions of the above-described PCell among the cells associated with the second base station. For example, the second base station PCell may perform a PUCCH transmission / reception function. When a dual connection is established in a terminal, a cell associated with the first base station or a serving cell associated with the first base station is referred to as a master cell group, and a cell associated with the second base station or a serving cell associated with the second base station is referred to as a secondary cell group can do. A cell group is used as a concept to distinguish a base station from a terminal.

4 is a diagram illustrating an example of a network configuration to which the present invention can be applied.

4, the macrocell 402 and the small cells 401 have the same carrier frequency F1 and the first base station 410 and the second base station 432, 434 and 436 have non-ideal backhaul non-ideal backhaul. Small cells may be overlaid within macro cell coverage. An outdoor small cell environment and a small cell cluster are considered.

5 is a diagram showing another example of a network configuration to which the present invention can be applied.

5, the macro cell 502 and the small cell 501 have different carrier frequencies F1 and F2 and the first base station 510 and the second base station 532, 534, and 536 have different carrier frequencies, The nodes are connected through a non-ideal backhaul. Small cells may be overlaid within macro cell coverage. An outdoor small cell environment or an indoor small cell environment and a small cell cluster are considered.

6 is a diagram showing another example of a network configuration to which the present invention can be applied.

6, there are only small cells with only one or more carrier frequencies (F1 or F2), and between second base stations 610, 612 and 614 providing a small cell are non- backhaul. Indoor small cell environments and small cell clusters are considered.

That is, as shown in FIG. 4 and FIG. 5, the terminal can be connected to a macro cell and a small cell to perform communication. Also, as shown in FIG. 6, the terminal may be connected to a plurality of small cells to perform communication.

In the scenarios of FIGS. 4-6, the second base station may each operate as a stand-alone base station. That is, for transmission of control plane data, the UE can establish one RRC connection with the second base station and set one or more Signaling Radio Bearers (SRBs). For user plane data transmission, the terminal may have one or more DRBs (Data Radio Bearers) with the second base station.

In the scenarios of FIGS. 4-6, a terminal may transmit user plane data via one or more second base stations (or in cooperation between a first base station and one or more second base stations) under the control of a first base station . Alternatively, user plane data may be transmitted through cooperation between the second base station (small cell base station).

That is, for transmission of control plane data, the UE establishes one RRC connection with the first base station of FIG. 4 or FIG. 5 or the first base station (small cell base station) of FIG. 6, The SRBs (Signaling Radio Bearers) may be configured to be transmitted through the first base station or the first base station and the second base station. In order to transmit user plane data, the UE may configure one or more DRBs (Data Radio Bearers) through the first base station of FIG. 4 or FIG. 5 or the first base station of FIG. 6 (small cell base station). Or the UE may configure one or more DRBs through the first and second base stations for user plane data transmission.

Figure 7 is an illustration of the amount of available data of a logical channel mapped to a split bearer to illustrate the present invention.

As shown in FIG. 7, the UE has an RLC entity RLC-M that is peered to the RLC entity of the master base station with respect to the split bearer and an RLC entity RLC-S that is peered to the RLC entity of the secondary base station. In addition, the terminal has an intra-terminal MAC entity (MAC-M) peered to the MAC entity of the master base station and an intra-terminal MAC entity (MAC-S) peered to the MAC entity of the secondary base station.

 Referring to FIG. 7, according to the existing available data amount calculation method, since the MAC layer of the UE, the MAC entity of the UE, or the logical channel mapped to the MAC entity of the UE calculates the sum of available data of the upper layer, You can request too much. For example, the terminal may send a buffer status report to each base station. In this case, the intra-terminal MAC entity (MAC-M: MAC-Master) peered to the MAC entity of the master base station transmits the amount of available data 500 of the PDCP entity to the buffer status report transmitted to the first base station, The amount of available data of the peered RLC entity (RLC-M: RLC-Master) 200 may include 700 available data amount information summed. In the same way, an intra-terminal MAC entity (MAC-Secondary) peered to a MAC entity of a secondary base station transmits an amount of available data 500 of a PDCP entity and an RLC (RLC-S: The amount of available data of 100 in the RLC-Secondary layer may be included. Therefore, there is a problem that 500 usable data amount is excessively transmitted as compared with 800 (500 + 200 + 100), which is the total available data amount included in each layer of the UE.

In order to solve such problems, the present invention provides an efficient buffer status reporting method based on each of the following embodiments. Hereinafter, for convenience of explanation, a logical channel mapped to a split bearer is mainly described, and the same method can be applied to a logical channel group as well as a logical channel. Also, the PDCP buffer status information means the amount of available data of the PDCP layer.

1st Example : detach On the bearer Mapped  Logical channel PDCP  A method for transmitting buffer status information separately from a buffer status report.

FIG. 8 is a diagram illustrating an example of a configuration of a MAC PDU (Protocol Data Unit) according to an embodiment of the present invention.

Referring to FIG. 8, the MAC PDU includes one MAC header, 0 or more MAC SDUs (Service Data Units), 0 or more MAC control elements, and optionally includes padding do.

The MAC PDU header is composed of one or more MAC PDU subheaders 801. Each subheader 801 corresponds to one MAC SDU, one MAC control element, or padding (MAC PDU header consists of one or more MAC PDU subheaders, each corresponding to a subheader corresponding to a MAC SDU, a MAC control element or padding).

The LCID (Logical Channel ID) field included in the MAC header identifies the logical channel instance of the corresponding MAC SDU or the corresponding MAC control element or type of padding.

The UE according to the first embodiment of the present invention can transmit PDCP buffer status information for a logical channel or a logical channel group mapped to a split bearer to the BS in a manner different from the buffer status report.

For example, in the case of a separate bearer configured by separating one or more bearers such as the specific bearer shown in FIG. 2 or FIG. 3, a PDCP for a logical channel (or a logical channel group including logical channels) Buffer status information including buffer size information can be separately transmitted to the base station. For example, the PDCP buffer status information may be transmitted via a MAC Control Element. For this purpose, a separate Logical Channel ID (LCID) value may be defined. Separate LCID values may be defined as illustrated by way of example in FIG.

9 is a diagram illustrating an example of an LCID value for UL-SCH according to another embodiment of the present invention.

As shown in FIG. 9, the UE can transmit PDCP buffer status information to the first BS and / or the second BS. Therefore, the PDCP buffer status information is duplicated and not separately included in the buffer status report, so that information on the amount of available available data can be transmitted.

In one example, the PDCP buffer state information may be included in the MAC control element and transmitted to the first base station and / or the second base station. Specifically, the format of the PDCP buffer state information MAC control elements may be divided into a PDCP Short BSR format, a PDCP Truncated BSR, and a PDCP Long BSR format. That is, the PDCP buffer status report can be transmitted using the BSR format, and can be distinguished from the existing BSR using a specific index.

10 is a diagram illustrating an example of a format of each PDCP BSR MAC control element.

Referring to FIG. 10, the UE can transmit PDCP buffer status information to the first base station and / or the second base station. In this case, the UE can transmit the PDCP buffer status information using the BSR format. In order to distinguish the BSR from the existing BSR, the BSR including only the PDCP buffer state information may be divided into separate indexes as shown in FIG.

Specifically, for example, the PDCP Short BSR / PDCP Truncated BSR format 1000 includes one logical channel group ID (LCG ID) field and one corresponding buffer size field as shown in FIG. The logical channel group ID field is a field for identifying a logical channel group to which buffer status information is to be reported, and may be composed of 2 bits in length.

10, the PDCP Long BSR format may include four buffer size fields 1010, 1020 and 1030 corresponding to the LCG IDs # 0 to # 3. In FIG. 10, the buffer size is composed of six bits. However, the PDCP BSR may be designed to have a value smaller than six bits by applying different levels to the existing BSR. For example, it may be designed with three bits that can have eight indices, four bits that can have sixteen indices, five bits that can have 32 indices, and so on.

In one example, the buffer size field of FIG. 10 includes the total amount of data available in the PDCP layer for the logical channel (or logical channel group comprising bearer separation logical channels) that is mapped to the split bearer through the first and second base stations Lt; / RTI >

In this case, the base station receiving the PDCP buffer status information can estimate the available data amount of the PDCP layer that can be processed through each base station. For example, the BS multiplies the RLC layer (or entity) that is peered to the first base station and the RLC layer (or entity) that is peered to the second base station in the PDCP layer (or entity) Lt; RTI ID = 0.0 > PDCP < / RTI > That is, the total amount of available data of the PDCP layer is divided according to the distribution ratio, and the buffer status information of the PDCP layer to be processed by each base station can be confirmed. Each of the first BS and the second BS transmits the PDCP buffer status to be processed in each of the BSs in the existing buffer status report (short BSR, truncated BSR, or long BSR) calculated by summing up the available data amount of the RLC layer and the PDCP layer The amount of available data of the RLC layer of each base station can be confirmed by subtracting the value of the information. Therefore, each base station can calculate the amount of available data to be transmitted through each base station by summing the available data amount of the distributed PDCP layer according to the amount of available data and the distribution ratio of the RLC layer for each base station. Each base station can calculate an actual uplink radio resource (uplink grant) to be scheduled through each base station in the above-described manner and allocate uplink radio resources to be provided through each base station.

The distribution ratio of the RLC layer (or entity) peered to the first base station to the RLC layer (or entity) peered to the second base station in the intra-UE PDCP layer (or entity) Lt; / RTI > For example, when the first base station establishes a dual connection for the split bearer to the terminal through signaling with the second base station. Or dynamically changed according to radio quality and may be exchanged periodically or according to a specific event through signaling through the interface between the first and second base stations. When calculating the distribution ratio dynamically, one or more of the calculation period for calculating the distribution ratio, the change period for changing the distribution ratio, and the trigger condition for interface signaling may be exchanged together. When the distribution ratio of the RLC layer (or entity) peered to the first base station to the RLC layer (or entity) peered to the second base station in the PDCP layer (or entity) in the terminal is dynamically changed, 2 base station can provide this information to the terminal through RRC signaling or MAC signaling.

In another example, the buffer size field of FIG. 10 computes the total amount of data available at the PDCP layer for the logical channel of the split bearer (or logical channel group comprising bearer separation logical channels) through the first and second base stations The rate information may be included.

In this case, the BS receiving the PDCP buffer status information transmits the total amount of available data of the PDCP layer in the existing BSR (short BSR or Truncated BSR or Long BSR) calculated by summing the available data amount of the RLC layer and the PDCP layer The total amount of usable data of the PDCP layer can be calculated. Then, the BS subtracts the available data amount of the PDCP layer from the existing BSR (short BSR or Truncated BSR or Long BSR) calculated by summing the available data amount of the RLC layer and the PDCP layer, Able to know. Therefore, the actual uplink radio resource (uplink grant) to be scheduled through each base station can be calculated by summing the amount of available data of the RLC layer and the amount of available data of the PDCP layer to be processed through each base station. Each base station that has calculated the uplink radio resource can allocate uplink radio resources to be provided through each base station. The distribution ratio of the RLC layer (or entity) peered to the first base station to the RLC layer (or entity) peered to the second base station in the intra-UE PDCP layer (or entity) Lt; / RTI > For example, when the first base station establishes a dual connection for the split bearer to the terminal through signaling with the second base station. Or dynamically changed according to radio quality and may be exchanged periodically or according to a specific event through signaling through the interface between the first and second base stations. When calculating the distribution ratio dynamically, one or more of the calculation period for calculating the distribution ratio, the change period for changing the distribution ratio, and the trigger condition for interface signaling may be exchanged together. When the distribution ratio of the RLC layer (or entity) peered to the first base station to the RLC layer (or entity) peered to the second base station in the PDCP layer (or entity) in the terminal is dynamically changed, 2 base station can provide this information to the terminal through RRC signaling or MAC signaling.

In this manner, in the first embodiment, the UE can transmit the PDCP buffer status information related to the available data amount of the PDCP layer separately from the existing BSR.

Second Example : A method in which a terminal calculates available data for each base station according to a distribution ratio and transmits the calculated data.

When one or more bearers are configured as split bearers as in the specific bearer shown in FIG. 2 or FIG. 3, the amount of available data for the logical channel (or logical channel group) mapped to the split bearer described above is divided for each base station It can be reported via existing BSR (short BSR or Truncated BSR or Long BSR) MAC CE.

To this end, the UE uses a bearer-split user plane structure to allocate a logical channel (or logical channel group) mapped to a split bearer configured to process data via the first and second base stations in the PDCP layer When calculating the amount of usable data, it is possible to calculate the amount of usable data of the existing PDCP layer together with the distribution ratio to individual base stations.

In one example, a terminal may use a bearer split user plane structure to provide a logical channel (or logic) that is mapped to a split bearer configured to process data through the first and second base stations (or via one or more base stations) Channel group) can calculate the buffer status information (amount of available data) of each PDCP layer for each base station (or cell group) in proportion to the uplink grant information in the corresponding TTI received for each base station. Alternatively, the UE may calculate the buffer status information (amount of available data) of each PDCP layer for each base station (or cell group) based on the uplink grant averaging for the previous or recent TTI multiple periods. That is, the amount of available data in the PDCP layer for the corresponding logical channel is multiplied by the ratio of the uplink grant (or the uplink grant average value in the previous (latest) TTI multiple) to the corresponding TTI received for each base station, It is possible to calculate the buffer status information of the individual (or cell group) PDCP layer. For example, if the first base station uplink grant is a and the second base station uplink grant is b, the uplink grant ratio a / (a + b) is multiplied by the total amount of available data of the PDCP layer, The buffer status information of the PDCP layer can be calculated. Alternatively, a method of calculating the buffer status information of each PDCP layer for each base station (or each cell group) may be performed by using downlink allocation instead of uplink grant or by summing downlink allocation with uplink grant have. To this end, in the RRC message, logical channel configuration information included in radio resource configuration dedicated information or radio resource configuration dedicated information, or MAC-MainConfig configuration information included in radio resource configuration dedicated information, TTI period information for calculating the amount of available data of the layer and / or information for displaying it. Alternatively, the aforementioned information for calculating the amount of available data of the PDCP layer to the terminal may be preset.

In another example, a terminal may use a bearer split user plane structure to provide a logical channel (or logic) that is mapped to a split bearer configured to process data through the first and second base stations (or via one or more base stations) (Amount of usable data) for each BS of the PDCP layer in proportion to the uplink grant for periodic BSR-Timer included in the MAC-MainConfig information element for each base station have. Alternatively, the UE can calculate the buffer status information (amount of available data) for each base station (or cell group) of the PDCP layer in proportion to the uplink grant during retxBSR-Timer included in the MAC-MainConfig information element. Alternatively, the UE receives new information (for example, a calculation cycle) necessary for calculating the ratio on the RRC message, and calculates a ratio of the uplink grant according to each base station (or cell group) of the PDCP layer, The buffer status information (the amount of available data) can be calculated. That is, the available data amount of the PDCP layer for the corresponding logical channel is multiplied by the uplink grant ratio during the periodic BSR-Timer or the retxBSR-Timer for each base station, and the PDCP layer is available for each base station (or per cell group) The amount of data can be calculated. Specifically, for example, if the first base station uplink grant is a and the second base station uplink grant is b for the above-mentioned period, the ratio of a / (a + b) The amount of available data of the PDCP layer of the first base station can be calculated by multiplying the amount of data. Alternatively, the downlink allocation may be used in place of the uplink grant mentioned above, or the uplink grant and the downlink allocation may be summed and used. To this end, in the RRC message, the logical channel configuration information included in the radio resource configuration dedicated information or the radio resource configuration dedicated information, or the MAC-MainConfig configuration information included in the radio resource configuration dedicated information, And / or information for displaying the periodic information. Alternatively, the aforementioned information for calculating the amount of available data of the PDCP layer to the terminal may be preset.

The above-described MAC-MainConfig information element for each base station may include individual configuration parameters for a MAC entity for each base station or each cell group when a dual connection is established in the terminal. For example, the secondary base station MAC-MainConfig (MAC-MainConfigSeNB or MAC-MainConfigSCG) transmits buffer status report timers (for example, periodicBSR-Timer and / or retxBSR-Timer) included in the master base station MAC- Report timers.

As another example, a terminal may use a bearer split user plane structure to create a logical channel (or a logical channel) that is mapped to a split bearer configured to process data via the first and second base stations (or via one or more base stations) (Or each cell group) of the PDCP layer for each logical channel and allocates the available data amount of the PDCP layer for the corresponding logical channel equally to each logical channel group (Amount of usable data) can be calculated. To this end, in the RRC message, logical channel configuration information included in radio resource configuration dedicated information or radio resource configuration dedicated information, or MAC-MainConfig configuration information included in radio resource configuration dedicated information, Information for calculating the amount of available data of the layer and / or information for displaying it. Alternatively, the aforementioned information for calculating the amount of available data of the PDCP layer to the terminal may be preset.

As another example, a terminal may use a bearer split user plane structure to create a logical channel (or a logical channel) that is mapped to a split bearer configured to process data via the first and second base stations (or via one or more base stations) PDCP buffer status information (amount of usable data) for each base station (or each cell group) is calculated based on the ratio calculated based on the wireless quality status or the RRM measurement information between the terminal and each of the base stations can do. That is, the amount of available data of the PDCP layer can be calculated for each base station (or for each cell group) by allocating the available data amount of the PDCP layer for the logical channel in proportion or in inverse proportion to the radio quality status or RRM measurement information have. To this end, in the RRC message, logical channel configuration information included in radio resource configuration dedicated information or radio resource configuration dedicated information, or MAC-MainConfig configuration information included in radio resource configuration dedicated information, Information for calculating the amount of available data in the layer, measurement cycle, measurement event, and information for displaying the measurement event. Alternatively, the above-described information may be preset in the terminal.

As another example, a terminal may use a bearer split user plane structure to create a logical channel (or a logical channel) that is mapped to a split bearer configured to process data via the first and second base stations (or via one or more base stations) Logical channel group) based on the available data amount information of the terminal and the RLC layer peered to each base station. That is, the amount of available data of the PDCP layer for the logical channel is proportionally or inversely proportional to the available data amount information of the RLC layer peered to the first base station and the second base station, (Amount of usable data). To this end, in the RRC message, logical channel configuration information included in radio resource configuration dedicated information or radio resource configuration dedicated information, or MAC-MainConfig configuration information included in radio resource configuration dedicated information, Information for calculating the amount of available data of the layer and / or information for displaying it. Alternatively, the aforementioned information for calculating the amount of available data of the PDCP layer to the terminal may be preset.

As another example, a terminal may use a bearer split user plane structure to create a logical channel (or a logical channel) that is mapped to a split bearer configured to process data via the first and second base stations (or via one or more base stations) (Or a group of logical channels) of the PDCP layer for each logical channel in the PDCP layer for each base station, and transmits the ratio information or method information for allocating available data of the PDCP layer for the corresponding logical channel to each PDCP layer (Amount of usable data) of the buffer status information of the buffer. Specifically, for example, the UE can receive the above-described ratio information or allocation method information through a first base station (master base station) to which an RRC connection is established. Alternatively, the UE may receive the above-described ratio information or allocation method information through a second base station (secondary base station) confirmed by a first base station (master base station) to which an RRC connection is established. Alternatively, the terminal may receive the rate information or the allocation method information through the first base station, and the information may be transmitted by the second base station supporting the first base station through the first base station. To this end, in the RRC message, logical channel configuration information included in radio resource configuration dedicated information or radio resource configuration dedicated information, or MAC-MainConfig configuration information included in radio resource configuration dedicated information, Rate information for calculating the amount of available data of the layer and / or information for displaying it. Alternatively, the aforementioned information for calculating the amount of available data of the PDCP layer to the terminal may be preset. Alternatively, the above-described ratio information and the like may be received when a new MAC control element is defined. For example, the newly defined MAC control element may be a first (or second) base station that has received an acknowledgment by a first base station with an RRC connection established (or via a first base station with an acknowledgment of a second base station) May be transmitted via a second base station supporting the base station or via a second base station supporting the first base station.

The UE can transmit / submit data (PDU) from the intra-UE PDCP layer to the intra-UE RLC entity mapped to the RLC entity of each base station based on the ratio information received from the base station.

In this way, the UE can calculate the PDCP buffer status information for each BS according to each of the methods described above. The UE may transmit the buffer status report to each base station by summing the calculated PDCP buffer status information for each base station (or cell group) with the amount of available data of the RLC layer paired with each base station. That is, in the second embodiment, the PDCP buffer status report is transmitted separately from the existing buffer status report (BSR). However, the PDCP buffer status information included in the buffer status report transmitted for each base station is information calculated for each base station by each method described above. Each base station (or cell group) MAC entity in the terminal can transmit a buffer status report to each base station.

Therefore, each base station receives the amount of available data to be processed through each base station through the BSR, so that the uplink radio resource can be efficiently allocated according to the buffer size information of the received BSR, and the buffer status information of the PDCP layer Can be solved.

Third Example : A method of calculating available data for each base station Reporting  Way.

When one or more bearers are configured as split bearers as in the specific bearer shown in FIG. 2 or FIG. 3, the amount of available data for a logical channel (or a logical channel group) To be reported via an existing BSR (short BSR or Truncated BSR or Long BSR) MAC CE.

For example, a UE may use a bearer split user plane structure to provide a logical channel (or logical channel group) mapped to a split bearer configured to process data via a first base station and a second base station, The available data amount through the base station (or the first base station MAC entity in the master cell group or the first base station MAC entity in the terminal peered to the first base station MAC entity) may use the existing available data amount calculation method. That is, the UE can perform BSR reporting by summing the amount of available data of the PDCP layer for the existing logical channel in the UE with the amount of available data through the first base station and the amount of available data of the RLC layer for the first base station have. Then, the terminal transmits the RLC layer for the second base station in the terminal to the second base station (or the secondary cell group, the second base station MAC entity, or the second base station MAC entity in the terminal peered to the second base station MAC entity) The BSR reporting can be performed using the available data amount of the BSR. That is, the buffer status report transmitted to the second base station may not include the buffer status information (the amount of available data) of the PDCP layer. The UE adds the available data amount of the PDCP layer to the logical channel that is determined by the radio condition (quality) or mapped to the corresponding split bearer through the first base station for which the RRC connection is established to the available data amount through the first base station (Processing) the received information. For this purpose, the message transmitted from the base station to the mobile station may be an RRC message or a MAC CE. When the UE is configured to include the available data amount of the PDCP layer for the split bearer in the amount of available data through the first base station, the UE transmits the PDCP PDU for the corresponding bearer to the first peer RLC entity It can only be submitted as an RLC entity.

As another example, for a logical channel (or a logical channel group) that is mapped to a split bearer configured to process data via a first base station and a second base station using a bearer split user plane structure, The amount of available data through the base station (or the secondary cell group or the second base station MAC entity or the second base station MAC entity in the terminal peered to the second base station MAC entity) may use the existing available data amount calculation method. That is, the UE can perform the BSR reporting by summing the available data amount of the PDCP layer for the existing logical channel in the UE and the available data amount of the RLC layer for the second base station by the available data amount through the second base station have. And the terminal can perform BSR reporting using the available data amount of the RLC layer for the first base station in the terminal with the amount of available data through the first base station. That is, the buffer status report transmitted to the first base station may not include the buffer status information (the amount of available data) of the PDCP layer. The UE determines whether the RRC connection is established according to the radio condition (quality) or the RRC connection is established through the first base station (or the first base station upon confirmation of the second base station) or the first base station A second base station supporting a first base station or a second base station supporting a first base station aggregates the amount of available data in the PDCP layer for that logical channel via the first base station to the amount of available data via the second base station (Processing) the received information. For this purpose, a message transmitted from the base station to the mobile station may include new information in the RRC message or a new MAC CE may be defined and used. When the UE is configured to include the available data amount of the PDCP layer for the split bearer in the amount of available data through the second base station, the UE transmits the PDCP PDU for the corresponding bearer to the second peer RLC entity It can only be submitted as an RLC entity.

As another example, the terminal may use a Bearer Split user plane structure for a logical channel that is mapped to a split bearer configured to process data via the first and second base stations (or via one or more base stations) It is possible to select the base station to which the available data amount of the PDCP layer is to be allocated first based on the radio quality state or the RRM measurement information between the UE and each of the base stations. To this end, the available data amount of the PDCP layer is firstly allocated to the logical channel configuration information included in the radio resource configuration dedicated information or the radio resource configuration dedicated information or the MAC-MainConfig configuration information included in the radio resource configuration dedicated information on the RRC message Information for selecting a base station to be allocated first, measurement cycle, measurement event, and information for displaying the measurement event. Alternatively, the aforementioned information may be preset in the terminal.

Therefore, each base station receives the amount of available data to be processed through each base station through the BSR, so that each base station can efficiently allocate uplink radio resources in accordance with the requested buffer size. That is, by including the PDCP buffer status information only in the buffer status report transmitted to any one of the base stations, it is possible to solve the problem that the PDCP buffer status information is duplicated to the base station.

As described above, according to the present invention, even when different base stations of a specific bearer are configured to transmit data by merging radio resources through separate schedulers, each base station allocates radio resources to only the amount of usable data actually required So that there is an effect of efficiently allocating radio resources.

Hereinafter, operations of a terminal and a base station, in which all of the above-described embodiments can be performed, will be described once again with reference to the drawings.

11 is a flowchart illustrating an operation of a terminal according to another embodiment of the present invention.

According to an aspect of the present invention, there is provided a method for transmitting buffer status information, the method comprising: configuring one or more logical channels or logical channel groups to be duplexed with a first base station and a second base station; And transmitting the PDCP buffer status information of the channel group to the first base station or the second base station.

Referring to FIG. 11, a UE can configure dual connectivity for at least one logical channel or logical channel group mapped to a first BS and a second BS and a split bearer (S1110). That is, as shown in FIG. 2 and FIG. 3, the UE can form bearer with at least one base station, and at least one bearer can be configured separately from the first base station and the second base station.

The UE may transmit the logical channel mapped to the separately configured bearer or the PDCP buffer status information of the logical channel group including the logical channel to the first BS or the second BS in step S1120.

In transmitting the PDCP buffer status information, the UE can transmit the PDCP buffer status information separately or in an existing buffer status report according to each of the above embodiments. The PDCP buffer state information is distributed and transmitted to each base station as in the second embodiment or transmitted only in the buffer status report transmitted to any one base station as in the third embodiment .

For example, the PDCP buffer status information includes information on the amount of available data of the PDCP to be transmitted in the uplink, and may be transmitted to one or more of the first and second base stations separately from the buffer status report have. In addition, the PDCP buffer status information may be included in the MAC control element and transmitted.

As another example, the PDCP buffer status information may be distributed to the buffer status report transmitted to the first base station and the buffer status report transmitted to the second base station, respectively. In addition, the PDCP buffer status information may be distributed based on wireless quality, a preset ratio, and configuration information received from the first base station or the second base station. In configuring a logical channel or a logical channel group in the MAC entity, the terminal may include a buffer status report (BSR) timer for each base station or a cell group.

As another example, the PDCP buffer status information may be transmitted only in the buffer status report of either the buffer status report transmitted to the first base station or the buffer status report transmitted to the second base station.

In this way, the UE can transmit the PDCP buffer status information to the first base station or the second base station so that they are not duplicated, and the first base station and the second base station can efficiently allocate the radio resources.

12 is a flowchart illustrating an operation of a base station according to another embodiment of the present invention.

A method for receiving buffer state information in a first base station according to another embodiment of the present invention includes configuring a dual connection to a second base station and a terminal for one or more logical channels or logical channel groups mapped to a split bearer, And receiving PDCP buffer status information from the UE.

Referring to FIG. 12, the first base station can configure a dual connection with a terminal (S1210). That is, the first base station may configure a dual connection to the terminal together with the second base station for one or more logical channels or logical channel groups that are mapped to a split bearer. For example, the first base station may separate one or more bearers as shown in FIGS. 2 and 3 to form a dual connection with the second base station to the terminal.

The first base station may receive the PDCP buffer status information from the UE (S1220). The first base station allocates the uplink radio resource to the UE based on the received PDCP buffer status information and the buffer status report. In receiving the PDCP buffer status information, the first base station may separately receive according to each of the above embodiments, or receive the PDCP buffer status information in an existing buffer status report. When the PDCP buffer status report is received and included in the existing buffer status report, PDCP buffer status information distributed and included for each base station is received as in the second embodiment, or included in the buffer status report transmitted to the second base station as in the third embodiment But can be received only in the buffer status report transmitted to the first base station.

For example, the PDCP buffer status information may be received separately from the buffer status report. That is, the buffer status report does not include information on the amount of available data of the PDCP layer and can be received separately. The separately received PDCP buffer status information may be included in the MAC control element. As described above, a separate report including the PDCP buffer status information can be distinguished by a newly defined index.

As another example, the PDCP buffer status information is information distributed by the UE and can be received in the buffer status report. That is, the PDCP buffer state information of the first base station calculated according to the distribution of the PDCP buffer state information according to the second embodiment described above is included and can be received through the buffer state report.

As another example, the PDCP buffer status information may be received only in a buffer status report received by the first base station. That is, the buffer status report transmitted to the second base station may not include information on the amount of available data of the PDCP layer.

In this way, the first BS can calculate the radio resources to be allocated to the UE based on the received PDCP buffer status information and the existing buffer status report. As a concrete calculation method, the method described in each of the above-described embodiments can be used.

The first base station can allocate the calculated radio resource to the terminal and receive the uplink from the terminal.

The second base station can perform the same operation as the first base station. However, if the PDCP buffer status information is included only in the buffer status report transmitted to the first base station, the second base station can receive the buffer status report excluding the PDCP buffer status information.

A configuration of a terminal and a base station to which all embodiments of the present invention can be performed will be described with reference to the drawings.

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

The UE for transmitting buffer status information according to another embodiment of the present invention includes a controller 1320 configured to couple one or more logical channels or logical channel groups mapped to a split bearer to first and second base stations, And a transmitter 1330 that transmits PDCP buffer status information of one or more logical channels or logical channel groups mapped to the split bearer to the first base station or the second base station.

13, a user terminal 1300 according to another embodiment of the present invention includes a receiver 1310, a controller 1320, and a transmitter 1330.

The receiver 1310 receives downlink control information, data, and messages from the base station through the corresponding channel. That is, downlink information such as uplink radio resource allocation information can be received.

The controller 1320 controls operations of the terminals required to configure the dual connection with the first base station and the second base station, which are necessary to perform the above-described present invention. In addition, the controller 1320 can control the operation of the UE according to the PDCP buffer status information of the logical channel or the logical channel group configured by bearer separation in accordance with the above-described embodiments.

The transmitter 1330 may transmit the PDCP buffer status information to the first base station and the second base station. Specifically, the transmitter 1330 may separately transmit the PDCP buffer status report separately from the existing buffer status report according to each of the above-described embodiments. Alternatively, the transmission unit 1330 may transmit the PDCP buffer status information, and may include the distributed information in the buffer status report according to the distribution result. In this case, it may be transmitted to one or more base stations of the first base station or the second base station. In addition, the transmitter 1330 transmits uplink control information, data, and a message through a corresponding channel.

In addition, the terminal can perform all necessary operations in performing each of the above embodiments.

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

The first BS receiving the buffer status information according to another embodiment of the present invention includes a controller 1410 configured to establish a dual connection to the second BS and the MS for one or more logical channels or logical channel groups mapped to the split bearer, And a receiving unit 1430 for receiving the PDCP buffer status information from the UE.

Referring to FIG. 14, a base station 1400 according to another embodiment of the present invention includes a controller 1410, a transmitter 1420, and a receiver 1430.

The controller 1410 may control the operation of the base station together with the second base station in order to configure a dual connection to the terminal. In addition, the controller 1410 can allocate uplink radio resources based on the PDCP buffer status information and the buffer status report received from the UE according to each embodiment.

The transmitter 1420 can transmit downlink control information and a message to the UE and can transmit information such as a distribution ratio necessary for the UE to distribute the PDCP buffer status information.

The receiving unit 1430 can receive the PDCP buffer status information from the UE. Specifically, the receiving unit 1430 may separately receive the PDCP buffer status information or receive the PDCP buffer status information in the buffer status report according to each of the embodiments of the present invention described above. Also, the receiver 1430 can receive the uplink signals, messages, or data necessary for carrying out the present invention.

In addition, the base station can perform all necessary operations in performing each of the above-described embodiments.

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 (24)

A method for a terminal to transmit buffer status information,
Configuring one or more logical channels or logical channel groups mapped to the split bearer to be duplexed with the first base station and the second base station; And
And transmitting PDCP buffer status information of the at least one logical channel or logical channel group to the first base station or the second base station. The method according to claim 1,
The PDCP buffer status information may include:
Wherein the UE includes information on an amount of available data of a PDCP to be transmitted in an uplink and is transmitted to one or more base stations of the first base station and the second base station separately from a buffer status report. 3. The method of claim 2,
The PDCP buffer status information may include:
MAC control element. The method according to claim 1,
The PDCP buffer status information may include:
A buffer status report transmitted to the first base station, and a buffer status report transmitted to the second base station. 5. The method of claim 4,
The PDCP buffer status information may include:
Based on configuration information received from the first base station or the second base station. The method according to claim 1,
Wherein configuring the logical channel or logical channel group comprises:
And a buffer status report (BSR) timer for each base station or each cell group. The method according to claim 1,
The PDCP buffer status information may include:
Wherein the buffer state report is transmitted only to a buffer status report transmitted to the first base station or a buffer status report transmitted to the second base station. A method for a first base station to receive buffer status information,
Configuring a dual connection to a second base station and a terminal for one or more logical channels or logical channel groups mapped to a split bearer; And
And receiving PDCP buffer status information from the terminal. 9. The method of claim 8,
The PDCP buffer status information may include:
A method that is received separately from a buffer status report. 10. The method of claim 9,
The PDCP buffer status information may include:
MAC control element. 9. The method of claim 8,
The PDCP buffer status information may include:
The information being distributed by the terminal and being included in a buffer status report. 9. The method of claim 8,
The PDCP buffer status information may include:
And is included only in a buffer status report received at the first base station. A terminal for transmitting buffer status information,
A control unit configured to couple one or more logical channels or logical channel groups mapped to the split bearer to the first base station and the second base station; And
And transmitting the PDCP buffer state information of the at least one logical channel or logical channel group to the first base station or the second base station. 14. The method of claim 13,
The PDCP buffer status information may include:
Wherein the information on the amount of available data of the PDCP to be transmitted in the uplink is transmitted to one or more base stations of the first base station and the second base station separately from the buffer status report. 15. The method of claim 14,
The PDCP buffer status information may include:
Wherein the MAC control element is included and transmitted. 14. The method of claim 13,
The PDCP buffer status information may include:
A buffer status report transmitted to the first base station, and a buffer status report transmitted to the second base station, respectively. 17. The method of claim 16,
The PDCP buffer status information may include:
And is distributed based on the configuration information received from the first base station or the second base station. 14. The method of claim 13,
Wherein,
And configures the logical channel or logical channel group including a buffer status report (BSR) timer for each base station or cell group. 14. The method of claim 13,
The PDCP buffer status information may include:
The buffer status report transmitted to the first base station or the buffer status report transmitted to the second base station. A first base station for receiving buffer status information,
A controller for establishing a dual connection to the second base station and the terminal for one or more logical channels or logical channel groups mapped to the split bearer; And
And a receiver for receiving PDCP buffer status information from the UE. 21. The method of claim 20,
The PDCP buffer status information may include:
And is received separately from the buffer status report. 22. The method of claim 21,
The PDCP buffer status information may include:
And the MAC control element. 21. The method of claim 20,
The PDCP buffer status information may include:
The information being distributed by the terminal and being included in a buffer state report. 21. The method of claim 20,
The PDCP buffer status information may include:
And is included only in a buffer status report received at the first base station.

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