Method, apparatus, and system for receiving downlink data and transmitting HARQ-ACK in a wireless communication system.

Abstract

This invention provides a method and apparatus for designing and transmitting a codebook that increases PUCCH coverage by reducing the amount of HARQ (Hybid Automatic Repeat Request)-ACK (acknowledgement) in situations where a downlink physical shared channel (PDSCH) or downlink physical control channel (PUCCH) is repeatedly transmitted across multiple slots. [Solution] A terminal used in a wireless communication system includes a communication module and a processor that controls the communication module, the processor receiving a plurality of first PDCCHs for downlink scheduling S23010, receiving a second PDCCH S23020, receiving a first PDSCH based on the first PDCCH S23030, receiving a second PDSCH based on the second PDCCH S23040, and transmitting a HARQ-ACK codebook for the first and second PDSCHs to the base station S23050.

Description

[Technical Field]

[0001] The present invention relates to a wireless communication system, and more specifically, to the transmission of downlink data and the corresponding acknowledgment in a wireless communication system. [Background technology]

[0002] 3GPP (registered trademark, same below) LTE(-A) defines uplink / downlink physical channels for transmitting physical layer signals. For example, physical channels such as the Physical Uplink Shared Channel (PUSCH), which transmits data on the uplink, the Physical Uplink Control Channel (PUCCH), which transmits control signals, and the Physical Random Access Channel (PRACH) are defined. On the downlink, there are channels such as the Physical Downlink Shared Channel (PDSCH), which transmits data, as well as the Physical Control Format Indicator Channel (PCFICH), Physical Downlink Control Channel (PDCCH), and Physical Hybrid ARQ Indicator Channel (PHICH), which transmit L1 / L2 control signals.

[0003] Of the aforementioned channels, the downlink control channel (PDCCH / EPDCCH) is a channel used by a base station to transmit uplink / downlink scheduling allocation control information, uplink transmit power control information, and other control information to one or more terminals. Because there are limitations on the resources that a base station can use for PDCCH transmission at one time, it is not possible to assign different resources to each terminal, and control information should be transmitted to any terminal by sharing resources. For example, in 3GPP LTE(-A), four REs (Resource Elements) are bundled to create a REG (Resource Element Group), which creates nine CCEs (Control Channel Elements). One or more CCEs are combined to inform terminals of the resources that can be sent, and many terminals share and use the CCEs. Here, the number of CCEs that are combined is called the CCE combination level, and the resources to which CCEs are allocated according to the possible CCE combination level is called the search space. There are two types of search spaces: a common search space defined for each base station and a terminal-specific or UE-specific search space defined for each terminal. The terminal decodes all possible CCE combinations in the search space and determines whether it matches its own PDCCH based on the user equipment (UE) identifier contained in the PDCCH. Therefore, such terminal operation inevitably involves a long decoding time for the PDCCH and consumes a lot of energy.

[0004] Following the commercialization of 4G communication systems, efforts are being made to develop improved 5G or pre-5G communication systems to meet the increasing demand for wireless data traffic. For this reason, 5G or pre-5G communication systems are referred to as Beyond 4G Network systems or Post LTE systems. To achieve high data transmission rates, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands (e.g., 60 GHz bands). To mitigate path loss in propagation and increase propagation distance in ultra-high frequency bands, beamforming, massive multiplexing-in-output (massive MIMO), full-dimensional multiplexing-in-output (FD-MIMO), array antennas, analog beamforming, and large-scale antenna technologies are being discussed for 5G communication systems. Furthermore, in order to improve the system network, 5G communication systems are undergoing technological development, including advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, moving networks, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation.In addition, 5G systems have seen the development of advanced coding modulation (ACM) methods such as FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), as well as advanced access technologies such as FBMC (Filter Bank Multi Carrier), NOMA (non-orthogonal multiple access), and SCMA (sparse code multiple access).

[0005] Meanwhile, the internet, a human-centered interconnected network where humans generate and consume information, is evolving into the Internet of Things (IoT) network, where distributed components such as objects exchange and process information. Internet of Everything (IoE) technology, which combines IoT technology with big data processing technologies via connections to cloud servers and other systems, is also emerging. To realize IoT, technological elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. Recently, technologies such as sensor networks for connecting objects, machine-to-machine (M2M), and machine-type communication (MTC) are being researched. In an IoT environment, intelligent IT services are provided that collect and analyze data generated from connected objects to create new value in human life. IoT, through the integration and combination of conventional IT technologies and various industries, is being applied to fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart home appliances, and advanced medical services.

[0006] Therefore, various attempts are being made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-to-machine communication, and MTC are being realized through 5G communication technologies such as beamforming, MIMO, and array antennas. As mentioned above, the application of cloud radio access networks (cloud RAN) as a big data processing technology can also be considered an example of the fusion of 5G technology and IoT technology. In general, mobile communication systems were developed to provide voice services while ensuring user activity.

[0007] Generally, mobile communication systems are developed to provide voice services while ensuring user activity. However, mobile communication systems have gradually expanded their service scope to include data services in addition to voice services, and have now developed to the point where they can provide high-speed data services. However, due to resource shortages and users' demand for even faster services, there is a need for more advanced mobile communication systems currently in service.

[0008] As mentioned above, future 5G technology will require lower latency data transmission due to the emergence of new applications such as real-time control and tactile internet, and the required latency for 5G data is expected to drop to 1 ms. 5G aims to provide data latency that is approximately 10 times lower than before. To solve this problem, 5G is expected to propose a communication system that utilizes mini-slots with even shorter TTI periods (e.g., 0.2 ms) in addition to conventional slots (or subframes).

[0009] Rel-16 enhanced URLLC (eURLLC) discusses various techniques to provide lower latency and higher reliability. Among them, to provide lower latency, it supports the transmission of uplink control channels containing two or more HARQ-ACKs within a single slot. Terminals can ensure lower latency by transmitting HARQ-ACKs as quickly as possible in response to successful reception of downlink shared channels. [Overview of the project] [Problems that the invention aims to solve]

[0010] The object of the present invention relates to a method for designing a semi-static HARQ-ACK codebook and a method for transmitting PUCCH in a 3GPP NR system, and provides a method and apparatus for solving problems that may arise in situations where PDSCH or PUCCH are repeatedly transmitted in multiple slots.

[0011] The technical problems that this invention aims to solve are not limited to those described above, and other technical problems not mentioned will be clearly understood by those with ordinary skill in the art to which this invention pertains from the following description. [Means for solving the problem]

[0012] A terminal of a wireless communication system according to an embodiment of the present invention includes a communication module and a processor that controls the communication mode. The processor receives a first PDCCH for scheduling a first Physical Downlink Shared Channel (PDSCH), the first PDCCH including a first counter downlink assignment indicator (DAI) indicating the number of PDSCHs scheduled up to the serving cell at the time the first PDCCH is monitored and a first total DAI indicating the total number of PDSCHs scheduled in the serving cell up to the time the PDCCH is monitored, and receives a second PDCCH for scheduling a second PDSCH, the second PDCCH including a second counter DAI and a second total DAI, receives the first PDCCH based on the first PDCCH, receives the second PDCCH based on the second PDCCH, and receives uplink control information including a HARQ-ACK codebook for the first PDSCH and the second PDSCH. Information (UCI) is transmitted to the base station, but if the number of bits in the first counter DAI and the number of bits in the second counter DAI are different, the value of the second counter DAI is determined based on the number of bits in the first counter DAI.

[0013] Furthermore, in the present invention, if the number of bits of the first counter DAI is smaller than the number of bits of the second counter DAI, the value indicated by the second counter DAI is determined based on at least one bit of the second counter DAI, in a number equal to the number of bits of the first counter DAI.

[0014] Furthermore, in the present invention, if there are multiple values ​​determined by at least one bit of the second counter DAI, the same number of bits as the first counter DAI, the value of the second counter DAI is determined to be the value among the multiple values ​​that has the smallest difference from the value indicated by the first counter DAI.

[0015] Furthermore, in the present invention, if the first counter DAI is 1 bit and the second counter DAI is 2 bits, the value of the second counter DAI is determined using either the LSB (Least Significant Bit) or the MSB (Most Significant Bit) of the 2 bits.

[0016] Furthermore, in the present invention, if one bit of the first counter DAI is "0", the value of the second counter DAI is determined to be "2" if the LSB or MSB of the second counter DAI is "0", and the value of the second counter DAI is determined to be "1" if the LSB or MSB of the second counter DAI is "1".

[0017] Furthermore, in the present invention, if one bit of the first counter DAI is "1", the value of the second counter DAI is determined to be "1" if the LSB or MSB of the second counter DAI is "1", and the value of the second counter DAI is determined to be "2" if the LSB or MSB of the second counter DAI is "0".

[0018] Furthermore, in the present invention, if the number of bits of the first counter DAI is greater than the number of bits of the second counter DAI, the value indicated by the second counter DAI is determined by extending the number of bits of the second counter DAI to the same number of bits as the number of bits of the first counter DAI.

[0019] Furthermore, in the present invention, if there are multiple values ​​for the second counter DAI that have been extended to the same number of bits as the first counter DAI, the value of the second counter DAI is determined to be the value among the multiple values ​​that has the smallest difference from the value indicated by the first counter DAI.

[0020] Furthermore, in the present invention, if the first counter DAI is 2 bits and the second counter DAI is 1 bit, the value of the second counter DAI is determined by expanding the 1 bit to 2 bits.

[0021] Furthermore, in the present invention, if two bits of the first counter DAI are "00" or "01" and one bit of the second counter DAI is "0", the second counter DAI is determined to be "3", and if two bits of the first counter DAI are "10" or "11" and one bit of the second counter DAI is "1", the second counter DAI is determined to be "1".

[0022] Furthermore, in the present invention, if two bits of the first counter DAI are "01" or "10" and one bit of the second counter DAI is "1", the second counter DAI is determined to be "4", and if two bits of the first counter DAI are "00" or "11" and one bit of the second counter DAI is "1", the second counter DAI is determined to be "2".

[0023] Furthermore, the present invention includes the steps of receiving a first PDCCH for scheduling a first Physical Downlink Shared Channel (PDSCH), the first PDCCH including a first counter downlink assignment indicator (DAI) indicating the number of PDSCHs scheduled up to the serving cell at the time the first PDCCH is monitored and a first total DAI indicating the total number of PDSCHs scheduled in the serving cell up to the time the PDCCH is monitored, receiving a second PDCCH for scheduling a second PDSCH, the second PDCCH including a second counter DAI and a second total DAI, receiving the first PDSCH based on the first PDCCH, receiving the second PDSCH based on the second PDCCH, and receiving uplink control information including a HARQ-ACK codebook for the first and second PDSCHs. The method includes the step of transmitting Information (UCI) to the base station, but if the number of bits of the first counter DAI and the number of bits of the second counter DAI are different, the value of the second counter DAI is determined based on the number of bits of the first counter DAI. [Effects of the Invention]

[0024] According to one embodiment of the present invention, a terminal transmits PUCCHs containing two or more HARQ-ACKs in a single slot. In this case, the coverage of PUCCHs can be increased by reducing the amount of HARQ-ACKs that each PUCCH may have.

[0025] Furthermore, according to one embodiment of the present invention, there is an effect in which HARQ-ACK information for PDSCHs scheduled by downlink control information having different formats is multiplexed and transmitted.

[0026] Furthermore, according to one embodiment of the present invention, HARQ-ACK information for PDSCHs scheduled by different downlink control information is multiplexed and transmitted, which has the effect of reducing the signaling overhead for transmitting HARQ-ACK information.

[0027] Furthermore, according to one embodiment of the present invention, a HARQ-ACK bit(s) sequence with low overhead of downlink control information (e.g., DCI) is determined, which has the effect of increasing the transmission efficiency of the network between the base station and the terminal.

[0028] The effects obtained from the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those with ordinary skill in the art to which the present invention pertains from the following description. [Brief explanation of the drawing]

[0029] [Figure 1] This figure shows an example of a wireless frame structure used in wireless communication systems. [Figure 2] This figure shows an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system. [Figure 3] This diagram illustrates the physical channels used in 3GPP systems (e.g., NR) and typical signal transmission methods utilizing those physical channels. [Figure 4] This figure shows the SS / PBCH block for initial cell access in a 3GPP NR system. [Figure 5] This diagram shows the procedure for transmitting control information and control channels in a 3GPP NR system. [Figure 6] This diagram shows the CORESET through which PDCCH is transmitted in a 3GPP NR system. [Figure 7] This diagram shows how to configure the PDCCH search space in a 3GPP NR system. [Figure 8]This is a conceptual diagram explaining career integration. [Figure 9] This diagram illustrates terminal carrier communication and multi-carrier communication. [Figure 10] This figure shows an example where the cross-carrier scheduling technique is applied. [Figure 11] This is a block diagram showing the configuration of a terminal and a base station according to one embodiment of the present invention. [Figure 12] This flowchart shows an example of signaling between a terminal and a base station to which one embodiment of the present invention is applied. [Figure 13] This figure shows an example of a method for a terminal to count the number of PDSCHs transmitted from a base station based on a pseudo code applied to one embodiment of the present invention. [Figure 14] This figure shows an example of a method for transmitting HARQ-ACKs based on downlink control information having different formats, according to one embodiment of the present invention. [Figure 15] This figure shows another example of a method for transmitting HARQ-ACKs based on downlink control information having different formats, according to one embodiment of the present invention. [Figure 16] This figure shows an example of a method for transmitting HARQ-ACK based on downlink control information for uplink and downlink scheduling according to one embodiment of the present invention. [Figure 17] This figure shows an example of a downlink assignee indicator for each downlink control information detected from a monitoring occasion according to one embodiment of the present invention. [Figure 18] This figure shows an example of a method for transmitting HARQ-ACKs based on downlink control information having different formats, based on pseudocode according to one embodiment of the present invention. [Figure 19] This figure shows an example of a downlink assignment indicator for each downlink control information detected from a monitoring opportunity according to one embodiment of the present invention. [Figure 20] This figure shows an example of a method for transmitting a HARQ-ACK to a PDSCH based on the reception order of the PDCCH according to one embodiment of the present invention. [Figure 21] This figure shows an example of a method for transmitting a HARQ-ACK to a PDSCH using the time information of a PDSCH according to one embodiment of the present invention. [Figure 22] This figure shows an example of a method for transmitting a HARQ-ACK to a PDSCH using the HARQ process ID (or HARQ process number) of the PDCCH that schedules the PDSCH, according to one embodiment of the present invention. [Figure 23] This is a sequence diagram showing an example of the operation of a terminal for transmitting HARQ-ACK based on downlink information having different formats, according to one embodiment of the present invention. [Figure 24] This is a sequence diagram illustrating an example of base station operation for receiving HARQ-ACKs based on downlink information having different formats, according to one embodiment of the present invention. [Modes for carrying out the invention]

[0030] The terminology used herein has been selected to be as widely used and general as possible, taking into account the function of the present invention; however, this may vary depending on the intentions, conventions, or emergence of new technologies of the articulate. In some cases, the applicant has arbitrarily selected certain terms, in which case their meaning will be described in the relevant section of the invention description. Therefore, it should be made clear that the terminology used herein should not be merely names of terms, but should be analyzed based on the substantive meaning of the terms and the overall content of this specification.

[0031] Throughout the specification, when one configuration is said to be “connected” to another, this includes not only cases where they are “directly connected,” but also cases where they are “electrically connected” through other intermediate components. Furthermore, when a configuration is said to “include” a particular component, this means, unless otherwise stated, that it includes other components rather than excluding them. In addition, the limitations of “greater than” or “less than” a particular critical point may be appropriately replaced by “greater than” or “less than” depending on the embodiment.

[0032] The following technologies are used in a variety of wireless connectivity systems, including CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), and SC-FDMA (single carrier frequency division multiple access). CDMA is implemented using radio technology such as UTRA (Universal Terrestrial Radio Access) and CDMA2000. TDMA is implemented using radio technology such as GSM (Global System for Mobile communications) / GPRS (General Packet Radio Service) / EDGE (Enhanced Data Rates for GSM Evolution). OFDMA is implemented using radio technology such as IEEE802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE802-20, and E-UTRA (Evolved UTRA). UTRA is part of UMTS (Universal Mobile Telecommunication System). 3GPP LTE (Long term evolution) is part of E-UMTS (Evolved UMTS) which uses E-UTRA, and LTE-A (Advanced) is an advanced version of 3GPP LTE. 3GPP NR is a system designed separately from LTE / LTE-A, and is intended to support eMBB (enhanced Mobile Broadband), URLLC (Ultra-Reliable and Low Latency Communication), and mMTC (massive Machine Type Communication) services, which are requirements of IMT-2020. While this explanation will focus on 3GPP NR for clarity, the technical concept of this invention is not limited to this.

[0033] Unless otherwise specified herein, a base station may include a gNB (next generation node B) as defined in 3GPP NR. Also, unless otherwise specified, a terminal may include a UE (user equipment). To aid understanding the explanation below, each concept will be described in separate embodiments, although these embodiments may be used in combination with each other. In this disclosure, terminal configuration may mean configuration by the base station. Specifically, the base station may transmit channels or signals to the terminal to configure the operation of the terminal or the values ​​of parameters used in the wireless communication system.

[0034] Figure 1 shows an example of a wireless frame structure used in a wireless communication system.

[0035] Referring to Figure 1, a radio frame (or radio frame) used in a 3GPP NR system has a length of 10 ms (ΔfmaxNf / 100) * Tc). A radio frame consists of 10 subframes (SF) of equal size, where Δfmax = 480 * 10³ Hz, Nf = 4096, Tc = 1 / (Δfref * Nf,ref), Δfref = 15 * 10³ Hz, and Nf,ref = 2048. Each of the 10 subframes within a single frame is assigned a number from 0 to 9. Each subframe has a length of 1 ms and consists of one or more slots determined by the subcarrier spacing. More specifically, the subcarrier spacing usable in a 3GPP NR system is 15 * 2 μkHz, where μ is the subcarrier spacing configuration, with values ​​from 0 to 4. In other words, 15kHz, 30kHz, 60kHz, 120kHz, or 240kHz are used as subcarrier intervals. A 1ms subframe consists of 2μm slots, each with a length of 2-μms. The 2μm slots within a subframe are each assigned numbers from 0 to 2μ-1. Similarly, the slots within a radio frame are each assigned numbers from 0 to 10*2μ-1. Time resources are divided by at least one of the following: radio frame number (also called radio frame index), subframe number (also called subframe index), or slot number (or slot index).

[0036] Figure 2 shows an example of a downlink (DL) / uplink (UL) slot structure in a wireless communication system. In particular, Figure 2 shows the resource grid structure of a 3GPP NR system.

[0037] There is one resource grid per antenna port. Referring to Figure 2, a slot contains multiple OFDM symbols in the time domain and multiple resource blocks (RBs) in the frequency domain. An OFDM symbol also means a single symbol interval. Unless otherwise specified, OFDM symbols are simply referred to as symbols. Hereafter, in this specification, symbols include OFDM symbols, SC-FDMA symbols, DFTs-OFDM symbols, etc. Referring to Figure 2, the signal transmitted from each slot is represented by a resource grid consisting of Nsize, μgrid, x*NRBSC subcarriers and Nslotsymb OFDM symbols. Here, x=DL for a downlink resource grid and x=UL for an uplink resource grid. Nsize, μgrid, and x indicate the number of resource blocks (RBs) with a subcarrier spacing component μ (x is DL or UL), and Nslotsymb indicates the number of OFDM symbols in the slot. NRBSC is the number of subcarriers constituting one RB, where NRBSC=12. OFDM symbols are also known as CP-OFDM (cyclic prefix OFDM) symbols or DFT-S-OFDM (discrete Fourier transform spread OFDM) symbols, depending on the multiple access method.

[0038] The number of OFDM symbols in a single slot can vary depending on the length of the cyclic prefix (CP). For example, a normal CP may contain 14 OFDM symbols in a single slot, while an extended CP may contain 12 OFDM symbols in a single slot. In specific embodiments, extended CPs are used only with a subcarrier interval of 60 kHz. For the sake of explanation, Figure 2 illustrates a case where a single slot consists of 14 OFDM symbols, but the embodiments of the present invention can be applied in the same manner to slots with other numbers of OFDM symbols. Referring to Figure 2, each OFDM symbol contains N size, μgrid, and x*NRBSC subcarriers in the frequency domain. Subcarrier types are divided into data subcarriers for transmitting data, reference signal subcarriers for transmitting reference signals, and guard bands. The carrier frequency is also called the center frequency (fc).

[0039] A single RB is defined by NRBSC (e.g., 12) consecutive subcarriers in the frequency domain. Incidentally, a resource consisting of one OFDM symbol and one subcarrier is called a resource element (RE) or tone. Therefore, a single RB consists of Nslotsymb*NRBSC resource elements. Each resource element in the resource grid is uniquely defined by an index pair (k, l) in a single slot. k is an index given in the frequency domain from 0 to Nsize, μgrid, and x*NRBSC-1, and l is an index given in the time domain from 0 to Nslotsymb-1.

[0040] For a terminal to receive signals from a base station or transmit base station signals, the terminal's time / frequency synchronization must be synchronized with the base station's time / frequency synchronization. This is because, if the base station and the terminal are not synchronized, the terminal cannot determine the time and frequency parameters necessary to demodulate DL signals and transmit UL signals at the correct time.

[0041] Each symbol in a radio frame operating in TDD (time division duplex) or unpaired spectrum consists of at least one of the following: a downlink symbol (DL symbol), an uplink symbol (UL symbol), or a flexible symbol. In FDD (frequency division duplex) or paired spectrum, a radio frame operating on a downlink carrier consists of either a downlink symbol or a flexible symbol, while a radio frame operating on an uplink carrier consists of either an uplink symbol or a flexible symbol. Downlink symbols can be used for downlink transmission but not uplink transmission, and uplink symbols can be used for uplink transmission but not downlink transmission. The use of a flexible symbol in the downlink or uplink is determined by the signal.

[0042] Information regarding the type of each symbol, i.e., whether it is a downlink symbol, uplink symbol, or flexible symbol, consists of a cell-specific (or common) RRC signal. Additionally, information regarding the type of each symbol consists of a UE-specific (or dedicated) RRC signal. The base station uses the cell-specific RRC signal to indicate: i) the period of the cell-specific slot configuration; ii) the number of slots containing only downlink symbols from the beginning of the cell-specific slot configuration period; iii) the number of downlink symbols from the first symbol of the slot immediately following the downlink-only slot; iv) the number of slots containing only uplink symbols from the end of the cell-specific slot configuration period; and v) the number of uplink symbols from the last symbol of the slot immediately preceding the uplink-only slot. Here, a symbol that is neither an uplink nor a downlink symbol is a flexible symbol.

[0043] If the information regarding the symbol type consists of the UE-specific RRC signal, the base station signals, by means of the cell-specific RRC signal, whether the flexible symbol is a downlink symbol or an uplink symbol. At this time, the UE-specific RRC signal cannot change the downlink symbol or uplink symbol consisting of the cell-specific RRC signal to another symbol type. The UE-specific RRC signal signals, for each slot, the number of downlink symbols among the Nslotsymb symbols of the corresponding slot and the number of uplink symbols among the Nslotsymb symbols of the corresponding slot. At this time, the downlink symbols of the slot are continuously configured from the first symbol to the i-th symbol of the slot. Also, the uplink symbols of the slot are continuously configured from the j-th symbol to the last symbol of the slot (where i < j). In a slot, a symbol that is not configured as either an uplink symbol or a downlink symbol is a flexible symbol.

[0044] FIG. 3 is a diagram for explaining a physical channel used in a 3GPP system (e.g., NR) and a general signal transmission method using the corresponding physical channel.

[0045] If the terminal is powered on or newly enters a cell, the terminal performs an initial cell search operation S101. Specifically, the terminal synchronizes with the base station in the initial cell search. For this purpose, the terminal receives the primary synchronization signal (PSS) and the secondary synchronization signal (SSS) from the base station to synchronize with the base station and obtains information such as the cell index. Next, the terminal receives the physical broadcast channel from the base station and obtains the broadcast information within the cell.

[0046] After completing the initial cell search, the terminal receives the physical downlink shared channel (PDSCH) via the physical downlink control channel (PDCCH) and the information carried on the PDCCH, thereby obtaining more detailed system information than that acquired through the initial cell search (S102). Here, the system information transmitted to the terminal is the cell common system information necessary for the terminal to operate correctly in the physical layer of the RRC (Radio Resource Control, RRC), and is called remaining system information or system information block (SIB) 1.

[0047] When a terminal first connects to a base station, or when there are no radio resources for signal transmission (when the terminal is in RRC_IDLE mode), the terminal can perform a random access process to the base station (steps S103 to S106). First, the terminal transmits a preamble on the physical random access channel (PRACH) (S103), and can receive a response message for the preamble from the base station on the PDCCH and the corresponding PDSCH (S104). If the terminal receives a valid random access response message, the terminal transmits data including its identifier to the base station on the physical uplink shared channel (PUSCH) indicated by the uplink grant transmitted from the base station via the PDCCH (S105). Next, the terminal waits to receive a PDCCH as an instruction from the base station for collision resolution. When the terminal successfully receives a PDCCH with its identifier (S106), the random access process ends. During the random access process, the terminal can obtain terminal-specific system information necessary for the terminal to function correctly at the physical layer of the RRC layer. Once the terminal obtains terminal-specific system information at the RRC layer, the terminal enters RRC_CONNECTED mode.

[0048] The RRC layer is used for message generation and management for control between terminals and the Radio Access Network (RAN). Furthermore, base stations and terminals can use the RRC layer to broadcast cell system information necessary for all terminals within a cell, manage the transmission of paging messages, manage mobility and handover, report and control terminal measurements, and manage terminal capabilities and storage. Generally, the update of signals transmitted in the RRC layer (hereinafter referred to as RRC signals) is longer than the transmission time interval (TTI) in the physical layer, so RRC settings can be maintained without change over long periods.

[0049] After the above procedure, the terminal receives PDCCH / PDSCH S107 and transmits the physical uplink shared channel (PUSCH) / physical uplink control channel (PUCCH) S108 as a general uplink / downlink signal transmission procedure. In particular, the terminal receives downlink control information (DCI) via PDCCH. DCI includes control information such as resource allocation information for the terminal. Also, the format of DCI may differ depending on its intended use. Uplink control information (UCI) transmitted by the terminal to the base station via the uplink includes downlink / uplink ACK / NACK signals, CQI (channel quality indicator), PMI (precoding matrix index), RI (rank indicator), etc. Here, CQI, PMI, and RI are included in CSI (channel state information). In the case of a 3GPP NR system, the terminal transmits the above-mentioned HARQ-ACK and control information such as CSI via PUSCH and / or PUCCH.

[0050] Figure 4 shows the SS / PBCH block for initial cell access in a 3GPP NR system.

[0051] When a terminal is powered on or attempts to access a new cell, it acquires time and frequency synchronization with the cell and performs an initial cell discovery process. During the cell discovery process, the terminal detects the cell's physical cell identity (NcellID). To do this, the terminal receives synchronization signals from the base station, such as the primary synchronization signal (PSS) and secondary synchronization signal (SSS), to synchronize with the base station. At this time, the terminal acquires information such as the cell identifier (identity, ID).

[0052] Refer to Figure 4(a) for a more detailed explanation of the synchronization signal (SS). The synchronization signal is divided into PSS and SSS. PSS is used to obtain time-domain synchronization and / or frequency-domain synchronization, such as OFDM symbol synchronization and slot synchronization. SSS is used to obtain frame synchronization and cell group ID. Referring to Figure 4(a) and Table 1, an SS / PBCH block consists of 20 RBs (=240 subcarriers) consecutively on the frequency axis and 4 OFDM symbols consecutively on the time axis. In this case, within the SS / PBCH block, the PSS is transmitted via subcarriers 56-182 in the first OFDM symbol, and the SSS is transmitted via subcarriers 56-182 in the third OFDM symbol. Here, the lowest subcarrier index of the SS / PBCH block is assigned starting from 0. In the first OFDM symbol on which the PSS is transmitted, the base station does not transmit signals via the remaining subcarriers, i.e., subcarriers 0-55 and 183-239. Furthermore, in the third OFDM symbol in which the SSS is transmitted, the base station does not transmit signals via subcarriers 48-55 and 183-191. In the SS / PBCH block, the base station transmits the PBCH (physical broadcast channel) via the remaining REs excluding the aforementioned signals. [Table 1]

[0053] The SS generates a total of 1008 unique physical layer cell IDs through combinations of three PSSs and SSSs. More specifically, each physical layer cell ID is part of only one physical layer cell identifier group, and each group is grouped into 336 physical layer cell identifier groups, each containing three unique identifiers. Therefore, the physical layer cell ID NcellID=3N(1)ID+N(2)ID is uniquely defined by an index N(1)ID ranging from 0 to 335 that represents a physical layer cell identifier group, and an index N(2)ID ranging from 0 to 2 that represents a physical layer identifier within the physical layer cell identifier group. The terminal detects the PSS and identifies one of the three unique physical layer identifiers. The terminal also detects the SSS and identifies one of the 336 physical layer cell IDs associated with the physical layer identifier. In this case, the PSS sequence dPSS(n) is as follows.

[0054] dPSS(n) = 1 - 2x(m) m=(n+43N(2)ID) mod 127 0 ≤ n < 127

[0055] Here, x(i+7)=(x(i+4)+x(i)) mod 2, [x(6)x(5)x(4)x(3)x(2)x(1)x(0)]=[1110110] is given.

[0056] Furthermore, the sequence dSSS(n) for SSS is as follows:

[0057] dSSS(n)=[1-2x0((n+m0) mod 127][1-2xi((n+m1) mod 127] m0=15 floor(N(1)ID / 112)+5N(2)ID m1 = N(1)ID mod 112 0 ≤ n < 127

[0058] Here, x0(i+7)=(x0(i+4)+x0(i))mod 2 x1(i+7)=(x1(i+1)+x1(i))mod 2,

[0059] [x0(6)x0(5)x0(4)x0(3)x0(2)x0(1)x0(0)]=[0000001] and [x1(6)x1(5)x1(4)x1(3)x1(2)x1(1)x1(0)]=[0000001] are given.

[0060] A 10ms long wireless frame is divided into two 5ms long half-frames. Refer to Figure 4(b) to describe the slot in which the SS / PBCH block is transmitted within each half-frame. The slot in which the SS / PBCH block is transmitted is one of cases A, B, C, D, or E. In case A, the subcarrier spacing is 15kHz, and the start of the SS / PBCH block is at the {2, 8} + 14*n symbol. In this case, n=0, 1 at carrier frequencies below 3GHz. Also, n=0, 1, 2, 3 at carrier frequencies above 3GHz and below 6GHz. In case B, the subcarrier spacing is 30kHz, and the start of the SS / PBCH block is at the {4, 8, 16, 20} + 28*n symbol. In this case, n=0 at carrier frequencies below 3GHz. Also, n=0, 1 at carrier frequencies above 3GHz and below 6GHz. In Case C, the subcarrier spacing is 30 kHz, and the SS / PBCH block starts at the {2nd, 8th} + 14*nth symbol. In this case, for carrier frequencies below 3 GHz, n=0, 1. Also, for carrier frequencies above 3 GHz and below 6 GHz, n=0, 1, 2, 3. In Case D, the subcarrier spacing is 120 kHz, and the SS / PBCH block starts at the {4th, 8th, 16th, 20th} + 28*nth symbol. In this case, for carrier frequencies above 6 GHz, n=0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18. In Case E, the subcarrier spacing is 240 kHz, and the SS / PBCH block starts at the {8th, 12th, 16th, 20th, 32nd, 36th, 40th, 44th} + 56*nth symbol. In this case, at carrier frequencies of 6 GHz or higher, n = 0, 1, 2, 3, 5, 6, 7, 8.

[0061] Figure 5 shows the procedure for transmitting control information and control channels in a 3GPP NR system. Referring to Figure 5(a), the base station adds a CRC (cyclic redundancy check) masked (e.g., by XOR operation) with an RNTI (radio network temporary identifier) ​​to the control information (e.g., DCI) S202. The base station scrambles the CRC with an RNTI value determined according to the purpose / target of each piece of control information. A common RNTI used by one or more terminals includes at least one of the following: SI-RNTI (system information RNTI), P-RNTI (paging RNTI), RA-RNTI (random access RNTI), and TPC-RNTI (transmit power control RNTI). Furthermore, the terminal-specific RNTI includes at least one of the following: C-RNTI (cell temporary RNTI), CS-RNTI, or MCS-C-RNTI. Next, after the base station performs channel encoding (e.g., polar coding) in S204, it performs rate-matching in S206 to match the amount of resources used for PDCCH transmission. Next, the base station multiplexes the DCIs (etc.) based on the PDCCH structure of the CCE (control channel element) in S208. The base station also applies additional processes S210 to the multiplexed DCIs (etc.), such as scrambling, modulation (e.g., QPSK), and interleaving, before mapping them to the resources to be transmitted. A CCE is the basic resource unit for PDCCH, and one CCE consists of multiple (e.g., 6) REGs (resource element groups). One REG consists of multiple (e.g., 12) REs. The number of CCEs used for one PDCCH is defined as the aggregation level. The 3GPP NR system uses 1, 2, 4, 8, or 16 integrated levels.Figure 5(b) is a diagram relating to the CCE integration level and PDCCH multiplexing, showing the types of CCE integration levels used for a single PDCCH and the CCEs transmitted in the control domain thereunder.

[0062] Figure 6 shows the CORESET through which PDCCH is transmitted in a 3GPP NR system.

[0063] A CORESET is a time-frequency resource on which PDCCH, a control signal for a terminal, is transmitted. Furthermore, the search space, described later, is mapped to a single CORESET. Therefore, instead of monitoring the entire frequency band to receive PDCCH, the terminal monitors the CORESET and the designated time-frequency domain to decode the PDCCH mapped to the CORESET. A base station configures one or more CORESETs for each cell in the terminal. A CORESET consists of up to three consecutive symbols on the time axis. A CORESET also consists of six consecutive PRB units on the frequency axis. In the embodiment shown in Figure 5, CORESET#1 consists of consecutive PRBs, while CORESET#2 and CORESET#3 consist of discontinuous PRBs. A CORESET can be located at any symbol within a slot. For example, in the embodiment shown in Figure 5, CORESET#1 starts at the first symbol in the slot, CORESET#2 starts at the fifth symbol in the slot, and CORESET#9 starts at the ninth symbol in the slot.

[0064] Figure 7 shows how to configure the PDCCH search space in a 3GPP NR system.

[0065] To transmit PDCCH to a terminal, each CORESET has at least one search space. In embodiments of the present invention, the search space is a collection of all time-frequency resources (hereinafter referred to as PDCCH candidates) to which the terminal's PDCCH is transmitted. The search space includes a common search space that all 3GPP NR terminals should search in common, and a terminal-specific or UE-specific search space that a specific terminal should search. In the common search space, PDCCHs that all terminals in a cell belonging to the same base station are set to search in common are monitored. In addition, terminal-specific search spaces are set up individually for each terminal to monitor the PDCCH assigned to each terminal at different locations in the search space depending on the terminal. In the case of terminal-specific search spaces, due to the limited control area to which PDCCHs are assigned, the search spaces between terminals may be partially overlapping. Monitoring PDCCHs includes blind decoding of PDCCH candidates in the search space. If blind decoding is successful, it is expressed as the PDCCH being (successfully) detected / received. If blind decoding fails, it is expressed as the PDCCH not being detected / received, or not being successfully detected / received.

[0066] For the sake of explanation, a PDCCH scrambled with a group common (GC) RNTI already known by one or more terminals for the purpose of transmitting downlink control information to one or more terminals is referred to as a group common (GC) PDCCH or common PDCCH. Furthermore, a PDCCH scrambled with a terminal-specific RNTI already known by a specific terminal for the purpose of transmitting uplink scheduling information or downlink scheduling information to a specific terminal is referred to as a terminal-specific PDCCH. The common PDCCH is included in the common search space, and the terminal-specific PDCCH is included in either the common search space or the terminal-specific PDCCH.

[0067] The base station informs each terminal or group of terminals via the PDCCH about resource allocation information for the transmission channels PCH (paging channel) and DL-SCH (downlink-shared channel) (i.e., DL Grant), or information about UL-SCH resource allocation and HARQ (hybrid automatic repeat request) (i.e., UL Grant). The base station transmits PCH transmission blocks and DL-SCH transmission blocks via the PDSCH. The base station transmits data excluding specific control information or specific service data via the PDSCH. The terminal also receives data excluding specific control information or specific service data via the PDSCH.

[0068] The base station transmits the PDCCH containing information about which terminals (one or more terminals) the PDSCH data will be transmitted to and how those terminals should receive and decode the PDSCH data. For example, suppose a DCI transmitted via a specific PDCCH is CRC masked with an RNTI named "A", and that DCI indicates that the PDSCH is assigned to a radio resource (e.g., frequency location) named "B", and indicates transmission format information (e.g., transmission block size, modulation scheme, coding information, etc.) named "C". Terminals monitor the PDCCH using their own RNTI information. In this case, if a terminal blind-decodes the PDCCH using the "A" RNTI, that terminal will receive the PDCCH and, through the information of the received PDCCH, receive the PDSCH indicated by "B" and "C".

[0069] Table 2 shows one example of PUCCH used in a wireless communication system. [Table 2]

[0070] PUCCH is used to transmit the following uplink control information (UCI):

[0071] -SR (Scheduling Request): This is information used to request uplink UL-SCH resources.

[0072] -HARQ-ACK: A response to a PDCCH (indicating a DL SPS release) and / or to an uplink transmission block (TB) on a PDSCH. HARQ-ACK indicates whether information transmitted via the PDCCH or PDSCH has been received. HARQ-ACK responses include positive ACK (simply ACK), negative ACK (hereinafter NACK), DTX (Discontinuous Transmission), or NACK / DTX. Here, the term HARQ-ACK is used interchangeably with HARQ-ACK / NACK and ACK / NACK. Generally, ACK is represented by a bit value of 1 and NACK is represented by a bit value of 0.

[0073] -CSI: This is feedback information for the downlink channel. It is generated by the terminal based on the CSI-RS (Reference Signal) transmitted by the base station. MIMO (multiple input multiple output) related feedback information includes RI and PMI. CSI is divided into CSI Part 1 and CSI Part 2 depending on the information it indicates.

[0074] The 3GPP NR system uses five PUCCH formats to support diverse service scenarios, diverse channel environments, and frame structures.

[0075] PUCCH format 0 is a format for transmitting 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 0 is transmitted via one or two OFDM symbols on the time axis and one RB on the frequency axis. If PUCCH format 0 is transmitted via two OFDM symbols, the same sequence is transmitted for the two symbols with different RBs. Through this, the terminal obtains a frequency diversity gain. More specifically, the terminal determines the cyclic shift value mcs according to the Mbit bit UCI (Mbit=1 or 2), and maps the sequence obtained by cyclically shifting a base sequence of length 12 by the determined value mcs to 12 REs consisting of one OFDM symbol and one PRB, and transmits it. If the number of cyclic shifts available to the terminal is 12 and Mbit=1, then 1-bit UCI0 and 1 are represented by sequences corresponding to two cyclic shifts with a cyclic shift value difference of 6. Furthermore, if Mbit=2, the 2-bit UCI00, 01, 11, and 10 represent a sequence of four cyclic shifts where the difference in cyclic shift values ​​is 3.

[0076] PUCCH format 1 transmits 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 1 is transmitted via a continuous sequence of OFDM symbols on the time axis and a single PRB on the frequency axis. Here, the number of OFDM symbols occupied by PUCCH format 1 is one between 4 and 14. More specifically, a UCI with Mbit=1 is modulated with BPSK. The terminal modulates a UCI with Mbit=2 with QPSK (quadrature phase shift keying). A signal is obtained by multiplying the modulated complex valued symbol d(0) by a sequence of length 12. The terminal transmits the obtained signal by spreading it with a time-axis OCC (orthogonal cover code) to the even-numbered OFDM symbols assigned to PUCCH format 1. The maximum number of different terminals that can be multiplexed on the same RB in PUCCH format 1 is determined by the length of the OCC used. For odd-numbered OFDM symbols in PUCCH format 1, the DMRS (demodulation reference signal) is spread across the OCC and mapped to them.

[0077] PUCCH format 2 transmits UCI exceeding 2 bits. PUCCH format 2 is transmitted via one or two OFDM symbols on the time axis and one or more RBs on the frequency axis. If PUCCH format 2 is transmitted via two OFDM symbols, the same sequence is transmitted via the two OFDM symbols with different RBs. Through this, the terminal obtains frequency diversity gain. More specifically, an Mbit bit UCI (Mbit > 2) is bit-level scrambled and QPSK modulated and mapped to the RBs of one or two OFDM symbols, where the number of RBs is one between 1 and 16.

[0078] PUCCH format 3 or PUCCH format 4 transmits UCI exceeding 2 bits. PUCCH format 3 or PUCCH format 4 is transmitted via continuous OFDM symbols on the time axis and one PRB on the frequency axis. The number of OFDM symbols occupied by PUCCH format 3 or PUCCH format 4 is one of 4 to 14. Specifically, the terminal modulates an Mbit bit UCI (Mbit > 2) with π / 2-BPSK (Binary Phase Shift Keying) or QPSK to generate complex number symbols d(0) to d(Msymb-1). Here, with π / 2-BPSK, Msymb = Mbit, and with QPSK, Msymb = Mbit / 2. The terminal does not apply block-unit spreading to PUCCH format 3. However, the terminal may apply block-unit spreading to one RB (i.e., 12 subcarriers) using a PreDFT-OCC of length -12 so that the PUCCH format 4 has two or four multiplexing capacities. The terminal transmits the spread signal by transmitting precoding (or DFT-precoding) and mapping it to each RE.

[0079] In this case, the number of RBs occupied by PUCCH format 2, PUCCH format 3, or PUCCH format 4 is determined according to the length of the UCI transmitted by the terminal and the maximum code rate. If the terminal uses PUCCH format 2, it transmits both HARQ-ACK information and CSI information via PUCCH. If the number of RBs that the terminal can transmit is greater than the maximum number of RBs that PUCCH format 2, PUCCH format 3, or PUCCH format 4 can use, the terminal will not transmit some of the UCI information according to the priority of the UCI information, and will transmit only the remaining UCI information.

[0080] PUCCH format 1, PUCCH format 3, or PUCCH format 4 is configured via an RRC signal to instruct frequency hopping within a slot. When frequency hopping is configured, the index of the RB to be frequency-hopped is determined by the RRC signal. If PUCCH format 1, PUCCH format 3, or PUCCH format 4 is transmitted over N OFDM symbols in the time axis, the first hop will have floor(N / 2) OFDM symbols, the second hop will have ceil(N / 2) OFDM symbols.

[0081] PUCCH format 1, PUCCH format 3, or PUCCH format 4 are configured to be repeatedly transmitted to multiple slots. In this case, the number K of slots to which the PUCCH is repeatedly transmitted is determined by the RRC signal. The repeatedly transmitted PUCCH should start from the same OFDM symbol in the same position within each slot and have the same length. If any of the OFDM symbols in a slot to which the terminal is to transmit the PUCCH is indicated as a DL symbol by the RRC signal, the terminal does not transmit the PUCCH from that slot but postpones transmission to the next slot.

[0082] On the other hand, in the 3GPP NR system, terminals transmit and receive using a bandwidth smaller than or equal to the carrier (or cell) bandwidth. For this purpose, terminals are configured with a bandwidth part (BWP) consisting of a continuous portion of the carrier bandwidth. Terminals operating according to TDD or in the ampered spectrum have up to four DL / UL BWP pairs per carrier (or cell). The terminal also activates one DL / UL BWP pair. Terminals operating according to FDD or in the paired spectrum have up to four DL BWPs configured on the downlink carrier (or cell) and up to four UL BWPs configured on the uplink carrier (or cell). The terminal activates one DL BWP and one UL BWP per carrier (or cell). The terminal does not have to receive or transmit from time-frequency resources other than the activated BWPs. The activated BWPs are called active BWPs.

[0083] The base station refers to the activated BWP among the configured BWPs of a terminal as the DCI. The BWP indicated by the DCI is activated, and the other configured BWPs are deactivated. In a carrier (or cell) operating in TDD mode, the base station includes a BPI (bandwidth part indicator) in the DCI that schedules the PDSCH or PUSCH to indicate which BWP to activate in order to change the terminal's DL / UL BWP pair. The terminal receives the DCI that schedules the PDSCH or PUSCH and identifies the DL / UL BWP pair to activate based on the BPI. In the case of a downlink carrier (or cell) operating in FDD mode, the base station includes a BPI informing the DCI that schedules the PDSCH which BWP to activate in order to change the terminal's DL BWP. In the case of an uplink carrier (or cell) operating in FDD mode, the base station includes a BPI informing the DCI that schedules the PUSCH which BWP to activate in order to change the terminal's UL BWP.

[0084] Figure 8 is a conceptual diagram illustrating career integration.

[0085] Carrier aggregation refers to a method used by wireless communication systems to utilize a wider frequency band by having terminals use multiple frequency blocks, or (logical) cells, consisting of uplink resources (or component carriers) and / or downlink resources (or component carriers), within a single larger logical frequency band. For convenience of explanation, the term "component carrier" will be used consistently below.

[0086] Referring to Figure 8, as an example of a 3GPP NR system, the overall system bandwidth includes up to 16 component carriers, each component carrier having a bandwidth of up to 400 MHz. Each component carrier includes one or more physically consecutive subcarriers. Although Figure 8 shows each component carrier having the same bandwidth, this is merely illustrative, and each component carrier may have different bandwidths. Also, although each component carrier is shown as being adjacent to each other on the frequency axis, the diagram is a logical representation, and each component carrier may be physically adjacent to or far from each other.

[0087] Each component carrier uses a different center frequency. Furthermore, physically adjacent component carriers share a single common center frequency. In the embodiment shown in Figure 8, assuming all component carriers are physically adjacent, center frequency A is used for all component carriers. If we assume that the component carriers are not physically adjacent, then center frequencies A and B are used for each component carrier.

[0088] When the overall system bandwidth is expanded through carrier aggregation, the frequency band used for communication with each terminal is defined on a component carrier basis. Terminal A uses the overall system bandwidth of 100 MHz and communicates using all five component carriers. Terminals B1 to B5 use only a 20 MHz bandwidth and communicate using one component carrier each. Terminals C1 and C2 use only a 40 MHz bandwidth and communicate using two component carriers each. The two component carriers may be logically / physically adjacent or not. In the embodiment shown in Figure 8, terminal C1 uses two non-adjacent component carriers, and terminal C2 uses two adjacent component carriers.

[0089] Figure 9 is a diagram illustrating terminal carrier communication and multiple carrier communication. Specifically, Figure 9(a) shows the subframe structure of a single carrier, and Figure 9(b) shows the subframe structure of a multiple carrier.

[0090] Referring to Figure 9(a), a typical wireless communication system, in FDD mode, transmits or receives data via one DL band and its corresponding UL band. In other specific embodiments, in TDD mode, the wireless communication system divides the wireless frame into uplink time units and downlink time units in the time domain, and transmits or receives data via the uplink / downlink time units. Referring to Figure 9(b), three 20MHz component carriers (CCs) are aggregated in both the UL and DL bands, supporting a 60MHz bandwidth. Each CC is either adjacent or non-adjacent to the others in the frequency domain. For convenience, Figure 9(b) shows a symmetrical case where the bandwidths of the UL CCs and DL CCs are the same, but the bandwidths of each CC may be determined independently. Asymmetric carrier aggregations with different numbers of UL CCs and DL CCs are also possible. A DL / UL CC assigned / configured to a specific terminal via RRC is referred to as the serving DL / UL CC of that terminal.

[0091] A base station communicates with a terminal by activating some or all of the terminal's serving CCs, or by deactivating some of the CCs. The base station may change which CCs are activated / deactivated, or change the number of CCs that are activated / deactivated. Once a base station assigns available CCs to a terminal on a cell-specific or terminal-specific basis, at least one of the initially assigned CCs does not need to be deactivated unless the CC assignments for the terminal are completely reconfigured or the terminal is handed over. The CC that is not deactivated by the terminal is called the primary CC (PCC) or PCell (primary cell), and the CC that the base station can freely activate / deactivate is called the secondary CC (SCC) or SCell (secondary cell).

[0092] On the other hand, 3GPP NR uses the concept of a cell to manage radio resources. A cell is defined as a combination of downlink and uplink resources, i.e., a combination of DL CC and UL CC. A cell consists of DL resources alone, or a combination of DL and UL resources. If carrier aggregation is supported, the linkage between the carrier frequency of the DL resource (or DL ​​CC) and the carrier frequency of the UL resource (or UL CC) is indicated by system information. Carrier frequency refers to the center frequency of each cell or CC. A cell corresponding to a PCC is called a PCell, and a cell corresponding to an SCC is called a SCell. In the downlink, the carrier corresponding to a PCell is a DL PCC, and in the uplink, the carrier corresponding to a PCell is a UL PCC. Similarly, in the downlink, the carrier corresponding to a SCell is a DL SCC, and in the uplink, the carrier corresponding to a SCell is a UL SCC. Depending on the terminal capacity, a serving cell consists of one PCell and zero or more SCells. If the RRC_CONNECTED state exists but carrier aggregation is not configured, or if the UE does not support carrier aggregation, there will be only one serving cell consisting solely of PCells.

[0093] As described above, the term "cell" used in carrier aggregation is distinct from the term "cell" which refers to a specific geographical area where communication services are provided by a single base station or antenna group. However, in order to distinguish between a cell referring to a specific geographical area and a cell in carrier aggregation, in this invention, a cell in carrier aggregation is referred to as CC, and a cell referring to a geographical area is referred to as cell.

[0094] Figure 10 shows an example where the cross-carrier scheduling technique is applied. Once cross-carrier scheduling is set up, the control channel transmitted via the first CC uses the carrier indicator field (CIF) to schedule the data channel transmitted via the first or second CC. The CIF is contained within the DCI. In other words, a scheduling cell is set up, and DL grants / UL grants transmitted from the PDCCH region of the scheduling cell schedule the PDSCH / PUSCH of the scheduled cell. That is, the PDCCH region of the scheduling cell is a search area for multiple component carriers. A PCell is essentially a scheduling cell, and a specific SCell is designated as a scheduling cell by a higher hierarchy.

[0095] In the embodiment shown in Figure 10, we assume that three DL CCs are merged. Here, DL component carrier #0 is assumed to be a DL PCC (or PCell), and DL component carriers #1 and #2 are assumed to be DL SCCs (or SCells). We also assume that the DL PCC is configured as a PDCCH monitoring CC. If cross-carrier scheduling is not configured by terminal-specific (or terminal-group-specific, or cell-specific) higher-level signaling, the CIF will be disabled, and each DL CC will transmit only PDCCHs that schedule their own PDSCH without a CIF according to the NR PDCCH rules (non-cross-carrier scheduling, self-carrier scheduling). In contrast, if cross-carrier scheduling is configured through terminal-specific (or terminal-group-specific, or cell-specific) higher-level signaling, CIF becomes enabled, and a specific CC (e.g., DL PCC) uses CIF to transmit not only PDCCHs that schedule PDSCHs of DL CC A, but also PDCCHs that schedule PDSCHs of other CCs (cross-carrier scheduling). In contrast, other DL CCs do not transmit PDCCHs. Therefore, depending on whether cross-carrier scheduling is configured for the terminal, the terminal either monitors PDCCHs without CIFs and receives self-carrier scheduled PDSCHs, or monitors PDCCHs with CIFs and receives cross-carrier scheduled PDSCHs.

[0096] On the other hand, Figures 9 and 10 illustrate the subframe structure of a 3GPP LTE-A system, and the same or similar configurations are applicable to a 3GPP NR system. However, in a 3GPP NR system, the subframes in Figures 9 and 10 are switched to slots.

[0097] Figure 11 is a block diagram showing the configuration of a terminal and a base station according to one embodiment of the present invention. In one embodiment of the present invention, the terminal is embodied in various types of wireless communication devices or computing devices that ensure portability and mobility. The terminal is referred to as UE, STA (Station), MS (Mobile Subscriber), etc. In the embodiment of the present invention, the base station controls and manages cells (e.g., macrocells, femtocells, picocells, etc.) in the service area and performs functions such as signal transmission, channel assignment, channel monitoring, self-diagnosis, and relaying. The base station is referred to as gNB (next Generation NodeB) or AP (Access Point), etc.

[0098] As shown in the figure, a terminal 100 according to one embodiment of the present invention includes a processor 110, a communication module 120, a memory 130, a user interface unit 140, and a display unit 150.

[0099] First, the processor 110 executes various instructions or programs to process data inside the terminal 100. The processor 110 also controls the overall operation of the terminal 100, including each unit, and controls the transmission and reception of data between units. Here, the processor 110 is configured to perform the operations described in the embodiment of the present invention. For example, the processor 110 may receive slot configuration information, determine the slot configuration based on that information, and perform communication according to the determined slot configuration.

[0100] Next, the communication module 120 is an integrated module that performs wireless communication using a wireless communication network and wireless LAN access using a wireless LAN. To this end, the communication module 120 incorporates multiple network interface cards (NICs), such as cellular communication interface cards 121 and 122 and an unlicensed band communication interface card 123, either internally or externally. In the drawing, the communication module 120 is shown as an integrated module, but each network interface card may be arranged independently depending on the circuit configuration or application, contrary to the drawing.

[0101] The cellular communication interface card 121 transmits and receives radio signals to and from at least one of the base station 200, an external device, and a server via a mobile communication network, and provides cellular communication services in a first frequency band based on instructions from the processor 110. According to one embodiment, the cellular communication interface card 121 includes at least one NIC module that utilizes a frequency band of less than 6 GHz. At least one NIC module of the cellular communication interface card 121 independently performs cellular communication with at least one of the base station 200, an external device, and a server, depending on the cellular communication standard or protocol of the sub-6 GHz frequency band supported by the NIC module.

[0102] The cellular communication interface card 122 uses a mobile communication network to send and receive radio signals with at least one of the base station 200, an external device, or a server, and provides cellular communication services in the second frequency band based on instructions from the processor 110. In one embodiment, the cellular communication interface card 122 includes at least one NIC module that utilizes a frequency band of 6 GHz or higher. At least one NIC module of the cellular communication interface card 122 independently performs cellular communication with at least one of the base station 200, an external device, or a server, according to the cellular communication standard or protocol of the 6 GHz or higher frequency band supported by the NIC module.

[0103] The unlicensed band communication interface card 123 transmits and receives radio signals to and from at least one of the base station 200, an external device, or a server via the third frequency band, which is an unlicensed band, and provides communication services in the unlicensed band based on instructions from the processor 110. The unlicensed band communication interface card 123 includes at least one NIC module that utilizes the unlicensed band. For example, the unlicensed band may be a 2.4 GHz or 52.6 GHz band. At least one NIC module of the unlicensed band communication interface card 123 independently or dependently performs cellular communication with at least one of the base station 200, an external device, or a server, depending on the unlicensed band communication standard or protocol of the frequency band supported by the NIC module.

[0104] Next, the memory 130 stores control programs used by the terminal 100 and various data associated with them. Such control programs include predetermined programs necessary for the terminal 100 to communicate wirelessly with at least one of the following: a base station 200, an external device, or a server.

[0105] Next, the user interface 140 includes various forms of input / output means provided in the terminal 100. In other words, the user interface unit 140 receives user input using various input means, and the processor 110 controls the terminal 100 based on the received user input. The user interface 140 also outputs based on instructions from the processor 110 using various output means.

[0106] Next, the display unit 150 outputs various images to the display screen. The display unit 150 outputs various display objects, such as content generated by the processor 110 or user interfaces based on control instructions from the processor 110.

[0107] Furthermore, the base station 200 according to the embodiment of the present invention includes a processor 210, a communication module 220, and a memory 230.

[0108] First, the processor 210 executes various instructions or programs to process data within the base station 200. The processor 210 also controls the overall operation of the base station 200, including each unit, and controls the transmission and reception of data between units. Here, the processor 210 is configured to perform the operations described in the embodiment of the present invention. For example, the processor 210 may signal slot configuration information and perform communication according to the signaled slot configuration.

[0109] Next, the communication module 220 is an integrated module that performs wireless communication using a wireless communication network and wireless LAN access using a wireless LAN. To this end, the communication module 220 incorporates multiple network interface cards, such as cellular communication interface cards 221 and 222, and an unlicensed band communication interface card 223, either internally or externally. In the drawings, the communication module 220 is shown as an integrated module, but each network interface card may be arranged independently depending on the circuit configuration or application, contrary to the drawings.

[0110] The cellular communication interface card 221 transmits and receives wireless signals to and from at least one of the terminal 100, external devices, and servers described above using a mobile communication network, and provides cellular communication services in the first frequency band based on instructions from the processor 210. According to one embodiment, the cellular communication interface card 221 includes at least one NIC module that utilizes a frequency band of less than 6 GHz. At least one NIC module of the cellular communication interface card 221 independently performs cellular communication with at least one of the terminal 100, external devices, and servers, according to the cellular communication standard or protocol of the frequency band of less than 6 GHz supported by the NIC module.

[0111] The cellular communication interface card 222 uses a mobile communication network to send and receive wireless signals to and from at least one of the terminal 100, an external device, and a server, and provides cellular communication services in the second frequency band based on instructions from the processor 210. In one embodiment, the cellular communication interface card 222 includes at least one NIC module that utilizes a frequency band of 6 GHz or higher. At least one NIC module of the cellular communication interface card 222 independently performs cellular communication with at least one of the terminal 100, an external device, and a server, according to the cellular communication standard or protocol of the 6 GHz or higher frequency band supported by the NIC module.

[0112] The unlicensed band communication interface card 223 uses the third frequency band, which is an unlicensed band, to send and receive wireless signals with at least one of the terminal 100, an external device, or a server, and provides communication services in the unlicensed band based on instructions from the processor 210. The unlicensed band communication interface card 223 includes at least one NIC module that utilizes the unlicensed band. For example, the unlicensed band may be the 2.4GHz or 52.6GHz band. At least one NIC module of the unlicensed band communication interface card 223 independently or dependently performs cellular communication with at least one of the terminal 100, an external device, or a server, depending on the unlicensed band communication standard or protocol of the frequency band supported by the NIC module.

[0113] The terminal 100 and base station 200 shown in Figure 11 are block diagrams according to one embodiment of the present invention, and the separately shown blocks represent logically distinguished elements of the device. Therefore, the above-mentioned elements of the device are mounted on one or more chips depending on the device design. Furthermore, some components of the terminal 100, such as the user interface unit 150 and the display unit 150, may be selectively provided in the terminal 100. In addition, the user interface 140 and the display unit 150 may be additionally provided in the base station 200 as needed.

[0114] In an NR radio communication system, a terminal transmits a codebook containing hybrid automatic repeat request (HARQ)-ACK information to signal the success or failure of receiving a downlink signal or channel. A HARQ-ACK codebook contains one or more bits indicating the success or failure of receiving a downlink channel or signal. Here, the downlink channel includes at least one of the following: a physical downlink shared channel (PDSCH), a semi-persistence scheduling (SPS) PDSCH, and a PDCCH that releases an SPS PDSCH. HARQ-ACK codebooks are classified into semi-static HARQ-ACK codebooks (or the first type of codebook) and dynamic HARQ-ACK codebooks (or the second type of coding). The base station configures one of the two HARQ-ACK codebooks on the terminal. The terminal uses the HARQ-ACK codebook configured on it.

[0115] When a semi-static HARQ-ACK codebook is used, the base station uses the RRC signal to set the number of bits in the HARQ-ACK codebook and the information that determines whether each bit of the HARQ-ACK codebook is successfully received for which downlink signal or channel. Therefore, the base station does not need to signal the terminal with the information necessary for transmitting the HARQ-ACK codebook each time it is needed.

[0116] When a dynamic HARQ-ACK codebook is used, the base station signals the information necessary to generate the HARQ-ACK codebook via the PDCCH (or DCI). Specifically, the base station signals the information necessary to generate the HARQ-ACK codebook via the Downlink Assignment Index (DAI) field of the PDCCH (or DCI). In a specific example, the DAI indicates the number of bits in the HARQ-ACK codebook and information about which channel or signal the HARQ-ACK codebook indicates whether it was successfully received or not. The terminal receives the DAI field via the PDCCH (or DCI) that schedules the PDSCH. The value of the DAI field is divided into counter-DAI and total-DAI. The total DAI indicates the number of downlink signals or channels for which the HARQ-ACK codebook indicates whether it was successfully received or not up to the current monitoring opportunity (MO). The counter-DAI indicates the bits in the HARQ-ACK codebook that indicate the success or failure of a downlink signal or channel, which is indicated via the HARQ-ACK codebook up to the current cell at the time of current monitoring. The PDCCH (or DCI) that schedules the PDSCH includes the value of the counter-DAI corresponding to the scheduled PDSCH. The PDCCH (or DCI) that schedules the PDSCH also includes the value of the total-DAI corresponding to the scheduled PDSCH. The terminal determines the number of bits in the dynamic HARQ-ACK codebook based on the information signaled by the PDCCH (or DCI). More specifically, the terminal determines the number of bits in the dynamic HARQ-ACK codebook based on the DAI of the PDCCH (or DCI).

[0117] Figure 12 is a flowchart showing an example of signaling between a terminal and a base station to which one embodiment of the present invention is applied.

[0118] Referring to Figure 12, the terminal UE receives RRC Configuration Information (S12010), which includes information for receiving Downlink Control Information (DCI) from the base station.

[0119] For example, RRC configuration information includes information about a control resource set (CORESET) and a search space for a terminal to detect a PDCCH containing downlink control information. The information about the control resource set includes at least one of the following: an identifier (ID) of the control resource set from which the terminal can detect a PDCCH containing DCI; configuration information of the control channel element (CCE); and the length (duration) or frequency resource information of the control resource set. The information about the search space includes at least one of the following: an identifier (ID) of the search space from which the terminal can detect a PDCCH containing DCI; the format of the DCI detectable from each search space; the detection interval (duration); or resource information.

[0120] Next, the terminal S12020 detects the PDCCH from the monitoring opportunity based on the RRC configuration information and receives the DCI. The terminal detects the PDCCH from the specific search space of the monitoring opportunity based on the service and / or data type based on the RRC configuration information and obtains the DCI.

[0121] In this case, the DAI included in DCI has different bits set depending on the DCI format. For example, in DCI Format 1_0, the DAI is set to 2 bits, while in DCI Format 1_1, it is set to 1 bit for a semi-static HARQ-ACK codebook and 2 bits for a dynamic HARQ-ACK codebook.

[0122] Table 3 below shows an example of DAI bits in DCI format. [Table 3]

[0123] Additionally, terminals are allocated resources via PDCCH (or DCI) for receiving PDSCH or transmitting PUSCH.

[0124] Next, the terminal receives a PDSCH or transmits a PUSCH to the base station using the allocated resources (S12030). If the terminal receives a PDSCH from the base station, it generates a HARQ-ACK codebook indicating the Ack / Nack of the received PDSCH based on the DAI value included in the PDCCH (or DCI) that schedules the PDSCH, and transmits the generated HARQ-ACK codebook to the base station in the Uplink Control Resource (UCI) (S12040).

[0125] Figure 13 shows an example of a method for a terminal to count the number of PDSCHs transmitted from a base station, based on a pseudocode applied to one embodiment of the present invention.

[0126] Figures 13(a) and (b) show an example of a method for generating and transmitting a HARQ-ACK codebook based on stored counter-DAI values, counter-DAI values ​​transmitted via a specific DCI, and stored total-DAI values.

[0127] For details, see Figure 13(a). The terminal monitors the counter-DAI value of the PDCCH (or DCI) received at the serving cell c for monitoring opportunity m.

number

number

[0128] Here, the monitoring opportunity index m and cell index c are omitted. Tables 4 and 5 show the range of values ​​for which counter-DAI or total-DAI is represented by the number of bits in counter-DAI or total-DAI. Table 4 shows an example where the number of bits in counter-DAI or total-DAI is 2 bits, and Table 5 shows an example where the number of bits in counter-DAI or total-DAI is 1 bit. [Table 4] [Table 5]

[0129] In this case, the pseudocode for generating the HARQ-ACK codebook is as shown in Table 6 below. [Table 6-1] [Table 6-2]

[0130] In this case, using the pseudocode in Table 6, the terminal is V as shown in Figure 13(a). temp and V C-DAI、c、m The values ​​are compared to determine whether the PDSCH was missed due to a failure to receive the PDCCH (or DCI) that schedules the PDSCH transmitted from the base station.

[0131] For example, as shown in Figure 13(a), when a terminal is configured with a 2-bit counter-DAI, the terminal is T D =2 2Calculate =4 and know that the range represented by the number of bits of counter-DAI is from 1 to 4. When receiving one PDCCH (or DCI), if the counter-DAI value (V C-DAI、c、m ) of that PDCCH (or DCI) is "1" and the value of V temp is "4", it is recognized that the PDSCH is transmitted continuously without omission. However, when receiving a PDCCH (or DCI), if the counter-DAI value (V C-DAI、c、m ) of that PDCCH (or DCI) is "2" and the value of V temp is "4", the terminal recognizes that the PDSCH scheduled by the PDCCH (or DCI) with a counter-DAI value of "1" is missing, and displays the HARQ-ACK for this PDSCH as NACK.

[0132] Also, as shown in FIG. 13(b), the terminal compares the values of V temp2 and V temp , which are the stored total-DAI values, to recognize the transmission omission of the PDSCH scheduled by the base station's PDCCH. For example, as shown in FIG. 13(b), when the terminal sets 2-bit total-DAI, T D = 2 2 = 4 is calculated, and the range represented by the number of bits of total-DAI is from 1 to 4. If the total-DAI value (V temp2 ) of the PDCCH (or DCI) that the terminal last received is "1" and the value of V temp is "4", it is recognized that the PDSCH is not missing after the last received PDCCH. However, if the total-DAI value (V temp2 ) of the PDCCH (or DCI) that the terminal last received is "2" and the value of V temp is "4", it is recognized that the PDSCH scheduled by one PDCCH (or DCI) is missing after the last received PDCCH, and the HARQ-ACK for this PDSCH is displayed as NACK.

[0133] In Table 6, the final HARQ-ACK codebook size for the terminal is 0 ACK It is determined by the value of [the variable].

[0134] A new DCI format will be introduced to provide ultra-reliable and low-latency communication (URLLC) services. This new DCI format has the feature of allowing the length of each DCI field to be set in order to reduce the bit size. Hereafter, these newly introduced DCI formats will be referred to as DCI format 0_2 and DCI format 1_2.

[0135] DCI format 0_2 is a DCI format for scheduling PUSCH, and DCI format 1_2 is a DCI format for scheduling PDSCH.

[0136] Furthermore, Rel-16 NR generates up to two HARQ-ACK codebooks depending on the service type. For example, one HARQ-ACK codebook is generated by collecting HARQ-ACK information from PDSCHs for eMBB services, and another HARQ-ACK codebook is generated by collecting HARQ-ACK information from PDSCHs for URLLC services. DCI formats 1_0, 1_1, and 1_2, which schedule PDSCHs, should indicate which HARQ-ACK codebook the scheduled HARQ-ACK information belongs to. Various methods can be used to specify the HARQ-ACK information in this case.

[0137] For example, by adding a separate 1-bit field to the DCI format, index 1 indicates a HARQ-ACK for PDSCHs with high priority, such as URLLC services, and index 0 indicates a HARQ-ACK for PDSCHs with low priority, such as eMBB services.

[0138] Alternatively, the HARQ-ACK of PDSCH for URLLC and the HARQ-ACK of PDSCH for eMBB are distinguished by the following parameters and / or methods:

[0139] They are distinguished by different RNTIs. In other words, the terminal distinguishes between the HARQ-ACK for URLLC and the HARQ-ACK for eMBB based on the different RNTIs of the PDCCH (or DCI) for scheduling URLLC PDSCHs and the PDCCH (or DCI) for scheduling eMBB PDSCHs, and generates a HARQ-ACK codebook.

[0140] The PDSCH is distinguished by the CORESET on which it is transmitted. In other words, the terminal distinguishes between the HARQ-ACK for the URLLC PDSCH and the HARQ-ACK for the eMBB PDSCH based on the CORESET on which the URLLC PDSCH is transmitted, and generates a HARQ-ACK codebook.

[0141] The distinction is made by the DCI format. In other words, the terminal generates HARQ-ACKs for URLLC PDSCHs and HARQ-ACKs for eMBB PDSCHs based on the DCI format for scheduling URLLC PDSCHs and the DCI format for scheduling eMBB PDSCHs. For example, DCI format 0_0 or DCI format 1_0 always schedules PUSCHs or PDSCHs with low priority. Also, DCI format 0_1 ​​or DCI format 1_1 always schedules PUSCHs or PDSCHs with low priority. Also, DCI format 0_2 or DCI format 1_2 always schedules PUSCHs or PDSCHs with high priority.

[0142] Based on this method, the terminal knows the priority of each PDSCH transmitted from the base station, collects HARQ-ACKs of PDSCHs with the same priority, and generates a HARQ-ACK codebook. Hereinafter, the HARQ-ACK codebook described in this invention refers to the HARQ-ACK codebook for HARQ-ACKs of PDSCHs with the same priority unless otherwise specified.

[0143] Figure 14 shows an example of a method for transmitting HARQ-ACKs based on downlink control information having different formats, according to one embodiment of the present invention.

[0144] The DAI received from PDCCH (or DCI) consists of counter-DAI and total-DAI, each set to a maximum of 2 bits. However, in DCI format 1_0, the number of bits for counter-DAI is fixed at 2 bits, and in DCI format 1_1, the number of bits for both counter-DAI and total-DAI is fixed at 2 bits.

[0145] The length of each DCI field in DCI format 1_2 and DCI format 0_2 is set by the base station to the terminal. For example, in DCI format 1_2, the base station sets the length of the DAI field for generating the HARQ-ACK codebook. In DCI format 1_2, the length of the DAI field is set to one of the following values: 0 bits, 1 bit, 2 bits, or 4 bits. If the length of the DAI field is set to 1 bit or 2 bits, then counter-DAI is 1 bit or 2 bits and total-DAI is 0 bits. If the length of the DAI field is set to 4 bits, then counter-DAI is 2 bits and total-DAI is 2 bits.

[0146] Referring to Figure 14, a PDSCH corresponding to one HARQ-ACK codebook for a single terminal is scheduled using DCI format 1_0, DCI format 1_1, or DCI format 1_2. In other words, the DCI formats of PDSCHs corresponding to a single HARQ-ACK codebook have different counter-DAI bit sizes. Below, we will examine how HARQ-ACK codebooks are generated when the DCI formats have different counter-DAI bit sizes.

[0147] Figure 15 shows another example of a method for transmitting HARQ-ACKs based on downlink control information having different formats, according to one embodiment of the present invention.

[0148] Referring to Figure 15, the terminal generates and transmits a HARQ-ACK codebook to the base station for each PDSCH scheduled by each PDCCH, which has a different DCI format.

[0149] More specifically, as mentioned above, if the DCI format is different, the number of bits in the DAI field included in each DCI may also be different. In this case, the terminal generates a HARQ-ACK codebook containing the HARQ-ACK bits of the PDSCH scheduled by the PDCCH (or DCI) with DAI fields having different numbers of bits, and transmits it to the base station.

[0150] In this case, the terminal has difficulty counting the received DAIs because the number of bits in the DAI fields are different. In other words, if the bit value of the DAI field of the first PDCCH (or DCI) is "0" and the bit value of the DAI field of the second DCI is "11", the terminal has difficulty determining whether the two received PDSCHs were transmitted consecutively or not.

[0151] Therefore, if the number of bits in the counter-DAI of each received PDCCH (or DCI) is different, the terminal adjusts the number of bits in the counter-DAI to be the same and recognizes which PDSCH it is. In other words, it either adjusts the number of bits by recognizing only some of the bits of the counter-DAI with more bits as valid, or by extending and interpreting the bits of the counter-DAI with fewer bits to match the number of bits.

[0152] Proposal 1: Recognize only some of the bits in the counter-DAI as valid bits and generate the HARQ-ACK codebook.

[0153] If the number of bits in the counter-DAI field of the DCI format monitored by the terminal differs, only some of the bits in the counter-DAI with more bits are recognized as valid bits to generate the HARQ-ACK codebook. In this case, the number of valid bits is the same as the number of bits in the DAI field with fewer bits among the received PDCCH (or DCI) DAI fields. Furthermore, DCI format 1_0 and DCI format 1_1 have a fixed counter-DAI of 2 bits, while DCI format 1_2 allows the counter-DAI to be set to 0 bits, 1 bit, or 2 bits. Therefore, the DAI field with fewer bits among the aforementioned DAI fields is the same as the counter-DAI included in DCI format 1_2. In other words, if the terminal is configured to monitor DCI format 1_2, it will recognize the number of bits in the counter-DAI of DCI format 1_2 as the number of valid bits, and will recognize only the number of valid bits in the 2-bit counter-DAI of DCI format 1_0 or DCI format 1_1 as valid bits for the counter-DAI.

[0154] For more details, see that the bit size of the counter-DAI in DCI format 1_2 is N.C-DAI If set to bit N, then N of the 2 bits in the counter-DAI field of other DCI formats, DCI format 1_0 and DCI format 1_1. C-DAI Only bit(s) is considered valid. In this case, the bits considered valid are LSB N. C-DAI Is it bit(s) or MSB N? C-DAI It is bit(s).

[0155] And then, N C-DAI The counter-DAI value is determined by the value of bit(s). For example, N C-DAI If the value is "1", then the number of valid bits is 1 bit. In this case, if the binary value of the valid bit is 0, the counter-DAI value is 1, and if the binary value of the valid bit is 1, the counter-DAI value is 2.

[0156] N C-DAI If the value is "2", then the number of valid bits is 2 bits. In this case, if the binary value of the valid bits is 00, the counter-DAI value is 1, and if the binary value is 01, the counter-DAI value is 2. Also, if the binary value is 10, the counter-DAI value is 3, and if the binary value is 11, the counter-DAI value is 4.

[0157] For example, as shown in Figure 15(a), N is the bit size of the counter-DAI in DCI format 1_2. C-DAI If it is set to 1 bit, the terminal will recognize only the LSB or MSB bit of the 2-bit counter-DAI in DCI format 1_0 and DCI format 1_1 as the valid number of bits in the counter-DAI.

[0158] In other words, the counter-DAI field with the smallest number of bits among the received DCIs is determined to have the number of valid bits, and only a portion of the LSB or MSB bits from the remaining DCIs' counter-DAI fields are recognized as valid, thereby matching the number of bits in the received DCI's counter-DAI.

[0159] The terminal takes the valid N from the counter-DAI field of each DCI format. C-DAI A HARQ-ACK codebook is generated using only bits. For example, Figure 15(a) shows the effective bit size N of the counter-DAI in DCI format 1_2. C-DAI This shows the binary value for counter-DAI when the value is set to 1 bit.

[0160] As shown in Figure 15(a), the counter-DAI in DCI format 1_1 has 2 bits with binary values ​​of 00, 01, 10, and 11, but only the LSB bit is valid. The invalid binary value is displayed as x. In the same monitoring opportunity, the counter-DAI value increases by 1 in ascending order of cell index.

[0161] More specifically, the counter-DAI value is determined by the number of PDCCHs transmitted to the current cell of the current monitoring opportunity. If X PDCCHs have been transmitted so far, then (X-1 mod 2^N) C-DAI The counter-DAI value is determined by ) + 1. The terminal uses the counter-DAI value to determine if there are any PDCCHs that failed to be received.

[0162] If the format of the DCI received by the terminal is DCI format 1_1, and the format of the DCI received later is also DCI format 1_1, then the valid bits of the counter-DAI are set to 1 bit. In this case, only the MSB or LSB of the counter-DAI field in DCI format 1_1 are recognized as valid bits, and invalid counter-DAI bits are not used to calculate the counter-DAI value.

[0163] For example, as shown in Figure 15(a), the number of bits N in the received DCI format 1_2 counter-DAI is C-DAI If the bit is 1 bit, the terminal determines that the number of valid bits is 1 bit, and even if the number of bits for counter-DAI in DCI format 1_1 is set to 2 bits, only the MSB or LSB bit of the 2 bits is used to determine the counter-DAI value. Therefore, the invalid bit displayed as "x" in Figure 15(a) is not used to determine the counter-DAI value.

[0164] If the counter-DAI bit in DCI format 1_2 is "0", the counter-DAI value is determined to be 1. In this case, if the two bits of the counter-DAI in the next transmitted DCI format 1_1 are "11" or "01", the terminal will use only the valid bit, the LSB value of "1", to determine the counter-DAI value. Therefore, the counter-DAI value of DCI format 1_1 will be recognized as 2.

[0165] Furthermore, Proposal 1 is interpreted as follows: The terminal determines the counter-DAI value to be 1 if the bits of the 2-bit counter-DAI in DCI format 1_0 or DCI format 1_1 are "00", to be 2 if they are "01", to be 3 if they are "10", and to be 4 if they are "11".

[0166] If the terminal is set to have 1 bit for the counter-DAI in DCI format 1_2, the terminal will determine the counter-DAI value to be either 1 or 2. Here, if the 2-bit counter-DAI value is C2, then C2 will have one of the values ​​1, 2, 3, or 4. If the 1-bit counter-DAI value is C1, then C1 will have one of the values ​​1 or 2.

[0167] In this case, the 2-bit counter-DAI value C2 is converted to the same bit value as the 1-bit counter-DAI value C1 by C1 = (C2-1) mod 2+1. This method has the same effect as determining that the LSB 1 bit is valid in Proposal 1 and interpreting the said 1-bit LSB as a 1-bit 2-bit counter-DAI value.

[0168] If the terminal receives a PDCCH (or DCI) with a counter-DAI value of 1, and then receives a PDCCH (or DCI) with a counter-DAI value of 1, the terminal recognizes that the two PDCCHs were not transmitted consecutively, and that at least one PDCCH was transmitted between the two PDCCHs but was not received by the terminal.

[0169] However, if the terminal fails to receive two consecutive PDCCH signals, it cannot recognize this. In other words, N C-DAI If this is set to 1 bit, a reception failure of up to one PDCCH can be detected, but reception failures of two or more consecutive PDCCHs cannot be detected.

[0170] As mentioned above, DCI formats 1_0 and 1_1 have a fixed counter-DAI of 2 bits. Therefore, in DCI formats 1_0 and 1_1, a counter-DAI with 2 bits could detect up to 3 consecutive PDCCH reception failures. However, Proposal 1 sets the effective number of bits to the 1 bit of the counter-DAI in DCI format 1_2, which may reduce the PDCCH reception failure detection performance.

[0171] Proposal 2: Generate the HARQ-ACK codebook based on the largest number of bits in the counter-DAI.

[0172] In the case of Proposal 1, as mentioned above, the number of valid bits in counter-DAI is only 1 bit, so it is not possible to recognize that two or more consecutive PDCCHs have not been detected. Therefore, it was not easy to detect PDCCH reception failures.

[0173] To address these issues, if the number of bits in counter-DAI differs depending on the format, the counter-DAI value is determined by extending the interpretation of the number of bits in counter-DAI based on the larger number of bits.

[0174] For more details, see that the bit size of the counter-DAI in DCI format 1_2 is N. C-DAI If set to N bits, C-DAI The bit-based counter-DAI is interpreted as a 2-bit counter-DAI value. Then, it is determined that the 2-bit counter-DAI is valid for DCI format 1_0 and DCI format 1_1.

[0175] For example, as shown in Figure 15(b), DCI format 1_0 and DCI format 1_1 both include a 2-bit counter-DAI. Therefore, if the counter-DAI bit is "00" in binary, the counter-DAI value is 1, and if it is "01" in binary, the counter-DAI value is 2. Also, if the counter-DAI bit is 10 in binary, the counter-DAI value is 3, and if it is 11 in binary, the counter-DAI value is 4.

[0176] In this case, N is the bit size of the counter-DAI in DCI format 1_2. C-DAI If the value is 1 bit, the number of bits in the counter-DAI of DCI format 1_2 is extended to 2 bits for interpretation. For example, if one bit of the counter-DAI of DCI format 1_2 is "0", extending this to 2 bits results in the counter-DAI having a bit value of "00" or "10". Therefore, the counter-DAI value is extended to 1 or 3.

[0177] Alternatively, if one bit of the counter-DAI in DCI format 1_2 is "1", extending this interpretation to two bits results in the counter-DAI having a bit value of "01" or "11". Therefore, the counter-DAI value is extended to 2 or 4.

[0178] If Proposal 2 extends the interpretation of a 1-bit size counter-DAI in DCI format 1_2 to 2 bits, the extended interpretation results in two or more candidate values ​​for the counter-DAI. In this case, the terminal recognizes the value with the smallest number of non-contiguous PDCCHs as the counter-DAI value. In other words, when interpreting the counter-DAI with an extended bit count, the terminal determines the counter-DAI value to be the one with the smallest number of undetected PDCCHs.

[0179] For example, if the previously received DCI has a 2-bit counter-DAI value of 3, and the later received PDCCH (or DCI) has a 1-bit counter-DAI value of "1", the terminal interprets the 1-bit counter-DAI as a 2-bit value and determines 4 as the counter-DAI value from among the candidate values ​​of 2 or 4, which is the value with the fewest undetected PDCCHs. In other words, if the terminal determines the counter-DAI of the later received PDCCH (or DCI) to be 2, it determines that it failed to receive two PDCCHs (or DCIs) with counter-DAI values ​​of 4 and 1. However, if the terminal determines the counter-DAI of the later received PDCCH (or DCI) to be 4, it determines that there were no PDCCHs (or DCIs) that were not received. If the probability that the terminal fails to receive a PDCCH is p, then the probability of failing to receive two consecutive PDCCHs (or DCIs) by determining counter-DAI to be 2 is p. 2 Therefore, the probability that counter-DAI is determined to be 4 and there are no PDCCH (or DCI) reception failures is 1-p. In general, for a base station to successfully receive PDCCH (or DCI) to a terminal, p is a very small value. Thus, counter-DAI 4, which has a probability of 1-p, is p 2 It occurs more frequently than counter-DAI 2, which has a probability of being 2. Therefore, in the above case, the probability of the counter-DAI value being 4 is higher than that of 2, so it is preferable to determine that the counter-DAI is 4.

[0180] Table 7 below shows an example of an extended-interpreted counter-DAI value for a previously received DCI when the counter-DAI bits are interpreted in an extended manner. Here, the counter-DAI is 1 bit, and the counter-DAI value of the previously received DCI is 2 bits. [Table 7]

[0181] In Table 7, the numbers in parentheses represent the respective bit values.

[0182] Another example from Proposal 2 is that DCI format 1_0 and DCI format 1_1 include a 2-bit counter-DAI. Therefore, if the counter-DAI bit is "00" in binary, the counter-DAI value is 1, and if it is "01" in binary, the counter-DAI value is 2. Also, if the counter-DAI bit is 10 in binary, the counter-DAI value is 3, and if it is 11 in binary, the counter-DAI value is 4.

[0183] In this case, N is the bit size of the counter-DAI in DCI format 1_2. C-DAI If the value is 0 bits, the number of bits in the counter-DAI of DCI format 1_2 is extended to 2 bits for interpretation. In this case, since the size of the counter-DAI is 0 bits, extending it to 2 bits results in a 0-bit counter-DAI having 4 candidate values.

[0184] If the terminal extends the interpretation of the counter-DAI value to the value that minimizes the number of undetected PDCCHs among the four candidate values, it determines the counter-DAI value as a value consecutive to the counter-DAI value of a previously received DCI.

[0185] Table 8 below shows an example of an extended-interpreted counter-DAI value for a previously received DCI when the counter-DAI bits are interpreted in an extended manner. Here, the counter-DAI is 0 bits, and the counter-DAI value of the previously received DCI is 2 bits. [Table 8]

[0186] That is, if the bit size of the counter-DAI of DCI format 1_2 is smaller than 2 bits, there can be multiple possible 2-bit counter-DAI values. The terminal selects one value from among the multiple possible 2-bit counter-DAI values.

[0187] To select one of the multiple candidate values, the following specific method is used.

[0188] Let the counter-DAI value of the immediately preceding received PDCCH be C, and when interpreting the currently received counter-DAI of DCI format 1_2 as 2 bits, assume the possible 2-bit counter-DAI values are i1, i2,.... The terminal should use the C value to determine one of the values of i1, i2,... as the 2-bit counter-DAI value.

[0189] [[ID=URL]] The terminal calculates the Y value based on the following Equation 2 in the order of x = 1, 2, 3,.... [Equation 2] Y = ((V temp or C) + x - 1 mod 4) + 1

[0190] If Y is one of the values of i1, i2,...., the terminal determines the 2-bit counter-DAI value as Y. This is a method for setting the 2-bit counter-DAI value so that the number of PDCCHs received unsuccessfully between the currently received DCI format 1_2 and the immediately preceding received PDCCH is minimized.

[0191] [[ID=URL]] [[ID=URL]]

[0192] [[ID=URL]] In Table 4 and Table 5, V temp is the counter-DAI value having a 2-bit size of the immediately preceding (that is, the cell with a low cell index in the current monitoring opportunity, or the PDCCH finally received in the previous monitoring opportunity) (if the previously last received DCI format is DCI format 1_2, the value interpreted as a 2-bit counter-DAI value).

[0192] For example, V tempIf the value of [[ID=]] is 1 and the counter-DAI of the currently received DCI format 1_2 is 0 in binary, it has a value of 1 or 3. If it is determined to be 3, it means that one PDCCH (counter-DAI value is 2) was transmitted between the previously received PDCCH (counter-DAI value is 1) and the currently received PDCCH (counter-DAI value is 3), but the reception failed. If it is determined to be 1, it means that three PDCCHs (counter-DAI values are 2, 3, 4) were transmitted between the previously received PDCCH (counter-DAI value is 1) and the currently received PDCCH (counter-DAI value is 1), but the reception failed. Assuming that the least number of PDCCHs were transmitted but the reception failed according to the above-described embodiments, the counter-DAI value of the currently received PDCCH is determined to be 3.

[0193] In Proposals 1 and 2, only the counter-DAI is used to generate the HARQ-ACK codebook, but the total-DAI value may be further used to generate the HARQ-ACK codebook. For example, in DCI format 1_2, the total-DAI is N T-DAI bits are set. In this case, similar to the method of Proposal 1, only the LSB (or MSB) N T-DAI of the 2-bit total-DAI field in DCI format 1_1 including the 2-bit total-DAI field is determined as the valid bit, and the total-DAI value is determined based on the valid N T-DAI bits.

[0194] As another embodiment of the present invention, a HARQ-ACK codebook is generated using a 2-bit total-DAI value. The total-DAI value is determined by the number of PDCCHs received up to the current monitoring opportunity. If the number of PDCCHs received up to the current monitoring opportunity is T, the N T-DAI bit total-DAI is determined to be ((T - 1) mod 2^N T-DAI ) + 1. The PDCCHs received in one monitoring opportunity have the same 2-bit total-DAI value.

[0195] In yet another embodiment of the present invention, if at least one DCI format 1_1 is received in a single monitoring opportunity, the 2-bit total-DAI value contained in DCI format 1_1 is used. That is, if a DCI format containing a 2-bit total-DAI and a DCI format containing a 1-bit total-DAI or a 0-bit total-DAI are received in the same monitoring opportunity, the 2-bit total-DAI value is assumed because it can contain the most information.

[0196] In yet another embodiment of the present invention, if DCI format 1_1 is not received during a single monitoring opportunity, but DCI format 1_2 is received, the 2-bit total-DAI value is determined as follows.

[0197] N is the bit size of the total-DAI in DCI format 1_2. T-DAI If the value is 1 bit, it is extended and interpreted as a 2-bit total-DAI value. For example, if the bit of the 1-bit total-DAI is "0", the total-DAI value is 1 or 3, and if it is "1", the total-DAI value is 2 or 4.

[0198] N is the bit size of the total-DAI in DCI format 1_2. T-DAI If the value is 0 bits (i.e., total-DAI is not included in the DCI format), then the 0-bit total-DAI is interpreted as a 2-bit total-DAI value.

[0199] For example, a 0-bit total-DAI value can be 1, 2, 3, or 4. In other words, if the total-DAI bit size in DCI format 1_2 is less than 2 bits, a 2-bit total-DAI has multiple candidate values. In this case, one value is selected from among the multiple candidate values ​​in the following manner.

[0200] Currently, the 2-bit counter-DAI value of the PDCCH received at the end of the monitoring opportunity (i.e., received from the cell with the highest cell index) is C, and the possible 2-bit total-DAI values ​​of the total-DAI included in the DCI of the PDCCH received during that monitoring opportunity are j1, j2, ...

[0201] In this case, the terminal should use the C value to determine one of j1, j2, ... as the 2-bit total-DAI value. The terminal then calculates the Z value sequentially based on the x (x=0, 1, 2, 3, ...) values ​​using formula 3 below. [Formula 3] Z=((V temp2 Alternatively, C)+x-1 mod 4)+1

[0202] If Z is one of the values ​​j1, j2, ..., the terminal determines the 2-bit total-DAI value to be Z. This is a way to set the 2-bit total-DAI value so that the number of PDCCHs that were not received after the last PDCCH of the current monitoring opportunity is minimized.

[0203] Table 9 below shows an example of a total-DAI value selected from several candidate values. [Table 9]

[0204] In Table 9, V temp2 This is the 2-bit counter-DAI value of the last PDCCH among the PDCCHs received at the end of the monitoring opportunity. For example, the previous V temp2 If the value of is 2 and the received DCI format 1_2 total-DAI is binary 0, then the total-DAI has a value of 1 or 3.

[0205] If the total-DAI value is determined to be 3, it means that one PDCCH (counter-DAI value 3) was transmitted after the last received PDCCH (counter-DAI value 2), but the terminal failed to detect it. If the total-DAI value is determined to be 1, it means that three PDCCHs (counter-DAI values ​​3, 4, and 1) were transmitted after the last received PDCCH (counter-DAI value 2), but the terminal failed to detect them. Assuming that the fewest number of PDCCHs were transmitted according to the above embodiment but reception failed, the total-DAI value of the received PDCCH is determined to be 3.

[0206] In this manner, even if the number of bits in the counter-DAI or total-DAI of DCIs with different formats differs, the terminal determines the valid number of bits or interprets the bits in an extended way, multiplexes the HARQ-ACK codebook for PDSCHs scheduled by multiple DCIs, and transmits it to the base station.

[0207] Figure 16 shows an example of a method for transmitting HARQ-ACK based on downlink control information for uplink and downlink scheduling according to one embodiment of the present invention.

[0208] Referring to Figure 16, the terminal multiplexes the HARQ-ACK codebook, which includes the HARQ-ACK bits of the PDSCH scheduled via the DCI of the PDCCH, and the PUSCH scheduled via the DCI, and transmits them to the base station.

[0209] Specifically, as shown in FIG. 16, the terminal multiplexes (or piggybacks) the received HARQ-ACK bits of the PDSCH onto the PUSCH and transmits them to the base station. At this time, the DCI format for scheduling the PDSCH is DCI format 1_0, DCI format 1_1, and / or DCI format 1_2. And the DCI formats for scheduling the PUSCH onto which the HARQ-ACK bits are multiplexed (or piggybacked) include DCI format 0_0, DCI format 0_1, and / or DCI format 0_2, etc.

[0210] The length of the UL DAI field included in DCI format 0_2 is set to 0, 1, or 2 bits. And the length of the counter DAI field included in DCI format 1_2 is set to 0, 1, or 2 bits.

[0211] Also, DCI format 0_0 and DCI format 0_1 include a 2-bit UL DAI field, and DCI format 1_0 and DCI format 1_1 include a 2-bit counter-DAI field.

[0212] At this time, if the length of the UL DAI field is not the same as the length of the counter-DAI field in DCI format 1_2, it is necessary to determine the UL DAI field value based on the counter-DAI field. Hereinafter, in the embodiments, it is assumed that the length of the DAI field is at least not 0. That is, the DCI format includes at least a DAI field with a length of 1 bit or more.

[0213] As a first embodiment, if the length of the UL DAI field is greater than the length of the counter-DAI field in DCI format 1_2 (for example, if the length of the UL DAI field is 2 bits and the length of the counter-DAI field is 1 bit), the terminal determines that only some bits in the UL DAI field are valid bits of the UL DAI field. Here, the number of bits of some bits is the same as the number of bits of the counter-DAI field, and they are the bits closest to the MSB or LSB of the UL DAI field.

[0214] The terminal calculates the UL DAI value using the bits determined to be valid bits among the bits of the UL DAI field. If the valid bit of the UL DAI field is 1 bit, if the 1 bit is "0", the UL DAI value is 1, and if it is 1, the UL DAI value is 2.

[0215] If the valid bits of the UL DAI field are 2 bits, if the 2 bits are 00, the UL DAI value is 1, if they are 01, the UL DAI value is 2. Also, if the 2 bits are 10, the UL DAI value is 3, and if they are 11, the UL DAI value is 4.

[0216] The terminal determines the number of HARQ-ACK bits for the PDSCHs that could not be received using the UL DAI value obtained using the bits of the UL DAI field determined to be valid and the counter-DAI value obtained from the counter-DAI field.

[0217] For example, let the UL DAI value be X and the counter-DAI value be Y. If X = Y, it is determined that there is no PDSCH that could not be received. However, if Y < X, it is determined that X - Y PDSCHs could not be received, and if X < Y, it is determined that T - (Y - X) PDSCHs could not be received. Here, T = 2 N where N is the number of bits of the counter-DAI field.

[0218] In a second embodiment, if the length of the UL DAI field is greater than the length of the counter-DAI field in DCI format 1_2 (for example, if the length of the UL DAI field is 2 bits and the length of the counter-DAI field is 1 bit), the terminal first determines the UL DAI value based on the length of the UL DAI field, and then modifies the determined UL DAI value with the counter-DAI field to determine the final UL DAI value.

[0219] The process for first determining the UL DAI value based on the length of the UL DAI field is as follows: If the length of the UL DAI field is 1 bit, then if the bit value is "0", the UL DAI value is 1, and if the bit value is "1", the UL DAI value is 2.

[0220] If the length of the UL DAI field is 2 bits, then if the bit value is "00", the UL DAI value is 1, and if the bit value is "01", the UL DAI value is 2. Also, if the bit value is "10", the UL DAI value is 3, and if the bit value is "11", the UL DAI value is 4.

[0221] Once the UL DAI value is determined by the UL DAI field, the terminal modifies the determined UL DAI value to match the counter-DAI field, and determines the final UL DAI value as follows:

[0222] N is the number of bits in the counter-DAI field, T=2 N If the determined UL DAI value is Z, the final UL DAI value (X) is calculated using the following formula 4. [Equation 4] Final UL DAI value (X) = ((Z-1) mod T) + 1

[0223] The terminal determines the number of HARQ-ACK bits for PDSCHs that could not be received by using the final UL DAI value (X) and the counter-DAI value obtained from the counter-DAI field. For example, if the counter-DAI value is Y, when X = Y, it is determined that there is no PDSCH that could not be received. However, when Y < X, it is determined that X - Y PDSCHs could not be received, and when X < Y, it is determined that T - (Y - X) PDSCHs could not be received. Here, T = 2 N where N is the number of bits of the counter-DAI field.

[0224] As a third embodiment, if the length of the UL DAI field is greater than the length of the counter-DAI field of DCI format 1_2 (for example, if the length of the UL DAI field is 2 bits and the length of the counter-DAI field is 1 bit), the terminal assumes (or recognizes) that the range of the UL DAI field value is the same as the range of values that the counter-DAI can indicate. For example, if the values that the counter-DAI can indicate are 1, 2, 3, 4, the UL DAI value is recognized as one of the values 1, 2, 3, 4.

[0225] Specifically, the terminal determines the UL DAI value according to the length of the UL DAI field. If the length of the UL DAI field is 1 bit and the bit value is "0", the UL DAI value is 1, and if it is 1, the UL DAI value is 2. If the UL DAI field is 2 bits, when the bit value is "00", the UL DAI value is 1, and if it is 01, the UL DAI value is 2. Also, if the 2-bit value is "10", the UL DAI value is 3, and if it is "11", the UL DAI value is 4.

[0226] The UL DAI value should always be within the range of values ​​that the counter-DAI can indicate. For example, if the length of the UL DAI field is 2 bits, the range of UL DAI values ​​is 1, 2, 3, and 4. If the range of values ​​that the counter-DAI can have is 1 and 2, then the length of the UL DAI field is 2 bits, but the possible UL DAI values ​​are 1 and 2.

[0227] In other words, the terminal does not expect to be instructed to display an UL DAI value that deviates from the range of values ​​that counter-DAI can hold. It does not expect to be instructed to display 10 or 11, which indicates an UL DAI value of 3 or 4. Therefore, if it is instructed to display this value, the terminal will determine it to be an error case.

[0228] As mentioned above, the length of the UL DAI field in DCI format 0_2 is set to 0, 1, or 2 bits. If the length of such a UL DAI field is less than 2 bits, the UL DAI is determined in the same way as the 2-bit total-DAI value.

[0229] In other words, the UL DAI value is determined using the last received 2-bit counter-DAI value. Table 10 below shows an example of a 2-bit UL DAI value. [Table 10]

[0230] In Table 10, V temp3 This is the 2-bit counter-DAI value of the last PDCCH among the received PDCCHs. For example, the previous V temp3 If the value of is 2 and the bit value of the UL DAI in DCI format 0_2 received is "0", then the UL DAI has a value of 1 or 3.

[0231] If the UL DAI value is determined to be 3, it means that one PDCCH (counter-DAI value 3) was transmitted after the last received PDCCH (counter-DAI value 2) but reception failed. If the UL DAI value is determined to be 1, it means that three PDCCHs (counter-DAI values ​​3, 4, and 1) were transmitted after the last received PDCCH (counter-DAI value 2) but reception failed. As described above, if it is assumed that the fewest number of PDCCHs were transmitted but reception failed, the 2-bit UL DAI value is determined to be 3.

[0232] Figure 17 shows an example of a downlink assignment indicator for each downlink control information detected from a monitoring opportunity according to one embodiment of the present invention.

[0233] In another embodiment of the present invention, if the bit size of the UL DAI field in DCI format 0_0, 0_1, or 0_2 is different from the bit size of the counter-DAI field in DCI format 1_0, 1_1, or DCI format 1_2, the terminal will perform the following actions:

[0234] The bit size of the counter-DAI field in DCI format 1_0, 1_1, or 1_2 is N. C-DAI If it's bits, the counter-DAI value is 1, 2, ..., 2^N C-DAI This is shown by the following: Here, the largest value C D is 2^N C-DAI If this is the case, that is, the size of the bits in the counter-DAI field is N. C-DAI If it is 2 bits, the bit value of the counter-DAI field is 1 if it is "00", 2 if it is "01", 3 if it is "10", and 4 if it is "11". In this case C D The value is 4.

[0235] Or, N C-DAI If it is 1 bit, the bit value of the counter-DAI field is 1 if it is "0", and 2 if it is "1", CD The value is 2.

[0236] If the terminal receives a DCI format for scheduling a PDSCH at the serving cell c, and the counter-DAI value of the received DCI format is V C-DAI、c、m If so, the terminal will schedule the PDSCH to the current serving cell c of the current monitoring opportunity m when the DCI format is received. D *j+V C-DAI、c、m It is determined that j has received a certain number of items. Here, j is a non-negative integer.

[0237] In other words, if X is the number of DCI formats that schedule PDSCH up to the current serving cell c of the current monitoring opportunity m in which the DCI format was received, then the counter-DAI value of that DCI format is V. C-DAI、c、m =(X-1 mod C D ) + 1.

[0238] The bit size of the UL DAI field in DCI format 0_0, 0_1, or 0_2 is N UL-DAI For bits, the UL DAI value is 1, 2, ..., 2^N UL-DAI This is shown by the following: Here, the largest value U D is 2^N UL-DAI If this is the case, that is, the bit size N of the UL DAI field. UL-DAI If it is 2 bits, then the bit value of the UL DAI field is 1 if it is "00", 2 if it is "01", 3 if it is "10", and 4 if it is "11". And U D The value is 4.

[0239] If the terminal receives a DCI format to schedule a PUSCH on monitoring opportunity m, and the UL-DAI value of the received DCI format is V UL-DAI、m If so, the terminal will schedule the PDSCH until the current monitoring opportunity m in which the DCI format is received.D *i+V UL-DAI、m Determine that 'i' has been received. Here, i is a non-negative integer.

[0240] In other words, if X is the number of DCI formats for which PDSCH will be scheduled up to the current monitoring opportunity m in which a DCI format has been received, then the UL-DAI value of that DCI format is V. UL-DAI、m =(X-1 mod U D ) + 1.

[0241] For example, U D The value of C is 4. D If the value is 2, the counter-DAI value will be 1 or 2, and the UL-DAI value will be 1, 2, 3, or 4. Figure 17(a) shows an example of a DCI format counter-DAI value received in monitoring opportunities (MO) #0 to #6.

[0242] According to the definition of the counter-DAI value, the counter-DAI value of the DCI format received from MO#0 is 1, the counter-DAI value of the DCI format received from MO#1 is 2, the counter-DAI value of the DCI format received from MO#2 is 1, the counter-DAI value of the DCI format received from MO#3 is 2, the counter-DAI value of the DCI format received from MO#4 is 1, the counter-DAI value of the DCI format received from MO#5 is 2, and the counter-DAI value of the DCI format received from MO#6 is 1. Then, the terminal receives a DCI format to schedule a PUSCH. The UL DAI value of the received DCI format is 3. This is because seven DCI formats to schedule PDSCHs were received earlier.

[0243] This invention proposes a method for a terminal to generate a HARQ-ACK codebook when the bit size of the counter DAI and the bit size of the UL DAI are different. In Figure 17(b), assume that the terminal failed to receive the DCI format for MO#4 and MO#5. The terminal received a DCI format with a counter-DAI value of 2 for MO#3 and a DCI format with a counter-DAI value of 1 for MO#6, so the terminal is unaware of the failure to receive the DCI formats for MO#4 and MO#5. Therefore, the terminal generates only the HARQ-ACK bits for the DCI formats received for MO#0, MO#1, MO#2, MO#3, and MO#6 and includes them in the HARQ-ACK codebook.

[0244] If the terminal receives a UL-DAI value of 3 in a DCI format that schedules a PUSCH, the terminal recognizes that there are two more DCI formats in addition to the five DCI formats it has successfully received. Therefore, the terminal generates HARQ-ACK bits for a total of seven DCI formats and includes them in the HARQ-ACK codebook.

[0245] Figure 19 shows an example of a method for transmitting HARQ-ACKs based on downlink control information having different formats, based on pseudocode according to one embodiment of the present invention.

[0246] Referring to Figure 19, a HARQ-ACK codebook is generated using pseudocode, the UL-DAI value, and the counter-DAI value, and then transmitted to the base station. Figure 19 shows an example of multiplexing a 2-bit UL-DAI and a 1-bit counter-DAI.

[0247] In detail, as one embodiment of the present invention, the UL-DAI value and counter-DAI value are used as follows. First, as shown in Figure 19(a), the counter-DAI value received by the terminal from the last MO is V tempLet it be so. As described above, this counter - DAI value has one value among 1, 2, …, C D Let the UL DAI value received by the terminal in the DCI format for scheduling PUSCH be V temp2 The terminal generates a HARQ - ACK codebook through the following process.

[0248] First, the terminal determines the number W temp of DCI formats that scheduled PDSCH with V temp . W temp is determined by the following Equation 5. [Equation 5] W temp = C D * j + V temp

[0249] In Equation 5, the initial j value is set to 0, and if the counter - DAI value of the DCI format that currently schedules PDSCH in the MO is smaller than the counter - DAI value of the DCI format that scheduled PDSCH in the previous MO, it is incremented by 1. That is, the DCI formats with counter - DAI values of 1, 2, …, C D are grouped into one group, and j indicates how many such groups have been received. In FIG. 17(b), j = 2.

[0250] Next, the terminal converts the number (W temp ) of DCI formats that scheduled PDSCH into V’ UL-DAI , which is the counter - DAI value corresponding to the bit size N temp of the UL DAI field as shown in FIG. 19(b). Here, V’ temp is determined by the following Equation 6. [Equation 6] V’ temp = ((W temp - 1) mod U D ) + 1

[0251] In Equation 6, V’temp Like UL DAI, 1, 2, ..., U D It has one of the values. The terminal is V'. temp and V temp2 The j-value is determined by comparing V. temp2 <V’ temp If so, the j-value is determined by the following formula 7.

number

[0252] Otherwise, j remains unchanged. Using the j value, the terminal uses the size O of the HARQ-ACK codebook. ACK Determine if the terminal is configured to receive only 1TB per PDSCH. ACK This is calculated by formula 8 below.

number

[0253] If the terminal is configured to receive 2TB per PDSCH, then ACK This is calculated by formula 9 below.

number

[0254] This can be represented in pseudocode as shown in Table 11 below. [Table 11-1] [Table 11-2] [Table 11-3]

[0255] Figure 18 shows another example of a downlink assignment indicator for each downlink control information detected from a monitoring opportunity according to one embodiment of the present invention.

[0256] In another embodiment of the present invention, if the bit size of the total DAI field in DCI format 1_0, 1_1, or 1_2 differs from the bit size of the counter-DAI field in DCI format 1_0, 1_1, or DCI format 1_2, the terminal generates a HARQ-ACK codebook by the following operation:

[0257] The bit size of the counter-DAI field in DCI format 1_0, 1_1, or 1_2 is N. C-DAI If it's bits, the counter-DAI value is 1, 2, ..., 2^N C-DAI This is shown by the following: Here, the largest value C D is 2^N C-DAI If this is the case, that is, the size of the bits in the counter-DAI field is N. C-DAI If it is 2 bits, the bit value of the counter-DAI field is 1 if it is "00", 2 if it is "01", 3 if it is "10", and 4 if it is "11". In this case C D The value is 4.

[0258] Or, N C-DAI If it is 1 bit, then the bit value of the counter-DAI field is 1 if it is 0, and 2 if it is 1. D The value is 2.

[0259] If the terminal receives a DCI format and schedules PDSCH 6 on the serving cell c, and the counter-DAI value of the received DCI format is V C-DAI、c、m If so, the terminal will schedule the PDSCH to the current serving cell c of the current monitoring opportunity m when the DCI format is received. D *j+V C-DAI、c、m It is determined that j has received a certain number of items. Here, j is a non-negative integer.

[0260] In other words, if X is the number of DCI formats that schedule PDSCH up to the currently serving cell c of the current monitoring opportunity m in which the DCI format was received, then the counter-DAI value V of that DCI format is C-DAI、c、m =(X-1 mod C D ) + 1.

[0261] The bit size of the total DAI field in DCI format 1_0, 1_1, or 1_2 is N. T-DAI If we consider bits, the total-DAI value can be 1, 2, ..., 2^N. T-DAI This is shown by the following: Here, the largest value T D is 2^N T-DAI If this is the case, that is, the bit size N of the total DAI field. T-DAI If it is 2 bits, the bit value of the total DAI field is 1 if it is 00, 2 if it is 01, 3 if it is 10, and 4 if it is 11. And T D The value is 4.

[0262] If the terminal receives a DCI format to schedule a PUSCH on monitoring opportunity m, and the total DAI value of the received DCI format is V T-DAI、m If so, the terminal will schedule the PDSCH until the current monitoring opportunity m in the DCI format T D *i+V T-DAI、m It is determined that 'i' has been received. Here, i is a non-negative integer.

[0263] In other words, if X is the number of DCI formats for which PDSCH will be scheduled up to the current monitoring opportunity m in which a DCI format was received, then the total DAI value of that DCI format is V. T-DAI、c、m =(X-1 mod T D ) + 1.

[0264] T D The value of C is 4. DLet's examine the case where the value is 2 as an example. The terminal's counter-DAI value is set to 1 or 2, and the total-DAI has a value of 1, 2, 3, or 4.

[0265] Figure 18(a) shows the (counter-DAI, total-DAI values) in DCI format received by MO#0~#6. According to the definitions of counter-DAI and total DAI values, the (counter-DAI, total-DAI) of the DCI format received from MO#0 is (1,1), the (counter-DAI, total-DAI) of the DCI format received from M1#0 is (2,2), the (counter-DAI, total-DAI) of the DCI format received from MO#2 is (1,3), the (counter-DAI, total-DAI) of the DCI format received from MO#3 is (2,4), the (counter-DAI, total-DAI) of the DCI format received from MO#4 is (1,1), the (counter-DAI, total-DAI) of the DCI format received from MO#5 is (2,2), and the (counter-DAI, total-DAI) of the DCI format received from MO#6 is (1,3).

[0266] As another example of the present invention, we propose a method for a terminal to generate a HARQ-ACK codebook when the bit size of the counter DAI and the bit size of the total DAI are different. As shown in Figure 18(b), the terminal may not be able to receive the DCI format for MO#4 and MO#5. In this case, the terminal has received a DCI format with a counter-DAI value of 2 for MO#3 and a DCI format with a counter-DAI value of 1 for MO#6, and therefore cannot recognize the failure to receive the DCI format for MO#4 and MO#5.

[0267] Therefore, the terminal generates only the HARQ-ACK bits for the DCI format received via MO#0, MO#1, MO#2, MO#3, and MO#6, and includes them in the HARQ-ACK codebook.

[0268] If the terminal receives a total-DAI value of 3 in a DCI format for scheduling PDSCH, the terminal determines that there are two more DCI formats in addition to the five DCI formats it successfully received. Therefore, the terminal generates HARQ-ACK bits for a total of seven DCI formats and includes them in the HARQ-ACK codebook.

[0269] As one embodiment of the present invention, the total-DAI value and counter-DAI value are used as follows. First, the counter-DAI value received by the terminal from the last MO is V temp As mentioned above, the counter-DAI values ​​are 1, 2, ..., C D It has one of the values. The total DAI value received in DCI format by the terminal to schedule PDSCH is V temp2 In that case, the terminal generates the HARQ-ACK codebook through the following process:

[0270] First, the terminal is V temp W is the number of DCI formats scheduled for PDSCH. temp This is determined by the following formula 10. [Formula 10] W temp =C D *j+V temp

[0271] In equation 10, the initial value of j is set to 0, and if the counter-DAI value of the DCI format used to schedule PDSCH on the current MO is smaller than the counter-DAI value of the DCI format used to schedule PDSCH on the previous MO, it is increased by 1.

[0272] In other words, the counter-DAI values ​​are 1, 2, ..., C D The DCI format is grouped into one group, and j indicates how many of these grouped groups were received. In Figure 18(a), j=2.

[0273] Next, the terminal scheduled the PDSCH for a number of DCI format W temp N is the bit size of the total-DAI field. T-DAI V' is the corresponding counter-DAI value. temp Convert to this. This is done by formula 11 below. [Equation 11] V' temp =((W temp -1)mod T D )+1

[0274] In equation 11, V' temp Like total-DAI, 1, 2, ..., T D It has one of the values. The terminal is V'. temp and V temp2 The j-value is determined by comparing V. temp2 <V’ temp If so, the j-value is calculated using the following formula 12.

number

[0275] Otherwise, j remains unchanged. Using the j value, the terminal uses the size O of the HARQ-ACK codebook. ACK Determine if the terminal is configured to receive only 1TB per PDSCH. ACK This is calculated by the following formula 13.

number

[0276] If the terminal is configured to receive 2TB per PDSCH, thenACK This is calculated by the following formula 14.

number

[0277] In yet another embodiment of the present invention, if the bit sizes of the counter-DAI fields in DCI format 1_0, 1_1, or 1_2 are different, the terminal behaves as follows:

[0278] When monitoring opportunity m, the bit size of the counter-DAI field in DCI format 1_0, 1_1, or 1_2 received by serving cell c is N. C-DAI、c、m The number of bits is 1, 2, ..., 2^N. In this case, the counter-DAI value is 1, 2, ..., 2^N. C-DAI、c、m This is shown by the following: Here, the largest value C D、c、m is 2^N C-DAI、c、m Therefore, the bit size N of the counter-DAI field. C-DAI、c、m If it is 2 bits, the bit value of the counter-DAI field is 1 if it is "00", 2 if it is "01", 3 if it is "10", and 4 if it is "11". And C D The value of N is 4. C-DAI、c、m If it is 1 bit, then the bit value of the counter-DAI field is 1 if it is 0, and 2 if it is 1. And C D、c、m The value is 2.

[0279] If the terminal receives a DCI format for scheduling a PDSCH at the serving cell c, and the counter-DAI value of the received DCI format is V C-DAI、c、m If so, the terminal will schedule the PDSCH to the current serving cell c of the current monitoring opportunity m in the DCI format C D、c、m *j+V C-DAI、c、m It is determined that j has received a certain number of items. Here, j is a non-negative integer.

[0280] In other words, if X is the number of DCI formats that schedule PDSCH up to the currently serving cell c of the current monitoring opportunity m in which the DCI format was received, then the counter-DAI value V of that DCI format is C-DAI、c、m (X-1 mod C D、c、m ) + 1.

[0281] This invention proposes a method for a terminal to generate a HARQ-ACK codebook when the bit sizes of the counter-DAIs differ. In one embodiment of this invention, the counter-DAI values ​​are used as follows.

[0282] N C-DAI、c、m This is the smallest bit size among the bit sizes of the counter DAI field in DCI format, and C D、min The value of is 2^(N) C-DAI、min ) For example, if the bit size of the counter DAI field in one DCI format is 2 bits and the bit size of the counter DAI field in another DCI format is 1 bit, then N C-DAI、min The value is 1, C D、min The value is 2.

[0283] During monitoring opportunity m, the counter-DAI value received in serving cell c is V. C-DAI、c、m Therefore, as mentioned above, the counter-DAI values ​​are 1, 2, ..., C D、c、m It has one of the following values. First, the terminal is V C-DAI、c、m The number of DCI formats S scheduled for PDSCH c、m This is determined based on the following formula 15.

number

[0284] In formula 15, floor(j*C D、min / C D、c、m )*C D、c、mThe part is the number of DCI formats that scheduled the PDSCH (S c、m ) is (S c、m -1 mod C D、c、m ) + 1 = V C-DAI、c、m This is the part that satisfies the requirement.

[0285] In other words, in equation 15, the j value is adjusted by scaling and / or flooring so that the value of is a multiple of .

[0286] The terminal currently has monitoring opportunity m, and has obtained a number S in DCI format based on the counter-DAI value received by serving cell c. c、m And the number of DCI formats calculated just before this, W temp Compare. If S c、m ≤W temp If this is satisfied, S c、m >W temp The j-value increases until it reaches a certain point. During this process, the j-value increases by 1 each time. c、m >W temp In that case, j will remain as it is.

[0287] j is C D、min This parameter indicates how many DCI format data entries were received.

[0288] This can be represented in pseudocode as shown in Table 12 below. [Table 12-1] [Table 12-2] [Table 12-3]

[0289] In Table 12, when the HARQ-ACK codebook is multiplexed with PUSCH, T D =U D Then, after the while loop, V temp2This is set to the UL DAI value.

[0290] DCI format 1_2 may not include counter-DAI (which may be set to 0 bits). In this case, the terminal may have an ambiguous way of determining the dynamic HARQ-ACK codebook. That is, when designing the dynamic HARQ-ACK codebook (type-2 HARQ-ACK codebook), the base station may configure it to omit some fields in the DCI field to increase the probability of the terminal successfully receiving the PDCCH. In other words, the base station may omit some of the DCI fields or set the size of the fields to 0 bits.

[0291] For example, a base station may omit the counter-DAI field from the DCI field transmitted to the terminal, or set the field size to 0 bits.

[0292] As mentioned above, in a dynamic HARQ-ACK codebook, the counter-DAI field is used not only to determine the position of a single HARQ-ACK bit within the HARQ-ACK codebook, but also to determine the size of the HARQ-ACK codebook.

[0293] In order for a terminal to transmit HARQ-ACK bits to the base station to notify it of ACK / NACK (or DTX) for multiple PDSCHs into the HARQ-ACK codebook, the DCI counter-DAI field values ​​should be sorted in ascending order. However, if the counter-DAI field is omitted, it is not possible to sort the counter-DAI field values ​​in ascending order via explicit values. Therefore, a method is needed to determine the order of HARQ-ACK bits within the HARQ-ACK codebook.

[0294] Therefore, we will investigate methods for generating a HARQ-ACK codebook based on certain criteria, even when some fields of the DCI are omitted.

[0295] Figure 20 shows an example of a method for transmitting HARQ-ACK to PDSCH according to the reception order of PDCCH according to one embodiment of the present invention.

[0296] Referring to Figure 20, if the DAI field is partially omitted or its size is set to 0 bits, the terminal generates a HARQ-ACK codebook based on the order in which the PDCCHs were received for scheduling the PDSCH, rather than the counter-DAI value.

[0297] In a first embodiment of the present invention, the terminal determines the order of HARQ-ACK bits for a PDSCH in the HARQ-ACK codebook based on the time information of the PDCCH that schedules the PDSCH. In other words, the terminal determines the order of HARQ-ACK bits included in the HARQ-ACK codebook based on the order in which the PDCCH was received, regardless of the counter-DAI value, for the PDCCH transmitted to schedule the PDSCH.

[0298] For example, as shown in Figure 20(a), if the start symbol of the CORESET or search space containing the PDCCH scheduling the first PDSCH is located ahead of the start symbol of the CORESET or search space containing the PDCCH scheduling the second PDSCH, then, as shown in Figure 20(b), the HARQ-ACK bit B(1) of the first PDSCH in the HARQ-ACK codebook will be located ahead of the HARQ-ACK bit B(0) of the second PDSCH. If the start symbols of the CORESET or search space are the same, the last symbol of the CORESET or search space will be located one HARQ-ACK bit ahead of the PDSCH scheduled by the earlier PDCCH.

[0299] Figure 21 shows an example of a method for transmitting a HARQ-ACK to a PDSCH using the time information of a PDSCH according to one embodiment of the present invention.

[0300] Referring to Figure 21, if the DAI field is partially omitted or its size is set to 0 bits, the terminal generates the HARQ-ACK codebook using the PDSCH time information contained in the PDCCH for scheduling the PDSCH, rather than the counter-DAI value.

[0301] In a second embodiment of the present invention, the terminal determines the order of the HARQ-ACK bits of the PDSCH that constitute the HARQ-ACK codebook based on the time information of the PDSCH. Specifically, if the start symbol of the first PDSCH is located at a symbol earlier than the start symbol of the second PDSCH, then in the HARQ-ACK codebook, the position of the HARQ-ACK bit for the first PDSCH is earlier than the HARQ-ACK bit for the second PDSCH.

[0302] For example, as shown in Figure 21(a), based on the time information contained in the PDCCH for scheduling the first PDSCH and the time information contained in the PDCCH for scheduling the second PDSCH, the start symbol of the second PDSCH is positioned before the start symbol of the first PDSCH. In this case, as shown in Figure 21(b), when the terminal transmits the HARQ-ACK for the first PDSCH and the HARQ-ACK for the second PDSCH by PUCCH, the HARQ-ACK bit B(1) for the second PDSCH is positioned ahead of the HARQ-ACK bit B(0) for the first PDSCH.

[0303] Figure 22 shows an example of transmitting a HARQ-ACK to a PDSCH using the HARQ process ID (or HARQ process number) of the PDCCH that schedules the PDSCH according to one embodiment of the present invention.

[0304] Referring to Figure 22, if the DAI field is partially omitted or its size is set to 0 bits, the terminal generates the HARQ-ACK codebook using the HARQ process ID (or HARQ process number) contained in the PDCCH for scheduling the PDSCH, rather than the counter-DAI value.

[0305] In a third embodiment of the present invention, the terminal determines the order of the HARQ-ACK bits in the HARQ-ACK codebook based on the HARQ process ID (or HARQ process number) value of the PDCCH that schedules the PDSCH.

[0306] In more detail, if we assume that the HARQ process ID of the first PDSCH is A in the PDCCH that schedules the first PDSCH, and the HARQ process ID of the second PDSCH is B in the PDCCH that schedules the second PDSCH, then in the HARQ-ACK codebook, the HARQ-ACK bit of the PDSCH with the smaller value of A and B will be placed ahead of the HARQ-ACK bit of the PDSCH with the larger value.

[0307] In other words, the position of the HARQ-ACK bit is determined by the ascending order of the HARQ-ACK process IDs. Here, the terminal assumes that the HARQ process IDs of HARQ-ACKs transmitted to a single HARQ-ACK codebook are all different values. Therefore, it is not expected that a single HARQ-ACK codebook will be generated that has the same HARQ process ID for all PDSCHs having the same HARQ-ACK bit.

[0308] For example, if the number of bits in the counter-DAI field contained in at least one of the PDCCHs scheduling the first PDSCH and the PDCCH scheduling the second PDSCH are different, or if the field is omitted or set to 0 bits, the terminal generates a HARQ-ACK codebook based on the HARQ-ACK process ID contained in the PDCCH scheduling each PDSCH and transmits it to the base station via UCI.

[0309] In this case, as shown in Figure 22(a), the HARQ-ACK process ID or HARQ-ACK process number of the PDCCH for scheduling the second PDSCH is "0", and the HARQ-ACK process ID or HARQ-ACK process number of the PDCCH for scheduling the first PDSCH is "1". In this case, as shown in Figure 15(b), based on the ascending order of the HARQ-ACK process IDs or HARQ-ACK process numbers, the HARQ-ACK bit B(0) for the second PDSCH with the lower HARQ-ACK process ID or HARQ-ACK process number is located ahead of the HARQ-ACK bit B(1) for the first PDSCH.

[0310] In a fourth embodiment of the present invention, the terminal uses cell information that received the PDCCH scheduling each PDSCH to determine the order of the HARQ-ACK bits of the PDSCH in the HARQ-ACK codebook. The cell information represents the cell index (or ID). The terminal is configured to monitor PDCCHs in multiple cells. In this case, the terminal receives different PDCCHs in different cells. In the HARQ-ACK codebook, the terminal arranges the order of the HARQ-ACK bits of the PDSCHs received in different cells in ascending order of the index of the cell that received the PDCCH scheduling the PDSCH.

[0311] In a fifth embodiment of the present invention, the terminal uses the information of the CORESET (or search space) that received the PDCCH scheduling the PDSCH to determine the order of the HARQ-ACK bits of the PDSCH and generates a HARQ-ACK codebook. Here, the information of the CORESET (or search space) becomes the index (or ID) of the CORESET (or search space).

[0312] The terminal is configured to monitor PDCCHs in multiple CORESETs (or search spaces). In this case, the terminal receives different PDCCHs in different CORESETs (or search spaces). The terminal then generates a HARQ-ACK codebook by arranging the HARQ-ACK bits of the PDSCHs received in different CORESETs (or search spaces) in ascending order of the index of the CORESET (or search space) that received the PDCCH that scheduled the PDSCH.

[0313] As a sixth embodiment of the present invention, the terminal uses frequency domain information to determine the order of the HARQ-ACK bits of the PDSCH in the HARQ-ACK codebook, which is used to schedule the PDSCH. Here, the frequency domain information is the lowest PRB index among the PRBs to which the PDCCH is assigned. Here, the index means the common PRB index, and this index indicates how far it is from Point A in the frequency domain. Point A is the reference frequency used by the terminal during the initial access process, and in detail, Point A is as follows.

[0314] - fsetToPointA indicates the frequency offset between Point A and the lowest subcarrier of the lowest resource block. The lowest resource block has the subcarrier spacing provided by the higher-level parameter SubCarrierSpacingCommon and overlaps with the SS / PBCH block used by the terminal for initial cell selection. offsetToPointA is expressed in resource block units, assuming a 15kHz subcarrier spacing for FR1 and a 60kHz subcarrier spacing for FR2.

[0315] The absoluteFrequencyPointA, which indicates the frequency position of Point A, is represented by the Absolute Radio Frequency Channel Number (ARFCN) in all other cases.

[0316] The terminal is configured to monitor multiple PDCCHs and receive different PDCCHs in different frequency domains. In this case, the terminal arranges the order of the HARQ-ACK bits of the PDCCHs received in different frequency domains in the HARQ-ACK codebook in ascending order of the lowest PRB index of the PDCCH that schedules the PDCCH. This method determines the order of the HARQ-ACK bits in the HARQ-ACK codebook when multiple PDCCHs are received by the terminal in a single CORESET (or search space) in the fifth embodiment.

[0317] The first to sixth embodiments described above are used in combination with each other, thereby allowing the terminal to determine the order of HARQ-ACK bits for each PDSCH in the HARQ-ACK codebook. For example, the first and third embodiments are combined. In this combination, the order of HARQ-ACK bits in the HARQ-ACK codebook is first determined by the time-domain information of the PDCCH. If the order cannot be determined by the time-domain information, the order is determined by the HARQ process ID according to the third embodiment. Alternatively, the first, fourth, fifth, and sixth embodiments are combined. In this combination, the order of HARQ-ACK bits in the HARQ-ACK codebook is first determined by the time-domain information of the PDCCH. Next, if the order cannot be determined by the time-domain information according to each embodiment, the order is determined by the cell information. If the order cannot be determined by the cell information, the order is determined by the CORESET (or search space) information. Furthermore, if the order cannot be determined by the CORESET (or search space) information, the order is determined by the frequency-domain allocation information of the PDCCH.

[0318] Furthermore, in another embodiment of the present invention, if a terminal has multiple PDCCHs, each PDSCH is scheduled via multiple PDCCHs, and the number of bits in the counter-DAI field contained in the multiple PDCCHs are different, the HARQ-ACK codebook is not multiplexed based on the number of bits, but is generated individually for each counter-DAI.

[0319] For example, if the counter-DAI field has 2 bits or 1 bit, the terminal generates and transmits to the base station a HARQ-ACK codebook for PDSCHs scheduled by a PDCCH containing a counter-DAI with 2 bits, and / or for PDSCHs scheduled by a PDCCH containing a counter-DAI with 1 bit.

[0320] In other words, a terminal's HARQ-ACK codebook contains only HARQ-ACKs from PDSCHs, etc., scheduled in DCI format, etc., that have the same counter-DAI bit count.

[0321] In the first to sixth embodiments described above, the terminal determines the position of the HARQ-ACK bit in the HARQ-ACK codebook without the counter-DAI field. However, when the terminal generates the HARQ-ACK codebook containing the HARQ-ACK bits for each PDSCH, problems may arise when determining the size of the HARQ-ACK codebook.

[0322] For example, if a terminal fails to receive one of the PDCCHs, it may misjudge the size of the HARQ-ACK codebook due to the unreceived PDCCH, so a method is needed to resolve this.

[0323] In this case, the terminal always assumes that when the size of the dynamic HARQ-ACK codebook is divided by X, the remainder is Y. Preferably, X=4 and Y=1. That is, the size of the dynamic HARQ-ACK codebook is determined to be one of 1, 5, 9, ... bits. When the terminal receives a PDCCH scheduling Z PDSCHs, the terminal determines the size of the HARQ-ACK codebook to be the smallest value greater than or equal to Z. For example, if Z=3, the terminal determines the size of the HARQ-ACK codebook to be 5.

[0324] A single HARQ-ACK codebook may or may not include a counter-DAI field in the DCI of a PDCCH corresponding to a HARQ-ACK. In this case, within the HARQ-ACK codebook, the terminal should determine the location of the HARQ-ACK of a PDSC scheduled with a DCI that includes the counter-DAI field, and the location of the HARQ-ACK of a PDSCH scheduled with a DCI that does not include the counter-DAI field.

[0325] In one embodiment of the present invention, the terminal generates separate HARQ-ACK codebooks depending on whether the DCI includes a counter-DAI field or not.

[0326] In detail, the terminal collects only the HARQ-ACKs of PDSCHs scheduled by DCI containing the counter-DAI field and generates a first sub-HARQ-ACK codebook. In this case, the position of the HARQ-ACK within the first sub-HARQ-ACK codebook is determined using the value of the counter-DAI field (i.e., the position is determined by the ascending order of the counter-DAI). If the number of bits in the counter-DAI fields are different, the methods of the first to sixth embodiments and combinations thereof described above are used.

[0327] The terminal then generates a second sub-HARQ-ACK codebook by collecting only the HARQ-ACKs of PDSCHs scheduled by DCI, where the counter-DAI field is either omitted or set to 0 bits. In this case, the position of the HARQ-ACK within the second sub-HARQ-ACK codebook is determined by the first to sixth embodiments and their combinations. The terminal generates a HARQ-ACK codebook by sequentially combining the first sub-HARQ-ACK codebook and the second sub-HARQ-ACK codebook (i.e., the first bit of the second sub-HARQ-ACK codebook follows the last bit of the first sub-HARQ-ACK codebook). This method may increase the complexity of the terminal because the terminal must create two sub-HARQ-ACK codebooks using different methods.

[0328] In another embodiment of the present invention, in the situation described above, the terminal ignores the counter-DAI field included in the DCI. That is, all DCIs are treated as DCIs without a counter-DAI field, and the position of the HARQ-ACK bit in the HARQ-ACK codebook is determined in the first to sixth embodiments and combinations thereof.

[0329] In yet another embodiment of the present invention, a terminal configured with a semi-static HARQ-ACK codebook determines the HARQ-ACK bit for a single PDSCH.

[0330] In detail, a terminal configured with a semi-static HARQ-ACK codebook should transmit a HARQ-ACK codebook containing a predetermined number of HARQ-ACK bits to the PUCCH. This predetermined number is determined independently of which PDSCH the terminal is actually scheduled to use, and is derived from the higher-level configuration.

[0331] The higher-level information includes at least the cell's CBG setting information, and the terminal sets the CBG setting information for each cell. The CBG setting information is used to set the maximum number of CBGs that a single PDSCH (or TB) can contain, N MAX This is represented as follows. In the semi-static HARQ-ACK codebook, when including HARQ-ACK bits from PDSCHs, it should be determined how many bits of HARQ-ACK a single PDSCH corresponds to. Generally, if CBG transmission is not configured, a PDSCH corresponds to 1 bit of HARQ-ACK (2 bits if 2TB transmission is configured), and if CBG transmission is configured, the PDSCH corresponds to N MAX Supports HARQ-ACK bits.

[0332] If a semi-static HARQ-ACK is configured on the terminal, the predetermined number of HARQ-ACK bits should be included in the PUCCH as described above. Even if CBG-based transmission is configured, under certain circumstances, the terminal will transmit only a 1-bit HARQ-ACK to the PDSCH in the PUCCH.

[0333] For example, if CBG-based transmission is configured, and at least one of the following conditions is satisfied, and one downlink cell (or carrier) is configured on the terminal, and there is one monitoring opportunity to receive a PDCCH, the terminal will generate only 1 bit of the SPS PDSCH, or SPS PDSCH release DCI, or PDSCH HARQ-ACK.

[0334] If a terminal is to transmit a HARQ-ACK for a single SPS PDSCH,

[0335] When one SPS PDSCH release DCI is received,

[0336] When transmitting HARQ-ACKs for PDSCH scheduled in DCI format 1_0 or DCI format 1_2.

[0337] In other words, even if CBG-based transmission is configured, the terminal will only generate 1 bit of HARQ-ACK per PDSCH.

[0338] Conversely, if CBG-based transmission is configured, and at least one of the following conditions is met, and the terminal has two or more downlink cells (or carriers) configured, or there are two or more monitoring opportunities to receive PDCCH, then the terminal will send N 1-bit SPS PDSCH, or SPS PDSCH release DCI, or PDSCH HARQ-ACK (TB-level HARQ-ACK). MAX Repeat this N times MAX Generate bits.

[0339] If you need to transmit a HARQ-ACK to a single SPS PDSCH,

[0340] When one SPS PDSCH release DCI is received,

[0341] When transmitting HARQ-ACKs for PDSCH scheduled in DCI format 1_0 or DCI format 1_2.

[0342] In other words, in accordance with the CBG-based transmission, the terminal has N per PDSCH. MAX Generates only the bitwise HARQ ACK.

[0343] In the operation described above, DCI format 1_2 is a DCI format that sets the size of each field for high reliability and low latency. This DCI format 1_2 does not support the operation of the CBG infrastructure. In other words, PDSCH scheduled in DCI format 1_2 always corresponds to 1 bit of TB-level HARQ-ACK. This is similar to DCI format 1_0. Therefore, it is treated the same as DCI format 1_0.

[0344] Figure 23 is a sequence diagram showing an example of the operation of a terminal for transmitting HARQ-ACK based on downlink information having different formats, according to one embodiment of the present invention.

[0345] Referring to Figure 23, the terminal generates a HARQ-ACK codebook containing HARQ-ACK bits for multiple PDSCHs scheduled by the DCIs of multiple PDCCHs transmitted from the base station. In this case, if the DCI formats are different from each other and the number of bits in the DAI field contained in each DCI is different, the terminal will generate the HARQ-ACK codebook by interpreting the value of the DAI field under certain conditions.

[0346] First, the terminal receives the first PDCCH (Phase 1 Digital Shared Channel) for scheduling the first downlink physical shared channel (PDSCH) (S23010). Before receiving the first PDCCH, the terminal receives configuration information containing the information needed to receive the PDCCH.

[0347] The first PDCCH includes a first counter downlink assignment indicator (DAI) indicating the number of PDSCHs scheduled up to the serving cell at the time the first PDCCH is monitored, and a first total DAI indicating the total number of PDSCHs scheduled in the serving cell up to the time the PDCCH is monitored.

[0348] Next, the terminal receives a second PDCCH for scheduling the second PDSCH, which includes the second counter DAI and the second overall DAI (S23020).

[0349] Next, the terminal receives the first PDSCH based on the first PDCCH 23030, and the terminal receives the second PDSCH based on the second PDCCH S23040.

[0350] After receiving the first PDSCH and the second PDSCH, the terminal generates HARQ-ACK bits for the first and second PDSCH, respectively, and uses the generated HARQ-ACK bits to generate a HARQ-ACK codebook.

[0351] Next, the terminal transmits uplink control information (UCI), including the HARQ-ACK codebook, to the base station (S23050).

[0352] If the number of bits in the first counter DAI and the second counter DAI are different, the value of the second counter DAI is recognized based on the number of bits in the first counter DAI. In other words, if the number of bits in the first counter DAI and the second counter DAI are different, the terminal generates a HARQ-ACK codebook including HARQ-ACK bits using the methods of Proposals 1 to 3 described above.

[0353] For example, if the number of bits in the first counter DAI is less than the number of bits in the second counter DAI, the value indicated by the second counter DAI is determined based on at least one bit of the second counter DAI, in the same number as the number of bits in the first counter DAI.

[0354] Alternatively, if the number of bits in the first counter DAI is greater than the number of bits in the second counter DAI, the value indicated by the second counter DAI is interpreted by extending the number of bits in the second counter DAI to the same number of bits as the first counter DAI.

[0355] In this case, if there are multiple candidate values ​​for the second counter DAI, the second counter DAI value is interpreted as the value with the smallest difference from the value indicated by the first counter DAI among the multiple candidate values.

[0356] Figure 24 is a sequence diagram showing an example of base station operation for receiving HARQ-ACKs based on downlink information having different formats, according to one embodiment of the present invention.

[0357] Referring to Figure 24, the base station schedules a PDSCH to a terminal via multiple PDCCHs having different formats. In this case, if the number of bits in the DCI field contained in the different formats of the PDCCHs differs, the base station receives HARQ-ACK codebooks from the terminal for the PDSCHs scheduled by the different formats of DCI.

[0358] First, the base station transmits the first PDCCH to the terminal for scheduling the first downlink physical shared channel (PDSCH) (S24010). Before transmitting the first PDCCH, the base station transmits configuration information that includes information for receiving the PDCCH.

[0359] The first PDCCH includes a first counter downlink assignment indicator (DAI) indicating the number of PDSCHs scheduled up to the serving cell at the time the first PDCCH is monitored, and a first total DAI indicating the total number of PDSCHs scheduled in the serving cell up to the time the PDCCH is monitored.

[0360] Next, the base station transmits a second PDCCH for scheduling the second PDSCH, which includes the second counter DAI and the second overall DAI, in S24020.

[0361] Next, the base station transmits the first PDSCH based on the first PDCCH, and transmits the second PDSCH based on the second PDCCH.

[0362] The base station receives a HARQ-ACK codebook from the terminal via uplink control information (UCI), which includes HARQ-ACK bits for the first and second PDSCHs, respectively, generated by the terminal (S24050).

[0363] If the number of bits in the first counter DAI and the second counter DAI are different, the value of the second counter DAI is recognized based on the number of bits in the first counter DAI. In other words, if the number of bits in the first counter DAI and the second counter DAI are different, the terminal generates a HARQ-ACK codebook including HARQ-ACK bits using the methods of Proposals 1 to 3 described above.

[0364] For example, if the number of bits in the first counter DAI is less than the number of bits in the second counter DAI, the value indicated by the second counter DAI is determined based on at least one bit of the second counter DAI, with the same number of bits as the number of bits in the first counter DAI.

[0365] Alternatively, if the number of bits in the first counter DAI is greater than the number of bits in the second counter DAI, the value indicated by the second counter DAI is interpreted by extending the number of bits in the second counter DAI to the same number of bits as the first counter DAI.

[0366] In this case, if there are multiple candidate values ​​for the second counter DAI, the second counter DAI value is interpreted as the value with the smallest difference from the value indicated by the first counter DAI among the multiple candidate values.

[0367] The above description of the present invention is illustrative, and a person with ordinary skill in the art to which the invention pertains will understand that it can be easily modified into other specific forms without altering the technical idea or essential features of the invention. Therefore, the above embodiments should be understood to be illustrative and not limiting in all respects. For example, each component described as a single form may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0368] The scope of the present invention is indicated by the claims described below rather than by the detailed description above, and all modifications or altered forms derived from the meaning and scope of the claims and the concept of equivalents thereto should be interpreted as being included within the scope of the present invention. [Explanation of symbols]

[0369] 100 devices 110 processors 120 Communication Modules 130 memory 140 User Interfaces 150 display units 200 base stations 210 processors 220 Communication Module 230 memory

Claims

1. A terminal of a wireless communication system, Communication module and A processor that controls the communication module, The aforementioned processor, Receiving the first downlink physical control channel (PDCCH) for scheduling the first downlink physical shared channel (PDSCH), The first PDCCH includes a first counter downlink assignment indicator (DAI) indicating the number of PDSCHs scheduled up to the serving cell at the time the first PDCCH is monitored, and a first total DAI indicating the total number of PDSCHs scheduled in the serving cell up to the time the PDCCH is monitored, and to receive, Receiving the second PDCCH for scheduling the second PDSCH, The second PDCCH includes a second counter DAI and a second overall DAI, and is capable of receiving, Receiving the first PDSCH based on the first PDCCH, Receiving the second PDSCH based on the second PDCCH, Transmitting Uplink Control Information (UCI) including a HARQ (Hybid Automatic Repeat Request)-ACK (acknowledge) codebook for the first PDSCH and the second PDSCH to the base station, It is configured to do the following: If the number of bits in the first counter DAI and the number of bits in the second counter DAI are different, the value of the second counter DAI is determined based on the number of bits in the first counter DAI. Terminal.

2. The terminal according to claim 1, wherein if the number of bits of the first counter DAI is less than the number of bits of the second counter DAI, the value indicated by the second counter DAI is determined based on at least one bit of the second counter DAI in the same number as the number of bits of the first counter DAI.

3. The terminal according to claim 2, where if there are multiple values ​​determined by at least one bit of the second counter DAI, the same number of bits as the first counter DAI, the value of the second counter DAI is determined to be the value among the multiple values ​​that has the smallest difference from the value indicated by the first counter DAI.

4. The terminal according to claim 3, wherein if the first counter DAI is 1 bit and the second counter DAI is 2 bits, the value of the second counter DAI is determined using the LSB (Least Significant Bit) or MSB (Most Significant Bit) of the 2 bits.

5. The terminal according to claim 4, wherein if one bit of the first counter DAI is "0", the value of the second counter DAI is determined to be "2" if the LSB or MSB of the second counter DAI is "0", and the value of the second counter DAI is determined to be "1" if the LSB or MSB of the second counter DAI is "1".

6. The terminal according to claim 4, wherein if one bit of the first counter DAI is "1", the value of the second counter DAI is "1" if the LSB or MSB of the second counter DAI is "1", and the value of the second counter DAI is determined to be "2" if the LSB or MSB of the second counter DAI is "0".

7. The terminal according to claim 1, wherein if the number of bits of the first counter DAI is greater than the number of bits of the second counter DAI, the value indicated by the second counter DAI is determined by extending the number of bits of the second counter DAI to the same number of bits as the number of bits of the first counter DAI.

8. The terminal according to claim 7, where if there are multiple values ​​of the second counter DAI determined by extending the number of bits to the same number of bits as the first counter DAI, the value of the second counter DAI is determined to be the value among the multiple values ​​that has the smallest difference from the value indicated by the first counter DAI.

9. The terminal according to claim 7, where if the first counter DAI is 2 bits and the second counter DAI is 1 bit, the value of the second counter DAI is determined by expanding the 1 bit to 2 bits.

10. If two bits of the first counter DAI are "00" or "01", and one bit of the second counter DAI is "0", then the second counter DAI is determined to be "3". The terminal according to claim 9, wherein if two bits of the first counter DAI are "10" or "11" and one bit of the second counter DAI is "1", the second counter DAI is determined to be "1".

11. If two bits of the first counter DAI are "01" or "10", and one bit of the second counter DAI is "1", then the second counter DAI is determined to be "4". The terminal according to claim 9, wherein if two bits of the first counter DAI are "00" or "11" and one bit of the second counter DAI is "1", the second counter DAI is determined to be "2".

12. In a wireless communication system, in a method of receiving data performed by a terminal, the method performed by the terminal is: The step of receiving a first downlink physical control channel (PDCCH) for scheduling a first downlink physical shared channel (PDSCH), The first PDCCH includes a first counter downlink assignment indicator (DAI) indicating the number of PDSCHs scheduled up to the serving cell at the time the first PDCCH is monitored, and a first total DAI indicating the total number of PDSCHs scheduled in the serving cell up to the time the PDCCH is monitored, A step of receiving a second PDCCH for scheduling a second PDSCH, The second PDCCH includes a second counter DAI and a second overall DAI, and the steps are: The steps include receiving the first PDSCH based on the first PDCCH, The steps include receiving the second PDSCH based on the second PDCCH, The procedure includes the step of transmitting uplink control information (UCI) to the base station, which includes a HARQ (Hybid Automatic Repeat Request)-ACK (acknowledge) codebook for the first PDSCH and the second PDSCH, A method for determining the value of the second counter DAI based on the number of bits of the first counter DAI when the number of bits of the first counter DAI is different.

13. The method according to claim 12, wherein if the number of bits of the first counter DAI is less than the number of bits of the second counter DAI, the value indicated by the second counter DAI is determined based on at least one bit of the second counter DAI that is equal to the number of bits of the first counter DAI.

14. The method according to claim 13, wherein if there are multiple values ​​determined by at least one bit of the second counter DAI, the same number of bits as the first counter DAI, the second counter DAI value is determined to be the value among the multiple values ​​that has the smallest difference from the value indicated by the first counter DAI.

15. The method according to claim 14, wherein if the first counter DAI is 1 bit and the second counter DAI is 2 bits, the value of the second counter DAI is determined using the LSB (Least Significant Bit) or MSB (Most Significant Bit) of the 2 bits.

16. The method according to claim 15, wherein if one bit of the first counter DAI is "0", and the LSB or MSB of the second counter DAI is "0", the value of the second counter DAI is determined to be "2", and if the LSB or MSB of the second counter DAI is "1", the value of the second counter DAI is determined to be "1".

17. The method according to claim 15, wherein if one bit of the first counter DAI is "1", the value of the second counter DAI is "1" if the LSB or MSB of the second counter DAI is "1", and the value of the second counter DAI is determined to be "2" if the LSB or MSB of the second counter DAI is "0".

18. The method according to claim 12, wherein if the number of bits of the first counter DAI is greater than the number of bits of the second counter DAI, the value indicated by the second counter DAI is determined by extending the number of bits of the second counter DAI to the same number of bits as the number of bits of the first counter DAI.

19. The method according to claim 18, where if there are multiple values ​​of the second counter DAI determined by extending the number of bits to the same number of bits as the first counter DAI, the value of the second counter DAI is determined to be the value among the multiple values ​​that has the smallest difference from the value indicated by the first counter DAI.

20. The method according to claim 18, wherein if the first counter DAI is 2 bits and the second counter DAI is 1 bit, the value of the second counter DAI is determined by expanding the 1 bit to 2 bits.

21. If two bits of the first counter DAI are "00" or "01", and one bit of the second counter DAI is "0", then the second counter DAI is determined to be "3". The method according to claim 20, wherein if two bits of the first counter DAI are "10" or "11" and one bit of the second counter DAI is "1", the second counter DAI is determined to be "1".

22. If two bits of the first counter DAI are "01" or "10", and one bit of the second counter DAI is "1", then the second counter DAI is determined to be "4". The method according to claim 20, wherein if two bits of the first counter DAI are "00" or "11" and one bit of the second counter DAI is "1", the second counter DAI is determined to be "2".

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