KR20170013003A - The Apparatus and Method for performing of HARQ procedure in a wireless communication system - Google Patents

Abstract

The present specification relates to a HARQ operation method of a terminal in a wireless communication system. At this time, the HARQ operation method may include receiving uplink resource allocation information from the base station, transmitting data based on the received uplink resource allocation information, and receiving feedback information on data transmission from the base station have. In this case, if the autonomous gap is set at the first time point at which the feedback information is received, the terminal may not receive the feedback information.

Description

[0001] The present invention relates to a method and apparatus for performing an HARQ operation in a wireless communication system,

The present disclosure relates to wireless communication systems, and more particularly, to a method and apparatus for performing HARQ operations in a wireless communication system.

As a wireless communication system, an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) is also called an LTE (Long Term Evolution) system. For details of the technical specifications for the wireless communication system, refer to " 3rd Generation Partnership Project (Technical Specification Group Radio Access Network) ".

Referring to FIG. 1, an E-UTRAN includes an Access Gateway (UE) located at the end of a User Equipment (UE), a Node B (eNB), and an E-UTRAN, Hereinafter AG). Typically, a base station may simultaneously transmit multiple data streams for broadcast services, multicast services, and / or unicast services. An interface for transmitting user traffic or control traffic may be used between the base stations. The AG may be divided into a part for handling user traffic and a part for processing control traffic. At this time, a new interface between the AG for processing new user traffic and the AG for processing control traffic can be communicated with each other. Also, the AG manages the mobility of the UE in a TA (Tracking Area) unit, and the TA is composed of a plurality of cells. If the terminal moves from one TA to another TA, it informs AG that the TA where it is located has changed. The CN (Core Network) may be configured as a network node for user registration of AG and UE, and an interface for distinguishing E-UTRAN and CN may be used. Hereinafter, a method of performing HARQ operations on a mobile station based on E-UTRAN will be described.

The present disclosure has an object to provide a method and apparatus for performing HARQ operations in a wireless communication system.

It is an object of the present invention to provide a method for improving the efficiency of radio resources by preventing unnecessary transmission by controlling an HARQ operation based on an autonomous gap in a wireless communication system.

A method of operating a Hybrid Automatic Repeat request (HARQ) of a mobile station in a wireless communication system, the method comprising: receiving uplink resource allocation information from a base station; And receiving feedback information on data transmission from the base station. In this case, if the autonomous gap is set at the first time point at which the feedback information is received, the terminal may not receive the feedback information.

In addition, according to an embodiment of the present invention, a terminal device performing a Hybrid Automatic Repeat request (HARQ) operation in a wireless communication system includes a receiving module for receiving information from an external device, a transmitting module for transmitting information to an external device, And a processor for controlling the module and the transmitting module. At this time, the processor receives the uplink resource allocation information from the base station using the reception module, transmits data through the transmission module based on the received uplink resource allocation information, and transmits data from the base station to the base station Feedback information can be received. In this case, if the autonomous gap is set at the first time point at which the feedback information is received, the terminal may not receive the feedback information.

In addition, the following aspects can be commonly applied to the method and the terminal apparatus for performing the HARQ operation in the wireless communication system.

According to an embodiment of the present invention, when the feedback information is not received due to the set autonomous gap, the UE can perform the determination of the acknowledgment or the negative response to the feedback information. At this time, the UE may set the feedback information as an acknowledgment and not retransmit the data.

Also, according to an embodiment of the present disclosure, retransmission of the feedback information may not be performed even if the autonomous gap is released at a second point in time after the first point in time.

The present specification can provide a method and apparatus for performing HARQ operations in a wireless communication system.

The present specification can provide a method for improving the efficiency of radio resources by preventing unnecessary transmission by controlling an HARQ operation based on an autonomous gap in a wireless communication system.

The effects obtainable in the present specification are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

1 is a diagram conceptually showing a network structure of an E-UTRAN according to an embodiment of the present invention.
2 is a conceptual diagram illustrating a network structure of an E-UTRAN according to an embodiment of the present invention.
3 is a diagram illustrating a wireless interface protocol structure between a terminal and an E-UTRAN based on the 3GPP RAN specification according to an embodiment of the present invention.
4 is a diagram illustrating a wireless interface protocol structure between a terminal based on the 3GPP RAN specification and an E-UTRAN according to an embodiment of the present invention.
5 is a diagram illustrating an example of a physical channel structure used in an E-UTRAN system according to an embodiment of the present invention.
6 is a diagram illustrating a method of retransmitting data based on HARQ operations according to an embodiment of the present invention.
7 is a diagram illustrating a method of retransmitting data based on HARQ operations according to an embodiment of the present invention.
8 is a diagram illustrating a method of retransmitting data based on HARQ operations according to an embodiment of the present invention.
9 is a diagram illustrating a method of performing an HARQ operation when a measurement gap and an HARQ conflict in accordance with an embodiment of the present invention.
10 is a diagram illustrating a method of performing an HARQ operation when an autonomous gap and an HARQ conflict in accordance with an embodiment of the present invention.
11 is a diagram illustrating a method of performing an HARQ operation when an autonomous gap and an HARQ conflict in accordance with an embodiment of the present invention.
12 is a flowchart illustrating a method of performing data transmission according to an embodiment of the present invention.
13 is a flowchart illustrating a method of performing data transmission based on autonomous gaps in accordance with one embodiment of the present disclosure.
FIG. 14 is a flowchart illustrating a method of performing HARQ operation according to an embodiment of the present invention. Referring to FIG.
15 is a block diagram of a terminal device according to an embodiment of the present invention.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without these specific details.

The following embodiments are a combination of elements and features of the present invention in a predetermined form. Each component or characteristic may be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. In addition, some of the elements and / or features may be combined to form an embodiment of the present invention. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments.

The specific terminology used in the following description is provided to aid understanding of the present invention, and the use of such specific terminology may be changed into other forms without departing from the technical idea of the present invention.

In some instances, well-known structures and devices are omitted or shown in block diagram form around the core functions of each structure and device in order to avoid obscuring the concepts of the present invention. In the following description, the same components are denoted by the same reference numerals throughout the specification.

Embodiments of the present invention may be supported by standard documents disclosed in at least one of IEEE 802 systems, 3GPP systems, 3GPP LTE and LTE-Advanced (LTE-Advanced) systems and 3GPP2 systems, which are wireless access systems. That is, the steps or portions of the embodiments of the present invention that are not described in order to clearly illustrate the technical idea of the present invention can be supported by the documents. In addition, all terms disclosed in this document may be described by the standard document.

The following description will be made on the assumption that the present invention is applicable to a CDMA system such as Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), and Single Carrier Frequency Division Multiple Access And can be used in various radio access systems. CDMA may be implemented in radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. The TDMA may be implemented in a wireless 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 in wireless technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and Evolved UTRA (E-UTRA).

Furthermore, the terms first and / or second, etc. may be used herein to describe various components, but the components should not be limited by the terms. The terms may be named for the purpose of distinguishing one element from another, for example, without departing from the scope of the rights under the concept of the present disclosure, the first element being referred to as the second element, , The second component may also be referred to as a first component.

Also, throughout the specification, when an element is referred to as " including " an element, it means that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. And the description "... unit", "… Quot; and " part " refer to a unit for processing at least one function or operation, which may be implemented as a combination of hardware and / or software.

2 is a conceptual diagram illustrating a network structure of an evolved universal terrestrial radio access network (E-UTRAN). Especially, the E-UTRAN system is an evolved system in the existing UTRAN system. The E-UTRAN is composed of cells (eNBs), and the cells are connected via the X2 interface. The cell is connected to the terminal through the air interface, and is connected to the EPC (Evolved Packet Core) through the S1 interface. EPC is composed of MME (Mobility Management Entity), S-GW (Serving-Gateway) and PDNGW (Packet Data Network-Gateway). The MME has information on the access information of the terminal or the capability of the terminal, and this information is mainly used for managing the mobility of the terminal. The S-GW is a gateway having an E-UTRAN as an end point, and the PDN-GW is a gateway having a PDN (Packet Data Network) as an end point.

Meanwhile, the 3GPP standard document TS 36.304 classifies the services provided by the E-UTRAN to the terminal into the following three types as shown in Table 1 below.

Also, in 3GPP standard document TS 36.304, cell types are classified as shown in Table 2 below with respect to a service type in which cells are provided to UEs.

Here, the acceptable cell is a cell which is not barred for the UE and satisfies the cell selection criterion of the UE, and is a cell that can receive only limited services such as emergency call and ETWS. Also, a suitable cell satisfies the condition of the acceptable cell and satisfies the additional conditions at the same time. As an additional condition, this cell should belong to a PLMN that the corresponding terminal can access, and should not be inhibited from performing the TA update procedure of the terminal. If the corresponding cell is a closed subscriber group (CSG) cell, the terminal must be a cell capable of being connected as a CSG member.

For reference, the 3GPP standard document TS 25.304 defines a service and a cell type provided by a Universal Terrestrial Radio Access Network (UTRAN) to a terminal, and a Global System for Mobile communication (GSM) is provided to a terminal in the 3GPP standard document TS 43.022 Service and cell types are defined. In particular, the limited services provided by UTRAN and GSM support only emergency calls except ETWS.

3 is a diagram showing a structure of a control plane of a radio interface protocol between a terminal based on the 3GPP radio access network standard and the E-UTRAN, FIG. 4 is a diagram showing a structure of a control plane based on the 3GPP radio access network standard U-Plane (User-Plane) structure of a radio interface protocol between a terminal and an E-UTRAN. In particular, the wireless interface protocol consists of a physical layer, a data link layer, and a network layer vertically, and horizontally includes a user plane for data information transmission and a control plane And a control plane for signal transmission.

The protocol layers of FIGS. 3 and 4 are based on an Open System Interconnection (OSI) reference model widely known in communication systems. The lower three layers are referred to as L1 (first layer), L2 ), And L3 (third layer). The control plane is a path through which control messages used by the UE and the network to manage calls are transmitted. The user plane means a path through which data generated in the application layer, for example, voice data or Internet packet data, is transmitted. Hereinafter, the layers of the control plane and the user plane of the wireless protocol will be described.

The physical layer as the first layer provides an information transfer service to an upper layer using a physical channel. The physical layer is connected to the upper layer of Medium Access Control (MAC) layer through a transport channel. Data is transferred between the MAC layer and the physical layer through the transport channel. Data is transferred between the transmitting side and the receiving side physical layer through the physical channel. The physical channel is modulated by an Orthogonal Frequency Division Multiplexing (OFDM) scheme, and uses time and frequency as radio resources.

The MAC layer of the second layer provides a service to a radio link control (RLC) layer, which is an upper layer, through a logical channel. The RLC layer of the second layer supports reliable data transmission. The function of the RLC layer may be implemented as a function block inside the MAC. In this case, the RLC layer may not exist. The Packet Data Convergence Protocol (PDCP) layer of the second layer performs a header compression function to reduce unnecessary control information for efficient transmission in an air interface having a narrow bandwidth when transmitting IP packets such as IPv4 or IPv6 . A Radio Resource Control (RRC) layer located at the bottom of the third layer is defined only on the control plane and includes a configuration, reconfiguration, and release of radio bearers (RBs) And controls the logical channels, the transport channels, and the physical channels. The radio bearer means a service provided by the second layer for data transmission between the UE and the EUTRAN. To this end, the RRC layer exchanges RRC messages between the UE and the network.

Hereinafter, the RRC state of the UE and the RRC connection method will be described. The RRC state refers to whether or not the RRC of the UE is a logical connection with the RRC of the E-UTRAN. If the RRC is connected, the RRC connection state (RRC_CONNECTED) is established. If not, the RRC idle state (RRC_IDLE) .

Since the E-UTRAN can grasp the presence of the UE in the RRC-connected state on a cell-by-cell basis, the E-UTRAN can effectively control the UE. On the other hand, the E-UTRAN can not grasp the RRC idle terminal in the cell unit, and the CN manages the TA unit, which is a larger area unit than the cell. That is, in order for the UE in the RRC idle state to receive services such as voice or data from the cell, the UE must transition to the RRC connected state. In particular, when the user first turns on the power of the UE, the UE first searches for an appropriate cell and stays in the RRC idle state in the cell. The UE which has stayed in the RRC idle state performs the RRC connection establishment process with the RRC of the E-UTRAN only when it is necessary to establish the RRC connection, and transits to the RRC connection state. Here, the case where the RRC connection needs to be established means that uplink data transmission is required due to a user's call attempt or the like, or when a paging message is received from the E-UTRAN, a response message should be transmitted.

As described above, since the cell selection procedure is performed in a state in which the UE does not currently determine the cell in which the RRC is in the idle state, it is most important to select the cell as quickly as possible. Therefore, even if the cell is not a cell providing the best radio signal quality to the UE, that is, it is an acceptable cell but not a suitable cell, it can be selected in the cell selection procedure of the UE have. On the other hand, if the UE can not perform normal communication due to deteriorated quality of the radio channel or mismatch between the UE and the network, the UE determines that the current communication link is faulty and can start the RRC connection re-establishment procedure.

In the 3GPP standard document TS 36.331, if the UE determines that there is a serious problem with the downlink communication link quality based on the result of radio quality measurement of the physical layer of the UE as an example in which the normal communication can not be performed, Random Access procedure is continuously failed or the uplink data transmission in the RLC sublayer continues to fail and it is determined that there is a serious problem in the uplink transmission, the handover has failed or the message received by the terminal is subjected to an integrity check integrity check, and so on.

Hereinafter, a method for recovering uplink resources after an uplink synchronization state is switched to an asynchronous state based on a specific condition in an RRC connected state and the uplink resources are released will be described later.

5 is a diagram illustrating an example of a physical channel structure used in an E-UMTS system.

The physical channel is composed of several subframes on the time axis and several subcarriers on the frequency axis. Here, one subframe consists of a plurality of symbols on the time axis. One subframe is composed of a plurality of resource blocks, and one resource block is composed of a plurality of symbols and a plurality of subcarriers. In the E-UMTS system currently under discussion, a radio frame of 10 ms is used and one radio frame is composed of 10 subframes. Also, one subframe consists of two consecutive slots. The length of one slot is 0.5 ms, and the TTI (Transmission Time Interval), which is a unit time in which data is transmitted, is 1 ms. Referring to FIG. 5, each subframe may use specific subcarriers of specific OFDM symbols (e.g., first symbol) of a corresponding subframe for a physical downlink control channel (PDCCH), i.e., an L1 / have. FIG. 5 shows an L1 / L2 control information transmission region (PDCCH) 501 and a data transmission region (PDSCH) 502.

The BS and the UE generally transmit and receive data through the PDSCH 502, which is a physical channel, using a DL-SCH, which is mostly a transport channel, except for a specific control signal or specific service data. Data of the PDSCH 502 is transmitted to a terminal (one or a plurality of terminals), and information on how the terminals receive and decode the PDSCH data is included in the PDCCH 501 and transmitted.

For example, when a specific PDCCH 501 is CRC masked with an RNTI (Radio Network Temporary Identity) A, and a radio resource (for example, a frequency location) B and transmission format information C , Transport block size, modulation, coding information, and the like) is transmitted through a specific subframe. In this case, one or more UEs in the corresponding cell monitor the PDCCH 501 using RNTI information it has, and if there is more than one UE having an A RNTI, the UEs receive the PDCCH 501, And receives the PDSCH 502 indicated by B and C through the information of one PDCCH 501. [

6, 7, and 8 are diagrams illustrating a method for retransmitting data based on HARQ operations in accordance with one embodiment of the present disclosure.

Referring to FIG. 6, the UE can receive UL-grant information through the PDCCH. At this time, UL-grant may be uplink resource allocation information. The UE can perform resource allocation for data to be transmitted based on the received UL-grant and transmit uplink data. Thereafter, the UE can confirm whether or not the data transmitted through the uplink is correctly received, and perform data retransmission. For example, if resource allocation is set by the PDCCH received by the UE, a HART RTT timer can be started. At this time, as an example, the HART RTT timer may be 8 ms. At this time, if the HART RTT timer expires, HARQ feedback information may be transmitted to the UE. In this case, for example, the base station can transmit HARQ feedback information to the UE through PHICH (Physical Hybrid-ARQ indicator channel) when the HART RTT timer expires. At this time, the HARQ feedback information may be an acknowledgment (ACK) or a negative acknowledgment (NACK). In this case, for example, if the HARQ feedback information is an acknowledgment, the UE may not retransmit the data. That is, if the data transmitted by the terminal indicate that it has been correctly received, the terminal may not retransmit the data. On the other hand, if the HARQ feedback information is a negative response, the UE can retransmit the data. That is, since the data transmitted by the terminal may not be correctly received, the terminal can retransmit the data.

More specifically, referring to FIG. 8, the terminal may be the transmitting side and the base station may be the receiving side. In this case, for example, the HARQ feedback information is described assuming an uplink state received from the base station, but the same can be applied to the downlink.

For example, the base station can transmit uplink scheduling information (UL-Grant) through the PDCCH in order to allow the UE to transmit data in the HARQ scheme (S810). In this case, Information on the terminal identifier may be included. In this case, for example, the information on the terminal identifier may include a C-RNTI or a semi-persistent scheduling C-RNTI, a resource block assignment, a modulation / coding rate and a redundancy version, New Data Indicator). At this time, the UE monitors the PDCCH for each TTI (Transmission Time Interval) to confirm uplink information allocated to the UE. When the UE receives the uplink information allocated to the UE through the PDCCH monitoring, the UE can transmit the data on the PUSCH based on the uplink information (S802). In this case, for example, data to be transmitted may be transmitted in units of MAC PDU (Medium Access Control Packet Data Unit). As described above, the UE that has performed the uplink transmission through the PUSCH can wait for receiving the HARQ feedback information through the PHICH from the base station. In this case, for example, the terminal may transmit the first data to the base station. Then, the UE can receive a negative acknowledgment (NACK) as HARQ feedback information for the first data. (S803) At this time, the UE can retransmit the first data in the retransmission TTI of the first data (S804 ). On the other hand, when the HARQ ACK is received from the base station (not shown), the UE can stop HARQ retransmission for the first data. For example, the UE counts the number of transmissions (CURRENT_TX_NB) every time it performs one data transmission in the HARQ scheme, and when the number of transmissions reaches the maximum number of transmissions (CURRENT_TX_NB) set in the upper layer, the HARQ buffer It is possible to discard the stored MAC PDU. After the UE retransmits the first data through the retransmission TTI, the UE can receive the HARQ feedback information again. At this time, the UE can receive an ACK for the first data (S405). After that, the UE can receive a new UL-grant on the PDCCH from the Node B. (S806) The UE can confirm whether the data to be transmitted this time is an initial transmission MAC PDU or a previous MAC PDU retransmission through an NDI (New Data Indicator) field received via the PDCCH. In this case, for example, the NDI field is a 1-bit field and can be toggled to 0 -> 1 -> 0 -> 1 -> ... every time a new MAC PDU is transmitted. At this time, the retransmission has the same value as the initial transmission. That is, the UE can check whether the MAC PDU is retransmitted by comparing whether the NDI field is equal to the previously transmitted value. In this case, for example, when the value of NDI = 0 is toggled to NDI = 1, the UE can confirm that the corresponding transmission indicates a new transmission. At this time, the terminal can transmit the second data, which is new data, through the PUSCH (S807)

9 is a diagram illustrating a method of performing an HARQ operation when a measurement gap and an HARQ conflict in accordance with an embodiment of the present invention.

In a LTE system, a base station can set a measurement operation to a terminal requiring heterogeneous measurement in order to support mobility. In the measurement gap where the UE performs heterogeneous measurement, the communication between the BS and the UE is generally disconnected. Here, the "measurement gap" may include an intra-frequency measurement, an inter-frequency measurement, and an inter-RAT mobility measurement performed by the UE. At this time, the measurement gap is determined according to the setting of the base station, and the measurement gap operation is performed for each predetermined interval, so that the terminal stops transmission to the base station for 6 ms or 7 ms on the uplink, Lt; / RTI > At this time, the UE can not receive the HARQ feedback information during the measurement gap. That is, when the measurement gap and the HARQ feedback collide, the HARQ operation can not be performed.

In this case, for example, referring to FIG. 9, when the UE receives an UL grant from the BS, the UE can generate an MAC PDU corresponding to the received UL-grant and perform initial transmission. At this time, the MAC PDU A may be transmitted (S901). Then, the MS can receive HARQ feedback information corresponding to the MAC PDU A transmission from the BS at a predetermined time (S902). Generally, in the LTE system, the HARQ operation operates in a synchronous manner, so that HARQ feedback information for the corresponding UL transmission is received at a predetermined timing. In this case, for example, if the UE receives the HARQ feedback information for the negative response, the UE can retransmit the MAC PDU A (S903). Here, the HARQ operation may be performed in a non-adaptive manner. In this case, for example, the UE may transmit the MAC PDU retransmission in the same manner through the same resource as the previous transmission without receiving a separate UL-grant. In this case, for example, if heterogeneous measurement is required in the system, the base station can set a measurement gap of a predetermined period in the terminal, and the terminal can perform measurement of heterogeneous frequency, measurement of the same frequency or measurement of heterogeneous radio system mobility Operation can be performed. At this time, "heterogeneous frequency measurement" represents a measurement operation at a frequency different from that of the serving cell at the downlink carrier frequency, and "homogeneous frequency measurement" may represent a measurement operation at the downlink carrier frequency of the serving cell. have. In addition, the "heterogeneous wireless system mobility measurement" can be used to measure heterogeneous radio systems of UTRA (Universal Terrestrial Radio Access) frequency, heterogeneous radio system measurement of GERAN (GSM / EDGE Radio Access Network) frequency and CDMA2000 High Rate Packet Data (HRPD) And heterogeneous radio system measurements of CDMA2000 1x Radio Transmission Technology (1xRTT) frequencies. The base station can set the above-described measurement gap through a radio resource control (RRC) layer signal to the mobile station. In addition, the measurement operation described above can be managed by the RRC layer module of the terminal. In this case, for example, the UE may overlap the measurement gap with the time when the HARQ feedback information is received. At this time, since the UE can not receive an instruction from the Node B, the UE may not be able to perform the HARQ operation thereafter. In this case, for example, the UE can determine an acknowledgment and a negative response to the HARQ feedback information. In this case, for example, if the UE fails to receive the HARQ feedback information due to the measurement gap, the UE can determine the HARQ feedback information as an acknowledgment. That is, the UE determines that transmission to the MAC PDU has been correctly performed, and may not retransmit the data. That is, since the UE can not receive the HARQ feedback information, it can stop the data retransmission. Thus, the stability of the system can be improved. In addition, for example, the UE may determine a positive response and perform a new transmission by receiving a new UL-grant and receiving a resource allocation for canceled retransmission.

10 and 11 are diagrams illustrating a method of performing an HARQ operation when an autonomous gap and an HARQ conflict in accordance with an embodiment of the present invention.

The UE can perform measurement reporting to the base station under certain conditions. At this time, for example, the UE performs a measurement result report based on comparison values and absolute values with surrounding cells based on reference signal received power (RSRP), reference signals received quality (RSRQ), received signal strength indicator . In this case, for example, the base station can determine whether handover is necessary using the received information. At this time, if a handover is required, it is determined whether system information including an ID of neighboring cells is present, and a target cell capable of handover can be set.

At this time, for example, even if the terminal performs measurement based on the above-described measurement gap, system information about neighboring cells may not be known. That is, the terminal may not be able to obtain information on CGI (Cell Global Identifier). Therefore, the UE needs to acquire information on the MIB (Master Information Block) and the SIB (System Information Block) for the neighboring cells in order to acquire the CGI information. In this case, for example, the terminal can receive the above-described information after setting DRX (discontinuous reception) as an idle period in order to acquire the above-described information. At this time, the terminal may not be able to perform communication with the serving base station.

In another example, when the UE does not know the system information including the ID of the neighboring cell, the UE needs to identify and report the CGI information at the request of the base station. At this time, the terminal can set an autonomous gap. That is, the UE can receive MIBs and SIBs for neighboring cells without performing communication during the autonomous gap. In this case, for example, when the UE sets an autonomous gap to report CGI information, the UE can operate regardless of whether DRX is used or SCell is set. In addition, for example, the terminal sets an autonomous gap only when the "si-RequestForHO" is instructed to the upper layer based on the message and the "si-RequestForHO" is set to "true" can do. In this case, for example, if "si-RequestForHO" is set to "false", the terminal may not set an autonomous gap. In this case, for example, the UE may be able to acquire MIB, SIB information, etc. for the neighbor base station after setting the DRX as described above.

 That is, the UE can set an autonomous gap and acquire system information about neighboring cells only when indicated by an upper layer message under a certain condition.

That is, the UE may set an autonomous gap to acquire information such as MIB and SIB for neighbor cells, and may not perform communication with the serving cell for a predetermined time. In this case, for example, an autonomous gap may be set at a time when the UE receives the HARQ feedback information. More specifically, as described above, the UE can receive UL-grant information through the PDCCH and transmit data based on the received UL-grant information. Thereafter, the UE can receive HARQ feedback information as feedback information on the transmitted data. At this time, an autonomous gap is set at a time point when the UE receives the HARQ feedback, so that the UE may not be able to communicate with the serving cell. That is, the UE may not receive the HARQ feedback. In this case, if the autonomous gap and HARQ feedback conflict, for example, the UE can perform HARQ retransmission. That is, since the UE has to set an autonomous gap to perform unnecessary HARQ retransmission, radio resources may be wasted.

Therefore, referring to FIG. 11, if the UE has not set up an autonomous gap and has not received HARQ feedback information, the UE needs to be able to determine an acknowledgment or negative response to the HARQ feedback information. At this time, the UE determines that the HARQ feedback information is an acknowledgment and does not retransmit the uplink data. That is, if the autonomous gap is set and it is not known whether the data has been properly retransmitted, the UE can avoid unnecessary HARQ retransmission and process the acknowledgment to prevent radio resource waste. In addition, for example, when retransmission of data is required, the UE can newly receive UL-grant through the PDCCH and perform data transmission, as described above.

12 and 13 are flowcharts illustrating a method of performing data transmission based on autonomous gaps in accordance with one embodiment of the present disclosure.

The UE monitors the PDCCH and can perform uplink data transmission using UL-grant information. At this time, if the UE monitors the PDCCH and acquires the UL-Grant information, the UE can check the NDI (New Data Indicator) to check whether the transmission is for the previous data. That is, the terminal transmits new data when the NDI is toggled, and can retransmit previous data if it is not toggled, which is described above.

In addition, if the UE monitors the PDCCH and fails to receive the UL-grant information, the UE can check whether a scheduled PUSCH exists. At this time, if the scheduled PUSCH does not exist, the UE may not perform data transmission. However, if there is a PUSCH scheduled in the past, the UE can perform uplink transmission through the PUSCH. At this time, as described above, the UE can confirm whether the data is correctly transmitted through the HARQ process. For example, if the UE receives a negative response (NACK) as HARQ feedback information, it can retransmit the data. In addition, if the UE receives the acknowledgment (ACK) as the HARQ feedback information, the UE can terminate the transmission without retransmitting the data. In addition, for example, if the UE does not receive the HARQ feedback information because the measurement gap is set, the UE can determine the positive and negative responses to the HARQ feedback information. At this time, the UE determines that the HARQ feedback information is an acknowledgment and does not perform retransmission.

Also, referring to FIG. 13, the UE can set an autonomous gap to acquire information on MIBs, SIBs, etc. for neighbor cells. At this time, as described above, if the UE does not receive the HARQ feedback information because the autonomous gap is set, the UE can determine the positive and negative responses to the HARQ feedback information. At this time, the UE determines that the HARQ feedback information is an acknowledgment and does not perform retransmission, as described above.

FIG. 14 is a flowchart illustrating a method of performing HARQ operation according to an embodiment of the present invention. Referring to FIG.

The UE can receive uplink resource allocation information from the Node B (S1410). As described above with reference to FIGS. 6 to 13, the UE can receive the UL-grant information by monitoring the PDCCH. Next, the UE can transmit data based on the received uplink resource allocation information. (S1420) At this time, as described above with reference to FIGS. 6 to 13, the UE can transmit uplink data through the PUSCH. Next, the UE can receive feedback information on data transmission from the Node B (S1430). At this time, the UE can receive the HARQ feedback information based on the HARQ process, as described above with reference to FIGS. At this time, if the HARQ feedback information is an acknowledgment, the UE may not retransmit data. In addition, if the HARQ feedback information is a negative acknowledgment, the UE can retransmit data.

Next, the UE can determine whether an autonomous gap is set at a first time point when the feedback information is received (S1440). In this case, if the autonomous gap is not set at the first time, It is possible to determine whether to retransmit the data based on the information. That is, the UE can receive HARQ feedback information and perform data retransmission if the UE receives a negative response. However, if the autonomous gap is set at the first time point of receiving the HARQ feedback information, the UE determines that the feedback information is an acknowledgment and does not perform the data retransmission (S1460). In this case, As described above, when the autonomous gap is set at the first time point of receiving the HARQ feedback information, the UE can not perform the communication and thus can not receive the HARQ feedback information. Accordingly, the UE can determine whether the HARQ feedback information is positive or negative. The UE determines that the HARQ feedback information is an acknowledgment and does not perform retransmission on the data, which is described above.

15 is a block diagram of a terminal device according to an embodiment of the present invention.

The terminal device can transmit data. The terminal device 100 includes a transmission module 110 for transmitting a radio signal, a reception module 130 for receiving a radio signal, and a processor 120 for controlling the transmission module 110 and the reception module 130 can do. At this time, the terminal 100 can perform communication with an external device using the transmission module 110 and the reception module 130. [ At this time, the external device may be another terminal device. The external device may be a base station, a core network, or the like. That is, the external device may be a device that communicates with the terminal device 100 to exchange data or information, and is not limited to the above-described embodiment. The terminal device 100 can transmit and receive data and / or information using the transmission module 110 and the reception module 130. [ That is, the terminal device 100 can exchange information with an external device by performing communication using the transmission module 110 and the reception module 130. [

In this case, for example, the processor 120 may receive the uplink resource allocation information from the base station using the reception module 130. [ In addition, the processor 120 may transmit data to the base station using the transmission module 110 based on the received uplink resource allocation information. In addition, the processor 120 may receive feedback information on data transmission from the base station using the receiving module 130. [ In this case, for example, if the autonomous gap is set at the first time point at which the feedback information is received, the terminal may not receive the feedback information. In addition, for example, when feedback information is not received due to the set autonomous gap, the processor 120 may perform a determination of an affirmative response or a negative response to the feedback information. At this time, the processor 120 sets the feedback information as an acknowledgment and does not perform the retransmission for the data, thereby preventing waste of radio resources in the state where the autonomous gap is set. Also, for example, the processor 120 may not perform retransmission of the feedback information even if the autonomous gap is released at a second point in time after the first point in time. Accordingly, it is possible to prevent unnecessary HARQ operations from being performed, and to prevent waste of radio resources.

The above-described embodiments of the present invention can be implemented by various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

In the case of hardware implementation, the method according to embodiments of the present invention may be implemented in one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs) , FPGAs (Field Programmable Gate Arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to embodiments of the present invention may be implemented in the form of a module, a procedure or a function for performing the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The foregoing description of the preferred embodiments of the present invention has been presented for those skilled in the art to make and use the invention. 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 or scope of the present invention as defined by the following claims It can be understood that Accordingly, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention.

In this specification, both the invention and the method invention are explained, and the description of both inventions can be supplemented as necessary.

100: terminal device
110: Transmission module
120: Processor
130: Receiving module

Claims (5)

A method of operating a Hybrid Automatic Repeat request (HARQ) of a terminal in a wireless communication system,
Receiving uplink resource allocation information from a base station;
Transmitting data based on the received uplink resource allocation information; And
Receiving feedback information on the data transmission from the base station,
And if the autonomous gap is set at a first time point at which the feedback information is received, the terminal does not receive the feedback information. The method according to claim 1,
And if the feedback information is not received by the set autonomous gap, performing a determination of an acknowledgment or a negative response to the feedback information. 3. The method of claim 2,
And if the feedback information is not received due to the set autonomous gap, the UE sets feedback information as an acknowledgment and does not retransmit the data. 3. The method of claim 2,
And does not perform retransmission of the feedback information even if the autonomous gap is released at the second time point after the first time point. A terminal apparatus for performing a Hybrid Automatic Repeat request (HARQ) operation in a wireless communication system,
A receiving module for receiving information from an external device;
A transmission module for transmitting information to an external device; And
A processor for controlling the receiving module and the transmitting module,
The processor comprising:
Receiving uplink resource allocation information from the base station using the reception module,
Transmitting data through the transmission module based on the received uplink resource allocation information,
Receiving feedback information on the data transmission from the base station using the receiving module,
And the terminal does not receive the feedback information when an autonomous gap is set at a first time point at which the feedback information is received.

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