Method for transmitting feedback information for low-quality data reception in wireless communication system, and device using same

Abstract

Provided are an operation method for a device in a wireless communication system, and a device using same. According to the method, a terminal receives downlink control information from a base station, receives data scheduled by the downlink control information from the base station, and transmits hybrid automatic repeat request-acknowledgement (HARQ-ACK) information for the data to the base station. In this process, when transmitting the HARQ-ACK information, the terminal transmits, to the base station, feedback information related to a redundancy version (RV) index of retransmission data requiring retransmission from among a plurality of RV indices.

Description

Method for transmitting feedback information regarding the reception of low-quality data in a wireless communication system and device using said method

[0001] The present disclosure relates to a method for transmitting feedback information regarding the reception of low-quality data in a wireless communication system and an apparatus utilizing said method.

[0002] As more communication devices require larger communication capacities, the need for enhanced mobile broadband communication compared to existing radio access technology (RAT) is emerging. Furthermore, Massive Machine Type Communications (MTC), which connects multiple devices and objects to provide various services anytime and anywhere, is also one of the major issues to be considered in next-generation communication. In addition, communication system designs that take into account services and terminals sensitive to reliability and latency are being discussed. Thus, the introduction of next-generation radio access technologies that consider enhanced mobile broadband communication, massive MTC, and Ultra-Reliable and Low Latency Communication (URLC) is being discussed, and for convenience, this technology is referred to as new RAT or NR in this disclosure.

[0003] Meanwhile, the RV (redundancy version) index can be described as an indicator that determines which encoded bits to select and transmit when performing rate matching on transmitted data (e.g., transport block).

[0004] For example, in NR, four RV indices, such as RV0, RV1, RV2, and RV3, may be used. In the initial transmission, the transmitter typically uses RV index 0 (RV0) to transmit data. RV0 may contain the most advantageous set of bits for independently decoding the transmission block.

[0005] The receiver receives the above data, checks for errors using, for example, a Cyclic Redundancy Check (CRC), and if no errors are found, sends an Acknowledgement (ACK) to the transmitter. Then, the transmitter resets the corresponding Hybrid Automatic Repeat Request (HARQ) process and clears the buffer. When this process transmits new data the next time, it uses RV0 again.

[0006] Conversely, if the receiver fails the CRC check, it sends a NACK (negative acknowledgment) to the transmitter; in this case, the transmitter performs a retransmission using the same HARQ process ID. At this time, the transmitter sends bits different from the previous transmission, allowing the receiver to soft-combine the previously stored error data with the currently received retransmission data, thereby enhancing error correction capabilities.

[0007] In this process, the transmitter can transmit data in the order of, for example, RV0, RV2, RV3, RV1, or in the order of RV0, RV2, RV1, RV3.

[0008] However, in some cases, when a terminal receives a transmission block from a base station, it may receive the initial transmission (or the transmission for RV0) in a very poor channel environment. In this case, the terminal may fail to receive the transmission (the transmission associated with RV0) and may feed back a NACK.

[0009] In such cases, according to the prior art, the terminal may attempt to decode by receiving a retransmission having a different RV index (e.g., RV2) for the corresponding transmission block and combining it with the initial transmission via HARQ.

[0010] However, if the information received in the initial transmission is difficult to use meaningfully for decoding due to the poor channel environment, the information from the initial transmission may not be helpful for decoding. Additionally, if the information in the initial transmission is of such low quality that it is difficult to use for decoding, it may be difficult to successfully decode it through HARQ combination even if a retransmission associated with a different RV index is received.

[0011] The technical problem that the present disclosure aims to solve is to provide a method for transmitting feedback information regarding the reception of low-quality data in a wireless communication system and an apparatus utilizing said method.

[0012] A method for transmitting feedback information regarding the reception of low-quality data in a wireless communication system is provided. According to the method, a terminal receives downlink control information from a base station, receives data scheduled by the downlink control information from the base station, and transmits HARQ-ACK (hybrid automatic repeat request-acknowledgement) information regarding the data to the base station. At this time, when transmitting the HARQ-ACK information, the terminal transmits feedback information to the base station related to the RV index of the retransmitted data requiring retransmission among a plurality of RV (redundancy version) indices.

[0013] In another aspect, a terminal that executes the above method, a chipset of the terminal, and a computer-readable medium are provided.

[0014] In another aspect, a method of operation of a base station and a base station utilizing such method are provided. According to the method, the base station transmits downlink control information to a terminal, transmits data scheduled by the downlink control information to the terminal, and receives HARQ-ACK (hybrid automatic repeat request-acknowledgement) information regarding the data from the terminal, wherein the base station, upon receiving the HARQ-ACK information from the terminal, receives feedback information related to the RV index of the retransmitted data requiring retransmission among a plurality of RV (redundancy version) indices.

[0015] According to the method of the present disclosure, by having a terminal provide feedback information related to the RV index of retransmission data requiring retransmission to a base station, systomic bits essential for successful decoding can be received during retransmission. Thus, data transmission and reception performance is improved.

[0016] In addition, it can prevent delays that may occur due to the repeated retransmission of data that does not aid in decoding.

[0017] Figure 1 illustrates the system structure of a New Generation Radio Access Network (NG-RAN) to which NR is applied.

[0018] Figure 2 is a block diagram showing the radio protocol architecture for the user plane.

[0019] Figure 3 is a block diagram showing the wireless protocol structure for the control plane.

[0020] Figure 4 illustrates the functional partitioning between NG-RAN and 5GC.

[0021] Figure 5 illustrates a frame structure that can be applied in NR.

[0022] Figure 6 shows an example of a resource grid in NR.

[0023] Figure 7 shows an example of a physical resource block in NR.

[0024] Figure 8 illustrates the slot structure of an NR frame.

[0025] Figure 9 illustrates a core set.

[0026] Figure 10 illustrates an example of a slot structure for a new wireless access technology.

[0027] Figure 11 illustrates the structure of a self-contained slot.

[0028] FIG. 12 illustrates physical channels and general signal transmission.

[0029] Figure 13 illustrates the structure of the basic graph of NR.

[0030] Figure 14 illustrates the output of an interleaver in the case of 16QAM modulation.

[0031] FIG. 15 illustrates an exemplary flexible network topology to which the embodiments of the present specification can be applied.

[0032] Figure 16 illustrates the transmitted coded bits according to the RV when using a 1 / 3 code rate.

[0033] Figure 17 illustrates the case where the receiver receives the first transmission and the second transmission of the transmitter.

[0034] FIG. 18 illustrates a method of operation of a terminal according to the present disclosure.

[0035] FIG. 19 illustrates the signaling process and operation between a base station and a terminal.

[0036] FIG. 20 illustrates a wireless device that can be applied to the present specification.

[0037] Figure 21 illustrates another example of a wireless device.

[0038] Figure 22 illustrates an example of a signal processing module structure.

[0039] Figure 23 illustrates another example of a signal processing module structure within a transmission device.

[0040] FIG. 24 illustrates an example of a wireless communication device according to an embodiment of the present disclosure.

[0041] FIG. 25 illustrates a communication system (1) applicable to the present specification.

[0042] In this specification, "A or B" may mean "only A," "only B," or "both A and B." Alternatively, in this specification, "A or B" may be interpreted as "A and / or B." For example, in this specification, "A, B or C" may mean "only A," "only B," "only C," or "any combination of A, B and C."

[0043] A slash ( / ) or a comma used in this specification may mean "and / or." For example, "A / B" may mean "A and / or B." Accordingly, "A / B" may mean "only A," "only B," or "both A and B." For example, "A, B, C" may mean "A, B or C."

[0044] In this specification, "at least one of A and B" may mean "only A," "only B," or "both A and B." Additionally, in this specification, the expressions "at least one of A or B" or "at least one of A and / or B" may be interpreted as synonymous with "at least one of A and B."

[0045] Additionally, in this specification, "at least one of A, B and C" may mean "only A," "only B," "only C," or "any combination of A, B and C." Also, "at least one of A, B or C" or "at least one of A, B and / or C" may mean "at least one of A, B and C."

[0046] Additionally, parentheses used in this specification may mean "for example." Specifically, when indicated as "control information (ABC)," "ABC" may be described as an example of "control information." For example, "control information" may include DEF as another example. In other words, "control information" in this specification is not limited to "ABC," and "ABC" may be described as an example of "control information." Also, when indicated as "control information (i.e., ABC)," "ABC" may be described as an example of "control information."

[0047] In addition, terms such as "first," "second," etc. in this specification are used solely for the purpose of distinguishing one component from another and are not used to limit the components, nor are they used to limit the order or importance of the components unless specifically limited. Accordingly, a first component in one embodiment of this specification may be referred to as a second component in another embodiment, and likewise, a second component in one embodiment may be referred to as a first component in another embodiment.

[0048] In the following explanation, 'when, if, in case of' can be replaced with 'based on'.

[0049] Technical features described individually within a single drawing in this specification may be implemented individually or simultaneously. The following drawings are prepared to illustrate specific examples of this specification. The names of specific devices or specific signals / messages / fields described in the drawings are presented as examples, and therefore, the technical features of this specification are not limited to the specific names used in the following drawings.

[0050] In this specification, a terminal is a user-side device (user equipment, UE) or a consumer-side device, and may also be referred to as a first node that receives / transmits signals from / to a base station / second node / IAB node / TRP (Transmission-Reception Point). A terminal may correspond to a physical node or a logical node. A terminal may correspond to a user-side endpoint or an intermediate point between other endpoints. In communication between two points not limited to endpoints (including one-to-one / many-to-one / one-to-many / many-to-many communication), a terminal may correspond to a served node. A terminal may be a fixed-location node or a non-fixed-location (or mobile) node.

[0051] In this specification, a base station (BS) is a device on the network side and may be referred to as a second node / IAB node / x-nodeB (x-NodeB, where x may be an abbreviation related to Radio Access Technology (RAT)) / TRP. A base station may correspond to a physical node or a logical node. A base station may correspond to an endpoint on the network side or an intermediate point between other endpoints. In communication between two points not limited to endpoints (including one-to-one / many-to-one / one-to-many / many-to-many communication), a base station may correspond to a serving node. A base station may be a node with a fixed location or a node without a fixed location.

[0052] In this specification, higher layer parameters may be set for the terminal, pre-set, or pre-defined. For example, a base station may transmit higher layer parameters to the terminal. For example, the terminal may transmit parameters such as capability to the base station as higher layer parameters. For example, higher layer parameters may be transmitted via RRC (radio resource control) signaling or MAC (medium access control) signaling.

[0053] In this specification, information / state / parameters being "configured" or "pre-configured" may be interpreted as the information / state / parameters being provided / pre-provided to the terminal through pre-defined signaling (e.g., SIB, MAC, RRC) from the base station. In this specification, information / state / parameters being "defined" or "pre-defined" may be interpreted as being known or stored in advance by the base station and the terminal without signaling between the base station and the terminal.

[0054] The technology described in this specification can be used in various wireless communication systems such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access). CDMA can be implemented with wireless technologies such as UTRA (universal terrestrial radio access) or CDMA2000. TDMA can be implemented with wireless technologies such as GSM (global system for mobile communications) / GPRS (general packet radio service) / EDGE (enhanced data rates for GSM evolution). OFDMA can be implemented with wireless technologies such as IEEE (institute of electrical and electronics engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, E-UTRA (evolved UTRA), LTE (long term evolution), and 5G NR.

[0055] The technology described in this specification can be implemented as 6G wireless technology and applied to various 6G systems. For example, 6G systems may have key factors such as eMBB (enhanced mobile broadband), URLLC (ultra-reliable low latency communications), mMTC (massive machine-type communication), AI (artificial intelligence) integrated communication, tactile internet, high throughput, high network capacity, high energy efficiency, low backhaul and access network congestion, and enhanced data security.

[0056] In the following, the downlink (DL) refers to communication from a base station to a terminal, and the uplink (UL) refers to communication from a terminal to a base station. In the downlink, the transmitter may be part of the base station, and the receiver may be part of the terminal. In the uplink, the transmitter may be part of the terminal, and the receiver may be part of the base station. The base station may be referred to as the first communication device, and the terminal as the second communication device. The term base station (BS) may be replaced by terms such as fixed station, Node B, eNB (evolved-NodeB), gNB (Next Generation NodeB), BTS (base transceiver system), Access Point (AP), network (5G network), AI (Artificial Intelligence) system / module, RSU (road side unit), robot, drone (Unmanned Aerial Vehicle, UAV), AR (Augmented Reality) device, VR (Virtual Reality) device, etc.In addition, the terminal may be fixed or mobile and may be replaced with terms such as UE (User Equipment), MS (Mobile Station), UT (user terminal), MSS (Mobile Subscriber Station), SS (Subscriber Station), AMS (Advanced Mobile Station), WT (Wireless terminal), MTC (Machine-Type Communication) device, M2M (Machine-to-Machine) device, D2D (Device-to-Device) device, vehicle, RSU (road side unit), robot, AI (Artificial Intelligence) module, drone (Unmanned Aerial Vehicle, UAV), AR (Augmented Reality) device, VR (Virtual Reality) device.

[0057] The following technologies can be used in various wireless access systems such as CDMA, FDMA, TDMA, OFDMA, SC-FDMA, etc. UTRA is part of UMTS (Universal Mobile Telecommunications System). 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) is part of E-UMTS (Evolved UMTS) using E-UTRA, and LTE-A (Advanced) / LTE-A pro is an evolved version of 3GPP LTE. 3GPP NR (New Radio or New Radio Access Technology) is an evolved version of 3GPP LTE / LTE-A / LTE-A pro.

[0058] For the sake of clarity, the description is based on 3GPP communication systems (e.g., LTE-A, NR), but the technical scope of this disclosure is not limited thereto. LTE refers to technology from 3GPP TS 36.xxx Release 8 onwards. Specifically, LTE technology from 3GPP TS 36.xxx Release 10 onwards is referred to as LTE-A, and LTE technology from 3GPP TS 36.xxx Release 13 onwards is referred to as LTE-A pro. 3GPP NR refers to technology from TS 38.xxx Release 15 onwards. LTE / NR may be referred to as a 3GPP system. "xxx" indicates a specific standard document number. LTE / NR may be collectively referred to as a 3GPP system. Regarding background technology, terms, abbreviations, etc. used in the description of this disclosure, reference may be made to matters described in standard documents published prior to this disclosure. For example, the following documents may be referenced.

[0059] 3GPP LTE

[0060] - 36.211: Physical channels and modulation

[0061] - 36.212: Multiplexing and channel coding

[0062] - 36.213: Physical layer procedures

[0063] - 36.300: Overall description

[0064] - 36.331: Radio Resource Control (RRC)

[0065] 3GPP NR

[0066] - 38.211: Physical channels and modulation

[0067] - 38.212: Multiplexing and channel coding

[0068] - 38.213: Physical layer procedures for control

[0069] - 38.214: Physical layer procedures for data

[0070] - 38.300: NR and NG-RAN Overall Description

[0071] - 36.331: Radio Resource Control (RRC) protocol specification

[0072] 이하에서, 아래의 정의 및 약어(Definition and Abbreviations)를 사용할 수 있다.

[0073] BM: beam management

[0074] CQI: channel quality indicator

[0075] CRI: CSI-RS (channel state information - reference signal) resource indicator

[0076] CSI: channel state information

[0077] CSI-IM: channel state information - interference measurement

[0078] CSI-RS: channel state information - reference signal

[0079] DMRS: demodulation reference signal

[0080] FDM: frequency division multiplexing

[0081] FFT: fast Fourier transform

[0082] IFDMA: interleaved frequency division multiple access

[0083] IFFT: inverse fast Fourier transform

[0084] L1-RSRP: Layer 1 reference signal received power

[0085] L1-RSRQ: Layer 1 reference signal received quality

[0086] MAC: medium access control

[0087] MCS: Modulation and coding scheme

[0088] NZP: non-zero power

[0089] OFDM: orthogonal frequency division multiplexing

[0090] PDCCH: physical downlink control channel

[0091] PDSCH: physical downlink shared channel

[0092] PMI: precoding matrix indicator

[0093] PUCCH: Physical uplink control channel

[0094] PUSCH: Physical uplink shared channel

[0095] RE: resource element

[0096] RI: Rank indicator

[0097] RRC: radio resource control

[0098] RSSI: received signal strength indicator

[0099] Rx: Reception

[0100] QCL: quasi co-location

[0101] SINR: signal to interference and noise ratio

[0102] SSB (or SS / PBCH block): synchronization signal block (including primary synchronization signal, secondary synchronization signal and physical broadcast channel)

[0103] TDM: time division multiplexing

[0104] TRP: transmission and reception point

[0105] TRS: tracking reference signal

[0106] Tx: transmission

[0107] UE: user equipment

[0108] ZP: zero power

[0109] As more communication devices require larger communication capacities, the need for enhanced mobile broadband communication compared to existing radio access technology is emerging. Furthermore, massive Machine Type Communications (MTC), which connects multiple devices and objects to provide various services anytime and anywhere, is also one of the major issues to be considered in next-generation communication. In addition, communication system designs that consider services and terminals sensitive to reliability and latency are being discussed. As such, the introduction of next-generation radio access technologies considering eMBB (enhanced mobile broadband communication), Mmtc (massive MTC), and URLLC (Ultra-Reliable and Low Latency Communication) is being discussed, and for convenience, this technology is referred to as NR in this specification. NR is an expression representing an example of 5G radio access technology (RAT).

[0110] A new RAT system including NR uses an OFDM transmission method or a similar transmission method. The new RAT system may follow OFDM parameters different from those of LTE. Alternatively, the new RAT system may follow the existing LTE / LTE-A numerology but have a larger system bandwidth (e.g., 100 MHz). Or, a single cell may support multiple numerologies. For example, terminals operating with different numerologies may coexist within a single cell.

[0111] Numerology corresponds to a single subcarrier spacing in the frequency domain. Different numerologies can be defined by scaling the reference subcarrier spacing to an integer N.

[0112] The three major requirement areas of 5G include (1) the Enhanced Mobile Broadband (eMBB) area, (2) the Massive Machine Type Communication (mMTC) area, and (3) the Ultra-reliable and Low Latency Communications (URLC) area.

[0113] Some use cases may require multiple domains for optimization, while others may focus on only a single Key Performance Indicator (KPI). 5G supports these diverse use cases in a flexible and reliable way.

[0114] eMBB goes far beyond basic mobile internet access, covering media and entertainment applications in rich interactive tasks, the cloud, or augmented reality. Data is one of the core drivers of 5G, and dedicated voice services may not be seen for the first time in the 5G era. In 5G, voice is expected to be processed simply as an application using the data connection provided by the communication system. The main causes for the increased traffic volume are the increase in content size and the growing number of applications requiring high data transfer rates. Streaming services (audio and video), interactive video, and mobile internet connectivity will become more widely used as more devices connect to the internet. Many of these applications require always-on connectivity to push real-time information and notifications to users. Cloud storage and applications are growing rapidly on mobile communication platforms, and this can be applied to both work and entertainment. Furthermore, cloud storage is a specific use case driving the growth of uplink data transfer rates. 5G is also used for remote work in the cloud, requiring much lower end-to-end latency to maintain an excellent user experience when haptic interfaces are used. Entertainment, for example, cloud gaming and video streaming, is another key factor increasing the demand for mobile broadband capabilities. Entertainment is essential on smartphones and tablets anywhere, including in highly mobile environments such as trains, cars, and airplanes. Other use cases include augmented reality for entertainment and information retrieval. Here, augmented reality requires very low latency and instantaneous data volumes.

[0115] In addition, one of the most anticipated use cases for 5G is the ability to seamlessly connect embedded sensors across all fields, such as mMTC. It is predicted that the number of potential IoT devices will reach 20.4 billion by 2020. Industrial IoT is one of the areas where 5G plays a key role in enabling smart cities, asset tracking, smart utilities, agriculture, and security infrastructure.

[0116] URLLC includes new services that will transform industries through ultra-reliable and available low-latency links, such as remote control of critical infrastructure and self-driving vehicles. Levels of reliability and latency are essential for smart grid control, industrial automation, robotics, and drone control and coordination.

[0117] We will examine several usage examples in more detail.

[0118] 5G can complement FTTH (fiber-to-the-home) and cable-based broadband (or DOCSIS) as a means of providing streams rated at hundreds of megabits per second to gigabits per second. These high speeds are required for virtual and augmented reality, as well as for delivering TV at resolutions of 4K and above (6K, 8K, and higher). VR (Virtual Reality) and AR ( Augmented Reality) applications include near-immersive sports matches. Certain applications may require special network configurations. For example, in the case of VR games, game companies may need to integrate core servers with the network operator's edge network servers to minimize latency.

[0119] The automotive sector is expected to become a significant new driving force for 5G, with numerous use cases for mobile communication within vehicles. For example, passenger entertainment requires high-capacity and high-mobility mobile broadband simultaneously. This is because future users will continue to expect high-quality connectivity regardless of their location or speed. Another application in the automotive sector is the augmented reality dashboard. This displays information overlaid onto what the driver is looking through the windshield, allowing them to identify objects in the dark and providing the driver with information about the objects' distances and movements. In the future, wireless modules will enable communication between vehicles, information exchange between vehicles and supporting infrastructure, and information exchange between vehicles and other connected devices (e.g., devices accompanying pedestrians). Safety systems will allow drivers to drive more safely by guiding them to alternative courses of action, thereby reducing the risk of accidents. The next step will be remotely controlled or self-driven vehicles. This requires highly reliable and very fast communication between different self-driven vehicles and between vehicles and infrastructure. In the future, self-driving vehicles will perform all driving activities, allowing drivers to focus solely on traffic anomalies that the vehicle itself cannot identify. The technical requirements for self-driving vehicles demand ultra-low latency and ultra-high reliability to increase traffic safety to a level unattainable by humans.

[0120] Smart cities and smart homes, referred to as a smart society, will be embedded with high-density wireless sensor networks. Distributed networks of intelligent sensors will identify conditions for maintaining the cost-effective and energy-efficient maintenance of the city or home. A similar setup can be implemented for each household. Temperature sensors, window and heating controllers, burglar alarms, and home appliances are all wirelessly connected. Many of these sensors typically feature low data transfer rates, low power consumption, and low cost. However, for example, real-time HD video may be required for certain types of devices for surveillance.

[0121] The consumption and distribution of energy, including heat or gas, are becoming highly decentralized, requiring automated control of distributed sensor networks. Smart grids interconnect these sensors using digital information and communication technologies to collect information and act accordingly. Since this information may include the behavior of suppliers and consumers, smart grids can improve efficiency, reliability, economic viability, production sustainability, and the automated distribution of fuels such as electricity. A smart grid can also be viewed as another sensor network with low latency.

[0122] The health sector possesses numerous applications that can benefit from mobile communications. Communication systems can support telemedicine, providing clinical care from remote locations. This helps reduce distance barriers and improves access to medical services that are not consistently available in remote rural areas. It is also used to save lives during critical medical care and emergencies. Mobile communication-based wireless sensor networks can provide remote monitoring and sensors for parameters such as heart rate and blood pressure.

[0123] Wireless and mobile communications are becoming increasingly important in industrial applications. Wiring is expensive to install and maintain. Therefore, the potential to replace cables with reconfigurable wireless links presents an attractive opportunity in many industries. However, achieving this requires wireless connections to operate with latency, reliability, and capacity comparable to cables, while also simplifying their management. Low latency and a very low probability of error are new requirements that 5G needs to meet.

[0124] Logistics and freight tracking are important use cases for mobile communications that use location-based information systems to enable the tracking of inventory and packages anywhere. Use cases for logistics and freight tracking typically require low data rates but necessitate wide coverage and reliable location information.

[0125] Multi-Input Multi-Output (MIMO) technology in NR systems provides a scalable and flexible MIMO framework. Fundamentally, this includes beam-based operation, a scalable and flexible Channel State Information (CSI) codebook, reference signal (RS) design, and codebook design for CSI Type I and CSI Type II. Additionally, improvements have been introduced to support CSI Type II codebooks for Multi-User (MU)-MIMO, multiple Transceive Points (TRP) or multiple panel transmission operations based on backhaul conditions, multi-beam operation, support for high uplink transmission power, and reference signals with low Peak-to Average Power Ratio (PAPR) characteristics. Furthermore, beam management measures to reduce beam failure for high-speed moving radio devices in high frequency ranges, expansion of multiple TRP transmission in uplink and downlink, Sounding Reference Signal (SRS) for capacity and coverage expansion, and improvements to Type II CSI-RS may be supported.

[0126] A conventional wireless communication system is described. This can also be called an E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) or LTE (Long Term Evolution) / LTE-A system.

[0127] E-UTRAN includes a base station (BS) that provides a control plane and a user plane to a terminal (User Equipment, UE). The terminal can be fixed or mobile and may be referred to by other terms such as MS (Mobile station), UT (User Terminal), SS (Subscriber Station), MT (mobile terminal), Wireless Device, or terminal. A base station refers to a fixed station that communicates with a terminal and may be referred to by other terms such as eNB (evolved-NodeB), gNB (gNodeB), BTS (Base Transceiver System), or Access Point.

[0128] Base stations can be connected to each other via the X2 interface. Base stations are connected to the EPC (Evolved Packet Core) via the S1 interface, more specifically to the MME (Mobility Management Entity) via S1-MME, and to the S-GW (Serving Gateway) via S1-U.

[0129] The EPC consists of the MME, S-GW, and P-GW (Packet Data Network Gateway). The MME holds information regarding terminal connection details and capabilities, and this information is primarily used for managing terminal mobility. The S-GW is a gateway with an E-UTRAN endpoint, and the P-GW is a gateway with a PDN endpoint.

[0130] Figure 1 illustrates the system structure of a New Generation Radio Access Network (NG-RAN) to which NR is applied.

[0131] Referring to FIG. 1, the NG-RAN may include gNBs and / or eNBs that provide user plane and control plane protocol termination to terminals. FIG. 1 illustrates a case where only gNBs are included. The gNBs (eNBs) are connected to each other via Xn interfaces. The gNBs and eNBs are connected to the 5G Core Network (5GC) via NG interfaces. More specifically, they are connected to the access and mobility management function (AMF) via NG-C interfaces and to the user plane function (UPF) via NG-U interfaces.

[0132] The layers of the Radio Interface Protocol between a terminal and a network can be classified into L1 (Layer 1), L2 (Layer 2), and L3 (Layer 3) based on the lower three layers of the Open System Interconnection (OSI) model, which is widely known in communication systems. Among these, the physical layer, which belongs to Layer 1, provides information transfer services using a physical channel, while the Radio Resource Control (RRC) layer, located at Layer 3, performs the role of controlling radio resources between the terminal and the network. To this end, the RRC layer exchanges RRC messages between the terminal and the base station.

[0133] FIG. 2 is a block diagram showing the radio protocol architecture for the user plane. FIG. 3 is a block diagram showing the radio protocol architecture for the control plane. The user plane is a protocol stack for transmitting user data, and the control plane is a protocol stack for transmitting control signals.

[0134] Referring to Figures 2 and 3, the physical layer (PHY layer) provides information transfer services to upper layers using a physical channel. The physical layer is connected to the upper layer, the MAC (Medium Access Control) layer, through a transport channel. Data travels between the MAC layer and the physical layer through the transport channel. Transport channels are classified according to how and with what characteristics data is transmitted through a wireless interface.

[0135] Data travels between different physical layers, specifically between the physical layers of the transmitter and the receiver, through a physical channel. This physical channel can be modulated using the Orthogonal Frequency Division Multiplexing (OFDM) method and utilizes time and frequency as wireless resources.

[0136] The functions of the MAC layer include mapping between logical channels and transport channels, and multiplexing / demultiplexing MAC SDUs (service data units) belonging to logical channels into transport blocks provided to physical channels over the transport channel. The MAC layer provides services to the RLC (Radio Link Control) layer through logical channels.

[0137] The functions of the RLC layer include the concatenation, segmentation, and reassembly of RLC SDUs. To ensure the various Quality of Service (QoS) required by Radio Bearers (RBs), the RLC layer provides three operating modes: Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). AM RLC provides error correction through Automatic Repeat Requests (ARQ).

[0138] The RRC (Radio Resource Control) layer is defined only in the control plane. The RRC layer is responsible for controlling logical channels, transmission channels, and physical channels in relation to the configuration, reconfiguration, and release of wireless bearers. RB refers to a logical path provided by the first layer (PHY layer) and the second layer (MAC layer, RLC layer, PDCP layer) for data transmission between a terminal and a network.

[0139] The functions of the PDCP (Packet Data Convergence Protocol) layer in the user plane include the delivery of user data, header compression, and ciphering. The functions of the PDCP (Packet Data Convergence Protocol) layer in the control plane include the delivery of control plane data and encryption / integrity protection.

[0140] The establishment of an RB refers to the process of defining the characteristics of the wireless protocol layer and channel to provide specific services, and setting their respective specific parameters and operating methods. RBs can be further divided into two types: SRBs (Signaling RBs) and DRBs (Data RBs). SRBs are used as a channel for transmitting RRC messages in the control plane, while DRBs are used as a channel for transmitting user data in the user plane.

[0141] When an RRC connection is established between the terminal's RRC layer and the E-UTRAN's RRC layer, the terminal is in an RRC connected state; otherwise, it is in an RRC idle state.

[0142] Downlink transmission channels for transmitting data from a network to a terminal include a Broadcast Channel (BCH) for transmitting system information and a Shared Channel (SCH) for transmitting user traffic or control messages. Traffic or control messages for downlink multicast or broadcast services may be transmitted via the Shared Channel (SCH) or via a separate Multicast Channel (MCH). Meanwhile, uplink transmission channels for transmitting data from a terminal to a network include a Random Access Channel (RACH) for transmitting initial control messages and a Shared Channel (SCH) for transmitting user traffic or control messages.

[0143] Logical channels that are above the transmission channel and map to the transmission channel include BCCH (Broadcast Control Channel), PCCH (Paging Control Channel), CCCH (Common Control Channel), MCCH (Multicast Control Channel), and MTCH (Multicast Traffic Channel).

[0144] A physical channel consists of multiple OFDM symbols in the time domain and multiple subcarriers in the frequency domain. A single subframe consists of multiple OFDM symbols in the time domain. A resource block is a resource allocation unit composed of multiple OFDM symbols and multiple subcarriers. Additionally, each subframe may utilize specific subcarriers of specific OFDM symbols (e.g., the first OFDM symbol) within that subframe for a Physical Downlink Control Channel (PDCCH), e.g., an L1 / L2 control channel. The Transmission Time Interval (TTI) is the unit time for subframe transmission.

[0145] Figure 4 illustrates the functional partitioning between NG-RAN and 5GC.

[0146] Referring to FIG. 4, the gNB can provide functions such as Inter Cell Radio Resource Management (Inter Cell RRM), Radio Bearer Management (RB control), Connection Mobility Control, Radio Admission Control, Measurement Configuration & Provision, and Dynamic Resource Allocation. The AMF can provide functions such as NAS security and idle state mobility processing. The UPF can provide functions such as Mobility Anchoring and PDU processing. The SMF (Session Management Function) can provide functions such as terminal IP address allocation and PDU session control.

[0147] Figure 5 illustrates a frame structure that can be applied in NR.

[0148] Referring to FIG. 5, radio frames (hereinafter abbreviated as frames) may be used for uplink and downlink transmission in NR. A frame has a length of 10 ms and can be defined as two 5 ms half-frames (HF). A half-frame can be defined as five 1 ms subframes (SF). A frame may contain 10 subframes. A subframe may be divided into one or more slots, and the number of slots within a subframe depends on the Subcarrier Spacing (SCS). Each slot contains 12 or 14 OFDM(A) symbols depending on the Cyclic Prefix (CP). When a normal CP is used, each slot contains 14 symbols. When an extended CP is used, each slot contains 12 symbols. Here, the symbol may include OFDM symbols (or CP-OFDM symbols) or SC-FDMA symbols (or DFT-s-OFDM symbols). The mini-slot may include, for example, 2, 4, or 7 symbols, or more or fewer symbols.

[0149] An NR system can support multiple numerologies. Here, the numerology can be defined by subcarrier spacing and cyclic prefix (CP) overhead. In this case, multiple subcarrier spacings can be derived by scaling the basic subcarrier spacing by an integer N. Furthermore, even if it is assumed that very low subcarrier spacings are not used at very high carrier frequencies, the numerology used can be selected independently of the frequency band. Additionally, various frame structures corresponding to multiple numerologies can be supported in an NR system.

[0150] Below, we examine the Orthogonal Frequency Division Multiplexing (OFDM) numerologies and frame structures that can be considered in NR systems. Refer to Table 1 for the various OFDM numerologies supported in NR systems.

[0151] Table 1 below shows an example of a subcarrier spacing configuration (also referred to as subcarrier spacing configuration) μ.

[0152] [Table 1]

[0153]

[0154] Regarding the frame structure in an NR system, the magnitude of various fields in the time domain is T s =1 / (Δf max· N f It can be expressed as a multiple of the time unit of ). Here, Δf max =480·10 3 and N f = 409. Downlink and uplink transmission is T f =(Δf max ·N f / 100)·T s It consists of radio frames having an interval of =10ms. Here, each radio frame is T sf =(Δf max ·N f / 1000)·T s It consists of 10 subframes with an interval of = 1ms. In this case, there may be one set of frames for the uplink and one set of frames for the downlink. Additionally, the transmission of uplink frame number i from the terminal (User Equipment, UE) occurs T before the start of the corresponding downlink frame at the terminal. TA =N TA ·T sMust start previously. For numerology μ, slots are n within a subframe. μ s ∈{0, ..., N slots,μ subframe Numbered in increasing order of {-1}, and n within the wireless frame μ s,f ∈{0, ..., N slots,μ frame Numbered in increasing order of {-1}. One slot is N μ symb It consists of consecutive OFDM symbols of, and N μ symb is determined by the numerology and slot configuration used. Slot n in a subframe μ s The start is OFDM symbol n in the same subframe. μ s N μ symb It is aligned with the start and time of. Not all terminals can transmit and receive simultaneously, which means that not all OFDM symbols in the downlink slot or uplink slot can be used.

[0155] The following Table 2 shows the number of slots (N) within a frame according to the subcarrier spacing setting μ. frame,μ slot ), number of slots in the subframe (N subframe,μ slot ), number of symbols in the slot (N slot symb Examples include ) etc.

[0156] [Table 2]

[0157]

[0158] Table 3 below illustrates how the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary depending on the SCS when an extended CP is used.

[0159] [Table 3]

[0160]

[0161] In an NR system, OFDM(A) numerology (e.g., SCS, CP length, etc.) can be configured differently among multiple cells merged into a single terminal. Accordingly, the (absolute time) interval of a time resource (e.g., SF, slot, or TTI) (collectively referred to as TU (Time Unit) for convenience) composed of the same number of symbols can be configured differently among the merged cells.

[0162] Regarding physical resources in an NR system, antenna ports, resource grids, resource elements, resource blocks, and carrier parts may be considered. Below, we will examine in detail the aforementioned physical resources that can be considered in an NR system. First, regarding antenna ports, an antenna port is defined such that the channel carrying a symbol on the antenna port can be inferred from the channel carrying another symbol on the same antenna port. If the large-scale property of the channel carrying a symbol on one antenna port can be inferred from the channel carrying a symbol on another antenna port, the two antenna ports can be said to be in a QC / QCL (quasi-co-located or quasi-co-location) relationship. Here, the large-scale property includes one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.

[0163] Figure 6 shows an example of a resource grid in NR.

[0164] Referring to Fig. 6, the resource grid is N in the frequency domain. μ RB N RB sc It consists of subcarriers, and one subframe is 14·2 μ It is described by way of example as being composed of OFDM symbols, but is not limited thereto. In an NR system, the transmitted signal is N μ RB N RB sc One or more resource grids composed of subcarriers and 2 μ N (μ) symb It is described by the OFDM symbols of. Here, N μ RB≤ N max,μ RB It is. The above N max,μ RB represents the maximum transmission bandwidth, which may vary between numerologies as well as between uplink and downlink. In this case, a single resource grid may be established for each numerology μ and antenna port p. Each element of the resource grid for numerology μ and antenna port p is referred to as a resource element and is uniquely identified by an index pair {index in the frequency domain, position of the symbol within a subframe}. Indices p and μ may be dropped if there is no risk of confusion or if a specific antenna port or numerology is not specified. Additionally, a resource block (RB) is N in the frequency domain RB sc =12 is defined as consecutive subcarriers.

[0165] Point A serves as a common reference point for the resource block grid and is acquired as follows.

[0166] offsetToPointA for the primary cell (Pcell) downlink represents the frequency offset between Point A and the lowest subcarrier of the lowest resource block that overlaps with the SS / PBCH block used by the terminal for initial cell selection, expressed in resource block units assuming a 15 kHz subcarrier spacing for FR1 and a 60 kHz subcarrier spacing for FR2, and absoluteFrequencyPointA represents the frequency-position of Point A as expressed in the ARFCN (absolute radio-frequency channel number).

[0167] Common resource blocks are numbered upwards from 0 in the frequency domain for a subcarrier spacing setting μ. The center of subcarrier 0 of common resource block 0 for a subcarrier spacing setting μ coincides with 'Point A'. Common resource block number n in the frequency domain μ CRB The resource element (k,l) for the subcarrier spacing setting μ is given as shown in the equation below.

[0168] [Equation 1]

[0169]

[0170] k is defined relative to point A such that k=0 corresponds to a subcarrier centered at point A. Physical resource blocks range from 0 to N within the bandwidth part (BWP). size BWP,i Numbers are assigned up to -1, and i is the BWP number. Physical resource block n in BWP i. PRB and common resource block n CRBThe relationship between them is given by the following equation.

[0171] [Equation 2]

[0172]

[0173] N start BWP,i is a common resource block where BWP starts relative to common resource block 0.

[0174] Figure 7 shows an example of a physical resource block in NR.

[0175] Referring to FIG. 7, the physical resource block (PRB) can be composed of different frequency resources and time resources depending on the subcarrier spacing.

[0176] Figure 8 illustrates the slot structure of an NR frame.

[0177] Referring to FIG. 8, a slot may contain multiple symbols in the time domain. For example, in the case of a normal CP, one slot may contain 14 symbols, but in the case of an extended CP, one slot may contain 12 symbols. A carrier may contain multiple subcarriers in the frequency domain. A Resource Block (RB) may be defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A Bandwidth Part (BWP) may be defined as multiple consecutive (P)RBs in the frequency domain and may correspond to a single numerology (e.g., SCS, CP length, etc.). A carrier may contain up to N (e.g., 4 or 5) BWPs. Data communication is performed through the activated BWP, and only one BWP may be activated for a single terminal. In a resource grid, each element is referred to as a resource element (RE), and a single complex symbol can be mapped to it.

[0178] As another example, in the time domain, a standard CP typically contains 7 symbols per slot, whereas an extended CP contains 6 symbols per slot. The carrier contains multiple subcarriers in the frequency domain. A Resource Block (RB) is defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A Bandwidth Part (BWP) is defined as multiple consecutive (P)RBs in the frequency domain and can correspond to a single numerology (e.g., SCS, CP length, etc.). The carrier can contain up to N (e.g., 5) BWPs. Data communication is performed through the active BWPs, and only one BWP can be active for a single terminal. In the resource grid, each element is referred to as a Resource Element (RE) and can be mapped to a single complex symbol.

[0179] The PDCCH (physical downlink control channel) can be composed of one or more CCEs (control channel elements) as shown in Table 4 below.

[0180] [Table 4]

[0181]

[0182] For example, a PDCCH can be transmitted through a resource consisting of 1, 2, 4, 8, or 16 CCEs. Here, a CCE consists of 6 REGs (resource element groups), and one REG consists of one resource block in the frequency domain and one OFDM (orthogonal frequency division multiplexing) symbol in the time domain.

[0183] Monitoring means decoding each PDCCH candidate according to the DCI (downlink control information) format. The terminal monitors a set of PDCCH candidates in one or more core sets (CORESET, described below) on the active DL BWP of each active serving cell where PDCCH monitoring is configured, according to the corresponding set of search spaces.

[0184] In NR, a new unit called a control resource set (CORESET) can be introduced. A terminal can receive PDCCH from the core set.

[0185] Figure 9 illustrates a core set.

[0186] Referring to Fig. 9, the core set is N in the frequency domain. CORESET RB It consists of N resource blocks, and in the time domain N CORESET symb ∈ Can be composed of {1, 2, 3} symbols. N CORESET RB , N CORESET symb This can be provided by the base station through an upper layer signal. As illustrated in FIG. 9, the core set may include a plurality of CCEs (or REGs).

[0187] The terminal can attempt to detect PDCCH in units of 1, 2, 4, 8, or 16 CCEs within a core set. One or more CCEs that can attempt to detect PDCCH may be called PDCCH candidates. The terminal may be configured with multiple core sets.

[0188] In conventional wireless communication systems (e.g., LTE / LTE-A), the control domain was configured across the entire system band used by the base station. With the exception of some terminals that support only a narrow band (e.g., eMTC / NB-IoT terminals), all terminals had to be able to receive wireless signals across the entire system band of the base station in order to properly receive and decode control information transmitted by the base station.

[0189] On the other hand, NR introduced the aforementioned core set. A core set can be described as a radio resource for control information that a terminal must receive, and in the frequency domain, only a portion of the system band can be used instead of the entire system band. Additionally, in the time domain, only a portion of the symbols within a slot can be used. A base station can allocate a core set to each terminal and transmit control information through the allocated core set. In NR, a terminal can receive control information from a base station even without necessarily receiving the entire system band.

[0190] A core set may include a terminal-specific core set for transmitting terminal-specific control information and a common core set for transmitting control information common to all terminals.

[0191] Meanwhile, in NR, high reliability may be required depending on the application field, and in such situations, the target block error rate (BLER) for downlink control information (DCI) transmitted through a downlink control channel (e.g., physical downlink control channel: PDCCH) can be significantly lower than that of conventional technology. As an example of a method to satisfy such requirements for high reliability, the amount of content included in the DCI can be reduced, and / or the amount of resources used during DCI transmission can be increased. In this case, the resources may include at least one of resources in the time domain, resources in the frequency domain, resources in the code domain, and resources in the space domain.

[0192] The following technologies / features can be applied in NR.

[0193] Self-contained subframe structure

[0194] Figure 10 illustrates an example of a slot structure for a new wireless access technology.

[0195] In NR, for the purpose of minimizing latency, a structure in which the control channel and the data channel are time-division multiplexed (TDM) within a single TTI, as shown in Fig. 10, can be considered.

[0196] Figure 10 illustrates an example in which a downlink control area is located at the front of the TTI and an uplink control area is located at the back of the TTI. The area between the downlink control area and the uplink control area may be used for transmitting downlink data (DL data) or for transmitting uplink data (UL data). A characteristic of this structure is that downlink (DL) reception and uplink (UL) transmission proceed sequentially within a single subframe / slot, allowing DL data to be received and UL ACK / NACK (Acknowledgement / Not-acknowledgement) to be transmitted within a single subframe / slot. Consequently, the time required for data retransmission in the event of a data transmission error is reduced, thereby minimizing the latency of the final data delivery.

[0197] As such, in a structure where the data and control domains are TDMed, a time gap is required for the transition process between the base station and the terminal from transmit mode to receive mode or from receive mode to transmit mode. To this end, in a self-contained subframe structure, some OFDM symbols at the time of transition from DL to UL can be set as a guard period (GP).

[0198] Figure 11 illustrates the structure of a self-contained slot.

[0199] In an NR system, a single slot may contain a DL control channel, DL or UL data, a UL control channel, etc. For example, the first N symbols within the slot may be used to transmit a DL control channel (hereinafter referred to as the DL control area), and the last M symbols within the slot may be used to transmit a UL control channel (hereinafter referred to as the UL control area). N and M are each integers greater than or equal to 0. The resource area (hereinafter referred to as the data area) located between the DL control area and the UL control area may be used for transmitting DL data or for transmitting UL data. As an example, the following configuration may be considered. Each section is listed in chronological order.

[0200] 1. DL only configuration

[0201] 2. UL only configuration

[0202] 3. Mixed UL-DL Configuration

[0203] - DL Area + GP (Guard Period) + UL Control Area

[0204] - DL Control Area + GP + UL Area

[0205] DL Area: (i) DL Data Area, (ii) DL Control Area + DL Data Area

[0206] UL Area: (i) UL Data Area, (ii) UL Data Area + UL Control Area

[0207] In the DL control area, PDCCH can be transmitted, and in the DL data area, PDSCH (physical downlink shared channel) can be transmitted. In the UL control area, PUCCH (physical uplink control channel) can be transmitted, and in the UL data area, PUSCH (physical uplink shared channel) can be transmitted. In PDCCH, DCI (Downlink Control Information), such as DL data scheduling information and UL data scheduling information, can be transmitted. In PUCCH, UCI (Uplink Control Information), such as ACK / NACK (Positive Acknowledgement / Negative Acknowledgement) information for DL ​​data, CSI (Channel State Information) information, and SR (Scheduling Request), can be transmitted. GP provides a time gap during the process of the base station and the terminal switching from transmit mode to receive mode or from receive mode to transmit mode. Within a subframe, some symbols at the point of transition from DL to UL can be set as GP.

[0208] System information of the NR system can be transmitted via broadcasting. In this case, analog beams belonging to different antenna panels within a single symbol can be transmitted simultaneously, and a method is being discussed to introduce a Beam Reference Signal (BRS), which is a reference signal (RS) transmitted by applying a single analog beam (corresponding to a specific antenna panel) to measure the channel for each analog beam. The BRS can be defined for multiple antenna ports, and each antenna port of the BRS can correspond to a single analog beam. In this case, unlike the BRS, the synchronization signal or xPBCH can be transmitted by applying all analog beams within an analog beam group so that any terminal can receive it well.

[0209] In NR, the synchronization signal block (SSB, or may also be referred to as the synchronization signal and physical broadcast channel: SS / PBCH) in the time domain may consist of four OFDM symbols numbered in ascending order from 0 to 3 within the synchronization signal block, and the PBCH associated with the primary synchronization signal (PSS), secondary synchronization signal (SSS), and demodulation reference signal (DMRS) may be mapped to the symbols. As previously mentioned, the synchronization signal block may also be referred to as the SS / PBCH block.

[0210] In NR, multiple synchronization signal blocks can be transmitted at different times, and since an SSB can be used to perform initial access (IA), serving cell measurement, etc., it is desirable for the SSB to be transmitted first when transmission times and resources overlap with other signals. To this end, the network can broadcast the transmission time and resource information of the SSB or indicate it through UE-specific RRC signaling.

[0211] In NR, beam-based transmission and reception operations can be performed. If the reception performance of the current serving beam deteriorates, a process to find a new beam can be performed through a process called beam failure recovery (BFR).

[0212] Since BFR is not a process that declares an error or failure regarding the link between the network and the terminal, it can be assumed that the connection with the current serving cell is maintained even when the BFR process is performed. During the BFR process, measurements are taken on different beams configured by the network (beams can be expressed as CSI-RS ports or SSB (synchronization signal block) indices, etc.), and the best beam for the terminal can be selected. The terminal can proceed with the BFR process by performing the RACH process associated with the beam for which the measurement results are good.

[0213] Now, the Transmission Configuration Indicator (TCI) state is described. The TCI state can be configured per core set of the control channel, and parameters for determining the reception (Rx) beam of the terminal can be determined based on the TCI state.

[0214] For each downlink bandwidth portion (DL BWP) of a serving cell, the terminal may be configured with three or fewer core sets. Additionally, for each core set, the terminal may be provided with the following information.

[0215] 1) Coreset index p (e.g., one of 0 to 11, in which case the index of each coreset can be uniquely determined in the BWPs of a single serving cell),

[0216] 2) PDCCH DM-RS Scrambled Sequence Initialization Value,

[0217] 3) Interval of the core set in the time domain (can be given in symbol units),

[0218] 4) Resource block set,

[0219] 5) CCE-to-REG mapping parameters,

[0220] 6) Antenna port quasi-co-location (QCL) representing the quasi-co-location information of the DM-RS antenna port for PDCCH reception in each core set (from the set of antenna port quasi-co-locations provided by the upper layer parameter called 'TCI-State'),

[0221] 7) Indication of the existence or non-existence of a transmission configuration indication (TCI) field for a specific DCI format transmitted by PDCCH in the core set, etc.

[0222] QCL is explained. If the characteristics of the channel through which a symbol on one antenna port is transmitted can be inferred from the characteristics of the channel through which a symbol on another antenna port is transmitted, then the two antenna ports can be said to be in a quasi-common location (QCL). For example, if two signals (A and B) are transmitted from the same transmission antenna array with the same / similar spatial filter applied, the two signals may experience the same / similar channel conditions. From the perspective of a receiver, if it receives one of the two signals, it can detect the other signal by utilizing the channel characteristics of the received signal.

[0223] In this sense, the fact that A and B are QCL implies that A and B have undergone similar channel conditions, and therefore, the channel information estimated to detect A may also be useful for detecting B. Here, channel conditions can be defined by, for example, Doppler shift, Doppler spread, average delay, delay spread, spatial reception parameters, etc.

[0224] The 'TCI-State' parameter associates one or two downlink reference signals with the corresponding QCL type (QCL types A, B, C, and D are available; see Table 5).

[0225] [Table 5]

[0226]

[0227] Each 'TCI-State' may include parameters for establishing a quasi-coordinated locality (QCL) relationship between one or two downlink reference signals and the DM-RS port of the PDSCH (or PDCCH) or the CSI-RS port of the CSI-RS resource.

[0228] Meanwhile, in each DL BWP configured for the terminal in a single serving cell, the terminal may be provided with 10 or fewer search space sets. For each search space set, the terminal may be provided with at least one of the following information.

[0229] 1) search space set index s (0≤s<40), 2) association between core set P and search space set s, 3) PDCCH monitoring period and PDCCH monitoring offset (in slots), 4) PDCCH monitoring pattern within a slot (e.g., indicating the first symbol of the core set within the slot for PDCCH monitoring), 5) number of slots in which search space set s exists, 6) number of PDCCH candidates per CCE aggregation level, 7) information indicating whether search space set s is a CSS (common search space) or a USS (UE-specific search space), etc.

[0230] In NR, core set #0 can be configured by the PBCH (or terminal-specific signaling for handover, PSCell configuration, or BWP configuration). The search space (SS) set #0 configured by the PBCH may have different monitoring offsets (e.g., slot offset, symbol offset) for each associated SSB. This may be necessary to minimize the search space occasions that the terminal needs to monitor. Alternatively, it may be necessary to provide a beam sweeping control / data area capable of transmitting control / data according to each beam, so that communication with the terminal can be maintained even when the terminal's best beam changes dynamically.

[0231] FIG. 12 illustrates physical channels and general signal transmission.

[0232] Referring to FIG. 12, in a wireless communication system, a terminal receives information from a base station via a downlink (DL) and transmits information to the base station via an uplink (UL). The information transmitted and received by the base station and the terminal includes data and various control information, and various physical channels exist depending on the type / purpose of the information they transmit and receive.

[0233] When the power is turned on again after being off, or when a terminal newly enters a cell, it performs an initial cell search operation, such as synchronizing with the base station (S11). To do this, the terminal receives PSCH (Primary Synchronization Channel) and SSCH (Secondary Synchronization Channel) from the base station to synchronize with the base station and obtain information such as cell ID (cell identity). In addition, the terminal can obtain cell broadcast information by receiving PBCH (Physical Broadcast Channel) from the base station. Furthermore, during the initial cell search phase, the terminal can check the downlink channel status by receiving DL RS (Downlink Reference Signal).

[0234] (Initial) cell search can be described as a procedure in which a terminal acquires time and frequency synchronization with a cell to detect the cell ID of said cell. Cell search may be based on the primary synchronization signal and secondary synchronization signal of said cell, and the PBCH DMRS.

[0235] After completing the initial cell search, the terminal can obtain more specific system information by receiving the PDCCH (Physical Downlink Control Channel) and the corresponding PDSCH (Physical Downlink Control Channel) (S12).

[0236] Subsequently, the terminal may perform a Random Access Procedure to complete the connection to the base station (S13~S16). Specifically, the terminal transmits a preamble through a PRACH (Physical Random Access Channel) (S13) and receives a RAR (Random Access Response) for the preamble through a PDCCH and a corresponding PDSCH (S14). Subsequently, the terminal transmits a PUSCH (Physical Uplink Shared Channel) using scheduling information within the RAR (S15) and may perform a Contention Resolution Procedure such as a PDCCH and a corresponding PDSCH (which can be described as a process of receiving a contention resolution message) (S16).

[0237] When first connecting to a base station or when there are no radio resources available for signal transmission, the terminal may perform a Random Access Procedure (RACH) with respect to the base station. In this case, a 4-stage contention-based or Type-1 random access may include a first stage in which the terminal transmits a random access preamble (or Msg1) to the base station, a second stage in which the terminal receives a Random Access Response (RAR) (or Msg2) from the base station, a third stage in which the terminal transmits an uplink message (or Msg3) to the base station, and a fourth stage in which the terminal receives a contention resolution message (or Msg4) from the base station. Alternatively, a 2-stage contention-based or Type-2 random access may include a first stage in which the terminal transmits a random access preamble and an uplink message, etc., to the base station, and a second stage in which the terminal receives a random access response and a contention resolution message, etc., from the base station. A contention-free random access procedure may include only the first and second steps of a contention-based access procedure, and since no contention occurs between terminals, the third and fourth steps are not required.

[0238] The terminal can perform random access preamble or PRACH transmission to the base station based on random access opportunity (RO), preamble transmission power, etc., provided through SIB1 or dedicated RRC signaling. Here, the terminal can select an optimal SSB or CSI-RS (Channel Status Information-Reference Signal) and determine the RO and / or preamble index group associated with the selected SSB or CSI-RS. During the initial access process, the terminal can select the optimal SSB and the corresponding receive beam from among multiple SSBs corresponding to the base station's multi-beam sweeping. Meanwhile, after the initial access, when the terminal is in an RRC connection state, it can perform transmission beam and / or receive beam selection or change through a CSI measurement and reporting process based on the CSI-RS from the base station.

[0239] After the terminal transmits the preamble, it may monitor for RAR reception during a predetermined time interval. For example, the terminal may monitor a PDCCH scrambled with RA-RNTI and receive RAR through a PDSCH transmitted from a resource scheduled by the DCI within the PDCCH. The RAR may include a Random Access Preamble Identifier (RAPID), an Uplink Grant (UL Grant) for Msg3 scheduling, a Temporary Cell Identifier (Temporary C(Cell)-RNTI), a Timing Advance Command (TAC) determined based on the preamble reception timing, etc.

[0240] If the terminal fails to successfully receive the RAR, it may retransmit the preamble by applying power ramping, etc.

[0241] When the terminal successfully receives the RAR, it may transmit Msg3 based on the UL grants, etc. within the RAR. When Msg3 is transmitted, the terminal starts a contention resolution timer (CR timer) and may perform PDCCH monitoring based on C-RNTI to receive Msg4. If Msg4 is received while the CR timer is running, the terminal may determine that contention resolution has been successfully performed.

[0242] A terminal that has performed the procedure described above may subsequently perform PDCCH / PDSCH reception (S17) and PUSCH / PUCCH (Physical Uplink Control Channel) transmission (S18) as a general uplink / downlink signal transmission procedure. The control information transmitted by the terminal to the base station is referred to as UCI (Uplink Control Information). UCI includes HARQ ACK / NACK (Hybrid Automatic Repeat and reQuest Acknowledgement / Negative-ACK), SR (Scheduling Request), CSI (Channel State Information), etc. CSI includes CQI (Channel Quality Indicator), PMI (Precoding Matrix Indicator), RI (Rank Indication), etc. UCI is generally transmitted via PUCCH, but if control information and data need to be transmitted simultaneously, it may be transmitted via PUSCH. Additionally, the terminal may transmit UCI non-periodically via PUSCH in response to network requests / instructions. UCI may be transmitted repeatedly via PUCCH.

[0243] Meanwhile, control information transmitted by the terminal to the base station via the uplink (or received by the terminal from the base station) may include downlink / uplink ACK / NACK signals, CQI (Channel Quality Indicator), PMI (Precoding Matrix index), RI (Rank Indicator), etc. For example, in the case of a 3GPP LTE system, the terminal may transmit the control information such as the above-mentioned CQI / PMI / RI via PUSCH and / or PUCCH.

[0244] The table below shows an example of the DCI format.

[0245] [Table 6]

[0246]

[0247] Referring to Table 6 above, DCI formats 0_0, 0_1, and 0_2 may include resource information related to PUSCH scheduling (e.g., UL / SUL (Supplementary UL), frequency resource allocation, time resource allocation, frequency hopping, etc.), transmission block (TB) related information (e.g., MCS, NDI, RV, etc.), HARQ related information (e.g., process number, DAI (downlink assignment index), PDSCH-HARQ feedback timing, etc.), multi-antenna related information (e.g., DMRS sequence initialization information, antenna port, CSI request, etc.), and power control information (e.g., PUSCH power control, etc.), and the control information included in each DCI format may be predefined.

[0248] DCI format 0_0 is used for scheduling PUSCH in a cell. The information contained in DCI format 0_0 is transmitted after being CRC scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI.

[0249] DCI format 0_1 ​​is used to instruct a terminal on the scheduling of one or more PUSCHs in a cell, or on configured grant (CG) downlink feedback information. The information contained in DCI format 0_1 ​​is transmitted after being CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, or MCS-C-RNTI.

[0250] DCI format 0_2 is used for scheduling PUSCH in a cell. The information contained in DCI format 0_2 is transmitted after being CRC scrambled by C-RNTI, CS-RNTI, SP-CSI-RNTI, or MCS-C-RNTI.

[0251] Next, DCI formats 1_0, 1_1, and 1_2 may include resource information related to PDSCH scheduling (e.g., frequency resource allocation, time resource allocation, VRB-PRB mapping, etc.), transmission block (TB) related information (e.g., MCS, NDI, RV, etc.), HARQ related information (e.g., process number, DAI, PDSCH-HARQ feedback timing, etc.), multi-antenna related information (e.g., antenna port, TCI, SRS request, etc.), and PUCCH related information (e.g., PUCCH power control, PUCCH resource indicator, etc.), and the control information included in each DCI format may be predefined.

[0252] DCI format 1_0 is used for scheduling PDSCH in a single DL cell. The information contained in DCI format 1_0 is transmitted after being CRC scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI.

[0253] DCI format 1_1 is used for scheduling PDSCH in a single cell. The information contained in DCI format 1_1 is transmitted after being CRC scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI.

[0254] DCI format 1_2 is used for scheduling PDSCH in a single cell. The information contained in DCI format 1_2 is transmitted after being CRC scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI.

[0255] DCI format 1_3 is used for scheduling one PDSCH in a single cell or for scheduling multiple PDSCHs in multiple cells, each having one PDSCH. The information contained in DCI format 1_3 is transmitted after being CRC scrambled by C-RNTI or MCS-C-RNTI.

[0256] <LDPC(Low Density Parity Check) 코드>

[0257] One of the key components of the 5G NR standard is the use of advanced error correction codes, such as LDPC codes, to ensure stable transmission over wireless channels. 5G must support high throughput of up to 20 Gbps, various block sizes with different code rates for data channels, and Hybrid Automatic Repeat Request (HARQ).

[0258] LDPC codes provide a good solution that meets all requirements set by 3GPP. The base graph of 5G NR LDPC codes is structured, and the parity check matrix can efficiently support HARQ and rate compatibility. The features of this base graph allow for the support of any amount of transmitted information bits at various code rates across a wide range.

[0259] Base Graphs of 5G NR LDPC Codes

[0260] Figure 13 illustrates the structure of the basic graph of NR.

[0261] Referring to FIG. 13, two types of base graphs (BG), BG-1 and BG-2, can be defined. The use of these BGs can be determined by the size of the required information bits and the code transmission rate. For example, BG-1 consists of 46 rows and 68 columns, and the size of the information block is K = 22Z c And, BG-2 consists of 42 rows and 52 columns, and K = 10Z c It can be. Here, Z c is the size of the lifting matrix, and Table 7 below exemplifies the set of lifting sizes defined for 5G NR.

[0262] [Table 7]

[0263]

[0264] The block structure of BG-1 and BG-2 is identical. The columns include Information Columns, Core Parity Columns, and Extension Parity Columns. The rows are divided into Core Check Rows and Extension Check Rows.

[0265] [Table 8]

[0266]

[0267] The sub-matrix E is a dual diagonal matrix useful for low-complexity encoding of LDPC. Each base graph has a total of 51 lifting sizes from 2 to 384.

[0268] According to the LDPC encoding procedure, 66Z c Generate the coded bits (for BG-1), and 50Z cGenerates coded bits (for BG-2). The coded bits from BG-1 and BG-2 are output in the order of systematic bits, core parity bits, and extended parity bits.

[0269] <NR LDPC 코드에서 레이트 매칭(Rate Matching in NR LDPC Codes)>

[0270] N coded bits generated according to the LDPC encoding procedure are subjected to a rate matching process to select G coded bits in order to match the size of the resource allocated for transmission block transmission and the modulation order. For the rate matching process, the generated coded bits are stored in a circular buffer, and the initial bit location of the coded bits to be transmitted is selected based on the redundancy version (RV) index of the HARQ.

[0271] [Table 9]

[0272]

[0273] <NR LDPC 코드에서 인터리빙(Interleaving in NR LDPC Codes)>

[0274] In high-order QAM modulation schemes of 16QAM (order 4) or higher, the bit-by-bit transmission reliability of the n-bit tuples that determine the QAM symbol varies depending on the bit position. Generally, gray mapping is applied so that the MSB has higher reliability than the LSB.

[0275] Figure 14 illustrates the output of an interleaver in the case of 16QAM modulation.

[0276] Referring to FIG. 14, LDPC codeword code bits are written row by row starting from row 1, and the output of the block interleaver is read column by column starting from the left column and transmitted after 16QAM modulation. Therefore, the code bits mapped to rows 1 and 2 are located at the MSB of the 4-bit tuple that determines the 16QAM symbol, and are transmitted more reliably in the QAM symbol of the Gray mapping. This operation ensures that systematic bits with higher priority among the LDPC code bits are transmitted more reliably.

[0277] <NR에서 레이어 맵핑(Layer mapping in NR)>

[0278] In MIMO 2 codeword transmission, each layer is divided into two sets, and data is transmitted to an independent MCS for each set. For example, a separate TB is allocated for each layer set, and independent codewords are transmitted for each layer set after channel encoding.

[0279] The table below shows the codeword-to-layer mapping relationship, where a single codeword is transmitted at ranks below 4. In this case, modulation symbols are mapped alternately at each layer to maximize diversity gain.

[0280] [Table 10]

[0281]

[0282] <NR에서 변조 맵퍼(modulation mapper)>

[0283] In QPSK modulation, a pair of bits, b(2i) and b(2i+1), is mapped to complex value modulation symbols d(i) as shown in the equation below.

[0284] [Equation 3]

[0285]

[0286] In 16QAM modulation, the 4 bits, b(4i), b(4i+1), b(4i+2), and b(4i+3), are mapped to the complex value modulation symbols d(i) as shown in the equation below.

[0287] [Equation 4]

[0288]

[0289] In 64QAM modulation, the 6 bits, b(6i), b(6i+1), b(6i+2), b(6i+3), b(6i+4), and b(6i+5), are mapped to the complex value modulation symbols d(i) as shown in the equation below.

[0290] [Equation 5]

[0291]

[0292] Here, even-numbered input bits are mapped to the I-channel (in phase channel), and odd-numbered input bits are mapped to the Q-channel (quadrature channel).

[0293] In 16QAM modulation, b(4i) and b(4i+1) are transmitted more reliably than b(4i+2) and b(4i+3) in the I-channel and Q-channel, respectively.

[0294] To enable reasonable battery consumption when BA (bandwidth adaptation) is configured, only one uplink BWP and one downlink BWP or only one downlink / uplink BWP pair for each uplink carrier can be enabled at a time within an active serving cell, and all other BWPs configured in the terminal are disabled. In the disabled BWPs, the terminal does not monitor the PDCCH and does not transmit on the PUCCH, PRACH, and UL-SCH.

[0295] Regarding the BA, the terminal's receive and transmit bandwidths do not need to be as wide as the cell's bandwidth and can be adjusted: the width can be commanded to change (e.g., contracting during periods of low activity to save power), the position in the frequency domain can be shifted (e.g., to increase scheduling flexibility), and the subcarrier spacing can be commanded to change (e.g., to allow different services). A subset of the cell's total cell bandwidth is referred to as the bandwidth part (BWP), and the BA is obtained by setting the BWP(s) to the terminal and informing the terminal of which of the set BWPs is currently active. Once the BA is set, the terminal only needs to monitor the PDCCH on one active BWP. For example, there is no need to monitor the PDCCH across the cell's entire downlink frequency. A BWP inactive timer (independent of the aforementioned DRX inactive timer) is used to switch an active BWP to a default BWP: the timer is restarted when PDCCH decoding is successful, and when the timer expires, switching to the default BWP occurs.

[0296] In the following, the integrated access and backhaul link (IAB) will be described. For the convenience of explanation, the proposed method will be described based on the new RAT (NR) system, but the scope of systems to which the proposed method applies can be extended to other systems, such as 3GPP LTE / LTE-A systems, in addition to NR systems.

[0297] One of the potential technologies aimed at enabling future cellular network deployment scenarios and applications is support for wireless backhaul and relay links, which enables flexible and very dense deployment of NR cells without the need to proportionally densify the transport network.

[0298] With the expected availability of larger bandwidths in NR compared to LTE (e.g., millimeter wave spectrum) along with the native deployment of massive MIMO or multi-beam systems, opportunities for the development and deployment of integrated access and backhaul links are created. This allows for easier deployment of dense networks of self-backhauled NR cells in a more integrated manner by establishing multiple control and data channels / procedures defined to provide access to terminals. Such systems are referred to as integrated access and backhaul links (IABs).

[0299] The present disclosure defines the following.

[0300] - AC(x): Access link between node(x) and terminal(s).

[0301] - BH(xy): Backhaul link between node (x) and node (y).

[0302] In this case, the node may refer to a DgNB (donor gNB) or a relay node (relay node: RN). Here, the DgNB or donor node may be a gNB that provides the function of supporting backhaul for IAB nodes.

[0303] When relay node 1 and relay node 2 exist, and relay node 1 is connected to relay node 2 via a backhaul link to relay data transmitted to and received by relay node 2, relay node 1 is called the parent node of relay node 2, and relay node 2 is called the child node of relay node 1.

[0304] 6G Network Structure

[0305] FIG. 15 illustrates an exemplary flexible network topology to which the embodiments of the present specification can be applied.

[0306] Referring to Fig. 15, a network topology in which the split wireless access network (RAN) is configured more flexibly and resiliently can be considered to compensate for incomplete areas of network coverage.

[0307] To this end, various nodes such as IAB nodes, relays, and RF repeaters, as shown in the example of Fig. 15, may be applied, and a non-terrestrial network (NTN) may be integrated.

[0308] For example, an IAB node may correspond to a node providing wireless backhaul. For example, a relay may refer to any intermediate point, and in the case of a sidelink relay where a terminal functions as a relay, it may collectively refer to a terminal-to-network (U2N) relay and a terminal-to-terminal (U2U) relay.

[0309] For example, an RF repeater may correspond to a node that performs the functions of simple signal amplification and forwarding, and in the case of a network-controlled repeater (NCR), it may not only perform signal amplification and forwarding but also adjust transmission and reception settings based on information provided by the network.

[0310] For example, NTN nodes can correspond to satellites or aircraft that provide NTN coverage that is difficult for terrestrial networks to provide. In addition to these examples, various intermediate points can be introduced to improve the network topology.

[0311] In FIG. 15, the split RAN can support the division of a base station into one centralized unit (CU) and one or more distributed units (DU). The CU and DU may correspond to logical units. The CU may be further divided into a control plane (CP) portion and one or more user planes (UP) portions. Since a failure in the CU-CP affects the CU-UP as well as the DU, various intermediate points may be introduced to compensate for this.

[0312] An intermediate point may correspond to a terminal or a base station depending on its relative relationship with other nodes. For example, an IAB node may include a mobile-termination (MT) portion and a DU. The MT can connect the IAB node to a donor node. The DU of the IAB node may serve other terminals or connect to other IAB nodes to provide multi-hop wireless backhaul to terminals. In other words, an IAB node may correspond to a base station in its relative relationship with user-side nodes and to a terminal in its relative relationship with network-side nodes.

[0313] In the following examples, the description of a terminal may apply equally to an intermediate point corresponding to a terminal in relation to a network-side endpoint, as well as to a user-side endpoint. Similarly, in some examples of this specification, the description of a base station may apply equally to an intermediate point corresponding to a base station in relation to a user-side endpoint, as well as to a network-side endpoint. However, in most cases where there is no additional description of the operation of three or more entities, the communication entities in this specification may be briefly described by the term terminal and / or base station (or first node and / or second node). Here, the term terminal and / or base station (or first node and / or second node) may be interpreted to include or replace any endpoint or any intermediate point in relation to other nodes.

[0314] In some of the examples of the present specification below, for the sake of brevity of description, the subject of the operation may be referred to as a base station and / or terminal (or a first node and / or a second node). Additionally, the term base station and / or terminal (or a first node and / or a second node) may be interpreted or substituted as in the following examples: for example, the base station (or the first node) and the terminal (or the second node) may correspond to a first end point and a second end point, respectively; may correspond to an end point and an intermediate point, respectively; may correspond to an intermediate point and an end point, respectively; and may correspond to a first intermediate point and a second intermediate point, respectively.

[0315] In this specification, there may be no intermediate points between the base station and the terminal, or there may be one or more. If intermediate points exist, the intermediate points may correspond to IAB nodes, relays, RF repeaters, NTN (non-terrestrial network) nodes, or nodes supporting other functions. The intermediate points may be nodes with a fixed location or nodes with an indefinite location.

[0316] Now, a method for transmitting feedback information regarding the reception of low-quality data in a wireless communication system and a device utilizing said method will be described.

[0317] For example, when using LDPC channel coding with a 1 / 3 code rate for data transmission, 1) transmission to RV0 (RV index 0) includes all systematic bits, 2) transmission to RV1 (RV index 1) and RV3 (RV index 3) includes some systematic bits, and 3) transmission to RV2 (RV index 2) may not include systematic bits.

[0318] In addition, for example, when using LDPC channel coding with a 1 / 5 code rate, 1) transmission for RV0 includes all systemic bits, 2) transmission for RV3 includes some systemic bits, and 3) transmission for RV1 and RV2 may not include systemic bits.

[0319] Figure 16 illustrates the transmitted coded bits according to the RV when using a 1 / 3 code rate.

[0320] Referring to FIG. 16, the entire coded bits are d0, d1, d2, d, d N-1 Figures 16 (a) to (d) illustrate the positions of the coded bits transmitted according to the RV value among the total coded bits.

[0321] The RV index can be described as an indicator that determines which part of the encoded bits to select and transmit when performing rate matching on the transmitted data (e.g., Transport Block). The receiver (UE or gNB) can increase the probability of successful decoding by using an incremental redundancy (IR) method.

[0322] In NR, for example, four RV indices, RV0, RV1, RV2, and RV3, can be used.

[0323] In an initial transmission such as that shown in FIG. 16 (a), the transmitter (gNB or UE) typically transmits data using RV index 0 (RV0). RV0 may contain a set of bits that is most advantageous for independently decoding the transmission block. The data associated with RV0 may include all systematic bits and some parity bits to be received by the terminal. The systematic bits may be the portion containing the data to be transmitted to the terminal, and the parity bits may be bits added to detect and correct / recover errors. The parity bits may be generated, for example, through a specific algorithm or encoding method based on the systematic bits.

[0324] The receiver receives the above data and checks for errors, for example, through a Cyclic Redundancy Check (CRC), and if no error is found, it sends an ACK to the transmitter.

[0325] Then, the transmitter resets the corresponding HARQ process and clears the buffer. When this process transmits new data (transmission block) the next time, it uses RV0 again.

[0326] Conversely, if the receiver fails the CRC check, it sends a NACK to the transmitter; in this case, the transmitter performs a retransmission using the same HARQ process ID. At this time, the transmitter sends bits different from the previous transmission, allowing the receiver to combine previously stored (buffered) error data with the currently received retransmission data, thereby enhancing error correction capabilities.

[0327] In other words, when retransmitting, the transmitter transmits data associated with an RV index other than RV0, as shown in (b), (c), and (d) of FIG. 16. For example, the transmitter may transmit data in the order of RV0, RV2, RV3, RV1, or in the order of RV0, RV2, RV1, RV3.

[0328] Data associated with an RV index other than RV0 may include some parity bits without including systemic bits to be received by the terminal, or may include some systemic bits to be received by the terminal and some parity bits.

[0329] For example, as shown in FIG. 16 (b), data related to RV1 may include some systematic bits and some parity bits to be received by the terminal. As shown in FIG. 16 (c), data related to RV2 may include some parity bits and not include systematic bits to be received by the terminal. As shown in FIG. 16 (d), data related to RV3 may include some systematic bits and some parity bits to be received by the terminal.

[0330] However, FIG. 16 is merely an example for illustrative purposes and is not a limitation. For example, the data related to RV1 may also include some parity bits and not include systomic bits to be received by the terminal.

[0331] If a terminal fails to properly receive the systomic bits among the coded bits for a transport block to be received from a base station, the terminal may not be able to properly decode information using only non-systomic bits (e.g., parity bits).

[0332] In other words, decoding of information cannot be performed or may be difficult with only the reception of parity bits without the reception of systomic bits.

[0333] When a terminal receives a transmission block from a base station, it may receive an initial transmission (or a transmission for systomic bits, such as a transmission related to RV0) in a very poor channel environment. In this case, the terminal may fail to receive the transmission (the transmission related to RV0).

[0334] In such cases, according to the prior art, the terminal may attempt to decode by receiving a retransmission having a different RV index (e.g., RV2) for the transmission block and combining it with the initial transmission.

[0335] However, if the information received in the initial transmission is difficult to use meaningfully for decoding due to the poor channel environment, the information from the initial transmission may not be helpful for decoding, or in some cases, it may be better not to use it for combination. Additionally, if the information in the initial transmission is of such low quality that it is difficult to use for decoding, it may be difficult to successfully decode it through combination even if a retransmission related to another RV index is received.

[0336] Figure 17 illustrates the case where the receiver receives the first transmission and the second transmission of the transmitter.

[0337] Referring to FIG. 17, if the receiver receives the coded bits for RV0 through the first transmission of the transmitter but the reception quality is very low, even if it receives the coded bits for RV2 through the second transmission, it may not be able to successfully perform decoding because it does not receive assistance in decoding from the RV0 transmission.

[0338] Considering these issues, the present disclosure proposes a method in which, when a terminal determines that the reception quality of coded bits received is very low and difficult to use for decoding, it reports this information to a base station so that the base station can retransmit the coded bits for the same RV. From this, the terminal is able to use the systomic bits essential for successful decoding for decoding.

[0339] For example, according to the prior art, if a terminal receives coded bits for RV0 but receives them with a quality so low that they are difficult to use for decoding, the base station may perform retransmission with a different RV because the terminal has received coded bits for RV0. In this case, even if the terminal receives the retransmitted coded bits, it is unable to properly perform decoding because the systomic bits included in RV0 do not aid in decoding.

[0340] Such problems can occur, for example, in the following environments.

[0341] In cases where the channel change rate is high, such as in high-mobility or high-frequency range environments, the channel conditions deteriorate compared to the MCS applied by the base station, resulting in the reception of bits coded with very low quality.

[0342] In cases where short-term interference occurs frequently, such as in dynamic / flexible TDD environments or SBFD / SSFD environments, the channel conditions deteriorate compared to the MCS applied by the base station, and bits coded with very low quality may be received.

[0343] In the present disclosure, if a terminal determines that the reception quality of coded bits received is very low and difficult to use for decoding, it reports this information to a base station so that the base station can retransmit the coded bits for the same RV. This is explained in detail below.

[0344] <5.1. Feedback Information Regarding Low-Quality Reception>

[0345] This section proposes a method for configuring low-quality reception information transmitted by a terminal to a base station.

[0346] If the terminal receives coded bits of very low quality, it may transmit information about this to the base station. Upon receiving this information, the base station, based on the information transmitted by the terminal, determines / recognizes that the (some) coded bits received by the terminal are of such low quality that they are difficult to use for decoding, and based on this, can transmit the coded bits necessary for the terminal's decoding to the terminal.

[0347] Information regarding such low-quality reception can be configured, for example, as follows.

[0348] Approach A: Feedback on low-quality received information

[0349] Information indicating that the coded bits transmitted from the base station to the terminal have been transmitted with such low quality that they are difficult to use for decoding can be transmitted from the terminal to the base station.

[0350] After receiving bits coded for a TB (transmission block) to be received from a base station, the terminal may transmit information about the channel quality of the received coded bits to the base station. Alternatively, after receiving bits coded for a TB (transmission block) to be received from a base station, the terminal may transmit low-quality reception information to the base station indicating that the received coded bits were received at a quality so low that they are difficult to use for decoding.

[0351] This information (low-quality received information) can be transmitted in units of TB (transmission block) / CB (code block) / CBG (code block group) received by the terminal from the base station. For example, this information can be transmitted in units where the terminal transmits ACK / NACK information to the base station.

[0352] This information may be transmitted to the TB / CB / CBGs that are the subject of the HARQ-ACK feedback when the terminal performs HARQ-ACK feedback to the base station. Alternatively, this information may be transmitted to only some of the TB / CB / CBGs that are the subject of the HARQ-ACK feedback. For example, this information may be transmitted only to the TB / CB / CBGs that receive NACK feedback through the HARQ-ACK feedback.

[0353] This information may be transmitted in addition to and / or independently of the HARQ-ACK information when the terminal performs HARQ-ACK feedback to the base station.

[0354] When HARQ-ACK feedback for multiple TBs is performed to a base station at once, this information can be transmitted in units of multiple TBs.

[0355] For example, this information can be transmitted in units of TBs scheduled by the same DCI.

[0356] Alternatively, for example, for TBs where NACK is fed back, this information can be transmitted in units of multiple TBs.

[0357] At this time, the terminal may determine that the received coded bits have been received with such low quality that they are difficult to use for decoding. For example, it may determine this as in Section 5.4 below. In other words, the terminal may perform a determination on the reception quality of the received coded bits as in Section 5.4 below in order to feed back low-quality reception information to the base station.

[0358] Low-quality reception information can be configured more specifically as follows.

[0359] Method A-1. A status corresponding to 'low quality reception' information may be added to the HARQ-ACK feedback information.

[0360] For example, the HARQ-ACK information that the terminal feeds back to the base station may include information indicating 'low quality reception'. To this end, a status indicating 'low quality reception' may be added to the HARQ-ACK information transmitted by the terminal to the base station.

[0361] With existing HARQ-ACK information, ACK or NACK can be fed back in TB or CBG units, but by applying this method, ACK, NACK, or low-quality reception can be fed back through HARQ-ACK information.

[0362] The terminal can feed back to the base station one of the statuses of ACK, NACK, or low quality reception for the received TB / CB / CBG.

[0363] If the terminal provides feedback of a state corresponding to 'low quality reception' for a specific TB / CB / CBG, this may mean that the reception of the TB / CB / CBG is NACK. That is, it may mean that a NACK occurred during the reception of the TB / CB / CBG and that the received coded bits were received as low quality.

[0364] Meanwhile, if the terminal feeds back a 'NACK' to the TB / CB / CBG that is not in a state corresponding to 'low quality reception', it may mean that a NACK occurred during the reception of the TB / CB / CBG and that the received coded bits were received with a quality suitable for decoding. Alternatively, if the terminal feeds back a 'NACK' to the TB / CB / CBG that is not in a state corresponding to 'low quality reception', it may mean that a NACK occurred during the reception of the TB / CB / CBG, and that information regarding the reception quality is not included.

[0365] Additionally / independently, information indicating 'high quality reception' may be included in the HARQ-ACK information that the terminal feeds back to the base station. To this end, a state indicating 'high quality reception' may be added to the HARQ-ACK information that the terminal transmits to the base station. The terminal may feed back to the base station one of the states of ACK, NACK, high quality reception, and / or low quality reception for the received TB / CB / CBG.

[0366] When the terminal provides feedback on a state corresponding to 'high quality reception' for a specific TB / CB / CBG, this may mean that the reception of the TB / CB / CBG is an ACK. That is, it may mean that an ACK occurred for the reception of the TB / CB / CBG, and that the received coded bits were received with sufficient quality compared to the applied MCS.

[0367] In this embodiment, when the terminal provides feedback of a state corresponding to 'low quality reception' for a specific TB / CB / CBG, this may mean that the reception of the TB / CB / CBG is NACK. That is, it may mean that a NACK occurred during the reception of the TB / CB / CBG and that the received coded bits were received as low quality.

[0368] Meanwhile, if the terminal feeds back an 'ACK' to the TB / CB / CBG that is not in a state corresponding to 'high-quality reception', it may mean that an ACK occurred for the reception of the TB / CB / CBG and that the received coded bits were received with appropriate reception quality. Alternatively, if the terminal feeds back an 'ACK' to the TB / CB / CBG that is not in a state corresponding to 'high-quality reception', it may mean that an ACK occurred for the reception of the TB / CB / CBG, and that information regarding reception quality is not included.

[0369] Meanwhile, if the terminal feeds back a 'NACK' to the TB / CB / CBG that is not in a state corresponding to 'low quality reception', it may mean that a NACK occurred during the reception of the TB / CB / CBG and that the received coded bits were received with a quality suitable for decoding. Alternatively, if the terminal feeds back a 'NACK' to the TB / CB / CBG that is not in a state corresponding to 'low quality reception', it may mean that a NACK occurred during the reception of the TB / CB / CBG, and that information regarding the reception quality is not included.

[0370] Method A-2. In addition to HARQ-ACK feedback information, 'low quality reception' information may be transmitted.

[0371] 'Low quality reception' information may be transmitted in addition to / independently of the existing HARQ-ACK information that the terminal feeds back to the base station.

[0372] Through existing HARQ-ACK information, the status corresponding to ACK or NACK can be fed back at the TB or CBG / CB level. Through 'poor quality reception' information, the status corresponding to poor quality reception or not poor reception can be fed back at the TB / CB / CBG level.

[0373] In this case, if the terminal provides feedback of a state corresponding to 'low quality reception' for a specific TB / CB / CBG, this may mean that the received coded bits were received as low quality.

[0374] Meanwhile, if the terminal provides feedback to TB / CB / CBG that corresponds to a 'reception that is not of low quality,' this may mean that the received coded bits were received with a quality that can be used for decoding.

[0375] At this time, the terminal can provide feedback on whether the received coded bits are 'low quality received' through 'low quality received' information only when it provides feedback on NACK through HARQ-ACK information for a specific TB / CB / CBG. When the terminal provides feedback on ACK through HARQ-ACK information for a specific TB / CB / CBG, it can provide feedback on a state corresponding to 'non-low quality received' through 'low quality received' information.

[0376] Additionally / independently, through 'low-quality reception' information, a status corresponding to high-quality reception or non-high-quality reception can be fed back in TB / CB / CBG units.

[0377] In this case, if the terminal provides feedback of a state corresponding to 'high quality reception' for a specific TB / CB / CBG, this may mean that the received coded bits were received with sufficient quality compared to the applied MCS.

[0378] Meanwhile, if the terminal provides feedback to TB / CB / CBG that corresponds to a 'reception of poor quality,' this may mean that the received coded bits were received with a quality suitable for reception.

[0379] At this time, when the terminal feeds back an ACK through HARQ-ACK information for a specific TB / CB / CBG, a state corresponding to high-quality reception or non-high-quality reception of the received coded bits can be fed back through 'low-quality reception' information.

[0380] When the terminal feeds back a NACK via HARQ-ACK information for a specific TB / CB / CBG, a state corresponding to a low-quality reception or a non-low-quality reception may be fed back via 'low-quality reception' information. Meanwhile, when the terminal feeds back an ACK via HARQ-ACK information for a specific TB / CB / CBG, a state corresponding to a high-quality reception or a non-high-quality reception may be fed back via 'low-quality reception' information. That is, depending on the information fed back via HARQ-ACK information, the information implied by the value indicated by 'low-quality reception' information may vary. When a NACK is fed back via HARQ-ACK information, the two states indicated by 'low-quality reception' information correspond to a low-quality reception and a non-low-quality reception, respectively, and when an ACK is fed back via HARQ-ACK information, the two states indicated by 'low-quality reception' information correspond to a high-quality reception and a non-high-quality reception, respectively.

[0381] Method A-3. TB / CB / CBG information corresponding to 'low quality reception' may be transmitted.

[0382] Since cases where coded bits are received at a quality so low that they are difficult to use for decoding do not occur frequently, considering the feedback overhead, information about the TB / CB / CBG(s) received at a low quality may be transmitted in addition to / independently with the existing HARQ-ACK information that the terminal feeds back to the base station.

[0383] Information about TB / CB / CBG(s) may mean information that can distinguish the TB / CB / CBG(s) to which the terminal feeds back HARQ-ACK information to the base station.

[0384] For example, it can mean the TB / CB / CBG index.

[0385] Or, for example, when constructing a HARQ-ACK codebook with ACK / NACK information for TB / CB / CBGs, it may refer to the position / order of ACK / NACK information within the HARQ-ACK codebook.

[0386] Or it can mean the DAI value.

[0387] In this case, the terminal can transmit information to the base station regarding the TB / CB / CBG received as low quality among all TB / CB / CBGs that transmit HARQ-ACK feedback information to the base station.

[0388] Alternatively, the terminal may transmit to the base station information about the TB / CB / CBG received as low quality among the TB / CB / CBGs that transmit NACK information to the base station through HARQ-ACK feedback.

[0389] In this case, if the terminal provides feedback that a specific TB / CB / CBG is a TB / CB / CBG received with low quality, this may mean that the received coded bits were received with low quality.

[0390] Meanwhile, if the terminal does not provide feedback that a specific TB / CB / CBG is a TB / CB / CBG received with low quality, this may mean that the received coded bits were received with a quality that can be used for decoding.

[0391] At this time, the TB / CB / CBG may be indicated as a TB / CB / CBG received with low quality only when the terminal feeds back a NACK through HARQ-ACK information for a specific TB / CB / CBG.

[0392] Approach B: Feedback of RV information requiring retransmission

[0393] If some coded bits received by the terminal from the base station are received with such low quality that they are difficult to use for decoding, the terminal can transmit information about the RV index that requires retransmission for successful decoding to the base station.

[0394] In this case, RV index information required for decoding the corresponding CB / CBG / TB in TB / CB / CBG units can be transmitted to the base station.

[0395] When PDSCH is transmitted repeatedly, the RV index may refer to the RV index applied in the first slot where the PDSCH repetition is performed.

[0396] This information may be transmitted to the TB / CB / CBGs that are the subject of the HARQ-ACK feedback when the terminal performs HARQ-ACK feedback to the base station. Alternatively, this information may be transmitted to only some of the TB / CB / CBGs that are the subject of the HARQ-ACK feedback. For example, this information may be transmitted only to the TB / CB / CBGs that receive NACK feedback through the HARQ-ACK feedback.

[0397] This information may be transmitted in addition to and / or independently of the HARQ-ACK information when the terminal performs HARQ-ACK feedback to the base station.

[0398] At this time, the terminal can determine information regarding an RV index that needs to be retransmitted because it is received with such low quality that it is difficult to use for decoding, as in Section 5.4 below. In other words, the terminal can perform a determination of the reception quality of the received coded bits as in Section 5.4 below in order to feed back information regarding an RV index that needs to be retransmitted to the base station.

[0399] When providing feedback on such information, that is, RV information requiring retransmission, the information may be configured as follows.

[0400] Method B-1. State(s) corresponding to the RV index information can be added to the HARQ-ACK feedback information.

[0401] The HARQ-ACK information fed back by the terminal to the base station may include information indicating the RV index for which retransmission is required. To this end, state(s) for indicating the RV index may be added to the HARQ-ACK information transmitted by the terminal to the base station.

[0402] While existing HARQ-ACK information allows for ACK or NACK to be fed back in TB or CBG units, applying this method allows for ACK, NACK, or one of multiple RV indexes to be fed back through HARQ-ACK information. For example, a state of ACK, NACK, RV0, RV1, RV2, or RV3 can be fed back.

[0403] The terminal can feed back an ACK, NACK, or a specific RV index to the base station for the received TB / CB / CBG.

[0404] In this case, the information that can be fed back through HARQ-ACK can be specifically configured as follows.

[0405] It can be composed of ACK, NACK, RV0, RV1, RV2, and RV3. Alternatively, since an RV index can be indicated when NACK occurs, it can be composed of states such as ACK, RV0, RV1, RV2, and RV3 by excluding the NACK state.

[0406] At this time, only RV0 and / or RV3, which are RV indices containing systomic bits, may be included in the state.

[0407] In this case, multiple RV indices may be mapped to the same state. For example, RV1 and RV2 may not be distinguished and may be indicated through a single state. In this case, it may consist of states such as ACK, RV0, RV3, and RV1 / 2. If RV1 / 2 is fed back, it may mean information requiring retransmission for RV1 or RV2.

[0408] In this case, if there are more or fewer RV indices than the existing four, the number and value of RVs that can be indicated may differ.

[0409] When a specific RV index is transmitted to a base station as HARQ-ACK information for a specific TB / CB / CBG, this means that a NACK has occurred for the corresponding TB / CB / CBG, and that retransmission of the corresponding RV index is required for reception of the corresponding TB / CB / CBG.

[0410] Method B-2. In addition to the HARQ-ACK feedback information, information regarding the RV index requiring retransmission may be transmitted.

[0411] In addition to the existing HARQ-ACK information that the terminal feeds back to the base station, information regarding the RV index that requires retransmission can be transmitted independently.

[0412] Through existing HARQ-ACK information, the status corresponding to ACK or NACK can be fed back in TB or CBG / CB units.

[0413] Through RV index information requiring retransmission, RV index information can be fed back in TB / CB / CBG units. Specifically, the information that can be fed back through RV index information requiring retransmission can be configured as follows.

[0414] It can be composed of states such as RV0, RV1, RV2, and RV3.

[0415] At this time, only RV0 and / or RV3, which are RV indices containing systomic bits, may be included in the state.

[0416] In this case, if there are more or fewer RV indices than the existing four, the number and value of RVs that can be indicated may differ.

[0417] If the terminal feeds back a specific RV index for a specific TB / CB / CBG, this may mean that transmission for that RV index is required during retransmission for decoding the received coded bits.

[0418] At this time, the terminal may also provide RV index information that requires retransmission only when providing NACK through HARQ-ACK information for a specific TB / CB / CBG.

[0419] Method B-3. Information about the RV index requiring retransmission is transmitted along with TB / CB / CBG information corresponding to 'low quality reception'.

[0420] Since cases where coded bits are received at a quality so low that they are difficult to use for decoding do not occur frequently, considering the feedback overhead, information about the TB / CB / CBG(s) received at a low quality and information about the RV index required for decoding of the TB / CB / CBG may be transmitted in addition to / independently to the existing HARQ-ACK information that the terminal feeds back to the base station.

[0421] Information about TB / CB / CBG(s) may mean information that can distinguish the TB / CB / CBG(s) to which the terminal feeds back HARQ-ACK information to the base station.

[0422] For example, it can mean the TB / CB / CBG index.

[0423] Or, for example, when constructing a HARQ-ACK codebook with ACK / NACK information for TB / CB / CBGs, it may refer to the position / order of ACK / NACK information within the HARQ-ACK codebook.

[0424] Or it can mean the DAI value.

[0425] RV index information can be fed back through RV index information requiring retransmission. Specifically, the information that can be fed back through RV index information requiring retransmission can be configured as follows.

[0426] It can be composed of states such as RV0, RV1, RV2, and RV3.

[0427] At this time, only RV0 and / or RV3, which are RV indices containing systomic bits, may be included in the state.

[0428] If there are more or fewer RV indices than the existing four, the number and value of RVs that can be indicated may differ.

[0429] Approach C: Feedback on retransmission request information for RV0

[0430] A situation where it becomes problematic for some coded bits received by the terminal from the base station to be of such low quality that they are difficult to use for decoding generally occurs in the case of transmitting RV0, which transmits systomic bits. Therefore, the terminal can transmit information to the base station that retransmission of RV0 is required.

[0431] In this case, request information for retransmission of RV0 can be transmitted to the base station for decoding the corresponding CB / CBG / TB in TB / CB / CBG units.

[0432] This information may be transmitted to the TB / CB / CBGs that are the subject of the HARQ-ACK feedback when the terminal performs HARQ-ACK feedback to the base station. Alternatively, this information may be transmitted to only some of the TB / CB / CBGs that are the subject of the HARQ-ACK feedback. For example, this information may be transmitted only to the TB / CB / CBGs that receive NACK feedback through the HARQ-ACK feedback.

[0433] This information may be transmitted in addition to and / or independently of the HARQ-ACK information when the terminal performs HARQ-ACK feedback to the base station.

[0434] This information may be transmitted only when performing HARQ-ACK feedback for RV0 or when performing HARQ-ACK feedback for the initial transmission.

[0435] At this time, the terminal can determine whether retransmission is required because RV0 is received with such low quality that it is difficult to use for decoding, as in Section 5.4 below. In other words, the terminal can perform a determination on the reception quality of the received coded bits, as in Section 5.4 below, in order to feed back information about the retransmission of RV0 to the base station.

[0436] This information can be structured more specifically as follows.

[0437] Method C-1. A state corresponding to 'retransmission for RV0' may be added to the HARQ-ACK feedback information.

[0438] The HARQ-ACK information fed back by the terminal to the base station may include information indicating that retransmission for RV0 is required. To this end, a state indicating that 'retransmission for RV0' is required may be added to the HARQ-ACK information transmitted by the terminal to the base station.

[0439] With existing HARQ-ACK information, ACK or NACK can be fed back in TB or CBG units, but by applying this method, one of the states of 'ACK', 'NACK', or 'retransmission for RV0' can be fed back through HARQ-ACK information.

[0440] The terminal can provide feedback to the base station for the received TB / CB / CBG, such as 'ACK', 'NACK', or 'retransmission for RV0'.

[0441] In this case, if 'retransmission for RV0' is transmitted to the base station as HARQ-ACK information for a specific TB / CB / CBG, this means that a NACK has occurred for the TB / CB / CBG and may mean that retransmission for RV0 is required for reception of the TB / CB / CBG.

[0442] Method C-2. In addition to the HARQ-ACK feedback information, information regarding 'retransmission for RV0' is transmitted.

[0443] In addition to / independently with the existing HARQ-ACK information that the terminal feeds back to the base station, information indicating that 'retransmission for RV0' is required may be transmitted.

[0444] Through existing HARQ-ACK information, the status corresponding to 'ACK' or 'NACK' can be fed back in TB or CBG / CB units.

[0445] Through the RV index information requiring retransmission, information that 'retransmission for RV0' or 'retransmission for another RV' is required can be fed back in TB / CB / CBG units.

[0446] In this case, if the terminal provides feedback of 'retransmission for RV0' for a specific TB / CB / CBG, this may mean that the received coded bits were received of low quality.

[0447] Meanwhile, if the terminal provides feedback to TB / CB / CBG for 'retransmission to another RV', this may mean that the received coded bits were received in a quality suitable for decoding.

[0448] At this time, the terminal can provide feedback of a state meaning 'retransmission for RV0' only when it provides feedback of a NACK through HARQ-ACK information for a specific TB / CB / CBG.

[0449] Meanwhile, when the terminal feeds back an ACK through HARQ-ACK information for a specific TB / CB / CBG, it may feed back a status meaning 'retransmission to another RV'. Alternatively, the terminal may feed back RV index information requiring retransmission only when it feeds back a NACK through HARQ-ACK information for a specific TB / CB / CBG.

[0450] Method C-3. TB / CB / CBG information requiring 'retransmission to RV0' can be transmitted.

[0451] Since it is unlikely that cases where coded bits are received at a quality so low that they are difficult to use for decoding will occur frequently, considering the feedback overhead, information about TB / CB / CBG(s) requiring 'retransmission for RV0' may be transmitted in addition to / independently with the existing HARQ-ACK information that the terminal feeds back to the base station.

[0452] Information about TB / CB / CBG(s) may mean information that can distinguish the TB / CB / CBG(s) to which the terminal feeds back HARQ-ACK information to the base station.

[0453] For example, it can mean the TB / CB / CBG index.

[0454] Or, for example, when constructing a HARQ-ACK codebook with ACK / NACK information for TB / CB / CBGs, it may refer to the position / order of ACK / NACK information within the HARQ-ACK codebook.

[0455] Or it can mean the DAI value.

[0456] In this case, the terminal can transmit to the base station information regarding the TB / CB / CBG for which retransmission for RV0 is required among all TB / CB / CBGs that transmit HARQ-ACK feedback information to the base station.

[0457] Alternatively, the terminal may transmit to the base station information regarding the TB / CB / CBG for which retransmission for RV0 is required among the TB / CB / CBGs that transmit NACK information to the base station through HARQ-ACK feedback.

[0458] In this case, if the terminal feeds back a specific TB / CB / CBG as a TB / CB / CBG that requires retransmission to RV0, this may mean that the received coded bits were received of low quality.

[0459] Meanwhile, if the terminal does not provide feedback that a specific TB / CB / CBG is a TB / CB / CBG for which retransmission to RV0 is required, this may mean that the received coded bits were received in a quality suitable for decoding.

[0460] At this time, only when the terminal feeds back a NACK through HARQ-ACK information for a specific TB / CB / CBG, the TB / CB / CBG can be indicated as a TB / CB / CBG for which retransmission to RV0 is required.

[0461] Low-quality reception information transmitted by the above terminal to the base station may be transmitted combined with DCI missing (or DTX) information.

[0462] DCI missing or DTX information is information indicating that the terminal has not received a DCI scheduling a PDSCH from the base station.

[0463] When providing feedback on the above low-quality reception information, DCI missing or DTX information can be provided through the feedback information.

[0464] When information regarding a low-quality reception is indicated through a specific state of the HARQ-ACK information, the specific state of the HARQ-ACK information may signify a low-quality reception, and another specific state may signify DCI missing or DTX information. For example, the HARQ-ACK information may consist of 2 bits and provide feedback on one of the states: 'ACK', 'NACK', 'low-quality reception', or 'DCI missing / DTX'. In this case, the state signifying 'low-quality reception' may be replaced with a state requesting 'retransmission of RV0'.

[0465] Alternatively, in this case, if low-quality reception information is fed back in addition to or independently of existing HARQ-ACK information, a specific state of the low-quality reception information may indicate DCI Missing or DTX information. For example, the low-quality reception information may consist of 2 bits and feed back one of the states 'RV0', 'RV3', 'other RV', or 'DCI Missing / DTX'. In this case, 'RV0' and 'RV3' may indicate information that retransmission using RV0 and RV3, respectively, is required upon retransmission. 'Other RV' may indicate information that retransmission using an RV other than RV0 or RV3 is required upon retransmission, or that the received coded bits are received at a quality suitable for decoding and no specific RV is required.

[0466] <5.2. Method for Determining Whether to Perform Feedback Regarding Low-Quality Receipts>

[0467] This section proposes a method and conditions for determining whether a terminal performs a feedback operation regarding information related to low-quality reception to a base station.

[0468] The terminal can transmit information to the base station regarding cases where the coded bits it receives are received with very low quality, as described in Section 5.1 above.

[0469] This information may be included in the HARQ-ACK information or additionally transmitted in the HARQ-ACK information when the terminal transmits HARQ-ACK information for TB / CB / CBG received from the base station.

[0470] When a terminal transmits HARQ-ACK information to a base station, it may not always transmit information related to low-quality reception.

[0471] Cases where coded bits are received at a quality so low that they are difficult to use for decoding may not occur frequently, and the necessity of such an operation may vary depending on the cell's operating method and the terminal's location / channel conditions. Therefore, considering feedback overhead, the terminal may determine whether to transmit information related to low-quality reception based on the base station's instructions, conditions, judgments, etc., and perform the transmission operation as follows.

[0472] Approach A: Decision based on configuration / indication from the base station.

[0473] When the terminal receives a setting / instruction from the base station for a feedback operation of low-quality reception information, it transmits (or can transmit) information related to low-quality reception to the base station.

[0474] When the terminal transmits HARQ-ACK information for TB / CB / CBG received from the base station based on the settings / instructions from the base station, the terminal may include low-quality reception information in the HARQ-ACK information or transmit it additionally in the HARQ-ACK information.

[0475] At this time, the terminal can receive setting / instruction information regarding the feedback operation of such low-quality received information from the base station as follows.

[0476] Method A-1. The terminal can receive feedback operation information for low-quality received information from the base station semi-statically through signaling such as RRC and / or MAC-CE.

[0477] The configuration information for the feedback operation information of such low-quality received information can be applied equally to all PDSCH / TBs received by the terminal.

[0478] And / or in the case of SPS-PDSCH, feedback operation information for low-quality received information can be set independently for each SPS-PDSCH setting.

[0479] And / or feedback operation information for low-quality received information can be set independently for SPS-PDSCH and PDSCH scheduled with DCI.

[0480] When the feedback operation for low-quality received information is configured through these settings, the terminal may include the HARQ-ACK information for the TB / CB / CBG received from the base station in the HARQ-ACK information or transmit it additionally to the HARQ-ACK information when transmitting it to the base station.

[0481] If the feedback operation for low-quality received information is not configured through these settings, the terminal may not transmit HARQ-ACK information for low-quality received information, and when transmitting HARQ-ACK information for TB / CB / CBG received from the base station, it may transmit only the existing HARQ-ACK information to the base station.

[0482] Method A-2. The terminal can receive feedback operation information for low-quality received information from the base station dynamically via DCI.

[0483] Instructions for feedback operation information regarding such low-quality received information are indicated through the DCI scheduling the PDSCH / TB, and can be applied to the PDSCH / TB scheduled by the said DCI.

[0484] When scheduling multiple PDSCHs and / or TBs through a single DCI, instructions for the same low-quality received information feedback operation information may be applied to the multiple PDSCHs and / or TBs scheduled by the DCI. Alternatively, when scheduling multiple PDSCHs and / or TBs through a single DCI, instructions for the low-quality received information feedback operation information may be applied independently for each of the multiple PDSCHs and / or TBs scheduled by the DCI.

[0485] Additionally, this operation can be applied in conjunction with 'Method A-1'.

[0486] For example, when a terminal receives feedback operation information for low-quality received information semi-statically from a base station via signaling such as RRC and / or MAC-CE, it may additionally receive dynamic instructions via DCI regarding whether to perform feedback operation for low-quality received information. If the terminal receives instructions regarding feedback operation for low-quality received information via DCI, it performs the feedback operation for low-quality received information. If the terminal does not receive instructions regarding feedback operation for low-quality received information via DCI, it determines that it does not perform the feedback operation for low-quality received information. If the terminal does not receive information regarding feedback operation for low-quality received information semi-statically from a base station via signaling such as RRC and / or MAC-CE, it may not receive instructions via DCI regarding whether to perform feedback operation for low-quality received information and may determine that it does not perform the feedback operation for low-quality received information.

[0487] Approach B: Judgment based on RV

[0488] A situation where it becomes problematic for some coded bits received by the terminal from the base station to be of such low quality that they are difficult to use for decoding generally occurs when transmitting systomic bits. Therefore, the terminal can perform a feedback operation for low-quality reception information when the transmission for RV0 is received at low quality or when the initial transmission is received at low quality.

[0489] In consideration of this, when the terminal receives a TB for RV0 and performs HARQ-ACK feedback thereon, it may transmit feedback regarding low-quality reception information to the base station. Alternatively, when the terminal receives an initial transmission and performs HARQ-ACK feedback thereon, it may transmit feedback regarding low-quality reception information to the base station.

[0490] Additionally, this operation can be applied in conjunction with the method proposed in the above 'Approach A'. In particular, it can be applied in conjunction with 'Method A-1' proposed in the above 'Approach A'.

[0491] For example, if a terminal receives feedback operation information for low-quality reception information semi-statically from a base station via signaling such as RRC and / or MAC-CE, the terminal can determine whether to perform feedback operation for low-quality reception information based on the RV applied to the received TB. If the terminal receives a TB with RV0 applied, the terminal performs feedback operation for low-quality reception information. If the terminal receives a TB with a different RV applied, the terminal determines that it does not perform feedback operation for low-quality reception information. If the terminal does not receive feedback operation information for low-quality reception information semi-statically from a base station via signaling such as RRC and / or MAC-CE, the terminal determines that it does not perform feedback operation for low-quality reception information regardless of the RV applied to the received TB.

[0492] Approach C: Decision based on ACK / NACK information

[0493] Low-quality reception information for coded bits received by the terminal is required only when decoding of the coded bits fails. Therefore, the terminal can transmit / transmit feedback on low-quality reception information to the base station when a NACK occurs upon reception of a TB transmitted from the base station.

[0494] Additionally, this operation can be applied in conjunction with the method proposed in the above 'Approach A'. In particular, it can be applied in conjunction with 'Method A-1' proposed in the above 'Approach A'.

[0495] For example, if a terminal receives feedback operation information for low-quality received information semi-statically from a base station via signaling such as RRC and / or MAC-CE, the terminal can determine whether to perform feedback operation for low-quality received information based on whether the decoding of the received TB is successful (whether an ACK / NACK occurs). If the decoding of the received TB fails and a NACK occurs, the terminal performs feedback operation for low-quality received information. If the decoding of the received TB is successful and an ACK occurs, the terminal determines that it does not perform feedback operation for low-quality received information. If the terminal does not receive feedback operation information for low-quality received information semi-statically from a base station via signaling such as RRC and / or MAC-CE, the terminal determines that it does not perform feedback operation for low-quality received information regardless of whether the decoding of the received TB is successful.

[0496] <5.3. Method for Configuring UCI for Feedback on Low-Quality Reception>

[0497] This section proposes a method for configuring the UCI that a terminal transmits to a base station when the terminal provides feedback regarding low-quality reception information to the base station.

[0498] Low-quality received information transmitted by the terminal to the base station may be included in the HARQ-ACK information or additionally transmitted to the HARQ-ACK information when the terminal transmits HARQ-ACK information for TB / CB / CBG received from the base station.

[0499] At this time, low-quality reception information can be composed of a single UCI together with HARQ-ACK information and transmitted from the terminal to the base station.

[0500] In this case, when the terminal provides feedback of low-quality reception information to the base station, the low-quality reception information is included in the UCI for HARQ-ACK transmission and transmitted.

[0501] At this time, the payload size of the HARQ-ACK UCI is increased when the terminal performs feedback of low-quality received information compared to when it does not perform feedback of low-quality received information. This operation can be applied when the terminal's performance of feedback of low-quality received information is determined semi-statically, as in Method A-1 of Section 5.2 above.

[0502] Alternatively, the payload size of the HARQ-ACK UCI may be the same whether the terminal performs feedback on low-quality received information or performs feedback on low-quality received information. However, if feedback on low-quality received information is not performed, the state of notifying low-quality received information may not be used. This operation may be applied when the terminal's performance of feedback on low-quality received information is dynamically determined, as in Method A-2 of Section 5.2, or Approach B, or Approach C.

[0503] Alternatively, low-quality received information may be composed of a UCI independent of HARQ-ACK information and transmitted from the terminal to the base station.

[0504] In this case, when the terminal provides feedback of low-quality reception information to the base station, a UCI for HARQ-ACK transmission and a UCI containing the low-quality reception information are transmitted from the terminal to the base station.

[0505] In this case, the UCI containing low-quality reception information may be transmitted together or additionally when the terminal transmits the UCI containing HARQ-ACK information to the base station.

[0506] Specifically, if the terminal does not perform feedback of low-quality reception information, the UCI containing low-quality reception information is not transmitted, and only the UCI containing HARQ-ACK information is transmitted; however, if the terminal performs feedback of low-quality reception information, the UCI containing HARQ-ACK information and the UCI containing low-quality reception information may be transmitted together. This operation may be applied when the terminal's performance of feedback of low-quality reception information is determined semi-statically, as in Method A-1 of Section 5.2 above.

[0507] Alternatively, a UCI containing HARQ-ACK information and a UCI containing low-quality reception information may be transmitted together in both cases where the terminal does not perform feedback of low-quality reception information and where it performs feedback of low-quality reception information. However, in this case, the UCI containing low-quality reception information may not be used for actual feedback of low-quality reception information. In this case, the UCI containing low-quality reception information may be transmitted with specific values ​​(e.g., all zero values). This operation may be applied when the terminal's performance of feedback of low-quality reception information is dynamically determined, as in Method A-2 of Section 5.2, or Approach B, or Approach C.

[0508] In this case, the UCI containing low-quality reception information can be transmitted via the PUCCH / PUSCH resource, which transmits the UCI containing HARQ-ACK information to the base station.

[0509] <5.4. Method for Determining Low-Quality Reception>

[0510] A criterion for determining whether a terminal receives coded bits for a specific TB / CB / CBG from a base station and that the coded bits have poor reception quality that makes decoding difficult may be an implementation issue of the terminal, but may be defined in a standard for the stable implementation of the terminal.

[0511] For example, the terminal can determine whether the received coded bits are of low quality based on the following criteria.

[0512] The terminal measures the SINR and / or RSRQ at the resource that received the coded bits, and compares the measured SINR and / or RSRQ with a specific threshold; if the measured SINR and / or RSRQ is lower than the threshold, it can determine that it is a low-quality reception.

[0513] A resource that has received coded bits may mean a resource to which a TB, CB, or CBG containing coded bits has been transmitted.

[0514] The above threshold value may be a value defined in standard specifications. Alternatively, it may be a value that the terminal receives from the base station through RRC settings, etc.

[0515] If the terminal determines that the reception of specific coded bits is of low quality based on the above criteria, the terminal may provide feedback to the base station indicating that the coded bits were received of low quality.

[0516] If the terminal determines that the reception of coded bits to which a specific RV has been applied is of low quality based on the above criteria, the terminal may provide feedback to the base station indicating that retransmission of the RV is required.

[0517] FIG. 18 illustrates a method of operation of a terminal according to the present disclosure.

[0518] Referring to FIG. 18, the terminal receives downlink control information from a base station (S181). The downlink control information may include a redundancy version (RV) field. For example, the RV field may be composed of 2 bits.

[0519] The terminal receives data scheduled by the downlink control information from the base station (S182).

[0520] The terminal transmits HARQ-ACK (hybrid automatic repeat request-acknowledgement) information regarding the data to the base station, and when transmitting the HARQ-ACK information, the terminal transmits feedback information related to the RV index of the retransmitted data that requires retransmission among a plurality of RV (redundancy version) indices to the base station (S183).

[0521] When transmitting the above feedback information and HARQ-ACK information as UCI (uplink control information), the method for configuring UCI is described in detail in Section 5.3.

[0522] For example, the feedback information may include information indicating the RV index related to the retransmission data that requires retransmission.

[0523] Here, the data and the retransmission data may be a transport block, a code block, or a code block group (CBG).

[0524] The plurality of RV indices mentioned above may include, for example, RV0, RV1, RV2, and RV3. In this case, the data associated with RV0 may include all systematic bits and some parity bits to be received by the terminal. The data associated with RV1 or RV2 may include some parity bits but not the systematic bits to be received by the terminal. The data associated with RV3 may include some systematic bits and some parity bits to be received by the terminal.

[0525] According to an embodiment, the terminal may transmit the feedback information to the base station only when the data is related to RV0 among the plurality of RV indices. This has been described in detail in Approach B of Section 5.2.

[0526] According to an embodiment, the terminal may transmit the feedback information to the base station only when the HARQ-ACK information is a NACK among ACK (acknowledgement) and NACK (negative acknowledgement). This has been described in detail in Approach C of Section 5.2.

[0527] The terminal may generate the feedback information when the reception quality of the data is below a specific threshold. According to an embodiment, the terminal may generate the feedback information based on the Signal to Interference plus Noise Ratio (SINR) or Reference Signal Received Power (RSRP) at the resource that received the coded bits for the data. This has been described in detail in Section 5.4.

[0528] The terminal may further receive setting information from the base station that sets whether to transmit the feedback information. In this case, the terminal may transmit the feedback information to the base station only when the transmission of the feedback information is indicated by the setting information. This has been described in detail in Approach A of Section 5.2.

[0529] According to an embodiment, the feedback information may be included in the HARQ-ACK information. In this case, the HARQ-ACK information may indicate any one of the states indicated by the ACK, NACK, and the feedback information. This has been described in detail in Method B-1 and Method C-1 of Section 5.1.

[0530] According to the embodiment, the feedback information may be transmitted to the base station additionally / independently as separate information, without being included in the HARQ-ACK information. This has been described in detail in Method B-2 and Method C-2 of Section 5.1.

[0531] The above downlink control information is received via the PDCCH (physical downlink control channel), and the above data can be received via the PDSCH (physical downlink shared channel).

[0532] According to the method of the present disclosure, by having a terminal provide feedback information related to the RV index of retransmission data requiring retransmission to a base station, systomic bits essential for successful decoding can be received during retransmission. Thus, data transmission and reception performance is improved.

[0533] In addition, it can prevent delays that may occur due to the repeated retransmission of data that does not aid in decoding.

[0534] FIG. 19 illustrates the signaling process and operation between a base station and a terminal.

[0535] Referring to FIG. 19, the base station provides the terminal with configuration information related to the transmission of feedback information (S191). The base station can instruct the terminal to transmit the feedback information through the configuration information.

[0536] The base station transmits downlink control information to the terminal (S192).

[0537] The base station transmits data scheduled by the downlink control information to the terminal (S193).

[0538] After the terminal generates HARQ-ACK information and feedback information for the above data (S194), it transmits the HARQ-ACK information and feedback information to the base station (S195).

[0539] The above feedback information may include information related to the RV index of retransmitted data that requires retransmission among a plurality of RV (redundancy version) indices.

[0540] FIG. 20 illustrates a wireless device that can be applied to the present specification.

[0541] Referring to FIG. 20, the first wireless device (100) and the second wireless device (200) can transmit and receive wireless signals through various wireless access technologies (e.g., LTE, NR).

[0542] The first wireless device (100) includes at least one processor (102) and at least one memory (104), and may additionally include at least one transceiver (106) and / or at least one antenna (108). The at least one processor (102, hereinafter simply referred to as processor) controls at least one memory (104, hereinafter simply referred to as memory) and / or at least one transceiver (106, hereinafter simply referred to as transceiver or transceiver), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document. For example, the processor (102) may process information within the memory (104) to generate a first information / signal, and then transmit a wireless signal containing the first information / signal through the transceiver (106). Additionally, the processor (102) may receive a wireless signal containing a second information / signal through a transceiver (106) and then store information obtained from signal processing of the second information / signal in a memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may store software code containing instructions for performing some or all of the processes controlled by the processor (102) or for performing the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in this document. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (106) may be connected to the processor (102) and may transmit and / or receive a wireless signal through one or more antennas (108). The transceiver (106) may include a transmitter and / or a receiver. The transceiver (106) may be used in combination with an RF (Radio Frequency) unit.In this specification, a wireless device may refer to a communication modem / circuit / chip.

[0543] The processor (102) receives downlink control information from a base station, receives data scheduled by the downlink control information from the base station, and transmits HARQ-ACK (hybrid automatic repeat request-acknowledgement) information for the data to the base station, wherein when transmitting the HARQ-ACK information, it transmits feedback information related to the RV index of the retransmitted data that requires retransmission among a plurality of RV (redundancy version) indices to the base station. The specific operation has been described with reference to FIGS. 16 to 19.

[0544] The second wireless device (200) includes at least one processor (202) and at least one memory (204), and may additionally include at least one transceiver (206) and / or at least one antenna (208). The processor (202) controls the memory (204) and / or transceiver (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or sequences of operation disclosed herein. For example, the processor (202) may process information within the memory (204) to generate a third information / signal and then transmit a wireless signal containing the third information / signal through the transceiver (206). Additionally, the processor (202) may receive a wireless signal containing a fourth information / signal through the transceiver (206) and then store information obtained from the signal processing of the fourth information / signal in the memory (204). Memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, memory (204) may store software code containing instructions for performing some or all of the processes controlled by the processor (202) or for performing the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document. Here, the processor (202) and memory (204) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). A transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals through one or more antennas (208). The transceiver (206) may include a transmitter and / or receiver. The transceiver (206) may be interchangeable with an RF unit. In this specification, a wireless device may mean a communication modem / circuit / chip.

[0545] The processor (202) transmits downlink control information to a terminal, transmits data scheduled by the downlink control information to the terminal, and receives HARQ-ACK (hybrid automatic repeat request-acknowledgement) information regarding the data from the terminal, wherein upon receiving the HARQ-ACK information from the terminal, it receives feedback information related to the RV index of the retransmitted data that requires retransmission among a plurality of RV (redundancy version) indices. The specific operation has been described with reference to FIGS. 16 to 19.

[0546] Hereinafter, hardware elements of the wireless device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP, RRC, SDAP). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs) and / or Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document. One or more processors (102, 202) may generate a signal (e.g., baseband signal) containing a PDU, SDU, message, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in this document and provide it to one or more transceivers (106, 206). One or more processors (102, 202) may receive a signal (e.g., baseband signal) from one or more transceivers (106, 206) and may obtain a PDU, SDU, message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this document.

[0547] One or more processors (102, 202) may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). One or more processors (102, 202) may also be implemented as at least one computer-readable medium (CRM) containing instructions based on being executed by at least one processor.

[0548] For example, at least one computer-readable medium (CRM) comprising an instruction based on execution by at least one processor performs the steps of receiving downlink control information from a base station, receiving data scheduled by the downlink control information from the base station, and transmitting HARQ-ACK (hybrid automatic repeat request-acknowledgement) information for the data to the base station, wherein, when transmitting the HARQ-ACK information, feedback information related to the RV index of the retransmitted data requiring retransmission among a plurality of RV (redundancy version) indices is transmitted to the base station. The specific operation has been described with reference to FIGS. 16 to 19.

[0549] The descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be included in one or more processors (102, 202) or stored in one or more memories (104, 204) and driven by one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this document may be implemented using firmware or software in the form of code, instructions, and / or sets of instructions.

[0550] One or more memories (104, 204) may be connected to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories (104, 204) may be composed of ROM, RAM, EPROM, flash memory, hard drive, registers, cache memory, computer read storage media, and / or combinations thereof. One or more memories (104, 204) may be located inside and / or outside of one or more processors (102, 202). Additionally, one or more memories (104, 204) may be connected to one or more processors (102, 202) through various technologies such as wired or wireless connections.

[0551] One or more transceivers (106, 206) may transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or operation flowcharts, etc., of this document to one or more other devices. One or more transceivers (106, 206) may receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or operation flowcharts, etc., disclosed in this document from one or more other devices. For example, one or more transceivers (106, 206) may be connected to one or more processors (102, 202) and may transmit and receive wireless signals. For example, one or more processors (102, 202) may control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be connected to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this document through one or more antennas (108, 208). In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can convert the received wireless signal / channel, etc. from an RF band signal to a baseband signal in order to process the received user data, control information, wireless signal / channel, etc. using one or more processors (102, 202).One or more transceivers (106, 206) can convert user data, control information, wireless signals / channels, etc. processed using one or more processors (102, 202) from baseband signals to RF band signals. To this end, one or more transceivers (106, 206) may include (analog) oscillators and / or filters.

[0552] Figure 21 illustrates another example of a wireless device.

[0553] According to FIG. 21, the wireless device may include at least one processor (102, 202), at least one memory (104, 204), at least one transceiver (106, 206), and one or more antennas (108, 208).

[0554] The difference between the example of the wireless device described in FIG. 20 and the example of the wireless device in FIG. 21 is that in FIG. 20, the processor (102, 202) and the memory (104, 204) are separated, whereas in the example of FIG. 21, the memory (104, 204) is included in the processor (102, 202). For example, the processor and the memory may form a single chipset.

[0555] FIG. 22 illustrates an example of a signal processing module structure. Here, signal processing may be performed in the processor (102, 202) of FIG. 20.

[0556] Referring to FIG. 22, a transmission device (e.g., a processor, a processor and memory, or a processor and a transceiver) within a terminal or base station may include a scrambler (301), a modulator (302), a layer mapper (303), an antenna port mapper (304), a resource block mapper (305), and a signal generator (306).

[0557] The transmission device can transmit one or more codewords. Each coded bit within a codeword is scrambled by a scrambler (301) and transmitted over a physical channel. A codeword may be referred to as a data sequence and may be equivalent to a transmission block, which is a data block provided by the MAC layer.

[0558] The scrambled bits are modulated into complex-valued modulation symbols by a modulator (302). The modulator (302) can modulate the scrambled bits according to a modulation scheme to arrange them into complex-valued modulation symbols representing positions on a signal constellation. There are no restrictions on the modulation scheme, and m-PSK (m-Phase Shift Keying) or m-QAM (m-Quadrature Amplitude Modulation), etc., may be used for modulating the encoded data. The modulator may be referred to as a modulation mapper.

[0559] The complex modulation symbols above can be mapped to one or more transmission layers by a layer mapper (303). The complex modulation symbols on each layer can be mapped by an antenna port mapper (304) for transmission on an antenna port.

[0560] The resource block mapper (305) can map complex modulation symbols for each antenna port to appropriate resource elements within a virtual resource block allocated for transmission. The resource block mapper can map the virtual resource block to a physical resource block according to an appropriate mapping scheme. The resource block mapper (305) can assign complex modulation symbols for each antenna port to appropriate subcarriers and multiplex them according to the user.

[0561] The signal generator (306) can generate a complex-valued time domain OFDM symbol signal by modulating a complex modulation symbol for each antenna port, for example, an antenna-specific symbol, using a specific modulation method, for example, OFDM (Orthogonal Frequency Division Multiplexing). The signal generator can perform an Inverse Fast Fourier Transform (IFFT) on the antenna-specific symbol, and a Cyclic Prefix (CP) can be inserted into the time domain symbol after the IFFT is performed. The OFDM symbol is transmitted to a receiving device through each transmitting antenna after undergoing digital-to-analog conversion, frequency uplink conversion, etc. The signal generator may include an IFFT module, a CP inserter, a Digital-to-Analog Converter (DAC), a frequency uplink converter, etc.

[0562] FIG. 23 illustrates another example of a signal processing module structure within a transmission device. Here, signal processing can be performed in a processor of a terminal / base station, such as the processor (102, 202) of FIG. 20.

[0563] Referring to FIG. 23, a transmission device (e.g., a processor, a processor and memory, or a processor and a transceiver) within a terminal or base station may include a scrambler (401), a modulator (402), a layer mapper (403), a precoder (404), a resource block mapper (405), and a signal generator (406).

[0564] For one codeword, the transmission device can scramble the coded bits within the codeword by the scrambler (401) and then transmit them through the physical channel.

[0565] The scrambled bits are modulated into complex modulation symbols by a modulator (402). The modulator may modulate the scrambled bits according to a predetermined modulation scheme to arrange them into complex modulation symbols representing positions on a signal constellation. There are no restrictions on the modulation scheme, and pi / 2-BPSK (pi / 2-Binary Phase Shift Keying), m-PSK (m-Phase Shift Keying), or m-QAM (m-Quadrature Amplitude Modulation), etc., may be used for modulating the encoded data.

[0566] The complex modulation symbol can be mapped to one or more transmission layers by the layer mapper (403).

[0567] Complex modulation symbols on each layer can be precoded by a precoder (404) for transmission on an antenna port. Here, the precoder may perform precoding after performing transform precoding on the complex modulation symbols. Alternatively, the precoder may perform precoding without performing transform precoding. The precoder (404) may process the complex modulation symbols in a MIMO manner according to multiple transmission antennas to output antenna-specific symbols and distribute the antenna-specific symbols to the corresponding resource block mapper (405). The output z of the precoder (404) can be obtained by multiplying the output y of the layer mapper (403) by an N-X-M precoding matrix W. Here, N is the number of antenna ports and M is the number of layers.

[0568] The resource block mapper (405) maps the demodulation modulation symbol for each antenna port to the appropriate resource element within the virtual resource block allocated for transmission.

[0569] The resource block mapper (405) can assign complex modulation symbols to appropriate subcarriers and multiplex them according to the user.

[0570] The signal generator (406) can generate a complex-valued time domain Orthogonal Frequency Division Multiplexing (OFDM) symbol signal by modulating a complex modulated symbol using a specific modulation method, such as OFDM. The signal generator (406) can perform an Inverse Fast Fourier Transform (IFFT) on an antenna-specific symbol, and a Cyclic Prefix (CP) can be inserted into the time domain symbol after the IFFT is performed. The OFDM symbol is transmitted to a receiving device through each transmitting antenna after undergoing digital-to-analog conversion, frequency uplink conversion, etc. The signal generator (406) may include an IFFT module, a CP inserter, a Digital-to-Analog Converter (DAC), a frequency uplink converter, etc.

[0571] The signal processing process of the receiving device may be configured as the inverse of the signal processing process of the transmitter. Specifically, the processor of the receiving device performs decoding and demodulation for a wireless signal received from the outside through the antenna port(s) of the transmitter and receiver. The receiving device may include multiple receiving antennas, and each signal received through the receiving antennas is restored to a baseband signal, then undergoes multiplexing and MIMO demodulation to be restored to the data sequence that the transmitting device originally intended to transmit. The receiving device (1820) may include a signal restorer for restoring the received signal to a baseband signal, a multiplexer for combining and multiplexing the received processed signals, and a channel demodulator for demodulating the multiplexed signal sequence into the corresponding codeword. The signal restorer, multiplexer, and channel demodulator may be configured as a single integrated module or as separate independent modules that perform their functions. More specifically, the signal restorer may include an analog-to-digital converter (ADC) that converts an analog signal into a digital signal, a CP remover that removes CP from the digital signal, an FFT module that applies a fast Fourier transform (FFT) to the signal from which CP has been removed to output a frequency domain symbol, and a resource element demapper / equalizer that restores the frequency domain symbol to an antenna-specific symbol. The antenna-specific symbol is restored to a transport layer by a multiplexer, and the transport layer is restored to a codeword that the transmitting device intended to transmit by a channel demodulator.

[0572] FIG. 24 illustrates an example of a wireless communication device according to an embodiment of the present disclosure.

[0573] Referring to FIG. 24, a wireless communication device, for example, a terminal, may include at least one of a processor (2310), such as a digital signal processor (DSP) or a microprocessor, a transceiver (2335, transceiver), a power management module (2305), an antenna (2340), a battery (2355), a display (2315), a keypad (2320), a Global Positioning System (GPS) chip (2360), a sensor (2365), a memory (2330), a Subscriber Identification Module (SIM) card (2325), a speaker (2345), and a microphone (2350). The antenna and the processor may be multiple.

[0574] The processor (2310) can implement the functions, procedures, and methods described in this specification. The processor (2310) of FIG. 24 may be the processor (102, 202) of FIG. 20.

[0575] The memory (2330) is connected to the processor (2310) and stores information related to the operation of the processor. The memory may be located inside or outside the processor and may be connected to the processor through various technologies such as wired or wireless connections. The memory (2330) of FIG. 24 may be the memory (104, 204) of FIG. 20.

[0576] The user can input various types of information, such as phone numbers, using various techniques, such as pressing a button on the keypad (2320) or using a microphone (2350) to activate sound. The processor (2310) receives and processes the user's information and can perform appropriate functions, such as making a call to the input phone number. In some scenarios, data may be retrieved from a SIM card (2325) or memory (2330) to perform appropriate functions. In some scenarios, the processor (2310) can display various types of information and data on a display (2315) for the user's convenience.

[0577] A transceiver (2335) is connected to a processor (2310) to transmit and / or receive a wireless signal, such as a Radio Frequency (RF) signal. The processor may control the transceiver to initiate communication or to transmit a wireless signal containing various types of information or data, such as voice communication data. The transceiver includes a transmitter and a receiver for transmitting and receiving wireless signals. An antenna (2340) may facilitate the transmission and reception of wireless signals. In some embodiments, when the transceiver receives a wireless signal, it may forward and convert the signal to a baseband frequency for processing by the processor. The processed signal may be processed by various techniques, such as being converted into audible or readable information to be output through a speaker (2345). The transceiver of FIG. 24 may be the transceiver (106, 206) of FIG. 20.

[0578] Although not illustrated in FIG. 24, various components such as a camera and a USB (Universal Serial Bus) port may be additionally included in the terminal. For example, the camera may be connected to the processor (2310).

[0579] FIG. 24 is merely one example of an implementation of a terminal, and is not limited thereto. The terminal is not required to include all the elements of FIG. 24. For example, some components, such as a keypad (2320), a Global Positioning System (GPS) chip (2360), a sensor (2365), and a SIM card (2325), may not be essential and, in this case, may not be included in the terminal.

[0580] FIG. 25 illustrates a communication system (1) applicable to the present specification.

[0581] Referring to FIG. 25, the communication system (1) to which the present specification applies includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using wireless access technology (e.g., 5G NR (New RAT), LTE (Long Term Evolution)) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (eXtended Reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Thing) device (100f), and an AI device / server (400). For example, the vehicle may include a vehicle equipped with wireless communication capabilities, an autonomous vehicle, a vehicle capable of performing inter-vehicle communication, etc. Here, the vehicle may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). XR devices include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices and can be implemented in the form of HMDs (Head-Mounted Devices), HUDs (Head-Up Displays) equipped in vehicles, televisions, smartphones, computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. Portable devices may include smartphones, smartpads, wearable devices (e.g., smartwatches, smart glasses), computers (e.g., laptops, etc.). Home appliances may include TVs, refrigerators, washing machines, etc. IoT devices may include sensors, smart meters, etc. For example, base stations and networks may be implemented as wireless devices, and a specific wireless device (200a) may operate as a base station / network node to other wireless devices.

[0582] Wireless devices (100a to 100f) can be connected to a network (300) through a base station (200). Artificial Intelligence (AI) technology may be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (400) through the network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. The wireless devices (100a to 100f) may communicate with each other through the base station (200) / network (300), but they may also communicate directly (e.g., sidelink communication) without going through the base station / network. For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (Vehicle to Vehicle) / V2X (Vehicle to everything) communication). Also, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0583] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a~100f) / base station (200) and base station (200) / base station (200). Here, wireless communication / connection can be achieved through various wireless access technologies (e.g., 5G NR), such as uplink / downlink communication (150a), sidelink communication (150b) (or D2D communication), and inter-base station communication (150c) (e.g., relay, IAB (Integrated Access Backhaul)). Through wireless communication / connection (150a, 150b, 150c), wireless devices and base stations / wireless devices, and base stations and base stations can transmit / receive wireless signals to / from each other. For example, wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, based on various proposals of this specification, at least some of the following may be performed: various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), resource allocation processes, etc.

[0584] Meanwhile, NR supports multiple numerologies (or subcarrier spacing (SCS)) to support various 5G services. For example, when the SCS is 15 kHz, it supports a wide area in traditional cellular bands; when the SCS is 30 kHz / 60 kHz, it supports dense-urban, lower latency, and wider carrier bandwidth; and when the SCS is 60 kHz or higher, it supports a bandwidth greater than 24.25 GHz to overcome phase noise.

[0585] The NR frequency band can be defined by two types of frequency ranges (FR1, FR2). The numerical values ​​of the frequency ranges may change, for example, the two types of frequency ranges (FR1, FR2) may be as shown in Table 11 below. For convenience of explanation, among the frequency ranges used in the NR system, FR1 may mean "sub 6GHz range" and FR2 may mean "above 6GHz range" and may be referred to as millimeter wave (mmW).

[0586] [Table 11]

[0587]

[0588] As described above, the numerical values ​​of the frequency range of the NR system may change. For example, FR1 may include a band of 410 MHz to 7125 MHz as shown in Table 12 below. For example, FR1 may include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher. For example, the frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher included within FR1 may include an unlicensed band. The unlicensed band may be used for various purposes, for example, for communication for vehicles (e.g., autonomous driving).

[0589] [Table 12]

[0590]

[0591] The claims described in this specification may be combined in various ways. For example, the technical features of the method claims in this specification may be combined to be implemented as a device, and the technical features of the device claims in this specification may be combined to be implemented as a method. Furthermore, the technical features of the method claims and the technical features of the device claims in this specification may be combined to be implemented as a device, and the technical features of the method claims and the technical features of the device claims in this specification may be combined to be implemented as a method.

Claims

1. Regarding the method, The terminal receives downlink control information from the base station, and The above terminal receives data scheduled from the base station based on the downlink control information, and The above terminal transmits HARQ-ACK (hybrid automatic repeat request-acknowledgement) information regarding the above data to the base station, A method characterized in that, when the above terminal transmits the above HARQ-ACK information, it transmits feedback information related to the RV index of the retransmitted data requiring retransmission among a plurality of RV (redundancy version) indices to the base station.

2. A method according to claim 1, characterized in that the feedback information includes information indicating the RV index.

3. A method according to claim 1, wherein the data and the retransmission data are a transport block, a code block, or a code block group (CBG).

4. A method according to claim 1, characterized in that the plurality of RV indices include RV0, RV1, RV2, and RV3.

5. A method according to claim 4, wherein the data associated with the RV0 includes all systematic bits and some parity bits to be received by the terminal.

6. A method according to claim 4, wherein the data associated with the RV1 or the RV2 includes some parity bits and does not include systomic bits to be received by the terminal.

7. A method according to claim 4, wherein the data related to the RV3 includes some systematic bits and some parity bits to be received by the terminal.

8. A method according to claim 1, characterized by generating feedback information based on SINR (Signal to Interference plus Noise Ratio) or RSRP (Reference Signal Received Power) at a resource that received the coded bits for the data.

9. A method according to claim 1, characterized in that the feedback information is transmitted to the base station only when the data is related to RV0 among the plurality of RV indices.

10. A method according to claim 1, characterized in that the feedback information is transmitted to the base station only when the HARQ-ACK information is NACK among ACK (acknowledgement) and NACK (negative acknowledgement).

11. A method according to claim 1, characterized by generating feedback information when the reception quality of the data is below a specific threshold.

12. A method according to claim 1, characterized in that the terminal receives setting information for setting whether to transmit the feedback information.

13. A method according to claim 12, characterized in that the terminal transmits the feedback information to the base station only when the transmission of the feedback information is instructed by the setting information.

14. A method according to claim 1, wherein, when the feedback information is included in the HARQ-ACK information, the HARQ-ACK information indicates any one of the states indicated by ACK, NACK, and the state indicated by the feedback information.

15. A method according to claim 1, characterized in that the feedback information is not included in the HARQ-ACK information and is transmitted to the base station as separate information.

16. A method according to claim 1, characterized in that the downlink control information is received via a PDCCH (physical downlink control channel) and the data is received via a PDSCH (physical downlink shared channel).

17. The terminal, At least one transceiver; At least one memory; and The above includes at least one memory and at least one processor operably coupled with the above at least one transceiver, The above at least one memory includes instructions that are executed by the above at least one processor to perform operations, wherein The above operations are, Receive downlink control information from the base station, and Receive data scheduled by the downlink control information from the base station, and Transmit HARQ-ACK (hybrid automatic repeat request-acknowledgement) information regarding the data to the base station, A terminal characterized by transmitting feedback information related to the RV index of retransmission data requiring retransmission among a plurality of RV (redundancy version) indices to the base station when transmitting the HARQ-ACK information.

18. A terminal according to claim 17, characterized in that the feedback information includes information indicating the RV index.

19. A terminal according to claim 17, wherein the data and the retransmission data are a transport block, a code block, or a code block group (CBG).

20. A terminal according to claim 17, characterized in that the plurality of RV indices include RV0, RV1, RV2, and RV3.

21. A terminal according to claim 20, wherein the data associated with the RV0 comprises all systematic bits and some parity bits to be received by the terminal.

22. A terminal according to claim 20, wherein the data associated with the RV1 or the RV2 includes some parity bits and does not include systomic bits to be received by the terminal.

23. A terminal according to claim 20, wherein the data related to the RV3 includes some systematic bits and some parity bits to be received by the terminal.

24. A terminal according to claim 17, characterized by generating feedback information based on SINR (Signal to Interference plus Noise Ratio) or RSRP (Reference Signal Received Power) at a resource that received the coded bits for the data.

25. A terminal according to claim 17, characterized in that it transmits feedback information to the base station only when the data is related to RV0 among the plurality of RV indices.

26. A terminal according to claim 17, characterized in that it transmits feedback information to the base station only when the HARQ-ACK information is NACK among ACK (acknowledgement) and NACK (negative acknowledgement).

27. A terminal according to claim 17, characterized by generating feedback information when the reception quality of the data is below a specific threshold.

28. A terminal according to claim 17, characterized in that the terminal receives setting information for setting whether to transmit the feedback information.

29. A terminal according to claim 28, characterized in that the terminal transmits the feedback information to the base station only when the transmission of the feedback information is instructed by the setting information.

30. A terminal according to claim 17, wherein, when the feedback information is included in the HARQ-ACK information, the HARQ-ACK information indicates any one of the states indicated by ACK, NACK, and the state indicated by the feedback information.

31. A terminal according to claim 17, characterized in that the feedback information is not included in the HARQ-ACK information and is transmitted to the base station as separate information.

32. A terminal according to claim 17, characterized in that the downlink control information is received via a PDCCH (physical downlink control channel) and the data is received via a PDSCH (physical downlink shared channel).

33. The device is, At least one memory; and The above includes at least one processor operably coupled with at least one memory, The above at least one memory includes instructions that are executed by the above at least one processor to perform operations, wherein The above operations are, Receive downlink control information from the base station, and Receive data scheduled by the downlink control information from the base station, and Transmit HARQ-ACK (hybrid automatic repeat request-acknowledgement) information regarding the data to the base station, A device characterized by the above terminal transmitting feedback information related to the RV index of retransmission data requiring retransmission among a plurality of RV (redundancy version) indices to the base station when transmitting the above HARQ-ACK information.

34. At least one computer-readable medium (CRM) comprising instructions based on execution by at least one processor, Step of receiving downlink control information from a base station, A step of receiving data scheduled by the downlink control information from the base station, and Performing the step of transmitting HARQ-ACK (hybrid automatic repeat request-acknowledgement) information regarding the above data to the base station, A CRM characterized by transmitting feedback information related to the RV index of retransmission data requiring retransmission among a plurality of RV (redundancy version) indices to the base station when transmitting the above HARQ-ACK information.

35. Regarding the method, The base station transmits downlink control information to the terminal, and The base station transmits data scheduled by the downlink control information to the terminal, and The base station receives HARQ-ACK (hybrid automatic repeat request-acknowledgement) information regarding the data from the terminal, A method characterized in that, upon receiving HARQ-ACK information from the terminal, the base station receives feedback information related to the RV index of the retransmitted data requiring retransmission among a plurality of RV (redundancy version) indices.

36. A base station is, At least one transceiver; At least one memory; and The above includes at least one memory and at least one processor operably coupled with the above at least one transceiver, The above at least one memory includes instructions that are executed by the above at least one processor to perform operations, wherein The above operations are, Transmit downlink control information to the terminal, and Transmitting data scheduled by the downlink control information to the above terminal, and It includes receiving HARQ-ACK (hybrid automatic repeat request-acknowledgement) information regarding the data from the terminal, A base station characterized by receiving feedback information related to the RV index of a retransmission data requiring retransmission among a plurality of RV (redundancy version) indices when receiving HARQ-ACK information from the terminal.

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