CN105846963B

CN105846963B - Method and apparatus for transmitting/receiving uplink control information in wireless communication system

Info

Publication number: CN105846963B
Application number: CN201610208267.9A
Authority: CN
Inventors: 李玹佑; 郑载薰; 韩承希
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2010-11-02
Filing date: 2011-11-02
Publication date: 2020-01-14
Anticipated expiration: 2031-11-02
Also published as: CN106130698B; CN106130698A; CN105846963A

Abstract

The present invention relates to a method and apparatus for transmitting/receiving uplink control information in a wireless communication system. According to one embodiment of the invention, the method for the terminal to transmit the acknowledgement response information in the wireless communication system comprises the following steps: a step of determining a PUCCH (physical uplink control channel) format and resources in which acknowledgement response information is transmitted in response to a downlink transmission in a downlink frame set including M (M ≧ 1) downlink subframes; and a step of transmitting the acknowledgement response information using the PUCCH format and resource in one uplink subframe. Here, more than one serving cell is set as the terminal, and the more than one serving cell may include one PCell and at least one SCell. When there is only one PDSCH from which a corresponding PDCCH is not detected on the PCell in the downlink subframe set and there is no SPS (semi-persistent scheduling) release PDCCH in the downlink subframe set, the acknowledgement response information can be transmitted using the PUCCH format 1a/1 b.

Description

Method and apparatus for transmitting/receiving uplink control information in wireless communication system

The present application is a divisional application of the patent application having an international application number 201180063439.3(PCT/KR2011/008292) filed on 28 th 6 th 2013 and 2011/11 th 2 th, entitled "method and apparatus for transmitting/receiving uplink control information in a wireless communication system".

Technical Field

The present invention relates to a radio communication system, and more particularly, to a method and apparatus for transmitting and receiving uplink control information.

Background

Wireless communication systems have been widely deployed to provide various types of communication services such as voice or data services. Generally, a wireless communication system is a multiple access system capable of supporting communication with multiple users by sharing available system resources (bandwidth, transmission power, etc.). Multiple-access systems include, for example, Code Division Multiple Access (CDMA) systems, Frequency Division Multiple Access (FDMA) systems, Time Division Multiple Access (TDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and multi-carrier frequency division multiple access (MC-FDMA) systems.

Disclosure of Invention

[ problem ] to provide a method for producing a semiconductor device

An object of the present invention is to provide a method for efficiently transmitting control information in a wireless communication system and an apparatus therefor. Another object of the present invention is to provide a channel format and signal processing method for efficiently transmitting control information and an apparatus therefor. It is still another object of the present invention to provide a method for efficiently allocating resources for control information transmission.

It will be apparent to those skilled in the art that the technical objects that can be achieved by the present invention are not limited to what has been particularly described above, and other technical objects of the present invention will become more clearly apparent from the following detailed description.

[ technical solution ] A method for producing a semiconductor device

The object of the present invention can be achieved by providing a method for transmitting acknowledgement/negative acknowledgement (ACK/NACK) information at a User Equipment (UE) in a wireless communication system, the method comprising: determining a Physical Uplink Control Channel (PUCCH) format and resources through which ACK/NACK information for downlink transmission in a downlink frame set including M (M ≧ 1) downlink subframes is to be transmitted; and transmitting ACK/NACK information using the PUCCH format and resources in one uplink subframe, wherein more than one serving cell including one primary cell (PCell) and at least one secondary cell (SCell) is configured for the UE, and the ACK/NACK information is transmitted using PUCCH format 1a/1b when one Physical Downlink Shared Channel (PDSCH) in which a corresponding Physical Downlink Control Channel (PDCCH) is not detected exists only on the PCell in a downlink subframe set and a semi-persistent scheduling (SPS) release PDCCH does not exist in a downlink subframe set.

In another aspect of the present invention, provided herein is a User Equipment (UE) for transmitting acknowledgement/negative acknowledgement (ACK/NACK) information in a wireless communication system, including: a reception module for receiving a downlink signal from a Base Station (BS); a transmitting module for transmitting an uplink signal to a BS; and a processor for controlling the UE comprising a receiving module and a transmitting module, wherein the processor is configured to: determining a Physical Uplink Control Channel (PUCCH) format and resources through which ACK/NACK information for downlink transmission in a downlink frame set including M (M ≧ 1) downlink subframes is transmitted, and transmitting ACK/NACK information using the PUCCH format and resources in one uplink subframe, and wherein, configuring more than one serving cell for the UE, and the more than one serving cells include one primary cell (PCell) and at least one secondary cell (SCell), and, when one Physical Downlink Shared Channel (PDSCH) in which a corresponding Physical Downlink Control Channel (PDCCH) is not detected exists only on the PCell in the downlink subframe set and a semi-persistent scheduling (SPS) release PDCCH does not exist in the downlink subframe set, the ACK/NACK information is transmitted using PUCCH format 1a/1 b.

The following may be commonly applied to the above embodiments of the present invention.

The resource index of the PUCCH format 1a/1b may be determined by a value of a Transmit Power Control (TPC) field of a PDCCH indicating SPS activation for one PDSCH in which a corresponding PDCCH is not detected.

When M is greater than 1, one PDSCH in which a corresponding PDCCH is not detected exists only on the PCell in the downlink subframe set, a PDSCH indicated by detection of the corresponding PDCCH in the downlink subframe set exists only on the PCell in the downlink subframe set, and a Downlink Assignment Index (DAI) value of the detected PDCCH is 1, ACK/NACK information may be transmitted by channel selection using PUCCH format 1b,

channel selection may be performed by selecting one PUCCH resource from a (where a is 2 or 3) PUCCH resources.

A may be determined based on the number of transport blocks transmitted in the downlink.

One of the a PUCCH resources may be determined by a value of a TPC field of a PDCCH indicating SPS activation for one PDSCH of the corresponding PDCCH is not detected therein, and the other of the a PUCCH resources may be derived from a Control Channel Element (CCE) index of the detected PDCCH.

The TPC field of the PDCCH having a DAI value of 1 on the PCell may indicate uplink TPC information, the TPC field of the PDCCH having a DAI value greater than 1 on the PCell may be used to determine a resource index of PUCCH format 3, and the TPC field of the PDCCH on each of the at least one SCell may be used to determine a resource index of PUCCH format 3.

The UE may assume that the same PUCCH resource index value is transmitted in all PDCCHs on the PCell and the at least one SCell used to determine the resource index of PUCCH format 3 in the downlink subframe set.

The wireless communication system may be a Time Division Duplex (TDD) wireless communication system.

The foregoing general description and the following detailed description of the invention are exemplary only, and are given as further description of the invention, which is defined by the appended claims.

[ PROBLEMS ] the present invention

According to the present invention, control information can be efficiently transmitted in a wireless communication system. Also, a channel format and a signal processing method for efficiently transmitting control information are provided. Also, resources for control information transmission can be efficiently allocated.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention. In the drawings:

fig. 1 is a block diagram illustrating constituent elements of a UE and a BS performing the present invention;

fig. 2 illustrates an exemplary structure of a transmitter in each of a UE and a BS;

fig. 3 illustrates an example of mapping input symbols to subcarriers in the frequency domain while satisfying a single carrier property;

fig. 4 to 6 illustrate examples of mapping input symbols to a single carrier by clustered DFT-s-OFDM;

figure 7 illustrates signal processing operations in segmented SC-FDMA;

fig. 8 illustrates an exemplary radio frame structure for use in a wireless communication system;

fig. 9 illustrates an exemplary DL/UL slot structure in a wireless communication system;

fig. 10 illustrates an exemplary DL subframe structure in a wireless communication system;

fig. 11 illustrates an exemplary UL subframe structure in a wireless communication system;

fig. 12 illustrates an example of determining PUCCH resources for ACK/NACK;

fig. 13 illustrates exemplary communication in a single carrier case;

fig. 14 illustrates exemplary communication in a multi-carrier case;

fig. 15 illustrates a concept that one MAC layer manages multiple carriers in a BS;

fig. 16 illustrates a concept in which one MAC layer manages multiple carriers in a UE;

fig. 17 illustrates a concept in which a plurality of MAC layers manage a plurality of carriers in a BS;

fig. 18 illustrates a concept in which a plurality of MAC layers manage a plurality of carriers in a UE;

fig. 19 illustrates another concept in which a plurality of MAC layers manage a plurality of carriers in a BS;

fig. 20 illustrates another concept in which a plurality of MAC layers manage a plurality of carriers in a UE;

fig. 21 and 22 illustrate slot level structures of PUCCH formats 1a and 1b for ACK/NACK transmission;

fig. 23 illustrates a case of transmitting UCI in a wireless communication system supporting CA;

fig. 24 to 27 illustrate a PUCCH format structure for feeding back a plurality of ACK/NACK bits and a signal processing operation thereof;

fig. 28 is a flowchart illustrating a predefined resource allocation for PUCCH resource determination in a PCell-only reception case;

fig. 29 is a flowchart illustrating an additional predefined resource allocation for PUCCH resource determination in a PCell-only reception case;

fig. 30 is a flowchart illustrating an example of using a DAI field as an ARI for PUCCH resource determination in a PCell-only reception case;

fig. 31 is a flowchart illustrating an example of using a TPC field as an ARI for PUCCH resource determination in a PCell-only reception case;

fig. 32 is a flowchart illustrating another example of using a TPC field as an ARI for PUCCH resource determination in a PCell-only reception case;

fig. 33 is a diagram illustrating an embodiment of using a TPC field for an original purpose or ARI purpose according to a DAI value on a PCell;

fig. 34 is a diagram illustrating an example of increasing DAI values in ascending order of CC indexes in a bundling window;

fig. 35 is a diagram illustrating an example of determining a DAI value in a CA TDD system;

fig. 36 to 39 illustrate various examples of using a DAI field in CC domain bundling;

FIG. 40 is a diagram illustrating an exemplary time-domain partial bundling;

fig. 41 is a diagram illustrating channel selection using PUCCH format 1b in CC domain bundling;

fig. 42 is a diagram illustrating channel selection using PUCCH format 3 in CC domain bundling;

fig. 43 is a diagram illustrating an example of use of DAI and TPC;

fig. 44 is a diagram illustrating another example of use of DAI and TPC;

fig. 45 is a diagram illustrating an example of the present invention for use of a TPC field in a PDCCH; and

fig. 46 is an overall flowchart illustrating an ACK/NACK transmission method for various DL transmissions according to an example of the present invention.

Detailed Description

The embodiments of the invention described below are combinations of elements and features of the invention in predetermined forms. Elements or features may be considered optional unless otherwise specified. Each element or feature may be implemented without being combined with other elements or features. Also, the embodiments of the present invention may be configured by combining parts of elements and/or features. The order of operations described in the embodiments of the present invention may be rearranged. Some configurations of any one embodiment may be included in another embodiment, and may be replaced with corresponding configurations of another embodiment.

In the embodiments of the present invention, a description is given of a data transmission and reception relationship between a Base Station (BS) and a terminal. Here, the BS refers to a terminal node of a network that directly communicates with a terminal. In some cases, certain operations described as being performed by the BS may be performed by an upper node of the BS.

In other words, it is apparent that, in a network configured by a plurality of network nodes including the BS, various operations performed for communication with the terminal may be performed by the BS or network nodes other than the BS. The term "BS" may be replaced by terms such as fixed station, node B, e node b (enb), Access Point (AP), etc. Also herein, the term BS may be used as a concept including a cell or a sector. Meanwhile, the "relay" may be replaced with terms such as a Relay Node (RN), a Relay Station (RS), and the like. The term "terminal" may be replaced with terms such as User Equipment (UE), Mobile Station (MS), mobile subscriber station (MSs), Subscriber Station (SS), and the like.

Specific terms disclosed in the present invention are proposed to aid in understanding the present invention, and the use of these specific terms may be changed to another format within the technical scope or spirit of the present invention.

In some cases, well-known structures and devices may be omitted so as not to obscure the concept of the present invention, and important functions of the structures and devices may be shown in block diagram form. The same reference numbers will be used throughout the drawings to refer to the same or like parts.

Embodiments of the present invention can be supported by standard documents disclosed in at least one of wireless access systems including an Institute of Electrical and Electronics Engineers (IEEE)802 system, a third generation partnership project (3GPP) system, a 3GPP Long Term Evolution (LTE) system, a 3GPP LTE-advanced (LTE-a) system, and a 3GPP2 system. Specifically, in the embodiments of the present invention, steps or portions which are not described to clearly disclose the technical idea of the present invention may be supported by the above documents. All terms used herein may be supported by the above-mentioned documents.

The following techniques can be used for various radio access systems such as Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and the like. CDMA may be embodied by a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA 2000. TDMA may be embodied by a radio technology such as global system for mobile communications (GSM)/General Packet Radio Service (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented by radio technologies such as Institute of Electrical and Electronics Engineers (IEEE)802.11(Wi-Fi), IEEE802.16(WiMAX), IEEE 802-20, and evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). The 3GPP LTE is part of an evolved UMTS (E-UMTS) that uses E-UTRA. The 3GPP LTE employs OFDMA in downlink and SC-FDMA in uplink. LTE-A is an evolved version of 3GPP LTE. WiMAX may be illustrated by IEEE802.16 e (Wireless MAN-OFDMA reference System) and advanced IEEE802.16 m (Wireless MAN-OFDMA advanced System). For clarity, the following description focuses on the 3GPP LTE and LTE-a systems. However, the technical features of the present invention are not limited thereto.

Fig. 1 is a block diagram illustrating constituent elements of a UE and a BS performing the present invention.

The UE operates as a transmitter on the uplink and as a receiver on the downlink. In contrast, a BS operates as a receiver on the uplink and as a transmitter on the downlink.

The UE and the BS include: antennas 500a and 500b for receiving information, data, signals and/or messages; transmitters 100a and 100b for transmitting a message by controlling an antenna; receivers 300a and 300b for receiving messages through the control antenna; and memories 200a and 200b for storing various types of information related to communication in the wireless communication system. The UE and the BS further include processors 400a and 400b operatively connected to the constituent elements of the transmitter, receiver and memory included in the UE or the BS, for performing the present invention by controlling the constituent elements. The transmitter 100a, the receiver 300a, the memory 200a, and the processor 400a of the UE may be configured as independent components by separate chips, or two or more thereof may be integrated into one chip. The transmitter 100b, the receiver 300b, the memory 200b, and the processor 400b of the BS may be configured as independent components by separate chips, or two or more thereof may be integrated into one chip. The transmitter and receiver may be integrated into a single transceiver in the UE or BS.

The antennas 500a and 500b transmit or receive signals generated from the transmitters 100a and 100b to the outside and provide the received signals to the receivers 300a and 300 b. The antennas 500a and 500b are also referred to as antenna ports. Each antenna port may correspond to one physical antenna or may be configured by a combination of more than one physical antenna element. The signal transmitted through each antenna port cannot be re-decomposed by the receiving device. Reference Signals (RSs) transmitted corresponding to the antenna ports define the antenna ports viewed from the UE and enable the UE to perform channel estimation for the antenna ports regardless of whether the channel is a single radio channel from one physical channel or a composite channel from a plurality of physical antenna elements including the antenna ports. That is, an antenna port is defined such that a channel over which a symbol is transmitted on the antenna port can be derived from a channel over which another symbol is transmitted on the same antenna port. If the transmitter and the receiver support Multiple Input Multiple Output (MIMO) in which a plurality of antennas are used to transmit and receive data, each of the transmitter and the receiver may be connected to two or more antennas.

In general, the processors 400a and 400b control the overall operation of the modules of the UE or the BS. In particular, the processors 400a and 400b may perform various control functions for implementing the present invention, a Medium Access Control (MAC) frame transition control function based on service characteristics and propagation environments, a power saving mode function for controlling idle mode operation, a handover function, an authentication and encryption function, and the like. The processors 400a and 400b may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. Meanwhile, the processors 400a and 400b may be configured as hardware, firmware, software, or a combination of hardware, firmware, and software. In a hardware configuration, the processors 400a and 400b may include Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), and the like, which are configured to implement the present invention. In a firmware or software configuration, firmware or software may be configured to include modules, procedures, functions, and the like, which perform the functions or operations of the present invention. Firmware or software configured to implement the present invention may be included in the processors 400a and 400b or may be stored in the memories 200a and 200b and executed by the processors 400a and 400 b.

The transmitters 100a and 100b encode and modulate signals and/or data scheduled by the processors 400a and 400b or by schedulers connected to the processors and transmitted to the outside, and transmit the modulated signals and/or data to the antennas 500a and 500 b. For example, the transmitters 100a and 100b convert data streams to be transmitted into K layers through demultiplexing, channel coding, and modulation. The K layers are transmitted by antennas 500a and 500b via the transmitter's transmit processor. The transmitters 100a and 100b and the receivers 300a and 300b of the UE and the BS may be differently configured according to an operation of processing a transmission signal and a reception signal.

The memories 200a and 200b may store programs for processing and control in the processors 400a and 400b, and may temporarily store input and output information. The memories 200a and 200b may serve as buffers. The memories 200a and 200b may be configured using a flash memory type, a hard disk type, a multimedia card micro type, a card type memory (e.g., a Secure Digital (SD) or ultra digital (XD) memory), a Random Access Memory (RAM), a Static Random Access Memory (SRAM), a Read Only Memory (ROM), an Electrically Erasable Programmable Read Only Memory (EEPROM), a Programmable Read Only Memory (PROM), a magnetic memory, a magnetic disk, an optical disk, and the like.

Fig. 2 illustrates an exemplary structure of a transmitter in each of the UE and the BS. The operation of transmitters 100a and 100b is described in more detail below with reference to fig. 2.

Referring to fig. 2, each of the transmitters 100a and 100b includes a scrambler 301, a modulation mapper 302, a layer mapper 303, a precoder 304, a Resource Element (RE) mapper 305, and an Orthogonal Frequency Division Multiplexing (OFDM) signal generator 306.

Transmitters 100a and 100b may transmit more than one codeword. The scrambler 301 scrambles the coded bits of each codeword for transmission on a physical channel. The codeword may be referred to as a data stream and is equivalent to a data block provided from the MAC layer. The data block provided from the MAC layer is referred to as a transport block.

The modulation mapper 302 modulates the scrambled bits into complex-valued modulation symbols. The modulation mapper 302 may modulate the scrambled bits into complex-valued modulation symbols representing positions on a signal constellation according to a predetermined modulation scheme. The modulation scheme is not limited, and m-phase shift keying (m-PSK) and m-quadrature amplitude modulation (m-QAM) may be used to modulate the encoded data.

The layer mapper 303 maps the complex-valued modulation symbols to one or more transmission layers.

The layer mapper 303 may precode the complex modulation symbols on each layer for transmission through the antenna ports. More specifically, the precoder 304 generates antenna-specific symbols by processing complex-valued modulation symbols for a plurality of transmit antennas in a MIMO scheme, and distributes the antenna-specific symbols to the RE mapper 305. That is, the precoder 304 maps the transmission layers to antenna ports. The precoder 304 may multiply the output x of the layer mapper 303 by N_t×M_tPrecoding a matrix W and N_t×M_FThe matrix z is formed to output the resulting product.

The RE mapper 305 maps/assigns the complex-valued modulation symbols for the corresponding antenna ports to REs. The RE mapper 305 may allocate complex-valued modulation symbols for respective antenna ports to appropriate subcarriers and may multiplex them according to the UE.

The OFDM signal generator 306 modulates the complex-valued modulation symbols, i.e., antenna-specific symbols, for the respective antenna ports through OFDM or single-carrier frequency division multiplexing (SC-FDM), thereby generating complex-valued time domain OFDM or SC-FDM symbol signals. OFDM signal generator 306 may perform an Inverse Fast Fourier Transform (IFFT) on the antenna-specific symbols and insert a Cyclic Prefix (CP) into the resulting IFFT time-domain symbols. The OFDM symbols are passed through the transmit antennas 500-1 to 500-N after digital-to-analog conversion, frequency up-conversion, and so on_tIs transmitted to the receiver. The OFDM signal generator 306 may include an IFFT module, a CP inserter, a digital-to-analog converter (DAC), a frequency up-converter, and the like.

Meanwhile, if the transmitters 100a and 100b employ SC-FDMA for transmission of codewords, the transmitters 100a and 100b may include a Discrete Fourier (DFT) module 307 (or a Fast Fourier Transform (FFT) module). The DFT module performs DFT or FFT on the antenna-specific symbols and outputs DFT/FFT symbols to the RE mapper 305. SC-FDMA is a transmission scheme for transmitting a signal by reducing a peak-to-average power ratio (PAPR) or Cubic Metric (CM) of the signal. According to SC-FDMA, a signal can be transmitted without passing through a nonlinear distortion region of a power amplifier. Therefore, even when the transmitter transmits a signal at a power lower than that in the conventional OFDM scheme, the receiver can receive a signal satisfying a constant strength or error rate. That is, the power consumption of the transmitter can be reduced by SC-FDMA.

In the conventional OFDM signal generator, signals carried on each carrier are simultaneously transmitted in parallel with each other by a multi-carrier modulation (MCM) while passing through an IFFT, thereby reducing the efficiency of the power amplifier. On the other hand, in SC-FDMA, information is DFT/FFT performed before the signal is mapped to subcarriers. The signal passing through the DFT module 307 has an increased PAPR by the DFT/FFT effect. The DFT/FFT-processed signal is mapped to subcarriers, IFFT-processed, and converted into a time-domain signal. That is, the SC-FDMA transmitter further performs a DFT or FFT operation before the OFDM signal generator so that the PAPR of the transmitted signal is increased at the IFFT input stage and is finally decreased while passing through the IFFT again. This scheme is called DFT-spread OFDM (DFT-s-OFDM) because it looks like adding a DFT module (or FFT module) 307 before the existing OFDM signal generator.

SC-FDMA should satisfy single carrier property. Fig. 3 illustrates an example of mapping input symbols to subcarriers in the frequency domain while satisfying a single carrier property. If DFT symbols are allocated to subcarriers according to one of the schemes shown in fig. 3(a) and 3(b), a transmission signal satisfying a single carrier property can be obtained. Fig. 3(a) illustrates centralized mapping, and fig. 3(b) illustrates distributed mapping.

Meanwhile, the transmitters 100a and 100b may employ clustered DFT spread OFDM (DFT-s-OFDM). Clustered DFT-s-OFDM is a modified version of conventional SC-FDMA. In the clustered DFT-s-OFDM, a signal passing through the DFT/FFT module 307 and the precoder 304 is divided into a predetermined number of sub-blocks and mapped to subcarriers in a discontinuous manner. Fig. 4 to 6 illustrate examples of mapping input symbols to a single carrier by clustered DFT-s-OFDM.

Fig. 4 illustrates signal processing operations for mapping DFT-processed output samples to single carriers in clustered SC-FDMA. Fig. 5 and 6 illustrate signal processing operations for mapping DFT-processed output samples to multiple carriers in clustered SC-FDMA. Figure 4 illustrates the application of intra-carrier clustered SC-FDMA, while figures 5 and 6 illustrate the application of inter-carrier clustered SC-FDMA. Fig. 5 illustrates signal generation by a single IFFT block in the following case: the subcarrier spacing between consecutive component subcarriers is aligned in the case where the component carriers are allocated consecutively in the frequency domain. Fig. 6 illustrates signal generation by a plurality of IFFT blocks in the case where component carriers are discontinuously allocated in the frequency domain.

Fig. 7 illustrates signal processing operations in segmented SC-FDMA.

Since the number of DFT blocks is equal to the number of IFFT blocks and thus the DFT blocks and IFFT blocks correspond one-to-one, segmented SC-FDMA is a simple extension of the DFT spreading and IFFT subcarrier mapping structure of conventional SC-FDMA and can be expressed as NxSC-FDMA or NxDFT-s-OFDMA. In the present disclosure, segmented SC-FDMA includes all of these items. Referring to fig. 7, in the segmented SC-FDMA, all modulation symbols in the time domain are divided into N groups (where N is an integer greater than 1), and a DFT process is performed in units of groups in order to release single carrier property constraints.

Referring back to fig. 2, the receivers 300a and 300b operate in reverse order of the operation of the transmitters 100a and 100 b. The receivers 300a and 300b decode and demodulate radio signals received from the outside through the antennas 500a and 500b, and transfer the demodulated signals to the processors 400a and 400 b. Antennas 500a and 500b connected to each of receivers 300a and 300b may include N_rA receiving antenna. The signal received through each receiving antenna is restored to a baseband signal and then to the original data streams transmitted by the transmitters 100a and 100b through multiplexing and MIMO demodulation. Each of the receivers 300a and 300b may include: a signal restorer for restoring the received signal to a baseband signal; a multiplexer for multiplexing the received and processed signals; and a channel demodulator for demodulating the multiplexed signal stream into a codeword. The signal recoverer, multiplexer and channel demodulator may be configured as an integrated module or as separate modules for performing their functions. More specifically, the signal recoverer may include: an analog-to-digital converter (ADC) for converting an analog signal to a digital signal; a CP remover for removing the CP from the digital signal; an FFT module for generating a frequency domain symbol by performing FFT on the CP-removed signal; and, an RE demapper/equalizer for recovering the antenna-specific symbols from the frequency domain symbol level. The multiplexer recovers the transmit layer from the antenna-specific symbols and the channel demodulator recovers the codewords transmitted by the transmitter from the transmit layer.

Meanwhile, if the receivers 300a and 300b receive the signal transmitted through SC-FDMA as described with reference to fig. 3 to 7, each of the receivers 300a and 300b further includes an IFFT module. The IDFT/IFFT module IDFT/IFFT processes the antenna-specific symbols recovered by the RE demapper and outputs IDT/IFFT symbols to the multiplexer.

Although it has been described in fig. 1 to 7 that each of the transmitters 100a and 100b includes the scrambler 301, the modulation mapper 302, the layer mapper 303, the precoder 304, the RE mapper 305, and the OFDM signal generator 306, it may be further considered to incorporate the scrambler 301, the modulation mapper 302, the layer mapper 303, the precoder 304, the RE mapper 305, and the OFDM signal generator 306 into each of the processors 400a and 400b of the transmitters 100a and 100 b. Also, although it has been described in fig. 1 to 7 that each of the receivers 300a and 300b includes the signal recoverer, the multiplexer, and the channel demodulator, it may be further considered to incorporate the signal recoverer, the multiplexer, and the channel demodulator into each of the processors 400a and 400b of the receivers 300a and 300 b. For convenience of explanation, the following explanation is given on the premise that: the scrambler 301, the modulation mapper 302, the layer mapper 303, the precoder 304, the RE mapper 305, and the OFDM signal generator 306 (further including the DFT module 307 in case of the SC-FDMA scheme) are included in the transmitters 100a and 100b configured to be separated from the processors 400a and 400b controlling the operations thereof, and the signal recoverer, the multiplexer, and the channel demodulator are included in the receivers 300a and 300b configured to be separated from the processors 400a and 400b controlling the operations thereof. However, even though the scrambler 301, the modulation mapper 302, the layer mapper 303, the precoder 304, the RE mapper 305, and the OFDM signal generator 306 (and 307) are included in the processors 400a and 400b, and the signal recoverer, the multiplexer, and the channel demodulator (further including the IFFT module in case of the SC-FDMA scheme) are included in the processors 400a and 400b, the embodiment of the present invention can be applied in the same manner.

Fig. 8 illustrates an exemplary radio frame structure used in a wireless communication system. Specifically, fig. 8(a) illustrates a radio frame of frame structure type 1(FS-1) in the 3GPP LTE/LTE-a system, and fig. 8(b) illustrates a radio frame of frame structure type 2(FS-2) in the 3GPP LTE/LTE-a system. The frame structure of fig. 8(a) may be applied to a Frequency Division Duplex (FDD) mode and a half FDD (H-FDD) mode, and the frame structure of fig. 8(b) may be applied to a Time Division Duplex (TDD) mode.

Referring to fig. 8, in 3GPP LTE/LTE-a, a radio frame has a length of 10ms (307200 Ts), including 10 equally sized subframes. The 10 subframes of a radio frame may be numbered. Here, T_sIs the sampling time, expressed as T _s1/(2048x 15 kHz). Each subframe is 1ms long and includes two slots. Can be numbered from 0 to 19 in sequence20 slots of a radio frame. Each slot has a length of 0.5 ms. The time required to transmit one subframe is defined as a Transmission Time Interval (TTI). The time resource may be identified by a radio frame number (or radio frame index), a subframe number (or subframe index), or a slot number (or slot index).

Different radio frames may be configured according to the duplex mode. For example, in the FDD mode, since downlink transmission and uplink transmission are distinguished by frequency, a radio frame includes a downlink subframe or an uplink subframe.

On the other hand, in the TDD mode, since downlink transmission and uplink transmission are distinguished by time, subframes in a frame are divided into downlink subframes and uplink subframes, and table 1 shows an exemplary uplink-downlink configuration in the TDD mode.

[ Table 1]

In table 1, D denotes a downlink subframe, U denotes an uplink subframe, and S denotes a special subframe. The special subframe includes three fields of a downlink pilot time slot (DwPTS), a Guard Period (GP), and an uplink pilot time slot (UpPTS). DwPTS is a time slot reserved for downlink transmission and UpPTS is a time slot reserved for uplink transmission.

Fig. 9 illustrates an exemplary downlink/uplink (DL/UL) slot structure in a wireless communication system. Specifically, fig. 9 illustrates a structure of a resource grid of a 3GPP LTE/LTE-a system. There is one resource grid per antenna port.

Referring to fig. 9, a slot includes a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols in a time domain and includes a plurality of Resource Blocks (RBs) in a frequency domain. An OFDM symbol may represent one symbol duration. The RB includes a plurality of subcarriers in the frequency domain. The OFDM symbols may be referred to as OFDM symbols, SC-FDM symbols, etc. according to a multiple access scheme. The number of OFDM symbols per slot may vary depending on the channel bandwidth and Cyclic Prefix (CP) length. For example, one slot includes 7 OFDM symbols in case of the normal CP, and one slot includes 6 OFDM symbols in case of the extended CP. Although a subframe is shown in fig. 8 as having a slot with 7 OFDM symbols for illustrative purposes, embodiments of the present invention are also applicable to subframes with any other number of OFDM symbols. A resource including one OFDM symbol multiplied by one subcarrier is called a Resource Element (RE) or tone (tone).

Referring to fig. 9, N may be included by^DL/UL _RBN^RB _scSub-carriers and N^DL/UL _symbThe resource grid of OFDM or SC-FDM symbols describes the signal transmitted in each slot. N is a radical of^DL _RBIndicates the number of RBs in the DL slot, and N^UL _RBIndicating the number of RBs in the UL slot. N is a radical of^DL _RBAnd N^UL _RBDepending on the DL transmission bandwidth and the UL transmission bandwidth, respectively. Each OFDM symbol includes N in the frequency domain^DL/UL _RBN^RB _scAnd (4) sub-carriers. The number of sub-carriers in one carrier is determined according to the FFT magnitude. The type of the subcarrier may be divided into a data subcarrier for data transmission, an RS subcarrier for RS transmission, and a null subcarrier for a guard band and a DC component. The null sub-carriers for the DC component remain unused and are mapped to the carrier frequency f during the generation of the OFDM signal₀. This carrier frequency is also referred to as the center frequency. N is a radical of^DL _symbIndicates the number of OFDM or SC-FDMA symbols in a DL slot, N^UL _symbDenotes the number of OFDM or SC-FDMA symbols in the UL slot, and N^RB _scIndicating the number of subcarriers constituting one RB.

In other words, a Physical Resource Block (PRB) is defined as N in the time domain^DL/UL _symbMultiplying a number of consecutive OFDM symbols or SC-FDMA symbols by N in the frequency domain^RB _scA number of consecutive subcarriers. Thus, one PRB includes N^DL/UL _symb×N^RB _scAnd (4) RE.

Each in the resource gridREs may be uniquely identified by an index pair (k, l) in a slot. k is in the range from 0 to N^DL/UL _RB×N^RB _sc-a frequency domain index of 1, and l is a number ranging from 0 to N^DL/UL _symb-a time domain index of 1.

Fig. 10 illustrates an exemplary DL subframe structure in a wireless communication system.

Referring to fig. 10, each subframe may be divided into a control region and a data region. The control region includes one or more OFDM symbols starting from the first OFDM symbol. The number of OFDM symbols used in the control region in a subframe may be independently configured in each subframe. Information on the number of OFDM symbols is transmitted through a Physical Control Format Indicator Channel (PCFICH). The BS may transmit various control information to one or more UEs through the control region. For control information transmission, a Physical Downlink Control Channel (PDCCH), a PCFICH, and a physical hybrid automatic repeat request indicator channel (PHICH) may be allocated to the control region.

The BS transmits information associated with resource allocation of a Paging Channel (PCH) and a downlink shared channel (DL-SCH) as transport channels, an UL scheduling grant, hybrid automatic repeat request (HARQ) information, a Downlink Assignment Index (DAI), etc., to each UE or UE group on the PDCCH.

The BS may transmit data for a UE or a UE group through the data region. The data transmitted through the data area is also referred to as user data. For transmission of user data, a Physical Downlink Shared Channel (PDSCH) may be allocated to the data region. The PCH and DL-SCH are transmitted through the PDSCH. The UE may read data transmitted through the PDSCH by decoding control information transmitted through the PDCCH. Information indicating to which UE or UE group PDSCH data is transmitted and information indicating how the UE or UE group should receive and decode PDSCH data are transmitted through the PDCCH. For example, it is assumed that a specific PDCCH is CRC-masked using a Radio Network Temporary Identity (RNTI) 'a' and information on data transmitted using a radio resource 'B' (e.g., frequency location) and using transport format information 'C' (e.g., transmission block size, modulation scheme, coding information, etc.) is transmitted through a specific subframe. Then, the UE in the cell monitors the PDCCH using its RNTI information. The UE having RNTI 'a' receives the PDCCH, and receives the PDSCH indicated by 'B' and 'C' through information of the received PDCCH.

Multiple PDCCHs may be transmitted in the control region. The UE may monitor multiple PDCCHs to detect its PDCCH. Downlink Control Information (DCI) carried by the PDCCH may differ in size and purpose according to a DCI format and in size according to a coding rate.

The DCI format may be independently applied for each UE, and PDCCHs of a plurality of UEs may be multiplexed in one subframe. The PDCCH of each UE may be independently channel-coded so that a Cyclic Redundancy Check (CRC) can be added to the PDCCH. The CRC is masked using a unique identifier of each UE so that each UE can receive its PDCCH. However, since the UE does not substantially know the location to which its PDCCH is transmitted, the UE is required to perform blind detection (also referred to as blind decoding) on all PDCCHs of the corresponding DCI format in each subframe until a PDCCH having its identifier is received.

Fig. 11 illustrates an exemplary UL subframe structure in a wireless communication system.

Referring to fig. 11, a UL subframe may be divided into a control region and a data region in a frequency domain. One or more Physical Uplink Control Channels (PUCCHs) may be allocated to the control region to carry Uplink Control Information (UCI). One or more Physical Uplink Shared Channels (PUSCHs) may be allocated to the data region to carry user data. If the UE employs the SC-FDMA scheme for uplink transmission, the PUCCH and the PUSCH cannot be simultaneously transmitted in order to maintain the single carrier property.

The UCI carried by the PUCCH may be different in size and purpose according to the PUCCH format and in size according to a coding rate. For example, the PUCCH format may be defined as follows.

[ Table 2]

In UL sub-frame, farA subcarrier of an ion Direct Current (DC) subcarrier is used as the control region. In other words, subcarriers located at both ends of the UL transmission bandwidth are assigned for UL control information transmission. The DC subcarrier is reserved not in signal transmission and is mapped to the carrier frequency f in the frequency up-conversion process caused by the OFDM/SC-FDMA signal generator 306₀。

A PUCCH for a UE is allocated to an RB pair in a subframe. The RBs of the RB pair occupy different subcarriers in two slots. This is called frequency hopping of RB pairs allocated to PUCCH beyond a slot boundary. However, if frequency hopping is not used, the RB pair occupies the same subcarriers. Regardless of frequency hopping, a PUCCH for one UE is assigned to one RB pair in one subframe, and thus, the same PUCCH is transmitted once by one RB in each slot, a total of two times, in one UL subframe.

Hereinafter, an RB pair for each PUCCH transmission of one subframe is referred to as a PUCCH region or PUCCH resource. In addition, for convenience of explanation, a PUCCH carrying acknowledgement/negative acknowledgement (ACK/NACK) is referred to as ACK/NACKPUCCH. A PUCCH carrying a Channel Quality Indicator (CQI)/Precoding Matrix Indicator (PMI)/Rank Information (RI) is referred to as a Channel State Information (CSI) PUCCH, and a PUCCH carrying a Scheduling Request (SR) is referred to as an SR PUCCH.

PUCCH resources for UCI transmission are assigned from the BS to the UE according to an explicit or implicit scheme.

UCI, such as ACK/NACK, CQI, PMI, RI, SR, etc., may be transmitted through a control region of the UL subframe.

In a wireless communication system, a BS and a UE transmit/receive signals or data to/from each other. If the BS/UE transmits data to the UE/BS, the UE/BS decodes the received data. If the data is successfully decoded, an ACK is transmitted to the BS/UE. If the data decoding fails, a NACK is transmitted to the BS/UE. In the 3GPP LTE system, the UE receives a data unit (e.g., PDSCH) from the BS and transmits ACK/NACK for the data unit to the BS through an implicit PUCCH resource determined by a PDCCH resource carrying scheduling information for the data unit.

Fig. 12 illustrates an example of determining PUCCH resources for ACK/NACK.

In the LTE system, PUCCH resources for ACK/NACK are not allocated to each UE in advance, and a plurality of UEs located in a cell use the plurality of PUCCH resources in a divided manner at each time point. Specifically, a PUCCH resource for ACK/NACK transmission of a UE is implicitly determined based on a PDCCH carrying scheduling information of a PDSCH carrying corresponding DL data. The entire region in which the PDCCH is transmitted in the DL subframe includes a plurality of Control Channel Elements (CCEs), and the PDCCH transmitted to the UE includes one or more CCEs. Each CCE includes a plurality of Resource Element Groups (REGs) (e.g., 9 REGs). When a Reference Signal (RS) is excluded, one REG is composed of four consecutive REs. The UE transmits ACK/NACK through an implicit PUCCH resource derived or calculated using a function of a specific CCE index (e.g., the first or lowest CCE index) among indexes of CCEs constituting a PDCCH received by the UE.

Referring to fig. 12, each PUCCH resource index corresponds to a PUCCH resource for ACK/NACK. As shown in fig. 12, assuming that PDSCH scheduling information is transmitted to the UE through a PDCCH consisting of CCEs numbered 4 to 6, the UE transmits ACK/NACK to the BS through a PUCCH derived or calculated from CCE number 4, i.e., the lowest CCE of the PDCCH, for example, through PUCCH number 4. Fig. 12 shows an example in which there are up to M' CCEs in a DL subframe and up to M PUCCH resources in a UL subframe. Although M 'may be equal to M, M' may be different from M and CCEs and PUCCH resources may be mapped in an overlapping manner.

For example, the PUCCH resource index may be determined as follows.

[ equation 1]

Here, n is⁽¹⁾ _PUCCHIs PUCCH resource index, N, for ACK/NACK transmission⁽¹⁾ _PUCCHIs a signaling value received from a higher layer, and n_CCERepresents the lowest CCE index used for PDCCH transmission.

Fig. 13 illustrates exemplary communication in a single carrier case. Fig. 13 may correspond to an example of communication in an LTE system.

Referring to fig. 13, a general FDD wireless communication system transmits and receives data through one DL band and one UL band corresponding to the DL band. The BS and the UE transmit and receive data and/or control information scheduled in units of subframes. Data is transmitted and received through a data region configured in the UL/DL subframe, and control information is transmitted and received through a control region configured in the UL/DL subframe. To this end, the UL/DL subframes carry signals on various physical channels. Although the description of fig. 13 is given based on the FDD scheme for convenience, the above description can also be applied to the TDD scheme by dividing the radio frame of fig. 8 into UL and DL frames in the time domain.

Fig. 14 illustrates exemplary communication in a multi-carrier case.

The LTE-a system uses carrier aggregation or bandwidth aggregation that uses a wider UL/DL bandwidth by aggregating a plurality of UL/DL frequency blocks in order to employ a wider frequency band. A multi-carrier system or a Carrier Aggregation (CA) system refers to a system that aggregates a plurality of carriers each having a narrower bandwidth than a target bandwidth for broadband support. When aggregating multiple carriers having a narrower bandwidth than the target bandwidth, the bandwidth of the aggregated carriers may be limited to the bandwidth used in the legacy system in order to maintain backward compatibility with the legacy system. For example, an LTE system may support bandwidths of 1.4, 3, 5, 10, 15, and 20MHz, and an LTE-advanced (LTE-a) system improved from the LTE system may support a bandwidth wider than 20MHz using the bandwidth supported in the LTE system. In addition, a new bandwidth may be defined to support CA regardless of the bandwidth used in the legacy system. The term multi-carrier can be used interchangeably with the terms CA and bandwidth aggregation. Continuous CA and discontinuous CA are collectively referred to as CA. For reference, when only one Component Carrier (CC) is used for communication in TDD, this corresponds to communication in the single carrier case (non-CA) of fig. 13. The UL CC and the DL CC are also referred to as UL resource and DL resource, respectively.

For example, referring to fig. 14, 5 CCs, each of which is 20MHz, may be aggregated on each of UL and DL to support a bandwidth of 100 MHz. The corresponding CCs may be continuous or discontinuous in the frequency domain. For convenience, fig. 14 shows a case in which the bandwidth of the ULCC is the same as the bandwidth of the DL CC and the two are symmetrical. However, the bandwidth of each CC may be determined independently. For example, the bandwidth of the UL CC may be configured in a manner of 5MHz (UL CC0) +20MHz (UL CC1) +20MHz (UL CC2) +20MHz (UL CC3) +5MHz (UL CC 4). Asymmetric CA can also be configured, where the number of UL CCs is different from the number of DL CCs. Asymmetric CAs may be generated due to limitations of available frequency bands or may be intentionally formed by network configuration. For example, even when the BS manages X DL CCs, a frequency band that can be received by a specific UE may be limited to Y (≦ X) DL CCs. In this case, the UE needs to monitor DL signals/data transmitted through Y CCs. In addition, even when the BS manages L UL CCs, the frequency band that can be received by a particular UE may be limited to M (≦ L) UL CCs. The restricted DL CC or UL CC for a specific UE is referred to as a serving UL or DL CC configured in the specific UE. The BS may allocate a prescribed number of CCs to the UE by activating some or all of the CCs managed by the BS or by disabling some of the CCs managed by the BS. The BS may change the activated/deactivated CCs and change the number of activated/deactivated CCs. Meanwhile, the BS can cell-specifically or UE-specifically configure Z DL CCs (where 1. ltoreq. Z. ltoreq. Y. ltoreq. X) that the UE should monitor/receive first as primary DL CCs. Also, the BS can configure, cell-specifically or UE-specifically, N UL CCs (where 1 ≦ N ≦ M ≦ L) that the UE should monitor/receive first as primary UL CCs. In this way, the restricted primary DL or UL CC for a specific UE is also referred to as a serving UL or DL CC configured in the specific UE. Various parameters for CA may be cell-specific, UE group-specific, or UE-specific configured.

Once a BS cell-specifically or UE-specifically allocates available CCs to a UE, at least one of the allocated CCs is not disabled unless overall CC allocation to the UE is reconfigured or the UE is handed over. Hereinafter, CCs that are not disabled unless overall CC allocation to the UE is reconfigured are referred to as primary CCs (pcc), and CCs that the BS can freely activate/disable are referred to as secondary CCs (scc). Single carrier communication uses one PCC for communication between a UE and a BS, and does not use an SCC for communication. Meanwhile, the PCC and SCC may also be distinguished based on control information. For example, specific control information may be set to be transmitted/received only through a specific CC. Such a specific CC may be referred to as a PCC, and the other CC or CCs may be referred to as one or more SCCs. For example, control information transmitted through the PUCCH may correspond to such specific control information. Accordingly, if control information transmitted on the PUCCH can be transmitted from the UE to the BS only through the PCC, the UL CC in which the PUCCH of the UE exists may be referred to as UL PCC, and the other one or more UL CCs may be referred to as one or more UL SCCs. As another example, if a UE-specific CC is used, the specific UE may receive a DL Synchronization Signal (SS) from the BS as specific control information. In this case, a DL CC (i.e., a DL CC for a network attempting to access a BS) used by the specific UE to establish synchronization of an initial DL time by receiving a DL SS may be referred to as a DL PCC, and the other DL CC(s) may be referred to as one or more DL SCCs. In a communication system according to LTE-a release 10, multicarrier communication uses one PCC and no SCC or one or more SCCs per UE. However, this is according to the definition of LTE-a, and it is possible to allow each UE to use communication of multiple PCCs in the future. The PCC may be referred to as a primary CC, an anchor CC, or a primary carrier, and the SCC may be referred to as a secondary CC or a secondary carrier.

LTE-a uses the concept of cells to manage radio resources. A cell is defined as a combination of DL resources and UL resources, i.e., a combination of DL CC and UL CC. Here, the UL resource is not an indispensable component. However, this is defined in the current LTE-a standard, and in the future, UL resources alone may be allowed to configure a cell. Therefore, the cell may be configured using DL resources alone or using both DL resources and UL resources. When CA is supported, an association between carrier frequencies of DL resources (or DL CCs) and carrier frequencies of UL resources (or UL CCs) may be indicated by system information. For example, the combination of DL resources and UL resources may be indicated by a system information block type 2(SIB 2). Here, the carrier frequency indicates a center frequency of each cell or CC. A cell operating on a primary frequency (or PCC) may be referred to as a primary cell (PCell), and one or more cells operating on a secondary frequency (or SCC) may be referred to as one or more secondary cells (one or more scells). The primary frequency (or PCC) refers to a frequency (or CC) for the UE to perform an initial connection setup or connection re-setup procedure. The PCell may refer to a cell indicated during a handover procedure. The secondary frequency (or SCC) refers to a frequency (or CC) that can be configured after RRC connection establishment is performed, and may be used to provide additional radio resources. The PCell and SCell may be collectively referred to as a serving cell. Therefore, for a UE in an RRC _ CONNECTED (RRC CONNECTED) state, for which CA is not configured or not supported, there is only one serving cell consisting of only PCell. Meanwhile, for a UE in an RRC _ CONNECTED state for which CA is configured, one or more serving cells may exist, and all the serving cells may include one PCell and one or more scells. However, in the future, the serving cell may be allowed to include a plurality of pcells. For CA, the network may configure one or more scells for CA-capable UEs in addition to the PCell initially configured in the connection establishment procedure after the initial security activation procedure is initiated. However, even if the UE supports CA, the network may configure only the PCell for the UE without adding the SCell. The PCell may be referred to as a primary CC, an anchor CC, or a primary carrier, and the SCell may be referred to as a secondary CC or a secondary carrier.

In a multi-carrier system, a BS may transmit multiple data units to a UE in a given cell or cells (or CC or CCs), and the UE may transmit ACK/NACK signals for the multiple data units in one subframe. The UE may be allocated one or more cells (or DL CCs) for receiving a PDSCH for DL data reception. A cell (or one or more DL CCs) for a UE may be semi-statically configured or reconfigured by RRC signaling. Also, a cell (or one or more DL CCs) for a UE may be dynamically activated/deactivated through L1/L2 (medium access control (MAC)) control signaling. Therefore, the maximum number of ACK/NACK bits to be transmitted by the UE varies according to a cell (or DL CC) available for the UE. That is, the maximum number of ACK/NACK bits to be transmitted through the UE is RRC configured/reconfigured or varies with the activated DL CC (or configured serving cell (s)) through L1/L2 signaling.

Fig. 15 depicts a concept that one MAC layer manages multiple carriers in a BS. Fig. 16 depicts the concept of one MAC layer managing multiple carriers in a UE.

Referring to fig. 15 and 16, one MAC layer manages one or more frequency carriers in order to perform transmission and reception. Since the frequency carriers managed by one MAC layer do not have to be contiguous, more flexible resource management is possible. In fig. 15 and 16, one physical layer (PHY) represents one CC for convenience. Here, one PHY does not necessarily represent a separate Radio Frequency (RF) device. Generally, one independent RF device represents one PHY but is not limited thereto. One RF device may include several PHYs.

Fig. 17 describes a concept that a plurality of MAC layers manage a plurality of carriers in a BS, and fig. 18 describes a concept that a plurality of MAC layers manage a plurality of carriers in a UE. Fig. 19 describes another concept in which a plurality of MAC layers manage a plurality of carriers in a BS, and fig. 20 describes another concept in which a plurality of MAC layers manage a plurality of carriers in a UE.

In addition to the structure as shown in fig. 15 and 16, a plurality of MAC layers instead of one MAC layer may control a plurality of CCs as shown in fig. 17 to 20.

As shown in fig. 17 and 18, each MAC layer may control each carrier in a one-to-one correspondence. As shown in fig. 19 and 20, each MAC layer may control each carrier in a one-to-one correspondence with respect to partial carriers, and one MAC layer may control one or more carriers with respect to other carriers.

The system applicable to the above description is a system supporting one carrier to N multiple carriers, and the carriers may be continuous or discontinuous carriers regardless of UL/DL. TDD systems are configured to manage N carriers, each carrier comprising DL and UL transmissions, and FDD systems are configured to use multiple carriers in UL and DL, respectively. FDD systems may support asymmetric CA, where the number of aggregated carriers and/or the bandwidth of the carriers in the UL and DL are different.

If the number of CCs aggregated in the UL is equal to the number of CCs aggregated in the DL, the CCs can be configured such that all CCs are compatible with CCs used in a legacy system. However, CCs that do not support compatibility are not excluded from the present invention.

For convenience of explanation, although explanation is given under the assumption that a PDSCH corresponding to a PDCCH is transmitted on a DL CC #0 when the PDCCH is transmitted on the DL CC #0, it is apparent that cross-carrier scheduling may be applied such that the PDSCH is transmitted on a DL CC different from the DL CC # 0.

Fig. 21 and 22 illustrate slot level structures of PUCCH formats 1a and 1b for ACK/NACK transmission.

Fig. 21 illustrates PUCCH formats 1a and 1b in the case of a normal CP, and fig. 22 illustrates PUCCH formats 1a and 1b in the case of an extended CP. The same control information is repeated on a slot basis in subframes of PUCCH formats 1a and 1 b. The UE transmits ACK/NACK signals through different Cyclic Shifts (CS) (frequency-domain codes) and different resources of an Orthogonal Cover (OC) or an orthogonal cover codec (OCCc) (time-domain spreading codec) of a computer-generated constant amplitude zero autocorrelation (CG-CAZACC) sequence. The OC includes, for example, walsh/DFT orthogonal codes. If the number of CSs is 6 and the number of OCs is 3, a total of 18 UEs may be multiplexed in the same Physical Resource Block (PRB) based on a single antenna. The orthogonal sequences w0, w1, w2 and w3 are applied in either the arbitrary time domain (after FFT modulation) or in the arbitrary frequency domain (before FFT modulation). PUCCH format 1 for SR transmission is the same as PUCCH formats 1a and 1b in the slot level structure and is different in modulation scheme.

The UE may be allocated PUCCH resources consisting of CS, OC and PRB through Radio Resource Control (RRC) signaling for SR transmission and for ACK/NACK feedback for semi-persistent scheduling (SPS). As described with reference to fig. 12, for dynamic ACK/NACK (or for non-persistently scheduled ACK/NACK) feedback or for ACK/NACK feedback of a PDCCH indicating SPS release, a PUCCH resource may be implicitly allocated to a UE using the lowest CCE index of a PDCCH corresponding to a PDSCH or PDCCH for SPS release.

Fig. 23 illustrates a scenario in which UCI is transmitted in a wireless communication system supporting CA. For convenience of explanation, it is assumed in this example that the UCI is ACK/NACK (A/N). However, the UCI may include control information such as CSI (e.g., CQI, PMI, and RI) and scheduling request information (e.g., SR), without limitation.

Fig. 23 illustrates an exemplary asymmetric CA, in which 5 DL CCs are linked to a single UL CC. The asymmetric CA may be set from the viewpoint of transmitting UCI. That is, the DL CC-UL CC association for UCI may be set differently from the DL CC-UL CC association for data. For convenience, if it is assumed that each DL CC can carry up to two codewords and the number of ACK/NACK bits for each CC depends on the maximum number of codewords set by each CC (for example, if the BS sets up to two codewords for a particular CC, even if a particular PDCCH uses only one codeword on the CC, the ACK/NACK bits for the CC are set to 2, i.e., the maximum number of codewords on the CC), at least two UL ACK/NACK bits are required for each DL CC. In this case, at least 10 ACK/NACK bits are required to transmit ACK/NACK for data received on 5 DL CCs on a single UL CC. If a Discontinuous Transmission (DTX) state is also indicated for each DL CC, at least 12 bits (═ 5) are required⁶3125-11.61 bits) for ACK/NACK transmission. This structure cannot transmit increased ACK/NACK information because up to two ACK/NACK bits are available in the conventional PUCCH formats 1a and 1 b. Although CA is given as an example of a cause of increasing the number of UCI, this case may also occur due to an increase in the number of antennas and the presence of backhaul subframes in the TDD system and the relay system. Similar to the ACK/NACK transmission, when control information related to a plurality of DL CCs is transmitted on a single UL CC, the amount of control information to be transmitted also increases. For example, transmission of CQI/PMI/RI information related to multiple DL CCs may increase UCI payload.

In fig. 23, a UL anchor CC (also referred to as UL PCC or UL primary CC) is a CC on which a PUCCH or UCI is transmitted, and may be cell/UE-specifically determined. In addition, the DTX status may be explicitly fed back, or may be fed back so as to share the same status as NACK.

Hereinafter, a method for effectively transmitting increased UCI will be proposed with reference to the accompanying drawings. In particular, a new PUCCH format/signal processing operation/resource allocation method for transmitting increased UCI is proposed. The new PUCCH format proposed by the present invention is referred to as CA PUCCH format or PUCCH format 3 relative to PUCCH format 2 defined in legacy LTE release 8/9. The technical features of the proposed PUCCH format may be easily applied to any physical channel (e.g., PUSCH) capable of communicating UCI in the same manner or in a similar manner. For example, the embodiments of the present invention are applicable to a periodic PUSCH structure in which control information is periodically transmitted or an aperiodic PUSCH structure in which control information is non-periodically transmitted.

The drawings and embodiments of the invention will be described focusing on the following cases: the UCI/RS symbol structure of the legacy LTE PUCCH format 1/1a/1b (normal CP) is used as the subframe/slot level UCI/RS symbol structure applied to PUCCH format 3. However, for convenience, a subframe/slot level UCI/RS symbol structure of PUCCH format 3 is exemplarily defined, and the present invention is not limited to such a specific structure. The number and position of UCI/RS symbols can be freely changed in the PUCCH format 3 of the present invention according to system design. For example, PUCCH format 3 according to one embodiment of the present invention may be defined using an RS symbol structure of PUCCH format 2/2a/2b of conventional LTE.

PUCCH format 3 according to an embodiment of the present invention may be used to transmit UCI of any type or size. For example, information such as HARQ ACK/NACK, CQI, PMI, RI, and SR may be transmitted in PUCCH format 3 according to an embodiment of the present invention. The information may have a payload of any size. For convenience of explanation, the following description focuses on the transmission of ACK/NACK information in PUCCH format 3 according to the present invention.

Fig. 24 to 27 illustrate a PUCCH format structure for feeding back a plurality of ACK/NACK bits and a signal processing operation thereof. For example, when a plurality of ACK/NACK bits are fed back in a multi-carrier environment, a PUCCH format may be used. Such PUCCH format may be referred to as PUCCH format 3 to distinguish it from the conventional series of PUCCH formats 1 and 2.

Fig. 24 to 27 illustrate DFT-based PUCCH format structures. According to the DFT-based PUCCH structure, the PUCCH is DFT-precoded and to which time domain OC is applied at the SC-FDMA level before transmission. Hereinafter, the DFT-based PUCCH format will be referred to as PUCCH format 3.

Fig. 24 illustrates an exemplary structure of a PUCCH format 3 of an OC using a Spreading Factor (SF)4 (SF-4). Referring to fig. 24, a channel coding block channel-codes information bits a _0, a _1,. -, a _ M-1 (e.g., a plurality of ACK/NACK bits) and generates coded bits (or codewords) b _0, b _1,. -, b _ N-1. M is the size of the information bits and N is the size of the code bits. The information bits include UCI, e.g., a plurality of ACK/NACKs for a plurality of data (or PDSCH) received on a plurality of DL CCs. Here, the information bits a _0, a _1,. -, a _ M-1 are jointly encoded regardless of the type/number/size of UCI constituting the information bits. For example, if the information bits include a plurality of ACK/NACKs for a plurality of DL CCs, channel coding is performed for the entire bit information, rather than for each DL CC or each individual ACK/NACK bit. A single codeword is generated by channel coding. Channel coding includes, but is not limited to, repetition, simplex coding, reed-muller (RM) coding, punctured RM coding, tail-biting convolutional coding (TBCC), low-density parity-check (LDPC) coding, or turbo coding. Although not shown, the coded bits may be rate-matched in consideration of a modulation order and an amount of resources. The rate matching function may be partially incorporated into the channel coding block or implemented in a separate functional block. For example, the channel coding block may obtain a single codeword by performing (32,0) RM coding with respect to a plurality of control information, and may perform circular buffer rate matching.

The modulator generates modulation symbols c _0, c _1, ·, c _ L-1 by modulating the coded bits b _0, b _1, ·, b _ M-1. L is the size of the modulation symbol. The modulation scheme is performed by varying the amplitude and phase of the transmitted signal. Modulation schemes include, for example, n-phase shift keying (n-PSK) and n-Quadrature Amplitude Modulation (QAM) (where n is an integer of 2 or more). In particular, the modulation scheme includes Binary PSK (BPSK), Quadrature PSK (QPSK), 8-PSK, QAM, 16-QAM, or 64-QAM.

The divider divides the modulation symbols c _0, c _1,. and c _ L-1 into slots. The order/mode/scheme of dividing the modulation symbols into slots is not limited to a specific one. For example, the divider may sequentially divide the modulation symbols into slots starting from the first modulation symbol (partial scheme). In this case, modulation symbols c _0, c _1, ·, c _ L-1 may be allocated to slot 0, and modulation symbols c _ L/2, c _ L/2+1,. ·, c _ L-1 may be allocated to slot 1. When the modulation symbols are divided into slots, the modulation symbols may be interleaved (arranged). For example, even-numbered modulation symbols may be allocated to slot 0, and odd-numbered modulation symbols may be allocated to slot 1. The modulation processing and the division processing may be interchanged in order.

The DFT precoder performs DFT precoding (e.g., 12-point DFT) with respect to modulation symbols divided into slots in order to generate a multicarrier waveform. Referring to fig. 24, modulation symbols c _0, c _1,. and c _ L/2-1 allocated to a slot 0 are DFT-precoded as DFT symbols d _0, d _1,. and d _ L/2-1, and modulation symbols c _ L/2, c _ L/2+1,. and c _ L-1 allocated to a slot 1 are DFT-precoded as DFT symbols d _ L/2, d _ L/2+1,. and d _ L/1. DFT precoding may be replaced with another linear operation (e.g., walsh precoding).

The spreading block spreads the DFT-precoded signal (in the time domain) at the SC-FDMA symbol level. The time domain spreading at the SC-FDMA symbol level is performed using a spreading code (sequence). The spreading codes include quasi-orthogonal codes and orthogonal codes. Quasi-orthogonal codes include, but are not limited to, pseudo-noise (PN) codes. Orthogonal codes include, but are not limited to, walsh codes and DFT codes. Although the orthogonal codes are described as typical examples of spreading codes for convenience of explanation, the orthogonal codes may be replaced with quasi-orthogonal codes. The maximum value of the spreading code size or SF is limited by the number of SC-FDMA symbols used for transmission of control information. For example, if four SC-FDMA symbols are used for control information transmission in one slot, length-4 orthogonal codes w0, w1, w2, w3 may be used in each slot. The SF indicates a spreading degree of the control information and may be related to a multiplexing order or an antenna multiplexing order of the UE. SF may vary to 1, 2, 3, 4 depending on system requirements. The SF may be predefined between the BS and the UE, or the BS may indicate the SF to the UE through DCI or RRC signaling. For example, if one of SC-FDMA symbols for control information is punctured to transmit an SRS, a spreading code having a reduced SF (e.g., SF-3 instead of SF-4) may be applied to the control information in a corresponding slot.

The signal resulting from the above operation is mapped to subcarriers in a PRB and converted into a time-domain signal through IFFT. A CP is added to the time domain signal and the generated SC-FDMA symbol is transmitted through the RF terminal.

Each operation will be described in more detail under the assumption that ACK/NACK is transmitted for 5 DL CCs. If each DL CC can transmit two PDSCHs, the ACK/NACK bit for the PDSCH may be 12 bits, including the DTX status. Under the assumption of QPSK and time spreading with SF-4, the size of the coded block (after rate matching) may be 48 bits. The coded bits are modulated into 24 QPSK symbols, and the QPSK symbols are divided into two slots, each slot comprising 12 QPSK symbols. The 12 QPSK symbols in each slot are converted into 12 DFT symbols through 12-point DFT. The 12 QPSK symbols in each slot are spread into four SC-FDMA symbols in the time domain using a spreading code of SF-4 and then mapped. Since 12 bits are transmitted on [2 bits x 12 subcarriers x 8 SC-FDMA symbols ], the coding rate is 0.0625 (12/192). If SF-4, a maximum of four UEs may be multiplexed per PRB.

Fig. 25 illustrates an exemplary structure of PUCCH format 3 using OC of SF-5.

The basic signal processing operation is performed in the same manner as described with reference to fig. 25 except for the number and positions of UCI SC-FDMA symbols and RS SC-FDMA symbols. The spreading block may be applied in advance at the front end of the DFT precoder.

In fig. 25, the RS may use the same structure as those used in the LTE system. For example, the base sequence may be cyclically shifted. The multiplexing capacity of the data portion is 5 since SF is 5. However, by CS interval Δ_shift ^PUCCHThe multiplexing capacity of the RS part is determined. For example, the multiplexing capacity may be 12/Δ_shift ^PUCCH. In this case, for a_shift ^PUCCH＝1、Δ _shift ^PUCCH2 and Δ_shift ^PUCCHThe multiplexing capacities for the case of 3 are 12, 6 and 4, respectively. In FIG. 25, although the data portion isThe multiplexing capacity is 5 because SF is 5, but the multiplexing capacity of the RS part is Δ_shift ^PUCCHIs 4 in the case of (1). Thus, the overall multiplexing capacity may be limited to the smaller of these two values 4.

Fig. 26 illustrates an exemplary structure of PUCCH format 3 capable of increasing multiplexing capacity at a slot level.

The overall multiplexing capacity can be increased by applying the SC-FDMA symbol-level spreading described with reference to fig. 24 and 25 to the RSs. Referring to fig. 26, the multiplexing capacity is doubled by applying walsh covering (or DFT code covering) within a slot. Then, the multiplexing capacity is even at Δ_shift ^PUCCHIs also 8 in the case of (1), thereby preventing the multiplexing capacity of the data portion from being reduced. In FIG. 26, [ y1 y 2]]＝[1 1]、[y1 y2]＝[1 -1]Or a linear transformation thereof (e.g., [ j j ]][j –j]、[1 j][1 –j]Etc.) can be used for the OC for the RS.

Fig. 27 illustrates an exemplary PUCCH format 3 structure capable of increasing multiplexing capacity at a subframe level.

Without applying slot-level frequency hopping, the multiplexing capacity is doubled again by applying walsh cover in units of slots. As described above, [ x1 x2] ═ 11, [ 1-1 ] or a conversion thereof can be used as the OC.

For reference, the processing operation of the PUCCH format 3 is not limited to the order shown in fig. 24 to 27.

Channel selection

Channel selection refers to the expression/transmission of specific information by selecting a specific resource from a plurality of resources. A common channel selection is a scheme for transmitting specific information through a combination of resources and constellations.

Here, the resources may be specified by physical time-frequency resources and/or sequence resources (e.g., CS values). For example, in LTE release 8 PUCCH format 1/1a/1b, a particular resource may be selected by a combination of OC, CS, and Physical Resource Unit (PRU). It can be assumed that a plurality of resources on which channel selection is performed are distinguished by a combination of the above three resources. For example, the channel selection method shown in table 3 below may be used.

[ Table 3]

In table 3 above and in the following description, the values expressed as a, b, c, … may represent constellation values resulting from modulation (e.g., BPSK, QPSK, etc.) in a channel Ch-x (x ═ 1, 2, 3,..). Alternatively, the values expressed as a, b, c, … may be values multiplexed, scrambled or covered by the assigned sequence or assigned code, rather than constellation values. Accordingly, the values expressed as a, b, c, … with respect to Ch-x may be values that can be distinguished therebetween, and the method for distinguishing between these values is not limited. In particular, in the following description, for convenience of description, a value expressed as a, b, c, … with respect to Ch-x is referred to as a modulation value.

In addition, the values expressed as a, b, c, … may be predetermined specific values instead of 0. For example, a can be '+ 1' and b can be '-1'.

In the example of table 3, even if the same value is transmitted, different information (i.e., ACK or NACK) may be transmitted depending on which channel is used for transmission. For example, for an ACK transmission, the value a is transmitted in the RS portion of resource 1 (i.e., channel 1) and the value b is transmitted in the data portion of resource 1. For NACK transmission, a is transmitted in the RS portion of resource 2 (i.e., channel 2) and b is transmitted in the data portion of resource 2. In this way, a method for transmitting different information depending on through which resource a signal is transmitted may be referred to as channel selection.

In table 3, a simple example is shown where no complex constellation mapping is used, but additional constellation mappings may be used for transmitting more information. Table 4 shows an example of using two types of distinguishable constellation mapping (e.g., BPSK).

[ Table 4]

In table 4 above, a, b, and c may be specific values other than 0. Note that it is preferable that b and c are distant 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', respectively, or '-1' and '+ 1', respectively. In the example of table 4, a value modulated as b is transmitted in resource 1 (channel 1) for ACK/ACK transmission and a value modulated as c is transmitted in resource 1 (channel 1) for ACK/NACK transmission. In addition, a value modulated to b is transmitted in resource 2 (channel 2) for NACK/ACK transmission, and a value modulated to c is transmitted in resource 2 (channel 2) for NACK/NACK transmission.

The mapping relationship of channel selection for ACK/NACK transmission in TDD, which is used in the conventional LTE release 8/9, is defined in tables 5, 6, and 7 shown below. In LTE release 8/9, TDD ACK/NACK multiplexing may have the same meaning as TDDACK/NACK channel selection, but they have different meanings in a multi-carrier support system (e.g., LTE-a or LTE release 10) described below.

In tables 5, 6 and 7 below, in the TDD system, K may be indexed by DL correlation set: { k } is a function of₀,k₁,…k_M-1As defined in table 12 described later). For example, if M is 2 in table 5, two PUCCH resources

And

and QPSK constellation 'b (0), b (1)' in each PUCCH resource may be used to transmit two types of ACK/NACK information, including spatial bundling (i.e., ACK/NACK bundling for multiple codewords).

Specifically, the UE uses PUCCH format 1b in ACK/NACK resources in subframe nThe upper transmit bit 'b (0), b (1)'. The values 'b (0), b (1)' and ACK/NACK resources may be generated by channel selection according to tables 5, 6 and 7 below

Tables 5, 6 and 7 show ACK/NACK multiplexing transmission when M-2, M-3 and M-4, respectively. If 'b (0), b (1)' is mapped to NACK/ACK, the UE does not transmit an ACK/NACK response in subframe n.

[ Table 5]

[ Table 6]

[ Table 7]

In tables 5, 6 and 7, HARQ-ACK (i) indicates HARQ ACK/NACK/DTX results for the ith (0 ≦ i ≦ 3) data unit. DTX means that no data units are transmitted for the corresponding HARQ-ack (i) or that the UE has not detected data units corresponding to HARQ-ack (i). In this specification, HARQ-ACK is used interchangeably with ACK/NACK. A maximum of four PUCCH resources (i.e., n) may be occupied for each data unit⁽¹⁾ _PUCCH,0To n⁽¹⁾ _PUCCH,3). The multiplexed ACK/NACK signal is transmitted through one PUCCH resource selected from the occupied PUCCH resources. In tables 5, 6 and 7, n⁽¹⁾ _PUCCH,xPUCCH resources for actual ACK/NACK transmission are indicated, and 'b (0) b (1)' indicates two bits transmitted through the selected PUCCH resource, which are modulated using QPSK. For example, if the UE successfully decodes four data units as in table 7, the UE connects to n⁽¹⁾ _PUCCH,1To transmit (1,1) to the BS. Since the combination of PUCCH resources and QPSK symbols cannot represent all available ACK/NACK, NACK and DTX are coupled (expressed as NACK/DTX) except in some cases.

Meanwhile, in the LTE-a (or LTE release 10) system to which the present invention is applied, there is no particular limitation on a channel selection mapping relationship for applying a channel selection method. For example, a channel selection mapping relationship for transmitting ACK/NACK information as shown in tables 8 to 10 may be defined. Table 8 defines a mapping relationship for 2-bit ACK/NACK, table 9 defines a mapping relationship for 3-bit ACK/NACK, and table 10 defines a mapping relationship for 4-bit ACK/NACK.

[ Table 8]

[ Table 9]

[ Table 10]

Alternatively, a channel mapping relationship for 1-bit to 4-bit ACK/NACK as shown in table 11 may be defined. In the example of table 11, one channel resource h0 and constellation values 1 and-1 generated through data modulation may be used to transmit 1-bit ACK/NACK information. For the transmission of 2-bit ACK/NACK information, two channel resources h0 and h1 and constellation values 1, -j, and j are used. For 3-bit ACK/NACK information, three channel resources h0, h1, and h2 and constellation values 1, -j, and j generated by data modulation are used. The four channel resources h0, h1, h2, and h3 and constellation values 1, -j, and j generated through data modulation may be used to transmit 4-bit ACK/NACK information.

[ Table 11]

UL ACK/NACK for DL transmission in a multi-carrier support system

In a multicarrier system or a CA support system, DL resources may be defined as DL CCs and UL resources may be defined as UL CCs. In addition, a combination of DL resources and UL resources may be referred to as a cell. A cell may refer to only a DL CC (or an UL CC) if the DL CC and the UL CC are asymmetrically configured. For example, if a specific UE is configured with one serving cell, there are one DL CC and one UL CC. However, if a specific UE is configured with two or more serving cells, there are DL CCs equal in number to the cells and UL CCs equal in number to or less than the DL CCs. When a specific UE is configured with a plurality of serving cells, a multicarrier environment in which the number of UL CCs is greater than the number of DL CCs may be supported.

The association between carrier frequencies of DL and UL resources (center frequencies of cells) may be indicated by system information transmitted on the DL resources. For example, the combination of DL resources and UL resources may be configured by association defined by SIB 2.

According to the above definition, CA may refer to a set of two or more cells having different carrier frequencies. That is, a case in which a specific UE is configured with two or more serving cells having different carrier frequencies may be referred to as a CA environment. For a UE supporting CA, one or more scells may be aggregated with a PCell to support increased bandwidth.

In this case, the serving cell may be a PCell or an SCell. For a UE in RRC _ CONNECTED state that does not support CA, there is only one serving cell including the PCell. Meanwhile, for a UE in an RRC _ CONNECTED state configured with CA, a serving cell refers to a set of one or more cells including a PCell and an SCell.

The PCell is a central cell controlling related communications among serving cells configured in a CA environment. The PCell is a cell indicated or used by the UE in an initial connection setup procedure, a connection re-establishment procedure, or a handover procedure. In LTE-a release 10, a UE may receive and transmit PUCCH only on its PCell. In future releases, PUCCH transmission on the SCell of the UE may be allowed. In addition, the UE may perform a monitoring procedure for system information acquisition and change only on the PCell. For the CA supporting UE, the BS may be changed only through a handover procedure using an RRCConnectionReconfiguration message including mobilityControlInfo.

Next, the SCell refers to a cell other than the PCell among serving cells configured in the CA environment. In LTE-a release 10, there is no PUCCH on SCell. If the SCell is added, the BS may provide all system information related to operation on the SCell in RRC _ CONNECTED state to the CA-capable UE through dedicated signaling. For the SCell, the change in system information may be performed by the release and addition of the SCell via one RRCConnectionReconfiguration message. The BS may transmit dedicated signaling to the UE with parameters different from those included in the broadcast message on the SCell. After the initial security activation procedure, the BS may configure one or more scells for the UE in addition to the PCell (the cell configured as the serving cell during the connection establishment procedure). The PCell may be used to provide security input and higher layer system information, and the SCell may be used to provide additional DL resources and, when necessary, UL resources. The BS may independently add, eliminate, or correct the SCell through the RRC connection reconfiguration procedure using the RRCConnectionReconfiguration message including or not including the mobilityControlInfo.

In a CA environment, PhyCellId, scelllindex, and ServCellIndex may be defined as RRC-related parameters/Information Elements (IEs). PhyCellId may have an integer ranging from 0 to 503 and may be used as a physical layer identifier of a cell. Scelllindex may have an integer ranging from 1 to 7, and may be used as an identifier of an SCell. The ServCellIndex may have an integer ranging from 0 to 7 and may be used as an identifier of a serving cell (PCell or SCell). The ServCellIndex having a value of 0 may be applied to the PCell, and for the SCell, the scelllindex may be applied. That is, a cell having the smallest (or lowest) cell index in the ServCellIndex may be defined as PCell.

In summary, a plurality of carriers in CA may be divided into PCell and SCell as UE-specific parameters. A particular UE may have one or more configured serving cells. If there are multiple configured serving cells, the cell with the smallest ServCellIndex among the cells is the PCell, and the other cells are scells. In LTE-a release 10, if a UE has multiple configured serving cells in TDD, UL-DL configurations constituting UL subframes and DL subframes in a frame may be the same in all cells, and HARQ-ACK timing indicating which UL subframe is used to transmit ACK/NACK for a PDSCH transmitted in a specific DL subframe may be the same in all cells according to the UL-DL configurations. In future releases, if the UE has multiple configured serving cells in TDD, the UL-DL configuration may differ between cells, and HARQ-ACK timing according to the UL-DL configuration may differ between cells.

In addition, the UE may transmit UCI such as CSI (including CQI, RI, PMI, etc.) and HARQ ACK/NACK measured from one or more CCs to the BS in one predetermined CC. For example, if multiple ACK/NACK feedbacks are required, the UE may collect ACK/NACK feedbacks (e.g., ACK/NACK multiplexing or ACK/NACK bundling) received from the PCell DL CC and one or more SCell DL CCs, and may transmit the collected ACK/NACK feedbacks to the BS in the UL CC of the PCell using one PUCCH.

In the present invention, when a plurality of ACK/NACK signals for a plurality of DL transmissions are transmitted through one PUCCH, a unit (one or more subframes and/or one or more carriers) constituting the plurality of DL transmissions is referred to as a bundling window. That is, time domain bundling refers to ACK/NACK signals for DL transmission bundled in multiple subframes. The CC domain bundling refers to ACK/NACK signals for DL transmission bundled in a plurality of CCs. Time domain/CC domain bundling refers to ACK/NACK signals for DL transmission bundled in multiple subframes and multiple CCs. Although ACK/NACK bundling may be performed by a logical and operation, the present invention is not limited thereto and other operations such as a logical or may be used.

In addition, a unit for actually performing time domain bundling and/or CC domain bundling using a logical and (or logical or) operation may be referred to as an actual bundling window. That is, one or more actual bundling windows may exist in one bundling window. In other words, the size of the bundling window is equal to or larger than the size of the actual bundling window. Here, spatial bundling for a plurality of ACK/NACK bits for one DL transmission (i.e., ACK/NACK bundling for a plurality of codewords) may be applied regardless of a bundling window or an actual bundling window.

An example of ACK/NACK required for DL transmission defined in the 3GPP LTE system will now be described. Here, when ACK/NACK is transmitted in subframe n, the ACK/NACK is correlated with DL transmission in subframe n-k.

In a TDD system, with respect to the relationship between subframe n and subframe n-K, as shown in table 12, a DL correlation set index K may be given for each UL-DL configuration of table 1: { k } is a function of₀,k₁,…k_M-1}。

[ Table 12]

In FDD, M is always 1, and K always satisfies { K }₀4. When transmitting ACK/NACK for DL transmission in subframe n-k in subframe n, the DL transmission in subframe n-k may correspond to one or more of the following three cases.

Case 1 is when ACK/NACK feedback for one or more PDSCHs indicated by one or more PUCCHs detected in one or more subframes n-k is required. Here, K ∈ K, and K varies according to a subframe index n and UL-DL configuration, and includes M elements { K ∈₀,k₁,...k_M-1}. Table 12 below shows K: { k } is a function of₀,k₁,...k_M-1}. Case 1 relates to one or more PDSCHs requiring normal ACK/NACK feedback. In the following description, case 1 is referred to as 'ACK/NACK for PDSCH' or 'ACK/NACK for PDSCH with PDCCH'.

Case 2 is when ACK/NACK feedback is needed for one or more PDCCHs indicating DL SPS release in one or more subframes n-k. Here, K ∈ K, and K denotes the same index as in the description given in case 1. The ACK/NACK of case 2 denotes ACK/NACK feedback for one or more PDCCHs for SPS release. Meanwhile, when ACK/NACK feedback for DL SPS release is performed, ACK/NACK feedback for one or more PDCCHs indicating SPS activation is not performed. In the following description, case 2 is referred to as 'ACK/NACK for DL SPS release PDCCH'.

Case 3 is when ACK/NACK feedback for transmission of one or more PDSCHs is required, where there is no corresponding one or more PDCCHs detected in one or more subframes. Here, K ∈ K, and K denotes the same index as in the description given in case 1. Case 3 relates to PDSCH without PDCCH and represents ACK/NACK feedback for PDSCH allocated by SPS. In the following description, case 3 is referred to as 'ACK/NACK for DL SPS PDSCH'.

In the following description, PDSCH with corresponding PDCCH, PDSCH for DL SPS release, and PDSCH without corresponding PDCCH are collectively referred to as DL transmission requiring ACK/NACK transmission.

An example of the present invention when the above ACK/NACK for DL transmission is applied to a multi-carrier system will be described in detail below.

For convenience of explanation, examples of the present invention will be described under the following assumptions. However, the embodiments of the present invention are not limited to the following assumptions.

(1) There may be one PCell and one or more scells.

(2) There may be a PDSCH with a corresponding PDCCH on the PCell and one or more scells.

(3) There may be a PDCCH indicating DL SPS release only on the PCell.

(4) There may be only a PDSCH without a corresponding PDCCH on the PCell (═ SPS PDSCH).

(5) Cross scheduling from the PCell to one or more scells may be supported.

(6) Cross-scheduling from one or more scells to PCell is not supported.

(7) Cross-scheduling from one or more scells to another SCell (or other scells) may be supported.

In the description of the present invention, time domain bundling and/or CC domain bundling represents a logical and operation. However, the time domain bundling and/or the CC domain bundling may be performed by other methods such as a logical or operation, etc. That is, time domain bundling or CC domain bundling refers to a method for expressing a plurality of ACK/NACKs over a plurality of subframes or CCs as ACK/NACK information having fewer bits in an ACK/NACK response using a single PUCCH format. In other words, time domain bundling or CC domain bundling refers to any method for expressing M-bit ACK/NACK information as N bits (M ≧ N).

In a system to which multi-carrier and/or TDD is applied, a plurality of ACK/NACK bits may be transmitted through channel selection using PUCCH format 1a/1b, PUCCH format 3, or channel selection using PUCCH format 3. For PUCCH resource index for PUCCH format, implicit mapping, explicit mapping, or a combination of implicit and explicit mapping may be used. The implicit mapping may use a method for deriving a PUCCH resource index based on the lowest CCE index of a corresponding PDCCH. The explicit mapping may use a method of indicating or deriving a PUCCH resource index in a set predetermined by RRC configuration through an ACK/NACK resource indicator (ARI) in the PDCCH.

In relation to the present invention, when a new format (e.g., PUCCH format 3 described with reference to fig. 24 to 27) for transmitting a plurality of ACK/NACK bits, resource allocation of PUCCH format 3 is basically performed based on explicit resource allocation.

Specifically, a UE configured as PUCCH format 3 may be explicitly assigned (e.g., through RRC signaling) orthogonal resources for that format. In addition, a final PUCCH resource may be determined by an ARI value of a DCI format in a PDCCH for a PDSCH transmitted on an SCell among orthogonal resources predetermined by RRC configuration. In this case, the ARI may be used as an offset based on the explicitly signaled PUCCH resource value or may be used to indicate which of one or more PUCCH resource sets to use.

In order to include ARI information in the PDCCH, a method of reusing a field defined in a DCI format of an existing PDCCH for ARI purposes may be considered. The PDCCH may include a Transmit Power Control (TPC) field. The TPC field is originally intended to control the transmission power of the PUCCH and/or PUSCH and may be composed of 2 bits.

As described above, when the ARI is transmitted only on the SCell, the TPC field in the PDCCH on the SCell may be reused as the ARI. Meanwhile, the TPC field in the PDCCH on the PCell may be used for transmission power control of the PUCCH and/or PUSCH.

In the LTE rel-10 system, since a PDCCH for scheduling a PDSCH of a PCell cannot be received on an SCell (i.e., cross-carrier scheduling of the PDSCH of the PCell is not allowed from the PDCCH of the SCell), the meaning that a UE receives the PDSCH only on the PCell may be equivalent to the meaning that the UE receives the PDCCH only on the PCell.

Explicit ACK/NACK resource allocation configured by RRC signaling may be performed as follows.

First, a PDCCH corresponding to a PDSCH (i.e., a PDCCH for scheduling a PDSCH) on an SCell may include information (e.g., ARI) for deriving a specific PUCCH resource from one or more RRC-configured resources.

Next, if a PDCCH corresponding to a PDSCH is not received on the SCell and the PDSCH is received only on the PCell, one of the following cases may be applied. First, PUCCH resources (i.e., PUCCH formats 1a/1b) defined in LTE release 8 may be used. Second, a PDCCH corresponding to a PDSCH on a PCell may include information (e.g., ARI) for deriving a specific PUCCH resource from one or more RRC-configured resources.

The UE may assume that all PDCCHs corresponding to the PDSCH on the SCell have the same ARI.

In this way, when ARI information is defined to be transmitted only on the SCell, if the UE receives only one or more PDSCHs for the PCell (or receives one or more PDCCHs only on the PCell) in a multi-carrier and/or TDD system, a final resource index for a PUCCH format (PUCCH format 3) to be used by the UE cannot be determined because the UE cannot know ARI information transmitted from the SCell.

The present invention devised to solve the above problem proposes a method for determining a final resource index for a PUCCH format even when a UE receives only one or more PDSCHs for a PCell (or receives one or more PDCCHs only on the PCell).

In various examples of the present invention, for convenience of explanation, a case in which a UE receives only one or more PDSCHs for a PCell (or a case in which the UE receives only one or more PDCCHs on the PCell) is simply referred to as 'PCell-only reception'. Here, reception with respect to the UE defines PCell reception only. If the present invention is applied to a multi-carrier environment, the UE may have one configured cell or a plurality of configured cells. If the UE has one configured cell, the cell may be a PCell, and if the UE has a plurality of configured cells, the cell may be composed of one PCell and one or more scells. The present invention can be applied to either or both of these cases. That is, the PCell-only reception case may be applied to the CA environment and the non-CA environment.

Also, as described above, a new PUCCH format, i.e., PUCCH format 3, may be used for ACK/NACK transmission for DL transmission received through a plurality of DL subframes in the TDD system, even when the UE includes one configured cell. PUCCH format 3 may also be used in FDD or TDD systems when the UE includes multiple configured cells. That is, PUCCH format 3 may be used in a CA system or a non-CA tdd system.

Also, in various examples of the invention, the candidate resource set for PUCCH format 3 may be RRC-configured. A specific PUCCH resource in the PUCCH resource candidate set may be determined by or derived from a value of ARI information (which may be expressed as reuse of a TPC field of a PDCCH). In short, PUCCH format 3 resources to be used by the UE are derived from ARI included in the PDCCH among RRC-configured resource candidates. When the ARI is expressed by reuse of the TPC field (2-bit size) of the PDCCH on the SCell as described above, the ARI has a size of X bits, and X may be defined as 2. For example, one resource of four PUCCH resource candidates may be expressed using a 2-bit ARI.

For convenience of explanation associated with the application of PUCCH format 3, the present invention is described under the assumption that transmission is performed through a single antenna requiring one orthogonal resource. However, it is apparent that the present invention is not limited thereto, and the principles of the present invention are applicable in the same manner even when a multi-antenna transmit diversity scheme such as Spatial Orthogonal Resource Transmit Diversity (SORTD) is applied to the PUCCH format 3.

Now, exemplary assumptions of the present invention for PUCCH format 3 resource allocation are described based on the above description.

The resource for PUCCH format 3 may be expressed asAnd four orthogonal resource candidates for PUCCH format 3 may be expressed as

And

any UE may be assigned such four orthogonal resources through RRC signaling. The RRC signaling may be, for example, four separate RRC signals. The UE can be informed of one set of four orthogonal resources through one RRC signaling

The UE, which has been assigned four PUCCH resource candidates, may finally determine one PUCCH resource among the four PUCCH resource candidates based on the value indicated by the additionally received ARI

Table 13 below shows exemplary resource allocation for PUCCH format 3 in single antenna transmission.

[ Table 13]

Hereinafter, various embodiments of the present invention are described in detail based on the above description.

Example 1

The present embodiment 1 relates to a method of using a predefined resource allocation in a PCell-only reception case (i.e., a case of receiving only one or more PDSCHs for a PCell or a case of receiving only one or more PDCCHs on a PCell).

In case of PCell-only reception, a resource index of PUCCH format 3 can be determined. That is, in case of non-PCell-only reception, the UE may derive a PUCCH resource index from ARI received on the SCell, while in PCell-only reception, the UE may use a predetermined PUCCH resource index.

Specifically, a new index may be predetermined so that the UE can determine PUCCH format 3 resources to be used in case of PCell-only reception. The new index may have the same meaning as ARI on SCell. In other words, the index may be used to indicate any one of resource candidate sets configured through RRC signaling. The index may be defined in the form of a predefined rule (or a specific value) for indicating a specific ordered resource (e.g., the first resource or the last resource) in the resource candidate set.

For example, in the PCell-only reception case, an index capable of determining PUCCH format 3 resources may be defined as a system-specific value. Alternatively, the index may be RRC-configured to be eNB-specific or UE-specific.

Fig. 28 is a flowchart illustrating a predefined resource allocation for PUCCH resource determination in case of PCell-only reception.

In step S2810, the UE may receive a PUCCH resource candidate set including four resources for PUCCH format 3 through higher layer configuration (e.g., RRC signaling)

In step S2820, when PUCCH format 3 is used for ACK/NACK transmission, the UE may determine whether the situation is a PCell-only reception case. If the determined result at step S2820 is no (i.e., not the PCell-only reception case), step S2830 is performed, and if yes (i.e., the PCell-only reception case), step S2840 is performed.

In step S2830, the UE may calculate/select one PUCCH resource (i.e., one resource index) to be used by it from four PUCCH resource candidates using an ARI indicated by reuse of a TPC field in one or more PDCCHs of the SCell.

At the same time, becauseIn order not to receive the PDCCH on the SCell in step S2840, the UE may select one PUCCH resource from among the four PUCCH resource candidates according to a predefined rule (or a predefined index). In the illustrated example of fig. 28, the predefined rule is to select the last PUCCH resource index in the PUCCH resource candidate set. That is, in step S2840, the UE may calculate/select

After step S2830 or step S2840, the UE may transmit ACK/NACK information through PUCCH format 3 using a resource corresponding to the calculated/selected index.

Example 2

This embodiment 2 relates to a method for predetermining an additional resource index and using the additional resource index for PUCCH resource allocation in case of PCell-only reception (i.e., case of receiving only PDSCH(s) for PCell or case of receiving only PDCCH(s) on PCell).

In case of PCell-only reception, an additional resource index of PUCCH format 3 can be predetermined. That is, the UE may derive a PUCCH resource index from an ARI received on an SCell in case of non-PCell-only reception, and the UE may use a predetermined additional PUCCH resource index in case of PCell-only reception. The predetermined index in the above embodiment 1 is a predetermined index for one of PUCCH resource candidates configured for the UE, and the embodiment 2 is different from the embodiment 1 in that: additional resource indices separate from PUCCH resource candidates configured for the UE are predetermined.

According to this embodiment, for example, if a 2-bit ARI is used and a set of four RRC-configured resource candidates is defined, one further resource candidate may be signaled to the UE by RRC signaling. Then, the RRC-configured resource candidate set includes 5 PUCCH resource indexes, and one predetermined resource index (e.g., the last index) among them may be defined to be used only in the PCell-only reception case. Alternatively, one resource candidate for PCell-only reception may be defined separately from four PUCCH resource candidates. In both of the above two cases, the UE may be allocated a reserved resource index only for the PCell-only reception case (i.e., a resource index that is not specified by the ARI on the SCell). Here, although it is preferable that one additional resource candidate for PCell-only reception is not overlapped with four existing RRC-configured resource candidates, the overlapping may be allowed in some cases.

Fig. 29 is a flowchart illustrating additional predefined resource allocations determined for PUCCH resources in a PCell-only reception case.

In step S2910, the UE may receive a PUCCH resource candidate set including four resources for PUCCH format 3 through higher layer configuration (e.g., RRC signaling)

In step S2920, when PUCCH format 3 is used for ACK/NACK transmission, the UE may determine whether the situation is a PCell-only reception case. If the determination result in step S2920 is no (i.e., not the PCell-only reception case), step S2830 is performed, and if yes (i.e., the PCell-only reception case), step S2940 is performed.

In step S2930, four PUCCH resource candidates (for example, four low-index PUCCH resources) predetermined according to a prescribed rule from the 5 PUCCH resource candidates are selected

) In this case, the UE may select the four PUCCH resource candidates using the ARI indicated by reuse of the TPC field in the PDCCH or PDCCHs of the SCell

One PUCCH resource to be used by it is calculated/selected.

Meanwhile, since the PDCCH is not received on the SCell in step S2940, the UE may select one PUCCH resource according to a predefined rule. The predefinedThe rule may be for selecting the last resource from 5 RRC configured PUCCH resource candidates

The rule of (2). It may be defined that the rule for determining four out of 5 PUCCH resource candidates in step S2930 is not overlapped with the rule for determining one out of 5 PUCCH resource candidates in step S2940. However, in some cases, rules may be defined such that overlapping resource candidates are selected.

After step S2930 or step S2940, the UE may transmit ACK/NACK information through PUCCH format 3 using a resource corresponding to the calculated/selected index.

Example 3

Embodiment 3 relates to a method of using a Downlink Assignment Index (DAI) for PUCCH resource allocation in a PCell-only reception case, i.e., a case of receiving only one or more PDSCHs for a PCell or a case of receiving only one or more PDCCHs on a PCell.

In the above-described

embodiments

1 and 2, the method for deriving the resource index for the PUCCH format 3 in PCell-only reception without using additional physical layer signaling (e.g., PDCCH signaling) has been described. Embodiment 3 relates to a method of defining and using information capable of performing a function of ARI in a physical layer signal received on a PCell, although ARI cannot be received on an SCell as in the existing scheme, since there is no PDCCH on the SCell. Specifically, the embodiment relates to a method of using DAI information included in a PDCCH as ARI information in a PCell-only reception case.

A DAI field in a PDCCH is defined in a TDD system, and is assigned with respect to DL allocation (or PDSCH scheduling). When the UE transmits ACK/NACK signals for a plurality of DL assignments (PDSCHs) in one UL subframe, information on the number of DL assignments (PDSCHs) for which the ACK/NACK signals are to be transmitted can be derived from the DAI. For example, when the UE transmits ACK/NACK signals (using ACK/NACK bundling) for multiple DL assignments (PDSCHs) to the BS, a situation may occur in which the UE fails to receive (i.e., loses) a portion of the multiple PDCCHs. At this time, since the UE cannot know a case to which the PDSCH corresponding to the PDCCH of which reception failed has been transmitted, an error may occur in ACK/NACK generation. DAI may be used to solve such problems. In the existing TDD system, for example, in a case where one UL subframe corresponds to N DL subframes, if DAIs are sequentially assigned (i.e., sequentially counted) to PDCCHs transmitted in the N DL subframes, the UE can know whether a previous PDCCH has been correctly received through DAI information in the PDCCHs.

In this embodiment, considering the case where the DAI in the PDCCH of PCell is not used for the original purpose when PUCCH format 3 is used, it is proposed to reuse the DAI as an ARI for determining PUCCH resource assignment. Specifically, even though PUCCH format 3 is used in the TDD system, DAI information is not required in operation as an ACK/NACK full multiplexing mode in which time domain bundling or CC domain (or frequency domain) bundling is not performed. Therefore, the DAI field may be reused as an ARI for PCell-only reception.

Fig. 30 is a flowchart illustrating an example of using a DAI field as an ARI for PUCCH resource determination in a PCell-only reception case.

In step S3010, the UE may receive a PUCCH resource candidate set including four resources for PUCCH format 3 through higher layer configuration (e.g., RRC signaling)

In step S3020, when PUCCH format 3 is used for ACK/NACK transmission, the UE may determine whether the situation is a PCell-only reception case. If the determination result in step S3020 is no (i.e., not the PCell-only reception case), step S3030 is performed, and if yes (i.e., the PCell-only reception case), step S3040 is performed.

In step S3030, the UE may calculate/select one PUCCH resource (i.e., one resource index) to be used by it from the four PUCCH resource candidates using ARI indicated by reuse of the TPC field in one or more PDCCHs of the SCell.

Meanwhile, in step S3040, since the PDCCH is not received on the SCell, the UE may select one PUCCH resource (i.e., one resource index) to be used by it from among the four PUCCH resource candidates using the ARI indicated by reuse of the DAI field in the PDCCH of the PCell.

After step S3030 or step S3040, the UE may transmit ACK/NACK information through a PUCCH format using resources corresponding to the calculated/selected index.

Example 3-1

Embodiment 3-1 relates to an example of applying the same ARI value in bundled subframes in a PCell-only reception case (i.e., in a case of receiving only one or more PDSCHs for a PCell or in a case of receiving only one or more PDCCHs on a PCell).

The term bundling subframe (or bundling window) used in the description of the present invention denotes one unit consisting of DL subframes when ACK/NACK responses to the DL subframes in the bundling window are transmitted through one UL PUCCH, rather than a unit in which bundling is actually performed in a time domain or a CC domain (or a frequency domain).

For example, in an LTE Release 8 TDD system, as in Table 12 above (showing DL correlation set index K: { K:)₀,k₁,…k_M-1}), a definition is given as to which previous DL subframe(s) (subframe n-k) to use to transmit an ACK/NACK response for a DL transmission in a particular UL subframe (subframe n). In describing bundling subframes by way of example of table 12, when ACK/NACK responses for DL transmissions in one or more specific DL subframes are transmitted in the specific UL subframe, the one or more specific DL subframes are referred to as bundling subframes. For example, in UL-DL configuration 4, the bundling subframes for UL subframe 2 are

DL subframes

12, 8, 7, and 11, and the bundling subframes for UL subframe 3 are

DL subframes

6, 5, 4, and 7.

If PUCCH format 3 is used in TDD, ACK/NACK responses for DL transmission in a plurality of DL subframes may be transmitted through one UL PUCCH as described above. Here, when one or more PDCCHs are detected in a plurality of DL subframes in the PCell-only reception case according to embodiment 3, if ARI (or DAI) values indicated by the respective PDCCHs are different, it is unclear which ARI value is used for calculating/selecting a PUCCH resource.

To prevent this problem, the ARI value (i.e., the value of the DAI field) of the PDCCH transmitted on the PCell in the bundled subframe should be maintained identically.

Examples 3 to 2

Embodiment 3-2 relates to an example of applying the same ARI value in a bundled CC. This embodiment may also be applied to the PCell-only reception case, which may include the following cases: wherein the UE cannot detect DL transmission on the one or more scells and receives DL transmission only on the PCell, although the BS has performed DL transmission on the PCell and the one or more scells.

The term bundling subframe (or bundling window) used in the description of the present invention denotes one unit consisting of DL CCs when ACK/NACK responses for the DL CCs in the bundling window are transmitted through one UL PUCCH regardless of the presence/absence of bundling, not a unit in which bundling is actually performed in a time domain or CC domain (or frequency domain). For example, when ACK/NACK full multiplexing is applied, the bundled CCs may have the same meaning as the number of CCs configured for the UE.

If PUCCH format 3 is used in a TDD or FDD system, a case in which ACK/NACK responses for a plurality of DL CCs are transmitted through one ul PUCCH may occur as described above. Here, the meaning of 'transmitting ACK/NACK responses for multiple DL CCs' may indicate that there is DL transmission in the PCell and one or more scells. At this time, if the ARI value in the PDCCH of the PCell is different from that in the PDCCH of the SCell, it is unclear which ARI value is used to calculate/select the PUCCH resource.

Therefore, in order to prevent the above problem, the value of a field for ARI purpose (DAI field) on the PCell and the value of a field for ARI purpose (TPC field) on the SCell should be maintained identically.

Examples 3 to 3

Embodiment 3-3 relates to an example of applying the same ARI value in bundling CCs and subframes.

When both embodiments 3-1 and 3-2 are considered (e.g., when a plurality of CCs and a plurality of subframes are one bundling unit), if ARI values in corresponding cells or corresponding subframes are different, the calculation/selection of PUCCH resources may not be clear. Therefore, ARI values in PDCCHs in a plurality of subframes are kept equal, except that ARI values in PDCCHs are kept equal on a PCell and an SCell.

Example 4

Embodiment 4 relates to a method of using a TPC field for PUCCH resource allocation in a PCell-only reception case (i.e., a case of receiving only one or more PDSCHs for a PCell or a case of receiving only one or more PDCCHs on a PCell). Embodiment 4 can be applied to both cases in which ACK/NACK full multiplexing is applied or not applied. Embodiment 4 can also be applied to both cases in which spatial bundling (ACK/NACK bundling for multiple codewords) is applied or not applied.

In the above embodiment 3, a method for determining a resource index of a PUCCH resource (e.g., a resource of PUCCH format 3) even in PCell-only reception without using additional physical layer signaling has been described. Embodiment 3 relates to an example of using DAI for ARI purpose when it is not used as original purpose (purpose of sequentially assigned index for DL allocation (or PDSCH scheduling)). Therefore, when PUCCH format 3 is used in a TDD system, if time domain bundling or CC domain (or frequency domain) bundling is supported, DAI information is required for an original purpose in order to generate correct ACK/NACK information.

Therefore, in embodiment 4, the DAI is not used for other purposes in the PCell-only reception case. This embodiment 4 proposes a method of reusing the TPC field in one or more PDCCHs on the PCell as an ARI in the PCell-only reception case.

In the non-PCell-only reception case (i.e., there is PDCCH transmission on the SCell), the TPC field on the SCell is reused for ARI as described above. However, in the PCell-only reception case, since there is no transmission of the TPC field on the SCell, a new method for transmitting correct ACK/NACK must be defined.

According to embodiment 4, in a PCell-only reception case, the TPC field in one or more specific PDCCHs determined according to a predetermined rule on the PCell may be used for original transmit power control purposes and the TPC field of one or more additional PDCCHs may be used for ARI purposes. The UE may use only the TPC field of one or more specific PDCCHs determined according to a predetermined rule on the PCell for original power control purposes, and upon receipt of other one or more PDCCHs on the PCell, the UE may interpret the TPC field of one or more corresponding PDCCHs as an ARI.

The UE may lose the PDCCH including the TPC field for power control if the TPC field is not used for the original purpose, or may slightly degrade the dynamic control performance for UL transmit power determination of the UE if the PDCCH is not scheduled by the BS. However, the TPC value in the PDCCH is not an absolute value but a relative offset value to the previous transmission power. Also, the preset transmit power may be maintained even if the UE does not update the TPC value once or twice. In addition to the transmit power control method using the TPC field in the PDCCH, a supplementary power control method is provided (which deviates from the scope of the present invention and therefore, will not be described in detail). Thus, the loss of TPC values does not have a significant impact on network performance.

In applying the present invention, the TPC field of one or more PDCCHs on the PCell according to a predetermined rule may be used for an original purpose (power control purpose). Hereinafter, an example of the predetermined rule will be described.

As a first example, a TPC field of a PDCCH transmitted in an nth subframe of a bundled subframe may be defined for an original purpose. Here, n may be a value indicating one or more subframes in a part of the bundled subframes. For example, if one of the bundled subframes is indicated, n may be determined as a value indicating 0 th subframe or the last subframe. Also, n may be differently determined according to the number of bundled subframes (or the size of bundled subframes). In a similar manner as shown in table 12, the number of bundled subframes may be, for example, 1, 2, 3, 4, or 9. Alternatively, a different number of subframes may be bundled according to a newly defined bundling scheme. Also, n may indicate a set of a plurality of subframes in the bundled subframe. For example, when n is 0 and 1, TPC fields of PDCCHs transmitted in 0 th and 1 st subframes in a bundled subframe may be used for original purposes. Accordingly, if n has a plurality of values, the number of PDCCHs to be received for a backoff test described below is increased by the number of n values. For example, if n has two values, the number of PDCCHs received for the fallback test should be 2. In the following exemplary description of the present invention, n has one value for convenience of description.

As a second example, a TPC field in a PDCCH having an nth DAI value in a bundled subframe may be defined for an original purpose. Here, n may be one of 0,1, 2, 3. Alternatively, if the DAI value is interpreted as 1, 2, 3, 4, then n may be determined to be a value of 1, 2, 3, 4. In this case, even in an ACK/NACK full multiplexing mode (a case in which time domain or CC domain (or frequency domain) bundling is not applied), a DAI field may be included in one or more PDCCHs on the PCell. Also, n may be determined in the form of a set of a plurality of values. For example, when n is 0 and 1, this may indicate that the TPC field in the PDCCH having the zeroth and first DAI values is used for the original purpose. Alternatively, when interpreting the DAI value as starting from 1, if n is 1 and 2, the TPC field in the PDCCH having the first and second DAI values may be indicated as being used for the original purpose. Accordingly, when n has a plurality of values, the number of PDCCHs received for a backoff test described later is increased by the number of n values. For example, if n has two values, the number of PDCCHs received for the fallback test should be 2. In the following description of the present invention, n has one value as an example for convenience of description.

In the second example above, the DAI value may represent a consecutive (sequential) counter for one or more PDCCHs allocated to the UE in a two-bit size. The actually transmitted value of the DAI field may be one of 0,1, 2, and 3 (or 00, 01, 10, and 11 when expressed as a 2-bit value) that may be interpreted by the UE as DAI values 1, 2, 3, and 4. The following description will be made with respect to the actually transmitted DAI value and the DAI value interpreted by the UE.

The actually transmitted value of the DAI field may be 0,1, 2, or 3, and the UE may interpret the value as the first, second, third, or fourth PDCCH. In this case, with respect to the actually transmitted DAI value, n ═ 0 (in the set of 0,1, 2, and 3) in a specific UE indicates the first PDCCH.

The actually transmitted value of the DAI field may be 0,1, 2, or 3, and the UE may interpret the value as the first, second, third, or fourth PDCCH. In this case, with respect to the DAI value interpreted by the UE, n ═ 1 (in the set of 1, 2, 3, and 4) in a specific UE indicates the first PDCCH.

In summary, the actual DAI values 00, 01, 10, and 11 included in the PDCCH may be mapped to DAI values 1, 2, 3, and 4, respectively, interpreted by the UE.

As described in the above example, the TPC field in one or more PDCCHs of the nth subframe or one or more PDCCHs of DAI ═ n determined by the value of n is used for the original purpose (power control), and the TPC field in the other one or more PDCCHs may be reused as the ARI.

Fig. 31 is a flowchart illustrating an example of using a TPC field as an ARI for PUCCH resource determination in a PCell-only reception case. In the example of fig. 31, it is assumed that the TPC field of one specific PDCCH determined according to a predefined rule is used for an original purpose, and the TPC field of other one or more PDCCHs is reused as an ARI.

In step S3110, the UE may receive a PUCCH resource candidate set including four resources for PUCCH format 3 through higher layer configuration (e.g., RRC signaling)

In step S3120, when PUCCH format 3 is used for ACK/NACK transmission, the UE may determine whether the situation is a PCell-only reception case. If the determined result in step S3120 is no (i.e., not the PCell-only reception case), step S3130 is performed, and if so (i.e., the PCell-only reception case), step S3140 is performed.

In step S3130, the UE may calculate/select one PUCCH resource (i.e., one resource index) to be used by it from four PUCCH resource candidates using an ARI indicated by reuse of a TPC field in one or more PDCCHs of the SCell.

Meanwhile, in step S3140, the UE may determine whether the number of received PDCCHs is 1. Since step S3140 is performed when the PDCCH is not received on the SCell, the number of received PDCCHs indicates the number of PDCCHs received on the PCell. If the determination result in step S3140 is yes (i.e., the number of PDCCHs received on the PCell is 1), step S3150 is performed, and if the determination result in step S3140 is no (i.e., the number of PDCCHs received on the PCell is greater than 1), step S3160 is performed.

In step S3150, if the UE receives only one PDCCH on the PCell, the UE may use the TPC field of the PDCCH for an original purpose (power control), and since there is no other PDCCH, the UE may determine that an ARI value is not received. In this case, the UE is defined to operate in the legacy LTE release 8 mode. This may be referred to as operation in a fallback mode. The fallback mode is the same as the ACK/NACK transmission operation using the conventionally defined PUCCH format 1a/1b, and thus, a detailed description thereof will be omitted. The determination as to whether the number of received PDCCHs is 1 in step S3140 may be referred to as a fallback test, in which it is determined whether a fallback mode is applied.

Meanwhile, since step S3160 is performed when the number of PDCCHs received on the PCell is greater than 1, the UE may use the TPC field in one of the PDCCHs for original use purposes and may interpret the TPC field of the other one or more PDCCHs as being used for the ARI. Then, the UE may calculate/select one PUCCH resource (i.e., one resource index) to be used by it from the four PUCCH resource candidates using the ARI indicated by reuse of the TPC field in the PDCCH of the PCell.

After step S3130 or step S3160, the UE may transmit ACK/NACK information through PUCCH format 3 using a resource corresponding to the calculated/selected index.

In the illustrated example of fig. 31, the explanation has been given under the following assumption: the UE views only the number of received (or detected) PDCCHs, and when the number of received PDCCHs is 1, the TPC field of the corresponding PDCCH is used for the original purpose.

However, if the number of received PDCCHs is 1, the TPC field of the PDCCH may be used for an original purpose or may be reused for an ARI purpose. Therefore, when the number of received PDCCHs is 1, the fallback mode operation is not always performed, and it is preferable to perform detailed determination.

Fig. 32 is a flowchart illustrating another example of using a TPC field as an ARI for PUCCH resource determination in case of PCell-only reception. In the example of fig. 31, it is assumed that the TPC field of one specific PDCCH determined according to a predefined rule is used for an original purpose, and the TPC field of other one or more PDCCHs is reused as an ARI.

In the illustrated example of fig. 32, the description of the same operations (steps S3210, S3220, S3230, and S3240) as those of fig. 31 is omitted.

Step S3250 is performed when the determination result of step S3240 is yes (i.e., when the number of PDCCHs received on the PCell is 1). In step S3250, it is determined whether the one received PDCCH is a predefined PDCCH (i.e., whether the TPC field of the PDCCH is used for an original purpose). For example, it may be determined whether the received PDCCH is a PDCCH in a first subframe of a bundled subframe. As another example, it may be determined whether the received PDCCH is a PDCCH having a DAI value of 1 (hereinafter, DAI ═ 1). If the determination result is yes, step S3260 is performed, and if not, step S3270 is performed.

In step S3260, since the TPC field in one received PDCCH should be used for the original purpose, the UE may consider ARI as unknown and may operate in a fallback mode (ACK/NACK transmission using PUCCH format 1a/1 b).

Step S3270 may be performed when the result of step S3240 is no. That is, if the number of received PDCCHs is greater than 1, the UE may recognize that the TPC field of at least one PDCCH is reused as the ARI because it is assumed that there is only one PDCCH in which the TPC field is used for the original purpose. The UE may calculate/select one PUCCH resource (i.e., one resource index) to be used by it among the four PUCCH resource candidates using an ARI value from the TPC field of the corresponding PDCCH.

When the determination result of step S3250 is no, step S3270 may also be performed. That is, if the number of received PDCCHs is 1, the UE may recognize that the TPC field of the corresponding one PDCCH is reused for the ARI because the corresponding PDCCH is not a PDCCH in which the TPC field is used for the original purpose. The UE may calculate/select one PUCCH resource (i.e., one resource index) to be used by it among the four PUCCH resource candidates using an ARI value from the TPC field of the corresponding PDCCH.

In step S3270, the UE may transmit ACK/NACK information through PUCCH format 3 using resources corresponding to the calculated/selected index.

Example 4-1

Embodiment 4 relates to an example of applying the same ARI value in bundled subframes in case of PCell-only reception (i.e., in case of receiving only one or more PDSCHs for PCell or receiving only one or more PDCCHs on PCell).

The term bundling subframe (or bundling window) used in the description of the present invention denotes one unit consisting of DL subframes when ACK/NACK responses to DL transmissions in DL subframes in the bundling window are transmitted through one UL PUCCH, rather than a unit in which bundling is actually performed in a time domain or CC domain (or frequency domain).

For example, in an LTE Release 8 TDD system, as in Table 12 above (showing DL correlation set index K: { K:)₀,k₁,…k_M-1}) a definition is given as to which previous DL subframe(s) (subframe n-k) were used to transmit ACK/NACK responses for the DL wireless communication system in a particular UL subframe (subframe n). In describing the bundling subframe by way of example of table 12, when an ACK/NACK response for DL transmission in a specific DL subframe or subframes is transmitted in the specific UL subframe or subframes, the specific DL subframe or subframes is referred to as a bundling subframe. For example, in UL-DL configuration 4, the bundling subframes for UL subframe 2 are

DL subframes

12, 8, 7, and 11, and the bundling subframes for UL subframe 3 are

DL subframes

6, 5, 4, and 7.

If PUCCH format 3 is used in TDD, ACK/NACK responses for DL transmission in a plurality of DL subframes may be transmitted through one UP PUCCH as described above. Here, according to the above-described embodiment 4, a plurality of PDCCHs are detected in a plurality of DL subframes in the case of PCell-only reception. If the ARI (or TPC) values indicated by the PDCCH with the TPC field reused as an ARI are different, it is ambiguous which ARI value is used for calculating/selecting the PUCCH resource.

Here, in addition to a PDCCH having a TPC field determined to be used for an original purpose according to a predefined rule, for example, a PDCCH having DAI ═ 1, a PDCCH having a TPC field reused as an ARI may correspond to a PDCCH (for example, a PDCCH having a DAI value greater than 1 (hereinafter, referred to as DAI > 1)).

Therefore, in order to prevent this problem, the ARI value (i.e., the value of the TPC field) of a PDCCH having a TPC field reused as an ARI (i.e., a PDCCH other than the PDCCH having the TPC field for the original purpose), which is transmitted on the PCell in a bundled subframe, should be equally maintained.

Example 4 to 2

Embodiment 4-2 relates to an example of applying the same ARI value on bundled CCs.

The term bundled CC (or bundling window) used in the description of the present invention denotes a unit consisting of DL CCs when ACK/NACK responses for DL CCs within the bundling window are transmitted through one UL PUCCH regardless of the presence/absence of bundling, rather than a unit in which bundling is actually performed in a time domain or a CC domain (or a frequency domain). For example, when ACK/NACK full multiplexing is applied, the bundled CCs may have the same meaning as the number of CCs configured for the UE.

If PUCCH format 3 is used in a TDD or FDD system, ACK/NACK responses for a plurality of DL CCs may be transmitted through one UL PUCCH as described above. Here, the meaning of transmitting ACK/NACK responses for multiple DL CCs may correspond to a case where there is DL transmission on a PCell and one or more scells. At this time, if the ARI value in the PDCCH having the TPC field used as ARI on PCell is different from that in the PDCCH on SCell, it is unclear which ARI value is used for calculating/selecting PUCCH resources.

Therefore, in order to prevent such a problem, a value of a field (TPC field) used as an ARI on the PCell and a value of a field (TPC field) used as an ARI on the SCell should be equally maintained.

Here, the ARI value on the PCell and the ARI value on the SCell may be maintained equally with the ARI value of a PDCCH (e.g., a PDCCH with DAI >1) other than a PDCCH determined to use the TPC field for the original purpose PDCCH (e.g., a PDCCH with DAI ═ 1) according to a predefined rule.

Examples 4 to 3

Embodiment 4-3 relates to an example of applying the same ARI value in bundled CCs and subframes.

That is, when the above-described embodiments 4-1 and 4-2 are considered simultaneously (for example, when a plurality of CCs and a plurality of subframes become one bundling unit), if ARI values in the corresponding cells or the corresponding subframes are different, it may be ambiguous to calculate/select PUCCH resources. Therefore, ARI in PUCCH on PCell and SCell should be equally maintained, and at the same time, ARI in PDCCH in multiple subframes should be equally maintained.

Here, on the PCell, ARI values for PDCCHs (e.g., PDCCHs with DAI >1) other than a PDCCH (e.g., a PDCCH with DAI ═ 1) determined to use the TPC field for an original purpose according to a predefined rule may be equally maintained.

Fig. 33 is a diagram illustrating an embodiment of using a TPC field for an original purpose or ARI purpose according to a DAI value on a PCell.

The DAI field value is used as an accumulation counter of the PDCCH of each cell. That is, the DAI value is sequentially increased by 1 in each PUCCH of one cell. The PDCCH is not always present in all subframes.

In the illustrated example of fig. 33, on the PCell, there is a PDCCH for DL allocation in the first and third subframes. The DAI value is 0 in the PDCCH of the first subframe and is 1 in the PDCCH of the third subframe. On the SCell, DAI values are given in order in the PDCCH for DL allocation. In fig. 33, DAI values 0,1, 2, 3, … are illustrated, but these values have the same meaning as DAI values 1, 2, 3, 4, … from the UE's viewpoint.

In relation to the above-described embodiment 4, the TPC field in the PDCCH may be used for an original purpose or an ARI purpose according to the DAI value on the PCell. For example, a TPC field in a PDCCH in which a DAI value on the PCell is 0 (or 1 from the viewpoint of the UE), i.e., a TPC field in a PDCCH in the first subframe of the PCell in fig. 33 is used for an original purpose (i.e., power control), and a TPC field in another PDCCH on the PCell is reused for an ARI purpose.

The ARI values in the bundled subframes and/or the bundled cells may be equally maintained as in the above-described embodiments 4-1 to 4-3. For example, if the bundling window is applied on four subframes and five cells in the illustrated example of fig. 33, the UE may assume that the values of the TPC fields of the PDCCHs on the PCell and the SCell (i.e., the TPC fields for ARI purposes) are the same except for the TPC field in the first subframe of the PCell (where DAI is 0).

Example 5

Embodiment 5 relates to a method of using a TPC field for PUCCH resource allocation in a PCell-only reception case (i.e., a case of receiving only one or more PDSCHs for a PCell or a case of receiving only one or more PDCCHs on a PCell). Embodiment 5 is applied to partial ACK/NACK bundling. Partial bundling refers to bundling only in the time domain or in the CC domain (or frequency domain).

The DAI field is basically used for the original purpose (i.e., an accumulation counter for PDCCH on each cell) as in embodiment 4 above, and the TPC field in the PDCCH may be reused as ARI. In this case, the TPC field of the predetermined specific PDCCH is used for the original purpose. A specific PDCCH may be determined as a PDCCH of an nth subframe in the bundled subframes (this part has been described in embodiment 4 above, and thus, a repeated explanation is omitted). Alternatively, a PDCCH in which the TPC field is used for an original purpose may be determined based on the DAI value.

The above example of fig. 31 or 32 can be applied substantially identically to embodiment 5 as a basic operation, and the duplicate explanation that has been given in embodiment 4 above is omitted.

Hereinafter, a detailed method of using the TPC field for an original purpose or ARI purpose based on a DAI value when partial ACK/NACK bundling is applied will be described.

First, a TPC field in a PDCCH having an nth DAI value in a bundling subframe of a PCell may be defined for an original purpose. The value of the DAI field may be given as 0,1, 2, 3, … or may be given as 1, 2, 3, 4,.. from the UE's point of view.

In this case, in an ACK/NACK partial bundling mode (applied to time domain bundling or CC domain (or frequency domain) bundling), a DAI field may be included in one or more PDCCHs on the PCell. Here, the value of the DAI field included in one or more PDCCHs of the PCell should be determined based on a predetermined rule, and a detailed proposal thereof by the present invention will be described below.

When ACK/NACK partial bundling is applied, if a TPC field in a PDCCH of DAI ═ n is used for an original purpose (power control), a DAI field of one or more PDCCHs may be determined in various ways as follows.

In the legacy (LTE release 8) TDD mode, the DAI indicates an accumulated value of PDCCHs allocated to a UE, and if the DAI is simply applied to a multi-carrier environment, the DAI may be used as an accumulated value of PDCCHs allocated to the UE over all cells (or CCs). For example, as shown in fig. 34, when ACK/NACK bundling is applied in four subframes and on two CCs, the DAI value may be determined such that the DAI value increases in a direction in which the CC index increases in a bundling window. However, it is difficult to apply this scheme to partial bundling. Therefore, in the LTE release 10TDD mode in which a plurality of CCs (or cells) are configured, it is necessary to provide another method for determining a DAI value.

Fig. 35 is a diagram illustrating an example of determining a DAI value in a CA TDD system.

As an example, the DAI value may indicate the cumulative number of PDCCHs allocated to the UE in a plurality of subframes of each cell (fig. 35 (a)). Such a method for determining the DAI value is preferably used, for example, when bundling is applied in the time domain. The accumulated number of PDCCHs may be applied in a manner of counting PDCCHs in all subframes in one radio frame. Alternatively, the accumulated number of PDCCHs may be applied in a manner of counting PDCCHs in an actual bundling window (a unit for actually performing ACK/NACK bundling) in the time domain. In the example of fig. 35(a), DAI in PDCCHs in three subframes in an actual bundling window of a unit of four subframes on SCell #2 is determined as 0,1, and 2, and this is an example of using a DAI field as an accumulation counter for indicating that corresponding PUCCHs are a first PDCCH, a second PDCCH, and a third PDCCH, respectively.

As another example, the DAI value may indicate the total number of PDCCHs allocated to the UE on multiple CCs (or cells) per subframe (fig. 35 (b)). Such a DAI value determination method is preferably used, for example, when partial bundling is applied in the CC domain. The total number of PDCCHs may be determined as the number of PDCCHs in all CCs configured for the UE. Alternatively, the total number of PDCCHs may be determined as the number of PDCCHs in an actual bundling window (a unit for actually performing ACK/NACK bundling) in the CC region. In the example of fig. 35(b), the DAI value in the PDCCH in the first subframe is 2, and this is an example of using the DAI field as an indicator for indicating that the total number of PDCCHs in the corresponding subframe is 3.

Alternatively, the DAI value may be determined as an accumulation counter of PDCCHs allocated to the UE in a plurality of CCs (or cells) in each subframe. The cumulative number of PDCCHs may be counted for each PDCCH according to an ascending order of CC indexes (or cell indexes) in all CCs configured for the UE or according to an ascending order of CC indexes (or cell indexes) in an actual bundling window in the CC region. For example, in the example of fig. 35(b), the DAI value in the third subframe is determined as DAI-0 on PCell, 1 on

SCell #

2, 2 on

SCell #

3, and 3 on SCell # 4.

As shown in fig. 35(a), if DAI is used as an accumulation counter of PDCCHs allocated in an actual bundling window in the time domain (i.e., if a DAI value is reset on each CC), an embodiment of the present invention for ARI purpose using TPC fields of PDCCHs on a PCell and scells in addition to a PDCCH having a specific DAI value (e.g., DAI ═ 0) on the PCell may be equally applied.

Meanwhile, as shown in fig. 35(b), if DAI is used as the total number (or an accumulation counter) of PDCCHs allocated in an actual bundling window in a CC domain (or frequency domain), it may be difficult to apply an embodiment of the present invention for ARI purposes using TPC fields of PDCCHs on a PCell and a plurality of scells in addition to a PDCCH having a specific DAI value (e.g., DAI ═ 0) on the PCell.

For example, it may be assumed that a PDCCH is allocated to a specific UE in the first and second subframes and is not allocated on the SCell. Although this case corresponds to PCell-only reception, the DAI value of the PDCCH received by the UE is the same in both subframes (e.g., DAI ═ 0) (if the DAI field is used as an indicator or accumulation counter of the total number of PDCCHs in the corresponding subframe, the DAI value is 0 according to the above assumption). Then, it is ambiguous for the UE to determine which of the two PDCCHs on the PCell has its TPC field used for ARI purposes and which PDCCH has its TPC field used for the original purpose. In other words, if the DAI value is determined by a resetting scheme of the DAI value of each subframe, an embodiment of the present invention using TPC fields of PDCCHs on a PCell and a plurality of scells for ARI purposes, except for a PDCCH having a specific DAI value (e.g., DAI ═ 0) on the PCell, cannot be applied.

To solve the above problem, different DAI value determination methods may be applied on the PCell and the SCell. For example, on the SCell, the DAI may be used as an accumulation counter of PDCCHs allocated in an actual bundling window in a frequency domain (or CC domain), and on the PCell, the DAI may be used as an indicator (or accumulation counter) of a total number of PDCCHs allocated in the actual bundling window in a time domain.

Alternatively, in order to apply the present embodiment, it is necessary to define at least DAI on PCell as an accumulation counter of PDCCH in the time domain. Accordingly, the DAI of one or more PDCCHs on the PCell may be used as an accumulation counter of PDCCHs allocated in an actual bundling window in a time domain, and the DAI of one or more PDCCHs on the SCell may be used in the same or different manner as the DAI used on the PCell.

In an example of the present invention, which will be described below, it is assumed that the DAI field of the PDCCH is used as follows.

First, a DAI field in a PDCCH may be used as an accumulation counter of PDCCHs allocated in a plurality of subframes in a bundling view of each CC. That is, the DAI value is determined independently on each CC. Here, bit values 0,1, 2, and 3 of the DAI field indicate accumulation counts 1, 2, 3, and 4, respectively. That is, bit values expressed as 0,1, 2, and 3 from the viewpoint of the DAI field may also be expressed as 1, 2, 3, and 4 from the viewpoint of the DAI value interpreted by the UE.

Next, the DAI field of the PDCCH may also be used as an indicator of the total number of PDCCHs allocated on the plurality of CCs in the bundling window in each subframe. Bit values of 0,1, 2, and 3 of the DAI field may indicate a total number of 1, 2, 3, and 4, respectively. That is, bit values expressed as 0,1, 2, and 3 from the viewpoint of the DAI field may also be expressed as 1, 2, 3, and 4 from the viewpoint of the UE.

Fig. 36 to 39 illustrate various examples of DAI fields used in CC domain bundling. In the examples of fig. 36 to 39, 5 CCs configured for a UE and 4DL-1UL configuration in TDD are illustrated (i.e., ACK/NACK responses for DL transmission in four DL subframes are collected to transmit a response through PUCCH of one UL subframe). In addition, in the illustrated examples of fig. 36 to 39, the bundling window includes 5 CCs and four subframes. However, a case in which the maximum size of the actual bundling window is 4, 5, or 2 is illustrated in fig. 36 to 39.

Fig. 36 illustrates an example in which CC domain bundling is not applied on the PCell (the maximum size of an actual bundling window in the CC domain is 4). In this case, the DAI field of the PCell is used as an accumulation counter of PDCCHs allocated to subframes on the PCell. The DAI field of the SCell may be used as an indicator of the total number of PDCCHs allocated to the SCell, except for the PCell in each subframe.

Fig. 37 illustrates an example in which CC domain bundling is not applied on the PCell (the maximum size of the CC domain actual bundling window is 4). In this case, the DAI field of the PCell is used as an accumulation counter of PDCCHs allocated to subframes on the PCell. The DAI field of the SCell may be used as an indicator of the total number of PDCCHs allocated to the PCell and the SCell in each subframe. Therefore, according to the DAI of the SCell, the UE can know the total number of PDCCHs allocated by the BS in the corresponding subframe (i.e., the total number of PDCCHs on both the PCell and the SCell). The UE may use the DAI of the PCell and information on the total number of allocated PDCCHs to determine whether there is a PDCCH that the UE fails to detect/receive in the actual bundling window. Accordingly, CC domain ACK/NACK bundling in a corresponding subframe can be efficiently performed.

For example, in the illustrated example of fig. 37, if a DAI value in a PDCCH detected by the UE on an SCell in the second subframe is 2, the UE can recognize that the total number of PDCCHs allocated on the PCell and the plurality of scells is 3. Here, it may be assumed that the UE does not receive the PDCCH in SCell # 2. In this case, it cannot be determined whether a PDCCH that is not received is a PDCCH in an actual bundling window (i.e., on the SCell) or a PDCCH in a window other than the actual bundling window (i.e., on the PCell) only by a DAI value on the SCell. Since the DAI value on the PCell is given as an accumulated count in the time domain, the UE may confirm that the DAI values are sequentially provided in the first and third subframes on the PCell, and thus confirm that there is no PDCCH that the UE fails to detect on the PCell. As a result, the UE can know the case where PDCCH detection failed in one of the scells in the second subframe.

Fig. 38 illustrates an example in which CC domain bundling is applied regardless of PCell or SCell (the maximum size of a CC domain actual bundling window is 5). In this case, the DAI field of the PCell is used as an accumulation counter of PDCCHs allocated to subframes on the PCell. The DAI field of the SCell may be used to indicate the total number of PDCCHs allocated on both the PCell and the SCell in each subframe. Accordingly, the UE can know the total number of PDCCHs allocated by the BS in the subframe (the total number of PDCCHs in both the PCell and the SCell) through the DAI of the SCell. Because the DAI value indicates the number of PDCCHs in the actual bundling window, the UE may determine whether there are PDCCHs that the UE fails to detect/receive in the actual bundling window. Accordingly, CC domain ACK/NACK bundling in a corresponding subframe can be efficiently performed.

Fig. 39 illustrates a case in which the maximum size of the CC field actual bundling window is 2. At this time, CC domain bundling is not applied on the PCell, and two actual bundling windows having a maximum size of 2 may be configured on four scells. The DAI field of the PCell is used as an accumulation counter of PDCCHs allocated to subframes on the PCell. The DAI field of the SCell may be used as an indicator of the total number of PDCCHs allocated on the SCell (up to two scells) in the actual bundling window, except for the PCell in each subframe.

ACK/NACK partial bundling (bundling in the time or frequency domain) is applied to embodiment 5, and even in this case, when ARI (═ TPC field) values in a bundling window are different, an ACK/NACK bundling operation may not be clear.

Accordingly, in the PCell-only reception case, the ARI value of a PDCCH in which the TPC field on the PCell is reused for ARI purpose (i.e., except for a PDCCH in which TPC is used for original purpose) in the bundled subframe can be equally maintained. In addition, on a bundled CC, the value of a field for ARI purpose (═ TPC field) on the PCell can be maintained equal to the value of a field for ARI purpose (═ TPC field) on the SCell. Also, on the bundled CC and the subframe, ARI values of PDCCHs (e.g., PDCCHs with DAI >1) other than a PDCCH determined to use the TPC field for an original purpose according to a predefined rule (e.g., a PDCCH with DAI ═ 1) can be equally maintained on the PCell. In connection with this, the principle of the present invention described in embodiments 4-1 to 4-3 above can be applied to embodiment 5 in the same manner. For clarity, the description of the overlapping parts is omitted.

UL ACK/NACK transmission for DL SRS transmission in multi-carrier support systems

LTE release 8 systems support SPS. If DL SPS transmission is activated, time/frequency resources for SPS transmission may be pre-allocated through the PDCCH, and a PDSCH without a corresponding PDCCH may be transmitted through the allocated resources.

The ACK/NACK feedback related to SPS can be divided into two types. One type is to transmit ACK/NACK feedback in subframe n for' PDCCH indicating DL SPS release detected by the UE in one or more n-k. Another type is to transmit ACK/NACK feedback in subframe n for 'PDSCH transmission without corresponding PDCCH in one or more subframes n-k'. The first type corresponds to the following case: wherein if there is a PDCCH in the n-k subframe (where k may be one or more values), ACK/NACK feedback for the PDCCH is transmitted in the n subframe. The second type corresponds to the following case: wherein if an SRS transmission is received in an n-k subframe without additional PDCCH after SPS activation, ACK/NACK feedback for the corresponding SPS transmission is regularly transmitted in the n subframe. For a detailed description related to SPS transmissions, reference may be made to document 3GPP TS 36.213.

A PUCCH resource index for ACK/NACK feedback in LTE rel-8 system is basically determined based on a CCE index of PDCCH. If the ACK/NACK response in one PUCCH in the nth subframe includes an ACK/NACK response for one or more PDCCHs (including a general PDCCH and a PDCCH indicating DL SPS release) in the nth-k subframe, a PUCCH resource index may be derived from a CCE index of the PDCCH. However, if only an ACK/NACK response should be transmitted for an SPS without a PDCCH in the n-k subframe, a PUCCH resource index for the ACK/NACK response cannot be determined. To solve such a problem, in the LTE release 8 system, a PUCCH resource index set (for example, one set composed of four PUCCH resource indexes) for a case where only 'PDSCH transmission without a corresponding PDCCH' (i.e., SPS PDSCH transmission) exists is indicated in advance by RRC signaling. Also, whether to use one PUCCH resource of the PUCCH resource index set is determined by a TPC field in the PDCCH indicating SPS activation. PUCCH resource index for DL SPS is defined in table 14 shown below

And the value of the TPC field.

[ Table 14]

If the above-described DL SPS transmission is performed in the multi-carrier support system, an ACK/NACK transmission method considering the DL SPS transmission must be provided.

Various embodiments of the invention are described herein on the following premises: similar to

embodiments

4 and 5 described above, the TPC field of the first PDCCH (PDCCH with DAI ═ 1(DAI ═ 1, 2, 3, 4, …)) for the PCell of a specific UE is used for power control purposes for the original purpose, and the TPC field of the other PDCCH or PDCCHs is used for ARI purposes. It is to be noted that such assumption is for clarity of explanation, and application examples of the present invention are not limited thereto. That is, the ARI information may be provided through other methods.

When an ACK/NACK response for 'PDSCH transmission without corresponding PDCCH' (hereinafter referred to as 'SPS without PDCCH') in the n-k subframe is transmitted in the n-k subframe, SPS without PDCCH may be received in the n-k subframe and, in addition, one PDCCH may be detected. Then, an ACK/NACK response for PDCCH and an ACK/NACK response for SPS without PDCCH need to be transmitted. Here, if one detected PDCCH is the first PDCCH (e.g., a PDCCH with DAI ═ 1), since the TPC field of the PDCCH is used for the original purpose, this case is when the UE does not receive ARI information. Therefore, the UE cannot determine a resource index for PUCCH format 3. Hereinafter, various embodiments of the present invention for solving the above problems will be described.

In the following description, ACK/NACK transmission is required in one of the following three cases. In summary, case 1 is ACK/NACK for 'PDSCH with PDCCH', case 2 is ACK/NACK for 'DL SPS release PDCCH', and case 3 is ACK/NACK for 'DL SPS PDSCH'.

Case 3 may be referred to as 'PDSCH without corresponding PDCCH', ACK/NACK for 'SPS without PDCCH', or simply ACK/NACK for 'SPS'. In case 1, a PDCCH of 'PDSCH with PDCCH' may be referred to as 'PDCCH corresponding to PDSCH'.

Example 6

Embodiment 6 relates to a method for transmitting an ACK/NACK response always using PUCCH format 3.

The PUCCH format 3 resource index set for SPS only may be indicated to the UE through RRC signaling. For example, the UE may be provided with information regarding the UE to be controlled in the form shown in table 13 above

And

information of the constructed set. In addition, which resource index of the PUCCH format 3 resource index set is to be used may be specified by a TPC field in the PUCCH for indicating SPS activation.

As an example, when ACK/NACK feedback is required only for SPS without PDCCH, a specific PUCCH format 3 resource index indicated by the SPS activation PDCCH in the set of RRC configurations may be selected and used. That is, ACK/NACK for only SPS without PDCCH may be transmitted using PUCCH format 3.

As another example, the following method may be applied to a case in which ACK/NACK feedback for 'SPS without PDCCH' and 'one PDSCH with PDCCH' is required.

The first method is to select and use a PUCCH format 3 resource index indicated by the SPS activation PDCCH. That is, the ACK/NACK responses for 'SPS without PDCCH' and 'one PDSCH with PDCCH' may also be transmitted using PUCCH format 3.

The second method is further divided into two methods according to whether ARI information is included in one 'PDCCH corresponding to PDSCH'.

When one 'PDCCH corresponding to a PDSCH' is a PDCCH that does not include ARI information (e.g., a PDCCH in which a first DAI (DAI ═ 1)), a PUCCH format 3 resource index indicated by the SPS activation PDCCH may be selected and used. That is, even if ARI information is not acquired from 'PDCCH corresponding to PDSCH', ACK/NACK responses for 'SPS without PDCCH' and 'one PDSCH with PDCCH' can be transmitted using PUCCH format 3.

If one 'PDCCH corresponding to PDSCH' is a PDCCH including ARI information (e.g., a PDCCH without the first DAI (DAI > 1)) (which may be the case when the UE loses the PDCCH with the first DAI), a PUCCH format 3 resource index using an ARI value indicated by a TPC field in the 'PDCCH corresponding to PDSCH' may be selected and used.

Meanwhile, when a plurality of ACK/NACK feedbacks including ACK/NACK for 'SPS without PDCCH' are transmitted, a PUCCH format 3 resource index may be determined by an ARI value indicated by a TPC field of a second or more PDCCHs on the PCell (e.g., one or more PDCCHs where DAI >1) or one or more PDCCHs on one or more scells.

Example 7

Embodiment 7 relates to a method for operating ACK/NACK for transmission of SPS 'only' without PDCCH always in fallback mode. Here, the fallback mode refers to ACK/NACK transmission according to the operation defined in LTE release 8, for example, ACK/NACK transmission using PUCCH format 1a/1 b. On the other hand, with regard to ACK/NACK transmission for 'SPS without PDCCH' and other DL transmissions (PDSCH with PDCCH), PUCCH format 3 may be used.

To this end, a PUCCH format 1a/1b resource index set to be used for transmitting 'SPS only' may be indicated to the UE through RRC signaling. The PUCCH format 1a/1b resource index set may be configured as shown in table 14 or may be configured according to other schemes. When SPS activation is indicated, which index of the PUCCH resource index set is to be used may be specified by a TPC field in the SPS activation PDCCH.

Since time/frequency resources for SPS transmission are preset between the BS and the UE, the BS and the UE know when to transmit and receive ACK/NACK feedback for 'SPS without PDCCH'. Accordingly, in a bundling window including SPS for a specific UE, the BS may use TPC fields of all PDCCHs for ARI purposes without distinguishing between PUCCHs on the PCell, respectively. That is, during transmission of ACK/NACK feedback only for SPS without PDCCH, one or more PDCCHs transmitted in a bundling window including SPS without PDCCH may use all TPC fields for ARI purposes without distinguishing between PCell and scells.

In this case, with respect to PUCCH transmission of ACK/NACK feedback for SPS without PDCCH, the TPC field of PDCCH is not used for the original purpose (UL transmit power control). However, the TPC value in the PDCCH is a relative offset value to the previous transmission power, not an absolute value, and maintains the preset transmission power even if the UE does not update the TPC value once or twice. In addition to a transmit power control method using a TPC field in a PDCCH, a supplementary power control method is provided. Also, when transmission of SPS without PDCCH is required in FDD mode, it is defined that the UE cannot obtain the TPC value for the original purpose. Therefore, the operation described in the above example of the present invention in TDD does not significantly affect network performance even when the TPC of the original purpose is not applied.

According to the example of embodiment 7, when ACK/NACK feedback is required only for SPS without PDCCH, a specific PUCCH format 1a/1b resource index indicated by SPS activation PDCCH of the RRC-configured set may be selected and used. That is, for ACK/NACK only for SPS without PDCCH, fallback mode operation using PUCCH format 1a/1b may be performed.

As another example, when ACK/NACK feedback for 'SPS without PDCCH' and 'one PDSCH with PDCCH' is required, since the TPC fields of all PDCCHs in the bundling window are used for ARI purpose as described above, PUCCH formatting 3 resource indexes may be selected and used according to ARI values indicated by the TPC field of one detected PDCCH.

Meanwhile, when a plurality of ACK/NACK feedbacks including ACK/NACK for SPS without PDCCH are transmitted, since the TPC fields of all PDCCHs in the bundling window are used for ARI purposes as described above, the PUCCH format 3 resource index may be determined by one or more ARI values indicated by the TPC fields of one or more PDCCHs on the PCell and/or SCell.

Example 8

Embodiment 8 relates to a method for always performing ACK/NACK for DL transmission comprising 'SPS transmission without PDCCH' in fallback mode.

To this end, a PUCCH format 1a/1b resource index set to be used for transmission of SPS "only" without PDCCH may be indicated to the UE through RRC signaling. The PUCCH format 1a/1b resource index set may be configured as shown in table 14 or may be configured according to other schemes. When SPS activation is indicated, which index of the PUCCH resource index set is to be used may be specified by a TPC field in the SPS activation PDCCH.

According to the example of embodiment 8, when ACK/NACK feedback for SPS without PDCCH 'only' is required, a specific PUCCH format 1a/1b resource index indicated by the SPS activation PDCCH of the RRC-configured set may be selected and used. That is, for ACK/NACK of SPS without PDCCH only, a fallback mode using PUCCH format 1a/1b may be performed. Here, ACK/NACK feedback for SPS without PDCCH may have a size of 1 or 2 bits according to the number of codewords, and PUCCH format 1a or 1b may be used.

As another example, ACK/NACK feedback for 'SPS without PDCCH' and 'one PDSCH with PDCCH' is required, a specific PUCCH format 1a/1b resource index indicated by the SPS activation PDCCH of the RRC-configured set may be selected and used. That is, even for ACK/NACK feedback for transmissions including SPS without PDCCH, a fallback mode using PUCCH format 1a/1b may be performed. Here, a 2-4 bit feedback payload is required according to the number of codewords for each of 'SPS without PDCCH' and 'one PDSCH with PDCCH' (this is because 1-bit ACK/NACK response bits are generated with respect to one codeword when spatial bundling is not applied).

Hereinafter, a detailed example of the present invention when ACK/NACK feedback for 'SPS without PDCCH' and 'one PDSCH with PDCCH' is required will be described.

Example 8-1

Embodiment 8-1 relates to a method of using a channel selection scheme of M-2, 3 or 4 when ACK/NACK feedback is required for 'SPS without PDCCH' and 'one PDSCH with PDCCH'. That is, the size of the ACK/NACK feedback payload for 'SPS without PDCCH' and 'one PDSCH with PDCCH' is 2 to 4 bits, and in order to transmit the ACK/NACK feedback without any loss, a channel selection scheme using 2, 3, or 4 PUCCH formats 1b (or PUCCH format 1a) may be applied. When the channel selection scheme for PUCCH format 1b (or 1a) defined in LTE release 8 is used, this may be expressed as operating in a fallback mode using the channel selection scheme of LTE release 8.

Among the plurality of resources for channel selection, one PUCCH format 1b (or 1a) resource is derived from a CCE index of 'PDCCH corresponding to PDSCH', and another PUCCH format 1b (or 1a) may be indicated by a PDCCH for indicating SPS activation. The ACK/NACK information may be transmitted through a channel selection scheme that selects one of two PUCCH format 1b (or 1a) resources.

In addition, if PUCCH resources are further required (e.g., M ═ 3 or 4), PUCCH resources corresponding to a value (CCE index + offset) obtained by adding a prescribed offset (e.g., 1) to the CCE index of "PDCCH corresponding to PDSCH" may be used for channel selection. Instead of or in addition to additional resources based on the CCE index of 'PDCCH corresponding to PDSCH', PUCCH resources corresponding to a value obtained by adding a resource index assigned through SPS activation PDCCH to a prescribed offset (e.g., 1) may be used for channel selection.

Alternatively, similar to the above scheme, a channel selection scheme using PUCCH format 1a/1b resource indexes determined explicitly or implicitly from information related to 'SPS without PDCCH' and 'one PDSCH with PDCCH' may be applied.

When the UE determines a PUCCH resource for transmitting ACK/NACK information according to embodiment 8-1, the BS may attempt to receive ACK/NACK information for three cases of a PUCCH format 3 region, a PUCCH format 1a/1b region, and a channel selection (PUCCH format 1b (or 1a)) region.

Since the UE can transmit ACK/NACK information using any one of the three cases, the BS should perform blind decoding in the above three cases.

Example 8 to 2

Embodiment 8-2 relates to a method of using a fallback mode using PUCCH format 1b (or 1a) defined in LTE release 8 using spatial bundling (i.e., ACK/NACK bundling for multiple codewords) when ACK/NACK feedback is required for 'SPS without PDCCH' and 'one PDSCH with PDCCH'.

First, when 'SPS without PDCCH' corresponds to transmission of a plurality of (e.g., 2) codewords, spatial bundling is performed for ACK/NACK responses thereto. Similarly, when 'one PDSCH with PDCCH' corresponds to transmission of a plurality of (e.g., 2) codewords, spatial bundling is performed for ACK/NACK responses thereto. If only one of 'SPS without PDCCH' and 'PDSCH with PDCCH' is one codeword transmission and the other is two codeword transmission, spatial bundling is performed only with respect to the two codeword transmission.

Therefore, the size of the ACK/NACK payload for 'SPS without PDCCH' and 'one PDSCH with PDCCH' is reduced to 2 bits when spatial bundling is performed, compared to 2 or 4 bits when spatial bundling is not performed.

The 2-bit ACK/NACK feedback may be transmitted through the legacy LTE release 8 PUCCH format 1b (or 1 a). That is, if spatial bundling is performed, the ACK/NACK feedback may be operated in a fallback mode using PUCCH format 1b (or 1a) of LTE release 8.

In this case, PUCCH format 1a/1b resource indexes derived from a CCE index of one 'PUCCH corresponding to PDSCH' may be selected and used. Alternatively, PUCCH format 1a/1b resource index indicated by the SPS activation PDCCH in the RRC-configured resource index set may be selected and used. In other words, the corresponding ACK/NACK responses fall back to PUCCH format 1a and are multiplexed by phase rotation, i.e., one of the two ACK/NACK responses is mapped to the I channel and the other is mapped to the Q channel. Alternatively, the two ACK/NACK responses fall back to PUCCH format 1b and are multiplexed.

For example, of two-bit ACK/NACKs used in PUCCH format 1b used in LTE release 8, the Most Significant Bit (MSB) may be mapped to ACK/NACK for ' SPS without PDCCH ', and the Least Significant Bit (LSB) may be mapped to ACK/NACK for ' one PDSCH with PDCCH (e.g., PDCCH with DAI ═ 1). Alternatively, multiple ACK/NACKs may be mapped in a reverse manner to the above example.

As another embodiment, ACK/NACK for ' SPS without PDCCH ' is mapped to I-axis of QPSK constellation, and ACK/NACK for ' one PDSCH with PDCCH (e.g., PDCCH with DAI-1) may be mapped to Q-axis of QPSK constellation. Alternatively, multiple ACK/NACKs may be mapped in a manner opposite to the above example. In addition, according to the received timing, ACK/NACK for 'SPS without PDCCH' and 'one PDSCH with PDCCH' received first is mapped to I-axis, and ACK/NACK for subsequent reception may be mapped to Q-axis. Alternatively, multiple ACK/NACKs may be mapped in a manner opposite to the above example.

For example, when ACK/NACK for ' SPS without PDCCH ' is mapped to I-axis and ' one PDSCH with PDCCH (e.g., PDCCH with DAI ═ 1) is mapped to Q-axis, even if the UE fails to detect PDCCH (i.e., ' PDCCH corresponding to PDSCH '), the BS may receive ACK/NACK response for at least SPS. This is because, when the UE fails to detect the PDCCH, the constellation position when ACK/NACK for ' SPS without PDCCH ' is mapped to segment number I-axis is equal to the constellation position when ACK/NACK for ' only ' SPS without PDCCH ' is transmitted using BPSK constellation (i.e., I-axis) using PUCCH format 1 a.

As another example, '1, 1' and '0, 0' of the QPSK constellation may be mapped to ACK/NACK for 'SPS without PDCCH', and '0, 1' and '1, 0' may be mapped to one PDSCH 'ACK/NACK for' PDCCH with PDCCH (e.g., PDCCH with DAI ═ 1). Alternatively, the corresponding plurality of ACK/NACKs may be mapped in a reverse manner to the above example.

The above constellation mapping may be equally applied to the case where the transmission mode in each cell is a MIMO mode and other cases. The above constellation mapping may also be applied regardless of whether spatial bundling is actually applied (i.e., regardless of whether there is a 2-codeword transmission).

In application embodiment 8-2, spatial bundling may even be applied to ACK/NACK feedback for SPS 'only' without PDCCH. In this case, the BS should perform blind decoding for the following three cases: a PUCCH format 1a/1b region for ACK/NACK for 'SPS only', a PUCCH format 1a/1b region for ACK/NACK for 'SPS without PDCCH' and 'one PDSCH with PDCCH', and a PUCCH format 3 region.

In addition, in application embodiment 8-2, instead of a resource index derived from a CCE index of 'PDCCH corresponding to PDSCH' as a PUCCH resource, a PUCCH resource index designated by an SPS activation PDCCH of a PUCCH resource set configured by RRC may be used, and other parts may be equally applied.

Examples 8 to 3

Embodiment 8-3 relates to a method of applying spatial bundling (i.e., ACK/NACK bundling for multiple codewords) and using a channel selection scheme of M-2 when ACK/NACK feedback for 'SPS without PDCCH' and 'one PDSCH with PDCCH' is required. When the channel selection scheme for PUCCH format 1b (or 1a) defined in LTE release 8 is used, this may be expressed as a fallback mode operation using the channel selection scheme of LTE release 8.

First, in case of transmission of a plurality of (e.g., two) codewords for 'SPS without PDCCH', spatial bundling is performed for ACK/NACK responses thereto. Similarly, in case of transmission of a plurality of (e.g., two) codewords for 'one PDSCH with PDCCH', spatial bundling is performed for ACK/NACK responses thereto. If one of 'SPS without PDCCH' and 'PDSCH with PDCCH' is one codeword and the other is two codewords, spatial bundling is performed only for transmission of the two codewords.

Accordingly, the size of the ACK/NACK payload for 'SPS without PDCCH' and 'one PDSCH with PDCCH' is reduced from 2 or 4 bits when spatial bundling is not performed to 2 bits when spatial bundling is performed.

The 2-bit ACK/NACK feedback may be transmitted through PUCCH format 1b (or 1a) of legacy LTE release 8. Here, a channel selection scheme using M ═ 2 of PUCCH1b (/1a) may be used. That is, 2-bit ACK/NACK feedback as a result of performing spatial bundling may be transmitted using a fallback mode of PUCCH format 1b (1 a).

Here, M ═ 2 may indicate transmission of two kinds of ACK/NACK information (2-bit ACK/NACK information) as a result of spatial bundling, or may indicate channel selection using two PUCCH resources. Accordingly, the detection performance of the BS can be improved by using channel selection.

Among the two PUCCH resources for channel selection, the first PUCCH resource may use a PUCCH format 1a/1b resource index designated by the SPS activation PDCCH, and the second PUCCH resource may use a PUCCH format 1a/1b resource index derived from a CCE index of 'PDCCH corresponding to PDSCH'. In contrast to the above example, the first and second PUCCH resources may be mapped to a PUCCH resource index designated by the SPS activation PDCCH and a PUCCH resource index derived from a CCE index of 'PDCCH corresponding to PDSCH', respectively. The ACK/NACK information can be transmitted through a channel selection scheme that selects one of two PUCCH format 1b (or 1a) resources.

In the present embodiment, the channel selection mapping relationship between ACK/NACK information and PUCCH resources may be configured as shown, for example, in table 5 or table 8. However, this is merely exemplary, and a new channel selection mapping relationship may be defined and used.

As an example of this embodiment, it is assumed that a channel mapping relationship using PUCCH format 1b is given as shown in table 5. In two PUCCH resources for channel mapping (f:)

And) In the method, a PUCCH resource designated by the SPS activation PDCCH may be mapped to

And, PUCCH resources derived from CCE index of 'PDCCH corresponding to PDSCH' may be mapped toSuch a mapping configuration may be determined regardless of a reception order (reception time) of 'SPS without PDCCH' and 'PDSCH corresponding to PDCCH'. For example, even when a particular UE transmits a response after losing PDCCH (i.e., 'PDCCH corresponding to PDSCH') and receiving only SPS, the UE may receive an ACK/NACK response at least for that SPS. This is because, when the UE fails to detect the PDCCH, PUCCH resources for ACK/NACK transmission for' SPS without PDCCH

PUCCH resources related to ACK/NACK transmission for SPS 'only' without PDCCH

The same is true. Meanwhile, as a modified example of this embodiment, the corresponding PUCCH resource and DL transmission type (PUCCH or SPS) may be mapped inversely to the above example or may be mapped according to the order of reception times.

As another example of the present embodiment, in the channel mapping relationship using the PUCCH format 1b, ACK/NACK for SPS may be mapped to MSB of 2-bit ACK/NACK (i.e., ACK/NACK for SPS is mapped to a first bit), and ACK/NACK for 'one PDSCH having PDCCH (e.g., PDCCH having DAI ═ 1') may be mapped to LSB (i.e., ACK/NACK for PDSCH having PDCCH is mapped to a second bit). Alternatively, even if the UE fails to detect a PDCCH (i.e., ' PDCCH corresponding to PDSCH ') when ACK/NACK for SPS is mapped to I-axis and ACK/NACK for ' one PDSCH having PDCCH (e.g., PDCCH having DAI-1) is mapped to Q-axis, the BS may receive ACK/NACK responses for at least SPS transmissions. This is because the constellation position when ACK/NACK for 'SPS without PDCCH' is mapped to I-axis in case of PUCCH detection failure is the same as the constellation position when the UE transmits ACK/NACK response for 'SPS without PDCCH only' using a PUCCH format 1a using BPSK constellation (i.e., I-axis). Alternatively, a mapping relationship reverse to the above example may be configured, and the mapping may be performed according to the order of the received times.

To ensure that the BS receives ACK/NACK responses at least for SPS, specific information can be mapped to specific PUCCH resources in various ACK/NACK feedback transmission scenarios. For example, the channel selection mapping relationship may be configured such that the PUCCH resources to which ACK/NACK for SPS transmissions is mapped are the same as the PUCCH resources on which ACK/NACK for 'SPS only' transmissions are transmitted.

Table 15 below shows modulation symbols (or constellations) for PUCCH formats 1a and 1b in legacy LTE release 8/9.

[ Table 15]

In table 15, it is assumed that the value '0' of b (0) is NACK and '1' is ACK. Then, the value '00' of b (0), b (1) represents ACK/ACK, and '11' represents NACK/NACK. In this case, at least one previous bit b (0) has the same modulation symbol as in the PUCCH formats 1a and 1 b. In other words, b (0) is always 0 in both the two PUCCH formats 1a and 1b when d (0) ═ 1, and is always 1 in both the two PUCCH formats 1a and 1b when d (0) ═ 1. Accordingly, the BS may receive and detect information on at least one previous bit b (0), even if the BS does not know whether to transmit the received ACK/NACK feedback using PUCCH format 1a or PUCCH format 1 b. The channel selection mapping relationship may be configured such that ACK/NACK for 'SPS without PDCCH' uses a PUCCH resource mapped to one previous bit b (0). Therefore, the BS can guarantee reception of ACK/NACK at least for SPS.

For example, when M is 2, the channel selection mapping relationship shown in table 16 below may be used.

[ Table 16]

In table 16, ACK/NACK for SPS is mapped to HARQ-ACK (0), and ACK/NACK for 'PDSCH with PDCCH' may be mapped to HARQ-ACK (1).

For example, assume that only SPS with one codeword is received and 'PDSCH with PDCCH' is not received. In this case, an ACK/NACK response for SPS may be transmitted using PUCCH format 1 a.

Meanwhile, when 'PDSCH with PDCCH' is received together with SPS, channel selection according to the present invention may be used. In this case, PUCCH resources indicated by the SPS activation PDCCH in the PUCCH resource set configured by the higher layer for SPS may be used as those of table 16

In addition, PUCCH resources derived from 'CCE index of PDCCH corresponding to PDSCH' (implicitly by a predetermined rule) may be used as table 16In this case, the BS should be able to receive an ACK/NACK response for SPS regardless of whether the UE loses 'PDCCH corresponding to PDSCH'.

As described above, if the UE transmits an ACK/NACK response for the SPS, then use

Here, ACK corresponds to a modulation symbol in which b (0) ═ 1 and d (0) ═ 1, and NACK corresponds to a modulation symbol in which b (0) ═ 0 and d (0) ═ 1. Meanwhile, when the UE transmits an ACK/NACK response for the SPS and 'PDSCH with PDCCH', the resource on which the ACK/NACK response for the SPS is transmitted may be confirmed in table 16. Now, the description will be given of the case of using in Table 16

Case of 'ACK, NACK/DTX' and 'NACK, NACK/DTX'. The 'ACK, NACK/DTX' corresponds to a modulation symbol in which b (0) b (1) is 11 and d (0) is 1, and the 'NACK, NACK/DTX' corresponds to a modulation symbol in which b (0) b (1) is 00 and d (0) is 1. In summary, in the transmission of ACK/NACK response only for SPS and ACK/NACK response for SPS and' PDSCH with PDCCHIn both, transmission using the same modulation symbol (i.e., d (0) ═ 1 for ACK and d (0) ═ 1 for NACK) is transmitted

ACK/NACK response to SPS in the ACK/NACK transmission of (a). Therefore, the BS can detect that

The above signal timing acknowledges the ACK/NACK response at least for the SPS regardless of whether the BS has received the ACK/NACK response for the SPS or the ACK/NACK response for the SPS and 'PDSCH with PDCCH'.

Meanwhile, in the case of 'ACK, ACK' and the case of 'NACK/DTX, ACK' in table 16, resources derived from the CCE index of 'PDCCH corresponding to PDSCH', that is, using resources derived from the CCE index of 'PDCCH' may be used

To transmit an ACK/NACK response. Is received at

Above, the BS may confirm reception of ACK/NACK responses for 'SPS without PDCCH' and 'PDSCH with PDCCH'.

In the above example, although the PUCCH format 1a has been described for convenience, the same principle of the present invention may be applied to the PUCCH format 1 b.

For example, the ACK/NACK response for SPS with two codewords 'only' may be transmitted using PUCCH format 1 b. Meanwhile, when 'PDSCH with PDCCH' is received together with SPS, spatial bundling may be used according to an example according to the present invention. In the above two cases, ACK/NACK information for SPS is transmitted through the same channel (PUCCH resource) and modulation symbol. More specifically, ACK/ACK, ACK/NACK, NACK/ACK, and NACK/NACK for two codewords of SPS become ACK, NACK, and NACK by applying spatial bundling (e.g., logical product). If ACK/NACK responses for SPS and 'PDSCH with PDCCH' are transmitted simultaneously,the ACK/NACK response to the SPS becomes ACK or NACK according to the spatial bundling result and the response is the same as ACK/NACK and NACK/NACK, respectively, of the channel and modulation symbol used for the ACK/NACK response to only the SP. Thus, when a signal is detected

In this case, the BS may confirm the ACK/NACK response as the spatial bundling result according to whether or not a previous signal (e.g., b (0)) for at least the SPS is ACK or NACK, regardless of whether or not the BS has received the ACK/NACK response for the SPS or the ACK/NACK response for the SPS and 'PDSCH with PDCCH'.

The above constellation mapping may be equally applied to the case where the transmission mode in each cell is a MIMO mode and other cases. Constellation mapping may also be applied regardless of whether spatial bundling is actually applied (i.e., regardless of whether there is a 2-codeword transmission).

In application embodiment 8-3, spatial bundling may even be applied to ACK/NACK feedback transmission 'only' for SPS without PDCCH. This case can reduce the number of areas in which blind detection should be performed by the BS, as compared with embodiment 8-1 or 8-2. More specifically, among the channel selection schemes defined in LTE release 8, a channel selection scheme for a large value of M is composed of a superset of channel selection schemes for a small value of M. For example, one previous bit (e.g., b (0)) or transmission of only ACK/NACK in the channel selection of M ═ 2 has the same result as transmission of 1-bit ACK/NACK using PUCCH format 1a without applying channel selection. Accordingly, when a PUCCH format 1a/1b resource index indicated by an SPS activation PDCCH for ACK/NACK for 'SPS only' is used as a first resource index for channel selection, it is possible to distinguish between a case in which channel selection is used and a case in which channel selection is not used. In this case, ACK/NACK responses to 'SPS without PDCCH' and 'PDSCH with PDCCH' are detected, and 'only' ACK/NACK responses to SPS are automatically detected. Therefore, the BS can perform blind detection in two regions for ACK/NACK detection on PUCCH format 1a/1b resources for channel selection (including ACK/NACK detection for SPS only' and for ACK/NACK detection on PUCCH format 3).

Hereinafter, a detailed application example of embodiment 8-3 will be described.

Example 8-3-1

As described above, the ACK/NACK response is generated with respect to three cases. Case 1 relates to a PDSCH with a corresponding PDCCH, case 2 relates to a PDCCH for indicating DL SPS release, and case 3 relates to a PDSCH without a corresponding PDCCH. Case 3 is also referred to as ACK/NACK for SPS PDSCH.

In the description of the present embodiment, for the 'PDCCH' indicating case 1 or case 2 and the 'SPSPDSCH' indicating case 3 of the ACK/NACK response, an operation is described in which a specific UE performs DL reception for the above three cases and performs ACK/NACK for DL reception. The ACK/NACK response transmitted in the nth UL subframe has a relationship with the ACK/NACK response for DL transmission in the nth-K subframe for the above three cases (where K ∈ K, and K: { K: } K ∈ K₀,k₁,…k_M-1And refer to table 12). The description of the ACK/NACK transmission subframe position will be omitted below.

In this embodiment, in order to support dynamic transmit power caused by TPC commands without reducing performance, a predefined channel selection scheme (defined in LTE release 8 or release 10) over PUCCH format 1a may be used.

A case in which one serving cell is configured will now be described first.

In this case, the use of the TPC field is determined as follows.

A 2-bit TPC field in a PDCCH in which DL DAI is 1 is used for a TPC command for an original purpose.

The 2-bit TPC field in the PDCCH in DL DAI >1 is used for ARI purposes. The UE assumes that the ARI value is the same in all PDCCHs in which DL DAI > 1.

In addition, the use of the PUCCH format is determined as follows.

If the UE receives only SPS PDSCH, then LTE release 8 PUCCH format 1a/1b resources are used (i.e., operation in fallback mode).

If the UE receives one PDCCH in which DL DAI is 1, LTE release 8 PUCCH format 1a/1b resources are used (i.e., operation in fallback mode).

If the UE receives the SPS PDSCH and another PDCCH with DL DAI ═ 1, a predefined channel selection scheme (the channel selection schemes defined in LTE release 8 and release 10) over PUCCH format 1a is used. Here, the first PUCCH resource is determined by higher layer configuration (e.g., by a resource indicated by an ARI of an SPS PDCCH in an RRC-configured resource set), and the second PUCCH resource is determined based on a number (or index) of a first CCE used for transmission of a corresponding PDCCH (i.e., a PDCCH in which DL DAI ═ 1).

In other cases, PUCCH format 3 is used as the configured PUCCH format.

Meanwhile, a case in which a plurality of serving cells are configured will now be described.

Here, the use of the TPC field is determined as follows.

A 2-bit TPC field in a PDCCH in which DL DAI ═ 1 on PCell only is used for the TPC command of the original purpose.

The 2-bit TPC field of all other one or more PDCCHs on the PCell and one or more scells is used for the original purpose TPC command. The UE assumes that the ARI values are the same in all one or more PDCCHs on the PCell and one or more scells.

In addition, the use of the PUCCH format is determined as follows.

If the UE receives only the SPS PDSCH and another PDCCH where DL DAI is 1 on the PCell, a predefined channel selection scheme (a channel selection scheme defined in LTE release 8 or release 10) through PUCCH format 1a is used. Here, the first PUCCH resource is determined by higher layer configuration, for example, by a resource indicated by ARI of the SPS activation PDCCH in the RRC-configured resource set (see table 14), and the second PUCCH resource is determined based on the number (or index) of the first CCE used for transmission of the corresponding PDCCH, i.e., the PDCCH in which DL DAI is 1.

In other cases, PUCCH format 3 is used as the configured PUCCH format.

Example 8-3-2

In the description of the present embodiment, 'PDCCH' related to ACK/NACK response indicates case 1 or case 2, and 'SPS PDSCH' indicates case 3, as described in embodiment 8-3-1 above. The term 'PDSCH with DAI ═ 1' or 'PDSCH with DL DAI > 1' means that DL DAI indicated by PDCCH corresponding to PDSCH is 1 or more than 1. The description of the ACK/NACK transmission subframe position will be omitted below.

If the UE receives the SPS PDSCH and the PDCCH with DL DAI ═ 1, the UE cannot know the available PUCCH resources because there is no ARI information. To solve this problem, the following method may be considered.

A case in which channel selection of M-2 in LTE release 8 is used will now be described first.

If the UE receives only SPS PDSCH and PDSCH with DL DAI ═ 1 and does not receive PDSCH with DL DAI >1, the UE transmits ACK/NACK through TDD channel selection of M ═ 2 in LTE release 8 while applying spatial bundling for the PDSCH. When using LTE release 8 TDD channel selection, the UE transmits two ACK/NACK bits. Here, one of the channel selection mapping relationship in LTE release 8 (e.g., tables 5 to 7 above) and the channel selection mapping relationship in LTE release 10 (e.g., tables 8 to 11 above) may be used, and this may be determined by RRC configuration.

In applying LTE rel-8 channel selection, the determination is made by SPS PUCCH resources (i.e. resources indicated by SPS activation PDCCH of a higher layer configured resource set, see table 14)The value of (c). In addition, HARQ-ACK (0) is an ACK/NACK/DTX response for SPS PDSCH transmission. This is to solveThe UE loses ambiguity of the case of PDSCH with DAI-1 and can deterministically transmit an ACK/NACK response to the SPS transmission.

In this case, the TPC field of the PDCCH with DL DAI ═ 1 may be actually used for PUCCH power control. However, in a cell supporting MIMO transmission (or 2 codeword transmission), loss of ACK/NACK bits may occur due to spatial bundling for a PDSCH with DAI ═ 1.

Meanwhile, a case in which PUCCH format 3 is used may be considered.

If the UE receives both the SPS PDSCH and the PDSCH with DL DAI-1, the UE may assume that the TPC field of the PDCCH with DL DAI-1 is used for ARI purposes. The UE may then transmit a 2-bit ACK/NACK (on non-MIMO cells) or a 3-bit ACK/NACK (on MIMO cells) using PUCCH format 3.

In this case, since ACK/NACK bundling is not applied, ACK/NACK bits can be transmitted without loss of ACK/NACK information. Meanwhile, since there is no TPC field for the original TPC command purpose (since the TPC field of the PDCCH having DL DAI ═ 1 is for the ARI purpose), PUCCH power control may be incorrectly performed.

In view of this, the following two methods are proposed for resource allocation for TDD PUCCH format 3 in CA.

The first approach is to reuse the resource allocation for FDD PUCCH format 3 in CA. In this case, one or more TPC fields on the PCell may be used for original purposes and one or more TPC fields on the one or more scells may be used for ARI purposes. ACK/NACK bundling as defined in LTE release 8 may be used if the UE receives PDSCH only on PCell.

The second method is to reuse the resource allocation for TDD PUCCH format 3 when CA is not supported (i.e., in non-CA). Then, the TPC field of the PDCCH with DAI-1 on the PCell may be used for the original purpose, and the TPC fields of all other PDCCHs on the PCell and SCell may be used for the ARI purpose. When the UE receives only the SPS PDSCH or the PDCCH with DL DAI ═ 1 on the PCell, LTE release 8 PUCCH format 1a/1b may be used (i.e., fallback mode operation). LTE release 8 channel selection is used when the UE receives SPS PDSCH and PDSCH with DL DAI ═ 1 but does not receive PDSCH with DL DAI > 1.

ACK/NACK transmission through PUCCH in TDD system

An ACK/NACK bundling method and a resource allocation method in LTE-a (or LTE release 1) are described.

For ACK/NACK feedback in TDD using PUCCH format 3, mode 1 and mode 2 are defined. Mode 1 may support ACK/NACK payload sizes of up to 20 bits. If the indicated number of ACK/NACK bits exceeds 20, spatial bundling is used. If the number of ACK/NACK bits indicated in mode 1 is less than 20, bundling is not supported. Meanwhile, mode 2 is a scheme in which partial bundling (bundling in the time domain or bundling in the CC domain) is applied together with spatial bundling. That is, in mode 2, if the indicated number of ACK/NACK bits exceeds x, spatial bundling is performed simultaneously with partial bundling.

When channel selection is applied to ACK/NACK feedback in TDD using PUCCH format 1b, mode a and mode b are defined. Mode a is a scheme in which any bundling is not supported when the number of indicated ACK/NACK bits is less than 4. Mode b is a scheme in which partial bundling (bundling in the time domain or bundling in the CC domain) is applied together with spatial bundling when the indicated number of ACK/NACK bits exceeds 4.

On the other hand, resource allocation for PUCCH format 3 is defined as follows. A 2-bit TPC field in a PDCCH corresponding to the PDSCH on the PCell is used for the TPC command for the original purpose. The 2-bit TPC field of the PDCCH corresponding to the PDSCH on the SCell is used for ARI purposes. If a PDCCH corresponding to a PDSCH on the SCell is not received and a PDSCH on the PCell is received, PUCCH 1a/1b is used by the scheme defined in LTE release 8.

Hereinafter, an ACK/NACK bundling method and a resource allocation method when there is DL reception only on the PCell will be described.

Example 9

Embodiment 9 relates to spatial bundling in mode 1.

Mode 1 for TDD may support independent ACK/NACK transmission of up to 20 bits. However, if the number of indicated ACK/NACK bits exceeds 20, spatial bundling needs to be applied. Since independent ACK/NACK information is not definitely fed back when spatial bundling is applied, the efficiency of HARQ operation may be reduced, and thus, separate ACK/NACK information needs to be maximally transmitted without bundling. That is, the simple application of spatial bundling to all ACK/NACK bits is undesirable in DL throughput performance. Also, since mode 1 is a scheme of transmitting independent ACK/NACK feedback without change, spatial bundling should be minimally applied. Therefore, it is necessary to perform spatial bundling such that the number of ACK/NACK bits is closest to 20 but less than 20.

A detailed method for performing spatial bundling when the indicated number of ACK/NACK bits exceeds 20 will be described below.

As a first method, spatial bundling in CC units (CC-by-CC) may be considered. According to a first method, spatial bundling may be applied on all DL subframes in one particular CC. In this way, spatial bundling may be performed throughout all subframes with respect to other CCs until the number of ACK/NACK bits to be actually transmitted is less than 20. Spatial bundling may be applied last on the PCell, assuming that the PCell is scheduled more frequently with respect to the SCell.

When TDD is configured to 9DL:1UL (i.e., a configuration for transmitting ACK/NACK for DL transmission in 9DL subframes in one UL subframe, for example, see subframe 2 of UL-DL configuration 5 of table 12), if the number of configured CCs exceeds 2, the ACK/NACK payload size exceeds 20 bits even though spatial bundling is applied to all CCs. Therefore, when the number of configured CCs is 2, space bundling may be applied to all CCs.

When the TDD configuration is not 9DL:1UL, (N) of codewords having two configurations starting from a CC having the last index (or the highest index) on a logical index_{configuredDLsubframe}+N_{CW_SF}-9) CC application space bundling. Space bundling may be applied to the PCell last (i.e., the PCell may be assigned the lowest logical index)Lead). Here, N is_{configuredDLsubframe}Is the number of DL subframes in which ACK/NACK is fed back on one CC. N is a radical of_{CW_SF}Is the total number of codewords for which ACK/NACK is fed back on one subframe on all DL CCs. That is, N may be determined as shown in equation 2_{CW_SF}。

[ equation 2]

In equation 2, N_CW,iIs the number of codewords configured on the ith CC.

As a second method, spatial bundling in units of subframes (subframe by subframe) may be considered. According to a second method, spatial bundling may be applied on all CCs on one particular DL subframe. In this way, spatial bundling may be performed throughout all CCs with respect to other DL subframes until the number of ACK/NACK bits to be actually transmitted is less than 20.

According to the first or second method described above, the number of bundled ACK/NACK bits is 18, 19, or 20. The number of ACK/NACK bits when the first or second method is applied is shown in table 17 below according to the number of CCs configured for the UE.

[ Table 17]

The first method may maximally support independent ACK/NACK transmission for the PCell with respect to the second method, and may be simply expressed. If the indicated number of ACK/NACK bits exceeds 20, it is preferable to perform spatial bundling (i.e., apply the first method) CC by CC.

Example 10

In embodiment 10, a detailed application example of the above-described mode 2 and mode b is described. Mode 2 is a scheme in which partial bundling (bundling in the time domain or bundling in the CC domain) is applied together with spatial bundling for ACK/NACK feedback in TDD using PUCCH format 3. Mode b is a scheme in which partial bundling (bundling in the time domain or bundling in the CC domain) is applied together with spatial bundling for ACK/NACK feedback in TDD using PUCCH format 1b when channel selection is applied in the case where the indicated number of ACK/NACK bits exceeds 4.

Mode 2 may be advantageously applied to improve ACK/NACK performance for power limited UEs. When comparing FDD supporting ACK/NACK of up to 10 bits with TDD supporting ACK/NACK of up to 20 bits, TDD has smaller UL coverage than FDD. In addition, mode 1 (in which spatial bundling is applied when the indicated number of ACK/NACK bits exceeds 20 and spatial bundling is not applied when the indicated number of ACK/NACK bits is 20 or less) cannot support ACK/NACK feedback when the number of DL CCs exceeds 2 in TDD9DL-1UL configuration. For example, to support ACK/NACK feedback on 5 DL CCs and in TDD9DL-1UL configuration, a total of 45 ACK/NACK bits are required even if spatial bundling is applied. Therefore, in order to support ACK/NACK feedback at least in TDD9DL-1UL configuration, the above-described mode 2 for PUCCH format 3 needs to be supported.

Hereinafter, spatial bundling applied to the mode 2 and the mode b will be described in detail.

Example 10-1

In embodiment 10-1, spatial bundling in the time domain is described. In addition to spatial bundling, time domain bundling in this embodiment may also be performed.

Time domain bundling, which is spatial bundling, may be performed without additionally modifying the 2-bit DAI defined in LTE release 8 on each CC. Also, in applying time domain bundling, time domain bundling may be simply applied on each CC without considering various forms of CA. That is, it is sufficient to determine a time domain bundling method for various cases of CA. Since the size of ACK/NACK information bits as a result of application of time-domain bundling is 10 bits, the PUCCH format 3 structure of LTE release 10 can be used as a PUCCH format to be used for ACK/NACK transmission.

The DAI value is sequentially increased with respect to all allocated PDCCHs. Therefore, when using DAI, the UE cannot recognize a case where the last PDCCH is lost in the time-domain bundling window. To solve this problem, the DAI value for the last detected PDCCH on each CC may be input to an ACK/NACK mapper and then encoded.

Fig. 40 is a diagram illustrating an exemplary time-domain partial bundling. In the example of fig. 40, ACK/NACK bundling is applied over 4 subframes on each CC.

In the first CC of fig. 40, the UE has received a PDCCH with DAI-0 in the first subframe and a PDCCH with DAI-1 in the second subframe, but has not received a PDCCH with DAI-2 in the third subframe. Then, since the UE does not know whether the last PDCCH has been transmitted (DAI ═ 2), the UE can recognize that all PDCCHs in the time-domain bundling window have been received. In addition, fig. 40 shows a case in which each of PDSCHs scheduled through a received PDCCH is successfully decoded (i.e., ACK), and as a result, ACK is generated as bundled ACK/NACK information. Together with the generated ACK information, the UE may encode the last received DAI value, i.e., DAI ═ 1. The UE encodes and transmits ACK and DAI (DAI ═ 1), and then, the BS can recognize that the UE loses PDCCH (DAI ═ 2).

The time domain bundling operation on the second CC of fig. 40 is similar to that on the first CC. The UE may encode the last received DAI value (i.e., DAI ═ 0) along with the ACK information. Since the UE encodes and transmits ACK and DAI (DAI ═ 0), the BS can recognize that the UE loses PDCCH (DAI ═ 1).

In the third CC of fig. 40, the UE receives a PDCCH (DAI ═ 0) in the first subframe and receives a PDCCH (DAI ═ 2) in the third subframe. Even if the UE does not recognize transmission of a PDCCH (DAI ═ 1) in the second subframe, the UE can recognize that it itself loses the PDCCH (DAI ═ 1) because the DAI values of the received PDCCHs are not sequentially increased. Although fig. 40 shows a case in which each of the PDSCHs scheduled by the received PDCCH is successfully decoded (i.e., ACK), the UE may generate NACK as bundled ACK/NACK information because transmission of one PDCCH is lost.

In the fourth CC of fig. 40, the UE receives only a PDCCH (DAI ═ 0) and generates ACK information when a PDSCH scheduled by the PDCCH is successfully decoded. The generated ACK information may be encoded together with the last received DAI value (DAI ═ 0).

In the fifth CC of fig. 40, the UE receives only a PDCCH with DAI ═ 0. The UE does not know that a PDCCH with DAI-1 has been transmitted in the fourth subframe. Fig. 40 shows a diagram in which a PDSCH scheduled through a PDCCH received by a UE is not successfully decoded (i.e., NACK). Accordingly, the UE may generate NACK information.

Thus, when time-domain spatial bundling is applied, the 2-bit TDDDAI of LTE release 8 (i.e., as a PDCCH accumulation counter) can be reused on each CC without modification.

As an example of PUCCH format 3 for application of mode 2, an ACK/NACK state of each CC before channel coding may be defined as shown in table 18.

[ Table 18]

Using the ACK/NACK state of table 18, the result of bundled ACK/NACK encoded together with the DAI value of the last received PDCCH on each CC in fig. 40 is expressed as follows: a '01 (DAI ═ 1)' on the first CC, a '01 (DAI ═ 0)' on the second CC, a '11 (NACK)' on the third CC, a '00 (DAI ═ 0)' on the fourth CC, and a '11 (NACK)' on the fifth CC.

The aggregation of ACK/NACK payloads for 5 CCs before performing channel coding in PUCCH format 3 to which mode 2 is applied is '0100110011'.

The principle of the present invention for the above-described mode 2 can be equally applied to the mode b. For the application of mode b, a relationship between a channel selection mapping relationship (mapping relationship between PUCCH resources and ACK/NACK bits) and a NACK/DAI value may be defined.

Therefore, when time-domain bundling is used, each ACK/NACK response on each CC may be expressed as bundled ACK/NACK information.

Example 10-2

In embodiment 10-2, CC domain space bundling is described. In addition to spatial bundling, time domain bundling in this embodiment may be performed.

In CC domain bundling, it is preferable to use DAI as an indicator indicating the total number of PDSCHs (or corresponding PDCCHs) scheduled in a bundling window consisting of a plurality of CCs in one subframe, rather than using DAI as an accumulation counter of PDSCHs (or corresponding PDCCHs) scheduled in a plurality of subframes on each CC as in the conventional DAI. This is because when the DAI indicates the total number of PDSCHs (or PDCCHs) per subframe, it is not necessary to provide a solution for the case in which the UE discards the last PDCCH in time.

Then, the UE may transmit an ACK when the number of ACKs generated for DL transmissions successfully decoded in the bundling window is equal to the total number of PDSCHs (or PDCCHs) in the bundling window, and otherwise, the UE transmits a NACK (at this time, DTX is expressed as a NACK).

Hereinafter, the application of CC domain bundling to mode b and mode 2 will be described in detail.

Channel selection for applying CC field bundling to mode b is described with reference to fig. 41.

In this case, it is generally assumed that the channel selection mapping relationship of LTE release 10 (e.g., tables 8 to 11 above) is applied.

If an ACK/NACK PUCCH resource that is implicitly determined (i.e., derived from a CCE index of a PDCCH) is used, a PUCCH resource that is dynamically linked with a PDCCH for scheduling on a PCC (or PCell) may be first selected in each subframe.

ACK/NACK resource mapping in LTE release 8 (e.g., tables 5 to 7 above) may be applied if PDSCH is scheduled only on PCC (or PCell) in a multi-CC configuration. That is, the operation of the fallback mode in LTE release 8 may be performed.

In the example of fig. 41, it is assumed that two cells (PCC and SCell) are configured in each subframe.

In the TDD 2DL:1UL configuration of fig. 41, in the first subframe, since the PDSCH is not scheduled on the PCC and is scheduled on the SCC, the PUCCH resource is determined from the CCE index of the PDCCH for scheduling the SCC PDSCH. In the second subframe, a PUCCH resource may be determined from a CCE index of a PDCCH for scheduling the PCC PDSCH. Such PUCCH resources may be used to use a channel selection operation. For example, ACK/NACK transmission may be performed using a channel selection mapping relationship as shown in table 8.

In TDD 3DL:1UL configuration, PDSCH is scheduled on PCC only in all subframes. In this case, the fallback mode operation may be performed as described above. For example, ACK/NACK transmission may be performed through PUCCH format 1b using a channel selection mapping relationship as shown in table 6.

In TDD 4DL:1UL configuration, since PDSCH is scheduled on both PCC and SCC in the first subframe, PUCCH resources may be determined based on CCE index of PDCCH for scheduling PDSCH on PCC. Since the PDSCH is not scheduled in the second subframe and is scheduled on only one cell (PCC or SCC) in the third and fourth subframes, the PUCCH resource may be determined based on the CCE index of the PDCCH of the corresponding PDSCH. In this way, a channel selection operation may be performed using the determined PUCCH resources. For example, ACK/NACK transmission may be performed using the channel selection mapping relationship shown in table 10.

An example of applying CC domain bundling to mode 2 is described with reference to fig. 42.

In the example of fig. 42, it is assumed that the maximum number of ACK/NACK bits is 12 and the maximum bundling window is 2 (i.e., a maximum of two CCs is included in one bundling window).

To maintain independent ACK/NACK transmissions, bundling is applied gradually until the number of ACK/NACK bits is closest to 12 and less than 12.

In addition, the PCell (or PCC) is not included in the bundling window. That is, the bundling window is configured only for the scell (scc). The bundling windows may be applied in ascending order of CC index.

As shown in fig. 42, CC domain bundling may gradually apply a bundling window (consisting of 2 CCs) until the number of ACK/NACK bits (the number of ACK/NACK bits after applying spatial bundling) becomes 12 or less.

In the 2DL:1UL configuration of fig. 42, since the number of ACK/NACK bits after performing spatial bundling is 10, a bundling window is not configured.

In the 3DL:1UL configuration, since the number of ACK/NACK bits after performing spatial bundling is 15, a bundling window is configured. The number of ACK/NACK bits after configuring the bundling window for two CCs (SCC3 and SCC4) is 12, and thus, the bundling window is not configured any more.

In the 4DL:1UL configuration of fig. 42, since the number of ACK/NACK bits after performing spatial bundling is 20, a bundling window is configured. When a bundling window for two CCs (SCC3 and SCC4) is configured, 16-bit ACK/NACK is generated and thus, another bundling window is configured. If another bundling window is configured for two CCs (SCC1 and SCC2), a 12-bit ACK/NACK is generated and, therefore, the bundling window is not configured any more.

Accordingly, when CC field partial bundling is used, a bundling result (e.g., a result of a logical and operation) for all ACK/NACK bits in a bundling window is transmitted as ACK/NACK information. The DAI in the PDCCH indicates the total number of PDSCHs scheduled on all CCs in one subframe. The maximum size of the bundling window for PUCCH format 3 may be determined to be 2 (i.e., at most two CCs (or cells) may configure one bundling window).

Example 11

Embodiment 11 relates to an ACK/NACK transmission method through PUCCH format 3 when a PDCCH/PDSCH is received only on a PCell (hereinafter, PCell-only reception). In particular, PCell-only reception in TDD is described in detail.

When no PDCCH corresponding to the PDSCH is received on the SCell and only the PDCCH corresponding to the PDSCH is received on the PCell, the PUCCH format 1a/1b resources of LTE release 8 may be used (i.e., may operate in a fallback mode).

In FDD, a fallback mode may be applied for the purpose of using PUCCH resources defined in LTE release 8 and the purpose of explicitly determining PUCCH resources even if ARI is not received on SCell.

If the TPC field is used for ARI purpose on SCell, ACK/NACK resources may be ambiguous with PCell-only reception. To solve this problem, ACK/NACK multiplexing or ACK/NACK bundling defined in the LTE release 8 TDD system may be applied. However, if ACK/NACK bundling or time domain bundling is applied, some ACK/NACK information cannot be transmitted, and thus, a considerable loss of DL throughput may occur. Also, since partial ACK/NACK states are overlapped in an ACK/NACK mapping relationship, ACK/NACK performance of 4-bit ACK/NACK in an LTE release 8 TDD system cannot be guaranteed.

Therefore, an ACK/NACK transmission method for the PCell-only reception case is proposed below.

Example 11-1

According to this embodiment, when a single PDSCH is received on the PCell, resources of PUCCH format 1a/1b defined in LTE release 8 may be used. In this case, the use of DAI and ARI may be defined as follows.

Fig. 43 is a diagram illustrating an example of use of DAI and TPC.

As shown in fig. 43, as in the LTE rel-8 TDD system, DAI on PCell may be used as an accumulation counter for PDCCH (or PDSCH). As in LTE release 8 TDD systems, the DAI on the SCell may be used as an accumulation counter for the PDCCH (or PDSCH). The DAI on the SCell may be configured to be '00'. In the illustrated example of fig. 43, the DAI values of the PDCCHs of the scells are all configured to '00'. PDCCH DCI may also be scheduled in the common search space if the DAI value of PDCCH on SCell is configured identically to '00'. In terms of UE implementation, the predefined value '00' may be used as a virtual CRC (i.e., for error detection when the DAI value is not '00').

As shown in fig. 43, the TPC field of a PDCCH first allocated on the PCell (i.e., a PDCCH with DAI ═ 00) is used for a TPC command of an original purpose. The TPC field of all other PDCCHs (including PCell and SCell) except the PDCCH with DAI ═ 00 on PCell is used for ARI purpose, and the field used for ARI purpose in PDCCH should have the same value in all PDCCHs.

The UE behavior in this case may be defined as follows.

If there is a PDSCH transmission on the PCell without a corresponding PDCCH (i.e., SPS PDSCH only),

if there are no other PDSCH transmissions,

use LTE release 8 PUCCH format 1a/1 b.

If not, the sum of the square root and the square root,

PUCCH format 3 is used.

Exceptionally, a TPC field in a PDCCH with DAI ═ 00' is used as an ARI.

Otherwise

If there is a single PDSCH with DAI ═ 00 'on the PCell or a single PDSCH with DAI ═ 00' on the PCell for indicating DLSPS release,

use LTE release 8 PUCCH format 1a/1 b.

If not, the sum of the square root and the square root,

PUCCH format 3 is used.

In the above explanation, the case where 'there is PDSCH transmission without a corresponding PDCCH' corresponds to DL SPSPDSCH. Also, a single PDSCH ' having a DAI of ' 00 ' indicates that the DAI field in the PDCCH corresponding to the PDSCH is 00.

Embodiment 11-1 is applicable to all cases including 9DL:1UL subframe configuration for TDD ACK/NACK feedback and time domain/CC domain bundling for mode 1 and mode 2.

The above-mentioned example 11-1 is summarized as follows.

The resources of LTE Release 8 PUCCH format 1a/1b and PUCCH format 1a/1b are used in the following cases: (1) a case in which 'a single PDSCH without a corresponding PDCCH' exists on the PCell, (2) a case in which 'a single PDSCH with a corresponding PDCCH' exists only on the PCell and a DAI value in the PDCCH is 00, or (3) a case in which 'a single PDCCH indicating a DL SPS release' exists only on the PCell and a DAI value in the PDCCH is 00.

LTE release 8 PUCCH format 3 is used for cases other than the above (1), (2), and (3) cases.

If 'PDSCH without corresponding PDCCH (i.e., DL SPS PDSCH)' does not exist on PCell, the following operation is performed. If 'PDSCH with corresponding PDCCH' exists on PCell and the DAI value of PDCCH is 00, the TPC field of PDCCH is used for the actual TPC command. If there is 'PDCCH indicating DL SPS release' and the DAI value of PDCCH is 00, the TPC field of PDCCH is used for the actual TPC command. In other cases, all TPC fields are used as ARI.

In other cases (i.e., there is 'PDSCH without corresponding PDCCH (i.e., DL SPSPDSCH)') on PCell, all TPC fields of PDCCH are used as ARI.

In addition, in all of the above cases, all fields used as ARI in PDCCH have the same value.

Example 11-2

In FDD, the TPC field on the SCell is used for ARI purposes and the TPC field on the PCell is used for the original TPC purposes. According to this embodiment, in TDD, in a similar manner as in FDD, the TPC field in PDCCH on PCell is used for original TPC purpose and the TPC field in PDCCH on SCell is used for ARI purpose. In this case, the same PUCCH power control operation as in the conventional LTE release 8 can be performed without modification.

Fig. 44 is a diagram illustrating another example of use of DAI and TPC.

As in the example of fig. 44, with respect to a UE that receives a PDSCH only on a PCell, a DAI field of a PDCCH on the PCell may be used for ARI purposes. Using such a DAI field is available in mode 1 because mode 1 does not have to support DAI in time domain/CC domain bundling. In addition, fields used as ARI of PDCCH (DAI field on PCell and TPC field on SCell) should have the same value.

In the illustrated example of fig. 44, the DAI values of the PDCCHs on the scells are all configured to '00'. The description thereof is omitted because it is the same as that of fig. 43.

The UE behavior based on the above description is defined as follows.

For scheduling one or more PDSCHs or one or more PDCCH indicating SPS release on PCell

the/TPC field is used for TPC commands.

The v DAI field is used as an ARI for PUCCH format 3.

For a PDCCH scheduling PDSCH on the SCell,

the TPC field is used as an ARI for PUCCH format 3.

Exceptionally, only for SPS PDSCH without PDCCH,

use LTE release 8 PUCCH format 1a/1b (RRC configured for SPS).

All fields used as ARI in PDCCH have the same value.

The above embodiments 9 to 11 mainly relate to detailed application examples of the present invention for ACK/NACK transmission through PUCCH in a TDD system.

Example 12

In this embodiment 12, a method of using ARI in 'PDCCH indicating DL SPS release' on PCell is described.

In particular, embodiment 12 relates to a method for transmitting ACK/NACK via PUCCH format 3 by reusing the TPC field of 'PDCCH indicating DL SPS release' when receiving a single 'PDCCH indicating DL SPS release' on PCell in case there is no PDSCH on one or more scells and SPS PDSCH (i.e., PDSCH without corresponding PDCCH) on PCell. That is, a method for transmitting ACK/NACK when there is no SPS PDSCH (i.e., there is no PDSCH of a corresponding PDCCH) and a single PDSCH is received on a PCell has been described. In this embodiment, another ACK/NACK transmission method when there is no PDSCH (i.e., PDSCH with/without corresponding PDCCH) and 'PDCCH indicating DL SPS release' is received on PCell is described.

One method of using ARI in FDD is as follows.

The TPC field of the PDCCH' indicating DL SPS release on the PCell is used for ARI purposes. The TPC field of the PDCCH other than 'PDCCH indicating DL SPS release' is used on the PCell for the TPC command of the original purpose. Also, the TPC field of the PDCCH on the SCell is used as the ARI. The UE assumes that all ARI values on PCell and SCell are the same.

The UE behavior based on the above description may be defined as follows.

If there is a PDSCH on the PCell without a corresponding PDCCH (i.e., an SPS-only PDSCH),

use LTE release 8 PUCCH format 1a/1 b.

When there is no corresponding PDCCH, a PUCCH resource may be selected from RRC-configured resources through a TPC field of a PDCCH corresponding to SPS or through a value of the TPC field in the PDCCH during SPS activation (explicit mapping).

When there is a corresponding PDCCH, the PUCCH resource may be selected by a prescribed rule based on the CCE index of the PDCCH (e.g., by the equation defined in LTE rel-8) (implicit mapping).

Otherwise, if there is only a single PDCCH indicating DL SPS release on the PCell (i.e., only SPS release PDCCH).

Use PUCCH format 3.

Additionally, the TPC field of the PDCCH indicating DL SPS release may also be used as the ARI.

If not, then,

use PUCCH format 3.

Next, a method of using DAI and ARI in TDD is as follows.

As in LTE release 8, the DAI on the PCell is used as an accumulation counter for PDCCH/PDSCH. The DAI for the SCell is configured to a preset value (e.g., '00') such that DCI is scheduled on a common search space. In terms of UE implementation, this preset value may be used as a virtual CRC.

The TPC field of a PDCCH first allocated on the PCell (i.e., a PDCCH with DAI 1 or DAI 00) is used for a TPC command of an original purpose. The TPC field of all other PDCCHs except the PDCCH first allocated on the PCell (i.e., other PDCCHs on the PCell and the PDCCH on the SCell) is used for ARI purposes. The TPC field when DAI ═ 00' is also used as ARI in the other PDCCHs above. In addition, the UE assumes that all ARI values are the same.

The UE behavior based on the above description may be defined as follows.

If there is PDSCH transmission on the PCell and there is no PDCCH corresponding to the PDSCH (i.e., SPS PDSCH only),

if there is no other PDSCH transmission (i.e., if there is only SPS PDSCH),

use LTE release 8 PUCCH format 1a/1 b.

Else if (i.e., if the SPS PDSCH includes other additional transmissions),

use PUCCH format 3-

Exceptionally, the TPC field in the PDCCH with DAI ═ 00' is also used as the ARI

Otherwise, there is no SPS

If there is a single PDSCH transmission only on the PCell with only DAI ═ 00' (only the first PDCCH),

use release 8 PUCCH format 1a/1 b.

Implicit mapping can be used by rules such as the equation in release 8 TDD based on CCE indices of PDCCH.

PUCCH resources (explicit mapping) may be selected from RRC configured resources during SPS activation by the TPC field of the PDCCH corresponding to SPS or by the value of the TPC field in the PDCCH.

Else, if there is a single PDCCH on PCell only indicating downlink SPS release on PCell only (SPS release only),

PUCCH format 3 is used.

As an exception, the TPC field in the PDCCH indicating downlink SPS release is also used as ARI

If not, the sum of the square root and the square root,

PUCCH format 3 is used.

Example 13

Embodiment 13 relates to a method of using different TPC fields depending on whether there is an SPS PDSCH.

As described above, the ACK/NACK response is generated with respect to three cases. Case 1 relates to a PDSCH with a corresponding PDCCH, case 2 relates to a PDCCH indicating DL SPS release, and case 3 relates to a PDSCH without a corresponding PDCCH. Case 3 is also referred to as ACK/NACK for SPS PDSCH.

In the description of this embodiment, for the 'PDCCH' indication case 1 or case 2 and the 'SPS PDSCH' indication case 3 related to the ACK/NACK response, an operation is described in which a specific UE performs DL reception for the above three cases and performs ACK/NACK for the DL reception. At the n-thThe ACK/NACK response transmitted in the UL subframe has a length in the n-K subframe (where K ∈ K and K: { K: } K ∈ K } K₀,k₁,…k_M-1And see table 12) for the ACK/NACK responses of the DL transmissions for the above three cases. Hereinafter, description of the ACK/NACK transmission subframe position will be omitted.

If the ACK/NACK is transmitted from the UE through various formats, the complexity of blind decoding, in which the BS interprets the ACK/NACK, increases. In order to improve performance in the BS, such as complex blind decoding, and to efficiently use resources, a PUCCH format configured by a higher layer may be used. Hereinafter, a method of using different TPC fields depending on whether there is an SPS PDSCH will be described in detail.

When configuring one serving cell, the use of the (2-bit) TPC field may be determined as follows. When SPSPDSCH is present, the TPC field in all PDCCHs may be used as ARI, and the UE may assume that the ARI value is the same in all PDCCHs. Meanwhile, if there is no SPS PDSCH, a TPC field of a PDCCH having DL DAI ═ 1 may be used for the original TPC command, and a TPC field of a PDCCH having DL DAI >1 may be used as an ARI. The UE may assume that the ARI values are the same in all PDCCHs with DLDAI > 1.

In addition, when one serving cell is configured, the use of the PUCCH format may be determined as follows. If the UE receives SPS PDSCH 'only', LTE release 8 PUCCH format 1a/1b may be used. Alternatively, if the UE 'only' receives a single PDCCH with DLDAI ═ 1, LTE release 8 PUCCH format 1a/1b may be used. In other cases, PUCCH format 3 may be used as a PUCCH format configured by a higher layer.

If DL DAI is used as a simple counter (PDCCH accumulation counter), the resource allocation of TDD PUCCH format 3 in CA may be the same as in a single carrier (or non-CA). That is, the resource allocation method for the PCell may use the same method as the resource allocation method in the non-CA. In case of CA, PUCCH resource allocation for a plurality of cells may be determined as follows.

If more than one serving cell is configured, the use of the TPC field may be determined as follows. When SPSPDSCH is present, the TPC fields of all PDCCHs on the PCell and one or more scells may be used for ARI purposes, and the UE may assume that ARI values on all PDCCHs on the PCell and one or more scells are the same. Meanwhile, if there is no SPS PDSCH, only the TPC field of the PDCCH on the PCell with DL DAI ═ 1 may be used for the original TPC command, and the TPC fields of all other PDCCHs on the PCell and SCell(s) may be used for ARI purposes. The UE may assume that the ARI values on all PDCCHs on the PCell and the SCell(s) are the same.

If more than one serving cell is configured, the use of PUCCH format may be used as follows. If the UE receives SPS PDSCH 'only', LTE release 8 PUCCH format 1a/1b may be used. Alternatively, if the UE 'only' receives a single PDCCH with DLDAI ═ 1, LTE release 8 PUCCH format 1a/1b may be used. For other cases, PUCCH format 3 may be used as a PUCCH format configured by a higher layer.

Example 14

Embodiment 14 relates to a PUCCH resource allocation method for TDD HARG ACK/NACK response transmission in consideration of the above-described embodiments.

In the conventional LTE release 8/9 system, a loss of independent ACK/NACK information has occurred because ACK/NACK bundling (spatial bundling and/or time-domain bundling) is applied to ACK/NACK transmissions that exceed a prescribed bit size (e.g., 4 bits). In LTE release 10 (or LTE-a) systems, PUCCH format 3 is designed to support transmission of up to 20 bits of independent ACK/NACK information. In a CA and/or TDD support system, since a case in which 20 bits or more of ACK/NACK is transmitted may occur, a method for efficiently utilizing resources while transmitting ACK/NACK information without loss is required.

Fig. 45 is a diagram illustrating an example of the present invention for use of a TPC field in a PDCCH. In the example of fig. 45, the ARI is information indicating resources of PUCCH format 3 for ACK/NACK transmission. Although the TPC field of the PDCCH with DLDAI ═ 1 on the PCell is used for the original TPC command, the TPC fields of other PDCCHs on the PCell and SCell are used as ARI. The UE may assume that the ARI values on the PCell and SCell are the same. Therefore, even if only one ARI is detected, the resource of PUCCH format 3 can be determined.

When the TPC field is reused as the ARI, the accuracy of PUCCH power control may be reduced. However, since the resources of the PUCCH format 3 can be surely determined by the ARI information, transmission of ACK/NACK information without loss using the PUCCH format 3 may be preferable for the entire system with respect to a reduction in the accuracy of PUCCH power control.

In the example of fig. 45, when the UE succeeds in detecting at least one PDCCH including an ARI, an ACK/NACK response may be transmitted using PUCCH format 3 indicated by the ARI. However, if the UE 'only' detects a PDCCH without an ARI (i.e., a PDCCH with DAI ═ 1 on the PCell), the UE cannot obtain ARI information and cannot determine a PUCCH format 3 resource. In this case, the ACK/NACK response may be transmitted without information loss using a legacy format, i.e., PUCCH format 1a/1b of LTE release 8/9.

Accordingly, a resource allocation method may be provided which is capable of transmitting an ACK/NACK response for DL transmissions (PDCCH and/or PDSCH) transmitted in one or more DL subframes without any loss. In addition, since the PUCCH format and PUCCH resources are determined in the same manner regardless of CA or non-CA, the operations of the BS and the UE can be simply and clearly specified.

Fig. 46 is an overall flowchart illustrating various embodiments proposed in the present invention. In the example of fig. 46, a description is given on the premise that PUCCH format 3 is configured for a UE by a higher layer.

In step S4610, the UE determines whether a PDSCH with DAI-1 (i.e., a PDSCH corresponding to a PDCCH with DAI-1) is received on the PCell only.

If the result of step S4610 is YES, step S4620 is executed. Since the TPC field of the PDCCH with DAI-1 on the PCell is used for the original TPC command, the UE cannot acquire ARI information when only the PDCCH with DAI-1 is received. Therefore, the UE does not use PUCCH format 3. The UE may transmit the ACK/NACK using PUCCH format 1a/1 b. The resources of the PUCCH formats 1a/1b may be determined through implicit mapping (i.e., through PUCCH resource indexes derived from CCE indexes of the PDCCH).

Meanwhile, if the result of step S4610 is no, step S4630 is performed. In step S4630, the UE determines whether a single PDSCH without PDCCH on the PCell only has been received.

If the result of step S4630 is YES, step S4640 is executed. Since the UE has not received the PDCCH, the UE cannot acquire ARI information and does not use PUCCH format 3. The UE may transmit the ACK/NACK using PUCCH format 1a/1 b. Here, since the PDCCH has not been received, the UE cannot derive a PUCCH resource index derived from a PDCCH CCE index. Accordingly, the UE may determine the PUCCH resource index from information included in the SPS activation PDCCH (e.g., information indicated by reuse of the TPC field in the SPS activation PDCCH).

If the result of step S4630 is NO, step S4650 is performed. In step S4650, the UE determines whether 'PDSCH with DAI-1' and another 'PDSCH without PDCCH' on the PCell only have been received.

If the result of step S4650 is YES, step S4660 is executed. Even in this case, the UE uses PUCCH format 1a/1b instead of PUCCH format 3 because ARI information cannot be obtained. Here, the UE may transmit ACK/NACK information through a channel selection scheme in order to prevent loss of the ACK/NACK information. Channel selection may be performed such that PUCCH resources are selected from a (═ 2 or 3) PUCCH resources. Here, the value of a may be determined according to the number of codewords (or transport blocks) of the PDSCH.

Meanwhile, if the result of step S4650 is no, step S4670 is performed. In step S4670, the UE may determine whether the value of ARI (i.e., TPC field) of PDCCH in which the DAI value is not 1 (i.e., DAI >1) is equal to the ARI (i.e., TPC field) values of all PDCCHs on the one or more scells.

If the result of step S4670 is YES, step S4680 is performed. In this case, the UE may transmit ACK/NACK information using PUCCH format 3 resources indicated by the ARI. The UE assumes that the ARI value is the same in all PDCCHs and may perform step S4680 using the ARI value in at least one PDCCH.

Meanwhile, if the result of step S4670 is no (i.e., if ARI values on the PCell and the SCell (S) are not equal), the UE may discard the received PDCCH.

In summary, for 'PDSCH with PDCCH', 'PDSCH without PDCCH (SPS-PDSCH)' and 'SPS release PDCCH' for which the UE should transmit ACK/NACK, the following UE behavior may be defined. However, the scope of the present invention is not so limited and TDD HARQ ACK/NACK resource allocation and transmission operations may be performed by available combinations of the various embodiments of the present invention.

First, the operation of the non-CA system may be the same as the 'PCell-only reception' operation in the CA environment. That is, the TDD HARQ ACK/NACK resource allocation and transmission operation when one serving cell is configured for the UE may be the same as the TDD HARQ ACK/NACK resource allocation and transmission operation when a PDSCH and/or a PDCCH is received only on a PCell in case more than one serving cell is configured. Therefore, hereinafter, when only one serving cell is configured, the description of the operation on the PCell may be replaced with the operation on the serving cell.

If the DAI in the PDCCH of the PCell corresponding to the PDSCH is 1, the TPC field is used for the original power control purpose. If the DAI in the PDCCH corresponding to the PDSCH is greater than 1, the TPC field is used as the ARI. The TPC field in the PDCCH corresponding to all PDSCHs on the SCell is used as the ARI. The UE assumes that all ARI values are the same.

If the UE receives only one SPS-PDSCH on the PCell only, the UE reverts to PUCCH format 1a/1 b.

If the UE receives only a PDSCH with DAI-1 (i.e., a PDSCH with DAI-1 corresponding to a PDCCH), the UE falls back to PUCCH format 1a/1 b.

If one PDSCH with DAI-1 and one SPS-PDSCH are received on the PCell only, ACK/NACK transmission is performed by using a channel selection scheme of PUCCH format 1 b. The number a of PUCCH resources for channel selection is 2 or 3.

If one or more PDSCHs having DAI >1 (PDCCH having DAI >1 corresponding to the PDSCH) are received, ACK/NACK transmission is performed using PUCCH format 3 resources indicated by the ARI.

If one or more PDSCHs are received on the SCell, ACK/NACK transmission is performed using PUCCH format 3 resources indicated by the ARI.

Accordingly, for all cases where one of 'PDSCH with PDCCH', 'PDSCH without PDCCH (SPS-PDSCH)', and 'SPS release PDCCH' is received only on the PCell or on the PCell and one or more scells, ACK/NACK information can be correctly and efficiently transmitted without losing ACK/NACK information.

A detailed description of the preferred embodiments of the invention has been given to enable any person skilled in the art to make or use the invention. Although the present invention has been described with reference to the preferred embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention described in the appended claims. Thus, the present invention is not intended to be limited to the particular embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms than those set forth herein without departing from the spirit or essential characteristics of the invention. The above description is therefore to be construed in all aspects as illustrative and not restrictive. The scope of the invention should be determined by reasonable interpretation of the appended claims and all changes which come within the equivalent scope of the invention are intended to fall within the scope of the invention. In addition, claims that are not explicitly dependent on each other may be combined to provide an embodiment, or new claims may be added by modification after filing the present application.

[ INDUSTRIAL APPLICABILITY ]

The invention is suitable for various mobile communication systems.

Claims

1. A method for transmitting acknowledgement/negative acknowledgement (ACK/NACK) information in a wireless communication system, the method being performed by a User Equipment (UE), and the method comprising:

determining a physical uplink control channel, PUCCH, format and PUCCH resources over which ACK/NACK information for downlink transmission in a downlink subframe set comprising M downlink subframes, where M >1, is to be transmitted; and the number of the first and second groups,

transmitting the ACK/NACK information using the PUCCH format and the PUCCH resources in one uplink subframe,

wherein more than one serving cell is configured for the UE and comprises one primary cell, PCell, and at least one secondary cell, SCell, and

wherein the ACK/NACK information is transmitted using PUCCH format 1b when the ACK/NACK information corresponds to one Physical Downlink Shared Channel (PDSCH) without a corresponding Physical Downlink Control Channel (PDCCH) received on the PCell in the downlink subframe set and the ACK/NACK information further corresponds to one PDSCH received on the PCell indicated by detection of a corresponding PDCCH having a Downlink Assignment Index (DAI) with a value of 1 or semi-persistent scheduling (SPS) release of a PDCCH having a DAI with a value of 1.

2. The method of claim 1, wherein the PUCCH resources are selected from "A" PUCCH resources, where "A" is 2 or 3.

3. The method of claim 2, wherein one of the "a" PUCCH resources is determined according to a higher layer configuration, and

wherein other ones of the "A" PUCCH resources are determined using a Control Channel Element (CCE) index of a corresponding PDCCH.

4. The method of claim 2, wherein "a" is determined based on a number of downlink transmitted transport blocks in the downlink subframe set.

5. The method of claim 1, wherein the ACK/NACK information is transmitted by using 2 bits in the one uplink subframe.

6. The method of claim 1, wherein the wireless communication system is a Time Division Duplex (TDD) system.

7. A user equipment, UE, for transmitting acknowledgement/negative acknowledgement (ACK/NACK) information in a wireless communication system, the UE comprising:

a receiving module for receiving a downlink signal from a base station BS;

a transmitting module for transmitting an uplink signal to the BS; and

a processor for controlling the UE including the receiving module and the transmitting module,

wherein the processor is configured to: determining a physical uplink control channel, PUCCH, format and PUCCH resources over which ACK/NACK information for downlink transmission in a downlink frame subset comprising M downlink subframes is to be transmitted, where M > 1; and transmitting, by the transmitting module, the ACK/NACK information in one uplink subframe using the PUCCH format and the PUCCH resource,

8. The UE of claim 7, wherein the PUCCH resources are selected from "A" PUCCH resources, where "A" is 2 or 3.

9. The UE of claim 8, wherein one of the "A" PUCCH resources is determined from a higher layer configuration and

10. The UE of claim 8, wherein "a" is determined based on a number of downlink transmitted transport blocks in the downlink subframe set.

11. The UE of claim 7, wherein the ACK/NACK information is transmitted by using 2 bits in the one uplink subframe.

12. The UE of claim 7, wherein the wireless communication system is a time division duplex, TDD, system.