Method for measuring downlink signal and apparatus therefor

Abstract

A method for measuring channel state information (CSI) by a terminal in a wireless communication system is disclosed. In particular, the method comprises: receiving first information related to a first transmission power of a CSI-reference signal (CSI-RS); the CSI-RS is received; and starting measurement of the first CSI on the basis of the first transmission power and the CSI-RS, in which second CSI is measured on the basis of the CSI-RS and a second transmission power on the basis of receiving second information related to the second transmission power of the CSI-RS having a value different from the first transmission power.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for measuring a downlink (DL) signal, and more particularly, to a method and apparatus for measuring a DL signal when transmission power of the DL signal is dynamically changed. Background Art

[0002] As more and more communication devices require greater communication services in line with the current trend, the next-generation fifth-generation (5G) system is needed to provide enhanced wireless broadband communication compared to the traditional LTE system. In the next-generation 5G system, communication scenarios are divided into enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), massive machine type communication (mMTC), etc.

[0003] In this article, eMBB is a next-generation mobile communication scenario characterized by high spectral efficiency, high user experience data rate, and high peak data rate, URLLC is a next-generation mobile communication scenario characterized by ultra-high reliability, ultra-low latency, and ultra-high availability (e.g., vehicle-to-everything (V2X), emergency services, and remote control), and mMTC is a next-generation mobile communication scenario characterized by low cost, low energy, short packets, and massive connections (e.g., the Internet of Things (IoT)). Summary of the invention

[0004] Technical issues

[0005] An object of the present disclosure is to provide a method and apparatus for measuring a downlink signal.

[0006] Those skilled in the art will appreciate that the objectives that can be achieved by the present disclosure are not limited to what has been specifically described above, and the above and other objectives that can be achieved by the present disclosure will be more clearly understood from the following detailed description.

[0007] Technical Solution

[0008] According to an embodiment of the present disclosure, a method for measuring channel state information (CSI) by a user equipment (UE) in a wireless communication system may include: receiving first information related to a first transmission power of a channel state information-reference signal (CSI-RS); receiving the CSI-RS; and starting measurement of the first CSI based on the first transmission power and the CSI-RS. Based on receiving second information related to a second transmission power of the CSI-RS having a value different from the first transmission power, a second CSI may be measured based on the CSI-RS and the second transmission power.

[0009] The measurement of the first CSI may be ignored based on the measurement of the second CSI.

[0010] Furthermore, the second CSI may be measured based on a weighting factor corresponding to the second transmission power.

[0011] Furthermore, the second CSI may be transmitted together with a timestamp for a point in time when measurement of the second CSI starts.

[0012] Furthermore, the second information may be applied at a point in time before the measurement of the first CSI is completed.

[0013] Furthermore, the second transmission power may be determined based on the first transmission power and the number of antenna ports turned on by a base station (BS).

[0014] A UE for measuring CSI in a wireless communication system according to the present disclosure may include: at least one transceiver; at least one processor; and at least one memory, the at least one memory being operably connected to the at least one processor and storing instructions, which, when executed, cause the at least one processor to perform operations. The operations may include: receiving first information related to a first transmission power of a CSI-RS through at least one transceiver; receiving a CSI-RS through at least one transceiver; and starting measurement of a first CSI based on the first transmission power and the CSI-RS. Based on receiving second information related to a second transmission power of the CSI-RS having a value different from the first transmission power, a second CSI may be measured based on the CSI-RS and the second transmission power.

[0015] The measurement of the first CSI may be ignored based on the measurement of the second CSI.

[0016] Furthermore, the second CSI may be measured based on a weighting factor corresponding to the second transmission power.

[0017] In addition, the second CSI may be transmitted together with a timestamp of a time point at which measurement of the second CSI starts.

[0018] Furthermore, the second information may be applied at a point in time before the measurement of the first CSI is completed.

[0019] Furthermore, the second transmission power may be determined based on the first transmission power and the number of antenna ports turned on by the BS.

[0020] According to the present disclosure, a device for measuring CSI in a wireless communication system may include: at least one processor; and at least one memory, the at least one memory being operably connected to the at least one processor and storing instructions, which, when executed, cause the at least one processor to perform operations. The operations may include: receiving first information related to a first transmission power of a CSI-RS; receiving a CSI-RS; and starting measurement of a first CSI based on the first transmission power and the CSI-RS. Based on receiving second information related to a second transmission power of the CSI-RS having a value different from the first transmission power, a second CSI may be measured based on the CSI-RS and the second transmission power.

[0021] A computer-readable storage medium according to the present disclosure may include at least one computer program, and the at least one computer program causes at least one processor to perform operations. The operations may include: receiving first information related to a first transmission power of a CSI-RS; receiving a CSI-RS; and starting measurement of a first CSI based on the first transmission power and the CSI-RS. Based on receiving second information related to a second transmission power of the CSI-RS having a value different from the first transmission power, a second CSI may be measured based on the CSI-RS and the second transmission power.

[0022] According to an embodiment of the present disclosure, a method for receiving CSI by a BS in a wireless communication system may include: transmitting first information related to a first transmission power of a CSI-RS; transmitting a CSI-RS; transmitting second information related to a second transmission power of the CSI-RS having a value different from the first transmission power; and receiving CSI based on the CSI-RS. The CSI may include measurement information based on the CSI-RS and the second transmission power.

[0023] A BS for receiving CSI in a wireless communication system according to the present disclosure may include: at least one transceiver; at least one processor; and at least one memory, the at least one memory being operably connected to the at least one processor and storing instructions, the instructions causing the at least one processor to perform operations when executed. The operations may include: sending first information related to a first transmission power of a CSI-RS through at least one transceiver; sending a CSI-RS through at least one transceiver; sending second information related to a second transmission power of the CSI-RS having a value different from the first transmission power through at least one transceiver; and receiving CSI based on the CSI-RS through at least one transceiver. The CSI may include measurement information based on the CSI-RS and the second transmission power.

[0024] Beneficial Effects

[0025] According to the present disclosure, the power consumption of a base station (BS) can be reduced by providing the following mechanism: the BS dynamically changes the transmission power of a synchronization signal block (SSB) and / or a channel state information-reference signal (CSI-RS) and / or a physical downlink shared channel (PDSCH) while considering the communication status with a related user equipment (UE), the amount of data, etc.

[0026] Those skilled in the art will recognize that the effects that can be achieved using the present disclosure are not limited to the contents that have been specifically described above, and other advantages of the present disclosure will be more clearly understood from the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Diagram illustrating network energy savings.

[0028] Figure 2 is a diagram illustrating analog beamforming in an NR system.

[0029] Figure 3 An exemplary multi-beam transmission of a synchronization signal block (SSB) is illustrated.

[0030] Figures 4 to 8 is a diagram illustrating beam management in an NR system.

[0031] Figures 9 to 11 is a diagram of an overall operation process of a user equipment (UE) and a base station (BS) according to an embodiment of the present disclosure.

[0032] Fig.12 is a diagram illustrating an example of mapping an antenna port to each CSI-RS resource according to an embodiment of the present disclosure.

[0033] Fig.13 An exemplary communication system to which the present disclosure is applied is illustrated.

[0034] Fig.14 An exemplary wireless device suitable for use with the present disclosure is shown.

[0035] Fig.15 An exemplary vehicle or autonomous vehicle suitable for use with the present disclosure is shown. DETAILED DESCRIPTION

[0036] The following technology can be used in various wireless access systems, such as code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), etc. CDMA can be implemented as a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented as a radio technology such as Global System for Mobile Communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA can be implemented as a radio technology such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wireless Fidelity (Wi-Fi)), IEEE 802.16 (Worldwide Interoperability for Microwave Access (WiMAX)), IEEE 802.20, Evolved UTRA (E-UTRA), etc. UTRA is part of Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a part of Evolved UMTS (E-UMTS) using E-UTRA, and LTE Advanced (LTE-A) is an evolution of 3GPP LTE. 3GPP New Radio or New Radio Access Technology (NR) is an evolved version of 3GPP LTE / LTE-A.

[0037] Although the following description is given in the context of a 3GPP communication system (e.g., NR) for clarity, the technical spirit of the present disclosure is not limited to the 3GPP communication system. For background technology, the terms and abbreviations used in the present disclosure refer to technical specifications (e.g., 38.211, 38.212, 38.213, 38.214, 38.300, 38.331, etc.) published before the present disclosure.

[0038] 5G communication involving a new radio access technology (NR) system will be described below.

[0039] The three key requirement areas for 5G are (1) enhanced mobile broadband (eMBB), (2) massive machine-type communications (mMTC), and (3) ultra-reliable and low-latency communications (URLLC).

[0040] Some use cases may require optimization in multiple dimensions, while others may focus on just one key performance indicator (KPI). 5G supports this variety of use cases in a flexible and reliable manner.

[0041] eMBB goes far beyond basic mobile Internet access and covers rich interactive work, media and entertainment applications in the cloud or augmented reality (AR). Data is one of the key drivers of 5G, and in the 5G era, we may see no dedicated voice services for the first time. In 5G, it is expected that voice is simply processed as an application using the data connection provided by the communication system. The main driving force for the increased traffic is the increase in content size and the number of applications that require high data rates. As more devices are connected to the Internet, streaming services (audio and video), interactive video, and mobile Internet connections will continue to be more widely used. Many of these applications require always-on connections to push real-time information and notifications to users. For mobile communication platforms, cloud storage and applications are increasing rapidly. This applies to both work and entertainment. Cloud storage is a specific use case that drives the growth of uplink data rates. 5G will also be used for remote work in the cloud, which requires much lower end-to-end latency when done using a tactile interface in order to maintain a good user experience. Entertainment (e.g., cloud gaming and video streaming) is another key driver for increased demand for mobile broadband capacity. Entertainment is very important on smartphones and tablets anywhere, including high mobility environments such as trains, cars and airplanes. Another use case is AR and information search for entertainment, which requires very low latency and large amounts of real-time data.

[0042] One of the most anticipated 5G use cases is the ability to actively connect embedded sensors in every field, i.e. mMTC. It is expected that there will be 20.4 billion potential Internet of Things (IoT) devices by 2020. In industrial IoT, 5G is one of the areas that will play a key role in enabling smart cities, asset tracking, smart utilities, agriculture, and secure infrastructure.

[0043] URLLC includes services that will transform industries utilizing ultra-reliable / available low-latency links, such as remote control of critical infrastructure and autonomous vehicles. Reliability and latency levels are critical for smart grid control, industrial automation, robotics, drone control and coordination, etc.

[0044] Now, multiple use cases in a 5G communication system including an NR system will be described in detail.

[0045] 5G can complement fiber-to-the-home (FTTH) and cable-based broadband (or cable data service interface specification (DOCSIS)) as a means of delivering streams at data rates ranging from hundreds of megabits per second to gigabits per second. Such high speeds are needed for television broadcasts with resolutions of 4K (6K, 8K, and higher) or higher, as well as virtual reality (VR) and AR. VR and AR applications mainly include immersive sports games. Specific applications may require special network configurations. For example, for VR games, gaming companies may have to integrate core servers with network operators' edge network servers in order to minimize latency.

[0046] The automotive industry is expected to become a very important new driver for 5G, where many use cases are used for mobile communications in vehicles. For example, the entertainment of passengers requires mobile broadband with both high capacity and high mobility, as future users will expect to continue their good quality connection independently of their location and speed. Other use cases in the automotive industry are AR dashboards. These displays overlay information on what the driver sees through the front window, identifying objects in the dark and telling the driver the distance and movement of objects. In the future, wireless modules will enable communication between the vehicles themselves, between the vehicle and the supporting infrastructure, and between the vehicle and other connected devices (e.g., those carried by pedestrians). Safety systems can guide drivers in alternative courses of action to allow them to drive more safely and reduce the risk of accidents. The next stage will be remote-controlled or autonomous vehicles. These require very reliable, very fast communication between different autonomous vehicles and between vehicles and infrastructure. In the future, autonomous vehicles will perform all driving activities, while the driver focuses on the elusive traffic anomalies in the vehicle itself. The technical needs of autonomous vehicles require ultra-low latency and ultra-high reliability, raising traffic safety to a level that people cannot achieve.

[0047] Smart cities and smart homes (often referred to as smart societies) will be embedded with dense wireless sensor networks. Distributed networks of smart sensors will identify conditions for cost and energy-saving maintenance in a city or home. A similar setup can be done for each home, where temperature sensors, window and heating controls, burglar alarms, and home appliances are all wirelessly connected. Many of these sensors are typically characterized by low data rates, low power, and low cost, but for example, real-time high-definition (HD) video may be required for monitoring in certain types of equipment.

[0048] The consumption and distribution of energy (including heat or gas) is becoming highly decentralized, creating a need for automatic control of very distributed sensor networks. Smart grids interconnect these sensors, using digital information and communication technologies to collect and act on information. This information can include information about the behavior of suppliers and consumers, allowing smart grids to improve the efficiency, reliability, economy and sustainability of the production and distribution of fuels such as electricity in an automated manner. Smart grids can be viewed as another sensor network with low latency.

[0049] The health sector has many applications that can benefit from mobile communications. Communication systems enable telemedicine that provides remote clinical health care. It helps eliminate distance barriers and can improve access to medical services that are not always available in remote rural communities. It is also used to save lives in critical care and emergency situations. Wireless sensor networks based on mobile communications can provide remote monitoring and sensors for parameters such as heart rate and blood pressure.

[0050] Wireless and mobile communications are becoming increasingly important for industrial applications. Wires are expensive to install and maintain, and the possibility of replacing them with reconfigurable wireless links is an attractive opportunity for many industries. However, achieving this requires wireless connections to work with similar latency, reliability, and capacity as cables, and to simplify their management. Low latency and very low probability of error are new requirements that need to be addressed with 5G.

[0051] Finally, logistics and freight tracking are important use cases for mobile communications, which enable tracking of inventory and packages anytime, anywhere by using location-based information systems. Logistics and freight tracking use cases typically require lower data rates but require wide coverage and reliable location information.

[0052] Figure 1 is a diagram illustrating network energy saving (NES) according to the present disclosure.

[0053] It has been reported that the New RAT (NR) base station (BS) consumes 3 to 4 times the power of the Long Term Evolution (LTE) BS due to the higher installed BS density and the use of more antennas / bandwidths / frequency bands compared to the NR system and LTE system. In order to solve the problem of increased operator operating costs caused by this and build an environmentally friendly network, a research project was approved to discuss methods for reducing BS energy consumption.

[0054] In 3GPP RAN WG1, an energy consumption model and simulation method for BS are defined to show that energy consumption benefits can be obtained by applying NES technology. Specifically, a sleep state (i.e., a state in which the base station does not perform transmission and reception) and an active state (i.e., a state in which the base station performs transmission and / or reception) are defined for the base station, and a transition method for each state is determined, such as Figure 1 In addition, the relative power consumed by the BS in each state, the time and energy required for state transition, etc. are modeled.

[0055] The technologies discussed for NES in 3GPP RAN WG1 can be roughly classified into four domains (ie, time / frequency / space / power domains), and the specific technologies of each domain can be summarized as in [Table 1].

[0056] [Table 1]

[0057]

[0058]

[0059] As time domain NES technology, methods such as controlling the on / off of UE common signals (e.g., SSB, SIB, paging, etc.) or UE specific signals (e.g., CSI-RS) (such as A-1, A-2 and / or A-5 in Table 1), sending a wake-up signal to wake up an inactive BS (such as A-3 in Table 1), or controlling the transmission and reception of the UE according to the discontinuous transmission / discontinuous reception (DTX / DRX) pattern of the BS (e.g., A-4 in Table 1) have been discussed.

[0060] As frequency domain NES technologies, methods such as SCell operating without a synchronization signal block (SSB) in an inter-band CA scenario (such as B-1 in Table 1) and switching bandwidth parts (BWP) or controlling the bandwidth of BWP (such as B-2 and / or B-3 in Table 1) have been discussed.

[0061] As a spatial domain NES technology, methods such as C-1 and / or C-2 in Table 1 that support turning on / off each antenna port in a BS or turning on / off each transmission and reception point (TRP) and improving associated CSI measurement and reporting have been discussed.

[0062] As power domain NES technologies, methods such as increasing transmission efficiency by dynamically changing the power of downlink (DL) signals (e.g., SSB, CSI-RS, and PDSCH) (such as D-1 in Table 1) or maximizing power amplifier (PA) efficiency by applying digital distortion compensation or tone reservation for BS / UE (such as D-2, D-3, D-4, and / or D-5 in Table 1) have been discussed.

[0063] In addition to the technologies jointly discussed in 3GPP RAN WG1 and 3GPP RAN WG2 (for example, A-4, A-5 and B-1), the technologies for NES discussed in 3GPP RAN WG2 include a method for accessing an NES cell by a UE with NES capability or an existing NR UE, an efficient switching method for UE connected to an NES cell, and the like.

[0064] As a result of the RAN#98-e meeting, the NES work items were approved, and the discussion topics in each leading WG are as follows. RAN WG1-led items include methods for supporting turning on / off BS antenna ports or dynamically changing the power offset between the physical downlink shared channel (PDSCH) and the channel state information reference signal (CSI-RS) (e.g., C-1 and D-1), and enhancing CSI measurement and reporting. RAN WG2-led items include methods for controlling the transmission and reception of UEs according to the DTX / DRX pattern of the BS (e.g., A-4), methods for preventing existing NR UEs from accessing NES cells, and conditional switching (CHO) methods considering source or target cells performing NES operations. In addition, RAN WG3-led items include methods for exchanging information about active beams between nodes and methods for paging over a limited area. RAN WG4-led items include SCells operating without SSB in inter-band CA scenarios (e.g., B-1).

[0065] In the NR system, a large-scale multiple-input multiple-output (MIMO) environment in which the number of transmission / reception (Tx / Rx) antennas is significantly increased can be considered. That is, when considering a large-scale MIMO environment, the number of Tx / Rx antennas can be increased to tens or hundreds. The NR system supports communications in frequency bands above 6 GHz (i.e., millimeter bands). However, the millimeter band is characterized by a frequency characteristic in which the signal decays very quickly according to the distance due to the use of too high a frequency band. Therefore, in an NR system operating at 6 GHz or above, beamforming (BF) is considered, in which a signal is sent in a specific direction rather than omnidirectionally with concentrated energy to compensate for rapid propagation attenuation. Therefore, for the purpose of improving performance, flexible resource allocation, and ease of frequency beam control in a large-scale MIMO environment, a hybrid BF with a combination of analog BF and digital BF according to the position of the applied BF weight vector / precoding vector is required.

[0066] Figure 2 is a block diagram illustrating an exemplary transmitter and receiver for hybrid BF.

[0067] In order to form a narrow beam in the millimeter frequency band, the BF method is mainly considered, in which the BS or UE sends the same signal through multiple antennas by applying an appropriate phase difference to the antenna and thus increasing energy only in a specific direction. This BF method includes a digital BF for generating a phase difference for a digital baseband signal, an analog BF for generating a phase difference by using a time delay (ie, a cyclic shift) to modulate an analog signal, and a hybrid BF with a combined digital BF and analog beamforming. Using a radio frequency (RF) unit (or transceiver unit (TXRU)) for antenna elements to control transmission power and phase control based on antenna elements enables independent BF to be implemented for each frequency resource. However, installing TXRU in all approximately 100 antenna elements is not feasible in terms of cost. That is, a large number of antennas are required to compensate for the rapid propagation attenuation in millimeter frequencies, and digital BF requires as many RF components (e.g., digital-to-analog converters (DACs), mixers, power amplifiers, and linear amplifiers) as the number of antennas. Therefore, implementing digital BF in millimeter frequency bands increases the price of communication equipment. Therefore, when a large number of antennas are required, as in the case of millimeter frequency bands, consider analog BF or hybrid BF. In analog BF, multiple antenna elements are mapped to a single TXRU and the beam direction is controlled by analog phase shifters. Because only one beam direction is generated over the entire frequency band in analog BF, frequency selective BF may not be achieved using analog BF. Hybrid BF is an intermediate form between digital BF and analog BF, using B RF units with less than Q antenna elements. In hybrid BF, the number of beam directions available for simultaneous transmission is limited to B or less, depending on how the B RF units and Q antenna elements are connected.

[0068] Beam Alignment

[0069] Figure 3 An exemplary multi-beam transmission of SSB is illustrated.

[0070] Beam scanning refers to changing the beam (direction) of a wireless signal over time at a transmit receive point (TRP) (eg, BS / cell) (hereinafter, the terms beam and beam direction are used interchangeably). Fig.10 , SSBs can be sent periodically by beam scanning. In this case, the SSB index is implicitly linked to the SSB beam. The SSB beam can be changed on an SSB (index) basis or on an SS (index) group basis. In the latter case, the same SSB beam is maintained in the SSB (index) group. That is, the transmission beam direction of the SSB is repeated for multiple consecutive SSBs. Depending on the frequency band of the carrier, the maximum allowed transmission number L of SSBs in the SSB beam set is 4, 8, or 64. Therefore, the maximum number of SSB beams in the SSB beam set can be given according to the frequency band of the carrier as follows.

[0071] - For frequency range up to 3 GHz, maximum number of beams = 4

[0072] - For the frequency range from 3 GHz to 6 GHz, maximum number of beams = 8

[0073] - For the frequency range from 6 GHz to 52.6 GHz, maximum number of beams = 64

[0074] *In the absence of multi-beam transmission, the number of SSB beams is 1.

[0075] When a UE attempts to initially access a BS, the UE may align the beam with the BS based on the SSB. For example, the UE performs SSB detection and then identifies the best SSB. Subsequently, the UE may send a RACH preamble in a PRACH resource linked / corresponding to the index (i.e., beam) of the best SSB. Even after initial access, the SSB may be used for beam alignment between the BS and the UE.

[0076] Beam Management (BM)

[0077] BM refers to a series of processes for acquiring and maintaining a set of BS beams (transmission and reception point (TRP) beams) and / or a set of UE beams that can be used for DL ​​and UL transmission / reception. BM may include the following processes and terms.

[0078] - Beamforming: An operation where a BS or UE measures the characteristics of a received beamforming signal

[0079] -Beam determination: The operation by which the BS or UE selects its Tx / Rx beam

[0080] -Beam scanning: Operation that covers the spatial domain by using Tx and / or Rx beams at prescribed time intervals according to a predetermined method

[0081] - Beam reporting: Operation of UE to report information about beamformed signals based on beam measurements

[0082] The BM process may be divided into (1) a DL BM process using SSB or CSI-RS and (2) a UL BM process using SRS. In addition, each BM process may include Tx beam scanning for determining a Tx beam and Rx beam scanning for determining an Rx beam.

[0083] The DL BM process may include (1) transmission of a beamformed DL RS (eg, CSI-RS or SSB) from a BS and (2) beam reporting from a UE.

[0084] The beam report may include (one or more) preferred DL RS IDs and (one or more) reference signal received powers (RSRPs) corresponding to (one or more) preferred DL RS IDs. The DL RS ID may be a SSB resource indicator (SSBRI) or a CSI-RS resource indicator (CRI).

[0085] Figure 4 is a diagram illustrating an exemplary BF using SSB and CSI-RS.

[0086] refer to Figure 4 , SSB beam and CSI-RS beam can be used for beam measurement. The measurement metric is RSRP per resource / block. SSB can be used for coarse beam measurement, while CSI-RS can be used for fine beam measurement. SSB can be used for both Tx beam scanning and Rx beam scanning. SSB-based Rx beam scanning can be performed by attempting to receive SSBs for the same SSBRI while changing the Rx beam across multiple SSB bursts at the UE. An SS burst includes one or more SSBs, and an SS burst set includes one or more SSB bursts.

[0087] 1. DL BM using SSB

[0088] Figure 5 is a diagram illustrating a signal flow of an exemplary DL BM process using SSB.

[0089] During CSI / beam configuration in RRC_CONNECTED mode, SSB based beam reporting is configured.

[0090] -The UE receives a CSI-ResourceConfig information element (IE) including a CSI-SSB-ResourceSetList of SSB resources for BM from the BS (S510). The RRC parameter CSI-SSB-ResourceSetList is a list of SSB resources used for BM and reported in one resource set. The SSB resource set may be configured as {SSBx1, SSBx2, SSBx3, SSBx4}. The SSB index may range from 0 to 63.

[0091] -The UE receives a signal in SSB resources from the BS based on the CSI-SSB-ResourceSetList (S520).

[0092] -When CSI-RS reportConfig related to SSBRI and RSRP reporting has been configured, the UE reports the best SSBRI and the RSRP corresponding to the best SSBRI to the BS (S530). For example, when reportQuantity in the CSI-RS reportConfig IE is set to "ssb-Index-RSRP", the UE reports the best SSBRI and the RSRP corresponding to the best SSBRI to the BS.

[0093] When CSI-RS resources are configured in (one or more) OFDM symbols carrying SSBs and "QCL-TypeD" is applicable to CSI-RS resources and SSBs, the UE may assume that CSI-RS and SSBs are quasi co-located (QCLed) from the perspective of "QCL-TypeD". QCL-TypeD may refer to a QCL antenna port from the perspective of spatial Rx parameters. When a UE receives signals from multiple DL antenna ports in a QCL-TypeD relationship, the UE may apply the same Rx beam to the signals.

[0094] 2. DL BM using CSI-RS

[0095] CSI-RS is used for the following purposes: i) when Repetition is configured for a specific CSI-RS resource set and TRS_info is not configured, CSI-RS is used for BM; ii) when Repetition is not configured for a specific CSI-RS resource set and TRS_info is configured, CSI-RS is used for tracking reference signal (TRS); and iii) when either Repetition or TRS_info is configured for a specific CSI-RS resource set, CSI-RS is used for CSI acquisition.

[0096] When (RRC parameter) Repetition is set to "on", this is related to the Rx beam scanning process of the UE. When Repetition is set to "on", when the UE is configured with NZP-CSI-RS-ResourceSet, the UE can assume that the signal in at least one CSI-RS resource in the NZP-CSI-RS-ResourceSet is sent through the same DL spatial domain filter. That is, at least one CSI-RS resource within the NZP-CSI-RS-ResourceSet is sent on the same Tx beam. The signal in at least one CSI-RS resource within the NZP-CSI-RS-ResourceSet can be sent in different OFDM symbols.

[0097] On the contrary, when Repetition is set to "off", this is related to the Tx beam scanning process of the BS. When Repetition is set to "off", the UE does not assume that the signal in at least one CSI-RS resource within the NZP-CSI-RS-ResourceSet is sent through the same DL spatial domain filter. That is, the signal in at least one CSI-RS resource within the NZP-CSI-RS-ResourceSet is sent on different Tx beams. Fig.12 Another exemplary DL BM procedure using CSI-RS is illustrated.

[0098] Figure 6 (a) illustrates the UE’s Rx beam refinement process, and Figure 6 (b) illustrates the BS’s Tx beam scanning process. Figure 6 (a) is used when Repetition is set to "On", and Figure 5 (b) For when Repetition is set to “off”.

[0099] refer to Figure 6 (a) and Figure 7 (a), the Rx beam determination process of the UE will be described below.

[0100] Figure 7 (a) is a diagram illustrating a signal flow of an exemplary Rx beam determination process for a UE.

[0101] - The UE receives the NZP CSI-RS resource set IE including the RRC parameter "Repetition" from the BS through RRC signaling (S710). Herein, the RRC parameter "Repetition" is set to "ON".

[0102] - The UE repeatedly receives signals in (one or more) resources of a CSI-RS resource set in which the RRC parameter “Repetition” is set to “ON” on the same Tx beam (or DL ​​spatial domain Tx filter) of the BS in different OFDM symbols (S720).

[0103] -UE determines its Rx beam (S730).

[0104] -UE skips CSI reporting (S740). That is, when the RRC parameter "Repetition" is set to "ON", the UE may skip CSI reporting.

[0105] refer to Figure 6 (b) and Figure 7 (b), the Tx beam determination process of the BS will be described below.

[0106] Figure 7 (b) is a diagram illustrating an exemplary Tx beam determination process of a BS.

[0107] - The UE receives the NZP CSI-RS resource set IE including the RRC parameter "Repetition" from the BS through RRC signaling (S750). When the RRC parameter "Repetition" is set to "off", this is related to the Tx beam scanning process of the BS.

[0108] - The UE receives a signal in (one or more) resources of a CSI-RS resource set in which the RRC parameter “Repetition” is set to “off” on different Tx beams (or DL ​​spatial domain Tx filters) of the BS (S760).

[0109] - The UE selects (or determines) the best beam (S770).

[0110] - The UE reports the ID (eg, CRI) of the selected beam and related quality information (eg, RSRP) to the BS (S780). That is, when the CSI-RS is transmitted for the BM, the UE reports the CRI and the RSRP corresponding to the CRI.

[0111] Figure 8 It is a graphic with Figure 6 FIG. 5 is a diagram of exemplary resource allocation in the time domain and the frequency domain associated with the operation of FIG.

[0112] When Repetition is set to "On" for a CSI-RS resource set, multiple CSI-RS resources can be repeatedly used on the same Tx beam, and when Repetition is set to "Off" for a CSI-RS resource set, different CSI-RS resources can be repeatedly sent on different Tx beams.

[0113] 3.DL BM related beam indication

[0114] The UE may receive a list of at least up to M candidate transmission configuration indication (TCI) states for QCL indication via RRC signaling. M depends on the UE capability and may be 64.

[0115] Each TCI state may be configured with one RS set. Table 2 describes an example of TC-State IE. TC-State IE is related to the QCL type corresponding to one or two DL RSs.

[0116] [Table 2]

[0117]

[0118] In Table 2, "bwp-Id" identifies the DL BWP where the RS is located, "cell" indicates the carrier where the RS is located, and "referencesignal" indicates the reference antenna port(s) used as the QCL source for the target antenna port(s) or the RS including the reference antenna port(s). The target antenna port(s) may be used for CSI-RS, PDCCH DMRS, or PDSCH DMRS.

[0119] 4. Quasi-co-location (QCL)

[0120] A UE may receive a list of up to M TCI state configurations to decode the PDSCH based on a detected PDCCH carrying DCI intended for a given cell. M depends on the UE capabilities.

[0121] Each TCI-State includes parameters for establishing a QCL relationship between one or more DL RSs and PDSCH DM-RS ports as described in Table 2. The QCL relationship is established using RRC parameters qcl-Type1 for the first DL RS and qcl-Type2 for the second DL RS (if configured).

[0122] The QCL type of each DL RS is given by a parameter 'qcl-Type' included in QCL-Info and may have one of the following values.

[0123] - 'QCL-TypeA': {Doppler shift, Doppler spread, average delay, delay spread}

[0124] - 'QCL-TypeB': {Doppler shift, Doppler spread}

[0125] - 'QCL-TypeC': {Doppler shift, average delay}

[0126] - 'QCL-TypeD': {spatial Rx parameters}

[0127] For example, if the target antenna port is for a specific NZP CSI-RS, the NZP CSI-RS antenna port may be indicated / configured to be QCL with a specific TRS from the perspective of QCL-Type A, and to be QCL with a specific SSB from the perspective of QCL-Type D. Upon receiving this indication / configuration, the UE may receive the NZP CSI-RS using the Doppler value and delay value measured in the QCL-TypeA TRS, and apply the Rx beam for receiving the QCL-TypeD SSB to receive the NZP CSI-RS.

[0128] Energy saving of base stations is considered important in wireless communication systems including 3GPP because it may contribute to building environmentally friendly networks by reducing carbon emissions and reducing operating expenditures (OPEX) of communication industry players. In particular, because the introduction of 5G communications requires high transmission rates, base stations should be equipped with more antennas and provide services in wider bandwidths and frequency bands. As a result, according to recent studies, the energy cost of base stations has reached 20% of the total OPEX. Due to the growing interest in BS energy saving, a new research project called "Network Energy Saving Research" was approved in 3GPP NR Release 18.

[0129] Specifically, in order to improve the energy saving capability of the BS from the perspectives of transmission and reception, the following enhancement techniques are being considered.

[0130] - How to more efficiently apply one or more NES techniques in the time, frequency, space, and power domains based on UE assistance information and potential support / feedback from the UE for dynamic and / or semi-static operation and finer granularity adaptation in transmission and reception -

[0131] For the purpose of NES, the BS may implement techniques such as controlling on / off within a predetermined duration on the time axis, controlling the transmission / reception resources for UE common or UE specific signals / channels, changing the amount of frequency resources, controlling the transmission power, or turning on / off antenna ports or TRPs in the spatial domain. The state in which these techniques are applied (defined as NES_techs for convenience) may be defined as NES mode or NES state.

[0132] The BS may indicate the applied NES_tech to the UE based on NES_tech or based on the NES_tech group (hereinafter referred to as method 1), or pre-configure the NES_tech or NES_tech group corresponding to each code point of the specific indicator. The specific indicator may be indicated by DCI or a media access control control element (MAC CE) or configured by higher layer signaling (hereinafter referred to as method 2).

[0133] In method 1, when at least one NES_tech is applied, the UE may define the corresponding state as an NES mode or an NES state, or may define a different NES mode or a different NES state depending on which NES_tech is applied.

[0134] In method 2, for example, when there is a 1-bit indicator, "0" may indicate no corresponding NES_tech, and "1" may be linked to one or more NES_techs. When the 1-bit indicator indicates "1", the UE may define the corresponding state as NES mode or NES state.

[0135] In another example, when there is a 2-bit indicator, "00" may indicate no corresponding NES_tech, "01" may be linked to at least one NES_tech_A, "10" may be linked to at least one NES_tech_B, and "11" may be linked to at least one NES_tech_C. When the 2-bit indicator indicates a code point other than "00", the UE may define the corresponding state as an NES mode or an NES state.

[0136] Furthermore, when the 2-bit indicator indicates "01", it can be defined as NES state #1, when it indicates "10", it can be defined as NES state #2, and when it indicates "11", it can be defined as NES state #3. In this way, for each code point, it is possible to identify whether an NES state is indicated, or which NES state the current NES state is.

[0137] In particular, the present disclosure proposes a method for saving energy of a BS by controlling the transmission power of the BS.

[0138] The present disclosure mainly considers the scenario in which the BS obtains NES gain by dynamically controlling the transmission power of the DL signal / channel. For example, in the case where the number of UEs associated with a specific BS is small or the number of UEs to be associated with the BS is expected to be small, the BS can reduce the transmission power of the DL signal / channel such as SSB and / or non-zero power (NZP) CSI-RS to reduce the cell coverage and guide the UE to communicate with a neighboring BS or a BS operating at a different frequency, thereby saving the energy of the BS.

[0139] For example, the BS can reduce the power consumption of the BS by introducing signaling that dynamically changes the transmission power value of the BS's SSB and / or NZP CSI-RS instead of semi-static radio resource control (RRC) configuration to quickly reduce or increase the transmission power of the DL signal / channel according to the traffic volume.

[0140] Therefore, the present disclosure proposes signaling for adjusting DL transmission power of a BS and an operation of a UE receiving the same.

[0141] Figures 9 to 11 is a diagram illustrating an overall operation procedure of a UE and a BS according to the present disclosure.

[0142] Fig. 9 is a diagram illustrating an overall operation process of a UE according to the present disclosure.

[0143] refer to Fig. 9 , the UE may receive an RRC parameter for transmission power related to a DL signal (S901). For example, the RRC parameter may be a parameter related to transmission power of an SSB and / or a parameter related to transmission power of a CSI-RS.

[0144] The UE may receive downlink control information (DCI) or a medium access control element (MAC CE) for power control related to a DL signal (S903). In addition, the UE may receive a DL signal (S905). In addition, the UE may report measurement information related to the DL signal (S907).

[0145] The DL signal may be SSB and / or CSI-RS and / or PDSCH.

[0146] When the DL signal is SSB and / or CSI-RS, the above operation of the UE may be based on at least one of [Method #1] to [Method #5].

[0147] When the DL signal is PDSCH, the above operation of the UE may be based on at least one of [Method #3] or [Method #4]. For example, S901 and S903 may be skipped in this case. In addition, the measurement information in S907 may be a report related to the power of PDSCH.

[0148] Fig.10 is a diagram illustrating an overall operation procedure of a BS according to the present disclosure.

[0149] refer to Fig.10, the BS may transmit an RRC parameter for transmission power related to a DL signal (S1001). For example, the RRC parameter may be a parameter related to transmission power of an SSB and / or a parameter related to transmission power of a CSI-RS.

[0150] The BS may transmit DCI or MAC CE for power control related to the DL signal (S1003). In addition, the BS may transmit the DL signal (S1005). In addition, the BS may receive measurement information related to the DL signal (S1007).

[0151] The DL signal may be SSB and / or CSI-RS and / or PDSCH.

[0152] When the DL signal is SSB and / or CSI-RS, the above operation of the BS may be based on at least one of [Method #1] to [Method #5].

[0153] When the DL signal is PDSCH, the above operation of the BS may be based on at least one of [Method #3] or [Method #4]. For example, S1001 and S1003 may be skipped in this case. In addition, the measurement information in S1007 may be a report related to the power of PDSCH.

[0154] Fig.11 is a diagram illustrating the overall operation process of a network according to the present disclosure.

[0155] refer to Fig.11 , the BS may send an RRC parameter for transmission power related to a DL signal to the UE (S1101). For example, the RRC parameter may be a parameter related to transmission power of an SSB and / or a parameter related to transmission power of a CSI-RS.

[0156] The BS may transmit DCI or MAC CE for power control related to the DL signal to the UE (S1103). In addition, the BS may transmit the DL signal to the UE (S1005). In addition, the UE may report measurement information related to the DL signal to the BS (S1107).

[0157] The DL signal may be SSB and / or CSI-RS and / or PDSCH.

[0158] When the DL signal is SSB and / or CSI-RS, the above operation of the network may be based on at least one of [Method #1] to [Method #5].

[0159] When the DL signal is PDSCH, the above operation of the network may be based on at least one of [Method #3] or [Method #4]. For example, S1101 and S1103 may be skipped in this case. In addition, the measurement information in S1107 may be a report related to the power of PDSCH.

[0160] Meanwhile, in the following method, SSB may be interpreted as SS / PBCH block. That is, SSB and SS / PBCH block are used with the same meaning and may be interpreted as the same signal / channel.

[0161] [Method #1] Method to control SSB transmission power

[0162] Existing UEs can know the SSB transmission power of the serving BS from the parameter ss-PBCH-BlockPowerRRC. Therefore, when the BS wants to modify the SSB transmission power, it is necessary to reconfigure the RRC parameter. However, this process may involve considerable delay (e.g., tens of milliseconds). To solve this problem, a method of more dynamically indicating the SSB transmission power value for the purpose of saving BS energy may be considered.

[0163] In the method, information about the SSB transmission power value may be signaled by DCI or MAC CE. Specifically, the absolute value of the SSB transmission power (such as in ss-PBCH-BlockPower) or an offset value (e.g., -3dB, 0dB, or +3dB) from the previously signaled ss-PBCH-BlockPower may be indicated by DCI or MAC CE.

[0164] Alternatively, information about SSB transmission power may be provided indirectly by DCI or MAC CE through information of the BS such as antenna port or antenna element on / off, antenna port on / off, TRP on / off, or panel on / off. For example, when the number of antenna ports or antenna elements is reduced by half, this may mean that the SSB power value is reduced by 3dB.

[0165] Considering the processing time of the DCI or MAC CE at the UE and / or the processing time for changing the power value at the BS, there may be a question about when to apply the SSB power value sent by the signal. For this purpose, the information about the time point when the SSB power value is applied can be directly indicated by the DCI and / or MAC CE, or preconfigured or predefined. For example, it can be predefined that the changed SSB power is applied k time slots after the time slot in which the DCI and / or MAC CE is received, and the value of k can be preset.

[0166] Alternatively, for example, the changed SSB power may be defined to be applied at the first frame boundary after the reception time of the DCI and / or MAC CE, at the first SFN=0 after the reception time of the DCI and / or MAC CE, or at the start of the first system information (SI) modification period after the reception time of the DCI and / or MAC CE.

[0167] Considering a UE in an idle or inactive state, information about the SSB transmission power value and / or information about the time to apply the power value may be provided by broadcast data such as a PDCCH scheduling SI and / or a PDSCH carrying SI and / or a PDSCH including paging DCI and / or a paging message, or by a DCI scheduling the broadcast data.

[0168] In the above method, DCI or MAC CE for providing information about SSB transmission power value and / or information about the time of applying power value can be sent UE-specifically, UE group-commonly or cell-specifically. In the case of DCI, it can be sent by scrambling with RNTI configured UE-specifically, UE group-commonly or cell-specifically. In the case of MAC CE, it can be sent through PDSCH scheduled by DCI scrambled with RNTI configured UE-specifically, UE group-commonly or cell-specifically. In addition, PDSCH can also be scrambled with RNTI configured UE-specifically, UE group-commonly or cell-specifically.

[0169] The carrier / service cell carrying the DCI or MAC CE may be different from the carrier / service cell to which the information about the SSB transmission power value is applied, and the information about the SSB transmission power values ​​for multiple carriers / service cells may be provided by the DCI or MAC CE. For example, information about a common SSB transmission power value may be provided for multiple carriers / service cells, or information about different SSB transmission power values ​​may be provided for each carrier / service cell.

[0170] The above-mentioned DCI may be DCI transmitted through a group common (GC) PDCCH.

[0171] [Table 3]

[0172]

[0173]

[0174]

[0175]

[0176]

[0177]

[0178]

[0179]

[0180]

[0181]

[0182]

[0183]

[0184]

[0185]

[0186]

[0187]

[0188] Table 3 is an excerpt from 3GPP TS 38.213v17.1.0. As illustrated in Table 3, in order to measure the DL path loss value, the UE may need the SSB transmission power value and the RSRP (particularly SS-RSRP) value that has been filtered by Layer 3 (L3). For example, when the referenceSignalPower value can be determined based on the ss-PBCH-BlockPower value, if the absolute value of the SSB transmission power, the offset value from the previously signaled ss-PBCH-BlockPower, or information about the SSB transmission power value can be provided by signaling such as (group common) DCI or MAC CE as in the proposed method, the UE can update the new ss-PBCH-BlockPower value based on the power value or the offset value, and also update the referenceSignalPower value and the DL path loss value based on the updated value. The above-mentioned DCI can be a DCI sent via GC PDCCH.

[0189] The UE may perform synchronization signal (SS)-RSRP and / or SS-reference signal received quality (RSRQ) and / or SS-signal to interference plus noise ratio (SINR) measurements to calculate a DL path loss value. The measurements may correspond to L3 measurements and / or L1 measurements.

[0190] In this case, the value measured before the ss-PBCH-BlockPower changes may not be used and the measurement may be restarted, or the L3 filter coefficient may be adjusted from the time the ss-PBCH-BlockPower changes, or the filter coefficient may be set for a time point before / after the time the ss-PBCH-BlockPower changes, and the corresponding RRM may be performed.

[0191] Alternatively, information related to a timestamp of the time at which the UE performed the measurement or started filtering for the measurement may be included in the measurement report.The procedure may be equally extended to RRM for one or more neighboring cells and to RRM for the serving cell.

[0192] For one or more neighboring cells, information about the absolute value of the SSB transmission power, an offset value from the previously signaled ss-PBCH-BlockPower, or information about the SSB transmission power value may be provided through signaling such as (group common) DCI or MAC CE as in the proposed method. For example, when the information about the power value or offset value is indicated by SI, the SI change may be notified through an SI modification message of paging.

[0193] According to the 3GPP TS 38.213 specification, when performing RLM and / or link recovery procedures or beam failure detection (BFD), the UE can determine whether the link quality is above or below a specific threshold based on the configured / defined DL signal. For example, in the case of RLM, the UE can determine whether the link quality is above Q_in or below Q_out. Or in the case of BFD, the UE can determine whether the link quality is above Q_in,LR or below Q_out,LR.

[0194] The UE may eventually declare a radio link failure or a beam failure based on how many times the event has occurred (ie, the counter value for the event) during a given time period (ie, the timer period).

[0195] When an absolute value of the SSB transmission power or an offset value from the previously signaled ss-PBCH-BlockPower or information about the SSB transmission power value is provided by signaling such as (group common) DCI or MAC CE to dynamically change the ss-PBCH-BlockPower value as in the proposed method, the threshold and / or timer value and / or counter value in the RLM / BFD process can also be adjusted (by prior agreement) based on the change of the ss-PBCH-BlockPower value. For example, when the offset from the ss-PBCH-BlockPower value is signaled to the UE as 3 dB, the UE can increase the threshold such as Q_in or Q_out or Q_in,LR or Q_out,LR by 3 dB when performing SSB-based RLM or BFD.

[0196] For switching of connected UEs, a method may be considered of sending a switching threshold or an offset value of a switching offset for a specific cell for which SSB power changes to the UE to appropriately trigger events such as A1, A2, or A3 (i.e., events A1 / A2 / A3 defined in Section 5.5.4 of 3GPP TS 38.331).

[0197] When the SSB power is changed in the above method, alternative 1) the CSI-RS transmission power may also be changed as much as the change in the SSB power, or alternative 2) the CSI-RS transmission power may be changed only based on the RRC parameters.

[0198] For example, when 20dB is configured as the ss-PBCH-BlockPower value and 3dB is configured as the powerControlOffsetSS value, the UE can recognize the CSI-RS transmission power value of the BS as 23dBm. In an example of applying the above method, when +1dB is signaled as an offset from the ss-PBCH-BlockPower value through the group common DCI, the UE receiving the indication can recognize the SSB transmission power value of the BS as 21dBm, and recognize the CSI-RS transmission power value of the BS as 24dBm in alternative 1, and recognize the CSI-RS transmission power value of the BS as 23dBm in alternative 2.

[0199] [Method #1-1] Method for controlling transmission power on a per SSB index or per SSB group index basis

[0200] A method for saving the transmission power of the BS by maintaining the transmission power of a specific SSB index and controlling only the transmission power of other SSB indexes while considering coexistence with existing NR UEs may be considered. To support this, a method for controlling the transmission power on a per-SSB index or per-SSB group index basis is proposed.

[0201] As in [Method #1], the transmission power value for each SSB index or SSB group index may be indicated by a UE-specific DCI, a UE group common DCI, or a cell-specific DCI, or by a UE-specific MAC CE, a UE group common MAC CE, or a cell-specific MAC CE. When the transmission power value is indicated on a per-SSB index basis, the transmission power value for all SSB indexes or at least one SSB index included in Set_A may be indicated. For example, Set_A may include all maximum numbers of SSB indexes corresponding to frequency resources for transmitting SSBs (e.g., L_max in the 3GPP TS 38.213 specification), or may include the actual transmitted SSB (ATSS) indexes configured by the parameter ssb-PositionsInBurst.

[0202] For the transmission power value of the SSBs included in Set_A, an absolute value or an offset value of the transmission power corresponding to a specific SSB index may be indicated for each SSB index. For example, an absolute value of the transmission power for each of all SSBs included in Set_A may be indicated, or an absolute value of the transmission power for one SSB included in Set_A and an offset value for the remaining SSBs may be indicated. When the absolute value of the transmission power for a specific SSB index and the offset value for the remaining SSB indexes are indicated, the specific SSB index may be pre-determined as the lowest or highest of the SSB indexes included in Set_A, or the specific SSB index value may be pre-indicated by higher layer signaling or L1 signaling (e.g., DCI).

[0203] When the transmission power value for the SSBs included in Set_A is indicated by DCI or MAC CE, the bit position in the DCI or MAC CE for the power value corresponding to each SSB index may be preconfigured / predefined.

[0204] Similar rules may apply when indicating a transmission power value on a per SSB group index basis. Specifically, the grouping of all SSB indexes or at least one SSB index included in Set_A may be predefined or preconfigured through higher layer signaling, and the transmission power value for each SSB group index or at least one SSB group index may be indicated.

[0205] For the transmission power value, an absolute value or an offset value of the transmission power value corresponding to a specific SSB index or SSB group index may be indicated for each SSB group index. For example, an absolute value of the transmission power for each of all SSB groups included in Set_A may be indicated, or an absolute value of the transmission power for one SSB group included in Set_A or for a specific SSB included in the SSB group and an offset value for the remaining SSB groups may be indicated.

[0206] When an offset value of a transmission power value corresponding to a specific SSB group index or a specific SSB index is indicated, the specific SSB index or SSB group index may be pre-determined as the lowest or highest of the SSB indexes or SSB group indexes included in Set_A, or the specific SSB index or SSB group index may be pre-indicated through higher layer signaling.

[0207] When the transmission power value for the SSB group index included in Set_A is indicated by DCI or MAC CE, the bit position for the power value for each SSB group index in the DCI or MAC CE may be preconfigured / predefined.

[0208] In order to measure the DL path loss value as in Table 3 above, the UE may need the SSB transmission power value and the RSRP (eg, SS-RSRP) value that has been filtered through L3.

[0209] For example, when the referenceSignalPower value is determined based on the ss-PBCH-BlockPower value, if information about the transmission power value for each SSB group index or SSB index is provided through a signal such as a (group common) DCI or MAC CE as in the proposed method, the UE can update the new ss-PBCH-BlockPower value to the SSB power value of the corresponding SSB group index or SSB index based on the indicated information. In addition, the referenceSignalPower value and the DL path loss value can also be updated accordingly.

[0210] The UE may perform SS-RSRP and / or SS-RSRQ and / or SS-SINR measurements to calculate a DL path loss value. The measurements may correspond to L3 measurements and / or L1 measurements.

[0211] In this case, the value measured before the transmission power value corresponding to the SSB group index or SSB index changes may not be used, and the measurement may be restarted, or the L3 filter coefficient may be adjusted from the time when the transmission power value changes, or the filter coefficient for the time point before / after the time when the transmission power value (e.g., ss-PBCH-BlockPower) changes may be set, and the corresponding RRM may be performed. The above operation may be performed on a per SSB group index or per SSB group basis.

[0212] Alternatively, information related to a timestamp of the time at which the UE performed the measurement or started filtering for the measurement may be included in the measurement report, and this may be performed on a per SSB group index or per SSB group basis.

[0213] The process can be similarly extended to RRM for one or more neighboring cells and RRM for the serving cell. For one or more neighboring cells, information related to the transmission power value for the SSB group index or SSB index can be proposed through signaling such as (group common) DCI or MACCE as in the proposed method. For example, when the information related to the transmission power value is indicated by SI, the SI change can be notified through the SI modification message of paging, and this operation can be performed on a per SSB group index or per SSB group basis.

[0214] According to the 3GPP TS 38.213 specification, when performing RLM and / or link recovery procedures or BFD, the UE can determine whether the link quality is above or below a specific threshold based on the configured / defined DL signal. For example, in the case of RLM, the UE can determine whether the link quality is above Q_in or below Q_out. Or in the case of BFD, the UE can determine whether the link quality is above Q_in,LR or below Q_out,LR.

[0215] The UE may eventually declare a radio link failure or a beam failure based on how many times the event has occurred (ie, the counter value for the event) during a given time period (ie, the timer period).

[0216] When the transmission power value can be dynamically changed on a per-SSB group index or per-SSB index basis, the threshold and / or timer value and / or counter value in the RLM / BFD process can also be adjusted (by pre-agreement) based on the change of the power value or offset value of the corresponding SSB group index or SSB index. For example, when the transmission power value (e.g., ss-PBCH-BlockPower value) corresponding to a specific SSB group index or SSB index is signaled to the UE as 3dB, the UE can increase the threshold such as Q_in or Q_out or Q_in,LR or Q_out,LR by 3dB when performing SSB-based RLM or BFD.

[0217] For switching of connected UEs, a method may be considered of sending different switching thresholds or offset values ​​of switching offsets for specific cells for SSB power changes to the UE per SSB group index or SSB index to appropriately trigger events such as A1, A2, or A3 (i.e., events A1 / A2 / A3 defined in Section 5.5.4 of 3GPP TS 38.331).

[0218] In the random access procedure, different values ​​of the backoff indicator may be configured according to the SSB transmission power. The BS may indicate a backoff index value for a random access response (RAR) as in Table 7.2-1 of the 3GPP TS 38.321 specification, and when the UE recognizes a failure in transmitting a physical random access channel (PRACH), the UE may perform PRACH retransmission based on a backoff parameter value corresponding to the backoff index value after waiting for a specific period of time.

[0219] In addition, when different transmission powers can be configured on a per-SSB group index or per-SSB index basis, different backoff indexes can be linked or backoff parameter values ​​corresponding to the same backoff index can be configured differently according to the corresponding SSB transmission power value, SSB group index or SSB index.

[0220] For example, when multiple UEs transmit PRACH in a RACH opportunity (RO) corresponding to an SSB with a high power value, the probability of collision between the PRACHs of the UEs increases. In this regard, a rule may be predetermined or preconfigured that a larger backoff parameter value or a backoff indicator corresponding to the larger backoff parameter value is linked to an SSB group index or SSB index with a higher power value.

[0221] Alternatively, when different transmission powers can be configured on a per-SSB group index or per-SSB index basis, different scaling factor values ​​can be multiplied by the backoff parameter according to the corresponding SSB transmission power value, SSB group index, or SSB index. For example, in the case of different SSB transmission power values, SSB group indexes, or SSB indexes, different scaling factors can be configured / defined using the same backoff indicator and / or the same backoff parameter value, so that a UE that performs RACH retransmission based on the product between the scaling factor and the backoff parameter determined based on the backoff indicator performs RACH retransmission after waiting for a specific period of time.

[0222] A UE that has attempted PRACH transmission in a RO corresponding to SSB index #1 may retry PRACH transmission in a RO corresponding to a different SSB index (e.g., SSB index #2) after recognizing that the PRACH transmission has failed. Whether the UE can change the SSB index may vary depending on the power values ​​configured / indicated for SSB index #1 and SSB index #2.

[0223] For example, when the power value P2 corresponding to SSB index #2 is greater than the power value P1 corresponding to SSB index #1, the UE may be allowed to change to SSB index #2 only when the RSRP_2 value from SSB index #2 is greater than the RSRP_1 value from SSB index #1 by a specific threshold (i.e., {RSRP_2-RSRP_1}>threshold). This is done to control the probability of collision in the RO corresponding to the SSB index with a high power value, and the specific threshold may be preconfigured / predefined or calculated by the UE or BS based on the difference between P1 and P2. When the BS calculates the specific threshold, the BS may indicate the specific threshold to the UE through RRC signaling or through DCI or MAC CE.

[0224] The UE may select a specific SSB index based on the reception quality of the SSB. For example, the UE may report the SSB index having the maximum RSRP, RSRQ, or SINR value to the BS, or perform cell (re)selection based on the SSB index.

[0225] In this case, it can be considered that the transmission power is different for each SSB group index or SSB index. For example, when the power value corresponding to SSB index #1 is P1 and the power value corresponding to SSB index #2 is P2 and P1 is greater than P2, when the RSRP value measured from SSB index #1 is RSRP_1 and the RSRP value measured from SSB index #2 is RSRP_2 and {RSRP_1-RSRP_2}>threshold, the UE can determine that the reception quality of SSB index #2 is better than the reception quality of SSB index #1. The threshold can be preconfigured / predefined or calculated by the UE or BS based on the difference between P1 and P2. When the BS calculates the threshold, the BS can indicate the threshold to the UE through RRC signaling or DCI or MAC CE.

[0226] [Method #2] Method for controlling the transmission power of non-zero power (NZP) CSI-RS

[0227] Existing UEs can know the CSI-RS transmission power of each CSI-RS resource of the serving BS from the parameter powerControlOffsetSSRRC. Therefore, when the BS wants to modify the CSI-RS transmission power, it is necessary to reconfigure the RRC parameters. However, this process may involve considerable delay (e.g., tens of milliseconds). To solve this problem, a method of more dynamically indicating the CSI-RS transmission power value for the purpose of saving BS energy may be considered.

[0228] In one method, information about the CSI-RS transmission power value may be signaled by DCI or MAC CE. Specifically, an offset value (such as in powerControlOffsetSS) from the SSB transmission power (i.e., the SSB power value set by ss-PBCH-BlockPower or the SSB power value to which [Method #1] is applied) may be directly indicated by DCI or MAC CE. Alternatively, an offset value (e.g., -3dB, 0dB, or +3dB) from the previously signaled powerControlOffsetSS may be indicated by DCI or MAC CE.

[0229] Alternatively, information about CSI-RS transmission power can be provided indirectly by DCI or MAC CE through information such as antenna port or antenna element on / off, antenna port on / off, TRP on / off, or panel on / off of the BS. For example, when the number of antenna ports or antenna elements is reduced by half, this may mean that the CSI-RS power value is reduced by 3dB.

[0230] Considering the processing time of the DCI or MAC CE at the UE and / or the processing time for changing the power value at the BS, there may be a question about when to apply the CSI-RS power value sent with the signal. For this purpose, information about the time point when the CSI-RS power is applied can be provided directly by the DCI and / or MAC CE, or preconfigured or predefined. For example, it can be predefined to apply the changed CSI-RS power k time slots after the time slot in which the DCI and / or MAC CE is received, and the value of k can be preset. Alternatively, for example, it can be defined to apply the changed CSI-RS power at the first frame boundary after the reception time of the DCI and / or MAC CE, at the first SFN=0 after the reception time of the DCI and / or MAC CE, or at the beginning of the first SI modification period after the reception time of the DCI and / or MAC CE.

[0231] Considering a UE in an idle or inactive state, information about the CSI-RS transmission power value and / or information about the time to apply the power value can be provided by broadcast data such as a PDCCH scheduling SI and / or a PDSCH carrying SI and / or a PDSCH including paging DCI and / or a paging message, or by a DCI scheduling broadcast data.

[0232] In the above method, DCI or MAC CE for providing information about CSI-RS transmission power value and / or information about the time of applying power value can be sent UE-specifically, UE group-commonly or cell-specifically. In the case of DCI, it can be sent by scrambling with RNTI configured UE-specifically, UE group-commonly or cell-specifically. In the case of MAC CE, it can be sent by PDSCH scheduled by DCI scrambled with RNTI configured UE-specifically, UE group-commonly or cell-specifically. In addition, PDSCH can also be scrambled with RNTI configured UE-specifically, UE group-commonly or cell-specifically.

[0233] In addition, the bit position in the DCI or MAC CE that provides information about the CSI-RS transmission power value and / or information about the time when the power value is applied can be preconfigured. In addition, the carrier / service cell carrying the DCI or MAC CE can be different from the carrier / service cell to which the information about the CSI-RS transmission power value is applied, and information about the CSI-RS transmission power value for multiple carriers / service cells can be provided by the DCI or MAC CE. For example, information about the transmission power value through a common CSI-RS can be provided for multiple carriers / service cells, or information about different CSI-RS transmission power values ​​can be provided for each carrier / service cell.

[0234] As illustrated in Table 3, in order to measure the DL path loss value, the UE may need the CSI-RS transmission power value and the RSRP (particularly CSI-RSRP) value that has been filtered by Layer 3 (L3). For example, when the referenceSignalPower value can be determined based on powerControlOffsetSS, if the powerControlOffsetSS value, the offset value from the previously signaled powerControlOffsetSS, or information about the CSI-RS SSB transmission power value can be provided through signaling such as (group common) DCI or MAC CE as in the proposed method, the UE can update the new powerControlOffsetSS value based on the indicated value, and also update the referenceSignalPower value and the DL path loss value based on the updated value.

[0235] The UE may perform CSI-RSRP and / or CSI-RSRQ and / or CSI-SINR measurements to calculate a DL path loss value. The measurements may correspond to L3 measurements and / or L1 measurements.

[0236] In this case, the value measured before the powerControlOffsetSS changes may not be used and the measurement may be restarted, or the L3 filter coefficient may be adjusted from the time the powerControlOffsetSS changes, or the filter coefficient may be set for a time point before / after the time the powerControlOffsetSS changes and the corresponding RRM may be performed.

[0237] Alternatively, information related to a timestamp of the time at which the UE performed the measurement or started filtering for the measurement may be included in the measurement report.The procedure may be equally extended to RRM for one or more neighboring cells and to RRM for the serving cell.

[0238] For one or more neighboring cells, information about the powerControlOffsetSS value, an offset value from the previously signaled powerControlOffsetSS, or information about the CSI-RS transmission power value may be provided through signaling such as (group common) DCI or MAC CE as in the proposed method. For example, when the information about the power value or offset value is provided by SI, the SI change may be notified through an SI modification message of paging.

[0239] According to the 3GPP TS 38.213 specification, when performing RLM and / or link recovery procedures or beam failure detection (BFD), the UE can determine whether the link quality is above or below a specific threshold based on the configured / defined DL signal. For example, in the case of RLM, the UE can determine whether the link quality is above Q_in or below Q_out. Or in the case of BFD, the UE can determine whether the link quality is above Q_in,LR or below Q_out,LR.

[0240] The UE may eventually declare a radio link failure or a beam failure based on how many times the event has occurred (ie, the counter value for the event) during a given time period (ie, the timer period).

[0241] When the absolute value of the CSI-RS transmission power or the offset value from the previously signaled powerControlOffsetSS or information about the CSI-RS transmission power value is provided by signaling such as (group common) DCI or MAC CE to dynamically change the powerControlOffsetSS value as in the proposed method, the threshold and / or timer value and / or counter value in the RLM / BFD process can also be adjusted (by prior agreement) based on the change of the powerControlOffsetSS value. For example, when the offset from the powerControlOffsetSS value is signaled to the UE as 3 dB, the UE can increase the threshold such as Q_in or Q_out or Q_in,LR or Q_out,LR by 3 dB when performing SSB-based RLM or BFD.

[0242] For switching of connected UEs, a method may be considered of sending a switching threshold or an offset value of a switching offset for a specific cell where CSI-RS power changes to the UE to appropriately trigger events such as A1, A2, or A3 (i.e., events A1 / A2 / A3 defined in Section 5.5.4 of 3GPP TS 38.331).

[0243] In the Release 17 5G NR standard, the value range of the parameter powerControlOffsetSS is {-3,0,3,6}dB. However, considering that the SSB transmission power value may be reduced due to NES, an offset value greater than 6dB may be required. For example, the value range can be changed to {-3,0,4,8}dB. For example, when the UE receives signaling informing that the BS has entered power saving mode or is operating in power saving mode, the value range can be changed, and the change in the value range can be configured / indicated separately.

[0244] Alternatively, considering that a CSI-RS transmission power value smaller than the SSB transmission power value is frequently used to save energy of the BS, an offset value less than -3 dB may be required. For example, the value range may be changed to {-6, -3, 0, 3} dB, and the value range may be changed when the UE receives signaling informing that the BS has entered power saving mode or is operating in power saving mode, and the change in the value range may be set / indicated separately.

[0245] Alternatively, both the minimum and maximum values ​​can be changed by combining the above two motivations (or methods). For example, the value range can be changed to {-4, 0, 4, 8} dB. When the UE receives a signaling informing that the BS has entered power saving mode or is operating in power saving mode by informing the change of the time axis on / off and / or the amount of frequency resources and / or the power increase and decrease and / or the antenna port on / off or the TRP on / off in the spatial domain, the value range can be changed, and the change of the value range can be set / indicated separately.

[0246] The CSI-RS power value may be changed by signaling. However, in another method, the power value of the CSI-RS may be implicitly changed according to the number of antenna ports to be turned off among the antenna ports of the CSI-RS and / or the index of the antenna ports that have been turned off. Alternatively, the power value of the CSI-RS may be implicitly changed according to the number of antenna ports or antenna elements, TRPs, or panels activated by the BS.

[0247] For example, for Fig.12 As shown in (a), a 32-port NZP CSI-RS is configured for each antenna port in one resource block (RB) and 14 symbols. A UE that receives a configuration / indication indicating that 16 antenna ports are turned off may use the configuration information or predefined / preconfigured rules to Fig.12 (b) or Fig.12 (c) performs 16-port NZP CSI-RS reception.

[0248] When the transmission power of each CSI-RS antenna port is fixed, the UE can Fig.12 In case (b), it can be seen that the CSI-RS transmission power has not changed. Fig.12 In case (c), the UE can recognize that the transmission power has changed by -3dB compared to the existing power. In another method, when the number of antenna ports used for CSI-RS resources or CSI-RS resource sets changes, or the number of antenna ports, antenna elements, TRPs, or panels activated by the BS changes, such as Fig.12 (b) or Fig.12As shown in (c), the offset value of the CSI-RS transmission power may be preconfigured / predefined according to each changing method.

[0249] The CSI-RS transmission power can also be changed according to the size of the actual activated bandwidth in the bandwidth part (BWP) / component carrier (CC). For example, when only 20 MHz is turned on in a 40-MHz BWP, a -3dB offset (i.e., by applying 10log 10 (20 / 40)) is implicitly applied to CSI-RS transmission power. Alternatively, the change value of CSI-RS transmission power can be preconfigured according to the size of the actually activated bandwidth.

[0250] Similar to RRM, when the NZP CSI-RS transmission power configured for CSI measurement changes, the change of the corresponding CSI measurement method can be considered.

[0251] For example, the UE may perform CSI measurement based on the NZP CSI-RS configured for channel measurement and / or interference measurement. In this case, the time axis measurement restriction may not be configured.

[0252] In this case, a value measured before the powerControlOffsetSS is changed may not be used, and average measurement or CSI measurement may be restarted from the time when the powerControlOffsetSS is changed.

[0253] Alternatively, when calculating the average value of the CSI measurement value, CSI measurement can also be performed on the CSI-RS whose transmission power value has changed by applying an appropriate weighting factor to the changed CSI-RS transmission power value. For example, when performing CSI averaging on a CSI-RS including a CSI-RS boosted by 3 dB, CSI measurement can be performed by applying half of the weighting factor to the CSI-RS. In other words, for averaging, a weighting factor of 1 can be applied to the CSI measurement in the CSI-RS before the transmission power value has changed, and a weighting factor based on the changed transmission power value can be applied to the CSI measurement after the transmission power value has changed.

[0254] Alternatively, information related to a timestamp of the time when the UE performs measurement or starts averaging measurement may be included in the measurement report.

[0255] The above method of performing CSI measurement can also be applied when the BS notifies the UE that it has entered power saving mode or is operating in power saving mode by signaling in the spatial domain of timeline on / off and / or changes in the amount of frequency resources and / or power increase / decrease and / or antenna port on / off or TRP on / off, and the UE also recognizes this.

[0256] In addition, the above method can be applied not only when there is a change in CSI-RS power but also when at least one of the time domain, frequency domain or spatial domain of CSI measurement changes. For example, when the CSI measurement window changes, the CSI can be measured again after the change, or the CSI can be measured after the change while considering a predetermined weighting factor and then averaged with the CSI measurement before the change.

[0257] In addition, when the frequency band or spatial domain used for CSI measurement or the power value of the corresponding NZP CSI-RS changes, the CSI after the change can be measured again, or the CSI after the change can be measured considering a predetermined weighting factor and then averaged with the CSI measurement before the change.

[0258] In case that some antenna ports are turned off to reduce power consumption of the BS and there is no CSI report corresponding to the antenna ports, when the BS reactivates the deactivated antenna ports due to an increase in data to be transmitted, the BS may not recognize appropriate CSI for transmitting data.

[0259] Taking this into consideration, the UE may have to receive CSI-RS resources or CSI-RS resource sets in which all antenna ports are activated by default and perform CSI reporting even for a relatively long period, instead of operating only CSI-RS resources or CSI-RS resource sets in which some antenna ports are deactivated or having a small number of antenna ports.

[0260] Therefore, rules can be set such that CSI-RS resources or CSI-RS resource sets and corresponding CSI reports for the default mode are configured, and the default mode always operates regardless of the BS being instructed to enter power saving mode or is operating in power saving mode by signaling in the spatial domain to indicate timing on / off and / or changes in the amount of frequency resources and / or power increase / decrease and / or antenna port on / off or TRP on / off.

[0261] [Method #2-1] Method of controlling NZP CSI-RS transmission power when different transmission powers can be set / indicated on a per SSB group index or per SSB index basis

[0262] When different transmission powers can be configured / indicated on a per SB group index or per SB index basis as in the above-mentioned [Method #1-1], the SSB index or SSB group index used as a reference can be determined when setting the transmission power value of the NZP-CSI-RS.

[0263] For example, when an offset value from an SSB transmission power value may be configured via parameter powerControlOffsetSS, an SSB group index or an SSB index or an SSB transmission power value may be needed as a reference.

[0264] That is, the CSI-RS transmission power can be determined based on a specific SSB group index or SSB index, and the SSB group index or SSB index can be set by higher layer signaling or predefined as the lowest or highest SSB index or the lowest or highest SSB group index. Alternatively, it can be predefined as the lowest or highest SSB index or the lowest or highest SSB group index among the actually transmitted SSBs (ATSS). Alternatively, it can be defined as the SSB index corresponding to the QCL source of the NZP-CSI-RS or the SSB group index including the SSB index. In this case, when the source RS of the NZP-CSI-RS is a signal / channel other than the SSB, the QCL source RS of the signal / channel can be continuously tracked so that the final source RS (ie, the final SSB) can be determined as the SSB group index or SSB index used to determine the CSI-RS transmission power.

[0265] As in [Method #2] above, information about the CSI-RS transmission power value may be signaled by DCI or MAC CE, or may be provided indirectly by DCI or MAC CE by providing information about antenna port or antenna element on / off or antenna port on / off or TRP on / off or panel on / off to the UE. Even in this case, it may be necessary to determine an SSB group index or SSB index used as a reference for signaling the CSI-RS transmission power value. In other words, the CSI-RS transmission power value may be determined based on a specific SSB group index or SSB index, and the SSB group index or SSB index may be configured by higher layer signaling or predefined as the lowest or highest SSB index or the lowest or highest SSB group index. Alternatively, it may be predefined as the lowest or highest SSB index or the lowest or highest SSB group index among the ATSS. Alternatively, it may be defined as an SSB index corresponding to the QCL source of the NZP-CSI-RS or an SSB group index including the SSB index. In this case, when the source RS of the NZP-CSI-RS is a signal / channel other than the SSB, the QCL source RS of the signal / channel can be continuously tracked so that the final source RS (i.e., the final SSB) can be determined as the SSB group index or SSB index used to determine the CSI-RS transmission power.

[0266] As in the above-mentioned [Method #1], [Method #1-1], [Method #2] and [Method #2-1], the method of controlling the transmission power of SSB and / or CSI-RS can be applied only when the NES state is indicated, only when a specific DRX configuration is indicated or applied, only when switching to a specific BWP is performed, or only during the DRX active time (or outside the DRX activation time) when DRX is configured. In this case, the DRX active time may mean a time period during which the ONDurationtimer and / or Inacitivitytimer is running, or a time period during which the UE should wake up to transmit and / or receive.

[0267] According to [Method #1] and [Method #2], because the transmission power of NZP CSI-RS and / or SSB changes dynamically and measurement is performed by considering the dynamically changed transmission power, the power consumption of the BS can be reduced and efficient channel measurement can be enabled without being affected by the dynamically changing power value.

[0268] [Method #3] Method for improving DL data reception performance by using enhanced reception techniques such as (digital) post-distortion at the UE

[0269] When the BS can know that the UE is capable of compensation techniques such as (digital) post-distortion, the BS can only send DL data to advanced UEs at a lower power value. Therefore, the probability of the BS's power amplifier (PA) operating in the nonlinear region may be reduced, which can help reduce power consumption.

[0270] Compensation techniques such as post-distortion may include the techniques proposed in H. Bouhadda, R. Zayani, H. Shaiek, D. Roviras, and R. Bouallegue, "Receiver Technique for Detection and Correction of Nonlinear High Power Amplifier Distortion Errors in OFDM Systems", 2015 IEEE, 81st Vehicular Technology Conference (VTC Spring), 2015, pp. 1-5.

[0271] The above proposed technique is a reception technique for compensating for non-linear high power amplifier distortion in an Orthogonal Frequency Division Multiplexing (OFDM) system.

[0272] This reception technique is used to detect nonlinearly distorted symbols among symbols received by a receiver (e.g., UE) in an OFDM transmission system. According to this method, the position of the erroneous symbol is determined, and the actual symbol is iteratively substituted into a specific synchronization equation until the error of the symbol is corrected (i.e., the symbol returns to the signal before it was distorted) based on the application of Bousguin's theorem and the fast Fourier transform (FFT). In the numerical performance evaluation of the above method, it has been verified that significant reception performance improvements compared to existing receivers are possible.

[0273] The performance of a UE capable of a compensation technique such as the above-described post distortion may be referred to as an advanced DL reception capability. In addition, a reception method of a UE to which the advanced DL reception capability is applied may be referred to as an advanced DL reception method.

[0274] When information on whether a power amplifier driven by a BS operates in a linear region or a nonlinear region can be indicated, the UE can apply an advanced DL reception method when receiving a linked DL signal / channel based on the information.

[0275] In addition, this information may be provided by a DCI that schedules or activates a DL signal / channel. In this case, when the UE receives the DCI, the UE may have to apply an advanced DL reception method when receiving a DL signal / channel scheduled or activated by the DCI, or meet the expected reception requirements when applying the advanced DL reception method.

[0276] Alternatively, the time period during which the advanced DL reception method is applied may be indicated by a (group common) DCI or MAC CE, and when the UE receives the indication, the UE may apply the advanced DL reception method when receiving DL signals / channels during the indicated time period, or meet the expected reception requirements when applying the advanced DL reception method.

[0277] Alternatively, it may be separately configured / indicated that an advanced DL reception method should be applied. Only when certain conditions (e.g., MCS and / or number of layers) are met, an advanced DL reception method may have to be applied when receiving a DL signal / channel, or the expected reception requirements may have to be met when applying the advanced DL reception method.

[0278] When the UE applies the advanced DL reception method, the time required to process the received DL signal / channel may increase compared to the existing processing. In consideration of this, when the UE applies the advanced DL reception method, the existing processing time may be relaxed.

[0279] For example, the processing time of N1 symbols (e.g., N1 is the PDSCH to HARQ-ACK timing) may increase by d_x (e.g., d_x=1 symbol). The d_x value may vary depending on the number of layers of the PDSCH received by the UE. This is because the processing complexity of the UE may increase as the number of layers increases. For example, when the number of layers is equal to or less than a certain threshold, d_x=K1 symbols may be defined; and when the number of layers is greater than a certain threshold, d_x=K2 (>K1) symbols may be defined. K2 is greater than K1.

[0280] In order to apply the advanced DL reception method, the UE should be able to obtain PA information, such as the method of installing the PA at the BS or the input power and output power curve of the PA. For this purpose, the BS can inform the UE of the PA information. For example, the PA information can be information such as whether the PA is configured for each antenna port or antenna element or for each panel. Alternatively, the BS can indirectly inform the UE of the power curve of the PA by densely sending DL signals at different transmission powers during a specific time period.

[0281] For example, a total of 7 symbols of CSI-RS can be configured at 2-symbol intervals within 14 symbols of a specific time slot n, and the CSI-RS transmission power for each symbol can be preconfigured. For example, the first CSI-RS transmission power can be set to 8dBm, and the power boost can be set at 1-dB intervals. Therefore, the last 7th CSI-RS transmission power can be 14dBm. In this case, the UE can indirectly derive the power curve of the BS's PA from the reception of the CSI-RS in 7 symbols, and perform an advanced DL reception method through the curve.

[0282] According to [Method #3], DL reception performance can be consistently maintained even when the power consumption of the BS is reduced.

[0283] [Method #4] A method of defining UE assistance information indicating UE preference for BS power and transmitting the information by the UE to the BS

[0284] When the power of the PDSCH received by the UE at a specific time point is large enough or small enough, the UE can report its preferred offset value. For example, when receiving a specific PDSCH, when the UE determines that the same reception success rate is guaranteed with a power lower or higher than the power of the PDSCH by XdB, the UE can report the X value to the BS.

[0285] The BS may send PDSCH to the UE at a lower or higher power based on the reported X value, thereby reducing power consumption or ensuring stable PDSCH reception. When the BS configures the UE to report the X value, the UE may periodically report the X value through a UL signal / channel such as PUCCH or PUSCH. Alternatively, the UE may periodically send an event-triggered report through a UL signal / channel such as PUCCH or PUSCH only when the X value is greater than or less than a preset / predefined threshold.

[0286] The UE may inform the BS of the power headroom to inform the BS that when the BS further reduces the transmission power of a DL signal such as SSB, the UE may not attach to the cell. In other words, the UE may inform the BS of the power headroom for the purpose of warning that the UE may have to perform a handover or may trigger a radio link failure (RLF) or beam failure detection (BFD) when the BS reduces the transmission power of a DL signal such as SSB.

[0287] For example, to inform the BS that when the BS reduces the SSB transmission power by Y dB, the UE may not be able to stably attach to the cell, and thus the UE may have to perform a handover or may trigger RLM of BFD, as determined by the UE, the UE may periodically or aperiodically report the Y value to the BS via PUSCH or PUCCH.

[0288] The UE assistance information proposed in the above method or the UE assistance information supported in Rel-17 (eg, maximum aggregation bandwidth, maximum number of CCs or maximum number of MIMO layers) may be sent to the BS via an RRC message or via a MAC CE or L1 message.

[0289] According to [Method #4], the BS can determine whether to reduce power and the degree of power reduction based on the reception performance of the DL signal and the connection status between the UE and the BS, thereby reducing the overall power consumption of the BS while achieving stable signal transmission and reception.

[0290] [Method 5] Based on signaling that the BS has entered the power saving mode or is operating in the power saving mode, a method of differently applying the RS used for path loss measurement and / or the DL RS required for performing RLM / BFD through signaling such as time axis on / off and / or change in the amount of frequency resources and / or power increase / decrease and / or antenna port on / off or TRP on / off in the spatial domain, and / or signaling of the BS's antenna port or antenna element on / off or antenna port on / off or TRP on / off or panel on / off informed by DCI or MAC CE, and / or signaling indicating by DCI or MAC CE that the power amount of the BS's DL signal (e.g., CSI-RS or SSB) has changed.

[0291] For example, two configurations for the RS for path loss measurement and the DL RS required for performing RLM / BFD can be configured for the UE. The UE can perform UL power control based on the RS for power loss measurement or perform RLM / BFD operations based on the DL RS by applying configuration #1 when the BS is in power saving mode or applying configuration #2 otherwise.

[0292] In another example, different maximum numbers of DL RSs required to perform RLM / BFD may be configured depending on whether the BS is in power saving mode. Specifically, when the BS is in power saving mode, the UE may perform RLM / BFD operations based on up to 2 DL RSs, and when the BS is not in power saving mode, the UE may perform RLM / BFD operations based on up to 4 DL RSs.

[0293] According to [Method #5], the amount of power allocated by DL RS can be kept constant by changing the DL RS received by the UE and the RLM / RFD operation of the UE depending on whether the BS is in power saving mode, and the number of antenna ports allocated with DL RS can be adjusted by changing the amount of DL RS depending on the number of antenna ports that are turned on, thereby achieving efficient DL transmission.

[0294] The various descriptions, functions, processes, proposals, methods and / or operational flowcharts of the present disclosure described herein may be applied to, but not limited to, various fields requiring wireless communication / connectivity between devices (e.g., 5G).

[0295] More specific examples will be described below with reference to the accompanying drawings. In the following drawings / descriptions, similar reference numerals represent the same or corresponding hardware blocks, software blocks or functional blocks unless otherwise specified.

[0296] Fig.13 The diagram shows a communication system 1 applied to the present disclosure.

[0297] refer to Fig.13, the communication system 1 applied to the present disclosure includes a wireless device, a BS and a network. A wireless device is a device that performs communication using a radio access technology (RAT) (e.g., 5G NR (or new RAT) or LTE), also referred to as a communication / radio / 5G device. The wireless device may include, but is not limited to, a robot 100a, a vehicle 100b-1 and 100b-2, an extended reality (XR) device 100c, a handheld device 100d, a home appliance 100e, an IoT device 100f, an artificial intelligence (AI) device / server 400. For example, a vehicle may include a vehicle with a wireless communication function, an autonomous driving vehicle, and a vehicle capable of performing vehicle-to-vehicle (V2V) communication. Here, a vehicle may include an unmanned aerial vehicle (UAV) (e.g., a drone). XR devices may include augmented reality (AR) / virtual reality (VR) / mixed reality (MR) devices and may be implemented in the form of a head-mounted device (HMD), a head-up display (HUD) installed in a vehicle, a television (TV), a smartphone, a computer, a wearable device, a home appliance, a digital signage, a vehicle, a robot, and the like. Handheld devices may include smart phones, smart boards, wearable devices (e.g., smart watches or smart glasses), and computers (e.g., laptops). Home appliances may include televisions, refrigerators, washing machines, etc. IoT devices may include sensors, smart meters, etc. For example, the BS and the network may be implemented as wireless devices, and a specific wireless device 200a may serve as a BS / network node for other wireless devices.

[0298] The wireless devices 100a to 100f may be connected to the network 300 via the BS 200. AI technology may be applied to the wireless devices 100a to 100f, and the wireless devices 100a to 100f may be connected to the AI ​​server 400 via the network 300. The network 300 may be configured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g., NR) network. Although the wireless devices 100a to 100f may communicate with each other via the BS 200 / network 300, the wireless devices 100a to 100f may perform direct communication (e.g., side link communication) with each other without the intervention of the BS / network. For example, the vehicles 100b-1 and 100b-2 may perform direct communication (e.g., V2V / vehicle-to-everything (V2X) communication). An IoT device (e.g., a sensor) may perform direct communication with other IoT devices (e.g., a sensor) or other wireless devices 100a to 100f.

[0299] Wireless communication / connection 150a, 150b and 150c can be established between wireless devices 100a to 100f / BS200 and between BS200. Here, wireless communication / connection can be established through various RATs (e.g., 5G NR) such as UL / DL communication 150a, side link communication 150b (or D2D communication) or inter-BS communication 150c (e.g., relay or integrated access backhaul (IAB). Wireless signals can be sent and received between wireless devices, between wireless devices and BSs, and between BSs through wireless communication / connection 150a, 150b and 150c. For example, signals can be sent and received on various physical channels through wireless communication / connection 150a, 150b and 150c. To this end, various configuration information configuration processes for sending / receiving wireless signals, various signal processing processes (e.g., channel coding / decoding, modulation / demodulation and resource mapping / demapping), and at least a part of the resource allocation process can be performed based on various suggestions of the present disclosure.

[0300] Fig.14 The diagram illustrates a wireless device suitable for use with the present disclosure.

[0301] refer to Fig.14 , the first wireless device 100 and the second wireless device 200 can transmit wireless signals through various RATs (e.g., LTE and NR). {The first wireless device 100 and the second wireless device 200} may correspond to Fig.13 {wireless device 100x and BS200} and / or {wireless device 100x and wireless device 100x}.

[0302] The first wireless device 100 may include one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106, and may be configured to implement the descriptions, functions, processes, proposals, methods and / or operational flow charts disclosed in this document. For example, the processor 102 may process the information in the memory 104 to generate first information / signals, and then transmit a wireless signal including the first information / signals through the transceiver 106. The processor 102 may receive a wireless signal including second information / signals through the transceiver 106, and then store information obtained by processing the second information / signals in the memory 104. The memory 104 may be connected to the processor 102 and store a plurality of pieces of information related to the operation of the processor 102. For example, the memory 104 may store software code including instructions for executing part or all of the processes controlled by the processor 102 or for executing the descriptions, functions, processes, proposals, methods, and / or operational flow charts disclosed in this document. The processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 106 may be connected to the processor 102 and send and / or receive wireless signals through one or more 108. Each of the transceivers 106 may include a transmitter and / or a receiver. The transceiver 106 may be used interchangeably with a radio frequency (RF) unit. In the present disclosure, a wireless device may be a communication modem / circuit / chip.

[0303] Specifically, instructions and / or operations controlled by the processor 102 of the first wireless device 100 and stored in the memory 104 of the first wireless device 100 according to an embodiment of the present disclosure will be described.

[0304] Although the following operations are described based on the control operations of the processor 102 in terms of the processor 102, software codes for performing such operations may be stored in the memory 104. For example, in the present disclosure, at least one memory 104 may be a computer-readable storage medium and may store instructions or programs. When the instructions or programs are executed, at least one processor operably connected to at least one memory may perform operations related to the following operations according to embodiments or implementations of the present disclosure.

[0305] For example, the processor 102 may receive an RRC parameter for transmission power related to a DL signal through the transceiver 106. For example, the RRC parameter may be a parameter related to transmission power of an SSB and / or a parameter related to transmission power of a CSI-RS.

[0306] The processor 102 may receive DCI or MAC CE for power control related to the DL signal through the transceiver 106. In addition, the processor 102 may receive the DL signal through the transceiver 106. In addition, the processor 102 may report measurement information related to the DL signal through the transceiver 106.

[0307] The above-mentioned DL signal may be SSB and / or CSI-RS and / or PDSCH.

[0308] When the DL signal is SSB and / or CSI-RS, the above operation of the processor 102 may be based on at least one of [Method #1] to [Method #5].

[0309] When the DL signal is a PDSCH, the above operation of the processor 102 may be based on at least one of [method #3] or [method #4]. For example, in this case, the processor 102 may skip receiving RRC parameters and receiving DCI or MAC CE. In addition, the measurement information reported by the processor 102 may be a report related to the power of the PDSCH.

[0310] The second wireless device 200 may include one or more processors 202 and one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206, and may be configured to implement the descriptions, functions, processes, proposals, methods and / or operational flow charts disclosed in this document. For example, the processor 202 may process the information in the memory 204 to generate third information / signals, and then send a wireless signal including the third information / signals through the transceiver 206. The processor 202 may receive a wireless signal including fourth information / signals through the transceiver 106, and then store information obtained by processing the fourth information / signals in the memory 204. The memory 204 may be connected to the processor 202, and store various information related to the operation of the processor 202. For example, the memory 204 may store software code including instructions for executing part or all of the processes controlled by the processor 202 or for executing the descriptions, functions, processes, proposals, methods and / or operational flow charts disclosed in this document. The processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement a RAT (e.g., LTE or NR). The transceiver 206 may be connected to the processor 202 and send and / or receive wireless signals through one or more antennas 208. Each of the transceivers 206 may include a transmitter and / or a receiver. The transceiver 206 may be used interchangeably with an RF unit. In the present disclosure, a wireless device may be a communication modem / circuit / chip.

[0311] Specifically, instructions and / or operations controlled by the processor 202 of the second wireless device 200 and stored in the memory 204 of the second wireless device 200 according to an embodiment of the present disclosure will be described.

[0312] Although the following operations are described based on the control operations of the processor 202 in terms of the processor 202, software codes for performing such operations may be stored in the memory 204. For example, in the present disclosure, at least one memory 204 may be a computer-readable storage medium and may store instructions or programs. The instructions or programs, when executed, may enable at least one processor operably connected to at least one memory to perform operations related to the following operations according to an embodiment or implementation of the present disclosure.

[0313] For example, the processor 202 may send an RRC parameter for transmission power related to a DL signal through the transceiver 206. For example, the RRC parameter may be a parameter related to transmission power of an SSB and / or a parameter related to transmission power of a CSI-RS.

[0314] The processor 202 may transmit DCI or MAC CE for power control related to the DL signal through the transceiver 206. In addition, the processor 202 may transmit the DL signal through the transceiver 206. In addition, the processor 202 may receive measurement information related to the DL signal through the transceiver 206.

[0315] The above-mentioned DL signal may be SSB and / or CSI-RS and / or PDSCH.

[0316] When the DL signal is SSB and / or CSI-RS, the above operation of the processor 202 may be based on at least one of [Method #1] to [Method #5].

[0317] When the DL signal is a PDSCH, the above operation of the processor 202 may be based on at least one of [method #3] or [method #4]. For example, in this case, the processor 202 may skip the transmission of RRC parameters and the transmission of DCI or MAC CE. In addition, the measurement information reported by the processor 202 may be a report related to the power of the PDSCH.

[0318] Now, the hardware elements of the wireless devices 100 and 200 will be described in more detail. One or more protocol layers may be implemented by, but not limited to, one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as physical (PHY), medium access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), RRC, and service data adaptation protocol (SDAP)). One or more processors 102 and 202 may generate one or more protocol data units (PDUs) and / or one or more service data units (SDUs) according to the descriptions, functions, processes, proposals, methods, and / or operational flow charts disclosed in this document. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or operational flow charts disclosed in this document and provide the messages, control information, data, or information to one or more transceivers 106 and 206. The one or more processors 102 and 202 may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the description, functions, procedures, proposals, methods, and / or operational flow charts disclosed in this document and provide the generated signal to the one or more transceivers 106 and 206. The one or more processors 102 and 202 may receive a signal (e.g., a baseband signal) from the one or more transceivers 106 and 206 and obtain the PDU, SDU, message, control information, data, or information according to the description, functions, procedures, proposals, methods, and / or operational flow charts disclosed in this document.

[0319] One or more processors 102 and 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more application specific integrated circuits (ASICs), one or more digital signal processors (DSPs), one or more digital signal processing devices (DSPDs), one or more programmable logic devices (PLDs), or one or more field programmable gate arrays (FPGAs) may be included in one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document may be implemented using firmware or software, and the firmware or software may be configured to include modules, processes, or functions. Firmware or software configured to execute the descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document may be included in one or more processors 102 and 202, or may be stored in one or more memories 104 and executed by one or more processors 102 and 202. The descriptions, functions, processes, proposals, methods, and / or operational flowcharts disclosed in this document may be implemented using firmware or software in the form of code, instructions, and / or instruction sets.

[0320] One or more memories 104 and 204 may be connected to one or more processors 102 and 202 and store various types of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories 104 and 204 may be configured to include read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EPROM), flash memory, hard drive, registers, cache memory, computer-readable storage media, and / or combinations thereof. One or more memories 104 and 204 may be located inside and / or outside of one or more processors 102 and 202. One or more memories 104 and 204 may be connected to one or more processors 102 and 202 via various technologies such as wired or wireless connections.

[0321] One or more transceivers 106 and 206 may send user data, control information, and / or wireless signals / channels mentioned in the methods and / or operational flow charts of this document to one or more other devices. One or more transceivers 106 and 206 may receive user data, control information, and / or wireless signals / channels mentioned in the description, descriptions, functions, processes, proposals, methods, and / or operational flow charts disclosed in this document from one or more other devices. For example, one or more transceivers 106 and 206 may be connected to one or more processors 102 and 202, and send and receive wireless signals. For example, one or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 send user data, control information, or wireless signals to one or more other devices. One or more processors 102 and 202 may perform control so that one or more transceivers 106 and 206 can receive user data, control information, or wireless signals from one or more other devices. One or more transceivers 106 and 206 may be connected to one or more antennas 108 and 208, and one or more transceivers 106 and 206 may be configured to send and receive user data, control information, and / or wireless signals / channels mentioned in the descriptions, functions, processes, and suggestions disclosed in this document through one or more antennas 108 and 208. In this document, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106 and 206 may convert received wireless signals / channels, etc. from RF band signals to baseband signals so as to process received user data, control information, and wireless signals / channels using one or more processors 102 and 202. One or more transceivers 106 and 206 may convert user data, control information, wireless signals / channels processed using one or more processors 102 and 202 from baseband signals to RF band signals. To this end, one or more transceivers 106 and 206 may include (analog) oscillators and / or filters.

[0322] Fig.15 The diagram is applied to a vehicle or an autonomous vehicle of the present disclosure. The vehicle or the autonomous vehicle may be implemented as a mobile robot, a car, a train, a manned / unmanned aerial vehicle (AV), a ship, etc.

[0323] refer to Fig.15 The vehicle or autonomous driving vehicle 100 may include an antenna unit 108, a communication unit 110, a control unit 120, a driving unit 140a, a power supply unit 140b, a sensor unit 140c, and an autonomous driving unit 140d. The antenna unit 108 may be configured as a part of the communication unit 110.

[0324] The communication unit 110 can send and receive signals (e.g., data and control signals) to and from external devices such as other vehicles, BSs (e.g., gNBs and roadside units), and servers. The control unit 120 can perform various operations by controlling elements of the vehicle or autonomous driving vehicle 100. The control unit 120 may include an ECU. The drive unit 140a may enable the vehicle or autonomous driving vehicle 100 to drive on a road. The drive unit 140a may include an engine, a motor, a powertrain, wheels, brakes, a steering device, etc. The power supply unit 140b may supply power to the vehicle or autonomous driving vehicle 100, and may include a wired / wireless charging circuit, a battery, etc. The sensor unit 140c may obtain information about vehicle status information, surrounding environment information, user information, etc. The sensor unit 140c may include an inertial measurement unit (IMU) sensor, a collision sensor, a wheel sensor, a speed sensor, a slope sensor, a weight sensor, a heading sensor, a position module, a vehicle forward / backward sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor, a temperature sensor, a humidity sensor, an ultrasonic sensor, an illumination sensor, a pedal position sensor, etc. The autonomous driving unit 140d may implement a technology for maintaining a lane on which the vehicle is driving, a technology for automatically adjusting a speed such as an adaptive cruise control, a technology for autonomously driving along a determined path, a technology for driving by automatically setting a path if a destination is set, and the like.

[0325] For example, the communication unit 110 may receive map data, traffic information data, etc. from an external server. The autonomous driving unit 140d may generate an autonomous driving route and a driving plan from the acquired data. The control unit 120 may control the drive unit 140a so that the vehicle or the autonomous driving vehicle 100 may move along the autonomous driving route according to the driving plan (e.g., speed / direction control). During autonomous driving, the communication unit 110 may obtain the latest traffic information data from an external server irregularly / irregularly, and may obtain surrounding traffic information data from neighboring vehicles. During autonomous driving, the sensor unit 140c may obtain information about vehicle state information and / or surrounding environment information. The autonomous driving unit 140d may update the autonomous driving route and driving plan based on the newly acquired data / information. The communication unit 110 may transmit information about the vehicle position, autonomous driving route, and / or driving plan to an external server. The external server may predict traffic information data using AI technology, etc. based on information collected from the vehicle or autonomous driving vehicle, and provide the predicted traffic information data to the vehicle or autonomous driving vehicle.

[0326] The embodiments of the present disclosure described below are combinations of elements and features of the present disclosure. Unless otherwise stated, these elements or features may be considered as selective. Each element or feature may be practiced without being combined with other elements or features. In addition, the embodiments of the present disclosure may be constructed by combining a part of elements and / or features. The order of operations described in the embodiments of the present disclosure may be rearranged. Some constructions of any one embodiment may be included in another embodiment and may be replaced by the corresponding constructions of another embodiment. It will be apparent to those skilled in the art that claims that are not explicitly referenced to each other in the attached claims may be presented in combination as embodiments of the present disclosure, or may be included as new claims by subsequent amendments after the application is submitted.

[0327] In the present disclosure, in some cases, a specific operation described as being performed by a BS may be performed by an upper node of the BS. That is, it is apparent that in a network consisting of a plurality of network nodes including a BS, various operations performed for communication with an MS may be performed by the BS or network nodes other than the BS. The term "BS" may be replaced with the term "fixed station", "Node B", "enhanced Node B (eNodeB or eNB)", "access point", etc.

[0328] Those skilled in the art will appreciate that the present disclosure can be performed in other specific ways different from the ways set forth herein without departing from the spirit and essential characteristics of the present disclosure. Therefore, the above embodiments are interpreted in all respects as illustrative and not restrictive. The scope of the present disclosure should be determined by the appended claims and their legal equivalents, rather than by the above description, and all changes falling within the meaning and equivalent range of the appended claims should be included therein.

[0329] Industrial Applicability

[0330] Although the above-mentioned method of transmitting and receiving a reference signal for channel state information and the apparatus thereof have been described based on an example applied to a 5G NR system, the method and apparatus are applicable to various wireless communication systems in addition to the 5G NR system.

Claims

1. A method for measuring channel state information (CSI) by a user equipment (UE) in a wireless communication system, the method comprising: receiving first information related to a first transmission power of a channel state information-reference signal (CSI-RS); receiving the CSI-RS; as well as starting measurement of a first CSI based on the first transmission power and the CSI-RS, Wherein, based on receiving second information related to a second transmission power of the CSI-RS having a value different from the first transmission power, a second CSI is measured based on the CSI-RS and the second transmission power.

2. The method according to claim 1, wherein: The measurement of the first CSI is ignored based on the measurement of the second CSI.

3. The method according to claim 1, wherein: The second CSI is measured based on a weighting factor corresponding to the second transmission power.

4. The method according to claim 1, wherein: The second CSI is transmitted together with a timestamp for a time point when measurement of the second CSI starts.

5. The method according to claim 1, wherein: The second information is applied at a time point before measurement of the first CSI is completed.

6. The method according to claim 1, wherein: The second transmission power is determined based on the first transmission power and the number of antenna ports turned on by a base station (BS).

7. A user equipment (UE) for measuring channel state information (CSI) in a wireless communication system, the UE comprising: at least one transceiver; at least one processor; as well as at least one memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations, The operations include: receiving, by the at least one transceiver, first information related to a first transmission power of a channel state information-reference signal (CSI-RS); receiving the CSI-RS by the at least one transceiver; and starting measurement of a first CSI based on the first transmission power and the CSI-RS, and Wherein, based on receiving second information related to a second transmission power of the CSI-RS having a value different from the first transmission power, a second CSI is measured based on the CSI-RS and the second transmission power.

8. The UE according to claim 7, wherein: The measurement of the first CSI is ignored based on the measurement of the second CSI.

9. The UE according to claim 7, wherein: The second CSI is measured based on a weighting factor corresponding to the second transmission power.

10. The UE according to claim 7, wherein: The second CSI is transmitted together with a timestamp for a time point when measurement of the second CSI starts.

11. The UE according to claim 7, wherein: The second information is applied at a time point before measurement of the first CSI is completed.

12. The UE according to claim 7, wherein: The second transmission power is determined based on the first transmission power and the number of antenna ports turned on by a base station (BS).

13. An apparatus for measuring channel state information (CSI) in a wireless communication system, the apparatus comprising: at least one processor; as well as at least one memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations, The operations include: receiving first information related to a first transmission power of a channel state information-reference signal (CSI-RS); receiving the CSI-RS; and starting measurement of a first CSI based on the first transmission power and the CSI-RS, and Wherein, based on receiving second information related to a second transmission power of the CSI-RS having a value different from the first transmission power, a second CSI is measured based on the CSI-RS and the second transmission power.

14. A computer-readable storage medium comprising at least one computer program, the at least one computer program causing at least one processor to perform operations, in, The operations include: receiving first information related to a first transmission power of a channel state information-reference signal (CSI-RS); receiving the CSI-RS; and starting measurement of a first CSI based on the first transmission power and the CSI-RS, and Wherein, based on receiving second information related to a second transmission power of the CSI-RS having a value different from the first transmission power, a second CSI is measured based on the CSI-RS and the second transmission power.

15. A method for receiving channel state information (CSI) by a base station (BS) in a wireless communication system, the method comprising: sending first information related to a first transmission power of a channel state information-reference signal (CSI-RS); Sending the CSI-RS; sending second information related to a second transmission power of the CSI-RS having a value different from the first transmission power; as well as receiving the CSI based on the CSI-RS, The CSI includes measurement information based on the CSI-RS and the second transmission power.

16. A base station (BS) for receiving channel state information (CSI) in a wireless communication system, the BS comprising: at least one transceiver; at least one processor; as well as at least one memory operably connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations, The operations include: transmitting, by the at least one transceiver, first information related to a first transmission power of a channel state information-reference signal (CSI-RS); transmitting the CSI-RS by the at least one transceiver; transmitting, by the at least one transceiver, second information related to a second transmission power of the CSI-RS having a value different from the first transmission power; and receiving the CSI based on the CSI-RS by the at least one transceiver, and The CSI includes measurement information based on the CSI-RS and the second transmission power.

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