WO2011083990A2 - Method and device for sending data via cross-carrier scheduling in wireless communication system supporting plurality of component carriers - Google Patents

Abstract

The present invention relates to an operating method for terminals for sending data bursts via cross-carrier scheduling in a system supporting a plurality of component carriers, comprising the steps of: receiving, from a base station, downlink control information (DCI) including a carrier indicator field (CIF), via a downlink control channel (PDCCH) in a control region within a subframe; identifying a downlink component carrier indicated by the carrier indicator field, and then determining the uplink component carrier in which a linkage has been set with the downlink component carrier so identified; and sending an uplink data burst to the base station via the uplink component carrier so determined.

Description

Method and apparatus for data transmission through cross-carrier scheduling in a wireless communication system supporting a plurality of component carriers

The present invention relates to wireless communication, and more particularly, to a data transmission method through cross-carrier scheduling and a terminal device using the same in a wireless communication system supporting a plurality of component carriers.

As an example of a mobile communication system to which the present invention can be applied, a 3GPP LTE (3rd Generation Partnership Project Long Term Evolution, hereinafter referred to as 'LTE'), and an LTE-Advanced (hereinafter referred to as 'LTE-A') communication system are outlined. Explain.

One or more cells exist in one base station. The cell is set to one of the bandwidth of 1.25MHz, 2.5MHz, 5MHz, 10MHz, 15MHz, 20MHz, etc. for one carrier to provide a downlink / uplink transmission service to multiple terminals. In this case, different cells may be configured to provide different bandwidths. The base station controls data transmission and reception for a plurality of terminals. The base station transmits downlink scheduling information for downlink data and informs the user equipment of time / frequency domain, encoding, data size, and hybrid automatic repeat and reQuest (HARQ) related information. In addition, the base station transmits uplink scheduling information to the corresponding terminal for uplink (UL) data and informs the user of the time / frequency domain, encoding, data size, and hybrid automatic retransmission request related information. An interface for transmitting user traffic or control traffic may be used between base stations.

Wireless communication technology has been developed up to LTE based on Wideband Code Division Multiple Access (WCDMA), but the needs and expectations of users and operators continue to increase. In addition, as other radio access technologies continue to be developed, new technological evolution is required to be competitive in the future. Reduced cost per bit, increased service availability, the use of flexible frequency bands, simple structure and open interface, and adequate power consumption of the terminal are required.

Recently, 3GPP is working on standardization of subsequent technologies for LTE. In the present specification, the above technique is referred to as 'LTE-A'. One of the major differences between LTE and LTE-A systems is the difference in system bandwidth and the introduction of repeaters.

The LTE-A system aims to support broadband of up to 100 MHz, and for this purpose, carrier aggregation (or carrier aggregation) or bandwidth aggregation (or bandwidth aggregation) (which achieves broadband using multiple frequency blocks) ( carrier aggregation or bandwidth aggregation) technology is used. Carrier aggregation allows the use of multiple frequency blocks as one large logical frequency band to use a wider frequency band. The bandwidth of each frequency block may be defined based on the bandwidth of the system block used in the LTE system. Each frequency block is transmitted using a component carrier.

As carrier aggregation technology is adopted in the LTE-A system, which is a next-generation communication system, a method for a terminal to receive a signal from a base station or a repeater in a system supporting a plurality of carriers is required.

It is an object of the present invention to provide a method and apparatus for transmitting data by determining a cross-carrier scheduled uplink component carrier using a carrier indicator field (CIF) included in downlink control information (DCI).

The present invention provides a method of operating a terminal for transmitting a data burst through cross-carrier scheduling in a system supporting a plurality of component carriers, the downlink control channel (PDCCH) in the control region in the sub-frame Receiving, from the base station, downlink control information (DCI) including a carrier indicator field (CIF); Identifying a downlink component carrier indicated by the carrier indicator field, and then determining an uplink component carrier for which the identified downlink component carrier and linkage are set; And transmitting an uplink data burst to the base station through the determined uplink component carrier.

The carrier indicator field may indicate an index value indicating each component carrier according to a component carrier configuration allocated to the terminal.

The carrier indicator field may be an index value indicating a downlink component carrier.

The downlink control information may be a downlink scheduling assignment including downlink resource allocation information or an uplink grant including uplink resource allocation information.

In addition, the identified downlink component carrier is characterized in that the downlink component carrier is configured with at least one uplink component carrier and linkage.

In addition, the carrier indicator field is characterized in that represented by 3 bits.

The present invention also provides a terminal for transmitting a data burst through cross-carrier scheduling in a system supporting a plurality of component carriers, the terminal comprising: a wireless communication unit for transmitting and receiving a radio signal; And a control unit connected to the wireless communication unit, wherein the control unit transmits downlink control information (DCI) including a carrier indicator field (CIF) from a base station through a downlink control channel (PDCCH) in a control region within a subframe. And control the wireless communication unit to receive the downlink component carrier indicated by the carrier indicator field, determine the uplink component carrier to which the identified downlink component carrier and linkage are set, and determine the determined uplink component carrier. And controlling the wireless communication unit to transmit an uplink data burst to the base station through.

The present invention uses a UE-specific carrier indicator field (CIF), that is, by indexing each component carriers according to the component carrier configuration assigned to each terminal and informs the indexing value to the CIF, There is an effect that can schedule all terminals with a CIF of a fixed size.

Effects obtained in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

1 is a view for explaining a physical channel used in the 3GPP system and a general signal transmission method using the same.

2 is a diagram illustrating a structure of a radio frame used in a 3GPP LTE system that is an example of a mobile communication system.

3 (a) is a diagram showing a structure of a downlink subframe of a 3GPP LTE system which is an example of a mobile communication system.

3 (b) is a view showing a structure of an uplink subframe of a 3GPP LTE system which is an example of a mobile communication system.

4 illustrates a downlink time-frequency resource grid structure used in the present invention.

5 is a block diagram showing a configuration of a PDCCH.

6 illustrates an example of resource mapping of a PDCCH.

7 illustrates CCE interleaving in the system band.

8 is an exemplary diagram illustrating monitoring of a PDCCH.

FIG. 9A illustrates a concept of managing multiple carriers by multiple MACs in a base station, and FIG. 9B illustrates a concept of managing multiple carriers by multiple MACs in a terminal.

FIG. 10A is a diagram for describing a concept in which a single MAC manages a multicarrier in a base station, and FIG. 10B is a view for explaining a concept in which a single MAC manages a multicarrier in a terminal. .

11 illustrates an example of a multicarrier.

12 illustrates an example of cross-carrier scheduling.

13 illustrates an example of a component carrier (CC) set.

FIG. 14A illustrates a method of establishing a cell-specific carrier indicator field (CIF). FIG.

14 (b) is a diagram illustrating a UE-specific CIF setting method according to an embodiment of the present invention.

15 is a block diagram showing a wireless communication system according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details. For example, the following detailed description will be described in detail on the assumption that the mobile communication system is a 3GPP LTE, LTE-A system, but is also applied to any other mobile communication system except for the specific matters of the 3GPP LTE, LTE-A. Applicable

In some instances, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices in order to avoid obscuring the concepts of the present invention. In addition, the same components will be described with the same reference numerals throughout the present specification.

In addition, in the following description, it is assumed that a terminal collectively refers to a mobile or fixed user terminal device such as a user equipment (UE), a mobile station (MS), and an advanced mobile station (AMS). In addition, it is assumed that the base station collectively refers to any node of the network side that communicates with the terminal such as a Node B, an eNode B, a Base Station, and an Access Point (AP). The repeater may be referred to as a relay node (RN), a relay station (RS), a relay, or the like.

In a mobile communication system, a user equipment and a repeater may receive information from a base station through downlink, and the terminal and repeater may also transmit information through uplink. The information transmitted or received by the terminal and the repeater includes data and various control information, and various physical channels exist according to the type and purpose of the information transmitted or received by the terminal and the repeater.

FIG. 1 is a diagram for explaining physical channels used in a 3GPP system and a general signal transmission method using the same.

When the UE is powered on or enters a new cell, the UE performs an initial cell search operation such as synchronizing with the base station (S101). To this end, the terminal may receive a Primary Synchronization Channel (P-SCH) and a Secondary Synchronization Channel (S-SCH) from the base station to synchronize with the base station and obtain information such as a cell ID. have. Thereafter, the terminal may receive a physical broadcast channel from the base station to obtain broadcast information in a cell. Meanwhile, the terminal may receive a downlink reference signal (DL RS) in the initial cell search step to check the downlink channel state.

Upon completion of the initial cell search, the UE obtains more specific system information by receiving a physical downlink control channel (PDCCH) and a physical downlink control channel (PDSCH) according to the information on the PDCCH. It may be (S102).

On the other hand, when the first access to the base station or there is no radio resource for signal transmission, the terminal may perform a random access procedure (RACH) for the base station (steps S103 to S106). To this end, the UE may transmit a specific sequence as a preamble through a physical random access channel (PRACH) (S103 and S105), and receive a response message for the preamble through the PDCCH and the corresponding PDSCH ( S104 and S106). In the case of contention-based RACH, a contention resolution procedure may be additionally performed.

After performing the procedure described above, the UE performs a PDCCH / PDSCH reception (S107) and a physical uplink shared channel (PUSCH) / physical uplink control channel (Physical Uplink) as a general uplink / downlink signal transmission procedure. Control Channel (PUCCH) transmission (S108) may be performed. Information transmitted by the terminal to the base station through the uplink or received by the terminal from the base station includes a downlink / uplink ACK / NACK signal, a channel quality indicator (CQI), a precoding matrix index (PMI), and a rank indicator (RI). Include. In the 3GPP LTE system, the terminal may transmit the above-described information, such as CQI / PMI / RI through the PUSCH and / or PUCCH.

2 is a diagram illustrating a structure of a radio frame used in a 3GPP LTE system as an example of a mobile communication system.

Referring to FIG. 2, one radio frame has a length of 10 ms (327200 Ts) and consists of 10 equally sized subframes. Each subframe has a length of 1 ms and consists of two slots. Each slot has a length of 0.5 ms (15360 Ts). Here, Ts represents a sampling time and is represented by Ts = 1 / (15 kHz x 2048) = 3.1552 x 10 ^-8 (about 33 ns). The slot includes a plurality of OFDM symbols or SC-FDMA symbols in the time domain and a plurality of resource blocks in the frequency domain.

In an LTE system, one resource block (RB) includes 12 subcarriers x 7 (6) OFDM symbols or a SC-FDMA (Single Carrier-Frequency Division Multiple Access) symbol. Transmission time interval (TTI), which is a unit time for transmitting data, may be determined in units of one or more subframes. The structure of the above-described radio frame is only an example, and the number of subframes included in the radio frame or the number of slots included in the subframe, the number of OFDM symbols or SC-FDMA symbols included in the slot may be variously changed. have.

3 is a diagram illustrating a structure of downlink and uplink subframes of a 3GPP LTE system as an example of a mobile communication system.

Referring to FIG. 3A, one downlink subframe includes two slots in the time domain. Up to three OFDM symbols of the first slot in the downlink subframe are control regions to which control channels are allocated, and the remaining OFDM symbols are data regions to which a Physical Downlink Shared Channel (PDSCH) is allocated.

Downlink control channels used in 3GPP LTE systems include a PCFICH (Physical Control Format Indicator Channel), PDCCH (Physical Downlink Control Channel), PHICH (Physical Hybrid-ARQ Indicator Channel). The PCFICH transmitted in the first OFDM symbol of the subframe carries information about the number of OFDM symbols (that is, the size of the control region) used for transmission of control channels in the subframe. Control information transmitted through the PDCCH is called downlink control information (DCI). DCI indicates uplink resource allocation information, downlink resource allocation information, and uplink transmission power control command for arbitrary UE groups. The PHICH carries an ACK (Acknowledgement) / NACK (Not-Acknowledgement) signal for an uplink HARQ (Hybrid Automatic Repeat Request). That is, the ACK / NACK signal for the uplink data transmitted by the terminal is transmitted on the PHICH.

Hereinafter, the PDCCH which is a downlink physical channel will be briefly described. A detailed description of the PDCCH will be described below with reference to FIGS. 5 to 8.

The base station sets a resource allocation and transmission format of the PDSCH (also referred to as a DL grant), a resource allocation information of the PUSCH (also referred to as a UL grant) through a PDCCH, a set of transmission power control commands for an arbitrary terminal and individual terminals in a group. And activation of Voice over Internet Protocol (VoIP). A plurality of PDCCHs may be transmitted in the control region, and the terminal may monitor the plurality of PDCCHs. The PDCCH consists of an aggregation of one or several consecutive Control Channel Elements (CCEs).

The PDCCH composed of one or several consecutive CCEs may be transmitted through the control region after subblock interleaving. CCE is a logical allocation unit used to provide a PDCCH with a coding rate according to a state of a radio channel. The CCE corresponds to a plurality of resource element groups. The format of the PDCCH and the number of possible bits of the PDCCH are determined by the correlation between the number of CCEs and the coding rate provided by the CCEs.

Control information transmitted through the PDCCH is called downlink control information (DCI). Table 1 below shows DCI according to DCI format.

Table 1

DCI format 0 indicates uplink resource allocation information, DCI formats 1 to 2 indicate downlink resource allocation information, and DCI formats 3 and 3A indicate uplink transmit power control (TPC) commands for arbitrary UE groups. .

In the LTE system, a brief description will be given of a method for mapping a resource for transmitting a PDCCH by a base station.

In general, the base station may transmit scheduling assignment information and other control information through the PDCCH. The physical control channel may be transmitted in one aggregation or a plurality of continuous control channel elements (CCEs). One CCE includes nine Resource Element Groups (REGs). The number of RBGs that are not allocated to the Physical Control Format Indicator CHhannel (PCFICH) or the Physical Hybrid Automatic Repeat Request Indicator Channel (PHICH) is N _REG . The available CCEs in the system are from 0 to N _CCE -1 (where

to be). The PDCCH supports multiple formats as shown in Table 3 below. One PDCCH composed of n consecutive CCEs starts with a CCE that performs i mod n = 0 (where i is a CCE number). Multiple PDCCHs may be transmitted in one subframe.

TABLE 2

Referring to Table 2, the base station may determine the PDCCH format according to how many areas, such as control information, to send. The UE may reduce overhead by reading control information in units of CCE. Similarly, the repeater can also read control information and the like in units of R-CCE. In the LTE-A system, a resource element (RE) may be mapped in units of a relay-control channel element (R-CCE) to transmit an R-PDCCH for an arbitrary repeater.

Referring to FIG. 3B, an uplink subframe may be divided into a control region and a data region in the frequency domain. The control region is allocated to a physical uplink control channel (PUCCH) that carries uplink control information. The data area is allocated to a Physical Uplink Shared CHannel (PUSCH) for carrying user data. In order to maintain a single carrier characteristic, one UE does not simultaneously transmit a PUCCH and a PUSCH. PUCCH for one UE is allocated to an RB pair in one subframe. RBs belonging to the RB pair occupy different subcarriers in each of two slots. The RB pair assigned to the PUCCH is frequency hopped at the slot boundary.

4 illustrates a downlink time-frequency resource grid structure used in the present invention.

The downlink signal transmitted in each slot

Subcarriers and

It is used as a resource grid structure composed of orthogonal frequency division multiplexing (OFDM) symbols. here,

Represents the number of resource blocks (RBs) in downlink,

Represents the number of subcarriers constituting one RB,

Denotes the number of OFDM symbols in one downlink slot.

The size of depends on the downlink transmission bandwidth configured within the cell.

Must be satisfied. here,

Is the smallest downlink bandwidth supported by the wireless communication system.

Is the largest downlink bandwidth supported by the wireless communication system.

= 6

= 110, but is not limited thereto. The number of OFDM symbols included in one slot may vary depending on the length of a cyclic prefix (CP) and the interval of subcarriers. In case of multi-antenna transmission, one resource grid may be defined per one antenna port.

Each element in the resource grid for each antenna port is called a resource element (RE) and is uniquely identified by an index pair (k, l) in the slot. Where k is the index in the frequency domain, l is the index in the time domain and k is 0, ...,

Has any one of the values l is 0, ...,

Has any one of the values.

The resource block shown in FIG. 4 is used to describe a mapping relationship between certain physical channels and resource elements. The RB may be divided into a physical resource block (PRB) and a virtual resource block (VRB). The one PRB is a time domain

Contiguous OFDM symbols and frequency domain

It is defined as two consecutive subcarriers. here

and

May be a predetermined value. E.g

and

Can be given as Table 1 below. So one PRB

It consists of four resource elements. One PRB may correspond to one slot in the time domain and 180 kHz in the frequency domain, but is not limited thereto.

TABLE 3

PRB is at 0 in the frequency domain

Has a value up to. The relation between the PRB number nPRB in the frequency domain and the resource element (k, l) in one slot is

Satisfies.

The size of the VRB is equal to the size of the PRB. The VRB may be defined by being divided into a localized VRB (LVRB) and a distributed VRB (DVRB). For each type of VRB, a pair of VRBs in two slots in one subframe are assigned together a single VRB number n _VRBs .

The VRB may have the same size as the PRB. Two types of VRBs are defined, the first type being a localized VRB (LVRB) and the second type being a distributed VRB (DVRB). For each type of VRB, a pair of VRBs are allocated over two slots of one subframe with a single VRB index (hereinafter may also be referred to as VRB number). In other words, belonging to the first slot of the two slots constituting one subframe

VRBs from 0 each

Is assigned an index of any one of the two slots

VRBs likewise start with 0

Any one of the indexes is allocated.

As described above, the radio frame structure, the downlink subframe and the uplink subframe, and the downlink time-frequency resource lattice structure described in FIGS. 2 to 4 may also be applied between the base station and the repeater.

Hereinafter, a process for sending a PDCCH to a terminal by a base station in an LTE system will be described.

5 is a block diagram showing the configuration of a PDCCH.

The base station determines the PDCCH format according to the DCI to be sent to the terminal, attaches a cyclic redundancy check (CRC) to the DCI, and unique identifier according to the owner or purpose of the PDCCH (this is called a Radio Network Temporary Identifier) Mask the CRC (510).

If the PDCCH is for a specific terminal, a unique identifier of the terminal, for example, a C-RNTI (Cell-RNTI) may be masked to the CRC. Alternatively, if the PDCCH is for a paging message, a paging indication identifier, for example, P-RNTI (P-RNTI), may be masked to the CRC. If it is a PDCCH for system information, a system information identifier and a system information-RNTI (SI-RNTI) may be masked to the CRC. A random access-RNTI (RARNTI) may be masked to the CRC to indicate a random access response that is a response to the transmission of the random access preamble of the UE. TPC-RNTI may be masked to the CRC to indicate a transmit power control (TPC) command for a plurality of terminals.

If the C-RNTI is used, the PDCCH carries control information for the corresponding specific UE (called UE-specific control information), and if another RNTI is used, the PDCCH is shared by all or a plurality of terminals in the cell. (common) carries control information.

The DCC added with the CRC is encoded to generate coded data (520). Encoding includes channel encoding and rate matching.

The coded data is modulated to generate modulation symbols (530).

The modulation symbols are mapped to a physical resource element (RE) (540). Each modulation symbol is mapped to an RE.

6 shows an example of resource mapping of a PDCCH.

Referring to FIG. 6, R0 represents a reference signal of the first antenna, R1 represents a reference signal of the second antenna, R2 represents a reference signal of the third antenna, and R3 represents a reference signal of the fourth antenna.

The control region in the subframe includes a plurality of control channel elements (CCEs). The CCE is a logical allocation unit used to provide a coding rate according to the state of a radio channel to a PDCCH and corresponds to a plurality of resource element groups (REGs). The REG includes a plurality of resource elements. The format of the PDCCH and the number of bits of the PDCCH are determined according to the correlation between the number of CCEs and the coding rate provided by the CCEs.

One REG (denoted as quadruplet in the figure) contains four REs and one CCE contains nine REGs. {1, 2, 4, 8} CCEs may be used to configure one PDCCH, and each element of {1, 2, 4, 8} is called a CCE aggregation level.

A control channel composed of one or more CCEs performs interleaving in units of REGs and is mapped to physical resources after a cyclic shift based on a cell ID.

7 shows an example of distributing CCEs in a system band.

Referring to FIG. 7, a plurality of logically continuous CCEs are input to an interleaver. The interleaver performs a function of mixing input CCEs in REG units.

Accordingly, frequency / time resources constituting one CCE are physically dispersed in the entire frequency / time domain in the control region of the subframe. As a result, the control channel is configured in units of CCE, but interleaving is performed in units of REGs, thereby maximizing frequency diversity and interference randomization gain.

8 is an exemplary diagram illustrating monitoring of a PDCCH.

In 3GPP LTE, blind decoding is used to detect the PDCCH. Blind decoding is a method of demasking a desired identifier in a CRC of a received PDCCH (which is called a PDCCH candidate), and checking a CRC error to determine whether the corresponding PDCCH is its control channel. The UE does not know where its PDCCH is transmitted using which CCE aggregation level or DCI format at which position in the control region.

A plurality of PDCCHs may be transmitted in one subframe. The UE monitors the plurality of PDCCHs in every subframe. In this case, the monitoring means that the UE attempts to decode the PDCCH according to the monitored PDCCH format.

In 3GPP LTE, a search space is used to reduce the burden of blind decoding. The search space may be referred to as a monitoring set of the CCE for the PDCCH. The UE monitors the PDCCH in the corresponding search space.

The search space is divided into a common search space and a UE-specific search space. The common search space is a space for searching for a PDCCH having common control information. The common search space includes 16 CCEs up to CCE indexes 0 to 15 and supports a PDCCH having a CCE aggregation level of {4, 8}. However, PDCCHs (DCI formats 0 and 1A) carrying UE specific information may also be transmitted in the common search space. The UE-specific search space supports a PDCCH having a CCE aggregation level of {1, 2, 4, 8}.

Table 4 below shows the number of PDCCH candidates monitored by the UE.

Table 4

The size of the search space is determined by Table 4, and the starting point of the search space is defined differently from the common search space and the terminal specific search space. The starting point of the common search space is fixed irrespective of the subframe, but the starting point of the UE-specific search space is for each subframe according to the terminal identifier (eg, C-RNTI), the CCE aggregation level and / or the slot number in the radio frame. Can vary. When the start point of the terminal specific search space is in the common search space, the terminal specific search space and the common search space may overlap.

At the aggregation level L '{1,2,3,4}, the search space S (L) k is defined as a set of PDCCH candidates. The CCE corresponding to the PDCCH candidate m in the search space S ^(L) _k is given as follows.

Equation 1

Where i = 0,1, ..., L-1, m = 0, ..., M ^(L) -1, N _{CCE, k} can be used for transmission of the PDCCH in the control region of subframe k. The total number of CCEs present. The control region includes a set of CCEs numbered from 0 to N _{CCE, k} −1. M ^(L) is the number of PDCCH candidates at CCE aggregation level L in a given search space. In the common search space, Y _k is set to zero for two aggregation levels, L = 4 and L = 8. In the UE-specific search space of the aggregation level L, the variable Y _k is defined as follows.

Equation 2

Where Y ₋₁ = n _RNTI ≠ 0, A = 39827, D = 65537, k = floor (n _s / 2), n _s is a slot number in a radio frame.

When the UE monitors the PDCCH using the C-RNTI, a DCI format and a search space to be monitored are determined according to a transmission mode of the PDSCH.

Table 5 below shows an example of PDCCH monitoring configured with C-RNTI.

Table 5

Hereinafter, a multiple carrier system will be described.

The 3GPP LTE system supports a case where the downlink bandwidth and the uplink bandwidth are set differently, but this assumes one component carrier (CC).

This means that 3GPP LTE is supported only when the bandwidth of the downlink and the bandwidth of the uplink are the same or different in the situation where one CC is defined for the downlink and the uplink, respectively. For example, the 3GPP LTE system supports up to 20MHz and may be different in uplink bandwidth and downlink bandwidth, but only one CC is supported in the uplink and the downlink.

Spectrum aggregation (or bandwidth aggregation, also known as carrier aggregation) supports a plurality of CCs. Spectral aggregation is introduced to support increased throughput, to prevent cost increases due to the introduction of wideband radio frequency (RF) devices, and to ensure compatibility with existing systems. For example, if five CCs are allocated as granularity in a carrier unit having a 20 MHz bandwidth, a bandwidth of up to 100 MHz may be supported.

Spectral aggregation can be divided into contiguous spectral aggregation where aggregation is between successive carriers in the frequency domain and non-contiguous spectral aggregation where aggregation is between discontinuous carriers. The number of CCs 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 downlink component carrier and the uplink component carrier may be collectively referred to as a 'cell'. That is, 'cell' may be used as a concept for a pair of DL CC and UL CC. Here, the term 'cell' should be distinguished from the term 'cell' as an area covered by a generally used base station.

The size (ie bandwidth) of the CC may be different. For example, assuming that 5 CCs are used to configure a 70 MHz band, a 5 MHz carrier (CC # 0) + 20 MHz carrier (CC # 1) + 20 MHz carrier (CC # 2) + 20 MHz carrier (CC # 3) It may also be configured as a + 5MHz carrier (CC # 4).

The configuration of a physical layer (PHY) and layer 2 (layer 2 (MAC)) for transmission for a plurality of uplink or downlink carrier bands allocated from the point of view of any cell or terminal is shown in FIG. 9. And as shown in FIG. 10.

FIG. 9A illustrates a concept of managing a multicarrier by a plurality of MACs in a base station, and FIG. 9B illustrates a concept of managing a multicarrier by a plurality of MACs in a terminal.

As shown in (a) and (b) of FIG. 9, each carrier may control 1: 1 by each MAC. In a system supporting multiple carriers, each carrier may be used contiguously or non-contiguous. This can be applied to the uplink / downlink irrespective. The TDD system is configured to operate N multiple carriers including downlink and uplink transmission in each carrier, and the FDD system is configured to use multiple carriers for uplink and downlink, respectively. In the case of the FDD system, asymmetric carrier merging may be supported in which the number of carriers and / or the bandwidth of the carriers are merged in uplink and downlink.

FIG. 10 (a) is a diagram for explaining a concept of managing a multicarrier by one MAC in a base station, and FIG. 10 (b) is a diagram for explaining a concept in which one MAC manages a multicarrier in a terminal. .

Referring to (a) and (b) of FIG. 10, one MAC manages and operates one or more frequency carriers to perform transmission and reception. Frequency carriers managed in one MAC do not need to be contiguous with each other, which is advantageous in terms of resource management. In (a) and (b) of FIG. 10, one PHY means one component carrier for convenience. Here, one PHY does not necessarily mean an independent radio frequency (RF) device. In general, one independent RF device means one PHY, but is not limited thereto, and one RF device may include several PHYs.

In addition, a series of physical downlink control channels for transmitting control information of L1 / L2 control signaling generated from the packet scheduler of the MAC layer to support the configuration of FIGS. 10A and 10B. channel, PDCCH) may be transmitted by mapping to a physical resource in an individual component carrier.

In this case, in particular, the PDCCH for channel allocation or grant-related control information related to PDSCH or PUSCH (Physical Uplink Shared Channel) transmission unique to each UE is classified and encoded according to component carriers to which the corresponding physical shared channel is transmitted. It can be generated as a PDCCH. This is referred to as separate coded PDCCH. Alternatively, control information for physical shared channel transmission of various component carriers may be configured and transmitted as one PDCCH, which is referred to as a joint coded PDCCH.

In order to support downlink or uplink carrier aggregation, a base station is configured such that a PDCCH and / or PDSCH for transmitting control information and / or data transmission can be transmitted uniquely for a specific terminal or repeater, or the PDCCH And / or component carriers that are subject to measurement and / or reporting as preparation for performing connection establishment for PDSCH transmission. This is expressed as component carrier allocation for any purpose.

In this case, when the base station controls the component carrier allocation information in the L3 RRM (radio resource management), the RRC signaling (terminal-specific or repeater-specific RRC signaling) unique to a series of terminals or repeaters according to dynamic characteristics of the control (dynamic) It may be transmitted through the L1 / L2 control signaling or through a series of PDCCHs or through a series of dedicated physical control channels for transmitting only this control information.

11 shows an example of a multicarrier.

Although there are three DL CCs and three UL CCs, the number of DL CCs and UL CCs is not limited. PDCCH and PDSCH are independently transmitted in each DL CC, and PUCCH and PUSCH are independently transmitted in each UL CC.

Hereinafter, a multiple carrier system refers to a system supporting multiple carriers based on spectral aggregation, as described above.

Adjacent spectral and / or non-adjacent spectral aggregation may be used in a multi-carrier system, and either symmetric or asymmetric aggregation may be used.

In a multi-carrier system, linkage between a DL CC and a UL CC may be defined. The linkage may be configured through EARFCN information included in the downlink system information, and is configured using a fixed DL / UL Tx / Rx separation relationship. The linkage refers to a mapping relationship between a DL CC through which a PDCCH carrying an UL grant is transmitted and a UL CC using the UL grant.

Alternatively, the linkage may be a mapping relationship between a DL CC (or UL CC) in which data for HARQ is transmitted and a UL CC (or DL CC) in which HARQ ACK / NACK signal is transmitted. The linkage information may be informed to the terminal by the base station as part of a higher layer message or system information such as an RRC message. The linkage between the DL CC and the UL CC may be fixed but may be changed between cells / terminals.

The split coded PDCCH means that the PDCCH can carry control information such as resource allocation for PDSCH / PUSCH for one carrier. That is, the PDCCH and PDSCH, the PDCCH and the PUSCH correspond to 1: 1 respectively.

A joint coded PDCCH means that one PDCCH can carry resource allocation for PDSCH / PUSCH of a plurality of CCs. One PDCCH may be transmitted through one CC or may be transmitted through a plurality of CCs.

Hereinafter, for convenience, an example of split coding will be described based on the downlink channel PDSCH-PDSCH. However, this may also be applied to the relationship of PDCCH-PUSCH.

In a multi-carrier system, CC scheduling is possible in two ways.

The first is that a PDCCH-PDSCH pair is transmitted in one CC. This CC is called a self-secheduling CC. In addition, this means that the UL CC on which the PUSCH is transmitted becomes the CC linked to the DL CC on which the corresponding PDCCH is transmitted.

That is, the PDCCH allocates PDSCH resources on the same CC or allocates PUSCH resources on a linked UL CC.

Second, regardless of the DL CC on which the PDCCH is transmitted, the DL CC on which the PDSCH is transmitted or the UL CC on which the PUSCH is transmitted is determined. That is, the PUSCH is transmitted on a DL CC in which the PDCCH and the PDSCH are different from each other, or on a UL CC not linked with the DL CC in which the PDCCH is transmitted. This is called cross-carrier scheduling.

The CC on which the PDCCH is transmitted may be referred to as a PDCCH carrier, a monitoring carrier, or a scheduling carrier, and the CC on which the PDSCH / PUSCH is transmitted may be referred to as a PDSCH / PUSCH carrier or a scheduled carrier.

Cross-carrier scheduling may be activated / deactivated for each terminal, and the terminal on which cross-carrier scheduling is activated may receive a DCI including CIF. The UE may know which scheduled CC the PDCCH received from the CIF included in the DCI is control information.

The DL-UL linkage predefined by cross-carrier scheduling may be overriding. That is, cross-carrier scheduling may schedule a CC other than the linked CC regardless of the DL-UL linkage.

12 shows an example of cross-carrier scheduling.

It is assumed that DL CC # 1 and UL CC # 1 are linked, DL CC # 2 and UL CC # 2 are linked, and DL CC # 3 and UL CC # 3 are linked.

The first PDCCH 1201 of the DL CC # 1 carries the DCI for the PDSCH 1202 of the same DL CC # 1. The second PDCCH 1211 of the DL CC # 1 carries the DCI for the PDSCH 1212 of the DL CC # 2. The third PDCCH 1221 of the DL CC # 1 carries the DCI for the PUSCH 1222 of the UL CC # 3 that is not linked.

For cross-carrier scheduling, the DCI of the PDCCH may include a carrier indicator field (CIF). CIF indicates a DL CC or UL CC scheduled through DCI. For example, the second PDCCH 1211 may include a CIF indicating DL CC # 2. The third PDCCH 1221 may include a CIF indicating the UL CC # 3.

Alternatively, the CIF of the third PDCCH 1221 may be informed by the CIF value corresponding to the DL CC, not the CIF value corresponding to the UL CC.

That is, the CIF of the third PDCCH 1221 indicates the DL CC # 3 linked with the UL CC # 3, so that the PUSCH may indirectly indicate the scheduled UL CC # 3. This is because if the DCI of the PDCCH includes the PUSCH scheduling and the CIF indicates the DL CC, the UE may determine that the PUSCH is scheduled on the UL CC linked with the DL CC. Through this, it is possible to indicate a larger number of CCs than a method of notifying all DL / UL CCs using a CIF having a limited bit length (for example, 3 bit length CIF).

A UE using cross-carrier scheduling needs to monitor PDCCHs of a plurality of scheduled CCs for the same DCI format in a control region of one scheduling CC. For example, if a transmission mode of each of the plurality of DL CCs is different, a plurality of PDCCHs for different DCI formats may be monitored in each DL CC. Same transfer mode

Even if used, if the bandwidth of each DL CC is different, a plurality of PDCCHs can be monitored because the payload size of the DCI format is different under the same DCI format.

As a result, when cross-carrier scheduling is possible, the UE needs to monitor PDCCHs for the plurality of DCIs in the control region of the monitoring CC according to the transmission mode and / or bandwidth for each CC. Therefore, it is necessary to configure the search space and PDCCH monitoring that can support this.

First, in the multi-carrier system, the following terms are defined.

UE DL CC set: a set of DL CCs scheduled for the UE to receive PDSCH

UE UL CC set: a set of UL CCs scheduled for the UE to transmit a PUSCH

PDCCH monitoring set: A set of at least one DL CC that performs PDCCH monitoring. The PDCCH monitoring set may be the same as the UE DL CC set or may be a subset of the UE DL CC set. The PDCCH monitoring set may include at least one of DL CCs in the UE DL CC set. Alternatively, the PDCCH monitoring set may be defined separately regardless of the UE DL CC set. The DL CC included in the PDCCH monitoring set may be configured to always enable self-scheduling for the linked UL CC.

The UE DL CC set, the UE UL CC set, and the PDCCH monitoring set may be set to cell-specific or UE-specific.

13 shows an example of a CC set. 4 DL CCs (DL CC # 1, # 2, # 3, # 4) as UE DL CC set, 2 UL CCs (UL CC # 1, # 2) as UE UL CC set, DL CC as PDCCH monitoring set Assume that two (DL CC # 2, # 3) are allocated to the terminal.

The DL CC # 2 in the PDCCH monitoring set transmits the PDCCH for the PDSCH of the DL CC # 1 / # 2 in the UE DL CC set and the PDCCH for the PUSCH of the UL CC # 1 in the UE UL CC set. The DL CC # 3 in the PDCCH monitoring set transmits the PDCCH for the PDSCH of the DL CC # 3 / # 4 in the UE DL CC set and the PDCCH for the PUSCH of the UL CC # 2 in the UE UL CC set.

Linkage may be set between CCs included in the UE DL CC set, the UE UL CC set, and the PDCCH monitoring set. In the example of FIG. 13, a PDCCH-PDSCH linkage is configured between DL CC # 2 which is a scheduling CC and DL CC # 1 which is a scheduled CC, and a PDCCH-PUSCH linkage is configured for DL CC # 2 and UL CC # 1. In addition, the PDCCH-PDSCH linkage is set between the DL CC # 3 which is the scheduling CC and the DL CC # 4 which is the scheduled CC, and the PDCCH-PUSCH linkage is set for the DL CC # 3 and the UL CC # 2. The information about the scheduling CC or the PDCCH-PDSCH / PUSCH linkage information may be informed by the base station to the terminal through cell-specific signaling or terminal-specific signaling.

Alternatively, both the DL CC and the UL CC may not be linked to each of the DL CCs in the PDCCH monitoring set. After linking the DL CC in the PDCCH monitoring set and the DL CC in the UE DL CC set, the UL CC for PUSCH transmission may be limited to the UL CC linked to the DL CC in the UE DL CC set.

The CIF may be set differently according to linkages of the UE DL CC set, the UE UL CC set, and the PDCCH monitoring set.

Hereinafter, when a carrier indication field (CIF) is received from a base station in a cross-carrier scheduling enabled terminal according to an embodiment of the present invention, a method of interpreting the CIF will be described.

First, before describing the CIF interpretation method according to an embodiment of the present invention, a brief description of a cell-specific carrier indicator field (CIF) configuration method and a UE-specific CIF configuration method Let's explain.

14 is a diagram illustrating a CIF setting method.

FIG. 14A illustrates a cell-specific carrier indicator field (CIF) setting method, and FIG. 14B illustrates a UE-specific CIF setting method.

As shown in FIG. 14A, a cell-specific CIF method indexes all component carriers (CCs) configured in a specific cell, and indicates an index value corresponding to the CC to each UE. will be.

Referring to FIG. 14A, when there are 5 CCs configured in a cell from CC0 to CC4, the CCs are indexed as '000', '001', '010', '100', and '101' for each CC. The indexing value is reported to the CIF.

Here, the CIF is fixed to 3 bits, whereas one cell can use cell deployment using more than 8 CCs that can be expressed as 3 bits, that is, 8 or more CCs. Therefore, cell-specific CIF indexing has the advantage that unified indexing can be used for all terminals, but it is impossible to properly schedule all terminals with only 3-bit CIF according to cell configuration.

In addition, as shown in FIG. 14B, the UE-specific CIF setting method refers to a method of indexing each CC according to a CC configuration allocated to each UE and notifying the corresponding indexing to the CIF.

Referring to FIG. 14B, component carrier configurations allocated to UE 0 are CC0, CC1, and CC3, and component carrier configurations allocated to UE 1 are CC1, CC2, and CC4.

Accordingly, the base station indexes CCO, CC1, and CC3 for UE 0 as '000', '001', and '010', and informs UE 0 of the indexing value as CIF. Further, the base station indexes CC1, CC2, and CC4 for UE 1 to '000', '001', and '010', respectively, and informs UE 1 of the indexing value as CIF.

Hereinafter, when a UE receives a CIF from a base station in a UE-specific CIF method, a method of interpreting the CIF will be described in detail.

Method 1: DL / UL independent CIF assignment

Method 1 is a method of independently allocating 3 bits of CIF to DL grants for DL CCs and 3 bits of CIF to UL grants for UL CCs. In the case of DCI format 0, which is the UL grant DCI format of LTE (Rel-8), since the size is always the same as the DCI format 1A, which is the DL grant DCI format, a flag corresponding to 1 bit is used to distinguish the DL / UL grant. Paste it.

That is, when eight states each of which can be represented by 3 bits from {000 to 111} are independently used for DL / UL, DL / UL cannot be distinguished because only CIF in DCI format can be distinguished from DL grant or UL grant. Add a flag to distinguish it.

Method 2: implicit UL CIF assignment

Method 2 is a method in which independent CIF is not transmitted to a UL grant for a UL CC.

(1) In case of performing cross-carrier scheduling with respect to UL grant, cross-carrier scheduling is activated by a user equipment. When receiving UL grant, the terminal is linked with DL CC which has received UL grant. Automatically recognize that the grant for the UL CC is transmitted to the UL CC that is linked with the DL CC.

(2) The indexing indicated by the CIF actually attached to the UL grant is sent to the indexing for the DL CC, and the terminal reads the corresponding CIF and automatically recognizes that it is a grant for the UL CC linked to the DL CC indicated by the CIF. Send data to CC. Here, the UE can know whether the DCI received from the base station is a DL grant or a UL grant through the size of the DCI fomat size.

Method 3: DL / UL combined CIF assignment

Method 3 is a method in which 3 states of CIF, that is, {000, 001, 010, 011, 100, 101, 110, 111}, are shared by DL / UL grant. For example, up to {000 ~ 100}, five states are used for the DL CC, and the remaining three states are used for the UL CC.

As in the above example, a DL CC and a UL CC may be used by fixing a state in which the DL / UL can be used. However, the CIF may be variably interpreted according to the carrier assignment state of the terminal.

For example, if UE A is assigned with four DL CCs and two UL CCs, four states of 000 to 011 are for indicating a DL CC, and two states for 100 to 101 are for indicating a UL CC. It can be interpreted as. In the above method, since the DL grant or the UL grant is distinguished by the state of the CIF, it is not necessary to attach a flag for distinguishing DL / UL like the method 1 above.

The above DL / UL DCI mode indicator is preferably present at a certain position, but as defined in the Rel-8 LTE system, the same position as the position where the DCI format indicator exists in DCI formats 0 and 1A is used as the position of the mode indicator. It is desirable to decide. By doing so, the DCI DL / UL mode can be consistently distinguished at a certain position regardless of the DCI mode.

In addition, when the DL / UL CC configuration in the hybrid form of the methods 1 to 3 falls within the range that can be expressed by the 3-bit CIF (that is, the total number of DL / UL CCs allocated to any UE does not exceed 8). E) uses the method 3 above, and if the DL / UL CC configuration is out of the range that can be represented by the 3-bit CIF (that is, the total number of DL / UL CC allocated to any terminal exceeds 8) ) Method 1 to Method 2 may be used.

That is, it is possible to use a method of varying the CIF interpretation according to the DL / UL CC configuration of the terminal.

According to the CC configuration of the terminal, the portion that can be changed for the CIF may be as follows.

1. Change of CIF interpretation method: As described above, it may be considered to change the mapping relationship between CIF and DL / UL CC. For example, when referring to CC with 3 bits of CIF, if the total number of DL CCs and UL CCs cannot be expressed as a state allowed for CC indexing in 3 bits, independent indexing is performed for DL CCs and UL CCs instead. It may include an indicator that specifies a DCI format. On the contrary, when the allowed state can be expressed, indexing by mixing DL / UL CC can be used to distinguish between DL DCI or UL DCI even when reporting only the value of CIF. In this case, it does not include DL / UL DCI mode separator. Can be determined. In this case, whether the DL / UL DCI mode indicator is present may be determined implicitly according to the CC configuration of the UE as described above, but may be explicitly set to UE-specific dedicated signaling together with the CC configuration.

Such determination criteria may vary depending on the UE-specific CC configuration, but may be determined according to the system-specific CC configuration. In other words, the UE may automatically set such an interpretation method according to the total number of CCs present in the system.

2. Change the meaning of CIF: You can change the mapping meaning of CIF depending on the total number of carriers in the system. In this case, the meaning may be a criterion for applying a CIF mapping method, that is, applying a UE-specific interpretation or selecting a cell-specific (system-specific interpretation).

That is, when the number of CCs present in the system can be expressed as an acceptable state of CIF, CIF is interpreted by system-specific indexing. Otherwise, CIF is interpreted UE-specific. That is, a method of mapping a value indicated by the CIF with a CC according to the UE-specific CC configuration.

The bit position occupied by the DCI format may vary depending on the presence or absence of a mode indicator. For example, if it is possible to know whether the DL DCI or UL DCI through the CIF, remove the position used as a mode indicator in the DCI format and concatenation the remaining fields to read the bit field, or the mode indicator is outside the DCI If defined, the terminal can read the DCI field by mapping the bit field after shifting by the position occupied by the mode indicator.

15 is a block diagram showing a wireless communication system according to an embodiment of the present invention.

The base station 1510 includes a controller 1511, a memory 1512, and a radio frequency unit (RF) unit 1513.

The controller 1511 implements the proposed function, process and / or method. Layers of the air interface protocol may be implemented by the controller 1511.

The controller 1511 may operate a multi-carrier and configure a carrier indicator field (CIF).

The memory 1512 is connected to the controller 1511 and stores protocols and parameters for multi-carrier operation. The RF unit 1513 is connected to the control unit 1511 and transmits and / or receives a radio signal.

The terminal 1520 includes a controller 1521, a memory 1522, and a radio communication (RF) unit 1523.

The controller 1521 implements the proposed function, process and / or method. Layers of the air interface protocol may be implemented by the controller 1521. The controller 1521 may operate a multi-carrier and use cross-carrier scheduling on the multi-carrier based on a carrier indicator field (CIF).

The memory 1512 is connected to the controller 1521 and stores a protocol or parameter for multi-carrier operation. The RF unit 1513 is connected to the control unit 1521 to transmit and / or receive a radio signal.

The controllers 1511 and 1521 may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, and / or a data processing device. The memories 1512 and 1522 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media and / or other storage devices. The RF unit 1513 and 1523 may include a baseband circuit for processing a radio signal. When the embodiment is implemented in software, the above-described technique may be implemented as a module (process, function, etc.) for performing the above-described function. The module may be stored in the memories 1512 and 1522 and executed by the controllers 1511 and 1521. The memories 1512 and 1522 may be inside or outside the controllers 1511 and 1521, and may be connected to the controllers 1511 and 1521 by various well-known means.

Claims (12)

1. A method of operating a terminal for transmitting data bursts through cross-carrier scheduling in a system supporting a plurality of component carriers,

   Receiving, from a base station, downlink control information (DCI) including a carrier indicator field (CIF) through a downlink control channel (PDCCH) in a control region within a subframe;

   Identifying a downlink component carrier indicated by the carrier indicator field, and then determining an uplink component carrier for which the identified downlink component carrier and linkage are set; And

   Transmitting an uplink data burst to the base station via the determined uplink component carrier.
2. The method of claim 1,

   The carrier indicator field is characterized in that the index (index) indicating each component carrier according to the component carrier configuration assigned to the terminal.
3. The method of claim 1,

   The carrier indicator field is an index value indicating a downlink component carrier.
4. The method of claim 1,

   The downlink control information may be a downlink scheduling assignment including downlink resource allocation information or an uplink grant including uplink resource allocation information.
5. The method of claim 1,

   The identified downlink component carrier is a downlink component carrier characterized in that the linkage is configured with at least one uplink component carrier.
6. The method of claim 1,

   And wherein the carrier indicator field is represented by three bits.
7. A terminal for transmitting a data burst through cross-carrier scheduling in a system supporting a plurality of component carriers,

   A wireless communication unit for transmitting and receiving a wireless signal; And

   Including a control unit connected to the wireless communication unit, The control unit,

   Controlling the wireless communication unit to receive downlink control information (DCI) including a carrier indicator field (CIF) from a base station through a downlink control channel (PDCCH) in a control region within a subframe,

   Identifying a downlink component carrier indicated by the carrier indicator field, and then determining an uplink component carrier configured with the identified downlink component carrier and linkage,

   And controlling the wireless communication unit to transmit an uplink data burst to the base station through the determined uplink component carrier.
8. The method of claim 7, wherein

   And the carrier indicator field indicates an index value indicating each component carrier according to a component carrier configuration allocated to the terminal.
9. The method of claim 7, wherein

   The downlink control information is a downlink scheduling assignment including DL resource assignment information or a UL grant including uplink resource allocation information.
10. The method of claim 7, wherein

    Wherein the carrier indicator field indicates a downlink component carrier on which a downlink data burst is transmitted.
11. The method of claim 7, wherein

    The carrier indicator field is characterized in that represented by three bits.
12. The method of claim 7, wherein

    And the carrier indicator field is an index value indicating a downlink component carrier.

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