System and method for combining multi-IMSI data-only SIM with voice-over-IP platform for seamless global connectivity

Abstract

A system and method for providing seamless global mobile connectivity by integrating a multi-IMSI data-only SIM with a VoIP -based communication platform. The system includes a multi-IMSI data-only SIM that dynamically switches among a plurality of IMSI profiles to provide cost-optimized data connectivity across multiple geographic regions, a VoIP application that provides one or more persistent phone numbers independent of the active IMSI profile and handles all voice calls and messaging over the data connection, and a backend synchronization system that coordinates IMSI switching with VoIP service provisioning and call routing to maintain uninterrupted communication. The system enables a user to maintain multiple simultaneously active phone numbers from different countries on a single SIM and application, receive calls on any number regardless of location, and select which number is used for outgoing communications. Synchronized provisioning ensures data and VoIP services are activated together in response to user plan purchases.

Description

SYSTEM AND METHOD FOR COMBINING MULTI-IMSI DATA-ONLY SIM WITH VOICE-OVER-IP PLATFORM FOR SEAMLESS GLOBAL CONNECTIVITYCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No.63 / 759,789, filed on February 18, 2025, the entire disclosure of which is hereby incorporated by reference in its entirety.FIELD OF THE INVENTION

[0002] This invention relates generally to telecommunications, and more specifically to a system and method for providing global mobile connectivity through the integration of a multi- IMSI (International Mobile Subscriber Identity) data-only SIM card or eSIM (embedded SIM) with a VoIP -based (Voice over Internet Protocol) calling, messaging, and number management platform, wherein the VoIP platform provides persistent phone number(s) and voice / messaging services decoupled from the underlying SIM identity, enabling seamless communication as the SIM dynamically switches between carrier identities across geographic regionsBACKGROUND OF THE INVENTION

[0003] International mobile communication has historically been constrained by the architecture of the Public Switched Telephone Network (PSTN) and the mobile network infrastructure that supports it. Conventional SIM cards and eSIM profiles are provisioned with a single IMSI that binds a subscriber to a single mobile network operator (MNO). When a subscriber travels internationally, the subscriber’s device connects to foreign networks through roaming agreements between the home MNO and visited MNOs. These roaming agreementsInventor: Simon Tian - 1 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivitytypically impose substantial surcharges on voice, SMS, and data usage, resulting in high costs for international travelers and extended-stay users.

[0004] Multi-IMSI SIM technology has emerged as a partial solution to the cost problem. A multi-IMSI SIM stores multiple IMSI profiles on a single physical SIM card or eSIM, each corresponding to a different MNO in a different country or region. By dynamically switching to a local IMSI when the subscriber enters a new region, the device can connect as a local subscriber rather than a roaming subscriber, thereby accessing local data rates and avoiding roaming surcharges.

[0005] However, multi-IMSI technology alone does not solve the complete connectivity problem for voice and messaging. When a multi-IMSI SIM switches from one IMSI to another, the subscriber’s phone number, which is tied to the IMSI and the associated MNO, changes. This means that a subscriber who receives a phone call or SMS on a phone number associated with IMSI #1 would lose access to that phone number when the SIM switches to IMSI #2. The subscriber would effectively have a different phone number in each region, creating confusion. No known provider has implemented multi-IMSI switching with traditional voice and SMS services precisely because of this phone number instability problem.

[0006] Voice over Internet Protocol (VoIP) technology enables voice calling and messaging over IP data connections rather than over circuit-switched voice channels. VoIP applications such as Skype, WhatsApp, and Google Voice are widely used for internet-based communication. VoIP phone numbers (also known as virtual numbers or DID numbers) are not tied to any particular SIM card or IMSI; they are provisioned and managed by VoIP service providers and can be accessed from any device with an internet connection.Inventor: Simon Tian - 2 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivity

[0007] While VoIP applications and multi-TMSI SIMs each exist independently, no prior art system integrates these two technologies into a unified platform wherein connectivity state (active IMSI, network, country) and telephone functions operate as a coordinated system rather than as separate services. Specifically, there is no known system that: (a) uses a multi-IMSI data-only SIM to provide cost-optimized data connectivity across multiple regions; (b) overlays a VoIP application that provides one or more persistent phone numbers entirely decoupled from the underlying IMSI; (c) implements a backend system that links a multi-IMSI SIM / eSIM system with an application-layer VoIP platform and a multi-country numbering system such that multiple international phone numbers remain continuously reachable regardless of which IMSI or mobile network is active; and (d) enables a user to maintain multiple simultaneously active phone numbers from different countries, all accessible through a single SIM / eSIM and a single application, with the ability to select which number is used for outgoing communications.

[0008] Furthermore, conventional approaches require users who need phone numbers in multiple countries to obtain multiple SIM cards, multiple phone plans, and multiple devices, or to rely on expensive international roaming. There is a need for a system that consolidates global voice, messaging, and data services into a single integrated platform operating over a single SIM or eSIM.

[0009] Accordingly, there is a need for a system that combines a multi-IMSI data-only SIM card with a VoIP -based application and a backend coordination platform to allow usage of one or more persistent phone numbers independent of the SIM’s active IMSI, in multiple regions, to ensure seamless communication while optimizing roaming costs.Inventor: Simon Tian - 3 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal ConnectivitySUMMARY OF THE INVENTION

[0010] In accordance with embodiments of the present invention, a system is disclosed for providing seamless global mobile connectivity by integrating a multi-IMSI data-only SIM or eSIM with a VoIP -based communication platform. The system comprises: (i) a multi-IMSI data- only SIM or eSIM that stores a plurality of IMSI profiles corresponding to mobile network operators in different countries or regions, the IMSI profiles being provisioned as data-only subscriptions with the respective MNOs, the SIM being configured to dynamically switch among the plurality of IMSI profiles based on detection of Mobile Country Code (MCC) and Mobile Network Code (MNC) information broadcast by cell towers, with IMSI selection priorities preconfigured based on cost optimization logic; (ii) a VoIP application installed on a mobile device that provides one or more persistent phone numbers from one or more countries, the VoIP application handling all voice calls and text messaging over the data connection provided by the currently active IMSI using SIP -based signaling with media carried over RTP / SRTP, the VoIP application being operable as the default dialer and messaging application on the mobile device; and (iii) a backend system that associates the multi-IMSI SIM or eSIM and the VoIP application with a single user account, manages provisioning of data packages and VoIP services in a synchronized fashion, and maintains a mapping between each assigned phone number and the user account such that calls and messages to any assigned number are routed to the user’s active device regardless of the active IMSI or network.

[0011] In another embodiment, a method is disclosed for providing global roaming by dynamically switching IMSIs on a data-only SIM based on MCC / MNC detection while maintaining continuous VoIP-based communication through persistent phone numbers that are independent of the active IMSI.Inventor: Simon Tian - 4 - Attorney File No. : #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivity

[0012] In yet another embodiment, a method is disclosed for enabling a user to maintain a plurality of simultaneously active phone numbers from different countries on a single SIM or eSIM, wherein incoming calls and messages to any of the plurality of phone numbers are received at all times regardless of the user’s physical location or active IMSI, and wherein the user may select which of the plurality of phone numbers is used for outgoing calls and messages via a user interface within the VoIP application.

[0013] In a further embodiment, a computer-implemented method is disclosed for synchronized provisioning of mobile data and VoIP services, comprising: receiving a purchase event from a user; triggering a webhook to a backend system; creating a user account; activating the SIM / eSIM; provisioning the appropriate data package onto the SIM / eSIM; creating a VoIP account in the application; and enabling the user to select a phone number, such that the active IMSI, user account, VoIP account, and chosen phone number are correctly linked.BRIEF DESCRIPTION OF DRAWINGS

[0014] The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which like parts are given like reference numerals and, wherein:

[0015] FIG. l is a system architecture diagram showing a mobile device equipped with a multi- IMSI data-only SIM interacting with different mobile network operators in different countries, in accordance with embodiments of the invention.

[0016] FIG. 2 is a system architecture diagram showing the backend system in communication with the VoIP application, VoIP servers, PSTN gateways, and mobile network operators, in accordance with embodiments of the invention.Inventor: Simon Tian - 5 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivity

[0017] FIG. 3 is a flowchart illustrating the TMSI switching process, including MCC / MNC- based trigger detection, IMSI selection based on pre-configured network priorities, IMSI switch execution, and VoIP session re-establishment, in accordance with embodiments of the invention.

[0018] FIG. 4 is a flowchart illustrating the call routing process for incoming and outgoing VoIP calls, including multi-number management and caller ID selection, in accordance with embodiments of the invention.

[0019] FIG. 5 is a flowchart illustrating the synchronized provisioning process triggered by a user plan purchase, including webhook-based coordination of SIM / eSIM activation, data package provisioning, VoIP account creation, and phone number assignment, in accordance with embodiments of the invention.

[0020] The images in the drawings are simplified for illustrative purposes and are not depicted to scale. The appended drawings illustrate exemplary configurations of the invention and should not be considered as limiting the scope of the invention, which may admit to other equally effective configurations.

[0021] The appended drawings illustrate exemplary configurations of the invention and, as such, should not be considered as limiting the scope of the invention that may admit to other equally effective configurations. It is contemplated that features of one configuration may be beneficially incorporated in other configurations without further recitation.DETAILED DESCRIPTION OF THE INVENTION

[0022] The embodiments of the disclosure will be best understood by reference to the Figures, wherein like parts are designated by like numerals throughout. It will be readily understood that the components, as generally described and illustrated in the Figures herein, could be arranged and designed in a wide variety of different configurations or be entirely separate. Thus, the Inventor: Simon Tian - 6 - Attorney File No. : #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivityfollowing more detailed description of the embodiments of the system and methods of the disclosure, as represented in the Figures is not intended to limit the scope of the disclosure, as claimed, but is merely representative of possible embodiments of the disclosure

[0023] The following description sets forth numerous embodiments and parameters. It should be recognized, however, that such description is not intended as a limitation on the scope of the present invention but is instead provided as a description of exemplary embodiments. Various modifications to the examples described will be readily apparent to those of ordinary skill in the art, and the general principles defined may be applied to other examples and applications without departing from the spirit and scope of the invention. Thus, the present invention is not intended to be limited to the examples described herein but is to be accorded a scope consistent with the claim

[0024] Referring generally to FIGS. 1 and 2, in one embodiment, the system 100 includes: (i) a multi -IMSI data-only SIM 110 installed in a mobile device 105, the SIM 110 storing a plurality of IMSI profiles 112a, 112b, 112c, ... 112n, each associated with a different mobile network operator (MNO) in a different country or region; (ii) a VoIP application 120 installed on the mobile device 105, the VoIP application 120 providing one or more persistent phone numbers 122a, 122b, 122c, ... 122m from one or more countries and handling all voice calls and text messaging over a data connection provided by the currently active IMSI profile; and (iii) a backend system 130 comprising one or more cloud-based servers that associate the multi-IMSI SIM 110 and the VoIP application 120 with a single user account and coordinate provisioning and number management.

[0025] The system provides a backend-controlled integration of multi-IMSI global connectivity with an application-layer VoIP and multi-number system, such that IMSI selection, network costInventor: Simon Tian - 7 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivityoptimization, and phone number reachability are coordinated as a single system rather than independent services. This integration allows multiple international phone numbers to remain continuously reachable regardless of which IMSI or mobile network is active, while dynamically optimizing connectivity in the background.

[0026] The mobile device 105 may be any computing device capable of supporting a SIM card or eSIM and running a software application, including but not limited to smartphones, tablets, and cellular-enabled laptop computers. The mobile device 105 includes at least one processor, memory, a cellular radio, and a display.

[0027] In various embodiments, the multi-IMSI data-only SIM 110 may be embodied as a physical SIM card or as an eSIM (embedded SIM) profde provisioned within the mobile device 105. The IMSI profiles on the SIM 110 are provisioned as data-only subscriptions with the respective MNOs. The SIM 110 does not provide circuit-switched voice or traditional SMS capabilities. All voice and messaging services are provided by the VoIP application 120 operating over the data connection.

[0028] Multi-IMSI Data-Only SIM

[0029] Referring to FIG. 1, the multi-IMSI SIM 110 is preloaded with a plurality of IMSI profiles 112a-l 12n covering different global regions. In a preferred embodiment, a single SIM or eSIM supports approximately 1 to 12 IMSI profiles. In one exemplary implementation, the SIM 110 contains 4 IMSI profiles from 4 different MNOs, collectively providing data coverage in over 100 countries and regions. The number and composition of IMSI profiles may change over time as MNO partnerships are added or removed. Each IMSI profile 112 includes an IMSI number comprising a Mobile Country Code (MCC), a Mobile Network Code (MNC), and a Mobile Subscriber Identification Number (MSIN) that together uniquely identify the subscriber to aInventor: Simon Tian - 8 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivityspecific MNO in a specific country. Each IMSI profile 112 further includes authentication credentials (e.g., Ki and OPc values) necessary to authenticate the subscriber with the corresponding MNO.

[0030] In operation, as the mobile device 105 moves from a first country (Country A) to a second country (Country B), the SIM 110 detects the change in location by monitoring the MCC and / or MNC broadcast by cell towers in the vicinity of the mobile device 105. Upon detecting a change in MCC / MNC indicating that the device has entered a new country or region, the SIM 110 transitions from a first IMSI profile 112a associated with an MNO in Country A to a second IMSI profile 112b associated with an MNO in Country B. Similarly, if the user moves to a third country (Country C), the SIM 110 transitions to a third IMSI profile 112c operable to communicate with an MNO in Country C.

[0031] In practice, IMSI switches occur relatively infrequently, typically only when a user first crosses into a new country or region (e.g., upon landing from a flight or crossing a land border). During an IMSI switch, the data connection is temporarily interrupted as the SIM 110 detaches from the current MNO network and attaches to the new MNO network. A typical IMSI switch may take approximately 1 to 3 minutes or faster to complete. If the user is on an active VoIP call during the switch, the call will be interrupted and the user may reinitiate the call once the switch is complete and the new data connection is established.

[0032] The system supports two methods of IMSI switching:(A) Device-Initiated Switch: The SIM 110 itself contains multiple IMSI profiles and autonomously determines which IMSI profile to use based on network availability and operator priorities pre-programmed on the SIM. The SIM 110 monitors MCC / MNC information broadcast by cell towers and, upon detecting a triggering event such as entry into a new country, initiates the IMSI switch by updating the activeInventor: Simon Tian - 9 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal ConnectivityIMSI stored in the STM’s Elementary Files (EF). Operator priorities are pre-configured on the SIM such that, for a given country or region, the SIM selects the preferred MNO first (typically the lowest-cost network in terms of cost per gigabyte of data), and if that network is unavailable, falls back to the next preferred network, and so on in a hierarchical fashion. (B) Remote or Server- Initiated Switch: For eSIMs, an SM-DP+ (Subscription Manager - Data Preparation) server or carrier backend can push a new profile or command the SIM to switch to a different IMSI profile. The SIM 110 downloads a new profile or activates a different IMSI profile based on the remote command.

[0033] Cost Optimization

[0034] In the preferred embodiment, the IMSI selection priorities are pre-configured on the SIM 110 based on cost optimization. For each supported country or region, the system determines which available MNO offers the lowest cost per gigabyte of data and programs that MNO’s IMSI profile as the highest-priority selection for that region. If the highest-priority network is unavailable (e.g., due to poor signal or network outage), the SIM 110 falls back to the next lowest- cost available network in a pre-configured hierarchical sequence.

[0035] The cost optimization priorities may be updated over time via OTA (over-the-air) updates to the SIM 110. For example, if a particular MNO in a given country offers the cheapest data rates but has deficient coverage, the system operator may update the IMSI priorities via OTA to instead prioritize a different MNO with better coverage in that country, even if its per-gigabyte cost is higher. This flexibility allows the system to balance cost optimization with network quality considerations without requiring physical replacement of the SIM.

[0036] Over-the-Air (OTA) IMSI Profile ManagementInventor: Simon Tian - 10 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivity

[0037] In addition to preloaded IMSI profiles, the system supports over-the-air (OTA) updating of IMSI profiles on the SIM 110 or eSIM. OTA updates enable the addition of new IMSI profiles, the removal or deactivation of IMSI profiles, and the modification of existing IMSI profile parameters including operator priority rankings. This OTA capability provides operational flexibility, allowing the service provider to expand geographic coverage and optimize carrier partnerships without requiring physical replacement or reshipment of SIM cards or eSIMs.

[0038] For physical SIM cards, OTA updates may be performed using the standard SIM OTA protocol defined in GSM 03.48 / 3GPP TS 31.115, which defines secure message formatting, encryption, and integrity checks for SIM updates over the mobile network. Update commands are delivered to the SIM via SMS, encrypted and authenticated by the SIM.

[0039] For eSIMs, OTA updates are performed using the GSMA eSIM specifications, including SM-DP+ (Subscription Manager - Data Preparation) for securely provisioning profiles to the SIM, and SM-DS (Subscription Manager - Discovery Service) to help the SIM locate the appropriate SM-DP+ server. Messages may be sent via SMS, HTTPS, or IMS signaling channels, encrypted and authenticated by the SIM.

[0040] IMSIs can be both added and removed remotely. Adding a new IMSI involves downloading and activating a new profile on the SIM. Removing an IMSI involves deactivating or deleting an existing profile to free space. OTA capability works on both physical SIM cards and eSIMs.

[0041] VoIP Application

[0042] Referring to FIG. 2, the VoIP application 120 is a software application installed on the mobile device 105 that provides voice calling and messaging services over the IP data connection established by the currently active IMSI profile of the SIM 110. The VoIP application 120Inventor: Simon Tian - 11 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivityoperates independently of the selected IMS! profde and is agnostic to IMSI changes; because it communicates over the IP data layer, it functions identically regardless of which underlying IMSI profile is providing the data connection. There is no direct linkage between the active IMSI and the VoIP application; the backend system 130 simply associates a particular SIM / eSIM with a user account along with a corresponding VoIP account, and this association ensures that the user’s device receives calls and messages for their selected phone numbers regardless of which IMSI is active.

[0043] The VoIP application 120 uses SIP (Session Initiation Protocol) for call signaling, with media carried over RTP (Real-time Transport Protocol) and SRTP (Secure Real-time Transport Protocol). The VoIP application 120 communicates with one or more VoIP servers 140, which in turn connect to the PSTN via PSTN gateways 150 for calls to and from traditional phone numbers.

[0044] In the preferred embodiment, the VoIP application 120 provides the following features: (a) voice call routing through VoIP servers 140, enabling the user to make and receive phone calls to and from PSTN phone numbers worldwide; (b) SMS and MMS message delivery via the VoIP / messaging backend, wherein the backend maps each phone number to the user account and routes messages over IP to the application, allowing users to send and receive texts and multimedia messages regardless of the active IMSI or physical location; (c) push notifications for incoming calls and messages, utilizing platform-specific push notification services such as Apple Push Notification Service (APNs) for iOS devices and Firebase Cloud Messaging (FCM) for Android devices; (d) support for multiple simultaneously active phone numbers 122a-122m from different countries; (e) the ability to function as the default dialer and messaging application on the mobile device 105, intercepting and routing all incoming and outgoing calls through the VoIPInventor: Simon Tian - 12 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivityinfrastructure; (f) visual voicemail; and (g) a user interface for managing phone numbers, selecting the active outgoing number, and configuring communication preferences.

[0045] In a preferred embodiment, the VoIP application 120 is configured as the default dialer on the mobile device 105. On Android devices, this may be implemented using the Android ConnectionService API or by registering the application as the default phone application through the Android TelecomManager framework. On iOS devices, this may be implemented using the Apple CallKit framework, which allows the VoIP application to integrate with the native phone interface and handle incoming and outgoing calls through the VoIP infrastructure while presenting a native call experience to the user. When configured as the default dialer, all incoming and outgoing calls are automatically routed through the VoIP application 120, ensuring that the user’s persistent phone number(s) are used for all communications regardless of the underlying IMS1.

[0046] Multi -Numb er Management

[0047] In the preferred embodiment, the system enables a user to maintain a plurality of simultaneously active phone numbers 122a- 122m from different countries on a single user account, accessible through a single SIM 110 or eSIM and a single VoIP application 120. Each phone number 122 may be a new number selected by the user from available area codes in a supported country, or an existing number ported into the system from another carrier. Multiple phone numbers, including domestic and international DIDs (Direct Inward Dialing numbers), are associated with a single user account in the backend system 130.

[0048] The backend system 130 maintains a mapping between each assigned phone number and the user’s account on the VoIP application 120, ensuring that calls and messages to any assigned number are routed to the user’s active device regardless of the active IMSI or network.Inventor: Simon Tian - 13 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal ConnectivityBecause the phone numbers are VoIP -based virtual numbers hosted on VoIP servers 140, they are entirely decoupled from the SIM 110 and its IMSI profiles; the phone numbers remain active and reachable regardless of which IMSI profile is currently active on the SIM 110 and regardless of the user’s physical location.

[0049] In operation, the user can receive incoming calls and text messages on any of the plurality of phone numbers 122a-122m at all times. When a call is placed to any of the user’s phone numbers (e.g., a call to the user’s UK number +44-XXXX-XXXXXX while the user is physically located in Thailand using a Thai IMSI), the call is received by the VoIP server 140 associated with that phone number, routed through the VoIP infrastructure to the VoIP application 120 on the mobile device 105 over the IP data connection provided by the currently active IMSI, and presented to the user as an incoming call with caller ID indicating which of the user’ s numbers was dialed. The IMSI and underlying mobile network do not affect call delivery, as the VoIP layer handles reachability independently.

[0050] For outgoing calls and messages, the VoIP application 120 provides a user interface element (e.g., a toggle, dropdown selector, or number picker) that allows the user to select which of the plurality of phone numbers 122a-122m is used as the outgoing caller ID. The selected phone number is transmitted to the VoIP server 140 as part of the SIP call setup signaling, and the VoIP server 140 sets the outgoing caller ID (CLI - Calling Line Identification) to the selected phone number. This enables outgoing calls and messages to appear as local calls to the recipient, regardless of the user’s physical location. For example, a user physically located in Canada may place a call using their UK phone number, and the recipient in the UK will see a local UK number on their caller ID.Inventor: Simon Tian - 14 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivity

[0051] In various embodiments, certain countries may require KYC (Know Your Customer) identity verification before a phone number from that country can be provisioned to the user. The VoIP application 120 integrates identity verification services during the number selection process; if the user chooses a number that requires KYC, the application prompts the user to complete identity verification in compliance with local regulatory requirements for that country.

[0052] Backend System

[0053] Referring to FIG. 2, the backend system 130 is a cloud-based platform hosted on major cloud infrastructure (e.g., AWS) and may be deployed across multiple geographic regions and points of presence to reduce latency and improve performance for VoIP calls. The backend system 130 is operable to perform the following functions: (a) User Account Management: The backend system 130 associates a particular SIM / eSIM with a user account along with a corresponding VoIP account. This association ensures that the user’s device receives calls and messages for their selected phone numbers, regardless of which IMSI is active. There is no direct linkage between the active IMSI and the VoIP account; rather, the backend system 130 links the SIM / eSIM, the user account, the VoIP account, and the assigned phone numbers as a unified record, (b) Synchronized Provisioning: Referring to FIG. 5, when a user completes a purchase of a phone plan, the purchase event triggers a webhook from the commerce system to the backend system 130. The backend system 130 then: (1) creates a user account linked to the user’s email; (2) activates the SIM / eSIM for the user; (3) provisions the appropriate data package onto the SIM / eSIM; (4) creates a VoIP account in the VoIP application 120, after which the user can select a phone number of their choice. This ensures that the active IMSI, user account, VoIP account, and chosen phone number are correctly linked, so calls and messages are routed to the user’s device regardless of location or IMSI. (c) Multi-Number Provisioning and LifecycleInventor: Simon Tian - 15 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal ConnectivityManagement: The backend system 130 manages the provisioning, activation, deactivation, and porting of phone numbers across multiple countries. The system maintains a mapping database that associates each phone number with a user account and VoIP routing configuration. Costs associated with inbound and outbound calls and messages are incorporated into flat monthly rates that customers pay, rather than being charged on a metered basis, (d) IMSI Profile Management: The backend system 130 manages the OTA updating of IMSI profiles on the SIM 110 or eSIM, including adding new IMSI profiles when new MNO partnerships are established, removing IMSI profiles when partnerships are discontinued, and updating operator priority rankings to optimize cost and coverage. For eSIMs, the backend system 130 communicates with the SM-DP+ server to push profile updates.

[0054] Number Porting

[0055] In various embodiments, the system supports porting of existing phone numbers from other carriers into the VoIP platform. When a user requests to port an existing number, the system initiates a port request with a third-party provider (e g., Sinch, Inteliquent, DIDWW, or similar providers). The porting process typically takes 2 to 5 business days and varies depending on the country. Once the number is ported, it is associated with the VoIP platform only and no longer retains any association with the previous PSTN provider. The ported number is fully integrated into the multi -number management system described above, allowing the user to receive calls and messages on the ported number through the VoIP application 120 regardless of which IMSI profile is active on the SIM 110.

[0056] Data Tethering and Mobile Hotspot

[0057] In various embodiments, the mobile device 105 may share the data connection provided by the multi-IMSI SIM 110 with other devices through tethering or mobile hotspot functionality.Inventor: Simon Tian - 16 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal ConnectivityBecause the STM 110 provides a data-only connection that is optimized for cost and coverage through pre-configured IMSI selection priorities, the tethering functionality benefits from the same cost optimization and IMSI switching as the primary device.

[0058] Example Operation

[0059] The following example illustrates the operation of the system in a typical use case. A user based in the United States subscribes to the service and receives a multi -IMSI SIM 110 or eSIM provisioned with IMSI profiles for multiple MNOs covering over 100 countries. Upon purchase, a webhook triggers the backend system 130 to create the user account, activate the SIM / eSIM, provision the data package, and create a VoIP account. The user selects a U.S. phone number (+1-XXX-XXX-XXXX) and a UK phone number (+44-XXXX-XXXXXX) through the VoIP application 120.

[0060] While in the United States, the SIM 110 uses a U.S. -based IMSI profile 112a to connect to a local MNO for data service. The VoIP application 120 functions as the default dialer on the user’s mobile device 105. All incoming and outgoing calls are routed through the VoIP infrastructure using the SIP / RTP data connection. The user receives calls on both the U.S. and UK numbers simultaneously.

[0061] When the user travels to the United Kingdom, the SIM 110 detects the change in MCC broadcast by UK cell towers. Based on pre-configured IMSI priorities, the SIM 110 selects the lowest-cost UK IMSI profile 112b and initiates the switch. The data connection is temporarily interrupted for approximately 1 to 3 minutes as the STM detaches from the U.S. network and attaches to the UK network. Once the new data connection is established, the VoIP application 120 reconnects to the VoIP servers 140 and resumes full service. Throughout this process, theInventor: Simon Tian - 17 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivityuser’s U.S. and UK phone numbers remain assigned to the account, and any calls placed during the brief switch period are handled by voicemail or retry logic.

[0062] If the user subsequently travels to Thailand, the SIM 110 detects the MCC change and switches to a Thailand-based IMSI profile 112c. Again, the VoIP application 120 resumes full service once the new data connection is established. Throughout this journey, the user’s phone numbers have remained constant, the user has not needed to purchase additional SIM cards or plans, and the data connection has been automatically optimized for cost in each region through pre-configured IMSI priorities.

[0063] FIG. 3 is a flowchart illustrating the IMSI switching process performed by the system when the mobile device 105 crosses into a new geographic region. The flowchart proceeds as follows:

[0064] At step 300, the mobile device 105 is operating normally on an active IMSI profile via a data connection. The VoIP application 120 is connected to the VoIP servers 140 and the user’s phone numbers 122a-122m are active and reachable.

[0065] At step 302, the SIM 110 detects a change in Mobile Country Code (MCC) and Mobile Network Code (MNC) from a cell tower broadcast, indicating that the mobile device 105 has entered a new country or region. This detection is performed by the SIM 110 monitoring the MCC / MNC information broadcast by nearby cell towers.

[0066] At decision step 304, the system determines whether an IMSI switch is needed based on the detected MCC / MNC change. If no switch is needed (e g., the current IMSI already covers the detected region), the process returns to step 300 and the device continues operating on the current IMSI profile (shown by the “No” path looping back to step 300).Inventor: Simon Tian - 18 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivity

[0067] If an IMS! switch is needed (the “Yes” path from decision step 304), the process proceeds to step 306, where the SIM 110 evaluates the pre-configured IMSI selection priorities for the new country or region. These priorities are pre-programmed on the SIM, ranking available IMSI profiles by cost per gigabyte of data for each supported region.

[0068] At decision step 308, the system determines whether the preferred (lowest-cost) network for the new region is available. If the preferred network is not available (the “No” path), the process proceeds to step 309, where the SIM 110 falls back to the next most preferred IMSI profile in the sequence. From step 309, the process continues to step 310. If the preferred network is available (the “Yes” path from decision step 308), the process proceeds directly to step 310.

[0069] At step 310, the SIM 110 executes the IMSI switch by detaching from the current MNO network and updating the SIM to the selected IMSI profile.

[0070] At step 312, the data connection is temporarily interrupted. This interruption typically lasts approximately 1 to 3 minutes. If the user is on an active VoIP call at the time of the switch, the call is interrupted.

[0071] At step 314, the SIM 110 attaches to the new MNO network using the selected IMSI profile and establishes a new data connection.

[0072] At step 316, the VoIP application 120 detects the availability of the new data connection and automatically reconnects to the VoIP servers 140, resuming voice and messaging service.

[0073] FIG. 4 is a flowchart illustrating the call routing process for both incoming and outgoing VoIP calls. The flowchart is divided into two parallel columns: the left column illustrates the incoming call flow and the right column illustrates the outgoing call flow. A note at the bottom of the figure states that all call routing occurs over the IP data connection provided by the currentlyInventor: Simon Tian - 19 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivityactive IMS! profile on the multi-IMSI data-only STM 110, and that phone numbers 122a-122m remain reachable regardless of which IMSI profile is active or the user’s physical location.

[0074] The incoming call flow (left column) proceeds as follows: At step 400, an external caller dials one of the user’s phone numbers. At step 402, the call is received by VoIP server 140b associated with the dialed number; the call enters the VoIP infrastructure via PSTN gateway 150. At step 404, the backend system 130 looks up the user account mapped to the dialed number and identifies the target mobile device 105. At step 406, a push notification is sent to the VoIP application 120. At step 408, the VoIP application 120 activates and establishes a VoIP session to VoIP server 140a over the data connection provided by the currently active IMSI. At step 410, the incoming call is displayed to the user, with the caller ID shown and an indication of which of the user’s numbers 122a-122m was dialed. At step 412, a VoIP media stream is established, with audio routed from the caller through PSTN gateway 150, through VoIP servers 140, to the mobile device 105. The flow concludes with the call connected.

[0075] The outgoing call flow (right column) proceeds as follows: At step 420, the user initiates an outgoing call via the VoIP application 120. At step 422, the user selects an outgoing phone number via a UI toggle (e.g., +44-XXXX from numbers 122a-122m). At step 424, the user enters the recipient’s phone number and initiates the call. At step 426, the VoIP application 120 sends the call to VoIP server 140a over the data connection from the currently active IMSI on SIM 110. At step 428, VoIP server 140a sets the outgoing caller ID (CLI - Calling Line Identification) to the phone number selected by the user (e.g., +44-XXXX). At step 430, the call is routed to VoIP server 140b (terminating server). At step 432, PSTN gateway 150 delivers the call to the recipient on the PSTN, with the caller ID appearing as a local number to the recipient. The flow concludes with the call connected.Inventor: Simon Tian - 20 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivity

[0076] FTG. 5 is a flowchart illustrating the provisioning process performed when a new user purchases a mobile service plan. The flowchart depicts the sequential steps coordinated by the backend system 130 to link the data-only SIM, user account, VoIP account, and phone number(s) as a unified record.

[0077] At step 500, the user purchases a mobile service plan via a commerce system. At step 502, the purchase event triggers a webhook to the backend system 130, notifying the backend of the new purchase and the associated user.

[0078] At step 504, the backend system 130 creates a user account linked to the user’s email address. At step 506, the backend system 130 activates the multi-IMSI data-only SIM 110 (or eSIM) for the user and associates the SIM with the newly created user account. At step 508, the backend system 130 provisions the appropriate data package onto the SIM 110 via the SIM management platform 135, enabling the SIM to provide data connectivity through its preconfigured IMSI profiles.

[0079] At step 510, the backend system 130 creates a VoIP account in the VoIP application 120 and associates the VoIP account with the user account. At step 512, the user selects one or more phone numbers from available countries and area codes through the VoIP application 120. If the user selects a phone number from a country that requires KYC (Know Your Customer) identity verification, the application prompts the user to complete identity verification before the number is provisioned.

[0080] At step 514, all components are linked in the backend system 130: the active IMSI on the SIM 110, the user account, the VoIP account, and the chosen phone number(s) 122 are correctly associated as a unified record. This linkage ensures that calls and messages to any of theInventor: Simon Tian - 21 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivityuser’s phone numbers are routed to the user’s device regardless of which IMSI profde is active or the user’s physical location.

[0081] At step 516, the provisioning process is complete and the service is ready. The user has data connectivity via the multi-IMSI data-only SIM 110 and VoIP service via the VoIP application 120. Calls and messages are routed to the user’s device regardless of the active IMSI profile.

[0082] The foregoing description sets forth numerous embodiments and parameters. It should be recognized, however, that such description is not intended as a limitation on the scope of the present invention but is instead provided as a description of exemplary embodiments. Various modifications to the examples described will be readily apparent to those of ordinary skill in the art, and the general principles defined may be applied to other examples and applications without departing from the spirit and scope of the invention. Thus, the present invention is not intended to be limited to the examples described herein but is to be accorded a scope consistent with the claims.

[0083] The particular implementations shown and described herein are illustrative examples of the invention and are not intended to otherwise limit the scope of the invention in any way. For the sake of brevity, conventional aspects of the system may not be described in detail. Furthermore, the connecting lines or connectors shown in the various figures are intended to represent exemplary functional relationships and / or physical or logical couplings between the various elements. Many alternative or additional functional relationships, physical connections, or logical connections may be present in a practical device. Moreover, no item or component is essential to the practice of the invention unless the element is specifically described as “essential” or “critical.Inventor: Simon Tian - 22 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivity

Claims

CLAIMSWhat is claimed is:What is claimed is:

1. A system for providing global mobile connectivity, the system comprising:a mobile device containing a data-only SIM configured to store a plurality of IMSI profiles and to dynamically switch among the plurality of IMSI profiles to provide data connectivity across a plurality of geographic regions;a VoIP application installed on the mobile device containing the data-only SIM, the VoIP application configured to provide at least one persistent phone number that is independent of the plurality of IMSI profiles and to route voice communications and messages over a data connection provided by a currently active IMSI profile, the VoIP application operating independently of which IMSI profile is active such that there is no direct linkage between the active IMSI profile and the VoIP application; anda backend system configured to associate the data-only SIM and the VoIP application with a single user account as a coordinated system, the backend system maintaining a mapping between each persistent phone number and the user account such that the at least one persistent phone number remains reachable regardless of which IMSI profile is currently active and regardless of a physical location of the mobile device.

2. The system of claim 1, wherein each IMSI profile of the plurality of IMSI profiles is provisioned as a data-only subscription with a different mobile network operator, and the data-only SIM does not provide voice or SMS capabilities.

3. The system of claim 1, wherein the dynamic switching among the plurality of IMSI profiles is triggered by the data-only SIM detecting a change in Mobile Country Code orInventor: Simon Tian - 23 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal ConnectivityMobile Network Code information broadcast by a cell tower, indicating that the mobile device has entered a new geographic region.

4. The system of claim 1, wherein the data-only SIM stores pre-configured IMSI selection priorities such that, for a given geographic region, the data-only SIM selects a preferred IMSI profile based on lowest cost per unit of data, and if the preferred IMSI profile is unavailable, falls back to a next preferred IMSI profile in a hierarchical sequence.

5. The system of claim 1, wherein the VoIP application is configured to provide a plurality of simultaneously active phone numbers from a plurality of different countries, the plurality of phone numbers being mapped to the single user account, and wherein the VoIP application is configured to receive incoming calls and messages on any of the plurality of phone numbers regardless of which IMSI profile is currently active.

6. The system of claim 5, wherein the VoIP application provides a user interface element for selecting which of the plurality of phone numbers is used as an outgoing caller identification for outgoing calls and messages, such that outgoing communications appear to originate from a phone number local to a selected country regardless of the physical location of the mobile device.

7. The system of claim 1, wherein the data-only SIM supports two methods of IMSI switching: a device-initiated switch in which the data-only SIM autonomously selects an IMSI profile based on network availability and pre-programmed operator priorities; and a remote server-initiated switch in which a server pushes a new profile or commands the data-only SIM to switch IMSI profiles.

8. The system of claim 1, wherein the backend system is configured to perform synchronized provisioning by, in response to a user purchase event triggering a webhook:Inventor: Simon Tian - 24 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivitycreating a user account; activating the data-only SIM; provisioning a data package onto the data-only SIM; and creating a VoIP account in the VoIP application, after which the user selects a phone number, such that the active IMSI, user account, VoIP account, and chosen phone number are linked.

9. The system of claim 1, wherein the data connection is temporarily interrupted during a switch between IMSI profiles, and the VoIP application is configured to automatically reconnect to VoIP servers and resume service upon establishment of a new data connection after the10. A method for providing global mobile connectivity, the method comprising:providing a mobile device with a data-only SIM storing a plurality of IMSI profiles, each IMSI profile associated with a different mobile network operator;installing a VoIP application on the mobile device, the VoIP application providing at least one persistent phone number independent of the plurality of IMSI profiles, the VoIP application operating independently of which IMSI profile is active such that there is no direct linkage between the active IMSI profile and the VoIP application;associating, by a backend system, the data-only SIM and the VoIP application with a single user account such that connectivity state and telephony functions operate as a coordinated system;detecting a change in geographic region requiring an IMSI switch; switching the data-only SIM from a first IMSI profile to a second IMSI profile to establish a new data connection; andreconnecting, by the VoIP application, to VoIP servers over the new data connection to resume voice and messaging service through the at least one persistentInventor: Simon Tian - 25 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivityphone number, without requiring user intervention to maintain the at least one persistent phone number.

11. The method of claim 10, wherein detecting the change in geographic region comprises the data-only SIM detecting a change in Mobile Country Code or Mobile Network Code information broadcast by cell towers.

12. The method of claim 10, wherein the switching is performed based on pre-configured IMSI selection priorities that prioritize the IMSI profde offering the lowest cost per unit of data for the new geographic region, with fallback to a next lowest-cost IMSI profde if the preferred IMSI profde is unavailable.

13. The method of claim 10, further comprising:receiving, by the VoIP application, incoming calls on a plurality of simultaneously active phone numbers from a plurality of different countries, regardless of which IMSI profde is currently active on the data-only SIM, wherein the IMSI and underlying mobile network do not affect call delivery.

14. The method of claim 13, further comprising:selecting, via a user interface of the VoIP application, one of the plurality of phone numbers for use as an outgoing caller identification; and placing an outgoing call using the selected phone number as the caller identification, such that the outgoing call appears to originate from a phone number local to a country associated with the selected phone number.

15. The method of claim 10, wherein the data connection is temporarily interrupted during the switching, and the VoIP application automatically reconnects to VoIP servers upon establishment of the new data connection.Inventor: Simon Tian - 26 - Attorney File No. : #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivity16. The method of claim 10, further comprising: updating, over-the-air, the plurality of IMSI profiles stored on the data-only SIM to add a new IMSI profile or remove an existing IMSI profile without physical replacement of the SIM.

17. A system for managing a plurality of phone numbers across multiple countries on a single mobile device, the system comprising:a data-only SIM installed in a mobile device, the data-only SIM configured to provide a data connection by dynamically selecting among a plurality of IMSI profiles;a VoIP application installed on the mobile device, the VoIP application configured to:maintain a plurality of simultaneously active phone numbers from a plurality of different countries, each phone number being a virtual phone number hosted on a VoIP server and decoupled from the data-only SIM such that there is no direct linkage between an active IMSI profile and the plurality of phone numbers;receive incoming calls and messages addressed to any of the plurality of phone numbers at all times, regardless of which IMSI profile is currently active on the data-only SIM and regardless of the physical location of the mobile device;provide a user interface for selecting which of the plurality of phone numbers is used as an outgoing caller identification for outgoing calls and messages; androute voice communications and messages through a VoIP infrastructure using the data connection provided by the data-only SIM; anda backend system configured to map the plurality of phone numbers to a single user account and associate the data-only SIM and the VoIP application with the singleInventor: Simon Tian - 27 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivityuser account such that connectivity state and telephony functions operate as a coordinated system.

18. The system of claim 17, wherein the plurality of phone numbers includes at least one ported phone number that was transferred from a previous carrier to the VoIP server, the ported number being associated with the VoIP platform only and no longer retaining any association with the previous PSTN provider.

19. The system of claim 17, wherein the VoIP application is configured as a default dialer on the mobile device, such that all incoming and outgoing calls are automatically routed through the VoIP infrastructure while presenting a native call interface to the user.

20. The system of claim 17, wherein the backend system is further configured to enforce compliance with verification requirements for phone numbers from countries that require identity verification, the VoIP application integrating identity verification services during a number selection process.

21. The system of claim 17, wherein the VoIP application routes voice communications using SIP -based signaling, and outgoing calls placed using a phone number from a first country appear to a recipient as originating from a local number in the first country by setting the outgoing caller ID to the selected phone number in SIP call setup signaling.Inventor: Simon Tian - 28 - Attorney File No.: #3103 Title: System And Method for Combining Multi-IMSIData-Only Sim with Voice-Over-IP Platform For SeamlessGlobal Connectivity

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