Cell / beam measurements in a non-terrestrial network (NTN) with cell / beam discontinuous transmission (DTX)

Abstract

This disclosure provides systems, methods, and apparatuses for managing cell or beam measurements for a non-terrestrial network (NTN) that implements a connected discontinuous reception (c-DRX) configuration or cell / beam discontinuous transmission (DTX) / DRX. An NTN node 101 (such as satellite 104) provides a c-DRX configuration to inform a user equipment (UE) 102 of configured OFF periods for a first cell / beam of the NTN during which the NTN does not transmit downlink reference signals. The UE can suspend 170 (e.g., stop, refrain, pause) cell / beam operations during the OFF period. Some aspects align radio link monitoring (RLM) and beam failure detection (BFD) operations with ON periods of the cell / beam DTX / DRX configuration and disable RLM / BFD operations during the OFF periods. In some aspects, a NTN can provide a cell / beam DTX / DRX configuration for a neighboring cell and the UE can suspend and resume neighboring cell measurement based on OFF / ON periods, respectively, of the neighboring cell / beam.

Description

CELL / BEAM MEASUREMENTS IN A NON-TERRESTRIAL NETWORK (NTN) WITH CELL / BEAM DISCONTINUOUS TRANSMISSION (DTX)RELATED APPLICATION

[0001] This application claims the priority benefit of U.S. Provisional Patent Application Serial No. 63 / 676,609, filed July 29, 2024, and entitled “CELL / BEAM MEASUREMENTS IN A NONTERRESTRIAL NETWORK (NTN) WITH CELL / BEAM DISCONTINUOUS TRANSMISSION (DTX),” the entire contents of which are hereby incorporated by reference herein.TECHNICAL FIELD

[0002] This disclosure relates generally to wireless communication and some aspects relate to user equipment (UE) measurements for radio link monitoring (RLM), beam failure detection (BFD), and mobility in a non-terrestrial network (NTN) using beam / cell discontinuous transmission (DTX) operation.BACKGROUND

[0003] This background description is provided for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[0004] A wireless communication system includes one or more network entities (such as a base station) enabling communication for a mobile communication device (referred to as a user equipment (UE)). Each base station operates one or more cells to provide coverage for the UE. Existing wireless communication systems and network selection techniques are based primarily on legacy terrestrial networks. However, the 3rdGeneration Partnership Project (3 GPP) organization has proposed to extend 5thGeneration (5G) communications to non-terrestrial networks (NTNs) with 5G new radio (NR) technologies, or with the Long-Term -Evolution (LTE) technologies tailored for the Narrowband Internet-of-Things (NB-IoT) or the enhanced Machine Type Communication (eMTC) technologies. A non-terrestrial network (NTN) refers to a network, or segment of networks, using radio frequency (RF) resources on board an NTN node. Example NTN nodes include spaceborne vehicles or airborne vehicles. Airborne vehicles caninclude unmanned aircraft systems (UAS), High-Altitude Platform Systems (HAPS), balloons, dirigibles, winged vehicles such as airplanes or drones, among other examples. Spaceborne vehicles can include a Geostationary Earth Orbit (GEO) satellite (sometimes also referred to as a geosynchronous orbit (GSO) satellite), a Low Earth Orbit (LEO) satellite, a Medium Earth Orbit (MEO) satellite, or a Highly Elliptical Orbit (HEO) satellite, among other examples. In some implementations, NTN nodes can form constellations. For simplicity, the discussion below refers to all NTN nodes (including spaceborne vehicles and airborne vehicles) as satellites; and the terms “satellite” and “NTN node” can be used interchangeably. A satellite can use a transparent payload implementation or a regenerative payload implementation. In the transparent payload implementation, the satellite performs RF signal processing and transmission based on a waveform signal provided by a ground base station. In the regenerative payload implementation, the satellite includes onboard equipment for RF processing and transmission as well as modulation / demodulation and coding / decoding, effectively implementing most of the functions of a base station using the onboard equipment.

[0005] A satellite directs radio frequency (RF) transmission towards a specific direction, creating a “beam” of focused energy for a beam footprint, thereby improving signal quality and increasing network performance for UEs within the beam footprint. The footprint of a beam typically has an elliptic shape depending on the on-board antenna configuration and the elevation angle. In some implementations, a satellite can generate several beams within a field of view from the satellite. By projecting multiple beams toward an area, the satellite might expand the cell coverage available for UEs in the footprint of the various beams. The satellite may activate (i.e., turns on) or deactivate (i.e., turns off) a set of the available beams according to a discontinuous transmission (DTX) configuration. In some implementations, the DTX configuration reduces power consumption of the satellite and / or enables the satellite to operate multiple beams despite limited feeder link bandwidth.BRIEF SUMMARY

[0006] The systems, methods, and apparatuses of this disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0007] An innovative aspect of the subject matter described in this disclosure can be implemented as a method for wireless communication by a user equipment (UE). The method includes the UE receiving, from a first non-terrestrial network (NTN) node, a cell or beam discontinuous transmission (DTX) or discontinuous reception (DRX) configuration (cell / beamDTX / DRX configuration) indicating an OFF period for a first cell or beam (first cell / beam) of the first NTN node. The method includes the UE suspending measurements of downlink reference signals for the first cell / beam during the OFF period. The method includes the UE resuming measurements of the downlink reference signals for the first cell / beam during an ON period following the OFF period.

[0008] An innovative aspect of the subject matter described in this disclosure can be implemented as a method for wireless communication by a UE. The method includes the UE receiving, from a first NTN node, a neighboring cell / beam DTX / DRX configuration for a neighboring cell / beam, the neighboring cell / beam DTX / DRX configuration indicating ON periods and OFF periods of the neighboring cell / beam. The method includes the UE suspending measurements of downlink reference signals for the neighboring cell / beam during the OFF periods of the neighboring cell / beam. The method includes the UE resuming measurements of the downlink reference signals for the neighboring cell / beam during the ON periods.

[0009] An innovative aspect of the subject matter described in this disclosure can be implemented as a method for wireless communication by an NTN node. The method includes the NTN node transmitting, to a UE, a cell / beam DTX / DRX configuration indicating an OFF period for a first cell or beam (first cell / beam) of the NTN node. The method includes the NTN node causing the UE to suspend measurements of downlink reference signals for the first cell / beam during the OFF period.

[0010] Another innovative aspect of the subject matter described in this disclosure can be implemented as an apparatus that includes a communication unit and a processing system configured to control the communication unit to implement any one of the above-referenced methods.

[0011] Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Like reference numbers and designations in the various drawings indicate like elements. Note that the relative dimensions of the figures may not be drawn to scale. To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

[0013] FIG. 1 shows an example wireless communication system in which a user equipment (UE) performs cell / beam measurements of a cell / beam from a non-terrestrial network (NTN) node based on a cell / beam discontinuous transmission (DTX) or discontinuous reception (DRX) configuration.

[0014] FIG. 2A shows an example wireless communication system implementing an NTN base station (BS) connecting to a satellite via an NTN gateway using a transparent payload implementation.

[0015] FIG. 2B shows an example wireless communication system implementing an NTN BS onboard a satellite using a regenerative payload implementation.

[0016] FIG. 3A shows an example cell / beam DTX / DRX operation for an NTN node operating multiple beams.

[0017] FIG. 3B shows example patterns for cell / beam DTX / DRX operation.

[0018] FIG. 3C shows a UE potentially in coverage of multiple beams at various times based on overlapping beams.

[0019] FIG. 4A shows example states for cell / beam DTX / DRX operation.

[0020] FIG. 4B shows example parameters for a cell / beam DTX / DRX configuration.

[0021] FIG. 4C shows an example technique for configuring and activating cell / beam DTX / DRX configurations.

[0022] FIG. 5 shows a messaging diagram and operations of a UE coordinating cell / beam measurements based on a cell / beam DTX / DRX configuration.

[0023] FIG. 6 shows a messaging diagram of an example scenario in which a UE in the connected state determines when to suspend and when to resume radio link monitoring (RLM) and / or the beam failure detection (BFD) measurements based on the cell / beam DTX / DRX configuration(s).

[0024] FIG. 7 shows a messaging diagram of an example scenario in which a UE in the connected state determines when to measure or monitor the reference signal (RS) resources configured for RLM / BFD based on the UE connected discontinuous reception (c-DRX) configuration aligning with the cell / beam DTX / DRX configuration.

[0025] FIG. 8 shows a messaging diagram of an example scenario in which a UE in the connected state determines when to suspend and when to resume the serving cell measurement based on the cell or the beam DTX / DRX configuration(s).

[0026] FIG. 9 shows a messaging diagram of an example scenario in which a UE in the connected state determines when to perform the serving cell measurement based on the UE c- DRX configuration aligning with the cell / beam DTX / DRX configuration.

[0027] FIG. 10A shows a messaging diagram of an example scenario in which a UE in the connected state determines when to measure a neighboring cell based on the cell / beam DTX / DRX configuration(s) included in the measurement object configuration for the neighboring cell.

[0028] FIG. 10B shows a messaging diagram of an example scenario in which a UE in the connected state determines when to measure a neighboring cell based on the cell / beam DTX / DRX configuration(s) of the neighboring cell included in the system information.

[0029] FIG. 11 shows a messaging diagram of an example scenario in which a UE in the idle state determines when to measure a neighboring cell based on the cell / beam DTX / DRX configuration(s) of the neighboring cell included in the system information.

[0030] FIG. 12 shows a flow diagram showing example operations of a UE, in the connected state, managing RLM / BFD measurements based on the cell / beam DTX / DRX configuration(s).

[0031] FIG. 13 shows a flow diagram showing example operations of a UE, in the connected state, managing the RLM / BFD measurements based on the cell / beam DTX / DRX configuration(s) including a status indication for the OFF period.

[0032] FIG. 14 shows a flow diagram showing example operations of a UE, in the connected state, managing when to monitor the RS resources configured for the RLM / BFD based on the UE c-DRX configuration aligning with the cell / beam DTX / DRX configuration.

[0033] FIG. 15 shows a flow diagram showing example operations of a UE, in the connected state, managing when to suspend and when to resume the serving cell measurement based on the cell / beam DTX / DRX configuration(s).

[0034] FIG. 16 shows a flow diagram showing example operations of a UE, in the connected state, managing when to perform the serving cell measurement based on the UE c-DRX configuration aligning with the cell or beam DTX / DRX configuration.

[0035] FIG. 17A shows a flow diagram showing example operations of a UE, in the connected state, managing when to measure a neighboring cell based on the cell / beam DTX / DRX configuration(s) included in the measurement object configuration for the neighboring cell.

[0036] FIG. 17B shows a flow diagram showing example operations of a UE, in the connected state, managing when to measure a neighboring cell based on the cell / beam DTX / DRX configuration of the neighboring cell included in the system information.

[0037] FIG. 18 shows a flow diagram showing example operations of a BS informing a UE of the DTX / DRX configuration of the serving beam and optionally configuring the UE with a c- DRX configuration aligning with the DTX / DRX configuration of the serving beam.

[0038] FIG. 19A shows a flow diagram showing example operations of a BS for informing the UE of the DTX / DRX configuration of a neighboring cell via the measurement object configuration.

[0039] FIG. 19B shows a flow diagram showing example operations of a BS for informing the UE of the DTX / DRX configuration of a neighboring cell via the measurement object configuration and the system information.

[0040] FIG. 20A shows an example control plane protocol stack for a regenerative NTN architecture in accordance with aspects of this disclosure.

[0041] FIG. 20B shows an example control plane protocol stack for a transparent NTN architecture in accordance with aspects of this disclosure.

[0042] FIG. 21 shows a block diagram of an example wireless communication system showing hardware features and communication interfaces.DETAILED DESCRIPTION

[0043] The following description is directed to certain implementations for the purpose of describing innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. Some of the examples in this disclosure are based on wireless communication according to the 3rdGeneration Partnership Project (3 GPP) wireless standards, such as the 4th generation (4G) Long Term Evolution (LTE) and 5thgeneration (5G) New Radio (NR) standards. However, the described implementations can be implemented in any device, system, or network that is capable of transmitting and receiving radio frequency signals according to any of the wireless communication standards, including any of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 or 802.16 wireless standards, or other known signals that are used to communicate within a wireless, cellular, or internet of things (loT) network, such as a system utilizing 4G, 5G, 6th generation (6G), WLAN (e g., WiFi), or future radio technology.

[0044] A non-terrestrial network (NTN) node (e.g., a satellite) may operate multiple beams to enhance the downlink coverage (i.e., to improve the satellite footprint). For example, a satellite can project more than one beam within a footprint area on Earth. A satellite might not continuously project some beams. For example, a satellite may avoid having all of its beams active at the same time. A satellite might implement power sharing among satellite beams or implement different satellite beam patterns / size (i.e., wide or narrow) across the satellite footprint. The satellite might periodically activate or deactivate various satellite beams based on one or more constraints, such as the nominal Equivalent Isotropic Radiated Power (EIRP) density per satellite beam, available power, or feeder link bandwidth.

[0045] Discontinuous transmission (DTX) and discontinuous reception (DRX) refer to power saving features in which a device can disable transmission or reception of radio frequency (RF) signals during a configured non-active period (also referred to as an “OFF” period). When a base station implements DTX / DRX for a cell or beam, the DTX / DRX is referred to as cell / beam DTX / DRX to distinguish from implementations of DTX / DRX (such as connected discontinuous reception (c-DRX)) at a user equipment (UE). Cell / beam DTX / DRX is a network energy saving (NES) feature of the base station. A cell / beam DTX / DRX configuration can indicate ON / OFF periods (also referred to as active / non-active periods, respectively) when the base station will operate a cell (or beam) serving a UE. During OFF periods, the base station and the UE can conserve power by limiting radio frequency transmission / reception. Cell DTX / DRX typically applies to an entire cell (including all the beams of that cell). Beam DTX / DRX can apply to one or more beams within a cell. For brevity, this disclosure uses the term cell / beam DTX / DRX configuration to refer to any DTX / DRX configuration by which a UE can determine an OFF period of a cell or beam. In some implementations, a satellite provides a cell / beam DTX / DRX configuration using radio resource control (RRC) messaging for UEs in an RRC connected state. Alternatively, or additionally, the satellite can provide a cell / beam DTX / DRX configuration via downlink control information (DCI), or media access control (MAC) control element (CE) control signaling. In some implementations, a satellite provides a cell / beam DTX / DRX configuration using system information broadcast (SIB) messaging for UEs in the RRC idle / inactive state (e.g., not in RRC connected state).

[0046] According to 3GPP specifications, a UE is required to monitor the downlink radio link quality based on configured resources for a radio link monitoring (RLM) reference signal (RLM- RS) to detect the downlink radio link quality of a serving cell (referred to as a primary cell, orPC ell). The configured RLM-RS can include synchronization signal blocks (SSBs), channel state information reference signals (CSI-RSs), or both. For RLM, a UE might periodically or continuously assess the quality of the radio link by monitoring the reference signal received power (RSRP) and / or reference signal received quality (RSRQ) of the RLM-RS, ensuring the signal remains above a predefined threshold. Beam Failure Detection (BFD) is a similar technique that enables a UE to detect the loss of a beam by monitoring beam-specific reference signals (RSs). If the signal strength drops below the threshold for a certain duration, the UE triggers a radio link failure (RLF) or beam failure event. Based on the RLF or beam failure event, the UE searches for another cell or beam to re-establish a radio connection to the network.

[0047] This disclosure provides systems, methods, and apparatuses for managing RLM / BFD measurements for an NTN that implements cell / beam DTX / DRX. A satellite provides a cell / beam DTX / DRX configuration to inform the UE of configured OFF periods during which the satellite does not transmit downlink reference signals. While being served by a cell or beam that occasionally does not transmit downlink reference signals (e.g., being turned off completely during an OFF period), the UE can suspend (e.g., stop, refrain, pause) the RLM / BFD operations during the OFF period. In some aspects, the UE can skip a serving cell / beam measurement (for mobility purposes) at the time when the serving cell / beam does not transmit downlink reference signals. In some aspects, a satellite can provide a cell / beam DTX / DRX configuration for a neighboring cell. The UE can skip the neighboring cell measurement during times (e.g., OFF periods) when the neighboring cell does not transmit downlink reference signals. Disabling cell / beam measurements during OFF periods can enable the UE to conserve power.

[0048] The concepts of this disclosure might be implemented differently depending on whether the UE has a configured RRC connection or not. Some example implementations of this disclosure describe messaging and operations for a UE in an RRC connected state. Other example implementations apply to a UE in an RRC idle or RRC inactive state. While some examples describe specific message types, the concepts can be adapted to different message types or implementations.

[0049] In the context of UE mobility, a UE might normally perform serving cell measurements and neighboring cell measurements. Using the techniques of this disclosure, a UE can stop / suspend / refrain / pause the serving cell measurements during times when the serving beam is not transmitting downlink reference signals associated with mobility (e.g., SSB, CSI-RS, cellspecific reference signal (CRS), among other examples). If the UE were to perform serving cellmeasurements during OFF periods, the UE could obtain an inaccurate measurement result. For the neighboring cell measurement, the UE can refrain from measuring the beam of a neighboring cell during configured OFF periods of the neighboring cell when the neighboring cell is not transmitting the downlink reference signals associated with mobility. In some aspects, a network can provide a measurement configuration or neighboring cell configuration that includes the cell / beam DTX / DRX configuration of the neighboring cell.

[0050] In some aspects, a network can configure a UE power saving feature called connected discontinuous reception (c-DRX). C-DRX is designed to reduce power consumption in a UE while it is in the RRC connected state. In c-DRX, the UE periodically alternates between active and sleep modes based on a pre-configured DRX cycle. During the active periods, the UE monitors a physical downlink control channel (PDCCH) for potential incoming data or control signals. During the sleep periods, the UE turns off its radio receiver to save battery power. The network provides a c-DRX configuration indicating the DRX cycle, the DRX period, on-duration timer, and / or inactivity timer. The c-DRX configuration is typically based on the UE's service requirements and mobility conditions. In accordance with aspects of this disclosure, a network configures the c-DRX configuration based on the cell / beam DTX / DRX configuration. For example, the c-DRX configuration can define a UE DRX periodicity that is an integer multiple of the cell / beam DTX periodicity. By coordinating the c-DRX configuration with the cell / beam DTX / DRX configuration, the network can ensure that the UE DRX active period aligns with every X instances of the cell / beam DTX ON period. In this way, the c-DRX configuration can implicitly indicate a DTX OFF period for a cell / beam. The c-DRX configuration is another mechanism for the network to inform the UE regarding DTX OFF periods for a cell / beam.

[0051] Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. Absent the techniques of this disclosure, the UE might undesirably declare a radio link failure or beam failure based on inaccurate measurements due to the absence of downlink reference signals during cell / beam DTX OFF periods. The UE might initiate a radio link search, beam failure recovery, or cell reselection procedure even if the serving beam is still the best beam for the UE. The UE might attempt to switch to another suboptimal cell / beam, which may result in poor UE performance and compromise the system throughput as a whole. Additionally, the RLM / BFD measurements (and potentially unnecessary cell / beam search) can unnecessarily consume power. The potential technical advantages include power saving for the NTN node and UE during OFF periods of acell / beam DTX configuration. The techniques of this disclosure improve mobility-related measurements and radio link monitoring by performing beam / cell measurements during ON periods (and not during OFF periods) of serving and / or neighbor cells.

[0052] The examples of this disclosure are based on NTN technology. An NTN node is described as a satellite. In various implementations, the NTN node can be any type of airborne or spaceborne device that operates multiple beams for communicating with another device. As future developments enable other types of devices (such as loT devices, wearables, robots, etc.) to communicate with another device using more than one beam, the concepts of this disclosure can extend to such devices.

[0053] FIG. 1 shows an example wireless communication system 100 including a UE 102 and a non-terrestrial network in which an NTN node 101 provides a beam DTX / DRX configuration to the UE 102. An NTN extends or augments the service capability of a wireless communication system. An NTN refers to a network, or segment of networks, using radio frequency (RF) resources on board an NTN node 101 (such as a spaceborne vehicle or an airborne vehicle). An NTN node 101 can belong to one of several types based on altitude, orbit, and beam footprint size. FIG. 1 shows an NTN node 101 as a satellite 104. A satellite 104 can support a transparent or a regenerative (with on board processing) payload architecture, as further described with reference to FIG. 2A and FIG. 2B. The satellite 104 typically generates several beams for a given service area bounded by the satellite’s field of view. For a transparent payload implementation (as shown in FIG. 2A), a satellite 104 can apply RF filtering and frequency conversion and amplification, and not change the waveform signal. For a regenerative payload implementation (such as shown in FIG. 2B), a satellite 104 can apply RF filtering, frequency conversion and amplification, demodulation and decoding, routing, and coding / modulation.

[0054] An NTN gateway 108 (sometimes also referred to as a “sat-gateway” or “GW”) communicatively couples the satellite 104 to ground components of the example wireless communication system 100 (such as a ground NTN BS 106, a core network (CN) 110, or other data network resources). In some deployments, the NTN node 101 (e.g., satellite 104) can perform some or all functions of a base station (shown as BS 106). The BS 106 can be included on-board the satellite 104 or can be partially or wholly located on the ground (shown as ground NTN BS 106'). In this disclosure, the term BS 106 can refer to either or both of the BS 106' on the ground (when present) or the BS 106 (when onboard the satellite 104). The satellite 104, the NTN gateway 108, and the BS 106 / 106' form part of a RAN (sometimes referred to as an NTNRAN). In some implementations, the radio access technology for the NTN RAN is based on 5G NR. Alternatively, the radio access technology for the NTN RAN can use an Evolved Universal Terrestrial Radio Access (E-UTRA) air interface for 4G LTE, or another radio access technology such as NB-IoT, among other examples. Any number of RANs can be communicatively coupled to the CN 110. The CN 110 can be implemented as an evolved packet core (EPC), a fifth generation (5G) core (5GC), or a sixth generation (6G) core.

[0055] In this disclosure, the NTN node 101 can refer to the satellite 104, the BS 106 / 106', or collectively to the satellite 104 and the BS 106 / 106', such that the phrases or reference numbers can be interchangeable. When the UE 102 is within a coverage area of the satellite 104, the UE 102 can establish a radio connection to the satellite 104 via a first NTN cell 126. The first NTN cell 126 refers to a coverage area in which the satellite 104 operates as part of a radio network. The radio network can be associated with a footprint on the surface of the Earth or could be deployed in air, space, a spaceship, or other planetary objects. The radio connection between the UE 102 and the satellite 104 can also be referred to as service link 103. When the UE 102 and the BS 106 have established the service link 103, the UE 102 is said to be in an RRC connected (RRC CONNECTED) state. After the UE is in the RRC CONNECTED state, the UE 102 might send a network registration request or other uplink non-access stratum (NAS) messages to the CN 110 via the NTN node 101 (e.g., the satellite 104 and the BS 106). The satellite 104 communicates the network registration request or other NAS messages to the CN 110 via a feeder link 107 that communicatively couples the satellite 104 to the NTN gateway 108. The CN 110 determines whether to accept or reject the network registration based on user subscription information. Depending on where the UE 102 is located or what RAN is being accessed, the CN 110 might accept or reject the network registration request. The CN 110 provides the network registration accept / reject or other downlink NAS messages to the satellite 104 via the NTN gateway 108 and feeder link 107. After registering to the CN 110, the UE 102 can release or suspend the radio connection (e.g., service link 103). An RRC idle (RRC IDLE) state refers to a state where the radio connection is released or not yet established. An RRC inactive (RRC INACTIVE) state refers to a state where the radio connection is suspended. For simplicity, the term “idle state” is used below to refer to the RRC IDLE state and / or RRC INACTIVE state. The term “connected state” refers to the RRC CONNECTED state.

[0056] In terms of the satellite moving pattern, there are three types of service links that are supported in NTN:• Earth-fixed: provisioned by beam(s) continuously covering the same geographical areas all the time (e.g., the case of Geostationary Earth Orbit or Geosynchronous Orbit (GEO / GSO) satellites)• Quasi-Earth-fixed: provisioned by beam(s) covering one geographic area for a limited period and a different geographic area during another period (e.g., the case of Low Earth Orbit or Medium Earth Orbit (LEO / MEO) satellites capable of using steerable beams), or• Earth-moving: provisioned by beam(s) whose coverage area slides over the Earth surface (e.g., the case of LEO / MEO satellites using fixed or non-steerable beams).

[0057] With LEO / MEO satellites, the satellite 104 can provide either quasi -Earth -fixed cell coverage or Earth-moving cell coverage. With GEO satellites, the satellite 104 can provide Earth fixed cell coverage.

[0058] The NTN node 101 (sometimes also referred to as a network entity) typically transmits downlink reference signals, e.g., synchronization signal blocks (SSBs) or channel state information reference signals (CSI-RSs), for the UE 102 to utilize to maintain downlink and uplink communication with the NTN node 101. To reduce power consumption, the NTN node 101 may not transmit some of the SSBs and / or CSI-RSs in the active bandwidth part (BWP) of a serving cell. For example, the NTN node 101 might implement network energy saving (NES) techniques in which the NTN node 101 eliminates or reduces some uplink and downlink transmissions. Cell DTX / DRX is an NES feature for a network entity to inform UEs of the active / non-active pattern of signals for a cell. The legacy cell DTX / DRX configuration is a cellwide configuration. In some implementations, the NTN node 101 can transmit beam-specific information to indicate active / non-active patterns on a per-beam basis. For example, the NTN node 101 can operate multiple NTN cells 126, 127, where each cell includes a set of beams. Although shown as non-overlapping coverage areas, the cells 126, 127 can be partially or fully overlapping.

[0059] In FIG. 1, the NTN node 101 operates multiple beams (shown as a first beam 124 and a second beam 125). The first beam 124 and the second beam 125 can be in the same cell 126 (as shown in FIG. 1) or can be in different cells. To manage power output and / or conserve energy, the NTN node 101 can operate the beams using discontinuous transmi ssion / recepti on (referred to as beam DTX / DRX operation). As further described with reference to FIG. 3B, each beam can have a different pattern for active / non-active periods. The NTN node 101 can provide one or more cell or beam DTX / DRX configuration(s) 140 to the UE 102. For example, a first beamDTX / DRX configuration can indicate the active / non-active periods for a beam 124. A second beam DTX / DRX configuration can indicate the active / non-active periods for a second beam 125. The UE 102 can use the beam DTX / DRX configurations to determine when to monitor a particular beam for downlink signals or when to communicate uplink transmissions to the NTN node 101. For example, the UE 102 can monitor the physical downlink control channel (PDCCH) of the beam 124 during an active period of beam 124.

[0060] Aspects of this disclosure refer to active and non-active periods of a beam. An active period can also be referred to as an ON period. A non-active period can refer to a period when the satellite completely or partially disables beam communication. In some implementations, a non-active period refers to an OFF period in which the satellite does not communicate (e.g., transmit or receive according to configured beam DTX or beam DRX). In some implementations, during a non-active period, the satellite may transmit some common downlink signals (such as system information, synchronization signals, and / or reference signals). Such non-active period can be referred to as a COMMON period (or other term) to distinguish from an OFF period. In some aspects, a cell / beam DTX / DRX configuration can indicate ON / OFF / COMMON periods. Alternatively, or additionally, the cell / beam DTX / DRX configuration can indicate whether the satellite 104 will continue to transmit common downlink signals during a configured OFF period. For brevity in this disclosure, unless otherwise indicated, the satellite 104 does not transmit common control signaling or reference signals during the OFF period of a particular cell / beam.

[0061] In accordance with aspects of this disclosure, the UE refrains 170 from performing cell / beam measurements of various cells / beams during the respective OFF periods of the cells / beams. The UE 102 determines the OFF periods based on the cell / beam DTX / DRX configuration. In some aspects, the UE 102 suspends a RLF and BFD procedure during the OFF periods to prevent unnecessary radio link or beam failure recovery processes that would normally otherwise be triggered after a period of time without cell / beam measurements. Furthermore, the UE 102 can suspend cell / beam measurements of neighboring cells / beams (such as the second beam 125 or any of the beams in the second NTN cell 127) during configured OFF periods of those cells / beams.

[0062] FIG. 2A is a block diagram of an example wireless communication system 200A implementing a BS 106 (on the ground) connecting to a satellite 104 via an NTN gateway 108 using a transparent payload implementation. The satellite 104, the NTN gateway 108, and the BS 106 collectively form a RAN 205 similar to a RAN that would typically be created by aterrestrial BS. The example wireless communication system 200A uses one type of NTN deployment referred to as transparent payload architecture, which involves an NTN gateway 108 and a “transparent” satellite 104 for extending the range of a Uu interface. The Uu interface refers to the link between the UE 102 and a base station. In some implementations, the satellite 104 implements a frequency conversion and an RF amplifier in both the uplink and downlink directions. With that being said, the satellite 104 function is similar to that of an analogue RF repeater. As a result, the satellite 104 repeats the Uu radio interface from a feeder link 107 (between the NTN gateway 108 and the satellite 104) to the service link 103 (between the satellite 104 and the UE 102) in the downlink direction and vice versa in the uplink direction. The Satellite Radio Interface (SRI) on the feeder link is the Uu interface, and the NTN gateway 108 supports functions to forward the signal of the Uu interface. The NTN gateway 108 can be placed at the same site as the BS 106 location, or can be connected to the BS 106 at a distance via a wired link. It is also possible to connect more than one NTN gateway 108 to a BS 106. Different transparent satellites may be connected to the same base station on the ground, via the same NTN gateway, or via different NTN gateways. FIG. 2A also shows a data network 210 that is accessible via the CN 1 10.

[0063] FIG. 2B shows a block diagram of an example wireless communication system 200B implementing an NTN BS 106 onboard a satellite 104 using a regenerative payload implementation. The BS 106 can perform some or all of the functions of a base station including operating the RAN 205. The service link (labeled Uu interface) is shown between the UE 102 and the BS 106. In the example of FIG. 2B, the feeder link 107 from the BS 106 to the NTN gateway 108 can be referred to as the SRI. In this example, the SRI is a transport link between the NTN gateway 108 and the satellite 104 that carries traffic for the Ng (or SI) interface. The NTN gateway 108 at one end of the SRI serves as an intermediate node forwarding the Sl / Ng traffic to and from the CN 110. The Ng interface from the BS 106 includes a portion over the SRI (shown as Ng over SRI) and a portion on the ground. Different regenerative satellites can connect to the same CN 110 on the ground, via the same NTN gateway 108, or via different NTN gateways.

[0064] In some implementations, a first portion of the base station functionality (shown as BS 106) can be implemented on the satellite 104 while a second portion of the base station functionality (shown as BS 106') can be implemented at a ground entity. For example, in a disaggregated network, a base station can be divided into two components: the Distributed Unit(DU) and Centralized Unit (CU). In an example, the BS 106 can operate as a DU that handles baseband processing, including RF signal processing and modulation / demodulation. The BS 106' can be an example CU that manages higher-layer tasks like resource management, scheduling, and network optimization.

[0065] FIG. 3A shows an example cell / beam DTX / DRX operation for a satellite 104 operating multiple beams. In FIG. 3A, the satellite 104 operates four beams to increase the coverage of the first NTN cell 126. The beams are labeled “beam 1,” “beam 2,” “beam 3,” and “beam 4” for reference purposes. Beam 1 can be an example of the first beam 124 described with reference to FIG. 1. Beam 2 can be an example of the second beam 125 described with reference to FIG. 1.

[0066] In an example scenario (as a premise for FIG. 3 A), the satellite 104 has limited power or limited feeder link bandwidth. Based on such limitations, the satellite 104 activates at most two downlink beams at the same time. During the first time period Ti shown at example 300, the satellite 104 activates beam 1 and beam 4. For example, the first time period Ti can be a time that includes subframel (sfl) through subframe5 (sf5) shown with reference to FIG. 3B. During a second time period T2 shown at example 301, the satellite 104 activates a beam 2 and beam 3. For example, the second time period T2 can be a time that includes sf6 through sflO shown with reference to FIG. 3B. Although these time periods are shown as mutually-exclusive, in various implementations they can overlap. For example Ti can include sf6 and / or T2 can include sf5.

[0067] The example beam DTX / DRX operation in FIG. 3A can explain a potential technical advantage of managing beam measurement based on the cell / beam DTX / DRX configuration. UEs (not shown) located at the coverage areas of beam 2 and beam 3 may not be able to operate normally (e g., receive downlink reference signals, monitor the PDCCH, etc.) during the first time period Ti, since those are non-active (or active below the nominal EIRP) during that time period. Those UEs will resume their normal operations (such as the operations in RRC connected state or monitoring for paging messages) during the second time period T2 where beam 2 and beam 3 once again become active. To make UEs aware of when to pause / resume the communication or monitoring, the NTN node 101 can inform the UEs of the active / non-active pattern of each beam. A beam DTX / DRX configuration can inform the UEs of the active / non- active patterns on a per-beam (or per-beam-group) basis. For example, beam 1 and beam 4 can form a first beam-group, and beam 2 and beam 3 can form a second beam-group. (See also FIG. 3C.) The beam DTX / DRX configurations enable UEs to act accordingly based on which beam a UE is monitoring or connected to. The beam DTX / DRX configurations can provide potentialtechnical advantages such as enabling efficient communication during active periods and preventing UEs from wasting their power during the beam non-active periods.

[0068] In FIG. 3A, the various beams are shown as covering different footprints. In some deployments, the various beams can cover adjacent footprints. In some deployments, the footprint of the various beams can be partially or fully overlapping. Thus, it is possible for a UE to be within the coverage area of more than one beam. Since each beam can have a different active / non-active pattern, in some implementations, the satellite 104 provides beam DTX / DRX configurations to the UE to inform the UE about the active / non-active patterns on a per-beam basis. In some implementations, the satellite 104 provides cell DTX / DRX configurations to the UE to inform the UE about the active / non-active patterns on a per-cell basis, where each cell may consist of a subset of the total beams offered by the satellite 104.

[0069] FIG. 3B shows a diagram 302 of example patterns for cell / beam DTX / DRX operation. The patterns in FIG. 3B are provided as an example, and other deployments can have different patterns. In the example of FIG. 3B, during a first period Ti, a first beam (such as the first beam 124 in FIG. 1 or FIG. 3A) is in the active state (such as an “ON” state). Thus, with respect to the first beam, the first period Ti can be referred to as an ON period. Meanwhile, a second beam (such as second beam 125 in FIG. 1 or FIG. 3 A) can be in a non-active state (such as an “OFF” state). Thus, with respect to the second beam, the first period Ti can be referred to as an OFF period. FIG. 3B shows example patterns of a first beam with subframes 1-5 in an ON period and a second beam with subframes 1-5 in an OFF period during the first period Ti. During the second period T2, subframes 6-10 are in the OFF period for the first beam and are in the ON period for the second beam. Although the example of FIG. 3B shows the first beam and the second beam having opposite states, other beam DTX / DRX configurations are possible. Each beam can have a different beam DTX / DRX operation based on power limitations, traffic requirements, feeder link capacity, etc. Referring again briefly to FIG. 1, the cell / beam DTX / DRX configuration 140 can indicate the ON periods and OFF periods of the beam 124 and the second beam 125.

[0070] The example in FIG. 3B shows the beams having alternating ON periods and OFF periods. An OFF period is an example of a non-active state. As further described with reference to FIG. 4A, another example of a non-active state can include a COMMON period. During the COMMON period, an NTN node can transmit some common downlink signals (such as system information, synchronization signals, and / or reference signals). In some aspects, a beam DTX / DRX configuration can indicate 0N / 0FF / C0MM0N periods. Alternatively, oradditionally, the beam DTX / DRX configuration can indicate whether the satellite will continue to transmit downlink reference signals during a configured OFF period.

[0071] Using FIG. 3B, a potential technical problem with legacy operation is described. If the satellite 104 does not transmit the common control signals (e.g., downlink reference signals) in the first beam 124 during OFF periods (shown at subframes 6-10) and if the UE were to continue attempting RLM / BFD measurements during the OFF period, the UE would obtain no or low signal strength of the downlink reference signals. In other words, the UE could detect out of sync conditions. A physical layer of the UE could provide out-of-sync indications to a higher layer of the UE. Based on a quantity (n310) of out-of-sync indications and expiry of a timer t310, the UE may declare an RLF. The UE may attempt to switch to another cell / beam, which may result in poor UE performance or selection of a sub-optimal cell / beam. Thus, in accordance with aspects of this disclosure, the UE may suspend RLM operations (such as measurements, n310 counter or t310 timer) during the configured OFF period of a particular beam. Although shown in relation to RLM, similar concepts apply to BFD which is also based on beam measurements, counter, and timer, to detect a beam failure and initiate a beam failure recovery.

[0072] FIG. 3C shows a UE potentially in coverage of multiple beams at various times based on overlapping beams. In the first example 303, coverage of the first beam 124 and the second beam 125 partially overlap. For example, the beam 124 can have a first orientation and the second beam 125 can have a second orientation. In some implementations, a satellite can operate multiple beams in the first orientation (such as rows) and multiple beams in the second orientation (such as columns). The designation of rows / columns are for ease of reference and could describe beams having elliptical footprints with a major axis in various orientations based on elevation angle, altitude, azimuth, etc. The UE 102 can be located in the coverage area of the first beam 124 and the second beam 125. Depending on direction of travel (for the NTN node or the UE), one beam may be better suited for serving the UE 102 compared to the other beams. A satellite may decide to move the UE 102 from one beam to the other based on channel state information, predicted beam failure, the satellite moving trajectory, the UE position, or service requirements, among other example criteria. The satellite can inform the UE 102 regarding the beam DTX / DRX configurations of the various beams (such as the first beam 124 and the second beam 125) that might serve the UE 102 at various active periods. The UE 102 can refrain from cell / beam measurements of particular beams in the OFF periods (on a per-cell basis or per-beam basis) during which the satellite does not transmit downlink reference signals.

[0073] In a second example 304, FIG. 3C shows a scenario where coverage areas of various beams are different sizes and may have partially or completely overlapping footprints. For example, a first beam 124 may completely overlap the coverage from a second beam 125. The active / non-active periods of the beam 124 and the various other beams (including the second beam 125) can vary. For example, the satellite may configure periodic active periods for the first beam 124 to enable synchronization and paging for idle / inactive UEs. The satellite may configure longer or shorter active periods for the other beams based on the quantity of UEs and / or traffic flows in other beams where longer active periods are configured for beams having more UEs or higher traffic and shorter active periods are configured for beams having fewer UEs or less traffic.

[0074] FIG. 4A shows example states for cell / beam DTX / DRX operation. The diagram 400 shows three example cell / beam states: an ON state 492, a COMMON state 493, and an OFF state 494. The ON state 492 is an example active state. The COMMON state 493 and the OFF state 494 can be referred to as non-active states (sometimes also referred to as “inactive” states).

[0075] When the satellite has a particular cell or beam in the ON state 492, the satellite can transmit control signaling and data to a UE via that cell / beam. For a cell / beam in the OFF state 494, the satellite refrains from transmitting or receiving signals via that cell / beam, such that there is no beam transmission during the non-active period of an OFF state. In some implementations, a cell / beam DTX / DRX configuration can indicate active / non-active periods to refer to the ON / OFF states, respectively.

[0076] In some aspects, the satellite might continue to transmit limited signaling, such as common signaling for paging and / or system information without user data. Common downlink signals consume less power. Thus, it is possible for an NTN node to satisfy power budget constraints or energy savings while still transmitting the common signaling. Thus, this disclosure contemplates a non-active state, referred to as COMMON state 493, that achieves advantages of a non-active period for beam DTX / DRX operation while still providing limited signaling. The COMMON state 493 is referred to as “COMMON” to reflect that the limited downlink signals are broadcast or group-common signals. The COMMON state 493 can be referred to by other terms, such as limited state, power saving (PS) state, partial-active state, or other terms. In some implementations, the COMMON state 493 is a variant of the OFF state 494 where the satellite continues to transmit limited signaling during the OFF state 494.

[0077] In some implementations, a cell / beam DTX / DRX configuration can indicate a pattern for the ON / OFF / COMMON states, where the periods for the OFF state and the COMMON state are distinctly configured in the cell / beam DTX / DRX configuration. Alternatively, or additionally, the cell / beam DTX / DRX configuration can indicate whether the OFF state includes transmission of limited signaling, such that part or all of the non-active periods of the OFF state operate similar to the described COMMON state 493.

[0078] FIG. 4B shows example parameters for a cell / beam DTX / DRX configuration 440. The cell / beam DTX / DRX configuration 440 can include a configuration index value 449. In some implementations, the configuration index value 449 corresponds to an index from a set of preconfigured beam DTX / DRX configurations (such as specified in system information or in a technical specification). Alternatively, the configuration index value 449 can be any value that refers to a first unique instance of a cell / beam DTX / DRX configuration 440 to distinguish it from a second unique instance of the cell / beam DTX / DRX configuration 440. An NTN node can indicate the configuration index value 449 in a control signaling message (such as an RRC message) to indicate the unique instance of the cell / beam DTX / DRX configuration 440 that applies to a particular beam.

[0079] In some implementations, the cell / beam DTX / DRX configuration 440 is for DTX only, DRX only, or both DTX and DRX. The cell / beam DTX / DRX configuration 440 can include a configuration type 441A to indicate whether the cell / beam DTX / DRX configuration 440 applies to cell DTX, cell DRX, cell DTX / DRX, beam DTX, beam DRX, or beam DTX / DRX. Additional example parameters include indications of a periodicity for the active period, such as on duration 44 IB, a start offset 441C, a slot offset 44 ID, a cycle 44 IE, and an initial activation status 44 IF, among other examples. The on duration 44 IB can indicate the active duration at the beginning of a beam DTX / DRX cycle. The start offset 441C can indicate the subframe where the cell / beam DTX / DRX cycle starts. The slot offset 44 ID can indicate the delay before starting the on duration timer. The cycle 44 IE can indicate the cell / beam DTX / DRX cycle period. The initial activation status 44 IF can indicate the initial activation status of cell / beam DTX / DRX operation.

[0080] In some implementations, the cell / beam DTX / DRX configuration 440 indicates a pattern reflecting the time-varying beam status in one of the three states (e.g., {ON, COMMON, OFF} as described with reference to FIG. 4A), where the ‘ON’ state means the beam is operating normally and can be accessed by any legacy UE, the ‘OFF’ state means the beam is completely turned off and hence is not visible to any UE, and the ‘COMMON’ state means the beam transmitsonly the common signal(s) used for initial access, cell search, paging, and / or random access purposes. A beam transmitting only the common signals is visible to the legacy UE and can be used to transmit the paging message as well as the system information but cannot be used to transmit other dedicated control messages and user data. In some implementations, the on duration 44 IB timer field and / or a COMMON duration timer field indicate one of the following ON / COMMON duration values in milliseconds { 1, 2, 3, 4, 5, 6, 8, 10, 20, 30, 40, 50, 60, 80, 100, 200, 300, 400, 500, 600, 800, 1000, 1200, 1600}. The cell / beam DTX / DRX configuration 440 can include a CycleStartOffset field (e.g., start offset 441C) indicating one of the following DTX / DRX cycle values in milliseconds { 10, 20, 32, 40, 60, 64, 70, 80, 128, 160, 256, 320, 512, 640, 1024, 1280, 2048, 2560, 5120, 10240}, an offset value (e.g., start offset 441 C) smaller than the DTX / DRX cycle value (e.g., cycle 441E), and a slot offset field (e.g., slot offset 441D) indicating a slot offset value ranging from 0 to 31.

[0081] In some implementations, the cell / beam DTX / DRX configuration 440 includes a field 441G indicating a time for next ON cycle. For example, the cell / beam DTX / DRX configuration 440 can be a rough cell / beam DTX / DRX configuration that provides minimal information to inform the UE of the next ON duration for a cell / beam where the UE can obtain a full cell / beam DTX / DRX configuration. In some implementations, the field 441G can include an action delay value indicating time or time period (such as a quantity of symbols, milliseconds, seconds, etc.) when the cell / beam DTX / DRX configuration becomes active or when the next ON period starts. In some implementations, the cell / beam DTX / DRX configuration 440 includes an indication 441H to enable a UE to shift a paging occasion when the paging occasion occurs during an OFF period. If enabled, the UE can shift a start time for the paging occasion to a next ON period (or next COMMON period). In some implementations, the cell / beam DTX / DRX configuration 440 includes an indication 441J indicating that the NTN node will transmit common signaling during a configured OFF period (such that the OFF period is similar to the COMMON state 493 described with reference to FIG. 4A). In some implementations, the indication 441J has a value indicating that the NTN node will NOT transmit common signaling during a configured OFF period.

[0082] In some implementations, the cell / beam DTX / DRX configuration 440 can be beamspecific. To enable identification of which beam is associated with the cell / beam DTX / DRX configuration 440, the cell / beam DTX / DRX configuration 440 can include beam matching information 442. The beam matching information 442 can refer to any information that matchessystem information 422 or an RRC message and that can identify to which beam (or beam group) the cell / beam DTX / DRX configuration 440 applies. Examples of beam matching information 442 include a transmission configuration indicator (TCI) state 442A, a beam ID or index 442B, or an ID or index of related SSB or CSI-RS 442C, among other examples.

[0083] FIG. 4C shows an example technique for configuring and activating cell / beam DTX / DRX configurations. In some implementations, a network can pre-configure a list of candidate cell / beam DTX / DRX configurations (444A, ..., 444D). For example, the NTN node can configure the candidate cell / beam DTX / DRX configurations using RRC signaling (e.g., RRCReconfiguration)' or system information. Alternatively, the pre-configured candidate cell / beam DTX / DRX configurations can be specified in a technical specification. Each configuration may include a subset or all of the parameters described with reference to FIG. 4B. In some implementations, a configuration message can include first portion that includes common parameters that apply to multiple cell / beam DTX / DRX configurations and one or more second portions that include beam-specific parameters for one or more candidate cell / beam DTX / DRX configurations.

[0084] The NTN node can activate a particular one of the candidate cell / beam DTX / DRX configurations (444A, ..., 444D) using control signaling 445. In some implementations, the control signaling 445 can be referred to as a cell / beam DTX / DRX activation indication (or DCI for activating a DTX / DRX configuration). For example, the cell / beam DTX / DRX activation indication can refer to one of the candidate cell / beam DTX / DRX configurations (444A, ..., 444D) using a configuration index value 449. In some implementations, the control signaling 445 (e.g., cell / beam DTX / DRX activation indication) can also include beam matching information 442. Thus, the control signaling 445 can reduce signaling overhead by linking a reusable cell / beam DTX / DRX configuration to a particular cell or beam and can dynamically enable or disable cell / beam DTX / DRX operation on a per-cell, per-beam-group, or per-beam basis. In some implementations, the control signaling 445 is a DCI field on a PDCCH. Alternatively, or additionally, the NTN node can transmit the control signaling 445 in a MAC CE message or a system information block (SIB) broadcast message. In other implementations, the control signaling 445 is a dedicated RRC message such as the RRC message providing the TCI state configuration or providing the CSI-RS configuration.

[0085] Next, several example scenarios in which a UE and / or a RAN perform the techniques of this disclosure for configuring a UE with the beam-specific active / non-active patterns (e.g., thebeam DTX / DRX configurations) of the serving and neighboring beams are discussed with reference to FIGS. 5-11. Generally speaking, similar events in Figs. 5-11 are labeled with reference numbers that have the same lower-order digits. For brevity, similar messages or events are not discussed in detail in each instance, but the discussion of a certain event with reference to one of the figures also applies to similar messages or events in other figures. For example, operations / messages 572, 672, 872, 1072, 1172, 1272, 1572, 1772, etc., refer to similar concepts such as the UE stopping or suspending cell / beam measurements during a configured OFF period. For simplicity, the term “idle state” is used below to refer to the RRC IDLE state and / or RRC INACTIVE state. The term “connected state” refers to the RRC CONNECTED state. FIG. 5 includes concepts applicable to any RRC state. FIG. 6 through FIG. 10B show operations of the UE 102 in a connected state. FIG. 11 shows how the UE 102 can use the disclosed techniques during idle state.

[0086] FIG. 5 shows a messaging diagram 500 and operations of a UE 102 coordinating cell / beam measurements based on a cell / beam DTX / DRX configuration. The UE 102 determines when to suspend and when to resume the cell / beam measurements based on OFF periods configured in the cell / beam DTX / DRX configuration(s). In FIG. 5, the UE 102 obtains a DTX / DRX configuration 540 for beam 124. Beam 124 can be either a Synchronization Signal and Physical Broadcast Channel Block (SSB) beam or a Channel Status Information Reference Signal (CSI-RS) beam. In some implementations, the DTX / DRX configuration 540 can be applicable to only the beam serving the UE 102 (i.e., the Beam 124), or can be applicable to every beam in the same cell including the beam 124. When the DTX / DRX configuration provided in step 540 is a beam-specific configuration, the BS 106 may also provide the DTX / DRX configurations for other beams (other than Beam 124) of the same cell to the UE 102 in step 540, where each DTX / DRX configuration is associated with either an SSB index or a CSI-RS resource identity. In some implementations, the cell / beam DTX / DRX configuration contains only the DTX configuration without having the DRX configuration. In some implementations, the cell / beam DTX / DRX configuration can include a pattern indicating ON / OFF periods (or ON / COMMON / OFF periods) as described with reference to FIG. 4A and FIG. 4B. In some implementations, the UE 102 receives an indication 541 (either with the cell / beam DTX / DRX configuration or via a separate message) that indicates whether there will be common control signals (including but not limited to the reference signals used for the measurement, for the radio link monitoring, and for the beam failure detection purposes) being transmitted in the ‘OFF’state. In this example, there will be no common control signal being transmitted in the ‘OFF’ state (i.e., beam 124 can be considered as being completely turned off in the OFF period 594). FIG. 5 shows the ON period 592 and the ON period 595 that precede and follow the OFF period 594, respectively.

[0087] In some implementations, the network sends a cell / beam DTX / DRX activation indication, such as a DCI 545 for activating all or a specific cell / beam DTX / DRX configuration(s). The DCI can be a dedicated DCI (dedicated to the UE 102) or a group-based DCI (common to a group of UEs). In another implementation, the UE 102 activates / applies the cell / beam DTX / DRX configurations directly upon receiving the cell / beam DTX / DRX configuration 540 for the beam 124, without waiting for the DCI or any other additional control signal.

[0088] Shown at block 570, the UE refrains from performing cell / beam measurements of the beam 124 based on the cell / beam DTX / DRX configuration for the beam 124 (or the cell including the 124). For example, at block 572, the UE 102 stops or suspends the cell / beam measurements at the beginning of the OFF period 594. Performing cell / beam measurements during the OFF period 594 is not useful since the satellite 104 does not transmit downlink reference signals (shown as non-transmitted RSs 555) during the OFF period. Later, at the beginning of the next ON period 595, at block 574, the UE 102 starts or resumes the cell / beam measurements for the beam 124, since the satellite 104 also starts to transmit the RS(s) 585 from the beginning of the ON period 595.

[0089] FIG. 6 shows a messaging diagram 600 of an example scenario in which a UE in the connected state determines when to suspend and when to resume RLM and / or the BFD operations based on the cell / beam DTX / DRX configuration(s). The diagram 600 is generally similar to the diagram 500, with the differences discussed below. Events 540, 541 and 545 have the same meaning as described with reference to FIG. 5. In FIG. 6, the UE 102 initially connects to the BS 106 through the satellite 104, in an NTN cell offered by the beam 124. FIG. 6 shows the UE 102 remaining in the RRC connected state 602. Thus, in some implementations, the messages / indications in 540, 541, 650 can be implemented using RRC signaling. Alternatively, or additionally, all or part of the messages 540, 541 can be implemented using broadcast signaling (such as via a SIB message).

[0090] In the connected state 602, during the ON period 592, the satellite 104 provides a RLM / BFD RS resource configuration 650. The RLM / BFD RS resource configuration 650configures reference signal resources that the UE 102 would normally monitor for RLM and / or BFD purposes. The RLM / BFD RS resource configuration indicates the RS resource(s) that the UE 102 can measure to determine whether there is a RLF or a beam failure event occurring. For example, the RLM / BFD RS can include SSB(s), CSI-RS(s), or both. However, in the example of FIG. 6, the satellite 104 does not transmit the RLM / BFD RSs during the OFF period 594.

[0091] At block 672, the UE 102 stops or suspends the RLM and / or BFD operations (e.g., measurements, counting out-of-sync indications, or running of a timer) for the beam 124 at the beginning of the OFF period 594. At block 674, the UE 102 starts or resumes the RLM and / or the BFD for the beam 124 at the beginning of the next ON period 595 since the beam 124 also starts to transmit the RS(s) 685 for the RLM and / or the BFD from the beginning of the ON period 595.

[0092] In some implementations, the UE detects several missing or unqualified RS(s) for the RLM and / or the BFD purposes. Shown at block 686, the UE may trigger a RLF or a BFR procedure. The RLF or BFR procedure attempts to recover from the RLF or the beam failure situation by transmitting a Physical Random Access Channel (PRACH) preamble 687 to the BS 106.

[0093] FIG. 7 shows a messaging diagram 700 of an example scenario in which a UE in the connected state determines when to measure or monitor the reference signal (RS) resources configured for RLM / BFD based on the c-DRX configuration aligning with the cell / beam DTX / DRX configuration. The diagram 700 is generally similar to the diagram 600, with the differences discussed below. In FIG. 7, in addition to the cell or beam DTX / DRX configuration, the UE 102 further receives a UE DRX configuration for connected state 602 (i.e., UE c-DRX configuration 760) from the BS 106. The c-DRX configuration 760 indicates a UE c-DRX periodicity (i.e., UE c-DRX cycle length) equal to one or multiple times of the cell / beam DTX / DRX periodicity for the beam 124. In other words, the UE 102 c-DRX active period will align with every A ON periods of the cell / beam DTX active period, where Ais an integer greater than 0.

[0094] The UE 102 then performs the RLM based on configured RSs for the RLM purpose, and complies with the minimum timing requirement defined in 3GPP technical specification (TS) 38.133, section 8.1C.2.2 (for SSB based RLM) or 8.1C.3.2 (for CSI-RS based RLM) while performing the RLM. UE 102 also performs the BFD based on the configured RSs for the BFD purpose, and complies with the minimum timing requirement defined in 3 GPP TS 38.133, section8.5C.2.2 (for SSB based BFD) or 8.5C.3.2 (for CSI-RS based BFD) while performing the BFD. As the minimum timing requirements defined for RLM and BFD in TS 38.133 are based (i.e., proportional to) on the c-DRX cycle length of the UE, it implies that the UE 102 is able to refrain (block 770) from monitoring the RLM / BFD RSs during the UE c-DRX inactive period.

[0095] FIG. 8 shows a messaging diagram 800 of an example scenario in which a UE in the connected state determines when to suspend and when to resume the serving cell measurement based on the cell or the beam DTX / DRX configuration(s). The diagram 800 is generally similar to the diagram 600, with the differences discussed below. In FIG. 8, in addition to providing the cell or beam DTX / DRX configuration 540 of the beam 124 to the UE 102, the BS 106 transmits a serving cell configuration (i.e., the ServingCellConfig IE) 850 including a serving cell measurement object (i.e., the servingCellMO IE) containing the configurations for measuring the serving cell. Based on the cell / beam DTX / DRX configurations for the beam 124, the UE 102 at block 872 stops or suspends the measurement on the serving cell at the beginning of the OFF period 594 and start s / re sum es (block 874) the measurement on the serving cell at the beginning of the next ON period 595.

[0096] The serving cell configuration is typically common to all beams of the cell. In some implementations, the UE 102 determines to stop measurement of the serving cell based on either the fact that the OFF period 594 is common to all the beams of the serving cell, or the fact that the beam 124 is the only beam configured to the UE 102 for the serving cell measurement.

[0097] The serving cell measurement object is often associated with layer 3 (L3) mobility. The satellite 104 transmits the reference signal 885 (e.g., SSB or CSI-RS) for L3 mobility. In the example of FIG. 8, the UE 102 might obtain a poor RSRP, RSRQ, or SINR result from the measurement of the serving cell. Depending on the RSRP / RSRQ / SINR (of the serving cell), shown at block 886, the UE 102 may trigger the intra-frequency or inter-frequency measurement on the neighboring cells.

[0098] FIG. 9 shows a messaging diagram 900 of an example scenario in which a UE in the connected state determines when to perform the serving cell measurement based on the UE c- DRX configuration aligning with the cell or beam DTX / DRX configuration. Events in FIG. 9 are similar to the like-numbered events 540, 541, 850, 545, 760, 885, 886 described with reference to FIG. 7 and FIG. 8. In FIG. 9, in addition to receiving the cell or beam DTX / DRX configurations 540 (with optional DCI 545 activation) and a serving cell configuration 850 including a serving cell measurement object configuration, the UE 102 also receives a c-DRXconfiguration 760. As described with reference to FIG. 7, the UE c-DRX periodicity (i.e., UE c- DRX cycle length) equals to one or multiple times of the DTX / DRX periodicity for beam 124. The UE 102 performs the serving cell measurement based on configurations provided in the serving cell measurement object, and complies with the measurement period requirement defined in 3GPP TS 38. 133, section 9.2C.5.2 (without measurement gap) or 9.2C.6.3 (with measurement gaps) while performing the serving cell measurement. As the measurement period requirements defined for the intra-frequency measurement in TS 38.133 are based on (i.e., proportional to) the c-DRX cycle length of the UE, the UE 102 can refrain (block 970) from performing the serving cell measurement during the UE c-DRX inactive period.

[0099] FIG. 10A shows a messaging diagram 1000A of an example scenario in which a UE in the connected state determines when to measure a neighboring cell based on the cell / beam DTX / DRX configuration(s) included in the measurement object configuration for the neighboring cell. In FIG. 10A, the UE 102 initially connects to the BS 106 through the satellite 104, via a satellite beam in the first NTN cell 126. While remaining in the connected state 602, the UE 102 receives, from the BS 106, a serving cell configuration 850 (i.e., the ServingCellConfig IE) including a serving cell measurement object (i.e., the servingCellMO IE) containing the configurations for measuring the serving cell (i.e., first NTN cell 126). In this scenario, the first NTN cell 126 is closed / adjacent to another cell (i.e., second NTN cell 127). In some implementations, the second NTN cell 127 is provided by another base station (i.e., second BS 106-2) via another satellite (i.e., second satellite 104-2). In some implementations, the second NTN cell 127 can be another cell operated by the BS 106.

[0100] The satellite 104 transmits, and the UE 102 receives, a measurement configuration 1050A (i.e., MeasConfig IE) including a measurement object configuration (measObject IE) for the second NTN cell 127. The measurement object configuration 1050A includes a DTX / DRX configuration for the second NTN cell 127. In some implementations, the measurement object configuration for second NTN cell 127 includes more than one DTX / DRX configuration, and each DTX / DRX configuration is associated with a specific beam (i.e., an SSB index or a CSI-RS identity) in second NTN cell 127. The UE 102 monitors signal quality (e.g., RSRP, RSRQ, or SINR) of the serving cell (i.e., the first NTN cell 126).

[0101] When the signal quality falls below a threshold (i.e., poor RSRP, RSRQ, or SINR in the current serving cell), the UE 102 may trigger (block 886) an intra-frequency and / or interfrequency measurement on the neighboring cells. Normally, the intra-frequency and / or inter-frequency measurement would include all neighboring cells, including the measurement on the second NTN cell 127. However, in the example of FIG. 10 A, the cell / beam DTX / DRX configuration(s) for the second NTN cell 127 indicates that the second NTN cell 127 is currently under an OFF period 1097 and is not transmitting any signals including the RSs for the mobility purpose. At block 1072, the UE 102 refrains from measuring the second NTN cell 127 while the second NTN cell 127 is in the OFF period 1097. Later, at the beginning of the next ON period 1098 of the second NTN cell 127, the UE 102 starts or resumes (block 1074) the measurement on the second NTN cell 127. For example, the UE 102 can measure the SSB or CSI-RS for L3 mobility that are configured in the measurement configuration 1050A for the second NTN cell 127. The UE 102 can determine the timing of the OFF period 1097 and ON period 1098 of the second NTN cell 127 based on the cell / beam DTX / DRX configuration(s) for that cell. In some implementations, if the DTX / DRX configuration for the second NTN cell 127 is provided on a per-beam basis, the UE 102 determines the timing of the OFF period 1097 and ON period 1098 of the second NTN cell 127 based on the common (i.e., overlapped) OFF period of the beams that the UE 102 is configured to measure.

[0102] In the example of FIG. 10A, the results of the neighbor cell measurement and / or the serving cell measurement may trigger the UE 102 to transmit a measurement report 1088 to the BS 106, as long as a criterion for reporting the measurement (e.g., eventA3, eventA4, or eventA5 specified in 3GPP TS 38.331) is fulfilled.

[0103] FIG. 10B shows a messaging diagram 1000B of an example scenario in which a UE in the connected state determines when to measure a neighboring cell based on the cell / beam DTX / DRX configuration(s) of the neighboring cell included in the system information. The diagram 1000B is generally similar to the diagram 1000A. In FIG. 10B, the measurement object configuration 1050B does not include the cell / beam DTX / DRX configuration for the second NTN cell 127. Instead, the cell / beam DTX / DRX configuration(s) for each neighboring cell is provided via system information 1040. For example, the system information 1040 can include a SIB 19 including an NTN-NeighCellConfig IE that includes the cell / beam DTX / DRX configuration of the second NTN cell 127. Therefore, to perform the neighboring cell measurement on the second NTN cell 127, in some implementations, the UE 102 acquires the cell or beam DTX / DRX configuration(s) of the second NTN cell 127, which is / are provided in the NTN-NeighCellConfig IE (within SIB19) containing the Physical Cell Identity (PCI) of second NTN cell 127. At block1072, the UE 102 refrains from measuring the second NTN cell 127 during the OFF period 1097 of the 127 as indicated in the system information 1040.

[0104] FIG. 11 shows a messaging diagram 1100 of an example scenario in which a UE in the idle state determines when to measure a neighboring cell based on the cell / beam DTX / DRX configuration(s) of the neighboring cell included in the system information. In FIG. 11, the UE 102 is in the idle state 1103 and receives the measurement configurations 1120 for the serving cell (i.e., the first NTN cell 126) as well as for the neighboring cell (i.e., the second NTN cell 127) via the system information (i.e., SIB2, SIB3, and SIB4). Similar to the scenario 1000B, the UE 102 also receives a system information 1140 (e.g., SIB 19) including the cell / beam DTX / DRX configuration(s) for the second NTN cell 127. For example, the system information 1140 can include the NTN-NeighCellConfig IE, and the system information 1140 (or another system information message) can provide the cell / beam DTX / DRX configuration(s) for the second NTN cell 127. At block 1 186, the UE 102 may trigger the intra-frequency and / or the inter-frequency measurement on the neighboring cells when the signal quality / strength of the serving cell (i.e., the first NTN cell 126) drops below corresponding threshold values (e.g., S intraSearchQ for triggering the intra-frequency measurement and SnOnintraSearchQ for triggering the inter-frequency measurement).

[0105] However, according to the cell or beam DTX / DRX configuration(s) for the second NTN cell 127, the UE 102 knows that the second NTN cell 127 is currently under an OFF period 1097 and hence is not transmitting any signals including the RSs for the mobility purpose. Therefore, the UE 102 refrains (block 1172) from measuring the second NTN cell 127 while the second NTN cell 127 is in the OFF period 1097. At block 1174, because the second NTN cell 127 has begun the ON period 1098, the UE 102 starts or resumes the measurement on the second NTN cell 127 based on the measurement configuration provided in the event 1120. Based on measurement results of the reference signals (including, for example, the SSB 1185 for idle mode mobility) of the neighbor cell measurement and the serving cell measurement, the UE 102 may trigger (block 1188) a procedure to reselect the second NTN cell 127, as long as the cell reselection criteria for reselecting a neighboring cell (i.e. the section 5.2.4.5 and 5.2.4.6 specified in 3GPP TS 38.104) are fulfilled.

[0106] For clarity, several example methods which the UE 102 or the base station 106 can implement are discussed next with reference to Figs. 12-19B.

[0107] FIG. 12 shows a flow diagram 1200 showing example operations of a UE, in the connected state, managing RLM / BFD measurements based on the cell / beam DTX / DRX configuration(s). Initially, at block 1240, the UE operates in the connected state, and receives from a BS, an RRC message including a DTX / DRX configuration associated with the beam serving the UE, where the DTX / DRX configuration can be only applicable to the beam serving the UE 102, or can be applicable to every beam in the same cell including the serving beam. When the DTX / DRX configuration provided at block 1240 is a beam-specific (i.e., a per-beam basis) configuration, the BS 106 may also provide the DTX / DRX configurations for other beams (other than the serving beam) of the same cell to the UE 102 at block 1240, where each DTX / DRX configuration is associated with either an SSB index or a CSI-RS resource identity.

[0108] In addition to the DTX / DRX configuration for the serving beam, the UE also receives, at block 1250, an RRC message including the RLM / BFD RS resource configuration. Based on the RLM / BFD RS resource configuration, the UE performs, at block 1251 , the RLM and / or the BFD by monitoring / measuring the configured RS resources. In the meantime, the UE may also receive, at block 1245, a DCI activating the DTX / DRX configuration(s) (from block 1240) for the serving beam or for the serving cell.

[0109] Based on the DTX / DRX configuration(s) of the serving beam or the serving cell, at block 1272, the UE stops or suspends the RLM and / or the BFD for the serving beam at the beginning of the OFF period of the serving beam. At block 1274, the UE restarts or resumes the RLM and / or the BFD for the serving beam at the beginning of the ON period of the serving beam. The UE may stop or suspend the entire RLM and / or BFD function if none of the SSBs and / or CSI-RSs configured for the RLM and / or BFD purpose are in the ON period.

[0110] FIG. 13 shows a flow diagram 1300 showing example operations of a UE, in the connected state, managing the RLM / BFD measurements based on the cell / beam DTX / DRX configuration(s) including a status indication for the OFF period. The flow diagram in FIG. 13 is similar to that in FIG. 12, with the differences discussed below. In FIG. 13, block 1341, the UE receives an indication from the BS, as a part of the DTX / DRX configuration of the serving beam, which indicates whether the BS transmits the common control signal (including the RS) in the OFF period of the cell / beam DTX / DRX cycle. At block 1371, the UE checks whether the indication indicates that the BS transmits the common control signal (including the RS for the RLM / BFD purpose) in the OFF period of a cell / beam DTX / DRX cycle. If the determination at the block 1371 is positive (i.e., the BS does transmit the common control signal even in the OFFperiod of a cell / beam DTX / DRX cycle), the flow proceeds to the block 1376, where the UE continues to perform the RLM and / or the BFD on the configured RS resources.[OHl] On the other hand, if the determination at the block 1371 is negative (i.e., the BS does NOT transmit the common control signal in the OFF period of a cell / beam DTX / DRX cycle), the flow proceeds to the block 1272, where the UE stops or suspends the RLM and / or the BFD for the serving beam at the beginning of the OFF period of the serving beam. At block 1274, the UE restarts or resumes the RLM and / or the BFD for the serving beam at the beginning of the ON period of the serving beam.

[0112] FIG. 14 shows a flow diagram showing example operations of a UE, in the connected state, managing when to monitor the RS resources configured for the RLM / BFD based on the UE c-DRX configuration aligning with the cell / beam DTX / DRX configuration. The flow diagram in FIG. 14 is similar to that in FIG. 12, with the differences discussed below. In FIG. 14, in addition to receiving the DTX / DRX configuration(s) for the serving beam / cell and the RS resource configuration for the RLM and / or the BFD purpose, the UE further receives, at block 1460, from the BS, a UE c-DRX configuration including a DRX cycle length whose value is equal to [A * beam / cell DTX / DRX cycle length], where X is an integer greater than 0. At block 1470, the UE 102 then performs the RLM and / or BFD at the time instances based on the RSs configured for the RLM and / or for the BFD purpose, and complies with the minimum timing requirements specified in 3GPP TS 38.133 for the RLM and / or for the BFD operation. As the minimum timing requirements specified in TS 38.133 for the RLM and / or for the BFD operation are based (i.e., proportional to) on the c-DRX cycle length of the UE, the UE performs the RLM and / or the BFD at the time instances based on the UE c-DRX configuration.

[0113] FIG. 15 shows a flow diagram 1500 showing example operations of a UE, in the connected state, managing when to suspend and when to resume the serving cell measurement based on the cell / beam DTX / DRX configuration(s). Initially, at block 1240, the UE operates in the connected state, and receives from a BS, an RRC message including the cell or beam DTX / DRX configuration associated with the beam serving the UE. The UE may also receive at block 1240, the DTX / DRX configurations associated with other beams in the same cell, if the DTX / DRX configuration is a beam-specific configuration. As a part of the cell or beam DTX / DRX configuration, the UE may receive from the BS, at block 1541, an indication indicating that the BS does NOT transmit the common control signal in the OFF period of the cell / beam DTX / DRX cycle. At block 1550, the UE receives an RRC message including a servingcell configuration containing a measurement object configuration for the serving cell. Based on the measurement object configuration for the serving cell, at block 1555 the UE performs the serving cell measurement by measuring the RS resources configured in the measurement object configuration for the serving cell. At some point, the UE may receive, at block 1245, a DCI activating the DTX / DRX configuration(s) that was / were received earlier at block 1240.

[0114] Based on the DTX / DRX configuration(s), at block 1572, the UE stops or suspends the serving cell measurement at the beginning of the OFF period of the serving beam, if the OFF period is common to all the beams of the serving cell, or if the serving beam is the only beam configured to the UE for the serving cell measurement. At block 1574, the UE restarts or resumes the serving cell measurement at the beginning of the ON period of the serving beam.

[0115] FIG. 16 shows a flow diagram 1600 showing example operations of a UE, in the connected state, managing when to perform the serving cell measurement based on the UE c- DRX configuration aligning with the cell or beam DTX / DRX configuration. The flow diagram in FIG. 16 is similar to that in FIG. 15, with the differences discussed below. In FIG. 16, the UE does not receive from the BS the indication indicating the BS does NOT transmit the common control signal in the OFF period of the cell / beam DTX / DRX cycle (i.e., FIG. 16 does not have the block 1541). Instead, in addition to the cell or beam DTX / DRX configuration(s) and the measurement object configuration for the serving cell, the UE receives from the BS, a UE DRX configuration including a DRX cycle length whose value is equal to [A * beam / cell DTX / DRX cycle length], where Xis an integer greater than zero. At block 1670, the UE performs the serving cell measurement at the time instances based on the measurement object configuration for the serving cell and the UE c-DRX configuration (i.e., UE complies with the measurement period requirement defined in 3GPP TS 38.133, which is proportional to the c-DRX cycle length of the UE).

[0116] FIG. 17A shows a flow diagram 1700A showing example operations of a UE, in the connected state, managing when to measure a neighboring cell based on the cell / beam DTX / DRX configuration(s) included in the measurement object configuration for the neighboring cell. Initially, at block 1550, the UE receives from a BS, an RRC message including a serving cell configuration containing a measurement object configuration for the serving cell. The UE also receives, at block 1740A, from the BS, a measurement configuration including a measurement object configuration for a neighbor cell, where the measurement object configuration for the neighbor cell includes a DTX / DRX configuration. In some implementations, the DTX / DRXconfiguration provided at block 1740A is a cell-specific (i.e., a per-cell basis) DTX / DRX configuration that is applicable to all beams of the neighboring cell. In another implementation, the DTX / DRX configuration provided at block 1740A further includes multiple beam-specific DTX / DRX configurations and each beam-specific DTX / DRX configuration is associated with a specific beam in the neighboring cell.

[0117] Based on the measurement object configuration for the serving cell, the UE performs, at block 1555, the serving cell measurement by measuring the RS resources configured in the measurement object configuration for the serving cell. In this example, as the measurement results show that the signal strength / quality of the serving cell is below a specific threshold configured by the network, the UE determines, at block 1746, to trigger the intra-frequency and / or the inter-frequency measurement on the neighboring cells including the neighboring cell configured earlier at the block 1740A. In response to the determination, the UE further checks, at the block 1771 , whether the neighboring cell is currently under an OFF period of a DTX / DRX cycle. If the determination at the block 1771 is positive (i.e., the neighboring cell is currently under an OFF period of a DTX / DRX cycle), the flow proceeds to the block 1772, where the UE refrains from performing the measurement on the neighboring cell. In some implementations, the flow goes from block 1772 the flow returns to block 1746 where the UE determines whether to once again trigger the intra-frequency and / or inter-frequency measurement. A potential technical advantage of this approach is that the UE might avoid measurements of the neighboring cell when the triggering condition is fulfilled for a short period of time covering less than one ON / OFF period and the triggering condition is no longer present after one OFF period of the neighboring cell. Alternatively, from block 1772 the flow might return back to the block 1771 where the UE continuously checks whether to do the neighbor cell measurement (i.e., the ON / OFF status) of the neighboring cell once the intra-frequency and / or inter-frequency measurement has been initially triggered. A potential technical advantage of this approach is that the UE can periodically measure the neighboring cell (i.e., during the ON periods) when the triggering condition spans multiple ON / OFF periods of the neighboring cell to be measured.

[0118] On the other hand, if the determination at block 1771 is negative (i.e., the neighboring cell is not currently under an OFF period of a DTX / DRX cycle), the flow proceeds to the block 1774, where the UE performs the measurement on the neighboring cell. After that, the flow also goes back to the decision block 1771 and the UE needs to check again the status (i.e., the ON / OFF status) of the neighboring cell. Note that the determination at the block 1771 can be made basedon whether all the beams configured for the neighboring cell measurement are under the OFF period. That is, in some implementations, if there is any beam (configured for the neighboring cell measurement) NOT under the OFF period, the UE considers the neighboring cell as not being under the OFF period of a DTX / DRX cycle.

[0119] FIG. 17B shows a flow diagram 1700B showing example operations of a UE, in the connected state, managing when to measure a neighboring cell based on the cell / beam DTX / DRX configuration of the neighboring cell included in the system information. The example method 1700B is generally similar to the example method 1700A, the only difference between them is that in the example method 1700B, the cell or beam DTX / DRX configuration for each neighboring cell is provided at the block 1740B, via the system information rather than via the measurement object configuration (i.e., the measurement object configuration provided at the block 1750 does not contain the cell or beam DTX / DRX configuration(s) for the neighboring cell).

[0120] FIG. 18 shows a flow diagram 1800 showing example operations of a BS (e.g., BS 106 in this disclosure) informing a UE of the DTX / DRX configuration of the serving beam and optionally configuring the UE with a c-DRX configuration aligning with the DTX / DRX configuration of the serving beam. Initially, at block 1840, the BS transmits, to a UE, via a dedicated RRC message or a system information, a DTX / DRX configuration of the beam serving the UE, where the DTX / DRX configuration can be either a beam-specific configuration that is only applicable to the serving beam, or a cell-specific configuration that is applicable to every beam in the same cell (i.e., the serving cell). If the DTX / DRX configuration provided at block 1840 is a beam-specific configuration, the BS may also provide the DTX / DRX configurations for other non-serving beams to the UE at block 1840. The BS may also transmit to the UE, at block 1841, an indication indicating whether the BS will transmit the common control signals including but not limited to the RSs for the RLM / BFD / L3 -mobility purpose during the OFF period of the cell or beam DTX / DRX cycle. The BS may also transmit to the UE, at block 1845, a DCI for activating the DTX / DRX configuration(s) provided at block 1840, where the DCI can be a dedicated DCI (dedicated to the UE) or a group-based DCI (common to a group of UEs). If the BS does not transmit common control signals during the OFF period of the cell or beam DTX / DRX cycle, the BS may also transmit to the UE, at block 1860, a UE c-DRX configuration including a DRX cycle whose length is equal to [X * beam / cell DTX / DRX cycle length], where X is an integer greater than zero.

[0121] FIG. 19A shows a flow diagram 1900A showing example operations of a BS (e.g., BS 106 in this disclosure) for informing the UE of the DTX / DRX configuration of a neighboring cell via the measurement object configuration. Initially, at block 1950, the BS transmits to a UE, an RRC message including a serving cell configuration containing a serving cell measurement object. The BS also transmits, at block 1951 A, to the UE, a measurement configuration including a measurement object configuration for a neighboring cell, where the measurement object configuration for the neighboring cell includes a DTX / DRX configuration associated with the neighboring cell. In some implementations, the DTX / DRX configuration associated with the neighboring cell only contains the DTX configuration. In some implementations, the DTX / DRX configuration associated with the neighboring cell contains multiple DTX / DRX configurations, where each individual DTX / DRX configuration is associated with a beam of the neighboring cell.

[0122] FIG. 19B shows a flow diagram 1900B of an example method that can be implemented by a BS (e g., BS 106 in this disclosure), for informing the UE of the DTX / DRX configuration of a neighboring cell via the system information. The example method 1900B is generally similar to the example method 1900A, the only difference between them is that in the example method 1900B, the DTX / DRX configuration associated with the neighboring cell is provided via the system information (e.g., SIB 19) at block 1940, rather than via the measurement object configuration.

[0123] FIG. 20A shows an example control plane protocol stack 2000A for a regenerative NTN architecture in accordance with aspects of this disclosure. The diagram of the NTN control plane protocol stack 2000A shows the NR-Uu interface (e.g., via a service link) between the satellite 104 (e.g., the BS 106) and the UE 102. The NR-Uu includes a radio resource control (RRC) protocol in addition to the PDCP, RLC, MAC, and PHY layers. The Ng-C interface is between the BS 106 and the CN 110. The example CN 110 in FIG. 20A can illustrate the operation of an access and mobility function (AMF) of the 5GC. In 3GPP standards (e.g., the 3GPP technical specification (TS) 24.501 version 18.4.0), refer to an N1 interface. The diagram of the NTN control plane protocol stack 2000A shows the N 1 interface between the NAS layer of the UE 102 and the NAS layer of the CN 110. The N1 interface links the UE 102 and the AMF of the CN 110 via an access network. In FIG. 20A, the access network includes the NTN (such as the satellite 104, BS 106) coupled by the NTN gateway 108.

[0124] The example illustrated in FIG. 20A shows the BS 106 as a gNB. However, FIG. 20A could be modified to describe a scenario in which the BS 106 is an eNB. The CN 110 can illustrate the operation of a mobility management entity (MME) of an EPC. For example, if the radio access technology for the NTN RAN is E-UTRA or NB-IoT, the Ng-U interface can be referred to as an SI -MME interface. The Nr-Uu can be referred to as an LTE-Uu interface.

[0125] FIG. 20B shows an example control plane protocol stack 2000B for a transparent NTN architecture in accordance with aspects of this disclosure. As with FIG. 20A, the NTN control plane protocol stack 2000B illustrated in FIG. 20B is also similar to that of a terrestrial network (TN), with the addition of the satellite 104 and the NTN gateway 108 being placed in the NR-Uu interface.

[0126] FIG. 21 shows a block diagram of an example wireless communication system 2100 showing hardware features and communication interfaces. The depicted hardware configurations may omit certain components well-understood to be frequently implemented in such electronic devices, such as displays, peripherals, power supplies, and the like. The wireless communication system 2100 includes the same elements as described with reference to FIG. 1, including the UE 102, the BS 106, the satellite 104, and the CN 110. In some implementations, the UE 102 can support at least a 5G NR (or simply, “NR”) or E-UTRA air interface to communicate with the BS 106. The BS 106 connects to the CN 110 via an interface (e.g., SI or NG interface). The BS 106 can connect to other base stations (including the BS 106 or the BS 2108) via an interface (e.g., X2 or Xn interface) for interconnecting NG RAN nodes. In FIG. 21, the BS 2108 operates a TN cell 2109.

[0127] The BS 106 is equipped with processing hardware 2106 that can include a receiver 2116B configured to receive data in the uplink direction. The processing hardware 2106 can also include a transmitter 2116A configured to transmit data in the downlink direction. The processing hardware further can one or more general-purpose processor(s) 2116C (e.g., CPUs) and a non- transitory computer-readable memory (CRM) 2116D storing instructions that the one or more general -purpose processors execute. Additionally, or alternatively, the processing hardware 2106 can include special-purpose processing units. The processor 2116C may include, for example, one or more central processing units, graphics processing units (GPUs), or other application-specific integrated circuits (ASICs), and the like. CRM 2116D may include any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or Flashmemory usable to store device data of the BS 106. The satellite 104 can include processing hardware 2104, such as a transmitter 2114A, a receiver 2114B, a processor 2114C, and CRM 2114D (similar to components 2106, 2116A, 2116B, 2116C and 2116D of the BS 106). In some implementations, the components 2114A, 2114B, 2114C and 2114D are shared or commonly implemented with the components 2116A, 2116B, 2116C and 2116D. The BS 2108 can include generally similar components (not shown) as the processing hardware 2106.

[0128] The UE 102 is equipped with processing hardware 2102 that can include one or more general -purpose processors such as CPUs and non-transitory computer-readable memory 2112D storing machine-readable instructions executable on the one or more general -purpose processors, and / or special -purpose processing units. The processing hardware 2102 can also include a transmitter 2112A configured to transmit data in the uplink direction. The processing hardware further can include a receiver 2112B configured to receive data in the downlink direction. The processing hardware 2102, in an example implementation, includes a processor 21 12C to process data that the UE 102 will transmit in the uplink direction or process data received by UE 102 in the downlink direction. The processor(s) 2112C may include, for example, one or more central processing units, GPUs, or other ASICs, and the like. To illustrate, the processor(s) 2112C may include an application processor (AP) utilized by the UE 102 to execute an operating system and various user-level software applications, as well as one or more processors utilized by modems or a baseband processor. The CRM 2112D may include any suitable memory or storage device such as RAM, SRAM, DRAM, NVRAM, ROM, Flash memory, SSD or other mass-storage devices, and the like useable to store one or more sets of executable software instructions and associated data that manipulate the one or more processor(s) 2112C and other components of the processing hardware 2102 to perform the various functions described herein and attributed to the UE 102. The sets of executable software instructions include, for example, an operating system (OS) and various drivers (not shown), and various software applications (not shown), which are executable by processor(s) 2112C to enable user-plane communication, control-plane signaling, and user interaction with the UE 102.

[0129] The CN 110 can be an Evolved Packet Core (EPC) and / or a 5G core (5GC). Among other components, the EPC can include a Serving Gateway (SGW), a Mobility Management Entity (MME), a Home Subscriber Server (HSS), and a Packet Data Network Gateway (PGW). The SGW in general is configured to transfer user-plane packets related to audio calls, video calls, Internet traffic, etc., and the MME is configured to manage authentication, registration,paging, and other related functions. The PGW provides connectivity from the UE to one or more external packet data networks, e.g., an Internet network and / or an Internet Protocol (IP) Multimedia Subsystem (IMS) network. The 5GC includes a User Plane Function (UPF), a Unified Data Management (UDM), an Access and Mobility Management Function (AMF), and / or Session Management Function (SMF). Generally speaking, the UPF is configured to transfer user-plane packets related to audio calls, video calls, Internet traffic, etc., the AMF is configured to manage authentication, registration, paging, and other related functions, and the SMF is configured to manage PDU sessions. The HSS and the UDM store and maintain subscription information regarding the UE 102. The CN 110 can be implemented by one or more processing elements (shown as processing hardware 2110). The processing hardware 2110 can include a transmitter 2111A, a receiver 211 IB, a processor 2111C, and a CRM 21 HD, similar to corresponding components described with reference to processing hardware 2102, 2104, and 2106.

[0130] The transmitters 2112A, 2114A, 2116A, and 2111A and receivers 2112B, 2114B, 2116B, and 211 IB are examples of a communication unit. The processors 2112C, 2114C, 2116C, and 2111C can also be referred to as a processing system. Other examples of a communication unit and a processing system are possible, including some examples that are commonly used in a wireless communication system. The BS 106, UE 102, satellite 104, and CN 110 can include other components not illustrated in FIG. 21. Similarly, the UE 102 can include a system information interpretation unit capable of interpreting any of the example system information described in this disclosure. The UE 102 can also include an RRC management unit that can operate an RRC INACTIVE or RRC SUSPENDED based on information from the BS 106 to transition to an RRC suspended state. The system information interpretation unit and / or the RRC management unit can be implemented by a processing system and communication unit of the UE 102.

[0131] FIG. 1 through FIG. 21 and the operations described herein are examples meant to aid in understanding example implementations and should not be used to limit the potential implementations or limit the scope of the claims. Some implementations may perform additional operations, fewer operations, operations in parallel or in a different order, and some operations differently.

[0132] Aspects of the subject matter described in this disclosure can be implemented as a computer-readable medium having stored therein instructions which, when executed by aprocessor, causes the processor to perform any one of the above-mentioned functionalities. Aspects of the subject matter described in this disclosure can be implemented as a system having means for implementing any one of the above-mentioned functionalities. Aspects of the subject matter described in this disclosure can be implemented as an apparatus having one or more processors configured to perform one or more operations from the following functionalities (enumerated as clauses for clarity).

[0133] Clause 1 : A method for wireless communication by a user equipment (UE) (102), the method comprising: receiving, from a first non-terrestrial network (NTN) node (101, 104, 106), a connected discontinuous reception (c-DRX) configuration for a connected state of the UE or a cell or beam discontinuous transmission (DTX) or discontinuous reception (DRX) configuration (cell / beam DTX / DRX configuration), the c-DRX or the cell / beam DTX / DRX configuration indicative of an OFF period for a first cell or beam (first cell / beam) of the first NTN node; suspending measurements of downlink reference signals for the first cell / beam during the OFF period; and resuming measurements of the downlink reference signals for the first cell / beam during an ON period following the OFF period.

[0134] Clause 2: The method of clause 1, further comprising: establishing a radio resource control (RRC) connection to the first NTN node via a first beam of the NTN node; and receiving, from the first NTN node, a reference signal (RS) resource configuration for radio link monitoring (RLM) or beam failure detection (BFD) of the first beam, wherein the suspending the measurements includes stopping RLM / BFD of the first beam at a start of the OFF period, and wherein the resuming the measurements includes starting the RLM / BFD of the first beam at a start of the ON period following the OFF period.

[0135] Clause 3 : The method of clause 1 or 2, further comprising: receiving, from the first NTN node, a serving cell configuration (ServingCellConfig) including a serving cell measurement object for a first cell of the first NTN node, wherein the suspending the measurements includes stopping measurements of the serving cell measurement object at a start of the OFF period, and wherein the resuming the measurements includes starting measurements of the serving cell measurement object at a start of the ON period following the OFF period.

[0136] Clause 4: The method of any one of clauses 1 to 3, further comprising: receiving, from the first NTN node, a connected discontinuous reception (c-DRX) configuration for a connected state of the UE, the c-DRX configuration configuring c-DRX active periods and c-DRX inactive periods, wherein the c-DRX active periods have a c-DRX periodicity that is a positive integermultiple (e.g., 1, 2, 3, ...) of a cell / beam DTX periodicity of an ON periodicity defined by the cell / beam DTX / DRX configuration.

[0137] Clause 5: The method of clause 4, wherein the suspending the measurements includes: refraining from monitoring RLM / BFD RSs during the UE c-DRX inactive periods, or refraining from performing serving cell measurements during the c-DRX inactive periods.

[0138] Clause 6: The method of any one of clauses 1 to 5, further comprising: receiving, from the first NTN node, configurations of reference signal (RS) resources associated with at least one additional cell or beam of the first NTN node; wherein the cell / beam DTX / DRX configuration further indicates an OFF period for the at least one additional cell or beam of the first NTN node; and refraining from performing measurements of the RS resources during the OFF period of the at least one additional cell or beam of the first NTN node.

[0139] Clause 7: The method of any one of clauses 1 to 6, further comprising: receiving, from the first NTN node, a neighboring cell DTX / DRX configuration for a neighboring cell, the neighboring cell / beam DTX / DRX configuration indicating OFF periods of the neighboring cell / beam; and refraining from performing measurements of the neighboring cell / beam during the OFF periods of the neighboring cell / beam.

[0140] Clause 8: The method of clause 7, wherein the receiving the neighboring cell / beam DTX / DRX configuration includes receiving the neighboring cell / beam DTX / DRX configuration via: a measurement object configuration (MeasObject) of a measurement configuration (MeasConfy, or a system information block (SIB) signal containing an NTN neighboring cell configurati on (NTN-NeighCellC onfig) .

[0141] Clause 9: The method of clause 7, further comprising: establishing a radio connection with the first NTN node via a serving cell of the first NTN node; and receiving the neighboring cell / beam DTX / DRX configuration via a radio resource control (RRC) message from the serving cell.

[0142] Clause 10: The method of any one of clauses 7 to 9, wherein the neighboring cell / beam is associated with a second NTN node other than the first NTN node.

[0143] Clause 11 : The method of any one of clauses 1 to 10, wherein the OFF period is specified as a period during which the first NTN node will not transmit the downlink reference signals.

[0144] Clause 12: The method of any one of clauses 1 to 11, wherein the OFF period is specified as a period during which the first NTN node optionally transmits the downlink reference signalsas common control signaling, the method further comprising: receiving, from the NTN node, an indication that the first NTN node will not transmit the common control signaling during the OFF period; and suspending the measurements of the downlink reference signals for the first cell / beam during the OFF period based on the indication indicating that the first NTN node will not transmit the common control signaling.

[0145] Clause 13 : A method for wireless communication by a user equipment (UE) (102), the method comprising: receiving, from a first non-terrestrial network (NTN), a neighboring cell or beam discontinuous transmission (DTX) or discontinuous reception (DRX) configuration for a neighboring cell / beam, the neighboring cell / beam DTX / DRX configuration indicating ON periods and OFF periods of the neighboring cell / beam; suspending measurements of downlink reference signals for the neighboring cell / beam during the OFF periods of the neighboring cell / beam; and resuming measurements of the downlink reference signals for the neighboring cell / beam during the ON periods.

[0146] Clause 14: The method of clause 13, wherein the receiving the neighboring cell / beam DTX / DRX configuration includes receiving the neighboring cell / beam DTX / DRX configuration via: a measurement object configuration (MeasObjecf) of a measurement configuration (MeasConf),' or a system information block (SIB) signal containing an NTN neighboring cell configuration (NTN-NeighCellConfig) .

[0147] Clause 15: A method for wireless communication by a non-terrestrial network (NTN) node (101, 104, 106), the method comprising: transmitting, to a user equipment (UE) (102), a cell or beam discontinuous transmission (DTX) or discontinuous reception (DRX) configuration (cell / beam DTX / DRX configuration) indicating an OFF period for a first cell or beam (first cell / beam) of the NTN node; and causing the UE to suspend measurements of downlink reference signals for the first cell / beam during the OFF period.

[0148] Clause 16: The method of clause 15, further comprising: transmitting, to the UE, a connected discontinuous reception (c-DRX) configuration 1670 for a connected state, the c-DRX configuration configuring UE c-DRX active periods and UE c-DRX inactive periods, wherein the c-DRX active periods have a UE c-DRX periodicity that is a positive integer multiple (e.g., 1, 2, 3, ...) of a cell / beam DTX periodicity of an ON period defined by the cell / beam DTX / DRX configuration.

[0149] Clause 17: The method of 6, further comprising: transmitting, to the UE, a neighboring cell DTX / DRX configuration for a neighboring cell, the neighboring cell / beam DTX / DRXconfiguration indicating OFF periods of the neighboring cell / beam, wherein the transmitting the neighboring cell / beam DTX / DRX configuration includes transmitting the neighboring cell / beam DTX / DRX configuration via: a measurement object configuration (MeasObject) of a measurement configuration MeasConfy, or a system information block (SIB) signal containing an NTN neighboring cell configuration (NTN-NeighCellConfig).

[0150] Clause 18: The method of clause 17, further comprising: establishing a radio connection with the UE via a serving cell of the NTN node; and transmitting the neighboring cell / beam DTX / DRX configuration via a radio resource control (RRC) message from the serving cell.

[0151] Clause 19: The method of any one of clauses 15 to 18, wherein the OFF period is specified as a period during which the NTN node optionally transmits the downlink reference signals as common control signaling, the method further comprising: transmitting, to the UE, an indication indicating whether the NTN node will transmit or will not transmit the common control signaling during the OFF period.

[0152] Clause 20: An apparatus, comprising: a communication unit; and a processing system configured to control the communication unit to implement any one of the methods of any one of clauses 1 to 19.

[0153] The following additional considerations may apply to the foregoing and the following discussions. Generally speaking, description for one of the above figures can apply to another of the above figures. Any event or block described above can be optional. For example, an event or block with dashed lines can be optional. In some implementations, “message” is used and can be replaced by “information element (IE),” and vice versa. In some implementations, “IE” is used and can be replaced by “field,” and vice versa. In some implementations, “configuration” can be replaced by “configurations” or “configuration parameters,” and vice versa. In some implementations, “some” means “one or more.” In some implementations, “at least one” means “one or more.” The “eNB” can be replaced by “base station,” “gNB,” “6G base station,” “evolved gNB,” or 6G gNB. “MME” can be replaced by AMF or evolved AMF or 6G AMF. “Core network (CN)” can be replaced by EPC, 5GC or 6GC.

[0154] Some examples of this disclosure refer to RRC messages for illustrative purposes. In the various figures and descriptions, some RRC messages can be replaced by other examples. For example, “RRC Connection Request message” can be replaced by “RRC Setup Request message.” “RRC Connection Setup message” can be replaced by “RRC Setup message.” “RRC Connection Setup Complete message” can be replaced by “RRC Setup Complete message.”“RRC Connection Reconfiguration message” can be replaced by “RRC Reconfiguration message.” “RRC Connection Reestablishment Request message” can be replaced by “RRC Reestablishment Request message.” “RRC Connection Reestablishment message” can be replaced by “RRC Reestablishment message.” “RRC Connection Reestablishment Complete message” can be replaced by “RRC Reestablishment Complete message.” “RRC Connection Resume Request message” can be replaced by “RRC Resume Request message.” “RRC Connection Resume message” can be replaced by “RRC Resume message.” “RRC Connection Resume Complete message” can be replaced by “RRC Resume Complete message.” “NAS Attach Request message” or “TAU Request message” can be replaced by “Registration Request message.” “NAS Attach Accept message” or “TAU Accept message” can be replaced by “Registration Accept message.”

[0155] Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this specification belongs. The terms “first,” “second,” and the like, as used herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The use of terms “including,” “comprising” or “having” and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “connected” and “coupled” are not restricted to physical or mechanical connections or couplings and can include electrical connections or couplings, whether direct or indirect. Furthermore, terms “circuit” and “circuitry” and “control unit” may include either a single component or a plurality of components, which are either active and / or passive and are connected or otherwise coupled together to provide the described function. In addition, the term operationally coupled as used herein includes wired coupling, wireless coupling, electrical coupling, magnetic coupling, radio communication, software based communication, or combinations thereof.

[0156] Some or all of the foregoing or the following implementations can be jointly combined or formed to be a new implementation. The foregoing or the following techniques can be used to solve at least (but not limited to) the issue(s) or scenario(s) mentioned in this disclosure. Any two or more than two of the foregoing or the following paragraphs, (sub)-bullets, points, actions, or claims described in each method / technique / implementation may be combined logically, reasonably, and properly to form a specific method. Any sentence, paragraph, (sub)-bullet, point, action, or claim described in each of the foregoing or the followingtechnique(s) / implementation(s) / concept(s) may be implemented independently and separately to form a specific method. Dependency, such as “based on,” “more specifically,” “where” or etc., in technique(s) / implementation(s) / concept(s) mentioned in this disclosure is just one possible implementation which would not restrict the specific method.

[0157] As used herein, the terms “user device”, “user equipment” (for example, UE 102), “wireless communication device”, “mobile communication device”, “communication device”, or “mobile device” refer to any one or all of cellular telephones, smartphones, portable computing devices, personal or mobile multi-media players, laptop computers, tablet computers, smartbooks, Internet-of-Things (loT) devices, palm-top computers, wireless electronic mail receivers, multimedia Internet enabled cellular telephones, wireless gaming controllers, display sub-systems, driver assistance systems, vehicle controllers, vehicle system controllers, vehicle communication system, infotainment systems, vehicle telematics systems or subsystems, vehicle display systems or subsystems, vehicle data controllers, point-of-sale (POS) terminals, health monitoring devices, drones, cameras, media-streaming dongles or another personal media devices, wearable devices such as smartwatches, wireless hotspots, femtocells, broadband routers or other types of routers, and similar electronic devices which include a programmable processor and memory and circuitry configured to perform operations as described herein. Further, the user device in some cases may be embedded in an electronic system such as the head unit of a vehicle or an advanced driver assistance system (ADAS). Still further, the user device can operate as an internet-of-things (loT) device or a mobile-internet device (MID). Depending on the type, the user device can include one or more general -purpose processors, a computer-readable memory, a user interface, one or more network interfaces, one or more sensors, etc.

[0158] Certain techniques are described in this disclosure as including logic or a number of components or modules. Modules can be software modules {e.g., code, or machine-readable instructions stored on non-transitory machine-readable medium) or hardware modules. A hardware module is a tangible unit capable of performing certain operations and may be configured or arranged in a certain manner. A hardware module can comprise dedicated circuitry or logic that is permanently configured {e.g., as a special-purpose processor, such as a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC), a digital signal processor (DSP), etc.) to perform certain operations. A hardware module may also comprise programmable logic or circuitry {e.g., as encompassed within a general -purpose processor or other programmable processor) that is temporarily configured by software toperform certain operations. The decision to implement a hardware module in dedicated and permanently configured circuitry, or in temporarily configured circuitry (e.g., configured by software) may be driven by cost and time considerations.

[0159] When implemented in software, the techniques can be provided as part of the operating system, a library used by multiple applications, a particular software application, etc. The software can be executed by one or more general-purpose processors or one or more specialpurpose processors.

[0160] As used herein, the terms “component” and “module” are intended to be broadly construed as hardware, firmware, or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, or a combination of hardware and software. As used herein, the phrase “based on” is intended to be broadly construed to mean “based at least in part on.”

[0161] As used herein, a phrase referring to a list of items separated by “or” refers to any combination of those items, including single members. For example, “a, b, or c” is intended to cover the possibilities of: a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a and b and c.

[0162] In this disclosure, an expression of “X / Y” may mean any of the following: “X or Y” or “X and Y” or “X and / or Y." An expression of “(A) B” or “B (A)” may include the concept of “only B.” An expression of “(A) B” or “B (A)” may include the concept of “A+B” or “B+A.”

[0163] In this disclosure, the term "can" indicates a capability, or alternatively indicates a possible implementation option. The term "may" indicates a permission or a possible implementation option.

[0164] Some aspects are described herein in connection with thresholds. As used herein, satisfying a threshold may refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, or the like.

[0165] The various illustrative components, logic, logical blocks, modules, circuits, operations and algorithm processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, firmware, software, or combinations of hardware, firmware or software, including the structures disclosed in this specification and the structural equivalents thereof. The interchangeability of hardware, firmware and software has been described generally, in terms of functionality, and illustrated in the various illustrativecomponents, blocks, modules, circuits and processes described above. Whether such functionality is implemented in hardware, firmware or software depends upon the particular application and design constraints imposed on the overall system.

[0166] As described above, some aspects of the subject matter described in this specification can be implemented as software. For example, various functions of components disclosed herein, or various blocks or steps of a method, operation, process or algorithm disclosed herein can be implemented as one or more modules of one or more computer programs. Such computer programs can include non-transitory processor-executable or computer-executable instructions encoded on one or more tangible processor-readable or computer-readable storage media for execution by, or to control the operation of, a data processing apparatus including the components of the devices described herein. By way of example, and not limitation, such storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to store program code in the form of instructions or data structures. Combinations of the above should also be included within the scope of storage media.

[0167] Various modifications to the implementations described in this disclosure may be readily apparent to persons having ordinary skill in the art, and the generic principles defined herein may be applied to other implementations without departing from the scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.

[0168] Additionally, various features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. As such, although features may be described above as acting in particular combinations, and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

[0169] The drawings may schematically depict one or more example processes in the form of a flowchart or flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additionaloperations can be performed before, after, simultaneously, or between any of the illustrated operations. In some circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.

[0170] The foregoing disclosure provides illustration and description but is not intended to be exhaustive or to limit the aspects to the precise form disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects. While the aspects of the disclosure have been described in terms of various examples, any combination of aspects from any of the examples is also within the scope of the disclosure. The examples in this disclosure are provided for pedagogical purposes.

Claims

CLAIMSWhat is claimed is:

1. A method for wireless communication by a user equipment (UE) (102), the method comprising: receiving, from a first non-terrestrial network (NTN) node (101, 104, 106), a connected discontinuous reception (c-DRX) configuration for a connected state of the UE, the c-DRX configuration indicative of an OFF period for a first cell or beam (first cell / beam) of the first NTN node; suspending measurements of downlink reference signals for the first cell / beam during the OFF period; and resuming measurements of the downlink reference signals for the first cell / beam during an ON period following the OFF period.

2. The method of claim 1, further comprising: establishing a radio resource control (RRC) connection to the first NTN node via a first beam of the NTN node; and receiving, from the first NTN node, a reference signal (RS) resource configuration for radio link monitoring (RLM) or beam failure detection (BFD) of the first beam, wherein the suspending the measurements includes stopping RLM / BFD of the first beam at a start of the OFF period, and wherein the resuming the measurements includes starting the RLM / BFD of the first beam at a start of the ON period following the OFF period.

3. The method of claim 1 or 2, further comprising: receiving, from the first NTN node, a serving cell configuration (ServingC ellConfig) including a serving cell measurement object for a first cell of the first NTN node, wherein the suspending the measurements includes stopping measurements of the serving cell measurement object at a start of the OFF period, and wherein the resuming the measurements includes starting measurements of the serving cell measurement object at a start of the ON period following the OFF period.

4. The method of any one of claims 1 to 3, wherein: the c-DRX configuration configures c-DRX active periods and c-DRX inactive periods, and the c-DRX active periods have a c-DRX periodicity that is a positive integer multiple (e.g., 1, 2, 3, ...) of a cell / beam DTX periodicity of an ON period.

5. The method of any one of claims 1, 3, or 4, wherein the suspending the measurements includes: refraining from monitoring RLM / BFD RSs during the c-DRX inactive periods, or refraining from performing serving cell measurements during the c-DRX inactive periods.

6. The method of any one of claims 1 to 5, further comprising: receiving, from the first NTN node, configurations of reference signal (RS) resources associated with at least one additional cell or beam of the first NTN node; wherein the c-DRX configuration further indicates an OFF period for the at least one additional cell or beam of the first NTN node; and refraining from performing measurements of the RS resources during the OFF period of the at least one additional cell or beam of the first NTN node.

7. The method of any one of claims 1 to 6, further comprising: receiving, from the first NTN node, a neighboring cell DTX / DRX configuration for a neighboring cell of the first NTN node or a second NTN node, the neighboring cell / beam DTX / DRX configuration indicating OFF periods of the neighboring cell / beam; and refraining from performing measurements of the neighboring cell / beam during the OFF periods of the neighboring cell / beam.

8. The method of claim 7, wherein the receiving the neighboring cell / beam DTX / DRX configuration includes receiving the neighboring cell / beam DTX / DRX configuration via: a measurement object configuration (MeasObjecf) of a measurement configurationMeasConf or a system information block (SIB) signal containing an NTN neighboring cell configuration (NTN-NeighCellConfig) .

9. The method of any one of claims 1 to 8, wherein the OFF period is specified as a period during which the first NTN node will not transmit the downlink reference signals.

10. The method of any one of claims 1 to 9, wherein the OFF period is specified as a period during which the first NTN node optionally transmits the downlink reference signals as common control signaling, the method further comprising: receiving, from the NTN node, an indication that the first NTN node will not transmit the common control signaling during the OFF period; and suspending the measurements of the downlink reference signals for the first cell / beam during the OFF period based on the indication indicating that the first NTN node will not transmit the common control signaling.

11. A method for wireless communication by a non-terrestrial network (NTN) node (101, 104, 106), the method comprising: transmitting, to a user equipment (UE) (102), a connected discontinuous reception (c- DRX) configuration for a connected state of the UE, the c-DRX configuration indicative of an OFF period for a first cell or beam (first cell / beam) of the NTN node; and causing the UE to suspend measurements of downlink reference signals for the first cell / beam during the OFF period based on the c-DRX configuration.

12. The method of claim 11, wherein: the c-DRX configuration configures UE c-DRX active periods and UE c-DRX inactive periods, and the c-DRX active periods have a UE c-DRX periodicity that is a positive integer multiple (e.g., 1, 2, 3, ...) of a cell / beam DTX periodicity of an ON period.

13. The method of claim 11 or 12, further comprising: transmitting, to the UE, a neighboring cell DTX / DRX configuration for a neighboring cell, the neighboring cell / beam DTX / DRX configuration indicating OFF periods of the neighboring cell / beam, wherein the transmitting the neighboring cell / beam DTX / DRX configuration includes transmitting the neighboring cell / beam DTX / DRX configuration via: a measurement object configuration (MeasObjecf) of a measurement configuration (MeasConf),' or a system information block (SIB) signal containing an NTN neighboring cell configuration (NTN-NeighCellConfig).

14. The method of any one of claims 11 to 13, wherein the OFF period is specified as a period during which the NTN node optionally transmits the downlink reference signals as common control signaling, the method further comprising: transmitting, to the UE, an indication indicating whether the NTN node will transmit or will not transmit the common control signaling during the OFF period.

15. An apparatus, comprising: a communication unit; and a processing system configured to control the communication unit to implement any one of the methods of claims 1 to 14.

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