KR20190017492A - Method, apparatus, and system for uplink data transmission without grant in wireless communication system - Google Patents

Abstract

The present invention provides a method of allowing a terminal to set a hybrid-automatic repeat and request (HARQ) process ID to retransmit a transport block (TB) transmitted without a grant in a wireless communication system and a method for a terminal operation when a HARQ process ID collision occurs. In a method for determining a HARQ process ID, as a technical aspect of the present invention, a terminal and a base station statically predetermine some HARQ process IDs or dynamically determines some HARQ process IDs depending on whether HARQ process IDs are used.

Description

TECHNICAL FIELD [0001] The present invention relates to a grantless uplink transmission method, apparatus, and system in a wireless communication system,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system, and more particularly, to a method of grant-based retransmission of data transmitted in a wireless communication system without a grant.

3GPP LTE (-A) defines uplink / downlink physical channels for physical layer signal transmission. For example, a physical uplink shared channel (PUSCH) which is a physical channel for transmitting data in the uplink, a physical uplink control channel (PUCCH) for transmitting a control signal, and a physical random access channel (PRACH) A physical downlink shared channel (PDSCH) for transmitting data in downlink, a physical control format indicator channel (PCFICH), a physical downlink control channel (PDCCH), a physical hybrid ARQ indicator channel (PHICH) ).

A downlink control channel (PDCCH / EPDCCH) of the channels is a channel for transmitting uplink / downlink scheduling assignment control information, uplink transmission power control information, and other control information to one or a plurality of terminals. Since there is a limitation on the resources available for the PDCCH that can be transmitted at one time, it is not possible to allocate different resources to each terminal, and the control information should be transmitted to any terminal by sharing resources. For example, in 3GPP LTE (-A), four Resource Elements (REs) are grouped together to form REGs (Resource Element Groups), nine CCEs (Control Channel Elements), and one or a plurality of CCEs And informs the UE of a resource, and a plurality of UEs can share the CCE. Here, the number of CCEs to be combined is called CCE coupling level, and the resource to which CCE is allocated according to the possible CCE coupling level is called a search space. The search space may include a common search space defined for each base station and a terminal-specific or UE-specific search space defined for each terminal. The UE performs decoding on the number of possible CCE combining cases in the search space and can determine whether it corresponds to its own PDCCH through a user equipment (UE) identifier included in the PDCCH. Therefore, it takes a long time to decode the PDCCH and energy consumption is inevitable.

Efforts are underway to develop an improved 5G or pre-5G communication system to meet the growing demand for wireless data traffic after commercialization of the 4G communication system. For this reason, a 5G communication system or a pre-5G communication system is called a system after a 4G network (Beyond 4G network) communication system or after a LTE system (Post LTE). To achieve a high data rate, 5G communication systems are being considered for implementation in very high frequency (mmWave) bands (e.g., 60 gigahertz (60GHz) bands). In order to mitigate the path loss of the radio wave in the very high frequency band and to increase the propagation distance of the radio wave, in the 5G communication system, beamforming, massive MIMO, full-dimension MIMO (FD-MIMO ), Array antennas, analog beam-forming, and large scale antenna technologies are being discussed. In order to improve the network of the system, the 5G communication system has developed an advanced small cell, an advanced small cell, a cloud radio access network (cloud RAN), an ultra-dense network, (D2D), a wireless backhaul, a moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Have been developed. In addition, in the 5G system, the Advanced Coding Modulation (ACM) scheme, Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), the advanced connection technology, Filter Bank Multi Carrier (FBMC) (non-orthogonal multiple access), and SCMA (sparse code multiple access).

On the other hand, the Internet is evolving into an Internet of Things (IoT) network in which information is exchanged between distributed components such as objects in a human-centered connection network where humans generate and consume information. IoE (Internet of Everything) technology, which combines IoT technology with big data processing technology through connection with cloud servers, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired / wireless communication, network infrastructure, service interface technology and security technology are required. In recent years, sensor network, machine to machine , M2M), and MTC (Machine Type Communication). In the IoT environment, an intelligent IT (Internet Technology) service can be provided that collects and analyzes data generated from connected objects to create new value in human life. IoT is a field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, and advanced medical service through fusion of existing information technology . ≪ / RTI >

Accordingly, various attempts have been made to apply the 5G communication system to the IoT network. For example, technologies such as a sensor network, a machine to machine (M2M), and a machine type communication (MTC) are implemented by techniques such as beamforming, MIMO, and array antennas It is. The application of the cloud RAN as the big data processing technology described above is an example of the convergence of 5G technology and IoT technology.

Generally, a mobile communication system has been developed to provide voice service while ensuring the user's activity. However, the mobile communication system is gradually expanding not only to voice but also to data service, and now it has developed to the extent of providing high-speed data service. However, in a mobile communication system in which a service is currently provided, a lack of resources and users demand higher speed services, and therefore, a more advanced mobile communication system is required.

As mentioned earlier, future 5G technologies require lower latency data transmission due to the emergence of new applications such as real-time control and tactile internet, The delay is expected to be reduced to 1ms. 5G aims to provide a data delay that is about 10 times lower than the conventional one. To solve this problem, 5G is expected to propose a communication system using a mini-slot having a shorter TTI period (e.g., 0.2ms) in addition to the existing slot (or subframe).

When uplink transmission is required in LTE, the MS uses a physical random access channel (PRACH) channel when it transmits a scheduling request (SR) signal to an uplink control channel or when there is no uplink control channel for SR. Upon receiving the SR signal of the UE, the Node B transmits an UL grant for uplink data transmission to the UE, and the UE performs uplink transmission by receiving the UL grant. In the UL grant, HARQ procss IDs (or HARQ process numbers) are transmitted together for future HARQ retransmissions. The terminal maps a transport block (TB) transmitted with the corresponding UL grant to a corresponding HARQ process ID. This transmission scheme is called a grant-based (GB) transmission scheme. However, this scheme is not suitable for data requiring low latency since the UE transmits the SR and receives the UL grant and transmits the UL data signal. Therefore, there is a grant-free (GF) transmission scheme for transmitting data in the uplink without UL grant. For the GF transmission scheme, the base station can allocate a time-frequency resource for GF transmission to the mobile station using an RRC signal or an L1 signal. If there is a TB that needs to be transmitted in the GF transmission scheme, the UE can transmit the TB to the allocated time-frequency resource. At this time, the UE transmits a demodulation reference signal (DMRS) corresponding to its own unique ID (for example, C-RNTI) to check whether the UE has performed the GF transmission. If the Node B knows which UE has performed the GF transmission but fails to receive the TB, the UE transmits an UL grant to the UE, and if the UE receives the UL grant, the UE can retransmit the TB transmitted in the GF mode through the GB transmission. In the UL grant, the HARQ process ID is used in the UL grant to inform the UE whether the TB requesting the GF is a TB transmitted.

In the 3GPP NR system, a mobile station can perform uplink transmission with a predetermined time-frequency resource without receiving a grant from a base station. A first problem to be solved by the present invention is a method for determining a HARQ process ID of a TB to be transmitted without grant when a UE transmits an uplink without receiving a grant. If the HARQ process ID is set, the Node B can request the UE by granting UL grant to the UE for retransmission of the TB to be transmitted without the grant.

A second problem to be solved by the present invention is to define a UE operation when a HARQ process ID of a TB transmitted without a grant is already used as a HARQ process ID of another TB, .

The objects that can be achieved by the present invention are not limited to those specifically described herein.

According to an aspect of the present invention, there is provided a method of defining HARQ process IDs assignable to a TB to transmit without grant, the method comprising the steps of: determining a number of HARQ process IDs statistically, The present invention relates to a HARQ process ID determination method dynamically determined according to whether an ID is used or not.

According to another technical aspect of the present invention, there is provided a method for transmitting a HARQ process ID associated with a TB to be transmitted by a UE together with an uplink transmission without a grant when the UE transmits the uplink without granting To an HARQ process ID transmitting method of a terminal.

According to another aspect of the present invention, there is provided a method for transmitting a UL grant for retransmission of a TB transmitted without grant by a Node B to a Node B in a different RNTI than the UE-specific RNTI To a method of transmitting a HARQ process ID of a base station.

According to another technical aspect of the present invention, a UE determines whether a scheduled HARQ process ID included in a grant received from a Node B for scheduling is related to a TB transmitted by a UE without granting a grant, the UE selects a TB to be transmitted between the UE and the TB and transmits the selected TB information to the BS through a PUCCH, a PUSCH, or a DMRS, which is an uplink channel, will be.

It will be understood by those skilled in the art that various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from the following detailed description of the invention, do.

According to an embodiment of the present invention, a UE can perform uplink transmission without granting a transport block (TB) without HARQ process ID collision and transmit the corresponding TB in a grant-based uplink transmission. Therefore, it is possible to improve the reliability of the corresponding TB because HARQ combining is possible, and it is also possible to prevent repeated transmission without granting the corresponding TB.

1 shows an example of a radio frame structure used in a wireless communication system.
2 shows an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system.
3 is a view for explaining a physical channel used in a 3GPP system and a general signal transmission method using the same.
FIG. 4 illustrates a radio frame structure for transmission of a synchronization signal (SS).
5 is a diagram illustrating a structure of a downlink radio frame used in an LTE system.
6 illustrates a configuration of a cell specific common reference signal.
FIG. 7 shows an example of a UL subframe structure used in a wireless communication system.
8 is a conceptual diagram illustrating a carrier aggregation (CA) technique.
FIG. 9 is a diagram for explaining Single Carrier Communication and Multiple Carrier Communication. FIG.
10 is a diagram showing an example in which a cross carrier scheduling technique is applied.
11 is a diagram illustrating a deployment scenario of a UE and a BS in an LTE and LAA service environment.
12 is a block diagram showing the configuration of a terminal and a base station according to an embodiment of the present invention.
FIG. 13 is a flow chart for retransmission according to the grant of a TB to be transmitted without a grant.
FIG. 14 is a flowchart for monitoring the grant of a TB to be transmitted without a grant.
FIG. 15 is a diagram showing the HARQ process ID and the NDI value of a TB grant transmitted without grant.
FIG. 16 is a diagram showing scrambling of grants of TBs to be transmitted without grants to other RNTIs. FIG.
17 is a diagram showing a case where a plurality of TBs to be transmitted without a grant are provided.
18 is a diagram for monitoring TB to be transmitted without a grant.
FIG. 19 is a diagram showing an operation when there is a HARQ-ACK of a TB to be transmitted without a grant.
20 is a diagram illustrating that a UE transmits a HARQ process ID together with a TB transmitted without grant.
FIG. 21 is a diagram illustrating that a UE selects and transmits a TB transmitted without a grant and a TB transmitted according to a grant when an UL grant is given.

As used herein, terms used in the present invention are selected from general terms that are widely used in the present invention while taking into account the functions of the present invention. However, these terms may vary depending on the intention of a person skilled in the art, custom or the emergence of new technology. Also, in certain cases, there may be a term arbitrarily selected by the applicant, and in this case, the meaning thereof will be described in the description of the corresponding invention. Therefore, it is intended that the terminology used herein should be interpreted relative to the actual meaning of the term, rather than the nomenclature, and its content throughout the specification.

Throughout the specification, when a configuration is referred to as being "connected" to another configuration, it is not limited to the case where it is "directly connected," but also includes "electrically connected" do. Also, when an element is referred to as " including " a specific element, it is meant to include other elements, rather than excluding other elements, unless the context clearly dictates otherwise. In addition, the limitations of " above " or " below ", respectively, based on a specific threshold value may be appropriately replaced with "

FIG. 1 shows an example of a radio frame structure used in a wireless communication system.

Particularly, FIG. 1 (a) shows a frame structure for a frequency division duplex (FDD) used in a 3GPP LTE / LTE-A system and FIG. 1 Time division duplex (TDD) frame structure.

Referring to FIG. 1, a radio frame used in the 3GPP LTE / LTE-A system has a length of 10 ms (307200 Ts) and is composed of 10 equal sized subframes (SF). 10 subframes within one radio frame may be assigned respective numbers. Here, Ts represents the sampling time, and is represented by Ts = 1 / (2048 * 15 kHz). Each subframe is 1 ms long and consists of two slots. 20 slots in one radio frame can be sequentially numbered from 0 to 19. [ Each slot has a length of 0.5 ms. The time for transmitting one subframe is defined as a Transmission Time Interval (TTI). The time resource may be classified by a radio frame number (or a radio frame index), a subframe number (also referred to as a subframe number), a slot number (or a slot index), and the like.

The wireless frame may be configured differently according to the duplex mode. For example, in the FDD mode, since the downlink transmission and the uplink transmission are divided by frequency, the radio frame includes only one of the downlink subframe and the uplink subframe for a specific frequency band. In the TDD mode, since the downlink transmission and the uplink transmission are divided by time, the radio frame includes both the downlink subframe and the uplink subframe for a specific frequency band.

Table 1 illustrates the DL-UL configuration of subframes in a radio frame in TDD mode.

In Table 1, D denotes a downlink subframe, U denotes an uplink subframe, and S denotes a special subframe. The specific subframe includes three fields of Downlink Pilot Time Slot (DwPTS), Guard Period (GP), and UpPTS (Uplink Pilot Time Slot). DwPTS is a time interval reserved for downlink transmission, and UpPTS is a time interval reserved for uplink transmission. Table 2 illustrates the configuration of the singular frames.

2 illustrates an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system. In particular, Figure 2 shows the structure of the resource grid of the 3GPP LTE / LTE-A system. There is one resource grid per antenna port. Referring to FIG. 2, a slot includes a plurality of OFDM symbols in a time domain and a plurality of resource blocks (RB) in a frequency domain. The OFDM symbol also means one symbol period. Referring to FIG. 2, a signal transmitted in each slot may be expressed as a resource grid consisting of N ^{DL / UL} _RB * N ^RB _sc subcarriers and N ^{DL / UL} _symb OFDM symbols. have. Here, N ^DL _RB represents the number of resource blocks (RBs) in the downlink slot, and N ^UL _RB represents the number of _RBs in the UL slot. N ^DL _RB and N ^UL _RB depend on the DL transmission bandwidth and the UL transmission bandwidth, respectively. N ^DL _symb denotes the number of OFDM symbols in the downlink slot, and N ^UL _symb denotes the number of OFDM symbols in the UL slot. N ^RB _sc represents the number of subcarriers constituting one RB. The OFDM symbol may be referred to as an OFDM symbol, an SC-FDM (Single Carrier Frequency Division Multiplexing) symbol, or the like according to a multiple access scheme. The number of OFDM symbols included in one slot can be variously changed according to the channel bandwidth and the length of the cyclic prefix (CP). For example, in the case of a normal CP, one slot includes 7 OFDM symbols

In the case of an extended CP, one slot includes six OFDM symbols. Although FIG. 2 illustrates a subframe in which one slot is composed of seven OFDM symbols for convenience of description, embodiments of the present invention may be applied to subframes having a different number of OFDM symbols in a similar manner. Referring to FIG. 2, each OFDM symbol includes N ^{DL / UL} _RB * N ^RB _sc subcarriers in the frequency domain. The type of subcarrier may be a data subcarrier for data transmission, a reference signal subcarrier for transmission of a reference signal, a null subcarrier for a guard band or a direct current (DC) ≪ / RTI > The DC component is mapped to a carrier frequency (f ₀ ) in an OFDM signal generation process or a frequency up-conversion process. The carrier frequency is also referred to as the center frequency (f _c ).

One RB is defined as N ^{DL / UL} _symb consecutive OFDM symbols in the time domain (for example, seven), and N ^RB _scrambled (e.g., twelve) consecutive subcarriers in the frequency domain . For reference, a resource composed of one OFDM symbol and one subcarrier is referred to as a resource element (RE) or tone. Therefore, one RB consists of N ^{DL / UL} _symb * N ^RB _sc resource elements. Each resource element in the resource grid can be uniquely defined by an index pair (k, 1) in one slot. k is an index assigned from 0 to N ^{DL / UL} _RB * N ^RBsc -1 in the frequency domain, and 1 is an index assigned from 0 to N ^{DL / UL} _symb -1 in the time domain.

One RB is mapped to one physical resource block (PRB) and one virtual resource block (VRB). The PRB is defined as N ^{DL / UL} _symb (e.g., 7) consecutive OFDM symbols or SC-FDM symbols in the time domain, and N ^RB _scrambled (e.g., twelve) Is defined by the subcarrier. Therefore, one PRB consists of N ^{DL / UL} _symb * N ^RB _sc resource elements. Two RBs, one in each of two slots of the subframe occupying N ^RB _sc consecutive identical subcarriers in one subframe, are called a PRB pair. The two RBs constituting the PRB pair have the same PRB number (or PRB index).

In order for the UE to receive a signal from the eNB or to transmit a signal to the eNB, the time / frequency synchronization of the UE should be synchronized with the time / frequency synchronization of the eNB. since it can determine the time and frequency parameters necessary for the UE to perform the demodulation of the DL signal and the transmission of the UL signal at the correct time, as long as it is synchronized with the eNB.

3 is a view for explaining a physical channel used in a 3GPP system and a general signal transmission method using the same.

The terminal performs an initial cell search operation such as synchronizing with a base station when power is increased or newly enters a cell (S301). To this end, the terminal receives a primary synchronization channel (P-SCH) and a secondary synchronization channel (S-SCH) from a base station and synchronizes with the base station and acquires information such as a cell ID have. Then, the terminal can receive the physical broadcast channel from the base station and acquire the in-cell broadcast information. Meanwhile, the UE can receive the downlink reference signal (DL RS) in the initial cell search step to check the downlink channel state.

Upon completion of the initial cell search, the UE receives more detailed system information by receiving a Physical Downlink Control Channel (PDCCH) and a Physical Downlink Control Channel (PDSCH) according to the information on the PDCCH (S302).

On the other hand, if the base station is initially connected or there is no radio resource for signal transmission, the terminal can perform a random access procedure (RACH) on the base station (steps S303 to S306). To this end, the UE transmits a specific sequence through a Physical Random Access Channel (PRACH) (S303 and S305), and receives a response message for the preamble on the PDCCH and the corresponding PDSCH S304 and S306). In case of the contention-based RACH, a contention resolution procedure can be additionally performed.

The UE having performed the procedure described above transmits PDCCH / PDSCH reception (S307) and physical uplink shared channel (PUSCH) / physical uplink control channel Control Channel, PUCCH) (S308). In particular, the UE receives downlink control information (DCI) through the PDCCH. Here, the DCI includes control information such as resource allocation information for the UE, and formats are different according to the purpose of use.

Meanwhile, the control information that the UE transmits to the base station through the uplink or receives from the base station includes a downlink / uplink ACK / NACK signal, a channel quality indicator (CQI), a precoding matrix index (PMI) ) And the like. In the case of the 3GPP LTE system, the UE can transmit control information such as CQI / PMI / RI as described above through PUSCH and / or PUCCH.

FIG. 4 illustrates a radio frame structure for transmission of a synchronization signal (SS). In particular, FIG. 4 illustrates a radio frame structure for transmission of a synchronous signal and a PBCH in a frequency division duplex (FDD). FIG. 4A illustrates a radio frame in a normal CP (normal cyclic prefix) SS and PBCH. FIG. 4 (b) shows transmission positions of SS and PBCH in a radio frame configured with an extended CP.

The UE obtains time and frequency synchronization with the cell when it is powered on or newly connected to the cell, and performs cell search such as detecting the physical cell identity N ^cell _ID of the cell cell search procedure. To this end, the UE receives a synchronization signal, for example, a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) from the eNB, synchronizes with the eNB, , ID) can be obtained.

Referring to FIG. 4, the SS will be described in more detail as follows. SS is divided into PSS and SSS. PSS is used to obtain time domain synchronization and / or frequency domain synchronization such as OFDM symbol synchronization, slot synchronization, and the like. SSS is used for frame synchronization, cell group ID, and / or cell CP configuration Information). Referring to FIG. 4, the PSS and the SSS are transmitted in two OFDM symbols of each radio frame, respectively. In order to facilitate inter Radio Access Technology ("RAT") measurement, the SS considers 4.6 ms, which is the Global System for Mobile communication (GSM) frame length, in the first slot of subframe 0 and the first slot of subframe 5 Respectively. Specifically, the PSS is transmitted in the last OFDM symbol of the first slot of the subframe 0 and the last OFDM symbol of the first slot of the subframe 5, respectively, and the SSS is transmitted from the second OFDM symbol at the end of the first slot of the subframe 0, Lt; RTI ID = 0.0 > OFDM < / RTI > The boundary of the corresponding radio frame can be detected through the SSS. The PSS is transmitted in the last OFDM symbol of the slot and the SSS is transmitted in the OFDM symbol immediately before the PSS. SS's transmit diversity scheme uses only a single antenna port and is not defined in the standard. That is, a single antenna port transmission or a UE transparent transmission scheme (e.g., Precoding Vector Switching (PVS), Time Switched Diversity (TSTD), Cyclic Delay Diversity (CDD)) can be used for SS transmission diversity .

The SS can represent a total of 504 unique physical layer cell IDs through a combination of three PSSs and 168 SSs. In other words, the physical layer cell IDs are allocated to 168 physical-layer cell-identifier groups, each group including three unique identifiers, such that each physical-layer cell ID is part of only one physical-layer cell- . Thus, the physical layer cell ID _{^{N cell ID = 3N (1)}} ID + N (2) ID is a physical-layer cell - the range of 0 [identifier group to the 167 number N ⁽¹⁾ _ID and the physical-layer cell - a unique number N ⁽²⁾ _ID of 0 to 2 indicating the physical-layer identifier in the identifier group. The UE may detect the PSS to know one of the three unique physical-layer identifiers and may detect the SSS to identify one of the 168 physical layer cell IDs associated with the physical-layer identifier. A ZC (Zadoff-Chu) sequence of length 63 is defined in the frequency domain and used as the PSS.

Referring to FIG. 4, since the PSS is transmitted every 5 ms, the UE can detect that the corresponding subframe is one of the subframe 0 and the subframe 5 by detecting the PSS. However, I do not know what it is. Therefore, the UE can not recognize the boundary of the radio frame only by the PSS. That is, frame synchronization can not be obtained with only PSS. The UE detects an SSS transmitted twice in one radio frame but transmitted as a different sequence and detects the boundary of the radio frame.

5 is a diagram illustrating a control channel included in a control region of one subframe in a downlink radio frame.

Referring to FIG. 5, a subframe is composed of 14 OFDM symbols. According to the subframe setting, the first to third OFDM symbols are used as a control region and the remaining 13 to 11 OFDM symbols are used as a data region. In the figure, R1 to R4 represent a reference signal (RS) or pilot signal for antennas 0 to 3. The RS is fixed in a constant pattern in the subframe regardless of the control region and the data region. The control channel is allocated to a resource to which the RS is not allocated in the control region, and the traffic channel is also allocated to the resource to which the RS is not allocated in the data region. Control channels allocated to the control region include a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid-ARQ Indicator CHannel (PHICH), and a Physical Downlink Control Channel (PDCCH).

The PCFICH informs the UE of the number of OFDM symbols used in the PDCCH for each subframe as a physical control format indicator channel. The PCFICH is located in the first OFDM symbol and is set prior to the PHICH and PDCCH. The PCFICH is composed of four REGs (Resource Element Groups), and each REG is distributed in the control area based on the cell ID (Cell IDentity). One REG is composed of four REs (Resource Elements). RE denotes a minimum physical resource defined by one subcarrier x one OFDM symbol. The PCFICH value indicates a value of 1 to 3 or 2 to 4 depending on the bandwidth and is modulated by Quadrature Phase Shift Keying (QPSK).

The PHICH is used as a physical HARQ (Hybrid Automatic Repeat and Request) indicator channel to carry HARQ ACK / NACK for uplink transmission. That is, the PHICH indicates a channel through which DL ACK / NACK information for UL HARQ is transmitted. The PHICH consists of one REG and is cell-specific scrambled. The ACK / NACK is indicated by 1 bit and is modulated by BPSK (Binary Phase Shift Keying). The modulated ACK / NACK is spread with a spreading factor (SF) = 2 or 4. A plurality of PHICHs mapped to the same resource constitute a PHICH group. The number of PHICHs multiplexed into the PHICH group is determined by the number of spreading codes. The PHICH (group) is repetitized three times to obtain the diversity gain in the frequency domain and / or the time domain.

The PDCCH is allocated to the first n OFDM symbols of the subframe as the physical downlink control channel. Here, n is an integer of 1 or more and is indicated by the PCFICH. The PDCCH consists of one or more CCEs. The PDCCH notifies each terminal or group of terminals of information related to resource allocation of a paging channel (PCH) and a downlink-shared channel (DL-SCH), an uplink scheduling grant, and HARQ information. A paging channel (PCH) and a downlink-shared channel (DLSCH) are transmitted on the PDSCH. Therefore, the BS and the MS generally transmit and receive data via the PDSCH, except for specific control information or specific service data.

PDSCH data is transmitted to a terminal (one or a plurality of terminals), and information on how the terminals receive and decode PDSCH data is included in the PDCCH and transmitted. For example, if a particular PDCCH is CRC masked with an RNTI (Radio Network Temporary Identity) of "A ", and a DCI format called " C" Assume that information on data to be transmitted using information (e.g., transport block size, modulation scheme, coding information, etc.) is transmitted through a specific subframe. In this case, the UE in the cell monitors the PDCCH using its RNTI information, and if there is more than one UE having the "A" RNTI, the UEs receive the PDCCH, B "and" C ".

FIG. 6 illustrates the configuration of a cell specific common reference signal. In particular, Figure 6 illustrates a CRS structure for a 3GPP LTE system supporting up to four antennas.

[Equation 1]

Where k is a subcarrier index, 1 is an OFDM symbol index, p is an antenna port number, and ^{Nmax and DL} _RB represent the largest downlink bandwidth configuration, expressed as an integer multiple of N ^RB _sc .

The variables v and v _shift define positions in the frequency domain for different RSs, and v is given by

&Quot; (2) "

Where n _s is the slot number in the radio frame and the cell specific frequency transition is given by:

&Quot; (3) "

Referring to FIG. 6 and Equations 1 and 2, the current 3GPP LTE / LTE-A standard defines a cell-specific CRS used for demodulation and channel measurement among the various RSs defined in the corresponding system, To be transmitted over the entire downlink band. Also, in the 3GPP LTE / LTE-A system, the cell-specific CRS is used for demodulation of the downlink data signal, and thus is transmitted every antenna port for downlink transmission.

Meanwhile, the cell-specific CRS can be used not only for channel state measurement and data demodulation, but also for tracking after the UE acquires time synchronization and frequency synchronization of a carrier used for communication with the UE, It is also used for tracking.

FIG. 7 shows an example of a UL subframe structure used in a wireless communication system.

Referring to FIG. 7, the UL subframe may be divided into a control domain and a data domain in the frequency domain. One or several physical uplink control channels (PUCCHs) may be assigned to the control region to carry uplink control information (UCI). One or several physical uplink shared channels (PUSCHs) may be allocated to the data area of the UL subframe to carry user data.

In the UL subframe, subcarriers far away from each other based on a DC (Direct Current) subcarrier are used as a control region. In other words, the subcarriers located at both ends of the UL transmission bandwidth are allocated for transmission of the UL control information. The DC subcarrier is a component that is left unused for signal transmission and is mapped to the carrier frequency f ₀ in the frequency up conversion process. In one subframe, the PUCCH for one UE is allocated to an RB pair belonging to resources operating at one carrier frequency, and RBs belonging to the RB pair occupy different subcarriers in two slots. The PUCCH allocated as described above is expressed as the RB pair allocated to the PUCCH is frequency hopped at the slot boundary. However, when frequency hopping is not applied, the RB pairs occupy the same subcarrier.

The PUCCH may be used to transmit the following control information.

- SR (Scheduling Request): Information used for requesting uplink UL-SCH resources. OOK (On-Off Keying) method.

- HARQ-ACK: A response to the PDCCH and / or a response to a downlink data packet (eg, codeword) on the PDSCH.

Indicates whether PDCCH or PDSCH has been successfully received. In response to a single downlink codeword, one bit of HARQACK is transmitted and two bits of HARQ-ACK are transmitted in response to two downlink codewords. The HARQ-ACK response includes positive ACK (simply ACK), negative ACK (NACK), DTX (Discontinuous Transmission) or NACK / DTX. Here, the term HARQ-ACK is mixed with HARQ ACK / NACK and ACK / NACK.

- CSI (Channel State Information): Feedback information for the downlink channel. Multiple Input Multiple Output (MIMO) -related feedback information includes RI (Rank Indicator) and PMI (Precoding Matrix Indicator).

Hereinafter, a carrier aggregation technique will be described. 8 is a conceptual diagram illustrating carrier aggregation.

Carrier aggregation is a technique in which a radio communication system uses a frequency block or a (logical sense) cell composed of uplink resources (or component carriers) and / or downlink resources (or component carriers) Which is used as a single large logical frequency band. Hereinafter, the term "component carrier" is used for the convenience of description.

Referring to FIG. 8, the total system bandwidth (System BW) has a bandwidth of 100 MHz as a logical bandwidth. The total system bandwidth includes five component carriers, each of which has a bandwidth of up to 20 MHz. A component carrier comprises one or more contiguous subcarriers physically contiguous. In FIG. 8, each of the component carriers is shown to have the same bandwidth, but this is merely an example, and each component carrier may have a different bandwidth. In addition, although each component carrier is shown as being adjacent to each other in the frequency domain, this figure is shown in a logical concept, wherein each component carrier may physically be adjacent to or spaced from one another.

The center frequency may use different common carriers for each component carrier or common for physically contiguous component carriers. For example, assuming that all of the component carriers are physically adjacent in FIG. 8, the center carrier A can be used. Further, assuming that the respective component carriers are not physically adjacent to each other, the center carrier A, the center carrier B, and the like can be used separately for each component carrier.

In this specification, the component carrier may correspond to the system band of the legacy system. By defining a component carrier based on a legacy system, it is possible to provide backward compatibility and system design in a wireless communication environment in which an evolved terminal and a legacy terminal coexist. In one example, if the LTE-A system supports carrier aggregation, each component carrier may correspond to the system band of the LTE system. In this case, the component carrier may have any of the following bandwidths: 1.25, 2.5, 5, 10, or 20 Mhz.

The frequency band used for communication with each terminal when the entire system band is expanded by carrier aggregation is defined in units of component carriers. Terminal A can use 100 MHz, which is the entire system band, and performs communication using all five component carriers. The terminals B1 to B5 can use only a 20 MHz bandwidth and perform communication using one component carrier. Terminals C ₁ and C ₂ can use a 40 MHz bandwidth and each communicate using two component carriers. The two component carriers may be logically / physically adjacent or non-contiguous. The terminal C ₁ shows a case in which two non-adjacent component carriers are used and the terminal C ₂ shows a case in which two adjacent component carriers are used.

In the LTE system, one downlink component carrier and one uplink component carrier are used, while in the LTE-A system, a plurality of component carriers can be used as shown in FIG. A combination of a downlink component carrier or a corresponding downlink component carrier and a corresponding uplink component carrier may be referred to as a cell and a corresponding relationship between a downlink component carrier and an uplink component carrier may be indicated through system information .

At this time, the scheme of scheduling the data channel by the control channel may be classified into a link carrier scheduling method and a cross carrier scheduling method.

More specifically, link carrier scheduling schedules data channels only through the particular component carrier, such as existing LTE systems that use a single component carrier, over a particular component carrier. That is, the downlink grant / uplink grant transmitted to the PDCCH region of the downlink component carrier of a specific component carrier (or specific cell) can be scheduled only for the PDSCH / PUSCH of the cell to which the corresponding downlink component carrier belongs. That is, the search space, which is an area for attempting to detect the downlink grant / uplink grant, exists in the PDCCH region of the cell where the PDSCH / PUSCH to be scheduled is located.

On the other hand, in the cross carrier scheduling, when a control channel transmitted through a primary component carrier (Primary CC) using a Carrier Indicator Field (CIF) is transmitted through the main component carrier or through another component carrier Schedules the channel. In other words, a monitored cell (Monitored Cell or Monitored CC) of the cross-carrier scheduling is set, and the downlink grant / uplink grant transmitted in the PDCCH region of the monitored cell is set to PDSCH / PUSCH of a cell set to be scheduled in the corresponding cell Scheduling. That is, a search area for a plurality of component carriers is present in a PDCCH area of a cell to be monitored. Among the plurality of cells, system information is transmitted, an initial access attempt is made, and the PCell is set by transmission of uplink control information. The PCell is a downlink main component carrier and an uplink main component carrier corresponding to the downlink main component carrier .

9 is a diagram for explaining single carrier communication and multiple carrier communication. Particularly, FIG. 9A shows a subframe structure of a single carrier and FIG. 9B shows a subframe structure of multiple carriers.

Referring to FIG. 9A, a general wireless communication system performs data transmission or reception (in a frequency division duplex (FDD) mode) through one DL band and one UL band corresponding thereto , A radio frame is divided into an uplink time unit and a downlink time unit in a time domain and data transmission or reception is performed through an uplink / downlink time unit (time division duplex , TDD) mode). However, in recent wireless communication systems, introduction of a carrier aggregation technique using a larger UL / DL bandwidth by collecting a plurality of UL and / or DL frequency blocks in order to use a wider frequency band is being discussed. Carrier aggregation is an orthogonal frequency division multiplexing (OFDM) scheme that performs DL or UL communication by putting a fundamental frequency band divided into a plurality of orthogonal subcarriers on one carrier frequency in that DL or UL communication is performed using a plurality of carrier frequencies division multiplexing system. Hereinafter, each of the carriers collected by carrier aggregation is referred to as a component carrier (CC). Referring to FIG. 9 (b), three 20 MHz CCs can be grouped into UL and DL, respectively, so that a bandwidth of 60 MHz can be supported. Each CC may be adjacent or non-adjacent to one another in the frequency domain. FIG. 9B shows a case where the bandwidth of the UL CC and the bandwidth of the DL CC are the same and symmetric, but the bandwidth of each CC can be determined independently. Asymmetric carrier aggregation in which the number of UL CCs is different from the number of DL CCs is also possible. A DL / UL CC specific to a particular UE may be referred to as a configured serving UL / DL CC in a particular UE.

The eNB may be used to communicate with the UE by activating some or all of the serving CCs configured in the UE, or by deactivating some CCs. The eNB can change the CC to be activated / deactivated, and can change the number of CCs to be activated / deactivated. When the eNB allocates a CC available for the UE in a cell-specific or UE-specific manner, at least one of the assigned CCs is used, as long as the CC allocation for the UE is not completely reconfigured or the UE does not perform a handover. One is not disabled. A CC that is not deactivated is referred to as a primary CC (PCC), and a CC that can be freely activated / deactivated by the eNB is called a secondary CC (SCC), unless it is a full reconfiguration of the CC assignment to the UE It is called. PCC and SCC may be distinguished based on control information. For example, specific control information may be set to be transmitted and received only via a specific CC, which may be referred to as PCC and the remaining CC (s) as SCC (s).

Meanwhile, 3GPP LTE (-A) uses the concept of a cell to manage radio resources. A cell is defined as a combination of DL resources and UL resources, that is, a combination of DL CC and UL CC. A cell may consist of DL resources alone, or a combination of DL resources and UL resources. If carrier aggregation is supported, the linkage between the carrier frequency of the DL resource (or DL CC) and the carrier frequency of the UL resource (or UL CC) . For example, a combination of a DL resource and a UL resource can be indicated by linkage of System Information Block Type 2 (SIB2). Here, the carrier frequency means a center frequency of each cell or CC. In the following,

a cell operating on a frequency is referred to as a primary cell or a PCC and a cell operating on a secondary frequency (or SCC) is referred to as a secondary cell (SCell) It is called. The carrier corresponding to PCell in the downlink is referred to as a downlink primary CC (DL PCC), and the carrier corresponding to PCell in the uplink is referred to as a UL primary CC (DL PCC). SCell refers to a cell that is configurable after a Radio Resource Control (RRC) connection is established and can be used to provide additional radio resources. Depending on the capabilities of the UE, a SCell may form together with the PCell a set of serving cells for the UE. The carrier corresponding to the SCell in the downlink is referred to as DL secondary CC (DL SCC), and the carrier corresponding to the SCell in the uplink is referred to as UL secondary CC (UL SCC)

do. For UEs that are in the RRC_CONNECTED state but no carrier aggregation is set or that do not support carrier aggregation, there is only one serving cell consisting of only PCell.

As previously mentioned, the term cell used in carrier aggregation is distinguished from the term cell, which refers to a geographical area in which a communication service is provided by a single eNB or a group of antennas. In order to distinguish between a cell designating a certain geographical area and a cell of carrier aggregation, a carrier aggregation cell is referred to as a CC and a cell in a geographical area is referred to as a cell. Quot;

In the existing LTE / LTE-A system, when multiple CCs are used together, it is assumed that the UL / DL frame time synchronization of the SCC coincides with the time synchronization of the PCC, assuming that the CCs that are not so far away in the frequency domain are clustered. However, there is a possibility that a plurality of CCs belonging to different frequency bands or spaced apart from each other in frequency, that is, a plurality of CCs having different propagation characteristics, may be gathered in the future. In this case, assuming that the time synchronization of the PCC and the time synchronization of the SCC are the same as in the conventional case, the synchronization of the DL / UL signal of the SCC may be seriously adversely affected.

Meanwhile, in the case of the LCT CC, among the radio resources operating in the LCT CC, radio resources available for transmission / reception of physical uplink / downlink channels and radio resources available for transmission / reception of physical uplink / The resources, as described above, are predetermined. In other words, the LCT CC is not configured to carry physical channels / signals through arbitrary time frequency in arbitrary time resources, but may be configured to transmit the physical channel / Signal should be configured to carry. For example, the physical downlink control channels may be configured only in the first OFDM symbol (s) of the OFDM symbols in the DL subframe, and the PDSCH may include the first OFDM symbol (s) that are likely to be mapped physical downlink control channels. Lt; / RTI > As another example, the CRS (s) corresponding to the antenna port (s) of the eNB are transmitted every subframe in the REs shown in Fig. 6 over the entire band regardless of the DL BW of the eNB. Accordingly, when the number of antenna ports of the eNB is 1, REs indicated by '0' in FIG. 6 are '0', '1', '2' and ' 3 'can not be used for other downlink signal transmission. In addition, there are various constraints on the composition of the LCT CC, and these constraints are greatly increased as the communication system develops. Some of these constraints arise because of the level of communication technology at the time the constraint is created, and there are some constraints that are unnecessary as communication technology develops, and constraints of existing and new technologies for the same purpose It may be present at the same time. As the constraints become so large, the constraints introduced for the development of the communication system are making the wireless resources of the CC ineffective. Therefore, the introduction of NCT CC, which can be constructed according to the simplified constraints rather than the existing constraints, is free from the constraints that are unnecessary according to the development of the communication technology. Since the NCT CC is not constructed according to the constraints of the existing system, it can not be recognized by the UE implemented according to the existing system. Hereinafter, UEs which are implemented according to the existing system and can not support NCT CC are called legacy UEs, and UEs implemented to support NCT CCs are called NCT UEs.

It is considered that NCT CC will be used as SCC in LTE-A system in the future. Since the NCT CC does not consider use by the legacy UE, the legacy UE does not need to perform cell search, cell selection, cell reselection, etc. in the NCT CC. If the NCT CC is not used as a PCC and the NCT CC is used only as an SCC, unnecessary constraints on the SCC can be reduced compared to an existing LCT CC that can be used as a PCC, enabling more efficient use of the CC. However, the time / frequency synchronization of the NCT CC may not coincide with the synchronization of the PCC. Even if the time / frequency synchronization of the NCT CC is obtained once, the time / frequency synchronization may be changed according to the change of the communication environment. An RS in which time synchronization and / or frequency synchronization can be used for tracking is required. An RS is also needed to allow the UE to detect the NCT CC in the neighbor cell search process. CRS can be used for purposes such as time / frequency synchronization of NCT CC and neighbor cell search using NCT CC. The CRS may be configured in the NCT CC in the same manner as in the existing LTE / LTE-A system shown in FIG. 6 and may have a smaller density in the time axis or frequency axis than the existing LTE / LTE- It may be configured in the NCT CC.

In the present invention, it is proposed that the CRS on the NCT CC is configured to have a lower density on the time axis than the CRS on the LCT CC of the existing LTE / LTE-A system. Accordingly, in the present invention, the NCT CC includes a constraint condition that the CRS is configured in the corresponding CC for every DL subframe, a constraint condition that the CRS is configured in the CC for each antenna port of the eNB, a predetermined number of OFDM It may not satisfy at least one of the constraint conditions that the symbol should be reserved for transmission of the control channel such as the PDCCH over the frequency band of the corresponding CC. For example, on the NCT CC, a CRS may be configured for every predetermined number (> 1) of subframes, not every subframe. Or, on the NCT CC, only the CRS for one antenna port (e.g., antenna port 0) can be configured regardless of the number of antenna ports of the eNB. The CRS of the present invention may not be used for data demodulation unlike the existing CRS shown in FIG. Therefore, instead of the existing CRS used for channel state measurement and demodulation, a tracking RS is newly defined for tracking of time synchronization and / or frequency synchronization, and the tracking RS is added to some subframes and / or some frequency resources on the NCT CC Lt; / RTI > Alternatively, the PDSCH may be configured in the leading OFDM symbols on the NCT CC, the PDCCH may be configured in the existing PDSCH region other than the initial OFDM symbols, or the PDCCH may be configured using some frequency resources. Hereinafter, unlike the existing LTE / LTE-A system, unlike the existing LTE / LTE-A system, the RSs transmitted in some subframes can be used in common by any UE regardless of the name, such as time synchronization and / or frequency synchronization of the NCT CC, RS (common RS, CRS).

10 is a diagram showing an example in which a cross carrier scheduling technique is applied. In particular, in FIG. 10, the number of allocated cells (or component carriers or component carriers) is three and the cross carrier scheduling technique is performed using CIF as described above. Here, it is assumed that the downlink cell # 0 is a downlink main component carrier (i.e., a primary cell, PCell) and the remaining component carriers # 1 and # 2 are subsidiary components (i.e., a secondary cell, SCell).

In the present invention, an effective management method of uplink resources for a main component carrier (primary component carrier, primary cell or PCell) or a subsidiary component carrier (secondary component carrier or secondary cell or SCell) during a carrier aggregation operation I suggest. Hereinafter, the case where the terminal operates by merging two component carriers is explained, but it is obvious that the present invention can also be applied to the case of merging three or more component carriers.

11 is a diagram illustrating a deployment scenario of a UE and a BS in an LTE and LAA service environment.

In the frequency band targeted by the LAA service environment, the wireless communication distance is not long due to the high frequency characteristics. In consideration of this, the deployment scenario between the terminal and the base station in the environment where the existing LTE-licensed service and the LAA service coexist is the overlay model shown on the left side of FIG. 11 and the overlay model shown in the right side of FIG. or a co-located model.

In the case of the overlay model shown in the left side of FIG. 11, the macro eNB performs wireless communication with the X terminal and the X 'terminal in the macro area 32 using a licensed carrier, and a plurality of RRHs and an X2 interface Lt; / RTI > Each RRH may perform wireless communication with an X terminal or an X 'terminal in a certain area 31 using an unlicensed carrier. In this case, there is no mutual interference between the macro eNB and the RRH. However, in order to use the LAA service as an auxiliary downlink channel of the LTE-licensed service through carrier aggregation, an X2 interface between the macro eNB and the RRH A fast data exchange should be made.

In the case of the co-located model shown on the right-hand side of FIG. 11, the pico / femto eNB can perform wireless communication with the Y terminal simultaneously using an authorized carrier and an unauthorized carrier. However, the use of the LTE service and the LAA service together is considered in the downlink data transmission. In this case, coverage for LTE service and coverage for LAA service may differ depending on frequency band, transmission power, and the like.

A terminal according to an embodiment of the present invention can be implemented by various types of wireless communication devices or computing devices that are guaranteed to be portable and mobility.

The base station according to the embodiment of the present invention controls and manages a cell (for example, a macro cell, a femtocell, a picocell, etc.) corresponding to a service area and transmits a signal, channel designation, channel monitoring, Can be performed.

12 is a block diagram showing the configuration of a terminal and a base station according to an embodiment of the present invention.

As shown, a terminal 100 according to an embodiment of the present invention may include a processor 110, a communication module 120, a memory 130, a user interface unit 140, and a display unit 150 have.

First, the processor 110 may execute various commands or programs, and may process data inside the terminal 100. [ In addition, the processor 100 can control the entire operation including each unit of the terminal 100, and can control data transmission / reception between the units.

Next, the communication module 120 may be an integrated module that performs wireless communication using a wireless communication network and wireless LAN connection using a wireless LAN. To this end, the communication module 120 may include a plurality of network interface cards such as the cellular communication interface cards 121 and 122 and the wireless LAN interface card 123, either internally or externally. 12, the communication module 120 is shown as an integrated integrated module, but each network interface card may be independently arranged according to the circuit configuration or use, unlike in FIG.

The cellular communication interface card 121 according to the first frequency band transmits and receives a radio signal with at least one of the base station 200, the external device, and the server using the mobile communication network, Band cellular communication service. Here, the wireless signal may include various types of data or information such as a voice call signal, a video call signal, or a text / multimedia message.

According to an embodiment of the present invention, the cellular communication interface card 121 by the first frequency band may include at least one NIC module using the LTE-Licensed frequency band. According to an embodiment of the present invention, at least one NIC module performs cellular communication with at least one of the base station 200, the external device, and the server independently in accordance with the cellular communication standard or protocol of the frequency band supported by the corresponding NIC module . The cellular communication interface card 121 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the terminal 100. [

The cellular communication interface card 122 in the second frequency band transmits and receives a radio signal to and from a base station 200, an external device, and a server using a mobile communication network, Band cellular communication service. According to an embodiment of the present invention, the cellular communication interface card 122 by the second frequency band may include at least one NIC module using the LTE-Unlicensed frequency band. For example, the LTE-Unlicensed frequency band may be a band of 2.4 GHz or 5 GHz. According to an embodiment of the present invention, at least one NIC module performs cellular communication with at least one of the base station 200, the external device, and the server independently in accordance with the cellular communication standard or protocol of the frequency band supported by the corresponding NIC module . The cellular communication interface card 122 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the terminal 100. [

The wireless LAN interface card 123 according to the second frequency band transmits and receives a radio signal to at least one of the base station 200, the external device, and the server through the wireless LAN connection, Band wireless LAN service. According to an embodiment of the present invention, the wireless LAN interface card 123 according to the second frequency band may include at least one NIC module using the wireless LAN frequency band. For example, the WLAN frequency band may be an unlicensed radio band such as a band of 2.4 GHz or 5 GHz. According to an embodiment of the present invention, at least one NIC module performs wireless communication with at least one of the base station 200, the external device, and the server independently in accordance with a wireless LAN standard or protocol of a frequency band supported by the corresponding NIC module . The wireless LAN interface card 123 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the terminal 100. [

According to an embodiment of the present invention, the processor 110 transmits information on whether or not the wireless LAN communication service of the second frequency band is available through the cellular communication channel of the first frequency band with the base station 200, Information on the period of time. Here, the information on the predetermined period is information set for receiving the downlink data from the base station 200 through the cellular communication channel of the second frequency band.

In addition, according to an embodiment of the present invention, since the base station 200 supports a wireless LAN communication service, the processor 110 can receive a predetermined signal from the base station 200 through a wireless LAN communication channel of a second frequency band And receives the base station coexistence message including information on the period.

In addition, according to an embodiment of the present invention, the processor 110 may be configured to transmit, in response to the received base station coexistence message, The terminal transmits a terminal coexistence message including information on a predetermined period according to a standard or protocol specified in the wireless LAN communication service of the second frequency band.

Also, according to an embodiment of the present invention, the processor 110 receives downlink data from the base station 200 for a predetermined period through a cellular communication channel of a second frequency band.

Next, the memory 130 stores a control program used in the terminal 100 and various data corresponding thereto. The control program may include a predetermined program required for the terminal 100 to perform wireless communication with at least one of the base station 200, the external device, and the server.

Next, the user interface 140 includes various types of input / output means provided in the terminal 100. That is, the user interface 140 can receive user input using various input means, and the processor 110 can control the terminal 100 based on the received user input. In addition, the user interface 140 may perform output based on instructions of the processor 110 using various output means.

Next, the display unit 150 outputs various images on the display screen. The display unit 150 may output various display objects such as a content executed by the processor 110 or a user interface based on a control command of the processor 110. [

12, the base station 200 according to an exemplary embodiment of the present invention may include a processor 210, a communication module 220, and a memory 230. In addition,

First, the processor 210 may execute various commands or programs and may process data within the base station 200. In addition, the processor 210 can control the entire operation including each unit of the base station 200, and can control data transmission / reception between the units.

Next, the communication module 220 may be an integrated module for performing mobile communication using a mobile communication network and wireless LAN connection using a wireless LAN, such as the communication module 120 of the terminal 100 described above. To this end, the communication module 120 may include a plurality of network interface cards, such as the cellular communication interface cards 221 and 222 and the wireless LAN interface card 223, either internally or externally. 12, the communication module 220 is shown as an integrated integration module, but each network interface card may be independently arranged according to the circuit configuration or use, unlike in FIG.

The cellular communication interface card 221 according to the first frequency band transmits and receives a radio signal to at least one of the terminal 100, the external device, and the server using the mobile communication network, And provides cellular communication service by one frequency band. Here, the wireless signal may include various types of data or information such as a voice call signal, a video call signal, or a text / multimedia message.

According to an embodiment of the present invention, the cellular communication interface card 221 by the first frequency band may include at least one NIC module using the LTE-Licensed frequency band. According to an embodiment of the present invention, the at least one NIC module can perform cellular communication with at least one of the terminal 100, the external device, and the server independently according to the cellular communication standard or protocol of the frequency band supported by the corresponding NIC module. Can be performed. The cellular communication interface card 221 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the base station 200.

The cellular communication interface card 222 according to the second frequency band transmits and receives a radio signal to at least one of the terminal 100, the external device, and the server using the mobile communication network, And provides a cellular communication service by two frequency bands. According to an embodiment of the present invention, the cellular communication interface card 222 by the second frequency band may include at least one NIC module using the LTE-Unlicensed frequency band. For example, the LTE-Unlicensed frequency band may be a band of 2.4 GHz or 5 GHz. According to an embodiment of the present invention, the at least one NIC module can perform cellular communication with at least one of the terminal 100, the external device, and the server independently according to the cellular communication standard or protocol of the frequency band supported by the corresponding NIC module. Can be performed. The cellular communication interface card 222 may operate only one NIC module at a time or may operate a plurality of NIC modules at the same time according to the performance and requirements of the base station 200. [

The wireless LAN interface card 223 according to the second frequency band transmits and receives a wireless signal to at least one of the terminal 100, the external device, and the server through the wireless LAN connection, 2 frequency band. According to an embodiment of the present invention, the wireless LAN interface card 223 according to the second frequency band may include at least one NIC module using the wireless LAN frequency band. For example, the WLAN frequency band may be an unlicensed radio band such as a band of 2.4 GHz or 5 GHz. According to an embodiment of the present invention, at least one NIC module independently communicates with at least one of the terminal 100, the external device, and the server in accordance with a wireless LAN standard or protocol of a frequency band supported by the corresponding NIC module Can be performed. The wireless LAN interface card 223 can operate only one NIC module at a time or operate a plurality of NIC modules at the same time according to the performance and requirements of the base station 200. [

According to an embodiment of the present invention, the processor 210 transmits information on whether or not the wireless LAN communication service of the second frequency band is available through the cellular communication channel of the first frequency band with the terminal 100, Information on the period of time. Here, the information on the predetermined period is information set for transmitting the downlink data to the terminal 100 through the cellular communication channel of the second frequency band.

In addition, according to an embodiment of the present invention, the processor 210 may be a peripheral terminal capable of communicating with the base station 200 through the terminal 100 and the wireless LAN communication service of the second frequency band, And transmits the base station coexistence message including information on a predetermined period according to a standard or protocol defined in the wireless LAN communication service to the terminal 100 for a predetermined period on the cellular communication channel of the second frequency band, .

In addition, according to an embodiment of the present invention, since the terminal 100 supports the wireless LAN communication service, the processor 210 transmits the base station coexistence message Lt; RTI ID = 0.0 > coexistence < / RTI > Here, the terminal coexistence message includes information on a predetermined period.

The terminal 100 and the base station 200 shown in FIG. 12 are block diagrams according to an embodiment of the present invention. Blocks that are separately displayed are logically distinguished from elements of a device. Thus, the elements of the device described above can be mounted as one chip or as a plurality of chips depending on the design of the device. In addition, in the embodiment of the present invention, some components of the terminal 100, such as the user interface 140 and the display unit 150, may be optionally provided in the terminal 100. In addition, in the embodiment of the present invention, the user interface 140, the display unit 150, and the like may be additionally provided to the base station 200 as needed.

A general uplink transmission is a grant-based (GB) transmission in which a grant is received from a base station and the UE sets up to perform transmission on the corresponding resource according to the corresponding scheduling information. In GB transmission, the base station constructs downlink control information (e.g., DCI) for UL grant for uplink transmission, and transmits the downlink control channel. The UE can transmit the TB mapped to the HARQ process ID according to the HARQ process ID of the UL grant through the time-frequency resource informed by the UL grant. The UE manages the HARQ retransmission based on the UL grant having the same HARQ process ID, and when the new data indicator (NDI) indicated in the UL grant from the base station is compared with the NDI in the previously received UL grant, It is determined that the previous TB has been successfully received, and if not, the retransmission procedure for the TB can be performed.

13 is a diagram illustrating an uplink grant-free (GF) transmission scheme. Referring to FIG. 13, if there is data to be transmitted by the user, the uplink GF transmission does not receive the grant from the base station, but can transmit the uplink GF according to preset configuration information or predefined time-frequency resources according to the configuration information. At this time, the time-frequency resources may be configured differently for each UE. The demodulation reference signal (DM-RS) used by the UE in GF transmission can be configured differently according to the UE. Therefore, the UE can transmit the DM-RS and the data configured for itself in the time-frequency resource configured in the uplink grant-free transmission. In order to increase the reliability of the uplink grant-free transmission, the base station can configure the repeated transmission to the mobile station. When the K-times repetitive transmission is configured, the UE can repeatedly transmit K times. When the UE receives an ACK for the uplink GF transmission, the iterative transmission can be terminated. When the base station receives the uplink GF transmission, it finds which terminal transmitted the GF resource through the time-frequency resource and the DMRS, but may fail to receive the data. In this case, the UE can transmit a grant for uplink retransmission to the UE. The UE can suspend the grant-free transmission of the corresponding TB by receiving the grant for the uplink retransmission and perform grant-based (GB) retransmission.

When a base station requests a GF transmission with a GB retransmission, the HARQ process ID (or HARQ process number) of the corresponding TB should be allocated to the UE. The HARQ process ID of the TB transmitted to the GF includes a symbol index, a slot index, a surfef frame index, an index mapped to a time-frequency resource, or indexes matched to a DM-RS, Can be determined in combination. However, since the HARQ process ID may already be used for another TB, the HARQ process ID may be repeatedly used. The present invention provides a method for allocating a HARQ process ID to a TB that performs GF transmission and a terminal operation when an allocated HARQ process ID collides.

In one embodiment of the present invention, the HARQ process IDs of the TBs transmitted in the uplink GF among all the HARQ process IDs can be separately set. The set HARQ process IDs can be used only when retransmitting a TB transmitted in GF to GB. To this end, the HARQ process ID of the GF transmission includes a symbol index, a slot index, a surfef frame index, an index mapped to a time-frequency resource, or a combination of indexes matched to a DM-RS, And may be mapped to one of the set HARQ process IDs.

In one embodiment of the present invention, the Node B and the UE can determine the HARQ process ID, which can be used for GB retransmission of the TB transmitted in the GF among all the HARQ process IDs, based on the HARQ process ID usage level. For example, the available HARQ process IDs among all the HARQ process IDs may be HARQ process IDs that the UE has never used. For example, the available HARQ process ID among the HARQ process IDs may be an HARQ process ID that the UE has never used for a certain period of time. The HARQ process IDs determined to be usable may be used as a HARQ process ID when retransmitting TBs transmitted in GF to GB. To this end, the HARQ process ID of the GF transmission includes a symbol index, a slot index, a surfef frame index, an index mapped to a time-frequency resource, or a combination of indexes matched to a DM-RS, And may be mapped to one of the HARQ process IDs determined to be usable.

In one embodiment of the present invention, information may be included to inform the UL grant whether the retransmission of the TB transmitted in the GB or the retransmission of the TB transmitted in the GF. When the UL grant instructs the retransmission of the TB transmitted in GB, the UE can transmit the TB mapped to the HARQ process ID of the UL grant according to the UL grant among the TBs transmitted in the GB. When retransmission of a TB transmitted from an UL grant to a GF is instructed, the UE can transmit a TB that is mapped to the HARQ process ID of the UL grant according to the UL grant among the TBs transmitted to the GF. In one embodiment, a 1-bit indicator may be present to indicate whether the retransmission of the TB transmitted in the UL grant to the GB or the retransmission of the TB transmitted to the GF is performed. In another embodiment of the present invention, downlink control information (e.g., DCI) including the UL grant is transmitted to inform the retransmission of the TB transmitted from the UL grant to the GB or the retransmission of the TB transmitted to the GF It is possible to set the downlink control channel for reception to be scrambled by the RNTI different from the RNTI for the GB transmission so that the mobile station can distinguish the downlink control channel.

In one embodiment of the present invention, information on whether a UL grant is a retransmission of a TB transmitted in GB or a retransmission of a TB transmitted in a GF includes mapping a downlink control channel including UL grant to a different search space The UE can be determined according to the search space in which the downlink control channel transmitted including the UL grant is detected. For example, a search space (search space: a set of PDCCH candidates to be blind decoded) is defined, and a UL grant having the same HARQ process ID as the HARQ process ID of the TB transmitted from the search space to the GF is transmitted , The terminal may always assume that the corresponding UL grant requests retransmission of the TB transmitted to the GF. On the contrary, if the UL grant having the same HARQ process ID as the HARQ process ID of the TB transmitted to the GF in the search space excluding the specific search space is transmitted, it can be assumed that the corresponding UL grant always requests retransmission of the TB transmitted in GB have. Preferably, the particular search space may be a common search space. Preferably, the specific search space may be configured for the UE with specific PDCCH candidates.

Referring to FIG. 14, in an embodiment of the present invention, after a UE performs a GF transmission, a UL grant including a HARQ process ID determined by a GF transmission is received for a predetermined monitoring period (for example, N slot) , It can be assumed that the GF transmission is GB retransmission. Therefore, the UE can transmit the retransmission of the GF transmission according to the UL grant. In a preferred embodiment of the present invention, the monitoring period may be a fixed value that the base station configures to the terminal. In another preferred embodiment, the monitoring period may be determined by the UE according to the latency requirement of the TB transmitted by the UE in the GF transmission mode. Referring to FIG. 15, if the HARQ process ID is an HARQ process ID that is not used for a predetermined time, UL grant including the HARQ process ID, i.e., downlink control information (e.g., DCI, Downlink control the new data indicator (NDI) of the information may be set to a particular value (e.g., 0). If the HARQ process ID is a HARQ process ID used before a predetermined time, an UL grant including a HARQ process ID, i.e., an NDI of a specific information field (e.g., DCI) in the DL control information configuring the UL grant, can be set to toggled values. Referring to FIG. 15- (b), if the NDI is not toggled, the terminal transmits the TB of the previous GB transmission allocated to the HARQ process ID according to the UL grant. Referring to FIG. 15- (a) If the NDI is toggled, the TB of the GF transmission assigned to the HARQ process ID can be transmitted according to the UL grant. Within the monitoring period in which the UE monitors the retransmission of the GF, an interpretation different from a normal terminal interpretation can be made for the NDI transmitted through the UL grant from the base station. In the case of normal UL grant-based transmission, when the NDI is toggled in the corresponding UL grant, the grant-based transmission of the previous transmission having the corresponding HARQ process ID succeeds and is considered as a new HARQ process ID, , If the UE receives an UL grant having the same HARQ process ID in which the NDI is toggled during the monitoring period, the TB of the previous GB transmission assigned to the HARQ process ID can be set to assume that the transmission fails .

Referring to FIG. 16, in an exemplary embodiment of the present invention, after a UE performs GF transmission, downlink control information including an UL grant by additionally using another RNTI during a monitoring period (e.g., N slot) (E. G., DCI). ≪ / RTI > When the UE receives downlink control information (e.g., DCI) including an UL grant in the other RNTI, the UE can retransmit the GF transmission according to the UL grant. If the HARQ process ID is included in the received downlink control information, the TB transmitted to the GF may be mapped to the HARQ process ID, the TB of the GB transmission mapped to the HARQ process ID may be discarded at the current time, The TB corresponding to the HARQ process ID may be set to flush the buffer or delayed for transmission at the next opportunity.

Referring to FIG. 17, when a plurality of GF based transmissions occur, if there is an HARQ process ID in downlink control information (e.g., DCI) including UL grant in the other RNTI, mapping to the HARQ process ID Lt; RTI ID = 0.0 > UL < / RTI > grant. The terminal desirably discards the GB transmission mapped to its HARQ process ID (assuming that the transmission has failed), or assumes that the transmission succeeded, and the terminal can assume that the HARQ process ID indicates the GF transmission. When multiple GF based transmissions occur, it is possible to have multiple monitoring period configurations so that each GF transmission has a separate monitoring period.

Referring to FIG. 18, a UE performs downlink control information including an UL grant (e.g., C-RNTI) during a monitoring period (e.g., N slot) If the HARQ process ID mapped to the UL grant is equal to the HARQ process ID of the GF transmission when receiving the DCI, the UE retransmits the TB of the GB transmission mapped to the HARQ process ID with the UL grant, The TB of the GF mapped to the HARQ process ID is determined to have failed to transmit, and the UE may transmit the GF transmission method again. Also, the monitoring for the GF transmission having the same HARQ process ID as the corresponding HARQ process ID can be stopped.

Preferably, the other RNTI may be an RNTI for GF transmission. Preferably, the different RNTI includes at least one of a symbol index, a slot index, a subframe index, an index mapped to a time-frequency resource, an index matched with a DM-RS, -RNTI), an RNTI for a GF transmission, or a combination of parts thereof.

Referring to FIG. 19, in an embodiment of the present invention, when a HARQ-ACK for a GF transmission is set to be transmitted to a mobile station by a base station and a corresponding HARQ-ACK is received, It can be interpreted differently. There are various methods for transmitting a HARQ-ACK for GF transmission to a mobile station, and there is a method for receiving through a group-common PDCCH or a method for receiving over a common PDCCH for GF transmission, Alternatively, there may be a method of receiving a GF transmission through a UE-specific PDCCH to a configured UE, or a method of setting a separate channel in the form of a CCE configuration and transmitting through a separate channel, and other methods may be considered Preferably, the UE receives a NACK for GF transmission and receives an UL grant including an HARQ process ID corresponding to the GF transmission, the UE interprets the retransmission as a GF transmission and transmits the GF transmission Can be retransmitted. Preferably, if ACK / NACK for the GF transmission is not received, the terminal can interpret it as retransmission for the corresponding GB transmission if it receives an UL grant including the HARQ process ID corresponding to the GF transmission. At this time, it is determined that the GF transmission has failed and can be transmitted again to the GF transmission method.

Referring to FIG. 20, in an embodiment of the present invention, a HARQ process ID to be set by a UE may be transmitted together with a GF transmission. More specifically, the UE can perform GF transmission using the DMRS corresponding to the HARQ process ID to be set at the GF transmission. The base station can receive the HARQ process ID to be set up by the terminal by receiving the DMRS, and can request the terminal to retransmit the GB through the received HARQ process ID. Alternatively, the UE may multiplex the HARQ process ID to be set in the GF transmission with the uplink data. That is, when the UE performs the GF transmission, it can transmit the DM-RS, data, and the HARQ process ID as the configured time-frequency resources. The base station confirms which terminal is transmitting the GF through the DM-RS. If the base station fails to receive the data, it can request the terminal to retransmit the GB through the received HARQ process ID. Alternatively, the UE may transmit the HARQ process ID to be set upon transmission of the GF through another channel. For example, if there is an HARQ process ID to be set as the uplink transmission, the UE may transmit the ID to the BS through the PUSCH or the PUCCH. If the BS knows that a particular UE has transmitted a GF and fails to receive data, if there are other channels allocated to the UE, the BS may request the GB retransmission using the HARQ process ID transmitted through the channel.

Referring to FIG. 21, when there is a TB of a GB transmission and a TB of a GF transmission corresponding to an HARQ process ID of an UL grant to be transmitted in a base station from a mobile station, Can be selected and transmitted. For example, if the TB of the GF transmission violates the latency condition, the TB of the GB transmission is transmitted. If the TB of the GF transmission does not violate the latency condition, the TB of the GF transmission and the TB of the GB transmission, Can be transmitted. If the terminal does not inform the terminal of the selected one, the base station can perform all detection for the case that the terminal can select. In order to reduce the complexity at the base station, the UE can transmit information for informing the TB of a transmission to the base station. Preferably, information for notifying the base station of the transmission of the TB of the transmission may be transmitted on the PUCCH. The PUCCH may be multiplexed with the PUSCH, and may be piggybacked to the PUSCH if the PUSCH resource is set in the terminal. Preferably, the information for indicating the transmission of the TB of the transmission to the base station may be phase shifted by the DMRS for transmitting the PUSCH. When the UE performs retransmission of the TB of the GB transmission, it transmits the determined PUSCH DMRS and when the UE retransmits the TB of the GF transmission, it can phase shift the determined PUSCH DMRS. The base station can determine whether the terminal retransmits the TB transmitted to the GF or the TB transmitted through the GB by detecting the phase shift value of the PUSCH DMRS.

In one embodiment of the present invention, when a base station determines that a UE has performed a GF transmission but fails to receive data, it determines that the UE has transmitted a scheduling request (SR) signal and transmits the SR signal to an upper layer . The MS can expect the BS to operate in the same manner as when the SR signal is transmitted.

While the methods and systems of the present invention have been described in connection with specific embodiments, some or all of those elements or operations may be implemented using a computer system having a general purpose hardware architecture.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

Claims (1)

Method and apparatus for transmitting and receiving data between a terminal and a base station

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