Method and apparatus for designing HARQ codebook according to terminal capability in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate. More specifically, the present disclosure relates to a method performed by a user equipment (UE) in a wireless communication system, the method comprising the steps of: transmitting, to a base station, capability information on a maximum number of physical downlink shared channels (PDSCH) that the UE can receive in a single slot; receiving configuration information from a base station, the configuration information including first information including at least one slot offset value between each reception slot of at least one PDSCH and a transmission slot of a Hybrid Automatic Repeat Request Acknowledgement (HARQ-ACK) codebook and second information on a maximum number of PDSCHs scheduled to a single slot; determining one or more receiving time slots of the PDSCH based on the first information; generating, on the basis of the second information, a HARQ-ACK codebook including a plurality of pieces of HARQ-ACK information, the number of which corresponds to the maximum number of PDSCHs that can be scheduled to each of the one or more reception slots of the determined PDSCH, the HARQ-ACK information being configured for each of the one or more reception slots of the determined PDSCH; and sending the generated HARQ-ACK codebook to a base station.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to operations of a user equipment (UE) and a base station in a wireless communication system. In particular, the present disclosure relates to a method for transmitting a HARQ-ACK indicating whether a physical downlink shared channel has been successfully received when the UE receives the physical downlink shared channel, and a device capable of performing the method. BACKGROUND

[0002] 5G mobile communication technologies define wide frequency bands so that high transmission rates and new services are possible, and are implemented not only in "Sub 6 GHz" but also in "Above 6 GHz" bands (mmWave), e.g., 28 GHz and 39 GHz. To mitigate a propagation path loss and increase a propagation distance in the above 6 GHz bands, technologies including beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and digital beamforming are being discussed.

[0003] At the beginning of the development of 5G mobile communication technologies, in order to support services and meet performance requirements in conjunction with enhanced Mobile BroadBand (eMBB), Ultra Reliable Low Latency Communications (URLLC), and massive Machine-Type Communications (mMTC), standardization has been made on technologies including beamforming and massive MIMO for mitigating radio wave path loss and increasing radio wave transmission distances in mmWave; support of basic numerical sets (numerologies) (e.g., operation of multiple subcarrier intervals) for efficient utilization of mmWave resources and dynamic operation of slot formats; initial access techniques for supporting multi-beam transmission and wide bands; definition and operation of BWPs (BandWidth Parts); new channel coding and modulation methods such as a Low Density Parity Check (LDPC) code for large amounts of data transmission and a polar code for highly reliable transmission of control information; L2 pre-processing; and network slicing for providing a dedicated network customized for a specific service.

[0004] Currently, in view of services to be supported by 5G mobile communication technologies, there are ongoing discussions about improvements in and enhancements to initial 5G mobile communication technologies, and there has been physical layer standardization for technologies such as V2X (Vehicle-to-everything), for determining driving of autonomous vehicles based on information about positions and states of vehicles transmitted from vehicles and for enhancing user convenience, NR-U (New Radio Unlicensed) for system operation complying with various regulatory requirements in unlicensed bands, NR UE power saving, Non-Terrestrial Network (NTN) which is UE-satellite direct communication for providing coverage in an area where communication with terrestrial networks is unavailable, and positioning.

[0005] In addition, in the air interface architecture / protocol, there has been ongoing standardization for technologies such as Industrial Internet of Things (IIoT) for supporting new services through interworking and convergence with other industries, IAB (Integrated Access and Backhaul) for providing a node for network service area expansion by supporting a wireless backhaul link and an access link in an integrated manner, mobility enhancement including conditional handover and DAPS (Dual Active Protocol Stack) handover, and two-step random access for simplifying a random access procedure (2-step RACH (Random Access Channel) for NR). In the system architecture / service, there has also been ongoing standardization for 5G baseline architecture (e.g., service-based architecture or service-based interface) for combining Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) for receiving services based on positions of UEs.

[0006] As 5G mobile communication systems are commercialized, connected devices, which have exponentially increased, will be connected to communication networks, and accordingly, enhanced functionality and performance of 5G mobile communication systems and integrated operations of connected devices are expected to be necessary. To this end, new research is planned in conjunction with the following: eXtended Reality (XR) for effectively supporting AR (Augmented Reality), VR (Virtual Reality), MR (MixedReality), and the like; improvement of 5G performance and reduction of complexity by utilizing Artificial Intelligence (AI) and Machine Learning (ML); AI service support; metaverse service support; and drone communication.

[0007] In addition, such development of 5G mobile communication systems will not only serve as a basis for developing new waveforms for providing coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission techniques such as Full Dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas, lenses and antennas based on metamaterials for increasing coverage of terahertz band signals, high-dimensional spatial multiplexing techniques using OAM (Orbital Angular Momentum) and RIS (Reconfigurable Intelligent Surface), but also serve as a basis for developing full-duplex techniques for increasing frequency efficiency of 6G mobile communication technologies and improving system networks, AI-based communication techniques for implementing system optimization by utilizing satellites and AI (Artificial Intelligence) from the design stage and internalizing end-to-end AI support functions, and next-generation distributed computing techniques for implementing services with complexity levels exceeding UE operation capability limits by utilizing super-high-performance communication and computing resources.

[0008] As described above, and as the progress of mobile communication systems enables different services to be provided, there is an increasing need for efficient methods of delivering these services. SUMMARY

[0009] TECHNICAL PROBLEM

[0010] The disclosure will provide a device and method capable of efficiently providing services in a mobile communication system.

[0011] SOLUTION TO PROBLEM

[0012] To address the above-discussed issues, according to the present disclosure, a method performed by a user equipment (UE) in a wireless communication system can include transmitting, to a base station, capability information about a maximum number of physical downlink shared channels (PDSCHs) that the UE can receive in one slot, receiving, from the base station, configuration information including first information including at least one slot offset value between each of at least one PDSCH reception slot and a transmission slot of a hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook and second information about a maximum number of PDSCHs scheduled in one slot, determining at least one PDSCH reception slot based on the first information, generating a HARQ-ACK codebook including as many HARQ-ACK information pieces as the maximum number of PDSCHs that can be scheduled in each of the determined at least one PDSCH reception slot based on the second information, the HARQ-ACK information being configured for each of the determined at least one PDSCH reception slot, and transmitting, to the base station, the generated HARQ-ACK codebook.

[0013] A method performed by a base station in a wireless communication system can include receiving, from a user equipment (UE), capability information about a maximum number of physical downlink shared channels (PDSCHs) that the UE can receive in one slot, transmitting, to the UE, configuration information including first information including at least one slot offset value between each of at least one PDSCH reception slot and a transmission slot of a hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook and second information about a maximum number of PDSCH occasions scheduled in one slot, and receiving, from the UE, a HARQ-ACK codebook including as many HARQ-ACK information pieces as the maximum number of PDSCHs that can be scheduled in each of at least one PDSCH reception slot determined based on the first information, wherein the HARQ-ACK information can be configured for each of the determined at least one PDSCH reception slot based on the second information.

[0014] A user equipment (UE) in a wireless communication system can include a transceiver; and a controller connected to the transceiver, wherein the controller can be configured to transmit, to a base station, capability information about a maximum number of physical downlink shared channels (PDSCHs) receivable by the UE in one slot, receive, from the base station, configuration information including first information including at least one slot offset value between each of at least one PDSCH reception slot and a transmission slot of a hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook and second information about a maximum number of PDSCHs scheduled in one slot, determine at least one PDSCH reception slot based on the first information, generate the HARQ-ACK codebook including as many pieces of HARQ-ACK information as the maximum number of PDSCHs schedulable in each of the determined at least one PDSCH reception slot, the HARQ-ACK information being configured for each of the determined at least one PDSCH reception slot, based on the second information, and transmit, to the base station, the generated HARQ-ACK codebook.

[0015] A base station in a wireless communication system can include a transceiver; and a controller connected to the transceiver, wherein the controller can be configured to receive, from a user equipment (UE), capability information about a maximum number of physical downlink shared channels (PDSCHs) receivable by the UE in one slot, transmit, to the UE, configuration information including first information including at least one slot offset value between each of at least one PDSCH reception slot and a transmission slot of a hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook and second information about a maximum number of PDSCH occasions scheduled in one slot, and receive, from the UE, the HARQ-ACK codebook including as many pieces of HARQ-ACK information as the maximum number of PDSCHs schedulable in each of at least one PDSCH reception slot determined based on the first information, and the HARQ-ACK information can be configured for each of the determined at least one PDSCH reception slot, based on the second information.

[0016] Advantages of the Invention

[0017] Embodiments set forth herein can provide a device and method capable of efficiently providing services in a mobile communication system. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1A basic structure of a time-frequency domain in a wireless communication system according to an embodiment of the disclosure is shown.

[0019] Figure 2 A structure of a frame, a subframe, and a slot in a wireless communication system according to an embodiment of the disclosure is shown.

[0020] Figure 3 An example of a bandwidth part configuration in a wireless communication system according to an embodiment of the disclosure is shown.

[0021] Figure 4 An example of a control resource set configuration of a downlink control channel in a wireless communication system according to an embodiment of the disclosure is shown.

[0022] Figure 5 A structure of a downlink control channel in a wireless communication system according to an embodiment of the disclosure is shown.

[0023] Figure 6 A method in which a base station and a UE transmit / receive data considering a downlink data channel and a rate matching resource in a wireless communication system according to an embodiment of the disclosure is shown.

[0024] Figure 7 An example of a frequency domain resource allocation regarding a physical downlink shared channel (PDSCH) in a wireless communication system according to an embodiment of the disclosure is shown.

[0025] Figure 8 An example of a time domain resource allocation regarding a PDSCH in a wireless communication system according to an embodiment of the disclosure is shown.

[0026] Figure 9 An example of a time domain resource allocation according to a subcarrier spacing regarding a data channel and a control channel in a wireless communication system according to an embodiment of the disclosure is shown.

[0027] Figure 10 A radio protocol structure of a base station and a UE in a single cell, carrier aggregation, and dual connectivity scenarios according to an embodiment of the disclosure is shown.

[0028] Figure 11a , Figure 11b and Figure 11c A type 1 HARQ-ACK codebook for transmitting a HARQ-ACK of a PDSCH according to an embodiment of the disclosure is shown.

[0029] Figure 12a and Figure 12b A generation of a HARQ-ACK codebook according to a UE capability according to an embodiment of the disclosure is shown.

[0030] Figure 13 ​A case in which a UE according to an embodiment of the disclosure receives two or more PDSCHs having the same index in one slot is shown.

[0031] Figure 14 A change of a HARQ-ACK codebook according to a maximum number of PDSCHs to be processed in one slot according to an embodiment of the disclosure is shown.

[0032] Figure 15 is a flowchart of generating a HARQ-ACK codebook according to an embodiment of the disclosure.

[0033] Figure 16 is a flowchart of selecting a HARQ-ACK codebook type according to an embodiment of the disclosure.

[0034] Figure 17 A structure of a UE in a wireless communication system according to an embodiment of the disclosure is shown.

[0035] Figure 18 A structure of a base station in a wireless communication system according to an embodiment of the disclosure is shown. DETAILED DESCRIPTION

[0036] To meet the demand for wireless data traffic having increased since deployment of 4G communication systems, efforts have been made to develop an improved 5G or pre-5G communication system. Therefore, the 5G or pre-5G communication system is also called a 'Beyond 4G Network' or a 'Post LTE System'. The 5G communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 60GHz bands, so as to accomplish higher data rates. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive MIMO, Full Dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed with 5G communication systems. In addition, the developments for the techniques, such as the coordinated multi-points (CoMP), interference mitigation, and the cloud radio access network (Cloud-RAN) are under way. In the 5G system, the development for the technology for the advanced coding modulation of an advanced coding modulation (ACM), a filter bank multi carrier (FBMC), a non-orthogonal multiple access (NOMA), and a sparse code multiple access (SCMA) is under way.

[0037] The Internet, which is a human centered connectivity network where humans generate and consume information, is now evolving to the Internet of Things (IoT) where distributed entities, such as things, exchange and process information without human intervention. The Internet of Everything (IoE), which is a combination of the IoT technology and the Big Data processing technology through connection with a cloud server, has emerged as a new paradigm for the IoT. As technology elements, such as "sensing technology", "wired / wireless communication and network infrastructure", "service interface technology", and "security technology" have been demanded for IoT implementation, a sensor network, a Machine-to-Machine (M2M) communication, Machine Type Communication (MTC), and so forth have been researched. Such an IoT environment can provide intelligent Internet technology (IT) services that create a new value through collection and analysis of data generated from connected things. The IoT can be applied to a variety of fields including smart home, smart building, smart city, smart car or connected cars, smart grid, health care, smart appliances, and advanced medical services through the convergence and combination of existing information technology (IT) and various industrial applications.

[0038] In line with this, various attempts have been made to apply 5G communication systems (5th-Generation communication system or New Radio (NR)) to IoT networks. For example, technologies such as a sensor network, Machine Type Communication (MTC), and Machine-to-Machine (M2M) communication can be implemented by beamforming, MIMO, and array antennas techniques as 5G communication techniques. Application of a cloud Radio Access Network (cloud RAN) as the above-described Big Data processing technology can also be considered as an example of convergence between the 5G technology and the IoT technology.

[0039] Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings.

[0040] In describing embodiments, descriptions related to technical contents well-known in the related art and not directly associated with the present disclosure will be omitted. Such omission of unnecessary descriptions is intended to prevent obscuring the main idea of the present disclosure and to convey the main idea more clearly.

[0041] For the same reason, in the drawings, some elements can be exaggerated, omitted, or schematically illustrated. Also, the size of each element does not completely reflect its actual size. The same reference numbers are assigned to the same or corresponding elements in the respective drawings.

[0042] The advantages and features of the present disclosure and a method of achieving them will be apparent based on the embodiments described below in detail in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments set forth below, but can be implemented in various different forms. The following embodiments are provided only to completely disclose the present disclosure and to inform those skilled in the art of the scope of the present disclosure, and the present disclosure is defined only by the scope of the claims attached hereto. Throughout the specification, like or similar elements are indicated by like or similar reference numerals. Also, in describing the present disclosure, detailed descriptions of known functions or configurations incorporated herein will be omitted when it is determined that such detailed descriptions can unnecessarily obscure the subject matter of the present disclosure. The terms to be described below are terms defined in consideration of functions in the present disclosure, and can vary according to users, user's intentions, or habits. Therefore, the definition of the terms should be made based on the content of the entire specification.

[0043] In the following description, a base station is an entity that allocates resources to a terminal, and can be at least one of a gNode B, an eNode B, a Node B, a base station (BS), a radio access unit, a base station controller, and a node on a network. A terminal can include a user equipment (UE), a mobile station (MS), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In the present disclosure, "downlink (DL)" refers to a radio link via which a base station transmits a signal to a terminal, and "uplink (UL)" refers to a radio link via which a terminal transmits a signal to a base station. Also, in the following description, long-term evolution (LTE), LTE-advanced (LTE-A), or a 5th generation (5G) system can be described by way of example, but embodiments of the present disclosure can also be applied to other communication systems having a similar technical background or channel type. Examples of such communication systems can include 5th generation mobile communication technology (5G, new radio, and NR) developed beyond LTE-A, and in the following description, "5G" can be a concept covering existing LTE, LTE-A, and other similar services. In addition, based on the determination of those skilled in the art, the present disclosure can also be applied to other communication systems with some modifications without departing from the scope of the present disclosure.

[0044] In this document, it will be understood that each box in a flowchart illustration and combinations of boxes in a flowchart illustration can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more flowchart boxes. These computer program instructions can also be stored in a computer-usable or computer-readable storage medium that can instruct the computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-usable or computer-readable storage medium produce an article of writing including instruction means for implementing the functions specified in one or more flowchart boxes. The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus, thereby producing a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowchart boxes.

[0045] Furthermore, each box in the flowchart diagram may represent a module, segment, or portion of code, which includes one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative implementations, the functions mentioned in the boxes may occur out of order. For example, depending on the functions involved, two boxes shown consecutively may actually execute substantially concurrently, or the boxes may sometimes execute in reverse order.

[0046] As used in the embodiments of the present disclosure, the term "unit" refers to a software element or a hardware element such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and can perform some functions. However, the "unit" does not always have a meaning limited to software or hardware. The "unit" can be constructed as a storage medium that is addressable or as one or more processors that execute a program. Therefore, the "unit" includes, for example, a software element, an object-oriented software element, a class element or a task element, a process, a function, a property, a procedure, a subroutine, a program code segment, a driver, firmware, a microcode, a circuit, a data, a database, a data structure, a table, an array, and a parameter. Elements and functions provided by the "unit" can be combined with one or more other elements or "units" to be implemented as a smaller number of elements or "units", or divided into a larger number of elements or "units". Also, the elements and "units" can be implemented to reproduce one or more CPUs within a device or a secure multimedia card. Also, the "unit" in the embodiments can include one or more processors.

[0047] Wireless communication systems are developing into broadband wireless communication systems to provide high-speed and high-quality packet data services as well as typical voice-based services using communication standards such as 3GPP's high-speed packet access (HSPA), LTE (long term evolution or evolved universal terrestrial radio access (E-UTRA)), LTE-A (LTE-Advanced), LTE-Pro, 3GPP2's high-rate packet data (HRPD), ultra-mobile broadband (UMB), IEEE 802.16e, etc.

[0048] As a typical example of a broadband wireless communication system, an LTE system employs an orthogonal frequency division multiplexing (OFDM) scheme in a downlink (DL) and employs a single carrier frequency division multiple access (SC-FDMA) scheme in an uplink (UL). The uplink refers to a radio link via which a user equipment (UE) or a mobile station (MS) transmits data or a control signal to a base station (BS, eNode B, or gNode B), and the downlink refers to a radio link via which the base station transmits data or a control signal to the UE. The above-described multiple access scheme can separate data or control information of respective users by allocating and operating time-frequency resources for transmitting data or control information for each user so as to avoid mutual overlap, i.e., so as to establish orthogonality.

[0049] Since a 5G communication system, which is a post-LTE communication system, must freely reflect various requirements of users, service providers, etc., services satisfying various requirements must be supported. Services considered in the 5G communication system include enhanced mobile broadband (eMBB) communication, massive machine type communication (mMTC), ultra-reliability low-latency communication (URLLC), etc.

[0050] The eMBB aims to provide a higher data rate than that supported by the existing LTE, LTE-A, or LTE-Pro. For example, in the 5G communication system, the eMBB must provide a peak data rate of 20 Gbps in a downlink and a peak data rate of 10 Gbps in an uplink for a single base station. In addition, the 5G communication system must provide an increased user-perceived data rate, as well as a maximum data rate, to the UE. In order to meet such requirements, transmission / reception techniques including a further enhanced multiple input multiple output (MIMO) transmission technique are required to be improved. In addition, a frequency bandwidth greater than 20 MHz can be used in a frequency band of 3 to 6 GHz or 6 GHz or above to obtain the data rate required for the 5G communication system, instead of using a transmission bandwidth of at most 20 MHz in a 2 GHz band used in LTE to transmit a signal.

[0051] In addition, the mMTC is being considered to support application services such as the Internet of Things (IoT) in the 5G communication system. In order to efficiently provide the Internet of Things, the mMTC has requirements such as supporting connection of a large number of UEs in a cell, enhanced coverage of a UE, improvement of a battery time, reduction of a cost of a UE, etc. Since the Internet of Things provides a communication function while being provided to various sensors and various devices, it must support a large number of UEs (e.g., 1,000,000 UEs / km 2In addition, the UE supporting mMTC can require wider coverage than other services provided by the 5G communication system because the UE can be located in a shadow area (such as a basement of a building) that is not covered by a cell due to the nature of the service. The UE supporting mMTC must be configured to be inexpensive and can require a very long battery life, such as 10 to 15 years, because it is difficult to frequently replace the battery of the UE.

[0052] Finally, URLLC is a mission-critical wireless communication service based on a cell. For example, URLLC can be used for services such as remote control of robots or machines, industrial automation, unmanned aerial vehicles, remote healthcare, and emergency alerts. Therefore, URLLC must provide communication with ultra-low latency and ultra-high reliability. For example, a service supporting URLLC must satisfy an air interface latency of less than 0.5 ms, and also requires a packet error rate of 10 -5 or less. However, the above-described mMTC, URLLC, and eMBB are merely examples of different types of services, and the types of services to which the disclosure is applied are not limited to the above-described examples.

[0053] The three services in 5G, i.e., eMBB, URLLC, and mMTC, can be multiplexed and transmitted in a single system. In this case, different transmission / reception techniques and transmission / reception parameters can be used between services in order to satisfy different requirements of the corresponding services. Of course, 5G is not limited to the above-described three services.

[0054] [NR time-frequency resources]

[0055] Hereinafter, the frame structure of the 5G system will be described in more detail with reference to the accompanying drawings.

[0056] Figure 1 A basic structure of a time-frequency domain in a 5G system, which is a radio resource domain for transmitting data or a control channel, is illustrated.

[0057] In Figure 1 , the horizontal axis represents the time domain, and the vertical axis represents the frequency domain. A basic unit of a resource in the time-frequency domain is a resource element (RE) 101, which can be defined as one orthogonal frequency-division multiplexing (OFDM) symbol 102 on the time axis and one subcarrier 103 on the frequency axis. In the frequency domain, (e.g., 12) consecutive REs can constitute one resource block (RB) 104.

[0058] Figure 2 The structure of a frame, a subframe, and a slot in a wireless communication system according to an embodiment of the disclosure is illustrated.

[0059] Figure 2An example of the structure of a frame 200, a subframe 201, and a slot 202 is shown in FIG. 2. One subframe 201 can be defined as 1 ms, and thus one frame 200 can include a total of ten subframes 201. One slot 202 or 203 can be defined as 14 OFDM symbols (i.e., the number of symbols per slot = 14). One subframe 201 can include one or more slots 202 and 203, and the number of slots 202 and 203 per subframe 201 can vary depending on the configuration value μ 204 or 205 of the subcarrier spacing. Figure 2 An example in FIG. 2 shows the case where the subcarrier spacing configuration value is μ = 0 (204), and the case where μ = 1 (205). In the case of μ = 0 (204), one subframe 201 can include one slot 202, and in the case of μ = 1 (205), one subframe 201 can include two slots 203. That is, the number of slots per subframe may differ depending on the subcarrier spacing configuration value μ, and the number of slots per frame may accordingly differ. and may be defined according to each subcarrier spacing configuration μ, as shown in Table 1 below.

[0060] [Table 1]

[0061]

[0062] [bandwidth part (BWP)]

[0063] Next, the bandwidth part (BWP) configuration in a 5G communication system will be described in detail with reference to the accompanying drawings.

[0064] Figure 3 An example of the bandwidth part configuration in a wireless communication system according to an embodiment of the disclosure is shown.

[0065] Figure 3 An example is shown in which a UE bandwidth 300 is configured to include two bandwidth parts, i.e., a bandwidth part #1 (BWP #1) 301 and a bandwidth part #2 (BWP #2) 302. The base station can configure one or more bandwidth parts for the UE, and can configure the following pieces of information with respect to each bandwidth part, as given in Table 2 below.

[0066] [Table 2]

[0067]

[0068] It is apparent that the above examples are not restrictive and various parameters related to bandwidth parts can be configured for the UE in addition to the above-described configuration information. The base station can transmit the configuration information to the UE through upper layer signaling (e.g., radio resource control (RRC) signaling). At least one of one configured bandwidth part or a plurality of configured bandwidth parts can be activated. Whether a configured bandwidth part is activated can be semi-statically transmitted from the base station to the UE through RRC signaling or dynamically transmitted from the base station to the UE through downlink control information (DCI).

[0069] According to some embodiments, before radio resource control (RRC) connection, an initial bandwidth part (BWP) for initial access can be configured for the UE by the base station through a master information block (MIB). More specifically, the UE can receive configuration information about a control resource set (CORESET) and a search space through the MIB in an initial access step, which can be used to transmit a PDCCH (physical downlink control channel) for receiving system information (the system information can correspond to remaining system information (RMSI) or system information block 1 (SIB1) necessary for initial access). Each of the control resource set and the search space configured through the MIB can be considered as identification (ID) 0. The base station can notify the UE of configuration information about control region #0 through the MIB, such as frequency allocation information, time allocation information, and a set of basic parameters. In addition, the base station can notify the UE of configuration information about a monitoring period and occasion for the control resource set #0 through the MIB, i.e., configuration information about the search space #0. The UE can consider a frequency domain configured through the control resource set #0 acquired from the MIB as an initial bandwidth part for initial access. The ID of the initial bandwidth part can be considered as 0.

[0070] The bandwidth part-related configuration supported by the 5G system can be used for various purposes.

[0071] According to embodiments, if the bandwidth supported by the UE is less than the system bandwidth, this can be supported through bandwidth part configuration. For example, the base station can configure the frequency location of the bandwidth part for the UE (configuration information 2) so that the UE can transmit / receive data at a specific frequency location within the system bandwidth.

[0072] In addition, according to some embodiments, for the purpose of supporting different numerologies, the base station can configure a plurality of bandwidth parts for the UE. For example, for the purpose of supporting data transmission / reception of a UE using both 15 kHz subcarrier spacing and 30 kHz subcarrier spacing, two bandwidth parts can be configured as 15 kHz subcarrier spacing and 30 kHz subcarrier spacing, respectively. Different bandwidth parts can be subjected to frequency division multiplexing (FDM), and if data is to be transmitted / received in a specific subcarrier spacing, a bandwidth part configured as the corresponding subcarrier spacing can be activated.

[0073] In addition, according to embodiments, for the purpose of reducing power consumed by the UE, the base station can configure a bandwidth part having a different bandwidth size for the UE. For example, if the UE supports a substantially large bandwidth (e.g., 100 MHz) and always transmits / receives data in the corresponding bandwidth, a substantial amount of power consumption can occur. In particular, from the perspective of power consumption, it can be substantially inefficient to monitor a downlink control channel using a large bandwidth of 100 MHz in the absence of traffic. To reduce power consumed by the UE, the base station can configure a bandwidth part of a relatively small bandwidth (e.g., a bandwidth part of 20 MHz) for the UE. In the absence of traffic, the UE can perform a monitoring operation in the 20 MHz bandwidth part, and if data has occurred, can transmit / receive data using a 100 MHz bandwidth part as instructed by the base station.

[0074] In connection with the bandwidth part configuration method, the UE can receive configuration information about an initial bandwidth part through an MIB in an initial access step before being in an RRC connection. More specifically, the UE can have a control resource set (CORESET) configured for a downlink control channel according to an MIB of a physical broadcast channel (PBCH), which can be used to transmit downlink control information (DCI) for scheduling a system information block (SIB). The bandwidth of the control resource set configured by the MIB can be considered as an initial bandwidth part, and the UE can receive a physical downlink shared channel (PDSCH) through which the SIB is transmitted, through the configured initial bandwidth part. The initial bandwidth part can be used not only for the purpose of receiving the SIB, but also for other system information (OSI), paging, random access, etc.

[0075] [Bandwidth part (BWP) change]

[0076] If the UE has one or more bandwidth parts configured for it, the base station can indicate a change (or switch or transition) of the bandwidth part to the UE by using a bandwidth part indicator field within the DCI. As an example, if the current activated bandwidth part of the UE is bandwidth part #1301 in Figure 3 , the base station can indicate bandwidth part #2302 with the bandwidth part indicator within the DCI, and the UE can change the bandwidth part to bandwidth part #2302 indicated by the bandwidth part indicator within the received DCI.

[0077] As described above, the DCI-based bandwidth part change can be indicated by the DCI for scheduling the PDSCH or the PUSCH, and thus, after receiving the bandwidth part change request, the UE needs to be able to receive or transmit the PDSCH or the PUSCH scheduled by the corresponding DCI without any problem in the changed bandwidth part. To this end, a requirement for a delay time (T BWP ) required during the bandwidth part change is specified in the standard, and can be defined in, for example, Table 3.

[0078] [Table 3]

[0079]

[0080] Depending on the capability of the UE, the requirement for the bandwidth part change delay time supports Type 1 or Type 2. The UE can report the supportable bandwidth part change delay time type to the base station.

[0081] If the UE has received the DCI including the bandwidth part change indicator in slot n, the UE can complete the change to the new bandwidth part indicated by the bandwidth part change indicator at no later than the time point of slot n+T BWP , and can transmit / receive the data channel scheduled by the corresponding DCI in the changed new bandwidth part according to the requirement described above regarding the bandwidth part change delay time. If the base station wants to schedule the data channel by using the new bandwidth part, the base station can determine the time domain resource allocation regarding the data channel based on the bandwidth part change delay time (T BWP ) of the UE. That is, when scheduling the data channel by using the new bandwidth part, the base station can schedule the corresponding data channel after the bandwidth part change delay time in connection with the method for determining the time domain resource allocation regarding the data channel. Accordingly, the UE can not expect the DCI indicating the bandwidth part change to indicate a slot offset (K0 or K2) value less than the bandwidth part change delay time (T BWP ).

[0082] If the UE has received a DCI (e.g., DCI format 1_1 or 0_1) indicating a bandwidth part change, the UE can not perform transmission or reception during a time interval from a third symbol of a slot for receiving a PDCCH including the corresponding DCI to a start of a slot indicated by a time domain resource allocation indicator field in the corresponding DCI by a slot offset (K0 or K2) value. For example, if the UE has received a DCI indicating a bandwidth part change in slot n, and if a slot offset value indicated by the corresponding DCI is K, the UE can not perform transmission or reception from the third symbol of slot n to a symbol before slot n+K (e.g., the last symbol of slot n+K-1).

[0083] [SS / PBCH block]

[0084] Next, a synchronization signal (SS) / PBCH block in a 5G system will be described.

[0085] The SS / PBCH block can refer to a physical layer channel block including a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a PBCH. Details thereof are as follows.

[0086] - PSS: is a signal that becomes a reference for downlink time / frequency synchronization and provides partial information of a cell ID.

[0087] - SSS: becomes a reference for downlink time / frequency synchronization and provides remaining cell ID information not provided by the PSS. In addition, the SSS can serve as a reference signal for PBCH demodulation of the PBCH.

[0088] - PBCH: provides an MIB, which is mandatory system information necessary for the UE to transmit / receive a data channel and a control channel. The mandatory system information can include search space related control information indicating radio resource mapping information of a control channel, scheduling control information about a separate data channel for transmitting system information, and the like.

[0089] - SS / PBCH block: The SS / PBCH block includes a combination of the PSS, the SSS, and the PBCH. One or more SS / PBCH blocks can be transmitted within a time period of 5 ms, and each transmitted SS / PBCH block can be distinguished by an index.

[0090] A UE can detect a PSS and a SSS in an initial access stage and can decode a PBCH. The UE can acquire an MIB from the PBCH and this can be used to configure a control resource set (CORESET) #0 (which can correspond to a control resource set with a control resource set index of 0). The UE can monitor the control resource set #0 by assuming that a demodulation reference signal (DMRS) transmitted in a selected SS / PBCH block and the control resource set #0 are quasi-co-located (QCL). The UE can receive system information with a downlink control information transmitted in the control resource set #0. The UE can acquire configuration information related to a random access channel (RACH) necessary for initial access from the received system information. The UE can transmit a physical RACH (PRACH) to a base station with consideration of a selected SS / PBCH index, and the base station can acquire information about an SS / PBCH block index selected by the UE upon reception of the PRACH. The base station can know the fact that the UE has selected which block from among the corresponding SS / PBCH blocks and a control resource set #0 associated therewith is monitored.

[0091] [PDCCH: About DCI]

[0092] Next, downlink control information (DCI) in a 5G system will be described in detail.

[0093] In a 5G system, scheduling information about uplink data (or a physical uplink shared channel (PUSCH)) or downlink data (or a physical downlink shared channel (PDSCH)) is included in DCI and is transmitted from a base station to a UE through the DCI. The UE can monitor a fallback DCI format and a non-fallback DCI format for the PUSCH or the PDSCH. The fallback DCI format can include a fixed field predefined between the base station and the UE, and the non-fallback DCI format can include a configurable field.

[0094] The DCI can be subjected to a channel coding and modulation process, and then transmitted through a physical downlink control channel (PDCCH) after the channel coding and modulation process. A cyclic redundancy check (CRC) can be attached to a payload of the DCI message, and the CRC can be scrambled by a radio network temporary identifier (RNTI) corresponding to an identity of the UE. Different RNTIs can be used according to a purpose of the DCI message, for example, UE-specific data transmission, a power control command, or a random access response. That is, the RNTI can not be explicitly transmitted, but can be transmitted while being included in a CRC calculation process. Upon receiving the DCI message transmitted through the PDCCH, the UE can identify the CRC by using the allocated RNTI, and if the CRC identification result is correct, the UE can know that the corresponding message has been transmitted to the UE.

[0095] For example, the DCI for scheduling the PDSCH with respect to system information (SI) can be scrambled by a system information-RNTI (SI-RNTI). The DCI for scheduling the PDSCH with respect to a random access response (RAR) message can be scrambled by a random access (RA)-RNTI. The DCI for scheduling the PDSCH with respect to a paging message can be scrambled by a paging RNTI (P-RNTI). The DCI for notifying a slot format indicator (SFI) can be scrambled by an SFI-RNTI. The DCI for notifying a slot format indicator (SFI) can be scrambled by a slot format indicator-RNTI (SFI-RNTI). The DCI for notifying transmit power control (TPC) can be scrambled by a transmit power control-RNTI (TPC-RNTI). The DCI for scheduling a UE-specific PDSCH or PUSCH can be scrambled by a cell RNTI (C-RNTI).

[0096] The DCI format 0_0 can be used as fallback DCI for scheduling the PUSCH, and in this case, the CRC can be scrambled by the C-RNTI. For example, the DCI format 0_0 in which the CRC is scrambled by the C-RNTI can include the following pieces of information given in Table 4 below.

[0097] [Table 4]

[0098]

[0099] DCI format 0_1 can be used as non-fallback DCI for scheduling PUSCH, and in this case, the CRC can be scrambled by C-RNTI. For example, DCI format 0_1 with CRC scrambled by C-RNTI can include the following pieces of information given in Table 5 below.

[0100] [Table 5]

[0101]

[0102]

[0103]

[0104] DCI format 1_0 can be used as fallback DCI for scheduling PDSCH, and in this case, the CRC can be scrambled by C-RNTI. For example, DCI format 1_0 with CRC scrambled by C-RNTI can include the following pieces of information given in Table 6 below.

[0105] [Table 6]

[0106]

[0107] DCI format 1_1 can be used as non-fallback DCI for scheduling PDSCH, and in this case, the CRC can be scrambled by C-RNTI. For example, DCI format 1_1 with CRC scrambled by C-RNTI can include the following pieces of information given in Table 7 below.

[0108] [Table 7]

[0109]

[0110]

[0111] [PDCCH: CORESET, REG, CCE, and search space]

[0112] Hereinafter, a downlink control channel in a 5G communication system will be described in greater detail with reference to the accompanying drawings.

[0113] Figure 4 An example of a control resource set configuration of a downlink control channel in a wireless communication system according to an embodiment of the disclosure is illustrated. Figure 4 An example of a control resource set (CORESET) for transmitting a downlink control channel in a 5G wireless communication system is illustrated. Figure 4An example is shown in which a UE bandwidth part 410 is configured along a frequency axis and two control resource sets (control resource set #1 420 and control resource set #2 401) are configured within one slot 402 along a time axis. The control resource sets 401 and 402 can be configured in specific frequency resources 410 within the entire UE bandwidth part 403 along the frequency axis. The control resource sets 401 and 402 can each be configured as one or more OFDM symbols along the time domain, and the number of OFDM symbols can be defined as a control resource set duration 404. Referring to Figure 4 In the example shown, control resource set #1 401 is configured to have a control resource set duration corresponding to two symbols, and control resource set #2 402 is configured to have a control resource set duration corresponding to one symbol.

[0114] The control resource set in 5G described above can be configured for a UE by a base station through upper layer signaling (e.g., system information, master information block (MIB), radio resource control (RRC) signaling). The description of configuring a control resource set for a UE means to provide information such as a control resource set identification, a frequency location of the control resource set, and a symbol duration of the control resource set. For example, the control resource set can include the following pieces of information given in Table 8 below.

[0115] [Table 8]

[0116]

[0117]

[0118] In Table 8, the tci-StatesPDCCH (abbreviated as transmission configuration indication (TCI) state) configuration information can include information of one or more SS / PBCH block indices or channel state information reference signal (CSI-RS) indices that are quasi co-located (QCLed) with a DMRS transmitted in the corresponding control resource set.

[0119] Figure 5 A structure of a downlink control channel in a wireless communication system according to an embodiment of the disclosure is shown.

[0120] Figure 5 An example of a basic unit of time and frequency resources constituting a downlink control channel available in 5G is shown. According to Figure 5The basic unit of time and frequency resources constituting a control channel can be referred to as a resource element group (REG) 503, and the REG 503 can be defined by one OFDM symbol 501 along the time axis and one physical resource block (PRB) 502 (i.e., 12 subcarriers) along the frequency axis. The base station can configure a downlink control channel allocation unit by concatenating the REGs 503.

[0121] Assuming that the basic unit of downlink control channel allocation in 5G is a control channel element 504 as shown in FIG. 5A, one CCE 504 can include a plurality of REGs 503. To describe the REG 503 as shown in FIG. 5B, for example, the REG 503 can include 12 REs, and if one CCE 504 includes 6 REGs 503, one CCE 504 can include 72 REs. The downlink control resource set can include a plurality of CCEs 504 once configured, and a specific downlink control channel can be mapped to one or more CCEs 504 and then transmitted according to an aggregation level (AL) in the control resource set. The CCEs 504 in the control resource set are distinguished by numbering, and the numbering of the CCEs 504 can be allocated according to a logical mapping scheme. Figure 5 Figure 5

[0122] Figure 5 The basic unit of the downlink control channel (i.e., the REG 503) as shown in FIG. 5B can include both REs to which DCI is mapped and an area to which a reference signal (DMRS 505) for decoding the DCI is mapped. As shown in FIG. 5C, three DRMS 503 can be transmitted within one REG 505. According to an aggregation level (AL), the number of CCEs necessary to transmit a PDCCH can be 1, 2, 4, 8, or 16, and different numbers of CCEs can be used to implement link adaptation of a downlink control channel. For example, in the case of AL=L, one downlink control channel can be transmitted through L CCEs. The UE needs to detect a signal without information about the downlink control channel, and thus a search space indicating a set of CCEs has been defined to perform blind decoding. The search space is a set of downlink control channel candidates including CCEs that the UE needs to attempt to decode at a given AL, and since 1, 2, 4, 8, or 16 CCEs can constitute a bundle at various ALs, the UE can have a plurality of search spaces. The search space set can be defined as a set of search spaces at all configured aggregation levels. Figure 5

[0123] ​​​The search space can be categorized into a common search space and a UE-specific search space. A group of UEs or all UEs can search the common search space of the PDCCH to receive cell common control information, such as dynamic scheduling or paging messages regarding system information. For example, searching the common search space of the PDCCH can be used to receive PDSCH scheduling allocation information for transmitting SIBs, including cell operator information. In the case of the common search space, a group of UEs or all UEs need to receive the PDCCH, and therefore the common search space can be defined as a predetermined set of CCEs. Searching the UE-specific search space of the PDCCH can be used to receive scheduling allocation information regarding UE-specific PDSCH or PUSCH. The UE-specific search space can be defined by the UE specifically as a function of various system parameters and the UE's identifier.

[0124] In 5G systems, parameters regarding the PDCCH search space can be configured for the UE by the base station via upper-layer signaling (e.g., SIB, MIB, or RRC signaling). For example, the base station can provide the UE with configurations such as the number of PDCCH candidates under each aggregation level L, the monitoring period for the search space, the monitoring timing for each symbol in a time slot within the search space, the search space type (common search space or UE-specific search space), the combination of RNTI and DCI formats to be monitored in the corresponding search space, and the control resource set index used for monitoring the search space. For instance, the parameters of the PDCCH search space may include several pieces of information as given in Table 9 below.

[0125] [Table 9]

[0126]

[0127]

[0128]

[0129] Based on the configuration information, the base station can configure one or more search space sets for the UE. According to some embodiments, the base station can configure search space set 1 and search space set 2 for the UE, and can configure DCI format A scrambled by X-RNTI to be monitored in the common search space in search space set 1, and can configure DCI format B scrambled by Y-RNTI to be monitored in the UE-specific search space in search space set 2.

[0130] Depending on the configuration information, one or more search space sets can exist in a public search space or a UE-specific search space. For example, search space set #1 and search space set #2 can be configured as a public search space, and search space set #3 and search space set #4 can be configured as UE-specific search spaces.

[0131] The combinations of DCI formats and RNTIs given below can be monitored in the common search space. Obviously, the examples given below are not limiting.

[0132] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS (Configured Scheduling) -RNTI, SP (Semi-Persistent) -CSI-RNTI, RA-RNTI, TC (Temporary Cell) -RNTI, P-RNTI, SI-RNTI

[0133] - DCI format 2_0 with CRC scrambled by SFI-RNTI

[0134] - DCI format 2_1 with CRC scrambled by INT (Interruption) -RNTI

[0135] - DCI format 2_2 with CRC scrambled by TPC-PUSCH-RNTI, TPC-PUCCH-RNTI

[0136] - DCI format 2_3 with CRC scrambled by TPC-SRS-RNTI

[0137] The combinations of DCI formats and RNTIs given below can be monitored in the UE-specific search space. Obviously, the examples given below are not limiting.

[0138] - DCI format 0_0 / 1_0 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0139] - DCI format 1_0 / 1_1 with CRC scrambled by C-RNTI, CS-RNTI, TC-RNTI

[0140] The RNTIs listed can follow the definitions and uses given below.

[0141] Cell RNTI (C-RNTI): used to schedule UE-specific PDSCH

[0142] Temporary Cell RNTI (TC-RNTI): used to schedule UE-specific PDSCH

[0143] Configured Scheduling RNTI (CS-RNTI): used to schedule semi-statically configured UE-specific PDSCH

[0144] Random Access RNTI (RA-RNTI): used to schedule PDSCH in the random access procedure

[0145] Paging RNTI (P-RNTI): used for scheduling PDSCH in which a paging is transmitted

[0146] System Information RNTI (SI-RNTI): used for scheduling PDSCH in which system information is transmitted

[0147] Interruption RNTI (INT-RNTI): used for indicating whether a PDSCH is punctured or not

[0148] RNTI for transmit power control of PUSCH (TPC-PUSCH-RNTI): used for indicating a power control command for PUSCH

[0149] RNTI for transmit power control of PUCCH (TPC-PUCCH-RNTI): used for indicating a power control command for PUCCH

[0150] RNTI for transmit power control of SRS (TPC-SRS-RNTI): used for indicating a power control command for SRS

[0151] For example, the above-listed DCI formats can follow the definitions given in the following Table 10.

[0152] [Table 10]

[0153]

[0154] In the 5G system, the search space at the aggregation level L related to the CORESET p and the search space set s can be expressed by the following Equation 1.

[0155] [Equation 1]

[0156]

[0157] -L: aggregation level

[0158] - : carrier index

[0159] - : total number of CCEs present in the control resource set p

[0160] - : slot index

[0161] - : number of PDCCH candidates at the aggregation level L

[0162] - = 0, …, -1: PDCCH candidate index under aggregation level L

[0163] - = 0,... -1

[0164] - , , for , ; for , ; for , ,

[0165] - : UE identity

[0166] In the case of common search space, the value can correspond to 0.

[0167] In the case of UE-specific search space, the value can correspond to a value changed by the identity of the UE (C-RNTI or ID configured for the UE by the base station) and the time index.

[0168] In the 5G system, a plurality of search space sets can be configured by different parameters (for example, parameters in Table 9), and accordingly a set of search space sets that the UE monitors at each time point can be different. For example, if search space set #1 is configured with an X slot period, if search space set #2 is configured with a Y slot period, and if X and Y are different, the UE can monitor both search space set #1 and search space set #2 in a specific slot, and can monitor one of search space set #1 and search space set #2 in another specific slot.

[0169] [PDCCH: BD / CCE limit]

[0170] If there are a plurality of search space sets configured for the UE, the following conditions can be considered in connection with a method for determining a search space set to be monitored by the UE.

[0171] If the value of "monitoringCapabilityConfig-r16" (higher layer signaling) has been configured for the UE to be "r15monitoringcapability", the UE defines the maximum value on the number of PDCCH candidates that can be monitored and the number of CCEs that constitute the entire search space (as used herein, the entire search space refers to the entire set of CCEs corresponding to the union of multiple search space sets) per slot. If the value of "monitoringCapabilityConfig-r16" has been configured to be "r16monitoringcapability", the UE defines the maximum value on the number of PDCCH candidates that can be monitored and the number of CCEs that constitute the entire search space (as used herein, the entire search space refers to the entire set of CCEs corresponding to the union of multiple search space sets) per span.

[0172] [Condition 1: Maximum number of PDCCH candidates is limited]

[0173] According to the above-mentioned higher layer signaling configuration value, if the maximum number of PDCCH candidates Mμ that the UE can monitor is defined with reference to a slot in a cell configured to have a subcarrier spacing of 15·2μ kHz, the maximum number of PDCCH candidates Mμ that the UE can monitor can follow Table 11 given below, and if the maximum number of PDCCH candidates Mμ that the UE can monitor is defined with reference to a span, the maximum number of PDCCH candidates Mμ that the UE can monitor can follow Table 12 given below.

[0174] [Table 11]

[0175]

[0176] [Table 12]

[0177]

[0178] [Condition 2: Maximum number of CCEs is limited]

[0179] According to the above-mentioned higher layer signaling configuration value, if the maximum number of CCEs Cμ that constitute the entire search space (as used herein, the entire search space refers to the entire set of CCEs corresponding to the union of multiple search space sets) is defined with reference to a slot in a cell configured to have a subcarrier spacing of 15·2μ kHz, the maximum number of CCEs Cμ that constitute the entire search space can follow Table 13 given below, and if the maximum number of CCEs Cμ that constitute the entire search space is defined with reference to a span, the maximum number of CCEs Cμ that constitute the entire search space can follow Table 14 given below.

[0180] [Table 13]

[0181]

[0182] [Table 14]

[0183]

[0184] For convenience of description, a case where both the above-described Condition 1 and Condition 2 are satisfied at a specific time point can be defined as "Condition A". Thus, a description that Condition A is not satisfied can mean that at least one of the above-described Condition 1 and 2 is not satisfied.

[0185] [PDCCH: Overbooking]

[0186] According to the configuration of the search space set of the base station, a case where Condition A is not satisfied can occur at a specific time point. If Condition A is not satisfied at a specific time point, the UE can select and monitor only some of the search space sets configured to satisfy Condition A at the corresponding time point, and the base station can transmit a PDCCH to the selected search space set.

[0187] A method for selecting some search spaces from all configured search space sets can follow the method given below.

[0188] If Condition A regarding the PDCCH is not satisfied at a specific time point (slot), the UE (or the base station) can select a search space set having a search space type configured as a common search space in preference to a search space set configured as a UE-specific search space among the search space sets existing at the corresponding time point.

[0189] If all search space sets configured as common search spaces have been selected (i.e., if Condition A is satisfied even after all search spaces configured as common search spaces have been selected), the UE (or the base station) can select a search space set configured as a UE-specific search space. If there are multiple search space sets configured as UE-specific search spaces, a search space set having a lower search space set index can have a higher priority. In consideration of the priority, the UE (or the base station) can select a UE-specific search space set as long as Condition A is satisfied.

[0190] [Regarding rate matching / puncturing]

[0191] Hereinafter, the rate matching operation and the puncturing operation will be described in detail.

[0192] If the time and frequency resources A for transmitting the symbol sequence A overlap with the time and frequency resources B, a rate matching or puncturing operation can be considered as an operation of transmitting / receiving the channel A in consideration of the resources C (the region where the resources A and the resources B overlap). The specific operation can follow the description below.

[0193] Rate matching operation

[0194] The base station can transmit the channel A after mapping the channel A to the remaining resource region of the entire resources A except for the resources C (the region overlapping with the resources B), where the entire resources A will be used to transmit the symbol sequence A to the UE. For example, if the symbol sequence A is configured as {symbol #1, symbol #2, symbol #3, symbol #4}, if the resources A are {resource #1, resource #2, resource #3, resource #4}, and if the resources B are {resource #3, resource #5}, the UE can receive the symbol sequence A based on the assumption that the symbol sequence A has been mapped to the remaining resources {resource #1, resource #2, resource #4} of the resources A except for {resource #3} (corresponding to the resources C) in succession. As a result, the base station can transmit the symbol sequence {symbol #1, symbol #2, symbol #3} after mapping the symbol sequence {symbol #1, symbol #2, symbol #3} to {resource #1, resource #2, resource #4}, respectively.

[0195] The UE can evaluate the resources A and the resources B according to the scheduling information about the symbol sequence A from the base station, thereby evaluating the resources C (the region where the resources A and the resources B overlap). The UE can receive the symbol sequence A based on the assumption that the symbol sequence A has been mapped and transmitted in the remaining region of the entire resources A except for the resources C. For example, if the symbol sequence A is configured as {symbol #1, symbol #2, symbol #3, symbol #4}, if the resources A are {resource #1, resource #2, resource #3, resource #4}, and if the resources B are {resource #3, resource #5}, the UE can receive the symbol sequence A based on the assumption that the symbol sequence A has been mapped to the remaining resources {resource #1, resource #2, resource #4} of the resources A except for {resource #3} (corresponding to the resources C) in succession. As a result, the UE can perform a series of the following reception operations based on the assumption that the symbol sequence {symbol #1, symbol #2, symbol #3} has been transmitted after being mapped to {resource #1, resource #2, resource #4}, respectively.

[0196] Puncturing operation

[0197] If there is a resource C (a region overlapping with the resource B) in the entire resource A to be used for transmitting the symbol sequence A to the UE, the base station can map the symbol sequence A to the entire resource A, but can not perform transmission in the resource region corresponding to the resource C, and can perform transmission only for the remaining resource regions of the resource A except for the resource C. For example, if the symbol sequence A is configured as {symbol #1, symbol #2, symbol #3, symbol #4}, the resource A is {resource #1, resource #2, resource #3, resource #4}, and the resource B is {resource #3, resource #5}, the base station can map the symbol sequence A {symbol #1, symbol #2, symbol #3, symbol #4} to the resource A {resource #1, resource #2, resource #3, resource #4}, respectively, can transmit only the symbol sequence {symbol #1, symbol #2, symbol #4} corresponding to the remaining resources {resource #1, resource #2, resource #4} of the resource A except for {resource #3} (corresponding to the resource C), and can not transmit {symbol #3} mapped to {resource #3} (corresponding to the resource C). As a result, the base station can transmit the symbol sequence {symbol #1, symbol #2, symbol #4} after mapping the symbol sequence {symbol #1, symbol #2, symbol #4} to the resource A {resource #1, resource #2, resource #4}, respectively.

[0198] The UE can evaluate the resource A and the resource B according to the scheduling information about the symbol sequence A from the base station, thereby evaluating the resource C (a region overlapping with the resource A and the resource B). The UE can receive the symbol sequence A based on an assumption that the symbol sequence A has been mapped to the entire resource A but has been transmitted only in the remaining regions of the resource region A except for the resource C. For example, if the symbol sequence A is configured as {symbol #1, symbol #2, symbol #3, symbol #4}, if the resource A is {resource #1, resource #2, resource #3, resource #4}, and if the resource B is {resource #3, resource #5}, the UE can assume that the symbol sequence A {symbol #1, symbol #2, symbol #3, symbol #4} is mapped to the resource A {resource #1, resource #2, resource #3, resource #4}, respectively, but {symbol #3} mapped to {resource #3} (corresponding to the resource C) is not transmitted, and based on an assumption that the symbol sequence {symbol #1, symbol #2, symbol #4} corresponding to the remaining resources {resource #1, resource #2, resource #4} of the resource A except for {resource #3} (corresponding to the resource C) has been mapped and transmitted, the UE can receive the symbol sequence {symbol #1, symbol #2, symbol #4}. As a result, the UE can perform a series of the following reception operations based on an assumption that the symbol sequence {symbol #1, symbol #2, symbol #4} has been transmitted after being mapped to {resource #1, resource #2, resource #4}, respectively.

[0199] Hereinafter, a method for configuring a rate matching resource for the purpose of rate matching in a 5G communication system will be described. Rate matching refers to adjusting the size of a signal in consideration of the amount of resources that can be used to transmit the signal. For example, data channel rate matching can mean that a data channel is not mapped and transmitted for a specific time and frequency resource domain, and the size of data is adjusted accordingly.

[0200] Figure 6 A method in which a base station and a UE transmit / receive data in consideration of a downlink data channel and a rate matching resource in a wireless communication system according to an embodiment of the disclosure is shown.

[0201] Figure 6 A downlink data channel (PDSCH) 601 and a rate matching resource 602 are shown. The base station can configure one or more rate matching resources 602 for the UE through upper layer signaling (e.g., RRC signaling). The rate matching resource 602 configuration information can include time domain resource allocation information 603, frequency domain resource allocation information 604, and periodicity information 605. Hereinafter, a bitmap corresponding to the frequency domain resource allocation information 604 will be referred to as a "first bitmap", a bitmap corresponding to the time domain resource allocation information 603 will be referred to as a "second bitmap", and a bitmap corresponding to the periodicity information 605 will be referred to as a "third bitmap". If all or some of the time and frequency resources of the scheduled PDSCH 601 overlap with the configured rate matching resource 602, the base station can rate match and transmit the PDSCH 602 in the rate matching resource 601 part, and the UE can perform reception and decoding after assuming that the PDSCH 602 has been rate matched in the rate matching resource 601 part.

[0202] The base station can dynamically inform the UE whether to rate match the PDSCH in the configured rate matching resource part by additional configuration through the DCI (for example, corresponding to the "rate matching indicator" within the DCI format described above). Specifically, the base station can select some of the configured rate matching resources and group them into a rate matching resource group, and can indicate to the UE through the DCI whether the PDSCH is rate matched for each rate matching resource group by using a bitmap type. For example, if four rate matching resources RMR#1, RMR#2, RMR#3, and RMR#4 are configured, the base station can configure rate matching groups RMG#1 = {RMR#1, RMR#2}, RMG#2 = {RMR#3, RMR#4}, and can indicate to the UE through a bitmap using two bits within the DCI field whether rate matching occurs in RMG#1 and RMG#2, respectively. For example, in the case of rate matching, the base station can indicate this case by "1", and in the case of not rate matching, the base station can indicate this case by "0".

[0203] 5G supports "RB symbol level" and "RE level" granularity as a method for configuring the above-mentioned rate matching resources for the UE. More specifically, the following configuration method can be followed.

[0204] RB symbol level

[0205] The UE can have a maximum of four RateMatchPatterns configured per bandwidth part through upper layer signaling, and one RateMatchPattern can include the following.

[0206] - can include resources related to reserved resources within a bandwidth part, which have time and frequency resource domains of corresponding reserved resources configured as a combination of RB level bitmap and symbol level bitmap in the frequency domain. The reserved resources can span one or two slots. A time domain pattern (periodicityAndPattern) can be additionally configured, in which the time and frequency domains of the corresponding RB level and symbol level bitmap pair are repeated.

[0207] - can include a resource area corresponding to a time domain pattern configured by a time and frequency domain resource area configured by a CORESET within a bandwidth part and a search space configuration in which the corresponding resource area is repeated.

[0208] RE level

[0209] The UE can have the following configured through upper layer signaling.

[0210] - Configuration information (lte-CRS-ToMatchAround) about REs corresponding to an LTE CRS (cell-specific reference signal or common reference signal) pattern, which can include a port number (nrofCRS-Ports) of the LTE CRS and LTE-CRS-vshift (multiple) values (v-shift), location information (carrierFreqDL) of a center subcarrier of the LTE carrier and a reference point (e.g., reference point A), information (carrierBandwidthDL) of a bandwidth size of the LTE carrier, subframe configuration information (mbsfn-SubframConfigList) corresponding to a multicast-broadcast single-frequency network (MBSFN), etc. The UE can determine the location of the CRS within the NR slot corresponding to the LTE subframe based on the above pieces of information.

[0211] - Configuration information about a resource set corresponding to one or more zero power (ZP) CSI-RSs within a bandwidth part can be included.

[0212] [About LTE CRS rate matching]

[0213] Next, the rate matching procedure about the above LTE CRS will be described in detail. In NR, for coexistence between long term evolution (LTE) and a new RAT (NR) (LTE-NR coexistence), a pattern of a cell-specific reference signal (CRS) of LTE can be configured for an NR UE. More specifically, the CRS pattern can be provided through RRC signaling including at least one parameter inside a ServingCellConfig IE (information element) and a ServingCellConfigCommon IE. Examples of the parameters can include lte-CRS-ToMatchAround, lte-CRS-PatternList1-r16, lte-CRS-PatternList2-r16, crs-RateMatch-PerCORESETPoolIndex-r16, etc.

[0214] Rel-15 NR provides a functionality by which one CRS pattern can be configured per serving cell through a parameter lte-CRS-ToMatchAround. In Rel-16 NR, the above functionality has been extended so that multiple CRS patterns can be configured per serving cell. More specifically, a UE with single-TRP (transmit and receive point) configuration can now have one CRS pattern configured per LTE carrier, and a UE with multi-TRP configuration can now have two CRS patterns configured per LTE carrier. For example, a UE with single-TRP configuration can have up to three CRS patterns configured per serving cell through a parameter lte-CRS-PatternList1-r16. As another example, a UE with multi-TRP configuration can have CRS configured for each TRP. That is, a CRS pattern for TRP1 can be configured through a parameter lte-CRS-PatternList1-r16, and a CRS pattern for TRP2 can be configured through a parameter lte-CRS-PatternList2-r16. If two TRPs are configured as above, it is determined through a parameter crs-RateMatch-PerCORESETPoolIndex-r16 whether to apply CRS patterns of both TRP1 and TRP2 to a specific physical downlink shared channel (PDSCH) or to apply only a CRS pattern for one TRP, where if the parameter crs-RateMatch-PerCORESETPoolIndex-r16 is configured as “enabled”, only the CRS pattern for one TRP is applied, and in other cases, both CRS patterns for both TRPs are applied.

[0215] Table 15 shows a ServingCellConfig IE including a CRS pattern, and Table 16 shows a RateMatchPatternLTE-CRS IE including at least one parameter regarding a CRS pattern.

[0216] [Table 15]

[0217]

[0218]

[0219] [Table 16]

[0220]

[0221] [PDSCH: Regarding frequency resource allocation]

[0222] Figure 7An example of frequency domain resource allocation on a PDSCH in a wireless communication system according to an embodiment of the disclosure is shown.

[0223] Figure 7 Three frequency domain resource allocation methods that can be configured by an upper layer in an NR wireless communication system, Type 0 700, Type 1 705, and dynamic switching 710, are shown.

[0224] Reference Figure 7 In the case where the UE is configured to use only resource type 0 by higher layer signaling (700), partial downlink control information (DCI) for allocating a PDSCH to the UE includes a bitmap including N RBG bits. The conditions for this will be described again later. As used herein, N RBG refers to the number of resource block groups (RBGs) determined according to the BWP size indicated by the BWP indicator and the upper layer parameter rbg-Size, as shown in Table 17 below, and data is transmitted in the RBGs indicated as "1" by the bitmap.

[0225] [Table 17]

[0226]

[0227] In the case where the UE is configured to use only resource type 1 by higher layer signaling (705), partial DCI includes frequency domain resource allocation information including bits. The conditions for this will be described again later. By this, the base station can configure a starting VRB 720 and the length of the frequency domain resources allocated continuously therefrom 725.

[0228] In the case where the UE is configured to use both resource type 0 and resource type 1 by higher layer signaling (710), partial DCI for allocating a PDSCH to the corresponding UE includes frequency domain resource allocation information including as many bits as the larger value between the payload for configuring resource type 0 735 and the payload for configuring resource type 1 720 and 725. The conditions for this will be described again later. One bit can be added to the frontmost part (MSB) of the frequency domain resource allocation information within the DCI, and if the bit has a value of "0", the use of resource type 0 can be indicated, and if the bit has a value of "1", the use of resource type 1 can be indicated.

[0229] [PDSCH / PUSCH: on time resource allocation]

[0230] Hereinafter, a time domain resource allocation method on a data channel in a next-generation mobile communication system (5G or NR system) will be described.

[0231] A base station can configure a UE with a table on time domain resource allocation information for a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH) through upper layer signaling (e.g., RRC signaling). A table including up to maxNrofDL-Allocations=16 entries can be configured for a PDSCH, and a table including up to maxNrofUL-Allocations=16 entries can be configured for a PUSCH. In an embodiment, the time domain resource allocation information can include a PDCCH-to-PDSCH slot timing (e.g., corresponding to a time interval in units of slots between a time point at which a PDCCH is received and a time point at which a PDSCH scheduled by the received PDCCH is transmitted; denoted as K0), a PDCCH-to-PUSCH slot timing (e.g., corresponding to a time interval in units of slots between a time point at which a PDCCH is received and a time point at which a PUSCH scheduled by the received PDCCH is transmitted; hereinafter, denoted as K2), information on a position and length of a starting symbol through which a PDSCH or a PUSCH is scheduled within a slot, a mapping type of the PDSCH or the PUSCH, etc. For example, information such as in Table 18 or Table 19 below can be transmitted from the base station to the UE.

[0232] [Table 18]

[0233]

[0234] [Table 19]

[0235]

[0236] A base station can inform a UE of one of the above-described entries of the table on time domain resource allocation information through L1 signaling (e.g., DCI). For example, this can be indicated via a "time domain resource allocation" field within the DCI. The UE can acquire time domain resource allocation information for a PDSCH or a PUSCH based on the DCI acquired from the base station.

[0237] Figure 8 An example of time domain resource allocation for a PDSCH in a wireless communication system according to an embodiment of the disclosure is illustrated.

[0238] Reference Figure 8 , the UE can acquire a subcarrier spacing (SCS) (μ PDSCH , μ PDCCH), a scheduling offset (K0) value, and an OFDM symbol start position 800 and length 805 within a slot dynamically indicated by DCI to indicate the time domain position of PDSCH resources.

[0239] Figure 9 An example of time domain resource allocation according to subcarrier spacing for data and control channels in a wireless communication system according to embodiments of the disclosure is shown.

[0240] Reference Figure 9 If the data and control channels have the same subcarrier spacing (900, μ PDSCH =μ PDCCH ), the slot number for data and the slot number for control are the same, and the base station and the UE can accordingly generate a scheduling offset consistent with a predetermined slot offset K0. Conversely, if the data and control channels have different subcarrier spacing (905, μ PDSCH ≠ μ PDCCH ), the slot number for data and the slot number for control are different, and the base station and the UE can accordingly generate a scheduling offset consistent with a predetermined slot offset K0 of the subcarrier spacing of the reference PDCCH.

[0241] [PUSCH: Transmission Scheme]

[0242] Next, the PUSCH transmission scheduling scheme will be described. PUSCH transmission can be dynamically scheduled by UL grant within DCI, or operated by configured grant type 1 or type 2 means. Dynamic scheduling indication for PUSCH transmission can be made by DCI format 0_0 or 0_1.

[0243] Configured grant Type 1 PUSCH transmission can be semi-statically configured by receiving configuredGrantConfig including rrc-ConfiguredUplinkGrant in Table 16 via upper layer signaling without receiving UL grant within DCI. Configured grant Type 2 PUSCH transmission can be semi-persistently scheduled by UL grant within DCI after receiving configuredGrantConfig not including rrc-ConfiguredUplinkGrant in Table 16 via upper layer signaling. If PUSCH transmission is operated by configured grant, parameters applied to PUSCH transmission are applied by configuredGrantConfig (upper layer signaling) in Table 16, but dataScramblingIdentityPUSCH, txConfig, codebookSubset, maxRank, and scaling to UCI-OnPUSCH provided by pusch-Config (upper layer signaling) in Table 17 are excluded. If transformPrecoder is provided within configuredGrantConfig (upper layer signaling) in Table 20, UE applies tp-pi2BPSK within pusch-Config in Table 21 to PUSCH transmission operated by configured grant.

[0244] [table 20]

[0245]

[0246]

[0247] Next, a PUSCH transmission method will be described. The DMRS antenna port for PUSCH transmission is the same as the antenna port for SRS transmission. According to whether the value of txConfig within pusch-Config (which is upper layer signaling) in Table 21 is “codebook” or “nonCodebook”, PUSCH transmission can follow a codebook-based transmission method and a non-codebook-based transmission method.

[0248] As described above, a PUSCH transmission can be dynamically scheduled by DCI format 0_0 or 0_1 and can be semi-statically configured by a configured grant. Upon receiving an indication on scheduling of a PUSCH transmission by DCI format 0_0, a UE performs beam configuration for the PUSCH transmission by using pucch-spatialRelationInfoID corresponding to a UE-specific PUCCH resource with the smallest ID within an activated uplink BWP within a serving cell and the PUSCH transmission is based on a single antenna port. Within a BWP for which a PUCCH resource including pucch-spatialRelationInfo is not configured, a UE does not expect scheduling on a PUSCH transmission by DCI format 0_0. If a UE does not have txConfig configured within pusch-Config in Table 21, a UE does not expect scheduling by DCI format 0_1.

[0249] [Table 21]

[0250]

[0251] Next, a codebook-based PUSCH transmission will be described. A codebook-based PUSCH transmission can be dynamically scheduled by DCI format 0_0 or 0_1 and can be semi-statically operated by a configured grant. If a codebook-based PUSCH is dynamically scheduled by DCI format 0_1 or is semi-statically configured by a configured grant, a UE determines a precoder for a PUSCH transmission based on an SRS resource indicator (SRI), a transmission precoding matrix indicator (TPMI), and a transmission rank (a number of PUSCH transmission layers).

[0252] The SRI can be given by SRS resource indicator (a field within DCI) or configured by srs-ResourceIndicator (higher layer signaling). During codebook-based PUSCH transmission, the UE has at least one SRS resource configured for it and can have at most two SRS resources configured for it. If the SRI is provided to the UE by DCI, the SRS resource indicated by the corresponding SRI refers to the SRS resource corresponding to the SRI among the SRS resources transmitted before the PDCCH including the corresponding SRI. In addition, the TPMI and the transmission rank can be given by "precoding information and number of layers" (a field within DCI) or configured by precodingAndNumberOfLayers (higher layer signaling). The TPMI is used to indicate the precoder to be applied to the PUSCH transmission. If one SRS resource is configured for the UE, the TPMI can be used to indicate the precoder to be applied in the configured one SRS resource. If multiple SRS resources are configured for the UE, the TPMI is used to indicate the precoder to be applied in the SRS resource indicated by the SRI.

[0253] The precoder to be used for PUSCH transmission is selected from the uplink codebook with the same number of antenna ports and the value of nrofSRS-Ports within SRS-Config (higher layer signaling). In conjunction with codebook-based PUSCH transmission, the UE determines the codebook subset based on codebookSubset and TPMI within pusch-Config (higher layer signaling). Based on the UE capability reported by the UE to the base station, codebookSubset within pusch-Config (higher layer signaling) can be configured to one of “fullyAndPartialAndNonCoherent”, “partialAndNonCoherent”, and “noncoherent”. If the UE reports “partialAndNonCoherent” as the UE capability, the UE does not expect the value of codebookSubset (higher layer signaling) to be configured as “fullyAndPartialAndNonCoherent”. Furthermore, if the UE reports “noncoherent” as the UE capability, the UE does not expect the value of codebookSubset (higher layer signaling) to be configured as “fullyAndPartialAndNonCoherent” or “partialAndNonCoherent”. If the value of nrofSRS-Ports within SRS-ResourceSet (higher layer signaling) indicates two SRS antenna ports, the UE does not expect the value of codebookSubset (higher layer signaling) to be configured as “partialAndNonCoherent”.

[0254] The UE can have one SRS resource set configured for it (where the value of usage within SRS-ResourceSet (higher layer signaling) is “codebook”) and can indicate one SRS resource by the SRI within the corresponding SRS resource set. If multiple SRS resources are configured within the SRS resource set (where the value of usage within SRS-ResourceSet (higher layer signaling) is “codebook”), the UE expects the value of nrofSRS-Ports within SRS-Resource (higher layer signaling) to be the same for all SRS resources.

[0255] The UE transmits one or more SRS resources included in an SRS resource set (where the value of usage is configured as "codebook" according to upper layer signaling) to the base station, and the base station selects one SRS resource from the SRS resources transmitted by the UE, and instructs the UE to be able to transmit PUSCH by using the transmission beam information of the corresponding SRS resource. In connection with codebook-based PUSCH transmission, SRI is used as information for selecting an index of one SRS resource and is included in DCI. In addition, the base station adds information indicating the rank and TPMI to be used by the UE for PUSCH transmission to the DCI. Using the SRS resource indicated by the SRI, the UE applies the precoder indicated by the rank and TPMI indicated based on the transmission beam of the corresponding SRS resource when performing PUSCH transmission, thereby performing PUSCH transmission.

[0256] Next, non-codebook-based PUSCH transmission will be described. Non-codebook-based PUSCH transmission can be dynamically scheduled through DCI format 0_0 or 0_1, and can be operated semi-statically through a configured grant. If at least one SRS resource is configured within an SRS resource set (where the value of usage within SRS-ResourceSet (upper layer signaling) is "nonCodebook"), non-codebook-based PUSCH transmission can be scheduled for the UE through DCI format 0_1.

[0257] = For an SRS resource set (where the value of usage within SRS-ResourceSet (upper layer signaling) is "nonCodebook"), one connected NZP CSI-RS resource (non-zero power CSI-RS) can be configured for the UE. The UE can calculate the precoder for SRS transmission by measuring the NZP CSI-RS resource connected to the SRS resource set. If the difference between the last received symbol of the aperiodic NZP CSI-RS resource connected to the SRS resource set and the first symbol of the aperiodic SRS transmission is less than 42 symbols in the UE, the UE does not expect information about the precoder for SRS transmission to be updated.

[0258] If the configured value of resourceType within SRS-ResourceSet (higher layer signaling) is "aperiodic", the connected NZP CSI-RS is indicated by SRS request (a field within DCI format 0_1 or 1_1). If the connected NZP CSI-RS resource is aperiodic NZP CSI-RS resource, the presence of connected NZP CSI-RS is indicated for the case that the value of SRS request (a field within DCI format 0_1 or 1_1) is not "00". The corresponding DCI should not indicate cross-carrier or cross-BWP scheduling. In addition, if the value of SRS request indicates the presence of NZP CSI-RS, the NZP CSI-RS is located in the slot in which the PDCCH including the SRS request field is transmitted. In this case, the TCI state configured for the scheduled subcarriers is not configured as QCL-TypeD.

[0259] If there is a configured periodic or semi-persistent SRS resource set, the connected NZP CSI-RS can be indicated by associatedCSI-RS within SRS-ResourceSet (higher layer signaling). For non-codebook-based transmission, the UE does not expect that spatialRelationInfo (higher layer signaling) and associatedCSI-RS within SRS-ResourceSet (higher layer signaling) for a SRS resource will be configured together.

[0260] If multiple SRS resources are configured for a UE, the UE can determine the precoder and transmission rank to be applied for PUSCH transmission based on the SRI indicated by the base station. The SRI can be indicated by SRS resource indicator (a field within DCI) or configured by srs-ResourceIndicator (higher layer signaling). Similar to the above codebook-based PUSCH transmission, if the UE is provided with SRI by DCI, the SRS resource indicated by the corresponding SRI refers to the SRS resource corresponding to the SRI among the SRS resources transmitted before the PDCCH including the corresponding SRI. The UE can use one or multiple SRS resources for SRS transmission, and the maximum number of SRS resources that can be transmitted simultaneously in one SRS resource set and the maximum number of SRS resources are determined by the UE capability reported by the UE to the base station. The SRS resources transmitted simultaneously by the UE occupy the same RB. The UE configures one SRS port for each SRS resource. There can be only one configured SRS resource set (the value of usage within SRS-ResourceSet (higher layer signaling) is "nonCodebook"), and up to four SRS resources can be configured for non-codebook-based PUSCH transmission.

[0261] The base station transmits one NZP-CSI-RS connected to an SRS resource set to the UE, and the UE calculates a precoder to be used when transmitting one or more SRS resources within the corresponding SRS resource set based on a measurement result when the corresponding NZP-CSI-RS is received. The UE applies the calculated precoder when transmitting one or more SRS resources within the SRS resource set (in which the configured usage is "nonCodebook") to the base station, and the base station selects one or more SRS resources from the received one or more SRS resources. In connection with non-codebook-based PUSCH transmission, the SRI indication can express an index of one SRS resource or a combination of multiple SRS resources, and the SRI is included in the DCI. The number of SRS resources indicated by the SRI transmitted by the base station can be the number of transmission layers of the PUSCH, and the UE transmits the PUSCH by applying the precoder applied to the SRS resource transmission to each layer.

[0262] [PUSCH: preparation procedure time]

[0263] Next, the PUSCH preparation procedure time will be described. If the base station schedules the UE to transmit the PUSCH by using the DCI format 0_0, 0_1, or 0_2, the UE can require the PUSCH preparation procedure time so that the PUSCH is transmitted by applying the transmission method (SRS resource transmission precoding method, number of transmission layers, spatial domain transmission filter) indicated through the DCI. In consideration of this, the PUSCH preparation procedure time is defined in NR. The PUSCH preparation procedure time of the UE can follow Equation 2 given below.

[0264] [Equation 2]

[0265] T proc,2 = max(( N2+ d 2,1 + d2)( 2048 + 144 ) κ2 -μ T c + T ext + T switch , d 2,2 )

[0266] Each of the parameters in T proc,2 described in Equation 2 above can have the following meanings.

[0267] - N2: The number of symbols determined according to the UE processing capability 1 or 2 based on the capability of the UE and the base parameter set μ. If the UE processing capability 1 is reported according to the capability report of the UE, N2 can have the values in Table 22, and if the UE processing capability 2 is reported and if the availability of the UE processing capability 2 is configured through upper layer signaling, N2 can have the values in Table 23.

[0268] [Table 22]

[0269]

[0270] [Table 23]

[0271]

[0272] -d 2,1 The number of symbols that are determined to be 0 if all resource elements of the first OFDM symbol transmitted by PUSCH include DM-RS, and otherwise determined to be 1.

[0273] -κ:64

[0274] -μ: follow and Among them, T proc,2 A larger value. This refers to the basic set of downlink parameters used to send the PDCCH of the DCI, including the scheduling PUSCH, and... This refers to the basic set of uplink parameters used to send PUSCH.

[0275] -T c :have .

[0276] -d 2,2 If the DCI of the PUSCH scheduling indicates a BWP switch, then the BWP switch time is followed; otherwise, it is 0.

[0277] -d2: If OFDM symbols overlap in time between a PUSCH with a high-priority index and a PUCCH with a low-priority index, then the d2 value of the PUSCH with the high-priority index is used. Otherwise, d2 is 0.

[0278] -T ext If the UE uses a shared spectrum channel access scheme, then the UE can calculate T. ext And apply it to the PUSCH preparation procedure time. Otherwise, assume T ext It is 0.

[0279] -T switch If the uplink handover interval has been triggered, then T switch This is assumed to be the switching interval time. Otherwise, assume T. switch It is 0.

[0280] Considering the timing advance between uplink and downlink and the impact of time domain resource mapping information of PUSCH scheduled by DCI, if the first symbol of PUSCH is earlier than T proc,2 If the first uplink symbol after the CP starts, then the base station and the UE determine that the PUSCH preparation procedure time is not sufficient. Otherwise, the base station and the UE determine that the PUSCH preparation procedure time is sufficient. The UE can transmit the PUSCH only when the PUSCH preparation procedure time is sufficient, and can ignore the DCI scheduling the PUSCH if the PUSCH preparation procedure time is not sufficient.

[0281] [About CA / DC]

[0282] Figure 10 A radio protocol structure of a base station and a UE in a single cell, carrier aggregation, and dual connectivity scenarios according to embodiments of the disclosure is shown.

[0283] Reference Figure 10 The radio protocol of the next-generation mobile communication system includes, on each of the UE side and the NR base station side, an NR service data adaptation protocol (SDAP) 1025 or 1070, an NR packet data convergence protocol (PDCP) 1030 or 1065, an NR radio link control (RLC) 1035 or 1060, and an NR medium access control (MAC) 1040 or 1055.

[0284] The main functions of the NR SDAP 1025 or 1070 can include some of the following functions.

[0285] - Transfer of user plane data

[0286] - Mapping between QoS (quality of service) flows and DRBs (data radio bearers) for both DL and UL

[0287] - Marking QoS flow ID in both DL and UL packets

[0288] - Reflective QoS flow to DRB mapping for UL SDAP PDUs (protocol data units)

[0289] For the SDAP layer device, whether the UE uses a header of the SDAP layer device or a function of the SDAP layer device for each PDCP layer device or each bearer or each logical channel can be configured through an RRC message, and if the SDAP header is configured, a non-access stratum (NAS) QoS reflection configuration 1-bit indicator (NAS reflective QoS) and an AS (access stratum) QoS reflection configuration 1-bit indicator (AS reflective QoS) of the SDAP header can be indicated, so that the UE can update or reconfigure mapping information about a QoS flow and a data bearer for uplink and downlink. The SDAP header can include QoS flow ID information indicating QoS. The QoS information can be used as data processing priority, scheduling information, etc. in order to smoothly support services.

[0290] The main functions of the NR PDCP 1030 or 1065 can include some of the following functions:

[0291] - header compression and decompression: only ROHC (Robust Head Compression protocol)

[0292] - transfer of user data

[0293] - in-sequence delivery of upper layer PDUs

[0294] - out-of-sequence delivery of upper layer PDUs

[0295] - reordering of received PDCP PDUs

[0296] - duplicate detection of lower layer SDUs (service data unit)

[0297] - retransmission of PDCP SDUs

[0298] - ciphering and deciphering

[0299] - timer-based SDU discard in uplink

[0300] The above reordering of the NR PDCP device refers to a function of reordering PDCP PDUs received from a lower layer in order based on a PDCP sequence number (SN), and can include a function of transferring data to an upper layer in the order of reordering. Alternatively, the reordering of the NR PDCP device can include a function of immediately transferring data without considering the order, can include a function of recording PDCP PDUs missing due to reordering, can include a function of reporting a status of the missing PDCP PDUs to a transmission side, and can include a function of requesting retransmission of the missing PDCP PDUs.

[0301] The main functions of the NR RLC 1035 or 1060 can include some of the following functions:

[0302] - Transfer of upper layer PDUs

[0303] - In-sequence delivery of upper layer PDUs

[0304] - Out-of-sequence delivery of upper layer PDUs

[0305] - Error correction through ARQ

[0306] - Concatenation, segmentation, and reassembly of RLC SDUs

[0307] - Re-segmentation of RLC data PDUs

[0308] - Reordering of RLC data PDUs

[0309] - Duplicate detection

[0310] - Protocol error detection

[0311] - RLC SDU discard

[0312] - RLC re-establishment

[0313] The above-mentioned in-sequence delivery of the NR RLC device refers to a function of delivering RLC SDUs received from a lower layer to an upper layer in sequence. The in-sequence delivery of the NR RLC device can include a function of reassembling and delivering a plurality of RLC SDUs received if one original RLC SDU has been segmented, can include a function of reordering received RLC PDUs with reference to an RLC sequence number (SN) or a PDCP sequence number (SN), can include a function of recording missing RLC PDUs due to reordering, can include a function of reporting a status of missing RLC PDUs to a transmitting side, and can include a function of requesting retransmission of missing RLC PDUs. The in-sequence delivery of the NR RLC device can include a function of delivering only RLC SDUs before a missing RLC SDU to an upper layer in sequence if there is the missing RLC SDU, and can include a function of delivering all RLC SDUs received before a timer is started to the upper layer in sequence if the predetermined timer has expired although there is the missing RLC SDU. Alternatively, the in-sequence delivery of the NR RLC device can include a function of delivering all RLC SDUs received until now to the upper layer in sequence if the predetermined timer has expired although there is the missing RLC SDU. Further, the in-sequence delivery of the NR RLC device can include a function of processing RLC PDUs in the received order (in the order of arrival regardless of the sequence number order) and delivering them to a PDCP device regardless of the order (out-of-sequence delivery), and can include a function of receiving segments stored in a buffer or to be received later in the case of segmentation, reconfiguring them into one complete RLC PDU, processing them, and delivering them to the PDCP device. The NR RLC layer can not include a splicing function, which can be performed in the NR MAC layer or replaced with a multiplexing function of the NR MAC layer.

[0314] The out-of-sequence delivery of the NR RLC device refers to a function of immediately delivering RLC SDUs received from a lower layer to an upper layer regardless of the order, can include a function of reassembling and delivering a plurality of RLC SDUs if one original RLC SDU has been segmented, and can include a function of storing RLC SNs or PDCP SNs of received RLC PDUs and recording missing RLC PDUs due to reordering.

[0315] The NR MAC 1040 or 1055 can be connected to a plurality of NR RLC layer devices configured in one UE, and the main functions of the NR MAC can include some of the following functions.

[0316] - Mapping between logical channels and transport channels

[0317] - Multiplexing / demultiplexing of MAC SDUs

[0318] - Scheduling information reporting

[0319] - Error correction through HARQ

[0320] - Priority handling between logical channels of one UE

[0321] - Priority handling between UEs through means of dynamic scheduling

[0322] - MBMS (multimedia broadcast multicast service) service identification

[0323] - Transport format selection

[0324] - Padding

[0325] The NR PHY layer 1045 or 1050 can perform the following operations: channel coding and modulation on upper layer data, thereby obtaining OFDM symbols, and delivering them through a radio channel, or demodulating OFDM symbols received through a radio channel, channel-decoding them, and delivering them to an upper layer.

[0326] The detailed structure of the radio protocol structure can be changed differently according to a carrier (or cell) operation scheme. For example, in the case of a base station transmitting data to a UE based on a single carrier (or cell), the base station and the UE can use a protocol structure having a single structure for each layer, such as 400. In contrast, in the case of a base station transmitting data to a UE based on carrier aggregation (CA) using multiple carriers in a single TRP, the base station and the UE can use a protocol structure having a single structure up to the RLC but multiplexing the PHY layer through the MAC layer, such as 410. As another example, in the case of a base station transmitting data to a UE based on dual connectivity (DC) using multiple carriers in multiple TRPs, the base station and the UE can use a protocol structure having a single structure up to the RLC but multiplexing the PHY layer through the MAC layer, such as S20.

[0327] Referring to the above description related to PDCCH and beam configuration, PDCCH repetition transmission is not supported in the current Rel-15 and Rel-16 NR, and thus it can be difficult to achieve the required reliability in a scenario requiring high reliability, such as URLLC. The present disclosure can improve PDCCH reception reliability of a UE by providing a PDCCH repetition transmission method through multiple transmission points (TRPs). Its specific method will be described through the following embodiments below.

[0328] Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings. The contents of the disclosure can be applied to FDD and TDD systems. As used herein, upper signaling (or upper layer signaling) is a method for transmitting a signal from a base station to a UE by using a downlink data channel of a physical layer, or transmitting a signal from a UE to a base station by using an uplink data channel of a physical layer, and the upper signaling can also be referred to as "RRC signaling", "PDCP signaling", or "medium access control (MAC) control element (MAC CE)".

[0329] Hereinafter, in the disclosure, the UE can determine whether to apply coordinated communication using various methods, for example, a PDCCH allocating a PDSCH to which coordinated communication is applied has a specific format, or a PDCCH allocating a PDSCH to which coordinated communication is applied includes a specific indicator indicating whether to apply coordinated communication, or a PDCCH allocating a PDSCH to which coordinated communication is applied is scrambled by a specific RNTI, or assumes that coordinated communication is applied within a specific range indicated by an upper layer. Hereinafter, for convenience of description, it will be assumed that a non-coherent joint transmission (NC-JT) case refers to a case in which a UE receives a PDSCH to which coordinated communication is applied based on conditions similar to the above conditions.

[0330] Hereinafter, determining a priority between A and B can be variously described as, for example, selecting an entity having a higher priority according to a predetermined priority rule and performing an operation corresponding thereto, or omitting or discarding an operation with respect to an entity having a lower priority.

[0331] Hereinafter, the above-described examples can be described through several embodiments, but they are not independent of each other, and one or more embodiments can be applied simultaneously or in combination.

[0332] Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings. In the following description, a base station is an entity that allocates resources to a terminal, and can be at least one of a gNode B, a gNB, an eNode B, a Node B, a base station (BS), a radio access unit, a base station controller, and a node on a network. The terminal can include a user equipment (UE), a mobile station (MS), a cellular phone, a smartphone, a computer, or a multimedia system capable of performing a communication function. In the following description of embodiments of the disclosure, a 5G system will be described by way of example, but embodiments of the disclosure can also be applied to other communication systems having a similar technical background or channel type. Examples of such a communication system can include an LTE or LTE-A mobile communication system and a mobile communication technology developed beyond 5G. Therefore, embodiments of the disclosure can also be applied to other communication systems with some modifications based on the determination of those skilled in the art, without significantly departing from the scope of the disclosure. The content of the disclosure can be applied to FDD and TDD systems.

[0333] Further, in describing the disclosure, detailed descriptions of known functions or configurations incorporated herein will be omitted when it is determined that the description can unnecessarily obscure the subject matter of the disclosure. The terms to be described below are terms defined in consideration of the functions in the disclosure, and can differ according to users, user's intentions, or habits. Therefore, the definition of the terms should be made based on the content of the entire specification.

[0334] In the following description of the disclosure, upper layer signaling can refer to signaling corresponding to at least one of the following signaling, or a combination of one or more thereof.

[0335] - Master Information Block (MIB)

[0336] - System Information Block (SIB) or SIB X (X = 1, 2,...)

[0337] - Radio Resource Control (RRC)

[0338] - Medium Access Control (MAC) Control Element (CE)

[0339] In addition, L1 signaling can refer to signaling corresponding to at least one of the signaling methods using the following physical layer channels or signaling, or a combination of one or more thereof.

[0340] - Physical Downlink Control Channel (PDCCH)

[0341] - Downlink Control Information (DCI)

[0342] - UE-specific DCI

[0343] - Group-common DCI

[0344] - common DCI

[0345] - scheduling DCI (e.g., DCI used for the purpose of scheduling downlink or uplink data)

[0346] - non-scheduling DCI (e.g., DCI not used for the purpose of scheduling downlink or uplink data)

[0347] - physical uplink control channel (PUCCH)

[0348] - uplink control information (UCI)

[0349] Hereinafter, determining the priority between A and B can be variously described, for example, selecting an entity having a higher priority according to a predetermined priority rule and performing an operation corresponding thereto, or omitting or discarding an operation with respect to an entity having a lower priority.

[0350] Hereinafter, the above-described examples can be described through several embodiments, but they are not independent of each other, and one or more embodiments can be applied simultaneously or in combination.

[0351] [Type 1 HARQ-ACK codebook related]

[0352] A method for configuring a Type 1 HARQ-ACK codebook in an NR system is described. The Type 1 HARQ-ACK codebook can also be referred to as a semi-static HARQ-ACK codebook.

[0353] In the following description, only one PUCCH can be available for a UE to transmit HARQ-ACK information in one time unit (e.g., a slot, a sub-slot, or a mini-slot). Unless otherwise specified, the time unit is described as a slot, but can be extended to a sub-slot, a mini-slot, etc.

[0354] A UE can receive a semi-static HARQ-ACK codebook configuration from a base station. The configuration can be configured via an upper layer signal (e.g., an RRC signal). The UE can receive a DCI format from the base station. The UE can transmit HARQ-ACK information for a PDSCH or SPS PDSCH release or Scell dormancy indication scheduled by the DCI format in a slot indicated by a value of a PDSCH-to-HARQ_feedback timing indicator field in the DCI format. When the UE is instructed to transmit multiple pieces of HARQ-ACK information in one slot, the UE can generate the multiple pieces of HARQ-ACK information into a HARQ-ACK codebook according to a predetermined rule, and can transmit the same via one PUCCH in the slot.

[0355] The specific rule for generating the semi-static HARQ-ACK codebook is as follows.

[0356] The UE reports the HARQ-ACK information bit value of NACK in the HARQ-ACK codebook in the slot not indicated by the PDSCH-to-HARQ_feedback timing indicator field of the DCI format.

[0357] When the UE only reports the HARQ-ACK information about one SPS PDSCH release or one PDSCH reception in all M A,C cases of candidate PDSCH receptions, and the report is scheduled by the DCI format 1_0 in the Pcell, which includes the information of the counter DACI field indicating 1, the UE determines one HARQ-ACK codebook for the SPS PDSCH release or the PDSCH reception.

[0358] The other cases follow the HARQ-ACK codebook determination method according to the following method.

[0359] In this disclosure, for convenience, the PDSCH-to-HARQ_feedback timing indicator value is referred to as the K1 value. The UE can have multiple K1 values configured, and the multiple K1 values are collectively referred to as the K1 set.

[0360] The set of PDSCH reception candidate occasions in the serving cell c is referred to as M A,c , and the method for obtaining or calculating M A,c is described below.

[0361] First, it is assumed that the PDSCH scheduled by the DCI format is received in a single slot, which can include the case that the pdsch-AggregationFactor is not configured by the upper layer.

[0362] When the PUCCH or PUSCH for delivering the type 1 HARQ-ACK codebook is sent in the slot n, its pseudo code is as follows.

[0363] [Pseudo code 1: (PDSCH reception without repetition)]

[0364] - Preparation operation: The set R is a set of multiple pieces of scheduling information (e.g., slot information to which a PDSCH is mapped (hereinafter, K0 value) and starting symbol and length information (e.g., starting and length value (SLIV) hereinafter)) configured in a time domain resource assignment (TDRA) table. When the UE monitors one or more DCI formats and the DCI formats use different TDRA tables, the set R is generated based on all the TDRA tables.

[0365] - Operation 0: M A,c is initialized to an empty set. k is initialized to 0. j is initialized to 0.

[0366] - Operation 1: The k-th largest K1 value is selected from the configured set of K1 values. (For example, when k = 0, the largest K1 value is selected from the set of K1 values, and when k = 1, the second largest K1 value is selected from the set of K1 values.) The K1 value is referred to as K 1,k .

[0367] - Operation 2: When the symbols corresponding to the starting symbol and length information (SLIV) of each row belonging to the set R overlap with the symbols configured for uplink in the upper layer in the slot (slot n - K 1,k value) corresponding to the K 1,k , the row can be excluded from the set R.

[0368] - Operation 3-1 (when the UE has a UE capability of receiving at most one unicast PDSCH in a single slot): When the determined set R is not an empty set, j is added to the set M A,c as a new PDSCH reception candidate occasion. When one of the PDSCH candidates in the set R is received, the UE can position the HARQ-ACK of the one PDSCH in the new PDSCH reception candidate occasion j. j is increased by 1.

[0369] - Operation 3-2 (when the UE has a UE capability of receiving more than one unicast PDSCH in a single slot): For the SLIV that ends first in the determined set R and the SLIV overlapping in time with the SLIV, j is added to the set M A,c as a new PDSCH reception candidate occasion. When one of the PDSCH candidates with the SLIV is received, the UE can position the HARQ-ACK of the one PDSCH in the new PDSCH reception candidate occasion j. j is increased by 1. The SLIV is excluded from the set R. Operation 3-2 is repeated until the set R is an empty set.

[0370] - Operation 4: k is increased by 1. When k is smaller than the cardinality of the K1 set, pseudo code 1 is restarted from operation 2, and when k is equal to or greater than the cardinality of the K1 set, pseudo code 1 is terminated.

[0371] Figure 11a Figure 11b Figure 11c FIG. 1 illustrates a type 1 HARQ-ACK codebook for transmitting HARQ-ACK of a PDSCH according to an embodiment of the disclosure.

[0372] Referring to Figure 11a Figure 11b Figure 11c The UE can perform a PUCCH transmission including HARQ-ACK information in slot n. The HARQ-ACK information can be generated in the form of a type 1 HARQ-ACK codebook.

[0373] The UE can receive uplink / downlink configuration information from the base station. According to the uplink / downlink configuration information, the UE can determine whether a symbol is an uplink symbol, a downlink symbol, or a flexible symbol. For convenience, only uplink symbols are described here, and symbols other than uplink symbols can be downlink symbols or flexible symbols. Referring to Figure 11a All symbols of slot n and slot n-1 can be configured as uplink symbols. The last two symbols of slot n-2 can be configured as uplink symbols.

[0374] It is assumed that K1=2 and K1=3 are configured as K1 values for the UE. That is, the K1 set is {2, 3}. A TDRA table of a DCI format monitored by the UE can include five rows as in Table 24 below. For reference, a K0 value, a SLIV, and a PDSCH mapping type value can be configured in each row, but the PDSCH mapping type is omitted for convenience of description.

[0375] [Table 24]

[0376]

[0377] The UE can include each SLIV row of the TDRA table in Table 24 in the set R according to a preparation operation. Table 24 illustrates SLIVs according to each row. The UE can determine PDSCH reception candidate opportunities M A,c Referring to Figure 11a Figure 11b Figure 11c Pseudo code 1 can be explained as follows. In the following description, it is assumed that the UE has a UE capability of receiving more than one unicast PDSCH in a single slot.

[0378] - Operation 0: M A,c ​​​​​​is initialized to an empty set. k is initialized to 0. j is initialized to 0.

[0379] - Operation 1: Select the (k = 0)th largest K1 value from the configured set of K1 values. The K1 value is K 1,0 = 3.

[0380] - Operation 2: When the symbols corresponding to the start symbol and length information (SLIV) of each SLIV row belonging to the set R overlap with the symbols configured for uplink in the upper layer in slot n - k 1，0 = 3, the SLIV row including the SLIVs overlapping with these symbols can be excluded from the set R. Referring to Figure 11b , when some symbols in slot n - 3 are semi-static uplink (UL) symbols configured by the upper layer, the SLIV row including the SLIVs overlapping with these symbols can be excluded from the set R. Referring to Figure 11b , since no semi-static uplink symbols are configured in slot n - 3, all SLIV rows can not be excluded from the set R. The set R can include {1, 2, 3, 4, 5}.

[0381] - Operation 3-2 (when the UE has a UE capability of receiving more than one unicast PDSCH in a single slot)

[0382] For the SLIV that ends first in the determined set R and the SLIVs overlapping in time with this SLIV, j = 0 is added to the set M A,c as a new PDSCH reception occasion. Here, the SLIV that ends first is SLIV1 (0, 4) in row 1, and the SLIVs overlapping with this SLIV are SLIV2 (0, 7) in row 2 and SLIV5 (0, 14) in row 5. Therefore, j = 0 is added to M A,c , and when the UE receives a PDSCH scheduled by SLIV1 (0, 4) in row 1, SLIV2 (0, 7) in row 2, or SLIV5 (0, 14) in row 5 in slot n - 3, the UE can include the HARQ-ACK of this PDSCH in the first (j = 0) M A,c corresponding positioning. j is increased to j = 1. The SLIV rows of rows 1, 2, and 5 are excluded from the set R, and thus R = {3, 4}. Since the set R is not an empty set, operation 3-2 is repeated.

[0383] For the SLIV that ends first in the determined set R and the SLIVs overlapping in time with this SLIV, j = 1 is added to the set M A,cas a new PDSCH reception candidate occasion. Here, the first ending SLIV is SLIV 4 (7, 4) in row 4, and the SLIV overlapping with this SLIV is SLIV 3 (7, 7) in row 3. Thus, when j = 1 is added to M A,c , and when the UE receives a PDSCH scheduled by SLIV 4 (7, 4) in row 4 or SLIV 3 (7, 7) in row 3 in slot n-3, the UE can include the HARQ-ACK of this PDSCH in the Type 1 HARQ-ACK codebook in the second (j = 1) M A,c corresponding positioning. j is increased to j = 2. SLIVs of row 3 and row 4 are excluded from the set R, and thus R becomes an empty set. Thus, operation 3-2 can be terminated.

[0384] - Operation 4: k is increased to k = 1. Since k = 1 and the cardinality of the K1 set is 2, the process is restarted from operation 2 by using the next K1 value. Now, K 1,1 = 2.

[0385] - Operation 2: When the symbols corresponding to the starting symbol and length information (SLIV) of each SLIV row belonging to the set R overlap with the symbols configured for uplink in the upper layer in slot n-k 1，1 = n-2, the row can be excluded from the set R. Referring to Figure 11b , when some symbols in slot n-2 are semi-static uplink (UL) symbols configured by the upper layer, the row including the SLIV overlapping with these symbols can be excluded from the set R. Referring to Figure 11b , semi-static uplink symbols are configured in slot n-2, and row 3 and row 5 overlap with the semi-static uplink symbols. Thus, SLIV row 3 and SLIV row 5 can be excluded from the set R. The set R can include {1, 2, 4}.

[0386] - Operation 3-2 (when the UE has a UE capability of receiving more than one unicast PDSCH in a single slot)

[0387] For the first ending SLIV in the determined set R and the SLIV overlapping in time with this SLIV, j = 2 is added to the set M A,c as a new PDSCH reception candidate occasion. Here, the first ending SLIV is SLIV 1 (0, 4) in row 1, and the SLIV overlapping with this SLIV is SLIV 2 (0, 7) in row 2. Thus, j = 2 is added to M A,cand when the UE receives a PDSCH scheduled by SLIV1 (0, 4) in row 1 or SLIV2 (0, 7) in row 2 in slot n-3, the UE can include the HARQ-ACK of the PDSCH in the third (j = 2) M A,c corresponding positioning. j is increased to j = 3. SLIVs of row 1 and row 2 are excluded from set R, and thus R = {4}. Since set R is not an empty set, operation 3-2 is repeated.

[0388] For the SLIV that ends first in the determined set R and the SLIVs that overlap in time with the SLIV, j = 3 is added to set M A,c as a new PDSCH reception occasion. Here, the SLIV that ends first is SLIV4 (7, 4) in row 4, and there is no SLIV that overlaps with the SLIV. Thus, when j = 3 is added to M A,c , and when the UE receives a PDSCH scheduled by SLIV4 (7, 4) in row 4 in slot n-3, the UE can include the HARQ-ACK of the PDSCH in the fourth (j = 3) M A,c corresponding positioning. j is increased to j = 4. SLIV of row 4 is excluded from set R, and thus R becomes an empty set. Thus, operation 3-2 can be terminated.

[0389] - Operation 4: k is increased to k = 2. Since k = 1 and the cardinality of the K1 set is 2, the pseudo code is terminated.

[0390] Reference Figure 11c , the UE can determine M A,c corresponding to four PDSCH reception occasions j = 0, j = 1, j = 2, and j = 3. Here, M A,C corresponding to j = 0 and M A,C corresponding to j = 1 are PDSCH reception occasions in slot n-3, and M A,C corresponding to j = 2 and M A,C corresponding to j = 3 are PDSCH reception occasions in slot n-2. The size of the Type 1 HARQ-ACK codebook can be determined according to the number of PDSCH reception occasions. The number of actual bits for each PDSCH reception occasion can be determined according to the configuration, such as the number of transport blocks (TBs) included in each PDSCH, the number of code block groups (CBGs) included in each PDSCH, and spatial bundling.

[0391] [First Embodiment: PDSCH processing according to UE capability]

[0392] According to an embodiment of the disclosure, the UE can design a HARQ-ACK codebook according to the UE capability.

[0393] The UE capability can refer to a set of functions available according to an implementation of the UE by a UE manufacturer. The UE can report the UE capability to the base station upon connection to the cell, which can be referred to as a UE capability report. The base station can obtain the UE capability of the UE (RRC-connected UE) connected to its cell through the UE capability report from the UE.

[0394] According to the disclosure, the UE can transmit one of the following UE capabilities to the base station through the UE capability report.

[0395] The UE can report the maximum number of PDSCHs that the UE can process in a single slot as the UE capability. Here, "processing" can refer to a series of processes of receiving the PDSCH and generating a HARQ-ACK indicating whether the PDSCH has been successfully received.

[0396] For example, the UE can report the UE capability of processing up to N PDSCHs in one slot to the base station through the UE capability report, and when the base station schedules more than N PDSCHs for the UE in one slot, the UE cannot receive more than N PDSCHs in one slot. That is, preferably, the base station schedules at most N PDSCHs for the UE in one slot, and preferably, the base station does not schedule more than N PDSCHs in one slot.

[0397] Here, the scheduled PDSCHs can not overlap in the time domain. That is, when N PDSCHs are scheduled in one slot, the N PDSCHs can not overlap each other in the time domain and can be positioned in different symbols.

[0398] N can have at least one value of 1, 2, 4, and 7.

[0399] In the disclosure, the UE capability includes the maximum number of PDSCHs that the UE can process in one slot. However, the UE capability can include the maximum number of PDSCHs that the UE can process in a specific time period (a mini-slot, a plurality of slots, etc.) rather than in one slot. In this case, the slot in the embodiment of the disclosure can be interpreted as being replaced by the specific time period.

[0400] According to an embodiment of the disclosure, when the base station schedules more than N PDSCHs (for example, M (M>N) PDSCHs) for the UE in one slot, the UE can perform at least one of the following operations.

[0401] According to the first method, the UE can select N PDSCHs from the M PDSCHs and can receive the N PDSCHs.

[0402] The UE can select the N PDSCHs from the M PDSCHs according to a time order. More specifically, the UE can select the N PDSCHs that are scheduled in a first symbol from the M PDSCHs in a time order. The UE can determine an index of a symbol in a slot where the PDSCH is scheduled. The UE can determine an index of a first symbol to a last symbol where the PDSCH is scheduled. The UE can select the N PDSCHs that have a lowest index (a first symbol in time) among indices of the M PDSCHs, and can process the N PDSCHs.

[0403] The N PDSCHs can be selected according to a time order of DCIs corresponding to the M PDSCHs. More specifically, the N PDSCHs corresponding to N DCIs that are positioned later in time among the DCIs corresponding to the M PDSCHs can be selected. The UE can determine an index of a slot where a DCI scheduling a PDSCH (a DCI corresponding to the PDSCH) is positioned or an index of a symbol in a slot. The DCI can be received through a PDCCH, and the UE can determine an index of a slot where the PDCCH is received and an index of a symbol in the slot where the PDCCH is received (a first symbol of the PDCCH or a last symbol of the PDCCH when the PDCCH corresponds to a plurality of symbols). The UE can determine N DCIs that are positioned latest in time among the DCIs corresponding to the M PDSCHs, because information included in a PDSCH scheduled later by a base station via a DCI can be more important in a case where the UE is scheduled later.

[0404] When the UE selects the N PDSCHs to be processed, the UE can prefer to include a PDSCH that is scheduled by a downlink control information (DCI) among the M PDSCHs. The PDSCH can be scheduled by two methods. In a first method, the PDSCH can be scheduled by a DCI. The UE can receive a PDCCH, and the PDCCH can include the DCI. The DCI can include scheduling information about the PDSCH. For reference, the DCI including the scheduling information about the PDSCH can be one of a DCI format 1_0, a DCI format 1_1, a DCI format 1_2, and a DCI format 1_3. In a second method, the PDSCH can be periodically scheduled by an upper layer signal. The PDSCH scheduled by this method can be referred to as an SPS PDSCH. Unlike the PDSCH scheduled by the DCI, the SPS PDSCH can not have a corresponding DCI. Accordingly, the base station is not able to dynamically control scheduling information about the SPS PDSCH for the UE. Accordingly, the PDSCH scheduled by the DCI that is dynamically controllable by the DCI can be preferred.

[0405] When the UE selects N PDSCHs to be processed, the UE can prefer to include PDSCHs having high priority among the M PDSCHs. The UE can determine the priority of each PDSCH. The priority can be dynamically indicated in DCI scheduling the PDSCH or configured in an upper layer signal. The priority can include "0" and "1", where "0" can correspond to a PDSCH having low priority and "1" can correspond to a PDSCH having high priority. The UE can prefer to select PDSCHs having high priority (i.e., PDSCHs corresponding to priority "1") among the M PDSCHs, because PDSCHs having higher priority can transmit more important information.

[0406] When the UE selects N PDSCHs to be processed, the UE can prefer to include PDSCHs having high priority among the M PDSCHs. The UE can determine the priority of each PDSCH. The priority can be dynamically indicated in DCI scheduling the PDSCH or configured in an upper layer signal. The priority can include "0" and "1", where "0" can correspond to a PDSCH having low priority and "1" can correspond to a PDSCH having high priority. The UE can prefer to select PDSCHs having high priority (i.e., PDSCHs corresponding to priority "1") among the M PDSCHs, because PDSCHs having higher priority can transmit more important information.

[0407] When the UE selects N PDSCHs to be processed, the UE can select N PDSCHs based on RNTI scrambling DCI corresponding to the M PDSCHs. That is, the UE can prefer to include PDSCHs corresponding to DCI scrambled with a specific RNTI. For example, DCI corresponding to a PDSCH can be scrambled with C-RNTI, CS-RNTI, or MCS-C-RNTI. MCS-C-RNTI is an RNTI for transmitting a PDSCH with higher reliability, and CS-RNTI can be used to activate or retransmit an SPS PDSCH. The UE can prefer to use DCI scrambled with MCS-C-RNTI. That is, the UE can prefer to select a PDSCH corresponding to DCI scrambled with MCS-C-RNTI. In addition, the UE can prefer to use DCI scrambled with C-RNTI. That is, the UE can prefer to select a PDSCH corresponding to DCI scrambled with C-RNTI. A system information block can be transmitted through a PDSCH scheduled by DCI scrambled with SI-RNTI. When there is DCI scrambled with SI-RNTI, the UE can include a PDSCH scheduled by the DCI as the highest priority among the N PDSCHs. That is, the UE can have to receive the PDSCH including the system information block.

[0408] When the UE selects N PDSCHs to be processed, the UE can preferentially select PDSCHs among the M PDSCHs having a low index corresponding to the PDSCHs. In the case of SPS PDSCHs, a unique index can be assigned to the SPS PDSCHs. For example, an upper layer signal for configuring the SPS PDSCHs can include a unique index of the SPS PDSCHs. Different SPS PDSCHs in one slot can correspond to different unique indexes. That is, the UE can preferentially select SPS PDSCHs having a low index because the base station can transmit more important information in the SPS PDSCH having a low index among a plurality of pieces of information transmitted through the SPS PDSCHs, and thus can prioritize reception of the SPS PDSCH.

[0409] When the UE selects N PDSCHs to be processed, the UE can preferentially select PDSCHs transmitted for a broadcast or multicast purpose among the M PDSCHs. The UE can determine that the PDSCH is transmitted for one of a unicast, a broadcast, and a multicast purpose, which can be based on an RNTI scrambling a DCI format scheduling the PDSCH or an upper layer configuration of the PDSCH. The UE can receive a PDSCH transmitted for a unicast purpose through retransmission, but retransmission of a PDSCH transmitted for a broadcast or multicast purpose can be difficult. Accordingly, the UE can preferentially receive a PDSCH transmitted for a broadcast or multicast purpose, thereby avoiding retransmission of a PDSCH transmitted for an unnecessary broadcast or multicast purpose.

[0410] The UE can select N PDSCHs according to an embodiment-based implementation. Here, "select according to an implementation" means that a method for selecting N PDSCHs is implemented according to the convenience of the UE manufacturer, rather than defining the selection method. The implementation method can be determined by one or a combination of the above-described methods.

[0411] In the method, valid HARQ-ACK information about N PDSCHs selected by the UE can be transmitted to the base station. In addition, valid HARQ-ACK information about M-N PDSCHs not selected can not be transmitted to the base station. That is, the UE can transmit NACK for the M-N PDSCHs to the base station, or can not transmit HARQ-ACK information about the M-N PDSCHs. Even if the UE transmits ACK for the M-N PDSCHs to the base station, the base station can determine that the HARQ-ACK information about the PDSCHs is invalid. The base station determining that the HARQ-ACK information is invalid can be the same as determining NACK.

[0412] According to a second method, when more than N PDSCHs are scheduled for the UE in a slot, the UE can not process PDSCHs other than specific PDSCHs in the slot. Here, the number of specific PDSCHs is not necessarily N, and can be equal to or less than N. That is, the UE can receive only PDSCHs that the UE essentially needs to receive. The specific PDSCHs can be as follows.

[0413] The UE can receive PDSCHs with high priority among PDSCHs scheduled in a slot. The UE can not receive PDSCHs with low priority among PDSCHs scheduled in a slot, which can be performed when the number of PDSCHs with high priority is less than or equal to the maximum number of PDSCHs that the UE can process in a slot. This operation receives only PDSCHs with high priority based on priority only, and the UE can exclude some or all of PDSCHs with low priority.

[0414] The UE can receive PDSCHs scheduled by DCI scrambled with SI-RNTI (PDSCHs including system information blocks) among PDSCHs scheduled in a slot. The UE can not receive PDSCHs scheduled by DCI scrambled with other RNTIs. That is, the UE can receive only PDSCHs for transmitting the most important information.

[0415] The UE can receive only PDSCHs scheduled by DCI among PDSCHs scheduled in a slot. The UE can not receive SPS PDSCHs among PDSCHs scheduled in a slot, which can be performed when the number of PDSCHs scheduled by DCI is less than or equal to the maximum number of PDSCHs that the UE can process in a slot. This operation can be applied assuming that information transmitted through SPS PDSCHs has a lower priority than information included in PDSCHs scheduled by DCI.

[0416] The UE can receive only SPS PDSCHs among PDSCHs scheduled in a slot. The UE can not receive PDSCHs scheduled by DCI among PDSCHs scheduled in a slot, which can be performed when the number of SPS PDSCHs is less than or equal to the maximum number of PDSCHs that the UE can process in a slot. This operation can be applied assuming that information transmitted through PDSCHs scheduled by DCI has a lower priority than information included in SPS PDSCHs.

[0417] According to the third method, when more than N PDSCHs are scheduled for the UE in one slot, the UE can not process all the PDSCHs in the slot. That is, when more than N PDSCHs are scheduled in one slot, the UE can not receive all the PDSCHs scheduled in the slot. In addition, the UE can transmit NACK as HARQ-ACK information on the PDSCHs to the base station.

[0418] When the base station requires the UE to process more PDSCHs than the UE capability in one slot, the method can allow the UE to ignore the scheduling of the base station exceeding the UE capability, and can be advantageous in UE implementation. In the first and second methods, the UE needs a process to select N PUSCHs to be processed in one slot, whereas in the third method, the UE does not process all the scheduled PDSCHs, thereby reducing the complexity of UE implementation.

[0419] In the above-described methods, the UE selects PDSCHs according to the UE capability. Here, it is assumed that the UE has a UE capability to process up to N PDSCHs in one slot. Even though the UE can process up to N PDSCHs, the base station can configure the UE to process a smaller number of PDSCHs than N in one slot. The base station can configure this operation to reduce the power consumption of the UE. The base station can configure this operation according to the implementation of the base station scheduler. That is, the base station can configure the UE to process up to K (< N) PDSCHs in one slot. Here, K can be a value configured for the UE through an upper layer signal. For example, when the UE transmits a UE capability to the base station to process up to N = 7 PDSCHs in one slot, the base station can configure K = 4 for the UE. In this case, the operation of the UE can be changed to receive up to K PDSCHs in one slot. The UE can apply the aforementioned methods by replacing N with K.

[0420] [Second embodiment: Design of HARQ-ACK codebook according to UE capability]

[0421] The present disclosure shows a method of designing a HARQ-ACK codebook based on UE capability.

[0422] For convenience of description, it is assumed that the UE can process up to N PDSCHs in one slot according to the UE capability. For reference, the UE can process up to N PDSCHs in one slot, but the base station can configure the maximum number of PDSCHs to be processed in one slot for the UE. In the following description of the present disclosure, when the UE receives the aforementioned configuration, N is the maximum number of PDSCHs to be processed in one slot configured for the UE by the base station. When the UE does not receive the aforementioned configuration, N is the maximum number of PDSCHs to be processed in one slot determined according to the UE capability.

[0423] To design a HARQ-ACK codebook based on UE capability, the UE can receive the following information configured by the base station. The following information can be configured through an upper layer signal (RRC signal) of the base station.

[0424] As the first information, the UE can receive a K1 value configured by the base station. The K1 value is a value indicating an offset between a PDSCH reception slot and a slot for transmitting HARQ-ACK. The UE can receive one K1 value or multiple K1 values configured by the base station. The K1 values can be collectively referred to as a K1 set.

[0425] As the second information, the UE can receive a configuration of the maximum number of PDSCHs to be processed in one slot. As described above, when there is no configuration, the UE can use the maximum number of PDSCHs to be processed in a slot determined according to the UE capability.

[0426] The UE can have multiple UE capabilities. For example, the maximum number of PDSCHs that the UE can process in one slot can vary according to PRB allocation. For example, the UE can process up to N1 PDSCHs with 136 or less PRBs, and can process up to N2 PDSCHs with more than 136 PRBs. When there are multiple such UE capabilities, the UE can determine the maximum number of PDSCHs to be processed in one slot based on a larger UE capability (i.e., a larger value of N1 and N2) or a smaller UE capability (i.e., a smaller value of N1 and N2).

[0427] Figure 12a and Figure 12b A generation of a HARQ-ACK codebook according to UE capability according to an embodiment of the disclosure is shown.

[0428] Referring to Figure 12a , the UE can transmit a PUCCH in slot n. The PUCCH can include a HARQ-ACK codebook. The HARQ-ACK codebook can include one HARQ-ACK bit or multiple HARQ-ACK bits, and each HARQ-ACK bit can have a corresponding slot and a corresponding PDSCH occasion. That is, when the UE receives a PDSCH, the UE can determine the HARQ-ACK bit position of the PDSCH in the HARQ-ACK codebook based on the slot of the PDSCH and the PDSCH occasion.

[0429] For convenience, it is assumed in the present disclosure that the HARQ-ACK bit corresponding to one PDSCH is 1 bit. However, when the PDSCH includes up to two transport blocks (TBs), the HARQ-ACK bit corresponding to the PDSCH can be 2 bits, and when the PDSCH includes up to X code block groups (CBGs), the HARQ-ACK bit corresponding to the PDSCH can be X bits.

[0430] When the UE transmits the PUCCH in slot n, the HARQ-ACK codebook of the PUCCH can include the HARQ-ACK bit(s) corresponding to the PDSCH received in slot n-k1. Here, K1 can be one of the K1 values configured as the first information. For example, it is assumed that there are four K1 values (k1_0, k1_1, k1_2, and k1_3) configured as the first information. In this case, the HARQ-ACK codebook of the PUCCH can include the HARQ-ACK bit(s) corresponding to the PDSCH received in slot n-k1_0, slot n-k1_1, slot n-k1_2, and slot n-k1_3.

[0431] Reference Figure 12a It can be assumed that k1_0=3 and k1_1=2 are configured as the K1 values for the UE. Accordingly, slot n-k1_0=n-3 and slot n-k1_1=n-2 are slots that need to be included in the HARQ-ACK codebook to be transmitted in slot n. The "slot to be included in the HARQ-ACK codebook" can mean that the HARQ-ACK information of the PDSCH received in the slot needs to be included in the HARQ-ACK codebook.

[0432] For reference, the PDSCH can be repeatedly transmitted over multiple slots. In this case, the embodiments of the present disclosure can be applied based on the last transmitted PDSCH.

[0433] Reference Figure 12a The maximum number of PDSCHs (second information) that the UE can receive in one slot can be N=2. In this case, the UE can receive scheduling of N=2 PDSCHs in one slot. For example, the UE can receive scheduling of PDSCH#1 and PDSCH#2 in slot n-3, and can receive scheduling of PDSCH#3 and PDSCH#4 in slot n-2. This example is for illustration, and the UE can receive scheduling of only one PDSCH in each slot, or can not receive scheduling of any PDSCH. Further, when the UE receives scheduling of N=2 or more PDSCHs in one slot, the UE can also determine the N PDSCHs to be received by using the first embodiment.

[0434] There can be N PDSCH occasions in each slot. N is the maximum number of PDSCHs to be processed in one slot determined according to the second information. That is, up to N PDSCHs can be scheduled in each slot. Accordingly, each slot can include N HARQ-ACK bits corresponding to the N PDSCHs of each slot. For example, slot n-k1_0 can include n HARQ-ACK bits, which are assumed to be b 0 0, b 0 1,..., b 0 N-1 Slot n-k1_1 can include N HARQ-ACK bits, which are assumed to be b 1 0, b 1 1,..., b 1 N-1 Slot n-k1_2 can include N HARQ-ACK bits, which are assumed to be b 2 0, b 2 1,..., b 2 N-1 Slot n-k1_3 can include N HARQ-ACK bits, which are assumed to be b 3 0, b 3 1,..., b 3 N-1 Accordingly, the HARQ-ACK codebook included in the PUCCH of slot n is [b 0 0, b 0 1,..., b 0 N-1 , b 1 0, b 1 1,..., b 1 N-1 , b 2 0, b 2 1,..., b 2 N-1 , b 3 0, b 3 1,..., b 3 N-1 The size (payload size) of the HARQ-ACK codebook can be equal to the product of the total number of K1 values included in the K1 set and the maximum number (N) of PDSCHs to be processed in one slot.

[0435] For reference, this is for one cell. When multiple cells are configured for a UE, the UE can generate a HARQ-ACK codebook for each cell and combine the codebooks in an ascending order of cell index to generate a single HARQ-ACK codebook. For reference, when multiple cells are configured, different K1 values can be configured for the respective cells, and different N values can be configured for the respective cells.

[0436] For reference, a base station can configure a UE with a maximum number of PDSCHs to be processed in one cell for multiple cells. For example, the number of cells configured for the UE can be A, and a maximum number of PDSCHs to be processed in one slot of A cells can be configured as N. In this case, the UE can generate N PDSCH occasions in one slot of A cells. The UE can receive a PDSCH in one slot of one of A cells. The received PDSCH can correspond to one of N PDSCH occasions. Here, each of the N PDSCH occasions can have no constraint on the cell to which (corresponding to) the PDSCH occasion belongs. That is, the PDSCH occasion can correspond to a PDSCH received in a first cell or a PDSCH received in a second cell.

[0437] For reference, a base station can configure a UE with a maximum number of PDSCHs to be processed in one slot for a plurality of cell sets. That is, a first maximum number of PDSCHs can be configured for a first cell set, and a second maximum number of PDSCHs can be configured for a second cell set. In this case, the UE can generate a first HARQ-ACK codebook for cells included in the first cell set based on the first maximum number of PDSCHs, can generate a second HARQ-ACK codebook for cells included in the second cell set based on the second maximum number of PDSCHs, and can combine the first HARQ-ACK codebook and the second HARQ-ACK codebook to generate a HARQ-ACK codebook.

[0438] Reference Figure 12b Since the number of PDSCHs to be processed in one slot is 2 (N=2), the UE can generate two PDSCH occasions for each slot corresponding to a K1 value. Since the K1 values are 3 and 2, the UE can generate a first PDSCH occasion and a second PDSCH occasion for slot n-3, and can generate a third PDSCH occasion and a fourth PDSCH occasion for slot n-2. In addition, each PDSCH occasion can have a corresponding HARQ-ACK bit. Thus, there can be four HARQ-ACK bits corresponding to the four PDSCH occasions, respectively. 0 0, b 0 1, b 1 0, b1 1]。Here, b 0 0 and b 0 1 are HARQ-ACK bits for the first PDSCH occasion and the second PDSCH occasion of slot n-3, and b 1 0 and b 1 1 are HARQ-ACK bits for the third PDSCH occasion and the fourth PDSCH occasion of slot n-2.

[0439] The UE needs to determine which one of the N PDSCH occasions the PDSCH received in a slot corresponds to. For example, when the UE receives a PDSCH in slot n-k1_0, the UE needs to determine which one of the N PDSCH occasions of the slot (and which one of the N HARQ-ACK bits corresponding to the N PDSCH occasions {b 0 0, b 0 1, b 0 2, b 0 3} the PDSCH received in the slot corresponds to. The UE can determine the PDSCH occasion corresponding to the received PDSCH by at least one of the following methods.

[0440] The UE can be indicated, in the DCI scheduling the PDSCH, an index of the PDSCH occasion corresponding to the scheduled PDSCH. More specifically, the DCI scheduling the PDSCH can include a field indicating the index of the PDSCH occasion. The length of the field can be determined as log2(N) bits. The UE can obtain, from the field of the DCI scheduling the PDSCH, the index of the PDSCH occasion corresponding to the scheduled PDSCH. For example, when N=4, the length of the field can be determined as 2 bits. When the 2 bits are 00, the index of the corresponding PDSCH occasion is 0; when the 2 bits are 01, the index of the corresponding PDSCH occasion is 1; when the 2 bits are 10, the index of the corresponding PDSCH occasion is 2; and when the 2 bits are 11, the index of the corresponding PDSCH occasion is 3. For reference, when N=1, the DCI can not include the field (i.e., the length of the field is 0 bit). In this case, the index of the PDSCH occasion corresponding to the scheduled PDSCH can be 0.

[0441] This field can not be included in the DCI scheduling the PDSCH. For example, in DCI format 1_1, 1_2, or 1_3, this field can be included in the DCI, but in DCI format 1_0, this field can not be included. (For reference, when a UE monitors DCI format 1_0 in a common search space, DCI format 1_0 can not include this field, and when a UE monitors DCI format 1_0 in a UE-specific search space, DCI format 1_0 can not include this field.) In addition, to reduce the overhead of DCI, the base station can not configure this field, which can be configured separately for each DCI format. Accordingly, this field can not be included in one or more of DCI formats 1_1, 1_2, and 1_3. In this case, the index of the PDSCH occasion corresponding to the scheduled PDSCH can be determined by at least one of the following methods.

[0442] According to a first method, for a PDSCH scheduled by DCI not including this field, the UE can always assume a specific index. For example, the UE can assume that the index of the PDSCH scheduled by DCI not including this field is 0. In another example, the UE can assume that the index of the PDSCH scheduled by DCI not including this field is N-1. In yet another example, the base station can configure the UE with an assumed index. That is, the index of the PDSCH scheduled by DCI not including this field is a specific index (e.g., index 2) configured by the base station.

[0443] According to a second method, the index can be determined according to time domain resource allocation information about the scheduled PDSCH. For example, the DCI can include a field indicating time domain allocation information about the PDSCH. This field can be referred to as a time domain resource assignment (TDRA) field. The TDRA field can include a TDRA table index. An entry of a TDRA table corresponding to the TDRA table index includes information about a slot or symbol in which the PDSCH is scheduled. The UE can obtain or calculate the index of the PDSCH occasion based on the indicated TDRA table index. For example, when the TDRA table index indicated in the DCI is i, the index of the corresponding PDSCH occasion can be determined as (i mod N) or ((i-1) mod N). (i mod N) can be used when the TDRA table index starts from 0, and ((i-1) mod N) can be used when the TDRA table index starts from 1.

[0444] According to a third method, the index can be determined according to a symbol index of the scheduled PDSCH. For example, the UE can determine the symbol index based on one symbol of the scheduled PDSCH. For example, the UE can determine the symbol index based on an index of a first symbol of the PDSCH or an index of a last symbol of the PDSCH. The symbol index is an index of a symbol in a slot, where a first symbol of the slot is 0 and a last symbol of the slot is 13. When the symbol index of the PDSCH scheduled for the UE is i, the index of the corresponding PDSCH occasion can be determined as (i mod N). According to another method, when the symbol index of the PDSCH scheduled for the UE is i, if i is included in a specific symbol index range, the index of the corresponding PDSCH occasion can be determined as a specific PDSCH occasion index. For example, when N is 4, if i is included in a symbol index range of {0 to A0}, the index of the corresponding PDSCH occasion can be 0, if i is included in a symbol index range of {A0+1 to A1}, the index of the corresponding PDSCH occasion can be 1, if i is included in a symbol index range of {A1+1 to A2}, the index of the corresponding PDSCH occasion can be 2, and if i is included in a symbol index range of {A2+1 to 13}, the index of the corresponding PDSCH occasion can be 3. Here, it can be satisfied that 0≤A0<A1<A2≤13. Here, it can be satisfied that A0=3, A1=6, and A2=10; A0=2, A1=6, and A2=9; A0=3, A1=6, and A2=9; or A0=2, A1=6, and A2=10. In addition, A0, A1, and A2 can be configured by the base station for the UE.

[0445] According to a fourth method, the index can be determined according to information about a time at which scheduling DCI is transmitted. For example, the UE can determine the index of the PDSCH occasion corresponding to the PDSCH scheduled by the DCI based on an index of a slot in which the DCI scheduling the PDSCH is transmitted. Here, the scheduling DCI can be transmitted through a PDCCH. The index of the slot in which the DCI is transmitted refers to a slot in which the PDCCH including the DCI is received. When the index of the slot is i, the index of the corresponding PDSCH occasion can be determined as (i mod N). That is, the base station can schedule PDSCHs through DCIs transmitted in different slots, thereby determining PDSCH occasion indexes of the respective PDSCHs to be different.

[0446] According to a fifth method, the index of the PDSCH occasion can be determined according to information on a frequency in which the scheduling DCI is transmitted. For example, the UE can determine the index of the PDSCH occasion corresponding to the PDSCH scheduled by the DCI based on the index of the CCE mapped to the PDCCH including the DCI scheduling the PDSCH. Here, one CCE or a plurality of CCEs can be mapped to the PDCCH. When a plurality of CCEs are mapped, the CCE having the lowest index can be used. When the index of the CCE is i, the UE can determine the index of the corresponding PDSCH occasion as (i mod N). That is, the base station can schedule the PDSCH through the DCI transmitted in different CCEs, thereby determining the PDSCH occasion index of the corresponding PDSCH to be different.

[0447] According to a sixth method, the index of the PDSCH occasion can be determined according to the index of the CORESET or search space in which the scheduling DCI is transmitted. For example, the UE can determine the index of the PDSCH occasion corresponding to the PDSCH scheduled by the DCI based on the index of the CCE mapped to the PDCCH including the DCI scheduling the PDSCH, based on the index of the CORESET or search space in which the PDCCH including the DCI scheduling the PDSCH is monitored. For reference, the PDCCH can be repeatedly transmitted in two linked search spaces. In this case, the index of the PDSCH occasion can be determined based on one search space (e.g., the search space having a low index). When the index of the CORESET or search space is i, the UE can determine the index of the corresponding PDSCH occasion as (i mod N). That is, the base station can schedule the PDSCH through the DCI transmitted in different CORESETs or search spaces, thereby determining the PDSCH occasion index of the corresponding PDSCH to be different.

[0448] According to a seventh method, the index of the PDSCH occasion can be determined based on the value of the HARQ process number field of the scheduling DCI. The DCI scheduling the PDSCH can include a field indicating the HARQ process number of the scheduled PDSCH. The UE can obtain the HARQ process number of the scheduled PDSCH based on the field. When the HARQ process number identified by the UE is i, the index of the corresponding PDSCH occasion can be determined as (i mod N). That is, the base station can schedule the PDSCH through the DCI in which different HARQ process numbers are configured, thereby determining the PDSCH occasion index of the corresponding PDSCH to be different. Although described using the HARQ process number field, the index of the PDSCH occasion can be determined based on the value of other fields included in the DCI, for example, the TPC command, MCS, and RV fields for the PUCCH.

[0449] A UE can be configured to receive SPS PDSCHs in slots. HARQ-ACK bits for SPS PDSCHs can be included in a HARQ-ACK codebook. To include HARQ-ACK bits for SPS PDSCHs in a HARQ-ACK codebook, the UE needs to determine the indices of PDSCH occasions corresponding to SPS PDSCHs. The following methods can be used.

[0450] According to a first method, the indices of PDSCH occasions can be configured in an SPS PDSCH configuration. The UE can receive the SPS PDSCH configuration through an upper layer signal (RRC signal) of the base station. The indices of PDSCH occasions corresponding to SPS PDSCHs received according to the SPS PDSCH configuration can always be the configured indices.

[0451] According to a second method, the indices of PDSCH occasions can be indicated in DCI activating SPS PDSCHs. For example, a field indicating the indices of corresponding PDSCH occasions can be included in DCI activating SPS PDSCHs. The indices of PDSCH occasions indicated in the field can be commonly applied to all SPS PDSCHs activated by the DCI. For reference, when the field is not present in DCI activating SPS PDSCHs, the UE can obtain or calculate the indices of PDSCH occasions corresponding to SPS PDSCHs by using the aforementioned method for the case where the field is not included for DCI.

[0452] Reference Figure 12b , the UE can determine the correspondence between received PDSCHs and PDSCH occasions based on the indices of received PDSCHs. For example, the index of PDSCH #1 received in slot n-3 can be 0, and the index of PDSCH #2 received in slot n-3 can be 1. The two received PDSCHs can correspond to two PDSCH occasions (a first PDSCH occasion and a second PDSCH occasion) included in slot n-3, respectively. PDSCH #1 having a lower index can correspond to the first PDSCH occasion, and PDSCH #2 having a higher index can correspond to the second PDSCH occasion. The index of PDSCH #3 received in slot n-2 can be 0, and the index of PDSCH #4 received in slot n-2 can be 1. The two received PDSCHs can correspond to two PDSCH occasions (a third PDSCH occasion and a fourth PDSCH occasion) included in slot n-2, respectively. PDSCH #3 having a lower index can correspond to the third PDSCH occasion, and PDSCH #4 having a higher index can correspond to the fourth PDSCH occasion.

[0453] Figure 13A case in which a UE according to an embodiment of the disclosure receives two or more PDSCHs having the same index in one slot is shown.

[0454] Referring to Figure 13 , the UE can receive scheduling of three PDSCHs in one slot. For reference, it can be assumed that the UE has a UE capability of processing three or more PDSCHs in one slot. However, the base station can configure a number smaller than 3 (e.g., N=2) as the second information. Two of the three PDSCHs (PDSCH#1 and PDSCH#2) can have the same index 0, and the other PDSCH (PDSCH#3) can have an index 1. The HARQ-ACK codebook according to the UE capability can include two PDSCH occasions because N=2. In this case, the UE needs to determine how the two PDSCHs (PDSCH#1 and PDSCH#2) having the same index correspond to the PDSCH occasions.

[0455] The UE can receive scheduling of only one PDSCH corresponding to one PDSCH occasion. That is, when two or more PDSCHs correspond to a PDSCH occasion, the UE can consider this case as an error.

[0456] When a plurality of PDSCHs correspond to one PDSCH occasion, the UE can generate a HARQ-ACK bit corresponding to the PDSCH occasion by at least one of the following methods.

[0457] Referring to Figure 13a, According to the first method, the UE can select one of the plurality of PDSCHs. When generating the HARQ-ACK codebook, the UE can include the HARQ-ACK bit of the selected PDSCH in the location of the HARQ-ACK bit of the corresponding PDSCH occasion. For example, the UE can select a PDSCH from among the plurality of PDSCHs based on time (location of the scheduled symbol). The UE can select a PDSCH that is first in time (first scheduled symbol). For example, the UE can select a PDSCH that is last scheduled. That is, the UE can select a PDSCH corresponding to the last received DCI among DCIs scheduling the plurality of PDSCHs. For example, the UE can select a PDSCH scheduled by a DCI among the plurality of PDSCHs. That is, when a PDSCH scheduled by a DCI and an SPS PDSCH correspond to the same PDSCH occasion, the UE can select the PDSCH scheduled by the DCI. For example, the UE can select one PDSCH based on the HARQ process number value of the plurality of PDSCHs. That is, the UE can select a PDSCH having the lowest HARQ process number value. For example, when the plurality of PDSCHs are SPS PDSCHs, the UE can select a PDSCH based on the index of the SPS PDSCH (included in the SPS PDSCH configuration information). That is, the UE can select an SPS PDSCH having the lowest index.

[0458] Reference Figure 13 b, According to the second method, when all PDSCHs corresponding to one PDSCH occasion are successfully received, the UE can include an ACK in the HARQ-ACK codebook having the corresponding HARQ-ACK bit, and when at least one of the PDSCHs corresponding to one PDSCH occasion is not received, the UE can include a NACK in the HARQ-ACK codebook having the corresponding HARQ-ACK bit. That is, the UE can obtain or calculate the HARQ-ACK bits of the PDSCHs corresponding to one PDSCH occasion, and can subject the HARQ-ACK bits to binary bundling to generate a single HARQ-ACK bit. Here, binary bundling can refer to an operation of determining an ACK when all HARQ-ACK bits are ACK and determining a NACK otherwise.

[0459] In the second method, the UE receives all PDSCHs corresponding to one PDSCH occasion and generates a corresponding HARQ-ACK bit. According to the first method, the UE can receive some of the PDSCHs corresponding to one PDSCH occasion and can include ACK in a HARQ-ACK codebook having a HARQ-ACK bit corresponding to one PDSCH occasion of the some PDSCHs when the some PDSCHs are successfully received. In addition, when at least one of the some PDSCHs fails to be received, the UE can include NACK in the HARQ-ACK codebook having the HARQ-ACK bit corresponding to one PDSCH occasion of the some PDSCHs.

[0460] Reference Figure 13 c. According to the third method, when a plurality of PDSCHs correspond to one PDSCH occasion, the UE can include NACK in a HARQ-ACK codebook having a HARQ-ACK bit of the PDSCH occasion. That is, when a plurality of PDSCHs correspond to one PDSCH occasion, the UE can not receive the plurality of PDSCHs and can generate NACK.

[0461] Figure 14 The change of the HARQ-ACK codebook according to the maximum number of PDSCHs to be processed in one slot according to an embodiment of the disclosure is illustrated.

[0462] It is assumed that the maximum number of PDSCHs that the UE can process in one slot is a number greater than or equal to 2. In this case, the base station can indicate 1 or 2 to the UE as the maximum number of PDSCHs to be processed in one slot. Reference Figure 14 When the base station schedules one PDSCH for each slot for the UE and indicates to the UE that the maximum number of PDSCHs to be processed in one slot is 2, the UE can generate two PDSCH occasions per slot. In the HARQ-ACK codebook, two HARQ-ACK bits per slot are included. However, when the maximum number of PDSCHs to be processed is indicated to the UE as 2, the UE generates one PDSCH occasion per slot. Therefore, the HARQ-ACK codebook includes only one HARQ-ACK bit per slot. Thus, when the maximum number of PDSCHs to be processed is indicated to the UE according to the number of actually scheduled PDSCHs, the UE can more efficiently generate the HARQ-ACK codebook.

[0463] The size of the HARQ-ACK codebook is determined according to the configuration (second information) of the maximum number of PDSCHs to be processed in one slot. The base station can change the maximum number of PDSCHs to be processed in one slot due to UE traffic information and scheduler implementation. The change can be forwarded through DCI, MAC-CE, or RRC signal.

[0464] When the change is forwarded through DCI, the size can be determined through at least one of the following two methods.

[0465] According to the first method, the DCI scheduling the PDSCH can include the configuration of the maximum number of PDSCHs to be processed in one slot. The UE can receive the configuration of the maximum number of PDSCHs to be processed in one slot through the DCI scheduling the PDSCH, and can generate the HARQ-ACK codebook based on the value. The UE can expect that the same value is always configured in the DCI scheduling the PDSCH corresponding to the same HARQ-ACK codebook. That is, the base station needs to include the same value (the maximum number of PDSCHs to be processed in one slot) in the DCI scheduling the PDSCH corresponding to the same HARQ-ACK codebook. The UE can receive at least one DCI, thereby determining the size of the HARQ-ACK codebook corresponding to the HARQ-ACK bit of the PDSCH scheduled by the DCI.

[0466] Information on the configuration of the maximum number of PDSCHs to be processed in one slot in the DCI can be included as follows.

[0467] The DCI can include a 1-bit field. When the 1-bit is "0", the UE can be scheduled with up to one PDSCH in one slot. When the 1-bit is "1", the maximum number of PDSCHs that can be scheduled for the UE in one slot can be a value configured in an upper layer signal (RRC signal) or a value determined according to the UE capability.

[0468] The DCI can include a 1-bit field. When the 1-bit is "0", a first value can be determined as the maximum number of PDSCHs that can be scheduled in one slot. When the 1-bit is "1", a second value can be determined as the maximum number of PDSCHs that can be scheduled in one slot. The first value and the second value can be two values among 1, 2, 4, and 7. In another example, the base station can configure values corresponding to the first value and the second value for the UE.

[0469] The DCI can include a 2-bit field. When the 2 bits are '00', the UE can generate a HARQ-ACK codebook for the currently scheduled PDSCH using the maximum number of PDSCHs schedulable in one slot for the previous HARQ-ACK codebook. That is, the same size as that of the previous HARQ-ACK codebook can be maintained. When the 2 bits are '01', the UE can generate a HARQ-ACK codebook for the currently scheduled PDSCH using a number smaller than the maximum number of PDSCHs schedulable in one slot for the previous HARQ-ACK codebook. That is, the UE can generate a HARQ-ACK codebook having a smaller size than the previous HARQ-ACK codebook. When the 2 bits are '10', the UE can generate a HARQ-ACK codebook for the currently scheduled PDSCH using a number greater than the maximum number of PDSCHs schedulable in one slot for the previous HARQ-ACK codebook. That is, the UE can generate a HARQ-ACK codebook having a larger size than the previous HARQ-ACK codebook. Here, the smaller number and the greater number can be numbers reduced or increased by 1, or can be predetermined values. For example, the maximum number of PDSCHs schedulable in one slot can be determined as one value among {1, 2, 4, 7}.

[0470] The DCI can include a 2-bit field. When the 2 bits are '00', the UE can determine a first value as the maximum number of PDSCHs schedulable in one slot. When the 2 bits are '01', the UE can determine a second value as the maximum number of PDSCHs schedulable in one slot. When the 2 bits are '10', the UE can determine a third value as the maximum number of PDSCHs schedulable in one slot. When the 2 bits are '11', the UE can determine a fourth value as the maximum number of PDSCHs schedulable in one slot. Here, the first value, the second value, the third value, and the fourth value can be 1, 2, 4, and 7, respectively. In another example, the base station can configure values corresponding to the first value, the second value, the third value, and the fourth value for the UE.

[0471] According to the second method, the DCI not scheduling the PDSCH can include the maximum number of PDSCHs to be processed in one slot. The UE can transmit HARQ-ACK information to the base station in response to the DCI, and after a specific time point after the transmission, the UE can generate a HARQ-ACK codebook based on the maximum number of PDSCHs to be processed in one slot included in the DCI. The maximum number of PDSCHs to be processed in one slot included in the DCI can not be applied before the specific time point. Here, the specific time point can be the first slot after a predetermined time (e.g., 3 ms) from a symbol or a slot in which the HARQ-ACK information is transmitted in response to the DCI.

[0472] According to an embodiment of the disclosure, a UE can reduce the size of a HARQ-ACK codebook according to a UE capability. The UE can reduce the size of the codebook based on a time domain resource assignment (TDRA) table and a TDD configuration.

[0473] The TDD configuration includes types of symbols configured for the UE by a base station through a system information block (SIB) or an RRC signal. The symbols can be configured as one of a downlink symbol, an uplink symbol, and a flexible symbol. The downlink symbol is a symbol in which downlink reception is possible and uplink transmission is not possible for the UE. The uplink symbol is a symbol in which uplink transmission is possible and downlink reception is not possible for the UE. The flexible symbol is a symbol in which downlink reception or uplink transmission is possible for the UE.

[0474] The UE can determine whether to include a HARQ-ACK bit in a HARQ-ACK codebook based on a symbol type of a slot for transmitting the HARQ-ACK bit of the UE. For example, when all slots for transmitting the HARQ-ACK bit are configured as uplink symbols, the UE cannot receive a PDSCH in the slots. Accordingly, the UE can exclude the HARQ-ACK bit for the slots from the HARQ-ACK codebook.

[0475] The UE can determine whether to include a HARQ-ACK bit in a HARQ-ACK codebook based on a symbol type of a slot for transmitting the HARQ-ACK bit of the UE and a TDRA table configuration. The TDRA table can include one or more start and length indication values (SLIVs) indicating symbols in which the UE can receive a PDSCH in the slot. The UE can determine whether each SLIV of the TDRA table overlaps with an uplink symbol. When all SLIVs overlap with the uplink symbol, the UE can not be scheduled with a PDSCH in the slot. Accordingly, the UE can exclude the HARQ-ACK bit for the slot from the HARQ-ACK codebook.

[0476] The UE configured to use a HARQ-ACK codebook according to a UE capability can change a method for including a HARQ-ACK bit of a slot of the HARQ-ACK codebook based on a TDRA table configuration. The method for including the HARQ-ACK bit of the UE can be at least one of the following methods.

[0477] - The first method is that a UE according to a second embodiment of the disclosure includes HARQ-ACK bits for N PDSCH occasions of a slot. Here, N is the maximum number of PDSCHs that the UE can process in one slot. Accordingly, the UE can include N HARQ-ACK bits for one slot. (Here, it is assumed that one PDSCH occasion corresponds to 1 HARQ-ACK bit. When one PDSCH occasion corresponds to a plurality of HARQ-ACK bits, different HARQ-ACK bits can be used instead of N HARQ-ACK bits.)

[0478] - The second method is that the UE includes HARQ-ACK bits for a slot based on the SLIV of the TDRA table as in the Type 1 HARQ-ACK codebook. More specifically, the UE allocates one HARQ-ACK bit to the bundle of the SLIV in which the ending symbol is the earliest in time among the SLIVs of the TDRA table and the SLIVs overlapping the SLIV. Then, the UE excludes the SLIV from the TDRA table. For the remaining SLIVs, the UE can continue to allocate one HARQ-ACK bit to the bundle of the SLIV in which the ending symbol is the earliest in time among the SLIVs of the TDRA table and the SLIVs overlapping the SLIV. Then, the UE excludes the SLIV from the TDRA table. This process can be continued until there is no SLIV in the TDRA table. For example, the SLIVs overlapping the uplink symbols among the SLIVs included in the TDRA table can be excluded from the TDRA table first.

[0479] The UE can include the HARQ-ACK bits by selecting one of the first method and the second method for each slot. For example, when the number of HARQ-ACK bits in a slot is determined to be smaller through one of the first method and the second method, the UE can generate the HARQ-ACK bits for the slot by using the one method.

[0480] Figure 15 is a flowchart of generating a HARQ-ACK codebook according to a UE capability according to an embodiment of the disclosure.

[0481] In the first step 1500, the UE can receive K1 value configuration information and configuration of the maximum number N of PDSCHs to be processed in one slot from the base station. In this case, when the base station does not configure the maximum number of PDSCHs to be processed in one slot for the UE, the UE can assume the maximum number of PDSCHs to be processed in one slot determined according to the UE capability.

[0482] In the second step 1510, the UE can determine a slot corresponding to a configured K1 value, and can generate N PDSCH occasions per slot. The UE can generate a HARQ-ACK bit corresponding to each generated PDSCH occasion. When an index of a slot in which a HARQ-ACK is transmitted is slot n, a slot corresponding to a configured K1 value (K1) can be determined as slot n-k1.

[0483] In the third step 1520, the UE can determine a PDSCH occasion corresponding to a PDSCH received in a slot corresponding to a configured K1 value. For a correspondence relationship, an index can be assigned to a received PDSCH, and there can be a PDSCH occasion corresponding to each index. Here, the index can be one of 0, 1,..., and N-1.

[0484] In the fourth step 1530, the UE can include HARQ-ACK information (ACK or NACK) on a received PDSCH in a HARQ-ACK bit of a determined PDSCH occasion. When a PDSCH corresponding to a PDSCH occasion is not received, the UE can indicate HARQ-ACK information on the PDSCH occasion as 0.

[0485] In the fifth step 1540, the UE can transmit a HARQ-ACK codebook including a HARQ-ACK bit for a generated PDSCH occasion to a base station. The codebook can be transmitted through a PUCCH or a PUSCH.

[0486] [Third Embodiment: Compact Type 1 HARQ-ACK Codebook Method]

[0487] To reduce the size of a type 1 HARQ-ACK codebook, a base station can configure a UE with a virtual TDRA table for determining the number of HARQ-ACK bits. The virtual TDRA table can include SLIVs. The virtual TDRA table is configured to determine the number of HARQ-ACK bits of a type 1 HARQ-ACK codebook, and can be different from a TDRA table for actual scheduling.

[0488] For reference, the virtual TDRA table can include only some of the SLIVs of the TDRA table for actual scheduling. That is, the SLIV included in the virtual TDRA table is one of the SLIVs of the TDRA table for actual scheduling. Accordingly, the base station can configure the UE with an index of the actual TDRA table, thereby configuring the SLIV included in the virtual TDRA table.

[0489] The UE can determine the number of HARQ-ACK bits for one slot based on the SLIVs of the virtual TDRA table. More specifically, the UE allocates one HARQ-ACK bit to a bundle of the SLIVs in which the ending symbol is earliest in time among the SLIVs of the virtual TDRA table and overlaps with the SLIV. Then, the UE excludes the SLIVs from the virtual TDRA table. For the remaining SLIVs, the UE can continue to allocate one HARQ-ACK bit to a bundle of the SLIVs in which the ending symbol is earliest in time among the SLIVs and overlaps with the SLIV. Then, the UE excludes the SLIVs from the virtual TDRA table. The process can continue until there is no SLIV in the TDRA table. For example, the SLIVs overlapping with the uplink symbols of the SLIVs included in the virtual TDRA table can be excluded from the TDRA table first.

[0490] The UE can determine the correspondence between the SLIVs of the TDRA table to be used for actual scheduling and the HARQ-ACK bits. For example, the UE can select a first SLIV (earliest in ending symbol) among the SLIVs of the virtual TDRA table overlapping with the SLIVs of the TDRA table to be used for actual scheduling (hereinafter, actual SLIVs), and can determine the HARQ-ACK bit corresponding to the selected SLIV as a bit for transmitting the HARQ-ACK information for the PDSCH scheduled with the actual SLIV.

[0491] For reference, when the UE is configured with the virtual TDRA table, the base station can configure the virtual TDRA table such that the SLIVs of the virtual TDRA table do not overlap in symbols. In this configuration, when the UE obtains or calculates the HARQ-ACK bits based on the virtual TDRA table, the UE can not perform the operation of determining and excluding the overlapping SLIVs. That is, the implementation complexity of the UE can be reduced.

[0492] For reference, when the UE is configured with the virtual TDRA table, the base station can configure the virtual TDRA table such that the SLIVs of the virtual TDRA table include all symbols of a slot. That is, each symbol of the slot can overlap with at least one SLIV.

[0493] The UE configured to use the type 1 HARQ-ACK codebook can change the method for including the HARQ-ACK bits for a slot including the HARQ-ACK codebook based on the maximum number of PDSCHs to be processed in one slot. The method by which the UE includes the HARQ-ACK bits can be at least one of the following methods.

[0494] - The first method is that the UE according to the second embodiment of the disclosure includes HARQ-ACK bits for N PDSCH occasions of a slot. Here, N is the maximum number of PDSCHs that the UE can process in one slot. Thus, the UE can include N HARQ-ACK bits for one slot. (Here, it is assumed that one PDSCH occasion corresponds to 1 HARQ-ACK bit. When one PDSCH occasion corresponds to multiple HARQ-ACK bits, different HARQ-ACK bits can be used instead of N HARQ-ACK bits.)

[0495] - The second method is that the UE includes HARQ-ACK bits for a slot based on the SLIVs of the TDRA table as in the Type 1 HARQ-ACK codebook. More specifically, the UE allocates one HARQ-ACK bit to the bundle of the SLIV in which the ending symbol is the earliest in time among the SLIVs of the TDRA table and the SLIVs overlapping with the SLIV. Then, the UE excludes the SLIV from the TDRA table. For the remaining SLIVs, the UE can continue to allocate one HARQ-ACK bit to the bundle of the SLIV in which the ending symbol is the earliest in time among the SLIVs of the TDRA table and the SLIVs overlapping with the SLIV. Then, the UE excludes the SLIV from the TDRA table. This process can continue until there is no SLIV in the TDRA table. For example, the SLIVs overlapping with the uplink symbols among the SLIVs included in the TDRA table can be excluded from the TDRA table first.

[0496] The UE can include HARQ-ACK bits in the HARQ-ACK codebook by selecting one of the first method and the second method for each slot. For example, when the number of HARQ-ACK bits in a slot is less by one of the first method and the second method, the UE can generate the HARQ-ACK bits for the slot by using the one method.

[0497] [Fourth Embodiment: Method for determining HARQ-ACK codebook type]

[0498] The UE can support the design of two or more HARQ-ACK codebooks. For example, the UE can generate the following two HARQ-ACK codebooks at the same time.

[0499] - The first HARQ-ACK codebook is a HARQ-ACK codebook according to UE capability (second embodiment)

[0500] - The second HARQ-ACK codebook is a Type 3 HARQ-ACK codebook

[0501] For reference, two HARQ-ACK codebooks are used for illustration, and embodiments of the present disclosure can be applied to other HARQ-ACK codebooks. In addition, although described with reference to two HARQ-ACK codebooks for convenience of description, embodiments of the present disclosure can be applied to two or more HARQ-ACK codebooks (for example, the embodiments can be equally applied to three HARQ-ACK codebooks).

[0502] A type 3 HARQ-ACK codebook (or one-shot codebook) is a method for a UE to report all HARQ-ACK information about the number of serving cells and HARQ processes configured for the UE, the number of TBs per HARQ process, and the number of CBGs per TB. For example, when the UE has two serving cells, 16 HARQ processes per serving cell, one TB per HARQ process, and two CBGs per TB, the UE can report a total of 64 (=2 16 1 2) HARQ-ACK information bits.

[0503] The type 3 HARQ-ACK codebook can enumerate the HARQ-ACK information bits according to a sequence. The sequence is as follows.

[0504] - The bits can be arranged in ascending order of the index of the serving cell.

[0505] - Within the same serving cell, the bits can be arranged in ascending order of the HARQ process.

[0506] - When multiple TBs are included in the same HARQ process (i.e., in the case of 2-TB transmission), the HARQ-ACK information about the first TB can be arranged in a position before the HARQ-ACK information about the second TB.

[0507] - When multiple CBGs are included in the same TB (i.e., in the case of CBG-based PDSCH transmission), the bits can be arranged in ascending order of the index of the CBG.

[0508] According to embodiments of the present disclosure, the UE can determine the length of each HARQ-ACK codebook. For example, in the case of the first HARQ-ACK codebook, the length of the HARQ-ACK codebook can be {the number of slots corresponding to the K1 value The maximum number of PDSCHs to be processed in a slot. For reference, the number of slots corresponding to the K1 value can vary depending on the TDD configuration information. In the case of the second HARQ-ACK codebook, the length of the HARQ-ACK codebook can be equal to the number of configured HARQ process numbers.

[0509] The UE can compare the lengths of the two HARQ-ACK codebooks. When the length of the first HARQ-ACK codebook is shorter than the length of the second HARQ-ACK codebook, the UE can select the first HARQ-ACK codebook. When the length of the second HARQ-ACK codebook is shorter than the length of the first HARQ-ACK codebook, the UE can select the second HARQ-ACK codebook. That is, when the UE is able to generate two or more HARQ-ACK codebooks, the UE can select one of the HARQ-ACK codebooks based on the lengths of the HARQ-ACK codebooks.

[0510] The UE can transmit the selected HARQ-ACK codebook to the base station. The HARQ-ACK codebook can be transmitted through a PUCCH or a PUSCH.

[0511] By selecting the HARQ-ACK codebook having a shorter length and transmitting the codebook to the base station, the UE can reduce uplink resource overhead. For reference, the base station can know the length of the HARQ-ACK codebook to be generated by the UE. Accordingly, the base station can know in advance which HARQ-ACK codebook the UE is to transmit.

[0512] According to an embodiment of the disclosure, the type of the HARQ-ACK codebook to be used by the UE can be indicated through DCI. More specifically, the base station can configure the types of the HARQ-ACK codebooks available to the UE. In addition, the UE can receive an indication of the type of the HARQ-ACK codebook to be used from the DCI. For example, when the base station configures the first HARQ-ACK codebook and the second HARQ-ACK codebook for the UE, the DCI can include a field for selecting one of the two codebooks. The UE can generate the HARQ-ACK codebook based on the field. For reference, the DCI can be a DCI format for scheduling a PDSCH.

[0513] Figure 16 is a flowchart of selecting a HARQ-ACK codebook type according to an embodiment of the disclosure.

[0514] In the first step 1600, the UE can calculate the number of HARQ-ACK bits included in the HARQ-ACK codebook according to the first method or the first HARQ-ACK codebook configuration. In addition, the UE can calculate the number of HARQ-ACK bits included in the HARQ-ACK codebook according to the second method or the second HARQ-ACK codebook configuration.

[0515] In a second step 1610, the UE can compare the number of HARQ-ACK bits determined according to the two methods or two HARQ-ACK codebook configurations. The UE can select the method or the HARQ-ACK codebook configuration that provides a smaller number of HARQ-ACK bits among the number of HARQ-ACK bits determined according to the two methods or two HARQ-ACK codebook configurations.

[0516] In a third step 1620, the UE can generate a HARQ-ACK codebook according to the selected method or the selected HARQ-ACK codebook configuration, and can transmit the codebook to the base station.

[0517] Figure 17 A structure of a UE in a wireless communication system according to an embodiment of the disclosure is illustrated.

[0518] Reference Figure 17 The UE can include a transceiver (which collectively refers to a UE receiver 1700 and a UE transmitter 1710), a memory (not shown), and a UE processor 1705 (or a UE controller or a processor). The UE transceiver 1700 and 1710, the memory, and the UE processor 1705 can operate according to the above-described communication method of the UE. The components of the UE are not limited to the above-described examples. For example, the UE can include a greater or smaller number of components than the above-described components. Also, the transceiver, the memory, and the processor can be implemented in the form of a single chip.

[0519] The transceiver can transmit / receive a signal with a base station or other UEs. The signal can include control information and data. To this end, the transceiver can include an RF transmitter configured to perform amplification and frequency up-conversion of a transmitted signal, an RF receiver configured to perform low-noise amplification and frequency down-conversion of a received signal, and the like. However, this is only an embodiment of the transceiver, and the components of the transceiver are not limited to the RF transmitter and the RF receiver.

[0520] In addition, the transceiver can receive a signal through a radio channel, output it to the processor, and transmit a signal output from the processor through a radio channel.

[0521] The memory can store programs and data necessary for the operation of the UE. In addition, the memory can store control information or data included in a signal transmitted / received by the UE. The memory can include a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media. In addition, the memory can include a plurality of memories.

[0522] Furthermore, the processor can control a series of processes that enable the UE to operate according to the embodiments described above. For example, the processor can control components of the UE to receive DCIs configured in two layers to receive multiple PDSCHs simultaneously. The processor may include multiple processors, and the processors can perform operations to control the components of the UE by executing programs stored in memory.

[0523] Figure 18 The structure of a base station in a wireless communication system according to an embodiment of the present disclosure is shown.

[0524] refer to Figure 18 A base station may include transceivers (which generally refer to base station receiver 1800 and base station transmitter 1810), a memory (not shown), and a base station processor 1805 (or base station controller or processor). The base transceivers 1800 and 1810, the memory, and the base station processor 1805 may operate according to the communication methods described above for the base station. However, the components of a base station are not limited to the examples described above. For example, a base station may include more or fewer components than those described above. Furthermore, the transceivers, memory, and processor may be implemented as a single chip.

[0525] The transceiver can transmit / receive signals with the UE or other base stations. These signals may include control information and data. For this purpose, the transceiver may include an RF transmitter configured to perform amplification and frequency up-conversion of the transmitted signal, an RF receiver configured to perform low-noise amplification and frequency down-conversion of the received signal, and so on. However, this is only one embodiment of the transceiver, and the components of the transceiver are not limited to RF transmitters and RF receivers.

[0526] In addition, the transceiver can receive signals via a radio channel, output them to the processor, and transmit signals output from the processor via a radio channel.

[0527] The memory can store programs and data necessary for the operation of the base station. Additionally, the memory can store control information or data included in signals transmitted / received by the base station. The memory can include storage media such as ROM, RAM, hard disks, CD-ROMs, and DVDs, or combinations of storage media. Furthermore, the memory can include multiple memories.

[0528] The processor can control a series of processes that enable the base station to operate according to the embodiments of the present disclosure described above. For example, the processor can control components of the base station to configure and transmit a DCI configured in two layers, including allocation information regarding multiple PDSCHs. The processor may include multiple processors, and the processor can perform operations controlling the components of the base station by executing programs stored in memory.

[0529] The disclosure proposes a method of designing a HARQ-ACK codebook according to a UE capability.

[0530] The UE can report a maximum number of PDSCHs to be received (processed) per slot to the base station. The UE can generate a HARQ-ACK codebook based on the maximum number of PDSCHs.

[0531] The HARQ-ACK codebook transmitted in slot n can include as many HARQ-ACK bits as the maximum number of PDSCHs PDSCHs. Here, the b-th bit indicates HARQ-ACK information about the i-th PDSCH received in slot n-K1,k. Here, k=floor(n / number of configured K1 values), i=b-k configured K1 values, and K1,k is the k-th K1 value among the configured K1 values.

[0532] When the maximum number of PDSCHs that the UE can receive (process) per slot is greater than 2 (2, 4, or 7), the UE needs to determine the order of the PDSCH (i-th PDSCH) received in the slot. For this, the following method can be considered.

[0533] The DCI format scheduling the PDSCH can indicate the order of the PDSCH received in the slot. For example, when "0" is indicated, the PDSCH is determined as the 0-th PDSCH.

[0534] The order of the PDSCH can be determined based on time domain allocation information and / or frequency domain allocation information about the PDSCH. For example, when the starting symbol / RB of the received PDSCH is a specific index, the UE can determine the order of the PDSCH based on the specific index. Alternatively, when the number of symbols / RBs included in the received PDSCH is a specific number, the UE can determine the order of the PDSCH based on the specific number.

[0535] The method disclosed in the claims and / or the method according to the embodiments described in the specification of the disclosure can be implemented by hardware, software, or a combination of hardware and software.

[0536] When the method is implemented by software, a computer-readable storage medium for storing one or more programs (software modules) can be provided. The one or more programs stored in the computer-readable storage medium can be configured to be executed by one or more processors within an electronic device. The at least one program includes instructions that cause the electronic device to execute the methods according to various embodiments of the disclosure defined by the appended claims and / or disclosed herein.

[0537] These programs (software modules or software) can be stored in non-volatile memory including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), a magnetic disc storage device, an optical compact disc ROM (CD-ROM), a digital versatile disc (DVD), or other types of optical storage devices, or a magnetic cassette. Alternatively, any combination of some or all of them can form a memory that stores programs. In addition, a plurality of such memories can be included in an electronic device.

[0538] In addition, programs can be stored in an attachable storage device that can access an electronic device through a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WLAN), and a storage area network (SAN), or a combination thereof. Such a storage device can access an electronic device via an external port. In addition, a separate storage device on a communication network can access a portable electronic device.

[0539] In the above detailed embodiments of the disclosure, elements included in the disclosure are expressed in singular or plural according to the presented detailed embodiments. However, for ease of description, singular or plural is appropriately selected for the presented situation, and the disclosure is not limited by the elements expressed in singular or plural. Therefore, elements expressed in plural can also include a single element, or elements expressed in singular can also include a plurality of elements.

[0540] Embodiments of the disclosure described and illustrated in the specification and drawings are merely specific examples presented to easily explain the technical content of the disclosure and help understanding of the disclosure, and are not intended to limit the scope of the disclosure. That is, it will be apparent to those skilled in the art that other variations based on the technical idea of the disclosure can be implemented. In addition, the respective embodiments described above can be combined as needed. For example, a part of one embodiment of the disclosure can be combined with a part of another embodiment to operate a base station and a user equipment (UE). As an example, a part of a first embodiment of the disclosure can be combined with a part of a second embodiment to operate a base station and a UE. In addition, although the above-described embodiments have been described based on an FDD LTE system, other variations based on the technical idea of the embodiments can also be implemented in other communication systems such as a TDD LTE and a 5G or NR system.

[0541] In the drawings describing the method of the disclosure, the order described does not always correspond to the order of performing the steps, and the order relationship between the steps can be changed or the steps can be performed in parallel.

[0542] Alternatively, in the accompanying drawings that describe the method of the present disclosure, some elements can be omitted and only some elements can be included therein without departing from the essential spirit and scope of the present disclosure.

[0543] Further, in the method of the present disclosure, part or all of each embodiment can be implemented in combination without departing from the essential spirit and scope of the present disclosure.

[0544] Various embodiments of the present disclosure have been described above. The above description of the present disclosure is for the purpose of illustration and is not intended to limit embodiments of the present disclosure to the embodiments set forth herein. It will be understood by those skilled in the art that other specific modifications and changes other than those set forth in the present disclosure can be readily made to the form and details of the present disclosure without changing the technical idea or essential characteristics of the present disclosure. The scope of the present disclosure is defined by the claims attached hereto, not by the above detailed description, and the scope of the present disclosure should be interpreted to include all changes or modifications derived from the meaning and scope of the claims and their equivalents.

Claims

1. A method performed by a user equipment (UE) in a wireless communication system, the method comprising: Send to the base station capability information about the maximum number of Physical Downlink Shared Channels (PDSCH) that the UE can receive in a time slot; The configuration information received from the base station includes first information and second information. The first information includes at least one slot offset value between each of the at least one PDSCH receive slots and the transmit slot of the Hybrid Automatic Repeat Request Acknowledgment (HARQ-ACK) codebook. The second information relates to the maximum number of PDSCHs scheduled in a slot. At least one PDSCH receive time slot is determined based on the first information; Based on the second information, a HARQ-ACK codebook is generated, the HARQ-ACK codebook including as many HARQ-ACK messages as the maximum number of PDSCHs that can be scheduled in each of the determined at least one PDSCH receive slots, the HARQ-ACK messages being configured for each of the determined at least one PDSCH receive slots. as well as The generated HARQ-ACK codebook is sent to the base station.

2. The method according to claim 1, wherein, The PDSCH scheduled in the PDSCH receive slot corresponding to the HARQ-ACK information includes the PDSCH scheduled by downlink control information (DCI). Wherein, the allocation order of each of the PDSCHs scheduled in the PDSCH receive slot corresponding to the HARQ-ACK information, and The location of the HARQ-ACK information in the HARQ-ACK codebook is determined according to the order in the PDSCH reception slots.

3. The method according to claim 2, wherein, In the case where the DCI includes a field indicating the order of the PDSCHs scheduled by the DCI in the PDSCH receive slot, the order of the PDSCHs scheduled by the DCI in the PDSCH receive slot is assigned by the field, and Wherein, if the DCI does not include a field indicating the order of the PDSCH scheduled by the DCI in the PDSCH receive slot, the order of the PDSCH timings scheduled by the DCI in the PDSCH receive slot is configured as first.

4. The method according to claim 1, wherein, In cases where the UE is capable of receiving different maximum numbers of PDSCHs in a single time slot, the maximum number of PDSCHs that the UE is capable of receiving in a single time slot, as included in the capability information, is determined to be one of the different maximum numbers based on the number of Physical Resource Blocks (PRBs) allocated to the PDSCHs.

5. The method according to claim 1, further comprising: The base station receives information based on the second information regarding the maximum number of PDSCH timings configured to change within a time slot. The information used to change the maximum quantity is configured based on DCI, Media Access Control (MAC)-Control Element (CE), or Radio Resource Control (RRC).

6. A method performed by a base station in a wireless communication system, the method comprising: Receive capability information from the user equipment (UE) regarding the maximum number of physical downlink shared channels (PDSCH) that the UE can receive in a time slot; The configuration information is sent to the UE, the configuration information including first information and second information, the first information including at least one slot offset value between each PDSCH receive slot and the transmission slot of the Hybrid Automatic Repeat Request Acknowledgment (HARQ-ACK) codebook, and the second information regarding the maximum number of PDSCH opportunities scheduled in a slot; as well as Based on the second information, a HARQ-ACK codebook is received from the UE. The HARQ-ACK codebook includes as many HARQ-ACK messages as the maximum number of schedulable PDSCHs in each of at least one PDSCH receive slot determined based on the first information, and... The HARQ-ACK information is configured for each of at least one determined PDSCH receive slot.

7. The method according to claim 6, wherein, The PDSCH scheduled in the PDSCH receive slot corresponding to the HARQ-ACK information includes the PDSCH scheduled by downlink control information (DCI). Wherein, the allocation order of each of the PDSCHs scheduled in the PDSCH receive slot corresponding to the HARQ-ACK information, and The location of the HARQ-ACK information in the HARQ-ACK codebook is determined according to the order in the PDSCH reception slots.

8. The method according to claim 7, wherein, In the case where the DCI includes a field indicating the order of the PDSCHs scheduled by the DCI in the PDSCH receive slot, the order of the PDSCHs scheduled by the DCI in the PDSCH receive slot is assigned by the field, and Wherein, if the DCI does not include a field indicating the order of the PDSCH scheduled by the DCI in the PDSCH receive slot, the order of the PDSCH timings scheduled by the DCI in the PDSCH receive slot is configured as first.

9. The method according to claim 6, wherein, In cases where the UE is capable of receiving different maximum numbers of PDSCHs in a single time slot, the maximum number of PDSCHs that the UE is capable of receiving in a single time slot, as included in the capability information, is determined to be one of the different maximum numbers based on the number of Physical Resource Blocks (PRBs) allocated to the PDSCHs.

10. The method of claim 6, further comprising: Send to the UE information configured based on the second information to change the maximum number of PDSCH timings scheduled in a time slot. The information used to change the maximum quantity is configured based on DCI, Media Access Control (MAC)-Control Element (CE), or Radio Resource Control (RRC).

11. A user equipment (UE) in a wireless communication system, the UE comprising: transceiver; and The controller is connected to the transceiver. The controller is configured as follows: Send to the base station capability information about the maximum number of Physical Downlink Shared Channels (PDSCH) that the UE can receive in a time slot; The configuration information received from the base station includes first information and second information. The first information includes at least one slot offset value between each of the at least one PDSCH receive slots and the transmit slot of the Hybrid Automatic Repeat Request Acknowledgment (HARQ-ACK) codebook. The second information relates to the maximum number of PDSCHs scheduled in a slot. At least one PDSCH receive time slot is determined based on the first information; A HARQ-ACK codebook is generated based on the second information. The HARQ-ACK codebook includes as many HARQ-ACK messages as there are schedulable PDSCHs in each of the at least one determined PDSCH receive slots, and the HARQ-ACK messages are configured for each of the at least one determined PDSCH receive slots; and The generated HARQ-ACK codebook is sent to the base station.

12. The UE according to claim 11, wherein, The PDSCH scheduled in the PDSCH receive slot corresponding to the HARQ-ACK information includes the PDSCH scheduled by downlink control information (DCI). Wherein, the allocation order of each of the PDSCHs scheduled in the PDSCH receive slot corresponding to the HARQ-ACK information, and The location of the HARQ-ACK information in the HARQ-ACK codebook is determined according to the order in the PDSCH reception slots.

13. The UE according to claim 12, wherein, In the case where the DCI includes a field indicating the order of the PDSCHs scheduled by the DCI in the PDSCH receive slot, the order of the PDSCHs scheduled by the DCI in the PDSCH receive slot is assigned by the field, and Wherein, if the DCI does not include a field indicating the order of the PDSCH scheduled by the DCI in the PDSCH receive slot, the order of the PDSCH timings scheduled by the DCI in the PDSCH receive slot is configured as first.

14. The UE according to claim 11, wherein, In cases where the UE is capable of receiving different maximum numbers of PDSCHs in a single time slot, the maximum number of PDSCHs that the UE is capable of receiving in a single time slot, as included in the capability information, is determined to be one of the different maximum numbers based on the number of Physical Resource Blocks (PRBs) allocated to the PDSCHs.

15. A base station in a wireless communication system, the base station comprising: transceiver; and The controller is connected to the transceiver. The controller is configured as follows: Receive capability information from the user equipment (UE) regarding the maximum number of physical downlink shared channels (PDSCH) that the UE can receive in a time slot; Configuration information is sent to the UE, the configuration information including first information and second information, the first information including at least one slot offset value between each of at least one PDSCH receive slot and the transmit slot of the Hybrid Automatic Repeat Request Acknowledgment (HARQ-ACK) codebook, and the second information relating to the maximum number of PDSCH opportunities scheduled in a slot; and Based on the second information, a HARQ-ACK codebook is received from the UE. The HARQ-ACK codebook includes as many HARQ-ACK messages as the maximum number of schedulable PDSCHs in each of at least one PDSCH receive slot determined based on the first information, and... The HARQ-ACK information is configured for each of at least one determined PDSCH receive slot.

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