Method and device for hybrid automatic repeat request feedback in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate than a 4G communication system such as LTE. A method performed by a user equipment (UE) in a wireless communication system according to an embodiment of the present disclosure may comprise the steps of: receiving downlink control information (DCI) from a base station through a physical downlink control channel (PDCCH); decoding data received from the base station through a physical downlink shared channel (PDSCH) on the basis of the DCI; generating information necessary for interference control or link adaptation of the base station on the basis of the result of decoding the data received through the PDSCH; and transmitting, to the base station, the information necessary for interference control or link adaptation of the base station together with a hybrid automatic repeat request (HARQ) feedback indicating whether the decoding of the data is successful.

Description

Method and device for hybrid automatic retransmission request feedback in a wireless communication system

[0001] The present disclosure relates to a method for HARQ (hybrid automatic repeat request) feedback in a wireless communication system.

[0002] Looking back at the evolution of wireless communication through successive generations, technologies have been developed primarily for human-oriented services, such as voice, multimedia, and data. Following the commercialization of 5G (5th-generation) communication systems, connected devices, which have been increasing explosively, are expected to be connected to communication networks. Examples of networked objects include vehicles, robots, drones, home appliances, displays, smart sensors installed in various infrastructures, construction machinery, and factory equipment. Mobile devices are expected to evolve into various form factors, such as augmented reality glasses, virtual reality headsets, and holographic devices. In the 6G (6th-generation) era, efforts are underway to develop improved 6G communication systems to connect hundreds of billions of devices and objects to provide diverse services. For this reason, 6G communication systems are being referred to as "beyond 5G" systems.

[0003] In the 6G communication system predicted to be realized around 2030, the maximum transmission speed is tera (i.e., 1,000 gigabit) bps, and the wireless latency is 100 microseconds (μsec). In other words, compared to the 5G communication system, the transmission speed in the 6G communication system is 50 times faster, and the wireless latency is reduced to one-tenth.

[0004] To achieve such high data transmission speeds and ultra-low latency, 6G communication systems are being considered for implementation in the terahertz band (e.g., the 95 GHz to 3 terahertz (3 THz) band). In the terahertz band, due to more severe path loss and atmospheric absorption compared to the millimeter wave (mmWave) band introduced in 5G, the importance of technology capable of guaranteeing signal reach, or coverage, is expected to increase. As key technologies to ensure coverage, radio frequency (RF) devices, antennas, new waveforms that offer better coverage than orthogonal frequency division multiplexing (OFDM), beamforming, and multi-antenna transmission technologies such as massive multiple-input and multiple-output (massive MIMO), full-dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas must be developed. In addition, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing technology using orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS) are being discussed to improve coverage of terahertz band signals.

[0005] In addition, to improve frequency efficiency and system network, development is underway in 6G communication systems for full duplex technology, in which uplink and downlink simultaneously utilize the same frequency resources at the same time; network technology that integrates satellites and HAPS (high-altitude platform stations); network structure innovation technology that supports mobile base stations and enables network operation optimization and automation; dynamic spectrum sharing technology through collision avoidance based on spectrum usage prediction; AI-based communication technology that utilizes AI (artificial intelligence) from the design stage and internalizes end-to-end AI support functions to realize system optimization; and next-generation distributed computing technology that realizes services of complexity exceeding the limits of terminal computing capabilities by utilizing ultra-high performance communication and computing resources (mobile edge computing (MEC), cloud, etc.). In addition, attempts are continuing to further strengthen connectivity between devices, further optimize networks, promote the softwareization of network entities, and increase the openness of wireless communication through the design of new protocols to be used in 6G communication systems, the implementation of hardware-based security environments, the development of mechanisms for the safe utilization of data, and the development of technologies regarding privacy maintenance methods.

[0006] Due to the research and development of such 6G communication systems, it is expected that a new dimension of hyper-connected experience will become possible through the hyper-connectivity of 6G communication systems, which encompasses not only connections between objects but also connections between people and objects. Specifically, it is projected that 6G communication systems will enable the provision of services such as truly immersive extended reality (truly immersive XR), high-fidelity mobile holograms, and digital replicas. Furthermore, services such as remote surgery, industrial automation, and emergency response, which are provided through 6G communication systems with enhanced security and reliability, will be applied in various fields including industry, healthcare, automotive, and home appliances.

[0007] Meanwhile, in wireless communication systems such as LTE and 5G, HARQ (hybrid automatic repeat request) feedback, which combines error correction and retransmission techniques, is being used to ensure the reliability of data transmission.

[0008] The present disclosure provides a HARQ feedback method for improving interference control and link adaptation technology.

[0009] A method of a user equipment (UE) in a wireless communication system according to one embodiment of the present disclosure may include: receiving downlink control information (DCI) from a base station via a physical downlink control channel (PDCCH); decoding data received from the base station via a physical downlink shared channel (PDSCH) based on the DCI; generating information necessary for interference control or link adaptation of the base station based on the decoding result of the data received via the PDSCH; and transmitting the information necessary for interference control or link adaptation of the base station to the base station, along with a hybrid automatic repeat request (HARQ) feedback indicating whether the decoding of the data was successful.

[0010] A method of a base station according to one embodiment of the present disclosure may include: transmitting downlink control information (DCI) to user equipment (UE) via a physical downlink control channel (PDCCH); transmitting data to the UE via a physical downlink shared channel (PDSCH); and receiving information required for interference control or link adaptation of the base station from the UE, along with hybrid automatic repeat request (HARQ) feedback indicating whether decoding of the data was successful. The information required for interference control or link adaptation of the base station may be generated based on the decoding result of the data.

[0011] In a wireless communication system according to one embodiment of the present disclosure, the UE (user equipment) includes a transceiver; and a control unit. The control unit can: receive downlink control information (DCI) from a base station via a physical downlink control channel (PDCCH); decode data received from the base station via a physical downlink shared channel (PDSCH) based on the DCI; generate information necessary for interference control or link adaptation of the base station based on the decoding result of the data received via the PDSCH; and control the transmission of information necessary for interference control or link adaptation of the base station to the base station, along with HARQ (hybrid automatic repeat request) feedback indicating whether the decoding of the data was successful.

[0012] In a wireless communication system according to one embodiment of the present disclosure, a base station comprises: a transceiver; and a control unit. The control unit controls the transmission of downlink control information (DCI) to user equipment (UE) via a physical downlink control channel (PDCCH), controls the transmission of data to the UE via a physical downlink shared channel (PDSCH), and can receive information necessary for interference control or link adaptation of the base station from the UE, along with HARQ (hybrid automatic repeat request) feedback indicating whether decoding of the data was successful. The information necessary for interference control or link adaptation of the base station may be generated based on the decoding result of the data.

[0013] The method and apparatus according to the embodiments of the present disclosure can select an appropriate Modulation and Coding Scheme (MCS) using a HARQ feedback method for interference control and link adaptation technology improvement.

[0014] In addition, the method and apparatus according to the embodiments of the present disclosure can reduce latency by reducing the number of HARQ process iterations using a HARQ feedback method for interference control and link adaptation technology improvement, and improve system throughput through interference control.

[0015] FIG. 1 is a drawing illustrating the structure of a wireless communication system according to an embodiment of the present disclosure.

[0016] FIG. 2 is a diagram showing a wireless protocol structure in an LTE system according to an embodiment of the present disclosure.

[0017] FIG. 3 is a diagram showing the wireless protocol structure of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0018] Figures 4a and 4b are examples to illustrate interference situations that vary depending on the resource allocation of interference signals.

[0019] Figures 5a and 5b are diagrams illustrating a method for estimating the state of a UE channel using link application technology.

[0020] FIG. 6 is a flowchart illustrating an MCS indicator reporting method for link adaptation (LA) according to one embodiment of the present disclosure.

[0021] FIGS. 7a and 7b are drawings illustrating the change in the estimated SINR value of the link application (LA) operation during feedback according to one embodiment of the present disclosure.

[0022] FIG. 8 is a flowchart for explaining a method for reporting the number of required retransmissions of a terminal according to one embodiment of the present disclosure.

[0023] Figure 9a shows an example of a conventional retransmission operation of a base station based on Nack feedback from a terminal.

[0024] FIG. 9b illustrates an example of a base station's retransmission operation in response to Nack feedback of a terminal according to an embodiment of the present disclosure.

[0025] FIG. 9c shows another example of a base station's retransmission operation in response to Nack feedback of a terminal according to an embodiment of the present disclosure.

[0026] FIG. 10 illustrates an example of a pre-configured method between a base station and a terminal for reporting MCS difference or retransmission counts according to one embodiment of the present disclosure.

[0027] FIG. 11 illustrates another example of a preset method between a base station and a terminal for reporting MCS difference or retransmission counts according to one embodiment of the present disclosure.

[0028] FIG. 12 illustrates another example of a preset method between a base station and a terminal for reporting MCS difference or retransmission counts according to one embodiment of the present disclosure.

[0029] FIG. 13 is a flowchart illustrating a method for reporting interference or electric field weakening of a terminal according to one embodiment of the present disclosure.

[0030] FIG. 14 illustrates an example of a pre-configuration method between a base station and a terminal for reporting interference or electric field weakening according to one embodiment of the present disclosure.

[0031] FIG. 15 illustrates another example of a pre-configured method between a base station and a terminal for reporting interference or electric field weakening according to one embodiment of the present disclosure.

[0032] FIG. 16 illustrates another example of a pre-configured method between a base station and a terminal for reporting interference or electric field weakening according to one embodiment of the present disclosure.

[0033] FIG. 17 is a flowchart illustrating a method for reporting interference types of a terminal according to one embodiment of the present disclosure.

[0034] FIG. 18 illustrates an example of a preset method between a base station and a terminal for interference type reporting according to one embodiment of the present disclosure.

[0035] FIG. 19 illustrates another example of a preset method between a base station and a terminal for interference type reporting according to one embodiment of the present disclosure.

[0036] FIG. 20 illustrates another example of a preset method between a base station and a terminal for interference type reporting according to one embodiment of the present disclosure.

[0037] FIG. 21 is a block diagram illustrating a terminal according to embodiments of the present disclosure.

[0038] FIG. 22 is a block diagram illustrating a base station according to embodiments of the present disclosure.

[0039] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that identical components in the accompanying drawings are represented by the same reference numerals whenever possible. Furthermore, detailed descriptions of known functions and configurations that may obscure the essence of the present disclosure will be omitted.

[0040] In describing the embodiments in this specification, descriptions of technical details that are well known in the technical field to which this disclosure belongs and are not directly related to this disclosure are omitted. This is intended to convey the essence of this disclosure more clearly without obscuring it by omitting unnecessary explanations.

[0041] For the same reason, some components in the attached drawings have been exaggerated, omitted, or schematically depicted. Additionally, the size of each component does not entirely reflect its actual dimensions. Identical or corresponding components in each drawing have been assigned the same reference numbers.

[0042] The advantages and features of the present disclosure and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below but may be implemented in various different forms. The embodiments provided are merely to ensure that the disclosure of the present disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0043] At this time, it will be understood that each block of the process flow diagrams and combinations of the flow diagrams can be executed by computer program instructions. Since these computer program instructions can be loaded into the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, the instructions executed through the processor of the computer or other programmable data processing equipment create means to perform the functions described in the flow diagram block(s). Since these computer program instructions can also be stored in computer-available or computer-readable memory that can be directed toward the computer or other programmable data processing equipment to implement the function in a specific way, the instructions stored in computer-available or computer-readable memory can also produce a manufactured item containing the means of instruction to perform the function described in the flow diagram block(s). Since computer program instructions can be loaded onto a computer or other programmable data processing equipment, instructions that perform a series of operation steps on the computer or other programmable data processing equipment to create a process executed by the computer can also provide steps for executing the functions described in the flowchart block(s).

[0044] Additionally, each block may represent a module, segment, or part of code containing one or more executable instructions for executing a specified logical function(s). It should also be noted that in some alternative execution examples, the functions mentioned in the blocks may occur out of order. For instance, two blocks described in succession may actually be executed substantially simultaneously, or the blocks may be executed in reverse order according to their corresponding functions.

[0045] In this embodiment, the term "part" refers to a software or hardware component such as an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit), and the "part" performs certain roles. However, the meaning of "part" is not limited to software or hardware. The "part" may be configured to reside in an addressable storage medium or configured to run one or more processors. Accordingly, as an example, the "part" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and "parts" may be combined into a smaller number of components and "parts" or further separated into additional components and "parts." In addition, the components and '~parts' may be implemented to play one or more CPUs within the device or secure multimedia card.

[0046] In embodiments of the present disclosure, the base station is an entity that performs resource allocation for terminals and may be at least one of a gNode B, gNB, eNode B, eNB, Node B, BS, radio access unit, base station controller, or a node on a network. Additionally, the base station may be a network entity comprising at least one of an IAB-donor (Integrated Access and Backhaul donor) which is a gNB providing network access to terminal(s) through a network of backhaul and access links in an NR system, and an IAB-node which is a RAN (radio access network) node that supports NR access link(s) to terminal(s) and supports NR backhaul links to said IAB-donor or another IAB-node. A terminal may be radio-connected through an IAB-node and may transmit and receive data with an IAB-donor connected to at least one IAB-node through a backhaul link.

[0047] In addition, the above terminal may include user equipment (UE), a mobile station (MS), a cellular phone, a smartphone, a computer, or various devices capable of performing communication functions. In this disclosure, the downlink (DL) refers to the wireless transmission path of a signal transmitted by a base station to a terminal, and the uplink (UL) refers to the wireless transmission path of a signal transmitted by a terminal to a base station. Furthermore, while LTE or LTE-A systems may be described below as examples, embodiments of this disclosure may also be applied to other communication systems having similar technical backgrounds or channel types. For example, 5th generation mobile communication technologies (5G, new radio, NR) or 6G developed after LTE-A may be included therein, and the 5G or 6G below may be a concept that includes existing LTE, LTE-A, and other similar services. Additionally, this disclosure may be applied to other communication systems with some modifications made at the discretion of a person with skilled technical knowledge, provided that it does not deviate significantly from the scope of this disclosure.

[0048] Terms used in the following description to refer to signals, channels, control information, network entities, and device components are examples provided for the convenience of explanation. Additionally, terms used in the following description to refer to nodes, messages, interfaces between network entities, and various information are examples provided for the convenience of explanation. Accordingly, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

[0049] Additionally, the present disclosure describes various embodiments using terms used in some communication standards (e.g., 3GPP (3rd Generation Partnership Project)), but this is merely illustrative. Various embodiments of the present disclosure can be easily modified and applied to other communication systems.

[0050] FIG. 1 is a drawing illustrating the structure of a wireless communication system according to an embodiment of the present disclosure.

[0051] FIG. 1 illustrates an example in which a plurality of base stations and terminals (UE: user equipment) move and change the connected base station in a mobile communication system to which embodiments of the present disclosure are applied.

[0052] Base stations (1-20, 1-30) can be connected to some surrounding base stations, and base stations (1-20, 1-30) can be connected to a mobile communication core network (CN: Core Network) (1-40) such as an EPC (Evolved Packet Core), a 5GC (5G Core Network), or a 6G network.

[0053] The radio access technology of the base stations (1-20, 1-30) may be LTE, NR, Wi-Fi, 6G, etc., and is not limited to one example. For example, the base stations (1-20, 1-30) may be mobile communication base stations unrelated to the radio access technology.

[0054] A terminal (1-10) can be connected to a base station to receive mobile communication services, and as the terminal (1-10) moves, the connected base station may change, and the terminal (1-10) can receive mobile communication services without interruption through a handover (HO: Handover, or handoff) procedure. In one example of FIG. 1, the terminal (1-10) is connected to a base station (1-20), and then disconnects from the base station (1-20) through a handover and connects to a new base station (1-30).

[0055] FIG. 2 is a diagram showing a wireless protocol structure in an LTE system according to an embodiment of the present disclosure.

[0056] Referring to FIG. 2, the wireless protocol of the LTE system consists of PDCP (Packet Data Convergence Protocol 2-110, 2-210), RLC (Radio Link Control 2-120, 2-220), and MAC (Medium Access Control 2-130, 2-230) at the terminal (2-100) and base station (2-200), respectively. The components of the wireless protocol may be referred to as layers, entities, or devices.

[0057] PDCP (Packet Data Convergence Protocol) (2-110, 2-210) is responsible for operations such as IP header compression and decompression. The main functions of PDCP are summarized as follows.

[0058] - Header compression and decompression features (ROHC only)

[0059] - User data transfer function (Transfer of user data)

[0060] - Sequential delivery function (In-sequence delivery of upper layer PDUs at PDCP re-establishment procedure for RLC AM)

[0061] - Order reordering function (For split bearers in DC (only support for RLC AM): PDCP PDU routing for transmission and PDCP PDU reordering for reception)

[0062] - Duplicate detection function (Duplicate detection of lower layer service data units (SDUs) at PDCP re-establishment procedure for RLC AM)

[0063] - Retransmission function (Retransmission of PDCP SDUs at handover and, for split bearers in DC, of ​​PDCP PDUs at PDCP data-recovery procedure, for RLC AM)

[0064] - Encryption and decryption functions (Ciphering and deciphering)

[0065] - Timer-based SDU discard in uplink.

[0066] Radio Link Control (hereinafter referred to as RLC) (2-120, 2-220) reconstructs PDCP Packet Data Units (PDUs) into an appropriate size to perform ARQ operations, etc. The main functions of RLC are summarized as follows.

[0067] - Data transfer function (Transfer of upper layer PDUs)

[0068] - ARQ function (Error Correction through ARQ (only for AM data transfer))

[0069] - Concatenation, segmentation, and reassembly functions (Concatenation, segmentation, and reassembly of RLC SDUs (only for UM and AM data transfer))

[0070] - Re-segmentation function (Re-segmentation of RLC data PDUs (only for AM data transfer))

[0071] - Reordering function (Reordering of RLC data PDUs (only for UM and AM data transfer)

[0072] - Duplicate detection function (only for UM and AM data transfer)

[0073] - Error detection function (Protocol error detection (only for AM data transfer))

[0074] - RLC SDU deletion function (RLC SDU discard (only for UM and AM data transfer))

[0075] RLC re-establishment function

[0076] MAC (2-130, 2-230) is connected to multiple RLC layer devices configured in a terminal and performs the operation of multiplexing RLC PDUs into MAC PDUs and demultiplexing RLC PDUs from MAC PDUs. The main functions of MAC are summarized as follows.

[0077] - Mapping function (Mapping between logical channels and transport channels)

[0078] - Multiplexing and demultiplexing function (Multiplexing / demultiplexing of MAC SDUs belonging to one or different logical channels into / from transport blocks (TB) delivered to / from the physical layer on transport channels)

[0079] - Scheduling information reporting function

[0080] - HARQ function (Error correction through HARQ)

[0081] - Priority handling between logical channels of one UE

[0082] - Priority handling between UEs by means of dynamic scheduling

[0083] - MBMS service identification function

[0084] - Transport format selection function

[0085] - Padding

[0086] The physical layer (2-140, 2-240) performs the operation of channel coding and modulating upper layer data, creating OFDM symbols to transmit over a wireless channel, or demodulating OFDM symbols received over a wireless channel and performing channel decoding to transmit to the upper layer.

[0087] FIG. 3 is a diagram showing the wireless protocol structure of a next-generation mobile communication system according to an embodiment of the present disclosure.

[0088] Referring to FIG. 3, the wireless protocol of the next-generation mobile communication system consists of NR SDAP (service data application protocol) (3-110, 3-210), NR PDCP (3-120, 3-220), NR RLC (3-130, 3-230), and NR MAC (3-140, 3-240) at the terminal (3-100) and the NR base station (3-200), respectively. The components of the wireless protocol may be referred to as layers, entities, or devices.

[0089] The main functions of NR SDAP (3-110, 3-210) may include some of the following functions.

[0090] - User data transfer function (transfer of user plane data)

[0091] - Mapping function between a QoS flow and a DRB for both DL and UL for uplink and downlink

[0092] - Marking QoS flow ID for uplink and downlink (marking QoS flow ID in both DL and UL packets)

[0093] - Function to map reflective QoS flow to data bearers for uplink SDAP PDUs (reflective QoS flow to DRB mapping for the UL SDAP PDUs).

[0094] Regarding the above SDAP layer device, the terminal may receive a radio resource control (RRC) message setting whether to use the header of the SDAP layer device or the functions of the SDAP layer device for each PDCP layer device, for each bearer, or for each logical channel. If the SDAP header is set, the terminal may be instructed to update or reset the mapping information for the QoS flow of the uplink and downlink and the data bearer using the NAS reflective QoS and AS reflective QoS 1-bit indicators of the SDAP header. The above SDAP header may include QoS flow ID information indicating QoS. The above QoS information may be used for data processing priority, scheduling information, etc., to support seamless service.

[0095] The main functions of NR PDCP (3-120, 3-220) may include some of the following functions.

[0096] Header compression and decompression (ROHC only)

[0097] - User data transfer function (Transfer of user data)

[0098] - Sequential delivery function (In-sequence delivery of upper layer PDUs)

[0099] - Out-of-sequence delivery of upper layer PDUs

[0100] - Reordering function (PDCP PDU reordering for reception)

[0101] - Duplicate detection function (Duplicate detection of lower layer SDUs)

[0102] - Retransmission of PDCP SDUs

[0103] - Encryption and decryption functions (Ciphering and deciphering)

[0104] - Timer-based SDU discard in uplink.

[0105] In the above, the reordering function of the NR PDCP device refers to a function of reordering PDCP PDUs received from a lower layer in order based on the PDCP SN (sequence number), and may include a function of transmitting data to an upper layer in the reordered order, or a function of transmitting immediately without considering the order, may include a function of recording lost PDCP PDUs by reordering, may include a function of performing a status report on lost PDCP PDUs to the transmitting side, and may include a function of requesting retransmission of lost PDCP PDUs.

[0106] The main functions of NR RLC(3-130, 3-230) may include some of the following functions.

[0107] - Data transfer function (Transfer of upper layer PDUs)

[0108] - Sequential delivery function (In-sequence delivery of upper layer PDUs)

[0109] - Out-of-sequence delivery of upper layer PDUs

[0110] - ARQ function (Error Correction through ARQ)

[0111] - Concatenation, segmentation, and reassembly functions of RLC SDUs

[0112] - Re-segmentation function (Re-segmentation of RLC data PDUs)

[0113] - Reordering function (Reordering of RLC data PDUs)

[0114] - Duplicate detection

[0115] - Error detection function (Protocol error detection)

[0116] - RLC SDU discard function

[0117] RLC re-establishment function

[0118] In the above, the in-sequence delivery function of the NR RLC device refers to a function that delivers RLC SDUs received from a lower layer to an upper layer in sequence; it may include a function to reassemble and deliver them if a single RLC SDU is received divided into multiple RLC SDUs; it may include a function to rearrange received RLC PDUs based on an RLC SN (sequence number) or PDCP SN (sequence number); it may include a function to record lost RLC PDUs after rearranging the order; it may include a function to perform a status report on lost RLC PDUs to the transmitting side; it may include a function to request retransmission of lost RLC PDUs; if there are lost RLC SDUs, it may include a function to deliver only the RLC SDUs prior to the lost RLC SDU to the upper layer in sequence; or if a predetermined timer has expired even if there are lost RLC SDUs, it may include a function to deliver all RLC SDUs received before the timer started to the upper layer in sequence; or It may include a function that delivers all RLC SDUs received so far to the upper layer in order when a predetermined timer expires, even if there are lost RLC SDUs.

[0119] In addition, the RLC PDUs described above may be processed in the order they are received (regardless of the order of the sequence number SN, in the order of arrival) and delivered to the PDCP device out of order (out-of-sequence delivery). If the received RLC PDU is a segment, the segments stored in the buffer or to be received later may be received, reconstructed into a complete RLC PDU, processed, and delivered to the PDCP device. The NR RLC layer may not include a concatenation function, and this function may be performed by the NR MAC layer or replaced by the multiplexing function of the NR MAC layer.

[0120] In the above, the out-of-sequence delivery function of the NR RLC device refers to a function of delivering RLC SDUs received from a lower layer directly to an upper layer regardless of order, and may include a function of reassembling and delivering them when a single RLC SDU is received divided into multiple RLC SDUs, and may include a function of storing the RLC SN or PDCP SN of the received RLC PDUs and sorting the order to record the lost RLC PDUs.

[0121] The NR MAC (3-140, 3-240) can be connected to multiple NR RLC layer devices configured in a terminal, and the main functions of the NR MAC may include some of the following functions.

[0122] - Mapping function (Mapping between logical channels and transport channels)

[0123] - Multiplexing and demultiplexing functions (Multiplexing / demultiplexing of MAC SDUs)

[0124] - Scheduling information reporting function

[0125] - HARQ function (Error correction through HARQ)

[0126] - Priority handling between logical channels of one UE

[0127] - Priority handling between UEs by means of dynamic scheduling

[0128] - MBMS service identification function

[0129] - Transport format selection function

[0130] - Padding

[0131] The NR PHY layer (3-150, 3-250) can perform the operation of channel coding and modulating upper layer data, creating OFDM symbol bundles and transmitting them to the wireless channel, or demodulating OFDM symbols received through the wireless channel and performing channel decoding to transmit them to the upper layer.

[0132] Meanwhile, New Radio (NR), used in 5th generation mobile communication systems (5G), is a wireless communication standard designed to support high-speed, high-capacity data transmission. Hybrid Automatic Repeat Request (HARQ) and Link Adaptation technology are utilized as key mechanisms to ensure efficient and reliable data transmission in NR systems. HARQ is a technology that enhances data transmission reliability by detecting errors during transmission and retransmitting data when necessary, while Link Adaptation technology dynamically adjusts the Modulation and Coding Scheme (MCS) according to variations in the wireless environment. Unlike the existing Automatic Repeat Request (ARQ) method, which retransmits packets whenever a transmission error occurs, HARQ can be combined with Forward Error Correction (FEC) techniques to correct errors by combining previously received data with retransmitted data. HARQ provides higher transmission efficiency and reliability than simple retransmission request methods and plays a crucial role, particularly in 5G systems that must handle large-scale data traffic.

[0133] <NR 시스템에서의 HARQ 동작 과정>

[0134] The transmitting end (base station or gNB) transmits a data packet to the receiving end (terminal, UE), and the receiving end determines whether the data was successfully received after receiving the data. At this time, if there are no errors in the received data, the receiving end sends an ACK (Acknowledgment) signal to the transmitting end to acknowledge successful reception, and if an error occurs, it sends a NACK (Negative Acknowledgment) signal to request retransmission.

[0135] NR's HARQ operates using a 1-bit feedback method. That is, the receiver feeds back a 1-bit signal in the form of an ACK or NACK to the transmitter to indicate whether the transmission was successful or if an error occurred. If an ACK signal is received, the transmitter sends the next data, and if a NACK signal is received, it retransmits the same data. This process is repeated until the transmitted data is successfully received, and even if data is retransmitted multiple times, the receiver can combine the data received from each transmission to use for error correction.

[0136] HARQ in NR systems is designed to reconstruct received data using Forward Error Correction (FEC) and improve the Signal-to-Noise Ratio (SNR), enabling data recovery with fewer retransmissions. This reduces the number of retransmissions, minimizes transmission delays, and optimizes system capacity. Additionally, HARQ in NR can be implemented in synchronous or asynchronous modes. Synchronous HARQ operates by pre-determining the timing of transmission and retransmission, whereas asynchronous HARQ allows transmission and retransmission to occur as needed without being constrained by timing, enabling more flexible resource management depending on network conditions.

[0137] <NR 시스템에서의 링크 적응(Link Adaptation) 기술>

[0138] In NR systems, Link Adaptation technology is used for efficient data transmission, which is an important function that dynamically adjusts the Modulation and Coding Scheme (MCS) according to variations in the wireless environment. This Link Adaptation aims to maximize data transmission speed and simultaneously minimize transmission errors by selecting the optimal MCS based on wireless channel conditions.

[0139] In NR systems, MCS correction is achieved by utilizing HARQ feedback and the Channel Quality Indicator (CQI). First, HARQ feedback serves to inform the transmitter whether data transmission was successful or if retransmission is required. After the receiver (terminal, UE) receives data, it feeds back the success or failure of the data to the transmitter (base station or gNB) via a Positive Acknowledgment (ACK) or Negative Acknowledgment (NACK) signal. If a NACK signal is transmitted, the transmitter retransmits the data, thereby allowing for the correction of reception errors. The receiver periodically reports the CQI to the transmitter to convey the current quality status of the radio channel. The CQI is calculated based on the radio channel's Signal-to-Noise Ratio (SNR) and interference conditions, and the transmitter utilizes this information to select an MCS suitable for the current channel conditions. For example, when channel conditions are good, the transmitter can increase the data transmission speed by selecting a high modulation and encoding scheme, and conversely, when channel conditions are poor, it can minimize the occurrence of errors by selecting a low modulation and encoding scheme.

[0140] In this process, HARQ feedback and CQI information act complementarily. HARQ feedback helps ensure transmission reliability based on the success of actual data transmission, while CQI predicts channel conditions in advance to select the optimal MCS. Through this, data transmission efficiency and reliability of the NR system can be maximized by implementing Link Adaptation and dynamically adjusting the MCS. In particular, MCS correction plays a crucial role in maintaining optimal communication performance in various wireless environments. Since 5G NR must operate not only in environments requiring ultra-high-speed communication but also in situations demanding high reliability and low latency, MCS correction based on HARQ feedback and CQI serves as a core technology to meet these requirements. MCS correction in NR systems is achieved through Link Adaptation techniques utilizing HARQ feedback and CQI information, thereby optimizing transmission efficiency and reliability and enabling optimal data transmission in diverse wireless environments.

[0141] However, HARQ and Link Adaptation (LA) mechanisms operate primarily by relying on 1-bit HARQ feedback and CQI feedback. This method causes several limitations in accurately determining the real-time channel status of the terminal at the base station, which makes it difficult to optimize the performance of interference control or link adaptation.

[0142] First, HARQ feedback consists of 1 bit, and an ACK (positive acknowledgment) or NACK (negative acknowledgment) signal is transmitted to the base station, indicating only whether the data transmitted by the terminal has been successfully received. While 1-bit feedback can clearly distinguish the success or failure of data transmission, it has limitations in identifying the specific causes of the terminal's channel status or performance degradation. In other words, it is impossible to analyze the cause of data transmission failure based solely on information indicating whether the transmission was successful or failed. For example, it is not possible to make an accurate diagnosis as to whether the data transmission failure was due to the selection of an inappropriate MCS (Modulation and Coding Scheme), weak signal strength of the terminal, or severe interference.

[0143] Second, while CQI feedback serves to report the terminal's channel status to the base station, it primarily represents the average quality of the channel experienced by the terminal. CQI is calculated based on the signal-to-noise ratio (SNR) of the frequency band currently used by the terminal, and it is difficult to clearly identify the actual cause of performance degradation based on this information alone. In particular, when a terminal is in an interference environment, the CQI value may appear to indicate a normal channel state, but actual communication performance may be degraded due to the interference. Base stations find it difficult to recognize such performance degradation caused by interference solely through CQI feedback, and there is a high probability that they will assign an inappropriate MCS by simply judging the channel status to be good.

[0144] Third, in HARQ systems that utilize only 1-bit HARQ feedback and CQI feedback, the accuracy of MCS allocation may be compromised. If the MCS assigned by the base station to a terminal is inappropriate, even if data transmission fails, the base station merely recognizes it as a transmission failure and cannot specifically determine whether the MCS was inappropriate, the terminal's signal strength was weak, or interference was the cause. This degrades the link adaptation performance required for the base station to select an appropriate MCS for the terminal, leading to repeated retransmissions. Consequently, this can result in inefficient resource management and network performance degradation.

[0145] HARQ and link adaptation methods rely on limited feedback information, making accurate channel state analysis and interference control difficult. This can lead to reduced transmission efficiency due to the failure of proper MCS allocation. This results in significantly degraded performance, particularly in environments with weak terminal signal strength or severe interference, and can negatively impact overall network performance and user experience.

[0146] Figures 4a and 4b are examples to illustrate interference situations that vary depending on the resource allocation of interference signals.

[0147] Referring to FIG. 4a, the first UE (UE #0) can receive a desired signal from the first cell (Cell #0). While receiving the desired signal, the first UE (UE #0) may be affected by interference caused by a signal transmitted from the second cell (Cell #1) to the second UE (UE #1). At this time, a plurality of RBGs (Resource Block Groups) (e.g., RBG 0 to RBG 17) may be allocated on the frequency axis for the signal transmitted from the first cell (Cell #0) (Tx signal from cell 0), and a single RBG (e.g., RBG 10) may be allocated on the frequency axis for the signal transmitted from the second cell (Cell #1) (Tx signal from cell 1). As shown in Fig. 4a, when a small frequency resource is allocated to an interference signal (or in a situation where short buffer occupancy is the source of interference), the overhead for utilizing interference control techniques such as joint transmission and multi-TRP may not be higher than the expected gain, and a simple method of simply not allocating resources to one RBG (e.g., RBG 10) of the first cell (Cell #0) may be effective for interference control of the cell.

[0148] Referring to FIG. 4b, the first UE (UE #0) can receive a desired signal from the first cell (Cell #0). While receiving the desired signal, the first UE (UE #0) may be affected by interference caused by a signal transmitted from the second cell (Cell #1) to the second UE (UE #1). At this time, a plurality of RBGs (Resource Block Groups) (e.g., RBG 0 to RBG 17) may be assigned on the frequency axis for the signal transmitted from the first cell (Cell #0) (Tx signal from cell 0), and the same plurality of RBGs (e.g., RBG 0 to RBG 17) may be assigned on the frequency axis for the signal transmitted from the second cell (Cell #1) (Tx signal from cell 1). As shown in Fig. 4b, when a large amount of frequency resources are allocated to an interference signal (or in a situation where a Heavy BO is the source of interference), it is difficult to obtain performance gains in interference control through simple scheduling avoidance alone, and interference can be controlled by applying interference control techniques such as joint transmission through channel information exchange and multi-TRP even if certain overhead (OH) is considered.

[0149] However, regarding the method of obtaining terminal channel information through CQI and HARQ, the HARQ information received by the base station is the same as Nack, regardless of whether the amount of RB (Resource Block) causing interference is large or small. However, in terms of interference control, the interference situations in Fig. 4a and Fig. 4b may each require the application of completely different techniques, and the need for a method to resolve this is emerging.

[0150] Figures 5a and 5b are diagrams illustrating a method for estimating the state of a UE channel using link application technology.

[0151] Referring to Fig. 5a, the base station can obtain SINR_IIR(k) from the terminal's CQI report. Whenever the base station receives a Nack message from the terminal, it can lower the SINR estimate (Estimated SINR) by NackStepSize, or whenever it receives an Ack message from the terminal, it can raise the SINR estimate (Estimated SINR) by AckStepSize (SINRwithOLRC = SINR_IIR + OLRC_OFFSET(Step Size)). That is, the base station can estimate the SINR corresponding to the terminal's channel condition using the Nack message or Ack message received from the terminal.

[0152] Referring to Fig. 5b, the base station can obtain SINR_IIR(k) from the terminal's CQI report. Whenever the base station receives an Ack message from the terminal, it can increase the SINR estimate (Estimated SINR) by AckStepSize (SINRwithOLRC = SINR_IIR + OLRC_OFFSET(Step Size)). That is, the base station can estimate the SINR corresponding to the terminal's channel condition using multiple Ack messages received from the terminal.

[0153] Referring to FIGS. 5a and 5b, when the terminal's CQI feedback differs from the actual electric field conditions, the terminal can operate by predicting the channel state through link adaptation technology; however, it may take a long time to predict and match the terminal channel state from the SINR estimated from the CQI report (latency increases as the terminal receives up to n times until it receives through retransmission). In particular, although the response method differs depending on whether the terminal's performance degradation is due to interference or electric field degradation, it may be difficult to identify the channel environment using only HARQ feedback and CQI feedback. For example, JT, HO, Power boosting, waveform modification, etc., can be applied in the event of electric field degradation, and in the event of performance degradation due to interference, interference control methods may be applied differently depending on the resource allocation of the interference source, as described in FIG. 4a or FIG. 4b.

[0154] The present disclosure proposes a method for adding information required for interference control and / or link adaptation (LA) of a base station to HARQ feedback and transmitting it (e.g., adding a minimum number of bits) based on measurement information of a terminal. According to one embodiment, the information required for interference control and LA may include at least one of the following: the difference between the decoding SINR and the SINR assumed in the MCS allocated from the base station, the number of retransmissions required for the terminal to successfully decode, the type of interference experienced by the terminal, whether a Nack is detected due to interference, and whether a Nack is detected due to a drop in electric field.

[0155] The method and apparatus according to the embodiments of the present disclosure can prevent UE throughput degradation caused by appropriate MCS selection, reduce latency by reducing the number of HARQ process iterations for retransmission, and improve system throughput through interference control by providing information necessary for interference control and / or LA of a base station in addition to HARQ feedback.

[0156] The method and apparatus according to the embodiments of the present disclosure may use at least one of the following methods (Examples 1) to (7) to provide information necessary for interference control and / or LA of a base station by adding it to HARQ feedback. The method and apparatus according to the embodiments of the present disclosure may use at least one of the following methods in combination.

[0157] (Example 1) MCS difference reporting method for LA

[0158] (Example 2) Method for reporting the number of required retransmissions

[0159] (Example 3) Preset for MCS difference reporting or retransmission count reporting

[0160] (Example 4) Method for reporting interference or electric field weakening

[0161] (Example 5) Preset method for reporting interference or electric field weakening

[0162] (Example 6) Method for reporting interference types

[0163] (Example 7) Preset method for interference type reporting

[0164] Below, specific descriptions of each of (Examples 1) to (Examples 7) of the present disclosure are provided.

[0165] (Example 1) MCS difference reporting method for accurate link adaptation (LA)

[0166] FIG. 6 is a flowchart illustrating an MCS indicator reporting method for link adaptation (LA) according to one embodiment of the present disclosure.

[0167] Referring to FIG. 6, in operation 610, the base station (601) can transmit downlink control information (DCI) to the terminal (603) via the Physical Downlink Control Channel (PDCCH) and transmit data to the terminal (603) via the Physical Downlink Shared Channel (PDSCH).

[0168] In operation 620, the terminal (603) may attempt PDSCH decoding based on the DCI received via PDCCH. After receiving the DCI, the terminal (603) may receive data via PDSCH. The terminal (603) may identify (or confirm) the MCS determined by the base station (601) based on the DCI received via PDSCH.

[0169] In operation 630, the terminal (603) can compare the first SINR assumed in the MCS of the PDSCH with the second SINR received by the terminal (603). The terminal (603) can estimate (or guess) the second SINR of the receiving channel in the DMRS (Demodulation Reference Signal), PDSCH, etc. when receiving the PDSCH. The terminal (603) can check (or determine) the difference value between the first SINR corresponding to the MCS of the PDSCH and the second SINR received by the terminal (603), compare the difference value with a threshold value, and check (or determine) whether the difference value is greater than or less than the threshold value.

[0170] In operation 640, the terminal (603) may generate an MCS indicator for LA (or information regarding the result of comparing the difference value and the threshold value) and an Ack / Nack feedback for the HARQ operation. According to one embodiment, the MCS indicator for LA may include at least one indicator regarding the result of comparing the difference value of the first SINR corresponding to the MCS of the PDSCH and the second SINR received by the terminal (603) with at least one threshold value. In (Embodiment 1), a method is proposed to report the difference between the SINR corresponding to the MCS assigned by the base station (601) and the SINR of the receiving channel actually experienced by the terminal (603) in the Ack / Nack feedback.

[0171] In operation 650, the terminal (603) may transmit Ack feedback and an MCS indicator for LA (or information regarding the result of comparing the difference value and the at least one threshold value) to the base station (601) upon successful decoding for HARQ operation. The terminal (603) may transmit Nack feedback and an MCS indicator (or information regarding the result of comparing the difference value and the threshold value) to the base station (601) upon failure of decoding for HARQ operation.

[0172] According to one embodiment, the terminal (603) can determine an appropriately decodingable MCS from the estimated (or guessed) SINR and transmit information regarding the determination result to the base station (601) along with Ack / Nack feedback. According to one embodiment, when the base station (601) assigns MCS X to the terminal (603), the terminal (603) can report to the base station (601) that decoding is possible even if an MCS higher than MCS X by a threshold value (Th) is assigned based on the perceived SINR. According to one embodiment, when the base station (601) assigns MCS X to the terminal (603), the terminal (603) can report to the base station (601) that decoding is possible only if an MCS lower than MCS X by a threshold value (Th) is assigned based on the perceived SINR. According to one embodiment, when a base station (601) assigns MCS number X to a terminal (603), the terminal (603) may report to the base station (601) that the perceived SINR and MCS number X are similarly matched based on the perceived SINR.

[0173] In operation 660, the base station (601) can perform an operation based on an MCS indicator for HARQ-based retransmission and LA (or information regarding the result of comparing the difference value and the at least one threshold value).

[0174] According to one embodiment, the MCS indicator for LA (or information regarding the result of comparing the difference value and the at least one threshold value) may be determined based on the 2-bit feedback method of Table 1. The MCS indicator values ​​of Table 1 are merely examples set for convenience of explanation, and each MCS indicator value may be implemented by changing it to various values. According to one embodiment, the MCS indicator for HARQ Ack / Nack and LA (or information regarding the result of comparing the difference value and the at least one threshold value) may consist of consecutive N-bits (where N is a natural number greater than or equal to 2). According to one embodiment, each of the MCS indicator for HARQ Ack / Nack and LA (or information regarding the result of comparing the difference value and the at least one threshold value) may be set and / or transmitted independently. According to one embodiment, the MCS indicator for LA may be set and / or transmitted independently of HARQ Ack / Nack through RRC signaling, MAC CE, or pre-agreed signaling.

[0175] [Table 1]

[0176]

[0177] Referring to Table 1, if the MCS indicator for LA is "00", the terminal (603) can notify the base station (601) that decoding has failed and that the difference between the first SINR assumed in the MCS and the second SINR received is within a preset threshold. The base station (601) performs retransmission for the corresponding TB (Transport Block) or CBG (Code Block Group) and may lower or not lower the OLRC (Outer Loop Rate Control) offset (at least not raise it). When transmitting data, the base station (601) may divide a large data TB into small code blocks and generate a CBG by grouping them again.

[0178] Referring to Table 1, when the MCS indicator for LA is "01", the terminal (603) can notify the base station (601) that decoding has failed and that the difference between the first SINR assumed in the MCS and the second SINR received is greater than a preset threshold. The base station (601) performs retransmission for the corresponding TB or CBG and can lower the OLRC offset even further than it was lowered from the MCS indicator "00".

[0179] Referring to Table 1, when the MCS indicator for LA is "10", the terminal (603) can notify the base station (601) that decoding was successful and that the difference between the first SINR assumed in the MCS and the received second SINR is within a preset threshold. The base station (601) may increase or not increase the OLRC offset for the corresponding TB (at least not decrease it).

[0180] Referring to Table 1, when the MCS indicator for LA is "11", the terminal (603) can notify the base station (601) that decoding has been successful and that the difference between the first SINR assumed in the MCS and the second SINR received is greater than a preset threshold. The base station (601) can increase the OLRC offset for the corresponding TB more than it was at the MCS indicator "10".

[0181] In the example of Table 1, the MSB (Most Significant Bit) (or most significant bit) of the MCS indicator indicates whether the terminal (603) has succeeded in decoding, and the LSB (Least Significant Bit) (or least significant bit) of the MCS indicator may indicate whether the difference between the MCS assigned and the SINR experienced during decoding is within or greater than a preset threshold when the terminal (603) fails to decode.

[0182] According to one embodiment, an MCS indicator for LA (or information regarding the result of comparing the difference value and the at least one threshold value) may be determined based on the 3-bit feedback method of Table 2. The MCS indicator values ​​of Table 2 are merely examples set for convenience of explanation, and each MCS indicator value may be changed and implemented to various values.

[0183] [Table 2]

[0184]

[0185] Referring to Table 2, if the MCS indicator for the LA is "000", the terminal (603) can notify the base station (601) that decoding has failed and that a difference within the smallest preset first threshold value (Threshold_0) has occurred between the first SINR corresponding to the MCS and the received second SINR. The base station (601) performs retransmission for the corresponding TB or CBG and may or may not lower the OLRC offset (at least may not raise it).

[0186] Referring to Table 2, if the MCS indicator for the LA is "001", the terminal (603) can notify the base station (601) that decoding has failed and that there is a difference within a preset second smallest second threshold value (Threshold_1) between the first SINR corresponding to the MCS and the received second SINR. The base station (601) performs retransmission for the corresponding TB or CBG and may or may not lower the OLRC offset (at least may not raise it).

[0187] Referring to Table 2, if the MCS indicator for the LA is "010", the terminal (603) can notify the base station (601) that decoding has failed and that a difference within the largest pre-set third threshold value (Threshold_2) has occurred between the first SINR corresponding to the MCS and the received second SINR. The base station (601) performs retransmission for the corresponding TB or CBG and may or may not lower the OLRC offset (at least may not raise it).

[0188] Referring to Table 2, if the MCS indicator for the LA is "011", the terminal (603) can notify the base station (601) that decoding has failed and that a difference greater than the preset largest third threshold value (Threshold_2) has occurred between the first SINR corresponding to the MCS and the received second SINR. The base station (601) performs retransmission for the corresponding TB or CBG and may or may not lower the OLRC offset (at least may not raise it).

[0189] Referring to Table 2, when the MCS indicator for LA is "100", the terminal (603) can notify the base station (601) that decoding has been successful and that a difference within the smallest first threshold value (Threshold_0) set between the first SINR corresponding to the MCS and the received second SINR has occurred. The base station (601) may increase or not increase the OLRC offset (at least may not decrease it).

[0190] Referring to Table 2, when the MCS indicator for LA is "101", the terminal (603) can notify the base station (601) that decoding has been successful and that a difference within the second smallest second threshold value (Threshold_1) set between the first SINR corresponding to the MCS and the received second SINR has occurred. The base station (601) may increase or not increase the OLRC offset (at least may not decrease it).

[0191] Referring to Table 2, when the MCS indicator for LA is "110", the terminal (603) can notify the base station (601) that decoding has been successful and that a difference within the largest preset second threshold value (Threshold_2) has occurred between the first SINR corresponding to the MCS and the received second SINR. The base station (601) may increase or not increase the OLRC offset (at least may not decrease it).

[0192] Referring to Table 2, when the MCS indicator for LA is "111", the terminal (603) can notify the base station (601) that decoding has been successful and that a difference greater than the preset largest third threshold value (Threshold_2) has occurred between the first SINR corresponding to the MCS and the received second SINR. The base station (601) may increase or not increase the OLRC offset (at least may not decrease it).

[0193] According to one embodiment, at least one threshold value set for an MCS indicator for LA may be set to a prior agreement between base station terminals, radio resource control (RRC) signaling, medium access control element (MAC CE), or a prior agreement.

[0194] In Tables 1 and 2, for convenience of explanation, cases where the MCS indicator for LA is implemented with 2 bits or 3 bits are described, but the technical concept of the present disclosure is not limited thereto, and the MCS indicator for LA can be implemented with 3 bits or more.

[0195] Table 2 describes the case where the HARQ bit is used as the MSB, and when performing a CBG-based HARQ operation, a bit can be added to the CBG's codebook. According to one embodiment, when the CBG's codebook is 8 bits, the terminal (603) can transmit XXXXXXXXY or XXXXXXXXYY by adding an additional feedback 1 bit (Y) or feedback 2 bits (YY) according to an embodiment of the present disclosure to the CBG's codebook XXXXXXXX. In this case, X and Y represent placeholders for the 1-bit feedback, and their values ​​are set to 0 or 1, and X and Y can each have different values.

[0196] FIGS. 7a and 7b are drawings illustrating the change in the estimated SINR value of the link application (LA) operation during feedback according to one embodiment of the present disclosure.

[0197] Referring to FIG. 7a, the base station receives a CQI report and an MCS indicator for LA from the terminal, and can obtain SINR_IIR(k) based on the CQI report and the MCS indicator. The base station can lower the SINR estimate (Estimated SINR) by an amount equal to the NackStepSize set based on the terminal's reporting. The base station can raise the SINR estimate (Estimated SINR) by an amount equal to the AckStepSize set based on the terminal's reporting. Subsequently, the base station does not raise or lower the SINR estimate (Estimated SINR) based on feedback.

[0198] Referring to FIG. 7b, the base station receives a CQI report and an MCS indicator for LA from the terminal, and can obtain SINR_IIR(k) based on the CQI report and the MCS indicator. The base station can increase the SINR estimate (Estimated SINR) by an AckStepSize set based on the terminal's reporting. Subsequently, the base station does not increase or decrease the SINR estimate (Estimated SINR) based on feedback.

[0199] Referring to FIGS. 7a and 7b, a link adaptation technique that takes into account the terminal's CQI feedback and actual electric field conditions can be used.

[0200] (Example 2) Method for reporting the number of required retransmissions

[0201] FIG. 8 is a flowchart for explaining a method for reporting the number of required retransmissions of a terminal according to one embodiment of the present disclosure.

[0202] Referring to FIG. 8, in operation 810, the base station (801) can transmit DCI (downlink control information) to the terminal (803) through the PDCCH (Physical Downlink Control Channel) and transmit data to the terminal (803) through the PDSCH (Physical Downlink Shared Channel).

[0203] In operation 820, the terminal (803) may attempt PDSCH decoding based on the DCI received via PDCCH. After receiving the DCI, the terminal (803) may receive data via PDSCH. The terminal (803) may identify (or verify) the MCS determined by the base station (801) based on the DCI received via PDSCH.

[0204] In operation 830, the terminal (803) can calculate the number of required retransmissions by referring to at least one of the LLR (Log-Likelihood Ratio) value, the decoding SINR value, and the MCS value when a NACK occurs while performing PDSCH decoding.

[0205] In operation 840, the terminal (803) can generate an indicator indicating Nack feedback for HARQ operation and the number of required retransmissions. In operation 850, the terminal (803) can transmit the indicator indicating Nack feedback and the number of required retransmissions to the base station (801).

[0206] In operation 860, the base station (801) can perform operations based on HARQ-based retransmission and the number of required retransmissions.

[0207] Due to the characteristics of NR, a very low delay may be required depending on the characteristics of the terminal (803). In this case, the existing retransmission framework may generate NACK feedback up to four times to receive the corresponding retransmission. However, due to the transmission of many NACKs, the delay requirement of the terminal (803) may not be met. Embodiment 2 of the present disclosure proposes a method to reduce the number of retransmissions by utilizing additional bits when reporting NACK feedback.

[0208] According to one embodiment, considering the case where an additional 1 bit indicating the number of required retransmissions is transmitted in addition to the HARQ operation, feedback as shown in Table 3 can be considered. According to one embodiment, the HARQ Ack / Nack and the number of required retransmissions indicator may consist of consecutive N-bits (where N is a natural number greater than or equal to 2). According to one embodiment, the HARQ Ack / Nack and the number of required retransmissions indicator may each be set and / or transmitted independently. According to one embodiment, the number of required retransmissions indicator may be set and / or transmitted independently of the HARQ Ack / Nack through RRC signaling, MAC CE, or pre-agreed signaling.

[0209] [Table 3] 2-bit feedback method

[0210]

[0211] Referring to Table 3, if the 2-bit HARQ Nack feedback is "00", the terminal (803) may report to the base station (801) that decoding failed and that at least one retransmission is required to receive the data. The base station (801) performs one retransmission for the corresponding TB or CBG and may or may not lower the OLRC offset (at least may not raise it).

[0212] Referring to Table 3, if the 2-bit HARQ Nack feedback is "01", the terminal (803) may report to the base station (801) that decoding failed and that at least three retransmissions are required to receive the data. The base station (801) performs three retransmissions for the corresponding TB or CBG and may or may not lower the OLRC offset (at least may not raise it).

[0213] According to one embodiment, the base station (801) may retransmit to the terminal (803) as many times as necessary, or perform retransmissions greater than or less than the necessary number of retransmissions based on the existing history. For example, according to the framework of NR, when retransmitting once, only RV (Redundancy Version) 2 may be transmitted; when retransmitting twice, RV2 and RV3 may be retransmitted; when retransmitting three times, RV2, RV3, and RV1 may all be retransmitted; or when retransmitting three or more times, starting from RV0, RV2, RV3, and RV1 may be retransmitted repeatedly in sequence.

[0214] According to one embodiment, the MSB in the 2-bit HARQ Nack feedback may indicate Ack / Nack feedback. According to one embodiment, each of the Nack feedback and retransmission count indicators in Table 3 may be transmitted independently through a separate message (or information).

[0215] According to one embodiment, if we consider the case where 2 bits indicating the number of required retransmissions are additionally transmitted in addition to the HARQ operation, feedback such as that shown in Table 4 can be considered.

[0216] [Table 4] 3-bit feedback method

[0217]

[0218] Referring to Table 4, if the 3-bit HARQ Nack feedback is "000", the terminal (803) can notify the base station (801) that decoding has failed and data reception is impossible. The base station (801) performs retransmission for the corresponding TB or CBG, and may lower or not lower the OLRC offset (at least not raise it). Alternatively, the base station (801) may determine the situation of the terminal (803) and lower the MCS to perform retransmission. Alternatively, the base station (801) may retransmit to the terminal (803) a maximum number of times, or consider packet drop, initiate handover, etc. without retransmitting.

[0219] Referring to Table 4, if the 3-bit HARQ Nack feedback is "001", the terminal (803) can notify the base station (801) that decoding has failed and that at least one retransmission is required to receive the data. The base station (801) performs one retransmission for the corresponding TB or CBG and may or may not lower the OLRC offset (at least may not raise it).

[0220] Referring to Table 4, if the 3-bit HARQ Nack feedback is "010", the terminal (803) can notify the base station (801) that decoding has failed and that at least two retransmissions are required to receive the data. The base station (801) performs two retransmissions for the corresponding TB or CBG and may or may not lower the OLRC offset (at least may not raise it).

[0221] Referring to Table 4, if the 3-bit HARQ Nack feedback is "011", the terminal (803) can notify the base station (801) that decoding has failed and that at least three retransmissions are required to receive the data. The base station (801) performs three retransmissions for the corresponding TB or CBG and may or may not lower the OLRC offset (at least may not raise it).

[0222] According to one embodiment, the base station (801) may retransmit to the terminal (803) as many times as necessary, or perform retransmissions greater than or less than the necessary number of retransmissions based on the existing history. For example, according to the framework of NR, when retransmitting once, only RV (Redundancy Version) 2 may be transmitted; when retransmitting twice, RV2 and RV3 may be retransmitted; when retransmitting three times, RV2, RV3, and RV1 may all be retransmitted; or when retransmitting three or more times, starting from RV0, RV2, RV3, and RV1 may be retransmitted repeatedly in sequence.

[0223] According to one embodiment, the MSB in the 3-bit HARQ Nack feedback may indicate Ack / Nack feedback. According to one embodiment, the Nack feedback and the 2-bit retransmission count indicator of Table 4 may each be transmitted independently through a separate message (or information).

[0224] According to one embodiment, when performing a CBG-based HARQ operation, additional bits may be added to the codebook of the CBG. For example, if the codebook of the CBG is 8 bits, an additional 1 bit of feedback (Y) or 2 bits of feedback (YY) may be added to the codebook XXXXXXXX of the CBG to transmit XXXXXXXXY or XXXXXXXXYY. In this case, X and Y represent placeholders for the 1-bit feedback, and their values ​​are set to 0 or 1, and each X and each Y may have different values.

[0225] FIG. 9a shows an example of a conventional retransmission operation of a base station based on Nack feedback of a terminal, and FIG. 9b and FIG. 9c show examples of retransmission operations of a base station based on Nack feedback of a terminal according to an embodiment of the present disclosure.

[0226] Referring to FIG. 9a, the base station (BS) can transmit control information to the terminal (UE) via PDCCH and transmit RV0 data to the terminal (UE) via PDSCH. When the terminal (UE) transmits Nack feedback to the base station (BS), the base station (BS) can transmit control information to the terminal (UE) via PDCCH and transmit RV2 data to the terminal (UE) via PDSCH. When the terminal (UE) transmits Nack feedback to the base station (BS), the base station (BS) can transmit control information to the terminal (UE) via PDCCH and transmit RV3 data to the terminal (UE) via PDSCH. When the terminal (UE) transmits Nack feedback to the base station (BS), the base station (BS) can transmit control information to the terminal (UE) via PDCCH and transmit RV1 data to the terminal (UE) via PDSCH. Subsequently, the terminal (UE) can transmit Ack feedback to the base station (BS).

[0227] Referring to FIGS. 9b and 9c, the base station (BS) can transmit control information to the terminal (UE) via PDCCH and transmit RV0 data to the terminal (UE) via PDSCH. Subsequently, the terminal (UE) can transmit Nack feedback and an indicator requesting three retransmissions to the base station (BS). At this time, the base station (BS) can transmit RV2, RV3, and RV1 data along with PDCCH control information corresponding to each RV to the terminal (UE) for three retransmissions, as shown in FIG. 9b; additionally, the base station (BS) can transmit control information to the terminal (UE) via PDCCH and transmit RV2, RV3, and RV1 data to the terminal (UE) via PDSCH, as shown in FIG. 9c. Additionally, if the terminal (UE) requests retransmission three or more times, the base station (BS) can retransmit sequentially, starting from RV0, then RV2, RV3, and RV1. Afterward, the terminal (UE) can send Ack feedback to the base station (BS). In FIGS. 9b and 9c, by the terminal (UE) sending an indicator requesting three retransmissions along with Ack feedback to the base station (BS), the base station (BS) can transmit the retransmission data at once, thereby reducing the delay.

[0228] According to one embodiment, in FIG. 9b, the terminal (UE) may assume the same HARQ Process ID for multiple PDCCHs and multiple PDSCHs transmitted by the base station (BS), and accordingly, transmit a single HARQ Feedback for multiple PDCCHs and multiple PDSCHs. That is, the terminal (UE) may transmit a single integrated HARQ Feedback for multiple RVs.

[0229] According to one embodiment, in FIG. 9b, the terminal (UE) can transmit one HARQ Feedback for each of the multiple RVs for the multiple PDCCHs and multiple PDSCHs transmitted by the base station (BS).

[0230] According to one embodiment, in FIG. 9c, the terminal (UE) may assume the same HARQ Process ID for one PDCCH and multiple PDSCHs transmitted by the base station (BS), and accordingly, transmit one HARQ Feedback for one PDCCH and multiple PDSCHs. That is, the terminal (UE) may transmit one integrated HARQ Feedback for multiple RVs.

[0231] According to one embodiment, in FIG. 9c, the terminal (UE) can transmit multiple HARQ Feedbacks for each of the multiple RVs for one PDCCH and multiple PDSCHs transmitted by the base station (BS).

[0232] (Example 3) Preset for MCS difference reporting or retransmission count reporting

[0233] FIG. 10 illustrates an example of a pre-configured method between a base station and a terminal for reporting MCS difference or retransmission counts according to one embodiment of the present disclosure.

[0234] Referring to FIG. 10, in operation 1010, the terminal (1003) may transmit terminal capability information (UE capability) regarding MCS difference reporting and / or retransmission count reporting to the base station (1001). According to one embodiment, the terminal (1003) may transmit terminal capability information (UE capability) to the base station (1001) including information regarding whether SINR measurement is possible upon PDSCH reception for MCS difference reporting. According to one embodiment, the terminal (1003) may transmit terminal capability information (UE capability) to the base station (1001) including information indicating that a necessary HARQ can be estimated when a decoding failure occurs for retransmission count reporting.

[0235] In operation 1020, the base station (1001) may transmit configuration information for reporting MCS difference and / or retransmission counts to the terminal (1003). According to one embodiment, the base station (1001) may transmit configuration information for reporting MCS difference and / or retransmission counts to the terminal (1003) via RRC signaling. According to one embodiment, the base station (1001) may transmit configuration information for reporting MCS difference and / or retransmission counts to the terminal (1003) via MAC CE.

[0236] According to one embodiment, the base station (1001) may set a method for setting additional bits when reporting HARQ for MCS difference reporting and / or retransmission count reporting to the terminal (1003). According to one embodiment, the base station (1001) may transmit to the terminal (1003) an additional bit number for feedback (e.g., selected from {1 bit, 2 bits, 2 bits}) and a threshold value corresponding to 2 (additional bit number) - 1 (e.g., a value used in Example 1 and Example 2).

[0237] The base station (1001) starts a timer after transmitting setting information for MCS difference reporting and / or retransmission count reporting, and when the timer expires, it can perform the operation of the aforementioned embodiment 1 and / or embodiment 2 in operation 1030.

[0238] The terminal (1003) starts a timer after receiving setting information for reporting the MCS difference and / or the number of retransmissions, and when the timer expires, it can perform the operation of the aforementioned Example 1 and / or Example 2 in the 1040 operation.

[0239] FIG. 11 illustrates another example of a preset method between a base station and a terminal for reporting MCS difference or retransmission counts according to one embodiment of the present disclosure.

[0240] Referring to FIG. 11, in operation 1110, the base station (1101) may include an indicator in the DCI that instructs the terminal (1103) to perform an operation corresponding to an MCS difference report or a retransmission count report when assigning a PDSCH to the DCI. According to one embodiment, the indicator may be implemented as 1 bit (or 2 bits) to indicate whether the operation corresponding to the MCS difference report and / or the retransmission count report is in an on / off state.

[0241] In operation 1120, the terminal (1103) may perform an operation according to the aforementioned embodiment 1 or embodiment 2 during PDSCH decoding.

[0242] According to one embodiment, if the base station (1101) indicates through DCI that the operation corresponding to MCS difference reporting or retransmission count reporting is on, but the base station (1101) has not previously transmitted setting information for MCS difference reporting or retransmission count reporting, the terminal (1103) can perform the operation of MCS difference reporting or retransmission count reporting using a default value.

[0243] According to one embodiment, even if the base station (1101) does not specify an operation corresponding to MCS difference reporting or retransmission count reporting as DCI, if it has previously been set for MCS difference reporting or retransmission count reporting, it can perform an operation for MCS difference reporting or retransmission count reporting in the HARQ resource set as DCI.

[0244] FIG. 12 illustrates another example of a preset method between a base station and a terminal for reporting MCS difference or retransmission counts according to one embodiment of the present disclosure.

[0245] Referring to FIG. 12, in operation 1210, the base station (1201) may include an indicator in the DCI that instructs the terminal (1203) not to perform an operation corresponding to an MCS difference report or a retransmission count report when assigning a PDSCH to the DCI.

[0246] In operation 1220, the terminal (1203) can perform PDSCH decoding.

[0247] (Example 4) Report of interference or electric field weakening

[0248] FIG. 13 is a flowchart illustrating a method for reporting interference or electric field weakening of a terminal according to one embodiment of the present disclosure.

[0249] Referring to FIG. 13, in operation 1310, the base station (1301) can transmit DCI to the terminal (1303) via PDCCH and transmit data to the terminal (1303) via PDSCH.

[0250] In operation 1320, the terminal (1303) may attempt PDSCH decoding based on the DCI received via PDCCH. After receiving the DCI, the terminal (1303) may receive data via PDSCH.

[0251] In the 1330 operation, the terminal (1303) can determine whether the decoding failure is due to interference or due to a drop in electric field from at least one of DMRS RSRP (Reference Signal Received Power), decoding SINR, and CRS (Cell-specific Reference Signal) when a NACK occurs while performing PDSCH decoding.

[0252] In operation 1340, the terminal (1303) can generate Nack feedback for HARQ operation and an indicator indicating whether there is field degradation or interference. In operation 1350, the terminal (1303) can transmit the Nack feedback and the indicator indicating whether there is field degradation or interference to the base station (1301). When reception fails, the terminal (1303) can determine whether the cause of the reception failure is reception signal degradation (i.e., field weakening) or performance degradation due to interference. Depending on the cause of the reception failure experienced by the terminal (1303), the operation of the base station (1301) to resolve it may vary. Since the base station (1301) only receives Ack / Nack feedback for the transmission, it is difficult to determine whether the cause of the reception failure of the terminal (1303) is due to field weakening or interference. To resolve this situation, information known by the terminal (1303) can be transmitted to the base station (1301) in the form of feedback. According to one embodiment, the terminal (1303) can determine whether, when PDSCH decoding fails, (1) the decoding failed because the magnitude of the received signal is small compared to the noise, or (2) the decoding failed because the magnitude of the received signal is sufficiently large but interference from another cell is present.

[0253] In operation 1360, the base station (1301) can perform the required operation based on HARQ-based retransmission and an indicator indicating whether there is a drop in electric field or interference.

[0254] According to one embodiment, the terminal (1303) may inform the base station (1301) whether the reason for the decoding failure is (1) field weakening or (2) interference through the 1-bit additional feedback of Table 5. According to one embodiment, the HARQ Nack and the indicator indicating the reason for the decoding failure may be composed of consecutive N-bits (where N is a natural number greater than or equal to 2). According to one embodiment, the HARQ Nack and the indicator indicating the reason for the decoding failure may each be set and / or transmitted independently. According to one embodiment, the indicator indicating the reason for the decoding failure may be set and / or transmitted independently of the HARQ Nack through RRC signaling, MAC CE, or pre-agreed signaling.

[0255] [Table 5] 1-bit additional feedback method

[0256]

[0257] Referring to Table 5, when the 1-bit additional feedback is set to "0", the base station (1301) can detect that a Nack has occurred due to a drop in electric field in addition to the Nack of the terminal (1303), and can perform an operation to increase the electric field of the terminal. According to one embodiment, the base station (1301) can perform an operation to enable the terminal (1303) to receive a signal when the electric field is weak, such as increasing the electric field of the terminal (1303) through cooperative transmission with another cell, preparing to trigger a handover procedure, or transmitting data to another carrier.

[0258] Referring to Table 5, when the 1-bit additional feedback is set to "1", the base station (1301) can determine that a Nack caused by interference has occurred in addition to the Nack of the terminal (1303) and can perform operations for interference control of the terminal (1303). According to one embodiment, the base station (1301) may consider operations such as causing the terminal (1303) to transmit a Sounding Reference Signal (SRS) for channel estimation for interference control of another cell, causing another cell to overhear the SRS and then use a nulling beam, changing the starting RB to prevent interference from another cell from entering, or changing the scheduling time between two cells.

[0259] According to one embodiment, the terminal (1303) can inform the base station (1301) whether the reason for the decoding failure is (1) electric field weakening or (2) interference through the 2-bit additional feedback of Table 6.

[0260] [Table 6] 2 bits additional feedback method

[0261]

[0262] Referring to Table 6, if the 2-bit additional feedback is set to "00" or "01", the base station (1301) can confirm that a Nack has occurred due to a drop in electric field in addition to the Nack of the terminal (1303), and can perform an operation to increase the electric field of the terminal (1303). According to one embodiment, the base station (1301) can perform an operation to enable the terminal (1603) to receive a signal when the electric field is weak, such as increasing the electric field of the terminal (1303) through cooperative transmission with another cell, preparing to trigger a handover procedure, or transmitting data to another carrier.

[0263] Referring to Table 6, if the 2-bit additional feedback is set to "01" or "11", the base station (1301) can confirm that an interference-induced Nack has occurred in addition to the Nack of the terminal (1303) and perform an operation for interference control of the terminal (1303). According to one embodiment, the base station (1301) may consider operations such as transmitting an SRS to the terminal (1303) for channel estimation for interference control of another cell, causing the other cell to overhear the SRS and then use a nulling beam, changing the start RB so that interference from another cell does not enter, or changing the scheduling time between the two cells.

[0264] Referring to Table 6, when the 2-bit additional feedback is set to "10", the base station (1301) can confirm that the interference and electric field are normal conditions in addition to the Nack of the terminal (1303), determine that the received signal has dropped due to temporary fading of the terminal, or perform other pre-set operations.

[0265] According to one embodiment, the determination of a decoding failure due to electric field weakening of the terminal (1303) can be inferred through the following operation. The terminal (1303) can measure the RSRP for the DMRS during the reception process. At this time, if the magnitude of the RSRP of the DMRS is lower than a preset threshold value (Th) or lower than the RSRP required to decode the assigned MCS, the terminal (1303) may consider this as a decoding failure due to electric field weakening.

[0266] According to one embodiment, the determination of a decoding failure due to interference of the terminal (1303) can be inferred through the following operation. The terminal (1303) can measure the RSRP for the DMRS during the reception process. Additionally, the terminal (1303) can calculate the reception SINR for the corresponding PDSCH block. At this time, if the terminal (1303) determines that the RSRP of the channel it experienced is sufficient to decode the corresponding MCS but the SINR is low, the terminal (1303) can determine that the corresponding TB failed to decode due to interference.

[0267] According to one embodiment, when performing a CBG-based HARQ operation, bits may be added to the codebook of the CBG. For example, if the codebook of the CBG is 8 bits, XXXXXXXXY or XXXXXXXXYY may be transmitted by adding an additional 1 bit of feedback (Y) or 2 bits of feedback (YY) to the codebook XXXXXXXX of the CBG. In this case, X and Y represent placeholders for the 1-bit feedback, and their values ​​are set to 0 or 1, and each X and each Y may have different values.

[0268] (Example 5) Preset method for reporting interference or electric field weakening

[0269] FIG. 14 illustrates an example of a pre-configuration method between a base station and a terminal for reporting interference or electric field weakening according to one embodiment of the present disclosure.

[0270] Referring to FIG. 14, in operation 1410, the terminal (1403) can transmit terminal capability information (UE capability) regarding interference or electric field weakening reports to the base station (1401). According to one embodiment, the terminal (1403) can transmit terminal capability information (UE capability) to the base station (1401) indicating that interference and the magnitude of the received signal can be measured individually upon PDSCH reception, or that SINR and SNR can be measured separately.

[0271] In operation 1420, the base station (1401) can transmit configuration information for reporting interference or field weakness to the terminal (1403). According to one embodiment, the base station (1401) can transmit configuration information for reporting interference or field weakness to the terminal (1403) via RRC signaling. According to one embodiment, the base station (1401) can transmit configuration information for reporting interference or field weakness to the terminal (1403) via MAC CE.

[0272] According to one embodiment, the base station (1401) may transmit configuration information to the terminal (1403) including at least one of a criterion for reporting that the magnitude of interference is large or a criterion for reporting that the electric field is weak. According to one embodiment, the base station (1401) may transmit configuration information to the terminal (1403) instructing to report that the interference is large when the magnitude of interference is x dB or more relative to the noise level, and instructing to report that the electric field is weak when the magnitude of the received signal is x dB or less relative to the noise level.

[0273] The base station (1401) starts a timer after transmitting configuration information for reporting interference or field weakness, and when the timer expires, it can perform an interference or field weakness reporting operation in the 1430 operation.

[0274] The terminal (1403) starts a timer after receiving setting information for interference or field weakening reporting, and when the timer expires, it can perform an interference or field weakening reporting operation in the 1440 operation.

[0275] FIG. 15 illustrates another example of a pre-configured method between a base station and a terminal for reporting interference or electric field weakening according to one embodiment of the present disclosure.

[0276] Referring to FIG. 15, in operation 1510, the base station (1501) may include an indicator in the DCI that instructs the terminal (1503) to perform an operation corresponding to an interference or field weakening report when assigning a PDSCH to the DCI. According to one embodiment, the indicator may be implemented as 1 bit (or 2 bits) to indicate whether the operation corresponding to an interference or field weakening report is in an on / off state.

[0277] In operation 1520, the terminal (1503) can perform an operation in response to the aforementioned interference or electric field weakening report during PDSCH decoding.

[0278] According to one embodiment, if the base station (1501) indicates through the DCI that the operation corresponding to interference or field weakening reporting is on, but the base station (1501) has not previously transmitted setting information for interference or field weakening reporting, the terminal (1503) can perform the operation of interference or field weakening reporting using a default value.

[0279] According to one embodiment, even if the base station (1501) does not specify an operation corresponding to interference or field weakness reporting as a DCI, if it was previously configured for interference or field weakness reporting, it may perform an operation corresponding to interference or field weakness reporting on a HARQ resource configured as a DCI. Alternatively, the base station (1501) may notify the terminal (1503) that it will not perform an operation corresponding to interference or field weakness reporting when assigning a PDSCH as a DCI.

[0280] FIG. 16 illustrates another example of a pre-configured method between a base station and a terminal for reporting interference or electric field weakening according to one embodiment of the present disclosure.

[0281] Referring to FIG. 16, in operation 1610, the base station (1601) may include an indicator in the DCI that instructs the terminal (1603) not to perform an operation corresponding to an interference or field weakening report when assigning a PDSCH to the DCI.

[0282] In operation 1620, the terminal (1603) can perform PDSCH decoding.

[0283] (Example 6) Interference Type Report

[0284] FIG. 17 is a flowchart illustrating a method for reporting interference types of a terminal according to one embodiment of the present disclosure.

[0285] Referring to FIG. 17, in operation 1710, the base station (1701) can transmit DCI to the terminal (1703) via PDCCH and transmit data to the terminal (1703) via PDSCH.

[0286] In operation 1720, the terminal (1703) can attempt PDSCH decoding based on the DCI received via PDCCH. After receiving the DCI, the terminal (1703) can receive data via PDSCH.

[0287] In operation 1730, the terminal (1703) can determine whether the type of interference is narrowband interference or wideband interference from at least one of DMRS RSRP, decoding SINR, and CRS (Cell-specific Reference Signal) when a NACK occurs while performing PDSCH decoding.

[0288] In operation 1740, the terminal (1703) can generate Nack feedback for HARQ operation and an indicator indicating whether the type of interference is narrowband interference or broadband interference. In operation 1750, the terminal (1703) can transmit the Nack feedback and the indicator indicating whether the type of interference is narrowband interference or broadband interference to the base station (1701).

[0289] The terminal (1703) can determine whether the situation is a narrowband interference situation or a broadband interference situation when reception fails due to interference. According to one embodiment, the terminal (1703) can determine that narrowband interference has occurred if reception fails for a certain number of CGs (cell groups) or less, even though the size of the received signal is sufficiently large. According to one embodiment, the terminal (1703) can determine that broadband interference has occurred if reception fails for a certain number of CGs or more, even though the size of the received signal is sufficiently large. According to one embodiment, the terminal (1703) can check how many CBs have received a NACK during the PDSCH decoding process, and when PDSCH decoding fails, it can check whether (1) a NACK has occurred for a certain number of CBs or more, or (2) a NACK has occurred for a certain number of CBs or less.

[0290] In operation 1360, the base station (1701) can perform the required operation based on HARQ-based retransmission and an indicator indicating whether the type of interference is narrowband interference or broadband interference.

[0291] According to one embodiment, the terminal (1710) may transmit an additional 1-bit feedback to the base station (1720) in addition to the HARQ as shown in Table 7 to inform the base station (1720) whether the type of interference is (1) broadband interference (e.g., caused by heavy BO processing of an adjacent cell) or (2) narrowband interference (e.g., caused by short BO processing of an adjacent cell). According to one embodiment, the HARQ Nack and the interference type indicator may consist of consecutive N-bits (where N is a natural number greater than or equal to 2). According to one embodiment, the HARQ Nack and the interference type indicator may each be set and / or transmitted independently. According to one embodiment, the interference type indicator may be set and / or transmitted independently of the HARQ Nack through RRC signaling, MAC CE, or pre-agreed signaling.

[0292] [Table 7] 1 bit additional feedback method

[0293]

[0294] Referring to Table 7, if the 1 bit additional feedback is "0", the base station (1701) can see that a Nack caused by narrowband interference has occurred in addition to the Nack of the terminal (1703). The base station (1701) can perform operations for narrowband interference control in cooperation with adjacent cells. According to one embodiment, the base station (1701) can perform operations to enable the terminal (1703) to receive signals more effectively, such as increasing the electric field of the terminal (1703) through cooperative transmission with other cells, preparing to trigger a handover procedure, or transmitting data to another sCell.

[0295] Referring to Table 7, if the 1 bit additional feedback is "1", the base station (1701) can see that a Nack caused by broadband interference has occurred in addition to the Nack of the terminal (1703). The base station (1701) can perform operations for broadband interference control in cooperation with adjacent cells. According to one embodiment, the base station (1701) can perform operations to enable the terminal (1703) to receive signals more effectively, such as increasing the electric field of the terminal (1703) through cooperative transmission with other cells, preparing to trigger a handover procedure, or transmitting data to another sCell.

[0296] According to one embodiment, when performing a CBG-based HARQ operation, bits may be added to the codebook of the CBG. For example, if the codebook of the CBG is 8 bits, XXXXXXXXY or XXXXXXXXYY may be transmitted by adding an additional 1 bit of feedback (Y) or 2 bits of feedback (YY) according to the embodiment to the codebook XXXXXXXX of the CBG. In this case, X and Y represent placeholders for the 1-bit feedback, and their values ​​are set to 0 or 1, and each X and each Y may have different values.

[0297] (Example 7) Setting up preset information for interference type reporting operation

[0298] FIG. 18 illustrates an example of a preset method between a base station and a terminal for interference type reporting according to one embodiment of the present disclosure.

[0299] Referring to FIG. 18, in operation 1810, the terminal (1803) can transmit terminal capability information (UE capability) regarding interference type reporting to the base station (1801). According to one embodiment, the terminal (1803) can transmit capability information (UE capability) to the base station (1801) indicating that it can determine that a specific CB has failed to receive by performing decoding for each PDSCH receiving CB. According to one embodiment, the terminal (1803) can transmit capability information (UE capability) to the base station (1801) indicating that if reception fails across multiple CBs for a specific frequency band, it can determine that the reception failure is due to interference for that frequency band.

[0300] In operation 1820, the base station (1801) can transmit configuration information for interference type reporting to the terminal (1803). According to one embodiment, the base station (1801) can transmit the interference type report to the terminal (1803) via RRC signaling. According to one embodiment, the base station (1801) can transmit the interference type report to the terminal (1803) via MAC CE.

[0301] According to one embodiment, the base station (1801) may transmit configuration information to the terminal (1803) including information regarding the definition of narrowband interference and / or broadband interference. According to one embodiment, the base station (1801) may define whether to consider the interference as narrowband interference when fewer than a certain number of RBs or fewer than a certain number of CBs fail to receive in RB units or RBG units. According to one embodiment, the base station (1801) may define whether to consider the interference as broadband interference when more than a certain number of RBs or more than a certain number of CBs fail to receive in RB units or RBG units.

[0302] The base station (1801) starts a timer after transmitting configuration information for interference type reporting, and when the timer expires, it can perform an interference type reporting operation in operation 1830. The terminal (1803) starts a timer after receiving configuration information for interference type reporting, and when the timer expires, it can perform an interference type reporting operation in operation 1840.

[0303] FIG. 19 illustrates another example of a preset method between a base station and a terminal for interference type reporting according to one embodiment of the present disclosure.

[0304] Referring to FIG. 19, in operation 1910, the base station (1901) may include an indicator in the DCI that instructs the terminal (1903) to perform an operation corresponding to an interference type report when assigning a PDSCH to the DCI. According to one embodiment, the indicator may be implemented as 1 bit (or 2 bits) to indicate whether the operation corresponding to an interference type report is in an on / off state.

[0305] In operation 1920, the terminal (1903) can perform an operation based on the interference type report during PDSCH decoding.

[0306] According to one embodiment, if the base station (1901) indicates through the DCI that the operation corresponding to the interference type report is on, but the base station (1901) has not previously transmitted the configuration information for the interference type report, the terminal (1903) can perform the interference type report operation using a default value.

[0307] According to one embodiment, even if the base station (1901) does not specify an operation corresponding to interference type reporting with DCI, if it was previously configured for interference type reporting, it may perform an operation for interference type reporting on a HARQ resource configured with DCI. Alternatively, the base station (1901) may notify the terminal (1903) that it will not perform an operation corresponding to interference type reporting when assigning PDSCH with DCI.

[0308] FIG. 20 illustrates another example of a preset method between a base station and a terminal for interference type reporting according to one embodiment of the present disclosure.

[0309] Referring to FIG. 20, in operation 2010, the base station (2001) may include an indicator in the DCI that instructs the terminal (2003) not to perform an operation corresponding to an interference type report when assigning PDSCH to the DCI.

[0310] In operation 2020, the terminal (2003) can perform PDSCH decoding.

[0311] FIG. 21 is a block diagram illustrating a terminal according to embodiments of the present disclosure.

[0312] The terminal (or UE) of FIG. 21 may be implemented as a UE or terminal illustrated in FIG. 1 to FIG. 20. Referring to FIG. 21, the terminal may include a transceiver (2110), a memory (2120), and a control unit (2130).

[0313] The transceiver (2110) can transmit and receive signals with a base station, a network device, or another terminal. The transceiver (2110) may also be referred to as a transceiver. The transceiver (2110) may include a transmitter and a receiver.

[0314] The memory (2120) can store at least one of the information transmitted and received through the transmission and reception unit (2110) and the information generated through the control unit (2130).

[0315] The control unit (2130) may be defined as a circuit or application-specific integrated circuit or at least one processor. The control unit (2130) may control the overall operation of the UE or terminal according to the embodiments proposed in this disclosure. For example, the control unit (2130) may control the signal flow between each block to perform operations according to the flowchart described above. Specifically, the control unit (2130) may control the operation of the UE or terminal illustrated in FIGS. 1 to 20, for example.

[0316] According to one embodiment, the control unit (2130) may receive downlink control information (DCI) from the base station via a physical downlink control channel (PDCCH). According to one embodiment, the control unit (2130) may decode data received from the base station via a physical downlink shared channel (PDSCH) based on the DCI. According to one embodiment, the control unit (2130) may generate information necessary for interference control or link adaptation of the base station based on the decoding result of the data received via the PDSCH. According to one embodiment, the control unit (2130) may control the transmission of information necessary for interference control or link adaptation of the base station to the base station, along with HARQ (hybrid automatic repeat request) feedback indicating whether the decoding of the data was successful.

[0317] According to one embodiment, the information required for interference control or link adaptation may include at least one of: information regarding the difference between a first SINR (signal to interference plus noise ratio) based on the decoding result and a second SINR corresponding to an MCS (modulation and coding scheme) assigned from the base station; the number of retransmissions required for successful decoding of the data; the type of interference experienced by the terminal; information indicating that decoding of the data fails due to interference; and information indicating that decoding of the data fails due to a drop in electric field.

[0318] According to one embodiment, information regarding the difference between the first SINR and the second SINR may indicate a comparison result between the difference value between the first SINR and the second SINR and at least one threshold value. According to one embodiment, the at least one threshold value may be set via radio resource control (RRC) signaling. According to one embodiment, the at least one threshold value may be set via a medium access control element (MAC CE). According to one embodiment, the at least one threshold value may be a preset value.

[0319] According to one embodiment, the control unit (2130) may transmit terminal capability information (UE capability) related to information required for interference control or link adaptation to the base station. According to one embodiment, the control unit (2130) may receive configuration information from the base station that includes at least one parameter required to generate information required for interference control or link adaptation.

[0320] According to one embodiment, in claim 1, the DCI may include an indicator for activating at least one piece of information included in the information required for interference control or link adaptation.

[0321] FIG. 22 is a block diagram illustrating a base station according to embodiments of the present disclosure.

[0322] The base station of FIG. 22 can be implemented as the base station, eNB, and gNB shown in FIG. 1 to 20. Referring to FIG. 22, the base station may include a transceiver (2210), a memory (2220), and a control unit (2230).

[0323] The transceiver (2210) can transmit and receive signals with a terminal, another base station, or a network device. The transceiver (2210) may also be referred to as a transceiver. The transceiver (2210) may include a transmitter and a receiver.

[0324] The memory (2220) can store at least one of the information transmitted and received through the transmission and reception unit (2210) and the information generated through the control unit (2230).

[0325] The control unit (2230) may be defined as a circuit or application-specific integrated circuit or at least one processor. The control unit (2230) can control the overall operation of the base station according to the embodiment proposed in this disclosure. For example, the control unit (2230) can control the signal flow between each block to perform operations according to the flowchart described above. Specifically, the control unit (2230) can control the operation of the base station, eNB, and gNB illustrated in FIGS. 1 to 20, for example.

[0326] According to one embodiment, the control unit (2230) may control the transmission of downlink control information (DCI) to user equipment (UE) via a physical downlink control channel (PDCCH). According to one embodiment, the control unit (2230) may control the transmission of data to the UE via a physical downlink shared channel (PDSCH). According to one embodiment, the control unit (2230) may receive information required for interference control or link adaptation of the base station from the UE, along with hybrid automatic repeat request (HARQ) feedback indicating whether decoding of the data was successful. The information required for interference control or link adaptation of the base station may be generated based on the decoding result of the data.

[0327] Methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software. When implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). One or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. One or more programs include instructions that cause the electronic device to execute the methods according to the embodiments described in the claims or specification of the present disclosure.

[0328] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, ROM (Read Only Memory), Electrically Erasable Programmable Read Only Memory (EEPROM), magnetic disc storage devices, Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs), or other forms of optical storage devices, magnetic cassettes. Alternatively, they may be stored in memory composed of some or all of these. Additionally, each constituent memory may include multiple units.

[0329] Additionally, the above program may be stored on an attachable storage device that can be accessed via a communication network such as the Internet, Intranet, Local Area Network (LAN), Wide LAN (WLAN), or Storage Area Network (SAN), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure through an external port. Additionally, a separate storage device on a communication network may be connected to a device performing an embodiment of the present disclosure.

[0330] In the specific embodiments of the present disclosure described above, the components included in the invention are expressed in a singular or plural form according to the specific embodiments presented. However, the singular or plural expression is selected to suit the situation presented for convenience of explanation, and the present disclosure is not limited to singular or plural components; even if a component is expressed in the plural, it may be composed of a singular form, and even if a component is expressed in the singular form, it may be composed of a plural form.

[0331] Meanwhile, although specific embodiments have been described in the detailed description of the present disclosure, it is understood that various modifications are possible within the scope of the present disclosure. Therefore, the scope of the present disclosure should not be limited to the described embodiments, but should be defined by the claims set forth below as well as equivalents thereof.

Claims

1. In a method of UE (user equipment) in a wireless communication system, A step of receiving DCI (downlink control information) from a base station via PDCCH (physical downlink control channel); Based on the above DCI, a step of decoding data received from the base station via the PDSCH (physical downlink shared channel); A step of generating information necessary for interference control or link adaptation of the base station based on the decoding result of the data received through the PDSCH; and A method characterized by including the step of transmitting information necessary for interference control or link adaptation of the base station to the base station, along with HARQ (hybrid automatic repeat request) feedback indicating whether decoding of the above data was successful.

2. In paragraph 1, the information required for the interference control or link adaptation is, Information regarding the difference between the first SINR (signal to interference plus noise ratio) according to the above decoding result and the second SINR corresponding to the MCS (modulation and coding scheme) assigned from the base station; Number of retransmissions required for successful decoding of the above data; The type of interference experienced by the above UE; Information indicating that decoding of the above data fails due to interference; and A method characterized by including at least one of the information indicating that decoding of the above data fails due to a drop in electric field.

3. In paragraph 2, the information regarding the difference between the first SINR and the second SINR is, A method characterized by indicating a comparison result between the difference value of the first SINR and the second SINR and at least one threshold value.

4. In Paragraph 3, The above at least one threshold value is set via RRC (radio resource control) signaling, or The above at least one threshold value is set via MAC CE (medium access control control element), or A method characterized in that at least one threshold value is a preset value.

5. In Paragraph 1, A step of transmitting terminal capability information (UE capability) related to information required for the above interference control or link adaptation to the base station; and A method characterized by further including the step of receiving from the base station configuration information including at least one parameter necessary to generate information required for the interference control or link adaptation.

6. In paragraph 1, the above DCI is, A method characterized by including an indicator for activating at least one piece of information included in the information required for the above interference control or link adaptation.

7. In the method of a base station in a wireless communication system, A step of transmitting DCI (downlink control information) to UE (user equipment) via PDCCH (physical downlink control channel); A step of transmitting data to the UE via PDSCH (physical downlink shared channel); and The method includes the step of receiving information necessary for interference control or link adaptation of the base station from the UE, along with HARQ (hybrid automatic repeat request) feedback indicating whether decoding of the above data was successful. A method characterized in that information required for interference control or link adaptation of the above base station is generated based on the decoding result of the above data.

8. In paragraph 7, the information required for the interference control or link adaptation is, Information regarding the difference between the first SINR (signal to interference plus noise ratio) according to the above decoding result and the second SINR corresponding to the MCS (modulation and coding scheme) assigned from the base station; Number of retransmissions required for successful decoding of the above data; The type of interference experienced by the above UE; Information indicating that decoding of the above data fails due to interference; and A method characterized by including at least one of the information indicating that decoding of the above data fails due to a drop in electric field.

9. In paragraph 8, the information regarding the difference between the first SINR and the second SINR is, A method characterized by indicating a comparison result between the difference value of the first SINR and the second SINR and at least one threshold value.

10. In Paragraph 9, The above at least one threshold value is set via RRC (radio resource control) signaling, or The above at least one threshold value is set via a MAC CE (medium access control control element), or A method characterized in that at least one threshold value is a preset value.

11. In Paragraph 7, A step of receiving terminal capability information (UE capability) related to information required for the above interference control or link adaptation from the UE; and A method characterized by further including the step of transmitting to the UE configuration information including at least one parameter necessary to generate information required for the interference control or link adaptation.

12. In Paragraph 7, the above DCI is, A method characterized by including an indicator for activating at least one piece of information included in the information required for the above interference control or link adaptation.

13. In a wireless communication system, regarding the UE (user equipment), Transmitter / receiver; and It includes a control unit, and the control unit is: Receive DCI (downlink control information) from the base station via PDCCH (physical downlink control channel), and Based on the above DCI, data received from the base station via the PDSCH (physical downlink shared channel) is decoded, and Based on the decoding result of the data received through the above PDSCH, information necessary for interference control or link adaptation of the base station is generated, and A UE characterized by controlling the transmission of information necessary for interference control or link adaptation of the base station to the base station, along with HARQ (hybrid automatic repeat request) feedback indicating whether decoding of the above data was successful.

14. In Paragraph 13, the information required for the interference control or link adaptation is, Information regarding the difference between the first SINR (signal to interference plus noise ratio) according to the above decoding result and the second SINR corresponding to the MCS (modulation and coding scheme) assigned from the base station; Number of retransmissions required for successful decoding of the above data; The type of interference experienced by the above UE; Information indicating that decoding of the above data fails due to interference; and A UE characterized by including at least one of the information indicating that decoding of the above data fails due to a drop in electric field.

15. In a base station of a wireless communication system, Transmitter / receiver; and It includes a control unit, and the control unit is: Controls the transmission of DCI (downlink control information) to UE (user equipment) via PDCCH (physical downlink control channel), and Controls the transmission of data to the UE via the PDSCH (physical downlink shared channel), and Along with HARQ (hybrid automatic repeat request) feedback indicating whether decoding of the above data was successful, information necessary for interference control or link adaptation of the base station is received from the UE, and A base station characterized by the fact that information required for interference control or link adaptation of the base station is generated based on the decoding result of the data.

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