A communication service implementation method and device for a VoLTE network terminal roaming to a GSM network
By connecting with the GSM network through cross-network service function entities, the problem of VoLTE terminals being unable to roam to the GSM network after the CS domain is decommissioned is solved, enabling VoLTE terminals to provide normal communication services on the GSM network and reducing maintenance and operation costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI XINFANG INTELLIGENT SYST CO LTD
- Filing Date
- 2026-03-25
- Publication Date
- 2026-05-29
AI Technical Summary
After the CS domain is decommissioned, VoLTE terminals will be unable to provide communication services when roaming on overseas GSM networks.
By interfacing with the GSM network through cross-network service function entities, it handles communication services roaming to the GSM network, including authentication, registration, voice, SMS and data services, and realizes cross-network signaling conversion and service processing.
It enables VoLTE terminals to provide normal communication services on GSM networks, reduces the need for VoLTE network element upgrades, and lowers maintenance and operation costs.
Smart Images
Figure CN122120750A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of communications, and more specifically, to a method for implementing communication services when a Long Term Evolution Voice Bearer (VoLTE) network terminal roams to a Global System for Mobile Communications (GSM) network. Background Technology
[0002] With the continuous development of the communications industry, VoLTE network coverage has been achieved across China, and traditional circuit-switched domains (CS) that are not VoLTE networks are gradually being phased out to reduce operator costs.
[0003] When a CS domain is still active, a VoLTE terminal can continue to register under a domestic CS domain while roaming on a non-VoLTE network. Once a CS domain is deactivated, VoLTE terminals will no longer be able to be used under a CS domain in overseas roaming locations. Summary of the Invention
[0004] This application provides a method for implementing communication services when a VoLTE network terminal roams to a GSM network, in order to solve the communication service problem when a VoLTE terminal roams to a GSM network after the CS domain is decommissioned.
[0005] The first aspect of this application provides a method for implementing communication services when a VoLTE (Voice over LTE) network terminal roams to a GSM (Global System for Mobile Communications) network, the method comprising:
[0006] On the cross-network service function entity side used to handle communication services roaming from VoLTE network to GSM network,
[0007] The cross-network service function entity receives an update location request message initiated from the GSM network side. This update location request message carries mobile subscription identification information.
[0008] Based on the mobile subscription identifier information, determine whether the terminal is allowed to register on the GSM network.
[0009] Where permitted, an Insert User Data Request message is sent to the GSM network side. This message carries subscription information and SCCP source global address (GT) information from the Signalling Connection Control (SCCP) section, so that the GSM network side records the mobile subscription identifier information as the terminal number and records the SCCP source GT information as the terminal's home address information. The SCCP source GT information is the address information used as the Home Location Register (HLR) across network service function entities.
[0010] The system receives an Insert User Data Response message from the GSM network side and sends an Update Location Response message to the GSM network side to complete the initial registration with the GSM network. The Insert User Data Response message carries SCCP target GT information, which is the address information of the cross-network service function entity. The Insert User Data Response message is sent to the cross-network service function entity by the first signaling transfer point through GT addressing.
[0011] in,
[0012] The message is transmitted across networks via a signaling transfer point.
[0013] As one possible implementation, after sending the location update response message to the GSM network side, the process further includes:
[0014] Send a third-party registration SMS message to the SMS service center on the VoLTE network side. The header field of the third-party registration SMS message includes the terminal roaming location information, so that the SMS service center records the cross-network service function entity address as the service call session control function (S-CSCF) address registered by the terminal.
[0015] The communication services roaming from a VoLTE network to a GSM network include at least one of the following services:
[0016] Authentication services used for terminal authentication.
[0017] Update registration service used for location updates between different roaming network elements in a GSM network
[0018] Location clearing service is used to clear location information after leaving the GSM network.
[0019] Caller voice service in GSM network
[0020] SMS service for callers and recipients in GSM networks
[0021] Data services in GSM networks
[0022] Access control services in GSM networks.
[0023] As one possible implementation method, the authentication service is implemented in the following manner:
[0024] The cross-network service function entity receives an authentication request message from the GSM network side. This authentication request message carries GSM network mobile subscription identification information.
[0025] In response to the authentication request message, based on the GSM network mobile subscription identifier information in the authentication request message, an authentication response message is sent to the GSM network side. The authentication response message carries an authentication vector group corresponding to the GSM network mobile subscription identifier information to authenticate the terminal.
[0026] As one possible implementation, the update registration service is implemented in the following manner:
[0027] When a terminal switches from the first roaming network element to the second roaming network element in a GSM network
[0028] The cross-network service function entity receives an update location request message from the second roaming network element on the GSM network side, and determines whether the terminal is allowed to log in to the second roaming network element.
[0029] If permitted, send a location cancellation request message to the first roaming network element.
[0030] Receive a location cancellation response message from the first roaming network element.
[0031] In response to the location cancellation response message, the terminal's location information is updated to the location information of the second roaming network element, and an insert user data request message is sent to the second roaming network element. This user data request message carries SCCP source GT information, which is the address information of the cross-network service function entity as the home location register, so that: the second roaming network element records the terminal's home location register information as the SCCP source GT information.
[0032] The system receives an Insert User Data Response message from the second roaming network element. This message carries SCCP target GT information, which is the address information of the cross-network service function entity as the home location register.
[0033] In response to the user data response message, an update location response message is sent to the second roaming network element. This update location response message carries SCCP source GT information, which is the address information of the cross-network service function entity as the home location register. A third-party SMS registration message is sent to the SMS service center on the VoLTE network side. The header field of this third-party SMS registration message includes the terminal roaming location information, so that the SMS service center records the cross-network service function entity address as the S-CSCF address registered by the terminal.
[0034] As one possible implementation, the location clearing service is implemented in the following manner:
[0035] The cross-network service function entity receives a cleanup mobile station request message from the GSM network side.
[0036] Based on the address from which the mobile station cleanup request message originated, determine whether it is the recorded registration address.
[0037] If so, a cleanup mobile station response message is returned to the GSM network side.
[0038] If not, a message to cancel third-party registration via SMS is sent to the SMS service center on the VoLTE network side, causing the SMS service center on the VoLTE network side to return a response message to cancel third-party registration via SMS. Based on this response message, the cross-network service function entity determines that the terminal is not roaming on the GSM network.
[0039] As one possible implementation, the called party voice service is implemented in the following manner:
[0040] When the terminal is the called party and roaming on a GSM network,
[0041] The cross-network service function entity receives a telephone number mapping query request message from the VoLTE network side. This request message is sent by the VoLTE network side's called party home telephone number mapping domain name system in response to a preselected telephone number mapping query request message from the called party home S-CSCF. Specifically, the called party home S-CSCF receives a transferred called party voice service and triggers a multimedia call service request message to the telephone number mapping domain name system. The telephone number mapping domain name system finds that the terminal is not currently registered on the VoLTE network side and returns the preselected access code and called number to the called party home S-CSCF, so that the called party home S-CSCF sends a preselected telephone number mapping query request message to the called party home telephone number mapping domain name system.
[0042] The cross-network service function entity responds to the phone number mapping query request message by converting it into a roaming number provision request message according to the MAP protocol and sending it to the GSM network side.
[0043] The cross-network service function entity receives a roaming number provision response message from the GSM network side. This message carries the GSM network roaming number that the GSM network provides to the terminal.
[0044] The cross-network service function entity obtains the GSM network roaming number from the roaming number response message, constructs a phone number mapping query message carrying the GSM network roaming number, and sends it to the VoLTE network so that the VoLTE network can conduct voice services with the GSM network based on the GSM network roaming number.
[0045] As one possible implementation, the calling and called SMS service is implemented in the following manner:
[0046] When the terminal is the calling party and roaming on a GSM network,
[0047] The cross-network service function entity receives an uplink forwarding SMS request message from the GSM network side. This uplink forwarding SMS request message carries SCCP destination GT information, which is the address of the cross-network service function entity as the SMS service center.
[0048] The cross-network service function entity responds to the uplink forwarding SMS request message by performing protocol conversion on the uplink forwarding SMS request message and sending the calling message request to the VoLTE network-side calling SMS service center, so that the calling SMS service center forwards the calling message request to the called SMS service center. The header field of the calling message request includes roaming location information.
[0049] The cross-network service function entity receives a response message from the calling SMS service center for a caller's message request, and responds to the response message by sending an uplink forwarding SMS request response message to the GSM network side. The uplink forwarding SMS request response message carries SCCP source GT information, which is the address information of the cross-network service function entity as the SMS service center.
[0050] When the terminal is the called party and roaming on a GSM network,
[0051] The cross-network service function entity receives a called message request from the called SMS service center on the VoLTE network side. The called SMS service center determines that the terminal is registered with the cross-network service function entity based on third-party registration information.
[0052] The cross-network service function entity performs protocol conversion on the called party message request and sends a downlink forwarding SMS request message to the GSM network side. This downlink forwarding SMS request message carries SCCP destination GT information, which is the roaming network element address information.
[0053] The cross-network service function entity receives a response message from the GSM network side for a downlink forwarding SMS request. This response message carries SCCP destination GT information, which is the address information of the cross-network service function entity as the SMS service center.
[0054] As one possible implementation method, the data service is implemented in the following way:
[0055] The Cross-Network Service Function Entity receives an Update GPSR Location Request message from the GSM network side. Based on the mobile subscription identifier information in the message, it determines whether the terminal is allowed to register on the GSM network. If allowed, it temporarily stores the terminal's current location information and sends an Insert User Data Request message to the GSM network side. This message carries SCCP source GT information, which is the address information of the Cross-Network Service Function Entity as the Home Location Register.
[0056] The Cross-Network Service Function Entity receives an Insert User Data Response message from the GSM network side. This message carries SCCP destination GT information, which is the address information of the Home Location Register (HOME Register) used by the Cross-Network Service Function Entity, so that the GSM network side records the terminal's HOME Register address as the SCCP destination GT information.
[0057] In response to the Insert User Data Response Message, the Cross-Network Service Function Entity records the Serving GPRS Support Node (SGSN) address of the terminal as the roaming SGSN address and sends an Update GPSR Location Response Message to the GSM network side. This message carries SCCP source GT information, which is the address information of the Cross-Network Service Function Entity as the Home Location Register.
[0058] As one possible implementation method, the access control service is implemented in the following way:
[0059] A cross-network service function entity sends a user data request message to the GSM network side. This message carries SCCP destination GT information and SCCP source GT information. The SCCP destination GT information is the roaming network element address information, and the SCCP source GT information is the address information of the cross-network service function entity as its home location register.
[0060] Receive user data response messages from the GSM network side. These messages carry SCCP destination GT information, which is the address information of the cross-network service function entity as the home location register.
[0061] in,
[0062] User data request messages include: insert user data request messages or delete user data request messages.
[0063] A second aspect of this application provides an apparatus for implementing communication services for a VoLTE (Voice over LTE) network terminal roaming to a GSM (Global System for Mobile Communications) network. The apparatus includes a memory and a processor. The memory stores a computer program, and the processor is configured to execute the computer program to implement the steps of any of the above-described methods for implementing communication services for a VoLTE network terminal roaming to a GSM network.
[0064] The communication service implementation method for VoLTE network terminals roaming to GSM networks provided in this application embodiment, through the interface between the cross-network service function entity used to handle communication services roaming from VoLTE network to GSM network and the GSM network, makes the cross-network service function entity equivalent to the home network, telephone number mapping network element, and service call session control function network element. This allows the CS domain in the VoLTE network to be decommissioned and taken offline without the need to modify the existing network elements on the VoLTE network side, which helps to reduce the maintenance and operation costs of the communication system. Attached Figure Description
[0065] Figure 1 This is a flowchart illustrating a method for implementing communication services from a Long Term Evolution (LTE) Voice Bearer (VoLTE) network terminal to a Global System for Mobile Communications (GSM) network, according to an embodiment of this application.
[0066] Figure 2 This is a schematic diagram of a network system according to an embodiment of this application.
[0067] Figure 3 This is a schematic diagram of the authentication process when a VoLTE network terminal roams to a GSM network in this embodiment.
[0068] Figure 4 This is a schematic diagram of a process for the initial registration of a VoLTE network terminal when roaming to a GSM network in this embodiment.
[0069] Figure 5 This is a schematic diagram illustrating a process for updating and registering a location update when a VoLTE network terminal roams between different MSCs / VLRs on the GSM network side in this embodiment.
[0070] Figure 6 This is a schematic diagram of a process for initiating location clearing after leaving GSM in this embodiment.
[0071] Figure 7 This is a schematic diagram illustrating a callee voice service process when a terminal is roaming on a GSM network in this embodiment.
[0072] Figure 8 This is a schematic diagram illustrating a process for sending SMS messages (i.e., outgoing SMS messages) when the terminal is roaming on a GSM network in this embodiment.
[0073] Figure 9 This is a schematic diagram illustrating a process for receiving SMS messages (called SMS messages) when the terminal is roaming on a GSM network in this embodiment.
[0074] Figure 10 This is a schematic diagram illustrating a process for a terminal to perform data services when roaming to a GSM network in this embodiment.
[0075] Figure 11 This is a schematic diagram illustrating the process of controlling permissions for a VoLTE terminal when it registers with a GSM network in this embodiment.
[0076] Figure 12 This is a schematic diagram of a communication service implementation device for a VoLTE network terminal roaming to a GSM network according to an embodiment of this application. Detailed Implementation
[0077] To make the objectives, technical means, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0078] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0079] This application embodiment implements cross-network communication services through a cross-network service function entity for processing communication services roaming from a VoLTE network to a GSM network. During the process of at least achieving the first registration service on the GSM network, it acts as a logical home location register to forward signaling with the GSM network.
[0080] See Figure 1 As shown, Figure 1 This is a flowchart illustrating a method for implementing communication services from a Long Term Evolution (LTE) Voice over LTE (VoLTE) network terminal roaming to a Global System for Mobile Communications (GSM) network, according to an embodiment of this application. The method includes:
[0081] Step 101: The cross-network service function entity receives an update location request message initiated from the GSM network side. This update location request message carries mobile subscription identification information.
[0082] Step 102: Based on the mobile subscription identifier information, determine whether the terminal is allowed to register on the GSM network.
[0083] Step 103: If permitted, send an Insert User Data Request message to the GSM network side. This message carries subscription information and SCCP Source Global Address (GT) information from the Signalling Connection Control (SCCP) part, so that: the GSM network side records the mobile subscription identifier information as the terminal number and records the SCCP Source GT information as the terminal's home address information. The SCCP Source GT information is the address information used as the Home Location Register across network service function entities.
[0084] Step 104: Receive the Insert User Data Response Message from the GSM network side and send an Update Location Response Message to the GSM network side to complete the initial registration with the GSM network;
[0085] in,
[0086] The Insert User Data Response Message carries SCCP Target GT Information (SCCPDA), which is the address information of cross-network service function entities.
[0087] The message is transmitted across networks via a signaling transfer point.
[0088] As an example, communication services roaming from a VoLTE network to a GSM network include at least one of the following:
[0089] Authentication services used for terminal authentication.
[0090] Update registration service used for location updates between different roaming network elements in a GSM network
[0091] Location clearing service is used to clear location information after leaving the GSM network.
[0092] Caller voice service in GSM network
[0093] SMS service for callers and recipients in GSM networks
[0094] Data services in GSM networks
[0095] Access control services in GSM networks.
[0096] In the aforementioned communication services, cross-network service function entities are logically defined as SMS exchange center network elements, Service Call Session Control Function (S-CSCF) network elements, and Telephone Number Mapping (ENUM) network elements.
[0097] It should be understood that the cross-network service function entity in the embodiments of this application can be a distributed cluster communication device, a centralized server, or a software platform, and this application does not limit it in this regard.
[0098] The communication service implementation method for VoLTE network terminals roaming to GSM networks provided in this application embodiment can handle GSM network signaling by interfacing with the GSM network through a cross-network service function entity. The CS domain network can be completely taken offline, eliminating the need for significant maintenance costs. It has no impact on the various network elements in the VoLTE network, and the cross-network service function entity is just one of the basic network elements in the VoLTE network. The cross-network service function entity provides a portal for VoLTE terminals to log in to the GSM network, enabling centralized management of all related communication services.
[0099] To facilitate understanding of the embodiments of this application, the following description uses VoLTE networks in the domestic area and GSM networks in the overseas area as examples. It should be understood that the embodiments of this application are not limited to this and can be applied to cross-network communication services in any region.
[0100] See Figure 2 As shown, Figure 2 This is a schematic diagram of a network system according to an embodiment of this application. The VoLTE network side includes existing VoLTE functional entities, which include: Home Subscriber Server (HSS), Domain Name System (ENUM DNS), Media Gateway Control Function (MGCF), Short Message Service Center (SMSC), Multimedia Domain Service Switching Function (IMS-SSF), Multimedia Resource Function Controller / Multimedia Resource Function Processor (MRFC / MRFP), Multimedia Telephone (MMTEL), Service Edge Access Control / Proxy Session Control Function (BAC / P-CSCF), Customer Relationship Management (CRM) & Computer-Aided Communication (CMC).
[0101] HSS, ENUM DNS, MGCF, SMSC, IMS-SSF, MRFC / MRFP, MMTEL, and BAC / P-CSCF establish communication connections sequentially through a tunnel to form a VoLTE network. CRM & CMC establish communication connections with HSS and ENUM DNS respectively through an IP link.
[0102] The system also includes a cross-network service function entity, referred to as VtoG (Volte network to GSM network) for ease of description. VtoG establishes communication connections with HSS, ENUM DNS, MGCF, SMSC, and CRM&CMC via IP links, and establishes a communication connection with the first ISTP (International Signal Transfer Point) within the territory via M3UA Link.
[0103] VtoG provides the logic for VoLTE terminals to authenticate, register, and perform voice, SMS, and internet access when logging into overseas GSM networks; it also stores and manages user static data and real-time roaming data. Through interconnection with the signaling network and processing of relevant VoLTE and GSM network signaling translation and conversion processes, it possesses the functional entities necessary for services to function normally under VoLTE networks and overseas GSM networks, enabling voice, SMS, and data functions.
[0104] The first ISTP completes signaling forwarding and connects to the second ISTP, which serves as the overseas signaling transfer point (STP), via M3UA Link. It performs destination global address (GT, Global Table) routing analysis for the SMS service center and forwards Mobile Application Part (MAP) messages from overseas GSM networks to VtoG.
[0105] The GSM network side includes: Home Location Register (HLR), Serving GPRS Support Node (SGSN), Short Message Service Center (SMSC), Mobile Switching Center (MSC) / Visitor Location Register (VLR) / Service Control Point (SSP), Gateway Mobile Switching Center (GMSC) / Service Control Point (SSP), International Switching Center (ISC), and a second ISTP, all connected sequentially via trunk.
[0106] As an example, the cross-network communication services involved in the communication service of this embodiment include at least one of the following: authentication, registration, called party voice, calling party SMS, called party SMS, data, and access control. Registration includes: initial registration, updated registration, and location clearing.
[0107] See Figure 3 As shown, Figure 3 This is a schematic diagram illustrating the authentication process when a VoLTE network terminal roams to a GSM network in this embodiment. It includes:
[0108] Step 301: The VLR on the GSM network side sends an authentication request message (AUTH), which carries the GSM network International Mobile Subscriber Identity Information (G-IMIS). The authentication request message is transmitted to the first ISTP via the second ISTP.
[0109] Step 302: The first ISTP forwards the authentication message to the VtoG, where the first ISTP and VtoG essentially form the terminal's home network.
[0110] Step 303: The VtoG sends an authentication response message (AUTH Response) to the first ISTP based on the authentication request message. This message carries the terminal's authentication vector set.
[0111] Step 304: The first ISTP forwards the authentication response message to the second ISTP, which then forwards it to the VLR on the GSM network side so that the VIR can perform authentication.
[0112] See Figure 4 As shown, Figure 4 This is a schematic diagram illustrating the initial registration process of a VoLTE network terminal roaming to a GSM network in this embodiment. This process is the location registration initiated when the terminal first powers on after entering the GSM network from the VoLTE network, or when roaming in a powered-on state, and includes:
[0113] Step 401: The terminal initiates the authentication process from the MSC / VLR on the GSM network side, i.e. Figure 3 The authentication process;
[0114] Step 402a: After authentication by the GSM network, the terminal sends an Update Location Request message (UPDATE_LOCATION) from the MSC / VLR on the GSM network to the VtoG to register the visited location. The UPDATE_LOCATION message carries International Mobile Subscriber Identity (IMSI) information and is forwarded to the first ISTP via the second ISTP.
[0115] Step 402b: The first ISTP forwards the UPDATE_LOCATION message from the GSM network side to the VtoG via GT addressing; the VtoG determines whether the terminal is allowed to register on the GSM network based on the IMSI contained in the UPDATE_LOCATION message.
[0116] Step 403: If not allowed, the VtoG returns an Update Location Response (UPDATE_LOCATION_Ack) message to the GSM network side. This message carries failure reason information, such as "roaming notallowed". The message is forwarded to the second ISTP via the first ISTP and then returned to the MSC / VLR on the GSM network side by the second ISTP.
[0117] Step 404: If permitted, the VtoG, acting as the HLR, retrieves the data information stored when the user opened the account and sends an Insert User Data (ISD) request message. This ISD request message carries the source GT information of the Signaling Connection Control Part (SCCP) and is sent to the second ISTP via the first ISTP. The second ISTP then forwards it to the MSC / VLR on the GSM network side. The user number is the MDN number and related authorization and subscription information at the time of account opening, etc. The SCCP source GT address is the address of the VtoG as the HLR, and the MAP session ID remains unchanged.
[0118] Step 405: In response to the ISD request message, the MSC / VLR on the GSM network side records the terminal's registration number as a Mobile Subscriber Number (MDN), records the home HLR address as the VtoG address, and returns an ISD response message (ISD_Ack). The ISD_Ack message carries SCCP destination GT information, which is the VtoG address as the HLR. The ISD_Ack message passes through the second ISTP and the first ISTP sequentially to the VtoG.
[0119] Step 406: After receiving the ISD_Ack message, the VtoG sends an UPDATE_LOCATION_Ack message to the MSC / VLR on the GSM network side to complete the MAP location update; the UPDATE_LOCATION_Ack message is sequentially sent to the MSC / VLR on the GSM network side via the first ISTP and the second ISTP.
[0120] Step 407: VtoG sends a third-party registration message (REGISTER) to the SMS service center on the VoLTE network side to which the terminal belongs. The access-domain value of the P-Access-Network-Info header field in the REGISTER message includes the terminal's roaming location information.
[0121] Step 408: The VoLTE network-side SMS service center records the VtoG address as the terminal registration service call session control function (S-CSCF) address and returns a REGISTER response message to the VtoG.
[0122] See Figure 5 As shown, Figure 5 This is a schematic diagram illustrating a process for a VoLTE network terminal initiating a location update registration when roaming between different MSCs / VLRs on the GSM network side, as described in this embodiment. It includes:
[0123] Step 501: After the terminal roams from the first roaming network element (e.g., MSC1 / VLR1) on the GSM network side to the second MSC2 / VLR2, the currently visited second roaming network element (e.g., MSC2 / VLR2) authenticates with VtoG. This process is similar to... Figure 3 The authentication process is the same;
[0124] Step 502: After authentication is successful, MSC2 / VLR2 sends an UPDATE_LOCATION message to VtoG. This message passes through the second ISTP and the first ISTP before reaching VtoG.
[0125] Step 503: VtoG checks the terminal status to determine whether the terminal is allowed to log in to MSC2 / VLR2.
[0126] If not allowed, VtoG returns an UPDATE_LOCATION_Ack message to MSC2 / VLR2 with the reason "roaming not allowed".
[0127] If network login is allowed, VtoG sends a Cancel Location Request (CANCEL LOCATION) message to MSC1 / VLR1.
[0128] Step 504, MSC1 / VLR1 returns a CANCEL LOCATION response to VtoG;
[0129] Step 505: After receiving the response, VtoG updates the stored terminal location information, that is, updates the current user location information to MSC2 / VLR2, and sends an ISD message to MSC2 / VLR2. This message passes through the first ISTP and the second ISTP to MSC2 / VLR2 in sequence.
[0130] Step 506: MSC2 / VLR2 records the HLR address to which the user belongs as the address of VtoG as the HLR, and returns an ISD response message (ISD_Ack) to VtoG.
[0131] Step 507: After receiving the ISD_Ack message, VtoG sends an UPDATE_LOCATION_Ack message to MSC2 / VLR2 on the GSM network side, thus completing the MAP location update.
[0132] Step 508: VtoG sends a third-party registration message (REGISTER) to the SMS service center on the VoLTE network side to which the user belongs.
[0133] Step 509: The VoLTE network-side SMS service center records the VtoG address as the user's registered S-CSCF address and sends a response message to the VtoG containing the third-party registration message.
[0134] See Figure 6 As shown, Figure 6 This is a schematic diagram illustrating a process for initiating location clearing after leaving GSM, as described in this embodiment. It includes:
[0135] Step 601: After the GSM network detects that the terminal has left the MSC / VLR, it initiates a PurgeMS (Purge Mobile Station Request) message; the PurgeMS message is transmitted to VtoG via ISTP.
[0136] Step 602: VtoG analyzes the MSC address in the PurgeMS message to determine if it is the registered MSC address of the current record.
[0137] If not, VtoG returns a PurgeMS response message to the MSC, which is then transmitted to the MSC via ISTP.
[0138] If so, VtoG sends an unregistered SMS third-party registration request message (UNREGISTER) to the VoLTE network-side SMS service center. The VoLTE network-side SMS service center returns a response message to VtoG. If VtoG determines that the terminal is not roaming on the GSM network at this time, it deletes the current roaming location information.
[0139] In the registration service of this embodiment, VtoG uses back-to-back translation between GSM network and VoLTE network elements to realize the registration function. VtoG acts as the HLR network element of the terminal in the GSM network, enabling the terminal to perform MAP login in the GSM network. At the same time, VtoG acts as the S-CSCF network element of the VoLTE network to initiate the third-party registration function of IP Multimedia Subsystem (IMS).
[0140] For outgoing voice services, the call initiation process is completed within the terminal's current network, without involving cross-network voice service processing. For example, when a terminal initiates a call while roaming on a GSM network, the call initiation process is a GSM network initiation process, and VtoG does not need to process this process; when a terminal initiates a call on its home VoLTE network, the call initiation process on the home VoLTE network is a normal VoLTE initiation process, and VtoG does not need to process this process.
[0141] See Figure 7 As shown, Figure 7 This is a schematic diagram illustrating a callee voice service process when a terminal is roaming on a GSM network in this embodiment. It includes:
[0142] Step 701: The called party's voice service is transferred to the S-CSCF in the VoLTE network, and the S-CSCF initiates an invite message to trigger the MMTEL service.
[0143] Step 702: MMTEL finds that the terminal is not registered under VoLTE. MMTEL inserts a preselected access code before the called number and returns the preselected access code and the called number in the invite message to S-CSCF.
[0144] Step 703: The S-CSCF initiates a preselected ENUM query request message to the Telephone Number Mapping (ENUM) of the called party's home telephone number.
[0145] Step 704: ENUM sends an ENUM query request message to VtoG based on the pre-selected access code;
[0146] Step 705: VtoG converts the ENUM query request into a Provide Roaming Number (PRN) request message of the GSM network MAP protocol and sends it to the first ISTP; the first ISTP forwards the PRN request message to the VLR on the GSM network side.
[0147] Step 706: The VLR on the GSM network side allocates a roaming number (MSRN) and sends the allocated roaming number along with a response message (PRN-Ack) in the PRN to the first ISTP; the first ISTP forwards the PRN-Ack message to the VtoG;
[0148] Step 707: VtoG obtains the roaming number from the PRN-Ack message and constructs an ENUM query response message, which carries the roaming number.
[0149] In step 708, ENUM forwards the ENUM query response message to S-CSCF, thus completing the roaming number addressing for the called party. The VtoG's participation in the called party process ends here.
[0150] Step 709: Based on the obtained roaming number, the S-CSCF performs call routing according to the outgoing call process, and connects the call to the MSC / VLR of the GSM network to handle the call.
[0151] See Figure 8 As shown, Figure 8 This is a schematic diagram illustrating a process for sending SMS messages (calling SMS messages) when a terminal is roaming on a GSM network, as described in this embodiment. It includes:
[0152] Step 801: The MSC on the GSM network side receives an uplink SMS request message (MO_SMS_REQUEST) from the terminal.
[0153] Step 802: The MSC / VLR on the GSM network side sends an uplink forwarding SMS request message (MO_FSM) to the first ISTP. The MO_FSM message also carries the SCCP destination GT address, which is the address of the VtoG as the SMSC. The first ISTP sends the MO_FSM message to the VtoG through GT addressing.
[0154] Step 803: After VtoG converts the SMS message to G-MAP and SIP protocol formats, it sends the SMS request message (MESSAGE) to the SMSC on the VoLTE network side. The MESSAGE request message carries MO-RP-DATA, where the access-domain value in the P-Access-Network-Info header field is the user's roaming location information.
[0155] Step 804: After receiving the MESSAGE request message, the SMSC on the VoLTE network side sends a 202 response message to VtoG to indicate that the SMS message has been received by the SMS service center.
[0156] Step 805: On the VoLTE network side, the calling SMS service center sends the SMS to the called SMS service center, and upon receiving a response, sends a MESSAGE request message to VtoG. This MESSAGE request message carries RP-ACK information.
[0157] Step 806, VtoG sends a 200 response message to the SMS service center.
[0158] Step 807: The VtoG forwards the MO_FSM response message, i.e., the uplink forwarded SMS response message (MO_FSM_ack), to the first ISTP. The first ISTP forwards the MO_FSM_ack message to the MSC on the GSM network side, completing the calling SMS process. Among them, MO_FSM_ack carries the SCCP source GT address, which is the address of the VtoG as the SMSC.
[0159] Step 808: The MSC / VLR on the GSM network side returns an uplink SMS response message (MO_SMS_RESPOND) to the terminal.
[0160] See Figure 9 As shown, Figure 9 This is a schematic diagram illustrating a process for receiving SMS messages (called SMS messages) when a terminal is roaming on a GSM network, as described in this embodiment. It includes:
[0161] Step 901: After receiving the SMS message sent by the calling terminal, the VoLTE network-side SMS service center sends a SIP protocol MESSAGE request message to VtoG, which carries MT-RP-DATA.
[0162] The calling terminal can be a VoLTE user or a non-VoLTE user. The SMS will eventually be sent to the VoLTE network-side SMS service center. The VoLTE network-side SMS service center knows that the user is registered in VtoG based on the previous third-party registration information of the called number. At this time, VtoG is equivalent to the S-CSCF role.
[0163] Step 902: After receiving the MESSAGE request message, VtoG sends a 200 response message to the VoLTE network-side SMS service center.
[0164] Step 903: The VtoG converts the SIP protocol SMS into a G-MAP protocol downlink forwarding SMS request message (MT_FSM) and sends it to the first ISTP. The first ISTP forwards the MT_FSM message to the MSC / VLR on the GSM network side. The MT_FSM message carries the SCCP destination GT address, which is the MSC / VLR in the roaming area.
[0165] Step 904: The MSC on the GSM network side sends the SMS to the terminal roaming to the GSM network and sends an MT_FSM response message, i.e., a downlink forwarding SMS response message (MT_FSM_ack), to the first ISTP. The first ISTP forwards the MT_FSM_ack message to the VtoG. The MT_FSM_ack message carries the SCCP destination GT address, which is the address of the VtoG as the SMSC.
[0166] Step 905: VtoG converts the MT_FSM_ack message of the MAP protocol into the SIP protocol and sends a MESSAGE request message to the VoLTE network-side SMS service center. This message carries RP-ACK.
[0167] Step 906: The VoLTE SMS service center returns a 202 response message to VtoG.
[0168] In this embodiment, the calling and called SMS service uses a back-to-back conversion between GSM and VoLTE signaling protocols to achieve cross-network SMS transmission. It converts SMS messages using the MAP protocol of the GSM network to SMS messages using the SIP protocol of the VoLTE network, thus realizing the conversion of called SMS messages; and it converts SMS messages using the SIP protocol of the VoLTE network to SMS messages using the MAP protocol of the GSM network, thus realizing the conversion of called SMS messages.
[0169] See Figure 10 As shown, Figure 10 This is a schematic diagram illustrating a process for a terminal roaming to a GSM network to perform data services, as described in this embodiment. It includes:
[0170] Step 1001: The terminal visits the SGSN on the GSM network side, and the SGSN initiates an authentication process to VtoG.
[0171] Step 1002: The SGSN on the GSM network side sends an Update GPSR Location Request message (UPDATE_GPSR_LOCATION) to the VtoG to register the location. The UPDATE_GPSR_LOCATION message is sent to the VtoG by the first ISTP via GT addressing.
[0172] Step 1003: VtoG determines whether the terminal is allowed to register under this network based on the IMSI information contained in the UPDATE_GPSR_LOCATION message.
[0173] If the control conditions do not allow it, VtoG returns a response message to the UPDATE_GPSR_LOCATION message, which is an update GPSR location response message (UPDATE_GPSR_LOCATION_Ack), carrying the reason for failure as "roaming notallowed".
[0174] If permitted, proceed to step 1004, whereby the VtoG temporarily stores the terminal's current location information and sends the ISD request message to the SGSN on the GSM network side via ISTP. The ISD request message carries the SCCP source GT address, which is the address of the VtoG as the HLR, and maintains the MAP session ID unchanged.
[0175] Step 1005: After receiving the ISD request message, the SGSN on the GSM network side records the HLR address to which the terminal belongs as the HLR address of the VtoG, and returns an ISD response message (ISD_Ack) to the VtoG. This message is sent to the VtoG by the first ISTP through GT addressing. The ISD_Ack message carries the SCCP destination GT address, which is the address of the VtoG as the HLR.
[0176] Step 1006: The VtoG returns an UPDATE_GPSR_LOCATION_Ack message to the GSM network and records the user's SGSN address as the roaming SGSN. The UPDATE_GPSR_LOCATION_Ack message carries the SCCP source GT address, which is the address of the VtoG as the HLR.
[0177] See Figure 11 As shown, Figure 11 This is a schematic diagram illustrating the process of controlling permissions for a VoLTE terminal when registering on a GSM network, as described in this embodiment. It includes:
[0178] Step 1101: When it is necessary to modify or delete the permissions of a VoLTE subscribed terminal, the VtoG sends a user data request message to the ISTP for the terminal. The user data request message carries the SCCP source GT address and the SCCP destination GT address. The SCCP source GT address is the address of the VtoG as the HLR, and the SCCP destination GT address is the address of the roaming MSC. The user data request message includes an ISD (Insert User Data) or DSD (Delete User Data) request message.
[0179] Step 1102: The first ISTP sends an ISD request message or a DSD request message to the MSC on the GSM network side based on the routing information.
[0180] Step 1103: After receiving the user data request message, the MSC on the GSM network side returns a user data response message. This message carries the SCCP destination GT address, which is the VtoG address used as the HLR address.
[0181] Step 1104: The user data response message is sent to VtoG via the first ISTP, thus completing the cross-network permission modification function.
[0182] See Figure 12 As shown, Figure 12This is a schematic diagram of a communication service implementation apparatus for a VoLTE network terminal roaming to a GSM network according to an embodiment of this application. The apparatus includes a memory and a processor. The memory stores a computer program, and the processor is configured to execute the computer program to implement the steps of the communication service implementation method for a VoLTE network terminal roaming to a GSM network according to an embodiment of this application.
[0183] The memory may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.
[0184] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.
[0185] This invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the communication service implementation method for a VoLTE network terminal roaming to a GSM network according to embodiments of this application.
[0186] For the device / network-side equipment / storage medium embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and relevant parts can be referred to in the description of the method embodiments.
[0187] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0188] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for implementing communication services when a VoLTE (Voice over LTE) network terminal roams to a GSM (Global System for Mobile Communications) network, characterized in that, The method includes: On the cross-network service function entity side used to handle communication services roaming from VoLTE network to GSM network, The cross-network service function entity receives an update location request message initiated from the GSM network side. This update location request message carries mobile subscription identification information. Based on the mobile subscription identifier information, determine whether the terminal is allowed to register on the GSM network. Where permitted, an Insert User Data Request message is sent to the GSM network side. This message carries subscription information and SCCP source global address (GT) information from the Signalling Connection Control (SCCP) section, so that: the GSM network side records the mobile subscription identifier information as the terminal number and records the SCCP source GT information as the terminal's home address information. The SCCP source GT information is the address information used as the Home Location Register (HLR) across network service function entities. The system receives an Insert User Data Response message from the GSM network side and sends an Update Location Response message to the GSM network side to complete the initial registration with the GSM network. The Insert User Data Response message carries SCCP target GT information, which is the address information of the cross-network service function entity. The Insert User Data Response message is sent to the cross-network service function entity by the first signaling transfer point through GT addressing. in, The message is transmitted across networks via a signaling transfer point.
2. The communication service implementation method according to claim 1, characterized in that, After sending the location update response message to the GSM network side, the process further includes: Send a third-party registration SMS message to the SMS service center on the VoLTE network side. The header field of the third-party registration SMS message includes the terminal roaming location information, so that the SMS service center records the cross-network service function entity address as the service call session control function (S-CSCF) address registered by the terminal. The communication services roaming from a VoLTE network to a GSM network include at least one of the following services: Authentication services used for terminal authentication. Update registration service used for location updates between different roaming network elements in a GSM network Location clearing service is used to clear location information after leaving the GSM network. Caller voice service in GSM network SMS service for callers and recipients in GSM networks Data services in GSM networks, Access control services in GSM networks.
3. The communication service implementation method according to claim 2, characterized in that, The authentication service is implemented in the following manner: The cross-network service function entity receives an authentication request message from the GSM network side. This authentication request message carries GSM network mobile subscription identification information. In response to the authentication request message, based on the GSM network mobile subscription identifier information in the authentication request message, an authentication response message is sent to the GSM network side. The authentication response message carries an authentication vector group corresponding to the GSM network mobile subscription identifier information to authenticate the terminal.
4. The communication service implementation method according to claim 2, characterized in that, The registration update service is implemented in the following manner: When a terminal switches from the first roaming network element to the second roaming network element in a GSM network The cross-network service function entity receives an update location request message from the second roaming network element on the GSM network side, and determines whether the terminal is allowed to log in to the second roaming network element. If permitted, send a location cancellation request message to the first roaming network element. Receive a location cancellation response message from the first roaming network element. In response to the location cancellation response message, the terminal's location information is updated to the location information of the second roaming network element, and an insert user data request message is sent to the second roaming network element. This user data request message carries SCCP source GT information, which is the address information of the cross-network service function entity as the home location register, so that: the second roaming network element records the terminal's home location register information as the SCCP source GT information. The system receives an Insert User Data Response message from the second roaming network element. This message carries SCCP target GT information, which is the address information of the cross-network service function entity as the home location register. In response to the user data response message, an update location response message is sent to the second roaming network element. This update location response message carries SCCP source GT information, which is the address information of the cross-network service function entity as the home location register. A third-party SMS registration message is sent to the SMS service center on the VoLTE network side. The header field of this third-party SMS registration message includes the terminal roaming location information, so that the SMS service center records the cross-network service function entity address as the S-CSCF address registered by the terminal.
5. The communication service implementation method according to claim 2, characterized in that, The location clearing service is implemented in the following manner: The cross-network service function entity receives a cleanup mobile station request message from the GSM network side. Based on the address from which the mobile station cleanup request message originated, determine whether it is the recorded registration address. If so, a cleanup mobile station response message is returned to the GSM network side. If not, a message to cancel third-party registration via SMS is sent to the SMS service center on the VoLTE network side, causing the SMS service center on the VoLTE network side to return a response message to cancel third-party registration via SMS. Based on this response message, the cross-network service function entity determines that the terminal is not roaming on the GSM network.
6. The communication service implementation method according to claim 2, characterized in that, The called party voice service is implemented in the following manner: When the terminal is the called party and roaming on a GSM network, The cross-network service function entity receives a telephone number mapping query request message from the VoLTE network side. This request message is sent by the VoLTE network side's called party home telephone number mapping domain name system in response to a preselected telephone number mapping query request message from the called party home S-CSCF. Specifically, the called party home S-CSCF receives a transferred called party voice service and triggers a multimedia call service request message to the telephone number mapping domain name system. The telephone number mapping domain name system finds that the terminal is not currently registered on the VoLTE network side and returns the preselected access code and called number to the called party home S-CSCF, so that the called party home S-CSCF sends a preselected telephone number mapping query request message to the called party home telephone number mapping domain name system. The cross-network service function entity responds to the phone number mapping query request message by converting it into a roaming number provision request message according to the MAP protocol and sending it to the GSM network side. The cross-network service function entity receives a roaming number provision response message from the GSM network side. This message carries the GSM network roaming number that the GSM network provides to the terminal. The cross-network service function entity obtains the GSM network roaming number from the roaming number response message, constructs a phone number mapping query message carrying the GSM network roaming number, and sends it to the VoLTE network so that the VoLTE network can conduct voice services with the GSM network based on the GSM network roaming number.
7. The communication service implementation method according to claim 2, characterized in that, The SMS service for both the calling and called parties is implemented in the following manner: When the terminal is the calling party and roaming on a GSM network, The cross-network service function entity receives an uplink forwarding SMS request message from the GSM network side. This uplink forwarding SMS request message carries SCCP destination GT information, which is the address of the cross-network service function entity as the SMS service center. The cross-network service function entity responds to the uplink forwarding SMS request message by performing protocol conversion on the uplink forwarding SMS request message and sending the calling message request to the VoLTE network-side calling SMS service center, so that the calling SMS service center forwards the calling message request to the called SMS service center. The header field of the calling message request includes roaming location information. The cross-network service function entity receives a response message from the calling SMS service center for a caller's message request, and responds to the response message by sending an uplink forwarding SMS request response message to the GSM network side. The uplink forwarding SMS request response message carries SCCP source GT information, which is the address information of the cross-network service function entity as the SMS service center. When the terminal is the called party and roaming on a GSM network, The cross-network service function entity receives a called message request from the called SMS service center on the VoLTE network side. The called SMS service center determines that the terminal is registered with the cross-network service function entity based on third-party registration information. The cross-network service function entity performs protocol conversion on the called party message request and sends a downlink forwarding SMS request message to the GSM network side. This downlink forwarding SMS request message carries SCCP destination GT information, which is the roaming network element address information. The cross-network service function entity receives a response message from the GSM network side for a downlink forwarding SMS request. This response message carries SCCP destination GT information, which is the address information of the cross-network service function entity as the SMS service center.
8. The communication service implementation method according to claim 2, characterized in that, The data service is implemented in the following manner: The Cross-Network Service Function Entity receives an Update GPSR Location Request message from the GSM network side. Based on the mobile subscription identifier information in the message, it determines whether the terminal is allowed to register on the GSM network. If allowed, it temporarily stores the terminal's current location information and sends an Insert User Data Request message to the GSM network side. This message carries SCCP source GT information, which is the address information of the Cross-Network Service Function Entity as the Home Location Register. The Cross-Network Service Function Entity receives an Insert User Data Response message from the GSM network side. This message carries SCCP destination GT information, which is the address information of the Home Location Register (HOME Register) used by the Cross-Network Service Function Entity, so that the GSM network side records the terminal's HOME Register address as the SCCP destination GT information. In response to the Insert User Data Response Message, the Cross-Network Service Function Entity records the Serving GPRS Support Node (SGSN) address of the terminal as the roaming SGSN address and sends an Update GPSR Location Response Message to the GSM network side. This message carries SCCP source GT information, which is the address information of the Cross-Network Service Function Entity as the Home Location Register.
9. The communication service implementation method according to claim 2, characterized in that, The access control service is implemented in the following manner: A cross-network service function entity sends a user data request message to the GSM network side. This message carries SCCP destination GT information and SCCP source GT information. The SCCP destination GT information is the roaming network element address information, and the SCCP source GT information is the address information of the cross-network service function entity as its home location register. Receive user data response messages from the GSM network side. These messages carry SCCP destination GT information, which is the address information of the cross-network service function entity as the home location register. in, User data request messages include: insert user data request messages or delete user data request messages.
10. A device for implementing communication services for a VoLTE network terminal roaming to a GSM network, characterized in that, The apparatus includes: a memory and a processor, the memory storing a computer program, and the processor being configured to execute the computer program to implement the steps of any of the methods for implementing communication services of a VoLTE network terminal roaming to a GSM network as described in claims 1 to 9.