Method of voice call handling and related apparatuses

Abstract

A method of voice call handling and related apparatuses are provided. The method by a user equipment (UE) includes initiating a mobile originated (MO) voice call when the UE is registered to a first RAN applied with a first RAT; performing either handover or voice call redirection from the first RAN to a second RAN applied with a second RAT, wherein an attempt of the UE at establishing a PDU session with the first RAN for IMS voice traffic for the MO voice call is rejected by a core network if the first RAN does not support IMS voice service; and establishing the PDU session with the second RAN for the IMS voice traffic for the MO voice call on the second RAT to start voice call. This method can reduce voice call setup delay.

Description

Atty. Dkt. No. 10085-01-0179-PCTMETHOD OF VOICE CALL HANDLING AND RELATED APPARATUSESCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 716,657, entitled “METHOD AND APPARATUS OF PROVIDING VOICE SERVICE IN 6G,” filed on November 5, 2024, which is hereby incorporated in its entirety by this reference.TECHNICAL FIELD

[0002] The present application relates to wireless communication technologies, and more particularly, to a method of voice call handling and related apparatuses.BACKGROUND ART

[0003] In cellular wireless communication systems developed by the Third Generation Partnership Project (3GPP), user equipment (UE) is connected by a wireless link to a radio access network (RAN). The RAN includes a set of base stations (BSs) which provide wireless links to UEs located in cells covered by the base station and an interface to a core network (CN) which provides overall network control. The RAN and CN each conduct respective functions in relation to the overall network. The so-called 4G Long Term Evolution (LTE) system, namely, an Evolved Universal Mobile Telecommunication System Territorial Radio Access Network (E-UTRAN) has been developed for a mobile access network where one or more macro-cells are supported by a base station known as an eNodeB or eNB (evolved NodeB). Evolved from LTE, the so-called 5G or new radio (NR) systems where one or more cells are supported by a base station known as a gNB. Envisioned to succeed the current 5G networks, the 6G cellular system is the forthcoming generation of wireless communication technology.

[0004] In any generation cellular networks, voice service is considered one of the most beneficial services provided to users. In 5G networks, voice services are supported in two different methods: Voice over New Radio (VoNR) and EPS (Evolved Packet System) fall back.

[0005] With VoNR, voice is delivered natively on the 5G core. It transmits both voice and data over the 5G network, ensuring a pure 5G experience. VoNR works only in 5G Standalone (SA) architecture, where the 5G Core (5GC) is deployed independently without dependency on an LTE infrastructure. The 5GC manages both voice and data, allowing seamless integration. VoNR typically uses the Enhanced Voice Services (EVS) codec, which provides better audio quality, high-definition voice, and even the capability to handle some level of background noise reduction. This is an improvement from the AMR-WB (Adaptive Multi-Rate Wideband) codec used in VoLTE.

[0006] However, when voice service is not supported with 5G standalone network, including 5GC or 5G RAN, voice traffic cannot be transmitted over 5G. In this case, EPS fallback is used to support voice for a 5G user. EPS fallback is a solution for 5G networks in which a voice call initiated in 5G reverts to LTE for completion. This fallback mechanism is important in early 5G Standalone deployments. Since LTE networks are widely established and reliable for voiceAtty. Dkt. No. 10085-01-0179-PCT services, EPS Fallback ensures uninterrupted voice quality by leveraging LTE when 5G isn’t ready to handle voice calls natively. The UE configured for EPS Fallback will be switched to LTE whenever a voice call is made. This switch is transparent to the LTE and handled by the network. EPS Fallback typically routes both the voice call and the data call over LTE. When a voice call is initiated on a 5G device in an SA network, the network checks if VoNR is supported by 5GC or 5G RAN. If VoNR is not supported, the network would initiate handover procedure to move the UE to LTE. Once in LTE, the call is managed as a standard VoLTE call, using LTE resources to maintain voice quality.

[0007] In 6G, one of deployment options is to have a 5G-6G combined common core to support both 6G RAN and 5G RAN. The UE, depending on its radio capability, may be dual connected to both 6G RAN and 5G RAN.

[0008] There is another deployment option in 6G such that the 6G core is independent to the 5G core, e.g., the 6G core is a standalone core that does not depend on the 5G core. In this case, the UE may separately register to 6G and 5G. To provide voice service to the UE, either the 6G network supports voice-over-6G or it may move the UE to 5G to make a voice call.SUMMARY

[0009] An object of the present application is to propose a method of voice call handling and related apparatuses, which can support voice service for a new RAT, reduce voice call setup delay, improve communication performance, and / or provide good reliability.

[0010] In a first aspect of the present application, provided is a method of voice call handling, performed by a user equipment (UE) in a network, including initiating a mobile originated (MO) voice call when the UE is registered to a first radio access network (RAN) applied with a first radio access technology (RAT); performing either handover or voice call redirection from the first RAN to a second RAN applied with a second RAT, wherein an attempt of the UE at establishing a protocol data unit (PDU) session with the first RAN for internet protocol (IP) multimedia subsystem (IMS) voice traffic for the MO voice call is rejected by a core network if the first RAN does not support IMS voice service; and establishing the PDU session with the second RAN for the IMS voice traffic for the MO voice call on the second RAT to start voice call.

[0011] In a second aspect of the present application, provided is a method of voice call handling, performed by a user equipment (UE) in a network, including receiving a mobile terminated (MT) voice call when the UE is registered to a first radio access network (RAN) applied with a first radio access technology (RAT); performing either handover or voice call redirection from the first RAN to a second RAN applied with a second RAT without trying to establish with a core network a protocol data unit (PDU) session with the first RAN for internet protocol (IP) multimedia subsystem (IMS) voice traffic for the MT voice call if the first RAN does not support IMS voice service; and establishing the PDU session with the second RAN for the IMS voice traffic for the MT voice call on the second RAT to start voice call.Atty. Dkt. No. 10085-01-0179-PCT

[0012] In a third aspect of the present application, provided is a user equipment (UE) in a network, including a voice call initiating module, configured to initiate a mobile originated (MO) voice call when the UE is registered to a first radio access network (RAN) applied with a first radio access technology (RAT); a handover or redirection module, configured to perform either handover or voice call redirection from the first RAN to a second RAN applied with a second RAT, wherein an attempt of the UE at establishing a protocol data unit (PDU) session with the first RAN for internet protocol (IP) multimedia subsystem (IMS) voice traffic for the MO voice call is rejected by a core network if the first RAN does not support IMS voice service; and a PDU session establishing module, configured to establish the PDU session with the second RAN for the IMS voice traffic for the MO voice call on the second RAT to start voice call.

[0013] In a fourth aspect of the present application, provided is a user equipment (UE) in a network, including a voice call receiving module, configured to receive a mobile terminated (MT) voice call when the UE is registered to a first radio access network (RAN) applied with a first radio access technology (RAT); a handover or redirection module, configured to perform either handover or voice call redirection from the first RAN to a second RAN applied with a second RAT without trying to establish with a core network a protocol data unit (PDU) session with the first RAN for internet protocol (IP) multimedia subsystem (IMS) voice traffic for the MT voice call if the first RAN does not support IMS voice service; and a PDU session establishing module, configured to establish the PDU session with the second RAN for the IMS voice traffic for the MT voice call on the second RAT to start voice call.

[0014] In a fifth aspect of the present application, provided is a user equipment (UE), including at least one memory configured to store program instructions; and at least one processor configured to execute the program instructions, which cause the at least one processor to execute the method according to the first aspect described above.

[0015] In a sixth aspect of the present application, provided is a user equipment (UE), including at least one memory configured to store program instructions; and at least one processor configured to execute the program instructions, which cause the at least one processor to execute the method according to the second aspect described above.

[0016] In a seventh aspect of the present application, a non-transitory machine-readable storage medium has stored thereon instructions that, when executed by a computer, cause the computer to perform the above method.

[0017] In an eighth aspect of the present application, a chip includes a processor, configured to call and run a computer program stored in a memory, to cause a device in which the chip is installed to execute the above method.

[0018] In a ninth aspect of the present application, a computer readable storage medium, in which a computer program is stored, causes a computer to execute the above method.

[0019] In a tenth aspect of the present application, a computer program product includes a computer program, and the computer program causes a computer to execute the above method.Atty. Dkt. No. 10085-01-0179-PCT

[0020] In an eleventh aspect of the present application, a computer program causes a computer to execute the above method.DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or related art, the following figures that will be described in the embodiments are briefly introduced. It is obvious that the drawings are merely some embodiments of the present application, a person having ordinary skill in this field can obtain other figures according to these figures without paying the premise.

[0022] FIG. l is a schematic diagram illustrating a 6G deployment option independent to the 5G core according to an embodiment of the present application.

[0023] FIG. 2 is a block diagram of a user equipment (UE) and one or more network nodes in a communication network system according to an embodiment of the present application.

[0024] FIG. 3 is a flowchart of a method of voice call handling implemented by a UE according to an embodiment of the present application.

[0025] FIG. 4 is a schematic diagram illustrating a mobile originated (MO) voice call flow according to an embodiment of the present application.

[0026] FIG. 5 is a flowchart of another method of voice call handling implemented by a UE according to an embodiment of the present application.

[0027] FIG. 6 is a schematic diagram illustrating a mobile terminated (MT) voice call flow according to an embodiment of the present application.

[0028] FIG. 7 is a block diagram of a UE starting a voice call according to an embodiment of the present application.

[0029] FIG. 8 is a block diagram of a UE receiving a voice call according to an embodiment of the present application.

[0030] FIG. 9 is a block diagram of a system for wireless communication according to an embodiment of the present application.DETAILED DESCRIPTION OF EMBODIMENTS

[0031] Embodiments of the disclosure are described in detail with the technical matters, structural features, achieved objects, and effects with reference to the accompanying drawings as follows. Specifically, the terminologies in the embodiments of the present application are merely for describing the purpose of the certain embodiment, but not to limit the disclosure.

[0032] In this document, the term “ / ” should be interpreted to indicate “and / or.” A combination 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,” or “A, B, and / or C” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any combination may contain one or more members of A, B, or C.

[0033] FIG. l is a schematic diagram illustrating a 6G deployment option independent to the 5G core according to an embodiment of the present application. Referring to FIG. 1, a user equipmentAtty. Dkt. No. 10085-01-0179-PCT(UE) with 5G and / or 6G capabilities can connect to a 5G RAN or a 6G RAN or has dual connectivity to both the 5G RAN and the 6G RAN for data transmission and / or voice communication under the control of separated 5G and 6G core networks. The 5G core network may include, but is not limited to, a 5G Access and Mobility Management Function (AMF), a 5G Session Management Function (SMF), a 5G User Plane Function (UPF), and other 5G network functions (NFs) compatible with 5G communication standards. On the other hand, the 6G core network may include, but is not limited to, a 6G Mobility Management (MM), a 6G Session Management (SM), a 6G UPF, and some other 6G NFs compatible with 6G communication standards. In general, the UPF plays a crucial role in the user plane architecture within the 5G Core (5GC) and 6G Core (6GC). Once the SMF provisions the UPF with PDRs, i.e. the rules for detecting and handling the packets, the UPF becomes responsible for managing and forwarding user plane data traffic between the radio access network (RAN) and external data networks, such as the Internet or private networks. The SMF is mainly responsible for executing session management tasks. The AMF is mainly responsible for executing access and UE mobility management tasks. The core network may further include a Policy Control Function (PCF), which manages and controls policy transmission and update of the two network elements (the AMF and the SMF). The 6G MM and the 6G SM may have functions similar to the 5G AMF and the 5G SMF respectively, but complies with 6G protocol.

[0034] FIG. 2 illustrates that, in some embodiments, a user equipment (UE) 10 and one or more network nodes 20 in a communication network system 30 according to an embodiment of the present application are provided. The communication network system 30 includes the UE 10 and one or more network nodes 20. A network node 20 may communicate with the UE 10 directly or via another network node 20. The network nodes 20 may refer to one or more types of network devices, network elements or network functions. One of these could be 5G / 6G NF, like AMF, NASRF, PCF, SMF, and etc.. Another type is a network device such as a base station (e.g., gNB). The UE 10 may include a memory 12, a transceiver 13, and a processor 11 coupled to the memory 12 and the transceiver 13. The one or more network nodes 20 may include a memory 22, a transceiver 23, and a processor 21 coupled to the memory 22 and the transceiver 23. The processor 11 or 21 may be configured to implement proposed functions, procedures and / or methods described in this description. Layers of radio interface protocol may be implemented in the processor 11 or 21. The memory 12 or 22 is operatively coupled with the processor 11 or 21 and stores a variety of information to operate the processor 11 or 21. The transceiver 13 or 23 is operatively coupled with the processor 11 or 21, and the transceiver 13 or 23 transmits and / or receives a radio signal.

[0035] The processor 11 or 21 may include application-specific integrated circuit (ASIC), other chipset, logic circuit and / or data processing device. The memory 12 or 22 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium and / or other storage device. The transceiver 13 or 23 may include baseband circuitry to processAtty. Dkt. No. 10085-01-0179-PCT radio frequency signals. When the embodiments are implemented in software, the techniques described herein can be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The modules can be stored in the memory 12 or 22 and executed by the processor 11 or 21. The memory 12 or 22 can be implemented within the processor 11 or 21 or external to the processor 11 or 21 in which case those can be communicatively coupled to the processor 11 or 21 via various means as is known in the art.

[0036] In some embodiments, the processor 11 of the UE 10 is configured to initiate a mobile originated (MO) voice call when the UE is registered to a first radio access network (RAN) applied with a first radio access technology (RAT), perform either handover or voice call redirection from the first RAN to a second RAN applied with a second RAT, wherein an attempt of the UE at establishing a protocol data unit (PDU) session with the first RAN for internet protocol (IP) multimedia subsystem (IMS) voice traffic for the MO voice call is rejected by a core network if the first RAN does not support IMS voice service, and establish the PDU session with the second RAN for the IMS voice traffic for the MO voice call on the second RAT to start voice call. This can support voice service for a new RAT, reduce voice call setup delay, improve communication performance, and / or provide good reliability.

[0037] In some embodiments, the processor 11 of the UE 10 is configured to receive a mobile terminated (MT) voice call when the UE is registered to a first radio access network (RAN) applied with a first radio access technology (RAT), perform either handover or voice call redirection from the first RAN to a second RAN applied with a second RAT without trying to establish with a core network a protocol data unit (PDU) session with the first RAN for internet protocol (IP) multimedia subsystem (IMS) voice traffic for the MT voice call if the first RAN does not support IMS voice service, and establish the PDU session with the second RAN for the IMS voice traffic for the MT voice call on the second RAT to start voice call. This can support voice service for a new RAT, reduce voice call setup delay, improve communication performance, and / or provide good reliability.

[0038] The present disclosure sets forth techniques to provide 6G voice service. The proposed solution has some similarities to 5G-to-4G EPS fallback, where when the 5G RAN does not support IMS voice traffic, it initializes a handover to 4G. The proposed solution in this design will directly let the core network to decide without first requesting IMS PDU session establishment to the RAN. This would help reduce voice call setup delay.

[0039] FIG. 3 is a flowchart of a method 100 of voice call handling implemented by a UE according to an embodiment of the present application. Referring to FIG. 3, the method 100 includes the following steps.

[0040] In Step 102, the UE initiates a mobile originated (MO) voice call when the UE is registered to a first radio access network (RAN) (e.g., 6G RAN) applied with a first radio access technology (RAT) (e.g., 6G).Atty. Dkt. No. 10085-01-0179-PCT

[0041] More specifically, the UE is registered to the first RAN by sending a registration message to a core network (e.g., 6G core network) complied with the first RAT and receiving a registration complete message from the core network complied with the first RAT to complete the registration. The MO voice call is a voice call started by the caller’s UE.

[0042] In Step 104, the UE performs either handover or voice call redirection from the first RAN to a second RAN (e.g., 5GRAN) applied with a second RAT (e.g., 5G), wherein an attempt of the UE at establishing a protocol data unit (PDU) session with the first RAN for internet protocol (IP) multimedia subsystem (IMS) voice traffic for the MO voice call is rejected by a core network (e.g., 6G core network) if the first RAN does not support IMS voice service.

[0043] In some embodiments, the UE may establish the PDU session for transferring initial IMS signalling between the UE and the network even if the first RAN does not support the IMS voice service. The attempt of the UE at establishing the PDU session with the first RAN for the IMS voice traffic for the MO voice call is carried out by the IMS signalling transmitted in the established PDU session.

[0044] In Step 106, the UE establishes the PDU session with the second RAN for the IMS voice traffic for the MO voice call on the second RAT to start voice call.

[0045] More specifically, the PDU session with the second RAN for the IMS voice traffic for the MO voice call on the second RAT is established after the UE is registered to the second RAN.

[0046] FIG. 4 is a schematic diagram illustrating a mobile originated (MO) voice call flow according to an embodiment of the present application. Referring to FIG. 4, for MO voice call, that is, the caller’s UE starts the session, the call flow is as follows:

[0047] In Step Al, the 6G RAN registers with the 6GC about its voice support capability. If the 6G RAN does not support voice service, the 6GC will directly move the UE to 5G without attempting to set up an IMS PDU for voice call traffic. It is noted that in 5G to 4G EPS fallback, 5GC may first try to establish an IMS PDU for voice traffic before sending the UE to 5G, which will delay voice call setup.

[0048] In Step A2, the UE performs 6G registration procedure.

[0049] In Step A3, the 6G core completes UE registration by sending registration complete message to the UE.

[0050] In Step A4, an IMS PDU session for IMS voice signalling is established to transfer IMS signalling between the UE and the network. Although the 6G RAN may not support IMS voice, the IMS signalling PDU may carry initial IMS signalling between the UE and the IMS server.

[0051] In Step A5, an MO voice call is initiated at the UE.

[0052] In Step A6, the UE exchanges IMS signalling with the IMS server and the 6G core trying to establish a PDU session for IMS voice traffic.

[0053] In Step A7, the 6G core understands the 6G RAN does not support IMS voice traffic and will reject the PDU session establishment.Atty. Dkt. No. 10085-01-0179-PCT

[0054] In Step A8, the 6G core sends handover request to the 6G RAN for voice service.

[0055] In Step A9, the UE performs either handover or redirection as instructed by the 6G network and moves to 5G.

[0056] In Step A10, the UE performs mobility registration procedure in 5G.

[0057] In Step Al l, the UE establishes PDU sessions for IMS signalling and IMS voice traffic on 5G and starts voice call.

[0058] In the method 100 of voice call handling of the present application, if the first RAN does not support IMS voice service, the UE will perform either handover or voice call redirection from the first RAN to the second RAN applied with the second RAT. More particularly, an attempt of the UE at establishing a PDU session with the first RAN for IMS voice traffic for the MO voice call is rejected by the core network. With the method 100, this can support voice service for a new RAT, reduce voice call setup delay, improve communication performance, and / or provide good reliability.

[0059] FIG. 5 is a flowchart of another method 200 of voice call handling implemented by a UE according to an embodiment of the present application. Referring to FIG. 5, the method 200 includes the following steps.

[0060] In Step 202, the UE receives a mobile terminated (MT) voice call when the UE is registered to a first radio access network (RAN) (e.g., 6G RAN) applied with a first radio access technology (RAT) (e.g., 6G).

[0061] More specifically, the UE is registered to the first RAN by sending a registration message to a core network (e.g., 6G core network) complied with the first RAT and receiving a registration complete message from the core network complied with the first RAT to complete the registration.

[0062] The UE may receive a paging message from the core network and perform paging response to the paging message to receive the MT voice call. In one embodiment, a voice call indicator is included in the paging message to indicate that the paging is for voice call. In another embodiment, the paging message does not include the voice call indicator.

[0063] In Step 204, the UE performs either handover or voice call redirection from the first RAN to a second RAN (e.g., 5G RAN) applied with a second RAT (e.g., 5G) without trying to establish with a core network (e.g., 6G core network) a protocol data unit (PDU) session with the first RAN for internet protocol (IP) multimedia subsystem (IMS) voice traffic for the MT voice call if the first RAN does not support IMS voice service.

[0064] In some embodiments, the UE may establish the PDU session for transferring initial IMS signalling between the UE and the network even if the first RAN does not support the IMS voice service.

[0065] In Step 206, the UE establishes the PDU session with the second RAN for the IMS voice traffic for the MT voice call on the second RAT to start voice call.

[0066] More specifically, the PDU session with the second RAN for the IMS voice traffic for the MT voice call on the second RAT is established after the UE is registered to the second RAN.Atty. Dkt. No. 10085-01-0179-PCT

[0067] FIG. 6 is a schematic diagram illustrating a mobile terminated (MT) voice call flow according to an embodiment of the present application. Referring to FIG. 6, for MT voice call, that is, the callee’s UE receives the session, the call flow is as follows:

[0068] In Step Bl, the 6G RAN registers with the 6GC about its voice support capability. If the 6G RAN does not support voice service, the 6GC will directly move the UE to 5G without attempting to set up an IMS PDU for voice call traffic. It is noted that in 5G to 4G EPS fallback, 5GC may first try to establish an IMS PDU for voice traffic before sending the UE to 5G, which will delay voice call setup.

[0069] In Step B2, the UE performs 6G registration procedure.

[0070] In Step B3, the 6G core completes UE registration by sending registration complete message to the UE.

[0071] In Step B4, an IMS PDU session for IMS voice signalling is established to transfer IMS signalling between the UE and the network. Although the 6G RAN may not support IMS voice, the IMS signalling PDU may carry initial IMS signalling between the UE and the IMS server.

[0072] In Step B5, an MT voice call is received.

[0073] In Step B6, the 6G core sends paging message to the UE. Optionally in the paging message, voice call indicator is included.

[0074] In Step B7, the UE performs paging response to the paging message.

[0075] In Step B8, since the 6G core understands the 6G RAN does not support voice call, it sends handover request to the 6G RAN without trying to establish a PDU session for IMS voice traffic.

[0076] In Step B9, the UE performs either handover or redirection as instructed by the 6G network and moves to 5G.

[0077] In Step B10, the UE performs mobility registration procedure in 5G.

[0078] In Step Bl l, the UE establishes PDU sessions for IMS signalling and IMS voice traffic on 5G and starts voice call.

[0079] In the method 200 of voice call handling of the present application, if the first RAN does not support IMS voice service, the UE will perform either handover or voice call redirection from the first RAN to the second RAN applied with the second RAT. More particularly, the system will not try to establish with the core network a PDU session with the first RAN for IMS voice traffic for the MT voice call. With the method 200, this can support voice service for a new RAT, reduce voice call setup delay, improve communication performance, and / or provide good reliability.

[0080] FIG. 7 is a block diagram of a UE 1000 starting a voice call according to an embodiment of the present application. As shown in FIG. 7, the UE 1000 includes a voice call initiating module 1001, a handover or redirection module 1002, and a PDU session establishing module 1003. The voice call initiating module 1001 is configured to initiate a mobile originated (MO) voice call when the UE is registered to a first radio access network (RAN) (e.g., 6G RAN) applied with a first radio access technology (RAT) (e.g., 6G). The handover or redirection module 1002 isAtty. Dkt. No. 10085-01-0179-PCT configured to perform either handover or voice call redirection from the first RAN to a second RAN (e.g., 5G RAN) applied with a second RAT (e.g., 5G), wherein an attempt of the UE at establishing a protocol data unit (PDU) session with the first RAN for internet protocol (IP) multimedia subsystem (IMS) voice traffic for the MO voice call is rejected by a core network if the first RAN does not support IMS voice service. The PDU session establishing module 1003 is configured to establish the PDU session with the second RAN for the IMS voice traffic for the MO voice call on the second RAT to start voice call. This can support voice service for a new RAT, reduce voice call setup delay, improve communication performance, and / or provide good reliability. Other details of the UE 1000 may be referred to the method 100 described above and are not repeated herein.

[0081] In some embodiments of the UE 1000, the UE is registered to the first RAN by sending a registration message to a core network complied with the first RAT and receiving a registration complete message from the core network complied with the first RAT to complete the registration.

[0082] In some embodiments of the UE 1000, the PDU session for transferring initial IMS signalling between the UE and the network is established even if the first RAN does not support the IMS voice service.

[0083] In some embodiments of the UE 1000, the attempt of the UE at establishing the PDU session with the first RAN for the IMS voice traffic for the MO voice call is carried out by the IMS signalling transmitted in the established PDU session.

[0084] In some embodiments of the UE 1000, the PDU session with the second RAN for the IMS voice traffic for the MO voice call on the second RAT is established after the UE is registered to the second RAN.

[0085] FIG. 8 is a block diagram of a UE 2000 receiving a voice call according to an embodiment of the present application. As shown in FIG. 8, the UE 2000 includes a voice call receiving module 2001, a handover or redirection module 2002, and a PDU session establishing module 2003. The voice call receiving module 2001 is configured to receive a mobile terminated (MT) voice call when the UE is registered to a first radio access network (RAN) (e.g., 6G RAN) applied with a first radio access technology (RAT) (e.g., 6G). The handover or redirection module 2002 is configured to perform either handover or voice call redirection from the first RAN to a second RAN (e.g., 5G RAN) applied with a second RAT (e.g., 5G) without trying to establish with a core network a protocol data unit (PDU) session with the first RAN for internet protocol (IP) multimedia subsystem (IMS) voice traffic for the MT voice call if the first RAN does not support IMS voice service. The PDU session establishing module 2003 is configured to establish the PDU session with the second RAN for the IMS voice traffic for the MT voice call on the second RAT to start voice call. This can support voice service for a new RAT, reduce voice call setup delay, improve communication performance, and / or provide good reliability. Other details of the UE 2000 may be referred to the method 200 described above and are not repeated herein. ioAtty. Dkt. No. 10085-01-0179-PCT

[0086] In some embodiments of the UE 2000, the UE is registered to the first RAN by sending a registration message to a core network complied with the first RAT and receiving a registration complete message from the core network complied with the first RAT to complete the registration.

[0087] In some embodiments of the UE 2000, the PDU session for transferring initial IMS signalling between the UE and the network is established even if the first RAN does not support the IMS voice service.

[0088] In some embodiments of the UE 2000, a paging message is received from the core network and paging response is performed in response to the paging message to receive the MT voice call.

[0089] In some embodiments of the UE 2000, the paging message is received with or without a voice call indicator.

[0090] In some embodiments of the UE 2000, the PDU session with the second RAN for the IMS voice traffic for the MT voice call on the second RAT is established after the UE is registered to the second RAN.

[0091] The embodiment of the present application further provides a computer readable storage medium for storing a computer program. The computer readable storage medium enables a computer to execute corresponding processes implemented in each of the methods of the embodiments of the present application. For brevity, details will not be described herein again.

[0092] The embodiment of the present application further provides a computer program product including computer program instructions. The computer program product enables a computer to execute corresponding processes implemented in each of the methods of the embodiments of the present application. For brevity, details will not be described herein again. \

[0093] The embodiment of the present application further provides a computer program. The computer program enables a computer to execute corresponding processes implemented in each of the methods of the embodiments of the present application. For brevity, details will not be described herein again.

[0094] The description of above device embodiments is similar to the description of above method embodiments, having beneficial effects similar to the method embodiments. For technical details not disclosed in the device embodiments of the present application, please refer to the description of the method embodiments of the present application for the purpose of understanding.

[0095] FIG. 9 is a block diagram of an example system 700 for wireless communication according to an embodiment of the present application. Embodiments described herein may be implemented into the system using any suitably configured hardware and / or software. FIG. 9 illustrates the system 700 including a radio frequency (RF) circuitry 710, a baseband circuitry 720, an application circuitry 730, a memory / storage 740, a display 750, a camera 760, a sensor 770, and an input / output (VO) interface 780, coupled with each other at least as illustrated. The application circuitry 730 may include a circuitry such as, but not limited to, one or more single-core or multicore processors. The processors may include any combination of general-purpose processors andAtty. Dkt. No. 10085-01-0179-PCT dedicated processors, such as graphics processors, application processors. The processors may be coupled with the memory / storage and configured to execute instructions stored in the memory / storage to enable various applications and / or operating systems running on the system.

[0096] The baseband circuitry 720 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processors may include a baseband processor. The baseband circuitry may handle various radio control functions that enables communication with one or more radio networks via the RF circuitry. The radio control functions may include, but are not limited to, signal modulation, encoding, decoding, radio frequency shifting, etc. In some embodiments, the baseband circuitry may provide communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry may support communication with an evolved universal terrestrial radio access network (EUTRAN) and / or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), a wireless personal area network (WPAN). Embodiments in which the baseband circuitry is configured to support radio communications of more than one wireless protocol may be referred to as multimode baseband circuitry.

[0097] In various embodiments, the baseband circuitry 720 may include circuitry to operate with signals that are not strictly considered as being in a baseband frequency. For example, in some embodiments, baseband circuitry may include circuitry to operate with signals having an intermediate frequency, which is between a baseband frequency and a radio frequency. The RF circuitry 710 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. In various embodiments, the RF circuitry 710 may include circuitry to operate with signals that are not strictly considered as being in a radio frequency. For example, in some embodiments, RF circuitry may include circuitry to operate with signals having an intermediate frequency, which is between a baseband frequency and a radio frequency.

[0098] In various embodiments, the transmitter circuitry, control circuitry, or receiver circuitry discussed above with respect to the user equipment, eNB, or gNB may be embodied in whole or in part in one or more of the RF circuitry, the baseband circuitry, and / or the application circuitry. As used herein, “circuitry” may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and / or a memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, and / or other suitable hardware components that provide the described functionality. In some embodiments, the electronic device circuitry may be implemented in, or functions associated with the circuitry may be implemented by, one or more software or firmware modules. In some embodiments, some or all of the constituent components of the baseband circuitry, the application circuitry, and / or the memory / storage may be implemented together on a system on a chip (SOC). The memory / storage 740 may be used to load and store data and / orAtty. Dkt. No. 10085-01-0179-PCT instructions, for example, for a system. The memory / storage for one embodiment may include any combination of suitable volatile memory, such as dynamic random access memory (DRAM), and / or non-volatile memory, such as flash memory.

[0099] In various embodiments, the I / O interface 780 may include one or more user interfaces designed to enable user interaction with the system and / or peripheral component interfaces designed to enable peripheral component interaction with the system. User interfaces may include, but are not limited to a physical keyboard or keypad, a touchpad, a speaker, a microphone, etc. Peripheral component interfaces may include, but are not limited to, a non-volatile memory port, a universal serial bus (USB) port, an audio jack, and a power supply interface. In various embodiments, the sensor 770 may include one or more sensing devices to determine environmental conditions and / or location information related to the system. In some embodiments, the sensors may include, but are not limited to, a gyro sensor, an accelerometer, a proximity sensor, an ambient light sensor, and a positioning unit. The positioning unit may also be part of, or interact with, the baseband circuitry and / or RF circuitry to communicate with components of a positioning network, e.g., a global positioning system (GPS) satellite.

[0100] In various embodiments, the display 750 may include a display, such as a liquid crystal display and a touch screen display. In various embodiments, the system 700 may be a mobile computing device such as, but not limited to, a laptop computing device, a tablet computing device, a netbook, an ultrabook, a smartphone, an AR / VR glasses, etc. In various embodiments, a system may have more or less components, and / or different architectures. Where appropriate, methods described herein may be implemented as a computer program. The computer program may be stored on a storage medium, such as a non-transitory storage medium.

[0101] A person having ordinary skill in the art understands that each of the units, algorithm, and steps described and disclosed in the embodiments of the present application are realized using electronic hardware or combinations of software for computers and electronic hardware. Whether the functions run in hardware or software depends on the condition of application and design requirement for a technical plan. A person having ordinary skill in the art can use different ways to realize the function for each specific application while such realizations should not go beyond the scope of the present application. It is understood by a person having ordinary skill in the art that he / she can refer to the working processes of the system, device, and unit in the above- mentioned embodiment since the working processes of the above-mentioned system, device, and unit are basically the same. For easy description and simplicity, these working processes will not be detailed.

[0102] It is understood that the disclosed system, device, and method in the embodiments of the present application can be realized with other ways. The above-mentioned embodiments are exemplary only. The division of the units is merely based on logical functions while other divisions exist in realization. It is possible that a plurality of units or components are combined or integrated in another system. It is also possible that some characteristics are omitted or skipped. On the otherAtty. Dkt. No. 10085-01-0179-PCT hand, the displayed or discussed mutual coupling, direct coupling, or communicative coupling operate through some ports, devices, or units whether indirectly or communicatively by ways of electrical, mechanical, or other kinds of forms.

[0103] The units as separating components for explanation are or are not physically separated. The units for display are or are not physical units, that is, located in one place or distributed on a plurality of network units. Some or all of the units are used according to the purposes of the embodiments. Moreover, each of the functional units in each of the embodiments can be integrated in one processing unit, physically independent, or integrated in one processing unit with two or more than two units.

[0104] If the software function unit is realized and used and sold as a product, it can be stored in a readable storage medium in a computer. Based on this understanding, the technical plan proposed by the present application can be essentially or partially realized as the form of a software product. Or, one part of the technical plan beneficial to the conventional technology can be realized as the form of a software product. The software product in the computer is stored in a storage medium, including a plurality of commands for a computational device (such as a personal computer, a server, or a network device) to run all or some of the steps disclosed by the embodiments of the present application. The storage medium includes a USB disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a floppy disk, or other kinds of media capable of storing program codes.

[0105] While the present application has been described in connection with what is considered the most practical and preferred embodiments, it is understood that the present application is not limited to the disclosed embodiments but is intended to cover various arrangements made without departing from the scope of the broadest interpretation of the appended claims.

Claims

Atty. Dkt. No. 10085-01-0179-PCTWhat is claimed is:

1. A method of voice call handling, performed by a user equipment (UE) in a network, comprising: initiating a mobile originated (MO) voice call when the UE is registered to a first radio access network (RAN) applied with a first radio access technology (RAT); performing either handover or voice call redirection from the first RAN to a second RAN applied with a second RAT, wherein an attempt of the UE at establishing a protocol data unit (PDU) session with the first RAN for internet protocol (IP) multimedia subsystem (IMS) voice traffic for the MO voice call is rejected by a core network if the first RAN does not support IMS voice service; and establishing the PDU session with the second RAN for the IMS voice traffic for the MO voice call on the second RAT to start voice call.

2. The method of claim 1, wherein the UE is registered to the first RAN by sending a registration message to a core network complied with the first RAT and receiving a registration complete message from the core network complied with the first RAT to complete the registration.

3. The method of claim 1 or 2, further comprising: establishing the PDU session for transferring initial IMS signalling between the UE and the network even if the first RAN does not support the IMS voice service.

4. The method of claim 3, wherein the attempt of the UE at establishing the PDU session with the first RAN for the IMS voice traffic for the MO voice call is carried out by the IMS signalling transmitted in the established PDU session.

5. The method any of claims 1 to 4, wherein the PDU session with the second RAN for the IMS voice traffic for the MO voice call on the second RAT is established after the UE is registered to the second RAN.

6. The method of any of claims 1 to 5, wherein the first RAT is 6G, and the first RAN is a 6G RAN.

7. The method of any of claims 1 to 6, wherein the second RAT is 5G, and the second RAN is a 5G RAN.

8. A method of voice call handling, performed by a user equipment (UE) in a network, comprising: receiving a mobile terminated (MT) voice call when the UE is registered to a first radio access network (RAN) applied with a first radio access technology (RAT); performing either handover or voice call redirection from the first RAN to a second RAN applied with a second RAT without trying to establish with a core network a protocol data unit (PDU) session with the first RAN for internet protocol (IP) multimedia subsystem (IMS) voice traffic for the MT voice call if the first RAN does not support IMS voice service; andAtty. Dkt. No. 10085-01-0179-PCT establishing the PDU session with the second RAN for the IMS voice traffic for the MT voice call on the second RAT to start voice call.

9. The method of claim 8, wherein the UE is registered to the first RAN by sending a registration message to a core network complied with the first RAT and receiving a registration complete message from the core network complied with the first RAT to complete the registration.

10. The method of claim 8 or 9, further comprising: establishing the PDU session for transferring initial IMS signalling between the UE and the network even if the first RAN does not support the IMS voice service.

11. The method of any of claims 8 to 10, further comprising: receiving a paging message from the core network and performing paging response to the paging message to receive the MT voice call.

12. The method of claim 11, wherein the paging message is received with or without a voice call indicator.

13. The method any of claims 8 to 12, wherein the PDU session with the second RAN for the IMS voice traffic for the MT voice call on the second RAT is established after the UE is registered to the second RAN.

14. The method of any of claims 8 to 13, wherein the first RAT is 6G, and the first RAN is a 6G RAN.

15. The method of any of claims 8 to 14, wherein the second RAT is 5G, and the second RAN is a 5G RAN.

16. A user equipment (UE) in a network, comprising: a voice call initiating module, configured to initiate a mobile originated (MO) voice call when the UE is registered to a first radio access network (RAN) applied with a first radio access technology (RAT); a handover or redirection module, configured to perform either handover or voice call redirection from the first RAN to a second RAN applied with a second RAT, wherein an attempt of the UE at establishing a protocol data unit (PDU) session with the first RAN for internet protocol (IP) multimedia subsystem (IMS) voice traffic for the MO voice call is rejected by a core network if the first RAN does not support IMS voice service; and a PDU session establishing module, configured to establish the PDU session with the second RAN for the IMS voice traffic for the MO voice call on the second RAT to start voice call.

17. The UE of claim 16, wherein the UE is registered to the first RAN by sending a registration message to a core network complied with the first RAT and receiving a registration complete message from the core network complied with the first RAT to complete the registration.

18. The UE of claim 16 or 17, wherein the PDU session for transferring initial IMS signalling between the UE and the network is established even if the first RAN does not support the IMS voice service.Atty. Dkt. No. 10085-01-0179-PCT19. The UE of claim 18, wherein the attempt of the UE at establishing the PDU session with the first RAN for the IMS voice traffic for the MO voice call is carried out by the IMS signalling transmitted in the established PDU session.

20. The UE any of claims 16 to 19, wherein the PDU session with the second RAN for the IMS voice traffic for the MO voice call on the second RAT is established after the UE is registered to the second RAN.

21. The UE of any of claims 16 to 20, wherein the first RAT is 6G, and the first RAN is a 6G RAN.

22. The UE of any of claims 16 to 21, wherein the second RAT is 5G, and the second RAN is a 5G RAN.

23. A user equipment (UE) in a network, comprising: a voice call receiving module, configured to receive a mobile terminated (MT) voice call when the UE is registered to a first radio access network (RAN) applied with a first radio access technology (RAT); a handover or redirection module, configured to perform either handover or voice call redirection from the first RAN to a second RAN applied with a second RAT without trying to establish with a core network a protocol data unit (PDU) session with the first RAN for internet protocol (IP) multimedia subsystem (IMS) voice traffic for the MT voice call if the first RAN does not support IMS voice service; and a PDU session establishing module, configured to establish the PDU session with the second RAN for the IMS voice traffic for the MT voice call on the second RAT to start voice call.

24. The UE of claim 23, wherein the UE is registered to the first RAN by sending a registration message to a core network complied with the first RAT and receiving a registration complete message from the core network complied with the first RAT to complete the registration.

25. The UE of claim 23 or 24, wherein the PDU session for transferring initial IMS signalling between the UE and the network is established even if the first RAN does not support the IMS voice service.

26. The UE of any of claims 23 to 25, wherein a paging message is received from the core network and paging response is performed in response to the paging message to receive the MT voice call.

27. The UE of claim 26, wherein the paging message is received with or without a voice call indicator.

28. The UE any of claims 23 to 27, wherein the PDU session with the second RAN for the IMS voice traffic for the MT voice call on the second RAT is established after the UE is registered to the second RAN.

29. The UE of any of claims 23 to 28, wherein the first RAT is 6G, and the first RAN is a 6G RAN.Atty. Dkt. No. 10085-01-0179-PCT30. The UE of any of claims 23 to 29, wherein the second RAT is 5G, and the second RAN is a 5G RAN.

31. A user equipment (UE) in a network, comprising: at least one memory configured to store program instructions; and at least one processor configured to execute the program instructions, which cause the at least one processor to execute the method of any of claims 1 to 7.

32. A user equipment (UE) in a network, comprising: at least one memory configured to store program instructions; and at least one processor configured to execute the program instructions, which cause the at least one processor to execute the method of any of claims 8 to 15.

33. A non-transitory machine-readable storage medium having stored thereon instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 7 or the method of any one of claims 8 to 15.

34. A chip, comprising: a processor, configured to call and run a computer program stored in a memory, to cause a device in which the chip is installed to execute the method of any one of claims 1 to 7 or the method of any one of claims 8 to 15.

35. A computer readable storage medium, in which a computer program is stored, wherein the computer program causes a computer to execute the method of any one of claims 1 to 7 or the method of any one of claims 8 to 15.

36. A computer program product, comprising a computer program, wherein the computer program causes a computer to execute the method of any one of claims 1 to 7 or the method of any one of claims 8 to 15.

37. A computer program, wherein the computer program causes a computer to execute the method of any one of claims 1 to 7 or the method of any one of claims 8 to 15.

Images