Operation related to CSI-RS-based measurements

Abstract

Embodiments of the present disclosure relate to operations associated with channel state information (CSI) reference signal (RS)-based measurements. In one aspect of the present disclosure, a terminal device determines that one or more CSI-RSs are not received from a cell, and the terminal device is configured to perform CSI-RS-based measurements by monitoring at least one CSI-RS from the cell. Based on determining that the one or more CSI-RSs are not received, the terminal device performs an operation related to the CSI-RS-based measurement based on at least one of (i) an SSB-based measurement from the cell, or (ii) whether the terminal device is aware of a DTX configuration of the cell. By using SSB-based measurements to determine CSI-RS measurement behavior, network energy savings are improved, and time is saved. Therefore, the communication efficiency is improved.

Description

Technical Field

[0001] Embodiments of this disclosure generally relate to the field of communications, and particularly to a terminal device, method, apparatus, and computer-readable storage medium for performing operations associated with measurements based on channel state information (CSI) reference signals (RS). Background Technology

[0002] With the development of communication technology, many services have relatively high requirements for network energy efficiency. Discontinuous Transmission (DTX) and Discontinuous Reception (DRX) have been introduced to improve network energy efficiency. Current research objectives include studying the alignment of cell DTX / DRX with user equipment (UE) DRX in RRC_CONNECTED mode, as well as the inter-node information exchange regarding cell DTX / DRX. UEs can be expected not to transmit or receive certain signals or channels (e.g., CSI-RS) during inactive periods of cell DTX / DRX.

[0003] However, to avoid or minimize the impact of cell DTX / DRX on CSI-RS-based measurements, further improvements to CSI-RS-based measurement solutions are still needed. Summary of the Invention

[0004] Overall, exemplary embodiments of this disclosure provide a solution for performing operations related to CSI-RS-based measurements.

[0005] In a first aspect, a terminal device is provided. The terminal device includes at least one processor and at least one memory storing instructions, which, when executed by the at least one processor, cause the terminal device to at least: determine that one or more Channel State Information (CSI) Reference Signals (RS) are not received from a cell, wherein the terminal device is configured to perform CSI-RS-based measurements by monitoring at least one CSI-RS from the cell; and based on the determination that the one or more CSI-RS are not received, perform operations related to the CSI-RS-based measurements based on at least one of: (i) measurements based on Synchronization Signal / Physical Broadcast Channel (PBCH) Blocks (SSBs) from the cell, or (ii) whether the terminal device is aware of the Discontinuous Transmission (DTX) configuration of the cell.

[0006] In a second aspect, a method is provided. The method includes: determining at a terminal device that one or more Channel State Information (CSI) Reference Signals (RS) have not been received from a cell, wherein the terminal device is configured to perform CSI-RS-based measurements by monitoring at least one CSI-RS from the cell; and based on the determination that the one or more CSI-RS have not been received, performing operations related to the CSI-RS-based measurements based on at least one of: (i) measurements based on Synchronization Signal / Physical Broadcast Channel (PBCH) blocks (SSBs) from the cell, or (ii) whether the terminal device is aware of the cell's Discontinuous Transmission (DTX) configuration.

[0007] In a third aspect, an apparatus is provided. The apparatus includes: components for determining at a terminal device that one or more Channel State Information (CSI) Reference Signals (RS) have not been received from a cell, wherein the terminal device is configured to perform CSI-RS-based measurements by monitoring at least one CSI-RS from the cell; and components for performing operations related to the CSI-RS-based measurements based on determining that the one or more CSI-RS have not been received, based on at least one of: (i) measurements based on Synchronization Signal / Physical Broadcast Channel (PBCH) Blocks (SSBs) from the cell, or (ii) whether the terminal device is aware of the Discontinuous Transmission (DTX) configuration of the cell.

[0008] In a fourth aspect, a non-transitory computer-readable medium is provided, including program instructions for causing a device to perform at least the method according to the second aspect above.

[0009] In a fifth aspect, a computer program is provided, including instructions that, when executed by an apparatus, cause the apparatus to at least: determine that one or more Channel State Information (CSI) Reference Signals (RS) have not been received from a cell, wherein the terminal device is configured to perform CSI-RS-based measurements by monitoring at least one CSI-RS from the cell; and based on the determination that the one or more CSI-RS have not been received, perform operations related to the CSI-RS-based measurements based on at least one of: (i) measurements based on Synchronization Signal / Physical Broadcast Channel (PBCH) Blocks (SSBs) from the cell, or (ii) whether the terminal device is aware of the Discontinuous Transmission (DTX) configuration of the cell.

[0010] In a sixth aspect, a terminal device is provided. The terminal device includes: a determining circuitry configured to determine at the terminal device that one or more Channel State Information (CSI) Reference Signals (RS) have not been received from a cell, wherein the terminal device is configured to perform CSI-RS-based measurements by monitoring at least one CSI-RS from the cell; and an execution circuitry configured to, based on the determination that the one or more CSI-RS have not been received, perform operations related to the CSI-RS-based measurements based on at least one of: (i) measurements based on Synchronization Signal / Physical Broadcast Channel (PBCH) Blocks (SSBs) from the cell, or (ii) whether the terminal device is aware of the cell's Discontinuous Transmission (DTX) configuration.

[0011] It should be understood that the summary section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0012] Some exemplary embodiments will now be described with reference to the accompanying drawings, in which:

[0013] Figure 1A An example network environment is shown that can implement example embodiments of this disclosure;

[0014] Figure 1B Example scenarios of CSI-RS measurements related to some embodiments of this disclosure are shown;

[0015] Figure 2 A flowchart is shown illustrating a method implemented at a terminal device according to some embodiments of the present disclosure;

[0016] Figure 3 Example procedures for CSI-RS-based measurements according to some embodiments of this disclosure are shown;

[0017] Figure 4 Another example procedure for CSI-RS-based measurements according to some embodiments of this disclosure is shown;

[0018] Figure 5 An example flowchart of CSI-RS-based measurements according to some embodiments of the present disclosure is shown;

[0019] Figure 6 Another example flowchart of CSI-RS-based measurements according to some embodiments of this disclosure is shown;

[0020] Figure 7 A simplified block diagram of an apparatus suitable for implementing embodiments of the present disclosure is shown; and

[0021] Figure 8 A block diagram of an example computer-readable medium according to some embodiments of the present disclosure is shown.

[0022] In all the accompanying drawings, the same or similar reference numerals denote the same or similar elements. Detailed Implementation

[0023] The principles of this disclosure will now be described with reference to some exemplary embodiments. It should be understood that these embodiments are described for illustrative purposes only and to assist those skilled in the art in understanding and implementing this disclosure, and do not imply any limitation on the scope of this disclosure. The disclosure described herein can be implemented in various ways other than those described below.

[0024] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0025] References to "an embodiment," "embodiment," "example embodiment," etc., in this disclosure indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment must include that particular feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same embodiment. Moreover, when a particular feature, structure, or characteristic is described in connection with an embodiment, it should be understood that such a feature, structure, or characteristic can be implemented in conjunction with other embodiments, whether explicitly described or not, to the knowledge of those skilled in the art.

[0026] It should be understood that although the terms “first” and “second” may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of the exemplary embodiments. As used herein, the term “and / or” includes any and all combinations of one or more of the listed terms.

[0027] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that, as used herein, the terms “comprising,” “including,” “having,” “possessing,” “comprises,” and / or “contains” designate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. As used herein, “at least one of the following: ” and “at least one of ” and similar wording (where the list of two or more elements is connected by “and” or “or”) means at least any one of these elements, or at least any two or more of these elements, or at least all of these elements.

[0028] As used in this application, the term "circuit system" may refer to one or more or all of the following: (a) Hardware circuit implementation only (such as implementation only in analog and / or digital circuit systems) and (b) A combination of hardware circuitry and software, such as (if applicable): (i) A combination of (multiple) analog and / or digital hardware circuits with software / firmware, and (ii) Any part of the hardware processor(s) having software (including (multiple) digital signal processors), software, and (multiple) memories work together to enable a device (such as a mobile phone or server) to perform various functions, and (c) (a) multiple) hardware circuits and / or (a) multiple processors, such as (a) multiple microprocessors or a portion thereof, which require software (e.g. firmware) to operate, but may be absent when operation is not required.

[0029] This definition of circuit system applies to all uses of the term in this application (including in any claim). As a further example, as used in this application, the term circuit system also covers only hardware circuitry or a processor (or processors) or a portion of hardware circuitry or a processor and its accompanying software and / or firmware implementation. For example, if applicable to a particular claim element, the term circuit system also covers baseband integrated circuits or processor integrated circuits for mobile devices, or similar integrated circuits in servers, cellular network devices, or other computing or network devices.

[0030] As used herein, the term "communication network" refers to a network that conforms to any suitable communication standard, such as Long Term Evolution (LTE), LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), etc. Furthermore, communication between terminal devices and network devices in a communication network can be performed according to any suitable generation of communication protocol, including but not limited to third-generation (3G), fourth-generation (4G), 4.5G, fifth-generation (5G) communication protocols and / or higher versions. Embodiments of this disclosure can be applied to various communication systems. Given the rapid development of communications, future types of communication technologies and systems will naturally exist, in which this disclosure may be embodied. The scope of this disclosure should not be construed as limited to the systems described above.

[0031] As used herein, the term "network device" refers to a node in a communication network through which terminal devices access the network and receive services. Network devices can refer to base stations (BS) or access points (APs), such as Node B (NodeB or NB), evolved Node B (eNodeB or eNB), NR NB (also known as gNB), Remote Radio Unit (RRU), Radio Headend (RH), Remote Radio Headend (RRH), relay, low-power nodes (such as femtoseconds, picoseconds), etc., depending on the terminology and technology used.

[0032] The term "terminal device" refers to any terminal device that may be capable of wireless communication. As an example and not a limitation, a terminal device may also be referred to as a communication device, user equipment (UE), subscriber station (SS), portable subscriber station, mobile station (MS), or access terminal (AT). Terminal devices can include, but are not limited to, mobile phones, cellular phones, smartphones, Voice over IP (VoIP) phones, wireless local loop phones, tablets, wearable terminal devices, personal digital assistants (PDAs), portable computers, desktop computers, image capture terminal devices (such as digital cameras), gaming terminal devices, music storage and playback devices, in-vehicle wireless terminal devices, wireless endpoints, mobile stations, laptop embedded devices (LEE), laptop mounted devices (LME), USB dongles, smart devices, wireless customer premises equipment (CPE), Internet of Things (IoT) devices, watches or other wearable devices, head-mounted displays (HMDs), vehicles, drones, medical devices and applications (such as remote surgery), industrial devices and applications (such as robots and / or other wireless devices operating in industrial and / or automated processing chain environments), consumer electronics devices, devices operating on commercial and / or industrial wireless networks, etc. In the following description, the terms "terminal equipment", "communication equipment", "terminal", "user equipment" and "UE" are used interchangeably.

[0033] The term "DTX" refers to "Discontinuous Transmission." DTX is a power-saving mode for a base station, in which some components of the cell remain active to ensure timely response when needed. Cell DTX includes active and inactive periods. Periodic cell DTX can be configured by the gNB. The gNB can be expected to enable all transmissions for data services and reference signals during active periods. The gNB can be expected to disable at least some transmissions for data services and reference signals during inactive periods. It should be understood that in some embodiments of this disclosure, "inactive" may also be referred to as "inactive."

[0034] Figure 1A An example network environment 100 is shown that can implement exemplary embodiments of the present disclosure. Environment 100 may be part of a communication network, including terminal devices and network devices.

[0035] like Figure 1A As shown, the communication network 100 may include a terminal device 110 (hereinafter also referred to as UE 110). The communication network 100 may also include network devices 120 and 130 (hereinafter also referred to as gNB 120 and gNB 130). Network device 120 can manage cell 101, and network device 130 can manage cell 103. Terminal device 110 and network device 120 can communicate data and control information with each other within the coverage area of ​​cell 101. The link from network device 120 to terminal device 110 is called a downlink (DL), and the link from terminal device 110 to network device 120 is called an uplink (UL).

[0036] It should be understood that the number of network devices and terminal devices is for illustrative purposes only and does not imply any limitation. System 100 may include any suitable number of network devices and terminal devices to suit the implementation of embodiments of this disclosure. Although not shown, it will be understood that one or more terminal devices may be located in environment 100.

[0037] Communication in network environment 100 can be implemented according to any suitable communication protocol(s), including but not limited to third-generation (3G), fourth-generation (4G), fifth-generation (5G) or higher, wireless local area network communication protocols (such as IEEE 802.11), and / or any other currently known or future-developed protocols. Furthermore, communication can utilize any suitable wireless communication technology, including but not limited to: multiple-input multiple-output (MIMO), orthogonal frequency division multiplexing (OFDM), time division multiplexing (TDM), frequency division multiplexing (FDM), code division multiplexing (CDM), Bluetooth, ZigBee, and machine-type communication (MTC), enhanced mobile broadband (eMBB), massive machine-type communication (mMTC), ultra-reliable low-latency communication (URLLC), carrier aggregation (CA), dual connectivity (DC), and new radio unlicensed (NR-U) technologies.

[0038] Cell DTX and cell DRX have been introduced to improve network energy efficiency. Current research objectives include studying the alignment of cell DTX / DRX with UE DRX in RRC_CONNECTED mode, and the inter-node information exchange regarding cell DTX / DRX. Regarding cell DTX, SSB transmission remains unchanged due to cell DTX / DRX. Furthermore, the impact on idle / inactive UEs caused by the aforementioned enhancements should be avoided.

[0039] Regarding cell DTX and its impact on CSI-RS transmission and related UE measurements, the following agreements have been made: From the RAN2 perspective, cell DTX / DRX configuration and activation / deactivation:

[0040] However, if CSI-RS is not transmitted during the inactive period of cell DTX, UE measurement performance will be affected. This is likely to lead to performance degradation for UEs in neighboring cells, as UEs in neighboring cells may not be provided with cell DTX mode.

[0041] CSI-RS can be used for both L1 measurements and L3 mobility, and the example embodiments of this disclosure focus on CSI-RS-based measurements for L3 mobility (Radio Resource Management, RRM). However, this disclosure can also be applied to CSI-RS-based L1 measurements, such as L1-RSRP or L1-Signal-to-Interference-plus-Noise Ratio (SINR) measurements. A key issue for the UE is how to handle CSI-RS-based measurements if these CSI reference signals are discarded during periods of inactive cell DTX. The UE is aware of the DTX status of its serving cell but not the DTX status of neighboring cells where CSI-RS measurements are being performed. This depends on whether the cell DTX is dynamically configured and activated or statically configured and activated. RAN1 / 2 has defined cell DTX / DRX activation based on Radio Resource Control (RRC) and Downlink Control Information (DCI). Cell DTX / DRX modes are configured by RRC (a fairly static configuration for each cell), and cell DTX activation / deactivation is indicated by L1 signaling (e.g., DCI) or explicitly in the RRC configuration. RRC-based configuration enables neighbor cell state awareness by indicating neighbor cell DTX modes, which is impractical if cell state changes (e.g., activation or deactivation) occur frequently using DCI.

[0042] Figure 1B An example scenario is shown where CSI-RS measurements are taken during a period of inactivity in the cell DTX of a neighboring cell. Figure 1B The top is scenario 1, where the inactivity period of the neighboring cell's DTX is known to the UE, and... Figure 1B The bottom is scenario 2, where the cell DTX of a neighboring cell is unknown to the UE during inactive periods. For example, cell DTX is activated in a neighboring cell via L1 signaling, which is invisible to the UE.

[0043] Taking CSI-RS-based L3 measurement as an example, the UE is expected to collect (e.g.,) 5 samples on the measured RS and apply filtering (or averaging) to arrive at a result (e.g., average RSRP, reference signal reception quality, or SINR). This ensures that the measurement meets the measurement accuracy requirements specified in Clause 10 of TS38.133. However, when cell DTX is active, if the CSI-RS to be measured falls within a cell DTX inactivity period, the UE may not be able to obtain some samples. To ensure compliance with existing measurement accuracy requirements, the measurement time or measurement delay may need to be extended to obtain sufficient samples (e.g., 5 samples) for filtering. This will increase the measurement delay based on CSI-RS.

[0044] The problem is even worse if the UE is unaware of the activation / deactivation of cell DTX in neighboring cells. The UE simply continues to measure on the configured CSI-RS, and the CSI-RS during inactive periods will be measured with a low RSRP, thus incorrectly reducing the filtered measurement results.

[0045] According to some embodiments of this disclosure, a solution is provided for performing operations related to CSI-RS-based measurements. In one aspect of the solution of this disclosure, a terminal device determines that one or more CSI-RS signals are not received from a cell, and the terminal device is configured to perform CSI-RS-based measurements by monitoring at least one CSI-RS signal from the cell. Based on the determination that the one or more CSI-RS signals are not received, the terminal device performs operations related to the CSI-RS-based measurements based on at least one of: (i) SSB-based measurements from the cell, or (ii) whether the terminal device is aware of the DTX configuration of the cell. By using SSB-based measurements to determine CSI-RS measurement behavior, network energy saving is improved, and measurement time is saved. In this way, communication efficiency is improved. Example embodiments of this disclosure for performing operations related to CSI-RS-based measurements will be referenced below. Figure 2-8 Describe it.

[0046] Figure 2 A flowchart of a method 200 implemented at a terminal device according to some embodiments of the present disclosure is shown. For discussion purposes, reference will be made to... Figure 1A Method 200 is described from the perspective of terminal device 110. It should be understood that method 200 may also include additional boxes not shown and / or omit some boxes shown, and the scope of this disclosure is not limited in this respect.

[0047] In block 210, terminal device 110 determines that one or more CSI-RSs have not been received from the cell, and terminal device 110 is configured to perform CSI-RS-based measurements by monitoring at least one CSI-RS from the cell. In other words, terminal device 110 can determine whether one or more CSI-RSs have been received from the cell by monitoring at least one CSI-RS from the cell.

[0048] In some embodiments, the cell may be the serving cell or a neighboring cell of the terminal device 110. The DTX configuration may include the configuration of active and inactive periods in the cell DTX. Furthermore, the DTX configuration may also include the activation or deactivation of the cell DTX. In one example, the terminal device 110 may be aware of the DTX configurations of its serving cell and its neighboring cells. In another example, the terminal device 110 may be aware of the DTX configuration of its serving cell, but may not be aware of the DTX configuration of its neighboring cells. Alternatively, the terminal device 110 may be aware of the active and inactive periods in the cell DTX of its neighboring cells, but may not be aware of the DTX activation of its neighboring cells.

[0049] In box 220, based on the determination that one or more CSI-RS are not received, terminal device 110 performs an operation related to the CSI-RS-based measurement based on at least one of the following: (i) an SSB-based measurement from the cell, or (ii) whether terminal device 110 is aware of the cell's DTX configuration.

[0050] In some scenarios, terminal device 110 can be aware of the DTX configuration of the cell. Based on this DTX configuration, terminal device 110 can know that the cell is in a DTX inactive period and CSI-RS has not been transmitted. Therefore, terminal device 110 skips CSI-RS measurement and determines that CSI-RS is not received based on the cell's DTX configuration awareness. If terminal device 110 determines that one or more CSI-RS signals were not transmitted during the cell's DTX inactive period, terminal device 110 can perform operations related to the CSI-RS measurement based on the SSB-based measurement.

[0051] In some examples, CSI-RS-based measurements may include measurements of CSI reference signal received power (CSI-RSRP), CSI reference signal received quality (CSI-RSRQ), and / or CSI-SINR. Additionally, SSB-based measurements may include measurements of synchronization signal reference signal received power (SS-RSRP), SS-RSRQ, and / or SS-SINR.

[0052] In the DTX configuration, it is defined whether CSI-RS will be dropped or not transmitted during the inactive period of the cell's DTX. In one example, terminal device 110 is aware of the cell DTX patterns of the serving cell and neighboring cells, so terminal device 110 knows when CSI-RS will not be transmitted in all the cells it monitors or measures. Since SSB transmission is not affected by the cell DTX state, terminal device 110 can use SSB-based measurements (e.g., SS-RSRP) to determine how to handle lost CSI-RS (dropped due to cell DTX).

[0053] During inactive periods of cells known to terminal device 110 in its DTX mode, terminal device 110 can monitor SSBs in addition to CSI-RS, for example, when an associated SSB is configured for a CSI-RS-based measurement.

[0054] In some cases, if the measurement result based on SSB is higher than a first threshold, the terminal device 110 may perform the first operation. In some embodiments, if the change in the measurement result based on SSB is lower than a second threshold, the terminal device 110 may perform the first operation. In some embodiments, if the measurement result based on SSB is higher than the first threshold and the change in the measurement result based on SSB is lower than the second threshold, the terminal device 110 may perform the first operation.

[0055] For example, if terminal device 110 detects that the cell SS-RSRP is above a threshold and / or the SS-RSRP change is within another threshold, terminal device 110 can conclude that it is in the cell center and / or that it has not moved. Therefore, (discarded) CSI-RSRPs that were not transmitted during cell inactivity and are therefore unavailable for CSI-RSRP measurement may not significantly affect the filtered measurement.

[0056] The first operation may include or may be various steps or actions. For example, terminal device 110 may skip collecting at least one measurement sample of CSI-RS-based measurements during the inactive period of DTX in the cell. Alternatively or additionally, terminal device 110 may skip collecting at least one measurement sample of CSI-RS-based measurements during at least one of the configured CSI-RS measurement times. Alternatively or additionally, terminal device 110 may prevent the extension of the measurement period or measurement delay of CSI-RS-based measurements. Alternatively or additionally, terminal device 110 may derive an estimated measurement sample of CSI-RS-based measurements for the inactive period based on changes in the measurement results of SSB-based measurements during the inactive period and at least one previous measurement sample of CSI-RS-based measurements. Alternatively or additionally, terminal device 110 may derive an estimated measurement sample of CSI-RS-based measurements for the inactive period based on at least one measurement sample of CSI-RS-based measurements in a previous active period. Alternatively or additionally, terminal device 110 may derive estimated measurement samples of CSI-RS-based measurements for inactive periods based on at least one measurement sample of SSB-based measurements during inactive periods.

[0057] For example, the terminal device can skip collecting CSI-RS-based measurement samples during the current cell DTX inactive period. More specifically, the terminal device can apply the original measurement period, i.e., even though some samples are lost, there is no need to extend the period; that is, a smaller number of samples is sufficient. Alternatively, if the number of available samples is insufficient to ensure adequate accuracy, the UE can derive the estimated CSI-RSRP samples (for CSI-RS transmissions dropped during inactive periods) based on SS-RSRP changes in the corresponding window (e.g., inactive period) and past CSI-RSRP measurements. Furthermore, the terminal device can derive the estimated CSI-RSRP based on the measured SS-RSRP.

[0058] In some embodiments, if the measurement result of the SSB-based measurement is below a first threshold, the terminal device may perform a second operation. In some embodiments, if the change in the measurement result of the SSB-based measurement is above a second threshold, the terminal device may perform a second operation. In some embodiments, if the measurement result of the SSB-based measurement is below the first threshold and the change is above the second threshold, the terminal device may perform a second operation.

[0059] In some embodiments, the second operation may also include or may be various steps or actions. For example, terminal device 110 may acquire at least one additional measurement sample of CSI-RS-based measurements. Alternatively or additionally, terminal device 110 may extend the measurement period of CSI-RS-based measurements. Alternatively or additionally, terminal device 110 may fall back to SSB-based measurements without performing CSI-RS-based measurements. Alternatively or additionally, terminal device 110 may send a request to the network device serving the cell for transmitting at least one CSI-RS during inactive periods, or any combination of two or more of the above.

[0060] For example, if the terminal device determines that none of the following conditions are met: (i) SSB-based measurements from the cell, or (ii) whether the terminal device is aware of the cell's DTX configuration, then the terminal device needs to acquire additional CSI-RS measurement samples to meet the measurement requirements. The terminal device needs to attempt to acquire additional samples during the cell's active period. Alternatively, the measurement period can be extended accordingly. Furthermore, the terminal device can indicate to the network its need or preference for transmitting CSI-RS during inactive times.

[0061] Alternatively, at least one additional measurement sample of the CSI-RS-based measurement is acquired during the active period. Furthermore, the measurement period is extended to acquire a predetermined number of measurement samples of the CSI-RS-based measurement during the active period. In one example, the target has already been defined in the following specification as the UE acquiring (e.g.) 5 samples, so the same target can be applied when the measurement period is extended. Table 9.2.5.2-1: Measurement period (FR1) for gapless intra-frequency measurements Note 1: If different SMTC periodicities are configured for different cells, the required SMTC period is the period used by the identified cell.

[0062] If the period during which the terminal device does not receive CSI-RS from the cell is longer than a third threshold, the terminal device may fall back to SSB-based measurements without performing CSI-RS-based measurements. For example, if the SS-RSRP does not meet the following conditions: (i) SSB-based measurements from the cell, or (ii) whether the terminal device is aware that the DTX configuration of the cell is met, or if the period of CSI-RS loss is higher than the threshold, the terminal device may fall back to SS-RSRP measurements only. The UE may also indicate to the network, based on an assessment of the conditions, that CSI-RS-based measurements may not be performed.

[0063] In some scenarios, the terminal device is unaware of the cell's DTX configuration. If one or more CSI-RS signals are not received by the terminal device, SSB-based measurements can be performed. For example, the terminal device may know the cell DTX configuration of its serving cell but not the cell DTX configuration of its neighboring cells, so the UE is unaware that the CSI-RS was not sent by one or more neighboring cells. For neighboring cells, in addition to CSI-RS, the terminal device also monitors SSBs on the neighboring cells, for example, when configuring associated SSBs for CSI-RS-based measurements.

[0064] If the terminal device determines that there is a lack of signal power in one or more intended resources for receiving the one or more CSI-RS, the terminal device can determine that the one or more CSI-RS are not being received by the terminal device. For example, if a CSI-RS is not being received by the terminal device, the UE can determine that it has been discarded.

[0065] If the measurement result based on SSB is higher than a fourth threshold, the terminal device may perform the first operation. In some embodiments, if the change in the measurement result based on SSB is lower than a fifth threshold, the terminal device may perform the first operation. In some other embodiments, if the measurement result based on SSB is higher than a fourth threshold and the change in the measurement result based on SSB is lower than a fifth threshold, the terminal device may perform the first operation.

[0066] For example, the terminal device can evaluate the above conditions based on SS-RSRP measurements. The terminal device can determine that there is no sudden change in SS-RSRP within the corresponding window (based on an incremental threshold). If CSI-RS is not received, the UE can assume that cell DTX is active in a neighboring cell and that the neighboring cell is in the inactive period of cell DTX. The UE can then follow the assumption that the terminal device is aware of the cell's DTX configuration. Measurement samples on CSI-RS will not be used for measurement filtering.

[0067] If the SSB-based measurement result is below a fourth threshold, the terminal device can fall back to SSB-based measurement without performing CSI-RS-based measurement. In some embodiments, if the change is above a fifth threshold, the terminal device can fall back to SSB-based measurement without performing CSI-RS-based measurement. In some embodiments, if the SSB-based measurement result is below a fourth threshold and the change is above a fifth threshold, the terminal device can fall back to SSB-based measurement without performing CSI-RS-based measurement. For example, if the terminal device observes a sudden change in SS-RSRP in the corresponding window and does not receive the expected CSI-RSRP, the terminal device assumes that CSI-RS was sent but not received due to other radio problems, i.e., cell DTX is not activated, and it falls back to SSB-based measurement or reports the CSI-RS-based measurement result as measured.

[0068] The terminal device can receive configuration information based on CSI-RS measurements from the network equipment of the serving cell providing the terminal device. This configuration information includes at least one of the following: a first threshold, a second threshold, a third threshold, a fourth threshold, or a fifth threshold. In some embodiments, the first threshold, the second threshold, the third threshold, the fourth threshold, the fifth threshold, or any combination of two or more of the above may be predetermined. For example, the thresholds may be configured by the network or predefined as default values.

[0069] In some implementations, the SSB in one or more SSBs may be indicated by configuration information based on CSI-RS measurements as an associated SSB of the CSI-RS in one or more CSI-RS. In some embodiments, the SSB may be quasi-co-located with the CSI-RS. In some embodiments, the SSB and the CSI-RS may be in the same Transport Configuration Indication (TCI) state. For example, the measured SSB should be an associated SSB of the CSI-RS-ResourceConfigMobility information element, an SSB with a QCL relationship to the CSI-RS to be measured, or an SSB in the same TCI state of the CSI-RS resource.

[0070] Typically, a terminal device can determine that CSI-RS is not being transmitted based on indications from the serving cell or a target neighbor cell. Alternatively, the terminal device can determine that CSI-RS is not being transmitted based on determining a lack of signal power in the expected resources, while also determining that the SSB from the same cell is available. By determining that the SSB is available, the terminal device can determine that it is not in deep fading / too far from the target cell, meaning that the terminal device should also be able to receive CSI-RS. The terminal device can derive an estimated CSI-RSRP sample based on the measured SS-RSRP. The terminal device needs to consider that the SSB and CSI-RS are measured on different time and frequency resources, that they are transmitted or received using potentially different beam patterns (wide or narrow beams), and that the transmit power may differ. Furthermore, the terminal device can also rely on past CSI-RS measurements to obtain the CSI-RSRP. For example, if the change or absolute level exceeds a certain threshold before the cell DTX inactivity period, the terminal device can be allowed to omit that sample and instead estimate the sample based on past CSI and / or SSB measurements.

[0071] By using SSB-based measurements to determine CSI-RS measurement behavior, the UE can save energy and time because it will not always be forced to extend the measurement period if channel conditions are good. Embodiments of this disclosure enable the network to configure the UE so that measurement performance is maintained even though CSI-RS is dropped during cell DTX inactivity periods.

[0072] Figure 3 An example procedure for a CSI-RS-based measurement according to some embodiments of this disclosure is shown. Procedure 300 may involve UE 301 and gNB 302. For discussion purposes, reference will be made to... Figure 1A Describe process 300. Therefore, Figure 3 UE 301 in the text can be Figure 1A Example of terminal device 110 in the middle, Figure 3 gNB 302 in the text can be Figure 1AExamples of network device 120 or network device 130.

[0073] In procedure 300, at 305, gNB 302 configures the cell DTX settings and sends them to UE 301. At 310, gNB 302 sends CSI-RS configuration to the UE, and the CSI-RS configuration includes one or more thresholds for processing CSI-RS during cell inactivity or non-active periods. At 315, cell DTX is activated, and UE 301 is aware that it may not receive CSI-RS during inactive periods and has the ability to detect this situation.

[0074] In one example, at 320, gNB 302 sends CSI-RS and SSB to UE 301. Accordingly, UE 301 monitors the periodically configured CSI-RS and SSB. At 325, UE 301 performs threshold assessment and SS-RSRP measurement.

[0075] In 330 and 335, if the measured SS-RSRP is greater than threshold 1 or its variation is within threshold 2, the UE estimates the CSI-RSRP based on the SS-RSRP variation and past CSI-RSRP during cell DTX inactivity. Additionally or alternatively, methods such as... Figure 2 Other options included in the first operation mentioned above.

[0076] In another example, at 340, UE 301 monitors CSI-RS and SSB. At 345, UE 301 performs threshold assessment and SS-RSRP measurement. At 350 and 355, if the measured SS-RSRP is less than threshold 1 or the SS-RSRP change exceeds threshold 2, the UE falls back to SS-RSRP measurement. Alternatively or additionally, methods such as... Figure 2 Other options included in the second operation mentioned above.

[0077] Figure 4 Example procedures for CSI-RS-based measurements according to some embodiments of this disclosure are shown. Procedure 400 may involve UE 401, gNB 402, and ngNB 403. For discussion purposes, reference will be made to... Figure 1A Describe process 400. Therefore, Figure 4 UE 401 in the context can be Figure 1A Example of terminal device 110 in the middle, Figure 4 gNB 402 in the text can be Figure 1A Example of network device 120 in the example, and Figure 4 In this context, ngNB 403 (hereinafter also referred to as neighbor gNB 403) can be... Figure 1A Example of network device 130 in the example.

[0078] In procedure 400, at 405, gNB 402 configures the cell DTX settings and sends them to UE 401. At 410, gNB 402 sends CSI-RS configuration to UE 401, and the CSI-RS configuration includes one or more thresholds for processing CSI-RS during cell inactivity. At 415, cell DTX is activated, UE 401 is aware that it may not receive CSI-RS, and UE 401 has the ability to detect this situation.

[0079] In one example, at 420, gNB 402 sends CSI-RS and SSB to UE 401. Neighbor gNB 403 sends periodic CSI-RS to the UE during cell activity time, but does not send CSI-RS during inactive time (unbeknownst to UE 401). Furthermore, SSB is still sent by neighbor gNB 403 during inactive time.

[0080] In steps 425 and 430, if CSI-RS is not received by UE 401, UE 401 monitors SSB. In step 435, UE 401 evaluates SS-RSRP and compares it to certain thresholds. In steps 440 and 445, if the measured SS-RSRP is greater than a threshold or its variation is within a specific threshold range, UE 401 can assume inactivity of cell DTX and follow the first operation to estimate CSI-RSRP. UE 401 can estimate CSI-RSRP based on changes in SS-RSRP and past CSI-RSRP measurements.

[0081] In another example, at 450, UE 401 monitors the periodically configured CSI-RS and SSB. At 455, UE 401 cannot detect CSI-RS. At 460, UE 401 monitors CSI-RS and SSB. At 465, UE 401 evaluates the SS-RSRP and compares it to certain thresholds. At 470 and 475, if either of the two SS-RSRP conditions is not met, or if both of the two SS-RSRP conditions are not met, UE 401 assumes that the CSI-RS was transmitted but not received due to other radio problems, and it falls back to a traditional procedure (e.g., beam scanning) for this situation.

[0082] Figure 5 An example flowchart of CSI-RS-based measurements according to some embodiments of this disclosure is shown. Reference will be made to... Figure 1A The process 500 is described from the perspective of terminal device 110. Terminal device 110 is aware of the DTX configuration of the cell.

[0083] In block 505, terminal device 110 measures the SS-RSRP of the cell. In block 510, terminal device 110 determines whether at least one of the following conditions is met: the SS-RSRP is greater than threshold 1 or the SS-RSRP change is within threshold 2. If at least one of the conditions is met, terminal device 110 may perform at least one operation in blocks 515, 520, 525, and 530. If no condition is met, terminal device 110 may perform at least one operation in blocks 535, 540, 545, and 550.

[0084] Figure 6 An example flowchart of CSI-RS-based measurements according to some embodiments of this disclosure is shown. Reference will be made to... Figure 1A The process 600 is described from the perspective of terminal device 110. Terminal device 110 is unaware of the DTX configuration of the cell.

[0085] In box 605, terminal device 110 measures at least one of the SS-RSRP or CSI-RSRP of the cell. In box 610, terminal device 110 determines whether at least one of the following conditions is met: the SS-RSRP is within a certain threshold or the SS-RSRP change is within a threshold and there is no sudden threshold change in SS-RSRP. In box 615, if at least one of the conditions is met, terminal device 110 can determine that the cell is in a cell DTX inactive period. In box 620, terminal device 110 can follow a first operation. In box 625, if none of the conditions are met, terminal device 110 can determine that CSI-RS was sent but not received by terminal device 110.

[0086] In some embodiments, an apparatus (e.g., terminal device 110) capable of performing any of the methods in method 200 is provided. The apparatus may include components for performing the corresponding steps of method 200. These components may be implemented in any suitable form. For example, these components may be implemented in a circuit system or a software module.

[0087] In some embodiments, the apparatus includes: components for determining at a terminal device that one or more Channel State Information (CSI) Reference Signals (RS) have not been received from a cell, wherein the terminal device is configured to perform CSI-RS-based measurements by monitoring at least one CSI-RS from the cell; and components for performing operations related to the CSI-RS-based measurements based on determining that the one or more CSI-RS have not been received, based on at least one of: (i) measurements based on Synchronization Signal / Physical Broadcast Channel (PBCH) Blocks (SSBs) from the cell, or (ii) whether the terminal device is aware of the cell’s Discontinuous Transmission (DTX) configuration.

[0088] In some embodiments, the terminal device may be aware of the DTX configuration of the cell; and based on the determination that one or more CSI-RS were not transmitted during the inactive period of the cell's DTX, operations related to the CSI-RS-based measurement are performed based on the SSB-based measurement.

[0089] In some embodiments, the components for performing operations related to the CSI-RS-based measurement may include: components for performing a first operation based on determining at least one of the following: (i) the measurement result of the SSB-based measurement is higher than a first threshold, or (ii) the change in the measurement result of the SSB-based measurement is lower than a second threshold; or components for performing a second operation based on determining at least one of the following: (i) the measurement result of the SSB-based measurement is lower than the first threshold, or (ii) the change is higher than the second threshold.

[0090] In some embodiments, the first operation may include at least one of the following: skipping the collection of at least one measurement sample of the CSI-RS-based measurement during the inactive period of the cell's DTX; skipping the collection of at least one measurement sample of the CSI-RS-based measurement in at least one of the configured CSI-RS timings; preventing the extension of the measurement period of the CSI-RS-based measurement; deriving an estimated measurement sample of the CSI-RS-based measurement for the inactive period based on changes in the measurement results of the SSB-based measurement during the inactive period and at least one previous measurement sample of the CSI-RS-based measurement; deriving an estimated measurement sample of the CSI-RS-based measurement for the inactive period based on at least one measurement sample of the CSI-RS-based measurement in a previous active period; or deriving an estimated measurement sample of the CSI-RS-based measurement for the inactive period based on at least one measurement sample of the SSB-based measurement during the inactive period.

[0091] In some embodiments, the second operation may include at least one of the following: acquiring at least one additional measurement sample of the CSI-RS-based measurement; extending the measurement period of the CSI-RS-based measurement; reverting to the SSB-based measurement without performing the CSI-RS-based measurement; or sending a request to the network device serving the cell for transmitting at least one CSI-RS during an inactive period.

[0092] In some embodiments, at least one additional measurement sample of the CSI-RS-based measurement may be acquired during an active period; or the measurement period may be extended to acquire a predetermined number of measurement samples of the CSI-RS-based measurement.

[0093] In some embodiments, the apparatus may include: a component for falling back to the SSB-based measurement without performing the CSI-RS-based measurement based on determining that the period during which the terminal device has not received CSI-RS from the cell is longer than a third threshold.

[0094] In some embodiments, the terminal device may be unaware of the cell's DTX configuration; and the SSB-based measurement may be performed based on the determination that one or more CSI-RS are not received by the terminal device.

[0095] In some embodiments, the components for determining that the one or more CSI-RS are not received by the terminal device may include: components for determining that there is a lack of signal power in one or more expected resources for receiving the one or more CSI-RS.

[0096] In some embodiments, the components for performing operations related to the CSI-RS-based measurement may include: components for performing a first operation based on determining at least one of the following: (i) the measurement result of the SSB-based measurement is higher than a fourth threshold, or (ii) the change in the measurement result of the SSB-based measurement is lower than a fifth threshold; or components for reverting to the SSB-based measurement without performing the CSI-RS-based measurement based on determining at least one of the following: (i) the measurement result of the SSB-based measurement is lower than a fourth threshold, or (ii) the change is higher than a fifth threshold.

[0097] In some embodiments, the apparatus may include: a component for receiving configuration information of the CSI-RS-based measurement from a network device providing the serving cell of the terminal device, wherein the configuration information includes at least one of the following: a first threshold, a second threshold, a third threshold, a fourth threshold, or a fifth threshold.

[0098] In some embodiments, at least one of the first threshold, the second threshold, the third threshold, the fourth threshold, or the fifth threshold may be predetermined.

[0099] In some embodiments, the SSB in the one or more SSBs may be indicated by the configuration information based on the CSI-RS measurement as the associated SSB of the one or more CSI-RS; the SSB may be quasi-co-located with the CSI-RS; or the SSB and the CSI-RS may be in the same Transmission Configuration Indication (TCI) state.

[0100] In some embodiments, the CSI-RS based measurement may include the measurement of CSI reference signal received power (CSI-RSRP); or the SSB based measurement may include the measurement of synchronization signal reference signal received power (SS-RSRP). In some embodiments, the cell may be the serving cell or a neighboring cell of the terminal device.

[0101] In some embodiments, the apparatus may further include components for performing other steps in some embodiments of method 200. In some embodiments, these components include at least one processor; and at least one memory, including computer program code, the at least one memory and the computer program code being configured, together with the at least one processor, to cause the apparatus to perform the steps.

[0102] Figure 7 This is a simplified block diagram of a device 700 suitable for implementing embodiments of the present disclosure. Device 700 can be provided to implement a communication device, such as... Figure 1A The terminal device 110 shown is illustrated. As shown, device 700 includes one or more processors 710 and one or more communication modules 740 coupled to the processors 710. Device 700 may also include one or more memories 720 coupled to the processors 710.

[0103] The communication module 740 can be used for bidirectional communication. The communication module 740 has at least one antenna to facilitate communication. The communication interface can represent any interface necessary for communication with other network elements.

[0104] Processor 710 can be of any type suitable for a local technology network, and by way of non-limiting example, can include one or more of the following: general-purpose computer, special-purpose computer, microprocessor, digital signal processor (DSP), and processor based on a multi-core processor architecture. Device 700 can have multiple processors, such as application-specific integrated circuit chips that are time-dependent on a clock synchronized with the main processor.

[0105] Memory 720 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 724, electrically programmable read-only memory (EPROM), flash memory, hard disk, optical disc (CD), digital video disc (DVD), and other magnetic and / or optical storage. Examples of volatile memories include, but are not limited to, random access memory (RAM) 722 and other volatile memories that do not persist during power-off periods.

[0106] Computer program 730 includes computer-executable instructions that are executed by an associated processor 710. Program 730 may be stored in ROM 724. Processor 710 may perform any suitable actions and processes by loading program 730 into RAM 722.

[0107] The embodiments of this disclosure can be implemented via program 730, enabling device 700 to execute reference... Figures 2 to 6 Any process discussed in this disclosure. Embodiments of this disclosure may also be implemented by hardware or a combination of software and hardware.

[0108] In some embodiments, program 730 may be tangibly contained in a computer-readable medium, which may be included in device 700 (such as in memory 720) or in other storage devices accessible to device 700. Device 700 may load program 730 from the computer-readable medium into RAM 722 for execution. The computer-readable medium may include any type of tangible non-volatile storage, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. Figure 8 An example of a computer-readable medium 800 in the form of a CD or DVD is shown. A program 730 is stored on the computer-readable medium.

[0109] Generally, the various embodiments of this disclosure can be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects can be implemented in hardware, while others can be implemented in firmware or software, which can be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of this disclosure are shown and described as block diagrams, flowcharts, or using certain other graphical representations, it should be understood that the blocks, apparatuses, systems, techniques, or methods described herein can be implemented as non-limiting examples in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0110] This disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, which execute in a device on a target real or virtual processor to perform the functions described above. Figure 2 Method 200 is described. Typically, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc., that perform specific tasks or implement specific abstract data types. The functionality of a program module can be combined or split among program modules as needed in various embodiments. The machine-executable instructions of a program module can execute on a local or distributed device. In a distributed device, program modules can reside on local and remote storage media.

[0111] Program code used to perform the methods of this disclosure may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that, when executed by the processor or controller, the program code enables the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a machine, partially on a machine, as a stand-alone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0112] In the context of this disclosure, computer program code or related data may be carried by any suitable carrier to enable a device, apparatus, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer-readable media, etc.

[0113] Computer-readable media can be computer-readable signal media or computer-readable storage media. Computer-readable media can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination thereof. More specific examples of computer-readable storage media will include electrical connections having one or more wires, portable computer floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable optical disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. As used herein, the term “non-transient” is a limitation on the medium itself (i.e., tangible, not a signal), not a limitation on the persistence of data storage (e.g., RAM and ROM).

[0114] Furthermore, although the operations are depicted in a specific order, this should not be construed as requiring these operations to be performed in the specific order shown or sequentially, or to perform all the operations shown, in order to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the foregoing discussion, these should not be construed as limiting the scope of this disclosure, but rather as a description of features that may be specific to particular embodiments. Certain features described in the context of a single embodiment may also be implemented in combination in a single embodiment. Conversely, the various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0115] Although this disclosure has been described in language specific to structural features and / or methodological behavior, it should be understood that this disclosure as defined in the appended claims is not necessarily limited to the specific features or behaviors described above. Rather, the specific features and behaviors described above are disclosed as exemplary forms of implementing the claims.

Claims

1. A terminal device, comprising: At least one processor; as well as At least one memory stores instructions that, when executed by the at least one processor, cause the terminal device to at least: Determining that one or more Channel State Information (CSI) Reference Signals (RS) are not received from the cell, wherein the terminal device is configured to perform CSI-RS-based measurements by monitoring at least one CSI-RS from the cell; as well as Based on the determination that one or more CSI-RS are not received, the operation related to the CSI-RS-based measurement is performed based on at least one of the following: (i) measurement of the Synchronization Signal / Physical Broadcast Channel PBCH Block SSB from the cell, or (ii) whether the terminal device is aware of the cell's Discontinuous Transmission (DTX) configuration.

2. The terminal device according to claim 1, wherein: The terminal device is aware of the DTX configuration of the cell; as well as Based on the determination that one or more CSI-RS were not transmitted during the inactive period of the DTX in the cell, the operation related to the CSI-RS-based measurement is performed based on the SSB-based measurement.

3. The terminal device of claim 2, wherein the terminal device is configured to perform the operation related to the CSI-RS-based measurement by: The first operation is performed based on determining at least one of the following: (i) the measurement result of the SSB-based measurement is higher than a first threshold, or (ii) the change in the measurement result of the SSB-based measurement is lower than a second threshold; or The second operation is performed based on determining at least one of the following: (i) the measurement result of the SSB-based measurement is lower than the first threshold, or (ii) the change is higher than the second threshold.

4. The terminal device according to claim 3, wherein the first operation includes at least one of the following: During the inactive period of the DTX in the cell, at least one measurement sample of the CSI-RS-based measurement is skipped from being collected; Skip the collection of at least one measurement sample of CSI-RS-based measurements during at least one of the configured CSI-RS timings; To prevent the measurement period of the CSI-RS-based measurement from being prolonged; Based on the changes in the measurement results of the SSB-based measurement during the inactive period, and at least one previous measurement sample of the CSI-RS-based measurement, an estimated measurement sample of the CSI-RS-based measurement for the inactive period is derived. Based on at least one measurement sample of the CSI-RS-based measurement during the previous active period, derive an estimated measurement sample of the CSI-RS-based measurement for the inactive period; or Based on at least one measurement sample of the SSB-based measurement during the inactive period, an estimated measurement sample of the CSI-RS-based measurement for the inactive period is derived.

5. The terminal device according to claim 3 or 4, wherein the second operation includes at least one of the following: Obtain at least one additional measurement sample of the CSI-RS-based measurement; Extend the measurement period of the CSI-RS-based measurement; Revert to the SSB-based measurement without performing the CSI-RS-based measurement; or Send a request to the network device serving the cell for transmitting at least one CSI-RS during the inactive period.

6. The terminal device according to claim 5, wherein one of the following: The at least one additional measurement sample of the CSI-RS-based measurement was acquired during the activity period; or The measurement period is extended to obtain a predetermined number of measurement examples of the CSI-RS-based measurements.

7. The terminal device according to any one of claims 1 to 6, wherein the terminal device is further configured to: Based on the determination that the period during which the terminal device has not received CSI-RS from the cell is longer than a third threshold, the measurement is reverted to the SSB-based measurement without performing the CSI-RS-based measurement.

8. The terminal device according to claim 1, wherein: The terminal device is unaware of the DTX configuration of the cell; and The SSB-based measurement is performed based on determining that one or more CSI-RS are not received by the terminal device.

9. The terminal device of claim 8, wherein the terminal device is configured to determine that the one or more CSI-RS are not received by the terminal device by: It was determined that there was a lack of signal power in one or more intended resources for receiving the one or more CSI-RS.

10. The terminal device according to claim 8 or 9, wherein the terminal device is configured to perform the operation related to the CSI-RS-based measurement by: The first operation is performed based on determining at least one of the following: (i) the measurement result of the SSB-based measurement is higher than a fourth threshold, or (ii) the change in the measurement result of the SSB-based measurement is lower than a fifth threshold; or A fallback to the SSB-based measurement is made without performing the CSI-RS-based measurement based on at least one of the following: (i) the measurement result of the SSB-based measurement is below the fourth threshold, or (ii) the change is above the fifth threshold.

11. The terminal device according to any one of claims 3 to 7 and 10, wherein the terminal device is further configured to: The network device of the serving cell providing the terminal device receives configuration information of the CSI-RS-based measurement, wherein the configuration information includes at least one of the following: the first threshold, the second threshold, the third threshold, the fourth threshold, or the fifth threshold.

12. The terminal device according to any one of claims 3 to 7 and 10, wherein at least one of the first threshold, the second threshold, the third threshold, the fourth threshold, or the fifth threshold is predetermined.

13. The terminal device according to any one of claims 1 to 12, wherein at least one of the following: The SSB in the one or more SSBs is indicated by the configuration information of the CSI-RS-based measurement as the associated SSB of the one or more CSI-RSs; The SSB is quasi-co-located with the CSI-RS; or The SSB and the CSI-RS are in the same Transmission Configuration Indication (TCI) state.

14. The terminal device according to any one of claims 1 to 13, wherein at least one of the following: The CSI-RS-based measurement includes the measurement of the CSI reference signal received power (CSI-RSRP); or The SSB-based measurements include the measurement of the synchronization reference signal received power (SS-RSRP).

15. The terminal device according to any one of claims 1 to 14, wherein the cell is the serving cell or a neighboring cell of the terminal device.

16. A method comprising: At a terminal device, it is determined that one or more Channel State Information (CSI) Reference Signals (RS) are not received from the cell, wherein the terminal device is configured to perform CSI-RS-based measurements by monitoring at least one CSI-RS from the cell; as well as Based on the determination that one or more CSI-RS are not received, the operation related to the CSI-RS-based measurement is performed based on at least one of the following: (i) measurement of the Synchronization Signal / Physical Broadcast Channel PBCH Block SSB from the cell, or (ii) whether the terminal device is aware of the cell's Discontinuous Transmission (DTX) configuration.

17. An apparatus comprising: Components for determining at a terminal device that one or more Channel State Information (CSI) Reference Signals (RS) have not been received from a cell, wherein the terminal device is configured to perform CSI-RS-based measurements by monitoring at least one CSI-RS from the cell; as well as The component is used to perform operations related to the CSI-RS-based measurement based on at least one of the following: (i) a measurement of the Synchronization Signal / Physical Broadcast Channel (PBCH) block SSB from the cell, or (ii) whether the terminal device is aware of the cell's Discontinuous Transmission (DTX) configuration.

18. A non-transitory computer-readable medium comprising program instructions that, when executed by a device, cause the device to perform at least the method according to claim 16.

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