Connected call recovery

Abstract

A method of wireless communication includes initiating a handover of a first call from a source network to a target network. The first call is associated with first header information. The method also includes receiving a message indicating that an Internet Protocol (IP) address is changed to a new IP address during the handover. The method also includes releasing a resource associated with the first call in response to receiving the message. The method includes registering the new IP address with the target network, and initiating a second call using the first header information. The method also includes replacing the first call with the second call and the new IP address.

Description

Technical Field

[0001] This application claims priority to U.S. patent application Ser. No. 17 / 871,703, filed on July 22, 2022, entitled “CONNECTED CALL RECOVERY,” the disclosure of which is expressly incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates generally to wireless communications and, more particularly, to connected call recovery during handoff from one wireless network to another. Background Art

[0004] Wireless communication systems are widely deployed to provide various telecommunication services such as telephone, video, data, messaging, and broadcasting. Typical wireless communication systems may employ multiple access technologies that can support communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). 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, time division synchronous code division multiple access (TD-SCDMA) systems, and long term evolution (LTE). LTE / LTE Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard issued by the Third Generation Partnership Project (3GPP). Narrowband (NB) Internet of Things (IoT) and enhanced machine type communication (eMTC) are sets of enhancements to LTE for machine type communication.

[0005] A wireless communication network may include multiple base stations (BSs) that may support communications for multiple user equipments (UEs). User equipments (UEs) may communicate with base stations (BSs) via downlinks and uplinks. Downlinks (or forward links) refer to the communication link from a BS to a UE, while uplinks (or reverse links) refer to the communication link from a UE to a BS. As will be described in more detail, a BS may be referred to as a Node B, an evolved Node B (eNB), a gNB, an access point (AP), a radio head, a transmit and receive point (TRP), a new radio (NR) BS, a 5G Node B, etc.

[0006] The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different user equipment to communicate at city, country, region, and even global levels. New Radio (NR) (which may also be referred to as 5G) is an enhancement set of the LTE mobile standard released by the Third Generation Partnership Project (3GPP). NR is designed to better integrate with other open standards by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and using orthogonal frequency division multiplexing (OFDM) (CP-OFDM) with cyclic prefix (CP) on the downlink (DL), using CP-OFDM and / or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), and supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation, so as to better support mobile broadband Internet access. Summary of the invention

[0007] In various aspects of the present disclosure, a wireless communication method includes initiating a handover of a first call from a source network to a target network. The first call is associated with first header information. The method also includes receiving a message indicating that an Internet Protocol (IP) address is changed to a new IP address during the handover. The method also includes releasing resources associated with the first call in response to receiving the message. The method includes registering the new IP address with the target network, and initiating a second call using the first header information. The method also includes replacing the first call with the second call and the new IP address.

[0008] In various aspects of the present disclosure, a method for wireless communication by a network entity includes receiving a request to handover a first call from a source network to a target network. The first call is associated with first header information. The method also includes sending a message indicating that an Internet Protocol (IP) address is changed to a new IP address during the handover. The method also includes releasing resources associated with the first call. The method includes registering the new IP address, and receiving signaling to initiate a second call using the first header information. The method also includes replacing the first call with the second call and the new IP address.

[0009] Other aspects of the present disclosure relate to an apparatus. The apparatus has a memory and one or more processors coupled to the memory. The processor is configured to initiate a handover of a first call from a source network to a target network. The first call is associated with first header information. The processor is also configured to receive a message indicating that an Internet Protocol (IP) address is changed to a new IP address during the handover. The processor is also configured to release resources associated with the first call in response to receiving the message. The processor is configured to register a new IP address with the target network and initiate a second call using the first header information. The processor is also configured to replace the first call with the second call and the new IP address.

[0010] Other aspects of the present disclosure relate to an apparatus. The apparatus has a memory and one or more processors coupled to the memory. The processor is configured to receive a request to handover a first call from a source network to a target network. The first call is associated with first header information. The processor is further configured to send a message indicating that an Internet Protocol (IP) address is changed to a new IP address during the handover. The processor is further configured to release resources associated with the first call. The processor is configured to register the new IP address and receive signaling to initiate a second call using the first header information. The processor is further configured to replace the first call with the second call and the new IP address.

[0011] Aspects generally include methods, apparatus, systems, computer program products, non-transitory computer readable media, user equipment, base stations, wireless communication devices, and processing systems as generally described with reference to and as illustrated in the accompanying drawings and description.

[0012] The features and technical advantages of examples according to the present disclosure have been outlined quite broadly above so that the following specific embodiments may be better understood. Additional features and advantages will be described. The disclosed concepts and specific examples may be easily used as a basis for modifying or designing other structures for achieving the same purpose of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. The characteristics of the disclosed concepts, both in terms of their organization and method of operation, and the associated advantages will be better understood by considering the following description in conjunction with the accompanying drawings. Each of the figures in the accompanying drawings is provided for the purpose of illustration and description and not as a definition of the limitations of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order that the features of the present disclosure may be understood in detail, a more specific description may be made with reference to various aspects, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only certain aspects of the present disclosure and therefore should not be considered as limiting the scope thereof, as the description may allow for other equally effective aspects. The same reference numerals in different drawings may identify the same or similar elements.

[0014] Figure 1 is a block diagram conceptually illustrating an example of a wireless communication network in accordance with various aspects of the present disclosure.

[0015] Figure 2 is a block diagram conceptually illustrating an example of a base station communicating with a user equipment (UE) in a wireless communication network according to various aspects of the present disclosure.

[0016] Figure 3 is a block diagram illustrating an example decomposed base station architecture in accordance with aspects of the present disclosure.

[0017] Figure 4 is a timing diagram illustrating a handover failure due to an Internet Protocol (IP) address change.

[0018] Figure 5 is a timing diagram illustrating an example of connected call resumption after an IP address change in accordance with aspects of the present disclosure.

[0019] Figure 6 is a flow chart illustrating an example process performed, for example, by a user equipment (UE) according to various aspects of the present disclosure.

[0020] Figure 7 is a flow chart illustrating an example process, for example, performed by a network device, according to various aspects of the present disclosure. DETAILED DESCRIPTION

[0021] The various aspects of the present disclosure are described more fully below with reference to the accompanying drawings. However, the present disclosure can be embodied in many different forms, and should not be interpreted as being limited to any specific structure or function presented throughout the present disclosure. Instead, these aspects are provided so that the present disclosure will be thorough and complete, and the scope of protection of the present disclosure will be fully conveyed to those skilled in the art. Based on the teachings, those skilled in the art should recognize that the scope of the present disclosure is intended to cover any aspect of the present disclosure, whether the aspect is implemented independently of any other aspect of the present disclosure or implemented in combination with any other aspect. For example, a device or a method can be implemented using any number of aspects described. In addition, the scope of the present disclosure is intended to cover such devices or methods that are practiced using other structures, functionality, or structures and functionality as a supplement to the various aspects of the present disclosure described or in addition. It should be understood that any aspect of the present disclosure disclosed can be embodied by one or more elements of the claims.

[0022] Several aspects of telecommunication systems will now be presented with reference to various devices and techniques. These devices and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented using hardware, software, or a combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0023] It should be noted that although various aspects may be described using terms commonly associated with 5G and later wireless technologies, various aspects of the present disclosure may be applied in communication systems based on other generations (such as and including 3G and / or 4G technologies).

[0024] In existing technologies for mobile communications, such as using telematics, when the Internet Protocol (IP) address assigned to the user equipment (UE) changes during handover to another network, the user equipment (UE) ends the call. This handover can be part of an evolved packet data gateway (EPDG) handover from a fifth generation (5G) new radio (NR) network to an IP multimedia subsystem (IMS) network, such as a wireless local area network (WLAN) (e.g., 802.11 WiFi), and vice versa. These handover procedures have many indoor use cases, for example, where the UE is handed over from a cellular network to a WiFi network when the cellular signal does not reach all parts of a building with good WiFi coverage. Handovers may occur when cellular network connectivity is lost, for example due to poor cell conditions in an area with strong WiFi coverage. Handover interruptions caused by IP address changes negatively affect the user experience because such handovers occur implicitly without user intervention, resulting in dropped calls due to reasons unknown to the user.

[0025] According to aspects of the present disclosure, a process is introduced for a UE that experiences network impairment to release a call connected to a remote UE. The new process then restores the call by establishing a new call to replace the dropped / released call. The new call is established using a new invite message to the remote UE. The new invite message includes replacement header information.

[0026] Aspects of the present disclosure are beneficial when a UE is registered with an NR or Long Term Evolution (LTE) network and is also connected to a WLAN access point (AP). In this example, a user makes a voice call over the NR network and the call is connected to the called party. During the call, when the call is handed over to the WLAN due to handover criteria, the network reports an IP address change event as part of the handover procedure. Since the call has been established with a different IP address and the remote UE cannot be updated with the new IP address without completing the registration procedure with the new IP address, the call will be immediately dropped.

[0027] To address these issues, aspects of the present disclosure clear the call locally. That is, the calling UE releases resources associated with the call. In some implementations, a custom reason may be provided to a user interface (UI) to notify the user that the call is in a reconnecting state due to network impairment. The calling UE also stores certain header information associated with the first call and registers a new IP address with the network. Once registration is complete, the calling UE transmits an INVITE to the remote UE to replace certain header information associated with the original call as part of a replacement header, thereby enabling the remote UE to resume the previous call.

[0028] Figure 1 1 is a diagram illustrating a network 100 in which various aspects of the present disclosure may be practiced. The network 100 may be a 5G or NR network, or some other wireless network (such as an LTE network). The wireless network 100 may include a plurality of BSs 110 (shown as BSs 110a, BSs 110b, BSs 110c, and BSs 110d) and other network entities. A BS is an entity that communicates with a user equipment (UE), and may also be referred to as a base station, an NR BS, a Node B, a gNB, a 5G Node B, an access point, a transmission and reception point (TRP), a network node, a network entity, etc. A base station may be implemented as an aggregated base station, a decomposed base station, an integrated access and backhaul (IAB) node, a relay node, a side link node, etc. A base station may be implemented in an aggregated or monolithic base station architecture, or alternatively, in a decomposed base station architecture, and may include one or more of a central unit (CU), a distributed unit (DU), a radio unit (RU), a near real-time (near RT) RAN intelligent controller (RIC), or a non-real-time (non-RT) RIC.

[0029] Each BS can provide communication coverage for a specific geographical area. In 3GPP, the term "cell" can refer to the coverage area of ​​a BS and / or a BS subsystem serving the coverage area, depending on the context in which the term is used.

[0030] A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and / or another type of cell. A macro cell may cover a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access by UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG)). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In Figure 1 In the example shown in , BS 110a may be a macro BS for macro cell 102a, BS 110b may be a pico BS for pico cell 102b, and BS 110c may be a femto BS for femto cell 102c. A BS may support one or more (e.g., three) cells. The terms "eNB", "base station", "NRBS", "gNB", "AP", "Node B", "5G NB", "TRP", and "cell" may be used interchangeably.

[0031] In some aspects, the cell need not be stationary, and the geographic area of ​​the cell may move depending on the location of the mobile BS. In some aspects, the BSs may be interconnected with each other and / or to one or more other BSs or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces (such as direct physical connections, virtual networks, etc.) using any suitable transport network.

[0032] The wireless network 100 may also include a relay station. A relay station is an entity that can receive transmissions of data from an upstream station (e.g., a BS or a UE) and transmit the transmissions of the data to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that can relay transmissions for other UEs. Figure 1 In the example shown in FIG. 1 , a relay station 110 d may communicate with a macro BS 110 a and a UE 120 d to facilitate communication between the BS 110 a and the UE 120 d. A relay station may also be referred to as a relay BS, a relay base station, a relay, or the like.

[0033] The wireless network 100 may be a heterogeneous network including different types of BSs (e.g., macro BSs, pico BSs, femto BSs, relay BSs, etc.). These different types of BSs may have different transmit power levels, different coverage areas, and different effects on interference in the wireless network 100. For example, a macro BS may have a high transmit power level (e.g., 5 watts to 40 watts), while a pico BS, a femto BS, and a relay BS may have a lower transmit power level (e.g., 0.1 watt to 2 watts).

[0034] As an example, BSs 110 (shown as BSs 110a, BSs 110b, BSs 110c, and BSs 110d) and core network 130 may exchange communications via backhaul links 132 (e.g., S1, etc.). Base stations 110 may communicate with each other directly or indirectly (e.g., through core network 130) over other backhaul links (e.g., X2, etc.).

[0035] The core network 130 may be an evolved packet core (EPC), which may include at least one mobile management entity (MME), at least one serving gateway (S-GW), and at least one packet data network (PDN) gateway (P-GW). The MME may be a control node that handles signaling between the UE 120 and the EPC. All user IP packets may be delivered through the S-GW, which itself may be connected to the P-GW. The P-GW may provide IP address allocation and other functions. The P-GW may be connected to the IP services of the network operator. The operator's IP services may include the Internet, the intranet, the IP multimedia subsystem (IMS), and the packet switched (PS) streaming media services.

[0036] The core network 130 may provide user authentication, access authorization, tracking, IP connectivity, and other access, routing, or mobility functions. One or more of the base stations 110 or access node controllers (ANCs) may interface with the core network 130 via a backhaul link 132 (e.g., S1, S2, etc.) and may perform radio configuration and scheduling for communication with the UE 120. In some configurations, the various functions of each access network entity or base station 110 may be distributed across various network devices (e.g., radio heads and access network controllers) or merged into a single network device (e.g., base station 110).

[0037] UE 120 (e.g., 120a, 120b, 120c) may be dispersed throughout the wireless network 100, and each UE may be stationary or mobile. UE may also be referred to as an access terminal, terminal, mobile station, subscriber unit, station, etc. UE may be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, a biometric sensor / device, a wearable device (smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet)), an entertainment device (e.g., a music or video device or a satellite radio), a component or sensor of a vehicle, a smart meter / sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device configured to communicate via a wireless or wired medium.

[0038] One or more UEs 120 may establish a protocol data unit (PDU) session for a network slice. In some cases, the UE 120 may select a network slice based on an application or subscription service. By having different network slices serve different applications or subscriptions, the UE 120 may improve its resource utilization in the wireless network 100 while also meeting the performance specifications of the individual applications of the UE 120. In some cases, the network slice used by the UE 120 may be determined by an AMF (AMF) associated with one or both of the base station 110 or the core network 130. Figure 1 In addition, session management of the network slice may be performed by an access and mobility management function (AMF).

[0039] UE 120 may include a call recovery module 140. For simplicity, only one UE 120d is shown to include the call recovery module 140. The call recovery module 140 may initiate a handover of a first call from a source network to a target network. The first call is associated with the first header information. The call recovery module 140 may also receive a message indicating that an Internet Protocol (IP) address is changed to a new IP address during the handover. The call recovery module 140 may also release resources associated with the first call in response to receiving the message and register a new IP address with the target network. The call recovery module 140 may also initiate a second call using the first header information. The call recovery module 140 may also replace the first call with the second call and the new IP address.

[0040] The core network 130, the base station 110, a component of the base station 110, or another network device such as a wireless local area network (WLAN) access point may include a call recovery module 138. For simplicity, only one base station 110 is shown to include a call recovery module 138. The call recovery module 138 may receive a request to hand over a first call from a source network to a target network, the first call being associated with the first header information. The call recovery module 138 may also send a message indicating that an Internet Protocol (IP) address is changed to a new IP address during the handover. The call recovery module 138 may also release resources associated with the first call. The call recovery module 138 may also register a new IP address and receive signaling for initiating a second call using the first header information. The call recovery module 138 may also replace the first call with the second call and the new IP address.

[0041] Some UEs may be considered as machine type communication (MTC) or evolved or enhanced machine type communication (eMTC) UEs. For example, MTC and eMTC UEs include robots, drones, remote devices, sensors, meters, monitors, location tags, etc. that can communicate with a base station, another device (e.g., a remote device), or some other entity. A wireless node may provide connectivity to or to a network (e.g., a wide area network (such as the Internet) or a cellular network), for example, via a wired or wireless communication link. Some UEs may be considered as Internet of Things (IoT) devices and / or may be implemented as NB-IoT (narrowband Internet of Things) devices. Some UEs may be considered as user premises equipment (CPE). UE 120 may be included in a housing that houses components of UE 120 (such as a processor component, a memory component, etc.).

[0042] Generally speaking, any number of wireless networks can be deployed in a given geographic area. Each wireless network can support a specific radio access technology (RAT) and can operate on one or more frequencies. RAT can also be referred to as radio technology, air interface, etc. Frequency can also be referred to as carrier, frequency channel, etc. In a given geographic area, each frequency can support a single RAT to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks can be deployed.

[0043] In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly (e.g., without using base station 110 as an intermediary to communicate with each other) using one or more sidelink channels. For example, UE 120 may communicate using peer-to-peer (P2P) communication, device-to-device (D2D) communication, vehicle-to-everything (V2X) protocols (e.g., which may include vehicle-to-vehicle (V2V) protocols, vehicle-to-infrastructure (V2I) protocols, etc.), mesh networks, etc. In this case, UE 120 may perform scheduling operations, resource selection operations, and / or other operations described elsewhere herein performed by base station 110. For example, base station 110 may configure UE 120 via downlink control information (DCI), radio resource control (RRC) signaling, medium access control-control element (MAC-CE), or via system information (e.g., system information block (SIB)).

[0044] As pointed out above, Figure 1 This is provided as an example only. Other examples can be found in the reference Figure 1 The examples described are different.

[0045] Figure 2 A block diagram of a design 200 of a base station 110 and a UE 120 is shown, which may be Figure 1 One for each base station and one for each UE in the base station 110. Base station 110 may be equipped with T antennas 234a through 234t, and UE 120 may be equipped with R antennas 252a through 252r, where in general T≥1 and R≥1.

[0046] At the base station 110, the transmit processor 220 may receive data for one or more UEs from the data source 212, select one or more modulation and coding schemes (MCS) for each UE based at least in part on a channel quality indicator (CQI) received from the UE, process (e.g., encode and modulate) the data for the UE based at least in part on the MCS selected for each UE, and provide data symbols for all UEs. Reducing the MCS lowers throughput but increases the reliability of transmission. The transmit processor 220 may also process system information (e.g., for semi-static resource allocation information (SRPI), etc.) and control information (e.g., CQI requests, grants, upper layer signaling, etc.), and provide overhead symbols and control symbols. The transmit processor 220 may also generate reference symbols for reference signals (e.g., cell-specific reference signals (CRS)) and synchronization signals (e.g., primary synchronization signals (PSS) and secondary synchronization signals (SSS)). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., pre-coding) on ​​data symbols, control symbols, overhead symbols, and / or reference symbols where applicable, and may provide T output symbol streams to T modulators (MOD) 232a to 232t. Each modulator 232 may process a corresponding output symbol stream (e.g., for orthogonal frequency division multiplexing (OFDM) or the like) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The T downlink signals from modulators 232a to 232t may be transmitted via T antennas 234a to 234t, respectively. According to various aspects described in more detail below, position coding may be used to generate synchronization signals to convey additional information.

[0047] At the UE 120, antennas 252a to 252r may receive downlink signals from the base station 110 and / or other base stations, and may provide received signals to demodulators (DEMODs) 254a to 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) the received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. The MIMO detector 256 may obtain received symbols from all R demodulators 254a to 254r, perform MIMO detection on the received symbols (if applicable), and provide detected symbols. The receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for the UE 120 to the data sink 260, and provide decoded control information and system information to the controller / processor 280. The channel processor may determine reference signal received power (RSRP), received signal strength indicator (RSSI), reference signal received quality (RSRQ), channel quality indicator (CQI), etc. In some aspects, one or more components of UE 120 may be included in a housing.

[0048] On the uplink, at the UE 120, a transmit processor 264 may receive data from a data source 262 and control information (e.g., for reports including RSRP, RSSI, RSRQ, CQI, etc.) from a controller / processor 280 and process the data and control information. The transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from the transmit processor 264 may be pre-decoded by a TX MIMO processor 266 (if applicable), further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM, CP-OFDM, etc.), and transmitted to the base station 110. At the base station 110, uplink signals from the UE 120 and other UEs may be received by the antenna 234, processed by the demodulator 254, detected by the MIMO detector 236 (if applicable), and further processed by the receive processor 238 to obtain decoded data and control information transmitted by the UE 120. The receive processor 238 may provide the decoded data to the data sink 239 and the decoded control information to the controller / processor 240. The base station 110 may include a communication unit 244 and communicate with the core network 130 via the communication unit 244. The core network 130 may include a communication unit 294, a controller / processor 290, and a memory 292.

[0049] The controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2Any other components of the base station 110 may perform one or more techniques related to connected call recovery, as described in more detail elsewhere. For example, the controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2 Any other component of the can perform or direct e.g. Figures 5 to 7 The processes and / or operations of other processes as described herein. Memory 242 and memory 282 may store data and program codes for base station 110 and UE 120, respectively. Scheduler 246 may schedule UEs for data transmission on the downlink and / or uplink.

[0050] In some aspects, UE 120, base station 110, a component of a base station, or another network device may include means for initiating, means for receiving, means for releasing, means for registering, means for replacing, means for storing, means for generating, and / or means for sending. Such means may include in conjunction with Figure 2 One or more components of a UE 120 or base station 110 are depicted.

[0051] As pointed out above, Figure 2 This is provided as an example only. Other examples can be found in the reference Figure 2 The examples described are different.

[0052] The deployment of a communication system (such as a 5G New Radio (NR) system) can be arranged with various components or constituent parts in a variety of ways. In a 5G NR system or network, a network node, a network entity, a mobility element of a network, a radio access network (RAN) node, a core network node, a network element or a network equipment (such as a base station (BS) or one or more units (or one or more components) performing base station functionality) can be implemented in an aggregated or decomposed architecture. For example, a BS (such as a Node B (NB), an evolved NB (eNB), an NR BS, a 5G NB, an access point (AP), a transmit and receive point (TRP) or a cell, etc.) can be implemented as an aggregated base station (also referred to as an independent BS or a monolithic BS) or a decomposed base station.

[0053] 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 decomposed base station may be configured to utilize a protocol stack that is physically or logically distributed between 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 in one or more other RAN nodes. A DU may be implemented to communicate with one or more RUs. Each of a CU, a DU, and a RU may also be implemented as a virtual unit (e.g., a virtual central unit (VCU), a virtual distributed unit (VDU), or a virtual radio unit (VRU)).

[0054] Base station type operations or network designs may take into account the aggregated nature of base station functionality. For example, a disaggregated base station may be used in an integrated access and backhaul (IAB) network, an open radio access network (O-RAN (network configurations such as those initiated by the O-RAN Alliance)), or a virtualized radio access network (vRAN, also known as a cloud radio access network (C-RAN)). Decomposition may include distributing functionality across two or more units at various physical locations, as well as virtually distributing functionality of at least one unit, which may enable flexibility in network design. Individual units of a disaggregated base station or disaggregated RAN architecture may be configured for wired or wireless communication with at least one other unit.

[0055] Figure 3 A diagram illustrating an example decomposed base station 300 architecture is shown. The decomposed base station 300 architecture may include one or more central units (CUs) 310 that may communicate directly with a core network 320 via a backhaul link, or indirectly with the core network 320 through one or more decomposed base station units, such as a near real-time (near-RT) RAN intelligent controller (RIC) 325 via an E2 link, or a non-real-time (non-RT) RIC 315 associated with a service management and orchestration (SMO) framework 305, or both. The CU 310 may communicate with one or more distributed units (DUs) 330 via respective midhaul links, such as an F1 interface. The DU 330 may communicate with one or more radio units (RUs) 340 via respective fronthaul links. The RU 340 may communicate with respective UEs 120 via one or more radio frequency (RF) access links. In some implementations, a UE 120 may be served simultaneously by multiple RUs 340.

[0056] Each of these units (e.g., CU 310, DU 330, RU 340, and near-RT RIC 325, non-RTRIC 315, and SMO framework 305) may include one or more interfaces, or may be coupled to one or more interfaces configured to receive or send signals, data, or information (collectively referred to as signals) via a wired or wireless transmission medium. Each of the units or an associated processor or controller that provides instructions to the communication interface of these units may be configured to communicate with one or more of the other units via a transmission medium. For example, these units may include a wired interface that is configured to receive or send 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, a transmitter, or a transceiver (such as a radio frequency (RF) transceiver) that is configured to receive or send signals, or both, to one or more of the other units on a wireless transmission medium.

[0057] In some aspects, the CU 310 may host one or more higher layer control functions. Such control functions may include radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (SDAP), etc. Each control function may be implemented using an interface that is configured to communicate signals with other control functions hosted by the CU 310. The CU 310 may be configured to handle user plane functionality (e.g., central unit-user plane (CU-UP)), control plane functionality (e.g., central unit-control plane (CU-CP)), or a combination thereof. In some specific implementations, the CU 310 may be logically split into one or more CU-UP units and one or more CU-CP units. When implemented in an O-RAN configuration, the CU-UP unit may communicate bidirectionally with the CU-CP unit via an interface (such as an E1 interface). As needed, the CU 310 may be implemented to communicate with the DU 330 for network control and signaling.

[0058] DU 330 may correspond to a logical unit that includes one or more base station functions for controlling the operation of one or more RU 340. In some aspects, DU 330 may host one or more of a radio link control (RLC) layer, a medium access control (MAC) layer, and one or more high physical (PHY) layers (such as modules for forward error correction (FEC) encoding and decoding, scrambling, modulation and demodulation, etc.) depending at least in part on a functional partitioning such as that defined by the Third Generation Partnership Project (3GPP). In some aspects, DU 330 may also host one or more low PHY layers. Each layer (or module) may be implemented using an interface that is configured to communicate signals with other layers (and modules) hosted by DU 330 or with control functions hosted by CU 310.

[0059] The lower layer functionality may be implemented by one or more RUs 340. In some deployments, a RU 340 controlled by a DU 330 may correspond to a logical node that hosts RF processing functions or low PHY layer functions (such as performing Fast Fourier Transform (FFT), Inverse FFT (iFFT), digital beamforming, physical random access channel (PRACH) extraction and filtering, etc.), or both, based at least in part on a functional split (such as a lower layer functional split). In such an architecture, the RU 340 may be implemented to handle over-the-air (OTA) communications with one or more UEs 120. In some implementations, real-time and non-real-time aspects of control and user plane communications with the RU 340 may be controlled by the corresponding DU 330. In some scenarios, this configuration may enable the DU 330 and the CU 310 to be implemented in a cloud-based RAN architecture (such as a vRAN architecture).

[0060] The SMO framework 305 may be configured to support RAN deployment and provisioning of non-virtualized network elements and virtualized network elements. For non-virtualized network elements, the SMO framework 305 may be configured to support the deployment of dedicated physical resources for RAN coverage requirements, which may be managed via an operation and maintenance interface (such as an O1 interface). For virtualized network elements, the SMO framework 305 may be configured to interact with a cloud computing platform (such as an open cloud (O-Cloud) platform 390) to perform network element lifecycle management (such as instantiating virtualized network elements) via a cloud computing platform interface (such as an O2 interface). Such virtualized network elements may include, but are not limited to, CU 310, DU 330, RU 340, and near-RT RIC 325. In some specific implementations, the SMO framework 305 may communicate with hardware aspects of the 4G RAN (such as an open eNB (O-eNB) 311) via the O1 interface. Additionally, in some specific implementations, the SMO framework 305 may communicate directly with one or more RUs 340 via the O1 interface. The SMO framework 305 may also include a non-RT RIC 315 configured to support the functionality of the SMO framework 305 .

[0061] The non-RT RIC 315 may be configured to include logic functions that enable non-real-time control and optimization of RAN elements and resources, artificial intelligence / machine learning (AI / ML) workflows including model training and updating, or policy-based guidance of applications / features in the near-RT RIC 325. The non-RT RIC 315 may be coupled to or communicate with the near-RT RIC 325 (such as via an A1 interface). The near-RT RIC 325 may be configured to include logic functions that enable near-real-time control and optimization of RAN elements and resources via data collection and actions on an interface (such as via an E2 interface) that connects one or more CUs 310, one or more DUs 330, or both, and the O-eNB 311 with the near-RT RIC 325.

[0062] In some implementations, in order to generate an AI / ML model to be deployed in the near-RT RIC 325, the non-RT RIC 315 may receive parameters or external enrichment information from an external server. Such information may be utilized by the near-RT RIC 325 and may be received from a non-network data source or from a network function at the SMO framework 305 or the non-RT RIC 315. In some examples, the non-RT RIC 315 or the near-RT RIC 325 may be configured to tune RAN behavior or performance. For example, the non-RT RIC 315 may monitor long-term trends and patterns of performance and employ AI / ML models to perform corrective actions through the SMO framework 305 (such as via reconfiguration of O1) or via the creation of RAN management policies (such as A1 policies).

[0063] In existing technologies for mobile communications, such as using telematics, when the Internet Protocol (IP) address assigned to the user equipment (UE) changes during handover to another network, the user equipment (UE) ends the call. This handover can be part of an evolved packet data gateway (EPDG) handover from a fifth generation (5G) new radio (NR) network to an IP multimedia subsystem (IMS) network, such as a wireless local area network (WLAN) (e.g., 802.11 WiFi), and vice versa. These handover procedures have many indoor use cases, for example, where the UE is handed over from a cellular network to a WiFi network when the cellular signal does not reach all parts of a building with good WiFi coverage. Handovers may occur when cellular network connectivity is lost, for example due to poor cell conditions in an area with strong WiFi coverage. Handover interruptions caused by IP address changes negatively affect the user experience because such handovers occur implicitly without user intervention, resulting in dropped calls due to reasons unknown to the user.

[0064] According to aspects of the present disclosure, a process is introduced for a UE that experiences network impairment to release a call connected to a remote UE. The new process then restores the call by establishing a new call to replace the dropped / released call. The new call is established using a new invite message to the remote UE. The new invite message includes replacement header information.

[0065] Aspects of the present disclosure are beneficial when a UE is registered with an NR or Long Term Evolution (LTE) network and is also connected to a WLAN access point (AP). In this example, a user makes a voice call over the NR network and the call is connected to the called party. During the call, when the call is handed over to the WLAN due to handover criteria, the network reports an IP address change event as part of the handover procedure. Since the call has been established with a different IP address and the remote UE cannot be updated with the new IP address without completing the registration procedure with the new IP address, the call will be immediately dropped.

[0066] To address these issues, aspects of the present disclosure clear the call locally. That is, the calling UE releases resources associated with the call. In some implementations, a custom reason may be provided to a user interface (UI) to notify the user that the call is in a reconnecting state due to network impairment. The calling UE also stores certain header information associated with the first call and registers a new IP address with the network. Once registration is complete, the calling UE transmits an INVITE to the remote UE to replace certain header information associated with the original call as part of a replacement header, thereby enabling the remote UE to resume the previous call.

[0067] Figure 4 is a timing diagram illustrating a handover failure due to an Internet Protocol (IP) address change. Figure 4 In the example of , the calling UE 120-1 establishes a call with the called UE 120-2 via a network entity 405 such as a base station, a component of a base station (e.g., DU, CU, RU), or a WLAN (or WiFi) access point. At time t1, the calling UE 120-1 registers with the network 405. For example, the registration may include registering with the NR network and also logging in to the WiFi access point. At time t2, the calling UE 120-1 sends an invitation message to the network 405. For example, the invitation message may be a voice based on NR. At time t3, the network 405 forwards the invitation message to the called UE 120-2. At time t4, the called UE 120-2 sends a ringing message to the network 405, which forwards the ringing message to the calling UE 120-1 at time t5. At time t6 and t7, the called UE 120-2 and the network 405 send OK messages to the calling UE 120-1, respectively, to indicate that the call is successfully established.

[0068] For some reason, at time t8, the calling UE 120-1 initiates a handover. For example, these reasons may include that the measured signal strength drops below a threshold or that the service is lost. During the handover process, at time t9, the calling UE 120-1 receives an IP address change message from a lower layer. The IP address change event may be caused by an EPDG handover from 5G to WiFi. Due to the IP address change, at time t10, the calling UE 120-1 ends the call. The network 405 forwards the end call message to the called UE 120-2 at time t11. At times t12 and t13, an OK message confirming the call termination is delivered from the called UE 120-2 to the network 405, and from the network 405 to the calling UE 120-1, respectively.

[0069] Figure 5 is a timing diagram illustrating an example of connected call resumption after an IP address change according to aspects of the present disclosure. Figure 5 In the example of , the calling UE 120-1 establishes a call with the called UE 120-2 via a network entity 405 such as a base station, a component of a base station (e.g., DU, CU, RU), or a WLAN (or WiFi) access point. At time t1, the calling UE 120-1 registers with the network 405. For example, the registration may include registering with the NR network and also logging in to the WiFi access point. At time t2, the calling UE 120-1 sends an invitation message to the network 405. For example, the invitation message may be a voice based on NR. At time t3, the network 405 forwards the invitation message to the called UE 120-2. At time t4, the called UE 120-2 sends a ringing message to the network 405, which forwards the ringing message to the calling UE 120-1 at time t5. At times t6 and t7, the called UE 120-2 and the network 405 send OK messages to the calling UE 120-1, respectively, to indicate that the call is successfully established.

[0070] At time t8, calling UE 120-1 initiates handover. During the handover, at time t9, calling UE 120-1 receives an IP address change message from a lower layer. Instead of ending the call due to the IP address change, at time t10, calling UE 120-1 stores call header information associated with the call. More specifically, calling UE 120-1 backs up information about the call (e.g., call ID header), information about the calling party (e.g., "from" header information), and information about the called party (e.g., "to" header information). Calling UE 120-1 also clears the call. That is, calling UE 120-1 refreshes registration resources. In some aspects, calling UE 120-1 generates a user interface message to notify the user that calling UE 120-1 is trying to reconnect the call.

[0071] At time t11, the calling UE 120-1 continues to register the new IP address at the network 405, for example, to the WiFi access point. Once the calling UE 120-1 registers with the new address, the calling UE 120-1 establishes a new call at times t12 and t13. More specifically, the calling UE 120-1 replaces the header information with the header information of the previous call (such as the call ID, "to" tag, and "from" tag stored locally at time t10). The calling UE 120-1 transmits an invitation message with a replaced header to establish a new call. At time t14, the called UE 120-2 transmits an OK message with new session parameters. The network 405 forwards the OK message to the calling UE 120-1 at time t15 to resume the call with the new IP address. Therefore, the previous call is replaced by the new call and is resumed.

[0072] According to various aspects of the present disclosure, calls can be smoothly resumed in the event of a network impairment event such as an IP address change due to handover, a packet data network outage due to a radio access technology (RAT) loss, etc. In these aspects, the UE resumes the call on the new network with a new IP address.

[0073] As shown above, Figures 4 to 5 Provided as an example. Other examples may be relevant to Figures 4 to 5 The examples described are different.

[0074] Figure 6 6 is a flow chart illustrating an example process 600 performed, for example, by a user equipment (UE) in accordance with various aspects of the present disclosure. Example process 600 is an example of connected call recovery during handover from one wireless network to another wireless network. The operations of process 600 may be implemented by UE 120.

[0075] At box 602, a user equipment (UE) initiates a handover of a first call from a source network to a target network. The first call is associated with a first header information. For example, the UE (e.g., using a controller / processor 280, a memory 282, etc.) can initiate a handover of the first call. In some aspects, the target network is an IP multimedia subsystem (IMS) network. The first header information can be a call identification (ID), information about a calling party, and information about a called party. In some aspects, the source network is a cellular network, and the target network is a wireless local area network (WLAN). For example, the cellular network can be a fifth generation (5G) new radio (NR) or a fourth generation (4G) long term evolution (LTE) network.

[0076] At block 604, a user equipment (UE) receives a message indicating that an Internet Protocol (IP) address is changed to a new IP address during a handover. For example, the UE (e.g., using antenna 252, DEMOD / MOD 254, MIMO detector 256, receive processor 258, controller / processor 280, memory 282, etc.) may receive the message. At block 606, the user equipment (UE) releases resources associated with the first call in response to receiving the message. For example, the UE (e.g., using controller / processor 280, memory 282, etc.) may release the resources. The UE may also locally store the first header information.

[0077] At block 608, the user equipment (UE) registers the new IP address with the target network. For example, the UE (e.g., using the controller / processor 280, the memory 282, etc.) may register the new IP address. At block 610, the user equipment (UE) initiates a second call using the first header information. For example, the UE (e.g., using the controller / processor 280, the memory 282, etc.) may initiate the second call.

[0078] At block 612, the user equipment (UE) replaces the first call with the second call and the new IP address. For example, the UE (e.g., using the controller / processor 280, the memory 282, etc.) may replace the first call. In some aspects, the UE may generate a user interface message indicating an attempt to reconnect the first call.

[0079] Figure 7 6 is a flow chart illustrating an example process 700 performed, for example, by a network device, in accordance with various aspects of the present disclosure. Example process 700 is an example of connected call recovery during handover from one wireless network to another wireless network. The operations of process 600 may be implemented by base station 110, a component of a base station, or some other network element, such as a WLAN network element.

[0080] At box 702, the base station receives a request to hand over a first call from a source network to a target network. The first call is associated with a first header information. For example, the base station (e.g., using antenna 234, MOD / DEMOD 232, MIMO detector 236, receiving processor 238, controller / processor 240, memory 242, etc.) may receive the request. The first header information may be a call identification (ID), information about a calling party, and information about a called party. In some aspects, the source network is a cellular network, and the target network is a wireless local area network (WLAN). For example, the cellular network may be a fifth generation (5G) new radio (NR) or a fourth generation (4G) long term evolution (LTE) network.

[0081] At block 704, the base station sends a message indicating that an Internet Protocol (IP) address is changed to a new IP address during the handover. For example, the base station (e.g., using antenna 234, MOD / DEMOD 232, TX MIMO processor 230, transmit processor 220, controller / processor 240, memory 242, etc.) may send the message. At block 706, the base station releases resources associated with the first call. For example, the base station (e.g., using controller / processor 240, memory 242, etc.) may release resources. At block 708, the base station registers the new IP address. For example, the base station (e.g., using transmit processor 220, controller / processor 240, memory 242, etc.) may register the new IP address.

[0082] At block 710, the base station receives signaling for initiating a second call using the first header information. For example, the base station (e.g., using antenna 234, MOD / DEMOD 232, MIMO detector 236, receive processor 238, controller / processor 240, memory 242, etc.) may receive the signaling. At block 712, the base station replaces the first call with the second call and the new IP address. For example, the base station (e.g., using controller / processor 240, memory 242, etc.) may replace the first call.

[0083] Example aspects

[0084] Aspect 1: A method of wireless communication, comprising: initiating a handover of a first call from a source network to a target network, the first call being associated with first header information; receiving a message indicating that an Internet Protocol (IP) address is changed to a new IP address during the handover; releasing resources associated with the first call in response to receiving the message; registering the new IP address with the target network; initiating a second call using the first header information; and replacing the first call with the second call and the new IP address.

[0085] Aspect 2: The method according to aspect 1, wherein the target network comprises an IP Multimedia Subsystem (IMS) network.

[0086] Aspect 3: The method according to aspect 1 or 2, wherein the first header information includes a call identification (ID), information about a calling party, and information about a called party.

[0087] Aspect 4: The method according to any one of the preceding aspects further comprises storing the first header information locally.

[0088] Aspect 5: The method according to any one of aspects 1, 3 or 4, wherein the source network comprises a cellular network, and the target network comprises a wireless local area network (WLAN).

[0089] Aspect 6: A method according to any one of the preceding aspects, wherein the cellular network comprises a fifth generation (5G) New Radio (NR) or a fourth generation (4G) Long Term Evolution (LTE) network.

[0090] Aspect 7: The method according to any one of the preceding aspects further comprises generating a user interface message indicating an attempt to reconnect the first call.

[0091] Aspect 8: A method for wireless communication by a network entity, the method comprising: receiving a request to hand over a first call from a source network to a target network, the first call being associated with first header information; sending a message indicating that an Internet Protocol (IP) address is changed to a new IP address during the handover; releasing resources associated with the first call; registering the new IP address; receiving signaling to initiate a second call using the first header information; and replacing the first call with the second call and the new IP address.

[0092] Aspect 9: The method according to aspect 8, wherein the target network comprises an IP Multimedia Subsystem (IMS) network.

[0093] Aspect 10: The method according to aspect 8 or 9, wherein the first header information includes a call identification (ID), information about a calling party, and information about a called party.

[0094] Aspect 11: The method according to any one of aspects 8 or 10, wherein the source network comprises a cellular network, and the target network comprises a wireless local area network (WLAN).

[0095] Aspect 12: The method according to any one of aspects 8 to 11, wherein the cellular network comprises a fifth generation (5G) New Radio (NR) or a fourth generation (4G) Long Term Evolution (LTE) network.

[0096] Aspect 13: A device for wireless communication, the device comprising: a memory; and at least one processor coupled to the memory, the at least one processor being configured to: initiate a handover of a first call from a source network to a target network, the first call being associated with first header information; receive a message indicating that an Internet Protocol (IP) address is changed to a new IP address during the handover; release resources associated with the first call in response to receiving the message; register the new IP address with the target network; initiate a second call using the first header information; and replace the first call using the second call and the new IP address.

[0097] Aspect 14: The apparatus according to aspect 13, wherein the target network comprises an IP Multimedia Subsystem (IMS) network.

[0098] Aspect 15: The apparatus according to aspect 13 or 14, wherein the first header information includes a call identification (ID), information about a calling party, and information about a called party.

[0099] Aspect 16: The apparatus according to any one of aspects 13 to 15, wherein the at least one processor is further configured to store the first header information locally.

[0100] Aspect 17: The apparatus according to any one of aspects 13, 15 or 16, wherein the source network comprises a cellular network and the target network comprises a wireless local area network (WLAN).

[0101] Aspect 18: An apparatus according to any one of aspects 13 to 17, wherein the cellular network comprises a fifth generation (5G) New Radio (NR) or a fourth generation (4G) Long Term Evolution (LTE) network.

[0102] Aspect 19: The apparatus according to any one of aspects 13 to 18, wherein the at least one processor is further configured to generate a user interface message indicating an attempt to reconnect the first call.

[0103] Aspect 20: An apparatus for wireless communication by a network entity, the apparatus comprising: a memory; and at least one processor coupled to the memory, the at least one processor being configured to: receive a request to hand over a first call from a source network to a target network, the first call being associated with first header information; send a message indicating that an Internet Protocol (IP) address is changed to a new IP address during the handover; release resources associated with the first call; register the new IP address; receive signaling to initiate a second call using the first header information; and replace the first call with the second call and the new IP address.

[0104] Aspect 21: The apparatus according to Aspect 20, wherein the target network comprises an IP Multimedia Subsystem (IMS) network.

[0105] Aspect 22: The apparatus according to aspect 21, wherein the first header information includes a call identification (ID), information about a calling party, and information about a called party.

[0106] Aspect 23: The apparatus according to any one of aspects 20 to 22, wherein the source network comprises a cellular network, and the target network comprises a wireless local area network (WLAN).

[0107] Aspect 24: An apparatus according to any one of aspects 20 to 23, wherein the cellular network comprises a fifth generation (5G) New Radio (NR) or a fourth generation (4G) Long Term Evolution (LTE) network.

[0108] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of these aspects.

[0109] As used, the term "component" is intended to be broadly interpreted as hardware, firmware, and / or a combination of hardware and software. As used, a processor is implemented using hardware, firmware, and / or a combination of hardware and software.

[0110] Some aspects are described in conjunction with thresholds. As used, satisfying a threshold may refer to a value being greater than a threshold, greater than or equal to a threshold, less than a threshold, less than or equal to a threshold, equal to a threshold, not equal to a threshold, etc., depending on the context.

[0111] It will be apparent that the described systems and / or methods can be implemented in various forms of hardware, firmware, and / or a combination of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods does not limit the aspects. Therefore, the operation and performance of these systems and / or methods are described without reference to specific software code, and it should be understood that software and hardware used to implement these systems and / or methods can be designed based at least in part on these descriptions.

[0112] Although the specific combination of features is set forth in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features can be combined in a manner that is not specifically set forth in the claims and / or is not disclosed in the specification. Although each dependent claim listed below may directly rely only on one claim, the disclosure of various aspects includes each dependent claim and each other claim combination in the claim set. The phrase "at least one" mentioned in the list of items refers to any combination of those items, including a single member. For example, "at least one of a, b or c" is intended to cover a, b, c, ab, ac, bc and abc, and any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc and ccc, or any other ordering of a, b and c).

[0113] The elements, actions or instructions used should not be interpreted as critical or essential unless explicitly described as such. In addition, as used, the articles "a" and "an" are intended to include one or more items, and they can be used interchangeably with "one or more". In addition, as used, the terms "set" and "group" are intended to include one or more items (e.g., related items, unrelated items, combinations of related items and unrelated items, etc.), and can be used interchangeably with "one or more". If only one item is intended to be referred to, the phrase "only one" or similar terms are used. In addition, as used, the terms "having" and the like are intended to be open terms. In addition, the phrase "based on" is intended to mean "based at least in part on", unless otherwise explicitly stated.

Claims

1. A method for wireless communication, the method comprising: Initiating a handover of a first call from a source network to a target network, the first call being associated with the first header information; receiving a message indicating that an Internet Protocol (IP) address is to be changed to a new IP address during the handover; releasing resources associated with the first call in response to receiving the message; Registering the new IP address with the target network; Initiating a second call using the first header information; as well as The first call is replaced with the second call and the new IP address.

2. The method of claim 1, wherein the target network comprises an IP Multimedia Subsystem (IMS) network.

3. The method according to claim 1, wherein the first header information includes a call identification (ID), information about a calling party, and information about a called party. The method according to claim 1 , further comprising storing the first header information locally.

5. The method of claim 1, wherein the source network comprises a cellular network and the target network comprises a wireless local area network (WLAN).

6. The method of claim 5, wherein the cellular network comprises a fifth generation (5G) New Radio (NR) or a fourth generation (4G) Long Term Evolution (LTE) network.

7. The method of claim 1, further comprising generating a user interface message indicating an attempt to reconnect the first call.

8. A method for wireless communication by a network entity, the method comprising: receiving a request to hand over a first call from a source network to a target network, the first call being associated with first header information; sending a message indicating that an Internet Protocol (IP) address is changed to a new IP address during the handover; releasing resources associated with the first call; registering the new IP address; receiving signaling for initiating a second call using the first header information; as well as The first call is replaced with the second call and the new IP address.

9. The method of claim 8, wherein the target network comprises an IP Multimedia Subsystem (IMS) network.

10. The method of claim 8, wherein the first header information includes a call identification (ID), information about a calling party, and information about a called party.

11. The method of claim 8, wherein the source network comprises a cellular network and the target network comprises a wireless local area network (WLAN).

12. The method of claim 11, wherein the cellular network comprises a fifth generation (5G) New Radio (NR) or a fourth generation (4G) Long Term Evolution (LTE) network.

13. An apparatus for wireless communication, the apparatus comprising: Memory; and at least one processor coupled to the memory, the at least one processor configured to: Initiating a handover of a first call from a source network to a target network, the first call being associated with the first header information; receiving a message indicating that an Internet Protocol (IP) address is to be changed to a new IP address during the handover; releasing resources associated with the first call in response to receiving the message; Registering the new IP address with the target network; Initiating a second call using the first header information; as well as The first call is replaced with the second call and the new IP address.

14. The apparatus of claim 13, wherein the target network comprises an IP Multimedia Subsystem (IMS) network.

15. The apparatus of claim 13, wherein the first header information includes a call identification (ID), information about a calling party, and information about a called party.

16. The apparatus of claim 13, wherein the at least one processor is further configured to locally store the first header information.

17. The apparatus of claim 13, wherein the source network comprises a cellular network and the target network comprises a wireless local area network (WLAN).

18. The apparatus of claim 17, wherein the cellular network comprises a fifth generation (5G) New Radio (NR) or a fourth generation (4G) Long Term Evolution (LTE) network.

19. The apparatus of claim 13, wherein the at least one processor is further configured to generate a user interface message indicating an attempt to reconnect the first call.

20. An apparatus for wireless communication by a network entity, the apparatus comprising: Memory; and at least one processor coupled to the memory, the at least one processor configured to: receiving a request to hand over a first call from a source network to a target network, the first call being associated with first header information; sending a message indicating that an Internet Protocol (IP) address is changed to a new IP address during the handover; releasing resources associated with the first call; registering the new IP address; receiving signaling for initiating a second call using the first header information; as well as The first call is replaced with the second call and the new IP address.

21. The apparatus of claim 20, wherein the target network comprises an IP Multimedia Subsystem (IMS) network.

22. The apparatus of claim 20, wherein the first header information includes a call identification (ID), information about a calling party, and information about a called party.

23. The apparatus of claim 20, wherein the source network comprises a cellular network and the target network comprises a wireless local area network (WLAN).

24. The apparatus of claim 23, wherein the cellular network comprises a fifth generation (5G) New Radio (NR) or a fourth generation (4G) Long Term Evolution (LTE) network.

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