WO2011162540A2

WO2011162540A2 - Method for transmitting response information to support plurality of component carriers in wireless communication system, and device therefor

Info

Publication number: WO2011162540A2
Application number: PCT/KR2011/004535
Authority: WO
Inventors: 이현우; 장지웅; 정재훈; 한승희
Original assignee: 엘지전자 주식회사
Priority date: 2010-06-22
Filing date: 2011-06-22
Publication date: 2011-12-29
Also published as: WO2011162540A3

Abstract

The present invention provides a method for allowing a terminal to transmit response information on component carriers in a wireless communication system that supports a plurality of component carriers, and a terminal device therefor. The method for transmitting the response information of the present invention comprises the steps of: receiving downlink data from a base station through each of a plurality of downlink resources; mapping response information on the plurality of downlink resources into a plurality of HARQ resources, by using either a first HARQ resource selection method or a second HARQ resource selection method; and transmitting said response information through the plurality of mapped HARQ resources, wherein each of said plurality of HARQ resources includes a reference signal region and a data signal region, said first HARQ resource selection method uses only the data signal region of each of the plurality of HARQ resources in order to identify said response information, and said second HARQ resource selection method uses the data signal region and the reference signal region of each of the plurality of HARQ resources in order to identify said response information.

Description

Method and apparatus for transmitting response information supporting a plurality of component carriers in wireless communication system

The present invention relates to a wireless communication system. Specifically, the present invention proposes a channel selection scheme for transmitting ACK / NACK for effectively supporting a plurality of component carriers in a mobile communication system.

As an example of a wireless communication system to which the present invention can be applied, a 3GPP LTE (3rd Generation Partnership Project Long Term Evolution (LTE)) communication system will be described.

1 is a diagram schematically illustrating an E-UMTS network structure as an example of a wireless communication system. The Evolved Universal Mobile Telecommunications System (E-UMTS) system is an evolution from the existing Universal Mobile Telecommunications System (UMTS), and is currently undergoing basic standardization in 3GPP. In general, the E-UMTS may be referred to as a Long Term Evolution (LTE) system. For details of the UMTS technical specification, refer to Release 7 of the "3rd Generation Partnership Project; Technical Specification Group Radio Access Network". For details of the technical specification of the E-UMTS, refer to Release 8 and Release 9 of the "3rd Generation Partnership Project; Technical Specification Group Radio Access Network".

Referring to FIG. 1, an E-UMTS is located at an end of a user equipment (UE) 120, a base station (eNode B; eNB) 110a and 110b, and a network (E-UTRAN) to be connected to an external network. Access Gateway (AG). The base station may transmit multiple data streams simultaneously for broadcast service, multicast service and / or unicast service.

One or more cells exist in one base station. The cell is set to one of the bandwidths of 1.4, 3, 5, 10, 15, 20Mhz, etc. to provide downlink or uplink transmission service to multiple terminals. Different cells may be configured to provide different bandwidths. The base station controls data transmission and reception for a plurality of terminals. For downlink (DL) data, the base station transmits downlink scheduling information to inform the corresponding UE of time / frequency domain, encoding, data size, and HARQ (Hybrid Automatic Repeat and reQuest) related information. In addition, the base station transmits uplink scheduling information to the terminal for uplink (UL) data and informs the user of the time / frequency domain, encoding, data size, HARQ-related information, etc. that the terminal can use. An interface for transmitting user traffic or control traffic may be used between base stations. The core network (CN) may be composed of an AG and a network node for user registration of the terminal. The AG manages the mobility of the UE in units of a tracking area (TA) composed of a plurality of cells.

Wireless communication technology has been developed to LTE based on WCDMA, but the demands and expectations of users and operators are continuously increasing. 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-Advanced" or "LTE-A". LTE-A is for defining a technical specification of Release 10 of the "3rd Generation Partnership Project; Technical Specification Group Radio Access Network". One of the major differences between LTE and LTE-A systems is the difference in system bandwidth. The LTE-A system aims to support broadband up to 100 MHz. To this end, LTE-A system is to use a carrier aggregation (carrier aggregation or bandwidth aggregation) technology that achieves a broadband by using a plurality of component carriers. Carrier aggregation allows a plurality of component carriers to be used as one large logical frequency band in order to use a wider frequency band. The bandwidth of each component carrier may be defined based on the bandwidth of the system block used in the LTE system. Each component carrier is transmitted using a component carrier.

Meanwhile, in the process of developing 3GPP LTE-A system, multiple component carriers (for example, carrier aggregation up to 100 MHz, support for up to five downlink component carriers, and up to five There is a discussion about a transmission / reception method using uplink component carriers, etc.). The existing LTE Rel-8 system is designed for single layer and single component carriers for downlink or uplink. There is a need for a method for effectively supporting such multiple component carriers and / or transport blocks and / or multiple codewords.

The present invention provides an efficient channel selection scheme for transmitting response information for effectively supporting a plurality of component carriers in a wireless communication system to which carrier aggregation is applied. Various channel selection schemes can be used according to the state of response information. It is to provide a method.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

In a wireless communication system, which is an aspect of the present invention, a method for transmitting response information by a terminal includes receiving downlink data from each of the plurality of downlink resources from a base station, and removing response information for the plurality of downlink resources. Mapping to a plurality of HARQ resources using any one of a 1 HARQ resource selection method or a second HARQ resource selection method, and transmitting the response information through the mapped plurality of HARQ resources. Each HARQ resource includes a reference signal area and a data signal area, and the first HARQ resource selection method uses only the data signal area of each of the plurality of HARQ resources to identify the response information, and the second HARQ resource. The selection scheme is a data signal region of each of the plurality of HARQ resources to identify the response information. And a reference signal region.

In the mapping to the plurality of HARQ resources, when the number of the plurality of downlink resources exceeds a first threshold, the response information is mapped to the plurality of HARQ resources using the second HARQ resource selection scheme. When the number of the plurality of downlink resources is less than or equal to a first threshold, the response information may be mapped to the plurality of HARQ resources by using the first HARQ resource selection method.

In the mapping to the plurality of HARQ resources, when the number of control signal bits to be transmitted through the response information exceeds a second threshold, the response information is mapped to the plurality of HARQ resources using the second HARQ resource selection scheme. When the number of control signal bits to be transmitted through the response information is less than or equal to a second threshold, the response information may be mapped to the plurality of HARQ resources by using the first HARQ resource selection method. The number of bits of the control signal to be transmitted through the response information is the number of downlink resources configured, the number of subframes in each downlink resource to be responded through the one response information, and the maximum supportable transmission block configured for each downlink resource. It is calculated by one or more of the number of (transport blocks).

The response information may include ACK / NACK information for the plurality of downlink resources.

When the response information is mapped in the second HARQ resource selection scheme, the plurality of HARQ resources to which the response information is mapped may be transmitted through one physical time / frequency resource.

In a wireless communication system according to another aspect of the present invention, a terminal for transmitting response information includes a receiver for receiving downlink data from each of the plurality of downlink resources from a base station, and receiving response information for the plurality of downlink resources from a first HARQ. A processor for mapping to a plurality of HARQ resources using any one of a resource selection method or a second HARQ resource selection method, and a transmitter for transmitting the response information through the mapped plurality of HARQ resources; Each resource includes a reference signal region and a data signal region, and the first HARQ resource selection scheme uses only the data signal region of each of the plurality of HARQ resources to identify the response information, and the second HARQ resource selection scheme. Is a data signal of each of the plurality of HARQ resources to identify the response information It can be used to reverse, and reference signal area.

According to embodiments of the present invention, the effect of minimizing the effect of the error of the signal by having to transmit the response information for a specific configuration carrier by selecting one of the different channel selection scheme in a wireless system using a multi-component carrier Is present.

The effects obtainable 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.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included as part of the detailed description in order to provide a thorough understanding of the present invention, provide examples of the present invention and together with the description, describe the technical idea of the present invention.

1 schematically illustrates an E-UMTS network structure as an example of a wireless communication system.

2 illustrates a block diagram of a transmitter and a receiver for OFDMA and SC-FDMA.

3 is a diagram illustrating the structure of a radio frame used in LTE.

4 illustrates an example of performing communication in a single component carrier situation.

5 illustrates the structure of an uplink subframe used in LTE.

6 illustrates a PUCCH structure for transmitting ACK / NACK.

7 is a diagram illustrating an example of determining a PUCCH resource for ACK / NACK signal transmission.

8 is a diagram illustrating an example of performing communication under a multi-carrier situation.

FIG. 9 is a diagram illustrating an operation of allocating response information using normal channel selection. FIG.

FIG. 10 is a diagram illustrating an operation of allocating response information using enhanced channel selection. FIG.

11 illustrates the flow of a complex channel selection scheme in accordance with the present invention.

12 is a diagram illustrating a base station and a terminal that can be applied to an embodiment in the present invention.

The construction, operation, and other features of the present invention will be readily understood by the embodiments of the present invention described with reference to the accompanying drawings. The embodiments described below are examples in which technical features of the present invention are applied to a 3GPP system.

Hereinafter, a system in which a system band uses a single component carrier is referred to as a legacy system or a narrowband system. Correspondingly, a system in which a system band includes a plurality of component carriers and uses at least one or more component carriers as a system block of a legacy system is referred to as an evolved system or a wideband system. The component carrier used as the legacy system block has the same size as the system block of the legacy system. On the other hand, the size of the remaining component carriers is not particularly limited. However, for system simplification, the size of the remaining component carriers may also be determined based on the system block size of the legacy system. For example, the 3GPP LTE system and the 3GPP LTE-A system are in a relationship between a legacy system and an evolved system.

Based on the above definition, the 3GPP LTE system is referred to herein as an LTE system or a legacy system. In addition, the terminal supporting the LTE system is referred to as an LTE terminal or a legacy terminal. Correspondingly, the 3GPP LTE-A system is referred to as LTE-A system or evolved system. In addition, a terminal supporting the LTE-A system is referred to as an LTE-A terminal or an evolved terminal.

For convenience, the present specification describes an embodiment of the present invention using an LTE system and an LTE-A system, but this is an example and the embodiment of the present invention can be applied to any communication system corresponding to the above definition.

2 is a diagram illustrating a block diagram of a transmitter and a receiver for OFDMA and SC-FDMA. In the uplink, transmitters 202-214 are terminals and receivers 216-230 are part of a base station. In the downlink, the transmitter is part of the base station and the receiver is part of the terminal.

Referring to FIG. 2, an OFDMA transmitter includes a serial to parallel converter 202, a sub-carrier mapping module 206, an M-point inverse discrete fourier transform (IDFT) module, and the like. 208, a cyclic prefix (CP) addition module 210, a parallel to serial converter (212) and a Radio Frequency (RF) / Digital to Analog Converter (DAC) module 214. .

Signal processing in the OFDMA transmitter is as follows. First, a bit stream is modulated into a data symbol sequence. The bit stream may be obtained by performing various signal processing such as channel encoding, interleaving, scrambling, etc. on the data block received from the medium access control (MAC) layer. The bit stream is also called a codeword (codeword) and is equivalent to a block of data received from the MAC layer. The data block received from the MAC layer is also called a transport block. The modulation scheme may include, but is not limited to, Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), and M-ary Quadrature Amplitude Modulation (m-QAM). Thereafter, the serial data symbol sequences are converted N by N in parallel (202). The N data symbols are mapped to the allocated N subcarriers among the total M subcarriers, and the remaining M-N carriers are padded with zeros (206). Data symbols mapped to the frequency domain are converted to time domain sequences through M-point IDFT processing (208). Thereafter, in order to reduce inter-symbol interference (ISI) and inter-carrier interference (ICI), an OFDMA symbol is generated by adding a CP to the time-domain sequence. The generated OFDMA symbols are converted 212 in parallel to serial. Thereafter, the OFDMA symbol is transmitted to the receiver through the process of digital-to-analog conversion, frequency upconversion, etc. (214). The other user is allocated an available subcarrier among the remaining M-N subcarriers. The OFDMA receiver includes an RF / ADC (Analog to Digital Converter) module 216, a serial / parallel converter 218, a Remove CP module 220, an M-point Discrete Fourier Transform (DFT) module 222, Subcarrier demapping / equalization module 224, bottle / serial converter 228, and detection module 230. The signal processing of the OFDMA receiver consists of the inverse of the OFDMA transmitter.

The SC-FDMA transmitter further includes an N-point DFT module 204 before the subcarrier mapping module 206 as compared to the OFDMA transmitter. SC-FDMA transmitter can significantly reduce the peak-to-average power ratio (PAPR) of the transmission signal compared to the OFDMA scheme by spreading a plurality of data in the frequency domain through the DFT prior to IDFT processing. The SC-FDMA receiver further includes an N-point IDFT module 226 after the subcarrier demapping module 224 as compared to the OFDMA receiver. The signal processing of the SC-FDMA receiver consists of the inverse of the SC-FDMA transmitter.

3 is a diagram illustrating a structure of a radio frame used in LTE.

Referring to FIG. 3, a 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 0.5ms (15360? Ts). Here, Ts represents a sampling time and is represented by Ts = 1 / (15 kHz x 2048) = 3.2552 x 10 -8 (about 33 ns). The slot includes a plurality of OFDMA (or SC-FDMA) symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain. In an LTE system, one resource block includes 7 or 6 OFDMA (or SC-FDMA) symbols over 12 subcarriers. Here, the number of OFDMA (or SC-FDMA) symbols in one resource block depends on the length of a CP (normal cyclic prefix or extended cyclic prefix) used. A transmission time interval (TTI), which is a unit time in which data is transmitted, 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 in the radio frame, the number of slots in the subframe, and the number of OFDMA (or SC-FDMA) symbols in the slot may be variously changed.

4 is a diagram illustrating an example of performing communication in a single configuration carrier situation. 4 may correspond to a communication example of an LTE system. In the frequency division duplex (FDD) scheme, data transmission and reception are performed through one downlink band and one uplink band corresponding thereto. Specifically, in the FDD scheme, the radio frame structure of FIG. 4 is used only for downlink transmission or uplink transmission. On the other hand, in the time division duplex (TDD) scheme, the same frequency band is divided into a downlink section and a corresponding uplink section in the time domain. Specifically, in the TDD scheme, the radio frame structure of FIG. 4 is divided for downlink transmission and uplink transmission corresponding thereto.

Referring to FIG. 4, a method of performing a hybrid automatic repeat and reQuest (HARQ) process by the terminal will be described. In the LTE system, control information (eg, scheduling information) for downlink data transmission of a base station is transmitted to a terminal through a downlink control channel set in a control region of a downlink subframe. The downlink control channel includes a physical downlink control channel (PDCCH). The terminal receives scheduling information (eg, data allocated to the data, data size, coding scheme, redundancy version, etc.) through the control channel, and then receives scheduled data through the downlink shared channel indicated by the scheduling information. can do. The downlink shared channel includes a Physical Downlink Channel (PDSCH). Thereafter, the terminal may transmit a reception response signal (eg, HARQ ACK / NACK, DTX) for the downlink data to the base station through an uplink control channel set in the control region of the uplink subframe. The uplink control channel includes a PUCCH (Physical Uplink Control Channel). For convenience, in the present specification, HARQ ACK / NACK is simply indicated as an ACK / NACK signal. After receiving an ACK / NACK signal from the terminal, the base station retransmits the downlink data indicated by NACK or DTX. When the base station transmits a plurality of downlink data to the terminal, the HARQ process may be performed for each transport block corresponding to each downlink data.

5 is a diagram illustrating a structure of an uplink subframe used in an LTE system.

Referring to FIG. 5, an uplink subframe includes a plurality (eg, two) slots. The slot may include different numbers of SC-FDMA symbols according to the CP length. For example, in case of a normal CP, a slot may include 7 SC-FDMA symbols. The uplink subframe is divided into a data region and a control region. The data area includes a PUSCH and is used to transmit a data signal such as voice. The control region includes a PUCCH and is used to transmit control information. The PUCCH includes RB pairs (eg, m = 0, 1, 2, 3) located at both ends of the data region on the frequency axis and hops to a slot boundary. The control information includes ACK / NACK, CQI, PMI, RI, and the like. In addition, in the LTE system, the PUSCH and the PUCCH are not simultaneously transmitted by one UE. Table 1 below shows the characteristics of the PUCCH format described in TS 36.211 Release-8, a 3GPP standard document.

Table 1

PUCCH format	Modulation scheme	Number of bits per subframe, M _bit
One	N / A	N / A
1a	BPSK	One
1b	QPSK		2
2	QPSK	20
2a	QPSK + BPSK	21
2b	QPSK + BPSK	22

6 is a diagram illustrating a PUCCH structure for transmitting ACK / NACK.

Referring to FIG. 6, in the case of a normal CP, three consecutive symbols located in the middle of a slot carry a reference signal UL RS, and control information (ie, ACK / NACK) is carried on the remaining four symbols. In the case of an extended CP, the slot includes six symbols and reference signals are carried on the third and fourth symbols. ACK / NACK from a plurality of terminals is multiplexed onto one PUCCH resource using a CDM scheme. The CDM scheme is implemented using a cyclic shift (CS) of a sequence for frequency spread and / or an orthogonal cover sequence for time spread. For example, ACK / NACK is a different Cyclic Shift (CS) (frequency spread) and / or a different Walsh / DFT orthogonal cover sequence (CG-CAZAC) sequence of Computer Generated Constant Amplitude Zero Auto Correlation. Time spreading). The w0, w1, w2, w3 multiplied after the IFFT is multiplied before the IFFT. In the LTE system, a PUCCH resource for transmitting ACK / NACK is represented by a combination of positions of frequency-time resources (eg, resource blocks), cyclic shift of a sequence for frequency spreading, and an orthogonal cover sequence for time spreading, and each PUCCH. Resources are indicated using PUCCH (Resource) Index.

FIG. 7 is a diagram illustrating an example of determining a PUCCH resource for ACK / NACK signal transmission. In the LTE system, the PUCCH resources for ACK / NACK are not pre-allocated to each UE, and a plurality of PUCCH resources are divided and used at every time point by a plurality of terminals in a cell. In more detail, the PUCCH resource used by the UE to transmit ACK / NACK corresponds to a PDCCH carrying scheduling information for a corresponding downlink data (PDSCH). The entire region in which the PDCCH is transmitted in each downlink subframe consists of a plurality of control channel elements (CCEs), and the PDCCH transmitted to the UE consists of one or more CCEs. The UE transmits ACK / NACK through a PUCCH resource corresponding to a specific CCE (eg, first or lowest CCE) among CCEs configuring the PDCCH received by the UE.

Referring to FIG. 7, each rectangle in a downlink component carrier (downlink component carrier) represents a CCE, and each rectangle in an uplink component carrier (UL CC) represents a PUCCH resource. Each PUCCH index corresponds to a PUCCH resource for ACK / NACK. If it is assumed that the information on the PDSCH is transmitted through the PDCCH configured to 4 ~ 6 CCE as shown in Figure 7, the UE ACK / NACK through the 4 PUCCH corresponding to the 4 CCE, the first CCE constituting the PDCCH Send it. FIG. 6 illustrates a case in which up to M PUCCHs exist in a UL CC when up to N CCEs exist in a downlink component carrier. N may be M, but it is also possible to design M and N values differently and to overlap the mapping of CCE and PUCCH.

Specifically, the PUCCH resource index in the LTE system is determined as follows.

Equation 1

Here, n ⁽¹⁾ _PUCCH represents a PUCCH resource index for transmitting ACK / NACK, N ⁽¹⁾ _PUCCH represents a signaling value received from the upper layer, n _CCE is the most of the CCE index used for PDCCH transmission Represents a small value.

8 is a diagram illustrating an example of performing communication under a multiple carrier configuration. 8 may correspond to an example of communication of the LTE-A system. The LTE-A system uses a carrier aggregation or bandwidth aggregation technique that collects a plurality of uplink / downlink frequency blocks and uses a larger uplink / downlink bandwidth to use a wider frequency band. Each frequency block is transmitted using a component carrier (CC).

Referring to FIG. 8, five 20 MHz component carriers may be gathered in the up / down link to support 100 MHz bandwidth. Component carriers may be contiguous or non-contiguous in the frequency domain. The radio frame structure illustrated in FIG. 3 may be equally applied even when using a multi-component carrier. However, since the radio frame, subframe, and slot are time units, for example, the base station and the terminal may transmit and receive signals through a plurality of component carriers on one subframe. FIG. 8 illustrates a case where both the bandwidth of the uplink component carrier and the bandwidth of the downlink component carrier are the same and symmetrical. However, the bandwidth of each component carrier can be determined independently. For example, the bandwidth of the uplink component carrier may be configured as 5 MHz (UL CC0) + 20 MHz (UL CC1) + 20 MHz (UL CC2) + 20 MHz (UL CC3) + 5 MHz (UL CC4). In addition, asymmetrical carrier aggregation is possible in which the number of UL CCs and the number of downlink component carriers are different. Asymmetric carrier aggregation may occur due to the limitation of available frequency bands or may be artificially established by network configuration. In addition, although the uplink signal and the downlink signal are illustrated as being transmitted through one-to-one mapped component carriers, the component carriers through which signals are actually transmitted may vary according to network settings or types of signals. For example, the component carrier on which the scheduling command is transmitted and the component carrier on which data is transmitted according to the scheduling command may be different. In addition, the up / downlink control information may be transmitted through a specific uplink / downlink component carrier regardless of mapping between component carriers.

Although not limited thereto, when the number of uplink component carriers is smaller than the number of downlink component carriers, the UE should transmit ACK / NACK for a plurality of downlink PDSCH transmissions through fewer uplink PUCCHs. In particular, ACK / NACK for a plurality of downlink PDSCH transmissions may be configured to be transmitted only through a specific uplink component carrier. Further, even when the number of uplink component carriers and downlink component carriers is the same, the terminal receives a plurality of transport blocks when using a multiple input multiple output (MIMO) transmission scheme or operating in TDD. In this case, the terminal should transmit the ACK / NACK signal for a plurality of transport blocks through a limited PUCCH resource. The ACK / NACK response transmitted through the uplink of the LTE system is an ACK / NACK response for a PDSCH with a corresponding PDCCH assigned with a PDCCH corresponding to a specific UE, and a DL SPS (Semi-persistent) indicated to the specific UE. ACK / NACK response to PDCCH indicating downlink SPS release (PDCCH) for release of scheduling), PDSCH allocated without a corresponding PDCCH to a specific UE (PDSCH without a corresponding PDCCH, meaning PDSCH allocated to SPS) There are three cases of an ACK / NACK response to. However, for the sake of convenience of description, it is collectively described as ACK / NACK for PDSCH transmission or ACK / NACK for data without such specific classification.

Hereinafter, a method for transmitting response information including an uplink control signal, that is, ACK / NACK, of a terminal proposed by the present invention will be described. In particular, in the method for transmitting a response signal according to the present invention, it is assumed that a plurality of PUCCH resources for transmitting an ACK / NACK signal are located in the same physical resource block, but the present invention is not limited thereto. Even if it is within a certain frequency range, PUCCH resources located in other physical resource blocks may be applicable as long as channel state similarities exist.

Meanwhile, in the present invention, the term 'component carrier' is used for convenience of description, but the component carrier used may be used as a cell. Here the cell is a combination of downlink resources and optionally uplink resources. In addition, the link between the carrier frequency of the downlink resource and the carrier resource of the uplink resource appears in the system information transmitted to the downlink resource.

In the description of the present invention, a description of a specific access method is described for convenience, but this is for convenience reasons, and for any access method (e.g., OFDMA, SC-FDMA, DFT-precoded OFDM (A), Clustered DFTs OFDM (A) Nx Transmission, etc.), and the present invention is not limited to a specific access method. The invention may be applied to a response to a download data (e.g. PDSCH) or a download control channel (e.g. PDCCH), and may be applied to an upload data (e.g. PUSCH) or an upload control channel (e.g. PUCCH). ) May be applied to the response. In addition, the channel through which the present invention is transmitted may also be download data (e.g., PDSCH) or download control channel (e.g., PDCCH), and upload data (e.g., PUSCH) or upload control channel (e.g., , PUCCH).

In the following description, it is assumed that simultaneous transmission of one or two codewords is assumed and ACK / NACK is transmitted for each codeword. However, the number of codewords that can be transmitted simultaneously and the unit of ACK / NACK transmission are not limited. That is, the unit in which ACK / NACK is transmitted may be each codeword, each component carrier file, or each subframe. Optionally, the unit in which the ACK / NACK is transmitted may be a result after performing various ACK / NACKs (bundling, omission, or the number of ACKs, etc.) on the spatial domain / frequency domain / time domain. .

It will be described assuming joint coding of ACK / NACK information for a plurality of configured configuration carriers. In addition, although a description has been made on the assumption of feedback on configured configuration carriers, this is for convenience of description and may also be applied to active configuration carriers or scheduling configuration carriers or feedback on detected configuration carriers. The reference object of the feedback is not limited to the application of the present invention.

Normal channel selection is to use a number of resources to convey specific information by selection of resources. Typical channel selection is a combination of resources (time / frequency resources or sequences (including cyclic shifts)) and constellations. Here, the channel carries specific information. For example, in the case of Rel-8 PUCCH Format 1 / 1a / 1b, a resource is selected as a combination of an orthogonal code, a cyclic shift, and a PRU (physical resource unit). Here, the plurality of resources for which channel selection is performed may be divided by the above three combinations.

9 is a diagram illustrating an example of a normal channel selection scheme.

A channel selection method such as the table of FIG. 9A may be used. In the following description, the values of the tables may refer to constellation values due to modulation (eg, BPSK or QPSK, etc.) in a specific channel. However, the values of the tables may be interpreted as a value multiplied by an assigned sequence, or a scrambled value or a covered value, not a constellation point. That is, the table values can be interpreted by any means that can be distinguished from each other. In the following description, the values in the table are described as modulated values for convenience of description.

Here, a and b may each be a specific non-zero number. For example, a may be used as '+1' and b may be used as '+1' or '-1'. In the example of FIG. 9A, when ACK is transmitted, resource 1 (= ch 1) is transmitted, and when NACK is transmitted, resource 2 (= ch 2) is transmitted. Here, reference signal (RS) in each resource is related to demodulation of data and does not have an independent meaning. Also, in all the descriptions that follow, '0' may mean that it is not actually used or transmitted.

Unlike FIG. 9 (a), FIG. 9 (b) shows a general channel selection method using constellation.

The example of FIG. 9 (a) shows a simple example without the use of complex constellations, but in the example of FIG. 9 (b), more information may be transmitted by further using constellations. 9B illustrates an example of using a constellation (for example, BPSK) capable of distinguishing two pieces of information.

In FIG. 9B, a, b, and c may each be a specific value other than a predetermined zero. However, it is preferable that b and c are located far from each other in the constellation. For example, a may be used as '+1', and b and c may be used as '+1' and '-1' or '-1' and '+1', respectively.

In the example of FIG. 9 (b), when the ACK / ACK is transmitted, it is modulated from resource 1 (= ch 1) to b. When the ACK / NACK is transmitted, it is modulated from resource 1 (= ch 1) to c. do. In case of transmitting the NACK / ACK, the resource 2 (= ch 2) is modulated to b and transmitted. Lastly, in case of transmitting NACK / NACK, it means that modulation is performed from resource 2 (= ch 2) to c.

As in FIG. 9 (a), in the general channel selection scheme, RS (reference signal) is used only for data demodulation and has no independent function in channel selection for ACK / NACK transmission. Therefore, as described above, the data area of each resource is used for distinguishing the ACK / NACK combination.

In the following, with respect to the present invention, enhanced channel selection will be described.

10 is a diagram illustrating an example of an extended channel selection method.

The extended channel selection method is a method in which a reference signal (RS) is used to transmit specific information in addition to general channel selection. That is, extended channel selection can convey specific information in three combinations of resources (physical time / frequency resources and / or sequences (including cyclic shift values)) and constellations up to RS. To ensure that That is, a scheme for transmitting more information or more robustly by using RS for channel selection is proposed.

In the case of the extended channel selection scheme, physical time / frequency resources need to be distinguished, unlike general channel selection. In the case of general channel selection from the example of FIG. 9, since the RS and the data always exist together, the positions of the plurality of resources (or channels) are not limited to each other. However, when the extended channel selection scheme is used, RS and data may not exist at the same time. In such a case, when using two different physical time / frequency resources (or PRUs), RS and data may be able to be transmitted in different physical time / frequency resources (or PRUs). In this case, channel demodulation through RS may be problematic. Therefore, in order to prevent this problem, in the extended channel selection scheme, RS and data should be transmitted through the same physical time / frequency resource (or the same PRU).

In order for RS and data to be transmitted through the same physical time / frequency resource, a plurality of channels must be configured to use the same physical time / frequency resource (or same PRU). It can be set to be divided into different sequences on the same physical time / frequency resource. That is, at the time of channel allocation, a plurality of channels may be set on the same physical time / frequency resource.

As another method of allowing RS and data to be transmitted through the same physical time / frequency resource, a method of setting a sequence combination to be used separately from each other may be used. That is, at the time of channel allocation, the RS and the sequence for the data are variously combined using a plurality of channels corresponding to different physical time / frequency resources, but the physical time / frequency resources for transmitting the actual sequence may be set to be the same. In this case, the physical time / frequency resource (or PRU) that transmits the actual sequence may be selected by a predetermined rule.

For example, the physical time / frequency resource of the channel where the RS is modulated to a non-zero value may be used for transmission, or the physical time / frequency resource of the channel where the data to be modulated to a non-zero value is located. You can also decide to use it for transmission.

Assuming the former case, FIG. 10 (a) illustrates that when transmitting NACK / NACK, the RS for CH1 is modulated by a and the data is modulated by a sequence for CH1 by a, so that the non-zero RS is located. In case of ACK / NACK transmission, the RS for CH2 is modulated with a and the data is modulated with a for CH1 sequence a, but the data is transmitted through the physical time / frequency resource of CH2 where the non-RS RS is located. Can be set to In case of NACK / ACK transmission, modulate RS for CH1 to a and data modulate CH2 sequence to a, but transmit it through the physical time / frequency resource of CH1 where non-RS RS is located.In case of transmitting ACK / ACK, RS for CH2 Can be modulated by a and the data is modulated by a modulating the sequence for CH2 by a to be transmitted over the physical time / frequency resources of CH2 where the RS is located. Herein, the modulation symbols of RS and data are assumed to be the same for convenience, but may be set differently for each CH or per transmission information.

Two optional limitations on the extended channel scheme described above are limitations in setting the physical time / frequency resource or sequence for RS and data. This restriction may be fixed in advance, or may be performed in consideration of one of the two in the assignment. If you consider one of them when assigning, you may need to indicate that.

With reference to FIG. 10, an RS also shows an example of extended channel selection for 2 A / N bits for using channel selection in connection with an extended channel selection scheme.

The values of the tables of FIGS. 10A to 10E may refer to constellation values by modulation (BPSK or QPSK, etc.) in a specific Ch-x. However, the value of the table may be interpreted as a multiplied value, a scrambled value, or a covering value, not a constellation, but a multiplied value. That is, the values in the table can be interpreted by any means that can be distinguished from each other. In the following description, the values are modulated for convenience.

In connection with FIG. 10 (a), the RS is used to distinguish whether the first A / N is ACK or NACK. Alternatively, the data is used to distinguish whether the second A / N is ACK or NACK. If the RS is modulated (or multiplied or scrambled or covered) with a using the sequence for CH1, the first A / N bit represents N and A if modulated with a using the sequence for CH2. Reference to ACK or NACK by 0 and a is not limited to the present invention.

Referring to Fig. 10 (b), an example of analysis different from Fig. 10 (a) is shown. Here, whether each RS and data represents the first A / N information or the second A / N information is not limited to the present invention. Here, a may be a specific number other than 0, respectively. For example, a may be used as '+1' or '-1'. In addition, for convenience, the same description as using 'a' in the RS and data, for example, it is also possible to use a different modulated value between the RS and the data. In FIG. 10 (b), the first A / N bit represents A when RS is modulated to a using the sequence for CH1 and N when modulated to a using the sequence for CH2.

10 (a) and 10 (b), the RS and data each indicate specific A / N bit information. However, RS and data may be configured to represent A / N bit information as a combination of RS and data, respectively, without indicating specific A / N bit information. These examples are shown in Figs. 10 (c) to 10 (e).

In the example of Fig. 10 (c), only one of a total of four values of RS and data over two channels is modulated according to A / N information. That is, one of four values represents a combination of A / N information.

In the example of FIG. 10 (d), a total of four combinations of RS and data over two channels allow the value to be used in a distant form. That is, one of four values represents a combination of A / N information. In other words, in the example of FIG. 10 (c), it depends on a specific single value. If the single value is incorrectly detected / demodulated, the information is misinterpreted, while the distance is as shown in FIG. 10 (c). In the farther away it is possible to reduce the error for that detection / demodulation. In the example of FIG. 10 (c) there is a minimum distance of 1, while in the example of FIG. 10 (d) a distance of at least 2 is guaranteed.

In the example of FIG. 10 (e), the distance was largely arranged similarly to the example of FIG. 10 (d). In the example of FIG. 10 (e), an example in which the distance per channel is made evenly is made by spreading the distance where the distance exists over a plurality of channels.

The extended channel scheme described with reference to FIG. 10 is exemplary, and various applications may exist according to various combinations of RS and data.

The above-described extended channel selection scheme can transmit more information, but can increase the complexity at the base station. In addition, more errors may appear because more information is transmitted in the same resource.

Therefore, by selecting such a channel selection method, a terminal that does not need a lot of information can be robust transmission using a general channel selection technique, and a method that can transmit such a lot of information to a terminal that requires more information It can be provided.

That is, the present invention proposes a complex use of the general channel selection scheme and the extended channel selection scheme described above.

We propose a scheme to decide whether to use the general channel selection method or the extended channel selection method based on a specific threshold or reference value. For example, when the number of bits to be transmitted is less than the predetermined threshold, the general channel selection method is used. When the number of bits to be transmitted is larger than the threshold, the extended channel selection method is used. For another example, the general channel selection method is used when the number of configured carriers is smaller than a predetermined threshold value, and the extended channel selection method is used when it is larger than the threshold value. For another example, if the total number of downlink subframes across the configured configuration carriers that need to respond in one ACK / NACK response unit (eg, one PUCCH) is less than a predetermined threshold, the general channel selection scheme may be used. If it is larger than the threshold, the extended channel selection method is used.

The present invention relates to specific criteria related to ACK / NACK information (e.g., number of bits to transmit, number of configured carriers, number of detected configuration carriers, number of received configuration carriers, number of active configuration carriers, set configuration carriers The total number of subframes across, the total number of subframes across the detected configuration carriers, the total number of subframes across the received configuration carriers, the total number of subframes across active configuration carriers, configured per component subcarrier A method of selecting a channel by comparing the maximum number of transport blocks or codewords of data or the number of transport blocks or codewords of received data with a predetermined threshold value ( General channel selection method or extended channel selection method). In addition, the present invention relates to an operating method for a plurality of resources according to this threshold.

11 is a flowchart illustrating a flow of a complex channel selection scheme in accordance with the present invention.

The terminal receives downlink data from the base station (S1110). In this case, the base station may receive downlink data through at least one component carrier. When the terminal receives the downlink data, there is a need to transmit response information for the component carrier. The terminal determines a channel determination criterion for transmitting the response information (for example, the number of component carriers, the number of downlink subframes that need to respond in one response information transmission (one PUCCH), and a transmission block of data configured per component subcarrier) The state is determined according to the maximum number of blocks or codewords, the number of transport blocks or codewords of the received data, the size of the data to be transmitted, and the like (S1120). For example, the state determination value is' the number of configuration subcarriers * the number of downlink subframes to respond in one response information transmission (one PUCCH) * the maximum number of transport blocks of the configured data per configuration subcarrier Can be set to '. Here, a predetermined rule (eg, spatial bundling, time-domain bundling, frequency-domain bundling, ACK-counter, etc.) may be used to determine the state. For example, spatial bundling may be applied between responses consisting of a plurality of transmission blocks or between responses to a received subframe. As a result of the determination of the UE, when the state determined is larger than the threshold value (S1130), the extended channel selection method is selected (S1140), and when the state is small, the general channel selection method is selected (S1145). The terminal transmits response information such as A / N to the base station according to the selected scheme (S1150). By comparing with the threshold, the general channel method and the extended channel method can be used in combination.

As described above, in the case of the extended channel selection scheme, there must be a restriction of the plurality of physical time / frequency resource allocation or a sequence allocation for RS and data. Therefore, the allocation of resources associated with the channel selection according to the determination criteria should be preceded. In general, a criterion for determining the number of configured carriers, the number of A / N bits, and the like is signaled by a base station. The signaling may be broadcast, may be unicast, may be a higher signal (eg, an RRC signal), or may be a physical signal.

Since the base station can control the channel selection criterion, the base station already knows which channel selection method the terminal uses. Therefore, the base station can know in advance the channel selection method to be selected by the terminal through a comparison of the threshold value. At this time, the base station should allocate resources appropriate to the channel selection method to be selected by the terminal through the test. That is, when the terminal selects the general channel selection method, a plurality of resources can be allocated without restriction. However, if the terminal selects the extended channel selection, resources must be allocated with special constraints.

When the extended channel selection scheme is used with the limitation of physical time / frequency resources, a plurality of physical time / frequency resources used for the extended channel selection should be allocated to have the same location. Alternatively, when only one physical time / frequency resource is allocated, it may be generated to assume that the same plurality of physical time / frequency resources are allocated. However, if the sequence (or code) and the physical time / frequency resources are allocated as a combination without distinction, the base station must allocate with constraints that the physical time / frequency resources are the same within the resource allocation.

When the extended channel selection scheme is used with constraints of RS and data sequences, the plurality of RS and data sequences used in the one extended channel selection scheme must be allocated to be different from each other. If the sequence (or code) and the physical time / frequency resources are allocated in combination without distinction, the base station must allocate the constraints such that RS and data sequences are different from each other within the resource allocation.

Unlike the above description, when allocating resources, it is also possible to allocate resources for the general channel selection scheme and the extended channel selection scheme differently.

In the description of the present invention, only the selection of two channel selection by one threshold has been described, but for convenience, it may be configured to be a selection by more thresholds and more channel selection methods and tables. have. In addition, the inclusion of additional threshold values other than the above method does not limit the present invention. For example, it may be configured to use a selection of channel selection like the above method using a specific threshold value, and to use different physical structures and A / N transmission methods through another second threshold value.

12 illustrates a base station and a terminal applicable to an embodiment of the present invention.

Referring to FIG. 12, a wireless communication system includes a base station (BS) 1210 and a terminal (UE) 1220. In the downlink, the transmitter is part of the base station 1210 and the receiver is part of the terminal 1220. In the uplink, the transmitter is part of terminal 1220 and the receiver is part of base station 1210. The base station 1210 and / or the terminal 1220 may have a single antenna or multiple antennas.

Terminal 1220 includes a processor 1222, a memory 1224, and an RF unit 1226. The processor 1222 may be configured to implement the procedures and / or methods proposed by the present invention. The memory 1224 is connected to the processor 1222 and stores various information related to the operation of the processor 1222. The RF unit 1226 is connected with the processor 1222 and transmits and / or receives a radio signal. That is, the RF unit 1226 includes a transmitting module and a receiving module.

Base station 1210 includes a processor 1212, a memory 1214, and a radio frequency (RF) unit 1216. The processor 1212 may be configured to implement the procedures and / or methods proposed by the present invention. The memory 1214 is connected with the processor 1212 and stores various information related to the operation of the processor 1212. The RF unit 1216 is connected to the processor 1212 and transmits and / or receives a radio signal. That is, the RF unit 1216 includes a transmitting module and a receiving module.

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature should be considered optional unless stated otherwise. Each component or feature may be embodied in a form that is not combined with other components or features. It is also possible to combine some of the components and / or features to form an embodiment of the invention. The order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is obvious that the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship in the claims or as new claims by post-application correction.

In this document, embodiments of the present invention have been mainly described based on data transmission / reception relations between a terminal and a base station. Certain operations described in this document as being performed by a base station may in some cases be performed by an upper node thereof. That is, it is obvious that various operations performed for communication with the terminal in a network including a plurality of network nodes including a base station may be performed by the base station or other network nodes other than the base station. A base station may be replaced by terms such as a fixed station, a Node B, an eNode B (eNB), an access point, and the like. In addition, the terminal may be replaced with terms such as a user equipment (UE), a mobile station (MS), a mobile subscriber station (MSS), and the like.

Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of a hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), FPGAs ( field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc. that performs the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit of the invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

The present invention can be applied to a wireless communication system. Specifically, the present invention can be applied to a method and apparatus for transmitting response information from a terminal to a base station in a wireless communication system to which carrier aggregation is applied.

Claims

A method of transmitting response information by a terminal in a wireless communication system supporting a plurality of downlink resources,

Receiving downlink data through each of the plurality of downlink resources from a base station;

Mapping response information on the plurality of downlink resources to a plurality of HARQ resources using any one of a first HARQ resource selection method and a second HARQ resource selection method; And

Transmitting the response information through the mapped plurality of HARQ resources;

Each of the plurality of HARQ resources includes a reference signal region and a data signal region,

The first HARQ resource selection method uses only a data signal region of each of the plurality of HARQ resources to identify the response information.

The second HARQ resource selection scheme uses a data signal region and a reference signal region of each of the plurality of HARQ resources to identify the response information.

How to send response information.
The method of claim 1,

In the step of mapping to the plurality of HARQ resources,

When the number of the plurality of downlink resources exceeds a first threshold, the response information is mapped to the plurality of HARQ resources by using the second HARQ resource selection method.

When the number of the plurality of downlink resources is less than or equal to a first threshold, the response information is mapped to the plurality of HARQ resources by using the first HARQ resource selection scheme.

How to send response information.
The method of claim 1,

In the step of mapping to the plurality of HARQ resources,

When the number of bits of the control signal to be transmitted through the response information exceeds a second threshold, the response information is mapped to the plurality of HARQ resources by using the second HARQ resource selection method,

When the number of bits of the control signal to be transmitted through the response information is less than or equal to a second threshold, the response information is mapped to the plurality of HARQ resources by using the first HARQ resource selection scheme.

How to send response information.
The method of claim 3, wherein

The number of bits of the control signal to be transmitted through the response information is the number of downlink resources configured, the number of subframes in each downlink resource to be responded through the one response information, and the maximum supportable transmission block configured for each downlink resource. calculated by one or more of the number of transport blocks,

How to send response information.
The method of claim 1,

The response information includes ACK / NACK information for the plurality of downlink resources.

How to send response information.
The method of claim 1,

When the response information is mapped in the second HARQ resource selection scheme, the plurality of HARQ resources to which the response information is mapped are transmitted through one physical time / frequency resource.

How to send response information.
A terminal in which a terminal transmits response information in a wireless communication system supporting a plurality of downlink resources,

A receiver for receiving downlink data through each of the plurality of downlink resources from a base station;

A processor configured to map response information on the plurality of downlink resources to a plurality of HARQ resources using any one of a first HARQ resource selection method and a second HARQ resource selection method; And

And a transmitter for transmitting the response information through the mapped plurality of HARQ resources.

Each of the plurality of HARQ resources includes a reference signal region and a data signal region,

The first HARQ resource selection method uses only a data signal region of each of the plurality of HARQ resources to identify the response information.

The second HARQ resource selection scheme uses a data signal region and a reference signal region of each of the plurality of HARQ resources to identify the response information.

Terminal.
The method of claim 7, wherein

The processor,

When the number of the plurality of downlink resources exceeds a first threshold, the response information is mapped to the plurality of HARQ resources by using the second HARQ resource selection method.

When the number of the plurality of downlink resources is less than or equal to a first threshold, the response information is mapped to the plurality of HARQ resources by using the first HARQ resource selection scheme.

Terminal.
The method of claim 7, wherein

The processor,

When the number of bits of the control signal to be transmitted through the response information exceeds a second threshold, the response information is mapped to the plurality of HARQ resources by using the second HARQ resource selection method,

When the number of bits of the control signal to be transmitted through the response information is less than or equal to a second threshold, the response information is mapped to the plurality of HARQ resources by using the first HARQ resource selection scheme.

Terminal.
The method of claim 9,

The number of bits of the control signal to be transmitted through the response information is the number of downlink resources configured, the number of subframes in each downlink resource to be responded through the one response information, and the maximum supportable transmission block configured for each downlink resource. calculated by one or more of the number of transport blocks,

Terminal.
The method of claim 7, wherein

The response information includes ACK / NACK information for the plurality of downlink resources.

Terminal.
The method of claim 7, wherein

When the response information is mapped in the second HARQ resource selection scheme, the plurality of HARQ resources to which the response information is mapped are transmitted through one physical time / frequency resource.

Terminal.