Abstract:
A communication technique of fusing a 5th-generation (5G) communication for supporting higher data transmission rate beyond a 4th-generation (4G) system with an Internet of things (IoT) technology and a system thereof are provided. The present disclosure may be used for an intelligent service (for example, a smart home, a smart building, a smart city, a smart car or a connected car, health care, digital education, retail business, security and safety related service, or the like) based on the 5G communication technology and the IoT related technology. A communication method of a base station includes generating resource assignment information of an uplink burst including at least two consecutive uplink subframes of an unlicensed band; transmitting the resource assignment information to a terminal; and receiving uplink data from the terminal during the at least two consecutive uplink subframes.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application claims the benefit under 35 U.S.C. §119(e) of a U.S. Provisional application filed on May 12, 2016 in the U.S. Patent and Trademark Office and assigned Ser. No. 62/335,326, the entire disclosure of which is hereby incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure relates to a method and apparatus for assigning an uplink resource for an unlicensed band in a system sharing resources for device to device communications. 
       BACKGROUND 
       [0003]    To meet a demand for radio data traffic that is on an increasing trend since commercialization of a 4th-generation (4G) communication system, efforts to develop an improved 5th-generation (5G) communication system or a pre-5G communication system have been conducted. For this reason, the 5G communication system or the pre-5G communication system is called a beyond 4G network communication system or a post long term evolution (LTE) system. 
         [0004]    To achieve a high data transmission rate, the 5G communication system is considered to be implemented in a super high frequency (mmWave) band (e.g., like 60 GHz band). To relieve a path loss of a radio wave and increase a transfer distance of a radio wave in the mmWave band, in the 5G communication system, technologies such as beamforming, massive multi-input multi-output (massive MIMO), full dimensional MIMO (FD-MIMO), an array antenna, analog beamforming, and a large scale antenna have been discussed. 
         [0005]    Further, to improve a network of the system, in the 5G communication system, technologies such as an evolved small cell, an advanced small cell, a cloud radio access network (cloud RAN), an ultra-dense network, device to device communication (D2D), wireless backhaul, a moving network, cooperative communication, coordinated multi-points (CoMP), and interference cancellation have been developed. 
         [0006]    In addition, in the 5G system, hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM) modulation (FQAM) and sliding window superposition coding (SWSC) that are an advanced coding modulation (ACM) scheme and a filter bank multi carrier (FBMC), a non-orthogonal multiple access (NOMA), and a sparse code multiple access (SCMA) that are an advanced access technology, and so on have been developed. 
         [0007]    Meanwhile, the Internet is evolved to an Internet of things (IoT) network that transmits and receives information between distributed components such as things and processes the information, in a human-centered connection network on which human generates and consumes information. The Internet of everything (IoE) technology in which the big data processing technology, etc., by connection with a cloud server, etc., is combined with the IoT technology has also emerged. To implement the IoT, technology elements, such as a sensing technology, wired and wireless communication and network infrastructure, a service interface technology, and a security technology, have been required. Recently, technologies such as a sensor network, machine to machine (M2M), and machine type communication (MTC) for connecting between things have been studied. In the IoT environment, an intelligent Internet technology service that creates a new value in human life by collecting and analyzing data generated in the connected things may be provided. The IoT may be applied to fields, such as a smart home, a smart building, a smart city, a smart car or a connected car, a smart grid, health care, smart appliances, and an advanced healthcare service, by fusing and combining the existing information technology with various industries. 
         [0008]    Therefore, various tries to apply the 5G communication system to the IoT network have been conducted. For example, the 5G communication technologies such as the sensor network, the M2M, the MTC have been implemented by schemes such as the beamforming, the MIMO, the array antenna, or the like. The application of the cloud RAN as the big data processing technology described above may also be considered as an example of the fusing of the 5G technology with the IoT technology. 
         [0009]    The 5G system has considered a support for various services compared to the existing 4G system. For example, the most representative services are an enhanced mobile broadband (eMBB) communication service, an ultra-reliable and low latency communication (URLLC) service, a massive machine type communication (mMTC) service, an evolved multimedia broadcast/multicast service (eMBMS), etc. Further, a system providing the URLLC service may be referred to as an URLLC system, a system providing the eMBB service may be referred to as an eMBB system, and a system providing the mMTC service may be referred to as an mMTC system, and the like. In addition, the terms “service and system” may be interchangeably used with each other. 
         [0010]    The above information is presented as background information only to assist with understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure. 
       SUMMARY 
       [0011]    Aspects of the present disclosure are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present disclosure is to provide a method and an apparatus for transmitting and receiving a signal in a communication system. 
         [0012]    Another aspect of the present disclosure is to provide a method and an apparatus for controlling physical channel parameters of a communication link in a system sharing communication resources. 
         [0013]    Another aspect of the present disclosure is to provide a method and an apparatus for assigning a resource for a cellular network sharing resources in an unlicensed band. 
         [0014]    Another aspect of the present disclosure is to provide a method and an apparatus for assigning a resource for relieving a problem of a delay increase and a signaling load increase due to a listen before talk (LBT) failure in an unlicensed band. 
         [0015]    Another aspect of the present disclosure is to provide a method and an apparatus for minimizing a loss and more effectively using a frequency band for cellular communications in a shared band. 
         [0016]    In accordance with an aspect of the present disclosure, a communication method of a base station is provided. The communication method includes generating resource assignment information of an uplink burst including at least two consecutive uplink subframes transmittable and receivable through an unlicensed band, transmitting the resource assignment information to a terminal, and receiving an uplink data from the terminal during the at least two consecutive uplink subframes. 
         [0017]    The resource assignment information may include the information of the at least two uplink burst. 
         [0018]    The resource assignment information may include information of the number of uplink bursts and the number of uplink subframes included in each uplink burst. 
         [0019]    The resource assignment information may include information of a set of the uplink bursts in which the at least two uplink bursts are consecutive. 
         [0020]    In accordance with an aspect of the present disclosure, a communication method of a terminal is provided. The communication method includes receiving resource assignment information including information indicating at least two consecutive uplink subframes transmittable and receivable through an unlicensed band from a base station, determining whether at least one of the at least two consecutive uplink subframes is occupied, and transmitting an uplink data to the base station during the at least one uplink subframe if it is determined that the at least one uplink subframe is occupied. 
         [0021]    In accordance with an aspect of the present disclosure, a base station is provided. The base station includes a transceiver configured to transmit and receive a signal, and at least one processor configured to generate resource assignment information including information of an uplink burst including at least two consecutive uplink subframes transmittable and receivable through an unlicensed band, transmit the resource assignment information to a terminal, and receive an uplink data from the terminal during the at least two consecutive uplink subframes. 
         [0022]    In accordance with an aspect of the present disclosure, a terminal is provided. The terminal includes a transceiver configured to transmit and receive a signal, and at least one processor configured to receive from a base station the resource assignment information including information indicating at least two consecutive uplink subframes transmittable and receivable through an unlicensed band, check whether at least one of the at least two consecutive uplink subframes is occupied, and transmit an uplink data to the base station during the at least one uplink subframe if it is determined that the at least one uplink subframe is occupied. 
         [0023]    According to an embodiment of the present disclosure, it is possible to provide the method and apparatus for controlling physical channel parameters of a communication link in a system sharing communication resources. 
         [0024]    Also, according to an embodiment of the present disclosure, it is possible to provide the method and apparatus for assigning a resource for a cellular network sharing resources in an unlicensed band. 
         [0025]    Further, according to one embodiment of the present disclosure, it is possible to provide the method and apparatus for assigning a resource for relieving a problem of a delay increase and a signaling load increase due to a LBT failure in an unlicensed band. 
         [0026]    In addition, according to an embodiment of the present disclosure, it is possible to provide the method and apparatus for minimizing a loss and more effectively using a frequency band for cellular communications in a shared band. 
         [0027]    Objects aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the present disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    The above and other aspects, features, and advantages of certain embodiments of the present disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
           [0029]      FIG. 1  is a diagram illustrating an example of a communication procedure through an unlicensed band in the case of frame based equipment (FBE) according to an embodiment of the present disclosure; 
           [0030]      FIG. 2  is a diagram illustrating an example of a communication procedure through an unlicensed band in the case of load based equipment (LBE) according to an embodiment of the present disclosure; 
           [0031]      FIG. 3  is a diagram illustrating a procedure for determining transmission capacity of a transmitting/receiving link in a wireless communication system according to an embodiment of the present disclosure; 
           [0032]      FIG. 4  is a diagram illustrating an example of a downlink scheduling procedure according to an embodiment of the present disclosure. 
           [0033]      FIG. 5  is a diagram illustrating an example of an uplink scheduling procedure according to an embodiment of the present disclosure; 
           [0034]      FIG. 6  is a diagram illustrating an example of semi-persistent scheduling (SPS) assignment according to an embodiment of the present disclosure; 
           [0035]      FIG. 7  is a diagram illustrating an example of an SPS assignment in an unlicensed band according to an embodiment of the present disclosure; 
           [0036]      FIG. 8  is a diagram illustrating an example of an SPS assignment according to an embodiment of the present disclosure; 
           [0037]      FIG. 9  is a diagram illustrating an example of SPS assignment according to an embodiment of the present disclosure; 
           [0038]      FIGS. 10, 11, 12, 13, 14, and 15  are diagrams illustrating examples of SPS consecutive subframe assignment method according to various embodiments of the present disclosure; 
           [0039]      FIG. 16  is a diagram illustrating an example of a multi subframe setting operation of a base station according to an embodiment of the present disclosure; 
           [0040]      FIG. 17  is a diagram illustrating an example of a multi subframe setting operation of a terminal according to an embodiment of the present disclosure; 
           [0041]      FIG. 18  is a diagram illustrating an example of uplink (UL) multi subframe assignment and a transmission thereof according to an embodiment of the present disclosure; 
           [0042]      FIG. 19  is a diagram illustrating an example of a UL multi subframe assignment and a transmission and a retransmission thereof according to an embodiment of the present disclosure; 
           [0043]      FIG. 20  is a diagram illustrating an example of a UL multi subframe assignment and a transmission and a retransmission thereof according to an embodiment of the present disclosure; 
           [0044]      FIG. 21  is a diagram illustrating a configuration of a terminal according to an embodiment of the present disclosure; and 
           [0045]      FIG. 22  is a diagram illustrating a configuration of a base station according to an embodiment of the present disclosure. 
       
    
    
       [0046]    Throughout the drawings, it should be noted that liked references numbers are used to depict the same or similar elements, features, and structures. 
       DETAILED DESCRIPTION 
       [0047]    The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness. 
         [0048]    The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents. 
         [0049]    It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces. 
         [0050]    For the same reason, some components are exaggerated, omitted, or schematically illustrated in the accompanying drawings. Further, the size of each component does not exactly reflect its real size. In each drawing, the same or corresponding components are denoted by the same reference numerals. 
         [0051]    Further, it may be understood that each block of processing flowcharts and combinations of flowcharts may be performed by computer program instructions. Since these computer program instructions may be mounted in processors for a general computer, a special computer, or other programmable data processing apparatuses, these instructions executed by the processors for the computer or the other programmable data processing apparatuses create means performing functions described in block(s) of the flowcharts. Since these computer program instructions may also be stored in a computer usable or computer readable memory of a computer or other programmable data processing apparatuses in order to implement the functions in a specific scheme, the computer program instructions stored in the computer usable or computer readable memory may also produce manufacturing articles including instruction means performing the functions described in block(s) of the flowcharts. Since the computer program instructions may also be mounted on the computer or the other programmable data processing apparatuses, the instructions performing a series of operation operations on the computer or the other programmable data processing apparatuses to create processes executed by the computer to thereby execute the computer or the other programmable data processing apparatuses may also provide operations for performing the functions described in block(s) of the flowcharts. 
         [0052]    In addition, each block may indicate some of modules, segments, or codes including one or more executable instructions for executing a specific logical function(s). Further, it is to be noted that functions mentioned in the blocks occur regardless of a sequence in some alternative embodiments. For example, two blocks that are consecutively illustrated may be simultaneously performed in fact or be performed in a reverse sequence depending on corresponding functions sometimes. 
         [0053]    Herein, the term ‘˜unit’ used in the present embodiment means software or hardware components such as a field-programmable gate array (FPGA) and an application specific integrated circuit (ASIC) and is responsible for any role. However, the meaning of the ‘˜unit’ is not limited to software or hardware. The ‘˜unit’ may be configured to be in a storage medium that may be addressed and may also be configured to reproduce one or more processor. Accordingly, for example, the ‘˜unit’ includes components such as software components, object oriented software components, class components, and task components and processors, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuit, data, database, data structures, tables, arrays, and variables. The functions provided in the components and the ‘˜units’ may be combined with a smaller number of components and the ‘˜units’ or may further be separated into additional components and ‘˜units’. In addition, the components and the ‘˜units’ may also be implemented to reproduce one or more CPUs within a device or a security multimedia card. 
         [0054]    In describing specific embodiments of the present disclosure in detail, a wireless communication system having a particular channel structure will be mainly described, but the subject matter to be claimed in the present specification may be also applied to other communication systems and service having the similar technical backgrounds as long as it does not depart from the scope and spirit of the present specification, which may be made by the determination of a person having ordinary skill in the art to which the present disclosure pertains. 
         [0055]    Prior to a description of embodiments of the present disclosure, an example of an interpretable meaning for some terms used herein is provided. However, it should be noted that the present disclosure is not limited to the interpretation examples given below. 
         [0056]    A base station (BS) which is a subject communicating with a terminal may be referred to as a BS, a base transceiver station (BTS), a node B (NB), an evolved NB (eNB, eNodeB), an access point (AP), a 5th-generation (5G) NB (gNB), or the like. In particular, at least one of the following embodiments of the present disclosure may be implemented in a heterogeneous network (HetNet) made up of a primary base station and an auxiliary base station, in which the primary base station may be referred to as a macro BS, a primary BS, a primary cell (PCell), or the like and the auxiliary base station may be referred to as a small BS, a secondary BS, a secondary cell (SCell), or the like. 
         [0057]    User equipment (UE) which is one subject communicating with a base station may be referred to as a UE, a device, a mobile station (MS), mobile equipment (ME), a terminal, etc. 
         [0058]    In order to improve the speed and capacity of the long term evolution (LTE) network with the development of the LTE, improved technologies such as LTE in unlicensed spectrum (LTE-U) using a shared band are being studied. The LTE-U or the licensed-assisted access (LAA) means a technology of integrating not only licensed bands used for the existing LTE communications but also licensed spectra or licensed bands and unlicensed spectra an unlicensed bands using carrier aggregation (CA). Accordingly, it is possible to support quality of service (QoS) and smooth mobility by using a more stable licensed band as an anchor to process all control signals and signaling. In addition, it is possible to give users with more improved mobile broadband experience by ensuring a boarder data pipe by extension to the unlicensed band. 
         [0059]    Since the unlicensed band is a shared band that may be used by any technologies and devices, most countries specify transmission regulations to use the unlicensed band. In order to reduce device to device interference in the unlicensed band, transmit power of devices using the unlicensed band may be limited to a level lower than that of the licensed band. 
         [0060]    The transmission regulations for shared bands such as a license-exempt band or the unlicensed band provide various schemes for relieving the device to device signal interference. As an example, the schemes may include a scheme of limiting transmit power so that receive power at a certain distance is not equal to or greater than a predetermined value, a scheme of hopping locations on time or frequency resources, a scheme of using only a certain resource among the entire resources, a scheme of first hearing signals from other devices and then restrictively performing a transmission only when receive power of the signal is smaller than a predetermined value, or the like. 
         [0061]    The existing cellular communications such as the LTE requires a channel measurement for adaptively determining transmission capacity of a transmitting/receiving link and a resource assignment procedure based on link adaptation. However, there may be problems in applying the existing resource assignment schemes in the shared bands such as the unlicensed band where rules for coexistence between different communication systems are established. Therefore, there is a need for a new resource assignment scheme for communications using an unlicensed band. 
         [0062]    Meanwhile, in a HetNet, the terminal may transmit and receive main system information (SI) and a control signal and may communicate mobility-sensitive traffic like a sound with the PCell and communicate traffic like data, which makes much of instantaneous transmission amount, with the SCell. Here, the Pcell may be set as the licensed band, and the SCell may be set as the shared band, that is, the unlicensed band. An example of the type of cellular communication system may include the LAA system. A terminal that additionally uses the shared band may be referred to as an LAA terminal and a terminal that uses only the existing licensed band may be referred to as an LTE terminal. 
         [0063]    A terminal in a base station area may be in a radio resource control (RRC) idle state or an RRC connected state. The two states will be described below.
       RRC IDLE: The RRC idle state is a state in which the terminal selects the base station (or cell), monitors a paging channel, and acquires SI but does not communicate data with the base station. It is considered that the terminal is camped in the corresponding base station.   RRC CONNECTED: The RRC connected state is a state in which the terminal monitors a control channel and communicates data with the base station through a data channel. It is a state in which the terminal reports various measurement results of the base station and neighbor base stations to help scheduling of the base station. The terminal is served with a service from the corresponding base station. Further, the corresponding base station is referred to as a serving cell for a serving terminal.       
 
         [0066]    Equipment using the unlicensed band is classified into frame based equipment (FBE) or load based equipment (LBE). Hereinafter, a communication procedure by each equipment will be described. 
         [0067]      FIG. 1  is a diagram showing an example of a communication procedure through an unlicensed band in the case of FBE according to an embodiment of the present disclosure. 
         [0068]    Referring to  FIG. 1 , in the case of FBE, a transmitter needs to perform clear channel assessment (CCA)  110  above at least 20 micro seconds (μs) prior to performing a transmission  120  over an unlicensed band. The CCA  110  performs an operation of determining, by a transmitter, a magnitude of interference to determine whether another equipment currently uses an unlicensed band. The transmitter does not perform a transmission if it is determined as a result of the CCA  110  that the measured magnitude of interference is equal to or greater than a predetermined value, but performs the transmission  120  if it is determined as a result of the CCA  110  that the measured magnitude of interference is less than the predetermined value. At this point, the transmission  120  has a fixed frame period  140  and starts a start point of a frame immediately following a CCA period. If the transmitter performs the CCA  110  once, the transmitter may occupy an unlicensed band from at least 1 ms up to 10 ms and should be idle during an idle period  135  without performing the transmission for at least 5% of channel occupancy time (COT)  130 . If it is determined as the performance result of the CCA  110  of the transmitter that another equipment currently uses an unlicensed band, the transmitter may pass through the fixed frame period  140  and then perform the CCA  115  again. 
         [0069]      FIG. 2  is a diagram showing an example of a communication procedure through an unlicensed band in the case of LBE according to an embodiment of the present disclosure. 
         [0070]    Referring to  FIG. 2 , like the FBE, in the case of LBE, the transmitter performs the CCA  110  for at least 20 μs prior to performing the transmission  120  through the unlicensed band. If it is determined as the performance result of the CCA  110  that there is no equipment currently using the unlicensed band, the transmitter may perform the transmission  120 . However, if it is determined that another equipment is currently using the unlicensed band, unlike the FBE, the LBE may perform an additional CCA that is referred to as extended CCA (ECCA)  150 . The ECCA  150  consists of N CCAs  111 ,  112 ,  113 , and  114 , in which N is a backoff counter value (T ECCA )  160  arbitrarily selected between [1, q] and q represents a contention window size (CWS). The CWS q may be given by the base station or may be determined by the terminal.  FIG. 2  illustrates the case where N is 4, in which N may be smaller or larger than 4. An N CCA counter is decremented each time one of the CCAs  111 ,  112 ,  113 , and  114  succeeds. If the CCA counter detects a band occupancy before it reaches 0, a freezing operation waiting until the band occupancy is resolved while the CCA counter is stored is performed. If it is detected that band use is possible again, an operation of decreasing the CCA counter restarts again. When the CCA counter reaches 0, if it is determined that there is no equipment currently using an unlicensed band, the transmitter performs the transmission  120  after the last CCA interval. That is, if it is determined as the performance result of the ECCA  150  that there is no equipment currently using the unlicensed band, the transmitter may perform the transmission  120 . At this point, the time when the transmitter may occupy the unlicensed band, that is, the COT  130 , is up to ( 13/32)*q ms and then the CCA  115  may be performed again and the transmitter has the idle period  135  for the time when the ECCA is performed. 
         [0071]    Meanwhile, the FBE and the LBE each have advantages and disadvantages. First, the performance of the LBE will show better than that of the FBE, in view of the occupancy probability of the unlicensed band. This is because the FBE may not perform the CCA again for a fixed frame period  140  if the CCA  110  fails once but the LBE may take an operation to occupy the unlicensed band by performing the ECCA  150 , that is, an additional CCA ( 111 ,  112 ,  113 , and  114 ) N times after the CCA  110  fails. 
         [0072]    Next, there is an advantage that the FBE is simpler than the LBE in view of the scheduling, that is, the transmission of the control channel. The FBE may use the unlicensed band based on a subframe boundary, that is, control channel (PDCCH) transmission time point. However, since the LBE arbitrarily selects N which is the CCA performance frequency of the ECCA  150 , the use start time point of the unlicensed band may not match the subframe boundary. Therefore, the LBE reserves a part of a first subframe and performs a transmission of a control channel and a data channel from a second subframe. 
         [0073]    In addition, the FBE does less damage to neighboring Wi-Fi devices sharing an unlicensed band, compared to the LBE. Generally, the LBE is more likely to occupy the unlicensed band than the FBE. This is because the Wi-Fi device is taking more chances to occupy the unlicensed band. In the 3GPP standard, the FBE scheme is referred to as CAT2 LBT and the LBE scheme is referred to as CAT4 LBT. 
         [0074]    Meanwhile, in order to provide a reliable cellular communication service in the mobile environment even if an unlicensed band is used, the terminal needs a scheme for maintaining an access to a licensed band. Therefore, delay-sensitive services such as voice may be transmitted in the licensed band, and data services may be transmitted using the licensed band and opportunistically, may be transmitted using the unlicensed band, thereby improving the data transmission rate as much as possible. 
         [0075]      FIG. 3  is a diagram illustrating a procedure for determining transmission capacity of a transmitting/receiving link in a wireless communication system according to an embodiment of the present disclosure. 
         [0076]    Referring to  FIG. 3 , in a downlink, a terminal  310  measures a reference signal (RS)  332  of a base station  320  and carries a signal quality of the RS on a channel quality indicator (CQI)  334  and report it to the base station  320 . The RS  332  of the base station  320  may consist of a common/cell-specific reference signal (CRS) or a channel state information-reference signal (CSI-RS) commonly given to all terminals  310  within a service area of the base station  320  or a UE-specific RS given only to a specific terminal  310 . The terminal  310  may be controlled by the base station  320  to periodically or a periodically report the CQI  334  indicating channel quality to the base station  320 . The terminal  310  may use a physical uplink control channel (PUCCH) for the periodic report and a physical uplink shared channel (PUSCH) for the aperiodic report. 
         [0077]    According to an embodiment, the CRS may be replaced with a synchronization signal (SS). 
         [0078]    The base station  320  may perform scheduling for determining to which one of the terminals  310  physical resource blocks are assigned based on the CQI  334  that the terminal  310  reports and notify ( 336 ,  338 ) the scheduled terminals  310  of assignment information for each terminal as the scheduled result. Resource assignment signals (or referred to as uplink (UL) grant/downlink (DL) grant) signal indicating an assigned downlink resource location and resource assignment information (e.g., physical channel parameters such as modulation and coding scheme (MCS) index and hybrid automatic repeat request (HARQ) related information) may be scrambled with identification of the terminal  310 , for example, a cell radio network temporary identity (C-RNTI) or an M-RNTI (mobile broadcast service (MBMS) RNTI) and may be transmitted through a physical downlink control channel (PDCCH). The terminal  310  receiving the resource assignment signal may receive (downlink data  340  on a physical downlink shared channel (PDSCH) through the physical resource blocks notified by the resource assignment signal. 
         [0079]    In case of the uplink, the base station  320  may measure the RS from the terminal  310  and know the quality of the uplink signal. The RS of the terminal  310  may use a sounding reference signal (SRS) that the base station  320  periodically assigns (about 2 to 320 ms) to a specific UE. Even if it differs from the current standard, a demodulation reference signal (DMRS) that the terminal  310  transmits together with the uplink data may be used for the uplink measurement of the unlicensed band for the operation in the shared band. The base station  320  performs the uplink scheduling for determining to which one of the terminals  310  the physical resource blocks are assigned based on the CQI obtained by measuring the RS that the terminal  310  transmits and notifies the scheduled terminals  310  of the assignment information for each terminal as the scheduling result. The resource assignment signal indicating the assigned uplink resource is scrambled with the identification of the terminal  310  and transmitted through the PDCCH, and the terminal  310  receiving the resource assignment signal may transmit the uplink data on a PUSCH through the physical resource blocks notified by the resource assignment signal. 
         [0080]    For the base station  320  to complete the channel measurement and the link adaptation for the terminal  310 , a predetermined delay time is taken due to the transmission and reception and processing of required signals. For example, reviewing the operation of the downlink illustrated in  FIG. 3 , the terminal  310  measures the RS  332  (e.g., CRS) that the base station  320  transmits every downlink subframe, and two subframes are required to report the CQI  334 , by the terminal  310 , through the physical uplink control channels (PUCCHs) assigned to each uplink subframe. The base station  320  requires one subframe for channel estimation  336 , and requires one to k subframes  338  according to implementation of scheduling for determining the resource assignment and the MCS index. Therefore, a minimum allowable CQI feedback delay  342  may be 4 ms. 
         [0081]    Since the minimum period of the SRS in the uplink is 2 subframes, the uplink more generates one subframe delay than the downlink, and thus the CQI feedback delay is at least 5 ms. The longer the SRS period, the longer the overall CQI feedback delay. 
         [0082]    In the unlicensed band, since the terminal  310  performs the LBT prior to transmitting the uplink signal and performs the transmission when the result is successful (i.e., channel is empty), the transmission failure probability is higher than the existing licensed band. To overcome the above problems, a scheme for assigning a redundant resource is required. Also, there is a need to design an appropriate resource assignment scheme differently depending on data or a control signal. 
         [0083]    In the embodiments described below, a resource assignment scheme for minimizing a loss will be described in consideration of the three problems described above. 
         [0084]    That is, since it is difficult to perform the periodic channel measurement, the terminal  310  may perform the CQI report based on the channel measurement value after the base station  320  successfully performs the LBT and occupies the channel. For this, the base station  320  may assign to the terminal  310  resources of subframes that are temporally close to each other. 
         [0085]    A delay of at least 4 ms in the downlink and a delay of at least 5 ms in the downlink may occur even if the aperiodic channel measurement is assumed. For example, therefore, in the case of the downlink, the CQI measured in the first subframe may be reflected to the scheduling only when the COT is greater than at least 4 ms. As a result, since the base station  320  may not perform the correct CQI based MCS determination on four subframes for the first 4 ms, the base station may select a complementary MCS index for the subframes. 
         [0086]    In addition, if the terminal  310  fails to perform the LBT, that is, if a channel busy is detected, the terminal  310  needs to receive the resource assignment from the base station  320  again. At this time, a delay of 7 ms may occur in order of a scheduling request (SR), an interval of 3 ms, UL grant, an interval of 4 ms, and a data transmission. Therefore, if it is determined that an LBT failure rate is high, the base station  320  may assign resources for consecutive subframes by one-time grant. 
         [0087]      FIG. 4  is a diagram illustrating an example of a downlink scheduling procedure according to an embodiment of the present disclosure. 
         [0088]    Referring to  FIG. 4 , in operation  410 , the base station (eNB)  320  transmits the physical channel parameters (e.g., MCS index or the like) assigned by the scheduling and the downlink resource information (DL resource information) indicating the assigned resources to the terminal (UE) through the PDCCH. In operation  420 , the base station  320  may transmit user data to the terminal  310  through the PDSCH on the physical resource blocks indicated by the downlink resource information. In operation  430 , the terminal  310  may transmit to the base station  320  acknowledgment (ACK)/non-ACK (NACK) that is a HARQ response to the user data. At this point, a delay of 4 ms may occur between the user data of the downlink and the ACK/NACK. If the HARQ response in the operation  430  is the NACK, in operation  440 , the base station  320  may retransmit the user data to the terminal  310 . 
         [0089]      FIG. 5  is a diagram illustrating an example of an uplink scheduling procedure according to an embodiment of the present disclosure. 
         [0090]    Referring to  FIG. 5 , in operation  510 , the terminal  310  having the user data or the control information to be transmitted to the uplink may transmit the SR to the base station  320  through the PUCCH. The base station  320  performs the scheduling in response to the SR, and in operation  520 , may transmit the uplink grant according to the scheduling, that is the uplink resource information, to the terminal  310  through the PDCCH. The scheduling may take, for example, 3 ms. In operation  530 , the terminal  310  may transmit the user data, a buffer status report (BSR), a power headroom report (PHR) or the like through the PUSCH on the physical resource block indicated by the uplink resource information. In this case, it may take 4 ms to prepare the uplink transmission through the PUSCH. In operation  540 , the base station  320  may transmit the ACK/NACK for the uplink reception through the PUSCH to the terminal  310  through a physical HARQ indication channel (PHICH). At this point, a delay of 4 ms may occur between the uplink transmission through the PUSCH and the ACK/NACK of the base station. 
         [0091]    Therefore, a method according to an embodiment of the present disclosure is a method for assigning a resource in a cellular network using an unlicensed band. The method includes generating, by a base station, at least one resource assignment signal including information indicating a plurality of consecutive uplink subframes transmittable and receivable through an unlicensed band, transmitting the resource assignment signal to a terminal through the unlicensed band during at least one resource subframe, and receiving an uplink data from the terminal during the consecutive uplink subframes. 
         [0092]    Further, a method according to an embodiment of the present disclosure is a method for receiving resource assignment in a cellular network using an unlicensed band. The method includes receiving, by a terminal, at least one resource assignment signal including information indicating a plurality of consecutive uplink subframes transmittable and receivable through the unlicensed band from a base station during at least one downlink subframe, identifying the plurality of consecutive uplink subframes based on the resource assignment signal and other control signals, and transmitting uplink data to the base station during the consecutive uplink subframes. 
         [0093]    Further, an apparatus according to an embodiment of the present disclosure includes a base station for assigning a resource in a cellular network using an unlicensed band. The base station includes at least one processor generating at least one resource assignment signal including information indicating a plurality of consecutive uplink subframes transmittable and receivable through the unlicensed band, and a transceiver transmitting the resource assignment signal to a terminal through the unlicensed band during at least one resource subframe and receiving uplink data from the terminal during the consecutive uplink subframes. 
         [0094]    Further, an apparatus according to an embodiment of the present disclosure includes a terminal for receiving a resource assignment signal in a cellular network using an unlicensed band. The terminal includes a transceiver receiving at least one resource assignment signal including information indicating a plurality of consecutive uplink subframes transmittable and receivable through the unlicensed band from a base station during at least one downlink subframe and transmitting uplink data to the base station during the consecutive uplink subframes, and at least one processor identifying the plurality of consecutive uplink subframes based on the resource assignment signal and other control signals, and transmitting uplink data and notifying the transceiver of the identified subframes. 
         [0095]    Further, an apparatus according to an embodiment of the present disclosure includes a terminal for receiving a resource assignment signal for transmission of a control signal in a cellular network using an unlicensed band. The terminal includes a transceiver receiving at least one resource assignment signal including information indicating a plurality of consecutive uplink subframes transmittable and receivable through the unlicensed band from a base station during at least one downlink subframe and transmitting an uplink control signal to the base station during the consecutive uplink subframes and at least one processor identifying the plurality of uplink subframes based on the resource assignment signal and other control signals, and transmitting uplink data and notifying the transceiver of the identified subframes. 
         [0096]    Meanwhile, although the procedures, methods, and apparatuses of the present disclosure are described below with respect to the unlicensed band, they may be applied in the licensed band, the shared band, and the like without any restrictions. 
       Transmission of Uplink Control Signal 
       [0097]    The base station  320  may assign a control channel or data channel resource in order to allow the terminal  310  to transmit the uplink control information (UCI). In case of the LTE, the base station  320  may transmit UCI to the terminal  310  through the PUCCH (uplink control channel) or may multiplex the UCI with data through the PUSCH (uplink shared channel) and transmit it to the terminal  310 . As the method for assigning an uplink resource in the unlicensed band, there may be largely cross-carrier (CC) scheduling and self-carrier (SC) scheduling. According to the CC scheduling, the base station  320  may assign an uplink resource of an unlicensed band SCell2 through a downlink control channel in the PCell or the SCell1. According to the SC scheduling, the base station  320  may assign an uplink resource of the same SCell2 through a downlink control channel in the unlicensed SCell2. 
         [0098]    In this case, if the PCell or the SCell1 is the licensed band, the CC scheduling is not affected by the LBT. However, if the PCell or the SCell1 is the unlicensed band, even the CC scheduling is affected by the LBT for the downlink control channel transmission. The SC scheduling is naturally affected by the LBT for the downlink control channel transmission. Therefore, if the downlink control channel is transmitted in the unlicensed band, the LBT having a high success rate needs to be applied to the uplink resource assigned to the terminal  310 . In this case, the LBT having a high success rate means a case where CAT2 LBT (FBE) is used or a backoff counter or a contention window value of CAT4 LBT (LBE) is small. 
         [0099]    Meanwhile, a delay of 4 ms is typically required between the UL grant and the UL data. This occurs because the terminal  310  receives an instruction from the base station  320 , encodes a packet to be transmitted, or requires a calculation time to determine transmit power. Several advantages may be obtained by reducing the delay time between the UL grant and the UL data in the unlicensed band. First, when the LBT fails, the total delay taken until the terminal  310  receives the UL grant again and transmits data may be reduced. Further, the SC scheduling may reduce an empty period until the terminal  310  transmits resources after the base station  320  occupies the resources, thereby more efficiently using the resources. 
         [0100]    Further, since the transmission period of various UL control information and UL data is set differently, there is a need to be able to support various resource assignment methods by a minimum possible UL grant overhead. 
         [0101]    Meanwhile, in order to cope with the LBT failure in the unlicensed band, multi subframe scheduling capable of resource assignment for a plurality of UL subframes by one-time UL grant may be considered. This is mainly considered for the data transmission and may increase the success rate by assigning k consecutive UL subframes to allow the terminal  310  to perform the LBT on the k consecutive UL subframes. Further, the UCI information may be considered in a different scheme from data depending on its format. 
         [0102]    For a channel state indication (CSI) report for the channel measurement result, a report period may be set in subframe units of {2, 5, 10, 20, 40, 80, 160, 32, 64, 128}. If the report period has a relatively smaller value, like data, a CSI report resource may be indicated by the UL grant but if the report period has a relatively larger value, it may exceed an area in which the UL grant may be indicated. Further, if the report period has a larger value, a strict report period that needs to be notified by the UL grant is not required. Therefore, if the report period is set by a higher layer message (e.g., RRC message) for the CSI report, it may be understood that the terminal  310  assigned at least one UL subframe by the UL grant in the set CSI [within the report period], [report period−delta, report period], [report period−delta, report period+delta], or [report period, report period+delta] and the terminal  310  performs the CSI report in the first UL subframe among them. The delta value may be set to a predetermined value or a preset ratio or may be set by the base station  320 . The reason of setting the delta value is to reduce a burden of the base station  320  that should perform a blind detection on whether the terminal  310  transmits the CSI information or not at any location within the report period. 
         [0103]    In the case of the existing licensed band, the PUCCH locations are fixed on a terminal-by-terminal basis, such that the terminal  310  may adequately report the CSI by the report period information. However, in the case of the unlicensed band, the terminal  310  may access resources at any time point and therefore to prevent report signals of different terminals from colliding with each other, an offset of the report period and a report resource period needs to be additionally set along with the report period. It is understood that the terminal  310  sets report resources at each report resource period from the set offset on, for example, SFN #0, and the terminal  310  may perform a one-time CSI report in a period divided depending on the report period. The report resource period may be set to be, for example, 5 ms, and the report period may be set to be, for example, 20 ms. Different terminals  310  may be assigned the report resources divided by the offset, the report resource period, and a resource block (RB). At this point, the RB may be set by the RRC message or dynamically by the UL grant. 
         [0104]    Unlike the CSI report, the resource for the HARQ-ACK report is generally assigned to the PUCCH or the PUSCH of the UL subframe after 4 ms for DL data. By the way, since there is no guarantee that the LBT will succeed after 4 ms in the unlicensed band, redundant UL resources need to be assigned. At this point, the redundant UL resources may be further assigned to a time axis or a frequency (component carrier) axis. The base station  320  may assign resources for HARQ-ACK report to consecutive UL subframes, like the multi subframe UL grant method. If there are UL data, the base station  320  may control a UCI control signal including HARQ-ACK to be multiplexed with the UL data and transmitted. 
         [0105]    Further, if the HARQ-ACK report resource is assigned to a plurality of UL subframes by the base station  320 , it is preferable that HARQ-ACK report resource is assigned to all of the plurality of UL subframes indicated by the UL grant. If the HARQ-ACK is reported in a first succeeding UL subframe among the plurality of UL subframes, the terminal  310  needs to simultaneously perform an operation of configuring a signal having only the UL data in the subsequent UL subframe according to whether the LBT of the current UL subframe succeeds and an operation of configuring a signal obtained by multiplexing the HARQ-ACK with the UL data. However, if the HARQ-ACK resource is assigned to all of the plurality of UL subframes, resources are used inefficiently. Further, since a timing interval between the DL data and the HARQ-ACK is not fixed, the reception complexity of the base station  320  may be increased. To avoid this, a method of assigning a redundant UL subframe to a component carrier axis may be considered. For example, if the base station  320  sets a UCI cell group in the terminal  310 , the terminal  310  transmits HARQ-ACK feedback from at least one of the SCells, which successfully perform the LBT, among the UL subframes for each SCell corresponding to HARQ-ACK timing defined within the UCI cell group. At this point, if the LBT succeeds in a plurality of SCells, 1) the terminal  310  may report the HARQ-ACK feedback in all the SCells. Further, 2) the terminal  310  may compress and report the HARQ-ACKs for a plurality of CCs in the SCell having the lowest SCell index. Further, 3) if all LBTs succeed at CC above the maximum concurrent transmission CC (e.g., three (or two or four or more)), the terminal  310  may report the HARQ-ACK only up to the maximum concurrent transmission CC while the SCell index is increased from CC having the lowest SCell index, for example. Further, for the SCell exceeding the maximum concurrent transmission CC, the transmission is not performed even if the LBT succeeds, it may be considered as discontinuous transmission (DTX) or LBT failure to be operated. Meanwhile, if the terminal  310  reports the plurality of HARQ-ACKs at any one of the CCs, the same format as the existing UCI format 3 accommodating the HARQ-ACK for the DL data of other CCs may be used. 
         [0106]    As described above, the 4 ms delay between the UL grant and the UL data transmission may have a big effect on performance. Therefore, a scheme for reducing 4 ms delay will be described. The largest operation required for the terminal to receive the UL grant and prepare the UL data is to encode information bits and to determine transmit power. Therefore, if the base station  320  notifies the terminal  310  of the resource assignment information (transport block (TB) size, MCS, RB assignment, hopping, etc.) in advance, the terminal  310  may configure the transmission data in advance and respond to the fast UL grant of the base station  320  to reduce the delay between the UL grant and the UL data transmission. A transmit power control command is to progressively change transmit power, and therefore needs to be transmitted like every UL grant but may be controlled to use the same transmit power for a plurality of assigned subframes. For setting the resource assignment information in the terminal  310 , the base station  320  may semi-statically transmit the RRC message including the resource assignment information to the terminal  310  or may dynamically transmit an uplink resource grant (UL resource grant) including the resource assignment information to the terminal  310 . If the data to be transmitted is prepared, the terminal  310  previously receiving the resource assignment information may transmit the UL data having a short delay time (e.g., about 1 ms or the like) to a fast UL grant. Meanwhile, if the base station  320  starts to occupy resources by the CAT4 LBT, it may perform consecutive transmission and reception using a fast LBT within a maximum channel occupancy time (MCOT) period that is defined depending on traffic priority. That is, if the number of DL subframes and the number of UL subframes is included in the MCOT, the base station  320  or the terminal  310  may perform the fast LBT depending on the short CCA (e.g., 25 μs) or the small backoff (BO) counter value upon the transmission within the period. 
         [0107]    In the operation of the base station  320  and the terminal  310  based on the resource assignment information and the fast UL grant, the following operations may be made depending on when the terminal  310  prepares a transmission packet and when the terminal  310  transmits a packet. 
         [0108]    1) When the Fast UL Grant Includes Transmission Time Point: 
         [0109]    After receiving a message (e.g., RRC message or UL resource grant) including resource assignment information, the terminal  310  may start to prepare a data packet to be transmitted to the base station  320  on the uplink. Further, after a delay time of at least 3 ms, the base station  320  may transmit a fast UL grant to the terminal  310 . At this point, the base station  320  implicitly instructs the terminal  310  to use the fast UL grant to implicitly indicate a minimum delay (e.g., 1 ms), or explicitly assigns delay information of m subframe intervals by including the delay information in the fast UL grant. 
         [0110]    In this case, the terminal  310  should be always prepared to transmit the next data packet immediately after completing a transmission of one data packet. Accordingly, if the terminal  310  is not prepared, for the base station  320  to transmit the fast UL grant to the terminal  310 , the base station  320  may notify the terminal  310  of the number of TBs to be prepared in advance, in addition to the resource assignment information. 
         [0111]    In addition, the method controls the transmission time point of each terminal by the UL fast grant. For preventing the collision of the LBT with each terminal and for coexistence with other systems, a method of notifying the same transmission time point to the UE group may be considered additionally. The C-RNTI may be shared or the N-RNTI may be assigned to indicate the UE group. The method may be applied to both consecutive assignment and discontinuous assignment. For example, in the case of the consecutive assignment, [0, 1, 2] or [0, 2] or [2] may be transmitted to indicate n+1, n+2, and n+3 from an n subframe in which the fast grant is transmitted. In the case of the discontinuous assignment, [0, 2, 4] may be transmitted to indicate n+1, n+3, and n+5 from the n subframe in which the fast UL grant is transmitted. As another method, [0, 1, 2], [0, 2], or [2] may be transmitted, but an inter-subframe interval may be indicated by a separate individual/common control signal. For example, if the inter-subframe interval is indicated by 2, [0, 1, 2] may be understood as n+1, n+3, and n+5. 
         [0112]    Meanwhile, the terminal  310  may prepare an initial transmission packet in advance, but in the case of the uplink retransmission, the terminal may not prepare a retransmission packet in advance unless the base station  320  notifies the terminal  310  of the HARQ-ACK/NACK. In synchronous HARQ, the base station  320  may notify the terminal  310  of the HARQ-ACK/NACK through the physical Hybrid-ARQ indicator channel (PHICH) after 4 ms after transmitting the UL data. However, if the base station  320  does not transmit the PHICH to the licensed band, it is difficult to accurately keep the interval of 4 ms. The reason is that a resource access is stochastically defined depending on the success or failure of the LBT of the base station  320  in the unlicensed band. Further, the PHICH uses only a synchronous HARQ procedure in the uplink. In the unlicensed band, only the asynchronous HARQ procedure may be considered due to uncertainty of an uplink resource access. Therefore, the following schemes may be considered. 
         [0113]    a) HARQ-ACK/NACK for Uplink: 
         [0114]    The base station  320  may transmit separate HARQ-ACK information to the terminal  310 , in addition to the UL grant. For example, if the UL data is assigned at locations n, n+1, . . . , n+k in k multi subframes, the base station  320  may transmit the HARQ-ACK to the terminal  310  at locations n+4, n+5, . . . , n+k+4 if the downlink LBT succeeds. In addition, if the base station successfully performs the downlink LBT, the base station  320  may transmit the HARQ-ACK even at locations n+k+5, n+k+6, . . . , n+2k+5. This generally corresponds to the case where locations of resources having m values at locations m+0, m+1, . . . m+k are repeated every n+4, n+4+k, . . . N+4+p*k. The base station  320  may perform the uplink operation at the corresponding location or excludes the situation where it does not secure the resource due to the failure of the LBT, secure the downlink subframe if the LBT succeeds, and immediately transmit the HARQ-ACK for the PUSCH transmission of the unlicensed band to the terminal  310  with the HARQ-ACK before the subsequent UL grant is transmitted. 
         [0115]    b) Identification by NDI: 
         [0116]    If the HARQ-ACK for the UL data is not fed back to the terminal  310 , the terminal  310  is applied with the fast UL grant of about 1 ms for the initial transmission, but cannot but suffer from a general delay of 4 ms for the retransmission. In order to reduce the delay, the terminal  310  should prepare both the initial transmission and the retransmission packet but the complexity of the terminal  310  may be increased. If the terminal  310  identifies and transmits any one the initial transmission and the retransmission, the base station  320  may transmit the UL grant including the NDI information. The NDI information is generally transmitted in a toggling manner, compared to the previous NDI information. That is, if the previous NDI is 0, it is changed to 1 and if the previous NDI is 1, it is changed to 0 to notify that it is a new packet. Therefore, if the NDI is toggled for the same transmission time point information, for example, [0, 1, 2], that is, if the initial transmission is performed, the terminal  310  may transmit a packet that is being prepared in advance in n+1, N+2, and n+3 subframes, compared to the n subframe that is the UL grant reception time point. Conversely, if the NDI is not toggled, that is, if the retransmission is performed, the terminal  310  prepares a new retransmission packet and transmits it in n+4, n+5, and n+6 subframes. On the other hand, due to the interference among the causes of the retransmission, there may be the case where the base station  320  fails to receive the PUSCH but there may be the case where the terminal fails to perform the LBT. If the terminal  310  fails to perform the LBT, exceptionally, the fast UL grant is possible again. In order for the terminal  310  to identify the NDI, the base station  320  may 1) toggle the NDI in the UL grant but change a redundancy version (RV) to a value different from an RV value transmitted at the time of the initial transmission and transmit it, 2) transmit the RV redundancy at the same RV value as the previous value without toggling the NDI, or 3) transmit the RV redundancy so that a transmit power change value is 0 in a UL TPC command. 
         [0117]    c) Identification by Transmission Time Point Information: 
         [0118]    The base station  320  may indicate the initial transmission by [3, 4, 5] and the retransmission by [ 0 ,  1 ,  2 ] and indicate time point {n+4, n+5, n+6} and {n+1, n+2, n+3} compared to the UL grant time point (n). Alternatively, the fast delay transmission is indicated by [0, 1, 2], 0 and the general delay transmission is indicated by [0, 1, 2], 1 and thus the UL grant-UL data delay is identified by a last bit, such that compared to the UL grant time point (n), the time point {n+4, n+5, n+6} and the time point {n+1, n+2, n+3} may be indicated. In case of the identification by the transmission time point information, the proper UL grant may be combined with the NDI information to control the retransmission due to the initial transmission and the reception error, and the retransmission due to the LBT failure. For example, if the NDI is toggled and the fast delay transmission is performed, it may correspond to the initial transmission. If the NDI is not toggled and is the general delay transmission, it is the retransmission due to the reception error. If the NDI is not toggled and the fast delay transmission is performed, it may be the retransmission due to the LBT. 
         [0119]    2) If Transmission Time Point is Included in Resource Assignment Information: 
         [0120]    If the terminal  310  receives the resource assignment information (e.g., RRC message or UL resource grant) or a separate common control signal, the terminal  310  may additionally know the transmission time point (e.g., subframe timing, or the like) in addition to the TB size, the MCS, the RB assignment, and hopping. Further, the terminal  310  may start to prepare the data transmission 4 ms ahead of the scheduled nearest transmission time point. The advantage of the method is that if the transmission time point is set to be a long period, there is no need to perform the unnecessary processing and the use of the memory in advance. In addition, since periodically available resources are designated over a long period of time, there is no need to issue a separate UL grant for the retransmission. For example, if the scheduled transmission time point is set at an interval of 8 ms and the data generation delay of the terminal  310  is set to be 4 ms in the RRC configuration, the terminal  310  may be prepared to generate data in advance before 4 ms, compared to each transmission time point. If the fast UL grant of the base station  320  is received in 4 ms, the terminal  310  transmits the prepared data and if the fast UL grant is not received until the transmission time point, the terminal  310  may not perform the transmission at the transmission time point. Further, if the terminal  310  does not receive the fast UL grant for the scheduled transmission time point, that is, the subframe, the terminal  310  may consider the subframe as a downlink subframe and perform a signal reception operation of the base station  320 .
       In the LBT method for the UCI and the uplink data, intervals between a plurality of UL subframes may be set to be different from each other. For example, resources may be assigned in a t subframe period for the UCI transmission. On the other hand, resources may be assigned in a t′ subframe for the data transmission. At this point, t may use a value equal to or greater than t′. For example, if t′ is 1, the success rate of the data transmission may be increased. Meanwhile, in order to support both the UCI and the data by the common UL grant signal, the base station  320  may include the t subframe period based on the UL grant transmission/reception time point in the UL grant or notify the terminal  310  of the t subframe period based on SFN #0 by the RRC message in advance. Alternatively, if there is no separate t subframe period information in the UL grant, the terminal  310  may be operated in the t′ subframe period for the data transmission all the times and then may be operated by being reckoned as the t subframe period if the control information transmission is indicated by the UL grant or a higher layer control signal. If the control signal is instructed to be transmitted as the higher layer control signal in a specific period, the uplink resource may be assigned at a k subframe period based on a first UL subframe indicated in the UL grant or the subframe in which the UL grant is transmitted and received.   If DL+UL MCOT is notified by a DL control signal (e.g., common DCI, etc.), the terminal  310  is operated by CAT2 LBT in the case where it is included in the DL+UL MCOT and by CAT4 LBT in the case where it is not included in the DL+UL MCOT. The terminal that has not received the DL+UL MCOT information is operated by a less aggressive CAT4 LBT for coexistence with WiFi.   The terminal  310  may be operated by a CAT2 LBT if it is assigned an UL grant for a short UL burst, for example, one UL subframe, and may be by the CAT4 LBT if it is assigned an UL grant for a long UL burst, for example, two or more UL subframes.       
 
         [0124]    If the terminal  310  is set to try the transmission in two or more UL subframes in the UL burst and is set to try the transmission only in one of the two UL subframes, the terminal  310  may be operated by the CAT2 LBT and if the terminal  310  is set to try the transmission in two or more UL subframes, the terminal  310  may be operated by the CAT4 LBT.
       In the multi subframe scheduling, if the retransmission resource is assigned in advance, the terminal  310  may shorten the delay until it receives the UL grant for the LBT failure again and transmits it.   Describing in detail the conditions of defining the LBT failure, there may be 1) if the LBT fails in all of the N multi subframes indicated in the UL grant of the multi subframe scheduling, and 2) if the LBT fails in all the plurality of UL resources in one carrier in a particular timer, 3) if the LBT fails in all the plurality of UL resources in a plurality of carriers within the particular timer, or the like.   UL subframe for retransmission only: The NDI is not indicated every UL subframe, and the base station  320  may set a location of UL subframe or UL burst for retransmission only by the higher layer control signal such as RRC at a specific time (e.g., offset, period, or the like) and/or a specific CC. In this case, the NDI for identifying the retransmission in the multi subframe UL grant need not be included every subframe. The base station  320  instructs the terminal  310  to transmit the retransmission data at the specific time and/or the specific CC when instructing the retransmission of the UL data that has failed to receive and the terminal  310  may transmit the retransmission packet instead of a new transmission if the information thereon matches each other.   Since PRACH and other UL signals have different transmission timings, other UL signals may lose transmission opportunities due to the PRACH signal during the LBT operation. Therefore, a method for transmitting PRACH immediately after DRS transmission time point without data is possible.   Based on the setting of the base station  320 , the terminal  310  may use an LBT gap shorter than an LBT gap set for transmitting an HARQ initial transmission packet with respect to an HARQ retransmission packet. According to one embodiment, the length of the LBT gap may be set differently in inverse proportion to the number of retransmissions. In this case, the LBT gap may be set to be a length of one CCA slot in the case of the CAT2 LBT and may be set to be a size of the window that generates the backoff value in the case of the CAT4 LBT.   The terminal  310  may be set to use LBT gaps having different lengths depending on the distance from the base station  320  by the setting of the base station  320 . For example, the terminal  310  that is far away from the base station  320  may use a short LBT gap and the terminal  310  that is close to the base station  320  may use a long LBT gap. In this case, the LBT gap may be set to be a length of one CCA slot in the case of the CAT2 LBT and may be set to be a size of the window that generates the backoff value in the case of the CAT4 LBT.   Based on the setting of the base station  320 , the terminal  310  may not transmit but skip one UL resource (e.g., k subframe) due to the LBT failure among a plurality of UL subframes within UL burst assigned by the multi subframe scheduling and then may transmit the UL resource having the reduced size in the subsequent UL resource (k+1 subframe) according to the predetermined rule. Based on the setting of the base station  320 , the first terminal #1 may apply a shorter LBT gap to transmit data delayed due to the LBT failure. At this time, the second terminal #2 assigned to the next subframe (i.e., k+1 subframe) which the first terminal wants to transmit may detect the UL signal from the first terminal #1 by the LBT and transmit data in the remaining UL resources having the reduced size according to the predetermined rule. For this operation, a TB assigned to the terminal  310  in one subframe may be made up of a plurality of partial coding blocks.   If a base station  320  uses a physical layer transmission scheme capable of simultaneously receiving UL signals of a plurality of terminals  310  from the same resource, that is, a non-orthogonal multiple access scheme, it may be combined well with grant-free or SPS transmission schemes that transmit resources without UL grant. The multi subframe scheduling scheme or the SPS-multi subframe scheduling scheme of the present disclosure may also be operated together with the non-orthogonal multiple access scheme. However, if the terminal  310  is operated in the licensed band, instead of the LBT, the terminal  310  may select and transmit one UL resource among a plurality of UL resources in one UL burst or may determine whether to retransmit the subsequent UL resource by receiving UE group common ACK/NACK of the base station  320  directly responding to the UL transmission in the same subframe. The UE group common NACK may be transmitted according to the following conditions in order for the base station  320  to instruct the terminal  310  to perform the retransmission. That is, if the UL signals of all the terminals  310  transmitted from the UL resource of the subframe are input having a predetermined value or greater and thus the reception of the base station  320  fails with respect to a predetermined number or more of terminals  310 , the base station  320  may transmit the UE group common NACK signal. The terminal having the UE group common NACK signal from the base station  320 , the terminal  310  may perform the retransmission in the next UL resource like the operation for the LBT failure. Further, the terminal  310  that has received the UE group common ACK signal or has received nothing from the base station  320  may consider that the transmission in the previous UL resource was successful.       
 
       [Uplink Multi Subframe Scheduling Method] 
       [0133]    In the present disclosure, a multi subframe scheduling method for assigning a plurality of consecutive resources in the uplink is proposed. In this case, unlike the general multi subframe scheduling, according to an embodiment of the present disclosure, the multi subframe scheduling may be repeated at a fixed period in order to support a service characterized by periodic traffic patterns. 
         [0134]    Semi-persistent scheduling (SPS) was supported for fixed period traffic according to the related art. The terminal  310  may receive configuration information to generate a TB to transmit such as an SPS resource period, RB assignment, and MCS as the RRC message from the network to an uplink shared channel (UL-SCH) and may be prepared to transmit the SPS. Further, for the SPS resource and the transmission information based on the SPS setting, the terminal  310  may transmit data if the UL buffer is not empty. On the other hand, if the UL buffer is empty, the terminal  310  may not transmit data in the activated SPS resource except for transmission of a PHR if the uplink SPS skip (SkipUplinkTxSPS) is set. If the UL buffer is empty, the terminal  310  pads the assigned SPS resource, that is, needs to transmit a zero medium access control (MAC) protocol data unit (PDU) if SkipUplinkTxSPS is not set. If the consecutive frequency of transmission of the implicitReleaseAfter counter value set by the RRC and the zero MAC PDU is equal, the terminal  310  may perform a release operation to clear the set an UL SPS resource. The release operation is necessary to prevent waste of the SPS resource. Since the SPS resource is periodically secured, waste occurs if the terminal  310  does not use the SPS resource. In order to minimize the waste, the base station  320  may instruct the terminal  310  to perform activation or release by the PDCCH. In the case of the release, an implicit or explicit method is possible. The case where the terminal  310  receives PDCCH SPS release is different from the case where the SPS setting is released by the RRC message, and the SPS setting still maintained. Therefore, the base station  320  may reactive the SPS setting of the terminal that has been released by the PDCCH SPS activation. According to one embodiment, the terminal  310  determines the SPS release and then transmit an SPS Confirmation MAC command element (CE) to the base station  320  by a first initial transmission packet assigned to check the release. The terminal  310  which transmits the SPS Confirmation MAC CE may delete the assigned SPS resource. 
         [0135]    Meanwhile, the terminal  310  may perform one or a plurality of RRC configurations for the SPS multi subframe (MS) scheduling in one cell/carrier and one setting may include at least one information of a logical channel, a data resource bearer, numerology, and service. The terminal can transmit the UL data to be transmitted in association with at least one of the logical channel, the data resource bearer, the numerology, and the service in the assigned SPS-multi subframe resource based on the setting. The additional setting to be referred to by the terminal  310  in order to select what type of data the terminal  310  transmits in connection with the RRC configuration may be extended and applied to even the case where an additional dynamic UL grant is given together with the SPS-multi subframe, for example, in the case where the retransmission of the resource within the UL burst is assigned to a dynamic UL grant. 
         [0136]      FIG. 6  is a diagram showing an example of SPS assignment according to an embodiment of the present disclosure. 
         [0137]    Referring to  FIG. 6 , the SPS in the case where an SPS period  650  is 10 ms. Further, the following drawing describes, by way of example, the case where the SPS period  650  is 10 ms, but the present embodiment is not limited thereto. Therefore, the SPS period  650  may be shorter or longer than 10 ms. The terminal  310  may apply the activation  610 /release  630  from the earliest SPS resources  620  and  640  after receiving PDCCH SPS activation  610  or SPS release  630  message. The locations of the UL SPS resources  620 ,  625  and  640  are based on the following Equation using a system frame number (SFN), a subframe index, a UL SPS period (semiPersistSchedIntervalUL), and a subframe offset (Subframe_offset) as an input. At this time, the subframe offset is provided in the specification only when two SPS resources are assigned to one frame in the TDD frame structure, and is used to determine the SPS resource location depending on the subframe offset value for each TDD frame structure. 
         [0000]      (10*SFN+subframe)=[(10*SFN start time +subframe start time )+ N *semiPersistSchedIntervalUL+Subframe_Offset*( N  modulo2)] modulo10240 
         [0138]      FIG. 7  is a diagram showing an example of SPS assignment in an unlicensed band according to an embodiment of the present disclosure. 
         [0139]    Referring to  FIG. 7 , the base station  320  may instruct the terminal  310  to perform the general SPS setting and the transmission operation even in the unlicensed band. That is, the terminal  310  may apply activation  710 /release  730  from the earliest SPS resources  720  and  740  after receiving PDCCH SPS activation  710  or SPS release  730  message. However, as illustrated in  FIG. 7 , the terminal  310  performs listen-before-talks (LBTs)  760  and  765  before each transmission in the SPS resources  720 ,  725 , and  740  assigned to the unlicensed band and perform the transmission in the corresponding SPS resources  720  and  725  only when the LBTs  760  and  765  succeed. If the LBTs  760  and  765  fail, the terminal  310  waits until the next SPS resource or performs the retransmission if the base station  320  dynamically grants retransmission resources. This may cause delay problems due to the characteristics of the service using SPS. 
         [0140]    Therefore, according to the present disclosure, when the consecutive SPS resources are further assigned in one SPS period, the terminal  310  tries to support a retry in other UL resources when the LBT fails in one UL resource. 
         [0141]      FIG. 8  is a diagram illustrating an example of SPS assignment according to an embodiment of the present disclosure. 
         [0142]    Referring to  FIG. 8 , the base station  320  may add UL burst length information to the SPS configuration information of the RRC message and transmit the UL burst length information to the terminal  310  by changing the existing SPS setting scheme as small as possible. Further, the terminal  310  may set UL resources to be assigned to the length of the UL burst continued in each SPS period  850  based on the RRC SPS setting. The consecutive UL burst length may be represented by at least one of, for example, a subframe unit, a slot unit, a mini slot unit, a symbol unit, and the like. For example, in the case of  FIG. 8 , the UL burst length may be given by 3. Therefore, resources of three SPS UL subframes  820 ,  821 , and  823  may be assigned. 
         [0143]    Further, the terminal  310  may apply activation/release from the earliest SPS resources  820 ,  821 ,  823 ,  825 , and  840  after receiving PDCCH SPS activation  810  or SPS release  830  message. In this case, if the terminal  310  receives the PDCCH SPS activation  810 , the terminal  310  performs the LBT before the first SPS resource  860  of the UL burst assigned to the unlicensed band, and if the LBT  860  succeeds, may perform the transmission in the corresponding SPS resource  820 . At this time, if the LBT  860  fails, the terminal  310  may try LBTs  861  and  863  in the subframes  821  and  823  corresponding to the consecutive UL burst length, and if the LBTs  861  and  863  succeed, may perform the transmission in the corresponding SPS resources  821  and  823 . Further, if all of the LBTs  860 ,  861 , and  863  in the first UL burst fail, the terminal  310  tries LBTs  865 ,  866 , and  867  in the next SPS resources  825 ,  826 , and  827  to perform the UL data transmission.  FIG. 8  illustrates that the LBT  860  succeeds in the first SPS resource  860  of the first UL burst, and thus the terminal  310  transmits UL data, and the LBT  866  succeeds in the second SPS resource  866  of the second UL burst and thus the terminal  310  transmits UL data. 
         [0144]    Meanwhile, in the first resource  820  of the UL burst, the terminal  310  may fetch data to be transmitted from the determined HARQ process according to the HARQ process ID determination method based on the existing SPS setting. At this time, the HARQ process ID to be used in the SPS resource may be determined according to the following Equation. 
         [0000]      HARQ Process ID=[floor(CURRENT_ TTI /(semiPersistSchedIntervalDL+Subframe_Offset*( N  modulo2)))] modulo numberOfConfSPS-Processes 
         [0000]      CURRENT_ TTI =[(SFN*10)+subframe number] 
         [0145]    Further, unlike the HARQ process ID to be used for the first SPS resource  820  of the UL burst, the HARQ process ID to be used for the other SPS resources  821  and  823  in the UL burst may have different determination methods according to the condition. For example, if the terminal  310  retries an initial transmission packet that is not transmitted due to the LBT  860  failure in the UL burst to the succeeding SPS resources  821  and  823 , the terminal  310  may use the same HARQ process ID as the packet in which the previous LBT fails 1) all the times or 2) in accordance with the setting of the base station  320 . Alternatively, the terminal  310  may use 3) the HARQ process ID that is continued to the HARQ process ID of the packet in which the previous LBT fails and is not used yet, based on the setting of the base station, may use 4) the smallest or largest ID among the HARQ process IDs not yet used depending on the setting of the base station  320 , or may use 5) an ID obtained by the HARQ process ID determination method for the initial transmission. 
         [0146]    According to one embodiment, the terminal  310  needs to transmit the SPS Confirmation MAC CE to the base station  320  after the SPS release. However, if the SPS activation and SPS release operations happen, it may be wasteful for the terminal  310  to use the SPS resource to transmit the SPS Confirmation MAC CE. Alternatively, like streaming, a service whose period is constant but traffic size varies needs to be supported. Alternatively, the UL burst length should be adaptively controlled according to the congestion of the surrounding channels. In order to satisfy the above requirements, a method for dynamically setting, by the base station  320 , SPS resource assignment may be required. The base station signal for the dynamic additional setting may have an identifier or an expression format to be identified from a general dynamic UL grant signal. In addition, if there are a plurality of SPS resource assignments, an additional dynamic UL grant signal may include the identifier for identifying the SPS setting. The terminal  310  may identify whether the UL grant signal is different from the normal UL grant based on the identifier, or identify an additional UL grant for a certain SPS setting. 
         [0147]      FIG. 9  is a diagram illustrating an example of SPS assignment according to an embodiment of the present disclosure. 
         [0148]    Referring to  FIG. 9 , the base station  320  transmits downlink control indicators (DCI)  910  and  915  to the terminal  310  on the PDCCH to instruct the use of the earliest SPS UL bust resources  920 ,  921 ,  923 ,  925 ,  926 , and  927 ). At this time, the base station  320  may identify a DCI format indicating the use of the earliest SPS UL burst resources  920 ,  921 ,  923 ,  925 ,  926 , and  927  or identifies the DCI by a specific field and transmit it to the terminal  310 . According to one embodiment, the time point when the terminal  310  receives the DCIs  910  and  915  and the start time point of the UL bursts  920 ,  921 ,  923 ,  925 ,  926 , and  927  may have an interval of x ms. In this case, if the start time point of the UL burst is not specified in the DCIs  910  and  915 , the initial SPS resources  920  and  925  of the earliest UL SPS bursts  920 ,  921 ,  923 ,  925 ,  926 , and  927  may be assigned first. If the starting time of the UL burst is specified in the DCI, 1) for example, if the terminal  310  receives the DCI specified by x in the k subframe, the terminal  310  is set to be assigned the SPS resources  920 ,  921 ,  923 ,  925 ,  926 , and  927  from the k+x subframe to the SPS resources  920 , or 2) for example, if the terminal  310  receives the DCI specified by y in the k subframe, the earliest UL burst start time point is k+x subframe and the terminal  310  may be set to be assigned the SPS resources  920 ,  921 ,  923 ,  925 ,  926 , and  927  from the k+x+y subframe. 
         [0149]    According to an embodiment, the base station  320  may set the interval between the DCI reception time point  910  and  915  and the first UL SPS resource time points  920  and  925  to be at least 4 ms for the preparation time of the terminal  310  in the case of the SPS activation and then may reduce the interval to 1 or 2 ms before the SPS release. The terminal  310  generates packets to be transmitted in advance after the first SPS bursts  920  and  925  depending on the SPS activation so that the uplink data may be transmitted in the assigned SPS resources  920 ,  921 ,  923 , and  925 ,  926 , and  927  even if the interval is short as 1 or 2 ms. According to an embodiment, the base station  320  may indicate 4 ms for the initial transmission and may indicate 1 or 2 ms for retransmission in which the HARQ process ID and RV are unchanged. 
         [0150]    Meanwhile, the LBTs  960 ,  961 ,  936 ,  965 ,  966 , and  967  have been described with reference to  FIG. 8 , and therefore a detailed description thereof will be omitted. 
         [0151]      FIGS. 10, 11, 12, 13, 14, and 15  are diagrams illustrating examples of SPS consecutive subframe assignment method according to various embodiments of the present disclosure. 
         [0152]    Meanwhile, the base station  320  may assign the plurality of subframes to the terminal  310  by one UL grant. The UL grant may be newly designed to reuse the existing UL grant (for two TB assignments) or to represent any k subframes. 
         [0153]    Referring to  FIG. 10 , the base station  320  may indicate the number of consecutive subframes  1021 ,  1022 ,  1023 ,  1031 ,  1032 ,  1033 ,  1034 ,  1041 , and  1042  constituting UL bursts  1020 ,  1030 , and  1040  by UL grants  1010 ,  1013 , and  1015 . In addition, the base station  320  may indicate various common or separate variables of the UL bursts  1020 ,  1030 , and  1040  and the subframes  1021 ,  1022 ,  1023 ,  1031 ,  1032 ,  1033 ,  1034 ,  1041 , and  1042  to the terminal  310  by the UL grants  1010 ,  1013 , and  1015 . 
         [0154]    The variables used in the UL grants  1010 ,  1013 , and  1015  includes HARQ process related information such as an HARQ process ID, a new data indicator (NDI), and RV and additional information such as a UL transmit power control (UL TPC) command, an SRS transmission command, and LBT information. According to the operation example, some variables are identified into variables common to the UL burst or for each subframe. 
         [0155]    According to the example illustrated in  FIG. 10 , the base station  320  may dynamically indicate the lengths of the UL bursts  1020 ,  1030 , and  1040 , that is, the number of consecutive subframes by 3, 4, and 2 for every UL grant  1010 ,  1013 , and  1015 . However, the locations of the first subframes  1021 ,  1031 , and  1041  to which the UL bursts  1020 ,  1030 , and  1040  are transmitted may be set periodically  1050  (interval of 10 ms in the example of  FIG. 10 ) at a predetermined fixed location. The base station  320  may notify the terminal  310  of the configuration information of the fixed locations of the first subframes  1021 ,  1031  and  1041  of the UL bursts  1020 ,  1030  and  1040  by the RRC message, the PBCH or the MAC CE. Since the locations of the first subframes  1021 ,  1031  and  1041  of the UL bursts  1020 ,  1030  and  1040  are fixed, the locations of the first subframes of the UL bursts  1020 ,  1030  and  1040  from the UL grants  1010 ,  1013  and  1015  may be different from each other as illustrated in  FIG. 10 . 
         [0156]    Meanwhile, since the locations of the first subframes  1021 ,  1031  and  1041  of the UL bursts  1020 ,  1030  and  1040  are fixed, the base station  320  does not explicitly notify the delay time between the separate UL grants  1010 ,  1013 ,  1015  and the UL data and the terminal  310  may be operated to start the transmission at the start location of the earliest UL bursts  1020 ,  1030 , and  1040  at the time point when it receives the UL grants  1010 ,  1013 , and  1015 . Therefore, if the base station  320  wishes to transmit the fast UL grant, the base station  320  may transmit the UL grants  1010 ,  1013 , and  1015  in the previous subframe shorter than 4 ms at the start location of the UL bursts  1020 ,  1030 , and  1040 . For example, the third UL grant  1015  may be transmitted in a subframe 2 ms ahead of the third UL burst  1040 . Meanwhile, if the interval between UL bursts is less than 4 ms, the terminal may additionally transmit an indicator for the base  310  station  320  to identify whether the terminal  310  transmits the UL data at the earliest UL burst location or the second UL burst location. 
         [0157]    Referring to  FIG. 11 , similar to the example of  FIG. 10 , the base station  320  may statically notify the terminal  310  of the lengths of the UL bursts  1120 ,  1130 , and  1140  by the RRC message, the PBCH, or the MAC CE. That is,  FIG. 10  illustrates, by way of example, that the base station  320  dynamically indicates the number of subframes constituting UL burst by UL grant. By the way, referring to  FIG. 11 , the base station  320  statically notifies the terminal  310  of the lengths of the UL bursts  1120 ,  1130  and  1140  by the RRC message, the PBCH, or the MAC CE and the information on the lengths of the UL bursts  1120 ,  1130 , and  1140  may be included in the UL grants  1110 ,  1113  and  1115 .  FIG. 11  illustrates, by way of example, that the lengths of the UL bursts  1120 ,  1130 , and  1140  are 3 ms. 
         [0158]    Referring to  FIG. 12 , the base station  320  may dynamically notify the terminal  310  of the repetition frequency of the UL bursts  1220 ,  1230 , and  1240  by the common or dedicated DCI within the PDCCH by the UL grant  1210 . Further, the base station  320  may statically notify the terminal  310  of the length of the UL bursts  1220 ,  1230  and  1240  by the RRC message, the PBCH, or the MAC CE. According to the embodiment, the base station  320  may statically notify the terminal  310  of the interval between the bursts  1220 ,  1230  and  1240  by the RRC message, the PBCH, or the MAC CE or may dynamically notify the terminal  310  of the interval by an L  1  signal. In the example of  FIG. 12 , the base station  320  may notify the terminal  310  that the repletion number of the UL bursts  1220 ,  1230  and  1240  is three times by the UL grant  1210  message and that the length of the UL bursts  1220 ,  1230  and  1240  is 3 ms by the RRC message, the PBCH, or the MAC CE. 
         [0159]    Referring to  FIG. 13 , the base station  320  may dynamically notify the terminal  310  of the lengths and the repetition frequency of the UL bursts  1320 ,  1330 , and  1340  by the common or dedicated DCI within the PDCCH by the UL grant  1310 . The example has the disadvantage of increasing the size of the UL grant. According to the embodiment, the base station  320  may statically notify the terminal  310  of the interval between the bursts  1320 ,  1330  and  1340  by the RRC message, the PBCH, or the MAC CE or may dynamically notify the terminal  310  of the interval by an L1 signal. In the example of  FIG. 13 , the base station  320  may notify the terminal  310  that the repetition frequency of the UL bursts  1320 ,  1330 , and  1340  are three times and the lengths of the UL bursts  1320 ,  1330  and  1340 , respectively, are 3 ms, 4 ms, 2 ms by the UL grant  1310  message. 
         [0160]    Differently from the example described above with reference to  FIGS. 10 to 13 , referring to  FIG. 14 , the base station  320  may dynamically assign bundles  1460  and  1470  (set of UL bursts) of UL bursts  1420 ,  1425 ,  1427 ,  1430 ,  1435 , and  1437  to the terminal  310  by each UL grant  1410  and  1415 . The interval between the UL bursts in one of UL grant  1410  and  1415  may be explicitly set to be equal to the lengths of the UL bursts  1420 ,  1425 ,  1427 ,  1430 ,  1435 , and  1437 , or may be implicitly determined depending on the type (e.g., data and control signal) of information to be transmitted to the assignment resource. In the case of the data, it is advantageous to continuously assign the UL bursts in the LBT performance and in the case of the control signal, it is advantageous to minimize the control load by the periodic resource assignment. Further, the base station  320  may statically notify the terminal  310  of the length of the UL bursts  1420 ,  1425 ,  1427 ,  1430 ,  1435 , and  1437  by the RRC message, the PBCH, or the MAC CE. In the example of  FIG. 14 , the base station  320  may dynamically inform the terminal  310  that each of the bundles  1460  and  1470  of UL bursts includes three UL bursts  1420 ,  1425 ,  1427 ,  1430 ,  1435 , and  1437  by the UL grants  1410  and  1415  and can statically notify the terminal  310  of the lengths of the UL bursts  1420 ,  1425 ,  1427 ,  1430 ,  1435 , and  1437  by the RRC message, the PBCH, or the MAC CE. 
         [0161]    Referring to  FIG. 15 , like the example of  FIG. 15 , the base station  320  may dynamically assign s UL bursts  1520 ,  1525 ,  1525 ,  1530 ,  1535 , and  1537  to the terminal  310  by the common DCI or the dedicated DCI along with UL grants  1510  and  1515 . In the example of  FIG. 15 , the base station  320  may dynamically notify the terminal  310  that each of the bundles  1560  and  1570  of the UL bursts include three UL bursts  1520 ,  1525 ,  1527 ,  1530 ,  1535 , and  1537  and the lengths of the UL bursts  1520 ,  1525 ,  1527 ,  1530 ,  1535 , and  1537  by the UL grants  1410  and  1415 . 
         [0162]    On the other hand, if the LBT fails for one UL resource, the terminal  310  may retry the next UL resource, but if the validity period of the data packet transmitted from the UL resource depending on the setting of the base station  320  expires, the terminal  310  may transmit a new packet without the retry. The base station  320  may set the valid period in the terminal  310  by the RRC message in consideration of the maximum delay depending on the service/traffic requirements of the terminal  310 . The validity period may be represented by absolute time and subframe/slot/symbol unit, or may be replaced with a certain number of times. The specific number of times may be, for example, the frequency of SPS bursts that has failed or the SPS resource that has failed. 
       Skipping UL Grant Related Operation 
       [0163]    If the UL data is not present in the buffer, for the SPS resource assigned to the terminal  310  set to skip the UL grant, the base station  320  may not identify whether the terminal  310  skips the SPS resource or the LBT fails in the SRS resource if the base station  320  fails to receive the PUSCH to which the terminal  310  is transmitted. Since the base station  320  may not identify the above two situations and therefore may not perform the operation of explicitly transmitting the SPS release, the terminal  310  needs to compare an ImplicitReleaseAfter counter value, which is an implicit method, with a preset maximum value. However, since the terminal  310  does not actually transmit the zero MAC SDU, it does not increase the ImplicitReleaseAfter counter value for the SPS resource in which the LBT fails. On the other hand, since the base station  320  increases the ImplicitReleaseAfter counter value for the SPS resource reception failure, if the increased ImplicitReleaseAfter counter value reaches the preset maximum value, the base station  320  determines that the terminal  310  is in the SPS release. Accordingly, the base station  320  releases the SPS resource set to the terminal  310  but the terminal  310  still understands that the SPS resource is set, such that the terminal  310  transmits an UL to the UL resource that is not assigned. 
         [0164]    In order to address the problem, the terminal  310  transmits a signal for determining an accurate situation to the base station  320  before the base station  320  determines that the terminal  310  is in the SPS release or may transmit a signal for obtaining the SPS activation again after the base station  320  determines that the terminal is in the SPS release. The terminal  310  may transmit 1) information (e.g., SPS Keep Alive MAC CE) requesting to maintain the SPS in the active state to the base station  320  through the PUSCH if there is the UL grant assigned to the PCell or another SCell before the SPS release. At this time, the terminal  310  may transmit the SPS Keep Alive MAC CE together with a carrier indicator field (CIF). Alternatively, 2) the terminal  310  may request the UL grant to the SR or the BSR assigned to the PCell or another SCell and then transmit the information (e.g., SPS Keep Alive MAC CE) requesting to maintain the SPS in the active state to the base station  320  through the PUSCH, for the UL grant assigned before the SPS release. At this time, the terminal  310  may transmit the SPS Keep Alive MAC CE together with the CIF or a small cell group (SCG). Alternatively, 3) the terminal  310  may request the UL grant to the SR or the BSR assigned to the PCell and then transmit an RRC connection request message or an RRC connection re-establishment request message to the base station  320  to the base station  320 , for the UL grant assigned after the SPS release. 
         [0165]    Further, in order to prevent the ImplicitReleaseAfter counter value from rapidly increasing, the base station  320  may perform counting every SPS resource to prevent the ImplicitReleaseAfter counter value from increasing and perform counting once every SPS resource if all the SPS resources of each UL burst fail to increase the ImplicitReleaseAfter counter value. In order to use the method, both the base station  320  and the terminal  310  may be configured to count the ImplicitReleaseAfter counter value in the same manner, or the base station  320  may set the counting method in the terminal  310 . 
         [0166]    The SPS-multi subframe setting proposed in the present disclosure is used to reduce the delay until the message  3  is transmitted to the UL grant of the random access response (RAR) at the time of handover (HO) and the base station  320  may include the SPS assignment in the HO command or PRACH configuration. 
         [0167]      FIG. 16  is a diagram illustrating an example of a multi-subframe setting operation of a base station according to an embodiment of the present disclosure. 
         [0168]    Referring to  FIG. 16 , in operation  1610 , the base station  320  may transmit an RRC configuration message including the configuration information for an SPS MS to the terminal  310 . 
         [0169]    Further, in operation  1620 , the base station  320  may transmit a dynamic SPS MS grant signal to the terminal  310 . This has been described with reference to  FIGS. 6 to 15 , and a detailed description thereof will be omitted. 
         [0170]    The base station  320  may receive the UL resource in the UL burst in operation  1630  and may determine whether the (uplink) packet reception transmitted from the terminal  310  through the UL resource succeeds in operation  1640 . 
         [0171]    If the packet reception succeeds, the base station  320  may transmit HARQ feedback (ACK) to the terminal  310  in operation  1645 . Further, in operation  1630 , the base station  320  may try to receive uplink data of the terminal  310  from another UL resource in the UL burst. 
         [0172]    On the other hand, if the packet reception fails, the base station  320  may increase the ImplicitReleaseAfter counter value in operation  1650 . Further, in operation  1660 , the base station  320  may determine whether the ImplicitReleaseAfter counter value has reached the preset maximum value. If the ImplicitReleaseAfter counter value does not reach the preset maximum value, in operation  1630 , the base station  320  may try to receive uplink data of the terminal  310  from another UL resource in the UL burst. 
         [0173]    On the other hand, if the ImplicitReleaseAfter counter value reaches the predetermined maximum value, in operation  1670 , the base station  320  may determine whether the keep alive signal (SPS Keep Alive MAC CE) transmitted from the terminal  310  is received. That is, the base station  320  may determine whether the information requesting to maintain the SPS in the active state is received from the terminal  310 . 
         [0174]    If the base station  320  receives the keep alive signal, the base station  320  initializes the ImplicitReleaseAfter counter value in operation  1675 , and may proceed to operation  1630 . 
         [0175]    If the ImplicitReleaseAfter counter value reaches the preset maximum value, the base station  320  determines that the terminal  310  is in the SPS release. However, as in the above case, the terminal  310  does not increase the ImplicitReleaseAfter counter value for the SPS resource in which the LBT fails. In this case, the base station  320  releases the SPS resource set in the terminal  310 , and the terminal  310  determines that the SPS resource is still set and thus may transmit the keep alive signal to the base station  320  to prevent the UL transmission to the UL resource that is not assigned. If the terminal  310  transmits the keep alive signal to the base station  320 , the base station  320  is maintained in the SPS active state and may try to receive the UL data from the terminal  310  even if the ImplicitReleaseAfter counter value reaches the predetermined maximum value. 
         [0176]    Further, if the base station  320  does not receive the keep alive signal in operation  1670 , the base station  320  may terminate the SPS MS resource in operation  1680 . 
         [0177]    The keep alive signal may be replaced with another type of UL signal of the terminal  310 , for example, SR, BSR, SRS, MAC CE, or the like. At this time, in order to be identified from the existing UL signal, at least one of a new bit, a field, and a sequence is added to transmit the assigned information for the keep alive signal or reuse the existing UL signal but may consider the UL signal as the keep alive signal as long as the base station  320  and the terminal  310  satisfy a specific condition. For example, if the terminal  310  transmits the UL signal before the ImplicitReleaseAfter counter value reaches the maximum value (i.e., preset maximum value) after the timer set after the last transmission in the SPS UL burst expires, the base station  320  receiving the UL signal may regard the UL signal as the keep alive signal. As another example, after the ImplicitReleaseAfter counter value reaches a first threshold value, if the terminal  310  transmits the UL signal before the ImplicitReleaseAfter counter value reaches a second threshold value, the base station  320  receiving the UL signal may regard the UL signal as the keep alive signal. 
         [0178]    Further, in operation  1690 , the base station  320  may determine whether the RRC connection reestablishment message is received. If the base station  320  receives the RRC connection reestablishment message, the base station  320  returns to operation  1610 , and if not, the base station  320  may terminate the procedure. 
         [0179]      FIG. 17  is a diagram illustrating an example of a multi-subframe setting operation of a terminal according to an embodiment of the present disclosure. 
         [0180]    Referring to  FIG. 17 , in operation  1710 , the terminal  310  may receive the RRC configuration message including the configuration information for the SPS MS from the base station  320 . 
         [0181]    Further, in operation  1720 , the terminal  310  may receive the dynamic SPS MS grant signal from the base station  320 . This has been described with reference to  FIGS. 6 to 15 , and a detailed description thereof will be omitted. 
         [0182]    Hereinafter, in operation  1730 , the terminal  310  may determine whether there is data to be transmitted in the UL buffer of the terminal  310  at the UL resource time point assigned to the terminal  310  in operation  1730 . 
         [0183]    If there is no data to be transmitted in the UL buffer of the terminal  310 , the terminal  310  may increase the ImplicitReleaseAfter counter value in operation  1760 . 
         [0184]    On the other hand, if there is no data to be transmitted in the UL buffer of the terminal  310 , the terminal  310  may perform the LBT on the UL resource in the UL burst in operation  1740 . Further, in operation  1750 , the terminal  310  may determine whether the LBT succeeds. 
         [0185]    If the LBT succeeds, the terminal  310  may transmit the UL data (UL packet) from the UL resource corresponding to the succeeding LBT in the UL burst to the base station  320  in operation  1755 . 
         [0186]    On the other hand, if the LBT fails, in operation  1770 , the terminal  310  may determine in operation  1770  whether the LBT fails for all the UL resources in the UL burst. 
         [0187]    If the LBT does not fail for all the UL resources in the UL burst, the terminal  310  returns to operation  1740  and may perform the LBT on the next UL resource in the UL burst. At this time, the terminal  310  may transmit the keep alive signal (SPS Keep Alive MAC) for requesting the base station  320  to maintain the SPS active state to the base station  320  in operation  1775 . Further, in operation  1740 , the terminal  310  may perform the LBT on the next UL resource in the UL burst if the LBT fails for all UL resources in the UL burst. 
         [0188]    If the LBT fails for all the UL resources in the UL burst, the terminal  310  may increase the ImplicitReleaseAfter counter value in operation  1760 . 
         [0189]    After increasing the ImplicitReleaseAfter counter value in operation  1760 , the terminal  310  may determine whether the ImplicitReleaseAfter counter value reaches the preset maximum value in operation  1780 . If the ImplicitReleaseAfter counter value reaches the preset maximum value, the terminal  310  may release the SPS MS resource in operation  1790 . On the other hand, if the ImplicitReleaseAfter counter value does not reach the preset maximum value, the terminal  310  may wait to receive the dynamic SPS MS grant signal from the base station  320  in operation  1720 . 
         [0190]    Meanwhile, in the example of the consecutive subframe (multi subframe) and UL burst assignment, the location where the terminal  310  performs the LBT may be set by a method of combining (union of CCA gap locations) at least one of the followings. 
         [0191]    a) Perform the LBT in the CCA gap configured for transmission in the first UL subframe assigned to the UL grant. 
         [0192]    b) Perform the LBT in the CCA gap configured for the transmission in the UL burst start subframe. 
         [0193]    c) Perform the LBT in the CCA gap configured for the transmission every UL subframe assigned to the UL grant. 
         [0194]    d) Perform the LBT in the CCA gap configured for the transmission in the corresponding subframe if the terminal  310  sets the CCA gap location (e.g., offset, period, or the like) is set by the separate common DCI and thus the UL burst is located at the location. 
         [0195]    e) Perform the LBT in the CCA gap configured for the transmission in the corresponding subframe if the terminal  310  sets the CCA gap location (e.g., offset, period, or the like) by the higher layer control signal like to the RRC message and thus the UL burst is located at the location. 
         [0196]    Meanwhile, if the base station  320  dynamically notifies the terminal  310  of the CCA gap location by the PDCCH, the base station  320  is based on the subframe for transmitting the UL grant or if the base station  320  statically notifies the terminal  310  of the CCA gap location by the RAC message, the base station  320  may be based on the reference time of the Pcell or the reference time of the DL burst. 
         [0197]    Meanwhile, for the CCA gap setting, a method for setting LBT types (e.g., FBE-CAT2 LBT, LBE-CAT4 LBT, or the like) may be operated according to at least of the following methods. 
         [0198]    a) The terminal  310  uses LBE-CAT4 LBT for transmission in the UL burst start subframe. 
         [0199]    b) The terminal  310  uses FBE-CAT2 LBT for transmission in the UL burst start subframe. 
         [0200]    c) The terminal  310  uses FBE-CAT2 LBT for transmission in the subframe in the bundle of UL bursts. 
         [0201]    d) The terminal  310  uses the FBE-CAT2 LBT in the CCA gap indicated by the common DCI. 
         [0202]    e) The terminal  310  uses the FBE-CAT2 LBT except the final gap of the CCA gaps indicated by the common DCI and uses the LBE-CAT4 LBT in the final gap. 
         [0203]    f) The terminal  310  uses the LBE-CAT4 LBT in the CCA gap indicated by the RRC. 
         [0204]    g) The terminal  310  uses the LBE-CAT4 LBT if the resource is not assigned by the UL grant in the CCA gap indicated by the RRC. 
         [0205]    h) The terminal  310  uses the FBE-CAT2 LBT if the resource is not assigned by the UL grant in the CCA gap indicated by the RRC. 
         [0206]    i) The terminal  310  uses the FBE-CAT2 LBT if the resource is not assigned by the UL grant in the CCA gap indicated by the RRC and is in the UL burst. 
         [0207]    j) When the terminal  310  receives the MCOT (DL+UL) length information by the PDCCH common DCI, if the UL signal within the MCOT is transmitted, the terminal  310  uses the FBE-CAT2 LBT and if the UL signal outside the MCOT is transmitted, the terminal  310  uses the LBE-CAT4 LBT. 
         [0208]    k) When the terminal  310  receives the offset information up to the final subframe of the MCOT by the PDCCH common DCI, if the UL signal within the MCOT is transmitted, the terminal  310  uses the FBE-CAT2 LBT and if the UL signal outside the MCOT is transmitted, the terminal  310  uses the LBE-CAT4 LBT. 
         [0209]    In the multi-subframe scheduling, if the UL grant is duplicated in one terminal  310 , at least one of the following overwriting rules may be applied. 
         [0210]    A new UL grant may remove the existing UL grant except in the following cases: (New UL grant remove all existing UL grant except); 
         [0211]    1) Very next UL grant following DL burst 
         [0212]    2) Existing UL grant within MCOT of eNB w. r. t previous UL grant 
         [0213]    3) Existing UL grant within MCOT of eNB w. r. t new UL grant 
         [0214]    4) Existing UL grant within N subframes of eNB (DL) indicated by eNB 
         [0215]    5) Existing UL grant within N subframes of terminal (UL) indicated by eNB 
         [0216]    According to one embodiment, the base station  320  may update the common DCI notifying the terminal  310  of the end of the MCOT and notify the terminal  310  of the updated common DCI. The base station may not receive 1) the transmission of all terminals  310  in the scheduled UL subframe, or 2) may further extend the end of the MCOT and notify it to the terminal if all terminals receive the LBT failure by the LBT result report. The terminal within the extended MCOT, the terminal may retransmit the UL data transmissions that have failed in the LBT according to a predetermined rule. 
       Multi Subframe Scheduling Method for Notifying LBT Result 
       [0217]    It is difficult for the base station  320  to determine the UL LBT result of the terminal  310  without any report. The base station  320  should determine the reliability of the received PUSCH signal as the detection result of the DMRS multiplexed with the PUSCH and transmitted by the terminal  310 . However, it is difficult for the base station  320  to determine whether the DMRS is not received due to high interference or whether the terminal  310  does not transmit the DMRS due to the LBT failure. Therefore, if the terminal  310  reports to the base station  320  whether the LBT succeeds or fails, the base station  320  may take the operation utilizing the LBT success/failure. As described above, the base station  320  may indicate the fast UL grant to the terminal  310  in which the LBT fails. To support the operation, the format and procedure for reporting the LBT results need to be defined as follows. The signal of the LBT result report may be referred to by various names such as an LBT result report, an LBT result indication, and a DTX indication. 
         [0218]    a) LBT Result Report Format
       For one SCell (or component carrier (CC)): The terminal  310  uses at least one of the format 0, format 1a, and format 1b (FDD 1CC) including the SR among the existing UCI formats not to transmit 1 bit information notifying the LBT result instead of the SR to the base station SR through the unlicensed SCell. Alternatively, according to the existing method, a method for transmitting UCI information (CQI, RI, HARQ-ACK/NACK, NDI) to a PUSCH by multiplexing the UCI with a UL shared channel (UL-SCH) is reused, and thus the LBT result indication may be transmitted using the HARQ-ACK/NACK, other cyclic time shift values, and a spread code in a 1-bit resource that transmits the HARQ-ACK/NACK. Since the unlicensed band operates with the CA, it is sufficient to transmit the actual SR to the PCell (or licensed band S Cell). i) The base station  320  may consider the SR received in the SCell of a particular unlicensed band as the LBT result in that SCell. Alternatively, ii) the base station  320  may regard it as the LBT result for the UL data transmission assigned at the most recent time point. Alternatively, iii) when the base station  320  may not identify the band format, if the SR is received in a manner specified in the following LBT result report procedure, the base station  320  may be operated by considering it as the LBT result. Alternatively, the method of notifying, by a terminal  310 , HARQ DTX to a base station  320  may be applied to the LBT result indication method as it is.   For plurality of SCells or CCs: The terminal  310  uses the format 3 including the SR among the existing UCI formats to transmit 11 bits (FDD)/21 bits (TDD) information for five ccs notifying the LBT result instead of the SR to the base station  320  through the unlicensed SCell. Alternatively, according to the existing method, a method for transmitting UCI information (CQI, RI, HARQ-ACK/NACK, NDI, or the like) by multiplexing the UCI with the UL-SCH is reused, and thus the LBT result indication for two ccs may be transmitted using the HARQ-ACK/NACK, other cyclic time shift values, and a spread code in a 2-bit resource that transmits the HARQ-ACK/NACK. If the number of UCI cell groups set in the terminal  310  is equal to or smaller than 5 or 2 at which the number of CCs that may report the LBT result may be represented at one time, they are mapped in order from the lowest SCell index to identify the LBT result for the specific SCell. If the UCI cell group number is equal to or greater than the 5 or 2, it may be additionally identified according to the time point at which the UCI information is transmitted. For example, the UCI cell group number may be identified as when the UCI information is transmitted in odd subframes, it indicates a 1-5 SCell index, and if the UCI information is transmitted in even subframes, it indicates a 6-10 SCell index.   Meanwhile, if the report information of the LBT result is insufficient for only 1 bit, the subframe index, the report may be made in at least one of the four schemes of the bitmap in the UL burst, the HARQ process ID tried to perform the transmission in the subframe in which the LBT fails to transmit in the failed subframe, and the interval between the subframe in which the LBT fails.       
 
         [0222]    b) LBT Result Report Procedure
       If the terminal  310  intends to transmit the LBT result report to the base station  320 , the method for reporting the LBT result to the PCell or the licensed band SCell may be considered first, but there may be a burden to assign a lot of UCI resources to a rare licensed band. Therefore, according to the present disclosure, the LBT result may be reported in the unlicensed band SCell.   The basic LBT result report procedure is relatively simple under the assumption of the UL grants for one UL subframe. That is, the terminal  310  may transmit the LBT result for the previous UL data to the base station  320  by multiplexing the LBT result with the UL-SCH if the UL data is transmitted in the next assigned resource. However, the method is not easy to identify the case in which the LBT fails consecutively and notify it. If necessary, the method for reusing an SR field for five ccs of UCI format 3 and reporting LBT results for the previous 5 subframes may be addressed. However, the procedure has a disadvantage in that a long delay time is required until a new UL grant and LBT therefor succeed to allow the base station  320  to confirm the LBT results.   If the base station  320  assigns the UL resource to the terminal  310  by the UL grants for the plurality of UL subframes, it is possible to reduce the delay of the LBT result report compared to the case where a UL grant for a single UL subframe is used. This is because the base station  320  assigns the UL subframe having an appropriate number at a time based on the interference of the unlicensed band or the LBT success rate. For example, if four subframes are assigned by one UL grant, the terminal  310  may fail to perform the LBT in a first or second subframe and may successfully perform the LBT in third/fourth subframes. The terminal  310  transmits i) the LBT result report to the base station  320  in the succeeding first subframe (third subframe in the example) to the base station  320  or ii) the LBT result report to the base station  320  in all the succeeding subframes (third and fourth subframes in the above example), among the k assigned subframes.   Various examples that may be generated when assigning three subframes in n subframes and when operated according to i) are described below. If the base station  320  receives the LBT result report from the terminal  310 , the base station  320  may instruct the terminal  310  to retransmit the subframe from [the reception failure subframe just next to the reception success subframe] to the [subframe-1 in which the LBT result report is received]. At this time, the base station  320  may transmit a normal UL grant or the fast UL grant proposed in the present disclosure to the terminal  310  to instruct the retransmission. This may be the following Table 1.       
 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                 Location of 
               
               
                   
                   
                 subframe 
               
               
                   
                   
                 of data to be 
               
               
                   
                 LBT result 
                 retransmitted 
               
               
                   
                 report 
                 due to 
               
               
                 Case 
                 subframe 
                 LBT failure 
               
               
                   
               
             
             
               
                 Success (n + 4), Success (n + 5), Success 
                 n + 4 
                 Absence 
               
               
                 (n + 6) 
               
               
                 Failure (n + 4), Success (n + 5), Success 
                 n + 5 
                 n + 4 
               
               
                 (n + 6) 
               
               
                 Failure (n + 4), Failure (n + 5), Success (n + 6) 
                 n + 6 
                 n + [4, 5] 
               
               
                 Failure (n + 4), Failure (n + 5), Failure (n + 6) 
                 Absence 
                 n + [4, 5, 6] 
               
               
                 Success (n + 4), Failure (n + 5), Failure (n + 6) 
                 Absence 
                 n + [5, 6] 
               
               
                 Success (n + 4), Success (n + 5), Failure 
                 Absence 
                 n + 6 
               
               
                 (n + 6) 
               
               
                 Success (n + 4), Failure (n + 5), Success 
                 n + 6 
                 n + 5 
               
               
                 (n + 6) 
               
               
                   
               
             
          
         
       
       
         
           
             Various examples that may be generated when assigning three subframes in n subframes and when operated according to ii) are described below. If the base station  320  receives the LBT result report from the terminal  310 , the base station  320  may instruct the terminal  310  to retransmit the subframe from [reception failure subframe just next to the subframe receiving the LBT success report] to the [subframe in which the LBT failure report is received—1]. At this time, the base station  320  may transmit a normal UL grant or the fast UL grant proposed in the present disclosure to the terminal  310  to instruct the retransmission. This may be the following Table 2. 
           
         
       
     
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                   
                   
                   
                 Location of 
               
               
                   
                   
                   
                 subframe of 
               
               
                   
                   
                   
                 data to be 
               
               
                   
                 LBT success 
                 LBT failure 
                 retransmitted 
               
               
                   
                 report 
                 report 
                 due to LBT 
               
               
                 Case 
                 subframe 
                 subframe 
                 failure 
               
               
                   
               
             
             
               
                 Success (n + 4), Success (n + 5), Success 
                 n + [4, 5, 6] 
                 Absence 
                 Absence 
               
               
                 (n + 6) 
               
               
                 Failure (n + 4), Success (n + 5), Success 
                 n + 6 
                 n + 5 
                 n + 4 
               
               
                 (n + 6) 
               
               
                 Failure (n + 4), Failure (n + 5), Success 
                 Absence 
                 n + 6 
                 n + [4, 5] 
               
               
                 (n + 6) 
               
               
                 Failure (n + 4), Failure (n + 5), Failure 
                 Absence 
                 Absence 
                 n + [4, 5, 6] 
               
               
                 (n + 6) 
               
               
                 Success (n + 4), Failure (n + 5), Failure 
                 n + 4 
                 Absence 
                 n + [5, 6] 
               
               
                 (n + 6) 
               
               
                 Success (n + 4), Success (n + 5), Failure 
                 n + [4, 5] 
                 Absence 
                 n + 6 
               
               
                 (n + 6) 
               
               
                 Success (n + 4), Failure (n + 5), Success 
                 n + 4 
                 n + 6 
                 n + 5 
               
               
                 (n + 6) 
               
               
                   
               
             
          
         
       
     
         [0228]      FIG. 18  is a diagram illustrating an example of UL multi subframe assignment and a transmission thereof according to an embodiment of the present disclosure,  FIG. 19  is a diagram illustrating an example of a UL multi subframe assignment and a transmission and a retransmission thereof according to an embodiment of the present disclosure, and  FIG. 20  is a diagram illustrating an example of a UL multi subframe assignment and a transmission and a retransmission thereof according to an embodiment of the present disclosure. 
         [0229]    By using the LBT result report described with reference to  FIGS. 18 to 20 , any advantages in the retransmission delay will be described. 
         [0230]    Referring first to  FIG. 18 , the terminal  310  may receive the UL grant of the base station  320  and may successfully transmit HARQ process #0  1811  under the situation in which three consecutive multi-sub-frames (HARQ processes #0, #1, #2)  1811 ,  1813  and  1815  are assigned at an interval of 4 ms at reference numeral  1810 . Further, the terminal  310  receives the UL grant for the multi-subframe starting from subframe n+8 from the base station  320  in the next multi-subframe n+4 at reference numeral  1820  and may prepare the initial transmission packet to be transmitted in the subframe n+8 at reference numeral  1825 . Thus, the terminal  310  may perform initial transmission in the multi-subframe starting from the subframe n+8 at reference numeral  1830 . 
         [0231]    Referring to  FIG. 19 , among HARQ processes #0, #1, and #2 transmission resources  1911 ,  1913 , and  1915  that are assigned from the base station  320  to the terminal  310  by the first multi-frame UL grant, the LBT before the data transmission for subframe n  1911  and subframe n+1  1913 , that is, HARQ process #0  1911  and HARQ process #1  1913  may fail. Accordingly, the terminal  310  may fail to perform the initial transmission in the subframe n at reference numeral  1910 . By the way, the base station  320  may not know whether the failure cause of the reception of the UL PUSCH in the subframe n  1911  and the subframe n+1  1913  is the high interference or the failure of the LBT by the terminal  310 . Accordingly, the base station  320  may complementarily instruct the terminal  310  to perform the assignment for the retransmission in subframe n+4 (e.g., to PCell) at reference numeral  1920 . The terminal  310  may prepare the UL data to be retransmitted in the subframe n+8 according to the instruction at reference numeral  1925  and transmit the retransmission packet in the subframe n+8 at reference numeral  1930 . Therefore, a delay of 8 ms may be required up to retransmit the UL data in which the LBT fails in subframe n in subframe n+8. 
         [0232]    Referring to  FIG. 20 , among HARQ processes #0, #1, and #2, subframes  2011 ,  2013 , and  2015  that are assigned from the base station  320  to the terminal  310  by the first multi-frame UL grant, the LBT before the data transmission for subframe n  2011  and subframe n+1  2013 , that is, HARQ process #0 and HARQ process #1 may fail. Accordingly, the terminal  310  may fail to perform the initial transmission in the subframe n and store the packet whose transmission fails in the buffer ( 2010 ). At this time, the base station  320  may not know in subframe n  2011  and subframe n+1  2013  whether the failure cause of the reception of the UL PUSCH in the subframe n  2011  and the subframe n+1  2013  is the high interference or the failure of the LBT by the terminal  310 . However, if the terminal  310  succeeds to perform the LBT in the subframe n+2  2015  and transmits the LBT result report to the base station  320  at reference numeral  2020  and the base station  320  receives the LBT result report at reference numeral  2025 , the base station  320  may transmit the fast UL grant command for the UL data that is not be transmitted due to the LBT failure in the subframe n+3 to the terminal  310  at reference numeral  2030 . If the terminal  310  receives the fast grant command in the subframe n+3 at reference numeral  2035 , the stored UL data to be transmitted depending on the LBT failure may be transmitted in the immediately next subframe n+4 at reference numeral  2040 . Therefore, it is possible to improve the delay time by 4 ms from the existing 8 ms for the retransmission of the packet in which the LBT fails. Further, the base station  320  transmits the UL grant for the initial transmission of the multi-subframe starting from the subframe n+8 to the terminal  310  in the subframe n+4 at reference numeral  2050 . Accordingly, the terminal  310  may perform the initial transmission in a multi-subframe starting from subframe n+8 at reference numeral  2060 . 
         [0233]    The base station  320  may instruct the fast UL grant to the terminal  310  by the CC scheduling in the PCell or the licensed band SCell or by the self-carrier scheduling in the unlicensed band SCell. 
       Details of PRACH Configuration Method 
       [0234]    The base station  320  may instruct the terminal  310  to perform a random access (RA) access procedure in the unlicensed band SCell. According to the general RA procedure, the base station  320  and the terminal  310  may perform and complete a contention-based RA procedure through the following procedure. 
         [0235]    Previous procedure: The terminal  310  confirms variables (e.g., RAR window, CR timer, backoff index, maximum retry count, variables for power control, etc.) that are related to the location of the RACH resource for RA and the terminal operation required for the RACH procedure through the process of synchronization and SI acquisition. 
         [0236]    Operation 1: The terminal  310  may transmit a random access preamble (RAP) sequence (msg1) to the base station  320 . It is possible to select the preamble ID of one of the selected preamble ID sets. 
         [0237]    Operation 2: The base station  320  may transmit a RAR message (msg2) to the terminal  310 . The terminal  310  may receive the msg2 identified based on the RA-RNTI determined in operation 1. 
         [0238]    Operation 3: The terminal  310  may transmit a specific message (msg3) to the base station  320  by the resource assigned in the msg2. The base station  320  may identify the msg3 of the terminal by the temporary C-RNTI transmitted to the terminal  310  in operation 2. 
         [0239]    Operation 4: The base station  320  may transmit a specific message (message  4 ) to the terminal  310 . The terminal  310  may receive the msg4 identified based on the temporary C-RNTI received in operation 2. 
         [0240]    The terminal  310  may receive the SI block 2 (SIB2) to determine the initial transmit power of the terminal, and may perform the RAP transmission of operation 1 with a predetermined initial transmit power. If the terminal  310  does not receive the RAP message from the base station  320  within a specific period (RAR window) after the terminal  310  transmits the RAP, the terminal  310  determines that the RA fails and the terminal  310  retransmits the RAP message. Generally, the terminal  310  may retransmit the RAP message to the base station  320  as many as the set maximum retry number. If the terminal  310  does not receive the RAR message even after retransmission of the RAP message by the maximum retry number, the terminal  310  increases the transmit power by the power ramping up value set to the transmit power and may start the RA procedure again by resetting the retry number to 0. In the above description, the variables such as the initial transmit power, the RAR window, and the maximum retry number are included in the SIB message of the base station. 
         [0241]    In the case of the contention-free RA procedure, the base station  320  starts the RA of the specific terminal  310  by a physical DL control channel (PDCCH) order or the RRC message of the higher layer. At this time, the signal for each instruction includes a mask index as to which resource of the preamble ID to be used by the terminal  310  and the RACH resource is to be allowed to use. 
         [0242]    The terminal  310  may perform the RAP transmission based on the location of the PRACH resource acquired through the RRC message for SIB2 or mobility/SCell addition with respect to the existing licensed band, the timing notified by the PDCCH order, and the mask index notifying where the PRACH resource is transmitted. Meanwhile, the terminal  310  needs to assign a redundant resource that may perform the RAP try several times to overcome the LBT failure in the unlicensed band. The location of the PRACH resource may notify a PRACH configuration (setting) index set in frame units by including the PRACH configuration index in the PDCCH order or RRC message. The PRACH configuration and its reference time may be defined as shown in the following example by a semi-static or dynamic method. The terminal  310  may determine to which subframe and/or which frequency resource block the RACH resource is assigned depending on the PRACH configuration index. 
         [0243]    a-1) The terminal  310  may apply the FDD/TDD configuration for the licensed band in the same manner even in the unlicensed band SCell on the basis of the PCell subframe index, or a-2) the terminal  310  may additionally receive the FDD/TDD configuration having the different licensed band but the same format and apply the FDD/TDD configuration in the same manner even in the unlicensed band SCell on the basis of the PCell subframe index, or a-3) the terminal  310  may additionally receive the PRACH configuration for the unlicensed band only and apply the PRACH configuration in the same manner even in the unlicensed band SCell on the basis of the PCell subframe index. 
         [0244]    Alternatively, b-1) the terminal  310  may apply the FDD/TDD configuration for the licensed band on the basis of the first DL subframe index acquired by the base station  320  in the SCell, or b-2) the terminal  310  may additionally receive the FDD/TDD configuration having the licensed band but the same format and apply the FDD/TDD configuration on the basis of the first DL subframe index acquired by the base station  320  in the SCell, or b-3) the terminal  310  additionally receive the PRACH configuration for the unlicensed band only and apply the PRACH configuration on the basis of the first DL subframe index acquired by the base station  320  in the SCell. 
         [0245]    Alternatively, c-1) the terminal  310  may apply the FDD/TDD configuration for the licensed band on the basis of the first UL subframe after the final DL subframe index acquired by the base station  320  in the SCell, or c-2) the terminal  310  may additionally receive the FDD/TDD configuration having the licensed band but the same format and apply the FDD/TDD configuration on the basis of the first UL subframe after the final DL subframe index acquired by the base station  320  in the SCell, or c-3) the terminal  310  additionally receive the PRACH configuration for the unlicensed band only and apply the PRACH configuration on the basis of the first UL subframe after the final DL subframe index acquired by the base station  320  in the SCell. 
         [0246]    Alternatively, d-1) the terminal  310  may apply the FDD/TDD configuration for the licensed band in the same manner even in the unlicensed band SCell on the basis of the first PRACH subframe intended by the PDDCH order, d-2) the terminal  310  may additionally receive the FDD/TDD configuration having the different licensed band but the same format and apply the FDD/TDD configuration in the same manner even in the unlicensed band SCell on the basis of the first PRACH subframe intended by the PDDCH order, or a-3) the terminal  310  may additionally receive the PRACH configuration for the unlicensed band only and apply the PRACH configuration in the same manner even in the unlicensed band SCell on the basis of the first PRACH subframe intended by the PDDCH order. 
         [0247]    Alternatively, e-1) the terminal  310  may apply the FDD/TDD configuration for the licensed band in the same manner even in the unlicensed band SCell on the basis of the first UL LBT subframe indicated by the common DCI, e-2) the terminal  310  may additionally receive the FDD/TDD configuration having the different licensed band but the same format and apply the FDD/TDD configuration in the same manner even in the unlicensed band SCell on the basis of the first UL LBT subframe indicated by the common DCI, or e-3) the terminal  310  may additionally receive the PRACH configuration for the unlicensed band only and apply the PRACH configuration in the same manner even in the unlicensed band SCell on the basis of the first UL LBT subframe indicated by the common DCI. 
         [0248]    Alternatively, f-1) the terminal  310  may apply the FDD/TDD configuration for the licensed band in the same manner even in the unlicensed band SCell on the basis of the final UL LBT subframe within the MCOT indicated by the common DCI, f-2) the terminal  310  may additionally receive the FDD/TDD configuration having the different licensed band but the same format and apply the FDD/TDD configuration in the same manner even in the unlicensed band SCell on the basis of the final UL LBT subframe within the MCOT indicated by the common DCI, or f-3) the terminal  310  may additionally receive the PRACH configuration for the unlicensed band only and apply the PRACH configuration in the same manner even in the unlicensed band SCell on the basis of the final UL LBT subframe within the MCOT indicated by the common DCI. 
         [0249]    Alternatively, g-1) the terminal  310  may apply the FDD/TDD configuration for the licensed band in the same manner even in the unlicensed band SCell on the basis of the final subframe within the MCOT indicated by the common DCI, g-2) the terminal  310  may additionally receive the FDD/TDD configuration having the different licensed band but the same format and apply the FDD/TDD configuration in the same manner even in the unlicensed band SCell on the basis of the final subframe within the MCOT indicated by the common DCI, or g-3) the terminal  310  may additionally receive the PRACH configuration for the unlicensed band only and apply the PRACH configuration in the same manner even in the unlicensed band SCell on the basis of the final subframe within the MCOT indicated by the common DCI. 
         [0250]    Among the above-mentioned embodiments, the PRACH configuration for the unlicensed band may be at least one of the following options. i) Get the PRACH configuration for PCell, which is the licensed band, but ignore the configuration for the subframe. ii) Set N consecutive subframes as the PRACH subframe. iii) Set N consecutive subframes having m intervals notified by the PDCCH order as the PRACH subframe. iv) Set as all UL subframes indicated by the UL grant of the multi-subframe scheduling. iv) Set as a first subframe of all UL subframes indicated by the UL grant of the multi-subframe scheduling. iv) Set as a final subframe of all UL subframes indicated by the UL grant of the multi-subframe scheduling. vii) Identify and set the PRACH subframe among the N subframes by bitmap information included in the PDCCH order. viii) Set according to an instruction for one of the PRACH subframe information continuously or periodically composed of bitmap indicated by the SIB2 or the RRC message.
       The terminal  310  receives the DRS based on the DRS configuration in the activated SCell and may consider the next subframe as the UL subframe as long as the PDCCH is not received. Further, the location of the PRACH resource intended by the PDCCH order is at that of the confirmed UL subframe or is not ahead of at least 6 subframes and if the terminal  310  is not assigned the DL or UL resource and may transmit the RAP in the UL subframe before the RAR timer has not expired.       
 
         [0252]    RAR timer alignment: The base station  320  and the terminal  310  should have the same perception of the RAR timer. If the base station  320  instructs the terminal  310  to instruct the RAP transmission for the plurality of unlicensed band SCells by the PDCCH order, a plurality of RAR timers are operated. To address the problem, the following method is possible. 
         [0253]    a) When the RAR timer is operated by one PDCCH order, if the RAP transmission is instructed by the new PDCCH order, the terminal  310  terminates the previous RAR timer and operates a new RAR timer. 
         [0254]    b) When the RAR timer is operated by one PDCCH order, even if the RAP transmission is instructed by the new PDCCH order, the terminal  310  keeps and operates the previous RAR timer. 
         [0255]    c) When the RAR timer is operated by one PDCCH order, if the RAP transmission is instructed by the new PDCCH order, the terminal  310  adds the new RAR timer value to the residual value of the previous RAR timer and is operated. 
         [0256]    d) When the RAR timer is operated by one PDCCH order, if the RAP transmission is instructed by the new PDCCH order, the terminal  310  calculates the area corresponding to the union of the section indicated by the residual value of the previous RAR timer and the section indicated by the new RAR timer value and updates the RAR timer value to the value and is operated. 
         [0257]    e) When the RAR timer is operating by one PDCCH order, if the RAP transmission is indicated by a new PDCCH order, the timer  310  is extended up to the first PRACH subframe indicated by the new PDCCH order and the new RAR timer is operated from the PRACH subframe. This is the same as operating the RAR timer updated immediately in the subframe receiving the PDCCH order by adding the remaining time up to the first PRACH subframe indicated by the new PDCCH order to the new RAR timer value. 
         [0258]    Operation related to a delay of 6 ms when the terminal  310  receives the instruction of the plurality of PDCCH orders: According to the existing operation, the delay of 6 ms is minimally required until the RAP is transmitted at the time point when the PDCCH order is received. However, this takes into account the time when the terminal  310  is required to receive the PDCCH order, to understand the received information (about 3-4 ms), and to transmit the preamble to the indicated mask index. Therefore, if the same preamble is used, only a delay time (i.e., time when the terminal  310  receives the PDCCH order and checks the received information) of at least 3 to 4 ms may be considered. However, if different preambles are used every PDCCH order, a delay of 6 ms will be required as well. If the PDCCH order is transmitted every different ccs, the following operations of the terminal  310  may be defined. 
         [0259]    a) If before one RAR timer expires in the cell belonging to the same timing advance group (TAG) or the same random access group (RAG), a new PDCCH order is indicated for the cell and is the same as the preamble ID indicated by the previous PDCCH order, the terminal  310  may transmit the RAP to the base station  320  after a reduced delay time (e.g., 3 ms). 
         [0260]    b) If before one RAR timer expires in the cell belonging to the same TAG or the same RAG, the new PDCCH order is indicated for the cell and is different from the preamble ID indicated by the previous PDCCH order, the terminal  310  may transmit the RAP to the base station  320  after a normal delay time (e.g., 6 ms). 
         [0261]    c) When the RA procedure is in progress by PDCCH order in TAG 1 or RAG 1, if a new PDCCH order is indicated for a cell belonging to another TAG 2 or RAG 2 and is the same as the preamble ID indicated by the previous PDCCH order, the terminal  310  may transmit the RAP to the base station  320  after the normal delay time (e.g., 6 ms). At this time, the previous RA procedure is maintained in TAG1 or RAG1. 
         [0262]    d) When the RA procedure is in progress by PDCCH order in TAG 1 or RAG 1, if a new PDCCH order is indicated for a cell belonging to another TAG 2 or RAG 2 and is different from the preamble ID indicated by the previous PDCCH order, the terminal  310  may transmit the RAP to the base station  320  after the normal delay time (e.g., 6 ms). At this time, the previous RA procedure ends. 
         [0263]    Operation related to a delay of 6 ms when the terminal  310  receives the instruction of one PDCCH order: A method of transmitting, by a terminal  310 , RAP to a plurality of ccs by one PDCCH order may be considered in order to reduce a delay. According to the existing method, one PDCCH order may instruct the terminal  310  to provide cc intended by the base station by a CIF. If the new PDCCH order format is used, the base station  320  may directly instruct the plurality of ccs and their order to transmit the RAP to the terminal  310  in parallel. If the existing PDCCH order format is reused, the terminal  310  may perform the parallel RAP transmission in order for the activated cc within the TAG or RAG according to a predefined or RRC configurable rule. If the PRACH configuration for each cc is possible, the terminal  310  may selectively perform the RAP transmission only for the cc for which the PRACH configuration is completed. Meanwhile, it should be defined whether the terminal  310  performing the RAP transmission in one cc starts the RAP transmission in the next cc. The options for the procedure may include at least one of the following. a) The terminal  310  tries to transmit the RAP transmission for the fastest PRACH resource set in one cc and moves to the cc of the just next order to prepare the RAP transmission. b) If the LBT for the RAP transmission fails in one cc, the terminal  310  moves to the cc in the just next order and prepares for RAP transmission. c) If the RAP transmission starts in one cc and the set timer expires, the terminal  310  moves to the cc in the next order and prepares for the RAP transmission. d) If the RAP transmission starts in one cc and the LBT try fails k times, the terminal  310  moves to the cc in the next order and prepares for RAP transmission. e) If the RAP transmission starts in one cc and all the possible PRACH resources instructed by one PRACH configuration fails, the terminal  310  moves to the cc in the next order and prepares for the RAP transmission. e) If the terminal  310  tries to transmit the RAP transmission in the earliest next PRACH resource among the plurality of ccs and is assigned the PRACH resource in the same subframe in the plurality of ccs, it tries the RAP transmission in the cc having the lowest SCell index. 
         [0264]    If there is one MAC instance for the plurality of PDCCH orders: 
         [0265]    a) Only the preamble ID and the mask index indicated by the PDCCH order among the previous RAP transmission variables (e.g., preamble ID, mask index, RAR window, backoff index, maximum retry number, etc.) are updated to the contents of the new PDCCH order, and other variables may be maintained. 
         [0266]    b) The preamble ID and the mask index indicated by the PDCCH order among the previous RAP transmission variables (e.g., preamble ID, mask index, RAR window, backoff index, maximum retry number, etc.) are updated to the contents of the new PDCCH order, and the RAR window may also start newly. The backoff index and the maximum retry number may be maintained. 
         [0267]    c) The preamble ID and the mask index instructed by the PDCCH order among the previous RAP transmission variables (e.g., preamble ID, mask index, RAR window, backoff index, the maximum retry number, etc.) are updated to the contents of the new PDCCH order, and the RAR window and the maximum retry number may start newly. The backoff index may be maintained. 
         [0268]    d) The preamble ID and the mask index indicated by the PDCCH order among the previous RAP transmission variables (e.g., preamble ID, mask index, RAR window, backoff index, maximum retry number, etc.) are updated to the contents of the new PDCCH order, and all the remaining variables may also be updated and initialized. 
         [0269]    If there are a plurality of MAC instances for the plurality of PDCCH orders: If the new PDCCH order is received, 
         [0270]    a) Copy and operate the remaining parameters except the preamble ID, the mask index among the RAP transmission parameters of the previous PDCCH order. 
         [0271]    b) Copy and operate the remaining parameters except the preamble ID, the mask index, and the RAR window among the RAP transmission parameters of the previous PDCCH order. 
         [0272]    c) Copy and operate the remaining parameters except the preamble ID, the mask index, the RAR window, and the maximum retry number among the RAP transmission parameters of the previous PDCCH order. 
         [0273]    d) Operate depending on all parameters of the new PDCCH order without copying the RAP transmission parameter of the previous PDCCH order. 
         [0274]    Meanwhile, when the RA process including RAP and RAR is performed in parallel on the plurality of PDCCH orders, if the terminal  310  succeeds in receiving any one of the RARs, the remaining RA process may be terminated. 
         [0275]    [HARQ-ACK/NACK Report Method] 
         [0276]    In order to overcome the failure due to the LBT operation in the unlicensed band and successfully transmit the HARQ-ACK/NACK signal, there is a need to increase the success probability by trying the LBT several times to assign a plurality of redundant resources and to perform the HARQ-ACK/NACK signal. To this end, the base station  320  may assign 1) the HARQ-ACK resource to the terminal  310  in a plurality of ccs or 2) the HARQ-ACK resource to the plurality of subframes. 
         [0277]    In the case of 1) the method for assigning the HARQ-ACK resource in the plurality of ccs, according to the embodiment, a fixed delay of 4 ms between the DL data and the HARQ-ACK may be maintained. However, 1-a) the terminal  310  may try the LBT in the plurality of ccs and transmit all the HARQ-ACK in the succeeding cc, but in this case, if all succeed in the ccs larger than 3, it may not be transmitted simultaneously due to the implementation limitation of the terminal  310 . Therefore, the HARQ-ACK is transmitted only from cc having the lowest index to the maximum possible number of ccs, among the succeeding ccs and the HARQ-ACK signal may not be deliberately transmitted in the exceeding cc. In this case, the cc that does not deliberately transmit a signal may be considered as if the LBT fails. That is, if the terminal  310  performs the LBT result report operation, it may report the data assigned to the subframe that does not transmit the signal on purpose, including information on the LBT failure. According to another embodiment, 1-b) the terminal  310  may try the LBT in the plurality of ccs and may transmit the HARQ-ACK only in one of the succeeding ccs. In this case, in order for the base station  320  to identify the HARQ-ACK for the DL data in a certain cc, the terminal  310  may transmit the HARQ-ACK signal using the UCI format 3 which may express HARQ-ACK for up to five ccs. The five ccs of the format 3 represent the SCells sequentially increasing from the SCell index having a lower order within one UCI cell group. According to one embodiment, one of the five HARQ-ACKs of the format 3 is assigned for the LBT result report and the remaining may be assigned to the HARQ-ACK for four ccs. 
         [0278]    In the case of the 2) method for assigning HARQ-ACK resources to a plurality of subframes, the case where the HARQ-ACK resources are assigned to a plurality of subframes that are consecutive in time for minimizing the delay may be considered first. According to one embodiment, when the LBT fails in the first two subframes when four consecutive UL subframes corresponding to four DL subframes are assigned to maintain a delay of 4 ms from each DL subframe, if the LBT fails in the first two subframes, the terminal  310  may collect and transmit the HARQ-ACKs, that have to be transmitted in the first and second subframes, in the third subframe. To this end, in order for the base station  320  to identify the HARQ-ACK for the DL data in a certain subframe, the terminal  310  may transmit the HARQ-ACK signal using the UCI format 3 which may express the HARQ-ACK for up to five ccs. The five HARQ-ACKs of the format 3 may sequentially correspond to the consecutive UL subframes assigned as the multi-subframes. According to one embodiment, one of the five HARQ-ACKs of the format 3 is assigned for the LBT result report and the remaining may be assigned as the HARQ-ACK for four subframes. 
       CSI Report Method 
       [0279]    Unlike the HARQ-ACK, the channel state information (CSI) report is somewhat free from the limitations of performing the report after a fixed time interval compared to the subframe receiving the DL data. Thus, as if the CSI resource is periodically assigned to the existing PUCCH, the CSI resource may be assigned to potential periodical location in the unlicensed band SCell. The existing CSI report period may be set depending on CQI/precoding matrix indicator (PMI), and rank indication (RI), and according to FDD and TDD. In the same way, the base station  320  may set the report location to the terminal  310 , but may not set the LBT. The terminal  310  may transmit the CSI report to the base station  320  in the resource only when the resource is made by the UL grant and the allocated resource matches the periodic report location. The location of the frequency resource block in the subframe may be indicated in advance according to the CSI report setting. The terminal  310  may transmit the CSI report information to the base station  320  in the UCI multiplexing scheme if data are transmitted from the PUSCH resource to the UL-shared channel (UL-SCH) notwithstanding that the UCI report transmission is not specified in the UL grant separately. Meanwhile, since the report fails depending on the LBT result, in order to overcome the problem, a) the terminal  310  may report the CSI in all assigned subframes, or b) the terminal  310  may also perform the CSI report in the subframe of the report location and in the multi-subframe assigned thereafter. 
         [0280]    Meanwhile, according to the embodiment, the terminal  310  may also determine the potential LBT location depending on the configuration by the RRC message for the CSI report. If the terminal  310  determines various LBT locations depending on the CQI/PMI and RI report period settings to assign the multi-subframe by the UL grant, the terminal  310  may know in which subframe in the multi-subframe the LBT needs to be performed. 
         [0281]      FIG. 21  is a diagram illustrating a configuration of the terminal according to an embodiment of the present disclosure. 
         [0282]    Referring to  FIG. 21 , the terminal  310  according to one embodiment of the present disclosure may include a transceiver  310  and a controller  2120  controlling the overall operation of the terminal  310 . Further, the transceiver  2110  may include a transmitter  2115  and a receiver  2117 . 
         [0283]    The transceiver  2110  may transmit and receive a signal to and from other network entities. 
         [0284]    The controller  2120  may control the terminal  310  to perform any one operation of the above-described embodiments. For example, the controller  2120  may perform a control to receive from the base station  320  the resource assignment information including the information indicating at least two consecutive uplink subframes that may communicate through the unlicensed band, check whether at least one of the at least two consecutive uplink subframes is occupied, and if it is determined that the at least one uplink subframe is occupied, transmit the uplink data to the base station  320  during the at least uplink subframe. 
         [0285]    Meanwhile, the controller  2120  and the transceiver  2110  are not necessarily implemented as a separate module but may be implemented as one component in a form like a single chip. Further, the controller  2120  and the transceiver  2110  may be electrically connected to each other. 
         [0286]    Further, for example, the controller  2120  may be a circuit, an application-specific circuit, or at least one processor. In addition, the operations of the terminal  310  may be realized by including a memory device storing the corresponding program code in any component of the terminal. That is, the controller  2120  may execute the above-described operations by reading and executing the program code stored in the memory device by a processor, a central processing unit (CPU) or the like. 
         [0287]      FIG. 22  is a diagram illustrating a configuration of the base station according to an embodiment of the present disclosure. 
         [0288]    Referring to  FIG. 22 , the base station  320  according to one embodiment of the present disclosure may include a transceiver  2210  and a controller  2220  controlling the overall operation of the terminal  310 . Further, the transceiver  2210  may include a transmitter  2215  and a receiver  2217 . 
         [0289]    The transceiver  2210  may transmit and receive a signal to and from other network entities. 
         [0290]    The controller  2220  may control the base station  320  to perform any one operation of the above-described embodiments. For example, the controller  2220  may perform a control to generate resource assignment information including information of an uplink burst including at least two consecutive uplink subframes that may communicate through the unlicensed band, transmit the resource assignment information to the terminal  310 , and receive the uplink data from the terminal  310  during the at least two consecutive UL subframes. 
         [0291]    Meanwhile, the controller  2220  and the transceiver  2210  are not necessarily implemented as a separate module but may be implemented as one component in a form like a single chip. Further, the controller  2220  and the transceiver  2210  may be electrically connected to each other. 
         [0292]    Further, for example, the controller  2220  may be a circuit, an application-specific circuit, or at least one processor. In addition, the operations of the base station  320  may be realized by including a memory device storing the corresponding program code in any component of the UE. That is, the controller  2220  may execute the above-described operations by reading and executing the program code stored in the memory device by a processor, a CPU or the like. 
         [0293]    It should be noted that the examples of the methods and apparatuses illustrated by  FIGS. 1 to 22  are not intended to limit the scope of the present disclosure. That is, it should not be construed that all the components, entities, or operations described in  FIGS. 1 to 22  described above are indispensable elements for carrying out the disclosure, but they may be implemented within a range departing from the subject of the present disclosure even when the present disclosure includes only some components. 
         [0294]    The operations of the base station  320  and the terminal  310  described above may be realized by including the memory device storing the corresponding program code in any component in the base station  320  or the terminal  310 . That is, the controller  2120  of the base station  320  or the controller  2220  of the terminal  310  may execute the above-described operations by reading and executing the program code stored in the memory device by the processor and the CPU. 
         [0295]    Various components, modules, etc., of the entity, the base station  320 , or the terminal  310  described herein may also be operated using hardware circuits, for example, a complementary metal oxide semiconductor (CMOS) based logic circuit, hardware circuits such as firmware, software, and/or a combination of the hardware and the firmware and/or software embedded in a machine-readable medium. For example, various electrical structures and methods may be performed using electrical circuits such as transistors, logic gates, and an application-specific integrated circuit. 
         [0296]    While the present disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.