KR20130049132A - Apparatus and method for performing uplink synchronization in multiple component carrier system - Google Patents

Abstract

The present invention relates to an apparatus and method for performing uplink synchronization in a multi-component carrier system.
The present specification comprises the steps of receiving secondary cell configuration information including information used to configure at least one secondary serving cell in the terminal from the base station, an activation indicator for instructing activation or deactivation of the secondary serving cell configured in the terminal; Receiving a MAC message including configuration information on a time alignment group, which is a set of secondary serving cells having the same uplink time alignment value, from the base station, and according to an indication of the activation indicator, Disclosed is a method of performing uplink synchronization by a terminal in a multi-component carrier system including setting a state to be activated or deactivated.
According to the present invention, the base station transmits the time alignment group configuration information and the activation indicator to the terminal at the same time so that the terminal can quickly receive a random access start indicator, and also can secure uplink synchronization in the secondary serving cell quickly. have.

Description

Apparatus and method for performing uplink synchronization in a multi-component carrier system {APPARATUS AND METHOD FOR PERFORMING UPLINK SYNCHRONIZATION IN MULTIPLE COMPONENT CARRIER SYSTEM}

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

In a wireless communication environment, a propagation delay is propagated while a transmitter propagates and propagates in a receiver. Therefore, even if the transmitter and the receiver both know the time at which the radio wave is propagated correctly, the arrival time of the signal to the receiver is influenced by the transmission / reception period distance and the surrounding propagation environment. If the receiver does not know exactly when the signal transmitted by the transmitter is received, it will receive the distorted signal even if it fails to receive or receive the signal.

Therefore, in a wireless communication system, synchronization between a base station and a terminal must be made in advance in order to receive an information signal regardless of downlink and uplink. Types of synchronization include frame synchronization, information symbol synchronization, and sampling period synchronization. Sampling period synchronization is the most basic motivation to distinguish physical signals.

The downlink synchronization acquisition is performed in the UE based on the signal of the base station. The base station transmits a mutually agreed specific signal for facilitating downlink synchronization acquisition at the terminal. The terminal must be able to accurately identify the time at which a particular signal sent from the base station is transmitted. In case of downlink, since one base station simultaneously transmits the same synchronization signal to a plurality of terminals, each of the terminals can acquire synchronization independently of each other.

In case of uplink, the base station receives signals transmitted from a plurality of terminals. When the distance between each terminal and the base station is different, signals received by each base station have different transmission delay times. When uplink information is transmitted on the basis of the acquired downlink synchronization, Is received at the corresponding base station. In this case, the base station can not acquire synchronization based on any one of the terminals. This is also the case in a multi-carrier system supporting a plurality of component carriers. Carrier aggregation is a technique for efficiently using fragmented small bands so that a plurality of bands that are physically non-continuous in the frequency domain can be combined to have an effect such as using a logically large band. It is to.

Since each component carrier has a different frequency, the delay time may be different for each component carrier even in the same environment. Therefore, the base station must adjust uplink synchronization for each component carrier.

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

Another object of the present invention is to provide an apparatus and method for transmitting an MAC message including an activation indicator indicating activation / deactivation of a serving cell and configuration information of a time alignment group.

Another object of the present invention is to provide an apparatus and method for transmitting a logical channel identification field for identifying an MAC control element including an activation indicator indicating activation / deactivation and configuration information of a time alignment group.

According to an aspect of the present invention, in a method of performing uplink synchronization by a terminal in a multi-component carrier system, secondary serving cell configuration information including information used to configure at least one secondary serving cell in a terminal Receiving from the base station, a timing alignment group (timing alignment group) which is a set of secondary serving cells having an activation indicator indicating activation or deactivation of the secondary serving cell configured in the terminal and the same uplink timing alignment value (timing alignment value) Receiving a medium access control (MAC) message including configuration information on a TAG from the base station, and activating or deactivating a state of a secondary serving cell configured in the terminal according to an indication of the activation indicator It includes the step of setting.

Another aspect of the present invention provides a method for performing uplink synchronization by a base station in a multi-component carrier system, the method comprising: transmitting secondary serving cell configuration information including information used to configure at least one secondary serving cell to a terminal; And a MAC message including an activation indicator indicating activation or deactivation of a secondary serving cell configured in the terminal and configuration information regarding a time alignment group, which is a set of secondary serving cells having the same uplink time alignment value, to the terminal. Transmitting.

According to another aspect of the present invention, in a terminal performing uplink synchronization in a multi-component carrier system, secondary cell configuration information and MAC messages including information used to configure at least one secondary serving cell in the terminal are transmitted from a base station. An RRC message processor configured to receive a terminal receiving unit and configure a secondary serving cell in the terminal based on the secondary serving cell configuration information, and set the state of the secondary serving cell configured in the terminal to be activated or deactivated according to the indication of the activation indicator. A MAC message processing unit for obtaining configuration information regarding a time alignment group which is a set of secondary serving cells having the same uplink time alignment value and an activation indicator indicating activation or deactivation of a secondary serving cell configured in the terminal from the MAC message; And reconfiguring the RRC connection in response to the reception of the secondary serving cell configuration information. The message includes the terminal transmission part for transmitting to the base station.

Another aspect of the present invention is a base station for performing uplink synchronization in a multi-component carrier system, the base station used to determine at least one secondary serving cell to be configured in the terminal, and configured to configure the determined secondary serving cell in the terminal Generating a MAC message including a cell configuration unit for generating serving cell configuration information, an activation indicator for activating or deactivating a secondary serving cell configured in the terminal, and configuration information about a time alignment group specifically configured for the terminal. TAG processing unit, and the base station transmitting unit for transmitting the MAC message to the terminal.

Since the base station transmits the time alignment group configuration information and the activation indicator to the terminal at the same time, the terminal can quickly receive the random access start indicator, and can also secure uplink synchronization in the corresponding secondary serving cell quickly.

1 shows a wireless communication system to which the present invention is applied.
2 shows an example of a protocol structure for supporting multiple carriers to which the present invention is applied.
3 shows an example of a frame structure for multi-carrier operation to which the present invention is applied.
4 shows a linkage between a downlink component carrier and an uplink component carrier in a multi-carrier system to which the present invention is applied.
5 is a flowchart illustrating a method of performing uplink synchronization according to an embodiment of the present invention.
6 shows a structure of a MAC message according to an embodiment of the present invention.
7 is a block diagram showing the structure of a MAC control element according to an embodiment of the present invention.
8 is a block diagram illustrating a structure of a MAC control element according to another example of the present invention.
9 is a block diagram showing the structure of a MAC control element according to another example of the present invention.
10 shows a structure of a MAC message according to another example of the present invention.
11 shows a structure of a MAC message according to another example of the present invention.
12 illustrates a structure of a MAC control element related to activation and TAG configuration according to an embodiment of the present invention.
13 shows a structure of a MAC control element related to TAG configuration according to an embodiment of the present invention.
14 shows a structure of a MAC control element related to TAG configuration according to another embodiment of the present invention.
15 shows a structure of a MAC control element related to TAG configuration according to another embodiment of the present invention.
16 shows a structure of a MAC control element related to TAG configuration according to another embodiment of the present invention.
17 is a flowchart illustrating a method of performing uplink synchronization of a terminal according to an embodiment of the present invention.
18 is a flowchart illustrating a method of performing uplink synchronization by a base station according to an embodiment of the present invention.
19A is a flowchart illustrating a method of transmitting an RRC message including information about a time alignment group according to the present invention.
19B is a block diagram illustrating a terminal and a base station performing a random access procedure according to an embodiment of the present invention.

Hereinafter, some embodiments will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used to refer to the same components as much as possible even if displayed on different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.

In describing the components of the present specification, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; may be "connected," "coupled," or "connected. &Quot;

In addition, the present invention will be described with respect to a wireless communication network. The work performed in the wireless communication network may be performed in a process of controlling a network and transmitting data by a system (e.g., a base station) Work can be done at a terminal connected to the network.

1 shows a wireless communication system to which the present invention is applied.

Referring to FIG. 1, a wireless communication system 10 is widely deployed to provide various communication services such as voice, packet data, and the like. The wireless communication system 10 includes at least one base station 11 (BS). Each base station 11 provides communication services to specific cells (15a, 15b, 15c). The cell may again be divided into multiple regions (referred to as sectors).

A mobile station (MS) 12 may be fixed or mobile and may be a user equipment (UE), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, (personal digital assistant), a wireless modem, a handheld device, and the like. The base station 11 may be called by other terms such as an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, a femto base station, a home node B, . The cell should be interpreted in a generic sense to indicate a partial area covered by the base station 11 and is meant to cover various coverage areas such as a megacell, a macro cell, a microcell, a picocell, and a femtocell.

Hereinafter, downlink refers to communication from the base station 11 to the terminal 12, and uplink refers to communication from the terminal 12 to the base station 11. In the downlink, the transmitter may be part of the base station 11, and the receiver may be part of the terminal 12. In the uplink, the transmitter may be part of the terminal 12, and the receiver may be part of the base station 11. There are no restrictions on multiple access schemes applied to wireless communication systems. (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier-FDMA , OFDM-CDMA, and the like. A TDD (Time Division Duplex) scheme in which uplink and downlink transmissions are transmitted using different time periods, or an FDD (Frequency Division Duplex) scheme in which they are transmitted using different frequencies can be used.

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 (CCs). Each element carrier is defined as the bandwidth and center frequency. Carrier aggregation is introduced to support increased throughput, prevent cost increases due to the introduction of wideband radio frequency (RF) devices, and ensure compatibility with existing systems. For example, if five elementary carriers are allocated as the granularity of a carrier unit having a bandwidth of 20 MHz, it can support a bandwidth of up to 100 MHz.

Carrier aggregation can be divided into contiguous carrier aggregation between successive element carriers in the frequency domain and non-contiguous carrier aggregation between discontinuous element carriers. The number of carriers aggregated between the downlink and the uplink may be set differently. The case where the number of downlink element carriers is equal to the number of uplink element carriers is referred to as symmetric aggregation and the case where the number of downlink element carriers is different is referred to as asymmetric aggregation.

The size (i.e. bandwidth) of the element carriers may be different. For example, if five element carriers are used for a 70 MHz band configuration, then 5 MHz element carrier (carrier # 0) + 20 MHz element carrier (carrier # 1) + 20 MHz element carrier (carrier # 2) + 20 MHz element carrier (carrier # 3) + 5 MHz element carrier (carrier # 4).

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

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

Referring to FIG. 2, the common medium access control (MAC) entity 210 manages a physical layer 220 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 220 may operate as a time division duplex (TDD) and / or a frequency division duplex (FDD).

There are several physical control channels used in the physical layer 220. The physical downlink control channel (PDCCH) informs the UE of resource allocation of a paging channel (PCH), a downlink shared channel (DL-SCH), and hybrid automatic repeat request (HARQ) information related to the DL-SCH. The PDCCH may carry an uplink grant informing the UE of the resource allocation of the uplink transmission. A 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. A physical uplink shared channel (PUSCH) carries an uplink shared channel (UL-SCH). A physical random access channel (PRACH) carries a random access preamble.

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

Referring to FIG. 3, the frame consists of 10 subframes. The subframe includes a plurality of OFDM symbols. Each carrier may have its own control channel (eg, PDCCH). The multicarriers may or may not be adjacent to each other. The terminal may support one or more carriers according to its capability.

The component carrier may be divided into a primary component carrier (PCC) and a secondary component carrier (SCC) according to activation. The major carriers are always active carriers, and the subcarrier carriers are carriers that are activated / deactivated according to specific conditions. Activation means that the transmission or reception of traffic data is performed or is in a ready state. Deactivation means that transmission or reception of traffic data is impossible, and measurement or transmission of minimum information is possible. The terminal may use only one major carrier or use one or more sub-carrier with carrier. A terminal may be allocated a primary carrier and / or secondary carrier from a base station.

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

Referring to FIG. 4, the downlink component carriers D1, D2, and D3 are aggregated in the downlink, and the uplink component carriers U1, U2, and U3 are aggregated in the uplink. Where Di is the index of the downlink component carrier and Ui is the index of the uplink component carrier (i = 1, 2, 3). At least one downlink element carrier is a dominant carrier and the remainder is a subordinate element carrier. Similarly, at least one uplink component carrier is a dominant carrier and the remainder is a subindent carrier. For example, D1, U1 are the dominant carriers, and D2, U2, D3, U3 are the subelement carriers.

In the FDD system, the downlink component carrier and the uplink component carrier are configured to be 1: 1. For example, D1 is connected to U1, D2 is U2, and D3 is U1 1: 1. The terminal establishes a connection between the downlink component carriers and the uplink component carriers through system information transmitted by a logical channel BCCH or a terminal-specific RRC message transmitted by a DCCH. Each connection configuration may be set cell specific or UE specific.

4 illustrates only a 1: 1 connection setup between the downlink component carrier and the uplink component carrier, but it is needless to say that a 1: n or n: 1 connection setup can also 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.

The primary serving cell refers to one serving cell that provides security input and NAS mobility information in an RRC connection or re-establishment state. Depending on the capabilities of the terminal, at least one cell may be configured to form a set of serving cells together with a main serving cell, said at least one cell being referred to as a secondary serving cell.

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

The downlink component carrier corresponding to the main serving cell is referred to as a downlink principal carrier (DL PCC), and the uplink component carrier corresponding to the main serving cell is referred to as an uplink principal carrier (UL PCC). In the downlink, the element carrier corresponding to the secondary serving cell is referred to as a downlink sub-element carrier (DL SCC), and in the uplink, an elementary carrier corresponding to the secondary serving cell is referred to as an uplink sub-element carrier (UL SCC) do. Only one DL serving carrier may correspond to one serving cell, and DL CC and UL CC may correspond to each other.

Therefore, the communication between the terminal and the base station through the DL CC or the UL CC in the carrier system is a concept equivalent to the communication between the terminal and the base station through the serving cell. For example, in a method of performing random access, transmitting a preamble by using a UL CC may be considered to be equivalent to transmitting a preamble using a main serving cell or a secondary serving cell. In addition, the UE receiving the downlink information by using the DL CC, can be seen as a concept equivalent to receiving the downlink information by using the primary serving cell or secondary serving cell.

On the other hand, the main serving cell and the secondary serving cell has the following characteristics.

First, the primary serving cell is used for transmission of the PUCCH. On the other hand, the secondary serving cell can not transmit the PUCCH but may transmit some of the information in the PUCCH through the PUSCH.

Second, the main serving cell is always activated, while the secondary serving cell is a carrier that is activated / deactivated according to a specific condition. The specific condition may be when the activation / deactivation MAC CE message of the eNB is received or the deactivation timer in the UE expires.

Third, when the primary serving cell experiences RLF, RRC reconnection is triggered, but when the secondary serving cell experiences RLF, RRC reconnection is not triggered. Radio link failure occurs when downlink performance is maintained below a threshold for more than a certain time, or when the RACH has failed a number of times above the threshold.

Fourth, the main serving cell may be changed by a security key change or a handover procedure accompanied by the RACH procedure. However, in the case of a content resolution message, only a downlink control channel indicating a CR (hereinafter referred to as a 'PDCCH') should be transmitted through the primary serving cell, and the CR information may be transmitted through the primary serving cell or the secondary serving cell. Can be sent through.

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

Sixth, the main serving cell always consists of DL PCC and UL PCC in pairs.

Seventh, a different CC may be set as a primary serving cell for each terminal.

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

Ninth, the main serving cell transmits PDCCH (e.g., downlink allocation information) assigned to a UE-specific search space set for transmitting control information for a specific UE in a region for transmitting control information Or PDCCH (e.g., system information (e.g., uplink information) allocated to a common search space set for transmitting control information to all terminals in the cell or to a plurality of terminals conforming to a specific condition, SI), a random access response (RAR), and transmit power control (TPC). On the other hand, only the UE-specific search space can be set as the serving cell. That is, since the UE can not confirm the common search space through the secondary serving cell, it can not receive the control information transmitted only through the common search space and the data information indicated by the control information.

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

In a multi-carrier system, one terminal communicates with a base station through a plurality of component carriers or a plurality of serving cells. If the signals of the plurality of serving cells configured in the terminal all have the same time delay, the terminal may acquire uplink synchronization for all the serving cells with only the same timing alignment. Hereinafter, a set of serving cells having the same time alignment value is defined as a timing alignment group (TAG). Serving cells belonging to the time alignment group need the same amount of uplink time adjustment. A time alignment group including the main serving cell is called pTAG, and a time alignment group not including the main serving cell (ie, including only the secondary serving cell) is called sTAG. In order for the secondary serving cell to belong to the time alignment group, an uplink component carrier should be configured in the secondary serving cell.

5 is a flowchart illustrating a method of performing uplink synchronization according to an embodiment of the present invention.

Referring to FIG. 5, the terminal performs an RRC connection establishment procedure with the base station (S500). The RRC connection setup procedure includes a terminal transmitting an RRC connection request message to a base station, a base station transmitting an RRC connection setup message to a terminal, and a terminal transmitting an RRC connection setup complete message to a base station. The purpose of the RRC connection establishment procedure is to establish an RRC connection. The RRC connection setup includes setup of a signaling radio bearer (SRB) 1.

The base station performs a secondary serving cell configuration procedure for additionally configuring at least one secondary serving cell to the terminal (S505). The secondary serving cell configuration procedure may be performed through an RRC connection reconfiguration procedure. The RRC connection reconfiguration procedure includes a base station transmitting an RRC connection reconfiguration message to a terminal, and a terminal transmitting an RRC connection reconfiguration complete message to a base station. The RRC connection reconfiguration message may include a secondary serving cell configuration information field including information on the configuration of the secondary serving cell added to the terminal. The RRC connection reconfiguration message and the RRC connection reconfiguration complete message are both transmitted and received on the primary serving cell. The secondary serving cell configuration procedure may be performed when the base station receives a request for more radio resources from the terminal or the network, or when the base station itself determines that more radio resources are needed.

At least one secondary serving cell additionally configured in the terminal may be classified into the same time alignment group as the main serving cell or may be classified into an independent time alignment group. In the case of being classified as an independent time alignment group, the base station does not have clear information about which time alignment group including at least one secondary serving cell configured in the terminal belongs to the pTAG.

The base station transmits to the base station a MAC message including an activation indicator for activating some or all of the secondary serving cells configured in the terminal and time alignment group configuration information (S510). The MAC message may be called a MAC protocol data unit (PDU). The MAC message includes at least one MAC control element (CE), and the MAC control element includes an activation indicator and time alignment group configuration information. As the base station activates some or all of the secondary serving cells, the base station may allocate resources for secondary serving cells configured in the terminal.

The MAC message may or may not include time alignment group configuration information. As an example, if there is a secondary serving cell that may have a time alignment value different from that of the pTAG, the base station may configure an sTAG composed of only the secondary serving cell. In this case, the MAC message may include time alignment group configuration information regarding the pTAG and sTAG. As another example, when a secondary serving cell having a different time alignment value occurs among secondary serving cells belonging to one of pTAG or sTAG, the base station configures a new sTAG having a different time alignment value or time of the secondary serving cell. It can be included in pTAG or sTAG having the same time alignment value as the alignment value. In this case, the MAC message may include time alignment group configuration information including the information on the new sTAG or reconstructed TAG configuration information.

The terminal configures a timing reference serving cell in each time alignment group (S515). The information on the timing reference serving cell may or may not be included in the time alignment group configuration information. The timing reference serving cell may be a component carrier unit rather than a serving cell unit. In this case, the downlink timing reference serving cell may be referred to as a downlink timing reference component carrier. In addition, the timing reference component carrier may be designated by being divided into a downlink component carrier or an uplink component carrier. Accordingly, the terminal may apply the time alignment value provided from the base station to each time alignment group. The timing reference serving cell may be used as the representative serving cell for performing the random access procedure in step S520.

As an example, if information on a timing reference serving cell is not included in the time alignment group configuration information, the representative serving cell indicates a random access procedure for the base station to obtain an initial uplink time alignment value for the corresponding sTAG. It can also be defined as a cell. As another example, if the time alignment timer in any sTAG expires and the time alignment value becomes invalid, the representative serving cell setting may be released.

The timing reference serving cell may have the following characteristics. i) There is one timing reference serving cell for each time alignment group. ii) The timing reference serving cell in pTAG is the primary serving cell. iii) The timing reference serving cell in the sTAG may be configured only with secondary serving cells or primary serving cells in the corresponding sTAG. iv) In the case of sTAG, the timing reference serving cell may be changed.

The UE may perform a random access procedure for obtaining a time alignment value (S520). Through the random access procedure, the UE may obtain a valid time alignment value based on a timing reference serving cell in each time alignment group. The random access procedure for securing the time alignment value of the newly configured sTAG is initiated by the command of the base station. Therefore, in this case, the terminal should receive a random access start indicator indicating the start of the random access procedure for a particular serving cell from the base station. Herein, the specific serving cell may be a representative serving cell in the newly configured sTAG. In the random access procedure, the random access procedure may be non-contention based or contention based. The non-contention based random access procedure may be initiated by an order for performing a random access procedure by the base station. The contention-based random access procedure may be initiated by the terminal transmitting a randomly selected random access preamble to the base station.

Although the base station recognizes that there may be a secondary serving cell having a time alignment value different from that of the pTAG, there may be a case in which sTAG the secondary serving cell belongs to. In this case, when the base station simultaneously transmits the time alignment group configuration information including the new sTAG information consisting of the secondary serving cell and the activation indicator for the secondary serving cell to the terminal, the terminal randomizes the secondary serving cell in the new sTAG from the base station. The access initiation indicator can be quickly received, and the uplink synchronization can be quickly secured in the sTAG to which the secondary serving cell belongs.

6 shows a structure of a MAC message according to an embodiment of the present invention.

Referring to FIG. 6, the MAC message 600 includes a MAC header 610, at least one MAC control element 620, 625, and at least one MAC Service Data Unit (SDU). ) 630-1,..., 630-m and padding 640.

The MAC header 610 includes at least one subheader 610-1, 610-2,..., 610-k, each subheader 610-1, 610-2 ... .610-k correspond to one MAC SDU or one MAC control element 620,..., 625 or padding 640. The order of the subheaders 610-1, 610-2,..., 610-k is the corresponding MAC SDU, MAC control element 620, ..., 625 or padding 640 in the MAC message 600. Are arranged in the same order.

Each subheader 610-1, 610-2, ..., 610-k contains four fields: R, R, E, LCID, or 6 R, R, E, LCID, F, L Field may be included. Subheaders containing four fields are subheaders corresponding to MAC control elements 620, ..., 625 or padding 640, and subheaders containing six fields are subheaders corresponding to MAC SDUs. .

The Logical Channel ID (LCID) field is an identification field that identifies a logical channel corresponding to a MAC SDU, or identifies a MAC control element (620, ..., 625) or a type of padding. When the subheaders 610-1, 610-2,..., 610-k have an octet structure, the LCID field may be 5 bits.

For example, the LCID field may be a MAC control element (hereinafter referred to as activation and TAG configuration) for the MAC control elements 620, ..., 625 to indicate activation / deactivation of the serving cell and time alignment group configuration as shown in Table 1. MAC control element (Activation & TAG MAC CE) can be identified.

LCID Index LCID value 00000 CCCH 00001-01010 Logical channel identifier 01011-11010 Reserved 11011 Enable / Disable and TAG Configuration 11100 UE contention resolution identifier 11101 Time Forward Command (TAC) 11110 DRX command 11111 padding

Referring to Table 1, if the value of the LCID field is 11011, the corresponding MAC control element is a MAC control element for activation and TAG configuration. That is, one subheader, that is, one LCID field, may indicate that the configured MAC control element includes both an activation / deactivation indicator and a TAG configuration.

Alternatively, the LCID field may identify whether the MAC control elements 620, ..., 625 are MAC control elements related to the time alignment group configuration or MAC control elements related to activation / deactivation of the serving cell as shown in Table 2. have.

LCID Index LCID value 00000 CCCH 00001-01010 Logical channel identifier 01011-11001 Reserved 11010 TAG configuration 11011 Activation / deactivation 11100 UE contention resolution identifier 11101 Time Forward Command (TAC) 11110 DRX command 11111 padding

Referring to Table 2, if the value of the LCID field is 11010, the corresponding MAC control element is a MAC control element for activation / deactivation. And if the value of the LCID field is 11011, the corresponding MAC control element is a MAC control element for the TAG configuration.

MAC control elements 620, ..., 625 are control messages generated by the MAC layer. Padding 640 is a predetermined number of bits added to make the size of the MAC message constant. The MAC control elements 620,... 625, MAC SDUs 630-1,..., 630-m, and padding 640 together are also referred to as MAC payloads. Examples of MAC control elements related to activation and TAG configuration are described below.

7 is a block diagram showing the structure of a MAC control element according to an embodiment of the present invention. This represents the MAC control element for activation / deactivation and TAG configuration.

Referring to FIG. 7, the subheader 700 of Embodiment 1 includes two R fields 705, an E field 710, and an LCID field 715. The LCID field 715 corresponds to the MAC control element for activation and TAG configuration if its value is 11011 as shown in Table 1, for example.

The subheader 750 of the second embodiment includes two R fields 755, an E field 760, an LCID field 765, an F field 770, and an L field 775. The LCID field 715 corresponds to the MAC control element for activation and TAG configuration if its value is 11011 as shown in Table 1, for example. When configuring a MAC control element related to activation and TAG configuration in this way, the LCID fields 715 and 765 of the subheaders 700 and 750 may be set to new LCID values.

8 is a block diagram illustrating a structure of a MAC control element according to another example of the present invention. This is the structure of the MAC control element regarding the TAG configuration.

Referring to FIG. 8, the subheader 800 of Embodiment 1 includes two R fields 805, an E field 810, and an LCID field 815. The LCID field 815 corresponds to the MAC control element related to the TAG configuration when the value is 11011, for example, as shown in Table 2.

The subheader 850 of the second embodiment includes two R fields 855, an E field 860, an LCID field 865, an F field 870, and an L field 875. The LCID field 815 corresponds to the MAC control element related to the TAG configuration when the value is 11011, for example, as shown in Table 2.

9 is a block diagram showing the structure of a MAC control element according to another example of the present invention. This is the structure of the MAC control element regarding activation / deactivation.

Referring to FIG. 9, the subheader 900 of Embodiment 1 includes two R fields 905, an E field 910, and an LCID field 915. The LCID field 915 corresponds to a MAC control element for activation / deactivation when the value is 11010, for example, as shown in Table 2.

The subheader 950 of the second embodiment includes two R fields 955, an E field 960, an LCID field 965, an F field 970, and an L field 975. The LCID field 915 corresponds to a MAC control element for activation / deactivation when the value is 11010, for example, as shown in Table 2.

10 shows a structure of a MAC message according to another example of the present invention.

Referring to FIG. 10, the MAC message 1000 includes a MAC header 1010, a first MAC control element MAC CE1 and 1015, a second MAC control element MAC CE2 and 1020, and a padding 1025.

Meanwhile, the MAC header 1010 includes a plurality of subheaders again, and includes a first subheader 1011, a second subheader 1012, and a third subheader 1013. It is merely exemplary that the number of subheaders included in the MAC header 1010 is only three, and may be less than three or more in actual implementation of the present embodiment. The first subheader 1011 includes an R field, an E field, and an LCID field, and the LCID field corresponds to the first MAC control element 1015 which is a MAC control element for activation / deactivation as shown in Table 2. That is, the value of the LCID field in the first subheader 1011 is 11011. Meanwhile, the second subheader 1012 includes an R field, an E field, an F field, an L field, and an LCID field, and the LCID field includes a second MAC control element that is a MAC control element related to the TAG configuration as shown in Table 2. 1020). At this time, the value of the LCID field in the second subheader 1012 is 11010.

The first subheader 1011 and the second subheader 1012 are configured continuously or discontinuously in the structure of the MAC header. In this way, the base station may separate the MAC control element for activation / deactivation and the MAC control element for TAG configuration in one MAC message, and configure the MAC message to be indicated by different LCID fields.

11 shows a structure of a MAC message according to another example of the present invention.

Referring to FIG. 11, the MAC message 1100 includes a MAC header 1110, MAC control elements MAC CE1 and 1115 and padding 1120. Meanwhile, the MAC header 1110 again includes a plurality of subheaders, which are a first subheader 1111 and a second subheader 1112. The number of subheaders included in the MAC header 1110 is set to only two examples, and the present invention may be less than two or more than two in actual implementation. The first subheader 1111 includes an R field, an E field, an F field, an L field, and an LCID field, and the LCID field includes a first MAC control element which is a MAC control element related to activation and TAG configuration as shown in Table 1. 1115). That is, the value of the LCID field in the first subheader 1111 is 11011.

In the E field, the UE determines whether the value of the LCID field according to Table 2 is 11011 so that the MAC control element is related to the activation and the TAG configuration, or the value of the LCID field is 11010 so that the MAC control element is related to the activation and the TAG configuration. Used. This is because the L field is a field that can be added to the subheader for a MAC control element that can have a variable length. Therefore, when the E field is '1', the next 8 bits include an F field of 1 bit and an L field of 7 bits in the corresponding subheader.

The L field is a field indicating the length of a MAC control element or MAC SDU, which may have a variable length. The unit representing the length of the MAC control element or MAC SDU is 1 byte. Therefore, when the L field is 0000010, the length of the MAC control element, which may have a variable length, is 2 bytes (16 bits). If the F field contains less information than the maximum displayable length of the L field of 128 bytes, the F field is set to '0'. Otherwise, it is set to '1'.

Thus, the MAC subheader including the L field corresponds to the MAC control element for activation and TAG configuration. In addition, when the MAC control element includes only the TAG configuration information, the case where the TAG configuration information includes 16 bits or more information is also used. Accordingly, the UE can know whether the L field exists through the E field and can know the total length of the corresponding MAC control element through the information of the L field.

12 illustrates a structure of a MAC control element related to activation and TAG configuration according to an embodiment of the present invention.

Referring to FIG. 12, the MAC control elements for activation and TAG configuration include octet 1 (OCT 1), ..., octet K + 1 (OCT K + 1). One octet is 8 bits and contains information on activation and TAG configuration. Octet 1 is assigned to an activation indicator. The position of each bit of the activation indicator is mapped to a serving cell index (ServCell-index) or a secondary serving cell index (SCell-index). A value of 0 indicates that the serving cell mapped to the bit is deactivated, and a value of 1 indicates that the serving cell mapped to the bit is activated. The least significant bit means index 0 and the most significant bit means index 7. On the other hand, the least significant bit is composed of reserved bits. This is because the main serving cell is always activated, so it is meaningless to indicate activation / deactivation by the activation indicator.

Octet 2 through octet K + 1 contain TAG configuration information. When the TAG set in the terminal is TAG '0' TAG '1', ..., TAG 'N', the indicator indicating the serving cell included in each TAG is composed of 8 bits.

First, TAG '0' is a pTAG, and configuration information of TAG '0' is assigned to only one octet (octet 2). The location of each bit is mapped to a serving cell index (ServCell-index) or a secondary serving cell index (SCell-index). The least significant bit means index 0 and the most significant bit means index 7. On the other hand, the least significant bit is composed of reserved bits. The timing reference serving cell of TAG '0' is the main serving cell. Therefore, even if the main serving cell is not represented in the configuration information bit string of TAG '0', it can be considered that it is implicitly included in TAG '0. Similarly, even if the main serving cell is not represented in the configuration information bit string of the TAG 'N', it may be considered that it is not implicitly included in the TAG 'N'. In addition, there is no timing reference field indicating a timing reference serving cell for TAG '0'. Therefore, 8 bits are always allocated to the configuration information of TAG '0'.

Next, TAG '1' through TAG 'N' are sTAGs, and configuration information of TAG '1' through TAG 'N' is allocated to two octets. For example, configuration information of TAG '1' is allocated to octets 3 and 4, and configuration information of TAG 'N' is allocated to octets K and octet K + 1.

The configuration information of the TAG '1' includes a 7-bit serving cell indicating field indicating a serving cell included in the TAG '1', a 1-bit reserved bit, and a timing reference serving cell of the TAG '1'. A 3-bit timing reference field and 5-bit reserved field. That is, a total of 16 bits are allocated to the configuration information of one sTAG. Similarly, the configuration information of the TAG 'N' includes a 7-bit serving cell indication field indicating a serving cell included in the TAG 'N', 1 bit of reserved bits, and 3 bits indicating a timing reference serving cell of the TAG 'N'. A timing reference field, and a 5-bit reserved field.

Since the timing reference field is 3 bits, 2 ³ = 8 serving cells can be indicated. That is, the timing reference field may indicate an index of a serving cell designated as a timing reference serving cell among up to eight serving cells. Although the timing reference field has been exemplified by three bits, of course, various numbers of bits may be used in the construction of the timing reference field.

13 shows a structure of a MAC control element related to TAG configuration according to an embodiment of the present invention.

Referring to FIG. 13, the MAC control element related to the TAG configuration includes octet 1 (OCT 1),..., Octet K + 1 (OCT K + 1). One octet is 8 bits and contains information on the TAG configuration.

First, TAG '0' is a pTAG, and configuration information of TAG '0' is assigned to only one octet (octet 1). The location of each bit is mapped to a serving cell index (ServCell-index) or a secondary serving cell index (SCell-index). The least significant bit means index 0 and the most significant bit means index 7. Meanwhile, the most significant bit is composed of reserved bits. The timing reference serving cell of TAG '0' is the main serving cell. Therefore, even if the main serving cell is not represented in the configuration information bit string of TAG '0', it can be considered that it is implicitly included in TAG '0. Similarly, even if the main serving cell is not represented in the configuration information bit string of the TAG 'N', it may be considered that it is not implicitly included in the TAG 'N'.

Next, TAG '1' through TAG 'N' are sTAGs, and configuration information of TAG '1' through TAG 'N' is allocated to two octets. For example, configuration information of TAG '1' is allocated to octets 2 and 3, and configuration information of TAG 'N' is allocated to octets K and octet K + 1.

The configuration information of TAG '1' includes an 8-bit serving cell indication field (OCT 2) indicating a serving cell included in TAG '1' and an 8-bit timing reference field indicating a timing reference serving cell of TAG '1'. (OCT 3). That is, a total of 16 bits are allocated to the configuration information of one sTAG. Similarly, the configuration information of TAG 'N' includes an 8-bit serving cell indication field (OCT K) indicating a serving cell included in TAG 'N' and an 8-bit timing indicating a timing reference serving cell of TAG 'N'. Contains a reference field (OCT K + 1).

Here, the timing reference field is in a bitmap format, and each bit is mapped to one unique serving cell. Accordingly, if a bit of an arbitrary position is 1, it indicates that the serving cell to which the bit is mapped is a timing reference serving cell. If a bit of an arbitrary position is 0, it indicates that the serving cell to which the bit is mapped is not a timing reference serving cell. do. This is the same form as the serving cell indication field. The timing reference field should indicate only one of the serving cells included in the corresponding TAG. That is, only one bit of 8 bits is set to 1, and all other bits are set to 0.

The base station should inform the terminal of the information on the serving cell as a reference for the terminal to measure the pathloss (pathloss). The serving cell as a reference for measuring path loss is called a path loss reference serving cell. The path reduction reference serving cell may be set in units of each serving cell or in units of time alignment groups. The path attenuation reference serving cell may be fixedly configured as a downlink component carrier connected to an uplink center frequency in a system information block 2 (SIB2) related to the path attenuation reference serving cell. The downlink component carrier is referred to hereinafter as a 'SIB2 linked downlink component carrier'.

As an example, the information on the path loss reference serving cell may be included in an RRC message and transmitted from the base station to the terminal. At this time, the range of the serving cell that can be indicated by the RRC message may be limited to the primary serving cell or the SIB2 connection downlink component carrier for the serving cells in the pTAG. In addition, the serving cells in the sTAG may be fixed to the SIB2 connection downlink component carrier or limited to secondary serving cells in the corresponding sTAG.

As another example, the information about the path loss reference serving cell may be transmitted from the base station to the terminal as a MAC message. For example, the path loss reference serving cell may be defined in the same manner as the timing reference serving cell in the MAC message. In this case, the MAC control element related to the TAG configuration includes only a timing reference field. The serving cell indicated by the timing reference field is a timing reference serving cell and a path loss reference serving cell. Alternatively, the path loss reference serving cell may be defined separately from the timing reference serving cell in the MAC message. This is because the criteria for determining the path attenuation reference and the timing reference can be set differently from each other. The MAC control element related to the TAG configuration includes a timing reference field and a path loss reference field. This is explained in more detail in FIG. 14.

14 shows a structure of a MAC control element related to TAG configuration according to another embodiment of the present invention.

Referring to FIG. 14, the MAC control element related to the TAG configuration includes octet 1 (OCT 1),..., Octet K + 1 (OCT K + 1). One octet is 8 bits and contains information on the TAG configuration.

First, TAG '0' is a pTAG, and configuration information of TAG '0' is assigned to only one octet (octet 1). The location of each bit is mapped to a serving cell index (ServCell-index) or a secondary serving cell index (SCell-index). The least significant bit means index 0 and the most significant bit means index 7. Meanwhile, the most significant bit is composed of reserved bits. The timing reference serving cell of TAG '0' is the main serving cell. Therefore, even if the main serving cell is not represented in the configuration information bit string of TAG '0', it can be considered that it is implicitly included in TAG '0. Similarly, even if the main serving cell is not represented in the configuration information bit string of the TAG 'N', it may be considered that it is not implicitly included in the TAG 'N'.

Next, TAG '1' through TAG 'N' are sTAGs, and configuration information of TAG '1' through TAG 'N' is allocated to two octets. For example, configuration information of TAG '1' is allocated to octets 2 and 3, and configuration information of TAG 'N' is allocated to octets K and octet K + 1.

The configuration information of the TAG '1' includes an 8-bit serving cell indication field (OCT 2) indicating a serving cell included in the TAG '1' and a 3-bit timing reference field indicating a timing reference serving cell of the TAG '1'. And a 3-bit path loss reference field (OCT 3) indicating a path loss reference serving cell of TAG '1'. The remaining bits are set to the R field. That is, a total of 16 bits are allocated to the configuration information of one sTAG. Similarly, the configuration information of TAG 'N' includes an 8-bit serving cell indication field (OCT K) indicating a serving cell included in TAG 'N' and a 3-bit timing indicating a timing reference serving cell of TAG 'N'. A reference field and a 3-bit path loss reference field (OCT K + 1) indicating a path loss reference serving cell of TAG 'N'.

Since the timing reference field is 3 bits, 2 ³ = 8 serving cells can be indicated. That is, the timing reference field may indicate an index of a serving cell designated as a timing reference serving cell among up to eight serving cells. In addition, since the path loss reference field is 3 bits, 2 ³ = 8 serving cells can be indicated. That is, the path loss reference field may indicate an index of a serving cell designated as a path loss reference serving cell among up to eight serving cells. Although the timing reference field and the path loss reference field have been given as three bits, of course, various numbers of bits may be used in the configuration of the timing reference field and the path reduction reference field.

15 shows a structure of a MAC control element related to TAG configuration according to another embodiment of the present invention.

Referring to FIG. 15, configuration information of a TAG may include only a serving cell indication field indicating the serving cells included in the TAG. That is, the configuration information of the TAG does not include a timing reference field or a path attenuation reference field unlike the embodiment of FIG. 14. This may be the case when information about a timing reference serving cell or information about a path reduction reference serving cell is transmitted through RRC signaling, or a serving cell in which a base station instructs a random access procedure for the first time after a time alignment group is configured. It may be defined as attenuation reference serving cell.

On the other hand, when the maximum number of time alignment groups configurable to the terminal is limited to two, and two time alignment groups are configured in the actual terminal, the base station controls the MAC including only the configuration information of the pTAG as in the first or second embodiment. The element may be transmitted to the terminal. In other words, configuration information of other TAG except pTAG is not included in the MAC control element. That is, the configuration information of the TAG for one TAG in the MAC control element can be omitted. Therefore, there is an effect that can inform the terminal of the configuration information of the TAG for the two TAG with only one octet (8 bits). In this case, the terminal sets the serving cell not included in the pTAG to sTAG. In the first embodiment, the secondary serving cell 1, the secondary serving cell 2, .... secondary serving cell 7 are sequentially mapped from the least significant bit to the most significant bit. Of course, the order in which each secondary serving cell is mapped to the serving cell indication field is not limited thereto.

In the first embodiment, only the bit mapped to the secondary serving cell 4 is 1 and the remaining bits are all 0. That is, TAG '0' includes the main serving cell and the secondary serving cell 4. If the UE is configured with the main serving cell, secondary serving cell 1, secondary serving cell 2, secondary serving cell 4, since the primary serving cell and secondary serving cell 4 constitutes the TAG '0', it does not belong to the TAG '0' The secondary serving cell 1 and the secondary serving cell 2 are included in TAG'1 'that is the sTAG.

If TAG '0' includes all secondary serving cells configured in the terminal, the terminal may set TAG '1' to an empty sTAG (empty sTAG). An empty sTAG may be constructed in the following situations. i) When all secondary serving cells in sTAG are released, ii) When all uplink component carriers of secondary serving cells in sTAG are released.

Embodiment 2 shows the MAC control element when the position of the case R field is present in the least significant bit, unlike in Embodiment 1.

16 shows a structure of a MAC control element related to TAG configuration according to another embodiment of the present invention.

Referring to FIG. 16, configuration information of a TAG may include only a serving cell indication field indicating the serving cells included in the TAG. That is, the configuration information of the TAG does not include a timing reference field or a path attenuation reference field unlike the embodiment of FIG. 14. This may be the case when information about a timing reference serving cell or information about a path reduction reference serving cell is transmitted through RRC signaling, or a serving cell in which a base station instructs a random access procedure for the first time after a time alignment group is configured. It may be defined as attenuation reference serving cell.

On the other hand, if the maximum number of time alignment groups configurable in the terminal is limited to K, and actually three time alignment groups are configured in the terminal, the base station, as in Embodiment 1 or Embodiment 2, the configuration information of the TAG for the pTAG, 1 The MAC control element including only the configuration information of the TAGs for the sTAGs may be transmitted to the terminal. In other words, configuration information of other sTAG except pTAG and one sTAG is not included in the MAC control element. That is, the configuration information of the TAG for one TAG in the MAC control element can be omitted. Therefore, there is an effect that can inform the terminal of the configuration information of the TAG for the three TAG with only two octets (16 bits). Embodiment 2 shows the MAC control element when the position of the case R field is present in the least significant bit, unlike in Embodiment 1.

The MAC control element including the TAG configuration information of FIGS. 13 to 16 may be equally applied to the structure of the MAC control element related to the activation and TAG configuration including an activation indicator as shown in FIG. 12.

17 is a flowchart illustrating a method of performing uplink synchronization of a terminal according to an embodiment of the present invention.

Referring to FIG. 17, the terminal performs an RRC connection establishment procedure with a base station (S1700). The RRC connection setup procedure includes a terminal transmitting an RRC connection request message to a base station, a base station transmitting an RRC connection setup message to a terminal, and a terminal transmitting an RRC connection setup complete message to a base station. The purpose of the RRC connection establishment procedure is to establish an RRC connection. The RRC connection setup includes the setup of signaling radio bearer1.

The terminal performs a secondary serving cell configuration procedure for additionally configuring at least one secondary serving cell in the terminal (S1705). The secondary serving cell configuration procedure may be performed through an RRC connection reconfiguration procedure. The RRC connection reconfiguration procedure includes a base station transmitting an RRC connection reconfiguration message to a terminal, and a terminal transmitting an RRC connection reconfiguration complete message to a base station. The RRC connection reconfiguration message may include a secondary serving cell configuration information field including information on the configuration of the secondary serving cell added to the terminal.

The terminal receives the MAC message from the base station (S1710). The MAC message may be called a MAC PDU. The MAC message includes at least one MAC control element. The MAC control element includes the structure of any one of FIGS. 12 to 16. The MAC control element may be one MAC control element including activation and TAG configuration, may be a MAC control element regarding activation, or may be a MAC control element regarding TAG configuration. That is, the MAC message may or may not include time alignment group configuration information. As an example, if there is a secondary serving cell that may have a time alignment value different from that of the pTAG, the base station may configure an sTAG composed of only the secondary serving cell. In this case, the MAC message may include time alignment group configuration information regarding the pTAG and sTAG. As another example, when a secondary serving cell having a different time alignment value occurs among secondary serving cells belonging to one of pTAG or sTAG, the base station configures a new sTAG having a different time alignment value or time of the secondary serving cell. It can be included in pTAG or sTAG having the same time alignment value as the alignment value. In this case, the MAC message may include time alignment group configuration information including the information on the new sTAG or reconstructed TAG configuration information.

The UE configures a downlink timing reference serving cell in each time alignment group (S1715). Accordingly, the terminal may apply the time alignment value provided from the base station to each time alignment group. The information on the timing reference serving cell may or may not be included in the time alignment group configuration information. The timing reference serving cell may be a component carrier unit rather than a serving cell unit. In this case, the downlink timing reference serving cell may be referred to as a downlink timing reference component carrier. In addition, the timing reference component carrier may be designated by being divided into a downlink component carrier or an uplink component carrier. Accordingly, the terminal may apply the time alignment value provided from the base station to each time alignment group. The timing reference serving cell may be used as a representative serving cell for performing a random access procedure.

As an example, if information on a timing reference serving cell is not included in the time alignment group configuration information, the representative serving cell indicates a random access procedure for the base station to obtain an initial uplink time alignment value for the corresponding sTAG. It can also be defined as a cell. As another example, if the time alignment timer in any sTAG expires and the time alignment value becomes invalid, the representative serving cell setting may be released.

The timing reference serving cell may have the following characteristics. i) There is one timing reference serving cell for each time alignment group. ii) The timing reference serving cell in pTAG is the primary serving cell. iii) The timing reference serving cell in the sTAG may be configured only with secondary serving cells or primary serving cells in the corresponding sTAG. iv) In the case of sTAG, the timing reference serving cell may be changed.

18 is a flowchart illustrating a method of performing uplink synchronization by a base station according to an embodiment of the present invention.

Referring to FIG. 18, the base station performs an RRC connection establishment procedure with a terminal (S1800). The RRC connection setup procedure includes a terminal transmitting an RRC connection request message to a base station, a base station transmitting an RRC connection setup message to a terminal, and a terminal transmitting an RRC connection setup complete message to a base station. The purpose of the RRC connection establishment procedure is to establish an RRC connection. The RRC connection setup includes the setup of signaling radio bearer1.

The base station performs a secondary serving cell configuration procedure for additionally configuring at least one secondary serving cell in the terminal (S1805). The secondary serving cell configuration procedure may be performed through an RRC connection reconfiguration procedure. The RRC connection reconfiguration procedure includes a base station transmitting an RRC connection reconfiguration message to a terminal, and a terminal transmitting an RRC connection reconfiguration complete message to a base station. The RRC connection reconfiguration message may include a secondary serving cell configuration information field including the content of the secondary serving cell added to the terminal.

The base station transmits a MAC message including an activation indicator for activating some or all of the secondary serving cells configured in the terminal and time alignment group (TAG) configuration information to the terminal (S1810). The MAC message may be called a MAC PDU. The MAC message includes at least one MAC control element, which is a MAC control element for activation and TAG configuration. The MAC control element includes the structure of any one of FIGS. 12 to 16.

If necessary, the base station may inform the terminal of each time alignment value for at least one time alignment group configured in the terminal by performing a random access procedure with the terminal.

The time alignment group configuration information may be transmitted as included in an RRC message as well as a MAC message. Table 3 is an example of an RRC message including secondary serving cell configuration information.

RRCConnectionReconfiguration-v1020-IEs :: = SEQUENCE {
sCellToReleaseList-r10 SCellToReleaseList-r10 OPTIONAL,-Need ON
sCellToAddModList-r10 SCellToAddModList-r10 OPTIONAL,-Need ON
nonCriticalExtension SEQUENCE {} OPTIONAL-Need OP
}

SCellToAddModList-r10 :: = SEQUENCE (SIZE (1..maxSCell-r10)) OF SCellToAddMod-r10

SCellToAddMod-r10 :: = SEQUENCE {
sCellIndex-r10 SCellIndex-r10,
cellIdentification-r10 SEQUENCE {
physCellId-r10 PhysCellId,
dl-CarrierFreq-r10 ARFCN-ValueEUTRA
} OPTIONAL, - Cond SCellAdd
radioResourceConfigCommonSCell-r10 RadioResourceConfigCommonSCell-r10 OPTIONAL, - Cond SCellAdd
radioResourceConfigDedicatedSCell-r10 RadioResourceConfigDedicatedSCell-r10 OPTIONAL, - Cond SCellAdd2
...
}

Referring to Table 3, the sCellToReleaseList-r10 field includes list information of secondary serving cells to be deconfigured, and the sCellToAddModList-r10 field includes list information of secondary serving cells to be further configured or secondary serving cells to be changed. do.

The sCellToAddModList-r10 field is composed of a set of at least one SCellToAddMod-r10 field, and a maximum value that can be included is defined by a maxSCell-r10 field. The SCellToAddMod-r10 field is a radioResourceConfigCommonSCell-r10 field which is common configuration information for all secondary serving cells to be additionally configured or changed in configuration, a radioResourceConfigDedicatedSCell-r10 field which is dedicated information for a secondary serving cell, and a sub-component configured in the terminal. SCellIndex-r10 field including UE-specific index information for a serving cell, and cellIdentification-r10 field including information used for identification by the LTE system for the secondary serving cell.

The cellIdentification-r10 field includes a dl-CarrierFreq-r10 field including information on physical frequency resources and a physCellId-r10 field including logical cell index information.

In addition, in the syntax commented (-) in Table 2, the meaning of the SCellAdd syntax means that the field is always present when the secondary serving cell is added, and if not, the field does not exist. In addition, the meaning of the SCellAdd2 syntax is a field that always exists when a secondary serving cell is added. If not, it may be optionally present if necessary. The phrase 'Need ON' indicates that the terminal does not perform any operation when a corresponding field does not exist with respect to an optional field. In the case of a 'Need OP' syntax, if a corresponding field does not exist with respect to an optional field, the terminal operates according to the detailed content indicated in the description of the corresponding field. If the above content does not exist, the terminal does not perform any operation. The ‘Cond’ statement stands for Conditional. For example, Cond SCellAdd means 'newly added secondary serving cell'.

Here, the configuration information (RadioResourceConfigDedicatedSCell-r10) field dedicated to the secondary serving cell includes a time alignment group index field which is time alignment group configuration information as shown in Table 4.

RadioResourceConfigDedicatedSCell-r10 :: = SEQUENCE {
...
TAG_index TAG_index OPTIONAL,-Need OP,
...
}

Referring to Table 4, TAG_index is an index field of a time alignment group.

Table 5 shows another example of an RRC message including time alignment group configuration information.

MAC-MainConfig :: = SEQUENCE {
...
tagToAddModList-r11 :: = SEQUENCE (SIZE (1..maxTAG-r11)) OF TAG-Config OPTIONAL,-Need ON,
tagToReleaseList-r11 TagToReleaseList-r11 OPTIONAL,-Need ON
TAG-Config :: = SEQUENCE {
tag_index TAG_Index,
ServCells BIT STRING (8),
timeAlignmentTimerDedicated TimeAlignmentTimer
}
TagToReleaseList-r11 :: = SEQUENCE (SIZE (1..maxTAG-r11)) OF TAG_Index
...
}

Referring to Table 5, MAC-MainConfig is included in the RadioResourceConfigDedicated field transmitted to the terminal through an RRC reconfiguration message and transmitted. In addition, the tagToAddModList field includes list information about a newly added or changed TAG, and the tagToReleaseModList field includes list information about a TAG to be released. The pTAG may not be included in the release list information. In addition, the time alignment group index field indicates an index of the corresponding time alignment group. For example, when the value of the time alignment group index field is 0, it means pTAG. Otherwise, it means sTAG. The ServCells field contains list information about the serving cells included in the corresponding TAG. The bit string representing the list information of the ServCells field applies the same rule as that of the serving cells included in one TAG shown in FIGS. 15 to 16.

If the maximum number of time alignment groups configurable in the terminal is limited to two and two time alignment groups are configured in the actual terminal, an RRC message including only configuration information of the pTAG may be transmitted to the terminal. In other words, configuration information of other TAG except pTAG is not included in the RRC message. Alternatively, an RRC message including only configuration information of the sTAG may be transmitted to the terminal. In other words, the configuration information of the pTAG is not included in the RRC message. That is, the configuration information of the TAG for one TAG in the RRC message may be omitted. In this case, the terminal sets the serving cell not included in the pTAG to sTAG.

On the other hand, if the maximum number of time alignment groups configurable in the terminal is limited to K, and in fact, three time alignment groups are configured in the terminal, the base station only configures the configuration information of the TAG for the pTAG and the configuration information of the TAG for one sTAG. The RRC message may be transmitted to the terminal. In other words, configuration information of other sTAG except pTAG and one sTAG is not included in the RRC message. Alternatively, the base station may transmit an RRC message including only configuration information of the TAG for the sTAG to the terminal. In other words, the configuration information of the pTAG except for the sTAG is not included in the RRC message. That is, the configuration information of the TAG for one TAG in the RRC message may be omitted. Therefore, there is an effect that can inform the terminal of the configuration information of the TAG for the three TAGs only with information on the two TAGs. In addition, maxTAG-r11 may have a value of 'maximum configurable TAG number -1'.

The process of transmitting the RRC message including the time alignment group configuration information is illustrated in FIG. 19A.

Referring to FIG. 19A, the terminal and the base station perform an RRC connection setup procedure (S1900). In the RRC connection establishment procedure, the terminal transmits an RRC connection establishment request message to the base station, the base station transmits an RRC connection setup to the terminal, and the terminal transmits an RRC connection establishment complete message to the base station. It includes a step. The RRC connection setup procedure includes the setup of SRB1.

The base station configures a time alignment group (S1905). The time alignment group may include a main serving cell, may include at least one secondary serving cell, and may include a primary serving cell and at least one secondary serving cell. As an example, the base station may configure a time alignment group specific to the terminal. Since the serving cell configuration information is configured individually and independently for each terminal, the time alignment group may also be configured individually and independently for each terminal. For example, the time alignment groups for the first terminal are TAG1_UE1 and TAG2_UE1, and the time alignment groups for the second terminal are TAG1_UE2 and TAG2_UE2. TAG1_UE1 = {first serving cell}, TAG2_UE1 = {second serving cell} when the first and second serving cells are configured in the first terminal, whereas TAG1_UE2 = when the first to fourth serving cells are configured in the second terminal. {First serving cell, second serving cell}, TAG2_UE2 = {third serving cell, fourth serving cell}.

As another example, the base station may configure a time alignment group specific to the cell. Since the network configuration information is determined irrespective of the terminal, the time alignment group may be configured cell-centric regardless of the terminal. For example, assume that a first serving cell of a specific frequency band is always served by a frequency selective repeater or a remote radio head, and a second serving cell is served by a base station. In this case, the first serving cell and the second serving cell are classified into different time alignment groups for all terminals in the service area of the base station.

The base station performs an RRC connection reconfiguration procedure for reconfiguring the secondary serving cell (S1910). The RRC connection reconfiguration procedure is performed by the base station transmitting an RRC connection reconfiguration message to the terminal and the terminal transmitting an RRC connection reconfiguration complete message to the base station. At this time, the time alignment group configuration information is included in the RRC connection reconfiguration message.

The terminal receiving the time alignment group configuration information may configure a time alignment group as follows. First, the primary serving cell is always included in the pTAG. Secondary serving cells for which the time alignment group index field is not defined are components in pTAG. On the other hand, secondary serving cells in which the time alignment group index field is defined are included in the sTAG indicated by the corresponding time alignment group index.

19B is a block diagram illustrating a terminal and a base station performing a random access procedure according to an embodiment of the present invention.

Referring to FIG. 19B, the terminal 1900 includes a terminal receiver 1905, a terminal processor 1910, and a terminal transmitter 1915. The terminal processor 1910 includes an RRC message processor 1911 and a MAC message processor 1912.

The terminal receiver 1905 receives RRC connection configuration related information, secondary serving cell configuration related information, and a MAC message from the base station 1950. The RRC connection setup related information includes an RRC connection setup message. The secondary serving cell configuration related information includes an RRC connection reconfiguration message.

The RRC message processor 1911 analyzes the RRC connection setup message and the RRC connection reconfiguration message and performs RRC related procedures. For example, the secondary serving cell to be added to the terminal 1900 may be configured. In addition, based on the activation indicator of the MAC message analyzed by the MAC message processing unit 1912, to activate or deactivate the state of the secondary serving cell configured in the terminal 1900.

The MAC message processing unit 1912 analyzes the MAC message received by the terminal receiving unit 1905 and activates some or all of the secondary serving cells configured in the terminal 1900 and time alignment group (TAG) configuration information. Acquire it. The MAC message may be called a MAC PDU and may be any one of the structures of FIGS. 6 to 11. The MAC message includes at least one MAC control element, which is a MAC control element for activation and TAG configuration. The MAC control element includes the structure of any one of FIGS. 12 to 16.

The terminal transmitter 1915 transmits the RRC connection setup related information including the RRC connection request message, the RRC connection setup complete message, and the secondary serving cell configuration related information including the RRC connection reconfiguration complete message to the base station 1950.

The base station 1950 includes a base station transmitter 1955, a base station receiver 1960, and a base station processor 1970. The base station processor 1970 includes a cell component 1971 and a TAG processor 1972.

The base station transmitter 1955 transmits RRC connection configuration related information, secondary serving cell configuration related information, and a MAC message to the terminal 1900.

The base station receiving unit 1965 receives a RRC connection request information, an RRC connection setup related information including an RRC connection setup complete message, and a secondary serving cell configuration related information including an RRC connection reconfiguration complete message from a terminal 1900 to configure a cell. Sent to Department (1971).

The cell constitution unit 1971 determines the secondary serving cell to be initially configured in the terminal 1900 or additionally configured in the terminal 1900 and configures the secondary serving cell for configuring the determined secondary serving cell in the terminal 1900. The information is generated and sent to the base station transmitter 1955.

The TAG processor 1972 determines activation or deactivation of each secondary serving cell configured in the terminal 1900 and determines a time alignment group specifically configured for the terminal 1900. The TAG processing unit 1972 generates a MAC message including an activation indicator indicating activation or deactivation of the determined secondary serving cell and TAG configuration information instructing the terminal 1900 to configure the determined time alignment group. Send to section 1955.

The various illustrative logic blocks, modules, and circuits described in connection with the embodiments disclosed herein may be general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or It may be controlled with other programmable logic devices, discrete gate or transistor logic, discrete hardware components or any combination thereof designed to perform the functions described herein. Control steps of the method or algorithm described in connection with the embodiments disclosed herein may be implemented directly in hardware, in a software module executed by a processor, or in a combination thereof. In one or more illustrative embodiments, the described control functions may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored or transmitted as one or more instructions or code on a computer-readable medium.

Claims (14)

In the method of performing uplink synchronization by the terminal in a multi-component carrier system,
Receiving secondary serving cell configuration information including information used to configure at least one secondary serving cell in a terminal from a base station;
Configuration information regarding a timing alignment group (TAG), which is a set of an activation indicator indicating activation or deactivation of a secondary serving cell configured in the terminal and a secondary serving cell having the same uplink timing alignment value Receiving a medium access control (MAC) message from the base station; And
And setting the state of the secondary serving cell configured in the terminal to be activated or deactivated according to the indication of the activation indicator. The method of claim 1,
The MAC message includes a MAC subheader and a MAC control element (CE),
The MAC control element includes configuration information regarding the activation indicator and the time alignment group,
The MAC subheader may include a logical channel ID (LCID) field indicating that the MAC control element includes configuration information regarding the activation indicator and the time alignment group. How to do it. The method of claim 1,
The configuration information about the time alignment group may be based on a serving cell indication field indicating an index of a secondary serving cell included in the time alignment group and an uplink time in the secondary serving cell included in the time alignment group. And information on a timing reference serving cell to be performed. The method of claim 3, wherein
The configuration information about the time alignment group further includes information about a path loss reference serving cell which is a reference for measuring pathloss in a secondary serving cell included in the time alignment group. How to perform link synchronization. In the method of performing uplink synchronization by a base station in a multi-component carrier system,
Transmitting secondary serving cell configuration information including information used to configure at least one secondary serving cell to the terminal; And
Transmitting an MAC message including an activation indicator indicating activation or deactivation of a secondary serving cell configured in the terminal and configuration information regarding a time alignment group which is a set of secondary serving cells having the same uplink time alignment value to the terminal; Method of performing uplink synchronization, characterized in that it comprises a. The method of claim 5, wherein
The MAC message includes a MAC subheader and a MAC control element.
The MAC control element includes configuration information regarding the activation indicator and the time alignment group,
And the MAC subheader includes a logical channel identification field indicating that the MAC control element includes configuration information regarding the activation indicator and the time alignment group. The method of claim 5, wherein
The configuration information about the time alignment group may be based on a serving cell indication field indicating an index of a secondary serving cell included in the time alignment group and an uplink time in the secondary serving cell included in the time alignment group. And information on a timing reference serving cell to be performed. The method of claim 7, wherein
The configuration information about the time alignment group further includes information about a path loss reference serving cell which is a reference for measuring path loss in a secondary serving cell included in the time alignment group. How to do it. A terminal performing uplink synchronization in a multi-component carrier system,
A terminal receiver for receiving secondary cell configuration information and MAC messages including information used to configure at least one secondary serving cell in the terminal from a base station;
An RRC message processor configured to configure a secondary serving cell in the terminal based on the secondary serving cell configuration information, and to set the state of the secondary serving cell configured in the terminal to be activated or deactivated according to the indication of the activation indicator;
A MAC message processing unit for obtaining configuration information regarding a time alignment group, which is a set of an activation indicator indicating activation or deactivation of a secondary serving cell configured in the terminal and a secondary serving cell having the same uplink time alignment value, from the MAC message; And
And a terminal transmitter for transmitting an RRC connection reconfiguration complete message to the base station in response to the reception of the secondary serving cell configuration information. The method of claim 9,
The MAC message includes a MAC subheader and a MAC control element.
The MAC control element includes configuration information regarding the activation indicator and the time alignment group,
And the MAC subheader includes a logical channel identification field indicating that the MAC control element includes configuration information regarding the activation indicator and the time alignment group. The method of claim 9,
The configuration information about the time alignment group may be based on a serving cell indication field indicating an index of a secondary serving cell included in the time alignment group and an uplink time in the secondary serving cell included in the time alignment group. And information about a timing reference serving cell to be included. The method of claim 11,
And the configuration information about the time alignment group further includes information about a path loss reference serving cell serving as a reference for measuring path loss in a secondary serving cell included in the time alignment group. A base station performing uplink synchronization in a multi-component carrier system,
A cell configuration unit configured to determine at least one secondary serving cell to be configured in the terminal, and to generate secondary serving cell configuration information used to configure the determined secondary serving cell in the terminal;
A TAG processor configured to generate an MAC message including an activation indicator indicating activation or deactivation of a secondary serving cell configured in the terminal and configuration information regarding a time alignment group specifically configured for the terminal; And
And a base station transmitter for transmitting the MAC message to the terminal. The method of claim 13,
The MAC message includes a MAC subheader and a MAC control element.
The MAC control element includes configuration information regarding the activation indicator and the time alignment group,
And the MAC subheader includes a logical channel identification field indicating that the MAC control element includes configuration information regarding the activation indicator and the time alignment group.

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