Method for receiving downlink signal, user equipment, processing device, storage medium, method for transmitting downlink signal, and base station

Abstract

A first type of synchronization signal block (SSB) is transmitted at a first type of SSB time in a first mode on a cell. A second type of SSB is transmitted at a second type of SSB time on the cell based on transitioning from the first mode to the second mode. The first type of SSB includes a PSS, an SSS, and a PCBCH, and the second type of SSB has a different structure than the first type of SSB.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system. Background Art

[0002] Various technologies such as machine-to-machine (M2M) communication, machine-type communication (MTC), and various devices requiring high data throughput (e.g., smart phones and tablet personal computers (PCs)) have emerged and become popular. Therefore, the data throughput required to be processed in cellular networks has increased rapidly. In order to meet this rapidly increasing data throughput, carrier aggregation technology or cognitive radio technology for effectively using more frequency bands and multiple input multiple output (MIMO) technology or multiple base station (BS) cooperation technology for increasing the data capacity transmitted on limited frequency resources have been developed.

[0003] As more and more communication devices require greater communication capacity, enhanced mobile broadband (eMBB) communication is needed relative to traditional radio access technology (RAT). In addition, massive machine type communication (mMTC), which provides various services anytime and anywhere by connecting multiple devices and objects to each other, is a major issue to be considered in next-generation communications.

[0004] Discussions are also underway to design communication systems that take into account services / user equipment (UE) that are sensitive to reliability and latency. Discussions are also underway to introduce next generation RATs that take into account eMBB communications, mMTC, ultra-reliable low latency communications (URLLC), etc.

[0005] As the number of services / user equipments (UEs) that a network needs to support increases rapidly, there is an increasing demand for not only UE power saving but also network power saving. Summary of the invention

[0006] Technical issues

[0007] One object of the present disclosure is to provide a method and process for network energy saving.

[0008] Another object of the present disclosure is to provide a method and process for sending a downlink signal to achieve network energy saving.

[0009] The objects to be achieved by using the present disclosure are not limited to those specifically described above, and other objects not described herein will be more clearly understood by those skilled in the art from the following detailed description.

[0010] Technical Solution

[0011] In one aspect of the present disclosure, a method for receiving a downlink signal by a user equipment (UE) in a wireless communication system is provided herein. The method comprises the following steps: monitoring a first type synchronization signal block (SSB) for a first mode on a cell; acquiring time and frequency synchronization with the cell from the first type SSB based on detecting the first type SSB; monitoring a second type SSB on the cell based on transitioning from the first mode to the second mode; and acquiring time and frequency synchronization with the cell from the second type SSB based on detecting the second type SSB. Among four consecutive orthogonal frequency division multiplexing (OFDM) symbols for the first type SSB, the first type SSB includes a primary synchronization signal (PSS) in the first OFDM symbol, a secondary synchronization signal (SSS) in the third OFDM symbol, and a physical broadcast channel (PBCH) in the second to fourth OFDM symbols, while leaving a portion for the SSS in the third OFDM symbol. The second type SSB has a structure different from the first type SSB.

[0012] In another aspect of the present disclosure, a UE configured to receive a downlink signal in a wireless communication system is provided herein. The UE includes: at least one transceiver; at least one processor; and at least one computer memory, which is operatively connected to the at least one processor and stores instructions, which, when executed, cause the at least one processor to perform operations. The operations include: monitoring a first type of SSB for a first mode on a cell; acquiring time and frequency synchronization with the cell from the first type of SSB based on detecting the first type of SSB; monitoring a second type of SSB on a cell based on a transition from the first mode to the second mode; and acquiring time and frequency synchronization with the cell from the second type of SSB based on detecting the second type of SSB. Among four consecutive OFDM symbols for the first type of SSB, the first type of SSB includes a PSS in the first OFDM symbol, an SSS in the third OFDM symbol, and a PBCH in the second to fourth OFDM symbols, while leaving a portion for the SSS in the third OFDM symbol. The second type of SSB has a different structure from the first type of SSB.

[0013] In another aspect of the present disclosure, a processing device is provided herein. The processing device includes: at least one processor; and at least one computer memory, which is operatively connected to the at least one processor and stores instructions, which, when executed, cause the at least one processor to perform operations. The operations include: monitoring a first type of SSB for a first mode on a cell; based on detecting the first type of SSB, acquiring time and frequency synchronization with the cell from the first type of SSB; based on transitioning from the first mode to the second mode, monitoring a second type of SSB on the cell; and based on detecting the second type of SSB, acquiring time and frequency synchronization with the cell from the second type of SSB. Among the four consecutive OFDM symbols for the first type of SSB, the first type of SSB includes a PSS in the first OFDM symbol, an SSS in the third OFDM symbol, and a PBCH in the second to fourth OFDM symbols, while leaving a portion for the SSS in the third OFDM symbol. The second type of SSB has a different structure from the first type of SSB.

[0014] In another aspect of the present disclosure, a computer-readable storage medium is provided herein, which is configured to store at least one program code including instructions, which when executed cause at least one processor to perform operations. The operations include: monitoring a first type of SSB for a first mode on a cell; based on detecting the first type of SSB, obtaining time and frequency synchronization with the cell from the first type of SSB; based on transitioning from the first mode to the second mode, monitoring a second type of SSB on the cell; and based on detecting the second type of SSB, obtaining time and frequency synchronization with the cell from the second type of SSB. Among the four consecutive OFDM symbols for the first type of SSB, the first type of SSB includes a PSS in the first OFDM symbol, an SSS in the third OFDM symbol, and a PBCH in the second to fourth OFDM symbols, while leaving a portion for the SSS in the third OFDM symbol. The second type of SSB has a different structure from the first type of SSB.

[0015] In another aspect of the present disclosure, a method for transmitting a downlink signal by a base station (BS) to a UE in a wireless communication system is provided herein. The method comprises the following steps: transmitting a first type SSB on a cell; and transmitting a second type SSB on a cell based on a transition from a first mode to a second mode. Among four consecutive OFDM symbols for the first type SSB, the first type SSB includes a PSS in the first OFDM symbol, an SSS in the third OFDM symbol, and a PBCH in the second to fourth OFDM symbols, while leaving a portion for the SSS in the third OFDM symbol. The second type SSB has a different structure from the first type SSB.

[0016] In another aspect of the present disclosure, a BS configured to send a downlink signal to a UE in a wireless communication system is provided herein. The BS includes: at least one transceiver; at least one processor; and at least one computer memory, which is operatively connected to the at least one processor and stores instructions, which, when executed, cause the at least one processor to perform operations. The operations include: sending a first type of SSB on a cell; and sending a second type of SSB on a cell based on a transition from a first mode to a second mode. Among four consecutive OFDM symbols for the first type of SSB, the first type of SSB includes a PSS in the first OFDM symbol, an SSS in the third OFDM symbol, and a PBCH in the second to fourth OFDM symbols, while leaving a portion for the SSS in the third OFDM symbol. The second type of SSB has a different structure from the first type of SSB.

[0017] In various aspects of the present disclosure, among four consecutive OFDM symbols for the second type SSB, the second type SSB may include a PSS in the first OFDM symbol, an SSS in the third OFDM symbol, and a tracking reference signal (TRS) in the second and fourth OFDM symbols.

[0018] In various aspects of the present disclosure, the second type SSB may occupy fewer resource blocks than the resource blocks occupied by the PSS and SSS of the first type SSB.

[0019] In various aspects of the present disclosure, the second type SSB may consist of a cyclic prefix (CP), at least one random access preamble code, and a guard period (GP).

[0020] In various aspects of the present disclosure, the second type SSB may include: i) PSS in the first and second OFDM symbols and SSS in the third and fourth OFDM symbols among four consecutive OFDM symbols for the second type SSB; or ii) PSS in the first and fourth OFDM symbols and SSS in the second and third OFDM symbols among four consecutive OFDM symbols for the second type SSB.

[0021] In various aspects of the present disclosure, the second type SSB may apply a subcarrier spacing for the SSS that is twice the subcarrier spacing for a physical downlink shared channel on the cell.

[0022] In various aspects of the present disclosure, the second mode may be a network energy saving mode.

[0023] The above solutions are only some examples of the present disclosure, and those skilled in the art can deduce and understand various examples into which the technical features of the present disclosure are incorporated from the following detailed description.

[0024] Beneficial Effects

[0025] According to implementations of the present disclosure, energy saving methods and processes for a network, a base station (BS) and / or a user equipment (UE) may be provided.

[0026] According to an implementation of the present disclosure, a method and process for transmitting a downlink signal may be provided to achieve energy saving of a network, a BS and / or a UE.

[0027] Effects according to the present disclosure are not limited to those specifically described above, and other effects not described herein will be more clearly understood by those skilled in the art to which the present disclosure relates from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are included to provide a further understanding of the present disclosure, and illustrate examples of implementations of the present disclosure and together with the detailed description serve to explain the implementations of the present disclosure:

[0029] Figure 1 An example of a communication system 1 to which an implementation of the present disclosure is applied is shown;

[0030] Figure 2 is a block diagram illustrating an example of a communication device capable of executing the method according to the present disclosure;

[0031] Figure 3 Another example of a wireless device capable of performing implementations of the present disclosure is shown;

[0032] Figure 4 An example of a frame structure used in a wireless communication system based on the 3rd Generation Partnership Project (3GPP) is shown;

[0033] Figure 5 a resource grid showing time slots;

[0034] Figure 6 Showing physical channels in a 3rd Generation Partnership Project (3GPP)-based communication system as an exemplary wireless communication system and a signal transmission / reception process using the physical channels;

[0035] Figure 7 A bitmap is shown for indicating the synchronization signal block (SSB) actually transmitted;

[0036] Figure 8 Shows the system information (SI) acquisition process;

[0037] Fig. 9 A random access procedure applicable to an implementation of the present disclosure is shown;

[0038] Fig.10An example of physical downlink shared channel (PDSCH) time domain resource assignment (TDRA) over a physical downlink control channel (PDCCH) and an example of physical uplink shared channel (PUSCH) TDRA over the PDCCH are shown;

[0039] Fig.11 The multiplexing pattern for SSB and control resource set (CORESET) is shown;

[0040] Fig.12 The following diagram shows a scenario where a macro cell and a small cell are carrier aggregated;

[0041] Figures 13 to 15 illustrates the structure of an Energy Saving Discovery Signal (ES-DRS) according to some implementations of the present disclosure;

[0042] Fig.16 shows the structure of the synchronization signal / physical broadcast channel (SS / PBCH) block;

[0043] Fig.17 and Fig.18 An exemplary physical random access channel (PRACH) preamble format is shown;

[0044] Fig.19 A flow chart showing a downlink (DL) signal reception process by a user equipment (UE) according to some implementations of the present disclosure; and

[0045] Fig. 20 A flow of DL signal transmission by a base station (BS) according to some implementations of the present disclosure is shown. DETAILED DESCRIPTION

[0046] Hereinafter, implementations according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description given below with reference to the accompanying drawings is intended to illustrate exemplary implementations of the present disclosure, rather than to show the only implementations that can be implemented according to the present disclosure. The following detailed description includes specific details in order to provide a thorough understanding of the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure can be practiced without these specific details.

[0047] In some cases, known structures and devices may be omitted or may be shown in block diagram form, thereby focusing on important features of the structures and devices so as not to obscure the concepts of the present disclosure. The same reference numerals will be used throughout the present disclosure to refer to the same or similar parts.

[0048] The following techniques, devices and systems can be applied to various wireless multiple access systems. For example, multiple access systems may 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, multi-carrier frequency division multiple access (MC-FDMA) systems, etc. CDMA can be implemented by radio technologies such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented by radio technologies such as Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), Enhanced Data Rate for GSM Evolution (EDGE) (i.e., GERAN), etc. OFDMA can be specifically implemented by radio technologies such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE 802.20, Evolved UTRA (E-UTRA), etc. UTRA is part of Universal Mobile Telecommunications System (UMTS), and 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is part of E-UMTS using E-UTRA. 3GPP LTE adopts OFDMA on downlink (DL) and SC-FDMA on uplink (UL). LTE-advanced (LTE-A) is an evolved version of 3GPP LTE.

[0049] For the convenience of description, the description will be given under the assumption that the present disclosure is applied to LTE and / or new RAT (NR). However, the technical features of the present disclosure are not limited thereto. For example, although the following detailed description is given based on a mobile communication system corresponding to a 3GPP LTE / NR system, the mobile communication system is applicable to any other mobile communication system except for matters specific to the 3GPP LTE / NR system.

[0050] For terms and techniques used in the present disclosure that are not described in detail, reference may be made to standard specifications based on 3GPP (for example, 3GPP TS 36.211, 3GPP TS 36.212, 3GPP TS 36.213, 3GPP TS 36.321, 3GPP TS 36.300, 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.).

[0051] In an example of the present disclosure described later, if a device "assumes" something, this may mean that a channel transmission entity transmits a channel in accordance with the corresponding "assumption". This may also mean that a channel reception entity receives or decodes a channel in a form that conforms to the "assumption" under the premise that the channel is transmitted in accordance with the "assumption".

[0052] In the present disclosure, a user equipment (UE) may be fixed or mobile. Each of the various devices that transmit and / or receive user data and / or control information by communicating with a base station (BS) may be a UE. The term UE may be referred to as a terminal device, a mobile station (MS), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, a personal digital assistant (PDA), a wireless modem, a handheld device, etc. In the present disclosure, a BS refers to a fixed station that communicates with a UE and / or another BS and exchanges data and control information with the UE and another BS. The term BS may be referred to as an advanced base station (ABS), a node B (NB), an evolved node B (eNB), a base transceiver system (BTS), an access point (AP), a processing server (PS), etc. Specifically, a BS of a universal terrestrial radio access (UTRAN) is referred to as an NB, a BS of an evolved UTRAN (E-UTRAN) is referred to as an eNB, and a BS of a new radio access technology network is referred to as a gNB. In the following, for the convenience of description, NB, eNB or gNB will be referred to as a BS regardless of the type or version of the communication technology.

[0053] In the present disclosure, a node refers to a fixed point that can send / receive a radio signal to / from a UE by communicating with the UE. Regardless of its name, various types of BSs can be used as nodes. For example, a BS, NB, eNB, picocell eNB (PeNB), home eNB (HeNB), repeater, transponder, etc. can be a node. In addition, a node may not be a BS. For example, a radio remote head (RRH) or a radio remote unit (RRU) can be a node. Typically, RRH and RRU have a power level lower than that of the BS. Since the RRH or RRU (hereinafter, RRH / RRU) is usually connected to the BS via a dedicated line such as an optical cable, the collaborative communication according to the RRH / RRU and the BS can be smoothly performed compared to the collaborative communication according to the BS connected via a wireless link. At least one antenna is installed per node. The antenna may refer to a physical antenna port or to a virtual antenna or an antenna group. A node may also be referred to as a point.

[0054] In the present disclosure, a cell refers to a specific geographical area where one or more nodes provide communication services. Therefore, in the present disclosure, communication with a specific cell may mean communication with a BS or node that provides communication services to a specific cell. The DL / UL signal of a specific cell refers to the DL / UL signal from / to the BS or node that provides communication services to the specific cell. A cell that provides UL / DL communication services to a UE is particularly referred to as a service cell. In addition, the channel state / quality of a specific cell refers to the channel state / quality of a channel or communication link generated between a BS or node that provides communication services to a specific cell and the UE. In a 3GPP-based communication system, a UE can use a CRS sent on a cell-specific reference signal (CRS) resource and / or a CSI-RS sent on a channel state information reference signal (CSI-RS) resource (allocated to a specific node by an antenna port of a specific node) to measure the DL channel state from a specific node.

[0055] The 3GPP-based communication system uses the concept of a cell in order to manage radio resources, and distinguishes a cell related to radio resources from a cell of a geographical area.

[0056] A "cell" of a geographic area may be understood as a coverage area in which a node can use a carrier to provide services, and a "cell" of radio resources is associated with a bandwidth (BW) which is a frequency range configured by a carrier. Since the DL coverage (the range in which a node can send a valid signal) and the UL coverage (the range in which a node can receive a valid signal from a UE) depend on the carrier that carries the signal, the coverage of a node may also be associated with the coverage of a "cell" of radio resources used by the node. Therefore, the term "cell" may be used to indicate the service coverage of a node at times, to indicate a radio resource at other times, or to indicate a range that a signal using a radio resource can reach with effective strength at other times.

[0057] In the 3GPP communication standard, the concept of a cell is used to manage radio resources. A "cell" associated with a radio resource is defined by a combination of DL resources and UL resources (i.e., a combination of DL component carriers (CCs) and UL CCs). A cell may be configured only by DL resources, or by a combination of DL resources and UL resources. If carrier aggregation is supported, the link between the carrier frequency of a DL resource (or DL ​​CC) and the carrier frequency of a UL resource (or UL CC) may be indicated by system information. For example, the combination of DL resources and UL resources may be indicated by a system information block type 2 (SIB2) link. In this case, the carrier frequency may be equal to or different from the center frequency of each cell or CC. When carrier aggregation (CA) is configured, the UE has only one radio resource control (RRC) connection with the network. During RRC connection establishment / reestablishment / handover, one serving cell provides non-access layer (NAS) mobility information. During RRC connection reestablishment / handover, one serving cell provides security input. The cell is called a primary cell (Pcell). Pcell refers to a cell operating on the primary frequency where the UE performs an initial connection establishment process or initiates a connection reestablishment process. According to the UE capabilities, the secondary cell (Scell) can be configured to form a set of serving cells together with the Pcell. The Scell ​​can be configured after the RRC connection establishment is completed and is used to provide additional radio resources in addition to the resources of the specific cell (SpCell). The carrier corresponding to the Pcell on the DL is called the downlink primary CC (DL PCC), and the carrier corresponding to the Pcell on the UL is called the uplink primary CC (UL PCC). The carrier corresponding to the Scell ​​on the DL is called the downlink secondary CC (DL SCC), and the carrier corresponding to the Scell ​​on the UL is called the uplink secondary CC (UL SCC).

[0058] In dual connectivity (DC) operation, the term special cell (SpCell) refers to a Pcell of a primary cell group (MCG) or a primary secondary cell (Pcell) of a secondary cell group (SCG). SpCell supports PUCCH transmission and contention-based random access and is always enabled. MCG is a group of service cells associated with a master node (e.g., BS) and includes SpCell (Pcell) and optionally one or more Scells. For a UE configured with DC, SCG is a subset of the service cells associated with the secondary node and includes PSCell and 0 or more Scells. PSCell is the primary Scell ​​of the SCG. For a UE in RRC_CONNECTED state that is not configured with CA or DC, there is only one service cell that includes only Pcell. For a UE in RRC_CONNECTED state that is configured with CA or DC, the term service cell refers to a set of cells including SpCell and all Scells. In DC, two medium access control (MAC) entities are configured for the UE, i.e., one MAC entity for MCG and one MAC entity for SCG.

[0059] For a UE configured with CA but not configured with DC, a Pcell PUCCH group (also referred to as a primary PUCCH group) including a Pcell and 0 or more Scells and a Scell ​​PUCCH group (also referred to as a secondary PUCCH group) including only Scells may be configured. For an Scell, a Scell ​​(hereinafter, PUCCH Scell) that transmits a PUCCH associated with a corresponding cell may be configured. The Scell ​​indicating that the PUCCH Scell ​​belongs to the Scell ​​PUCCH group (i.e., the secondary PUCCH group) and performs PUCCH transmission of related uplink control information (UCI) on the PUCCH Scell. If the PUCCH Scell ​​is not indicated for the Scell ​​or the cell indicating that the PUCCH transmission for the Scell ​​is the Pcell, the Scell ​​belongs to the Pcell PUCCH group (i.e., the primary PUCCH group) and performs PUCCH transmission of related UCI on the Pcell. In the following, if the UE is configured with an SCG and some implementations of the present disclosure related to PUCCH are applied to the SCG, the primary cell may refer to the PSCell of the SCG. If the UE is configured with a PUCCH Scell ​​and some implementations of the present disclosure related to PUCCH are applied to a secondary PUCCH group, the primary cell may refer to a PUCCH Scell ​​of the secondary PUCCH group.

[0060] In a wireless communication system, a UE receives information from a BS on DL, and a UE transmits information to a BS on UL. The information transmitted and / or received by the BS and the UE includes data and various control information, and there are various physical channels according to the type / purpose of the information transmitted and / or received by the UE and the BS.

[0061] The communication standards based on 3GPP define DL physical channels corresponding to resource elements carrying information from high layers and DL physical signals corresponding to resource elements used by the physical layer but not carrying information from high layers. For example, physical downlink shared channel (PDSCH), physical broadcast channel (PBCH), physical multicast channel (PMCH), physical control format indicator channel (PCFICH), physical downlink control channel (PDCCH), etc. are defined as DL physical channels, and reference signals (RS) and synchronization signals are defined as DL physical signals. RS (also called pilot) represents a signal with a predefined special waveform known to both BS and UE. For example, demodulation reference signal (DMRS), channel state information RS (CSI-RS), positioning reference signal (PRS), etc. are defined as DL RS. The communication standards based on 3GPP define UL physical channels corresponding to resource elements carrying information from high layers and UL physical signals corresponding to resource elements used by the physical layer but not carrying information from high 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 UL physical channels, and a DMRS for UL control / data signals, a sounding reference signal (SRS) for UL channel measurement, etc. are defined.

[0062] In the present disclosure, PDCCH refers to a set of time-frequency resources (e.g., resource elements (REs)) carrying downlink control information (DCI), and PDSCH refers to a set of time-frequency resources carrying DL data. PUCCH, PUSCH, and PRACH refer to a set of time-frequency resources carrying UCI, a set of time-frequency resources carrying UL data, and a set of time-frequency resources carrying random access signals, respectively. In the following description, "UE sends / receives PUCCH / PUSCH / PRACH" is used as the same meaning as the UE sends / receives UCI / UL data / random access signals on PUCCH / PUSCH / PRACH or through PUSCH / PUCCH / PRACH, respectively. In addition, "BS sends / receives PBCH / PDCCH / PDSCH" is used as the same meaning as the BS sends broadcast information / DCI / DL data on PBCH / PDCCH / PDSCH or through PBCH / PDCCH / PDSCH, respectively.

[0063] In the present specification, radio resources (eg, time-frequency resources) scheduled or configured by a BS for a UE to transmit or receive a PUCCH / PUSCH / PDSCH may be referred to as PUCCH / PUSCH / PDSCH resources.

[0064] Since the communication device receives a synchronization signal (SS), DMRS, CSI-RS, PRS, PBCH, PDCCH, PDSCH, PUSCH and / or PUCCH in the form of a radio signal on a cell, the communication device may not select and receive a radio signal including only a specific physical channel or a specific physical signal through a radio frequency (RF) receiver, or may not select and receive a radio signal without a specific physical channel or a specific physical signal through an RF receiver. In actual operation, the communication device receives a radio signal on a cell via an RF receiver, converts the radio signal as an RF band signal into a baseband signal, and then uses one or more processors to decode the physical signal and / or physical channel in the baseband signal. Therefore, in some implementations of the present disclosure, not receiving a physical signal and / or a physical channel may mean that the communication device does not attempt to recover the physical signal and / or the physical channel from the radio signal, for example, does not attempt to decode the physical signal and / or the physical channel, rather than the non-communication device actually receiving a radio signal including the corresponding physical signal and / or the physical channel.

[0065] As more and more communication devices require greater communication capacity, eMBB communication relative to traditional radio access technology (RAT) is needed. In addition, large-scale MTC, which provides various services anytime and anywhere by connecting multiple devices and objects to each other, is a major issue to be considered in the next generation of communications. In addition, the design of communication systems that take into account services / UEs that are sensitive to reliability and delay is also being discussed. Considering eMBB communication, large-scale MTC, ultra-reliable low-latency communication (URLLC), etc., the introduction of the next generation RAT is being discussed. Currently, in 3GPP, research on the next generation mobile communication system after EPC is underway. In this disclosure, for convenience, the corresponding technology is referred to as a new RAT (NR) or a fifth generation (5G) RAT, and a system using NR or supporting NR is referred to as an NR system.

[0066] Figure 1 An example of a communication system 1 to which an implementation of the present disclosure is applied is shown. Figure 1, the communication system 1 applied to the present disclosure includes a wireless device, a BS, and a network. Here, the wireless device refers to a device that performs communication using a RAT (e.g., 5G NR or LTE (e.g., E-UTRA)), and may be referred to as a communication / radio / 5G device. The wireless device may include (but is not limited to) a robot 100a, a vehicle 100b-1 and 100b-2, an extended reality (XR) device 100c, a handheld device 100d, a home appliance 100e, an Internet of Things (IoT) device 100f, and an artificial intelligence (AI) device / server 400. For example, a vehicle may include a vehicle with a wireless communication function, an autonomous driving vehicle, and a vehicle capable of performing vehicle-to-vehicle communication. Here, a vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). The XR device may include an augmented reality (AR) / virtual reality (VR) / mixed reality (MR) device, 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 smart phone, a computer, a wearable device, a home appliance device, a digital signage, a vehicle, a robot, and the like. Handheld devices may include smart phones, smart boards, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., notebooks). Home appliances may include TVs, refrigerators, and washing machines. IoT devices may include sensors and smart meters. For example, BSs and networks may also be implemented as wireless devices, and a specific wireless device may operate as a BS / network node relative to another wireless device.

[0067] The wireless devices 100a to 100f may be connected to the network 300 via the BS 200. The AI ​​technology may be applied to the wireless devices 100a to 100f, and the wireless devices 100a to 100f may be connected to the AI ​​server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. Although the wireless devices 100a to 100f may communicate with each other via the BS 200 / network 300, the wireless devices 100a to 100f may perform direct communication (e.g., side link communication) with each other without passing through the BS / network. For example, vehicles 100b-1 and 100b-2 may perform direct communication (e.g., vehicle-to-vehicle (V2V) / vehicle-to-everything (V2X) communication). An IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., a sensor) or other wireless devices 100a to 100f.

[0068] Wireless communication / connection 150a and 150b may be established between wireless devices 100a to 100f and BS200, and between wireless devices 100a to 100f. Here, wireless communication / connection such as UL / DL communication 150a and sidelink communication 150b (or device-to-device (D2D) communication) may be established through various RATs (e.g., 5G NR). The wireless device and the BS / wireless device may send / receive radio signals to / from each other through wireless communication / connection 150a and 150b. To this end, various configuration information configuration processes for sending / receiving radio signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation, and resource mapping / demapping), and at least a portion of a resource allocation process may be performed based on various proposals of the present disclosure.

[0069] Figure 2 is a block diagram showing an example of a communication device capable of executing the method according to the present disclosure. Figure 2 , the first wireless device 100 and the second wireless device 200 may transmit and / or receive radio signals through various RATs (e.g., LTE and NR). Here, {the first wireless device 100 and the second wireless device 200} may correspond to Figure 1 {wireless device 100x and BS 200} and / or {wireless device 100x and wireless device 100x}.

[0070] The first wireless device 100 may include one or more processors 102 and one or more memories 104, and further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106, and may be configured to implement the functions, processes and / or methods described / proposed below. For example, the processor 102 may process the information in the memory 104 to generate first information / signal, and then transmit a radio signal including the first information / signal through the transceiver 106. The processor 102 may receive a radio signal including second information / signal through the transceiver 106, and then store information obtained by processing the second information / signal 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 execute part or all of the processes controlled by the processor 102 or store software codes including commands for executing the processes 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 a RAT (e.g., LTE or NR). The transceiver 106 may be connected to the processor 102 and transmit and / or receive radio signals through one or more antennas 108. Each transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with a radio frequency (RF) unit. In the present disclosure, a wireless device may represent a communication modem / circuit / chip.

[0071] The second wireless device 200 may include one or more processors 202 and one or more memories 204, and further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206, and may be configured to implement the functions, processes and / or methods described / proposed below. For example, the processor 202 may process the information in the memory 204 to generate third information / signals, and then transmit a radio signal including the third information / signals through the transceiver 206. The processor 202 may receive a radio signal including fourth information / signals through the transceiver 206, and then store information obtained by processing 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 execute part or all of the processes controlled by the processor 202 or store software codes including commands for executing the processes 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 a RAT (e.g., LTE or NR). The transceiver 206 may be connected to the processor 202 and transmit and / or receive radio signals through one or more antennas 208. Each transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with an RF unit. In the present disclosure, a wireless device may represent a communication modem / circuit / chip.

[0072] The wireless communication technology implemented in the wireless devices 100 and 200 of the present disclosure may include narrowband Internet of Things for low-power communication as well as LTE, NR and 6G. For example, NB-IoT technology may be an example of low-power wide area network (LPWAN) technology and is implemented in standards such as LTE Cat NB1 and / or LTE Cat NB2. However, NB-IoT technology is not limited to the above names. Additionally or alternatively, the wireless communication technology implemented in the wireless devices XXX and YYY of the present disclosure may perform communication based on LTE-M technology. For example, LTE-M technology may be an example of LPWAN technology and is referred to as various names including enhanced machine type communication (eMTC). For example, LTE-M technology may be implemented in accordance with at least one of the following various standards: 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTE non-bandwidth limited (non-BL), 5) LTE-MTC, 6) LTE machine type communication and / or 7) LTE M, etc., but LTE-M technology is not limited to the above names. Additionally or alternatively, in consideration of low power communication, the wireless communication technology implemented in the wireless devices XXX and YYY of the present disclosure may include at least one of ZigBee, Bluetooth, and LPWAN, but the wireless communication technology is not limited to the above names. For example, ZigBee technology may be based on various standards such as IEEE 802.15.4 to create a personal area network (PAN) related to small / low power digital communication, and ZigBee technology may be referred to as various names.

[0073] Hereinafter, the hardware elements of the wireless devices 100 and 200 will be described in more detail. One or more protocol layers may be implemented by (but not limited to) one or more processors 102 and 202. For example, one or more processors 102 and 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 and 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 the present disclosure. One or more processors 102 and 202 may generate messages, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in the present disclosure. One or more processors 102 and 202 may generate a signal (e.g., a baseband signal) including a PDU, an SDU, a message, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in the present disclosure, and provide the generated signal to one or more transceivers 106 and 206. One or more processors 102 and 202 may receive a signal (e.g., a baseband signal) from one or more transceivers 106 and 206 and obtain the PDU, SDU, message, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in the present disclosure.

[0074] One or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. As an 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 and 202. The functions, processes, proposals, and / or methods disclosed in the present disclosure may be implemented using firmware or software, and the firmware or software may be configured to include modules, processes, or functions. Firmware or software configured to perform the functions, processes, proposals, and / or methods disclosed in the present disclosure may be included in one or more processors 102 and 202 or stored in one or more memories 104 and 204 to be driven by one or more processors 102 and 202. The functions, processes, proposals, and / or methods disclosed in the present disclosure may be implemented using firmware or software in the form of code, commands, and / or command sets.

[0075] One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, codes, commands and / or instructions. One or more memories 104 and 204 may be configured by read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EPROM), flash memory, hard disk drive, register, cache memory, computer-readable storage medium and / or a combination thereof. One or more memories 104 and 204 may be located inside and / or outside of one or more processors 102 and 202. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 by various technologies such as wired or wireless connections.

[0076] One or more transceivers 106 and 206 may send the user data, control information and / or radio signal / channel mentioned in the method and / or operation flow chart of the present disclosure to one or more other devices. One or more transceivers 106 and 206 may receive the user data, control information and / or radio signal / channel mentioned in the function, process, proposal, method and / or operation flow chart disclosed in the present disclosure from one or more other devices. For example, one or more transceivers 106 and 206 may be connected to one or more processors 102 and 202 and send and receive radio signals. For example, one or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 may send user data, control information or radio signal to one or more other devices. One or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 may receive user data, control information or radio signal from one or more other devices. One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208. One or more transceivers 106 and 206 may be configured to send and receive user data, control information and / or radio signals / channels mentioned in the functional, process, proposal, method and / or operation flow chart disclosed in the present disclosure through one or more antennas 108 and 208. In the present disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106 and 206 may convert received radio signals / channels, etc. from RF band signals to baseband signals so as to process received user data, control information, radio signals / channels, etc. using one or more processors 102 and 202. One or more transceivers 106 and 206 may convert user data, control information, radio signals / channels, etc. processed using one or more processors 102 and 202 from baseband signals to RF band signals. To this end, one or more of the transceivers 106 and 206 may include (analog) oscillators and / or filters.

[0077] Figure 3 Another example of a wireless device capable of executing implementations of the present disclosure is shown. Figure 3 , the wireless devices 100 and 200 may correspond to Figure 2 The wireless devices 100 and 200 of the present invention may be configured by various elements, components, units / parts and / or modules. For example, each of the wireless devices 100 and 200 may include a communication unit 110, a control unit 120, a memory unit 130 and an additional component 140. The communication unit may include a communication circuit 112 and a transceiver 114. For example, the communication circuit 112 may include Figure 2One or more processors 102 and 202 and / or one or more memories 104 and 204. For example, the transceiver 114 may include Figure 2 The control unit 120 is electrically connected to the communication unit 110, the memory 130, and the additional components 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. The control unit 120 may send information stored in the memory unit 130 to the outside (e.g., other communication devices) via the communication unit 110 through a wireless / wired interface, or store information received from the outside (e.g., other communication devices) via the communication unit 110 in the memory unit 130 through a wireless / wired interface.

[0078] The additional components 140 may be configured differently depending on the type of wireless device. For example, the additional components 140 may include at least one of a power supply unit / battery, an input / output (I / O) unit, a drive unit, and a computing unit. The wireless device may be configured in the form of, but not limited to, a robot ( Figure 1 100a), vehicles ( Figure 1 100b-1 and 100b-2), XR devices ( Figure 1 100c), handheld device ( Figure 1 100d), household appliances ( Figure 1 100e), IoT devices ( Figure 1 100f), digital broadcast UE, holographic device, public safety device, MTC device, medical device, fintech device (or financial device), security device, climate / environmental device, AI server / device ( Figure 1 400), BS( Figure 1 200), network nodes, etc. The wireless device can be used in a mobile or fixed location depending on the usage / service.

[0079] exist Figure 3In the wireless devices 100 and 200, various elements, components, units / parts and / or modules in the wireless devices 100 and 200 may all be connected to each other through a wired interface, or at least a part thereof may be wirelessly connected through the communication unit 110. For example, in each of the wireless devices 100 and 200, the control unit 120 and the communication unit 110 may be wired, and the control unit 120 and the first unit (e.g., 130 and 140) may be wirelessly connected through the communication unit 110. The various elements, components, units / parts and / or modules within the wireless devices 100 and 200 may also include one or more elements. For example, the control unit 120 may be configured by a collection of one or more processors. As an example, the control unit 120 may be configured by a collection of a communication control processor, an application processor, an electronic control unit (ECU), a graphics processing unit and a memory control processor. As another example, the memory 130 may be configured by a random access memory (RAM), a dynamic RAM (DRAM), a read-only memory (ROM)), a flash memory, a temporary memory, a non-temporary memory and / or a combination thereof.

[0080] In the present disclosure, at least one memory (e.g., 104 or 204) may store instructions or programs, and these instructions or programs, when executed, may 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 disclosure.

[0081] In the present disclosure, a computer-readable (non-temporary) storage medium may store at least one instruction or program, and when the at least one instruction or program is executed by at least one processor, the at least one processor may cause the at least one processor to perform operations according to some embodiments or implementations of the present disclosure.

[0082] In the present disclosure, 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, and these instructions or programs, when executed, may 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 disclosure.

[0083] In the present disclosure, a computer program may include program code stored on at least one computer-readable (non-transitory) storage medium, and when executed, it is configured to perform operations according to some implementations of the present disclosure or cause at least one processor to perform operations according to some implementations of the present disclosure. 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.

[0084] The communication device of the present disclosure includes: at least one processor; and at least one computer memory, which is operatively connected to the at least one processor and configured to store instructions, which when executed cause the at least one processor to perform operations according to examples of the present disclosure described later.

[0085] Figure 4 An example of a frame structure used in a 3GPP-based wireless communication system is shown.

[0086] Figure 4 The frame structure is only exemplary, and the number of subframes, the number of time slots, and the number of symbols in the frame may be changed differently. In the NR system, different OFDM parameter sets (e.g., subcarrier spacing (SCS)) may be configured for multiple cells aggregated for one UE. Therefore, the (absolute time) duration of time resources including the same number of symbols (e.g., subframes, time slots, or transmission time intervals (TTIs)) may be configured differently for the aggregated cells. Here, the symbol may include an OFDM symbol (or a cyclic prefix-OFDM (CP-OFDM) symbol) and an SC-FDMA symbol (or a discrete Fourier transform-spread-OFDM (DFT-s-OFDM) symbol). In the present disclosure, symbols, OFDM-based symbols, OFDM symbols, CP-OFDM symbols, and DFT-s-OFDM symbols may be used interchangeably.

[0087] Reference Figure 4 In the NR system, UL transmission and DL transmission are organized into frames. Each frame has T f =(△f max *N f / 100)*T c = 10 ms duration and is divided into two half frames of 5 ms each. The basic time unit of NR is T c =1 / (△f max *N f ), where △f max =480*10 3 Hz and N f =4096. For reference, the basic time unit of LTE is T s =1 / (△f ref *N f,ref ), where △f ref =15*10 3 Hz and N f,ref =2048. c and T f With constant κ = T c / T f =64. Each half frame includes 5 subframes, and the duration of a single subframe is T sfThe subframe is further divided into slots, and the number of slots in a subframe depends on the subcarrier spacing. Each slot includes 14 or 12 OFDM symbols based on the cyclic prefix. In normal CP, each slot includes 14 OFDM symbols, and in extended CP, each slot includes 12 OFDM symbols. The parameter set depends on the exponentially scalable subcarrier spacing △f=2 u *15kHz. The following table shows the number of OFDM symbols per time slot (N slot symb ), the number of time slots per frame (N frame,u slot ) and the number of time slots per subframe (N subframe,u slot ).

[0088] [Table 1]

[0089] u <![CDATA[N slot symb ]]> <![CDATA[N frame,u slot ]]> <![CDATA[N subframe,u slot ]]> 0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160 16 5 14 320 32 6 14 640 64

[0090] The following table shows the subcarrier spacing △f = 2 u *15kHz, number of OFDM symbols per slot, number of slots per frame and number of slots per subframe.

[0091] [Table 2]

[0092] u <![CDATA[N slot symb ]]> <![CDATA[N frame,u slot ]]> <![CDATA[N subframe,u slot ]]> 2 12 40 4

[0093] For subcarrier spacing configuration u, the time slots may be indexed in ascending order within a subframe as follows: n u s ∈{0,...,n subframe ,u slot -1}, and are indexed in ascending order within the frame as follows: n u s,f ∈{0,...,n frame,u slot -1}.

[0094] Figure 5 A resource grid of a time slot is shown. A time slot includes multiple (e.g., 14 or 12) symbols in the time domain. For each parameter set (e.g., subcarrier spacing) and carrier, a common resource block (CRB) N is indicated by higher layer signaling (e.g., RRC signaling). start,u grid Begins to define N size,u grid,x *N RB sc subcarriers and N subframe,u symb OFDM symbol resource grid, where N size,u grid,xis the number of resource blocks (RBs) in the resource grid, and the subscript x is DL for the downlink and UL for the uplink. N RB sc is the number of subcarriers per RB. In 3GPP-based wireless communication systems, N RB sc Typically 12. For a given antenna port p, subcarrier spacing configuration u, and transmission link (DL or UL), there is one resource grid. The carrier bandwidth N for subcarrier spacing configuration u is given to the UE through higher-layer parameters (e.g., RRC parameters) size,u grid . 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 representing the symbol position relative to a reference point in the time domain. In the NR system, an RB is defined by 12 consecutive subcarriers in the frequency domain. In the NR system, RBs are classified into CRBs and physical resource blocks (PRBs). For subcarrier spacing configuration u, CRBs are numbered from 0 upwards in the frequency domain. The center of subcarrier 0 of CRB 0 of subcarrier spacing configuration u is equal to "point A" used as a common reference point for the RB grid. PRBs for subcarrier spacing configuration u are defined within a bandwidth part (BWP) and are numbered from 0 to N. size,u BWP,i -1 numbering, where i is the number of BWPs. PRB n in BWPi PRB With CRB u CRB The relationship between n u PRB =n u CRB +N size,u BWP,i Given, where N size BWP,i is the CRB at which the BWP starts relative to CRB 0. A BWP includes multiple consecutive RBs in the frequency domain. For example, a BWP may be a CRB with a given parameter set u in BWP i on a given carrier. i A subset of contiguous CRBs defined by the UE. A carrier may include up to N (e.g., 5) BWPs. A UE may be configured with one or more BWPs on a given component carrier. Data communication is performed through enabled BWPs, and only a predetermined number of BWPs (e.g., one BWP) among the BWPs configured for the UE may be active on the component carrier.

[0095] For each serving cell in the set of DL BWPs or UL BWPs, the network may configure at least an initial DL BWP and one (if the serving cell is configured with uplink) or two (if supplementary uplink is used) initial UL BWPs. The network may configure additional UL and DL BWPs. For each DL BWP or UL BWP, the following parameters may be provided to the UE for the serving cell: i) SCS; ii) CP; iii) start BWP＝ 275 indicates the offset RB set and length L RB CRB N provided as the RRC parameter locationAndBandwidth of the Resource Indicator Value (RIV) start BWP =O carrier +RB start and the number of adjacent RBs N size BWP =L RB , and the value O provided by the RRC parameter offsetToCarrier for SCS carrier ; an index into a set of DL BWP or UL BWP; a set of BWP common parameters; and a set of BWP dedicated parameters.

[0096] Switching between configured BWPs may occur using RRC signaling, DCI and / or inactivity timers or during initiation of random access. If an inactivity timer is configured for the serving cell, expiration of the inactivity timer associated with the serving cell causes the active BWP to switch to the default BWP configured by the network.

[0097] Virtual Resource Blocks (VRBs) can be defined within a BWP and are numbered from 0 to N. size,u BWP,i -1 index, where i represents the BWP number. VRBs may be mapped to PRBs according to an interleaved mapping or a non-interleaved mapping. In some implementations, for non-interleaved VRB to PRB mapping, VRB n may be mapped to PRB n.

[0098] NR frequency bands are defined as two types of frequency ranges, namely, FR1 and FR2. FR2 is also known as millimeter wave (mmW). The following table shows the frequency ranges in which NR can operate.

[0099] [Table 3]

[0100] Frequency range specification Corresponding frequency range Subcarrier spacing FR1 410MHz-7125MHz 15, 30, 60kHz FR2 24250MHz-52600MHz 60, 120, 240kHz

[0101] Figure 6is a diagram showing physical channels in a 3GPP-based communication system as an exemplary wireless communication system and a signal transmission / reception process using the physical channels.

[0102] When the UE is powered on or when the UE has been disconnected from the wireless communication system, the UE searches for a cell to reside in and performs an initial cell search, involving synchronization with a BS in the cell (S11). For the initial cell search, 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 establishes synchronization with the BS based on the PSS / SSS and obtains information such as a cell identification (ID). The UE can obtain broadcast information in the cell based on the PBCH. The UE can receive a DL reference signal (RS) during the initial cell search to monitor the DL channel status.

[0103] After the initial cell search, the UE may camp on the cell. Subsequently, the UE may monitor the PDCCH in the cell and acquire more specific system information by receiving the PDSCH based on the DCI carried on the PDCCH (S12).

[0104] Subsequently, in order to complete the connection with the BS, the UE may perform a random access procedure (S13 to S16). In the random access procedure, for example, the UE may send a preamble on the PRACH (S13) and receive a PDCCH and a random access response (RAR) to the preamble on the PDSCH corresponding to the PDCCH (S14). When the UE fails to receive the RAR directed to the UE, the UE may attempt to retransmit the preamble. In the case of contention-based random access, the UE may send a PUSCH based on the UL resource assignment included in the RAR (S15), and perform a contention resolution procedure including reception of the PDCCH and the PDSCH corresponding to the PDCCH (S16).

[0105] After the above process, the UE may receive PDCCH / PDSCH from the BS (S17) and send PUSCH / PUCCH to the BS (S18) during general UL / DL signal transmission. The control information sent by the UE to the BS is generally referred to as uplink control information (UCI). UCI includes hybrid automatic repeat request acknowledgment / negative acknowledgment (HARQ ACK / NACK), scheduling request (SR) and channel state information (CSI). CSI includes channel quality indicator (CQI), precoding matrix indicator (PMI) and / or rank indication (RI). Typically, UCI is sent on PUCCH. However, when control information and data should be sent simultaneously, control information may be sent on PUSCH. In addition, upon receiving a request / command from the network, the UE may send UCI on PUSCH aperiodically.

[0106] During initial cell selection, the UE assumes that the half-frame including the SSB is repeated with a periodicity of 20ms. Based on the MIB, the UE may check whether there is a control resource set (CORESET) (e.g., CORESET#0) for Type0-PDCCH common search space (CSS), such as CORESET#0. If k SSB <=23 (for FR1) or k SSB <=11 (for FR2), the UE may determine that there is a CORESET for Type0-PDCCH CSS. SSB >23 (for FR1) or k SSB >11 (for FR2), the UE may determine that there is no CORESET for Type0-PDCCH CSS. Type0-PDCCH CSS is a PDCCH search space for sending a PDCCH that schedules a system information (SI) message. If Type0-PDCCH CSS exists, the UE may determine (i) a plurality of consecutive RBs and one or more consecutive symbols included in a CORESET (e.g., CORESET#0) and (ii) a PDCCH opportunity (i.e., a time domain position for receiving a PDCCH) (e.g., search space #0) based on information in the MIB (e.g., pdcch-ConfigSIB1). If Type0-PDCCH CSS does not exist, pdcch-ConfigSIB1 provides information about the frequency position where SSB / SIB1 exists and the frequency range where SSB / SIB1 does not exist.

[0107] Beam sweeping means that the transmission and reception point (TRP) (e.g., BS / cell) changes the beam (direction) of the radio signal over time. In the present disclosure, the terms "beam" and "beam direction" are used interchangeably. SSBs can be sent periodically by beam sweeping. In this case, the SSB index is implicitly linked to the SSB beam. The SSB beam can be changed based on the SSB (index) or based on the SSB (index) group. In the latter case, the SSB beam remains the same within the SSB (index) group. That is, the transmission beam direction of the SSB can be repeated across multiple consecutive SSBs. The SSB set is sent within a 5ms half frame. The set of SSBs sent within a 5ms half frame is called an SSB burst set. Depending on the frequency band to which the carrier belongs, the maximum number of SSBs sent in the SSB burst set is L. max Has values ​​4, 8, or 64. For example, the maximum number of SSBs in an SSB burst set, L max It can be given as follows.

[0108] - For the frequency range up to 3 GHz, L max =4

[0109] -For the frequency range from 3 GHz to 6 GHz, L max =8

[0110] -For the frequency range from 6 GHz to 52.6 GHz, L max =64

[0111] The number of SSBs actually sent can be configured, which can be less than the maximum number L max .

[0112] When multi-beam transmission is not applied, the number of SSB beams is 1.

[0113] Figure 7 A bitmap indicating the SSB actually transmitted is shown.

[0114] Up to L SSBs may be sent within an SSB burst set, and the number / position of SSBs actually sent may vary depending on the BS / cell. The number / position of SSBs actually sent is used for rate matching and measurement, and information about the SSBs actually sent (e.g., ssb-PositionsInBurst) may be indicated as follows.

[0115] - In case of rate matching: Information about the SSB actually transmitted may be indicated by UE-specific RRC signaling or remaining minimum system information (RMSI). UE-specific RRC signaling includes full (e.g., length L) bitmaps for two frequency ranges below 6 GHz and above 6 GHz. On the other hand, as shown, RMSI (i.e., SIB1) includes a full bitmap for the frequency range below 6 GHz and a compressed bitmap for the frequency range above 6 GHz. Specifically, a group bitmap (8 bits) and an intra-group bitmap (8 bits) may be used to indicate information about the SSB actually transmitted. In this case, the resources (e.g., REs) indicated by UE-specific RRC signaling or RMSI may be reserved for SSB transmission, and PDSCH / PUSCH, etc. may consider the SSB resources for rate matching.

[0116] - In case of measurement related: In RRC_CONNECTED mode, the network (e.g., BS) may indicate the set of SSBs to be measured in the measurement period. The SSB set may be indicated for each frequency layer. If there is no indication about the SSB set, the default SSB set is used. The default SSB set includes all SSBs in the measurement period. The full (e.g., length L) bitmap of RRC signaling may be used to indicate the SSB set. In RRC_IDLE mode, the default SSB set is used.

[0117] Figure 8The system information (SI) acquisition process is shown. The UE can acquire access stratum / non-access stratum (AS / NAS) information from the SI acquisition process. The SI acquisition process can be applied to UEs in the following states: RRC_IDLE, RRC_INACTIVE, and RRC_CONNECTED. RRC_CONNECTED refers to a state in which the UE has established an RRC connection with the network. RRC_IDLE refers to a state in which the UE is not registered in a specific cell and has not received an AS context and other information from the network. RRC_INACTIVE refers to a state in which the UE remains in a state called CM-CONNECTED, in which the UE has a signaling connection with the core network for connection management (CM) and is able to move within an area defined by a radio access network (RAN) (e.g., BS) without notifying the RAN. CM_CONNECTED refers to a state in which the UE has a NAS signaling connection with the core network. CM_IDLE refers to a state in which the UE has no NAS signaling connection.

[0118] In a 3GPP-based system, system information (SI) may be classified into a master information block (MIB) and multiple system information blocks (SIBs). The MIB and multiple SIBs are divided into minimum system information (SI) and other SI, where the minimum SI consists of the MIB and system information block 1 (SIB1), and includes basic information required for initial access and information for acquiring any other SI. SIB1 may be referred to as remaining minimum system information (RMSI). Details are provided below.

[0119] -MIB is always sent on BCH with a periodicity of 80ms and is repeated within 80ms. MIB includes information / parameters related to SIB1 reception and is sent through PBCH in SSB. During initial cell selection, the UE assumes that the half frame including the SSB is repeated with a periodicity of 20ms. The UE can determine whether there is a control resource set (CORESET) for the Type0-PDCCH common search space based on the MIB. The Type0-PDCCH common search space is a PDCCH search space and is used to send a PDCCH that schedules SI messages. When a Type0-PDCCH common search space exists, the UE can determine (i) multiple consecutive RBs and one or more consecutive symbols included in the CORESET and (ii) the PDCCH timing (i.e., the time domain position for PDCCH reception) based on the information in the MIB (e.g., pdcch-ConfigSIB1). When there is no Type0-PDCCH common search space, pdcch-ConfigSIB1 provides information about the frequency position where SSB / SIB1 exists and information about the frequency range where SSB / SIB1 does not exist.

[0120] -SIB1 is sent on the downlink shared channel (DL-SCH) with a periodicity of 160ms and a variable transmission repetition periodicity within 160ms. The default transmission repetition periodicity of SIB1 is 20ms, but the actual transmission repetition periodicity depends on the network implementation. SIB1 includes information about the availability and scheduling (e.g., transmission periodicity and SI window size) of the remaining SIBs (hereinafter referred to as 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 at the request of the UE. When SIBx is provided on demand, SIB1 may include the information required by the UE to perform an SI request. SIB1 is a cell-specific SIB. The PDCCH that schedules SIB1 is sent in the Type0-PDCCH common search space, and SIB1 is sent via the PDSCH indicated by the PDCCH.

[0121] -SIBx is included in the SI message and transmitted through the PDSCH. Each SI message is transmitted within a time window (ie, SI window) that occurs periodically.

[0122] Fig. 9 The random access process applicable to the implementation of the present disclosure is shown. Specifically, Fig. 9 (a) shows a 4-step random access process, Fig. 9 (b) shows a 2-step random access process.

[0123] The random access procedure can be used for various purposes, including initial access, UL synchronization adjustment, resource allocation, switching, radio link reconfiguration after radio link failure, and positioning. 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 generally involves initial access, while the dedicated random access procedure is used for UL synchronization reconfiguration in the case of switching, DL data arriving at the network, and positioning. In the contention-based random access procedure, the UE randomly selects a random access (RA) preamble. Therefore, multiple UEs may send the same RA preamble at the same time, so a subsequent contention resolution procedure is required. In the dedicated random access procedure, the UE uses the RA preamble uniquely allocated by the BS to the UE. Therefore, the UE can perform a random access procedure without conflicting with other UEs.

[0124] Reference Fig. 9 (a) of the present invention, the contention-based random access procedure includes the following four steps. The messages sent in steps 1 to 4 may be referred to as message 1 (Msg1) to message 4 (Msg4), respectively.

[0125] - Step 1: UE sends RA preamble on PRACH.

[0126] - Step 2: The UE receives the RAR from the BS on the PDSCH.

[0127] -Step 3: The UE sends UL data to the BS on the PUSCH. The UL data includes a layer 2 (L2) / layer 3 (L3) message.

[0128] - Step 4: The UE receives a contention resolution message from the BS on the PDSCH.

[0129] The UE may receive random access information from the BS in the system information. For example, information about the RACH timing associated with the SSB on the cell may be provided in the system information. The UE may select an SSB whose reference signal received power (RSRP) measured based on the SSB exceeds a threshold among the SSBs received on the cell. The UE may then send an RA preamble on the PRACH associated with the selected SSB. For example, when the UE requires random access, the UE sends Msg1 (e.g., a preamble) to the BS on the PRACH. The BS may identify each RA preamble by the time / frequency resource (RA timing (RO)) carrying the RA preamble and the preamble index (PI). Upon receiving the RA preamble from the UE, the BS sends a RAR message to the UE on the PDSCH. In order to receive the RAR message, the UE monitors the L1 / L2 control channel (PDCCH) with a cyclic redundancy check (CRC) masked with a random access-RNTI (RA-RNTI) within a preconfigured time window (e.g., ra-ResponseWindow), including scheduling information for the RAR message. When scheduling information is received on the PDCCH masked with RA-RNTI, the UE may receive a RAR message on the PDSCH indicated by the scheduling information. The UE then checks whether there is a RAR pointing to the UE in the RAR message. Whether there is a RAR pointing to the UE can be determined by checking whether there is a random access preamble ID (RAPID) of the preamble sent by the UE. The index of the preamble sent by the UE may be the same as the RAPID. The RAR includes the index of the corresponding RA preamble, the timing offset information of UL synchronization (e.g., timing advance command (TAC)), the UL scheduling information (e.g., UL grant) transmitted by Msg3, and the UE temporary identification information (e.g., temporary-C-RNTI (TC-RNTI)). Upon receiving the RAR, the UE sends Msg3 on the PUSCH according to the UL scheduling information and timing offset value in the RAR. Msg3 may include the ID (or global ID) of the UE. In addition, Msg3 may include RRC connection request related information (e.g., RRCSetupRequest message) for initial access to the network. After receiving Msg3, the BS sends a contention resolution message (i.e., Msg4) to the UE. When the UE receives the contention resolution message and the contention resolution is successful, the TC-RNTI is changed to the C-RNTI. Msg4 may include the ID of the UE / RRC connection related information (e.g., RRCSetup message). When the information sent in Msg3 does not match the information received in Msg4 or when the UE does not receive Msg4 within a predetermined time, the UE may determine that the contention resolution has failed and retransmit Msg3.

[0130] The dedicated random access procedure includes the following three steps. The messages sent in step 0 to step 2 may be referred to as Msg0 to Msg2, respectively. The BS may trigger the dedicated random access procedure through a PDCCH serving the purpose of commanding RA preamble transmission (hereinafter, referred to as a PDCCH command).

[0131] - Step 0: The BS allocates a RA preamble to the UE through dedicated signaling.

[0132] - Step 1: UE sends RA preamble on PRACH.

[0133] - Step 2: The UE receives the RAR from the BS on the PDSCH.

[0134] Step 1 and step 2 of the dedicated random access procedure may be the same as step 1 and step 2 of the contention-based random access procedure.

[0135] NR systems may require lower latency than legacy systems. In particular, for delay-sensitive services such as URLLC, a 4-step random access procedure may not be preferred. Various scenarios in NR systems may require a low-latency random access procedure. When the implementation of the present disclosure is implemented together with a random access procedure, the implementation of the present disclosure may be implemented together with the following 2-step random access procedure to reduce the delay involved in the random access procedure.

[0136] Reference Fig. 9 (b), the 2-step random access procedure may be performed in two steps: MsgA transmission from the UE to the BS and MsgB transmission from the BS to the UE. MsgA transmission may include transmission of an RA preamble on the PRACH and transmission of an UL payload on the PUSCH. In MsgA transmission, the PRACH and the PUSCH may be transmitted in time division multiplexing (TDM). Alternatively, in MsgA transmission, the PRACH and the PUSCH may be transmitted in frequency division multiplexing (FDM).

[0137] Upon receiving MsgA, the BS may send MsgB to the UE. MsgB may include the RAR for the UE.

[0138] An RRC connection request related message (e.g., an RRCSetupRequest message) requesting establishment of a connection between the RRC layer of the BS and the RRC layer of the UE may be included in the payload of MsgA. In this case, MsgB may be used to send RRC connection related information (e.g., an RRCSetup message). In contrast, an RRC connection request related message (e.g., an RRCSetupRequest message) may be sent on the PUSCH based on the UL grant in MsgB. In this case, RRC connection related information (e.g., an RRCSetup message) related to the RRC connection request may be sent on the PDSCH associated with the PUSCH transmission after the PUSCH transmission based on MsgB.

[0139] Hereinafter, physical channels available in a 3GPP-based wireless communication system will be described in detail.

[0140] PDCCH carries DCI. For example, PDCCH (i.e., DCI) carries information about the transmission format and resource allocation of the downlink shared channel (DL-SCH), information about the resource allocation of the uplink shared channel (UL-SCH), paging information about the paging channel (PCH), system information about DL-SCH, resource allocation information of control messages of a layer higher than the physical layer (hereinafter, high layer) in the protocol stack of UE / BS (e.g., random access response (RAR) sent on PDSCH), transmission power control commands, information about the activation / deactivation of configuration scheduling (CS), etc. DCI including resource allocation information about DL-SCH is called PDSCH scheduling DCI, and DCI including resource allocation information about UL-SCH is called PUSCH scheduling DCI. DCI includes a cyclic redundancy check (CRC). The CRC is masked / scrambled with various identifiers (e.g., radio network temporary identifier (RNTI)) according to the owner and purpose of the PDCCH. For example, if the PDCCH is for a specific UE, the CRS is masked with a UE identifier (e.g., cell-RNTI (C-RNTI)). If the PDCCH is for a paging message, the CRC is masked with a paging RNTI (P-RNTI). If the PDCCH is for system information (e.g., system information block (SIB)), the CRC is masked with a system information RNTI (SI-RNTI). If the PDCCH is for a random access response, the CRC is masked with a random access-RNTI (RA-RNTI).

[0141] When the PDCCH on one serving cell schedules the PDSCH or PUSCH on another serving cell, it is called cross-carrier scheduling. Cross-carrier scheduling with a carrier indicator field (CIF) allows the PDCCH on the serving cell to schedule resources on another serving cell. When the PDSCH on the serving cell schedules the PDSCH or PUSCH on the serving cell, it is called self-carrier scheduling. When cross-carrier scheduling is used in a cell, the BS may provide information about the cell of the scheduling cell to the UE. For example, the BS may inform the UE whether the serving cell is scheduled by the PDCCH on another (scheduling) cell or by the serving cell. If the serving cell is scheduled by another (scheduling) cell, the BS may inform the UE which cell signals the DL assignment and UL grant of the serving cell. In the present disclosure, the cell carrying the PDCCH is referred to as the scheduling cell, and the cell whose transmission of the PUSCH or PDSCH is scheduled by the DCI included in the PDCCH (i.e., the cell carrying the PUSCH or PDSCH scheduled by the PDCCH) is referred to as the scheduled cell.

[0142] PDSCH is a physical layer UL channel for UL data transmission. PDSCH carries DL data (e.g., DL-SCH transport block) and is subjected to modulation such as quadrature phase shift keying (QPSK), 16 quadrature amplitude modulation (QAM), 64QAM, 256QAM, etc. Codewords are generated by encoding transport blocks (TBs). PDSCH can carry up to two codewords. Scrambling and modulation mapping of each codeword can be performed, and modulation symbols generated from each codeword can be mapped to one or more layers. Each layer is mapped to a radio resource together with a DMRS and generated as an OFDM symbol signal. Then, the OFDM symbol signal is sent through the corresponding antenna port.

[0143] For UL-SCH data transmission, the UE needs to have UL resources available for the UE, and for DL-SCH data reception, the UE needs to have DL resources available for the UE. The BS assigns UL and DL resources to the UE through resource allocation. Resource allocation may include time domain resource allocation (TDRA) and frequency domain resource allocation (FDRA). In the present disclosure, UL resource allocation is also referred to as UL grant, and DL resource allocation is also referred to as DL assignment. The UL grant may be dynamically received by the UE on the PDCCH or in the RAR, or the UL grant may be semi-persistently configured to the UE from the BS through RRC signaling. The DL assignment may be dynamically received by the UE on the PDCCH, or semi-persistently configured to the UE from the BS through RRC signaling.

[0144] On the UL, the BS can dynamically allocate UL resources to the UE via a PDCCH addressed to a temporary identifier (cell radio network temporary identifier, C-RNTI). The UE monitors the PDCCH to detect possible UL grants for UL transmission. The BS can use the configuration grant to allocate UL resources to the UE. Two types of configuration grants can be used, type 1 and type 2. In the case of type 1, the BS directly provides the configured UL grant (including periodicity) via RRC signaling. In the case of type 2, the BS configures the periodicity of the RRC-configured UL grant via RRC signaling, and can signal and enable or disable the configured UL grant by addressing the PDCCH to the configuration scheduling RNTI (CS-RNTI). For example, in the case of type 2, the PDCCH addressed to the CS-RNTI indicates that until deactivation, the corresponding UL grant can be implicitly reused according to the periodicity configured via RRC signaling.

[0145] On the DL, the BS may dynamically allocate DL resources to the UE via a PDCCH addressed to the C-RNTI. The UE monitors the PDCCH to detect possible DL assignments. The BS may allocate DL resources to the UE using semi-persistent scheduling (SPS). The BS may configure the periodicity of the configured DL assignments via RRC signaling, and signal and enable or disable the configured DL assignments via a PDCCH addressed to the CS-RNTI. For example, the PDCCH addressed to the CS-RNTI indicates that until deactivation, the corresponding DL assignment may be implicitly reused according to the periodicity configured via RRC signaling.

[0146] Fig.10 An example of PDSCH TDRA caused by PDCCH and an example of PUSCH TDRA caused by PDCCH are shown.

[0147] The DCI carried by the PDCCH for scheduling PDSCH or PUSCH includes a TDRA field. The TDRA field provides a value m of row index m+1 for the allocation table of PDSCH or PUSCH. The predefined default PDSCH time domain allocation is applied as the allocation table of PDSCH, or the PDSCH TDRA table configured by the BS through the RRC signal pdsch-TimeDomainAllocationList is applied as the allocation table of PDSCH. The predefined default PUSCH time domain allocation is applied as the allocation table of PUSCH, or the PUSCH TDRA table configured by the BS through the RRC signal pusch-TimeDomainAllocationList is applied as the allocation table of PUSCH. The PDSCH TDRA table to be applied and / or the PUSCH TDRA table to be applied can be determined according to fixed / predefined rules (for example, refer to 3GPPTS 38.214).

[0148] In the PDSCH time domain resource configuration, each index row defines the DL assignment with the PDSCH slot offset K0, the start and length indicator SLIV (or the starting position (e.g., starting symbol index S) and allocation length (e.g., number of symbols L) of the PDSCH in the direct slot), and the PDSCH mapping type. In the PUSCH time domain resource configuration, each index row defines the UL grant with the PUSCH slot offset K2, the starting position (e.g., starting symbol index S) and allocation length (e.g., number of symbols L) of the PUSCH in the slot, and the PUSCH mapping type. K0 of PDSCH and K2 of PUSCH indicate the difference between the slot with PDCCH and the slot with PDSCH or PUSCH corresponding to the PDCCH. SLIV represents a joint indicator of the starting symbol S relative to the beginning of the slot with PDSCH or PUSCH and the number of consecutive symbols L counted from symbol S. There are two PDSCH / PUSCH mapping types: one is mapping type A and the other is mapping type B. In the case of PDSCH / PUSCH mapping type A, DMRS is mapped to the PDSCH / PUSCH resource relative to the beginning of the time slot. Depending on other DMRS parameters, one or two symbols of the PDSCH / PUSCH resource may be used as DMRS symbols. For example, in the case of PDSCH / PUSCH mapping type A, according to RRC signaling, the DMRS is located in the third symbol (symbol #2) or the fourth symbol (symbol #3) in the time slot. In the case of PDSCH / PUSCH mapping type B, DMRS is mapped relative to the first OFDM symbol of the PDSCH / PUSCH resource. Depending on other DMRS parameters, one or two symbols from the first symbol of the PDSCH / PUSCH resource may be used as DMRS symbols. For example, in the case of PDSCH / PUSCH mapping type B, DMRS is located at the first symbol allocated for PDSCH / PUSCH. In the present disclosure, the PDSCH / PUSCH mapping type may be referred to as a mapping type or a DMRS mapping type. For example, in the present 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.

[0149] The scheduling DCI includes an FDRA field that provides assignment information about RBs for PDSCH or PUSCH. For example, the FDRA field provides information about a cell used for PDSCH or PUSCH transmission to a UE, information about a BWP used for PDSCH or PUSCH transmission, and / or information about RBs used for PDSCH or PUSCH transmission.

[0150] A CORESET may be defined and / or configured as a set of time-frequency resources in which a UE can monitor a PDCCH. A CORESET has a duration of one to three OFDM symbols and includes a set of PRBs. The PRBs included in the CORESET and the CORESET duration may be provided to the UE via high-level (e.g., RRC) signaling. The UE may monitor the PDCCH candidate set in the configured CORESET according to the corresponding search space set. In the present disclosure, monitoring means decoding (blind decoding) of each PDCCH candidate based on the monitored DCI format. The MIB on the PBCH provides the UE with parameters (e.g., CORESET#0 configuration) for monitoring the PDCCH that schedules the PDSCH carrying SIB1. The PBCH may indicate that there is no associated SIB1. In this case, the UE may be provided not only with a frequency range in which the UE is allowed to assume that there is no SSB associated with SSB1, but also with another frequency range in which the UE is allowed to discover the SSB associated with SIB1. As a CORESET for scheduling at least SIB1, CORESET#0 may be configured via MIB or dedicated RRC signaling.

[0151] One or more CORESETs may be configured for a UE, and multiple CORESETs may overlap in the time / frequency domain. To configure a CORESET, the following parameters may be provided by the BS.

[0152] -controlResourceSetId: indicates information about the identification (ID) of CORESET.

[0153] -frequencyDomainResources: represents the frequency domain resources of the CORESET and is indicated by a bitmap, where each bit corresponds to an RB group (= 6 consecutive RBs). For example, the MSB (most significant bit) of the bitmap corresponds to the first RB group within the BWP. The RB group corresponding to the bit with a value of 1 is allocated as the frequency domain resource of the CORESET.

[0154] -duration: represents the time domain resource of CORESET, specifically, indicates the number of consecutive OFDMA symbols included in CORESET. For example, duration may have a value in the range of 1 to 3.

[0155] -cce-REG-MappingType: indicates the CCE to REG mapping type. Both interleaved and non-interleaved types are supported.

[0156] -precoderGranularity: Indicates the precoder granularity in the frequency domain.

[0157] -tci-StatesPDCCH: Information about the Transmission Configuration Indication (TCI) state of PDCCH (e.g., TCI-StateID)

[0158] -tci-PresentInDCI: indicates whether the TCI field is included in the DCI.

[0159] -pdcch-DMRS-ScramblingID: indicates information used for initialization of the PDCCH DMRS scrambling sequence.

[0160] The PDCCH candidate set monitored by the UE is defined according to the PDCCH search space set. The search space set can 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.

[0161] The UE monitors a set of PDCCH candidates in one or more CORESETs on an active DLBWP on each enabled serving cell configured with PDCCH monitoring according to a corresponding search space set, where monitoring means receiving each PDCCH candidate and decoding according to the monitored DCI format.

[0162] The following table shows the PDCCH search space.

[0163] [Table 4]

[0164]

[0165] The SS set may be configured via system information (e.g., MIB) or UE-specific high-layer (e.g., RRC) signaling. S (e.g., 10) SS sets or fewer SS sets may be configured in each DL BWP of a serving cell. For example, the following parameters / information may be provided for each SS set. Each SS set may be associated with one CORESET, and each CORESET configuration may be associated with one or more SS sets.

[0166] -searchSpaceId: indicates the ID of the SS set.

[0167] -controlResourceSetId: Indicates the CORESET associated with the SS set.

[0168] - monitoringSlotPeriodicityAndOffset: indicates the PDCCH monitoring periodicity (in time slots) and the PDCCH monitoring offset (in time slots).

[0169] -monitoringSymbolsWithinSlot: Indicates the first OFDMA symbol for PDCCH monitoring in the slot where PDCCH monitoring is configured. The first OFDMA symbol is indicated by a bitmap, and each bit corresponds to a corresponding one of the OFDMA symbols in the slot. The MSB of the bitmap corresponds to the first OFDM symbol in the slot. The OFDMA symbol corresponding to the bit with a value of 1 corresponds to the first symbol in the CORESET in the slot.

[0170] -nrofCandidates: indicates the number (eg, one of 0, 1, 2, 3, 4, 5, 6, and 8) of PDCCH candidates for each AL (where AL={1, 2, 4, 8, 16}).

[0171] -searchSpaceType: Indicates whether the SS type is CSS or USS.

[0172] -DCI format: indicates the DCI format of the PDCCH candidate.

[0173] The UE may monitor PDCCH candidates in one or more SS sets in a time slot according to the configuration of the CORESET / SS set. The timing (e.g., time / frequency resource) of monitoring PDCCH candidates is defined as a PDCCH (monitoring) opportunity. One or more PDCCH (monitoring) opportunities may be configured in a time slot.

[0174] Fig.11 The SSB and CORESET multiplexing patterns are shown. Specifically, Fig.11 (a) shows SSB and CORESET multiplexing pattern 1, Fig.11 (b) shows SSB and CORESET multiplexing pattern 2, Fig.11 (c) shows SSB and CORESET multiplexing pattern 3. The SSB and CORESET multiplexing patterns may be defined according to a frequency range (FR) to which a corresponding cell belongs or a subcarrier spacing of an SSB or a PDCCH.

[0175] like Fig.11 As shown, SSB and CORESET can be multiplexed in the time domain, in the time domain and frequency domain, or in the frequency domain.

[0176] The PDCCH candidate set monitored by the UE is defined according to the PDCCH search space set. The search space set can 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.

[0177] The UE monitors a set of PDCCH candidates in one or more CORESETs on an active DLBWP on each enabled serving cell configured with PDCCH monitoring according to a corresponding search space set, where monitoring means receiving each PDCCH candidate and decoding according to the monitored DCI format.

[0178] According to the current 5G specification, SIB1 is sent on the DL-SCH with a periodicity of 160ms or a variable transmission repetition periodicity within 160ms as part of the minimum system information required for cell access. The default transmission repetition periodicity of SIB1 is 20ms, but the actual transmission repetition periodicity depends on the network implementation. For SSB and CORESET multiplexing pattern 1, the transmission repetition period of SIB1 is 20ms. For SSB and CORESET multiplexing pattern 2 / 3, the transmission repetition period of SIB1 is the same as the SSB period. The PDCCH monitoring timing at which the UE attempts to decode the SIB1 PDCCH can be determined based on information in the MIB (e.g., pdcch-ConfigSIB1). For example, during cell search, if the UE determines that there is a Type0-PDCCH CSS set based on the MIB, the UE can determine the number of consecutive RBs and the number of consecutive symbols of the CORESET of the Type0-PDCCH CSS set from controlResourceSetZero in pdcch-ConfigSIB1. The UE may also determine the PDCCH monitoring opportunity from searchSpaceZero in pdcch-ConfigSIB1. For example, for an SSB with index i, searchSpaceZero may provide the system frame number (SFN) of the frame of the relevant CORESET. C ; and SFN C The corresponding frame includes the first time slot of the Type-0 monitoring opportunity, time slot n0; and the parameter value combination required to determine the index of the first symbol of the corresponding CORESET in time slot n0. The UE can monitor the Type0-PDCCH CSS set in the PDCCH monitoring opportunity to detect the SIB1 PDCCH. The UE can determine the frequency resource allocation and time resource allocation of the SIB1 PDSCH from the DCI carried by the SIB1 PDCCH. The UE can receive / decode SIB1 based on the frequency resource allocation and the time resource allocation.

[0179] Due to battery capacity, power saving of UE has always been one of the key issues in the field of communications, and various technologies have been developed for UE power saving. For example, in the RRC_CONNECTED state, the UE's PDCCH monitoring operation (hereinafter referred to as DCP) is managed by discontinuous reception (DRX), bandwidth adaptation (BA), and DCI with CRC scrambled by power saving RNTI (PS-RNTI), where PS-RNTI is used to determine whether the UE needs to monitor the PDCCH during the next occurrence of the CONNECTED mode DRX on duration. As another example, UE power saving in the RRC_IDLE / RRC_INACTIVE state can be achieved by providing a configuration of a tracking reference signal (TRS) as a CSI-RS for tracking at the TRS opportunity. TRS is a set of RS designed to assist UEs in time and frequency tracking, and during the TRS opportunity, TRS can allow UEs in the RRC_IDLE / RRC_INACTIVE state to sleep for a longer duration before waking up for a paging opportunity.

[0180] Generally, under the assumption that the BS has no power limitation, energy saving of the BS is not a major issue in the field of communications compared to energy saving of the UE. However, due to its potential contribution to building an environmentally friendly network by reducing carbon emissions and cutting the operating expenditure (OPEX) of communication operators, energy saving of the BS is significantly considered in wireless communication systems including 3GPP. In particular, as the demand for high transmission rates continues to escalate with the emergence of 5G communications, the BS needs to be equipped with a larger number of antennas and provide services in a wider bandwidth and frequency band. According to recent studies, the energy cost of the BS has reached as high as 20% of the total OPEX. Due to the increased attention to BS energy saving, 3GPP NR Release 18 approved a new research project called "Network Energy Saving Research". For example, in order to enhance the energy-saving capabilities in terms of transmission and reception of the BS, this study investigates how to use potential support / feedback from the UE and potential UE support information based on one or more network energy-saving technologies with a finer adaptive granularity to dynamically and / or semi-statically achieve more efficient transmission and / or reception operations in the time, frequency, space and power domains.

[0181] The BS may switch to sleep mode and perform symbol muting (i.e., energy saving through discontinuous transmission (DTX)) during a time period when there is no data to be transmitted / received or in a light load condition. However, common (or cell common) signals such as SSB, which are essential for synchronization, initial access, and measurement of UEs, always need to be transmitted as always-on signals and cannot be symbol muted. In order to transmit signals, the BS should periodically switch from sleep mode to active mode. Therefore, from the perspective of energy saving of the BS, it is difficult to achieve significant gain from transitioning to sleep mode.

[0182] In NR, SSB / SIB can be transmitted on multiple beams based on a specific subcarrier spacing (SCS) and beam sweeping for each frequency range (FR). As the FR increases, the number of beams increases. As a result, the amount of time resources used to transmit common signals / channels such as SSB / SIB1 in FR2 becomes relatively larger compared to FR1, which may result in a higher proportion of energy consumption of the BS.

[0183] Fig.12 A scenario in which a macro cell and a small cell are carrier aggregated is shown.

[0184] Reference Fig.12 In a CA environment between a macro P(S)Cell and a small SCell (e.g., a combination of a PCell for 15kHz SCS and an SCell for 120kHz SCS), if the difference between the distance between the UE and the macro cell and the distance between the UE and the small cell exceeds about 175 meters, the propagation delay may become greater than the CP length (586ns) of the 120kHz SCS. In such a CA scenario, a frame boundary misalignment exceeding the CP length may occur between the PCell and the SCell, and a development signal is required to compensate for the misalignment.

[0185] Table 5 is an excerpt from the standard document 3GPP 38.133. According to the following Table 5, even in intra-band / inter-band CA within the same FR, timing misalignment greater than the CP may occur. In particular, for non-contiguous intra-band CA, in FR1, the maximum receive timing difference (MRTD) is 3μs, but in the case of 30 / 60kHz SCS, the timing misalignment may become greater than the CP length.

[0186] [Table 5]

[0187]

[0188] In order to solve these situations in the prior art, the UE needs to receive SSB and / or TRS on the SCell for obtaining fine time / frequency synchronization on the SCell. When the UE is first connected to the BS, the UE performs step-by-step time / frequency synchronization processing (for fine synchronization) using PSS, SSS and TRS in the order of PSS->SSS->TRS. In the following, an implementation of the present disclosure is about a method for saving energy consumed by the BS when the BS sends a signal required for the UE to synchronize with a serving cell. According to an implementation of the present disclosure, the step-by-step processing for PSS / SSS / TRS can be reduced, or the signal required for the UE to obtain time / frequency synchronization can be reconfigured as compactly as possible in the time domain. For convenience, the set of signals sent by the BS for serving cell synchronization may be referred to as an energy saving discovery signal (ES-DRS).

[0189] In some implementations of the present specification, when the BS operates in the network energy saving (NES) mode for energy saving (ES), it means that the BS preconfigures multiple off periods (i.e., BSDTX periods) in which the transmission of a specific DL signal is turned off within a specific period. The BS dynamically indicates one of the off periods to indicate that the DL signal will not be sent during the predefined time period, thereby achieving power consumption saving for both the BS and the UE. The NES mode can be applied not only to the time domain, but also to the following operations in the frequency domain: BWP switching, dynamic RB adaptation, etc. For the spatial domain, the NES mode may refer to an operating mode in which the BS avoids performing transmission and / or reception on the corresponding antenna port to achieve power consumption reduction for both the BS and the UE when the BS semi-statically or dynamically disables a specific receiving antenna port.

[0190] <Method #1> Method of configuring ES-DRS with a combination of DL / UL signals by modifying the existing SSB structure

[0191] >(1-1) Method of maintaining PSS / SSS and replacing PBCH symbols with TRS (i.e., configuring ES-DRS with PSS+TRS+SSS+TRS)

[0192] >>A. In this case, by reducing the number of guard tones compared to the existing PSS / SSS (using a length 127 sequence), the PSS / SSS may consist of 11 PRBs.

[0193] >(1-2) Similar to RACH, the method of reconfiguring ES-DRS in the form of CP+sequence+sequence+...

[0194] >>A. Configure ES-DRS as CP+SSS+SSS+GP, CP+TRS+TRS+GP or CP+RACH+RACH+GP, where GP is a guard period without a signal and RACH is a (RACH) preamble code.

[0195] >>B. Method for configuring different repetition times of the sequence according to the situation (for example, the radius of the cell or the speed of the UE)

[0196] >>C. In this case, by reducing the number of guard tones compared to the existing SSS (using a length 127 sequence), the SSS can be composed of 11 PRBs.

[0197] >(1-3) Method for configuring ES-DRS through a combination of PSS / SSS

[0198] >A. Method of configuring ES-DRS in the form of PSS+PSS+SSS+SSS or PSS+SSS+SSS+PSS

[0199] >(1-4) When SSS is repeated and transmitted (twice or more times), a method of extending SSS-SCS to 30kHz while the data SCS is 15kHz so as to reduce the time area occupied by 2 symbols and configuring the 2-symbol area of ​​SSS to correspond to the 1-symbol area of ​​data (i.e., configuring the time domain length of 2 symbols of SSB to be the same as the time domain length of 1-symbol area of ​​data)

[0200] >(1-5) A method of multiplexing TRS with ES-DRS whenever SSB is transmitted K times (eg, including TRS in the ES-DRS structure whenever SSB is transmitted K times).

[0201] However, method #1 may be applied when the UE is implemented with a single oscillator when supporting CA between PCell and SCell, thus allowing the assumption that the time / frequency error is below a certain level compared to the PCell.

[0202] The methods (1-1) to (1-5) are described in more detail below. Figures 13 to 15 The structure of an ES-DRS according to some implementations of the present disclosure is shown.

[0203] Fig.16 The structure of the SS / PBCH block is shown in FIG. The currently used SS / PBCH block (ie, SSB) is located in the time domain in the order of PSS+PBCH+SSS+PBCH. PSS and SSS are M sequences of length 127 and Gold sequences spanning 12 RBs, and PBCH is configured on 20 RBs around SSS. Fig.16 , SSB includes PSS, SSS and PBCH. PSS and SSS each occupy 1 OFDM symbol and 127 subcarriers, and PBCH spans 3 OFDM symbols and 240 subcarriers, except for 1 OFDM symbol in the middle that is left as an unused portion for SSS. When the UE first receives the SSB and performs the initial access procedure, the UE searches for the SSB frequency position SS corresponding to the global synchronization channel number (GSCN) according to the frequency range in which the UE operates. REF The synchronization raster of SSB is sent, and then the system information is acquired. The UE obtains the symbol timing and the cell ID within the cell group from the PSS, and detects the cell group based on the SSS. Next, the UE can determine the SSB index and the half frame (HF) index based on the DM-RS included in the PBCH (that is, the UE can detect the time slot and frame boundaries). By decoding the PBCH, the UE obtains the time information (80ms (PBCH TTI), SFN, SSB index, HF, etc.) and RMSI CORESET / search space configuration from the MIB. In this way, the UE performs cell access and time / frequency synchronization through PSS, SSS and PBCH.

[0204] like Fig.16 As shown in FIG. 1 , the PSS and SSS composed of a length 127 sequence use 127 REs in 12 RBs for PSS and SSS mapping. Among the 127 REs, 17 subcarriers are reserved as guard subcarriers.

[0205] As previously explained, in a CA environment between a macro P(S)Cell and a small SCell, if the difference between the distance between the UE and the macro cell and the distance between the UE and the small cell is greater than approximately 175 meters, the propagation delay may become greater than the CP length (586ns) of a 120kHz SCS. Therefore, a signal may be required to compensate for frame boundary misalignment exceeding the CP length between the PCell and the SCell. Therefore, in order to achieve fine time / frequency synchronization of the SCell, the UE may use an ES-DRS configured with a combination of DL / UL signals (as compactly as possible) by modifying the existing SSB structure for time / frequency synchronization acquisition, rather than receiving the existing SSB and / or TRS on the SCell.

[0206] As a first method of configuring ES-DRS, it is possible to consider maintaining the current structure of PSS / SSS and replacing PBCH symbols with TRS. In other words, instead of the current time domain signal configuration of SSB (i.e., PSS+PBCH+SSS+PBCH), ES-DRS can be configured as PSS+TRS+SSS+TRS, such as Fig.13 As shown. Although not shown, by reducing the number of protection tones compared to the existing PSS / SSS (using a length 127 sequence), the PSS / SSS may be composed of 11 PRBs. In addition, considering the frequency synchronization resolution of the ES-DRS, the ES-DRS may also be configured in a structure that maintains a 4-symbol TRS interval, for example, {beam 1PSS+beam 1TRS+beam 1SSS+beam 2TRS}+{beam 2PSS+beam 1TRS+beam 2SSS+beam 2TRS},... In this case, beam indexes such as beam 1, beam 2, etc. may be replaced with SSB indexes. Alternatively, beam 1 and beam 2 may be different beams with different SSB indexes, or beam 1 and beam 2 may have the same beam index (e.g., beams of a QCL relationship).

[0207] As another method, it may be considered to reconfigure the ES-DRS in the form of CP+sequence+sequence+... similar to the current RACH.

[0208] Fig.17 and Fig.18 An exemplary PRACH preamble format is shown.

[0209] The current PRACH preamble uses a long sequence and a short sequence. The PRACH preamble using a short sequence of length 139 is configured in the form of CP+sequence or CP+sequence+sequence+..., such as Fig.17 and Fig.18 shown.

[0210] According to the PRACH preamble format, such as Fig.17 and Fig.18 As shown, format A is configured in the form of CP+sequence+sequence, format B is configured in the form of CP+sequence+sequence+GP, and format C is configured in the form of CP+sequence+GP. These various PRACH preamble formats are designed taking into account factors such as the size of the cell or high-speed scenarios where the UE moves quickly. The PRACH preamble format can be selected and used according to the environment of the UE and the cell.

[0211] Therefore, similar to the PRACH preamble format, Fig.14 As shown, a method of configuring ES-DRS in the form of CP+SSS+SSS+GP, CP+TRS+TRS+GP or CP+RACH+RACH+GP may be considered. The number of repetitions of the sequence of the above structure may be configured differently for transmission according to the size of the cell or the speed of the UE. In addition, although not shown, by reducing the number of guard tones compared to the existing structure, the SSS may be composed of 11 PRBs.

[0212] Next, a method of configuring ES-DRS based on a PSS / SSS combination may also be considered. For example, an additional PSS / SSS may be placed at the position of the PBCH in the current SSB structure. If the method in (1-1) is in the form of {PSS+TRS+SSS+TRS}, such as Fig.15As shown, the ES-DRS can be configured in the form of {PSS+PSS+SSS+SSS} or {PSS+SSS+SSS+PSS}, and there may be differences between them in terms of frequency synchronization. For example, in the case of {PSS+SSS+SSS+PSS}, there is a distance of 1-OFDM symbol (e.g., the distance between PSS and SSS) and 3-OFDM symbol (e.g., the distance between PSS and PSS), so frequency synchronization can be achieved by first acquiring it with a 1-OFDM symbol distance and then reducing the residual error with a 3-OFDM symbol distance. Taking this structure into account, the BS may additionally send {PSS+PSS+SSS+SSS} or {PSS+PSS+SSS+(-)SSS} to allow the UE to perform blind detection, thereby allowing simple signaling (e.g., signaling the on / off state of the NES mode). Here, (-)SSS refers to the SSS mapped in the opposite direction. Similarly, when using the {PSS+SSS+SSS+PSS} structure, the BS may send {PSS+SSS+SSS+PSS} or {PSS+SSS+(-)SSS+PSS} to allow the UE to perform blind detection, thereby allowing simple signaling (e.g., signaling the on / off state of the NES mode).

[0213] On the other hand, when the new ES-DRS structure is used based on the PSS / SSS combination, it may lead to the possibility of failure of the traditional UE due to the newly added PSS / SSS. Therefore, as an alternative method, a structure of maintaining only one PSS and adding an additional SSS may also be considered. For example, a method of configuring the ES-DRS as {PSS+SSS+SSS+SSS} may be considered, and this structure may also provide similar performance to the method in (1-1) in terms of frequency synchronization. In this case, the BS may send {PSS+SSS+SSS+SSS} or {PSS+SSS+SSS+(-)SSS} to allow the UE to perform blind detection, thereby allowing simple signaling (for example, signaling the on / off state of the NES mode).

[0214] In the above method, when the SSS is repeated and transmitted, the SSS-SCS can be increased to 30kHz while the data SCS is 15kHz, so as to reduce the time area occupied by 2 symbols. This can configure the 2-symbol area of ​​the SSS to correspond to the 1-symbol area of ​​the data (that is, the time domain length of the 2 symbols of the SSB becomes the same as the time domain length of the 1-symbol area of ​​the data). In addition, the demand for TRS may vary according to the UE, and even for UEs that require TRS, TRS may not necessarily need to be sent as frequently as the SSB periodicity. Therefore, as described in the method in (1-2) or (1-3), a TRS-less ES-DRS is possible, or a structure in which TRS is multiplexed with ES-DRS and sent every time SSB is sent K times can also be considered (especially in the case of the method in (1-1)). Alternatively, the periodicity of the TRS included in the ES-DRS can be configured / sent with a periodicity shorter than that of the SSB.

[0215] <Method #2> Method for signaling ES-DRS burst structure and method for determining signal power constituting ES-DRS

[0216] >(2-1) A method for signaling a time domain ES-DRS burst structure by sending an SSB index in the form of a bitmap when the SSB symbol duration is similar to the existing SSB symbol duration in (1-1) or (1-3) of method #1, similar to using a bitmap to signal the actual transmitted SSB index (refer to Figure 8 )

[0217] >>A. Configure the bandwidth (BW) of the TRS to be the same as the BW of the SCell BWP, or if the continuous ES-DRS burst structure is advantageous in terms of NES, additionally configure the BW of the TRP by signaling only the number of bursts

[0218] >(2-2) If a new structure is introduced as in (1-2) of method #1, the signaling method may depend on the number of symbols in the ES-DRS.

[0219] >>A. For 2-symbol ES-DRS, the ES-DRS burst structure can be signaled, where 7 consecutive symbols or the last few symbols in one time slot are reserved for UL, and 6 consecutive symbols are placed in the time slot.

[0220] >(2-3) For 4-symbol DRS as in (1-1) and (1-3) of method #1

[0221] >>A. An ES-DRS burst structure may be signaled where 3 consecutive DRSs are placed consecutively within a single time slot (with a gap of 2 symbols) (e.g., 4 symbol DRS + 2 symbol gap + 4 symbol DRS + 2 symbol gap + 4 symbol DRS or 4 symbol DRS + 4 symbol DRS + 4 symbol DRS + 2 symbol gap + 2 symbol gap).

[0222] >(2-4) Method for determining the power of signals constituting ES-DRS

[0223] >>A. The TRS replacing the PBCH is assumed to have the same power as the SSS

[0224] A. >> B. Assuming the same power as PSS (because there is no PBCH part)

[0225] >>C. Method of determining power value through separate configuration.

[0226] >(2-5) Method for signaling ES-DRS configuration information of neighboring cells when ES-DRS is used for neighboring cell measurement The methods in (2-1) to (2-5) are described in more detail below.

[0227] When ES-DRS is configured as in (1-1) or (1-3) of method #1, in the existing SSB structure of {PSS+PBCH+SSS+PBCH}, the positions of PSS and SSS symbols may remain the same, and TRS, PSS and / or SSS may be placed at the position of PBCH. If the SSB symbol duration is similar to the existing SSB symbol duration, signaling the time domain ES-DRS burst structure may be fully implemented by simply indicating the transmitted SSB index in the form of a bitmap (i.e., in the form of ssb-PositionsInBurst within SIB1 or ServingCellConfigCommon) similar to informing the actual transmitted SSB index. Alternatively, when a continuous ES-DRS burst structure is advantageous in terms of NES, a method of signaling only the number of bursts may also be feasible (if the structure of the ES-DRS arrangement within the time slot is known). In this case, the BW of the TRS may be set to be the same as the BW of the SCell BWP, or the BW of the TRS may be configured separately.

[0228] On the other hand, if a new structure different from the existing SSB is introduced as in (1-2) of method #1, various ES-DRS burst structures may be possible depending on the number of symbols in the ES-DRS. For example, in the case of a 2-symbol ES-DRS, the ES-DRS burst may be configured by leaving 7 consecutive symbols or the last few symbols in a time slot for UL and placing 6 consecutive symbols in the time slot. Alternatively, in the case of a 4-symbol DRS as in (1-1) and (1-3) of method #1, the ES-DRS may be configured by placing 3 consecutive DRSs consecutively in a single time slot (with a gap of 2 symbols) (e.g., 4-symbol DRS+2 symbol gaps+4-symbol DRS+2 symbol gaps+4-symbol DRS or 4-symbol DRS+4-symbol DRS+4-symbol DRS+2 symbol gaps+2 symbol gaps).

[0229] Next, for the PSS and SSS included in the SSB, the UE may assume that the ratio of the PSS per resource element energy (EPRE) to the SSS EPRE is 0 dB or 3 dB. That is, the power of the PSS may be increased by 0 or 3 dB compared to the SSS, or the same power may be assumed for the SSB and PBCH. Similarly, for the signal power included in the ES-DRS, three options may be considered: i) a method in which the TRS replacing the PBCH is assumed to have the same power as the SSS; ii) a method in which the power is assumed to be the same as the PSS (because there is no PBCH part); or iii) a method in which the power value is determined by a separate configuration. In addition, if the ES-DRS is used for neighboring cell measurements, the BS may also signal the ES-DRS configuration information of the neighboring cell (e.g., the structure of the ES-DRS, the burst configuration, and the signal power included in the ES-DRS).

[0230] According to some implementations of the present disclosure, since PBCH is not included in ES-DRS, the BS does not perform PBCH encoding, which is beneficial to energy saving. In addition, according to some implementations of the present disclosure, since there is no need to send PBCH that occupies more RBs than SSS and PSS, the transmission of ES-DRS can consume less power compared to the transmission of SSB.

[0231] According to some implementations of the present disclosure, the energy consumed by the BS when sending the ES-DRS required for serving cell synchronization may be saved.

[0232] Even when the BS operates in NES mode, if the ES-DRS required for the UE to maintain or acquire time / frequency synchronization with the cell needs to be provided at the SSB opportunity of the corresponding cell, the BS may need to send the ES-DRS at a large number of SSB opportunities within a specific frequency range (e.g., FR2). Therefore, according to some implementations of the present disclosure, the ES-DRS can be sent to the UE in the cell at each SSB opportunity of the cell with less energy consumption compared to SSB transmission.

[0233] Fig.19 The flow of DL signal reception at a UE according to some implementations of the present disclosure is shown. Fig. 20 A flow of DL signal transmission at a BS according to some implementations of the present disclosure is shown.

[0234] exist Fig.19 and Fig. 20 The first type of SSB is the SSB according to the current NR standard (refer to Fig.16 ), the second type SSB is an ES-DRS configured according to one of the methods / implementations described in method #1. As described above, the first type SSB may be sent periodically (e.g., with a periodicity of 20ms), and the second type SSB may be sent with the same periodicity as the first type SSB or with a periodicity longer than the periodicity of the first type SSB. Fig.19 and Fig. 20 , the second mode is the NES mode, and the first mode is the general mode rather than the NES mode, that is, the non-NES mode.

[0235] The UE may perform operations according to some implementations of the present disclosure in association with DL signal reception. The UE may include: at least one transceiver; at least one processor; and at least one computer memory, which is operatively connectable to the at least one processor and stores instructions, which when executed, cause the at least one processor to perform operations according to some implementations of the present disclosure. A processing device for a UE may include: at least one processor; and at least one computer memory, which is operatively connectable to the at least one processor and stores instructions, which 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 including instructions, which 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 include instructions, which are recorded on at least one computer-readable (non-transitory) storage medium and when executed, cause (at least one processor) to perform operations according to some implementations of the present disclosure.

[0236] Reference Fig.19, the method performed by the UE or the operation of the UE, the processing device, the computer-readable (non-transitory) storage medium and / or the computer program product may include: monitoring a first type SSB for a first mode on a cell (S1901); based on detecting the first type SSB, obtaining time and frequency synchronization with the cell from the first type SSB; based on the transition from the first mode to the second mode (S1903), monitoring a second type SSB on the cell (S1905); and based on detecting the second type SSB, obtaining time and frequency synchronization with the cell from the second type SSB. Among the four consecutive OFDM symbols for the first type SSB, the first type SSB may include a PSS in the first OFDM symbol, an SSS in the third OFDM symbol, and a PBCH in the second to fourth OFDM symbols, while leaving a portion for the SSS in the third OFDM symbol. The second type SSB has a different structure from the first type SSB. For example, the second type SSB may be the ES-DRS described in method #1.

[0237] The BS may perform operations according to some implementations of the present disclosure in association with DL signal transmission. The BS may include: at least one transceiver; at least one processor; and at least one computer memory, which is operatively connectable to the at least one processor and stores instructions, which when executed, cause the at least one processor to perform operations according to some implementations of the present disclosure. A processing device for a BS may include: at least one processor; and at least one computer memory, which is operatively connectable to the at least one processor and stores instructions, which 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 including instructions, which 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 include instructions, which are recorded on at least one computer-readable (non-transitory) storage medium and when executed, cause (at least one processor) to perform operations according to some implementations of the present disclosure.

[0238] Reference Fig. 20, the method performed by the BS or the operation of the BS, the processing device, the computer-readable (non-transitory) storage medium and / or the computer program product may include: sending a first type SSB for a first mode on a cell (S2001); and based on the transition from the first mode to the second mode (S2003), sending a second type SSB on the cell (S2005). Among the four consecutive OFDM symbols for the first type SSB, the first type SSB may include a PSS in the first OFDM symbol, an SSS in the third OFDM symbol, and a PBCH in the second to fourth OFDM symbols, while leaving a portion for the SSS in the third OFDM symbol. The second type SSB has a different structure from the first type SSB. For example, the second type SSB may be the ES-DRS described in method #1.

[0239] The examples of the present disclosure as described above have been presented to enable those of ordinary skill in the art to implement and practice the present disclosure. Although the present disclosure is described with reference to the examples, those skilled in the art may make various modifications and changes in the examples of the present disclosure. Therefore, the present disclosure is not intended to be limited to the examples set forth herein, but to conform to the widest scope consistent with the principles and features disclosed herein.

[0240] Implementations of the present disclosure may be used in a BS, a UE, or other devices in a wireless communication system.

Claims

1. A method for receiving a downlink signal by a user equipment UE in a wireless communication system, the method comprising the following steps: Monitoring a first type of synchronization signal block SSB for a first pattern on the cell; acquiring time and frequency synchronization with the cell via the first type of SSB based on detecting the first type of SSB; monitoring a second type of SSB on the cell based on transitioning from the first mode to a second mode; as well as acquiring time and frequency synchronization with the cell via the second type SSB based on detecting the second type SSB, Among them, among the four consecutive orthogonal frequency division multiplexing OFDM symbols for the first type SSB, the first type SSB includes a primary synchronization signal PSS in the first OFDM symbol, a secondary synchronization signal SSS in the third OFDM symbol, and a physical broadcast channel PBCH in the second OFDM symbol to the fourth OFDM symbol, and a part is reserved for the SSS in the third OFDM symbol, and The second type SSB has a structure different from that of the first type SSB.

2. The method according to claim 1, wherein: Among four consecutive OFDM symbols for the second type SSB, the second type SSB includes the PSS in the first OFDM symbol, the SSS in the third OFDM symbol, and tracking reference signals TRS in the second and fourth OFDM symbols.

3. The method according to claim 1, wherein: The second type SSB occupies fewer resource blocks than the resource blocks occupied by the PSS and the SSS of the first type SSB.

4. The method according to claim 1, wherein: The second type SSB consists of a cyclic prefix CP, at least one random access preamble code and a guard period GP.

5. The method according to claim 1, wherein: The second type of SSB includes: i) the PSS in the first and second OFDM symbols and the SSS in the third and fourth OFDM symbols among four consecutive OFDM symbols for the second type SSB; or ii) the PSS in the first and fourth OFDM symbols and the SSS in the second and third OFDM symbols among the four consecutive OFDM symbols for the second type SSB.

6. The method according to claim 5, wherein: The second type SSB applies a subcarrier spacing to the SSS that is twice the subcarrier spacing for a physical downlink shared channel on the cell.

7. The method according to claim 1, wherein: The second mode is a network energy saving mode.

8. A user equipment UE configured to receive a downlink signal in a wireless communication system, the UE comprising: at least one transceiver; at least one processor; as well as at least one computer memory operatively connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations comprising: Monitoring a first type of synchronization signal block SSB for a first pattern on the cell; acquiring time and frequency synchronization with the cell from the first type of SSB based on detecting the first type of SSB; Based on the transition from the first mode to the second mode, monitoring a second type of SSB on the cell; and acquiring time and frequency synchronization with the cell from the second type SSB based on detecting the second type SSB, Among them, among the four consecutive orthogonal frequency division multiplexing OFDM symbols for the first type SSB, the first type SSB includes a primary synchronization signal PSS in the first OFDM symbol, a secondary synchronization signal SSS in the third OFDM symbol, and a physical broadcast channel PBCH in the second OFDM symbol to the fourth OFDM symbol, and a part is reserved for the SSS in the third OFDM symbol, and The second type SSB has a structure different from that of the first type SSB.

9. A processing device in a wireless communication system, the processing device comprising: at least one processor; as well as at least one computer memory operatively connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations comprising: Monitoring a first type of synchronization signal block SSB for a first pattern on the cell; acquiring time and frequency synchronization with the cell from the first type of SSB based on detecting the first type of SSB; Based on the transition from the first mode to the second mode, monitoring a second type of SSB on the cell; and acquiring time and frequency synchronization with the cell from the second type SSB based on detecting the second type SSB, Among them, among the four consecutive orthogonal frequency division multiplexing OFDM symbols for the first type SSB, the first type SSB includes a primary synchronization signal PSS in the first OFDM symbol, a secondary synchronization signal SSS in the third OFDM symbol, and a physical broadcast channel PBCH in the second OFDM symbol to the fourth OFDM symbol, and a part is reserved for the SSS in the third OFDM symbol, and The second type SSB has a structure different from that of the first type SSB.

10. A computer-readable storage medium configured to store at least one program code comprising instructions that, when executed, cause at least one processor to perform operations comprising: Monitoring a first type of synchronization signal block SSB for a first pattern on the cell; acquiring time and frequency synchronization with the cell from the first type of SSB based on detecting the first type of SSB; monitoring a second type of SSB on the cell based on transitioning from the first mode to a second mode; as well as acquiring time and frequency synchronization with the cell from the second type SSB based on detecting the second type SSB, Among them, among the four consecutive orthogonal frequency division multiplexing OFDM symbols for the first type SSB, the first type SSB includes a primary synchronization signal PSS in the first OFDM symbol, a secondary synchronization signal SSS in the third OFDM symbol, and a physical broadcast channel PBCH in the second OFDM symbol to the fourth OFDM symbol, and a part is reserved for the SSS in the third OFDM symbol, and The second type SSB has a structure different from that of the first type SSB.

11. A method for sending a downlink signal by a base station BS to a user equipment UE in a wireless communication system, the method comprising the following steps: Sending a first type of synchronization signal block SSB on the cell; as well as transmitting a second type of SSB on the cell based on the transition from the first mode to the second mode, Among them, among the four consecutive orthogonal frequency division multiplexing OFDM symbols for the first type SSB, the first type SSB includes a primary synchronization signal PSS in the first OFDM symbol, a secondary synchronization signal SSS in the third OFDM symbol, and a physical broadcast channel PBCH in the second OFDM symbol to the fourth OFDM symbol, and a part is reserved for the SSS in the third OFDM symbol, and The second type SSB has a structure different from that of the first type SSB.

12. A base station BS configured to send a downlink signal to a user equipment UE in a wireless communication system, the BS comprising: at least one transceiver; at least one processor; as well as at least one computer memory operatively connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations comprising: Sending a first type of synchronization signal block SSB on the cell; and transmitting a second type of SSB on the cell based on the transition from the first mode to the second mode, Among them, among the four consecutive orthogonal frequency division multiplexing OFDM symbols for the first type SSB, the first type SSB includes a primary synchronization signal PSS in the first OFDM symbol, a secondary synchronization signal SSS in the third OFDM symbol, and a physical broadcast channel PBCH in the second OFDM symbol to the fourth OFDM symbol, and a part is reserved for the SSS in the third OFDM symbol, and The second type SSB has a structure different from that of the first type SSB.

13. The BS according to claim 12, wherein: Among four consecutive OFDM symbols for the second type SSB, the second type SSB includes the PSS in the first OFDM symbol, the SSS in the third OFDM symbol, and tracking reference signals TRS in the second and fourth OFDM symbols.

14. The BS according to claim 12, wherein: The second type SSB occupies fewer resource blocks than the resource blocks occupied by the PSS and the SSS of the first type SSB.

15. The BS according to claim 12, wherein: The second type SSB consists of a cyclic prefix CP, at least one random access preamble code and a guard period GP.

16. The BS according to claim 12, wherein: The second type of SSB includes: i) the PSS in the first and second OFDM symbols and the SSS in the third and fourth OFDM symbols among four consecutive OFDM symbols for the second type SSB; or ii) the PSS in the first and fourth OFDM symbols and the SSS in the second and third OFDM symbols among the four consecutive OFDM symbols for the second type SSB.

17. The BS according to claim 16, wherein: The second type SSB applies a subcarrier spacing to the SSS that is twice the subcarrier spacing for a physical downlink shared channel on the cell.

18. The BS according to claim 12, wherein: The second mode is a network energy saving mode.

Images