Synchronization signal management method and apparatus for power saving

Abstract

The present disclosure provides a method and an apparatus for operations of a terminal and a base station when a period or a pattern related to the transmission of a synchronization signal is changed with respect to a synchronization signal transmission control management method for power saving.

Description

Method and device for managing synchronization signals for power saving

[0001] The present disclosure relates to a technique for controlling synchronous signal transmission for power saving in wireless communication.

[0002] 3GPP NR requires that at least one synchronization signal block (SSB) be transmitted within two frames (20 ms). However, in cases where no users are accessing the cell, for example, the base station will spend all its power solely on repetitive transmission of the synchronization signal.

[0003] Furthermore, with the proliferation of small cells and other devices, energy-saving measures for these cells are becoming a critical factor for telecommunications operators. In particular, with various improved technologies, such as beamforming and AI prediction, being integrated into telecommunications operations, the need for more efficient power usage is growing.

[0004] From this perspective, the need to introduce power-saving technologies for periodically transmitted synchronization signals is growing. In particular, analysis suggests that power savings of up to 90% are possible when power for synchronization signals is efficiently controlled.

[0005] However, the synchronization signal is a signal used by the terminal to connect to the cell, and can affect various communication schemes such as downlink data signal transmission and reception and channel status information reporting depending on the periodic transmission of the synchronization signal.

[0006] In this situation, detailed operational plans are needed to ensure that power-saving technologies for synchronization signals can provide practical power-saving effects while minimizing their impact on existing communication technologies.

[0007] The present disclosure proposes detailed operations of a terminal and a base station according to synchronization signal control for power saving.

[0008] In one aspect, the present embodiments may provide a method for a terminal to receive a synchronization signal, the method including the steps of receiving change information on a transmission period or transmission pattern of a synchronization signal from a base station, the step of monitoring the synchronization signal based on the change information, and the step of receiving downlink data or a downlink reference signal in consideration of a change in the transmission period or transmission pattern of the synchronization signal according to the change information.

[0009] In another aspect, the present embodiments may provide a method in which a base station transmits a synchronization signal, the method including a step of transmitting change information on a transmission period or transmission pattern of the synchronization signal to a terminal and a step of determining a transmission resource of the synchronization signal or downlink data based on the change information.

[0010] In another aspect, the present embodiments may provide a terminal device that receives a synchronization signal, including a receiving unit that receives change information on a transmission period or transmission pattern of a synchronization signal from a base station, and a control unit that monitors the synchronization signal based on the change information, wherein the receiving unit receives downlink data or a downlink reference signal by considering a change in the transmission period or transmission pattern of the synchronization signal according to the change information.

[0011] In another aspect, the present embodiments can provide a base station device including a transmitter that transmits change information on a transmission period or transmission pattern of a synchronization signal to a terminal, and a control unit that determines a transmission resource of the synchronization signal or downlink data based on the change information, in a base station that transmits a synchronization signal.

[0012] The present disclosure can provide detailed operations of a terminal and a base station according to synchronization signal control for power saving.

[0013] FIG. 1 is a schematic diagram illustrating the structure of an NR wireless communication system to which the present embodiment can be applied.

[0014] FIG. 2 is a drawing for explaining a frame structure in an NR system to which the present embodiment can be applied.

[0015] FIG. 3 is a diagram for explaining a resource grid supported by a wireless access technology to which the present embodiment can be applied.

[0016] FIG. 4 is a diagram for explaining a bandwidth part supported by a wireless access technology to which the present embodiment can be applied.

[0017] FIG. 5 is a diagram illustrating an example of a synchronization signal block in a wireless access technology to which the present embodiment can be applied.

[0018] FIG. 6 is a diagram for explaining a random access procedure in a wireless access technology to which the present embodiment can be applied.

[0019] Figure 7 is a drawing for explaining CORESET.

[0020] Figure 8 is a drawing for explaining terminal operation according to one embodiment.

[0021] FIG. 9 is a diagram for explaining base station operation according to one embodiment.

[0022] FIG. 10 is a diagram illustrating GSCN (Global Synchronization Channel Number) parameters for each channel bandwidth according to one embodiment.

[0023] FIG. 11 is a diagram illustrating GSCN (Global Synchronization Channel Number) parameters for each channel bandwidth according to another embodiment.

[0024] FIG. 12 is a diagram illustrating GSCN (Global Synchronization Channel Number) parameters for each channel bandwidth according to another embodiment.

[0025] Fig. 13 is a drawing showing a terminal configuration according to one embodiment.

[0026] Fig. 14 is a diagram showing a base station configuration according to one embodiment.

[0027] Hereinafter, some embodiments of the present disclosure will be described in detail with reference to exemplary drawings. When adding reference numerals to components in each drawing, identical components may have the same numerals as much as possible even if they are shown in different drawings. In addition, when describing the present embodiments, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the technical idea of ​​the present invention, the detailed description may be omitted. When "includes," "has," "consists of," etc. are used in this specification, other parts may be added unless "only" is used. When a component is expressed in the singular, it may include a case in which the plural is included unless specifically stated otherwise.

[0028] Additionally, terms such as first, second, A, B, (a), (b), etc. may be used to describe components of the present disclosure. These terms are only intended to distinguish the components from other components, and the nature, order, sequence, or number of the components are not limited by the terms.

[0029] In a description of the positional relationship of components, when it is described that two or more components are "connected," "combined," or "connected," it should be understood that the two or more components may be directly "connected," "combined," or "connected," but that the two or more components may also be further "interposed" with another component to be "connected," "combined," or "connected." Here, the other component may be included in one or more of the two or more components that are "connected," "combined," or "connected" to each other.

[0030] In the description of the temporal flow relationship related to components, operation methods, or manufacturing methods, for example, when the temporal or flow relationship is described as “after”, “following”, “next to”, “before”, etc., it may also include cases where it is not continuous, unless “immediately” or “directly” is used.

[0031] Meanwhile, when numerical values ​​or corresponding information (e.g., levels, etc.) for components are mentioned, even without separate explicit description, the numerical values ​​or corresponding information may be interpreted as including an error range that may occur due to various factors (e.g., process factors, internal or external impact, noise, etc.).

[0032] The wireless communication system in this specification refers to a system for providing various communication services such as voice, data packets, etc. using wireless resources, and may include a terminal, a base station, or a core network.

[0033] The embodiments disclosed below can be applied to wireless communication systems using various wireless access technologies. For example, the embodiments can be applied to various wireless access technologies such as CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), SC-FDMA (single carrier frequency division multiple access), or NOMA (non-orthogonal multiple access). In addition, the wireless access technology may not only refer to a specific access technology, but also to each generation of communication technologies established by various communication agreement organizations such as 3GPP, 3GPP2, WiFi, Bluetooth, IEEE, and ITU. For example, CDMA can be implemented with wireless technologies such as UTRA (universal terrestrial radio access) or CDMA2000. TDMA can be implemented with wireless technologies such as GSM (global system for mobile communications) / GPRS (general packet radio service) / EDGE (enhanced data rates for GSM evolution). OFDMA can be implemented in wireless technologies such as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and E-UTRA (evolved UTRA). IEEE 802.16m is an evolution of IEEE 802.16e and provides backward compatibility with systems based on IEEE 802.16e.UTRA is part of UMTS (universal mobile telecommunications system). 3GPP (3rd generation partnership project) LTE (long term evolution) is part of E-UMTS (evolved UMTS) that uses E-UTRA (evolved-UMTSterrestrial radio access), employing OFDMA in the downlink and SC-FDMA in the uplink. Thus, the present embodiments can be applied to currently disclosed or commercialized wireless access technologies, as well as wireless access technologies currently under development or to be developed in the future.

[0034] Meanwhile, the term "terminal" in this specification is a comprehensive concept that refers to a device that includes a wireless communication module that performs communication with a base station in a wireless communication system, and should be interpreted as a concept that includes not only UE (User Equipment) in WCDMA, LTE, NR, HSPA, and IMT-2020 (5G or New Radio), but also MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), and wireless device in GSM. In addition, the terminal may be a user portable device such as a smartphone depending on the usage type, and in a V2X communication system, it may mean a vehicle, a device including a wireless communication module in the vehicle, etc. In addition, in the case of a Machine Type Communication system, it may mean an MTC terminal, M2M terminal, URLLC terminal, etc. that is equipped with a communication module to perform machine type communication.

[0035] The base station or cell in this specification refers to an end that communicates with a terminal in terms of a network, and includes various coverage areas such as Node-B, eNB (evolved Node-B), gNB (gNode-B), LPN (Low Power Node), Sector, Site, various types of antennas, BTS (Base Transceiver System), Access Point, Point (e.g., Transmission Point, Reception Point, Transmission / Reception Point), Relay Node, Mega Cell, Macro Cell, Micro Cell, Pico Cell, Femto Cell, RRH (Remote Radio Head), RU (Radio Unit), and Small Cell. In addition, a cell may mean including a BWP (Bandwidth Part) in the frequency domain. For example, a serving cell may mean an Activation BWP of a terminal.

[0036] Since the various cells listed above have a base station that controls one or more cells, the base station can be interpreted in two meanings. 1) It can be a device itself that provides a mega cell, macro cell, micro cell, pico cell, femto cell, or small cell in relation to a wireless area, or 2) it can indicate the wireless area itself. In 1), all devices that provide a given wireless area are controlled by the same entity or that interact to cooperatively configure the wireless area are all indicated as a base station. Depending on how the wireless area is configured, a point, a transceiver point, a transmission point, a reception point, etc. can be an embodiment of a base station. In 2), the wireless area itself that receives or transmits a signal from the perspective of a user terminal or a neighboring base station can also be indicated as a base station.

[0037] In this specification, a cell may mean a component carrier having coverage of a signal transmitted from a transmission / reception point or a transmission / reception point itself.

[0038] Uplink (UL, or uplink) refers to a method of transmitting and receiving data from a terminal to a base station, and downlink (DL, or downlink) refers to a method of transmitting and receiving data from a base station to a terminal. Downlink may refer to communication or a communication path from multiple transmission / reception points to a terminal, and uplink may refer to communication or a communication path from a terminal to multiple transmission / reception points. In this case, in the downlink, the transmitter may be part of the multiple transmission / reception points, and the receiver may be part of the terminal. In addition, in the uplink, the transmitter may be part of the terminal, and the receiver may be part of the multiple transmission / reception points.

[0039] Uplink and downlink transmit and receive control information through control channels such as PDCCH (Physical Downlink Control CHannel) and PUCCH (Physical Uplink Control CHannel), and transmit and receive data by configuring data channels such as PDSCH (Physical Downlink Shared CHannel) and PUSCH (Physical Uplink Shared CHannel). Hereinafter, the situation in which signals are transmitted and received through channels such as PUCCH, PUSCH, PDCCH, and PDSCH is also expressed in the form of 'transmitting and receiving PUCCH, PUSCH, PDCCH, and PDSCH.'

[0040] For clarity of explanation, the technical idea of ​​this invention is described below mainly with reference to the 3GPP LTE / LTE-A / NR (New RAT) communication system, but the technical features of this invention are not limited to the communication system.

[0041] After researching 4G (4th-Generation) communication technology, 3GPP develops 5G (5th-Generation) communication technology to meet the requirements of the next-generation wireless access technology of the ITU-R. Specifically, 3GPP develops LTE-A pro, which is an enhancement of LTE-Advanced technology to meet the requirements of the ITU-R, as a 5G communication technology, and NR, a new communication technology separate from 4G communication technology. Both LTE-A pro and NR refer to 5G communication technology, and in the following, 5G communication technology will be explained with NR as the focus, unless a specific communication technology is specified.

[0042] The operating scenario in NR defines various operation scenarios by adding considerations for satellites, automobiles, and new verticals to the existing 4G LTE scenario, and in terms of service, it supports the eMBB (Enhanced Mobile Broadband) scenario, the mMTC (Massive Machine Communication) scenario that has high terminal density but is deployed over a wide area and requires low data rate and asynchronous access, and the URLLC (Ultra Reliability and Low Latency) scenario that requires high responsiveness and reliability and can support high-speed mobility.

[0043] To meet these scenarios, NR introduces a wireless communication system that incorporates new waveform and frame structure technologies, low latency technologies, support for ultra-high frequency bands (mmWave), and forward compatibility technologies. In particular, NR systems offer various technological changes in terms of flexibility to ensure forward compatibility. The key technical features of NR are described below with reference to the drawings.

[0044] <NR 시스템 일반>

[0045] Figure 1 is a schematic diagram illustrating the structure of an NR system to which the present embodiment can be applied.

[0046] Referring to Fig. 1, the NR system is divided into 5GC (5G Core Network) and NR-RAN parts, and the NG-RAN is composed of gNBs and ng-eNBs that provide user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocol termination for UE (User Equipment). gNBs or gNBs and ng-eNBs are interconnected via the Xn interface. gNBs and ng-eNBs are each connected to the 5GC via the NG interface. The 5GC can be configured to include an AMF (Access and Mobility Management Function) that is responsible for the control plane such as terminal access and mobility control functions, and an UPF (User Plane Function) that is responsible for the control function for user data. NR includes support for both frequency bands below 6 GHz (FR1, Frequency Range 1) and frequency bands above 6 GHz (FR2, Frequency Range 2).

[0047] gNB refers to a base station that provides NR user plane and control plane protocol termination to terminals, and ng-eNB refers to a base station that provides E-UTRA user plane and control plane protocol termination to terminals. The base station described in this specification should be understood to encompass both gNB and ng-eNB, and may also be used to refer to gNB or ng-eNB separately as needed.

[0048] <NR 웨이브 폼,뉴머롤러지 및 프레임 구조>

[0049] NR uses the CP-OFDM waveform with a cyclic prefix for downlink transmission, and CP-OFDM or DFT-s-OFDM for uplink transmission. OFDM technology is easily combined with MIMO (Multiple Input Multiple Output) and offers the advantages of high spectral efficiency and low-complexity receivers.

[0050] Meanwhile, in NR, the requirements for data rates, latency, and coverage differ across the three scenarios mentioned above. Therefore, it is necessary to efficiently satisfy these requirements across the frequency bands that comprise any NR system. To this end, technologies have been proposed to efficiently multiplex radio resources based on multiple different numerologies.

[0051] Specifically, the NR transmission numerator is determined based on the sub-carrier spacing and the cyclic prefix (CP), and is changed exponentially using the μ value as an exponent value of 2 based on 15 kHz, as shown in Table 1 below.

[0052] μsubcarrier intervalCyclic prefixSupported for dataSupported for synch015NormalYesYes130NormalYesYes260Normal, ExtendedYesNo3120NormalYesYes4240NormalNoYes

[0053] As shown in Table 1 above, the numerology of NR can be divided into five types according to the subcarrier spacing. This is different from the fixed 15 kHz subcarrier spacing of LTE, one of the 4G communication technologies. Specifically, the subcarrier spacing used for data transmission in NR is 15, 30, 60, and 120 kHz, and the subcarrier spacing used for synchronization signal transmission is 15, 30, 120, and 240 kHz. In addition, the extended CP is applied only to the 60 kHz subcarrier spacing. Meanwhile, the frame structure in NR is defined as a 10 ms frame consisting of 10 subframes of the same length of 1 ms. One frame can be divided into 5 ms half frames, and each half frame contains 5 subframes. In the case of a 15 kHz subcarrier spacing, one subframe consists of one slot, and each slot consists of 14 OFDM symbols. FIG. 2 is a diagram for explaining the frame structure in an NR system to which the present embodiment can be applied.

[0054] Referring to Fig. 2, a slot is fixedly composed of 14 OFDM symbols in the case of a normal CP, but the length of the slot in the time domain may vary depending on the subcarrier spacing. For example, in the case of a numerology with a 15 kHz subcarrier spacing, a slot is composed of 1 ms in length, which is the same length as a subframe. In contrast, in the case of a numerology with a 30 kHz subcarrier spacing, a slot is composed of 14 OFDM symbols, but two slots may be included in one subframe with a length of 0.5 ms. In other words, subframes and frames are defined with fixed time lengths, while slots are defined by the number of symbols, and their time lengths may vary depending on the subcarrier spacing.

[0055] Meanwhile, NR defines slots as the basic scheduling unit and also introduces mini-slots (or sub-slots, or non-slot-based scheduling) to reduce transmission delay in the wireless section. Using wider subcarrier spacing reduces transmission delay in the wireless section by shortening the length of each slot inversely. Mini-slots (or sub-slots) are designed to efficiently support URLLC scenarios and allow scheduling in units of 2, 4, or 7 symbols.

[0056] Furthermore, unlike LTE, NR defines uplink and downlink resource allocation at the symbol level within a single slot. To reduce HARQ delay, a slot structure was defined that allows HARQ ACK / NACK to be transmitted directly within the transmission slot. This slot structure is referred to as a self-contained structure and will be described in detail.

[0057] NR is designed to support a total of 256 slot formats, of which 62 are used in 3GPP Rel-15. It also supports a common frame structure that configures FDD or TDD frames through various combinations of slots. For example, it supports a slot structure in which all symbols in a slot are set to downlink, a slot structure in which all symbols are set to uplink, and a slot structure in which downlink and uplink symbols are combined. NR also supports data transmission being distributed and scheduled across one or more slots. Therefore, a base station can use a slot format indicator (SFI) to inform a UE whether a slot is a downlink slot, an uplink slot, or a flexible slot. The base station can indicate the slot format by indicating an index of a table configured through UE-specific RRC signaling using the SFI, and can also indicate it dynamically through DCI (Downlink Control Information) or statically or semi-statically through RRC.

[0058] <NR 물리 자원 >

[0059] In relation to physical resources in NR, antenna ports, resource grids, resource elements, resource blocks, and bandwidth parts are considered.

[0060] Antenna ports are defined such that the channel through which a symbol on an antenna port is carried can be inferred from the channel through which another symbol on the same antenna port is carried. Two antenna ports are said to be quasi co-located (QC / QCL) if the large-scale properties of the channel through which a symbol on one antenna port is carried can be inferred from the channel through which a symbol on the other antenna port is carried. Here, the large-scale properties include one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.

[0061] FIG. 3 is a diagram for explaining a resource grid supported by a wireless access technology to which the present embodiment can be applied.

[0062] Referring to Figure 3, a resource grid may exist for each numeral, as NR supports multiple numerals on the same carrier. Furthermore, resource grids may exist based on antenna ports, subcarrier spacing, and transmission direction.

[0063] A resource block (RB) consists of 12 subcarriers and is defined solely in the frequency domain. Furthermore, a resource element (RE) consists of one OFDM symbol and one subcarrier. Therefore, as shown in Figure 3, the size of a single RB can vary depending on the subcarrier spacing. NR also defines "Point A," which serves as a common reference point for the RB grid, as well as common RBs and virtual RBs.

[0064] FIG. 4 is a diagram for explaining a bandwidth part supported by a wireless access technology to which the present embodiment can be applied.

[0065] Unlike LTE, where the carrier bandwidth is fixed at 20 MHz, NR sets the maximum carrier bandwidth from 50 MHz to 400 MHz for each subcarrier interval. Therefore, it is not assumed that all terminals will use the entire carrier bandwidth. Accordingly, NR allows terminals to designate bandwidth parts (BWPs) within the carrier bandwidth, as illustrated in Figure 4. Furthermore, bandwidth parts are associated with a single numerology, consist of a subset of consecutive common resource blocks, and can be dynamically activated over time. Each terminal is configured with up to four bandwidth parts for both the uplink and downlink, and data is transmitted and received using the bandwidth parts activated at a given time.

[0066] In the case of a paired spectrum, the uplink and downlink bandwidth parts are set independently, and in the case of an unpaired spectrum, the downlink and uplink bandwidth parts are set in pairs so that they can share a center frequency to prevent unnecessary frequency re-tuning between downlink and uplink operations.

[0067] <NR 초기 접속>

[0068] In NR, a terminal performs cell search and random access procedures to connect to a base station and perform communication.

[0069] Cell search is a procedure in which a terminal synchronizes to the cell of a corresponding base station, obtains a physical layer cell ID, and obtains system information using the synchronization signal block (SSB) transmitted by the base station.

[0070] FIG. 5 is a diagram illustrating an example of a synchronization signal block in a wireless access technology to which the present embodiment can be applied.

[0071] Referring to FIG. 5, SSB is composed of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS), each occupying 1 symbol and 127 subcarriers, and a PBCH spanning 3 OFDM symbols and 240 subcarriers.

[0072] The terminal receives SSB by monitoring SSB in the time and frequency domain.

[0073] SSB can be transmitted up to 64 times in 5ms. Multiple SSBs are transmitted in different transmission beams within 5ms, and the terminal performs detection assuming that SSBs are transmitted every 20ms based on a specific beam used for transmission. The number of beams that can be used for SSB transmission within 5ms can increase as the frequency band increases. For example, up to 4 SSB beams can be transmitted below 3GHz, up to 8 in the frequency band between 3GHz and 6GHz, and up to 64 different beams can be used for SSB transmission in the frequency band above 6GHz.

[0074] SSB contains two symbols in one slot, and the starting symbol and number of repetitions within the slot are determined as follows depending on the subcarrier spacing.

[0075] Meanwhile, unlike SS in conventional LTE, SSB is not transmitted at the center frequency of the carrier bandwidth. This means that SSB can be transmitted even in locations other than the center of the system bandwidth, and when supporting wideband operation, multiple SSBs can be transmitted in the frequency domain. Accordingly, the terminal monitors SSB using the synchronization raster, which is a candidate frequency location for monitoring SSB. The carrier raster, which is the center frequency location information of the channel for initial access, and the synchronization raster are newly defined in NR. The synchronization raster has a wider frequency interval than the carrier raster, which can support the terminal's fast SSB search.

[0076] A UE can obtain the MIB through the PBCH of the SSB. The MIB (Master Information Block) includes the minimum information required for the UE to receive the remaining system information (RMSI, Remaining Minimum System Information) broadcast by the network. In addition, the PBCH may include information on the position of the first DM-RS symbol in the time domain, information for the UE to monitor SIB1 (e.g., SIB1 numerology information, information related to SIB1 CORESET, search space information, PDCCH-related parameter information, etc.), offset information between the common resource block and the SSB (the absolute position of the SSB within the carrier is transmitted through SIB1), etc. Here, the SIB1 numerology information is also applied equally to some messages used in the random access procedure for the UE to access the base station after completing the cell search procedure. For example, the numerology information of SIB1 may be applied to at least one of messages 1 to 4 for the random access procedure.

[0077] The aforementioned RMSI may refer to SIB1 (System Information Block 1), and SIB1 is broadcast periodically (e.g., every 160 ms) in the cell. SIB1 contains information necessary for the UE to perform the initial random access procedure and is periodically transmitted via PDSCH. In order for the UE to receive SIB1, it must receive numerology information used for SIB1 transmission and CORESET (Control Resource Set) information used for SIB1 scheduling via PBCH. The UE checks scheduling information for SIB1 using SI-RNTI in CORESET and acquires SIB1 on PDSCH according to the scheduling information. The remaining SIBs, excluding SIB1, may be transmitted periodically or upon request of the UE.

[0078] FIG. 6 is a diagram for explaining a random access procedure in a wireless access technology to which the present embodiment can be applied.

[0079] Referring to FIG. 6, once cell search is complete, the terminal transmits a random access preamble for random access to the base station. The random access preamble is transmitted via the PRACH. Specifically, the random access preamble is transmitted to the base station via the PRACH, which consists of consecutive radio resources in a specific slot that is periodically repeated. Generally, when a terminal initially accesses a cell, a contention-based random access procedure is performed, and when performing random access for beam failure recovery (BFR), a non-contention-based random access procedure is performed.

[0080] The terminal receives a random access response to the transmitted random access preamble. The random access response may include a random access preamble identifier (ID), an UL Grant (uplink radio resource), a temporary C-RNTI (Temporary Cell - Radio Network Temporary Identifier), and a TAC (Time Alignment Command). Since one random access response may include random access response information for one or more terminals, the random access preamble identifier may be included to indicate which terminal the included UL Grant, temporary C-RNTI, and TAC are valid for. The random access preamble identifier may be an identifier for the random access preamble received by the base station. The TAC may be included as information for the terminal to adjust uplink synchronization. The random access response may be indicated by a random access identifier on the PDCCH, i.e., an RA-RNTI (Random Access - Radio Network Temporary Identifier).

[0081] Upon receiving a valid random access response, the terminal processes the information contained in the random access response and performs scheduled transmission to the base station. For example, the terminal applies TAC and stores a temporary C-RNTI. Furthermore, using the UL Grant, the terminal transmits data stored in its buffer or newly generated data to the base station. In this case, information that identifies the terminal must be included.

[0082] Finally, the terminal receives a downlink message for contention resolution.

[0083] <NR CORESET>

[0084] The downlink control channel in NR is transmitted in a CORESET (Control Resource Set) with a length of 1 to 3 symbols, and transmits uplink / downlink scheduling information, SFI (Slot format Index), and TPC (Transmit Power Control) information.

[0085] To ensure system flexibility, NR introduced the CORESET concept. CORESET (Control Resource Set) refers to time-frequency resources for downlink control signals. A terminal can decode control channel candidates using one or more search spaces within the CORESET time-frequency resources. A QCL (Quasi CoLocation) assumption is established for each CORESET, which is used to inform the characteristics of analog beam direction in addition to the delay spread, Doppler spread, Doppler shift, and average delay assumed by the conventional QCL.

[0086] Figure 7 is a drawing for explaining CORESET.

[0087] Referring to Figure 7, a CORESET can exist in various forms within the carrier bandwidth within a single slot, and in the time domain, a CORESET can consist of up to three OFDM symbols. In addition, a CORESET is defined as a multiple of six resource blocks up to the carrier bandwidth in the frequency domain.

[0088] The first CORESET is indicated via the MIB as part of the initial bandwidth part configuration, allowing the terminal to receive additional configuration and system information from the network. After establishing a connection with the base station, the terminal can receive and configure one or more CORESET information via RRC signaling.

[0089] In this specification, the terms frequency, frame, subframe, resource, resource block, region, band, subband, control channel, data channel, synchronization signal, various reference signals, various signals or various messages related to NR (New Radio) may be interpreted in the past or present meaning or in various meanings used in the future.

[0090] The present disclosure provides terminal and base station operations according to power saving for synchronization signals in a 3GPP NR system. In particular, the present disclosure provides a method for managing a transmission environment in which a base station transmits synchronization signals less frequently than the required transmission cycles supported by existing standards in an environment where energy saving functions are performed, a method for a terminal to receive a modified synchronization signal, and a method for receiving downlink data or a downlink reference signal according to a modified synchronization signal.

[0091] 3GPP NR requires that at least one SSB (Synchronization Signal Block) be transmitted within two frames, or 20ms. However, in cases where there are no users accessing the cell, for example, the base station consumes all its power solely for the repetitive transmission of the synchronization signal. A study item in 3GPP Rel. 18, Network Energy Saving, analyzed that if this power could be efficiently reduced, power savings of up to 90% could be achieved. Based on these results, Rel. 19, Enhancements of Network Energy Saving for NR, the successor to 3GPP Rel. 18's Network Energy Saving item, proposed the following objectives:

[0092] 1. Specify procedures and signaling method(s) to support on-demand SSB SCell operation for UEs in connected mode configured with CA, for both intra- / inter-band CA.

[0093] · Specify triggering method(s) (select from UE uplink wake-up-signal using an existing signal / channel, cell on / off indication via backhaul, Scell activation / deactivation signaling)

[0094] · Note1: On-demand SSB transmission can be used by UE for at least SCell time / frequency synchronization, L1 / L3 measurements and SCell activation, and is supported for FR1 and FR2 in non-shared spectrum.

[0095]

[0096] 2. Study procedures and signaling method(s) to support on-demand SIB1 for UEs in idle / inactive mode, including: [RAN1 / 2 / 3]

[0097] · Triggering method by uplink wake-up-signal using an existing signal / channel.

[0098] · Wake-up-signal configuration provisioning to UE

[0099] - Note: No modification of SSB will be discussed under this objective

[0100] · Information exchange between gNBs at least for the configuration of wake-up signal, if necessary.

[0101] · Checkpoint for normative work in RAN#105

[0102]

[0103] 3. Specify adaptation of common signal / channel transmissions. [RAN1 / 2 / 3 / 4]

[0104] · Adaptation of SSB in time domain, e.g. adapting periodicity

[0105] · Adaptation of PRACH in time domain

[0106] · Study adaptation of PRACH in spatial domain, e.g. non-uniform PRACH resources per SSB, and specify if found beneficial

[0107] - This study is to be done in 2Q’2024 only

[0108] · Adaptation of paging occasions including confining the paging occasions in the time domain

[0109] - Note: there shall be no paging latency increase

[0110] · Note: there shall be no negative impact to legacy UEs, unless significant benefits are shown

[0111]

[0112] 4. Specify the corresponding core requirements, for the above features.

[0113] Accordingly, a specific operational scheme is needed to control the frequency and period of the synchronization signal. Conventional synchronization signals are standardized to be transmitted at specific symbol locations within a frame, based on a set of bandwidths defined by the subcarrier spacing supported by the frequency. Therefore, SSB has the following number of candidate transmission regions for each case.

[0114] - At frequencies lower than 3GHz of FR1, 4

[0115] - At frequencies above 3GHz of FR1, 8

[0116] - 64 at all frequencies of FR2

[0117] Among these, the area where the actual SSB is transmitted is transmitted in bitmap form through the ssb-PositionInBurst message in the ServingCellConfigCommon (SIB) within messages such as SIB1 and CellGropuConfig. This is used to allow the UE to exclude and receive the area in case of collision between the PDSCH transmission area and the SSB, and the UE does not assume that the value of the message changes in the cell.

[0118] The UE, which identifies the area where SSB is transmitted within the frame through this message, assumes that no data is transmitted due to the area, regardless of whether the reception is successful. This means that the area is not included in the PDSCH. More specifically, among OFDM symbols containing SSB, the PRB area containing the SSB is not included in the PDSCH.

[0119] Meanwhile, the periodically transmitted SSB is used not only as a synchronization signal but also for channel quality measurement. For example, the SSB index can be used as a resource cell in Radio Link Monitoring or CSI reporting. Among these, in the case of Radio Link Monitoring, the SSB resource is specified through the SSB-Index value set in RadioLinkMonitoringRS in RadioLinkMonitoringConfig, and in the case of CSI, the SSB resource is specified through the SSB-Index value in CSI-SSB-ResourceSet, and this ID is specified in CSI-ResourceConfig to specify the SSB resource and serve as a reference signal. The value and the position determined by it are treated as constants that do not change as long as the terminal maintains the connection. The CSI resource established through the setting is assigned an individual / group ID, and based on the ID, the resource setting for performing the terminal's channel quality feedback report is performed in CSI-ReportConfig. The setting is largely composed of a combination of the setting values ​​below.

[0120] - Report Setting ID

[0121] - Carrier ID

[0122] - CSI ID for Channel Measurement

[0123] - CSI ID for Interference Measurement

[0124] - Report type: periodic, semi-persistent, aperiodic

[0125] - In case of periodic or semi-periodic reports, period and PUCCH / PUSCH resource location information

[0126] - Report Quantity: Report contents · CRI, RI, PMI, CQI, RSRP, etc.

[0127] - Whether to report frequency division values ​​and each division area

[0128] - Measurement time limit information

[0129] - Codebook information

[0130] Thus, existing NR systems assume that synchronization signal transmission information remains constant within a single cell. However, if the synchronization signal transmission cycle or pattern is changed to conserve power, synchronization signal transmission information within a single cell may become variable. Consequently, different operations may be required in areas such as data transmission, channel quality, and radio link measurements related to synchronization signals.

[0131] Additionally, under existing NR systems, if a synchronization signal is not detected for 20 ms, the UE determines that there are no accessible cells in the band and searches for other bands. Furthermore, if the structure or transmission of the synchronization signal changes midway, such as when the ssb-PositionInBurst value changes, the UE will not be aware of this until it reconnects via random access.

[0132] In consideration of these points, the present disclosure provides a method for configuring a transmission environment when a base station transmits SSB with a wider period or when the SSB transmission pattern changes during a 3GPP NR system. In particular, the present disclosure provides a method for managing a PDSCH region related to an SSB with changed transmission settings, transmitting auxiliary information, and measuring channel outage. In addition, the present disclosure provides an operating method in an environment in which a base station can change an SSB period and a transmission pattern within a period in a 3GPP NR system. In particular, the present disclosure determines an environment in which the period or transmission pattern changes in order to reduce the amount of searches by a terminal, and provides an operating method in which the pattern changes periodically. In addition, the present disclosure provides a method for a base station to transmit SSB with a wider period and a method for changing an SSB transmission pattern during a 3GPP NR system. In particular, the present disclosure provides a method for increasing an SSB period in the form of a specific natural number, and a method for notifying a terminal that the ssb-PositionInBurst value has changed.

[0133] In summary, the present disclosure provides a method for notifying a terminal when an SSB transmission cycle or transmission pattern is changed, a method for reducing the amount of terminal searches for the transmission cycle or transmission pattern, and a method for utilizing reference signals, downlink data, etc. related thereto.

[0134] The synchronization signal described in this specification can be described by describing it as an SSB including a synchronization signal.

[0135] Figure 8 is a drawing for explaining terminal operation according to one embodiment.

[0136] Referring to FIG. 8, a method (S800) for a terminal to receive a synchronization signal may include a step of receiving change information on a transmission period or transmission pattern of a synchronization signal from a base station (S810).

[0137] For example, the change information may be received based on at least one of an RRC message, a DCI (Downlink Control Information), and a MAC information element. For example, the change information may be received by being included in an RRC message. For another example, the change information may be received by being included in a DCI or MAC CE. For another example, the change information may be configured through an RRC message and applied by being activated or indicated through a DCI or MAC CE. For another example, the change information may be included in the form of a new parameter in an SIB, etc.

[0138] Meanwhile, the change information may include at least one of the following information.

[0139] - A multiple of a period compared to a base value, a set of values ​​or a range of values, such a value, set of values ​​or range of values ​​can be expressed in integer form.

[0140] - A multiple of the period compared to the base value and a value, a set of values ​​or a range of values, of the number of valid SSB transmissions within the multiple, these values ​​can be expressed in the form of two integers.

[0141] - An index value selected from among the indices for predefined values ​​that indicate the changed cycle.

[0142] - Valid time for changing the cycle

[0143] - Start time of change of cycle, expressed as offset or frame value, etc.

[0144] In this way, change information can be transmitted to terminals through terminal-specific or group-common messages.

[0145] Meanwhile, the change information may include information on not only the transmission period of the synchronization signal but also the frame position of the synchronization signal transmitted within the period. In other words, the frame position refers to information that allows the terminal to determine in which frame the SSB is transmitted when the synchronization signal period changes.

[0146] For example, information about the frame position can be conveyed in the form of an integer or bitmap whose maximum value is a multiple of the transmission period. Alternatively, as an implicit measure, the frame position can be conveyed as a multiple of the transmission period, such that the transmission pattern before the change changes linearly.

[0147] Meanwhile, the change information may also indicate information about the transmission pattern.

[0148] The synchronization signal can change the SSB transmission pattern within the transmission cycle. The transmission pattern can change along with the transmission cycle, or the transmission pattern alone can change without changing the transmission cycle. For example, the transmission pattern indicates which of the 4 / 8 / 64 SSB candidate positions defined in the standard is actually used, and this transmission pattern can also change.

[0149] To change the transmission pattern, an RRC message may include information indicating whether the cell is one for which the SSB transmission pattern can be changed. The information may include at least one of the following: whether change is possible, information on the change unit or reference position, information on the change validity period or validity time, the changed SSB transmission pattern or expected pattern, and whether QCL is inherited. In addition, the RRC message may include relevant information for receiving a message containing change information, such as an RNTI and a search space.

[0150] After the terminal receives the RRC message, the terminal can explicitly or implicitly receive change information regarding a change in the synchronization signal transmission pattern from the base station. For example, the terminal can monitor whether the ssb-PositionInBirst value periodically transmitted through SIB1 has changed in order to detect a change in the transmission pattern. As another example, the terminal can receive triggering information indicating the configuration of a specific transmission pattern through DCI or MAC CE. The change information including the triggering information can include at least one of information regarding whether a change has occurred, information related to the position where the change is performed, information regarding the change validity time, information indicating the transmission pattern in the form of an index or bitmap, and whether QCL is inherited.

[0151] As another example, information about changes to transmission patterns can be delivered directly through newly defined RRC messages, SIB1, or cell group common configuration information, without configuration through prior RRC messages, etc.

[0152] As another example, information about changes to transmission patterns can be peered and transmitted with information about changes to transmission cycles. That is, change information can indicate changes to both transmission cycles and transmission patterns, and can be pre-configured and peered in a table format or similar.

[0153] The method for a terminal to receive a synchronization signal (S800) may include a step of monitoring the synchronization signal based on change information (S820).

[0154] For example, when a change in synchronization signal information is received, the terminal monitors the reception of the synchronization signal in the changed frame. Since synchronization signals can be used for purposes such as CSI reporting, the terminal must also monitor these. Furthermore, while other downlink data is not transmitted through the transmission resource where the synchronization signal is transmitted, downlink data, etc. may be transmitted through the transmission resource if the synchronization signal is changed. Therefore, the terminal must monitor this in consideration.

[0155] Meanwhile, even if the transmission period and / or transmission pattern for the synchronization signal is changed, the terminal can assume that the QCL relationship is maintained at the index of the changed synchronization signal that is identical to the index of the synchronization signal before the change. That is, when monitoring a synchronization signal that has been changed according to change information, the terminal can assume that the QCL relationship is maintained at the index that is identical to the index of the synchronization signal before the change. This means that the synchronization signal is monitored assuming that it is received through the same transmission beam pattern (index).

[0156] The method for a terminal to receive a synchronization signal (S800) may include a step of receiving downlink data or a downlink reference signal by considering a change in the transmission cycle or transmission pattern of the synchronization signal according to change information (S830).

[0157] For example, if the transmission period or transmission pattern of a synchronization signal changes, the terminal can receive downlink data by taking this into account. A PDSCH containing downlink data cannot be allocated on transmission resources where synchronization signals are transmitted. Furthermore, synchronization signals can also be used for channel status reporting.

[0158] Therefore, when the transmission period or transmission pattern of the synchronization signal is changed, the terminal must take this into consideration and perform downlink data reception or downlink reference signal (synchronization signal) reporting operations.

[0159] For example, even if a synchronization signal changes, downlink data can be configured not to be allocated to the transmission resources of the synchronization signal before the change. This is to ensure smooth reception of downlink data by terminals that are not notified or aware of the synchronization signal change.

[0160] As another example, if a synchronization signal changes, the transmission resources of the previous synchronization signal can be used for downlink data allocation. Therefore, the terminal must consider this when receiving downlink data.

[0161] As another example, if a synchronization signal is changed, the transmission resources of the synchronization signal before the change can be set to be allocated solely for redundant transmission to ensure downlink data redundancy. In other words, the transmission resources of the synchronization signal before the change can be used for redundant transmission of some downlink data by varying the redundancy version.

[0162] With respect to downlink reference signal reception, the pre-change synchronization signal transmission resources may not be used for CSI reporting. Alternatively, CSI reporting for the pre-change synchronization signal transmission resources may be configured to be triggered aperiodically so that the base station does not trigger it. For example, if a terminal transmits channel state information feedback using a synchronization signal as a downlink reference signal, periodic feedback for the channel state information feedback may be restricted, or the configuration information applied to the pre-change synchronization signal may be deactivated. In addition, the terminal may perform a downlink reference signal reception operation according to the detailed embodiments described below with respect to CSI reporting.

[0163] As described above, the terminal receives information about changes in the transmission cycle or transmission pattern of the synchronization signal and monitors the synchronization signal based on this information. It also performs operations related to synchronization signal changes, including receiving downlink data and receiving the synchronization signal as a reference signal.

[0164] FIG. 9 is a diagram for explaining base station operation according to one embodiment.

[0165] Referring to FIG. 9, a method (S900) in which a base station transmits a synchronization signal may include a step of transmitting change information on a transmission cycle or transmission pattern of the synchronization signal to a terminal (S910).

[0166] For example, the change information may be transmitted based on at least one of an RRC message, DCI (Downlink Control Information), and MAC information element. For example, the change information may be transmitted by being included in an RRC message. For another example, the change information may be transmitted by being included in a DCI or MAC CE. For another example, the change information may be configured through an RRC message and applied by being activated or indicated through a DCI or MAC CE. For another example, the change information may be included in the form of a new parameter in an SIB, etc.

[0167] Meanwhile, the change information may include at least one of the following information.

[0168] - A multiple of a period compared to a base value, a set of values ​​or a range of values, such a value, set of values ​​or range of values ​​can be expressed in integer form.

[0169] - A multiple of the period compared to the base value and a value, a set of values ​​or a range of values, of the number of valid SSB transmissions within the multiple, these values ​​can be expressed in the form of two integers.

[0170] - An index value selected from among the indices for predefined values ​​that indicate the changed cycle.

[0171] - Valid time for changing the cycle

[0172] - Start time of change of cycle, expressed as offset or frame value, etc.

[0173] In this way, change information can be transmitted to terminals through terminal-specific or group-common messages.

[0174] Meanwhile, the change information may include information on not only the transmission period of the synchronization signal but also the frame position of the synchronization signal transmitted within the period. In other words, the frame position refers to information indicating in which frame the SSB is transmitted when the period of the synchronization signal changes.

[0175] For example, information about the frame position can be conveyed in the form of an integer or bitmap whose maximum value is a multiple of the transmission period. Alternatively, as an implicit measure, the frame position can be conveyed as a multiple of the transmission period, such that the transmission pattern before the change changes linearly.

[0176] Meanwhile, the change information may also indicate information about the transmission pattern.

[0177] The synchronization signal can change the SSB transmission pattern within the transmission cycle. The transmission pattern can change along with the transmission cycle, or the transmission pattern alone can change without changing the transmission cycle. For example, the transmission pattern indicates which of the 4 / 8 / 64 SSB candidate positions defined in the standard is actually used, and this transmission pattern can also change.

[0178] To change the transmission pattern, an RRC message may include information indicating whether the cell is a cell in which the SSB transmission pattern can be changed. The information may include at least one of the following: whether change is possible, information on the change unit or reference position, information on the change validity period or validity time, the changed SSB transmission pattern or expected pattern, and whether QCL is inherited. In addition, the RRC message may include relevant information for transmitting a message including change information, such as an RNTI and a search space.

[0179] After transmitting an RRC message to a terminal, the base station can explicitly or implicitly transmit change information regarding a change in a synchronization signal transmission pattern to the terminal. For example, the terminal can monitor whether the ssb-PositionInBirst value periodically transmitted through SIB1 has changed in order to detect a change in the transmission pattern. As another example, the base station can transmit triggering information indicating the configuration of a specific transmission pattern through DCI or MAC CE. The change information including the triggering information can include at least one of information regarding whether a change has occurred, information related to the position where the change is performed, information regarding the change validity time, information indicating the transmission pattern in the form of an index or bitmap, and whether QCL is inherited.

[0180] As another example, information about changes to transmission patterns can be delivered directly through newly defined RRC messages, SIB1, or cell group common configuration information, without configuration through prior RRC messages, etc.

[0181] As another example, information about changes to transmission patterns can be peered with information about changes to transmission cycles and delivered. That is, change information can indicate changes to both transmission cycles and transmission patterns, and for this purpose, it can be peered and pre-configured on the terminal in a table format or similar.

[0182] Meanwhile, even if the transmission period and / or transmission pattern for the synchronization signal is changed, the terminal can assume that the QCL relationship is maintained at the index of the changed synchronization signal that is identical to the index of the synchronization signal before the change. That is, when monitoring a synchronization signal that has been changed according to change information, the terminal can assume that the QCL relationship is maintained at the index that is identical to the index of the synchronization signal before the change. This means that the synchronization signal is monitored assuming that it is received through the same transmission beam pattern (index).

[0183] The method (S900) for a base station to transmit a synchronization signal may include a step of determining a transmission resource of a synchronization signal or downlink data based on change information (S920).

[0184] For example, when a change in synchronization signal information is received, the terminal monitors the reception of the synchronization signal in the changed frame. Since synchronization signals can be used for purposes such as CSI reporting, the terminal must also monitor these. Furthermore, while other downlink data is not transmitted through the transmission resource where the synchronization signal is transmitted, downlink data, etc. may be transmitted through the transmission resource if the synchronization signal is changed. Therefore, the terminal must monitor this in consideration.

[0185] For example, if the transmission period or transmission pattern of a synchronization signal changes, the base station can determine downlink data transmission resources based on this change. PDSCHs containing downlink data cannot be allocated on transmission resources where synchronization signals are transmitted. Furthermore, synchronization signals can also be used for channel status reporting.

[0186] Therefore, when the transmission period or transmission pattern of the synchronization signal is changed, the terminal must take this into consideration and perform downlink data reception or downlink reference signal (synchronization signal) reporting operations.

[0187] For example, even if a synchronization signal changes, downlink data can be configured not to be allocated to the transmission resources of the synchronization signal before the change. This is to ensure smooth reception of downlink data by terminals that are not notified or aware of the synchronization signal change.

[0188] As another example, if a synchronization signal changes, the transmission resources of the previous synchronization signal can be used for downlink data allocation. Therefore, the terminal must consider this when receiving downlink data.

[0189] As another example, if a synchronization signal is changed, the transmission resources of the synchronization signal before the change can be set to be allocated solely for redundant transmission to ensure downlink data redundancy. In other words, the transmission resources of the synchronization signal before the change can be used for redundant transmission of some downlink data by varying the redundancy version.

[0190] In relation to downlink reference signal transmission, the pre-change synchronization signal transmission resources may not be used for CSI reporting. Alternatively, CSI reporting for the pre-change synchronization signal transmission resources may be configured to be triggered aperiodically so that the base station does not trigger it. For example, if a terminal transmits channel state information feedback using a synchronization signal as a downlink reference signal, periodic feedback for the channel state information feedback may be restricted, or the configuration information applied to the pre-change synchronization signal may be deactivated. In addition, the terminal may perform a downlink reference signal reception operation according to the detailed embodiments described below with respect to CSI reporting.

[0191] As described above, the base station transmits information about changes to the transmission cycle or transmission pattern of the synchronization signal and monitors the synchronization signal based on this information. It also performs downlink data transmission related to synchronization signal changes and synchronization signal transmission as a reference signal.

[0192] Below, detailed embodiments that can be performed by the aforementioned terminals and base stations are described in greater detail. Each embodiment described below can be performed by the terminals and base stations in any combination.

[0193]

[0194] An embodiment of changing the transmission of the synchronization signal (SSB)

[0195] First, we describe an embodiment of a method for a base station to transmit SSB signals at a wider frequency and to change the SSB transmission pattern during transmission. In particular, we provide a method for increasing the SSB frequency in the form of a specific natural number and a method for notifying a terminal of a change in the ssb-PositionInBurst value.

[0196] This embodiment is broadly explained by dividing it into (1) a method for changing an SSB transmission cycle and (2) a method for changing an SSB transmission pattern within a cycle.

[0197] (1) How to change the SSB transmission cycle

[0198] This method involves changing the SSB transmission cycle from the existing 20ms to a different cycle and notifying the terminal of this change. This can be divided into two methods: one that transmits the significantly changed cycle and the other that transmits the frame position of the SSB transmitted during the cycle transmission.

[0199] ① Method of transmitting the changed period: First, the channel through which the changed period is transmitted can be a method using a new DCI or MAC message. This can be a UE-specific or group-common message. Alternatively, it can be a new RRC message, or a message added to an existing RRC, such as a SIB or ServingCellConfigCommon. The message can include one or more of the following information:

[0200] - A multiple of a base value, a set of values, or a range of values, expressed in integer form.

[0201] - A multiple of the period compared to the base value and a value, set of values, or range of values, expressed in the form of two integers, the number of valid SSB transmissions within the multiple.

[0202] - An index value selected from among the indices for predefined values ​​that indicate the changed cycle.

[0203] - Valid time for changing the cycle

[0204] - Start time of cycle change, expressed as offset or frame value, etc.

[0205] When instructed by DCI or MAC, RRC Reconfiguration is not instructed to the terminal receiving the instruction, and an RRC message notifying the changed period to the new access terminal can be delivered through a message added within the existing RRC, such as SIB or ServingCellConfigCommon. When instructed by RRC, RRC Reconfiguration can be instructed to all terminals. When a candidate group of values ​​for determining the period is delivered by an RRC message, the index of the candidate group can be instructed by DCI or MAC. Alternatively, Activation / Deactivation of the period being changed can be instructed through DCI or MAC.

[0206] Alternatively, the SSB can be transmitted in a bitmap format, indicating which frames within a given unit cycle are involved. This can be frame-by-frame or two-frame-by-frame.

[0207] ② Method for transmitting the frame position of SSB transmitted during period transmission: This method is a method for a terminal to determine in which frame SSB is transmitted when the period of SSB is changed.

[0208] First, this can be explicitly indicated. This can be an integer whose maximum value is a multiple of the period, or a bitmap that represents the location where the SSB is transmitted. For example, if the period is k times, the frame where the SSB is transmitted can be represented as an integer between 0 and k-1 or 1 and k. This can correspond to the remainder of the system frame number divided by k or k * 2. Alternatively, the frame location where the SSB is transmitted can be represented as a bitmap of length k, or a constant length equal to the maximum period specified in the standard.

[0209] Alternatively, this can be expressed implicitly. For example, if the period is multiplied by k, the system frame number can be determined as a multiple of k or k*2, a frame whose remainder when the frame number is divided by k or k*2 for l less than k is l, or a plurality of them. For example, if the changed period is doubled so that 40ms becomes the new SSB period, the terminal can determine that the SSB exists in a frame whose remainder is divisible by 4 or a frame whose remainder is 1.

[0210] (2) How to change the SSB transmission pattern within a cycle

[0211] This embodiment is a method for changing the transmission pattern of SSB within a cycle. For example, this is a method for changing information on which of the 4 / 8 / 64 SSB candidate positions defined in the standard, previously transmitted via the ssb-PositionInBurst message, is actually being used, and transmitting this information to the terminal.

[0212] In general, the modified pattern can inherit the beam information of the original pattern. In other words, this means that the same index of the modified beam pattern is in a QCL relationship.

[0213] Alternatively, the changed SSB transmission pattern can be indicated only in a form that is always included in the existing pattern. In other words, the use of previously unused SSB indices can be prohibited in additional configuration candidate patterns. Here, the existing pattern can be a pattern defined by SIB or one of the candidate patterns conveyed by the corresponding RRC message. In the case where it is defined as a constant such as SIB, the length of the bitmap conveying the changed SSB pattern can be determined by the number of indices used for transmission in the original SSB pattern. For example, if two indices are configured to be used for transmission in SIB1, the indication can be conveyed as a bitmap of length 2.

[0214] Alternatively, it can be passed down in the form of a comb. To do this, the pattern can be recognized as an integer value and sent only in a specific multiple of the index value. This can be applied in combination with the existing pattern in the form of a bitwise AND operation. For example, if the existing ssb-PositionInBurst is 10110011 and the new pattern is indicated as 2, the final pattern can be 10100010, which is the AND of 10110011 and 10101010.

[0215] ① Method using a preset RRC message: First, the base station can define a message within an RRC message such as SIB or ServingCellConfigCommon that indicates whether the cell is one in which the transmission pattern of SSBs within the cycle can be changed. The message can convey one or more of the following information:

[0216] - Whether change is possible

[0217] - Change unit or reference position

[0218] - Change validity period or time

[0219] - Change SSB transmission pattern or expected patterns

[0220] - QCL inheritance or QCL relevance expressed by existing configured SSB index or CSI resource ID

[0221] - Related information for receiving change instruction messages such as RNTI and Search space

[0222] After the RRC transmission, the base station can explicitly or implicitly change the SSB transmission mode. If implicitly, the terminal can monitor changes in the ssb-PositionInBurst value through SIB1 or other means at regular intervals to track changes in the SSB transmission mode. This can be done for each change unit of the above message, or for each CSI reporting cycle based on the SSB-Index.

[0223] If explicitly performed, the base station may issue a triggering message via DCI or MAC signaling. This may be a UE-specific or group-common message and may include one or more of the following information:

[0224] - Whether to change

[0225] - Information about where the change will be made

[0226] - Change validity period or time

[0227] - Change SSB transmission pattern expressed as an index or bitmap

[0228] - QCL inheritance or QCL relevance expressed by existing configured SSB index or CSI resource ID

[0229] ② Direct transmission method without pre-configuration: The base station can directly transmit the changed transmission pattern. To do this, a new RRC message conveying this information, or a reconfiguration triggering message that reloads SIB1 or CellGroupConfig, can be sent via DCI or MAC signaling. This message can be a UE-specific or group-specific message, and, similar to the method above, can include one or more of the following information:

[0230] - Whether to change

[0231] - Information about where the change will be made

[0232] - Change validity period or time

[0233] - Changed SSB transmission pattern represented as a bitmap

[0234] - QCL inheritance or QCL relevance expressed by existing configured SSB index or CSI resource ID

[0235] ③ Method of conveying periodic information and patterns in the form of a joint message: While the period and pattern can be conveyed independently as separate messages, the method presented here allows a single message to determine both the period and pattern. To achieve this, preset values ​​for period and pattern changes are predefined in a table format, and Activation / Deactivation-related triggering is performed by conveying the index of the corresponding table.

[0236] Through these embodiments, the wireless base station can reduce power consumption for operation in environments with few users by reducing the number of synchronization signal blocks that must be transmitted compared to existing systems.

[0237]

[0238] Example of an operation method of Adaptive SSB

[0239] SSB can only be transmitted at a specific frequency, and the SSB center frequency at this time is defined as GSCN (Global Synchronization Channel Number) as follows.

[0240] FIG. 10 is a diagram illustrating GSCN (Global Synchronization Channel Number) parameters for each channel bandwidth according to one embodiment.

[0241] FIG. 11 is a diagram illustrating GSCN (Global Synchronization Channel Number) parameters for each channel bandwidth according to another embodiment.

[0242] FIG. 12 is a diagram illustrating GSCN (Global Synchronization Channel Number) parameters for each channel bandwidth according to another embodiment.

[0243] Referring to FIGS. 10 to 12, it can be seen that GSCN is determined and differentiated according to the channel bandwidth.

[0244] First, in this embodiment, (1) a method for limiting the settings of Adaptive SSB, (2) a method for changing the contents of Adaptive SSB, and (3) a method for operating the changed settings of Adaptive SSB are provided. Adaptive SSB used in this embodiment means an SSB in which the period of the SSB or the transmission pattern within the period is variable, unlike an SSB in which the same signal must be transmitted every 20 ms period in the existing NR, and this can be replaced with another term having the same or similar meaning. That is, Adaptive SSB can mean an SSB that is set so that the transmission period or transmission pattern of the aforementioned synchronization signal can be changed.

[0245] (1) Adaptive SSB setting limit method

[0246] In general, the longer the SSB cycle, the longer the required SSB search time for the terminal. This increases the connection complexity of the non-accessed terminal. This method provides a method to limit the environments in which Adaptive SSB can be transmitted to reduce the complexity of the terminal's connection attempt in an environment where Adaptive SSB is applied. This can be broadly divided into a method that limits the GSCN where Adaptive SSB is transmitted and a method that limits the SFN.

[0247] ① Method of limiting GSCN: This method is a method of limiting the GSCN on which Adaptive SSB can be transmitted. For example, a band where the period is 40ms and the user must perform scanning for 40ms can only be transmitted on a specific GSCN. This can be defined as a set of specific values. Or, this can be a case where the remainder when the GSCN is divided by a certain integer is a specific value(s). Or, for frequencies below 3GHz, this can be a case where M, which has a value of 1, 3, or 5, is a specific value(s). Or, for frequencies below 3GHz, this can be a case where the quotient when the GSCN is divided by 3 is a specific value(s), or the remainder when the value is divided by a certain integer is a specific value(s).

[0248] The restricted GSCN can be standardized, transmitted from an adjacent cell, or transmitted via SSB using another GSCN within the cell. These restrictions can be defined separately for each period and pattern adaptation characteristic.

[0249] ② Restricting SFNs: This method defines an SFN where SSB must be transmitted even in adaptive SSB. This can be useful in multi-cell environments where each cell shares an SFN. The SFN can be a set whose remainder is a specific value divided by an integer. Alternatively, it can be defined as a specific subset of a set of 1024. This value can be defined separately for each adaptive SSB period and pattern adaptation characteristic.

[0250] (2) How to change the contents of Adaptive SSB

[0251] This method transmits only specific SSB content in the case of Adaptive SSB. More specifically, in SSB locations where Adaptation has been set and SSB transmission has changed, only some of the SSB components—PSS, SSS, and PBCH—can be transmitted. For example, only the PSS can be transmitted, or only the PSS and SSS can be transmitted. The choice of which elements to transmit or not can vary by index, system frame, or value set during Adaptive configuration.

[0252] Example 1: When adaptation is applied and a number of SSBs among the SSBs transmitted in a specific frame are set to not be transmitted, only the PSS in the first SSB index can be transmitted.

[0253] Example 2: When adaptation is applied and a number of SSBs among the SSBs transmitted in a specific frame are set to not be transmitted, all SSBs can be transmitted only in the first SSB index and only PSSs can be transmitted in the remaining indices.

[0254] Example 3: When Adaptation is applied, only PSS can be transmitted in the changed index.

[0255] Example 4: When Adaptation is applied, PSS may be transmitted only in certain SFNs at certain indices, and nothing may be transmitted in the rest.

[0256] (3) How to change the Adaptive SSB settings

[0257] This method operates by periodically or aperiodically changing multiple adaptation patterns. To configure such operation, multiple patterns are defined in advance when configuring the adaptation pattern, and the application period for each pattern is set, the applicable SFN is set, or an index is assigned to each pattern and the pattern to be used is activated / deactivated through DCI or MAC signaling. For this purpose, a separate DCI can be defined, and in particular, it can be operated on a group common PDCCH, a separate search space can be defined, or an RNTI can be defined for this. In addition, QCL can be separated and inherited for each adaptation pattern. This means that the QCL relationship is determined not by the SSB index, but by the combination of the SSB index and the pattern index.

[0258] Example 1: When setting up Adaptive SSB, two patterns can be defined, and ssb-Index pattern 1 can be applied to a frame in which the value obtained by dividing a specific frame number by 2 is 0, and ssb-Index pattern 2 can be applied to a frame in which the value obtained by dividing a specific frame number by 2 is 1.

[0259] Example 2: If a value related to a specific frame number is not divisible by 5, only one SSB using a universal beam can be transmitted in that frame. In this case, it can be combined with method (2) to transmit only the PSS.

[0260] For Activation / Deactivation via DCI or MAC, the control message may contain one or more of the following information:

[0261] - Pattern index to apply

[0262] - Offset the time until the pattern is applied

[0263] - Frequency location to be applied, expressed as GSCN offset, etc.

[0264] - Pattern application validity period

[0265] - If it changes periodically, the index sequence of the changing pattern

[0266] Through these embodiments, a wireless base station can perform cell presence confirmation and synchronization processes with less complexity in an environment where the number of synchronization signal blocks that must be transmitted is reduced compared to existing systems.

[0267]

[0268] Example of Linked Operation with Downlink Data and Channel Status Reporting

[0269] This embodiment provides a method for configuring transmission environments when a base station transmits SSB at a wider frequency in a 3GPP NR system or when the SSB transmission pattern changes during transmission. In particular, methods for managing PDSCH areas related to SSBs with changed transmission settings, transmitting auxiliary information, and measuring channel outage are provided.

[0270] This embodiment provides (1) a method for determining a PDSCH region according to a changed pattern and period of SSB, (2) a method for transmitting terminal assistance information for changing an SSB transmission period / pattern, (3) a method for managing Radio Link Monitoring, and (4) a method for managing CSI-RS feedback.

[0271] (1) Method for determining PDSCH area according to changed pattern and cycle of SSB

[0272] This method provides a method for handling PDSCH collisions in a situation where the transmission areas of PDSCH and SSB overlap when SSB Adaptation, i.e., a setting is applied where SSB is not transmitted in the existing transmission space due to a change in the period or pattern, is applied. First, the existing SSB transmission space may not always be used as a PDSCH regardless of whether the change setting is applied. This method can be applied, for example, when the SSB index pattern or period is changed by additional RRC or DCI, and all terminals have the original SSB transmission information intact, separate from the changed SSB pattern.

[0273] Next, only the SSB transmission space where transmission is currently taking place can be used as a PDSCH, and the space where transmission is not taking place can be used as a PDSCH region. This can be used in cases where not all terminals may be aware of the original SSB transmission information, for example, when the index pattern is changed by changing the ssb-PositionInBurst value in a message such as SIB1 or CellGroupConfig. However, it can also be applied in cases where all terminals have the original SSB transmission information intact.

[0274] Additionally, to accommodate situations where some users may not receive the new configuration information, the PDSCH region that is secured when the pattern changes and SSB is not transmitted can operate in an additional allocation manner rather than the same as when there is no SSB. In other words, if the PDSCH scheduled for a specific UE is divided into regions A and B, and B is an area that was originally an SSB transmission region but no SSB is transmitted due to additional signaling, the TBS calculation can be determined by the number of resource elements of A in the same way as when an SSB transmission is configured, and additional redundancy corresponding to the next turn of the circular buffer can be transmitted in region B. This allows the UE to receive the index change information normally regardless of whether it has successfully received it, and only increases the reception probability of the UE that has successfully received it.

[0275] (2) Terminal auxiliary information transmission method for changing SSB transmission cycle / pattern

[0276] A terminal may transmit auxiliary information to a base station necessary for the base station to change the SSB cycle or pattern. This information may be transmitted as a preset request or periodically transmitted via UCI, MAC, or UE RRC, and may include one or more of the following information:

[0277] - ACK for setting change

[0278] - Notification of concerns about cell access failure or serious problems when operating with the above settings

[0279] - Request to change to a specific setting or revert to the original setting before the cycle / pattern change is applied.

[0280] - Preferred or significantly receivable SSB index or indices above a certain RSRP

[0281] - SSB index or indices that are not preferred or are received below a certain RSRP.

[0282] - Mobility-related information, or the maximum SSB cycle requested

[0283] (3) Radio Link Monitoring Management Method

[0284] By the RRC message RadioLinkMonitoringConfig, the terminal measures link quality using specific RSs including SSB. At this time, if some of the SSBs set by monitoring have Adaptation applied, i.e., if the period or index pattern changes and a time region where transmission is not performed is specified, the terminal may not perform quality measurement for RLM in that region. This can be operated in the form of excluding it from the report triggering conditions for quality measurement. For example, the condition of SSB transmission not being interrupted can be added through NES-related signaling, or the value of rsrp-ThresholdSSB can be operated as if it has changed to -infinity in the corresponding index or period of the SSB where transmission is interrupted.

[0285] (4) CSI-RS feedback management method

[0286] Through CSI-ResourceConfig, the terminal configures resources for measuring channel quality using specific RSs, including SSB. Based on these settings, the terminal configures CSI-ReportConfig to report back the channel quality results measured by the terminal. When Adaptation is applied to the SSB RS resource, the following methods can be implemented to prevent the terminal from reporting incorrect channel measurement information due to measurements based on untransmitted RSs.

[0287] ① How to change resource settings: The NES setting status or setting value can be transmitted in the CSI-SSB-ResourceSet within the CSI-ResourceConfig. This can include, for example, a valid cycle value from a predefined table, i.e., a cycle value that is always confirmed to be transmitted. Alternatively, a new value can be defined for resourceType within the CSI-ResourceConfig, or it can be expressed as a new message that indicates an additional resourceType.

[0288] Alternatively, the SSB to which Adaptation is applied may be restricted from periodically configuring resources, or the resources and feedback settings utilizing them may be disabled when Adaptation is configured.

[0289] ② How to change feedback settings: This method provides an operation method when the ssb-Index with adaptation applied is set as the reference signal for CSI Feedback. This can be distinguished when the feedback transmission settings are Periodic, Semi-persistent, or Aperiodic.

[0290] First, if the setting is Periodic, the corresponding setting can be rendered invalid. Alternatively, if only the period is changed, the transmission period can be adjusted to follow the changed transmission period. This can be, for example, aligned to the changed SSB transmission period, the larger of the two, or set to the least common multiple of the two. Alternatively, the report itself can be performed without change, but the reference signal can be repeatedly referenced to the last transmitted signal value. In this case, for measurements using the same resource, the terminal can skip feedback at that point.

[0291] In the case of Semi-persistent, the base station performs Activation or DCI triggering only when the transmission of the corresponding SSB is initiated or when SSB transmission is performed in the area to be referenced by the terminal. In addition, when the transmission of the SSB is stopped, Deactivation is performed unconditionally so that the terminal can properly perform the feedback operation only in the previous method without referring to other settings. Alternatively, in the case where only the period of SSB transmission is changed, it can follow the changed transmission period as in Periodic, or skip the feedback referring to the resources at the time of non-transmission.

[0292] In the case of aperiodic, the base station can issue a triggering message only when transmission of the corresponding SSB is initiated or when SSB transmission is made in the area to be referenced by the terminal.

[0293] Through the above embodiment, successful resource transmission and reception and channel quality measurement can be performed in an environment where the number of synchronization signal blocks transmitted by a wireless base station is reduced.

[0294]

[0295] For the sake of ease of understanding and explanation, not all combination examples are described. However, the aforementioned examples can be combined in any combination and implemented by terminals and base stations. Furthermore, the terms used in this specification are arbitrary names that are easily understood when referring to new terms. Furthermore, the present embodiments can be applied even when other terms with the same meaning are used.

[0296] Below, terminal and base station configurations capable of performing the aforementioned embodiments are described again with reference to the drawings. To avoid unnecessary duplication, the descriptions are brief. Combinations of the embodiments described above can be implemented by the terminal and base station devices described below.

[0297] Fig. 13 is a drawing showing a terminal configuration according to one embodiment.

[0298] Referring to FIG. 13, a terminal (1300) receiving a synchronization signal may include a receiving unit (1330) that receives change information on a transmission period or transmission pattern of a synchronization signal from a base station, and a control unit (1310) that monitors the synchronization signal based on the change information. The receiving unit (1330) may receive downlink data or a downlink reference signal by considering a change in the transmission period or transmission pattern of the synchronization signal according to the change information.

[0299] For example, the change information may be received based on at least one of an RRC message, a DCI (Downlink Control Information), and a MAC information element. For example, the change information may be received by being included in an RRC message. For another example, the change information may be received by being included in a DCI or MAC CE. For another example, the change information may be configured through an RRC message and applied by being activated or indicated through a DCI or MAC CE. For another example, the change information may be included in the form of a new parameter in an SIB, etc.

[0300] Meanwhile, the change information may include at least one of the following information.

[0301] - A multiple of a period compared to a base value, a set of values ​​or a range of values, such a value, set of values ​​or range of values ​​can be expressed in integer form.

[0302] - A multiple of the period compared to the base value and a value, a set of values ​​or a range of values, of the number of valid SSB transmissions within the multiple, these values ​​can be expressed in the form of two integers.

[0303] - An index value selected from among the indices for predefined values ​​that indicate the changed cycle.

[0304] - Valid time for changing the cycle

[0305] - Start time of change of cycle, expressed as offset or frame value, etc.

[0306] In this way, change information can be transmitted to terminals through terminal-specific or group-common messages.

[0307] Meanwhile, the change information may include information on not only the transmission period of the synchronization signal but also the frame position of the synchronization signal transmitted within the period. In other words, the frame position refers to information for the control unit (1310) to determine in which frame the SSB is transmitted when the period of the synchronization signal is changed.

[0308] For example, information about the frame position can be conveyed in the form of an integer or bitmap whose maximum value is a multiple of the transmission period. Alternatively, as an implicit measure, the frame position can be conveyed as a multiple of the transmission period, such that the transmission pattern before the change changes linearly.

[0309] Meanwhile, the change information may also indicate information about the transmission pattern.

[0310] The synchronization signal can change the SSB transmission pattern within the transmission cycle. The transmission pattern can change along with the transmission cycle, or the transmission pattern alone can change without changing the transmission cycle. For example, the transmission pattern indicates which of the 4 / 8 / 64 SSB candidate positions defined in the standard is actually used, and this transmission pattern can also change.

[0311] To change the transmission pattern, an RRC message may include information indicating whether the cell is one for which the SSB transmission pattern can be changed. The information may include at least one of the following: whether change is possible, information on the change unit or reference position, information on the change validity period or validity time, the changed SSB transmission pattern or expected pattern, and whether QCL is inherited. In addition, the RRC message may include relevant information for receiving a message containing change information, such as an RNTI and a search space.

[0312] After the terminal receives the RRC message, the receiving unit (1330) can explicitly or implicitly receive change information regarding a change in the synchronization signal transmission pattern from the base station. For example, the control unit (1310) can monitor whether the ssb-PositionInBirst value periodically transmitted through SIB1 has changed in order to detect a change in the transmission pattern. As another example, the receiving unit (1330) can receive triggering information indicating the configuration of a specific transmission pattern through DCI or MAC CE. The change information including the triggering information can include at least one of information regarding whether or not a change has occurred, information related to the location where the change is performed, information regarding the change validity time, transmission pattern indication information in the form of an index or bitmap, and whether or not QCL is inherited.

[0313] As another example, information about changes to transmission patterns can be delivered directly through newly defined RRC messages, SIB1, or cell group common configuration information, without configuration through prior RRC messages, etc.

[0314] As another example, information about changes to transmission patterns can be peered and transmitted with information about changes to transmission cycles. That is, change information can indicate changes to both transmission cycles and transmission patterns, and can be pre-configured and peered in a table format or similar.

[0315] Meanwhile, when change information regarding the synchronization signal is received, the control unit (1310) monitors the reception of the synchronization signal in the changed frame accordingly. The synchronization signal can be used for CSI reporting, etc., and the control unit (1310) must also monitor this. In addition, although other downlink data is not transmitted through the transmission resource where the synchronization signal is transmitted, downlink data, etc. may be transmitted through the transmission resource when the synchronization signal is changed. Therefore, the control unit (1310) must monitor this in consideration.

[0316] Meanwhile, the control unit (1310) may assume that the QCL relationship is maintained at the index of the changed synchronization signal that is the same as the index of the synchronization signal before the change, even if the transmission period and / or transmission pattern for the synchronization signal is changed. That is, when monitoring the synchronization signal changed according to the change information, the control unit (1310) may assume that the QCL relationship is maintained at the index that is the same as the index of the synchronization signal before the change. This means that monitoring is performed assuming that the synchronization signal is received through the same transmission beam pattern.

[0317] The receiver (1330) can receive downlink data by taking into account changes in the transmission cycle or transmission pattern of the synchronization signal. A PDSCH containing downlink data cannot be allocated in the transmission resources where the synchronization signal is transmitted. Furthermore, the synchronization signal may also be used for channel status reporting.

[0318] Therefore, when the transmission cycle or transmission pattern of the synchronization signal is changed, the control unit (1310) must take this into consideration and perform a downlink data reception or downlink reference signal (synchronization signal) reporting operation.

[0319] For example, even if a synchronization signal is changed, downlink data may be configured not to be allocated to the transmission resources of the synchronization signal before the change. This is to ensure smooth reception of downlink data by a terminal (1300) that is not notified or aware of a change in the synchronization signal.

[0320] As another example, if a synchronization signal is changed, the transmission resources of the synchronization signal before the change may be used for downlink data allocation. Therefore, the control unit (1310) must take this into account when receiving downlink data.

[0321] As another example, if a synchronization signal is changed, the transmission resources of the synchronization signal before the change can be set to be allocated solely for redundant transmission to ensure downlink data redundancy. In other words, the transmission resources of the synchronization signal before the change can be used for redundant transmission of some downlink data by varying the redundancy version.

[0322] In relation to downlink reference signal reception, the pre-change synchronization signal transmission resources may not be used for CSI reporting. Alternatively, CSI reporting for the pre-change synchronization signal transmission resources may be configured to be triggered aperiodically so that the base station does not trigger it. For example, if a terminal transmits channel state information feedback using a synchronization signal as a downlink reference signal, periodic feedback for the channel state information feedback may be restricted, or the configuration information applied to the pre-change synchronization signal may be deactivated. In addition, the receiver (1330) may perform a downlink reference signal reception operation according to the detailed embodiments described above with respect to CSI reporting.

[0323] In addition, the control unit (1310) controls the overall operation of the terminal (1300) according to the synchronization signal transmission control for power saving required to perform the aforementioned embodiment.

[0324] The transmitter (1320) and receiver (1330) are used to transmit and receive signals, messages, and data necessary for carrying out the present invention described above with the base station.

[0325] Fig. 14 is a diagram showing a base station configuration according to one embodiment.

[0326] Referring to FIG. 14, a base station (1400) that transmits a synchronization signal may include a transmission unit (1420) that transmits change information about a transmission period or transmission pattern of a synchronization signal to a terminal, and a control unit (1410) that determines a transmission resource of a synchronization signal or downlink data based on the change information.

[0327] For example, the change information may be transmitted based on at least one of an RRC message, DCI (Downlink Control Information), and MAC information element. For example, the change information may be transmitted by being included in an RRC message. For another example, the change information may be transmitted by being included in a DCI or MAC CE. For another example, the change information may be configured through an RRC message and applied by being activated or indicated through a DCI or MAC CE. For another example, the change information may be included in the form of a new parameter in an SIB, etc.

[0328] Meanwhile, the change information may include at least one of the following information.

[0329] - A multiple of a period compared to a base value, a set of values ​​or a range of values, such a value, set of values ​​or range of values ​​can be expressed in integer form.

[0330] - A multiple of the period compared to the base value and a value, a set of values ​​or a range of values, of the number of valid SSB transmissions within the multiple, these values ​​can be expressed in the form of two integers.

[0331] - An index value selected from among the indices for predefined values ​​that indicate the changed cycle.

[0332] - Valid time for changing the cycle

[0333] - Start time of change of cycle, expressed as offset or frame value, etc.

[0334] In this way, change information can be transmitted to terminals through terminal-specific or group-common messages.

[0335] Meanwhile, the change information may include information on not only the transmission period of the synchronization signal but also the frame position of the synchronization signal transmitted within the period. In other words, the frame position refers to information indicating in which frame the SSB is transmitted when the period of the synchronization signal changes.

[0336] For example, information about the frame position can be conveyed in the form of an integer or bitmap whose maximum value is a multiple of the transmission period. Alternatively, as an implicit measure, the frame position can be conveyed as a multiple of the transmission period, such that the transmission pattern before the change changes linearly.

[0337] Meanwhile, the change information may also indicate information about the transmission pattern.

[0338] The synchronization signal can change the SSB transmission pattern within the transmission cycle. The transmission pattern can change along with the transmission cycle, or the transmission pattern alone can change without changing the transmission cycle. For example, the transmission pattern indicates which of the 4 / 8 / 64 SSB candidate positions defined in the standard is actually used, and this transmission pattern can also change.

[0339] To change the transmission pattern, an RRC message may include information indicating whether the cell is a cell in which the SSB transmission pattern can be changed. The information may include at least one of the following: whether change is possible, information on the change unit or reference position, information on the change validity period or validity time, the changed SSB transmission pattern or expected pattern, and whether QCL is inherited. In addition, the RRC message may include relevant information for transmitting a message including change information, such as an RNTI and a search space.

[0340] After transmitting the RRC message to the terminal, the transmitter (1420) may explicitly or implicitly transmit change information regarding a change in the synchronization signal transmission pattern to the terminal. For example, the terminal may monitor whether the ssb-PositionInBirst value periodically transmitted through SIB1 has changed in order to detect a change in the transmission pattern. As another example, the transmitter (1420) may transmit triggering information indicating the configuration of a specific transmission pattern through DCI or MAC CE. The change information including the triggering information may include at least one of information regarding whether a change has occurred, information related to the location where the change is performed, information regarding the change validity time, transmission pattern indication information in the form of an index or bitmap, and whether QCL is inherited.

[0341] As another example, information about changes to transmission patterns can be delivered directly through newly defined RRC messages, SIB1, or cell group common configuration information, without configuration through prior RRC messages, etc.

[0342] As another example, information about changes to transmission patterns can be peered with information about changes to transmission cycles and delivered. That is, change information can indicate changes to both transmission cycles and transmission patterns, and for this purpose, it can be peered and pre-configured on the terminal in a table format or similar.

[0343] Meanwhile, even if the transmission period and / or transmission pattern for the synchronization signal is changed, the terminal can assume that the QCL relationship is maintained at the index of the changed synchronization signal that is identical to the index of the synchronization signal before the change. That is, when monitoring a synchronization signal that has been changed according to change information, the terminal can assume that the QCL relationship is maintained at the index that is identical to the index of the synchronization signal before the change. This means that the synchronization signal is monitored under the assumption that it is received through the same transmission beam pattern.

[0344] When a change in synchronization signal information is received, the terminal monitors the reception of the synchronization signal in the modified frame. Synchronization signals can be used for purposes such as CSI reporting, and the terminal must also monitor these. Furthermore, while other downlink data is not transmitted through the transmission resource where the synchronization signal is transmitted, changes to the synchronization signal may result in downlink data being transmitted through the transmission resource. Therefore, the terminal must monitor this in light of these changes.

[0345] For example, if the transmission period or transmission pattern of the synchronization signal changes, the control unit (1410) can determine downlink data transmission resources by taking this into consideration. A PDSCH containing downlink data cannot be allocated to transmission resources where the synchronization signal is transmitted. Furthermore, the synchronization signal may also be used for channel status reporting.

[0346] Therefore, when the transmission period or transmission pattern of the synchronization signal is changed, the terminal must take this into consideration and perform downlink data reception or downlink reference signal (synchronization signal) reporting operations.

[0347] For example, even if a synchronization signal changes, downlink data can be configured not to be allocated to the transmission resources of the synchronization signal before the change. This is to ensure smooth reception of downlink data by terminals that are not notified or aware of the synchronization signal change.

[0348] As another example, if a synchronization signal changes, the transmission resources of the previous synchronization signal can be used for downlink data allocation. Therefore, the terminal must consider this when receiving downlink data.

[0349] As another example, if a synchronization signal is changed, the transmission resources of the synchronization signal before the change can be set to be allocated solely for redundant transmission to ensure downlink data redundancy. In other words, the transmission resources of the synchronization signal before the change can be used for redundant transmission of some downlink data by varying the redundancy version.

[0350] In relation to downlink reference signal transmission, the pre-change synchronization signal transmission resources may not be used for CSI reporting. Alternatively, CSI reporting for the pre-change synchronization signal transmission resources may be configured to be triggered aperiodically so that the base station does not trigger it. For example, if a terminal transmits channel state information feedback using a synchronization signal as a downlink reference signal, periodic feedback for the channel state information feedback may be restricted, or the configuration information applied to the pre-change synchronization signal may be deactivated. In addition, the terminal may perform a downlink reference signal reception operation according to the detailed embodiments described above with respect to CSI reporting.

[0351] In addition, the control unit (1410) controls the overall operation of the base station (1400) according to the synchronization signal transmission control for power saving required to perform the aforementioned embodiment.

[0352] The transmitter (1420) and receiver (1430) are used to transmit and receive signals, messages, and data necessary for performing the aforementioned embodiment to and from the terminal.

[0353] The above-described embodiments may be supported by standard documents disclosed in at least one of the wireless access systems, IEEE 802, 3GPP, and 3GPP2. That is, steps, components, and parts not described in the present embodiments to clearly illustrate the technical concepts herein may be supported by the above-described standard documents. Furthermore, all terms disclosed in this specification may be explained by the above-described standard documents.

[0354] The embodiments described above may be implemented through various means. For example, the embodiments may be implemented through hardware, firmware, software, or a combination thereof.

[0355] In the case of hardware implementation, the method according to the present embodiments may be implemented by one or more ASICs (Application Specific Integrated Circuits), DSPs (Digital Signal Processors), DSPDs (Digital Signal Processing Devices), PLDs (Programmable Logic Devices), FPGAs (Field Programmable Gate Arrays), processors, controllers, microcontrollers, or microprocessors.

[0356] When implemented using firmware or software, the methods according to the present embodiments may be implemented in the form of devices, procedures, or functions that perform the functions or operations described above. The software code may be stored in a memory unit and executed by a processor. The memory unit may be located within or outside the processor and may exchange data with the processor using various known means.

[0357] Additionally, terms such as "system," "processor," "controller," "component," "module," "interface," "model," or "unit" as described above may generally refer to a computer-related entity, such as hardware, a combination of hardware and software, software, or software in execution. For example, the aforementioned components may be, but are not limited to, a process driven by a processor, a processor, a controller, a control processor, an object, a thread of execution, a program, and / or a computer. For example, both an application running on a controller or a processor and the controller or the processor may be components. One or more components may be within a process and / or thread of execution, and the components may be located on a single device (e.g., a system, a computing device, etc.) or distributed across two or more devices.

[0358] The above description is merely an illustrative example of the technical idea of ​​the present disclosure, and those skilled in the art to which the present disclosure pertains will appreciate that various modifications and variations can be made without departing from the essential characteristics of the technical idea of ​​the present disclosure. In addition, the present embodiments are not intended to limit the technical idea of ​​the present disclosure but rather to explain it, and therefore the scope of the technical idea of ​​the present disclosure is not limited by these embodiments. The scope of protection of the present disclosure should be interpreted by the claims below, and all technical ideas within a scope equivalent thereto should be interpreted as being included within the scope of the rights of the present disclosure.

[0359]

[0360] CROSS-REFERENCE TO RELATED APPLICATION

[0361] This patent application claims priority under 35 USC §119(a) to Korean Patent Application No. 10-2024-0020501, filed in Korea on February 13, 2024, Korean Patent Application No. 10-2024-0020516, filed in Korea on February 13, 2024, Korean Patent Application No. 10-2024-0021690, filed in Korea on February 15, 2024, and Korean Patent Application No. 10-2025-0018329, filed in Korea on February 12, 2025, the entire contents of which are incorporated herein by reference. In addition, this patent application claims priority for the same reasons as above in countries other than the United States, the entire contents of which are incorporated by reference into this patent application.

Claims

1. In a method for a terminal to receive a synchronization signal, A step of receiving change information on the transmission cycle or transmission pattern of a synchronization signal from a base station; A step of monitoring the synchronization signal based on the above change information; and A method comprising a step of receiving downlink data or a downlink reference signal by considering a change in the transmission period or transmission pattern of the synchronization signal according to the above change information.

2. In paragraph 1, The above change information is, A method for receiving based on at least one of an RRC message, DCI (Downlink Control Information) and MAC information element.

3. In paragraph 1, The above change information is, A method for indicating both the above transmission cycle and the above transmission pattern.

4. In paragraph 1, The above synchronization signal changed according to the above change information is, How to maintain a QCL (Quasi-Colocation) relationship at the same index as the index of the synchronization signal before the change.

5. In paragraph 1, The above downlink data is, A method of assigning unallocated or duplicate transmission resources to the transmission resources of the synchronization signal before the change.

6. In paragraph 1, When transmitting channel status information feedback using the above synchronization signal as the above downlink reference signal, A method in which periodic feedback on the above channel status information feedback is limited or the configuration information applied to the synchronization signal before the change is disabled.

7. In the method of transmitting a synchronization signal by a base station, A step of transmitting change information about the transmission cycle or transmission pattern of a synchronization signal to a terminal; and A method comprising a step of determining a transmission resource of the synchronization signal or downlink data based on the change information.

8. In paragraph 7, The above change information is, A method for transmitting based on at least one of an RRC message, DCI (Downlink Control Information) and MAC information element.

9. In paragraph 7, The above change information is, A method for indicating both the above transmission cycle and the above transmission pattern.

10. In paragraph 7, The above synchronization signal changed according to the above change information is, How to maintain a QCL (Quasi-Colocation) relationship at the same index as the index of the synchronization signal before the change.

11. In paragraph 7, The above downlink data is, A method of assigning unallocated or duplicate transmission resources to the transmission resources of the synchronization signal before the change.

12. In a terminal receiving a synchronization signal, A receiving unit that receives change information on the transmission cycle or transmission pattern of a synchronization signal from a base station; and Including a control unit that monitors the synchronization signal based on the above change information, The above receiver, A terminal that receives downlink data or a downlink reference signal by considering a change in the transmission period or transmission pattern of the synchronization signal according to the above change information.

13. In paragraph 12, The above change information is, A terminal receiving based on at least one of an RRC message, DCI (Downlink Control Information), and MAC information element.

14. In paragraph 12, The above change information is, A terminal that indicates both the above transmission cycle and the above transmission pattern.

15. In paragraph 12, The above synchronization signal changed according to the above change information is, A terminal that maintains a QCL (Quasi-Colocation) relationship at the same index as the index of the synchronization signal before the change.

16. In paragraph 12, The above downlink data is, A terminal that is not allocated to the transmission resources of the synchronization signal before the change or is allocated for duplicate transmission.

17. In paragraph 12, When transmitting channel status information feedback using the above synchronization signal as the above downlink reference signal, A terminal in which periodic feedback on the above channel status information feedback is limited or in which the configuration information applied to the synchronization signal before change is deactivated.

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