Method performed by apparatus, apparatus, processing device and storage medium, and method performed by base station and base station

Abstract

This apparatus may: receive a synchronization signal block (SSB) on a cell at a first period; transmit an uplink channel for an SSB period change request for the cell; receive a response to the uplink channel; determine a second time point on the basis of a first time point at which the response is received; and receive, on the cell, the SSB at a second period different from the first period during a time interval starting at the second time point.

Description

Methods performed by devices, devices, processing devices and storage media, and methods performed by base stations and base stations

[0001] This specification relates to wireless communication systems.

[0002] Various devices and technologies, such as machine-to-machine (M2M) communication, machine-type communication (MTC), and smartphones and tablet PCs (personal computers) that require high data transmission rates, are emerging and becoming widespread. Consequently, the amount of data required to be processed on cellular networks is rapidly increasing. To meet this rapidly increasing data processing demand, technologies such as carrier aggregation and cognitive radio are being developed to efficiently utilize more frequency bands, while multi-antenna technology and multi-BS cooperation technology are being developed to increase the data capacity transmitted within a limited frequency range.

[0003] As more and more communication devices demand greater capacity, the need for enhanced mobile broadband (eMBB) communications is emerging, surpassing legacy radio access technology (RAT). Furthermore, massive machine type communication (mMTC), which connects multiple devices and objects to provide diverse services anytime, anywhere, is a key issue to be considered in next-generation communications.

[0004] Additionally, discussions are underway on communication systems designed to accommodate reliability- and latency-sensitive services and user equipment (UE). The introduction of next-generation wireless access technologies is being discussed, including enhanced mobile broadband (eMBB), mMTC, and ultra-reliable and low latency communication (URLLC).

[0005] As the number of services / UEs that a network must support rapidly increases, the need for energy conservation in the network as well as power conservation in the UE is also gradually increasing.

[0006] One technical task of this specification is to provide methods and processes for network energy conservation.

[0007] Another technical challenge of this specification is to provide methods and processes for transmitting downlink signals so as to enable network energy conservation.

[0008] The technical tasks to be achieved by this specification are not limited to the technical tasks mentioned above, and other technical tasks not mentioned will be clearly understood by those of ordinary skill in the art related to this specification from the detailed description below.

[0009] In one aspect of the present disclosure, a method by a device is provided. In another aspect of the present disclosure, a device is provided, comprising: at least one transceiver; at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations. In another aspect of the present disclosure, a processing device is provided, comprising: at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations. In another aspect of the present disclosure, a computer-readable, non-transitory storage medium is provided, storing at least one program code comprising instructions that, when executed, cause the at least one processor to perform operations. The method or the operations include: receiving a synchronization signal block (SSB) in a first period on a cell; transmitting an uplink channel for an SSB period change request for the cell; The method may include receiving a response to the uplink channel; determining a second time point based on a first time point at which the response is received; and receiving the SSB on the cell in a second period different from the first period during a time interval at the second time point.

[0010] In one aspect of the present disclosure, a method by a base station is provided. In another aspect of the present disclosure, a base station is provided, comprising: at least one transceiver; at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations. The method or the operations may include: receiving a synchronization signal block (SSB) in a first period on a cell; transmitting an uplink channel for an SSB period change request for the cell; receiving a response to the uplink channel; determining a second time point based on a first time point at which the response is received; and transmitting the SSB in a second period different from the first period during a time period at the second time point.

[0011] In each aspect of this specification, the uplink channel may be a random access channel.

[0012] In each aspect of this specification, the response may be a random access response to the random access channel.

[0013] In each aspect of this specification, a point in time after a predetermined offset after the first point in time can be determined to be the second point in time.

[0014] In each aspect of this specification, the method or the operations may include: receiving or transmitting information regarding the predetermined offset.

[0015] In each aspect of this specification, the method or the operations may include: receiving information regarding the duration of the time interval.

[0016] The above problem solving methods are only some of the examples of this specification, and various examples reflecting the technical features of this specification can be derived and understood by a person having ordinary knowledge in the relevant technical field based on the detailed description below.

[0017] According to some implementations of this specification, methods and procedures for energy saving of a network, BS and / or UE may be provided.

[0018] According to some implementations of this specification, methods and procedures for transmitting downlink signals to enable energy conservation of a network, a BS and / or a UE may be provided.

[0019] The effects according to this specification are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art related to this specification from the detailed description below.

[0020] To aid in understanding implementations of this specification, the accompanying drawings, which are included as part of the detailed description, provide examples of implementations of this specification and, together with the detailed description, illustrate implementations of this specification:

[0021] Figure 1 illustrates an example of a communication system 1 to which implementations of the present specification are applied;

[0022] FIG. 2 is a block diagram illustrating examples of communication devices capable of performing a method according to the present specification;

[0023] FIG. 3 illustrates another example of a wireless device capable of performing implementation(s) of the present specification;

[0024] FIG. 4 illustrates an example of a frame structure available in a 3rd generation partnership project (3GPP) based wireless communication system;

[0025] Figure 5 illustrates a resource grid of slots;

[0026] FIG. 6 illustrates physical channels used in a 3rd generation partnership project (3GPP)-based communication system, which is an example of a wireless communication system, and a signal transmission / reception process using the channels;

[0027] Figure 7 illustrates synchronization signal (SS) / physical broadcast channel (PBCH) blocks (SSBs) on a cell.

[0028] Figure 8 is a diagram illustrating the bitmaps used to indicate which SSBs are actually transmitted;

[0029] Figure 9 illustrates a process for acquiring system information (SI);

[0030] Figure 10 illustrates a random access process that may be applied to implementation(s) of this specification;

[0031] FIG. 11 illustrates an example of time domain resource allocation of a physical downlink shared channel (PDSCH) by a physical downlink control channel (PDCCH) and an example of time domain resource allocation of a physical uplink shared channel (PUSCH) by a PDCCH;

[0032] Figure 12 illustrates discontinuous reception (DRX) operation;

[0033] Figure 13 illustrates a case where a Long DRX cycle and a Short DRX cycle are set;

[0034] Figure 14 illustrates an operation procedure in a BS supporting network energy saving (NES) technology;

[0035] FIG. 15 is an example of a procedure for carrier aggregation (CA) operation using an SSB-less secondary cell (SCell);

[0036] Figures 16 to 18 illustrate on-demand SIB1 transmission scenarios related to some implementations of the present specification;

[0037] FIG. 19 is an example of random access channel (RACH) slots and RACH occasions (RO) according to physical random access channel (PRACH) settings;

[0038] Figures 20 and 21 illustrate the regulation of ROs according to some implementations of the present specification;

[0039] Figure 22 illustrates an association interval according to the number of SSBs per RACH period;

[0040] Figure 23 illustrates an associated interval considering a valid RACH period;

[0041] Figure 24 illustrates an association pattern section and SSB-to-RO mapping considering a valid RACH occasion (RO);

[0042] FIG. 25 illustrates a flow of downlink (DL) signal reception in a UE according to some implementations of the present specification;

[0043] Figure 26 illustrates the flow of downlink (DL) signal transmission in a BS according to some implementations of the present specification.

[0044] Hereinafter, implementations according to this specification will be described in detail with reference to the attached drawings. The detailed description provided below, together with the attached drawings, is intended to describe exemplary implementations of this specification and is not intended to represent the only possible implementations of this specification. The detailed description below includes specific details to provide a thorough understanding of this specification. However, one of ordinary skill in the art will appreciate that this specification may be practiced without these specific details.

[0045] In some cases, to avoid ambiguity in the concepts of this specification, known structures and devices may be omitted or illustrated in block diagram form focusing on the core functions of each structure and device. Furthermore, identical components are described using the same drawing reference numerals throughout this specification.

[0046] In this specification, "A or B" can mean "only A", "only B", or "both A and B". In other words, in this specification, "A or B" can be interpreted as "A and / or B". For example, in this specification, "A, B or C" can mean "only A", "only B", "only C", or "any combination of A, B and C".

[0047] The slash ( / ) or comma used in this specification can mean "and / or." For example, "A / B" can mean "A and / or B." Accordingly, "A / B" can mean "only A," "only B," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0048] In this specification, "at least one of A and B" may mean "only A", "only B" or "both A and B". Additionally, in this specification, the expressions "at least one of A or B" or "at least one of A and / or B" may be interpreted identically to "at least one of A and B".

[0049] Additionally, in this specification, “at least one of A, B and C” can mean “only A”, “only B”, “only C”, or “any combination of A, B and C”. Additionally, “at least one of A, B or C” or “at least one of A, B and / or C” can mean “at least one of A, B and C”.

[0050] Additionally, in this specification, terms such as “first,” “second,” etc. are used only to distinguish one component from another and are not used to limit the components, and do not limit the order or importance between the components unless specifically limited. Accordingly, a first component in one embodiment of this specification may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0051] In the following explanation, ‘when, if, in case of’ can be replaced with ‘based on’.

[0052] In this specification, "configured or pre-configured" information / state / parameters can be interpreted as information / state / parameters being provided / pre-provided to the UE through pre-defined signaling from the BS (e.g., system information block (SIB), medium access control (MAC), radio resource control (RRC)). In this specification, "defined or pre-defined" information / state / parameters can be interpreted as information that the BS and the UE know in advance or pre-store without signaling between the BS and the UE.

[0053] Technical features individually described within a single drawing in this specification may be implemented individually or simultaneously.

[0054] The techniques, devices, and systems described below can be applied to various wireless multiple access systems. Examples of multiple access systems include code division multiple access (CDMA) systems, frequency division multiple access (FDMA) systems, time division multiple access (TDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and multi-carrier frequency division multiple access (MC-FDMA) systems. CDMA can be implemented in wireless technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented in wireless technologies such as Global System for Mobile communication (GSM), General Packet Radio Service (GPRS), and Enhanced Data Rates for GSM Evolution (EDGE) (i.e., GERAN). OFDMA can be implemented in wireless technologies such as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (WiFi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (evolved-UTRA). UTRA is part of UMTS (Universal Mobile Telecommunication System), and 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) is a part of E-UMTS that uses E-UTRA.3GPP LTE adopts OFDMA for the downlink (DL) and SC-FDMA for the uplink (UL). LTE-A (LTE-advanced) is an evolved form of 3GPP LTE.

[0055] For convenience of explanation, the following description assumes that this specification applies to 3GPP-based communication systems, such as LTE and NR. However, the technical features of this specification are not limited to this. For example, although the detailed description below is based on a mobile communication system corresponding to a 3GPP LTE / NR system, it can also be applied to any other mobile communication system, except for features specific to 3GPP LTE / NR.

[0056] For terms and technologies used in this specification that are not specifically explained, reference may be made to 3GPP-based standard documents, such as 3GPP TS 36.211, 3GPP TS 36.212, 3GPP TS 36.213, 3GPP TS 36.321, 3GPP TS 36.300 and 3GPP TS 36.331, 3GPP TS 37.213, 3GPP TS 38.211, 3GPP TS 38.212, 3GPP TS 38.213, 3GPP TS 38.214, 3GPP TS 38.300, 3GPP TS 38.304, 3GPP TS 38.331, etc.

[0057] In the examples of this specification described below, the expression "assumes" that a device "assumes" that the entity transmitting the channel transmits the channel in a manner consistent with the "assume." The entity receiving the channel may mean that, under the assumption that the channel was transmitted in a manner consistent with the "assume," the entity receiving the channel receives or decodes the channel in a manner consistent with the "assume."

[0058] In this specification, UE may be fixed or mobile, and includes various devices that communicate with a BS (base station) to transmit and / or receive user data and / or various control information. UE may be called (Terminal Equipment), MS (Mobile Station), MT (Mobile Terminal), UT (User Terminal), SS (Subscribe Station), wireless device, PDA (Personal Digital Assistant), wireless modem, handheld device, etc. In addition, in this specification, BS generally refers to a fixed station that communicates with UE and / or other BS, and exchanges various data and control information with UE and other BS. BS may be called by other terms such as ABS (Advanced Base Station), NB (Node-B), eNB (evolved-NodeB), BTS (Base Transceiver System), Access Point, PS (Processing Server), etc. In particular, the BS in UTRAN is called a Node-B, the BS in E-UTRAN is called an eNB, and the BS in a new radio access technology network is called a gNB. For convenience of explanation, BSs are collectively referred to as BSs below, regardless of the type or version of communication technology.

[0059] In this specification, a node refers to a fixed point that can transmit / receive radio signals by communicating with a UE. Various types of BSs can be used as nodes regardless of their names. For example, BSs, NBs, eNBs, pico-cell eNBs (PeNBs), home eNBs (HeNBs), relays, and repeaters can be nodes. Furthermore, a node may not be a BS. For example, it can be a radio remote head (RRH) or a radio remote unit (RRU). RRHs, RRUs, etc. generally have a lower power level than the BS. Since an RRH or RRU (hereinafter referred to as RRH / RRU) is generally connected to a BS via a dedicated line such as an optical cable, cooperative communication between an RRH / RRU and a BS can be performed more smoothly than cooperative communication between BSs that are generally connected via a wireless line. Each node is equipped with at least one antenna. The antenna may be a physical antenna, an antenna port, a virtual antenna, or an antenna group. A node is also called a point.

[0060] In this specification, a cell refers to a certain geographical area where one or more nodes provide communication services. Therefore, in this specification, communicating with a specific cell may mean communicating with a BS or node that provides communication services to the specific cell. In addition, the downlink / uplink signal of a specific cell refers to a downlink / uplink signal from / to a BS or node that provides communication services to the specific cell. A cell that provides uplink / downlink communication services to a UE is specifically referred to as a serving cell. In addition, the channel state / quality of a specific cell refers to the channel state / quality of a channel or communication link formed between a BS or node that provides communication services to the specific cell and the UE. In a 3GPP-based communication system, a UE can measure a downlink channel state from a specific node using CRS (Cell-specific Reference Signal) resources transmitted by antenna port(s) of the specific node on CRS resources allocated to the specific node and / or CSI-RS (Channel State Information Reference Signal) resources transmitted.

[0061] Meanwhile, 3GPP-based communication systems use the concept of cells to manage radio resources, and cells associated with radio resources are distinguished from cells in geographical areas.

[0062] A "cell" in a geographical area can be understood as the coverage over which a node can provide a service using a carrier, and a "cell" in a radio resource is associated with a bandwidth (BW), which is a frequency range configured by the carrier. Since downlink coverage, which is the range over which a node can transmit a valid signal, and uplink coverage, which is the range over which a node can receive a valid signal from a UE, depend on the carrier carrying the signal, the coverage of a node is also associated with the coverage of the "cell" of the radio resource used by the node. Therefore, the term "cell" can sometimes be used to mean the coverage of a service provided by a node, sometimes a radio resource, and sometimes the range over which a signal using the radio resource can reach with a valid intensity.

[0063] Meanwhile, the 3GPP communication standard uses the concept of a cell to manage radio resources. A "cell" associated with radio resources is defined as a combination of downlink resources (DL resources) and uplink resources (UL resources), i.e., a combination of a DL component carrier (CC) and an UL CC. A cell can be configured with DL resources alone or a combination of DL resources and UL resources. If carrier aggregation is supported, the linkage 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. For example, the combination of DL resources and UL resources can be indicated by a System Information Block Type 2 (SIB2) linkage. Here, the carrier frequency can be the same as or different from the center frequency of each cell or CC. When carrier aggregation (CA) is established, the UE has only one radio resource control (RRC) connection with the network. One serving cell provides non-access stratum (NAS) mobility information during RRC connection establishment / re-establishment / handover, and one serving cell provides security input during RRC connection re-establishment / handover. Such a cell is called a primary cell (Pcell). A Pcell is a cell operating on the primary frequency where the UE performs initial connection establishment procedures or initiates connection re-establishment procedures.Depending on the UE capability, secondary cells (Scells) can be configured to form a set of serving cells together with Pcells. An Scell ​​can be configured after an RRC (Radio Resource Control) connection establishment has been made, and is a cell that provides additional radio resources in addition to the resources of a special cell (SpCell). The carrier corresponding to a Pcell in downlink is called a downlink primary CC (DL PCC), and the carrier corresponding to a Pcell in uplink is called an UL primary CC (UL PCC). The carrier corresponding to an Scell ​​in downlink is called a DL secondary CC (DL SCC), and the carrier corresponding to the Scell ​​in uplink is called an UL secondary CC (UL SCC).

[0064] For a UE for which CA is set and DC is not set, a Pcell PUCCH group (also referred to as a primary PUCCH group) consisting of a Pcell and zero or more Scells and a Scell ​​PUCCH group (also referred to as a secondary PUCCH group) consisting of only Scell(s) may be set. In the case of an Scell, an Scell ​​(hereinafter referred to as a PUCCH Scell) on which a PUCCH associated with the cell is transmitted may be set. An Scell ​​for which a PUCCH Scell ​​is indicated belongs to an Scell ​​PUCCH group (i.e., a secondary PUCCH group), and PUCCH transmission of the relevant UCI is performed on the PUCCH Scell, and an Scell ​​for which a PUCCH Scell ​​is not indicated or which is a Pcell and is indicated as a cell for PUCCH transmission belongs to a Pcell PUCCH group (i.e., a primary PUCCH group), and PUCCH transmission of the relevant UCI is performed on the Pcell. Hereinafter, if a UE is configured with an SCG and some implementations of this specification related to PUCCH are applied to the SCG, the primary cell may refer to a PSCell of the SCG. If a UE is configured with a PUCCH Scell ​​and some implementations of this specification related to PUCCH are applied to a secondary PUCCH group, the primary cell may refer to a PUCCH Scell ​​of the secondary PUCCH group.

[0065] In a wireless communication system, a UE receives information from a base station (BS) via the downlink (DL), and the UE transmits information to the base station via the uplink (UL). The information transmitted and / or received by the BS and UE includes data and various control information, and various physical channels exist depending on the type and purpose of the information they transmit and / or receive.

[0066] 3GPP-based communication standards define downlink physical channels corresponding to resource elements that carry information originating from higher layers, and downlink physical signals corresponding to resource elements that are used by the physical layer but do not carry information originating from higher layers. For example, the physical downlink shared channel (PDSCH), physical broadcast channel (PBCH), and physical downlink control channel (PDCCH) are defined as downlink physical channels, and reference signals and synchronization signals are defined as downlink physical signals. A reference signal (RS), also referred to as a pilot, refers to a signal with a predefined, special waveform that is known to the BS and the UE. For example, the demodulation reference signal (DMRS), the channel state information RS (CSI-RS), and the positioning reference signal (PRS) are defined as downlink reference signals. 3GPP-based communication standards define uplink physical channels corresponding to resource elements that carry information originating from higher layers, and uplink physical signals corresponding to resource elements that are used by the physical layer but do not carry information originating from higher layers.For example, a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), and a physical random access channel (PRACH) are defined as uplink physical channels, and a demodulation reference signal (DMRS) for uplink control / data signals and a sounding reference signal (SRS) used for uplink channel measurement are defined.

[0067] In this specification, PDCCH (Physical Downlink Control CHannel) refers to a set of time-frequency resources (e.g., resource elements (REs)) that carry DCI (Downlink Control Information), and PDSCH (Physical Downlink Shared CHannel) refers to a set of time-frequency resources that carry downlink data. In addition, PUCCH (Physical Uplink Control CHannel), PUSCH (Physical Uplink Shared CHannel), and PRACH (Physical Random Access CHannel) refer to sets of time-frequency resources that carry UCI (Uplink Control Information), uplink data, and random access signals, respectively (respectively). Hereinafter, the expression that a user equipment transmits / receives a PUCCH / PUSCH / PRACH is used with the same meaning as that uplink control information / uplink data / random access signals are transmitted / received on or through the PUCCH / PUSCH / PRACH, respectively. Additionally, the expression that BS transmits / receives PBCH / PDCCH / PDSCH is used with the same meaning as transmitting broadcast information / downlink control information / downlink data on or through PBCH / PDCCH / PDSCH, respectively.

[0068] In this specification, radio resources (e.g., time-frequency resources) scheduled or configured by the BS to the UE for transmission or reception of PUCCH / PUSCH / PDSCH are also referred to as PUCCH / PUSCH / PDSCH resources.

[0069] Since the communication device receives a synchronization signal (SS), DMRS, CSI-RS, PRS, PBCH, PDCCH, PDSCH, PUSCH, and / or PUCCH in the form of radio signals on a cell, it cannot selectively receive through an RF receiver only radio signals including only a specific physical channel or only a specific physical signal, or selectively receive through an RF receiver only radio signals excluding only a specific physical channel or only a physical signal. In actual operation, the communication device first receives radio signals on a cell through an RF receiver, converts the radio signals, which are RF band signals, into baseband signals, and decodes a physical signal and / or a physical channel within the baseband signals using one or more processors. Thus, in some implementations of the present specification, not receiving a physical signal and / or a physical channel may not actually mean that the communication device does not receive wireless signals containing the physical signal and / or physical channel at all, but rather that it does not attempt to recover the physical signal and / or physical channel from the wireless signals, e.g., does not attempt to decode the physical signal and / or the physical channel.

[0070] As more and more communication devices demand greater communication capacity, the need for improved mobile broadband communication compared to existing radio access technology (RAT) is emerging. Furthermore, massive MTC, which connects numerous devices and objects to provide diverse services anytime, anywhere, is also a key issue to be considered in next-generation communications. Furthermore, communication system design that considers reliability and latency-sensitive services / UEs is being discussed. The introduction of next-generation RATs that take advanced mobile broadband communication, massive MTC, and URLLC (Ultra-Reliable and Low Latency Communication) into account is currently under discussion. 3GPP is currently conducting studies on next-generation mobile communication systems beyond EPC. For convenience, this technology is referred to as new RAT (NR) or 5G RAT, and a system that uses or supports NR is referred to as an NR system.

[0071] FIG. 1 illustrates an example of a communication system 1 to which implementations of the present specification are applied. Referring to FIG. 1, the communication system (1) applied to the present specification includes a wireless device, a BS, and a network. Here, the wireless device refers to a device that performs communication using a wireless access technology (e.g., 5G NR (New RAT), LTE (e.g., E-UTRA)) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (eXtended Reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Things) device (100f), and an AI device / server (400). For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing vehicle-to-vehicle communication, etc. Here, the vehicle may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). XR devices include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices, and may be implemented in the form of a Head-Mounted Device (HMD), a Head-Up Display (HUD) installed in a vehicle, a television, a smartphone, a computer, a wearable device, a home appliance, digital signage, a vehicle, a robot, etc. Mobile devices may include a smartphone, a smart pad, a wearable device (e.g., a smart watch, smart glasses), a computer (e.g., a laptop, etc.), etc. Home appliances may include a TV, a refrigerator, a washing machine, etc. IoT devices may include sensors, smart meters, etc. For example, a BS or network may also be implemented as a wireless device, and a specific wireless device may act as a BS / network node to other wireless devices.

[0072] Wireless devices (100a to 100f) can be connected to a network (300) via a BS (200). Artificial Intelligence (AI) technology can be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (400) via a network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, etc. The wireless devices (100a to 100f) can communicate with each other via the BS (200) / network (300), but can also communicate directly (e.g., sidelink communication) without going through the BS / network. For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (Vehicle to Vehicle) / V2X (Vehicle to Everything) communication). In addition, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0073] Wireless communication / connection (150a, 150b) can be performed between wireless devices (100a~100f) / BS (200) - BS (200) / wireless devices (100a~100f). Here, the wireless communication / connection can be performed through various wireless access technologies (e.g., 5G NR) for uplink / downlink communication (150a) and sidelink communication (150b) (or D2D communication). Through the wireless communication / connection (150a, 150b), the wireless device and the BS / wireless device can transmit / receive wireless signals to / from each other. To this end, at least some of various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), and resource allocation processes can be performed based on various proposals of this specification.

[0074] FIG. 2 is a block diagram illustrating examples of communication devices capable of performing a method according to the present specification. Referring to FIG. 2, a first wireless device (100) and a second wireless device (200) can transmit and / or receive wireless signals via various wireless access technologies (e.g., LTE, NR). Here, {the first wireless device (100), the second wireless device (200)} can correspond to {the wireless device (100x), the BS (200)} and / or {the wireless device (100x), the wireless device (100x)} of FIG. 1.

[0075] A first wireless device (100) includes one or more processors (102) and one or more memories (104), and may further include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memories (104) and / or the transceivers (106), and may be configured to implement functions, procedures, and / or methods described / suggested below. For example, the processor (102) may process information in the memory (104) to generate first information / signals, and then transmit a wireless signal including the first information / signals via the transceivers (106). In addition, the processor (102) may receive a wireless signal including second information / signals via the transceivers (106), and then store information obtained from signal processing of the second information / signals in the memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may perform some or all of the processes controlled by the processor (102), or may store software code including commands for performing the procedures and / or methods described / proposed below. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals via one or more antennas (108). The transceiver (106) may include a transmitter and / or a receiver. The transceiver (106) may be used interchangeably with an RF (Radio Frequency) unit. In this specification, a wireless device may also mean a communication modem / circuit / chip.

[0076] The second wireless device (200) includes one or more processors (202), one or more memories (204), and may further include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memories (204) and / or the transceivers (206), and may be configured to implement the functions, procedures, and / or methods described / suggested below. For example, the processor (202) may process information in the memory (204) to generate third information / signals, and then transmit a wireless signal including the third information / signals via the transceivers (206). In addition, the processor (202) may receive a wireless signal including fourth information / signals via the transceivers (206), and then store information obtained from signal processing of the fourth information / signals in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may perform some or all of the processes controlled by the processor (202), or may store software code including commands for performing the procedures and / or methods described / proposed below. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement wireless communication technology (e.g., LTE, NR). The transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals via one or more antennas (208). The transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with an RF unit. In this specification, a wireless device may also mean a communication modem / circuit / chip.

[0077] The wireless communication technology implemented in the wireless device (100, 200) of the present specification may include not only LTE, NR, and 6G, but also Narrowband Internet of Things for low-power communication. At this time, for example, NB-IoT technology may be an example of LPWAN (Low Power Wide Area Network) technology, and may be implemented with standards such as LTE Cat NB1 and / or LTE Cat NB2, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device (XXX, YYY) of the present specification may perform communication based on LTE-M technology. At this time, for example, LTE-M technology may be an example of LPWAN technology, and may be called by various names such as eMTC (enhanced Machine Type Communication). For example, LTE-M technology can be implemented by at least one of various standards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-BL (non-Bandwidth Limited), 5) LTE-MTC, 6) LTE Machine Type Communication, and / or 7) LTE M, and is not limited to the above-described names. Additionally or alternatively, the wireless communication technology implemented in the wireless device (XXX, YYY) of the present specification can include at least one of ZigBee, Bluetooth, and Low Power Wide Area Network (LPWAN) considering low-power communication, and is not limited to the above-described names. For example, ZigBee technology can create personal area networks (PAN) related to small / low-power digital communication based on various standards such as IEEE 802.15.4, and can be called by various names.

[0078] Hereinafter, hardware elements of the wireless device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, a radio resource control (RRC) layer, and a service data adaptation protocol (SDAP) layer). One or more processors (102, 202) may generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the functions, procedures, proposals, and / or methods disclosed in this specification. One or more processors (102, 202) may generate messages, control information, data or information according to the functions, procedures, proposals and / or methods disclosed in this specification. One or more processors (102, 202) may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and / or methods disclosed in this specification, and provide the signals to one or more transceivers (106, 206). One or more processors (102, 202) may receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and / or methods disclosed in this specification.

[0079] One or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). The functions, procedures, proposals, and / or methods disclosed in this specification may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to perform the functions, procedures, suggestions and / or methods disclosed in this specification may be included in one or more processors (102, 202) or stored in one or more memories (104, 204) and executed by one or more processors (102, 202). The functions, procedures, suggestions and / or methods disclosed in this specification may be implemented using firmware or software in the form of codes, instructions and / or sets of instructions.

[0080] One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories (104, 204) may be configured as ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer-readable storage media, and / or combinations thereof. The one or more memories (104, 204) may be located internally and / or externally to the one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to the one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0081] One or more transceivers (106, 206) may transmit user data, control information, wireless signals / channels, etc., as described in the methods and / or flowcharts of this specification, to one or more other devices. One or more transceivers (106, 206) may receive user data, control information, wireless signals / channels, etc., as described in the functions, procedures, proposals, methods and / or flowcharts of this specification, from one or more other devices. For example, one or more transceivers (106, 206) may be coupled to one or more processors (102, 202) and may transmit and / or receive wireless signals. For example, one or more processors (102, 202) may control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be coupled to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and / or receive user data, control information, wireless signals / channels, or the like, as referred to in the functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this specification, via one or more antennas (108, 208). In this specification, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) may convert received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals for processing using one or more processors (102, 202).One or more transceivers (106, 206) may convert user data, control information, wireless signals / channels, etc. processed by one or more processors (102, 202) from baseband signals to RF band signals. For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or filter.

[0082] FIG. 3 illustrates another example of a wireless device capable of performing implementation(s) of the present specification. Referring to FIG. 3, the wireless device (100, 200) corresponds to the wireless device (100, 200) of FIG. 2 and may be composed of various elements, components, units / units, and / or modules. For example, the wireless device (100, 200) may include a communication unit (110), a control unit (120), a memory unit (130), and additional elements (140). The communication unit may include a communication circuit (112) and a transceiver(s) (114). For example, the communication circuit (112) may include one or more processors (102, 202) and / or one or more memories (104, 204) of FIG. 2. For example, the transceiver(s) (114) may include one or more transceivers (106, 206) and / or one or more antennas (108, 208) of FIG. 2. The control unit (120) is electrically connected to the communication unit (110), the memory unit (130), and the additional elements (140) and controls the overall operation of the wireless device. For example, the control unit (120) may control the electrical / mechanical operation of the wireless device based on the program / code / command / information stored in the memory unit (130). In addition, the control unit (120) may transmit information stored in the memory unit (130) to an external device (e.g., another communication device) via a wireless / wired interface through the communication unit (110), or store information received from an external device (e.g., another communication device) via a wireless / wired interface in the memory unit (130).

[0083] The additional element (140) may be configured in various ways depending on the type of the wireless device. For example, the additional element (140) may include at least one of a power unit / battery, an input / output (I / O) unit, a driving unit, and a computing unit. Although not limited thereto, the wireless device may be implemented in the form of a robot (Fig. 1, 100a), a vehicle (Fig. 1, 100b-1, 100b-2), an XR device (Fig. 1, 100c), a portable device (Fig. 1, 100d), a home appliance (Fig. 1, 100e), an IoT device (Fig. 1, 100f), a UE for digital broadcasting, a hologram device, a public safety device, an MTC device, a medical device, a fintech device (or a financial device), a security device, a climate / environmental device, an AI server / device (Fig. 1, 400), a BS (Fig. 1, 200), a network node, etc. Wireless devices may be mobile or stationary depending on the use / service.

[0084] In FIG. 3, various elements, components, units / parts, and / or modules within the wireless device (100, 200) may be entirely interconnected via a wired interface, or at least some may be wirelessly connected via a communication unit (110). For example, within the wireless device (100, 200), the control unit (120) and the communication unit (110) may be wired, and the control unit (120) and a first unit (e.g., 130, 140) may be wirelessly connected via the communication unit (110). In addition, each element, component, unit / part, and / or module within the wireless device (100, 200) may further include one or more elements. For example, the control unit (120) may be composed of one or more processor sets. For example, the control unit (120) may be composed of a set of a communication control processor, an application processor, an electronic control unit (ECU), a graphics processing processor, a memory control processor, etc. As another example, the memory unit (130) may be composed of RAM (Random Access Memory), DRAM (Dynamic RAM), ROM (Read Only Memory), flash memory, transitory memory, non-transitory memory, and / or a combination thereof.

[0085] In this specification, at least one memory (e.g., 104 or 204) can store instructions or programs that, when executed, cause at least one processor operably connected to the at least one memory to perform operations according to some embodiments or implementations of the present specification.

[0086] In this specification, a computer-readable (non-transitory) storage medium can store at least one instruction or computer program, which when executed by at least one processor causes the at least one processor to perform operations according to some embodiments or implementations of this specification.

[0087] In this specification, a processing device or apparatus may include at least one processor and at least one computer memory operatively connected to the at least one processor. The at least one computer memory may store instructions or programs, which, when executed, cause at least one processor operatively connected to the at least one memory to perform operations according to some embodiments or implementations of the present specification.

[0088] In this specification, a computer program may be stored in at least one computer-readable (non-transitory) storage medium and may include program code that, when executed, performs operations according to some implementations of the present specification or causes at least one processor to perform operations according to some implementations of the present specification. The computer program may be provided in the form of a computer program product. The computer program product may include at least one computer-readable (non-transitory) storage medium.

[0089] A communications device of the present specification comprises at least one processor; and at least one computer memory operably connected to said at least one processor and storing instructions that, when executed, cause said at least one processor to perform operations according to the example(s) of the present specification described below.

[0090] Figure 4 illustrates an example of a frame structure available in a 3GPP-based wireless communication system.

[0091] The structure of the frame in Fig. 4 is merely an example, and the number of subframes, the number of slots, and the number of symbols in the frame can be varied. In an NR system, OFDM numerology (e.g., subcarrier spacing (SCS)) may be set differently between multiple cells aggregated to a single UE. Accordingly, the (absolute time) duration of a time resource (e.g., a subframe, a slot, or a transmission time interval (TTI)) consisting of the same number of symbols may be set differently between the aggregated cells. Here, the symbol may include an OFDM symbol (or a cyclic prefix - orthogonal frequency division multiplexing (CP-OFDM) symbol), an SC-FDMA symbol (or a discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbol). In this specification, the terms symbol, OFDM-based symbol, OFDM symbol, CP-OFDM symbol, and DFT-s-OFDM symbols are interchangeable.

[0092] Referring to Figure 4, in the NR system, uplink and downlink transmissions are organized into frames. Each frame is T f = (△f max *N f / 100)*T c = 10 ms duration, divided into two half-frames of 5 ms each. Here, T is the basic time unit for NR. c = 1 / (△fmax *N f ) and △f max = 480*10 3 Hz, and N f =4096. For reference, T is the basic time unit for LTE. s = 1 / (△f ref *N f,ref ) and △f ref = 15*10 3 Hz, and N f,ref =2048. T s Wow T c is a constant κ = T s / T c = 64 relationship. Each half-frame consists of 5 subframes, and the duration of a single subframe is T. sf is 1ms. Subframes are further divided into slots, and the number of slots in a subframe depends on the subcarrier spacing. Each slot consists of 14 or 12 OFDM symbols based on the cyclic prefix. For a normal cyclic prefix (CP), each slot consists of 14 OFDM symbols, and for an extended CP, each slot consists of 12 OFDM symbols. The numerology is exponentially scalable with a subcarrier spacing △f = 2. u *Depends on 15 kHz. The following table shows the subcarrier spacing for regular CP △f = 2. u *Number of OFDM symbols per slot at 15 kHz (N) slot symb ), number of slots per frame (N frame,u slot ) and the number of slots per subframe (N subframe,u slot ) is shown.

[0093]

[0094] The following table shows the subcarrier spacing for extended CP △f = 2. u*Indicates the number of OFDM symbols per slot, the number of slots per frame, and the number of slots per subframe at 15 kHz.

[0095]

[0096] For a subcarrier spacing setting u, slots are n in increasing order within a subframe. u s ∈ {0, ..., nsubframe,u slot - 1} and n in increasing order within the frame u s,f ∈ {0, ..., n frame,u slot - Numbered as 1}.

[0097] Figure 5 illustrates the resource grid of a slot. A slot contains multiple symbols (e.g., 14 or 12) in the time domain. For each numeral (e.g., subcarrier spacing) and carrier, a common resource block (CRB) N is indicated by higher layer signaling (e.g., radio resource control (RRC) signaling). start,u grid Starting from,N size,u grid,x *N RB sc Dog subcarriers and N subframe,u symb A resource grid of OFDM symbols is defined, where N size,u grid,x is the number of resource blocks (RBs) in the resource grid, and the subscript x is DL for downlink and UL for uplink. N RB sc is the number of subcarriers per RB, and in 3GPP-based wireless communication systems, N RB scis typically 12. For a given antenna port p, subcarrier spacing configuration u, and transmission direction (DL or UL), there is one resource grid. The carrier bandwidth N for subcarrier spacing configuration u size,u grid is given to the UE by higher layer parameters (e.g., RRC parameters) from the network. Each element in the resource grid for antenna port p and subcarrier spacing configuration u is called a resource element (RE), and one complex symbol can be mapped to each RE. Each RE in the resource grid is uniquely identified by an index k in the frequency domain and an index l indicating the symbol position relative to a reference point in the time domain. In an NR system, an RB is defined by 12 consecutive subcarriers in the frequency domain. In an NR system, RBs can be classified into common resource blocks (CRBs) and physical resource blocks (PRBs). CRBs are numbered upwards from 0 in the frequency domain for the subcarrier spacing configuration u. The center of subcarrier 0 of CRB 0 for the subcarrier spacing configuration u coincides with 'Point A', which is a common reference point for the resource block grids. PRBs for subcarrier spacing u are defined within the bandwidth part (BWP) and range from 0 to N. size,u BWP,i -1, where i is the number of the bandwidth part. Common resource block n u CRB and bandwidth part i within physical resource block n PRB The relationship between the two is as follows: n u PRB = n u CRB +N start,u BWP,i , here N start,u BWP,iis a common resource block (BRB) whose bandwidth part starts relative to CRB 0. A BWP comprises multiple consecutive RBs in the frequency domain. For example, a BWP may be a given numeral u within a BWP i on a given carrier. i A subset of contiguous CRBs defined for a carrier. A carrier may include up to N (e.g., 5) BWPs. A UE may be configured to have one or more BWPs on a given component carrier. Data communication is performed through the activated BWPs, and only a predetermined number (e.g., 1) of BWPs configured for the UE may be activated on the carrier.

[0098] For each serving cell in a set of DL BWPs or UL BWPs, the network configures at least an initial DL BWP and one (if the serving configuration is configured with uplink) or two (if supplementary uplink is used) initial UL BWPs. The network may also configure additional UL and DL BWPs for the serving cell. For each DL BWP or UL BWP, the UE is provided with the following parameters for the serving cell: i) subcarrier spacing, ii) cyclic prefix, and iii) N start BWP = Offset RB with the assumption of 275 set and length L RB CRBN provided by the RRC parameter locationAndBandwidth, which indicates the resource indicator value (RIV). start BWP =O carrier +RB start and the number of contiguous RBs N size BWP =L RB , and the subcarrier spacing is provided by the RRC parameter offsetToCarrierO carrier; an index within the set of DL BWPs or UL BWPs; a set of BWP-common parameters and a set of BWP-specific parameters.

[0099] Switching between configured BWPs can occur using RRC signaling, DCI, an inactivity timer, or upon initiation of a random access. If an inactivity timer is configured for a serving cell, expiration of the inactivity timer associated with the serving cell switches the active BWP to the default BWP configured by the network.

[0100] Virtual resource blocks (VRBs) are defined within the bandwidth part and are numbered from 0 to N. size,u BWP,i Numbered from -1, where i is the number of the bandwidth part. VRBs are mapped to physical resource blocks (PRBs) according to interleaved or non-interleaved mapping. In some implementations, for non-interleaved VRB-to-PRB mapping, VRB n may be mapped to PRB n.

[0101] NR frequency bands are defined by two types of frequency ranges, FR1 and FR2, with FR2 also referred to as millimeter wave (mmW). The following table lists the frequency ranges in which NR can operate.

[0102]

[0103] Figure 6 illustrates physical channels used in a 3GPP-based communication system, which is an example of a wireless communication system, and a signal transmission / reception process using the channels.

[0104] When a UE is powered on again after being powered off or has been disconnected from a wireless communication system, it first searches for a suitable cell to camp on (search cell) and performs an initial cell search process, such as synchronizing with the cell or the BS of the cell (S11). During the initial cell search process, the UE receives a synchronization signal block (SSB) (also called an SSB / PBCH block) from the BS. The SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast channel (PBCH). The UE synchronizes with the BS based on the PSS / SSS and obtains information such as a cell identity (ID). In addition, the UE can obtain broadcast information within the cell based on the PBCH. Meanwhile, the UE can check the downlink channel status by receiving a downlink reference signal (DL RS) during the initial cell search process.

[0105] A UE that has completed initial cell search can camp on the cell. After camping on the cell, the UE monitors the PDCCH on the cell and receives the PDSCH based on the downlink control information (DCI) carried by the PDCCH to obtain more specific system information (S12).

[0106] Thereafter, the UE may perform a random access procedure to complete access to the BS (S13 to S16). For example, in the random access procedure, the UE may transmit a preamble through a physical random access channel (PRACH) (S13) and receive a random access response (RAR) to the preamble through a PDCCH and a corresponding PDSCH (S14). If reception of the RAR for the UE fails, the UE may retry transmitting the preamble. In the case of contention-based random access, a contention resolution procedure (S16) may be performed, including transmission of a PUSCH based on UL resource allocation included in the RAR (S15) and reception of a PDCCH and a corresponding PDSCH.

[0107] The UE, which has performed the procedure described above, can then perform reception of PDCCH / PDSCH (S17) and transmission of PUSCH / PUCCH (S18) as a general uplink / downlink signal transmission process. The control information that the UE transmits to the BS is collectively referred to as uplink control information (UCI). UCI includes HARQ ACK / NACK (Hybrid Automatic Repeat and reQuest Acknowledgement / Negative-ACK) (also referred to as HARQ-ACK), scheduling request (SR), channel state information (CSI), etc. CSI may include a channel quality indicator (CQI), a precoding matrix indicator (PMI), and / or a rank indicator. UCI is generally transmitted through PUCCH, but may be transmitted through PUSCH when control information and traffic data must be transmitted simultaneously. Additionally, based on a request / instruction from the network, the UE can transmit UCI aperiodically via PUSCH.

[0108] Figure 7 illustrates SS / PBCH blocks (SSBs) on a cell.

[0109] In 3GPP-based systems, each SSB is associated with a beam. For example, during a half-frame, different SSBs can be transmitted in different spatial directions (using different beams spanning the cell's coverage area). The possible temporal locations of SSBs within a half-frame are determined by the subcarriers, and the periodicity of the half-frames over which the SSBs are transmitted is set by the network. Multiple SSBs can be transmitted within the frequency span of a carrier. Different indices of SSBs transmitted / detected on a cell can correspond to different BS (wide) Tx beams. Multiple SSBs can be transmitted within the frequency span of a carrier. The physical (layer) cell identifiers (PCIs) of SSBs transmitted at different frequency locations need not be unique, and different SSBs in the frequency domain can have different PCIs. If an SSB is associated with a remaining minimum system information (RMSI), the SSB is referred to as a cell-defining SSB (CD-SSB), and the PCell is always associated with a CD-SSB located on the synchronization raster (sync raster). If an SSB is not associated with an RMSI, the SSB is referred to as a non-cell defining SSB (NCD-SSB), which can be used to perform RLM, BFD and RRM measurements, and measurements for random access resource selection within the active DL BWP if the active DL BWP does not include the CD-SSB.In 3GPP-based systems, multi-beam operation is based on beam switching / beam scanning, which transmits / receives signals while changing the beam direction over time. Beam sweeping means that a transmission and reception point (TRP) (e.g., a BS / cell) changes the beam (direction) of a wireless signal over time. In this specification, the terms beam and beam direction can be used interchangeably. SSBs can be transmitted periodically using beam sweeping. In this case, the SSB index is implicitly linked to the SSB beam. The SSB beam can be changed on an SSB (index) basis or on an SSB (index) group basis. In the latter case, the SSB beam remains the same within the SSB (index) group. For example, referring to Figure 7, the transmission beam direction of an SSB can be repeated for multiple consecutive SSBs. A set of SSBs is transmitted within a 5 ms half-frame. The set of bits transmitted within a 5 ms half-frame of an SSB transmission is called an SSB burst set. The maximum number of SSB transmissions within an SSB burst set is L. max has a value of 4, 8, or 64 depending on the frequency band to which the carrier belongs. For example, the maximum number of SSBs in an SSB burst set, L max can be given as follows.

[0110] - For frequency range up to 3 GHz, L max = 4

[0111] - For frequency range from 3GHz to 6 GHz, L max = 8

[0112] - For frequency range from 6 GHz to 52.6 GHz, L max = 64

[0113] The number of SSBs actually transmitted can be set, with a maximum number Lmax It can be smaller.

[0114] If multi-beam transmission is not applied, the number of SSB beams is 1.

[0115] Figure 8 is a diagram illustrating the bitmaps used to indicate which SSBs are actually transmitted.

[0116] Within an SSB burst set, up to L SSBs can be transmitted, and the number / positions of the SSBs actually transmitted may vary depending on the BS / cell. The number / positions of the SSBs actually transmitted are used for rate matching and measurement, and information about the SSBs actually transmitted (e.g., RRC configuration ssb-PositionsInBurst) can be indicated as follows.

[0117] - In case of rate-matching: It can be indicated via UE-specific RRC signaling or RMSI. The UE-specific RRC signaling includes a full (e.g., length L) bitmap in both the frequency ranges below 6 GHz and above 6 GHz. On the other hand, the remaining minimum system information (RMSI) (i.e., SIB1) includes a full bitmap below 6 GHz and a compressed bitmap above 6 GHz as illustrated. Specifically, information about actually transmitted SSB can be indicated using a group bitmap (8 bits) and an intra-group bitmap (8 bits). Here, resources (e.g., resource elements (REs)) indicated via the UE-specific RRC signaling or RMSI are reserved for SSB transmission, and PDSCH / PUSCH, etc. can be rate-matched considering SSB resources.

[0118] - For measurement purposes: When in RRC_CONNECTED mode, the network (e.g., BS) can indicate the set of SSBs to be measured within the measurement interval. The SSB set can be indicated per frequency layer. If there is no indication regarding the SSB set, the default SSB set is used. The default SSB set includes all SSBs within the measurement interval. The SSB set can be indicated using the full (e.g., length L) bitmap in RRC signaling. When in RRC_IDLE mode, the default SSB set is used.

[0119] Figure 9 illustrates a process for acquiring system information (SI). A UE can acquire AS / NAS information through the SI acquisition process. The SI acquisition process can be applied to UEs in the RRC_IDLE state, the RRC_INACTIVE state, and the RRC_CONNECTED state. RRC_CONNECTED is a state in which the UE has established an RRC connection with the network. RRC_IDLE is a state in which the UE is not registered in a specific cell and thus does not receive the access stratum (AS) context or other information received from the network. RRC_INACTIVE is a state in which the UE can move within an area established by the radio access network (RAN, e.g., BS(s)) without notifying the RAN while remaining in CM-CONNECTED, which is a state in which the UE has a signaling connection with the core network for connection management (CM). CM_CONNECTED is a state in which the UE has a non-access stratum (NAS) signaling connection with the core network, and CM_IDLE is a state in which the UE does not have any NAS signaling.

[0120] In a 3GPP-based system, SI can be divided into a master information block (MIB) and multiple system information blocks (SIBs). The MIB and multiple SIBs can be further divided into minimum SI and other SI. Here, the minimum SI can be composed of a MIB and a system information block 1 (SystemInformationBlock1, SIB1), and includes basic information required for initial connection and information for acquiring other SI. Here, SIB1 can be referred to as remaining minimum system information (RMSI). For more details, see the following.

[0121] - The MIB is always transmitted on the BCH with a periodicity of 80 ms and repetitions made within 80 ms. The MIB contains information / parameters related to the reception of SIB1 and is transmitted over the PBCH of SSB. During initial cell selection, the UE assumes that half-frames with SSB(s) repeat with a period of 20 ms. Based on the MIB, the UE can check whether a control resource set (CORESET) for the Type0-PDCCH common search space exists. The Type0-PDCCH common search space is a type of PDCCH search space and is used to transmit the PDCCH that schedules the SI message. If a Type0-PDCCH common search space exists, the UE can determine (i) multiple consecutive RBs and one or more consecutive symbols that constitute a CORESET and (ii) PDCCH occasions (i.e., time domain locations for PDCCH reception) based on information in the MIB (e.g., pdcch-ConfigSIB1). If a Type0-PDCCH common search space does not exist, pdcch-ConfigSIB1 provides information about frequency locations where SSB / SIB1 exists and frequency ranges where SSB / SIB1 does not exist.

[0122] - SIB1 is transmitted on the downlink shared channel (DL-SCH) with a periodicity of 160 ms and a variable transmission repetition period within 160 ms. The default transmission repetition period of SIB1 is 20 ms, but the actual transmission repetition period may vary depending on the network implementation. SIB1 contains information related to the availability and scheduling (e.g., transmission period, SI window size) of the remaining SIBs (hereinafter, SIBx, where x is an integer greater than or equal to 2). For example, SIB1 may indicate whether SIBx is broadcast periodically or provided on-demand upon request of the UE. If SIBx is provided on-demand, SIB1 may contain information necessary for the UE to perform an SI request. SIB1 is a cell-specific SIB. The PDCCH scheduling SIB1 is transmitted through the Type0-PDCCH common search space, and SIB1 is transmitted through the PDSCH indicated by the PDCCH.

[0123] - SIBx is included in SI messages and transmitted over the PDSCH. Each SI message is transmitted within a time window (i.e., SI window) that occurs periodically according to the SI scheduling information provided by SIB1.

[0124] Figure 10 illustrates a random access process that may be applied to implementation(s) of the present specification. In particular, Figure 10(a) illustrates a four-step random access process, and Figure 10(b) illustrates a two-step random access process.

[0125] The random access procedure can be used for various purposes, such as initial access, uplink synchronization adjustment, resource allocation, handover, reconfiguration of radio links after radio link failure, and position measurement. The random access procedure is classified into a contention-based procedure and a dedicated (i.e., non-contention-based) procedure. The contention-based random access procedure is commonly used, including initial access, while the dedicated random access procedure is used for handovers, when downlink data arrives at the network, and to reestablish uplink synchronization in the case of position measurement. In the contention-based random access procedure, the UE randomly selects a random access (RA) preamble. Therefore, multiple UEs can transmit the same RA preamble simultaneously, necessitating subsequent contention resolution. In contrast, in the dedicated random access procedure, the UE uses an RA preamble uniquely assigned to the UE by the BS. Therefore, the UE can perform the random access procedure without collisions with other UEs.

[0126] Referring to Fig. 10(a), the contention-based random access process includes the following four steps. Hereinafter, the messages transmitted in steps 1 through 4 may be referred to as Msg1 through Msg4, respectively.

[0127] - Step 1: The UE transmits an RA preamble via PRACH.

[0128] - Step 2: The UE receives a random access response (RAR) from the BS via PDSCH.

[0129] - Step 3: The UE transmits UL data to the BS via PUSCH based on the RAR. Here, the UL data includes layer 2 and / or layer 3 messages.

[0130] - Step 4: The UE receives a contention resolution message from the BS via PDSCH.

[0131] A UE can receive information about random access from a BS through system information. For example, information about RACH occasions associated with SSBs on a cell can be provided through the system information. The UE can select an SSB among the SSBs received on the cell whose reference signal received power (RSRP) measured based on the SSB exceeds a threshold, and transmit an RA preamble through a PRACH associated with the selected SSB. For example, if random access is required, the UE transmits Msg1 (e.g., preamble) to the BS on the PRACH. The BS can distinguish each random access preamble through the time / frequency resource (RA Occasion, RO) on which the random access preamble was transmitted and the random access preamble index (Preamble Index, PI). When the BS receives a random access preamble from the UE, the BS transmits a RAR message to the UE on the PDSCH. To receive a RAR message, the UE monitors a cyclic redundancy check (CRC) masked L1 / L2 control channel (PDCCH) with a Random Access-RNTI (RA-RNTI), which contains scheduling information for the RAR message, within a preset time window (e.g., ra-ResponseWindow). When scheduling information is received through the PDCCH masked with the RA-RNTI, the UE can receive an RAR message from a PDSCH indicated by the scheduling information. Thereafter, the UE determines whether an RAR for itself is included in the RAR message. Whether an RAR for itself exists can be determined by whether a Random Access preamble ID (RAPID) for a preamble transmitted by the UE exists. The index of the preamble transmitted by the UE and the RAPID may be the same.The RAR includes a corresponding random access preamble index, timing offset information for UL synchronization (e.g., timing advance command (TAC), UL scheduling information for Msg3 transmission (e.g., UL grant), and UE temporary identification information (e.g., Temporary-C-RNTI, TC-RNTI). The UE receiving the RAR transmits Msg3 through the PUSCH according to the UL scheduling information and timing offset value in the RAR. Msg3 may include the ID of the UE (or the global ID of the UE). In addition, Msg3 may include information related to an RRC connection request for initial access to the network (e.g., an RRCSetupRequest message). After receiving Msg3, the BS transmits Msg4, which is a contention resolution message, to the UE. If the UE receives the contention resolution message and the contention is successfully resolved, the TC-RNTI is changed to the C-RNTI. Msg4 includes the ID of the UE. And / or RRC connection related information (e.g., RRCSetup message) may be included. If the information transmitted via Msg3 does not match the information received via Msg4, or if Msg4 is not received for a certain period of time, the UE may consider contention resolution to have failed and retransmit Msg3.

[0132] Meanwhile, the dedicated random access process includes the following three steps. Hereinafter, the messages transmitted in steps 0 to 2 may be referred to as Msg0 to Msg2, respectively. The dedicated random access process may be triggered in the UE by the BS using a PDCCH (hereinafter, PDCCH order) for commanding the transmission of an RA preamble.

[0133] - Step 0: BS allocates RA preamble to UE through dedicated signaling.

[0134] - Step 1: The UE transmits an RA preamble via PRACH.

[0135] - Step 2: The UE receives RAR via PDSCH from the BS.

[0136] The operation of steps 1 and 2 of the dedicated random access process may be identical to steps 1 and 2 of the contention-based random access process.

[0137] NR systems may require lower latency than traditional systems. Furthermore, a four-step random access process may be undesirable, especially for latency-sensitive services such as URLLC. A low-latency random access process may be required in various scenarios within NR systems. When implementing implementations of this specification in conjunction with a random access process, implementations of this specification may be implemented in conjunction with the following two-step random access process to reduce the latency of the random access process.

[0138] Referring to Fig. 10(b), the two-step random access process may be composed of two steps: transmission of MsgA from a UE to a BS and transmission of MsgB from the BS to the UE. The MsgA transmission may include transmission of an RA preamble via a PRACH and transmission of an UL payload via a PUSCH. In the MsgA transmission, the PRACH and PUSCH may be transmitted using time division multiplexing (TDM). Alternatively, in the MsgA transmission, the PRACH and PUSCH may be transmitted using frequency division multiplexing (FDM).

[0139] A BS that receives MsgA can transmit MsgB to the UE. MsgB can include an RAR for the UE.

[0140] An RRC connection request related message (e.g., an RRCSetupRequest message) requesting to establish a connection between the RRC layer of the BS and the RRC layer of the UE may be transmitted in the payload of MsgA. In this case, MsgB may be used to transmit RRC connection related information (e.g., an RRCSetup message). Alternatively, the RRC connection request related message (e.g., an RRCSetupRequest message) may be transmitted via a PUSCH transmitted based on a UL grant in MsgB. In this case, the RRC connection related information (e.g., an RRCSetup message) related to the RRC connection request may be transmitted via a PDSCH associated with the PUSCH transmission after the PUSCH transmission based on MsgB.

[0141] Below, the physical channels that can be used in 3GPP-based wireless communication systems are described in more detail.

[0142] The PDCCH carries DCI. For example, the PDCCH (i.e., DCI) carries the transmission format and resource allocation of the downlink shared channel (DL-SCH), resource allocation information for the uplink shared channel (UL-SCH), paging information for the paging channel (PCH), system information on the DL-SCH, resource allocation information for control messages of a layer (hereinafter, upper layer) located above the physical layer in the protocol stacks of the UE / BS, such as a random access response (RAR) transmitted on the PDSCH, transmission power control commands, activation / release of configured scheduling (CS), etc. The DCI that includes resource allocation information for the DL-SCH is also called PDSCH scheduling DCI, and the DCI that includes resource allocation information for the UL-SCH is also called PUSCH scheduling DCI. The DCI includes a cyclic redundancy check (CRC), and the CRC is masked / scrambled with various identifiers (e.g., radio network temporary identifier (RNTI)) depending on the owner or intended use of the PDCCH. For example, if the PDCCH is for a specific UE, the CRC is masked with the UE identifier (e.g., cell RNTI (C-RNTI)). If the PDCCH is for paging, the CRC is masked with the paging RNTI (P-RNTI). If the PDCCH is for system information (e.g., system information block (SIB)), the CRC is masked with the system information RNTI (SI-RNTI). If the PDCCH is for a random access response, the CRC is masked with the random access RNTI (RA-RATI).

[0143] When a PDCCH on one serving cell schedules a PDSCH or PUSCH on another serving cell, this is called cross-carrier scheduling. Cross-carrier scheduling using the carrier indicator field (CIF) can allow the PDCCH of a serving cell to schedule resources on another serving cell. On the other hand, when a PDSCH on a serving cell schedules a PDSCH or PUSCH on the serving cell, this is called self-carrier scheduling. When cross-carrier scheduling is used in a cell, the BS can provide the UE with information about the cell that schedules the cell. For example, the BS can provide the UE with information about whether the serving cell is scheduled by a PDCCH on another (scheduling) cell or by the serving cell, and if the serving cell is scheduled by another (scheduling) cell, which cell signals downlink assignments and uplink grants for the serving cell. In this specification, a cell that carries a PDCCH is called a scheduling cell, and a cell in which transmission of a PUSCH or PDSCH is scheduled by DCI included in the PDCCH, i.e., a cell that carries a PUSCH or PDSCH scheduled by the PDCCH, is called a scheduled cell.

[0144] The PDSCH is a physical layer DL channel for DL ​​data transport. PDSCH carries downlink data (e.g., DL-SCH transport blocks) and employs modulation methods such as Quadrature Phase Shift Keying (QPSK), 16 Quadrature Amplitude Modulation (QAM), 64 QAM, and 256 QAM. Transport blocks (TBs) are encoded to generate codewords. A PDSCH can carry up to two codewords. Scrambling and modulation mapping are performed for each codeword, and the modulation symbols generated from each codeword can be mapped to one or more layers. Each layer is mapped to radio resources along with the DMRS, generating an OFDM symbol signal and transmitting it through the corresponding antenna port.

[0145] A UE must have uplink resources available to it for UL-SCH data transmission, and downlink resources available to it for DL-SCH data reception. Uplink and downlink resources are assigned to the UE through resource allocation by the BS. Resource allocation may include time domain resource allocation (TDRA) and frequency domain resource allocation (FDRA). In this specification, uplink resource allocation is also referred to as uplink grant, and downlink resource allocation is also referred to as downlink assignment. An uplink grant is dynamically received by the UE on the PDCCH or within the RAR, or is semi-persistently configured to the UE by RRC signaling from the BS. A downlink assignment is dynamically received by the UE on the PDCCH, or is semi-persistently configured to the UE by RRC signaling from the BS.

[0146] In UL, the BS can dynamically allocate uplink resources to the UE via PDCCH(s) addressed to a cell radio network temporary identifier (C-RNTI). The UE monitors the PDCCH(s) to find possible uplink grant(s) for UL transmission. Furthermore, the BS can allocate uplink resources to the UE using the configured grant(s). Two types of configured grants can be used: Type 1 and Type 2. For Type 1, the BS directly provides the configured uplink grant (including the periodicity) via RRC signaling. For Type 2, the BS can configure the period of the RRC configured uplink grant via RRC signaling, and signal and activate or deactivate the configured uplink grant via a PDCCH addressed to a configured scheduling RNTI (CS-RNTI). For example, for Type 2, a PDCCH addressed to CS-RNTI implicitly indicates that the corresponding uplink grant can be reused according to a period set by RRC signaling until it is deactivated.

[0147] In DL, the BS can dynamically allocate downlink resources to the UE via PDCCH(s) addressed with the C-RNTI. The UE monitors the PDCCH(s) to discover possible downlink assignments. Additionally, the BS can allocate downlink resources to the UE using semi-persistent scheduling (SPS). The BS can configure the period of the configured downlink assignments via RRC signaling, and can signal and activate or deactivate the configured downlink assignments via the PDCCH addressed with the CS-RNTI. For example, a PDCCH addressed with the CS-RNTI implicitly indicates that the corresponding downlink assignment can be reused according to the period configured by the RRC signaling until it is deactivated.

[0148] Figure 11 illustrates an example of PDSCH time domain resource allocation by PDCCH and an example of PUSCH time domain resource allocation by PDCCH.

[0149] The DCI carried by the PDCCH for scheduling the PDSCH or PUSCH includes a time domain resource assignment (TDRA) field, which provides a value m for a row index m+1 of an allocation table for the PDSCH or PUSCH. A predefined default PDSCH time domain allocation is applied as the allocation table for the PDSCH, or a PDSCH time domain resource allocation table configured by the BS through RRC signaling pdsch-TimeDomainAllocationList is applied as the allocation table for the PDSCH. A predefined default PUSCH time domain allocation is applied as the allocation table for the PUSCH, or a PUSCH time domain resource allocation table configured by the BS through RRC signaling pushch-TimeDomainAllocationList is applied as the allocation table for the PUSCH. The PDSCH time domain resource allocation table to be applied and / or the PUSCH time domain resource allocation table to be applied may be determined according to fixed / predefined rules (e.g., see 3GPP TS 38.214).

[0150] In the PDSCH time domain resource configurations, each indexed row defines a DL allocation-to-PDSCH slot offset K0, a start and length indicator value SLIV (or directly a starting position (e.g., a starting symbol index S) and an allocation length (e.g., a number of symbols L) of a PDSCH within a slot), and a PDSCH mapping type. In the PUSCH time domain resource configurations, each indexed row defines a UL grant-to-PUSCH slot offset K2, a starting position (e.g., a starting symbol index S) and an allocation length (e.g., a number of symbols L) of a PUSCH within a slot, and a PUSCH mapping type. K0 for PDSCH or K2 for PUSCH indicates the difference between a slot with a PDCCH and a slot with a PDSCH or PUSCH corresponding to the PDCCH. SLIV is a joint indication of a starting symbol S relative to the start of a slot with a PDSCH or PUSCH and the number L of consecutive symbols counted from the symbol S. For PDSCH / PUSCH mapping type, there are two mapping types: one is mapping type A and the other is mapping type B. For PDSCH / PUSCH mapping type A, a demodulation reference signal (DMRS) is mapped to a PDSCH / PUSCH resource at the beginning of a slot, and one or two symbols of the PDSCH / PUSCH resource can be used as DMRS symbol(s) depending on other DMRS parameters. For example, for PDSCH / PUSCH mapping type A, the DMRS is located at the third symbol (symbol #2) or the fourth symbol (symbol #3) in a slot depending on RRC signaling. For PDSCH / PUSCH mapping type B, the DMRS is mapped based on the first OFDM symbol of the PDSCH / PUSCH resource, and one or two symbols from the first symbol of the PDSCH / PUSCH resource can be used as DMRS symbol(s) depending on other DMRS parameters.For example, in the case of PDSCH / PUSCH mapping type B, DMRS is located in the first symbol allocated for PDSCH / PUSCH. In this specification, PDSCH / PUSCH mapping type may be referred to as mapping type or DMRS mapping type. For example, in this specification, PUSCH mapping type A may be referred to as mapping type A or DMRS mapping type A, and PUSCH mapping type B may be referred to as mapping type B or DMRS mapping type B.

[0151] The above scheduling DCI includes a frequency domain resource assignment (FDRA) field that provides allocation information regarding resource blocks used for PDSCH or PUSCH. For example, the FDRA field provides the UE with information regarding the cell for PDSCH or PUSCH transmission, information regarding the BWP for PDSCH or PUSCH transmission, and information regarding resource blocks for PDSCH or PUSCH transmission.

[0152] A control resource set (CORESET), which is a set of time-frequency resources for which a UE can monitor PDCCH, may be defined and / or configured. A CORESET consists of a set of physical resource blocks (PRBs) with a duration of one to three OFDM symbols. The PRBs constituting the CORESET and the CORESET duration may be provided to the UE via higher layer (e.g., RRC) signaling. Within the configured CORESET(s), a set of PDCCH candidates is monitored according to the corresponding search space sets. In this specification, monitoring implies decoding (aka blind decoding) each PDCCH candidate according to the monitored DCI formats. The master information block (MIB) on the PBCH provides the UE with parameters (e.g., CORESET#0 configuration) for monitoring the PDCCH for scheduling the PDSCH carrying the system information block 1 (SIB1). The PBCH may also indicate that there is no associated SIB1, in which case the UE may be instructed on other frequencies to search for the SSB associated with SIB1, as well as a frequency range in which it can assume that there is no SSB associated with SSB1. At least CORESET#0, which is the CORESET for scheduling SIB1, may be configured via the MIB or dedicated RRC signaling.

[0153] More than one CORESET may be configured for a UE, and multiple CORESETs may overlap in the time / frequency domain.

[0154] The set of PDCCH candidates monitored by the UE is defined in terms of PDCCH search space sets. The search space set may be a common search space (CSS) set or a UE-specific search space (USS) set. Each CORESET configuration is associated with one or more search space sets, and each search space set is associated with one CORESET configuration.

[0155] A set of PDCCH candidates may be monitored in one or more CORESETs on an active DL BWP on each activated serving cell for which PDCCH monitoring is configured, where monitoring implies receiving each PDCCH candidate and decoding it according to the monitored DCI formats.

[0156] SS sets can be configured via system information (e.g., MIB) or UE-specific higher layer (e.g., RRC) signaling. Each DL BWP of a serving cell can have up to S (e.g., 10) SS sets configured. For example, the following parameters / information can be provided for each SS set. Each SS set is associated with one CORESET, and each CORESET configuration can be associated with one or more SS sets.

[0157] - searchSpaceId: Indicates the ID of the SS set.

[0158] - controlResourceSetId: Indicates the CORESET associated with the SS set.

[0159] - monitoringSlotPeriodicityAndOffset: Indicates the PDCCH monitoring period period (in slot units) and the PDCCH monitoring period offset (in slot units).

[0160] - monitoringSymbolsWithinSlot: Indicates the first OFDMA symbol(s) for PDCCH monitoring within the slot where PDCCH monitoring is configured. It is indicated through a bitmap, and each bit corresponds to each OFDMA symbol within the slot. The MSB of the bitmap corresponds to the first OFDM symbol within the slot. The OFDMA symbol(s) corresponding to the bit(s) with a bit value of 1 corresponds to the first symbol(s) of the CORESET within the slot.

[0161] - nrofCandidates: AL={1, 2, 4, 8, 16} indicates the number of PDCCH candidates (e.g., one of 0, 1, 2, 3, 4, 5, 6, 8).

[0162] - searchSpaceType: Indicates whether the SS type is CSS or USS.

[0163] - DCI format: Indicates the DCI format of the PDCCH candidate.

[0164] Based on the CORESET / SS set configuration, the UE can monitor PDCCH candidates in one or more SS sets within a slot. The occasions (e.g., time / frequency resources) during which PDCCH candidates should be monitored are defined as PDCCH (monitoring) occasions. One or more PDCCH (monitoring) occasions can be configured within a slot.

[0165] UE uses DRX to reduce power consumption. UE operating based on DRX repeats ON / OFF for reception operation. The features of DRX utilized for the purpose of reducing unnecessary power consumption of UE are as follows. DRX defines a structure for UE in RRC_IDLE state where RRC connection between UE and BS is not established (hereinafter referred to as I-DRX) and a structure for UE in RRC_CONNECTED state where RRC connection between UE and BS is established (hereinafter referred to as C-DRX). Both DRX structures are designed to reduce unnecessary power consumption in other periods by defining a period (e.g., active time period or on-duration period) in which UE can expect reception of DL signals to occur periodically. For reference, in the case of C-DRX, the start position of On-duration occurs periodically in the Rel-16 standard, and the size of the cycle that can be configured at this time (i.e., DRX cycle) can be determined / set through upper layer signaling, such as RRC signaling, provided by the BS to the UE.

[0166] Figure 12 illustrates a discontinuous reception (DRX) operation. In particular, Figure 12 illustrates a DRX cycle for a UE in RRC_CONNECTED state.

[0167] Referring to FIG. 12, a DRX cycle consists of an ON period and an Opportunity for DRX. A DRX cycle defines a time interval in which an ON period is periodically repeated, followed by a possible period of inactivity. The ON period represents a time interval during which the UE performs PDCCH monitoring to receive a PDCCH. When DRX is configured, the UE performs PDCCH monitoring during the ON period. If a PDCCH is successfully detected during PDCCH monitoring, the UE starts an inactivity timer and remains awake. On the other hand, if no PDCCH is successfully detected during PDCCH monitoring, the UE enters a sleep state after the ON period ends. Therefore, when DRX is configured, the UE may perform PDCCH monitoring / reception discontinuously in the time domain when performing a process and / or method according to the implementation(s) of this specification. For example, when DRX is configured, the PDCCH reception occasion (e.g., slot having PDCCH search space) in this specification may be configured discontinuously according to the DRX configuration. On the other hand, when DRX is not configured, the UE may perform PDCCH monitoring / reception continuously in the time domain. For example, when DRX is not configured, the PDCCH reception occasion (e.g., slot having PDCCH search space) may be configured continuously. On the other hand, regardless of whether DRX is configured, PDCCH monitoring may be restricted in the time period configured as the measurement gap. DRX configuration information is received via upper layer (e.g., RRC) signaling, and whether DRX is turned on / off is controlled by the DRX command of the MAC layer. When DRX is configured, the UE may perform PDCCH monitoring discontinuously, as illustrated in FIG. 12.

[0168] The following table illustrates the UE processes related to DRX. Referring to the following table, DRX configuration information is received via upper layer (e.g., RRC) signaling, and DRX ON / OFF is controlled by the DRX command of the MAC layer. When DRX is configured, the UE can perform PDCCH monitoring discontinuously, as illustrated in FIG. 12.

[0169]

[0170] Here, MAC-CellGroupConfig contains configuration information required to set MAC parameters for a cell group. MAC-CellGroupConfig may also contain configuration information related to DRX. For example, MAC-CellGroupConfig may contain DRX-related information as follows.

[0171] - Value of drx-onDurationTimer: Sets the duration at the start of the DRX cycle.

[0172] - Value of drx-SlotOffset: Sets the delay before starting drx-onDurationTimer.

[0173] - Value of drx-InactivityTimer: Sets the period after which a PDCCH epoch indicates a new UL or DL ​​transmission to the MAC entity.

[0174] - Value of drxRetransmissionTimerDL (per DL HARQ process except for the broadcast process): Sets the maximum duration until a DL retransmission is received.

[0175] - Value of drxRetransmissionTimerUL (per UL HARQ process): Sets the maximum duration until a grant for UL retransmission is received.

[0176] - Value of drx-HARQ-RTT-TimerDL (per DL HARQ process except for the broadcast process): Sets the maximum period of time after a DL initial transmission is received until a DL assignment for HARQ retransmission is received.

[0177] - Value of drx-HARQ-RTT-TimerUL (per UL HARQ process): Sets the maximum period from when a grant for UL initial transmission is received until a grant for UL retransmission is received.

[0178] - drx-LongCycleStartOffset: Sets the Long DRX cycle and drx-StartOffset, which defines the subframe where the Long and Short DRX cycles start.

[0179] - drx-ShortCycle (optional): Sets the short DRX cycle.

[0180] - drx-ShortCycleTimer (optional): Sets the duration for which the UE should follow the Short DRX cycle. For example, a value in multiples of the Short DRX cycle can be set by drx-CylceTimer. For example, the value of n can correspond to n*drx-ShortCycle.

[0181] A UE may perform PDCCH monitoring on serving cells within a DRX group when the DRX group is within its active time. Here, a DRX group is a group of serving cells configured by RRC and having the same DRX active time. Here, the active time is a total duration for which the UE monitors the PDCCH, and may include an ON period of a DRX cycle, a time for which the UE performs continuous reception while an inactivity timer has not expired, and a time for which the UE performs continuous reception while waiting for a retransmission opportunity. For example, when DRX is configured, the active time for serving cells within a DRX group is i) while drx-onDurationTimer or drx-InactivityTimer configured for the DRX group is running; or ii) while drx-RetransmissionTimerDL or drx-RetransmissionTimerUL is running on any serving cell within the DRX group; or ra-ContentionResoultionTimer or msgB-RsponseWindow is running; or a PDCCH indicating a new transmission addressed to a C-RNTI addressed to the MAC entity of the UE is not received after successful reception of a random access response to a random access preamble that is not selected by the MAC entity among the contention-based random access preambles.

[0182] A UE can be configured with one or more DRX groups via RRC signaling from a BS. For example, if two DRX groups are configured, each serving cell is uniquely assigned to one of the two DRX groups. The DRX parameters drx-onDurationTimer and drx-InactivityTimer are configured separately for each DRX group, and the DRX parameters drx-SlotOffset, drx-RetransmissionTimerDL, drx-RetransmissionTimerUL, drx-LongCycleStartOffset, drx-ShortCycle (optional), drx-ShortCycleTimer (optional), drx-HARQ-RTT-TimerDL, and drx-HARQ-RTT-TimerUL are common to the DRX groups. Since each serving cell belongs to only one of the DRX groups, and the DRX parameters drx-onDurationTimer and drx-InactivityTimer are set for each DRX group, and the remaining DRX parameters are common to the DRX groups, it can be said that a serving cell is associated with only one set of DRX parameters.

[0183] Figure 13 illustrates a case where a Long DRX cycle and a Short DRX cycle are set. In particular, Figure 13 illustrates a case where drx-ShortCycleTimer is set to 2.

[0184] A BS can configure a Long DRX cycle and an additional Short DRX cycle that is shorter than the Long DRX cycle. If a Short DRX cycle is not configured, the UE follows the Long DRX cycle. When configuring a Short DRX cycle, the BS sets the duration of the Long DRX cycle to be a positive integer multiple of the Short DRX cycle. The same onDurationTimer value is configured for the Long DRX cycle and the Short DRX cycle. If there is no data activity during the ON period of the Long DRX cycle (e.g., no PDCCH reception), the UE follows the Long DRX cycle as if the Short DRX cycle is not configured. If there is data activity during the ON period of the Long DRX cycle, for example, while drx-onDurationTimer is running, the UE switches to the Short DRX cycle and follows the Short DRX cycle for a certain period of time (e.g., while drx-ShortCycleTimer is running). At this time, the start of the ON period in the Short DRX cycle is determined by drx-StartOffset and drx-SlotOffset, just like the Long DRX cycle. Referring to FIG. 13, if there is no data activity during the time following the Short DRX cycle, for example, if there is no data activity during the period defined by drx-ShortCycleTimer*drx-ShortCycle, the UE switches to the Long DRX cycle after drx-ShortCycleTimer Short DRX cycles.

[0185] Energy conservation of base stations (BSs) is a key consideration in wireless communication systems, including 3GPP, as it can contribute to building eco-friendly networks by reducing carbon emissions and reducing the operational expenditure (OPEX) of telecommunications operators. In particular, the introduction of 5G communications will require higher transmission rates, necessitating BSs to be equipped with more antennas and provide services over wider bandwidths and frequency bands. Consequently, recent studies have shown that BS energy costs have reached up to 20% of total OPEX. This heightened interest in BS energy conservation led to the approval of a new study item, "Study on Network Energy Savings," in 3GPP NR Release 18. For example, to improve the energy saving capability of BS from the perspective of transmission and reception, the study investigates how to achieve dynamic and / or semi-static and finer granularity adaptation of transmission and / or reception to more efficient operation with one or more network energy saving techniques in time, frequency, space and power domains using potential assistance / feedback of UE and potential UE assistance information.

[0186] The following enhancement techniques may be considered:

[0187] > Specify SSB-less SCell operation for inter-band CA for FR1 and co-located cells, where a UE measures SSB transmitted on PCell or another SCell for an SCell's time / frequency synchronization (including downlink AGC), and L1 / L3 measurements, including potential enhancement on SCell activation procedures if necessary.

[0188] > Specify enhancement on cell DTX / DRX mechanism including the alignment of cell DTX / DRX and UE DRX in RRC_CONNECTED mode, and inter-node information exchange on cell DTX / DRX

[0189] > Specify the following techniques in spatial and power domains:

[0190] >> Specify necessary enhancements on CSI and beam management related procedures including measurement and report, and signaling to enable efficient adaptation of spatial elements (e.g., antenna ports, active transceiver chains).

[0191] >> Specify necessary enhancements on CSI-related procedures including measurement and report, and signaling to enable efficient adaptation of power offset values ​​between PDSCH and CSI-RS.

[0192] > Specify mechanism(s) to prevent legacy UEs camping on cells adopting the Rel-18 NES techniques, if necessary.

[0193] > Specify conditional handover (CHO) procedure enhancement(s) in case source / target cell is in NES mode.

[0194] > Specify inter-node beam activation and enhancements on restricting paging in a limited area.

[0195] > Specify the corresponding radio resource management / radio frequency (RRM / RF) core requirements, if necessary, for the above features.

[0196] A BS can apply technologies such as controlling the on / off duration in the time domain for NES purposes, controlling transmission / reception resources for UE-common or UE-specific signals / channels, changing the amount of frequency domain resources, controlling transmission power, or turning antenna port(s) or TRP(s) on / off in the spatial domain. A state in which such technologies (hereinafter, referred to as NES_tech for convenience) are applied is referred to as an NES mode or NES state.

[0197] Figure 14 illustrates an operating procedure in a BS that supports network energy saving (NES) technology.

[0198] Referring to FIG. 14, the BS identifies or determines the NES solution(s) to be applied (S1401). The NES solution(s) may be related to control of signal transmission / reception (e.g., on / off), beam operation, handover procedures, channel measurement and reporting, etc. The NES solution(s) to be applied may be adaptively selected or predefined depending on the current situation (e.g., cell load level, characteristics of connected UEs, etc.). The BS that has identified (or determined) the NES solution(s) may perform signaling for the NES (S1403). The specific signaling procedure may vary depending on the identified NES solution(s). For example, the BS may transmit common information about the NES solution(s), transmit configuration information necessary for NES operation to at least one UE, or transmit control information regarding the progress of the NES operation to at least one UE. Additionally, the BS may receive capability information related to the NES from at least one UE. Thereafter, the BS may perform operations for the NES (S1405). At this time, the BS may perform operations for the NES based on previously performed signaling. For example, based on system information, configuration information, and control information transmitted through signaling, the BS may turn on or off transmission / reception of a specific signal, turn on / off elements in the spatial domain, or adjust resources for transmission / reception of a measurement signal.

[0199] Through a procedure similar to that in Fig. 14, NES technology can be implemented. Examples of NES solutions that can be implemented through a procedure similar to that in Fig. 14 are as follows.

[0200] > Intra-system energy saving solution: A radio access network (RAN) node can request a neighboring RAN node to switch at least one SSB beam into its deactivated cell, or can perform paging using a limited set of beams to an inactive UE (e.g., a stationary UE).

[0201] > Inter-system energy saving solution: NG-RAN nodes that own capacity booster cells can autonomously transition those cells to inactive state.

[0202] > SSB-less SCell solution: If the SSB configuration for the SCell or the SSB-based RRM measurement timing configuration (SSB measurement timing configuration (SMTC)) is not provided, the UE can obtain the timing reference and automatic gain control (AGC) source from another serving cell. In FR1 or FR2, the BS can configure intra-band carrier aggregation (CA) or inter-band CA including the SCell without SSB transmission, in which case the SSB / SIB transmission can be triggered by the wake up signal (WUS) of the UE. Accordingly, the periodicity of common channels / signals such as SSB increases, so the BS can stay in the sleep state for a longer time.

[0203] > Cell DTX / DRX Solution: In order to reduce the downlink transmission / uplink reception active time of the BS, a common periodic cell DTX / DRX pattern (e.g., active and inactive periods) may be configured for UEs within a cell having the feature. Here, the cell DTX pattern and the cell DRX pattern may be configured and activated separately, and up to two cell DTX / DRX patterns may be configured per MAC entity. When cell DTX is configured and activated, at least one of monitoring for semi-persistent scheduling (SPS) occasions or PDCCH monitoring may be suspended during the cell DTX inactive period. When cell DRX is configured and activated, at least one of transmission on configured grant (CG) resources or scheduling request (SR) transmission may be suspended during the cell DRX inactive period. Cell DTX / DRX can be activated / deactivated via RRC signaling or L1 group common signaling (e.g., PDCCH on CSS). Parameters such as active duration and cycle can be configured for cell DTX / DRX. Active duration is the period during which the UE receives a PDCCH or SPS occasion and waits to transmit SR or CG, and cycle specifies the periodic repetition of active and inactive periods. When both cell DTX and cell DRX are configured, parameters such as active duration and cycle are common.If the BS recognizes an emergency call or a public safety related service (e.g., multimedia priority service (MPS) or mission critical service (MCS)), the network may release or deactivate the cell DTX / DRX configuration so as not to affect the service. In addition, at least some overlap is required between the active period of the connected mode DRX of the UE and the active period of the cell DTX / DRX. For example, the connected mode DRX periodicity of the UE may be a multiple of the cell DTX / DRX periodicity or vice versa.

[0204] > Conditional handover (CHO) solution: The CHO procedure, which is performed in a way that the execution of the handover is determined by the UE, is used while the NES technology is applied (e.g., when the cell activates or deactivates cell DTX / DRX). In this case, the UE can use NES-specific CHO events to initiate CHO for a candidate cell, and the reception of a DCI activating the CHO condition(s) set by the NES event indication can be applied as an additional triggering condition for this.

[0205] > Spatial and Power Domain Adaptation Solution: To support the BS for transmitter muting and / or transmit power adaptation, the UE may be configured to report multiple CSI entries in a CSI report based on multiple sub-configurations. Each sub-configuration may correspond to a spatial domain adaptation pattern (e.g., a subset of available spatial elements) and / or a power offset between a data channel (e.g., a PDSCH) and CSI-RSs. Depending on the application of the spatial and power domain adaptation solution, the CSI configuration, measurement, and / or reporting behavior may be affected.

[0206] Below, several implementations of this specification are described that save energy by differently configuring UL WUS resources depending on the purpose / scenario for which the UE requests on-demand SIB1, or by differently performing operations after the BS transmits SIB1 by indicating in advance (early indication) the purpose of requesting SIB1 to the BS.

[0207] Figure 15 is an example of a process for carrier aggregation (CA) operation using an SSB-less secondary cell (SCell).

[0208] Referring to FIG. 15, the BS may transmit configuration information for an SCell to be aggregated through a PCell or an SCell already configured to the UE (S1501). For example, the BS may transmit configuration information for a CA to provide a service to the UE through a CA operation. Here, the CA operation may be an intra-band CA or an inter-band CA. For example, the configuration information for the SCell may include information including information for adding the SCell (e.g., sCellToAddModList), and specifically, may include a cell index, a physical cell identifier, information related to DL-UL configuration, information related to BWP, information related to cell DTX / DRX, information related to downlink frequency (e.g., FrequencyInfoDL), etc. Then, the UE may determine a configuration for the CA operation (S1503) and perform communication using the PCell and SCell of the BS (S1505a, S1505b). In some implementations, the UE can determine that an SCell is an SSB-less SCell based on information related to the downlink frequency included in the configuration information, and can check related parameters. For example, the UE can determine that an SCell is an SSB-less SCell by checking for the presence of a parameter indicating that it is an SSB-less SCell (e.g., SSBlessSCell), and can determine the timing reference and AGC source for the SCell based on information about the reference cell (e.g., referenceCell). In the example of Figure 15, the reference cell may be the PCell. In this case, the UE can use the PCell as a timing reference and AGC source for communications on the SCell.

[0209] The following table illustrates part of the RRC information element (IE) FrequencyInfoDL, which provides the downlink carrier and basic parameters for transmission on the downlink carrier.

[0210]

[0211] The above IEFrequencyInfoDL may be included in the RRC configuration DownlinkConfigCommon or DownlinkConfigCommonSIB, which provides common downlink parameters of the cell.

[0212] In the above table, the field absoluteFrequencySSB indicates the frequency of the SSB to be used for this serving cell, and the SSB-related parameters provided for the serving cell (e.g., SSB index) refer to this SSB frequency unless otherwise stated. The cell-defining SSB (CD-SSB) of the PCell is always on the sync raster. If the frequencies are identifiable even with the GSCN value, the frequencies are considered to be on the sync raster. If the field absoluteFrequencySSB is absent in the IEFrequencyInfoDL, the SSB-related parameters (e.g., ssb-PositionsInBurst, ssb-periodicityServingCell, and subcarrierSpacing in ServingCellConfigCommonIE) are absent. If the above field absoluteFrequencySSB is absent, the UE may obtain timing reference from an SpCell or SCell, if applicable, from an SpCell or SCell indicated by referenceCell, or from a default cell. This is supported when the SCell for which the UE obtains the timing reference is in the same or a different frequency band as the cell from which the UE obtains the timing reference (e.g., the SpCell or the SCell, respectively).

[0213] In the table above, the field referenceCell can indicate a reference cell, which is a cell that provides a timing reference and AGC source for a non-SSB SCell. If the reference cell is an SCell or PSCell, it is an activated SCell or an activated PSCell. If this field is absent, the default cell is the reference cell.

[0214] The UE can be provided with the periodicity of half frames for receiving SSBs for each serving cell by the RRC parameter ssb-perodicitiyServingCell. If the UE is not configured with the periodicity of half frames for receiving SSBs, the UE assumes the periodicity of the half frame. The UE can assume that the periodicity is the same for all SSBs in the serving cell. For initial cell selection, the UE can assume that half frames with SSBs occur with a period of two frames.

[0215] On-demand SSB

[0216] In some implementations, a method may be considered to reduce energy consumption by having the BS transmit SSB on a specific cell through an on-demand SSB process and not transmit SSB on the specific cell when an on-demand SSB process is not available. Hereinafter, SSB transmitted for a certain period or interval upon request by the UE is referred to as on-demand SSB for convenience. In the existing NR system, it was difficult to reduce energy consumption even when the BS had no data to receive or send because SSB had to be transmitted periodically for purposes such as time / frequency synchronization or RRM measurement. Considering this, in some implementations, the BS may not perform SSB transmission until an on-demand SSB process is involved, thereby reducing BS energy consumption. The on-demand SSB process may be triggered by one of the following methods.

[0217] 1) The UE requests SSB transmission from the BS by transmitting an uplink signal / channel (e.g., PRACH, PUCCH, PUSCH, SRS, etc. in a 3GPP-based system);

[0218] 2) Requesting SSB transmission from BS (or TRP) #1 to BS (or TRP) #2 via an interface between BSs (e.g., Xn interface in NR-based systems) or backhaul signaling; or

[0219] 3) Signaling whether SSB transmission is possible for the corresponding SCell through SCell activation / deactivation signaling.

[0220] Considering coexistence with UEs according to existing NR standards, some scenarios (e.g., 3GPP Release 19) may be limited to on-demand SSB operation for connected mode UEs and SCells. However, in future releases or next generation communication systems, on-demand SSB operation (for SSB transmission on PCell) considering inactive or idle mode UEs or initially attached UEs may be defined. In addition, CA including the SCell can be applied to both intra-band CA and inter-band CA, and SSB on the SCell transmitted through the on-demand SSB process can be utilized for at least the following functionalities: time / frequency synchronization, layer 1 (L1) / layer 3 (L3) measurement, and SCell activation.

[0221] On-demand SIB1 transmission

[0222] In some implementations, a method may be considered to reduce energy consumption by having the BS transmit SIB1 for a specific cell through an on-demand SIB1 process and not transmit SIB1 for the cell when an on-demand SIB1 process is not available. Hereinafter, SIB1 transmitted for a certain period or interval upon request by a UE is referred to as on-demand SIB1 for convenience. In the existing NR system, SIB1 containing system information, random access information, etc. for initial access or idle mode UEs to access a cell had to be provided periodically, making it difficult to reduce energy consumption even when the BS had no data to receive or send. Considering this, some implementations may reduce BS energy consumption by allowing the BS to not transmit SIB1 until an on-demand SIB1 process is involved and then transmit SIB1. During the on-demand SIB1 process, the BS's SIB1 transmission may be triggered by the UE transmitting an uplink signal / channel (e.g., PRACH in a 3GPP-based system).

[0223] Figures 16 through 18 illustrate on-demand SIB1 transmission scenarios related to some implementations of this specification.

[0224] The following scenarios may be considered in relation to on-demand SIB1 transmission according to some implementations of this specification, but some implementations of this specification may not be limited to the following scenarios.

[0225] 1) Scenario 1: As illustrated in FIG. 16, a UE that receives an SSB (and / or other downlink signal / channel) from a certain Cell#1 and recognizes that SIB1 is not transmitted on the said Cell#1 may trigger SIB1 transmission by transmitting a signal requesting SIB1 (hereinafter, a wake-up signal (WUS) for convenience) based on information provided in the SSB (and / or other downlink signal / channel) and / or predetermined information. The BS that receives the WUS may transmit a specific DL signal / channel (corresponding to an ACK for the WUS) on Cell#1 in response thereto, or may transmit SIB1 on Cell#1 (or without transmitting the DL signal / channel).

[0226] 2) Scenario 2: As illustrated in FIG. 17, a UE may attempt to camp on Cell#2 upon receiving an SSB (and / or other downlink signal / channel such as SIB1) from a Cell#1 and recognizing that SIB1 is not transmitted on Cell#2. The UE may trigger SIB1 transmission for Cell#2 by transmitting a signal (e.g., WUS) requesting SIB1 on Cell#1 based on information provided in the received SSB (and / or other downlink signal / channel such as SIB1) and / or predetermined information. The BS receiving the WUS may transmit a specific DL signal / channel (corresponding to an ACK for the WUS) in response thereto (on Cell#1 or Cell#2), and may transmit SIB1 for Cell#2 on Cell#1 or Cell#2 (or without transmitting the DL signal / channel).

[0227] 3) Scenario 3: As illustrated in FIG. 18, a UE may receive an SSB (and / or other downlink signal / channel such as SIB1) from a certain Cell#1 and recognize that SIB1 is not transmitted on the said Cell#2, and may attempt to camp on Cell#2. The UE may trigger transmission of SIB1 for Cell#2 by transmitting a signal (e.g., WUS) requesting SIB1 on Cell#2 based on information provided in the received SSB (and / or other downlink signal / channel such as SIB1) and / or predetermined information. The BS receiving the WUS may transmit a specific DL signal / channel (corresponding to an ACK for the WUS) in response thereto (on Cell#1 or Cell#2), and may transmit SIB1 for Cell#2 on Cell#1 or Cell#2 (or without transmitting the DL signal / channel).

[0228] When multiple cells are involved in on-demand SIB1 operation, such as in Scenario 2 or 3 above, Cell#1 and Cell#2 can be defined as follows.

[0229] - Cell A (= Cell#1): a cell that is periodically transmitting at least its own SIB1.

[0230] - NES cell (= Cell#2): a cell that may transmit SIB1 in response to UL WUS from a UE.

[0231] For example, Cell A may refer to a cell on which SIB1 information for that cell is periodically transmitted, and may also be referred to as Cell#1 or an anchor cell. Furthermore, NES cell may refer to a cell on which SIB1 is provided in response to an uplink WUS from a UE, and may also be referred to as Cell#2 or a non-anchor cell.

[0232] A UE can discover a cell and recognize that it is a NES cell (requiring on-demand SIB1 operation) through at least one or a combination of the following methods:

[0233] - The UE can recognize that it is a NES cell through SIB and / or WUS configuration information (provided from Cell A).

[0234] - The UE can recognize that it is a NES cell through information such as the center frequency of PBCH / MIB / SSB (received from the NES cell).

[0235] - The UE can recognize that it is a NES cell through the DCI (received from the NES cell). The DCI can be received in the CORESET / search space configured through the PBCH, MIB, or SSB (received from the NES cell). Additionally, a separate RNTI value for the DCI can be pre-configured / defined.

[0236] - If the UE attempts to receive SIB1 of the cell and fails to receive SIB1 for a certain period of time, it can recognize that it is a NES cell.

[0237] Meanwhile, the UE may be provided with the configuration for the uplink WUS requesting SIB1 for the NES cell through at least one or a combination of the following methods.

[0238] - RRC messages transmitted from Cell A (e.g., SIB1 or other system information block, RRC release message),

[0239] - DCI transmitted on Cell A or NES cell,

[0240] - Msg2 / Msg4 (in the 4-step random access process) or MsgB (in the 2-step random access process) transmitted from Cell A,

[0241] - Center frequency of PBCH / MIB / SSB transmitted on NES cell, or

[0242] - Information pre-defined / pre-configured in the specifications.

[0243] The current standard document 3GPP TS 38.213 describes the random access process and PRACH configuration as follows. For a more detailed description of the RRC parameters mentioned below, please refer to 3GPP TS 38.331.

[0244] Prior to initiation of the physical random access process, layer 1 receives a set of SS / PBCH block indices from upper layers and provides a corresponding set of RSRP measurements to the upper layers.

[0245] Prior to initiating a physical random access process, layer 1 may receive an indication from upper layers to perform a type-1 random access process or a type-2 random access process.

[0246] Before initiating a physical random access process, Layer 1 receives the following information from higher layers:

[0247] - Physical random access channel (PRACH) transmission parameters (PRACH preamble format, time resources, and frequency resources for PRACH transmission).

[0248] - Parameters for determining root sequences and their cyclic shifts within the PRACH preamble sequence set (index to logical root sequence table, cyclic shift (N CS ), and set type (unrestricted, restricted set A, or restricted set B).

[0249] From a physical layer perspective, the type-1 L1 random access procedure includes transmission of a random access preamble (Msg1) in a PRACH, a random access response (RAR) with a PDCCH / PDSCH (Msg2), and, when applicable, transmission of a PUSCH scheduled by a RAR UL grant and a PDSCH for contention resolution.

[0250] From a physical layer perspective, the type-2 L1 random access process includes transmission of a random access preamble in a PRACH and of a PUSCH (MsgA), reception of a RAR message with PDCCH / PDSCH (MsgB), and transmission of a PDSCH for contention resolution with the PUSCH scheduled by the fallback RAR UL grant, if applicable.

[0251] When a random access procedure for a UE is initiated by a PDCCH order, the PRACH transmission has the same subcarrier spacing (SCS) as the PRACH transmission initiated by higher layers.

[0252] When a UE is configured with two UL carriers for a serving cell and the UE detects a PDCCH command, the UE uses the UL / supplementary UL (SUL) indicator field value from the detected PDCCH command to determine the UL carrier for the corresponding PRACH transmission.

[0253] The physical random access procedure for a UE is triggered upon a request for PRACH transmission by higher layers or via a PDCCH command for the cell. The higher layers' configuration for PRACH transmission includes:

[0254] - Settings for PRACH transmission on the above cell.

[0255] - Preamble index, preamble SCS, PRACH target reception power P PRACH,target , if applicable, the corresponding RA-RNTI, and the PRACH resources for the cell.

[0256] - If the UE would transmit the PRACH with repetitions, N for the PRACH transmission rep preamble >1 Number of preamble repetitions.

[0257] The UE may, on the indicated PRACH resources or N rep preamble For preamble repetitions, use the same spatial filter to obtain N rep preambleOn a determined set of resources, the transmit power P as described in section 7.4 of 3GPP TS 38.214. PRACH,b,f,c (i) A UE transmits a PRACH on a cell using the selected PRACH format with transmission power P PRACH,b,f,c (i), as described in section 7.4 of 3GPP TS 38.214, on the indicated PRACH resource or on a determined set of N rep preamble resources using a same spatial filter in case of N rep preamble preamble repetitions.)

[0258] For a Type-1 random access procedure, the UE is provided with a number N of SS / PBCH block indexes associated with a PRACH occasion and a number R of contention based preambles per SS / PBCH block index per valid PRACH occasion by the RRC parameter ssb-perRACH-OccasionAndCB-PreamblesPerSSB.

[0259] For a type-1 random access procedure with a common configuration of PRACH occasions, the UE is provided with the number N of SS / PBCH block indices associated with a PRACH occasion by the RRC parameter ssb-perRACH-OccasionAndCB-PreamblesPerSSB and the number Q of contention-based preambles per SS / PBCH block index per valid PRACH occasion by the RRC parameter msgA-CB-PreamblesPerSSB-PerSharedRO. A PRACH transmission may occur on a subset of PRACH occasions associated with the same SS / PBCH block index within a SSB-RO mapping cycle for the UE provided with the PRACH mask index by the RRC parameter msgA-SSB-SharedRO-MaskIndex according to 3GPP TS 38.321.

[0260] For a Type-2 random access procedure with a separate configuration of PRACH occasions with a Type-1 random access procedure, the UE receives the number N of SS / PBCH block indices associated with a PRACH occasion and the number R of contention-based preambles per SS / PBCH block index per valid PRACH occasion, when provided, by an RRC parameter msgA-SSB-PerRACH-OccasionAndCB-PreamblesPerSSB, otherwise, ssb-perRACH-OccasionAndCB-PreamblesPerSSB.

[0261] For a random access procedure associated with a feature combination indicated by the RRC information element FeatureCombinationPreambles, which associates a feature combination with a set of preambles, the UE is provided with the number N of SS / PBCH block indices associated with one PRACH occasion by the RRC parameter ssb-perRACH-OccasionAndCB-PreamblesPerSSB or, if provided, msgA-SSB-PerRACH-OccasionAndCB-PreamblesPerSSB, and with the number S of contention-based preambles per SS / PBCH block index per valid PRACH occasion by the RRC parameter startPreambleForThisPartition and the RRC parameter numberOfPreamblesPerSSB-ForThisPartition. A PRACH transmission is performed on a PRACH mask index associated with the same SS / PBCH block index within a SSB-RO mapping cycle for a UE provided with a PRACH mask index by ssb-SharedRO-MaskIndex according to 3GPP TS 38.321. This can be done on subsets of PRACH periods.

[0262] For a type-1 random access procedure, or for a type-2 random access procedure having a separate set of PRACH occasions from the type-1 random access procedure, if N<1, one SS / PBCH block index is mapped to 1 / N consecutive valid PRACH occasions, and R contention-based preambles having consecutive indices associated with the SS / PBCH block index per valid PRACH occasion are mapped starting from preamble index 0. If N≥1, R contention-based preambles having consecutive indices associated with the SS / PBCH block index n per valid PRACH occasion are mapped to preamble index n*N. total preamble Starting from / N, 0≤n≤N-1, and Ntotal preamble is provided by totalNumberOfRA-Preambles for a type-1 random access process, or by msgA-TotalNumberOfRA-Preambles for a type-2 random access process that has a separate set of PRACH occasions from a type-1 random access process, and is an integer multiple of N.

[0263] For a type-2 random access process having a common set of PRACH epochs with a type-1 random access process, if N<1, one SS / PBCH block index is mapped to 1 / N consecutive valid PRACH epochs, and Q contention-based preambles having consecutive indices associated with the SS / PBCH block index per valid PRACH epoch start from preamble index R. If N≥1, Q contention-based preambles having consecutive indices associated with SS / PBCH block index n per valid PRACH epoch are mapped to preamble index n*N. total preamble Starting from / N + R, where 0≤n≤N-1, and N total preamble is provided by totalNumberOfRA-Preambles for type-1 random access processes.

[0264] In case of link recovery, the UE is provided with N SS / PBCH block indices associated with one PRACH occasion by the RRC parameter ssb-perRACH-Occasion in the RRC configuration BeamFailureRecoveryConfig. In case of dedicated RACH configuration provided by the RRC configuration RACH-ConfigDedicated, if parameters cfra for contention-free random access to a given target cell are provided, the UE is provided with N SS / PBCH block indices associated with one PRACH occasion by the parameter ssb-perRACH-Occasion in the parameter occasions for random access occasions for contention-free random access. If N<1, then one SS / PBCH block index is mapped to 1 / N consecutive valid PRACH occasions. If N≥1, then all N consecutive SS / PBCH block indices are associated with one PRACH occasion.

[0265] The SS / PBCH block indices provided by ssb-PositionsInBurst in SIB1 or RRC configuration ServingCellConfigCommon are mapped to valid PRACH occasions in the following order, with parameters as described in 3GPP TS 38.211.

[0266] > First, in increasing order of preamble indices within a single PRACH period.

[0267] > Second, in increasing order of frequency resource indices for frequency multiplexed PRACH periods.

[0268] > Third, in increasing order of time resource indices for time-multiplexed PRACH periods within a PRACH slot.

[0269] > Fourth, in increasing order of indexes for PRACH slots

[0270] The association period, starting from frame 0, for mapping SS / PBCH block indices to PRACH periods is N SSB Tx An association period, starting from frame 0, for mapping SS / PBCH block indexes to PRACH occasions is the smallest integer number in the set determined by the PRACH configuration period according to the following table such that N SSB Tx SS / PBCH block indexes are mapped at least once to the PRACH occasions within the association period), where the UE determines N from the value of ssb-PositionsInBurst in SIB1 or ServingCellConfigCommon. SSB Tx Get .

[0271] The following table illustrates the mapping between the PRACH configuration period and the SS / PBCH block to PRACH occasion association period.

[0272]

[0273] For a PRACH transmission by a UE triggered by a PDCCH command, if the value of the random access preamble index field is not 0, the PRACH mask index field indicates a PRACH occasion for the PRACH transmission, where the PRACH occasions are associated with the SS / PBCH block index indicated by the SS / PBCH block index field of the PDCCH command, and the cell indicator field, if any, indicates a cell for the PRACH transmission (see 3GPP TS 38.212). The UE may indicate K by the RRC parameter cellSpecificKoffset. cell,offset If provided, the PRACH period is slot n + 2 u ·K cell,offset After that, n is T TA = 0, is the slot of the UL BWP for PRACH transmission overlapping the end of the PDCCH command reception, and u is the SCS configuration for the PRACH transmission. If the PDCCH reception for the PDCCH command includes two PDCCH candidates from two linked search space sets based on the RRC parameter searchSpaceLinkingId used to link two search spaces of the same type within the same BWP, then the last symbol of the PDCCH reception is the last symbol of the later-ending PDCCH candidate, as described in section 10.1 of 3GPP TS 38.213. The above PDCCH reception includes the two PDCCH candidates even when the UE is not required to monitor one of the two PDCCH candidates as described in sections 10 (except section 10.4), 11.1, 11.1.1 and 17.2 of 3GPP 38.213.

[0274] For PRACH transmissions triggered by upper layers, if the RRC parameter ssb-ResourceList is provided, the PRACH mask index is indicated by the RRC parameter ra-ssb-OccasionMaskIndex, which indicates the PRACH occasion for the PRACH transmission.

[0275] PRACH epochs are mapped consequently for each SS / PBCH block index. The indexing of the PRACH epoch indicated by the mask index value is reset per mapping cycle of consecutive PRACH epochs for each SS / PBCH block index. The UE selects the PRACH epoch indicated by the PRACH mask index value for the indicated SS / PBCH block index for PRACH transmission within the first available mapping cycle.

[0276] For the above indicated preamble index, the ordering of PRACH epochs is

[0277] > First, for frequency multiplexed PRACH periods, in increasing order of frequency resource indices

[0278] > Second, for the time-multiplexed PRACH periods within the PRACH slot, in increasing order of time resource indices.

[0279] > Third, in increasing order of indexes for PRACH slots

[0280] N rep preamble For PRACH transmissions with multiple preamble repetitions, the set is N, which are consecutive in time and use the same frequency resources and are associated with the same one or more SS / PBCH block index(es). rep preambleIt consists of a set of valid PRACH epochs, and each SS / PBCH block index is associated with the same preamble index within all valid PRACH epochs within the set.

[0281] For PRACH transmission with preamble repetitions, the time interval starting from frame 0 is N SSB Tx For a PRACH transmission with preamble repetitions, a time period, starting from frame 0, is the smallest integer number of association pattern periods such that at least one set of valid PRACH occasions for each of the N SS / PBCH block indices can be determined within the time period for all the configured number of preamble repetitions. SSB Tx SS / PBCH block indexes can be determined within the time period for all configured preamble repetitions. The set(s) of valid PRACH occasions for each configured number of preamble repetitions repeats every time period.

[0282] Within a time interval, N rep preamble N for PRACH transmission with dog preamble repetitions rep preamble About the set of valid preamble repetitions

[0283] > The first valid PRACH epoch of the first set is the first valid PRACH epoch

[0284] > The first valid PRACH epoch of subsequent sets (if any) is determined by the ordering of the valid PRACH epochs.

[0285] >> First, in increasing order of frequency resource indices for frequency multiplexed PRACH periods.

[0286] >> Second, in increasing order of time resource indexes of time multiplexing PRACH periods

[0287] Here, for each frequency resource index for frequency multiplexed PRACH periods,

[0288] > The first valid PRACH epoch of the first set is the first valid PRACH epoch

[0289] > If any, the first valid PRACH period of the subsequent sets is

[0290] >> If the RRC parameter msg1-RepetitionTimeOffsetROGroup is provided, it is msg1-RepetitionTimeOffsetROGroup consecutive valid PRACH occasions in time from the first valid PRACH occassion of the previous set, where each PRACH occassion is associated with the same SS / PBCH block index(es) and each SS / PBCH block index is associated with the same preambles.

[0291] >> If the RRC parameter msg1-RepetitionTimeOffsetROGroup is not provided, it is after the PRACH time of the previous set.

[0292] For PRACH transmissions triggered upon request by higher layers, if the RRC parameter csi-ResourceList is provided, the value of the RRC parameter ra-OccasionList indicates a list of PRACH occasions for the PRACH transmission, where the PRACH occasions are associated with the selected CSI-RS index indicated by the RRC parameter csi-RS. The indexing of the PRACH occasions indicated by ra-OccasionList is reset for each associated pattern interval.

[0293] For paired spectrum or supplementary uplink bands, all PRACH periods are valid.

[0294] For unpaired spectra,

[0295] > If the UE is not provided with RRC configuration tdd-UL-DL-ConfigurationCommon, the PRACH timing within the PRACH slot shall not precede the SS / PBCH block within the PRACH slot and shall be at least N symbols after the last SS / PBCH block received. gap If it starts after the dog symbols, it is valid, where N gap is provided in the following table and does not overlap with the set of consecutive symbols before the start of the next channel occupancy time (see 3GPP TS 37.213) that the UE does not transmit if the RRC parameter channelAccessMode="semiStatic" is provided.

[0296] >> The candidate SS / PBCH block index of an SS / PBCH block corresponds to the SS / PBCH block index provided by ssb-PositionsInBurst in SIB1 or ServingCellConfigCommon as described in section 4.1 of 3GPP TS 38.213.

[0297] > When the UE is provided with tdd-UL-DL-ConfigurationCommon, the PRACH time within the PRACH slot is valid when:

[0298] >> If it is within the UL symbol, or

[0299] >> It does not precede the SS / PBCH block within the above PRACH slot and is at least N blocks after the last downlink symbol. gap After the dog symbols and after the last SS / PBCH block symbol, at least N gap Starting after the dog symbols, here N gap is provided in the following table, and if channelAccessMode = "semiStatic" is provided, it does not overlap with the set of consecutive symbols before the start of the next channel occupancy time during which there shall be no transmissions (it does not precede a SS / PBCH block in the PRACH slot and starts at least N gap symbols after a last downlink symbol and at least N gap symbols after a last SS / PBCH block symbol, where N_gap is provided in Table 8.1-2, and ifchannelAccessMode= "semiStatic" is provided, does not overlap with a set of consecutive symbols before the start of a next channel occupancy time where there shall not be any transmissions, as described in 3GPP TS 37.213.

[0300] >>> The candidate SS / PBCH block index of the above SS / PBCH block corresponds to the SS / PBCH block index provided by ssb-PositionsInBurst in SIB1 or ServingCellConfigCommon as described in section 4.1 of 3GPP TS 38.213.

[0301] The following table shows N for different preamble SCS u gap Here are some examples of values.

[0302]

[0303] For preamble format B4 described in 3GPP TS 38.211, N gap = 0.

[0304] When a random access procedure is initiated by a PDCCH command, the UE transmits a PRACH within the selected PRACH period as described in 3GPP TS 38.321, if requested by upper layers, wherein the time between the last symbol of PDCCH command reception and the first symbol of the PRACH transmission is N T,2 + T BWPswitchDelay + △ Delay + T switch + T SSB + △RF / BB preparationmsec is greater than or equal to, where

[0305] > N T,2 is a time duration of N2 symbols corresponding to the PUSCH preparation time for UE processing capability 1 (see 3GPP TS 38.214), assuming u corresponds to the smallest SCS setting among the SCS setting of the PDCCH command and the SCS setting of the corresponding PRACH transmission.

[0306] > If the active UL BWP does not change or the cell indicator field in the PDCCH command indicates a non-serving cell, T BWPswitchDelay= 0, otherwise T BWPswitchDelay is defined in 3GPP TS 38.133

[0307] > About FR1 △ Delay = 0.5 msec and △ for FR2 Delay = 0.25 msec

[0308] > T switch is the switching gap duration as defined in 3GPP TS 38.214

[0309] > The cell indicator field in the above PDCCH command indicates the serving cell or T if the cell indicator field does not exist. SSB = 0, otherwise T SSB is defined in 3GPP TS 38.133

[0310] > If the cell indicator field in the above PDCCH command indicates a serving cell or the cell indicator field does not exist, △RF / BB preparation = 0, otherwise △RF / BB preparation is defined in 3GPP TS 38.133.

[0311] For PRACH transmission using 1.25 kHz or 5 kHz SCS, the UE determines N2 assuming SCS setting u = 0.

[0312] For single cell operation or operation with contiguous carrier aggregation in the same frequency band or operation with non-continuous carrier aggregation in the same frequency band if the UE is not provided with intraBandNC-PRACH-simulTx-r17, the UE shall:

[0313] > Does not transmit PRACH and PUSCH / PUCCH / SRS in a same slot with respect to the smallest SCS configuration between the SCS configuration for the UL BWP with the PRACH and the SCS configuration for the UL BWP with the PUSCH / PUCCH / SRS transmissions.

[0314] > If the first or last symbol of a PRACH transmission in the first slot is separated by less than N symbols from the last or first symbol of a PUSCH / PUCCH / SRS transmission in the second slot, respectively, the PRACH and PUSCH / PUCCH / SRS are not transmitted.

[0315] > N rep preamble For a PRACH transmission with >1 preamble repetitions, if the UE does not indicate prach-repetition, the UE does not transmit the first repetition of the PRACH and the second repetition of the PRACH if the first or the last symbol of the first repetition of the PRACH in the first slot is separated by less than N symbols from the last or the first symbol of the second repetition of the PRACH in the second slot, respectively; otherwise, the UE transmits the first repetition of the PRACH and the second repetition of the PRACH.

[0316] Here, N=2 for u=0 or u=1, N=4 for u=2 or u=3, N=16 for u=5, and N=32 for u=6, where u is the smallest SCS setting among the SCS settings for UL BWP with PRACH and the SCS settings for UL BWP with PUSCH / PUCCH / SRS transmissions. For PUSCH transmissions with repetition type B, this applies to each actual repetition for the PUSCH transmission.

[0317] BSs can achieve energy saving (ES) through symbol muting when there is no data to transmit. However, common signals / channels such as SSB and SIB are always-on signals / channels that must be transmitted at all times, making it difficult to achieve ES through symbol muting in these symbols. In NR, SSB / SIB can be transmitted by beam sweeping through a specific subcarrier spacing (SCS) and multiple beams depending on the frequency range (FR). As the FR increases, the number of beams increases, and accordingly, the amount of time resources used for transmitting common signals / channels such as SSB / SIB1 in FR2 becomes relatively larger than in FR1, which can also increase the proportion of BS energy consumption. To reduce energy consumption due to constant signal transmission such as SSB / SIB of BS, the period of SSB / SIB can be set to long, but this may increase the time taken for UE to access the cell and may cause problems such as legacy UEs not being able to properly discover the cell.

[0318] Meanwhile, the UE is configured with the information required to transmit a PRACH (e.g., information about time / frequency resources) through the BS's SIB1 or UE-specific RRC signaling, and can transmit the PRACH at RACH occasions (ROs) determined / configured based on the information, and the BS must wake up for each RO and wait for PRACH reception to receive the PRACH that the UE may transmit. Therefore, if the period of the ROs configured for the UE is short, the energy consumption of the BS may be relatively greater than when the period of the ROs is set to be long. However, if the ROs are configured with an excessively long period for the purpose of saving the BS's energy, if there are no RO resources near the time when the UE needs to transmit a PRACH for cell access, the UE may have to wait until the next RO resource becomes available before transmitting, which may increase the access delay, and this may lead to a scheduling delay, which may degrade the performance of the UE.

[0319] In addition, the BS can save energy by switching to sleep mode when the number of connected mode UEs is small or there is a time period with no data activity temporarily depending on the situation in the cell. However, since the BS must wake up frequently to check for PRACH transmitted by UEs in the RO configured in the cell periodically and receive, it cannot stay in sleep mode for a long time and it is difficult to expect a large energy saving benefit. Therefore, in such cases, setting a long RO periodicity may be advantageous in terms of BS energy saving. However, according to the current standard, only semi-static methods (such as SI modification) are possible to change the settings such as the cell RO periodicity, which takes a relatively long time and may make it difficult to quickly respond to opportunities for energy saving.

[0320] Taking this into account, some implementations of this specification may perform common channel adaptation to adjust the density and / or periodicity of a common channel (e.g., SSB and / or PRACH) at the request of the BS or UE.

[0321] Below, some implementations of this specification regarding common channel adaptation are described. Below, some implementations of this specification are described that set a point in time or a period of time during which the BS or UE can expect transmission / reception of the (initially) adapted common channel after adaptation of the common channel (e.g., SSB, PRACH, etc.) is triggered or requested by the BS or UE.

[0322] In order to ensure that the UE's connection delay is not too long while still achieving some energy saving benefits for the BS, some implementations of this specification consider providing a default RO configuration (relatively sparse ROs) for legacy UEs and configuring additional ROs for NES UEs (e.g., UEs supporting the NES feature). Hereinafter, ROs for UEs supporting the NES feature or UEs requiring additional ROs for other reasons are referred to as additional ROs, and the configuration for at least one additional RO is referred to as a NES_RO configuration. In this specification, the configuration for additional ROs is referred to as NES_RO for convenience of explanation, but the additional ROs configured by some implementations of this specification are not limited to NES technologies.

[0323] In some implementations of this specification, the NES_RO configuration may be provided together with the default RO configuration or may be provided separately. In some implementations, RO for legacy UEs may mean RO resources for the 4-phase random access procedure of 3GPP Release-15, RO resources for the 2-phase random access procedure of 3GPP Release-16, RO resources for reduced capability (Redcap) UEs of 3GPP Release-17, or RO resources for coverage enhancement (CE) of 3GPP Release-18. There may be one or more NES RO configurations. Different RO patterns / periodicity, etc. may be configured for each NES RO configuration, and NES UEs may be activated through a pre-configured / defined index, or switching between NES RO configurations may be instructed if there is an NES RO configuration that is already activated. One or more NES RO settings may be provided via SIB1, similar to the default RO settings, or may be configured via other RRC signaling.

[0324] The NES UE can be configured by the BS to use only the NES RO among the ROs configured, or to use both the default RO and the NES RO. If there is no separate configuration for this, the NES UE can interpret that both the default RO and the NES RO are configured to be available. Even when the NES UE is configured to use both the default RO and the NES RO, the NES RO is normally deactivated and all UEs (e.g., both legacy UEs and NES UEs) can use only the default RO, and the NES RO can be activated by a dynamic instruction from the BS (upon the request of the UE). Alternatively, when the activation (deactivation) of the NES RO is indicated, the activation (deactivation) of the default RO may be indicated together or separately.

[0325] Below, some implementations of this specification are described using PRACH / MsgA PRACH as an example of an UL signal for a UE to request adaptation of a common channel (e.g., SSB, PRACH, etc.) to a BS, but other UL signals (e.g., (semi-static (SP)-)PUCCH / SRS / (CG-)PUSCH) can also be used as an UL signal for common channel adaptation request.

[0326] <Method #1> After the UE requests SSB / PRACH adaptation through a specific UL signal, the time point at which the UE can receive / transmit SSB / PRACH of the (first) changed period it expects (hereinafter, time instance A1)

[0327] > A. T ms / slots after UL WUS / Msg3 transmission

[0328] > B. From T1 ms / slots to T2 ms / slots after the UL WUS / Msg3 transmission time.

[0329] > C. Monitoring occasion (MO) / RACH occasion (RO) for receiving / transmitting SSB / PRACH of changed cycle after UL WUS / Msg3 transmission time

[0330] >> i. (Assuming that the SSB / PRACH periodicity to be changed is P, the SSB / PRACH MO / RO based on P is known to the UE) The first SSB / PRACH MO / RO after T ms / slots from the time of UL signal transmission

[0331] >> ii. (Assuming that the SSB / PRACH cycle to be changed is P, the SSB / PRACH MO / RO based on P is known to the UE) SSB / PRACH MO / RO belonging to the time interval from T1 ms / slots to T2 ms / slots after the UL signal transmission time.

[0332] > D. A method in which a separate UL signal may be set for each of the multiple SSB / PRACH periodicity candidates or a single UL signal may be set, and in the latter case, a method of indicating or requesting the SSB / PRACH periodicity through Msg3.

[0333] The UE can expect reception / transmission of SSB / PRACH of a changed period after transmitting a SSB / PRACH adaptation request by transmitting a UL signal (e.g., Msg1 / MsgA PRACH) that has been previously agreed / configured to the BS. At this time, the UE can be configured by the BS with a time point (e.g., T ms / slots or T1 ms / slots after the UL signal is transmitted) or a period (e.g., T2 ms / slots starting from T1 ms / slots after the UL signal is transmitted) at which reception / transmission of SSB / PRACH of a (first) changed period can be expected. The UE can attempt reception or transmission of SSB or PRACH of a changed period after the configured reception time point (e.g., T or T1) or within the period (e.g., T2).

[0334] Alternatively, a time point (e.g., T ms / slots or T1 ms / slots after the UL signal transmission time point) or period (e.g., T2 ms / slots starting from T1 ms / slots after the UL signal transmission time point) at which transmission / reception of SSB / PRACH MO / RO of a changed cycle can be expected may be set. A UE that has received the setting may attempt to receive / transmit SSB in the first SSB / PRACH MO / RO after T ms / slots from the UL signal transmission time point (assuming the SSB / PRACH period is P and the SSB / PRACH MO / RO based on P is known to the UE), or may attempt to receive / transmit SSB / PRACH MO / RO in the time interval from T1 ms / slots to T2 ms / slots after the UL signal transmission time point (assuming the SSB / PRACH period is P and the SSB / PRACH MO / RO based on P is known to the UE).

[0335] When the UE triggers adaptation of SSB / PRACH (e.g., requests adaptation to the BS via an UL signal), a separate UL signal may be configured in advance for each of the multiple SSB / PRACH period candidates. Alternatively, a single UL signal may be configured for the multiple SSB / PRACH period candidates, in which case the UE may indicate one of the multiple SSB / PRACH periods by including the SSB / PRACH period information requested from the BS via a subsequent additional / follow-up UL signal (e.g., Msg3).

[0336] In Method #1, T / T1 / T2 can be based on the first / last symbol of the UL (WUS) signal, or the first / last symbol of the slot in which the UL (WUS) signal is transmitted. Here, T / T1 / T2 can be set not only at the ms / slot level but also at the symbol level.

[0337] <Method #2> The time point (hereinafter, time instance A1') when the UE can receive (GC-)DCI / MAC-CE indicating (first) SSB / PRACH adaptation expected by the UE after the UE requests SSB / PRACH adaptation through a specific UL signal.

[0338] > A. T ms / slots after UL signal transmission time

[0339] > B. From T1 ms / slot to T2 ms / slot after the UL signal transmission time.

[0340] > C. (Group common) DCI ((group common) DCI, (GC-)DCI) (or MAC control element (MAC control element, MAC-CE) MO) indicating SSB / PRACH adaptation after UL signal transmission time

[0341] >> i. (The (GC-)DCI (or MAC-CE) MO indicating SSB / PRACH adaptation is the first (GC-)DCI (or MAC-CE) MO after T ms / slots from the time of UL signal transmission, with the UE knowing it)

[0342] >> ii. (GC-)DCI (or MAC-CE) MO indicating SSB / PRACH adaptation, in the time interval from T1 ms / slots to T2 ms / slots after the UL signal transmission time, with the UE knowing)

[0343] After a UE transmits a SSB / PRACH adaptation request to a BS by transmitting a pre-arranged / configured UL signal (e.g., Msg1 / MsgA PRACH), the UE may receive an instruction to change the actual SSB / PRACH cycle through (GC-)DCI / MAC-CE for a response to the request and an adaptation instruction from the BS. At this time, the BS that receives the request from the UE must determine whether actual SSB / PRACH adaptation is necessary. Therefore, the UE may not always be able to receive a response and an adaptation instruction from the BS every time it requests adaptation, and the BS may simply convey to the UE only information that the UL WUS has been successfully received. For example, the BS may instruct the UE to maintain the current SSB / PRACH cycle.

[0344] After requesting adaptation to the BS via an UL signal, the UE may be configured with a time point (e.g., T ms / slots or T1 ms / slots after transmission of the UL signal) or a period (e.g., T2 ms / slots starting from T1 ms / slots after transmission of the UL signal) at which it can expect to receive an (initial) SSB / PRACH adaptation indication from the BS in order to receive a response to the UL signal. The UE may attempt to receive the SSB / PRACH adaptation indication after the time point of reception of the setting or within the period.

[0345] Alternatively, the time point (e.g., T ms / slots or T1 ms / slots after transmission of the UL signal) or the period (e.g., T2 ms / slots starting from T1 ms / slots after transmission of the UL signal) at which reception of a (GC-)DCI (or MAC-CE) MO indicating SSB / PRACH adaptation can be expected after transmission of the UL signal may be set.

[0346] In Method #2, T / T1 / T2 can be based on the first / last symbol of the UL (WUS) signal, or based on the first / last symbol of the slot in which the UL (WUS) signal is transmitted, and wherein T / T1 / T2 can be set / indicated at the slot level as well as the ms / slot level. Alternatively, in Method #2, T / T1 / T2 can be based on the first / last symbol of the Msg2 / ACK / (GC-)DCI / MAC-CE signal, or based on the first / last symbol of the slot in which the Msg2 / ACK / (GC-)DCI / MAC-CE signal is received, and wherein T / T1 / T2 can be set / indicated at the slot level as well as the ms / slot level. In particular, for Msg2, the first / last symbol of the CORESET containing the Msg2 DCI can be used as a reference, and for (GC-)DCI, the first / last symbol of the CORESET containing the DCI can be used as a reference.

[0347] <Method #3> Changed SSB / PRACH reception / transmission time expected by UE after receiving Msg2 / ACK / GC-DCI / MAC-CE from BS (hereinafter, time instance A2)

[0348] > A. T ms / slots after receiving Msg2 / ACK / GC-DCI / MAC-CE

[0349] > From T1 ms / slots to T2 ms / slots after receiving Msg2 / ACK / GC-DCI / MAC-CE

[0350] > B. MO / RO receiving / transmitting SSB / PRACH of changed cycle after receiving Msg2 / ACK / GC-DCI / MAC-CE

[0351] >> i. (Assuming that the SSB / PRACH cycle to be changed is P, the SSB / PRACH MO / RO based on P is known to the UE) The first SSB / PRACH MO / RO after T ms / slots from the time of receiving Msg2 / ACK / GC-DCI / MAC-CE

[0352] >> ii. (Assuming that the SSB / PRACH cycle to be changed is P, the SSB / PRACH MO / RO based on P is known to the UE) SSB / PRACH MO / RO within the time interval from T1 ms / slots to T2 ms / slots after the time of receiving Msg2 / ACK / GC-DCI / MAC-CE

[0353] >> C. Method #1: In the determination of time instance A1, candidates for T / T1 / T2 values ​​are set in advance, and one of the values ​​is set / indicated by BS signaling (e.g., Msg2 / ACK / GC-DCI / MAC-CE).

[0354] >> D. A method in which one of the multiple SSB / PRACH cycle candidates set to the UE in advance is directly set / indicated through Msg2 / ACK / GC-DCI / MAC-CE.

[0355] The BS, which has received the UL WUS of the UE, can transmit Msg2 / ACK / GC-DCI / MAC-CE to the UE as a response to the successful reception of the UL WUS. Method #3 is a method that replaces the UL WUS / Msg3 transmission time in the determination of time instance A1 of Method #1 with the Msg2 / ACK / GC-DCI / MAC-CE reception time, and the UE can set T / T1 / T2 based on the Msg2 / ACK / GC-DCI / MAC-CE reception time and attempt reception / transmission of SSB / PRACH MO / RO. In addition, multiple candidates for T / T1 / T2 values ​​may be set in advance from the BS, and one of the values ​​may be indicated as Msg2 / ACK / GC-DCI / MAC-CE. Additionally, when the BS triggers adaptation of SSB / PRACH, one of the multiple SSB / PRACH cycle candidates previously configured to the UE may be directly configured / indicated via Msg2 / ACK / GC-DCI / MAC-CE.

[0356] In Method #3, T / T1 / T2 can be based on the first / last symbol of the UL (WUS) signal, or based on the first / last symbol of the slot in which the UL (WUS) signal is transmitted / received, and T / T1 / T2 can be set / indicated at symbol-level as well as ms / slot level. Or in Method #3, T / T1 / T2 can be based on the first / last symbol of the Msg2 / ACK / (GC-)DCI / MAC-CE signal, or based on the first / last symbol of the slot in which the Msg2 / ACK / (GC-)DCI / MAC-CE signal is received / transmitted, and T / T1 / T2 can be set / indicated at symbol-level as well as ms / slot level. In particular, for Msg2, the first / last symbol of the CORESET containing the Msg2 DCI can be used as a reference, and for (GC-)DCI, the first / last symbol of the CORESET containing the DCI can be used as a reference.

[0357] In some implementations, the SSB / PRACH reception / transmission time window of the changed period may start from a preset (time) offset or a (time) offset dynamically indicated by the BS with respect to the time determined by T / T1 / T2 (hereinafter, referred to as reference time for convenience), for example, from the point in time of the reference time + (time) offset (e.g., from the point in time after the (time) offset after the reference time). Alternatively, the SSB / PRACH reception / transmission time window of the changed period may start from the first / last symbol of the earliest CORESET / RO configured for SSB / PRACH reception / transmission of the changed period from the point in time of the reference time + (time) offset (e.g., from the point in time after the (time) offset after the reference time). In this case, the MO / RO in which the SSB / PRACH of the changed period is received / transmitted may mean one of the following:

[0358] > Option 1) MO / RO where SSB / PRACH in the beam direction linked to the UL WUS (beam) direction transmitted by the UE is received / transmitted, or

[0359] > Option 2) MO / RO where the fastest SSB / PRACH is received / transmitted regardless of the UL WUS (beam) direction transmitted by the UE, or

[0360] > Option 3) MO / RO in which the first SSB / PRACH corresponding to the first actually transmitted SSB index is received / transmitted by the BS (in some implementations, the actually transmitted SSB indices may be signaled by the parameter ssb-PositionsInBurst, and the first actually transmitted SSB index may mean the SSB index set to be the indicated first SSB index to be actually transmitted via the signaling), or

[0361] > Option 4) MO / RO where the first SSB / PRACH corresponding to candidate SSB index #0 is received / transmitted

[0362] Meanwhile, according to section 8.2 of the current 3GPP TS 38.213, the RAR window starts from the first symbol of the earliest CORESET configured to receive a PDCCH for a Type1-PDCCH CSS set, which is at least one symbol after the last symbol of the PUSCH epoch corresponding to the PRACH transmission, where the symbol period corresponds to the subcarrier spacing for the Type1-PDCCH CSS set. A Type-1 PDCCH CSS set is a search space set for transmission of a DCI format scrambled with RA-RNTI, MsgB-RNTI, or TC-RNTI on a primary cell, and a UE may monitor a Type-1 PDCCH CSS set during a random access procedure, and may perform PDCCH monitoring according to a Type-1 PDCCH CSS set to receive a DCI (hereinafter, Msg2 / Msg4 / MsgB DCI) scheduling a PDSCH carrying Msg2 or MsgB (hereinafter, Msg2 / MsgB PDSCH) or a PDSCH carrying Msg4 (hereinafter, Msg4 PDSCH). According to the current standard, an RAR window starts from the first symbol of a CORESET associated with the earliest Type-1 PDCCH CSS set that is at least one symbol after the last symbol of a PRACH epoch, and the length of the RAR window is determined by the RRC parameter ra-ResponseWindow.However, since the DCI scheduling Msg2 or MsgB (hereinafter, Msg2 / MsgB DCI) may not actually be transmitted from the CORESET corresponding to the start point of the RAR window, the reference point for T / T1 / T2 may mean one of the following: 1) the first / last symbol of the UL WUS signal from the UE; or 2) the start / end of the RAR window (if Msg2 / MsgB DCI is found); or 3) the first / last symbol of the CORESET in which Msg2 / MsgB DCI is received (if Msg2 / MsgB DCI is found); or 4) the first / last symbol of the Msg2 / MsgB PDCCH / PDSCH (if Msg2 / MsgB DCI is found); Or 5) the first / last symbol of the slot containing the signal / channel of 1) / 2) / 3) / 4) (e.g., in case of 1), the first / last symbol of the slot in which UL WUS is transmitted, in case of 2), the first / last symbol of the slot to which the start / end of the RAR window belongs (if Msg2 / MsgB DCI is found), in case of 3), the first / last symbol of the slot containing the CORESET in which Msg2 / MsgB DCI is received (if Msg2 / MsgB DCI is found), in case of 4), the first / last slot of the slot containing Msg2 / MsgB PDCCH / PDSCH (if Msg2 / MsgB DCI is found).

[0363] If there is only a single candidate for the time window-related parameters for receiving / transmitting SSB / PRACH of a changed period, the starting point of the time window may be determined by applying an offset previously set by a higher layer signal such as RRC (e.g., assuming that the processing time = 0) to the reference point. In some implementations, if there are multiple candidates for the time window-related parameters for receiving / transmitting SSB / PRACH of a changed period and one of them is indicated by an RAR used as a response to an UL WUS, the processing time of the RAR may be taken into account, and a point in time after the RAR reception that has elapsed the processing time may be determined as the starting point of the time window.

[0364] <Method #4> How to perform PDCCH monitoring of UE during random access process when additional SSB / RO can be dynamically activated / deactivated based on DCI

[0365] For example, if an additional SSB / RO for NES is configured and activated for a UE, the UE can transmit a PRACH through the additional RO. However, if the deactivation of the additional RO is suddenly indicated by a DCI during the random access (RA) process, the UE may need to perform a retransmission through RO resources / parameters (e.g., RA preamble) different from the RO configuration selected by the UE in the initial PRACH transmission. Therefore, the UE needs to monitor the DCI indicating the activation / deactivation of the additional SSB / RO even during the RA process.

[0366] For example, in the MAC standard (e.g., 3GPP TS 38.321), the UE can perform PDCCH monitoring during the RA procedure in the following cases: 1) PDCCH monitoring with RA-RNTI while the RAR window is running, 2) PDCCH monitoring for TC-RNTI or C-RNTI while the contention resolution (CR) timer is running. In 3GPP TS 38.213, with respect to the RACH procedure, the search space sets and associated RNTIs that the UE should monitor during the RA procedure are described as follows: a Type0A-PDCCH CSS set configured by searchSpaceOtherSystemInformation in PDCCH-ConfigCommon for DCI format 1_0 with CRC scrambled by SI-RNTI on the primary cell of the master cell group (MCG). bysearchSpaceOtherSystemInformationinPDCCH-ConfigCommonfor a DCI format 1_0 with CRC scrambled by a SI-RNTI on the primary cell of the MCG), a Type1-PDCCH CSS set configured by ra-SearchSpace in PDCCH-ConfigCommon for a DCI format with CRC scrambled by a RA-RNTI, a MsgB-RNTI, or a TC-RNTI on the primary cell.

[0367] Accordingly, in some implementations, if a specific DCI format, RNTI, and / or search space set indicating activation / deactivation of additional SSB / RO is defined, an RNTI in a DCI format indicating activation (deactivation) of additional SSB / RO may be added to the search space set that the UE should monitor during the RA process as exemplified above, or a search space set for PDCCH monitoring indicating activation (deactivation) of additional SSB / RO may be additionally configured as one of the search space sets that the UE should monitor during the RA process.

[0368] <Method #5> A method of declaring a failure when an SSB with a changed period is not received from time instance A1 or A2 for a certain period of time, and not transmitting additional UL WUS for a certain period of time.

[0369] If the UE does not receive an SSB of a changed period from time instance A1 or A2 for a certain period of time after T / T1 / T2 set according to the aforementioned method #1 or method #3, i) after transmitting a specific UL signal or ii) after receiving Msg2 / ACK / GC-DCI / MAC-CE as a response to said UL signal, the UE may declare a failure and may be configured not to transmit any further UL signal for the certain period of time, similar to the prohibit timer of a scheduling request (SR). At this time, the duration and prohibit timer values ​​for when a failure is declared when no SSB reception of the changed period has occurred from the configured time point (e.g., time instance A1 or A2) may be defined in the standard or preset (e.g., via UL resource configuration for adaptation request), and in the case of time instance A2, one of multiple preset duration / timer values ​​may be directly indicated via Msg2 / ACK / GC-DCI / MAC-CE. Meanwhile, if T2 ms / slots / symbols are configured according to Method #1 or Method #3, failure may be declared immediately after T2 (e.g., after a period of T2 has elapsed after time T1 has elapsed from Msg2 / ACK / GC-DCI / MAC-CE reception / transmission).

[0370] <Method #6> A method of declaring failure when (GC-)DCI / MAC-CE indicating SSB / PRACH adaptation is not received from time instance A1 for a certain period of time, and not transmitting additional UL WUS for a certain period of time.

[0371] Similar to Method #4, after the UE transmits a specific UL signal requesting SSB / PRACH adaptation to the BS, if no (GC-)DCI / MAC-CE indicating SSB / PRACH adaptation is received for a set period of time, similar to Method #2, a failure is declared, and similar to the prohibit timer of a scheduling request (SR), no additional UL signal transmission can be set for the set period of time. The duration and prohibit timer values ​​for when failure is declared when no (GC-)DCI / MAC-CE indicating SSB / PRACH adaptation is received from the configured time point can be defined in the standard or preset (e.g. via UL resource configuration for adaptation request), and if T2 ms / slots / symbol is configured, the UE can also declare failure immediately after T2 (e.g. after a period of T2 after a specific UL signal requesting SSB / PRACH adaptation has elapsed since the transmission of the specific UL signal requesting SSB / PRACH adaptation).

[0372] <Method #7> A method for determining the time instance B when receiving / transmitting the changed SSB / PRACH after time instance A1 or A2 and then receiving / transmitting up to time instance B.

[0373] > A. A method of determining based on a timer (or time window) or N-time SSB / PRACH periodicity (here, the period of PRACH may mean a PRACH configuration period, an association (pattern) period, and / or an SSB-to-RO mapping cycle, etc.)

[0374] >> i. The timer / time window / N value is defined / set in advance or one of multiple pre-set candidate values ​​is set / instructed by the BS.

[0375] > B. How BS directly sets / instructs SSB / PRACH off (i.e., deactivates)

[0376] > C. How a UE requests SSB / PRACH off (e.g., deactivation)

[0377] > D. SSB / PRACH off in B or C above may mean turning off additional SSB / PRACH for NES UE or falling back to default SSB / PRACH period.

[0378] To aid in understanding some implementations of this specification, the PRACH settings according to the current standard document are first described with reference to the following table and Figure 19.

[0379] The following table illustrates random access configurations. In particular, the table is part of Table 6.3.3.2-4, which defines random access configurations for FR2 and unpaired spectrum, as described in 3GPP TS 38.211.

[0380]

[0381] The table above is a mother table for indicating a PRACH configuration index in 3GPP TS 38.211, and the UE determines an appropriate table based on the frequency range and whether it is frequency division duplex (FDD) or time division duplex (TDD) from SIB1, and is instructed to indicate one row index within the determined table to configure RACH slots and ROs.

[0382] Figure 19 illustrates examples of random access channel (RACH) slots and RACH occasions (ROs) according to physical random access channel (PRACH) configurations. In particular, Figure 19 illustrates RACH slots and ROs when PRACH configuration index 9 is provided through RACH configuration for cells on FR2 and unpaired spectrum.

[0383] Referring to Table 8 and Figure 19, if PRACH setting index = 9 based on Table 8 is provided, first n f The periodicity of the RO in the SFN unit in the time domain is determined through mod x = y. Since (x, y) = (2, 1), there can be an RO for every odd SFN with a period of 20 ms, and the RACH slot within the frame of the corresponding SFN is set / determined through the slot number.

[0384] Figures 20 and 21 illustrate the adjustment of ROs according to some implementations of the present specification. In Figures 20 and 21, "ON" indicates that the corresponding RACH configuration is activated, and "OFF" indicates that the corresponding RACH configuration is deactivated. In Figures 20 and 21, each of "A" and "B" is an index to a row in a PRACH configuration table, and "A" and "B" may be based on the same PRACH configuration table or may be based on different PRACH configuration tables. Figures 20 and 21 illustrate a case where two PRACH configuration indices are provided for a cell, and one or more PRACH configuration indices may be provided for a cell.

[0385] In some implementations of this specification, the UE may be configured with a default RO and a NES RO through multiple PRACH configuration indices within a single PRACH configuration, or through separate PRACH configurations that may have different PRACH configuration indices. For example, the BS may provide a first PRACH configuration index for the default RO and a second PRACH configuration index for the NES RO in a single RACH configuration, or may provide a RACH configuration for the default RO that includes the first PRACH configuration index for the default RO and a PRACH configuration for the NES RO that includes the second PRACH configuration index for the NES RO. A UE provided with the first PRACH configuration index and the second PRACH configuration index may determine the ROs based on which of the activated PRACH configuration index(es) is(are) among the first PRACH configuration index and the second PRACH configuration index. Referring to FIG. 20, a UE configured with PRACH configuration index = A and PRACH configuration index = B may determine ROs for a cell according to an activated PRACH configuration among the PRACH configurations corresponding to PRACH configuration index = A and PRACH configuration index = B. In some implementations, at least one of the multiple PRACH configurations for the cell may be a PRACH configuration that is always active, and the remaining PRACH configurations may be PRACH configurations that are activated or deactivated via (GC-)DCI or MAC-CE or RRC. In some implementations, PRACH configuration unit RO adaptation may be performed in the above-described manners.

[0386] Figure 22 illustrates an association interval according to the number of SSBs per RACH period. The association interval is N given by ssb-PositionsInBurst in SIB1 or ServingCellConfigCommon. SSB TXis the minimum period (e.g., minimum number of PRACH configuration periods) required to map the SSB indices to valid PRACH occasions at least once. In the example of Fig. 22, it is assumed that the number of time domain ROs within 10 ms = 1, the number of frequency domain ROs = 4, and the number of actually transmitted SSBs = 6. In this case, referring to Fig. 22(a), the association period for ssb-perRACH-Occasion = 1 is 20 ms, and referring to Fig. 22(b), the association period for ssb-perRACH-Occasion = 2 is 10 ms. The BS can perform RO adaptation on a per-association basis (e.g., per-association basis) by instructing to activate (release) ROs within the association period for a specific RO (e.g., an additional RO).

[0387] Figure 24 illustrates the association pattern interval and SSB-to-RO mapping considering the valid RACH period.

[0388] An association pattern period includes one or more association periods and is determined so that a pattern between PRACH occasions (i.e., RO occasions) and SS / PBCH blocks repeats at most every 160 msec. An association pattern period may be N due to a TDD pattern or from the SSB or the last DL symbol in a PRACH slot. gapThis was introduced to reduce the computational complexity for SSB-to-RO mapping, since the number of ROs within the association interval may not be constant when an invalid RO occurs due to the condition that there will be a number of ROs after the dog symbols. For example, if the UE performs RO validation or SSB-to-RO mapping every time, the complexity of the UE would be too large. Therefore, an association pattern interval can be used to repeatedly apply the mapping relationship to reduce the complexity of the UE.

[0389] Referring to FIG. 24, for example, if the number of time domain ROs within 10 ms = 4, the number of frequency domain ROs = 1, and the number of actually transmitted SSBs = 3, then in SFN #0 the association interval = 10 ms, but since the number of valid ROs in SFN #1 is only 2, a 20 ms annual interval is required for 3 SSBs to be mapped at least once to valid ROs within the association interval. Therefore, in the example of FIG. 24, in order for the mapping pattern between RACH epochs and SSB indices to repeat, the annual interval pattern must include an annual interval of 10 ms and an association interval of 20 ms, and thus the annual interval pattern is 30 ms. The BS can perform RO adaptation on a per-unit basis (e.g., per-association pattern interval basis) by instructing to activate (deactivate) ROs within the association pattern interval for a specific RO (e.g., an additional RO).

[0390] Referring to Fig. 24, when the association interval is 10 ms, the SSB-to-RO mapping is performed once within the 10 ms association interval, but when the number of available ROs is sufficient, such as in SFN #1 and SFN #2 where the association interval is 20 ms, all SSB indices #0, #1, and #2 for the number of actually transmitted SSBs = 3 can be mapped twice within the association intervals of SFN #1 and SFN #2. Therefore, when there are N SSB-to-RO mapping cycles within the association interval, the BS can adapt the RO in units of SSB-to-RO mapping cycles by instructing to use or not use only specific M.

[0391] When a BS that has been transmitting / receiving SSB / PRACH with a long cycle to save energy starts transmitting / receiving SSB / PRACH with a relatively short cycle at the request of a UE, it is necessary to set how long the short-cycle SSB / PRACH transmission / reception will continue. When the UE receives from the BS the reception / transmission time point (e.g., time instance A1 or A2) and the timer (or time window) or the value N of the changed SSB / PRACH according to Method #1 or Method #3, the UE may assume that the SSB / PRACH can be received / transmitted at the pre-configured / indicated period while the timer is running from time instance A1 or A2 (or within the time window) or for N SSB / PRACH periods, and may attempt to receive and transmit the SSB / PRACH, and may assume / expect that the SSB / PRACH reception / transmission is no longer possible at the pre-configured / indicated period after the timer expires (or after the time window ends) or after N SSB / PRACH periods have elapsed. Here, the "PRACH period" may mean one of the PRACH configuration period, the association (pattern) period, and / or the SSB-to-RO mapping cycle described above. At this time, the timer, time window, and / or N value may be predefined / set or one of multiple predefined candidate values ​​may be set / indicated by the BS (e.g., via Msg2 / ACK / GC-DCI / MAC-CE / separate PDCCH).

[0392] Alternatively, when a UE requests SSB / PRACH adaptation, reception and transmission of short-period SSB / PRACH may be possible until the BS directly configures / indicates a shorter-period SSB / PRACH off (e.g., deactivation), in which case time instance B may be configured by T / T1 / T2 similar to how time instance A1 or A2 is determined in Method #1 or Method #3. Alternatively, after receiving the SSB / PRACH adaptation requested by the UE, the UE may directly request the BS to configure a short-period SSB / PRACH off (e.g., deactivation), in which case time instance B may be configured by T / T1 / T2 similar to how time instance A1 or A2 is determined in Method #1 or Method #3.

[0393] Methods #1 to #7 may be applied independently or two or more may be applied together.

[0394] According to some implementations of this specification, adaptation of a common channel (e.g., SSB and / or PRACH) may be triggered by a BS or a UE, and a time point or period may be set after which transmission / reception of the (initially) adapted common channel can be expected after common channel adaptation is indicated or requested. Accordingly, the UE can transmit / receive in an SSB / PRACH cycle aligned with the BS.

[0395] Some implementations of this specification can switch between sparser or longer-duration SSB / PRACH and dense or shorter-duration SSB / PRACH depending on network or cell conditions. Some implementations of this specification can perform SSB / PRACH adaptation quickly.

[0396] FIG. 25 illustrates a flow of downlink (DL) signal reception in a UE according to some implementations of the present specification.

[0397] A UE may perform operations according to some implementations of the present disclosure in connection with DL signal transmission. The UE may include at least one transceiver; at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations according to some implementations of the present disclosure. A processing device for the UE may include at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations according to some implementations of the present disclosure. A computer-readable (non-transitory) storage medium may store at least one computer program comprising instructions that, when executed by at least one processor, cause the at least one processor to perform operations according to some implementations of the present disclosure. A computer program or computer program product may be recorded on at least one computer-readable (non-transitory) storage medium and may contain instructions that, when executed, cause (at least one processor) to perform operations according to some implementations of the present specification.

[0398] A method performed by the UE, or in the UE, the processing device, the computer-readable (non-transitory) storage medium, and / or the computer program product, the operations may include: receiving a synchronization signal block (SSB) in a first period on a cell (S2501); transmitting an uplink channel for a SSB period change request for the cell (S2503); receiving a response to the uplink channel (S2505); determining a second time point based on a first time point at which the response is received; and receiving the SSB in a second period different from the first period during a time interval starting from the second time point (S2507) on the cell.

[0399] Figure 26 illustrates the flow of downlink (DL) signal transmission in a BS according to some implementations of the present specification.

[0400] A BS may perform operations according to some implementations of the present disclosure in connection with receiving a DL signal. The BS may include at least one transceiver; at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations according to some implementations of the present disclosure. A processing device for the BS may include at least one processor; and at least one computer memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations according to some implementations of the present disclosure. A computer-readable (non-transitory) storage medium may store at least one computer program comprising instructions that, when executed by the at least one processor, cause the at least one processor to perform operations according to some implementations of the present disclosure. A computer program or computer program product may be recorded on at least one computer-readable (non-transitory) storage medium and may contain instructions that, when executed, cause (at least one processor) to perform operations according to some implementations of the present specification.

[0401] A method performed by the BS, or in the BS, the processing device, the computer-readable (non-transitory) storage medium, and / or the computer program product, the operations may include: receiving a synchronization signal block (SSB) in a first period on a cell (S2601); transmitting an uplink channel for a SSB period change request for the cell (S2603); receiving a response to the uplink channel (S2605); determining a second time point based on a first time point at which the response is received; and transmitting the SSB in a second period different from the first period during a time interval starting from the second time point (S2607).

[0402] In some implementations related to FIG. 25 or FIG. 26, the uplink channel may be a random access channel.

[0403] In some implementations related to FIG. 25 or FIG. 26, the response may be a random access response to the random access channel.

[0404] In some implementations related to FIG. 25 or FIG. 26, a point in time after a predetermined offset after the first point in time may be determined to be the second point in time.

[0405] In some implementations related to FIG. 25 or FIG. 26, the operations may include: receiving or transmitting information regarding the predetermined offset.

[0406] In some implementations related to FIG. 25 or FIG. 26, the operations may include: receiving information regarding the duration of the time interval.

[0407] As described above, the examples disclosed in this specification are provided to enable those skilled in the art to implement and practice the disclosure. While the examples have been described above with reference to the examples of this specification, those skilled in the art will appreciate that various modifications and variations may be made to the examples of this specification. Accordingly, this disclosure is not intended to be limited to the examples described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0408] Implementations of this specification can be used in wireless communication systems, BSs, user equipment, and other equipment.

Claims

1. In a method performed by a device, Receive a synchronization signal block (SSB) in the first cycle on the cell; Transmit an uplink channel for a SSB cycle change request for the above cell; Receive a response for the above uplink channel; Determining a second time point based on the first time point at which the above response was received; and During a time interval starting from the second point in time, including receiving the SSB on the cell in a second period different from the first period, method.

2. In paragraph 1, The above uplink channel is a random access channel. method.

3. In paragraph 2, The above response is a random access response to the random access channel. method.

4. In paragraph 1, The point in time after the predetermined offset after the first point in time is determined to be the second point in time, method.

5. In paragraph 4, Including receiving information about the above predetermined offset, method.

6. In paragraph 1, Including receiving information about the duration of the above time interval, method.

7. At least one transmitter / receiver; at least one processor; and At least one computer memory operably connected to said at least one processor and storing instructions that, when executed, cause said at least one processor to perform operations, said operations comprising: Receive a synchronization signal block (SSB) in the first cycle on the cell; Transmit an uplink channel for a SSB cycle change request for the above cell; Receive a response for the above uplink channel; Determining a second time point based on the first time point at which the above response was received; and During a time interval starting from the second point in time, including receiving the SSB on the cell in a second period different from the first period, machinery and tools.

8. At least one processor; and At least one computer memory operably connected to said at least one processor and storing instructions that, when executed, cause said at least one processor to perform operations, said operations comprising: Receive a synchronization signal block (SSB) in the first cycle on the cell; Receive a synchronization signal block (SSB) in the first cycle on the cell; Transmit an uplink channel for a SSB cycle change request for the above cell; Receive a response for the above uplink channel; Determining a second time point based on the first time point at which the above response was received; and During a time interval starting from the second point in time, including receiving the SSB on the cell in a second period different from the first period, Processing unit.

9. In a computer-readable non-transitory storage medium, The storage medium stores at least one program code comprising instructions that, when executed, cause at least one processor to perform operations, the operations comprising: Receive a synchronization signal block (SSB) in the first cycle on the cell; Transmit an uplink channel for a SSB cycle change request for the above cell; Receive a response for the above uplink channel; Determining a second time point based on the first time point at which the above response was received; and During a time interval starting from the second point in time, including receiving the SSB on the cell in a second period different from the first period, Storage media.

10. In a method performed by a base station, Transmitting a synchronization signal block (SSB) in the first cycle on the cell; Receive an uplink channel for a SSB cycle change request for the above cell; Transmit a response to the above uplink channel; Determine the second time point based on the first time point at which the above response was transmitted; and During a time interval starting from the second point in time, transmitting the SSB on the cell in a second period different from the first period, method.

11. In paragraph 10, The above uplink channel is a random access channel. method.

12. In paragraph 11, The above response is a random access response to the random access channel. method.

13. In paragraph 10, The point in time after the predetermined offset after the first point in time is determined to be the second point in time, method.

14. In paragraph 13, Including transmitting information about the above predetermined offset, method.

15. In paragraph 10, Including transmitting information about the duration of the above time interval, method.

16. At least one transmitter / receiver; at least one processor; and At least one computer memory operably connected to said at least one processor and storing instructions that, when executed, cause said at least one processor to perform operations, said operations comprising: Transmitting a synchronization signal block (SSB) in the first cycle on the cell; Receive an uplink channel for a SSB cycle change request for the above cell; Transmit a response to the above uplink channel; Determine the second time point based on the first time point at which the above response was transmitted; and During a time interval starting from the second point in time, transmitting the SSB on the cell in a second period different from the first period, Base station.

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