Method and apparatus for transmitting signal in wireless communication system

Abstract

The present invention relates to a wireless communication system and, in particular, to a method and a wireless device for a wireless communication system, the method comprising the steps of: receiving a cell-specific RRC signal on a slot format, the slot format comprising information on a type of a symbol; the type of the symbol comprises at least one of a DI symbol, a flexible symbol and an UL symbol; determining whether the RO in the PRACH slot is valid, where the determining includes determining whether the RO is valid based on whether the RO starts from at least Ngap symbols after the last DI symbol; and performing UL transmission or DL reception on the basis of whether the RO is valid.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system. Specifically, the present disclosure relates to a method of transmitting a signal in a wireless communication system and an apparatus using the method. Background Art

[0002] After the commercialization of the fourth generation (4G) communication system, in order to meet the increasing demand for wireless data services, efforts are being made to develop a new fifth generation (5G) communication system. The 5G communication system is referred to as a super 4G network communication system, a post-LTE system, or a new radio (NR) system. To achieve a high data transmission rate, the 5G communication system includes a system operating using millimeter wave (mmWave) bands of 6 GHz or higher, and includes a communication system operating using bands of 6 GHz or lower in terms of ensuring coverage, such that implementation in base stations and terminals is under consideration.

[0003] The third generation partnership project (3GPP) NR system improves the spectral efficiency of the network and enables communication providers to provide more data and voice services on a given bandwidth. Therefore, the 3GPP NR system is designed to meet the demand for high-speed data and media transmission in addition to supporting a large amount of voice. The advantages of the NR system 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 an enhanced end-user environment and a simple architecture.

[0004] For more efficient data processing, the dynamic TDD of the NR system can use a method for changing the number of orthogonal frequency division multiplexing (OFDM) symbols that can be used in the uplink and downlink according to the data traffic direction of cell users. For example, when the downlink traffic of a cell is more than the uplink traffic, the base station can allocate multiple downlink OFDM symbols to a time slot (or subframe). Information on the time slot configuration should be sent to the terminal.

[0005] In order to mitigate the path loss of radio waves and increase the transmission distance of radio waves in the mmWave band, in the 5G communication system, beamforming, massive multiple-input / multiple-output (massive MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, hybrid beamforming that combines analog beamforming and digital beamforming, and massive antenna technology have been discussed. In addition, for the network improvement of the system, in the 5G communication system, technology development related to evolved small cells, advanced small cells, cloud radio access network (cloud RAN), ultra-dense network, device-to-device communication (D2D), vehicle-to-everything communication (V2X), wireless backhaul, non-terrestrial network communication (NTN), mobile network, cooperative communication, coordinated multi-point (CoMP), interference cancellation, etc. is underway. In addition, in the 5G system, hybrid FSK and QAM modulation (FQAM) and sliding window superimposed 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 technologies are being developed.

[0006] Meanwhile, in the human-centered connected network where humans generate and consume information, the Internet has evolved into the Internet of Things (IoT) network, which exchanges information between distributed components such as objects. The Internet of Everything (IoE) technology that combines IoT technology and big data processing technology through connection to a cloud server is also emerging. To implement the IoT, technical elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology are required, so in recent years, technologies such as sensor networks, machine-to-machine (M2M), and machine type communication (MTC) have been studied to connect between objects. In the IoT environment, intelligent Internet technology (IT) services can be provided, which collect and analyze data generated from the connected objects to create new value in human life. Through the integration and hybridization of existing information technology (IT) and various industries, the IoT can be applied to fields such as smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart home appliances, and advanced medical services.

[0007] Therefore, various attempts have been made to apply the 5G communication system to the IoT network. For example, technologies such as sensor networks, machine-to-machine (M2M), and machine type communication (MTC) are realized through technologies such as beamforming, MIMO, and array antennas. The application of cloud RAN as the above big data processing technology is an example of the integration of 5G technology and IoT technology. Generally, mobile communication systems are developed to provide voice services while ensuring the activities of users.

[0008] However, mobile communication systems are not only gradually expanding voice services but also data services, and have now evolved to the point of providing high-speed data services. However, in the current mobile communication systems that are providing services, due to resource shortage phenomena and users' high-speed service demands, a more advanced mobile communication system is needed. SUMMARY OF THE INVENTION

[0009] TECHNICAL PROBLEM

[0010] Aspects of the present disclosure are to provide a method for efficiently transmitting signals in a wireless communication system and an apparatus using the method. Specifically, aspects of the present disclosure are to provide a method for determining a valid RO in a wireless communication system and an apparatus using the method. In addition, aspects of the present disclosure are to provide a method for transmitting and receiving signals based on a valid RO and an apparatus using the method.

[0011] TECHNICAL SOLUTION

[0012] An aspect of the present disclosure provides a UE used 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: receive a cell-specific (cell-common) radio resource control (RRC) signal regarding a slot format, the slot format including information about the type of symbols, and the type of symbols including at least one of a downlink (DL) symbol, a flexible symbol, and an uplink (UL) symbol; determine whether a random access channel (RO) in a physical random access channel (PRACH) slot is valid, the determination including determining whether the RO is valid based on whether the RO starts at least N gap symbols after the last DL symbol; and perform UL transmission or DL reception based on whether the RO is valid, wherein in at least one slot, a plurality of subbands are configured within a frequency band, the plurality of subbands including DL subbands and UL subbands, and in a case where the RO exists in a UL subband, based on the DL symbols configured by the cell-specific RRC signal, excluding the symbols in which the UL subband is configured, to determine the last DL symbol.

[0013] In another aspect of the present disclosure, a method used by a UE in a wireless communication system may include: receiving a cell-specific (cell-common) radio resource control (RRC) signal regarding a slot format, the slot format including information about the type of symbols, and the type of symbols including at least one of a downlink (DL) symbol, a flexible symbol, and an uplink (UL) symbol; determining whether a random access channel (RO) in a physical random access channel (PRACH) slot is valid, the determination including determining whether the RO is valid based on whether the RO starts at least N gapA symbol is used to determine whether the RO is valid; and UL transmission or DL reception is performed based on whether the RO is valid. Among them, in at least one time slot, multiple sub-bands are configured within a frequency band, and the multiple sub-bands include DL sub-bands and UL sub-bands. And when the RO exists in the UL sub-band, the last DL symbol is determined by excluding the symbol in which the UL sub-band is configured based on the DL symbol configured by the cell-specific RRC signal.

[0014] Preferably, the cell-specific RRC signal may include common time-division duplex (TDD) UL-DL configuration information.

[0015] Preferably, the determination may include that when the RO is within the UL sub-band and the RO does not precede the synchronization signal / physical broadcast channel (SS / PBCH) block within the PRACH time slot and starts at least N gap symbols after the last DL symbol, and starts at least N gap symbols after the last symbol of the SS / PBCH block reception, it is determined that the RO is valid.

[0016] Preferably, the determination may include that when the RO exists on the UL symbol set configured by the cell-specific RRC signal, it is determined that the RO is valid.

[0017] Preferably, N can be determined based on the subcarrier spacing (SCS) of the PRACH as follows gap : When the SCS of the PRACH is 1.25 kHz or 5 kHz, N gap = 0; and when the SCS of the PRACH is 15 kHz, 30 kHz, 60 kHz or 120 kHz, N gap = 2.

[0018] Preferably, when the RO is valid, the PRACH can be transmitted in the RO.

[0019] Preferably, in the case where (a) the RO exists on the UL sub-band, (b) the RO is valid, and (c) the physical downlink shared channel (PDSCH) scheduled for the UE overlaps with at least one of N gap symbols and the RO in the time domain, it is determined whether to receive the PDSCH based on whether the PDSCH has been scheduled by downlink control information (DCI) or a higher layer (e.g., RRC). Here, the resources overlapping in the time domain may include at least one symbol.

[0020] Preferably, in the case where (a) the RO exists on the UL sub-band, (b) the RO is valid, (c) the physical downlink shared channel (PDSCH) scheduled for the UE overlaps with N gapAt least one of the symbols and the RO overlap, and (d) when the PDSCH is scheduled by DCI, the PDSCH can be received normally, and PRACH transmission in the RO is not allowed.

[0021] Preferably, in the case where (a) the RO is present on the UL sub-band, (b) the RO is valid, (c) the PDSCH scheduled for the UE overlaps with at least one of the N gap symbols and the RO, and (d) when the PDSCH is scheduled by a higher layer (e.g., RRC), the PDSCH can perform rate matching and reception based on the overlapping resources in the time domain, and PRACH transmission in the RO is allowed. Here, the overlapping resources in the time domain may include at least one symbol. In addition, the PDSCH scheduled by the higher layer may include a semi-static persistent scheduling (SPS) PDSCH.

[0022] Advantageous Effects of the Invention

[0023] The present disclosure provides a method for efficiently transmitting signals in a wireless communication system and an apparatus using the method. In addition, the present disclosure provides a method for determining a valid RO in a wireless communication system and an apparatus using the method. In addition, the present disclosure provides a method for transmitting and receiving signals based on a valid RO and an apparatus using the method.

[0024] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and those skilled in the art to which the present disclosure pertains will clearly understand other effects not mentioned from the following description. Brief Description of the Drawings

[0025] Figure 1 Illustrates an example of a radio frame structure used in a wireless communication system.

[0026] Figure 2 Illustrates an example of a downlink (DL) / uplink (UL) time slot structure in a wireless communication system.

[0027] Figure 3 Is a diagram for explaining physical channels used in a 3GPP system and a typical signal transmission method using the physical channels.

[0028] Figure 4a and Figure 4b Illustrates an SS / PBCH block for initial cell access in a 3GPP NR system.

[0029] Figure 5a and Figure 5b Illustrates a process for transmitting control information and control channels in a 3GPP NR system.

[0030] Figure 6Illustrates a control resource set (CORESET) in a 3GPP NR system where a physical downlink control channel (PDCCH) can be transmitted.

[0031] Figure 7 Illustrates a method for configuring a PDCCH search space in a 3GPP NR system.

[0032] Figure 8 Is a conceptual diagram illustrating carrier aggregation.

[0033] Figure 9 Is a diagram for explaining single - carrier communication and multi - carrier communication.

[0034] Figure 10 Is a diagram showing an example where cross - carrier scheduling technology is applied.

[0035] Figure 11 Is a block diagram showing the configurations of a UE and a base station according to an embodiment of the present disclosure.

[0036] Figures 12 to 13 Illustrates a sub - band configuration method.

[0037] Figure 14 Illustrates a random access channel occasion (RO) in a time slot.

[0038] Figures 15 to 19 Illustrates a method for determining a valid RO according to an example of the present disclosure.

[0039] Figures 20 to 23 Illustrates signal transmission and reception according to an example of the present disclosure. Detailed Description

[0040] The terms used in the specification adopt as much as possible the currently widely used general terms in consideration of the functions in the present invention, but these terms can be changed according to the intentions, habits of those skilled in the art, and the emergence of new technologies. Additionally, in specific cases, there are terms arbitrarily selected by the applicant, and in such cases, their meanings will be described in the corresponding description part of the present invention. Therefore, it is intended that the terms used in the specification should not be analyzed only based on the name of the term, but should be analyzed based on the substantial meanings of the terms and the content throughout the specification.

[0041] Throughout the specification and the following claims, when an element is described as "connected" to another element, the element can be "directly connected" to the other element or "electrically connected" to the other element through a third element. Additionally, unless explicitly stated to the contrary, the word "comprising" will be understood to imply the inclusion of the stated elements, without implying 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 specific threshold can be appropriately replaced with "greater than" or "less than", respectively.

[0042] The following techniques can 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), etc. CDMA can be implemented by wireless technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can 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 can be implemented by wireless technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA), etc. UTRA is part of the Universal Mobile Telecommunications System (UMTS). The 3rd Generation Partnership Project (3GPP) Long-Term Evolution (LTE) is part of the Evolved UMTS (E-UMTS) that uses Evolved UMTS Terrestrial Radio Access (E-UTRA), and LTE-Advanced (A) is an evolved version of 3GPP LTE. 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-latency communication (URLLC), and massive machine-type communication (mMTC) services that are requirements for IMT-2020. For the sake of clear description, 3GPP NR is mainly described, but the technical idea of the present invention is not limited thereto.

[0043] Unless otherwise specified in this specification, a base station may refer to a next-generation Node B (gNB) as defined in 3GPP NR. Additionally, unless otherwise stated, a terminal may refer to a User Equipment (UE). Hereinafter, for the sake of facilitating the understanding of the description, each content is separately divided into embodiments and described, but each of the embodiments can be used in combination with each other. In the present disclosure, the configuration of the UE may be indicated by the configuration of the base station. Specifically, the base station may send a channel or a signal to the UE to configure the operation of the UE or the parameter values used in the wireless communication system.

[0044] Figure 1Illustrate an example of a radio frame structure used in a wireless communication system.

[0045] Reference Figure 1 , the radio frame (or radio frame) used in the 3GPP NR system may have a length of 10 ms (Δf max N f / 100)*T c ). In addition, the radio frame includes 10 subframes (SFs) of equal size. Here, Δf max = 480*10 3 Hz, N f = 4096, T c = 1 / (Δf ref *N f,ref ), Δf ref = 15*10 3 Hz, and N f,ref = 2048. Numbers from 0 to 9 can be assigned to the 10 subframes within a radio frame respectively. The length of each subframe is 1 ms and it may include one or more time slots according to the subcarrier spacing. More specifically, in the 3GPP NR system, the subcarrier spacing that can be used is 15*2 μ kHz, and μ can have values of μ = 0 to 4 as subcarrier spacing configurations. That is, 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz can be used for the subcarrier spacing. A subframe with a length of 1 ms may include 2 μ time slots. In this case, the length of each time slot is 2 -μ ms. Numbers from 0 to 2 μ -1 can be assigned to the 2 μ time slots within a subframe respectively. In addition, numbers from 0 to 10*2 μ -1 can be assigned to the time slots within a radio frame respectively. Time resources can be distinguished by at least one of the radio frame number (also called radio frame index), subframe number (also called subframe index), and time slot number (or time slot index).

[0046] Figure 2 Illustrate an example of the downlink (DL) / uplink (UL) time slot structure in a wireless communication system. In particular, Figure 2 show the structure of the resource grid of the 3GPP NR system.

[0047] There is one resource grid for each antenna port. Reference Figure 2, a time slot includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols in the time domain and a plurality of resource blocks (RBs) in the frequency domain. One OFDM symbol also refers to a symbol interval. Unless otherwise specified, the OFDM symbol can be abbreviated as a symbol. One RB includes 12 consecutive subcarriers in the frequency domain. Refer to Figure 2 , the signal transmitted from each time slot can be represented by a resource grid including N size,μ grid,x *N RB sc subcarriers and N slot symb OFDM symbols. Here, when the signal is a DL signal, x = DL, and when the signal is a UL signal, x = UL. N size,μ grid,x represents the number of resource blocks (RBs) according to the subcarrier spacing component μ (x is DL or UL), and N slot symb represents the number of OFDM symbols in a time slot. N RB sc is the number of subcarriers that make up one RB and N RB sc = 12. The OFDM symbol can be referred to as a cyclic prefix OFDM (CP-OFDM) symbol or a discrete Fourier transform spread OFDM (DFT-s-OFDM) symbol according to the multiple access scheme.

[0048] The number of OFDM symbols included in a time slot can vary according to the length of the cyclic prefix (CP). For example, in the case of a normal CP, a time slot includes 14 OFDM symbols, but in the case of an extended CP, a time slot can include 12 OFDM symbols. In a specific embodiment, the extended CP can only be used at a 60 kHz subcarrier spacing. In Figure 2 , for the convenience of description, as an example, a time slot is configured with 14 OFDM symbols, but the embodiments of the present disclosure can be applied to time slots with different numbers of OFDM symbols in a similar manner. Refer to Figure 2 , each OFDM symbol includes N size,μ grid,x *N RB sc subcarriers in the frequency domain. The type of subcarriers can be divided into data subcarriers for data transmission, reference signal subcarriers for the transmission of reference signals, and guard bands. The carrier frequency is also referred to as the center frequency (fc).

[0049] One RB can be composed of N RB sc(e.g., 12) consecutive subcarrier definitions. For reference, a resource configured with one OFDM symbol and one subcarrier may be referred to as a resource element (RE) or a tone. Thus, an 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 a time slot. k can be an index assigned from 0 to N size,μ grid,x *N RB sc – 1 in the frequency domain, and l can be an index assigned from 0 to N slot symb – 1 in the time domain.

[0050] For the UE to receive signals from or send signals to the base station, the time / frequency of the UE can 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 the time and frequency parameters necessary to demodulate DL signals and transmit UL signals at the correct time.

[0051] Each symbol of a radio frame used in time division duplex (TDD) or unpaired spectrum can be configured with at least one of a DL symbol, a UL symbol, and a flexible symbol. A radio frame used as a DL carrier in frequency division duplex (FDD) or paired spectrum can be configured with a DL symbol or a flexible symbol, while a radio frame used as a UL carrier can be configured with a UL symbol or a flexible symbol. In a DL symbol, DL transmission is possible, but UL transmission is not. In a UL symbol, UL transmission is possible, but DL transmission is not. A flexible symbol can be determined to be used as DL or UL according to the signal.

[0052] Information about the type of each symbol, i.e., information indicating any one of a DL symbol, a UL symbol, and a flexible symbol, can be configured with a cell-specific or common radio resource control (RRC) signal. Additionally, information about the type of each symbol can be configured with a UE-specific or dedicated RRC signal. The base station notifies, by using the cell-specific RRC signal, i) the period of the cell-specific time slot configuration, ii) the number of time slots having only DL symbols starting from the beginning of the period of the cell-specific time slot configuration, iii) the number of DL symbols starting from the first symbol of the time slot immediately following the time slot having only DL symbols, iv) the number of time slots having only UL symbols starting from the end of the period of the cell-specific time slot configuration, and v) the number of UL symbols starting from the last symbol of the time slot immediately preceding the time slot having only UL symbols. Here, a symbol not configured with any of a UL symbol and a DL symbol is a flexible symbol.

[0053] When the information on the symbol type is configured with UE-specific RRC signaling, the base station can signal whether the flexible symbol is a DL symbol or a UL symbol with cell-specific RRC signaling. In this case, the UE-specific RRC signaling cannot change the DL symbol or UL symbol configured with the cell-specific RRC signaling to another symbol type. The UE-specific RRC signaling can signal the number of DL symbols among the N symbols of the corresponding time slot and the number of UL symbols among the N symbols of the corresponding time slot for each time slot. In this case, the DL symbols of the time slot can be continuously configured as the first symbol to the i-th symbol of the time slot. In addition, the UL symbols of the time slot can be continuously configured as the j-th symbol to the last symbol of the time slot (where i < j). In a time slot, the symbol that is not configured with any of the UL symbols and DL symbols is a flexible symbol. slot symb The number of DL symbols among the N symbols and the number of UL symbols among the N symbols slot symb In this case, the DL symbols of the time slot can be continuously configured as the first symbol to the i-th symbol of the time slot. In addition, the UL symbols of the time slot can be continuously configured as the j-th symbol to the last symbol of the time slot (where i < j). In a time slot, the symbol that is not configured with any of the UL symbols and DL symbols is a flexible symbol.

[0054] Figure 3 is a diagram for explaining the physical channels used in a 3GPP system (e.g., NR) and a typical signal transmission method using the physical channels.

[0055] If the power of the UE is turned on or the UE camps on a new cell, the UE performs initial cell search (S101). Specifically, the UE can synchronize with the BS in the initial cell search. To this end, the UE can receive the primary synchronization signal (PSS) and the secondary synchronization signal (SSS) from the base station to synchronize with the base station and obtain information such as the cell ID. Thereafter, the UE is able to receive the physical broadcast channel from the base station and obtain the broadcast information in the cell.

[0056] After the initial cell search is completed, the UE receives the physical downlink shared channel (PDSCH) according to the physical downlink control channel (PDCCH) and the 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 the cell common system information in radio resource control (RRC) for the UE to operate properly at the physical layer, and is referred to as the remaining system information (RSMI) or system information block (SIB) 1.

[0057] When the UE initially accesses the base station or does not have radio resources for signal transmission (when the UE is in the RRC_IDLE mode), the UE can perform a random access procedure (operations S103 to S106) on the base station. First, the UE can send a preamble (S103) through the Physical Random Access Channel (PRACH) and receive a response message for the preamble from the base station through the PDCCH and the corresponding PDSCH (S104). When the UE receives a valid random access response message, the UE sends data including the UE's identifier, etc. to the base station through the Physical Uplink Shared Channel (PUSCH) indicated by the UL grant sent from the base station via the PDCCH (S105). Next, the UE waits for the reception of the PDCCH as an indication from the base station for conflict resolution. If the UE successfully receives the PDCCH (S106) through the UE's identifier, the random access procedure is terminated. During the random access procedure, the UE can obtain UE-specific system information necessary for the UE to operate properly at the physical layer in the RRC layer. When the UE obtains the UE-specific system information from the RRC layer, the UE enters the RRC_CONNECTED mode.

[0058] The RRC layer is used for message generation and management to perform control between the UE and the Radio Access Network (RAN). More specifically, in the RRC layer, the base station and the UE can perform broadcast of cell system information, delivery management of paging messages, mobility management and handover, measurement report and its control, UE capability management, and storage management including the existing management necessary for all UEs in the cell. Generally, since the update of the signal sent from the RRC layer (hereinafter referred to as the RRC signal) is longer than the transmission / reception cycle (i.e., Transmission Time Interval, TTI) in the physical layer, the RRC signal can remain unchanged for a long time.

[0059] After the above process, the UE receives the PDCCH / PDSCH (S107) and sends the Physical Uplink Shared Channel (PUSCH) / Physical Uplink Control Channel (PUCCH) (S108) as a general UL / DL signal transmission process. In particular, the UE can receive Downlink Control Information (DCI) through the PDCCH. The DCI can include control information such as resource allocation information for the UE. In addition, the format of the DCI can vary according to a predetermined use. The Uplink Control Information (UCI) sent by the UE to the base station through the UL includes DL / UL ACK / NACK signals, Channel Quality Indicator (CQI), Precoding Matrix Index (PMI), Rank Indicator (RI), etc. Here, the CQI, PMI, and RI can be included in the Channel State Information (CSI). In the 3GPP NR system, the UE can send control information such as the above-mentioned HARQ-ACK and CSI through the PUSCH and / or PUCCH.

[0060] Figure 4a and Figure 4b The figure shows an SS / PBCH block for initial cell access in a 3GPP NR system.

[0061] When the power is turned on or when the UE wants to access a new cell, the UE can obtain time and frequency synchronization with the cell and perform an initial cell search process. The UE can detect the physical cell identity N of the cell during the cell search process. cell ID To this end, the UE can receive synchronization signals, such as the primary synchronization signal (PSS) and the secondary synchronization signal (SSS), from the base station and synchronize with the base station. In this case, the UE can obtain information such as the cell identity (ID).

[0062] Reference Figure 4a , the synchronization signal (SS) will be described in more detail. The synchronization signal can be classified into PSS and SSS. The PSS can be used to obtain time-domain synchronization and / or frequency-domain synchronization, such as OFDM symbol synchronization and slot synchronization. The SSS can be used to obtain frame synchronization and cell group ID. Referring to Figure 4a and Table 1, the SS / PBCH block can be configured with 20 consecutive RBs (= 240 subcarriers) on the frequency axis and can be configured with 4 consecutive OFDM symbols on the time axis. In this case, in the SS / PBCH block, the PSS is transmitted in the first OFDM symbol and the SSS is transmitted in the third OFDM symbol through the 56th to 182nd subcarriers. Here, the lowest subcarrier index of the SS / PBCH block is numbered from 0. In the first OFDM symbol where the PSS is transmitted, the base station does not transmit signals through the remaining subcarriers, i.e., the 0th to 55th subcarriers and the 183rd to 239th subcarriers. In addition, in the third OFDM symbol where the SSS is transmitted, the base station does not transmit signals through the 48th to 55th subcarriers and the 183rd to 191st subcarriers. The base station transmits the physical broadcast channel (PBCH) through the remaining REs in the SS / PBCH block other than the above signals.

[0063] [Table 1]

[0064]

[0065] The SS allows a total of 1008 unique physical layer cell IDs to be grouped into 336 physical layer cell identifier groups through the combination of three PSSs and SSSs, with each group including three unique identifiers. Specifically, such that each physical layer cell ID will be only part of one physical layer cell identifier group. Therefore, the physical layer cell ID N cell ID = 3N (1) ID+N (2) ID Can be uniquely defined by an index N indicating a range of physical layer cell identifier groups from 0 to 335 (1) ID and an index N indicating a range of physical layer identifiers in the physical layer cell identifier group from 0 to 2 (2) ID The UE can detect the PSS and identify one of three unique physical layer identifiers. In addition, 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 the PSS is as follows.

[0066] d PSS (n) = 1 - 2x(m)

[0067]

[0068] 0 ≤ n < 127

[0069] where x(i + 7) = (x(i + 4) + x(i)) mod 2, and is given as

[0070] [x(6) x(5) x(4) x(3) x(2) x(1) x(0)][1 1 1 0 1 1 0].

[0071] In addition, the sequence d SSS (n) of the SSS is as follows.

[0072] d SSS (n) = [1 - 2x 0 ((n + 0 ) mod 127)][1 - 2x 1 ((n + m 1 ) mod 127)]

[0073]

[0074] 0 ≤ n < 127

[0075] where and is given as

[0076] [x 0 (6) x 0 (5) x 0 (4) x 0 (3) x 0 (2) x 0 (1) x 0 (0)] = [0 0 0 0 0 0 1]

[0077] [x 1 (6) x 1 (5) x 1 (4) x 1 (3) x 1 (2) x 1 (1) x 1 (0)] = [0 0 0 0 0 0 1]

[0078] A radio frame with a length of 10 ms can be divided into two half - frames with a length of 5 ms. Refer to Figure 4b , the time slots for transmitting SS / PBCH blocks in each half - frame will be described. The time slot for transmitting the SS / PBCH block can be any one of cases A, B, C, D, and E. In case A, the sub - carrier spacing is 15 kHz and the starting time point of the SS / PBCH block is the ({2,8}+14*n) - th symbol. In this case, at a carrier frequency of 3 GHz or lower, n = 0 or 1. Additionally, at a carrier frequency higher than 3 GHz and lower than 6 GHz, n can be 0, 1, 2, 3. In case B, the sub - carrier spacing is 30 kHz and the starting time point of the SS / PBCH block is {4,8,16,20}+28*n. In this case, at a carrier frequency of 3 GHz or lower, n = 0. Additionally, at a carrier frequency higher than 3 GHz and lower than 6 GHz, n can be 0, 1. In case C, the sub - carrier spacing is 30 kHz and the starting time point of the SS / PBCH block is the ({2,8}+14*n) - th symbol. In this case, at a carrier frequency of 3 GHz or lower, n = 0 or 1. Additionally, at a carrier frequency higher than 3 GHz and lower than 6 GHz, n can be 0, 1, 2, 3. In case D, the sub - carrier spacing is 120 kHz and the starting time point of the SS / PBCH block is the ({4,8,16,20}+28*n) - th symbol. In this case, at a carrier frequency of 6 GHz or higher, n = 0, 1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18. In case E, the sub - carrier spacing is 240 kHz and the starting time point of the SS / PBCH block is the ({8,12,16,20,32,36,40,44}+56*n) - th symbol. In this case, at a carrier frequency of 6 GHz or higher, n = 0, 1, 2, 3, 5, 6, 7, 8.

[0079] Figure 5a and Figure 5b illustrates the process of transmitting control information and control channels in the 3GPP NR system. Refer to Figure 5a, the base station may add a cyclic redundancy check (CRC) masked (e.g., by 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 / target of each control information. The common RNTIs used by one or more UEs may 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). In addition, the UE-specific RNTIs may include at least one of a cell temporary RNTI (C-RNTI) and a CS-RNTI. Thereafter, the base station may perform rate matching (S206) according to the amount of resources used for PDCCH transmission after performing channel coding (e.g., polar coding) (S204). Thereafter, the base station may multiplex DCI based on a PDCCH structure based on control channel elements (CCEs) (S208). In addition, the base station may apply additional processes 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 the basic resource unit for the PDCCH, and one CCE may include multiple (e.g., 6) resource element groups (REGs). One REG may be configured with multiple (e.g., 12) resource elements (REs). The number of CCEs used for one PDCCH may be defined as the aggregation level. In the 3GPP NR system, aggregation levels of 1, 2, 4, 8, or 16 may be used. Figure 5b is a diagram related to the CCE aggregation level and the multiplexing of the PDCCH, and illustrates the type of the CCE aggregation level for one PDCCH and the CCEs transmitted in the control region accordingly.

[0080] Figure 6 Illustrates a control resource set (CORESET) in which a physical downlink control channel (PDCCH) can be transmitted in the 3GPP NR system.

[0081] A CORESET is a time-frequency resource in which PDCCH (i.e., control signals for UEs) is transmitted. Additionally, a search space to be described later can be mapped to a CORESET. Thus, a UE can monitor the time-frequency domain designated as a CORESET instead of monitoring all frequency bands for PDCCH reception, and decode the PDCCH mapped to the CORESET. A base station can configure one or more CORESETs for each cell for a UE. A CORESET can be configured with up to three consecutive symbols on the time axis. Additionally, a CORESET can be configured in units of six consecutive PRBs on the frequency axis. In the embodiment of FIG. 5, CORESET#1 is configured with consecutive PRBs, while CORESET#2 and CORESET#3 are configured with non-consecutive PRBs. A CORESET can be located in any symbol of a time slot. For example, in the embodiment of FIG. 5, CORESET#1 starts from the first symbol of the time slot, CORESET#2 starts from the fifth symbol of the time slot, and CORESET#9 starts from the ninth symbol of the time slot.

[0082] Figure 7 FIG. illustrates a method for setting a PUCCH search space in a 3GPP NR system.

[0083] To transmit PDCCH to a UE, each CORESET can have at least one search space. In an embodiment of the present disclosure, a search space is a set of all time-frequency resources (hereinafter, PDCCH candidates) that can be used to transmit PDCCH for a UE. A search space can include a common search space that requires UEs of 3GPP NR to search jointly and a UE-specific search space or UE-specific search space that requires a specific UE to search. In the common search space, a UE can monitor PDCCH that is set such that all UEs in cells belonging to the same base station search jointly. Additionally, a UE-specific search space can be set for each UE such that the UE monitors PDCCH allocated to each UE at search space positions that differ according to the UE. In the case of a UE-specific search space, since there is a limited control region where PDCCH can be allocated, the search spaces between UEs can partially overlap and be allocated. Monitoring PDCCH includes blindly decoding PDCCH candidates in a search space. When the blind decoding is successful, it can be expressed as (successfully) detecting / receiving PDCCH, while when the blind decoding fails, it can be expressed as not detecting / not receiving or not successfully detecting / receiving PDCCH.

[0084] For ease of explanation, a physical downlink control channel (PDCCH) that is scrambled with a group common (GC) RNTI known to one or more UEs in advance to send downlink control information to one or more UEs is referred to as a group common (GC) PDCCH or a common PDCCH. In addition, a PDCCH that is scrambled with an RNTI of a specific terminal known to a specific UE to send uplink scheduling information or downlink scheduling information to the specific UE is referred to as a UE-specific PDCCH. The common PDCCH can be included in a common search space, and the UE-specific PDCCH can be included in the common search space or the UE-specific search space.

[0085] The base station can signal to each UE or UE group via the PDCCH information regarding resource allocation related to the paging channel (PCH) and the downlink shared channel (DL-SCH) as transmission channels (i.e., DL grant) or information regarding resource allocation related to the uplink shared channel (UL-SCH) and hybrid automatic repeat request (HARQ) (i.e., UL grant). The base station can send the PCH transport block and the DL-SCH transport block via the PDSCH. The base station can send data excluding specific control information or specific service data via the PDSCH. In addition, the UE can receive data excluding specific control information or specific service data via the PDSCH.

[0086] The base station can include in the PDCCH information on which UE(s) the PDSCH data is to be sent to and how the PDSCH data is to be received and decoded by the corresponding UE, and send the PDCCH. For example, assume that the DCI transmitted on a specific PDCCH is CRC masked with an RNTI "A", and the DCI indicates that the PDSCH is allocated to radio resource "B" (e.g., frequency location) and indicates transmission format information "C" (e.g., transport block size, modulation scheme, coding information, etc.). The UE monitors the PDCCH using the RNTI information the UE has. In this case, if there is a UE that performs blind decoding of the PDCCH using the "A" RNTI, the UE receives the PDCCH and receives the PDSCH indicated by "B" and "C" based on the information of the received PDCCH.

[0087] Table 2 shows an embodiment of a physical uplink control channel (PUCCH) used in a wireless communication system.

[0088] [Table 2]

[0089] 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

[0090] The PUCCH can be used to send the following uplink control information (UCI).

[0091] - Scheduling Request (SR): Information used to request UL UL-SCH resources.

[0092] - HARQ-ACK: Response to PDCCH (indicating DL SPS release) and / or response to DL transport block (TB) on PDSCH. HARQ-ACK indicates whether the information sent on PDCCH or PDSCH is received. HARQ-ACK responses include positive ACK (simply referred to as ACK), negative ACK (NACK hereinafter), discontinuous transmission (DTX), or NACK / DTX. Here, the term HARQ-ACK is used interchangeably with HARQ-ACK / NACK and ACK / NACK. Generally, ACK can be represented by bit value 1, while NACK can be represented by bit value 0.

[0093] - Channel State Information (CSI): Feedback information about DL channels. The UE generates it based on CSI-reference signal (RS) sent by the base station. Feedback information related to multiple-input multiple-output (MIMO) includes rank indicator (RI) and precoding matrix indicator (PMI). CSI can be divided into CSI part 1 and CSI part 2 according to the information indicated by CSI.

[0094] In the 3GPP NR system, five PUCCH formats can be used to support various service scenarios, various channel environments, and frame structures.

[0095] PUCCH format 0 is a format capable of sending 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 0 can be sent through one or two OFDM symbols on the time axis and one PRB on the frequency axis. When PUCCH format 0 is sent in two OFDM symbols, the same sequence on the two symbols can be sent through different RBs. In this case, the sequence can be a cyclic shift (CS) sequence from the base sequence for PUCCH format 0. Through this, the UE can obtain frequency diversity gain. Specifically, the UE can determine the cyclic shift (CS) value m bit bit UCI (M bit = 1 or 2). In addition, the sequence obtained by cyclic shifting the base sequence of length 12 based on the predetermined CS value m cs . can be mapped to 1 OFDM symbol and 12 REs of 1 RB and sent. When the number of cyclic shifts available to the UE is 12 and M cs = 1, 1-bit UCI 0 and 1 can be mapped to two cyclic shift sequences with a difference in cyclic shift values of 6 respectively. In addition, when M bit = 1 bitWhen = 2, the 2-bit UCI 00, 01, 11, and 10 can be mapped to four cyclic shift sequences with a difference of 3 in their cyclic shift values respectively.

[0096] PUCCH format 1 can deliver 1-bit or 2-bit HARQ-ACK information or SR. PUCCH format 1 can 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 can be one of 4 to 14. More specifically, the UCI with M bit = 1 can be modulated by BPSK. The UE can modulate the UCI with M bit = 2 by 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 can be the basic sequence for PUCCH format 0. The UE extends the even-numbered OFDM symbols assigned to PUCCH format 1 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 the OCC to be used. The Demodulation Reference Signal (DMRS) can be extended by the OCC and mapped to the odd-numbered OFDM symbols of PUCCH format 1.

[0097] PUCCH format 2 can deliver UCI of more than 2 bits. PUCCH format 2 can 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, the sequences transmitted in different RBs through the two OFDM symbols can be the same. Here, the sequence can be a plurality of modulated complex-valued symbols d(0),..., d(M symbol -1). Here, M symbol can be M bit / 2. Through this, the UE can obtain a frequency diversity gain. More specifically, the M bit -bit UCI (M bit > 2) is bit-level scrambled, QPSK modulated, and mapped to the RBs of one or two OFDM symbols. Here, the number of RBs can be one of 1 to 16.

[0098] PUCCH format 3 or PUCCH format 4 can deliver UCI of more than 2 bits. PUCCH format 3 or PUCCH format 4 can 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 can be one of 4 to 14. Specifically, the UE uses e / 2-binary phase shift keying (BPSK) or QPSK to modulate the M bit -bit UCI (M bit >2) to generate complex-valued symbols d(0) to d(M symb -1). Here, when using π / 2-BPSK, M symb = M bit , and when using QPSK, M symb = M bit / 2. The UE may not apply block unit extension to PUCCH format 3. However, the UE may use a PreDFT-OCC of length 12 to apply block unit extension to one RB (i.e., 12 subcarriers) so that PUCCH format 4 can have two or four multiplexing capabilities. The UE performs transmit precoding (or DFT precoding) on the extended signal and maps it to each RE to transmit the extended signal.

[0099] In this case, the number of RBs occupied by PUCCH format 2, PUCCH format 3, or PUCCH format 4 can be determined according to the length and maximum coding rate of the UCI transmitted by the UE. When the UE uses PUCCH format 2, the UE can 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 PUCCH format 2, PUCCH format 3, or PUCCH format 4 can use, the UE can, according to the priority of the UCI information, only transmit the remaining UCI information without transmitting some UCI information.

[0100] PUCCH format 1, PUCCH format 3, or PUCCH format 4 can be configured by an RRC signal to indicate frequency hopping in a time slot. When frequency hopping is configured, the index of the RB to be frequency-hopped can be configured by an RRC signal. When PUCCH format 1, PUCCH format 3, or PUCCH format 4 is transmitted through N OFDM symbols on the time axis, the first hop can have floor(N / 2) OFDM symbols and the second hop can have ceiling(N / 2) OFDM symbols.

[0101] PUCCH format 1, PUCCH format 3, or PUCCH format 4 can be configured to be repetitively transmitted in multiple time slots. In this case, the number K of time slots for repetitively transmitting the PUCCH can be configured by an RRC signal. The repetitively transmitted PUCCH must start from an OFDM symbol at a constant position in each time slot and have a constant length. When one of the OFDM symbols among the OFDM symbols of the time slot in which the UE is supposed to transmit the PUCCH is indicated as a DL symbol by an RRC signal, the UE may not transmit the PUCCH in the corresponding time slot and delay the transmission of the PUCCH to the next time slot to transmit the PUCCH.

[0102] Meanwhile, in the 3GPP NR system, the UE can perform transmission / reception using a bandwidth less than or equal to the bandwidth of a carrier (or cell). For this, the UE can be configured with a bandwidth part (BWP) composed of a continuous bandwidth of a part of the bandwidth of the carrier. A UE operating according to TDD operation or in an unpaired spectrum can receive up to four DL / UL BWP pairs for one carrier (or cell). In addition, the UE can activate one DL / UL BWP pair. A UE operating according to FDD operation or in a paired spectrum can receive up to 4 DL BWPs on a downlink carrier (or cell) and up to 4 UL BWPs on an uplink carrier (or cell). For each carrier (or cell), the UE can activate one DL BWP and one UL BWP. The UE may not receive or transmit in time-frequency resources other than the activated BWP. The activated BWP can be referred to as the active BWP.

[0103] The base station can indicate the activated BWP among the BWPs configured for the UE by downlink control information (DCI). The BWP indicated by the DCI is activated, while the other configured BWPs are deactivated. In a carrier (or cell) operating according to TDD operation, the base station can include a bandwidth part indicator (BPI) indicating the activated BWP in the DCI scheduling the PDSCH or PUSCH to change the UE's DL / UL BWP pair. The UE can receive the DCI scheduling the PDSCH or PUSCH and can identify the activated DL / UL BWP pair based on the BPI. In the case of a downlink carrier (or cell) operating according to FDD operation, the base station can include the BPI indicating the activated BWP in the DCI scheduling the PDSCH to change the UE's DL BWP. In the case of an uplink carrier (or cell) operating according to FDD operation, the base station can include the BPI indicating the activated BWP in the DCI scheduling the PUSCH to change the UE's UL BWP.

[0104] Figure 8 It is a conceptual diagram illustrating carrier aggregation.

[0105] Carrier aggregation is a method in which a UE uses multiple frequency blocks or (in a logical sense) cells configured with UL resources (or component carriers) and / or DL resources (or component carriers) as a large logical frequency band so that a wireless communication system can use a wider frequency band. A component carrier can also be referred to by terms such as primary cell (PCell) or secondary cell (SCell) or primary SCell (PScell). However, hereinafter, for the sake of convenience of description, the term "component carrier" is used.

[0106] Reference Figure 8 , as an example of a 3GPP NR system, the entire system bandwidth can include up to 16 component carriers, and each component carrier can have a bandwidth of up to 400 MHz. A component carrier can include one or more physically contiguous subcarriers. Although each component carrier is shown in Figure 8 as having the same bandwidth, this is merely an example, and each component carrier can have a different bandwidth. Additionally, although each component carrier is shown as being adjacent to each other on the frequency axis, the figures are shown in a logical concept, and each component carrier can be physically adjacent to each other or can be spaced apart.

[0107] Different center frequencies can be used for each component carrier. Additionally, a common center frequency can be used in physically adjacent component carriers. Assuming that in the Figure 8 embodiment all component carriers are physically adjacent, the center frequency A can be used in all component carriers. Additionally, assuming that the respective component carriers are not physically adjacent to each other, the center frequency A and the center frequency B can be used in each component carrier.

[0108] When expanding the total system bandwidth through carrier aggregation, the frequency band used for communicating with each UE can be defined in units of component carriers. UE A can use 100 MHz as the total system bandwidth and use all five component carriers to perform communication. UE B 1 ~B 5 can only use a 20 MHz bandwidth and use one component carrier to perform communication. UE C 1 and C 2 can respectively use a 40 MHz bandwidth and use two component carriers to perform communication. These two component carriers can be logically / physically adjacent or not adjacent. UE C 1 represents the case of using two non-adjacent component carriers, while UE C 2 represents the case of using two adjacent component carriers.

[0109] Figure 9 is a diagram for explaining single-carrier communication and multi-carrier communication. In particular, Figure 9(a) shows a single - carrier sub - frame structure and Figure 9 (b) shows a multi - carrier sub - frame structure.

[0110] Reference Figure 9 (a), in the FDD mode, a general wireless communication system can perform data transmission or reception through a DL frequency band and a corresponding UL frequency band. In another specific embodiment, in the TDD mode, the wireless communication system can 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. Reference Figure 9 (b), three 20 - MHz component carriers (CCs) can be aggregated into each of the UL and DL, enabling support for a 60 - MHz bandwidth. Each CC can be adjacent or non - adjacent to each other in the frequency domain. Figure 9 (b) shows a case where the bandwidths of the UL CC and the DL CC are the same and symmetric, but the bandwidth of each CC can be determined independently. In addition, asymmetric carrier aggregation with different numbers of UL CCs and DL CCs is possible. The DL / UL CCs allocated / configured to a specific UE through RRC can be called the serving DL / UL CCs of the specific UE.

[0111] The base station can communicate with the UE by activating some or all of the serving CCs of the UE or deactivating some CCs. The base station can change the CCs to be activated / deactivated and the number of CCs to be activated / deactivated. If the base station allocates the 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 re - configured or the UE is switched. A CC not deactivated by the UE is called the primary CC (PCC) or primary cell (PCell), while the CCs that the base station can freely activate / deactivate are called secondary CCs (SCCs) or secondary cells (SCells).

[0112] Meanwhile, 3GPP NR uses the concept of a cell to manage radio resources. A cell is defined as a combination of DL resources and UL resources, i.e., a combination of a DL CC and a UL CC. A cell can be configured with DL resources alone or can be configured with a combination of DL resources and UL resources. When carrier aggregation is supported, the link between the carrier frequency of the DL resources (or DL CC) and the carrier frequency of the UL resources (or UL CC) can 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 called the PCell, and the cell corresponding to the SCC is called the SCell. The carrier corresponding to the PCell in the DL is the DL PCC, and the carrier corresponding to the PCell in the UL is the UL PCC. Similarly, the carrier corresponding to the SCell in the DL is the DL SCC, and the carrier corresponding to the SCell in the UL is the UL SCC. Depending on the UE capabilities, a serving cell can be configured with one PCell and zero or more SCells. In the case of a UE in the RRC_CONNECTED state that is not configured for carrier aggregation or does not support carrier aggregation, there is only one serving cell configured with only the PCell.

[0113] As described above, the term "cell" used in carrier aggregation is distinguished from the term "cell" referring to a geographical area that provides communication services through a base station or a set of antennas. That is, a component carrier can 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, to distinguish between the cell representing a geographical area and the cell in carrier aggregation, in the present disclosure, the cell in carrier aggregation is referred to as a CC, and the cell of the geographical area is referred to as a cell.

[0114] Figure 10 is a diagram showing an example in which the cross-carrier scheduling technique is applied. When cross-carrier scheduling is set, the control channel transmitted through the first CC can use the Carrier Indicator Field (CIF) to schedule the data channel transmitted through the first CC or the second CC. The CIF is included in the DCI. In other words, a scheduling cell is set, and the DL grant / UL grant transmitted in the PDCCH area of the scheduling cell schedules the PDSCH / PUSCH of the scheduled cell. That is, there is a search area for multiple component carriers in the PDCCH area of the scheduling cell. The PCell can basically be the scheduling cell, and a specific SCell can be designated as the scheduling cell by the upper layer.

[0115] In Figure 10In the embodiments, it is assumed that three DL CCs are combined. Here, it is assumed that DL component carrier #0 is the DLPCC (or PCell), and DL component carriers #1 and #2 are DL SCCs (or SCell). In addition, it is assumed that the DLPCC is set as the PDCCH monitoring CC. When cross-carrier scheduling is not configured by UE-specific (or UE group-specific or cell-specific) higher layer signaling, the CIF is disabled, and each DL CC can send only the PDCCH for scheduling its PDSCH without the CIF according to the NR PDCCH rules (non-cross-carrier scheduling, self-carrier scheduling). At the same time, if cross-carrier scheduling is configured by UE-specific (or UE group-specific or cell-specific) higher layer signaling, the CIF is enabled, and a specific CC (e.g., the DL PCC) can use the CIF to send not only the PDCCH for scheduling the PDSCH of DL CC A but also the PDCCH for scheduling the PDSCH of another CC (cross-carrier scheduling). On the other hand, no PDCCH is sent in another DL CC. Therefore, the UE monitors the PDCCH without the CIF to receive the self-carrier scheduled PDSCH according to whether cross-carrier scheduling is configured for the UE, or monitors the PDCCH with the CIF to receive the cross-carrier scheduled PDSCH.

[0116] On the other hand, Figure 9 and Figure 10 FIG. illustrates the subframe structure of the 3GPP LTE-A system, and the same or similar configuration can be applied to the 3GPP NR system. However, in the 3GPP NR system, Figure 9 and Figure 10 the subframe can be replaced by time slots.

[0117] Figure 11 is a block diagram showing the configurations of a UE and a base station according to an embodiment of the present disclosure.

[0118] In the embodiments of the present disclosure, the UE can be implemented using various types of wireless communication devices or computing devices that are guaranteed to be portable and mobile. The UE can be referred to as a user equipment (UE), a station (STA), a mobile subscriber (MS), etc. In addition, in the embodiments of the present disclosure, the base station controls and manages a cell corresponding to a service area (e.g., a macro cell, a femto cell, a pico cell, etc.), and performs functions such as signal transmission, channel assignment, channel monitoring, self-diagnosis, relaying, etc. The base station can be referred to as a next-generation node B (gNB) or an access point (AP).

[0119] As shown in the drawings, a 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.

[0120] First, the processor 110 may execute various instructions or processes and process data within the UE 100. In addition, the processor 110 may control the overall operation of each unit including the UE 100 and may control the transmission / reception of data between the units. Here, the processor 110 may be configured to execute operations according to the 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.

[0121] 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 multiple network interface cards (NICs) in an internal or external form, such as cellular communication interface cards 121 and 122 and unlicensed band communication interface cards 123. In the drawings, the communication module 120 is shown as an overall integrated module, but different from the drawings, each network interface card can be independently arranged according to the circuit configuration or usage.

[0122] The cellular communication interface card 121 may transmit or receive radio signals with at least one of the base station 200, an external device, and a server using a mobile communication network and provide cellular communication services in a first frequency band based on instructions from the processor 110. According to an embodiment, the cellular communication interface card 121 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 121 may independently perform cellular communication with at least one of the base station 200, an external device, and a server in a frequency band below 6 GHz supported by the corresponding NIC module according to cellular communication standards or protocols.

[0123] The cellular communication interface card 122 may transmit or receive radio signals with at least one of the base station 200, an external device, and a server using a mobile communication network and provide cellular communication services in a second frequency band based on instructions from the processor 110. According to an embodiment, the cellular communication interface card 122 may include at least one NIC module using 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, an external device, and a server in a frequency band above 6 GHz supported by the corresponding NIC module according to cellular communication standards or protocols.

[0124] The unlicensed band communication interface card 123 transmits or receives radio signals with at least one of the base station 200, external devices, and servers by using a third band as 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 an unlicensed band. For example, the unlicensed band may be a band of 2.4 GHz, 5 GHz, 6 GHz, 7 GHz, or higher than 52.6 GHz. 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, external devices, and servers independently or dependently according to the unlicensed band communication standard or protocol of the band supported by the corresponding NIC module.

[0125] The memory 130 stores control programs used in the UE 100 and various data therefor. Such control programs may include prescribed programs required to perform wireless communication with at least one of the base station 200, external devices, and servers.

[0126] 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 by using various input means, and the processor 110 may control the UE 100 based on the received user input. In addition, the user interface 140 may perform output based on instructions from the processor 110 by using various output means.

[0127] Next, the display unit 150 outputs various images on the display screen. The display unit 150 may output various display objects, such as content executed by the processor 110 or a user interface, based on control instructions from the processor 110.

[0128] In addition, the base station 200 according to an embodiment of the present disclosure may include a processor 210, a communication module 220, and a memory 230.

[0129] First, the processor 210 may execute various instructions or programs and process internal data of the base station 200. In addition, the processor 210 may control the overall operation of each unit 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 the embodiments described in the present disclosure. For example, the processor 210 may signal a time slot configuration and perform communication according to the signaled time slot configuration.

[0130] 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 multiple network interface cards in an internal or external form, such as cellular communication interface cards 221 and 222 and unlicensed band communication interface card 223. In the drawings, the communication module 220 is shown as an overall integrated module, but different from the drawings, each network interface card can be independently arranged according to the circuit configuration or usage.

[0131] The cellular communication interface card 221 may transmit or receive radio signals with at least one of the base station 100, an external device, and a server using a mobile communication network and provide cellular communication services in a first band based on instructions from the processor 210. According to an embodiment, the cellular communication interface card 221 may include at least one NIC module that uses a 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, an external device, and a server in a band less than 6 GHz supported by the corresponding NIC module according to cellular communication standards or protocols.

[0132] 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 using a mobile communication network and provide cellular communication services in a second 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 that uses a band of 6 GHz 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, an external device, and a server in a band of 6 GHz or higher supported by the corresponding NIC module according to cellular communication standards or protocols.

[0133] The unlicensed band communication interface card 223 transmits or receives radio signals with at least one of the base station 100, an external device, and a server using a third 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 an unlicensed band. For example, the unlicensed band may be a band of 2.4 GHz, 5 GHz, 6 GHz, 7 GHz, or higher than 52.6 GHz. 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, an external device, and a server independently or dependently according to unlicensed band communication standards or protocols of the band supported by the corresponding NIC module.

[0134] Figure 11FIG. 0 is a block diagram of 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 the apparatus. Thus, the foregoing elements of the apparatus may be installed in a single chip or multiple chips according to the design of the apparatus. In addition, a part of the configuration of the UE 100, such as a user interface 140, a display unit 150, etc., may be selectively provided in the UE 100. In addition, a user interface 140, a display unit 150, etc. may be additionally provided in the base station 200 when necessary.

[0135] In a TDD or unpaired spectrum system, the base station may configure a time slot format for the UE. The time slot format may refer to the symbol type in the time slot. The symbol type may be at least one of a downlink symbol (DL symbol), an uplink symbol (UL symbol), or a flexible symbol. The base station may configure the symbol type of the time slot in the radio frame for the UE. The flexible symbol may refer to a symbol that is not configured as a downlink symbol or an uplink symbol.

[0136] The UE may be semi-statically configured with information about the type of each symbol in the time slot by receiving information about the type of each symbol in the time slot from the base station via a cell-specific or cell-common radio resource control (RRC) signal. Here, the cell-specific (or, cell-common or UE-common) RRC signal includes tdd-UL-DL-ConfigurationCommon. In addition, the UE may be semi-statically configured with information about the type of each symbol in the time slot by receiving information about the type of each symbol in the time slot from the base station via SIB1. In addition, the UE may be semi-statically configured with information about the type of each symbol in the time slot by receiving information about the type of each symbol in the time slot from the base station via a UE-specific or UE-dedicated RRC signal. The base station may configure / set the type of each symbol in the time slot for the UE by using the information about the type of each symbol in the time slot.

[0137] When the UE receives information on the type of each symbol in a time slot from the base station via a cell-specific RRC signal, the information configured by the cell-specific RRC signal may include at least one of the following: 1) the period of the cell-specific time slot configuration, 2) the number of time slots including only DL symbols starting from the starting time slot of the period, 3) the number of DL symbols starting from the first symbol of the time slot immediately following the last time slot including only DL symbols, 4) the number of time slots including only UL symbols starting from the last time slot of the period, and 5) the number of UL symbols in the time slot immediately preceding the last time slot including only uplink symbols (in the direction backward from the last time slot of the period). Here, a symbol not configured as a DL symbol or a UL symbol is a flexible symbol. Additionally, when the UE receives information on the type of each symbol in a time slot from the base station via a cell-specific RRC signal, the information on the type of each symbol may include up to two time slot patterns. In such a case, the two patterns may be applied to the symbols in the time domain in sequence. The DL symbols, UL symbols, and flexible symbols configured based on the cell-specific RRC signal or SIB1 may be referred to as cell-specific DL symbols, cell-specific UL symbols, and cell-specific flexible symbols, respectively.

[0138] When the UE receives information on the type of each symbol in a time slot from the base station via a UE-specific RRC signal, the cell-specific flexible symbol may be configured as a DL symbol or a UL symbol via the UE-specific RRC signal. Here, the UE-specific RRC signal includes tdd-UL-DL-ConfigurationDedicated. In such a case, the information configured by the UE-specific RRC signal may include at least one of the following: 1) the index of the time slot within the time slot configuration period, 2) the number of DL symbols starting from the first symbol of the time slot indicated by the index, and 3) the number of UL symbols starting from the last symbol of the time slot indicated by the index. Here, a symbol not configured as a DL symbol or a UL symbol is a flexible symbol. Additionally, the UE may be configured such that all symbols in the time slot are DL symbols, or may be configured such that all symbols in the time slot are UL symbols. The DL symbols, UL symbols, and flexible symbols configured based on the UE-specific RRC signal may be referred to as UE-specific DL symbols, UE-specific UL symbols, and UE-specific flexible symbols, respectively.

[0139] The base station may send information on the time slot format to the UE via a time slot format indicator (SFI) in DCI format 2_0 included in the group common (GC)-PDCCH. For a UE receiving information on the time slot format, the GC-PDCCH may be CRC scrambled using the SFI-RNTI. Hereinafter, the SFI sent via the GC-PDCCH may be described as a dynamic SFI.

[0140] The UE can receive dynamic SFI through the GC-PDCCH to receive an indication of whether the symbols in a time slot are cell-specific flexible symbols or UE-specific flexible symbols, downlink symbols, uplink symbols, or flexible symbols. In other words, the flexible symbols configured semi-statically only for the UE can be indicated as one of the downlink symbols, uplink symbols, and flexible symbols via the dynamic SFI. The UE may not expect that the downlink symbols or uplink symbols configured semi-statically will be indicated as different types of symbols by the dynamic SFI. The UE can perform blind decoding in each monitoring period configured by the base station to receive the GC-PDCCH that transmits the DCI format 2_0 including the dynamic SFI. When the UE successfully receives the GC-PDCCH by performing blind decoding, the UE can apply the information on the time slot format indicated by the dynamic SFI starting from the time slot in which the GC-PDCCH has been received.

[0141] The base station can configure a combination of time slot formats that can be indicated by the dynamic SFI for the UE. The time slot format combination can be used for each of 1 to 256 time slots, and a time slot format combination for one of 1 to 256 time slots can be configured for the UE by the dynamic SFI. The dynamic SFI can include an index indicating the time slot to which the time slot format combination is applied. Table 3 shows the time slot format combinations for each time slot (see 3GPP TS38.213).

[0142] [Table 3]

[0143]

[0144] In Table 3, D represents downlink symbols, U represents uplink symbols, and F represents flexible symbols. As shown in Table 3, up to two DL / UL switches can be allowed within one time slot.

[0145] In this specification, the terms "configured", "set", and "indicated" can be used interchangeably. That is, the terms "configured", "set", and "indicated" can have the same meaning, and similarly, the terms "configured", "set", and "indicated" can have the same meaning.

[0146] Sub-band full duplex: Spectrum partitioning

[0147] Figures 12 to 13 The figure illustrates a sub-band configuration method according to an embodiment of the present disclosure.

[0148] In TDD or unpaired spectrum, when configuring or indicating a time slot format for a UE, only limited time domain resources can be allocated as UL resources, resulting in problems such as reduced uplink coverage, increased latency, and reduced capacity. To solve this problem, a solution is being discussed in which specific time domain resources within a cell are divided into multiple subbands in the frequency domain and used for downlink reception and uplink transmission.

[0149] Reference Figure 12 , the UE can receive TDD configuration information to be semi-statically configured with a time slot format, or can receive SFI to dynamically indicate using the time slot format. Here, the TDD configuration information can include cell-specific (or cell-common) TDD configuration information (e.g., tdd-UL-DL-ConfigurationCommon) or UE-specific TDD configuration information (e.g., tdd-UL-DL-ConfigurationDedicated). D (or DL) represents the downlink, U (or UL) represents the uplink, F represents flexible, and D / F (or DL / F) represents D (or DL) or F. Then, the UE can be configured with multiple subbands in the frequency domain for a specific time domain resource (e.g., at least one time slot / symbol) (n2 to n3) through subband configuration / indication from the base station. The subband configuration / indication information can include information about a set of consecutive RBs (e.g., starting RB, number of RBs, etc.). The multiple subbands can be subbands with the same or different formats. The subband format can include a downlink (D or DL) subband and an uplink (U or UL) subband. The D (or DL) subband can include one or more downlink RBs, and the U (or UL) subband can include one or more uplink RBs. A downlink RB can refer to a resource available for downlink reception, and an uplink RB can refer to a resource available for uplink transmission.

[0150] Reference Figure 13, multiple sub - bands can be (dynamically) indicated to a UE in the frequency domain relative to a semi - static configuration (e.g., TDD configuration) or a downlink (D or DL) time slot or symbol dynamically indicated from a base station (e.g., SFI). In the figure, the multiple sub - bands include two D (or DL) sub - bands and one U (or UL) sub - band. In such a case, the resources configured or indicated to receive a downlink signal or channel in the same symbol may overlap in the time domain with the resources configured or indicated to transmit an uplink signal or channel. For example, when downlink reception (e.g., CSI - RS) is scheduled in a D (or DL) sub - band and uplink transmission (e.g., PUSCH) is scheduled in a U (or UL) sub - band, the reception and transmission may overlap in at least one symbol (the 5th or 6th symbol). At the same time, when configuring sub - bands, the base station can perform both downlink transmission and uplink reception in the same sub - band symbol (full - duplex), while a UE that only supports half - duplex can only perform downlink reception or uplink transmission in the same sub - band symbol. Here, the sub - band symbol refers to the symbol in which the sub - band is configured. Therefore, when downlink reception and uplink transmission overlap in the same sub - band symbol (see the circled part in the figure), the UE and the base station can operate as follows.

[0151] 1) When downlink reception and uplink transmission belong to different UEs,

[0152] - Each UE can perform downlink reception or uplink transmission without restriction.

[0153] - The base station can perform downlink transmission and uplink reception simultaneously.

[0154] 2) When downlink reception and uplink transmission belong to the same UE,

[0155] - The UE cannot perform downlink reception and uplink transmission simultaneously. Therefore, to resolve the conflict between downlink reception and uplink transmission, the downlink reception and / or uplink transmission of the UE can be restricted.

[0156] - The base station can perform downlink transmission and uplink reception simultaneously. However, because the downlink reception and / or uplink transmission of the UE is restricted, the same restriction can be applied to the base station.

[0157] Here, the conflict situation may not be limited to the case where multiple sub - bands are dynamically indicated to the UE in the frequency domain for downlink time slots or symbols with semi - static configuration or dynamic indication from the base station. That is to say, the conflict situation can also include the case where multiple sub - bands are semi - statically configured to the UE for downlink time slots or symbols with semi - static configuration or dynamic indication from the base station.

[0158] In addition, the collision situation may not be limited to the case where multiple subbands are dynamically indicated to the UE for flexible time slots or symbols configured or dynamically indicated by the base station semi-statically. That is to say, the collision situation may also include the case where multiple subbands are semi-statically configured to the UE for flexible time slots or symbols configured or dynamically indicated by the base station semi-statically.

[0159] Example: Subband-based full duplex and signal / channel transmission / reception

[0160] First, summarize the terms used in this disclosure.

[0161] - Subband-based full duplex: This refers to a method that supports simultaneous transmission and reception by using subbands within a cell / BWP. It can be referred to as subband non-overlapping full duplex (SBFD). Here, a subband refers to a frequency band configured / indicated for SBFD operation within a cell / BWP. A subband can be configured as a set of consecutive (P)RBs. For examples of subband configurations / formats, reference can be made to Figure 12 and 13 . For example, for unpaired spectrum (i.e., TDD cell / BWP), the UL subband can be configured on DL time slots / symbols, or the UL subband can be configured on flexible time slots / symbols. When subbands are configured in a cell / BWP, the cell / BWP may include subband intervals and non-subband intervals for performing TDM in the time domain.

[0162] - Subband interval: This refers to the time interval for setting / indicating subbands on a cell / BWP. For example, the subband interval includes the time interval for configuring / indicating the UL subband. For example, the subband interval includes the time slot for configuring / indicating the UL subband. For example, the subband interval includes the symbol (or symbol set) for configuring / indicating the UL subband. The subband interval includes subband time slots and / or subband symbols. The subband interval may include one or more subbands in the frequency domain. When multiple subbands are configured in the subband interval, the subbands are FDM. Multiple subbands (DL subbands or UL subbands) in the subband interval can be configured such that they do not overlap with each other (non-overlapping) in the frequency domain.

[0163] - Non-subband interval: This refers to the time interval when subbands are not configured / indicated on a cell / BWP. The non-subband interval includes non-subband time slots and / or non-subband symbols. The non-subband interval refers to a legacy interval or a normal interval. The non-subband band includes at least one of DL symbols, flexible symbols, and UL symbols depending on the time slot format. For example, when subbands are not configured / indicated in the UL BWP, the non-subband interval includes UL time slots / symbols.

[0164] - Legacy NR system: This refers to a system that operates according to traditional NR methods because it does not support or configure subband-based full duplex operation.

[0165] The problem to be solved in this disclosure relates to when a signal or channel that a UE is configured or instructed to receive conflicts in the same symbol as a random access channel occasion (RO), which is an occasion for physical random access channel (PRACH) transmission. The RO is configured within a PRACH time slot. The PRACH time slot is configured periodically in radio frames based on a PRACH configuration index at a higher layer (e.g., RRC) (see 3GPP TS38.211 V16.9.0 (2022-06), Tables 6.3.3.2-2 to 6.3.3.2-4). Within a PRACH time slot, one or more ROs can be configured in the time domain, and multiple ROs can be configured in the frequency domain. The number of symbols and the number of resource blocks (RBs) occupied by one RO can vary depending on the PRACH / preamble format. Figure 14 The figure shows multiple ROs configured within a PRACH time slot. The figure illustrates a case where ROs are configured for two symbol sets in the time domain (TDM) and for five RBs in the frequency domain (FDM) within a PRACH time slot. In addition, a case where one RO includes 76 symbols in the time domain is also illustrated. In other words, a case where one symbol set constituting one RO includes seven symbols in the time domain is illustrated.

[0166] Whether an RO is valid can be determined based on the time slot format configuration of the PRACH time slot. The UE can perform uplink transmission (e.g., PRACH) or downlink reception (e.g., physical downlink shared channel (PDSCH), channel state information reference signal (CSI-RS)) based on whether the RO is valid. Specifically, the UE can perform PRACH transmission for a valid RO. In addition, when a valid RO (including gap symbols) and downlink reception (e.g., PDSCH reception or CSI-RS reception) overlap in the time domain, the UE can skip the downlink reception. On the other hand, when the RO is invalid, the UE can refrain from performing PRACH transmission for that RO. In addition, even when an RO (including gap symbols) and downlink reception overlap in the time domain, when the RO is invalid, the UE can perform downlink reception normally. In a conventional New Radio (NR) system, the UE can determine a valid RO in TDD or unpaired spectrum as follows. Specifically, whether a valid RO can be determined based on whether tdd-UL-DL-ConfigurationCommon, which is information about symbol types, is configured for the UE. tdd-UL-DL-ConfigurationCommon can be received via a cell-specific (or cell-common) RRC signal or system information block 1 (SIB1).

[0167] – When tdd-UL-DL-ConfigurationCommon is not configured for the UE:

[0168] When the RO within a PRACH time slot does not precede the SS / PBCH block within the same PRACH time slot in the time domain and starts at least N gap symbols after the reception symbol of the last SS / PBCH block, the RO can be valid. Here, the reception symbol of the last SS / PBCH block refers to the last reception symbol of the last SS / PBCH block before the RO.

[0169] – When tdd-UL-DL-ConfigurationCommon is configured for the UE ( Figure 15 ):

[0170] When the RO is on a UL symbol, the RO within the PRACH time slot is valid. In addition, when the RO within the PRACH time slot starts at least N gap symbols after the last DL symbol, does not precede the SS / PBCH block within the same PRACH time slot in the time domain ( Figure 15 (a)), and starts at least N gap symbols after the reception symbol of the last SS / PBCH block ( Figure 15 (b)), the RO can be valid. Here, the last DL symbol refers to the last DL symbol before the RO in the DL symbol set configured by tdd-UL-DL-ConfigurationCommon. In the figure, the D symbol refers to the cell-common (or cell-specific) DL symbol, the F symbol refers to the cell-common (or cell-specific) flexible symbol, and the U symbol refers to the cell-common (or cell-specific) UL symbol.

[0171] Table 4 shows N gap . In the case of PRACH preamble format B4, N gap can be 0.

[0172] [Table 4]

[0173] Preamble SCS <![CDATA[N gap > 1.25 kHz or 5 kHz 0 15 kHz or 30 kHz or 60 kHz or 120 kHz 2

[0174] According to the disclosure of this specification, for the downlink / flexible time slots or symbols semi-statically configured or dynamically indicated by the base station, multiple subbands can be semi-statically configured or dynamically indicated to the UE in the frequency domain. Here, the multiple subbands can include at least one UL subband, and as another example, can include at least one DL subband and at least one UL subband. In this case, in addition to the above method, according to an example of the present disclosure, the UE can determine the valid RO in the time slot or symbol as follows.

[0175] – When tdd-UL-DL-ConfigurationCommon is not configured for the UE:

[0176] When the RO is within an uplink subband, and the RO does not precede the SS / PBCH block within the PRACH time slot in the time domain, and starts at least N gap symbols after the last received symbol of the SS / PBCH block, the RO within the PRACH time slot can be valid. Here, the last received symbol of the SS / PBCH block refers to the last received symbol of the last SS / PBCH block before the RO.

[0177] – When tdd-UL-DL-ConfigurationCommon is configured for the UE ( Figures 16 to 19 ):

[0178] When the RO within the PRACH time slot is on a UL symbol, the RO can be valid ( Figure 16 ). When the RO within the PRACH time slot is within a UL subband ( Figure 16 ), and the RO starts at least N gap symbols after the last DL symbol, and does not precede the SS / PBCH block within the PRACH time slot in the time domain ( Figures 17 - 18 ), and starts at least N gap symbols after the last received symbol of the SS / PBCH block ( Figure 19 ), the RO can be valid. Since UL transmission is allowed in the UL subband, the last DL symbol is limited to the DL symbols that are not configured or indicated as UL subbands (i.e., non-subband symbols). That is, the subband symbols are not included in the last DL symbol. Referring to Figure 17 and Figure 18 , the last DL symbol refers to the last DL symbol before the RO in the DL symbol set configured by tdd-UL-DL-ConfigurationCommon excluding the symbols of the configured UL subband (the last symbol in time slot #p - 1 or the last symbol in time slot #m - 1).

[0179] In Figures 16 to 19 , m, p, and q represent time slot indices. m, p, and q can be defined according to the PRACH time slot configuration, and can be configured continuously or discontinuously.

[0180] Based on the valid RO (or based on whether the RO is valid), the UE can perform UL transmission or DL reception. For example, the UE can perform PRACH transmission in the valid RO. In addition, when the valid RO (including gap symbols) and downlink reception (e.g., PDSCH reception) overlap in the time domain, according to the disclosure of the present invention, the PRACH transmission or DL reception by the UE can be restricted. This will be described below with reference to Figures 20 to 23This is described as follows. On the one hand, the UE is not allowed to perform PRACH transmission in an invalid RO. In addition, the downlink reception by the UE is not restricted by the invalid RO.

[0181] For the downlink / flexible time slots or symbols semi-statically configured or dynamically indicated by the base station, multiple sub-bands can be semi-statically configured or dynamically indicated to the UE in the frequency domain. In this case, the resources configured or indicated for receiving DL signals / channels and the valid ROs may overlap in the same symbol. A UE that only supports half-duplex may only be able to perform DL reception or UL transmission in the same symbol, and the UE is not allowed to receive (e.g., skip receiving) DL signals / channels (e.g., PDCCH, PDSCH, or CSI-RS) in (i) the valid RO and (ii) the N gap symbols before the valid RO. On the other hand, when the RO of the overlapping DL signal / channel is invalid, the DL signal / channel can be received normally.

[0182] For example, referring to Figure 20 , the UE can be configured or indicated to receive a PDSCH including a symbol that overlaps with six symbols corresponding to (i) the valid RO and (ii) the N gap symbols before the valid RO. In this case, in order to protect the PRACH transmission in the valid RO, the UE is not allowed to receive the PDSCH. On the other hand, when there is no actual PRACH transmission in the valid RO, even if the resources configured or indicated for receiving the PDSCH in that time slot are available, a UE that does not receive the PDSCH may reduce the downlink coverage by not receiving the PDSCH. Hereinafter, the UE operation to solve this problem is proposed as follows. Hereinafter, the valid RO can include N gap symbols. That is to say, the valid RO can be {N gap symbols + RO}. For the N gap symbols, Table 4 can be referred to.

[0183] 1) PDSCH (or SPS PDSCH) versus the valid RO ( Figures 20 to 23 )

[0184] In the frequency domain, multiple subbands can be configured or indicated to the UE for semi - static configuration or dynamic indication of downlink / flexible time slots or symbols. Additionally, the UE can be indicated to receive the PDSCH via a DCI format (e.g., DCI format 1_0, 1_1, or 1_2) for DL scheduling in the corresponding time slot or symbol (i.e., subband time slot / symbol). Further, the UE can be configured to receive the semi - persistent scheduling (SPS) PDSCH via a higher layer (e.g., RRC) in the corresponding time slot or symbol (i.e., subband time slot / symbol). When the PDSCH (or SPS PDSCH) and the valid RO overlap in the same symbol in the corresponding time slot or symbol, the UE operates as follows.

[0185] According to the first embodiment, (a) when there is no actual PRACH transmission, the PDSCH (or SPS PDSCH) can be received, and (b) when there is an actual PRACH transmission, the PRACH can be sent and the PDSCH is not received. In the first embodiment, to solve the above - mentioned problem, at least when there is no actual PRACH transmission, the PDSCH (or SPS PDSCH) can be received, thereby preventing the reduction of downlink coverage.

[0186] According to the second embodiment, (a) when there is no actual PRACH transmission, the PDSCH (or SPS PDSCH) can be received, and (b) when there is an actual PRACH transmission, the PRACH can be sent and the PDSCH (or SPS PDSCH) can be rate - matched and received. For example, referring to Figure 20 , the PDSCH (or SPS PDSCH) is indicated to be received at 14 symbols * 20 RBs, the valid RO is determined to be 6 symbols * 6 RBs, and the resources indicated for receiving the PDSCH (or SPS PDSCH) can include all valid ROs. In this case, the UE can rate - match and receive the PDSCH (or SPS PDSCH) at the 6 symbols * 6 RBs of the overlapping valid RO among the 14 symbols * 20 RBs indicated for PDSCH (or SPS PDSCH) reception, and send the PRACH in the valid RO. In the second embodiment, even when there is an actual PRACH transmission in the overlapping symbol, the UE can rate - match and receive the PDSCH (or SPS PDSCH) in the resources where downlink reception is possible. Therefore, the reduction of downlink coverage can be prevented.

[0187] The first embodiment or the second embodiment may be applied only to PRACH transmissions configured / originated by a higher layer (e.g., Media Access Control (MAC)). That is, the UE may not expect to detect in the same symbol a DCI indicating PDSCH (or SPS PDSCH) reception and a DCI indicating PRACH transmission.

[0188] Reference Figure 21 , the UE may be configured or indicated by the base station to receive the PDSCH in eight symbols, and may determine six symbols as the valid RO. In this case, the valid RO and the PDSCH reception may not overlap in the frequency domain, but may overlap in the time domain (i.e., two symbols). In this case, the UE may operate differently depending on whether the PDSCH reception is configured by a higher layer (e.g., Radio Resource Control (RRC)) or indicated by a DCI. Here, the PDSCH reception configured by a higher layer includes SPS PDSCH reception.

[0189] According to one embodiment, when the PDSCH reception is indicated by a DCI format for DL scheduling (e.g., DCI format 1_0, 1_1, or 1_2), the UE may receive the PDSCH (i.e., prioritize the PDSCH reception). Reference Figure 22 , the UE may be indicated to receive the PDSCH in eight symbols within a downlink subband, and the valid RO may be determined as six symbols. In this case, the UE may receive the PDSCH in the eight symbols indicated by the DCI, and may not transmit a PRACH in the valid RO. This means that at least when the base station indicates to the UE to receive the downlink via a DCI, the UE may determine to prioritize the downlink reception for downlink coverage and not transmit a PRACH. On the other hand, different from a UE that supports half-duplex communication on a subband, the base station supports full-duplex communication. Thus, as Figure 22 shown, even when the PRACH transmission in the valid RO in the subband by the UE is restricted by the UE's PDSCH reception, the base station supporting full-duplex operation may transmit the PDSCH to the UE in the valid RO while receiving a PRACH from another UE.

[0190] According to another embodiment, when the UE is configured by a higher layer (e.g., RRC) to receive the PDSCH, the UE may rate-match and receive the PDSCH, and may perform a PRACH transmission in the valid RO. For example, the UE may rate-match and receive except for the symbols overlapping the valid RO and the symbols corresponding to the RxTxSwitchingGap (i.e., the gap between downlink reception and uplink transmission (N gap，Rx-Tx ), and / or the gap between uplink transmission and downlink reception (N gap，Tx-Rx), where the PDSCH in symbols other than the symbols configured differently depending on the subcarrier spacing (SCS). Here, N gap，Rx-Tx and N gap，Tx-Rx can be defined independently of each other, or can be defined as the same value. For convenience, the switching gap is summarized and referred to as N gap . N gap can refer to N gap,Rx-Tx and / or N gap,Tx-Rx . Referring to Figure 23 , the UE can be configured by a higher layer (e.g., RRC) to receive the PDSCH in eight symbols within a downlink subband, and can determine the effective RO as six symbols. In this case, the UE can rate-match the PDSCH for PDSCH reception by two symbols relative to the overlapping effective RO and N gap = 2 (i.e., set to N gap,Rx-Tx = 2, and not limited thereto) symbols before the effective RO, to receive the PDSCH with a length of four symbols. Additionally, the UE can even transmit the PRACH in the effective RO. This is a method to prevent the downlink coverage from decreasing by rate-matching on resources where downlink reception is possible and receiving the PDSCH, and also allows the UE to perform PRACH transmission when the UE wants to perform transmission in the RO.

[0191] 2) CSI-RS versus effective RO

[0192] In the frequency domain, multiple subbands can be configured or indicated to the UE for semi-static configuration or dynamic indication of downlink / flexible time slots or symbols. Additionally, the UE can be indicated to receive CSI-RS via a DCI format (e.g., DCI format 1_0, 1_1, or 1_2) for DL scheduling on the corresponding time slot or symbol (i.e., subband time slot / symbol). When the CSI-RS and the effective RO overlap in the same symbol in a time slot or symbol, the UE operates as follows.

[0193] According to the first embodiment, (a) when there is no actual PRACH transmission, the CSI-RS can be received, and (b) when there is an actual PRACH transmission, the PRACH can be transmitted and the CSI-RS cannot be received. In the first embodiment, to solve the above problems, at least when there is no actual PRACH transmission, the CSI-RS can be received, thereby preventing the reduction of the downlink coverage.

[0194] The first embodiment can be applied only when CSI-RS reception is indicated by DCI and PRACH transmission is configured by a higher layer (e.g., MAC). That is, the UE may not expect to receive CSI-RS from a higher layer and transmit the PRACH in the same symbol.

[0195] 3) CORESET for this valid RO

[0196] In the frequency domain, multiple subbands can be configured or indicated to the UE for semi - static configuration or dynamic indication of downlink / flexible time slots or symbols. Additionally, a CORESET for monitoring the PDCCH on the corresponding time slot or symbol (i.e., subband time slot / symbol) can be configured for the UE. When the CORESET and the valid RO overlap in the same symbol in the corresponding time slot or symbol, the UE operates as follows.

[0197] According to the first embodiment, (a) when there is no actual PRACH transmission, the PDCCH can be monitored, and (b) when there is an actual PRACH transmission, the PRACH can be sent and the PDCCH is not monitored. In the first embodiment, to solve the above - mentioned problem, at least when there is no actual PRACH transmission, the PDCCH can be monitored, thus preventing the reduction of downlink coverage. Additionally, the PDCCH contains control information such as resource allocation for the UE and can thus be optimized.

[0198] The first embodiment can be applied only when the PRACH transmission is configured from a higher layer (e.g., MAC). That is, when the UE is indicated by DCI to send the PRACH on the symbol where the CORESET is configured, the UE cannot monitor the PDCCH regardless of whether the PRACH is actually sent in that symbol.

[0199] When the UE is sending a PRACH for initial cell access (i.e., before RRC connection), the above - mentioned conflict situations between the valid RO and the CORESET, PDSCH, or CSI - RS may not be applicable. That is, in conflict situations, the UE before RRC connection may not monitor the PDCCH or receive the PDSCH or CSI - RS. For example, the UE before RRC connection can operate according to the legacy NR system.

[0200] The methods and systems of the present disclosure are described with respect to specific embodiments, but the configuration elements, parts, or all of the operations of the present disclosure can be implemented using a computer system with a general - purpose hardware architecture.

[0201] The above description of the present disclosure is for illustrative purposes, and those skilled in the art to which the present disclosure pertains will be able to understand that other specific forms can be easily modified without changing the technical spirit or essential features of the present disclosure. Therefore, it should be understood that the above embodiments are illustrative in all aspects and not restrictive. For example, each element described as a type can be implemented in a distributed manner, and similarly, elements described as distributed can also be implemented in a combined form.

[0202] The scope of the present disclosure is indicated by the claims to be described hereinafter rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included within the scope of the present disclosure.

[0203] The scope of the present disclosure is indicated by the claims described hereinafter rather than the detailed specification, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included within the scope of the present disclosure.

Claims

1. A user equipment used in a wireless communication system, the user equipment comprising: a communication module; and a processor configured to control the communication module, wherein the processor is configured to: receive a cell-specific radio resource control (RRC) signal regarding a slot format, the slot format including information about the type of symbols, and the type of symbols including at least one of a downlink (DL) symbol, a flexible symbol, and an uplink (UL) symbol; Determine whether a random access opportunity (RO) in a physical random access channel (PRACH) time slot is valid, the determination including determining whether the RO is valid based on whether the RO starts at least N gap symbols after the last DL symbol; and perform UL transmission or DL reception based on whether the RO is valid, wherein, in at least one slot, a plurality of subbands are configured within a frequency band, the plurality of subbands including DL subbands and UL subbands, and wherein, in the case where the RO exists in the UL subband, based on the DL symbols configured by the cell-specific RRC signal, excluding the symbols in which the UL subband is configured, to determine the last DL symbol.

2. The user equipment according to claim 1, wherein, the cell-specific RRC signal includes common time division duplex (TDD) UL-DL configuration information.

3. The user equipment according to claim 1, wherein, The determination includes that when the RO is within the UL sub-band and does not precede the synchronization signal / physical broadcast channel (SS / PBCH) block within the PRACH time slot in the time domain, starting from at least N gap symbols after the last DL symbol, and starting from at least N gap symbols after the reception symbol of the last SS / PBCH block, determining that the RO is valid.

4. The user equipment according to claim 1, wherein, the determination includes, in the case where the RO exists on the UL symbol set configured by the cell-specific RRC signal, determining that the RO is valid.

5. The user equipment according to claim 1, wherein, Determine N based on the subcarrier spacing (SCS) of the PRACH gap .

6. The user equipment according to claim 5, wherein, The said N gap is determined as follows: - When the SCS of the PRACH is 1.25 kHz or 5 kHz, N gap = 0; and - When the SCS of the PRACH is 15 kHz, 30 kHz, 60 kHz or 120 kHz, N gap = 2.

7. The user equipment according to claim 1, wherein, in the case where the RO is valid, transmit the PRACH in the RO.

8. The user equipment according to claim 1, wherein, in the following cases (a) the RO exists on the UL subband, (b) the RO is valid, and (c) The physical downlink shared channel (PDSCH) scheduled for the user equipment overlaps at least one of the N gap symbols and the RO in the time domain. determine the reception of the PDSCH based on whether the PDSCH has been scheduled by downlink control information (DCI) or a higher layer.

9. The user equipment according to claim 8, wherein, in the following cases (a) the RO exists on the UL subband, (b) the RO is valid, (c) The physical downlink shared channel (PDSCH) scheduled for the user equipment overlaps in the time domain with at least one of the N gap symbols and the RO, and (d) the PDSCH is scheduled by the DCI, - the PDSCH is normally received, and - PRACH transmission is not allowed in the RO.

10. The user equipment according to claim 8, wherein, in the following cases (a) the RO exists on the UL subband, (b) the RO is valid, (c) The PDSCH scheduled for the user equipment overlaps at least one of the N gap symbols and the RO in the time domain, and (d) the PDSCH is scheduled by a higher layer, - the PDSCH is rate-matched and received based on resources so overlapped in the time domain, and - PRACH transmission is allowed in the RO.

11. A method used by a user equipment in a wireless communication system, the method comprising: receive a cell-specific radio resource control (RRC) signal regarding a slot format, the slot format including information about the type of symbols, and the type of symbols including at least one of a downlink (DL) symbol, a flexible symbol, and an uplink (UL) symbol; Determine whether a random access opportunity (RO) in a physical random access channel (PRACH) time slot is valid, the determination including determining whether the RO is valid based on whether the RO starts at least N gap symbols after the last DL symbol; and Based on whether the RO effectively performs UL transmission or DL reception, wherein, in at least one time slot, a plurality of subbands are configured within a frequency band, the plurality of subbands including a DL subband and a UL subband, and wherein, in the case where the RO is present in the UL subband, the last DL symbol is determined by excluding the symbol in which the UL subband is configured, based on the DL symbols configured by the cell-specific RRC signal.

12. The method according to claim 11, wherein, the cell-specific RRC signal includes common time division duplex (TDD) UL-DL configuration information.

13. The method according to claim 11, wherein, The determination includes that, when the RO is within the UL sub-band and does not precede the synchronization signal / physical broadcast channel (SS / PBCH) block within the PRACH time slot in the time domain, starting from at least N gap symbols after the last DL symbol, and starting from at least N gap symbols after the last symbol of the SS / PBCH block reception, determining that the RO is valid.

14. The method according to claim 11, wherein, the determination includes determining that the RO is effective in the case where the RO is present on the set of UL symbols configured by the common RRC signal.

15. The method according to claim 11, wherein, Determine N based on the subcarrier spacing (SCS) of the PRACH gap .

16. The method according to claim 15, wherein, The said N gap is determined as follows: - When the SCS of the PRACH is 1.25 kHz or 5 kHz, N gap = 0; and - When the SCS of the PRACH is 15 kHz, 30 kHz, 60 kHz or 120 kHz, N gap = 2.

17. The method according to claim 11, wherein, in the case where the RO is effective, the PRACH is transmitted in the RO.

18. The method according to claim 11, wherein, in the following cases (a) the RO is present on the UL subband, (b) the RO is effective, and (c) The physical downlink shared channel (PDSCH) scheduled for the user equipment overlaps in the time domain with at least one of the N gap symbols and the RO. - the reception of the PDSCH is determined based on whether the PDSCH has been scheduled by downlink control information (DCI) or a higher layer.

19. The method according to claim 18, wherein, in the following cases (a) the RO is present on the UL subband, (b) the RO is effective, (c) The physical downlink shared channel (PDSCH) scheduled for the user equipment overlaps in the time domain with at least one of the N gap symbols and the RO, and (d) the PDSCH is scheduled by the DCI, - the PDSCH is normally received, and - PRACH transmission is not allowed in the RO.

20. The method according to claim 8, wherein, in the following cases (a) the RO is present on the UL subband, (b) the RO is effective, (c) The PDSCH scheduled for the user equipment overlaps at least one of the N gap symbols and the RO in the time domain, and (d) the PDSCH is scheduled by the higher layer, - the PDSCH is rate-matched and received based on resources overlapping in such a manner in the time domain, and - PRACH transmission is allowed in the RO.

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