Terminal, base station and method thereof

Abstract

Disclosed are a terminal, a base station, and a method thereof in a wireless communication system. The method, performed by the terminal, includes: receiving information configuring multiple search spaces of the terminal from the base station; identifying overlap between a common search space (CSS) and a user equipment (UE)-specific search space (USS); if the CSS and USS overlap, receiving downlink control information based only on the CSS by monitoring a physical downlink control channel (PDCCH); and sending a physical uplink shared channel (PUSCH) transmission to the base station based on the downlink control information received on the PDCCH corresponding to the CSS.

Description

[0001] This application is a divisional application of an invention patent application with an application date (international application date) of October 25, 2017, application number 201780075468.9, and invention name “Method and device for decoding downlink control signals in a wireless cellular communication system”. Technical Field

[0002] The present invention relates to a wireless communication system and a method and apparatus for decoding a downlink control signal. Specifically, the present invention relates to a method for a terminal with a delay reduction mode to detect a downlink control signal and determine the feedback timing of a HARQ-ACK corresponding to the downlink signal when the delay reduction mode of the terminal is configured. Background Art

[0003] In order to meet the growing demand for wireless data services since the commercialization of the 4th generation (4G) communication system, the development focus has fallen on the 5th generation (5G) or pre-5G (pre-5G) communication system. Therefore, the 5G or pre-5G communication system is called a super 4G network communication system or a late long-term evolution (LTE) system. Consideration is being given to implementing the 5G communication system in the millimeter wave (mmW) band (e.g., the 60 GHz band) to achieve higher data rates. In order to increase the propagation distance by reducing the propagation loss in the 5G communication system, various technologies are being discussed, such as beamforming, massive multiple input multiple output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antennas. In addition, in order to enhance the network performance of the 5G communication system, various technologies are being developed, such as evolved small cells, advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving networks, collaborative communications, coordinated multipoint (CoMP), and interference cancellation. Additionally, ongoing research includes the use of FQAM {hybrid frequency shift keying (FSK) and quadrature amplitude modulation (QAM)} and sliding window superposition coding (SWSC) as advanced coded modulation (ACM), filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA).

[0004] At the same time, the Internet is evolving from a human-centric communication network where humans generate and consume information to the Internet of Things (IoT), where distributed objects or components exchange and process information. The combination of cloud-based big data processing technology and the IoT has given rise to the Internet of Everything (IoE) technology. To ensure the sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology required to realize the IoT, recent research has focused on sensor networks, machine-to-machine (M2M), and machine-type communication (MTC) technologies. In the IoT environment, it is possible to provide intelligent Internet technology that can collect and analyze data generated by connected objects, creating new value for human life. The IoT can be applied to various fields such as smart homes, smart buildings, smart cities, smart cars or connected vehicles, smart grids, healthcare, smart appliances, and smart medical services through the integration of traditional information technology (IT) and various industries.

[0005] Therefore, there are various attempts to apply IoT to 5G communication systems. For example, sensor networks, M2M, and MTC technologies are implemented with the help of 5G communication technologies such as beamforming, MIMO, and array antennas. The application of cloud RAN as a big data processing technology is an example of the convergence between 5G and IoT technologies.

[0006] In order for such a communication system to provide multiple services to users, a method and apparatus are needed that can process services with different characteristics in the same time period without compromising the service characteristics.

[0007] In a conventional LTE system, 3 ms after receiving downlink data, HARQ ACK or NACK feedback indicating whether the downlink data transmission was successful is transmitted to the base station in the uplink. For example, the HARQ ACK / NACK corresponding to the physical downlink shared channel (PDSCH) transmitted from the base station to the terminal at subframe n is transmitted to the base station at subframe n+4 via the physical uplink control channel (PUCCH) or the physical uplink shared channel (PUSCH). In an FDD LTE system in which the base station transmits downlink control information (DCI) including information about the uplink resources allocated to the terminal and allows the terminal to request retransmission via the physical hybrid ARQ indicator channel (PHICH), if the terminal receives an uplink grant for scheduling uplink data transmission at subframe n, it transmits uplink data at subframe n+4. That is, PUSCH transmission is performed at subframe n+4. Unlike the above-described example for the FDD LTE system, HARQ ACK / NACK transmission timing or PUSCH transmission timing varies according to an uplink-downlink subframe configuration conforming to a predetermined rule in the TDD LTE system. Summary of the Invention

[0008]

Technical Issues

[0009] In FDD or TDD LTE systems, the HARQ ACK / NACK transmission timing or PUSCH transmission timing is predetermined to ensure 3ms, which is sufficient for the base station or terminal to process the signal. If the signal processing time of the LTE base station and terminal is reduced to 1 or 2ms, the data transmission delay can also be reduced.

[0010] When a terminal with delay reduction mode transmission is configured to operate in delay reduction mode, the transmission timing of HARQ-ACK corresponding to downlink data or uplink data corresponding to uplink data authorization may vary according to the search space in which the DCI is detected. For example, for the case where the DCI is detected in the common search space, the uplink transmission timing may fall in subframe n+4, and for the case where the DCI is detected in the terminal-specific search space, the uplink transmission timing may fall in subframe n+4. However, for a specific terminal, it may happen that the search space may be both a common search space and a terminal-specific search space; for this case, the operation of the terminal and the base station needs to be defined. The present invention provides a signal transmission / reception method and apparatus that can allow a terminal to decode a downlink control signal, and a base station and a terminal to transmit a signal based on this.

[0011] [Solution to the problem]

[0012] According to one aspect of the present invention, a method for a terminal in a wireless communication system includes: receiving a control signal for scheduling uplink transmission from a base station, determining whether a timing for transmitting an uplink signal is a first timing or a second timing based on a search space in which the control signal is detected, the second timing being earlier than the first timing, and transmitting the uplink signal to the base station with the first timing or the second timing.

[0013] According to another aspect of the present invention, a terminal in a wireless communication system includes: a transceiver configured to transmit and receive signals; and a controller configured to control to receive a control signal for scheduling uplink transmission from a base station, determine whether the timing for transmitting the uplink signal is a first timing or a second timing based on a search space in which the control signal is detected, the second timing being earlier than the first timing, and transmit the uplink signal to the base station at the first timing or the second timing.

[0014] According to another aspect of the present invention, a method of a base station in a wireless communication system includes: transmitting a control signal for scheduling uplink transmission to a terminal, and receiving an uplink signal from the terminal with both a first timing and a second timing based on a search space to which the control signal is mapped, wherein the second timing is earlier than the first timing.

[0015] According to another embodiment of the present invention, a base station in a wireless communication system includes: a transceiver configured to transmit and receive signals; and a controller configured to control to transmit a control signal for scheduling uplink transmission to a terminal, and to receive an uplink signal from the terminal at both a first timing and a second timing based on a search space to which the control signal is mapped, wherein the second timing is earlier than the first timing.

[0016] According to another embodiment of the present invention, a method performed by a terminal in a wireless communication system includes: receiving information configuring multiple search spaces of the terminal from a base station; monitoring a physical downlink control channel PDCCH; determining to monitor the PDCCH in the CSS when monitoring the PDCCH in an overlapping area where a common search space CSS and a user equipment UE-specific search space USS overlap; and based on the downlink control information received on the PDCCH corresponding to the CSS, in the transmission timing, the user equipment UE-specific search space sends a physical uplink shared channel PUSCH to the base station.

[0017] According to another embodiment of the present invention, a method performed by a base station in a wireless communication system includes: sending information for configuring multiple search spaces of the terminal to a terminal; sending downlink control information on a physical downlink control channel PDCCH in an overlapping area where a common search space CSS and a USS overlap; and receiving a physical uplink shared channel PUSCH from the terminal in transmission timing based on the downlink control information sent on the PDCCH corresponding to the CSS, wherein, in a case where the downlink control information is sent in the overlapping area, the downlink control information is decoded in the CSS.

[0018] According to another embodiment of the present invention, a terminal in a wireless communication system includes: a transceiver configured to send and receive signals; and a controller configured to: receive information configuring multiple search spaces of the terminal from a base station, monitor a physical downlink control channel PDCCH, and in the case of monitoring the PDCCH in an overlapping area where a common search space CSS and a user equipment UE-specific search space USS overlap, determine to monitor the PDCCH in the CSS, and based on the downlink control information received on the PDCCH corresponding to the CSS, send a physical uplink shared channel PUSCH to the base station in transmission timing.

[0019] According to another embodiment of the present invention, a base station in a wireless communication system includes: a transceiver configured to send and receive signals; and a controller configured to: send information for configuring multiple search spaces of the terminal to a terminal, send downlink control information on a physical downlink control channel PDCCH in a case where a common search space CSS and a user equipment UE-specific search space USS overlap, and receive a physical uplink shared channel PUSCH from the terminal in transmission timing based on the downlink control information sent on the PDCCH corresponding to the CSS, wherein, in a case where downlink control information is sent in an overlapping area, the downlink control information is decoded in the CSS.

[0020] [Beneficial effects of the invention]

[0021] The present invention is advantageous in improving resource utilization efficiency by providing a method for decoding a control signal in a delay reduction mode and transmitting a signal between a base station and a terminal based on the decoding result. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 FIG2 is a diagram showing basic time-frequency resources configured for transmitting downlink data or control channels in an LTE or LTE-A system.

[0023] Figure 2 is a block diagram showing a basic time-frequency resource structure for transmitting uplink data or control channels in an LTE or LTE-A system;

[0024] Figure 3 is a diagram illustrating frequency-time resources allocated for transmitting data for eMBB, URLLC, and mMTC services in a communication system;

[0025] Figure 4 is another diagram illustrating frequency-time resources allocated for transmitting data for eMBB, URLLC, and mMTC services in a communication system;

[0026] Figure 5 is a diagram illustrating a process of dividing a transport block into a plurality of code blocks and adding a CRC to the code blocks;

[0027] Figure 6 is a flow chart showing an uplink transmission method of a terminal;

[0028] Figure 7 A flowchart illustrating an operating method of a base station according to embodiment 1 is shown;

[0029] Figure 8 A flowchart showing a method for operating a terminal according to embodiment 1 is shown;

[0030] Figure 9 A flowchart illustrating an operating method of a base station according to embodiment 2 is shown;

[0031] Figure 10 A flowchart showing a method for operating a terminal according to Embodiment 2 is shown;

[0032] Figure 11 is a flowchart showing the operations of a base station and a terminal according to Embodiment 3;

[0033] Figure 12 A flowchart showing operations of a base station and a terminal according to Embodiment 4 is shown;

[0034] Figure 13 is a flowchart showing the operations of the base station and the terminal according to embodiment 4-1;

[0035] Figure 14 is a flowchart showing the operation of the base station according to Embodiment 5;

[0036] Figure 15 is a block diagram showing a configuration of a terminal according to an embodiment of the present invention; and

[0037] Figure 16 is a block diagram showing a configuration of a base station according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] Detailed description of technical specifications well known in the art and not directly related to the present invention may be omitted to avoid obscuring the subject matter of the present invention. This is intended to omit unnecessary descriptions in order to clearly illustrate the subject matter of the present invention.

[0039] For the same reason, some elements are exaggerated, omitted or simplified in the drawings, and in practice, elements may have sizes and / or shapes different from those shown in the drawings. In the entire drawings, identical or equivalent parts are represented by the same reference numerals.

[0040] The advantages and features of the present invention and the methods of achieving them may be more readily understood by reference to the following detailed description of exemplary embodiments and the accompanying drawings. However, the present invention may be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein; rather, these exemplary embodiments are provided to make this disclosure thorough and complete and to fully convey the concepts of the present invention to those skilled in the art, and the present invention will be limited only by the appended claims. Throughout the specification, like reference numerals refer to like elements.

[0041] It will be understood that each block of the flowchart and / or block diagram, as well as combinations of blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that the instructions executed by the processor of the computer or other programmable data processing device create means for implementing the functions / behaviors specified in the flowchart and / or block diagram. These computer program instructions can also be stored in a non-transitory computer-readable memory, which can instruct the computer or other programmable data processing device to function in a specific manner, such that the instructions stored in the non-transitory computer-readable memory generate an article-embedded instruction means for implementing the functions / behaviors specified in the flowchart and / or block diagram. The computer program instructions can also be loaded onto a computer or other programmable data processing device to cause a series of operational steps for generating a computer-implemented process to be executed on the computer or other programmable device, such that the instructions executed on the computer or other programmable device provide steps for implementing the functions / actions specified in the flowchart and / or block diagram.

[0042] In addition, each block diagram may show a module, segment, or portion of code that includes at least one or more executable instructions for performing a specific logical function. In addition, it should be noted that the functions of the blocks can be performed in a different order in several modifications. For example, two consecutive blocks can be executed substantially simultaneously, or they can be executed in reverse order based on their functions.

[0043] According to various embodiments of the present invention, the term "module" means, but is not limited to, a software or hardware component that performs certain tasks, such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC). A module can advantageously be configured to reside on an addressable storage medium and to be configured to execute on one or more processors. Thus, as an example, a module can include components, processes, functions, properties, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables such as software components, object-oriented software components, class components, and task components. The functions of components and modules can be combined into fewer components and modules, or further divided into more components and modules. In addition, components and modules can be implemented so that they perform the functions of one or more CPUs in a device or secure multimedia card.

[0044] Mobile communication systems have evolved into high-speed, high-quality packet data communication systems capable of providing data and multimedia services in addition to early voice-oriented services (such as High Speed Packet Access (HSPA), LTE (or Evolved Universal Terrestrial Radio Access (E-UTRA)), and LTE-Advanced (LTE-A) defined by the 3rd Generation Partnership Project (3GPP), High Rate Packet Data (HRPD) defined by the 3rd Generation Partnership Project-2 (3GPP2), Ultra Mobile Broadband (UMB), and 802.16e defined by the IEEE). Meanwhile, 5G wireless communication systems are undergoing 5G or NR standardization.

[0045] Such a wireless communication system including a 5G system can provide services to the terminal that fall into at least one of the following service categories: enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable and low-latency communication (URLLC). These services can be provided to the terminal simultaneously over a period of time. eMBB is intended to provide high throughput and high data rate, mMTC provides low power consumption and multi-terminal access, and URLLC provides high reliability and low latency; however, they are not limited to the embodiments of the present invention. These three types of services relate to the main scenarios in LTE or beyond systems including 5G / NR systems. Embodiments of the present invention relate to methods and devices for supporting the coexistence of eMBB and URLLC services or mMTC and URLLC services.

[0046] In the case where URLLC service data is to be transmitted in a transmission time interval (TTI) in which the base station has scheduled eMBB service data for a certain terminal, the base station may transmit the URLLC service data in part of the frequency band in which the eMBB service data transmission is scheduled. The terminal scheduled for the eMBB service and the terminal scheduled for the URLLC service may be the same as or different from each other. In this case, part of the scheduled eMBB data is not transmitted, so that the eMBB data may be damaged. Therefore, there is a need for a method for a terminal scheduled for the eMBB service or a terminal scheduled for the URLLC service to properly receive and process a signal carrying service data. According to an embodiment of the present invention, when eMBB service-related information and URLLC service-related information are scheduled simultaneously in part or the entire frequency band, when mMTC service-related information and URLLC service-related information are scheduled simultaneously in part or the entire frequency band, or when eMBB service-related information, URLLC service-related information and mMTC service-related information are scheduled simultaneously, a method for promoting the coexistence of different types of services may make it possible to transmit service-specific information.

[0047] Exemplary embodiments of the present invention are described in detail with reference to the accompanying drawings. Detailed descriptions of well-known functions and structures included herein may be omitted to avoid obscuring the subject matter of the present invention. In addition, the following terms are defined with regard to the functions in the present invention, and they may vary depending on the user's or operator's intention, usage, etc. Therefore, they should be defined based on the overall content of this specification. In the following description, the term "base station (BS)" is used to indicate an entity for allocating resources to a terminal, and examples include gNodeB (gNB), evolved NodeB (eNB), NodeB, radio access unit, base station controller, and a predetermined network node. Examples of terminals include user equipment (UE), mobile station (MS), cellular phone, smartphone, computer, and multimedia system with communication function. In the following description, the term "downlink (DL)" refers to the radio transmission path from the base station to the terminal, and the term "uplink (UL)" refers to the radio transmission path from the terminal to the base station. Although the description by example is for LTE or LTE-A systems, the present invention is applicable to other communication systems with similar technical backgrounds and channel formats. For example, the present invention is applicable to 5G mobile communication technology (5G New Radio (NR)) being developed after LTE-A. Those skilled in the art will appreciate that the present invention can be applied to other communication systems even with slight modifications without departing from the spirit and scope of the present invention.

[0048] As one of the representative broadband wireless communication systems, the LTE system uses orthogonal frequency division multiplexing (OFDM) in the downlink and single-carrier frequency division multiple access (SC-FDMA) in the uplink. The term "uplink" refers to the radio transmission path from the terminal (or UE or MS) to the base station (gNB), and the term "downlink" refers to the radio transmission path from the base station to the terminal. This multiple access scheme is characterized by allocating time-frequency resources for transmitting user-specific data and control information without mutual overlap, that is, maintaining orthogonality, so as to distinguish between user-specific data and control information.

[0049] When a decoding failure occurs during initial data transmission, the LTE system uses a hybrid automatic repeat request (HARQ) scheme for physical layer retransmission. The HARQ scheme is designed to operate as follows: when a receiver fails to decode data, it sends a negative acknowledgement (NACK) indicating the decoding failure to the transmitter, prompting the transmitter to retransmit the corresponding data on the physical layer. The receiver combines the retransmitted data with the data that failed to be decoded to improve data reception performance. The HARQ scheme is also designed to operate as follows: when the receiver successfully decodes the data, it sends an acknowledgement (ACK) indicating the successful decoding to the transmitter, prompting the transmitter to transmit new data.

[0050] Figure 1FIG2 is a diagram showing basic time-frequency resources configured for transmitting downlink data or a control channel in an LTE system.

[0051] exist Figure 1 In the figure, the horizontal axis represents time and the vertical axis represents frequency. The minimum transmission unit in the time domain is the OFDM symbol, and N symb OFDM symbols 102 form a time slot 106, and 2 time slots form a subframe 105. Each time slot spans 0.5 ms, and each subframe spans 1.0 ms. A radio frame 114 is a time unit consisting of 10 subframes. In the frequency domain, the smallest transmission unit is a subcarrier, and the total system transmission bandwidth is N BW The number of subcarriers 104 may vary.

[0052] In the time-frequency resource structure, the basic resource unit is a resource element (RE) indicated by an OFDM symbol index and a subcarrier index. A resource block (RB) (or a physical resource block (PRB) 108) consists of N symb consecutive OFDM symbols 102 and N in the frequency domain RB 100. That is, one RB 108 is defined by N consecutive subcarriers 110. symb x N RB 112 REs. Generally, RB is the smallest data transmission unit; in LTE system, N symb =7, N RB =12, N BW and N RB Proportional to the system transmission bandwidth. The data rate increases in proportion to the number of RBs scheduled for the terminal. For the LTE system, 6 transmission bandwidths are defined. In the case of a frequency division duplex (FDD) system in which the downlink and uplink are separated in frequency, the downlink transmission bandwidth and the uplink transmission bandwidth may be different from each other. Compared with the system transmission bandwidth, the channel bandwidth represents the RF bandwidth. Table 1 shows the relationship between the system transmission bandwidth and the channel bandwidth defined in the LTE standard. For example, an LTE system with a 10 MHz channel bandwidth uses a transmission bandwidth of 50 RBs.

[0053] [Table 1]

[0054]

[0055] At the beginning of a subframe, downlink control information is transmitted using N OFDM symbols. Typically, N = {1, 2, 3}. Therefore, the value of N varies at each subframe depending on the amount of control information to be transmitted. The control information includes a control channel transmission period indicator, which indicates the number of OFDM symbols used to transmit control information, scheduling information for downlink or uplink data transmission, and HARQ ACK / NACK signals.

[0056] In the LTE system, downlink control information (DCI) is used to transmit downlink or uplink data scheduling information from the base station to the terminal. DCI is classified into different DCI formats according to its purpose, such as a format indicating a UL grant for UL data scheduling or a DL grant for DL data scheduling, indicating the use of small-sized control information, indicating whether spatial multiplexing based on multiple antennas is applied, and indicating the use of power control. For example, DCI format 1 for DL grant is configured to include at least the following information.

[0057] - Resource Allocation Type 0 / 1 Flag: The resource allocation type 0 / 1 flag indicates whether the resource allocation scheme is type 0 or type 1. Type 0 allocates resources in units of resource block groups (RBGs) by applying a bitmap scheme. In the LTE system, the basic unit of scheduling can be a resource block (RB) represented by time-frequency domain resources, and an RBG can include multiple RBs and can be the basic unit of scheduling in the type 0 scheme. Type 1 is used to allocate specific RBs in an RBG.

[0058] - Resource Block Allocation: Resource block allocation indicates RBs allocated for data transmission. Resources can be determined according to system bandwidth and resource allocation scheme.

[0059] - Modulation and Coding Scheme (MCS): MCS indicates the modulation scheme used for data transmission and the size of the transport block (TB) to be transmitted.

[0060] -HARQ process number: The HARQ process number indicates the HARQ process number.

[0061] - New data indicator: The new data indicator indicates whether the HARQ transmission is an initial transmission or a retransmission.

[0062] - Redundancy Version (RV): Redundancy version indicates the redundancy version of HARQ.

[0063] - TPC command for PUCCH: A Transmission Power Control (TPC) command for a Physical Uplink Control Channel (PUCCH) indicates a power control command for PUCCH which is an uplink control channel.

[0064] After channel coding and modulation, the DCI may be transmitted through a physical downlink control channel (PDCCH, which may be interchangeably referred to as control information) or an enhanced PDCCH (EPDCCH, which may be interchangeably referred to as enhanced control information).

[0065] Typically, DCI is channel-coded for each terminal, scrambled with a radio network temporary identifier (or terminal identifier), cyclically redundancy checked (CRC) appended, and serially channel-coded for transmission via the corresponding PDCCH. In the time domain, the PDCCH can be mapped and transmitted during the control channel transmission period. The frequency domain mapping position of the PDCCH can be determined by the ID of each terminal and can be extended across the entire system transmission band.

[0066] Downlink data can be transmitted through the Physical Downlink Shared Channel (PDSCH), which is a physical channel for downlink data transmission. The PDSCH can be transmitted after the control channel transmission period, and scheduling information such as detailed mapping position in the frequency domain and modulation scheme can be indicated by DCI transmitted via the PDCCH.

[0067] The base station notifies the terminal of the modulation scheme applied to the PDSCH to be transmitted and the size of the data to be transmitted (e.g., transport block size (TBS)) using the 5-bit MCS in the control information constituting the DCI. The TBS corresponds to the size given before channel coding for error correction is applied to the data to be transmitted by the base station (e.g., transport block (TB)).

[0068] The modulation schemes supported by the LTE system may include Quadrature Phase Shift Keying (QPSK), 16-QAM, and 64-QAM, and they have modulation orders (Q m ) 2, 4, and 6. That is, QPSK modulation transmits 2 bits per symbol, 16QAM transmits 4 bits per symbol, and 64QAM transmits 6 bits per symbol. 256QAM or higher order modulation schemes may also be used.

[0069] Figure 2 is a block diagram showing a basic time-frequency resource structure for transmitting uplink data or control channels in an LTE-A system.

[0070] exist Figure 2 In the example, the horizontal axis represents time, and the vertical axis represents frequency. The minimum transmission unit in the time domain is the SC-FDMA symbol, and N symb UL SC-FDMA symbols 202 form a time slot 206. Two time slots form a subframe 205. The minimum transmission unit in the frequency domain is a subcarrier, and the entire system transmission bandwidth is determined by N BW N subcarriers 204. BW Proportional to the system transmission bandwidth.

[0071] In the time-frequency domain, the basic resource unit is RE 212, and each RE is defined by an SC-FDMA symbol index and a subcarrier index. RB or PRB 208 is defined by N in the time domain. symb UL consecutive SC-FDMA symbols and N in the frequency domain sc RB Therefore, one RB is defined by N consecutive subcarriers. symb UL xN sc RB The PUCCH is mapped to a frequency region corresponding to one RB and is transmitted during a time period of one subframe.

[0072] The LTE standard defines the relationship between the PDSCH or PDCCH / EPDCCH carrying a semi-persistent scheduling (SPS) release and the PUCCH or physical uplink shared channel (PUSCH) carrying the HARQ ACK / NACK corresponding to the PDSCH, PDCCH, or EPDCCH. For example, in an LTE system operating in FDD mode, the HARQ ACK / NACK corresponding to the PDSCH or PDCCH or EPDCCH carrying an SPS release is carried in the PUCCH or PUSCH transmitted in the nth subframe, where the PDSCH, PDCCH, or EPDCCH is transmitted in the (n-4)th subframe.

[0073] LTE uses an asynchronous HARQ scheme for DL HARQ. That is, if the eNB receives a HARQ NACK for the originally transmitted data from the UE, it can freely determine the retransmission timing through scheduling operations. If the UE fails to decode the received data, it stores the erroneous original data and combines the buffered data with the retransmitted data.

[0074] The UE transmits the HARQ ACK / NACK corresponding to the PDSCH received at subframe nk to the base station at subframe n, and k is determined differently depending on the duplex mode (i.e., FDD or time division duplex (TDD)) and the subframe configuration used by the LTE system. For example, k is fixed to 4 in an FDD LTE system. Meanwhile, k can vary depending on the subframe configuration and subframe index in a TDD LTE system. When data is transmitted on multiple carriers, the value of k can vary with the TDD configuration of each carrier. In TDD, the value of k is determined according to the TDD UL-DL configuration, as shown in Table 2.

[0075] [Table 2]

[0076]

[0077] The LTE system adopts a synchronous HARQ scheme with fixed data transmission timing for UL transmission, which is different from DL HARQ. That is, the UL-DL timing relationship between the PUSCH and the PDCCH following the PUSCH and the Physical Hybrid Indicator Channel (PHICH) carrying the DL HARQ ACK / NACK corresponding to the PUSCH is fixed according to the following rules.

[0078] If the UE receives a PDCCH carrying UL scheduling control information or a PHICH carrying DL HARQ ACK / NACK from the eNB at subframe n, it transmits UL data via the PUSCH at subframe n+k based on the control information. Here, k is determined differently depending on the duplex mode used, i.e., FDD or TDD, and its configuration. For example, in an FDD LTE system, k is fixed to 4. At the same time, k can vary according to the subframe configuration and subframe index in a TDD LTE system. When data is transmitted on multiple carriers, the value of k can also vary with the TDD configuration of each carrier. In TDD, the value of k is determined according to the TDD UL-DL configuration, as shown in Table 3.

[0079] [Table 3]

[0080]

[0081] At the same time, a PHICH carrying the HARQ ACK corresponding to the PUSCH received in subframe ik is received in subframe i. In an FDD system, k is fixed to 4. That is, in an FDD system, a PHICH carrying the HARQ-ACK corresponding to the PUSCH received in subframe ik is transmitted in subframe i. In a TDD system, if a UE not configured with EIMTA has one serving cell or multiple serving cells with the same TDD UL-DL configuration, the value of k can be given for TDD UL-DL configurations 1 to 6, as shown in Table 4.

[0082] [Table 4]

[0083]

[0084] For example, in TDD UL-DL configuration 1, a PHICH transmitted at subframe 6 may carry HARQ ACK corresponding to a PUSCH transmitted at subframe 2 four subframes prior.

[0085] In TDD UL-DL configuration 0, if HARQ ACK is received on the PHICH resource corresponding to IPHICH=0, this means that the HARQ ACK corresponds to the PUSCH transmitted at subframe ik, and the value of k is given according to Table 4. In TDD UL-DL configuration 0, if HARQ ACK is received on the PHICH resource corresponding to IPHICH=1, this means that the HARQ ACK corresponds to the PUSCH transmitted at subframe i-6.

[0086] Although the above description is directed to an LTE system, the principles of the present invention are not limited to the LTE system and can be applied to other wireless communication systems including the 5G NR system. When the present invention is applied to another wireless communication system, the value of k can be changed according to the modulation scheme used for FDD.

[0087] Figure 3 and Figure 4 is a diagram illustrating frequency-time resources allocated for transmitting data for eMBB, URLLC, and mMTC services considered in a 5G or NR system.

[0088] Figure 3 and 4 Shows how frequency and time resources are allocated for information transmission in the system.

[0089] exist Figure 3 In the example, eMBB, URLLC, and mMTC data are allocated across the entire system frequency band 300. If URLLC data 303, 305, and 307 are generated for transmission in a specific frequency band during the transmission of eMBB data 301 and mMTC data 309, portions of eMBB data 301 and mMTC data 309 may be punctured to allow insertion of URLLC data 303, 305, and 307. Because URLLC services are delay-sensitive among these services, URLLC data 303, 305, and 307 may occupy a portion of the resources allocated for eMBB data 301. When URLLC data is transmitted on resources allocated for eMBB data, the eMBB data may not be transmitted on overlapping frequency-time resources, which may reduce eMBB data transmission throughput. In other words, in this scenario, resource allocation for URLLC data transmission may result in eMBB data transmission failure.

[0090] exist Figure 4 In [1], the system frequency band 400 is divided into sub-bands 402, 404, and 406 for data transmission of different services. Sub-band configuration information can be pre-configured and transmitted from the base station to the terminal. The base station or network node can also share the sub-band to provide corresponding services without separately transmitting the sub-band configuration information to the terminal. Figure 4 In the example, subbands 402, 404, and 406 are allocated for eMBB data transmission, URLLC data transmission, and mMTC data transmission, respectively.

[0091] Throughout the embodiments, the transmission time interval (TTI) for URLLC transmission can be shorter than the TTI for eMBB or mMTC transmission. Acknowledgements corresponding to URLLC data can be transmitted faster than acknowledgments corresponding to eMBB or mMTC data, resulting in low-latency information transmission / reception.

[0092] Figure 5 is a diagram illustrating a process for dividing a transport block into a plurality of code blocks and adding CRC to the code blocks.

[0093] refer to Figure 5 , a CRC 503 may be added at the beginning or end of a transport block (TB) 501 for transmission in an uplink or downlink. The CRC may have a fixed length of 16 bits or 24 bits or a variable length that varies with channel conditions, and may be used to determine whether channel coding is successful. The block including the TB 501 and the CRC 503 may be divided into a plurality of code blocks (CBs) 507, 509, 511, and 513, as indicated by reference numeral 505. Each CB may have a predetermined maximum size as much as possible, and in this case, the size of the last CB 513 may be smaller than that of the other code blocks; 0s, random values, or 1s may be added to the last CB to make the length of the last CB equal to that of the other CBs. CRCs 517, 519, 521, and 523 may be added to the corresponding CBs. The CRC may have a fixed length of 16 bits, 24 bits, etc., and may be used to determine whether channel coding is successful. However, depending on the type of channel code to be applied to the CB, the addition of CRC 503 to the TB and the addition of CRCs 517, 519, 521, and 523 to the corresponding CB may be omitted. For example, when an LDPC code is applied instead of a turbo code, the addition of CRCs 517, 519, 521, and 523 to the corresponding CB may be omitted. However, even when an LDPC code is applied, the addition of CRCs 517, 519, 521, and 523 to the CB may be omitted. Even when a polar code is used, the addition of a CRC to the CB may be omitted.

[0094] In the following description, eMBB services are referred to as first-type services, and eMBB service data are referred to as first-type data. The terms "first-type service" and "first-type data" are not limited to eMBB, and may include other service types that require high-speed data transmission or broadband transmission. Meanwhile, URLLC services are referred to as second-type services, and URLLC service data are referred to as second-type data. The terms "second-type service" and "second-type data" are not limited to URLLC, and may include other service types that require low-latency, high-reliability transmission, or low-latency and high-reliability transmission. Meanwhile, mMTC services are referred to as third-type services, and mMTC service data are referred to as third-type data. The terms "third-type service" and "third-type data" are not limited to mMTC, and may include other service types that require low-speed, wide coverage, or low-power transmission. In one embodiment, the first-type service may be understood to include or exclude the third-type service.

[0095] The physical layer channel structures used to transmit the three types of services or data may be different from each other. For example, they may be different in at least one of TTI length, frequency resource allocation unit, control channel structure, and data mapping scheme.

[0096] Although three types of services and three types of data are listed above, the principles of the present invention can be applied to situations where there are a greater number of services and data types.

[0097] In one embodiment, the terms "physical channel" and "signal" used in LTE and LTE-A systems are used to explain the proposed method and apparatus. However, the principles of the present invention are applicable to other wireless communication systems as well as LTE and LTE-A systems.

[0098] As described above, the present invention defines communication operations between a terminal and a base station for transmitting first, second, and third types of services or data, and proposes a method for servicing terminals by scheduling different types of services or data for each terminal in the same system. In the present invention, the terms "first type terminal," "second type terminal," and "third type terminal" are intended to refer to terminals for which first, second, and third types of services or data are scheduled, respectively. In one embodiment, the first type terminal, the second type terminal, and the third type terminal may be the same or different.

[0099] In the following description, at least one of the PHICH, an uplink scheduling grant signal, and a downlink data signal is referred to as a first signal. In the present invention, the uplink data signal scheduled by the uplink scheduling grant and the HARQ ACK / NACK corresponding to the downlink data signal are referred to as a second signal. In the following description, if one of the signals transmitted from the base station to the UE requires a response, it may be the first signal, and the UE's response to the first signal may be the second signal. In the following description, the service type of the first signal may be divided into three categories: eMBB, mMTC, and URLLC; the second signal may be a signal corresponding to one of the service categories. For example, in LTE and LTE-A systems, PUCCH format 0 or 4 and PHICH may be considered the first signal, and the PUSCH transmitted in response thereto may be considered the second signal. In LTE and LTE-A systems, the PDSCH may be considered the first signal, and the PUCCH or PUSCH carrying the HARQ ACK / NACK corresponding to the PDSCH may be considered the second signal. The PDCCH / EPDCCH carrying the aperiodic CSI trigger may be considered as a first signal, and the PUSCH carrying channel measurement information transmitted in response thereto may be considered as a second signal.

[0100] In the following description, it is assumed that after receiving the first signal transmitted by the base station in the nth TTI, the terminal transmits the second signal at the (n+k)th TTI. If the base station notifies the terminal of the second signal transmission timing, this means that the base station sends the value of k to the terminal. It is assumed that after receiving the first signal transmitted by the base station in the nth TTI, the terminal transmits the second signal in the (k+4+a)th TTI. If the base station notifies the terminal of the second signal transmission timing, this means that the base station sends the terminal an offset value of a. The offset value can be defined in various forms, such as n+3+a and n+5+a, instead of n+4+k, and in the present invention, the offset value can also be defined in various ways.

[0101] Although the description is directed to an FDD LTE system, the principles of the present invention are also applicable to TDD and NR systems.

[0102] In the present invention, the term "high-layer signaling" refers to a signaling method for a base station to transmit a signal to a UE on a downlink data channel of a physical layer or for a UE to transmit a signal to a base station on an uplink data channel of a physical layer, and may be referred to as RRC signaling or MAC control element (CE) signaling.

[0103] Although the method for determining the timing of transmitting the second signal after receiving the first signal is described with respect to a terminal or a base station, the second signal may be transmitted in various ways. For example, a PUCCH format and PUCCH resources may be selected, and HARQ ACK / NACK information may be mapped to the PUSCH according to the conventional LTE standard. Meanwhile, the timing at which the terminal transmits the HARQ ACK / NACK information corresponding to the PDSCH as downlink data to the base station may be determined according to the method proposed in the present invention.

[0104] In this disclosure, the term "normal mode" refers to a mode that uses the transmission timing of the first and second signals used in conventional LTE and LTE-A systems. Normal mode ensures a signal processing time of approximately 3 milliseconds, including the time interval (TA). For example, in an FDD LTE system operating in normal mode, after receiving the first signal at subframe n, the UE transmits the second signal at subframe n+4. In this disclosure, this transmission is referred to as n+4 timing transmission. If the second signal corresponding to the first signal transmitted at subframe n+k is scheduled for transmission at n+4 timing, this means that the second signal is transmitted at subframe n+k+4. Meanwhile, n+4 timing in TDD can mean adhering to a pre-agreed timing relationship, assuming that the earliest subframe in which the second signal corresponding to the first signal transmitted at subframe n can be transmitted is subframe n+4. In a TDD system, subframe n+4 may not be an uplink subframe, and in this case, the terminal cannot transmit the second signal at subframe n+4. Therefore, it is necessary to define a timing relationship for transmitting the second signal; if the timing relationship is defined assuming that the earliest timing is subframe n+4, it can be referred to as n+4 timing. Meanwhile, if n+3 timing transmission is used in a TDD system, this may mean adhering to a pre-agreed timing relationship, assuming that the earliest subframe in which a second signal corresponding to a first signal transmitted at subframe n can be transmitted is subframe n+3. Similarly, a timing relationship for transmitting the second signal needs to be defined; if the timing relationship is defined assuming that the earliest timing is subframe n+3, it may be referred to as n+3 timing.

[0105] In the present invention, the term "delay reduction mode" refers to a mode for reducing delay by making the transmission timing of a second signal corresponding to a first signal earlier than or equal to the transmission timing in normal mode. In delay reduction mode, the timing can be controlled in various ways. In the present invention, the term "delay reduction mode" can be interchangeably referred to as reduced processing time mode. Delay reduction mode can be configured for terminals that support delay reduction mode via higher-layer signaling. A terminal configured in delay reduction mode can transmit the second signal in a subframe prior to subframe n+4 after receiving the first signal in subframe n. For example, a terminal configured in delay reduction mode can transmit the second signal in subframe n+3 after receiving the first signal in subframe n. In the present invention, this type of transmission is referred to as n+3 timing transmission. If the second signal corresponding to the first signal transmitted in subframe n+1 is scheduled for transmission in n+3 timing, this means that the second signal is transmitted in subframe n+4. As another example, if the second signal corresponding to the first signal transmitted in subframe n+2 is scheduled for transmission in subframe n+3, this means that the second signal is transmitted in subframe n+5. That is, if the second signal corresponding to the first signal transmitted at subframe n+k is scheduled to be transmitted at timing n+3, this means that the second signal is transmitted at subframe n+k+3.

[0106] In the present invention, the description is directed to the case where the normal mode and the delay reduction mode have the same TTI length. However, the principle of the present invention is also applicable to the case where the TTI lengths of the normal mode and the delay reduction mode are different.

[0107] In an embodiment of the present invention, if the first signal is a PDSCH, the second signal may be a PUSCH or PUCCH carrying HARQ ACK corresponding to the PDSCH. If the first signal is a PHICH or a PDCCH / EPDCCH carrying uplink scheduling information, the second signal may be a PUSCH scheduled by the uplink scheduling information. If the first signal is a PDCCH / EPDCCH carrying aperiodic CSI trigger, the second signal may be a PUSCH carrying channel measurement information.

[0108] Since it is uncertain when the base station transmits a high-layer signal to configure the terminal in the delay reduction mode, a terminal is required to transmit a second signal to the base station at a predetermined timing that is independent of the configuration. For example, although the base station configures the terminal in the delay reduction mode to comply with the n+3 timing transmission, the terminal cannot know the timing at which the delay reduction mode configuration becomes effective. Therefore, a method is required to allow the terminal to perform transmission according to the n+4 timing transmission. That is, a method for performing n+4 timing transmission regardless of how the delay reduction mode is configured may be required. In the present invention, the method for performing n+4 timing transmission regardless of how the delay reduction mode is configured is referred to as fallback mode transmission. If fallback mode transmission is enabled, the base station performs an uplink reception operation assuming that the second signal is transmitted with n+4 timing instead of n+3 and n+2 timing.

[0109] The fallback mode transmission may be performed by at least one of: 1) transmitting the first signal in a predetermined DCI format, 2) transmitting DCI for transmitting the first signal in a predetermined search space, and 3) transmitting the DCI by using a predetermined RNTI value.

[0110] The predetermined search space may be one of a cell-specific search space (CSS) and a UE-specific search space (USS), which are defined as follows: The index of a control channel element (CCE) to which a control channel of aggregation level L and a downlink control signal are mapped in subframe k may be calculated as follows.

[0111]

[0112] In CSS, Yk is defined as 0 for aggregation levels 4 and 8. In USS, Y k =(AY k-1 )mod D,Y -1 =n RNTI (not 0), A=39827, D=65537, and And represents a slot index in a radio frame. Here, x mody may represent a remainder obtained by dividing x by y. Here, M (L) Indicates multiple downlink control channels of aggregation level L. Here, m is 0 to M (L) Natural values in the range (in CSS, m'=m, and in USS, m'=m+M (L) nCI ), and n CI It can be the carrier indicator field value. (L) The value of can be defined as shown in Table 5.

[0113] [Table 5]

[0114]

[0115] In the CSS, the CCE index from which control signal mapping starts is determined to be 0, 4, 8, or 12 at aggregation level 4, and is determined to be 0 or 8 at aggregation level 8. In the USS, it may vary with an RNTI value which is an identifier of a terminal.

[0116] In the case of fallback mode transmission using method 1) for transmitting a first signal in a predetermined DCI format, by way of example, when downlink scheduling is performed using DCI format 1A in a conventional LTE system, the second signal can always be transmitted at timing n+k, regardless of the delay reduction mode configuration of the base station. That is, even if the terminal is configured to transmit the second signal at timing n+3, if downlink scheduling is performed using DCI format 1A, the terminal transmits the second signal at timing n+4.

[0117] In the case of using method 2) for fallback mode transmission of DCI for transmitting a first signal in a predetermined search space, when DCI is transmitted in an area configured as a cell-common search space, regardless of the delay reduction mode configuration of the base station, the second signal corresponding to the first signal associated with the DCI can always be transmitted at n+4 timing. That is, even if the terminal is configured to transmit the second signal at n+3 timing, if DCI is received in the cell-common search space, the terminal transmits the second signal at n+4 timing.

[0118] In the case of fallback mode transmission using method 3) for transmitting DCI with a predetermined RNTI value, when the base station configures the terminal with an RNTI for fallback mode transmission and transmits the PDCCH / EPDCCH carrying the DCI to the RNTI, the second signal corresponding to the first signal associated with the DCI can always be transmitted at timing n+4, regardless of the delay reduction mode configuration of the base station. That is, even if the terminal is configured to transmit the second signal at timing n+3, if the PDCCH / EPDCCH is successfully decoded using the RNTI, the terminal transmits the second signal at timing n+4.

[0119] Figure 6This flowchart illustrates an uplink transmission method for a terminal when a base station configures the terminal for delay reduction mode and transmits a first signal in step 601. Upon receiving the first signal from the base station in step 601, the terminal checks the first signal in step 603 to determine whether it indicates fallback mode transmission. If the first signal is determined to indicate fallback mode transmission in step 603, the terminal transmits a second signal at n+4 timing, regardless of the delay reduction mode configuration. If the first signal is determined not to indicate fallback mode transmission in step 603, the terminal transmits the second signal at step 607 at a timing determined according to the delay reduction mode configuration, e.g., n+3 or n+2 timing.

[0120] In one embodiment of the present invention, different methods of the present invention may be identified by distinguishing numbers such as 1), 2), and 3).

[0121] In the present invention, there are two transmission modes: a normal mode in which the earliest transmission timing of a second signal corresponding to a first signal transmitted at subframe n is subframe n+4; and a delay reduction mode or signal processing time reduction mode in which the earliest transmission timing of a second signal corresponding to a first signal transmitted at subframe n is subframe n+2 or n+3. Subframe n+4, which is the transmission timing for distinguishing between the normal mode and the delay reduction mode, can be changed to an alternative timing in the present invention.

[0122] In the present invention, a method for operating in fallback mode with n+4 timing in the case where DCI is detected in a predetermined search space is described. That is, in the case where fallback mode transmission is enabled when the DCI that schedules the transmission of the first signal is transmitted in the predetermined search space, if the DCI is received in an area configured as a common search space (CSS), the second signal corresponding to the first signal associated with the DCI can always be transmitted with n+4 timing, regardless of the delay reduction mode configuration of the base station. In this case, although the terminal is configured to transmit the second signal with n+3 timing, if the DCI is received in the CSS, the terminal transmits the second signal with n+4 timing. However, if the DCI is received in the UE-specific search space (USS), the terminal transmits the second signal with n+3 timing as configured.

[0123] Conventional LTE terminals attempt to decode DCI formats that vary depending on the transmission mode. For example, a terminal configured in transmission mode 4 may attempt to detect DCI format 1A in the CSS and USS for receiving the PDSCH transmitted to the C-RNTI, and attempt to detect DCI format 2 in the USS. Therefore, in the above example, if the delay reduction mode is configured to n+3 timing, when the terminal detects DCI format 1A in the CSS, the fallback mode to n+4 timing is triggered. An object of the present invention is to provide an operating method for a terminal and a base station when the search space in which the terminal attempts to detect DCI format 1A is the CSS and is also the USS. That is, problems arise when the CSS and the USS overlap. For example, if the aggregation level is 4 or 8, each search space consisting of 4 or 8 CCEs may be included in both the CSS and the USS. If for a terminal configured for n+3 timing in delay reduction mode, a certain search space is CSS and is also USS, and if the terminal detects DCI format 1A in the search space, the terminal may not be sure whether the timing for transmitting HARQ ACK feedback corresponding to downlink data scheduled using the detected DCI format 1A is n+3 timing or n+4 timing. The present invention proposes an operating method of a terminal and a base station for solving this problem. In the present invention, the term "first search space" can be interchangeably referred to as a cell-specific search space (CSS), and the term "second search space" can be interchangeably referred to as a UE-specific search space (USS). In the present invention, the terms "detection" and "decoding" can be used interchangeably and have the same meaning.

[0124] In the present invention, the fallback mode can be enabled when the base station configures the delay reduction mode to the terminal, but it is not used in the normal mode. In the present invention, the second signal corresponding to the downlink control signal can be a HARQ ACK corresponding to the downlink data scheduled by the control signal, or uplink data scheduled by the uplink grant transmitted in the control signal.

[0125] [Example 1]

[0126] Embodiment 1 relates to a method for prioritizing a first search space over a second search space when a terminal successfully decodes a downlink control signal in a search space that is both a first search space and a second search space, and the method refers to Figure 7 and 8 To describe.

[0127] When the base station has configured the terminal to transmit a second signal at timing n+3 in delay reduction mode, the terminal may enable fallback mode to transmit the second signal at timing n+4 if the downlink control signal is decoded in the first search space, and at timing n+3 if the downlink control signal is decoded in the second search space. However, if the search space used to decode the downlink control signal is both the first search space and the second search space, the terminal may treat the search space as the first search space. In other words, when the search space used to decode the downlink control signal is both the first search space and the second search space, the terminal may treat the search space as the first search space. Therefore, if the search space used to decode the downlink control signal is both the first search space and the second search space, the terminal transmits the corresponding second signal to the base station at timing n+4. In other words, if the downlink control signal is decoded in the first search space, the terminal transmits the corresponding second signal to the base station at timing n+4, and if the downlink control signal is decoded in a search space other than the first search space, the terminal transmits the corresponding second signal to the base station at timing n+3. That is, if a downlink control signal is decoded in the first search space, the terminal enables a fallback mode for transmitting a second signal at n+4 timing. This method can be applied in association with a control signal format that can be transmitted in the first search space and the second search space, and different methods can be used in association with a specific control signal that can be transmitted only in the second search space. If the terminal detects a control signal that can only be transmitted in the second search space of a search space that is both the first search space and the second search space, the corresponding search space can be regarded as the second search space. For example, the method according to embodiment 1 can be used to detect DCI format 1A, and DCI that is transmitted only in the USS, such as DCI format 2, can always be detected in the second search space. In an FDD system, if the terminal detects DCI format 1A in the CSS, the second signal is transmitted at n+4 timing. In a TDD system, if the terminal detects DCI format 1A in the CSS, the second signal is transmitted by using a timing defined by assuming that the earliest timing is n+4 timing.

[0128] Figure 7 A flowchart illustrating an operating method of the base station according to Embodiment 1 is shown. Figure 7Part (a) is a flowchart showing a method for a base station to map a control signal to a search space. In step 701, the base station configures the terminal in a delay reduction mode and encodes the downlink control signal to be transmitted. In step 703, the base station determines in step 703 whether the terminal must transmit a second signal corresponding to the control signal and the first signal with n+4 timing or n+3 timing. If it is determined that the terminal must transmit the second signal with n+4 timing, the base station maps the downlink control signal to the first search space in step 705. If it is determined that the terminal must transmit the second signal with n+3 timing, then in step 707, the base station maps the downlink control signal to the second search space instead of the first search space. Thereafter, in step 709, the base station transmits the mapped control signal through the control channel.

[0129] Figure 7 Part (b) is a flowchart showing a method for a base station to determine the timing for receiving a second signal corresponding to a control signal based on the search space to which the control signal is mapped. In step 711, the base station configures the terminal in a delay reduction mode, encodes the downlink control signal, and maps the control signal to the search space. In step 713, the base station determines whether the control signal is mapped to the first search space. If it is determined that the control signal is mapped to the first search space, the base station receives the second signal corresponding to the first signal at n+4 timing in step 715. If it is determined that the control signal is not mapped to the first search space, in step 717, the base station receives the second signal corresponding to the first signal at n+3 timing.

[0130] Figure 8 A flowchart illustrating an operating method of a terminal according to Embodiment 1 is shown. Figure 8 Part (a) is a flowchart illustrating a method in which a terminal determines the timing for transmitting a second signal based on a search space in which a control signal is detected. In step 801, a terminal configured in a delay reduction mode receives a signal and performs control signal decoding. In step 803, the terminal determines whether the search space in which the control signal is detected is the first search space and is also the second search space. If it is determined that the search space in which the control signal is detected is the first search space and is also the second search space, the terminal transmits the second signal corresponding to the first signal to the base station at n+4 timing in step 805. If it is determined that the search space in which the control signal is detected is not the first search space and the second search space at the same time, the terminal determines in step 807 whether the search space is the first search space; if so, in step 805, the terminal transmits the second signal corresponding to the first signal to the base station at n+4 timing. If it is determined that the search space in which the control signal is detected is not the first search space, then in step 809, the terminal transmits the second signal corresponding to the first signal to the base station at n+3 timing.

[0131] Figure 8 Part (b) is a flowchart illustrating another method in which a terminal determines the timing for transmitting a second signal based on the search space in which the control signal was detected. In step 811, the terminal configured in the delay reduction mode receives a signal and performs control signal decoding. In step 813, the terminal determines whether the search space in which the control signal was detected is the first search space. If so, in step 815, the terminal transmits the second signal corresponding to the first signal to the base station at n+4 timing. If it is determined that the search space in which the control signal was detected is not the first search space, in step 817, the terminal transmits the second signal corresponding to the first signal to the base station at n+3 timing.

[0132] Considering that when the channel conditions of a normal terminal deteriorate or when a specific DCI format such as DCI format 1A that can be transmitted in the first search space and the second search space is used during high-layer signaling, the base station and the terminal can be designed to operate as described in this embodiment, assuming that a DCI format such as DCI format 1A is used for special cases.

[0133] [Example 2]

[0134] Embodiment 2 relates to a method for prioritizing the second search space over the first search space when the terminal successfully decodes a downlink control signal in a search space that is both the first search space and the second search space, and the method with reference to Figure 9 and 10 To describe.

[0135] When the base station has configured the terminal in delay reduction mode to transmit a second signal at timing n+3, the terminal can enable fallback mode to transmit the second signal at timing n+4 if the downlink control signal is decoded in the first search space, and at timing n+3 if the downlink control signal is decoded in the second search space. However, if the search space in which the downlink control signal is decoded is both the first search space and the second search space, the terminal may treat the search space as the second search space. In other words, if the search space in which the downlink control signal is decoded is both the first search space and the second search space, the terminal may treat the search space as the second search space. Therefore, if the search space in which the downlink control signal is decoded is both the first search space and the second search space, the terminal transmits the corresponding second signal to the base station at timing n+3. In other words, if the downlink control signal is decoded in the second search space, the terminal transmits the corresponding second signal to the base station at timing n+3, and if the downlink control signal is decoded in a search space other than the second search space, the terminal transmits the corresponding second signal to the base station at timing n+4. That is, if a downlink control signal is decoded in a search space that is not the second search space, the terminal enables a fallback mode for transmitting the second signal at n+4 timing. This method is applicable to control signal formats that can be transmitted in the first search space and the second search space, and different methods can be used for specific control signals that can only be transmitted in the second search space. If the terminal detects a control signal that can only be transmitted in the second search space in a search space that is both the first search space and the second search space, the corresponding search space can be regarded as the second search space. For example, the method according to embodiment 2 can be used to detect DCI format 1A, and DCI that is transmitted only in the USS, such as DCI format 2, can always be detected in the second search space. In an FDD system, if the terminal detects DCI format 1A in a search space that is not the USS, the second signal is transmitted at n+4 timing. In a TDD system, if the terminal detects DCI format 1A in a search space that is not the USS, the second signal is transmitted using timing defined by assuming that the earliest timing is n+4 timing.

[0136] Figure 9 A flowchart illustrating an operating method of a base station according to Embodiment 2 is shown. Figure 9Part (a) shows a flowchart of a method in which a base station maps a control signal to a search space. In step 901, the base station configures the terminal in a delay reduction mode and encodes the downlink control signal to be transmitted. In step 903, the base station determines whether the terminal must transmit a second signal corresponding to the control signal and the first signal with n+4 timing or n+3 timing. If it is determined that the terminal must transmit the second signal with n+4 timing, then in step 905, the base station maps the downlink control signal to the first search space instead of the second search space. If it is determined that the terminal must transmit the second signal with n+3 timing, then in step 907, the base station maps the downlink control signal to the second search space. Thereafter, in step 909, the base station transmits the mapped control signal through the control channel.

[0137] Figure 9 Part (b) is a flowchart showing a method for a base station to determine the timing for receiving a second signal corresponding to a control signal based on the search space to which the control signal is mapped. In step 911, the base station configures the terminal to a delay reduction mode, encodes the downlink control signal, and maps the control signal to the search space. In step 913, the base station determines whether the control signal is mapped to the second search space. If it is determined that the control signal is mapped to the second search space, then in step 915, the base station receives the second signal corresponding to the first signal at n+3 timing. If it is determined that the control signal is not mapped to the second search space, then in step 917, the base station receives the second signal corresponding to the first signal at n+4 timing.

[0138] Figure 10 A flowchart illustrating an operating method of a terminal according to Embodiment 2 is shown. Figure 10 Part (a) is a flowchart illustrating a method in which a terminal determines the timing for transmitting a second signal based on the search space in which a control signal is detected. In step 1001, a terminal configured in a delay reduction mode receives a signal and performs control signal decoding. In step 1003, the terminal determines whether the search space in which the control signal is detected is a search space that is both the first search space and the second search space. If it is determined that the search space in which the control signal is detected is a search space that is both the first search space and the second search space, then in step 1005, the terminal transmits a second signal corresponding to the first signal to the base station at n+3 timing. If it is determined that the search space in which the control signal is detected is not both the first search space and the second search space, then in step 1007, the terminal determines whether the search space is the second search space; if so, then in step 1005, the terminal transmits the second signal corresponding to the first signal to the base station at n+3 timing. If it is determined that the search space in which the control signal is detected is not the second search space, then in step 1009, the terminal transmits the second signal corresponding to the first signal to the base station at n+4 timing.

[0139] Figure 10 Part (b) is a flowchart illustrating another method in which a terminal determines the timing for transmitting a second signal based on the search space in which the control signal was detected. In step 1011, the terminal configured in the delay reduction mode receives a signal and performs control signal decoding. In step 1013, the terminal determines whether the search space in which the control signal was detected is the second search space. If so, in step 1015, the terminal transmits the second signal corresponding to the first signal to the base station at n+3 timing. If it is determined that the search space in which the control signal was detected is not the second search space, in step 1017, the terminal transmits the second signal corresponding to the first signal to the base station at n+4 timing.

[0140] Because it is assumed in this embodiment that the base station and the terminal have previously agreed to use n+3 timing transmission via higher layer signaling, the base station and the terminal prioritize n+3 timing transmission over n+4 timing transmission.

[0141] [Example 3]

[0142] Embodiment 3 relates to a method for configuring a terminal to prioritize one search space over another search space when the terminal successfully decodes a downlink control signal in a search space that is simultaneously a first search space and a second search space, and to reference Figure 11 Describe the method.

[0143] In step 1101, the base station configures the terminal with a delay reduction mode and a prioritized search space via higher layer signaling. For example, if the search space is both the first search space and the second search space, the base station may transmit configuration information including a variable (i.e., prioritized_common_search_space) via higher layer signaling for the terminal to use in determining whether to treat the search space as the first search space or the second search space. In this embodiment, if the variable (i.e., prioritized_common_search_space) is set to a value of TRUE, the terminal treats the search space as the first search space, which causes the process to proceed to step 1105, and if the variable is set to a value of FALSE, the terminal treats the search space as the second search space, which causes the process to proceed to step 1107.

[0144] In the case where the search space is both the first search space and the second search space, if the terminal regards the search space as the first search space, then in step 1105 , the base station and the terminal perform the transmission / reception operations as described in the first embodiment.

[0145] In the case where the search space is both the first search space and the second search space, if the terminal regards the search space as the second search space, then in step 1107 , the base station and the terminal perform the transmission / reception operations as described in the second embodiment.

[0146] This method can be applied in association with control signal formats that can be transmitted in both the first search space and the second search space, and a different method can be used in association with specific control signals that can be transmitted only in the second search space. If a terminal detects a control signal that can only be transmitted in the second search space of a search space that is both the first search space and the second search space, the corresponding search space can be considered the second search space. For example, the method according to Embodiment 3 can be used to detect DCI format 1A, and DCI transmitted only in the USS, such as DCI format 2, can always be detected in the second search space.

[0147] [Example 4]

[0148] Embodiment 4 relates to a method for using transmission timing that has been used for previous downlink data transmission when a terminal successfully decodes a downlink control signal in a search space that is simultaneously a first search space and a second search space, and Figure 12 to describe the method.

[0149] If the base station configures the terminal to transmit a second signal at n+3 timing in delay reduction mode, the terminal may transmit the second signal at n+4 timing if a downlink control signal is decoded in the first search space, and enable fallback mode to transmit the second signal at n+3 timing if a downlink control signal is decoded in the second search space. However, if the search space used to decode the downlink control signal is both the first search space and the second search space, the terminal may transmit the second signal at the transmission timing used to transmit the second signal corresponding to the previously received control signal. That is, if the currently received control signal is decoded in a search space that is both the first search space and the second search space, the terminal uses the transmission timing of the second signal that has been determined based on the control signal scheduled by the most recently received downlink data or the most recently transmitted uplink data in the control signal received in the previous subframe. If the second signal corresponding to the most recently received control signal has already been transmitted at n+3 timing, the terminal transmits the second signal corresponding to the currently received control signal at n+3 timing. If the second signal corresponding to the most recently received control signal has already been transmitted at n+4 timing, the terminal transmits the second signal corresponding to the currently received control signal at n+4 timing. This method is used by base stations and terminals to reuse recently performed transmission / reception operations. This method can be applied to control signal formats that can be transmitted in both the first search space and the second search space, and different methods can be used for specific control signals that can be transmitted only in the second search space. If a terminal detects a control signal that can only be transmitted in the second search space of a search space that is both the first search space and the second search space, the corresponding search space can be regarded as the second search space. For example, the method according to embodiment 4 can be used to detect DCI format 1A, and DCI that is transmitted only in the USS, such as DCI format 2, can always be detected in the second search space.

[0150] Figure 12Part (a) is a flowchart illustrating the operation of a base station according to an embodiment of the present invention. In step 1201, the base station configures the terminal in a delay reduction mode, encodes a downlink control signal, and maps the control signal. In step 1203, the base station determines whether the search space to which the control signal is mapped is both the first search space and the second search space. If the search space to which the control signal is mapped is both the first search space and the second search space, then in step 1205, the base station attempts to receive the second signal corresponding to the current control signal with a transmission timing that has been used to receive the second signal corresponding to the control signal most recently transmitted to the terminal. For example, if the second signal corresponding to the control signal transmitted in the previous subframe for scheduling downlink data to the terminal has been transmitted with n+4 timing, the terminal determines to use n+4 timing for transmitting the second signal corresponding to the control signal transmitted in the current subframe.

[0151] Figure 12 Part (b) is a flowchart illustrating the operation of a terminal according to an embodiment of the present invention. In step 1211, the terminal configured in the delay reduction mode receives a signal and performs control signal decoding. In step 1213, the terminal determines whether the search space in which the control signal is detected is a search space that is both the first search space and the second search space. If it is determined that the search space in which the control signal is detected is a search space that is both the first search space and the second search space, then in step 1215, the terminal transmits the second signal corresponding to the current control signal to the base station at the transmission timing for transmitting the second signal corresponding to the most recently received control signal. If it is determined that the search space in which the control signal is detected is not a search space that is both the first search space and the second search space, then in step 1217, for the case where the control signal is mapped to the first search space, the terminal transmits the corresponding second signal at n+4 timing, and for the case where the control signal is mapped to the second search space, the terminal transmits the corresponding second signal at n+3 timing.

[0152] [Example 4-1]

[0153] Embodiment 4-1 relates to a method for using, when a terminal successfully decodes a downlink control signal in a search space that is simultaneously a first search space and a second search space, a timing previously used for downlink data transmission in a case where a predetermined condition is satisfied, and using a pre-agreed timing in a case where the condition is not satisfied, and Figure 13 Describe the method.

[0154] Figure 13This is a flowchart illustrating a method for determining the timing of second signal transmission between a base station and a terminal based on whether a control signal was transmitted / received in the most recent subframe. In step 1301, the base station configures the terminal in delay reduction mode, encodes a downlink control signal, and maps the control signal. The terminal configured in delay reduction mode receives the signal and decodes the control signal. In step 1303, the base station and the terminal determine whether a control signal triggering transmission of the second signal has been transmitted / received in the most recent k subframes. Here, k can be a pre-agreed value. For example, k can be set to 4 or 10, or a value indicating the current radio frame. k can also be set to a value indicating the most recent subframe. If a control signal was received in the most recent k subframes and triggered transmission of the second signal, the timing for transmitting the second signal is reused in step 1305. In this case, the base station and the terminal can operate according to embodiment 4. If a control signal triggering transmission of the second signal has not been received in the most recent four subframes, the base station and the terminal can perform transmission / reception operations according to embodiments 1, 2, or 3 in step 1307.

[0155] [Example 5]

[0156] Embodiment 5 relates to a method for a base station to receive HARQ ACK feedback or a second signal corresponding to data when the base station transmits a control signal for scheduling downlink data transmission in a search space that is simultaneously a first search space and a second search space, and to Figure 14 Describe the method.

[0157] Figure 14 1401 is a flowchart showing the operation of the base station according to Example 5. In step 1401, the base station configures the terminal in the delay reduction mode, encodes the downlink control signal to be transmitted, and maps the control signal. The base station determines whether the search space to which the control signal is mapped is both the first search space and the second search space. If it is determined that the search space to which the control signal is mapped is both the first search space and the second search space, then in step 1405, the base station may attempt to detect the second signal corresponding to the control signal at both n+3 timing and n+4 timing. If it is determined that the search space to which the control signal is mapped is not both the first search space and the second search space, then in step 1407, the base station attempts to detect the second signal at n+4 timing for the case where the control signal is mapped to the first search space, and at n+3 timing for the case where the control signal is mapped to the second search space.

[0158] This method can be applied in association with a control signal format that can be transmitted in both the first search space and the second search space, and a different method can be used in association with a specific control signal that can be transmitted only in the second search space. If the base station has already transmitted a control signal in a search space that is both the first search space and the second search space (which can be transmitted only in the second search space), an attempt can be made to detect the second signal corresponding to the control signal only at n+3 timing. For example, the method according to embodiment 5 can be used to transmit DCI format 1A and detect the corresponding second signal, and n+3 timing can be used in delay reduction mode to transmit DCI that can be transmitted only in the USS, such as DCI format 2, and detect the corresponding second signal.

[0159] In the above embodiments, the delay reduction mode operation is described in conjunction with n+3 timing to help understand the present invention but not to limit the scope of the present invention. Therefore, the present invention is applicable to a system configured to transmit the second signal at n+2 or n+3 timing in the delay reduction mode.

[0160] Each terminal and base station, which is composed of a transmitter, a receiver and a processor for implementing the method of the above embodiment, is respectively Figure 15 and 16 In order to implement the method of communication between a base station and a terminal to achieve the goal of detecting a control signal associated with a search space according to embodiments 1 to 5, the transmitter, receiver, and processor of each base station and UE should operate as described in the respective embodiments.

[0161] Figure 15 : is a block diagram showing the configuration of a terminal according to an embodiment of the present invention. Figure 15As shown, the terminal may include a processor 1502, a receiver 1500, and a transmitter 1504. According to embodiments of the present invention, receiver 1500 and transmitter 1504 may be collectively referred to as a transceiver. The transceiver can transmit and receive signals to and from a base station. The signals may include control information and data. The transceiver may include a radio frequency (RF) transmitter for frequency up-converting and amplifying the signal to be transmitted, and an RF receiver for low-noise amplification and frequency down-conversion of the received signal. The transceiver may output signals received via a radio channel to processor 1502 and transmit signals output from processor 1502 via the radio channel. According to embodiments of the present invention, processor 1502 may control the overall operation of the UE. For example, processor 1502 may control receiver 1500 to receive a signal including a control signal, determine a DCI format for decoding associated with a search space, and decode the DCI format. The processor may also determine the search space in which the DCI is detected and determine the transmission timing of a second signal. Thereafter, if a second signal corresponding to the control signal needs to be transmitted, transmitter 1504 transmits the second signal at the timing determined by the processor.

[0162] Figure 16 : is a block diagram showing the configuration of a base station according to an embodiment of the present invention. Figure 16 As shown, the base station may include a processor 1603, a receiver 1601, and a transmitter 1605. According to embodiments of the present invention, the receiver 1601 and the transmitter 1605 may be collectively referred to as a transceiver. The transceiver may transmit signals to and receive signals from a terminal. The signals may include control information and data. The transceiver may include: an RF transmitter for frequency up-converting and amplifying the signal to be transmitted; and an RF receiver for low-noise amplification and frequency down-conversion of the received signal. The transceiver may output signals received through a radio channel to the processor 1603, and transmit signals output from the processor 1603 through the radio channel. The processor 1603 may control the overall operation of the base station as described above in the embodiments of the present invention.

[0163] The embodiments disclosed in the specification and the drawings are provided to help explain and understand the present invention, rather than to limit the scope of the present invention. It is obvious to those skilled in the art that modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention. If necessary, the embodiments may be combined in whole or in part. For example, the base station and the terminal may operate according to a combination of parts of embodiments 1 and 2 of the present invention. Although the embodiments have been directed to LTE / LTE-A systems, the present invention may include alternative embodiments for other systems such as 5G NR systems without departing from the technical spirit of the present invention.

[0164] In the embodiments of the present invention, components are described in singular or plural forms according to the embodiment. However, the singular and plural forms are appropriately selected for the presented case for the sake of convenience of explanation only, and are not intended to limit the present invention thereto; therefore, unless the context clearly indicates otherwise, the singular form also includes the plural form.

[0165] Although described with reference to specific embodiments, the present invention can be implemented with various modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed, and it is intended to include the following claims and their equivalents.

Claims

1. A method performed by a terminal in a wireless communication system, the method comprising: receiving, from a base station, information configuring a plurality of search spaces of a terminal; Monitoring the physical downlink control channel PDCCH; In a case where the PDCCH is monitored in an overlapping area where a common search space CSS and a user equipment UE specific search space USS overlap, determining to monitor the PDCCH in the CSS; as well as Based on the downlink control information received on the PDCCH corresponding to the CSS, a physical uplink shared channel PUSCH is transmitted to the base station in transmission timing.

2. The method of claim 1, further comprising: Information indicating that an advanced processing time is configured for the terminal is received from a base station.

3. The method according to claim 2, wherein: The processing time according to the advanced processing time is shorter than the processing time without the advanced processing time.

4. The method according to claim 1, wherein The information for configuring multiple search spaces of the terminal is received via high-layer signaling.

5. A method performed by a base station in a wireless communication system, the method comprising: Sending information configuring multiple search spaces of the terminal to the terminal; Sending downlink control information on a physical downlink control channel (PDCCH) in an overlapping area where a common search space (CSS) and a user equipment (UE) specific search space (USS) overlap; as well as Based on the downlink control information transmitted on the PDCCH corresponding to the CSS, a physical uplink shared channel PUSCH is received from the terminal at the transmission timing, Here, when downlink control information is transmitted in the overlapping area, the downlink control information is decoded in the CSS.

6. The method according to claim 5, in, The information for configuring the multiple search spaces of the terminal is sent via high-layer signaling.

7. The method of claim 5, further comprising: Information is sent to the terminal indicating that advanced processing time is configured for the terminal.

8. The method of claim 7, wherein: The processing time according to the advanced processing time is shorter than the processing time without the advanced processing time.

9. A terminal in a wireless communication system, the terminal comprising: a transceiver configured to transmit and receive signals; as well as The controller is configured as: Receive information configuring multiple search spaces of the terminal from the base station, Monitor the physical downlink control channel PDCCH, In the case of monitoring the PDCCH in an overlapping area where a common search space CSS and a user equipment UE specific search space USS overlap, determining to monitor the PDCCH in the CSS, and Based on the downlink control information received on the PDCCH corresponding to the CSS, a physical uplink shared channel PUSCH is transmitted to the base station in transmission timing.

10. The terminal according to claim 9, in, The information for configuring multiple search spaces of the terminal is received via high-layer signaling. The terminal according to claim 9 , wherein: The controller is further configured to receive information indicating that an advanced processing time is configured for the terminal from the base station, and Here, the processing time according to the advanced processing time is shorter than the processing time without the advanced processing time.

12. A base station in a wireless communication system, the base station comprising: a transceiver configured to transmit and receive signals; as well as The controller is configured as: Send information to the terminal to configure multiple search spaces of the terminal, Downlink control information is transmitted on a physical downlink control channel (PDCCH) in an overlapping area where a common search space (CSS) and a user equipment (UE) specific search space (USS) overlap, and Based on the downlink control information transmitted on the PDCCH corresponding to the CSS, a physical uplink shared channel PUSCH is received from the terminal at the transmission timing, Here, when downlink control information is transmitted in the overlapping area, the downlink control information is decoded in the CSS.

13. The base station according to claim 12, in, The information for configuring the multiple search spaces of the terminal is sent via high-layer signaling.

14. The base station according to claim 12, wherein: The controller is further configured to send information to the terminal indicating that the advanced processing time is configured for the terminal, and Here, the processing time according to the advanced processing time is shorter than the processing time without the advanced processing time.

Images