KR20160079241A - Method for setting connection between user equipment and base station in communication system supporting carrier aggregation - Google Patents

Abstract

Disclosed is a connection setting method which includes a step of setting the RRC connection of a base station, a step of receiving an RRC connection resetting message from the base station, wherein the RRC connection resetting message indicates that a predetermined blind SCell is added to a terminal when the blind SCell is preset in the base station, and a step of adding connection with the blind SCell without measurement for the blind SCell according to the reception of the RRC connection resetting message. So, efficiency in a process of configuring a carrier aggregation cell can be improved.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for establishing a connection between a subscriber station and a base station in a communication system supporting carrier combining,

The present invention relates to a method for establishing a connection between a terminal and a base station in a communication system supporting carrier coupling, and a technique related to the terminal and the base station.

In a typical wireless communication system, although a bandwidth between an uplink and a downlink is set to be different from each other, only one carrier is mainly considered. For example, a wireless communication system may be provided in which the number of carriers constituting the uplink and the downlink is one each based on a single carrier, and the bandwidths of the uplink and the downlink are generally symmetrical to each other.

In the advanced wireless communication system, it is required to support the extended bandwidth as compared with the existing wireless communication system. However, with the exception of some regions around the world, it is not easy to allocate a large bandwidth frequency. Therefore, in order to efficiently use a fragmented small band, a technique such as Carrier Aggregation (CA), Bandwidth Aggregation (CA), and the like is used to physically group a plurality of bands in the frequency domain and to logically use a large band. ) Or Spectrum Aggregation) technology is being developed. Here, each of the coupled carriers may be referred to as a component carrier (CC) or a cell. In addition, carrier wave combining can be applied to each of the uplink and downlink.

On the other hand, when the CA cell is configured in the base station, one cell is designated for each different frequency in the base station, or a CA cell is configured based on the frequency-dependent channel environment measured by the terminal. However, both of these methods have disadvantages of degradation of CA performance or occurrence of delay due to measurement of channel environment, respectively, and the necessity of improvement is suggested.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems of the related art, and an object of the present invention is to improve the efficiency in the process of constructing a CA cell as described above.

It is another object of the present invention to improve performance degradation due to CA coverage mismatch between different frequencies.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the particular form disclosed. ≪ / RTI >

According to another aspect of the present invention, there is provided a method of establishing a connection, the method comprising: establishing an RRC connection with a base station; instructing a blind SCell to be added to the terminal if the blind SCell Receiving an RRC connection re-establishment message from the base station, and adding a connection with the blind SCell without a measurement on the blind SCell as the RRC connection re-establishment message is received.

The connection establishment method further comprises receiving from the base station a measurement control message including information about the measurement for the added blind SCell, and performing a measurement for the blind SCell in accordance with the measurement control message.

And transmitting a measurement report message to the base station reporting an event occurring according to the trigger condition when the measurement result of the blind SCell satisfies a predetermined trigger condition.

The event includes the A2 event, the A4 event or the A6 event, and the information on the measurement includes the information of the trigger condition regarding at least one of the A2 event, the A4 event, and the A6 event.

The connection establishment method further includes a step of releasing the connection with the blind SCell or adding a connection with the new SCell based on the new RRC connection re-establishment message when a new RRC connection re-establishment message is received in response to the measurement report message.

The step of establishing an RRC connection with the base station is performed in accordance with an initial call setup with the base station of the mobile station or a handover between the PCs of the mobile station.

The connection establishment method further includes a step of adding a new SCell through the measurement process for the SCell around the UE if the blind SCell is not set in the base station.

According to an aspect of the present invention, there is provided a mobile communication system including a transmitter, a receiver, and a processor connected to a transmitter and a receiver for communicating with a base station, the processor establishing an RRC connection with the base station, ) Is set, the receiving unit is controlled to receive an RRC connection re-establishment message from the base station instructing to add a predetermined blind SCell to the UE, and when the RRC connection re-establishment message is received, the blind SCell Add the connection of.

According to another aspect of the present invention, there is provided a method of establishing a connection, the method comprising: establishing an RRC connection with a terminal; establishing a connection with a blind SCell without blind SCell if the blind SCell To the terminal, and receiving an RRC connection re-establishment complete message in response to the RRC connection re-establishment message from the terminal.

According to an aspect of the present invention, there is provided a base station including a processor connected to a transmitter, a receiver, and a transmitter and a receiver for establishing an RRC connection with the terminal, and the blind SCell ) Is set in advance, the control unit controls the transmitting unit to transmit an RRC connection reset message to the UE instructing to add a connection with the blind SCell without measurement for the predetermined blind SCell, and in response to the RRC connection reset message, And controls the receiving section to receive a connection reset completion message.

According to the embodiments of the present invention, the following effects can be expected.

First, the efficiency of CA cell configuration can be improved by selectively mixing the two methods of CA cell configuration.

Second, the performance of the CA cell configuration can be improved between different frequency cells generated according to the frequency characteristics.

Third, performance degradation due to designation of a designated cell for each base station can be improved, and delay due to channel measurement of the terminal can be improved.

The effects obtainable in the embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be obtained from the description of the embodiments of the present invention described below by those skilled in the art Can be clearly understood and understood. In other words, undesirable effects of implementing the present invention can also be obtained by those skilled in the art from the embodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. It is to be understood, however, that the technical features of the present invention are not limited to the specific drawings, and the features disclosed in the drawings may be combined with each other to constitute a new embodiment. Reference numerals in the drawings refer to structural elements.
1 is a block diagram showing the configuration of a terminal and a base station according to an embodiment of the present invention.
2 is a flow chart illustrating a connection establishment method in accordance with an embodiment of the present invention.
3 is a flow chart illustrating a connection establishment method in accordance with another embodiment of the present invention.
4 is a flowchart illustrating a connection establishment method according to another embodiment of the present invention.
5 is a flowchart illustrating a connection establishment method according to another embodiment of the present invention.
6 is a flowchart illustrating a connection establishment method according to another embodiment of the present invention.
7 is a flowchart illustrating a connection establishment method according to another embodiment of the present invention.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Also, in certain cases, there may be a term selected arbitrarily by the applicant, in which case the meaning thereof will be described in detail in the description of the corresponding invention. Therefore, the term used in the present invention should be defined based on the meaning of the term, not on the name of a simple term, but on the entire contents of the present invention.

The following embodiments are a combination of elements and features of the present invention in a predetermined form. Each component or characteristic may be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. In addition, some of the elements and / or features may be combined to form an embodiment of the present invention. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments.

In the description of the drawings, there is no description of procedures or steps that may obscure the gist of the present invention, nor is any description of steps or steps that can be understood by those skilled in the art.

Throughout the specification, when an element is referred to as " comprising " or " including ", it is meant that the element does not exclude other elements, do. In addition, the term " "... Quot ;, " module " and the like refer to a unit for processing at least one function or operation, which may be implemented by hardware, software, or a combination of hardware and software. Also, the terms " a or ", " one ", " the ", and the like are synonyms in the context of describing the invention (particularly in the context of the following claims) May be used in a sense including both singular and plural, unless the context clearly dictates otherwise.

The embodiments of the present invention have been described herein with reference to a data transmission / reception relationship between a base station and a mobile station. Here, the base station is meaningful as a terminal node of a network that directly communicates with a mobile station. The specific operation described herein as performed by the base station may be performed by an upper node of the base station, as the case may be.

That is, various operations performed for communication with a mobile station in a network consisting of a plurality of network nodes including a base station may be performed by a base station or other network nodes other than the base station. The term 'base station' may be replaced by terms such as a fixed station, a Node B, an eNode B, an Advanced Base Station (ABS), or an access point.

Also, a 'Mobile Station (MS)' may be a user equipment (UE), a subscriber station (SS), a mobile subscriber station (MSS), a mobile terminal, an advanced mobile station The term " terminal "

Also, the transmitting end refers to a fixed and / or mobile node providing data service or voice service, and the receiving end means a fixed and / or mobile node receiving data service or voice service. Therefore, in the uplink, the mobile station may be the transmitting end and the base station may be the receiving end. Similarly, in a downlink, a mobile station may be a receiving end and a base station may be a transmitting end.

Further, an indication that a device performs communication with a " cell " may mean that the device transmits and receives signals with the base station of the corresponding cell. That is, although a practical object to which a device transmits and receives a signal may be a specific base station, it may be described as transmitting and receiving signals with a cell formed by a specific base station for convenience of description. Similarly, the description 'macro cell' and / or 'small cell' may mean specific coverage, and may also refer to a 'macro cell supporting a macro cell' and / or a 'small cell supporting a small cell' Base station '.

Embodiments of the present invention may be supported by standard documents disclosed in at least one of IEEE 802.xx systems, 3GPP systems, 3GPP LTE systems and 3GPP2 systems, which are wireless access systems. That is, self-explaining steps or parts not described in the embodiments of the present invention can be described with reference to the documents.

In addition, all terms disclosed in this document may be described by the standard document. In particular, embodiments of the present invention may be supported by one or more of the standard documents P802.16e-2004, P802.16e-2005, P802.16.1, P802.16p, and P802.16.1b, which are standard documents of the IEEE 802.16 system have.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced.

In addition, the specific terminology used in the embodiments of the present invention is provided to help understanding of the present invention, and the use of such specific terminology can be changed into other forms without departing from the technical idea of the present invention.

1. Carrier Aggregation (CA) in LTE-A

The LTE-A communication system can support a wider uplink / downlink bandwidth by collecting a plurality of uplink / downlink component carriers (CCs). The term " component carrier (CC) " may be replaced by another equivalent term (e.g., carrier, cell, etc.). Each CC may be adjacent or non-adjacent to one another in the frequency domain, and the bandwidth of each component carrier may be independently determined. Asymmetric carrier aggregation with different numbers of UL CCs and DL CCs is also possible. On the other hand, the control information can be set to be transmitted and received only through a specific CC. This particular CC may be referred to as the primary CC (or anchor CC), and the remaining CC may be referred to as the secondary CC. Hereinafter, a cell supported by a base station through a primary CC is called a primary cell, and a cell supporting a secondary cell through a secondary CC is called a secondary cell.

When the cross-carrier scheduling (or cross-CC scheduling) is applied, the PDCCH for downlink allocation is transmitted to the DL CC # 0, and the PDSCH can be transmitted to the DL CC # 2. For cross-CC scheduling, the introduction of a carrier indicator field (CIF) may be considered. The presence of the CIF in the PDCCH may be semi-static and UE-specific (or UE-group-specific) by higher layer signaling (e.g., RRC signaling) ) ≪ / RTI > The baseline of the PDCCH transmission is summarized as follows.

1) CIF disabled: The PDCCH on the DL CC allocates a PDSCH resource on the same DL CC or a PUSCH resource on a single linked UL CC

1-1) No CIF

1-2) LTE PDCCH structure (same encoding, same CCE-based resource mapping) and same as DCI format

2) CIF enabled: The PDCCH on DL CC can allocate PDSCH or PUSCH resources on a specific DL / UL CC among a plurality of merged DL / UL CCs using CIF

2-1) Extended LTE DCI format with CIF

2-1-1) CIF (if set) is a fixed x-bit field (eg x = 3)

2-1-2) CIF (if set) position is fixed regardless of DCI format size

2-2) Reuse LTE PDCCH structure (same coding, same CCE-based resource mapping)

Meanwhile, when CIF for cross-CC scheduling exists in the PDCCH, the BS can allocate a PDCCH monitoring DL CC set to lower the blind decoding complexity on the UE side. The PDCCH monitoring DL CC set includes one or more DL CCs as part of the merged whole DL CCs, and the UE performs detection / decoding of the PDCCH only on the corresponding DL CCs. That is, when the BS schedules the PDSCH / PUSCH to the UE, the PDCCH is transmitted only through the PDCCH monitoring DL CC set. PDCCH Monitoring The DL CC set may be configured in a UE-specific, UE-group-specific or cell-specific manner. The term " PDCCH monitoring DL CC " may be replaced by equivalent terms such as monitoring carrier, monitoring cell, and the like. Also, the CC merged for the UE may be replaced with equivalent terms such as serving CC, serving carrier, serving cell, and so on.

As described above, LTE-A is considering using CIF within the PDCCH for cross -CC scheduling. The use of CIF (i.e., support of cross-CC scheduling mode or non-cross-CC scheduling mode) and mode-to-mode switching can be set semi-static / terminal-specific via RRC signaling. After the UE performs the RRC signaling process, the UE can recognize whether the CIF is used in the PDCCH to be scheduled.

2. Connection setup method and device configuration between terminal and base station

Hereinafter, a method of establishing a connection between a terminal and a base station in a communication system supporting the CA will be described with reference to FIG. 1 through FIG.

1 is a block diagram showing the configuration of a terminal and a base station according to an embodiment of the present invention.

1, terminal 100 and base station 150 may include radio frequency (RF) units 110 and 160, processors 116 and 166, and memories 118 and 168, respectively. 1 illustrates a 1: 1 communication environment between a terminal 100 and a base station 150, a communication environment can be established between a plurality of terminals and a base station 150. [

Each of the RF units 110 and 160 may include transmitters 112 and 162 and receive units 114 and 164, respectively. The transmitter 112 and the receiver 114 of the terminal 100 are configured to transmit and receive signals to and from the base station 150 and other terminals and the processor 116 is operatively coupled to the transmitter 112 and the receiver 114, And controls transmission and reception of signals between the transmitting unit 112 and the receiving unit 114 with other devices. In addition, the processor 116 performs various processes on the signal to be transmitted, and then transmits the processed signal to the transmitting unit 112, and performs processing on the signal received by the receiving unit 114.

If desired, the processor 116 may store information contained in the exchanged message in the memory 118. With this structure, the terminal 100 can perform the connection establishment method of various embodiments of the present invention described below.

The transmitter 162 and the receiver 164 of the base station 150 are configured to transmit and receive signals to and from other base stations and terminals and the processor 166 is functionally connected to the transmitter 162 and the receiver 164, The control unit 162 and the receiving unit 164 may control the process of transmitting and receiving signals with other devices. The processor 166 may perform various processes on the signal to be transmitted, transmit the signal to the transmitter 162, and process the signal received by the receiver 164. If desired, the processor 166 may store information contained in the exchanged message in the memory 168. Having such a structure, the base station 150 can perform connection establishment methods of various embodiments to be described below.

The processors 116 and 166 of the terminal 100 and the base station 150 respectively instruct (for example, control, adjust, manage, etc.) the operation in the terminal 100 and the base station 150. Each processor 116, 166 may be coupled to a memory 118, 168 that stores program codes and data. The memories 118 and 168 are connected to the processors 116 and 166 to store operating systems, applications, and general files.

The processors 116 and 166 of the present invention may also be referred to as a controller, a microcontroller, a microprocessor, a microcomputer, or the like. Meanwhile, the processors 116 and 166 may be implemented by hardware or firmware, software, or a combination thereof. (DSP), digital signal processing devices (DSPDs), programmable logic devices (PLDs), and the like may be used to implement embodiments of the present invention using hardware, , Field programmable gate arrays (FPGAs), and the like may be provided in the processors 116 and 166.

2 to 7 are flowcharts illustrating a connection establishment method according to an embodiment of the present invention. 2 to 7, a description will be made of a series of processes in which a terminal and a base station establish a connection and perform communication using the configurations of the terminal 100 and the base station 150 described in FIG. &Quot; UE " shown in FIGS. 2 to 5 denotes a terminal according to an embodiment of the present invention, and " eNB " denotes a base station according to an embodiment of the present invention.

2 is a flowchart illustrating a connection establishment method according to an embodiment of the present invention. FIG. 2 illustrates and explains a sequence of initial call setup with the base station.

First, the MS transmits an RRC connection request message to the BS (S210). The RRC connection request message is a message requesting the UE to establish an RRC connection with the BS, and the BS transmits an RRC connection setup message to the MS in response to the RRC connection setup message (S220). The BS may transmit a negative response to the UE indicating that the RRC connection can not be established with respect to the RRC connection request message of the UE. However, in the illustrated embodiment, the BS transmits an RRC connection setup message, Lt; / RTI >

In step S230, the MS transmits an RRC connection completion message indicating that the RRC connection state with the BS has been switched from the RRC idle state to the RRC connected state according to the RRC connection setup message of the base station. . It can be said that the RRC connection between the terminal and the base station is established through the processes of S210 to S230.

If an RRC connection is established between the subscriber station and the base station, the base station transmits an RRC connection re-establishment message to the subscriber station (S240). The RRC connection re-establishment message can be transmitted to the UE when the blind SCell is preset in the base station, and is a message instructing to add the predetermined blind SCell to the UE.

'Blind SCell' means a SCell to be connected to the base station by an operator or a user, or a predetermined SCell internally in the system, without a measurement process according to an RRC connection with the terminal. That is, when an RRC connection between a terminal and a base station is established and information on the blind SCell is received by the terminal, the terminal can immediately add a connection with the blind SCell. In other words, a blind SCell may mean a SCell to be connected by default when an RRC connection between a UE and a BS is established.

That is, in step S240, the BS transmits an RRC connection reset message including information on the blind SCell preset in the BS to the MS. Upon receiving the RRC connection reset message, the MS adds a connection with the blind SCell without measuring the blind SCell I have been instructed to do so. Accordingly, the MS adds a connection with the blind SCell without a measurement process for the blind SCell, and transmits an RRC connection reset completion message indicating that a connection with the blind SCell has been added to the BS (S250).

On the other hand, since the connection to the blind SCell is added to the terminal without the measurement process for the blind SCell, a radio channel environment sufficient to perform communication between the blind SCell and the terminal can not be guaranteed. Accordingly, the base station transmits a measurement control message including information related to the measurement to the terminal so that the terminal can perform measurement on the newly added blind SCell (S260). The measurement control message may include information on a threshold value, an offset value, and the like for determining whether a trigger condition of a specific event is satisfied when the UE performs measurement with the blind SCell. Although not explicitly shown, the terminal may perform measurements on the blind SCell using the information contained in the measurement control message received in S260.

As described in FIG. 2, if the blind SCell is preset in the base station, the terminal can add a connection with the blind SCell without measuring the blind SCell. On the other hand, if blind SCell is not set in the base station, after the RRC connection is established, the terminal adds the connection with the SCell through the measurement process of the surrounding SCell. As described above, the process of setting the SCell in the terminal in each of the two cases is performed differently, and this series of processes may be referred to as an adaptive CA (adaptive CA).

FIG. 3 and FIG. 4 illustrate a process of the UE performing the measurement on the blind SCell following the embodiment illustrated in FIG. 2. FIG. FIG. 3 illustrates an embodiment in which the UE transmits a measurement report message according to the A2 event and the A4 event, and FIG. 4 illustrates an embodiment in which the UE transmits a measurement report message according to the A6 event.

First, the measurement of the blind SCell based on the measurement control message received from the base station by the terminal has been described with reference to S260 in FIG. Such a measurement control message may include information of a trigger condition for at least one of an A2 event, an A4 event, and an A6 event. In addition, the information on the trigger condition may include a threshold value, an offset value, and the like used in calculating the satisfaction of the trigger condition described above.

Specifically, the UE performs a measurement process for the blind SCell according to the measurement control message received in S260 of FIG. Measurement Results for Blind SCell When the UE is provided with a radio channel environment sufficient to perform communication with the BS through the blind SCell, the UE can receive the service from the BS without transmitting the measurement report message. However, if the channel condition with the blind SCell is not sufficient to perform the communication (for example, when the trigger condition of the A2 event is satisfied as a result of measurement with reference to the measurement control message) To the base station, an A2 measurement report message indicating that the channel environment of the base station is deteriorated (S310).

Upon receiving the A2 measurement report message, the BS confirms that the connection between the blind SCell added to the UE and the UE is not good, and transmits an RRC connection re-establishment message to the UE for releasing the connection between the blind SCell and the UE in step S320. The RRC connection reset message at S320 may be a message instructing the UE to remove the connection with the blind SCell. Upon receiving the RRC connection re-establishment message, the MS releases the connection with the blind SCell and transmits an RRC connection re-establishment completion message to the BS in step S330.

Meanwhile, since the connection between the terminal and the SCell is released, the base station transmits an A4 measurement control message to the terminal to add a new SCell to the terminal (S340). The A4 measurement control message may include information on the trigger condition of the A4 event for adding the connection with the new SCell through the measurement process of the peripheral SCell.

The terminal receiving the A4 measurement control message confirms that the wireless communication environment with the new SCell is good enough to perform the communication by performing the measurement process for the new SCell (for example, satisfying the trigger condition of the A4 event Occation). Subsequently, the terminal transmits an A4 measurement report message to the base station indicating that the A4 event trigger condition for the predetermined SCell is satisfied (S350).

After receiving the A4 measurement report message, the BS transmits an RRC connection reset message to the MS (S360) indicating that a connection with the new SCell should be added (S360). The MS adds a connection with the new SCell and then transmits an RRC connection reset completion message To the base station (S370).

Fig. 4 illustrates an embodiment related to the A6 event. The terminal may perform measurements on the blind SCell and the new SCell based on the measurement control message received from the base station in S260 of FIG. If it is determined that the wireless communication environment with the new SCell is better than the predetermined offset value (included in the measurement control message of S260) than the wireless communication environment with the blind SCell, (E.g., a message indicating that the trigger condition of the A6 event is satisfied) to the base station (S410).

In step S420, the BS receiving the RLC connection re-establishment message transmits an RRC connection re-establishment message to the MS in order to release the connection with the blind SCell and to add a connection with the new SCell. That is, the base station can instruct the terminal to modify the SCell. The MS releases the connection with the blind SCell according to the received RRC connection re-establishment message, adds a connection with the new SCell, and transmits an RRC connection re-establishment completion message to the BS in response to the RRC connection re-establishment message ).

2 to 4, a connection establishment method according to the initial call setup between the terminal and the base station has been described. In FIG. 5, a connection establishment method according to the PCell handover of the terminal will be described. Although the detailed description is omitted in the embodiment shown in FIG. 5, the embodiments described in FIGS. 2 to 4 can be applied equally or similarly.

First, the terminal performs handover to a new cell (S510). The target cell to be handed over may be PCell. FIG. 5 shows the case where the blind SCell is set to the target PCell and the case where the blind SCell is not set, respectively. In the box shown in the upper part of FIG. 5, the blind SCell is set to the target PCell (when the adaptive CA is applied) and the lower box is set to the case where the blind SCell is not set (when the adaptive CA is not applied) Respectively.

The case where the blind SCell is set in the base station will be described first. When the connection between the MS and the new PCell is established, the BS transmits an RRC connection re-establishment message to the MS (S520). This RRC connection reset message may be a message instructing the base station to add a connection with the blind SCell predetermined. The UE adds a connection with the blind SCell without performing a measurement on the blind SCell, and then transmits an RRC connection reset completion message to the base station indicating that a connection with the blind SCell is added (S530). Meanwhile, since the connection to the blind SCell is added to the terminal without measuring the blind SCell, the base station instructs the terminal to perform the measurement on the blind SCell by transmitting the A2 / A6 measurement control message to the terminal (S540). That is, the BS may transmit information on a threshold value or an offset value to the UE for determining whether the trigger condition for a predetermined event is satisfied through the measurement on the blind SCell.

Next, a case where the blind SCell is not set in the base station will be described. Unlike the above embodiment, when the blind SCell is not set in the base station, the UE performs a measurement process for SCell before adding a new SCell. That is, when the MS completes the handover to the PCell of the BS, the BS instructs the MS to measure whether the SCell can provide a sufficient wireless communication environment for performing the communication. This process can be performed by the base station transmitting an A4 measurement control message to the terminal (S550). After receiving the A4 measurement control message, the UE confirms that it can provide a sufficient quality service through the measurement process of the new SCell, and transmits an A4 measurement report message to the base station (S560). Upon receipt of the A4 measurement report message, the BS transmits an RRC connection reset message to the MS (S570), which instructs to add a connection with the reported SCell (S570). The MS adds a connection with a new SCell and then transmits an RRC connection reset completion message To the base station (S580).

FIG. 6 and FIG. 7 are flowcharts illustrating a connection establishment method performed in each of the terminal and the base station in the embodiment in which the adaptive CA is applied. FIG. 6 shows a series of processes performed by the terminal, and FIG. 7 shows a series of processes performed by the base station.

6, when the RRC connection with the BS is established (S610), the MS receives an RRC connection re-establishment message from the BS. If the RRC connection reset message received from the base station includes information on the blind SCell, the terminal adds a connection with the blind SCell without measuring the blind SCell (S620). Meanwhile, the BS may instruct the MS to perform the measurement on the blind SCell, and the MS performs the measurement on the blind SCell according to the instruction of the BS (S630).

FIG. 7 illustrates a connection establishment method of a base station in accordance with a connection establishment method of a terminal in FIG. When the RRC connection with the MS is established (S710), the BS operates differently depending on whether the blind SCell is already set in the BS (S720). When the blind SCell is set, the BS transmits an RRC connection reset message to the terminal, which instructs the terminal to add a connection with the blind SCell without a measurement process (S730). When a connection between the terminal and the blind SCell is added, And transmits a measurement control message to the terminal (S740). On the other hand, if blind SCell is not set in the base station, the base station transmits an A4 measurement control message for adding a new SCell to the terminal (S750). In both cases, the base station resets the RRC connection according to the measurement report message received from the terminal as a response to the measurement control message (S760). The S760 may be a process of disconnecting from a SCell added to a terminal or a process of adding a connection with a new SCell.

On the other hand, the above-described method can be implemented in a general-purpose digital computer that can be created as a program that can be executed in a computer and operates the program using a computer-readable medium. Further, the structure of the data used in the above-described method can be recorded on the computer-readable medium through various means. Program storage devices that may be used to describe a storage device including executable computer code for carrying out the various methods of the present invention should not be understood to include transient objects such as carrier waves or signals . The computer-readable medium includes a storage medium such as a magnetic storage medium (e.g., ROM, floppy disk, hard disk, etc.), optical readable medium (e.g., CD-ROM, DVD, etc.).

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed methods should be considered in an illustrative rather than a restrictive sense. It is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims (16)

A method for establishing a connection with a base station (BS) in a communication system supporting CA (Carrier Aggation)
The terminal establishing an RRC connection with the base station;
Receiving, from the base station, an RRC connection re-establishment message instructing to add the predetermined blind SCell to the terminal if blind SCell is preset in the base station; And
Adding a connection with the blind SCell without measuring for the blind SCell as the RRC connection reestablishment message is received. The method according to claim 1,
The connection establishment method
Receiving a measurement control message from the base station, the measurement control message including information about measurements for the added blind SCell; And
Further comprising: performing a measurement on the blind SCell in accordance with the measurement control message. 3. The method of claim 2,
Further comprising transmitting to the base station a measurement report message reporting an event occurring according to the trigger condition if the measurement result of the blind SCell satisfies a predetermined trigger condition. The method of claim 3,
Wherein the event includes an A2 event, an A4 event, or an A6 event, and the information about the measurement includes information of a trigger condition related to at least one of the A2 event, the A4 event, and the A6 event. . The method of claim 3,
The connection establishment method
Further comprising, when a new RRC connection reestablishment message is received in response to the measurement report message, releasing the connection with the blind SCell or adding a connection with the new SCell based on the new RRC connection reestablishment message How to set it up. The method according to claim 1,
The step of establishing an RRC connection with the base station
Wherein the initialization is performed in accordance with an initial call setup of the terminal with the base station or a handover between PCs of the terminal. The method according to claim 1,
The connection establishment method
Further comprising the step of adding a new SCell through a measurement process for the SCell around the terminal if the blind SCell is not previously set in the base station. 1. A terminal establishing a connection with a base station in a communication system supporting CA (Carrier Aggation)
A transmitting unit;
A receiving unit; And
And a processor connected to the transmitter and the receiver for performing communication with the base station,
The processor
Establishing an RRC connection with the base station,
Controlling the receiving unit to receive from the base station an RRC connection re-establishment message instructing to add the predetermined blind SCell to the terminal if blind SCell is preset in the base station,
And adds a connection with the blind SCell without measuring for the blind SCell as the RRC connection reestablishment message is received. 9. The method of claim 8,
The processor
Controlling the receiver to receive a measurement control message from the base station, the measurement control message including information about measurement for the added blind SCell,
And performs a measurement on the blind SCell according to the measurement control message. 10. The method of claim 9,
The processor
And controls the transmission unit to transmit a measurement report message to the base station, the measurement report message reporting an event occurring according to the trigger condition when the measurement result of the blind SCell satisfies a predetermined trigger condition. 11. The method of claim 10,
Wherein the event includes an A2 event, an A4 event, or an A6 event, and the information about the measurement includes information of a trigger condition related to at least one of the A2 event, the A4 event, and the A6 event. 11. The method of claim 10,
The processor
And when a new RRC connection reestablishment message is received in response to the measurement report message, disconnects the connection with the blind SCell or adds a connection with a new SCell based on the new RRC connection reestablishment message. 9. The method of claim 8,
The RRC connection with the base station
Wherein the terminal is set up in accordance with an initial call setup of the terminal with the base station or a handover between PCs of the terminal. 9. The method of claim 8,
The processor
Wherein when a blind SCell is not set in the base station, a new SCell is added through a measurement process for the SCell around the terminal. A method for establishing a connection with a base station (BS) in a communication system supporting CA (Carrier Aggation)
Establishing an RRC connection with the terminal;
Transmitting a RRC connection reestablishment message to the terminal instructing to add a connection with the blind SCell without a measurement on the predetermined blind SCell when blind SCell is preset in the base station; And
And receiving an RRC connection reestablishment completion message in response to the RRC connection reestablishment message from the terminal. A base station establishing a connection with a terminal in a communication system supporting CA (Carrier Aggation)
A transmitting unit;
A receiving unit; And
And a processor connected to the transmitter and the receiver for performing communication with the terminal,
The processor
Establishes an RRC connection with the terminal,
When the blind SCell is preset in the base station, transmits the RRC connection re-establishment message to the terminal instructing to add a connection with the blind SCell without measurement on the predetermined blind SCell Control,
And controls the receiver to receive an RRC connection re-establishment completion message in response to the RRC connection re-establishment message from the terminal.

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