NTN entities, user equipment, and base stations involved in the transmission procedure

Abstract

The present disclosure relates to an NTN entity comprising: a receiver unit of the NTN entity receives a channel condition report from a user equipment (UE), the channel condition report providing information about a channel between the UE and the NTN entity; a transmitter unit of the NTN entity forwards the received channel condition report to a base station; the receiver unit receives scheduling information from the base station regarding downlink or uplink transmission of data at the UE; a processor unit of the NTN entity determines updated channel conditions; the processor determines, based on the updated channel conditions, whether to adapt transmit power for downlink or uplink transmission according to the received scheduling information; and, if the processor determines to adapt transmit power, adapts the transmit power for downlink or uplink transmission.

Description

[Technical Field]

[0001] The present disclosure relates to methods, apparatus, and articles in communication systems, such as 3GPP (registered trademark; hereinafter the same) communication systems. [Background technology]

[0002] Currently, the 3rd Generation Partnership Project (3GPP) is working on technical specifications for the next generation of cellular technology, also known as the fifth generation (5G).

[0003] One objective is to provide a single technical framework that addresses all usage scenarios, requirements, and deployment scenarios (see, for example, Section 6 of Non-Patent Document 1), including at least enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC). For example, deployment scenarios for eMBB may include indoor hotspots, dense urban areas, suburban areas, and urban macro-high-speed environments. Deployment scenarios for URLLC may include industrial control systems, mobile health management (remote monitoring, remote diagnosis, and remote treatment), real-time vehicle control, and wide-area monitoring and control systems for smart grids. Deployment scenarios for mMTC may include scenarios using a large number of devices, such as smart wearables and sensor networks, where the impact of data transmission delays is small. While eMBB and URLLC services are similar in that they both require extremely high bandwidth, URLLC services differ in that they may preferably require extremely low latency.

[0004] A second objective is to achieve forward compatibility: backward compatibility to Long Term Evolution (LTE, LTE-A) cellular systems is not required, which facilitates the design of entirely new systems and / or the introduction of new features. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] TR 38.913 version 16.0.0 [Non-patent document 2] 3GPP TS 38.300 v16.3.0 [Non-patent document 3] 3GPP TS 38.211 v16.3.0 [Non-patent document 4] ITU-R M.20183 [Non-Patent Document 5] TS 23.501 v16.6.0 [Non-patent document 6] 3GPP TR 38.811 [Non-Patent Document 7] 3GPP TR 38.821 [Non-patent document 8] TR 38.321 [Non-Patent Document 9] TS 38.401 Summary of the Invention

[0006] One non-limiting exemplary embodiment serves to provide a procedure for facilitating NTN entity participation in improved transmission procedures.

[0007] In one embodiment, the technology disclosed herein features a Non-Terrestrial Network (NTN) entity comprising: a receiver unit of the NTN entity receives, from a user equipment (UE), a channel condition report providing information about a channel between the UE and the NTN entity; a transmitter unit of the NTN entity forwards the received channel condition report to a base station; the receiver unit receives, from the base station, scheduling information related to downlink or uplink transmission of data at the UE; a processor unit of the NTN entity determines updated channel conditions; and, based on the updated channel conditions, the processor determines whether to adapt a transmit power for a downlink or uplink transmission according to the received scheduling information. If the processor determines to adapt the transmit power, the processor adapts the transmit power for the downlink or uplink transmission.

[0008] It should be noted that the general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any combination thereof. For example, the integrated circuit may control processing of a UE or a base station.

[0009] Further benefits and advantages of the disclosed embodiments and various implementations will become apparent from the specification and drawings. These benefits and / or advantages may be obtained individually by the various embodiments and features of the specification and drawings, and it is not necessary for all embodiments and features to be present in order to obtain one or more of such benefits and / or advantages. [Brief explanation of the drawings]

[0010] In the following, exemplary embodiments are explained in more detail with reference to the accompanying drawings. [Figure 1] FIG. 1 illustrates an example architecture of a 3GPP NR system. [Figure 2] Schematic diagram showing functional separation between NG-RAN and 5GC [Figure 3] Sequence diagram of RRC connection setup / reconfiguration procedure [Figure 4] Schematic showing enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low-latency communications (URLLC) usage scenarios [Figure 5] Block diagram illustrating an exemplary 5G system architecture for a non-roaming scenario [Figure 6] An exemplary transparent satellite-based NG RAN architecture [Figure 7] Exemplary NG RAN Architecture Based on Regenerative Satellites [Figure 8] FIG. 1 illustrates an exemplary scenario in which several UEs are served by a satellite. [Figure 9] Diagram showing an exemplary and simplified structure of UE, gNB and NTN entities [Figure 10] FIG. 1 illustrates the structure of an NTN entity according to an exemplary implementation of an improved transmission procedure. [Figure 11] Flow diagram of NTN entity behavior according to an exemplary implementation of the improved transmission procedure. [Figure 12] FIG. 1 illustrates the structure of a UE according to an exemplary implementation of an improved transmission procedure. [Figure 13] Flow diagram of UE behavior according to an exemplary implementation of the improved transmission procedure [Figure 14] FIG. 1 illustrates the structure of a base station according to an exemplary implementation of an improved transmission procedure. [Figure 15] Flow diagram of base station behavior according to an exemplary implementation of an improved transmission procedure [Figure 16] 1 illustrates a general and simplified message exchange between a UE, a satellite, and a gNB for an improved transmission procedure in the downlink. [Figure 17] 1 illustrates a general and simplified message exchange between a UE, a satellite, and a gNB in ​​various variants of an improved transmission procedure in the downlink. [Figure 18]Diagram showing transmit power adaptation for three UEs [Figure 19] FIG. 1 illustrates a general and simplified message exchange between a UE, a satellite, and a gNB in ​​an improved transmission procedure in the uplink according to a first variant. [Figure 20] FIG. 1 illustrates a general and simplified message exchange between a UE, a satellite, and a gNB according to a first implementation of a first variant. [Figure 21] FIG. 1 illustrates a general and simplified message exchange between a UE, a satellite, and a gNB in ​​an improved transmission procedure in the uplink according to a second variant. [Figure 22] FIG. 1 illustrates a general and simplified message exchange between a UE, a satellite, and a gNB according to an implementation of a second variant. [Figure 23] FIG. 1 shows a general variant of an improved transmission procedure in which a nearby satellite decodes an updated channel condition report. DETAILED DESCRIPTION OF THE INVENTION

[0011] <5G NR system architecture and protocol stack> 3GPP continues to work on the next release of fifth-generation cellular technology (also known as simply "5G"), which includes the development of New Radio Access Technology (NR) operating in the frequency range up to 100 GHz. The first version of the 5G standard was completed in late 2017, allowing for the prototyping and commercial deployment of 5G NR-compliant smartphones.

[0012] In particular, the system architecture as a whole assumes an NG-RAN (Next Generation - Radio Access Network) comprising gNBs. The gNBs provide UE-side termination of NG radio access user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocols. The gNBs are connected to each other via an Xn interface. The gNBs are also connected to an NGC (Next Generation Core) via a Next Generation (NG) interface, more specifically to an AMF (Access and Mobility Management Function) (e.g., a specific core entity that performs AMF) via an NG-C interface, and to a UPF (User Plane Function) (e.g., a specific core entity that performs UPF) via an NG-U interface. The NG-RAN architecture is shown in Figure 1 (see, for example, Section 4 of Non-Patent Document 2).

[0013] The NR user plane protocol stack (see, for example, Section 4.4.1 of Non-Patent Document 2) includes a Packet Data Convergence Protocol (PDCP) sublayer (see, for example, Section 6.4 of Non-Patent Document 2), a Radio Link Control (RLC) sublayer (see, for example, Section 6.3 of Non-Patent Document 2), and a Medium Access Control (MAC) sublayer (see, for example, Section 6.2 of Non-Patent Document 2), which are terminated on the network side at the gNB. A new Access Stratum (AS) sublayer (Service Data Adaptation Protocol (SDAP)) is introduced on top of PDCP (see, for example, Section 6.5 of Non-Patent Document 2). A control plane protocol stack is also defined for NR (see, for example, Section 4.4.2 of Non-Patent Document 2). An overview of Layer 2 functions is described in Section 6 of Non-Patent Document 2. RRC layer functions are listed in Section 7 of Non-Patent Document 2.

[0014] For example, the Medium-Access-Control layer handles logical channel multiplexing and scheduling and scheduling-related functions, including handling various numerologies.

[0015] For example, the physical layer (PHY) is responsible for coding, PHY HARQ processing, modulation, multi-antenna processing, and mapping of signals to appropriate physical time-frequency resources. The physical layer also handles mapping of transport channels to physical channels. The physical layer provides services to the MAC layer in the form of transport channels. A physical channel corresponds to a set of time-frequency resources used for transmitting a specific transport channel, and each transport channel is mapped to a corresponding physical channel. For example, physical channels include the Physical Random Access Channel (PRACH), the Physical Uplink Shared Channel (PUSCH), and the Physical Uplink Control Channel (PUCCH) as uplink physical channels, and the Physical Downlink Shared Channel (PDSCH), the Physical Downlink Control Channel (PDCCH), and the Physical Broadcast Channel (PBCH) as downlink physical channels.

[0016] NR use cases / deployment scenarios may include enhanced mobile broadband (eMBB), ultra-reliable and low-latency communications (URLLC), and massive machine-type communications (mMTC), which have diverse requirements in terms of data rate, latency, and coverage. For example, eMBB is expected to support peak data rates (20 Gbps in the downlink and 10 Gbps in the uplink) and effective (user-experienced) data rates that are approximately three times higher than those offered by IMT-Advanced. For URLLC, on the other hand, more stringent requirements are placed on ultra-low latency (0.5 ms for user plane latency in both UL and DL) and high reliability (1-10 Mbps within 1 ms). -5 Finally, mMTC is preferably designed for high connection density (1,000,000 devices / km in urban environments). 2 ), wide coverage in adverse environments, and extremely long battery life (15 years) for low-cost devices may be desired.

[0017] Therefore, OFDM numerology (e.g., subcarrier spacing, OFDM symbol length, cyclic prefix (CP) length, number of symbols per scheduling interval) suitable for one use case may not be valid for another use case. For example, low-latency services may preferably require a shorter symbol length (and therefore a larger subcarrier spacing) and / or fewer symbols per scheduling interval (also called TTI) than mMTC services. Furthermore, deployment scenarios with large channel delay spreads may preferably require a longer CP length than scenarios with small delay spreads. Subcarrier spacing should be optimized accordingly to maintain similar CP overhead. NR may support one or more subcarrier spacing values. Therefore, subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, etc. are currently considered. Symbol length T u and the subcarrier spacing Δf is given by the formula Δf=1 / T uSimilar to LTE systems, the term "resource element" can be used to mean the smallest resource unit consisting of one subcarrier for the length of one OFDM / SC-FDMA symbol.

[0018] In the new radio system 5G-NR, a resource grid of subcarriers and OFDM symbols is defined for each numerology and each carrier in the uplink and downlink, respectively. Each element of the resource grid is called a resource element and is identified based on a frequency index in the frequency domain and a symbol position in the time domain (see Non-Patent Document 3 (e.g., Section 4)). For example, downlink and uplink transmissions are configured as frames with a duration of 10 ms. Each frame consists of 10 subframes, each with a duration of 1 ms. In a 5G NR implementation, the number of consecutive OFDM symbols per subframe depends on the subcarrier spacing setting. For example, with a subcarrier spacing of 15 kHz, a subframe has 14 OFDM symbols (similar to an LTE-compliant implementation, assuming a normal cyclic prefix). On the other hand, with a subcarrier spacing of 30 kHz, a subframe has two slots, each with 14 OFDM symbols.

[0019] <Functional separation between NG-RAN and 5GC in 5G NR> Figure 2 shows the functional separation between NG-RAN and 5GC. The logical node of NG-RAN is gNB or ng-eNB. 5GC has logical nodes AMF, UPF, and SMF.

[0020] In particular, the gNB and ng-eNB host the following main functions: - Radio Resource Management functions such as Radio Bearer Control, Radio Admission Control, Connection Mobility Control, dynamic allocation (scheduling) of resources to UEs in both uplink and downlink; - IP header compression, encryption, and integrity protection of data; - AMF selection at UE attach time if routing to the AMF cannot be determined from information provided by the UE; - Routing of user plane data towards UPF; - Routing of control plane information towards AMF; - Connection setup and release; - scheduling and sending of paging messages; - Scheduling and transmission of system broadcast information (originating from AMF or Operation, Admission, and Maintenance Function (OAM)); - Setting up measurements and reporting of measurements for mobility and scheduling; - Transport level packet marking in the uplink; - Session management; - Network slicing support; - QoS flow management and mapping to data radio bearers; - Support for UEs in RRC_INACTIVE state; - Non-Access Stratum (NAS) message delivery functions; - Sharing of radio access networks; - Dual connectivity; - Close cooperation between NR and E-UTRA.

[0021] The Access and Mobility Management Function (AMF) hosts the following main functions: - Terminating Non-Access Stratum (NAS) signaling; - NAS signaling security; - Access Stratum (AS) security controls; - 3GPP Core Network (CN) inter-node signaling for mobility between access networks; - Reachability to idle mode UEs (including control and execution of paging retransmissions); - Managing the registration area; - Support for intra-system and inter-system mobility; - Access authentication; - Access authorization, including checking roaming privileges; - Mobility management control (subscription and policy); - Network slicing support; - Selection of Session Management Function (SMF).

[0022] Additionally, the User Plane Function (UPF) hosts the following main functions: - Anchor points for intra-RAT / inter-RAT mobility (if applicable); - External PDU (Protocol Data Unit) session points for interconnection with data networks; - Packet routing and forwarding; - Packet inspection and policy rule enforcement for the user plane; - Traffic usage reporting; - uplink classifier that supports routing of traffic flows to the data network; - Branching Point for supporting multi-homed PDU sessions; - QoS processing for the user plane (e.g., packet filtering, gating, UL / DL rate enforcement); - Verification of uplink traffic (mapping to QoS flows of SDFs); - Downlink packet buffering and triggering function for downlink data notification.

[0023] Finally, the Session Management Function (SMF) hosts the following main functions: - Session management; - IP address allocation and management for the UE; - Selection and control of the UPF; - Traffic steering setting function in the User Plane Function (UPF) for routing traffic to the appropriate destination; - Policy enforcement and QoS in the control part; - Notification of downlink data.

[0024] <Procedures for RRC connection setup and reconfiguration> Figure 3 shows some of the interactions between the UE, gNB, and AMF (5GC entity) when the UE transitions from RRC_IDLE to RRC_CONNECTED in the NAS part (see Non-Patent Document 2).

[0025] RRC is a higher layer signaling protocol used to configure the UE and the gNB. In particular, with this transition, the AMF prepares UE context data (including, for example, PDU session context, security keys, UE radio capabilities, and UE security capabilities) and sends it to the gNB with an INITIAL CONTEXT SETUP REQUEST. The gNB then activates AS security together with the UE. This is done by the gNB sending a SecurityModeCommand message to the UE, and the UE responding with a SecurityModeComplete message. The gNB then sends an RRCReconfiguration message to the UE, and upon receiving an RRCReconfigurationComplete from the UE, the gNB reconfigures the UE to set up a Signaling Radio Bearer 2 (SRB2) and a Data Radio Bearer (DRB). For signaling-only connections, the RRCReconfiguration steps are omitted because SRB2 and DRB are not set up. Finally, the gNB notifies the AMF that the setup procedure is complete with an INITIAL CONTEXT SETUP RESPONSE.

[0026] Therefore, the present disclosure provides a 5th Generation Core (5GC) entity (e.g., AMF, SMF, etc.) that includes: control circuitry that, in operation, establishes a Next Generation (NG) connection with a gNodeB; and a transmitter that, in operation, transmits an initial context setup message to the gNodeB via the NG connection so that a signaling radio bearer between the gNodeB and a user equipment (UE) is set up. Specifically, the gNodeB transmits Radio Resource Control (RRC) signaling, including a resource allocation configuration information element (IE), to the UE via the signaling radio bearer. Then, the UE performs uplink transmission or downlink reception based on the resource allocation configuration.

[0027] <IMT usage scenarios from 2020 onwards> Figure 4 illustrates some use cases for 5G NR. The 3rd Generation Partnership Project New Radio (3GPP NR) is considering three use cases envisioned by IMT-2020 to support a wide variety of services and applications. The first phase of specifications for enhanced mobile broadband (eMBB) has been completed. Current and future work includes standardization for ultra-reliable and low-latency communications (URLLC) and massive machine-type communications (mMTC), in addition to expanding support for eMBB. Figure 4 illustrates some examples of expected usage scenarios for IMT beyond 2020 (see, for example, Figure 2 in Non-Patent Document 4).

[0028] URLLC use cases have stringent performance requirements such as throughput, latency, and availability, and are envisioned as one of the enablers of future applications such as wireless control of industrial production or manufacturing processes, remote medical surgery, automated power transmission and distribution in smart grids, and road safety. URLLC's ultra-high reliability is supported by identifying technologies that meet the requirements set by NR URLLC in Release 15. Key requirements for NR URLLC in Release 15 include a target user plane latency of 0.5 ms on the uplink (UL) and 0.5 ms on the downlink (DL). A typical URLLC requirement for a single packet transmission is a block error rate (BLER) of 1E-5 for a 32-byte packet size with a user plane latency of 1 ms.

[0029] From a physical layer perspective, reliability can be improved in many possible ways. Current reliability improvement room includes defining a separate CQI table for URLLC, a more compact DCI format, repeated transmission of PDCCH, etc. However, this room can be expanded to achieve ultra-high reliability as NR (with respect to the key requirements of NR URLLC) becomes more stable and developed. Specific use cases for NR URLLC in Release 15 include augmented reality / virtual reality (AR / VR), e-health, e-safety, and mission-critical applications.

[0030] Additionally, technology enhancements targeted by NR URLLC aim to improve latency and reliability. Technology enhancements for latency improvement include configurable numerology, non-slot-based scheduling with flexible mapping, grant-free (configured grant) uplink, slot-level repeated transmission in the data channel, and preemption in the downlink. Preemption means that a transmission with already allocated resources is stopped and the allocated resources are used for another transmission with a later requested lower latency / higher priority requirement. Thus, a previously allowed transmission is preempted by a later transmission. Preemption is applicable regardless of the specific service type. For example, a transmission of service type A (URLLC) can be preempted by a transmission of service type B (eMBB, etc.). Technology enhancements for reliability improvement include dedicated CQI / MCS tables for a target BLER of 1E-5.

[0031] The use case for massive machine-type communication (mMTC) is characterized by a very large number of connected devices that typically transmit relatively small amounts of data that are not sensitive to latency. These devices are required to be low cost and have very long battery life. From an NR perspective, using very narrow bandwidth portions is one solution that saves power and allows for long battery life for the UE.

[0032] As mentioned above, the scope of reliability improvement in NR is expected to become broader. One of the key requirements for all cases, especially for URLLC and mMTC, is high or ultra-high reliability. Several mechanisms can improve reliability from the radio perspective and the network perspective. Generally, there are two to three key areas that can help improve reliability. These areas include compact control channel information, repeated transmission of data channels / control channels, and diversity in the frequency, time, and / or spatial domains. These areas are generally applicable to reliability improvement regardless of the specific communication scenario.

[0033] Further use cases with more stringent requirements are envisioned for NR URLLC, such as factory automation, transportation, and power distribution. The stringent requirements include high reliability (10 6 reliability up to a certain level), high availability, packet sizes up to 256 bytes, time synchronization up to a few microseconds (depending on the use case, the value can be 1 microsecond or a few microseconds depending on the frequency range and low latency in the 0.5ms-1ms range (especially for targeted user plane latency of 0.5ms).

[0034] Furthermore, for NR URLLC, several technical extensions may be available from the perspective of the physical layer. These technical extensions include the extension of the Physical Downlink Control Channel (PDCCH) related to compact DCI, the repeated transmission of PDCCH, and the increase in PDCCH monitoring. Also, the extension of UCI (Uplink Control Information) is related to the extension of enhanced HARQ (Hybrid Automatic Repeat Request) and CSI feedback. In addition, there may be extensions of PUSCH related to mini-slot level hopping, and extensions of retransmission / repeated transmission. The term "mini-slot" refers to a Transmission Time Interval (TTI) that contains fewer symbols than a slot (a slot has 14 symbols).

[0035] <QoS Control> The QoS (Quality of Service) model of 5G is based on QoS flows and supports both QoS flows that require a guaranteed flow bit rate (GBR (Granteed Bit Rate) QoS flows) and QoS flows that do not require a guaranteed flow bit rate (non-GBR QoS flows). Therefore, at the NAS level, a QoS flow is the finest granularity QoS classification in a PDU session. A QoS flow is identified within a PDU session by a QoS Flow ID (QFI) that is carried in an encapsulation header via the NG-U interface.

[0036] For each UE, the 5GC establishes one or more PDU sessions. For each UE, the NG-RAN establishes at least one Data Radio Bearer (DRB) for each PDU session, e.g., as shown above with reference to Figure 3. Additional DRBs for the QoS flows of that PDU session can be configured later (when this is up to the NG-RAN). The NG-RAN maps packets belonging to different PDU sessions to different DRBs. NAS-level packet filters in the UE and the 5GC associate UL packets and DL packets with QoS flows, while AS-level mapping rules in the UE and the NG-RAN associate UL QoS flows and DL QoS flows with DRBs.

[0037] Figure 5 shows the non-roaming reference architecture for 5G NR (see Section 4.23 of Non-Patent Document 5). An Application Function (AF) (e.g., an external application server hosting 5G services as illustrated in Figure 4) interacts with the 3GPP core network to provide services, for example, to support application influence on traffic routing, access to a Network Exposure Function (NEF), or interact with a policy framework for policy control (e.g., QoS control) (see Policy Control Function (PCF)). Based on the operator's deployment, Application Functions that are considered trusted by the operator can interact directly with the relevant Network Functions. Application Functions that are not permitted by the operator to directly access Network Functions interact with the relevant Network Functions using an external exposure framework via the NEF.

[0038] Figure 5 further illustrates further functional units of the 5G architecture, namely, Network Slice Selection Function (NSSF), Network Repository Function (NRF), Unified Data Management (UDM), Authentication Server Function (AUSF), Access and Mobility Management Function (AMF), Session Management Function (SMF), and Data Network (DN, e.g., operator-provided services, Internet access, or third-party services). All or part of the core network functions and application services may be deployed and run in a cloud computing environment.

[0039] Therefore, the present disclosure provides an application server (e.g., an AF in a 5G architecture) comprising: a transmitter that, in operation, transmits a request including QoS requirements for at least one of a URLLC service, an eMBB service, and an mMTC service to at least one of 5GC functions (e.g., an NEF, an AMF, an SMF, a PCF, an UPF, etc.) to establish a PDU session including a radio bearer between a gNodeB and a UE according to the QoS requirements; and a control circuit that, in operation, performs a service using the established PDU session.

[0040] <NTN: Non-Terrestrial Network> Satellites will continue to be the most effective means of reaching areas beyond terrestrial coverage, as well as reaching passengers on trains, aircraft, and ships. Therefore, including satellites as an integral part of the 5G ecosystem adds resilience. The satellite industry is participating in various committees, including 3GPP, EC, and ITU-T, to ensure that satellite systems are integrated as an essential part of the 5G ecosystem. The objectives are: 1) to support highly available and reliable connectivity using satellites for use cases such as ubiquitous coverage, disaster relief, public safety requirements, emergency response, remote sensor connectivity, and broadcast services; 2) to support an air interface with one-way latency of 275 ms or less when satellite connectivity is involved; and 3) to support seamless mobility between terrestrial networks and satellite-based networks with variable latency.

[0041] 3GPP has considered and described NR-based operation in non-terrestrial networks (NTN) (see, for example, Non-Patent Document 6, "Studies on New Radio (NR) for supporting non-terrestrial networks" (Version 15.4.0) and Non-Patent Document 7, "Solutions for supporting non-terrestrial networks in NR" (Version 16.0.0)). A non-terrestrial network (NTN) refers to, for example, a network or a segment of a network that uses RF resources onboard an airborne or space-based entity for transmission. Examples of airborne or space-based entities include: · Spacecraft: Satellites (including Low Earth Orbiting (LEO), Medium Earth Orbiting (MEO), Geostationary Earth Orbiting (GEO), and Highly Elliptical Orbiting (HEO) satellites). Aircraft: High Altitude Platforms (HAPs) encompass Unmanned Aircraft Systems (UAS), including Lighter than Air Unmanned Aircraft Systems (LTAs) and Heavier than Air UASs (HTAs), which typically operate in a quasi-stationary manner at altitudes between 8 and 50 km.

[0042] For example, a UAS or satellite platform is connected to a 5G network through one or several gateways linked to a data network. The NTN may include system elements such as an NTN-enabled terminal (which may refer to a 3GPP UE or a terminal specific to the satellite system if the satellite does not directly serve 3GPP UEs), a service link referring to a radio link between the user equipment and the space platform / air platform, an air platform carrying a payload, a gateway connecting the space / air platform to the core network, and a feeder link referring to a radio link between the space platform / air platform and a gateway center. The platform may implement either transparent or regenerative payload transmission with the following exemplary characteristics: In a transparent payload, the payload remains unchanged and the platform acts as a repeater by filtering, converting, and amplifying the radio signal. In a regenerative payload, the platform has some or all of the base station functionality. The platform may perform demodulation / modulation, switching / routing, encoding / decoding, in addition to radio frequency filtering, conversion, and amplification. Inter-Satellite Links (ISLs) can optionally be used to form constellations of satellites. ISLs are transport links between satellites.

[0043] Figure 6 shows an exemplary NG RAN architecture based on transparent satellites. According to an exemplary implementation (see Section 5.1 of Non-Patent Document 7), the satellite payload implements frequency conversion and radio frequency amplifiers in both the uplink and downlink directions. This corresponds to an analog RF relay station. Therefore, the satellite repeats the NR-Uu radio interface from the feeder link (between the NTN gateway and the satellite) to the service link (between the satellite and the UE) and vice versa. The satellite radio interface (SRI) on the feeder link is NR-Uu. In other words, the satellite does not terminate the NR-Uu.

[0044] Figure 7 shows an exemplary NG RAN architecture based on a regenerative satellite. According to an exemplary implementation (see section 5.2 of Non-Patent Document 8), the NG-RAN logical architecture as described in Non-Patent Document 9 is used as a reference for the NTN scenario. The satellite payload implements regeneration of signals received from Earth. The NR-Uu radio interface is on the service link between the UE and the satellite. The satellite radio interface (SRI) is the feeder link between the NTN gateway and the satellite. The satellite radio interface (SRI) is the transport link between the NTN GW and the satellite.

[0045] Figure 8 shows an example scenario in which three UEs (UE1, UE2, UE3) are served from satellite S1, which communicates via feeder links with gNBs and NTN gateways, and via inter-satellite links (ISLs) with another nearby satellite S2.

[0046] There are different types of satellites that provide communications: low Earth orbit (LEO) satellites or geosynchronous equatorial orbit (GEO) satellites (also called geostationary satellites). Geostationary satellites appear fixed because they move at the same angular velocity as the Earth and orbit along a path parallel to the Earth's rotation, thereby providing coverage to a specific area. From the ground, GEO satellites appear to be stationary. LEO satellites orbit at altitudes between 160 and 2,000 kilometers (99 and 1,200 miles). A constellation of LEO satellites can provide continuous, global coverage as the satellites move. Unlike GEO satellites, LEO satellites also travel at much faster speeds due to their closer proximity to the Earth.

[0047] GEO satellites have many uses, including weather forecasting, satellite radio, and television. However, because GEO satellites orbit at such high altitudes, there is a long communication lag (latency) as signals travel to and from these satellites. For this reason, many important communications are handled through LEO satellite networks, which allow for high-speed connections without wires or cables.

[0048] The functionality of relays and repeaters is already known in 3GPP, for example, from LTE-Advanced. These are also known as L1 and L2 relays, respectively, and can be used for coverage extension within a cell. L1 relays perform amplify-and-forward and impose very short delays, typically only 1 μs. Advanced relays, also known as smart relays, are a type of relay that features time / frequency-selective repetition. This allows them to repeat only signals intended for the served user equipment (UE), thereby reducing interference within the cell and power consumption of the relay. L2 relays perform decode / redecode operations that impose larger delays, typically several milliseconds. However, despite the functional similarity of relays in LTE-Advanced and NTN, they have fundamentally different designs due, for example, to different backhaul links and the associated round-trip times (RTTs).

[0049] <Further improvements> One of the major challenges for integrating NTN into 5G is its long RTT, which ranges from 25 to 540 ms depending on the satellite orbit. A large RTT can severely impact user scheduling performance, especially in transparent payload scenarios (see above). This is due to the fact that the channel conditions for the UE can vary significantly between the time instance when the UE is scheduled by the gNB and the time instance when data is exchanged between the UE and the satellite (uplink or downlink). For example, if the channel conditions deteriorate significantly after the UE is scheduled for downlink / uplink transmission, there is a high probability that the data transmission will fail.

[0050] NTN platforms, including UAS and satellites, are also limited in total transmit power due to limited onboard power sources. Therefore, efficient power allocation is a key concern for NTNs.

[0051] The inventors have identified the potential drawbacks and challenges discussed above and have therefore identified the possibility of providing improved transmission procedures involving satellites that make it possible to avoid or mitigate one or more of the problems identified above. The present invention relates to different solutions and variants for such improved transmission procedures.

[0052] <Embodiment> In the following, UEs, base stations, and procedures for meeting these needs are described for new radio access technologies envisioned for 5G mobile communication systems, but may also be used in LTE mobile communication systems. Various implementations and variations are also described. The following disclosure is facilitated by, and may be based, for example, at least in part on, the above discussion and discoveries.

[0053] In general, it should be noted that many assumptions have been made herein so as to be able to explain the principles underlying the present disclosure in a clear, concise, and understandable manner. However, it should be understood that these assumptions are merely examples made herein for illustrative purposes and are not intended to limit the scope of the present disclosure. Those skilled in the art will understand that the principles described in the following disclosure and claims can be applied to different scenarios and in ways not explicitly described herein.

[0054] Furthermore, although specific terminology used in the context of new radio access technologies for upcoming 3GPP 5G communication systems has not yet been fully determined or may ultimately change, some of the terms used below, such as procedures, entities, and layers, are closely related to the terms used in LTE / LTE-A systems or in current 3GPP 5G standardization. Therefore, the terms may change in the future without affecting the functionality of the embodiments. Therefore, those skilled in the art will recognize that the embodiments and their scope of protection are not limited to the specific terms illustratively used herein due to the absence of newer or ultimately agreed-upon terms, but should be understood more broadly in terms of the functions and concepts underlying the functions and principles of the present disclosure.

[0055] For example, a "mobile station" or "mobile node" or "user terminal" or "user equipment (UE)" is a physical entity (physical node) in a communication network. A node may have several functional entities. A functional entity refers to a software or hardware module that performs and / or provides a predetermined set of functions to another functional entity of the same node or another node or network. A node may have one or more interfaces that attach it to a communication device or medium through which it can communicate. Similarly, a network entity may have logical interfaces that attach a functional entity to a communication device or medium through which it can communicate with another functional entity or a correspondent node.

[0056] The term "base station" or "radio base station" herein refers to a physical entity in a communication network. A base station, like a mobile station, may have several functional entities. A functional entity refers to a software or hardware module that performs and / or provides a predetermined set of functions for another functional entity of the same node or another node or network. A physical entity performs several control tasks related to communication devices, including one or more of scheduling and configuration. It should be noted that base station functionality and communication device functionality may be integrated into one device. For example, a mobile terminal may also implement base station functionality for other terminals. In LTE, the terminology used is eNB (or eNodeB), while in 5G NR, the terminology currently used is gNB.

[0057] The term non-terrestrial network (NTN) entity, as introduced in the above section related to NTNs, can be broadly understood as an entity of a non-terrestrial network, such as a spacecraft or an aircraft. In the following, a satellite will be considered only as an example of such an NTN entity, although it will be clear that other examples of NTN entities are also covered.

[0058] In the following solution, it is exemplarily assumed that the improved transmission procedure is performed as part of data transmission between a UE and a base station (e.g., a gNB) via a satellite. The scenario of FIG. 8 already introduced above can be exemplarily assumed below. For simplicity of explanation, it is exemplarily assumed that the gateway and the gNB are co-located, thereby avoiding a formal separation of the gateway and the gNB (base station) in the following description. Therefore, in the following, the improved transmission procedure is described as occurring between the UE, the NTN entity, and the gNB, without specifically mentioning that the gateway is located between the NTN entity and the gNB.

[0059] FIG. 9 shows a general, simplified, exemplary block diagram of a user equipment (also referred to as a communication device) and a scheduling device (here assumed to be located, by way of example, in a base station, e.g., an eLTE eNB (alternatively referred to as an ng-eNB) or a gNB in ​​5G NR). The UE and the eNB / gNB communicate with each other via a (radio) physical channel using a transceiver unit, respectively. Furthermore, the NTN entity may have the same or similar structure as the scheduling device, e.g., including a transceiver unit and processing circuitry.

[0060] Any of the devices may include a transceiver and a processing circuit. The transceiver may further include a receiver and a transmitter, and / or may function as both a receiver and a transmitter. The processing circuit may be one or more hardware components, such as one or more processing units or any LSI. There is an input / output point (or node) between the transceiver and the processing circuit, and the processing circuit, in operation, controls the transceiver, i.e., controls the receiver and / or transmitter, and exchanges receive / transmit data. The transceiver may include an RF front end, including one or more antennas, amplifiers, RF modulators / demodulators, etc., as the transmitter and receiver. The processing circuit may control the transceiver to perform control tasks, such as transmitting user data and control data provided by the processing circuit and / or receiving user data and control data that are further processed by the processing circuit. The processing circuit may also be responsible for performing other processes, such as judgment, decision, calculation, measurement, etc. The transmitter may be responsible for performing the transmission process and other processes related thereto. The receiver may be responsible for performing the process of reception and other processes related thereto, such as monitoring the channel.

[0061] Various implementations of the improved transmission procedure are described below. In this regard, improved entities, such as an improved UE, an improved NTN entity, and an improved base station, that participate in the improved transmission procedure are presented. Corresponding methods of behavior of the UE, the NTN entity, and the BS are also provided.

[0062] Figure 10 shows a simplified exemplary structure of an NTN entity (such as a satellite) according to one exemplary solution for an improved transmission procedure that may be implemented based on the general device structure described in connection with Figure 9. The various structural elements of the NTN entity shown in this figure may be interconnected, for example, using corresponding input / output nodes (not shown), for example, to exchange control and user data and other signals. Although not shown for purposes of illustration, the NTN entity may include additional structural elements.

[0063] As can be seen from FIG. 10, the NTN entity may include a channel state report receiving unit, a channel state report transmitting unit, a scheduling information receiving unit, an updated channel state determining circuit, an adaptive transmit power association determining circuit, and a transmit power adaptation circuit.

[0064] Thus, in the present case as will become apparent from the disclosure below, the receiver of the NTN entity may be exemplarily configured to at least partially perform one or more of receiving a channel condition report, receiving an updated channel condition report, receiving scheduling information, receiving data, receiving configuration information, etc.

[0065] Furthermore, as will become apparent from the disclosure below, the processing circuitry (also referred to as a processing unit) of the NTN entity may therefore be exemplarily configured to at least partially perform one or more of: determining updated channel conditions; determining whether and by how much to adapt transmit power for uplink or downlink transmissions; determining whether to cancel scheduled downlink / uplink transmissions; determining a priority associated with downlink data; selecting appropriate uplink scheduling information from among multiple uplink scheduling information; adapting (a portion thereof) the uplink scheduling information; performing estimations regarding whether a scheduled transmission is likely to succeed or fail;

[0066] Furthermore, in the present case as will become clear from the disclosure below, the transmitter unit of the NTN entity may therefore be exemplarily configured to at least partially perform one or more of the following: forwarding a received channel condition report to the base station; transmitting data to the UE using a specific transmission power; forwarding uplink scheduling information to the UE; transmitting an updated channel condition report to the base station; transmitting a negative acknowledgement to the base station; etc.

[0067] One exemplary solution, disclosed in further detail below, is implemented by an NTN entity including: a receiver unit of the NTN entity receives, from a user equipment (UE), a channel condition report providing information about a channel between the UE and the NTN entity; a transmitter unit of the NTN entity forwards the received channel condition report to a base station; the receiver unit receives, from the base station, scheduling information regarding downlink or uplink transmission of data at the UE; a processor unit of the NTN entity determines updated channel conditions; the processor determines, based on the updated channel conditions, whether to adapt a transmit power for a downlink or uplink transmission according to the received scheduling information; and, if the processor determines to adapt the transmit power, adapts the transmit power for the downlink or uplink transmission.

[0068] A corresponding sequence diagram of exemplary UE behavior consistent with the above UE is defined below and shown in Figure 11. The method is performed by a user equipment: receiving a channel condition report from a user equipment (UE) providing information about a channel between the UE and an NTN entity; forwarding the received channel condition report to a base station; receiving scheduling information for downlink or uplink transmission of data at the UE from a base station; determining updated channel conditions; determining whether to adapt a transmit power for a downlink or uplink transmission in response to the received scheduling information based on the updated channel conditions; if it is determined to adapt the transmit power, adapting the transmit power for downlink transmission or uplink transmission; Includes.

[0069] According to this improved transmission procedure, it is possible to control the transmit power of an uplink or downlink transmission based on previously determined updated channel conditions. By directly obtaining and using the updated channel conditions at the NTN entity, excessive round trip delays are avoided, and the actual channel conditions of the channel between the NTN entity and the UE can be taken into account for the uplink and downlink transmissions. For example, the transmit power can be adapted (e.g., increased) to compensate for a deterioration in channel quality compared to the channel quality indicated by the channel condition report and used by the base station when scheduling the downlink or uplink transmission. On the other hand, in situations where the channel quality improves compared to the channel quality indicated to the base station by the channel condition report, the transmit power can be reduced to avoid using excessive transmit power.

[0070] The adaptive transmit power solution described above therefore overcomes the drawbacks mentioned above for scenarios where channel conditions vary significantly between the instance where the UE is scheduled by the base station and the instance where data is exchanged (uplink or downlink) between the UE and the NTN entity (e.g., satellite).

[0071] As is already clear from the above, the improved transmission procedure also provides an improved UE. Figure 12 shows a simplified exemplary UE structure according to one exemplary solution of the improved transmission procedure, which may be implemented based on the general UE structure described in relation to Figure 9. The various structural elements of the UE shown in Figure 12 may be interconnected, for example, using corresponding input / output nodes (not shown), for example, to exchange control data and user data and other signals. Although not shown for illustrative purposes, the UE may include further structural elements.

[0072] As can be seen from FIG. 12, the UE may include a channel state report transmitter, an uplink scheduling information receiver, an updated channel state determination circuit, an adaptive transmit power association determination circuit, a transmit power adaptation circuit, and an uplink transmitter.

[0073] In the present case, as will become apparent from the disclosure below, the receiver of the UE may therefore be exemplarily configured to at least partially perform one or more of: receiving uplink scheduling information for uplink transmissions; receiving uplink resource information from the NTN entity indicating uplink resources usable by the UE for transmitting an updated channel condition report; receiving downlink data transmissions; receiving NACK notifications; etc.

[0074] In this case, as will become apparent from the disclosure below, the processing circuitry of the UE may therefore be exemplarily configured to at least partially perform one or more of: determining updated channel conditions; determining whether and how to adapt transmit power for uplink transmissions; determining whether to cancel scheduled uplink transmissions; determining whether to send a negative acknowledgement for a downlink data transmission; etc.

[0075] In the present case, as will become apparent from the disclosure below, the transmitter of the UE may therefore be exemplarily configured to at least partially perform one or more of: sending a channel condition report to an NTN entity; performing uplink transmission of uplink data using adapted transmit power; sending updated channel condition reports to other NTN entities; etc.

[0076] One exemplary solution, which will be disclosed in further detail below, is implemented by a UE, including: a transmitter unit of the UE sends a channel condition report to a non-terrestrial network (NTN) entity, the channel condition report providing information about a channel between the UE and the NTN entity; a processor unit of the UE determines updated channel conditions of the channel between the UE and the NTN entity; a receiver unit of the UE receives, from the NTN entity, uplink scheduling information for uplink transmission of uplink data from the UE to the NTN entity; the processor determines, based on the updated channel conditions, whether to adapt transmit power for the uplink transmission of the uplink data; and, if the processor determines to adapt the transmit power, adapts the transmit power. The transmitter unit performs uplink transmission of the uplink data to the NTN entity according to the received uplink scheduling information and based on the adapted transmit power.

[0077] A corresponding sequence diagram of exemplary UE behavior along the above-mentioned lines is shown in Figure 13. A corresponding method is performed by the UE: sending a channel condition report to a non-terrestrial network (NTN) entity, the report providing information about the channel between the UE and the NTN entity; determining an updated channel condition of the channel between the UE and the NTN entity; receiving, from the NTN entity, uplink scheduling information for uplink transmission of uplink data from the UE to the NTN entity; determining whether to adapt a transmit power for uplink transmission of uplink data based on the updated channel conditions; adapting the transmission power if it is determined that the transmission power should be adapted; performing uplink transmission of uplink data to the NTN entity according to the received uplink scheduling information and based on the adapted transmission power; Includes.

[0078] Thus, the improved UE participates in an improved transmission procedure to overcome the drawbacks identified above for scenarios in which channel conditions change significantly between the instance in which the UE is scheduled by the base station and the instance in which data is transmitted from the UE to the NTN entity (e.g., a satellite). In this case, the UE takes current channel conditions into account when performing uplink transmissions, rather than relying solely on the transmit power indicated by uplink scheduling information generated by the base station based on previous channel condition reports that may indicate significantly different channel conditions than the current ones. Thus, inaccurate scheduling information that may be caused by large round-trip delays involved in such scenarios can be compensated for by the transmit power adaptation defined by the above solution.

[0079] For example, the transmit power may be adapted (e.g., increased) by the UE to compensate for a deterioration in channel quality as indicated by the channel condition report compared to the channel quality against which the base station scheduled the uplink transmission, whereas in situations where the channel quality improves compared to the channel quality indicated by the channel condition report, the transmit power may be reduced to avoid using excessive transmit power.

[0080] As is already clear from the above, the improved transmission procedure also provides an improved base station. Figure 14 shows a simplified exemplary base station structure according to one exemplary solution of the improved transmission procedure, which may be implemented based on the general base station structure described in connection with Figure 9. The various structural elements of the base station shown in Figure 14 may be interconnected, for example, using corresponding input / output nodes (not shown), for example, to exchange control data and user data and other signals. Although not shown for illustrative purposes, the base station may include further structural elements.

[0081] As can be seen from FIG. 14, the base station may include a channel condition report receiving unit, an uplink scheduling information preparing circuit, and an uplink scheduling information transmitting unit.

[0082] In this case, as will become apparent from the disclosure below, the receiver of the base station may therefore be exemplarily configured to at least partially perform one or more of receiving a channel condition report, receiving a negative acknowledgement to a previously scheduled downlink transmission, etc.

[0083] In this case, as will become apparent from the disclosure below, the processing circuitry of the base station may therefore be exemplarily configured to at least partially perform one or more of: preparing a plurality of different uplink scheduling information; determining a pool of radio resources; determining whether to perform a retransmission of downlink data; etc.

[0084] In the present case, as will become clear from the disclosure below, the transmitter of the base station may therefore be exemplarily configured to at least partially perform one or more of the following: transmitting a plurality of different uplink scheduling information to the NTN entity; transmitting information regarding the determined pool of radio resources; transmitting a configuration message to the NTN entity or other NTN entities; transmitting downlink scheduling information and downlink data; etc.

[0085] One exemplary solution disclosed in more detail below is implemented by a base station including: a receiving unit of the base station receives, from a non-terrestrial network (NTN) entity, a channel condition report providing information about a channel between a user equipment (UE) and the NTN entity; a processing unit of the base station prepares, based on the received channel condition report, a plurality of different uplink scheduling information for transmission of uplink data by the UE, the different uplink scheduling information differing from each other in at least transmit power values; and a transmitting unit of the base station transmits the prepared plurality of different uplink scheduling information to the NTN entity.

[0086] A corresponding sequence diagram of exemplary base station behavior along the lines described above is shown in Figure 15. A corresponding method is performed by the base station: receiving a channel condition report from a non-terrestrial network (NTN) entity, the channel condition report providing information about a channel between a user equipment (UE) and the NTN entity; preparing, based on the received channel state report, a plurality of different uplink scheduling information for uplink data transmission by the UE, the different uplink scheduling information differing from each other in at least transmit power values; transmitting the prepared plurality of different uplink scheduling information to an NTN entity; Includes.

[0087] Therefore, the improved base station participates in an improved transmission procedure to overcome the drawbacks identified above for scenarios in which channel conditions vary significantly between the instance in which the UE is scheduled by the base station and the instance in which data is transmitted from the UE to an NTN entity (e.g., a satellite). In this case, the base station prepares multiple different uplink scheduling information to be used for scheduled uplink transmissions, which differ from each other primarily in the value of the transmit power. Thus, by providing the opportunity to select from several uplink scheduling information for essentially similarly scheduled uplink transmissions, the base station facilitates the NTN entity to select uplink scheduling information with an appropriate transmit power according to the current channel conditions determined at the satellite.

[0088] There are several different implementations of the NTN entities, UEs and base stations mentioned above and ways in which the three devices work together in an improved transmission procedure.

[0089] In the following, various exemplary implementations of the improved transmission procedures are described, each providing information on how different entities interact with each other to achieve the benefits associated with the improved transmission procedures.

[0090] For the sake of presentation, the improved transmission procedures are described separately for downlink and uplink transmissions. Nevertheless, although the uplink and downlink are described separately below, the procedures and behaviors of participating devices that are specifically related to the uplink or downlink can also be combined such that the improved transmission procedures not only cover uplink and downlink transmissions separately, but are also applicable to both uplink and downlink transmissions.

[0091] However, other variations of the improved transmission procedure are applicable to both the downlink and the uplink and will also be described separately.

[0092] <Improved Downlink Transmission Procedure> In the following, various variants of the improved transmission procedure are described for a downlink scenario, whereby downlink transmission of downlink data is scheduled by the gNB to be forwarded by the satellite to the UE.

[0093] A general and simplified example of message exchange between a UE, a satellite, and a gNB in ​​an improved transmission procedure in the downlink is shown in Figure 16. The satellite may be, for example, a satellite as described in relation to Figures 10 and 11.

[0094] As can be seen from the figure, it is assumed that the UE is already connected to the satellite and the gNB. According to a first illustrated step, the UE transmits a channel condition report to the satellite, which is then forwarded to the gNB. The channel condition report can be understood to provide information about the channel between the UE and the satellite (e.g., information obtained by the UE from measurements performed on the channel).

[0095] This channel information can be used by the gNB to schedule subsequent downlink transmissions by determining appropriate scheduling parameters such as one or more of the following: transmit power, modulation order, coding rate, time-frequency radio resources, etc. The gNB transmits the downlink scheduling information and downlink data to the satellite.

[0096] According to the improved downlink transmission procedure, before performing an actual downlink transmission scheduled by the gNB, the satellite determines the current channel conditions. The current channel conditions may differ from the channel conditions reflected in a channel condition report previously forwarded to the gNB. For example, the satellite may determine updated channel conditions itself (e.g., by performing measurements on the satellite itself) or may determine updated channel conditions itself based on a further updated channel condition report received from the UE. Further details regarding possible variations regarding the determination of updated channel conditions in the presently described improved downlink transmission procedure are provided below.

[0097] The satellite can determine whether to adapt the transmit power in the downlink transmission so that possible differences between the updated channel conditions and the previous channel conditions communicated to the gNB are taken into account. Furthermore, assuming that the satellite determines to adapt the transmit power of the downlink transmission, the satellite also needs to determine by how much to adapt the transmit power.

[0098] This decision by the satellite on whether and how to adapt its transmit power takes into account updated channel conditions, which is particularly useful in scenarios with large round-trip delays where the current channel conditions are likely to differ significantly from the channel conditions on which the gNB based its scheduling decision.

[0099] Furthermore, this decision by the satellite of whether and how to adapt the transmit power may take into account additional parameters. For example, the satellite may take into account minimum transmission-related parameters that need to be met for a scheduled transmission. One example of such a minimum transmission-related parameter is a minimum Signal-to-Interference plus Noise Ratio (SINR). Further details regarding possible variations on determining whether and how to adapt the transmit power in the presently described improved downlink transmission procedure are provided below.

[0100] Therefore, the satellite can determine whether to adapt the transmit power of the scheduled downlink transmission, taking into account the updated channel conditions in particular. For example, in a scenario where the channel conditions have significantly deteriorated, the scheduling parameters in the downlink scheduling information for the downlink data may no longer be appropriate. To compensate for this channel deterioration, the satellite may increase the transmit power, thereby increasing the likelihood that the downlink transmission can be received at the UE. On the other hand, in a scenario where the channel conditions have significantly improved, the satellite may not adapt the transmit power or may reduce the transmit power.

[0101] Additionally or alternatively, the satellite may take into account the minimum transmission-related parameters when determining the above. For example, the satellite may determine whether a downlink transmission scheduled by a gNB satisfies the minimum transmission-related parameters, and if not, adapt (e.g., increase) the transmit power to meet the requirements of the minimum transmission-related parameters. In other cases, transmit power adaptation may not be required or it may not be possible to adapt the transmit power to meet the minimum transmission-related parameters.

[0102] In the exemplary scenario of FIG. 16, it is assumed that the satellite determines to adapt its transmit power and therefore transmits downlink data using the adapted transmit power and based on the scheduled transmission parameters of the received downlink scheduling information.

[0103] Various variations of the improved downlink transmission procedure presented in relation to Figure 16 are described below in relation to Figure 17. Figure 17 is a general and simplified example of a message exchange between a UE, a satellite, and a gNB in ​​an improved transmission procedure in the downlink, which combines various variations described below.

[0104] According to one exemplary variant, the satellite can perform an estimation as to whether a scheduled downlink transmission of downlink data is likely to be successful. This estimation can be based on previously determined updated channel conditions. For example, the satellite may learn that the channel conditions have substantially deteriorated (in which case the scheduled downlink transmission will likely fail) compared to an instance in which a channel condition report was forwarded to the gNB for scheduling the downlink data. Optionally, the satellite may also consider how much the channel deterioration can be compensated for by increasing the transmission power as described above, and whether minimum transmission-related parameter requirements, including the increase in transmission power, are met.

[0105] If the satellite estimates that the scheduled downlink transmission will not be successful, it can send a negative acknowledgement of the scheduled downlink transmission to the gNB already at this early point in time when the downlink transmission is not being performed. The negative acknowledgement can therefore be exemplarily referred to as an early NACK.

[0106] As a further optional implementation of this variant, the satellite can decide whether to cancel a scheduled downlink transmission of downlink data to the UE depending on the previous estimation, for example, the satellite estimation can provide information that the downlink transmission is very unlikely to be successful, in which case the satellite can simply decide to cancel the scheduled downlink transmission so that the scheduled downlink transmission is not performed and an early NACK transmission is performed.

[0107] On the other hand, the satellite's estimation may result in a low probability of success for the scheduled downlink transmission, but still merit in attempting the scheduled downlink transmission. In this case, the satellite may proceed with the scheduled downlink transmission (possibly with adapted transmit power). The satellite may decide to send an early NACK to the gNB to expedite a possible downlink data retransmission. On the other hand, the satellite may decide not to send an early NACK, but rather to wait for transmission feedback from the UE regarding the performed downlink transmission.

[0108] A further exemplary improvement relates to the case where the satellite transmits an early NACK while still attempting to perform the downlink transmission. According to this exemplary improvement, the UE may be notified of the early NACK for the downlink transmission transmitted by the satellite to the gNB. Thus, the UE receives the downlink transmission and the NACK notification and derives therefrom that the satellite has already transmitted to the gNB a NACK for the just-received downlink transmission. Thus, even if the UE does not successfully decode the received downlink transmission, the UE does not transmit a further NACK to the satellite, because it knows that the gNB has already provided an early NACK that would trigger a retransmission of the failed downlink transmission.

[0109] On the other hand, according to one example, if the UE successfully decodes the received downlink transmission, an ACK may be sent to the satellite to avoid further downlink transmissions, even if the satellite receives rescheduled downlink scheduling information and the same downlink data.

[0110] In connection with determining whether a scheduled downlink transmission will be successful, and in connection with determining whether a scheduled downlink transmission will be canceled, one or more appropriate thresholds for the likelihood of a successful downlink transmission may be set in the satellite.

[0111] According to a particular exemplary implementation of this variation, the estimation of whether a scheduled downlink transmission will be successful can also take into account whether the UE is in or out of coverage of the satellite. For example, if the satellite learns that the UE has moved out of coverage, the satellite may cancel the scheduled downlink transmission and instead transfer the downlink data to another satellite that is the target of a handover that the UE has performed or is currently performing.

[0112] An exemplary implementation of this variation is shown in Figure 17. As can be seen, the satellite, after determining the updated channel conditions (here illustratively based on a previously received updated channel condition report), also determines whether to cancel the scheduled downlink transmission. In this particular example, it is assumed that the satellite actually determines to cancel the downlink transmission and provides an early NACK to the gNB. According to a further optional implementation, the satellite also provides an updated channel condition report to the gNB in ​​order to provide the gNB with updated channel state information to improve rescheduling of downlink data transmissions.

[0113] Depending on the implementation, the early NACK sent by the satellite indicates that a downlink transmission previously scheduled by the gNB was canceled and not actually performed by the satellite. Thus, because the UE did not receive anything from the originally scheduled downlink transmission attempt, the gNB knows based on the early NACK that it should perform rescheduling as if it were the first transmission of downlink data rather than a retransmission. For example, the gNB may transmit the same redundancy version of the downlink data as in the original case, rather than a different redundancy version of the downlink data.

[0114] As a further example, downlink scheduling information for downlink data may also be generated to indicate that the transmitted downlink data is new downlink data, as if it were an initial transmission of downlink data and not a retransmission. In one example implementation, the new data indicator in the scheduling information may be toggled to achieve this.

[0115] The gNB reschedules the downlink transmission of the same DL data and determines different scheduling parameters based on the updated channel conditions. The gNB then transmits the downlink scheduling information and the downlink data to the satellite.

[0116] The satellite may then perform steps similar to those performed for the first downlink transmission attempt, including determining updated channel conditions, determining whether to cancel the downlink transmission, and determining whether and how to adapt the downlink transmit power. In the example scenario of Figure 17, it is assumed that in the second attempt, the satellite determines to perform the downlink transmission with the adapted transmit power.

[0117] As mentioned above, the satellite may decide to perform the scheduled downlink transmission even if it is unlikely to be successful and may send an early NACK to the gNB (not shown in FIG. 17). In that case, in contrast to the example described above in connection with FIG. 17, the early NACK does not trigger an initial transmission of the same downlink data as before, but rather a regular retransmission of the downlink data (e.g., another redundant version of the downlink data to achieve a combining gain at the UE). Thus, the gNB may schedule a downlink retransmission of the downlink data, for example, based on an updated channel condition report received from the satellite, and provide the corresponding downlink scheduling information and downlink data to the satellite for further forwarding to the UE.

[0118] In either case, by using early NACK feedback from the satellite, the gNB can reschedule the downlink data taking into account the updated channel conditions and retransmit the downlink data to the satellite to achieve a more robust transmission (e.g., transmission using a lower coding rate and / or a lower modulation order and / or a higher level of aggregation or repetition R).

[0119] Overall, the cancellation of scheduled downlink transmissions can save transmit power, which could theoretically be allocated to transmitting downlink data to other UEs. Furthermore, the transmission of an early NACK from the satellite to the gNB triggers data (re)transmissions sooner.

[0120] FIG. 18 conceptually illustrates the results of transmit power adaptation according to the improved downlink transmission procedure described above. Specifically, FIG. 18 illustrates different amounts of transmit power exemplary allocated among three UEs, UE1, UE2, and UE3, at different timing instances. At time instance t1, FIG. 18 illustrates the transmit power allocated by the satellite for each of the downlink transmissions according to how the downlink transmissions are scheduled. Meanwhile, at time t2, the transmit power at UE1 is increased to compensate for deteriorating channel conditions, while the transmit powers scheduled for downlink transmissions to UE2 and UE3 are maintained. Furthermore, it is assumed that at time t3, the downlink data transmission to UE1 is canceled by the satellite (e.g., due to a significant degradation in channel quality), thereby allowing the unused transmit power scheduled for UE1 (or only a portion thereof) to be reallocated for downlink data transmissions to UE2 and UE3.

[0121] According to a further exemplary variation, which may be combined with the other described variations but need not be combined, the satellite takes into account the priority of the downlink data, e.g., whether and how much to adapt the transmit power in the downlink transmission. For example, the satellite may determine a higher transmit power for the downlink transmission of high priority data compared to the downlink transmission of low or normal priority data. As a result, high priority data can be transmitted by the satellite to the UE and higher transmission robustness is achieved.

[0122] According to one example, information regarding the priority of the downlink data can be provided by the gNB to the satellite, for example, included with the DL data or transmitted with the DL data and included with downlink scheduling information regarding the DL data (see Figure 17).

[0123] Further alternatively, the satellite can use such priority information to know the priority of DL data without it being explicitly provided by the gNB.

[0124] According to a further exemplary variation, which may be combined with other described variations, but need not be combined, the satellite takes into account negative acknowledgements (NACKs) and / or positive acknowledgements (ACKs) (e.g., of a HARQ function) transmitted for previous downlink transmissions to determine whether and how to adapt the downlink transmit power. More specifically, NACKs / ACKs may be monitored by the satellite as an indication of the channel conditions of the channel between the satellite and the UE. For example, when the number of NACKs received for previously transmitted downlink transmissions is greater than a previously set NACK threshold, this is considered to be an indication that the channel conditions are poor, which may lead to a further increase in the transmit power used in the downlink.

[0125] According to a further option, negative and / or positive acknowledgements (NACK / ACK) transmitted in association with uplink transmissions are also monitored by the satellite and taken into account in determining whether and how to adapt the downlink transmit power.

[0126] Additionally, the time at which an ACK / NACK for an uplink or downlink transmission is received is taken into consideration, eg, giving more weight to recent ACK / NACKs than older ACK / NACKs.

[0127] <Improved uplink transmission procedure> Various variants of the improved transmission procedure are described below for an uplink scenario: According to variants, uplink transmission of uplink data is scheduled by the gNB to be performed by the UE towards the satellite.

[0128] The basic principle is that the transmit power for uplink transmissions is adapted based on the latest updated channel conditions, rather than depending only on the transmit power indicated by the corresponding uplink scheduling information generated by the gNB. The adaptation of the uplink transmit power can be done on the satellite side (see the first variant below) or on the UE side (see the second variant below). Both cases are described separately below.

[0129] According to a first variant, the uplink transmit power adaptation is mainly performed by the satellite. Figure 19 shows an example of a general and simplified message exchange between the UE, the satellite and the gNB according to this first variant.

[0130] According to the assumptions made in the downlink transmission procedure described above, it is assumed that the UE is already connected to the satellite and the gNB. According to the first illustrated step, the UE transmits a channel condition report to the satellite, which is then forwarded to the gNB. The channel condition report can be understood to provide information about the channel between the UE and the satellite (e.g., information obtained by the UE from measurements performed on the channel).

[0131] This channel information may be used by the gNB to schedule subsequent uplink transmissions by determining appropriate scheduling parameters such as, for example, one or more of transmit power, modulation order, coding rate, time-frequency radio resources, etc. The gNB also transmits uplink scheduling information to the satellite.

[0132] The improved uplink transmission procedure is in many aspects quite similar to the improved downlink transmission procedure described above, e.g., with respect to determining updated channel conditions and determining whether and how to adapt the transmit power, with the main difference being that in a downlink scenario, the satellite can directly adapt the transmit power it uses to perform downlink transmissions, whereas in an uplink scenario, the satellite needs to provide appropriate instructions for the UE to perform uplink transmissions based on the adapted uplink transmit power.

[0133] In line with the above, prior to scheduling an uplink transmission for a UE, the satellite determines current channel conditions. The current channel conditions may differ from the channel conditions reflected in a channel condition report previously forwarded to the gNB. For example, the satellite may determine updated channel conditions itself (e.g., by performing measurements on the satellite itself) or may determine updated channel conditions itself based on a further updated channel condition report received from the UE.

[0134] The satellite can determine whether to adapt the transmit power in the uplink transmission so that possible differences between the updated channel conditions and the previous channel conditions communicated to the gNB are taken into account. Furthermore, assuming the satellite determines to adapt the transmit power of the uplink transmission, the satellite also needs to determine how much to adapt the transmit power. This decision by the satellite of whether and how to adapt the transmit power takes into account the updated channel conditions.

[0135] Similar to the improved downlink transmission procedure (see section above), this decision by the satellite of whether and how to adapt its transmit power may take into account further parameters, such as minimum transmission-related parameters.

[0136] This allows the satellite to determine whether a transmit power adaptation for uplink transmissions is actually necessary, and if so, what appropriate transmit power value should be instructed to the UE.

[0137] In the exemplary scenario of Figure 19, it is assumed that the satellite determines to adapt the transmit power in the uplink transmission and therefore transmits corresponding uplink scheduling information to the UE indicating such adapted transmit power.

[0138] The UE then performs uplink transmission in accordance with the received uplink scheduling information (and therefore using adapted transmit power as dictated by the uplink scheduling information provided by the satellite).

[0139] In the above solution of the first variant described in relation to Figure 19, it was generally assumed that the satellite provides the UE with corresponding uplink scheduling information indicating the adapted transmit power. In the following, two different exemplary implementations are presented on how the satellite can achieve this.

[0140] According to a first implementation of this first variant, several different uplink scheduling information differing in at least the indicated transmission power are provided by the gNB, which may for example be a gNB as described in relation to Figures 14 and 15. Figure 20 shows an example of a general and simplified message exchange between the UE, the satellite, and the gNB according to this first implementation of the first variant.

[0141] As can be seen from the figure, it is assumed that first a channel condition report is generated by the UE and transmitted to a satellite, which then forwards this channel condition report to a gNB, for example, for scheduling purposes, and the gNB prepares uplink scheduling information for transmission of uplink data by the UE based on the received channel condition report.

[0142] For example, the gNB schedules uplink transmissions at an "optimal" transmit power value according to the channel conditions indicated in the channel condition report. However, the gNB may generate various uplink scheduling information, each including a different transmit power value (e.g., a Transmission Power Command (TPC) corresponding to a different transmit power value), assuming various channel conditions (e.g., degraded or improved channel conditions).

[0143] The generated uplink scheduling information may further differ from each other not only with respect to the indicated transmission power, but also by other parameters such as modulation order or coding rate.

[0144] As can be seen from FIG. 20 , the gNB transmits the generated multiple uplink scheduling information to the satellite. Then, the satellite determines, based on updated channel conditions (e.g., channel conditions updated based on the satellite's own measurements), which transmit power value among the transmit power values ​​encoded in the different uplink scheduling information is the most appropriate one for the UE to perform uplink transmission at that time. Then, the satellite selects the uplink scheduling information having the most appropriate transmit power value from the various uplink scheduling information. The selection by the satellite can be based on the current channel conditions. Thus, the satellite can adapt the transmit power based on the updated channel conditions by selecting the appropriate uplink scheduling information previously prepared by the gNB.

[0145] The thus selected uplink scheduling information is then transmitted to the UE, so that the UE performs scheduled uplink transmissions according to the received uplink scheduling information, including using the transmit power of the uplink transmissions according to the transmit power value selected by the satellite.

[0146] According to a second implementation of the first variant, instead of selecting appropriate uplink scheduling information from multiple available uplink scheduling information, the satellite adapts the uplink transmission power by directly modifying the corresponding transmit power parameter (e.g., the transmit power control field corresponding to the transmit power parameter) in a single provided uplink scheduling information to be forwarded to the UE. Unlike what has been described above in connection with FIG. 20, the gNB does not generate multiple different uplink scheduling information, but instead prepares a single uplink scheduling information and forwards it to the satellite. This single uplink scheduling information indicates a specific transmit power value to be used in the context of the scheduled uplink transmission (e.g., a transmit power value determined based on the channel conditions indicated by a previously received channel condition report).

[0147] As described above, the satellite determines, based on the updated channel conditions, an appropriate transmit power value to be used for uplink transmission and included in the uplink scheduling information. The satellite then generates corresponding uplink scheduling information based on the determined appropriate uplink transmit power value and based on the previously received uplink scheduling information. For example, the satellite may modify only the transmit power-related values ​​of the received uplink scheduling information to reflect the transmit power value determined based on the updated channel conditions. The satellite then transmits the adapted uplink scheduling information to the UE.

[0148] Thus, the UE performs uplink transmissions scheduled by the received uplink scheduling information, including using a transmit power for the uplink transmission according to the transmit power value adapted by the satellite.

[0149] Different variants of the improved uplink transmission procedure of this first variant are described below in conjunction with Figures 19 and 20. According to one exemplary adaptation (not shown in any of the figures), early success estimation and possible cancellation of uplink transmissions can be performed in a manner corresponding to the downlink transmission described in conjunction with Figure 17. For this purpose, the satellite can perform estimation as to whether a scheduled uplink transmission of uplink data by a UE is likely to be successful. Thus, the satellite can determine the current channel conditions as described above (e.g., see Figure 17) and, based on this, can determine that the channel conditions have substantially deteriorated compared to the instance when the channel condition report was forwarded to the gNB for uplink data scheduling. Thus, the satellite can conclude that the scheduled uplink transmission will fail with a high probability. Furthermore, optionally, the satellite may also take into account how much channel degradation can be compensated for by increasing the transmission power as described above, optionally taking into account minimum transmission-related parameters.

[0150] If the satellite estimates that the scheduled uplink transmission will not be successful, it may transmit a negative acknowledgement of the scheduled uplink transmission to the gNB even at this early time point when no uplink transmission is being performed. The negative acknowledgement may therefore exemplarily be referred to as an early NACK.

[0151] As a further optional implementation, the satellite can determine whether to cancel a scheduled uplink transmission of uplink data depending on previous estimations. For example, the satellite estimation can provide information that the uplink transmission is highly unlikely to be successful, in which case the satellite can simply decide to cancel the scheduled uplink transmission by not transmitting uplink scheduling information to the UE. In that case, the satellite can send a NACK to the gNB to trigger rescheduling of the uplink transmission (possibly together with information about updated channel conditions to improve rescheduling).

[0152] The gNB reschedules the uplink transmission in response to the received early NACK and takes into account the latest updated channel state information, if available. From the early NACK, the gNB learns that the uplink transmission was canceled and was never even performed by the UE. Therefore, since the UE did not transmit anything, the gNB knows based on the early NACK that it should perform rescheduling as if it were a first transmission of uplink data, not a retransmission.

[0153] The uplink scheduling information for the uplink data is also generated such that the uplink scheduling information indicates that the scheduling is for new uplink data as if the uplink data were an initial transmission rather than a retransmission.

[0154] The gNB reschedules the uplink transmission and determines different scheduling parameters based on the updated channel conditions. The gNB then transmits the uplink scheduling information to the satellite. The satellite can then perform, for example, the same operations as were performed in the initial uplink transmission attempt.

[0155] On the other hand, the satellite's estimation may result in a low probability of success for the scheduled uplink transmission, but still merit in attempting the scheduled uplink transmission. In this case, the satellite transmits uplink scheduling information to the UE (possibly with adapted transmit power). The satellite may decide to send an early NACK to the gNB to accelerate possible rescheduling in the uplink. On the other hand, the satellite may decide not to send an early NACK and wait for the uplink transmission from the UE to be forwarded to the gNB.

[0156] As previously discussed in connection with estimating success and canceling downlink transmissions, the UE may use appropriate thresholds for the likelihood of a successful uplink transmission and for determining whether to cancel a scheduled uplink transmission (e.g., taking into account whether the UE is in or out of satellite coverage).

[0157] In either case, by using early NACK feedback from the satellite, the gNB can reschedule uplink data taking into account updated channel conditions (e.g., using a lower coding rate and / or a lower modulation order and / or a higher level of aggregation or repetition R) to achieve a more robust transmission. Furthermore, cancellation of scheduled uplink transmissions can save transmit power. Furthermore, transmission of an early NACK from the satellite to the gNB triggers data (re)transmissions sooner.

[0158] According to a second variant, the uplink transmission power adaptation is performed on the UE side (rather than by the satellite). Figure 21 shows an example of a general and simplified message exchange between the UE, the satellite and the gNB according to this second variant. The UE relevant to this second variant may be, for example, the UE described in relation to Figures 12 and 13.

[0159] Similar exemplary assumptions can be made as those made for the solution described above with reference to Figure 19. For example, the initial steps, including those related to the transmission of a channel condition report by the UE and how the gNB receives the channel condition report, generates appropriate uplink scheduling information, and transmits the uplink scheduling information to the satellite, can be similar or identical.

[0160] However, unlike the above solution, in this second variant the satellite does not adapt its transmission power, it simply forwards the received uplink scheduling information to the UE.

[0161] However, on the UE side, when the UE receives the UL scheduling information and prepares uplink transmission of uplink data, it also determines updated channel conditions of the channel between the UE and the satellite. As already exemplarily assumed above, the channel conditions may be determined by the UE based on measurements of reference signals received from the satellite, such as RS or DMRS (Demodulation Reference Signal) in the downlink. The updated channel conditions may be different, e.g., better or worse, than the channel conditions reflected in the channel condition report previously forwarded to the gNB.

[0162] Based on the updated channel conditions (e.g., taking into account possible differences between the updated channel conditions communicated to the gNB in ​​the channel condition report and the previous channel conditions), the UE determines whether and how to adapt the transmit power for uplink transmissions. If the UE determines to adapt the uplink transmit power to compensate for differences in channel conditions, the UE also needs to determine how much to adapt the transmit power. This decision by the UE of whether and how to adapt the transmit power takes the updated channel conditions into account.

[0163] Similar to the improved downlink transmission procedure (see section above), this decision by the UE of whether and how to adapt its transmit power may also take into account further parameters, such as a minimum transmission-related parameter (e.g., minimum SINR). For example, the UE may attempt to adapt its transmit power to meet this minimum SINR. For example, if the minimum SINR cannot be met, the UE may decide to cancel uplink transmission, even when using the maximum possible transmit power (see below).

[0164] As a result, the UE can determine whether a transmit power adaptation for uplink transmissions is actually necessary, and if so, which appropriate uplink transmit power value should be used.

[0165] The UE then performs uplink transmission using the adapted transmit power, and the uplink data is then further forwarded by the satellite towards the gNB.

[0166] Various adaptations of the improved uplink transmission procedure presented for the second variant are described below in connection with FIG.

[0167] According to one exemplary adaptation (shown in FIG. 22), the early success estimation and possible cancellation of the uplink transmission may be performed in a manner corresponding to the downlink transmission described in relation to FIG. 17 and the solution described for the solution in which the satellite performs the early success estimation and possible cancellation of the uplink transmission.

[0168] As can be seen from Figure 22, the UE may further determine whether to perform the uplink transmission with the adapted transmit power or to cancel the uplink transmission due to a very low probability of success, which may include the UE performing an estimation of whether the scheduled uplink transmission of uplink data by the UE is likely to be successful, e.g., based on previously determined updated channel conditions.

[0169] 22, if the UE determines that the uplink transmission will not be successful, the UE may also decide to cancel the scheduled uplink transmission, e.g., if the probability of success is very low. Thus, the UE may not perform the uplink transmission and instead send, e.g., an early NACK indicating that the UE's transmission was skipped but that the uplink scheduling information was successfully received.

[0170] The satellite determines that the UE does not perform an uplink transmission even though the uplink transmission is scheduled, and therefore determines that the UE has canceled the uplink transmission. In one example, the satellite can request the gNB to reschedule the uplink transmission for the UE.

[0171] Alternatively, the UE may estimate that the scheduled uplink transmission is unlikely to be successful, but that it is still worthwhile to attempt the scheduled uplink transmission, in which case the UE will still perform the uplink transmission to the satellite.

[0172] In both the first and second variants described above (i.e., in the adaptation of the uplink transmission power by the satellite and the UE), the optional adaptation provides that the priority of the uplink data can also be taken into account when determining whether and how to adapt the uplink transmission power. The UE is fully aware of the priority of the uplink data it wishes to transmit. Furthermore, in the first variant in which the satellite performs the determination, the satellite can be aware of the priority of the uplink data, for example, based on a scheduling request or a buffer status report sent by the UE. The scheduling request or the buffer status report indicates the presence or amount of data available for transmission in the UE's uplink buffer and information about the priority of the uplink data.

[0173] For example, a higher transmit power may be determined for uplink transmission of high priority data, while a relatively lower transmit power may be used for uplink transmission of low or normal priority data, thereby allowing the high priority data to be transmitted by the UE with greater transmission robustness.

[0174] <General variations applicable to both improved downlink and uplink transmission procedures> In the following, various modifications are presented with respect to the specific aspects already introduced above for improved transmission procedures for uplink / downlink. In other words, the following modifications may be applicable to both the improved downlink transmission procedure (e.g., see the above description related to Figures 16-18) and the improved uplink transmission procedure (e.g., see the above description related to Figures 19-22).

[0175] A first variant is applicable to the solutions described herein, in which the UE transmits updated channel condition reports to the satellite, which simply assumed that the UE would provide updated channel condition reports to the satellite, but did not specify details on how the UE could achieve this.

[0176] Conceptually, the updated channel condition report may, but need not, differ from the normal channel condition report that the UE sends to the satellite. The normal channel condition report may, for example, be configured to be sent periodically, i.e., every x milliseconds. Additionally or alternatively, the normal channel condition report may be aperiodic, for example, triggered by an event occurring at the UE (e.g., a measurement event) or explicitly requested by the satellite or gNB. As described below, the updated channel condition report may differ from the normal channel condition report based on one or more of the following: Different triggers (e.g., different periods, different events (e.g., measurement events), different instructions) Different time / frequency resources (e.g. different PRBs) Different transmission parameters (modulation method, coding rate, etc.) Different content

[0177] According to one exemplary solution of this variant, the UE may be configured to transmit an updated channel condition report differently from how and when it transmits a normal channel condition report. This involves the UE determining whether and when to transmit an updated channel condition report to the satellite indicating updated channel conditions. For example, the gNB or the satellite may configure the UE to transmit updated channel condition reports to the satellite with higher periodicity to keep the satellite up-to-date on the channel conditions. Another example is based on one or more conditions that must be met for the UE to transmit an updated channel condition report; for example, an updated channel condition report is transmitted when the UE measures a certain degradation in channel quality (e.g., a degradation compared to the channel conditions reported in a previous normal channel condition report). According to another example, such a condition is the UE leaving the satellite's coverage area. Such a solution is particularly advantageous for the satellite to learn about degraded channel conditions while keeping the additional overhead caused by updated channel condition reports low.

[0178] According to one exemplary solution of this variant, the gNB can allocate dedicated radio resources for the UE to transmit these updated channel condition reports, and the satellite informs the UE about these dedicated radio resources. The UE can then use these dedicated radio resources to transmit the updated channel condition reports to the satellite. The dedicated radio resources can, for example, indicate specific time and / or frequency radio resources to be used by the UE.

[0179] According to another example, the gNB defines a pool of radio resources (e.g., time and / or frequency resources) and transmits this resource pool information to the satellite. The satellite can then determine which radio resources from the pool should be assigned to the UE for transmitting an updated channel condition report. These selected uplink radio resources are then notified to the UE.

[0180] As a result, the UE may use different radio resources for transmitting the updated channel condition report than for transmitting the normal channel condition report.

[0181] According to another exemplary solution, the UE may use transmission parameters for transmitting the updated channel condition report that are different from the transmission parameters used for transmitting the normal channel condition report. For example, the specific transmission parameters for the updated channel condition report may be such that a more robust transmission is ensured, e.g., a lower order modulation scheme or a lower coding rate. Also, the transmission parameters may be selected to facilitate the decoding process at the satellite side.

[0182] According to yet another exemplary solution, the updated channel condition report may have different content from the normal channel condition report, for example, the updated channel condition report may include one or more of the SINR, CSI, CQI, SRS, location, movement direction, and velocity of the UE.

[0183] An exemplary implementation of the updated channel condition report significantly simplifies the content and transmission of the updated channel condition report. For example, the updated channel condition report merely serves to provide an indication of whether the channel conditions have deteriorated compared to the channel conditions indicated by a previously transmitted normal channel condition report. Such a simple indication may be transmitted by the UE, for example, so that a satellite receiver can detect the presence of such an updated channel condition report transmission based solely on energy detection. The transmission by the UE may, for example, not use modulation or coding. Thus, the satellite monitors pre-agreed radio resources for such spikes in transmit power, and if it detects some transmit energy on those radio resources, it determines that an updated channel condition report should be transmitted by the UE and derives therefrom that the channel conditions have significantly deteriorated.

[0184] According to another variant, which can be used in combination with the other described variants, but need not be used, the updated channel condition report may not be further forwarded to the gNB, unlike the way the satellite normally handles channel condition reports. As explained in some of the above solutions, the contents of the updated channel condition report are used exclusively on the satellite side, in which case the updated channel condition report does not need to be forwarded to the gNB. On the other hand, in the above other solutions, it is advantageous to have information about updated channel conditions (e.g., when rescheduling downlink or uplink transmissions), and therefore it is advantageous for the satellite to forward the updated channel condition report to the gNB or at least provide the gNB with appropriate information in other ways. Such behavior of the satellite may be configured, for example, by the gNB.

[0185] Another variation, which can be used in combination with the other described variations, but need not be, relates to the solution described herein, in which a satellite determines updated channel conditions, for example, in the context of determining whether to adapt its uplink / downlink transmit power. As already alluded to above (see, for example, FIG. 17), for example, the satellite can be provided by the UE with an updated channel condition report indicating the updated channel conditions. Additionally or alternatively, the satellite may perform its own measurements or determinations to derive the current channel conditions. In one option, the satellite may also take into account information about the UE's location.

[0186] According to yet another variant, which can be used in combination with the other described variants but need not be used, dedicated radio resources can be allocated for the transmission of downlink reference signals that the UE can use to determine updated channel conditions. For example, the UE may use downlink reference signals (such as DMRS) to determine current channel conditions. According to this variant, corresponding downlink reference signals used by the UE for this determination can be transmitted in the downlink on specific radio resources (known to the UE). These dedicated radio resources can be determined by the gNB, for example, and assigned to the satellite. According to another exemplary option, the gNB can define a pool of radio resources and inform the satellite about the resource pool. The satellite can then select radio resources from the resource pool and use them to transmit downlink reference signals to be used by the UE to determine updated channel conditions. The UE can, for example, be informed of the selected radio resources so that it can use them for channel condition determination.

[0187] Another variation, which may be used in combination with the other described variations, but need not be, addresses the case where the UE's serving satellite is unable to decode the updated state report itself. Therefore, such a satellite may not be able to determine the updated channel conditions needed to perform the improved transmission procedure. The capabilities of different satellites, including their ability to decode normal or updated channel state reports, can vary greatly. This improved variation provides a solution to such a scenario by using the capabilities of nearby satellites to decode the updated channel state report and provide the appropriate information to the serving satellite.

[0188] Broadly speaking, the variations rely on nearby satellites with appropriate capabilities receiving and decoding the updated channel condition report and providing the serving satellite with appropriate information regarding the updated channel conditions.

[0189] Various implementations are possible for how a nearby satellite receives an updated channel condition report. According to one exemplary implementation, the nearby satellite can monitor the transmission of an updated channel condition report transmitted by the UE to the UE's serving satellite. To facilitate monitoring by the nearby satellite, the nearby satellite may be provided with information (e.g., from the serving satellite or from the gNB) regarding the radio resources used by the UE to transmit the updated channel condition report to the serving satellite. Thus, the nearby satellite only needs to monitor the indicated radio resources for the updated channel condition report.

[0190] According to another exemplary implementation, a UE may be simultaneously connected to two satellites (a primary (serving) satellite and a neighboring satellite with higher capabilities) (similar to dual connectivity). According to this exemplary implementation, the UE transmits an updated channel condition report to the secondary (neighboring) satellite, where the updated channel condition report provides information about the channel condition between the UE and the primary (serving) satellite. In this case, the secondary (neighboring) satellite also decodes the updated channel condition report and provides the decoded information to the primary (serving) satellite.

[0191] According to yet another example implementation, the serving satellite can provide an updated channel condition report to a neighboring satellite, which then decodes the updated channel condition report and returns the decoded information to the serving satellite, as shown in Figure 23.

[0192] In either case, the above solution allows simple satellites serving a UE (e.g., simple satellites in that the serving satellite is unable to decode the updated channel condition reports and is unable to determine the updated channel conditions itself) to also participate in the improved transmission procedure.

[0193] The gNB may be responsible for discovering and configuring neighboring satellites to decode updated channel condition reports on behalf of the serving satellite. The configuration thus instructs neighboring satellites (with appropriate capabilities) to receive, decode, and forward updated channel condition reports from the UE to the corresponding serving satellite. The configuration by the gNB may also indicate, for example, the specific radio resources to be used by the UE for transmitting the updated channel condition reports, so that neighboring satellites can monitor the corresponding radio resources.

[0194] This solution, in which the neighboring satellite decodes the updated channel condition report instead of the serving satellite, is particularly useful when the round-trip time between the two satellites (the neighboring satellite and the serving satellite) is smaller than the round-trip time between the serving satellite and the gNB (the gNB can also provide the serving satellite with updated channel conditions), but is also useful in other cases. According to one exemplary option, the serving satellite may determine whether to transmit the updated channel condition report to the neighboring satellite or the gNB depending on the round-trip times between the serving satellite and the gNB and between the serving satellite and the neighboring satellite, respectively. For example, the serving satellite may determine to transmit the updated channel condition report to the nearest entity, which is the neighboring satellite or the gNB.

[0195] Further Aspects According to a first aspect, there is provided a non-terrestrial network (NTN) entity including: a receiver unit of the NTN entity receives, from a user equipment (UE), a channel condition report providing information about a channel between the UE and the NTN entity; a transmitter unit of the NTN entity forwards the received channel condition report to a base station; the receiver unit receives from the base station scheduling information related to downlink or uplink transmission of data at the UE; a processor unit of the NTN entity determines updated channel conditions; the processor determines, based on the updated channel conditions, whether to adapt a transmit power for the downlink or uplink transmission according to the received scheduling information; and, if the processor determines to adapt the transmit power, adapts the transmit power for the downlink or uplink transmission.

[0196] According to a second aspect provided in addition to the first aspect, the scheduling information is for the downlink transmission, and the receiver receives downlink data from the base station in association with the downlink scheduling information. The adapting of the transmit power by the processor includes adapting the transmit power of the downlink transmission of the received downlink data. The transmitter performs the downlink transmission of the downlink data to the UE in accordance with the downlink scheduling information and based on the adapted transmit power.

[0197] According to a third aspect provided in addition to the second aspect, the processing unit performs an estimation as to whether the scheduled downlink transmission of the downlink data to the UE will be successful based on the updated channel conditions. If the determined estimation is an estimation that the scheduled downlink transmission will not be successful, the transmitting unit transmits a negative acknowledgement for the scheduled downlink transmission to the base station. In an optional implementation form, the transmitting unit performs the scheduled downlink transmission of the downlink data to the UE.

[0198] According to a fourth aspect provided in addition to the third aspect, the processing unit determines whether to cancel the scheduled downlink transmission of the downlink data to the UE based on the determined estimation. If it is determined to cancel the scheduled downlink transmission, the scheduled downlink transmission is not performed and the transmission of the negative acknowledgement by the transmitting unit is performed. If it is determined not to cancel the scheduled downlink transmission, the scheduled downlink transmission of the downlink data to the UE is performed. In an optional implementation form, the processing unit determines to cancel the scheduled downlink transmission of the downlink data to the UE when the UE is out of coverage of the NTN entity, and the transmitting unit forwards the downlink data to another NTN entity that is a target of handover of the UE from the NTN entity to the other NTN entity.

[0199] According to a fifth aspect provided in addition to one of the second to fourth aspects, the processing unit determines a priority associated with the downlink data to be transferred to the UE. The decision to adapt a transmit power of the scheduled downlink or uplink transmission takes into account the priority associated with the downlink data. In an optional implementation, information regarding the priority associated with the downlink data is included with the downlink scheduling information for the downlink transmission of the data or the downlink data.

[0200] According to a sixth aspect provided in addition to the first aspect, the scheduling information is for uplink transmission, and the adapting of the transmit power by the processing unit includes adapting the transmit power for the uplink transmission of uplink data.

[0201] According to a seventh aspect provided in addition to the sixth aspect, the received scheduling information for uplink transmission includes a plurality of different uplink scheduling information, and the different uplink scheduling information differ from each other at least in transmit power values. The adapting of the transmit power by the processing unit includes selecting uplink scheduling information having a most appropriate transmit power based on the updated channel condition. The transmitting unit transmits the selected uplink scheduling information to the UE.

[0202] According to an eighth aspect provided in addition to the sixth aspect, the received scheduling information for the uplink transmission indicates a value of a transmit power for the scheduled uplink transmission, and the adapting of the transmit power by the processing unit includes adapting the value of the transmit power indicated by the uplink scheduling information to a different value based on the updated channel conditions, and the transmitting unit transmits the uplink scheduling information having the different value of the transmit power to the UE.

[0203] According to a ninth aspect provided in addition to one of the sixth to eighth aspects, the processing unit performs an estimation as to whether the scheduled uplink transmission of the uplink data by the UE will be successful based on the updated channel conditions. If the determined estimation is an estimation that the scheduled uplink transmission will not be successful, the transmitting unit, in operation, transmits a negative acknowledgement for the scheduled uplink transmission to the base station. In an optional implementation, the transmitting unit transmits the uplink scheduling information to the UE.

[0204] According to a tenth aspect provided in addition to the ninth aspect, the processing unit determines whether to cancel the scheduled uplink transmission of the uplink data by the UE based on the determined estimation. If it is determined to cancel the scheduled uplink transmission, the uplink scheduling information is not transmitted to the UE. If it is determined not to cancel the scheduled uplink transmission, the uplink scheduling information is transmitted to the UE. According to an eleventh aspect provided in addition to one of the first to tenth aspects, the receiver monitors negative acknowledgements received from the UE for previous downlink transmissions from the NTN entity to the UE. The adaptation of the transmit power by the processor takes into account the monitored negative acknowledgements and, optionally, negative acknowledgements for previous uplink transmissions from the UE to the NTN entity. In an optional implementation, if an amount of monitored negative acknowledgements is greater than a NACK threshold, the adaptation of the transmit power increases the transmit power.

[0205] According to a twelfth aspect provided in addition to one of the first to eleventh aspects, adapting the transmit power includes increasing or decreasing the transmit power. In an optional implementation, the transmit power is increased if the updated channel conditions indicate a worse channel condition than a previous channel condition provided to the base station. In an optional implementation, the decision to adapt the transmit power for the scheduled downlink or uplink transmission is further based on minimum transmission-related parameters to be met for the scheduled transmission.

[0206] According to a thirteenth aspect provided in addition to one of the first to twelfth aspects, the receiver receives an updated channel state report from the UE, and the determination of the updated channel state by the processor is performed based on the received updated channel state report. Additionally or alternatively, the processor estimates the updated channel state from one or more of measurements performed on the channel, feedback on the scheduled downlink transmission, and information about a location of the UE.

[0207] According to a fourteenth aspect provided in addition to the thirteenth aspect, the receiver receives the decoded updated channel condition report from another NTN entity that has the capability to decode the updated channel condition report and has a transmission link to the NTN entity. In an optional implementation form, if the NTN entity cannot decode the updated channel condition report, the transmitter forwards the updated channel condition report to the other NTN entity. In an optional implementation form, the transmitter does not forward the updated channel condition report to the base station.

[0208] According to a 15th aspect, in addition to the 13th or 14th aspect, the processing unit determines dedicated uplink radio resources to be allocated to the UE for transmission of the updated channel condition report to the NTN entity. The transmission unit provides uplink resource information regarding the determined dedicated uplink radio resources to the UE. In an optional implementation form, the processing unit determines the dedicated uplink radio resources such that the dedicated uplink radio resources are determined from a pool of uplink radio resources allocated by the base station. In an optional implementation form, the processing unit determines dedicated downlink radio resources to be used by the NTN entity for transmitting to the UE a reference signal used in determining the updated channel condition. In an optional implementation form, the processing unit determines the dedicated downlink radio resources such that the dedicated downlink radio resources are determined from a pool of downlink radio resources allocated by the base station.

[0209] According to a 16th aspect provided in addition to one of the 13th to 15th aspects, the content of the updated channel condition report is different from the content of the channel condition report. In an optional implementation form, the updated channel condition report provides notification of whether channel conditions have deteriorated compared to the channel conditions indicated by the previously received channel condition report. In an optional implementation form, the receiver performs energy detection to detect the presence of the updated channel condition report, and the presence of the updated channel condition report indicates deterioration of the channel conditions compared to the channel conditions indicated by the previously received channel condition report, or a specific situation at the UE, such as the UE being out of coverage of the NTN entity. In an optional implementation form, the updated channel condition report indicates at least one of a current location of the UE, a current moving direction of the UE, and a velocity of the UE.

[0210] According to a seventeenth aspect, a method is provided, performed by a non-terrestrial network (NTN) entity, receiving a channel condition report from a User Equipment (UE) providing information about the channel between the UE and the NTN entity; forwarding the received channel condition report to a base station; receiving scheduling information for downlink or uplink transmission of data in the UE from the base station; determining an updated channel state; determining whether to adapt a transmit power for the downlink or uplink transmission in response to the received scheduling information based on the updated channel conditions; if it is determined to adapt the transmission power, adapting the transmission power for the downlink transmission or the uplink transmission. A method is provided.

[0211] According to an eighteenth aspect, there is provided a user equipment (UE) comprising: a transmitter unit of the UE transmits a channel condition report to a non-terrestrial network (NTN) entity, providing information about a channel between the UE and the NTN entity; a processor unit of the UE determines updated channel conditions of the channel between the UE and the NTN entity; a receiver unit of the UE receives uplink scheduling information for uplink transmission of uplink data from the UE to the NTN entity from the NTN entity; the processor determines whether to adapt a transmit power of the uplink transmission of the uplink data based on the updated channel conditions; and if the processor determines to adapt the transmit power, adapts the transmit power; and the transmitter unit performs the uplink transmission of the uplink data to the NTN entity in accordance with the received uplink scheduling information and based on the adapted transmit power.

[0212] According to a 19th aspect provided in addition to the 18th aspect, the processing unit determines whether to cancel the scheduled uplink transmission of the uplink data to the NTN entity based on the updated channel conditions. If it is determined to cancel the scheduled uplink transmission, the scheduled uplink transmission is not performed. If it is determined not to cancel the scheduled uplink transmission, the scheduled uplink transmission is performed.

[0213] According to a twentieth aspect, provided in addition to the eighteenth or nineteenth aspect, the decision to adapt the transmit power of the scheduled uplink transmission of the uplink data takes into account a priority of the uplink data. In an optional implementation, the decision to adapt the transmit power for the scheduled uplink transmission is further based on minimum transmission-related parameters to be met for the scheduled uplink transmission.

[0214] According to a 21st aspect provided in addition to one of the 18th to 20th aspects, the processing unit determines whether to transmit an updated channel condition report indicating the updated channel conditions to the NTN entity. If the processing unit determines to transmit the updated channel condition report, the transmitting unit transmits the updated channel condition report to the NTN entity. In an optional implementation, the processing unit's determination of whether to transmit the updated channel condition report includes at least one condition being satisfied. In an optional implementation, one of the at least one condition is that the channel conditions have deteriorated compared to the channel conditions indicated by a previously transmitted channel condition report.

[0215] According to a 22nd aspect provided in addition to the 21st aspect, the receiver receives uplink resource information from the NTN entity informing the NTN entity of uplink radio resources usable by the UE for transmitting the updated channel state report, and the transmitter uses the notified uplink radio resources for transmitting the updated channel state report.

[0216] According to a 23rd aspect provided in addition to the 21st or 22nd aspects, the transmitter, in operation, transmits the updated channel condition report to another NTN entity, the other NTN entity having the capability to decode the updated channel condition report and having a transmission link to the NTN entity. In an optional implementation form, the UE is connected to the NTN entity and the other NTN entity simultaneously.

[0217] According to a 24th aspect provided in addition to one of the 18th to 23rd aspects, the receiver receives a downlink data transmission from the NTN entity. The receiver receives a NACK notification from the NTN entity indicating that a negative acknowledgement for the downlink data transmission has already been transmitted to a base station. The processor determines not to transmit a negative acknowledgement for the received downlink data transmission even if decoding of the received downlink data transmission is not successful.

[0218] According to a 25th aspect provided in addition to one of the 21st to 24th aspects, the content of the updated channel condition report is different from the content of the channel condition report. In an optional implementation form, the updated channel condition report provides notification of whether a channel condition has deteriorated compared to a channel condition indicated by the previously transmitted channel condition report. In an optional implementation form, the transmitter performs the transmission of the updated channel condition report such that the receiver of the NTN entity can detect the presence of the transmission of the updated channel condition report based on energy detection, and transmitting the updated channel condition report indicates deterioration of the channel condition compared to the channel condition indicated by the previously received channel condition report. In an optional implementation form, the updated channel condition report indicates at least one of a current location of the UE, a current moving direction of the UE, and a velocity of the UE.

[0219] According to a twenty-sixth aspect, a method, performed by a user equipment (UE), sending a channel condition report to a Non-Terrestrial Network (NTN) entity providing information about the channel between the UE and the NTN entity; determining an updated channel condition of the channel between the UE and the NTN entity; receiving uplink scheduling information for uplink transmission of uplink data from the UE to the NTN entity from the NTN entity; determining whether to adapt a transmit power of the uplink transmission of the uplink data based on the updated channel conditions; adapting the transmission power if it is determined to adapt the transmission power; performing the uplink transmission of the uplink data to the NTN entity in accordance with the received uplink scheduling information and based on the adapted transmission power; A method is provided which includes:

[0220] According to a 27th aspect, there is provided a base station comprising: a receiving unit of the base station receiving a channel condition report from a user equipment (UE) and a non-terrestrial network (NTN) entity, the channel condition report providing information about a channel between the NTN entity; a processing unit preparing, based on the received channel condition report, a plurality of different uplink scheduling information for transmission of uplink data by the UE, the different uplink scheduling information differing from each other in at least a transmit power value; and a transmitting unit transmitting the prepared plurality of different uplink scheduling information to the NTN entity.

[0221] According to a 28th aspect provided in addition to the 27th aspect, the processing unit determines a pool of radio resources usable by the UE for transmitting an updated channel condition report to the NTN entity. The transmitting unit transmits information about the determined pool of radio resources to the NTN entity. In an optional implementation, the transmitting unit, in operation, transmits a configuration message to the NTN entity for configuring the NTN entity not to forward the updated channel condition report to the base station.

[0222] According to a 29th aspect, which is provided in addition to the 27th or 28th aspects, the transmitter sends a configuration message to another NTN entity that has the capability to decode an updated channel condition report and has a transmission link to the NTN entity. The configuration message configures the other NTN entity to receive and decode the updated channel condition report from the UE and to forward the updated channel condition report to the NTN entity serving the UE. In an optional implementation, the configuration message indicates radio resources available for use by the UE to transmit the updated channel condition report.

[0223] According to a 30th aspect provided in addition to one of the 27th to 29th aspects, the receiver receives a negative acknowledgement from the NTN entity for a previously scheduled downlink transmission of downlink data to the UE, the negative acknowledgement further indicating that the NTN entity has canceled the previously scheduled downlink transmission of the downlink data to the UE. The processor determines, based on the negative acknowledgement, to perform a retransmission of the downlink data to the UE as if the retransmission were a first transmission of the downlink data and not a retransmission. The transmitter retransmits downlink scheduling information and the downlink data to the NTN entity to be forwarded to the UE. In an optional implementation, the downlink scheduling information for the downlink data indicates that the transmitted downlink data is new downlink data as if the transmitted downlink data were a first transmission of the downlink data and not a retransmission.

[0224] According to a 31st aspect provided in addition to one of the 27th to 29th aspects, the receiver receives a negative acknowledgement from the NTN entity for a previously scheduled downlink transmission of downlink data to the UE. The processor determines to perform a retransmission of the downlink data to the UE based on the negative acknowledgement. The transmitter retransmits the downlink scheduling information and the downlink data to the NTN entity to be forwarded to the UE, and optionally, the retransmission uses a different version of the downlink data for the retransmission.

[0225] According to a 32nd aspect provided in addition to the 30th or 31st aspects, the transmitter transmits information regarding the priority of the downlink data to the NTN entity. In an optional implementation form, the priority information is included together with the downlink data or together with the downlink scheduling information regarding the transmission of the downlink data. In an optional implementation form, the transmitter transmits minimum transmission-related parameters to the NTN entity. The minimum transmission-related parameters indicate minimum conditions to be satisfied by the scheduled transmission and are used in a process of determining whether to adapt the transmission power for the scheduled transmission.

[0226] According to a 33rd aspect provided in addition to one of the 27th to 32nd aspects, the different uplink scheduling information further has different modulation order values ​​or coding rate values ​​for the uplink data.

[0227] According to a thirty-fourth aspect, a method performed by a base station, receiving a channel condition report from a User Equipment (UE) and a Non-Terrestrial Network (NTN) entity providing information about the channel between said NTN entity; preparing, based on the received channel condition report, a plurality of different uplink scheduling information for uplink data transmission by the UE, the uplink scheduling information differing from each other in at least a transmit power value; transmitting the prepared plurality of different uplink scheduling information to the NTN entity; A method is provided which includes:

[0228] According to a thirty-fifth aspect, in operation, performed by a non-terrestrial network (NTN) entity: receiving a channel condition report from a user equipment (UE) providing information about a channel between the UE and the NTN entity; forwarding the received channel condition report to a base station; receiving scheduling information for downlink or uplink transmission of data in the UE from the base station; determining an updated channel state; determining whether to adapt a transmit power for the downlink or uplink transmission in response to the received scheduling information based on the updated channel conditions; if it is determined to adapt the transmission power, adapting the transmission power for the downlink transmission or the uplink transmission; An integrated circuit for controlling the operation of an NTN entity is provided, comprising:

[0229] According to a thirty-sixth aspect, in operation, performed by a user equipment (UE), sending a channel condition report to a Non-Terrestrial Network (NTN) entity providing information about the channel between the UE and the NTN entity; determining an updated channel condition of the channel between the UE and the NTN entity; receiving uplink scheduling information for uplink transmission of uplink data from the UE to the NTN entity from the NTN entity; determining whether to adapt a transmit power of the uplink transmission of the uplink data based on the updated channel conditions; adapting the transmission power if it is determined to adapt the transmission power; performing the uplink transmission of the uplink data to the NTN entity in accordance with the received uplink scheduling information and based on the adapted transmission power; An integrated circuit for controlling processing of a UE is provided, including:

[0230] According to a thirty-seventh aspect, in operation, performed by a base station: receiving a channel condition report from a User Equipment (UE) and a Non-Terrestrial Network (NTN) entity providing information about the channel between said NTN entity; preparing, based on the received channel condition report, a plurality of different uplink scheduling information for uplink data transmission by the UE, the uplink scheduling information differing from each other in at least a transmit power value; transmitting the prepared plurality of different uplink scheduling information to the NTN entity; An integrated circuit for controlling the processing of a base station is provided, comprising:

[0231] Hardware and Software Implementations of the Disclosure The present disclosure can be realized by software, hardware, or software in conjunction with hardware. Each functional block described in the above embodiments can be partially or entirely realized as an LSI, which is an integrated circuit. Each process described in the above embodiments can be partially or entirely controlled by a single LSI or a combination of LSIs. An LSI can be composed of individual chips, or a single chip can contain some or all of the functional blocks. An LSI may have data inputs and outputs. Depending on the level of integration, an LSI may be referred to as an IC (Integrated Circuit), a system LSI, a super LSI, or an ultra LSI. The integration method is not limited to LSIs; it can also be realized by dedicated circuits, general-purpose processors, or dedicated processors. Furthermore, a field programmable gate array (FPGA), which can be programmed after LSI fabrication, or a reconfigurable processor, which allows the connections and settings of circuit cells within an LSI to be reconfigured, can also be used. The present disclosure can be realized as digital or analog processing. Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derivative technologies, it is natural that such technology can be used to integrate functional blocks. The application of biotechnology, etc. is also a possibility.

[0232] The present disclosure may be implemented in any type of apparatus, device, or system having a communication function (collectively referred to as a communication apparatus).

[0233] The communications device may include a radio transceiver and processing / control circuitry. The radio transceiver may include a receiver and a transmitter, or both. The radio transceiver (transmitter, receiver) may include a radio frequency (RF) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or the like.

[0234] Non-limiting examples of communication devices include telephones (e.g., cell phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, notebooks), cameras (e.g., digital still / video cameras), digital players (e.g., digital audio / video players), wearable devices (e.g., wearable cameras, smartwatches, tracking devices), game consoles, digital book readers, telehealth / telemedicine devices, communication-enabled vehicles or mobile transportation (e.g., cars, airplanes, ships), and combinations of the above devices.

[0235] Communications equipment is not limited to portable or mobile equipment, but also includes non-portable or fixed equipment, devices, and systems of any kind, such as smart home devices (appliances, lighting equipment, smart meters or metering devices, control panels, etc.), vending machines, and any other "things" that may exist on an Internet of Things (IoT) network.

[0236] Communications include data communications via cellular systems, wireless LAN systems, communications satellite systems, etc., as well as data communications via combinations of these.

[0237] A communications device also includes devices such as controllers and sensors connected or coupled to a communications device that performs the communications functions described in this disclosure, such as controllers and sensors that generate control and data signals used by the communications device to perform the communications functions of the communications device.

[0238] The communication apparatus also includes infrastructure facilities, such as base stations, access points, and any other apparatus, device, or system that communicates with or controls the various apparatuses listed above, but are not limited to these.

[0239] (control signal) In the present disclosure, the downlink control signal (information) according to the present disclosure may be a signal (information) transmitted via a PDCCH of a physical layer, or may be a signal (information) transmitted via a MAC Control Element (CE) of a higher layer or an RRC. The downlink control signal may be a predefined signal (information).

[0240] The uplink control signal (information) according to the present disclosure may be a signal (information) transmitted via a PUCCH of a physical layer, or may be a signal (information) transmitted via a MAC CE of a higher layer or RRC. The uplink control signal may also be a predefined signal (information). The uplink control signal may be uplink control information (UCI), first-stage sidelink control information (SCI), or second-stage SCI.

[0241] (base station) In the present disclosure, a base station may be, for example, a Transmission Reception Point (TRP), a cluster head, an access point, a Remote Radio Head (RRH), an eNodeB (eNB), a gNodeB (gNB), a Base Station (BS), a Base Transceiver Station (BTS), a base unit, or a gateway. Furthermore, in sidelink communication, a terminal may be used instead of a base station. The base station may be a relay device that relays communication between an upper node and a terminal. The base station may be a roadside unit.

[0242] (Uplink / Downlink / Sidelink) The present disclosure may be applied to any of the uplink, downlink, and sidelink.

[0243] The present disclosure may be applied to, for example, uplink channels such as PUSCH, PUCCH, and PRACH, downlink channels such as PDSCH, PDCCH, and PBCH, and sidelink channels such as a physical sidelink shared channel (PSSCH), a physical sidelink control channel (PSCCH), and a physical sidelink broadcast channel (PSBCH).

[0244] The PDCCH, PDSCH, PUSCH, and PUCCH are examples of a downlink control channel, a downlink data channel, an uplink data channel, and an uplink control channel, respectively. The PSCCH and PSSCH are examples of a sidelink control channel and a sidelink data channel, respectively. The PBCH and PSBCH are examples of a broadcast channel, and the PRACH is an example of a random access channel.

[0245] (Data channel / Control channel) The present disclosure may be applied to both data channels and control channels. The channels in the present disclosure may be replaced with data channels including PDSCH, PUSCH, and PSSCH, and / or control channels including PDCCH, PUCCH, PBCH, PSCCH, and PSBCH.

[0246] (reference signal) In this disclosure, a reference signal is a signal known to both a base station and a mobile station, and each reference signal may be referred to as a reference signal (RS) or a pilot signal. A reference signal may be any of a DMRS, a Channel State Information - Reference Signal (CSI-RS), a Tracking Reference Signal (TRS), a Phase Tracking Reference Signal (PTRS), a Cell-specific Reference Signal (CRS), and a Sounding Reference Signal (SRS).

[0247] (time interval) In the present disclosure, the time resource unit is not limited to one or a combination of a slot and a symbol, and may be a time resource unit such as a frame, a superframe, a subframe, a slot, a subslot of a time slot, a minislot, or a symbol, an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single Carrier-Frequency Division Multiplexing Access (SC-FDMA) symbol, or other time resource unit. The number of symbols included in one slot is not limited to the number of symbols exemplified in the above-mentioned embodiment, and may be other numbers of symbols.

[0248] (frequency band) The present disclosure may be applied to both licensed and unlicensed bands.

[0249] (communication) The present disclosure may be applied to communication between a base station and a terminal (Uu link communication), communication between terminals (sidelink communication), and V2X (Vehicle to Everything) communication. The channels in the present disclosure may be rephrased as PSCCH, PSSCH, physical sidelink feedback channel (PSFCH), PSBCH, PDCCH, PUCCH, PDSCH, PUSCH, and PBCH.

[0250] The present disclosure can be applied to both terrestrial networks and non-terrestrial networks (NTNs) using satellites or high altitude pseudo satellites (HAPSs). The present disclosure can also be applied to networks with large cell sizes and terrestrial networks with large delays compared to the symbol length or slot length, such as ultra-wideband transmission networks.

[0251] (antenna port) An antenna port refers to a logical antenna (antenna group) formed from one or more physical antennas. That is, an antenna port does not necessarily refer to a single physical antenna, but may refer to an array antenna consisting of multiple antennas. For example, the number of physical antennas constituting an antenna port is not defined. Instead, an antenna port is defined as the smallest unit through which a terminal is permitted to transmit a reference signal. An antenna port can also be defined as the smallest unit for multiplication of precoding vector weights.

[0252] Furthermore, the various embodiments may also be implemented by means of software modules, which are executed by a processor or directly in hardware. A combination of software modules and hardware implementation is also possible. The software modules may be stored on any kind of computer-readable storage medium, for example RAM, EPROM, EEPROM, flash memory, registers, hard disks, CD-ROM, DVD, etc. Furthermore, it should be noted that individual features of the different embodiments may also be the subject of another embodiment, individually or in any combination.

[0253] It will be appreciated by those skilled in the art that various changes and / or modifications may be made to the present disclosure as set forth in the specific embodiments without departing from the concept or scope of the invention as broadly described. The embodiments described herein are therefore to be considered in all respects as illustrative and not restrictive.

Claims

1. A non-terrestrial network (NTN) entity, comprising: a receiver configured to receive, in operation, a channel condition report from a user equipment (UE) providing information about a channel between the UE and the non-terrestrial network (NTN) entity; a transmitter that, in operation, transmits the received channel condition report to a base station; a processor that, during operation, determines updated channel conditions; Equipped with The receiver, in operation, receives scheduling information related to downlink or uplink transmission of data in the UE from the base station; In operation, the processing unit determines whether to adapt a transmit power for the downlink transmission or the uplink transmission in response to the received scheduling information based on the updated channel conditions; When the processing unit determines to adapt the transmission power, the processing unit adapts the transmission power for the downlink transmission or the uplink transmission. NTN entity.

2. the scheduling information is for downlink transmission, and the receiver, in operation, receives downlink data from the base station in association with the scheduling information for the downlink transmission; and adapting the transmit power by the processing unit includes adapting the transmit power of the downlink transmission of the received downlink data. and wherein the transmitter, in operation, performs the downlink transmission of the downlink data to the UE in accordance with scheduling information for the downlink transmission and based on the adapted transmit power. The NTN entity of claim 1 .

3. In operation, the processing unit performs an estimation as to whether a scheduled downlink transmission of the downlink data to the UE will be successful based on the updated channel conditions; If the determined estimation is that the scheduled downlink transmission will not be successful, the transmitter, in operation, transmits a negative acknowledgement for the scheduled downlink transmission to the base station; the transmitter performs the scheduled downlink transmission of the downlink data to the UE. The NTN entity of claim 2.

4. The processing unit, in operation, determines whether to cancel the scheduled downlink transmission of the downlink data to the UE based on the determined estimation; if it is determined that the scheduled downlink transmission is to be canceled, the scheduled downlink transmission is not performed, and the transmission of the negative acknowledgement by the transmitter is performed; if it is determined not to cancel the scheduled downlink transmission, the scheduled downlink transmission of the downlink data to the UE is performed; The determination by the processing unit determines to cancel the scheduled downlink transmission of the downlink data to the UE when the UE is out of coverage of the NTN entity, and the transmission unit, in operation, forwards the downlink data to another NTN entity that is a target of handover of the UE from the NTN entity to the other NTN entity. The NTN entity of claim 3.

5. and wherein the processing unit, in operation, determines a priority associated with the downlink data to be transferred to the UE, and wherein the decision whether to adapt the transmit power of the scheduled downlink transmission takes into account the priority associated with the downlink data. the information regarding the priority associated with the downlink data is included together with the downlink data or together with the downlink transmission scheduling information regarding the downlink transmission of the downlink data; The NTN entity of claim 3.

6. the scheduling information is for uplink transmission; and adapting the transmit power by the processing unit includes adapting the transmit power for the uplink transmission of uplink data. The NTN entity of claim 1 .

7. the received scheduling information for the uplink transmission includes a plurality of different uplink scheduling information, the different uplink scheduling information differing from each other at least in a transmit power value; the adapting of the transmit power by the processing unit includes selecting uplink scheduling information having a most appropriate transmit power based on the updated channel conditions; The transmitter, in operation, transmits the selected uplink scheduling information to the UE. The NTN entity of claim 6.

8. the received scheduling information for the uplink transmission indicates a transmit power value of the scheduled uplink transmission; the adapting of the transmit power by the processing unit includes adapting the value of the transmit power indicated by scheduling information for the uplink transmission to a different value based on the updated channel conditions; the transmitter, in operation, transmits to the UE scheduling information for the uplink transmission having the different values ​​of the transmit power. The NTN entity of claim 6.

9. In operation, the processing unit performs an estimation based on the updated channel conditions as to whether a scheduled uplink transmission of the uplink data by the UE will be successful; If the determined estimation is that the scheduled uplink transmission will not be successful, the transmitter, in operation, transmits a negative acknowledgement for the scheduled uplink transmission to the base station; The transmitter transmits scheduling information for the uplink transmission to the UE. The NTN entity of claim 6.

10. The processing unit, in operation, determines whether to cancel the scheduled uplink transmission of the uplink data by the UE based on the determined estimation; if it is determined to cancel the scheduled uplink transmission, scheduling information for the uplink transmission is not transmitted to the UE; If it is determined not to cancel the scheduled uplink transmission, scheduling information for the uplink transmission is transmitted to the UE. The NTN entity of claim 9.

11. In operation, the receiver monitors a negative acknowledgement received from the UE for a previous downlink transmission from the NTN entity to the UE; the adaptation of the transmission power by the processing unit takes into account the monitored negative acknowledgements and negative acknowledgements for previous uplink transmissions from the UE to the NTN entity; If the amount of monitored negative acknowledgements is greater than a NACK threshold, the adaptation of the transmit power increases the transmit power. The NTN entity of claim 1 .

12. adapting the transmit power includes increasing or decreasing the transmit power; If the updated channel conditions indicate worse channel conditions than the previous channel conditions provided to the base station, the transmit power is increased; the determination of whether to adapt the transmit power for a scheduled downlink or uplink transmission is further based on minimum transmission-related parameters to be met for the scheduled transmission. The NTN entity of claim 1 .

13. and / or wherein the receiver, in operation, receives an updated channel condition report from the UE, and the determination of the updated channel conditions by the processor is performed based on the received updated channel condition report. the processing unit estimating the updated channel conditions from one or more of measurements performed on the channel, feedback on scheduled downlink transmissions, and information about the location of the UE. The NTN entity of claim 1 .

14. The receiver, in operation, receives decoded updated channel condition reports from other NTN entities that have the capability to decode the updated channel condition reports and have a transmission link to the NTN entity; If the NTN entity cannot decode the updated channel condition report, the transmitter, in operation, forwards the updated channel condition report to the other NTN entity; The transmitter does not forward the updated channel condition report to the base station. The NTN entity of claim 13.

15. The processing unit, in operation, determines dedicated uplink radio resources to be allocated to the UE for transmitting the updated channel condition report to the NTN entity, and the transmitting unit, in operation, provides uplink resource information to the UE regarding the determined dedicated uplink radio resources; determining the dedicated uplink radio resource by the processing unit is performed such that the dedicated uplink radio resource is determined from a pool of uplink radio resources allocated by the base station; wherein the processing unit, in operation, determines dedicated downlink radio resources to be used by the NTN entity for transmitting to the UE reference signals for use in determining updated channel conditions, and wherein the determination of the dedicated downlink radio resources by the processing unit is performed such that the dedicated downlink radio resources are determined from a pool of downlink radio resources allocated by the base station. The NTN entity of claim 13.

16. the content of the updated channel condition report is different from the content of the channel condition report; the updated channel condition report provides an indication of whether channel conditions have deteriorated compared to channel conditions indicated by a previously received channel condition report; The receiver performs energy detection to detect the presence of the updated channel condition report, the presence of the updated channel condition report indicating a deterioration of the channel condition compared to the channel condition indicated by the previously received channel condition report, or a specific situation at the UE, including the UE being out of coverage of the NTN entity; The updated channel condition report indicates at least one of a current location of the UE, a current direction of movement of the UE, and a velocity of the UE. The NTN entity of claim 13.

17. A user equipment (UE), a transmitter that, when operational, transmits a channel condition report to a non-terrestrial network (NTN) entity providing information about a channel between the user equipment (UE) and the NTN entity; a processor that, in operation, determines updated channel conditions of the channel between the UE and the NTN entity; a receiver configured to receive, in operation, uplink scheduling information for uplink transmission of uplink data from the UE to the NTN entity from the NTN entity; Equipped with The processing unit, in operation, determines whether to adapt a transmit power of the uplink transmission of the uplink data based on the updated channel conditions; When the processing unit determines that the transmission power should be adapted, the processing unit adapts the transmission power; and wherein the transmitter, in operation, performs the uplink transmission of the uplink data to the NTN entity in accordance with the received scheduling information for uplink transmission and based on the adapted transmit power. UE.

18. In operation, the processing unit determines whether to cancel a scheduled uplink transmission of the uplink data to the NTN entity based on the updated channel conditions; if it is determined to cancel the scheduled uplink transmission, the scheduled uplink transmission is not performed; if it is determined not to cancel the scheduled uplink transmission, the scheduled uplink transmission is performed.

18. The UE of claim 17.

19. the determining whether to adapt the transmit power of a scheduled uplink transmission of the uplink data takes into account a priority of the uplink data; the determination of whether to adapt the transmit power of the scheduled uplink transmission is further based on minimum transmission-related parameters to be met for the scheduled uplink transmission.

18. The UE of claim 17.

20. The processing unit, in operation, determines whether to send an updated channel condition report to the NTN entity, the updated channel condition report indicating the updated channel condition; If the determination of the processing unit determines to transmit the updated channel condition report, the transmitting unit, in operation, transmits the updated channel condition report to the NTN entity; The determination by the processing unit of whether to transmit the updated channel condition report includes at least one condition being satisfied, and one of the at least one condition being that the channel condition has deteriorated compared to the channel condition indicated by a previously transmitted channel condition report.

18. The UE of claim 17.

21. In operation, the receiver receives uplink resource information from the NTN entity indicating uplink radio resources usable by the UE for transmitting the updated channel condition report to the NTN entity; the transmission of the updated channel condition report by the transmitter uses the indicated uplink radio resource.

21. The UE of claim 20.

22. the transmitter, in operation, transmits the updated channel condition report to another NTN entity, the other NTN entity having the capability to decode the updated channel condition report and having a transmission link to the NTN entity; the UE is simultaneously connected to the NTN entity and the other NTN entity; 21. The UE of claim 20.

23. The receiver, in operation, receives a downlink data transmission from the NTN entity; The receiver, in operation, receives a NACK notification from the NTN entity indicating that a negative acknowledgement for the downlink data transmission has already been transmitted to a base station; and wherein the processing unit, in operation, determines not to transmit a negative acknowledgement for the received downlink data transmission even if the received downlink data transmission is not successfully decoded.

18. The UE of claim 17.

24. the content of the updated channel condition report is different from the content of the channel condition report; the updated channel condition report provides an indication of whether channel conditions have deteriorated compared to the channel conditions indicated by the previously transmitted channel condition report; the transmitter performs the transmission of the updated channel condition report such that the receiver of the NTN entity can detect the presence of the transmission of the updated channel condition report based on energy detection, and the transmitting of the updated channel condition report indicates a deterioration of the channel condition compared to the channel condition indicated by the previously received channel condition report; The updated channel condition report indicates at least one of a current location of the UE, a current direction of movement of the UE, and a velocity of the UE.

21. The UE of claim 20.

25. a receiver that, in operation, receives a channel condition report from a user equipment (UE) and a non-terrestrial network (NTN) entity, the channel condition report providing information about a channel between the UE and the NTN entity; a processor for, in operation, preparing, based on the received channel condition report, a plurality of different uplink scheduling information for uplink data transmission by the UE, the different uplink scheduling information differing from one another in at least a transmit power value; a transmitter that, in operation, transmits the prepared plurality of different uplink scheduling information to the NTN entity; A base station comprising:

26. The processing unit, in operation, determines a pool of radio resources usable by the UE for sending updated channel condition reports to the NTN entity; The transmitter, when operating, transmits information regarding the determined pool of radio resources to the NTN entity; The transmitter, in operation, transmits a configuration message to the NTN entity to configure the NTN entity not to forward the updated channel condition report to the base station.

26. The base station of claim 25.

27. In operation, the transmitter transmits a configuration message to another NTN entity that has the capability to decode the updated channel condition report and has a transmission link to the NTN entity, the configuration message configuring the other NTN entity to receive and decode the updated channel condition report from the UE and to forward the updated channel condition report to the NTN entity serving the UE; the configuration message indicating radio resources available for use by the UE for transmitting the updated channel condition report.

26. The base station of claim 25.

28. The receiver, in operation, receives a negative acknowledgement from the NTN entity for a previously scheduled downlink transmission of downlink data to the UE, the negative acknowledgement further indicating that the NTN entity has canceled the previously scheduled downlink transmission of the downlink data to the UE; The processing unit, in operation, determines, based on the negative acknowledgement, to perform a retransmission of the downlink data to the UE as if the retransmission is a first transmission of the downlink data and is not a retransmission; The transmitter, in operation, retransmits downlink scheduling information and the downlink data to the NTN entity to be forwarded to the UE; the downlink scheduling information for the downlink data indicates that the transmitted downlink data is new downlink data, as if the transmitted downlink data is a first transmission of the downlink data and is not a retransmission; 26. The base station of claim 25.

29. The receiver, in operation, receives a negative acknowledgement from the NTN entity for a previously scheduled downlink transmission of downlink data to the UE; The processing unit, in operation, determines to perform retransmission of the downlink data to the UE based on the negative acknowledgement; and wherein the transmitter, in operation, retransmits downlink scheduling information and the downlink data to the NTN entity to be forwarded to the UE, wherein the retransmission uses a different version of the downlink data for the retransmission.

26. The base station of claim 25.

30. The transmitter, in operation, transmits information regarding the priority of the downlink data to the NTN entity; the information regarding the priority is included together with the downlink data or together with the downlink scheduling information regarding the transmission of the downlink data; and wherein the transmitter, in operation, transmits minimum transmission-related parameters to the NTN entity, the minimum transmission-related parameters indicating minimum conditions to be met by a scheduled transmission, and used in a process of determining whether to adapt the transmission power for the scheduled transmission.

29. The base station of claim 28.

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