Emergency call seamless handover method based on 5g voice roaming

Abstract

The present application relates to the field of 5G voice roaming, and particularly relates to a seamless switching method for emergency call based on 5G voice roaming, which realizes smooth transition and reduces emergency call delay when a mobile terminal is moving in multiple regions and initiates an emergency call. The seamless switching method for emergency call based on 5G voice roaming comprises the following steps: a mobile terminal registers a VPLMN and initiates a VONR voice call; it is judged whether the VONR voice call type is an emergency call, if not, a VONR ordinary voice call is initiated on the VPLMN; if yes, it is judged whether a user identifier efs file of a current HPLMN IMS exists, if yes, efs file information is read and interacted with a core network, and an IMS voice call is initiated on the VPLMN; if not, an IMS voice call is initiated on the HPLMN. The present application is suitable for 5G voice roaming.

Description

Technical Field

[0001] This invention relates to the field of 5G voice roaming, and more specifically to a seamless emergency call handover method based on 5G voice roaming. Background Technology

[0002] Voice roaming first appeared during the GSM (Global System for Mobile Communication) era, and subsequently, data roaming was also introduced into roaming functionality as part of GPRS (General Packet Radio Service). In the 3G / 4G era, the Evolved Packet System (EPS) provided even more complex and convenient data roaming solutions on this basis.

[0003] With the evolution into the 5GS era, operators hope to develop roaming solutions based on 5GS that are compatible with EPS (Electronic Power Supply). This will enable terminals to use 5G services regardless of the operator's network or the network deployment environment.

[0004] The necessity of roaming technology: The most important purpose of roaming is to expand the service range of operators, allowing end users to use these services on other operators' networks. This network may be located in another country or across operators within the same country (this involves the concepts of international roaming and domestic roaming). Importantly, roaming can bring additional economic revenue to operators.

[0005] Therefore, with the increasing maturity of 5G technology, realizing roaming for 5GS and roaming between EPS and 5GS has become urgent. Operators will customize comprehensive roaming protocols, and this function will only need to be activated when end users need to enable or use roaming services. Roaming here does not distinguish between voice roaming and data roaming.

[0006] Figure 1 This is a simplified roaming framework for 5GS and EPS interoperability. 5GS roaming in this framework occurs between the VPLMN (Visited Public Land Mobile Network) and HPLMN (Home Public Land Mobile Network). The advantage of this framework is its compatibility with existing roaming protocols and current network deployments and 5GS. However, 5GS roaming adds network edge protection security features and a new Service-Based Architecture (SBA) to the EPS roaming framework. These new features are supported by the Secure Edge Protection Agent (SEPP).

[0007] The architecture requires terminals to support, for example, both EPS and 5GS (when a terminal connects to a VPLMN, the mobile terminal will register with the AMF (Access and Mobility Management Function), and the AMF will query the NRF (Network Repository Function)).

[0008] The mobile terminal needs to establish one or more PDU sessions. The difference between this process and the non-roaming call process is that this process involves V-NRF and H-NRF, SEEP, while V-SMF is only available when the mobile terminal is under VPLMN and the PDU session is anchored in H-SMF in HPLMMN.

[0009] Currently, provided the mobile terminal supports it, the above problems are solved through EPS Fallback. However, the EPS fallback process during roaming causes greater call latency, and unlike regular voice calls, emergency calls generally allow mobile terminals to make calls directly without inserting a SIM card. Currently, 5GS networks also provide solutions for emergency calls; for example, if the AMF (Access and Mobility Management Function) indicates support for this function, then the mobile terminal can use the emergency call service.

[0010] While roaming handover for 5GS is relatively straightforward for regular calls, emergency calls on 5GS are more complex. In emergency call fallback scenarios, the user moves from 5GS to EPS, establishes an emergency PDN (Public Data Network), and the VPLMN IMS initiates the emergency call on the EPS. However, because there's no IMS NNI interface between the VPLMN and HPLMN, the VPLMN IMS cannot obtain the mobile terminal user identifier from the HPLMN IMS. These identifiers must be acquired before the emergency call. Therefore, the emergency call process must be completed through the HPLMN IMS. This process involves multiple interactions with the core network, resulting in call delays and impacting user experience. Summary of the Invention

[0011] The purpose of this invention is to provide a seamless emergency call handover method based on 5G voice roaming, which enables a smooth transition when a mobile terminal moves across multiple regions and initiates an emergency call, thereby reducing emergency call delays.

[0012] The present invention achieves the above objective by adopting the following technical solution: a seamless emergency call handover method based on 5G voice roaming, comprising:

[0013] Step 1: Register the mobile terminal with VPLMN and initiate a VONR (Voice over New Radio) voice call;

[0014] Step 2: Determine if the VONR voice call type is an emergency call. If yes, proceed to step 4; otherwise, proceed to step 3.

[0015] Step 3: Initiate a VONR normal voice call on the VPLMN, then end;

[0016] Step 4: Read and determine if the current HPLMN IMS user identifier efs file exists. If it exists, proceed to step 5; otherwise, proceed to step 6.

[0017] Step 5: Read the EFS file information and interact with the core network, and initiate an IMS voice call on the VPLMN;

[0018] Step 6: Initiate an IMS voice call on the HPLMN.

[0019] Furthermore, the mobile terminal's VPLMN signs a roaming agreement with the HPLMN, and the agreement is configured through an efs file or an NV file.

[0020] Furthermore, the mobile terminal registers an SA or supports VONR.

[0021] Furthermore, the mobile terminal can store the user identifier of HPLMN IMS, and when an emergency call is made via VPLMN IMS, this information is read to complete the emergency call.

[0022] The beneficial effects of this invention are as follows:

[0023] When a mobile terminal enables roaming services, i.e., registers with a VPLMN, the user identifier of the mobile terminal is recorded in the EFS file according to the operator's roaming agreement. When the mobile terminal registers with the VPLMN's 5G network to make an emergency call, if the network falls back to EPS and the emergency call is initiated on IMS, the EFS file is read to obtain the mobile terminal's user identifier information. The entire process only requires retrieving the EFS file information once. Therefore, when the mobile terminal moves between multiple regions and initiates an emergency call, a smooth transition can be achieved, reducing call latency and improving user experience. Attached Figure Description

[0024] Figure 1 A schematic diagram of an existing simplified roaming framework for 5GS and EPS interoperability;

[0025] Figure 2 This is a schematic diagram of inter-system handover between VONR and VOLTE provided in an embodiment of the present invention;

[0026] Figure 3 A flowchart illustrating seamless emergency call handover based on 5G voice roaming, provided for embodiments of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] Currently, with mobile terminal support, 5GS voice roaming is mainly solved through EPS Fallback and VONR. Figure 2 This diagram illustrates the inter-system handover between VONR and VOLTE. However, the EPS fallback process during roaming can cause greater call latency. Therefore, this invention prioritizes VONR for carrying roaming services, provided the mobile terminal supports it.

[0029] This invention provides a seamless emergency call handover method based on 5G voice roaming, such as... Figure 3 As shown, it includes:

[0030] Step 1: Register the mobile terminal with VPLMN and initiate a VONR voice call;

[0031] Step 2: Determine if the VONR voice call type is an emergency call. If yes, proceed to step 4; otherwise, proceed to step 3.

[0032] Step 3: Initiate a VONR normal voice call on the VPLMN, then end;

[0033] Step 4: Read and determine if the current HPLMN IMS user identifier efs file exists. If it exists, proceed to step 5; otherwise, proceed to step 6.

[0034] Step 5: Read the EFS file information and interact with the core network, and initiate an EPS IMS or CSFB voice call on the VPLMN.

[0035] Step 6: Initiate an EPS IMS or CSFB voice call on the HPLMN.

[0036] Mobile terminals need to have the following capabilities:

[0037] 1. Currently, VPLMN needs to sign a roaming agreement with HPLMN, which can be configured through EFS or NV files (Qualcomm platform).

[0038] 2. The terminal has priority registration in SA (Standalone) or enables VONR capability;

[0039] 3. Store the user identifier of HPLMN IMS. When VPLMN IMS makes an emergency call, read this information to complete the emergency call.

[0040] Meanwhile, the mobile terminal supports roaming services and is configured with corresponding operator information; it has EPS & 5GS capabilities; and it has VONR priority capabilities.

[0041] This invention, when a mobile terminal activates roaming services (i.e., registers with a VPLMN), records the mobile terminal's user identifier in the EFS file according to the operator's roaming protocol. When the mobile terminal initiates an emergency call service on the VPLMN's 5G network, if the network falls back to EPS and an emergency call is initiated on IMS, the EFS file is read to obtain the mobile terminal's user identifier information. The entire process only requires retrieving the EFS file information once. This allows for a smooth transition when the mobile terminal moves between multiple regions and initiates an emergency call.

[0042] In summary, this invention enables a smooth transition when a mobile terminal moves across multiple regions and initiates an emergency call, reducing emergency call delays and improving user experience.

Claims

1. A seamless emergency call handover method based on 5G voice roaming, characterized in that, include: Step 1: The mobile terminal registers with the VPLMN and initiates a VONR voice call; the mobile terminal's VPLMN signs a roaming agreement with the HPLMN, and the agreement is configured through an efs file; Step 2: Determine if the VONR voice call type is an emergency call. If yes, proceed to step 4; otherwise, proceed to step 3. Step 3: Initiate a VONR normal voice call on the VPLMN, then end; Step 4: Read and determine if the current HPLMN IMS user identifier efs file exists. If it exists, proceed to step 5; otherwise, proceed to step 6. Step 5: Read the efs file information containing the user identifier of HPLMN IMS, interact with the core network, and initiate an IMS voice call on VPLMN. Step 6: Initiate an IMS voice call on the HPLMN.

2. The seamless emergency call handover method based on 5G voice roaming according to claim 1, characterized in that, The mobile terminal is registered with SA or supports VONR.

3. The seamless emergency call handover method based on 5G voice roaming according to claim 1, characterized in that, The mobile terminal can store the user identifier of HPLMN IMS, and read this information to complete the emergency call when a VPLMN IMS emergency call is made.

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