WO2012081923A2

WO2012081923A2 - Apparatus and method for performing wireless connection re-establishment in a multiple component carrier system

Info

Publication number: WO2012081923A2
Application number: PCT/KR2011/009688
Authority: WO
Inventors: 권기범; 정명철
Original assignee: 주식회사 팬택
Priority date: 2010-12-16
Filing date: 2011-12-15
Publication date: 2012-06-21
Also published as: WO2012081923A3

Abstract

Provided are an apparatus and a method for performing wireless connection re-establishment in a multiple component carrier system. The present description discloses a terminal comprising: a cell selection unit which selects a cell for said wireless connection re-establishment upon occurrence of failure of wireless connection; a sub-serving cell setting information constructing unit which constructs sub-serving cell setting information for specifying at least one sub-serving cell set for the terminal; a message transmitting unit which transmits a wireless connection re-establishment request message for requesting procedures for the wireless connection re-establishment and a wireless connection re-establishment completion message indicating the completion of the procedures for the wireless connection re-establishment, to a base station through the selected cell; and a message receiving unit which receives a wireless connection re-establishment message as a response to said wireless connection re-establishment request message. According to the present invention, RRC connection re-establishment procedures are performed using sub-serving cell setting information, and therefore, change of configuration of the sub-serving cell which has been already set between the terminal and the base station may be performed without exchanging any additional message when the sub-serving cell is added/changed/removed.

Description

Device and method for performing wireless connection reset in multi-element carrier system

The present invention relates to wireless communications, and more particularly, to an apparatus and method for performing radio connection reconfiguration in a multi-component carrier system.

The next generation mobile communication system aiming at providing various multimedia services should guarantee a certain level or more of quality for each service provided by subscribers. The overall quality of a service, which determines the user's satisfaction with a particular service, is defined as a quality of service (QoS). QoS is determined by various and complex factors applied to each service.

The wireless network defines and uses various bearer services to guarantee a certain level of QoS for end-to-end (user-to-user or user-server) services. The end-to-end service is divided into several sections through various network components, so that data transmission services in each section can be defined independently to guarantee QoS. Therefore, the radio connection service for the transmission of data provided in a specific interval is defined as a bearer service.

A radio bearer (RB) is a bearer service related to the operation of a radio interface protocol, and is a service provided to a higher protocol layer through a radio resource control (RRC) layer of a radio interface protocol. . Radio bearers include a data radio bearer (DRB) and a signaling radio bearer (SRB). The data radio bearer is a radio bearer in charge of providing a data service, and the signaling radio bearer is a radio bearer in charge of transmitting various RRC messages required for establishing an RRC connection with a radio network in order to provide a data radio bearer service. That is, the signaling radio bearer is distinguished from the data radio bearer that is responsible for the transmission of user data.

In order for the UE to receive a DRB service, an SRB for RRC connection must first be configured. However, even when the RRC connection is established, data loss may occur in the wireless channel when the channel state is unstable. This loss of data causes an error in the SRB or DRB between the terminal and the base station.

Meanwhile, in a plurality of CC carriers, one or more serving cells may be configured and configured between a base station and a terminal. In such a system, when a problem of a radio resource control channel between a base station and a terminal occurs temporarily due to deterioration of a radio channel, secondary serving cells other than a primary serving cell to which a radio resource control channel is set The method for resetting has not yet been determined.

An object of the present invention is to provide an apparatus and method for performing radio connection reconfiguration in a multi-component carrier system.

Another technical problem of the present invention is to provide an apparatus and method for resetting a radio resource control channel capable of recovering all possible serving cells when there are serving cells other than a serving cell for which a radio resource control channel is set.

According to an aspect of the present invention, a terminal for performing radio connection reconfiguration in a multi-component carrier system is provided. The terminal includes a cell selector for selecting a cell for resetting a radio connection and secondary serving cell configuration information for configuring secondary serving cell configuration information for specifying at least one secondary serving cell set in the terminal. A configuration unit, a message transmitter for transmitting a radio connection reset request message including the secondary serving cell setting information and a radio connection reset complete message indicating completion of a radio connection reset procedure to a base station through the selected cell, and the radio And a message receiver configured to receive the radio connection reset message in response to the connection reset request message.

According to another aspect of the present invention, a method for performing radio connection reconfiguration by a terminal in a multi-component carrier system is provided. The method includes selecting a cell for resetting a wireless connection, configuring secondary cell setting information specifying at least one secondary serving cell set in a terminal, and requesting a radio connection resetting including the secondary cell setting information. Transmitting a message to the base station through the selected cell, receiving a radio connection reset message in response to the radio link reset request message, and receiving a radio link reset complete message indicating completion of a radio link reset procedure; Transmitting to the base station through the selected cell.

According to another aspect of the present invention, there is provided a base station for performing radio connection reconfiguration in a multi-component carrier system. The base station may provide a radio connection reset request message including secondary serving cell configuration information specifying at least one secondary serving cell configured in the terminal, or a radio connection reset complete message indicating completion of a radio connection reset procedure. Primary Serving Cell) uplink message receiving unit received from the terminal, with reference to the secondary serving cell configuration information to determine whether to remove or change the at least one secondary serving cell, adding the secondary serving cell based on the determination, The secondary serving cell change information constituting unit for configuring secondary serving cell change information indicating removal or change, and in response to the wireless connection reset request message, the terminal receives a wireless connection reset message including the secondary serving cell change information. It includes a downlink message transmitter for transmitting to.

According to another aspect of the present invention, there is provided a method for performing radio connection reconfiguration by a base station in a multi-component carrier system. The method may further include receiving, from a terminal, a radio connection reconfiguration request message including secondary serving cell configuration information specifying at least one secondary serving cell configured in the terminal, through a primary serving cell, with reference to the secondary serving cell configuration information. Determining whether to remove or change at least one secondary serving cell; configuring secondary serving cell change information indicating addition, removal or change of the secondary serving cell based on the determination; In response, transmitting a radio connection reset message including the secondary serving cell change information to the terminal, and receiving a radio connection reset complete message indicating completion of a radio connection reset procedure from the terminal through the main serving cell. It includes a step.

According to another aspect of the present invention, a terminal for performing radio connection reconfiguration in a multi-component carrier system is provided. The terminal configures a cell selection unit for selecting a cell for resetting the wireless connection when the wireless connection fails, and secondary cell setting information for specifying at least one secondary serving cell set in the terminal. A secondary serving cell configuration information configuration unit, a wireless connection reset request message requesting a reset procedure of the wireless connection and a message for transmitting a wireless connection reset complete message indicating that the reset procedure of the wireless connection is completed to the base station through the selected cell; A transmitter and a message receiver for receiving a radio connection reset message in response to the radio link reset request message.

The secondary serving cell setting information may be included in any one of the radio connection reset request message and the radio connection reset complete message.

According to another aspect of the present invention, there is provided a method for performing radio connection reconfiguration by a terminal in a multi-component carrier system. The method includes selecting a cell for resetting the wireless connection when the wireless connection fails, configuring secondary cell setting information for specifying at least one secondary serving cell set in the terminal, requesting the resetting of the wireless connection. Transmitting a radio link reset request message to a base station through the selected cell, receiving a radio link reset message in response to the radio link reset request message, and performing a radio link reset procedure; And transmitting a reset complete message to the base station through the selected cell.

According to another aspect of the present invention, there is provided a base station for performing radio connection reconfiguration in a multi-component carrier system. The base station receives an uplink message from a mobile station through a primary serving cell (Primary Serving Cell) that receives a radio connection reset request message for requesting a radio link reset or a radio link reset complete message indicating completion of a radio link reset procedure. The receiver, included in at least one of the radio connection reset request message and the radio connection reset complete message, the at least one secondary serving cell with reference to secondary serving cell configuration information specifying at least one secondary serving cell set in the terminal Determining whether or not to change or change, and based on the determination, the secondary serving cell change information configuration unit for configuring the secondary serving cell change information indicating addition, removal or change of the secondary serving cell, and for the wireless connection reset request message In response, the wireless connection reset message including the secondary serving cell change information is received. It includes a downlink message transmission unit for transmitting to the base station.

According to another aspect of the present invention, there is provided a method for performing radio connection reconfiguration by a base station in a multi-component carrier system. The method may further include receiving a radio connection reset request message requesting the reset of the radio connection or a radio connection reset complete message indicating that the reset of the radio connection is completed from the terminal through the main serving cell when the radio connection fails. The at least one secondary serving cell is included in at least one of a radio connection reset request message and a radio connection reset complete message, and the at least one secondary serving cell is removed based on the secondary serving cell configuration information specifying at least one secondary serving cell set in the terminal. And transmitting, to the terminal, a radio connection reset message including secondary serving cell change information indicating whether to change.

If the secondary serving cell information in the carrier aggregation environment in the previous carrier aggregation (CA) environment and the RRC connection resetting procedure is different, the sub-cell previously configured between the UE and the base station by using the secondary serving cell configuration information during the RRC connection resetting procedure Configuration change by adding / modifying / removing the serving cell can be performed without additional message exchange.

1 is a block diagram illustrating a wireless communication system to which the present invention is applied.

2 is an explanatory diagram illustrating the same intra-band contiguous carrier aggregation to which the present invention is applied.

3 is an explanatory diagram illustrating the same in-band non-contiguous carrier aggregation to which the present invention is applied.

4 is an explanatory diagram illustrating the same inter-band carrier aggregation to which the present invention is applied.

5 shows an example of a protocol structure for supporting multiple carriers to which the present invention is applied.

6 shows an example of a frame structure for multi-carrier operation to which the present invention is applied.

7 shows linkage between a downlink component carrier and an uplink component carrier in a multi-carrier system to which the present invention is applied.

8 is an explanatory diagram illustrating the concept of a serving cell and a neighbor cell to which the present invention is applied.

9 is an explanatory diagram illustrating the concept of a primary serving cell and a secondary serving cell to which the present invention is applied.

10 is a flowchart illustrating an RRC connection reconfiguration procedure according to an embodiment of the present invention.

11 is a flowchart illustrating an RRC connection reconfiguration of a terminal according to an embodiment of the present invention.

12 is a flowchart illustrating an RRC connection reconfiguration of a terminal according to another embodiment of the present invention.

13 is a flowchart illustrating an RRC connection reconfiguration of a base station according to an embodiment of the present invention.

14 is a flowchart illustrating a RRC connection reconfiguration of a base station according to another example of the present invention.

15 illustrates a scenario in which a setting of a serving cell is changed according to an embodiment of the present invention.

16 illustrates a scenario in which a setting of a serving cell is changed according to another example of the present invention.

17 illustrates a scenario in which a setting of a serving cell is changed according to another example of the present invention.

18 is a block diagram illustrating a terminal and a base station for performing RRC connection reconfiguration according to an embodiment of the present invention.

Hereinafter, some embodiments will be described in detail with reference to the accompanying drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the embodiments of the present specification, when it is determined that a detailed description of a related well-known configuration or function may obscure the gist of the present specification, the detailed description thereof will be omitted.

In addition, in describing the component of this specification, terms, such as 1st, 2nd, A, B, (a), (b), can be used. These terms are only for distinguishing the components from other components, and the nature, order or order of the components are not limited by the terms. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected or connected to that other component, but between components It will be understood that may be "connected", "coupled" or "connected".

In addition, the present specification describes a wireless communication network, the operation performed in the wireless communication network is performed in the process of controlling the network and transmitting data in the system (for example, the base station) that is in charge of the wireless communication network, or the corresponding wireless Work may be done at the terminal coupled to the network.

1 is a block diagram illustrating a wireless communication system to which the present invention is applied. This may be a network structure of an Evolved-Universal Mobile Telecommunications System (E-UMTS). The E-UMTS system may be referred to as a Long Term Evolution (LTE) system. The wireless communication system is widely deployed to provide various communication services such as voice, packet data, and the like.

On the other hand, there is no limitation on the multiple access scheme applied to the wireless communication system. 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), OFDM- FDMA, OFDM-TDMA For example, various multiple access schemes such as OFDM-CDMA may be used.

Here, the uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme that is transmitted using different times, or may use a frequency division duplex (FDD) scheme that is transmitted using different frequencies. .

First, referring to FIG. 1, referring to FIG. 1, the wireless communication system 10 is widely deployed to provide various communication services such as voice and packet data. The wireless communication system 10 includes at least one base station (BS) 11. Each base station 11 provides a communication service for a particular geographic area or frequency area (generally called a cell) 15a, 15b, 15c. The cell can in turn be divided into a number of regions (called sectors).

The UE 12 may be fixed or mobile, and may have a mobile station (MS), an advanced MS (AMS), a user terminal (UT), a subscriber station (SS), a wireless device, or a wireless device. It may be called other terms such as a modem and a handheld device.

The base station 11 generally refers to a station communicating with the terminal 12, and includes an evolved-NodeB (eNodeB), a Base Transceiver System (BTS), an Access Point, a Relay, a femto base station Other terms such as Femto BS). The base station 11 may provide a service for at least one cell. The cell is an area where the base station 11 provides a communication service. An interface for transmitting user traffic or control traffic may be used between the base stations 11.

In the following, downlink means communication from the base station 11 to the terminal 12, and uplink means communication from the terminal 12 to the base station 11. The downlink is also called a forward link, and the uplink is also called a reverse link. In downlink, the transmitter may be part of the base station 11 and the receiver may be part of the terminal 12. In uplink, the transmitter may be part of the terminal 12 and the receiver may be part of the base station 11.

The base stations 11 may be connected to each other via an X2 interface, and the X2 interface is used to exchange messages between the base stations 11. The base station 11 is connected to an evolved packet system (EPS), more specifically, a mobility management entity (MME) / serving gateway (S-GW) through an S1 interface. The S1 interface supports a many-to-many-relation between the base station 11 and the MME / S-GW. The PDN-GW is used to provide packet data services to the MME / S-GW. The PDN-GW depends on the purpose or service of communication, and the PDN-GW supporting a specific service can be found using APN information.

Inter-E-UTRAN handover is a basic handover mechanism used for handover between E-UTRAN access networks. It is composed of X2 based handover and S1 based handover. X2-based handover is used when the UE intends to handover from a source BS to a target BS using an X2 interface, where the MME / S-GW is not changed.

By S1 based handover, the first bearer set between the P-GW, MME / S-GW, source base station and terminal 12 is released, and the P-GW, MME / S-GW, target is released. A new second bearer is established between the base station and the terminal 12.

Carrier aggregation (CA) supports a plurality of carriers, also referred to as spectrum aggregation or bandwidth aggregation. Individual unit carriers bound by carrier aggregation are called component carriers (CC). Each CC is defined by a bandwidth and a center frequency. Carrier aggregation is introduced to support increased throughput, to prevent cost increase due to the introduction of wideband radio frequency (RF) devices, and to ensure compatibility with existing systems.

For example, if five carriers having a bandwidth of 5 MHz are allocated, it can support a bandwidth of 25 MHz.

Carrier aggregation includes intra-band contiguous carrier aggregation as shown in FIG. 2, non-contiguous carrier aggregation as shown in FIG. 3, and inter-band as shown in FIG. band) can be divided into carrier aggregation.

First, referring to FIG. 2, in-band adjacent carrier aggregation is achieved between successive CCs in the same operating band. For example, the aggregated CCs CC # 1, CC # 2, CC # 3, ..., CC #N are all adjacent.

Referring to FIG. 3, in-band non-adjacent carrier aggregation is achieved between discrete CCs. For example, the aggregated CCs CC # 1 and CC # 2 are spaced apart from each other by a specific frequency.

Referring to FIG. 4, when a plurality of CCs exist, one or more CCs are aggregated on different frequency bands. For example, CC # 1, which are aggregated CCs, exist in operating band # 1, and CC # 2 exists in operating band # 2.

The number of carriers aggregated between the downlink and the uplink may be set differently. The case where the number of downlink CCs and the number of uplink CCs are the same is called symmetric aggregation, and when the number is different, it is called asymmetric aggregation.

In addition, the size (ie bandwidth) of the CCs may be different. For example, assuming that 5 CCs are used for a 70 MHz band configuration, 5 MHz CC (carrier # 0) + 20 MHz CC (carrier # 1) + 20 MHz CC (carrier # 2) + 20 MHz CC (carrier # 3) It may be configured in the form of + 5MHz CC (carrier # 4).

Hereinafter, a multiple carrier system refers to a system supporting carrier aggregation. Adjacent carrier aggregation and / or non-adjacent carrier aggregation may be used in a multi-carrier system, and either symmetric aggregation or asymmetric aggregation may be used.

Referring to FIG. 5, the common medium access control (MAC) entity 510 manages a physical layer 520 using a plurality of carriers. The MAC management message transmitted on a specific carrier may be applied to other carriers. That is, the MAC management message is a message capable of controlling other carriers including the specific carrier. The physical layer 520 may operate in a time division duplex (TDD) and / or a frequency division duplex (FDD).

There are several physical control channels used in the physical layer 520. A physical downlink control channel (PDCCH) for transmitting physical control information is a HARQ (hybrid automatic repeat) associated with a resource allocation of a paging channel (PCH) and a downlink shared channel (DL-SCH) and DL-SCH to a UE. request) Provides information. The PDCCH may carry an uplink grant informing the UE of resource allocation of uplink transmission.

The physical control format indicator channel (PCFICH) informs the UE of the number of OFDM symbols used for PDCCHs and is transmitted every subframe. PHICH (physical Hybrid ARQ Indicator Channel) carries a HARQ ACK / NAK signal in response to uplink transmission. Physical uplink control channel (PUCCH) carries uplink control information such as HARQ ACK / NAK, scheduling request, and CQI for downlink transmission. Physical uplink shared channel (PUSCH) carries an uplink shared channel (UL-SCH).

Referring to FIG. 6, a radio frame includes 10 subframes. The subframe includes a plurality of OFDM symbols. Each CC may have its own control channel (eg, PDCCH). CCs may or may not be adjacent to each other. The terminal may support one or more CCs according to its capability.

The CC may be divided into a fully configured CC and a partially configured CC according to directionality. The preconfigured CC refers to a carrier capable of transmitting and / or receiving all control signals and data on a bidirectional carrier, and the partial set CC refers to a carrier capable of transmitting only downlink data on a unidirectional carrier. The partially configured CC may be mainly used for a multicast and broadcast service (MBS) and / or a single frequency network (SFN).

Referring to FIG. 7, in downlink, downlink component carriers (hereinafter, referred to as DL CCs) D1, D2, and D2 are aggregated, and in uplink, uplink component carriers (hereinafter, referred to as UL CCs) U1, U2, and U3 are represented. Are concentrated. Where Di is an index of DL CC and Ui is an index of UL CC (i = 1, 2, 3).

In the FDD system, the DL CC and the UL CC are configured to be connected 1: 1, D1 is connected to U1, D2 is set to U2, and D3 is set to 1: 1 to U3. The UE establishes a connection between the DL CCs and the UL CCs through system information transmitted through a logical channel BCCH or a UE-specific RRC message transmitted by a DCCH. Each connection configuration may be set cell specific or UE specific.

An example of an UL CC connected to a DL CC is as follows.

1) a UL CC to which the terminal transmits ACK / NACK information on data transmitted by the base station through the DL CC,

2) a DL CC to which the base station transmits ACK / NACK information with respect to data transmitted by the terminal through the UL CC,

3) when the UE, which starts the random access procedure, receives a random access preamble (RAP) transmitted through the UL CC, the DL CC to transmit a response thereto;

4) When the base station transmits uplink control information through the DL CC, it is a UL CC to which the uplink control information is applied.

FIG. 7 illustrates only a 1: 1 connection setting between a DL CC and an UL CC, but it is a matter of course that a connection setting of 1: n or n: 1 may be established. In addition, the index of the component carrier does not correspond to the order of the component carrier or the position of the frequency band of the component carrier.

Referring to FIG. 8, a system frequency band is divided into a plurality of carrier frequencies. Here, the carrier frequency means a center frequency of a cell. A cell may mean a downlink frequency resource and an uplink frequency resource. Alternatively, the cell may mean a combination of a downlink frequency resource and an optional uplink frequency resource. In addition, in general, when a CA is not considered, one cell always has a pair of uplink and downlink frequency resources.

Here, the serving cell 805 refers to a cell in which a terminal is currently receiving a service. The adjacent cell refers to a cell adjacent to the serving cell 805 in a geographical or frequency band. Adjacent cells using the same carrier frequency based on the serving cell 805 are called

intra-frequency neighbor cells

800 and 810. In addition, adjacent cells using different carrier frequencies based on the serving cell 805 are called

inter-frequency neighbor cells

815, 820, and 825. That is, not only a cell using the same frequency as the serving cell but also a cell using a different frequency, all of the cells adjacent to the serving cell may be referred to as adjacent cells.

The downlink component carrier may configure one serving cell, or the downlink component carrier and the uplink component carrier may be configured to configure one serving cell. However, the serving cell is not configured with only one uplink component carrier.

The UE handing over from the serving cell to the

adjacent cells

800 and 810 in frequency is referred to as intra-frequency handover. On the other hand, the UE handover from the serving cell to the inter-frequency neighbor cells (815, 820, 825) is referred to as inter-frequency handover.

In order to transmit and receive packet data through a specific cell, the terminal must first complete configuration of a specific cell or CC. Herein, the configuration refers to a state in which system information required for data transmission and reception for a corresponding cell or CC is completed.

For example, the configuration may include an overall process of receiving common physical layer parameters, MAC layer parameters, or parameters required for a specific operation in the RRC layer. Accordingly, when the cell or CC which has been set up receives only signaling information indicating that packet data can be transmitted, the cell or CC can immediately transmit and receive packets.

On the other hand, the cell of the configuration complete state may exist in the activation (Activation) or deactivation (Deactivation) state. The reason for dividing the configuration state into an active state and an inactive state is to minimize the battery consumption of the UE by allowing the UE to monitor or receive the control channel (PDCCH) and the data channel (PDSCH) only in the active state. To do this.

Activation refers to the transmission or reception of traffic data being made or in a ready state. The UE may monitor or receive a control channel (PDCCH) and a data channel (PDSCH) of an activated cell in order to identify resources (which may be frequency, time, etc.) allocated thereto.

Deactivation means that transmission or reception of traffic data is impossible, and measurement or transmission of minimum information is possible. The terminal may receive system information (SI) required for packet reception from the deactivated cell. On the other hand, the terminal does not monitor or receive the control channel (PDCCH) and data channel (PDSCH) of the deactivated cell in order to check the resources (may be frequency, time, etc.) allocated to them.

Referring to FIG. 9, the main serving cell 905 is one serving cell providing security input and NAS mobility information in an RRC connection or re-establishment state. Means. According to the capabilities of the terminal, at least one cell may be configured to form a set of serving cells together with the main serving cell 905, and the at least one cell is called a secondary serving cell 920.

Therefore, the set of serving cells configured for one terminal may be configured by only one main serving cell 905 or may be configured by one main serving cell 905 and at least one secondary serving cell 920.

The

adjacent cells

900 and 910 in the frequency of the primary serving cell 905 and / or the

adjacent cells

915 and 925 in the frequency of the secondary serving cell 920 each belong to the same carrier frequency. In addition,

adjacent cells

930, 935, and 940 between frequencies of the main serving cell 905 and the secondary serving cell 920 belong to different carrier frequencies.

The downlink component carrier corresponding to the main serving cell 905 is called a downlink component carrier (DL PCC), and the uplink component carrier corresponding to the main serving cell 905 is called an uplink component carrier (UL PCC). In addition, in the downlink, the component carrier corresponding to the secondary serving cell 920 is called a downlink sub-component carrier (DL SCC), and in the uplink, the component carrier corresponding to the secondary serving cell 920 is uplink sub-element. This is called a carrier wave (UL SCC).

The PCC is a CC in which the terminal initially makes a connection (connection or RRC connection) with the terminal among several CCs. The PCC is a special CC that manages a connection (Connection or RRC Connection) for signaling regarding a plurality of CCs and manages UE context, which is connection information related to a terminal. In addition, the PCC is connected to the terminal and always exists in the active state in the RRC connected mode.

SCC is a CC assigned to the terminal in addition to the PCC, the SCC is an extended carrier (carrier) for the additional resource allocation other than the PCC and can be divided into an active or inactive state. The main serving cell 905 and the secondary serving cell 920 have the following characteristics.

First, the main serving cell 905 is used for transmission of the PUCCH.

Second, the main serving cell 905 is always activated, while the secondary serving cell 920 is a carrier that is activated / deactivated according to a specific condition.

Third, when the main serving cell 905 experiences RLF, RRC reconnection is triggered, but when the secondary serving cell 920 experiences RLF, RRC reconnection is triggered. It doesn't work.

Fourth, the main serving cell 905 may be changed by a security key change or a handover procedure accompanying a RACH (Random Access CHannel) procedure. However, in the case of MSG4 (contention resolution), only the PDCCH indicating the MSG4 should be transmitted through the main serving cell 905, and the MSG4 information may be transmitted through the main serving cell 905 or the secondary serving cell 920.

Fifth, non-access stratum (NAS) information is received through the main serving cell 905.

Sixth, the main serving cell 905 is always composed of a pair of DL PCC and UL PCC.

Seventh, a different CC may be set as the main serving cell 905 for each terminal.

Eighth, procedures such as reconfiguration, adding, and removal of the secondary serving cell 920 may be performed by the RRC layer. In addition to the new secondary serving cell 920, RRC signaling may be used to transmit system information of the dedicated secondary serving cell.

The technical spirit of the present invention with respect to the features of the primary serving cell 905 and the secondary serving cell 920 is not necessarily limited to the above description, which is merely an example and may include more examples.

When degradation occurs in a radio channel, the base station and the terminal may reset the radio connection to restore the radio connection. At this time, the main serving cell 905 is a serving cell in which a radio resource control channel is set, and resetting may be performed explicitly. However, the secondary serving cell 920 is burdened with unnecessary and complicated procedures such as component carrier removal, addition, and change by reconfiguration of the wireless connection after resetting the wireless connection. Furthermore, in the resetting of the main serving cell 905, there is no definition regarding whether to use the previously set secondary serving cells 920 as it is. A clear protocol is required between the terminal and the base station regarding a recovery procedure of the secondary serving cell 920 such as setting or resetting of the secondary serving cells 920.

First, the RRC connection reset and bearer information related thereto will be described in detail. Basically, RRC connection reestablishment is a procedure for restarting signaling radio bearer (hereinafter referred to as SRB), particularly SRB1 operation. There are three types of SRBs: SRB0, SRB1, and SRB2. SRB0 is used for RRC messages using a common control channel (CCCH) logical channel. Here, the downlink CCCH is used for transmitting information related to RRC connection establishment, connection reset, connection establishment rejection, and connection reset rejection, and the uplink CCCH is used for transmitting information related to RRC connection request and RRC connection reset request.

SRB1 is used for all RRC messages using a dedicated control channel (DCCH) logical channel. The RRC message may include some attached NAS message. It is also used for NAS messages before SRB2 setup. In addition, downlink NAS messages are used only for the accompanying procedures, such as bearer setup / change / release procedures. The uplink NAS message is only used to convey the initial NAS message during the RRC connection establishment. The downlink DCCH is used for transmitting information related to RRC connection reconfiguration and connection release. It is also used to transmit information related to security mode commands, counter checks, and handovers between heterogeneous networks. It is also used for transmitting downlink-related information, requesting terminal information, and transmitting UE capability enquiry-related information.

The uplink DCCH is used for transmitting information related to RRC connection reconfiguration completion, connection reconfiguration completion, and connection establishment completion. It is also used to transmit security mode setup complete or security mode setup failure, counter check response and proximity indication related information. And it is used for transmitting information related to uplink-related information transmission, measurement report (measurement report), terminal information response, UE capability information (UE capability information).

SRB2 is used for NAS messages using the DCCH logical channel. SRB2 has a lower priority than SRB1 and is configured by E-UTRAN after security activation. For example, after the RRC connection setup is completed, the security setup is completed and may be configured through an RRC connection reconfiguration procedure.

10 is a flowchart illustrating an RRC connection reconfiguration procedure according to an embodiment of the present invention. Here, in the multi-component carrier system, a plurality of CCs may be configured in the terminal. In addition, the terminal performs communication using the primary serving cell and the secondary serving cell.

Referring to FIG. 10, the terminal transmits an RRC connection reestablishment request message to the base station (S1000). The RRC connection reset request message includes SCell Configuration Information. The secondary serving cell configuration information is information indicating or specifying a secondary serving cell configured in the terminal and includes at least one of a cell index, a physical cell ID, and a center frequency value of the secondary serving cell. It includes. In particular, the secondary serving cell configuration information may be specified based on a time point before the RRC connection re-establishment procedure is started. As such, the terminal may specify what secondary serving cells are configured in the terminal at the time of the RLF generation through the secondary serving cell configuration information. The base station can know the secondary serving cells configured in the terminal at the time of the RLF by referring to the secondary serving cell configuration information in the RRC connection reconfiguration request message. The secondary serving cell configuration information is referred to when the base station performs addition, modification, removal, etc. of the secondary serving cell for the terminal.

As an example, when the secondary serving cell setting information includes a cell index, the secondary serving cell setting information is {1, 2, 5}. In this case, the secondary serving cell configuration information indicates that the secondary serving cells having

cell indexes

1, 2, and 5 are configured in the terminal before the RRC connection re-establishment procedure is started.

As another example, if the secondary serving cell configuration information includes a physical layer cell ID, the secondary serving cell configuration information is {4, 6}. In this case, the secondary serving cell configuration information indicates that the secondary serving cells having the physical layer cell IDs 4 and 6 are configured in the terminal before the RRC connection resetting procedure is started.

As another example, when the secondary serving cell configuration information includes a center frequency value of the secondary serving cell, the secondary serving cell configuration information is {100MHz, 110MHz}. In this case, the secondary serving cell configuration information indicates that a secondary serving cell having a center frequency of 100 MHz and 110 MHz, respectively, is configured in the terminal before the RRC connection resetting procedure is started.

Upon receiving the RRC connection reconfiguration request message, the base station determines whether RRC connection reconfiguration is possible, and if possible, transmits an RRC connection re-establishment message to the terminal for resetting the RRC connection (S1005). The RRC connection reset message basically contains information necessary to proceed with the following procedures. 1) a procedure for reconfiguring SRB1 and restarting data transmission specific to SRB1, and 2) reactivating AS security without changing the security algorithm.

In particular, the RRC connection reset message may include SCell Modification Information. The secondary serving cell change information is information indicating whether to release, change or maintain the secondary serving cell. The base station acquires the secondary serving cell change information with reference to the secondary serving cell setting information of the terminal. The UE can know the secondary serving cells to be released, changed or maintained through the secondary serving cell change information in the RRC connection reconfiguration message. If the base station determines that it is not necessary to change the secondary serving cell configuration of the terminal, the base station may not include the secondary serving cell change information in the RRC connection reconfiguration message. In this case, the terminal may maintain the existing secondary serving cell setting state.

After performing the RRC connection reset using the information in the RRC connection reestablishment message, the terminal transmits an RRC connection re-establishment complete message to the base station when all procedures are completed (S1010). As an example, the RRC connection reset complete message includes SCell Configuration Information. The secondary serving cell configuration information is information indicating or specifying a secondary serving cell configured in the terminal and includes at least one of a cell index, a physical cell ID, and a center frequency value of the secondary serving cell. It includes.

The secondary serving cell configuration information can be omitted so that unnecessary RRC procedures, for example, an RRC connection reconfiguration procedure, can be used to facilitate rapid RRC connection re-establishment and secondary serving cell configuration. Can be. In addition, due to the secondary serving cell setting information, the procedure for adding / changing / removing (releasing) the secondary serving cell may be clear.

As another example, the RRC connection reset complete message includes secondary serving cell change information. As another example, the RRC connection reset complete message includes both secondary serving cell configuration information and secondary serving cell change information.

As such, the secondary serving cell configuration information may be included in an RRC message exchanged between the terminal and the base station in the RRC connection reconfiguration procedure by piggybacking on the RRC connection reconfiguration procedure. For example, the secondary serving cell configuration information may be included in the RRC connection reset request message as in step S1000, or may be included in the RRC connection reset complete message as in step S1010. In the drawing, the secondary serving cell setting information is illustrated as being included in both the RRC connection reset request message and the RRC connection reset complete message. However, this indicates that the secondary serving cell setting information is one of an RRC connection reset request message and an RRC connection reset complete message. The secondary serving cell setting information is only to indicate that it can be included in any one message is not included in the other message. This is only a difference between whether secondary serving cell configuration information is transmitted at the start or end of the RRC connection reconfiguration procedure.

However, it may be included in both the RRC connection reset request message and the RRC connection reset complete message if necessary.

Referring to FIG. 11, when a terminal cannot maintain an RRC connection with a current main serving cell due to a cause, the terminal selects a cell for resetting an RRC connection for a predetermined time (S1100). The RRC connection reconfiguration procedure may be triggered in the following situations. 1) when a radio link failure (RFL) is detected, 2) a handover fails, 3) an acknowledgment failure indicator is transmitted from a lower layer, and 4) a connection reconfiguration has failed. .

When the above circumstances occur, the UE starts searching for a cell that may be determined to be suitable for attempting to reset the RRC connection during a time period in which the RRC connection can be reset. The cell may be a cell existing in the same network or may be a cell in a heterogeneous network supported by the terminal. The time period may be defined through a timer defined in the terminal (T311 in the case of LTE) and when the timer expires, the terminal changes the RRC mode to RRC_IDLE.

If the UE finds a cell suitable for initiating the RRC connection reconfiguration procedure, the UE configures UE identity information based on the appropriate cell and configures an RRC connection reconfiguration request message including secondary serving cell setting information. (S1105). However, all of the following conditions must be met for the RRC connection reset procedure to begin. 1) the UE shall be in RRC_CONNECTED mode, 2) AS (Access Stratum) security shall be activated, and 3) UE context shall be valid. On the other hand, if all of the above conditions are not satisfied, the terminal changes the RRC mode to RRC_IDLE.

The terminal transmits an RRC connection reset request message to the base station (S1110), and receives an RRC connection reset message from the base station in response thereto (S1115). The terminal proceeds with the RRC connection reconfiguration procedure based on the indication of the RRC connection reconfiguration message (S1120). When the RRC connection reconfiguration procedure is completed, the terminal transmits an RRC connection reestablishment complete message to the base station (S1125).

As an example, the RRC connection reset complete message includes SCell Configuration Information. The secondary serving cell configuration information indicates or specifies a secondary serving cell configured in the terminal, and includes a cell index, a physical cell ID, a center frequency value of the secondary serving cell, and a single base. It includes at least one of base station-specific cell index (eNB-specific cell index) information for distinguishing a plurality of domestic cells. The base station-specific cell index information is different from the cell index and is information allocated by the base station.

Here, the cell index is information that is set so that any base station indicates a serving cell. The cell index is a variable value depending on the serving cells configured in each terminal, which is an independent value for each terminal. That is, a different cell index may be set for each terminal for one serving cell that is physically identical by the base station.

On the other hand, the physical layer cell ID (Physical Cell ID) is information that is set to indicate the serving cell in the LTE system. That is, a value for indicating the serving cells that can be set to each of the plurality of base stations, which is fixedly set in the system configuration.

In addition, the base station-specific cell index (eNB-specific cell index) information is information that any base station is configured to indicate the serving cell, which is a value that varies depending on the serving cells configured in each base station, which is independent value for each base station to be. That is, the same cell index may be set for each terminal for one serving cell that is physically identical by the base station.

The eNB-specific cell index (eNB-specific cell index) information may be transmitted to the terminal through an RRC reconfiguration procedure or may be transmitted to the terminal through a broadcasting channel, in particular, a system information block 2 (SIB2).

Referring to FIG. 12, steps S1200 to S1215 are the same as steps S1100 to S1115. 12 differs from FIG. 11 in that the UE further includes a feature (step S1220) for determining whether the secondary serving cell change information is included in the RRC connection re-establishment message.

In step S1220, the terminal determines whether the RRC connection reconfiguration message includes secondary serving cell change information. If the RRC connection reconfiguration message includes the secondary serving cell change information, the terminal performs the operation of adding, changing or removing the secondary serving cell according to the contents of the secondary serving cell change information (S1225). If, on the other hand, the RRC connection reconfiguration message does not include secondary serving cell change information, the terminal proceeds to the general RRC connection reconfiguration procedure (S1230). When the RRC connection reset procedure is completed, the terminal transmits an RRC connection reset complete message to the base station (S1235). At this time, the RRC connection reset complete message may include a secondary serving cell configuration information (SCell Configuration Information). The secondary serving cell configuration information is information indicating or specifying a secondary serving cell configured in the terminal, and includes a cell index, a physical cell ID, a center frequency value of the secondary serving cell, and a base station specialized. It includes at least one of the cell-specific (eNB-specific cell index) information.

Referring to FIG. 13, the base station receives an RRC connection reconfiguration request message including secondary serving cell configuration information from the terminal (S1300). The secondary serving cell configuration information is information indicating or specifying a secondary serving cell configured in the terminal and includes at least one of a cell index, a physical layer cell ID, and a center frequency value of the secondary serving cell. The base station determines whether the terminal can perform the RRC connection reconfiguration procedure on the basis of the RRC connection reconfiguration request message (S1305). If it is determined that the terminal cannot perform the RRC connection reconfiguration procedure, the base station transmits an RRC connection reconfiguration rejection message to the terminal.

If it is determined that the UE can perform the RRC connection resetting procedure, the base station changes the configuration of the secondary serving cell in consideration of the secondary serving cell configuration information received from the terminal, the cause of resetting, and whether the secondary serving cell is supported by the base station. Identify the available secondary serving cell without (S1310). If the secondary serving cell configuration information is not included in the RRC connection reconfiguration request message received from the terminal, the base station may remove all secondary serving cells of the terminal.

The base station transmits an RRC connection reset message to the terminal (S1315), and receives an RRC connection reset complete message from the terminal (S1320). As an example, the RRC connection reset complete message includes SCell Configuration Information. The secondary serving cell configuration information is information indicating or specifying a secondary serving cell configured in the terminal, and includes a cell index, a physical cell ID, a center frequency value of the secondary serving cell, and a base station specialized. It includes at least one of the cell-specific (eNB-specific cell index) information. As another example, the RRC connection reset complete message includes secondary serving cell change information. As another example, the RRC connection reset complete message includes both secondary serving cell configuration information and secondary serving cell change information.

Referring to FIG. 14, the base station receives an RRC connection reconfiguration request message including secondary serving cell configuration information from the terminal (S1400). The secondary serving cell configuration information is information indicating or specifying a secondary serving cell configured in the terminal and includes at least one of a cell index, a physical layer cell ID, and a center frequency value of the secondary serving cell.

The base station determines whether the terminal can perform the RRC connection reconfiguration procedure based on the RRC connection reconfiguration request message (S1405). If it is determined that the terminal cannot perform the RRC connection reconfiguration procedure, the base station transmits an RRC connection reconfiguration rejection message to the terminal.

If it is determined that the UE can perform the RRC connection resetting procedure, the base station changes the configuration of the secondary serving cell in consideration of the secondary serving cell configuration information received from the terminal, the cause of resetting, and whether the secondary serving cell is supported by the base station. Identify the available secondary serving cell without (S1410).

When a change is required for the setting of the secondary serving cell, the base station configures secondary serving cell change information indicating change, removal, addition, etc. of at least one secondary serving cell (S1415). If a change is not required for the setting of the secondary serving cell, the base station does not configure additional secondary serving cell change information.

The base station transmits an RRC connection reset message including secondary serving cell change information to the terminal (S1420), and receives an RRC connection reset complete message from the terminal (S1425).

Hereinafter, information included in the RRC connection reconfiguration request message, specifically, secondary serving cell configuration information, UE-identity information, reestablishment cause information, and the like will be described in more detail.

1. Terminal specific information

Terminal specific information includes three items of Table 1.

Table 1

Cell-Radio Network Temporary Identifier

Physical Cell ID for Primary Serving Cell

Encryption Information (short MAC-I)

The encryption information is composed of 16 bits using an integrity protection key (K _RRCint ) of the RRC signaling and an integrity security algorithm.

The UE-specific information is configured with a value used in a source cell (serving cell immediately before handover) when handover to a network or a heterogeneous network fails. In other cases, the UE specific information is configured with a value used in a cell currently undergoing RRC connection reconfiguration.

2. Reset Cause Information

Reset cause information is specified by any one of the three items in the following Table 2.

In-device coexistence (IDC) interference refers to interference caused by a wireless communication system other than LTE in the terminal. Therefore, 'failure due to IDC' means that a problem occurs in the radio link of the LTE system due to the IDC interference.

TABLE 2

Reconfiguration failure

Handover failure

In-device interference failure

Other failures

3. SCell Configuration Information (SCell CI)

The secondary serving cell configuration information is information indicating or specifying a secondary serving cell configured in the terminal, and includes at least one of a cell index, a physical layer cell ID, a center frequency value of the secondary serving cell, and base station-specific cell index information. It includes one. The cell index, physical layer cell ID, and center frequency values configuring the secondary serving cell configuration information may be information that both the UE and the base station know. In this case, when the UE or the base station knows any one value, the terminal or the base station can know all the other two values. Therefore, even if only one of the cell index, the physical layer cell ID, and the center frequency value is included in the RRC connection reset request message or the RRC connection reset complete message, the receiving base station can also know the remaining two pieces of information.

Table 3 is an example of secondary serving cell configuration information when the maximum number of CCs supported by the system is eight.

TABLE 3

SCell-CI :: = SEQUENCE {cell-Index BIT STRING (SIZE 8),}

Referring to Table 3, the secondary serving cell configuration information includes only the cell index of the secondary serving cell, and each position of the BIT STRING 8 bits corresponds to one secondary serving cell. Therefore, the secondary serving cell or CC index may be allocated from 0 to 7 times. Of course, since the maximum number of CCs is 8, the cell index of the secondary serving cell may be allocated from 0 to (m-1) times when the maximum number of CCs supported by the system is m. One bit represents 1 or 0, which indicates whether the secondary serving cell is configured or not. Least Significant Bit (LSB) means cell index = 0. If the cell index of the main serving cell (PCell) is always set to 0, the LSB is always set to 0, or the length of the BIT STRING is set to m-1, and the LSB in the BIT STRING means the cell index = 1. You can also do that.

Table 4 is another example of secondary serving cell setting information.

Table 4

SCell-Info :: = SEQUENCE (SIZE (1..maxSCell)) of SCell-CISCell-CI :: = SEQUENCE {physCellId PhysCellId,}

Referring to Table 4, the secondary serving cell configuration information includes only the physical layer cell ID (physCellID) of the secondary serving cell.

Table 5 is another example of secondary serving cell configuration information.

Table 5

SCell-Information :: = SEQUENCE (SIZE (1..maxSCell)) of SCellInfoSCellInfo :: = SEQUENCE {carrierFreq CarrierFreq,}

Referring to Table 5, the secondary serving cell configuration information includes only the center frequency value (carrierFreq) of the secondary serving cell.

Table 6 is another example of secondary serving cell configuration information.

Table 6

SCell-CI :: = SEQUENCE {cell-Index BIT STRING (SIZE 8), PCI-Information :: = SEQUENCE (SIZE (1..maxSCell)) of PCIInfo PCIInfo :: = SEQUENCE {physCellId PhysCellId,} CaFreq-Information: : = SEQUENCE (SIZE (1..maxSCell)) of CaFreqInfo CaFreqInfo :: = SEQUENCE {carrierFreq CarrierFreq,}}

Referring to Table 6, the secondary serving cell configuration information includes all of a cell index, a physical layer cell ID, and a center frequency value. A physical channel cell ID and a center frequency value for a secondary serving cell corresponding to a position set to '1' in a cell index field (cell-Index) are set. On the other hand, the physical channel cell ID and the center frequency value for the secondary serving cell corresponding to the position set to '0' in the cell index field are set to 'NULL' or a value meaning meaningless. For example, when the BIT STRING of the cell index is 4 bits, the BIT STRING is the physical channel cell ID field corresponding to the one cell index having the bit value of 0 and the center frequency when the bit index is {1, 0, 1, 1}. The value field is represented by 'NULL', and the physical channel cell ID field and the center frequency value field corresponding to three cell indexes having a bit value of 1 are set to a specific value.

As an example, the secondary serving cell configuration information may be present in the RRC connection reconfiguration request message or the RRC connection reconfiguration complete message independently of the UE-identity information.

Table 7 shows a part of an RRC connection reset request message according to an embodiment of the present invention.

TABLE 7

SCell-CI :: = SEQUENCE (SIZE (1..maxSCell)) of SCellInfoSCellInfo :: = SEQUENCE {cell-Index Cell-Index, physCellId PhysCellId, carrierFreq CarrierFreq, eNBspecificCell-index ENBCell-index}

Referring to Table 7, the RRC connection reset request message or the RRC connection reset complete message is a secondary serving cell configuration information, and includes cell index, physical layer cell ID, center frequency value, and base station-specific cell index information. Include.

Table 8 shows a part of an RRC connection reset request message according to another example of the present invention.

Table 8

SCell-CI :: = SEQUENCE (SIZE (1..maxSCell)) of SCellInfoSCellInfo :: = SEQUENCE {cell-Index Cell-Index, eNBspecificCell-index ENBCell-index}

Referring to Table 8, the RRC connection reconfiguration request message or the RRC connection reconfiguration complete message includes cell index and eNB-specific cell index information as secondary serving cell configuration information.

Here, the cell index is information used when any base station can know the terminal requesting the RRC connection reconfiguration.

The eNB-specific cell index information is information used when a base station does not know a terminal requiring RRC connection reconfiguration.

Accordingly, the terminal may select and transmit only one of cell index and eNB-specific cell index information.

Table 9 shows a part of an RRC connection reset request message according to another embodiment of the present invention.

Table 9

ReestabUE-Identity :: = SEQUENCE {c-RNTI C-RNTI, physCellId PhysCellId, shortMAC-I ShortMAC-I, SCell-CI SCell-CI}

Referring to Table 9, the terminal specific information (ReestabUE-Identity) for resetting includes the secondary serving cell configuration information (SCell-CI).

As another example, the secondary serving cell configuration information may be absorbed / included in the terminal specific information.

Table 10 is a part of the RRC connection reset request message or RRC connection reset complete message according to another embodiment of the present invention.

Table 10

ReestabUE-Identity :: = SEQUENCE {c-RNTI C-RNTI, physCellId PhysCellId, shortMAC-I ShortMAC-I} SCell-CI :: = SEQUENCE {cell-Index BIT STRING (SIZE (8))}

Referring to Table 10, the secondary serving cell configuration information (SCell-CI) is separated from the terminal specific information (ReestabUE-Identity) for resetting in the RRC connection reconfiguration request message or RRC connection reconfiguration complete message. In particular, the secondary serving cell configuration information includes only a cell index.

15 illustrates a scenario in which a setting of a serving cell is changed according to an embodiment of the present invention. This is the case where both the main serving cell and the secondary serving cell are changed or not.

Referring to FIG. 15, as an example, consider a case in which a radio link failure (RLF) occurs while the terminal 1500 moves from point A to point B. At the point A, the primary serving cell of the terminal 1500 is configured with an uplink / downlink CC of the P1 band, the secondary serving cell of the terminal 1500 is configured with an uplink / downlink CC of the S1 band.

When the RLF occurs, the terminal 1500 searches for a cell for RRC connection reestablishment. At this time, if the terminal 1500 has all the requirements to perform the RRC connection reset while moving to the point B, and selected a cell consisting of the uplink / downlink CC of the P2 band as a cell suitable for the RRC connection reset, 1500 performs an RRC connection reconfiguration procedure through a cell of the P2 band. This procedure involves the procedure of changing the main serving cell from the P1 band to the P2 band.

Meanwhile, the terminal 1500 includes at least one of a cell index, a physical channel cell ID, a center frequency value, and base station-specific cell index information of the secondary serving cell S1 set at the time of the RLF generation. The cell configuration information may be included in the RRC connection reset request message or the RRC connection reset complete message and transmitted to the base station 1510. Since the terminal 1500 has moved to the point B, which is a point where all of the secondary serving cells that can be set at the point A are not supported, the base station 1510 performs a removal procedure for all previously set secondary serving cells. If necessary, additional procedures can be simultaneously performed for the secondary serving cell that can be configured at point B.

As another example, consider a case where a radio link failure (RLF) occurs while the terminal 1505 moves from point C to point D. At point C, the terminal 1505 is configured to use a cell configured as an uplink / downlink CC of the P3 band as a main serving cell, and configure a cell configured as an uplink / downlink CC of the S3 band as a secondary serving cell. I use it. If the terminal 1505 proceeds to reset the RRC connection using the P3 band as the main serving cell at the point D (or point C) after the RLF occurs at the point C, the terminal 1505 and the base station 1510 are configured to be negative. No change (or removal) to the serving cell is necessary.

However, if the terminal 1505 changes the SRC band to the main serving cell at point D and proceeds with the RRC connection reconfiguration, a change to the secondary serving cell should be applied. Accordingly, the UE 1505 includes at least one of a cell index, a physical channel cell ID, a center frequency value, and base station-specific cell index information of the secondary serving cell S3 set at the time of the RLF generation. The cell configuration information may be included in the RRC connection reconfiguration request message and transmitted to the base station 1510, or may be included in the RRC connection reconfiguration complete message used when the RRC connection reconfiguration procedure is completed and transmitted to the base station 1510. At this time, the base station 1510 proceeds with the removal procedure for S3 as a secondary serving cell and does not remove other secondary serving cells. This is because the previously set secondary serving cell S3 is set as the primary serving cell. The base station 1510 may simultaneously perform a change procedure for the secondary serving cells that are not removed and an additional procedure for the secondary serving cell if necessary.

16 illustrates a scenario in which a setting of a serving cell is changed according to another example of the present invention. This is a case where the main serving cell is changed and the secondary serving cell is not changed.

Referring to FIG. 16, a radio link failure (RLF) occurs while the terminal 1600 moves from point A to point B. At point A, the main serving cell of the terminal 1600 is configured of an uplink / downlink CC of the P1 band, and the secondary serving cell of the terminal 1600 is configured of an uplink / downlink CC of the S2 band.

When the RLF occurs, the terminal 1600 searches for a cell for RRC connection reestablishment. At this time, if the terminal 1600 has all the requirements to perform the RRC connection reset while moving to the point B, and selected a cell consisting of the uplink / downlink CC of the P2 band as a cell suitable for resetting the RRC connection, 1600 performs an RRC connection reconfiguration procedure through a cell of the P2 band. This procedure involves the procedure of changing the main serving cell from the P1 band to the P2 band. On the other hand, at branch B, the secondary serving cell is the same as that at branch A as S2. Therefore, in this case, the secondary serving cell does not have to be changed.

However, if the terminal 1600 changes the S2 band to the main serving cell at point B and proceeds with the RRC connection reconfiguration, a change to the secondary serving cell should be applied. Accordingly, the terminal 1600 includes at least one of a cell index, a physical channel cell ID, a center frequency value, and base station-specific cell index information of the secondary serving cell S2 set at the time of the RLF generation. The cell configuration information may be included in the RRC connection reset request message or the RRC connection reset complete message and transmitted to the base station 1605. At this time, the base station 1605 proceeds with the removal procedure for S2 serving as a secondary serving cell and does not remove other secondary serving cells. This is because the previously set secondary serving cell S2 is changed to the primary serving cell. The base station 1605 may simultaneously perform a change procedure and additional procedures of secondary serving cells that are not removed if necessary.

17 illustrates a scenario in which a setting of a serving cell is changed according to another example of the present invention. This is the case in which the main serving cell is not changed and only the secondary serving cell is changed.

Referring to FIG. 17, a radio link failure (RLF) occurs while the terminal 1700 moves from point A to point B. At point A, the primary serving cell of the terminal 1700 is configured with an uplink / downlink CC of the P1 band, and the secondary serving cell of the terminal 1700 is configured with an uplink / downlink CC of the S2 band.

When the RLF occurs, the terminal 1700 searches for a cell to re-establish the RRC connection. At this time, if the terminal 1700 has all the requirements to perform the RRC connection reset while moving to the point B, and selected a cell consisting of the uplink / downlink CC of the existing P1 band as a cell suitable for the RRC connection reset The terminal 1700 performs an RRC connection reconfiguration procedure through a cell of an existing P1 band. On the other hand, since the secondary serving cell is S1 at point B, it is different from the secondary serving cell at point A. Therefore, in this case, the secondary serving cell must be changed.

To this end, the UE 1700 includes at least one of a cell index, a physical channel cell ID, a center frequency value, and base station-specific cell index information of the secondary serving cell S2 set at the time of the RLF generation. The cell configuration information may be included in the RRC connection reset request message or the RRC connection reset complete message and transmitted to the base station. At this time, the base station 1705 may proceed with the removal procedure for not only S2 serving as a secondary serving cell but other unsupportable secondary serving cells, and other secondary serving cells may not be removed. The base station 1705 may simultaneously proceed with the additional procedure of the secondary serving cell if necessary.

As described with reference to FIG. 15 to FIG. 17, when the secondary serving cell information in the carrier aggregation environment in which the current RRC connection is reset and the carrier aggregation environment before the RRC connection resetting procedure are different, the RRC connection resetting procedure is performed. By using the secondary serving cell setting information, the configuration change can be performed by adding / modifying / removing the secondary serving cell previously set between the terminal and the base station.

Referring to FIG. 18, the terminal 1800 includes a cell selector 1805, a secondary serving cell configuration information configuration unit 1810, an uplink message transmitter 1815, and a downlink message receiver 1820.

The cell selector 1805 selects a cell for establishment or reestablishment of an RRC connection. The RRC connection reconfiguration procedure is performed when 1) a radio link failure (RLF) is detected, 2) a handover fails, 3) an acknowledgment failure indicator is sent from a lower layer, and 4) a connection reconfiguration has failed. Can be started. When the above situations occur, the cell selector 1805 starts searching for a cell that may be determined to be suitable for attempting to reset the RRC connection during a time period in which the RRC connection may be reset. The cell may be a cell existing in the same network or may be a cell in a heterogeneous network supported by the terminal. The time period may be defined through a timer (T311 in the case of LTE) defined in the terminal. When the timer expires, the cell selector 1805 changes the mode of the terminal 1800 to RRC_IDLE. If the cell selector 1805 finds a cell suitable for starting the radio connection resetting procedure, the cell selector 1805 configures UE identity information based on the appropriate cell.

The secondary serving cell setting information configuring unit 1810 configures secondary serving cell setting information for specifying at least one secondary serving cell set in the terminal 1800. The secondary serving cell configuration information is information indicating or specifying a secondary serving cell configured in the terminal, and includes a cell index, a physical cell ID, a center frequency value of the secondary serving cell, and a base station specific cell index ( At least one of eNB-specific cell index) information. In particular, the secondary serving cell setting information configuration unit 1810 may configure the secondary serving cell setting information based on a time point before the RRC connection resetting procedure is started. As described above, the secondary serving cell setting information configuration unit 1810 may specify what secondary serving cells are set in the terminal at the time of the RLF generation through the secondary serving cell setting information. Secondary serving cell setting information may be defined as shown in Tables 3 to 10 above.

The uplink message transmitter 1815 transmits an RRC connection reset request message or an RRC connection reset complete message including secondary serving cell configuration information to the base station 1850. As an example, the RRC connection reset request message or the RRC connection reset complete message may include UE-specific information, and the secondary serving cell configuration information may be transmitted in a form included in UE-specific information. As another example, the RRC connection reset request message or the RRC connection reset complete message may include terminal unique information, and the secondary serving cell configuration information may be transmitted in a form that is independent of the terminal unique information.

The downlink message receiver 1820 receives an RRC connection reconfiguration message including the secondary serving cell change information from the base station 1850.

The base station 1850 includes an uplink message receiver 1855, a secondary serving cell change information configuration unit 1860, and a downlink message transmitter 1876.

The uplink message receiving unit 1855 receives the RRC connection reset request message or the RRC connection reset complete message from the terminal 1800 and extracts the secondary serving cell configuration information included in the RRC connection reset request message or the RRC connection reset complete message. . By the extraction, the uplink message receiving unit 1855 includes a cell index, a physical layer cell ID, a center frequency value of a secondary serving cell, and base station-specific cell index information. Acquire at least one and deliver them to the secondary serving cell change information configuration unit 1860.

The secondary serving cell change information configuring unit 1860 may be configured based on at least one of a cell index, a physical layer cell ID, a center frequency value of the secondary serving cell, and base station-specific cell index information received from the uplink message receiver 1855. Check at least one secondary serving cell configured at 1800 and change the setting of at least one secondary serving cell configured at the terminal 1800 according to various scenarios as shown in FIGS. 15 to 17 (that is, remove or remove a secondary serving cell). Change or add) the secondary serving cell change information. The secondary serving cell change information includes information on adding / changing / removing a secondary serving cell.

The downlink message transmitter 1876 transmits an RRC connection reconfiguration message including the secondary serving cell change information to the terminal 1800.

All of the above functions may be performed by a processor such as a microprocessor, a controller, a microcontroller, an application specific integrated circuit (ASIC), or the like according to software or program code coded to perform the function. The design, development and implementation of the code will be apparent to those skilled in the art based on the description of the present invention.

Although the present invention has been described above with reference to the embodiments, it will be apparent to those skilled in the art that the present invention may be modified and changed in various ways without departing from the spirit and scope of the present invention. I can understand. Therefore, the present invention is not limited to the above-described embodiment, and the present invention will include all embodiments within the scope of the following claims.

Claims

In the terminal for performing a radio connection reset in a multi-component carrier system,

A cell selector for selecting a cell for resetting the wireless connection when the wireless connection fails;

A secondary serving cell setting information configuration unit configured to configure secondary serving cell setting information for specifying at least one secondary serving cell set in the terminal;

A message transmitter for transmitting a radio connection reset request message for requesting the radio link reset procedure and a radio link reset complete message indicating completion of the radio link reset procedure to the base station through the selected cell; And

Including a message receiving unit for receiving a radio connection reset message in response to the radio connection reset request message,

The secondary serving cell setting information may be included in any one of the radio connection reset request message and the radio connection reset complete message.
The method of claim 1,

The secondary serving cell configuration information configuration unit may perform at least one of cell index, physical channel cell ID (IDentifier), center frequency value, and eNB-specific cell index information of the at least one secondary serving cell. Configure cell configuration information,

The cell index is an index used when the base station knows that the terminal is a terminal for requesting RRC connection reconfiguration,

The base station-specific cell index, characterized in that the base station is used when the terminal does not know that the terminal to request the RRC connection reset, characterized in that the terminal.
The method of claim 2,

The cell index, characterized in that having the number of bits as the number of maximum secondary serving cells that can be supported by the system.
The method of claim 3, wherein

If the bit of the cell index is 1, the secondary serving cell corresponding to the bit is set in the terminal. If the bit of the cell index is 0, the secondary serving cell corresponding to the bit is not set in the terminal. , Terminal.
The method of claim 4, wherein

If the bit of the cell index is 0, the physical channel cell ID or the center frequency value for the secondary serving cell corresponding to the bit is set to 'NULL'.
The method of claim 1,

The radio connection is a terminal, characterized in that the RRC connection performed in the Radio Resource Control (RRC) layer.
The method of claim 1,

The secondary serving cell configuration information configuration unit, characterized in that configured to include the secondary serving cell configuration information in the UE (id_idendity) information.
The method of claim 1,

The secondary serving cell setting information configuration unit, characterized in that for configuring the secondary serving cell setting information separately from the unique information of the terminal.
In the method of performing a radio connection reset by the terminal in a multi-component carrier system,

Selecting a cell for re-establishing the wireless connection when the wireless connection fails;

Configuring secondary serving cell setting information for specifying at least one secondary serving cell set in the terminal;

Transmitting a radio connection reset request message to the base station through the selected cell requesting the radio link reset;

Receiving a radio reset message in response to the radio link reset request message; And

Transmitting to the base station through the selected cell a radio connection reset complete message indicating completion of the radio connection reset procedure;

The secondary serving cell setting information may be included in any one of the radio connection reset request message and the radio connection reset complete message.
A base station performing radio connection reconfiguration in a multi-component carrier system,

An uplink message receiver configured to receive a radio connection reset request message requesting the reset of a radio connection or a radio connection reset complete message indicating completion of a radio connection reset procedure from a terminal through a primary serving cell;

The at least one secondary serving cell is removed from the wireless connection reset request message and the wireless connection reset complete message by referring to the secondary serving cell configuration information that specifies at least one secondary serving cell set in the terminal. Or a secondary serving cell change information configuration unit configured to determine whether to change and to configure secondary serving cell change information indicating addition, removal or change of the secondary serving cell based on the determination; And

And a downlink message transmitter for transmitting a radio connection reset message including the secondary serving cell change information to the terminal in response to the radio connection reset request message.
The method of claim 10,

The secondary serving cell configuration information includes at least one of a cell index, a physical channel cell ID, a center frequency value, and base station-specific cell index information of the at least one secondary serving cell,

The cell index is an index used when the base station knows that the terminal is a terminal for requesting RRC connection reconfiguration,

The base station specific cell index, the base station, characterized in that the index is used when the terminal is not known that the terminal requesting the RRC connection reset.
The method of claim 10,

The at least one secondary serving cell is characterized by consisting of a downlink component carrier and an uplink component carrier, the base station.
A method for performing radio connection reset by a base station in a multi-element carrier system,

Receiving a wireless connection reset request message requesting the resetting of the wireless connection or a wireless connection resetting complete message indicating that the resetting of the wireless connection is completed from the terminal through a main serving cell when the wireless connection fails; And

The at least one secondary serving cell is included in at least one of the radio connection reset request message and the radio connection reset complete message and based on the secondary serving cell configuration information specifying at least one secondary serving cell set in the terminal. Or transmitting to the terminal a radio connection reconfiguration message including the secondary serving cell change information indicating whether to change.