KR20090084996A - Method and apparatus of supporting harq - Google Patents

Abstract

A method and an apparatus for supporting HARQ are provided to reduce signaling overhead and to make an HARQ and AMC operation clear by transmitting the retransmission data and the CQI together. An initial uplink grant is received on a downlink channel(S510). The uplink data is transmitted on the uplink channel using the initial uplink grant(S520). The retransmission request of the uplink data is received(S530). At least one transmission parameter of the CQI(channel quality indicator) is determined from the initial uplink grant(S560). The CQI is multiplexed with the retransmission data of the uplink data(S570). The resource quanatiy of the CQI transmission is determined based on at least one transmission parameter. The multiplexed data is transmitted on the uplink channel(S580).

Description

METHOD AND APPARATUS OF SUPPORTING HARQ}

The present invention relates to wireless communication, and more particularly, to a method and apparatus for supporting a hybrid automatic repeat request (HARQ) in a wireless communication system.

Wireless communication systems are widely deployed to provide various kinds of communication services such as voice and data. In general, a wireless communication system is a multiple access system capable of supporting communication with multiple users by sharing available radio resources (bandwidth, transmission power, etc.). Examples of multiple access systems include 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, and single carrier frequency (SC-FDMA). division multiple access) system.

Recently, wireless communication has been developed to satisfy high frequency efficiency and reliable communication requirements. Unfortunately, due to the fading channel environment and interference due to various causes, packet errors limit the capacity of the entire system.

Hybrid Automatic Repeat Request (HARQ), an Automatic Repeat Request (ARQ) protocol combined with Forward Error Correction (FEC), is one of the key technologies for future reliable communications. The HARQ scheme can be largely classified into two types. One is D. Chase, Code Combining: A maximum-likelihood decoding approach for combining an arbitrary number of noisy packets, IEEE Trans. on Commun., Vol. 33, pp. 593-607, May 1985, described in HARQ-CC (Chase Combining). The other is HARQ-IR (Increment Redundancy). In HARQ-CC, if the receiver detects an error through a cyclic redundancy check (CRC) while decoding the transmitted packet, the same packet with the same modulation and coding is retransmitted to the receiver. HARQ-IR, on the other hand, retransmits another packet such that the parity bits have been processed through puncturing or repetition to obtain coding gain. In order to perform HARQ, exchange of ACK (Acknowledgement) / NACK (Not-Acknowledgement) information on whether to retransmit is required.

In addition, AMC (Adaptive Modulation and Coding) is a technology for reliable communication. The base station determines a modulation and coding scheme (MCS) used for transmission by using a channel quality indicator (CQI) received from the terminal. In general, CQI is the index of an entity in the MCS table that represents the MCS. There are two ways for a UE to transmit a CQI. One is to send the CQI periodically, and the other is to send the CQI when requested by the base station.

3rd Generation Partnership Project (3GPP) long term evolution (LTE) is part of the Evolved-Universal Mobile Telecommunications System (E-UMTS) that uses Evolved-Universal Terrestrial Radio Access (E-UTRA). Adopt SC-FDMA in uplink. The resource allocation scheme of 3GPP LTE is based on dynamic scheduling. The downlink physical channel of 3GPP LTE can be divided into a physical downlink control channel (PDCCH) carrying resource allocation information and a physical downlink shared channel (PDSCH) carrying downlink data. The uplink physical channel includes a physical uplink control channel (PUCCH) carrying uplink control information and a physical uplink shared channel (PUSCH) carrying uplink data. In downlink transmission, the UE first receives a downlink grant on the PDCCH, and then receives downlink data on the PDSCH indicated by the downlink grant. In uplink transmission, the UE receives an uplink grant on the PDCCH and transmits uplink data on the PUSCH indicated by the uplink grant. Dynamic scheduling is a method for efficiently allocating resources, but the UE must first receive a downlink / uplink grant for data transmission and / or reception.

Signaling overhead is one of the main causes of lowering transmission efficiency and deteriorating frequency efficiency. In the dynamic scheduling method, in order to perform HARQ and CQI transmission, a plurality of signaling such as exchange of ACK / NACK information, exchange of transmission parameters for CQI, etc. are required in addition to reception of the PDCCH.

There is a need for a method that can reduce signaling overhead due to transmission of CQI while performing HARQ.

An object of the present invention is to provide a method for multiplexing and transmitting CQI and retransmission data.

In one aspect, a method for supporting a hybrid automatic repeat request (HARQ) in a wireless communication system, receiving an initial uplink grant on a downlink channel, uplink on an uplink channel using the initial uplink grant Transmitting data, receiving a retransmission request of the uplink data, determining at least one transmission parameter of a channel quality indicator (CQI) from the initial uplink grant, retransmitting the CQI of the uplink data Multiplexing with data, the resource amount for transmission of the CQI is determined based on the at least one transmission parameter, and transmitting the multiplexed data on the uplink channel.

A retransmission uplink grant for retransmission of the uplink data is received, and the retransmission data of the uplink data may be multiplexed using the retransmission uplink grant. The request for the CQI report may be included in the retransmission uplink grant. Retransmission data of the uplink data may be multiplexed using the initial uplink grant.

The downlink channel may be a physical downlink control channel (PDCCH), and the uplink channel may be a physical uplink shared channel (PUSCH).

At least one transmission parameter of the CQI may be related to a Modulation and Coding Scheme (MCS) of the CQI. At least one transmission parameter of the CQI may be determined such that the MCS of the CQI is the same as the MCS of the uplink data.

In another aspect, RF (Radio Frequency) unit for transmitting and receiving radio signals; And

A processor connected to the RF unit, the processor receiving an initial uplink grant on a downlink channel, transmitting uplink data on an uplink channel using the initial uplink grant, and transmitting the uplink data Receiving a retransmission request of the UE, determining at least one transmission parameter of a channel quality indicator (CQI) from the initial uplink grant, and multiplexing the CQI with retransmission data of the uplink data, wherein the amount of resources for transmission of the CQI Is determined based on the at least one transmission parameter, and is configured to transmit the multiplexed data on the uplink channel.

In performing HARQ, a method of transmitting the first transmission data and the CQI together is proposed. HARQ and AMC operation can be clarified and signaling overhead can be reduced.

The following techniques include 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. It can be used in various wireless communication systems. CDMA may be implemented with a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA may be implemented with wireless technologies such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented in a wireless technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) long term evolution (LTE) is part of an Evolved UMTS (E-UMTS) using E-UTRA, and employs OFDMA in downlink and SC-FDMA in uplink.

For clarity, the following description focuses on 3GPP LTE, but the technical spirit of the present invention is not limited thereto.

1 shows a wireless communication system.

Referring to FIG. 1, the wireless communication system 10 includes at least one base station 11 (BS). Each base station 11 provides a communication service for a particular geographic area (generally called a cell) 15a, 15b, 15c. The cell can in turn be divided into a number of regions (called sectors). The user equipment (UE) 12 may be fixed or mobile, and may include a mobile station (MS), a user terminal (UT), a subscriber station (SS), a wireless device, a personal digital assistant (PDA), It may be called other terms such as a wireless modem and a handheld device. The base station 11 generally refers to a fixed station communicating with the terminal 12 and may be called by other terms such as an evolved-NodeB (eNB), a base transceiver system (BTS), and an access point. Can be.

Hereinafter, downlink (DL) means communication from the base station to the terminal, and uplink (UL) means communication from the terminal to the base station. In downlink, a transmitter may be part of a base station, and a receiver may be part of a terminal. In uplink, a transmitter may be part of a terminal, and a receiver may be part of a base station.

The wireless communication system may support uplink and / or downlink Hybrid Automatic Repeat Request (HARQ). In addition, a channel quality indicator (CQI) may be used to support adaptive modulation and coding (AMC).

The CQI is intended to indicate the downlink channel state and is free on the CQI index and / or codebook that points to each entity in the Modulation and Coding Scheme (MCS) table that includes a plurality of entities consisting of a combination of coding rates and modulation schemes. It may include a PMI (Precoding Matrix Index) which is an index of a coding matrix. The CQI may indicate a channel state for all bands and / or a channel state for some bands of all bands.

2 shows a structure of a radio frame in 3GPP LTE. A radio frame consists of 10 subframes, and one subframe consists of two slots. The time taken for one subframe to be transmitted is called a transmission time interval (TTI). For example, one subframe may have a length of 1 ms, and one slot may have a length of 0.5 ms. One slot includes a plurality of SC-FDMA symbols (eg, 7 SC-FDMA symbols) in the time domain and includes a plurality of resource blocks (RBs) in the frequency domain. The SC-FDMA symbol is used to represent one symbol period since 3GPP LTE uses SC-FDMA in uplink, and may be referred to as an OFDMA symbol or a symbol period according to a system. The RB includes a plurality of consecutive subcarriers in one slot in resource allocation units.

The structure of the radio frame is only an example, and the number of subframes included in the radio frame or the number of slots included in the subframe and the number of SC-FDMA symbols included in the slot may be variously changed.

3 shows an example of a structure of a downlink subframe. The subframe includes two consecutive slots. Up to three OFDM symbols in the first slot in the downlink subframe are control regions to which a Physical Downlink Control Channel (PDCCH) is allocated, and the remaining OFDM symbols are a user region to which a Physical Downlink Shared Channel (PDSCH) is allocated. . The Physical Control Format Indicator Channel (PCFICH) transmitted in the first OFDM symbol of a subframe carries information about the number of OFDM symbols used for transmission of PDCCHs in the subframe.

The PDCCH carries a downlink grant informing of resource allocation of downlink transmission on the PDSCH. More specifically, the PDCCH is a higher layer control message such as a resource allocation and transmission format of a downlink shared channel (DL-SCH), paging information on a paging channel (PCH), system information on a DL-SCH, and a random access response transmitted on a PDSCH. Resource allocation, transmission power control command, and activation of voice over IP (VoIP). In addition, the PDCCH may carry an uplink grant informing the UE of resource allocation of uplink transmission. The PCFICH informs the UE of the number of OFDM symbols used for the PDCCHs and is transmitted every subframe. The Physical Hybrid ARQ Indicator Channel (PHICH) carries HARQ Acknowledgment (ACK) / Not-Acknowledgement (NACK) signals in response to uplink transmission.

4 shows a structure of an uplink subframe in 3GPP LTE.

Referring to FIG. 4, the uplink subframe is allocated a control region in which a physical uplink control channel (PUCCH) carrying uplink control information is allocated in a frequency domain and a physical uplink shared channel (PUSCH) carrying user data. It can be divided into data areas. In order to maintain a single carrier characteristic, one UE does not simultaneously transmit a PUCCH and a PUSCH.

PUCCH for one UE is allocated as an RB pair in a subframe, and RBs belonging to the RB pair occupy different subcarriers in each of two slots. This is said that the RB pair allocated to the PUCCH is frequency hopping at the slot boundary.

5 shows uplink HARQ and CQI transmission.

Referring to FIG. 5, the base station receiving the uplink data 100 on the PDSCH from the terminal transmits an ACK / NACK signal 101 for the uplink data 100 on the PHICH after a predetermined time elapses. The base station receiving the uplink data 100 may transmit the PHICH after 4 TTIs, but is not limited thereto. The ACK / NACK signal 101 becomes an ACK signal when the uplink data is successfully decoded, and becomes an NACK signal when the decoding of the uplink data fails. When the ACK / NACK signal 101 is determined as the NACK signal, the terminal retransmits the retransmission data 110 for the uplink data 100 to the base station. Retransmission may be achieved by receiving an ACK signal or up to a maximum number of retransmissions. When the ACK / NACK signal 111 for the retransmission data 110 is determined as the ACK signal, the terminal may transmit new uplink data 120 to the base station.

The transmission time or resource allocation of the ACK / NACK signal for uplink / downlink data may be dynamically informed by the base station through signaling, or may be previously determined according to the transmission time or resource allocation of uplink / downlink data. have.

The terminal may measure the downlink channel state and report the CQI to the base station periodically and / or aperiodically. Periodic CQI reporting refers to transmitting a CQI without a separate request from a base station according to a period or a predetermined period given to a base station, and aperiodic CQI reporting refers to transmitting a CQI in response to a request from a base station. CQI may be transmitted on PUCCH or PUSCH, but is always transmitted on PUSCH when multiplexed with data. The CQIs 180 and 184 transmitted alone may be transmitted on the PUCCH or the PUSCH. The CQI 182 transmitted together with the uplink data may be transmitted only on the PUSCH. The CQI transmitted on the PUSCH may be a periodic CQI or a non-subjective CQI. The base station can be used for downlink scheduling using the CQI.

Hereinafter, although HARQ is described in uplink transmission, those skilled in the art will be able to easily apply the technical idea of the present invention to HARQ in downlink transmission.

6 shows dynamic scheduling in uplink transmission.

Referring to FIG. 6, for uplink transmission, a UE first sends a scheduling request (SR) on a PUCCH to a base station. The SR requests the base station to allocate an uplink radio resource to the base station, which is a kind of advance information exchange for data exchange. In order to transmit uplink data to the base station, the terminal first requests radio resource allocation through the SR. The base station sends an uplink grant to the terminal on the PDCCH in response to the SR. The uplink grant includes allocation of uplink radio resources. The terminal transmits uplink data on the PUSCH through the allocated uplink radio resource.

7 is an exemplary diagram illustrating multiplexing of data and control information on a PUSCH. The PUSCH carries data and / or control information through resources allocated using an uplink grant.

Referring to FIG. 7, data bits a ₀ , a ₁ ,..., A _A-1 are given in the form of one transport block for every TTI. First, data bits a _0, a _1, ..., in _{a A-1 CRC (Cyclic Redundancy} Check) parity bits to _{p 0, p 1, ...,} p L-1 are added, CRC bit addition B ₀ , b ₁ ,..., B _B-1 are generated (200). Here, B = A + L. The relationship between a _k and b _k can be expressed as

CRC additional bits b ₀ , b ₁ ,..., B _B-1 are split into code block units, and CRC parity bits are added to the code block units (210). The bit sequence output after code block segmentation is called c _r0 , c _r1 , ..., c _{r (Kr-1)} . Here, when the total number of code blocks is C, r code block number, Kr is the number of bits for the code block number r.

The bit sequence for a given code block is channel coded 220. Encoded bits are represented by d ⁽ⁱ⁾ ₀ , d ⁽ⁱ⁾ ₁ , ..., d ⁽ⁱ⁾ _D-1 , where D is the number of encoded bits per output stream, i is the index of the encoder output bit stream .

The encoded bits are subjected to rate matching (230) and code block concatenation (240) to generate the data bit sequences f ₀ , f ₁ ,..., F _G-1 . . Here, G represents the total number of encoded bits used for transmission except for bits used for transmission of control information when control information is multiplexed on the PUSCH.

Meanwhile, control information may be multiplexed together with data. Data and control information may use different coding rates by assigning different numbers of coded symbols for their transmission. Hereinafter, the CQI is considered as control information.

CQI o ₀ , o ₁ , ..., o _O-1 (O is the number of bits of the CQI) channel coding is performed to generate the control information bit sequence q ₀ , q ₁ , ..., q _Q-1 (260). CQI may use independent channel coding other than data. For example, assuming that the (32, O) block code is used as the channel coding for the CQI, the basic sequence M _{i, n} is shown in the following table.

The intermediate sequences b ₀ , b ₁ , ..., b ₃₁ for CQI channel coding are generated as follows.

The control information bit sequence q ₀ , q ₁ , ..., q _Q-1 is generated by circularly repeating the intermediate sequences b ₀ , b ₁ , ..., b ₃₁ as follows.

The data bit sequence f ₀ , f ₁ , ..., f _G-1 and the control information bit sequence q ₀ , q ₁ , ..., q _{Q-1 generated as described above} are multiplexed sequence g ₀ , g ₁ , ..., multiplexed with g _H-1 (270). In the multiplexing, the control information bit sequences q ₀ , q ₁ , ..., q _Q-1 may be arranged _first , and then the data bit sequences f ₀ , f ₁ , ..., f _G-1 may be arranged. That is, when H = G + Q, [g ₀ , g ₁ , ..., g _H-1 ] = [q ₀ , q ₁ , ..., q _Q-1 , f ₀ , f ₁ , .. , f _G-1 ].

The multiplexed sequence g ₀ , g ₁ ,..., G _H-1 is mapped 280 to the modulation sequence h ₀ , h ₁ , ..., h _H'-1 . Here, h _i is a modulation symbol in constellation, H '= H / Q _m . Q _m is the number of bits per modulation symbol for the modulation scheme. For example, when using QPSK (Qaudrature Phase Shift Keying) as the modulation method, Q _m = 2.

Each modulation symbol of modulation sequence h ₀ , h ₁ , ..., h _H'-1 is mapped to a resource element for a PUSCH (290). A resource element is an allocation unit on a subframe defined by one SC-FDMA symbol (or OFDMA symbol) and one subcarrier. The modulation symbols are time-first mapped. 8 shows resource mapping on a PUSCH. One slot includes 7 SC-FDMA symbols, and a fourth SC-FDMA symbol in each slot is used for transmission of a reference signal. Therefore, the number of SC-FDMA symbols used for the PUSCH in one subframe is at most 12. The modulation sequences h ₀ , h ₁ , ..., h _H'-1 are mapped in the first subcarrier region first in the SC-FDMA symbol direction, and then in the second subcarrier region again in the SC-FDMA symbol direction. Since the front end of the modulation sequence h ₀ , h ₁ , ..., h _H'-1 corresponds to the CQI, the CQI is first mapped to resource elements in the preceding subcarrier region.

As described above, in order to transmit the CQI on the PUSCH, it is necessary to first determine the amount of resources required for the transmission of the CQI. The amount of resources is determined based on transmission parameters such as MCS used for CQI transmission. The transmission parameter for the CQI refers to a parameter used for transmission of the CQI, and includes various parameters for determining the amount of MCS and / or resources. If the amount of resources is represented by the number Q 'of modulation symbols for CQI, Q' may be determined as follows.

Where O is the number of bits of CQI, L is the number of CRC bits, Δ is the parameter, C is the total number of code blocks, K _r is the number of bits for code block number r, and M _sc is the number of subcarriers used for PUSCH transmission. , N _symb represents the number of SC-FDMA symbols used for PUSCH transmission. Transmission parameters for determining the Q 'may be at least one of C, K _r , M _sc , and N _symbs .

Now, when performing HARQ, it will be described how retransmission data and CQI are multiplexed and transmitted in PUSCH.

When performing HARQ, the CQI transmission may be transmitted by multiplexing on initial data, but may be transmitted by multiplexing on retransmission data. This may occur when the CQI transmission period matches the retransmission period in the periodic CQI report or when the response to the CQI transmission request matches the retransmission period in the aperiodic CQI report.

When a CQI is multiplexed onto retransmission data, it is a question of how to determine the transmission parameters (eg, MCS, etc.) for the CQI. This is a problem regarding how to determine the transmission parameters used for retransmission data and the multiplexed CQI. This is because, even when retransmission, if the base station to inform the UE of the transmission parameters for CQI transmission separately, it may act as signaling overhead.

When transmitting CQI at data retransmission, the CQI transmission parameter may be determined based on the transmission parameter used for initial data transmission. For example, the MCS used for initial data transmission is used for CQI transmission during retransmission.

9 is a flowchart illustrating a HARQ method according to an embodiment of the present invention.

Referring to FIG. 9, in step S510, the base station transmits an initial uplink grant on the PDCCH. The initial uplink grant includes radio resource allocation information for initial uplink data in HARQ. In step S520, the terminal transmits uplink data on the PUSCH indicated by the initial uplink grant.

In step S530, the base station that detects the decoding error of the uplink data transmits a NACK signal that is a retransmission request. The NACK signal may be transmitted on the PHICH.

In step S560, if the transmission subframe of the retransmission data coincides with the transmission subframe of the CQI, the terminal determines the transmission parameter of the CQI from the initial uplink grant. The transmission parameter is a parameter for determining the amount of radio resources required for transmission of the CQI and may be related to the MCS of the CQI. For example, when the amount of radio resources of the CQI is determined by Equation 4, at least one of C, K _r , M _sc , and N _symb corresponding to transmission parameters may be obtained from the initial uplink grant. have.

In step S570, the terminal multiplexes the CQI with retransmission data of the uplink data using the transmission parameter. In step S580, the multiplexed data is transmitted on the PUSCH.

In HARQ retransmission, when transmitting the retransmission data and the CQI together, by determining the MCS of the CQI based on the initial uplink grant, signaling signaling can be reduced because no separate signaling for the transmission parameters of the multiplexed CQI is required.

10 is a flowchart illustrating a HARQ method according to another embodiment of the present invention.

Referring to FIG. 10, in step S610, the base station transmits an initial uplink grant on the PDCCH. In step S620, the UE transmits uplink data on the PUSCH indicated by the initial uplink grant. In step S630, the base station that detects the decoding error of the uplink data transmits a NACK signal that is a retransmission request.

In step S650, the base station transmits the retransmission grant on the PDCCH. The retransmission grant includes radio resource allocation information for retransmission data for the uplink data.

In step S660, if the transmission subframe of the retransmission data coincides with the transmission subframe of the CQI, the terminal determines the transmission parameter of the CQI from the initial uplink grant. In step S670, the terminal multiplexes the CQI with the retransmission data of the uplink data using the transmission parameter. At this time, the retransmission data is multiplexed using the transmission parameter obtained from the retransmission grant, and the CQI is multiplexed using the transmission parameter obtained from the initial grant. In step S680, the multiplexed data is transmitted on the PUSCH.

11 is a flowchart illustrating a HARQ method according to another embodiment of the present invention.

Referring to FIG. 11, in step S700, the base station sets a periodic CQI. The terminal periodically transmits the CQI according to the period set by the base station. In step S710, the base station transmits an initial uplink grant on the PDCCH. The initial uplink grant includes radio resource allocation information for initial uplink data in HARQ. In step S720, the terminal transmits uplink data on the PUSCH indicated by the initial uplink grant.

In step S730, the terminal transmits the CQI in the CQI transmission period. In this case, if there is an available PUCCH resource, the CQI may be transmitted on the PUCCH. In S740, the base station that detects the decoding error of the uplink data transmits a NACK signal that is a retransmission request.

In step S760, if the transmission subframe of the retransmission data coincides with the transmission period of the CQI, the terminal determines the transmission parameter of the CQI from the initial uplink grant.

In step S770, the terminal multiplexes the CQI with retransmission data of the uplink data using the transmission parameter. In step S780, the multiplexed data is transmitted on the PUSCH.

12 is a flowchart illustrating a HARQ method according to another embodiment of the present invention.

Referring to FIG. 12, in step S810, the base station transmits an initial uplink grant on the PDCCH. In step S820, the UE transmits uplink data on the PUSCH indicated by the initial uplink grant. In step S830, the base station that detects the decoding error of the uplink data transmits a NACK signal that is a retransmission request.

In step S850, the base station transmits the retransmission grant and the CQI request on the PDCCH. The CQI request is a signal for the base station requesting the CQI transmission to the terminal as needed. The CQI request is transmitted on the PDCCH with the retransmission grant, but the CQI request may be transmitted to the UE through a separate message.

In step S860, the terminal determines the transmission parameter of the CQI from the initial uplink grant according to the CQI request of the base station. In step S870, the terminal multiplexes the CQI with the retransmission data of the uplink data using the transmission parameter. At this time, the retransmission data is multiplexed using the transmission parameter obtained from the retransmission grant, and the CQI is multiplexed using the transmission parameter obtained from the initial grant. In step S880, the multiplexed data is transmitted on the PUSCH.

Although the above embodiments disclose the CQI multiplexing in the first retransmission, the CQI transmission parameter may be obtained from the initial uplink grant even when the CQI is multiplexed and transmitted in the nth (n> 1) retransmission.

By using the transmission parameter used for the initial data transmission for the CQI transmission parameter, no separate signaling for the CQI transmission parameter is necessary.

In order to multiplex retransmission data and CQI on the PUSCH during HARQ, transmission parameters of the CQI may be obtained from other grants as well as the initial uplink grant. For example, a transmission parameter used for retransmission data multiplexed with the CQI may be a CQI transmission parameter. The same MCS as retransmission data is used for CQI transmission during retransmission. As another example, a transmission parameter used for a previous transmission may be used as a CQI transmission parameter. When the second retransmission data and the CQI are multiplexed during the second retransmission, the transmission parameter used for the first retransmission data is used as the CQI transmission parameter.

As mentioned above, aperiodic CQI is to transmit CQI in response to a request from a base station. The CQI request can generally be sent on the PDCCH. In this case, together with the CQI request, the transmission indicator for the CQI transmission parameter may be transmitted together. The CQI may be transmitted using the allocated resource (or transmission parameter) according to the transmission indicator, or the CQI may be transmitted using previously allocated resource (or transmission parameter).

13 is a block diagram illustrating an apparatus for wireless communication according to an embodiment of the present invention. The apparatus 50 for this wireless communication may be part of a terminal. The device 50 for wireless communication includes a processor 51, a memory 52, an RF unit 53, a display unit 54, a user interface unit, 55). The RF unit 53 is connected to the processor 51 and transmits and / or receives a radio signal. The memory 52 is connected with the processor 51 to store driving systems, applications, and general files. The display unit 54 displays various information of the terminal, and may use well-known elements such as liquid crystal display (LCD) and organic light emitting diodes (OLED). The user interface unit 55 may be a combination of a well-known user interface such as a keypad or a touch screen. The processor 51 supports HARQ and AMC. The processor 51 may configure a PUCCH or a PUSCH and perform multiplexing of data and CQI. Embodiments of the aforementioned method of performing HARQ may be performed by the processor 51.

The invention can be implemented in hardware, software or a combination thereof. In hardware implementation, an application specific integrated circuit (ASIC), a digital signal processing (DSP), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, and a microprocessor are designed to perform the above functions. , Other electronic units, or a combination thereof. In the software implementation, the module may be implemented as a module that performs the above-described function. The software may be stored in a memory unit and executed by a processor. The memory unit or processor may employ various means well known to those skilled in the art.

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

1 shows a wireless communication system.

2 shows a structure of a radio frame in 3GPP LTE.

3 shows an example of a structure of a downlink subframe.

4 shows a structure of an uplink subframe in 3GPP LTE.

5 shows uplink HARQ and CQI transmission.

6 shows dynamic scheduling in uplink transmission.

7 is an exemplary diagram illustrating multiplexing of data and control information on a PUSCH.

8 shows resource mapping on a PUSCH.

9 is a flowchart illustrating a HARQ method according to an embodiment of the present invention.

10 is a flowchart illustrating a HARQ method according to another embodiment of the present invention.

11 is a flowchart illustrating a HARQ method according to another embodiment of the present invention.

12 is a flowchart illustrating a HARQ method according to another embodiment of the present invention.

13 is a block diagram illustrating an apparatus for wireless communication according to an embodiment of the present invention.

Claims (15)

In a method of supporting a hybrid automatic repeat request (HARQ) in a wireless communication system, Receiving an initial uplink grant on a downlink channel; Transmitting uplink data on an uplink channel using the initial uplink grant; Receiving a request for retransmission of the uplink data; Determining at least one transmission parameter of a channel quality indicator (CQI) from the initial uplink grant; Multiplexing the CQI with retransmission data of the uplink data, wherein a resource amount for transmission of the CQI is determined based on the at least one transmission parameter; And Transmitting the multiplexed data on the uplink channel. The method of claim 1, Receiving a retransmission uplink grant for retransmission of the uplink data, wherein the retransmission data of the uplink data is multiplexed using the retransmission uplink grant. The method of claim 2, The request for the CQI report is included in the retransmission uplink grant. The method of claim 1, The retransmission data of the uplink data is multiplexed using the initial uplink grant. The method of claim 1, The downlink channel is characterized in that the physical downlink control channel (PDCCH). The method of claim 1, The uplink channel is characterized in that the PUSCH (Physical Uplink Shared Channel). The method of claim 1, At least one transmission parameter of the CQI is related to a Modulation and Coding Scheme (MCS) of the CQI. The method of claim 1, At least one transmission parameter of the CQI is determined such that the MCS of the CQI is the same as the MCS of the uplink data. The method of claim 1, Receiving a CQI transmission period for periodic CQI reporting. RF (Radio Frequency) unit for transmitting and receiving a wireless signal; And Including a processor connected to the RF unit, wherein the processor Receive an initial uplink grant on a downlink channel, Transmits uplink data on an uplink channel using the initial uplink grant, Receiving a request for retransmission of the uplink data, Determine at least one transmission parameter of a channel quality indicator (CQI) from the initial uplink grant, Multiplexing the CQI with retransmission data of the uplink data, wherein a resource amount for transmission of the CQI is determined based on the at least one transmission parameter, and And transmit the multiplexed data over the uplink channel. The method of claim 10, And the processor is configured to receive a retransmission uplink grant for retransmission of the uplink data, wherein the retransmission data of the uplink data is multiplexed using the retransmission uplink grant. The method of claim 11, And a request for the CQI report is included in the retransmission uplink grant. The method of claim 10, The retransmission data of the uplink data is multiplexed using the initial uplink grant. The method of claim 10, At least one transmission parameter of the CQI is related to a Modulation and Coding Scheme (MCS) of the CQI. The method of claim 10, And at least one transmission parameter of the CQI is determined such that the MCS of the CQI is the same as the MCS of the uplink data.

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