CN118020266A

CN118020266A - Method for transmitting uplink channel in wireless communication system and apparatus therefor

Info

Publication number: CN118020266A
Application number: CN202280065455.4A
Authority: CN
Inventors: 石根永; 卢珉锡; 孙周亨; 郭真三
Original assignee: Wilus Institute of Standards and Technology Inc
Current assignee: Wilus Institute of Standards and Technology Inc
Priority date: 2021-09-27
Filing date: 2022-09-27
Publication date: 2024-05-10

Abstract

The invention relates to a method and a device thereof for use in a wireless communication system, comprising the steps of: transmitting an uplink channel on a set of time slots; and transmitting the DMRS for transmission of the uplink channel on the set of time slots, wherein the DMRS is transmitted for maintaining phase continuity and power consistency over a plurality of consecutive time slots in the time window, and when the length of the time window is not configured by the base station, determining the time window according to the scheme of the present invention.

Description

Method for transmitting uplink channel in wireless communication system and apparatus therefor

Technical Field

The present specification relates to a wireless communication system, and more particularly, to a method for transmitting an uplink channel and an apparatus thereof.

Background

After commercialization of the fourth generation (4G) communication system, efforts are being made to develop a new fifth generation (5G) communication system in order to meet the increasing demand for wireless data services. The 5G communication system is called a super 4G network communication system, a LTE-after system, or a New Radio (NR) system. In order to achieve a high data transmission rate, 5G communication systems include systems that operate using a millimeter wave (mmWave) band of 6GHz or higher, and include communication systems that operate using a band of 6GHz or lower in terms of ensuring coverage, so that implementation in base stations and terminals is under consideration.

The third generation partnership project (3 GPP) NR system improves the spectral efficiency of the network and enables communication providers to provide more data and voice services over a given bandwidth. Thus, 3GPP NR systems are designed to meet the demand for high-speed data and media transmission in addition to supporting a large amount of voice. The advantages of NR systems are higher throughput and lower latency on the same platform, support for Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD), and low operating costs due to enhanced end user environments and simple architecture. For more efficient data processing, dynamic TDD of NR systems may use a method for changing the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols that can be used in uplink and downlink according to the data traffic direction of cell users. For example, when there is more downlink traffic than uplink traffic for a cell, the base station may allocate multiple downlink OFDM symbols to a slot (or subframe). Information about the slot configuration should be transmitted to the terminal.

In order to mitigate path loss of radio waves and increase transmission distance of radio waves in mmWave frequency band, in 5G communication systems, beamforming, massive multiple input/output (massive MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, hybrid beamforming combining analog beamforming and digital beamforming, and massive antenna techniques are discussed. Further, for network improvement of the system, in the 5G communication system, technology development is being performed regarding an evolved small cell, an advanced small cell, a cloud radio access network (cloud RAN), an ultra dense network, device-to-device communication (D2D), vehicle-to-everything communication (V2X), a wireless backhaul, a non-terrestrial network communication (NTN), a mobile network, cooperative communication, coordinated multipoint (CoMP), interference cancellation, and the like. Furthermore, in the 5G system, hybrid FSK with QAM modulation (FQAM) and Sliding Window Superposition Coding (SWSC) as Advanced Coding Modulation (ACM) schemes, and Filter Bank Multicarrier (FBMC), non-orthogonal multiple access (NOMA) and Sparse Code Multiple Access (SCMA) as advanced connection techniques are being developed.

Meanwhile, in human-centric connection networks where humans generate and consume information, the internet has evolved into an internet of things (IoT) network that exchanges information between distributed components such as objects. Internet of everything (IoE) technology combining IoT technology with big data processing technology through a connection with a cloud server is also emerging. In order to implement IoT, technical elements such as sensing technology, wired/wireless communication and network infrastructure, service interface technology, and security technology are required, so that technologies such as sensor networks, machine-to-machine (M2M), and machine-type communication (MTC) have been studied in recent years to connect between objects. In an IoT environment, intelligent Internet Technology (IT) services can be provided that collect and analyze data generated from networked objects to create new value in human life. Through the fusion and mixing of existing Information Technology (IT) and various industries, ioT can be applied in fields such as smart homes, smart buildings, smart cities, smart cars or networked cars, smart grids, healthcare, smart appliances and advanced medical services.

Accordingly, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, machine-to-machine (M2M), and Machine Type Communications (MTC) are implemented through technologies such as beamforming, MIMO, and array antennas. The application of the cloud RAN as the big data processing technology described above is an example of a fusion of 5G technology and IoT technology. In general, a mobile communication system is developed to provide a voice service while ensuring activities of users.

However, the mobile communication system is gradually expanding not only a voice service but also a data service, and has now been developed to the extent of providing a high-speed data service. However, in the mobile communication system currently providing services, a more advanced mobile communication system is required due to a resource shortage phenomenon and high-speed service demands of users.

Disclosure of Invention

Technical problem

The present disclosure is directed to providing a method for efficiently performing a wireless signal transmission or reception process and an apparatus therefor.

The technical problems to be solved by the present invention are not limited to the above technical problems, and other technical features not mentioned can be clearly understood by those skilled in the art to which the present disclosure pertains from the following description.

Technical proposal

As an aspect of the present disclosure, there is provided a User Equipment (UE) for use in a wireless communication system, the UE including a communication module; and a processor configured to control the communication module, wherein the processor is configured to: performing transmission of an uplink channel on a set of time slots, and transmitting a demodulation reference signal (DMRS) for the transmission of the uplink channel on the set of time slots, wherein when configuring the joint channel estimation operation, the DMRS is transmitted such that phase continuity and power consistency over a plurality of consecutive time slots within a time window are maintained, and when the length of the time window is not configured by the base station, the time window is determined based on a smaller one of the following values: (1) The number of time slots comprising the transmission of the uplink channel; and (2) a maximum number of time slots in which the UE can maintain phase continuity and power consistency according to the UE capability.

As another aspect of the present disclosure, there is provided a method for use by a User Equipment (UE) in a wireless communication system, the method comprising: performing transmission of an uplink channel on a set of time slots, and transmitting a demodulation reference signal (DMRS) for transmission of the uplink channel on the set of time slots, wherein when configuring joint channel estimation operation, the DMRS is transmitted such that phase continuity and power consistency over a plurality of consecutive time slots within a time window are maintained, and when the length of the time window is not configured by the base station, then the time window is determined based on a smaller value between: (1) a number of time slots comprising uplink channel transmissions; and (2) a maximum number of time slots in which the UE can maintain phase continuity and power consistency according to UE capabilities.

Preferably, when joint channel estimation operation is not configured, DMRS may be used for slot-based individual channel estimation.

Preferably, when the length of the time window is configured by the base station, it may be determined that the time window is configured by the base station.

Preferably, the number of time slots including the transmission of the uplink channel may correspond to the number of time slots from the time slot in which the transmission of the uplink channel starts to the time slot in which the transmission of the uplink channel ends.

Preferably, the number of time slots comprising transmissions of the uplink channel may correspond to the number of consecutive time slots comprising transmissions of the uplink channel.

Preferably, the uplink channel may include PUCCH repeated transmission or PUSCH repeated transmission.

Preferably, the uplink channel may include PUSCH retransmission type A, PUSCH retransmission type B, PUSCH transmission of a Transport Block Size (TBS) determined with reference to a plurality of slots, or PUSCH retransmission of a TBS determined with reference to a plurality of slots.

Advantageous effects of the invention

According to the present disclosure, a wireless signal transmission or reception process can be efficiently performed.

The technical problems to be solved by the present disclosure are not limited to the above technical problems, and other technical features not mentioned can be clearly understood by those skilled in the art to which the present disclosure pertains from the following description.

Drawings

Fig. 1 illustrates an example of a radio frame structure used in a wireless communication system.

Fig. 2 illustrates an example of a Downlink (DL)/Uplink (UL) slot structure in a wireless communication system.

Fig. 3 is a diagram for explaining physical channels used in a 3GPP system and a typical signal transmission method using the same.

Fig. 4a and 4b illustrate SS/PBCH blocks for initial cell access in a 3GPP NR system.

Fig. 5a and 5b illustrate a procedure for transmitting control information and a control channel in a 3GPP NR system.

Fig. 6 illustrates a control resource set (CORESET) in which a Physical Downlink Control Channel (PDCCH) may be transmitted in a 3GPP NR system.

Fig. 7 illustrates a method for configuring a PDCCH search space in a 3GPP NR system.

Fig. 8 is a conceptual diagram illustrating carrier aggregation.

Fig. 9 is a diagram for explaining single carrier communication and multi-carrier communication.

Fig. 10 is a diagram showing an example in which a cross-carrier scheduling technique is applied.

Fig. 11 is a block diagram illustrating a configuration of a UE and a base station according to an embodiment of the present disclosure.

Fig. 12 illustrates a method of scheduling a Physical Uplink Shared Channel (PUSCH) in the time domain.

Fig. 13 illustrates a method of scheduling PUSCH in the frequency domain.

Fig. 14 illustrates repeated transmission of PUSCH.

Fig. 15 illustrates a method of scheduling PUSCH.

Fig. 16 illustrates repeated transmission of PUSCH.

Fig. 17 illustrates a problem that occurs when PUSCH repetition transmission is performed in the TDD case.

Fig. 18 illustrates a problem that occurs when PUCCH repeated transmission is performed in a TDD case.

Fig. 19 illustrates PUCCH resource configuration.

Fig. 20 illustrates PUCCH repetition occupying the same symbol.

Fig. 21 illustrates scheduling of one physical uplink shared channel.

Fig. 22 illustrates scheduling of multiple physical uplink shared channels.

Fig. 23 illustrates PUCCH repetition transmission.

Fig. 24 illustrates PUCCH repetition transmission and intra-slot frequency hopping.

Fig. 25 illustrates PUCCH repetition transmission and inter-slot frequency hopping.

Fig. 26 illustrates a slot index determination method for PUCCH frequency hopping according to an example of the present disclosure.

Fig. 27 illustrates a slot index determination method for PUCCH frequency hopping according to an example of the present disclosure.

Fig. 28 illustrates a slot index determination method for PUCCH frequency hopping according to an example of the present disclosure.

Fig. 29 illustrates a slot index determination method for PUCCH frequency hopping according to an example of the present disclosure.

Fig. 30 illustrates a slot index determination method for PUCCH frequency hopping according to an example of the present disclosure.

Fig. 31 illustrates a slot index determination method for PUCCH frequency hopping according to an example of the present disclosure.

Fig. 32 illustrates a method for repeatedly mapping PUCCH to frequency hopping according to an example of the present disclosure.

Fig. 33 illustrates a method for repeatedly mapping PUCCH to frequency hopping according to an example of the present disclosure.

Fig. 34 illustrates a method for repeatedly mapping PUCCH to frequency hopping according to an example of the present disclosure.

Fig. 35 illustrates a method for repeatedly mapping PUCCH to frequency hopping according to an example of the present disclosure.

Fig. 36 illustrates a method for repeatedly mapping PUCCH to frequency hopping according to an example of the present disclosure.

Fig. 37 illustrates a method for repeatedly mapping PUCCH to frequency hopping according to an example of the present disclosure.

Fig. 38 illustrates a TDW determination method according to an example of the present disclosure.

Fig. 39 illustrates a TDW indication method of the UE.

Fig. 40 illustrates a TDW indication method according to an example of the present disclosure.

Fig. 41 illustrates a TDW indication method according to an example of the present disclosure.

Fig. 42 illustrates a TDW indication method according to an example of the present disclosure.

Fig. 43 illustrates a problem that occurs when the TDW is determined in the CA case.

Fig. 44 illustrates a problem that occurs when the TDW is determined in the CA case.

Fig. 45 illustrates a TDW indication method according to an example of the present disclosure.

Fig. 46 illustrates a TDW indication method according to an example of the present disclosure.

Fig. 47 illustrates a TDW indication method according to an example of the present disclosure.

Fig. 48 illustrates a TDW indication method according to an example of the present disclosure.

Fig. 49 illustrates a TDW indication method according to an example of the present disclosure.

Fig. 50 illustrates a TDW indication method according to an example of the present disclosure.

Fig. 51 illustrates a method for determining a time slot for applying a TDW according to an example of the present disclosure.

Fig. 52 illustrates a method for determining a time slot for applying TDW according to an example of the present disclosure.

Fig. 53 illustrates a problem that occurs when the UE determines the TDW.

Fig. 54 illustrates a method for determining a TDW according to an example of the present disclosure.

Fig. 55 illustrates a method for determining a TDW according to an example of the present disclosure.

Fig. 56 illustrates a method for determining TDW according to an example of the present disclosure.

Fig. 57 illustrates a problem that occurs when the UE determines the TDW.

Fig. 58 and 59 illustrate an uplink channel transmission method according to an example of the present disclosure.

Detailed Description

The terms used in the specification adopt general terms currently widely used as much as possible by considering functions in the present invention, but may be changed according to the intention, habit, and appearance of new technology of those skilled in the art. In addition, in a specific case, there are terms arbitrarily selected by the applicant, and in this case, the meaning thereof will be described in the corresponding description section of the present invention. Therefore, it is intended that the terms used in the specification be construed not only based on the names of the terms but also based on the essential meanings of the terms and contents throughout the specification.

Throughout the specification and claims which follow, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element or "electrically connected" to the other element through a third element. In addition, unless explicitly described to the contrary, the word "comprising" will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. Furthermore, in some exemplary embodiments, limitations such as "greater than or equal to" or "less than or equal to" based on a particular threshold, respectively, may be appropriately replaced with "greater than" or "less than," respectively.

The following techniques may be used in various wireless access systems: such as Code Division Multiple Access (CDMA), frequency Division Multiple Access (FDMA), time Division Multiple Access (TDMA), orthogonal Frequency Division Multiple Access (OFDMA), single carrier-FDMA (SC-FDMA), and the like. CDMA may be implemented by wireless technology such as Universal Terrestrial Radio Access (UTRA) or CDMA 2000. TDMA may be implemented by wireless technologies such as global system for mobile communications (GSM)/General Packet Radio Service (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented by wireless technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA (E-UTRA), and the like. UTRA is part of Universal Mobile Telecommunications System (UMTS). The third generation partnership project (3 GPP) Long Term Evolution (LTE) is part of evolved UMTS (E-UMTS) using evolved UMTS terrestrial radio access (E-UTRA), and LTE-advanced (a) is an evolved version of 3GPP LTE. The 3GPP New Radio (NR) is a system designed separately from LTE/LTE-a and is a system for supporting enhanced mobile broadband (eMBB), ultra-reliable low-delay communication (URLLC), and large-scale machine type communication (mMTC) services as a requirement of IMT-2020. For clarity of description, the 3GPP NR is mainly described, but the technical ideas of the present invention are not limited thereto.

Unless otherwise specified in the present specification, a base station may refer to a next generation node B (gNB) as defined in 3GPP NR. Further, unless otherwise indicated, a terminal may refer to a User Equipment (UE). Hereinafter, in order to facilitate understanding of the description, each content is individually divided into embodiments and described, but each of the embodiments may be used in combination with each other. In the present disclosure, the configuration of the UE may indicate the configuration by the base station. In particular, the base station may transmit a channel or signal to the UE to configure the operation of the UE or parameter values used in the wireless communication system.

Referring to fig. 1, a radio frame (or radio frame) used in the 3gpp NR system may have a length of 10ms (Δf _maxN_f/100)*T_c). Further, the radio frame includes 10 Subframes (SFs) of equal size. Here ,Δf_max＝480*10³Hz,N_f＝4096,T_c＝1/(Δf_ref*N_f,ref),Δf_ref＝15*10³Hz, and N _f,ref =2048. Numbers from 0 to 9 may be allocated to 10 subframes within one radio frame, respectively. Each subframe is 1ms in length and may include one or more slots according to a subcarrier spacing. More specifically, in the 3GPP NR system, a subcarrier spacing that can be used is 15×2 ^μ kHz, and μ can have values of μ=0, 1,2, 3, 4 as subcarrier spacing configurations. That is, 15kHz, 30kHz, 60kHz, 120kHz, and 240kHz may be used for subcarrier spacing. One subframe of length 1ms may include 2 ^μ slots. In this case, the length of each slot is 2 ^-μ ms. Numbers from 0 to 2 ^μ -1 may be allocated to 2 ^μ slots within one subframe, respectively. In addition, numbers from 0 to 10 x2 ^μ -1 may be allocated to slots within one radio frame, respectively. The time resources may be distinguished by at least one of a radio frame number (also referred to as a radio frame index), a subframe number (also referred to as a subframe index), and a slot number (or slot index).

Fig. 2 illustrates an example of a Downlink (DL)/Uplink (UL) slot structure in a wireless communication system. In particular, fig. 2 shows the structure of a resource grid of a 3GPP NR system.

There is one resource grid per antenna port. Referring to fig. 2, a slot includes a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols in a time domain and a plurality of Resource Blocks (RBs) in a frequency domain. One OFDM symbol also refers to one symbol interval. OFDM symbols may be abbreviated as symbols unless otherwise specified. One RB includes 12 consecutive subcarriers in the frequency domain. Referring to fig. 2, a signal transmitted from each slot may be represented by a resource grid including N ^size,μ _grid,x*N^RB _sc subcarriers and N ^slot _symb OFDM symbols. Here, x=dl when the signal is a DL signal, and x=ul when the signal is an UL signal. N ^size,μ _grid,x denotes the number of Resource Blocks (RBs) according to the subcarrier spacing component μ (x is DL or UL), and N ^slot _symb denotes the number of OFDM symbols in a slot. N ^RB _sc is the number of subcarriers constituting one RB and N ^RB _sc =12. The OFDM symbol may be referred to as a cyclic shift OFDM (CP-OFDM) symbol or a discrete fourier transform spread OFDM (DFT-s-OFDM) symbol according to a multiple access scheme.

The number of OFDM symbols included in one slot may vary according to the length of a Cyclic Prefix (CP). For example, in the case of a normal CP, one slot includes 14 OFDM symbols, but in the case of an extended CP, one slot may include 12 OFDM symbols. In a particular embodiment, extended CP can only be used at 60kHz subcarrier spacing. In fig. 2, one slot is configured with 14 OFDM symbols as an example for convenience of description, but embodiments of the present disclosure may be applied to slots having different numbers of OFDM symbols in a similar manner. Referring to fig. 2, each OFDM symbol includes N ^size,μ _grid,x*N^RB _sc subcarriers in the frequency domain. The types of subcarriers may be divided into data subcarriers for data transmission, reference signal subcarriers for transmission of reference signals, and guard bands. The carrier frequency is also referred to as the center frequency (fc).

One RB may be defined by N ^RB _sc (e.g., 12) consecutive subcarriers in the frequency domain. For reference, a resource configured with one OFDM symbol and one subcarrier may be referred to as a Resource Element (RE) or tone. Thus, one RB can be configured with N ^slot _symb*N^RB _sc resource elements. Each resource element in the resource grid can be uniquely defined by a pair of indices (k, l) in one slot. k may be an index assigned from 0 to N ^size,μ _grid,x*N^RB _sc -1 in the frequency domain, and l may be an index assigned from 0 to N ^slot _symb -1 in the time domain.

For the UE to receive signals from or transmit signals to the base station, the time/frequency of the UE may be synchronized with the time/frequency of the base station. This is because when the base station and the UE are synchronized, the UE can determine time and frequency parameters necessary to demodulate the DL signal at the correct time and transmit the UL signal.

Each symbol of a radio frame used in Time Division Duplex (TDD) or unpaired spectrum may be configured with at least one of a DL symbol, an UL symbol, and a flexible symbol. A radio frame used as a DL carrier in Frequency Division Duplex (FDD) or paired spectrum may be configured with DL symbols or flexible symbols, and a radio frame used as an UL carrier may be configured with UL symbols or flexible symbols. In DL symbols, DL transmission is possible, but UL transmission is not possible. In UL symbols, UL transmission is possible, but DL transmission is not possible. The flexible symbols may be determined to be used as DL or UL according to the signal.

Information about the type of each symbol, i.e., information representing any one of DL symbols, UL symbols, and flexible symbols, may be configured with a cell-specific or common Radio Resource Control (RRC) signal. Furthermore, information about the type of each symbol may be additionally configured with UE-specific or dedicated RRC signals. The base station informs i) a period of a cell-specific slot configuration, ii) a number of slots having only DL symbols from a beginning of the period of the cell-specific slot configuration, iii) a number of DL symbols from a first symbol of a slot immediately after the slot having only DL symbols, iv) a number of slots having only UL symbols from an end of the period of the cell-specific slot configuration, and v) a number of UL symbols from a last symbol of the slot immediately before the slot having only UL symbols, by using a cell-specific RRC signal. Here, the symbol not configured with any one of the UL symbol and the DL symbol is a flexible symbol.

When the information on the symbol type is configured with a UE-specific RRC signal, the base station may signal whether the flexible symbol is a DL symbol or an UL symbol with a cell-specific RRC signal. In this case, the UE-specific RRC signal cannot change the DL symbol or UL symbol configured with the cell-specific RRC signal to another symbol type. The UE-specific RRC signal may signal the number of DL symbols among N ^slot _symb symbols of the corresponding slot and the number of UL symbols among N ^slot _symb symbols of the corresponding slot for each slot. In this case, DL symbols of the slot may be sequentially configured with first to i-th symbols of the slot. Further, the UL symbol of the slot may be successively configured with the j-th symbol through the last symbol of the slot (where i < j). In a slot, a symbol that is not configured with any one of UL symbols and DL symbols is a flexible symbol.

The type of symbol configured with the above RRC signal may be referred to as a semi-static DL/UL configuration. In the semi-static DL/UL configuration previously configured with the RRC signal, the flexible symbols may be indicated as DL symbols, UL symbols, or flexible symbols by dynamic Slot Format Information (SFI) transmitted on a Physical DL Control Channel (PDCCH). In this case, the DL symbol or UL symbol configured with the RRC signal is not changed to another symbol type. Table 1 illustrates dynamic SFIs that a base station can indicate to a UE.

TABLE 1

In table 1, D represents DL symbols, U represents UL symbols, and X represents flexible symbols. As shown in table 1, up to two DL/UL switches may be allowed in one slot.

Fig. 3 is a diagram for explaining physical channels used in a 3GPP system (e.g., NR) and a typical signal transmission method using the physical channels.

If the power of the UE is turned on or the UE camps on a new cell, the UE performs an initial cell search (S101). Specifically, the UE may synchronize with the BS in the initial cell search. To this end, the UE may receive a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) from the base station to synchronize with the base station and obtain information such as a cell ID. Thereafter, the UE can receive a physical broadcast channel from the base station and obtain broadcast information in the cell.

After the initial cell search is completed, the UE receives a Physical Downlink Shared Channel (PDSCH) according to a Physical Downlink Control Channel (PDCCH) and information in the PDCCH, so that the UE can obtain more specific system information than the system information obtained through the initial cell search (S102). Here, the system information received by the UE is cell common system information in Radio Resource Control (RRC) for the UE to operate properly at the physical layer, and is referred to as remaining system information (RSMI) or System Information Block (SIB) 1.

When the UE initially accesses the base station or does not have radio resources for signal transmission (when the UE is in rrc_idle mode), the UE may perform a random access procedure for the base station (operations S103 to S106). First, the UE may transmit a preamble through a Physical Random Access Channel (PRACH) (S103) and receive a Random Access Response (RAR) message for the preamble from the base station through a PDCCH and a corresponding PDSCH (S104). In this case, the preamble in steps S103 and S104 may be described as message 1 (Msg 1), and the random access response may be described as a response message or message 2 (Msg 2). When the UE receives the valid random access response message, the UE transmits data including an identifier of the UE and the like to the base station through a Physical Uplink Shared Channel (PUSCH) indicated by an UL grant transmitted from the base station through the PDCCH (S105). In this case, the data including the own identifier of step S105 and the PUSCH including the data may be described as message 3 (Msg 3). Further, the PUSCH including the data may be described as a message 3PUSCH (Msg 3 PUSCH). Next, the UE waits for reception of PDCCH as an indication of the base station for collision resolution. When the UE successfully receives the PDCCH through its own identifier and receives the corresponding PDSCH (S106), the random access procedure ends. In this case, the PDCCH and PDSCH of step S106 may be described as message 4 (Msg 4). During the random access procedure, the UE may obtain UE-specific system information in the RRC layer that is necessary for the UE to operate properly at the physical layer. When the UE obtains UE-specific system information from the RRC layer, the UE enters an rrc_connected mode.

The RRC layer is used for message generation and management for control between the UE and the Radio Access Network (RAN). More specifically, in the RRC layer, the base station and the UE may perform broadcasting of cell system information, delivery management of paging messages, mobility management and handover, measurement reporting and control thereof, UE capability management, and storage management including existing management necessary for all UEs in a cell. In general, since an update of a signal transmitted from the RRC layer (hereinafter, referred to as an RRC signal) is longer than a transmission/reception period (i.e., transmission time interval, TTI) in the physical layer, the RRC signal can be maintained for a long time.

After the above procedure, the UE receives a PDCCH/PDSCH (S107) and transmits a Physical Uplink Shared Channel (PUSCH)/Physical Uplink Control Channel (PUCCH) (S108) as a general UL/DL signal transmission procedure. In particular, the UE may receive Downlink Control Information (DCI) through the PDCCH. The DCI may include control information such as resource allocation information for the UE. In addition, the format of DCI may vary according to the intended use. Uplink Control Information (UCI) transmitted by a UE to a base station through UL includes DL/UL ACK/NACK signals, channel Quality Indicators (CQIs), precoding Matrix Indexes (PMIs), rank Indicators (RI), and the like. Here, CQI, PMI, and RI may be included in Channel State Information (CSI). In the 3GPP NR system, the UE can transmit control information such as the HARQ-ACK and CSI described above through the PUSCH and/or the PUCCH.

When power is turned on or a new cell is desired to be accessed, the UE may acquire time and frequency synchronization with the cell and perform an initial cell search procedure. The UE may detect the physical cell identity N ^cell _ID of the cell during the cell search procedure. To this end, the UE may receive synchronization signals, e.g., a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS), from the base station and synchronize with the base station. In this case, the UE can obtain information such as a cell Identification (ID).

Referring to fig. 4a, the Synchronization Signal (SS) will be described in more detail. The synchronization signals can be classified into PSS and SSS. The PSS may be used to obtain time domain synchronization and/or frequency domain synchronization, such as OFDM symbol synchronization and slot synchronization. SSS can be used to obtain frame synchronization and cell group ID. Referring to fig. 4a and table 2, the ss/PBCH block can be configured with 20 RBs (=240 subcarriers) in succession on a frequency axis and can be configured with 4 OFDM symbols in succession on a time axis. In this case, in the SS/PBCH block, PSS is transmitted in the first OFDM symbol and SSs is transmitted in the third OFDM symbol through 56 th to 182 th subcarriers. Here, the lowest subcarrier index of the SS/PBCH block is numbered from 0. In the first OFDM symbol in which the PSS is transmitted, the base station transmits no signal through the remaining subcarriers, i.e., the 0 th to 55 th subcarriers and the 183 th to 239 th subcarriers. Further, in the third OFDM symbol in which SSS is transmitted, the base station does not transmit signals through 48 th to 55 th subcarriers and 183 th to 191 th subcarriers. The base station transmits a Physical Broadcast Channel (PBCH) through the remaining REs in the SS/PBCH block except for the above signals.

TABLE 2

The SS allows a total of 1008 unique physical layer cell IDs to be grouped into 336 physical layer cell identifier groups by a combination of three PSS and SSs, each group comprising three unique identifiers, in particular such that each physical layer cell ID will be only part of one physical layer cell identifier group. Thus, the physical layer cell ID N ^cell _ID＝3N⁽¹⁾ _ID+N⁽²⁾ _ID can be uniquely defined by an index N ⁽¹⁾ _ID indicating that the physical layer cell identifier group ranges from 0 to 335 and an index N ⁽²⁾ _ID indicating that the physical layer identifiers in the physical layer cell identifier group range from 0 to 2. The UE may detect the PSS and identify one of three unique physical layer identifiers. Further, the UE can detect the SSS and identify one of 336 physical layer cell IDs associated with the physical layer identifier. In this case, the sequence d _PSS (n) of PSS is as follows.

d_PSS(n)＝1-2x(m)

0≤n＜127

Here, x (i+7) = (x (i+4) +x (i)) mod2 and is given as,

[x(6) x(5) x(4) x(3) x(2) x(1) x(0)]＝[1 1 1 0 1 1 0]。

In addition, the sequence d _SSS (n) of SSS is as follows.

d_SSS(n)＝[1-2x₀((n+m₀)mod127)][1-2x₁((n+m₁)mod127)]

0≤n＜127

Here the number of the elements is the number,And is given as

[x₀(6) x₀(5) x₀(4) x₀(3) x₀(2) x₀(1) x₀(0)]＝[0 0 0 0 0 0 1]

[x₁(6) x₁(5) x₁(4) x₁(3) x₁(2) x₁(1) x₁(0)]＝[0 0 0 0 0 0 1]

A radio frame having a length of 10ms may be divided into two half frames having a length of 5 ms. Referring to fig. 4b, a slot in which an SS/PBCH block is transmitted in each field will be described. The time slot in which the SS/PBCH block is transmitted may be any of cases A, B, C, D and E. In case a, the subcarrier spacing is 15kHz and the starting point in time of the SS/PBCH block is the (2, 8 +14 x n) th symbol. In this case, n=0 or 1 at a carrier frequency of 3GHz or less. Further, at carrier frequencies above 3GHz and below 6GHz, n=0, 1,2,3 may be possible. In case B, the subcarrier spacing is 30kHz and the starting point in time of the SS/PBCH block is {4,8,16,20} +28 x n. In this case, n=0 at a carrier frequency of 3GHz or less. Further, n=0, 1 may be possible at carrier frequencies above 3GHz and below 6 GHz. In case C, the subcarrier spacing is 30kHz and the starting point in time of the SS/PBCH block is the (2, 8 +14 x n) th symbol. In this case, n=0 or 1 at a carrier frequency of 3GHz or less. Further, at carrier frequencies above 3GHz and below 6GHz, n=0, 1,2,3 may be possible. In case D, the subcarrier spacing is 120kHz and the starting point in time of the SS/PBCH block is the ({ 4,8,16,20} +28 x n) th symbol. In this case, n=0, 1,2,3, 5,6,7,8, 10, 11, 12, 13, 15, 16, 17, 18 at a carrier frequency of 6GHz or higher. In case E, the subcarrier spacing is 240kHz and the starting point in time of the SS/PBCH block is the ({ 8,12,16,20,32,36,40,44} +56 x n) th symbol. In this case, n=0, 1,2,3, 5,6,7,8 at a carrier frequency of 6GHz or higher.

Fig. 5a and 5b illustrate a procedure of transmitting control information and a control channel in a 3GPP NR system. Referring to fig. 5a, the base station may add a Cyclic Redundancy Check (CRC) masked (e.g., exclusive or operation) with a Radio Network Temporary Identifier (RNTI) to control information (e.g., downlink Control Information (DCI)) (S202). The base station may scramble the CRC with an RNTI value determined according to the purpose/destination of each control information. The common RNTI used by the one or more UEs can include at least one of a system information RNTI (SI-RNTI), a paging RNTI (P-RNTI), a random access RNTI (RA-RNTI), and a transmit power control RNTI (TPC-RNTI). Further, the UE-specific RNTI may include at least one of a cell temporary RNTI (C-RNTI) and a CS-RNTI. Thereafter, the base station may perform rate matching according to the amount of resources for PDCCH transmission (S206) after performing channel coding (e.g., polarity coding) (S204). Thereafter, the base station may multiplex DCI based on a PDCCH structure based on Control Channel Elements (CCEs) (S208). Further, the base station may apply additional procedures such as scrambling, modulation (e.g., QPSK), interleaving, etc. to the multiplexed DCI (S210), and then map the DCI to the resources to be transmitted. A CCE is a basic resource element for PDCCH, and one CCE may include a plurality of (e.g., six) Resource Element Groups (REGs). One REG may be configured with multiple (e.g., 12) REs. The number of CCEs for one PDCCH may be defined as an aggregation level. In a 3GPP NR system, an aggregation level of 1, 2, 4, 8, or 16 can be used. Fig. 5b is a diagram related to multiplexing of CCE aggregation levels and PDCCHs, and illustrates types of CCE aggregation levels for one PDCCH and CCEs transmitted in a control region according thereto.

CORESET are time-frequency resources in which a PDCCH (i.e., control signals for the UE) is transmitted. In addition, a search space to be described later may be mapped to one CORESET. Thus, the UE may monitor the time-frequency domain designated CORESET instead of monitoring all frequency bands for PDCCH reception and decode the PDCCH mapped to CORESET. The base station may configure the UE with one or more CORESET for each cell. CORESET may be configured with up to three consecutive symbols on the time axis. Further, CORESET may be arranged in units of six consecutive PRBs on the frequency axis. In the embodiment of fig. 5, CORESET #1 is configured with contiguous PRBs, while CORESET #2 and CORESET #3 are configured with non-contiguous PRBs. CORESET can be located in any symbol in the slot. For example, in the embodiment of fig. 5, CORESET #1 starts with the first symbol of the slot, CORESET #2 starts with the fifth symbol of the slot, and CORESET #9 starts with the ninth symbol of the slot.

Fig. 7 illustrates a method for setting a PUCCH search space in a 3GPP NR system.

For transmitting the PDCCH to the UE, each CORESET may have at least one search space. In embodiments of the present disclosure, the search space is a set of all time-frequency resources (hereinafter PDCCH candidates) that can be used to transmit the PDCCH of the UE. The search space may include a common search space that requires UEs of the 3GPP NR to search together and a terminal-specific search space or a UE-specific search space that requires a specific UE to search. In the common search space, UEs may monitor PDCCHs set such that all UEs in a cell belonging to the same base station search in common. Furthermore, a UE-specific search space may be set for each UE such that the UE monitors PDCCHs allocated to each UE at search space positions different according to the UE. In the case of UE-specific search spaces, the search spaces between UEs may be partially overlapped and allocated due to a limited control region in which PDCCHs may be allocated. Monitoring the PDCCH includes blind decoding the PDCCH candidates in the search space. When blind decoding is successful, it may be expressed as (successfully) detecting/receiving a PDCCH, and when blind decoding is failed, it may be expressed as not detecting/not receiving or not successfully detecting/receiving a PDCCH.

For convenience of explanation, a PDCCH scrambled with a Group Common (GC) RNTI previously known to one or more UEs in order to transmit DL control information to the one or more UEs is referred to as a Group Common (GC) PDCCH or a common PDCCH. In addition, a PDCCH scrambled with an RNTI of a specific terminal that the specific UE already knows in order to transmit UL scheduling information or DL scheduling information to the specific UE is referred to as a PDCCH of the specific UE. The common PDCCH may be included in the common search space, and the UE-specific PDCCH may be included in the common search space or the UE-specific PDCCH.

The base station may signal information about resource allocation of a Paging Channel (PCH) and a downlink shared channel (DL-SCH) as transport channels (i.e., DL grant) or information about resource allocation of an uplink shared channel (UL-SCH) and a hybrid automatic repeat request (HARQ) (i.e., UL grant) to each UE or UE group through the PDCCH. The base station may transmit the PCH transport block and the DL-SCH transport block through the PDSCH. The base station may transmit data excluding specific control information or specific service data through the PDSCH. In addition, the UE may receive data excluding specific control information or specific service data through the PDSCH.

The base station may include information on to which UE(s) PDSCH data is transmitted and how the PDSCH data is to be received and decoded by the corresponding UE in the PDCCH, and transmit the PDCCH. For example, assume that DCI transmitted on a specific PDCCH is CRC-masked with RNTI "a" and the DCI indicates that PDSCH is allocated to radio resource "B" (e.g., frequency location) and indicates transport format information "C" (e.g., transport block size, modulation scheme, coding information, etc.). The UE monitors the PDCCH using RNTI information possessed by the UE. In this case, if there is a UE performing blind decoding of the PDCCH using the "a" RNTI, the UE receives the PDCCH and receives PDSCH indicated by "B" and "C" through information of the received PDCCH.

Table 3 shows an embodiment of a Physical Uplink Control Channel (PUCCH) used in a wireless communication system.

TABLE 3

PUCCH format	Length of OFDM symbol	Number of bits
			0	1-2	≤2
1	4-14	≤2
			2	1-2	＞2
3	4-14	＞2
			4	4-14	＞2

The PUCCH may be used to transmit the following UL Control Information (UCI).

-A Scheduling Request (SR): information for requesting UL-SCH resources.

-HARQ-ACK: a response to PDCCH (indicating DL SPS release) and/or a response to DL Transport Block (TB) on PDSCH. The HARQ-ACK indicates whether information transmitted on the PDCCH or PDSCH is received. The HARQ-ACK response includes a positive ACK (abbreviated ACK), a negative ACK (hereinafter NACK), discontinuous Transmission (DTX), or NACK/DTX. Here, the term HARQ-ACK is used in combination with HARQ-ACK/NACK and ACK/NACK. Generally, an ACK may be represented by a bit value of 1, while a NACK may be represented by a bit value of 0.

-Channel State Information (CSI): feedback information about DL channels. The UE generates it based on CSI-Reference Signals (RSs) transmitted by the base station. Multiple Input Multiple Output (MIMO) -related feedback information includes a Rank Indicator (RI) and a Precoding Matrix Indicator (PMI). The CSI can be divided into CSI part 1 and CSI part 2 according to information indicated by the CSI.

In the 3GPP NR system, five PUCCH formats may be used to support various service scenarios, various channel environments, and frame structures.

PUCCH format 0 is a format capable of transmitting 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 0 can be transmitted through one or two OFDM symbols on the time axis and one PRB on the frequency axis. When PUCCH format 0 is transmitted in two OFDM symbols, the same sequence on the two symbols may be transmitted through different RBs. In this case, the sequence may be a Cyclic Shift (CS) sequence from a base sequence for PUCCH format 0. With this, the UE can obtain a frequency diversity gain. Specifically, the UE may determine a Cyclic Shift (CS) value M _cs according to M _bit bits UCI (M _bit =1 or 2). Further, a sequence in which a base sequence of length 12 is cyclically shifted based on a predetermined CS value m _cs may be mapped to 1 OFDM symbol and 12 REs of 1 RB and transmitted. When the number of cyclic shifts available to the UE is 12 and M _bit =1, 1-bit UCI 0 and 1 may be mapped to two cyclic shift sequences having a difference of cyclic shift values of 6, respectively. Further, when M _bit =2, 2 bits UCI 00, 01, 11, and 10 may be mapped to four cyclic shift sequences in which the difference of cyclic shift values is 3, respectively.

PUCCH format 1 may deliver 1-bit or 2-bit HARQ-ACK information or SRs. PUCCH format 1 may be transmitted through consecutive OFDM symbols on the time axis and one PRB on the frequency axis. Here, the number of OFDM symbols occupied by PUCCH format 1 may be one of 4 to 14. More specifically, UCI with M _bit =1 may be BPSK modulated. The UE may modulate UCI with M _bit =2 using Quadrature Phase Shift Keying (QPSK). The signal is obtained by multiplying the modulated complex-valued symbol d (0) by a sequence of length 12. In this case, the sequence may be a base sequence for PUCCH format 0. The UE expands the even-numbered OFDM symbols to which PUCCH format 1 is allocated by a time axis Orthogonal Cover Code (OCC) to transmit the obtained signal. PUCCH format 1 determines the maximum number of different UEs multiplexed in one RB according to the length of OCC to be used. Demodulation reference signals (DMRS) may be extended with OCC and mapped to odd-numbered OFDM symbols of PUCCH format 1.

PUCCH format 2 may deliver UCI over 2 bits. PUCCH format 2 may be transmitted through one or two OFDM symbols on the time axis and one or more RBs on the frequency axis. When PUCCH format 2 is transmitted in two OFDM symbols, sequences transmitted in different RBs through the two OFDM symbols may be identical to each other. Here, the sequence may be a plurality of modulated complex-valued symbols d (0), -d (M _symbol -1). Here, M _symbol may be M _bit/2. Through this, the UE can obtain a frequency diversity gain. More specifically, M _bit bits UCI (M _bit > 2) are bit-level scrambled, QPSK modulated, and mapped to RBs of one or two OFDM symbols. Here, the number of RBs may be one of 1 to 16.

PUCCH format 3 or PUCCH format 4 may deliver UCI exceeding 2 bits. PUCCH format 3 or PUCCH format 4 may be transmitted through consecutive 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 may be one of 4 to 14. Specifically, the UE modulates M _bit bits UCI (M _bit > 2) with e/2-Binary Phase Shift Keying (BPSK) or QPSK to generate complex-valued symbols d (0) to d (M _symb -1). Here, when pi/2-BPSK is used, M _symb＝M_bit, and when QPSK is used, M _symb＝M_bit/2. The UE may not apply block unit extension to PUCCH format 3. However, the UE may apply block unit spreading to one RB (i.e., 12 subcarriers) using PreDFT-OCC of length 12, so that PUCCH format 4 may have two or four multiplexing capabilities. The UE performs transmit precoding (or DFT precoding) on the spread signal and maps it to each RE to transmit the spread signal.

In this case, the number of RBs occupied by PUCCH format 2, PUCCH format 3 or PUCCH format 4 may be determined according to the length of UCI transmitted by the UE and the maximum coding rate. When the UE uses PUCCH format 2, the UE may transmit HARQ-ACK information and CSI information together through the PUCCH. When the number of RBs that the UE can transmit is greater than the maximum number of RBs that the PUCCH format 2, PUCCH format 3, or PUCCH format 4 can use, the UE can transmit only the remaining UCI information without transmitting some UCI information according to the priority of the UCI information.

PUCCH format 1, PUCCH format 3, or PUCCH format 4 may be configured by an RRC signal to indicate frequency hopping in a slot. When frequency hopping is configured, an index of RBs to be frequency hopped can be configured with an RRC signal. When PUCCH format 1, PUCCH format 3, or PUCCH format 4 is transmitted through N OFDM symbols of the time axis, the first hop may have floor (N/2) OFDM symbols and the second hop may have ceiling (N/2) OFDM symbols.

PUCCH format 1, PUCCH format 3, or PUCCH format 4 may be configured to be repeatedly transmitted in a plurality of slots. In this case, the number K of slots in which the PUCCH is repeatedly transmitted may be configured by an RRC signal. The repeatedly transmitted PUCCH must start with an OFDM symbol at a constant position in each slot and have a constant length. When one OFDM symbol among OFDM symbols of a slot in which the UE should transmit the PUCCH is indicated as a DL symbol through an RRC signal, the UE may not transmit the PUCCH in the corresponding slot and delay transmission of the PUCCH to the next slot to transmit the PUCCH.

Meanwhile, in the 3GPP NR system, the UE may perform transmission/reception using a bandwidth less than or equal to that of a carrier (or cell). To this end, the UE may be configured with a bandwidth part (BWP) consisting of a continuous bandwidth of a part of the bandwidth of the carrier. A UE operating according to TDD or in unpaired spectrum may receive up to four DL/UL BWP pairs for one carrier (or cell). In addition, the UE may activate one DL/UL BWP pair. A UE operating according to FDD or operating in a paired spectrum may receive up to 4 DL BWP on a downlink carrier (or cell) and up to 4 UL BWP on an uplink carrier (or cell). The UE may activate one DL BWP and UL BWP for each carrier (or cell). The UE may not receive or transmit in time-frequency resources other than the activated BWP. The activated BWP may be referred to as an active BWP.

The base station may indicate an activated BWP among BWPs configured by the UE through Downlink Control Information (DCI). BWP indicated by DCI is activated and BWP of other configuration is deactivated. In a carrier (or cell) operating in TDD, a base station may include a Bandwidth Part Indicator (BPI) indicating an activated BWP in DCI scheduling PDSCH or PUSCH to change a DL/UL BWP pair of a UE. The UE may receive DCI scheduling PDSCH or PUSCH and may identify an activated DL/UL BWP pair based on BPI. In case of a downlink carrier (or cell) operating in FDD, the base station may include a BPI indicating an activated BWP in DCI of the scheduled PDSCH to change the DL BWP of the UE. In the case of an uplink carrier (or cell) operating in FDD, the base station may include a BPI indicating an activated BWP in DCI of the scheduled PUSCH to change UL BWP of the UE.

Fig. 8 is a conceptual diagram illustrating carrier aggregation.

Carrier aggregation is a method in which a UE uses a plurality of frequency blocks or (in a logical sense) cells configured with UL resources (or component carriers) and/or DL resources (or component carriers) as one large logical band in order for a wireless communication system to use a wider frequency band. One component carrier may also be referred to as a term called primary cell (PCell) or secondary cell (SCell) or primary SCell (PScell). Hereinafter, however, for convenience of description, the term "component carrier" is used.

Referring to fig. 8, as an example of the 3GPP NR system, the entire system band may include at most 16 component carriers, and each component carrier may have a bandwidth of at most 400 MHz. The component carriers may include one or more physically contiguous subcarriers. Although each component carrier is shown in fig. 8 as having the same bandwidth, this is merely an example, and each component carrier may have a different bandwidth. In addition, although each component carrier is shown as being adjacent to each other on the frequency axis, the drawing is logically shown, and each component carrier may be physically adjacent to each other or may be spaced apart.

A different center frequency may be used for each component carrier. In addition, one common center frequency may be used in physically adjacent component carriers. Assuming that all component carriers are physically adjacent in the embodiment of fig. 8, the center frequency a may be used in all component carriers. In addition, the center frequency a and the center frequency B can be used in each component carrier, assuming that the respective component carriers are not physically adjacent to each other.

When the total system band is extended by carrier aggregation, a band for communication with each UE can be defined in units of component carriers. UE a may use 100MHz as a total system band and perform communication using all five component carriers. UE B ₁～B₅ can perform communication using only a 20MHz bandwidth and using one component carrier. UE C ₁ and C ₂ may perform communication using a 40MHz bandwidth and using two component carriers, respectively. The two component carriers may or may not be logically/physically contiguous. UE C ₁ represents a case where two non-adjacent component carriers are used, and UE C ₂ represents a case where two adjacent component carriers are used.

Fig. 9 is a diagram for explaining single carrier communication and multi-carrier communication. In particular, fig. 9 (a) shows a single carrier subframe structure and fig. 9 (b) shows a multi-carrier subframe structure.

Referring to fig. 9 (a), in the FDD mode, a general wireless communication system may perform data transmission or reception through one DL frequency band and one UL frequency band corresponding thereto. In another particular embodiment, in TDD mode, the wireless communication system may divide a radio frame into UL time units and DL time units in the time domain and perform data transmission or reception through the UL/DL time units. Referring to fig. 9 (b), three 20MHz Component Carriers (CCs) can be aggregated into each of UL and DL so that a bandwidth of 60MHz can be supported. Each CC may or may not be adjacent to each other in the frequency domain. Fig. 9 (b) shows a case where the bandwidth of the UL CC and the bandwidth of the DL CC are the same and symmetrical, but the bandwidth of each CC can be independently determined. Furthermore, asymmetric carrier aggregation with different numbers of UL CCs and DL CCs is possible. DL/UL CCs allocated/configured to a specific UE through RRC may be referred to as serving DL/UL CCs of the specific UE.

The base station may perform communication with the UE by activating some or all of the serving CCs of the UE or disabling some CCs. The base station can change CCs to be activated/deactivated and change the number of CCs to be activated/deactivated. If the base station allocates CCs available to the UE as cell-specific or UE-specific, at least one of the allocated CCs will not be deactivated unless the CC allocation for the UE is completely reconfigured or the UE is switched. One CC that is not deactivated by the UE is referred to as a primary CC (PCC) or primary cell (PCell), and a CC that the base station can freely activate/deactivate is referred to as a secondary CC (SCC) or secondary cell (SCell).

Meanwhile, 3GPP NR manages radio resources using the concept of a cell. A cell is defined as a combination of DL resources and UL resources, i.e., a combination of DL CCs and UL CCs. A cell may be configured with DL resources alone or may be configured with a combination of DL and UL resources. When carrier aggregation is supported, a link between a carrier frequency of a DL resource (or DL CC) and a carrier frequency of a UL resource (or UL CC) may be indicated by system information. The carrier frequency refers to the center frequency of each cell or CC. The cell corresponding to the PCC is referred to as PCell, and the cell corresponding to the SCC is referred to as SCell. The carrier corresponding to the PCell in DL is DL PCC and the carrier corresponding to the PCell in UL is UL PCC. Similarly, the carrier in DL corresponding to SCell is DL SCC, and the carrier in UL corresponding to SCell is UL SCC. Depending on the UE capabilities, the serving cell may be configured with one PCell and zero or more scells. In the case of a UE in the rrc_connected state but not configured for carrier aggregation or not supporting carrier aggregation, only one serving cell is configured with only PCell.

As described above, the term "cell" used in carrier aggregation is distinguished from the term "cell" which refers to a certain geographical area where communication services are provided through one base station or one antenna group. That is, one component carrier may also be referred to as a scheduling cell, a scheduled cell, a primary cell (PCell), a secondary cell (SCell), or a primary SCell (PScell). However, in order to distinguish between a cell representing a certain geographical area and a carrier aggregated cell, in the present disclosure, the carrier aggregated cell is referred to as a CC, and the cell of the geographical area is referred to as a cell.

Fig. 10 is a diagram showing an example in which a cross-carrier scheduling technique is applied. When the cross-carrier scheduling is set, a control channel transmitted through the first CC may schedule a data channel transmitted through the first CC or the second CC using a Carrier Indicator Field (CIF). CIF is included in DCI. In other words, a scheduling cell is set, and DL grant/UL grant transmitted in the PDCCH region of the scheduling cell schedules PDSCH/PUSCH of the cell to be scheduled. That is, there is a search region for a plurality of component carriers in the PDCCH region of the scheduling cell. The PCell may basically be a scheduling cell, and a specific SCell may be designated as a scheduling cell by an upper layer.

In the embodiment of fig. 10, it is assumed that three DL CCs are combined. Here, it is assumed that DL component carrier #0 is DL PCC (or PCell), and DL component carrier #1 and DL component carrier #2 are DL SCCs (or scells). Further, it is assumed that DL PCC is set as PDCCH monitoring CC. When cross-carrier scheduling is not configured by UE-specific (or UE group-specific or cell-specific) higher layer signaling, CIF is disabled and each DL CC can transmit only PDCCH for scheduling its PDSCH without CIF according to NR PDCCH rules (non-cross-carrier scheduling, self-carrier scheduling). Meanwhile, if cross-carrier scheduling is configured through UE-specific (or UE group-specific or cell-specific) higher layer signaling, CIF is enabled, and a specific CC (e.g., DL PCC) may use CIF to transmit not only PDCCH for scheduling PDSCH of DL CC a but also PDCCH for scheduling PDSCH of another CC (cross-carrier scheduling). On the other hand, the PDCCH is not transmitted in another DL CC. Thus, the UE monitors the PDCCH including no CIF to receive the PDSCH from the carrier schedule according to whether the UE is configured with the cross-carrier schedule or monitors the PDCCH including CIF to receive the PDSCH of the cross-carrier schedule.

On the other hand, fig. 9 and 10 illustrate subframe structures of the 3GPP LTE-a system, and the same or similar configuration may be applied to the 3GPP NR system. However, in the 3GPP NR system, the subframes of fig. 9 and 10 may be replaced with slots.

In embodiments of the present disclosure, a UE may be implemented with various types of wireless communication devices or computing devices that are guaranteed to be portable and mobile. A UE may be referred to as a User Equipment (UE), a Station (STA), a Mobile Subscriber (MS), etc. Further, in the embodiments of the present disclosure, the base station controls and manages cells (e.g., macro cells, femto cells, pico cells, etc.) corresponding to the service area, and performs functions of signal transmission, channel assignment, channel monitoring, self diagnosis, relay, etc. A base station may be referred to as a next generation node B (gNB) or an Access Point (AP).

As shown in the drawings, the UE 100 according to an embodiment of the present disclosure may include a processor 110, a communication module 120, a memory 130, a user interface 140, and a display unit 150.

First, the processor 110 may execute various instructions or processes and process data within the UE 100. Further, the processor 110 may control the overall operation of each unit including the UE 100, and may control transmission/reception of data between the units. Here, the processor 110 may be configured to perform operations according to embodiments described in the present disclosure. For example, the processor 110 may receive slot configuration information, determine a slot configuration based on the slot configuration information, and perform communication according to the determined slot configuration.

Next, the communication module 120 may be an integrated module that performs wireless communication using a wireless communication network and performs wireless LAN access using a wireless LAN. To this end, the communication module 120 may include a plurality of Network Interface Cards (NICs) such as cellular communication interface cards 121 and 122 and unlicensed band communication interface card 123 in an internal or external form. In the drawings, the communication module 120 is shown as a unitary integrated module, but unlike the drawings, each network interface card can be independently arranged according to a circuit configuration or usage.

The cellular communication interface card 121 may transmit or receive a radio signal with at least one of the base station 200, an external device, and a server by using a mobile communication network and provide a cellular communication service in a first frequency band based on an instruction from the processor 110. According to an embodiment, cellular communication interface card 121 may include at least one NIC module that uses a frequency band less than 6 GHz. At least one NIC module of the cellular communication interface card 121 may independently perform cellular communication with at least one of the base station 200, the external device, and the server in accordance with a cellular communication standard or protocol in a frequency band below 6GHz supported by the corresponding NIC module.

The cellular communication interface card 122 may transmit or receive a radio signal with at least one of the base station 200, an external device, and a server by using a mobile communication network and provide a cellular communication service in a second frequency band based on an instruction from the processor 110. According to an embodiment, cellular communication interface card 122 may include at least one NIC module that uses a frequency band greater than 6 GHz. At least one NIC module of the cellular communication interface card 122 may independently perform cellular communication with at least one of the base station 200, the external device, and the server in accordance with a cellular communication standard or protocol in a frequency band of 6GHz or more supported by the corresponding NIC module.

The unlicensed band communication interface card 123 transmits or receives radio signals with at least one of the base station 200, the external device, and the server by using a third frequency band that is an unlicensed band, and provides unlicensed band communication services based on instructions from the processor 110. The unlicensed band communication interface card 123 may include at least one NIC module that uses unlicensed bands. For example, the unlicensed frequency band may be a frequency band of 2.4GHz, 5GHz, 6GHz, 7GHz, or above 52.6 GHz. The at least one NIC module of the unlicensed band communication interface card 123 may perform wireless communication with at least one of the base station 200, the external device, and the server independently or in dependence according to unlicensed band communication standards or protocols of the frequency bands supported by the corresponding NIC module.

The memory 130 stores a control program used in the UE 100 and various data used therefor. Such a control program may include a prescribed program required to perform wireless communication with at least one of the base station 200, an external device, and a server.

Next, the user interface 140 includes various input/output means provided in the UE 100. In other words, the user interface 140 may receive user input using various input means, and the processor 110 may control the UE 100 based on the received user input. Further, the user interface 140 may use various output means to perform output based on instructions from the processor 110.

Next, the display unit 150 outputs various images on the display screen. The display unit 150 may output various display objects, such as content or a user interface executed by the processor 110, based on control instructions from the processor 110.

Further, the base station 200 according to the embodiments of the present disclosure may include a processor 210, a communication module 220, and a memory 230.

First, the processor 210 may execute various instructions or programs and process internal data of the base station 200. Further, the processor 210 may control the overall operation of the units in the base station 200 and control the transmission and reception of data between the units. Here, the processor 210 may be configured to perform operations according to embodiments described in the present disclosure. For example, the processor 210 may signal a slot configuration and perform communication according to the signaled slot configuration.

Next, the communication module 220 may be an integrated module that performs wireless communication using a wireless communication network and performs wireless LAN access using a wireless LAN. To this end, the communication module 220 may include a plurality of network interface cards, such as cellular communication interface cards 221 and 222 and unlicensed band communication interface card 223, in an internal or external form. In the drawings, the communication module 220 is shown as a unitary integrated module, but unlike the drawings, each network interface card can be independently arranged according to a circuit configuration or usage.

The cellular communication interface card 221 may transmit or receive a radio signal with at least one of the base station 100, an external device, and a server by using a mobile communication network and provide a cellular communication service in a first frequency band based on an instruction from the processor 210. According to an embodiment, the cellular communication interface card 221 may include at least one NIC module using a frequency band less than 6 GHz. At least one NIC module of the cellular communication interface card 221 may independently perform cellular communication with at least one of the base station 100, the external device, and the server in accordance with a cellular communication standard or protocol in a frequency band of less than 6GHz supported by the corresponding NIC module.

The cellular communication interface card 222 may transmit or receive radio signals with at least one of the base station 100, an external device, and a server by using a mobile communication network and provide cellular communication services in a second frequency band based on instructions from the processor 210. According to an embodiment, the cellular communication interface card 222 may include at least one NIC module using a frequency band of 6GHz or higher. At least one NIC module of the cellular communication interface card 222 may independently perform cellular communication with at least one of the base station 100, the external device, and the server in accordance with a cellular communication standard or protocol in a frequency band of 6GHz or higher supported by the corresponding NIC module.

The unlicensed band communication interface card 223 transmits or receives radio signals with at least one of the base station 100, the external device, and the server by using a third frequency band that is an unlicensed band, and provides unlicensed band communication services based on instructions from the processor 210. The unlicensed band communication interface card 223 may include at least one NIC module that uses unlicensed bands. For example, the unlicensed frequency band may be a frequency band of 2.4GHz, 5GHz, 6GHz, 7GHz, or above 52.6 GHz. The at least one NIC module of the unlicensed band communication interface card 223 may perform wireless communication with at least one of the base station 100, the external device, and the server independently or in dependence according to unlicensed band communication standards or protocols of the frequency bands supported by the corresponding NIC module.

Fig. 11 is a block diagram illustrating a UE 100 and a base station 200 according to an embodiment of the present disclosure, and the blocks shown separately are logically divided elements of an apparatus. Thus, the aforementioned elements of the device may be mounted in a single chip or multiple chips depending on the design of the device. Further, a portion of the configuration of the UE 100, e.g., the user interface 140, the display unit 150, etc., may be selectively provided in the UE 100. Furthermore, a user interface 140, a display unit 150, etc. may be additionally provided in the base station 200 as necessary.

Fig. 12 illustrates a method of scheduling a physical uplink shared channel in the time domain according to an embodiment of the present disclosure.

The terminal may transmit uplink data to the base station through the PUSCH. The base station may schedule (PUSCH schedule) for the terminal to transmit uplink data through the PUSCH. i) In a Dynamic Grant (DG) method, a base station may perform PUSCH scheduling via DCI included in a PDCCH. Alternatively, ii) in the Configuration Grant (CG) method, the terminal may transmit uplink data to the base station through PUSCH according to resources and transmission methods preconfigured for the terminal by the base station.

In this case, DCI included in the PDCCH may include PUSCH scheduling information. For example, the DCI may include time domain information (time domain resource assignment (TDRA)) and frequency domain information (frequency domain resource assignment (FDRA)). The terminal may receive DCI transmitted in the control resource set and the search space, and may perform an operation indicated via the DCI (e.g., uplink data transmission through PUSCH). In this case, DCI formats for PUSCH scheduling may be DCI formats 0_0, 0_1, and 0_2. The DCI of DCI formats 0_0, 0_1, and 0_2 may include TDRA fields containing time domain information of PUSCH. In this case, the time domain information may include K2, which is an offset value between a slot in which the PDCCH is transmitted from the base station and a slot in which the PUSCH is transmitted by the terminal. In addition, the DCI may include a Start and Length Indication Value (SLIV) which is a joint coding value of a start symbol index (S) of PUSCH and a symbol length (L, number) of PUSCH in a slot indicated by K2. If the terminal receives DCI in slot n, the slot in which PUSCH is scheduled may be floor (n× ^μPUSCH/n*2^μPDCCH) +k2 slot. The μpusch and μpdcch may refer to a subcarrier spacing of a cell in which the PUSCH is scheduled and a subcarrier spacing (SCS) of a cell in which the terminal receives the PDCCH, respectively. floor (x) is a function that returns the largest integer among integers equal to or smaller than x. In this specification, a slot n may refer to a slot indexed with an index n.

Referring to (a) of fig. 12, the subcarrier spacing of a cell in which the terminal receives the PDCCH and the subcarrier spacing of a cell in which the PUSCH is scheduled may be the same. In this case, if the terminal receives the PDCCH in the slot n and is instructed that K2 is 4, the slot in which the PUSCH is scheduled may be the slot n+k2, i.e., the slot n+4.

As for the PUSCH scheduling type, there may be two mapping types of PUSCH mapping type a and PUSCH mapping type B. Depending on the PUSCH mapping type, the starting symbol index for PUSCH and the range of possible values for SLIV may vary. In PUSCH mapping type a, resource allocation including only DMRS symbols is possible, and the DMRS symbols may be located in the third or fourth symbol of the slot according to a value indicated by a higher layer. That is, in case of PUSCH mapping type a, the index (S) of the start symbol of PUSCH may be 0, and the length (L) of PUSCH may have one of values from 4 to 14 (12 for extended CP) according to DMRS symbol positions. In PUSCH mapping type B, the first symbol of PUSCH may be a DMRS symbol. Thus, S may have a value from 0 to 13 (11 for extended CP), and L may have one of a value from 1 to 14 (12 for extended CP). In addition, since one PUSCH cannot cross a slot boundary, the sum of S and L should be less than or equal to 14 (12 for extended CP).

Referring to (B) of fig. 12, the base station may schedule a PUSCH mapping type a in which the third symbol is a DMRS symbol, the index (S) of the start symbol is 0, and the length (L) is 7, may schedule a PUSCH mapping type a in which the fourth symbol is a DMRS symbol, the index (S) of the start symbol is 0, and the length (L) is 7, and may schedule a PUSCH mapping type B in which the first symbol is a DMRS symbol, the index (S) of the start symbol is 5, and the length (L) is 5. In this case, frequency domain information of PUSCH indicated in FDRA field of DCI format 0_0, 0_1 or 0_2 may be divided into two types according to frequency resource allocation type.

Fig. 13 illustrates a method of scheduling a physical uplink shared channel in the frequency domain according to an embodiment of the present disclosure.

Hereinafter, a frequency resource allocation type will be described with reference to fig. 13.

I) The frequency resource allocation type 0 as the first type may be a type that configures RBGs by bundling a certain number of PRBs according to the number of RBs included in BWP configured (set) for the terminal and indicates whether to use the RBGs via a bitmap in units of the RBGs. That is, the terminal can determine whether to use the corresponding RBG via the bitmap transmitted from the base station. The number of PRBs included in one RBG may be set (configured) from a higher layer, and as the number of RBs included in BWP set (configured) for a terminal is greater, the number of PRBs may be set (configured) more. Referring to (a) of fig. 13, a BWP size set (configured) for a terminal may be 72 PRBs, and one RBG may include 4 PRBs. In this case, the terminal may determine four PRBs as one RBG in ascending order from PRB 0, and may index each RBG from 0. That is, RBGs including PRB 0 through PRB 3 may be indexed as RBG 0, and RBGs including PRB 4 through PRB 7 may be indexed as RBG 1. Until the RBGs 17 can be indexed in the same manner, wherein the base station can transmit 1 bit (0 or 1) per RBG to the terminal, i.e., 18 bits in total, and the terminal can determine whether to use PRBs constituting the corresponding RBG based on the received 18 bits. In this case, if the bit value is 0, the terminal may determine not to schedule PUSCH for any PRB among PRBs constituting the corresponding RBG. If the bit value is 1, the terminal may determine to schedule PUSCH for all PRBs in the corresponding RBG. In this case, the bit values may be applied in reverse. ii) the frequency resource allocation type 1 as the second type may be a type indicating information on consecutive PRBs allocated according to the size of the active BWP or the initial BWP of the terminal. The information on the consecutive PRBs may be a Resource Indication Value (RIV) in which a start index (S) and a length (L) of the consecutive PRBs are jointly encoded. Referring to (b) of fig. 13, when the BWP size is 50 PRBs and PUSCH is scheduled for a terminal from PRB 2 to PRB 11 among the 50 PRBs, a start index of consecutive PRBs may be 2 and a length may be 10. That is, the terminal may determine a starting index and a length of consecutive PRBs in which to schedule PUSCH based on the RIV value received from the base station. Specifically, RIV can be calculated from N ^size _BWP x (L-1) +S. N ^size _BWP may be the size of BWP configured for the terminal. For example, if the RIV value received by the terminal is 452, calculation of 452 is based on 452=50×10-1) +2, so the terminal can determine that the starting index of the consecutive PRBs in which PUSCH is scheduled is 2 and the length is 10.

Via DCI of DCI format 0_1 or 0_2 for scheduling PUSCH, a terminal may be configured from a higher layer to use only one of the aforementioned two frequency resource allocation types or to dynamically use both types. If the terminal is configured to dynamically use both types, the terminal may determine the type to use via 1 bit of the Most Significant Bit (MSB) of FDRA field of DCI.

There may be an uplink shared channel transmission method or the like based on a configuration grant for URLLC transmission. The uplink shared channel transmission method based on the configuration grant may be described as unlicensed transmission. The configuration grant-based uplink shared channel transmission method may be a method in which, if the base station configures available resources for uplink transmission for the terminal via a higher layer (i.e., RRC signaling), the terminal can transmit the uplink shared channel by using the configured resources. Uplink shared channel transmission methods based on configuration grants can be classified into two types depending on whether DCI indicates activation and release. i) Type 1 of the uplink shared channel transmission method based on the configuration grant may be a method of configuring a transmission method and resources in advance via a higher layer. ii) type 2 of the configuration grant based uplink shared channel transmission method may be a method of configuring a configuration grant based transmission via a higher layer and configuring a method and resources for an actual transmission via DCI.

The uplink transmission method based on the configuration grant may support URLLC transmission. Accordingly, uplink transmission can be repeatedly performed over a plurality of slots to ensure high reliability. In this case, the Redundancy Version (RV) sequence may be one of {0, 0}, {0,2,3,1} and {0,3,0,3}, and an RV corresponding to the (mod (n-1, 4) +1) th value may be used in the nth retransmission. That is, RV corresponding to a value obtained by adding 1 to the remainder of dividing n-1 by 4 may be used. In addition, a terminal configured to repeatedly transmit an uplink channel may start repeating transmission only in a slot having an RV value of 0. However, if the RV sequence is {0, 0} and the uplink channel is configured to be repeatedly transmitted in 8 slots, the terminal may not start repeated transmission in the eighth slot. The terminal may terminate the repeated transmission when receiving UL grant with the same HARQ process ID, or when reaching the number of repeated transmissions configured via higher layers or exceeding a period. UL grant may refer to DCI for PUSCH scheduling.

As described above, in order to improve PUSCH transmission/reception reliability between a base station and a terminal in a wireless communication system, the base station may configure the terminal to repeatedly transmit PUSCH.

Fig. 14 illustrates repeated transmission of a physical uplink shared channel according to an embodiment of the present disclosure.

The repeated PUSCH transmission performed by the terminal may be of two types. i) First, the repeated PUSCH transmission type a will be described. When the terminal receives DCI of DCI format 0_1 or 0_2 included in PDCCH for PUSCH scheduling from the base station, the terminal may repeatedly transmit PUSCH on K consecutive slots. The K value may be configured from a higher layer or may be a value included in TDRA field of DCI to configure a terminal. For example, referring to fig. 14 (a), a terminal may receive a PDCCH for PUSCH scheduling in a slot n, and may configure a K2 value according to DCI included in the received PDCCH. In this case, if the K2 value is 2 and the K value is 4, the terminal may start repeating PUSCH transmission in the slot n+k2 and may repeatedly transmit PUSCH until the slot n+k2+k-1. That is, the terminal starts to repeat PUSCH transmission in slot n+2 and repeatedly transmits PUSCH until slot n+5. In this case, the time domain resources and frequency domain resources of the PUSCH transmitted in each slot may be the same as those indicated in the DCI. That is, PUSCH may be transmitted in the same symbol and PRB within a slot. ii) next, the repeated PUSCH transmission type B will be described. The repeated PUSCH transmission type B may be a type for a terminal to perform low latency repeated PUSCH transmissions in order to meet URLLC requirements, etc. The terminal may be configured with a symbol (S) for repeating PUSCH transmission start and a length (L) for repeating PUSCH transmission via TDRA field of DCI transmitted by the base station. In this case, the start symbol (S) and the length (L) may be for a nominal PUSCH obtained temporarily instead of an actual PUSCH actually transmitted by the terminal. There may be no separate symbols between nominal PUSCHs configured to be repeatedly transmitted. That is, the nominal PUSCH may be continuous in the time domain. The terminal may determine the actual PUSCH from the nominal PUSCH. One nominal PUSCH may be determined as one or more actual PUSCHs. The base station may configure the terminal with symbols that are not available for repetition of PUSCH transmission type B. Symbols that are not available for repeated PUSCH transmission type B may be described as invalid symbols. The terminal may exclude invalid symbols from among the resources configured to transmit the nominal PUSCH. As described above, the nominal PUSCH is configured to be repeatedly transmitted on consecutive symbols, but if an invalid symbol is excluded, the resources for the nominal PUSCH transmission become discontinuous. The actual PUSCH may be configured to be transmitted on consecutive symbols configured for one nominal PUSCH transmission, except for invalid symbols. In this case, if consecutive symbols cross slot boundaries, the actual PUSCH actually transmitted may be divided based on the slot boundaries. The invalid symbols may include downlink symbols configured by the base station for the terminal. Referring to fig. 14 (B), a terminal may be scheduled with PUSCH transmission of length 5 symbols starting from the twelfth symbol of the first slot (slot n), and may be configured with 4 type B repeated transmissions. In this case, the resources scheduled for the first nominal PUSCH (nominal # 1) may include a symbol (n, 11), a symbol (n, 12), a symbol (n, 13), a symbol (n+1, 0), and a symbol (n+1, 1). The resources scheduled for the second nominal PUSCH (nominal # 2) may include symbol (n+1, 2), symbol (n+1, 3), symbol (n+1, 4), symbol (n+1, 5), and symbol (n+1, 6). The resources scheduled for the third nominal PUSCH (nominal # 3) may include symbol (n+1, 7), symbol (n+1, 8), symbol (n+1, 9), symbol (n+1, 10), and symbol (n+1, 11). The resources scheduled for the fourth nominal PUSCH (nominal # 4) may include symbol (n+1, 12), symbol (n+1, 13), symbol (n+2, 0), symbol (n+2, 1), and symbol (n+2, 2). In this case, the symbol (n, k) represents the symbol k of the slot n. That is, k may be a value from 0 to 13 for a normal CP and from 0 to 11 for an extended CP. The invalid symbols may be configured as symbols 6 and 7 of slot n + 1. In this case, in order to determine the actual PUSCH, the last symbol of the second nominal PUSCH (nominal # 2) may be excluded, and the first symbol of the third nominal PUSCH (nominal # 3) may be excluded. The first nominal PUSCH (nominal # 1) may be divided into two actual PUSCHs (actual #1 and actual # 2) actually transmitted by a slot boundary. Each of the second nominal PUSCH (nominal # 2) and the third nominal PUSCH (nominal # 3) may be distinguished into one actual PUSCH (actual #3 and actual # 4) by combining consecutive symbols other than the null symbol. Finally, the fourth nominal PUSCH (nominal # 4) is divided into two actually transmitted (actual) PUSCHs (actual #5 and actual # 6) by slot boundaries. The terminal finally transmits the actually transmitted (actual) PUSCH. One actual PUSCH should include at least one DMRS symbol. Therefore, when the repeated PUSCH transmission type B is configured, if the total length of the actual PUSCH is one symbol, the actual PUSCH may be omitted without being transmitted. This is because the actual PUSCH with one symbol may not include information other than the DMRS.

In order to obtain diversity gain in the frequency domain, frequency hopping may be configured for uplink channel transmission.

For the repeated PUSCH transmission type a, one of intra-slot hopping, in which hopping is performed in slots, and inter-slot hopping, in which hopping is performed in each slot, may be configured for the terminal. If the terminal is configured with intra-slot frequency hopping, the terminal may divide the PUSCH into two in the time domain and transmit one half of the PUSCH in the scheduled PRB in the slot for transmitting the PUSCH, and may transmit the other half in the PRB obtained by adding the offset value to the scheduled PRB. In this case, two or four offset values may be configured according to the active BWP size via a higher layer, and one of the values may be configured (indicated to the configuration) for the terminal via DCI. If inter-slot frequency hopping is configured for a terminal, the terminal may transmit a PUSCH in a scheduled PRB in a slot having an even slot index, and may transmit a PUSCH in a PRB obtained by adding an offset value to the scheduled PRB in an odd slot.

For the repeated PUSCH transmission type B, the terminal may be configured with one of inter-repetition hopping, which performs hopping at a nominal PUSCH boundary, and inter-slot hopping, which performs hopping in each slot. If the terminal is configured with inter-repetition frequency hopping, the terminal may transmit an actual PUSCH corresponding to an odd-numbered nominal PUSCH on a scheduled PRB, and the terminal may transmit an actual PUSCH corresponding to an even-numbered nominal PUSCH on a PRB obtained by adding an offset value to the scheduled PRB. In this case, two or four offset values may be configured according to the active BWP size via a higher layer, and one of the values may be configured (indicated to the configuration) for the terminal via DCI. If inter-slot frequency hopping is configured for a terminal, the terminal may transmit a PUSCH in a scheduled PRB in a slot having an even slot index, and may transmit a PUSCH in a PRB obtained by adding an offset value to the scheduled PRB in an odd slot.

When a terminal performs repeated PUSCH transmission, if a symbol scheduled for PUSCH transmission in a specific slot overlaps with a DL symbol semi-statically configured or a symbol configured to receive SS/PBCH blocks, the terminal may not transmit the overlapping PUSCH on a slot including the overlapping symbol. In addition, the overlapping PUSCH may be delayed and may not be transmitted even on subsequent slots.

If the terminal receives DCI of DCI format 1_0, 1_1 or 1_2 for PUCCH scheduling, the terminal needs to transmit PUCCH to the base station. In this case, the PUCCH may include Uplink Control Information (UCI), and the UCI may include at least one of HARQ-ACK, scheduling Request (SR), and Channel State Information (CSI). The HARQ-ACK may be a HARQ-ACK indicating whether the terminal has successfully received both types of channels. The first type may be HARQ-ACK for PDSCH when the terminal is scheduled with PDSCH via DCI of DCI format 1_0, 1_1 or 1_2. The second type may be HARQ-ACK for DCI when DCI of DCI format 1_0, 1_1 or 1_2 is DCI indicating release of semi-persistently scheduled (SPS) PDSCH. For PUCCH transmission including HARQ-ACK, the PDSCH-to-harq_feedback timing indicator field of DCI may indicate K1, which is information (value) of a slot in which the scheduled PUCCH is transmitted. Here, K1 may be a non-negative integer value. The DCI of DCI format 1_0 may indicate one of {0,1,2,3,4,5,6,7} as a K1 value. The K1 value that can be indicated in the DCI of the DCI format 1_1 or 1_2 may be set (configured) from a higher layer.

A method of determining a slot in which a PUCCH including a first type HARQ-ACK is transmitted will be described. There may be an uplink slot overlapping with the last symbol in which the PDSCH corresponding to the HARQ-ACK is transmitted. In this case, if the index of the overlapping uplink slot is m, the terminal may transmit a PUCCH including HARQ-ACK on slot m+k1. The index of the uplink slot may be a value determined based on a subcarrier interval of BWP in which the PUCCH is transmitted. If the terminal is configured with downlink slot aggregation, the last symbol in which the PDSCH is transmitted may refer to the last scheduled symbol within the last slot among the slots in which the PDSCH is transmitted.

Fig. 15 illustrates a method of scheduling physical uplink control channels according to an embodiment of the present disclosure.

Referring to fig. 15, a subcarrier interval of DL BWP in which a PDCCH is received, a subcarrier interval of DL BWP scheduled for a PDSCH, and a subcarrier interval of UL BWP in which a PUCCH is transmitted may be the same. The terminal may receive a PDCCH for scheduling PUCCH and PDSCH from the base station in slot n. In this case, the K0 value and the K1 value may be configured (indicated) as 2 and 3, respectively, through DCI included in a PDCCH received in a slot. For example, if the last symbol in which the PDSCH is transmitted is the symbol n+k0 (i.e., symbol n+2), the terminal may transmit the HARQ-ACK for the PDSCH on the slot n+2+k1 (i.e., slot n+5). In this case, HARQ-ACK for PDSCH may be included in PUCCH.

Fig. 16 illustrates repeated transmission of a physical uplink control channel according to an embodiment of the present disclosure.

In order to guarantee wide coverage in the NR system, a terminal may repeatedly transmit a long PUCCH on 2,4, or 8 slots. In this case, the format of the long PUCCH may be PUCCH format 1, 3 or 4. If the terminal repeatedly transmits the PUCCH, the same UCI may be repeatedly transmitted in each slot. Referring to fig. 16, when PDSCH reception is terminated in slot n and the K1 value is 2, the terminal may transmit PUCCH on slot n+k1 (i.e., slot n+2). When the base station configures the number of repetition PUCCH transmission to 4 (N ^repeat _PUCCH =4), the terminal may repeatedly transmit PUCCH from slot n+2 to slot n+5. In this case, the symbol configuration of the repeatedly transmitted PUCCH may be the same. That is, the repeatedly transmitted PUCCHs may start from the same symbol in each slot and may include the same number of symbols.

Even for PUCCH transmission, frequency hopping may be applied to obtain diversity gain in the frequency domain. If intra-slot frequency hopping is applied, the terminal may divide the time domain of the slot for transmitting the PUCCH in half and transmit one half of the PUCCH on the first PRB, and may transmit the other half of the PUCCH on the second PRB. The first PRB and the second PRB may be configured via a higher layer for configuration of PUCCH resources. If inter-slot frequency hopping is applied, the terminal may transmit the PUCCH on a first PRB of a slot having an even slot index and may transmit the PUCCH on a second PRB of a slot having an odd slot index. In addition, when the terminal performs repetition PUCCH transmission, if a symbol of a specific slot scheduled for PUCCH transmission overlaps with a DL symbol semi-statically configured or a symbol configured to receive an SS/PBCH block, the terminal may not transmit PUCCH on a slot including the overlapping symbol. The terminal may delay transmission of the non-transmitted PUCCH in order to transmit the non-transmitted PUCCH on a subsequent slot. In this case, if the symbol of the slot for the delayed PUCCH transmission does not overlap with the semi-statically configured DL symbol or the symbol configured to receive the SS/PBCH block, the terminal may transmit the PUCCH.

Examples: solution of coverage problem of uplink channel

For convenience of description, a problem related to uplink channel (e.g., PUSCH or PUCCH) repeated transmission of a UE for enhancing coverage performance is referred to as an uplink channel coverage problem.

Fig. 17 illustrates PUSCH coverage problem. Referring to fig. 17, the ue may receive a configuration of PUSCH retransmission type B for slot S and/or slot U in a TDD case. Here, the slot D is a slot in which all symbols are configured with downlink symbols, the slot U is a slot in which all symbols are configured with uplink symbols, and the slot S is a slot which is neither slot D nor slot U. The slot S may comprise at least one flexible symbol. In this case, even though the base station has indicated to the UE that the nominal PUSCH is 6 symbols in length, the actual PUSCH may be 2 to 4 symbols in length due to slot boundaries and invalid symbols. Each actual PUSCH may need to include at least one DMRS symbol, and if one DMRS symbol is assumed to be mapped to one actual PUSCH, the data symbol length through which uplink data can be transmitted in each actual PUSCH is thus 1 to 3 symbols. A higher coding rate needs to be used when transmitting TBs with the same number of bits compared to the existing six-symbol PUSCH transmission. Therefore, repeated transmission is configured for enhancing coverage performance, but it is difficult to obtain coding gain due to a high coding rate. Therefore, simply performing PUSCH retransmission type B may cause coverage problems. In addition, the PUSCH needs to include at least 1 DMRS symbol, and thus the smaller the number of symbols constituting the actual PUSCH, the greater the DMRS overhead. The coverage performance of the uplink channel/signal transmitted by the UE at the cell edge may be degraded. Therefore, for PUSCH retransmission type B, a solution for coverage performance enhancement is required.

Fig. 18 illustrates PUCCH coverage problem. Referring to fig. 18, the ue may receive a configuration for PUCCH repeated transmission of slot S and/or slot U in the TDD case. In case a, the UE may be configured to transmit a PUCCH having a length of a total of four symbols from 10 th to 13 th symbols, and may be configured to repeatedly transmit PUCCHs having the same position and length through two slots. In this case, the 0 th to 9 th symbols of the second slot cannot be used for PUCCH repeated transmission. Thus, if UL symbols available for PUCCH retransmission are limited, coverage problems may occur. For more reliable PUCCH transmission, limited UL symbol usage needs to be supported.

To improve coverage of the uplink channel, the UE may use the DMRS between different PUSCH repetitions or different PUCCH repetitions for joint channel estimation.

An example of PUCCH repetition reception using separate channel estimation is as follows. For example, the DMRS of the first PUCCH repetition and the DMRS of the second PUCCH repetition are transmitted in different symbols. That is, the DMRS of the first PUCCH repetition is transmitted in a first symbol among the symbols to which the first PUCCH is scheduled, and the DMRS of the second PUCCH repetition is transmitted in a second symbol among the symbols to which the second PUCCH is scheduled. The base station may perform channel estimation by using the DMRS received in the first symbol to decode the first PUCCH repetition. In addition, the base station may perform channel estimation by using the DMRS received in the second symbol to repeatedly decode the second PUCCH.

For PUCCH repetition reception using separate channel estimation, channel estimation is performed using DMRS transmitted in different symbols, respectively, and each PUCCH repetition is decoded using an estimated value. The joint channel estimation for improving the above problem is as follows.

For example, the DMRS of the first PUCCH repetition and the DMRS of the second PUCCH repetition are transmitted in different symbols. That is, the DMRS of the first PUCCH repetition is transmitted in a first symbol among the symbols to which the first PUCCH is scheduled, and the DMRS of the second PUCCH repetition is transmitted in a second symbol among the symbols to which the second PUCCH is scheduled. For joint channel estimation, DMRS transmitted in different PUCCH repetition needs to satisfy phase continuity. For example, DMRS transmitted in different PUCCH repetitions may need to satisfy at least one of (i) the same beamforming, (ii) the same quasi co-sited (QCL), and (iii) the same transmission power. If the above condition is satisfied, the base station may perform joint channel estimation by using the DMRS received in the first symbol and the DMRS received in the second symbol to decode the first PUCCH repetition and the second PUCCH repetition. In addition, the base station may receive the first PUCCH repetition and the second PUCCH repetition based on the joint channel estimation value.

Hereinafter, a method for performing joint channel estimation of PUCCH is described.

Referring to fig. 19, when the UE receives configuration/indication information of PUCCH transmission, the configuration/indication information may include at least one of the following information.

-Start symbol index: is an index of a symbol in which PUCCH transmission starts.

Number of symbols: is the number of symbols used for PUCCH transmission. In case of PUCCH format 0 or 2, the number of symbols is one of 1 and 2. In case of PUCCH formats 1, 3 or 4, the number of symbols is one of 4 to 14. For convenience of description, PUCCH format 0 or 2 is referred to as a short PUCCH, and PUCCH format 1, 3 or 4 is referred to as a long PUCCH.

-Starting PRB index: is an index of PRBs in which PUCCH transmission starts.

-Number of PRBs: is the number of PRBs used for PUCCH. The number of PRBs of PUCCH format 0, 1 or 4 is 1. In case of PUCCH format 2, the number of PRBs is one of 1 to 16. In case of PUCCH format 3, the number of PRBs is one of 1, 2,3, 4, 5, 6, 8, 9, 10, 12, 14, 15 and 16.

-Maximum code rate: is the maximum code rate at which the PUCCH format can be transmitted. The UE cannot transmit UCI exceeding the maximum code rate to the PUCCH.

In the case of PUCCH formats 2 and 3, the number of PRBs may be up to 16. The UE needs to determine one of the PRB numbers. The process is as follows. First, the UE may determine the number of bits of UCI to be transmitted via the PUCCH. Here, it is assumed that the number of bits of UCI to be transmitted via PUCCH is 0.UCI may include CRC. For PUCCH, the UE may determine the number of REs for transmitting UCI for each PRB. Here, when the number of REs for transmitting UCI is calculated, the number of REs used for DRMS may be excluded. Here, the number of REs for transmitting UCI is assumed to be N. Suppose that the modulation order used by the UE for PUCCH transmission is Q. When assuming that the PUCCH has M PRBs, the code rate is acquired according to O/(m×n×q). As described above, the maximum code rate for transmitting UCI through the PUCCH is determined as the maximum code rate. Therefore, the code rate O/(m×n×q) needs to be equal to or smaller than the maximum code rate. That is, it is necessary to satisfy O/(m×n×q). Ltoreq.maximum code rate. To meet this, the number of PRBs may be adjusted for PUCCH formats 2 and 3. That is, the UE may select a minimum PRB number satisfying O/(m×n×q). Ltoreq.max code rate among the available PRB numbers (M). To prevent the number of selected PRBs from being too small, a minimum value of the number of PRBs may be given. In this case, the UE may select the number of PRBs not smaller than the minimum value.

The UE may determine the number of PRBs (M) for PUCCH transmission according to the number of UCI bits (O), the number of REs (N) for transmitting UCI for each PRB through the PUCCH, and/or the modulation order (Q). Here, N may be given as the product of Nsc, crtl and Nsymb-UCI. Nsc, crtl is the number of REs used to transmit UCI in one symbol for each PRB. Nsymb-UCI is the number of symbols used to transmit UCI. That is, nsc, crtl is 8 in the case of PUCCH format 2, and 12 in the case of PUCCH format 3. In case of PUCCH format 2, nsymb-UCI is the same as "number of symbols". In case of PUCCH format 3, nsymb-UCI is equal to the number of symbols remaining after DMRS symbols are excluded from "the number of symbols".

Fig. 20 illustrates an example of applying joint channel coding to PUCCH repeated transmission. Referring to fig. 20, the same UCI may be repeatedly transmitted in PUCCH0 and PUCCH1 having the same symbol length. In addition, PUCCH0 and PUCCH1 may occupy the same PRB. Here, the number of PRBs in each PUCCH may be determined with reference to the above method. Each of PUCCH0 and PUCCH1 has a symbol for transmitting the DMRS. The base station may use the DMRS of PUCCH0 (12 th symbol of slot n) and the DMRS of PUCCH1 (second symbol of slot n+1) for joint channel estimation. The base station may receive UCI repeatedly transmitted in PUCCH0 and PUCCH1 by using joint channel estimation.

Fig. 19 and 20 illustrate joint channel estimation for PUCCH, but similar/identical joint channel estimation is also applied to PUSCH. An example of applying joint channel estimation to PUSCH is described in more detail below. In the disclosure, the PUSCH to which the joint channel estimation is applicable may include the following PUSCH.

The PUSCH may be a PUSCH comprising one Transport Block (TB). Here, for PUSCH, a TB Size (TBs) may be determined with reference to a plurality of slots and PUSCH may be transmitted. For example, referring to fig. 21, the ue may determine one TBS for two slots (slot n and slot n+1) for pusch#1. In this case, the DMRS symbols may be transmitted in different slots (slot n and slot n+1), but if the DMRS symbols satisfy joint channel estimation conditions through the different slots, the base station may perform joint channel estimation. In the case where the TBS is determined with reference to a plurality of slots, PUSCH repetition transmission may be applied.

The PUSCH may be a PUSCH repetition comprising 1 TB. Here, the TBS may be determined with reference to one slot, and the PUSCH may be repeatedly transmitted in a plurality of slots. For example, the UE may transmit PUSCH repetition 1 in slot n and PUSCH repetition 2 in slot n+1. In this case, the DRMS symbols may be transmitted in different slots (slot n and slot n+1), but if the DMRS symbols satisfy joint channel estimation conditions through the different slots, the base station may perform joint channel estimation. Here, the PUSCH may be a PUSCH including different TBs. Here, PUSCH may be scheduled or activated by DCI of a different strip. Alternatively, the PUSCH may be a PUSCH including a different TB and scheduled or activated by one piece of DCI. For example, referring to fig. 22, it is assumed that the UE has received an indication from the base station that pusch#1 is to be transmitted in slot n and pusch#2 is to be transmitted in slot n+1. In this case, pusch#1 and pusch#2 may be scheduled by DCIs of different bars, respectively. Pusch#1 and pusch#2 are transmitted in different slots, and thus DMRS slots are also transmitted in different slots (slot n and slot n+1), but if DMRS symbols satisfy joint channel estimation conditions in slot n/n+1, the base station may perform joint channel estimation.

In the present disclosure, joint channel estimation is described for PUCCH or PUSCH (repetition), but various methods related to joint channel estimation described in the present disclosure are not limited to PUSCH or PUCCH (repetition). That is, even in cases other than PUCCH or PUSCH (repetition) transmission, various similar or identical methods related to joint channel estimation described in the present disclosure may be applied. For example, if the DMRS of the uplink signal satisfies the joint channel estimation condition through a plurality of slots, various similar/identical methods described in the present disclosure related to the joint channel estimation may be applied to the uplink signal.

For ease of description, to summarize the joint channel estimation conditions (or joint channel estimation possible conditions) of the present disclosure, the joint channel estimation conditions may include at least one of the following conditions. For joint channel estimation of an uplink channel (e.g., PUCCH or PUSCH), the UE may need to transmit the DMRS such that joint channel estimation conditions are met.

1) The same starting PRB index: the PRB start position of the DRMS between PUCCH or PUSCH in the frequency domain needs to be the same.

2) The same number of PRBs: the number of PRBs of the DRMS between PUCCH or PUSCH in the frequency domain.

3) Phase continuity: DMRS between PUCCH or PUSCH needs to maintain phase continuity (e.g., the same phase).

4) Identical beamforming: the DMRS between PUCCH or PUSCH needs to satisfy the same beamforming.

5) The same transmit power (or power consistency): the UE needs to transmit DMRS between PUCCH or PUSCH with the same transmit power.

6) Identical quasi co-location (QCL): DMR between PUCCH or PUSCH needs to satisfy the same QCL.

Here, the starting PRB, the number of PRBs, beamforming, and QCL may be constantly maintained during uplink channel transmission based on higher layer configuration information or scheduling information received from the base station. The starting PRB may be changed in slots or between slots according to whether frequency hopping is applied. The phase of the DMRS may vary in units of slots/symbols based on slot/symbol indexes. The transmission power of the DMRS may vary in units of slots based on higher layer configuration information, power control commands, and the like. Here, the starting PRB, the number of PRBs, etc. may be included in the conditions required to maintain phase continuity and power identity/consistency. Thus, unless otherwise described, when the UE operates to meet joint channel estimation conditions, this may mean that the DMRS operates to meet 3) and 5) over multiple slots).

Further, joint channel estimation in the present disclosure may be used interchangeably with DMRS bundling.

Frequency hopping method

The problem to be solved by the present disclosure relates to a frequency hopping method when DMRS between different uplink channel repetitions transmitted by a UE is used for joint channel estimation to enhance coverage of the uplink channel. Hereinafter, for convenience of description, the present disclosure is described with respect to PUCCH, but the technical ideas of the present disclosure are also applicable to PUSCH.

First, a joint channel estimation method using DMRS between PUCCH repetition is described. Fig. 23 illustrates PUCCH repetition transmission. Referring to fig. 23, it is assumed that the UE has received an indication to repeatedly transmit PUCCH during four slots starting from slot n. In such a case, for joint channel estimation between PUCCH repetitions, the DMRS transmitted by the UE needs to satisfy at least one of, or preferably all of, the above joint channel estimation conditions.

The DMRSs of PUCCH repetition #1 to 4 of fig. 23 satisfy the same starting PRB index and number of PRBs, and thus if phase continuity, the same beamforming, the same transmission power, and the same QCL are satisfied, the DMRSs of PUCCH repetition #1 to 4 may be used for joint channel estimation. For example, the base station may perform channel estimation by jointly decoding DMRSs of PUCCH repetition #1 to 4.

The UE may be configured or may receive the indication such that the PUCCH is repeatedly transmitted through frequency hopping not only for joint channel estimation using the DMRS but also for frequency diversity gain. The following frequency hopping method may be configured or indicated by the base station for the UE.

-Intra-slot frequency hopping: the UE divides the PUCCH in half in the time domain within the slot indicating PUCCH transmission and maps it to two hops. Here, the PUCCH may or may not be repeatedly transmitted. When the length/number of symbols of the allocated PUCCH in one slot is N ^PUCCH,s _symb, floor (N ^PUCCH,s _symb/2) symbols may be mapped to the first hop and N ^PUCCH,s _symb-floor(N^PUCCH,s _symb/2) symbols may be mapped to the second hop. Referring to fig. 24, it is assumed that the UE has received an indication that PUCCH is to be repeatedly transmitted for four slots starting from slot n and intra-slot frequency hopping is to be performed. At this time, the length N ^PUCCH,s _symb of the symbol to which the PUCCH is allocated in one slot is 14. The UE may map a first floor (N ^PUCCH,s _symb/2) =7 symbols of the PUCCH to the first transition and map the next N ^PUCCH,s _symb-floor(N^PUCCH ^,s _symb/2) =7 symbols of the PUCCH to the second transition in slots N, n+1, n+2, and n+3. The first hop may be transmitted in a first frequency band and the second hop may be transmitted in a second frequency band. As many as N _PRB PRBs from the starting PRB index are configured as first hopped PRBs, and as many as N _PRB PRBs from the second hopped PRB index are configured as second hopped PRBs.

In a similar scheme, in case of PUSCH retransmission, the UE may divide PUSCH in two halves in the time domain in a slot indicating PUSCH retransmission and map it to two hops. Here, PUSCH may or may not be repeatedly transmitted. When the length/number of symbols to which PUSCH is allocated in one slot is N ^PUCCH,s _symb, floor (N ^PUCCH,s _symb/2) symbols may be mapped to the first hop and N ^PUCCH,s _symb-floor(N^PUCCH,s _symb/2) symbols may be mapped to the second hop. As many PRBs as the number of scheduled PRBs starting from RB _start may be configured as the first hopped PRBs and as many PRBs as the number of scheduled PRBs starting from { (RB _start+RB_offset)mod N^size _BWP } may be configured as the second hopped PRBs here, RB _start indicates the starting PRB index within UL BWP, RB _offset indicates the hopping offset value configured by the base station, and N ^size _BWP indicates the number of PRBs constituting UL BWP.

Inter-slot frequency hopping: the repeated transmission slot index may be sequentially numbered with reference to the first slot of the PUCCH repeated transmission. Here, the repetition transmission slot index of the first slot of the PUCCH repetition transmission may be 0. Referring to fig. 25, it is assumed that the UE has received an indication of PUCCH repetition transmission and inter-slot frequency hopping of four slots starting from slot n. In this case, the retransmission slot index of slot n of the first slot of the PUCCH retransmission may be 0. In addition, the retransmission slot indexes of slots n to n+3 may be 0,1, 2, and 3 in order. In this case, for example, the UE may map the PUCCH to a first transition in a slot corresponding to an even-numbered repetition transmission slot index and may map the PUCCH to a second transition in a slot corresponding to an odd-numbered repetition transmission slot index. Here, as many PRBs as the number of PRBs starting from the starting PRB may be configured as the first hopped PRB, and as many PRBs as the number of PRBs starting from the second hopped PRB index may be configured as the second hopped PRB. That is, the UE may transmit PUCCH in the first transition in slot n and slot n+2, and transmit PUCCH in the second transition in slot n+1 and slot n+3.

In a similar scheme, in case of PUSCH retransmission, the UE may map PUSCH to the first hop or the second hop with reference to an absolute slot index in a radio frame including a slot of PUSCH retransmission. For example, if the index in the radio frame including the slot of the PUSCH retransmission is even, the corresponding PUSCH retransmission may be mapped to the first hop. In addition, if an index in a radio frame including a slot of PUSCH retransmission is an odd number, the corresponding PUSCH retransmission may be mapped to the second hop. As many PRBs as the number of PRBs scheduled from RB _start may be configured as the first hopped PRB and as many PRBs as the number of PRBs scheduled from { (RB _start+RB_offset)mod N^size _BWP } may be configured as the second hopped PRB-here, RB _start indicates the starting PRB index within UL BWP, RB _offset indicates the hopping offset value configured by the base station, and N ^size _BWP indicates the number of PRBs constituting UL BWP.

During PUCCH repeated transmission by frequency hopping, the DMRS of the first hop and the DMRS of the second hop are transmitted in different PRBs, and thus joint channel estimation between PUCCH repeated transmissions is not possible. In the present disclosure, various frequency hopping methods for frequency diversity gain according to frequency hopping and coverage enhancement by joint channel estimation using DMRS are described.

In the following example, the UE may transmit a first hop in the frequency domain in a first PRB and a second hop in the frequency domain in a second PRB. The UE may determine the "number of PRBs" PRBs starting from the PRB corresponding to the starting PRB index as a first PRB and the "number of PRBs" PRBs starting from the PRB corresponding to the second hopping PRB index as a second PRB. Alternatively, the UE may determine as many PRBs as the number of scheduled PRBs starting from RB _start as a first PRB and as many PRBs as the number of scheduled PRBs starting from { (RB _start+RB_offset)mod N^size _BWP } as a second PRB, where RB _start indicates a starting PRB index within UL BWP, RB _offset indicates a hopping offset value configured by the base station, and N ^size _BWP indicates the number of PRBs constituting UL BWP.

In the following example, inter-slot hopping is assumed. For example, the UE may map PUCCH repeated transmissions to a first (or second) transition in an even-numbered repeated transmission slot index and PUCCH repeated transmissions to a second (or first) transition in an odd-numbered repeated transmission index.

According to a first example of the present disclosure, a UE may maintain the same PUCCH retransmission slot index for a certain number (hereinafter, M) of slots. In addition, the UE may sequentially increase PUCCH retransmission slot index every certain number of slots. Here, the specific number may be the number of PUCCH repetition for jointly decoding the DMRS symbols for joint channel estimation. Suppose that the UE has received an indication that PUCCH is to be repeatedly transmitted in N slots, and a specific number is M. In such a case, the retransmission slot index for M (consecutive) slots of the first slot of the repetition transmission of the PUCCH indicated by the reference is determined to be 0. The retransmission slot index may be sequentially increased every M consecutive slots. Here, the retransmission slot index may be determined regardless of whether there is PUCCH retransmission. Thereafter, the UE may map the PUCCH to a first transition in a slot corresponding to the even-numbered retransmission slot index. In addition, the UE may map the PUCCH to a second transition in a slot corresponding to the odd-numbered retransmission slot index. Here, as many PRBs as the "number of PRBs" starting from the starting PRB index are configured as first hopped PRBs, and as many PRBs as the "number of PRBs" starting from the second hopped PRB index are configured as second hopped PRBs.

For example, referring to fig. 26, assume that the UE has received an indication that configurations n=4 and m=2 and will repeatedly transmit PUCCH from slot N. The UE may determine the repeat transmission slot index of m=2 slots (i.e., slot n and slot n+1) starting from slot n as 0, and may determine the repeat transmission slot index of two slots (i.e., slot n+2 and slot n+3) starting from slot n+2 as 1. The repeated transmission slot index of slot n and slot n+1 is 0, and thus the PUCCH of the slot may be transmitted in the first transition, and the repeated transmission slot index of slot n+2 and slot n+3 is 1, and thus the PUCCH of the slot may be transmitted in the second transition.

For example, referring to fig. 27, assume that the UE has received an indication that configurations n=4 and m=2 and PUCCH is to be repeatedly transmitted from slot N. Here, the slot n+1 is assumed to be a slot in which PUCCH transmission is impossible, and the slots n, n+2, n+3, and n+4 are assumed to be slots in which PUCCH transmission is possible. The UE may allocate the retransmission slot index in units of two slots starting from the slot n. That is, the UE may determine that the repeat transmission slot index of the slot n/n+1 is 0, the repeat transmission slot index of the slot n+2/n+3 is 1, and the repeat transmission slot index of the slot n+4/n+5 is 2. The repeat transmission slot index of slot n/n+1 is 0, so that the PUCCH of the slot may be transmitted at the first transition, the repeat transmission slot index of slot n+2/n+3 is 1, so that the PUCCH of the slot may be transmitted at the second transition, and the repeat transmission slot index of slot n+4/n+5 is 2, and so that the PUCCH of the slot may be transmitted at the first transition. The UE needs to transmit PUCCH in n=4 slots, and thus transmits PUCCH in four slots, i.e., slot N, slot n+2, slot n+3, and slot n+4, in consideration of whether PUCCH transmission is possible. Accordingly, PUCCHs of slots n and n+4 may be transmitted in the first transition, and PUCCHs of slots n+2 and n+3 may be transmitted in the second transition.

In the case of applying the first example to PUSCH, the retransmission slot index may be determined with reference to the absolute slot index in the radio frame. For example, according to a first example, assume that the UE has received an indication to repeatedly transmit PUSCH in N slots, and a specific number is M. In this case, the UE may determine a retransmission slot index from a first slot in which PUSCH retransmission is indicated according to floor (n ^μ _s/M). Here, n ^μ _s is an absolute slot index in a radio frame including a slot of PUSCH repetition transmission with a subcarrier spacing μ. The retransmission slot index floor (n ^μ _s/M) may be sequentially increased every M consecutive slots. Here, the retransmission slot index may be determined regardless of whether there is PUSCH retransmission. Hereinafter, when the repetition transmission slot index floor (n ^μ _s/M) including the slots of PUSCH repetition transmission is even, the UE may map it to the first hop, and when the repetition transmission slot index floor (n ^μ _s/M) is even, the UE may map it to the first hop, and when the repetition transmission slot index floor (n ^μ _s/M) including the slots of PUSCH repetition transmission is odd, the UE may map it to the second hop. As many PRBs as the number of scheduled PRBs starting from RB _start may be configured as the first hopped PRBs and as many PRBs as the number of scheduled PRBs starting from { (RB _start+RB_offset)mod N^size _BWP } may be configured as the second hopped PRBs here, RB _start indicates the starting PRB index within UL BWP, RB _offset indicates the hopping offset value configured by the base station, and N ^size _BWP indicates the number of PRBs constituting UL BWP.

In the first example above, the first UE maintains the same repetition slot index in M consecutive slots, regardless of whether the PUCCH is transmitted or not. In addition, PUCCHs transmitted in M consecutive slots are transmitted in the same frequency band. The PUCCH cannot be transmitted in some of the M consecutive slots, and thus the number of slots in which the PUCCH is transmitted among the M consecutive slots may be equal to or less than M. An example of solving this problem is as follows.

According to a second example of the present disclosure, the UE may maintain the same PUCCH retransmission slot index for a specific number of slots in which PUCCH retransmission is possible. In addition, the UE may sequentially increase each specific number of slots in which PUCCH retransmission is possible. Here, the specific number may be the number of PUCCH repetition for jointly decoding the DMRS symbols for joint channel estimation. It is assumed that the UE has received an indication that PUCCH is to be repeatedly transmitted in N slots, and the specific number is M. At this time, the first PUCCH repeated transmission for the PUCCH repeated transmission indicated by the repeated transmission slot index reference for M slots capable of transmitting PUCCH is determined to be 0. The retransmission slot index may be sequentially increased in every M slots in which PUCCH transmission is possible.

For example, referring to fig. 28, assume that the UE has received an indication that configurations n=4 and m=2 and that PUCCH is to be repeatedly transmitted from slot N. Here, the slot n+1 is assumed to be a slot in which PUCCH transmission is impossible, and the slots n, n+2, n+3, and n+4 are assumed to be slots in which PUCCH transmission is possible. The UE may determine the retransmission slot index of m=2 slots (i.e., slot n and slot n+2) where PUCCH retransmission is possible starting from slot n as 0, and may determine the retransmission slot index of slot n+3 and slot n+4 as 1. Thus, PUCCHs of slots n and n+2 may be transmitted in a first transition, and PUCCHs of slots n+3 and n+4 may be transmitted in a second transition.

In the case of applying the second example to PUSCH, the retransmission slot index may be determined with reference to the relative slot index in a radio frame in which PUSCH retransmission is possible. That is, according to the second example, it is assumed that the UE has received an instruction to repeatedly transmit PUSCH in N slots, and the specific number is M. In this case, the UE may determine a retransmission slot index from a first slot in which PUSCH retransmission is indicated, in which PUSCH transmission is possible, according to floor (n ^μ _s/M). Here, n ^μ _s is a relative slot index in a radio frame of slots with subcarrier spacing μ, where PUSCH repetition transmission is possible. The repeated transmission slot index floor (n ^μ _s/M) may be sequentially increased every M slots, where PUSCH transmission is possible. Thereafter, when a retransmission slot index including a slot of PUSCH retransmission is even, the UE may map the corresponding PUSCH to the first hop. In addition, when the retransmission slot index including the slots of the PUSCH retransmission is an odd number, the UE may map the corresponding PUSCH to the second hop. As many PRBs as the number of scheduled PRBs starting from RB _start may be configured as the first hopped PRBs and as many PRBs as the number of scheduled PRBs starting from { (RB _start+RB_offset)mod N^size _BWP } may be configured as the second hopped PRBs, where RB _start indicates the starting PRB index within UL BWP, RB _offset indicates the hopping offset value configured by the base station, and N ^size _BWP indicates the number of PRBs constituting UL BWP.

Referring to fig. 28, it is assumed that a slot n+1 is a slot in which PUSCH transmission is impossible, and a slot n (n ^μ _s =0), a slot n+2 (n ^μ _s =1), a slot n+3 (n ^μ _s =2), and a slot n+4 (n ^μ _s =3) are slots in which PUSCH transmission is possible. The UE may determine a retransmission slot in which PUSCH retransmission is possible m=2 slots (i.e., slot n and slot n+2) as 0 and a retransmission slot index of slot n+3 and slot n+4 as 1. Accordingly, PUSCHs of slots n and n+2 may be transmitted in the first transition, and PUSCHs of slots n+3 and n+4 may be transmitted in the second transition.

With the first and second examples above, the UE may determine a slot in which to transmit the PUCCH in the first (or second) transition and a slot in which to transmit the PUCCH in the second (or first) transition. In view of joint channel estimation, it is preferable to transmit PUCCH in the same PRB in consecutive slots.

For example, referring to fig. 26, pucch is transmitted in the first transition in two consecutive slots (slot n and slot n+1), and thus DMRS joint channel estimation using slot n and slot n+1 is possible. In addition, the PUCCH is transmitted in the second transition in two consecutive slots (slot n+2 and slot n+3), and thus DMRS joint channel estimation using slots n+2 and slot n+3 is possible.

For example, referring to fig. 27, pucch is transmitted in the second transition in two consecutive slots (slot n+2 and slot n+3), and thus DMRS joint channel estimation using slots n+2 and slot n+3 is possible. However, PUCCH is transmitted in the same hop in slot n and slot n+4, but joint channel estimation using DMRS of slot n and slot n+4 is not possible due to the time interval (i.e., non-contiguous) between the two slots.

For example, referring to fig. 28, PUCCH is transmitted in the second transition in two consecutive slots (slot n+3 and slot n+4), and thus joint channel estimation of DMRS using PUCCHs of slot n+3 and slot n+4 is possible. However, PUCCH is transmitted in the same hop in slot n and slot n+2, but joint channel estimation using DMRS of slot n and slot n+2 is not possible due to the time interval (i.e., non-contiguous) between the two slots.

Therefore, it is preferable for the UE to transmit PUCCH in the same hop in the consecutive slots available.

More specifically, the first example and the second example are described with reference to fig. 29 and 30.

In fig. 29, it is assumed that the UE has received the indications that configurations n=4 and m=2 and will repeatedly transmit PUCCH from slot N. Here, it is assumed that slot n+1, slot n+2, and slot n+5 are slots in which PUCCH transmission is impossible, and slot n, slot n+3, slot n+4, and slot n+6 are slots in which PUCCH transmission is possible. The UE needs to transmit PUCCH in n=4 slots, and thus may transmit PUCCH in slot N, slot n+3, slot n+4, and slot n+6.

Referring to fig. 29a, the ue may determine a transition in a slot in which to transmit a PUCCH according to a first example. Specifically, m=2 slots are grouped, and the same retransmission slot index can be determined regardless of whether the PUCCH is transmitted. In addition, the retransmission slot index may sequentially increase every m=2 slots. Here, the repeat transmission slot index of the slot n corresponding to the first slot of the PUCCH repeat transmission is 0. Therefore, the repeat transmission slot index of the slot n and the slot n+1 is 0, the repeat transmission slot index of the slot n+2 and the slot n+3 is 1, the repeat transmission slot index of the slot n+4 and the slot n+5 is 2, and the repeat transmission slot index of the slot n+6 is 3. The UE may transmit the PUCCH in the first transition in slot n and slot n+4 whose repeated transmission slot index is even. In addition, the UE may transmit the PUCCH in the second transition in the slots n+3 and n+6 whose repeated transmission slot indexes are odd.

Referring to fig. 29b, the ue may determine a transition in a slot in which a PUCCH is to be transmitted according to a second example. Specifically, m=2 slots in which PUCCH transmission can be performed are grouped, and the same repeated transmission slot index can be determined. In addition, the repetition transmission slot index may be sequentially increased in every m=2 slots in which PUCCH transmission is possible. Here, the repeat transmission slot index of the slot n corresponding to the first slot of the PUCCH repeat transmission is 0. Therefore, the repeat transmission slot index of the slot n and the slot n+3 is 0, and the repeat transmission slot index of the slot n+4 and the slot n+6 is 1. The UE may transmit the PUCCH in the first transition in slot n and slot n+3 whose repeated transmission slot index is even. In addition, the UE may transmit the PUCCH in the second transition in the slots n+4 and n+6 whose repeated transmission slot indexes are odd.

In fig. 29, according to the first and second examples, it may be identified that PUCCH is transmitted in different hops in slot n+3 and slot n+4. Referring to fig. 29a, according to a first example, the UE may transmit PUCCH in the second transition in slot n+3 and PUCCH in the first transition in slot n+4. Referring to fig. 29b, according to a second example, the UE may transmit the PUCCH in a first transition in slot n+3 and may transmit the PUCCH in a second transition in slot n+4.

In fig. 30, it is assumed that the UE has received the indications that configurations n=8 and m=2 and will repeatedly transmit PUCCH from slot N. Here, the slots n+3, n+4, and n+7 are assumed as slots in which PUCCH transmission is impossible, and the slots n, n+1, n+2, n+5, n+6, n+8, n+9, and n+10 are assumed as slots in which PUCCH transmission is possible. The UE needs to transmit PUCCH in n=8 slots, and thus may transmit PUCCH in slot N, slot n+1, slot n+2, slot n+5, slot n+6, slot n+8, slot n+9, and slot n+10.

Referring to fig. 30a, the ue may determine a transition in a slot in which to transmit a PUCCH according to the first example. Specifically, m=2 slots are grouped, and the same retransmission slot index can be determined regardless of whether the PUCCH is transmitted. In addition, the retransmission slot index may sequentially increase every m=2 slots. Here, the repeat transmission slot index of the slot n corresponding to the first slot of the PUCCH repeat transmission is 0. Therefore, the repeat transmission slot index of the slot n and the slot n+1 is 0, the repeat transmission slot index of the slot n+2 and the slot n+3 is 1, the repeat transmission slot index of the slot n+4 and the slot n+5 is 2, the repeat transmission slot index of the slot n+6 and the slot n+7 is 3, the repeat transmission slot index of the slot n+8 and the slot n+9 is 4, and the repeat transmission slot index of the slot n+10 is 5. The UE may transmit the PUCCH in the first transition in the slot n, slot n+1, slot n+5, slot n+8, and slot n+9, whose repeated transmission slot index is even. In addition, the UE may transmit the PUCCH in the second transition in the slots n+2, n+6, and n+10 whose repeated transmission slot indexes are odd.

Referring to fig. 30b, the ue may determine a transition in a slot in which a PUCCH is to be transmitted according to a second example. Specifically, m=2 slots in which PUCCH transmission is possible are grouped, and the same repeated transmission slot index may be determined. In addition, the repetition transmission slot index may be sequentially increased in every m=2 slots in which PUCCH transmission is possible. Here, the repeat transmission slot index of the slot n corresponding to the first slot of the PUCCH repeat transmission is 0. Therefore, the repeat transmission slot index of the slot n and the slot n+1 is 0, the repeat transmission slot index of the slot n+2 and the slot n+5 is 1, the repeat transmission slot index of the slot n+6 and the slot n+8 is 2, and the repeat transmission slot index of the slot n+9 and the slot n+10 is 3. The UE may transmit PUCCH in the first transition of slots n, n+1, n+6, n+8 whose repeated transmission slot index is even. In addition, the UE may transmit the PUCCH in the second transition in the slots n+2, n+5, n+9, and n+10 in which the repetition transmission slot index is odd.

In fig. 30, according to the first and second examples, it may be identified that PUCCH is transmitted in different hops in slot n+5 and slot n+6. Referring to fig. 30a, according to a first example, a UE may transmit a PUCCH in a first transition in slot n+5 and transmit a PUCCH in a second transition in slot n+6. Referring to fig. 30b, according to a second example, the UE may transmit the PUCCH in the second transition in slot n+5 and may transmit the PUCCH in the first transition in slot n+6. As described above, for joint channel estimation, PUCCH needs to be transmitted in the same hop in consecutive slots. However, as shown in fig. 29 and 30, when PUCCH is transmitted even though there are consecutive slots in different hops, joint channel estimation cannot be performed. An example of solving this problem is as follows.

According to a third example of the present disclosure, the UE may determine the same PUCCH retransmission slot index only for a slot among a specific number of slots in which PUCCH retransmission is possible. Here, the slots in which joint channel estimation is possible may be consecutive slots in the time domain in which PUCCH repeated transmission is possible. The particular number may be a number of PUCCH repetitions for jointly decoding DMRS symbols for joint channel estimation.

When it is assumed that the UE has received an indication that PUCCH is to be repeatedly transmitted in N slots and the specific number is M, more specifically, a third example is as follows. The UE may group M consecutive slots among slots in which PUCCH transmission is possible and determine the same retransmission slot index for the same. In addition, for consecutive slots among slots in which PUCCH transmission is possible, the repetition transmission slot index may be sequentially increased every M slots. If the number of consecutive slots among slots in which PUCCH transmission is possible is less than M, the UE may determine the same retransmission slot index for consecutive slots whose number is less than M. Different retransmission indexes may be determined for non-consecutive time slots. The retransmission slot index may be assigned in ascending order from the front-most slot to the rear-most slot among the non-consecutive slots.

A third example may be indicated as follows. Consecutive slots starting from the first slot of the PUCCH repeated transmission may be acquired from among slots in which PUCCH transmission is possible. Consecutive slots may be grouped every M slots and the retransmission slot index may be sequentially increased. Here, the repetition transmission slot index of the first slot of the PUCCH repetition transmission is 0. That is, if there are M consecutive slots starting from the next slot where PUCCH transmission is possible, the repeated transmission slot index of the slot is 1. This process may be performed for consecutive time slots. If a discontinuous slot is found, the UE may find a continuous slot after the discontinuous slot. If the repeat transmission slot index of the slot preceding the discontinuous slot is X, the repeat transmission index of the first slot among the continuous slots following the discontinuous slot may be x+1. Consecutive slots following the non-consecutive slots may be grouped every M slots, and the retransmission slot index may be sequentially increased. That is, the retransmission slot index of M slots including the first slot among consecutive slots after the non-consecutive slot is x+1.

Referring to fig. 31a, the ue may determine a transition to transmit the PUCCH according to a third example. Specifically, consecutive m=2 slots in which PUCCH transmission is possible may be grouped, and the same repetition slot index may be determined. For example, the UE may find a slot in which PUCCH transmission is possible and consecutive to slot n. There is no slot in which PUCCH transmission is possible and consecutive to slot n, and the repeat transmission slot index of slot n may be 0. Slots n+1 and n+2 are slots where PUCCH transmission is not possible. The repeat transmission slot index for slot n+3 may be 1. The UE may find slot n+3 and slot n+4 as consecutive slots starting from slot n+3, where PUCCH transmission is possible. The UE may assign the same retransmission slot index to slot n+3 and slot n+4 corresponding to m=2 consecutive slots starting from slot n+3, where PUCCH transmission is possible. Slot n+5 is a slot where PUCCH transmission is not possible. The repeat transmission slot index of slot n+6, where PUCCH transmission is possible, may be 2. Thus, the PUCCH is transmitted in a first transition in the slots n and n+6 whose repeated transmission slot indexes are even, and the PUCCH is transmitted in a second transition in the slots n+3 and n+4 whose repeated transmission slot indexes are odd. In comparison with fig. 29 and 30, the PUCCH is transmitted in the same hop in the slot n+3 and the slot n+4, and thus the base station can perform joint channel estimation by using the PUCCH DMRS of the slot n+3 and the slot n+4.

Referring to fig. 31b, the ue may determine a transition in a slot in which the PUCCH is to be transmitted according to a third example. Specifically, m=2 consecutive slots in which PUCCH transmission is possible are grouped, and the same repeated transmission slot index may be determined. For example, the UE may find slot n+1 as a slot in which PUCCH transmission is possible and consecutive to slot n. Thus, the UE may assign 0 to the slot n and the slot n+1 corresponding to m=2 consecutive slots starting from the slot n in which PUCCH transmission is possible, corresponding to the same repeated transmission slot index as the slot n. The repeat transmission slot index for slot n+2 may be 1. There are no slots in which PUCCH transmission is possible and contiguous with slot n+2. Slots n+3 and n+4 are slots in which PUCCH transmission is not possible. The repeat transmission slot index for slot n +5 may be 2. The UE may find slot n+5 and slot n+6 as consecutive slots starting from slot n+5 where PUCCH is possible. The UE may assign a slot n+5 and a slot n+6 corresponding to m=2 consecutive slots starting from the slot n+5, in which PUCCH transmission is possible, to a repeat transmission slot index corresponding to the same as the slot n+5.

According to a fourth example of the present disclosure, a UE may receive a configuration or indication of a period and an offset of a time window for frequency hopping. The UE may apply a period and an offset to a slot in which PUCCH retransmission is indicated, and map the repeated transmission in the period to the same hop and perform transmission.

According to an example, the UE may receive a configuration or indication of the same period and offset regardless of the number of PUCCH repeated transmissions configured or indicated. For example, referring to fig. 32, when the UE has received a configuration or indication of the PUCCH retransmission number n=4 or 8 in a cell in which the subcarrier spacing is 15kHz, the UE may apply a period of 2ms and an offset of 0ms in all cases. Thus, in case of n=4 or 8, the UE may map two PUCCH repeated transmissions to one hop and perform transmission.

According to another example, the UE may receive configurations or indications of different periods and offsets according to the number of configured or indicated PUCCH repeated transmissions. For example, referring to fig. 33, when the UE is in a cell with a subcarrier spacing of 15kHz, it may be configured or indicated as a 2ms period and 0ms offset for n=4 and as a 4ms period and 0ms offset for n=8. Thus, the UE may map two PUCCH repeated transmissions to one hop in the case of n=4, and may map four PUCCH repeated transmissions to one hop and perform transmission in the case of n=8.

Method for determining the number (N) or a specific number (M) of retransmission slots

In the above examples, the UE may receive a configuration or explicit or implicit indication of the number (N) of repeated transmission slots and/or a specific number (M) of uplink channels (e.g., PUCCH or PUSCH) from the base station. In the following, a method for a UE to determine the number and/or a specific number of retransmission slots is described in the present disclosure.

According to a first example, the UE may repeatedly map PUCCH to the same frequency hopping and transmit for a preconfigured number of slots. In this case, the UE may receive a configuration or indication of the same value M regardless of the number (N) of PUCCH repeated transmissions. The UE may map M slots of a time preceding slot among slots indicating PUCCH transmission to a first transition, and map the next M slots to a second transition and perform transmission. Thus, joint channel estimation is possible for every M PUCCH repeated transmissions. For example, referring to fig. 34, when the UE has received a configuration or indication of the PUCCH repetition transmission number n=2, 4, or 8, the UE may apply m=2 to all cases and perform transmission by mapping two slots to one hop. However, in the case of n=2, two slots are mapped to the same hopping, which results in the same result as the case where frequency hopping is not performed, and thus frequency diversity gain cannot be acquired.

According to a second example, the UE may repeatedly map PUCCH to the same frequency hopping and perform transmission for a preconfigured number of slots. In this case, the UE may receive a configuration or indication of a preconfigured number of slots having different M values according to the number of PUCCH repeated transmissions. For example, the UE may receive a configuration or indication of an M value having a function of the number N of PUCCH repeated transmissions (e.g., M (N)). Thus, the UE may perform flexible frequency hopping according to the number of PUCCH repeated transmissions. For example, referring to fig. 35, when configuring/indicating [ n=2, m (2) =1 ], [ n=4, m (4) =2 ], or [ n=8, m (8) =2 ], the UE may map 1 slot to one hop with n=2; mapping 2 slots to one hop in the case of n=4; and maps 4 slots to one hop with n=8.

In the first and second examples, the UE may always apply the same M value without additional configuration from the base station.

In the first and second examples, the method for mapping a predetermined number of PUCCH repetition or slots for joint channel estimation to one hop from a point of time at which PUCCH repetition transmission is indicated and performing transmission has been described. Hereinafter, a method for performing frequency hopping on PUCCH repetition and transmitting the repetition by a UE without receiving configuration and indication of the number of PUCCH repetition or slots to be mapped to one hop is described.

According to a third example, the UE may perform frequency hopping for PUCCH repetition based on the number of frequency hopping, and perform transmission. The UE may determine PUCCH repeated transmission to be mapped to each hop according to the number of hops to be mapped to transmit a total of N PUCCH repeated transmissions. Here, the number of frequency hopping refers to the number of PUCCH repetition in the time domain, which satisfies a condition that joint channel estimation is possible. That is, referring to fig. 32, in the case where n=8, there are four total hopping frequencies including hopping frequency #1 (repetition #1 and repetition # 2), hopping frequency #2 (repetition #3 and repetition # 4), hopping frequency #3 (repetition #5 and repetition # 6), and hopping frequency #4 (repetition #7 and repetition # 8).

According to the (3-1) th example, the UE may perform frequency hopping of PUCCH repetition based on the number of frequency hopping configured or indicated from the base station and perform transmission. The UE may receive a configuration or indication to perform mapping for a total of N PUCCH repeated transmissions using K hops. For example, the UE may repeatedly map floor (N/K) PUCCHs to the first to (K-1) th hops in ascending order, and ceil (N/K) PUCCHs to the kth hops in ascending order. For example, referring to fig. 36, when the UE has received an indication of the total PUCCH repetition transmission number n=8 and the frequency hopping number k=4, the UE may perform transmission by mapping floor (8/4) =2 PUCCH repetition to frequency hopping #1, #2, and #3, and mapping ceil (8/4) =2 PUCCH repetition transmission to frequency hopping #4. That is, the UE may perform transmission by mapping PUCCH repeated transmission as follows: frequency hopping # 1= (repetition #1 and repetition # 2); frequency hopping # 2= (repetition #3 and repetition # 4); frequency hopping # 3= (repetition #5 and repetition # 6); and frequency hopping # 4= (repetition #7 and repetition # 8). In another example, the UE may perform transmission by repeatedly mapping ceil (N/K) PUCCHs to the first hop in ascending order and floor (N/K) PUCCHs to the second to kth hops in ascending order.

According to the (3-2) th example, the UE may transmit PUCCH repetition by performing frequency hopping on PUCCH repetition based on the same number of frequency hopping at all times without an instruction from the base station. This is a method for distributing the maximum number of PUCCH repetition to equal frequency hopping when the UE is configured to perform PUCCH repetition transmission and apply both frequency hopping and joint channel estimation. For example, the UE may always divide a total of N PUCCHs repeatedly into two hops and perform transmission. Similar to the method of dividing PUCCH symbols in one slot into two equal hops in intra-slot hopping, the UE may perform transmission by repeatedly mapping floor (N/2) PUCCHs to a first hop in ascending order and N-floor (N/2) PUCCHs to a second hop in ascending order. For example, referring to fig. 37, when the UE has received an indication of the total PUCCH repetition transmission number n=8, the UE may perform transmission by mapping floor (8/2) =4 PUCCH repetitions to frequency hopping #1 and ceil (8/2) =4 PUCCH repetitions to frequency hopping # 2. That is, the UE may perform transmission that may map PUCCH repeated transmission as follows: jump # 1= (repetition #1, repetition #2, repetition #3, and repetition # 4); and hop # 2= (repetition #5, repetition #6, repetition #7, and repetition # 8). In another example, when transmission is performed by always dividing a total of N PUCCH repetitions into two hops, the UE may perform transmission by mapping ceil (N/2) PUCCH repetitions to a first hop and floor (N/2) PUCCH repetitions to a second hop.

Time window interval configuration for joint compilation

Next, for joint channel estimation, the UE may be configured or instructed to meet joint channel estimation conditions in a particular time window or Time Domain Window (TDW) (or bundling window). Here, the above (1) PUCCH or PUSCH repetition, (2) PUCCH or PUSCH including one TB, and (3) PUCCH or PUSCH including a different TB may be included in the TDW. The UE may determine a TDW to be applied to PUCCH or PUSCH transmission by using the following method based on explicit/implicit information received from the base station.

As a first method, the UE may receive explicit information of the length of the TDW from the base station. Explicit information may be received through higher layer signals (e.g., RRC signals). The length of the TDW may include the number of slots, the number of symbols, or the number of repetitions. Here, the number of repetitions includes the number of PUCCH repetitions or the number of PUSCH repetitions. When the UE receives information about the length of the TDW from the base station, the UE may transmit the DMRS for the PUCCH or PUSCH such that joint channel estimation conditions in the TDW having the corresponding length are satisfied. For example, the UE may maintain phase continuity and power consistency of the DMRS through multiple slots/repetitions in the TDW.

When the UE has received the information about the length of the TDW, a point of time of the length of the TDW will be applied. This may be determined by one of the following methods.

The length of the TDW may be applied starting from the first symbol of the first slot of radio frame index 0. For example, when the TDW length is given as five slots, five slots starting from the first slot of the radio frame index 0 may be grouped and determined as TDW. Here, the index of the first slot of the radio frame index 0 is 0.

The TDW length may be applied starting from the first uplink symbol of the first uplink slot of radio frame index 0. Here, the uplink slot indicates a slot including only uplink symbols. For example, when the TDW length is given as five slots, five slots starting from the first uplink slot of radio frame index 0 may be grouped and determined as TDW.

The TDW length may be applied starting from the first non-downlink symbol of the first non-downlink slot of radio frame index 0. Here, the non-downlink slot indicates a slot including at least one non-downlink symbol, and the non-downlink symbol indicates a symbol other than a downlink symbol. In particular, if the type of symbol is a downlink symbol, an uplink symbol, or a flexible symbol, the non-downlink symbol indicates an uplink symbol or a flexible symbol. For example, if the TDW length is given as five slots, five slots starting from the first non-downlink slot of radio frame index 0 may be grouped and determined as TDW.

The UE may receive a configuration of offset values for the starting point of the TDW length. Here, the offset value may be given as the number of slots, the number of symbols, or the number of repetitions. For example, if an offset value of X slots/symbols/repetitions is given as a starting point of the TDW length, the UE may group as many slots/symbols/repetitions as the TDW length after X slots/symbols/repetitions starting from the starting point, so that the TDW is determined. Here, the offset value X is shorter than the length of the TDW. Here, the starting point may be determined according to the above example.

In case of PUSCH repetition or PUCCH repetition transmission, the TDW length may be determined according to a slot from which the corresponding repetition transmission starts. Here, PUSCH repetition transmission may include: PUSCH repetition transmission type a or PUSCH repetition transmission type B including the same TB. The PUCCH repeated transmission may include the same UCI, and may include PUCCH repeated transmission transmitted in the same PUCCH format.

In case of PUSCH including one TB and having a TBs determined with reference to a plurality of slots, the TDW length may be applied starting from the first slot where the corresponding PUSCH transmission starts.

-If PUSCH including one TB and having a TBs determined with reference to a plurality of slots is repeatedly transmitted, the TDW length can be applied starting from the first slot where the repeated transmission of the corresponding PUSCH starts.

As another example of the first method, the UE may receive a configuration of one or more TDW lengths. Referring to fig. 38, when the UE receives the TDD configuration, two patterns may be configured for the UE. Here, the two patterns have separate periods, respectively. The first pattern of periods is referred to as P and the second pattern of periods is referred to as P2. For reference, p+p2 needs to be one of the divisors of 20 ms. Each of the patterns may include DL symbols, UL symbols, and flexible symbols. For reference, symbols may be positioned in each of patterns according to sequences of DL symbols, flexible symbols, and UL symbols. For example, referring to fig. 38, it is assumed that the UE has received the configuration of TDD configuration periods p=2 ms and p2=3 ms of the cell, and received the configuration in which the subcarrier spacing of the TDD configuration is 30 kHz. In this case, it may be difficult to satisfy both patterns using one TDW length. To this end, the UE may receive a configuration of two TDW lengths. Here, the first TDW length may include X1 slot/symbol/repetition, and the second TDW length may include X2 slot/symbol/repetition. The UE may configure X slots/symbols/repetitions starting from the point where the TDW starts as tdw#0 and may configure the next X2 slots/symbols/repetitions as tdw#1. Such TDWs with different lengths may be repeated. For reference, the value of X1 or X2 may be explicitly configured by the base station for the UE. In another example, the UE may infer TDD configuration from P and P2 without the base station explicitly configuring the UE. That is, X1 corresponds to a slot/symbol/repetition corresponding to the period P, and X2 corresponds to a slot/symbol/repetition corresponding to the period P2.

As a second method, TDW related information (e.g., TDW length) may be determined based on implicit information without receiving explicit information of the TDW. When explicit information of the TDW is not received, the UE may implicitly determine to apply the TDW in a specific interval. The implicit information may include the following items.

Number of PUCCH or PUSCH repetitions (e.g., N): when the UE has received a configuration or an indication to repeatedly transmit the PUCCH or the PUSCH, the UE may determine to transmit the PUSCH or the PUCCH by applying TDW to an interval between a time point (e.g., slot/symbol) at which the repeated transmission starts and a time point (e.g., slot/symbol) at which the repeated transmission ends. Here, the time interval in which the PUCCH or PUSCH repetition transmission is performed may be determined based on the number N of PUCCH or PUSCH repetition. Accordingly, the TDW length may be determined based on the number of slots associated with the number of PUCCH or PUSCH repetitions (e.g., the number of slots including PUCCH or PUSCH repetition transmissions). For example, referring to fig. 22 and 23, the tdw length may be determined by the length of a time interval associated with the number of uplink channel repetitions (e.g., N), e.g., including the length of a (consecutive) time interval (e.g., the number of time slots) of the uplink channel repetition. Referring to fig. 21, when a TBS is determined with reference to a plurality of slots (e.g., K), the TDW length may be determined by the length of a time interval related to an uplink transmission corresponding to k×n, for example, including the length of a time interval (e.g., the number of slots) of an uplink transmission corresponding to k×n. Here, the length of the time interval including the uplink transmission may be determined by the number of slots or the number of symbols (based on N) from the point of time when the uplink channel repeat transmission starts to the point of time when the repeat transmission ends. That is, the TDW length may be understood as the number of (consecutive) slots or symbols comprising the entire interval of the uplink channel repeat transmission. For example, referring to fig. 27, the tdw length may be determined by the number of consecutive slots from the time point (slot n) at which PUCCH repeat transmission starts to the time point (slot n+4) at which repeat transmission ends. Thus, the UE may transmit the PUCCH or PUSCH repeatedly transmitted, so that joint channel estimation is possible.

-Slot configuration: the TDW may be determined from the configuration of the time slots of the UE in the unpaired spectrum. For example, the TDW may comprise consecutive uplink time slots (including uplink channel (repeated) transmissions, e.g., where uplink channel (repeated) transmissions are performed). Here, the uplink slot is a slot including only uplink symbols. In another example, the TDW may include consecutive non-downlink time slots (including uplink channel (repeated) transmissions, e.g., where uplink channel (repeated) transmissions are performed). Here, the non-downlink slot indicates a slot including at least one non-downlink symbol, and the non-downlink symbol indicates a symbol other than a downlink symbol. More specifically, if the type of symbol is a downlink symbol, an uplink symbol, or a flexible symbol, the non-downlink symbol indicates the uplink symbol or the flexible symbol.

According to a second method, when determining the same TDW for consecutive non-downlink time slots and consecutive uplink time slots, the UE may receive a configuration from the base station such that the PDCCH is monitored or downlink signals (e.g., CSI-RS) are received in flexible symbols within the non-downlink time slots. In this case, when the PDCCH or the downlink signal is received in the corresponding symbol, it is difficult to satisfy joint channel estimation conditions (e.g., phase continuity and power consistency) between the symbol in which the PDCCH or the downlink signal is received and the symbol in which the PUSCH is transmitted. Thus, when determining a TDW for uplink joint channel estimation considering consecutive non-downlink time slots together with consecutive uplink time slots, a time slot or symbol in which a UE is configured to monitor a PDCCH or receive a downlink signal in flexible symbols of a non-downlink time slot may not be determined to have the same TDW as a previous or subsequent consecutive uplink time slot or non-downlink time slot. That is, the TDW may be configured to end (e.g., terminate existing maintenance of phase continuity and power consistency) before the UE is configured to monitor the PDCCH or receive flexible symbols of the downlink signal in a non-downlink time slot, and the TDW may be configured to start (i.e., start maintenance of new phase continuity and power consistency) after the UE is configured to monitor or receive flexible symbols of the downlink signal or PDCCH in a non-downlink time slot.

However, when a symbol in which the UE is configured to monitor the PDCCH or receive the downlink signal overlaps with a symbol in which the PUSCH is indicated to be transmitted as dynamic scheduling through the DCI format 0_0, 0_1 or 0_2, the UE may transmit the PUSCH in a corresponding slot and cancel the reception of the PDCCH or the downlink signal. In this case, even though the UE may transmit PUSCH in a previous or subsequent consecutive uplink slot and consecutive non-downlink slots in which PUSCH is transmitted to enable joint channel estimation, a non-downlink slot including a symbol in which the UE is configured to monitor PDCCH or receive downlink signals cannot be configured to have the same TDW as a previous or subsequent consecutive non-downlink slot including PUSCH transmission. The UE may not be able to perform PUSCH transmission satisfying joint channel estimation conditions. Thus, the base station may not perform joint channel estimation.

For example, referring to fig. 53, the UE may be instructed as dynamic scheduling by DCI format 0_0, 0_1 or 0_2 to transmit PUSCH in duplicate transmission type a for two slots starting from slot # 1. In this case, slot #1 and slot #2 are consecutive non-downlink and uplink slots. The UE may be configured to monitor the PDCCH in the flexible symbols of slot #1 corresponding to the non-downlink slot or to receive a downlink signal. In this case, the same TDW may not be configured for slot #1 and slot # 2. The UE cancels PDCCH or downlink signal reception and transmits PUSCH in the symbol in which the UE is configured to monitor PDCCH and receive downlink signal in slot #1, and thus joint channel estimation is possible for PUSCH transmission for slot #1 and slot # 2. However, the same TDW cannot be determined for the slot #1 and the slot #2 according to the TDW determination method (second method), and thus the UE does not need to satisfy the joint channel estimation condition when performing PUSCH repeated transmission. In addition, even if the joint channel estimation condition is satisfied and the UE transmits the DMRS when performing PUSCH repetition transmission, the base station expects to satisfy the joint channel estimation condition only within the TDW. Therefore, the base station may not perform joint channel estimation on PUSCH repeated transmissions transmitted by the UE.

To solve the above-described problems, according to an example of the present disclosure, a UE may be configured to monitor a PDCCH or receive a downlink signal in a flexible symbol, and may be configured to configure a TDW as follows according to whether a corresponding symbol overlaps with a symbol indicating PUSCH transmission as dynamic scheduling through DCI format 0_0, 0_1, or 0_2.

-When the UE is configured to monitor the PDCCH or the symbols receiving the downlink signal overlap with the symbols indicating the dynamically scheduled PUSCH transmission, no PDCCH or downlink signal is received in the respective slot or symbol. Thus, the previous or subsequent consecutive uplink time slots and consecutive non-downlink time slots may be configured to have the same TDW. Thus, phase continuity and power consistency of the DMRS may be maintained by the preceding or subsequent consecutive uplink time slots and consecutive non-downlink time slots. For example, referring to fig. 54, where the UE is configured to monitor the PDCCH or receive the symbols of the downlink signal in slot #1 overlapping with the symbols indicating the dynamically scheduled PUSCH transmission, and thus the PUSCH transmission is prioritized and the UE does not perform reception of the PDCCH or downlink signal. Thus, when the UE determines the same TDW for slot #1 and slot #2 and performs PUSCH repetition transmission, the UE may perform transmission to satisfy the condition for joint channel estimation.

-When the UE is configured to monitor that the symbols of the PDCCH or received downlink signal do not overlap with dynamically scheduled PUSCH transmission symbols, the configuration for joint channel estimation is satisfied in the respective time slots except for the symbols in which the PDCCH or downlink signal is received, and thus the UE may perform PUSCH transmission. Thus, the UE may configure the subsequent consecutive uplink time slots and consecutive non-downlink time slots to have the same TDW, except for symbols in which the PDCCH or downlink signal is received in the corresponding time slot. For example, referring to fig. 55, a PDCCH or a downlink signal may be received when a symbol in which a UE is configured to monitor the PDCCH or receive the downlink signal in slot #1 does not overlap with a symbol in which a PUSCH transmission is included. Thus, after excluding the symbol in which the PDCCH or downlink is received from the slot #1, when the UE determines the subsequent symbol and the slot #2 as TDW and performs PUSCH repetition transmission, the UE may perform transmission to satisfy the condition for joint channel estimation.

-When symbols in which the UE is configured to monitor PDCCH or receive downlink signals do not overlap with PUSCH transmission symbols dynamically scheduled in the same slot, receiving PDCCH or downlink signals in the respective slot, and thus it is difficult to satisfy the conditions for joint channel estimation. Thus, in the corresponding time slots, the previous or subsequent consecutive uplink time slots and the consecutive non-downlink time slots may not be configured to have the same TDW. For example, referring to fig. 56, even though a symbol in which a UE is configured to monitor a PDCCH or receive a downlink signal in slot #1 does not overlap with a symbol in which a dynamically scheduled PUSCH transmission is indicated in the same slot, the UE performs reception of the PDCCH or downlink signal in the corresponding slot, and thus the corresponding slot is not configured to the same TDW to perform joint channel estimation. Therefore, when the UE determines slot #1 and slot #2 as different TDWs and performs PUSCH repetition transmission, it may not be necessary to satisfy the condition for joint channel estimation.

In case the UE is configured to monitor PDCCH in flexible symbols or receive downlink signals, the method of determining TDW according to whether the corresponding symbol overlaps with a symbol indicating PUSCH transmission as dynamic scheduling through DCI format 0_0, 0_1 or 0_2 may be applied starting from a slot after the first slot in which dynamically scheduled PUSCH transmission starts is excluded. In other words, in the case where the base station dynamically performs PUSCH scheduling for the UE, when the base station designates the first slot in which dynamically scheduled PUSCH transmission starts, the UE may assume that the base station has performed scheduling for the UE while excluding slots or symbols in which the UE is configured to perform monitoring or receive downlink signals. Thus, in a slot indicated by a K2 value corresponding to an offset value between a slot receiving a PDCCH and a slot where the UE transmits a PUSCH, the UE may configure the same TDW for subsequent consecutive uplink slots and consecutive non-downlink slots, regardless of whether the UE is configured to monitor whether symbols of the PDCCH or the received downlink signal overlap with symbols of the PUSCH transmitted through DCI format 0_0, 0_1 or 0_2.

On the other hand, the base station may intentionally configure the UE with an overlap according to the scheduling of the base station even from the first slot. Thus, in case the UE is configured to monitor PDCCH in flexible symbols or receive downlink signals, the method of determining TDW according to whether the corresponding symbol overlaps with a symbol in which PUSCH transmission is indicated as dynamic scheduling by DCI format 0_0, 0_1 or 0_2 may be applied starting from a slot including the first slot from which dynamically scheduled PUSCH transmission starts.

When the channel for joint channel estimation corresponds to PUSCH or PUCCH repetition transmission in the second method, the TDW length may be applied starting from a slot where the corresponding repetition transmission starts. Here, PUSCH repetition transmission may include: PUSCH repetition transmission type a or PUSCH repetition transmission type B including the same TB. In addition, the PUCCH repeated transmission may include the same UCI, and may include PUCCH repeated transmission transmitted in the same PUCCH format. In addition, when a channel for joint channel estimation includes one TB and PUSCH having a TBs determined with reference to a plurality of slots is transmitted in the second method, the TDW length may be applied starting from a first slot from which a corresponding PUSCH transmission starts. In addition, when the channel for joint channel estimation includes one TB and PUSCH having a TBs determined with reference to a plurality of slots is repeatedly transmitted in the second method, the TDW length may be applied starting from a first slot where the corresponding PUSCH repetition transmission starts.

In the second method, consecutive uplink slots and consecutive non-downlink slots may include a maximum of X slots/symbol of the gap between consecutive slots. Here, the X slots/symbols of the gap may include slots/symbols not used for uplink transmission. That is, the UE may determine the TDW with reference to a discontinuous uplink slot or a discontinuous non-downlink slot including X slots/symbol. X may be a value configured from the base station.

In the second method, when explicit information of the TDW is not received and thus the TDW (length) is determined based on the implicit information, a single TDW may be applied to too many slots. Here, the TDW (length) may be determined based on the number of times (e.g., N) of PUCCH or PUSCH repeated transmission, or may be configured based on a slot configuration. For example, the TDW (length) may be determined based on a time domain interval (e.g., slot interval/number) in which PUSCH or PUCCH retransmission is indicated, and/or may be determined based on consecutive uplink slots or consecutive non-downlink slots (including uplink channel (repeated) transmissions). When a single TDW is applied to too many slots, the complexity of the UE or the base station may be increased. Thus, a single TDW may be divided into multiple sub-TDWs. Here, joint channel estimation is possible for PUSCH or PUCCH included in the sub-TDW. Here, the sub TDW corresponds to a final/individual TDW. The UE may divide a single TDW into a plurality of sub TDWs based on the following information.

According to the first information, a single TDW may be divided into a plurality of sub-TDWs based on sub-TDW lengths. The UE may receive information about the length of one sub-TDW and divide the TDW into as many sub-TDWs as the corresponding length. The length may include the number of slots, the number of symbols, or the number of repeated transmissions. More specifically, the TDW may include N slots/symbols/repetitions (slot/symbol/repetition 0, slot/symbol/repetition 1, …, and slot/symbol/repetition N-1), and the sub-TDW length may be given as M slots/symbols/repetitions. In this case, the UE may determine one sub-TDW by grouping slot/symbol/repetition 0, slot/symbol/repetition 1, …, and slot/symbol/repetition M-1, another sub-TDW by grouping slot/symbol/repetition M, slot/symbol/repetition m+1, …, and slot/symbol/repetition 2*M-1, …, and another sub-TDW by grouping slot/symbol/repetition k×m, slot/symbol/repetition k×m+1, …, and slot/symbol/repetition N. Here, the slot/symbol/repetition included in the last sub-TDW may be less than M slots/symbols/repetitions. Here, k=floor (N/M).

According to the second information, a single TDW may be divided into a plurality of sub TDWs based on the number of sub TDWs. The UE may receive information about the number of sub-TDWs corresponding to the single TDW and divide the single TDW into as many sub-TDWs as the number of received sub-TDWs. More specifically, the TDW may include slots/symbols/repetitions (slot/symbol/repetition 0, slot/symbol/repetition 1, …, and slot/symbol/repetition N-1), and the number of sub-TDWs may be given as M. In this case, in one method, the number of slots/symbols/repetitions included in one sub-TDW may be ceil (N/M) or floor (N/M). More specifically, the N mod M sub-TDW may include ceil (N/M) slots/symbols/repetitions, and the M- (N mod M) sub-TDW may include floor (N/M) slots/symbols/repetitions. In another method, the number of slots/symbols/repetitions included in M-1 sub-TDWs may be floor (N/M), and the number of slots/symbols/repetitions included in one sub-TDW may be N- (M-1) floor (N/M).

According to the third information, a single TDW may be divided into a plurality of sub-TDWs based on a maximum interval. Here, the maximum interval is a maximum time domain interval in which the UE can maintain a condition enabling the base station to perform joint channel estimation, and may be determined according to the UE capability. That is, the maximum interval may mean a maximum time interval in which the UE can maintain phase continuity and power identity/consistency of the DMRS according to UE capability. Thus, the maximum interval may not be a value explicitly configured from the base station. The unit of maximum interval may include the number of slots/symbols/repetition. UE capabilities may be provided by the UE to the base station (e.g., initial access procedures). When the TDW length (e.g., a time domain interval indicating PUSCH or PUCCH repeated transmission, or the number of consecutive uplink slots or consecutive non-downlink slots) determined based on the implicit information exceeds the maximum interval in the second method, the UE may divide the TDW into sub-TDWs with reference to the maximum interval. Thus, it can be understood that the sub-TDW (or final TDW) can be determined based on a smaller value between (a) the TDW length determined based on implicit information according to the second method and (b) the maximum interval corresponding to the maximum interval that can be configured by the UE (according to UE capabilities). Specifically, it is assumed that the TDW includes N slots/symbols/repetitions (slot/symbol/repetition 0, slot/symbol/repetition 1, …, slot/symbol/repetition N-1), and the maximum interval is M slots/symbols/repetitions. Here, in case of M < N, the UE may determine one sub-TDW by grouping slot/symbol/repetition 0, slot/symbol/repetition 1, …, and slot/symbol/repetition M-1, determine another sub-TDW by grouping slot/symbol/repetition M, slot/symbol/repetition m+1, …, and slot/symbol/repetition 2*M-1, …, and determine another sub-TDW by grouping slot/symbol/repetition (k-1) x M, slot/symbol/repetition (k-1) x m+1,. Here, the slots/symbols/repetitions included in the last sub-TDW may be less than M slots/symbols/repetitions. Here, k=floor (N/M).

Fig. 58 and 59 illustrate uplink channel transmissions according to examples of the present disclosure.

Referring to fig. 58, the ue may perform (repeated) transmission of an uplink channel on a set of slots (S5802). In addition, the UE may transmit DMRS of (repeated) transmission of the uplink channel on the set of slots (S5804). In this case, when the joint channel estimation operation is configured (S5806), the DMRS may be transmitted through a plurality of consecutive slots within a time window (e.g., TDW) such that phase continuity and power consistency are maintained (S5806 a). In this case, the base station may perform joint coding channels based on DMRS on a plurality of consecutive slots within the time window. Demodulation performance of the uplink channel can be enhanced and coverage can be improved based on the result of joint coding of the channels. When the length of the time window is not configured by the base station (e.g., there is no explicit indication) (S5808), the time window (e.g., the length of the time window) may be determined based on the following information (S5808 a). For example, the length of the time window may be determined based on the smaller of the following values:

(1) A number N of time slots comprising uplink channel transmissions; and

(2) Wherein the UE is able to maintain a maximum number M of slots of phase continuity and power consistency depending on the UE capability.

Referring to FIG. 59, the length of the time window may be determined based on M in the case M < N, and N in the case M+.N (FIG. 59 b).

When the joint channel estimation operation is not configured (S5806), the DMRS may be used for slot-based individual channel estimation (S5806 b). In addition, when the length of the time window is configured by the base station (e.g., higher layer signaling) (S5808), the length of the time window may be determined to be configured by the base station (S5808 b).

Here, N may correspond to the number of slots from the slot at which the (repeated) transmission of the uplink channel starts to the slot at which the (repeated) transmission of the uplink channel ends. In addition, N may correspond to the number of consecutive time slots for (repeated) transmission of the uplink channel. In addition, the uplink channel may include PUCCH repeated transmission or PUSCH repeated transmission. In addition, the uplink channel may include a PUSCH retransmission type A, PUSCH retransmission type B, a PUSCH transmission with a Transport Block Size (TBS) determined with reference to a plurality of slots, or a PUSCH retransmission with a TBS determined with reference to a plurality of slots.

Next, a method for determining a time slot in which a UE applies TDW so that a base station can perform joint channel estimation is described. When the UE determines the length of the TDW according to the first and second methods, a time slot in which the UE applies the TDW may be determined as follows.

-A physical time slot based determination method: the UE may determine a time slot to apply TDW based on the physical time slot. In particular, the UE may apply the TDW length determined according to the first and second methods during consecutive physical slots starting from a point of time at which the TDW starts.

For example, referring to fig. 51a, the ue may be configured to repeatedly transmit PUSCH during slots from slots # 0to 4. In addition, according to the first method, the TDW length may be explicitly indicated as four slots. Thus, the UE may determine one of four slots corresponding to slot #0, slot #1, slot #2, and slot # 3. In this case, PUSCH transmission is impossible in slot #0, and thus the UE may defer and perform PUSCH retransmission. However, the TDW is based on four physical slots starting from a point of time at which PUSCH retransmission is instructed to start, and thus PUSCH retransmission in slot #4 may not include the same TDW. That is, actual PUSCH repetition transmission from the UE is performed in slot #1, slot #2, slot #3, and slot #4, but joint channel estimation by the base station is performed in slot #0, slot #1, slot #2, and slot #3, and thus it is difficult to acquire gain through joint channel estimation for PUSCH repetition transmission in slot # 4. The UE may maintain/satisfy conditions (e.g., phase continuity and power consistency) that enable the base station to perform joint channel estimation with reference to the TDW. In this case, the UE may maintain joint channel estimation conditions in slot #0, slot #1, slot #2, and slot # 3. Accordingly, the UE may perform PUSCH transmission only in slots #1, #2, and #3 where actual PUSCH repetition transmission occurs to maintain joint channel estimation conditions, and may transmit PUSCH transmitted in delayed slot #4 to the base station regardless of the joint channel estimation conditions.

For example, referring to fig. 51b, the ue may be configured to repeatedly transmit PUSCH for four slots starting from slot # 0. In addition, according to the second method, the length of the TDW may be determined with reference to consecutive uplink slots. Therefore, the UE may determine five slots corresponding to slot #0, slot #1, slot #2, slot #3, and slot #4 as one TDW. In this case, PUSCH transmission is impossible in slot #0, and thus the UE may defer PUSCH repetition to slot #4 and perform transmission. However, the TDW is based on consecutive uplink slots starting from a point of time at which PUSCH retransmission is instructed, and thus slot #0, which does not include actual PUSCH retransmission, may be included in the TDW. That is, the UE performs actual PUSCH repetition transmission in slot #1, slot #2, slot #3, and slot #4, but slot #0, slot #1, slot #2, slot #3, and slot #4 are determined to have the same TDW. Thus, when another uplink signal/channel transmission is indicated in slot #0, it may be difficult for the UE to satisfy the condition of joint channel estimation. The UE may maintain/satisfy conditions (e.g., phase continuity and power consistency) for enabling the base station to perform joint channel estimation with reference to the TDW. In this case, the UE may maintain joint channel estimation conditions in slot #0, slot #1, slot #2, slot #3, and slot # 4. Thus, the UE may perform PUSCH transmission to maintain joint channel estimation conditions in slot #1, slot #2, slot #3, and slot #4 in which actual PUSCH retransmission occurs. Thus, for PUSCH transmitted in delayed slot #4, the UE may transmit PUSCH to the base station while maintaining joint channel estimation conditions. However, for other uplink signal/channel transmissions, it is difficult to satisfy the conditions that enable the base station to perform joint channel estimation. Thus, for uplink signal/channel transmission other than the same PUSCH repetition transmission in slot #0, the UE may perform uplink signal/channel transmission to the base station regardless of conditions for enabling joint channel estimation.

-A method of determination based on available time slots: the UE may determine the time slot in which the TDW is applied based on the time slot in which PUSCH transmission is possible. Specifically, the UE may apply the TDW length determined according to the first and second methods to a time slot in which an actual PUSCH transmission is possible from a time point at which the TDW starts. Here, a slot in which PUSCH transmission is possible refers to a slot in which time and frequency domain resources configured or indicated for PUSCH transmission are available for PUSCH transmission in the corresponding slot. In other words, the time slot to which the TDW is applied may include only a time slot in which PUSCH transmission is possible among consecutive uplink time slots and consecutive non-downlink time slots.

For example, referring to fig. 52a, the ue may be configured to repeatedly transmit PUSCH for four slots starting from slot # 0. In addition, according to the first method, the TDW length may be explicitly indicated as four slots. In this case, the indicated PUSCH transmission is not possible in slot #0, and thus the UE may defer PUSCH repetition to slot #4 and perform transmission. In this case, the UE may determine the slots to which the TDW is applied as slot #1, slot #2, slot #3, and slot #4 with reference to the slots in which the actual PUSCH retransmission is possible. In this method, all PUSCH repetition transmissions are included in the same TDW, and thus performance enhancement can be expected by joint channel estimation of uplink PUSCH transmissions by the base station. The UE maintains/performs conditions (e.g., phase continuity and power consistency) for enabling the base station to perform joint channel estimation with reference to the slots included in the TDW. In this case, the UE may perform transmission in slot #1, slot #2, slot #3, and slot #4 in which the actual PUSCH repetition transmission occurs, while maintaining the joint channel estimation condition. That is, the UE may transmit PUSCH to the base station while maintaining joint channel estimation conditions in slot #4 so that the base station can also perform joint channel estimation on PUSCH transmitted in delayed slot #4.

For example, referring to fig. 52b, the ue may be configured to repeatedly transmit PUSCH for four slots starting from slot # 0. In addition, according to the second method, the TDW length may be determined with reference to consecutive uplink time slots. Here, the TDW length according to the second method may be from slot #0 to slot #4. In this case, PUSCH transmission is impossible in slot #0, and thus the UE may defer PUSCH repetition to slot #4 and perform transmission. The UE may determine the slots to which the TDW is applied to be slot #1, slot #2, slot #3, and slot #4 with reference to slots in which actual PUSCH repetition transmission including the same TB is possible. In this method, only PUSCH repeated transmissions including the same TB are included in the same TDW except for another uplink signal/channel, and thus the condition of joint channel estimation can be satisfied. The UE may perform conditions (e.g., phase continuity and power consistency) that enable the base station to perform joint channel estimation with reference to the time slots included in the TDW. In this case, the UE may perform PUSCH transmission while maintaining joint channel estimation conditions in slot #1, slot #2, slot #3, and slot #4 where actual PUSCH repetition transmission including the same TB occurs. That is, the UE may transmit PUSCH while also maintaining joint channel estimation conditions in slot #4, so that the base station can perform joint channel estimation for PUSCH transmitted in delayed slot #4. However, in the case of another uplink signal/channel transmission, the UE performs uplink signal/channel transmission to the base station, except for PUSCH repetition transmission including the same TB within the TDW length determined with reference to consecutive uplink slots according to the second method, regardless of conditions for enabling the base station to perform joint channel estimation.

Frequency hopping and joint channel coding

In the above description, during frequency hopping of the UE, a specific number M corresponding to a frequency hopping interval that may be included in one frequency hopping and a TDW length corresponding to a time interval for joint channel estimation may be separately configured. For convenience of description, TDW configured explicitly or implicitly (base station) is hereinafter referred to as L.

The base station may configure for the UE whether DMRS used for PUSCH or PUCCH transmission of the UE is bundled, so that the base station can perform joint channel estimation when the UE transmits PUSCH or PUCCH. That is, the UE may be configured by the UE such that DMRS Bundling for PUSCH or PUCCH transmission is enabled (DMRS-bundling=enabled) or disabled (DMRS-bundling=disabled). When "DMRS-bundling=enabled" is configured, the UE may transmit PUSCH or PUCCH to the base station while satisfying a condition for enabling the base station to perform joint channel estimation. When the "DMRS-bundling=disabled" is configured, the UE may transmit PUSCH or PUCCH to the base station, regardless of conditions for enabling the base station to perform joint channel estimation. In this disclosure, the terms "joint channel coding" and "DMRS bundling" may be used interchangeably.

Configuring DMRS bundling enablement or disablement for PUSCH or PUCCH transmissions such that the base station performs joint channel estimation for PUSCH or PUCCH transmissions performed by the UE may be performed explicitly or implicitly separately from the TDW length L described above.

The UE may need to determine the TDW and slot index (repeated transmission slot index) for frequency hopping according to whether M and L are configured. For example, the UE may be configured to enable joint channel estimation and transmit PUSCH or PUCCH via inter-slot hopping. In this case, the UE may need to determine a value to be applied as the TDW length and slot index for frequency hopping according to a value configured between M and L from the base station. Here, the slot index for frequency hopping may be determined independently of joint channel estimation. That is, the UE may perform PUSCH or PUCCH transmission to the base station regardless of conditions for enabling the base station to perform joint channel estimation within the same frequency hopping. Specifically, the UE may perform PUSCH or PUCCH transmission to the base station without maintaining phase continuity and power identity/consistency through DMRS of multiple slots/symbols/repetitions within the same frequency hopping.

-Case where both M and L are configured: the slot index for frequency hopping may be determined based on M, and the TDW length for joint channel estimation may be determined based on L.

-Case of M configured and L not configured: the slot index for frequency hopping may be determined based on M, and the TDW length may be determined based on a TDW default value. Here, the TDW default value may be a smaller value between (a) a maximum interval corresponding to a maximum interval at which the UE can configure the base station to perform joint channel estimation (based on UE capability) and (b) a timer domain interval (a) indicating PUSCH or PUCCH retransmission.

-Case of not configuring M and configuring L: the slot index for frequency hopping may be determined based on L, and the TDW length may be determined based on L.

-Case where neither M nor L are configured: the slot index for frequency hopping may be determined based on a single slot (m=1), and the TDW length may be determined based on the TDW default value described above.

When neither M nor L is configured, the UE determines a slot index for frequency hopping based on a single slot, and thus PUSCH or PUCCH transmissions in consecutive slots may be mapped to different frequency hops. Thus, it may be difficult to maintain phase continuity and power identity/consistency between PUSCH or PUCCH transmissions in consecutive slots. Accordingly, even if DMRS Bundling for joint channel estimation for PUSCH or PUCCH transmission performed by a base station is configured to be enabled (DMRS-bundling=enabled), coverage enhancement of uplink transmission according to joint channel estimation can be acquired.

Hereinafter, UE operation for solving this problem is proposed. In this case, the UE operation may vary according to whether DMRS Bundling for performing joint channel estimation by the base station for PUSCH or PUCCH transmission performed by the UE is enabled (DMRS-bundling=enabled) or disabled (DMRS-bundling=disabled). UE operation according to each case is proposed.

(1) First method

- "DMRS-bundling=disabled": when DMRS bundling is disabled, a slot index for frequency hopping may be determined based on a single slot, and a TDW length may be determined based on a TDW default value. Here, the TDW default value may be a smaller value between (a) a maximum interval corresponding to a maximum interval that the UE can configure to enable the base station to perform joint channel estimation and (b) a timer domain interval indicating PUSCH or PUCCH retransmission. When configuring "DMRS-bundling=disabled", the UE may be configured by the base station such that coverage enhancement by joint channel estimation in the base station takes precedence over frequency diversity gain by frequency hopping between PUSCH or PUCCH transmissions. Thus, the slot index for frequency hopping can be determined based on a single slot.

- "DMRS-bundling=enabled": when DMRS bundling is enabled, both the TDW length and the slot index for frequency hopping may be determined based on the TDW default value. This method corresponds to a method of maximizing coverage enhancement through joint channel estimation in a base station by determining a TDW length and a slot index for frequency hopping based on a maximum interval at which a UE can maintain channel estimation conditions when "DMRS-bundling=enabled" is configured by the base station.

However, in the case of "DMRS-bundling=enabled" of the first method, even if the UE is configured by the base station to transmit PUSCH or PUCCH by using inter-slot hopping, the UE determines a slot index for hopping based on the TDW default value, and thus the UE may not perform hopping between PUSCH or PUCCH transmissions. Coverage enhancement by joint channel estimation is possible, but it is difficult to expect frequency diversity gain by frequency hopping. Therefore, a method of acquiring not only coverage enhancement by joint channel estimation but also frequency diversity gain by frequency hopping is proposed.

(2) Second method

- "DMRS-bundling=disabled": when DMRS bundling is disabled, a slot index for frequency hopping may be determined based on a single slot, and a TDW length may be determined based on a TDW default value of the first method. When configuring "DMRS-bundling=disabled", the UE may be configured by the base station such that the frequency diversity gain by frequency hopping between PUSCH or PUCCH transmissions is prioritized over coverage enhancement by joint channel estimation in the base station. Thus, the slot index for frequency hopping can be determined based on a single slot.

- "DMRS-bundling=enabled": when DMRS bundling is enabled, a TDW length may be determined based on a default value, and a slot index for frequency hopping may be determined such that frequency hopping can be performed at least once based on half of the TDW default value. In this method, when the base station configures "DMRS-bundling=enabled" for the UE, the UE may perform frequency hopping on PUSCH or PUCCH transmission within the same TDW at least once by determining a TDW length based on a maximum interval in which the UE can maintain joint channel estimation conditions, and determining a slot index for frequency hopping based on half of a TDW default value. Thus, by this method, not only coverage enhancement by joint channel estimation but also frequency diversity gain by frequency hopping can be obtained.

TDW determination for joint channel estimation

Next, in the present disclosure, a method of determining TDW for joint channel estimation by a UE when both M and L are configured and L < M is described.

Referring to fig. 57, the ue may receive a configuration/indication for repeatedly transmitting PUCCH k=4 times from slot #1 to slot #4 from the base station, and may be configured with m=4 and l=2. That is, the UE may repeat transmission of four possible slots according to the PUCCH therein starting from the first slot indicating PUCCH transmission with the same hopping frequency, and may determine the same TDW of two consecutive slots starting from the first slot indicating PUCCH transmission. In this case, PUCCH repeated transmission of slot #1 and slot #2 and PUCCH repeated transmission of slot #3 and slot #4 are performed in the same frequency hopping, and thus joint channel estimation is possible in the base station. However, PUCCH repeated transmission of slot #1 and slot #2 and PUCCH repeated transmission of slot #3 and slot #4 are determined to have different TDWs, and thus the UE does not need to satisfy joint channel estimation conditions when performing PUCCH repeated transmission. In addition, even if the UE performs PUCCH repeated transmission by satisfying joint channel estimation conditions in different TDWs, the base station may not perform joint channel estimation on PUCCH repeated transmission performed in different TDWs. This is because the base station expects the UE to transmit PUCCH within TDW while satisfying joint channel estimation conditions.

Hereinafter, although an example for solving performance degradation according to configuration of L < M is described, under the assumption that a base station is configured with M and L smaller than a value of a maximum interval corresponding to a maximum interval that can be configured for the UE (according to a value configured for the UE) so that the base station can perform joint channel estimation, the UE transmits PUSCH or PUCCH within M slots so that the base station can perform joint channel estimation, and the base station can obtain coverage enhancement of uplink transmission according to joint channel estimation by using this.

According to a first example of the present disclosure, a UE may expect that L < M may not be configured by a base station if the base station knows the UE capabilities such as the maximum interval associated with joint channel estimation. That is, in order to prevent this problem from occurring, the base station may configure the UE via scheduling such that the value of L is always equal to or greater than the value of M, and the UE may expect to receive a configuration in which L is equal to or greater than the value of M from the base station by RRC signaling. According to the first example, the value of M is a value equal to or less than L, and thus the UE may transmit PUSCH or PUCCH determined to have the same slot index for frequency hopping while maintaining phase continuity and power consistency, so that the base station can perform joint channel estimation, and the base station may enhance channel estimation performance by joint channel estimation to obtain coverage enhancement of uplink transmission. However, the first example may impose restrictions on scheduling of the base station, and thus a method for solving this problem is described below.

According to a second example, when the UE receives a configuration of L < M from the base station, the UE may determine TDW based on the value of M. That is, in order to maximize the gain through joint channel estimation in the above-described problem situation, the UE may determine the TDW based on a specific number M values that are hopping intervals that can be included in one hopping frequency while ignoring the L values configured for the UE. The slot index for frequency hopping described above may be determined based on the value of M, regardless of joint channel estimation, but to solve this problem, the value of M may be used to determine the TDW for joint channel estimation. According to a second example, the UE may transmit PUSCH or PUCCH to the base station by maintaining phase continuity and power consistency to enable the base station to perform joint channel estimation within the same slot index used for frequency hopping based on the configured value of M, and the base station may enhance channel estimation performance by joint channel estimation to obtain coverage enhancement of uplink transmission.

For example, referring to fig. 57, l=2 is configured for the base station, but is a value smaller than the configuration value of M (=4), the UE may use m=4 for TDW determination according to the second example. Accordingly, PUCCH repeated transmissions of slot #1, slot #2, slot #3, and slot #4 are included in the same TDW, and thus the UE may transmit PUCCH to the base station by maintaining phase continuity and power consistency of DMRS over a plurality of slots to enable the base station to perform joint channel estimation.

In the first and second examples, it is assumed that for the UE, M and L are configured to be smaller than a value of a maximum interval corresponding to a maximum interval at which the UE can configure to enable the base station to joint channel estimation according to a value configured for the UE. However, if not, i.e., if M is configured to be greater than the maximum interval, the UE may perform uplink transmission to the base station by maintaining phase continuity and power consistency of the DMRS based on a value L configured by the base station to enable the base station to perform joint channel estimation, and the base station may enhance channel estimation performance by joint channel estimation to obtain coverage enhancement of the uplink transmission.

In the first and second examples, it is assumed that for the UE, M and L are configured to be smaller than a value of a maximum interval corresponding to a maximum interval at which the UE can perform joint channel estimation according to a value configured for the UE. But if not, i.e., if the value of M is configured to be greater than the maximum interval, the UE may perform uplink transmission to the base station by maintaining phase continuity and power consistency of the DMRS based on the maximum interval corresponding to the maximum interval that enables the base station to perform joint channel estimation according to the value configured for the UE, and the base station may enhance channel estimation performance by joint channel estimation to obtain coverage enhancement of the uplink transmission.

Reference subcarrier spacing (SCS) of TDW

In the present disclosure, TDW (length) may be defined by the number of symbols/slots/repetitions. In NR systems, there may be various SCS, and thus the symbol/slot/repetition varies according to SCS. Therefore, SCS for determining TDW may be required. This is called the reference SCS of TDW. The method for determining the reference SCS of the TDW is as follows.

As a first method, when receiving a TDD configuration of a cell, a UE receives a configuration of a reference SCS for the TDD configuration. The UE may use the TDD configured reference SCS of the cell as the reference SCS of the TDW when determining the TDW. Thus, the UE does not need a separate configuration of the reference SCS of the TDW.

As a second method, when receiving the configuration of one or more UL BWP of a cell, the UE receives the configuration of SCS of the one or more UL BWP. The UE may use one of SCSs configured for one or more UL BWP of the cell as a reference SCS for the TDW when determining the TDW. Preferably, when a plurality of UL BWPs are configured, the lowest SCS may be used as the SCS of the TDW.

As a third method, the UE may use SCS of the activated UL BWP as a reference SCS of the TDW when UL BWP of each cell is active.

As a fourth method, the UE may use any SCS as a reference SCS for the TDW. Here, any SCS may be differently determined for each Frequency Range (FR). Preferably, any SCS may be one of the SCSs available in each FR and may be the lowest SCS. For example, in the case of FR1, 15kHz, 30kHz and 60kHz can be used for SCS, and thus 15kHz can be used as a reference SCS for TDW. In the case of FR2, 60kHz and 120kHz can be used for SCS, and 60kHz can be used as a reference SCS for TDW.

The first to fourth methods are cases where the UE does not receive a configuration of a separate reference SCS to determine the TDW. However, the base station may configure the reference SCS of the cell for the UE. The fifth method corresponds to a case where the UE configures a reference SCS for the UE. In such a case, the UE may expect the reference SCS to satisfy at least the following conditions: the reference SCS of the TDW configured for the UE in the cell is at least not larger than the SCS configured for the UL BWP of the cell.

Information transmission about TDW

In the above description, a method for determining a TDW by a UE based on explicit information or implicit information of the TDW received from a base station is described. Hereinafter, a method in which the TDW is determined and applied by the UE itself and then information about the TDW is transmitted to the base station is described.

As a first method, information about the start and end of TDW may be transmitted. For example, the UE may indicate a value of "0" (or "1") of 1 bit to the PUSCH or PUCCH transmitted in the symbol sets of the start and end of the TDW, and may indicate a value of "1" (or "0") of 1 bit to the PUSCH or PUCCH transmitted in the symbol sets other than the start or end of the TDW. Here, the symbol set may include a slot, a symbol, and a repeated transmission. For example, when it is assumed that TDW starts at slot n and ends at slot n+3, a value of "0" of 1 bit may be indicated to PUSCH or PUCCH transmitted in slot n, and a value of "1" of 1 bit may be indicated to PUSCH or PUCCH transmitted in slots n+1, n+2, and n+3. Here, when a value of 1 bit is indicated to the PUSCH, the 1 bit is multiplexed with the PUSCH and transmitted. In this case, 1 bit may be multiplexed with PUSCH in the same method as HARQ-ACK.

As a second method, information about the TDW may be transmitted by switching the TDW when the TDW is changed. For example, the UE may transmit a value of "0" of 1 bit in PUSCH or PUCCH transmitted in a symbol set in one TDW, and may transmit "1" by switching a corresponding value of 1 bit in PUSCH or PUSCH transmitted in a symbol set in the next TDW.

The problems of the first method and the second method are described by fig. 39. Ambiguity in the TDW may occur between the UE and the base station when the base station fails to receive PUSCH or PUCCH transmitted in the symbol set within the specific TDW indicated by the UE. Referring to fig. 39a, the ue may indicate time slot 0/1/2/3 as one TDW and time slot 4/5 as another TDW according to a first method. In this case, when the base station fails to perform PUCCH or PUSCH reception of slot 3/4, the base station may attempt joint channel estimation by determining slots 0 to 5 as one TDW. Referring to fig. 39b, the ue may indicate a slot 0/1/2 as one TDW, a slot 3/4 as another TDW, and a slot 5 as another TDW. In this case, when the base station fails to perform PUCCH or PUSCH reception of slot 3/4, the base station may attempt joint channel estimation by determining slots 0 to 5 as one TDW. However, the UE may transmit the PUCCH or PUSCH without satisfying joint channel estimation conditions in different TDWs, and thus the base station may not perform joint channel estimation, and may have difficulty in enhancing coverage performance. Accordingly, a method for reducing ambiguity of information about TDW between UE and base station is needed.

According to a first example of the present disclosure, the UE may transmit information about the TDW to the base station by using the counter indicator. The UE may transmit information on the order in which the symbol sets of the PUCCH or PUSCH are transmitted in one TDW. Here, the symbol set may include a slot, a symbol, and a repeated transmission. For example, referring to fig. 40a, when the UE expects to indicate that joint channel estimation is possible from slot 0 to slot 3 and joint channel estimation is possible from slot 4 to slot 5, the UE may indicate a value of 0 to the starting slot in which joint channel estimation is possible and a value of 1, 2, and 3 to the following slots in ascending order. In addition, referring to fig. 40b, when the UE expects to indicate that joint channel estimation is possible from slot 0 to slot 2 and joint channel estimation is possible from slot 3 to slot 4, the UE may indicate a value of the starting slot indicator to which joint channel estimation is possible, and may indicate a value of the counter indicator to subsequent slots in ascending order. Thus, in fig. 40a and 40b, when the base station has failed to decode the uplink transmission of slot 3/4, the base station may also identify, via the counter indicator, that joint channel estimation cannot be performed on the uplink transmissions of slot 2 and slot 5.

According to the (1-1) th example, the UE may transmit information about the counter indicator and the total indicator as information for joint channel estimation. That is, information about the TDW may be indicated as [ counter indicator, total indicator ]. The total indicator may be a set of symbols included in one TDW. Here, the symbol set may include a slot, a symbol, and a repeated transmission. For example, referring to fig. 41, when the base station fails to receive uplink transmissions of slot 2 and slot 3, ambiguity may occur even with the counter indicator of the first example. Thus, by indicating both the counter indicator and the total indicator, ambiguity in the TDW between the UE and the base station can be reduced. This method reduces ambiguity of TDW between the UE and the base station when the base station fails to receive an uplink channel transmitted by the UE, and thus can acquire a coverage gain by enhancing joint channel estimation performance.

According to a second example of the present disclosure, a TDW index may be transmitted. In a first example, different counter values are sent for respective slots in the same TDW, and thus signaling overhead and complexity of the UE may be increased. Thus, one TDW may be identified as the same index and the index sequentially increases as the TDW changes to the next TDW to indicate a different TDW. For example, referring to fig. 42, the ue may notify uplink transmission in the same TDW by an index of the TDW, and may notify a different TDW by increasing the index when the TDW changes. The advantage of this approach is that when the uplink transmission within a particular TDW has failed (slot 3 and slot 4), the base station can be scheduled to identify the failure and perform retransmissions as shown in fig. 42 b.

TDW determination when configuring multiple cells

Next, in the present disclosure, a method for determining TDW when configuring a plurality of cells (e.g., uplink cells) for a UE is described.

The UE may receive a configuration of a plurality of uplink cells from the base station. When multiple uplink cells are configured for a UE, they are referred to as UL Carrier Aggregation (CA). The cell originally configured for the UE is referred to as a primary cell (PCell), and the cells configured other than the PCell are referred to as secondary cells (scells). The UE may transmit an uplink physical channel in the PCell and/or SCell. Here, the uplink physical channel may include at least one of PUSCH and PUCCH. When transmitting an uplink physical channel in a plurality of cells within the same frequency band, the UE may share transmission power to the plurality of cells and perform transmission.

When the UE performs uplink transmission in a plurality of cells, the base station may perform joint channel estimation using DMRS of an uplink channel. Thus, when configuring multiple uplink cells, the UE may be configured to meet the joint channel estimation conditions described above. In the above decryption, a method for the UE to receive a configuration of one TDW from the base station and apply uplink channel transmission is described. When the UE has received the configuration of one TDW in the (UL) CA case, the following problem may occur in determining TDWs in a plurality of cells. Here, one TDW may be a TDW of a (uplink) PCell configuration of a reference UE.

First, the UE may have different TDD configurations for multiple cells. Here, TDD configuration refers to a case where a specific symbol is configured as at least one of a downlink symbol, an uplink symbol, and a flexible symbol from a base station. In this case, the TDW of the reference PCell configuration may not be the best TDW for joint channel estimation in the SCell. For example, referring to fig. 43, the ue has received two cells, cell #0 and cell #1, and may have different TDD configurations for the cells, respectively. In this case, it is assumed that the UE has received the configuration of the TDW of the reference cell #0 and applies the TDW every five slots starting from the first slot within the radio frame. The number of consecutive UL slots in cell #1 is 6, but TDW is applied every five slots, and thus TDW may not be the best TDW for cell # 1.

Next, the UE may have different SCS configurations for multiple cells. Here, the SCS may include at least one of an SCS for TDD configuration and an SCS for BWP configuration. In the CA case, when the SCS of the TDD configuration for the SCell is smaller than the SCS of the TDD configuration for the PCell, the boundary of the TDW determined with reference to the PCell may not be accurately applied. For example, referring to fig. 44, for SCS of TDD configuration for two cells, the UE has received a configuration in which SCS for cell #0 is 30kHz and SCS for cell #1 is 15 kHz. It is assumed that the TDW for joint channel estimation is indicated as 2.5ms or 5 slots from the first slot within the radio frame of the reference cell # 0. In this case, the UE may apply the same TDW to cell #1. In this case, the TDW boundary may be located during transmission of the uplink channel within the third U slot of cell #1. Thus, in the third U slot of cell #1, some symbols belong to the first TDW, while other symbols belong to the second TDW. That is, when the SCS of the TDD configuration for the SCell is smaller than that for the PCell, the TDW may not be accurately applied. Thus, in the CA case, the TDW needs to be accurately determined for all cells configured for the UE.

Next, an example for solving the problem of determining TDW in the (UL) CA case is described.

According to a first example of the present disclosure, for a plurality of cells, a UE may receive a configuration of a separate TDW for each cell. When multiple cells are configured for a UE, a separate TDW may be configured for each cell. That is, when the number of cells including PCell configured for the UE is N, the UE may receive the configuration of N TDWs applied to the corresponding cells. For example, for (cell #0, cell #1,.+ -. Cell #n-1), the UE may receive the configuration of (window #0, window #1,..+ -. Window #n-1) respectively. For example, referring to fig. 45, the ue may receive the configuration of tdw#0 (=2 slots (=1 ms) of 30kHz SCS) of cell#0 and tdw#1 (=2 slots (=2 ms) of 15kHz SCS) of cell#1. Here, the method for configuring the TDW of each cell may be determined according to the above-described TDW configuration method for one cell.

In the case of the above-described (UL) CA, the configuration of the individual TDW of each cell is assumed in the first example. However, the base station may use some parameters as cell common parameters to reduce signaling overhead. The method is as follows.

As a first method, a common TDW reference SCS (simply referred to as a reference SCS) may be used for the corresponding cells. That is, the base station may configure one reference SCS for the UE, and the UE may implicitly infer only one reference SCS. The UE may apply one reference SCS to all cells. For example, in fig. 45 above, the SCS of the TDW of cell #0 is 30kHz and the SCS of the TDW of cell #1 is 15kHz. In this case, as in fig. 45, when the SCS of the TDW is configured to be high, the boundary of the TDW may be positioned in the middle of the slot with the low SCS. The method of preventing this is as follows. The UE may obtain TDW SCS in each cell. The UE may select one of the TDW SCSs of each cell and use it as a reference SCS for all cells. In this case, the lowest TDW SCS among the TDW SCSs of each cell may be selected as the reference SCS. In another example, TDW SCS of PCell in the corresponding cell may be selected as the reference SCS. In another example, the TDW SCS of the cell having the lowest index among the corresponding cells may be selected as the reference SCS. In another example, the UE may receive a configuration of one reference SCS for TDW of all cells from the base station. At this time, the value of the reference SCS configured for the UE needs to have a CSC not greater than the UL BWP configured for all cells.

As a second method, the UE may commonly receive one TDW length without receiving a configuration of the TDW length for each cell. In this case, when one TDW length is commonly configured, the TDW length is referred to as a cell common TDW length. The UE may apply the cell common TDW length to the corresponding cell. For example, the UE may adjust the cell common TDW length according to the reference SCS and SCS of the cell and apply it to each cell. That is, when the cell common TDW length corresponds to M slots/symbols/repetition, the TDW length applied to one cell can be obtained as follows.

Tdw=f (M (scs_cell/scs_reference)) (slot/symbol/repetition)

Here, scs_refer represents a reference SCS, and scs_cell represents an SCS of a cell. F (x) may be at least one of ceil (x), floor (x), and round (x). Ceil (x) indicates a round-up function, flow (x) indicates a round-down function, and round (x) indicates a round function. M indicates a cell common TDW length.

For example, referring to fig. 46, assume a configuration in which the SCS of cell #0 is 30kHz SCS and the SCS of cell #1 is 15kHz SCS and the reference SCS (scs_refer) of both cells is 15 kHz. In addition, it is assumed that the cell common TDW length for joint channel estimation is indicated as five slots (starting from the first slot within the radio frame). In this case, according to the above equation, the TDW length applied to the cell #0 may be determined to be 5×30kHz/15 khz=10 slots/symbol/repetition, and the TDW length applied to the cell #1 may be determined to be 5×15kHz/15 khz=5 slots/symbol/repetition.

For example, referring to fig. 47, assume a configuration in which the UE has received a configuration in which the SCS of cell #0 is 30kHz SCS and the SCS of cell #1 is 15kHz SCS and the reference SCS (scs_refer) of both cells is 30 kHz. In addition, it is assumed that the cell common TDW length for joint channel estimation is indicated as five slots (starting from the first slot within the radio frame). In this case, according to the above equation (e.g., f (x) =ceil (x)), the TDW length applied to the cell #0 may be determined to be ceil (5×30kHz/30 kHz))=5 slots/symbol/repetition, and the TDW length applied to the cell #1 may be determined to be ceil (5×15kHz/30 kHz))=3 slots/symbol/repetition.

In the (UL) CA case, according to the second example of the present disclosure, the TDW determined in one cell may be extendedly applied to each cell. When configuring a plurality of cells, the UE may select one reference cell. Thereafter, the TDW configured with reference to the reference cell may be determined as the TDW for all cells. The criteria for determining the reference cell may include the following items.

PCell: one TDW may be a window determined with reference to the PCell. That is, the UE may extend the TDW determined with reference to the PCell according to the SCell and apply it.

-Lowest cell index: the cell with the lowest cell index may be determined as the reference cell. Here, the lowest cell index may be 0. That is, the PCell may be determined as a reference cell. Alternatively, the lowest cell index may be 1. That is, a cell having the lowest cell index among scells remaining after the PCell is excluded may be determined as a reference cell.

-Lowest SCS: the cell configured with the lowest SCS may be determined as the reference cell. Here, the SCS may include at least one of an SCS configured according to TDD and an SCS configured according to BWP of the UE. When a plurality of cells of the UE are respectively configured to have different SCSs, the TDW determined with reference to the cell configured with the highest SCS may not end at the slot boundary of the cell having the lowest SCS and may end within the slot. To prevent this, the UE may select a cell configured with the lowest SCS among the plurality of cells as a reference cell and apply the TDW of the corresponding cell to all cells. When there are multiple cells configured with the lowest SCS, the reference cell may be determined in conjunction with other criteria (e.g., cell index, TDD configuration periodicity, and UL slot ratio). For example, when there are two cells configured with the lowest SCS, a cell having the lowest cell index between the two cells may be selected as the reference cell.

-Longest TDD configuration periodicity: the cell with the longest TDD configuration period may be determined as the reference cell. The TDD configuration periodicity is referred to herein as the periodicity of one TDD configuration repetition (see, e.g., TS38.213 11.1). For example, referring to fig. 48, when SCS of TDD configuration for all cells is 15kHz, TDD configuration periodicity of cell #0 is 5ms, and TDD configuration periodicity of cell #1 is 10ms. In order to include as many UL slots as possible for a plurality of cells, the UE may determine a cell having the longest TDD configuration periodicity as a reference cell and apply TDWs of the corresponding cells to all cells. The TDD configuration periodicity of the cell #0 is 5 slots, and the TDD configuration periodicity of the cell #1 is 10 slots, so that the cell #1 can be selected as a reference cell, and the TDW of the cell #1 can be applied to all cells. When there are multiple cells with the longest TDD configuration periodicity, the reference cell may be determined in conjunction with other criteria (e.g., cell index, SCS, and UL slot ratio). For example, when there are two cells having the longest TDD configuration periodicity, a cell having the lowest SCS between the two cells may be selected as the reference cell.

Up to UL slot part: the cell that includes the largest number of UL slots may be determined as the reference cell. The UE may determine a cell including the maximum number of UL slots during the same time interval among the plurality of cells as a reference cell. Here, the same time interval may be the longest TDD configuration periodicity among the plurality of cells. For example, referring to fig. 49, a cell #1 including the largest number of UL slots may be determined as a reference cell, and the TDW of the cell #1 may be applied to all cells. When there are multiple cells including the maximum number of UL slots, the reference cell may be determined in conjunction with other criteria (e.g., cell index, SCS, and TDD configuration period), and the cell having the longest TDD configuration periodicity between the two cells may be selected as the reference cell.

In the (UL) CA scenario, according to a third example, the UE may determine the TDW based on consecutive time slots among a union of UL time slots of a plurality of (uplink) cells. In order to include as many TDD configurations as possible for the configured plurality of cells in the TDW, the UE may determine the TDW with reference to consecutive slots among units of UL slots among the plurality of cells. Here, the combination of UL slots means slots including UL symbols in at least one cell. For example, referring to fig. 50, assume that the UE has been configured such that different TDD configurations are performed for two cells, respectively, and that the two cells have the same scs=15 kHz. For cell #0 and cell #1, the ue may determine the unit of consecutive UL slots as one TDW. That is, the UE may determine one TDW including the fourth, fifth, ninth, and tenth slots of the cell #0 and the fifth to tenth slots of the cell #1 and apply it to TDWs of all cells.

The methods and systems of the present disclosure are described with respect to particular embodiments, but computer systems having general hardware architectures may be used to implement some or all of the configuration elements, operations of the present disclosure.

The above description of the present disclosure is for illustrative purposes, and those skilled in the art to which the present disclosure pertains will appreciate that modifications of other specific forms can be readily achieved without changing the technical spirit or essential features of the present disclosure. Accordingly, it should be understood that the above-described embodiments are illustrative in all respects, rather than restrictive. For example, each element described as one type may be implemented in a distributed manner, and similarly, elements described as distributed may also be implemented in combination.

The scope of the present disclosure is indicated by the claims to be described below rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present disclosure.

Industrial applicability

The present invention can be applied to a user equipment, a base station or any other device in a wireless communication system.

Claims

1. A User Equipment (UE) for use in a wireless communication system, the UE comprising:

A communication module; and

A processor configured to control the communication module,

Wherein the processor is configured to:

Performing transmission of an uplink channel on a set of time slots; and

A demodulation reference signal (DMRS) is transmitted for transmission of the uplink channel over the set of slots,

Wherein when configuring joint channel estimation operations, the DMRS is transmitted such that phase continuity and power consistency are maintained over a plurality of consecutive time slots within a time window, an

When the length of the time window is not configured by the base station, the time window is determined from smaller values between:

(1) A number of time slots including transmission of the uplink channel; and

(2) A maximum number of time slots in which the UE can maintain the phase continuity and power consistency according to UE capabilities.

2. The UE of claim 1, wherein the DMRS is used for slot-based individual channel estimation when the joint channel estimation operation is not configured.

3. The UE of claim 1, wherein the time window is determined to be configured by the base station when a length of the time window is configured by the base station.

4. The UE of claim 1, wherein the number of time slots including transmission of the uplink channel corresponds to a number of time slots from a time slot in which transmission of the uplink channel begins to a time slot in which transmission of the uplink channel is complete.

5. The UE of claim 1, wherein the number of time slots comprising transmissions of the uplink channel corresponds to a number of consecutive time slots comprising transmissions of the uplink channel.

6. The UE of claim 1, wherein the uplink channel comprises a PUCCH repeated transmission or a PUSCH repeated transmission.

7. The UE of claim 1, wherein the uplink channel comprises a PUSCH retransmission type A, PUSCH retransmission type B, a PUSCH transmission with a Transport Block Size (TBS) determined with reference to multiple slots, or a PUSCH retransmission with a TBS determined with reference to multiple slots.

8. A method for use by a User Equipment (UE) in a wireless communication system, the method comprising:

Performing transmission of an uplink channel on a set of time slots; and

Wherein when configuring joint channel estimation operations, the DMRS is transmitted such that phase continuity and power consistency over a plurality of consecutive time slots within a time window is maintained, an

(1) A number of time slots including transmission of the uplink channel; and

9. The method of claim 8, wherein the DMRS is used for slot-based individual channel estimation when the joint channel estimation operation is not configured.

10. The method of claim 8, wherein the time window is determined to be configured by the base station when a length of the time window is configured by the base station.

11. The method of claim 8, wherein the number of time slots including transmission of the uplink channel corresponds to a number of time slots from a time slot in which transmission of the uplink channel begins to a time slot in which transmission of the uplink channel is complete.

12. The method of claim 8, wherein the number of time slots comprising transmissions of the uplink channel corresponds to a number of consecutive time slots comprising transmissions of the uplink channel.

13. The method of claim 8, wherein the uplink channel comprises a PUCCH repeat transmission or a PUSCH repeat transmission.

14. The method of claim 8, wherein the uplink channel comprises a PUSCH retransmission type A, PUSCH retransmission type B, a PUSCH transmission with a Transport Block Size (TBS) determined with reference to multiple slots, or a PUSCH retransmission with a TBS determined with reference to multiple slots.