WO2016010276A1 - Data retransmission processing method and apparatus therefor - Google Patents

Abstract

The present invention relates to a data retransmission processing method and an apparatus therefor and, more specifically, to a method and apparatus for a hybrid automatic repeat request (HARQ) operation of a terminal and a base station which perform communication using an unlicensed band cell. In particular, the present invention provides a method and apparatus for processing data retransmission by a terminal, the method comprising the steps of: performing downlink data reception or uplink data transmission in the unlicensed band cell; receiving downlink control information including scheduling information for HARQ retransmission when the downlink data reception or the uplink data transmission fails; and performing the HARQ retransmission for downlink data or uplink data in a licensed band cell, wherein the unlicensed cell is a cell using a frequency in an unlicensed band which one or more communication systems share.

Description

Data retransmission processing method and apparatus therefor

The present invention relates to a data retransmission processing method and apparatus thereof. More specifically, the present invention relates to a method and apparatus for operating a hybrid automatic repeat request (HARQ) of a terminal and a base station for performing communication using an unlicensed band cell.

As communication systems have evolved, consumers, such as businesses and individuals, have used a wide variety of wireless terminals. Mobile communication systems such as LTE (Long Term Evolution) and LTE-Advanced of the current 3GPP series are high-speed, high-capacity communication systems that can transmit and receive various data such as video and wireless data, out of voice-oriented services. The development of technology capable of transferring large amounts of data is required. Meanwhile, as a plurality of cell or small cell deployments are introduced, a technique for allowing carrier aggregation to be applied in various deployment scenarios has been discussed.

Meanwhile, the carrier merging technology is a technology for improving data transmission / reception rate by merging one or more component carriers to transmit and receive data, and thus, an available frequency is increased for the terminal, thereby processing a large amount of data at high speed.

However, there is a problem in that a frequency for a mobile communication network is limited and a limit exists in providing a high speed and large data transmission / reception rate to a large number of users in a situation where the number of mobile communication subscribers is increased.

In addition, each frequency band is used by different wireless communication systems according to the policy, there is a problem that the compatibility is poor.

The present invention for solving the above problems is to propose a method that can ensure the reliability of the data when different wireless communication systems transmit and receive data using the same frequency band.

In addition, the present invention intends to define a specific HARQ retransmission operation when the terminal and the base station communicate using a cell using an unlicensed band frequency.

According to the present invention for solving the above problems, a method for processing data retransmission by a terminal, the step of performing downlink data reception or uplink data transmission in an unlicensed band cell and downlink data reception or uplink data transmission fails Receiving downlink control information including scheduling information for hybrid automatic repeat request (HARQ) retransmission; And performing a HARQ retransmission operation on downlink data or uplink data in a licensed band cell, wherein the unlicensed band cell is a cell using a frequency of an unlicensed band shared by one or more communication systems.

In addition, the present invention provides a method for processing data retransmission by the base station, the step of performing downlink data transmission or uplink data reception in the unlicensed band cell, and when downlink data transmission or uplink data reception fails, HARQ ( Hybrid automatic repeat request) transmitting downlink control information including scheduling information for retransmission and performing a HARQ retransmission operation on downlink data or uplink data in a licensed band cell. It provides a method that is a cell using a frequency of an unlicensed band shared by one or more communication systems.

In addition, the present invention provides a terminal for processing data retransmission, a control unit performing downlink data reception or uplink data transmission in an unlicensed band cell, and when the downlink data reception or uplink data transmission fails, HARQ (Hybrid automatic) repeat request) including a receiving unit for receiving downlink control information including scheduling information for retransmission, wherein the control unit performs a HARQ retransmission operation for downlink data or uplink data in a licensed band cell, and the unlicensed band cell Provided is a terminal device which is a cell using a frequency of an unlicensed band shared by one or more communication systems.

In addition, the present invention provides a base station processing data retransmission, a control unit performing downlink data transmission or uplink data reception in an unlicensed band cell, and when the downlink data transmission or uplink data reception fails, HARQ (Hybrid automatic) repeat request) including a transmitter for transmitting downlink control information including scheduling information for retransmission, wherein the control unit performs a HARQ retransmission operation on downlink data or uplink data in a licensed band cell, and an unlicensed band cell Provided is a base station apparatus which is a cell using a frequency of an unlicensed band shared by one or more communication systems.

The present invention described above provides an effect of ensuring the reliability of data when different wireless communication systems transmit and receive data using the same frequency band.

In addition, the present invention provides an effect of preventing the ambiguity of the terminal operation by defining a specific HARQ retransmission operation in the communication between the terminal and the base station using a cell using an unlicensed band frequency.

1 exemplarily illustrates a layer 2 structure for downlink carrier aggregation.

FIG. 2 is a diagram illustrating a layer 2 structure for uplink carrier aggregation. FIG.

3 is a diagram illustrating an OFDM symbol for transmitting a control signal in one subframe by way of example.

FIG. 4 is a diagram for describing self-carrier scheduling and cross-carrier scheduling on a multiple carrier.

5 is a diagram for describing a downlink control information format.

FIG. 6 is a diagram for describing an operation of a terminal performing communication using a licensed band and an unlicensed band.

7 is an exemplary diagram for describing an available period in an unlicensed band cell.

8 is a view for explaining the operation of the terminal according to an embodiment of the present invention.

9 is a view for explaining the operation of the base station according to another embodiment of the present invention.

10 is a view showing the configuration of a user terminal according to another embodiment of the present invention.

11 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

The wireless communication system in the present invention is widely deployed to provide various communication services such as voice, packet data, and the like. The wireless communication system includes a user equipment (UE) and a base station (base station, BS, or eNB). In the present specification, a user terminal is a generic concept meaning a terminal in wireless communication. In addition, user equipment (UE) in WCDMA, LTE, and HSPA, as well as mobile station (MS) in GSM, user terminal (UT), and SS It should be interpreted as a concept that includes a subscriber station, a wireless device, and the like.

A base station or a cell generally refers to a station that communicates with a user terminal, and includes a Node-B, an evolved Node-B, an Sector, a Site, and a BTS. Other terms such as a base transceiver system, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and a small cell may be called.

In other words, in the present specification, a base station or a cell is a generic meaning indicating some areas or functions covered by a base station controller (BSC) in CDMA, a Node-B in WCDMA, an eNB or a sector (site) in LTE, and the like. It should be interpreted as, and it is meant to cover all the various coverage areas such as megacell, macrocell, microcell, picocell, femtocell and relay node, RRH, RU, small cell communication range.

Since the various cells listed above have a base station for controlling each cell, the base station may be interpreted in two senses. i) the device providing the megacell, the macrocell, the microcell, the picocell, the femtocell, the small cell in relation to the wireless area, or ii) the wireless area itself. In i) all devices which provide a given wireless area are controlled by the same entity or interact with each other to cooperatively configure the wireless area to direct the base station. The eNB, RRH, antenna, RU, LPN, point, transmit / receive point, transmit point, receive point, and the like, according to the configuration of the radio region, become an embodiment of the base station. In ii), the base station may indicate the radio area itself to receive or transmit a signal from a viewpoint of a user terminal or a neighboring base station.

Therefore, megacells, macrocells, microcells, picocells, femtocells, small cells, RRHs, antennas, RUs, low power nodes (LPNs), points, eNBs, transmit / receive points, transmit points, and receive points are collectively referred to as base stations. do.

In the present specification, the user terminal and the base station are two transmitting and receiving entities used to implement the technology or technical idea described in this specification in a comprehensive sense and are not limited by the terms or words specifically referred to. The user terminal and the base station are two types of uplink or downlink transmitting / receiving subjects used to implement the technology or the technical idea described in the present invention, and are used in a generic sense and are not limited by the terms or words specifically referred to. Here, the uplink (Uplink, UL, or uplink) refers to a method for transmitting and receiving data to the base station by the user terminal, the downlink (Downlink, DL, or downlink) means to transmit and receive data to the user terminal by the base station It means the way.

There is no limitation on the multiple access scheme applied to the wireless communication system. Various multiple access techniques such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), OFDM-FDMA, OFDM-TDMA, OFDM-CDMA Can be used. One embodiment of the present invention can be applied to resource allocation in the fields of asynchronous wireless communication evolving to LTE and LTE-Advanced through GSM, WCDMA, HSPA, and synchronous wireless communication evolving to CDMA, CDMA-2000 and UMB. The present invention should not be construed as being limited or limited to a specific wireless communication field, but should be construed as including all technical fields to which the spirit of the present invention can be applied.

The uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme that is transmitted using different times, or may use a frequency division duplex (FDD) scheme that is transmitted using different frequencies.

In addition, in systems such as LTE and LTE-Advanced, a standard is configured by configuring uplink and downlink based on one carrier or a pair of carriers. The uplink and the downlink include a Physical Downlink Control CHannel (PDCCH), a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid ARQ Indicator CHannel (PHICH), a Physical Uplink Control CHannel (PUCCH), an Enhanced Physical Downlink Control CHannel (EPDCCH), and the like. Control information is transmitted through the same control channel, and data is configured by a data channel such as a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH).

On the other hand, control information may also be transmitted using an enhanced PDCCH (EPDCCH or extended PDCCH).

In the present specification, a cell means a component carrier having a coverage of a signal transmitted from a transmission / reception point or a signal transmitted from a transmission point or a transmission / reception point, and the transmission / reception point itself. Can be.

A wireless communication system to which embodiments are applied may be a coordinated multi-point transmission / reception system (CoMP system) or a coordinated multi-antenna transmission scheme in which two or more transmission / reception points cooperate to transmit a signal. antenna transmission system), a cooperative multi-cell communication system. The CoMP system may include at least two multiple transmission / reception points and terminals.

The multiple transmit / receive point is at least one having a base station or a macro cell (hereinafter referred to as an eNB) and a high transmission power or a low transmission power in a macro cell region, which is wired controlled by an optical cable or an optical fiber to the eNB. May be RRH.

In the following, downlink refers to a communication or communication path from a multiple transmission / reception point to a terminal, and uplink refers to a communication or communication path from a terminal to multiple transmission / reception points. In downlink, a transmitter may be part of multiple transmission / reception points, 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 multiple transmission / reception points.

Hereinafter, a situation in which a signal is transmitted and received through a channel such as a PUCCH, a PUSCH, a PDCCH, an EPDCCH, and a PDSCH may be expressed in the form of 'sending and receiving a PUCCH, a PUSCH, a PDCCH, an EPDCCH, and a PDSCH.'

In addition, hereinafter, a description of transmitting or receiving a PDCCH or transmitting or receiving a signal through the PDCCH may be used as a meaning including transmitting or receiving an EPDCCH or transmitting or receiving a signal through the EPDCCH.

That is, the physical downlink control channel described below may mean PDCCH or EPDCCH, and may also be used to include both PDCCH and EPDCCH.

In addition, for convenience of description, the EPDCCH, which is an embodiment of the present invention, may be applied to the portion described as the PDCCH, and the EPDCCH may be applied to the portion described as the EPDCCH as an embodiment of the present invention.

Meanwhile, high layer signaling described below includes RRC signaling for transmitting RRC information including an RRC parameter.

The eNB performs downlink transmission to the terminals. The eNB includes downlink control information and an uplink data channel (eg, a physical downlink shared channel (PDSCH), which is a primary physical channel for unicast transmission, and scheduling required to receive the PDSCH. For example, a physical downlink control channel (PDCCH) for transmitting scheduling grant information for transmission on a physical uplink shared channel (PUSCH) may be transmitted. Hereinafter, the transmission and reception of signals through each channel will be described in the form of transmission and reception of the corresponding channel.

With the introduction of carrier aggregation (CA) technology, radio resources for uplink or downlink data transmission may be allocated to one UE through a plurality of carriers or serving cells. Therefore, it is possible to support an improved data transmission rate as compared with the existing communication method operating in a single carrier or serving cell.

As CA technology is supported, in case of a CA capable terminal belonging to the coverage of a base station supporting a CA, a primary cell connected through an initial RRC connection / configuration procedure with the base station In addition to SRC, a Scell (Secandary cell) addition / release process may be performed through an RRC connection reconfiguration process. In addition, the CA capable terminal may additionally combine up to five component carriers or serving cells through Scell activation / deactivation through MAC CE (Control Element) signaling.

1 exemplarily illustrates a layer 2 structure for downlink carrier aggregation. FIG. 2 is a diagram illustrating a layer 2 structure for uplink carrier aggregation. FIG.

In addition, in the case of a UE to which CA is applied, an independent HARQ entity is defined for each CC or serving cell when uplink or downlink data transmission is performed as shown in FIGS. 1 and 2, and is independent for each CC or serving cell. HARQ procedure may be operated.

As described above, HARQ entities are defined for each CC or serving cell, and as the HARQ procedure is independently performed for each CC or serving cell, a transport block (TB) in which initial transmission is performed through an arbitrary CC or serving cell is performed. Retransmission is performed through the same CC or serving cell.

3 is a diagram illustrating an OFDM symbol for transmitting a control signal in one subframe by way of example.

Referring to FIG. 3, the control region includes transmission of PHICH, PCFICH, and PDCCH. In this case, the PDCCH is spread evenly allocated to the number of OFDM symbols to which the PDCCH indicated by the PCFICH is transmitted, except for the resources in which the PHICH and the PCFICH are used.

FIG. 4 is a diagram for describing self-carrier scheduling and cross-carrier scheduling on a multiple carrier.

Referring to FIG. 4, when a PDSCH is transmitted on a multiple carrier, transmission of a PDSCH indicated by a control channel transmitted in every subframe can be confirmed. FIG. 4A is a diagram illustrating self-carrier scheduling on multiple carriers, and independently schedules a PDSCH on each carrier. For example, a PDCCH exists separately for each carrier, and the PDCCH of each carrier schedules the PDSCH of the corresponding carrier. That is, data is transmitted in each carrier by a control channel transmitted every subframe within a 1 ms subframe.

4B is a diagram illustrating a cross-carrier scheduling operation on multiple carriers, and relates to a case in which PDSCHs for multiple carriers are configured in one carrier. For example, a PDCCH existing in one carrier may schedule a PDSCH that can be transmitted on multiple carriers. Similarly to the case of (A) of FIG. 4B, data is transmitted in multiple carriers by a control channel transmitted every subframe within a 1 ms subframe.

5 is a diagram for describing a downlink control information format.

Referring to FIG. 5, a downlink control information (DCI) format indicating scheduling grant for uplink or downlink transmission may be identified. According to each uplink or downlink transmission method and usage, DCI formats are separately transmitted.

<Licensed Assisted Access using LTE in unlicensed spectrum>

Mobile telecommunications operators in each country used the government licensed spectrum (licensed spectrum) exclusively to configure the radio cell, based on this to provide a wireless communication service for the user terminal. Therefore, a radio access technology (RAT) for efficiently using a limited frequency band is intended to provide high spectral efficiency through technologies such as MIMO, ICIC, and CoMP. In addition, we conducted a study on carrier aggregation (CA) technology that can support a higher data rate by merging a plurality of carriers present in consecutive or discontinuous frequency bands.

However, as mobile devices with high processing power, including smart phones and tablets, have recently been introduced, user's mobile traffic is rapidly increasing. Thus, each wireless carrier needs a number of frequency resources to cover the improved mobile traffic. However, licensed band frequency resources are limited or limited depending on the policy situation of each country.

In this situation, there is an increasing need for providing LTE / LTE-Advanced services through unlicensed spectrum, which is used to provide short-range wireless communication services such as WiFi and Bluetooth.

However, in the case of an unlicensed band, unlike a licensed band, a plurality of users, including individuals, are freely available to provide wireless communication service within the regulation of each country, not a wireless channel exclusively used by any operator. .

Therefore, signal interference and coexistence with other communication systems may occur when providing an LTE / LTE-Advanced service through an unlicensed band. For example, if a user wants to provide a mobile communication service such as LTE using an unlicensed band, co-existence with various short range wireless communication protocols, such as WiFi, Bluetooth, and NFC, is already provided through the unlicensed band. Problems may arise. In addition, a co-existence problem may occur for each LTE operator. Therefore, there is a need for a method for solving this problem.

For example, when providing an LTE / LTE-Advanced service through an unlicensed band, sensing a power level of a radio channel or carrier to be used before transmitting a radio signal to avoid interference or collision between respective radio communication services. It may support a wireless channel access (LBT) -based wireless channel access (LBT) method for determining the availability of the corresponding radio channel or carrier. In this case, if a specific radio channel or carrier of the unlicensed band is in use by another wireless communication protocol or another operator, there is a possibility that it will be restricted from providing LTE / LTE-Advanced service through the corresponding band. Therefore, unlike LTE / LTE-Advanced service through a licensed band in providing an LTE / LTE-Advanced service through an unlicensed band, QoS desired by a user cannot be guaranteed.

FIG. 6 is a diagram for describing an operation of a terminal performing communication using a licensed band and an unlicensed band.

Referring to FIG. 6, in case of LTE / LTE-A service provision through an unlicensed band, a licensed-assisted access scheme LTE through carrier aggregation with a carrier or a cell configured through a licensed band Consider providing services. In this case, the primary carrier supports a frame structure in the form of FDD or TDD through the licensed band, and in the case of a secondary carrier configured through the unlicensed band in the form of downlink only. Can be configured. Alternatively, the secondary carrier configured through the unlicensed band may be in the form of supporting both uplink and downlink. In other words, when the UE performs communication by performing carrier aggregation, the primary carrier may process both uplink and downlink using a licensed band exclusively used by the corresponding mobile communication system. Meanwhile, the UE may process only downlink-only data using a frequency using an unlicensed band as a secondary carrier. Alternatively, the terminal may process both uplink and downlink data through the secondary carrier.

Hereinafter, for convenience of understanding, a cell configured through the unlicensed band of FIG. 6 will be referred to as an unlicensed band cell. However, this is for convenience of description and has no limitation on its name, and may be used to include all cells of a mobile communication system using an unlicensed band frequency. That is, an unlicensed band cell refers to a cell using an unlicensed band frequency shared by one or more communication systems.

The present invention provides a method for stably processing data retransmission that may occur in a time interval in which an unlicensed band frequency cannot be used when communication is performed in an unlicensed band cell using frequencies of an unlicensed band shared by multiple communication systems. And an apparatus.

7 is an exemplary diagram for describing an available period in an unlicensed band cell.

Referring to FIG. 7, in the case of an unlicensed band cell formed by an unlicensed band frequency by any one operator, an unlicensed band cell formed by another operator in a corresponding frequency band or another radio access technology such as WiFi or Bluetooth (Radio) Access frequency (RAT) systems share the frequency band exclusively. Accordingly, when the corresponding frequency band is available through LBT (Listen before talk), it is possible to support the terminal by configuring an unlicensed band cell through the frequency band of the corresponding unlicensed band for a specific time. However, even if the unlicensed band cell is configured through the corresponding unlicensed band frequency, after a certain time, the specific frequency band must be emptied for another operator or another communication system for a specific time.

In the present invention, for convenience of understanding, as shown in FIG. 7, a time period during which an arbitrary carrier configures an unlicensed band cell in an arbitrary frequency band and can support a terminal of the corresponding carrier is referred to as an unlicensed band cell available period. In addition, a time period in which an unlicensed band cell cannot be configured in a corresponding frequency band is referred to as an unlicensed band cell unavailable section. However, this is also for convenience of description and the name is not limited.

Meanwhile, a UE access method for an unlicensed band cell configured in an unlicensed spectrum may be configured as carrier aggregation or dual connectivity (DC) together with a normal LTE cell configured in a licensed spectrum. have. In this case, the general LTE cell may be configured as a primary cell.

Meanwhile, when an unlicensed band cell forms a CA or DC together with a general cell, according to the HARQ operation scheme for a secondary cell defined in an existing CA or DC, an independent HARQ process is based on the unlicensed band cell. Data transmission and reception should be made. That is, when a reception failure for data transmitted through an unlicensed band cell is retransmitted, the corresponding unlicensed band cell should be performed. In other words, when data is transmitted and received for any UE supporting an unlicensed band cell configured in an unlicensed band, any transport block constituting the corresponding data is a PDSCH or uplink subframe of a downlink subframe configured in an unlicensed band cell available period. In case of transmission through the PUSCH resource of the frame, when the reception of the corresponding PDSCH or PUSCH failed, retransmission for the corresponding transport block should also be performed through an uplink subframe or a downlink subframe of the same unlicensed band cell.

However, if the unlicensed band cell falls into an unlicensed band cell unavailable period for a predetermined time after initial transmission for the corresponding transport block, a downlink subframe or an uplink subframe of the unlicensed band cell for retransmission can be secured. Do not have A problem occurs.

Accordingly, a terminal and a base station performing communication using an unlicensed band cell have a problem in that communication data reliability due to data loss or data loss cannot be guaranteed when processing data according to a conventional data retransmission scheme.

Accordingly, the present invention has been proposed to propose a HARQ retransmission scheme that can ensure data reliability even when using an unlicensed band cell. Specifically, the present invention proposes a resource allocation method for PUSCH or PDSCH retransmission, which is an uplink or downlink data channel in an unlicensed band cell. In particular, we propose a PDSCH or PUSCH retransmission method in each case where cross carrier scheduling and self carrier scheduling are applied. For example, the cross-carrier scheduling case in which the scheduling control information for the PDSCH or the PUSCH of the corresponding unlicensed band cell is always transmitted through the PDCCH or EPDCCH of the licensed band and the scheduling control information for the unlicensed band cell are the PDCCH or EPDCCH of the unlicensed band cell. A method of retransmitting data in each case to which self-carrier scheduling is directly transmitted is applied.

Hereinafter, each embodiment of the present invention will be described in more detail with reference to the drawings.

8 is a view for explaining the operation of the terminal according to an embodiment of the present invention.

The present invention provides a method for a UE to process data retransmission, when performing downlink data reception or uplink data transmission in an unlicensed band cell, and when downlink data reception or uplink data transmission fails, HARQ (Hybrid automatic) repeat request) receiving downlink control information including scheduling information for retransmission and performing HARQ retransmission operation on downlink data or uplink data in a licensed band cell, wherein the unlicensed band cell includes one or more It provides a method that is a cell using the frequency of the unlicensed band shared by the communication system.

Referring to FIG. 8, the terminal of the present invention includes performing downlink data reception or uplink data transmission in an unlicensed band cell (S810). For example, the terminal may receive downlink data in an unlicensed band cell. Alternatively, the terminal may transmit uplink data in the unlicensed band cell. The terminal may receive only downlink data or only uplink data through the unlicensed band cell according to the configuration of the unlicensed band cell or the configuration of the base station. As another example, the terminal may receive and transmit downlink data and uplink data through the unlicensed band cell. In addition, as described above, the terminal may configure carrier aggregation using a licensed band cell and an unlicensed band cell. Alternatively, the terminal may configure dual connectivity using a licensed band cell and an unlicensed band cell. Carrier aggregation is a method of communicating with the terminal by configuring a licensed band cell and an unlicensed band cell in the same base station, dual connectivity is a base station constituting the licensed band cell and the base station constituting the unlicensed band cell is connected to the non-ideal backhaul It means the case. That is, the present invention can be applied to the case where the UE configures carrier aggregation using the unlicensed band cell and the licensed band cell and when the dual connectivity is configured.

Meanwhile, when the downlink data reception or the uplink data transmission fails, the terminal may include receiving downlink control information including scheduling information for HARQ retransmission (S820). For example, the terminal may not receive downlink data transmitted by the base station. Or, the terminal may not normally decode downlink data transmitted by the base station. In this case, the terminal should receive again from the base station through the HARQ process for the data that has not been received. In order to receive the missing data again, the terminal must receive scheduling information related to radio resources through which the missing data is transmitted.

Similarly, even when the terminal transmits uplink data, the UE performs an operation according to the HARQ process to receive data without missing the base station. That is, when the base station does not normally receive the uplink data transmitted by the terminal, the terminal should receive downlink control information including scheduling information for retransmission from the base station for retransmission of the missing uplink data. The terminal checks the UL grant of the received downlink control information and retransmits the missing uplink data through the corresponding radio resource.

If necessary, the downlink control information may include downlink assignment information or uplink grant information. In addition, according to each embodiment to be described in detail below, the downlink control information includes information indicating a cell for retransmission of missing data or information indicating whether to change the cell for retransmission or downlink allocation information It may also include information indicating whether or not for retransmission.

Meanwhile, the terminal may include performing a HARQ retransmission operation on downlink data or uplink data in the licensed band cell (S830). For example, when some data of the downlink data received through the unlicensed band cell is missing, the terminal may receive the missing downlink data through the licensed band cell. Alternatively, when retransmission of uplink data transmitted through the unlicensed band cell is required, the terminal may retransmit the corresponding uplink data through the licensed band cell. To this end, the terminal may perform an HARQ operation in the licensed band cell based on the downlink control information received in step S820.

As described above, when the UE transmits and receives data through the unlicensed band cell, the terminal may perform stable data transmission and reception even if the characteristics of the unlicensed band cell exist.

In the following, each embodiment of the present invention described above is divided and described in more detail.

First embodiment: HARQ retransmission is performed through a primary cell of a licensed band.

When the HARQ operation for data transmission and reception in the unlicensed band cell is required, the terminal of the present invention may perform the HARQ operation through the primary cell of the licensed band constituting carrier aggregation or dual connectivity. In this case, the user equipment determines whether a downlink assignment or an uplink grant is information for initial transmission of downlink data or uplink data or information for HARQ retransmission operation from the base station. Downlink control information including a may be received.

For example, when the reception failure of the initial transmission of the PUSCH occurs in the PDSCH or the uplink subframe through the downlink subframe of the unlicensed band cell, HARQ retransmission for each of the licensed band to the primary cell Can be defined to be through. In this case, when the UE is applied with dual connectivity in the licensed band, the primary cell in which HARQ retransmission for PDSCH / PUSCH initial transmission of the unlicensed band cell is performed is a primary cell of a MCG (Master Cell Group) or a SCG (Secondary). Cell may be defined as a special cell. Here, MCG means a cell group associated with the master base station, SCG means a cell group associated with the secondary base station. In addition, the primary cell may mean a cell having a PUSCH transmission function, establishing an RRC connection with the terminal, and serving as a reference for handover. The special cell refers to a cell having a PUSCH function in the secondary cell group, and may also be referred to as a PSCell.

For example, according to the setting of a new data indicator bit included in a DL assignment DCI for an unlicensed band cell, whether the corresponding downlink allocation is scheduling information for initial transmission of downlink data. It may be distinguished whether scheduling information for retransmission according to the HARQ operation. That is, when the downlink allocation DCI is the initial transmission downlink allocation DCI for any HARQ process number according to whether it is PDSCH resource allocation control information for initial transmission or PDSCH resource allocation control information for HARQ retransmission, It may be defined to mean PDSCH transmission resource allocation in the corresponding unlicensed band cell. In addition, in the case of downlink allocation DCI for HARQ retransmission for a certain HARQ process number, it may be defined to mean PDSCH transmission resource allocation in a primary cell of a licensed band.

HARQ operation on the uplink data may also be performed similarly as described above.

For example, even in the case of uplink grant DCI (UL grant DCI) for the unlicensed band cell, whether the uplink grant information is for PUSCH initial transmission according to whether a new data indicator bit is set. Whether it is for retransmission can be distinguished. That is, when a new data indication bit is an UL grant for a corresponding initial transmission, it may be defined to mean PUSCH resource allocation in an uplink subframe of an unlicensed band cell. In addition, when the new data indication bit is an uplink grant for HARQ retransmission, it may be defined to mean PUSCH resource allocation in a primary cell of a licensed band.

As another example, in case of retransmission through PHICH NACK without separately transmitting and receiving an uplink grant for retransmission, corresponding PUSCH retransmission is performed in a primary cell of a licensed band according to UL grant DCI in which initial transmission for a corresponding HARQ process is performed. It can also be defined to

Meanwhile, the present embodiment may be equally applied regardless of whether self-carrier scheduling or cross-carrier scheduling is applied as a scheduling method for an unlicensed band cell. However, in case of self-carrier scheduling, when an unlicensed band cell enters an unavailable period at the time of HARQ retransmission, a downlink allocation DCI for the PDSCH retransmission or an uplink grant DCI for PUSCH retransmission may be received. Unexpected problems may arise. Therefore, in this case, it may be defined that a downlink allocation DCI for the corresponding PDSCH retransmission or an uplink grant DCI for the PUSCH retransmission is received through the PDCCH or the EPDCCH of the primary cell. In this case, a method for distinguishing whether the corresponding DCI is for a primary cell having the same HARQ process number or for retransmission of a PDSCH or a PUSCH of an unlicensed band cell that has entered an unusable interval, is transmitted through the primary cell. The DCI format may be defined to include a Carrier Indicator Field (CIF) for a predetermined time, and may be distinguished through this. As another example, a new information area for distinguishing this may be defined and included in a corresponding DCI format for a predetermined time.

Second Embodiment: Performing HARQ Retransmission Operation Through Scheduling Cell of Licensed Band

This embodiment is a method applicable when cross-carrier scheduling for an unlicensed band cell is configured. The HARQ retransmission is performed through a scheduling cell of a licensed band in which scheduling control information for PDSCH or PUSCH of the unlicensed band cell is transmitted. This can be done. That is, based on the CIF (Carrier Indicator Field) information included in the downlink allocation DCI transmitted through the corresponding license band and the new data indication bit, whether the corresponding DCI is resource allocation for initial data transmission in the unlicensed band cell or HARQ retransmission. Can be set to distinguish whether or not resource allocation for operation.

For example, if a specific DCI is scheduling information for an unlicensed band cell according to CIF information, and a new data indication bit indicates initial transmission resource allocation information for any HARQ process number, the corresponding PDSCH is corresponding downlink allocation DCI. It may be defined to be transmitted through an unlicensed band cell according to the resource allocation information of. As another example, when a specific DCI is scheduling information for an unlicensed band cell according to CIF information and a new data indication bit indicates transmission resource allocation for HARQ retransmission, the corresponding PDSCH is corresponding license band according to resource allocation information of the corresponding DCI. It may be defined to be transmitted through the scheduling cell of.

Similarly, in the case of uplink data, an operation is performed by distinguishing whether the corresponding DCI is for initial transmission or HARQ retransmission based on the CIF information included in the uplink grant DCI transmitted through the license band and the new data indication bit. can do. For example, if DCI is scheduling information for an unlicensed band cell according to CIF, and a new data indication bit indicates initial transmission resource allocation information for HARQ process number, the corresponding PUSCH is included in the resource allocation information of the corresponding UL grant DCI. Accordingly, it may be defined to be transmitted through an unlicensed band cell. As another example, when the DCI is scheduling information for an unlicensed band cell according to CIF, and a new data indication bit indicates transmission resource allocation for HARQ retransmission, the corresponding PUSCH is corresponding license band according to resource allocation information of the corresponding UL grant DCI. It may be defined to be transmitted through the scheduling cell of. However, in case of retransmission through PHICH NACK without transmitting / receiving UL grant for retransmission separately, the PUSCH retransmission may be defined in the scheduling cell of the licensed band according to initial transmission resource allocation information for the PUSCH of the corresponding HARQ process number. have.

Third Embodiment: Selecting HARQ Retransmission Cell Based on State of Unlicensed Band Cell

In this embodiment, the cell on which the HARQ retransmission operation is performed may be determined according to whether an unlicensed band cell is available. That is, in an unlicensed band cell, retransmission is performed for a PDSCH or a PUSCH through the unlicensed band cell, and in an unusable interval, a PDSCH or PUSCH is used for a cell in a licensed band cell. Can be defined to be retransmission. When retransmission is performed for the PDSCH or the PUSCH using the licensed band cell, the cell of the licensed band where the HARQ retransmission operation is performed may be a primary cell of the first embodiment or a scheduling cell of the second embodiment.

Specifically, for example, if the unlicensed band cell is available period when HARQ retransmission is performed for PDSCH or PUSCH for initial transmission through unlicensed band cell, downlink allocation DCI for the corresponding HARQ retransmission A retransmission operation may be performed through a downlink subframe or an uplink subframe of an unlicensed band cell according to resource allocation information of a DL assignment DCI or UL grant DCI. If HARQ retransmission is performed for PDSCH or PUSCH for initial transmission through an unlicensed band cell, if the corresponding unlicensed band cell is in an unavailable period, the HARQ retransmission operation may be performed in the licensed band cell. . That is, the retransmission may be performed through the primary cell of the licensed band by applying the above-described first embodiment, or the retransmission may be performed by the scheduling cell of the licensed band by applying the second embodiment.

However, in the present embodiment, the state of the unlicensed band cell may be signaled to the corresponding terminal explicitly or implicitly. There is no restriction on the signaling method.

Fourth Embodiment: Method of Including Cell Change Indication Information in Downlink Control Information (DCI)

The terminal of the present invention may receive cell change indication information included in the downlink control information. For example, in the present embodiment, when a downlink allocation DCI or an uplink grant DCI for HARQ retransmission for PDSCH or PUSCH for which initial transmission is performed through an unlicensed band cell, a retransmission cell change indication region is defined in the corresponding DCI. Can be. The terminal may check whether the cell in which the retransmission is performed is changed through the information in the cell change indication information region.

In other words, when a transmission / reception failure for a PDSCH having any HARQ process number for which initial transmission is performed to an unlicensed band cell occurs, a cell change indication is provided to a downlink allocation DCI including PDSCH resource allocation information for HARQ retransmission of the corresponding downlink data. An information area may be defined and configured to signal to the UE whether to change a cell in which a corresponding PDSCH retransmission is performed. For example, if the cell change indication region is set to "0", the PDSCH retransmission is performed through the unlicensed band cell, and if the cell change indication region is set to "1", the license band cell The PDSCH retransmission may be configured through the MS. The cell on which PDSCH retransmission is performed may be a primary cell as in the first embodiment or may be a scheduling cell as in the second embodiment. However, the value of the cell change indication information area as exemplified above may be set to various values only as an example for convenience of understanding.

As described in the third embodiment, when the unlicensed band cell is not available at the time when the retransmission is performed, the retransmission may be performed through the licensed band cell regardless of the value of the cell change indication information region.

Meanwhile, in the case of retransmission for the PUSCH, the same method as in the case of the PDSCH described above may be applied.

Embodiment 5: The Unlicensed Band Cell Is Not Set to Support HARQ Operation

In the case of an unlicensed band cell, it may be defined that HARQ operation is not performed. That is, HARQ ACK / NACK feedback for PDSCH or PUSCH transmission through all unlicensed band cells is not performed, and retransmission for transmission / reception failure may be defined to be performed according to ARQ retransmission of a higher layer.

Alternatively, in the case of the available period according to the state of the unlicensed band cell, HARQ retransmission may be performed through the corresponding unlicensed band cell. Alternatively, if the state of the unlicensed band cell is an available interval, HARQ retransmission operation is performed in the licensed band cell as described in the first to fourth embodiments, and only for the unlicensed band cell when the corresponding unlicensed band cell is not available. All HARQ processes can be stopped. In this case, retransmission for the PDSCH or the PUSCH of the HARQ process that has not received the HARQ ACK may be defined to be performed at the ARQ stage. However, data that does not receive HARQ ACK during the HARQ process of an unlicensed band cell interrupted to minimize the corresponding ARQ retransmission delay is regarded as a transmission / reception failure in the ARQ stage and a status report from the terminal through the license band. You can define that retransmission happens without receiving).

As described above in detail by dividing each embodiment, the present invention relates to an HARQ procedure of an unlicensed band cell and a method for retransmitting HARQ, which may be performed in the form of one or a combination of the aforementioned various embodiments. In addition, the names described above are to aid the understanding of the present invention, and the rights of the present invention are not limited by the names.

The present invention described above can be equally applied to a base station. That is, when the base station transmits the downlink data and receives the uplink data, the above descriptions based on the terminal may be applied correspondingly or may be applied in the same manner. In the following, the present invention is briefly described again from the viewpoint of a base station.

9 is a view for explaining the operation of the base station according to another embodiment of the present invention.

The base station according to another embodiment of the present invention performs downlink data transmission or uplink data reception in an unlicensed band cell, and when the downlink data transmission or uplink data reception fails, HARQ (Hybrid automatic repeat request) retransmission The method may include transmitting downlink control information including scheduling information for performing a HARQ retransmission operation on downlink data or uplink data in a licensed band cell. Here, the unlicensed band cell may mean a cell using a frequency of the unlicensed band shared by one or more communication systems.

Referring to FIG. 9, the base station of the present invention includes performing downlink data transmission or uplink data reception in an unlicensed band cell (S910). For example, the base station may transmit downlink data to the terminal and may receive uplink data from the terminal. The base station may transmit and receive downlink data and uplink data using the aforementioned unlicensed band cell. In addition, the base station may set or configure carrier aggregation or dual connectivity in the terminal.

When the downlink data transmission or the uplink data reception fails, the base station may include transmitting downlink control information including scheduling information for HARQ retransmission (S920). For example, when downlink data transmission or uplink data reception fails, downlink control information (DCI) including scheduling information for data retransmission operation is transmitted. The downlink control information may be transmitted through an unlicensed band cell or a licensed band cell. That is, when the terminal configures carrier aggregation and cross carrier scheduling is set, downlink control information may be transmitted through a scheduling cell (licensed band cell).

The downlink control information may include different information according to each of the first to fifth embodiments described above. For example, the downlink control information may include information for identifying whether downlink allocation or uplink grant included in DCI is for initial data transmission or retransmission. As another example, the downlink control information may include cell change indication information indicating whether to change the cell on which the HARQ operation is to be performed. In addition, it may include a variety of information required to perform each embodiment of the present invention described above.

The base station may include performing a HARQ retransmission operation on downlink data or uplink data in the licensed band cell (S930). The base station may perform a HARQ operation on the licensed band cell for data transmitted and received in the unlicensed band cell. Specifically, the base station may perform HARQ retransmission operation in the primary cell or the scheduling cell of the licensed band. Alternatively, if the unlicensed band cell is not available and the retransmission operation is performed in the corresponding interval, the base station may perform the HARQ retransmission operation in the licensed band cell. Performing HARQ retransmission operation means allocating PDSCH or PUSCH resources for data retransmission in the corresponding licensed band cell.

In addition, the base station can perform all the operations of the present invention described with reference to the first to fifth embodiments.

As described above, the present invention provides an effect of ensuring the reliability of data when different wireless communication systems transmit and receive data using the same frequency band. In addition, the present invention provides an effect of preventing the ambiguity of the terminal operation by defining a specific HARQ retransmission operation in the communication between the terminal and the base station using a cell using an unlicensed band frequency.

A configuration of a terminal and a base station capable of carrying out the above-described present invention will be described with reference to the drawings.

10 is a view showing the configuration of a user terminal according to another embodiment of the present invention.

Referring to FIG. 10, the terminal 1000 of the present invention provides a control unit 1010 that performs downlink data reception or uplink data transmission in an unlicensed band cell, and when downlink data reception or uplink data transmission fails, HARQ. (Hybrid automatic repeat request) including a receiving unit 1030 for receiving downlink control information including scheduling information for retransmission, the control unit 1010 is a HARQ retransmission operation for downlink data or uplink data in a licensed band cell Do this. Here, the unlicensed band cell refers to a cell using a frequency of the unlicensed band shared by one or more communication systems.

The receiver 1030 receives downlink data, a signal, and a message from a base station through a corresponding channel.

Meanwhile, the receiver 1030 may receive downlink control information including information necessary to perform a HARQ retransmission operation according to each embodiment described above. For example, the downlink control information may be used to distinguish whether downlink assignment or uplink grant is information for initial transmission of downlink data or uplink data or information for HARQ retransmission operation. May contain information. As another example, the downlink control information may include cell change indication information indicating whether to change the cell on which the HARQ retransmission operation is performed.

The controller 1010 configures carrier aggregation or dual connectivity. In addition, in performing HARQ retransmission, the controller 1010 may perform the unlicensed band cell in an unlicensed band cell, and may perform the licensed band cell in an unlicensed band cell. Alternatively, the controller 1010 may determine a cell performing the HARQ retransmission operation based on the downlink control information, and perform the HARQ retransmission operation in the determined licensed band cell. For example, the licensed band cell may be a primary cell or a special cell and may be a scheduling cell.

In addition, the controller 1010 is a HARQ in the unlicensed band cell formed through the cell (or carrier) and CA (Carrier Aggregation) or DC (Dual Connectivity) in the licensed spectrum (licensed spectrum) necessary to carry out the present invention described above. Control the overall operation of the terminal needed to define the retransmission operation.

The transmitter 1130 transmits uplink control information, data, and a message to a base station through a corresponding channel.

11 is a diagram illustrating a configuration of a base station according to another embodiment of the present invention.

Referring to FIG. 11, the base station 1100 according to another embodiment of the present invention includes a control unit 1110 for performing downlink data transmission or uplink data reception in an unlicensed band cell and downlink data transmission or uplink data reception. If this fails, the transmitter 1120 for transmitting downlink control information including scheduling information for HARQ (Hybrid automatic repeat request) retransmission, the control unit 1110 is a downlink data or uplink in the licensed band cell HARQ retransmission operation may be performed on data. Here, the unlicensed band cell refers to a cell using a frequency of the unlicensed band shared by one or more communication systems.

The transmitter 1120 and the receiver 1130 are used to transmit and receive signals, messages, and data necessary for carrying out the above-described present invention.

The transmitter 1120 may transmit downlink control information necessary for performing the HARQ retransmission operation to the terminal. For example, the downlink control information may be used to distinguish whether downlink assignment or uplink grant is information for initial transmission of downlink data or uplink data or information for HARQ retransmission operation. May contain information. As another example, the downlink control information may include cell change indication information indicating whether to change the cell on which the HARQ retransmission operation is performed.

The controller 1110 sets carrier merge or dual connectivity of the terminal. In addition, in performing an HARQ retransmission operation, the controller 1110 may control the unlicensed band cell to be performed in the unlicensed band cell and the unlicensed band cell to be performed in the licensed band cell. Alternatively, the controller 1110 may determine a cell for performing the HARQ retransmission operation and control the performance of the HARQ retransmission operation in the determined licensed band cell. For example, the licensed band cell may be a primary cell or a special cell and may be a scheduling cell.

In addition, the controller 1110 is a HARQ in an unlicensed band cell formed through a cell (or carrier) and CA (Carrier Aggregation) or DC (Dual Connectivity) in a licensed spectrum required for carrying out the aforementioned invention It controls the overall base station's behavior necessary to define the retransmission behavior.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is related to the patent application No. 10-2014-0091305 filed in Korea on July 18, 2014 and the patent application No. 10-2015-0065260 filed in Korea on May 11, 2015. Priority is claimed under section (a) (35 USC § 119 (a)), all of which is incorporated herein by reference. In addition, if this patent application claims priority for the same reason for countries other than the United States, all its contents are incorporated into this patent application by reference.

Claims (20)

In the method for the terminal to process data retransmission, Performing downlink data reception or uplink data transmission in an unlicensed band cell; Receiving downlink control information including scheduling information for a hybrid automatic repeat request (HARQ) retransmission when the downlink data reception or the uplink data transmission fails; And Performing the HARQ retransmission operation on the downlink data or the uplink data in a licensed band cell, The unlicensed band cell is a cell using a frequency of an unlicensed band shared by one or more communication systems. The method of claim 1, The downlink control information, Downlink assignment or uplink grant includes information for distinguishing whether the downlink data or the uplink data is information for initial transmission or information for the HARQ retransmission operation. How to. The method of claim 1, The licensed band cell, If cross carrier scheduling is configured in the terminal, the method characterized in that the scheduling cell. The method of claim 1, The licensed band cell, If the carrier merge or dual connectivity is configured in the terminal, characterized in that the primary cell. The method of claim 1, The HARQ retransmission operation, The unlicensed band cell is performed in the unlicensed band cell in an available period, and the unlicensed band cell is performed in the licensed band cell in an interval where the unlicensed band cell is unavailable. The method of claim 1, The downlink control information, And cell change indication information indicating whether to change a cell on which the HARQ retransmission operation is performed. A method for a base station to process data retransmission, Performing downlink data transmission or uplink data reception in an unlicensed band cell; Transmitting downlink control information including scheduling information for hybrid automatic repeat request (HARQ) retransmission when the downlink data transmission or the uplink data reception fails; And Performing the HARQ retransmission operation on the downlink data or the uplink data in a licensed band cell, The unlicensed band cell is a cell using a frequency of an unlicensed band shared by one or more communication systems. The method of claim 7, wherein The downlink control information, Downlink assignment or uplink grant includes information for distinguishing whether the downlink data or the uplink data is information for initial transmission or information for the HARQ retransmission operation. How to. The method of claim 7, wherein The licensed band cell, If cross-carrier scheduling is configured for the terminal, the method characterized in that the scheduling cell. The method of claim 7, wherein The licensed band cell, If carrier aggregation or dual connectivity is configured in the terminal, characterized in that the primary cell. The method of claim 7, wherein The HARQ retransmission operation, The unlicensed band cell is performed in the unlicensed band cell in an available period, and the unlicensed band cell is performed in the licensed band cell in an unavailable period. The method of claim 7, wherein The downlink control information, And cell change indication information indicating whether to change a cell on which the HARQ retransmission operation is performed. In the terminal processing data retransmission, A control unit for performing downlink data reception or uplink data transmission in an unlicensed band cell; And If the downlink data reception or uplink data transmission fails, including a receiving unit for receiving downlink control information including scheduling information for the hybrid automatic repeat request (HARQ) retransmission, The controller performs the HARQ retransmission operation on the downlink data or uplink data in a licensed band cell, The unlicensed band cell is a cell using a frequency of an unlicensed band shared by one or more communication systems. The method of claim 13, The downlink control information, Downlink assignment or uplink grant includes information for distinguishing whether the downlink data or the uplink data is information for initial transmission or information for the HARQ retransmission operation. Terminal. The method of claim 13, The licensed band cell, And cross-carrier scheduling in the terminal, wherein the terminal is a scheduling cell. The method of claim 13, The licensed band cell, If the carrier merge or dual connectivity is configured in the terminal, the terminal characterized in that the primary cell. The method of claim 13, The HARQ retransmission operation, The terminal is performed in the unlicensed band cell when the unlicensed band cell is available, and is performed in the licensed band cell when the unlicensed band cell is unavailable. The method of claim 13, The downlink control information, And cell change indication information indicating whether to change a cell in which the HARQ retransmission operation is performed. A base station for processing data retransmission, A control unit for performing downlink data transmission or uplink data reception in an unlicensed band cell; And If the downlink data transmission or uplink data reception fails, including a transmitter for transmitting downlink control information including scheduling information for retransmission of a hybrid automatic repeat request (HARQ), The controller performs the HARQ retransmission operation on the downlink data or uplink data in a licensed band cell, And the unlicensed band cell is a cell using a frequency of an unlicensed band shared by one or more communication systems. The method of claim 19, The downlink control information, Downlink assignment or uplink grant includes information for distinguishing whether the downlink data or the uplink data is information for initial transmission or information for the HARQ retransmission operation. Base station.

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