Reducing the overhead of adjacent cell signaling in non-terrestrial networks.

Abstract

In one embodiment, a user device (UE) is provided, comprising: a transceiver that receives system information during operation; and a circuit that, during operation, determines a first information element from the system information that identifies the setting parameters of a first satellite; and determines a second information element from the system information and, with reference to the setting parameters of the first satellite, that identifies the setting parameters of a second satellite different from those of the first satellite. A corresponding base station and a method including steps performed between the UE and the base station are also provided.

Description

Technical Field

[0001] The present disclosure relates to the transmission of system information regarding a non-terrestrial network. In particular, the present invention relates to apparatuses and methods for generating, signaling, receiving, and / or utilizing system information regarding a non-terrestrial network.

Background Art

[0002] Currently, the 3rd Generation Partnership Project (3GPP) (registered trademark) is working on the technical specifications of the next-generation cellular technology, also known as the 5th generation (5G) or New Radio (NR).

[0003] One objective is to provide a single technical framework that can accommodate all usage scenarios, requirements, and deployment scenarios, including at least enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine type communication (mMTC). For example, eMBB deployment scenarios may include indoor hotspots, high-density urban areas, rural areas, urban macro, and high-speed environments. URLLC deployment scenarios may include industrial control systems, mobile healthcare (remote monitoring, diagnosis, and treatment), real-time vehicle control, and wide-area monitoring and control systems for smart grids. mMTC deployment scenarios may include scenarios with many devices involving non-time-critical data transfer, such as smart wearable terminals and sensor networks. The eMBB service and the URLLC service are similar in that both require extremely wide bandwidths, but the URLLC service is different in that ultra-low latency may preferably be required.

[0004] The second objective is to achieve forward compatibility. Backward compatibility with 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.

[0005] One of the notable features of 5G is the introduction of non-terrestrial networks (NTN), including satellites, in the communication path between user equipment and the network. Due to its broad service coverage and reduced vulnerability to physical attacks and natural disasters in space and on aircraft, NTN can facilitate the deployment of NR services in unserviced areas (e.g., isolated or remote areas, on aircraft or ships) and unserviced areas (e.g., suburbs and rural areas) that are not covered by terrestrial NR networks. Furthermore, NTN can enhance the reliability of NR services by providing continuity of service for passengers on moving platforms and ensuring service availability everywhere, especially for critical communications.

[0006] These advantages relate to either standalone non-terrestrial networks or integrated networks combining terrestrial and non-terrestrial networks, and can impact coverage, user bandwidth, system capacity, and service reliability or availability. Further improvements by NTN are desired to enhance the coverage and efficiency of communication systems. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] 3GPP TS 38.300 v16.3.0 [Non-Patent Document 2] 3GPP TS 38.211 v16.3.0 [Non-Patent Document 3] ITU-R M.20183 [Non-Patent Document 4] 3GPP TR 38.913 v16.0.0 [Non-Patent Document 5] 3GPP TS 23.501 v16.6.0 [Non-Patent Document 6] 3GPP TR 38.811 v15.4.0 [Non-Patent Document 7] 3GPP TR 38.821 v16.1.0 [Non-Patent Document 8] 3GPP TS 38.321 v17.3.0 [Non-Patent Document 9] 3GPP TS 38.401 v17.3.0 [Non-Patent Document 10] 3GPP TS 38.331 v17.3.0 [Overview of the project]

[0008] One non-limiting and exemplary embodiment contributes to the efficient transmission and reception of system information related to a non-terrestrial network.

[0009] In one embodiment, the technology disclosed herein features a user device (UE) comprising: a transceiver that receives system information during operation; and a circuit that, during operation, determines a first information element from the system information that identifies the setting parameters of a first satellite, and determines a second information element from the system information and by referring to the setting parameters of the first satellite that identifies the setting parameters of a second satellite different from the first satellite.

[0010] It should be noted that general or specific embodiments can be implemented as systems, methods, integrated circuits, computer programs, storage media, or any selective combination thereof.

[0011] For example, an integrated circuit can control the processing of a UE or network node.

[0012] Further advantages and effects in an embodiment of the present disclosure will be clarified from the specification and drawings. Such advantages and / or effects are respectively provided by several embodiments and features described in the specification and drawings, but not all of them necessarily need to be provided to obtain one or more identical features.

Brief Description of Drawings

[0013] The following exemplary embodiments will be described in more detail with reference to the accompanying drawings. [Figure 1] A block diagram showing an exemplary architecture of a 3GPP NR system. [Figure 2] A block diagram showing the functional split between NG-RAN and 5GC. [Figure 3] A message sequence diagram of the RRC connection setup / reset procedure. [Figure 4] A schematic diagram showing usage scenarios of enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable and low-latency communication (URLLC). [Figure 5] A block diagram showing an exemplary 5G system architecture for a non-roaming scenario. [Figure 6] A block diagram showing an exemplary NG RAN architecture based on a transparent relay satellite. [Figure 7] A block diagram showing an exemplary NG RAN architecture based on a regenerative relay satellite. [Figure 8] A block diagram showing an exemplary scenario where several UEs receive services from a satellite. [Figure 9] A schematic diagram showing an exemplary scenario of a satellite orbiting the Earth. [Figure 10] A schematic diagram showing orbital parameters that can be used to explain the position of a satellite. [Figure 11] A schematic diagram showing an exemplary satellite network having a regular distribution of satellites on orbits and satellite orbits. [Figure 12] A block diagram showing the structures of a UE and a BS that can communicate with each other. [Figure 13] A block diagram showing the functional structure of a memory module containing code instructions executed by a circuit including one or more processors for UE and BS. [Figure 14] A schematic diagram illustrating an exemplary scenario in which two satellites in a common orbit are described by system information. [Figure 15] A schematic diagram illustrating an exemplary scenario of two adjacent orbits described by system information. [Figure 16] A schematic diagram illustrating an exemplary scenario in which multiple satellites orbiting in adjacent orbits are described in the system information. [Figure 17] A schematic diagram illustrating an exemplary scenario of multiple evenly distributed satellites whose positions are described in the system information. [Figure 18] A flowchart showing the procedure performed on the UE side. [Figure 19] A flowchart showing the method used on the BS side. [Figure 20] A flowchart illustrating an example of the method used on the UE side. [Modes for carrying out the invention]

[0014] <5G NR System Architecture and Protocol Stack> In particular, the system architecture as a whole assumes an NG-RAN (Next Generation - Radio Access Network) equipped with gNBs. The gNBs provide the UE-side termination for the user plane (SDAP / PDCP / RLC / MAC / PHY) and control plane (RRC) protocols of the NG radio access. The gNBs are connected to each other by Xn interfaces. Furthermore, the gNBs are connected to the NGC (Next Generation Core) by Next Generation (NG) interfaces, more specifically to the AMF (Access and Mobility Management Function) (e.g., a specific core entity performing AMF) by NG-C interfaces, and to the UPF (User Plane Function) (e.g., a specific core entity performing UPF) by NG-U interfaces. The NG-RAN architecture is shown in Figure 1 (see, for example, Section 4 of Non-Patent Document 1).

[0015] The NR user plane protocol stack (see, for example, Section 4.4.1 of Non-Patent Document 1) includes the PDCP (Packet Data Convergence Protocol (see Section 6.4 of Non-Patent Document 1)) sublayer, RLC (Radio Link Control (see Section 6.3 of Non-Patent Document 1)) sublayer, and MAC (Medium Access Control (see Section 6.2 of Non-Patent Document 1)) sublayer, which are terminated on the network side in gNB. In addition, a new access layer (AS: Access Stratum) sublayer (SDAP: Service Data Adaptation Protocol) is introduced on top of PDCP (see, for example, Section 6.5 of Non-Patent Document 1). Furthermore, the control plane protocol stack is defined for NR (see, for example, Section 4.4.2 of Non-Patent Document 1). An overview of the Layer 2 functions is described in Section 6 of Non-Patent Document 1. The functions of the PDCP, RLC, and MAC sublayers are enumerated in Sections 6.4, 6.3, and 6.2 of Non-Patent Document 1, respectively. The functions of the RRC layer are listed in Section 7 of Non-Patent Document 1.

[0016] For example, the Medium-Access-Control layer handles the multiplexing of logical channels, scheduling, and scheduling-related functions, including handling various neural networks.

[0017] For example, the physical layer (PHY) is responsible for coding, PHY HARQ processing, modulation, multi-antenna processing, and mapping signals to appropriate physical time-frequency resources. The physical layer also handles the 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 particular transport channel, and each transport channel is mapped to a corresponding physical channel. For example, physical channels include uplink physical channels such as PRACH (Physical Random Access Channel), PUSCH (Physical Uplink Shared Channel), and PUCCH (Physical Uplink Control Channel), and downlink physical channels such as PDSCH (Physical Downlink Shared Channel), PDCCH (Physical Downlink Control Channel), and PBCH (Physical Broadcast Channel).

[0018] Use cases / deployment scenarios for NR can include enhanced mobile broadband (eMBB), ultra-high reliability, low latency (URLLC), and massive simultaneous connection (mMTC), all of which have diverse requirements in terms of data rate, latency, and coverage. For example, eMBB is expected to support peak data rates (20 Gbps on the downlink and 10 Gbps on the uplink) and effective (user-experienced) data rates approximately three times that of IMT-Advanced. URLLC, on the other hand, has more stringent requirements, including ultra-low latency (0.5 ms for both UL and DL for user plane latency) and high reliability (1-10 ms within 1 ms). -5 ) is required. Finally, mMTC preferably has a high connectivity density (1,000,000 devices / km in urban environments). 2), wide coverage in harsh environments, and extremely long-lasting batteries (15 years) for low-cost devices may be required.

[0019] Therefore, an OFDM neurology suitable for one use case (e.g., subcarrier spacing, OFDM symbol length, cyclic prefix (CP) length, number of symbols per scheduling interval) may not be effective for other use cases. For example, low-latency services may preferably require a shorter symbol length (and thus a larger subcarrier spacing) and / or fewer symbols per scheduling interval (also known as TTI) than mMTC services. Furthermore, deployment scenarios with large channel delay spreads may preferably require a longer CP length than scenarios with shorter delay spreads. The subcarrier spacing should be optimized on a case-by-case basis so that similar CP overhead is maintained. There may be one or more subcarrier spacing values ​​supported by NR. Currently, subcarrier spacings of 15kHz, 30kHz, 60kHz, etc. are considered. The symbol length Tu and subcarrier spacing Δf are directly related by the equation Δf = 1 / Tu. Similar to LTE systems, the term “resource element” can be used to mean the smallest resource unit comprised of one subcarrier relative to the length of one OFDM / SC-FDMA symbol.

[0020] In the new 5G-NR wireless system, resource grids for subcarriers and OFDM symbols are defined for each neurology and each carrier, separately for the uplink and downlink. Each element of the resource grid is called a resource element and is identified based on the frequency index in the frequency domain and the symbol position in the time domain (see Non-Patent Literature 2 (e.g., Section 4)). For example, downlink and uplink transmissions are set to frames with a time length of 10ms. Each frame consists of 10 subframes, each with a time length of 1ms. In the implementation of 5G NR, the number of consecutive OFDM symbols per subframe depends on the setting of the subcarrier interval. For example, with a subcarrier interval of 15kHz, a subframe has 14 OFDM symbols (similar to an LTE-compliant implementation assuming a normal cyclic prefix). On the other hand, with a subcarrier interval of 30kHz, a subframe has two slots, each slot containing 14 OFDM symbols.

[0021] <Functional division between NG-RAN and 5GC in 5G NR> Figure 2 shows the functional partitioning between NG-RAN and 5GC. The logical nodes of NG-RAN are gNB or ng-eNB. 5GC has logical nodes AMF, UPF, and SMF.

[0022] In particular, gNB and ng-eNB host the following main functions: - Radio resource management functions such as radio bearer control, radio admission control, connection mobility control, and dynamic allocation (scheduling) of resources to UEs on both uplink and downlink; - Compression, encryption, and integrity protection of the IP header of the data; - Selection of the AMF when the UE attaches if routing to the AMF cannot be determined from the information provided by the UE; - Routing user plane data toward UPF; - Routing of control plane information to AMF; - Setup and release of connections; - Scheduling and sending paging messages; - Scheduling and transmission of system notification information (originating from AMF or Operation, Admission, Maintenance functions (OAM)); - Setting up measurements and reporting for mobility and scheduling; - Transport-level packet marking on the uplink; - Session management; - Support for network slicing; - QoS flow management and mapping to data wireless bearers; - Support for UEs in the RRC_INACTIVE state; - Non-Access Stratum (NAS) message delivery function; - Sharing of wireless access network; - Dual connectivity; - Close cooperation between NR and E-UTRA.

[0023] The Access and Mobility Management Function (AMF) hosts the following main functions: - A function to terminate signaling in the Non-Access Stratum (NAS); - Security of NAS signaling; - Security control at the Access Layer (AS); - Core Network (CN) node-to-node signaling for mobility between 3GPP access networks; - Reachability of the UE in idle mode (including control and execution of paging retransmissions); - Management of registration areas; - Support for intra-system and inter-system mobility; - Access authentication; - Access authorization including roaming permission checks; - Mobility management and control (enrollment and policies); - Support for network slicing; - Selection of Session Management Function (SMF).

[0024] Furthermore, the User Plane Function (UPF) hosts the following main functions: - Anchor points for mobility within RATs / inter-RATs (where applicable); - External PDU (Protocol Data Unit) session points for interconnection with data networks; - Routing and forwarding of packets; - Packet inspection and enforcement of policy rules in the user plane; - Reporting traffic usage; - Uplink classifier that supports routing of traffic flow to data networks; - 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 upstream link traffic (mapping to SDF QoS flow); - Buffering of downlink packets and triggering of downlink data notifications.

[0025] 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 of the control part; - Notification of downlink data.

[0026] <Procedures for Setup and Reconfiguration of RRC Connection> Figure 3 shows some of the interactions between the UE, gNB, and AMF (5GC entity) in the NAS part when the UE transitions from RRC_IDLE to RRC_CONNECTED (see Non-Patent Document 1).

[0027] RRC is a higher-layer signaling protocol used for configuring UEs and gNBs. Specifically, this transition requires AMF to prepare UE context data (which includes, for example, PDU session context, security key, UE radio capability, UE security capability, etc.) and send it to the gNB along 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 to the gNB with a SecurityModeComplete message. Subsequently, the gNB sends an RRCReconfiguration message to the UE, and upon receiving an RRCReconfigurationComplete from the UE, the gNB reconfigures itself to set up the Signaling Radio Bearer 2 (SRB2) and Data Radio Bearer (DRB). For signaling-only connections, the RRCReconfiguration step is omitted because SRB2 and DRB are not set up. Finally, gNB notifies AMF that the setup procedure is complete with an Initial Context Setup Response.

[0028] This disclosure provides a 5th Generation Core (5GC) entity (e.g., AMF, SMF, etc.) comprising a control circuit that establishes a Next Generation (NG) connection with a gNB during operation, and a transmission unit that sends an initial context setup message to the gNB via the NG connection during operation so that a signaling radio bearer between the gNB and the user equipment (UE) is set up. Specifically, the gNB transmits Radio Resource Control (RRC) signaling, including an Information Element (IE), to the UE via the signaling radio bearer. The UE then transmits on the uplink or receives on the downlink based on the resource allocation setting.

[0029] <IMT Usage Scenarios from 2020 Onward> Figure 4 shows 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 specification development for enhanced mobile-broadband (eMBB) has been completed. Current and future work will include expanding eMBB support, as well as standardization for ultra-high reliability low latency (URLLC) and massive simultaneous connection (mMTC). Figure 4 shows some examples of anticipated use scenarios for IMT beyond 2020 (see, for example, Figure 2 in Non-Patent Document 3).

[0030] URLLC use cases have stringent performance requirements such as throughput, latency, and availability, and URLLC use cases are envisioned as enabling future applications such as wireless control of industrial production or manufacturing processes, telemedicine surgery, automation of power transmission and distribution in smart grids, and traffic safety. The ultra-high reliability of URLLC is supported by identifying technologies that meet the requirements set out in Non-Patent Document 4. In NR URLLC in Release 15, a key requirement is that the target user plane latency is 0.5 ms for UL (uplink) and 0.5 ms for DL ​​(downlink). A typical URLLC requirement for a single packet transmission is a block error rate (BLER) of 1E-5 for a 32-byte packet size when the user plane latency is 1 ms.

[0031] From a physical layer perspective, reliability can be improved in many ways. Current room for reliability improvement includes defining a separate CQI table for URLLC, a more compact DCI format, and repeated transmission of PDCCH. However, this room for improvement could expand towards achieving ultra-high reliability as NR becomes more stable and developed (in terms of critical requirements for NR URLLC). Specific use cases for NR URLLC in Release 15 include augmented reality / virtual reality (AR / VR), e-health, e-safety, and mission-critical applications.

[0032] Furthermore, the technical enhancements targeted by NR URLLC aim to improve latency and reliability. Technical enhancements for latency improvement include configurable neurology, non-slot-based scheduling with flexible mapping, grant-free (configured-grant) uplink, slot-level repeat transmission on data channels, and preemption on downlink. Preemption means that a transmission for which a resource has already been allocated is stopped, and that allocated resource is used for other transmissions with lower latency / higher priority requirements that are requested later. Thus, transmissions that were already permitted are replaced by later transmissions. Preemption is applicable regardless of the specific service type. For example, a transmission of service type A (URLLC) may be replaced by a transmission of service type B (eMBB, etc.). Technical enhancements for reliability improvement include a dedicated CQI / MCS table for the 1E-5 target BLER.

[0033] A key characteristic of mMTC (massive machine type communication) use cases is the extremely large number of connected devices that typically transmit relatively small amounts of data that are less susceptible to latency. These devices are required to be low-cost and have very long battery life. From a noise reduction (NR) perspective, utilizing a very narrow bandwidth is one solution that saves power from the user interface (UE) and extends battery life.

[0034] As mentioned above, the scope of reliability improvements in NR is expected to broaden. High or very high reliability is a critical requirement in all cases, and especially for URLLC and mMTC. Several mechanisms can improve reliability from both a radio and network perspective. Generally, there are two to three key areas that can help improve reliability. These areas include compact control channel information, data channel / control channel repetition, and diversity in the frequency, time, and / or spatial domains. These areas are generally applicable to reliability improvements regardless of the specific communication scenario.

[0035] Regarding NR URLLC, further use cases with more stringent requirements are envisioned, such as factory automation, transportation, and power distribution. These stringent requirements include high reliability (up to 10^6 levels), high availability, packet size up to 256 bytes, and time synchronization down 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 short latency of approximately 0.5 ms to 1 ms (especially 0.5 ms latency in the target user plane)).

[0036] Furthermore, for NR URLLC, several technical extensions are possible from the perspective of the physical layer. These technical extensions include the extension of the PDCCH (Physical Downlink Control Channel) related to compact DCI, the repeated transmission of the PDCCH, and the increased monitoring of the PDCCH. In addition, the extension of UCI (Uplink Control Information) is related to the extension of enhanced HARQ (Hybrid Automatic Repeat Request) and CSI feedback. There may also be extensions of the PUSCH related to mini-slot level hopping and extensions of retransmission / repeated transmission. The term "mini-slot" refers to a transmission time interval (TTI: Transmission Time Interval) that contains fewer symbols than a slot (a slot has 14 symbols).

[0037] <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 differentiation in a PDU session. A QoS flow is identified within a PDU session by a QoS flow ID (QFI: QoS Flow ID) that is carried in an encapsulation header via the NG-U interface.

[0038] For each UE, the 5GC establishes one or more PDU sessions. For each UE, the NG-RAN establishes at least one Data Radio Bearers (DRB) in accordance with the PDU session, as shown above, for example, referring to Figure 3. Additional DRBs for the QoS flow of that PDU session can be configured later (when this is done is up to the NG-RAN). The NG-RAN maps packets belonging to various PDU sessions to various DRBs. NAS-level packet filters in the UE and 5GC associate UL packets and DL packets with QoS flows, while AS-level mapping rules in the UE and NG-RAN associate UL QoS flows and DL QoS flows with DRBs.

[0039] Figure 5 shows the non-roaming reference architecture for 5G NR (see Section 4.2.3 of Non-Patent Document 5). An Application Function (AF) (for example, an external application server hosting 5G services, as illustrated in Figure 4) interacts with the 3GPP core network to provide services, such as influencing traffic routing, accessing the Network Exposure Function (NEF), or interacting with the policy framework for policy control (e.g., QoS control) (see Policy Control Function (PCF)). Based on operator deployment, Application Functions considered trusted by the operator can interact directly with the relevant Network Functions. Application Functions not authorized by the operator to directly access the Network Functions interact with the relevant Network Functions using an external exposure framework via the NEF.

[0040] Figure 5 further illustrates the functional units of the 5G architecture, namely the 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 services, internet access, or third-party services). All or part of the core network functions and application services may be deployed and operated in a cloud computing environment.

[0041] Accordingly, this disclosure provides an application server (e.g., AF in a 5G architecture) comprising: a transmitting unit that, in operation, transmits a request including QoS requirements for at least one of the URLLC service, eMBB service, and mMTC service to at least one of the 5GC functions (e.g., NEF, AMF, SMF, PCF, UPF, etc.) to establish a PDU session including a radio bearer between a gNB and a UE in accordance with QoS requirements; and a control circuit that, in operation, performs the service using the established PDU session.

[0042] <Sending system information> System information is broadcast information for the downlink transmitted by the base station (gNB in ​​5G, generally a network node). System information contains information necessary for the UE to establish a connection with the base station. In 5G, the UE reads system information for cell camping when powered on, and system information for cell selection and re-selection when in RRC_IDLE mode. System information provides all the details necessary to access the network, such as system frame number, system bandwidth, PLMN, and cell selection and re-selection thresholds.

[0043] System information is structured into Master Information Blocks (MIBs) and System Information Blocks (SIBs). Various types of information are contained within the SIB. In this disclosure, relevant information may include information related to NTN transmission, as described later. MIB information is transmitted (broadcast) via BCH and PBCH channels, while SIBs are transmitted via DL-SCH and PDSCH channels.

[0044] Generally, system information is transmitted periodically or on request (so that newly connected terminals can acquire it). The periodic schedule for transmitting system information can be set by the RRC. In particular, SIB1 (referenced by the MIB) transmits scheduling information that identifies, for example, the system information window (the repetition period of the system information transmission pattern), several transmission parameters for receiving system information (e.g., physical layer parameters), and the mapping (transmission pattern) of SIBs within the system information window.

[0045] <Non-terrestrial network (NTN)> A non-terrestrial network refers to a network or network segment that uses RF resources mounted on airborne or space-based entities for transmission. Space-based entities include, for example, satellites (including low-earth orbit (LEO), medium-earth orbit (MEO), geostationary orbit (GEO), and highly elliptical orbit (HEO) satellites). Airborne entities include, for example, high-altitude platforms (HAPs) and unmanned aircraft systems (UAS), including lighter-than-air (LTA) and heavier-than-air (HTA) UAS, all of which operate quasi-regularly between altitudes of 8km and 50km.

[0046] 3GPP has considered and described the operation of NR-based radio on non-terrestrial networks (NTN) (see, for example, Non-Patent Document 6, "Study on New Radio (NR) to support non-terrestrial networks," and Non-Patent Document 7, "Solutions for NR to support non-terrestrial networks").

[0047] NTN typically comprises the following system elements: NTN terminals pointing to 3GPP UEs, or terminals specific to the satellite system if the satellite does not directly service 3GPP UEs; service links pointing to radio links between user equipment and space / air platforms; air platforms carrying payloads; gateways connecting space / air platforms to the core network; and feeder links pointing to radio links between gateways and space / air platforms.

[0048] The platform can implement either transparent repeater payload transmission or regenerative repeater payload transmission. In transparent repeater payloads, the payload remains unchanged, and the platform functions as a repeater by filtering, transforming, and amplifying the radio signal. In regenerative repeater payloads, the platform has some or all of the base station functions. In addition to filtering, transforming, and amplifying radio frequencies, the platform may perform demodulation / modulation, switching / routing, and coding / decoding. Inter-Satellite Links (ISLs) may optionally be used to form a constellation of satellites. An Inter-Satellite Link (ISL) is a transport link between satellites.

[0049] Figure 6 illustrates a non-terrestrial network scenario in which transmission to and from the terminal (UE) occurs via a remote radio unit including a satellite and an NTN gateway. The gNB is located at the gateway as a scheduling device. The satellite payload performs frequency conversion and radio frequency amplification in both the uplink and downlink directions. Thus, the satellite relays the NR 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. A satellite in this configuration is called a through-relay satellite.

[0050] Figure 7 illustrates a non-terrestrial network scenario in which transmission between the terminal (UE) and the satellite takes place via a satellite including a gNB as a scheduling device. Satellites in this configuration are called regenerative relay satellites. According to one embodiment (see Non-Patent Document 8, Section 5.2 "NR; Medium Access Control (MAC) protocol specification"), the NG-RAN logical architecture described in Non-Patent Document 9 "NG-RAN; Architecture description" is used as the baseline for the NTN scenario. The satellite payload performs 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 on the feeder link between the NTN gateway and the satellite, and the Satellite Radio Interface (SRI) is the transport link between the NTN GW and the satellite.

[0051] Because LEO, MEO, and HEO satellites do not have a fixed position relative to a given point on Earth, the satellite beam corresponding to the cell or physical cell ID (PCI), or the synchronization signal block (SSB) beam of the NR radio system may move across the Earth.

[0052] An NTN scenario that provides cells moving continuously on the Earth (e.g., LEO, MEO, HEO-based NTN) is called an Earth-mobile cell scenario. The continuous movement of cells on the Earth is due to an operation in which satellite beams are fixed to the NTN platform. Therefore, the footprints of cells corresponding to multiple satellite beams or one satellite beam slide on the Earth's surface in accordance with the movement of the NTN platform (e.g., a LEO satellite). This is shown in FIG. 8. The satellite 810 moves at a speed of, for example, 7.6 km / s (indicated by the movement arrow 820). The satellite 810 may provide one or more cells (here, three cells) 890. There is a service link 840 between the UE 850 and the satellite 810. System information, especially the System Information Block (SIB), which may be called NTN-SIB, transmits NTN information. Currently, SIB19 transmits NTN information in 3GPP NTN-NR. The system information is broadcast by the satellite 810. The present disclosure is not limited to a specific network configuration. In some communication systems that may benefit from the present disclosure, the satellite may be controlled to broadcast system information by the gNB 860. There is a delay in the feeder link 830 between the satellite 810 and the gNB 860.

[0053] <NTN Configuration> In the current form, the System Information Block 19 (SIB19) can provide information about the serving cell and information about the adjacent cells of the serving cell, as shown in Non-Patent Document 10, "Radio Resource Control (RRC) protocol specification". The information may be broadcast or communicated via dedicated signaling. An exemplary current part of SIB19 including information elements (IEs) and fields related to NTN adjacent cells is shown below. [Table 1] Here, ntn-NeighCellConfigList and ntn-NeighCellConfigListExt provide a list of NTN neighboring cells, including ntn-Config, carrier frequency, and PhysCellId (physical cell ID). ntn-Config provides parameters for the UE to access NR via NTN access, such as ephemeris data, common timing advance (TA) parameters, k_offset, validity period of UL synchronization information, and epoch, as shown below. [Table 2] Information regarding the satellite's orbit is contained in the ephemeris data (EphemerisInfo). As shown below, the ephemeris data can be represented as (i) position and velocity data, and (ii) orbit data. One of these representations is sufficient to determine the satellite's orbit. [Table 3] As shown in Figure 9, the coordinates of the satellite position (X, Y, Z), the velocity vector (VX, VY, VZ), and the reference time (e.g., epoch time) determine the orbit. Specifically, satellite 910 orbits the Earth 990 in orbit 900, with the geocenter 950 as its center. At a given reference time, the position 930 and velocity 940 characterize the position of satellite 910.

[0054] Note that the "-r17" suffix in some IEs and fields in the copied syntax above simply indicates the release date of the standard; therefore, it is omitted in this specification when referring to these IEs or fields. It may be changed to "-r18," "-r19," etc., in future releases.

[0055] Another possibility is to use orbital parameters. Orbital parameters include, for example, the semi-major axis, eccentricity, inclination angle, right ascension of the ascending node (longitude of the ascending node on the orbital plane), argument of periphery, mean angle of periphery at reference time, and epoch (e.g., the epoch time mentioned above). The first five parameters can determine the orbital plane (orbital plane parameters), while the other two parameters are used to determine the precise satellite position at reference time, e.g., the epoch time (satellite-level parameters).

[0056] Figure 10 shows satellite 110 in orbit 100. Orbit 100 is characterized by its semi-major axis 105 ("semiMajorAxis" field), eccentricity (relationship of the semi-major axis to the semi-minor axis, "eccentricity" field), inclination angle i ("inclination" field), ascending node longitude Ω of the orbital plane ("longitude" field), argument of periapsis ω ("periapsis" field), and angle of periapsis ν ("meanAnomaly" field). In this specification, the term "field" refers to an information element that is a single parameter, rather than a container of further information elements / fields, when referring to 5G syntax and terminology.

[0057] In the NTN system, multiple satellites may share a common orbit. Figure 11 shows an exemplary distribution of satellites (white dots) in orbit around the Earth (white lines). The orbits are arranged such that adjacent orbits are substantially parallel. In such a distribution of satellites, adjacent satellites often share several characteristics. Therefore, some ephemeris parameters may be identical or very similar among adjacent satellites. For example, some elements that are part of the IE ephemerisInfo-r17 of each adjacent cell are not always necessary because they would be repeating information already provided in relation to the ephemerisInfo-r17 of the reference cell. In this specification, “reference cell” means any cell that is defined as the reference for other cells. A serving cell may also function as a reference cell in some cases. However, this disclosure is not limited in this respect, and other cells may be defined as reference cells.

[0058] <Signaling Reduction> For example, for satellites in the same orbit, the parameters within the positionVelocity sequence may be highly correlated. In particular, velocity parameters may be completely or partially identical for all satellites in the same orbit. The positions of satellites in the same orbit may be further defined, for example, by distributing them equally within their orbits. Even satellites in adjacent orbits may have the same or similar velocity and satellite distribution. Accordingly, orbital parameters may be similar or identical for adjacent satellites, for example, satellites in the same orbit or adjacent orbits. For example, parameters that define the orbit, namely the semi-major axis, eccentricity, tilt angle, longitude, and perigee, will be identical for satellites sharing the same orbit. Therefore, to reduce signaling overhead, it may be desirable to utilize the similarity of ephemeris data of adjacent satellites.

[0059] In some embodiments, to facilitate signaling reduction, instead of the unnecessary information described above, signaling to neighboring satellites may be limited to notifying of differences (or, more generally, relationships) between neighboring satellite attributes and reference satellite attributes.

[0060] Figure 12 shows an exemplary User Equipment (UE) 210. The UE 210 comprises a transceiver 240 and a circuit 220 interconnected via an interface 230. The transceiver 240 is configured to receive system information. The transceiver 240 may receive system information by broadcast or by dedicated signaling. In this context, system information refers to information about the system infrastructure, the configuration of the system infrastructure, and / or resources. More specifically, the system information may include information elements (IE) of the RRC protocol, similar to 5G NR. The circuit 220 is configured to determine a first information element from the system information that identifies the configuration parameters of the first satellite.

[0061] The circuit 220 is further configured to determine a second information element that identifies a setting parameter for a second satellite that is different from that of the first satellite, based on system information and by referring to the setting parameters of the first satellite.

[0062] The first satellite can be considered a reference satellite because it serves as the basis for the setting parameters of the other (second) satellite. The first and second satellites may be adjacent satellites. The term adjacent satellite means a satellite that operates a cell adjacent to a cell(s) operated by the reference satellite. For example, adjacent satellites may be satellites immediately before and after the reference satellite in the same orbit, or satellites in two (nearest) adjacent orbits. However, this disclosure is not limited to the first and second satellites being adjacent. Furthermore, satellites that are not adjacent to the reference satellite may also benefit from reduced signaling overhead. For example, as already mentioned, not all satellites in the same orbit are adjacent to the reference satellite, but they can share most of the parameters, such as all the parameters that describe the orbit.

[0063] System information defines the parameters of a serving cell, including the position and / or orbit of the serving satellite that operates (provides) the serving cell; therefore, the serving satellite may be a reference satellite. However, this disclosure is not limited to the serving satellite being a reference satellite. In some embodiments, an information element that identifies which satellite is the reference satellite may be included in the system information that transmits adjacent satellite information. Alternatively, or in addition thereto, the reference satellite may be determined according to a predetermined rule, or a similar rule, such as designating a satellite preceding that particular satellite in the same orbit as the reference satellite for a particular satellite.

[0064] Figure 12 further shows a base station (BS) 290. The base station comprises a transceiver 260 and a circuit 280 interconnected via an interface 270. The transceiver 260 is configured to transmit system information. The circuit 280 is configured to generate system information. The generation of system information includes including a first information element in the system information that identifies the configuration parameters of a first satellite, and including a second information element in the system information. The generation of system information further includes determining a second information element that identifies the configuration parameters of a second satellite, which are different from those of the first satellite, by referring to the configuration parameters of the first satellite.

[0065] The term “configuration parameter” means one or more configuration parameters, i.e., at least one configuration parameter. Generally, the term “information element” refers to an element of protocol syntax (such as the RRC protocol described above) and may (but does not need to) encapsulate further information elements. In a similar context, the term “field” refers to a single parameter provided within the structure of a “sequence” and / or “information element.” The first and second satellites are satellites that provide cellular coverage. Specifically, the first and second satellites operate at least one cell of a radio access network. UE210 may use the first and / or second satellites to access a communication network such as 5G NR. The base station 290 may be located directly on the serving satellite or may control the serving satellite as described above with reference to Figures 6 and 7. In the context of 5G NR, the base station may be a gNB. This disclosure is readily applicable to, but not limited to, 5G NR systems. Any current or future communication system using at least two satellites may benefit from this disclosure.

[0066] As shown in Figure 12, UE210 and BS290 may communicate via channel 250. In particular, BS290 may transmit system information to UE210 via channel 250, which may include a radio channel between the satellite and the UE.

[0067] The transmitting and receiving units (e.g., the UE transmitting and receiving unit 240 and the BS transmitting and receiving unit 260) may be any receiving and / or transmitting units including, for example, one or more antennas and corresponding amplification and modulation / demodulation units (up-conversion to the system carrier / down-conversion from the system carrier). The transmitting and receiving units may be controlled by a control module to perform the transmission and / or reception of specific data at specific timings and with specific resources. Such a control module may be part of circuits 220, 280.

[0068] The circuits (such as circuit 220 of UE and circuit 280 of BS) may include one or more processors, one or more memory modules, one or more programmable hardware or application-specific hardware, and / or several further electronic elements.

[0069] For example, as shown in Figure 13 for BS290, circuit 280 may include a processing circuit 288 and a memory circuit 285. The processing circuit 288 may be controlled by program code stored in the memory circuit 285. The program code may include functional modules 281, 282, and 283 that configure the processing circuit 288 to perform the functions of the BS described above. Specifically, the reference determination module 281 is configured to determine a first information element that identifies the setting parameters of the first satellite and to include it in the system information, and the difference determination module 282 is configured to determine a second information element and to include it in the system information. The transceiver control module 283 controls the transceiver 260 via interface 270 to transmit system information on resources where transmission is scheduled. For example, the transceiver control module 283 outputs the system information to be transmitted to the transceiver 260. The memory circuit 285 may include further modules that realize further functions of BS290.

[0070] For example, as shown in Figure 13 for UE210, circuit 220 may include a processing circuit 228 and a memory circuit 225. The processing circuit 228 may be controlled by program code stored in the memory circuit 225. The program code may include function modules 221, 222, and 223 that configure the processing circuit 228 to perform the functions of the UE described above. Specifically, the reference acquisition module 221 configures the processing circuit to acquire a first information element from system information that identifies the setting parameters of the first satellite, and the difference acquisition module 222 acquires a second information element from system information and determines the settings of the second satellite accordingly. The transceiver control module 223 controls the transceiver 240 via interface 230 to receive system information on resources where transmission is scheduled. For example, the transceiver control module 223 receives a received signal containing system information from the transceiver 240. The memory circuit 225 may include further modules that realize further functions of UE210.

[0071] The memory circuit may be located on the same chip as the processing circuit, or it may be integrated into one or more chips separately from the processing circuit.

[0072] Once one or more configuration parameters for the second satellite are determined from the system information, these configuration parameters may be used by the UE to determine whether or not to perform a handover to a specific adjacent cell, such as a cell operated (irradiated) by the second satellite.

[0073] The following describes some exemplary embodiments of the above signaling parameters for one satellite (second satellite) to refer to another satellite (first satellite).

[0074] Signaling with respect to the reference satellite may be performed by having a second information element identify the difference between the setting parameters of the first satellite and the setting parameters of the second satellite.

[0075] Signaling overhead can potentially be reduced by signaling the differences rather than the entire configuration of the second satellite. For example, parameters with a zero difference (identical in both the first and second satellites) do not need to be included in the second satellite's configuration IE. Instead, a flag indicating the absence of a particular parameter may be included in the system information (e.g., the container IE that communicates the second satellite's configuration). This flag corresponds to the concept that a particular parameter is the same as the corresponding parameter in the first (reference) satellite. Other IE structures are also possible. For example, the IE and fields to be included in the system information may be determined depending on whether the second satellite is in the same orbit as the first satellite (which may be indicated as a flag field). Furthermore, signaling reduction can be achieved if the difference field has a smaller range of values ​​than the range of values ​​in the full field.

[0076] <Signaling the position of a target satellite in the same orbit as a reference satellite> Signaling ephemeris data from satellites in the same orbit can be highly redundant, especially when the ephemeris data is signaled by orbital data, as described above.

[0077] Figure 14 shows a scenario in which the first (reference) satellite 310 and the second (target) satellite 320 share the same orbit 300 around the Earth 390 centered at the geocenter 350. By sharing orbit 300, the only difference in position between the first satellite 310 and the second satellite 320 is an angle of 370.

[0078] Therefore, if the first satellite and the second satellite share the same orbit, the setting parameters for identifying the position of the second satellite may be signaled in the form of a difference. Specifically, the second information element includes the difference in angle between the first satellite and the second satellite with the geocenter as the origin.

[0079] In other words, the distance between a reference satellite 310 and another satellite 320 in the same orbit can be efficiently expressed as an angle 370 anchored to the geocenter 350. Such a field is exemplified as satToSatAngle-r18. The units and ranges for signaling such an angle 370 in satToSatAngle-r18 may be the same as those for the meanAnomaly-r17 field.

[0080] The meanAnomaly-r17 field is an integer with values ​​ranging from 0 to 268435455, and is mapped to angle values ​​from 0 to 2π.

[0081] In Figure 14, satellites 310 and 320 are shown as adjacent satellites. However, this is not required. One reference satellite is used per orbit, and the positions of other satellites in the same orbit may be identified by angle 370. The reference satellite may be a serving satellite. In actual implementations, the system information provided by a serving satellite is likely to include only satellites in the vicinity of the serving cell, i.e., adjacent satellites. However, this disclosure is not limited to such scenarios, and signaling may also be applied to satellites that are not immediately adjacent to a serving satellite or reference satellite.

[0082] Specifically, differential signaling can be particularly efficient when all satellites in the same orbit are equally spaced. An example of such a distribution at present is the Starlink satellite network, at least in some regions.

[0083] Signaling of satellites in the same orbit with an angular difference of 370 degrees may be sufficient as the sole parameter for the orbital information. Furthermore, by making further assumptions about the position of the reference satellite, the range of values ​​for the satToSatAngle parameter can be narrowed.

[0084] <Signaling of a target satellite in an orbit different from the reference satellite's orbit> For satellites in different orbits, signaling redundancy can be further reduced by indicating a target orbit relative to the reference orbit. An example of this is shown in Figure 15.

[0085] Figure 15 shows two orbits, namely orbit A410 and orbit B420, which are shown in Figure 15 as adjacent, substantially parallel orbits. In this example, orbit A410 is the reference orbit and orbit B420 is the target orbit (described in relation to the reference orbit). Both orbits A and B are orbits around Earth 490. If the orbits are “quasi-parallel” or substantially parallel within a coverage area spanning several adjacent satellite cells, the position of the first (target) orbit A410 may be indicated relative to the second (reference) orbit B420 by the interorbital angle 470. Thus, instead of signaling all five parameters that define the orbits in the above Orbital sequence (semi-major axis, eccentricity, inclination, longitude, and perigee), only one parameter, namely the interorbital angle, may be signaled.

[0086] Specifically, a UE receiving system information may receive a second field that includes the difference in angle between a first orbit 410 and a second orbit 420, with the geocenter 450 as the origin. This is particularly suitable when the first satellite is in a first orbit and the second satellite is in a second orbit that is different from and parallel to the first orbit, and the specifications of orbit 420 are part of determining the position of the second satellite.

[0087] BS transmits the corresponding second field, which may be illustratively referred to here as orbitToOrbitAngle or orbitToOrbitAngle-r18. The distance orbitToOrbitAngle between the reference orbit 410 and the target orbit 420, represented by an angle 470 with the geocenter 450 as the anchor point, may have the same units and range as meanAnomaly-r17 described above.

[0088] Such signaling may be particularly suitable for target orbits belonging to the same network (but not limited to these), because the system has complete control and knowledge of the orbit in that case. The reference orbit 410 and the target orbit 420 are not necessarily adjacent.

[0089] The signaling at an interorbital angle of 470 indicates the relative positions of orbits 410 and 420. Nevertheless, there are cases where signaling the position of the target satellite within the target orbit 420 is desirable. As mentioned above, the position of the target satellite may be determined relative to a reference satellite in the same orbit 420. Alternatively, as shown in the following example, the position of the target satellite may be determined relative to a reference satellite in reference orbit 410.

[0090] Here, "parallel," "substantially parallel," and "quasi-parallel" mean that the orbits can be considered parallel in the area covered by at least the cells operated by the reference satellite and the cells operated by the target satellite, i.e., in the area where the UE is currently located and / or moving to receive system information. The entirety of orbits (full circle / ellipse) 410 and 420 do not need to be parallel to each other.

[0091] <Signaling of the phase difference between a target satellite and a reference satellite in different orbits> Figure 16 shows the four satellites 510, 520, 530, and 540. Satellites 510 and 530 are located in the first orbit 501 (also known as orbit A or the reference orbit), and satellites 520 and 540 are located in the second orbit 502 (also known as orbit B, the target orbit, or the adjacent orbit) around the Earth 590. Figure 16 shows the phase shifts 560, 570, and 580 between the adjacent satellites 510, 520, and 540 in adjacent orbit B502 and the reference satellite 530 in reference orbit A501.

[0092] For example, it can be seen that the first (reference) satellite 530 is in the first orbit 501, and the second (target) satellite 520 is in the second orbit 502 which is substantially parallel to the first orbit 501, at least within the coverage of the first and second satellites. In this example, the second information element for identifying the position of the second satellite 520 includes a phase difference 570 between the first satellite 530 in the first orbit 501 and the position 525 corresponding to the orthogonal projection of the position of the second satellite 520 in the second orbit 502 onto the first orbit 501. This corresponds to the case where the second information element for identifying the position of the second satellite 520 includes a phase difference (the same as 570 above if the two orbits A and B are parallel) between the second satellite 520 in the second orbit 502 and the position 535 obtained by orthogonally projecting the position of the first satellite 530 in the first orbit 501 onto the second orbit 502.

[0093] In this specification, when referring to a position obtained by orthogonally projecting the satellite position onto another orbit, it means the position on the other orbit that is the shortest distance from the satellite position.

[0094] As shown in Figure 16, the phase difference (phase shift) 580 between the reference satellite 530 and other adjacent satellites 540 may be signaled in the same way as the phase difference (phase shift) 570 between the reference satellite 530 and adjacent satellite 520 described above. The phase difference 560 between the reference satellite 530 and other satellites 510 in the same orbit 501 may be signaled by the inter-satellite angle, as described above with reference to Figure 14.

[0095] In summary, the phase shift of satellites 520 and 540 in adjacent orbit 502 may be signaled relative to reference satellite 530 in reference orbit 501, that is, it may be expressed as an angle (570, 580) with geocenter 550 as the anchor point. The corresponding field may be exemplaryly called phaseShiftAngle-r18, or more generally, phaseShiftAngle. phaseShiftAngle may have the same units and range as the meanAnomaly-r17 field described above.

[0096] If the phase shift between the reference satellite 530 and all adjacent satellites 520, 540 (or both adjacent orbits) in adjacent orbits is constant, a single notification of the phase difference may suffice.

[0097] The following is an example syntax for ephemeris orbit data notified to a target satellite, based on a reference satellite (i.e., a serving satellite or other determined reference). [Table 4] Specifically, EphemerisDeltaInfo represents the second IE. The second IE constructs an alternative means of providing IE EphemerisInfo to adjacent satellites. Note that this example is illustrative only. The fields satToSatAngle, orbitToOrbitAngle, and phaseShiftAngle are optional. For example, if only satToSatAngle is signaled (and orbitToOrbitAngle and phaseShiftAngle are not signaled), it may indicate that the adjacent satellite is in the same orbit as the reference satellite. If orbitToOrbitAngle and phaseShiftAngle are signaled, the adjacent satellite may be in a different orbit than the reference satellite, and satToSatAngle may not be necessary.

[0098] Within the same orbit, the angle between a reference satellite and an adjacent satellite (with the geocenter as the anchor for this angle representation) may be signaled as satToSatAngle-r18. For satellites in different orbits, the angle between a reference orbit (the orbit in which the reference satellite is located) and an adjacent orbit may be indicated as orbitToOrbitAngle-r18, and the phase shift between the reference satellite in the reference orbit and the adjacent satellite in the adjacent orbit may be signaled as phaseShiftAngle-r18.

[0099] <Types of signaling between satellites> In the previous embodiment, one or more parameters that identify the position of the second satellite were signaled, in particular, by differences, with respect to the corresponding parameters of the first satellite. However, the present disclosure is not limited to signaling differences. Since various parameters of the second satellite may be identical to those of the first satellite, it may be advantageous to signal the identity of the parameters.

[0100] For example, the second information element includes an indication that the configuration parameters of the first satellite are identical to those of the second satellite. This indication may be a Boolean field, sometimes called a flag. Because Boolean fields have a binary value range, they can signal more efficiently than values ​​with a larger value range, such as the angle difference mentioned above in relation to the meanAnomaly-r17 field, which is an integer in the range of 0 to 268435455. For example, signaling whether the parameters of the second satellite are identical to those of the first satellite can be done with one bit.

[0101] By specifying the angles mentioned above (e.g., inter-satellite angle 370, inter-orbital angle 470, and / or phase difference 570 or 580), the remaining parameters, such as the velocity of the second satellite (assuming it is the same as the velocity of the first satellite), can be derived by the UE. For example, satellite velocity in orbit is usually given as the square root of gravitational constant × Earth's mass / orbital radius (measured from the geocenter). Therefore, as long as the orbits are at the same altitude, the satellite velocity will be the same in the reference orbit and adjacent orbits.

[0102] In some non-limiting exemplary embodiments of identity signaling, the instructions specify at least one of the following:

[0103] a) The angle between two adjacent satellites in the same orbit is the same as the angle between two adjacent satellites in the same orbit.

[0104] b) The angle between the two adjacent orbits is the same as the angle between the first orbit of the first satellite and the adjacent orbit of the second satellite.

[0105] c) The phase shift (phase difference) between two satellites in a single orbit is twice the phase shift (phase difference) between the first satellite in an adjacent orbit to that orbit and the satellite closest to the first satellite in that orbit.

[0106] For example, a) may be useful if the satellites are evenly distributed around the Earth, at least in terms of the area covered by the serving satellite and its adjacent satellites, or by satellites operating adjacent cells of the cells operated by the serving satellite. Furthermore, the angle difference (e.g., satToSatAngle or phaseShiftAngle above) does not need to be signaled to each adjacent (or generally target) satellite, but only to one of the adjacent satellites. For the remaining adjacent satellites, identity indication a) may be provided. This is shown in Figure 17. Specifically, the angle 625 between satellites 620 and 630 in the same orbit 600 is the same as the angle 615 between the reference satellite (in this example, satellite 610) and satellite 620. For this reason, a satToSatAngle parameter that refers to the reference satellite 610 and signals angle 615 may be signaled to satellite 620. In addition, an identity indication indicating that angle 625 is identical to angle 615 may be signaled to satellite 630. For example, the reference satellite 610 may be a serving satellite, and satellite 620 may be determined by default as the first satellite in the list of neighboring satellites. Further examples are possible. For example, a satellite other than the first in the list of neighboring satellites may be selected as the default, and the reference satellite 610 and / or satellite 620 may be configurable.

[0107] Similarly, in the case of identity b), the inter-orbit angle 470, as described with reference to Figure 15, may be signaled for one adjacent orbit. Then, identity to the inter-orbit angle 470 may be indicated for further adjacent (quasi)parallel orbit pairs.

[0108] Regarding c), as can be seen in Figure 16, identity may indicate that the phase shift (phase difference) between the two satellites 520 and 540 in one orbit 502 is twice the phase shift (phase difference) 570 between the first satellite 510 in the adjacent orbit 501 of one orbit 502 and the satellite 520 closest to the first satellite in one orbit 502.

[0109] Furthermore, as mentioned above with reference to Figure 16, the phase shift signaling may imply a certain degree of parallelism between the satellite configurations in the different orbits where the first and second satellites are located.

[0110] As described above, the identity indicator may be a binary flag (a Boolean of the corresponding field). However, this disclosure is not limited to such signaling. The identity indicator may be a predetermined value within the value range of the second information element (e.g., the first or last value in the range), or a predetermined value within the value range of the first information element. The predetermined value may be, for example, 0×FFFFFFFF at the end of the value range.

[0111] Examples a), b), and c) above illustrate signaling of identity for various difference parameters. However, the disclosure is not limited thereto. In some systems, satellites may be distributed uniformly around the Earth or according to a predetermined pattern. In such cases, it may be more efficient to indicate the characteristics of the satellite distribution pattern. For example, in one embodiment of signaling, a second information element indicates that satellites are uniformly distributed around the orbit of a first satellite. Alternatively, the second information element may indicate that the satellite orbits are uniformly distributed around the orbit of the first satellite. Alternatively, the second information element may indicate that all satellites in the network are at the same velocity.

[0112] In addition to notifying patterns, patterns may be further quantified. For example, system information may notify that a certain number of satellites are distributed at equal intervals on a certain orbit. For example, 18 satellites are distributed at equal intervals on orbit A, with an angle between them of, say, 20°. In other words, the system information may identify the number of satellites relative to a serving satellite or reference satellite that share a certain pattern, such as an equally spaced distribution where the angles between adjacent satellites are the same. Then, for the same orbit, the angle between each pair of adjacent satellites may be signaled once. Therefore, signaling for the positions of individual adjacent satellites on the same orbit is completely unnecessary.

[0113] <Signaling of satellite operating status> In a satellite network, some satellites may be orbiting in their expected positions but not operational. In particular, when satellite patterns are signaled (see the exemplary embodiments of signaling described above), the UE can expect all evenly spaced satellites, or generally all satellites described by the pattern, to be operational. To enable the indication of operational satellites, system information includes indications of the operational status of multiple satellites, including at least one of a first satellite and a second satellite.

[0114] In particular, the operational status indication is a bit sequence (which may be called a bitmap or bit image register) in which each bit indicates whether or not each of the multiple satellites is operational.

[0115] The bit image register may indicate the reference satellite (e.g., the satellite irradiating the serving cell) with the most significant bit. When it becomes possible to transmit system information, it may be considered to be operating at that time, and the reference satellite may not be shown at all in the bitmap. For example, in the case of 18 satellites in the above orbit, 16 of them are in operation and 2 are currently malfunctioning. In the binary representation (bitmap), it may be like 11 1101 1111 1011 1111. Zero corresponds to a non-operating satellite, and 1 corresponds to an operating satellite. The first bit (transmitting a value of 1) corresponds to the serving cell, and the remaining 17 satellites are satellites on the same orbit that are sequentially listed in the direction of the satellite speed in the orbit. However, this direction is an example, and the reverse direction may be selected.

[0116] <Examples in RRC Signaling> An example of the second IE EphemerisDeltaInfo-r18 including some of the above-described elements (parameters) is shown below. EphemerisDeltaInfo-r18 refers to the IE EphemerisInfo-r17 of the reference (first) satellite.

Table 5

[0117] The parameter noOfSatsInOrbit-r18 identifies the total number of satellites in the orbit specified by OrbitId-r18.

[0118] The parameter identityFlag-r18, when set to "1", indicates the following.

[0119] a) The settings for orbitId-r18, noOfSatsInOrbit-r18, operationalStatus-r18, and satToSatPhaseShiftAngle-r18 are the same for all satellites in the same orbit.

[0120] b) The settings for all elements except identityFlag-r18 are identical for all satellites in adjacent orbits.

[0121] c) The settings for orbitId-r18, noOfSatsInOrbit-r18, satToSatPhaseShiftAngle-r18, and orbitToOrbitAngle-r18 are identical for all satellites in multiple adjacent orbits.

[0122] The parameter `operationalStatus-r18` identifies the operational status of all satellites in orbit identified by `orbitId-r18`. The given value is interpreted as a bit image register (BIR). Each bit, when set to "1", indicates an operational satellite, and when set to "0", indicates a non-operational satellite. The most significant bit (msb) indicates the reference satellite, the next bit to its right indicates the status of the first neighboring satellite, and so on.

[0123] The parameter satToSatPhaseShiftAngle-r18 indicates the angle between the adjacent satellite and the reference satellite in the case of identical orbits. The geocenter is the anchor point for this angle. In the case of adjacent orbits, this element indicates the phase difference between the reference satellite in the reference orbit and the adjacent satellite in the adjacent orbit. With the geocenter as the anchor point, this angle notification points to the orthogonal projection of the reference satellite onto the specified adjacent orbit and the position of the described adjacent satellite.

[0124] The parameter orbitToOrbitAngle-r18, in the case of adjacent orbits, indicates the angle between the reference orbit and the adjacent orbit described, with the geocenter as the anchor point.

[0125] The parameter AltitudeDiff-r18 indicates the altitude difference between the reference orbit and the adjacent orbit described herein, in the case of adjacent orbits.

[0126] The parameter OrbitAngleDiff-r18 indicates the deviation from the parallelism between the reference orbit and the adjacent orbit in the case of adjacent orbits.

[0127] The following shows some exemplary uses of EphemerisDeltaInfo-r18 parameters. In the first example, when the first and second satellites are in the same orbit, EphemerisDeltaInfo-r18 may have only the following elements: [Table 6] Note that not all of the above parameters included in EphemerisDeltaInfo-r18 in the first example are necessary. For example, if identityFlag-18 is set to 1 and the serving satellite or other reference satellite has been previously signaled, additional parameters may not be required. Therefore, these can be omitted from EphemerisDeltaInfo-r18, further reducing signaling overhead.

[0128] The second example shows a possible use of EphemerisDeltaInfo-r18 in the case of a single adjacent orbit. [Table 7] In this case, all parameters may be used, or some parameters may be used (for example, if the identity flag is set to 1).

[0129] The third example shows a possible use of EphemerisDeltaInfo-r18 in the case of multiple adjacent orbitals. [Table 8]

[0130] <Example Method> Methods are provided that can be performed by terminals and network nodes (access nodes, base stations) in response to the operations described as being performed by UE and BS devices. These methods are shown in Figures 18 and 19.

[0131] Specifically, Figure 18 shows a method for receiving system information relating to satellite configuration. This method may be performed, for example, by a terminal in a network including satellite cells. The method includes a step 1810 of receiving system information. Furthermore, the method includes a step 1820 of determining a first information element from the system information that identifies the configuration parameters of a first satellite, and a step 1830 of determining a second information element from the system information, and with reference to the configuration parameters of the first satellite, that identifies the configuration parameters of a second satellite different from those of the first satellite.

[0132] Figure 19 shows a method for transmitting system information regarding satellite configuration. This method may be performed, for example, at a base station or similar access node, or network node. This method includes generating system information (1910-1930) and transmitting the generated system information (1940). Specifically, generating system information includes the following steps.

[0133] • Include a first information element in the system information that identifies the configuration parameters of the first satellite (1930).

[0134] • Referencing the configuration parameters of the first satellite, determine a second information element that identifies configuration parameters for the second satellite that are different from those of the first satellite (1920).

[0135] • Include a second information element in the system information (1930).

[0136] Furthermore, this method may include determining a first information element (1910). Step 1910 can be performed at any stage prior to steps 1920 and 1930, but does not necessarily have to be part of the method described herein.

[0137] Figure 20 shows an exemplary method performed by the UE. Specifically, the UE monitors the system information in SIB19 (System Information Block, which transmits information about the non-terrestrial network) (210). If the SIB19 is received (Yes in step 215), in step 220, the UE extracts and stores information about the serving satellite (generally a serving cell or reference cell) and reference orbit from the SIB19. If it is not received (No in step 215), the method returns to step 210. In step 230, the method checks whether information about neighboring cells is provided in the SIB19. If it is not provided (No in step 230), the method returns to monitoring the system information in step 210. If it is provided, the method continues by distinguishing whether the received and stored information about neighboring cells (satellites) is full ephemeris information (240) or ephemeris information about other (reference) cells (see step 250).

[0138] If full ephemeris information is provided (240), in step 245 the non-redundant portion of the information is extracted, the extracted information is converted to the UE storage / database format (255) and stored in step 295.

[0139] If delta ephemeris information is provided (250), the information is converted to the UE storage / database format (260). Then, in step 270, the reference information is read from the UE database (storage). In step 280, adjacent satellite data is calculated based on the already stored reference data and the received delta information. Finally, the calculated adjacent satellite data is stored in the UE database (storage) (290).

[0140] <Implementation of this disclosure through hardware and software> This disclosure can be implemented as software, hardware, or software in conjunction with hardware. Each functional block used in the description of the above embodiments may be implemented partially or entirely as an integrated circuit (LSI), and each process described in the above embodiments may be controlled partially or entirely by a single LSI or a combination of LSIs. An LSI may consist of individual chips, or it may consist of a single chip that includes some or all of the functional blocks. An LSI may have data inputs and outputs. Depending on the degree of integration, LSIs may be referred to as ICs, system LSIs, super LSIs, or ultra LSIs. The method of integrated circuit implementation is not limited to LSIs, and may also be implemented with dedicated circuits, general-purpose processors, or dedicated processors. Furthermore, an FPGA (Field Programmable Gate Array) that can be programmed after LSI manufacturing, or a reconfigurable processor that can reconfigure the connections and settings of circuit cells inside the LSI, may be used. This disclosure may be implemented as digital processing or analog processing. Furthermore, if advancements in semiconductor technology or related technologies lead to the emergence of integrated circuit technologies that replace LSIs, then naturally, these technologies can be used to integrate functional blocks. The application of biotechnology, for example, is a possible possibility.

[0141] This disclosure is applicable to all types of devices, systems, and equipment with communication capabilities (collectively referred to as communication equipment).

[0142] The communication device may include a wireless transceiver (transmitting / receiving unit) and a processing / control circuit. The wireless transceiver may include a receiving unit and a transmitting unit, or both as functions. The wireless transceiver (transmitting unit, receiving unit) may include an RF (Radio Frequency) module and one or more antennas. The RF module may include an amplifier, an RF modulator / demodulator, or something similar.

[0143] Non-exclusive examples of communication devices include telephones (mobile phones, smartphones, etc.), tablets, personal computers (PCs) (laptops, desktops, netbooks, etc.), cameras (digital still / video cameras, etc.), digital players (digital audio / video players, etc.), wearable devices (wearable cameras, smartwatches, tracking devices, etc.), game consoles, digital book readers, telehealth / telemedicine devices, vehicles or mobile transport with communication capabilities (cars, airplanes, ships, etc.), and combinations of the above-mentioned devices.

[0144] Communication devices are not limited to portable or movable devices, but also include all kinds of non-portable or fixed devices, devices, and systems, such as smart home devices (appliances, lighting equipment, smart meters or measuring instruments, control panels, etc.), vending machines, and any other "things" that may exist on an IoT (Internet of Things) network.

[0145] Communication includes data communication via cellular systems, wireless LAN systems, and communication satellite systems, as well as data communication using combinations of these.

[0146] Furthermore, the communication device also includes devices such as controllers and sensors that are connected to or linked to a communication device that performs the communication functions described in this disclosure. For example, this includes controllers and sensors that generate control signals and data signals used by the communication device that performs the communication functions of the communication device.

[0147] Furthermore, communication equipment includes infrastructure facilities such as base stations, access points, and any other devices, devices, and systems that communicate with or control the aforementioned non-limited types of equipment.

[0148] Furthermore, various embodiments can also be implemented by software modules. These software modules may be executed by a processor or directly in hardware. Combinations of software modules and hardware implementations are also possible. The software modules may be stored in any type of computer-readable storage medium. In particular, other implementations provide non-temporary computer-readable recording media. When executed by one or more processors, the recording media stores a program that causes one or more processors to perform steps of the method according to this disclosure.

[0149] As an unrestricted example, such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage devices, magnetic disk storage devices or other magnetic storage devices, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and can be accessed by a computer. Any connection is also referred to as computer-readable media, as appropriate. For example, if instructions are transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of media. However, it should be understood that computer-readable storage media and data storage media do not include connections, carriers, signals, or other temporary media, but instead refer to non-temporary tangible storage media. The discs used herein include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy discs, and Blu-ray discs. "Disk" typically refers to a medium that reproduces data magnetically, while "disc" refers to a medium that reproduces data optically using a laser. Any combination of the above should also be included within the scope of computer-readable media.

[0150] Furthermore, it should be noted that individual features of several different embodiments can be the subject of other embodiments, individually or in any combination. Those skilled in the art will understand that various changes and / or modifications can be made to the specific embodiments of this disclosure without departing from the broadly defined concept or scope of the invention. Therefore, the embodiments described herein are illustrative in all respects and are not intended to limit the invention.

[0151] <Summary of Embodiments> According to the first embodiment, a user device (UE) is provided, the UE comprising: a transmitting and receiving unit that receives system information when in operation; and a circuit that, when in operation, determines a first information element that identifies the setting parameters of a first satellite from the system information, and determines a second information element that identifies the setting parameters of a second satellite different from the first satellite from the system information and by referring to the setting parameters of the first satellite.

[0152] According to the second embodiment, in addition to the first embodiment, the second information element identifies the difference between the setting parameters of the first satellite and the setting parameters of the second satellite.

[0153] According to the third aspect, in addition to the second aspect, the first satellite and the second satellite share the same orbit, the setting parameter is the satellite position, and the second information element includes the angular difference between the first satellite and the second satellite with respect to the Earth's center.

[0154] According to the fourth aspect, in addition to the second or third aspect, the first satellite is in a first orbit, the second satellite is in a second orbit which is different from the first orbit and parallel to the second orbit, the setting parameter is the satellite position, and the second information element includes the angular difference between the first orbit and the second orbit originating from the geocenter.

[0155] According to the fifth aspect, in addition to any one aspect of the second to fourth aspects, the first satellite is in a first orbit, the second satellite is in a second orbit parallel to the first orbit, the setting parameter is the satellite position, and the second information element includes the phase difference between the first satellite in the first orbit and the position obtained by orthogonally projecting the position of the second satellite in the second orbit onto the first orbit, or the phase difference between the second satellite in the second orbit and the position obtained by orthogonally projecting the position of the first satellite in the first orbit onto the second orbit.

[0156] According to the sixth aspect, in addition to any one aspect of the first to fifth aspects, the second information element includes an instruction that identifies the setting parameter of the first satellite as being the same as the setting parameter of the second satellite.

[0157] According to the seventh aspect, in addition to the sixth aspect, the instruction specifies at least one of the following: the angle between two adjacent satellites in the same orbit is the same as the angle between the adjacent first satellite and the second satellite in the same orbit; the angle between two adjacent orbits is the same as the angle between the first orbit of the first satellite and the adjacent orbit of the second satellite; and the phase shift between two satellites in one orbit is twice the phase shift between the first satellite in an adjacent orbit of the one orbit and the satellite in the one orbit closest to the first satellite.

[0158] According to the eighth aspect, in addition to the sixth aspect, the instruction is a binary flag, a predetermined value from the value range of the second information element, or a predetermined value from the value range of the first information element.

[0159] According to the ninth aspect, in addition to the first or third aspect, the second information element indicates that the satellites are evenly distributed in the orbit of the first satellite.

[0160] According to the tenth aspect, in addition to any one aspect of the first to ninth aspects, the system information includes an indication of the operating status of a plurality of satellites, including at least one of the first satellite and the second satellite.

[0161] According to the eleventh aspect, in addition to the tenth aspect, the indication of the operating state is a bit sequence in which each bit indicates whether or not the satellite is operating for each of the plurality of satellites.

[0162] According to the twelfth aspect, a base station (BS) is provided, the base station (BS) comprising: a transceiver unit that transmits system information when in operation; and a circuit that generates the system information when in operation, the generation comprising: a step of including a first information element that identifies the setting parameters of a first satellite in the system information; a step of determining a second information element that identifies the setting parameters of a second satellite different from the first satellite, with reference to the setting parameters of the first satellite; and a step of including the second information element in the system information.

[0163] Furthermore, the second through eleventh aspects also apply to base stations in order to define further signaling that is generated and transmitted by the base station and subsequently received by the UE described above.

[0164] According to the 13th aspect, a method is provided for receiving system information relating to satellite configuration, the method comprising: receiving system information; determining a first information element from the system information that identifies configuration parameters of a first satellite; and determining a second information element from the system information and with reference to the configuration parameters of the first satellite that identifies configuration parameters of a second satellite different from the first satellite.

[0165] A method for transmitting system information relating to satellite configuration is provided, the method for transmitting system information relating to satellite configuration, comprising the steps of generating the system information, the steps of including in the system information a first information element that identifies configuration parameters of a first satellite, determining a second information element that identifies configuration parameters of a second satellite different from the first satellite by referring to the configuration parameters of the first satellite, and including the second information element in the system information, and transmitting the system information.

[0166] Furthermore, the second through eleventh embodiments also apply to the above-described methods in order to define further signaling that is generated and transmitted by the base station method and subsequently received and used by the UE method described above.

[0167] According to the 15th aspect, program code is provided, which is stored in a computer-readable non-transient medium and includes code instructions that, when executed by one or more processors, cause the one or more processors to perform the steps described in any of the above-described methods.

Claims

1. During operation, a transceiver unit receives system information, During operation, From the aforementioned system information, a first information element is determined to identify the setting parameters of the first satellite. The system includes a circuit that determines a second information element that identifies setting parameters for a second satellite different from those of the first satellite, based on the system information and by referring to the setting parameters of the first satellite. User equipment (UE).

2. The second information element identifies the difference between the setting parameters of the first satellite and the setting parameters of the second satellite. The UE according to claim 1.

3. The first satellite and the second satellite share the same orbit, The aforementioned setting parameter is the satellite position, The second information element includes the angular difference between the first satellite and the second satellite, with respect to the Earth's center. The UE according to claim 2.

4. The first satellite is in a first orbit, and the second satellite is in a second orbit that is different from the first orbit and parallel to the first orbit. The aforementioned setting parameter is the satellite position, The second information element includes the angular difference between the first orbit and the second orbit, with respect to the geocenter. The UE according to claim 2.

5. The first satellite is in a first orbit, and the second satellite is in a second orbit parallel to the first orbit. The aforementioned setting parameter is the satellite position, The second information element described above is, The phase difference between the position of the first satellite in the first orbit and the position obtained by orthogonally projecting the position of the second satellite in the second orbit onto the first orbit, or The phase difference between the second satellite in the second orbit and the position obtained by orthogonally projecting the position of the first satellite in the first orbit onto the second orbit includes, The UE according to claim 2.

6. The second information element includes an instruction that identifies the setting parameters of the first satellite as being the same as the setting parameters of the second satellite. The UE according to claim 1.

7. The above instructions are, The angle between two adjacent satellites in the same orbit is the same as the angle between the adjacent first satellite and the second satellite in the same orbit, The angle between the two adjacent orbits is the same as the angle between the first orbit of the first satellite and the adjacent orbit of the second satellite. Specify at least one of the following: the phase shift between two satellites in one orbit is twice the phase shift between the first satellite in an adjacent orbit to the first satellite and the satellite in the first orbit closest to the first satellite. The UE according to claim 6.

8. The above instructions are, Binary flag, or A predetermined value from the value range of the second information element, or A predetermined value within the value range of the first information element, The UE according to claim 6.

9. The second information element indicates that satellites are evenly distributed in the orbit of the first satellite. The UE according to claim 1.

10. The system information includes an indication of the operating status of a plurality of satellites, including at least one of the first satellite and the second satellite. The UE according to claim 1.

11. The aforementioned indication of the operating state is a bit sequence in which each bit indicates whether or not the satellite is operating for each of the plurality of satellites. The UE according to claim 10.

12. During operation, a transmitting and receiving unit transmits system information, A base station (BS) comprising a circuit that generates the aforementioned system information during operation, The aforementioned generation is The steps include including a first information element that identifies the setting parameters of the first satellite in the system information, The steps include determining a second information element that identifies setting parameters for a second satellite different from those of the first satellite, by referring to the setting parameters of the first satellite, The step of including the second information element in the system information, BS.

13. A method for receiving system information regarding satellite settings, The steps include receiving the aforementioned system information, The steps include determining a first information element that identifies the setting parameters of the first satellite from the aforementioned system information, The system includes the step of determining a second information element that identifies setting parameters for a second satellite that are different from those of the first satellite, using the system information and referring to the setting parameters of the first satellite. method.

14. A method for transmitting system information relating to satellite settings, The step of generating the aforementioned system information, The system information includes a first information element that identifies the setting parameters of the first satellite, The process involves determining a second information element that identifies setting parameters for a second satellite that are different from those of the first satellite, by referring to the setting parameters of the first satellite, A step including including the second information element in the system information, The step of transmitting the aforementioned system information includes method.

15. A code instruction which, when executed by one or more processors, causes one or more processors to perform the steps described in claim 13 or 14, A computer program stored on a non-transient medium that is readable by a computer.

16. An integrated circuit that controls the processing of user equipment (UE) during operation, wherein the processing is: The steps include receiving system information, The steps include determining a first information element that identifies the setting parameters of the first satellite from the aforementioned system information, The system includes the step of determining a second information element that identifies setting parameters for a second satellite that are different from those of the first satellite, using the system information and referring to the setting parameters of the first satellite. Integrated circuit.

17. An integrated circuit that controls the processing of a base station (BS) during operation, wherein the processing is: A step of generating system information, The system information includes a first information element that identifies the setting parameters of the first satellite, The process involves determining a second information element that identifies setting parameters for a second satellite that are different from those of the first satellite, by referring to the setting parameters of the first satellite, A step including including the second information element in the system information, The step of transmitting the aforementioned system information is included, Integrated circuit.

Images