Method of voice service selection and related apparatuses

Abstract

A method of voice service selection and related apparatuses are provided. The method by a user equipment (UE) includes determining whether an internet protocol (IP) multimedia subsystem (IMS) voice service is supported on a first radio access technology (RAT) based on voice support capability of the first RAT applied on a first radio access network (RAN); and if the IMS voice service is not supported on the first RAT, sending a RAT fallback request message to fallback to a second RAT applied on a second RAN for a voice call. This method can realize voice service selection among different RATs.

Description

Atty. Dkt. No. 10085-01-0178-PCTMETHOD OF VOICE SERVICE SELECTION AND RELATED APPARATUSESCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 716,651, entitled “METHOD AND APPARATUS OF UE-TRIGGERED VOICE SERVICE SELECTION 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 service selection 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 callAtty. Dkt. No. 10085-01-0178-PCT 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 voice 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 UE 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. Support voice service in 6G would be beneficial.SUMMARY

[0008] An object of the present application is to propose a method of voice service selection and related apparatuses, which can support voice service for a new RAT, realize voice service selection among different radio access technologies (RATs), enable UE-triggered RAT selection for voice service, improve communication performance, and / or provide good reliability.

[0009] In a first aspect of the present application, provided is a method of voice service selection, performed by a user equipment (UE), including determining whether an internet protocol (IP) multimedia subsystem (IMS) voice service is supported on a first radio access technology (RAT) based on voice support capability of the first RAT applied on a first radio access network (RAN); and if the IMS voice service is not supported on the first RAT, sending a RAT fallback request message to fallback to a second RAT applied on a second RAN for a voice call.

[0010] In a second aspect of the present application, provided is a method of voice service selection, performed by a user equipment (UE), including receiving from a core network a mobile terminated (MT) voice call from internet protocol (IP) multimedia subsystem (IMS), wherein the MT voice call is intended to use a first radio access technology (RAT) applied on a first radio access network (RAN); and falling back from the first RAT to a second RAT applied on a second RAN or a third RAT applied on a third RAN to continue voice call setup for the MT voice call.

[0011] In a third aspect of the present application, provided is a user equipment (UE), including a voice service capability determination module, configured to determine whether an internet protocol (IP) multimedia subsystem (IMS) voice service is supported on a first radio access technology (RAT) based on voice support capability of the first RAT applied on a first radio access network (RAN); and a RAT fallback request module, configured to send, if the IMS voice service is not supported on the first RAT, a RAT fallback request message to fallback to a second RAT applied on a second RAN for a voice call.Atty. Dkt. No. 10085-01-0178-PCT

[0012] In a fourth aspect of the present application, provided is a user equipment (UE), including a voice call receiving module, configured to receive from a core network a mobile terminated (MT) voice call from internet protocol (IP) multimedia subsystem (IMS), wherein the MT voice call is intended to use a first radio access technology (RAT) applied on a first radio access network (RAN); and a RAT fallback module, configured to fallback from the first RAT to a second RAT applied on a second RAN or a third RAT applied on a third RAN to continue voice call setup for the MT voice call.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] In an eleventh aspect of the present application, a computer program causes a computer to execute the above method.DESCRIPTION OF DRAWINGS

[0001] 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.

[0002] FIG. 1 is a schematic diagram illustrating a 6G deployment option of combined 5G and 6G core according to an embodiment of the present application.

[0003] 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.Atty. Dkt. No. 10085-01-0178-PCT

[0004] FIG. 3 is a flowchart of a method of voice service selection implemented by a UE according to an embodiment of the present application.

[0005] FIG. 4 is a schematic diagram illustrating a mobile originated (MO) voice call flow according to an embodiment of the present application.

[0006] FIG. 5 is a flowchart of another method of voice service selection implemented by a UE according to an embodiment of the present application.

[0007] FIG. 6 is a schematic diagram illustrating a mobile terminated (MT) voice call flow according to an embodiment of the present application.

[0008] FIG. 7 is a block diagram of a UE starting a voice call according to an embodiment of the present application.

[0009] FIG. 8 is a block diagram of a UE receiving a voice call according to an embodiment of the present application.

[0010] FIG. 9 is a block diagram of a system for wireless communication according to an embodiment of the present application.DETAILED DESCRIPTION OF EMBODIMENTS

[0011] 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.

[0012] 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.

[0013] FIG. 1 is a schematic diagram illustrating a 6G deployment option of combined 5G and 6G core according to an embodiment of the present application. Referring to FIG. 1, a user equipment (UE) with 5G and / or 6G capabilities can connect to a 5G RAN and / or a 6G RAN for data transmission and / or voice communication under the control of a combined 5G and 6G core network. The core network may include an Access and Mobility Management Function (AMF), a Session Management Function (SMF), a User Plane Function (UPF) and other network functions (NFs), which are compatible with 5G and / or 6G communication standards, and some new 6GNFs if available. The UPF plays a crucial role in the user plane architecture within the 5G Core (5GC) and / or 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.Atty. Dkt. No. 10085-01-0178-PCTThe 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).

[0014] 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.

[0015] 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 process 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.

[0016] In some embodiments, the processor 11 of the UE 10 is configured to determine whether an internet protocol (IP) multimedia subsystem (IMS) voice service is supported on a first radio access technology (RAT) based on voice support capability of the first RAT applied on a first radio access network (RAN), and send, if the IMS voice service is not supported on the first RAT, a RAT fallback request message to fallback to a second RAT applied on a second RAN for a voice call. This can support voice service for a new RAT, realize voice service selection among different RATs, enable UE-triggered RAT selection for voice service, improve communication performance, and / or provide good reliability.

[0017] In some embodiments, the processor 11 of the UE 10 is configured to receive from a core network a mobile terminated (MT) voice call from internet protocol (IP) multimedia subsystemAtty. Dkt. No. 10085-01-0178-PCT(IMS), wherein the MT voice call is intended to use a first radio access technology (RAT) applied on a first radio access network (RAN), and fallback from the first RAT to a second RAT applied on a second RAN or a third RAT applied on a third RAN to continue voice call setup for the MT voice call. This can support voice service for a new RAT, realize voice service selection among different RATs, enable UE-triggered RAT selection for voice service, improve communication performance, and / or provide good reliability.

[0018] The present application proposes a UE-triggered radio access technology (RAT) selection for voice service. To allow the UE to make a selection for voice service, the network capability is determined. When a voice-centric UE performs registration procedure to the network, the network may inform the UE about network capability of voice service support. This includes:

[0019] Whether the voice service is supported by the combined 5G-6G core. This may be included in registration complete message.

[0020] Whether the voice service is supported by the 5G RAN. This may be included in registration complete message.

[0021] Whether the voice service is supported by the 6G RAN. This may be included in registration compete message or in the system information block (SIB) message by transmitted by 6G RAN.

[0022] FIG. 3 is a flowchart of a method 100 of voice service selection implemented by a UE according to an embodiment of the present application. Referring to FIG. 3, the method 100 includes the following steps.

[0023] In Step 102, the UE determines whether an internet protocol (IP) multimedia subsystem (IMS) voice service is supported on a first radio access technology (RAT) (e.g., 6G) based on voice support capability of the first RAT applied on a first radio access network (RAN) (e.g., 6G RAN).

[0024] In some embodiments, the voice support capability of the first RAT may be received from a core network and included in a registration complete message. In some other embodiments, the voice support capability of the first RAT is received from the first RAN and included in a system information message broadcast by the first RAN.

[0025] In Step 104, if the IMS voice service is not supported on the first RAT, the UE sends a RAT fallback request message to fallback to a second RAT (e.g., 5G) applied on a second RAN (e.g., 5G RAN) for a voice call.

[0026] In case that the IMS voice service is not supported on the first RAT, during a fallback procedure from the first RAT to the second RAT for the voice call, the UE may receive a handover (HO) command from the first RAN to trigger a handover from the first RAT to the second RAT and send a HO complete message to the second RAN to complete the handover.

[0027] In some embodiments, the UE may fallback to a third RAT (e.g., 4G) applied on a third RAN (e.g., 4G RAN) to continue the voice call upon a trigger from the second RAN.Atty. Dkt. No. 10085-01-0178-PCT

[0028] In some embodiments, the RAT fallback request message may be only for an IMS voice call. In case that the IMS voice service is not supported on the first RAT, the UE may remain a data call on the first RAT if the UE is capable of dual connectivity to both the first RAN and the second RAN.

[0029] 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:

[0030] In Step Al, the UE performs registration to the combined 5G-6G core network.

[0031] In Step A2, the network sends registration complete message to the UE including voice service capability support indication: o Core network voice support: Yes or No o 5G RAN voice support: Yes or No o Optionally, 6G RAN voice support: Yes or No

[0032] If core network does not support voice service, the UE performs deregistration procedure and finds another network for voice support.

[0033] In Step A3, the UE now is camped on the 6G network.

[0034] In Step A4, if the core network does not indicate 6G RAN voice support in Step A2, the UE reads System Information message of the 6G RAN to acquire 6G RAN’s capability of voice support. o This requires the 6G RAN to broadcast its voice support capability in System Information message.

[0035] In Step A5, an MO voice call is initiated on the UE. o If the UE determines voice service is supported on 6G, the UE initiates IP Multimedia Subsystem (IMS) voice call setup procedure normally.

[0036] In Step A6, if the UE determines voice service is not supported on 6G, the UE sends RAT fallback request message to the core network, likely the 6G AMF, indicating the UE may fallback to 5G for voice call. o Optionally if the UE is capable of dual radio on both the 5G RAN and the 6G RAN, the UE may indicate fallback request only for IMS Packet Data Unit (PDU). In this case, UE’ s normal data call will remain on 6G.

[0037] In Step A7, the core network sends 6G to 5G handover (HO) request to the 6G RAN indicating a voice call handover.

[0038] In Step A8, the 6G RAN configures 5G measurement to the UE and the UE reports 5G measurement results.

[0039] In Step A9, the 5G RAN, the 6G RAN, and the core network prepare HO, optionally only for IMS session.

[0040] In Step A10, the 6G RAN sends HO command to the UE to trigger 6G to 5G handover.

[0041] In Step Al l, the UE sends HO complete message to 5G RAN to complete HO.Atty. Dkt. No. 10085-01-0178-PCT

[0042] In Step A12, the UE starts voice call setup procedure on 5G. o Optionally, the 5G network may trigger EPS fallback to move the UE to 4G to continue voice call. In this case, if the data call is still on 6G network, it will be dropped and will be re-connected when the UE moves to 4G.

[0043] In Step A13, voice call traffic now is carried on the 5G network. o Optionally, the data call remains on the 6G network.

[0044] In the method 100 of voice service selection of the present application, the UE determines whether an IMS voice service is supported on a first RAT based on voice support capability of the first RAN, and if the IMS voice service is not supported on the first RAT, the UE sends a RAT fallback request message to fallback to a second RAT applied on a second RAN for a voice call. With the method 100, this can support voice service for a new RAT, realize voice service selection among different RATs, enable UE-triggered RAT selection for voice service, improve communication performance, and / or provide good reliability.

[0045] FIG. 5 is a flowchart of another method 200 of voice service selection implemented by a UE according to an embodiment of the present application. Referring to FIG. 5, the method 200 includes the following steps.

[0046] In Step 202, the UE receives from a core network a mobile terminated (MT) voice call from internet protocol (IP) multimedia subsystem (IMS), wherein the MT voice call is intended to use a first radio access technology (RAT) (e.g., 6G) applied on a first radio access network (RAN) (e.g., 6G RAN).

[0047] In Step 204, the UE fallback from the first RAT to a second RAT (e.g., 5G) applied on a second RAN (e.g., 5G RAN) or a third RAT (e.g., 4G) applied on a third RAN (e.g., 4G RAN) to continue voice call setup for the MT voice call.

[0048] In some embodiments, in case that the core network is aware of capability of voice service support of the first RAN, the voice call setup for the MT voice call may be performed according to the second RAT upon receiving an instruction from the core network to fallback from the first RAT to the second RAT (for example, from 6G to 5G) for the MT voice call if the first RAN does not support IMS voice service. In some other embodiments, the voice call setup for the MT voice call may be performed according to the third RAT upon receiving an instruction from the core network to fallback from the first RAT to the third RAT (for example, from 6G to 4G) for the MT voice call if the first RAN and the second RAN do not support IMS voice service.

[0049] In some embodiments, in case that the core network is not aware of capability of voice service support of the first RAN, the UE may receive a paging message including a voice call indicator for the MT voice call from the core network, perform paging response, and if the first RAT does not support IMS voice service, send a RAT fallback request message to the core network to fallback from the first RAT to the second RAT or the third RAT for the MT voice call.

[0050] In some embodiments, in case that the core network is not aware of capability of voice service support of the first RAN, the UE may receive from the core network a paging message thatAtty. Dkt. No. 10085-01-0178-PCT does not include a voice call indicator, performing paging response, and fallback to the second RAT or the third RAT for the MT voice call upon a fallback procedure triggered by the core network, wherein the fallback procedure is triggered when the first RAN does not support IMS voice service and a request for the voice call setup on the first RAT from the core network is rejected by the first RAN.

[0051] 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:

[0052] In Step Bl, the UE performs registration to the combined 5G-6G core network.

[0053] In Step B2, the network sends registration complete message to the UE including voice service capability support indication: o Core network voice support: Yes or No o 5G RAN voice support: Yes or No o Optionally, 6G RAN voice support: Yes or No

[0054] If core network does not support voice service, the UE performs deregistration procedure and finds another network for voice support.

[0055] In Step B3, the UE now is camped on the 6G network.

[0056] In Step B4, if the core network does not indicate 6G RAN voice support in Step B2, the UE reads System Information message of the 6G RAN to acquire 6G RAN’s capability of voice support. o This requires the 6G RAN to broadcast its voice support capability in System Information message.

[0057] There may be three different designs for a MT voice call.

[0058] Case 1 :

[0059] In Step B5, a MT voice call is received from IMS and the core network

[0060] In Step B6, if the core network is aware of 6G RAN’s capability of voice service support, the core network may directly trigger a 6G to 5G fallback to continue the voice call setup. If the core network is aware of 5G RAN’s capability of voice service support, the core network may trigger a 6G to 4G handover to move the UE to 4G for VoLTE call. o For 6G to 5G fallback, follow Step A7 to Step A13 in the call flow of MO call. o For 6G to 4G handover.

[0061] Case 2:

[0062] In Step B5, a MT voice call is received from IMS and the core network.

[0063] In Step B6, if the core network is not aware of 6G RAN’s capability of voice service support, the core network sends paging message to the UE and includes voice call indicator in the paging message.Atty. Dkt. No. 10085-01-0178-PCT

[0064] In Step B7, when the UE receives the MT voice call paging message, it performs paging response and sends RAT fallback request to the core network, same as Step A6 to Step Al 3 in the call flow of MO call.

[0065] Case 3:

[0066] In Step B5, a MT voice call is received from IMS and the core network

[0067] In Step B6, if the core network is not aware of 6G RAN’s capability of voice service support, the core network sends paging message to the UE and does not include voice call indicator in the paging message.

[0068] In Step B7, when the UE receives the paging message, it is not aware this is for a MT voice call. The UE performs normal paging response to the core network. The core network continues voice call setup. Since the 6G RAN does not support voice service, when the 6G receives voice call setup request from the core network, it will reject the request. The core network will trigger a 6G to 5G fallback procedure to move the UE to the 5G network. This is similar to the design of EPS fallback.

[0069] In the method 200 of voice service selection of the present application, the UE receives from a core network a MT voice call from IMS, in which the MT voice call is intended to use a first RAT applied on a first RAN, and fallback from the first RAT to a second RAT applied on a second RAN or a third RAT applied on a third RAN to continue voice call setup for the MT voice call. With the method 200, this can support voice service for a new RAT, realize voice service selection among different RATs, enable UE-triggered RAT selection for voice service, improve communication performance, and / or provide good reliability.

[0070] 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 service capability determination module 1001 and a RAT fallback request module 1002. The voice service capability determination module 1001 is configured to determine whether an internet protocol (IP) multimedia subsystem (IMS) voice service is supported on a first radio access technology (RAT) (e.g., 6G) based on voice support capability of the first RAT applied on a first radio access network (RAN) (e.g., 6G RAN). The RAT fallback request module 1002 is configured to send, if the IMS voice service is not supported on the first RAT, a RAT fallback request message to fallback to a second RAT (e.g., 5G) applied on a second RAN (e.g., 5G RAN) for a voice call. This can support voice service for a new RAT, realize voice service selection among different RATs, enable UE- triggered RAT selection for voice service, 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.

[0071] In some embodiments of the UE 1000, the voice support capability of the first RAT is received from a core network and included in a registration complete message.Atty. Dkt. No. 10085-01-0178-PCT

[0072] In some embodiments of the UE 1000, the voice support capability of the first RAT is received from the first RAN and included in a system information message broadcast by the first RAN.

[0073] In some embodiments of the UE 1000, the RAT fallback request message is only for an IMS voice call.

[0074] In some embodiments of the UE 1000, in case that the IMS voice service is not supported on the first RAT, a data call remains on the first RAT if the UE is capable of dual connectivity to both the first RAN and the second RAN.

[0075] In some embodiments of the UE 1000, in case that the IMS voice service is not supported on the first RAT, a handover (HO) command is received from the first RAN to trigger a handover from the first RAT to the second RAT, and a HO complete message is sent to the second RAN to complete the handover.

[0076] In some embodiments of the UE 1000, the UE fallback to a third RAT applied on a third RAN to continue the voice call upon a trigger from the second RAN.

[0077] 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 and a RAT fallback module 2002. The voice call receiving module 2001 is configured to receive from a core network a mobile terminated (MT) voice call from internet protocol (IP) multimedia subsystem (IMS), wherein the MT voice call is intended to use a first radio access technology (RAT) (e.g., 6G) applied on a first radio access network (RAN) (e.g., 6G RAN). The RAT fallback module 2002 is configured to fallback from the first RAT to a second RAT (e.g., 5G) applied on a second RAN (e.g., 5G RAN) or a third RAT (e.g., 4G) applied on a third RAN (e.g., 4G RAN) to continue voice call setup for the MT voice call. This can support voice service for a new RAT, realize voice service selection among different RATs, enable UE-triggered RAT selection for voice service, 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.

[0078] In some embodiments of the UE 2000, in case that the core network is aware of capability of voice service support of the first RAN, the voice call setup for the MT voice call is performed according to the second RAT upon receiving an instruction from the core network to fallback from the first RAT to the second RAT for the MT voice call if the first RAN does not support IMS voice service.

[0079] In some embodiments of the UE 2000, in case that the core network is aware of capability of voice service support of the first RAN and the second RAN, the voice call setup for the MT voice call is performed according to the third RAT upon receiving an instruction from the core network to fallback from the first RAT to the third RAT for the MT voice call if the first RAN and the second RAN do not support IMS voice service.Atty. Dkt. No. 10085-01-0178-PCT

[0080] In some embodiments of the UE 2000, in case that the core network is not aware of capability of voice service support of the first RAN, the UE receives a paging message including a voice call indicator for the MT voice call from the core network, performs paging response, and if the first RAT does not support IMS voice service, sends a RAT fallback request message to the core network to fallback from the first RAT to the second RAT or the third RAT for the MT voice call.

[0081] In some embodiments of the UE 2000, in case that the core network is not aware of capability of voice service support of the first RAN, the UE receives from the core network a paging message that does not include a voice call indicator, performs paging response, and fallback to the second RAT or the third RAT for the MT voice call upon a fallback procedure triggered by the core network, and wherein the fallback procedure is triggered when the first RAN does not support IMS voice service and a request for the voice call setup on the first RAT from the core network is rejected by the first RAN.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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 (I / O) 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 and dedicated processors, such as graphics processors, application processors. The processors may beAtty. Dkt. No. 10085-01-0178-PCT 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.

[0087] 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.

[0088] 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.

[0089] 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 / or instructions, for example, for a system. The memory / storage for one embodiment may include anyAtty. Dkt. No. 10085-01-0178-PCT combination of suitable volatile memory, such as dynamic random access memory (DRAM), and / or non-volatile memory, such as flash memory.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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 other hand, the displayed or discussed mutual coupling, direct coupling, or communicative couplingAtty. Dkt. No. 10085-01-0178-PCT operate through some ports, devices, or units whether indirectly or communicatively by ways of electrical, mechanical, or other kinds of forms.

[0094] 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.

[0095] 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.

[0096] 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. 10085-01-0178-PCTWhat is claimed is:

1. A method of voice service selection, performed by a user equipment (UE), comprising: determining whether an internet protocol (IP) multimedia subsystem (IMS) voice service is supported on a first radio access technology (RAT) based on voice support capability of the first RAT applied on a first radio access network (RAN); and if the IMS voice service is not supported on the first RAT, sending a RAT fallback request message to fallback to a second RAT applied on a second RAN for a voice call.

2. The method of claim 1, wherein the voice support capability of the first RAT is received from a core network and included in a registration complete message.

3. The method of claim 1, wherein the voice support capability of the first RAT is received from the first RAN and included in a system information message broadcast by the first RAN.

4. The method of any of claims 1 to 3, wherein the RAT fallback request message is only for an IMS voice call.

5. The method of any of claims 1 to 4, wherein in case that the IMS voice service is not supported on the first RAT, the method further comprising: remaining a data call on the first RAT if the UE is capable of dual connectivity to both the first RAN and the second RAN.

6. The method of any of claims 1 to 5, wherein in case that the IMS voice service is not supported on the first RAT, the method further comprising: receiving a handover (HO) command from the first RAN to trigger a handover from the first RAT to the second RAT; and sending a HO complete message to the second RAN to complete the handover.

7. The method of any of claims 1 to 6, further comprising: falling back to a third RAT applied on a third RAN to continue the voice call upon a trigger from the second RAN.

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

9. The method of any of claims 1 to 8, wherein the second RAT is 5G, and the second RAN is a 5G RAN.

10. The method of any of claims 7 to 9, wherein the third RAT is 4G, and the third RAN is a 4G RAN.

11. A method of voice service selection, performed by a user equipment (UE), comprising: receiving from a core network a mobile terminated (MT) voice call from internet protocol (IP) multimedia subsystem (IMS), wherein the MT voice call is intended to use a first radio access technology (RAT) applied on a first radio access network (RAN); andAtty. Dkt. No. 10085-01-0178-PCT falling back from the first RAT to a second RAT applied on a second RAN or a third RAT applied on a third RAN to continue voice call setup for the MT voice call.

12. The method of claim 11, wherein in case that the core network is aware of capability of voice service support of the first RAN, the voice call setup for the MT voice call is performed according to the second RAT upon receiving an instruction from the core network to fallback from the first RAT to the second RAT for the MT voice call if the first RAN does not support IMS voice service.

13. The method of claim 11, wherein in case that the core network is aware of capability of voice service support of the first RAN and the second RAN, the voice call setup for the MT voice call is performed according to the third RAT upon receiving an instruction from the core network to fallback from the first RAT to the third RAT for the MT voice call if the first RAN and the second RAN do not support IMS voice service.

14. The method of claim 11, wherein in case that the core network is not aware of capability of voice service support of the first RAN, the method further comprises: receiving a paging message including a voice call indicator for the MT voice call from the core network; and performing paging response, and if the first RAT does not support IMS voice service, sending a RAT fallback request message to the core network to fallback from the first RAT to the second RAT or the third RAT for the MT voice call.

15. The method of claim 11, wherein in case that the core network is not aware of capability of voice service support of the first RAN, the method further comprises: receiving from the core network a paging message that does not include a voice call indicator; performing paging response, and falling back to the second RAT or the third RAT for the MT voice call upon a fallback procedure triggered by the core network, wherein the fallback procedure is triggered when the first RAN does not support IMS voice service and a request for the voice call setup on the first RAT from the core network is rejected by the first RAN.

16. The method of any of claims 11 to 15, wherein the first RAT is 6G, and the first RAN is a 6G RAN.

17. The method of any of claims 11 to 16, wherein the second RAT is 5G, and the second RAN is a 5G RAN.

18. The method of any of claims 11 to 17, wherein the third RAT is 4G, and the third RAN is a 4G RAN.

19. A user equipment (UE), comprising: a voice service capability determination module, configured to determine whether an internet protocol (IP) multimedia subsystem (IMS) voice service is supported on a first radio access technology (RAT) based on voice support capability of the first RAT applied on a first radio access network (RAN); andAtty. Dkt. No. 10085-01-0178-PCT a RAT fallback request module, configured to send, if the IMS voice service is not supported on the first RAT, a RAT fallback request message to fallback to a second RAT applied on a second RAN for a voice call.

20. The UE of claim 19, wherein the voice support capability of the first RAT is received from a core network and included in a registration complete message.

21. The UE of claim 19, wherein the voice support capability of the first RAT is received from the first RAN and included in a system information message broadcast by the first RAN.

22. The UE of any of claims 19 to 21, wherein the RAT fallback request message is only for an IMS voice call.

23. The UE of any of claims 19 to 22, wherein in case that the IMS voice service is not supported on the first RAT, a data call remains on the first RAT if the UE is capable of dual connectivity to both the first RAN and the second RAN.

24. The UE of any of claims 19 to 23, wherein in case that the IMS voice service is not supported on the first RAT, a handover (HO) command is received from the first RAN to trigger a handover from the first RAT to the second RAT, and a HO complete message is sent to the second RAN to complete the handover.

25. The UE of any of claims 19 to 24, wherein the UE fallback to a third RAT applied on a third RAN to continue the voice call upon a trigger from the second RAN.

26. The UE of any of claims 19 to 25, wherein the first RAT is 6G, and the first RAN is a 6G RAN.

27. The UE of any of claims 19 to 26, wherein the second RAT is 5G, and the second RAN is a 5G RAN.

28. The UE of any of claims 25 to 27, wherein the third RAT is 4G, and the third RAN is a 4G RAN.

29. A user equipment (UE), comprising: a voice call receiving module, configured to receive from a core network a mobile terminated (MT) voice call from internet protocol (IP) multimedia subsystem (IMS), wherein the MT voice call is intended to use a first radio access technology (RAT) applied on a first radio access network (RAN); and a RAT fallback module, configured to fallback from the first RAT to a second RAT applied on a second RAN or a third RAT applied on a third RAN to continue voice call setup for the MT voice call.

30. The UE of claim 29, wherein in case that the core network is aware of capability of voice service support of the first RAN, the voice call setup for the MT voice call is performed according to the second RAT upon receiving an instruction from the core network to fallback from the first RAT to the second RAT for the MT voice call if the first RAN does not support IMS voice service.Atty. Dkt. No. 10085-01-0178-PCT31. The UE of claim 29, wherein in case that the core network is aware of capability of voice service support of the first RAN and the second RAN, the voice call setup for the MT voice call is performed according to the third RAT upon receiving an instruction from the core network to fallback from the first RAT to the third RAT for the MT voice call if the first RAN and the second RAN do not support IMS voice service.

32. The UE of claim 29, wherein in case that the core network is not aware of capability of voice service support of the first RAN, the UE receives a paging message including a voice call indicator for the MT voice call from the core network, performs paging response, and if the first RAT does not support IMS voice service, sends a RAT fallback request message to the core network to fallback from the first RAT to the second RAT or the third RAT for the MT voice call.

33. The UE of claim 29, wherein in case that the core network is not aware of capability of voice service support of the first RAN, the UE receives from the core network a paging message that does not include a voice call indicator, performs paging response, and fallback to the second RAT or the third RAT for the MT voice call upon a fallback procedure triggered by the core network, and wherein the fallback procedure is triggered when the first RAN does not support IMS voice service and a request for the voice call setup on the first RAT from the core network is rejected by the first RAN.

34. The UE of any of claims 29 to 33, wherein the first RAT is 6G, and the first RAN is a 6G RAN.

35. The UE of any of claims 29 to 34, wherein the second RAT is 5G, and the second RAN is a 5G RAN.

36. The UE of any of claims 29 to 35, wherein the third RAT is 4G, and the third RAN is a 4G RAN.

37. A user equipment (UE), 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 10.

38. A user equipment (UE), 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 18.

39. 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 10 or the method of any one of claims 11 to 18.

40. A chip, comprising:Atty. Dkt. No. 10085-01-0178-PCT 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 10 or the method of any one of claims 11 to 18.

41. 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 claims1 to 10 or the method of any one of claims 11 to 18.

42. 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 10 or the method of any one of claims 11 to 18.

43. A computer program, wherein the computer program causes a computer to execute the method of any one of claims 1 to 10 or the method of any one of claims 11 to 18.

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