Processing method, user equipment, and base station

Abstract

SOLUTION: The user equipment (UE) performs measurements to calculate the Doppler shift and transmits the Doppler shift to the satellite. The satellite transmits the Doppler shift correction to the UE. The UE applies a Doppler shift correction to the uplink transmission.EFFECT: Doppler shift measurement and correction between a UE and a satellite in a non-terrestrial network (NTN) can be performed.SELECTED DRAWING: Figure 16

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 63 / 182,565, filed April 30, 2021 (the "Provisional Application"), the contents of which are incorporated herein by reference. [Background technology]

[0002] This invention is directed to 5G, the fifth generation mobile network. It is the new global wireless standard following 1G, 2G, 3G, and 4G networks. 5G enables networks designed to connect machines, objects, and devices.

[0003] The present invention relates to an apparatus and method for Doppler shift measurement and correction between user equipment (UE) and a satellite in a non-terrestrial network (NTN), more particularly. In one embodiment, the UE performs measurements to calculate the Doppler shift and transmits the Doppler shift to the satellite. In another embodiment, the satellite measures the Doppler shift of each UE and transmits the Doppler shift to each UE. The Doppler shift correction is applied to uplink transmission signals. Summary of the Invention

[0004] In one embodiment, the present invention provides a method of Doppler shift calculation for use by a user equipment (UE). The method includes measuring a downlink (DL) signal transmitted from a satellite, estimating a Doppler shift from the measurements, transmitting the Doppler shift to the satellite, receiving a message from the satellite including a Doppler shift correction, and applying the Doppler shift correction to an uplink transmission signal. The measuring step includes measuring a downlink sounding reference signal. Preferably, the Doppler shift includes a frequency shift between a first frequency associated with the downlink (DL) signal transmitted from the satellite and a second frequency associated with the DL signal received by the UE due to motion of the user equipment (UE). The estimating Doppler shift includes determining a frequency at which the downlink (DL) signal has a peak. Furthermore, the received message embodies a Doppler shift correction signal.

[0005] In one embodiment, the present invention provides a method for Doppler shift measurement by a satellite, the method including the steps of receiving a message including a measurement report from a user equipment (UE), calculating a Doppler shift correction from the measurement report, applying the Doppler shift correction to a downlink (DL) signal, and transmitting the DL signal to the user equipment (UE), the measurement report including a Doppler shift value that is a difference between a first frequency of the downlink (DL) signal transmitted from the satellite and a second frequency of the DL signal received by the user equipment (UE).

[0006] In one embodiment, the present invention provides a method for Doppler shift calculation by a user equipment (UE), the method comprising the steps of measuring a downlink (DL) signal transmitted from a satellite, estimating a Doppler shift from the measurement, estimating a Doppler shift correction therefor, and applying the Doppler shift correction to an uplink transmitted signal. The measured downlink (DL) signal may be a downlink sounding reference signal. The method includes a step of estimating a Doppler shift between a first frequency associated with a downlink (DL) signal transmitted from a satellite and a second frequency associated with a downlink (DL) signal received by a user equipment (UE) due to motion of the UE. Estimating the Doppler shift includes determining a frequency at which the downlink (DL) signal has a peak. The method can include transmitting an uplink (UL) signal to the satellite.

[0007] The present invention also provides a method of Doppler shift compensation by a user equipment (UE), the method including the steps of receiving a message signal from a satellite, the message signal reflecting a Doppler shift of a signal transmitted from the satellite to the UE, and generating and applying a Doppler shift compensation to an uplink transmission signal based on the Doppler shift, the Doppler shift being the difference between a first frequency of an uplink (UL) signal transmitted from the user equipment (UE) and a second frequency of the UL signal received by the satellite.

[0008] In one embodiment, the present invention provides a method for measuring Doppler shift by a satellite, the method including the steps of measuring uplink (UL) signals transmitted from user equipment (UE), estimating a Doppler shift for each UE from each of the UE's respective measurements, and transmitting the respective Doppler shifts to each of the UEs. Measuring the uplink (UL) signals includes measuring an uplink sounding reference signal. Preferably, the Doppler shift includes a frequency shift between a first frequency associated with the uplink (UL) signals transmitted from the UE and a second frequency associated with each UL signal received by the satellite, due to motion of the user equipment (UE).

[0009] The present invention also provides a user equipment (UE) constructed in accordance with the principles of the present invention, the UE including a transceiver configured to measure a downlink (DL) signal transmitted from a satellite to achieve measurements, transmit the measurements to the satellite, and receive a message signal from the satellite reflecting a Doppler shift correction, and a processor in communication with the transceiver, the processor further configured to estimate a Doppler shift correction from the measurements and apply the Doppler shift correction to an uplink (UL) signal for transmission by the transceiver.

[0010] The present invention also includes a satellite constructed in accordance with the principles of the present invention, the satellite including a transceiver configured to measure uplink (UL) signals received from user equipment (UE) and to transmit message signals to the UEs indicative of the Doppler shift of each UE, and a processor in communication with the transceiver, the processor configured to estimate the Doppler shift from the measured UL signals received from each UE. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 illustrates an example of a mobile communication system in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 2A] FIG. 1 illustrates example radio protocol stacks for the user plane and control plane in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 2B] FIG. 1 illustrates example radio protocol stacks for the user plane and control plane in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 3A] FIG. 1 illustrates an example mapping between logical channels and transport channels in the downlink, uplink, and sidelink in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 3B]FIG. 1 illustrates an example mapping between logical channels and transport channels in the downlink, uplink, and sidelink in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 3C] FIG. 1 illustrates an example mapping between logical channels and transport channels in the downlink, uplink, and sidelink in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 4A] FIG. 1 illustrates example mappings between transport channels and physical channels in the downlink, uplink, and sidelink in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 4B] FIG. 1 illustrates example mappings between transport channels and physical channels in the downlink, uplink, and sidelink in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 4C] FIG. 1 illustrates example mappings between transport channels and physical channels in the downlink, uplink, and sidelink in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 5A] FIG. 1 illustrates an example radio protocol stack for NR sidelink communications in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 5B] FIG. 1 illustrates an example radio protocol stack for NR sidelink communications in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 5C] FIG. 1 illustrates an example radio protocol stack for NR sidelink communications in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 5D] FIG. 1 illustrates an example radio protocol stack for NR sidelink communications in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 6] FIG. 1 illustrates exemplary physical signals in the downlink, uplink, and sidelink in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 7] 1 illustrates an example of radio resource control (RRC) states and transitions between different RRC states in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 8] FIG. 1 illustrates an example frame structure and physical resources in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 9] 1A-1C illustrate example component carrier configurations in different carrier aggregation scenarios in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 10] 1 illustrates exemplary bandwidth portion configurations and switching in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 11] FIG. 1 illustrates an exemplary four-step contention-based and contention-free random access process, in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 12A] FIG. 1 illustrates an example of a non-transparent non-terrestrial wireless network (NTN) in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 12B] FIG. 1 illustrates an example of a transparent non-terrestrial wireless network (NTN) in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 13] FIG. 1 illustrates an example system for Doppler frequency measurement and correction between user equipment and a satellite in accordance with certain aspects of various exemplary embodiments of the present disclosure. [Figure 14] FIG. 1 illustrates exemplary components of a user equipment for transmission and / or reception in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 15]FIG. 1 illustrates exemplary components of a base station for transmission and / or reception in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 16] FIG. 1 is a flow diagram illustrating a first embodiment of a method for Doppler frequency measurement and correction in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 17] FIG. 10 is a flow diagram illustrating a second embodiment of a method for Doppler frequency measurement and correction in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 18A] FIG. 10 is a flow diagram illustrating a second embodiment of a method for Doppler frequency measurement and correction in accordance with some aspects of various exemplary embodiments of the present disclosure. [Figure 18B] FIG. 10 is a flow diagram illustrating a second embodiment of a method for Doppler frequency measurement and correction in accordance with some aspects of various exemplary embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] 1 illustrates an example of a mobile communication system 100 according to some aspects of various exemplary embodiments of the present disclosure. The mobile communication system 100 may be operated by a wireless communication system operator, such as a mobile network operator (MNO), a private network operator, a multi-system operator (MSO), an Internet of Things (IoT) network operator, etc., and may provide services such as voice, data (e.g., wireless Internet access), messaging, vehicular communication services such as vehicle-to-vehicle, vehicle-to-infrastructure, and vehicle-to-everything (V2X) communication services, safety services, mission-critical services, and services in residential, commercial, or industrial environments, such as IoT and Industrial IoT (IIOT).

[0013] The mobile communication system 100 can enable various types of applications with different requirements regarding latency, reliability, throughput, etc. Examples of supported applications include enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC). eMBB can support stable connections with high peak data rates and moderate rates for cell-edge users. URLLC can support applications with stringent requirements regarding latency and reliability, as well as moderate requirements regarding data rates. An exemplary mMTC application includes a network of many IoT devices that are only sporadically active and transmit small data payloads.

[0014] The mobile communication system 100 may include a radio access network (RAN) portion and a core network portion. In the example shown in FIG. 1, a Next Generation RAN (NG-RAN) 105 and a 5G Core Network (5G-CN) 110 are shown as examples of the RAN and core network, respectively. Other examples of the RAN and core network may be implemented without departing from the scope of this disclosure. Other examples of the RAN include an Evolved Universal Terrestrial Radio Access Network (EUTRAN), a Universal Terrestrial Radio Access Network (UTRAN), etc. Other examples of the core network include an Evolved Packet Core (EPC), a UMTS Core Network (UCN), etc. In some examples, the RAN or 5G-CN may be connected to a non-terrestrial network (NTN) via a gateway interface. The RAN implements a radio access technology (RAT) and resides between the user equipment (UE) 125 and the core network. Examples of such RATs include New Radio (NR), Long Term Evolution (LTE), also known as Evolved Universal Terrestrial Radio Access (EUTRA), Universal Mobile Telecommunications System (UMTS), etc. The RAT of the example mobile communication system 100 may be NR. The core network provides communication between the RAN and one or more external networks (e.g., data networks). and is responsible for functions such as mobility management, authentication, session management, bearer setup, and application of different Quality of Service (QoS). The functional layer between the UE 125 and the RAN (e.g., NG-RAN 105) may be referred to as an Access Stratum (AS), and the functional layer between the UE 125 and the core network (e.g., 5G-CN 110) may be referred to as a Non-access Stratum (NAS).

[0015] The UE 125 may include wireless transmission and reception means for communicating with one or more nodes in a RAN, one or more relay nodes, one or more other UEs, etc. Examples of UEs include, but are not limited to, smartphones, tablets, laptops, computers, wireless transmitting and / or receiving units in vehicles, V2X or vehicle-to-vehicle (V2V) devices, wireless sensors, IoT devices, IIOT devices, etc. Other names may be used for the UE, such as mobile station (MS), terminal equipment, terminal node, client device, mobile device, etc.

[0016] The RAN may include nodes (e.g., base stations) for communicating with UEs. For example, the NG-RAN 105 of the mobile communication system 100 may include nodes for communicating with the UE 125. Different names may be used for the RAN nodes depending, for example, on the RAT used for the RAN. A RAN node may be referred to as a Node B (NB) in a RAN using the UMTS RAT. A RAN node may be referred to as an Evolved Node B (eNB) in a RAN using the LTE / EUTRA RAT. In the exemplary example of the mobile communication system 100 of FIG. 1, the node of the NG-RAN 105 may be either a Next Generation Node B (gNB) 115 or a Next Generation Evolved Node B (ng-eNB) 120. In this specification, the terms base station, RAN node, gNB, and ng-eNB may be used interchangeably. The gNB 115 may provide NR user plane and control plane protocol terminations for the UE 125. The ng-eNB 120 may provide E-UTRA user plane and control plane protocol terminations for the UE 125. The interface between the gNB 115 and the UE 125 or between the ng-eNB 120 and the UE 125 may be referred to as a Uu interface. The Uu interface may be established using a user plane protocol stack and a control plane protocol stack. For the Uu interface, the direction from the base station (e.g., the gNB 115 or the ng-eNB 120) to the UE 125 may be referred to as the downlink, and the direction from the UE 125 to the base station (e.g., the gNB 115 or the ng-eNB 120) may be referred to as the uplink.

[0017] The gNB 115 and the ng-eNB 120 may be interconnected using an Xn interface. The Xn interface may include an Xn user plane (Xn-U) interface and an Xn control plane (Xn-C) interface. The transport network layer of the Xn-U interface may be built on Internet Protocol (IP) transport, and GPRS Tunneling Protocol (GTP) may be used on User Datagram Protocol (UDP) / IP to carry user plane protocol data units (PDUs). Xn-U may provide non-guaranteed delivery of user plane PDUs and may support data forwarding and flow control. The transport network layer of the Xn-C interface may be built on Stream Control Transport Protocol (SCTP) over IP. The application layer signaling protocol may be referred to as Xn Application Protocol (XnAP). The SCTP layer may provide guaranteed delivery of application layer messages. At the transport IP layer, point-to-point transmission may be used to deliver signaling PDUs. The Xn-C interface can support Xn interface management, UE mobility management including context transfer and RAN paging, and dual connectivity.

[0018] The gNB 115 and ng-eNB 120 may also be connected to the 5GC 110 via an NG interface, more specifically to the Access and Mobility Management Function (AMF) 130 of the 5GC 110 via an NG-C interface, and to the User Plane Function (UPF) 135 of the 5GC 110 via an NG-U interface. The transport network layer of the NG-U interface may be built on IP transport and may carry user plane PDUs between the NG-RAN node (e.g., the gNB 115 or ng-eNB 120) and the UPF 135 using the GTP protocol over UDP / IP. The NG-U may provide non-guaranteed delivery of user plane PDUs between the NG-RAN node and the UPF. The transport network layer of the NG-C interface may be built on IP transport. SCTP may be added on top of IP for reliable transmission of signaling messages. The application layer signaling protocol may be referred to as the NG Application Protocol (NGAP). The SCTP layer may provide guaranteed delivery of application layer messages. At the transport IP layer, point-to-point transmission may be used to deliver signaling PDUs. The NG-C interface can provide the following functions: NG interface management, UE context management, UE mobility management, forwarding of NAS messages, paging, PDU session management, configuration transfer, and alert message transmission.

[0019] The gNB 115 or ng-eNB 120 performs the following functions: radio bearer control, radio admission control, connection mobility control, radio resource management functions such as dynamic allocation of resources to UEs in both uplink and downlink (e.g., scheduling), IP and Ethernet header compression of data, encryption and integrity protection, selection of AMF at UE attachment when routing to AMF cannot be determined from information provided by the UE, routing of user plane data to UPF, routing of control plane information to AMF, connection setup and release, scheduling and transmission of paging messages, system broadcasting. The 5G LTE-R can host one or more of the following: scheduling and transmission of data information (e.g., derived from AMF), measurement and measurement reporting configuration for mobility and scheduling, transport level packet marking in the uplink, session management, support for network slicing, QoS flow management and mapping to data radio bearers, support for UEs in RRC inactive state, delivery functionality for NAS messages, radio access network sharing, dual connectivity, close interaction between NR and E-UTRA, and maintaining security and radio configuration for user plane 5G system (5GS) cellular IoT (CIoT) optimization.

[0020] The AMF 130 may host one or more of the following functions: NAS signaling termination, NAS signaling security, AS security control, CN inter-node signaling for mobility between 3GPP access networks, idle mode UE reachability (including control and execution of paging retransmissions), registration area management, support for intra-system and inter-system mobility, access authentication, access authorization including verification of roaming rights, mobility management control (subscription and policy), support for network slicing, Session Management Function (SMF) selection, 5GS CIoT optimization selection.

[0021] The UPF135 performs the following functions: anchor point for intra-RAT / inter-RAT mobility (where applicable), external PDU session point for interconnection to data networks, packet routing and forwarding, packet inspection and user plane part of policy rule enforcement, traffic usage reporting, traffic forwarding to data networks. It can host one or more of the following: an uplink classifier to support row routing, a branching point to support multi-homed PDU sessions, QoS processing for the user plane, e.g., packet filtering, gating, UL / DL rate enforcement, uplink traffic validation (Service Data Flow (SDF) to QoS flow mapping), and downlink packet buffering and downlink data notification triggering.

[0022] As shown in FIG. 1, the NG-RAN 105 can support a PC5 interface between two UEs 125 (e.g., UE 125A and UE 125B). In the PC5 interface, the direction of communication between the two UEs (e.g., from UE 125A to UE 125B or vice versa) may be referred to as a sidelink. Sidelink transmission and reception over the PC5 interface may be supported when the UE 125 is within NG-RAN 105 coverage and when the UE is out of NG-RAN 105 coverage, regardless of which RRC state the UE 125 is in. Support for V2X services over the PC5 interface may be provided by NR sidelink communication and / or V2X sidelink communication.

[0023] PC5-S signaling can be used for unicast link establishment with direct communication request / accept messages. A UE can self-assign a source Layer-2 ID for a PC5 unicast link, for example, based on the V2X service type. During the unicast link establishment procedure, a UE can send its source Layer-2 ID for the PC5 unicast link to a peer UE, e.g., the UE from which the destination ID was received from a higher layer. The pair of source Layer-2 ID and destination Layer-2 ID can uniquely identify the unicast link. The receiving UE can verify that the destination ID belongs to it and accept the unicast link establishment request from the source UE. During the PC5 unicast link establishment procedure, a PC5-RRC procedure on the access stratum can be invoked for UE sidelink context establishment purposes, as well as for AS layer configuration, capability exchange, etc. PC5-RRC signaling can enable the exchange of UE capabilities and AS layer configurations, such as sidelink radio bearer configuration, between a pair of UEs with established PC5 unicast links.

[0024] NR sidelink communication can support one of three types of transmission modes (e.g., unicast transmission, groupcast transmission, and broadcast transmission) for a pair of source Layer 2 ID and destination Layer 2 ID in an AS. The unicast transmission mode can be characterized by supporting one PC5-RRC connection between peer UEs for the pair, transmitting and receiving control information and user traffic between peer UEs on the sidelink, supporting sidelink HARQ feedback, supporting sidelink transmit power control, supporting RLC acknowledged mode (AM), and detecting radio link failures for the PC5-RRC connection. The groupcast transmission can be characterized by transmitting and receiving user traffic between UEs belonging to a group on the sidelink and supporting sidelink HARQ feedback. The broadcast transmission can be characterized by transmitting and receiving user traffic between UEs on the sidelink.

[0025] NR sidelink communications may use a source Layer-2 ID, a destination Layer-2 ID, and a PC5 link identifier. The source Layer-2 ID may identify the source of data in NR sidelink communications. The source Layer-2 ID may be 24 bits long and may be split into two bit strings at the MAC layer. One bit string may be the LSB portion (8 bits) of the source Layer-2 ID and may be forwarded to the sender's physical layer. This may identify the source of the intended data in the sidelink control information and may be used for packet filtering at the receiver's physical layer. The second bit The bit string may be the MSB portion (16 bits) of the source Layer-2 ID and may be carried in the Medium Access Control (MAC) header. This may be used for packet filtering at the MAC layer of the receiver. The destination Layer-2 ID can identify the target of data in NR sidelink communication. For NR sidelink communication, the destination Layer-2 ID may be 24 bits long and may be split into two bit strings at the MAC layer. One bit string may be the LSB portion (16 bits) of the destination Layer-2 ID and may be forwarded to the sender's physical layer. This may identify the target of the intended data in the sidelink control information and may be used for packet filtering at the receiver's physical layer. The second bit string may be the MSB portion (8 bits) of the destination Layer-2 ID and may be carried in the MAC header. This may be used for packet filtering at the MAC layer of the receiver. The PC5 link identifier can uniquely identify a PC5 unicast link within the UE for the lifetime of the PC5 unicast link. The PC5 link identifier may be used to indicate the PC5 unicast link for which the sidelink radio link failure (RLF) declaration was made and the PC5-RRC connection was released.

[0026] 2A and 2B illustrate example radio protocol stacks for the user plane and control plane, respectively, in accordance with some aspects of some of the various example embodiments of the present disclosure. As shown in FIG. 2A, the protocol stack for the user plane of the Uu interface (between the UE 125 and the gNB 115) includes Service Data Adaptation Protocol (SDAP) 201 and SDAP 211, Packet Data Convergence Protocol (PDCP) 202 and PDCP 212, Radio Link Control (RLC) 203 and RLC 213, MAC 204 and MAC 214, and sublayers of Layer 2 and physical (PHY) 205 and PHY 215 layers (Layer 1 is also referred to as L1).

[0027] The PHY 205 and PHY 215 provide transport channels 244 to the MAC 204 and MAC 214 sublayers. The MAC 204 and MAC 214 sublayers provide logical channels 243 to the RLC 203 and RLC 213 sublayers. The RLC 203 and RLC 213 sublayers provide RLC channels 242 to the PDCP 202 and PCP 212 sublayers. The PDCP 202 and PDCP 212 sublayers provide radio bearers 241 to the SDAP 201 and SDAP 211 sublayers. Radio bearers may be categorized into two groups: data radio bearers (DRBs) for user plane data and signaling radio bearers (SRBs) for control plane data. The SDAP 201 and SDAP 211 sublayers provide QoS flows 240 to the 5GC.

[0028] The main services and functions of the MAC204 or MAC214 sublayer include mapping between logical channels and transport channels, multiplexing / demultiplexing MAC service data units (SDUs) belonging to one or more different logical channels into / from transport blocks (TBs) passed to / from the physical layer on transport channels, scheduling information reporting, error correction using Hybrid Automatic Repeat Request (HARQ) (one HARQ entity per cell in the case of carrier aggregation (CA)), priority handling between UEs using dynamic scheduling, priority handling between logical channels of one UE using Logical Channel Prioritization (LCP), priority handling between overlapping resources of one UE, and padding. A single MAC entity may support multiple numerologies, transmission timings, and cells. Mapping restrictions in logical channel prioritization control the numerologies, cells, and transmission timings that a logical channel can use.

[0029] The HARQ function can guarantee delivery between peer entities at Layer 1. If the physical layer is not configured for downlink / uplink spatial multiplexing, a single HARQ process can support one TB, and if the physical layer is configured for downlink / uplink spatial multiplexing, a single HARQ process can support one or more TBs.

[0030] The RLC203 or RLC213 sublayer can support three transmission modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). The RLC configuration may be per logical channel independent of the numerology and / or transmission time, and automatic repeat request (ARQ) may operate with any of the numerologies and / or transmission times for which the logical channel is configured.

[0031] The main services and functions of the RLC203 or RLC213 sublayer depend on the transmission mode (e.g., TM, UM, or AM) and may include transport of upper layer PDUs, sequence numbers independent of PDCP sequence numbers (UM and AM), error correction via ARQ (AM only), segmentation (AM and UM) and resegmentation (AM only) of RLC SDUs, reassembly of SDUs (AM and UM), duplicate detection (AM only), RLC SDU discard (AM and UM), RLC re-establishment, and protocol error detection (AM only).

[0032] An automatic repeat request in the RLC203 or RLC213 sublayer may have the following characteristics: ARQ retransmits an RLC SDU or an RLC SDU segment based on an RLC status report, polling for RLC status notification may be used if required by RLC, and the RLC receiver may also trigger an RLC status notification after detecting a missing RLC SDU or an RLC SDU segment.

[0033] The main services and functions of the PDCP202 or PDCP212 sublayer may include forwarding of data (user plane or control plane), maintaining the PDCP sequence number (SN), header compression and decompression using the Robust Header Compression (ROHC) protocol, header compression and decompression using the EHC protocol, encryption and decryption, integrity protection and integrity verification, timer-based SDU discard, split bearer routing, duplication, reordering and in-order delivery, out-of-order delivery, and duplicate discarding.

[0034] The main services and functions of the SDAP 201 or SDAP 211 include mapping between QoS flows and data radio bearers, and marking QoS Flow IDs (QFIs) in both downlink and uplink packets. A single protocol entity of the SDAP may be configured for each individual PDU session.

[0035] As shown in Figure 2B, the control plane protocol stack of the Uu interface (between the UE 125 and the gNB 115) includes the PHY layer (Layer 1), the MAC, RLC, and PDCP sublayers of Layer 2, and the RRC206 and RRC216 sublayers, as described above. The main services and functions of the RRC206 and RRC216 sublayers on the Uu interface are broadcasting system information related to the AS and NAS, paging initiated by 5GC or NG-RAN, establishing, maintaining, and releasing RRC connections between the UE and the NG-RAN (including adding, modifying, and releasing carrier aggregation, and adding, modifying, and releasing dual connectivity between NR or E-UTRA and NR), security functions including key management, establishing, configuring, maintaining, and releasing SRBs and DRBs, mobility functions (handover and context transfer, UE cell selection and reselection, and controlling cell selection and reselection), and so on. The NAS207 and NAS227 layers are control protocols (terminated in the AMF on the network side) that perform functions such as authentication, mobility management, and security control.

[0036] Sidelink specific services and functions of the RRC sublayer over the Uu interface include configuration of sidelink resource allocation via system information or dedicated signaling, reporting of UE sidelink information, sidelink related measurement configuration and reporting, and reporting of UE assistance information for SL traffic patterns.

[0037] 3A, 3B, and 3C illustrate example mappings between logical channels and transport channels in the downlink, uplink, and sidelink, respectively, according to some aspects of some of various exemplary embodiments of the present disclosure. Different types of data transfer services may be provided by the MAC. Each logical channel type may be defined by what type of information is transferred. Logical channels may be classified into two groups: control channels and traffic channels. Control channels may be used only for the transfer of control plane information. The Broadcast Control Channel (BCCH) is a downlink channel for broadcasting system control information. The Paging Control Channel (PCCH) is a downlink channel that carries paging messages. The Common Control Channel (CCCH) is a channel for transmitting control information between a UE and a network. This channel may be used for UEs that do not have an RRC connection with the network. The Dedicated Control Channel (DCCH) is a point-to-point bidirectional channel that transmits dedicated control information between a UE and a network and may be used by UEs that have an RRC connection. The Traffic Channel may be used only for the transfer of user plane information. A dedicated traffic channel (DTCH) is a point-to-point channel dedicated to one UE for transferring user information. DTCH can exist in both the uplink and downlink. A sidelink control channel (SCCH) is a sidelink channel for transmitting control information (e.g., PC5-RRC and PC5-S messages) from one UE to other UEs. A sidelink traffic channel (STCH) is a sidelink channel for transmitting user information from one UE to other UEs. A sidelink broadcast control channel (SBCCH) is a sidelink channel for broadcasting sidelink system information from one UE to other UEs.

[0038] Downlink transport channel types include the Broadcast Channel (BCH), Downlink Shared Channel (DL-SCH), and Paging Channel (PCH). The BCH can be characterized by a fixed, predefined transport format. It must be broadcast throughout the cell's coverage area either as a single message or by beamforming different BCH instances. The DL-SCH can be characterized by support for HARQ, support for dynamic link adaptation by varying modulation, coding, and transmit power, the possibility of being broadcast throughout the cell, the possibility of using beamforming, support for both dynamic and semi-static resource allocation, and support for UE discontinuous reception (DRX) to enable UE power saving. The PCH can be characterized by support for UE discontinuous reception (DRX) to enable UE power saving (DRX cycles are indicated to the UE by the network), the requirement to be broadcast throughout the cell's coverage area either as a single message or by beamforming different BCH instances, and being mapped to physical resources that can also be dynamically used for traffic / other control channels.

[0039] In the downlink, the following connections may exist between logical channels and transport channels: BCCH may be mapped to BCH. BCCH may be mapped to DL-SCH. PCCH may be mapped to PCH. CCCH may be mapped to DL-SCH. DCCH may be mapped to DL-SCH. DTCH may be mapped to DL-SCH.

[0040] Uplink transport channel types include the Uplink Shared Channel (UL-SCH) and the Random Access Channel (RACH). The UL-SCH may be characterized by the possibility of using beamforming, support for dynamic link adaptation by varying transmit power and potentially modulation and coding, support for HARQ, and support for both dynamic and quasi-static resource allocation. The RACH may be characterized by limited control information and collision risk.

[0041] In the uplink, the following connections may exist between logical channels and transport channels: CCCH may be mapped to UL-SCH, DCCH may be mapped to UL-SCH, and DTCH may be mapped to UL-SCH.

[0042] Sidelink transport channel types include the Sidelink Broadcast Channel (SL-BCH) and the Sidelink Shared Channel (SL-SCH). The SL-BCH may be characterized by a predefined transport format. The SL-SCH may be characterized by support for unicast, groupcast, and broadcast transmissions; support for both UE autonomous resource selection and scheduled resource allocation by the NG-RAN; support for both dynamic and quasi-static resource allocation when the UE is assigned resources by the NG-RAN; support for HARQ; and support for dynamic link adaptation by varying transmit power, modulation, and coding.

[0043] In the sidelink, the following connections may exist between logical channels and transport channels: SCCH may be mapped to SL-SCH, STCH may be mapped to SL-SCH, and SBCCH may be mapped to SL-BCH.

[0044] 4A, 4B, and 4C illustrate example mappings between transport channels and physical channels in the downlink, uplink, and sidelink, respectively, in accordance with some aspects of some of various exemplary embodiments of the present disclosure. Physical channels in the downlink include a physical downlink shared channel (PDSCH), a physical downlink control channel (PDCCH), and a physical broadcast channel (PBCH). The PCH and DL-SCH transport channels are mapped to the PDSCH. The BCH transport channel is mapped to the PBCH. No transport channels are mapped to the PDCCH, and downlink control information (DCI) is transmitted via the PDCCH.

[0045] Physical channels in the uplink include the Physical Uplink Shared Channel (PUSCH), the Physical Uplink Control Channel (PUCCH), and the Physical Random Access Channel (PRACH). The UL-SCH transport channel may be mapped to the PUSCH, and the RACH transport channel may be mapped to the PRACH. No transport channel is mapped to the PUCCH, and uplink control information (UCI) is transmitted via the PUCCH.

[0046] The physical channels of the sidelink include the Physical Sidelink Shared Channel (PSSCH), The physical sidelink control channel (PSCCH), physical sidelink feedback channel (PSFCH), and physical sidelink broadcast channel (PSBCH) are included. The physical sidelink control channel (PSCCH) indicates the resources and other transmission parameters used by the UE for the PSSCH. The physical sidelink shared channel (PSSCH) transmits the TBs of the data itself as well as control information such as HARQ procedures and CSI feedback triggers. At least six OFDM symbols within a slot may be used for PSSCH transmission. The physical sidelink feedback channel (PSFCH) may carry HARQ feedback over the sidelink from the UE that is the intended recipient of the PSSCH transmission to the UE that performed the transmission. The PSFCH sequence may be transmitted in one PRB repeated across two OFDM symbols near the end of the sidelink resources within the slot. The SL-SCH transport channel may be mapped to the PSSCH. The SL-BCH may be mapped to the PSBCH. Transport channels are not mapped to the PSFCH, but sidelink feedback control information (SFCI) may be mapped to the PSFCH. Transport channels are not mapped to the PSCCH, but sidelink control information (SCI) may be mapped to the PSCCH.

[0047] Figures 5A, 5B, 5C, and 5D illustrate example radio protocol stacks for NR sidelink communications, respectively, in accordance with some aspects of various exemplary embodiments of the present disclosure. The AS protocol stack for the user plane at the PC5 interface (i.e., for STCH) may consist of the SDAP, PDCP, RLC, and MAC sublayers, and a physical layer. The user plane protocol stack is shown in Figure 5A. The AS protocol stack for the SBCCH at the PC5 interface may consist of the RRC, RLC, MAC sublayers, and a physical layer, as shown below in Figure 5B. To support the PC5-S protocol, PC5-S is placed above the PDCP, RLC, and MAC sublayers, and a physical layer in the control plane protocol stack for SCCH for PC5-S, as shown in Figure 5C. The AS protocol stack for the control plane for SCCH for RRC at the PC5 interface consists of the RRC, PDCP, RLC, and MAC sublayers, and a physical layer. The control plane protocol stack for SCCH for RRC is shown in Figure 5D.

[0048] Sidelink Radio Bearers (SLRBs) can be categorized into two groups: Sidelink Data Radio Bearers (SL DRBs) for user plane data and Sidelink Signaling Radio Bearers (SL SRBs) for control plane data. Separate SL SRBs using different SCCHs can be configured for PC5-RRC and PC5-S signaling, respectively.

[0049] The MAC sublayer can provide the following services and functions over the PC5 interface: radio resource selection, packet filtering, priority handling between uplink and sidelink transmissions for a given UE, and sidelink CSI reporting. Due to the restriction of logical channel prioritization in the MAC, only sidelink logical channels belonging to the same destination can be multiplexed into a MAC PDU for each unicast, groupcast, and broadcast transmission that may be associated with the destination. For packet filtering, an SL-SCH MAC header containing both the source and destination Layer 2 ID portions can be added to the MAC PDU. The logical channel identifier (LCID) included in the MAC subheader can uniquely identify a logical channel within the combination of the source and destination Layer 2 IDs.

[0050] The services and functions of the RLC sublayer may be supported for the sidelink. Both RLC unacknowledged mode (UM) and acknowledged mode (AM) may be used for unicast transmissions, while only UM may be used for groupcast or broadcast transmissions. In the case of UM, only one-way transmission may be supported for groupcast and broadcast.

[0051] The services and functions of the PDCP sublayer for the Uu interface may be supported for the sidelink with some restrictions: out-of-order delivery may only be supported for unicast transmission and may not support duplication over the PC5 interface.

[0052] The SDAP sublayer can provide the following services and functions over the PC5 interface: mapping between QoS flows and sidelink data radio bearers: There can be one SDAP entity per destination for one of unicast, groupcast, and broadcast associated with the destination.

[0053] The RRC sublayer can provide the following services and functions over the PC5 interface: transfer of PC5-RRC messages between peer UEs, maintenance and release of PC5-RRC connections between two UEs, and detection of sidelink radio link failures for PC5-RRC connections based on instructions from MAC or RLC. A PC5-RRC connection can be a logical connection between two UEs for a pair of source and destination Layer-2 IDs that can be considered established after a corresponding PC5 unicast link is established. There can be a one-to-one correspondence between PC5-RRC connections and PC5 unicast links. A UE can have multiple PC5-RRC connections with one or more UEs for different pairs of source and destination Layer-2 IDs. Separate PC5-RRC procedures and messages can be used by a UE to transfer UE capabilities and sidelink configurations, including SL-DRB configurations, to a peer UE. Both peer UEs can exchange their UE capabilities and sidelink configurations using separate bidirectional procedures in both sidelink directions.

[0054] FIG. 6 illustrates exemplary physical signals in the downlink, uplink, and sidelink in accordance with some aspects of various exemplary embodiments of the present disclosure. Demodulation reference signals (DM-RSs) may be used in the downlink, uplink, and sidelink and may be used for channel estimation. DM-RSs are UE-specific reference signals that may be transmitted along with downlink, uplink, or sidelink physical channels and may be used for channel estimation and coherent detection of the physical channels. Phase tracking reference signals (PT-RSs) may be used in the downlink, uplink, and sidelink and may be used to track phase and mitigate performance loss due to phase noise. PT-RSs may be primarily used to estimate and minimize the impact of common phase error (CPE) on system performance. Due to phase noise characteristics, PT-RS signals may have low density in the frequency domain and high density in the time domain. PT-RSs may occur when configured with DM-RSs in a network configuration. Positioning reference signals (PRSs) may be used in the downlink for positioning using different positioning techniques. The PRS may be used to measure the delay of downlink transmissions by correlating the received signal from the base station with a local replica in the receiver. The Channel State Information Reference Signal (CSI-RS) may be used in the downlink and sidelink. The CSI-RS may be used for, among other things, channel state estimation, Reference Signal Received Power (RSRP) measurement for mobility and beam management, and time / frequency tracking for demodulation. The CSI-RS may be configured UE-specific, although multiple users may share the same CSI-RS resource. The UE may determine CSI reports and transmit them in the uplink to the base station using the PUCCH or PUSCH. CSI reports may be carried in the sidelink MAC CE. The primary synchronization signal (PSS) and secondary synchronization signal (SSS) may be used for radio frame synchronization. The PSS and SSS may be used for cell search procedures during initial attach or for mobility purposes. The sounding reference signal (SRS) may be used in the uplink for uplink channel estimation. Similar to the CSI-RS, the SRS can serve as a QCL reference for other physical channels, as it may be configured to be transmitted quasi-colocated with the SRS. The sidelink PSS (S-PSS) and sidelink SSS (S-SSS) may be used in the sidelink for sidelink synchronization.

[0055] 7 illustrates examples of radio resource control (RRC) states and transitions between different RRC states in accordance with certain aspects of various exemplary embodiments of the present disclosure. A UE may be in one of three RRC states: an RRC connected state 710, an RRC idle state 720, and an RRC inactive state 730. After power-on, the UE may be in the RRC idle state 720, and the UE may use initial access to establish a connection with the network via an RRC connection establishment procedure to perform data transfer and / or conduct a voice call. Once the RRC connection is established, the UE may enter the RRC connected state 710. The UE can transition from the RRC idle state 720 to the RRC connected state 710 or from the RRC connected state 710 to the RRC idle state 720 using an RRC connection establishment / release procedure 740.

[0056] The RRC inactive state 730 may be used to reduce signaling load and latency resulting from frequent transitions from the RRC connected state 710 to the RRC idle state 720 when the UE transmits frequent small data. In the RRC inactive state 730, the AS context may be stored by both the UE and the gNB. This may result in a faster state transition from the RRC inactive state 730 to the RRC connected state 710. The UE may transition from the RRC inactive state 730 to the RRC connected state 710 or from the RRC connected state 710 to the RRC inactive state 730 using an RRC connection resume / deactivation procedure 760. The UE may transition from the RRC inactive state 730 to the RRC idle state 720 using an RRC connection release procedure 750.

[0057] FIG. 8 illustrates an example frame structure and physical resources according to some aspects of various exemplary embodiments of the present disclosure. Downlink, uplink, or sidelink transmissions may be organized into frames with a 10 ms duration consisting of ten 1 ms subframes. Each subframe may consist of 1, 2, 4, ... slots, and the number of slots per subframe may depend on the subcarrier spacing of the carrier on which the transmission occurs. The slot duration may be 14 symbols with a normal cyclic prefix (CP) or 12 symbols with an extended CP. The subframe may then be scaled in time depending on the subcarrier spacing used so that there are an integer number of slots in the subframe. FIG. 8 illustrates a resource grid in the time and frequency domains. Each element of the resource grid, which contains one symbol in time and one subcarrier in frequency, is called a resource element (RE). A resource block (RB) may be defined as 12 consecutive subcarriers in the frequency domain.

[0058] In some examples, with non-slot-based scheduling, packet transmission may occur over a portion of a slot, e.g., 2, 4, or 7 OFDM symbols, which may be referred to as a minislot. Minislots may be used for low-latency applications such as URLLC and operation in unlicensed bands. In some embodiments, minislots may also be used for fast flexible scheduling of services (e.g., preemption of URLLC for eMBB).

[0059] FIG. 9 illustrates example component carrier configurations in different carrier aggregation scenarios according to some aspects of various exemplary embodiments of the present disclosure. In carrier aggregation (CA), two or more component carriers (CCs) may be aggregated. A UE can simultaneously receive or transmit on one or more CCs depending on its capabilities. CA may be supported for both contiguous and non-contiguous CCs in the same band or different bands, as illustrated in FIG. 9. The gNB and UE can communicate using a serving cell. The serving cell may be associated with at least one downlink CC (e.g., associated with only one downlink CC or associated with a downlink CC and an uplink CC). The serving cell may be a primary cell (PCell) or a secondary cell (SCell).

[0060] The UE can adjust the timing of its uplink transmission using an uplink timing control procedure. It can use a timing advance (TA) to adjust the uplink frame timing relative to the downlink frame timing. The gNB can determine the desired timing advance setting and provide it to the UE. The UE can use the provided TA to determine its uplink transmit timing relative to the UE's observed downlink receive timing.

[0061] In the RRC connected state, the gNB may be responsible for maintaining the timing advance to keep L1 synchronized. Serving cells with uplinks to which the same timing advance applies and that use the same timing reference cell are grouped into a timing advance group (TAG). A TAG may contain at least one serving cell with a configured uplink. The mapping of serving cells to TAGs may be configured by RRC. For a primary TAG, the UE may use the PCell as the timing reference cell, except for shared spectrum channel access, where an SCell may also be used as the timing reference cell in some cases. For a secondary TAG, the UE may use any of the activated SCells of this TAG as the timing reference cell and may not need to change it unless necessary.

[0062] The timing advance update may be signaled by the gNB to the UE via a MAC CE command. Such a command may restart a TAG-specific timer that may indicate whether L1 can be synchronized; when the timer is running, L1 may be considered synchronized; otherwise, L1 may be considered unsynchronized (in which case uplink transmissions may only occur on the PRACH).

[0063] A UE with single timing advance capability for CA can simultaneously receive and / or transmit on multiple CCs corresponding to multiple serving cells (multiple serving cells grouped into one TAG) that share the same timing advance. A UE with multiple timing advance capability for CA can simultaneously receive and / or transmit on multiple CCs corresponding to multiple serving cells (multiple serving cells grouped into multiple TAGs) with different timing advances. NG-RAN may ensure that each TAG contains at least one serving cell. A non-CA-capable UE may receive on a single CC and transmit on a single CC corresponding to only one serving cell (one serving cell in one TAG).

[0064] The multi-carrier characteristics of the physical layer in the case of CA may be exposed to the MAC layer, and one HARQ entity may be required per serving cell. When CA is configured, the UE may have one RRC connection with the network. RRC connection establishment / re-establishment / During handover, one serving cell (e.g., PCell) may provide NAS mobility information. Depending on the UE capabilities, the SCell may be configured to form a set of serving cells together with the PCell. The set of serving cells configured for a UE may consist of one PCell and one or more SCells. Reconfiguration, addition, and deletion of SCells may be performed by RRC.

[0065] In a dual connectivity scenario, a UE may be configured with multiple cells including a Master Cell Group (MCG) for communicating with a master base station, a Secondary Cell Group (SCG) for communicating with a secondary base station, and two MAC entities, one for the MCG for communicating with the master base station and one for the SCG for communicating with the secondary base station.

[0066] FIG. 10 illustrates exemplary bandwidth portion configuration and switching according to some aspects of various exemplary embodiments of the present disclosure. A UE may be configured with one or more bandwidth portions (BWPs) 1010 in a given component carrier. In some examples, one of the one or more bandwidth portions may be active at a time. The active bandwidth portion may define the UE's operating bandwidth within the cell's operating bandwidth. For initial access, an initial bandwidth portion 1020 determined from system information may be used until the UE's configuration within the cell is received. For example, in bandwidth adaptation (BA) via BWP switching 1040, the UE's reception and transmission bandwidths may not be as large as the cell's bandwidth and may be adjusted. For example, the widths may be sequenced to change (e.g., shrink during periods of low activity to save power), the positions may move in the frequency domain (e.g., to increase scheduling flexibility), and the subcarrier spacing may be sequenced to change (e.g., to enable different services). The first active BWP 1020 may be the active BWP upon RRC (re)configuration of the PCell or activation of the SCell.

[0067] For a downlink BWP or an uplink BWP in a set of downlink or uplink BWPs, respectively, the UE may be provided with the following configuration parameters: subcarrier spacing (SCS), cyclic prefix, common RBs and a number of consecutive RBs, an index within the set of downlink or uplink BWPs by the respective BWP-Id, a set of BWP common parameters, and a set of BWP-specific parameters. A BWP may be associated with an OFDM numerology according to the subcarrier spacing and cyclic prefix configured for the BWP. For the serving cell, the UE may be provided with a default downlink BWP among the configured downlink BWPs. If the UE is not provided with a default downlink BWP, the default downlink BWP may be the initial downlink BWP.

[0068] A downlink BWP may be associated with a BWP inactivity timer. If the BWP inactivity timer associated with an active downlink BWP expires and a default downlink BWP is configured, the UE may perform a BWP switch to the default BWP. If the BWP inactivity timer associated with an active downlink BWP expires and a default downlink BWP is not configured, the UE may perform a BWP switch to the initial downlink BWP.

[0069] 11 illustrates an example time and frequency structure of synchronization signals and physical broadcast channel (PBCH) blocks (SSBs) in accordance with some aspects of various exemplary embodiments of the present disclosure. The SS / PBCH blocks (SSBs) each include primary and secondary synchronization signals (PSS, SSS), each occupying one symbol and 127 subcarriers (e.g., subcarriers 56 to 182 in FIG. 13). ) and a PBCH spanning three OFDM symbols and 240 subcarriers, but leaving an unused portion in the middle for SSBs on one symbol, as shown in Figure 13. The possible time locations of the SSBs within a half-frame may be determined by the subcarrier spacing, and the periodicity of the half-frames in which the SSBs are transmitted may be configured by the network. During a half-frame, different SSBs may be transmitted in different spatial directions (i.e., using different beams spanning the cell's coverage area).

[0070] The PBCH may be used to carry the Master Information Block (MIB), which is used by the UE during cell search and initial access procedures. The UE may first decode the PBCH / MIB to receive other system information. The MIB may provide the UE with the parameters necessary to acquire System Information Block 1 (SIB1), more specifically, the information necessary to monitor the PDCCH for scheduling the PDSCH carrying SIB1. Additionally, the MIB may indicate cell barring status information. The MIB and SIB1 may be collectively referred to as Minimum System Information (SI), and SIB1 may be referred to as Remaining Minimum System Information (RMSI). The other System Information Blocks (SIBs) (e.g., SIB2, SIB3, ..., SIB10, and SIBpos) may be referred to as Other SIs (OSI). The OSI may be broadcast periodically on the DL-SCH, may be broadcast on demand on the DL-SCH (e.g., upon request from a UE in RRC idle, RRC inactive, or RRC connected state), or may be sent in a dedicated manner to RRC connected UEs on the DL-SCH (e.g., upon request, if configured by the network, from a UE in RRC connected state, or if the UE has an active BWP with no common search space configured).

[0071] 12A and 12B illustrate examples of non-transparent and transparent mobile non-terrestrial networks (NTNs), respectively, in accordance with some aspects of some of the various exemplary embodiments of the present disclosure. Networks 1200 and 1250 are connected to data networks 1203 and 1253 via 5G-CNs 1206 and 1256, respectively. Networks 1200 and 1250 can improve network access for three categories: providing services where services are not feasible over the terrestrial network, offloading traffic from the terrestrial network, and providing NTN availability in scenarios that result in temporary outages or disruptions to the terrestrial network.

[0072] In the non-transparent architecture 1200, the satellite 1223 may include all or part of the 5G RAN 1212 to transmit / receive "satellite-friendly" signals to / from the UE 1205. The 5G RAN 1212 may include a gNB 1213. A Uu interface 1205 may be used between the UE 1205 and the satellite 1223. A gateway 1209 may transfer signals from the 5G-CN 1206 to the 5G RAN 1212 and vice versa. A radio link NG may be used between the 5G-CN 1206 and the gateway 1209. An inter-satellite link (ISL) may be used as a transport link between the NTN platforms 1213, 1212.

[0073] In the transparent architecture 1250, the satellite 1273 can relay "satellite-friendly" signals between the 5G RAN 1262 and the UE 1275. The 5G RAN 1263 can include a gNB 1263. A Uu interface may be used between the UE 1270 and the satellite 1273. A gateway 1259 can forward signals from the 5G-RAN 1263 to the satellite 1273 and vice versa. A radio link NG may be used between the 5G-CN 1256, the 5G-RAN 1262, and the gateway 1209. An inter-satellite link (ISL) may be used as a transport link between the NTN platforms 1213, 1212.

[0074] In some examples, NTN networks 1200, 1250 may be used to provide eMBB services in unserved / underserved areas and on mobile platforms (e.g., ships, aircraft). Additionally, networks 1200, 1250 can provide a unique platform for combining terrestrial and NTN networks. In some scenarios, networks 1200, 1250 may be utilized to offload traffic from a 5G terrestrial network (e.g., network 100) for delivering broadcast and multicast services or public safety messages to UEs in home premises or onboard mobile platforms.

[0075] In some other examples, the NTN 1200, 1250 may be used to provide mMTC services for both wide-area and local-area IoT services. For wide-area IoT services, IoT devices can connect to the NTN via satellite or gNB. For local-area IoT services, the NTN can provide connectivity between IoT and 5G-RAN services IoT devices by collecting information belonging to a group of sensors deployed under the coverage of one or more cells.

[0076] In some other examples, the NTN 1200, 1250 may be used in maritime scenarios. The NTN is useful for facilitating communication between the 5G-CN and the Seaborn platform. The NTN 1200, 1250 may be utilized for paging notifications and emergency requests (e.g., to inform other vessels of the location of a vessel in danger) to improve safety at sea.

[0077] 13 illustrates an example system 1300 for Doppler frequency measurement and correction between a UE and a satellite of an NTN network, in accordance with some aspects of various exemplary embodiments of the present disclosure. The system 1300 includes a UE 1305 and a satellite 1303. The system 1300 can be connected to a data network (e.g., network 1203, 1253) via a network architecture (e.g., network architecture 1200, 1250). The satellite 1303 can include a gNB or can be connected to a gNB as described in FIGS. 12A and 12B.

[0078] Doppler frequency or Doppler shift is the change in frequency of an electromagnetic wave relative to a fixed wireless device (e.g., satellite 1303) or a mobile wireless device (e.g., UE 1305) that is moving relative to the mobile wireless device. Doppler shift is calculated as follows: ΔF=Fo*V*cos(θ) / c(1)

[0079] where F is the frequency of the electromagnetic wave propagating through the medium between the UE 1305 and the satellite 1305, V is the velocity of the UE 1305, the angle θ 1307 is the angle between the direction of motion of the UE 1305 and the direction of the wave traveling from the satellite 1303 and the UE 1305, or vice versa, and c is the speed of light. In some examples, equation (1) assumes that the position and course of the satellite may be known to the UE 1305. In some examples, the satellite 1303 may transmit its position, velocity, and course to the UE 1305 to allow the UE 1305 to calculate the Doppler shift.

[0080] In some examples, the UE 1305 may perform measurements to estimate the Doppler shift without assistance from the satellite 1303. In some scenarios, the satellite 1303 may provide velocity, position, or other relevant information, allowing the UE to calculate the Doppler shift and correct the frequency of the electromagnetic waves.

[0081] FIG. 14 illustrates exemplary components of a user equipment for transmission / reception in accordance with some aspects of various exemplary embodiments of the present disclosure. All or some of the blocks and functions of FIG. 14 may reside within or be performed by the user equipment 1400 (e.g., UE 1220, 1270). The antenna 1410 may be used for transmitting and receiving electromagnetic signals. The antenna 1410 may include one or more antenna elements and may enable different input / output antenna configurations, including a multiple-input multiple-output (MIMO) configuration, a multiple-input single-output (MISO) configuration, and a single-input multiple-output (SIMO) configuration. In some embodiments, the antenna 1410 may enable a massive MIMO configuration with tens or hundreds of antenna elements. The antenna 1410 may enable other multi-antenna techniques, such as beamforming. In some examples, depending on the capabilities of the UE 1400 or the type of the UE 1400 (e.g., a low-complexity UE), the UE 1500 may support only a single antenna.

[0082] The transceiver 1420 can communicate bidirectionally over the wireless links described herein via the antenna 1410. For example, the transceiver 1420 may represent a wireless transceiver in a UE and may communicate bidirectionally with a wireless transceiver in a base station, or vice versa. The transceiver 1420 can include a modem to modulate packets, provide the modulated packets to the antenna 1410 for transmission, and demodulate packets received from the antenna 1410.

[0083] The memory 1430 may include RAM and ROM. The memory 1430 may store computer-readable computer-executable code 1435 that includes instructions that, when executed, cause the processor to perform various functions described herein. In some examples, the memory 1430 may include a basic input / output system (BIOS) that may control basic hardware or software operations, such as interaction with peripheral components or devices, among other things.

[0084] The processor 1440 may include a hardware device having processing capabilities (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some examples, the processor 1440 may be configured to operate a memory using a memory controller. In other examples, the memory controller may be integrated into the processor 1440. The processor 1440 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1430) to cause the UE 1400 to perform various functions.

[0085] Central processing unit (CPU) 1450 can perform basic arithmetic, logic, control, and input / output (I / O) operations specified by computer instructions in memory 1430. User equipment 1400 may include additional peripheral components such as a graphics processing unit (GPU) 1460 and a global positioning system (GPS) 1470. GPU 1460 is dedicated circuitry for rapid manipulation and modification of memory 1430 to accelerate processing performance of user equipment 1400 and / or base station 1405. GPS 1470 may be used to enable location-based services or other services, for example, based on the geographic location of user equipment 1400.

[0086] The TCA module 1480 may include functionality to perform measurements to calculate the Doppler shift between the UE (e.g., the UE 1305, the satellite, or the gNB 1303) and correct the frequency of the received signal at the UE 1305.

[0087] FIG. 15 illustrates example components of a BS (e.g., a gNB onboard a satellite 1303) for transmission and / or reception in accordance with some aspects of various exemplary embodiments of the present disclosure. All or a subset of the blocks and functions of FIG. 15 may be within or performed by the BS 1500. The antenna 1510 may be used to transmit or receive electromagnetic signals. The antenna 1510 may include one or more antenna elements and may enable different input / output antenna configurations, including a multiple-input multiple-output (MIMO) configuration, a multiple-input single-output (MISO) configuration, and a single-input multiple-output (SIMO) configuration. In some embodiments, the antenna 1510 may enable a massive MIMO configuration with tens or hundreds of antenna elements. The antenna 1510 may enable other multi-antenna techniques, such as beamforming.

[0088] The transceiver 1520 can communicate bidirectionally over the wireless links described herein via the antenna 1510. For example, the transceiver 1520 may represent a wireless transceiver in a UE and may communicate bidirectionally with a wireless transceiver in a base station, or vice versa. The transceiver 1520 may include a modem for modulating packets, providing the modulated packets to the antenna 1410 for transmission, and demodulating packets received from the antenna 1510.

[0089] The memory 1530 may include RAM and ROM. The memory 1530 may store computer-readable computer-executable code 1535 that includes instructions that, when executed, cause the processor to perform various functions described herein. In some examples, the memory 1530 may include a basic input / output system (BIOS) that may control basic hardware or software operations, such as interaction with peripheral components or devices, among other things.

[0090] The processor 1540 may include a hardware device having processing capabilities (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some examples, the processor 1540 may be configured to operate a memory using a memory controller. In other examples, the memory controller may be integrated into the processor 1540. The processor 1540 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1530) to cause the base station 1500 to perform various functions.

[0091] Central processing unit (CPU) 1550 may perform basic arithmetic, logic, control, and input / output (I / O) operations specified by computer instructions in memory 1530 .

[0092] The Doppler module 1560 can perform measurements to calculate the Doppler shift of the UE and transmit the Doppler shift to the UE to correct the frequency of the received waves.

[0093] 16 is a flow diagram of an exemplary method 1600 for a UE to perform Doppler measurements and calculations in accordance with some aspects of various exemplary embodiments of the present disclosure. The method 1600 is described herein with reference to the exemplary system 1300 of FIG.

[0094] In step 1603, the UE performs measurements to calculate the Doppler shift. The Doppler shift can be estimated from measuring a DL reference signal (e.g., DM-RS, CSI-RS). In some examples, the Doppler shift measurement may be performed periodically.

[0095] In step 1607, the UE transmits the measured Doppler to a satellite (e.g., satellite 1303). The UE may transmit the Doppler shift to the satellite via the PUCCH.

[0096] In step 1611, the satellite may correct the frequency of the received signal based on the measured Doppler shift from the UE and transmit the corrected signal to the UE. In some examples, the satellite may also perform measurements to calculate the Doppler shift.

[0097] In step 1615, the UE may correct the frequency of the received signal based on the calculated Doppler frequency.

[0098] 17 is a flow diagram of an exemplary method 1700 for a UE to perform Doppler shift measurements in accordance with some aspects of various exemplary embodiments of the present disclosure. The method 1700 is described herein with reference to the exemplary system 1300 of FIG.

[0099] In step 1703, the UE performs measurements to calculate the Doppler shift. The Doppler shift can be estimated from measuring a DL reference signal (e.g., DM-RS, CSI-RS). In some examples, the Doppler shift measurements may be performed periodically.

[0100] In step 1707, the UE calculates the Doppler shift based on the measurements.

[0101] In step 1711, the UE corrects the frequency of the received signal by the calculated Doppler shift. The UE can then perform frequency correction based on the measurement. In some examples, the UE can use automatic frequency control (AFC) to demodulate the wider bandwidth signal and perform a fast Fourier transform (FFT) to find the signal peaks to estimate the Doppler shift.

[0102] 18A is a flow diagram of an exemplary method for a satellite (e.g., satellite 1303) to perform Doppler shift measurements and calculations in accordance with some aspects of various exemplary embodiments of the present disclosure. The method 1800 is described herein with reference to the exemplary network 1300 of FIG.

[0103] In step 1803, a satellite (e.g., satellite 1305) measures the Doppler shift of each UE (UE 1305). The satellite can calculate optimal settings for each UE based on the measurement results.

[0104] In step 1807, the satellite transmits the Doppler shift and the calculated optimal setting to the UE.

[0105] 18B is a flow diagram of an exemplary method 1850 for a UE (e.g., a satellite 1303) to perform Doppler shift correction, in accordance with some aspects of various exemplary embodiments of the present disclosure. The method 1850 is described herein with reference to the exemplary network 1300 of FIG.

[0106] In step 1853, the UE receives the Doppler shift from a satellite (eg, satellite 1305).

[0107] In step 1857, the UE corrects the frequency of the received signal by the Doppler shift received from the satellite.

[0108] In the methods 1800, 1850, the satellite, rather than the UE, performs most of the processing. In some examples, the satellite may use a multi-user detection algorithm to estimate the received signal from the UE.

[0109] The example blocks and modules described in this disclosure with respect to various example embodiments may be implemented or performed using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. Examples of general-purpose processors include, but are not limited to, a microprocessor, any conventional processor, controller, microcontroller, or state machine. In some examples, a processor may be implemented using a combination of devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration).

[0110] The functions described in this disclosure may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. Instructions or code may be stored on or transmitted to a computer-readable medium to implement the functions. Other examples for implementing the functions disclosed herein are also within the scope of this disclosure. Implementation of the functions may be via physically co-located or distributed elements (e.g., in various locations), including being distributed such that some of the functions are implemented in different physical locations.

[0111] Computer-readable media include, but are not limited to, non-transitory computer storage media. Non-transitory storage media may be accessed by general-purpose or special-purpose computers. Examples of non-transitory storage media include, but are not limited to, random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disc (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage, etc. Non-transitory media may be used to carry or store desired program code means (e.g., instructions and / or data structures) and may be accessed by a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. In some examples, software / program code may be transmitted from a remote source (e.g., a website, a server, etc.) using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave. In such examples, coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are within the definition of medium. Combinations of the above examples are also within the scope of computer-readable media.

[0112] As used in this disclosure, the use of the term "or" in a list of items indicates an inclusive list. A list of items can begin with a phrase such as "at least one" or "one or more." For example, a list of at least one of A, B, or C includes A or B or C or AB (i.e., A and B) or AC or BC or ABC (i.e., A and B and C). Also, as used in this disclosure, The phrase "based on" preceding a list of conditions should not be construed as "based only on" the set of conditions, but rather as "based at least in part on" the set of conditions. For example, a result described as "based on condition A" could be based on both condition A and condition B without departing from the scope of the present disclosure.

[0113] As used herein, the terms "comprise," "include," or "contain" may be used interchangeably, have the same meaning, and should be construed as inclusive and open-ended. The terms "comprise," "include," or "contain" may be used before a list of elements to indicate that at least all of the listed elements in the list are present, but that other elements not in the list may also be present. For example, if A contains B and C, then both {B, C} and {B, C, D} are within the scope of A.

[0114] The present disclosure, in connection with the accompanying drawings, describes exemplary configurations that do not represent every example that may be implemented or every configuration within the scope of the present disclosure. The term "exemplary" should not be interpreted as "preferred" or "advantageous over other examples," but rather as "an example, instance, or example." By reading this disclosure, including the description of the embodiments and drawings, those skilled in the art will understand that the technology disclosed herein may be implemented using alternative embodiments. Those skilled in the art will understand that embodiments, or specific features of the embodiments described herein, can be combined to arrive at yet other embodiments for implementing the technology described in this disclosure. Thus, the present disclosure is not limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. 1. A method of Doppler shift calculation by a user equipment (UE), comprising: measuring a downlink (DL) signal transmitted from a satellite; estimating the Doppler shift from the measurements; transmitting the Doppler shift to the satellite; receiving a message from the satellite that includes a Doppler shift correction; applying the Doppler shift correction to an uplink transmission signal.

2. The method of claim 1 , wherein the measuring step comprises measuring a downlink sounding reference signal.

3. 2. The method of claim 1, wherein the Doppler shift comprises a frequency shift between a first frequency associated with the downlink (DL) signal transmitted from the satellite and a second frequency associated with the DL signal received by the user equipment (UE) due to motion of the UE.

4. The method of claim 1 , wherein estimating the Doppler shift comprises determining a frequency at which the downlink (DL) signal has a peak.

5. The method of claim 1 , wherein the received message embodies a Doppler shift correction signal.

6. 1. A method for satellite-based Doppler shift measurement, comprising: receiving a message including a measurement report from a user equipment (UE); calculating a Doppler shift correction from the measurement reports; applying the Doppler shift correction to a downlink (DL) signal; transmitting the DL signal to a user equipment (UE).

7. 7. The method of claim 6, wherein the measurement report includes a Doppler shift value that is a difference between a first frequency of the downlink (DL) signal transmitted from the satellite and a second frequency of the DL signal received by the user equipment (UE).

8. 1. A method of Doppler shift calculation by a user equipment (UE), comprising: measuring a downlink (DL) signal transmitted from a satellite; estimating a Doppler shift from the measurements and estimating a Doppler shift correction; applying the Doppler shift correction to an uplink transmission signal.

9. 9. The method of claim 8, wherein the measured downlink (DL) signal comprises measuring a downlink sounding reference signal.

10. 10. The method of claim 9, wherein the Doppler shift comprises a frequency shift between a first frequency associated with the downlink (DL) signal transmitted from the satellite and a second frequency associated with the downlink (DL) signal received by the user equipment (UE) due to motion of the UE.

11. The step of estimating the Doppler shift comprises: The method of claim 10, comprising determining a frequency having:

12. The method of claim 10 further comprising transmitting an uplink (UL) signal to the satellite.

13. 1. A method for Doppler shift correction by a user equipment (UE), comprising: receiving a message signal from a satellite that reflects a Doppler shift of a signal transmitted from the satellite to the UE; generating and applying the Doppler shift correction to an uplink transmission signal based on the Doppler shift.

14. 14. The method of claim 13, wherein the Doppler shift is a difference between a first frequency of the uplink (UL) signal transmitted from the user equipment (UE) and a second frequency of the UL signal received by the satellite.

15. 1. A method for satellite-based Doppler shift measurement, comprising: measuring an uplink (UL) signal transmitted from a user equipment (UE); - estimating the Doppler shift of each UE from each of its respective measurements; transmitting the respective Doppler shifts to each of the UEs.

16. 16. The method of claim 15, wherein measuring the uplink (UL) signal comprises measuring an uplink sounding reference signal.

17. 17. The method of claim 16, wherein the Doppler shift comprises the frequency shift between a first frequency associated with the uplink (UL) signals transmitted from a user equipment (UE) and a second frequency associated with the respective UL signals received by the satellite due to movement of the UE.

18. A user equipment (UE), A transceiver, measuring a downlink (DL) signal transmitted from the satellite to achieve a measurement result; transmitting the measurement results to the satellite; a transceiver configured to receive a message signal reflecting a Doppler shift correction from the satellite; a processor in communication with the transceiver, estimating a Doppler shift correction from the measurements; a processor further configured to apply the Doppler shift correction to an uplink (UL) signal for transmission by the transceiver; A user equipment (UE) including:

19. A satellite, A transceiver, measuring an uplink (UL) signal received from a user equipment (UE); a transceiver configured to transmit a message signal to each UE indicative of a Doppler shift of the UE; a processor in communication with the transceiver, a processor configured to estimate the Doppler shift from the measured UL signals received from each UE; satellites, including

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