Handover between terrestrial and non-terrestrial networks

Abstract

Certain aspects of the present disclosure provide a method of wireless communication by a user equipment (UE). The method generally includes performing a mobility procedure to establish a connection in a target radio access technology (RAT) while maintaining a context established in a source RAT, where one of the source RAT or the target RAT is a terrestrial network (TN) RAT and the other is a non-terrestrial network (NTN) RAT, and transmitting a tracking area update (TAU) request after establishing the connection in the target RAT.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. patent application No. 17 / 709,382, filed on March 30, 2022, which is assigned to the assignee of the present application and is hereby expressly incorporated by reference in its entirety, as if fully set forth below and for all applicable purposes. Background Art Technical Field

[0003] Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for transitioning a user equipment (UE) from a terrestrial network (TN) to a non-terrestrial network (NTN).

[0004] Related technologies

[0005] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, or other similar types of services. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available wireless communication system resources with the multiple users.

[0006] Although wireless communication systems have made tremendous technical progress over the years, challenges still exist. For example, complex and dynamic environments can still attenuate or block signals between wireless transmitters and wireless receivers. Therefore, there is a continuous desire to improve the technical performance of wireless communication systems, including, for example: improving the speed and data carrying capacity of communications, improving the efficiency of using shared communication media, reducing the power used by transmitters and receivers when performing communications, improving the reliability of wireless communications, avoiding redundant transmission and / or reception and related processing, improving the coverage area of ​​wireless communications, increasing the number and types of devices that can access wireless communication systems, increasing the ability of different types of devices to communicate with each other, increasing the number and types of wireless communication media available for use, etc. Therefore, there is a need to further improve wireless communication systems to overcome the above-mentioned technical challenges and other challenges. Summary of the invention

[0007] One aspect provides a method of wireless communication by a user equipment (UE). The method includes: performing a mobility procedure to establish a connection in a target radio access technology (RAT) while maintaining a context established in a source RAT, wherein one of the source RAT or the target RAT is a terrestrial network (TN) RAT and the other is a non-terrestrial network (NTN) RAT; and transmitting a tracking area update (TAU) request after establishing the connection in the target RAT.

[0008] Another aspect provides a method for wireless communication by a network entity. The method includes: sending a system information block (SIB) indicating support for a radio resource control (RRC) connection reestablishment procedure for a UE between a target RAT and a source RAT, wherein one of the source RAT or the target RAT is a TN RAT and the other is an NTN RAT; and participating in the RRC connection reestablishment procedure with the UE to maintain a context established in the source RAT.

[0009] In another aspect, a method of wireless communication by a network entity is provided. The method includes: participating in a mobility procedure to transition a UE from a source RAT to a target RAT, wherein one of the source RAT or the target RAT is a TN RAT and the other is an NTN RAT; retrieving a context of the UE from the source RAT; and forwarding data from the source RAT to the UE.

[0010] Other aspects provide: an apparatus operable to, configured to, or otherwise adapted to perform any one or more of the foregoing methods and / or those described elsewhere herein; a non-transitory computer-readable medium comprising instructions that, when executed by a processor of the apparatus, cause the apparatus to perform the foregoing methods and those described elsewhere herein; a computer program product embodied on a computer-readable storage medium comprising code for performing the foregoing methods and those described elsewhere herein; and / or an apparatus comprising components for performing the foregoing methods and those described elsewhere herein. By way of example, an apparatus may include a processing system, a device having a processing system, or a processing system cooperating through one or more networks.

[0011] For purposes of illustration, the following description and drawings set forth certain features. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings depict certain features of the various aspects described herein and should not be considered to limit the scope of the disclosure.

[0013] Figure 1 An example wireless communication network is depicted.

[0014] Figure 2 An example disaggregated base station architecture is depicted.

[0015] Figure 3 Aspects of an example base station and example user equipment are depicted.

[0016] Figure 4A , Figure 4B , Figure 4C and Figure 4DVarious example aspects of data structures for a wireless communication network are described.

[0017] Figure 5 A diagram illustrating an example wireless communication network having non-terrestrial network entities is depicted.

[0018] Figure 6 An example general mobility scenario is depicted.

[0019] Figure 7 An example conventional multi-RAT mobility scenario is depicted.

[0020] Figure 8 Depicted are example mobility scenarios between RATs sharing a common core network (CN).

[0021] Fig. 9 An example Globally Unique Temporary Identifier (GUTI) format is depicted.

[0022] Fig.10 Depicted are example mobility scenarios of a UE between a terrestrial network (TN) and a non-terrestrial network (NTN), in which aspects of the present disclosure may be applied.

[0023] Fig.11 Depicted is an example structure for signaling a handover (access change) update type via a Tracking Area Update (TAU) request.

[0024] Fig.12 A method for wireless communication is described.

[0025] Fig.13 A method for wireless communication is described.

[0026] Fig.14 A method for wireless communication is described.

[0027] Fig.15 Aspects of an example communications device are depicted.

[0028] Fig.16 Aspects of an example communications device are depicted.

[0029] Fig.17 Aspects of an example communications device are depicted. DETAILED DESCRIPTION

[0030] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for performing handover of a user equipment (UE) between a terrestrial network (TN) and a non-terrestrial network (NTN).

[0031] In some cases, the NTN may provide extended radio coverage to user equipment (UE), for example, in rural areas where reliable coverage of the TN is not possible or is cost-prohibitive. In some cases, when a UE is connected (in a radio resource control, RRC, connected state) and moves from the NTN to the TN (or vice versa), conventional connection reestablishment procedures may not be supported. As a result, the UE network context may be lost, and the UE may have to establish a new connection in the target network, resulting in increased latency and service interruption. In addition, data available at the source network (which might have been retrieved and forwarded using the UE context) may be lost.

[0032] For example, connection reestablishment typically occurs when the UE detects a radio link failure (RLF) or when a handover procedure fails. If the UE recovers, the UE initiates a connection reestablishment procedure, unless the UE recovers in a different radio access technology (RAT), in which case the UE gives up and enters an idle state (e.g., RRC_IDLE). This is typically because the other RAT will not be "ready" for the UE, as it will not have a UE context including the UE identity. NTN and TN are typically considered to be different RATs, and connection reestablishment is typically not supported when moving between NTN and TN.

[0033] However, aspects of the present disclosure provide techniques that allow a UE to perform an RRC connection re-establishment when switching between an NTN and a TN. Thus, the techniques provided herein may allow a UE to maintain a network context and avoid having to establish a new connection in a target network. Thus, these techniques may allow a UE to reduce latency and avoid service interruption. In addition, data available at a source network may be retrieved from the source network and forwarded to the UE.

[0034] Introduction to wireless communication networks

[0035] The techniques and methods described herein can be used in various wireless communication networks. Although various aspects may be described herein using terms commonly associated with 3G, 4G and / or 5G wireless technologies, various aspects of the present disclosure may also be applicable to other communication systems and standards not explicitly mentioned herein.

[0036] Figure 1 An example of a wireless communication network 100 is depicted in which various aspects described herein may be implemented.

[0037] In general, the wireless communication network 100 includes various network entities (alternatively, network elements or network nodes). A network entity is typically a communication device and / or a communication function performed by a communication device (e.g., user equipment (UE), base station (BS), component of a BS, server, etc.). For example, various functions of a network and various devices associated with and interacting with the network may be considered network entities. In addition, the wireless communication network 100 includes ground aspects, such as ground-based network entities (e.g., BS 102), and non-ground aspects, such as satellites 140 and aircraft 145, which may include airborne network entities (e.g., one or more BSs) capable of communicating with other network elements (e.g., ground BSs) and user equipment.

[0038] In the depicted example, the wireless communication network 100 includes a BS 102, a UE 104, and one or more core networks (such as an evolved packet core (EPC) 160 and a 5G core (5GC) network 190) that interoperate to provide communication services over various communication links (including wired and wireless links).

[0039] Figure 1 Various example UEs 104 are depicted, which may more generally include: a cellular phone, a smart phone, a Session Initiation Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player, a camera, a game console, a tablet computer, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, an Internet of Things (IoT) device, an Always-On (AON) device, an edge processing device, or other similar devices. UE 104 may also be more generally referred to as a mobile device, a wireless device, a wireless communication device, a station, a mobile station, a user station, a mobile user station, a mobile unit, a user unit, a wireless unit, a remote unit, a remote device, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, and others.

[0040] BS 102 wirelessly communicates with (e.g., transmits signals to or receives signals from) UE 104 via communication link 120. Communication link 120 between BS 102 and UE 104 may include uplink (UL) (also referred to as a reverse link) transmissions from UE 104 to BS 102 and / or downlink (DL) (also referred to as a forward link) transmissions from BS 102 to UE 104. In various aspects, communication link 120 may employ multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity.

[0041] BS 102 may generally include: a Node B, an enhanced Node B (eNB), a next generation enhanced Node B (ng-eNB), a next generation Node B (gNB or gNodeB), an access point, a base transceiver, a radio base station, a radio transceiver, a transceiver function, a transmission and reception point, and / or the like. Each of BS 102 may provide communication coverage for a respective geographic coverage area 110, which may sometimes be referred to as a cell, and may overlap in some cases (e.g., a small cell 102' may have a coverage area 110' that overlaps with a coverage area 110 of a macro cell). For example, a BS may provide communication coverage for a macro cell (covering a relatively large geographic area), a pico cell (covering a relatively small geographic area, such as a stadium), a femto cell (a relatively small geographic area (e.g., a home)), and / or other types of cells.

[0042] Although BS102 is depicted as a single communication device in various aspects, BS102 can be implemented in various configurations. For example, one or more components of the base station may be decomposed, including a central unit (CU), one or more distributed units (DU), one or more radio units (RU), a near real-time (near RT) RAN intelligent controller (RIC), or a non-real-time (non-RT) RIC, to name a few examples. In another example, various aspects of the base station may be virtualized. More generally, a base station (e.g., BS102) may include components located at a single physical location or components located at various physical locations. In an example in which the base station includes components located at various physical locations, the various components may each perform a function so that the various components together implement functions similar to those of a base station located at a single physical location. In some aspects, a base station including components located at various physical locations may be referred to as a decomposed radio access network architecture, such as an open RAN (O-RAN) or virtualized RAN (VRAN) architecture. Figure 2 An example decomposed base station architecture is depicted and described.

[0043] Different BSs 102 within the wireless communication network 100 may also be configured to support different radio access technologies (such as 3G, 4G, and / or 5G). For example, a BS 102 configured for 4G LTE (collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC 160 via a first backhaul link 132 (e.g., an S1 interface). A BS 102 configured for 5G (e.g., 5G NR or Next Generation RAN (NG-RAN)) may interface with the 5GC 190 via a second backhaul link 184. The BSs 102 may communicate with each other directly or indirectly (e.g., via the EPC 160 or the 5GC 190) over a third backhaul link 134 (e.g., an X2 interface), which may be wired or wireless.

[0044] The wireless communication network 100 may subdivide the electromagnetic spectrum into various categories, frequency bands, channels, or other characteristics. In some aspects, the subdivision is provided based on wavelength and frequency, where frequency may also be referred to as a carrier, subcarrier, channel, tone, or subband. For example, 3GPP currently defines frequency range 1 (FR1) as including 410 MHz-7125 MHz, which is often (interchangeably) referred to as "below 6 GHz". Similarly, 3GPP currently defines frequency range 2 (FR2) as including 24,250 MHz-52,600 MHz, which is sometimes (interchangeably) referred to as "millimeter wave" ("mmW" or "mmWave"). A base station (e.g., a mmWave base station, such as BS 180) configured to communicate using mmWave / near mmWave radio bands may utilize beamforming (e.g., 182) with a UE (e.g., 104) to improve path loss and distance.

[0045] The communication link 120 between the BS 102 and, for example, the UE 104 may be through one or more carriers, which may have different bandwidths (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, and / or other MHz) and may be aggregated in various aspects. The carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​compared to UL).

[0046] Communications using higher frequency bands may have higher path losses and shorter distances than communications at lower frequencies. Figure 1 180) may utilize beamforming 182 with UE 104 to improve path loss and distance. For example, BS 180 and UE 104 may each include multiple antennas, such as antenna elements, antenna panels and / or antenna arrays, to facilitate beamforming. In some cases, BS 180 may send beamformed signals to UE 104 in one or more transmit directions 182'. UE 104 may receive beamformed signals from BS 180 in one or more receive directions 182". UE 104 may also send beamformed signals to BS 180 in one or more transmit directions 182". BS 180 may also receive beamformed signals from UE 104 in one or more receive directions 182'. BS 180 and UE 104 may then perform beam training to determine the best receive direction and transmit direction for each of BS 180 and UE 104. It is noteworthy that the transmit direction and receive direction of BS 180 may be the same or may be different. Similarly, the transmit direction and receive direction of UE 104 may be the same or may be different.

[0047] Wireless communication network 100 also includes Wi-Fi AP 150 that communicates with Wi-Fi stations (STAs) 152 via communication links 154 in, for example, the 2.4 GHz and / or 5 GHz unlicensed spectrum.

[0048] Certain UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), a physical sidelink control channel (PSCCH), and / or a physical sidelink feedback channel (PSFCH).

[0049] The EPC 160 may include various functional components, including: a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, a multimedia broadcast multicast service (MBMS) gateway 168, a broadcast multicast service center (BM-SC) 170, and / or a packet data network (PDN) gateway 172, such as in the depicted example. The MME 162 may communicate with a home subscriber server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. In general, the MME 162 provides bearer and connection management.

[0050] Generally speaking, user Internet Protocol (IP) packets are delivered through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation and other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176, which may include, for example, the Internet, an Intranet, an IP Multimedia Subsystem (IMS), a Packet Switched (PS) streaming media service, and / or other IP services.

[0051] The BM-SC 170 may provide functionality for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS delivery, may be used to authorize and initiate MBMS bearer services within a public land mobile network (PLMN), and / or may be used to schedule MBMS delivery. The MBMS Gateway 168 may be used to distribute MBMS services to BSs 102 belonging to a multicast broadcast single frequency network (MBSFN) area broadcasting a specific service, and / or may be responsible for session management (start / stop) and for collecting eMBMS related charging information.

[0052] 5GC 190 may include various functional components, including: access and mobility management function (AMF) 192, other AMFs 193, session management function (SMF) 194, and user plane function (UPF) 195. AMF 192 may communicate with unified data management (UDM) 196.

[0053] AMF 192 is a control node that handles signaling between UE 104 and 5GC 190. AMF 192 provides, for example, Quality of Service (QoS) flow and session management.

[0054] Internet Protocol (IP) packets are delivered through UPF 195, which is connected to IP Services 197 and provides UE IP address allocation and other functions for 5GC 190. IP Services 197 may include, for example, the Internet, Intranet, IMS, PS streaming services, and / or other IP services.

[0055] In various aspects, a network entity or network node may be implemented as a converged base station, a decomposed base station, a component of a base station, an integrated access and backhaul (IAB) node, a relay node, a sidelink node, to name a few examples.

[0056] Figure 2 An example disaggregated base station 200 architecture is depicted. The disaggregated base station 200 architecture may include one or more central units (CUs) 210 that may communicate directly with a core network 220 via a backhaul link, or indirectly with the core network 220 through one or more disaggregated base station units, such as a near real-time (near-RT) RAN intelligent controller (RIC) 225 via an E2 link, or a non-real-time (non-RT) RIC 215 associated with a service management and orchestration (SMO) framework 205, or both. The CU 210 may communicate with one or more distributed units (DUs) 230 via respective midhaul links, such as an F1 interface. The DU 230 may communicate with one or more radio units (RUs) 240 via respective fronthaul links. The RU 240 may communicate with respective UEs 104 via one or more radio frequency (RF) access links. In some implementations, a UE 104 may be served simultaneously by multiple RUs 240.

[0057] Each of the units (e.g., CU 210, DU 230, RU 240, and near-RT RIC 225, non-RT RIC 215, and SMO framework 205) may include or be coupled to one or more interfaces configured to receive or send signals, data, or information (collectively referred to as signals) via a wired or wireless transmission medium. Each of the units or an associated processor or controller that provides instructions to the communication interface of the unit may be configured to communicate with one or more of the other units via a transmission medium. For example, the units may include a wired interface configured to receive or send signals to one or more of the other units via a wired transmission medium. Additionally or alternatively, the unit may include a wireless interface that may include a receiver, transmitter, or transceiver (such as a radio frequency (RF) transceiver) configured to receive or send signals, or both, to one or more of the other units on a wireless transmission medium.

[0058] In some aspects, CU 210 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function may be implemented as having an interface configured to communicate signals with other control functions hosted by CU 210. CU210 may be configured to handle user plane functionality (e.g., central unit-user plane (CU-UP)), control plane functionality (e.g., central unit-control plane (CU-CP)), or a combination thereof. In some specific implementations, CU 210 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, CU 210 may be implemented to communicate with DU 230 for network control and signaling.

[0059] DU 230 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RUs 240. In some aspects, DU 230 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc.) at least in part according to a functional split such as those defined by the 3rd Generation Partnership Project (3GPP). In some aspects, DU 230 may also host one or more low PHY layers. Each layer (or module) may be implemented with an interface that is configured to communicate signals with other layers (and modules) hosted by DU 230 or with control functions hosted by CU 210.

[0060] The lower layer functions may be implemented by one or more RUs 240. In some deployments, the RU 240 controlled by the DU 230 may correspond to a logical node that hosts RF processing functions or low PHY layer functions (such as performing fast Fourier transform (FFT), inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, etc.), or both, based at least in part on functional splitting (such as lower layer functional splitting). In such an architecture, the RU 240 may be implemented to handle over-the-air (OTA) communications with one or more UEs 104. In some specific implementations, real-time and non-real-time aspects of control plane and user plane communications with the RU 240 may be controlled by the corresponding DU 230. In some scenarios, this configuration may enable the implementation of the DU 230 and the CU 210 in a cloud-based RAN architecture (such as a vRAN architecture).

[0061] The SMO framework 205 may be configured to support RAN deployment and provisioning of non-virtualized network elements and virtualized network elements. For non-virtualized network elements, the SMO framework 205 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which may be managed via an operation and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO framework 205 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) 290) to perform network element lifecycle management (such as instantiating virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements may include, but are not limited to, CU 210, DU 230, RU 240, and near-RT RIC 225. In some specific implementations, the SMO framework 205 may communicate with hardware aspects of the 4G RAN, such as an open eNB (O-eNB) 211, via the O1 interface. Additionally, in some specific implementations, the SMO framework 205 may communicate directly with one or more RUs 240 via the O1 interface. The SMO framework 205 may also include a non-RT RIC 215 configured to support the functionality of the SMO framework 205 .

[0062] The non-RT RIC 215 may be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence / machine learning (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 225. The non-RT RIC 215 may be coupled to or in communication with the near-RT RIC 225 (such as via an A1 interface). The near-RT RIC 225 may be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions through an interface (such as via an E2 interface) that connects one or more CUs 210, one or more DUs 230, or both, and the O-eNB with the near-RT RIC 225.

[0063] In some implementations, in order to generate an AI / ML model to be deployed in the near-RT RIC 225, the non-RT RIC 215 may receive parameters or external enrichment information from an external server. Such information may be utilized by the near-RT RIC 225 and may be received from a non-network data source or from a network function at the SMO framework 205 or the non-RT RIC 215. In some examples, the non-RT RIC 215 or the near-RT RIC 225 may be configured to tune RAN behavior or performance. For example, the non-RT RIC 215 may monitor long-term trends and patterns of performance and employ AI / ML models to perform corrective actions through the SMO framework 205 (such as via reconfiguration of O1) or via creation of RAN management policies (such as A1 policies).

[0064] Figure 3 Aspects of an example BS 102 and UE 104 are depicted.

[0065] In general, BS 102 includes various processors (e.g., 320, 330, 338, and 340), antennas 334a-334t (collectively 334), transceivers 332a-332t (collectively 332) including modulators and demodulators, and other aspects that enable wireless transmission of data (e.g., data source 312) and wireless reception of data (e.g., data sink 339). For example, BS 102 can transmit and receive data between BS 102 and UE 104. BS 102 includes a controller / processor 340 that can be configured to implement various functions described herein related to wireless communication.

[0066] In general, the UE 104 includes various processors (e.g., 358, 364, 366, and 380), antennas 352a-352r (collectively 352), transceivers 354a-354r (collectively 354) including modulators and demodulators, and other aspects that enable wireless transmission of data (e.g., retrieved from a data source 362) and wireless reception of data (e.g., provided to a data sink 360). The UE 104 includes a controller / processor 380 that can be configured to implement various functions described herein related to wireless communications.

[0067] Regarding example downlink transmissions, BS 102 includes a transmit processor 320 that can receive data from a data source 312 and control information from a controller / processor 340. The control information can be for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical HARQ indicator channel (PHICH), a physical downlink control channel (PDCCH), a group common PDCCH (GC PDCCH), and / or others. In some examples, the data can be for a physical downlink shared channel (PDSCH).

[0068] The transmit processor 320 may process (e.g., encode and symbol map) data and control information to obtain data symbols and control symbols, respectively. The transmit processor 320 may also generate reference symbols, such as for a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a PBCH demodulation reference signal (DMRS), and a channel state information reference signal (CSI-RS).

[0069] The transmit (TX) multiple-input multiple-output (MIMO) processor 330 may perform spatial processing (e.g., pre-coding) on ​​data symbols, control symbols, and / or reference symbols, where applicable, and may provide an output symbol stream to a modulator (MOD) in a transceiver 332a-332t. Each modulator in the transceiver 332a-332t may process a corresponding output symbol stream to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The downlink signals from the modulators in the transceivers 332a-332t may be transmitted via antennas 334a-334t, respectively.

[0070] To receive downlink transmissions, UE 104 includes antennas 352a-352r that can receive downlink signals from BS 102 and can provide received signals to demodulators (DEMODs) in transceivers 354a-354r, respectively. Each demodulator in transceivers 354a-354r can condition (e.g., filter, amplify, downconvert, and digitize) a corresponding received signal to obtain input samples. Each demodulator can further process the input samples to obtain received symbols.

[0071] A MIMO detector 356 may obtain received symbols from all demodulators in transceivers 354a-354r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 358 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 104 to a data sink 360, and provide decoded control information to a controller / processor 380.

[0072] For example uplink transmissions, the UE 104 also includes a transmit processor 364 that can receive and process data from a data source 362 (e.g., for a PUSCH) and control information from a controller / processor 380 (e.g., for a physical uplink control channel (PUCCH)). The transmit processor 364 can also generate reference symbols for reference signals (e.g., for a sounding reference signal (SRS)). The symbols from the transmit processor 364 can be pre-decoded by a TX MIMO processor 366, if applicable, further processed by a modulator in the transceivers 354a-354r (e.g., for SC-FDM), and transmitted to the BS 102.

[0073] At BS 102, uplink signals from UE 104 may be received by antennas 334 a-334 t, processed by demodulators in transceivers 332 a-332 t, detected by MIMO detector 336 if applicable, and further processed by receive processor 338 to obtain decoded data and control information transmitted by UE 104. Receive processor 338 may provide decoded data to data sink 339 and decoded control information to controller / processor 340.

[0074] Memories 342 and 382 may store data and program codes for BS 102 and UE 104, respectively.

[0075] The scheduler 344 may schedule UEs for data transmission on the downlink and / or uplink.

[0076] In various aspects, BS 102 may be described as sending and receiving various types of data associated with the methods described herein. In these contexts, "sending" may refer to various mechanisms for outputting data, such as outputting data from a data source 312, a scheduler 344, a memory 342, a transmit processor 320, a controller / processor 340, a TX MIMO processor 330, a transceiver 332a-332t, an antenna 334a-334t, and / or other aspects described herein. Similarly, "receiving" may refer to various mechanisms for obtaining data, such as obtaining data from an antenna 334a-334t, a transceiver 332a-332t, a RX MIMO detector 336, a controller / processor 340, a receive processor 338, a scheduler 344, a memory 342, and / or other aspects described herein.

[0077] In various aspects, the UE 104 may also be described as sending and receiving various types of data associated with the methods described herein. In these contexts, "sending" may refer to various mechanisms for outputting data, such as outputting data from a data source 362, a memory 382, ​​a transmit processor 364, a controller / processor 380, a TX MIMO processor 366, a transceiver 354a-354t, an antenna 352a-352t, and / or other aspects described herein. Similarly, "receiving" may refer to various mechanisms for obtaining data, such as obtaining data from an antenna 352a-352t, a transceiver 354a-354t, a RX MIMO detector 356, a controller / processor 380, a receive processor 358, a memory 382, ​​and / or other aspects described herein.

[0078] In some aspects, the processor may be configured to perform various operations, such as those associated with the methods described herein, and send (output) data to or receive (obtain) data from another interface configured to send or receive data, respectively.

[0079] Figure 4A , Figure 4B , Figure 4C and Figure 4D Describes a method for use in a wireless communication network such as Figure 1 Various aspects of the data structure of the wireless communication network 100).

[0080] Specifically, Figure 4A is a diagram 400 illustrating an example of a first subframe within a 5G (e.g., 5G NR) frame structure, Figure 4B is a diagram 430 illustrating an example of a DL channel within a 5G subframe, Figure 4C is a diagram 450 illustrating an example of a second subframe within a 5G frame structure, and Figure 4D FIG480 is a diagram illustrating an example of UL channels within a 5G subframe.

[0081] Wireless communication networks can utilize Orthogonal Frequency Division Multiplexing (OFDM) with a Cyclic Prefix (CP) on both the uplink and downlink. Such systems can also support half-duplex operation using Time Division Duplex (TDD). OFDM and Single Carrier Frequency Division Multiplexing (SC-FDM) can be used to maximize the system bandwidth (e.g., Figure 4B and Figure 4D The modulation symbols may be transmitted in the frequency domain using OFDM and / or in the time domain using SC-FDM.

[0082] The wireless communication frame structure may be frequency division duplex (FDD), where for a particular set of subcarriers, subframes within the set of subcarriers are dedicated to either DL or UL. The wireless communication frame structure may also be time division duplex (TDD), where for a particular set of subcarriers, subframes within the set of subcarriers are dedicated to both DL and UL.

[0083] exist Figure 4A and Figure 4C In the wireless communication frame structure, TDD is used, where D is DL, U is UL, and X is used flexibly between DL / UL. The UE can be configured with a time slot format (dynamically configured by DL control information (DCI) or semi-statically / statically configured by radio resource control (RRC) signaling) through the received time slot format indicator (SFI). In the depicted example, the 10ms frame is divided into 10 equally sized 1ms subframes. Each subframe may include one or more time slots. In some examples, each time slot may include 7 or 14 symbols, depending on the time slot format. The subframe may also include micro-time slots, which typically have fewer symbols than the entire time slot. Other wireless communication technologies may have different frame structures and / or different channels.

[0084] In certain aspects, the number of time slots within a subframe is based on the time slot configuration and the parameter set. For example, for time slot configuration 0, different parameter sets (μ) 0 to 5 allow for 1, 2, 4, 8, 16, and 32 time slots per subframe, respectively. For time slot configuration 1, different parameter sets 0 to 2 allow for 2, 4, and 8 time slots per subframe, respectively. Thus, for time slot configuration 0 and parameter set μ, there are 14 symbols / time slot and 2μ time slots / subframe. The subcarrier spacing and symbol length / duration are a function of the parameter set. The subcarrier spacing may be equal to 2 μ × 15kHz, where μ is parameter set 0 to 5. Thus, parameter set μ=0 has a subcarrier spacing of 15kHz, and parameter set μ=5 has a subcarrier spacing of 480kHz. The symbol length / duration is inversely related to the subcarrier spacing. Figure 4A , Figure 4B , Figure 4C and Figure 4D An example is provided for slot configuration 0 with 14 symbols per slot and parameter set μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs.

[0085] like Figure 4A , Figure 4B , Figure 4C and Figure 4DAs depicted in , a resource grid can be used to represent a frame structure. Each time slot includes a resource block (RB) (also called a physical RB (PRB)) extending, for example, 12 consecutive subcarriers. The resource grid is divided into a plurality of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0086] like Figure 4A As illustrated in FIG. , some REs carry data for UEs (eg, Figure 1 and Figure 3 The RS may include a demodulation RS (DMRS) and / or a channel state information reference signal (CSI-RS) for channel estimation at the UE. The RS may also include a beam measurement RS (BRS), a beam refinement RS (BRRS), and / or a phase tracking RS (PT-RS).

[0087] Figure 4B Examples of various DL channels within a subframe of a frame are illustrated.The Physical Downlink Control Channel (PDCCH) carries DCI within one or more Control Channel Elements (CCEs), each CCE comprising, for example, nine RE Groups (REGs), each REG comprising, for example, four consecutive REs in an OFDM symbol.

[0088] The primary synchronization signal (PSS) may be in symbol 2 of a particular subframe of a frame. The PSS is transmitted by a UE (e.g., Figure 1 and Figure 3 104) is used to determine subframe / symbol timing and physical layer identification.

[0089] A Secondary Synchronization Signal (SSS) may be within symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and radio frame timing.

[0090] Based on the physical layer identifier and the physical layer cell identifier group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the location of the aforementioned DMRS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block. The MIB provides the system frame number (SFN) and the number of RBs in the system bandwidth. The physical downlink shared channel (PDSCH) carries user data, broadcast system information (such as system information blocks (SIBs)) that is not sent via the PBCH, and / or paging messages.

[0091] like Figure 4CAs illustrated in , some REs carry DMRS for channel estimation at the base station (indicated as R for one particular configuration, but other DMRS configurations are possible). The UE may send DMRS for PUCCH and DMRS for PUSCH. The PUSCH DMRS may be sent, for example, in the first one or two symbols of the PUSCH. The PUCCH DMRS may be sent in different configurations depending on whether a short PUCCH or a long PUCCH is sent and depending on the specific PUCCH format used. UE 104 may send a sounding reference signal (SRS). The SRS may be sent, for example, in the last symbol of a subframe. The SRS may have a comb structure, and the UE may send the SRS on one of the comb structures in the comb structure. The SRS may be used by the base station for channel quality estimation to achieve frequency-dependent scheduling of the UL.

[0092] Figure 4D Examples of various UL channels within a subframe of a frame are illustrated. The PUCCH may be located at a position as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), and HARQ ACK / NACK feedback. The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0093] Example non-terrestrial network

[0094] Figure 5 An example of a wireless communication network 500 including a non-terrestrial network (NTN) entity 140 (which may generally be referred to as NTN 140) in which aspects of the present disclosure may be practiced is illustrated. In some examples, the wireless communication network 500 may implement aspects of the wireless communication system 100. For example, the wireless communication network 500 may include a BS 102, a UE 104, and a non-terrestrial network entity 140, such as a satellite. In the case of a terrestrial network, the BS 102 may serve a coverage area or cell 110a, and in the case of a non-terrestrial network (NTN), the non-terrestrial network entity 140 may serve a coverage area 110b. Some NTNs may employ airborne platforms (e.g., drones or balloons) and / or spaceborne platforms (e.g., satellites).

[0095] As part of wireless communications in the NTN, the non-terrestrial network entity 140 may communicate with the BS 102 and the UE 104. In the case of a terrestrial network, the UE 104 may communicate with the BS 102 via a communication link 514. In the case of NTN wireless communications, the non-terrestrial network entity 140 may be a serving cell for the UE 104 via a communication link 516. In certain aspects, the non-terrestrial network entity 140 may act as a repeater (or remote radio head) for the BS 102 and the UE 104. For example, the BS 102 may communicate with the non-terrestrial network entity 140 via a communication link 518, and the non-terrestrial network entity may relay signaling between the BS 102 and the UE 104 via the communication links 516, 518.

[0096] Aspects related to the handover between TN and NTN

[0097] As described above, when the UE is connected (RRC_CONNECTED state) and moves within the same radio access technology (RAT), such as in Figure 6 In the example shown in 5G, connection reestablishment occurs when, for example, the UE detects a radio link failure or when a handover procedure fails. If the UE recovers, the UE initiates the connection reestablishment procedure and the target is able to retrieve any pending data from the source using the UE context and forward it to the UE.

[0098] When a UE is connected and moves from one radio access technology (RAT) to another, such as in Figure 7 In the example shown in , the connection reestablishment procedure is generally not supported. In such cases, when the UE is restored in a different RAT, the UE generally gives the reestablishment procedure and enters RRC_IDLE. This is because the target RAT will not have the UE context (e.g., including the UE identity) of the UE.

[0099] like Figure 8 As shown, for some devices, such as non-control plane (CP)-cellular Internet of Things (CIoT) UEs, connection reestablishment may be handled in the radio network. In such cases, if the connection reestablishment is successful, the core network (CN) may not be aware of the connection reestablishment.

[0100] On the other hand, as also illustrated, for CP-CIoT UE, connection reestablishment is handled in the core network. For CP-CIoT UE, there may be no radio network access security. Security can be handled in the core network. Therefore, the core NW handles the security context and related identification, as well as its preservation during reestablishment. In addition, when the connection is reestablished, the CN can forward any pending data packets to the UE.

[0101] In conventional systems, for CP-CIoT UEs, connection reestablishment is still not supported when RAT changes. Typically, different RATs are connected to different core networks, and connection reestablishment across different core NWs is not supported.

[0102] When recovering from RLF, the CP-CIoT UE may transmit an RRC connection reestablishment request message including a UE identity (e.g., a serving temporary mobile subscriber identity (S-TMSI)). Fig. 9 As illustrated in , the S-TMSI may be embedded in (and extracted from) a Globally Unique Temporary Identifier (GUTI). The S-TMSI generally refers to an identifier assigned by the MME that is unique in the MME pool. There may be an indication in the SIB indicating whether RRC connection reestablishment using the S-TMSI is allowed. The MME authenticates the UE based on the security parameters (ul-NAS-MAC and ul-NAS-Count) included in the message.

[0103] As mentioned above, RRC connection reestablishment is generally not supported upon RAT change. However, in some cases, there may be fewer reasons for this lack of support than in conventional systems. For example, in Rel-17, the Internet of Things (IoT) Non-Terrestrial Network (NTN) RAT is specified, which generally defines a satellite access network for IoT devices.

[0104] Although formally defined as another RAT (primarily due to core network aspects such as Quality of Service (QoS), charging, etc.), in some aspects the IoT NTN RAT may not be a truly different RAT.

[0105] Therefore, if Fig.10 As illustrated in , it is possible that the IoT terrestrial network (TN) RAT and the IoT NTN RAT are served by the same core network (i.e., the same evolved packet core (EPC) mobility management entity (MME)). In this case, the conventional reasons for not allowing RRC connection reestablishment for IoT UEs upon RAT change may no longer exist. In other words, the UE context may remain in the same MME or MME pool even when moving between NT and NTN. Therefore, in this case, there seems to be no reason not to allow RRC connection reestablishment for CPICIoT UEs upon RAT change (IoT TN to IoT NTN or vice versa).

[0106] The IoT TN RAT and the IoT NTN RAT can (and likely will) be deployed in different Tracking Areas (TAs) that are not in the same Tracking Area Identity (TAI) list (i.e., Registration Area). This means that the UE may need to perform a TA Update (TAU) when the RAT changes. The MME may assign a new Serving Temporary Mobile User Identity (S-TMSI, sometimes referred to as a shortened TMSI) to the UE in the target RAT, and in such a case one of the potential benefits of reestablishing the Radio Resource Control (RRC) connection may be lost. If the UE identity has changed, the old security context cannot be saved. Any pending data forwarding may still benefit from the connection reestablishment.

[0107] According to aspects of the present disclosure, there are various options on how to allow RRC connection re-establishment of a UE (e.g., a CP CIoT UE) upon RAT change (e.g., from IoT TN to IoT NTN or vice versa).

[0108] For example, according to the first option, the UE may perform RRC connection reestablishment using the old S-TMSI at the time of inter-RAT (IRAT) change from IoT TN to IoT NTN, followed by a TAU request. In such a case, the purpose of the TAU request may be to update the TA list. If the MME is not the same, the (target) RAN may intercept the RRC reestablishment procedure (message) and transmit an RRC connection establishment message to the UE.

[0109] A potential benefit of this approach is that pending data may be forwarded and it may not cause non-access stratum (NAS) layer impact.

[0110] In some cases, the IoT NTN RAN may broadcast a system information block (SIB) indication indicating whether RRC reestablishment using s-TMSI is supported upon RAT change. If reestablishment using s-TMSI is allowed, the UE may be allowed to transmit an RRC connection reestablishment request. In some cases, the UE may attempt RRC reestablishment using s-TMSI only if the UE detects a SIB indicating support for s-TMSI.

[0111] In some cases, upon recovery, the UE may establish a new RRC connection in the target (TN or NTN). In such cases, the UE may transmit a TAU request and use a new code point indicating "handover" for updating the type IE in the TAU REQUEST message. For example, Fig.11 As illustrated in , one of two previously unused code points ("100" and "101") in the Update Type IE in the TAU REQUEST message can be used to indicate a handover or access change (eg, a change from TN to NTN or vice versa).

[0112] Based on the new update type, the MME may check for any pending data for the UE and forward the pending data if found. The MME may identify the UE based on the S-TMSI extracted from the Globally Unique Temporary Identifier (GUTI) received in the TAU REQUEST message (see Fig. 9 ).

[0113] Potential benefits of this method of indicating access changes via a TAU request include that pending data may be forwarded and there may be no RAN impact (eg, no RRC connection re-establishment is required upon RAT change).

[0114] In some cases, if the MME is not the same, the MME may reject the TAU request. In some cases, if the MME is not the same, the MME may accept the TAU request as if it was transmitted with update type "mobility update". In such cases, the pending data may not be forwarded in this case. This is consistent with the conventional (legacy) behavior when unused code points are used for the Update Type IE in the TAU REQUEST message.

[0115] Example Operation of User Equipment

[0116] Fig.12 shows a method for use by a UE such as Figure 1 and Figure 3 Method 1200 for wireless communication with UE 104.

[0117] Method 1200 begins at 1205 by performing a mobility procedure to establish a connection in a target RAT while maintaining a context established in a source RAT, wherein one of the source RAT or the target RAT is a TN RAT and the other is an NTN RAT. In some cases, the operation of this step refers to the Fig.15 The described mobility procedure circuitry may be or may be performed by the mobility procedure circuitry.

[0118] Then, the method 1200 proceeds to step 1210, where a TAU request is transmitted after the connection is established in the target RAT. In some cases, the operation of this step refers to the operation of Fig.15 The described TAU request circuit may be performed by the UE request circuit.

[0119] In some aspects, the UE comprises a CIoT wireless device. In some aspects, the UE performs a mobility procedure after detecting an RLF in the source RAT. In some aspects, performing the mobility procedure comprises performing an RRC connection reestablishment procedure. In some aspects, the method 1200 further comprises: receiving an updated TA list in response to the TAU request. In some aspects, the method 1200 further comprises: receiving an RRC connection establishment message if the target RAT is served by a different CN than the source RAT.

[0120] In some aspects, the RRC connection reestablishment procedure is performed using the S-TMSI.In some aspects, the method 1200 further includes, prior to performing the RRC connection reestablishment procedure using the S-TMSI, receiving a SIB indicating that the target RAT supports RRC connection reestablishment using the S-TMSI.

[0121] In some aspects, the TAU request includes an update type indicating a handover from a source RAT to a target RAT. In some aspects, the update type includes an EPS update type access change.

[0122] In one aspect, method 1200 or any aspect related thereto may be performed by an apparatus such as Fig.15 The method 1200 is performed by a communication device 1500 that includes various components operable to, configured to, or adapted to perform the method 1200. The communication device 1500 is described in more detail below.

[0123] It should be noted that Fig.12 This is merely one example of a method, and other methods including fewer, additional, or alternative steps may be consistent with the present disclosure.

[0124] Example Operations of Network Entities

[0125] Fig.13 shows a method for use by network entities such as Figure 1 and Figure 3 BS102 or as relative to Figure 2 A method 1300 of performing wireless communications with a decomposed base station is discussed.

[0126] Method 1300 begins at 1305 by sending a SIB indicating support for an RRC connection reestablishment procedure for the UE between a target RAT and a source RAT, wherein one of the source RAT or the target RAT is a TN RAT and the other is an NTN RAT. In some cases, the operation of this step refers to the operation described in reference to Fig.16 The described SIB transmission circuit may be or may be performed by the SIB transmission circuit.

[0127] Then, the method 1300 proceeds to step 1310 to participate in the RRC connection reestablishment process with the UE to maintain the context established in the source RAT. In some cases, the operation of this step refers to the following Fig.16 The described RRC connection process circuit may be performed by the RRC connection process circuit.

[0128] In some aspects, the UE comprises a CIoT wireless device. In some aspects, if the target RAT is served by a different CN than the source RAT, the method 1300 further comprises: receiving an RRC reestablishment process message sent by the UE, and sending an RRC connection establishment message to the UE.

[0129] In one aspect, method 1300 or any aspect related thereto may be performed by an apparatus such as Fig.16 The method 1300 is performed by a communication device 1600 that includes various components operable to, configured to, or adapted to perform the method 1300. The communication device 1600 is described in more detail below.

[0130] It should be noted that Fig.13 This is merely one example of a method, and other methods including fewer, additional, or alternative steps may also be consistent with the present disclosure.

[0131] Fig.14 shows a method for use by network entities such as Figure 1 and Figure 3 BS102 or as relative to Figure 2 A method 1400 of performing wireless communications with a decomposed base station is discussed.

[0132] Method 1400 begins at 1405 by engaging in a mobility procedure to transition a UE from a source RAT to a target RAT, wherein one of the source RAT or the target RAT is a TN RAT and the other is an NTN RAT. In some cases, the operation of this step refers to the operation described in reference to Fig.17 The described UE mobility procedure circuitry may be or may be performed by the UE mobility procedure circuitry.

[0133] Then, the method 1400 proceeds to step 1410, where the context of the UE is retrieved from the source RAT. In some cases, the operation of this step refers to the operation described in reference to Fig.17 The described UE context processing circuit may be performed by the UE context processing circuit.

[0134] Then, the method 1400 proceeds to step 1415 to forward the data from the source RAT to the UE. In some cases, the operation of this step refers to the operation of Fig.17 The described data forwarding circuit may be performed by the data forwarding circuit.

[0135] In some aspects, the UE includes a CIoT wireless device. In some aspects, the mobility procedure includes an RRC connection reestablishment procedure. In some aspects, the RRC connection reestablishment procedure is performed using an S-TMSI. In some aspects, the S-TMSI is used to retrieve a context.

[0136] In some aspects, method 1400 further includes: receiving a TAU request sent from the UE. In some aspects, the TAU request includes an update type indicating a handover from a source RAT to a target RAT. In some aspects, the update type includes an EPS update type access change. Some examples of the method, apparatus, non-transitory computer-readable medium, and system further include: extracting the S-TMSI in the TAU request. In some aspects, if the S-TMSI is not found when performing the context retrieval, method 1400 further includes: rejecting the TAU request or performing a backup TAU update with an update type other than the update type indicating the handover.

[0137] In one aspect, method 1400 or any aspect related thereto may be performed by an apparatus such as Fig.17 The method 1400 is performed by a communication device 1700 that includes various components operable to, configured to, or adapted to perform the method 1400. The communication device 1700 is described in more detail below.

[0138] It should be noted that Fig.14 This is merely one example of a method, and other methods including fewer, additional, or alternative steps may also be consistent with the present disclosure.

[0139] Example Communication Device

[0140] Fig.15 Depicted are aspects of an example communications device 1500. In some examples, communications device 1500 is a user equipment (UE), such as described above with respect to Figure 1 and Figure 3 UE 104 is described.

[0141] The communication device 1500 includes a processing system 1505 coupled to a transceiver 1565 (e.g., a transmitter and / or a receiver). The transceiver 1565 is configured to transmit and receive signals of the communication device 1500, such as various signals as described herein, via an antenna 1570. The processing system 1505 may be configured to perform processing functions of the communication device 1500, including processing signals received and / or to be transmitted by the communication device 1500.

[0142] The processing system 1505 may include one or more processors 1510. In various aspects, the one or more processors 1510 may represent one or more of the receive processor 358, the transmit processor 364, the TX MIMO processor 366, and / or the controller / processor 380, as described with respect to FIG. Figure 3The one or more processors 1510 are coupled to the computer readable medium / memory 1535 via the bus 1560. In some aspects, the computer readable medium / memory 1535 is configured to store instructions (e.g., computer executable code) that, when executed by the one or more processors 1510, cause the one or more processors 1510 to perform operations related to Fig.12 The described method 1200 or any aspect related thereto. It should be noted that references to a processor performing a function of the communication device 1500 may include one or more processors 1510 performing that function of the communication device 1500.

[0143] In the depicted example, the computer readable medium / memory 1535 stores codes (e.g., executable instructions) such as mobility procedure code 1540, TAU request code 1545, TA list management code 1550, and RRC connection management code 1555. Processing of the mobility procedure code 1540, TAU request code 1545, TA list management code 1550, and RRC connection management code 1555 may enable the communication device 1500 to perform operations with respect to the communication device 1500. Fig.12 The described method 1200 or any aspect related thereto.

[0144] The one or more processors 1510 include circuits configured to implement (e.g., execute) code stored in the computer-readable medium / memory 1535, including circuits such as mobility process circuits 1515, TAU request circuits 1520, TA list management circuits 1525, and RRC connection management circuits 1530. Processing using the mobility process circuits 1515, TAU request circuits 1520, TA list management circuits 1525, and RRC connection management circuits 1530 may enable the communication device 1500 to perform operations with respect to Fig.12 The described method 1200 or any aspect related thereto.

[0145] The various components of the communication device 1500 may be provided for performing Fig.12 The described means of method 1200 or any aspect thereof. For example, means for sending, transmitting, or outputting for sending may include Figure 3 The transceiver 354 and / or antenna 352 of the UE 104 illustrated in FIG. 1 , and / or Fig.15 The transceiver 1565 and antenna 1570 of the communication device 1500 in FIG. 1 may include Figure 3 The transceiver 354 and / or antenna 352 and / or Fig.15 The transceiver 1565 and antenna 1570 of the communication device 1500.

[0146] According to some aspects, the mobility procedure circuitry 1515 performs a mobility procedure to establish a connection in a target RAT while maintaining a context established in a source RAT, wherein one of the source RAT or the target RAT is a TN RAT and the other is an NTN RAT. According to some aspects, the TAU request circuitry 1520 transmits a TAU request after establishing the connection in the target RAT.

[0147] In some aspects, the UE comprises a CIoT wireless device. In some aspects, the UE performs a mobility procedure after detecting RLF in a source RAT. In some aspects, performing the mobility procedure comprises performing an RRC connection reestablishment procedure.

[0148] According to some aspects, the TA list management circuit 1525 receives an updated TA list in response to a TAU request.

[0149] According to some aspects, if the target RAT is served by a different CN than the source RAT, the RRC connection management circuit 1530 receives an RRC connection establishment message. In some aspects, the RRC connection reestablishment procedure is performed using the S-TMSI. In some examples, the RRC connection management circuit 1530 receives a SIB indicating that the target RAT supports RRC connection reestablishment using the S-TMSI before performing the RRC connection reestablishment procedure using the S-TMSI. In some aspects, the TAU request includes an update type indicating a handover from the source RAT to the target RAT. In some aspects, the update type includes an EPS update type access change.

[0150] Fig.16 Aspects of an example communications device 1600 are depicted. In some aspects, communications device 1600 is a network entity such as Figure 1 and Figure 3 BS102 or as relative to Figure 2 The decomposed base station in question.

[0151] The communication device 1600 includes a processing system 1605 coupled to a transceiver 1645 (e.g., a transmitter and / or a receiver) and / or a network interface 1655. The transceiver 1645 is configured to transmit and receive signals for the communication device 1600 via an antenna 1650, such as the various signals described herein. The network interface 1655 is configured to transmit and receive signals for the communication device 1600 via a communication link (such as the various signals described herein with respect to Figure 2 The processing system 1605 may be configured to perform the processing functions of the communication device 1600, including processing signals received by the communication device 1600 and / or to be transmitted.

[0152] The processing system 1605 may include one or more processors 1610. In various aspects, the one or more processors 1610 may represent one or more of the receive processor 338, the transmit processor 320, the TX MIMO processor 330, and / or the controller / processor 340, as described with respect to FIG. Figure 3 The one or more processors 1610 are coupled to the computer readable medium / memory 1625 via the bus 1640. In some aspects, the computer readable medium / memory 1625 is configured to store instructions (e.g., computer executable code) that, when executed by the one or more processors 1610, cause the one or more processors 1610 to perform operations related to Fig.13 The described method 1300 or any aspect related thereto. It should be noted that reference to a processor of the communication device 1600 performing a function may include one or more processors 1610 of the communication device 1600 performing the function.

[0153] In the depicted example, the computer readable medium / memory 1625 stores code (e.g., executable instructions) such as SIB transmission code 1630 and RRC connection procedure code 1635. Processing of the SIB transmission code 1630 and the RRC connection procedure code 1635 may cause the communication device 1600 to perform operations with respect to Fig.13 The described method 1300 or any aspect related thereto.

[0154] The one or more processors 1610 include circuits configured to implement (e.g., execute) code stored in the computer-readable medium / memory 1625, including circuits such as SIB transmission circuitry 1615 and RRC connection process circuitry 1620. Processing performed by the SIB transmission circuitry 1615 and the RRC connection process circuitry 1620 may cause the communication device 1600 to perform operations such as those described above with respect to Fig.13 The described method 1300 or any aspect related thereto.

[0155] The various components of the communication device 1600 may be provided for performing Fig.13 Means for sending, transmitting, or outputting for sending may include: Figure 3 The transceiver 332 and / or antenna 334 and / or Fig.16 The transceiver 1645 and antenna 1650 of the communication device 1600 in FIG. 1 may include Figure 3 The transceiver 332 and / or antenna 334 and / or Fig.16 The transceiver 1645 and antenna 1650 of the communication device 1600 in FIG.

[0156] According to some aspects, the SIB transmission circuit 1615 transmits a SIB indicating support for an RRC connection reestablishment procedure for the UE between a target RAT and a source RAT, wherein one of the source RAT or the target RAT is a TN RAT and the other is an NTN RAT. According to some aspects, the RRC connection procedure circuit 1620 participates in an RRC connection reestablishment procedure with the UE to maintain a context established in the source RAT.

[0157] In some aspects, the UE comprises a CIoT wireless device. In some examples, if the target RAT is served by a different CN than the source RAT, the RRC connection procedure circuit 1620 receives an RRC reestablishment procedure message sent by the UE and sends an RRC connection establishment message to the UE.

[0158] Fig.17 Aspects of an example communications device 1700 are depicted. In some aspects, communications device 1700 is a network entity such as Figure 1 and Figure 3 BS102 or as relative to Figure 2 The decomposed base station in question.

[0159] The communication device 1700 includes a processing system 1705 coupled to a transceiver 1765 (e.g., a transmitter and / or a receiver) and / or a network interface 1775. The transceiver 1765 is configured to transmit and receive signals for the communication device 1700 via an antenna 1770, such as the various signals described herein. The network interface 1775 is configured to transmit and receive signals for the communication device 1700 via a communication link (e.g., the various signals described herein with respect to Figure 2 The processing system 1705 may be configured to perform the processing functions of the communication device 1700, including processing signals received by the communication device 1700 and / or to be transmitted.

[0160] The processing system 1705 includes one or more processors 1710. In various aspects, the one or more processors 1710 may represent one or more of the receive processor 338, the transmit processor 320, the TX MIMO processor 330, and / or the controller / processor 340, as described with respect to FIG. Figure 3 The one or more processors 1710 are coupled to the computer readable medium / memory 1735 via the bus 1760. In some aspects, the computer readable medium / memory 1735 is configured to store instructions (e.g., computer executable code) that, when executed by the one or more processors 1710, cause the one or more processors 1710 to perform operations related to Fig.14The described method 1400 or any aspect related thereto. It should be noted that reference to a processor of the communication device 1700 performing a function may include one or more processors 1710 of the communication device 1700 performing the function.

[0161] In the depicted example, the computer readable medium / memory 1735 stores codes (e.g., executable instructions) such as UE mobility procedure code 1740, UE context processing code 1745, data forwarding code 1750, and TAU request processing code 1755. Processing of the UE mobility procedure code 1740, the UE context processing code 1745, the data forwarding code 1750, and the TAU request processing code 1755 may cause the communication device 1700 to perform operations with respect to the communication device 1700. Fig.14 The described method 1400 or any aspect related thereto.

[0162] The one or more processors 1710 include circuits configured to implement (e.g., execute) code stored in the computer-readable medium / memory 1735, including circuits such as UE mobility process circuits 1715, UE context processing circuits 1720, data forwarding circuits 1725, and TAU request processing circuits 1730. Processing using the UE mobility process circuits 1715, UE context processing circuits 1720, data forwarding circuits 1725, and TAU request processing circuits 1730 may cause the communication device 1700 to perform operations such as those described above with respect to FIG. Fig.14 The described method 1400 or any aspect related thereto.

[0163] The various components of the communication device 1700 may be provided for performing Fig.14 Means for sending, transmitting, or outputting for sending may include: Figure 3 The transceiver 332 and / or antenna 334 and / or Fig.17 The transceiver 1765 and antenna 1770 of the communication device 1700 in FIG. 1 may include Figure 3 The transceiver 332 and / or antenna 334 and / or Fig.17 The transceiver 1765 and antenna 1770 of the communication device 1700.

[0164] According to some aspects, the UE mobility procedure circuit 1715 participates in a mobility procedure to transition the UE from a source RAT to a target RAT, wherein one of the source RAT or the target RAT is a TN RAT and the other is an NTN RAT. According to some aspects, the UE context processing circuit 1720 retrieves the context of the UE from the source RAT. According to some aspects, the data forwarding circuit 1725 forwards data from the source RAT to the UE.

[0165] In some aspects, the UE includes a CIoT wireless device. In some aspects, the mobility procedure includes an RRC connection reestablishment procedure. In some aspects, the RRC connection reestablishment procedure is performed using an S-TMSI. In some aspects, the S-TMSI is used to retrieve a context.

[0166] In accordance with some aspects, the TAU request processing circuitry 1730 receives a TAU request sent from a UE. In some aspects, the TAU request includes an update type indicating a handover from a source RAT to a target RAT. In some aspects, the update type includes an EPS update type access change. In some examples, the TAU request processing circuitry 1730 extracts an S-TMSI from the TAU request. In some examples, if the S-TMSI is not found when performing a context retrieval, the TAU request processing circuitry 1730 rejects the TAU request or performs a backup TAU update with an update type other than the update type indicating a handover.

[0167] Sample Clauses

[0168] Specific implementation examples are described in the following numbered clauses:

[0169] Clause 1: A method of wireless communications by a UE, the method comprising: performing a mobility procedure to establish a connection in a target RAT while maintaining a context established in a source RAT, wherein one of the source RAT or the target RAT is a TN RAT and the other is an NTN RAT; and transmitting a TAU request after establishing the connection in the target RAT.

[0170] Clause 2: The method of clause 1, wherein the UE comprises a CIoT wireless device.

[0171] Clause 3: A method as described in any of clauses 1 and 2, wherein the UE performs the mobility procedure after detecting RLF in the source RAT.

[0172] Clause 4: A method as described in any of clauses 1 to 3, wherein performing the mobility procedure includes performing an RRC connection reestablishment procedure.

[0173] Clause 5: The method of clause 4, further comprising: receiving an updated TA list in response to the TAU request.

[0174] Clause 6: A method as described in clause 4, the method further comprising: if the target RAT is served by a different CN than the source RAT, receiving an RRC connection establishment message.

[0175] Clause 7: A method as described in clause 4, wherein the RRC connection reestablishment procedure is performed using S-TMSI.

[0176] Clause 8: A method according to clause 7, the method further comprising: before performing the RRC connection reestablishment procedure using the S-TMSI, receiving a SIB indicating that the target RAT supports the RRC connection reestablishment using the S-TMSI.

[0177] Clause 9: A method as set out in any of clauses 1 to 8, wherein the TAU request comprises an update type indicating a handover from the source RAT to the target RAT.

[0178] Clause 10: The method of clause 9, wherein the update type comprises EPS update type access change.

[0179] Clause 11: A method of wireless communications by a network entity, the method comprising: sending a SIB indicating support for an RRC connection reestablishment procedure for a UE between a target RAT and a source RAT, wherein one of the source RAT or the target RAT is a TN RAT and the other is an NTN RAT; and participating in the RRC connection reestablishment procedure with the UE to maintain a context established in the source RAT.

[0180] Clause 12: The method of clause 11, wherein the UE comprises a CIoT wireless device.

[0181] Clause 13: A method according to any one of clauses 11 and 12, the method further comprising, if the target RAT is served by a CN different from the source RAT, receiving an RRC reestablishment process message sent by the UE; and sending an RRC connection establishment message to the UE.

[0182] Clause 14: A method of wireless communications by a network entity, the method comprising: engaging in a mobility procedure to transition a UE from a source RAT to a target RAT, wherein one of the source RAT or the target RAT is a TN RAT and the other is an NTN RAT; retrieving a context of the UE from the source RAT; and forwarding data from the source RAT to the UE.

[0183] Clause 15: The method of clause 14, wherein the UE comprises a CIoT wireless device.

[0184] Clause 16: A method as described in any of clauses 14 and 15, wherein the mobility procedure comprises an RRC connection re-establishment procedure.

[0185] Clause 17: A method as described in clause 16, wherein the RRC connection reestablishment procedure is performed using S-TMSI.

[0186] Clause 18: A method as described in clause 17, wherein the S-TMSI is used to retrieve the context.

[0187] Clause 19: The method of clause 16, further comprising: receiving a TAU request sent from the UE.

[0188] Clause 20: The method of clause 19, wherein the TAU request includes an update type indicating a handover from the source RAT to the target RAT.

[0189] Clause 21: The method of clause 20, wherein the update type comprises EPS update type access change.

[0190] Clause 22: The method of clause 20, further comprising: extracting the S-TMSI in the TAU request.

[0191] Clause 23: A method according to clause 22, the method further comprising, if the S-TMSI is not found when performing the context retrieval, rejecting the TAU request or performing a backup TAU update having an update type other than the update type indicating the handover.

[0192] Clause 24: A processing system, the processing system comprising: a memory, the memory comprising computer-executable instructions; one or more processors, the one or more processors configured to execute the computer-executable instructions and cause the processing system to perform the method according to any one of clauses 1 to 23.

[0193] Clause 25: A processing system comprising means for performing the method according to any one of clauses 1 to 23.

[0194] Clause 26: A non-transitory computer readable medium comprising computer executable instructions that, when executed by one or more processors of a processing system, cause the processing system to perform the method of any one of clauses 1 to 23.

[0195] Clause 27: A computer program product embodied on a computer readable storage medium, the computer readable storage medium comprising code for performing the method according to any one of clauses 1 to 23.

[0196] Additional considerations

[0197] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. The examples discussed herein are not limited to the scope, applicability or aspects set forth in the claims. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. For example, without departing from the scope of the present disclosure, the functions and arrangements of the elements discussed may be changed. Each example may omit, replace or add various processes or components as appropriate. For example, the described method may be performed in a different order than the described order, and various actions may be added, omitted or combined. In addition, the features described for some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement a device or practice method. In addition, the scope of the present disclosure is intended to cover such devices or methods practiced using other structures, functionality, or structures and functionality other than the various aspects of the present disclosure set forth herein or different from the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of the present invention.

[0198] The various illustrative logical blocks, modules, and circuits described in conjunction with the present disclosure may be implemented or performed using a general purpose processor, a digital signal processor (DSP), an ASIC, a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in an alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, a system on a chip (SoC), or any other such configuration.

[0199] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items (including single members). For example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0200] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, a database, or another data structure), ascertaining, and the like. Also, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Furthermore, "determining" may include resolving, selecting, choosing, establishing, and the like.

[0201] The method disclosed herein includes one or more actions for implementing the method. The method actions can be interchangeable with each other without departing from the scope of the claims. In other words, unless a specific order of actions is specified, the order and / or use of specific actions can be modified without departing from the scope of the claims. In addition, the various operations of the method described above can be performed by any suitable component that can perform the corresponding function. The component may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs) or processors.

[0202] The following claims are not intended to be limited to the various aspects shown herein, but should be given the full scope consistent with the language of the claims. Within the claims, unless otherwise specified, reference to an element in the singular form is not intended to mean "one and only one", but "one or more". Unless otherwise specified, the term "some" refers to one or more. Any claim element is not interpreted according to the provisions of 35 U.S.C. § 112 (f) unless the element is explicitly stated using the phrase "member for...". All structural and functional equivalents of the elements of the various aspects described throughout the present disclosure that are known or will be known later to a person of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is explicitly stated in the claims.

Claims

1. A method for wireless communication by a user equipment (UE), the method comprising: performing a mobility procedure to establish a connection in a target radio access technology (RAT) while maintaining a context established in a source RAT, wherein one of the source RAT or the target RAT is a terrestrial network (TN) RAT and the other is a non-terrestrial network (NTN) RAT; and A tracking area update (TAU) request is transmitted after establishing the connection in the target RAT.

2. The method of claim 1, wherein the UE comprises a Cellular Internet of Things (CIoT) wireless device. 3 . The method of claim 1 , wherein the UE performs the mobility procedure after detecting a radio link failure (RLF) in the source RAT.

4. The method of claim 1, wherein performing the mobility procedure comprises performing a radio resource control (RRC) connection reestablishment procedure.

5. The method according to claim 4, further comprising: An updated TA list is received in response to the TAU request.

6. The method according to claim 4, further comprising: If the target RAT is served by a core network (CN) different from the source RAT, an RRC connection establishment message is received.

7. The method of claim 4, wherein the RRC connection reestablishment procedure is performed using a Serving Temporary Mobile Subscriber Identity (S-TMSI).

8. The method according to claim 7, further comprising: Prior to performing the RRC connection reestablishment procedure using the S-TMSI, a system information block (SIB) is received indicating that the target RAT supports the RRC connection reestablishment using the S-TMSI.

9. The method of claim 1, wherein the TAU request includes an update type indicating a handover from the source RAT to the target RAT.

10. The method of claim 9, wherein the update type comprises an Evolved Packet System (EPS) update type access change.

11. A method for wireless communication by a network entity, the method comprising: sending a system information block (SIB) indicating support for a radio resource control (RRC) connection reestablishment procedure for a user equipment (UE) between a target radio access technology (RAT) and a source RAT, wherein one of the source RAT or the target RAT is a terrestrial network (TN) RAT and the other is a non-terrestrial network (NTN) RAT; as well as Participate in the RRC connection reestablishment procedure with the UE to maintain the context established in the source RAT.

12. The method of claim 11, wherein the UE comprises a Cellular Internet of Things (CIoT) wireless device.

13. The method of claim 11, further comprising, if the target RAT is served by a core network (CN) different from the source RAT: receiving an RRC reestablishment process message sent by the UE; and Send an RRC connection establishment message to the UE.

14. A method for wireless communication by a network entity, the method comprising: engaging in a mobility procedure to transition a user equipment (UE) from a source radio access technology (RAT) to a target RAT, wherein one of the source RAT or the target RAT is a terrestrial network (TN) RAT and the other is a non-terrestrial network (NTN) RAT; retrieving a context for the UE from the source RAT; and Data is forwarded from the source RAT to the UE.

15. The method of claim 14, wherein the UE comprises a Cellular Internet of Things (CIoT) wireless device.

16. The method of claim 14, wherein the mobility procedure comprises a Radio Resource Control (RRC) connection reestablishment procedure.

17. The method of claim 16, wherein the RRC connection reestablishment procedure is performed using a Serving Temporary Mobile Subscriber Identity (S-TMSI).

18. The method of claim 17, wherein the S-TMSI is used to retrieve the context.

19. The method according to claim 16, further comprising: A tracking area update (TAU) request is received from the UE.

20. The method of claim 19, wherein the TAU request includes an update type indicating a handover from the source RAT to the target RAT.

21. The method of claim 20, wherein the update type comprises an Evolved Packet System (EPS) update type access change.

22. The method according to claim 20, further comprising: A serving temporary mobile subscriber identity (S-TMSI) in the TAU request is extracted.

23. The method of claim 22, further comprising, if the S-TMSI is not found when performing context retrieval, then: and rejecting the TAU request or performing a backup TAU update having an update type other than the update type indicating the handover.

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