KR101556494B1 - Apparatus and Method for Adaptive Carrier Aggregation in LTE System - Google Patents

Abstract

The present invention relates to an apparatus and a method for adaptive carrier aggregation (CA) in an LTE system wherein a CA operation coverage can be widened while delay of CA operation initiation time is minimized. The method for adaptive CA in an LTE system according to an aspect of the present invention is performed in a UE and includes the steps of: receiving a first message including predetermined Scell add command information and Scell hand over (HO) condition information from eNB after completion of setting up radio resource control (RRC) between the eNB and the UE; (b) adding a relevant Scell based on the predetermined Scell add command information of the received first message; (c) transmitting a second message, including Scell HO request information, to the eNB based on the Scell HO condition information of the received first message after adding the Scell in step (b); receiving a third message, including Scell HO command information, from the eNB based on the Scell HO request information of the second message; and performing HO to a relevant Scell based on the Scell HO command information of the received third message.

Description

[0001] Apparatus and Method for Adaptive Carrier Aggregation in LTE System [

The present invention relates to an apparatus and method for adaptive Carrier Aggregation (hereinafter abbreviated as CA) in an LTE system.

In general, the LTE system is a mobile communication system evolved in the UMTS system, and a standard has been established in the 3GPP (3GPP 3GPP) as an international standardization organization, and its schematic system structure is as shown in FIG.

1 is a diagram for explaining a structure of an LTE system.

The LTE system structure can be broadly classified into Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) and Evolved Packet Core (EPC). The E-UTRAN is composed of a UE (User Equipment) and an eNB (Evolved NodeB, base station). The UE-eNB is called a Uu interface and the Enb-eNB is called an X2 interface. The EPC is composed of an MME (Mobility Management Entity) for performing a control plane function and an S-GW (Serving Gateway) for performing a user plane function. Interface, and the eNB-S-GW are referred to as S1-U interfaces, which are collectively referred to as S1 interfaces.

A radio interface protocol is defined in the Uu interface, which is a wireless section, and is horizontally composed of a physical layer, a data link layer, and a network layer, A user plane (U-plane) for transmitting user data and a control plane (C-plane) for transmitting a control signal (Signaling). Such a wireless interface protocol is generally classified into an L1 (first layer) including a physical layer PHY, a MAC / MAC layer including a PHY based on the lower three layers of an Open System Interconnection (OSI) An L2 (second layer) including an RLC / PDCP layer, and an L3 (third layer) including an RRC layer. They exist in pairs in the UE and the E-UTRAN, and are responsible for data transmission of the Uu interface.

The LTE-A system will be described below.

Long Term Evolution Advanced (LTE-A) system is suitable for IMT-Advanced condition of 4th generation mobile communication recommendation of LTE system in ITU-R (International Telecommunication Union - Radiocommunication sector) And developed the LTE-A system standard in 3GPP, which developed the LTE system standard.

Representative technologies newly added to the LTE-A system include Carrier Aggregation technology, which can expand the usable bandwidth and can be used flexibly, and improve the coverage and the group mobility. And a repeater technology that enables user-centric network deployment.

FIG. 2 and FIG. 3 are views for explaining each layer of a wireless protocol.

The physical layer (PHY) layer of the first layer provides an information transfer service to an upper layer using a physical channel. The PHY layer is connected to an upper layer of Medium Access Control (MAC) layer through a transport channel, and data is transferred between the MAC layer and the PHY layer through the transport channel. At this time, the transmission channel is largely divided into a dedicated transmission channel and a common transmission channel depending on whether the channel is shared or not. Data is transferred between different PHY layers, that is, between a PHY layer of a transmitter and a PHY layer of a receiver through a physical channel using radio resources.

There are several layers in the second layer. First, the Medium Access Control (MAC) layer maps various logical channels to various transport channels, and also performs logical channel multiplexing in which a plurality of logical channels are mapped to one transport channel Role. The MAC layer is connected to an RLC layer, which is an upper layer, through a logical channel. A logical channel includes a control channel for transmitting control plane information according to the type of information to be transmitted, And a traffic channel for transmitting information of a user plane (User Plane).

The Radio Link Control (RLC) layer of the second layer divides and concatenates the data received from the upper layer to adjust the data size so that the lower layer is suitable for transmitting data in the radio section . In order to guarantee various QoSs required by the respective radio bearers (RBs), a TM (Transparent Mode), a UM (Un-acknowledged Mode), and an AM (Acknowledged Mode) And a response mode). In particular, the AM RLC performs a retransmission function through an automatic repeat and request (ARQ) function for reliable data transmission.

The Packet Data Convergence Protocol (PDCP) layer of the second layer is an IP (Packet Data Convergence Protocol) layer that is relatively large and contains unnecessary control information in order to efficiently transmit IP packets, such as IPv4 or IPv6, It performs header compression to reduce packet header size. This makes it possible to transmit only necessary information in the header portion of the data, thereby increasing the transmission efficiency of the radio section. In the LTE system, the PDCP layer also performs a security function, which consists of ciphering to prevent third party data interception and integrity protection to prevent third party data manipulation.

A radio resource control (RRC) layer located at the uppermost layer of the third layer is defined only in the control plane and includes a configuration, a re-configuration and a release of radio bearers (RBs) And is responsible for controlling logical channels, transport channels, and physical channels. The RB means a logical path provided by the first and second layers of the wireless protocol for data transmission between the terminal and the UTRAN. Generally, the RB is set to indicate a wireless protocol layer and a channel Quot; means specifying a characteristic, and setting each concrete parameter and an operation method. RB is divided into SRB (Signaling RB) and DRB (Data RB). SRB is used as a channel for transmitting RRC messages on the C-plane, and DRB is used as a channel for transmitting user data on the U-plane .

Hereinafter, the RRC_IDLE state of the terminal will be described in detail. A terminal in the RRC idle state (RRC_IDLE) must always select an appropriate quality cell and prepare for receiving service through this cell. For example, a powered down terminal must select a cell of the appropriate quality to register with the network. When the UE in the RRC_CONNECTED state enters the RRC_IDLE, the UE must select a cell in the RRC_IDLE. In this manner, a process of selecting a cell satisfying a certain condition in order to stay in a service waiting state such as the RRC_IDLE state is referred to as a cell selection.

Hereinafter, a method of selecting a cell by a terminal will be described in detail. When the terminal is initially powered on, the terminal searches for an available PLMN and selects the appropriate PLMN to receive the service. Then, among the cells provided by the selected PLMN, a cell having a signal quality and characteristics such that the UE can receive an appropriate service is selected. Here, the cell selection process is roughly divided into two. First, an initial cell selection process is performed. In this process, the UE does not have prior information on a wireless channel. Therefore, the terminal searches all wireless channels to find an appropriate cell. In each channel, the terminal finds the strongest cell. Thereafter, when the terminal finds a suitable cell satisfying the cell selection criterion, it selects the corresponding cell.

The following is a cell selection process that utilizes stored information. In this process, information stored in the terminal for a wireless channel is utilized, or cell selection is performed using information broadcast in the cell. Therefore, the cell selection can be faster than the initial cell selection process. When the terminal finds a cell satisfying the cell selection criterion, it selects the corresponding cell. If the UE does not find a suitable cell satisfying the cell selection criterion, the UE performs an initial cell selection process.

Hereinafter, a method of reselecting a cell by a terminal will be described in detail. Once the cell is selected through the cell selection process, the strength or quality of the signal between the UE and the BS may change due to mobility of the UE or change of the radio environment. Thus, if the quality of the selected cell degrades, the terminal may select another cell that provides better quality. When the cell is reselected in this way, a cell is selected that generally provides better signal quality than the currently selected cell. This process is called cell reselection. The cell reselection process is basically aimed at selecting a cell that provides the best quality to the UE in terms of the quality of the radio signal. In addition to the quality of the radio signal, the network can determine the priority for each frequency and inform the terminal of the priority. The MS receiving the priority order takes priority over the radio signal quality reference in the cell reselection process.

Hereinafter, Carrier Aggregation (abbreviated as CA) of the LTE-A system will be described.

4 is a diagram for explaining the CA technique.

As described above, the LTE-A technology standard is an IMT-Advanced candidate technology of the International Telecommunication Union (ITU), and is designed to meet the ITU-IMT-Advanced technology requirements. Accordingly, in order to meet the requirements of ITU, the LTE-A is in the process of expanding the bandwidth compared to the existing LTE system. In order to extend the bandwidth in the LTE-A system, a carrier that can be present in the existing LTE system is defined as a constituent carrier (hereinafter referred to as CC), and this CC is divided into a maximum of 5 It is discussed that it can be bundled up. Since CC can have bandwidths of up to 20 MHz, as in LTE systems, CA technology in the LTE-A technology standard is a concept that can extend bandwidth up to 100 MHz, for example. The technique of using multiple CCs in this way is called CA.

In general, the CA technology is implemented using the Blind 1: 1 CA scheme of FIG. 5 and the Freq. Search 1: The NCA method is implemented in two major ways.

As shown in FIG. 5, the conventional Blind 1: 1 CA scheme is a method in which a cell is configured to be unconditionally CA by two cells designated by the operator in advance, that is, Cell C and Cell A, C and Cell A), it is possible to add a fast secondary cell (Cell A) to the Pcell (Primary Cell: Cell C) at the same time as the bearer setup, There is a disadvantage in that CA operation can not be performed in the coverage (b) area, and CA coverage is small because of this.

Existing Freq. 6, CA configuration of various configurations (AC or BC) is possible by configuring CA with 1: N without operator setting, and CA coverage (a) or b) CA coverage can expand. However, since a cell does not know how to configure it as a Scell, an add operation is required after a Scell search through InterFreq Search of the terminal, and an additional time (about 2 seconds) And the CA operation start time is delayed.

Korean Patent Laid-Open No. 10-2012-0019440 (published on Mar. 6, 2012)

SUMMARY OF THE INVENTION It is an object of the present invention to provide an adaptive CA for adaptive carrier aggregation (CA) in an LTE system, which can broaden the CA operation coverage while minimizing the delay of the CA operation start time. And a method thereof.

According to an aspect of the present invention, there is provided an apparatus for adaptive CA (Adaptive CA) in an LTE system, the apparatus for adaptive CA included in an eNB, A first CA unit for transmitting a first message including Scell Join command information and Scheduled Handover (HO) condition information preset to the UE upon completion of RRC (Radio Resource Control) setup between UEs; ; And transmitting a third message including Scell HO command information to the UE based on the Scell HO request information when a second message including Scell HO request information is received from the UE based on the Scell HO condition information, The first message may comprise a second CA for RRC Conn. Reconfiguration message, the second message is a Measurement Report message, and the third message is a RRC Conn. Reconfiguration message may be included.

According to another aspect of the present invention, there is provided an apparatus for Adaptive CA in an LTE system, the apparatus for Adaptive CA included in a UE, When a radio resource control (RRC) setup between UEs is completed and a first message including Scell Join command information and Scheduled Handover (HO) condition information is received from the eNB, A first CA unit for performing a combination with a corresponding Scell based on Scell Join command information; And transmitting the second message including the Scell HO request information to the eNB based on the Scell HO condition information after performing the combining with the corresponding Scell, And a second CA unit for performing a handover to the corresponding Scell based on the Scell HO command information of the received third message when the third message including the command information is received, Conn. Reconfiguration message, the second message is a Measurement Report message, and the third message is a RRC Conn. Reconfiguration message may be included.

According to another aspect of the present invention, there is provided a method for adaptive CA (Adaptive CA) in an eNB, the method comprising: a) transmitting a first message including Scill Join command information and Scheduled Handover (HO) condition information to the UE upon completion of RRC (Radio Resource Control) setup between the eNB and the UE; ; (b) receiving, from the UE, a second message including Scell HO request information based on Scell HO condition information of the first message; And (c) transmitting a third message including Scell HO command information to the UE based on the Scell HO request information of the received second message, wherein the first message is transmitted to the RRC Conn. Reconfiguration message, the second message is a Measurement Report message, and the third message is a RRC Conn. Reconfiguration messages can be used.

According to another aspect of the present invention, there is provided a method for adaptive CA in an LTE system, the method comprising the steps of: a) receiving a first message including Scell Join command information and Scell Handover (HO) condition information preset from the eNB upon completion of RRC (Radio Resource Control) setup between the eNB and the UE; ; (b) performing a combination with a corresponding Scell based on predetermined Scell Join command information of the received first message; (c) transmitting, to the eNB, a second message including Scell HO request information based on the Scell HO condition information of the received first message after performing the combining with the corresponding Scell in the step (b) ; (d) receiving from the eNB a third message including Scell HO command information based on Scell HO request information of the second message; And (e) performing a handover to a corresponding Scell based on the Scell HO command information of the received third message, wherein the first message is a RRC Conn. Reconfiguration message, the second message is a Measurement Report message, and the third message is a RRC Conn. Reconfiguration messages can be used.

According to another aspect of the present invention, there is provided a computer-readable recording medium recording a program for causing a computer to perform a method for adaptive carrier aggregation (Adaptive CA) in the LTE system .

According to another aspect of the present invention, an application stored in a medium may be provided to combine and execute a method for adaptive CA in the LTE system.

According to another aspect of the present invention, there is provided a computer program stored in a medium for causing a computer to execute a method for adaptive carrier aggregation in the LTE system.

As described above, according to various aspects of the present invention, when a call set is unconditionally CA configured with a scaled set of paired cells at the time of call setup, the eNB transmits HO condition information (A6 HO Measurement Report condition information) By allowing the UE to continue to look for a better signal scell after the CA configuration and to allow the UE to immediately go through the Scell (based on the A6 Mesurement Report) when it finds a better signal scell, Operates as a 1: N CA with a preconfigured 1: 1 CA to minimize the Scell Add delay (for 2 seconds due to Inter-Freq Search, which is the maximum disadvantage of 1: N CA) The CA operation coverage can be enlarged.

1 is a diagram for explaining a structure of an LTE system,
2 and 3 are views for explaining each layer of a wireless protocol,
4 is a diagram for explaining a CA (Carrier Aggregation) technique,
5 and 6 are diagrams for explaining a method of operating the existing CA technology,
FIG. 7 is a block diagram of a system for Adaptive Carrier Adaptation (CA) in an LTE system according to an embodiment of the present invention;
8 is a configuration diagram of an apparatus for adaptive CA (Adaptive CA) included in an eNB according to an embodiment of the present invention.
9 is a configuration diagram of an apparatus for Adaptive Carrier Acceptance (CA) included in a UE according to an embodiment of the present invention;
10 is a flow chart of a method for adaptive CA (Adaptive CA) in an LTE system according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals are used to denote like elements in the drawings, even if they are shown in different drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

7 is a block diagram of a system for adaptive CA in the LTE system according to an embodiment of the present invention. As shown in the figure, the MME 7, the eNB 8, and the UE 9).

The MME (Mobile Management Entity) 7 represents a mobility management entity provided in the EPC (Evolved Packet Core).

 the eNode B 8 transmits a radio communication with the UE 9 to an EUTRAN (Evolved Universal Terrestrial Radio Access Network) for data service based on multiple PDN (Packet Data Network) in an LTE (Long Term Evolution) And a base station apparatus for relaying.

The user equipment (UE) 9 represents a mobile terminal such as a smart phone, a notepad, a tablet PC or the like as a user's mobile terminal device, And may include various mobile terminals capable of receiving data (packet) services over the wireless Internet.

The UE 9 can receive the data call transmission through the wireless communication relay of the eNB 8 of the LTE network to the MME 7 as an exchange means and can receive the data call through the interworking with the HSS (Home Subscriber Server) GW (Serving Gateway) (not shown) and P-GW (not shown) are connected to the call origination in accordance with the exchange function of the MME 7 performing authentication, paging, session management, mobility management, routing, (PDN Gateway) (not shown) and establishes a bearer with the eNB 8 so that data transmission / reception with the destination node via the Internet is performed.

8 is a block diagram of an apparatus for adaptive CA (Adaptive CA) included in the eNB 8 of FIG. 7 according to an embodiment of the present invention. As shown in the figure, the first CA unit 81, And a second CA portion 82. The first and second CA portions 82,

When the radio resource control (RRC) setup between the eNB 8 and the UE 9 is completed, the first CA (Carrier Aggregation) unit 81 transmits predetermined Scill Join command information and Scell Handover (Hand Over) RRC Conn as the first message containing the HO condition information. Reconfiguration to be transmitted to the UE 9, for example, from the UE 9 to the RRC Conn. Scheduling command information for instructing to add a predetermined Scell when the Setup Complete message is received and an Initial Context Setup Request message from the MME 7 is received and a Scell HO The condition information is transmitted to the RRC Conn. Reconfiguration message to UE (9).

The second CA (Carrier Aggregation) unit 82 receives the Measurement Report message as the second message including the Scell HO request information based on the Scell HO condition information from the UE 9, and transmits the received Scell HO request information RRC Conn as a third message containing Scell HO command information as a basis. For example, RRC Conn. ≪ / RTI > as a first message from the UE 9, for example. In response to the reconfiguration message, the RRC Conn. After receiving a Reconfiguration Complete message, if a Measurement Report message is received as a second message including Scell HO request information based on the Scell HO condition information from the UE 9, RRC Conn as a third message containing Scell HO command information. To generate and transmit a reconfiguration message to the UE 9.

In this embodiment, the Scell HO condition information may include reference information (for example, 3 dB or more) about the intensity of a predetermined reception signal (reception signal from the surrounding Cell), and the Scell HO request information may satisfy the Scell HO condition It can contain one Scell information.

9 is a block diagram of an apparatus for adaptive carrier aggregation (Adaptive CA) included in the UE 9 of FIG. 7 according to an embodiment of the present invention. As shown in the figure, a first CA unit 91, And a second CA portion 92. As shown in FIG.

The first CA unit 91 is for configuring a CA by selecting a predetermined paired cell at the time of call set up. For example, when the RRC (Radio Resource Control) setup between the eNB 8 and the UE 9 is completed RRC Conn as a first message including Scell Join command information and Scheduled Handover (HO) condition information preset from the eNB 8. When a reconfiguration message is received, the received RRC Conn. And performs a combination with the corresponding Scell based on the previously set Scell Join command information of the Reconfiguration message.

The second CA unit 92 performs a handover process for continuously searching for a Scell of a better signal after the UE 9 performs a connection with a predetermined Scell (Paired Cell) through the first CA unit 91 For example, the received RRC Conn. Based on the Scell HO condition information of the reconfiguration message, scell matching the HO condition is continuously searched and the Scell HO request information including the searched Scell information is loaded into the Measurement Report message as the second message and transmitted to the eNB (8) , And then transmits RRC Conn. RN as a third message including Scell HO command information based on the Scell HO request information from the eNB (8). When the reconfiguration message is received, the RRC Conn. And handover to the corresponding Scell based on the Scell HO Command information of the Reconfiguration message.

FIG. 10 is a flowchart of a method for adaptive CA (Adaptive CA) in an LTE system according to an embodiment of the present invention. FIG. 10 is applied to the apparatuses of FIGS.

First, the UE 9 transmits the RRC Conn. (S101), the eNB 8 transmits the RRC Conn. In response to the Request message, the RRC Conn. (S102), and the UE 9 transmits the setup message to the RRC Conn. In response to the Setup message, the RRC Conn. And transmits the Setup Complete message to the eNB 8 (S103).

When the RRC setup between the UE 9 and the eNB 8 is completed by performing the above-described steps S101 to S103, the eNB 8 sends an Initial UE message to the MME 7 for bearer formation (S104) 7 generates an Initial Context Setup Request message in response to the Initial UE message received in step S104 and sends it to the eNB 8 (S105).

When the eNB 8 receives the Initial Context Setup Request message from the MME 7 in step S105, the eNB 8 determines whether the RRC Conn. In response to the Setup Complete message, the Scell HO condition information including the Scell combining command information and the predetermined receiving signal strength (3 dB) information for instructing to add a predetermined Paired Scell to the RRC Conn. And sends it to the UE 9 (S106).

The UE 9 then compares the RRC Conn. Performs combining with a paired schedules based on the Scell combining command information in the reconfiguration message, and adds the RRC Conn. In response to the reconfiguration message, the RRC Conn. The eNB 8 generates a Reconfiguration Complete message and sends it to the eNB 8 in step S107. When the Reconfiguration Complete message is received from the UE 9, the Initial Context Setup Complete message is generated in response to the Initial Context Setup Request message received in step S105 and sent to the MME 7 in step S108.

Subsequently, the UE 9 determines whether the RRC Conn. Based on the Scell HO condition information in the reconfiguration message, the Scell is continuously searched according to the handover condition. If the Scell is found, the Scell HO request information including the discovered Scell information is loaded in the Measurement Report message and transmitted to the eNB 8 (S109).

Finally, based on the Scell HO request information of the Measurement Report message received in step S109, the eNB 8 transmits RRC Conn. And transmits the reconfiguration message to the UE 9, and the UE 9 transmits the RRC Conn. The handover to the corresponding Scell is performed based on the Scell HO command information of the reconfiguration message (S110).

Meanwhile, even when the Pcell performs handover (HO), as described above, a predetermined CA is unconditionally set as a paired cell, and then handover is performed by continuously searching for a better signal Scell.

As described above, a method for adaptive CA in an LTE system according to an embodiment of the present invention includes a computer-readable recording medium (or application program) including program instructions for performing various computer- ). ≪ / RTI > The computer-readable recording medium may include a program command, a local data file, a local data structure, or the like, alone or in combination. The recording medium may be those specially designed and constructed for the embodiments of the present invention or may be those known to those skilled in the computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape, optical recording media such as CD-ROMs and DVDs, magneto-optical media such as floppy disks, and ROMs, And hardware devices specifically configured to store and execute the same program instructions. The recording medium may be a transmission medium such as an optical or metal line, a wave guide, or the like, including a carrier wave for transmitting a signal designating a program command, a local data structure, or the like. Examples of program instructions may include machine language code such as those generated by a compiler, as well as high-level language code that may be executed by a computer using an interpreter or the like.

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.

7: MME (Mobile Management Entity)
8: eNB (eNode B)
81: First CA section
82: 2nd CA part
9: UE (User Equipment)
91: First CA section
92: 2nd CA part

Claims (11)

An apparatus for an adaptive carrier aggregation (Adaptive CA) included in an eNB,
a first message for transmitting a first message including Scell Join command information and Scell Handover (HO) condition information preset to the UE upon completion of RRC (Radio Resource Control) setup between the eNB and the UE; CA portion; And
When a second message including Scell HO request information is received from the UE based on the Scell HO condition information, transmitting a third message including Scell HO command information to the UE based on the Scell HO request information A second CA portion;
(Adaptive CA) in an LTE system. The method according to claim 1,
The first message is transmitted to the RRC Conn. Reconfiguration message, the second message is a Measurement Report message, and the third message is a RRC Conn. Wherein the reconfiguration message is a reconfiguration message for the adaptive carrier aggregation in the LTE system. An apparatus for Adaptive CA included in a UE,
when a radio resource control (RRC) setup between the eNB and the UE is completed and a first message including Scell Join command information and Scheduled Handover (HO) condition information is received from the eNB, A first CA unit for performing a combination with a corresponding Scell based on predetermined Scell Join command information; And
And transmitting a second message including Scell HO request information to the eNB based on the Scell HO condition information after performing the combining with the corresponding Scell, A second CA unit for performing a handover to a corresponding Scell based on Scell HO command information of the received third message when a third message including information is received;
(Adaptive CA) in an LTE system. The method of claim 3,
The first message is transmitted to the RRC Conn. Reconfiguration message, the second message is a Measurement Report message, and the third message is a RRC Conn. Wherein the reconfiguration message is a reconfiguration message for the adaptive carrier aggregation in the LTE system. A method for adaptive CA that is performed in an eNB,
(a) Upon completion of RRC (Radio Resource Control) setup between the eNB and the UE, the UE transmits a first message including Scell Join command information and Scheduled Handover (HO) condition information to the UE step;
(b) receiving, from the UE, a second message including Scell HO request information based on Scell HO condition information of the first message; And
(c) transmitting a third message including Scell HO command information to the UE based on Scell HO request information of the received second message;
A method for adaptive carrier aggregation (CA) in an LTE system. 6. The method of claim 5,
The first message is transmitted to the RRC Conn. Reconfiguration message, the second message is a Measurement Report message, and the third message is a RRC Conn. And a reconfiguration message for the adaptive carrier aggregation in the LTE system. A method for adaptive CA, performed by a UE,
(a) Upon completion of RRC (Radio Resource Control) setup between the eNB and the UE, receiving a first message including Scell Join command information and Scell Handover (HO) condition information set in advance from the eNB step;
(b) performing a combination with a corresponding Scell based on predetermined Scell Join command information of the received first message;
(c) transmitting, to the eNB, a second message including Scell HO request information based on the Scell HO condition information of the received first message after performing the combining with the corresponding Scell in the step (b) ;
(d) receiving from the eNB a third message including Scell HO command information based on Scell HO request information of the second message; And
(e) performing a handover to a corresponding Scell based on Scell HO command information of the received third message;
A method for adaptive carrier aggregation (CA) in an LTE system. 8. The method of claim 7,
The first message is transmitted to the RRC Conn. Reconfiguration message, the second message is a Measurement Report message, and the third message is a RRC Conn. And a reconfiguration message for the adaptive carrier aggregation in the LTE system. A computer-readable recording medium having recorded thereon a program for causing a computer to execute a method for adaptive carrier aggregation (Adaptive CA) in the LTE system according to any one of claims 5 to 8. An application stored on a medium for implementing the method for adaptive carrier aggregation (Adaptive CA) in the LTE system according to any one of claims 5 to 8 in combination with hardware. A computer program stored on a medium for executing in a computer a method for adaptive CA in the LTE system as claimed in any one of claims 5 to 8.

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