Optimization of inter-access and mobility management function mobility

Abstract

The invention relates to a method and an apparatus for optimizing mobility between AMFs. The apparatus initiates a connection establishment with a second network to initiate a network change from the first network to the second network. The apparatus sends a registration request including a mobility registration indication to the second network in response to initiation of the network change. The apparatus sends an identification indication to the second network in response to an identification request from the second network in response to the registration request. The apparatus receives a registration acceptance indication from the second network in response to the transmission of the identification indication. The apparatus sends, to the second network, a PDU session setup request indicating an existing PDU session from the first network for use on the second network.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of Greek Patent Application Serial No. 20220101016, filed on December 8, 2022, entitled "OPTIMIZATION OF INTER - ACCESS AND MOBILITY MANAGEMENT FUNCTION MOBILITY", which is hereby incorporated by reference in its entirety. Technical field

[0003] The present disclosure generally relates to communication systems and, more particularly, to configurations for optimizing inter - access and mobility management function (AMF) mobility. Background art

[0004] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasting. A typical wireless communication system may employ a multiple access technology that is capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single - carrier frequency division multiple access (SC - FDMA) systems, and time - division synchronous code division multiple access (TD - SCDMA) systems.

[0005] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at the urban, national, regional, and even global levels. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continuous mobile broadband evolution promulgated by the Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., related to the Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine - type communication (mMTC), and ultra - reliable low - latency communication (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. Further improvements to 5G NR technology are needed. In addition, these improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies. Summary of the invention

[0006] A simplified summary of one or more aspects is presented below to provide a basic understanding of these aspects. This summary of the invention is not an extensive review of all contemplated aspects. This summary of the invention neither identifies key or critical elements of all aspects nor describes the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0007] In one aspect of the present disclosure, a method, a computer-readable medium, and a device are provided. The device may be a device at a UE. The device may be a processor and / or a modem at the UE or the UE itself. The device initiates a connection establishment with a second network to initiate a network change from a first network to the second network. The device sends a registration request including a mobility registration indication to the second network in response to the initiation of the network change. The device sends an identity indication to the second network in response to an identity request from the second network in response to the registration request. The device receives a registration acceptance indication from the second network in response to the sending of the identity indication. The device sends a PDU session establishment request indicating an existing packet data unit (PDU) session from the first network for use on the second network to the second network.

[0008] In one aspect of the present disclosure, a method, a computer-readable medium, and a device are provided. The device may be a device at a network entity. The device may be a processor and / or a modem at the network entity or the network entity itself. The device obtains a request to initiate a connection establishment with a user equipment (UE) to initiate a network change from a first network to a second network, wherein the network entity is associated with the second network. The device obtains a registration request including a mobility registration indication from the UE in response to the initiation of the network change. The device obtains an identity indication from the UE in response to an identity request provided to the UE in response to the registration request. The device provides a registration acceptance indication to the UE in response to the sending of the identity indication. The device obtains a PDU session establishment request indicating an existing packet data unit (PDU) session from the first network for use on the second network from the UE.

[0009] To achieve the foregoing and related purposes, one or more aspects include the features described comprehensively below and particularly pointed out in the claims. The following description and the drawings set forth in detail some illustrative features of one or more aspects. However, these features indicate only some of the various ways in which the principles of the various aspects may be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0011] Figure 2AIs a diagram illustrating an example of a first frame according to various aspects of the present disclosure.

[0012] Figure 2B Is a diagram illustrating an example of a downlink (DL) channel within a subframe according to various aspects of the present disclosure.

[0013] Figure 2C Is a diagram illustrating an example of a second frame according to various aspects of the present disclosure.

[0014] Figure 2D Is a diagram illustrating an example of an uplink (UL) channel within a subframe according to various aspects of the present disclosure.

[0015] Figure 3 Is a diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0016] Figure 4A Is a diagram illustrating an example of a network in which an interface between AMFs (N14) is deployed.

[0017] Figure 4B Is a diagram illustrating an example of a network in which an interface between AMFs (N14) is not deployed.

[0018] Figure 5 Is a diagram illustrating an example of a call flow in which an interface between AMFs is not deployed.

[0019] Figure 6 Is a diagram illustrating an example of a call flow in which an interface between AMFs is deployed according to various aspects of the present disclosure.

[0020] Figure 7 Is a diagram illustrating an example of a GUTI.

[0021] Figure 8 Is a diagram illustrating an example of a call flow in which an interface between AMFs is deployed according to various aspects of the present disclosure.

[0022] Figure 9 Is a call flow diagram of signaling between a UE and a network entity.

[0023] Figure 10 Is a flowchart of a method of wireless communication.

[0024] Figure 11 Is a flowchart of a method of wireless communication.

[0025] Figure 12 Is a diagram illustrating an example of a hardware implementation for an example apparatus and / or network entity.

[0026] Figure 13 Is a flowchart of a method of wireless communication.

[0027] Figure 14 is a flowchart of a method of wireless communication.

[0028] Figure 15 is a diagram illustrating an example of a hardware implementation for exemplifying a network entity. Detailed Description

[0029] In a wireless communication system (such as in a millimeter wave (mmW) stand-alone system), different networks operating in different frequency ranges (e.g., FR1, FR2) may utilize hardware from different vendors. In a case where different networks operating in different frequency ranges are using hardware from different vendors, an inter-AMF interface (e.g., N14) may not be deployed. In a case where the inter-AMF interface is not deployed, seamless mobility may not be possible. For example, when switching from a first network to a second network, a UE may not be able to use handover and may only use redirection. To overcome such a situation, when switching from a first network to a second network, the UE may provide an identity indication to the second network. The identity indication may allow the second network to identify the UE to allow an existing PDU session utilized on the first network to be utilized on the second network.

[0030] Aspects generally relate to optimization of inter-AMF mobility. Some aspects more particularly relate to a configuration that allows support for an inter-AMF interface in a case where hardware from different vendors is used at least for AMFs between different networks. In some examples, a UE may provide identity information related to the UE to allow establishment of an existing PDU session used on an existing network on a new network. For example, the UE may be connected to a first network and may initiate a network change to a second network such that an existing PDU session from the first network may be used by the UE on the second network.

[0031] At least one advantage of the present disclosure is that a UE switching from a first network to a second network may utilize an existing PDU session utilized on the first network when switching to the second network. Using an existing PDU session on the second network or a newly connected network may allow the UE to maintain services utilizing the existing PDU session and not experience any service interruption.

[0032] The detailed description set forth below in connection with the accompanying drawings is a description of various configurations and does not represent the only configurations in which the concepts described herein may be practiced. To provide a thorough understanding of the various concepts, the detailed description includes specific details. However, the concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0033] Various aspects of a telecommunications system are presented with reference to various apparatuses and methods. These apparatuses and methods are described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the particular application and the design constraints imposed on the overall system.

[0034] As an example, an element, or any portion of an element, or any combination of elements can be implemented as a "processing system" that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, system on a chip (SoC), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. One or more processors in the processing system can execute software. Software should be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, processes, functions, or any combination thereof, regardless of whether it is referred to as software, firmware, middleware, microcode, hardware description language, or other terms.

[0035] Thus, in one or more example aspects, embodiments, and / or use cases, the described functionality can be implemented in hardware, software, or any combination thereof. If implemented in software, the functionality can be stored or encoded on a computer-readable medium as one or more instructions or code. A computer-readable medium includes computer storage media. Storage media can be any available media that can be accessed by a computer. By way of example, such computer-readable media can include random access memory (RAM), read only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of these types of computer-readable media, or any other media capable of storing computer-executable code in the form of instructions or data structures that can be accessed by a computer.

[0036] Although aspects, embodiments, and / or use cases are described by way of illustration of some examples in this application, additional or different aspects, embodiments, and use cases may arise in many different arrangements and scenarios. The aspects, embodiments, and / or use cases described herein may be implemented across many different platform types, devices, systems, shapes, sizes, and packaging arrangements. For example, the aspects, embodiments, and / or use cases may be implemented via integrated chips and other devices based on non-module components (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchase devices, medical devices, artificial intelligence (AI)-enabled devices, etc.). Although some examples may or may not be specifically targeted at use cases or applications, the described examples may have wide applicability. The aspects, embodiments, and / or use cases may range from chip-level or modular components to non-modular, non-chip-level embodiments, and further to aggregated, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more of the technologies herein. In some practical settings, devices incorporating the described aspects and features may also include additional components and features for implementing and practicing the claimed and described aspects. For example, the transmission and reception of wireless signals necessarily includes multiple components for analog and digital purposes (e.g., hardware components including antennas, RF chains, power amplifiers, modulators, buffers, processors, interleavers, adders / summers, etc.). The technologies described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, aggregated components, or disaggregated components, end-user devices, etc., of various sizes, shapes, and configurations.

[0037] The deployment of a communication system (such as a 5G NR system) can be arranged with various components or constituent parts in a variety of ways. In a 5G NR system or network, network nodes, network entities, mobility elements of the network, radio access network (RAN) nodes, core network nodes, network elements, or network equipment (such as a base station (BS)) or one or more units (or one or more components) performing base station functionality may be implemented in an aggregated or disaggregated architecture. For example, a BS (such as a Node B (NB), evolved NB (eNB), NR BS, 5G NB, access point (AP), transmit receive point (TRP), or cell, etc.) may be implemented as an aggregated base station (also referred to as a stand-alone BS or monolithic BS) or a disaggregated base station.

[0038] A converged base station may be configured to utilize a radio protocol stack that is physically or logically integrated within a single RAN node. A split base station may be configured to utilize a protocol stack that is physically or logically distributed across two or more units, such as one or more central or centralized units (CUs), one or more distributed units (DUs), or one or more radio units (RUs). In some aspects, a CU may be implemented within a RAN node and one or more DUs may be co-located with the CU, or alternatively, may be geographically or virtually distributed across one or more other RAN nodes. A DU may be implemented to communicate with one or more RUs. Each of the CU, DU, and RU may be implemented as a virtual unit, i.e., a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU).

[0039] Base station operation or network design may consider the converged characteristics of base station functionality. For example, a split base station may be used in an integrated access backhaul (IAB) network, an open radio access network (O-RAN, such as a network configuration as initiated by the O-RAN Alliance), or a virtualized radio access network (vRAN, also referred to as a cloud radio access network (C-RAN)). Splitting may include distributing functionality across two or more units at various physical locations, as well as virtually distributing the functionality of at least one unit, which may enable flexibility in network design. The various units of a split base station or a split RAN architecture may be configured for wired or wireless communication with at least one other unit.

[0040] Figure 1 FIG. 100 is a diagram illustrating an example of a wireless communication system and an access network. The illustrated wireless communication system includes a split base station architecture. The split base station architecture may include one or more CUs 110, which may communicate directly with a core network 120 via a backhaul link, or indirectly with the core network 120 through one or more split base station units, such as a near real-time (near RT) RAN intelligent controller (RIC) 125 via an E2 link, or a non-real-time (non RT) RIC 115 associated with a service management and orchestration (SMO) framework 105, or both. The CU 110 may communicate with one or more DUs 130 via a respective midhaul link, such as an F1 interface. The DU 130 may communicate with one or more RUs 140 via a respective fronthaul link. The RU 140 may communicate with a respective UE 104 via one or more radio frequency (RF) access links. In some embodiments, the UE 104 may be served simultaneously by multiple RUs 140.

[0041] Each of these units (i.e., CU 110, DU 130, RU 140, and the near RT RIC 125, non-RT RIC 115, and SMO framework 105) may include one or more interfaces or be coupled to one or more interfaces that are configured to receive or transmit signals, data, or information (collectively referred to as signals) via a wired or wireless transmission medium. Each of these units, or an associated processor or controller that provides instructions to the communication interfaces of these units, may be configured to communicate with one or more of the other units via the transmission medium. For example, these units may include a wired interface that is configured to receive signals or transmit signals to one or more of the other units via a wired transmission medium. Additionally, these units may include a wireless interface that may include a receiver, transmitter, or transceiver (such as an RF transceiver) that is configured to receive and / or transmit signals to one or more of the other units via a wireless transmission medium.

[0042] In some aspects, CU 110 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), or service data adaptation protocol (SDAP), etc. Each control function may utilize an interface that is configured to communicate signals with other control functions hosted by CU 110. CU 110 may be configured to handle user plane functionality (i.e., Central Unit - User Plane (CU-UP)), control plane functionality (i.e., Central Unit - Control Plane (CU-CP)), or a combination thereof. In some embodiments, CU 110 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 units may communicate bidirectionally with the CU-CP units via an interface (such as an E1 interface). As needed, CU 110 may be implemented to communicate with DU 130 for network control and signaling.

[0043] DU 130 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RUs 140. In some aspects, DU 130 may host one or more of the radio link control (RLC) layer, media 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 partially according to a functional split (such as those defined by 3GPP). In some aspects, DU 130 may also host one or more low PHY layers. Each layer (or module) may utilize an interface that is configured to communicate signals with other layers (and modules) hosted by DU 130 or with control functions hosted by CU 110.

[0044] The lower layer functionality can be implemented by one or more RUs 140. In some deployments, the RU 140 controlled by the DU 130 can 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, or physical random access channel (PRACH) extraction and filtering, etc.) or both, at least in part based on function splitting (such as lower layer function splitting). In such an architecture, the RU 140 can be implemented to handle over-the-air (OTA) communication with one or more UEs 104. In some embodiments, the real-time and non-real-time aspects of the control plane communication and user plane communication with the RU 140 can be controlled by the corresponding DU 130. In some scenarios, this configuration can enable the DU 130 and CU 110 to be implemented in a cloud-based RAN architecture (such as a vRAN architecture).

[0045] The SMO framework 105 can be configured to support the deployment and orchestration of RANs for both non-virtualized network elements and virtualized network elements. For non-virtualized network elements, the SMO framework 105 can be configured to support the deployment of dedicated physical resources for RAN coverage requirements, and these dedicated physical resources can be managed via an operation and maintenance interface (such as the O1 interface). For virtualized network elements, the SMO framework 105 can be configured to interact with a cloud computing platform (such as the Open Cloud (O-Cloud) 190) to perform network element lifecycle management (such as instantiating virtualized network elements) via a cloud computing platform interface (such as the O2 interface). Such virtualized network elements can include, but are not limited to, the CU 110, DU 130, RU 140, and the near RT RIC 125. In some embodiments, the SMO framework 105 can communicate with the hardware aspects of the 4G RAN (such as the Open eNB (O-eNB) 111) via the O1 interface. Additionally, in some embodiments, the SMO framework 105 can communicate directly with one or more RUs 140 via the O1 interface. The SMO framework 105 can also include a non-RT RIC 115 configured to support the functionality of the SMO framework 105.

[0046] The non-RT RIC 115 can be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence (AI) / machine learning (ML) (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 125. The non-RT RIC 115 can be coupled to or communicate with the near-RT RIC 125 (such as via the A1 interface). The near-RT RIC 125 can 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 the E2 interface) that connects one or more CUs 110, one or more DUs 130, or both, and the O-eNB to the near-RT RIC 125.

[0047] In some embodiments, to generate an AI / ML model to be deployed in the near-RT RIC 125, the non-RT RIC 115 can receive parameters or external enrichment information from an external server. Such information can be utilized by the near-RT RIC 125 and can be received from non-network data sources or from network functions at the SMO framework 105 or the non-RT RIC 115. In some examples, the non-RT RIC 115 or the near-RT RIC 125 can be configured to tune RAN behavior or performance. For example, the non-RT RIC 115 can monitor long-term trends and patterns of performance and employ an AI / ML model to perform corrective actions through the SMO framework 105 (such as via reconfiguration of O1) or via creation of RAN management policies (such as A1 policies).

[0048] At least one of CU 110, DU 130, and RU 140 may be referred to as base station 102. Thus, base station 102 may include one or more of CU 110, DU 130, and RU 140 (each component is indicated by a dashed line to indicate that each component may or may not be included in base station 102). Base station 102 provides an access point to core network 120 for UE 104. Base station 102 may include macro cells (high-power cellular base stations) and / or small cells (low-power cellular base stations). Small cells include femto cells, pico cells, and micro cells. A network including both small cells and macro cells may be referred to as a heterogeneous network. The heterogeneous network may also include a home evolved Node B (eNB) (HeNB), which may provide services to a restricted group referred to as a closed subscriber group (CSG). The communication link between RU 140 and UE 104 may include an uplink (UL) (also referred to as a reverse link) transmission from UE 104 to RU 140 and / or a downlink (DL) (also referred to as a forward link) transmission from RU 140 to UE 104. The communication link may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link may pass through one or more carriers. For each carrier allocated in carrier aggregation with a total of up to Yx MHz (x component carriers) for transmission in each direction, base station 102 / UE 104 may use a spectrum with a bandwidth of up to Y MHz (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, etc.). These 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 than for UL). Component carriers may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as the primary cell (PCell) and the secondary component carriers may be referred to as secondary cells (SCells).

[0049] Certain UEs 104 may use device-to-device (D2D) communication links 158 to communicate with each other. D2D communication links 158 may use DL / UL wireless wide area network (WWAN) spectrum. D2D communication links 158 may use one or more sidelink channels, such as the physical sidelink broadcast channel (PSBCH), the physical sidelink discovery channel (PSDCH), the physical sidelink shared channel (PSSCH), and the physical sidelink control channel (PSCCH). D2D communication may be through various wireless D2D communication systems, such as, for example, Bluetooth, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, LTE, or NR.

[0050] The wireless communication system may also include a Wi-Fi AP 150 that communicates with the UE 104 (also referred to as a Wi-Fi station (STA)) via a communication link 154, e.g., in a 5 GHz unlicensed spectrum, etc. When communicating in an unlicensed spectrum, the UE 104 / AP 150 may perform a Clear Channel Assessment (CCA) before communication to determine whether the channel is available.

[0051] The electromagnetic spectrum is generally subdivided into various categories, frequency bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating frequency bands have been identified as Frequency Range Designation FR1 (410 MHz - 7.125 GHz) and FR2 (24.25 GHz - 52.6 GHz). Although a part of FR1 is greater than 6 GHz, in various documents and articles, FR1 is generally (interchangeably) referred to as the "sub-6 GHz" band. Regarding FR2, a similar naming issue sometimes occurs, which is generally (interchangeably) referred to as the "millimeter wave" band in documents and articles, although it is different from the Extremely High Frequency (EHF) band (30 GHz - 300 GHz) identified by the International Telecommunication Union (ITU) as the "millimeter wave" band.

[0052] The frequencies between FR1 and FR2 are generally referred to as mid-band frequencies. Recent 5G NR research has identified the operating frequency bands for these mid-band frequencies as Frequency Range Designation FR3 (7.125 GHz - 24.25 GHz). The bands falling within FR3 may inherit FR1 characteristics and / or FR2 characteristics, and thus can effectively extend the features of FR1 and / or FR2 to the mid-band frequencies. In addition, higher frequency bands are currently being explored to extend 5G NR operation beyond 52.6 GHz. For example, three higher operating frequency bands have been identified as Frequency Range Designation FR2-2 (52.6 GHz - 71 GHz), FR4 (71 GHz - 114.25 GHz), and FR5 (114.25 GHz - 300 GHz). Each of these higher frequency bands falls within the EHF band.

[0053] Considering the above aspects, unless otherwise specifically stated, if the term "sub-6 GHz" etc. is used in this document, it may broadly represent frequencies that can be less than 6 GHz, can be within FR1, or can include mid-band frequencies. In addition, unless otherwise specifically stated, if the term "millimeter wave" etc. is used in this document, it may broadly represent frequencies that can include mid-band frequencies, can be within FR2, FR4, FR2-2, and / or FR5, or can be within the EHF band.

[0054] Base station 102 and UE 104 may each include multiple antennas (such as antenna elements, antenna panels, and / or antenna arrays) to facilitate beamforming. Base station 102 may transmit beamformed signal 182 to UE 104 in one or more transmission directions. UE 104 may receive the beamformed signal from base station 102 in one or more reception directions. UE 104 may also transmit beamformed signal 184 to base station 102 in one or more transmission directions. Base station 102 may receive the beamformed signal from UE 104 in one or more reception directions. Base station 102 / UE 104 may perform beam training to determine the optimal reception direction and the optimal transmission direction for each of base station 102 / UE 104. The transmission direction and the reception direction of base station 102 may be the same or may not be the same. The transmission direction and the reception direction of UE 104 may be the same or may not be the same.

[0055] Base station 102 may include and / or be referred to as a gNB, Node B, eNB, access point, base station transceiver, radio base station, radio transceiver, transceiver function, basic service set (BSS), extended service set (ESS), transmission reception point (TRP), network node, network entity, network equipment, or some other suitable term. Base station 102 may be implemented as an integrated access and backhaul (IAB) node, a relay node, a sidelink node, an aggregated (monolithic) base station with a baseband unit (BBU) (including a CU and a DU) and an RU, or may be implemented as a disaggregated base station including one or more of a CU, a DU, and / or an RU. A set of base stations including disaggregated base stations and / or aggregated base stations may be referred to as a next generation (NG) RAN (NG-RAN).

[0056] The core network 120 may include an Access and Mobility Management Function (AMF) 161, a Session Management Function (SMF) 162, a User Plane Function (UPF) 163, a Unified Data Management (UDM) 164, one or more Location Servers 168, and other functional entities. The AMF 161 is a control node that processes signaling between the UE 104 and the core network 120. The AMF 161 supports registration management, connection management, mobility management, and other functions. The SMF 162 supports session management and other functions. The UPF 163 supports packet routing, packet forwarding, and other functions. The UDM 164 supports the generation of Authentication and Key Agreement (AKA) credentials, user identity handling, access authorization, and subscription management. One or more Location Servers 168 are illustrated as including a Gateway Mobile Location Center (GMLC) 165 and a Location Management Function (LMF) 166. However, in general, one or more Location Servers 168 may include one or more location / locationing servers, which may include one or more of the GMLC 165, LMF 166, a Position Determination Entity (PDE), a Serving Mobile Location Center (SMLC), and a Mobile Positioning Center (MPC), etc. The GMLC 165 and LMF 166 support UE location services. The GMLC 165 provides an interface for clients / applications (e.g., emergency services) to access UE location information. The LMF 166 receives measurements and assistance information from the NG-RAN and the UE 104 via the AMF 161 to calculate the location of the UE 104. The NG-RAN may utilize one or more location methods to determine the location of the UE 104. Locating the UE 104 may involve signal measurements, location estimation, and optional speed calculation based on these measurements. The signal measurements may be performed by the UE 104 and / or the serving base station 102. The measured signals may be based on a Satellite Positioning System (SPS) 170 (e.g., a Global Navigation Satellite System (GNSS), Global Positioning System (GPS), Non-Terrestrial Network (NTN), or one or more of other satellite positioning / location systems), LTE signals, Wireless Local Area Network (WLAN) signals, Bluetooth signals, a Terrestrial Beacon System (TBS), sensor-based information (e.g., an atmospheric pressure sensor, a motion sensor), an NR Enhanced Cell ID (NR E-CID) method, NR signals (e.g., multi-round-trip time (multi-RTT), DL departure angle (DL-AoD), DL time difference of arrival (DL-TDOA), UL time difference of arrival (UL-TDOA), and UL arrival angle (UL-AoA) positioning), and / or one or more of other systems / signals / sensors.

[0057] Examples of the UE 104 include cellular phones, smart phones, Session Initiation Protocol (SIP) phones, laptop computers, personal digital assistants (PDAs), satellite radios, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablet computers, smart devices, wearable devices, vehicles, electricity meters, gas pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, or any other device with similar functionality. Some of the UEs in the UE 104 may be referred to as IoT devices (e.g., parking meters, gas pumps, toasters, vehicles, heart monitors, etc.). The UE 104 may also be referred to as a station, mobile station, subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, cell phone, user agent, mobile client, client, or some other suitable term. In some scenarios, the term "UE" may also apply to one or more companion devices, such as in a device constellation. One or more of these devices may access the network jointly and / or separately.

[0058] Referring again to Figure 1 , in some aspects, the UE 104 may include a PDU component 198 configured to: initiate a connection establishment with a second network to initiate a network change from a first network to the second network; send a registration request including a mobility registration indication to the second network in response to the initiation of the network change; send an identity indication to the second network in response to an identity request from the second network in response to the registration request; receive a registration acceptance indication from the second network in response to the sending of the identity indication; and send a PDU session establishment request to the second network indicating an existing PDU session from the first network for use on the second network.

[0059] Referring again to Figure 1 , in some aspects, the base station 102 may include a connection component 199 configured to: obtain a request to initiate a connection establishment with a UE to initiate a network change from a first network to a second network, where the network entity is associated with the second network; obtain a registration request including a mobility registration indication from the UE in response to the initiation of the network change; obtain an identity indication from the UE in response to an identity request provided to the UE in response to the registration request; provide a registration acceptance indication to the UE in response to the sending of the identity indication; and obtain a PDU session establishment request from the UE indicating an existing PDU session from the first network for use on the second network.

[0060] Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0061] Figure 2A FIG. 200 is an illustration that exemplifies a first subframe within a 5G NR frame structure. Figure 2B FIG. 230 is an illustration that exemplifies DL channels within a 5G NR subframe. Figure 2C FIG. 250 is an illustration that exemplifies a second subframe within a 5G NR frame structure. Figure 2D FIG. 280 is an illustration that exemplifies UL channels within a 5G NR subframe. The 5G NR frame structure may be frequency division duplexing (FDD) (wherein for a specific set of subcarriers (carrier system bandwidth), the subframes within that set of subcarriers are dedicated to DL or UL), or may be time division duplexing (TDD) (wherein for a specific set of subcarriers (carrier system bandwidth), the subframes within that set of subcarriers are dedicated to both DL and UL). In Figure 2A 、 Figure 2C the examples provided, the 5G NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (where most are DL), where D is DL, U is UL, and F is flexibly usable between DL / UL, and subframe 3 is configured with slot format 1 (where all are UL). Although subframes 3 and 4 are shown as having slot formats 1 and 28 respectively, any particular subframe may be configured with any of the various available slot formats 0 to 61. Slot formats 0 and 1 are all-DL and all-UL respectively. The other slot formats 2 - 61 include a mixture of DL, UL, and flexible symbols. The UE is configured with the slot format by receiving a slot format indicator (SFI) (configured dynamically by DL control information (DCI) or semi-statically / statically by radio resource control (RRC) signaling). Note that the following description also applies to the 5G NR frame structure as TDD.

[0062] Figures 2A to 2DThe frame structure is illustrated, and aspects of the present disclosure may be applicable to other wireless communication technologies that may have different frame structures and / or different channels. One frame (10 ms) may be divided into 10 equal-sized subframes (1 ms). Each subframe may include one or more time slots. The subframe may also include mini-slots, which may include 7, 4, or 2 symbols. Each time slot may include 14 or 12 symbols, depending on whether the cyclic prefix (CP) is normal or extended. For normal CP, each time slot may include 14 symbols, and for extended CP, each time slot may include 12 symbols. The symbols on the DL may be CP orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbols. The symbols on the UL may be CP-OFDM symbols (for high-throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (for power-constrained scenarios; limited to single-stream transmission). The number of time slots within a subframe is based on the CP and the parameter set. The parameter set defines the subcarrier spacing (SCS) (see Table 1). The symbol length / duration may be scaled using 1 / SCS.

[0063]

[0064] Table 1: Parameter Sets, SCS, and CP

[0065] For normal CP (14 symbols / slot), different parameter sets μ0 to 4 allow 1, 2, 4, 8, and 16 time slots per subframe, respectively. For extended CP, parameter set 2 allows 4 time slots per subframe. Thus, for normal CP and parameter set μ, there are 14 symbols / slot and 2 μ time slots / subframe. The subcarrier spacing may be equal to 2 μ * 15 kHz, where μ is parameter set 0 to 4. Thus, the subcarrier spacing for parameter set μ = 0 is 15 kHz, and the subcarrier spacing for parameter set μ = 4 is 240 kHz. The symbol length / duration is negatively correlated with the subcarrier spacing. Figures 2A to 2D An example is provided with normal CP having 14 symbols per time slot and parameter set μ = 2 having 4 time slots per subframe. The time slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs. Within a frame set, there may be one or more different bandwidth parts (BWPs) that are frequency division multiplexed (see Figure 2B ). Each BWP may have a specific parameter set and CP (normal or extended).

[0066] The resource grid can be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as a physical RB (PRB)) that extends over 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0067] As Figure 2A illustrated, some of the REs in the RE carry reference (pilot) signals (RSs) for the UE. The RS can include a demodulation RS (DM-RS) (designated as R for a specific configuration, but other DM-RS configurations are possible) and a channel state information reference signal (CSI-RS) for channel estimation at the UE. The RS can also include a beam measurement RS (BRS), a beam refinement RS (BRRS), and a phase tracking RS (PT-RS).

[0068] Figure 2B 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) (e.g., 1, 2, 4, 8, or 16 CCEs), each CCE including six resource element groups (REGs), each REG including 12 consecutive REs in the OFDM symbols of an RB. The PDCCH within a BWP can be referred to as a control resource set (CORESET). The UE is configured to monitor PDCCH candidates in the PDCCH search space (e.g., common search space, UE-specific search space) during a PDCCH monitoring occasion on the CORESET, where the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs can be located at higher and / or lower frequencies on the channel bandwidth. The primary synchronization signal (PSS) can be in symbol 2 of a specific subframe of the frame. The PSS is used by the UE 104 to determine subframe / symbol timing and the physical layer identity. The secondary synchronization signal (SSS) can be in symbol 4 of a specific subframe of the frame. The SSS is used by the UE to determine the physical layer cell identity group number and the radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the location of the DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and the SSS to form a synchronization signal (SS) / PBCH block (also referred to as an SS block (SSB)). The MIB provides the number of RBs in the system bandwidth and the system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not sent via the PBCH (such as system information blocks (SIBs)), and paging messages.

[0069] As Figure 2CAs illustrated, some of the REs in the RE carry DM-RS (indicated as R for a specific configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE can transmit the DM-RS of the physical uplink control channel (PUCCH) and the DM-RS of the physical uplink shared channel (PUSCH). The PUSCH DM-RS can be transmitted in the previous one or two symbols of the PUSCH. Depending on whether a short PUCCH or a long PUCCH is transmitted and depending on the specific PUCCH format used, the PUCCH DM-RS can be transmitted in different configurations. The UE can transmit the sounding reference signal (SRS). The SRS can be transmitted in the last symbol of the subframe. The SRS can have a comb structure, and the UE can transmit the SRS on one of the combs. The SRS can be used by the base station for channel quality estimation to enable frequency-dependent scheduling of the UL.

[0070] Figure 2D Examples of various UL channels within a subframe of a frame are illustrated. The PUCCH can be located at the position indicated in one configuration. The PUCCH carries uplink control information (UCI), such as a scheduling request, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and a hybrid automatic repeat request (HARQ) acknowledgment (ACK) (HARQ-ACK) feedback (i.e., one or more HARQ ACK bits indicating one or more ACKs and / or negative ACKs (NACKs)). The PUSCH carries data and can be used in addition to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0071] Figure 3It is a block diagram of the communication between the base station 310 and the UE 350 in the access network. In the DL, Internet Protocol (IP) packets can be provided to the controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes the Radio Resource Control (RRC) layer, and layer 2 includes the Service Data Adaptation Protocol (SDAP) layer, the Packet Data Convergence Protocol (PDCP) layer, the Radio Link Control (RLC) layer, and the Medium Access Control (MAC) layer. The controller / processor 375 provides RRC layer functionality associated with the broadcast of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs), error correction via ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functionality associated with the mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0072] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes the physical (PHY) layer, may include error detection on the transport channel, forward error correction (FEC) encoding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 handles the mapping to the signal constellation based on various modulation schemes such as binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase phase shift keying (M-PSK), and M-order quadrature amplitude modulation (M-QAM). The encoded and modulated symbols may then be split into parallel streams. Subsequently, each stream may be mapped to OFDM subcarriers, multiplexed with reference signals (e.g., pilots) in the time and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain OFDM symbol stream. The OFDM stream is space precoded to generate multiple spatial streams. Channel estimates from the channel estimator 374 may be used to determine the encoding and modulation schemes, as well as for spatial processing. The channel estimates may be derived from reference signals transmitted by the UE 350 and / or channel status feedback. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318Tx. Each transmitter 318Tx may modulate a radio frequency (RF) carrier using the corresponding spatial stream for transmission.

[0073] At the UE 350, each receiver 354Rx receives signals via its corresponding antenna 352. Each receiver 354Rx recovers the information modulated onto the RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then uses a fast Fourier transform (FFT) to convert the OFDM symbol stream from the time domain to the frequency domain. The frequency-domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier and the reference signals are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on the channel estimates computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the controller / processor 359, which implements layer 3 and layer 2 functionality.

[0074] The controller / processor 359 may be associated with a memory 360 that stores program code and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets. The controller / processor 359 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0075] Similar to the functionality described in connection with DL transmission by the base station 310, the controller / processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functionality associated with the mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0076] The TX processor 368 may use channel estimates derived by the channel estimator 358 from reference signals or feedback transmitted by the base station 310 to select appropriate decoding and modulation schemes and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via the respective transmitters 354Tx. Each transmitter 354Tx may modulate an RF carrier with a respective spatial stream for transmission.

[0077] UL transmission is processed at the base station 310 in a manner similar to that described in connection with the receiver functionality at the UE 350. Each receiver 318Rx receives signals via its respective antenna 320. Each receiver 318Rx recovers the information modulated onto the RF carrier and provides the information to the RX processor 370.

[0078] The controller / processor 375 may be associated with a memory 376 that stores program code and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover IP packets. The controller / processor 375 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0079] At least one of TX processor 368, RX processor 356, and controller / processor 359 may be configured to perform aspects associated with Figure 1 PDU component 198.

[0080] At least one of TX processor 316, RX processor 370, and controller / processor 375 may be configured to perform aspects associated with Figure 1 connection component 199.

[0081] In a wireless communication system (such as in a mmW stand-alone system), different networks operating in different frequency ranges (e.g., FR1, FR2) may utilize hardware from different vendors. In the case where different networks operating in different frequency ranges are using hardware from different vendors, the inter-AMF interface (e.g., N14) may not be deployed. However, in the case where different networks operating in different frequency ranges are using hardware from the same vendor, the inter-AMF interface (e.g., N14) may be deployed. Referring to Figure 4A illustration 400, illustration 400 includes a user plane function (UPF) and a session management function (SMF), where UPF+SMF 402 may be configured to provide data processing for AMF1 404 or AMF2 406. Each of AMF1 and AMF2 has an interface N2 412, 414 to a respective base station (BS) 408, 410. BS 408 may operate on FR1, while BS 410 may operate on FR2. The hardware components in illustration 400 may use the same vendor, such that the inter-AMF interface (e.g., N14 416) is supported between AMF1 404 and AMF2 406. In some cases, UPF+SMF 402 may be shared by both BS 408 and BS 410, since UPF+SMF 402 may be from another vendor. However, referring to Figure 4B illustration 420, in the case where the hardware for at least the AMF (e.g., 404, 406) is from different vendors, the inter-AMF interface may not be deployed. In the case where the inter-AMF interface is not deployed, seamless mobility may not be possible. For example, the UE may not be able to use handover and may only use redirection.

[0082] Figure 5 is an illustration that exemplifies a call flow where the inter-AMF interface is not deployed. Illustration 500 includes UE 502, a first network 504, and a second network 506.

[0083] As indicated at 508, the UE 502 may be in a connected mode with the first network 504. The UE 502 may determine that it wants to switch from the first network 504 to the second network 506. The UE 502 may determine to switch to the second network for various reasons such as, but not limited to, coverage degradation from the first network or the second network providing better coverage than the first network. In such cases, the UE 502 may receive an RRC release 510 from the first network 504. Then, the UE may initiate a connection request with the second network by sending an RRC connection establishment 512 to the second network 506. The UE may send a registration request 514 to the second network. However, the second network may respond by sending a registration rejection 516 to the UE. The second network may reject the registration because the UE identity may not be derived by the second network. Then, in response to the registration rejection 516, the second network may send an RRC release 518 to the UE.

[0084] Then, at 520, the UE 502 may re-initiate an RRC connection establishment with the second network. The UE may send a registration request 522 to the second network. However, the registration request 522 is an initial registration request. At 524, an authentication and security procedure may be performed in response to the initial registration request. After the authentication and security procedure is completed, the UE may provide UE capabilities 526 to the second network. The UE may provide UE capabilities 526 to the second network in response to a request for UE capabilities from the second network.

[0085] At 528, a registration procedure may be performed between the UE and the second network. For example, the second network may provide a registration acceptance indication, and the UE may respond with a registration completion indication. After the registration procedure is completed, the UE may send a PDU session establishment request 530. The PDU session establishment request 530 is an initial request for a PDU session because the UE connection request is being rejected (e.g., registration rejection 516). In response to the PDU session establishment request 530, the UE may receive an indication to accept the initiation of a PDU session with the second network. Once the RRC connection completion 532 is received, the connection with the second network may be completed. The UE 502 may be connected to the second network and may be in a connected mode with the second network, as shown at 534.

[0086] Although the UE 502 is in a connected mode with a second network, the AMF inter - interface (e.g., N14) may not be deployed and the UE must perform an initial registration and an initial request for PDU session establishment, which may delay the mobility process. Additionally, when the UE is in a connected mode with the second network, the IP address that the UE had when connected to the first network may not be utilized. Partly because the PDU session establishment request is an initial request, the UE receives a new IP address when connecting to the second network. Due to the lack of deployment of the AMF inter - interface (e.g., N14), when switching to the second network, the PDU session that the UE had on the first network may not be available to the UE. Thus, the UE is assigned a new IP address, and the change of this IP address may significantly affect a voice call (e.g., voice over NR) and cause the voice call to drop.

[0087] Aspects presented herein provide a configuration that allows for supporting an AMF inter - interface in cases where hardware from different vendors is used at least for the AMFs between different networks. At least one advantage of the present disclosure is that a UE switching from a first network to a second network can utilize an existing PDU session utilized on the first network when switching to the second network. Using the existing PDU session on the second network or the newly connected network can allow the UE to maintain services that utilize the existing PDU session and not experience any service interruption.

[0088] Figure 6 is a diagram illustrating an example of a call flow where an AMF inter - interface is deployed. Diagram 600 includes a UE 602, a first network 604, and a second network 606.

[0089] As indicated at 608, the UE 602 may be in a connected mode with the first network 604. The UE 602 may determine that it wants to switch from the first network 604 to the second network 606. For example, as discussed above, the UE 602 may determine to switch to the second network for various reasons. In response to initiating a switch to the second network 606, the UE 602 may receive an RRC release 610 from the first network 604. Then, the UE may initiate a connection request to the second network by sending an RRC connection establishment 612 to the second network 606. The UE may also send a registration request 614 to the second network. The registration request 614 may include a globally unique temporary identifier (GUTI) and a mobility registration update. Refer to Figure 7In the illustration 700, the GUTI 716 may include a Mobile Country Code (MCC) and a Mobile Network Code (MNC) 702, an AMF Region Identifier (ID) 704, an AMF Set ID 706, an AMF Pointer 708, and / or a Temporary Mobile Subscriber Identity (TMSI) 710. The GUTI 716 may include an S-TMSI 712, where the S-TMSI may include an AMF Set ID 706, an AMF Pointer 708, and a TMSI 710. The GUTI 716 may include a Globally Unique AMF ID (GUAMI) 714. The GUAMI 714 may at least include an MCC and an MNC 702, an AMF Region ID 704, an AMF Set ID 706, and / or an AMF Pointer 708.

[0090] The AMF associated with the second network 606 may receive a registration request 614 that includes a GUTI, but the AMF associated with the second network 606 may not be able to locate the UE 602 based on the GUTI within the registration request 614. Instead of rejecting the registration request, at 616, the second network may provide an identification request to the UE, and the UE may respond with the UE's Subscription Permanent Identifier (SUPI). The second network may use the UE's SUPI to verify the UE's identity. For example, the second network may provide the UE's SUPI to a User Data Management (UDM) or a Home Subscriber Server (HSS) to verify the UE's SUPI. Additionally, the AMF associated with the second network 606 may use the GUAMI of the GUTI associated with the AMF associated with the first network to assist in the identification of the UE 602. For example, the second network may request the UE's International Mobile Subscriber Identity (IMSI) or Subscription Concealed Identifier (SUCI) to identify the UE. The AMF associated with the second network may use the UE's SUPI, SUCI, or IMSI to identify any existing PDU sessions with a UPF and / or an SMF.

[0091] At 618, the authentication and security process with the second network may be completed. For example, the AMF associated with the second network may authenticate the UE 602 on the second network. After completing the authentication and security process with the second network, the AMF associated with the second network may register the UE with a UPF, an SMF, and a UDM, such that the UE may deregister from the AMF associated with the first network. For example, the AMF associated with the second network may notify the UDM that the UE 602 has joined the AMF associated with the second network, such that the AMF associated with the first network is notified that the UE 602 has joined a new AMF and is released from the AMF associated with the first network.

[0092] At 620, the UE may provide an indication of the UE capabilities 620 to the second network. The UE capabilities 620 may indicate to the second network that the UE supports the existing PDU session establishment process.

[0093] At 622, a registration process to the second network may occur. For example, the second network may provide a registration acceptance indication to the UE, and the UE may respond with a registration completion indication.

[0094] At 624, the UE may send a PDU session establishment request 624. The PDU session establishment request 624 may include a request for an existing PDU session. For example, the UE may request the second network to utilize the existing PDU session that the UE used when on the first network. The AMF associated with the second network may forward the PDU session establishment request to the UPF and the SMF to utilize the existing PDU session on the second network. Since the identity of the UE 602 has been determined previously, the existing PDU session request may be granted at least during the authentication and security process 618, such that the UE 602 may utilize on the second network the existing PDU session that the UE utilized on the first network. Thus, the UE 602 may continue to use on the second network the IP address that it used on the first network without service interruption due to the handover from the first network to the second network.

[0095] At 626, the RRC connection process may be completed. For example, the second network may provide an RRC reconfiguration to the UE, and the UE may respond by sending an RRC reconfiguration complete indication.

[0096] At 628, the UE 602 is in a connected mode with the second network 606. The UE 802 may communicate with the second network using the existing PDU session.

[0097] In Figure 6 certain aspects, the UE and the second network may need to know each other so that the PDU session establishment request can use the existing PDU session on the second network. The UE may know that switching to a different network using a different frequency range may trigger the use of an existing PDU session establishment instead of requesting an initial PDU session establishment. The UE may know that the network may be able to perform an existing PDU session establishment process based on the authentication and security process in the mobility registration, followed by a registration acceptance indication that includes a PDU session status information element in which all PDU sessions are set to inactive. The network may assume that the UE is capable of performing an existing PDU session establishment process based on the last registered tracking area identity (TAI) transmitted in the registration request. The network may know that the UE supports the existing PDU session establishment process based on the UE's indication in the registration request of the ability to support interworking without N26. Supporting interworking without N26 may be an implicit indication that the UE supports the existing PDU session establishment process. By the network indicating support for interworking without N26, the UE may know that the network supports the existing PDU session establishment process.

[0098] Figure 8It is a diagram illustrating an example of a call flow in which an interface between AMFs is deployed. Diagram 800 includes a UE 802, a first network 804, and a second network 806. Figure 8 Many steps / processes of diagram 800 can be the same as or similar to those of Figure 6 diagram 600, such that duplicate descriptions may not be included.

[0099] As indicated at 808, UE 802 may be in a connected mode with the first network 804. UE 802 may determine that it wants to switch from the first network 804 to the second network 806. For example, as discussed above, UE 802 may determine to switch to the second network for various reasons. In response to initiating a handover to the second network 806, UE 802 may receive an RRC release 810 from the first network 804. Then, the UE may initiate a connection request to the second network by sending an RRC connection establishment 812 to the second network 806. The UE may also send a registration request 814 to the second network. The registration request 814 may include a GUTI and a mobility registration update. The registration request 814 may also include an indication of support for interworking without N14. The indication of support for interworking without N14 may notify the AMF associated with the second network that, instead of rejecting the registration request, the GUAMI of the GUTI is related to another AMF (e.g., the AMF associated with the first network) and includes the same MCC+MNC and AMF area ID as the AMF associated with the second network. The MCC+MNC and AMF area ID may be included in a pre-configured list for performing an existing PDU session establishment request procedure. Instead of rejecting the registration request, at 816, the second network may provide an identity request to the UE, and the UE may respond with the UE's SUPI.

[0100] At 818, the authentication and security process with the second network may be completed. For example, the AMF associated with the second network may authenticate UE 802 on the second network. After completing the authentication and security process with the second network, the AMF associated with the second network may register the UE with the UPF, SMF, and UDM, such that the UE may deregister from the AMF associated with the first network. For example, the AMF associated with the second network may notify the UDM that UE 802 has joined the AMF associated with the second network, such that the AMF associated with the first network is notified that UE 802 has joined the new AMF and is released from the AMF associated with the first network.

[0101] At 820, the UE may provide an indication of UE capabilities 820 to the second network. The UE capabilities 820 may indicate to the second network that the UE supports the existing PDU session establishment process.

[0102] At 822, a registration process to the second network may occur. For example, the second network may provide a registration acceptance indication to the UE, and the UE may respond with a registration completion indication. The registration acceptance indication may include an information element indicating interworking without N14 for the UE, and this information element may trigger the UE to use handover for the PDU session.

[0103] At 824, the UE may send a PDU session establishment request 824. The PDU session establishment request 824 may include a request for an existing PDU session. For example, the UE may request the second network to use the existing PDU session that the UE used when on the first network. The AMF associated with the second network may forward the PDU session establishment request to the UPF and the SMF to utilize the existing PDU session on the second network. Since the identity of the UE 802 has been previously determined, the existing PDU session request may be granted at least during the authentication and security process 818, such that the UE 802 may utilize the existing PDU session on the second network that the UE used on the first network. Thus, the UE 802 may continue to use the IP address on the second network without service interruption due to the handover from the first network to the second network.

[0104] At 826, the RRC connection process may be completed. For example, the second network may provide RRC reconfiguration to the UE, and the UE may respond by sending an RRC reconfiguration complete indication.

[0105] At 828, the UE 802 is in a connected mode with the second network 806. The UE 802 may communicate with the second network using the existing PDU session.

[0106] Figure 9 is a call flow diagram 900 of the signaling between the UE 902 and the network entity 904. The network entity 904 may include a base station configured to provide at least one cell. The UE 902 may be configured to communicate with the network entity 904. For example, in Figure 1 context, the network entity 904 may correspond to the base station 102 and the UE 902 may at least correspond to the UE 104. In another example, in Figure 3 context, the network entity 904 may correspond to the base station 310 and the UE 902 may correspond to the UE 350.

[0107] At 906, the UE 902 may initiate the establishment of a connection with a second network. The UE may initiate the establishment of a connection with the second network to initiate a network change from the first network to the second network. The UE may be connected to or communicating with the first network and may initiate a network change to the second network. The network entity 904 may be associated with the second network, where the UE initiates the establishment of a connection with the second network via the network entity 904. The network entity 904 may receive a request from the UE 902 to initiate the establishment of a connection with the UE 902 to initiate a network change. The connection establishment may include the establishment of a Radio Resource Control (RRC) connection with the second network. The UE may initiate the establishment of a connection with the second network based on any one of the aspects combined Figures 6 to 8 with any one of the aspects described above.

[0108] At 908, the UE 902 may send a registration request including a mobility registration indication in response to initiating a network change. The UE may send the registration request to the second network via the network entity 904. For example, the UE may send a registration request to the network entity 904 associated with the second network. The network entity 904 may receive the registration request from the UE 902. In some aspects, the mobility registration indication may include a GUTI. The GUTI may include a Mobile Country Code (MCC), a Mobile Network Code (MNC), an Access and Mobility Management Function (AMF) area identifier (ID), an AMF set ID, an AMF pointer, and / or a Temporary Mobile Subscriber Identity (TMSI). In some aspects, the GUTI may include a Globally Unique AMF ID (GUAMI). Where the GUAMI may be composed of at least the MCC, MNC, AMF area ID, AMF set ID, and / or AMF pointer. In some aspects, the registration request may include a PDU session establishment indication indicating that the UE supports the existing PDU session establishment procedure. The PDU session establishment indication may include at least one of a TAI or an interworking indication. In some aspects, the registration request may include an interworking indication indicating support for an interworking feature. The UE may support the existing PDU session establishment procedure based on the interworking indication indicating support for an interworking feature. The UE may send the registration request to the second network based on any one of the aspects combined Figures 6 to 8 with any one of the aspects described above.

[0109] At 910, the UE 902 may send an identity indication in response to an identity request from a second network. The UE 902 may send the identity indication to the second network via the network entity 904. The network entity 904 may receive the identity indication from the UE 902. The UE may send an identity indication in response to an identity request in response to a registration request from the second network. The network entity 904 may send an identity request to the UE 902 in response to the UE 902 sending a registration request. The UE may receive an identity request from the second network in response to sending a registration request. In some aspects, the identity indication may include at least one of a Subscription Permanent Identifier (SUPI), a Subscription Concealed Identifier (SUCI), or an International Mobile Subscriber Identity (IMSI). The UE may be authenticated by the second network based on the identity indication. The UE may send the identity indication to the second network based on any one of the aspects combined Figures 6 to 8 with any one of the aspects described above.

[0110] At 912, the network entity 904 may send a registration acceptance indication. The network entity 904 may send the registration acceptance indication to the UE 902. The UE 902 may receive the registration acceptance indication from the network entity 904. The network entity may provide a registration acceptance indication in response to the sending of an identity indication from the UE. The network entity may obtain the identity indication from the UE and provide a registration acceptance indication in response to the identity indication from the UE. In some aspects, the registration acceptance indication may include an interworking indication indicating that the second network supports the existing PDU session establishment procedure. The network entity may send the registration acceptance indication to the UE based on any one of the aspects combined Figures 6 to 8 with any one of the aspects described above.

[0111] At 914, the UE 902 may send a PDU session establishment request. The UE may send a PDU session establishment request to the second network. The UE may send a PDU session establishment request indicating an existing PDU session from the first network for use on the second network. The PDU session establishment request may include a request for an existing PDU session from the first network for use on the second network. In some aspects, the PDU session establishment request may be sent based on the initiation of a network change. For example, the second network may use a different frequency range from the first network. In this case, when making a network change from the first network to the second network, since the UE uses different frequency ranges, the sending of the PDU session establishment request by the UE may be triggered. In some aspects, the UE may determine that the second network supports the establishment of an existing PDU session at the second network based on an indication received during the authentication of the UE by the second network. The UE may send the PDU session establishment request to the second network based on any one of the aspects combined Figures 6 to 8 with any one of the aspects described above.

[0112] At 916, the UE 902 may communicate with a second network via the network entity 904. The UE may communicate with the second network using an existing PDU session. The UE may communicate with the second network using the existing PDU session that the UE used when communicating with the first network. When transitioning to the second network, the UE using the existing PDU session on the second network allows the UE to maintain settings or parameters without having to update or request a new PDU session. For example, the UE using the existing PDU session on the second network allows the UE to maintain the same IP address so that existing communications are not lost or dropped due to the handover to the second network. The UE may use the existing PDU session to communicate with the second network based on any of the aspects described in conjunction with Figures 6 to 8 any of the aspects described above.

[0113] Figure 10 is a flowchart 1000 of a method of wireless communication. The method may be performed by a UE (e.g., UE 104; device 1204). One or more of the illustrated operations may be omitted, reordered, or performed simultaneously. The method may allow the UE to utilize an existing PDU session when changing to a different network.

[0114] At 1002, the UE may initiate the establishment of a connection with the second network. For example, 1002 may be performed by the PDU component 198 of the device 1204. The UE may initiate the establishment of a connection with the second network to initiate a network change from the first network to the second network, as shown in conjunction with Figures 6 to 8 any of those shown in. The UE may be connected to or communicating with the first network and may initiate a network change to the second network. The connection establishment may include the establishment of an RRC connection with the second network.

[0115] At 1004, in response to initiating the network change, the UE may send a registration request including a mobility registration indication, as shown in conjunction with Figures 6 to 8as shown in any of them. For example, 1004 may be performed by the PDU component 198 of the device 1204. The UE may send a registration request to the second network. For example, the UE may send a registration request to a network entity associated with the second network. In some aspects, the mobility registration indication may include a GUTI. The GUTI may include MCC, MNC, AMF area ID, AMF set ID, AMF pointer, and / or TMSI. In some aspects, the GUTI may include a GUAMI. Wherein the GUAMI may be composed of at least MCC, MNC, AMF area ID, AMF set ID, and / or AMF pointer. In some aspects, the registration request may include a PDU session establishment indication indicating that the UE supports the existing PDU session establishment process. The PDU session establishment indication may include at least one of TAI or an interworking indication. In some aspects, the registration request may include an interworking indication indicating support for interworking features. The UE may support the existing PDU session establishment process based on the interworking indication indicating support for interworking features.

[0116] At 1006, the UE may send an identity indication to the second network in response to an identity request from the second network. For example, 1006 may be performed by the PDU component 198 of the device 1204. The UE may send an identity indication in response to an identity request from the second network in response to a registration request, as shown in any of Figures 6 to 8 them. The UE may receive an identity request from the second network in response to sending a registration request. In some aspects, the identity indication may include at least one of SUPI, SUCI, or IMSI. The UE may be authenticated by the second network based on the identity indication.

[0117] At 1008, the UE may receive a registration acceptance indication. For example, 1008 may be performed by the PDU component 198 of the device 1204. The UE may receive a registration acceptance indication from the second network. The UE may receive a registration acceptance indication in response to sending an identity indication, as shown in any of Figures 6 to 8 them. In some aspects, the registration acceptance indication may include an interworking indication indicating that the second network supports the existing PDU session establishment process.

[0118] At 1010, the UE may send a PDU session establishment request. For example, 1010 may be performed by the PDU component 198 of the device 1204. The UE may send a PDU session establishment request to the second network. The UE may send a PDU session establishment request indicating an existing PDU session from the first network for use on the second network, as shown in any of Figures 6 to 8as shown in any of them. The PDU session establishment request may include a request for an existing PDU session from the first network for use on the second network. In some aspects, the PDU session establishment request may be sent based on the initiation of a network change. For example, the second network may use a different frequency range than the first network. In this case, when a network change from the first network to the second network is made, the PDU session establishment request may be triggered because the UE utilizes different frequency ranges. In some aspects, the UE may determine that the second network supports the establishment of an existing PDU session at the second network based on an indication received during the authentication of the UE by the second network.

[0119] Figure 11 is a flowchart 1100 of a method for wireless communication. The method may be performed by a UE (e.g., UE 104; device 1204). One or more of the illustrated operations may be omitted, reordered, or performed simultaneously. The method may allow the UE to utilize an existing PDU session when changing to a different network.

[0120] At 1102, the UE may initiate the establishment of a connection with the second network. For example, 1102 may be performed by the PDU component 198 of the device 1204. The UE may initiate the establishment of a connection with the second network to initiate a network change from the first network to the second network, as described in connection with Figures 6 to 8 any of them. The UE may be connected to or communicating with the first network and may initiate a network change to the second network. The connection establishment may include the establishment of a radio resource control (RRC) connection with the second network.

[0121] At 1104, in response to initiating the network change, the UE may send a registration request including a mobility registration indication, as described in connection with Figures 6 to 8as shown in any of them. For example, 1104 may be performed by the PDU component 198 of the device 1204. The UE may send a registration request to the second network. For example, the UE may send a registration request to a network entity associated with the second network. In some aspects, the mobility registration indication may include a globally unique temporary identifier (GUTI). The GUTI may include a mobile country code (MCC), a mobile network code (MNC), an access and mobility management function (AMF) area identifier (ID), an AMF set ID, an AMF pointer, and / or a temporary mobile subscriber identity (TMSI). In some aspects, the GUTI may include a globally unique AMF ID (GUAMI). Wherein the GUAMI may be composed of at least the MCC, MNC, AMF area ID, AMF set ID, and / or AMF pointer. In some aspects, the registration request may include a PDU session establishment indication indicating that the UE supports the existing PDU session establishment process. The PDU session establishment indication may include at least one of a tracking area identity (TAI) or an interworking indication. In some aspects, the registration request may include an interworking indication indicating support for interworking features. The UE may support the existing PDU session establishment process based on the interworking indication indicating support for interworking features.

[0122] At 1106, the UE may send an identity indication to the second network in response to an identity request from the second network. For example, 1106 may be performed by the PDU component 198 of the device 1204. The UE may send an identity indication in response to an identity request from the second network in response to a registration request, as combined Figures 6 to 8 as shown in any of them. The UE may receive an identity request from the second network in response to sending a registration request. In some aspects, the identity indication may include at least one of a subscription permanent identifier (SUPI), a subscription concealed identifier (SUCI), or an international mobile subscriber identity (IMSI). The UE may be authenticated by the second network based on the identity indication.

[0123] At 1108, the UE may receive a registration acceptance indication. For example, 1108 may be performed by the PDU component 198 of the device 1204. The UE may receive a registration acceptance indication from the second network. The UE may receive a registration acceptance indication in response to sending an identity indication, as combined Figures 6 to 8 as shown in any of them. In some aspects, the registration acceptance indication may include an interworking indication indicating that the second network supports the existing PDU session establishment process.

[0124] At 1110, the UE may send a PDU session establishment request. For example, 1110 may be performed by the PDU component 198 of the device 1204. The UE may send a PDU session establishment request to the second network. The UE may send a PDU session establishment request indicating an existing PDU session from the first network for use on the second network, as combined Figures 6 to 8as shown in any of them. The PDU session establishment request may include a request for an existing PDU session from the first network for use on the second network. In some aspects, the PDU session establishment request may be sent based on the initiation of a network change. For example, the second network may use a different frequency range than the first network. In such a case, when a network change from the first network to the second network is made, the PDU session establishment request may be triggered since the UE utilizes different frequency ranges. In some aspects, the UE may determine that the second network supports the establishment of an existing PDU session at the second network based on an indication received during authentication of the UE at the second network.

[0125] At 1112, the UE may communicate with the second network. For example, 1112 may be performed by the PDU component 198 of the device 1204. The UE may communicate with the second network using an existing PDU session, as shown in any of Figures 6 to 8 them. The UE may communicate with the second network using the existing PDU session that the UE used when communicating with the first network. When transitioning to the second network, the UE using the existing PDU session on the second network allows the UE to maintain settings or parameters without having to update or request a new PDU session. For example, the UE using the existing PDU session on the second network allows the UE to maintain the same IP address such that existing communications are not lost or dropped due to the handover to the second network.

[0126] Figure 12FIG. 1200 is a diagram illustrating an example of a hardware implementation for apparatus 1204. Apparatus 1204 may be a UE, a component of a UE, or may implement UE functionality. In some aspects, apparatus 1204 may include a cellular baseband processor 1224 (also referred to as a modem), which is coupled to one or more transceivers 1222 (e.g., cellular RF transceivers). The cellular baseband processor 1224 may include on-chip memory 1224'. In some aspects, apparatus 1204 may also include one or more subscriber identity module (SIM) cards 1220 and an application processor 1206 coupled to a secure digital (SD) card 1208 and a screen 1210. The application processor 1206 may include on-chip memory 1206'. In some aspects, apparatus 1204 may also include a Bluetooth module 1212, a WLAN module 1214, an SPS module 1216 (e.g., GNSS module), one or more sensor modules 1218 (e.g., barometric pressure sensor / altimeter; motion sensors such as an inertial measurement unit (IMU), gyroscope, and / or accelerometer; light detection and ranging (LIDAR), radio assisted detection and ranging (RADAR), sound navigation and ranging (SONAR), magnetometer, audio, and / or other technologies for positioning), an additional memory module 1226, a power supply 1230, and / or a camera 1232. The Bluetooth module 1212, the WLAN module 1214, and the SPS module 1216 may include on-chip transceivers (TRX) (or in some cases, only receivers (RX)). The Bluetooth module 1212, the WLAN module 1214, and the SPS module 1216 may include their own dedicated antennas and / or communicate using antenna 1280. The cellular baseband processor 1224 communicates with UE 104 and / or with the RU associated with network entity 1202 via transceiver 1222 through one or more antennas 1280. The cellular baseband processor 1224 and the application processor 1206 may each separately include computer-readable media / memory 1224', 1206'. The additional memory module 1226 may also be considered computer-readable media / memory. Each computer-readable media / memory 1224', 1206', 1226 may be non-transitory. The cellular baseband processor 1224 and the application processor 1206 are each responsible for general processing, including executing software stored on the computer-readable media / memory. The software, when executed by the cellular baseband processor 1224 / application processor 1206, causes the cellular baseband processor 1224 / application processor 1206 to perform the various functions described above. The computer-readable media / memory may also be used to store data manipulated by the cellular baseband processor 1224 / application processor 1206 when executing the software.The cellular baseband processor 1224 / application processor 1206 can be a component of the UE 350 and can include the memory 360 and / or at least one of the TX processor 368, the RX processor 356, and the controller / processor 359. In one configuration, the device 1204 can be a processor chip (modem and / or application) and include only the cellular baseband processor 1224 and / or the application processor 1206, while in another configuration, the device 1204 can be the entire UE (e.g., see. Figure 3 of 350) and include additional modules of the device 1204.

[0127] As discussed above, component 198 is configured to initiate connection establishment with a second network to initiate a network change from a first network to the second network; send a registration request including a mobility registration indication to the second network in response to the initiation of the network change; send an identity indication to the second network in response to an identity request from the second network in response to the registration request; receive a registration acceptance indication from the second network in response to the sending of the identity indication; and send a PDU session establishment request to the second network indicating an existing PDU session from the first network for use on the second network. Component 198 may be within cellular baseband processor 1224, application processor 1206, or both cellular baseband processor 1224 and application processor 1206. Component 198 may be one or more hardware components specifically configured to perform the stated processes / algorithms, implemented by one or more processors configured to perform the stated processes / algorithms, stored in a computer-readable medium for implementation by one or more processors, or some combination thereof. As shown, device 1204 may include various components configured for various functions. In one configuration, device 1204 (and particularly cellular baseband processor 1224 and / or application processor 1206) includes means for receiving an indication to initiate connection establishment with a second network to initiate a network change from a first network to the second network. The device includes means for sending a registration request including a mobility registration indication to the second network in response to the initiation of the network change. The device includes means for sending an identity indication to the second network in response to an identity request from the second network in response to the registration request. The device includes means for receiving a registration acceptance indication from the second network in response to the sending of the identity indication. The device includes means for sending a PDU session establishment request to the second network indicating an existing PDU session from the first network for use on the second network. The device further includes means for communicating with the second network using the existing PDU session. The means may be component 198 of device 1204 configured to perform the functions recited by the means. As described above, device 1204 may include TX processor 368, RX processor 356, and controller / processor 359. Thus, in one configuration, the means may be TX processor 368, RX processor 356, and / or controller / processor 359 configured to perform the functions recited by the means.

[0128] Figure 13 is a flowchart 1300 of a method of wireless communication. The method may be performed by a network entity (e.g., base station 102; network entity 1502). One or more of the illustrated operations may be omitted, reordered, or performed simultaneously. The method may allow a UE to utilize an existing PDU session when changing to a different network.

[0129] At 1302, a network entity may obtain a request to initiate connection establishment with a UE. For example, 1302 may be performed by connection component 199 of network entity 1502. The network entity may obtain a request to initiate connection establishment with the UE from the UE, as shown in any of those in conjunction with Figures 6 to 8 . The network entity may obtain a request to initiate connection establishment with the UE to initiate a network change from a first network to a second network. The network entity may be associated with the second network. The request to initiate connection establishment may include RRC connection establishment with a network entity associated with the second network.

[0130] At 1304, in response to initiating a network change, the network entity may obtain a registration request including a mobility registration indication, as shown in any of those in conjunction with Figures 6 to 8 . For example, 1304 may be performed by connection component 199 of network entity 1502. The network entity may obtain a registration request from the UE. In some aspects, the mobility registration indication may include a GUTI. The GUTI may include MCC, MNC, AMF area ID, AMF set ID, AMF pointer, and / or TMSI. In some aspects, the GUTI may include a GUAMI, where the GUAMI may be composed of at least MCC, MNC, AMF area ID, AMF set ID, and / or AMF pointer. In some aspects, the registration request may include a PDU session establishment indication indicating that the UE supports an existing PDU session establishment procedure. The PDU session establishment indication may include at least one of a tracking area identity (TAI) or an interworking indication. In some aspects, the registration request may include an interworking indication indicating support for an interworking feature. The UE may support an existing PDU session establishment procedure based on the interworking indication indicating support for the interworking feature.

[0131] At 1306, in response to an identity request provided to the UE, the network entity may obtain an identity indication from the UE. For example, 1306 may be performed by connection component 199 of network entity 1502. The network entity may obtain an identity indication in response to an identity request provided to the UE in response to a registration request, as shown in any of those in conjunction with Figures 6 to 8 . The network entity may provide an identity request to the UE in response to obtaining a registration request. In some aspects, the identity indication may include at least one of a SUPI, a SUCI, or an IMSI. Authentication of the UE by the second network may be based on the identity indication.

[0132] At 1308, the network entity may provide a registration acceptance indication. For example, 1308 may be performed by connection component 199 of network entity 1502. The network entity may provide a registration acceptance indication to the UE. The network entity may provide a registration acceptance indication in response to the transmission of the identity indication from the UE. The network entity may obtain an identity indication from the UE and provide a registration acceptance indication in response to the identity indication from the UE, as shown in any of those in conjunction withFigures 6 to 8 as shown in any of

[0133] At 1310, a network entity may obtain a PDU session establishment request. For example, 1310 may be performed by connection component 199 of network entity 1502. The network entity may obtain a PDU session establishment request from a UE. The network entity may obtain a PDU session establishment request indicating an existing PDU session from a first network for use on a second network, as shown in conjunction with Figures 6 to 8 any of

[0134] Figure 14 is a flowchart 1400 of a method of wireless communication. The method may be performed by a base station (e.g., base station 102; network entity 1502). One or more of the illustrated operations may be omitted, reordered, or performed simultaneously. The method may allow a UE to utilize an existing PDU session when changing to a different network.

[0135] At 1402, the network entity may obtain a request to initiate connection establishment with the UE. For example, 1402 may be performed by connection component 199 of network entity 1502. The network entity may obtain a request to initiate connection establishment with the UE, as shown in conjunction with Figures 6 to 8 any of

[0136] At 1404, in response to initiating a network change, the network entity may obtain a registration request including a mobility registration indication, as shown in conjunction with Figures 6 to 8as shown in any of the above. For example, 1404 may be performed by the connection component 199 of the network entity 1502. The network entity may obtain a registration request from the UE. In some aspects, the mobility registration indication may include a GUTI. The GUTI may include an MCC, an MNC, an AMF area ID, an AMF set ID, an AMF pointer, and / or a TMSI. In some aspects, the GUTI may include a GUAMI, where the GUAMI may be composed of at least an MCC, an MNC, an AMF area ID, an AMF set ID, and / or an AMF pointer. In some aspects, the registration request may include a PDU session establishment indication indicating that the UE supports the existing PDU session establishment process. The PDU session establishment indication may include at least one of a tracking area identity (TAI) or an interworking indication. In some aspects, the registration request may include an interworking indication indicating support for an interworking feature. The UE may support the existing PDU session establishment process based on the interworking indication indicating support for the interworking feature.

[0137] At 1406, the network entity may obtain an identity indication from the UE in response to an identity request provided to the UE. For example, 1406 may be performed by the connection component 199 of the network entity 1502. The network entity may obtain the identity indication in response to the identity request provided to the UE in response to the registration request, as shown in any of the above. The network entity may provide the identity request to the UE in response to obtaining the registration request. In some aspects, the identity indication may include at least one of a SUPI, a SUCI, or an IMSI. The second network may authenticate the UE based on the identity indication. Figures 6 to 8 as shown in any of the above. The network entity may provide the registration acceptance indication to the UE. The network entity may provide the registration acceptance indication in response to the transmission of the identity indication from the UE. The network entity may obtain the identity indication from the UE and provide the registration acceptance indication in response to the identity indication from the UE, as shown in any of the above. In some aspects, the registration acceptance indication may include an interworking indication indicating that the second network supports the existing PDU session establishment process.

[0138] At 1408, the network entity may provide a registration acceptance indication. For example, 1408 may be performed by the connection component 199 of the network entity 1502. The network entity may provide the registration acceptance indication to the UE. The network entity may provide the registration acceptance indication in response to the transmission of the identity indication from the UE. The network entity may obtain the identity indication from the UE and provide the registration acceptance indication in response to the identity indication from the UE, as shown in any of the above. In some aspects, the registration acceptance indication may include an interworking indication indicating that the second network supports the existing PDU session establishment process. Figures 6 to 8 as shown in any of the above. In some aspects, the registration acceptance indication may include an interworking indication indicating that the second network supports the existing PDU session establishment process.

[0139] At 1410, the network entity may obtain a PDU session establishment request. For example, 1410 may be performed by the connection component 199 of the network entity 1502. The network entity may obtain the PDU session establishment request from the UE. The network entity may obtain the PDU session establishment request indicating an existing PDU session from the first network for use on the second network, as shown in any of the above. Figures 6 to 8as shown in any of. The PDU session establishment request may include a request for an existing PDU session from the first network for use on the second network. In some aspects, the PDU session establishment request may be obtained from the UE based on the initiation of a network change. For example, the second network may use a different frequency range than the first network. In such a case, when making a network change from the first network to the second network, since the UE utilizes different frequency ranges, it may trigger the UE to send a PDU session establishment request. In some aspects, the second network may support the establishment of an existing PDU session based on an indication provided to the UE during authentication of the UE on the second network. For example, the indication provided to the UE during authentication may indicate whether the second network supports the establishment of an existing PDU session.

[0140] At 1412, the network entity may communicate with the UE. For example, 1412 may be performed by the connection component 199 of the network entity 1502. The network entity associated with the second network may communicate with the UE using the existing PDU session, as described in connection with Figures 6 to 8 any of. The network entity may communicate with the UE using the existing PDU session that was used when the UE communicated with the first network. When transitioning to the second network, the network entity using the existing PDU session on the second network to communicate with the UE allows the UE to maintain settings or parameters without having to update or request a new PDU session. For example, the UE using the existing PDU session on the second network allows the UE to maintain the same IP address, such that existing communications are not lost or dropped due to the handover to the second network.

[0141] Figure 15FIG. 1500 is a diagram illustrating an example of a hardware implementation for network entity 1502. Network entity 1502 may be a BS, a component of a BS, or may implement BS functionality. Network entity 1502 may include at least one of CU 1510, DU 1530, or RU 1540. For example, depending on the layer functionality handled by component 199, network entity 1502 may include CU 1510; both CU 1510 and DU 1530; each of CU 1510, DU 1530, and RU 1540; DU 1530; both DU 1530 and RU 1540; or RU 1540. CU 1510 may include CU processor 1512. CU processor 1512 may include on-chip memory 1512'. In some aspects, CU 1510 may also include additional memory module 1514 and communication interface 1518. CU 1510 communicates with DU 1530 via an intermediate link (such as the F1 interface). DU 1530 may include DU processor 1532. DU processor 1532 may include on-chip memory 1532'. In some aspects, DU 1530 may also include additional memory module 1534 and communication interface 1538. DU 1530 communicates with RU 1540 via a fronthaul link. RU 1540 may include RU processor 1542. RU processor 1542 may include on-chip memory 1542'. In some aspects, RU 1540 may also include additional memory module 1544, one or more transceivers 1546, antenna 1580, and communication interface 1548. RU 1540 communicates with UE 104. On-chip memories 1512', 1532', 1542' and additional memory modules 1514, 1534, 1544 may each be considered a computer-readable medium / memory. Each computer-readable medium / memory may be non-transitory. Each of processors 1512, 1532, 1542 is responsible for general processing, including executing software stored on the computer-readable medium / memory. The software, when executed by the corresponding processor, causes the processor to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the processor when executing the software.

[0142] As discussed above, component 199 is configured to obtain a request to initiate connection establishment with a UE to initiate a network change from a first network to a second network, where the network entity is associated with the second network; obtain a registration request including a mobility registration indication from the UE in response to the initiation of the network change; obtain an identity indication from the UE in response to an identity request provided to the UE in response to the registration request; provide a registration acceptance indication to the UE in response to the transmission of the identity indication; and obtain from the UE a PDU session establishment request indicating an existing PDU session from the first network for use on the second network. Component 199 may be within one or more processors of one or more of CU 1510, DU 1530, and RU 1540. Component 199 may be one or more hardware components specifically configured to perform the stated processes / algorithms, implemented by one or more processors configured to perform the stated processes / algorithms, stored in a computer-readable medium for implementation by one or more processors, or some combination thereof. Network entity 1502 may include a variety of components configured for various functions. In one configuration, network entity 1502 includes means for obtaining a request to initiate connection establishment with a UE to initiate a network change from a first network to a second network. The network entity is associated with the second network. The network entity includes means for obtaining a registration request including a mobility registration indication from the UE in response to initiating the network change. The network entity includes means for obtaining an identity indication from the UE in response to an identity request provided to the UE in response to the registration request. The network entity includes means for providing a registration acceptance indication to the UE in response to the transmission of the identity indication. The network entity includes means for obtaining from the UE a PDU session establishment request indicating an existing PDU session from the first network for use on the second network. The network entity further includes means for communicating with the UE using the existing PDU session. The means may be component 199 of network entity 1502 configured to perform the functions recited by the means. As described above, network entity 1502 may include TX processor 316, RX processor 370, and controller / processor 375. Thus, in one configuration, the means may be TX processor 316, RX processor 370, and / or controller / processor 375 configured to perform the functions recited by the means.

[0143] All aspects generally relate to the optimization of mobility between AMFs. Some aspects more specifically relate to a configuration that allows for supporting the interface between AMFs in cases where hardware from different vendors is used at least for AMFs between different networks. In some examples, a UE may provide identification information associated with the UE to allow for the establishment of an existing PDU session used on an existing network on a new network. For example, a UE may be connected to a first network and may initiate a network change to a second network such that an existing PDU session from the first network may be used by the UE on the second network. At least one advantage of the present disclosure is that a UE switching from a first network to a second network may utilize an existing PDU session utilized on the first network when switching to the second network. Using an existing PDU session on the second network or the newly connected network may allow the UE to maintain services utilizing the existing PDU session and not experience any service interruption. In another example, a UE may provide a GUTI to the second network or the new network. The advantage of providing a GUTI to the new network is that the new network may utilize the GUTI to authenticate the identity of the UE instead of rejecting a registration request. In yet another example, a registration request may include an interworking indication indicating support for an interworking feature. Supporting the interworking feature may indicate to the new network that the UE supports the existing PDU session establishment process.

[0144] It should be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is illustrative of example methods. It should be understood that based on design preferences, the specific order or hierarchy of the blocks in the process / flowchart may be rearranged. Further, some blocks may be combined or omitted. The appended method claims present the elements of the various blocks in a sample order, but are not limited to the specific order or hierarchy presented.

[0145] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. 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. Thus, the claims are not limited to the aspects described herein, but should be accorded the full scope consistent with the language of the claims. References to elements in the singular form do not, unless specifically stated otherwise, mean "one and only one" but rather "one or more." Terms such as "if," "when," and "while" do not denote a direct temporal relationship or reaction. That is, these phrases, such as "when...," do not mean an immediate action in response to the occurrence of an action or during the occurrence of an action, but simply imply that if the condition is met, the action will occur, without requiring a specific or immediate time limitation for the action to occur. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or having an advantage over other aspects. Unless specifically stated otherwise, the term "some" refers to one or more. Combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "any combination of A, B, C, or any of them," including any combination of A, B, and / or C, may include multiple A's, multiple B's, or multiple C's. Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "any combination of A, B, C, or any of them" may be only A, only B, only C, A and B, A and C, B and C, or A and B and C, where any such combination may include one or more members of A, B, or C. A set should be construed as a collection of elements, where the number of elements is one or more. Thus, for a set of X, X will include one or more elements. If a first device receives data from or sends data to a second device, the data may be received / sent directly between the first device and the second device, or indirectly between the first device and the second device through a collection of devices. A device configured to "output" data (such as, send, signal, or message) may, for example, send the data with a transceiver, or may convey the data to a device that sends the data. A device configured to "obtain" data (such as, send, signal, or message) may, for example, receive the data with a transceiver, or may obtain the data from a device that receives the data. All structural and functional equivalents of the elements of the various aspects described throughout this disclosure that are known or later will be known to those of ordinary skill in the art are expressly incorporated herein by reference and are covered by the claims.Moreover, nothing disclosed herein is intended to be dedicated to the public, whether or not such disclosure is expressly recited in the claims. The words "module", "mechanism", "element", "device", etc. shall not be used as a substitute for the word "component". Accordingly, no claim element shall be construed as a means-plus-function unless the element is expressly recited using the phrase "means for".

[0146] As used herein, the phrase "based on" shall not be construed to refer to a closed set of information, one or more conditions, one or more factors, etc. In other words, the phrase "based on A" (where "A" can be information, a condition, a factor, etc.) shall be construed as "at least based on A", unless otherwise specifically recited.

[0147] The following aspects are merely illustrative and may be combined with other aspects or teachings described herein without limitation.

[0148] Aspect 1 is a method for wireless communication at a UE, the method comprising: initiating establishment of a connection with a second network to initiate a network change from a first network to the second network; sending, in response to the initiation of the network change, a registration request including a mobility registration indication to the second network; sending, in response to an identity request from the second network in response to the registration request, an identity indication to the second network; receiving, in response to the sending of the identity indication, a registration acceptance indication from the second network; and sending, to the second network, a PDU session establishment request indicating an existing PDU session from the first network for use on the second network.

[0149] Aspect 2 is the method according to aspect 1, the method further comprising: the connection establishment includes establishment of an RRC connection with the second network.

[0150] Aspect 3 is the method according to any one of aspects 1 and 2, the method further comprising: the mobility registration indication includes a GUTI.

[0151] Aspect 4 is the method according to any one of aspects 1 to 3, the method further comprising: the GUTI includes an MCC, an MNC, an AMF area ID, an AMF set ID, an AMF pointer, and a TMSI, wherein the GUTI includes a GUAMI, and wherein the GUAMI consists of at least the MCC, the MNC, the AMF area ID, the AMF set ID, and the AMF pointer.

[0152] Aspect 5 is the method according to any one of aspects 1 to 4, the method further comprising: the identity indication includes at least one of a SUPI, a SUCI, or an IMSI.

[0153] Aspect 6 is the method according to any one of Aspects 1 to 5, the method further comprising: the UE is authenticated by the second network based on the identity indication.

[0154] Aspect 7 is the method according to any one of Aspects 1 to 6, the method further comprising: the PDU session establishment request is sent based on the initiation of the network change, wherein the second network uses a frequency range different from that of the first network, and wherein the PDU session establishment request is triggered by using the different frequency range when the network change to the second network occurs.

[0155] Aspect 8 is the method according to any one of Aspects 1 to 7, the method further comprising: determining that the second network supports establishing the existing PDU session at the second network based on an indication received during the authentication of the UE by the second network.

[0156] Aspect 9 is the method according to any one of Aspects 1 to 8, the method further comprising: the registration request includes a PDU session establishment indication indicating that the UE supports the existing PDU session establishment process, wherein the PDU session establishment indication includes at least one of a TAI or an interworking indication.

[0157] Aspect 10 is the method according to any one of Aspects 1 to 9, the method further comprising: communicating with the second network using the existing PDU session.

[0158] Aspect 11 is the method according to any one of Aspects 1 to 10, the method further comprising: the registration request includes an interworking indication indicating support for interworking features, and the UE supports the existing PDU session establishment process based on the interworking indication indicating support for the interworking features.

[0159] Aspect 12 is the method according to any one of Aspects 1 to 11, the method further comprising: the registration acceptance indication includes an interworking indication indicating that the second network supports the existing PDU session establishment process.

[0160] Aspect 13 is a device for wireless communication at a UE, the device comprising: at least one processor, the at least one processor coupled to a memory; and at least one transceiver, the at least one processor being configured to implement any one of Aspects 1 to 12.

[0161] Aspect 14 is a device for wireless communication at a UE, the device comprising components for implementing any one of Aspects 1 to 12.

[0162] Aspect 15 is a computer-readable medium storing computer-executable code, where the code, when executed by a processor, causes the processor to implement any one of Aspects 1 to 12.

[0163] Aspect 16 is a method for wireless communication at a network entity, the method comprising: obtaining a request to initiate a connection establishment with a UE to initiate a network change from a first network to a second network, where the network entity is associated with the second network; obtaining, in response to the initiation of the network change, a registration request from the UE comprising a mobility registration indication; obtaining, in response to an identity request provided to the UE in response to the registration request, an identity indication from the UE; providing a registration acceptance indication to the UE in response to the sending of the identity indication; and obtaining, from the UE, a PDU session establishment request indicating an existing PDU session from the first network for use on the second network.

[0164] Aspect 17 is the method according to Aspect 16, the method further comprising: the request to initiate the connection establishment comprises an RRC connection establishment with the network entity associated with the second network.

[0165] Aspect 18 is the method according to any one of Aspects 16 and 17, the method further comprising: the mobility registration indication comprises a GUTI.

[0166] Aspect 19 is the method according to any one of Aspects 16 to 18, the method further comprising: the GUTI comprises an MCC, an MNC, an AMF area ID, an AMF set ID, an AMF pointer, and a TMSI, where the GUTI comprises a GUAMI, where the GUAMI is composed of at least the MCC, the MNC, the AMF area ID, the AMF set ID, and the AMF pointer.

[0167] Aspect 20 is the method according to any one of Aspects 16 to 19, the method further comprising: the identity indication comprises at least one of a SUPI, a SUCI, or an IMSI.

[0168] Aspect 21 is the method according to any one of Aspects 16 to 20, the method further comprising: authenticating the UE is based on the identity indication.

[0169] Aspect 22 is the method according to any one of Aspects 16 to 21, the method further comprising: the PDU session establishment request is obtained based on the initiation of the network change, where the PDU session establishment request is obtained based on a frequency range different from the frequency range utilized on the first network for utilization on the second network.

[0170] Aspect 23 is the method according to any one of aspects 16 to 22, the method further comprising: the second network supports establishing the existing PDU session based on an indication provided to the UE during authentication of the UE in the second network.

[0171] Aspect 24 is the method according to any one of aspects 16 to 23, the method further comprising: the registration request includes a PDU session establishment indication indicating that the UE supports the existing PDU session establishment procedure, wherein the PDU session establishment indication includes at least one of a TAI or an interworking indication.

[0172] Aspect 25 is the method according to any one of aspects 16 to 24, the method further comprising: communicating with the UE using the existing PDU session.

[0173] Aspect 26 is the method according to any one of aspects 16 to 25, the method further comprising: the registration request includes an interworking indication indicating support for interworking features, wherein the UE supports the existing PDU session establishment procedure based on the interworking indication indicating support for the interworking features.

[0174] Aspect 27 is the method according to any one of aspects 16 to 26, the method further comprising: the registration acceptance indication includes an interworking indication indicating that the second network supports the existing PDU session establishment procedure.

[0175] Aspect 28 is an apparatus for wireless communication at a network entity, the apparatus comprising: at least one processor, the at least one processor coupled to a memory; and at least one transceiver, the at least one processor configured to implement any one of aspects 16 to 27.

[0176] Aspect 29 is an apparatus for wireless communication at a network entity, the apparatus comprising components for implementing any one of aspects 16 to 27.

[0177] Aspect 30 is a computer-readable medium storing computer-executable code, wherein the code, when executed by a processor, causes the processor to implement any one of aspects 16 to 27.

Claims

1. An apparatus for wireless communication at a user equipment (UE), the apparatus comprising: a memory; and at least one processor coupled to the memory and configured, at least in part based on information stored in the memory, to: initiate connection establishment with a second network to initiate a network change from a first network to the second network; send a registration request including a mobility registration indication to the second network in response to the initiation of the network change; send an identity indication to the second network in response to an identity request from the second network in response to the registration request; receive a registration acceptance indication from the second network in response to the sending of the identity indication; and send a PDU session establishment request to the second network indicating an existing packet data unit (PDU) session from the first network for use on the second network.

2. The apparatus according to claim 1, the apparatus further comprising a transceiver coupled to the at least one processor.

3. The apparatus according to claim 1, wherein the connection establishment includes radio resource control (RRC) connection establishment with the second network.

4. The apparatus according to claim 1, wherein the mobility registration indication includes a globally unique temporary identifier (GUTI).

5. The apparatus according to claim 4, wherein the GUTI includes a mobile country code (MCC), a mobile network code (MNC), an access and mobility management function (AMF) area identifier (ID), an AMF set ID, an AMF pointer, and a temporary mobile subscriber identity (TMSI), wherein the GUTI includes a globally unique AMF ID (GUAMI), wherein the GUAMI is at least composed of the MCC, the MNC, the AMF area ID, the AMF set ID, and the AMF pointer.

6. The apparatus according to claim 1, wherein the identity indication includes at least one of a subscription permanent identifier (SUPI), a subscription concealed identifier (SUCI), or an international mobile subscriber identity (IMSI).

7. The apparatus according to claim 1, wherein the UE is authenticated by the second network based on the identity indication.

8. The apparatus according to claim 1, wherein the PDU session establishment request is sent based on the initiation of the network change, wherein the second network uses a different frequency range from the first network, and wherein the PDU session establishment request is triggered by the utilization of the different frequency range when the network change to the second network occurs.

9. The apparatus according to claim 1, wherein the at least one processor is configured to determine that the second network supports establishment of the existing PDU session at the second network based on an indication received during authentication of the UE by the second network.

10. The apparatus according to claim 1, wherein the registration request includes a PDU session establishment indication indicating that the UE supports an existing PDU session establishment procedure, and the PDU session establishment indication includes at least one of a tracking area identity (TAI) or an interworking indication.

11. The apparatus according to claim 1, wherein the at least one processor is configured to: communicate with the second network using the existing PDU session.

12. The apparatus according to claim 1, wherein the registration request includes an interworking indication indicating support for an interworking feature, and the UE supports an existing PDU session establishment procedure based on the interworking indication indicating support for the interworking feature.

13. The apparatus according to claim 1, wherein the registration acceptance indication includes an interworking indication indicating that the second network supports an existing PDU session establishment procedure.

14. A method for wireless communication at a user equipment (UE), the method comprising: initiating a connection establishment with a second network to initiate a network change from a first network to the second network; sending a registration request including a mobility registration indication to the second network in response to the initiation of the network change; sending an identity indication to the second network in response to an identity request from the second network in response to the registration request; receiving a registration acceptance indication from the second network in response to the sending of the identity indication; and sending a PDU session establishment request indicating an existing packet data unit (PDU) session from the first network for use on the second network to the second network.

15. The method according to claim 14, the method further comprising: communicating with the second network using the existing PDU session.

16. An apparatus for wireless communication at a network entity, the apparatus comprising: a memory; and at least one processor coupled to the memory, and at least partially based on information stored in the memory, the at least one processor is configured to: obtain a request to initiate a connection establishment with a user equipment (UE) to initiate a network change from a first network to a second network, wherein the network entity is associated with the second network; obtain a registration request including a mobility registration indication from the UE in response to the initiation of the network change; obtain an identity indication from the UE in response to an identity request provided to the UE in response to the registration request; provide a registration acceptance indication to the UE in response to the sending of the identity indication; and obtain a PDU session establishment request from the UE indicating an existing packet data unit (PDU) session from the first network for use on the second network.

17. The apparatus according to claim 16, the apparatus further comprising a transceiver coupled to the at least one processor.

18. The apparatus according to claim 16, wherein the request to initiate the connection establishment includes a radio resource control (RRC) connection establishment with the network entity associated with the second network.

19. The apparatus according to claim 16, wherein the mobility registration indication includes a Globally Unique Temporary Identifier (GUTI).

20. The apparatus according to claim 19, wherein the GUTI includes a Mobile Country Code (MCC), a Mobile Network Code (MNC), an Access and Mobility Management Function (AMF) area identifier (ID), an AMF set ID, an AMF pointer, and a Temporary Mobile Subscriber Identity (TMSI), wherein the GUTI includes a Globally Unique AMF ID (GUAMI), and wherein the GUAMI is composed of at least the MCC, the MNC, the AMF area ID, the AMF set ID, and the AMF pointer.

21. The apparatus according to claim 16, wherein the identification indication includes at least one of a Subscription Permanent Identifier (SUPI), a Subscription Concealed Identifier (SUCI), or an International Mobile Subscriber Identity (IMSI).

22. The apparatus according to claim 16, wherein the authentication of the UE is based on the identification indication.

23. The apparatus according to claim 16, wherein the PDU session establishment request is obtained based on the initiation of the network change, and wherein the PDU session establishment request is obtained based on a frequency range different from the frequency range utilized on the first network and utilized on the second network.

24. The apparatus according to claim 16, wherein the second network supports the establishment of the existing PDU session based on an indication provided to the UE during the authentication of the UE on the second network.

25. The apparatus according to claim 16, wherein the registration request includes a PDU session establishment indication indicating that the UE supports the existing PDU session establishment process, and wherein the PDU session establishment indication includes at least one of a Tracking Area Identity (TAI) or an interworking indication.

26. The apparatus according to claim 16, wherein the at least one processor is configured to: communicate with the UE using the existing PDU session.

27. The apparatus according to claim 16, wherein the registration request includes an interworking indication indicating support for an interworking feature, and wherein the UE supports the existing PDU session establishment process based on the interworking indication indicating support for the interworking feature.

28. The apparatus according to claim 16, wherein the registration acceptance indication includes an interworking indication indicating that the second network supports the existing PDU session establishment process.

29. A method for wireless communication at a network entity, the method comprising: obtaining a request to initiate a connection establishment with a User Equipment (UE) to initiate a network change from a first network to a second network, wherein the network entity is associated with the second network; obtaining a registration request including a mobility registration indication from the UE in response to the initiation of the network change; obtaining an identification indication from the UE in response to an identification request provided to the UE in response to the registration request; providing a registration acceptance indication to the UE in response to the sending of the identification indication; and Obtain a PDU session establishment request for an existing packet data unit (PDU) session from the first network for use on the second network from the UE.

30. The method according to claim 29, the method further comprising: Communicating with the UE using the existing PDU session.

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