KR102101517B1 - Method and apparatus for performing activation/deactivation of serving cell in wireless communication system using dual connectivity - Google Patents

Abstract

A method and apparatus for activating / deactivating a serving cell in a wireless communication system using a dual connection method is proposed. In a wireless communication system, a method of activating / deactivating a serving cell by a terminal establishes a dual connection with two or more different base stations based on dual connectivity configuration information received through a radio resource control (RRC) message from the base station. Configuring, receiving activation / deactivation information for a secondary serving cell configured in the terminal from each of the different base stations, and a secondary timing advance group including a secondary serving cell provided by the base station ) Or selectively applying the activation / deactivation information to the secondary serving cell configured in the terminal based on the information about the base station providing the secondary serving cell configured in the terminal.

Description

METHOD AND APPARATUS FOR PERFORMING ACTIVATION / DEACTIVATION OF SERVING CELL IN WIRELESS COMMUNICATION SYSTEM USING DUAL CONNECTIVITY in a wireless communication system using a dual connection method

The present invention relates to a method and apparatus for performing activation / deactivation of secondary serving cells when a terminal is dual connected through two or more different base stations in a wireless communication system.

In a wireless communication system, a terminal may perform wireless communication through two or more base stations among base stations constituting at least one serving cell. This is called dual connectivity. In other words, a dual connection is an operation in which a terminal configured with at least two different network points and an RRC connection state (Radio Resource Control connected state) consumes radio resources provided by the network points. can do. Here, at least two or more different network points may be a plurality of base stations that are physically or logically separated, one of which is a master base station (MeNB), and the other base stations are secondary eNB (SenB: Secondary eNB) base stations. Can be

In a dual connection, each base station transmits downlink data through a bearer configured for one terminal and receives uplink data. At this time, one bearer may be configured through one base station, or may be configured through two or more different base stations. In addition, in a dual connection, each base station may be configured with at least one serving cell (Serving Cell), and each serving cell may be operated in an activated or inactive state. At this time, a master base station is configured with a primary serving cell (PCell: Primary (serving) Cell) configurable in an existing element aggregation (CA: Carrier Aggregation) method, and a secondary base station with a secondary serving cell (SCell: Secondary (serving)) Cell). Here, carrier aggregation is a technique for efficiently using a fragmented small band, where one base station bundles a plurality of physically continuous or non-continuous bands in the frequency domain to logically use a large band. This is to achieve the same effect as using a band.

When the terminal is connected to one base station, the base station transmits activation / deactivation indicators for all secondary serving cells configured to itself to the terminal in order to optimize the battery consumption of the terminal, and the terminal is based on the indicator received from the base station Activates or deactivates the departmental serving cells that are configured to itself. However, in the case of a dual connection, when the master base station and the secondary base station respectively transmit activation / deactivation indicators for the secondary serving cells configured to them, the indicator activates all secondary serving cells configured in the corresponding terminal. Since the / deactivation indicator is included, there is a problem that the activation / deactivation of the secondary serving cell provided by another base station is indicated. However, since the MAC (Medium Access Control) scheduler of each base station exists in each base station and operates independently of each other in a dual connection, it is not possible to determine whether to activate / deactivate the serving cells in another base station. Therefore, there is a need for a method capable of solving the above-mentioned problems.

The technical problem of the present invention is that in a wireless communication system, a base station connected to a terminal dually transmits activation / deactivation information for secondary serving cells to a terminal, while maintaining the existing message format while the MAC scheduler of each base station exchanges information between each base station. It is to provide a method and apparatus for activating / deactivating a serving cell in a wireless communication system using a dual connection method that can be operated independently without any need.

According to an aspect of the present invention, a method of activating / deactivating a serving cell by a terminal in a wireless communication system is based on dual connectivity configuration information received through a radio resource control (RRC) message from a base station. Configuring a dual connection with other base stations, receiving activation / deactivation information for a secondary serving cell configured in the terminal from each of the different base stations, and a secondary serving cell provided by the base station. Selectively applying the activation / deactivation information to the secondary serving cell configured in the terminal based on the information on the secondary timing advance group or the base station providing the secondary serving cell configured in the terminal It may include.

According to another aspect of the present invention, the activation / deactivation apparatus of a serving cell receives dual connectivity configuration information for dual connectivity with two or more different base stations through a Radio Resource Control (RRC) message from the base station. , A receiving unit for receiving activation / deactivation information for a secondary serving cell configured in the terminal from each of the different base stations, for a secondary timing advance group including a secondary serving cell provided by the base station The determination unit and the determination unit for determining which of the base stations is the secondary serving cell provided by each of the base station based on the information or information on the base station providing the secondary serving cell configured in the terminal. Selectively apply the activation / deactivation information to the secondary serving cell configured in the terminal according to the result. May include an application part.

As each base station generates and transmits the MAC CE information to the UE and transmits it to the UE, the MAC scheduler can be independently operated without exchanging information between the base stations because the existing message format can be transmitted independently of each other.

1 is a diagram showing a network structure of a wireless communication system.
2 is a block diagram showing a radio protocol structure for a user plane.
3 is a block diagram showing a radio protocol structure for a control plane.
4 is a diagram showing the structure of a bearer service in a wireless communication system.
5 is a diagram illustrating a dual connection situation of a terminal.
6 is a diagram showing the structure of a user plane for dual connectivity.
7 to 11 are diagrams showing protocol structures of base stations in downlink transmission of user plane data.
12 is a diagram showing the structure of a MAC PDU.
13 is a diagram showing the structure of a MAC subheader.
14 is a diagram showing the structure of MAC CE.
15A is a diagram illustrating a method of transmitting activation / deactivation information for secondary serving cells according to an embodiment of the present invention.
15B is a diagram illustrating a method of transmitting activation / deactivation information when the special secondary serving cell has the same activation characteristics as the primary serving cell according to an embodiment of the present invention.
15C is a diagram illustrating a method of transmitting activation / deactivation information for secondary serving cells according to another embodiment of the present invention.
16 is a diagram showing a method of transmitting activation / deactivation information for secondary serving cells according to another embodiment of the present invention.
17 is a flowchart illustrating an operation of a terminal receiving activation / deactivation information for secondary serving cells according to an embodiment of the present invention.
18 is a flowchart illustrating an operation of a base station transmitting activation / deactivation information for secondary serving cells according to an embodiment of the present invention.
19 is a flowchart illustrating an operation of a master base station transmitting activation / deactivation information for secondary serving cells according to another embodiment of the present invention.
20 is a flowchart illustrating the operation of a secondary base station transmitting activation / deactivation information for secondary serving cells according to another embodiment of the present invention.
21 is a block diagram showing an example of an activation / deactivation information transmitting and receiving device for secondary serving cells according to the present invention.

Hereinafter, in the present specification, contents related to the present invention will be described in detail through exemplary drawings and examples together with the contents of the present invention. It should be noted that in adding reference numerals to the components of each drawing, the same components have the same reference numerals as possible even though they are displayed on different drawings. In addition, in describing embodiments of the present specification, when it is determined that detailed descriptions of related well-known structures or functions may obscure the subject matter of the present specification, detailed descriptions thereof will be omitted.

In addition, this specification is described for a wireless communication network, the work performed in the wireless communication network is performed in the process of controlling the network and transmitting data in a system (for example, a base station) that is in charge of the wireless communication network, or The operation can be performed at the terminal coupled to the network.

1 is a diagram showing a network structure of a wireless communication system.

FIG. 1 shows a network structure of an Evolved-Universal Mobile Telecommunications System (E-UMTS) as an example of a wireless communication system. The E-UMTS system may be an evolved-UMTS terrestrial radio access (E-UTRA) or a long term evolution (LTE) or an advanced (LTE-A) system. Wireless communication systems include Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier-FDMA (SC-FDMA), and OFDM-FDMA , OFDM-TDMA, OFDM-CDMA can use a variety of multiple access techniques.

Referring to Figure 1, E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) is a base station that provides a user equipment (UE: User Equipment, 10) a control plane (CP: Control Plane) and a user plane (UP: User Plane) (eNB: evolved NodeB, 20).

The terminal 10 may be fixed or mobile, and may be called other terms such as a mobile station (MS), an advanced MS (AMS), a user terminal (UT), a subscriber station (SS), or a wireless device (Wireless Device). have.

Base station 20 generally refers to a station (station) that communicates with the terminal 10, BS (Base Station), BTS (Base Transceiver System), access point (Access Point), femto base station (femto-eNB), pico It may be referred to as other terms such as a base station (pico-eNB), a home base station (Home eNB), and a relay. The base stations 20 are physically connected through an optical cable or a DSL (Digital Subscriber Line), and can exchange signals or messages with each other through an Xn interface. 1 shows an example in which the base stations 20 are connected through an X2 interface.

Hereinafter, the description of the physical connection will be omitted and the logical connection will be described. As shown in Figure 1, the base station 20 is connected to the Evolved Packet Core (EPC) 30 through the S1 interface. More specifically, the base station 20 is connected to the Mobility Management Entity (MME) through the S1-MME interface, and is connected to the Serving Gateway (S-GW) through the S1-U interface. The base station 20 exchanges MME with the context information of the terminal 10 and the information for supporting the mobility of the terminal 10 through the S1-MME interface. In addition, data to be serviced to and from each terminal 10 is exchanged with the S-GW through the S1-U interface.

The EPC 30 is not shown in FIG. 1, but includes MME, S-GW and P-GW (Packet data network-Gateway). The MME has access information of the terminal 10 or information about the capability of the terminal 10, and this information is mainly used for mobility management of the terminal 10. S-GW is a gateway with E-UTRAN as an endpoint, and P-GW is a gateway with PDN (Packet Data Network) as an endpoint.

E-UTRAN and EPC (30) are integrated to be called Evolved Packet System (EPS), and all traffic flows from the radio link that the terminal 10 connects to the base station 20 to the PDN connecting to the service entity are IP. (Internet Protocol).

The radio interface between the terminal 10 and the base station 20 is called "Uu interface". The layers of the radio interface protocol between the terminal 10 and the network are the first layer (L1) defined in a 3GPP (3rd Generation Partnership Project) type wireless communication system (UMTS, LTE, LTE-Advanced, etc.), It may be divided into a second layer (L2) and a third layer (L3). Among them, the physical layer belonging to the first layer provides an information transfer service using a physical channel, and the radio resource control (RRC) layer located in the third layer exchanges RRC messages to the terminal. Radio resources are controlled between (10) and the network.

2 is a block diagram showing a radio protocol architecture for a user plane, and FIG. 3 is a block diagram showing a radio protocol architecture for a control plane. The user plane is a protocol stack for transmitting user data, and the control plane is a protocol stack for transmitting control signals.

2 and 3, a physical layer (PHY (physical) layer) of the terminal and the base station provides an information transfer service to an upper layer using a physical channel, respectively. The physical layer is connected to the upper layer, the medium access control (MAC) layer, and through a transport channel. Data is transferred through the transport channel between the MAC layer and the physical layer. Transport channels are classified according to how data is transmitted through a wireless interface. In addition, data is transferred through physical channels between different physical layers (that is, between the physical layers of the terminal and the base station). The physical channel can be modulated by an orthogonal frequency division multiplexing (OFDM) method, and utilizes time, frequency, and space generated by a plurality of antennas as radio resources.

For example, PDCCH (Physical Downlink Control CHannel) among physical channels informs a UE of resource allocation of PCH (Paging CHannel) and DL-SCH (DownLink Shared CHannel) and Hybrid Automatic Repeat Request (HARQ) information related to DL-SCH, An uplink scheduling grant indicating resource allocation of uplink transmission to the terminal may be carried. In addition, the PCFICH (Physical Control Format Indicator CHannel) informs the UE of the number of OFDM symbols used for the PDCCHs and is transmitted every subframe. In addition, PHICH (Physical Hybrid ARQ Indicator CHannel) carries an HARQ ACK / NAK signal in response to uplink transmission. In addition, Physical Uplink Control CHannel (PUCCH) carries uplink control information such as HARQ ACK / NAK, scheduling request, and CQI for downlink transmission. In addition, PUSCH (Physical Uplink Shared CHannel) carries UL-SCH (UpLink Shared CHannel). The PUSCH may include channel state information (CSI) information such as HARQ ACK / NACK and CQI, if necessary according to the configuration and request of the base station.

The MAC layer can perform multiplexing or demultiplexing between a logical channel and a transport channel and a transport block provided as a physical channel on a transport channel of a MAC service data unit (MAC SDU) belonging to the logical channel. The MAC layer provides a service to a radio link control (RLC) layer through a logical channel. The logical channel can be divided into a control channel for transmitting control region information and a traffic channel for transferring user region information. For example, as services provided from a MAC layer to a higher layer, there is data transfer or radio resource allocation.

The functions of the RLC layer include concatenation, segmentation and reassembly of RLC SDUs. The RLC layer is a transparent mode (TM: Transparent Mode), an unacknowledged mode (UM), and an acknowledgment mode (AM: AM) to ensure various quality of service (QoS) required by a radio bearer (RB). It provides three operation modes: Acknowledged Mode.

Generally, the transparent mode is used to establish an initial connection.

The unverified mode is for real-time data transmission such as data streaming or Voice over Internet Protocol (VoIP), and is a mode focused on speed rather than reliability of data. On the other hand, the verification mode is a mode focused on the reliability of data, and is suitable for data transmission that is less sensitive to large data transmission or transmission delay. The base station determines the RLC mode in the RB corresponding to each EPS bearer based on QoS (Quality of Service) information of each EPS bearer connected to the UE and configures parameters in the RLC to satisfy QoS.

RLC SDUs are supported in various sizes, for example, in units of bytes. RLC Protocol Data Units (PDUs) are defined only when a transmission opportunity is notified from a lower layer (eg, MAC layer) and are transmitted to a lower layer. The transmission opportunity can be informed with the size of the total RLC PDUs to be transmitted. In addition, the transmission opportunity and the size of the total RLC PDUs to be transmitted may be separately reported.

The functions of the Packet Data Convergence Protocol (PDCP) layer in the user plane include user data transfer, header compression and ciphering, and control plane data transfer and encryption / integrity protection.

Referring to FIG. 3, the RRC layer is in charge of controlling logical channels, transport channels, and physical channels in connection with configuration, re-configuration, and release of RBs. Radio bearer (RB) refers to a logical path provided by a first layer (PHY layer) and a second layer (MAC layer, RLC layer, PDCP layer) for data transmission between a terminal and a network. RB configuration means a process of defining characteristics of a radio protocol layer and a channel to provide a specific service, and setting each specific parameter and operation method. RB may be divided into SRB (Signaling RB) and DRB (Data RB). SRB is used as a path for transmitting RRC messages and non-access stratum (NAS) messages in the control plane, and DRB is used as a path for transmitting user data in the user plane.

The NAS (Non-Access Stratum) layer located above the RRC layer performs functions such as session management and mobility management. If there is an RRC connection (RRC Connection) between the RRC layer of the terminal and the RRC layer of the E-UTRAN, the terminal is in the RRC connected state (RRC connected state), otherwise it is in the RRC idle state (RRC idle state) do.

In order for the terminal to transmit user data (eg, IP packet) to the external Internet network or to receive user data from the external Internet network, it exists between mobile communication network entities existing between the terminal and the external Internet network. Resources must be allocated to multiple paths. The path through which resources are allocated and transmitted and received between the mobile communication network entities is called a bearer.

4 is a diagram showing the structure of a bearer service in a wireless communication system.

4 shows a path in which an end-to-end service is provided between the terminal and the Internet network. Here, the end-to-end service refers to a service in which a terminal (UE) requires a path between the terminal and the P-GW (EPS Bearer) and a path between the P-GW and the outside (External Bearer) for the Internet network and data service. . Here, the external path is a bearer between the P-GW and the Internet network.

When the terminal delivers data to the external Internet network, the terminal first transmits data to the base station (eNB) through the RB. Then, the base station transmits the data received from the terminal to the S-GW through the S1 bearer. The S-GW delivers the data received from the base station to the P-GW through the S5 / S8 bearer, and finally the data is delivered to the destination existing in the P-GW and the external Internet network through an external bearer.

Likewise, in order to transmit data from the external Internet network to the terminal, it can be delivered to the terminal through each bearer in the reverse direction as described above.

In this way, in a wireless communication system, each bearer is defined for each interface, thereby guaranteeing independence between the interfaces. The bearer in each interface will be described in more detail as follows.

The bearer provided by the wireless communication system is collectively called an Evolved Packet System (EPS) bearer. The EPS bearer is a transmission path established between the UE and the P-GW to transmit IP traffic with a specific QoS. The P-GW can receive IP flows from the Internet or send IP flows to the Internet. Each EPS bearer is set with QoS decision parameters indicating characteristics of the delivery path. One or more EPS bearers may be configured per UE, and one EPS bearer uniquely expresses a concatenation of one E-RAB and one S5 / S8 bearer.

The radio bearer (RB) exists between the terminal and the base station to deliver packets of the EPS bearer. A specific RB has a one-to-one mapping relationship with a corresponding EPS bearer / E-RAB (E-UTRAN Radio Access Bearer).

The S1 bearer is a bearer existing between the S-GW and the base station, and delivers E-RAB packets.

The S5 / S8 bearer is a bearer of the S5 / S8 interface. Both S5 and S8 are bearers that exist on the interface between S-GW and P-GW. The S5 interface exists when the S-GW and the P-GW belong to the same operator, and the S8 interface belongs to the provider that the S-GW roams into (Visited PLMN), and the operator that the P-GW originally subscribed to (Home) PLMN).

The E-RAB uniquely expresses the concatenation of the S1 bearer and the corresponding RB. When there is one E-RAB, a one-to-one mapping is established between the corresponding E-RAB and one EPS bearer. That is, one EPS bearer corresponds to one RB, S1 bearer, and S5 / S8 bearer, respectively. The S1 bearer is a bearer at the interface between the base station and the S-GW.

RB means two types of data: RB (Data Radio Bearer) and signaling RB (Signaling Radio Bearer), but in the present invention, RB is a DRB provided in the Uu interface to support a user's service. . Therefore, RB expressed without distinction is distinct from SRB. RB is a path through which data of the user plane is transmitted, and SRB is a path through which data of the control plane such as an RRC layer and NAS control messages is transmitted. There is a one-to-one mapping between RB, E-RAB and EPS bearer. The base station maps the DRB and the S1 bearer on a one-to-one basis and stores it to create a DRB that links both the uplink and the downlink. The S-GW maps the S1 bearer and the S5 / S8 bearer on a one-to-one basis to store the S1 bearer and the S5 / S8 bearer that bind both the uplink and the downlink, and stores them.

EPS bearer types include a default bearer and a dedicated bearer. When the terminal accesses the wireless communication network, an IP address is assigned and a PDN connection is generated, and at the same time, a default EPS bearer is generated. That is, a default bearer is first created when a new PDN connection is created. When a user uses a service (for example, the Internet) through the default bearer and then uses a service (for example, VoD, etc.) that cannot properly provide QoS with the default bearer, on-demand A dedicated bearer is created. In this case, the dedicated bearer may be set to a different QoS from the bearer already set. QoS decision parameters applied to a dedicated bearer are provided by PCRF (Policy and Charging Rule Function). When creating a dedicated bearer, the PCRF can receive the user's subscription information from the Subscriber Profile Repository (SPR) to determine QoS decision parameters. For example, up to 15 dedicated bearers may be generated, and 4 of the 15 are not used in the LTE system. Therefore, up to 11 dedicated bearers can be created.

EPS bearer includes QCI (QoS Class Identifier) and ARP (Allocation and Retention Priority) as basic QoS decision parameters. EPS bearers are divided into GBR (Guaranteed Bit Rate) bearers and non-GBR bearers according to the QCI resource type. The default bearer is always set as a non-GBR type bearer, and the dedicated bearer can be set as a GBR type or a non-GBR type bearer. The GBR bearer has GBR and MBR (Maximum Bit Rate) as QoS decision parameters in addition to QCI and ARP. After the QoS that the wireless communication system should provide as a whole is defined as an EPS bearer, each QoS is defined for each interface. Each interface sets a bearer according to the QoS that it should provide.

5 is a diagram illustrating an example of a dual connection situation of a terminal.

In FIG. 5, as an example, the UE 550 enters an overlapping region where the service area of the macro cell F2 in the master base station 500 and the service area of the small cell F1 in the secondary base station 510 overlap. The case is shown.

In this case, in order to support additional data service through the small cell F1 in the secondary base station 510 while maintaining the existing wireless connection and data service connection through the macro cell F2 in the master base station 500, the network A dual connection is configured for the terminal 550. Accordingly, user data arriving at the master base station 500 may be transmitted to the terminal through the secondary base station 510. Specifically, the F2 frequency band is allocated to the master base station 500, and the F1 frequency band is allocated to the secondary base station 510. The terminal 550 may receive the service through the F2 frequency band from the master base station 500, and may receive the service through the F1 frequency band from the secondary base station 510. In the above example, the master base station 500 uses the F2 frequency band, and the secondary base station 510 is described as using the F1 frequency band, but the present invention is not limited thereto, and the master base station 500 and the secondary base station ( 510) All the same F1 or F2 frequency bands may be used.

6 is a diagram showing the structure of a user plane for dual connectivity.

The dual connectivity consists of any terminal, one master base station (MeNB) and at least one secondary base station (SeNB). The dual connection may be divided into three options as illustrated in FIG. 6 according to a method of dividing user plane data. In FIG. 6, for example, the concept of each of the three options for downlink transmission of user plane data is illustrated.

First option: This is a case where the S1-U interface has an endpoint in the secondary base station as well as the master base station. In this case, each base station (MeNB and SeNB) transmits downlink data through an EPS bearer configured for one UE (EPS bearer # 1 for a master base station and EPS bearer # 2 for a secondary base station). This is also referred to as CN split because user plane data is split in the core network (CN).

Second option: When the S1-U interface has an endpoint only at the master base station. In this case, the S1-U interface has an endpoint only at the master base station, but the bearer does not differentiate and only one bearer is mapped for each base station.

Third option: When the S1-U interface has an endpoint only in the MeNB. In this case, it is also called a bear split because the bearer differentiates. In a bearer split, data is divided into two flows (or more flows) and transmitted because one bearer is divided into multiple base stations. Since information is transmitted through a plurality of flows, the bearer split is called multi-flow, multiple-node (eNB) transmission, and inter-eNB carrier aggregation. Also.

On the other hand, when the endpoint of the S1-U interface is the master base station (ie, the second or third option) in terms of the protocol structure, the protocol layer in the secondary base station must support the segmentation or re-segmentation process. This is because the physical interface and the segmentation process are closely related, and when using a non-ideal backhaul, the segmentation or re-segmentation process must be the same as the node transmitting the RLC PDU. Therefore, considering the protocol structures for dual connectivity at the RLC layer or higher, the following are described.

1. PDCP layer is independently present in each base station. This is also called an independent PDCP type. In this case, each base station can use the operation of the existing LTE layer 2 protocol in the bearer as it is. This can be applied to all of the first to third options.

2. This is a case where the RLC layer is independently present in each base station. This is also called an independent RLC type. In this case, the S1-U interface uses the master base station as an endpoint, and the PDCP layer exists only in the master base station. In the case of the bearer split (the third option), the RLC layer is separated at both the network and the terminal side, and an independent RLC bearer exists for each RLC layer.

3. It is the case that the RLC layer is divided into the 'master RLC' layer of the master base station and the 'slave RLC' layer of the secondary base station. This is also called a master-slave RLC type. In this case, the S1-U interface has a master base station as an end point, and some of the PDCP layer and the RLC layer (master RLC layer) exist in the master base station, and a portion of the RLC layer (slave RLC layer) exists in the secondary base station. In the terminal, there is only one RLC layer paired with the master RLC layer and the slave RLC layer.

Accordingly, the dual connection may be classified as shown in FIGS. 7 to 11 by the combination of the above-described options and types.

7 to 11 are diagrams showing protocol structures of base stations in downlink transmission of user plane data.

First, referring to FIG. 7, a case where an S1-U interface has an endpoint in a secondary base station as well as a master base station and a PDCP layer is independently present in each base station (in the case of an independent PDCP type) is illustrated. In this case, the PDCP layer, the RLC layer, and the MAC layer exist in the master base station and the secondary base station, respectively, and each base station transmits downlink data through each EPS bearer configured for the UE.

In this case, the master base station does not need to buffer or process packets transmitted by the secondary base station, and has the advantage of having little or no impact on RDCP / RLC and GTP-U / UDP / IP. In addition, since there is less demand between the backhaul link between the master base station and the secondary base station, and there is no need to control the flow between the master base station and the secondary base station, the master base station does not need to route all traffic, and the secondary base station for the dual connected terminal Has the advantage of being able to support local break-out and content caching.

On the other hand, referring to Figure 8, the S1-U interface has an endpoint only in the master base station, is not a bearer split, and the PDCP layer is independently present in each base station (independent PDCP type) is illustrated. In this case, the PDCP layer, the RLC layer, and the MAC layer exist in the master base station and the secondary base station, respectively, but the PDCP layer of the master base station is connected to the PDCP layer of the secondary base station through the Xn interface. Here, the Xn interface may be an X2 interface defined between base stations in the LTE system.

In this case, the mobility of the secondary base station is hidden in the core network, has little or no effect on RDCP / RLC and GTP-U / UDP / IP, and has the advantage of processing only packets routed to the secondary base station without buffering. .

On the other hand, referring to Figure 9, the S1-U interface has an endpoint only in the master base station, and is not a bearer split, and an RLC layer independently exists in each base station (in the case of an independent RLC type). In this case, the PDCP layer, the RLC layer, and the MAC layer exist in the master base station, but only the RLC layer and the MAC layer exist in the secondary base station. The PDCP layer of the master base station is divided into bearer levels, one of which is connected to the RLC layer of the secondary base station through the Xn interface.

In this case, the mobility of the secondary base station is hidden in the core network, and there is an advantage that the master base station does not have a security effect requiring encryption. In addition, the master base station can pass the RLC processing to the secondary base station, there is an advantage that there is little or no effect on the RLC.

On the other hand, referring to FIG. 10, the case where the S1-U interface has an endpoint only in the master base station, is a bearer split, and the RLC layer independently exists in each base station (in the case of an independent RLC type). In this case, the PDCP layer, the RLC layer, and the MAC layer exist in the master base station, and only the RLC layer and the MAC layer exist in the secondary base station. The PDCP layer, the RLC layer, and the MAC layer of the master base station are separated at a bearer level, and one of the PDCP layers is connected to one of the RLC layers of the master base station, and is connected to the RLC layer of the secondary base station through the Xn interface.

In this case, the mobility of the secondary base station is hidden in the core network, there is no security effect requiring encryption at the master base station, and data forwarding between the secondary base stations is not required when the secondary base station is changed. In addition, the master base station can pass RLC processing to the secondary base station, or there is little or no effect on the RLC, and if possible, the radio resource can be utilized through the master base station and the secondary base station for the same bearer. Since the master base station can be used, there is an advantage that there is less requirement for mobility of the secondary base station.

On the other hand, referring to FIG. 11, when the S1-U interface has an endpoint only at the master base station, is a bearer split, and the RLC layer of the master base station is the master RLC layer and the secondary base station RLC layer is the slave RLC layer (master-slave RLC type) ). In this case, the PDCP layer, the RLC layer, and the MAC layer exist in the master base station, and only the RLC layer and the MAC layer exist in the secondary base station. In addition, the PDCP layer, the RLC layer and the MAC layer of the master base station are separated into bearer levels, and one of the RLC layers is connected to the RLC layer (slave RLC layer) of the secondary base station through the Xn interface as a master RLC layer.

In this case, the mobility of the secondary base station is hidden in the core network, there is no security effect requiring encryption at the master base station, and data forwarding between the secondary base stations is not required when the secondary base station is changed. In addition, since there is no or little effect on RLC, if possible, the radio resource can be utilized through the master base station and the secondary base station for the same bearer, and when moving the secondary base station, the master base station can be used in the meantime, thereby requiring the mobility of the secondary base station. It has the advantage of having fewer items. In addition, the packet loss between the master base station and the secondary base station can be covered by the ARQ of the RLC.

Hereinafter, activation and deactivation of a secondary serving cell during carrier aggregation (CA) in a wireless communication system will be described in more detail.

When the terminal configures the CA, the terminal has one RRC connection with the network. This is the same even when a double connection is configured. When establishing, re-establishing, or handing over an RRC connection, a specific serving cell provides non-access stratum (NAS) mobility information (eg, Tracking Area ID (TAI)). Hereinafter, the specific serving cell is referred to as a primary serving cell (PCell). The primary serving cell may be composed of a DL PCC (Downlink Primary Component Carrier) and a UL PCC (Uplink Primary Component Carrier).

Meanwhile, secondary cells (SCells) may be configured in the form of a set of serving cells together with a main serving cell according to a UE's hardware capability (UE capability). The secondary serving cell may be composed of only DL downlink secondary component carrier (SCC), or may be configured in pair with UL uplink secondary component carrier (SCC).

The serving cell set is composed of one main serving cell and at least one secondary serving cell. The primary serving cell can be changed only through a handover procedure and is used for PUCCH transmission. The primary serving cell cannot be transitioned to an inactive state, but the secondary serving cell can be transitioned to an inactive state.

The RRC reset procedure is triggered when a radio link failure (RLF) is experienced in the primary serving cell. However, the RLF of the secondary serving cell is not triggered.

Adding, removing, or reconfiguring a secondary serving cell in a serving cell set is performed through a dedicated signaling RRC reconfiguration procedure. When a new secondary serving cell is added to the serving cell set, the RRC reconfiguration message includes system information for the new secondary serving cell and is transmitted. Therefore, in the case of a secondary serving cell, a monitoring operation for changing system information is not required.

As described above, in order to optimize the battery consumption of the terminal when a CA is configured in the terminal, an activation / deactivation mechanism for a secondary serving cell is supported. When the secondary serving cell is in an inactive state, the UE does not need to receive a PDCCH or PDSCH corresponding to the secondary serving cell, and cannot transmit any data through an uplink corresponding to the secondary serving cell. Also, CQI (Channel Quality Indicator) measurement operation should not be performed. Conversely, if the secondary serving cell is active, the UE must receive the PDCCH and PDSCH. However, this is performed only when the corresponding terminal is configured to monitor the PDCCH for the secondary serving cell. In addition, it should be possible to perform CQI measurement operation.

The activation / deactivation mechanism is based on a combination of a MAC control element (CE) and a deactivation timer. MAC CE indicates whether to enable / disable each secondary serving cell with one bit, '0' deactivates, and '1' denotes activation. The MAC CE may independently indicate whether to enable / disable the secondary serving cells through bits corresponding to each secondary serving cell, which may be configured in the form of a bitmap.

The deactivation timer is configured and maintained for each secondary serving cell, but all secondary serving cells have a common deactivation timer value. The deactivation timer value is configured through RRC signaling.

If the UE receives an RRC reconfiguration message that does not include mobility control information (MCI), if there is a secondary serving cell added to the RRC reconfiguration message, the initial state of the secondary serving cell is 'disabled'. . At this time, in the case of a secondary serving cell that has been reconfigured or has not changed through the RRC reconfiguration message, the activation or deactivation state remains unchanged.

However, if the UE receives the RRC reconfiguration message including the MCI, that is, in case of handover, all secondary serving cells transition to the 'disabled' state.

12 is a view showing the structure of a MAC PDU, FIG. 13 is a view showing the structure of a MAC subheader, and FIG. 14 is a view showing the structure of a MAC CE. Hereinafter, the structure of the MAC CE will be described in more detail with reference to FIGS. 12 to 14.

Referring first to FIG. 12, a structure of a MAC PDU used when transmitting a downlink shared channel (DL-SCH) and an uplink shared channel (UL-SCH) is illustrated. The MAC PDU is composed of one MAC header, zero or more MAC CEs, zero or more MAC Service Data Units (SDUs), and padding, as shown in FIG. 12. Here, the MAC header and the MAC SDU have a variable length, and padding may be optionally included in the MAC PDU.

The MAC header consists of one or more subheaders. Each subheader corresponds to MAC SDU or MAC CE or padding of the MAC PDU, respectively. That is, the sub-headers of the MAC PDU have the same order as the corresponding MAC SDU, MAC CE, and padding, respectively.

MAC CE for activation / deactivation of a serving cell corresponds to a subheader of a type (R / R / E / LCID type) as shown in FIG. 13. In FIG. 13, 'R' is a bit that is not used as a reserved bit, and 'E' is a bit indicating whether there are additional 8 bits in the corresponding subheader. In addition, 'LCID' represents a logical meaning for MAC CE or MAC SDU corresponding to the corresponding subheader.

For example, the LCID value for the downlink shared channel may be defined as shown in Table 1 below.

Index LCID values 00000 CCCH 00001-01010 Identity of the logical channel 01011-11010 Reserved 11011 Activation / Deactivation 11100 UE Contention Resolution Identity 11101 Timing Advance Command 11110 DRX Command 11111 Padding

Referring to Table 1, the LCID value for MAC CE for activation / deactivation of a serving cell is set to '11011'. Accordingly, the MAC CE corresponding to the subheader of the MAC PDU whose LCID value is set to '11011' is interpreted as shown in FIG. 14.

14 is a structure of MAC CE having a fixed length of 8 bits. In FIG. 14, C ₁ is an indicator indicating activation / deactivation of secondary serving cells having the index value '1' when a secondary serving cell having the index value '1' is configured. Similarly, C ₂ is an indicator indicating activation / deactivation of secondary serving cells having the index value '2' when a secondary serving cell having the index value '2' is configured. At this time, the terminal may ignore the field for the secondary serving cell that is not configured in the terminal (ignore). 'R' is a reserved bit and is always set to '0'.

15A is a diagram illustrating a method of transmitting activation / deactivation information for secondary serving cells according to an embodiment of the present invention.

When a dual connection is configured through a master base station and a secondary base station in the terminal, the terminal may receive an activation / deactivation MAC CE message from each base station through a primary serving cell or a secondary serving cell provided by each base station. Hereinafter, the activation / deactivation MAC CE message received from the master base station is referred to as a first activation / deactivation MAC CE message, and the activation / deactivation MAC CE message received from the secondary base station is referred to as a second activation / deactivation MAC CE message.

In this case, the terminal recognizes and applies only information about the activation / deactivation indicators for the secondary serving cells provided by the master base station in the first activation / deactivation MAC CE message, as shown in FIG. 15A, and applies it to the secondary base station. Information on the activation / deactivation indicators for the secondary serving cells provided by should be ignored. Likewise, for the second activation / deactivation MAC CE message, only the information on the activation / deactivation indicator for the secondary serving cells provided by the secondary base station is recognized and applied, and the activation on the secondary serving cells provided by the master base station / Information about the deactivation indicator should be ignored. In order to selectively apply and ignore the activation / deactivation indicators for the secondary serving cells included in the activation / deactivation MAC CE message as described above, which base station is the secondary serving cell provided by the secondary serving cells configured in the terminal. Must be able to judge.

For this, as an example, the terminal may use a time alignment group (TAG: Timing Advance Group). The TAG is a group including serving cell (s) using the same time advance value and the same timing reference or the timing reference cell including the timing reference among the serving cells configured with the uplink. For example, when the first serving cell and the second serving cell belong to TAG1 and the second serving cell is a timing reference cell, the same time advance value TA1 is applied to the first serving cell and the second serving cell, and the first serving cell Applies the TA1 value based on the downlink synchronization time of the DL CC of the second serving cell. On the other hand, if the first serving cell and the second serving cell belong to TAG1 and TAG2, respectively, the first serving cell and the second serving cell become timing reference cells in the corresponding TAG, respectively, and the first serving cell and the second serving cell have different times. Advance values TA1 and TA2 are applied respectively. The TAG may include a primary serving cell, may include at least one secondary serving cell, or may include a primary serving cell and at least one secondary serving cell. Since serving cells are classified in TAG units, serving cells in different TAGs are provided by different base stations.

On the other hand, TAG is divided into a primary time alignment group (pTAG: primary Timing Advance Group) and a secondary time alignment group (sTAG: secondary Timing Advance Group). pTAG is a TAG including a main serving cell, and sTAG is a TAG composed of only secondary serving cells. Accordingly, the UE can recognize the secondary serving cells included in the pTAG as secondary serving cells provided by the master base station, and the secondary serving cells included in the sTAG as secondary serving cells provided by the secondary base station.

However, among sTAGs, there is also an sTAG composed of secondary serving cells provided by a master base station. Therefore, the terminal receives information on the sTAG composed of the secondary serving cells provided by the master base station from the master base station, and by using this, which sTAG is the sTAG composed of secondary serving cells provided by the master base station. It is possible to distinguish which sTAG is an sTAG composed of secondary serving cells provided by the secondary base station. Information about sTAG composed of secondary serving cells provided by the master base station may be transmitted through an RRC message. In order to transmit the RRC message, the RRC layer in the network or master base station may perform an RRC reconfiguration procedure.

As described above, since the UE can determine which of the secondary serving cells configured in the UE is the secondary serving cell provided by the UE by using the TAG, the MAC CE is activated / deactivated respectively from the master base station and the secondary base station by dual connectivity. Even if a message is received, the activation / deactivation indicators for the secondary serving cells included in each activation / deactivation MAC CE message can be selectively applied and ignored.

Specifically, as shown in FIG. 15A, the master base station provides secondary serving cells having an index value of '1' and secondary secondary cells having index values of '3', '4' and '6' by the secondary base station, respectively. If provided, the terminal uses the information on the sTAG composed of the secondary serving cells provided by the master base station when the first activation / deactivation MAC CE message is received, the index value in the first activation / deactivation MAC CE message ' Only the information on the activation / deactivation indicator for the secondary serving cell with 1 'is recognized, and the information on the activation / deactivation indicator for the secondary serving cells with index values' 3', '4' and '6' can be ignored. have. Likewise, when the second activation / deactivation MAC CE message is received, the terminal indexes the index value in the second activation / deactivation MAC CE message based on information on sTAG composed of secondary serving cells provided by the master base station. Only the information on the activation / deactivation indicator for the secondary serving cells having 3 ',' 4 'and' 6 'is recognized, and the information on the activation / deactivation indicator for the secondary serving cell having an index value of' 1 'is ignored. You can.

On the other hand, the base station may inform the terminal of information about which secondary serving cell is provided by which base station through an RRC message. In this case, the RRC message may include information on a base station that provides a corresponding secondary serving cell for each secondary serving cell configured in the terminal. In this case, since the primary serving cell is provided by the master base station, the RRC message may not include information about the base station providing the primary serving cell. Therefore, even if a terminal receives a plurality of activation / deactivation MAC CE messages, each of the secondary serving cells configured in the terminal can recognize which secondary serving cell is provided by the base station based on the information included in the RRC message. The activation / deactivation indicators for the secondary serving cells included in the activation / deactivation MAC CE message can be selectively applied and ignored.

As shown in Figure 15b, where the PUCCH configured secondary serving cell (also called a special secondary serving cell) has the same activation / deactivation characteristics as the primary serving cell, the activation / deactivation of the secondary serving cell configured with the PUCCH included in the MAC CE message The bit indicating whether to activate / deactivate can be ignored by the terminal.

On the other hand, the index of the serving cells provided to the terminal by the double-connected base stations can be allocated independently of each other. For example, the index of the primary serving cell provided by the master base station may have a value of '0', and the index of the secondary serving cell may have a value of '1' to '7'. Meanwhile, the index of the secondary serving cell provided by the secondary base station and configured with PUCCH is '0', and the index of the secondary serving cell without PUCCH is configured to have a value of '1' to '7'. In this way, when an independent serving cell index is allocated in each base station, the format of the activation / deactivation message and the method for the terminal to receive and apply the activation / deactivation message are as follows.

As shown in FIG. 15C, the UE recognizes and applies information about the activation / deactivation indicators for secondary serving cells provided through the first activation / deactivation MAC CE message as before. Likewise, the terminal recognizes and applies the information on the activation / deactivation indicator for the secondary serving cells provided through the second activation / deactivation MAC CE message as before.

In addition, the rightmost bit, which is a bit provided by a secondary base station and indicates an index of a secondary serving cell configured with PUCCH, is defined as a reserved bit, and the secondary base station cannot deactivate the secondary serving cell configured with the PUCCH. In addition, the secondary serving cell configured with the PUCCH has the same activation / deactivation characteristics and may be defined with the same name as the main serving cell in the master base station.

16 is a view showing a method of transmitting activation / deactivation information for secondary serving cells according to another embodiment of the present invention.

When the terminal is double-connected with a plurality of base stations, the terminal may receive an activation / deactivation MAC CE message from the master base station through a primary serving cell or a secondary serving cell provided by the master base station. In this case, when the status of activation / deactivation of secondary serving cells provided by the secondary base station is changed, the MAC scheduler of the secondary base station can inform the master base station of this information as shown in FIG. 16. At this time, the secondary base station transmits activation / deactivation information for the secondary serving cells provided by the secondary base station to the master base station through a MAC CE message, or through the message format determined by the X2 or Xn interface to the secondary base station. Activation / deactivation information for the secondary serving cells provided by the master base station may be transmitted to the master base station.

The master base station may collect information received from the secondary base station together with activation / deactivation information for secondary serving cells provided by the master base station, construct a final MAC CE message, and then transmit the final MAC CE message to the terminal. .

On the other hand, when the master base station intends to transmit an activation / deactivation MAC CE message for secondary serving cells provided by the master base station to the terminal, activation of secondary serving cells provided by the secondary base station double-connected with the terminal is performed. / You can also check whether the deactivation has changed.

In addition, the master base station can recognize the expiration of a deactivation timer for secondary serving cells provided by the secondary base station. For example, the master base station can recognize the expiration time of the deactivation timer for the secondary serving cells provided by the secondary base station by synchronizing the operation of the deactivation timer for secondary serving cells provided by the secondary base station with the terminal. have. Accordingly, if any secondary serving cell provided by the secondary base station transitions to the inactive state due to the expiration of the inactivity timer, the master base station receives activation information for the secondary serving cell without receiving information about it from the secondary base station. It can be set to 0 'to enable the terminal to deactivate the corresponding secondary serving cell.

In addition, when changing the value of the deactivation timer for each of the secondary serving cells provided by the secondary base station, the secondary base station may transmit the changed deactivation timer value to the master base station. That is, secondary serving cells belonging to the secondary base station and the master base station have different deactivation timer values.

Or, the master base station does not define the operation of the deactivation timer for secondary serving cells provided by the secondary base station. That is, the terminal receives one deactivation timer value per terminal through the master base station, and the timer value is applied only to secondary serving cells in the master base station. Therefore, the deactivation timer for secondary serving cells in the secondary base station is not defined or is always fixed to an infinite value. Accordingly, the master base station maintains the activation information for the secondary serving cells in the secondary base station and transmits it to the terminal unless it receives information indicating that the activation / deactivation state for the secondary serving cell in the secondary base station is changed from the secondary base station. You can.

17 is a flowchart illustrating an operation of a terminal receiving activation / deactivation information for secondary serving cells according to an embodiment of the present invention.

If there is a terminal capable of dual connectivity with the secondary base station, the master base station transmits dual connectivity configuration information to the corresponding terminal through an RRC message. When the terminal receives the double connection configuration information through the RRC message, it establishes a double connection with the master base station and the secondary base station base station based on the received double connection configuration information (S1710). In this case, the RRC message may include information on sTAG composed of secondary serving cells provided by the master base station or information on which secondary serving cell is provided by which base station, and the terminal can perform the RRC. Based on the information included in the message, each of the secondary serving cells configured in the terminal can be determined by which base station the secondary serving cell is provided.

When a dual connection is established, the terminal sets an optional application mode for selectively applying activation / deactivation information for secondary serving cells included in the first activation / deactivation MAC CE message and the second activation / deactivation MAC CE message. (S1720).

Subsequently, when the terminal receives the activation / deactivation MAC CE messages from the base stations, respectively, (S1730), based on the information included in the RRC message, the secondary serving cells configured in the terminal determine which secondary serving cells are provided by each base station. Judge. And, accordingly, in the first activation / deactivation MAC CE message, only activation / deactivation information for the secondary serving cell provided by the master base station is selectively applied and the rest is ignored, and in the second activation / deactivation MAC CE message Only the activation / deactivation information for the secondary serving cell provided by the secondary base station is selectively applied and the rest is ignored (S1740).

18 is a flowchart illustrating an operation of a base station transmitting activation / deactivation information for secondary serving cells according to an embodiment of the present invention.

Referring to FIG. 18, when a terminal capable of dual connectivity exists, the base station configures dual connectivity configuration information for the corresponding terminal and transmits it to the corresponding terminal (S1810). Here, the base station may be a master base station. The dual connection configuration information may be transmitted to a terminal through an RRC message, and the RRC message is information about sTAG composed of secondary serving cells provided by a master base station or which secondary serving cell is provided by which base station. It may contain information about.

On the other hand, the base station determines whether to activate / deactivate the secondary serving cells provided by the base station (S1820), and thus configures the activation / deactivation MAC CE indicating activation and deactivation of each of the secondary serving cells ( S1830). Then, a message including the configured activation / deactivation MAC CE is transmitted to the corresponding terminal (S1840).

Thereafter, the terminal receiving the message including the activation / deactivation MAC CE determines, based on the information received through the RRC message, which base station is configured with itself, which base station is provided by each base station, and Accordingly, among the information on the activation / deactivation indicators of the secondary serving cells included in the message, only the information on the secondary serving cell provided by the base station transmitting the message can be selectively applied.

19 is a flowchart illustrating an operation of a master base station transmitting activation / deactivation information for secondary serving cells according to another embodiment of the present invention.

Referring to FIG. 19, when a terminal capable of dual connectivity exists, the master base station configures dual connectivity configuration information for the corresponding terminal and transmits it to the corresponding terminal (S1910).

Thereafter, the master base station determines whether activation / deactivation of secondary serving cells provided by the master base station is performed (S1920), and activates / deactivates information of secondary serving cells provided by the secondary base station from a secondary base station double-connected to the terminal. After receiving (S1930), MAC CE is activated / deactivated based on these (S1940). Then, a message including the configured activation / deactivation MAC CE is transmitted to the corresponding terminal (S1950). Here, the MAC scheduler of the secondary base station may transmit information about activation / deactivation of the secondary serving cells provided by the secondary base station to the master base station. In addition, when the master base station intends to transmit the activation / deactivation MAC CE message for the secondary serving cells provided by the master base station to the terminal, the activation / deactivation of the secondary serving cells provided by the secondary base station is changed. You can also check whether it is.

Meanwhile, activation / deactivation information of secondary serving cells provided by the secondary base station may be transmitted to the master base station in the form of a MAC CE message, or may be transmitted to the master base station in the form of a message determined in the X2 or Xn interface.

In addition, the master base station can recognize the expiration time of the deactivation timer for the secondary serving cells provided by the secondary base station by synchronizing the operation of the deactivation timer for secondary serving cells provided by the secondary base station with the terminal. In this case, if any secondary serving cell provided by the secondary base station transitions to the inactive state due to the expiration of the inactive timer, the master base station receives activation information for the secondary serving cell without receiving information about it from the secondary base station. It can be set to 0 'to enable the terminal to deactivate the corresponding secondary serving cell. On the other hand, if the secondary base station changes the value of the deactivation timer for each of the secondary serving cells provided by the secondary base station, it may transmit the changed deactivation timer value to the master base station.

20 is a flowchart illustrating the operation of a secondary base station transmitting activation / deactivation information for secondary serving cells according to another embodiment of the present invention.

The secondary base station configured with the master base station and the dual connection to the terminal determines whether activation / deactivation of the secondary serving cells provided by the secondary base station is performed (S2010), and accordingly, activation of secondary serving cells provided by the secondary base station / The deactivation information is transmitted to the master base station (S2020). At this time, the MAC scheduler of the secondary base station activates / deactivates the secondary serving cells provided by the secondary base station from the master base station when the activation / deactivation state of the secondary serving cells provided by the secondary base station is changed. When receiving a request to confirm whether to change, the activation / deactivation information of secondary serving cells provided by the secondary base station may be transmitted to the master base station. Here, the activation / deactivation information of secondary serving cells provided by the secondary base station may be transmitted to the master base station in the form of a MAC CE message or a message determined in the X2 or Xn interface.

Meanwhile, the deactivation timer for the secondary serving cells provided by the secondary base station can be operated in synchronization with the terminal so that the master base station can recognize the expiration time of the deactivation timer for the secondary serving cells provided by the secondary base station. The secondary base station may transmit the changed deactivation timer value to the master base station when changing the deactivation timer value for each of the secondary serving cells provided by the secondary base station.

21 is a block diagram showing an example of an activation / deactivation information transmitting and receiving device for secondary serving cells according to the present invention.

The activation / deactivation information transmitting device 2110 for secondary serving cells according to the present invention may be a base station or a part of a base station, and the activation / deactivation information receiving device 2120 for secondary serving cells may be a terminal or a part of a terminal. have. Referring to FIG. 21, the activation / deactivation information transmission device 2110 for secondary serving cells includes a determination unit 2111 and a transmission unit 2112, and an activation / deactivation information reception device for secondary serving cells ( 2120 includes a receiving unit 2121, a determining unit 2122 and an application unit 2123. Hereinafter, an example in which the activation / deactivation information transmitting apparatus 2110 for secondary serving cells is a base station and the activation / deactivation information receiving apparatus 2120 for secondary serving cells is a terminal will be described as an example.

The determination unit 2111 of the base station 2110 determines whether to activate / deactivate the secondary serving cells provided by the base station 2110.

The transmitting unit 2112 configures an activation / deactivation MAC CE indicating activation and deactivation of each of the secondary serving cells according to the determination of the determination unit 2111, and transmits a message including the configured activation / deactivation MAC CE to the terminal ( 2120). In addition, the transmitter 2112 may transmit information on the sTAG composed of the secondary serving cells provided by the master base station or information on the base station providing the secondary serving cell configured on the terminal 2120 to the terminal 2120. .

At this time, if the base station 2110 is a master base station and a dual connection to a secondary base station and a single terminal 2120 is configured, the master base station activates the secondary serving cells provided by the secondary base station from the secondary base station. / Disable information can be received. In this case, the transmission unit 2112 may generate an activation / deactivation MAC CE message based on the determination result of the determination unit 2111 and the information received from the secondary base station, and then transmit it to the terminal 2120. However, if the base station 2110 is a secondary base station and a dual connection is established between the master base station and one terminal 2120, the transmitting unit 2112 serves as the master base station of secondary serving cells provided by the secondary base station. The activation / deactivation information can be transmitted.

The receiving unit 2121 of the terminal 2120 is an activation / deactivation MAC CE message, information about sTAG composed of secondary serving cells provided by the master base station, and information about a base station providing secondary serving cells configured in the terminal 2120. At least one of the can be received from the base station 2110. The receiving unit 2121 may receive information on the sTAG composed of the secondary serving cells provided by the master base station and information on the base station providing the secondary serving cell configured on the terminal 2120 through an RRC message.

The determination unit 2122 receives the information on the sTAG composed of the secondary serving cells provided by the master base station or the base station providing the secondary serving cell configured on the terminal 2120 when the receiving unit 2121 receives the basic information. Each of the secondary serving cells configured in the UE 2120 determines which secondary serving cell is provided by which base station.

According to the determination result of the determination unit 2122, the application unit 2123, among the information on the activation / deactivation indicators of the secondary serving cells included in the activation / deactivation MAC CE message, is provided by the base station that has transmitted the message. Only information about cells is selectively applied.

In the exemplary system described above, the methods are described based on a flow chart as a series of steps or blocks, but the present invention is not limited to the order of steps, and some steps may occur in a different order than the steps described above or simultaneously. You can. In addition, those skilled in the art will understand that the steps shown in the flowcharts are not exclusive, other steps may be included, or one or more steps in the flowchart may be deleted without affecting the scope of the present invention.

The above-described embodiments include examples of various aspects. It is not possible to describe all possible combinations for representing various aspects, but a person skilled in the art will recognize that other combinations are possible. Accordingly, the present invention will be said to include all other replacements, modifications and changes that fall within the scope of the following claims.

Claims (16)

In the method of activating a serving cell by a terminal supporting a dual connection with the first node and the second node in the wireless communication system,
Receiving first information including an activation / deactivation indicator for a secondary serving cell (SCell) of a first secondary serving cell group configured in the terminal from the first node;
Receiving second information including an activation / deactivation indicator for a secondary serving cell (SCell) of a second secondary serving cell group configured in the terminal from the second node;
According to the activation / deactivation indicator for the secondary serving cell of the first secondary serving cell group identified from the first information received from the first node, the status of the secondary serving cell of the first secondary serving cell group is activated or Controlling to be deactivated; And
According to the activation / deactivation indicator for the secondary serving cell of the second secondary serving cell group identified from the second information received from the second node, the status of the secondary serving cell of the second secondary serving cell group is activated or A method of activating / deactivating a serving cell, comprising controlling to be deactivated. According to claim 1,
A method of activating / deactivating a serving cell, further comprising configuring a dual connection by being connected to a radio resource control (RRC) with the first node and the second node. According to claim 1,
The first node is a master evolved NodeB (MeNB) and the second node is a secondary evolved NodeB (SeNB) serving cell activation / deactivation method. According to claim 3,
Activating a serving cell further comprising receiving a radio resource control (RRC) signal including information on a secondary serving cell configuration for a first node and information on a secondary serving cell configuration for a second node from the MeNB. / Disabled method. According to claim 4,
Identifying a secondary serving cell belonging to the first secondary serving cell group associated with the MeNB or a secondary serving cell belonging to the second secondary serving cell group associated with the SeNB using the RRC signal received from the MeNB; A method of activating / deactivating a serving cell further comprising. delete According to claim 1,
The first information includes a medium access control (MAC) control element (CE) having an 8-bit size,
The second information includes MAC CE having an 8-bit size,
The MAC CE received from the first node and the MAC CE received from the second node each have 1 bit reserved and 7 bits configurable, and each bit of the 7 bits configurable is in the index of the secondary serving cell. Correspondence,
One bit for a secondary serving cell having an index i in the MAC CE received from the first node corresponds to an activation / deactivation indicator for the corresponding secondary serving cell in the first node,
One bit for a secondary serving cell having an index j in the MAC CE received from the second node corresponds to an activation / deactivation indicator for the corresponding secondary serving cell in the second node,
The i and j are values in the range of 1 to 7, and a method of activating / deactivating serving cells having different values. The method of claim 7,
Identifying a bit corresponding to a secondary serving cell associated with the first node in the MAC CE received from the first node using a first MAC scheduler; And
And identifying a bit corresponding to the secondary serving cell associated with the second node in the MAC CE received from the second node using a second MAC scheduler. In the method of activating / deactivating a serving cell by a terminal supporting dual connectivity in a wireless communication system,
Receiving a first medium access control (MAC) control element (CE) including an activation / deactivation indicator for a secondary serving cell associated with the MeNB from a master evolved NodeB (MeNB);
Receiving a second MAC CE including an activation / deactivation indicator for a secondary serving cell associated with the SeNB from a secondary evolved NodeB (SeNB);
Identifying an activation / deactivation indicator corresponding to an index of the secondary serving cell associated with the MeNB in the first MAC CE;
Controlling activation / deactivation of the secondary serving cell associated with the MeNB based on the first MAC CE received from the MeNB;
Identifying an activation / deactivation indicator corresponding to an index of the secondary serving cell associated with the SeNB in the second MAC CE; And
And controlling activation / deactivation of the secondary serving cell associated with the SeNB based on the second MAC CE received from the SeNB. The method of claim 9,
A method of activating / deactivating a serving cell, further comprising configuring a radio resource control (RRC) connection with the MeNB and the SeNB for dual connectivity. The method of claim 9,
The method further includes receiving the secondary serving cell configuration information of the MeNB from the MeNB and receiving the secondary serving cell configuration information of the SeNB from the SeNB.
Method for activating / deactivating a serving cell in which the secondary serving cell configuration information of the MeNB and the secondary serving cell configuration information of the SeNB are transmitted through a Radio Resource Control (RRC) message from the MeNB. delete The method of claim 9,
Identifying a secondary serving cell configured for the MeNB using the MAC scheduler of the MeNB; And
A method of activating / deactivating a serving cell, further comprising identifying a secondary serving cell configured for the SeNB using the MAC scheduler of the SeNB. The method of claim 9,
The MAC CE received from the MeNB and the MAC CE received from the SeNB are each 8 bits in size including 1 bit reserved and 7 bits configurable,
Each bit of the configurable 7 bits corresponds to the index of the secondary serving cell,
A method of activating / deactivating a serving cell in which a secondary serving cell index i corresponding to a secondary serving cell associated with the MeNB and a secondary serving cell index j corresponding to a secondary serving cell associated with the SeNB are different integers. The method of claim 9,
The secondary serving cell associated with the MeNB is included in a first serving cell group (SCG), and the secondary serving cell associated with the SeNB is included in a second serving cell group (SCG). The method of claim 14,
A configurable bit included in the MAC CE received from the MeNB and corresponding to the index i of the secondary serving cell indicates an activation / deactivation indicator for the secondary serving cell having an index i,
A configurable bit included in the MAC CE received from the SeNB and corresponding to the index j of the secondary serving cell indicates an activation / deactivation indicator for the secondary serving cell having the index j,
One configurable bit included in the MAC CE received from the SeNB and corresponding to the secondary serving cell index i is ignored, and one included in the MAC CE received from the MeNB and corresponding to the secondary serving cell index j The configurable bit of the activation / deactivation method of the serving cell is ignored.

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